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

Background: 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.

Methods: 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).

Results: 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.

Conclusions: 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.