Gedunin suppresses hepatocellular carcinoma cells growth and metastasis through targeting stem cells population
Introduction
The incidence of hepatocellular carcinoma (HCC) is increasing globally and it is the fourth leading cause of cancer-related mortality around the world. HCC are highly metastatic and have poor prognosis. It is well-known that cancer stem cells play a major role in metastasis. It will be important to target stem cells to develop an effective treatment for HCC. Phytochemical compounds have been known to have anticancer effects in different types of cancer. Gedunin, a phytochemical derived from neem, has demonstrated anti-proliferative and anti-metastatic properties. Here we tested the anti-cancer effect of gedunin on HCC.
Methods
Hep3B, HepG2, and Huh7 liver cancer cell lines and THLE-3 normal liver cells were used to study the effect of gedunin. The cells were treated with different doses of gedunin for 24 hours to determine the IC50 values. ALDH positivity/high-expression was used to sort cancer stem cells. A limiting dilution assay was performed usingHep3B stem cells (100-10,000 cells/flank). The cells were transplanted subcutaneously on both flanks of the athymic nude mice. Once the tumors grew to a size of 100 mm3 they were separated into the following groups: 1) Untreated control, 2) 1mg/kg body weight (bw) gedunin, and 3) 5mg/kg bw gedunin. Each treatment was given twice a week for four weeks. Stem cell pathway array was performed using the treated and untreated xenografts.
Results
Gedunin inhibited cell viability of liver cancer cell lines in a dose-dependent manner. Our results demonstrated that transplanting 5,000 or 10,000 stem cell developed tumors within 3 weeks of transplant, while 100 and 1,000 stem cell transplants took 5 weeks to develop tumors. Both doses of gedunin treatment were effective in inhibiting xenograft tumor growth. Higher dose of 5mg/kg bw dosage was much more effective than 1mg/kg bw dose of gedunin. Stem cell pathway analysis demonstrated that gedunin significantly decreased the expression of pro-stemness markers. On contrast, gedunin inhibited mesenchymal markers.
Conclusion
Gedunin could be a potential therapeutic option for HCC, which is expected to be highly effective in inhibiting metastasis as it targets both cancer bulk cells and cancer stem cells.