A review on the interactions between the tumor microenvironment and androgen receptor signaling in prostate cancer

Relationship between circulating miRNA-222-3p and miRNA-136-5p and the efficacy of docetaxel chemotherapy in metastatic castration-resistant prostate cancer patients

BACKGROUND

Metastatic castration-resistant prostate cancer is the most dangerous stage of prostate cancer, with a high mortality rate. Docetaxel chemotherapy is one of the most effective treatment methods currently, but some patients do not respond to chemotherapy. To avoid unnecessary toxicity in non-responders, this study explores the potential of circulating microRNAs as early biomarkers of docetaxel response in patients with metastatic castration-resistant prostate cancer.

METHODS

PC3 cells and DU145 cells were divided into the control, NC mimics, and miRNA-136-5p-mimics groups. Cell viability was measured using the CCK-8 assay. Cell apoptosis was determined by flow cytometry. Cell migration and invasion abilities were evaluated using the Transwell assay. Real-time quantitative PCR was used to measure the miRNA levels in cells and peripheral blood of patients. The miRNA-136-5p target genes were predicted by using the PITA, TargetScan, and miRanda databases. The target genes were analyzed with KEGG pathway analysis.

RESULTS

In both PC3 and DU145 cells, the miRNA-136-5p-mimics group exhibited significantly increased cell survival rates, migration and invasion numbers, and significantly decreased apoptosis rates than the control group (p < 0.05). The miRNA-222-3p and miRNA-136-5p levels were significantly increased in docetaxel-resistant PC3 and DU145 cells (p < 0.05). The levels of circulating miRNA-222-3p and miRNA-136-5p were significantly associated with docetaxel treatment (p < 0.05). Higher levels of miRNA-222-3p were observed in non-responsive patients (p < 0.05). The area under the curve for miRNA-222-3p was 0.76 (95%CI: 0.55-0.97), indicating its effectiveness as a predictive factor for non-responsive patients to docetaxel. Patients with high expression of miRNA-34c-5p after docetaxel chemotherapy had shorter overall survival times (P < 0.05). Bioinformatics analysis identified 110 potential target genes of miRNA-136-5p. KEGG revealed that these genes were mainly distributed in three pathways. Among them, the PI3K-AKT pathway was closely related to the metastasis of prostate cancer cells.

CONCLUSION

Our study demonstrates that miRNA-136-5p promotes the proliferation and invasion of PC3 and DU145 cells while inhibiting apoptosis. Circulating miRNA-222-3p may serve as a biomarker for early therapeutic response to docetaxel, and further clinical investigation is warranted. Additionally, miRNA-136-5p may have anti-cancer effects during docetaxel chemotherapy in metastatic castration-resistant prostate cancer.

ELAVL1 regulates PD-L1 mRNA stability to disrupt the infiltration of CD4-positive T cells in prostate cancer

Prostate cancer (PCa) currently ranks second in male tumor mortality. Targeting immune checkpoint in tumor as immunotherapy is a new direction for tumor treatment. However, targeting PD-1/PD-L1 and CTLA4 to treat PCa has poor immunotherapeutic efficacy because PCa is known as a cold tumor. Understanding the mechanism of immunosuppression in PCa can promote the use of immunotherapy to treat PCa. ELAVL1 is highly expressed in many tumors, participates in almost all tumor biological activities and is an oncogene. ELAVL1 is also involved in the development and differentiation of T and B lymphocytes. However, the relationship between ELAVL1 and tumor immunity has not yet been reported. In recent years, ELAVL1 has been shown to regulate downstream targets in an m6A -dependent manner. PD-L1 has been shown to have m6A sites in multiple tumors that are regulated by m6A. In this study, ELAVL1 was highly expressed in PCa, and PCa with high ELAVL1 expression is immunosuppressive. Knocking down ELAVL1 reduced PD-L1 expression in PCa. Moreover, PD-L1 was shown to have an m6A site, and its m6A level was upregulated in PCa. ELAVL1 interacts with PD-L1 mRNA and promotes PD-L1 RNA stability via m6A, ultimately inhibiting the infiltration of CD4-positive T cells. In addition, androgen receptor (AR) was shown to be regulated with ELAVL1, and knocking down AR could also affect the expression of PD-L1. Therefore, ELAVL1 can directly or indirectly regulate the expression of PD-L1, thereby affecting the infiltration of CD4-positive T cells in PCa and ultimately leading to immune suppression.

The role of NOP58 in prostate cancer progression through SUMOylation regulation and drug response

Background

Prostate cancer is one of the leading causes of cancer-related deaths in men. Its molecular pathogenesis is closely linked to various genetic and epigenetic alterations, including posttranslational modifications like SUMOylation. Identifying biomarkers that predict outcomes and specific therapeutic targets depends on a comprehensive understanding of these processes. With growing interest in SUMOylation as a mechanism affecting prostate cancer-related genes, this study aimed to investigate the central role of SUMOylation in prostate cancer prognostics, focusing on the significance of NOP58.

Methods

We conducted a comprehensive bioinformatics analysis, integrating differential expression analysis, survival analysis, gene set enrichment analysis (GSEA), and single-cell transcriptomic analyses using data from The Cancer Genome Atlas (TCGA). Key genes were identified through intersections of Venn diagrams, Boralta algorithm signatures, and machine learning models. These signaling mechanisms were validated through experimental studies, including immunohistochemical staining and gene ontology analyses.

Results

The dual-gene molecular subtype analysis with SUMO1, SUMO2, and XPO1 genes revealed significant differences in survival outcomes across molecular subtypes, further emphasizing the potential impact of NOP58 on SUMOylation, a key post-translational modification, in prostate cancer. NOP58 overexpression was strongly associated with shorter overall survival (OS), progression-free interval (PFI), and disease-specific death in prostate cancer patients. Immunohistochemical analysis confirmed that NOP58 was significantly overexpressed in prostate cancer tissues compared to normal tissues. ROC curve analysis demonstrated that NOP58 could distinguish prostate cancer from control samples with high diagnostic accuracy. Gene Ontology analysis, along with GSVA and GSEA, suggested that NOP58 may be involved in cell cycle regulation and DNA repair pathways. Moreover, NOP58 knockdown led to increased BCL2 expression and decreased Ki67 levels, promoting apoptosis and inhibiting cell proliferation. Colony formation assays further showed that NOP58 knockdown inhibited, while its overexpression promoted, colony formation, highlighting the critical role of NOP58 in prostate cancer cell growth and survival. Additionally, NOP58 was linked to drug responses, including Methotrexate, Rapamycin, Sorafenib, and Vorinostat.

Conclusion

NOP58 is a key regulator of prostate cancer progression through its mediation of the SUMOylation pathway. Its expression level serves as a reliable prognostic biomarker and an actionable therapeutic target, advancing precision medicine for prostate cancer. Targeting NOP58 may enhance therapeutic efficacy and improve outcomes in oncology.

Identifying multi-target drugs for prostate cancer using machine learning-assisted transcriptomic analysis

Prostate cancer is a leading cause of cancer death in men, and the development of effective treatments is of great importance. This study explored to identify the candidate drugs for prostate cancer by transcriptomic data and CMap database analysis. After integrating the results of omics analysis, bisoprolol is confirmed as a promising drug. Moreover, cell experiment reveals its potential inhibitory effect on the proliferation of prostate cancer cells. Importantly, machine learning methods are employed to predict the targets of bisoprolol, and the dual-target ADRB3 and hERG are explored by dynamic simulation. The findings of this study demonstrate the potential of bisoprolol as a multi-target drug for prostate cancer treatment and the feasibility of using beta-adrenergic receptor inhibitors in prostate cancer treatment. In addition, the proposed research approach is promising for discovering potential drugs for cancer treatment by leveraging the concept of drug side effects leading to anticancer effects. Further research is necessary to investigate the pharmacological action, potential toxicity, and underlying mechanisms of bisoprolol in treating prostate cancer with ADRB3.Communicated by Ramaswamy H. Sarma.

Therapeutic potential of targeting mirnas to prostate cancer tumors: using psma as an active target

Prostate cancer (PC) is a commonly diagnosed malignancy in men and is associated with high mortality rates. Current treatments for PC include surgery, chemotherapy, and radiation therapy. However, recent advances in targeted delivery systems have yielded promising new approaches to PC treatment. As PC epithelial cells express high levels of prostate-specific membrane antigen (PSMA) on the cell surface, new drug conjugates focused on PSMA targeting have been developed. microRNAs (miRNAs) are small noncoding RNAs that regulate posttranscriptional gene expression in cells and show excellent possibilities for use in developing new therapeutics for PC. PSMA-targeted therapies based on a miRNA payload and that selectively target PC cells enhances therapeutic efficacy without eliciting damage to normal surrounding tissue. This review discusses the rationale for utilizing miRNAs to target PSMA, revealing their potential in therapeutic approaches to PC treatment. Different delivery systems for miRNAs and challenges to miRNA therapy are also explored.

The involvement of high succinylation modification in the development of prostate cancer

OBJECTIVE

Succinylation modification of the lysine site plays an important role in tumorigenesis and development, but it is rarely reported in prostate cancer (PCa), so this study aims to elucidate its expression in and clinical correlation with PCa.

METHODS

A total of 95 tumor, 3 normal and 52 paired adjacent tissue of PCa were involved for succinylation stanning. 498 PCa samples with 20 succinylation modification-related genes from TCGA were downloaded for model construction. Statistical methods were employed to analyze the data, including Non-Negative Matrix Factorization (NMF) algorithm, t-Distributed Stochastic Neighbor Embedding (t-SNE) algorithm and Cox regression analysis.

RESULTS

The pan-succinyllysine antibody stanning indicated that tumor tissues showed higher succinyllysine level than adjacent tissues (p<0.001). Gleason grade and PDL1 expression levels were significantly different (p<0.001) among the high, medium and low succinylation staining scores. The types of PCa tissue were divided into four clusters using RNA-seq data of 20 succinylation-related genes in TCGA database. Clinical characterize of age, PSA level, and pathological stage showed differences among four clusters. The expression of succinylation-related genes (KAT5, SDHD and GLYATL1) and PCa related genes (PDL1, AR and TP53) were significantly different in 52 matched tumor and adjacent tissues (p<0.001). GLYATL1 and AR gene expression was significantly related to the pathological stage of PCa.

CONCLUSION

Succinylation was significantly increased in PCa tissues and was closely related to Gleason grade and PD-L1 expression. Model construction of 20 genes related to succinylation modification showed that the later the pathological stage of PCa, the higher the level of succinylation modification.

α-Terthienyl induces prostate cancer cell death through inhibiting androgen receptor expression

Prostate cancer is a disease that often occurs in elderly men. Androgen receptor signaling pathway runs through the occurrence and development of prostate cancer. Thereby, targeting androgen receptor is a crucial strategy for the treatment of prostate cancer. α-Terthienyl, which has been used as photosensitive activator and insecticide, is a natural compound rich in marigold. In the present study, we found α- terthienyl could inhibit the cell viability of four prostate cancer cell lines, especially on LNCaP and 22Rv1 cells which endogenously express androgen receptor. Then we proved that it could inhibit the proliferation of prostate cancer cells and induce apoptosis of prostate cancer cells by plate clone formation assay and flow cytometry respectively. Furthermore, we found α-terthienyl could inhibit androgen receptor nuclear translocation, reduce androgen receptor expression, reduce the mRNA and protein expression of androgen receptor target genes (KLK3, TMPRSS2, PCA3) and nuclear proliferation antigen Ki67 and PCNA. In addition, it inhibited the expression and phosphorylation of Akt protein while increasing the expression of tumor suppressor p27. Besides, we constructed a mouse xenograft prostate cancer model and confirmed that α-terthienyl also inhibited the growth of prostate cancer in vivo. In conclusively, α-terthienyl played an anti-prostate cancer role by inhibiting both the expression of androgen receptor and the transduction of its signal pathway, suggesting that it is a promising natural small molecule for the treatment of prostate cancer.

Phloretin in Benign Prostate Hyperplasia and Prostate Cancer: A Contemporary Systematic Review

Currently, medication for benign prostate hyperplasia (BPH) and prostate cancer (PCa) are mainly based on modulating the hormone and nervous systems. However, side effects often affect patients, and might decrease their commitment to continuing the medication and lower their quality of life. Some studies have indicated that chronic inflammation might be the cause of BPH and PCa. Based on this hypothesis, the effect of phloretin, a potent anti-inflammatory and anti-oxidative flavonoid, has been researched since 2010. Results from animal and in-vitro studies, obtained from databases, also indicate that the use of phloretin in treating BPH and PCa is promising. Due to its effect on inflammatory cytokines, apoptosis or anti-apoptosis, reactive oxygen species, anti-oxidant enzymes and oxidative stress, phloretin is worthy of further study in human clinical trials regarding safety and effective dosages.

PD-L1 Up-Regulation in Prostate Cancer Cells by Porphyromonas gingivalis

Chronic inflammation is known to contribute to various human cancers. Porphyromonas gingivalis (P. gingivalis), is a gram-negative oral keystone pathogen that may cause severe periodontitis and expresses several virulence factors to affect the host immune system. Periodontitis is a chronic infectious disease that while progression, may cause loss of attachment and destruction of the tooth supporting tissues. Prostate cancer is one of the most common malignancies in men. Increasing evidence links periodontitis with prostate cancer, however the mechanisms explaining this relationship remain unclear. The aim of this study was to investigate the expression and signaling pathway of programmed death ligand 1 (PD-L1) in a prostate cancer cell line after infection with P. gingivalis and stimulation with P. gingivalis components to reveal the mechanism of tumor-induced immune evasion associated with bacterial infection in the tumor environment. Prostate cancer cells were infected with different concentrations of viable P. gingivalis and treated with different concentrations of heat-killed P. gingivalis and P. gingivalis cell components, including the total membrane fraction, inner membrane fraction, outer membrane fraction, cytosolic fraction and peptidoglycan (PGN). Chemical inhibitors were used to block different important molecules of signaling pathways to assess the participating signal transduction mechanisms. PD-L1 expression was detected by Western blot after 24 h of infection. PD-L1 was demonstrated to be upregulated in prostate cancer cells after infection with viable and with heat-killed P. gingivalis membrane fractions. Also isolated PGN induced PD-L1 up-regulation. The upregulation was mediated by the NOD1/NOD2 signaling pathway. No upregulation could be detected after treatment of the cells with P. gingivalis lipopolysaccharide (LPS). These results indicate, that chronic inflammatory disease can contribute to tumor immune evasion by modifying the tumor microenvironment. Thus, chronic infection possibly plays an essential role in the immune response and may promote the development and progression of prostate cancer.

Better Understanding the Timing of Androgen Deprivation (TOAD) Trial Outcomes: Impacts of Prior ADT

Background

The Timing Of Androgen Deprivation (TOAD) trial found an overall survival benefit for immediate vs delayed androgen deprivation therapy (ADT) for prostate-specific antigen (PSA)–relapsed or noncurable prostate cancer. However, broad eligibility criteria allowed entry of a heterogeneous participant group, including those with prior ADT exposure, raising concerns about subsequent androgen sensitivity. For these reasons, we completed previously specified subgroup analyses to assess if prior ADT was associated with ADT timing efficacy after PSA relapse.

Methods

We examined TOAD trial patient-level data for participants with PSA relapse after local therapy. We performed Kaplan-Meier analyses for overall survival stratified by prior ADT and randomized treatment arm (immediate or delayed ADT). We compared group characteristics using Mann-Whitney U and Fisher exact tests. All hypothesis tests were 2-sided.

Results

We identified 261 patients with PSA relapse, 125 of whom received prior ADT. Patients with prior ADT had higher PSA at presentation (12.1 vs 9.0 ng/mL; P < .001), more cT3 disease (38.4% vs 25.0%; P = .007), and more likely received radiotherapy as local treatment (80.0% vs 47.8%; P < .001) but were otherwise similar to patients without prior ADT exposure. Within this prior ADT group, those who received immediate ADT (n = 56) had improved overall survival compared with those who received delayed ADT (n = 69; P = .02). This benefit was not observed in the group with no prior ADT (P = .98).

Conclusions

The survival benefit demonstrated in the TOAD trial may be driven by patients who received ADT prior to trial entry. We provide possible explanations for this finding with implications for treatment of PSA-relapsed prostate cancer and future study planning.

Identifying prognostic signatures in the microenvironment of prostate cancer

Background

An increasing number of studies has indicated that the tumor microenvironment (TME), an important component of tumor tissue, has clinicopathological significance in predicting disease outcome and therapeutic efficacy. However, little evidence in prostate cancer (PCa) is available.

Methods

The cohort of TCGA-PRAD (n=477) was used in this study. Based on the proportion of 22 types of immune cells calculated by CIBERSORT, the TME was classified by K-means clustering and differentially expressed genes (DEGs) were determined. The TMEscore was calculated based on cluster signature genes, which were obtained from DEGs by the random forest method, and the samples were classified into two subtypes. Analyses of somatic mutation and copy number variation (CNVs) were further conducted to identify the genetic characteristics of the two subtypes. Correlation analysis was performed to explore the correlation between TMEscore and the tumor response to immune checkpoint inhibitors (ICIs) as well as the prognosis of PCa.

Results

Based on the distribution of infiltrating immune cells in the TME, we constructed the TMEscore model and classified PCa samples into high and low TMEscore groups. Survival analysis indicated that the high TMEscore group had significantly better survival outcome than the low TMEscore group. Correlation analysis showed a significantly positive correlation between TMEscore and the known prognostic factors of PCa.

Conclusions

Our study indicates that the TMEscore could be a potential prognostic biomarker in PCa. A comprehensive description of the characteristics of TME may help predict the response to therapies and provide new treatment strategies for PCa patients.

Prostate Microbiota and Prostate Cancer: A New Trend in Treatment

Although the incidence and mortality of prostate cancer have gradually begun to decline in the past few years, it is still one of the leading causes of death from malignant tumors in the world. The occurrence and development of prostate cancer are affected by race, family history, microenvironment, and other factors. In recent decades, more and more studies have confirmed that prostate microflora in the tumor microenvironment may play an important role in the occurrence, development, and prognosis of prostate cancer. Microorganisms or their metabolites may affect the occurrence and metastasis of cancer cells or regulate anti-cancer immune surveillance. In addition, the use of tumor microenvironment bacteria in interventional targeting therapy of tumors also shows a unique advantage. In this review, we introduce the pathway of microbiota into prostate cancer, focusing on the mechanism of microorganisms in tumorigenesis and development, as well as the prospect and significance of microorganisms as tumor biomarkers and tumor prevention and treatment.

Prostate Cancer Immunotherapy-Finally in From the Cold?

PURPOSE OF REVIEW

Despite significant progress, patients with metastatic prostate cancer continue to have poor prognosis. Immunotherapy has revolutionized cancer care for many tumor types but has a limited role in the treatment of prostate cancer. This review discusses the promise of immunotherapy in prostate cancer treatment with an emphasis on emerging therapeutic targets.

RECENT FINDINGS

Most prostate tumors have low tumor mutational burden and lack immunogenicity, representing significant hurdles to induction of anti-tumor immunity. However, recent research centered on deciphering key mechanisms of immune resistance in the prostate tumor microenvironment has led to the discovery of a range of new treatment targets. These discoveries are currently being translated into innovative immunotherapy clinical trials for patients with prostate cancer. Recent progress includes early evidence of activity for these novel approaches and the identification of potential predictive biomarkers of response. Novel treatment strategies using new antigen-directed therapies, drugs targeting the immunosuppressive tumor microenvironment, and combination immunotherapy therapies show great potential and are currently in clinical development. In addition, a deeper understanding of predictors of response and resistance to immunotherapy in prostate cancer is allowing for a more personalized approach to therapy.

Current Status and Future Perspectives of Androgen Receptor Inhibition Therapy for Prostate Cancer: A Comprehensive Review

The androgen receptor (AR) is one of the main components in the development and progression of prostate cancer (PCa), and treatment strategies are mostly directed toward manipulation of the AR pathway. In the metastatic setting, androgen deprivation therapy (ADT) is the foundation of treatment in patients with hormone-sensitive prostate cancer (HSPC). However, treatment response is short-lived, and the majority of patients ultimately progress to castration-resistant prostate cancer (CRPC). Surmountable data from clinical trials have shown that the maintenance of AR signaling in the castration environment is accountable for disease progression. Study results indicate multiple factors and survival pathways involved in PCa. Based on these findings, the alternative molecular pathways involved in PCa progression can be manipulated to improve current regimens and develop novel treatment modalities in the management of CRPC. In this review, the interaction between AR signaling and other molecular pathways involved in tumor pathogenesis and its clinical implications in metastasis and advanced disease will be discussed, along with a thorough overview of current and ongoing novel treatments for AR signaling inhibition.

The Impact of Neoadjuvant Hormone Therapy on Surgical and Oncological Outcomes for Patients With Prostate Cancer Before Radical Prostatectomy: A Systematic Review and Meta-Analysis

Objective

This systematic study aimed to assess and compare the comprehensive evidence regarding the impact of neoadjuvant hormone therapy (NHT) on surgical and oncological outcomes of patients with prostate cancer (PCa) before radical prostatectomy (RP).

Methods

Literature searches were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Using PubMed, Web of Science, Chinese National Knowledge Infrastructure, and Wanfang databases, we identified relevant studies published before July 2020. The pooled effect sizes were calculated in terms of the odds ratios (ORs)/standard mean differences (SMDs) with 95% confidence intervals (CIs) using the fixed or random-effects model.

Results

We identified 22 clinical trials (6 randomized and 16 cohort) including 20,199 patients with PCa. Our meta-analysis showed no significant differences in body mass index (SMD = 0.10, 95% CI: -0.08-0.29, p = 0.274) and biopsy Gleason score (GS) (OR = 1.33, 95% CI: 0.76-2.35 p = 0.321) between the two groups. However, the NHT group had a higher mean age (SMD = 0.19, 95% CI: 0.07-0.31, p = 0.001), preoperative prostate-specific antigen (OR = 0.47, 95% CI: 0.19-0.75, p = 0.001), and clinic tumor stage (OR = 2.24, 95% CI: 1.53-3.29, p < 0.001). Compared to the RP group, the NHT group had lower positive surgical margins (PSMs) rate (OR = 0.44, 95% CI: 0.29-0.67, p < 0.001) and biochemical recurrence (BCR) rate (OR = 0.47, 95% CI: 0.26-0.83, p = 0.009). Between both groups, there were no significant differences in estimated blood loss (SMD = -0.06, 95% CI: -0.24-0.13, p = 0.556), operation time (SMD = 0.20, 95% CI: -0.12-0.51, p = 0.219), pathological tumor stage (OR = 0.76, 95% CI: 0.54-1.06, p = 0.104), specimen GS (OR = 0.91, 95% CI: 0.49-1.68, p = 0.756), and lymph node involvement (OR = 0.76, 95% CI: 0.40-1.45, p = 0.404).

Conclusions

NHT prior to RP appeared to reduce the tumor stage, PSMs rate, and risk of BCR in patients with PCa. According to our data, NHT may be more suitable for older patients with higher tumor stage. Besides, NHT may not increase the surgical difficulty of RP.

Androgen Receptor Signaling Pathway in Prostate Cancer: From Genetics to Clinical Applications

Around 80-90% of prostate cancer (PCa) cases are dependent on androgens at initial diagnosis; hence, androgen ablation therapy directed toward a reduction in serum androgens and the inhibition of androgen receptor (AR) is generally the first therapy adopted. However, the patient's response to androgen ablation therapy is variable, and 20-30% of PCa cases become castration resistant (CRPCa). Several mechanisms can guide treatment resistance to anti-AR molecules. In this regard, AR-dependent and -independent resistance mechanisms can be distinguished within the AR pathway. In this article, we investigate the multitude of AR signaling aspects, encompassing the biological structure of AR, current AR-targeted therapies, mechanisms driving resistance to AR, and AR crosstalk with other pathways, in an attempt to provide a comprehensive review for the PCa research community. We also summarize the new anti-AR drugs approved in non-metastatic castration-resistant PCa, in the castration-sensitive setting, and combination therapies with other drugs.

The Utilization of Poly(2-ethyl-2-oxazoline)-b-Poly(ε-caprolactone) Ellipsoidal Particles for Intracellular BIKDDA Delivery to Prostate Cancer

Prostate cancer is the most common cancer, which is about 15-20% among male cancers worldwide. As most common strategies such as radiotherapy, chemotherapy, or surgery alone can be unsuccessful in the treatment of prostate cancer, this study aims to develop a new approach to deliver newly generated proapoptotic gene, BIKDDA, to androgen independent prostate cancer cells, 22RV1, using new generation nanocarriers called ellipsoids. As far as it is known, this is the first study that assesses the ability of proapoptotic gene BIKDDA to induce apoptosis in prostate cancer cell. BIKDDA encapsulating PEtOx-b-PCL-based ellipsoids are fabricated by solvent-switch method, and their morphology, size, and BIKDDA content are characterized. Gene delivery efficiency of BIKDDA loaded PEtOx-b-PCL ellipsoids is demonstrated by analysis of BIK mRNA expression with real-time PCR. The apoptotic effect of PEtOx-b-PCL ellipsoids loaded with BIKDDA (EPs-BIKDDA) on 22RV1 is shown by Annexin V staining. The obtained results demonstrate that the treatment of 22RV1 cells with EPs-BIKDDA can significantly increase BIK mRNA levels by 4.5-fold leading to cell death. This study not only represents BIKDDA as a potential therapeutic strategy in prostate cancer but also the capacity of ellipsoids as promising in vivo gene delivery vehicles.

Salivary gland cancer in the era of immunotherapy: can we exploit tumor microenvironment?

INTRODUCTION

Salivary gland cancers (SGCs) consist of a rare family of neoplasms with varying histology and biological behavior. Therapeutic regimens have been relatively unchanged for decades. The recent successes of immunotherapy have raised hopes for the development of more effective strategies in SGC, thus emphasizing the role of tumor microenvironment (TME) in the design for more effective therapies.

AREAS COVERED

This review presents an overview of the current knowledge on the pathobiology of SGC TME and discusses the potential of immunotherapeutic targeting.

EXPERT OPINION

Most data on the role of TME in SGC carcinogenesis are derived from preclinical studies. Signaling cascades of immunotherapeutic interest, PD-1/PD-L1 and PD-1/PD-L2, are active in many SGCs and might be associated with biological behavior and prognosis. Immunotherapeutic attempts are very limited, but recent findings in other tumors on the role of exosomes and PD-L2 signaling suggest that TME of SGCs warrants further research, emphasizing larger cohorts, histology-based stratification, and standardized evaluation of immunomodulatory molecules, to explore the potential of targeting tumor stroma and its signaling cascades. Furthermore, combination of immunotherapies or immunotherapies with the antineoplastic agents targeting AR, HER2, and tyrosine kinases, recently introduced in SGC treatment, constitutes a promising approach for the future.

Complexity of Neural Component of Tumor Microenvironment in Prostate Cancer

The tumor microenvironment (TME) plays an essential role in the development and progression of neoplasms. TME consists of the extracellular matrix and numerous specialized cells interacting with cancer cells by paracrine and autocrine mechanisms. Tumor axonogenesis and neoneurogenesis constitute a developing area of investigation. Prostate cancer (PC) is one of the most common malignancies in men worldwide. During the past years, more and more studies have shown that mechanisms leading to the development of PC are not confined only to the epithelial cancer cell, but also involve the tumor stroma. Different nerve types and neurotransmitters present within the TME are thought to be important factors in PC biology. Moreover, perineural invasion, which is a common way of PC spreading, in parallel creates the neural niche for malignant cells. Cancer neurobiology seems to have become a new discipline to explore the contribution of neoplastic cell interactions with the nervous system and the neural TME component, also to search for potential therapeutic targets in malignant tumors such as PC.

Alleviation of Multidrug Resistance by Flavonoid and Non-Flavonoid Compounds in Breast, Lung, Colorectal and Prostate Cancer

The aim of the manuscript is to discuss the influence of plant polyphenols in overcoming multidrug resistance in four types of solid cancers (breast, colorectal, lung and prostate cancer). Effective treatment requires the use of multiple toxic chemotherapeutic drugs with different properties and targets. However, a major cause of cancer treatment failure and metastasis is the development of multidrug resistance. Potential mechanisms of multidrug resistance include increase of drug efflux, drug inactivation, detoxification mechanisms, modification of drug target, inhibition of cell death, involvement of cancer stem cells, dysregulation of miRNAs activity, epigenetic variations, imbalance of DNA damage/repair processes, tumor heterogeneity, tumor microenvironment, epithelial to mesenchymal transition and modulation of reactive oxygen species. Taking into consideration that synthetic multidrug resistance agents have failed to demonstrate significant survival benefits in patients with different types of cancer, recent research have focused on beneficial effects of natural compounds. Several phenolic compounds (flavones, phenolcarboxylic acids, ellagitannins, stilbens, lignans, curcumin, etc.) act as chemopreventive agents due to their antioxidant capacity, inhibition of proliferation, survival, angiogenesis, and metastasis, modulation of immune and inflammatory responses or inactivation of pro-carcinogens. Moreover, preclinical and clinical studies revealed that these compounds prevent multidrug resistance in cancer by modulating different pathways. Additional research is needed regarding the role of phenolic compounds in the prevention of multidrug resistance in different types of cancer.

Network-based analysis of prostate cancer cell lines reveals novel marker gene candidates associated with radioresistance and patient relapse

Radiation therapy is an important and effective treatment option for prostate cancer, but high-risk patients are prone to relapse due to radioresistance of cancer cells. Molecular mechanisms that contribute to radioresistance are not fully understood. Novel computational strategies are needed to identify radioresistance driver genes from hundreds of gene copy number alterations. We developed a network-based approach based on lasso regression in combination with network propagation for the analysis of prostate cancer cell lines with acquired radioresistance to identify clinically relevant marker genes associated with radioresistance in prostate cancer patients. We analyzed established radioresistant cell lines of the prostate cancer cell lines DU145 and LNCaP and compared their gene copy number and expression profiles to their radiosensitive parental cells. We found that radioresistant DU145 showed much more gene copy number alterations than LNCaP and their gene expression profiles were highly cell line specific. We learned a genome-wide prostate cancer-specific gene regulatory network and quantified impacts of differentially expressed genes with directly underlying copy number alterations on known radioresistance marker genes. This revealed several potential driver candidates involved in the regulation of cancer-relevant processes. Importantly, we found that ten driver candidates from DU145 (ADAMTS9, AKR1B10, CXXC5, FST, FOXL1, GRPR, ITGA2, SOX17, STARD4, VGF) and four from LNCaP (FHL5, LYPLAL1, PAK7, TDRD6) were able to distinguish irradiated prostate cancer patients into early and late relapse groups. Moreover, in-depth in vitro validations for VGF (Neurosecretory protein VGF) showed that siRNA-mediated gene silencing increased the radiosensitivity of DU145 and LNCaP cells. Our computational approach enabled to predict novel radioresistance driver gene candidates. Additional preclinical and clinical studies are required to further validate the role of VGF and other candidate genes as potential biomarkers for the prediction of radiotherapy responses and as potential targets for radiosensitization of prostate cancer.

Prostate cancer cell lines represent an important model system to characterize molecular alterations that contribute to radioresistance, but irradiation can cause deletions and amplifications of DNA segments that affect hundreds of genes. This in combination with the small number of cell lines that are usually considered does not allow a straight-forward identification of driver genes by standard statistical methods. Therefore, we developed a network-based approach to analyze gene copy number and expression profiles of such cell lines enabling to identify potential driver genes associated with radioresistance of prostate cancer. We used lasso regression in combination with a significance test for lasso to learn a genome-wide prostate cancer-specific gene regulatory network. We used this network for network flow computations to determine impacts of gene copy number alterations on known radioresistance marker genes. Mapping to prostate cancer samples and additional filtering allowed us to identify 14 driver gene candidates that distinguished irradiated prostate cancer patients into early and late relapse groups. In-depth literature analysis and wet-lab validations suggest that our method can predict novel radioresistance driver genes. Additional preclinical and clinical studies are required to further validate these genes for the prediction of radiotherapy responses and as potential targets to radiosensitize prostate cancer.