ABSTRACT
The established recognition of N6-methyladenosine (m6A) modification as an indispensable regulatory agent in human cancer is widely accepted. However, the understanding of m6A's role and the mechanisms underlying its contribution to gefitinib resistance is notably limited. Herein, using RT-qPCR, Western blot, Cell proliferation and apoptosis, as well as RNA m6A modification assays, we substantiated that heightened FTO (Fat Mass and Obesity-associated protein) expression substantially underpins the emergence of gefitinib resistance in NSCLC cells. This FTO-driven gefitinib resistance is hinged upon the co-occurrence of PELI3 (Pellino E3 Ubiquitin Protein Ligase Family Member 3) expression and concurrent autophagy activation. Manipulation of PELI3 expression and autophagy activation, including its attenuation, was efficacious in both inducing and overcoming gefitinib resistance within NSCLC cells, as validated in vitro and in vivo. In summary, this study has successfully elucidated the intricate interplay involving FTO-mediated m6A modification, its consequential downstream effect on PELI3, and the concurrent involvement of autophagy in fostering the emergence of gefitinib resistance within the therapeutic context of NSCLC.
ABSTRACT
Background: Long noncoding RNAs (lncRNAs) are emerging as key players in the development and progression of cancer. Several malignancies involve dysregulated long noncoding ribonucleic acids (lncRNAs) in non-small cell lung cancer cell growth and their aggressive phenotypes. LncRNA B4GALT1-AS1 is important in the advancement of various malignancies, although its contribution to non-small cell lung cancer (NSCLC) remains unexplored. Methods: LncRNA B4GALT1-AS1 in NSCLC tissues was detected and further validated in a cohort of non-small cell lung cancer tissues. The effects of lncRNA B4GALT1-AS1 on proliferation were determined by in vitro experiments. The B4GALT1-AS1-miR-144-3p-ZEB1 axis was assessed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Furthermore, the mechanism of B4GALT1-AS1 was investigated using loss-of-function assays in vitro. Results: We showed significant upregulation of B4GALT1-AS1 in cell lines and tissues of NSCLC. B4GALT1-AS1 knockdown impeded the in vitro proliferation-related characteristics of the NSCLC cells. The demonstration of the binding capacity of B4GALT1-AS1 and miR-144-3p was predicted by bioinformatics and luciferase reporter activity assay. The B4GALT1-AS1 and miR-144-3p interaction was shown by using rescue experiments. NSCLC has a positive association with its target, zinc finger e-box binding homeobox 1 (ZEB1). Conclusions: In summary, the progression of NSCLC was facilitated by lncRNA B4GALT1-AS1 via interaction with miR-144-3p and positive regulation of ZEB1 expression.
ABSTRACT
Drug resistance is a critical factor responsible for the recurrence of non-small cell lung cancer (NSCLC). Previous studies suggest that curcumin acts as a chemosensitizer and radiosensitizer in human malignancies, but the underlying mechanism remains elusive. In the present study, we explored how curcumin regulates the expression of miR-142-5p and sensitizes NSCLC cells to crizotinib. We found that miR-142-5p is significantly downregulated in NSCLC tissue samples and cell lines. Curcumin could increase crizotinib cytotoxicity by epigenetically restoring the expression of miR-142-5p. Furthermore, curcumin treatment suppressed the expression of DNA methylation-related enzymes, including DNMT1, DNMT3A, and DNMT3B, in NSCLC cells. In addition, the upregulation of miR-142-5p expression increased crizotinib cytotoxicity and induced apoptosis in tumor cells in a similar manner to that of curcumin. Strikingly, miR-142-5p overexpression suppressed crizotinib-induced autophagy in A549 and H460 cells. Mechanistically, miR-142-5p inhibited autophagy in lung cancer cells by targeting Ulk1. Overexpression of Ulk1 abrogated the miR-142-5p-induced elevation of crizotinib cytotoxicity in A549 and H460 cells. Collectively, our findings demonstrate that curcumin sensitizes NSCLC cells to crizotinib by inactivating autophagy through the regulation of miR-142-5p and its target Ulk1.