A nutrient mixture reduced tumor growth of SK-UT-1 human leiomyosarcoma cells in vivo and in vitro by inhibiting MMPs and inducing apoptosis.

Abstract

Uterine leiomyosarcoma is a rare malignant smooth muscle tumor originating in the uterine wall that generally responds poorly to chemotherapy and radiation. We investigated the in vitro effects of a novel nutrient mixture containing lysine, proline, ascorbic acid, and green tea extract on the human leiomyosarcoma cell line SK-UT-1by measuring cell proliferation, invasiveness, apoptosis, and expression of matrix metalloproteinases (MMP). We also tested the effects of nutrient mixture in vivo using nude mice. Human leiomyosarcoma SK-UT-1cells were treated with different concentrations of nutrient mixture. Cell proliferation was determined by MTT assay; MMP expression by gelatinase zymography; invasion by Matrigel assay; migration by scratch test; apoptosis using Live Green caspase kit. In vivo studies were conducted on 5-6weeks old female nude mice inoculated subcutaneously with 3• 106SK-UT-1cells. The mice were fed a regular diet or a diet supplemented with 0.5% nutrient mixture. After four weeks, the mice were sacrificed and the tumors were weighed and processed for histology. In vitro, nutrient mixture treatment was not toxic to SK-UT-1cells at 250µg/ml but exhibited 20% and 40% cytotoxicity at 500and 1000µg/ml respectively. Zymography did not show bands for either MMP-2or MMP-9in SK-UT-1cells. However, treatment with phorbol myristate acetate stimulated the expression of MMP-9, both active and inactive forms in equal proportion. Nutrient mixture inhibited the secretion of both active and inactive forms in a dose dependent manner. Invasion through Matrigel and migration by scratch test were inhibited in a dose dependent fashion, with both invasion and migration inhibited at 250µg/ml. Live Green Caspase apoptosis assay demonstrated slight apoptosis at 100µg/ml and significant apoptosis at 250to 1000µg/ml. The results of in vitro studies were further confirmed in vivo by showing 50% decrease in tumor weight, 40% reduction in tumor burden compared to the tumors from mice fed regular diet. The results suggest a therapeutic potential for nutrient mixture in uterine leiomyosarcoma treatment.