lncENST Suppress the Warburg Effect Regulating the Tumor Progress by the Nkx2-5/ErbB2 Axis in Hepatocellular Carcinoma

The therapeutic efficacy of radiofrequency ablation (RFA) against liver cancer is often limited by proliferation and metastasis of residual tumor cells. These phenomena are closely associated with the Warburg effect, wherein ErbB2 is activated. While RFA inhibits the Warburg effect of residual tumor cells at the early stage, the specific mechanisms remain unclear. We explored the regulatory relationship between the long noncoding RNA ENST00000570843.1 (lncENST) and ErbB2 using lentiviral transfection of lncENST and ErbB2 overexpression/interference vectors in in vitro and in vivo models of hepatocellular carcinoma in the presence of sublethal heat at 50°C. ErbB2-mediated Warburg effect was suppressed by lncENST, as manifested by reduced glucose uptake and lactic acid production in SMMC-7721 cells. lncENST also increased tumor apoptosis and inhibited tumor progression in nude Balb/c mice for up to 28 days after RFA. Additionally, we predicted through bioinformatic analysis that the promoter of ErbB2 binds to the transcription factor Nkx2-5, resulting in a negative regulatory effect. This speculation was confirmed by chromatin immunoprecipitation of the Nkx2-5 protein and ErbB2, indicating that ErbB2 transcription was curbed by Nkx2-5. We propose that lncENST downplays the Warburg effect in residual tumor cells by downregulating ErbB2 via Nkx2-5 activation. This study is aimed at providing molecular targets that can prevent residual tumor cell proliferation after RFA, with clinical significance in hepatocellular carcinoma treatment.