Mitochondrial DNA (mtDNA) haplogroups are associated with various types of cancer; however, the molecular mechanisms by which mtDNA haplogroups affect primary hepatocellular carcinoma (HCC) are not known. In this study, we carried out a case-control study on 388 HCC patients and 511 geographically matched asymptomatic control subjects in northern China. We found that mtDNA haplogroup N9a and its diagnostic SNP, m.16257C > A, negatively correlated with the incidence of HCC in northern China (odds ratio [OR] 0.290, 95% confidence interval [CI] 0.123–0.685, p = 0.005), particularly in patients with infection of hepatitis B/C virus (HBV/HCV) (for haplogroup N9a: OR 0.213, 95% CI 0.077–0.590, p = 0.003; for m.16257C > A: OR 0.262, 95% CI 0.107–0.643, p = 0.003). However, mtDNA haplogroup N9a is not associated with clinical characteristics of HCC including serum alpha-fetoprotein (AFP) level and tumor size. In addition, cytoplasmic hybrid (cybrid) cells with N9a haplogroup (N9a10a and N9a1) had transcriptome profiles distinct from those with non-N9a (B5, D4, and D5) haplogroups. Gene set enrichment analysis (GSEA) showed that metabolic activity varied significantly between N9a and non-N9a haplogroups. Moreover, cells with haplogroup N9a negatively correlated with cell division and multiple liver cancer pathways compared with non-N9a cells. Although it is still unclear how N9a affects the aforementioned GSEA pathways, our data suggest that mtDNA haplogroup N9a is negatively correlated with the incidence and progression of HCC in northern China.

Resistance to apoptosis induced by chemotherapy is still an obstacle for the treatment of chronic myeloid leukemia (CML). Numerous studies have indicated that upregulation of hepatocyte growth factor (HGF) protein expression reduced apoptosis induced by various factors. However, whether HGF has any effect on apoptosis induced by in CML cells and its underlying mechanisms are unclear. HGF was overexpressed in the K562 cell line using transfection. The protein and mRNA expression levels, and the concentration of HGF were measured using western blot analysis, reverse transcription-quantitative (RT-qPCR) and ELISA respectively. Apoptosis in the K562 cell line was determined using flow cytometry and western blot analysis. Changes in cell viability were measured using a MTT assay. RT-qPCR and western blot analysis revealed that HGF was successfully upregulated at both the mRNA and protein expression levels in the K562 cell line, respectively. After VP-16 treatment, the number of apoptotic cells overexpressing HGF was lower compared with that in cells transfected with the empty vector. Mechanistic investigation revealed that overexpression of HGF led to the increase in Bcl-2 protein expression level and inhibition of caspase-3/9 activation. Furthermore, HGF overexpression resulted in activation of the PI3K/Akt signaling pathway. Therefore, the results of the present study revealed that targeting HGF could be used as a strategy to overcome VP-16 resistance in CML.