Low Dose of 5-Aminolevulinic Acid Hydrochloride Alleviates the Damage in Cardiomyocytes Induced by Lenvatinib via PI3K/AKT Signaling Pathway

Lenvatinib is an oral tyrosine kinase inhibitor (TKI), and has been applied in the clinical trials for the treatment of hepatocellular carcinoma (HCC). The function of 5-aminolevulinic acid hydrochloride (ALA) treatment in protecting cardiomyocytes under lenvatinib stimulation was investigated.H9c2 cells were treated with 2 mg/mL lenvatinib for 48 h and 1 mM ALA in the lenvatinib with low dose 5-aminolevulinic acid treatment group (LL) group, 10 mM ALA in the lenvatinib with high-dose 5-aminolevulinic acid treatment group (LH) group and cells without treatment were used as an internal control. C57/BL mice were treated with 10 mg/kg lenvatinib and 200 mg/kg ALA in the LL group and 400 mg/kg ALA in the LH group by gavage once per day for 4 weeks. The proliferation ability of cells was detected using the methyl thiazolyl tetrazolium (MTT) assay. Target gene expression was calculated through real-time quantitative PCR (qPCR), and target protein expression was calculated through Western blotting analysis. The concentrations of cardiovascular protective factors were detected using enzyme linked immunosorbent assay (ELISA).In these experiments, 10 mM ALA significantly increased the viability rate of cardiomyocytes (105.4 ± 8.0%) compared with the single lenvatinib treatment group (73.2 ± 6.5%). We also noticed that activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways were activated after low-dose ALA treatment. 5-ALA treatment led to the downregulation of intercellular cell adhesion molecule-1 (ICAM-1) (0.81- and 0.71-fold), vascular cell adhesion molecule (VCAM) (0.63- and 0.66-fold), angiotensin I (ANGI) (0.88- and 0.66-fold), ANGII (0.66- and 0.48-fold) and upregulation of endothelial nitric oxide synthases (eNOS) (1.25- and 1.89-fold) compared with non 5-ALA treatment group.With more experiments on animal models, low-dose of ALA treatment might be a therapeutic strategy to alleviate the damage to cardiomyocytes induced by lenvatinib.