Role In Development Of Prostate Cancer Research Articles

Abstract 4766: Androgen deprivation in mice is linked with cognitive impairment

Abstract Androgens play a neuroprotective role in maintaining the normal physiological functions of the brain. It also plays a pivotal role in prostate cancer development and progression. Advance-stage prostate cancer treatment is primarily based on androgen deprivation therapy (ADT) that blocks the male hormone testosterone. Moreover, prostate cancer patients who undergo ADT develop cognition impairment such as loss of memory, learning, reasoning, and decision-making. Several studies have shown a positive association between ADT and the risk of cognitive impairment. Currently, there are no clinical markers to identify patients at-risk to ADT-mediated cognition. This demands a need for biomarkers that can help distinguish the vulnerability of patients toward cognitive impairment undergoing ADT. We utilized a in-vivo model to identify biomarkers and the impact of ADT in different regions of the brain. Sixteen-week-old BALB/c mice were gavage 50 mg/kg/day of enzalutamide (mimicking ADT) for 5 days per week (0.2 ml of vehicle consisting of 0.5% methylcellulose and 0.025% Tween 20) for a total of 8 weeks. Control animals received 0.2 ml vehicle per day for the same time period. Mice were observed for behavioral changes post-enzalutamide treatment and brain PET scans were generated. The experiment was terminated, the brain was excised for cortex, cerebellum, and hippocampus, and subjected to mass spectroscopic (MS) analysis. Differentially expressed proteins were identified and validated using qRT-PCR in the mice blood. Enzalutamide treatment for 8 weeks resulted in a modest weight gain and lack of attention and letharginess in these mice. Examination of PET scan and H&E sections of mice brain from control group by light microscopy showed a normal morphology of neurons in the cortex. Enzalutamide treatment showed lower neuron density and signs of neuron injury, as well as cytoplasmic swelling of the astrocytes. MS analysis identified a number of differentially expressed proteins that were validated in the blood. These include ABCB10, CAB, DAZAP1, DCU, DERL1, FBXO, MBNL, PUM2, SERL1, SLC8A3, SLC9A, TCF20, VIM, and ZYXIN. Among them, the expression of SLC8A3, PUM2, and SERL1, were significantly higher than others in the enzalutamide-treated group. Taken together, our findings suggest that enzalutamide treatment in mice leads to cognitive impairment like that observed in men on ADT protocol. Our study highlights that blood-based markers can be developed for ADT-mediated cognition which can lead to the identification of new strategies for prevention and early intervention to improve the quality-of-life of patients suffering with advance-stage prostate cancer. Citation Format: Shiv Shankar Verma, Diya Swain, Vaibhav Singh, Eswar Shankar, Zhenghong Lee, Sanjay Gupta. Androgen deprivation in mice is linked with cognitive impairment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4766.

Latin American Challenges and Recommendations for Poly Adenosine Diphosphate Ribose Polymerase Inhibitor Treatment in Metastatic Castration Resistant Prostate Cancer: An Expert Overview.

In Latin America, prostate cancer is the third most common cancer overall and the most common in men, with the highest mortality rate of all cancers. In 2022, there were approximately 22,985 new prostate cancer cases and 61,056 deaths from prostate cancer in the region. Patients with metastatic disease that is resistant to cure by castration now have multiple therapeutic options, including poly-ADP ribose polymerase inhibitors. These treatment advances present new challenges, such as developing monitoring protocols for early detection of disease progression to castration resistance. The Americas Health Foundation organized a 3-day meeting with 8 regional oncologists and pathologists to create a paper on metastatic castration-resistant prostate cancer diagnosis and therapy, including the new poly-ADP ribose polymerase inhibitors. The panel examined metastatic castration-resistant prostate cancer in Latin America and recommended ways to improve patient care using published literature and their expertise. Gene mutations play an important role in prostate cancer development. Precision medicine innovations highlight the importance of genotyping DNA variants and tumor biomarkers for targeted treatment. Access to appropriate genetic testing is difficult, medications are available but expensive, and there is a lack of infrastructure and regulatory frameworks that prevent patients from benefiting from innovative therapies. The panel recommends developing a population database and biobank and creating tumor tissue collection, processing, and storage facilities. Multi-stakeholder collaboration is needed to integrate the information gathered, train staff, select target populations, improve patient accessibility, and reduce the cost burden of drugs, genetic counselors, and cancer geneticists in Latin America. Collaboration is essential among healthcare professionals, policymakers, patient advocacy groups, pharmaceutical companies, and international organizations to address these challenges and needs in Latin America.

A Bayesian fine-mapping model using a continuous global-local shrinkage prior with applications in prostate cancer analysis

The aim of fine mapping is to identify genetic variants causally contributing to complex traits or diseases. Existing fine-mapping methods employ Bayesian discrete mixture priors and depend on a pre-specified maximum number of causal variants, which may lead to sub-optimal solutions. In this work, we propose a Bayesian fine-mapping method called h2-D2, utilizing a continuous global-local shrinkage prior. We also present an approach to define credible sets of causal variants in continuous prior settings. Simulation studies demonstrate that h2-D2 outperforms current state-of-the-art fine-mapping methods such as SuSiE and FINEMAP in accurately identifying causal variants and estimating their effect sizes. We further applied h2-D2 to prostate cancer analysis and discovered some previously unknown causal variants. In addition, we inferred 369 target genes associated with the detected causal variants and several pathways that were significantly over-represented by these genes, shedding light on their potential roles in prostate cancer development and progression.

Insulin-like growth factor family and prostate cancer: new insights and emerging opportunities.

Prostate cancer is the second most commonly diagnosed cancer in men. The mammalian insulin-like growth factor (IGF) family is made up of three ligands (IGF-I, IGF-II, and insulin), three receptors (IGF-I receptor (IGF-1R), insulin receptor (IR), and IGF-II receptor (IGF-2R)), and six IGF-binding proteins (IGFBPs). IGF-I and IGF-II were identified as potent mitogens and were previously associated with an increased risk of cancer development including prostate cancer. Several reports showed controversy about the expression of the IGF family and their connection to prostate cancer risk due to the high degree of heterogeneity among prostate tumors, sampling bias, and evaluation techniques. Despite that, it is clear that several IGF family members play a role in prostate cancer development, metastasis, and androgen-independent progression. In this review, we aim to expand our understanding of prostate tumorigenesis and regulation through the IGF system. Further understanding of the role of IGF signaling in PCa shows promise and needs to be considered in the context of a comprehensive treatment strategy.

Prostate Cancer: Genetics, Epigenetics and the Need for Immunological Biomarkers.

Epidemiological data highlight prostate cancer as a significant global health issue, with high incidence and substantial impact on patients' quality of life. The prevalence of this disease is associated with various factors, including age, heredity, and race. Recent research in prostate cancer genetics has identified several genetic variants that may be associated with an increased risk of developing the disease. However, despite the significance of these findings, genetic markers for prostate cancer are not currently utilized in clinical practice as reliable indicators of the disease. In addition to genetics, epigenetic alterations also play a crucial role in prostate cancer development. Aberrant DNA methylation, changes in chromatin structure, and microRNA (miRNA) expression are major epigenetic events that influence oncogenesis. Existing markers for prostate cancer, such as prostate-specific antigen (PSA), have limitations in terms of sensitivity and specificity. The cost of testing, follow-up procedures, and treatment for false-positive results and overdiagnosis contributes to the overall healthcare expenditure. Improving the effectiveness of prostate cancer diagnosis and prognosis requires either narrowing the risk group by identifying new genetic factors or enhancing the sensitivity and specificity of existing markers. Immunological biomarkers (both circulating and intra-tumoral), including markers of immune response and immune dysfunction, represent a potentially useful area of research for enhancing the diagnosis and prognosis of prostate cancer. Our review emphasizes the need for developing novel immunological biomarkers to improve the diagnosis, prognosis, and management of prostate cancer. We highlight the most recent achievements in the identification of biomarkers provided by circulating monocytes and tumor-associated macrophages (TAMs). We highlight that monocyte-derived and TAM-derived biomarkers can enable to establish the missing links between genetic predisposition, hormonal metabolism and immune responses in prostate cancer.

3D bioprinting of multi-cellular tumor microenvironment for prostate cancer metastasis

Prostate cancer (PCa) is one of the most lethal cancers in men worldwide. The tumor microenvironment (TME) plays an important role in PCa development, which consists of tumor cells, fibroblasts, endothelial cells, and extracellular matrix (ECM). Hyaluronic acid (HA) and cancer-associated fibroblasts (CAFs) are the major components in the TME and are correlated with PCa proliferation and metastasis, while the underlying mechanism is still not fully understood due to the lack of biomimetic ECM components and coculture models. In this study, gelatin methacryloyl/chondroitin sulfate-based hydrogels were physically crosslinked with HA to develop a novel bioink for the three-dimensional bioprinting of a coculture model that can be used to investigate the effect of HA on PCa behaviors and the mechanism underlying PCa-fibroblasts interaction. PCa cells demonstrated distinct transcriptional profiles under HA stimulation, where cytokine secretion, angiogenesis, and epithelial to mesenchymal transition were significantly upregulated. Further coculture of PCa with normal fibroblasts activated CAF transformation, which could be induced by the upregulated cytokine secretion of PCa cells. These results suggested HA could not only promote PCa metastasis individually but also induce PCa cells to activate CAF transformation and form HA-CAF coupling effects to further promote PCa drug resistance and metastasis.

Prostate cancer and microRNAs: New insights into apoptosis.

Prostate cancer (PCa) is known as one of the most prevalent malignancies globally and is not yet curable owing to its progressive nature. It has been well documented that Genetic and epigenetic alterations maintain mandatory roles in PCa development. Apoptosis, a form of programmed cell death, has been shown to be involved in a number of physiological processes. Apoptosis disruption is considered as one of the main mechanism involved in lots of pathological conditions, especially malignancy. There is ample of evidence in support of the fact that microRNAs (miRNAs) have crucial roles in several cellular biological processes, including apoptosis. Escaping from apoptosis is a common event in malignancy progression. Emerging evidence revealed miRNAs capabilities to act as apoptotic or anti-apoptotic factors by altering the expression levels of tumor inhibitor or oncogene genes. In the present narrative review, we described in detail how apoptosis dysfunction could be involved in PCa processes and additionally, the mechanisms behind miRNAs affect the apoptosis pathways in PCa. Identifying the mechanisms behind the effects of miRNAs and their targets on apoptosis can provide scientists new targets for PCa treatment.

Upregulation of TLR5 indicates a favorable prognosis in prostate cancer.

Toll-like receptors (TLRs) are the key sensors of innate immunity for triggering immune responses against infections. TLRs are well known to be expressed and activated in innate immune cells, such as macrophage and dendritic cells, but we and others have found that some TLRs are also functional in epithelial cells. However, the role of an epithelial TLR in prostate cancer remains elusive. TLR5 expression in messenger RNA and protein level in prostate cancer was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC). The activation of TLR5 signaling in epithelial cells was detected upon nuclear factor-κB activation by luciferase assay and western blot analysis, and proinflammatory cytokine activation by RT-qPCR. Distinguishing between the TLR5 and NLRC4 pathways, both recognizing flagellin, is determined by small interfering RNA and proinflammatory cytokine activation. The role of TLR5 in prostate cancer was analyzed by IHC and bioinformatics using a general and single-cell database. In the present study, we show that TLR5, among other TLRs, is exceedingly expressed in human prostate cancer cells. This cancer epithelial cell TLR5 functions to activate the TLR5 signaling pathway in human prostate cancer cells, as it does with innate immune cell TLR5. The bacterial protein flagellin induces a robust immune response in prostate cancer cells in a TLR5-dependent but NLRC4-independent manner. TLR5 is highly expressed in prostate cancer patient specimens, and high TLR5 expression in prostate cancer patients indicates a favorable prognosis. TLR5, as an innate immunity receptor, is a functional TLR in human prostate cancer epithelial cells. TLR5 plays an important role in prostate cancer development and is a new potential prognosis biomarker. TLR5 may represent a novel immunotherapy target against prostate cancer.

The cancer testis antigen TDRD1 regulates prostate cancer proliferation by associating with the snRNP biogenesis machinery.

Prostate cancer is the most commonly diagnosed noncutaneous cancer in American men. TDRD1, a germ cell-specific gene, is erroneously expressed in more than half of prostate tumors, but its role in prostate cancer development remains elusive. In this study, we identified a PRMT5-TDRD1 signaling axis that regulates the proliferation of prostate cancer cells. PRMT5 is a protein arginine methyltransferase essential for small nuclear ribonucleoprotein (snRNP) biogenesis. Methylation of Sm proteins by PRMT5 is a critical initiation step for assembling snRNPs in the cytoplasm, and the final snRNP assembly takes place in Cajal bodies in the nucleus. By mass spectrum analysis, we found that TDRD1 interacts with multiple subunits of the snRNP biogenesis machinery. In the cytoplasm, TDRD1 interacts with methylated Sm proteins in a PRMT5-dependent manner. In the nucleus, TDRD1 interacts with Coilin, the scaffold protein of Cajal bodies. Ablation of TDRD1 in prostate cancer cells disrupted the integrity of Cajal bodies, affected the snRNP biogenesis, and reduced cell proliferation. Taken together, this study represents the first characterization of TDRD1 functions in prostate cancer development and suggests TDRD1 as a potential therapeutic target for prostate cancer treatment.

Discovery of PIM-1 kinase inhibitors based on the 2,5-disubstituted 1,3,4-oxadiazole scaffold against prostate cancer: Design, synthesis, in vitro and in vivo cytotoxicity investigation

PIM-1 kinases play an established role in prostate cancer development and progression. This research work tackles the design and synthesis of new PIM-1 kinase targeting 2,5-disubstituted-1,3,4-oxadiazoles 10a-g&11a-f, and investigation thereof as potential anti-cancer agents through in vitro cytotoxicity assay followed by in vivo studies along with exploration of this chemotype's plausible mechanism of action. In vitro cytotoxicity experiments have disclosed 10f as the most potent derivative against PC-3 cells (IC50 = 16 nM) compared to the reference drug Staurosporine (IC50 = 0.36 μM), also eliciting good cytotoxicity against HepG2 and MCF-7 cells (IC50 = 0.13 and 5.37 μM, respectively). Investigating PIM-1 kinase inhibitory activity of compound 10f revealed an IC50 of 17 nM paralleled to that of Staurosporine (IC50 = 16.7 nM). Furthermore, compound 10f displayed an antioxidant activity eliciting a DPPH inhibition ratio of 94% as compared to Trolox (96%). Further investigation demonstrated that 10f induced apoptosis in treated PC-3 cells by 43.2-fold (19.44%) compared to 0.45% in control. 10f also disrupted the PC-3 cell cycle by increasing the cell population at the PreG1-phase by 19.29-fold while decreasing the G2/M-phase by 0.56-fold compared to control. Moreover, 10f affected a downregulation of JAK2, STAT3 and Bcl-2 and upregulation of caspases 3, 8 and 9 levels that activated the caspase-dependent apoptosis. Finally, in vivo 10f-treatment caused a significant increase in tumor inhibition by 64.2% compared to 44.5% in Staurosporine treatment of the PC-3 xenograft mouse model. Additionally, it improved the hematological, biochemical parameters, and histopathological examinations compared to control untreated animals. Finally, docking of 10f with the ATP-binding site of PIM-1 kinase demonstrated good recognition of and effective binding to the active site. In conclusion, compound 10f represents a promising lead compound that merits further future optimization for controlling prostate cancer.

Myeloid-Derived Suppressor Cells as Key Players and Promising Therapy Targets in Prostate Cancer.

Prostate cancer (PC) is the second most often diagnosed malignancy in men and one of the major causes of cancer death worldwide. Despite genetic predispositions, environmental factors, including a high-fat diet, obesity, a sedentary lifestyle, infections of the prostate, and exposure to chemicals or ionizing radiation, play a crucial role in PC development. Moreover, due to a lack of, or insufficient T-cell infiltration and its immunosuppressive microenvironment, PC is frequently classified as a “cold” tumor. This is related to the absence of tumor-associated antigens, the lack of T-cell activation and their homing into the tumor bed, and the presence of immunological cells with regulatory functions, including myeloid-derived suppressor cells (MDSCs), regulatory T cells (Treg), and tumor-associated macrophages (TAMs). All of them, by a variety of means, hamper anti-tumor immune response in the tumor microenvironment (TME), stimulating tumor growth and the formation of metastases. Therefore, they emerge as potential anti-cancer therapy targets. This article is focused on the function and role of MDSCs in the initiation and progression of PC. Clinical trials directly targeting this cell population or affecting its biological functions, thus limiting its pro-tumorigenic activity, are also presented.

Abstract 2353: Biphasic regulation of MYB by androgen signaling mediates its growth-promoting and repressive effects in prostate cancer cells

Abstract Prostate cancer is the most frequently diagnosed malignancy affecting millions of men worldwide. It is also the second leading cause of cancer-related death in American men. Androgen signaling plays a central role in prostate cancer development but results in growth inhibition at high doses. Mechanisms underlying such biphasic effect of androgens are not well understood. We recently identified MYB as an aberrantly expressed gene in prostate cancer cells, which promoted their growth and aggressive behavior. We also observed that MYB induced ligand-independent activation of androgen receptor (AR) and influenced its binding to selective target genes to promote castration-resistance. The goal of the present study was to examine the regulatory crosstalk between MYB and AR in prostate cancer cells. We observed that while MYB had no significant effect on AR expression, androgen (dihydrotestosterone, DHT) treatment resulted in a dose-dependent biphasic regulation of MYB at both transcript and protein levels correlating with its effect on the growth of prostate cancer cells. Interestingly, we observed that the treatment of prostate cancer cells with either low (1 nM) or high (100 nM) doses of DHT enhanced the transcriptional activity of MYB promoter. In silico analysis identified two potential androgen-responsive elements (AREs) in MYB promoter and AR bound more efficiently to the proximal sequence as determined by chromatin immunoprecipitation (ChIP). In a time-course experiment, we observed that both low and high doses of DHT increased MYB transcript and protein levels at early time points, which decreased sharply after 12 h in high dose DHT-treated prostate cancer cells. RNA stability assay following treatment with actinomycin D (inhibitor of transcription) showed decreased MYB mRNA half-life in prostate cancer cells at late time points when treated with high dose DHT. Profiling of MYB-targeted miRNAs showed significantly greater induction of miR-150 in high-dose DHT-treated prostate cancer cells than those treated with low-dose DHT. Two AREs were predicted in the 1000 bp upstream sequence of miR-150 transcription start site and AR binding was confirmed by ChIP assay. Functional inhibition of miR-150 using anti-miR relieved MYB suppression by high-dose DHT and promoted the growth of prostate cancer cells. Further, transfection of prostate cancer cells by miR-150 mimic reduced endogenous MYB levels and led to repression of growth of prostate cancer cells. Overall, our findings reveal a novel mechanism of MYB regulation that mediates, at least in part, the biphasic effect of androgens on the growth of prostate cancer cells. Citation Format: Srijan Acharya, Shashi Anand, Mohammad Aslam Khan, Haseeb Zubair, Sanjeev Kumar Srivastava, Seema Singh, Ajay Pratap Singh. Biphasic regulation of MYB by androgen signaling mediates its growth-promoting and repressive effects in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2353.

Orphan receptors in prostate cancer.

The identification of new cellular receptors has been increasing rapidly. A receptor is called "orphan" if an endogenous ligand has not been identified yet. Here we review receptors that contribute to prostate cancer and are considered orphan or partially orphan. This means that the full spectrum of their endogenous ligands remains unknown. The orphan receptors are divided into two major families. The first group includes G protein-coupled receptors. Most are orphan olfactory receptors. OR51E1 inhibits cell proliferation and induces senescence in prostate cancer. OR51E2 inhibits prostate cancer growth, but promotes invasiveness and metastasis. GPR158, GPR110, and GPCR-X play significant roles in prostate cancer development and progression. However, GPR160 induces cell cycle arrest and apoptosis. The other major subset of orphan receptors are nuclear receptors. Receptor-related orphan receptor α (RORα) inhibits tumor growth, but RORγ stimulates androgen receptor signaling. PXR contributes to metabolic deactivation of androgens and inhibits cell proliferation. TLX has protumorigenic effects in prostate cancer, while its knockdown triggers cellular senescence and growth arrest. Estrogen-related receptor ERRγ can inhibit tumor growth but ERRα is protumorigenic. Dax1 and short heterodimeric partner are also inhibitory in prostate cancer. There is a "zoo" of relatively underappreciated orphan receptors that play key roles in prostate cancer.

Citric Acid as a Potential Prostate Cancer Biomarker Determined in Various Biological Samples.

Despite numerous studies, the molecular mechanism of prostate cancer development is still unknown. Recent investigations indicated that citric acid and lipids—with a special emphasis on fatty acids, steroids and hormones (ex. prolactin)—play a significant role in prostate cancer development and progression. However, citric acid is assumed to be a potential biomarker of prostate cancer, due to which, the diagnosis at an early stage of the disease could be possible. For this reason, the main goal of this study is to determine the citric acid concentration in three different matrices. To the best of our knowledge, this is the first time for citric acid to be determined in three different matrices (tissue, urine and blood). Samples were collected from patients diagnosed with prostate cancer and from a selected control group (individuals with benign prostatic hyperplasia). The analyses were performed using the rapid fluorometric test. The obtained results were correlated with both the histopathological data (the Gleason scale as well as the Classification of Malignant Tumors (pTNM) staging scale) and the biochemical data (the values of the following factors: prostate specific antigen, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, total cholesterol, creatinine and prolactin) using chemometric methods. For tissue samples, the results indicated a decreased level of citric acid in the case of prostate cancer. The analyte average concentrations in serum and urine appeared to be corresponding and superior in the positive cohort. This trend was statistically significant in the case of urinary citric acid. Moreover, a significant negative correlation was demonstrated between the concentration of citric acid and the tumor stage. A negative correlation between the total cholesterol and high-density lipoprotein and prolactin was particularly prominent in cancer cases. Conversely, a negative association between low-density lipoprotein and prolactin levels was observed solely in the control group. On the basis of the results, one may assume the influence of hormones, particularly prolactin, on the development of prostate cancer. The present research allowed us to verify the possibility of using citric acid as a potential biomarker for prostate cancer.

Tripartite Motif-Containing Protein 11 Reverses Paclitaxel Resistance in Prostate Cancer Drug-Resistant Cells by Mediating Family with Sequence Similarity 46B Expression

Tripartite motif-containing protein 11 (TRIM11) and family with sequence similarity 46B (FAM46B) have been demonstrated to play roles in prostate cancer development, but their function in paclitaxel resistance remains unclear. The role of TRIM11 and FAM46B in paclitaxel resistance in prostate cancer was estimated. The paclitaxel-resistant cells were established with gradually increasing concentrations of paclitaxel in prostate cancer cells. The sensitivity to paclitaxel of established cells was assessed by the value of the median inhibitory concentration in the presence of 0-1000 nM paclitaxel. The expression level of TRIM11 and FAM46B was evaluated by real-time quantitative polymerase chain reaction. The proliferation, migration, and invasion of established cells were evaluated by CCK8 and Tran-swell assay. TRIM11 was upregulated in paclitaxel-resistant cells and promoted the proliferation, migration, and invasion of established cells. The significant downregulation of FAM46B was observed in paclitaxel-resistant cells. Although the overexpression of FAM46B suppressed the viability and metastasis of paclitaxel-resistant cells, which was reversed by the upregulation of TRIM11. Both the knockdown of TRIM11 and overexpression of FAM46B could enhance paclitaxel sensitivity of established resistant cells. The promoted effect of FAM46B overexpression was alleviated by the elevation of TRIM11. TRIM11 could improve the sensitivity to paclitaxel of resistant prostate cancer cells via regulating FAM46B.

BoxCar and shotgun proteomic analyses reveal molecular networks regulated by UBR5 in prostate cancer.

Prostate cancer (PC) is a major health and economic problem in industrialized countries, yet our understanding of the molecular mechanisms of PC progression and drug response remains limited. Accumulating evidence showed that certain E3 ubiquitin ligases such as SIAH2, RNF7, and SPOP play important roles in PC development and progression. However, the roles and mechanisms of other E3s in PC progression remain largely unexplored. Through an integration analysis of clinical genomic and transcriptomic profiles of PC tumors, this study identified UBR5 as a top PC-relevant E3 ubiquitin ligase whose expression levels are strongly associated with PC progression and aggressiveness. BoxCar and shotgun proteomic analyses of control and UBR5-knockdown PC3 cells complementarily identified 75 UBR5-regulated proteins. Bioinformatic analysis suggested that the 75 proteins form four molecular networks centered around FANCD2, PAF1, YY1, and LAMB3 via direct protein-protein interactions. Experimental analyses demonstrated that UBR5 associates with and downregulates two key DNA damage repair proteins (XRCC3 and FANCD2) and confers PC cell sensitivity to olaparib, a PARP inhibitor in clinical use for cancer therapy. This study represents the first application of BoxCar in PC research, provides new insights into the molecular functions of UBR5 in PC, and suggests that PC patients with UBR5-high tumors may potentially benefit from PARP inhibitor treatment.

A Small Peptide Targeting the Ligand-Induced Androgen Receptor/Filamin a Interaction Inhibits the Invasive Phenotype of Prostate Cancer Cells.

Prostate cancer (PC) is one of the most widespread malignancies among males worldwide. The androgen receptor (AR) plays a major role in prostate cancer development and progression and is the main target of PC therapy. Nonetheless, its action is not yet fully elucidated. We report here that the AR associates with Filamin A (FlnA) promoting migration and invasiveness of various PC-derived cells after androgen challenging. Inhibition of the AR/FlnA complex assembly by a very low concentration of Rh-2025u, an AR-derived peptide specifically interfering with this association, impairs such phenotype in monolayer cells and in 3D models. This study, together with our recent data in cancer-associated fibroblasts (CAFs), indicates that targeting the AR/FlnA complex could improve the clinical management of invasive PC, as the limited number of new drugs reaching the market suggests that we must re-examine the way invasive PC is currently treated. In this context, the synthesis of new biologically active molecules, such as the Rh-2025u peptide, which has been shown to efficiently interfere in the complex assembly in CAFs and PC cells, should overcome the limits of current available therapies, mostly based on hormone antagonists.

The Dual Effect of the HDAC Inhibitor Romidepsin on Androgen Receptor Signaling and DNA Damage Repair in Prostate Cancer.

Aberrant epigenetic modifications play an important role in prostate cancer development and progression. Histone deacetylase inhibitors (HDACi) are a novel class of small-molecular compounds that have been shown to have activity in several tumor types. Some HDACi's induce a stress response that affects DNA damage repair (radiosensitization) and androgen receptor (AR) signaling (increased sensitivity to androgen blockage). We hypothesized that the HDACi, romidepsin, would increase prostate cancer cell killing through dual effects on AR signaling and radiation DNA damage response.The prostate cancer cell lines LNCaP (androgen sensitive) and 22Rv1 (androgen insensitive) were treated with romidepsin (10 nM) plus or minus 2 Gy radiation. The added effect of enzalutamide (10 mM) was also tested. Cell viability was performed by Real-time Cell assay (RTCA), whole-transcriptome analysis by RNA sequencing, western blot analyses, immunofluorescent quantification of γ-H2AX double strand break foci, and colonogenic survival. Western blot analysis was used to measure the expression of (i) AR signaling pathway proteins that included wild-type AR and its AR-V7 splice variant and (ii) DNA repair genes that included Rad51, DNA-PK and γ-H2AX.Romidepsin reduced cell viability by RTCA of both cell lines in a dose dependent manner. The addition of enzalutamide further reduced cell viability and clonogenic survival. Gene ontology analysis from RNA-Seq data in both LNCaP and 22Rv1 cells revealed that romidepsin suppressed pathways related to prostate cancer aggressiveness including the AR, MYC, DNA damage response, and cell cycle progression pathways. By western blot analysis, romidepsin suppressed AR (LNCaP) and AR-V7 (22Rv1) expression and reduced DNA repair genes including RAD51, DNA-PK and phospho-ATM levels. After 2 Gy radiation, we found that treatment with 10nM romidepsin for 24 hours resulted in an increase in γ-H2AX foci in 35.2% in LNCaP and 27% in 22Rv1 cells respectively. By colonogenic assay, 10 nM romidepsin for 24 hours prior to 2 Gy to 8 Gy radiation resulted in a significant reduction in the surviving fractions. The addition of enzalutamide resulted in the greatest reduction in colonogenic survival.Our study demonstrated for the first time that HDACi romidepsin exerted dual effects on AR signaling and DNA damage response genes in androgen sensitive and insensitive prostate cancer cell lines, and that there is an added suppressive effect with the addition of enzalutamide to HDAC inhibition plus radiation. The use of HDACi's have promise clinically for the treatment of high-risk prostate cancer, for which androgen deprivation plus radiotherapy are the standard treatments.

A transcriptome-wide association study identifies novel candidate susceptibility genes for prostate cancer risk.

A large proportion of heritability for prostate cancer risk remains unknown. Transcriptome-wide association study combined with validation comparing overall levels will help to identify candidate genes potentially playing a role in prostate cancer development. Using data from the Genotype-Tissue Expression Project, we built genetic models to predict normal prostate tissue gene expression using the statistical framework PrediXcan, a modified version of the unified test for molecular signatures and Joint-Tissue Imputation. We applied these prediction models to the genetic data of 79 194 prostate cancer cases and 61 112 controls to investigate the associations of genetically determined gene expression with prostate cancer risk. Focusing on associated genes, we compared their expression in prostate tumor vs normal prostate tissue, compared methylation of CpG sites located at these loci in prostate tumor vs normal tissue, and assessed the correlations between the differentiated genes' expression and the methylation of corresponding CpG sites, by analyzing The Cancer Genome Atlas (TCGA) data. We identified 573 genes showing an association with prostate cancer risk at a false discovery rate (FDR) ≤ 0.05, including 451 novel genes and 122 previously reported genes. Of the 573 genes, 152 showed differential expression in prostate tumor vs normal tissue samples. At loci of 57 genes, 151 CpG sites showed differential methylation in prostate tumor vs normal tissue samples. Of these, 20 CpG sites were correlated with expression of 11 corresponding genes. In this TWAS, we identified novel candidate susceptibility genes for prostate cancer risk, providing new insights into prostate cancer genetics and biology.

Prevalence of Human Polyomavirus BK Virus in Prostate Cancer Patients and Benign Prostatic Hyperplasia: A Cross-sectional Study on Prostate Patients Referred to Imam Khomeini Hospital in Ahvaz Between 2015 and 2017

Background: Human polyomavirus BK virus (BKV) belongs to the Polyomaviridae family and seems to be a drastic virus in prostate cancer (PCa) etiology. BK virus induces oncogenesis via the expression of large tumor antigen (LTAg) and small tumor antigen (stAg). Also, BKV infection seems to play an essential role in prostate cancer development. Objectives: In this study was aimed to study the prevalence of BKV in benign and cancerous prostate tissues. Methods: In this study, 100 formalin-fixed paraffin-embedded tissues of PCa specimens and benign prostatic hyperplasia (BPH) were collected. The DNA was extracted from tissue samples, and the BKV DNA was investigated using a semi-nested polymerase chain reaction (PCR). The MEGA 6.0 software was used for phylogenetic analysis to assemble the viral genome. A phylogenetic tree was constructed by neighbor-joining analysis with 1,000 replicates of the bootstrap resampling test. Results: The BKV DNA was found in 66% (33/50) of patients with PCa and 36% (18/50) of patients with benign prostatic hyperplasia (BPH) (P = 0.003). The frequency of BKV DNA in different classes of Gleason score (5 - 10) was not significant (0.094). The distribution of BKV DNA among different age groups was not significant (P = 0.086). Conclusions: High frequency of BKV infection was detected in patients with PCa compared to patients with BPH (P = 0.003), and the coexistence of BKV DNA was confirmed in 51% (51/100) of tissue samples, which were confirmed to be subtype 1 of BKV infection.