International Journal of Cancer 2002 Volume 100, Issue S13,
Cytotoxicity and synergistic effect of careseng on cancer cells
W Jia1, H Yan1, P Sun2, E Guns3
1Univ. of B.C., Surgery, Vancouver, B.C., Canada;
2PanaGin Pharmaceuticals, Vancouver, Canada;
3Prostate Research Centre, Vancouver, BC, Canada
The background of the study: Careseng is a natural product containing 4 major ginseng sapogenins, including Rh2 and Protopanaxadiol. In previous studies, these compounds have shown various anti-cancer activity, including G1-phase arrest and induction of apoptosis.
The method used: We have tested the anti-cancer activity of Careseng as well as Rh2 and protopanaxadiol on multi-drug resistant breast cancer cells in cell cultures and animal models. Toxicity of Careseng on animals was also examined.
The results obtained: Our results showed that 48 hours treatment with Careseng caused cell death in both MCF7adr and MDA435/LCC6mdr cell lines with IC50s between 10-20 ug/ml. This cytotoxity was similar to that caused by Rh2 or protopanaxadiol alone. In addition, Rh2 has shown extraordinary synergy with taxol on MDA435/LCC6mdr and its parental non-drug resistant cell line MDA435/LCC6. The drug sensitization effect was more dramatic in drug resistant MDA435/LCC6 cells, where Rh2 reduced IC50 for taxol by 21000-fold at the concentration of 30ug/ml. It was apparent that the cytotoxicity of Careseng or its individual components was not dependent on the levels of estrogen receptors or p53 status. Acute toxicity test on animals showed a transient mild CNS inhibitory effect at the maximum dose (4000 mg/kg). No animal died. Chronic toxicity included a transient hypertrophy in the prostate and ovary at the highest dose (333 mg/kg for 8 weeks).
The conclusion: The above results showed that Careseng is a safe product with a strong potential as a complementary treatment for breast cancer patients.