The high degree of conservation in microRNA from Caenorhabditis elegans to humans has enabled relatively rapid implementation of findings in model systems to the clinic. The convergence of the capacity for genomic screening being implemented in the prevailing precision medicine initiative and the capabilities of microRNA to address these changes holds significant promise. However, prostate, ovarian and breast cancers are heterogeneous and face issues of evolving therapeutic resistance. The transforming growth factor-beta (TGFβ) signaling axis plays an important role in the progression of these cancers by regulating microRNAs. Reciprocally, microRNAs regulate TGFβ actions during cancer progression. One must consider the expression of miRNA in the tumor microenvironment a source of biomarkers of disease progression and a viable target for therapeutic targeting. The differential expression pattern of microRNAs in health and disease, therapeutic response and resistance has resulted in its application as robust biomarkers. With two microRNA mimetics in ongoing restorative clinical trials, the paradigm for future clinical studies rests on the current observational trials to validate microRNA markers of disease progression. Some of today’s biomarkers can be translated to the next generation of microRNA-based therapies.
Bethany Smith, Priyanka Agarwal and Neil A Bhowmick
Rajeev Mishra, Subhash Haldar, Surabhi Suchanti and Neil A Bhowmick
Genomic changes that drive cancer initiation and progression contribute to the co-evolution of the adjacent stroma. The nature of the stromal reprogramming involves differential DNA methylation patterns and levels that change in response to the tumor and systemic therapeutic intervention. Epigenetic reprogramming in carcinoma-associated fibroblasts are robust biomarkers for cancer progression and have a transcriptional impact that support cancer epithelial progression in a paracrine manner. For prostate cancer, promoter hypermethylation and silencing of the RasGAP, RASAL3 that resulted in the activation of Ras signaling in carcinoma-associated fibroblasts. Stromal Ras activity initiated a process of macropinocytosis that provided prostate cancer epithelia with abundant glutamine for metabolic conversion to fuel its proliferation and a signal to transdifferentiate into a neuroendocrine phenotype. This epigenetic oncogenic metabolic/signaling axis seemed to be further potentiated by androgen receptor signaling antagonists and contributed to therapeutic resistance. Intervention of stromal signaling may complement conventional therapies targeting the cancer cell.
Veronica R Placencio-Hickok, Anisha Madhav, Sungjin Kim, Frank Duong, Bryan Angara, Zhenqiu Liu and Neil A Bhowmick
While the overall 5-year survival rate for prostate cancer is near 100%, up to 35% of patients will develop recurrent disease. At the time of prostatectomy, prostate-specific antigen (PSA) is used to guide primary therapy with the goal of curative intervention. It can be valuable to know when primary therapy may not in fact be curative, so that subsequent adjuvant therapy can be administered at an early stage to limit progression. We examined prostate cancer patients with PSA ≤10 ng/mL that were all subjected to prostatectomy with at least 5 years of follow-up (n = 181). Based on data that endoglin (CD105) signaling in the tumor can contribute to prostate cancer progression, we examined the expression of soluble CD105 (sCD105) in the patient plasma. To determine the relation of plasma sCD105 measures to cellular CD105 in tissues, we tested an independent set of prostate cancer tissues and paired plasma (n = 31). Elevated sCD105 was found to be associated with recurrence-free survival of prostate cancer patients. Further, sCD105 levels in patient plasma were inversely correlated with cellular CD105 expression. This translational study supported preclinical data demonstrating the pro-tumorigenic capacity of cellular CD105 and provide a blood-based biomarker, sCD105, for prostate cancer recurrence in prostatectomy patients with PSA levels ≤10 ng/mL.
Neil A Bhowmick, Jillian Oft, Tanya Dorff, Sumanta Pal, Neeraj Agarwal, Robert A Figlin, Edwin M Posadas, Stephen J Freedland and Jun Gong
The current pandemic (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global health challenge with active development of antiviral drugs and vaccines seeking to reduce its significant disease burden. Early reports have confirmed that transmembrane serine protease 2 (TMPRSS2) and angiotensin converting enzyme 2 (ACE2) are critical targets of SARS-CoV-2 that facilitate viral entry into host cells. TMPRSS2 and ACE2 are expressed in multiple human tissues beyond the lung including the testes where predisposition to SARS-CoV-2 infection may exist. TMPRSS2 is an androgen-responsive gene and its fusion represents one of the most frequent alterations in prostate cancer. Androgen suppression by androgen deprivation therapy and androgen receptor signaling inhibitors form the foundation of prostate cancer treatment. In this review, we highlight the growing evidence in support of androgen regulation of TMPRSS2 and ACE2 and the potential clinical implications of using androgen suppression to downregulate TMPRSS2 to target SARS-CoV-2. We also discuss the future directions and controversies that need to be addressed in order to establish the viability of targeting TMPRSS2 and/or ACE2 through androgen signaling regulation for COVID-19 treatment, particularly its relevance in the context of prostate cancer management.