Silencing immune-infiltrating biomarker CCDC80 inhibits malignant characterization and tumor formation in gastric cancer.

OBJECTIVE: Tumor immune infiltration leads to poor prognosis of gastric cancer patients and seriously affects the life quality of gastric cancer patients. This study was based on bioinformatics to screen prognostic biomarkers in patients with high degree of immune invasion of gastric cancer. Meanwhile, the action of biomarker CCDC80 was explored in gastric cancer by cell and tumorigenesis experiments, to provide reference for the cure of gastric cancer patients. METHODS: Data sets and clinical massage on gastric cancer were collected from TCGA database and GEO database. ConsensusClusterPlus was used to cluster gastric cancer patients based on the 28 immune cells infiltration in ssGSEA. R "Limma" package was applied to analyze differential mRNAs between Cluster 1 and Cluster 2. Differential expression genes were screened by single factor analysis. Stemness markers (SERPINF1, DCN, CCDC80, FBLN5, SPARCL1, CCL14, DPYSL3) were identified for differential expression genes. Prognostic value of CCDC80 was evaluated in gastric cancer. Differences in genomic mutation and tumor microenvironment immune infiltration were assessed between high or low CCDC80. Finally, gastric cancer cells (HGC-27 and MKN-45) were selected to evaluate the action of silencing CCDC80 on malignant characterization, macrophage polarization, and tumor formation. RESULTS: Bioinformatics analysis showed that CCDC80, as a stemness marker, was significantly overexpressed in gastric cancer. CCDC80 was also related to the degree of gastric cancer immune invasion. CCDC80 was up-expressed in cells of gastric cancer. Silencing CCDC80 inhibited malignant characterization and subcutaneous tumor formation of gastric cancer cells. High expression of CCDC80 was positive correspondence with immune invasion. Silencing CCDC80 inhibited M2 polarization and promoted M1 polarization in tumor tissues. In addition, gastric cancer patients were likely to have mutations in CDH1, ACTRT1, GANAB, and CDH10 genes in the High-CCDC80 group. CONCLUSION: Silencing CCDC80, a prognostic biomarker in patients with immune invasion of gastric cancer, could effectively inhibit the malignant characterization, M2 polarization, and tumor formation of gastric cancer.

Identifying potential anti-metastasis drugs for prostate cancer through integrative bioinformatics analysis and compound library screening.

BACKGROUND: Metastasis poses the greatest threat to the lives of individuals with prostate cancer. Therefore, it is imperative to identify the underlying mechanism driving metastasis. Doing so would facilitate the detection of new diagnostic biomarkers and the advancement of treatment options for patients. METHODS: Metastasis-related modules were identified through weighted gene co-expression network analysis based on microarray GSE6919. Hub genes were confirmed by quantitative real-time PCR across different prostate cell lines and clinic samples. Pivotal genes were determined through integration of RNA and transcription factor-target associated interactions. To predict drugs with potential to suppress tumor metastasis, we applied molecular networks using the DrugBank database. Drug repositioning analysis and confirmation of drug screen were conducted using the compound library. Confirmation of selective cytotoxicity of cupric oxide was carried out via invasion, transwell and apoptosis assays. RESULTS: We identified five metastasis-related modules. Of these modules, two were identified to represent core dysfunction modules in which five hub genes were determined for each module. Five of these 10 genes correlating with prostate cancer progression. Furthermore, our analysis revealed that there are 36 drugs with the potential to be active against tumor metastasis. Finally, we identified four compounds that have not previously been reported to have any association with cancer therapy. Of these, cupric oxide was determined to have the best chemotherapeutic potential in treating prostate cancer metastasis. CONCLUSIONS: By combining bioinformatics methods with compound library screening, this study proposes a valuable approach to drug discovery. Cupric oxide showed the potential in the treatment of prostate cancer metastasis and deserves further study.

Extrinsic apoptosis and senescence involved in growth kinetics of seminoma to cisplatin.

Seminoma is the most common type of testicular germ cell tumour and is highly sensitive to cisplatin therapy, which has not been fully elucidated. In this study, we comprehensively monitored dynamic changes of TCam-2 cells after cisplatin treatment. At an early stage, we found that both low and high concentrations of cisplatin induced the S-phase arrest in TCam-2 cells. By contrast, the G0G1 arrest was caused by cisplatin in teratoma NTERA-2 cells. Afterwards, high concentrations of cisplatin promoted the extrinsic apoptosis and high expressions of related genes (Fas/FasL-caspase-8/-3) in TCam-2 cells. However, when decreasing the cisplatin, the apoptotic cells were significantly reduced, and accompanied by cells showing senescence-like morphology, positive SA-ß-gal staining and up-regulation of senescence-related genes (p53, p21 and p16). Furthermore, the cell cycle analysis revealed that most of the senescent TCam-2 cells were irreversibly arrested in the G2M phase. G2M arrest was also observed in NTERA-2 cells treated with a low concentration of cisplatin, while no senescence-related phenotype was discovered. In addition, we detected the γ-H2AX, a DNA damage marker protein, and reactive oxygen species (ROS) and found both of which were elevated with the increase of cisplatin in TCam-2 cells. In conclusion, the extrinsic apoptosis and senescence are involved in the growth kinetics of TCam-2 cells to cisplatin, which provide some implications for studies on cisplatin and seminoma.

Factors influencing intercourse frequency among the young and middle-aged men. / å½±å“ä¸­é’å¹´ç”·æ€§æˆ¿äº‹é¢‘çŽ‡çš„å› ç´ .

OBJECTIVES: At present, there are few studies on the sexual activity of young and middle-aged men in China. This study aims to explore the factors that affect the frequency of intercourse among young and middle-aged men in China. METHODS: Data for 923 men aged 20-60 years were collected in the Health Management Center, Third Xiangya Hospital, Central South University from January 2019 to March 2019, and a questionnaire survey (including basic conditions and sexual function-related scales) was carried out in the subjects. Finally, the data were analyzed by multivariate logistic regression analysis. RESULTS: The age ( P <0.01), number of children ( P <0.01), total cholesterol ( P <0.05), low-density lipoprotein ( P <0.05), erectile function ( P <0.01) and premature ejaculation ( P <0.05) was significantly correlated with the frequency of intercourse in the young and middle-aged men in China. CONCLUSIONS: The sexual frequency in the middle-young men in China is closely related to factors such as age, number of children, total cholesterol, low-density lipoprotein, and sex function.

METTL3 potentiates resistance to cisplatin through m6 A modification of TFAP2C in seminoma.

Testicular germ cell tumours (TGCTs) rank as the most common malignancy in men aged 20-34 years, and seminomas are the most type of TGCTs. As a crucial anti-tumour agent with explicit toxicity, cisplatin may render resistance through intertwined mechanisms, even in disease entities with high curative ratio, such as seminoma. Previously, we established cisplatin-resistant seminoma TCam-2 (TCam-2/CDDP) cells and showed that epigenetic regulations, such as non-coding RNA (ncRNA) interactions, might orchestrate cell fate decisions in the cisplatin treatment context in seminoma. N6-methyladenosine (m6A) is the most prevalent internal modification in mRNA. In the present study, we assessed cisplatin resistance in seminoma from the perspective of m6 A, another manner of epigenetic modification. The global m6 A enrichment of TCam-2 and TCam-2/CDDP was depicted. Then, we elucidated whether transcription factor-activating enhancer-binding protein 2C (TFAP2C) was functionally m6 A-modified by methyltransferase-like protein 3 (METTL3), which acted as an m6 A 'writer', and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), which acted as an m6 A 'reader'. Enhanced stability of TFAP2C mRNA promoted seminoma cell survival under cisplatin treatment burden probably through up-regulation of DNA repair-related genes. Hopefully, this study will help improve our understanding of the subtleties of the tumour cellular coping strategy in response to chemotherapy. Targeting factors that are involved in m6 A methylation may be an effective strategy for circumventing cisplatin resistance in seminoma.

Association of genetic variations of 3'-UTR in clopidogrel pharmacokinetic-relevant genes with clopidogrel response in Han Chinese patients with coronary artery disease.

Dual antiplatelet therapy with aspirin and clopidogrel has reduced ischemic vascular events significantly. Genetic influence, especially those in clopidogrel pharmacokinetic-relevant genes partially accounts for interindividual pharmacodynamic variability of clopidogrel. However, most studies have concentrated on the genetic variations in introns, exons, or promoters of the candidate genes, and the association between genetic variations in 3'-UTR in clopidogrel pharmacokinetic-relevant genes and clopidogrel response is unknown. In our study, ten different algorithms were applied to pick potential miRNAs targeting the clopidogrel pharmacokinetic-relevant genes. Furthermore, the correlation between miRNA expression profiles and mRNA expression of corresponding clopidogrel pharmacokinetic-relevant genes was analyzed. Through comprehensive analysis, including bioinformatics prediction and correlation analysis of miRNA and mRNA expression profiles, miR-218-5p and miR-506-5p were supposed to regulate the expression of PON1 via binding with its 3'-UTR. Moreover, PON1 rs854551 and rs854552 were located in miRNA recognizing sequences and may serve as potential miRSNPs possibly affecting PON1 expression. The rs854552 polymorphism was genotyped and platelet reactivity index (PRI) indicative of clopidogrel response was measured in 341 Chinese coronary artery disease (CAD) patients 24 h after administration of 300 mg clopidogrel. Our results showed that PON1 rs854552 had a significant influence on PRI in CAD patients, especially in patients with CYP2C19 extensive metabolic phenotype. In conclusion, PON1 rs854552 polymorphisms may affect clopidogrel response. Bioinformatics prediction followed by functional validation could aid in decoding the contribution of unexplained variations in the 3'-UTR in drug-metabolizing enzymes on clopidogrel response.

Characterization of Potting Epoxy Resins Performance Parameters Based on a Viscoelastic Constitutive Model.

To describe the evolution of residual stresses in epoxy resin during the curing process, a more detailed characterization of its viscoelastic properties is necessary. In this study, we have devised a simplified apparatus for assessing the viscoelastic properties of epoxy resin. This apparatus employs a confining cylinder to restrict the circumferential and radial deformations of the material. Following the application of load by the testing machine, the epoxy resin sample gradually reduces the gap between its surface and the inner wall of the confining cylinder, ultimately achieving full contact and establishing a continuous interface. By recording the circumferential stress-strain on the outer surface of the confining cylinder, we can deduce the variations in material bulk and shear moduli with time. This characterization spans eight temperature points surrounding the glass transition temperature, revealing the bulk and shear relaxation moduli of the epoxy resin. Throughout the experiments, the epoxy resin's viscoelastic response demonstrated a pronounced time-temperature dependency. Below the glass transition temperature, the stress relaxation response progressively accelerated with increasing temperature, while beyond the glass transition temperature, the stress relaxation time underwent a substantial reduction. By applying the time-temperature superposition principle, it is possible to construct the relaxation master curves for the bulk and shear moduli of the epoxy resin. By fitting the data, we can obtain expressions for the constitutive model describing the viscoelastic behavior of the epoxy resin. In order to validate the reliability of the test results, a uniaxial tensile relaxation test was conducted on the epoxy resin casting body. The results show good agreement between the obtained uniaxial relaxation modulus curves and those derived from the bulk and shear relaxation modulus equations, confirming the validity of both the device design and the testing methodology.

Novel Hybrid Modeling and Analysis Method for Steam Reforming Solid Oxide Fuel Cell System Multifault Degradation Fusion Assessment.

Steam reforming solid oxide fuel cell (SOFC) systems are important devices to promote carbon neutralization and clean energy conversion. It is difficult to monitor system working conditions in real time due to the possible fusion fault degradation under high temperatures and the seal environment, so it is necessary to design an effective system multifault degradation assessment strategy for solid oxide fuel cell systems. Therefore, in this paper, a novel hybrid model is developed. The hybrid model is built to look for the system fault reason based on first principles, machine learning (radial basis function neural network), and a multimodal classification algorithm. Then, stack, key balance of plant components (afterburner, heat exchanger, and reformer), thermoelectric performance, and system efficiency are studied during the progress of the system experiment. The results show that the novel hybrid model can track well the system operation trend, and solid oxide fuel cell system working dynamic performance can be obtained. Furthermore, four fault types of solid oxide fuel cell systems are analyzed with thermoelectric parameters and energy conversion efficiency based on transition and fault stages, and two cases are also successful by using the built model to decouple the multifault degradation fusion. In addition, the solid oxide fuel cell multifault degradation fusion assessment method proposed in this paper can also be used in other fuel cell systems.

Factors associated with anxiety and depression in patients with erectile dysfunction: a cross-sectional study.

BACKGROUND: Few studies have investigated factors associated with anxiety and depression among patients with erectile dysfunction (ED). This study aimed to investigate associated factors and the prevalence of anxiety and depression in this special group in China. METHODS: Data from 511 patients with ED aged 18-60 years were collected between July 2021 and April 2022. The 5-item International Index of Erectile Function (IIEF-5) questionnaire, self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were used to evaluate erectile function, anxiety and depression, respectively. Univariate analysis and multivariate linear regression analyses were used to explore the associated factors of depression and anxiety. RESULTS: The prevalence of anxiety and depression among ED patients was 38.16% and 64.97%, respectively. The mean anxiety index score was 47.37 ± 6.69 points, and the mean depression index was 54.72 ± 9.10 points. Multiple linear regression analysis showed that worse ED, low education level, and smoking were positively associated with increased risk of anxiety and depression. In addition, younger age, longer onset time, and irregular sleep were positively associated with high risk of anxiety, and irregular exercise was associated with severe depression. CONCLUSIONS: The prevalence of depression and anxiety in ED patients is high, and the severity of ED, age, education level, smoking, onset time, regular sleep, and exercise were associated with anxiety or depression. Reversible risk factors should be avoided and individualized psychological support services are necessary for ED patients.

Cisplatin causes erectile dysfunction by decreasing endothelial and smooth muscle content and inducing cavernosal nerve senescence in rats.

Introduction: Cisplatin (cis-diamminedichloroplatinum II, CDDP), a drug widely used for cancer worldwide, may affect erectile function, but its side effects have not received enough attention. To investigate the effect of CDDP on erectile function and its possible mechanism. Methods: Sprague-Dawley rats were intraperitoneally administered CDDP (CDDP group) or the same volume of normal saline (control group). Erectile function was evaluated after a one-week washout. Then, histologic changes in the corpus cavernosum and cavernous nerve (CN) were measured. Other Sprague-Dawley rats were used to isolate the major pelvic ganglion and cavernous nerve (MPG/CN). RSC96 cells were then treated with CDDP. SA-ß-gal staining was used to identify senescent cells, and qPCR was used to detect the senescence-associated secretory phenotype (SASP). Finally, the supernatant of RSC96 cells was used to culture MPG/CN. Erectile function was measured after administration of CDDP. The cavernosum levels of α-SMA, CD31, eNOS, and γ-H2AX, the apoptosis rate and the expression of p16, p21 and p53 in CN were also assayed. The senescent phenotype of RSC96 cells treated with CDDP was identified, and neurite growth from the MPG/CN was photographed and measured. Results: The CDDP group had a significantly lower ICP/MAP ratio than the control group. Compared to the control group, the CDDP group exhibited significantly lower α-SMA, CD31 and eNOS levels and significantly higher γ-H2AX and apoptosis rates in corpus cavernosum. In addition, CDDP increased some senescence markers p16, p21 and p53 in CN. In vitro, CDDP induced RSC96 senescence and SASP, and the supernatant of senescent cells slowed neurite outgrowth of MPG/CN. Discussions: CDDP treatment could induce erectile dysfunction, by affecting the content of endothelial and smooth muscle and causing SASP in CN. The results indicate that CDDP treatment should be considered as a risk factor for ED. Clinicians should pay more attention to the erectile function of cancer patients who receive CDDP treatment.

eIF3f Mediates SGOC Pathway Reprogramming by Enhancing Deubiquitinating Activity in Colorectal Cancer.

Numerous studies have demonstrated that individual proteins can moonlight. Eukaryotic Initiation translation factor 3, f subunit (eIF3f) is involved in critical biological functions; however, its role independent of protein translation in regulating colorectal cancer (CRC) is not characterized. Here, it is demonstrated that eIF3f is upregulated in CRC tumor tissues and that both Wnt and EGF signaling pathways are participating in eIF3f's oncogenic impact on targeting phosphoglycerate dehydrogenase (PHGDH) during CRC development. Mechanistically, EGF blocks FBXW7ß-mediated PHGDH ubiquitination through GSK3ß deactivation, and eIF3f antagonizes FBXW7ß-mediated PHGDH ubiquitination through its deubiquitinating activity. Additionally, Wnt signals transcriptionally activate the expression of eIF3f, which also exerts its deubiquitinating activity toward MYC, thereby increasing MYC-mediated PHGDH transcription. Thereby, both impacts allow eIF3f to elevate the expression of PHGDH, enhancing Serine-Glycine-One-Carbon (SGOC) signaling pathway to facilitate CRC development. In summary, the study uncovers the intrinsic role and underlying molecular mechanism of eIF3f in SGOC signaling, providing novel insight into the strategies to target eIF3f-PHGDH axis in CRC.

Comparison of characteristics between Chinese diabetes mellitus-induced erectile dysfunction populations and non-diabetes mellitus-induced erectile dysfunction populations: A cross-sectional study.

Background: Erectile dysfunction (ED) is a common disease in adult men, and diabetes is an independent risk factor for ED. However, there are few reports on the distinction between diabetes mellitus-induced erectile dysfunction (DMED) and non-DMED features, as well as ED features of varying severity in the two groups. Methods: A total of 365 ED patients treated at two clinics in China from 2019 to 2022 were included. Questionnaires of the International Index of Erectile Function (IIEF-5), Erectile Hardness Score (EHS), Premature Ejaculation Diagnostic Tool (PEDT), Patient Health Questionnaire-9 (PHQ-9), and Generalized Anxiety Disorder-7 (GAD-7) were administered to the patients. They were divided into three groups according to the IIEF-5 score: 5-7 for severe ED, 8-11 for moderate ED, and 12-21 for mild ED. In addition, the patient's age, weight, height, fasting blood glucose (FBG), total cholesterol (TC), triglycerides (TG), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), total testosterone (TT) and other indicators were also collected. Statistical analysis was performed using SPSS 26, comparing all parameters between groups. Results: Age (P<0.001), height (P=0.009), body mass index (BMI) (P=0.002), PEDT (P<0.001), FBG (P<0.001), FSH (P<0.001), TG (P<0.001), TT (P<0.001) and triglyceride-glucose index (TyG) (P<0.001) were significantly different between diabetic ED and nondiabetic ED subjects. The trend test in the nondiabetic ED population found a negative correlation between the IIEF-5 score and PHQ-9 (P for trend=0.15). Multivariate ordinal logistic regression in the diabetic ED population showed that elevated LH OR=11.37 (95% CI: 0.966, 3.897) and elevated PRL OR=4.10 (95% CI: 0.410, 2.411) were associated with an increased risk of more severe ED. Conclusions: The aetiology, demographic parameters, degree of premature ejaculation, and related biochemical tests were significantly different between the DMED and non-DMED populations.

Tetrathiomolybdate Partially Alleviates Erectile Dysfunction of Type 1 Diabetic Rats Through Affecting Ceruloplasmin/eNOS and Inhibiting Corporal Fibrosis and Systemic Inflammation.

INTRODUCTION: Patients with erectile dysfunction induced by diabetes mellitus (DMED) show a poor effect rate for oral phosphodiesterase type 5 inhibitors (PDE5is). Therefore, the new therapeutic strategy is necessary in patients with DMED. AIM: To investigate whether Tetrathiomolybdate (TM) supplementation could ameliorate DMED by activation of eNOS. METHODS: Twenty-four diabetic rats were induced by intraperitoneal injection of streptozotocin (STZ) and the other 6 normal rats constituted the control group. Eight weeks later, the erectile function of rats was assessed with an apomorphine test. Only some rats with DMED were treated with TM orally every day for 4 weeks; the other rats remained in the same condition for 4 weeks. After 1 week washout, the erectile function of rats in each group was evaluated. Then, the serum concentration of IL-6 and histologic changes of corpus cavernosum were measured. MAIN OUTCOME MEASURE: Erectile function was measured after DMED rats treated with TM. The cavernosum level of Ceruloplasmin (Cp), eNOS, endothelial cell content, corporal fibrosis, apoptosis rate and the serum level of IL-6 were also assayed. RESULTS: Erectile function in the DMED group was significantly impaired compared with the control group and was partly, but significantly, improved in the DMED+TM group. The DMED group showed upregulation of Cp and inhibition of eNOS, but the inhibition was partly reversed in the DMED+TM group. The DMED group showed serious corporal fibrosis. However, TM supplementation partly increased the ratio of smooth muscle to collagen, decreased the ratio of apoptosis. What's more, gavage administration of TM profoundly decreased the serum level of IL-6 in DMED rats. CONCLUSION: TM supplementation inhibits endothelial dysfunction, corporal fibrosis, and systemic inflammation, ultimately leading to partial improvement of DMED in rats. Yin Y, Peng J, Zhou J, et al., Tetrathiomolybdate Partially Alleviates Erectile Dysfunction of Type 1 Diabetic Rats Through Affecting Ceruloplasmin/eNOS and Inhibiting Corporal Fibrosis and Systemic Inflammation. Sex Med 2022;10:100455.

Roles of lncRNA LVBU in regulating urea cycle/polyamine synthesis axis to promote colorectal carcinoma progression.

Altered expression of Urea Cycle (UC) enzymes occurs in many tumors, resulting a metabolic hallmark termed as UC dysregulation. Polyamines are synthesized from ornithine, and polyamine synthetic genes are elevated in various tumors. However, the underlying deregulations of UC/ polyamine synthesis in cancer remain elusive. Here, we characterized a hypoxia-induced lncRNA LVBU (lncRNA regulation via BCL6/urea cycle) that is highly expressed in colorectal cancer (CRC) and correlates with poor cancer prognosis. Increased LVBU expression promoted CRC cells proliferation, foci formation and tumorigenesis. Further, LVBU regulates urea cycle and polyamine synthesis through BCL6, a negative regulator of p53. Mechanistically, overexpression of LVBU competitively bound miR-10a/miR-34c to protect BCL6 from miR-10a/34c-mediated degradation, which in turn allows BCL6 to block p53-mediated suppression of genes (arginase1 ARG1, ornithine transcarbamylase OTC, ornithine decarboxylase 1 ODC1) involved in UC/polyamine synthesis. Significantly, ODC1 inhibitor attenuated the growth of patient derived xenografts (PDX) that sustain high LVBU levels. Taken together, elevated LVBU can regulate BCL6-p53 signaling axis for systemic UC/polyamine synthesis reprogramming and confers a predilection toward CRC development. Our data demonstrates that further drug development and clinical evaluation of inhibiting UC/polyamine synthesis are warranted for CRC patients with high expression of LVBU.

What Influences Coital Frequency Among Chinese Men?: A Cross-Sectional Study.

INTRODUCTION: There are many Western reports on factors influencing coital frequency among men. However, no articles could be found about the factors influencing sexual activity among Chinese men. AIM: The aim of this study was to identify the factors that influence the coital frequency of Chinese men. MAIN OUTCOME MEASURES: The main outcome measures included self-reported monthly coital frequency, age, occupation, education level, andrology-related scales and dietary habits. METHODS: Data for 1,407 men aged 18-79 years were collected in the Health Management Center of the Third Xiangya Hospital of Central South University from January 2019 to May 2019. The respondents completed the questionnaires independently or with the help of an interviewer (who read or explained the questionnaires to them) to analyse the factors that influence coital frequency. RESULTS: In the previous 6 months, the sample had a mean monthly coital frequency (±SD) of 4.34 ± 3.18. Univariate logistic regression results indicated that the number of children (P = 0.004), IIEF-5 scores (P <0.001), EHSs (P <0.001) and frequency of milk consumption (P = 0.001) were associated with more frequent sexual activity. These statistical associations did not change after further adjustment for age, occupation, and reproductive history. We observed that the frequency of sexual activity showed an increasing trend with a greater number of children, higher IIEF-5 scores, higher EHSs and greater frequency of milk consumption (test for trend, P<0.05). Both univariate and multivariate analysis results indicated that the frequency of sexual activity decreased with increasing age (test for trend, P<0.001). CONCLUSION: The coital frequency of Chinese men is associated with erectile function, anthropometric parameters, age, occupation, and dietary habits. Xiang Y, Peng J, Yang J, et al. What Influences Coital Frequency Among Chinese Men?: A Cross-Sectional Study. Sex Med 2021;9:100363.

The m6A methyltransferase METTL3 regulates autophagy and sensitivity to cisplatin by targeting ATG5 in seminoma.

BACKGROUND: Our previous work shows Autophagy enhanced resistance to cisplatin in seminoma. The expression of the N6-methyladenosine (m6A) methyltransferases METTL3 was significantly increased in the cisplatin-resistant TCam-2 cell line of seminoma. We aimed to investigate the role of m6A methylation in autophagy and the chemosensitivity of seminoma cells. METHODS: Plasmid and siRNA were used to overexpress and knockdown METTL3. Autophagy was detected by western blot and immunofluorescence, respectively. The expression of downstream targets of METTL3 was detected by quantitative real-time PCR (qRT-PCR) and western blot, and the m6A level of them was detected by MeRIP-qPCR. Chemosensitivity of the TCam-2 cell line was identified through MTT assay. RESULTS: Upon METTL3 overexpression, autophagy of TCam-2 cell line was enhanced and its sensitivity to cisplatin was decreased. The use of autophagy inhibitors 3-methyladenine (3-MA) could reverse the protective effect of METTL3 on TCam-2 cells. We found that the up-regulation of METTL3 could increase the m6A modification level of ATG5 transcript, thus increased expression of ATG5. Moreover, knockdown of ATG5 reduced METTL3-induced autophagy, suggesting that ATG5 was a potential target for METTL3 to promote autophagy. CONCLUSIONS: In summary, our research unveiled the unique mechanism by which m6A methylation regulates autophagy and chemosensitivity of the TCam-2 cell line and METTL3 was a potential target to overcome the cisplatin resistance of seminoma.