Hypoestoxide inhibits tumor growth in the mouse CT26 colon tumor model

Abstract

Aim: To evaluate the effect of the natural diterpenoid, hypoestoxide (HE) on the growth of established colon cancer in mice. Methods: The CT26.WT mouse colon carcinoma cell line was grown and expanded in vitro. Following the expansion, BALB/c mice were inoculated s.c. with viable tumor cells. After the tumors had established and developed to about 80-90 mm3, the mice were started on chemotherapy by oral administration of HE, 5-fluorouracil (5-FU) or combination. Results: The antiangiogenic HE has previously been shown to inhibit the growth of melanoma in the B16F1 tumor model in C57BL/6 mice. Our results demonstrate that mean volume of tumors in mice treated with oral HE as a single agent or in combination with 5-FU, were significantly smaller (> 60%) than those in vehicle control mice (471.2 mm3 vs 1542.8 mm3, P < 0.01). The significant reductions in tumor burden resulted in pronounced mean survival times (MST) and increased life spans (ILS) in the treated mice. Conclusion: These results indicate that HE is an effective chemotherapeutic agent for colorectal cancer in mice and that HE may be used alone or in combination with 5-FU. © 2007 WJG. All rights reserved.