The presence of metformin also sensitized NSCLC cells to celecoxib-induced apoptosis by activating caspase-9, -8, -3, and -7, upregulating the pro-apoptotic proteins Bad and Bax, and downregulating the antiapoptotic proteins Bcl-xl and Bcl-2. This evidence concerns the gene BCL2L1 and non-small cell lung carcinoma.