LncRNA-NEAT1 facilitates autophagy to boost pemetrexed resistance in lung adenocarcinoma via the mir-379-3p/HIF1A pathway.

Background: As a primary chemotherapeutic agent for lung adenocarcinoma (LUAD), pemetrexed (PEM) faces the challenge of resistance development in cancer cells due to its chronic use, which compromises its therapeutic benefits. LncRNA-NEAT1, implicated in the promotion of cancer, is a key player in LUAD. The objective of this study is to explore the contribution of lncRNA-NEAT1 to PEM resistance in LUAD and to dissect the molecular mechanisms involved.

Method: The expression levels of lncRNA-NEAT1 in LUAD tissues and cells were deciphered using the TCGA database and qRT-PCR. To delve into the functional implications of lncRNA-NEAT1, we engineered plasmids to modulate its expression levels in PEM-resistant A549 cells. PEM resistance in the modified cells was then quantitatively assessed via a panel of assays including cell counting kit-8 (CCK-8), and colony formation, and flow cytometry. To predict the interaction sites between lncRNA-NEAT1 and miR-379-3p, along with the miR-379-3p and hypoxia-inducible factor (HIF1A), we referred to the StarBase and TargetScan databases. The interplay between these RNA molecules was further characterized by RNA immunoprecipitation (RIP) and dual-luciferase reporter assays, while the expression of autophagy-related proteins LC3I, LC3II, and Beclin1 was profiled using western blot (WB).

Results: Abundant lncRNA-NEAT1 expression was observed in LUAD tissues and cell lines. Its depletion resulted in impeded growth of A549/PEM cells, enhanced apoptotic rates, and a lowered threshold for PEM to exert a half-maximal inhibitory effect. The interplay between lncRNA-NEAT1 and miR-379-3p, as evidenced by dual-luciferase reporter assays, RIP, and qRT-PCR, led to the upregulation of HIF1A. WB and CCK-8 outcomes illustrated that the autophagy and PEM resistance were compromised when HIF1A expression was curtailed by miR-379-3p mimics in A549/PEM cells. The restoration of these effects was observed upon lncRNA-NEAT1-mediated downregulation of miR-379-3p.

Conclusion: Our study illuminates the role of lncRNA-NEAT1 in LUAD, where it mediates resistance to PEM through the activation of autophagy via the miR-379-3p/HIF1A axis. This work paves the way for new therapeutic strategies for managing PEM resistance in LUAD patients.