Hepatocellular carcinoma (HCC) is the third most lethal
cancer worldwide. Despite progress in identifying risk factors, the incidence of HCC is increasing. Moreover, therapeutic options are limited and survival is poor. Therefore, alternative and innovative therapeutic strategies are urgently required. R-Tf-D-LP4, a
cell-penetrating peptide derived from the mitochondrial multifunctional
protein the
voltage-dependent anion channel (VDAC1), is identified here as a highly effective
liver cancer treatment. Recently, we demonstrated that R-Tf-D-LP4 induced apoptosis and inhibited
tumor growth in mouse models. We now demonstrate that R-Tf-D-LP4 induced apoptosis in
cancer liver-derived cell lines and inhibited
tumor growth in three different
liver cancer mouse models. These included
diethylnitrosamine (DEN)-induced HCC, metabolically high-fat diet-induced HCC, and using a subcutaneous HepG2 cell xenograft model.
Intravenous injection of the
peptide into
tumor-carrying DEN-treated mice resulted in dose-dependent inhibition of
tumor growth up to complete
tumor elimination. TUNEL staining of liver sections demonstrated
peptide-induced apoptosis.
Hematoxylin/
eosin and Sirius red staining of liver sections showed decreased fibrotic formation. Immunohistochemical staining demonstrated reduced numbers of α-SMA-expressing cells in R-Tf-D-LP4-treated mouse livers. Additionally, macrophage presence in liver tissue was reduced in R-Tf-D-LP4-treated mice. Liver sections from DEN-treated mice showed steatohepatic pathology, reflected as
fatty liver,
inflammation, ballooning degeneration, and
fibrosis; all were eliminated upon
peptide treatment.
Peptide treatment also inhibited
tumor development in a
nonalcoholic steatohepatitis-
hepatocellular carcinoma mouse model induced by HFD. In HepG2 subcutaneous
tumor xenografts, R-Tf-D-LP4 inhibited
tumor growth.
CONCLUSION: These results show that the VDAC1-based
peptide R-Tf-D-LP4 has multiple effects on
liver cancer cells, leading to impairment of cell energy and metabolism homeostasis, induction of apoptosis, and elimination of
liver cancer-associated processes, and thus represents a promising therapeutic approach for
liver cancer.