Synergy between vinorelbine and afatinib in the inhibition of non-small cell lung cancer progression by EGFR and p53 signaling pathways

Currently, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) were approved for the treatment of non-small cell lung cancer (NSCLC) patients harboring EGFR mutation. However, some lung cancer patients fail to respond and eventually develop drug resistance. Therefore, new therapeutic strategies are needed to improve the outcomes for substantial clinical benefit. Here we aimed to explore the combination of vinorelbine with the second EGFR-TKI afatinib in NSCLC cells with or without EGFR mutation. The three cells of H1975, HCC827, and H460 were assessed for the combination of vinorelbine and afatinib. Vinorelbine combined with afatinib synergistically inhibited the three lung cancer cells growth without aggravating adverse effect on the normal lung cells. The combination of low doses of vinorelbine and afatinib suppressed the cancer cell proliferation by cell colony formation assay and significantly induced cell apoptosis. The anti-apoptotic proteins Bcl-xL and Bcl-2 showed significant reduction after the drug combination treatment, while the pro-apoptotic protein Bax as well as apoptosis indicators cytochrome C and cleaved PARP were observed a notable increasing. EGFR downstream pathways including AKT, ERK, JNK, and p38 were highly active and p53 was inactive in the three lung cancer cells, favoring tumor growth. The low doses of vinorelbine plus afatinib blocked the phosphorylation of AKT, ERK, JNK, and p38, but restored the expression of p53. Our findings suggested that the combination of vinorelbine and afatinib could be recommended as a therapeutic regimen for treatment of NSCLC with or without EGFR mutation.