Current opinion and mechanistic interpretation of combination therapy for castration-resistant prostate cancer

ACOX2 Serves as a Favorable Indicator Related to Lipid Metabolism and Oxidative Stress for Biochemical Recurrence in Prostate Cancer

Given the heterogeneity of tumors, there is an urgent need for accurate prognostic parameters in prostate cancer (PCa) patients. Lipid metabolism (LM) reprogramming and oxidative stress (OS) play a vital role in the progression of PCa. In this work, we identified five LM-OS-related genes (including ACOX2, PPRAGC1A, PTGS1, PTGS2, and HAO1) associated with the biochemical recurrence (BCR) of PCa. Subsequently, a prognostic signature was established based on these five genes. Kaplan-Meier survival estimates, receiver operating characteristic curves, and relationship analysis between risk score and clinical characters were applied to measure the robustness of the signature in an external cohort. A nomogram of risk score combined with clinical characteristics was constructed for clinical application. Functional enrichment analysis suggested that the underlying mechanism related to the signature included the calcium signaling, lipid transport, and cell cycle signaling pathways. Furthermore, WEE1 inhibitor was identified as a potential agent related to the cell cycle for high-risk patients. The mRNA expression and the prognostic value of the five genes were determined, and ACOX2 was identified as the key gene related to the prognostic signature. The protein expression of ACOX2 was measured in a prostate tissue microarray through an immunohistochemistry assay, confirming the bioinformatics results. By constructing the ACOX2-overexpressing PCa cell lines PC-3 and 22Rv1, the biological function of PCa cells was investigated. The cell viability, colony formation, migration, and invasion ability of PCa cell lines overexpressing ACOX2 were hindered. Decreased cellular lipid content and elevated cellular ROS content were observed in ACOX2-overexpressing PCa cell lines with reduced G2/M phases. In conclusion, this work presents the first prognostic signature specifically focused on LM-OS for PCa. ACOX2 could serve as a favorable indicator for the BCR in PCa. Further experiments are required to identify the potential underlying mechanism.

Anticancer Effect of Dihydroartemisinin via Dual Control of ROS-induced Apoptosis and Protective Autophagy in Prostate Cancer 22Rv1 Cells

BACKGROUND

Dihydroartemisinin (DHA), a natural agent, exhibits potent anticancer activity. However, its biological activity on prostate cancer (PCa) 22Rv1 cells has not been previously investigated.

OBJECTIVES

In this study, we demonstrate that DHA induces anticancer effects through the induction of apoptosis and autophagy.

METHODS

Cell viability and proliferation rate were assessed using the CCK-8 assay and cell clone formation assay. The generation of reactive oxygen species (ROS) was detected by flow cytometry. The molecular mechanism of DHA-induced apoptosis and autophagy was examined using Western blot and RT-qPCR. The formation of autophagosomes and the changes in autophagy flux were observed using transmission electron microscopy (TEM) and confocal microscopy. The effect of DHA combined with Chloroquine (CQ) was assessed using the EdU assay and flow cytometry. The expressions of ROS/AMPK/mTOR-related proteins were detected using Western blot. The interaction between Beclin-1 and Bcl-2 was examined using Co-IP.

RESULTS

DHA inhibited 22Rv1 cell proliferation and induced apoptosis. DHA exerted its antiprostate cancer effects by increasing ROS levels. DHA promoted autophagy progression in 22Rv1 cells. Inhibition of autophagy enhanced the pro-apoptotic effect of DHA. DHA-induced autophagy initiation depended on the ROS/AMPK/mTOR pathway. After DHA treatment, the impact of Beclin- 1 on Bcl-2 was weakened, and its binding with Vps34 was enhanced.

CONCLUSION

DHA induces apoptosis and autophagy in 22Rv1 cells. The underlying mechanism may involve the regulation of ROS/AMPK/mTOR signaling pathways and the interaction between Beclin-1 and Bcl-2 proteins. Additionally, the combination of DHA and CQ may enhance the efficacy of DHA in inhibiting tumor cell activity.

A review focusing on the role of pyroptosis in prostate cancer

As one of the types of programmed cell death, pyroptosis has become a focus of research in recent years. Numerous studies have shown that pyroptosis plays a regulatory role in tumor cell invasiveness, differentiation, proliferation, and metastasis. It has been demonstrated that pyroptosis is involved in the regulation of signaling pathways implicated in the pathogenesis of prostate cancer (PCa). Furthermore, the loss of expression of pyroptosis-related genes in PCa has been reported, and pyroptosis-related genes have demonstrated a considerable ability in predicting the prognosis of PCa. Therefore, the potential role of pyroptosis in regulating the development of PCa warrants further investigation and attention. In this review, we summarize the basics of the role of pyroptosis and also discuss research into the mechanisms of action associated with pyroptosis in PCa. It is hoped that by exploring the potential of the pyroptosis pathway in intervening in PCa, it will provide a viable direction for the diversification of PCa treatment.

Jumonji domain-containing protein RIOX2 is overexpressed and associated with worse survival outcomes in prostate cancers

Background

Histone demethylase RIOX2 was cloned as a c-Myc downstream gene involved in cell proliferation and has been implicated as an oncogenic factor in multiple tumor types. Its expression profiles and correlation with disease progression in prostate cancers are unknown.

Methods

Transcriptomic profiles of Jumanji domain-containing protein genes were assessed using multiple public expression datasets generated from RNA-seq and cDNA microarray assays. RIOX2 protein expression was assessed using an immunohistochemistry approach on a tissue section array from benign and malignant prostate tissues. Gene expression profiles were analyzed using the bioinformatics software R package. Western blot assay examined androgen stimulation on RIOX2 protein expression in LNCaP cells.

Results

Among 35 Jumanji domain-containing protein genes, 12 genes were significantly upregulated in prostate cancers compared to benign compartments. COX regression analysis identified that the ribosomal oxygenase 2 (RIOX2) gene was the only one significantly associated with disease-specific survival outcomes in prostate cancer patients. RIOX2 upregulation was confirmed at the protein levels using immunohistochemical assays on prostate cancer tissue sections. Meanwhile, RIOX2 upregulation was associated with clinicopathological features, including late-stage diseases, adverse Gleason scores, TP53 gene mutation, and disease-free status. In castration-resistant prostate cancers (CRPC), RIOX2 expression was positively correlated with AR signaling index but negatively correlated with the neuroendocrinal progression index. However, androgen treatment had no significant stimulatory effect on RIOX2 expression, indicating a parallel but not a causative effect of androgen signaling on RIOX2 gene expression. Further analysis discovered that RIOX2 expression was tightly correlated with its promoter hypomethylation and MYC gene expression, consistent with the notion that RIOX2 was a c-Myc target gene.

Conclusion

The Jumanji domain-containing protein RIOX2 was significantly overexpressed in prostate cancer, possibly due to c-Myc upregulation. RIOX2 upregulation was identified as an independent prognostic factor for disease-specific survival.

A combinational chemo-immune therapy using outer membrane vesicles for enhanced cancer therapy by RGD targeting

Cancer therapies are limited by poor drug penetration that impedes effective tumor treatment. This was overcome in the present study by loading the immune reaction inducing nanocarriers of the bacterial outer membrane vesicles (OMVs) and doxorubicin (DOX) into the natural immunity platform OMV via incubation. Drug accumulation at the tumor site was improved by using the targeting peptide 6-Mal- Arg-Gly-Asp (RGD) on the surface of OMVs to increase internalization via binding to cell surface integrin αvβ3. OMVs stimulate immune responses by reversing the immune-suppressive tumor microenvironment (TME) via decreasing TAM and Treg, increasing CD8+ T and M1, and promoting DC maturation. The combination of DOX and OMVs compensates for the shortcomings of monotherapy (e.g., chemotherapy and immunotherapy) and amplifies the therapeutic efficacy of cancer treatment, while aiding selection of novel nanocarriers and development of effective therapeutic regimens.

SYNPRED: prediction of drug combination effects in cancer using different synergy metrics and ensemble learning

Background

In cancer research, high-throughput screening technologies produce large amounts of multiomics data from different populations and cell types. However, analysis of such data encounters difficulties due to disease heterogeneity, further exacerbated by human biological complexity and genomic variability. The specific profile of cancer as a disease (or, more realistically, a set of diseases) urges the development of approaches that maximize the effect while minimizing the dosage of drugs. Now is the time to redefine the approach to drug discovery, bringing an artificial intelligence (AI)–powered informational view that integrates the relevant scientific fields and explores new territories.

Results

Here, we show SYNPRED, an interdisciplinary approach that leverages specifically designed ensembles of AI algorithms, as well as links omics and biophysical traits to predict anticancer drug synergy. It uses 5 reference models (Bliss, Highest Single Agent, Loewe, Zero Interaction Potency, and Combination Sensitivity Score), which, coupled with AI algorithms, allowed us to attain the ones with the best predictive performance and pinpoint the most appropriate reference model for synergy prediction, often overlooked in similar studies. By using an independent test set, SYNPRED exhibits state-of-the-art performance metrics either in the classification (accuracy, 0.85; precision, 0.91; recall, 0.90; area under the receiver operating characteristic, 0.80; and F1-score, 0.91) or in the regression models, mainly when using the Combination Sensitivity Score synergy reference model (root mean square error, 11.07; mean squared error, 122.61; Pearson, 0.86; mean absolute error, 7.43; Spearman, 0.87). Moreover, data interpretability was achieved by deploying the most current and robust feature importance approaches. A simple web-based application was constructed, allowing easy access by nonexpert researchers.

Conclusions

The performance of SYNPRED rivals that of the existing methods that tackle the same problem, yielding unbiased results trained with one of the most comprehensive datasets available (NCI ALMANAC). The leveraging of different reference models allowed deeper insights into which of them can be more appropriately used for synergy prediction. The Combination Sensitivity Score clearly stood out with improved performance among the full scope of surveyed approaches and synergy reference models. Furthermore, SYNPRED takes a particular focus on data interpretability, which has been in the spotlight lately when using the most advanced AI techniques.

Differential Expression of E2F Transcription Factors and Their Functional and Prognostic Roles in Human Prostate Cancer

Given the tumor heterogeneity, most of the current prognostic indicators cannot accurately evaluate the prognosis of patients with prostate cancer, and thus, the best opportunity to intervene in the progression of this disease is missed. E2F transcription factors (E2Fs) have been reported to be involved in the growth of various cancers. Accumulating studies indicate that prostate cancer (PCa) carcinogenesis is attributed to aberrant E2F expression or E2F alteration. However, the expression patterns and prognostic value of the eight E2Fs in prostate cancer have yet to be explored. In this study, The Cancer Genome Atlas (TCGA), Kaplan–Meier Plotter, Metascape, the Kyoto Encyclopedia of Genes and Genomes (KEGG), CIBERSORT, and cBioPortal and bioinformatic analysis were used to investigate E2Fs in patients with PCa. Our results showed that the expression of E2F1–3, E2F5, and E2F6 was higher in prostate cancer tissues than in benign tissues. Furthermore, elevated E2F1–3 and E2F5 expression levels were associated with a higher Gleason score (GS), advanced tumor stage, and metastasis. Survival analysis suggested that high transcription levels of E2F1–3, E2F5, E2F6, and E2F8 were associated with a higher risk of biochemical recurrence. In addition, we developed a prognostic model combining E2F1, E2F6, Gleason score, and the clinical stage that may accurately predict a biochemical recurrence-free survival. Functional enrichment analysis revealed that the E2F family members and their neighboring genes were mainly enriched in cell cycle-related pathways. Somatic mutations in different subgroups were also investigated, and immune components were predicted. Further experiments are warranted to clarify the biological associations between Pca-related E2F family genes, which may influence prognosis via the cell cycle pathway.

Anti-Androgen Receptor Therapies in Prostate Cancer: A Brief Update and Perspective

Prostate cancer is a major health issue in western countries and is the second leading cause of cancer death in American men. Prostate cancer depends on the androgen receptor (AR), a transcriptional factor critical for prostate cancer growth and progression. Castration by surgery or medical treatment reduces androgen levels, resulting in prostatic atrophy and prostate cancer regression. Thus, metastatic prostate cancers are initially managed with androgen deprivation therapy. Unfortunately, prostate cancers rapidly relapse after castration therapy and progress to a disease stage called castration-resistant prostate cancer (CRPC). Currently, clinical treatment for CRPCs is focused on suppressing AR activity with antagonists like Enzalutamide or by reducing androgen production with Abiraterone. In clinical practice, these treatments fail to yield a curative benefit in CRPC patients in part due to AR gene mutations or splicing variations, resulting in AR reactivation. It is conceivable that eliminating the AR protein in prostate cancer cells is a promising solution to provide a potential curative outcome. Multiple strategies have emerged, and several potent agents that reduce AR protein levels were reported to eliminate xenograft tumor growth in preclinical models via distinct mechanisms, including proteasome-mediated degradation, heat-shock protein inhibition, AR splicing suppression, blockage of AR nuclear localization, AR N-terminal suppression. A few small chemical compounds are undergoing clinical trials combined with existing AR antagonists. AR protein elimination by enhanced protein or mRNA degradation is a realistic solution for avoiding AR reactivation during androgen deprivation therapy in prostate cancers.

Effects of Psychological Intervention on Perioperative Quality of Life and Serum PSA and FPSA Levels of Patients with Prostate Cancer Treated with Integrated Traditional Chinese and Western Medicine

Objective

To observe the effects of psychological intervention on the perioperative quality of life and serum prostate-specific antigen (PSA) and free PSA (FPSA) levels in patients with prostate cancer treated with integrated traditional Chinese and Western medicine.

Method

A total of 208 prostate cancer patients were selected and randomly divided into a study group with 104 cases and a control group with 104 cases. The control group received a plan of basic nursing combined with integrated traditional Chinese and Western medicine, and the study group received psychological intervention on the basis of the control group. Negative emotion, pain degree, quality of life, maximum urine flow rate, residual urine volume, International Prostate Symptom Score (IPSS), and incidence of adverse reactions were compared between the two groups before and after the treatment. The levels of PSA and FPSA and the long-term efficacy of the two groups of patients before and after treatment were compared.

Results

After nursing, Hamilton Anxiety Scale (HAMA) score, Hamilton Depression Scale (HAMD) score, pain degree, maximum urine flow rate, residual urine volume, IPSS score, emotional function, social function, role function, and physical function scores of patients in two groups were decreased, and the decrease was more significant in the study group. After treatment, serum PSA and FPSA levels in the study group were obviously lower than those in the control group. The two-year cumulative survival rate of the study group was higher than that of the control group. There was no significant difference in the cognitive function score and incidence of adverse reactions between the two groups.

Conclusion

Psychological intervention combined with traditional Chinese and Western medicine in the treatment of prostate cancer can effectively improve the patient's psychological state, reduce the degree of pain in patients, improve the therapeutic effect and the quality of life of patients, and significantly reduce serum PSA and FPSA levels, which could lead to a prolonged life.

Docetaxel and prednisone with or without enzalutamide as first-line treatment in patients with metastatic castration-resistant prostate cancer: CHEIRON, a randomised phase II trial

BACKGROUND

Pre-clinical data suggest that docetaxel and enzalutamide interfere with androgen receptor translocation and signalling. The aim of this study is to assess the efficacy of their concurrent administration in the first-line treatment for metastatic castration-resistant prostate cancer (mCRPC).

METHODS

In this open-label, randomised, phase II trial, previously untreated mCRPC patients were randomised 1:1 to receive eight 21-d courses of docetaxel 75 mg/m², oral prednisone 5 mg twice daily and oral enzalutamide 160 mg/d (arm DE), or the same treatment without enzalutamide (arm D). The primary end-point was the percentage of patients without investigator-assessed disease progression 6 months after the first docetaxel administration.

RESULTS

The 246 eligible patients were randomly assigned to receive docetaxel, prednisone and enzalutamide (n = 120) or docetaxel and prednisone (n = 126). The 6-month progression rate was 12.5% (95% confidence interval [CI] 8.1-20.6) in arm DE and 27.8% (95% CI 22.8-39.4) in arm D (chi-squared test 10.01; P = 0.002). The most frequent grade III-IV adverse events were fatigue (12.5% in arm DE versus 5.6% in arm D), febrile neutropenia (9.3% versus 4.0%) and neutropenia (7.6% versus 5.6%).

CONCLUSIONS

The combination of enzalutamide and docetaxel appears to be more clinically beneficial than docetaxel alone in previously untreated mCRPC patients, although serious adverse events were more frequent. Our findings suggest that first-line treatment with this combination could lead to an additional clinical benefit when prompt and prolonged disease control is simultaneously required. Clearly, these results should be considered cautiously because of the study's phase II design and the absence of an overall survival benefit.

TRIAL REGISTRATION NUMBERS

EudraCT 2014-000175-43 - NCT02453009.

Dual-Functional PLGA Nanoparticles Co-Loaded with Indocyanine Green and Resiquimod for Prostate Cancer Treatment

PURPOSE

With the advance of screening techniques, there is a growing number of low-risk or intermediate-risk prostate cancer (PCa) cases, remaining a serious threat to men's health. To obtain better efficacy, a growing interest has been attracted to develop such emerging treatments as immunotherapy and focal therapy. However, few studies offer guidance on whether and how to combine these modalities against PCa. This study was designed to develop dual-functional nanoparticles (NPs) which combined photothermal therapy (PTT) with immunotherapy and determine the anti-tumor efficacy for PCa treatment.

METHODS

By a double emulsion technique, the drug nanocarrier, poly(lactic-co-glycolic acid) or PLGA, was applied for co-loading of a fluorescent dye, indocyanine green (ICG) and a toll-like receptor 7/8 (TLR7/8) agonist resiquimod (R848) to synthesize PLGA-ICG-R848 NPs. Next, we determined their characteristic features and evaluated whether they inhibited the cell viability in multiple PCa cell lines. After treatment with PLGA-ICG-R848, the maturation markers of bone marrow-derived dendritic cells (BMDCs) were detected by flow cytometry. By establishing a subcutaneous xenograft model of mouse PCa, we explored both the anti-tumor effect and immune response following the NPs-based laser ablation.

RESULTS

With a mean diameter of 157.7 nm, PLGA-ICG-R848 exhibited no cytotoxic effect in PCa cells, but they significantly decreased RM9 cell viability to (3.9±1.0)% after laser irradiation. Moreover, PLGA-ICG-R848 promoted BMDCs maturation with the significantly elevated proportions of CD11c+CD86+ and CD11c+CD80+ cells. Following PLGA-ICG-R848-based laser ablation in vivo, the decreased bioluminescent signals indicated a significant inhibition of PCa growth, while the ratio of splenic natural killer (NK) cells in PLGA-ICG-R848 was (3.96±1.88)% compared with (0.99±0.10)% in PBS group, revealing the enhanced immune response against PCa.

CONCLUSION

The dual-functional PLGA-ICG-R848 NPs under laser irradiation exhibit the anti-tumor efficacy for PCa treatment by combining PTT with immunotherapy.

Mechanisms of Taxane Resistance

The taxane family of chemotherapy drugs has been used to treat a variety of mostly epithelial-derived tumors and remain the first-line treatment for some cancers. Despite the improved survival time and reduction of tumor size observed in some patients, many have no response to the drugs or develop resistance over time. Taxane resistance is multi-faceted and involves multiple pathways in proliferation, apoptosis, metabolism, and the transport of foreign substances. In this review, we dive deeper into hypothesized resistance mechanisms from research during the last decade, with a focus on the cancer types that use taxanes as first-line treatment but frequently develop resistance to them. Furthermore, we will discuss current clinical inhibitors and those yet to be approved that target key pathways or proteins and aim to reverse resistance in combination with taxanes or individually. Lastly, we will highlight taxane response biomarkers, specific genes with monitored expression and correlated with response to taxanes, mentioning those currently being used and those that should be adopted. The future directions of taxanes involve more personalized approaches to treatment by tailoring drug-inhibitor combinations or alternatives depending on levels of resistance biomarkers. We hope that this review will identify gaps in knowledge surrounding taxane resistance that future research or clinical trials can overcome.

Prostate cancer: molecular and cellular mechanisms and their implications in therapy resistance and disease progression

Prostate cancer is among the most common malignancies in Western countries, and its incidence is rapidly rising in Asia where it was traditionally considered an uncommon tumor. Our understanding of the disease and management strategies continue to evolve. The first revolution of its treatment was in the 1940s when hormonal therapy was used to treat patients. The discovery of prostate-specific antigen (PSA) and the subsequent adoption of widespread PSA screening have made it possible to diagnose the disease early, but it was not until recently that the field realized that we had been overdiagnosing and overtreating a large number of men with indolent diseases that will not impact their quality of life or life expectancy. Distinguishing indolent tumors from aggressive ones remains a challenge, although recent advances in multiparametric MRI have given clinicians more confidence in choosing men for active surveillance. However, more need to be done to fundamentally understand the molecular and cellular bases that determine the biologic behavior of each of the tumors.

Second-Generation Androgen Receptor Antagonists as Hormonal Therapeutics for Three Forms of Prostate Cancer

Enzalutamide is the first second-generation nonsteroidal androgen receptor (AR) antagonist with a strong binding affinity to AR. Most significantly, enzalutamide can prolong not only overall survival time and metastatic free survival time for patients with lethal castration-resistant prostate cancer (CRPC), but also castration-resistant free survival time for patients with castration-sensitive prostate cancer (CSPC). Enzalutamide has thus been approved by the US Food and Drug Administration (FDA) for the treatment of both metastatic (in 2012) and non-metastatic (in 2018) CRPC, as well as CSPC (2019). This is an inspiring drug discovery story created by an amazing interdisciplinary collaboration. Equally important, the successful clinical use of enzalutamide proves the notion that the second-generation AR antagonists can serve as hormonal therapeutics for three forms of advanced prostate cancer. This has been further verified by the recent FDA approval of the other two second-generation AR antagonists, apalutamide and darolutamide, for the treatment of prostate cancer. This review focuses on the rational design and discovery of these three second-generation AR antagonists, and then highlights their syntheses, clinical studies, and use. Strategies to overcome the resistance to the second-generation AR antagonists are also reviewed.

Pharmacogenomic Biomarkers in Docetaxel Treatment of Prostate Cancer: From Discovery to Implementation

Prostate cancer is the fifth leading cause of male cancer death worldwide. Although docetaxel chemotherapy has been used for more than fifteen years to treat metastatic castration resistant prostate cancer, the high inter-individual variability of treatment efficacy and toxicity is still not well understood. Since prostate cancer has a high heritability, inherited biomarkers of the genomic signature may be appropriate tools to guide treatment. In this review, we provide an extensive overview and discuss the current state of the art of pharmacogenomic biomarkers modulating docetaxel treatment of prostate cancer. This includes (1) research studies with a focus on germline genomic biomarkers, (2) clinical trials including a range of genetic signatures, and (3) their implementation in treatment guidelines. Based on this work, we suggest that one of the most promising approaches to improve clinical predictive capacity of pharmacogenomic biomarkers in docetaxel treatment of prostate cancer is the use of compound, multigene pharmacogenomic panels defined by specific clinical outcome measures. In conclusion, we discuss the challenges of integrating prostate cancer pharmacogenomic biomarkers into the clinic and the strategies that can be employed to allow a more comprehensive, evidence-based approach to facilitate their clinical integration. Expanding the integration of pharmacogenetic markers in prostate cancer treatment procedures will enhance precision medicine and ultimately improve patient outcomes.