circ_WASF2 regulates ferroptosis by miR-634/ GPX4 signaling in pancreatic cancer.

PURPOSE: Pancreatic cancer (PC) is one of the most lethal malignant gastrointestinal tumors (GI) characterized by a poor prognosis. Ferroptosis is an emerging programmed cell death that plays an essential role in the progression of various cancers. Ferroptosis is driven by iron-dependent phospholipid peroxidation and is regulated by mitochondrial activity, lipid peroxidation, and reactive oxygen species (ROS). The function and mechanism of ferroptosis in PC need more research. METHODS: The levels of circRNAs, miRNAs, and mRNAs were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was used for protein detection. CCK8 assays were used to detect cell proliferation. Cell death, lipid peroxidation, ROS, and Fe2+ were detected by indicted kits. Dual-luciferase reporter and RNA pull-down assays were conducted to confirm the interaction between circRNAs, miRNAs, and mRNAs. RESULTS: In this research, we found that circular RNA hsa_circ_0000003(circ_WASF2) was upregulated in pancreatic cancer cells. The silence of circ_WASF2 inhibited cancer proliferation and increased cell death by increasing ferroptosis accompanied by up-regulation of lipid peroxidation, ROS, and Fe2+. Further studies showed that circ_WASF2 could attenuate ferroptosis by targeting miR-634 and the downstream glutathione peroxidase 4 (GPX4). GPX4 has been well-reported as a central factor in ferroptosis. Our research revealed a new pathway for regulating ferroptosis in PC. CONCLUSION: In summary, we have determined that circ_WASF2/miR-634/GPX4 contributed to ferroptosis-induced cell death, and provided a possible therapeutic target in PC.

Associations of fatty acids with the risk of biliary tract calculus and inflammation: a Mendelian randomization study.

BACKGROUND: The presence of gallstones in both the gallbladder and bile ducts is referred to as cholelithiasis. The prevalence of cholecystolithiasis and bile duct stones differs. Observational and Mendelian randomization (MR) studies have elucidated the significant contributing role of numerous fatty acids (FAs) in the development of cholelithiasis. Despite numerous studies about cholelithiasis, evidence on the relationship between serum FA levels and cholecystolithiasis, as well as bile duct stones with or without inflammation, remains insufficient. METHODS: A two-sample MR study was designed to clarify the impact of serum FA levels on various bile duct inflammatory diseases. The summary statistics of single nucleotide polymorphisms (SNPs) associated with fatty acids were obtained from the UK Biobank (UKB) and included data from 114,999 participants. The researchers obtained GWAS summary statistics for cholecystolithiasis and bile duct stones in 463,010 and 361,194 European participants, including cases with and without inflammation. No sample overlap between the exposure and outcome was verified through the "mr-lap" package. The SNPs were screened to identify instrumental variables (IVs). Cochran's Q test was applied for heterogeneity assessment. Inverse variance weighting (IVW) (fixed effects or random effects), MR-Egger regression and weighted median methods were used for MR. Multivariable MR was applied to determine the direct effect of each exposure on the outcome. A false discovery rate (FDR) was applied to adjust for multiple testing correction based on the Benjamini-Hochberg method. Finally, the FinnGen Consortium was used to validate some results. RESULTS: The overall concentration of polyunsaturated fatty acids (PUFAs) in the serum was negatively associated with the risk of calculus of the gallbladder with acute cholecystitis (IVW, OR = 0.996, P = 0.038, CI 0.992-0.999; weighted median, OR = 0.995, P = 0.025, CI 0.991-0.999). The percentage of PUFAs to total monounsaturated fatty acids(MUFAs) (IVW, OR = 0.998, P = 0.045, CI 0.997-0.999) and the percentage of PUFAs to total FAs (IVW, OR = 0.997, P = 0.025, CI 0.995-0.999) had a protective role against cholecystitis. The percentage of PUFAs to total FAs had a protective role against calculus of the gallbladder without cholecystitis (IVW, OR = 0.995, P = 0.026, CI 0.990-0.999; MR Egger, OR = 0.99, P = 0.03, CI 0.982-0.998; weighted median, OR = 0.991, P = 5.41e-06, CI 0.988-0.995). Conversely, the percentage of MUFAs to total FAs increased the risk for cholecystitis (IVW, OR = 1.001, P = 0.034, CI 1.0001-1.002). However, there were no causal effects of the above exposures on the outcomes through multivariable MR and multiple testing correction. Finally, the causal effects of the above exposures on cholecystitis were validated in the FinnGen Consortium, which suggested that the percentage of PUFAs to total FAs (IVW, OR = 0.744, P = 0.021, CI 0.579-0.957) had a protective role against cholecystitis. CONCLUSION: These Mendelian randomization findings suggested that more attention should be focused on people who have low serum PUFA levels, which may have a potential role in the occurrence of calculus of the gallbladder or cholecystitis rather than calculus of the bile duct without cholangitis or cholecystitis.

Exosomes derived from TGF-ß1-pretreated mesenchymal stem cells alleviate biliary ischemia-reperfusion injury through Jagged1/Notch1/SOX9 pathway.

BACKGROUND: This study aimed to evaluate the efficacy of exosomes (EXO) derived from TGF-ß1-pretreated mesenchymal stem cells (MSCs) on biliary ischemia reperfusion injury (IRI) and further reveal the possible mechanisms. METHODS: Bone marrow-derived MSCs were treated with exogenous TGF-ß1, Jagged1/Notch1/SOX9 pathway inhibitor LY450139, or their combination. Then, EXO were isolated from the culture supernatants and further characterized. After establishing IRI model of biliary epithelial cells (EpiCs), EXO derived from differently-treated MSCs were applied to detect their protective effects on EpiCs, and LY450139 was applied in EpiCs to detect the possible mechanisms after treatment with MSCs-EXO. EXO derived from differently-treated MSCs were further injected into the hepatic artery immediately after establishment of intrahepatic biliary IRI for animal studies. RESULTS: Pretreatment with TGF-ß1 significantly enhanced MSCs-EXO production and elevated the levels of massive miRNAs associated with anti-apoptosis and tissue repair, which were evidently decreased after TGF-ß1 plus LY450139 cotreatment. Notable improvement was observed in EpiCs after MSCs-EXO treatment, evidenced by reduced cellular apoptosis, increased cellular proliferation and declined oxidative stress, which were more evident in EpiCs that were treated with EXO derived from TGF-ß1-pretreated MSCs. However, application of EXO derived from TGF-ß1 plus LY450139-cotreated MSCs reversely enhanced cellular apoptosis, decreased cellular proliferation and anti-oxidants production. Interestingly, LY450139 application in EpiCs after treatment with MSCs-EXO also reversed the declined cellular apoptosis and enhanced oxidative stress induced by TGF-ß1 pretreatment. In animal studies, administration of EXO derived from TGF-ß1-pretreated MSCs more effectively attenuated biliary IRI through reducing oxidative stress, apoptosis, inflammation and enhancing the expression levels of TGF-ß1 and Jagged1/Notch1/SOX9 pathway-related markers, which were reversed after administration of EXO derived from TGF-ß1 plus LY450139-cotreated MSCs. CONCLUSION: Our results provided a vital insight that TGF-ß1 pretreatment endowed MSCs-EXO with stronger protective effects to improve biliary IRI via Jagged1/Notch1/SOX9 pathway.

Krüppel-like Factor 13 Promotes HCC Progression by Transcriptional Regulation of HMGCS1-mediated Cholesterol Synthesis.

Background and Aims: Krüppel-like factor (KLF) has a role in the occurrence, development and metabolism of cancer. We aimed to explore the role and potential molecular mechanism of KLF13 in the growth and migration of liver cancer cells. Methods: The expression of KLF13 in hepatocellular carcinoma (HCC) tissues was higher than that in normal tissues according to analysis of The Cancer Genome Atlas (TCGA) database. Lentiviral plasmids were used for overexpression and plasmid knockdown of KLF13. Real-time quantitative polymerase chain reaction (qPCR) and western blotting were used to detect mRNA and protein expression in HCC tissues and cells. Cell counting kit-8 (CCK-8), colony formation, cell migration and invasion, and flow cytometry assays were used to assess the in vitro function of KLF13 in HCC cells. The effect of KLF13 on xenograft tumor growth in vivo was evaluated. The cholesterol content of HCC cells was determined by an indicator kit. A dual-luciferase reporter assay and chromatin immunoprecipitation sequencing (ChIP-seq) revealed the binding relationship between KLF13 and HMGCS1. Results: The expression of KLF13 was upregulated in HCC tissues and TCGA database. KLF13 knockdown inhibited the proliferation, migration and invasion of HepG2 and Huh7 cells and increased the apoptosis of Huh7 cells. The opposite effects were observed with the overexpression of KLF13 in SK-Hep1 and MHCC-97H cells. The overexpression of KLF13 promoted the growth of HCC in nude mice and KLF13 transcription promoted the expression of HMGCS1 and the biosynthesis of cholesterol. KLF13 knockdown inhibited cholesterol biosynthesis mediated by HMGCS1 and inhibited the growth and metastasis of HCC cells. Conclusions: KLF13 acted as a tumor promoter in HCC by positively regulating HMGCS1-mediated cholesterol biosynthesis.

Evaluating the clinical feasibility: The direct bisulfite genomic sequencing for examination of methylated status of protocadherin10 (PCDH10) promoter to predict the prognosis of gastric cancer.

OBJECTIVE: To elucidate the clinical significance of the methylated status of CpG site count of PCDH10 promoter in the survival prediction in gastric cancer (GC). METHODS: In the previous study, we demonstrated that the methylated CpG site count was significantly associated with the overall survival (OS) of GC patients by using the bisulfite genomic sequencing (BGS) with no less than five clones per sample. It was so complex and expensive for patients to undergo the BGS clones. In this study, we detected the different CpG site counts (hypermethylated and hypomethylated) of PCDH10 DNA promoter in GC samples of 471 patients by directly bisulfite genomic sequencing (D-BGS) without any clone. Furthermore, we evaluated the relationships between the methylated status of PCDH10 promoter and OS. RESULTS: Two hundred and fifty-seven of 471 (54.6%) GC patients were identified to present with PCDH10 promoter methylation by D-BGS. Patients who presented with 5 or more methylated CpG site counts of PCDH10 promoter had significantly poorer prognosis than patients who with less than 5 methylated CpG site counts of PCDH10 promoter (p= 0.039). With the multivariate survival analysis, we demonstrated that T stage, N stage and the hypermethylated CpG site counts of PCDH10 DNA promoter were the independent predictors of OS of GC patients. In addition, the hypermethylated CpG site counts of PCDH10 DNA promoter had smaller Akaike information criterion (AIC) and Bayesian information criterion (BIC) values than the other two independent predictors of the OS, indicating the hypermethylated CpG site counts of PCDH10 DNA promoter as the best prognostic predictor of GC. CONCLUSIONS: Our present findings suggested that the hypermethylated CpG site counts of PCDH10 DNA promoter for evaluating the prognosis of GC was reasonable by using the D-BGS.

Evaluating the clinical feasibility: The direct bisulfite genomic sequencing for examination of methylated status of E3 ubiquitin ligase RNF180 DNA promoter to predict the survival of gastric cancer.

BACKGROUND: E3 ubiquitin ligase Ring finger protein 180 (RNF180) has been identified as a novel tumor suppressor in gastric cancer and the methylated CpG site count of RNF180 DNA promoter can predict the prognosis for gastric cancer patients. OBJECTIVE: In the previous study, we demonstrated that methylated CpG site count of RNF180 DNA promoter was significantly associated with the survival of patients with gastric cancer using the bisulfite genomic sequencing (BGS) in the gastric cancer tissue with five clones per sample. It was so complicate for each patient underwent the BGS detection with clones. It is important to explore a simple, rapid and accurate method to detect methylated CpG site count to predicting the prognosis for gastric cancer patients. METHODS: At present study, we detected hypermethylated and hypomethylated CpG site count of RNF180 DNA promoter in samples of 480 gastric cancer patients by direct bisulfite sequencing. RESULTS: We found that patients who possessed seven or less hypermethylated CpG sites of RNF180 DNA promoter had much better survival (p= 0.008), which was similar to our previous research results by using the BGS with clones. With the multivariate survival analysis, we found that T stage, N stage and hypermethylated CpG site count of RNF180 DNA promoter were the independent predictors of prognosis for gastric cancer patients. CONCLUSIONS: hypermethylated CpG site count of RNF180 DNA promoter for evaluating the prognosis of gastric cancer was reasonable by using the direct bisulfite sequencing.