Background: Collagen type III alpha 1 chain (COL3A1) is reported to mediate drug resistance in various cancers, and public database analysis indicated its overexpression in lung cancer. Aims: To investigate the effects of COL3A1 on modulating cisplatin (DDP) resistance in lung carcinoma. Study Design: A cell study. Methods: Gene Expression Omnibus datasets were used to determine the differentially expressed genes between H460 and H460/DDP cell lines using bioinformatics analysis. COL3A1 expression and its clinical value in lung cancer prognosis were analyzed using GEPIA and UALCAN databases. Its roles in modulating the growth, viability, apoptosis, and drug resistance were also assessed in vitro. Results: In H460/DDP cells, the CLO3A1 was among the up-regulated genes compared to H460 cells.COL3A1 overexpression and its association with poor survival in patients with adenocarcinoma were detected by public database analysis. In A549 and H1299 cells, COL3A1 overexpression was associated with increased cell growth and clone formation but decreased cell apoptosis, whereas its reduced expression led to decreased cell growth and clone formation and increased cell apoptosis. Conclusion: COL3A1 is upregulated in lung cancer cells with DDP resistance, and its downregulation sensitizes the cells to DDP.

Purpose: To investigate the role of nuclear protein 1 (NUPR1) in the drug resistance of non-small cell lung cancer (NSCLC) and its regulatory mechanisms. Methods: Quantitative polymerase chain reaction (qPCR) and immunoblot assays were conducted to determine NUPR1 expression in A549 cells. Cisplatin sensitivity and cisplatin-induced apoptosis were investigated in NUPR1 knockdown or overexpressed cells via 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay and flow cytometry. The potential association between unfolded protein response (UPR) and NUPR1 levels in response to cisplatin were explored. The effect of endoplasmic reticulum (ER) stress on apoptosis was examined using flow cytometry. Results: Cisplatin treatment promoted the expression of NUPR1 in NSCLC cells. NUPR1 regulated cisplatin resistance in NSCLC and also regulated UPR in ER stress induced by cisplatin. The results show NUPR1 regulated apoptosis induced by ER stress following tunicamycin treatment. Conclusion: NSCLC cells may promote the UPR in ER stress by promoting the expression of NUPR1, thereby reducing the ER stress induced by cisplatin.