Inhibition of MDA-MB-231 human breast tumor xenografts and HER2 expressionby anti-tumor agents GAP31 and MAP30

GAP31 (Gelonium protein of 31 kDa) and MAP30 (Momordica protein of 30 kDa) are agents isolated from the medicinal plants Gelonium multiflorum and Momo rdica charantia, respectively. The current study was conducted to investiga te the efficacy of GAP31 and MAP30 on estrogen-independent and highly metas tatic human breast tumor MDA-MB-231 both in vitro and in vivo. The effect o f these agents on the expression of breast tumor antigen HER2 (also known a s neu or as c-erbB 2) was also examined. Treatment of MDA-MB-231 breast can cer cells with GAP31 and MAP30 resulted in inhibition of cancer cell prolif eration as well as inhibition of the expression of HER2 gene in vitro. When MDA-MB-231 human breast cancer cells were transferred into SCID mice, the mice developed extensive metastases and all mice succumbed to tumor by day 46. Treatment of the human breast cancer bearing SCID mice with GAP32 or MA P30 at 10 mu g/injection EOD for 10 injections resulted in significant incr eases in survival, with 20-25% of the mice remaining tumor free for 96 days . Thus antitumor agents GAP31 and MAP30 are effective against human br east cancer MDA-MB-231 in vitro and in vivo. There agents may therefore be of p otential therapeutic use against breast carcinomas.