Role and mechanism of hexokinase 2 in erlotinib resistance in non-small cell lung cancer

Abstract

Objective To observe the expression of hexokinase 2 (HK2), a key enzyme of glycolysis, in human non-small cell lung cancer (NSCLC) tissues, and to investigate the role and mechanism of HK2 in the resistance of NSCLC to erlotinib. Methods The relationship between the expression of HK2 and prognosis in lung cancer and the effect of erlotinib on NSCLC HK2 gene exlpression were analyzed through online databases (Kaplan-Meier Plotter, GEPIA and GEO DataSets). q-PCR was used to verify the expression differences of HK2 in normal lung epithelial cells and lung cancer cells in vitro. The basic expression of HK2 in erlotinib-sensitive cells (PC9) and erlotinib-resistant cells (PC9/ER) and the expression of HK2 after erlotinib intervention were detected by q-PCR and Western blotting. After 3-bromopyruvate, a HK2 inhibitor, was used to treat PC9/ER cells, the erlotinib resistance and cell proliferation in PC9/ER cells were detected by CCK-8 assay and flow cytometry. Results HK2 was associated with poor prognosis in NSCLC patients, and overall survival (OS) in the group with high expression of HK2 was significantly shortened when compared with the group with low expression (P < 0.05). Cell experiments confirmed that HK2 was relatively highly expressed in PC9/ER cells, and erlotinib treatment could reduce HK2 expression in PC9 cells, but had no significant effect on PC9/ER cells. 3-bromopyruvate successfully inhibited the expression of HK2 in PC9/ER cells. CCK-8 assay showed that IC50 value of erlotinib was significantly lower in the PC9/ER 3-bromopyruvate treated group than the PC9/ER control group (0.005±0.001 vs 1.967±0.436 μmol/L, P=0.016), suggesting that the inhibitor treatment can restore the sensitivity of PC9/ER cells to erlotinib. In addition, the treatment also resulted in significantly decreased proliferation index in the 3-bromopyruvate treatment group than the control group [(14.1±0.8)% vs (30.4±2.3)%, P=0.008), indicating that the inhibitor could significantly inhibit the proliferation of drug-resistant cells. Conclusion HK2 is an indicator for poor prognosis in NSCLC patients. It can induce erlotinib resistance to NSCLC, which may be associated with its promotion in glycolysis, and inhibiting its expression may be an effective strategy to reverse erlotinib resistance in NSCLC.

Keywords

• hexokinase 2
• non-small cell lung cancer
• erlotinib
• cell proliferation