OBJECTIVE: To explore the potential role of mRNA m7G modification in the pathogenesis of human adenocarcinoma of esophagogastric junction (AEG). METHODS: Pathological tissue specimens from four AEG patients who underwent surgical treatment at the People's Hospital Affiliated to Jiangsu University between 2018 and 2019 were selected. Tumor tissues and adjacent normal tissues were collected from these patients. RNA was extracted from both tissue types and subjected to m7G methylated RNA immunoprecipitation sequencing (m7G-MeRIP-seq) to analyze the patterns of m7G modification, the characteristics of differential m7G modification sites, the differentially expressed mRNA, and the correlation between m7G modification and mRNA expression levels. Differential m7G-modified genes (MSH6, BRCA1, and SOX9) were further validated using methylated RNA immunoprecipitation quantitative PCR (MeRIP-qPCR), while the expression of METTL1 and WDR4 genes was examined by real-time quantitative PCR (RT-qPCR). This study was approved by the Medical Ethics Committee of the People's Hospital Affiliated to Jiangsu University (Ethics No. 20150083). RESULTS: m7G-MeRIP-seq analysis revealed that m7G modifications in both AEG and adjacent normal tissues were predominantly located in the GC-rich region surrounding the internal start codon of mRNA. Differential m7G modification sites between the two groups were closely associated with cancer-related genes. mRNA library analysis showed that differentially expressed mRNA were predominantly upregulated in AEG tissues and downregulated in adjacent normal tissues. Cross-analysis indicated that genes with hypermethylation tended to exhibit upregulated expression, while genes with hypomethylation were typically downregulated in AEG tissues. MeRIP-qPCR validation confirmed that the mRNA expression of MSH6, BRCA1, and SOX9 were significantly upregulated in AEG tissues compared to adjacent normal tissues (AEG vs. normal, P < 0.05). RT-qPCR results demonstrated that the mRNA expression levels of METTL1 and WDR4 were also upregulated in AEG tissues (AEG vs. normal, P < 0.000 5). CONCLUSION These findings suggest that mRNA m7G modification plays a significant role in the development of AEG. Furthermore, proteins as METTL1 and WDR4 may facilitate AEG progression by regulating mRNA m7G modification. These results provide valuable insights into the molecular mechanisms underlying AEG and may inform future therapeutic strategies for this malignancy.
Humans ; RNA, Messenger/metabolism* ; Adenocarcinoma/pathology* ; Esophagogastric Junction/metabolism* ; Esophageal Neoplasms/metabolism* ; Gene Expression Regulation, Neoplastic ; Female ; Male ; Middle Aged ; DNA Methylation ; Methyltransferases/metabolism* ; Stomach Neoplasms/genetics*

OBJECTIVES: To investigate the mechanism by which circ_EPHB4 regulates temozolomide (TMZ) sensitivity of glioma cells through the miR-424-5p/Wnt3 signal axis. METHODS: We detected the expression levels of circ_EPHB4, miR-424-5p and Wnt3 mRNA in glioma specimens from 25 patients with primary glioma and 25 patients experiencing relapse following temozolomide-based chemotherapy and in TMZ-sensitive and -resistant glioma A172 and SHG44 cells with circ_EPHB4 knockdown using qRT-PCR, and Wnt3 protein expression level was detected with Western blotting. Cell viability, colony-forming ability, and apoptosis of the cells with circ_EPHB4 knockdown were assessed, and the targeted regulation relationship between circ_EPHB4, miR-424-5p, and Wnt3 was verified by dual luciferase reporter assay and RNA immunoprecipitation (RIP) experiments. The effect of circ_EPHB4 knockdown on tumorigenesis of glioma cells was evaluated in subcutaneous tumor-bearing nude mouse models. RESULTS: The expression of circ_EPHB4 was significantly increased in glioma tissues and cells as compared with normal neural tissues and astrocytes (P=0.014). In TMZ-resistant glioma cells, circ_EPHB4 knockdown resulted in an obvious reduction of IC50 value of TMZ, inhibited cell colony formation, and promoted cell apoptosis, and these effects were reversed by miR-424-5p knockdown. The expressions of miR-424-5p and circ_EPHB4 were negatively correlated in glioma tissues (P=0.011). MiR-424-5p knockdown also attenuated the effect of circ_EPHB4 knockdown on expressions of PCNA, P-gp, MRP1 and bax. CONCLUSIONS Circ_EPHB4 regulates Wnt3 expression through "sponge adsorption" of miR-424-5p, thereby modulating TMZ-resistant glioblastoma cell clonogenesis, apoptosis, and TMZ sensitivity, suggesting the potential of circ_EPHB4 as a therapeutic target for reversing drug resistance of gliomas.
MicroRNAs/genetics* ; Humans ; Temozolomide ; Glioma/genetics* ; Animals ; Mice, Nude ; Cell Line, Tumor ; Wnt3 Protein/metabolism* ; Mice ; Apoptosis ; RNA, Circular ; Drug Resistance, Neoplasm ; Brain Neoplasms/pathology* ; Signal Transduction

OBJECTIVES: To investigate the mechanism through which salidroside inhibits proliferation of gastric cancer (GC) cells focusing on glucose metabolic reprogramming pathways. METHODS: High-throughput sequencing combined with bioinformatics analysis was employed to identify the potential targets of salidroside in human GC MGC-803 cells. Liposome-mediated transfection experiments were carried out to validate the functional and mechanistic roles of these targets. CCK-8 and colony formation assays were used to assess the effects of salidroside on GC cell viability and clonogenic ability. qRT-PCR, Western blotting, and biochemical assay kits were used to analyze the regulatory effects of salidroside on the miR-1343-3p-OGDHL/PDHB enzyme complex-pyruvate metabolic pathway in GC cells. RESULTS: Bioinformatics analysis suggested that the tumor-suppressive factor miR-1343-3p negatively regulated the key glycolytic enzyme gene oxoglutarate dehydrogenase-like (OGDHL) in GC cells, and OGDHL and pyruvate dehydrogenase E1 subunit beta (PDHB) were both significantly upregulated in GC tissues, which was close by correlated with reduced survival rates of GC patients. In MGC-803 cells, salidroside treatment significantly enhanced the expression level of miR-1343-3p and downregulated OGDHL expression, resulting in disruption of the stability of PDHB, reduced pyruvate oxidative decarboxylation, and consequently decreased production of acetyl-CoA and ATP. CONCLUSIONS Salidroside inhibits GC cell proliferation possibly by regulating the miR-1343-3p-OGDHL/PDHB enzyme complex-pyruvate metabolic pathway, which provides new insights into its anti-tumor mechanisms and suggests new strategies for targeted therapy for GC.
Humans ; Stomach Neoplasms/pathology* ; MicroRNAs/genetics* ; Cell Proliferation/drug effects* ; Glucosides/pharmacology* ; Phenols/pharmacology* ; Cell Line, Tumor ; Glucose/metabolism* ; Pyruvate Dehydrogenase (Lipoamide)/metabolism*

Hypoxia and aberrant activation of epidermal growth factor receptor (EGFR) are considered important features of various malignancies. However, whether hypoxia can directly trigger EGFR activation and its clinical implications remain unclear. In this study, we demonstrated that in oral cancer, a typical hypoxic tumor, hypoxia can induce chronic but constitutive phosphorylation of wild-type EGFR in the absence of ligands. Oral cancer cell lines exhibit different EGFR phosphorylation responses to hypoxia. In hypoxic HN4 and HN6 cells, ubiquitination-mediated endocytosis, lysosomal sorting, and degradation lead to low levels of EGFR phosphorylation. However, in CAL-27 and HN30 cells, a novel HIF-1α-induced long noncoding RNA (lncRNA), EUDAL, can compete with the E3 ligase/adaptor complex c-Cbl/Grb2 for binding to EGFR, stabilizing phosphorylated EGFR (pEGFR) and resulting in sustained activation of EGFR and its downstream STAT3/BNIP3 signaling. STAT3/BNIP3-mediated autophagy leads to antitumor drug resistance. A high EUDAL/EGFR/STAT3/autophagy pathway activation predicts poor response to chemotherapy in oral cancer patients. Collectively, hypoxia can induce noncanonical ligand-independent EGFR phosphorylation. High EUDAL expression facilitates sustained EGFR phosphorylation in hypoxic tumor cells and leads to autophagy-related drug resistance.
Humans ; ErbB Receptors/metabolism* ; Mouth Neoplasms/pathology* ; RNA, Long Noncoding/genetics* ; Drug Resistance, Neoplasm/genetics* ; Cell Line, Tumor ; Phosphorylation ; Signal Transduction ; STAT3 Transcription Factor/metabolism* ; Cell Hypoxia ; Autophagy ; Proto-Oncogene Proteins c-cbl/metabolism*

Adenosine-to-inosine (A-to-I), one of the most prevalent RNA modifications, has recently garnered significant attention. The A-to-I modification actively contributes to biological and pathological processes by affecting the structure and function of various RNA molecules, including double-stranded RNA, transfer RNA, microRNA, and viral RNA. Increasing evidence suggests that A-to-I plays a crucial role in the development of human disease, particularly in cancer, and aberrant A-to-I levels are closely associated with tumorigenesis and progression through regulation of the expression of multiple oncogenes and tumor suppressor genes. Currently, the underlying molecular mechanisms of A-to-I modification in cancer are not comprehensively understood. Here, we review the latest advances regarding the A-to-I editing pathways implicated in cancer, describing their biological functions and their connections to the disease.
Humans ; Adenosine/genetics* ; Inosine/genetics* ; RNA Editing ; Neoplasms/pathology* ; Animals ; MicroRNAs/metabolism*

Glutamine provides carbon and nitrogen to support the proliferation of cancer cells. However, the precise reason why cancer cells are particularly dependent on glutamine remains unclear. In this study, we report that glutamine modulates the tumor suppressor F-box and WD repeat domain-containing 7 (FBW7) to promote cancer cell proliferation and survival. Specifically, lysine 604 (K604) in the sixth of the 7 substrate-recruiting WD repeats of FBW7 undergoes glutaminylation (Gln-K604) by glutaminyl tRNA synthetase. Gln-K604 inhibits SCFFBW7-mediated degradation of c-Myc and Mcl-1, enhances glutamine utilization, and stimulates nucleotide and DNA biosynthesis through the activation of c-Myc. Additionally, Gln-K604 promotes resistance to apoptosis by activating Mcl-1. In contrast, SIRT1 deglutaminylates Gln-K604, thereby reversing its effects. Cancer cells lacking Gln-K604 exhibit overexpression of c-Myc and Mcl-1 and display resistance to chemotherapy-induced apoptosis. Silencing both c-MYC and MCL-1 in these cells sensitizes them to chemotherapy. These findings indicate that the glutamine-mediated signal via Gln-K604 is a key driver of cancer progression and suggest potential strategies for targeted cancer therapies based on varying Gln-K604 status.
Glutamine/metabolism* ; Myeloid Cell Leukemia Sequence 1 Protein/genetics* ; Humans ; Proto-Oncogene Proteins c-myc/genetics* ; Cell Proliferation ; Signal Transduction ; Neoplasms/pathology* ; F-Box-WD Repeat-Containing Protein 7/genetics* ; Cell Survival ; Cell Line, Tumor ; Apoptosis

Mitochondria are the convergence point of multiple pathways that trigger programmed cell death (PCD). Mitochondrial-associated PCD (mtPCD) is involved in the pathogenesis of several diseases. However, the role of mtPCD in the prognostic prediction of cancers including non-small-cell lung cancer (NSCLC) remains to be investigated. Here, 12 mtPCD patterns were analyzed in transcriptomics, genomics, and clinical data collected from 4 datasets containing 977 patients. A risk-score assessment system containing 18 genes was established. We found that NSCLC patients with a high-risk score had a poorer prognosis. A nomogram was constructed by incorporating the risk score with clinical features. The risk score was further associated with clinicopathological information, tumor-mutation frequency, and immunotherapy responses. NSCLC patients with a high risk score had more Treg cells infiltration. However, these patients had higher tumor-mutation burden scores and may be more sensitive to immunotherapy. Moreover, receptor-interacting serine/threonine protein kinase 2 (RIPK2) was selected from mtPCD gene model for validation. We found that RIPK2 exhibited oncogenic function, and its expression level was inversely associated with the overall survival of NSCLC. Taken together, our results indicated the accuracy and practicability of the mtPCD gene model and RIPK2 in predicting the prognosis of NSCLC.
Humans ; Carcinoma, Non-Small-Cell Lung/pathology* ; Lung Neoplasms/pathology* ; Prognosis ; Male ; Female ; Nomograms ; Middle Aged ; Mitochondria/metabolism* ; Apoptosis/genetics* ; Mutation ; Biomarkers, Tumor/genetics* ; Aged

Ovarian cancer is the most lethal malignancy affecting the female reproductive system. Pharmacological inhibitors targeting CDK4/6 have demonstrated promising efficacy across various cancer types. However, their clinical benefits in ovarian cancer patients fall short of expectations, with only a subset of patients experiencing these advantageous effects. This study aims to provide further clinical and biological evidence for antineoplastic effects of a CDK4/6 inhibitor (TQB4616) in ovarian cancer and explore underlying mechanisms involved. Patient-derived ovarian cancer organoid models were established to evaluate the effectiveness of TQB3616. Potential key genes related to TQB3616 sensitivity were identified through RNA-seq analysis, and TRIM4 was selected as a candidate gene for further investigation. Subsequently, co-immunoprecipitation and GST pull-down assays confirmed that TRIM4 binds to hnRNPDL and promotes its ubiquitination through RING and B-box domains. RIP assay demonstrated that hnRNPDL binded to CDKN2C isoform 2 and suppressed its expression by alternative splicing. Finally, in vivo studies confirmed that the addition of siTRIM4 significantly improved the effectiveness of TQB3616. Overall, our findings suggest that TRIM4 modulates ubiquitin-mediated degradation of hnRNPDL and weakens sensitivity to CDK4/6 inhibitors in ovarian cancer treatment. TRIM4 may serve as a valuable biomarker for predicting sensitivity to CDK4/6 inhibitors in ovarian cancer.
Humans ; Female ; Ovarian Neoplasms/pathology* ; Animals ; Tripartite Motif Proteins/genetics* ; Mice ; Cyclin-Dependent Kinase 4/antagonists & inhibitors* ; Cell Line, Tumor ; Cyclin-Dependent Kinase 6/antagonists & inhibitors* ; Protein Kinase Inhibitors/pharmacology* ; Ubiquitin/metabolism* ; Xenograft Model Antitumor Assays ; Ubiquitination ; Antineoplastic Agents/pharmacology*

OBJECTIVES: Esophageal squamous cell carcinoma (ESCC) is characterized by complex pathogenesis and poor prognosis. In recent years, epithelial-mesenchymal transition (EMT) in tumor initiation and progression has attracted increasing attention. Enhancer of zeste homolog 2 (EZH2), which is aberrantly expressed in various tumors, may be closely related to the EMT process. This study aims to examine the expression and correlation of EZH2 and EMT markers in ESCC cells and tissues, evaluate the effects of EZH2 knockdown on ESCC cell proliferation, invasion, and migration, and explore how EZH2 contributes to the malignant biological behavior of ESCC. METHODS: Bioinformatics analyses were used to assess EZH2 expression levels in ESCC. Small interfering RNA was used to knock down EZH2 in ESCC cell lines EC109 and EC9706. Cell proliferation, invasion, and migration were evaluated using cell counting kit-8 (CCK-8), wound healing, and Transwell assays. Protein and mRNA expression levels of EZH2, E-cadherin (E-cad), and vimentin (Vim) were detected by Western blotting and real time fluorogenic quantitative PCR (RT-qPCR), respectively. Immunohistochemical (IHC) staining was performed on 70 ESCC tissue samples and 40 paired adjacent normal tissues collected from the First Affiliated Hospital of Shihezi University between 2010 and 2016 to assess the expression of EZH2, E-cad, and Vim, and to analyze their associations with clinicopathological feature and patient prognosis. RESULTS: Bioinformatics analysis showed that EZH2 was highly expressed in ESCC (P<0.001), and high EZH2 expression was associated with worse prognosis (P<0.001). CCK-8, wound healing, and Transwell assays demonstrated that EZH2 knockdown significantly suppressed the proliferation, invasion, and migration of ESCC cells (P<0.001). In addition, Vim expression was significantly reduced, while E-cad expression was significantly increased at both protein and mRNA levels in EZH2-silenced cells (all P<0.05). IHC staining analysis revealed higher expression of EZH2 and Vim and lower expression of E-cad in ESCC tissues compared to adjacent normal tissues. Kaplan-Meier survival analysis showed that low expression of EZH2 and Vim and high expression of E-cad were associated with longer survival (all P<0.05). CONCLUSIONS EZH2 promotes malignant biological behavior in ESCC by mediating EMT. Elevated EZH2 expression is associated with poor prognosis in ESCC patients.
Humans ; Enhancer of Zeste Homolog 2 Protein/physiology* ; Esophageal Squamous Cell Carcinoma/pathology* ; Epithelial-Mesenchymal Transition/genetics* ; Esophageal Neoplasms/metabolism* ; Cell Proliferation ; Cell Line, Tumor ; Cell Movement ; Cadherins/genetics* ; Vimentin/genetics* ; Male ; Female ; Middle Aged ; Neoplasm Invasiveness ; Prognosis ; RNA, Small Interfering/genetics* ; Gene Expression Regulation, Neoplastic

BACKGROUND: Lung cancer currently ranks first globally in both incidence and mortality. Pemetrexed (PMX) serves as a first-line treatment for lung adenocarcinoma (LUAD), but the patients often develop drug resistance during therapy. Milk exosome (mEXO) have the advantages of low immunogenicity, high tissue affinity, and low cost, and mEXO itself has anti-tumor effects. Hyaluronan (HA) naturally bind to CD44, a receptor which is highly expressed in LUAD tissues. This study aims to construct hyaluronan-modified milk exosome (HA-mEXO) and preliminarily investigate their molecular mechanisms for reversing PMX resistance through cellular experiments. METHODS: Exosomes were extracted from milk using high-speed centrifugation, and HA-mEXO was constructed. PMX-resistant A549 and PC-9 cell lines were treated with mEXO and HA-mEXO, respectively. CCK-8 assays, colony formation assays, Transwell assays, and flow cytometry were performed to evaluate proliferation, colony formation, migration, invasion, and apoptosis phenotypes in the treated resistant cell lines. Finally, transcriptomic sequencing, analysis, and cellular functional recovery experiments were conducted to investigate the mechanism by which HA-mEXO reverses PMX resistance in LUAD cells. RESULTS: The expression of CD44 in A549 and PC-9 LUAD drug-resistant cell lines was significantly higher than that in parental cells, and the uptake rate of HA-mEXO by drug-resistant cell lines was significantly higher than that of mEXO. Compared to the mEXO group, HA-mEXO-treated A549 and PC-9 resistant cells exhibited significantly reduced half maximal inhibitory concentration (IC50) values for PMX, markedly diminished clonogenic, migratory, and invasive capabilities, and a significantly increased proportion of apoptotic cells. Western blot analysis revealed that, compared to parental cells, A549 and PC-9 drug-resistant cells exhibited downregulated ZNF516 expression and upregulated ABCC5 expression. Immunofluorescence analysis revealed that HA-mEXO treatment downregulated ABCC5 expression in A549 and PC-9 drug-resistant cells compared to the PBS group, whereas co-treatment with HA-mEXO and ZNF516 knockdown showed no significant change in ABCC5 expression. CONCLUSIONS HA-mEXO carrying ZNF516 suppress ABCC5 expression, thereby enhancing the sensitivity of A549 and PC-9 LAUD drug-resistant cells to PMX.
Humans ; Hyaluronic Acid/chemistry* ; Drug Resistance, Neoplasm/drug effects* ; Exosomes/chemistry* ; Adenocarcinoma of Lung/genetics* ; Pemetrexed/pharmacology* ; Animals ; Lung Neoplasms/pathology* ; Milk/chemistry* ; Cell Proliferation/drug effects* ; Apoptosis/drug effects* ; Cell Line, Tumor ; Hyaluronan Receptors/metabolism*