INTRODUCTION: Upper tract urothelial carcinoma with neuroendocrine differentiation (UC-NE) is extremely rare and generally associated with aggressive behavior and poor prognosis. Optimal treatment strategies remain unclear, particularly regarding the role of nectin-4-targeted therapy. CASE PRESENTATION: A 61-year-old man was diagnosed with UC-NE of the renal pelvis. Laparoscopic nephroureterectomy revealed invasive UC-NE with lymphatic invasion (pT1, G2) and carcinoma in situ of the ureter (pTis, G1). Immunohistochemistry showed strong nectin-4 expression in the urothelial component but only weak to moderate expression in the neuroendocrine component. Ten months after surgery, para-aortic and bilateral pelvic lymph node recurrence developed. Treatment with enfortumab vedotin (EV) plus pembrolizumab achieved a complete response after 3 cycles, and remission was maintained with continued therapy. CONCLUSION: This case suggests that EV plus pembrolizumab may be effective for UC-NE and highlights the importance of evaluating nectin-4 and the tumor immune microenvironment when considering treatment strategies for this rare subtype.

Urothelial carcinoma (UC), which includes bladder carcinoma (accounting for 90-95% of cases) and upper urinary tract carcinoma (comprising 5-10%), is one of the most prevalent malignancies worldwide. For several decades, platinum-based chemotherapy has been the primary treatment modality for this disease. However, recent advancements have significantly transformed the therapeutic landscape for patients with UC. This transformation has been facilitated by the introduction of various treatment options, including immune checkpoint inhibitors targeting PD-L1 or PD-1, antibody-drug conjugates that target nectin-4 or trophoblast cell surface antigen 2 expressed on cancer cells, and fibroblast growth factor receptor (FGFR) inhibitors specifically indicated for Patients with UC with FGFR3 mutations. Although these novel therapies have demonstrated marked survival benefits for patients with locally advanced or metastatic UC, their efficacy can vary depending on the specific molecular profile present on cancer cells. In this review, we summarize the molecular classifications of UC and the corresponding treatment landscape associated with these classifications.

Radiotherapy (RT) for prostate cancer increases the risk of bladder cancer. The genomic landscape of bladder cancer following RT for prostate cancer and its differentiation from bladder cancers that develop without a history of pelvic RT remains unclear. We examined gene mutations in bladder cancers that developed following RT and those that developed without prior RT. Fourteen patients who developed primary bladder cancer following brachytherapy were categorized into radiation-associated bladder tumor (RA-BT) group, whereas 33 patients diagnosed with primary bladder cancer without a history of pelvic RT were classified into the bladder tumor (BT) group. The frequency of TERT promoter mutations was 35.7% and 63.6% in the RA-BT and BT groups, respectively (p = 0.112). Among the other characteristic mutations, FGFR3 and TP53 were frequently observed in both groups (FGFR3: RA-BT vs. BT, 14.3 vs. 42.4%; TP53: RA-BT vs. BT, 50 vs. 33.3%). Rare mutations in bladder cancer were more frequently observed in the RA-BT group, including ADGRB3 (28.6%), CBL (21.4%), TGM7 (21.4%), and BTK (14.3%). There were significantly more C → T substitutions in the RA-BT group than in the BT group. In our study, the genetic mutations in the RA-BT group had distinct features from those in the BT group.

The biological basis of the development of cancer of unknown primary (CUP) remains largely unknown, with no evidence of whether a common biological basis exists at present. Our previous multicenter clinical study predicted the primary site of CUP for site‑specific therapy. Concomitantly with the study, a microarray analysis of tumor mRNA samples obtained from 60 participants of the study with CUP was performed, and a gene expression profile specific to CUP was constructed. Several of the genes identified as being upregulated/downregulated in CUP could potentially be clinically useful common biomarkers of CUP. In the present study, to identify genes that may be more closely related to the development of CUP (characterized by its metastatic potential) among the upregulated genes, cell‑based small interfering RNA screening was performed in vitro, and two genes, protein kinase DNA‑activated catalytic subunit (PRKDC) and proteasome subunit β type‑4 (PSMB4), were identified to be possibly involved in the metastatic ability of CUP, since knockdown of these genes resulted in reduced migration of A549 cells. These genes were further knocked down in A549 cells using short hairpin RNAs (shRNAs) and the cells were implanted into the footpad of mice. Marked suppression of the metastatic ability of implanted cells from the footpad to the popliteal lymph node (LN) was observed in cells transfected with the shRNAs for PRKDC and PSMB4. In addition, bortezomib, a proteasome inhibitor, markedly reduced the ability of cells implanted into the footpad to metastasize to the LNs, as well as cell growth at the metastatic site, compared with vehicle or NU7447 (inhibitor of PRKDC). These findings indicated that proteasomal function activation augmented the metastatic ability of malignant CUP cells.

BACKGROUND: The efficacy of abiraterone acetate varies among patients with high-risk metastatic castration-sensitive prostate cancer (mCSPC). Both androgen receptor (AR) and cytokeratin 18 (CK18) are markers of the luminal lineage of prostate cancer, and their expression levels have been suggested to affect the response to androgen deprivation therapy (ADT). This study aimed to predict the efficacy of abiraterone acetate in high-risk mCSPC via immunohistochemical staining of biopsy specimens obtained at the time of prostate cancer diagnosis. METHODS: We retrospectively analyzed 44 patients treated with abiraterone acetate in combination with ADT. AR and CK18 expression in prostate biopsy specimens were assessed using immunohistochemical staining. RESULTS: AR and CK18 staining was not significantly associated with overall survival (OS). However, low AR staining was significantly associated with a shorter time to castration-resistant prostate cancer (TTCRPC) compared with high AR staining (log-rank test, p = 0.018). Similarly, low CK18 staining was significantly associated with a shorter TTCRPC compared with high CK18 staining (log-rank test, p = 0.037). CONCLUSIONS: Immunohistochemical analysis of AR or CK18 expression in biopsy specimens may serve as a predictive biomarker of high-risk mCSPC treated with abiraterone acetate. TRIAL REGISTRATION: None.

Chronic systemic inflammation caused by diseases such as ulcerative colitis (UC) and Crohn's disease (CD) increases the risk of developing colorectal cancer (CRC). Recent evidence indicates that patients with UC are more susceptible to prostate cancer (PCa), and individuals with PCa may also be at a higher risk of developing CRC. However, these relationships are not well defined. A better understanding of this phenomenon could improve the identification of high-risk populations. In this study, we characterized these relationships with experiments using preclinical mouse models of dextran sulfate sodium (DSS)-induced colitis (DSS-UC) and DSS/azoxymethane (AOM)-induced CRC (DSS/AOM-CRC) in wild-type and conditional transgenic mice of PCa. We showed that DSS-induced UC was more severe in mice with PCa and resulted in the development of CRC in the absence of AOM. We further showed that PCa-free mice that developed DSS-induced UC also showed histological changes in the normal prostate that resembled proliferative inflammatory atrophy. Finally, we used immunohistochemical immune profiling to show that mice with PCa-induced chronic systemic inflammation accumulated Gr1+ myeloid cells in the normal colon and exposure to DSS further enriched these cells in active colitis regions and colon tumors. Our study provides evidence to support a link between systemic chronic inflammation and cancer.

The human gut microbiota changes under the influence of environmental and genetic factors, affecting human health. Extensive studies have revealed that the gut microbiome is closely associated with many non-intestinal diseases. Among these, the influence of the gut microbiome on cancer biology and the efficacy of cancer therapy has attracted much attention. Prostate cancer cells are affected by direct contact with the microbiota of local tissues and urine, and a relationship between prostate cancer cells and the gut microbiota has been suggested. In the human gut microbiota, bacterial composition differs depending on prostate cancer characteristics, such as histological grade and castration resistance. Moreover, the involvement of several intestinal bacteria in testosterone metabolism has been demonstrated, suggesting that they may affect prostate cancer progression and treatment through this mechanism. Basic research indicates that the gut microbiome also plays an important role in the underlying biology of prostate cancer through multiple mechanisms owing to the activity of microbial-derived metabolites and components. In this review, we describe the evidence surrounding the emerging relationship between the gut microbiome and prostate cancer, termed the "gut-prostate axis."

Obesity and a high-fat diet are risk factors associated with prostate cancer, and lifestyle, especially diet, impacts the gut microbiome. The gut microbiome plays important roles in the development of several diseases, such as Alzheimer's disease, rheumatoid arthritis, and colon cancer. The analysis of feces from patients with prostate cancer by 16S rRNA sequencing has uncovered various associations between altered gut microbiomes and prostate cancer. Gut dysbiosis caused by the leakage of gut bacterial metabolites, such as short-chain fatty acids and lipopolysaccharide results in prostate cancer growth. Gut microbiota also play a role in the metabolism of androgen which could affect castration-resistant prostate cancer. Moreover, men with high-risk prostate cancer share a specific gut microbiome and treatments such as androgen-deprivation therapy alter the gut microbiome in a manner that favors prostate cancer growth. Thus, implementing interventions aiming to modify lifestyle or altering the gut microbiome with prebiotics or probiotics may curtail the development of prostate cancer. From this perspective, the "Gut-Prostate Axis" plays a fundamental bidirectional role in prostate cancer biology and should be considered when screening and treating prostate cancer patients.

BACKGROUND: The Biocartis Idylla™ platform is a fully automated, real-time PCR-based diagnostic system. The Idylla™ KRAS and NRAS-BRAF Mutation Tests have been developed for the qualitative detection of mutations in KRAS, NRAS and BRAF genes, facilitating the genomic profiling of patients with colorectal cancer. The aim of the present study was to evaluate clinical performances of these tests in Japan. METHODS: The RAS and BRAF mutation statuses of 253 formalin-fixed paraffin-embedded (FFPE) colorectal cancer tissues were analyzed using the Investigational Use Only Idylla™ KRAS Mutation Test and the Idylla™ NRAS-BRAF Mutation Test and an in vitro diagnostics (IVD) kit (MEBGEN RASKET™-B kit). RESULTS: The success rate for obtaining a valid mutational data without retest of the Idylla tests was 97.6% (247/253): 111 KRAS mutations (43.8%), 9 NRAS mutations (3.6%), and 36 BRAF V600E mutations (14.2%) were detected using the Idylla tests. Compared with the MEBGEN RASKET-B results, the positive concordance rate was 97.4%, the negative concordance rate was 95.7%, and the overall concordance rate was 95.3% (κ = 0.919, 95% CI 0.871-0.967). The average turnaround time to Idylla™ KRAS and NRAS-BRAF Mutation Test was 5.6 working days (range: 3-11 days). CONCLUSION: This result demonstrates a high concordance between the Idylla™ KRAS and NRAS-BRAF Mutation Tests and an existing IVD kit. In this manner, the Idylla™ mutation tests were validated for the detection of clinically significant KRAS, NRAS, and BRAF mutations in FFPE samples from colorectal cancer patients.

The gut microbiome is linked to several diseases such as Alzheimer's disease, rheumatoid arthritis, and colon cancer. The gut microbiome is also associated with the modulation of immune function, resulting in a different response to immune checkpoint therapy. The gut microbiome differs according to lifestyle, diet, sex, race, genetic background, and country. Lifestyle, especially diet, plays an important role in the development and progression of prostate cancer. Recent studies have revealed a connection between the gut microbiome and prostate cancer. A high-fat diet causes gut dysbiosis and gut bacterial metabolites, such as short-chain fatty acids and phospholipids that enter systemic circulation result in promoting prostate cancer growth. Additionally, the gut microbiota can serve as a source of testosterone, which affects prostate cancer progression. Men with castration-resistant prostate cancer have an increased abundance of gut bacteria with androgenic functions. Men with high-risk prostate cancer share a specific gut microbial profile and profiling gut microbiota could be a potentially effective tool to screen men with high-risk prostate cancer. Lifestyle modifications can improve the gut microbiome. Furthermore, altering the gut microbiome using prebiotic or probiotic interventions may prevent or delay prostate cancer development. Further study into the "Gut-Prostate Axis" would help in the discovery of new strategies for the prevention, screening, and treatment of prostate cancer.

BACKGROUND/PURPOSE OF THE STUDY: Tumor heterogeneity based on copy number variations is associated with the evolution of cancer and its clinical grade. Clonal composition (CC) represents the number of clones based on the distribution of B-allele frequency (BAF) obtained from a genome-wide single nucleotide polymorphism (SNP) array. A higher CC number represents a high degree of heterogeneity. We hypothesized and evaluated that the CC number in hepatocellular carcinoma (HCC) tissues might be associated with the clinical outcomes of patients. METHODS: Somatic mutation, whole transcriptome, and CC number based on copy number variations of 36 frozen tissue samples of operably resected HCC tissues were analyzed by targeted deep sequencing, transcriptome analysis, and SNP array. RESULTS: The samples were classified into the heterogeneous tumors as poly-CC (n = 26) and the homogeneous tumors as mono-CC (n = 8). The patients with poly-CC had a higher rate of early recurrence and a significantly shorter recurrence-free survival period than the mono-CC patients (7.0 months vs. not reached, p = 0.0084). No differences in pathogenic non-synonymous mutations, such as TP53, were observed between the two groups when targeted deep sequencing was applied. A transcriptome analysis showed that cell cycle-related pathways were enriched in the poly-CC tumors, compared to the mono-CC tumors. Poly-CC HCC is highly proliferative and has a high risk of early recurrence. CONCLUSION: CC is a possible candidate biomarker for predicting the risk of early postoperative recurrence and warrants further investigation.

Prostate cancer (PCa) is the most common malignancy in men worldwide, thus developing effective prevention strategies remain a critical challenge. Insulin-like growth factor 1 (IGF-1) is produced mainly in the liver by growth hormone signaling and is necessary for normal physical growth. However, several studies have shown an association between increased levels of circulating IGF-1 and the risk of developing solid malignancies, including PCa. Because the IGF-1 receptor is overexpressed in PCa, IGF-1 can accelerate PCa growth by activating phosphoinositide 3-kinase and mitogen-activated protein kinase, or increasing sex hormone sensitivity. Short-chain fatty acids (SCFAs) are beneficial gut microbial metabolites, mainly because of their anti-inflammatory effects. However, we have demonstrated that gut microbiota-derived SCFAs increase the production of IGF-1 in the liver and prostate. This promotes the progression of PCa by the activation of IGF-1 receptor downstream signaling. In addition, the relative abundance of SCFA-producing bacteria, such as Alistipes, are increased in gut microbiomes of patients with high-grade PCa. IGF-1 production is therefore affected by the gut microbiome, dietary habits, and genetic background, and may play a central role in prostate carcinogenesis. The pro-tumor effects of bacteria and diet-derived metabolites might be potentially countered through dietary regimens and supplements. The specific diets or supplements that are effective are unclear. Further research into the "Gut-IGF-1-Prostate Axis" may help discover optimal diets and nutritional supplements that could be implemented for prevention of PCa.

Immune checkpoint inhibitors (ICIs) have become the standard of care for several cancers. However, ICI therapy has also been associated with various immune-related adverse events (irAEs). Clinical manifestations of immune-related colitis resemble those of inflammatory bowel diseases such as ulcerative colitis (UC). The composition of the bowel microflora is thought to influence the development of inflammatory bowel disease and irAE colitis. We profiled the gene expressions and microbe compositions of colonic mucosa from patients with solid cancers receiving anti-PD-L1 antibody treatment; we then compared the expression profiles associated with irAE colitis with those associated with UC. The pathway enrichment analysis revealed functional similarities between inflamed regions of irAE colitis and UC. The common enriched pathways included leukocyte extravasation and immune responses, whereas non-inflamed mucosa from patients with irAE colitis was distinct from patients with UC and was characterized by the recruitment of immune cells. A similarity between the microbiota profiles was also identified. A decreased abundance of Bacteroides species was observed in inflamed regions from both irAE colitis and UC based on a microbiota composition analysis of 16S rDNA sequencing. Pathways associated with molecule transport systems, including fatty acids, were enriched in inflamed and non-inflamed irAE colitis and inflamed UC, similar to Piphillin-inferred KEGG pathways. While UC is characterized by local regions of inflammation, ICI treatment extends to non-inflammatory regions of the colonial mucosa where immune cells are reconstituted. This analysis of the similarity and heterogeneity of irAE colitis and UC provides important information for the management of irAE colitis.

Recently, combination therapy including immune checkpoint inhibition (ICI) has proven to be effective as first-line therapy for patients with metastatic renal cell carcinoma. Although the first-line combination therapies with ICI have shown clinical benefit, a number of patients require second-line treatment. We report a 60-year-old man with metastatic renal cell carcinoma who was treated with pazopanib soon after nivolumab plus ipilimumab combination therapy. He experienced Grade 3 disseminated intravascular coagulation (DIC). We suspect that this was caused by an interaction between pazopanib and nivolumab even though ICI therapy was discontinued. He was treated with thrombomodulin and platelet transfusion and recovered from DIC. Treatment with pazopanib was subsequently restarted. No evidence of DIC was observed thereafter. This severe adverse reaction may have been induced by an interaction between activated proinflammatory immune cells and cytokines from an exacerbated inflammatory state and pazopanib. This report highlights the need to perform careful monitoring of patients who receive molecular targeted therapy after ICI-based immunotherapy.

Immune checkpoint inhibitors (ICIs) are widely used to treat various malignancies. Although the gut microbiome is known to influence the efficacy of ICIs on epithelial tumors, the functional interactions between gut taxa and colonic mucosa remain poorly understood. Here we performed transcriptomic profiling and 16S rRNA sequencing to investigate the relationships between mucosal gene expression and microbial composition with ICI responses and gastrointestinal immune-related adverse events (GI irAEs). In responders, genes related to DNA repair and cell cycle signatures were enriched in responders whereas signatures related to innate immune response, NFAT and IFN-γ signaling pathways were enriched in nonresponders. Gut microbial composition revealed an association between moderate GI irAE and favorable response to ICI therapy. Favorable therapeutic responses to ICI and GI irAE treatments were associated with taxa classified as Enterobacteriaceae and were related to ribonucleoprotein complex biogenesis, cytokine-mediated signaling pathway, tRNA metabolic process, and ribonucleoprotein complex assembly in the colon. These findings open new perspectives for improving the efficacy and safety of cancer immunotherapy.

Colitis is a risk factor for colorectal cancer (CRC) and can change the dynamics of gut microbiota, leading to dysbiosis and contributing to carcinogenesis. The functional interactions between colitis-associated CRC and microbiota remain unknown. In this study, colitis and CRC were induced in BALB/c mice by the administration of dextran sodium sulfate (DSS) and/or azoxymethane (AOM). Whole transcriptome profiling of normal colon was then performed, and gene set enrichment analysis (GSEA) revealed enriched fatty acid metabolism, oxidative phosphorylation, and PI3K-Akt-mTOR signaling in the tissues from DSS/AOM mice. Additionally, immunohistochemical staining showed increased expression levels of phosphorylated S6 ribosomal protein, a downstream target of the PI3K-Akt-mTOR pathway in the inflamed mucosa of DSS/AOM mice. Fecal microbes were characterized using 16S rDNA gene sequencing. Redundancy analysis demonstrated a significant dissimilarity between the DSS/AOM group and the others. Functional analysis inferred from microbial composition showed enrichments of the sphingolipid signal and lipoarabinomannan biosynthetic pathways. This study provides additional insights into alterations associated with DSS/AOM-induced colitis and associates PI3K-Akt-mTOR, sphingolipid-signaling and lipoarabinomannan biosynthetic pathways in mouse DSS/AOM-induced colitis.

The present study investigated the antitumor activity and chemopreventive effects of a nanoparticle formulation of curcumin in preclinical models of mouse Pten-deficient prostate cancer. The antitumor activity of the nanoparticle curcumin was evaluated in mouse castration-naïve (7113-D3) and castration-resistant prostate cancer (2945-E10) derived cell lines in vitro. Cell viability was reduced in both cell lines in a dose and time-dependent manner. The effects of long-term dietary supplementation with the nanoparticle curcumin formulation were evaluated in a conditional Pten-deficient mouse model. Prostate tissues from Pten-deficient prostate cancers were obtained after sixteen weeks of dietary supplementation of 76 mg/kg/day or 380 mg/kg/day nanoparticle curcumin. Daily supplementation of nanoparticle curcumin did not affect mouse bodyweights or spleen size but did result in enlargement of the liver. Dietary supplementation did not influence tumor burden, however, mice fed high-dose curcumin had lower cancer cell proliferation rates at 12 and 16 weeks of age. Together, these results show that daily supplementation of a nanoparticle formulation of curcumin is tolerable and suggest that curcumin could have chemopreventive activity in early-stage prostate cancer.

Sustained therapeutic responses from traditional and next-generation antiandrogen therapies remain elusive in clinical practice due to inherent and/or acquired resistance resulting in persistent androgen receptor (AR) activity. Antisense oligonucleotides (ASO) have the ability to block target gene expression and associated protein products and provide an alternate treatment strategy for castration-resistant prostate cancer (CRPC). We demonstrate the efficacy and therapeutic potential of this approach with a Generation-2.5 ASO targeting the mouse AR in genetically engineered models of prostate cancer. Furthermore, reciprocal feedback between AR and PI3K/AKT signaling was circumvented using a combination approach of AR-ASO therapy with the potent pan-AKT inhibitor, AZD5363. This treatment strategy effectively improved treatment responses and prolonged survival in a clinically relevant mouse model of advanced CRPC. Thus, our data provide preclinical evidence to support a combination strategy of next-generation ASOs targeting AR in combination with AKT inhibition as a potentially beneficial treatment approach for CRPC.

BACKGROUND: HOX genes encode transcription factors that play key roles in modulating normal tissue morphogenesis, differentiation and homeostasis. Disruption of normal HOX gene expression occurs frequently in human cancers and is associated with both tumor promoting and suppressing activities. Among these is, HOXA10, a pleiotropic gene that is critical for normal prostate development. In this study we characterized HOXA10 expression in human and mouse PCa to gain insights into its clinical significance. METHODS: A meta-analysis of HOXA10 mRNA expression was carried out across several publicly available data sets. Expression of HOXA10 protein expression was assessed by immunohistochemistry (IHC) using human radical prostatectomy (RP) cases. We correlated HOXA10 expression to clinicopathological features and investigated its relationship to biochemical recurrence (BCR) after RP by the Kaplan-Meier method. HOXA10 mRNA and IHC protein expression was also examined in a mouse model of Pten-null PCa. RESULTS: A meta-analysis of HOXA10 gene expression indicated dysregulated expression of HOXA10 in human PCa. IHC profiling of HOXA10 revealed inverse correlations between HOXA10 expression and Gleason pattern, Gleason score, and pathological stage (P < 0.01). Patients with low expression profiles of HOXA10 were associated with a higher risk of BCR, (OR, 3.54; 95%CI, 1.21-16.14; P = 0.049) whereas patients with high HOXA10 expression experienced longer times to BCR (P = 0.045). However, HOXA10 was not an independent predictor of BCR (OR, 1.52; 95%CI, 0.42-5.54; P = 0.52). Evaluation of expression patterns of HOXA10 in mouse prostate tumors mimicked that of humans. CONCLUSIONS: Our findings show that HOXA10 expression is inversely associated with tumor differentiation and high HOXA10 expression is associated with improved BCR-free survival. This study provides human and mouse evidence to suggest tumor suppressive roles for HOXA10 in the context of prostate cancer.

Phosphatase and tensin homolog (PTEN) deficiency is associated with development, progression, and metastasis of various cancers. However, changes in gene expression associated with PTEN deficiency have not been fully characterized. To explore genes with altered expression in PTEN‑deficient cells, the present study generated a PTEN‑knockout cell line (ΔPTEN) from a mouse prostate cancer‑derived cell line using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‑associated protein 9 (CRISPR/Cas9) gene editing system. Following transfection of the CRISPR/Cas9 construct, DNA sequencing was performed to identify deletion of the Pten locus and PTEN inactivation was verified by western blotting. The ΔPTEN cell line exhibited enhanced RAC‑alpha serine/threonine‑protein kinase phosphorylation and cyclin D1 expression. In addition, an increase in cell proliferation and colony formation was observed in the ΔPTEN cell line. Gene expression profiling experiments were analyzed with microarray and microRNA (miRNA) arrays. In the microarray analysis, 111 genes exhibited ≥10‑fold increased expression compared with the parent strain and mock cell line and 23 genes were downregulated. The only miRNA with increased expression of 10‑fold or more was mmu‑miR‑210‑3p. Genes with enhanced expression included genes involved in the development, progression, and metastasis of cancer such as Tet methylcytosine dioxygenase 1, twist family BHLH transcription factor 2, C‑fos‑induced growth factor and Wingless‑Type MMTV Integration Site Family, Member 3, and genes involved in immunosuppression such as Arginase 1. The results of the present study suggest that PTEN deficiency mobilizes a variety of genes critical for cancer cell survival and host immune evasion.

PURPOSE OF REVIEW: In this review, we present the progress and current landscape for prostate cancer immunotherapy and overview recent scientific findings that shed novel insights into immunoresistance and discuss potential therapeutic strategies. RECENT FINDINGS: Prostate cancer immunogenicity is hampered by a highly immunosuppressive microenvironment and low mutation burden. Complex interactions between resident immunosuppressive cells such regulatory T cells, macrophages, myeloid-derived suppressor cells, and cancer cells cooperate to suppress antitumor immune responses and promote disease progression. A biphasic approach that boosts tumor immunogenicity and blockade of immunosuppressive pathways will most likely be required in order to produce meaningful therapeutic responses. SUMMARY: Significant advances have shed new light on prostate cancer immunology. These findings should enhance the development of immunotherapeutic strategies, especially when used in combination with other cancer treatments.

The PI3K/AKT pathway is frequently altered in advanced human prostate cancer mainly through the loss of functional PTEN, and presents as potential target for personalized therapy. Our aim was to determine the therapeutic potential of the pan-AKT inhibitor, AZD5363, in PTEN-deficient prostate cancer. Here we used a genetically engineered mouse (GEM) model of PTEN-deficient prostate cancer to evaluate the in vivo pharmacodynamic and antitumor activity of AZD5363 in castration-naïve and castration-resistant prostate cancer. An additional GEM model, based on the concomitant inactivation of PTEN and Trp53 (P53), was established as an aggressive model of advanced prostate cancer and was used to further evaluate clinically relevant endpoints after treatment with AZD5363. In vivo pharmacodynamic studies demonstrated that AZD5363 effectively inhibited downstream targets of AKT. AZD5363 monotherapy significantly reduced growth of tumors in castration-naïve and castration-resistant models of PTEN-deficient prostate cancer. More importantly, AZD5363 significantly delayed tumor growth and improved overall survival and progression-free survival in PTEN/P53 double knockout mice. Our findings demonstrate that AZD5363 is effective against GEM models of PTEN-deficient prostate cancer and provide lines of evidence to support further investigation into the development of treatment strategies targeting AKT for the treatment of PTEN-deficient prostate cancer.

BACKGROUND: We generated a mouse model of prostate cancer based on the adult-prostate-specific inactivation of phosphatase and tensin homolog (PTEN) using the Cre-loxP system. The potential of our mice as a useful animal model was examined by evaluating the chemopreventive efficacy of the anti-androgen, chlormadinone acetate (CMA). MATERIALS AND METHODS: Six-week-old mice were treated subcutaneously with 50 μg/g of CMA three times a week for 9 or 14 weeks and sacrificed at weeks 15 and 20. Macroscopic change of the entire genitourinary tract (GUT) and histologically evident prostate gland tumor development were evaluated. Proliferation and apoptosis status in the prostate were examined by immunohistochemistry. RESULTS: CMA triggered significant shrinkage of not only the GUT but also prostate glands at 15 weeks compared to the control (p=0.017 and p=0.010, respectively), and the trend became more marked after a further five-weeks of treatment. The onset of prostate adenocarcinoma was not prevented but the proliferation of cancer cells was inhibited by CMA, which suggested the androgen axis is critical for cancer growth in these mice. CONCLUSIONS: Conditional PTEN-deficient mice are useful as a preclinical model for chemoprevention studies and serve as a valuable tool for the future screening of potential chemopreventive agents.

Castration-resistant prostate cancer is an incurable heterogeneous disease that is characterized by a complex multistep process involving different cellular and biochemical changes brought on by genetic and epigenetic alterations. These changes lead to the activation or overexpression of key survival pathways that also serve as potential therapeutic targets. Despite promising preclinical results, molecular targeted therapies aimed at such signaling pathways have so far been dismal. In the present study, we used a PTEN-deficient mouse model of prostate cancer to show that plasticity in castration-resistant tumors promotes therapeutic escape. Unlike castration-naïve tumors which depend on androgen receptor and PI3K/AKT signal activation for growth and survival, castration-resistant tumors undergo phenotypic plasticity leading to increased intratumoral heterogeneity. These tumors attain highly heterogeneous phenotypes that are characterized by cancer cells relying on alternate signal transduction pathways for growth and survival, such as mitogen-activated protein kinase and janus kinase/signal transducer and activator of transcription, and losing their dependence on PI3K signaling. These features thus enabled castration-resistant tumors to become insensitive to the therapeutic effects of PI3K/AKT targeted therapy. Overall, our findings provide evidence that androgen deprivation drives phenotypic plasticity in prostate cancer cells and implicate it as a crucial contributor to therapeutic resistance in castration-resistant prostate cancer. Therefore, incorporating intratumoral heterogeneity in a dynamic tumor model as a part of preclinical efficacy determination could improve prediction for response and provide better rationale for the development of more effective therapies.

Osteopontin (OPN) expression is increased in kidneys of rats with ethylene glycol (EG) induced hyperoxaluria and calcium oxalate (CaOx) nephrolithiasis. The aim of this study is to clarify the effect of OPN knockdown by in vivo transfection of OPN siRNA on deposition of CaOx crystals in the kidneys. Hyperoxaluria was induced in 6-week-old male Sprague-Dawley rats by administering 1.5% EG in drinking water for 2 weeks. Four groups of six rats each were studied: Group A, untreated animals (tap water); Group B, administering 1.5% EG; Group C, 1.5% EG with in vivo transfection of OPN siRNA; Group D, 1.5% EG with in vivo transfection of negative control siRNA. OPN siRNA transfections were performed on day 1 and 8 by renal sub-capsular injection. Rats were killed at day 15 and kidneys were removed. Extent of crystal deposition was determined by measuring renal calcium concentrations and counting renal crystal deposits. OPN siRNA transfection resulted in significant reduction in expression of OPN mRNA as well as protein in group C compared to group B. Reduction in OPN expression was associated with significant decrease in crystal deposition in group C compared to group B. Specific suppression of OPN mRNA expression in kidneys of hyperoxaluric rats leads to a decrease in OPN production and simultaneously inhibits renal crystal deposition.

OBJECTIVE: To evaluate the effect of the Rho kinase inhibitor, hydroxyfasudil, on bladder function in a rat model of HCl-induced chemical cystitis, and to elucidate the possible mechanisms associated with its therapeutic effect. METHODS: Female Sprague-Dawley rats with HCl-induced cystitis were given hydroxyfasudil (10 mg/kg, i.p.) for 7 days. Treatment efficacy was determined by comparing bladder function and histopathology to sham and untreated control rats. Bladder function was determined by cystometric analysis. Rho kinase activity was determined by quantitative reverse transcription polymerase chain reaction and signal inhibition of downstream Ras homolog member A/Rho kinase signaling molecules by western blot and immunohistochemistry. RESULTS: Treatment with hydroxyfasudil significantly improved bladder intercontraction intervals. Rats treated with hydroxyfasudil also showed a significant reduction of histopathological features associated with cystitis. Western blot and immunohistochemistry findings showed that hydroxyfasudil inhibited downstream molecules of Rho kinase that ameliorated changes associated with HCl-induced chemical cystitis, such as inflammatory cell recruitment and smooth muscle cell proliferation. CONCLUSION: The findings from the present study suggest a promising therapeutic role for hydroxyfasudil in bladder inflammation associated with cystitis.

The heparan sulfate sulfotransferase gene family catalyzes the transfer of sulfate groups to heparan sulfate and regulates various growth factor-receptor signaling pathways. However, the involvement of this gene family in cancer biology has not been elucidated. It was demonstrated that the heparan sulfate D-glucosaminyl 6-O-sulfotransferase-2 (HS6ST2) gene is overexpressed in colorectal cancer (CRC) and its clinical significance in patients with CRC was investigated. The mRNA levels of HS6ST2 in clinical CRC samples and various cancer cell lines were assessed using a microarray analysis and quantitative RT-PCR, respectively. An immunohistochemical (IHC) analysis of the HS6ST2 protein was performed using 102 surgical specimens of CRC. The correlations between the HS6ST2 expression status and clinicopathological characteristics were then evaluated. HS6ST2 mRNA was significantly overexpressed by 37-fold in CRC samples compared to paired colonic mucosa. High levels of HS6ST2 mRNA expression were also observed in colorectal, esophageal and lung cancer cell lines. The IHC analysis demonstrated that HS6ST2 was expressed in the cytoplasmic region of CRC cells, but not in normal colonic mucosal cells. Positive staining for HS6ST2 was detected in 40 patients (39.2%). There was no significant association between the clinicopathological characteristics and HS6ST2 expression. However, positive staining for HS6ST2 was associated with a poor survival (P=0.074, log-rank test). In conclusion, HS6ST2 was found to be overexpressed in CRC and its expression tended to be a poor prognostic factor, although the correlation was not significant. These findings indicate that HS6ST2 may be a novel cancer-related marker that may provide insight into the glycobiology of CRC.

Knowledge gained from the identification of genetic and epigenetic alterations that contribute to the progression of prostate cancer in humans is now being implemented in the development of functionally relevant translational models. GEM (genetically modified mouse) models are being developed to incorporate the same molecular defects associated with human prostate cancer. Haploinsufficiency is common in prostate cancer and homozygous loss of PTEN is strongly correlated with advanced disease. In this paper, we discuss the evolution of the PTEN knockout mouse and the cooperation between PTEN and other genetic alterations in tumor development and progression. Additionally, we will outline key points that make these models key players in the development of personalized medicine, as potential tools for target and biomarker development and validation as well as models for drug discovery.

Molecular targeting agents have become formidable anticancer weapons showing much promise against refractory tumors and functional peptides and are among the more desirable of these nanobio-tools. Intracellular delivery of multiple functional peptides forms the basis for a potent, non-invasive mode of delivery, providing distinctive therapeutic advantages. We examine the growth suppression efficiency of human renal cell carcinoma (RCC) by single-peptide targeting. We simultaneously introduced p16INK4a tumor suppressor peptides by Wr-T-mediated peptide delivery. Wr-T-mediated transport of p16INK4a functional peptide into 10 RCC lines, lacking expression of the p16INK4a molecule, reversed the specific loss of p16 function, thereby drastically inhibiting tumor growth in all but 3 lines by >95% within the first 96 h. In vivo analysis using SK-RC-7 RCC xenografts in nude mice demonstrated tumor growth inhibition by the p16INK4a peptide alone, however, inoculation of Wr-T and the p16INK4a functional peptide mixture, via the heart resulted in complete tumor regression. Thus, restoration of tumor suppressor function with Wr-T peptide delivery represents a powerful approach, with mechanistic implications for the development of efficacious molecular targeting therapeutics against intractable RCC.

OBJECTIVES: Renal ischemia-reperfusion injury (IRI), leading to acute kidney injury, is a frequent complication with renal transplantation and it is associated with graft function. Its pathogenesis involves ischemia, vascular congestion and reactive oxygen metabolites. Carvedilol is an antihypertensive drug with potent anti-oxidant properties. In this study we investigated the protective effects of carvedilol in a rat renal IRI model. METHODS: Twenty-four rats were randomized into sham, untreated control and carvedilol (2 mg/kg 30 min before surgery and 12 hr after reperfusion) treatment groups and were subjected to 60 min of left renal ischemia followed by reperfusion at 24, 48, 96 and 168 hr. RESULTS: Treatment with carvedilol significantly decreased plasma creatinine levels after IRI (up to 168 hr) compared to controls (P < 0.001), suggesting an improvement in renal function. Histopathological analysis revealed decreased IRI-induced damage in kidneys from carvedilol-treated rats. A significant increase in the expression levels of Cu/Zn superoxide dismutase and reduction of 8-hydroxydeoxyguanosine and apoptosis levels (P < 0.005) suggested a protective effect after treatment with carvedilol. CONCLUSIONS: Our findings suggest that carvedilol ameliorates IRI resulting in improved renal function.

We previously reported that personalized peptide vaccine (PPV) therapy in combination with leutenizing hormone-releasing hormone (LH-RH) analog and estramustine phosphate in certain cases is safe and capable of inducing both immune responses and clinical responses for metastatic castration-resistant prostate cancer (CRPC) patients. In the present study, PPV monotherapy was given to CRPC patients. Twenty-three patients with metastatic CRPC were treated with PPV without any additional treatment modalities, including LH-RH analogs. Samples were analyzed for peptide-specific cytotoxic T-lymphocyte (CTL) precursor analysis and peptide-reactive IgG. Toxicity and immunological and clinical responses were assessed on a three-monthly basis. Seventeen patients were available for immunological and clinical evaluation. The vaccines were well tolerated, with grade 3 erythema at injection sites in only one patient. Augmentation of CTL or IgG responses to at least one of the peptides was observed in six of 17 (35%) and 15 of 17 (88%) patients tested, respectively. Among 57 peptides used, 9 and 36 peptides induced CTL and IgG responses, respectively. Delayed-type hypersensitivity reaction was observed in eight of 17 patients. More than 30% prostate-specific antigen (PSA) decline was observed in four of 17 patients. Of these, one patient achieved a complete PSA response and another patient showed a partial PSA response with profound shrinking of lymph node metastases and prostate. The overall median survival time was 24 months (range, 5-37 months). These results suggest that PPV monotherapy appears to be safe and capable of inducing peptide-specific immune responses and clinical responses in CRPC patients. This trial was registered with University Hospital Medical Information Network (UMIN) number R000003339.

Precise and objective measurements of tumor response have yet to be standardized in the mouse orthotopic bladder cancer model. In this study, we used image analysis and green fluorescent protein (GFP) to objectively measure tumor size in response to chemotherapy. KU-7 human bladder cancer cells transfected with GFP were intravesically inoculated into 8-week-old female nude mice. Fourteen days after tumor cell inoculation, the mice were assigned into a control (PBS) group or a doxorubicin (conc. 1.0 mg/ml) treatment group and received a single instillation of treatment. Fourteen days after treatment, the bladders were surgically exposed and fluorescent images were captured and later analyzed using image analysis. Bladders were processed for histological examination. Tumor incidence determined by GFP expression and histology was 100 and 80%, respectively, in the doxorubicin treatment group. A 9-fold (histology) vs. 12-fold (GFP expression) difference in tumor regression measured by tumor area (P<0.05) and a 5-fold (histology) vs. 9-fold (GFP expression) difference in tumor regression measured by the percent of tumor area in the bladder (P<0.001) were observed in the doxorubicin treatment group. Our findings suggest that using image analysis provides a precise, sensitive and objective means to measure tumor growth and treatment response in the mouse orthotopic bladder cancer model in lieu of histological methods. Consequently, the number of mice required in an experiment can be reduced since tissue samples are not needed for histology, thus making tissue samples readily available for additional assays in both a labor-effective and cost-effective manner.

The tumor suppressor gene MMAC/PTEN located on chromosome10q23.3 has dual phosphatase activity in the phosphoinositide-3-kinase signaling pathway and inhibits Akt activation, a serine-threonine kinase, which is involved in proliferative and antiapoptotic pathways. Furthermore, MMAC/PTEN is frequently inactivated in a variety of tumors including prostate cancer. In this study, we generated a new type of gene transfer drug, GelaTen, which is a microsphere of cationized gelatin hydrogels incorporating PTEN plasmid DNA. Using our previously reported radiation-resistant PC3-Bcl-2 human prostate cancer cells (PTEN deleted), we examined the efficacy of GelaTen to force the expression of PTEN in vivo to inhibit tumor growth after intratumoral injection alone or with irradiation. Combinational therapy with GelaTen and irradiation improved both the in vitro and in vivo efficacy of growth inhibition compared with GelaTen or irradiation alone. These data show that GelaTen gene therapy, enabling radiosensitization, can potentially treat prostate cancers that have MMAC/PTEN gene alterations associated with radioresistance.

INTRODUCTION: Although most vaccines target foreign infectious agents, therapeutic cancer vaccines target both well-established and metastatic tumor cells expressing tumor antigens. Active immunotherapy is intended to enhance or activate the immunosurveillance of an individual through a therapeutic vaccine. Renal cell carcinoma (RCC) is one of the most immunoresponsive cancers in humans, which in turn makes it an ideal candidate for immune based therapies. METHOD: Several types of therapeutic vaccines have been tested and applied in the clinical setting and can be divided into cell-based vaccines including direct application of inactivated autologous tumor cells, gene modified tumor cell-based, dendritic cell-based (expressing RCC derived tumor antigens), and non-cell-based vaccines. This review will examine the current status of cell-based vaccine immunotherapy and focuses on non-cell-based vaccine strategies. CONCLUSION: Recent advances in molecular targeting therapy have introduced a battery receptor tyrosine kinase (RTK) and mTOR inhibitors that provide promising treatment options, however, the tolerability of tumor vaccines and the success of clinical effectiveness in selected populations combined with recent advances in cellular therapies warrant the continued exploration of novel methods of tumor vaccine therapies in the clinical setting.

私たちが独自に開発しpreclinicalかつ免疫学的評価を可能とする去勢感受性および去勢抵抗性前立腺癌マウスモデルを用いて、PTEN欠損前立腺癌におけるアンドロゲン受容体(AR)およびPI3K/AKT経路の阻害が抗腫瘍効果、腫瘍の免疫微小環境にどの様な役割を果たしているのか、加えて抗PD-L1抗体に対する反応や骨髄由来免疫抑制細胞(MDSC)について基礎的検討を行った。AR阻害薬として第2世代のアビラテロン、AKT阻害薬としてCapivasarutibを用いて、それぞれの単独および併用療法の効果を調べた。 研究結果として、癌抑制遺伝子であるPTENの欠損により増殖シグナルpathwayのPI3K/AKTシグナル伝達が恒常的に活性化されている前立腺癌では、アビラテロンにcapivasertibを加えることで、治療効果が有意に強化された。アビラテロン単剤治療はPI3K/AKT経路が亢進するが、capivasertibを加えるとPI3K/AKT経路の亢進を抑えつつ、免疫抑制細胞の腫瘍への浸潤を抑制しM1マクロファージの増加やCD8+T細胞の活性により腫瘍縮小効果が認められた。MDSCが多く免疫抑制的な腫瘍微小環境では免疫チェックポイント阻害治療はJAK1/2阻害薬と併用することで抗腫瘍効果が得られた。 前立腺癌マウスモデルを用いた他の研究成果として、①Apalutamide治療の免疫と分子の反応について、②前立腺癌と腸内細菌について、③細胞外アデノシンの阻害とApalutamide併用療法について、2023年の日本癌学会(JCA)で報告した。（演題番号:P-2220、E-2042、E-1060、E-1039）また、2024年4月開催の米国癌学会(AACR)ではこれらのupdate結果がAcceptされ報告している。（学会発表欄参照。）

本研究の初年度は、2020年からのCOVID19感染拡大の影響を受け、加えて当病院内において大規模クラスターが複数回発生したことも大きく影響し、サンプル収集に苦慮した。昨年2022年度は、ようやくCOVID19感染拡大が落ち着き、通常の癌治療が実行できるようになったことから、IO-drug治療前後の血液サンプルが目標の20例を達成し、同時に手術による腫瘍組織サンプルもストックすることができた。血液サンプルは、血漿とPBMCとして液体窒素に保存しており、腫瘍サンプルは凍結標本（-80℃）とパラフィンブロックとして保存している。CTL誘導能についてのアッセイをいきなり行うのではなく、腫瘍微小免疫環境と免疫療法の治療効果と何かしらの密接な関連性が存在するという観点から、まず、腫瘍組織を用いた腫瘍浸潤免疫担当細胞の師匠環境に関するパイロット研究を計画した。IOベース複合免疫療法により、効果があった数症例と全く効果のなかった数症例について、パイロットスタディとして、多重IHCによる腫瘍内浸潤細胞の免疫プロファイルについて検討してみた。具体的には、手術によって得られた腎癌組織の免疫関連分子に対するMulticolarIHC（多重染色）を施行し、免疫担当細胞の免疫学的機能について細胞表面マーカーなどの発現を検討し、種々の結果を得た。結果に基づきMulticolor FCMやMass cytometerを用いた免疫プロファイリングを施行する予定である。なお、後述しているが、腫瘍微小免疫環境と治療効果に関するパイロット研究の一部の結果は、2024年4月の日本泌尿器科学会総会でポスター発表する予定である。

１．前立腺癌細胞において、L型アミノ酸トランスポーター１（LAT1）とヘテロダイマーを構成するSLC3A2/4F2hcの解析を行った。C4-2細胞をsi4F2hcで処理すると、細胞の成長、移動性、浸潤性の能力が抑制される。また、4F2hcの下流分子がSKP2であることがRNA seqによって証明された。4F2hcの高発現は無増悪生存率の独立した予後因子であった。Sci Rep. 2021 Jun 1;11(1):11478.２．AR-V7を発現するCRPC細胞であるLNCaP95を比較して、エピゲノムとトランスクリプトームの解析を行った。ChIP-seq解析で同定された399個のAR-V7標的領域のうち、377個はホルモン刺激を受けたARが共通して標的となりうる領域であり、22個はAR-V7が特異的に標的とする領域であった。AR-V7ノックダウンによって最も抑制された遺伝子としてSLC3A2/4F2hcを同定した。Transl Oncol. 2021 Jan;14(1):100915. ３．L型アミノ酸トランスポーター3（LAT3、SLC43A1）は去勢感受性前立腺癌（PC）で豊富に発現。AR のクロマチン免疫沈降法シークエンスにおいて、SLC43A1 領域への AR の結合は、ジヒドロテストステロン刺激により増加した。LAT3 をノックダウンすると、細胞増殖、遊走、浸潤が抑制され、p70S6K と 4EBP-1 のリン酸化が抑制された。多変量解析では、LAT3の高発現は無再発生存の独立した予後因子であった（ハザード比：3.24；P = 0.0018）。Cancer Sci. 2021 Sep;112(9):3871-3883.

Immune checkpoint blockade has transformed the landscape of cancer therapy but has been ineffective in patients with advanced prostate cancer (PCa). The tumor microenvironment (TME) is a major determinant of antitumor immune response. We have used a transgenic mouse of Pten-null PCa to characterize the TME. Our studies showed that myeloid-derived suppressor cells (MDSCs) were associated with PCa progression. Moreover, androgen deprivation therapy further exacerbated MDSC infiltration and was associated with disease progression in castration-resistant tumors. Targeting MDSCs by neoadjuvant blockade of JAK1/2 plus anti-PD-L1 blockade reinvigorated antitumor T cell immune response resulting in improved therapeutic efficacy. Our studies provide additional insights into the role of MDSCs in PCa. Our system provides a robust tool to further develop strategies targeting the immunosuppressive TME of advanced PCa. Our findings were presented in part at the AACR and JCA annual meetings.

We have been working on the development of new MHC Class-I restricted peptide vaccines for five independent therapeutic targets (CA9, VEGFR1, EPOR, PDL1, HIF1) and our studies have successfully resulted in two Japanese patents (#6900610, #6918333) in 2021. We are currently investigating immunological evaluations of our peptide vaccines with immune check point therapies using PBMCs from advanced RCC patients receiving IO-drugs. Most of the data such as ability of specific CTL induction are not reported in public due to patent.

We previously showed that androgen withdrawal led to increased alternatively spliced products in our originally established mouse prostate tumors. Here, we perform gene expression analysis this mouse prostate cancer model to identify candidate mRNA processing genes implicated in the progression to castration-resistant disease. Affymetrix GeneChip mouse transcriptome assay to perform comparative analysis of the transcriptomes of normal prostate tissue and PTEN-deficient castration-naïve, castration-sensitive prostate cancers. Clustering analysis revealed genes enriched with the functions involved in mRNA splicing and processing in mice with prostate tumors. Of these. We focused on NEAT1（encoding nuclear paraspeckle assembly transcript 1）and investigated anti-tumor effects using our mouse prostate cancer model. A part of the date was reported at JCA and AACR meetings.

We have been working on the development of new MHC-class-I restricted peptide vaccines for five independent therapeutic targets （CA9、VEGFR1、EPOR、PDL1、HIF1）and have identified a significant candidate a part of HLA-A2 restricted peptide vaccines (EPOR, PDL1 and HIF1). We are currently investigating their clinical relevance. Together with CA9 and VEGFR1 previously developed peptide vaccines, we will establish multi-peptide vaccination system using these five peptide vaccines.

We have previously developed a PTEN flox/PSA-Cre transgenic mouse prostate cancer model. In the current research, we focused on p53 (Trp53) to establish a more aggressive metastatic prostate cancer model. Using the same gene engineering method, we established a PSA-conditional PTEN/p53 double knockout (PTEN/p53 DKO) mouse prostate cancer model. Mice with DKO homo-deletion develop an aggressive phenotype characterized by a higher incidence of metastasis, including multiple metastases to lungs, liver, lymph nodes and other distant organs, and decreased survival (median overall survival, 55 weeks of the age), enabling us to use the PTEN/p53 DKO mouse model to evaluate the therapeutic efficacy in a ramdomised controlled studies with similar end points of PFS and OS to a human phase-3 trial. These findings demonstrate the usefulness of the PTEN/p53 DKO mouse prostate cancer model for the preclinical development of novel treatment strategies for prostate cancer.

We have been working on the development of new MHC-class-I restricted peptide vaccines for five independent therapeutic targets and have identified a significant candidate EPOR, PDL1 and HIF1. We made the application of patents for EPOR and PDL1 peptide vaccine and are preparing the application for HIF1. Together with CA9 and VEGFR1 previously developed peptide vaccines, we established multi-peptide vaccination system using these five peptide vaccines.

e conducted this study to research the effect of selenium intake on prevention of the prostate cancer using a mouse model. As a result, no significant difference was detected in the occurrence of prostate cancer among three groups of mice that had been fed with the control or low- or high-concentration selenium-containing feeds.

e have been working on the development of new MHC-class-I restricted peptide vaccines for five independent therapeutic targets and have identified a significant candidate EPORxx. We are preparing the application of a patent for this particular peptide vaccine. We also carried out phase-I/II clinical study with VEGFR1 peptide vaccines for 18 patients with disseminated renal cell carcinoma, and showed the safty and efficacy of the vaccination treatment.

To better understand the disease process of prostate cancer, we have developed a prostate-specific conditional knockout mouse model that targets the PTEN tumor suppressor gene. Our model is based on PSA-Cre recombinase driven inactivation of Pten to alter PI3K/Akt/mTOR signaling specific to the prostate, resulting in a stage-specific development and progression of cancer that mimics humans recapitulating various stages of disease progression ranging from precancerous PIN lesions to castration resistant prostate cancer. We performed several experiments that demonstrate the versatility and usefulness of this model for validation of preclinical targeted intervention, biomarker discovery (leptin, lumican and HOXA10) and characterizing lifestyle behavior effects on cancer progression.

We found for the first time that a novel DNA repair protein, hABH-8 promotes survival of human urothelial carcinoma cells through up-regulating generation of reactive oxygen species, moreover, the expression of hABH-8 is a useful marker to predict clinical development of urinary bladder cancer.

我々はPTENという癌抑制伝子を中心に前立腺癌の研究を重ねてきた。今回樹立したPTEN遺伝子改変マウスは、前立腺における多段階発癌と徐睾術によりホルモン抵抗性前立腺癌-移行する前立腺癌発症モデルである。このモデルを中心に前立腺癌の発癌機序解明およびホルモン抵抗性獲得の分子機構の網羅的な解析を行った。また、選択的Cox2阻害薬(Meloxicam)による癌予防研究、さらに新規合成したペプチドによる創薬の有用性をこのモデルを用いて検証した。