Chitinase inhibits growth of human breast and colorectal cancer cells in vitro and Ehrlich ascites carcinoma cells in vivo

Abstract

Trichosanthes dioica seed extract was loaded on a QA-cellulose column and the unbound fraction with the chitinase activity was run on SDS-PAGE. Multiple bands were observed and were separated by a Sephadex G-50 column. The combination of the 6 and 33 kDa masses supported the degradation of chitinase as purified earlier. Only the 33 kDa fraction contained sugar and showed chitinase activity. The chitinase was also isolated by using a chitin column. At 200 µg/ml protein concentration, the chitinase inhibited 49.1 %, 48.8 % and 38.12 % of Ehrlich ascites carcinoma, HCT-116 and MCF-7 cells growth, respectively, in a dose-dependent manner. Exactly, 46 % and 82 % EAC cell growth inhibition were observed after treating the EAC cells bearing Swiss albino mice with the chitinase at the doses of 1.0 and 2.0 mg/Kg/day respectively. EAC, HCT-116 and MCF-7 cells growth inhibitions were due to the induction of apoptosis. ROS was accumulated in HCT-116 and MCF-7 cells. After treatment of HCT-116 cells, the expression level of p53 and TNFα genes increased and PARP gene decreased. On the other hand, elevated expression was observed for PARP, MAPK, NFκB, FAS, FADD, and Caspase-8 genes in MCF-7 cells. The induction of apoptosis in HCT-116 was further confirmed by caspase protein expression. The chitinase causes ‘S’ cell cycle arrest in MCF-7 and HCT-116 cells. T. dioica seed chitinase inhibited EAC, HCT-116 and MCF-7 cells by inducing apoptosis in vitro and EAC in vivo in mice. These promising results indicated that T. dioica seed chitinase can be an anticancer agent.

Keywords

• Apoptosis
• Gene expression
• ROS generation
• HCT-116
• MCF-7
• Cell cycle arrest