Achieving optimal delivery of follow-up care for prostate cancer survivors: improving patient outcomes

RNA N6-methyladenosine-modified-binding protein YTHDF1 promotes prostate cancer progression by regulating androgen function-related gene TRIM68

PURPOSE

There is no report about the direct relationship between m6A modification and androgen receptor (AR)-related genes in prostate cancer (PC). We aimed to study the mechanisms of m6A methylation in regulating the pathogenesis of PC from the perspective of AR-related genes.

METHODS

qRT-PCR was applied to detect the expression of m6A-related genes in PC cell with or without AR inhibitor. The effects of YTHDF1 knockdown on PC cell viability, apoptosis, migration and invasion were investigated using flow cytometry, wound healing and transwell assays, respectively. The mechanism of YTHDF1 action was investigated using m6A RNA immunoprecipitation (MeRIP) sequencing. The biological functions of YTHDF1 were also explored through in vivo experiments.

RESULTS

YTHDF1 was significantly down-regulated in AR inhibitor group. YTHDF1 knockdown significantly decreased AR level, viability and m6A methylation level of PC cells. TRIM68 was identified as a direct target of YTHDF1. Both YTHDF1 and TRIM68 knockdown increased apoptosis, and decreased cell viability, migration, and invasion of PC cells, while TRIM68 overexpression reversed the effects of YTHDF1 knockdown on PC cells. In addition, knockdown of YTHDF1 or TRIM68 significantly decreased the m6A methylation level, and mRNA and protein levels of YTHDF1, TRIM68 and AR in PC cells, while TRIM68 overexpression increased the expression levels above. Furthermore, subcutaneous xenografts of nude mice also revealed that TRIM68 could reverse the effects of YTHDF1 knockdown in PC in vivo.

CONCLUSION

This study suggested the key role of YTHDF1-mediated m6A modification in PC progression by regulating androgen function-related gene TRIM68 in PC.

Role of main RNA modifications in cancer: N6-methyladenosine, 5-methylcytosine, and pseudouridine

Cancer is one of the major diseases threatening human life and health worldwide. Epigenetic modification refers to heritable changes in the genetic material without any changes in the nucleic acid sequence and results in heritable phenotypic changes. Epigenetic modifications regulate many biological processes, such as growth, aging, and various diseases, including cancer. With the advancement of next-generation sequencing technology, the role of RNA modifications in cancer progression has become increasingly prominent and is a hot spot in scientific research. This review studied several common RNA modifications, such as N⁶-methyladenosine, 5-methylcytosine, and pseudouridine. The deposition and roles of these modifications in coding and noncoding RNAs are summarized in detail. Based on the RNA modification background, this review summarized the expression, function, and underlying molecular mechanism of these modifications and their regulators in cancer and further discussed the role of some existing small-molecule inhibitors. More in-depth studies on RNA modification and cancer are needed to broaden the understanding of epigenetics and cancer diagnosis, treatment, and prognosis.

The FTO m6A demethylase inhibits the invasion and migration of prostate cancer cells by regulating total m6A levels

AIMS

N6-Methyladenosine (m⁶A) is the most frequent posttranscriptional modification and plays important roles in tumorigenesis and metastasis. The roles of fat mass and obesity-associated (FTO) in metabolic diseases have been widely explored. However, the molecular mechanisms and physiological functions of FTO in prostate cancer remain largely unknown. This study aimed to explore the exact functions of FTO in the progression of prostate cancer metastasis.

MAIN METHODS

Dot blot and m⁶A RNA methylation quantification assays were performed to determine m⁶A levels. The protein and mRNA expression levels were detected using immunoblot (IB) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses. Cell invasion and migration abilities were measured using transwell and wound healing assays. Bioinformatics was used to measure the expression level of FTO and possible correlation between FTO levels and advanced tumor stage. Immunofluorescence (IF) was performed to measure the cellular localization of FTO.

KEY FINDINGS

FTO was downregulated in prostate cancer tissues and cell lines, and the m⁶A content was increased. Importantly, patients with lower FTO expression had advanced tumor stage and higher Gleason scores. Gain- and loss-of-function assays revealed that FTO inhibits prostate cancer cell invasion and migration in vitro. Moreover, we confirmed that FTO can decrease the total m⁶A level.

SIGNIFICANCE

The present study revealed that the FTO m⁶A demethylase inhibits prostate cancer cell invasion and migration by regulating total m⁶A levels.

Lower Urinary Tract Symptoms in Prostate Cancer Patients Treated With Radiation Therapy: Past and Present

The incidence of prostate cancer (PCa) is increasing concomitantly with population aging. Accordingly, interest in radiation therapy (RT) and the frequency of RT are also increasing. The types of RT can be broadly divided into external beam RT (EBRT), brachytherapy (BT), and combination therapy (EBRT+BT). Lower urinary tract symptoms (LUTS) after RT for the treatment of PCa are common; however, there are few reviews on the relationship between RT and LUTS. Herein, we review the causes and incidence of LUTS, as well as the evaluation and treatment options. Because of the reported risks of RT, patients undergoing RT should be counseled regarding the challenges of treatment and informed that they may have higher failure rates than nonirradiated patients. Moreover, thorough evaluation and treatment strategies are needed to support treatment recommendations. With a review of the existing literature, this narrative article provides an overview to aid urologists in treating patients presenting with complications associated with RT for the treatment of PCa. Further research is required to provide evidence of the effectiveness and feasibility of the management approach to the care of patients with LUTS after RT for the treatment of PCa.

RNA m6A Methyltransferase METTL3 Promotes The Growth Of Prostate Cancer By Regulating Hedgehog Pathway

Purpose

N⁶-methyladenosine (m⁶A) is the most abundant internal modification on eukaryotic mRNA and gained increasing attention recently. More and more evidence suggest that m⁶A methylation plays crucial role in tumor genesis and development. However, its role in prostate cancer remains largely unknown.

Methods

METTL3 expression status in prostate cancer was analyzed by using TCGA database and Western blotting. m⁶A content was analyzed by using RNA Methylation Quantification Kit. The role of METTL3 in prostate cancer cells was determined by proliferation, survival, colony formation, and invasion assays. The m⁶A level of GLI1 RNA was detected by methylated RNA immunoprecipitation (MeRIP) assay. In vivo role of METTL3 was studied on xenograft models.

Results

We found that m⁶A methyltransferase METTL3 was overexpressed in prostate cancer cell lines, together with increased m⁶A content. Functionally, silencing of METTL3 by shRNA in prostate cancer cell lines resulted in decreased m⁶A content, cell proliferation, survival, colony formation, and invasion. Interestingly, overexpression of wild-type METTL3 abrogated the repression effect of METTL3 depletion on m⁶A content, cell proliferation, survival, colony formation, and invasion, while the overexpression of m⁶A catalytic site mutant METTL3 was unable to rescue the inhibitory effect caused by METTL3 depletion. Further mechanism analysis demonstrated that METTL3 silence decreased the m⁶A modification and expression of GLI1, an important component of hedgehog pathway, which led to cell apoptosis. Moreover, depletion of METTL3 inhibited tumor growth in vivo.

Conclusion

Our results suggested that the m⁶A methyltransferase METTL3 promotes the growth and motility of prostate cancer cells by regulating hedgehog pathway.

Development and usability testing of the e-EXCELS tool to guide cancer survivorship follow-up care

OBJECTIVE

The aim of this study is to describe a user-centered (e.g., cancer survivors and clinicians) development process of an eHealth tool designed to facilitate self-management of cancer survivorship follow-up care.

METHODS

Guided by Cognitive-Social Health Information Processing (C-SHIP) model and informed by core self-management skills, we engaged in a user-centered design process. In phase I, we conducted in-depth interviews with survivors of breast (n = 33), prostate (n = 4), and colorectal (n = 6) cancers, and (n = 9) primary care providers to develop content and design of the web tool. Phase II utilized iterative user testing interviews (n = 9) to test the web-based tool prototype. Data from both phases were independently coded using a template/content analytic approach.

RESULTS

The top 5 functions identified in phase I for the web-based platform included: (a) educational materials to learn and prepare for health encounters (80%); (b) questions for health providers (74%); (c) ability to track contact information of providers (67%); (d) provide general information (64%); and, (e) support information (62%). Users of the prototype reported patient burden, tool fatigue, introduction timing of the tool, relevance, and security/privacy as concerns in phase II.

CONCLUSIONS

This study demonstrates the value of using a theoretically informed and user-centered design process to develop relevant and patient-centered eHealth resources to support cancer survivorship. A larger study is needed to establish the efficacy of this eHealth tool as an intervention to improve adherence to follow-up care guidelines.

Eya2 Is Overexpressed in Human Prostate Cancer and Regulates Docetaxel Sensitivity and Mitochondrial Membrane Potential through AKT/Bcl-2 Signaling

The aberrant expression of Eya2 has been observed in a wide range of cancer types. However, the clinical significance and biological effects of EYA2 in human prostate cancer remain unknown. In this study, we showed that increased levels of Eya2 protein correlated with advanced TNM stage, T stage, and a higher Gleason score. Data from the Cancer Genome Atlas (TCGA) prostate cohort consistently revealed that Eya2 mRNA was positively correlated with a higher Gleason score, higher T stage, and positive nodal metastasis in prostate cancer. Furthermore, data from the Oncomine database showed increased levels of EYA2 mRNA expression in prostate cancer tissues compared with normal tissues. Eya2 protein expression was also higher in prostate cancer cell lines compared with a normal RWPE-1 cell line. We selected LNCaP and PC-3 cell lines for plasmid overexpression and shRNA knockdown. CCK-8, colony formation, and Matrigel invasion assays demonstrated that the overexpression of Eya2 promoted proliferation, colony number, and invasion while Eya2 shRNA inhibited proliferation rate, colony formation, and invasion ability. CCK-8 and Annexin V assays showed that Eya2 reduced sensitivity to docetaxel and docetaxel-induced apoptosis while Eya2 shRNA showed the opposite effects. The overexpression of Eya2 also downregulated the cleavage of caspase3 and PARP while Eya2 depletion upregulated caspase3 and PARP cleavage. Notably, JC-1 staining demonstrated that Eya2 upregulated mitochondrial membrane potential. We further revealed that the overexpression of Eya2 upregulated Bcl-2, matrix metalloproteinase 7 (MMP7), and AKT phosphorylation. Accordingly, data from the TCGA prostate cohort indicated that EYA2 mRNA was positively correlated with the expression of Bcl-2 and MMP7. The inhibition of AKT attenuated EYA2-induced Bcl-2 upregulation. In conclusion, our data demonstrated that Eya2 was upregulated in prostate cancers. EYA2 promotes cell proliferation and invasion as well as cancer progression by regulating docetaxel sensitivity and mitochondrial membrane potential, possibly via the AKT/Bcl-2 axis.

Deubiquitinase USP9X regulates the invasion of prostate cancer cells by regulating the ERK pathway and mitochondrial dynamics

The ubiquitin-specific protease 9X (USP9X) is a conserved deubiquitinase that has been investigated in several types of human cancer. However, the clinical significance and the biological roles of USP9X in prostate cancer remain unexplored. In the present study, an investigation into the expression and clinical significance of USP9X in prostate cancer revealed that USP9X expression was downregulated in prostate cancer tissues compared with that in healthy tissues. In addition, decreased USP9X expression was associated with a higher Gleason score and local invasion. Depletion of USP9X in prostate cancer LNCaP and PC-3 cells by small interfering RNA promoted cell invasion and migration. Furthermore, USP9X depletion upregulated matrix metalloproteinase 9 (MMP9) and the phosphorylation of dynamin-related protein 1 (DRP1). Notably, a significant increase in phosphorylated extracellular signal-regulated kinase (ERK), an upstream activator of MMP9 and DRP1, was observed. To investigate whether ERK activation was able to increase MMP9 protein levels and induce DRP1 phosphorylation, an ERK inhibitor was used, demonstrating that ERK-mediated MMP9 production and change in mitochondrial function was critical for the biological function of USP9X in prostate cancer cells. In conclusion, the present study demonstrated that USP9X is downregulated in prostate cancer and functions as an inhibitor of tumor cell invasion, possibly through the regulation of the ERK signaling pathway.

Prostate cancer cell proliferation is suppressed by microRNA-3160-5p via targeting of F-box and WD repeat domain containing 8

MicroRNAs (miRNAs/miRs), which are endogenous non-coding single-stranded RNAs 19-25 nucleotides in length, regulate gene expression by blocking translation or transcription repression. The present study revealed that miR-3160-5p was widely expressed in prostate cancer cells by reverse transcription-quantitative polymerase chain reaction. There was a negative association between the expression of miR-3160-5p and F-box and WD repeat domain containing 8 (Fbxw8) in prostate cancer DU145 cells. A luciferase activity assay was used to verify that Fbxw8 is the target of miR-3160-5p. In the present study, using MTT assay and cell cycle analysis, it was demonstrated that DU145 cell proliferation was repressed and the cell cycle was arrested in the G₂/M cell cycle phase with upregulation of miR-3160-5p. Subsequent studies demonstrated that miR-3160-5p regulated the progression of the cell cycle in DU145 prostate cancer cells when the expression levels of phosphorylated cell division cycle (CDC)2, CDC25C and cyclin B1 were directly inhibited. Taken together, these findings revealed the mechanism underlying the role of miR-3160-5p in regulating the proliferation of DU145 cells and indicated that miR-3160-5p may serve as a promising novel therapeutic tool for prostate cancer.

Variation in routine follow-up care after curative treatment for head-and-neck cancer: a population-based study in Ontario

Background

The actual practices of routine follow-up after curative treatment for head-and-neck cancer are unknown, and existing guidelines are not evidence-based.

Methods

This retrospective population-based study used administrative data to describe 5 years of routine follow-up care in 3975 head-and-neck cancer patients diagnosed between 2007 and 2012 in Ontario.

Results

The mean number of visits per year declined during the follow-up period (from 7.8 to 1.9, p < 0.001). The proportion of patients receiving visits in concordance with guidelines ranged from 80% to 45% depending on the follow-up year. In at least 50% of patients, 1 head, neck, or chest imaging test was performed in the first follow-up year; that proportion subsequently declined (p < 0.001). Factors associated with follow-up practices included comorbidity, tumour site, treatment, geographic region, and physician specialty (p < 0.05).

Conclusions

Given current practice variation and the absence of an evidence-based standard, the challenge in identifying a single optimal follow-up strategy might be better addressed with a harmonized approach to providing individualized follow-up care.

MiR-491-5p negatively regulates cell proliferation and motility by targeting PDGFRA in prostate cancer

MicroRNA-491-5p (miR-491-5p) has been implicated in several cancers; however, its role in human prostate cancer (PCa) remains unknown. In this study, we observed downregulation of miR-491-5p expression in PCa tissues and cell lines. CCK-8 and EdU assays showed that forced expression of miR-491-5p suppressed PCa cell proliferation, which was further confirmed in a cell cycle assay. Overexpression of miR-491-5p also reduced PCa cell migration and invasion abilities as indicated by Transwell assays. Additionally, miR-491-5p overexpression significantly inhibited PCa growth in a mouse xenograft model. Mechanistically, platelet-derived growth factor receptor α (PDGFRA) was found to be a novel target of miR-491-5p. Re-introduction of PDGFRA antagonized the inhibitory effects of miR-491-5p on the proliferation and motility abilities of PCa cells. In clinical samples of PCa, miR-491-5p was negatively correlated with PDGFRA expression, which was upregulated in PCa. Collectively, these results demonstrate that miR-491-5p acts as a tumor suppressor in PCa by directly targeting PDGFRA and may serve as a therapeutic biomarker for patients with PCa.

MiR-199a-3p suppresses proliferation and invasion of prostate cancer cells by targeting Smad1

OBJECTIVES

This study was intended to analyze effects of miR-199a-3p and Smad1 on proliferation, migration and invasion of prostate cancer (PCa) cells.

RESULTS

MiR-199a-3p was significantly decreased in PCa tissues in comparison to that in adjacent normal tissues (P < 0.05). Over-expressed miR-199a-3p markedly suppressed proliferation and invasion of PCa cells (P < 0.05). MiR-199a-3p was negatively correlated with Smad1 expression, and overexpression of Smad1 could antagonize the effects of miR-199a-3p on PCa cells.

MATERIALS AND METHODS

The PCa tissues and their adjacent normal tissues were collected from 54 PCa patients. Expressions of miR-199a-3p and Smad1 mRNA in tissues and cells were evaluated with real-time quantitative polymerase chain reaction (RT-qPCR), and immunohistochemistry assay was used to detect Smad1 protein expressions. The target relationship between miR-199a-3p and Smad1 was assessed by luciferase reporter assay. The PCa cell lines (i.e. PC-3 cells) were transfected with miR-199a-3p mimics and Smad1-cDNA. MTT and Transwell assays were applied to detect proliferative, migratory and invasive abilities of PCa cells.

CONCLUSIONS

MiR-199a-3p suppressed proliferation and invasion of PCa cells by targeting Smad1.

Urethral strictures after radiation therapy for prostate cancer

Urethral stricture after radiation therapy for localized prostate cancer is a delicate problem as the decreased availability of tissue healing and the close relation to the sphincter complicates any surgical approach. We here review the pathophysiology, dosimetry, and the disease specific aspects of urethral strictures after radiotherapy. Moreover we discuss different treatment option such as direct vision internal urethrotomy as well as techniques for open reconstruction with and without tissue transfer.