Updates on Molecular and Biochemical Development and Progression of Prostate Cancer

Contemporaneous and upcoming trends in immunotherapy for prostate cancer: review

Prostate cancer (PCa) is the most common cancer in men worldwide. It affects more than 1.4 million men worldwide and kills up to 37 5000 people. PCa is routinely managed with chemotherapy and androgen deprivation therapy, but the success rate of these treatments is unsatisfactory. Immunotherapy is a novel method of treating different types of cancers, and it utilizes the body's own immune system to fight cancer. Different types of cancer respond differently to immunotherapy, with some showing excellent responses, while others do not show very satisfactory responses. PCa is known to be an immunologically cold tumor, such that conventional immunotherapy does not work as effectively as it works in other cancers. In the past decade, multiple studies and trials have been conducted to test different types of therapies, ranging from immune checkpoint inhibitors to anticancer vaccines to anticancer cytokines. Even after many studies, there is still a drug to be discovered that can completely cure any stage of PCa. Recent immunotherapeutic drug trials have started using immunotherapy in conjunction with chemotherapy and radiotherapy and have shown promising results. In this paper, the authors present a comprehensive overview of the currently used immunotherapeutic drugs as well as emerging immunotherapies, including modalities of combination immunotherapy with radiotherapy and chemotherapy. This review can help readers gain the latest knowledge about emerging trends in the current immunotherapy landscape for the treatment of PCa, as well as a general overview of the already used immunotherapy drugs for PCa.

Characterization of the TRPV6 calcium channel-specific phenotype by RNA-seq in castration-resistant human prostate cancer cells

Background: Transient receptor potential vanilloid subfamily member 6 (TRPV6), a highly calcium-selective channel, has been shown to play a significant role in calcium homeostasis and to participate both in vitro and in vivo in growth, cell survival, and drug resistance of prostate cancer. Its role and the corresponding calcium-dependent pathways were mainly studied in hormone-dependent human prostate cancer cell lines, often used as a model of early-stage prostate cancers. The goal of the present study was to describe the TRPV6-specific phenotype and signaling pathways it is involved in, using castration-resistant prostate cancer cell lines. Methods: RNA sequencing (RNA-seq) was used to study the gene expression impacted by TRPV6 using PC3Mtrpv6-/- versus PC3Mtrpv6+/+ and its derivative PC3M-luc-C6trpv6+/+ cell line in its native and TRPV6 overexpressed form. In addition to the whole-cell RNA sequencing, immunoblotting, quantitative PCR, and calcium imaging were used to validate trpv6 gene status and functional consequences, in both trpv6 -/- and TRPV6 overexpression cell lines. Results: trpv6 -/- status was validated using both immunoblotting and quantitative PCR, and the functional consequences of either trpv6 gene deletion or TRPV6 overexpression were shown using calcium imaging. RNA-seq analysis demonstrated that the calcium channel TRPV6, being a crucial player of calcium signaling, significantly impacts the expression of genes involved in cancer progression, such as cell cycle regulation, chemotaxis, migration, invasion, apoptosis, ferroptosis as well as drug resistance, and extracellular matrix (ECM) re-organization. Conclusion: Our data suggest that the trpv6 gene is involved in and regulates multiple pathways related to tumor progression and drug resistance in castration-resistant prostate cancer cells.

Adverse Events and Tolerability of Combined Durvalumab and Tremelimumab versus Durvalumab Alone in Solid Cancers: A Systematic Review and Meta-Analysis

Background: Recently, the combination of durvalumab and tremelimumab, two immune checkpoint inhibitors, for the treatment of different types of cancers has been considered; however, its overall effects, including its safety, are still unclear and need to be further investigated. Objectives: The aim of the present systematic review and meta-analysis was to investigate the safety and tolerability of this combination of drugs. Methods: A systematic review of the literature, based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, was conducted by employing online electronic databases and the American Society of Clinical Oncology (ASCO) Meeting Library. The selection of eligible publications was made following a staged screening and selection process. The software RevMan 5.4 was used to run the quantitative analysis and forest plots, while the Cochrane tool was employed for risk of bias assessment. Results: From the retrieved 157 results, 9 randomized controlled trials involving 3060 patients were included. By comparing the combination of durvalumab and tremelimumab vs. durvalumab monotherapy, it was observed that: adverse events (AEs) ≥ Grade 3 incidence was 32.6% (536/1646) vs. 23.8% (336/1414) (Z = 2.80; p = 0.005; risk ratio (RR) = 1.44), reduced appetite incidence was 10.8% (154/1427) vs. 8.3% (108/1305) (Z = 2.26; p = 0.02; RR = 1.31), diarrhea was reported in 15.6% (229/1473) vs. 8.1% (110/1352) (Z = 5.90; p < 0.00001; RR = 1.91), rash incidence was equal to 11.1% (160/1441) vs. 6.5% (86/1320) (Z = 4.35; p <0.0001; RR = 1.75), pruritis was 13.6% (201/1473) vs. 7.7% (104/1352) (Z = 5.35; p < 0.00001; RR = 1.83), fever was 10.5% (42/399) vs. 6.6% (22/330) (Z = 2.27; p = 0.02; RR = 1.77), discontinuation rate was 18% (91/504) vs. 3% (36/434) (Z = 4.78; p < 0.00001; RR = 2.41), and death rate was 2.6% (13/504) vs. 0.7% (3/434) (Z = 1.90; p = 0.06; RR = 2.77). Conclusions: It was observed that the combined (durvalumab and tremelimumab) vs. monotherapy (durvalumab) is associated with a higher risk of treatment discontinuation, mortality, fever, diarrhea, rash, pruritis, and reduced appetite. This information is relevant and should be disclosed, especially to patients that are currently enrolled in clinical trials considering this combined therapy.

Oxidative Stress and Redox-Dependent Signaling in Prostate Cancer

Tumor emergence and progression is complicated by the dual role of reactive oxygen species (ROS). Low concentrations of ROS are essential for many intracellular metabolic processes and cell proliferation, while excessive ROS generation disrupts the mechanisms of cancer suppression, leading to the cell damage and death. A long-term imbalance in the ROS/antioxidant ratio and upregulation of the ROS generation due to the reduced efficacy of the antioxidant defense system cause chronic oxidative stress resulting in the damage of proteins, lipid, and DNA molecules and cancer development. Numerous data demonstrate that prostate cancer (the most common cancer in males) is associated with the development of oxidative stress. However, the reasons for the emergence of prostate cancer, as well as changes in the redox signaling and cellular redox homeostasis in this disease, are still poorly understood. The review examines the role of prooxidant and antioxidant enzyme systems, the imbalance in their activity leading to the oxidative stress development, changes in the key components of redox signaling, and the role of microRNAs in the modulation of redox status of cancer cells in prostate cancer.

A comprehensive gene expression profile analysis of prostate cancer cells resistant to paclitaxel and the potent target to reverse resistance

Background: Paclitaxel resistance is the major clinical obstacle in the chemotherapy of prostate cancer (PCa), but the resistant mechanism is less investigated.Purpose: To establish two paclitaxel-resistant PCa cells, provide a comprehensive gene expression profile analysis of resistant cells and the potential target to reverse resistance.Methods: Two Paclitaxel-resistant PCa cells (PC3/PR, LNcap/PR) were established by gradually increasing drug concentration. MTT and transwell assays were performed to detect drug sensitivity, cell proliferation and migration abilities. RNA-Sequencing (RNA-seq) and bioinformatic analyses were performed to identify abnormally expressed genes (AEGs) in resistant cells, and annotate the biological functions of AEGs. The role of the candidate AEG, TLR-4, on the resistant phenotypes was further investigated.Results: The resistance index of resistant cells was 2-3, and they showed a slower proliferation and increased migration ability. 4741 AEGs were screened out (Log2fold change absolute: log2FC(abs)  > 1) in the resistant cells, and they were enriched in 2'-5'-oligoadenylate synthetase activity and chemical carcinogenesis. A number of AEGs, CCND2, IGFBP3, FOS, SHH, ZEB2, and members of FGF, FGFR and WNT families were also identified to be involved in cancer- and resistant phenotype-related processes. Finally, TLR-4 was validated significantly increased in resistant cells, and knockdown of TLR-4 increased drug-sensitivity, inhibited the proliferation and migration abilities.Conclusions: The study provided a comprehensive gene expression profile of paclitaxel-resistant PCa cells, and TLR-4 could be a potential target to reverse paclitaxel resistance.

Oncological Response and Predictive Biomarkers for the Checkpoint Inhibitors in Castration-Resistant Metastatic Prostate Cancer: A Systematic Review and Meta-Analysis

Recently, checkpoint inhibitors have been investigated in metastatic prostate cancer, however their overall effect is unclear and needs to be further investigated. Objectives: The aim of this systematic review is to investigate the oncological response of metastatic castration-resistant prostate cancer patients to immune checkpoint inhibitors. Methods: Based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement, a systematic review of the literature was conducted through online electronic databases and the American Society of Clinical Oncology (ASCO) Meeting Library. Eligible publications were selected after a staged screening and selection process. RevMan 5.4 software was employed to run the quantitative analysis and forest plots. Risk of bias assessment was conducted using the Cochrane tool and Newcastle–Ottawa Scale for the randomized and non-randomized trials, respectively. Results: From the 831 results retrieved, 8 studies including 2768 patients were included. There was no significant effect on overall survival (OS) (overall response (OR) = 0.98; Z = 0.42; p = 0.67). Meanwhile, progression-free survival (PFS) was significantly better with immune checkpoint inhibitors administration (OR = 0.85; Z = 3.9; p < 0.0001). The subgroup analysis for oncological outcomes based on programmed death ligand 1 (PD-L1) positivity status displayed no significant effect, except on prostate-specific antigen response rate (PSA RR) (OR = 3.25; Z = 2.29; p = 0.02). Based on DNA damage repair (DDR), positive patients had a significantly better PFS and a trend towards better OS and overall response rate (ORR); the ORR was 40% in positive patients compared to 20% in the negative patients (OR = 2.46; Z = 1.3; p = 0.19), while PSA RR was 23.5% compared to 14.3% (OR = 1.88; Z = 0.88; p = 0.38). Better PFS was clearly associated with DDR positivity (OR = 0.70; Z = 2.48; p = 0.01) with a trend towards better OS in DDR positive patients (OR = 0.71; Z = 1.38; p = 0.17). Based on tumor mutation burden (TMB), ORR was 46.7% with high TMB versus 8.8% in patients with low TMB (OR = 11.88; Z = 3.0; p = 0.003). Conclusions: Checkpoint inhibitors provide modest oncological advantages in metastatic castration-resistant prostate cancer. There are currently no good predictive indicators that indicate a greater response in some patients.