Role of the DNA damage response in prostate cancer formation, progression and treatment

Exploring the tumor genomic landscape of aggressive prostate cancer by whole-genome sequencing of tissue or liquid biopsies

Treatment resistance remains a major issue in aggressive prostate cancer (PC), and novel genomic biomarkers may guide better treatment selection. Circulating tumor DNA (ctDNA) can provide minimally invasive information about tumor genomes, but the genomic landscape of aggressive PC based on whole-genome sequencing (WGS) of ctDNA remains incompletely characterized. Thus, we here performed WGS of tumor tissue (n = 31) or plasma ctDNA (n = 10) from a total of 41 aggressive PC patients, including 11 hormone-naïve, 15 hormone-sensitive, and 15 castration-resistant patients. Across all variant types, we found progressively more altered tumor genomic profiles in later stages of aggressive PC. The potential driver genes most frequently affected by single-nucleotide variants or insertions/deletions included the known PC-related genes TP53, CDK12, and PTEN and the novel genes COL13A1, KCNH3, and SENP3. Etiologically, aggressive PC was associated with age-related and DNA repair-related mutational signatures. Copy number variants most frequently affected 14q11.2 and 8p21.2, where no well-recognized PC-related genes are located, and also frequently affected regions near the known PC-related genes MYC, AR, TP53, PTEN, and BRCA1. Structural variants most frequently involved not only the known PC-related genes TMPRSS2 and ERG but also the less extensively studied gene in this context, PTPRD. Finally, clinically actionable variants were detected throughout all stages of aggressive PC and in both plasma and tissue samples, emphasizing the potential clinical applicability of WGS of minimally invasive plasma samples. Overall, our study highlights the feasibility of using liquid biopsies for comprehensive genomic characterization as an alternative to tissue biopsies in advanced/aggressive PC.

Homologous Recombination Repair Gene Mutations in Prostate Cancer: Prevalence and Clinical Value

Despite advances in our understanding of the molecular landscape of prostate cancer and the development of novel biomarker-driven therapies, the prognosis of patients with metastatic prostate cancer that is resistant to conventional hormonal therapy remains poor. Data suggest that a significant proportion of patients with metastatic castration-resistant prostate cancer (mCRPC) have mutations in homologous recombination repair (HRR) genes and may benefit from poly(ADP-ribose) polymerase (PARP) inhibitors. However, the adoption of HRR gene mutation testing in prostate cancer remains low, meaning there is a missed opportunity to identify patients who may benefit from targeted therapy with PARP inhibition, with or without novel hormonal agents. Here, we review the current knowledge regarding the clinical significance of HRR gene mutations in prostate cancer and discuss the efficacy of PARP inhibition in patients with mCRPC. This comprehensive overview aims to increase the clinical implementation of HRR gene mutation testing and inform future efforts in personalized treatment of prostate cancer.

Novel frontiers in urogenital cancers: from molecular bases to preclinical models to tailor personalized treatments in ovarian and prostate cancer patients

Over the last few decades, the incidence of urogenital cancers has exhibited diverse trends influenced by screening programs and geographical variations. Among women, there has been a consistent or even increased occurrence of endometrial and ovarian cancers; conversely, prostate cancer remains one of the most diagnosed malignancies, with a rise in reported cases, partly due to enhanced and improved screening efforts.Simultaneously, the landscape of cancer therapeutics has undergone a remarkable evolution, encompassing the introduction of targeted therapies and significant advancements in traditional chemotherapy. Modern targeted treatments aim to selectively address the molecular aberrations driving cancer, minimizing adverse effects on normal cells. However, traditional chemotherapy retains its crucial role, offering a broad-spectrum approach that, despite its wider range of side effects, remains indispensable in the treatment of various cancers, often working synergistically with targeted therapies to enhance overall efficacy.For urogenital cancers, especially ovarian and prostate cancers, DNA damage response inhibitors, such as PARP inhibitors, have emerged as promising therapeutic avenues. In BRCA-mutated ovarian cancer, PARP inhibitors like olaparib and niraparib have demonstrated efficacy, leading to their approval for specific indications. Similarly, patients with DNA damage response mutations have shown sensitivity to these agents in prostate cancer, heralding a new frontier in disease management. Furthermore, the progression of ovarian and prostate cancer is intricately linked to hormonal regulation. Ovarian cancer development has also been associated with prolonged exposure to estrogen, while testosterone and its metabolite dihydrotestosterone, can fuel the growth of prostate cancer cells. Thus, understanding the interplay between hormones, DNA damage and repair mechanisms can hold promise for exploring novel targeted therapies for ovarian and prostate tumors.In addition, it is of primary importance the use of preclinical models that mirror as close as possible the biological and genetic features of patients' tumors in order to effectively translate novel therapeutic findings "from the bench to the bedside".In summary, the complex landscape of urogenital cancers underscores the need for innovative approaches. Targeted therapy tailored to DNA repair mechanisms and hormone regulation might offer promising avenues for improving the management and outcomes for patients affected by ovarian and prostate cancers.

Acetylated KHSRP impairs DNA-damage-response-related mRNA decay and facilitates prostate cancer tumorigenesis

Androgen-regulated DNA damage response (DDR) is one of the essential mechanisms in prostate cancer (PCa), a hormone-sensitive disease. The heterogeneous nuclear ribonucleoprotein K (hnRNPK)-homology splicing regulatory protein known as far upstream element-binding protein 2 (KHSRP) is an RNA-binding protein that can attach to AU-rich elements in the 3' untranslated region (3'-UTR) of messenger RNAs (mRNAs) to mediate mRNA decay and emerges as a critical regulator in the DDR to preserve genome integrity. Nevertheless, how KHSRP responds to androgen-regulated DDR in PCa development remains unclear. This study found that androgen can significantly induce acetylation of KHSRP, which intrinsically drives tumor growth in xenografted mice. Moreover, enhanced KHSRP acetylation upon androgen stimuli impedes KHSRP-regulated DDR gene expression, as seen by analyzing RNA sequencing (RNA-seq) and Gene Set Enrichment Analysis (GSEA) datasets. Additionally, NAD-dependent protein deacetylase sirtuin-7 (SIRT7) is a promising deacetylase of KHSRP, and androgen stimuli impairs its interaction with KHSRP to sustain the increased KHSRP acetylation level in PCa. We first report the acetylation of KHSRP induced by androgen, which interrupts the KHSRP-regulated mRNA decay of the DDR-related genes to promote the tumorigenesis of PCa. This study provides insight into KHSRP biology and potential therapeutic strategies for PCa treatment, particularly that of castration-resistant PCa.

DNA Damage Response and Mismatch Repair Gene Defects in Advanced and Metastatic Prostate Cancer

Alterations in DNA damage response (DDR) and related genes are present in up to 25% of advanced prostate cancers (PCa). Most frequently altered genes are involved in the homologous recombination repair, the Fanconi anemia, and the mismatch repair pathways, and their deficiencies lead to a highly heterogeneous spectrum of DDR-deficient phenotypes. More than half of these alterations concern non- BRCA DDR genes. From a therapeutic perspective, poly-ADP-ribose polymerase inhibitors have demonstrated robust clinical efficacy in tumors with BRCA2 and BRCA1 alterations. Mismatch repair-deficient PCa, and a subset of CDK12-deficient PCa, are vulnerable to immune checkpoint inhibitors. Emerging data point to the efficacy of ATR inhibitors in PCa with ATM deficiencies. Still, therapeutic implications are insufficiently clarified for most of the non- BRCA DDR alterations, and no successful targeted treatment options have been established.

A novel approach to evaluation of tumor response for advanced pulmonary adenocarcinoma using the intertumoral heterogeneity response score

Treatment response and prognosis estimation in advanced pulmonary adenocarcinoma are challenged by the significant heterogeneity of the disease. The current Response Evaluation Criteria in Solid Tumors (RECIST) criteria, despite providing a basis for solid tumor response evaluation, do not fully encompass this heterogeneity. To better represent these nuances, we introduce the intertumoral heterogeneity response score (THRscore), a measure built upon and expanding the RECIST criteria. This retrospective study included patients with 3-10 measurable advanced lung adenocarcinoma lesions who underwent first-line chemotherapy or targeted therapy. The THRscore, derived from the coefficient of variation in size for each measurable tumor before and 4-6 weeks posttreatment, unveiled a correlation with patient outcomes. Specifically, a high THRscore was associated with shorter progression-free survival, lower tumor response rate, and a higher tumor mutation burden. These associations were further validated in an external cohort, confirming THRscore's effectiveness in stratifying patients based on progression risk and treatment response, and enhancing the utility of RECIST in capturing complex tumor behaviors in lung adenocarcinoma. These findings affirm the promise of THRscore as an enhanced tool for tumor response assessment in advanced lung adenocarcinoma, extending the RECIST criteria's utility.

Prostate-Specific Membrane Antigen-Targeted Therapies for Prostate Cancer: Towards Improving Therapeutic Outcomes

CONTEXT

Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein overexpressed in most prostate cancers and exploited as a target for PSMA-targeted therapies. Different approaches to target PSMA-expressing cancer cells have been developed, showing promising results in clinical trials.

OBJECTIVE

To discuss the regulation of PSMA expression and the main PSMA-targeted therapeutic concepts illustrating their clinical development and rationalizing combination approaches with examples.

EVIDENCE ACQUISITION

We performed a detailed literature search using PubMed and reviewed the American Society of Clinical Oncology and European Society of Medical Oncology annual meeting abstracts up to September 2023.

EVIDENCE SYNTHESIS

We present an overarching description of the different strategies to target PSMA. The outcomes of PSMA-targeted therapies strongly rely on surface-bound PSMA expression. However, PSMA heterogeneity at different levels (interpatient and inter/intratumoral) limits the efficacy of PSMA-targeted therapies. We highlight the molecular mechanisms governing PSMA regulation, the understanding of which is crucial to designing therapeutic strategies aimed at upregulating PSMA expression. Thus far, homeobox B13 (HOXB13) and androgen receptor (AR) have emerged as critical transcription factors positively and negatively regulating PSMA expression, respectively. Furthermore, epigenetic regulation of PSMA has been also reported recently. In addition, many established therapeutic approaches harbor the potential to upregulate PSMA levels as well as potentiate DNA damage mediated by current radioligands.

CONCLUSIONS

PSMA-targeted therapies are rapidly advancing, but their efficacy is strongly limited by the heterogeneous expression of the target. A thorough comprehension of how PSMA is regulated will help improve the outcomes through increasing PSMA expression and will provide the basis for synergistic combination therapies.

PATIENT SUMMARY

Prostate-specific membrane antigen (PSMA) is overexpressed in most prostate cancers. PSMA-targeted therapies have shown promising results, but the heterogeneous expression of PSMA limits their efficacy. We propose to better elucidate the regulation of PSMA expression to increase the levels of the target and improve the therapeutic outcomes.

Structure based docking and biological evaluation towards exploring potential anti-cancerous and apoptotic activity of 6-Gingerol against human prostate carcinoma cells

BACKGROUND

6-Gingerol (6-G) is the primary active phytocomponent of ginger and has been shown to regulate multiple targets against cancer and its treatment. Androgen receptors (ARs) remain critical in the progression of prostate cancer (PCa). This study focuses on investigating 6-G as a promising anti-cancerous agent that inhibits AR activity significantly.

METHODS

In this study, molecular docking simulation was done to investigate the binding affinity of 6-G and control drug Bicalutamide (BT) against oncogenic AR and tumor suppressor estrogen receptor β (ERβ). The crystal structure of AR and ERβ was retrieved from Protein Data Bank (PDB) and docked with 3D Pubchem structures of 6-G using iGEMDOCK and AutoDock. Further in vitro study was done to evaluate the antioxidant, anti-cancerous, apoptotic, and wound healing potential of 6-G.

RESULTS

The result displays that 6-G shows good binding affinity with AR and ERβ. Condensation of the nucleus, change in mitochondrial membrane potential (MMP) and the ability to induce reactive oxygen species (ROS) were done in human PCa PC-3 cells. Results from the MTT assay demonstrated that 6-G and control drug BT showed significant (p < 0.01) dose and time dependent inhibition of human PCa PC-3 cells. 6-G increased the ROS generation intracellularly and decreased the MMP, and cell migration in treated PCa PC-3 cells. 6-G treated cells showed fragmented, condensed chromatin and nuclear apoptotic bodies.

CONCLUSIONS

Thus, this study validates 6-G as a potential drug candidate against human PCa. However, further study of the anticancer potency of 6-G has to be done before its use for PCa treatment.

Effect of ubiquitin protease system on DNA damage response in prostate cancer (Review)

Genomic instability is an essential hallmark of cancer, and cellular DNA damage response (DDR) defects drive tumorigenesis by disrupting genomic stability. Several studies have identified abnormalities in DDR-associated genes, and a dysfunctional ubiquitin-proteasome system (UPS) is the most common molecular event in metastatic castration-resistant prostate cancer (PCa). For example, mutations in Speckle-type BTB/POZ protein-Ser119 result in DDR downstream target activation deficiency. Skp2 excessive upregulation inhibits homologous recombination repair and promotes cell growth and migration. Abnormally high expression of a deubiquitination enzyme, ubiquitin-specific protease 12, stabilizes E3 ligase MDM2, which further leads to p53 degradation, causing DDR interruption and genomic instability. In the present review, the basic pathways of DDR, UPS dysfunction, and its induced DDR alterations mediated by genomic instability, and especially the potential application of UPS and DDR alterations as biomarkers and therapeutic targets in PCa treatment, were described.

Metabolic Adaptation and Cellular Stress Response As Targets for Cancer Therapy

Cancer cells, which divide indefinitely and without control, are frequently exposed to various stress factors but manage to adapt and survive. The mechanisms by which cancer cells maintain cellular homeostasis and exploit stress conditions are not yet clear. Here, we elucidate the roles of diverse cellular metabolism and its regulatory mechanisms, highlighting the essential role of metabolism in cellular composition and signal transduction. Cells respond to various stresses, including DNA damage, energy stress, and oxidative stress, thereby causing metabolic alteration. We provide profound insight into the adaptive mechanisms employed by cancer cells to ensure their survival among internal and external stressors through a comprehensive analysis of the correlation between metabolic alterations and cellular stress. Furthermore, this research establishes a robust framework for the development of innovative therapeutic strategies that specifically target the cellular adaptations of cancer cells.

Identifying diseases associated with Post-COVID syndrome through an integrated network biology approach

A growing body of research shows that COVID-19 is now recognized as a multi-organ disease with a wide range of manifestations that can have long-lasting repercussions, referred to as post-COVID-19 syndrome. It is unknown why the vast majority of COVID-19 patients develop post-COVID-19 syndrome, or why patients with pre-existing disorders are more likely to experience severe COVID-19. This study used an integrated network biology approach to obtain a comprehensive understanding of the relationship between COVID-19 and other disorders. The approach involved building a PPI network with COVID-19 genes and identifying highly interconnected regions. The molecular information contained within these subnetworks, as well as the pathway annotations, were used to reveal the link between COVID-19 and other disorders. Using Fisher's exact test and disease-specific gene information, significant COVID-19-disease associations were discovered. The study discovered diseases that affect multiple organs and organ systems, thus proving the theory of multiple organ damage caused by COVID-19. Cancers, neurological disorders, hepatic diseases, cardiac disorders, pulmonary diseases, and hypertensive diseases are just a few of the conditions linked to COVID-19. Pathway enrichment analysis of shared proteins revealed the shared molecular mechanism of COVID-19 and these diseases. The findings of the study shed new light on the major COVID-19-associated disease conditions and how their molecular mechanisms interact with COVID-19. The novelty of studying disease associations in the context of COVID-19 provides new insights into the management of rapidly evolving long-COVID and post-COVID syndromes, which have significant global implications.Communicated by Ramaswamy H. Sarma.

Exploiting the DNA Damage Response for Prostate Cancer Therapy

Prostate cancers that progress despite androgen deprivation develop into castration-resistant prostate cancer, a fatal disease with few treatment options. In this review, we discuss the current understanding of prostate cancer subtypes and alterations in the DNA damage response (DDR) that can predispose to the development of prostate cancer and affect its progression. We identify barriers to conventional treatments, such as radiotherapy, and discuss the development of new therapies, many of which target the DDR or take advantage of recurring genetic alterations in the DDR. We place this in the context of advances in understanding the genetic variation and immune landscape of CRPC that could help guide their use in future treatment strategies. Finally, we discuss several new and emerging agents that may advance the treatment of lethal disease, highlighting selected clinical trials.

High Risk of Heart Tumors after COVID-19

An emergence of evidence suggests that severe COVID-19 is associated with an increased risk of developing breast and gastrointestinal cancers. The aim of this research was to assess the risk of heart tumors development in patients who have had COVID-19.

METHODS

A comparative analysis of 173 heart tumors was conducted between 2016 and 2023. Immunohistochemical examination with antibodies against spike SARS-CoV-2 was performed on 21 heart tumors: 10 myxomas operated before 2020 (the control group), four cardiac myxomas, one proliferating myxoma, three papillary fibroelastomas, two myxofibrosarcomas, one chondrosarcoma resected in 2022-2023. Immunohistochemical analysis with antibodies against CD34 and CD68 was also conducted on the same 11 Post-COVID period heart tumors. Immunofluorescent examination with a cocktail of antibodies against spike SARS-CoV-2/CD34 and spike SARS-CoV-2/CD68 was performed in 2 cases out of 11 (proliferating myxoma and classic myxoma).

RESULTS

A 1.5-fold increase in the number of heart tumors by 2023 was observed, with a statistically significant increase in the number of myxomas. There was no correlation with vaccination, and no significant differences were found between patients from 2016-2019 and 2021-2023 in terms of gender, age, and cardiac rhythm dis-orders. Morphological examination revealed the expression of spike SARS-CoV-2 in tumor cells, endothelial cells, and macrophages in 10 out of 11 heart tumors.

CONCLUSION

The detection of SARS-CoV-2 persistence in endothelium and macrophages as well as in tumor cells of benign and malignant cardiac neoplasms, the increase in the number of these tumors, especially cardiac myxomas, after the pandemic by 2023 may indicate a trend toward an increased risk of cardiac neoplasms in COVID-19 patients, which re-quires further research on this issue and a search for new evidence.

Androgen receptor contributes to repairing DNA damage induced by inflammation and oxidative stress in prostate cancer

Background

Androgen deprivation therapy remains the first-line therapy option for prostate cancer, mostly resulting in the transition of the disease to a castration-resistant state. The lack of androgen signaling during therapy affects various cellular processes, which sometimes paradoxically contributes to cancer progression. As androgen receptor (AR) signaling is known to contribute to oxidative stress regulation, loss of AR may also affect DNA damage level and the response mechanism in oxidant and inflammatory conditions of the prostate tumor microenvironment. Therefore, this study aimed to investigate the role of AR and AR-regulated tumor suppressor NKX3.1 upon oxidative stress-induced DNA damage response (DDR) in the inflammatory tumor microenvironment of the prostate.

Materials and methods

Intracellular reactive oxygen species (ROS) level was induced by either inflammatory conditioned media obtained from lipopolysaccharide-induced macrophages or oxidants and measured by dichlorodihydrofluorescein diacetate. In addition to this, DNA damage was subsequently quantified by counting gH2AX foci using an immunofluorescence-based Aklides platform. Altered expression of proteins function in DDR detected by western blotting.

Results

Cellular levels of ROS and ROS-induced DNA double-strand break damage were analyzed in the absence and presence of AR signaling upon treatment of prostate cancer cells by either oxidants or inflammatory microenvironment exposure. The results showed that AR suppresses intracellular ROS and contributes to DNA damage recognition under oxidant conditions. Besides, increased DNA damage due to loss of NKX3.1 under inflammatory conditions was alleviated by its overexpression. Moreover, the activation of the DDR mediators caused by AR and NKX3.1 activation in androgen-responsive and castration-resistant prostate cancer cells indicated that the androgen receptor function is essential both in controlling oxidative stress and in activating the ROS-induced DDR.

Conclusion

Taken together, it is concluded that the regulatory function of androgen receptor signaling has a vital function in the balance between antioxidant response and DDR activation.

Current advances of liquid biopsies in prostate cancer: Molecular biomarkers

Prostate cancer (PCa) incidence is increasing and endangers men's lives. Early detection of PCa could improve overall survival (OS) by preventing metastasis. The prostate-specific antigen (PSA) test is a popular screening method. Several advisory groups, however, warn against using the PSA test due to its high false positive rate, unsupported outcome, and limited benefit. The number of disease-related biopsies performed annually far outweighs the number of diagnoses. Thus, there is an urgent need to develop accurate diagnostic biomarkers to detect PCa and distinguish between aggressive and indolent cancers. Recently, non-coding RNA (ncRNA), circulating tumor DNA (ctDNA)/ctRNA, exosomes, and metabolomic biomarkers in the liquid biopsies (LBs) of patients with PCa showed significant differences and clinical benefits in diagnosis, prognosis, and monitoring response to therapy. The analysis of urinary exosomal ncRNA presented a substantial correlation among Exos-miR-375 downregulation, clinical T stage, and bone metastases of PCa. Furthermore, the expression of miR-532-5p in urine samples was a vital predictive biomarker of PCa progression. Thus, this review focuses on promising molecular and metabolomic biomarkers in LBs from patients with PCa. We thoroughly addressed the most recent clinical findings of LB biomarker use in diagnosing and monitoring PCa in early and advanced stages.

Antioxidative stress protein SRXN1 can be used as a radiotherapy prognostic marker for prostate cancer

PURPOSE

To explore the mechanisms of radiotherapy resistance and search for prognostic biomarkers for prostate cancer.

METHODS

The GSE192817 and TCGA PRAD datasets were selected and downloaded from the GEO and UCSC Xena databases. Differential expression and functional annotation analyses were applied to 52 tumour cell samples from GSE192817. Then, the ssGSEA or GSVA algorithms were applied to quantitatively score the biological functional activity of samples in the GSE192817 and TCGA PRAD datasets, combined with specific gene sets collected from the Molecular Signatures Database (MSigDB). Subsequently, the Wilcoxon rank-sum test was used to compare the differences in ssGSEA or GSVA scores among cell types or PRAD patients. Moreover, radiotherapy resistance-associated gene screening was performed on DU145 and PC3 cells (prostate cancer cells), and survival analysis was used to evaluate the efficacy of these genes for predicting the prognosis of PRAD patients.

RESULTS

A total of 114 genes that were differentially expressed in more than two different cancer cell types and associated with either sham surgery or radiotherapy treatment (X-ray or photon irradiation) were detected in cancer cells from GSE192817. Comparison of DNA damage-related ssGSEA scores between sham surgery and radiotherapy treatment in prostate cancer cells (DU145 and PC3) showed that photon irradiation was potentially more effective than X-ray treatment. In the TCGA PRAD dataset, patients treated with radiotherapy had much higher "GOBP_CELLULAR_RESPONSE_TO_DNA_DAMAGE_STIMULUS", "GOBP_G2_DNA_DAMAGE_CHECKPOINT" and "GOBP_INTRA_S_DNA_DAMAGE_CHECKPOINT" GSVA scores, and the Wilcoxon rank-sum test p values were 0.0005, 0.0062 and 0.0800, respectively. Furthermore, SRXN1 was upregulated in DU145 cells (resistant to X-ray irradiation compared to PC3 cells) after radiotherapy treatment, and low SRXN1 expression in patients was beneficial to radiotherapy outcomes. The log-rank test p value for PFS was 0.0072.

CONCLUSIONS

Radiotherapy can damage DNA and induce oxidative stress to kill tumour cells. In this study, we found that SRXN1, as an antioxidative stress gene, plays an important role in radiotherapy for prostate cancer treatment, and this gene is also a potential biomarker for predicting the prognosis of patients treated with radiotherapy.

Targeting Prostate Cancer, the 'Tousled Way'

Androgen deprivation therapy (ADT) has been the mainstay of prostate cancer (PCa) treatment, with success in developing more effective inhibitors of androgen synthesis and antiandrogens in clinical practice. However, hormone deprivation and AR ablation have caused an increase in ADT-insensitive PCas associated with a poor prognosis. Resistance to ADT arises through various mechanisms, and most castration-resistant PCas still rely on the androgen axis, while others become truly androgen receptor (AR)-independent. Our research identified the human tousled-like kinase 1 (TLK1) as a crucial early mediator of PCa cell adaptation to ADT, promoting androgen-independent growth, inhibiting apoptosis, and facilitating cell motility and metastasis. Although explicit, the growing role of TLK1 biology in PCa has remained underrepresented and elusive. In this review, we aim to highlight the diverse functions of TLK1 in PCa, shed light on the molecular mechanisms underlying the transition from androgen-sensitive (AS) to an androgen-insensitive (AI) disease mediated by TLK1, and explore potential strategies to counteract this process. Targeting TLK1 and its associated signaling could prevent PCa progression to the incurable metastatic castration-resistant PCa (mCRPC) stage and provide a promising approach to treating PCa.

Recent Research Advances in Double-Strand Break and Mismatch Repair Defects in Prostate Cancer and Potential Clinical Applications

Prostate cancer remains a leading cause of cancer-related death in men worldwide. Recent research advances have emphasized the critical roles of mismatch repair (MMR) and double-strand break (DSB) in prostate cancer development and progression. Here, we provide a comprehensive review of the molecular mechanisms underlying DSB and MMR defects in prostate cancer, as well as their clinical implications. Furthermore, we discuss the promising therapeutic potential of immune checkpoint inhibitors and PARP inhibitors in targeting these defects, particularly in the context of personalized medicine and further perspectives. Recent clinical trials have demonstrated the efficacy of these novel treatments, including Food and Drugs Association (FDA) drug approvals, offering hope for improved patient outcomes. Overall, this review emphasizes the importance of understanding the interplay between MMR and DSB defects in prostate cancer to develop innovative and effective therapeutic strategies for patients.

The epigenetic function of androgen receptor in prostate cancer progression

Androgen and androgen deprivation (castration) therapies, including androgen receptor antagonists, are clinically used to treat patients with prostate cancer. However, most hormone-dependent prostate cancer patients progress into a malignant state with loss of hormone-dependency, known as castration (drug)-resistant prostate cancer (CRPC), after prolong androgen-based treatments. Even in the CRPC state with irreversible malignancy, androgen receptor (AR) expression is detectable. An epigenetic transition to CRPC induced by the action of AR-mediated androgen could be speculated in the patients with prostate cancer. Androgen receptors belongs to the nuclear receptor superfamily with 48 members in humans, and acts as a ligand-dependent transcriptional factor, leading to local chromatin reorganization for ligand-dependent gene regulation. In this review, we discussed the transcriptional/epigenetic regulatory functions of AR, with emphasis on the clinical applications of AR ligands, AR protein co-regulators, and AR RNA coregulator (enhancer RNA), especially in chromatin reorganization, in patients with prostate cancer.

Cytotoxicity Mechanisms of Eight Major Herbicide Active Ingredients in Comparison to Their Commercial Formulations

Commercial pesticide formulations contain co-formulants, which are generally considered as having no toxic effects in mammals. This study aims to compare the toxicity of 8 major herbicide active ingredients-namely glyphosate, dicamba, 2,4-D, fluroxypyr, quizalofop-p-ethyl, pendimethalin, propyzamide and metazachlor-with a typical commercial formulation of each active ingredient. Cytotoxicity and oxidative stress capability was assessed in human hepatoma HepG2 cells. Using an MTT assay, formulations of glyphosate (Roundup Probio), fluroxypyr (Hurler), quizalofop-p-ethyl (Targa Super) and dicamba (Hunter) were more toxic than the active ingredient alone. Metazachlor and its formulation Sultan had similar cytotoxicity profiles. Cytotoxicity profiles were comparable in immortalised human fibroblasts. Toxilight necrosis assays showed the formulation of metazachlor (Sultan50C) resulted in significant membrane disruption compared to the active ingredient. Generation of reactive oxygen species was detected for glyphosate, fluroxypyr, pendimethalin, quizalofop-p-ethyl, the formulation of 2,4-D (Anti-Liserons), and dicamba and its formulation Hunter. Further testing of quizalofop-p-ethyl and its formulation Targa Super in the ToxTracker assay system revealed that both products induced oxidative stress and an unfolded protein response. In conclusion, these results show that most herbicide formulations tested in this study are more toxic than their active ingredients in human tissue culture cell model systems. The results add to a growing body of evidence, which implies that commercial herbicide formulations and not just their active ingredients should be evaluated in regulatory risk assessment of pesticides.

Role of Olaparib in the Management of Metastatic Castration-Resistant Prostate Cancer: A Japanese Clinician's Perspective

Several studies have identified various targetable genomic alterations in prostate cancer, which accumulate during carcinogenesis and cancer progression. Genomic alterations in genes involved in DNA damage repair by homologous recombination repair may predict increased sensitivity to poly-ADP ribose polymerase (PARP) inhibitors. The Phase 3 PROfound trial has shown that treatment with the PARP inhibitor olaparib was associated with an improved radiographic progression-free survival and overall survival among patients with homologous recombination repair-deficient metastatic castration-resistant prostate cancer (mCRPC) after the treatment with androgen receptor targeting therapy, especially in men with BRCA1 or BRCA2 mutation. In Japan, olaparib was approved in December 2020 for the treatment of mCRPC with BRCA1 or BRCA2 mutation. In addition, genetic tests to detect BRCA1 or BRCA2 mutation to select patients who are likely to benefit from olaparib were also approved. This review summarizes the status of olaparib treatment for mCRPC, focusing on the situation in Japan.

Interplay of Developmental Hippo-Notch Signaling Pathways with the DNA Damage Response in Prostate Cancer

Prostate cancer belongs in the class of hormone-dependent cancers, representing a major cause of cancer incidence in men worldwide. Since upon disease onset almost all prostate cancers are androgen-dependent and require active androgen receptor (AR) signaling for their survival, the primary treatment approach has for decades relied on inhibition of the AR pathway via androgen deprivation therapy (ADT). However, following this line of treatment, cancer cell pools often become resistant to therapy, contributing to disease progression towards the significantly more aggressive castration-resistant prostate cancer (CRPC) form, characterized by poor prognosis. It is, therefore, of critical importance to elucidate the molecular mechanisms and signaling pathways underlying the progression of early-stage prostate cancer towards CRPC. In this review, we aim to shed light on the role of major signaling pathways including the DNA damage response (DDR) and the developmental Hippo and Notch pathways in prostate tumorigenesis. We recapitulate key evidence demonstrating the crosstalk of those pathways as well as with pivotal prostate cancer-related 'hubs' such as AR signaling, and evaluate the clinical impact of those interactions. Moreover, we attempt to identify molecules of the complex DDR-Hippo-Notch interplay comprising potentially novel therapeutic targets in the battle against prostate tumorigenesis.

From Omics to Multi-Omics Approaches for In-Depth Analysis of the Molecular Mechanisms of Prostate Cancer

Cancer arises following alterations at different cellular levels, including genetic and epigenetic modifications, transcription and translation dysregulation, as well as metabolic variations. High-throughput omics technologies that allow one to identify and quantify processes involved in these changes are now available and have been instrumental in generating a wealth of steadily increasing data from patient tumors, liquid biopsies, and from tumor models. Extensive investigation and integration of these data have led to new biological insights into the origin and development of multiple cancer types and helped to unravel the molecular networks underlying this complex pathology. The comprehensive and quantitative analysis of a molecule class in a biological sample is named omics and large-scale omics studies addressing different prostate cancer stages have been performed in recent years. Prostate tumors represent the second leading cancer type and a prevalent cause of cancer death in men worldwide. It is a very heterogenous disease so that evaluating inter- and intra-tumor differences will be essential for a precise insight into disease development and plasticity, but also for the development of personalized therapies. There is ample evidence for the key role of the androgen receptor, a steroid hormone-activated transcription factor, in driving early and late stages of the disease, and this led to the development and approval of drugs addressing diverse targets along this pathway. Early genomic and transcriptomic studies have allowed one to determine the genes involved in prostate cancer and regulated by androgen signaling or other tumor-relevant signaling pathways. More recently, they have been supplemented by epigenomic, cistromic, proteomic and metabolomic analyses, thus, increasing our knowledge on the intricate mechanisms involved, the various levels of regulation and their interplay. The comprehensive investigation of these omics approaches and their integration into multi-omics analyses have led to a much deeper understanding of the molecular pathways involved in prostate cancer progression, and in response and resistance to therapies. This brings the hope that novel vulnerabilities will be identified, that existing therapies will be more beneficial by targeting the patient population likely to respond best, and that bespoke treatments with increased efficacy will be available soon.

Tousled-like kinase 1: a novel factor with multifaceted role in mCRPC progression and development of therapy resistance

Standard treatment for advanced Prostate Cancer (PCa) consists of androgen deprivation therapy (ADT), but ultimately fails, resulting in the incurable phase of the disease: metastatic castration-resistant prostate cancer (mCRPC). Targeting PCa cells before their progression to mCRPC would greatly improve the outcome, if strategies could be devised selectively targeting androgen receptor (AR)-dependent and/or independent compensatory pathways which promote mCRPC development. Combination therapy by targeting the DNA damage response (DDR) along with ADT has been limited by general toxicity, and a goal of clinical trials is how to target the DDR more specifically. In recent years, our lab has identified a key role for the DDR kinase, TLK1, in mediating key aspects of adaptation to ADT, first by promoting a cell cycle arrest (through the TLK1>NEK1>ATR>Chk1 kinase cascade) under the unfavorable growth conditions (androgen deprivation), and then by reprogramming the PCa cells to adapt to androgen-independent growth via the NEK1>YAP/AR>CRPC conversion. In addition, TLK1 plays a key anti-apoptotic role via the NEK1>VDAC1 regulation on the intrinsic mitochondrial apoptotic pathway when the DDR is activated. Finally, TLK1 was recently identified as having an important role in motility and metastasis via regulation of the kinases MK5/PRAK and AKT (indirectly via AKTIP).

BRCA Mutations in Prostate Cancer: Assessment, Implications and Treatment Considerations

Prostate cancer ranks fifth in cancer-related mortality in men worldwide. DNA damage is implicated in cancer and DNA damage response (DDR) pathways are in place against this to maintain genomic stability. Impaired DDR pathways play a role in prostate carcinogenesis and germline or somatic mutations in DDR genes have been found in both primary and metastatic prostate cancer. Among these, BRCA mutations have been found to be especially clinically relevant with a role for germline or somatic testing. Prostate cancer with DDR defects may be sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors which target proteins in a process called PARylation. Initially they were used to target BRCA-mutated tumor cells in a process of synthetic lethality. However, recent studies have found potential for PARP inhibitors in a variety of other genetic settings. In this review, we explore the mechanisms of DNA repair, potential for genomic analysis of prostate cancer and therapeutics of PARP inhibitors along with their safety profile.

Tissue- and Liquid-Based Biomarkers in Prostate Cancer Precision Medicine

Worldwide, prostate cancer (PC) is the second-most-frequently diagnosed male cancer and the fifth-most-common cause of all cancer-related deaths. Suspicion of PC in a patient is largely based upon clinical signs and the use of prostate-specific antigen (PSA) levels. Although PSA levels have been criticised for a lack of specificity, leading to PC over-diagnosis, it is still the most commonly used biomarker in PC management. Unfortunately, PC is extremely heterogeneous, and it can be difficult to stratify patients whose tumours are unlikely to progress from those that are aggressive and require treatment intensification. Although PC-specific biomarker research has previously focused on disease diagnosis, there is an unmet clinical need for novel prognostic, predictive and treatment response biomarkers that can be used to provide a precision medicine approach to PC management. In particular, the identification of biomarkers at the time of screening/diagnosis that can provide an indication of disease aggressiveness is perhaps the greatest current unmet clinical need in PC management. Largely through advances in genomic and proteomic techniques, exciting pre-clinical and clinical research is continuing to identify potential tissue, blood and urine-based PC-specific biomarkers that may in the future supplement or replace current standard practices. In this review, we describe how PC-specific biomarker research is progressing, including the evolution of PSA-based tests and those novel assays that have gained clinical approval. We also describe alternative diagnostic biomarkers to PSA, in addition to biomarkers that can predict PC aggressiveness and biomarkers that can predict response to certain therapies. We believe that novel biomarker research has the potential to make significant improvements to the clinical management of this disease in the near future.

Recognition of a tandem lesion by DNA bacterial formamidopyrimidine glycosylases explored combining molecular dynamics and machine learning

The combination of several closely spaced DNA lesions, which can be induced by a single radical hit, constitutes a hallmark in the DNA damage landscape and radiation chemistry. The occurrence of such a tandem base lesion gives rise to a strong coupling with the double helix degrees of freedom and induces important structural deformations, in contrast to DNA strands containing a single oxidized nucleobase. Although such complex lesions are known to be refractory to repair by DNA glycosylases, there is still a lack of structural evidence to rationalize these phenomena. In this contribution, we explore, by numerical modeling and molecular simulations, the behavior of the bacterial glycosylase responsible for base excision repair (MutM), specialized in excising oxidatively-damaged defects such as 7,8-dihydro-8-oxoguanine (8-oxoG). The difference in lesion recognition between a simple damage and a tandem lesion featuring an additional abasic site is assessed at atomistic resolution owing to microsecond molecular dynamics simulations and machine learning postprocessing, allowing to extensively pinpoint crucial differences in the interaction patterns of the damaged bases. Our results reveal substantial changes in the interaction network surrounding the 8-oxoG upon addition of an adjacent abasic site, leading to the perturbation of the intercalation triad which is crucial for lesion recognition and processing. The recognition process might also be impacted by a more constrained MutM-DNA binding upon tandem damage, as shown by the machine learning post-processing. This work advocates for the use of such high throughput numerical simulations for exploring the complex combinatorial chemistry of tandem DNA lesions repair and more generally local multiple damaged sites of the utmost significance in radiation chemistry.

Cancer as a prospective sequela of long COVID-19

As the spread of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) continues to surge worldwide, our knowledge of coronavirus disease 2019 (COVID‐19) is rapidly expanding. Although most COVID‐19 patients recover within weeks of symptom onset, some experience lingering symptoms that last for months (“long COVID‐19”). Early reports of COVID‐19 sequelae, including cardiovascular, pulmonary, and neurological conditions, have raised concerns about the long‐term effects of COVID‐19, especially in hard‐hit communities. It is becoming increasingly evident that cancer patients are more susceptible to SARS‐CoV‐2 infection and are at a higher risk of severe COVID‐19 than the general population. Nevertheless, whether long COVID‐19 increases the risk of cancer in those with no prior malignancies, remains unclear. Given, the disproportionate impact of the disease on the African American community, yet another unanswered question is whether racial disparities are to be expected in COVID‐19 sequelae. Herein, we propose that long COVID‐19 may predispose recovered patients to cancer development and accelerate cancer progression. This hypothesis is based on growing evidence of the ability of SARS‐CoV‐2 to modulate oncogenic pathways, promote chronic low‐grade inflammation, and cause tissue damage. Comprehensive studies are urgently required to elucidate the effects of long COVID‐19 on cancer susceptibility.

The Hallmarks of Flavonoids in Cancer

Flavonoids represent an important group of bioactive compounds derived from plant-based foods and beverages with known biological activity in cells. From the modulation of inflammation to the inhibition of cell proliferation, flavonoids have been described as important therapeutic adjuvants against several diseases, including diabetes, arteriosclerosis, neurological disorders, and cancer. Cancer is a complex and multifactor disease that has been studied for years however, its prevention is still one of the best known and efficient factors impacting the epidemiology of the disease. In the molecular and cellular context, some of the mechanisms underlying the oncogenesis and the progression of the disease are understood, known as the hallmarks of cancer. In this text, we review important molecular signaling pathways, including inflammation, immunity, redox metabolism, cell growth, autophagy, apoptosis, and cell cycle, and analyze the known mechanisms of action of flavonoids in cancer. The current literature provides enough evidence supporting that flavonoids may be important adjuvants in cancer therapy, highlighting the importance of healthy and balanced diets to prevent the onset and progression of the disease.

The Tumor Microenvironment and Immunotherapy in Prostate and Bladder Cancer

Bladder cancer has been successfully treated with immunotherapy, whereas prostate cancer is a cold tumor with inadequate immune-related treatment response. A greater understanding of the tumor microenvironment and methods for harnessing the immune system to address tumor growth will be needed to improve immunotherapies for both prostate and bladder cancer. Here, we provide an overview of prostate and bladder cancer, including fundamental aspects of the disease and treatment, the elaborate cellular makeup of the tumor microenvironment, and methods for exploiting relevant pathways to develop more effective treatments.

Targeting DNA Damage Response in Prostate and Breast Cancer

Steroid hormone signaling induces vast gene expression programs which necessitate the local formation of transcription factories at regulatory regions and large-scale alterations of the genome architecture to allow communication among distantly related cis-acting regions. This involves major stress at the genomic DNA level. Transcriptionally active regions are generally instable and prone to breakage due to the torsional stress and local depletion of nucleosomes that make DNA more accessible to damaging agents. A dedicated DNA damage response (DDR) is therefore essential to maintain genome integrity at these exposed regions. The DDR is a complex network involving DNA damage sensor proteins, such as the poly(ADP-ribose) polymerase 1 (PARP-1), the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), the ataxia-telangiectasia-mutated (ATM) kinase and the ATM and Rad3-related (ATR) kinase, as central regulators. The tight interplay between the DDR and steroid hormone receptors has been unraveled recently. Several DNA repair factors interact with the androgen and estrogen receptors and support their transcriptional functions. Conversely, both receptors directly control the expression of agents involved in the DDR. Impaired DDR is also exploited by tumors to acquire advantageous mutations. Cancer cells often harbor germline or somatic alterations in DDR genes, and their association with disease outcome and treatment response led to intensive efforts towards identifying selective inhibitors targeting the major players in this process. The PARP-1 inhibitors are now approved for ovarian, breast, and prostate cancer with specific genomic alterations. Additional DDR-targeting agents are being evaluated in clinical studies either as single agents or in combination with treatments eliciting DNA damage (e.g., radiation therapy, including targeted radiotherapy, and chemotherapy) or addressing targets involved in maintenance of genome integrity. Recent preclinical and clinical findings made in addressing DNA repair dysfunction in hormone-dependent and -independent prostate and breast tumors are presented. Importantly, the combination of anti-hormonal therapy with DDR inhibition or with radiation has the potential to enhance efficacy but still needs further investigation.

Novel functions of cytoplasmic aminoacyl-tRNA synthetases shaping the hallmarks of cancer

With the intense protein synthesis demands of cancer, the classical enzymatic role of aminoacyl-tRNA synthetases (aaRSs) is required to sustain tumor growth. However, many if not all aaRSs also possess regulatory functions outside of the domain of catalytic tRNA aminoacylation, which can further contribute to or even antagonize cancers in non-translational ways. These regulatory functions of aaRS are likely to be manipulated in cancer to ensure uncontrolled growth and survival. This review will largely focus on the unique capacities of individual and sometimes collaborating synthetases to influence the hallmarks of cancer, which represent the principles and characteristics of tumorigenesis. An interesting feature of cytoplasmic aaRSs in higher eukaryotes is the formation of a large multi-synthetase complex (MSC) with nine aaRSs held together by three non-enzymatic scaffolding proteins (AIMPs). The MSC-associated aaRSs, when released from the complex in response to certain stimulations, often participate in pathways that promote tumorigenesis. In contrast, the freestanding aaRSs are associated with activities in both directions-some promoting while others inhibiting cancer. The AIMPs have emerged as potent tumor suppressors through their own distinct mechanisms. We propose that the tumor-suppressive roles of AIMPs may also be a consequence of keeping the cancer-promoting aaRSs within the MSC. The rich connections between cancer and the synthetases have inspired the development of innovative cancer treatments that target or take advantage of these novel functions of aaRSs.

Clinical potential of ATM inhibitors

The protein defective in the human genetic disorder ataxia-telangiectasia, ATM, plays a central role in responding to DNA double strand breaks and other lesions to protect the genome against DNA damage and in this way minimize the risk of mutations that can lead to abnormal cellular behaviour. Its function in normal cells is to protect the cell against genotoxic stress but inadvertently it can assist cancer cells by providing resistance against chemotherapeutic agents and thus favouring tumour growth and survival. However, it is now evident that ATM also functions in a DNA damage-independent fashion to protect the cell against other forms of stress such as oxidative and nutrient stress and this non-canonical mechanism may also be relevant to cancer susceptibility in individuals who lack a functional ATM gene. Thus the use of ATM inhibitors to combat resistance in tumours may extend beyond a role for this protein in the DNA damage response. Here, we provide some background on ATM and its activation and investigate the efficacy of ATM inhibitors in treating cancer.