Prostate Cancer Samples Research Articles

Abstract 1895: Molecular characterization of prostate cancer between Hispanic American and Non-Hispanic Whites: Implications for cancer ethnic health disparities

Abstract Background: Although there is increased awareness leading to early detection and prevention, Hispanic American (HA) men with prostate cancer (PC) continue to have greater mortality rates compared to their Non-Hispanic White (NHW) counterparts. Moreover, HA men with PC are more likely to have more advanced disease compared to NHW men. Here, we characterized the molecular and immune differences in HA and NHW tumors and their association with PC ethnic disparity. Methods: 88 PC samples (HA=34, NHW=54) obtained from treatment-naive metastatic hormone-sensitive PC (mHSPC) were analyzed by next-generation sequencing (592, NextSeq; WES, NovaSeq), Whole Transcriptome Sequencing (WTS; NovaSeq) (Caris Life Sciences, Phoenix, AZ). AR signature and NEPC score were calculated based on the expression level of previously defined genes (Hieronymus et al. 2006, Beltran et al. 2016). Medical record was reviewed in a deidentified fashion for clinal features. Statistical significance was determined using chi-square and Mann-Whitney U (p<0.05). Results: HA patients with PC had higher level of PSA (111.5 vs 52.6 ng/ml, p=0.12) and stage (T4: 41% vs 14% p=0.01, M1c: 41% vs 16% p=0.04) but no significant difference in frequency of Gleason score > 4 (79% vs 73%, p=0.61) or stage N1 (69% vs 61%, p=0.85) compared to NHW. HA PC had a significantly higher frequency of TMPRSS2-fusion (46.4% vs 20.0%, p=0.04) compared to NHW PC. By Gene Set Enrichment Analysis, HA PC had enrichment of KRAS signaling (NES: 1.44, FDR=0.02), Hedgehog signaling (NES: 1.45, FDR=0.04), NOTCH signaling (NES: 1.41, FDR=0.07), Hypoxia (NES: 1.38, FDR=0.10) and IL2-STAT5 signaling (NES: 1.35, FDR=0.10) pathways compared to NHW tumors. There was no difference in median Androgen Receptor signature (p=0.78) or Neuroendocrine Prostate Cancer (NEPC) score (p=0.79). Also, no significant difference in AR positivity by IHC (100% vs 95.7%) between HA and NHW PC tumors (p=0.51). HA PC had significantly higher expression of stem cell markers ALDH1A1 (2.1-fold), ALDH1A2 (3-fold), and PROM1 (1.6-fold) and immunoinhibitory genes PDCD1LG2 (1.68-fold) and FOXP3 (1.45-fold) compared to NHW tumors (all p<0.05). Additionally, HA tumors had increased infiltration of M1 Macrophages (0.72% vs 0%) and NK cells (4.84% vs 3.55%, all p<0.05), and increased T-cell inflamed score (44.0 vs -49.0, p=0.14) compared to NHW. Conclusion: Our data suggest that HA mHSPC is associated with higher levels of PSA, stage, TMPRSS2-fusions, stemness marker expression, immunoinhibitory gene expression, and increased M1 Macrophage and NK cell infiltration. Together, these findings suggest a crucial role of differential molecular and tumor immune microenvironment in PC ethnic disparity. A better understanding of these differences with additional research may help in designing the approaches for reducing the ethnic disparities gaps in PC patients. Citation Format: Alejandro Recio-Boiles, Sachin Kumar Deshmukh, Juan Chipollini, Ken Batai, Sharon Wu, Joanne Xiu, Alex Farrell, Milan Radovich, Elisabeth Heath, Rana McKay, Chadi Nabhan. Molecular characterization of prostate cancer between Hispanic American and Non-Hispanic Whites: Implications for cancer ethnic health disparities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1895.

Abstract 6542: Detection of androgen receptor splice variants from clinical sequencing

Abstract Androgen receptor (AR) splice variants (AR-Vs) have been widely studied on its important role in prostate cancer (PC) progression. In particular, AR-Vs lacking ligand binding domains, such as AR splice variant 7 (AR-v7) that links exon 3 and cryptic exon 3 or AR variant that losses exons 5 to 7 (ARv567es), have been demonstrated as one of the resistant mechanisms to androgen deprivation therapy in PC. Despite its clinical importance, the current algorithms to detect fusions such as TopHat-Fusion have limitation to detect intra-chromosomal rearrangements including AR-Vs. In this respect, we propose a novel approach to identify AR-Vs from targeted RNA sequencing (RNA-seq) dataset. In short, our two-step approach first gathers soft-clipped or divided reads that are adjacent to the splicing sites of AR-Vs and then yields the number of splitting reads that support the existence of AR-Vs. Next, the algorithm selects the paired-end reads whose one side and the other side are mapped to the preceding and following exons, respectively. The final number of spanning reads are calculated following to the removal of low-quality reads. We validated the proposed approach using two large-scale, independent RNA-seq datasets of PC samples: 34 samples from Seoul National University Hospital (SNUH) and 558 samples from The Cancer Genome Atlas (TCGA) dataset. Overall, our approach successfully identified samples with putative AR-Vs, including AR-v7 and ARv567es. In addition, our approach successfully detected AR-v7 with reliable number of supporting reads, from the RNA-seq dataset of AR-v7-expressing cell line. Finally, statistical analyses of 34 SNUH PC patients suggested potential detection threshold in clinical sequencing settings (at least 10 split reads and 1% proportion). In the SNUH dataset, The AR-v7 positive group, which included 6 patients (17.1%) with values above the threshold, had higher AR-v7 expression levels than the negative group (p=4.8E-04). The similar pattern was also found in the analysis of TCGA dataset. Owing to its flexibility, we also confirmed that the developed approach can be used to detection of other AR-Vs, including AR-v3 and ARv567es. We expect that the further in-depth analyses including larger samples and clinical outcomes can discover clinical applicability of AR-Vs. Citation Format: Suhyun Hwangbo, Sungyoung Lee, Sheehyun Kim, Hongseok Yun. Detection of androgen receptor splice variants from clinical sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6542.

YY1 complex in M2 macrophage promotes prostate cancer progression by upregulating IL-6

BackgroundTumor-associated macrophages are mainly polarized into the M2 phenotype, remodeling the tumor microenvironment and promoting tumor progression by secreting various cytokines.MethodsTissue microarray consisting of prostate cancer (PCa), normal prostate, and...

MP20-01 PROTEIN KINASE D1 (PrKD) PROTECTS AGAINST DNA DAMAGE BY INCREASING Α-CATENIN LEVELS THROUGH PUTATIVE SERINE681 AND 685 PHOSPHORYLATION OF CYCLIN DEPENDENT KINASE 12 (CDK12) IN PROSTATE CANCER (PC)

You have accessJournal of UrologyCME1 Apr 2023MP20-01 PROTEIN KINASE D1 (PrKD) PROTECTS AGAINST DNA DAMAGE BY INCREASING Α-CATENIN LEVELS THROUGH PUTATIVE SERINE681 AND 685 PHOSPHORYLATION OF CYCLIN DEPENDENT KINASE 12 (CDK12) IN PROSTATE CANCER (PC) Sanjeev Shukla, Teruko Osumi, Mohammed Al-Toubat, Carlos Riveros, Allison H. Feibus, Ahmed El-shafie, Adam M. Kase, John A. Copland, Joachim L. Petit, Nathalie Meurice, Justyna Gleba, Jonathan Chardon-Robles, and K. C. Balaji Sanjeev ShuklaSanjeev Shukla More articles by this author , Teruko OsumiTeruko Osumi More articles by this author , Mohammed Al-ToubatMohammed Al-Toubat More articles by this author , Carlos RiverosCarlos Riveros More articles by this author , Allison H. FeibusAllison H. Feibus More articles by this author , Ahmed El-shafieAhmed El-shafie More articles by this author , Adam M. KaseAdam M. Kase More articles by this author , John A. CoplandJohn A. Copland More articles by this author , Joachim L. PetitJoachim L. Petit More articles by this author , Nathalie MeuriceNathalie Meurice More articles by this author , Justyna GlebaJustyna Gleba More articles by this author , Jonathan Chardon-RoblesJonathan Chardon-Robles More articles by this author , and K. C. BalajiK. C. Balaji More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003245.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: PrKD is protective of DNA damage in PC and loss of PrKD leading to increased genomic instability is a novel potential mechanism. CDK12 mutated PC is now recognized as a distinct aggressive variant associated with genomic instability. We explored whether PrKD influences DNA damage through CDK12. METHODS: The DNA damage and protein levels studied by COMET assay and western blot respectively and validated the findings in human PC samples by querying cBioPortal gene expression. RESULTS: PrKD abrogated etoposide induced DNA damage in castration insensitive C4-2 PC cells. PrKD is a membrane bound protein that phosphorylates proteins in cell adherens junction including β-catenin. As PrKD is the only known kinase to phosphorylate T120 in β-catenin, mutation of T120 leads to nuclear translocation of transcriptionally active β-catenin playing a role in DNA damage, uncouples the binding of β- to α-catenin, which translocates to the nucleus and influences β-catenin. PrKD increased the expression of α-catenin, which was attenuated by CDK12 wild type and double non-phosphorylated mutants of PrKD putative phosphorylation sites; serine (s) 681 and 685 but not as much by s681 mutant. PrKD suppressed the substrate phosphorylation of γH2AX s139 by CDK12 s681 and s681/s685 non-phosphorylated mutant compared to wild type, which links PrKD substrate phosphorylation of CDK12 to DNA damage. Query of cBioPortal for concurrent PrKD1 and CDK12 mutations in PC with characteristic gene signature of DNA damage repair (DDR) revealed the highest concordance of PrKD1 and CDK12 mutations in patients with BRAC2 mutations and the DDR genes expression were not significantly different between patients with PrKD1 and CDK12 mutated patient except BRAC1 expression (rarely mutated in PC) suggesting that PrKD1 and CDK12 could be involved in the same signaling pathway (Figure 1). CONCLUSIONS: The study provides a validated mechanistic basis for the novel protective role of PrKD in DNA damage, which has potential implications in PC therapeutics linked to DNA damage. Source of Funding: none © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e275 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sanjeev Shukla More articles by this author Teruko Osumi More articles by this author Mohammed Al-Toubat More articles by this author Carlos Riveros More articles by this author Allison H. Feibus More articles by this author Ahmed El-shafie More articles by this author Adam M. Kase More articles by this author John A. Copland More articles by this author Joachim L. Petit More articles by this author Nathalie Meurice More articles by this author Justyna Gleba More articles by this author Jonathan Chardon-Robles More articles by this author K. C. Balaji More articles by this author Expand All Advertisement PDF downloadLoading ...

Targeting the chromatin effector Pygo2 promotes cytotoxic T cell responses and overcomes immunotherapy resistance in prostate cancer.

The noninflamed microenvironment in prostate cancer represents a barrier to immunotherapy. Genetic alterations underlying cancer cell-intrinsic oncogenic signaling are increasingly appreciated for their role in shaping the immune landscape. Recently, we identified Pygopus 2 (PYGO2) as the driver oncogene for the amplicon at 1q21.3 in prostate cancer. Here, using transgenic mouse models of metastatic prostate adenocarcinoma, we found that Pygo2 deletion decelerated tumor progression, diminished metastases, and extended survival. Pygo2 loss augmented the activation and infiltration of cytotoxic T lymphocytes (CTLs) and sensitized tumor cells to T cell killing. Mechanistically, Pygo2 orchestrated a p53/Sp1/Kit/Ido1 signaling network to foster a microenvironment hostile to CTLs. Genetic or pharmacological inhibition of Pygo2 enhanced the antitumor efficacy of immunotherapies using immune checkpoint blockade (ICB), adoptive cell transfer, or agents inhibiting myeloid-derived suppressor cells. In human prostate cancer samples, Pygo2 expression was inversely correlated with the infiltration of CD8+ T cells. Analysis of the ICB clinical data showed association between high PYGO2 level and worse outcome. Together, our results highlight a potential path to improve immunotherapy using Pygo2-targeted therapy for advanced prostate cancer.

A novel lysosome-related gene signature coupled with gleason score for prognosis prediction in prostate cancer.

Background: Prostate cancer (PCa) is highly heterogeneous, which makes it difficult to precisely distinguish the clinical stages and histological grades of tumor lesions, thereby leading to large amounts of under- and over-treatment. Thus, we expect the development of novel prediction approaches for the prevention of inadequate therapies. The emerging evidence demonstrates the pivotal role of lysosome-related mechanisms in the prognosis of PCa. In this study, we aimed to identify a lysosome-related prognostic predictor in PCa for future therapies. Methods: The PCa samples involved in this study were gathered from The Cancer Genome Atlas database (TCGA) (n = 552) and cBioPortal database (n = 82). During screening, we categorized PCa patients into two immune groups based on median ssGSEA scores. Then, the Gleason score and lysosome-related genes were included and screened out by using a univariate Cox regression analysis and the least absolute shrinkage and selection operation (LASSO) analysis. Following further analysis, the probability of progression free interval (PFI) was modeled by using unadjusted Kaplan-Meier estimation curves and a multivariable Cox regression analysis. A receiver operating characteristic (ROC) curve, nomogram and calibration curve were used to examine the predictive value of this model in discriminating progression events from non-events. The model was trained and repeatedly validated by creating a training set (n = 400), an internal validation set (n = 100) and an external validation (n = 82) from the cohort. Results: Following grouping by ssGSEA score, the Gleason score and two LRGs-neutrophil cytosolic factor 1 (NCF1) and gamma-interferon-inducible lysosomal thiol reductase (IFI30)-were screened out to differentiate patients with or without progression (1-year AUC = 0.787; 3-year AUC = 0.798; 5-year AUC = 0.772; 10-year AUC = 0.832). Patients with a higher risk showed poorer outcomes (p < 0.0001) and a higher cumulative hazard (p < 0.0001). Besides this, our risk model combined LRGs with the Gleason score and presented a more accurate prediction of PCa prognosis than the Gleason score alone. In three validation sets, our model still achieved high prediction rates. Conclusion: In conclusion, this novel lysosome-related gene signature, coupled with the Gleason score, works well in PCa for prognosis prediction.

ZNF750: A Novel Prognostic Biomarker in Metastatic Prostate Cancer

Prostate cancer is the most frequently diagnosed cancer and the fifth leading cause of cancer death among men in 2020. The clinical decision making for prostate cancer patients is based on the stratification of the patients according to both clinical and pathological parameters such as Gleason score and prostate-specific antigen levels. However, these tools still do not adequately predict patient outcome. The aim of this study was to investigate whether ZNF750 could have a role in better stratifying patients, identifying those with a higher risk of metastasis and with the poorest prognosis. The data reported here revealed that ZNF750 protein levels are reduced in human prostate cancer samples, and this reduction is even higher in metastatic samples. Interestingly, nuclear positivity is significantly reduced in patients with metastatic prostate cancer, regardless of both Gleason score and grade group. More importantly, the bioinformatics analysis indicates that ZNF750 expression is positively correlated with better prognosis. Overall, our findings suggest that nuclear expression of ZNF750 may be a reliable prognostic biomarker for metastatic prostate cancer, which lays the foundation for the development of new biological therapies.

Potential clinical application of the cancer antigen CA‑62 for differential diagnosis of prostate cancer and benign prostatic hyperplasia at the elevated prostate‑specific antigen

Purpose of the study. Evaluation of the diagnostic characteristics of the CA‑62 marker for epithelial carcinomas for detecting early‑stage prostate cancer in a double‑blind clinical study. This study is also focused on the possibility of using the CA‑62 antigen as an auxiliary tool for decision‑making in prostate cancer diagnosis.Patients and methods. A blinded clinical study was conducted on 325 clinically verified blood serum samples. This includes 144 prostate cancer samples, 79 generally healthy volunteers‑men and 102 samples from patients with benign prostatic hyperplasia (BPH). Quantitative determination of the total and free prostate specific antigen (PSA) levels, as well as the CA‑62 marker of serum samples was performed using the electrochemiluminescent immunoassay ECLIA Elecsys Total and Free PSA (COBAS, Roche Diagnostics GmbH, Germany, EU) and the chemiluminescent immunoassay CLIA‑CA‑62 (JVS Diagnostics LLC, Moscow, RF).Results. A comparison of the CA‑62 level with the results for total and free PSA, as well as other diagnostic methods (PCA3, PHI) for the analysis of the BPH and prostate cancer groups was performed. The results show that the CA‑62 marker has the highest PPV (94.4 %) and NPV (93.1 %). This may increase the reliability of the decision related to the presence of PC and be used by doctors as an argument as an argument for a prostate biopsy referral. It has been demonstrated that using the novel cancer marker CA‑62 makes it possible to detect up to 90 % of the early‑stage prostate cancer with 97.2 % specificity (AUC = 0.969).Conclusion. Using the CA‑62 marker as an auxiliary diagnostic method within the PSA “grey zone” (from 2.5 to 10 ng/ml) made it possible to significantly increase the accuracy of detecting the PC early stages at biopsy up to 93.1 %. It will help the doctors to effectively differentiate between prostate cancer and benign prostatic hyperplasia.

Identification of cancer-associated fibroblasts subtypes in prostate cancer.

Cancer-associated fibroblasts (CAFs) are one of the most abundant cell types in tumor microenvironment. However, the phenotypic and functional heterogeneities among CAFs have not been sufficiently investigated in prostate cancer. We obtained and analyzed the single-cell RNA-sequencing data from 26 hormone-sensitive prostate cancer samples and 8 castration-resistant prostate cancer samples, along with the analysis of bulk-sequencing datasets. Furthermore, we performed multicolor immunofluorescence staining to verify the findings from the data analysis. We identified two major CAFs subtypes with distinct molecular characteristics and biological functions in prostate cancer microenvironment, namely αSMA+ CAV1+ CAFs-C0 and FN1+ FAP+ CAFs-C1. Another single-cell RNA-sequencing dataset containing 7 bone metastatic prostate cancer samples demonstrated that osteoblasts in the bone metastatic lesions comprised two subtypes with molecular characteristics and biological functions similar to CAFs-C0 and CAFs-C1 in the primary tumor sites. In addition, we discovered a transcriptional factor regulatory network depending on CAFs-C1. CAFs-C1, but not CAFs-C0, was associated with castration resistance and poor prognosis. We also found that CAFs-C1 signature was involved in treatment resistance to immune checkpoint inhibitors. In summary, our results identified the presence of heterogeneous CAFs subtypes in prostate cancer microenvironment and the potential of specific CAFs subtype as therapeutic target for castration-resistant prostate cancer.

Development and validation of a tumor immune cell infiltration-related gene signature for recurrence prediction by weighted gene co-expression network analysis in prostate cancer.

Introduction: Prostate cancer (PCa) is the second most common malignancy in men. Despite multidisciplinary treatments, patients with PCa continue to experience poor prognoses and high rates of tumor recurrence. Recent studies have shown that tumor-infiltrating immune cells (TIICs) are associated with PCa tumorigenesis. Methods: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets were used to derive multi-omics data for prostate adenocarcinoma (PRAD) samples. The CIBERSORT algorithm was used to calculate the landscape of TIICs. Weighted gene co-expression network analysis (WGCNA) was performed to determine the candidate module most significantly associated with TIICs. LASSO Cox regression was applied to screen a minimal set of genes and construct a TIIC-related prognostic gene signature for PCa. Then, 78 PCa samples with CIBERSORT output p-values of less than 0.05 were selected for analysis. WGCNA identified 13 modules, and the MEblue module with the most significant enrichment result was selected. A total of 1143 candidate genes were cross-examined between the MEblue module and active dendritic cell-related genes. Results: According to LASSO Cox regression analysis, a risk model was constructed with six genes (STX4, UBE2S, EMC6, EMD, NUCB1 and GCAT), which exhibited strong correlations with clinicopathological variables, tumor microenvironment context, antitumor therapies, and tumor mutation burden (TMB) in TCGA-PRAD. Further validation showed that the UBE2S had the highest expression level among the six genes in five different PCa cell lines. Discussion: In conclusion, our risk-score model contributes to better predicting PCa patient prognosis and understanding the underlying mechanisms of immune responses and antitumor therapies in PCa.

Inceptor correlates with markers of prostate cancer progression and modulates insulin/IGF1 signaling and cancer cell migration

ObjectiveThe insulin/insulin-like growth factor 1 (IGF1) pathway is emerging as a crucial component of prostate cancer progression. Therefore, we investigated the role of the novel insulin/IGF1 signaling modulator inceptor in prostate cancer. MethodsWe analyzed the expression of inceptor in human samples of benign prostate epithelium and prostate cancer. Further, we performed signaling and functional assays using prostate cancer cell lines. ResultsWe found that inceptor was expressed in human benign and malignant prostate tissue and its expression positively correlated with various genes of interest, including genes involved in androgen signaling. In vitro, total levels of inceptor were increased upon androgen deprivation and correlated with high levels of androgen receptor in the nucleus. Inceptor overexpression was associated with increased cell migration, altered IGF1R trafficking and higher IGF1R activation. ConclusionsOur in vitro results showed that inceptor expression was associated with androgen status, increased migration, and IGF1R signaling. In human samples, inceptor expression was significantly correlated with markers of prostate cancer progression. Taken together, these data provide a basis for investigation of inceptor in the context of prostate cancer.

Opposite changes in the expression of clathrin and caveolin-1 in normal and cancerous human prostate tissue: putative clathrin-mediated recycling of EGFR

Endocytosis, an important macromolecule uptake process in cells, is known to be dysregulated in cancer. Clathrin and caveolin-1 proteins play a major role in receptor-mediated endocytosis. We have used a quantitative, unbiased and semi-automated method to measure in situ protein expression of clathrin and caveolin-1 in cancerous and paired normal (cancer adjacent, non-cancerous) human prostate tissue. There was a significant (p < 0.0001) increase in the expression of clathrin in prostate cancer samples (N = 29, n = 91) compared to normal tissue (N = 29, n = 67) (N = number of patients, n = number of cores in tissue arrays). Conversely, there was a significant (p < 0.0001) decrease in expression of caveolin-1 in prostate cancer tissue compared to normal prostate tissue. The opposite change in expression of the two proteins was highly correlated to increasing cancer aggressiveness. There was also a concurrent increase in the expression of epidermal growth factor receptor (EGFR), a key receptor in carcinogenesis, with clathrin in prostate cancer tissue, indicating recycling of EGFR through clathrin-mediated endocytosis (CME). These results indicate that in prostate cancer, caveolin-1-mediated endocytosis (CavME) may be acting as a brake and increase in CME may facilitate tumorigenicity and aggressiveness of prostate cancer through recycling of EGFR. Changes in the expression of these proteins can also potentially be used as a biomarker for prostate cancer to aid in diagnosis and prognosis and clinical decision-making.

Implementation of BRCA mutations testing in formalin-fixed paraffin-embedded (FFPE) samples of different cancer types.

BRCA1 and BRCA2 are onco-suppressor genes involved in the DNA repair mechanism. The presence of BRCA1/2 mutations confers a higher risk of developing several cancer types. To date, the FDA approved various PARP inhibitors to treat selected BRCA1/2 mutated oncologic patients. At first, PARP inhibitors were approved for patients with ovarian and breast cancers, and subsequently for metastatic pancreatic adenocarcinoma and metastatic castration-resistant prostate cancer after the treatment with chemotherapy. The current guidelines for BRCA testing are very heterogeneous between the different types of tumors regarding the diagnostic algorithm and the type of sample to analyze, such as the blood for the germline mutations and the tumoral tissue for the somatic mutations. Few data have currently been described regarding the detection of BRCA1/2 somatic mutations in formalin-fixed paraffin-embedded (FFPE) samples. In this review, we propose an overview of the BRCA mutations in FFPE samples of several cancers, including breast, ovarian, fallopian tube, primary peritoneal, prostate, and pancreatic cancer. We summarize the types and the frequency of BRCA mutations, the guidelines approved for the test, the molecular assays used for the detection and the PARP inhibitors approved for each tumor type.

BHLHE22 drives the immunosuppressive bone tumor microenvironment and associated bone metastasis in prostate cancer.

The molecular characteristics of prostate cancer (PCa) cells and the immunosuppressive bone tumor microenvironment (TME) contribute to the limitations of immune checkpoint therapy (ICT). Identifying subgroups of patients with PCa for ICT remains a challenge. Herein, we report that basic helix-loop-helix family member e22 (BHLHE22) is upregulated in bone metastatic PCa and drives an immunosuppressive bone TME. In this study, the function of BHLHE22 in PCa bone metastases was clarified. We performed immunohistochemical (IHC) staining of primary and bone metastatic PCa samples, and assessed the ability to promote bone metastasis in vivo and in vitro. Then, the role of BHLHE22 in bone TME was determined by immunofluorescence (IF), flow cytometry, and bioinformatic analyses. RNA sequencing, cytokine array, western blotting, IF, IHC, and flow cytometry were used to identify the key mediators. Subsequently, the role of BHLHE22 in gene regulation was confirmed using luciferase reporter, chromatin immunoprecipitation assay, DNA pulldown, co-immunoprecipitation, and animal experiments. Xenograft bone metastasis mouse models were used to assess whether the strategy of immunosuppressive neutrophils and monocytes neutralization by targeting protein arginine methyltransferase 5 (PRMT5)/colony stimulating factor 2 (CSF2) could improve the efficacy of ICT. Animals were randomly assigned to treatment or control groups. Moreover, we performed IHC and correlation analyses to identify whether BHLHE22 could act as a potential biomarker for ICT combination therapies in bone metastatic PCa. Tumorous BHLHE22 mediates the high expression of CSF2, resulting in the infiltration of immunosuppressive neutrophils and monocytes and a prolonged immunocompromised T-cell status. Mechanistically, BHLHE22 binds to the CSF2 promoter and recruits PRMT5, forming a transcriptional complex. PRMT5 epigenetically activates CSF2 expression. In a tumor-bearing mouse model, ICT resistance of Bhlhe22+ tumors could be overcome by inhibition of Csf2 and Prmt5. These results reveal the immunosuppressive mechanism of tumorous BHLHE22 and provide a potential ICT combination therapy for patients with BHLHE22+ PCa.

Differential expression of the androgen receptor gene is correlated with CAG polymorphic repeats in patients with prostate cancer

Prostate cancer (PCa) is one of the most common types of cancer in men. The aetiology of the disease is not well established, but it has been related to one of the main pathways of regulation of prostate proliferation, mediated by androgens. The androgen receptor (AR) gene encodes the androgen-receptor protein, which functions as a transactivation factor for steroid hormones. It has been proposed that the AR gene transcription levels are mediated by short tandem repeats corresponding to the CAG sequence. However, there are conflicting results in this relationship. We evaluated the expression levels of the AR gene and identified the number of CAG repeats (CAGn) in the Mexican population, establishing the relationship between expression levels and increase in the number of CAG repeats. We evaluated the expression levels of AR in tissue samples of PCa and benign prostate disease, such as benign prostatic hyperplasia, or prostatitis, to determine the difference in their expression levels. Our results showed a statistically insignificant underexpression of 0.64-fold decrease in AR levels of PCa patients compared to benign prostate disease patients (P = 0.623) and suggest that the number of CAGn was correlated with the relative expression of the AR gene (P = 0.009) and this correlation was positive, moderate, and proportional (ρ = 0.467) and no correlation was found between CAGn with other clinical features.

Molecular Insight into Drug Resistance Mechanism Conferred by Aberrant PIK3CD Splice Variant in African American Prostate Cancer.

Targeting PI3Kδ has emerged as a promising therapy for hematologic and non-hematologic malignancies. Previously, we identified an oncogenic splice variant, PIK3CD-S, conferring Idelalisib resistance in African American (AA) prostate cancer (PCa). In the current study, we employed a comprehensive analysis combining molecular biology, biochemistry, histology, in silico simulation, and in vitro functional assays to investigate the PIK3CD-S expression profiles in PCa samples and to elucidate the drug resistance mechanism mediated by PI3Kδ-S (encoded by PIK3CD-S). The immunohistochemistry, RT-PCR, and Western blot assays first confirmed that PI3Kδ-S is highly expressed in AA PCa. Compared with PCa expressing the full-length PI3Kδ-L, PCa expressing PI3Kδ-S exhibits enhanced drug resistance properties, including a higher cell viability, more antiapoptotic and invasive capacities, and constitutively activated PI3K/AKT signaling, in the presence of PI3Kδ/PI3K inhibitors (Idelalisib, Seletalisib, Wortmannin, and Dactolisib). Molecular docking, ATP-competitive assays, and PI3 kinase assays have further indicated a drastically reduced affinity of PI3Kδ inhibitors with PI3Kδ-S vs. PI3Kδ-L, attributed to the lack of core binding residues in the PI3Kδ-S catalytic domain. Additionally, SRSF2 has been identified as a critical splicing factor mediating exon 20 skipping in PIK3CD pre-mRNA. The inhibition of the SRSF2 activity by SRPIN340 successfully sensitizes AA PCa cells to PI3Kδ inhibitors, suggesting a novel therapeutic option for Idelalisib-resistant tumors.

Heterogeneity of canonical prostate cancer markers across lesions in metastatic castration-resistant prostate cancer.

219 Background: Metastatic castration-resistant prostate cancers (mCRPC) show a diversity of clinical responses and phenotypes, suggesting molecular heterogeneity. Understanding molecular phenotypes is critical for patient stratification and selection of therapeutic targets. Treatment with androgen receptor (AR) pathway inhibitors are thought to drive AR-negative disease and the emergence of neuroendocrine lineages. There are several emerging biomarkers for mCRPC, including novel targets, such as PSMA and STEAP1, and markers of neuroendocrine and aggressive disease, such as INSM1, DLL3, and loss of p53, RB1 and PTEN. Our understanding of the co-expression of such biomarkers across multiple metastatic sites is currently limited. This study aimed to determine biomarker expression in multiple anatomical sites within individual mCRPC patients. Methods: Through the rapid-autopsy CASCADE program at the Peter MacCallum Cancer Centre, tissue was obtained from 5-14 tumor sites from 12 individual mCRPC patients yielding samples from a total of 110 tumor sites (8 primary and 102 metastatic). Ten patients were diagnosed with prostate adenocarcinoma (89 sites), and 2 patients with neuroendocrine histopathology in all sites (21 sites). Tissue was stained for AR, PSMA, STEAP1, INSM1, DLL3 p53, RB1 and PTEN by immunohistochemistry (IHC). Serial sections were reviewed and scored by a pathologist. IHC results were corroborated with genetic information derived from DNA sequencing. Results: In the adenocarcinoma cohort, on average 77% of sites of individual patients had AR expression, suggesting intra-patient heterogeneity. Co-expression of AR and PSMA was common (55/89 sites), but 6/10 adenocarcinoma patients had 1 to 6 PSMA+AR- lesions. Co-expression of PSMA and STEAP1 was also common in adenocarcinoma patients (60/89 sites), although 8/10 patients had 1 to 2 PSMA-STEAP1+ lesions, and 7 patients had 1 to 3 PSMA+STEAP1- lesions. Expression of INSM1 and DLL3 was mostly seen in the 2 patients (20/21 sites) with neuroendocrine prostate cancer. In contrast, only 2 INSM1+DLL3+ tumor sites in liver and 1 INSM1-DLL3+ prostate cancer sample were detected in the adenocarcinoma cohort. Of the 110 sites, p53 loss was observed in 9, RB1 loss in 30 and PTEN loss in 25 sites. Of these, 8/9, 14/30 and 8/25 occurred in INSM1+DLL3+ sites, suggesting that loss of these markers does not always correlate with INSM1 and DLL3 expression. Conclusions: While AR, PSMA and STEAP1 expression are frequently detected in a single site of disease, this co-expression is not consistent across all sites. In this dataset, INSM1 and DLL3 expression was almost exclusively confined to neuroendocrine prostate cancer. Loss of RB1 and PTEN often occurs without INSM1 and DLL3 expression. Understanding differential biomarker expression in mCRPC may guide future targeted treatments and warrants further research.

Development of machine learning–powered models for prostate cancer HRD prediction.

206 Background: In prostate cancer, homologous recombination deficiency (HRD) is associated with poor prognosis, and sensitivity to DNA damaging agents and DNA damage repair (DDR) inhibitors. As new classes of DDR inhibitors become available, identifying patients with HRD will be critical for treatment selection. Here, we present machine learning (ML)-based models trained to predict HRD status directly from hematoxylin and eosin (H&amp;E) whole slide images (WSI). Methods: ML models were trained to predict and segment cells and tissue regions within the tumor microenvironment (TME) using annotated (N=91,021 annotations) WSI of H&amp;E-stained resections from the cancer genome atlas prostate adenocarcinoma (TCGA PRAD) dataset (N=401) and needle core biopsies from a proprietary dataset (N=1,000). Quantified Human Interpretable Features (HIFs) that describe the TME composition were extracted. Three models were trained to predict HRD status using 373 WSI with known HRD score (TCGA PRAD; train N=259, validation N=76, and test N=38). Two models used input from the TME model: An HIF multivariate logistic regression model, and a graph neural network (GNN) where predictions are based on the complex spatial relationships within the TME. An end-to-end (E2E) multiple instance learning model predicted directly from the WSI. Two cutoffs for HRD were defined using Gaussian Mixture Models, resulting in 99 WSI (train N=72, validation N=18, and test N=9) positive for the Genomic Instability (&gt;16 events) cutoff, and 58 WSI (train N=44, validation N=10, test N=4) positive for the Genomic Instability (&gt;22 events) cutoff. An independent validation set of 45 biopsies and 16 resections from a biobank of metastatic castration resistant prostate cancer with HRD status determined by whole-exome sequencing was compared to ML model H&amp;E-based HRD prediction. Results: In the TCGA test set of resection samples, all three models moderately or strongly predicted HRD status, with the HIF model showing the best performance (AUROC 0.87, sensitivity 0.88, specificity 0.62). The same HIF model performed equally well (AUROC 0.85, Sensitivity 0.93, specificity 0.67) in the resection samples from the independent validation set. However, the model performance went down (AUROC 0.69, sensitivity 0.91, specificity: 0.3) when both resection and needle biopsy samples were included, highlighting the importance of a representative training set to achieve robust performance in a real world setting. Further model training and validation with a more diverse dataset is required to accurately assess the performance of the model on needle biopsies. Conclusions: ML models trained on resection prostate cancer samples performed well in predicting HRD status when applied to the same sample type, demonstrating the potential of ML models to predict genomic biomarkers status in surgical specimens for treatment decision.

Efficient 3D light-sheet imaging of very large-scale optically cleared human brain and prostate tissue samples

The ability to image human tissue samples in 3D, with both cellular resolution and a large field of view (FOV), can improve fundamental and clinical investigations. Here, we demonstrate the feasibility of light-sheet imaging of ~5 cm3 sized formalin fixed human brain and up to ~7 cm3 sized formalin fixed paraffin embedded (FFPE) prostate cancer samples, processed with the FFPE-MASH protocol. We present a light-sheet microscopy prototype, the cleared-tissue dual view Selective Plane Illumination Microscope (ct-dSPIM), capable of fast 3D high-resolution acquisitions of cm3 scale cleared tissue. We used mosaic scans for fast 3D overviews of entire tissue samples or higher resolution overviews of large ROIs with various speeds: (a) Mosaic 16 (16.4 µm isotropic resolution, ~1.7 h/cm3), (b) Mosaic 4 (4.1 µm isotropic resolution, ~ 5 h/cm3) and (c) Mosaic 0.5 (0.5 µm near isotropic resolution, ~15.8 h/cm3). We could visualise cortical layers and neurons around the border of human brain areas V1&V2, and could demonstrate suitable imaging quality for Gleason score grading in thick prostate cancer samples. We show that ct-dSPIM imaging is an excellent technique to quantitatively assess entire MASH prepared large-scale human tissue samples in 3D, with considerable future clinical potential.

HMMR promotes prostate cancer proliferation and metastasis via AURKA/mTORC2/E2F1 positive feedback loop

Although dysregulated HMMR is linked to prostate cancer (PCa) prognosis, the precise mechanisms remain unclear. Here, we sought to elucidate the role of HMMR in PCa progression as well as underlying mechanism. Herein, we found that upregulation of HMMR frequently observed in PCa samples and was associated with poor prognosis. Additionally, HMMR significantly promoted PCa proliferation and metastasis through gain- and loss-of function approaches in vitro and in vivo. Mechanistically, HMMR may interact with AURKA and elevated AURKA protein level through inhibiting ubiquitination-mediated degradation, which subsequently activated mTORC2/AKT pathway to ensure the reinforcement of PCa progression. Moreover, upregulated E2F1 caused from sustained activation of mTORC2/AKT pathway in turn function as transcription factor to promote HMMR transcription, thereby forming a positive feedback loop to trigger PCa progression. Importantly, administration of the mTOR inhibitor partially antagonised HMMR-mediated PCa progression in vivo. In summary, we not only reveal a novel possible post-translation mechanism mediated by HMMR involved in AURKA regulation, but also describe a positive feedback loop that contributes to PCa deterioration, suggesting HMMR may serve as a potential promising therapeutic target in PCa.