Long noncoding RNAs (lncRNAs) have recently received wide attention as key molecules that mediate a variety of physiological and pathological processes by regulating gene expression; however, knowledge of lncRNAs in rheumatoid arthritis (RA) is limited. Thus, we investigated the lncRNA expression profile in fibroblast-like synoviocytes (FLSs) from patients with RA and explored the function of abundantly expressed lncRNAs. LncRNA and mRNA microarrays were performed to identify differentially expressed lncRNAs in RA FLSs compared with normal FLSs. Quantitative polymerase chain reaction (qPCR) was used to validate the results, and correlation analysis was used to analyze the relationship between these aberrantly expressed lncRNAs and clinical characteristics. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of the lncRNAs identified. According to the gene expression profiles, 135 lncRNAs were differentially expressed between RA and normal FLSs. Furthermore, qPCR data showed that lncRNA ENST00000483588 was up-regulated and that three lncRNAs (ENST00000438399, uc004afb.1, and ENST00000452247) were down-regulated in RA FLSs. The expression level of ENST00000483588 was positively correlated with the level of C-reactive protein and the Simplified Disease Activity Index score. Moreover, the areas under the ROC curve were 0.85, 0.92, 0.97, and 0.92 for ENST00000483588, ENST00000438399, uc004afb.1, and ENST00000452247, respectively. The results indicate that the dysregulation of ENST00000483588, ENST00000438399, uc004afb.1, and ENST00000452247 may be involved in the pathological processes of RA and that these lncRNAs may have potential value for the diagnosis and assessment of the disease activity of RA.

Almonertinib is the initial third-generation EGFR-TKI in China, but its resistance mechanism is unknown. Cancer-associated fibroblasts (CAFs) are essential matrix components in the tumor microenvironment, but their impact on almonertinib resistance is unknown. This study aimed to explore the correlation between CAFs and almonertinib resistance in non-small cell lung cancer (NSCLC). The anti-cancer effects of almonertinib on NSCLC cells, as well as the reversal of these effects mediated by CAFs, were validated through phenotypic experiments. Differential gene expression analysis, along with GO and KEGG enrichment analyses, was performed to predict the potential mechanisms underlying resistance to third-generation EGFR-TKIs. Finally, qPCR and Western blot analyses were used to explore the signaling pathways by which CAFs induce resistance to almonertinib in NSCLC cells. Our findings revealed that almonertinib significantly suppressed the invasion, migration, and proliferation of EGFR T790M-mutant NSCLC cells. TGF-β1 successfully induced the differentiation of CAFs and upregulated the expression of CAF markers, including α-SMA and fibroblast activation protein (FAP). Exposure of H1975 cells to almonertinib increased TGF-β1 secretion. Additionally, CAFs enhanced the survival of almonertinib-treated NSCLC cells, whereas normal fibroblasts (NFs) exerted the opposite effect. qPCR analysis demonstrated that the expression of the core molecules of the Hippo pathway, YAP and TAZ, was lower in A549 cells than in H1975 cells, and CAF intervention further reduced YAP/TAZ expression in H1975 cells. Western blot analysis confirmed a significant reduction in YAP/TAZ protein levels in cancer cells treated with CAF-conditioned medium (CAF-CM) compared to those treated with normal control-conditioned medium (NC-CM). Finally, we demonstrated that CAFs induced resistance to almonertinib in NSCLC cells, potentially through a mechanism involving YAP/TAZ. This study demonstrated that H1975 cells stimulated by almonertinib promoted the accumulation of CAFs in NSCLC cells, likely through increased secretion of TGF-β1. The accumulation of CAFs enhanced the survival of NSCLC cells undergoing almonertinib treatment and induced drug resistance. Additionally, the mechanism underlying CAF-induced drug resistance in NSCLC cells was potentially linked to the activation of the YAP/TAZ signaling pathway.

Background: The methylation of adenosines at the N6 position (N6-methyladenosine; m6A) is one of the most conserved internal RNA modifications. m6A can modulate the expression of oncogenes or tumor suppressor genes, as well as m6A levels and the expression and activity of m6A enzymes, thus influencing tumor progression and therapeutic response. This study investigates the role of YTHDC2-mediated m6A messenger RNA (mRNA) modification of Id3 in controlling cisplatin resistance in non-small cell lung cancer (NSCLC). Methods: The expression of the m6A reader protein YTHDC2 was detected in an NSCLC cisplatin-resistant cell line (A549/DDP) using real-time fluorescence quantitative polymerase chain reaction (qPCR). YTHDC2 overexpression plasmids were constructed and transfected into A549/DDP and A549 cells respectively. We performed qPCR and western blot (WB) to detect changes in YTHDC2 and Id3 expression, and the effects of YTHDC2 overexpression on proliferation, apoptosis, invasion, and migration of drug-resistant cells were assessed by cell counting kit-8 (CCK-8), flow cytometry, and transwell and scratch assays. The m6A modification of Id3 by YTHDC2 was clarified by m6A-immunoprecipitation-PCR (m6A-IP-PCR) assay. Results: The CLIPdb online database predicted that YTHDC2 might bind to Id3. The results of qPCR showed that YTHDC2 was downregulated in the NSCLC cisplatin-resistant cell line A549/DDP compared to the cisplatin-sensitive cell line A549. Overexpression of YTHDC2 increased the expression of Id3, and the methylation inhibitor 3-deazaadenosine abrogated the regulatory effect of YTHDC2 on Id3. YTHDC2 overexpression significantly inhibited A549/DDP cell proliferation, migration, and invasion, and promoted apoptosis by synergistically promoting the effects of Id3. m6A-IP-PCR analysis revealed that YTHDC2 could inhibit the m6A level of Id3 mRNA. Conclusions: To regulate the activity of Id3, YTHDC2 requires modifications to m6A, which ultimately inhibit cisplatin resistance in NSCLC.

Background Almonertinib is a third-generation EGFR-TKI, and studies on its resistance mechanisms are lacking. Cancer-associated fibroblasts (CAFs) can influence resistance to targeted therapeutics, but their role and mechanism of action in relation to almonertinib resistance are unclear. The study explored relationships among glycolysis, cancer-associated fibroblasts (CAFs), and almonertinib resistance. Methods A dose-escalation method was used to develop the almonertinib-resistant cell line H1975AR. Hexokinase 2 (HK2) effects on almonertinib resistance were evaluated using Cell Counting Kit-8 assays, transcriptome sequencing, western blotting, real-time PCR, siRNA assays, glucose consumption, and lactate production assays. Differential gene expression analysis and siRNA assays in H1975 cells cultured with CAF-conditioned medium (H1975/CAF-CM) revealed S-phase kinase-associated protein 2 (SKP2) as a target driving the effects of HK2. The impact of almonertinib and HK2 inhibitors on H1975/CAF-CM cells was assessed using colony formation, wound healing, transwell, and flow cytometry apoptosis assays. Results H1975AR cells displayed elevated glycolysis and HK2. Subsequently, we showed that knockdown reduced almonertinib resistance in cells. H1975/CAF-CM induced almonertinib resistance and upregulation of HK2, which was reversed by knockdown of SKP2. CAFs regulate HK2-mediated glycolysis through SKP2, promoting almonertinib resistance in NSCLC. Conclusions CAFs regulate HK2-mediated glycolysis through SKP2, which promotes almonertinib resistance in NSCLC.

Background and Aims: Epoxide hydrolase 2 (EPHX2) regulates lipid signaling across various metabolites by encoding soluble epoxide hydrolase. However, its mechanisms and implications in human malignancies remain unknown. This research aimed to detail the prognostic landscape of EPHX2 in pan‐cancer and explore its potential relationship with immune infiltration in the tumor microenvironment.Methods: Herein, multiple bioinformatics tools were used to comprehensively evaluate the expression, diagnostic, and prognostic significance of EPHX2 and its roles in the tumor immune microenvironment in human cancers. The underlying EPHX2‐associated signaling pathways in cancers were investigated by gene set variation analysis (GSVA). TIDE, GDSC, and CTRP databases were applied to predict the response of EPHX2 to immunotherapy and sensitivity to small molecule drugs. Furthermore, EPHX2 expression was also validated by qPCR experiments in various cancer cell lines.Results: Overall results revealed significant down‐regulation of EPHX2 mRNA expression in most tumors. Despite its high predictive significance across cancers, EPHX2 played a protective or detrimental effect in distinct types of cancers. EPHX2 proved to be a valuable diagnostic biomarker in a range of tumor types, particularly in kidney renal clear cell carcinoma, cervical squamous cell carcinoma, and endocervical adenocarcinoma. Genetic alterations of EPHX2 in 33 tumors were also investigated. EPHX2 expression was significantly linked to immune cell infiltrations (particularly tumor‐associated macrophages), tumor mutation burden, microsatellite instability, immune modulators, and immunotherapeutic biomarkers. Single‐cell sequencing and GSVA highlighted the relevance of EPHX2 in regulating various cancer‐related biological processes, including cell cycle and apoptosis. In this view, targeting EPHX2‐dependent signaling could be a promising therapeutic strategy for tumor immunotherapy.Conclusion: EPHX2 may serve as a potential molecular biomarker for diagnosis and prognosis in pan‐cancer and could become a novel therapeutic target for various cancers.

Lung cancer is a leading cause of cancer deaths worldwide, underscoring the need for new biomarkers. Circular RNAs (circRNAs) exhibit potential as biomarkers for lung cancer. ZBTB46 is linked to lung cancer prognosis. This study intends to investigate circRNA expression and the role of ZBTB46 in predicting and treating lung cancer. CircRNAs demonstrate differential expression in lung cancer and paracarcinoma tissues, as identified by high-throughput sequencing (RNA-seq). DEcircRNAs were analyzed through GO and KEGG analyses. A potential circRNA-miRNA-mRNA axis was predicted based on ceRNA theory. ZBTB46 expression in lung cancer tissue was compared to normal tissue. Using the TCGA database, protein expression was compared through the CPTAC and HPA databases. We identified 411 differentially expressed circRNAs, of which 365 were down-regulated and 46 were up-regulated. By combining qRT-PCR validation results, ceRNA theory, and intersecting data from several databases, hsa_circ_0002872/hsa-miR-29b-1-5p/ZBTB46 was predicted as the most promising downstream regulatory axis. ZBTB46 mRNA and protein expression were reduced in human lung cancer tissue compared to normal tissue. hsa_circ_0002872/hsa-miR-29b-1-5p/ZBTB46 represents an axis that may influence lung cancer progression, with the molecule ZBTB46 potentially inhibiting lung cancer progression and serving as a useful prognostic indicator.