Insufficient Radiofrequency Ablation Promotes the Growth of Non-small Cell Lung Cancer Cells Through PI3K/Akt/HIF-1α Signals

Accelerated progression of residual non-small cell lung cancer (NSCLC) after incomplete radiofrequency ablation (RFA) has frequently been reported. In this study, NSCLC cells A549, CCL-185, and H358 were treated using a water bath at 47°C for 5, 10, 15, 20, and 25 min gradually to establish the sublines A549-H, CCL-185-H, and H358-H, respectively. A549-H, CCL-185-H, and H358-H cells showed a significant increase in proliferation rate when compared with their corresponding parental cellsin vitro The expression of hypoxia-inducible factor-1α (HIF-1α) was obviously upregulated in both A549-H and CCL-185-H cells. Silencing of HIF-1α abolished the insufficient RFA-induced proliferation in A549-H and CCL-185-H cells. Furthermore, insufficient RFA treatment markedly elevated the phosphorylation of ERK1/2 and Akt, but not of p38 MAPK or JNK, in A549-H and CCL-185-H cells. The inhibitor of Akt, LY294002, but not the inhibitor of ERK1/2, PD98059, suppressed the upregulation of HIF-1α and the proliferation of A549-H and CCL-185-H cellsin vitro Thein vivoresults confirmed that insufficient RFA could trigger the tumor growth, upregulate the HIF-1α expression, and activate Akt in A549 xenograft tumors. Our data suggest that insufficient RFA can promote thein vitroandin vivogrowth of NSCLC via upregulating HIF-1α through the PI3K/Akt signals.