We also observed a significantly higher COL3A1 expression in H460/DDP cells than in its lung cancer non-resistant H460 cells, suggesting that COL3A1 regulated lung cancer sensitivity to DDP. As expected, silencing COL3A1 increased the sensitivity of A549/ DDP and H1299/DDP to DDP, confirming that increased COL3A1 expression made the cancer cells more prone to DDP resistance.