ABSTRACT
Objective: To evaluate the radiosensitizing potential of Derris scandens extract in a human colon cancer cell model. Methods: The radiosensitizing effect of D., scandens extract on human colon cancer cells (HT-29) and non-cancerous human retinal epithelial cells (RPE) was determined by cell survival and micronuclei analysis after irradiation. Cell cycle distribution was analyzed by a flow cytometer. Results: D. scandens extract powerfully increases the radiosensitivity of HT-29 cells, but is less toxic and does not affect the radiosensitivity of RPE cells. Furthermore, the extract was found to reduce radiation-induced G2/M phase arrest in HT-29 cells, but not in RPE cells. Conclusion: D., scandens extract may have potential as a radiosensitizer for cancer treatment.
ABSTRACT
Insulin like growth factor 1 signalling is a potent biological regulator for the growth and development in mammals. It controls tissue homeostasis throughout life via regulation of cell proliferation and apoptosis. Increased insulin like growth factor 1 signalling stimulates proliferation, promotes metastasis, and causes radio-resistance of cancer cells whereas decreased IGF-1 signalling is associated with increased incidence of cancer and enhanced cellular radio-sensitivity. The important role of Insulin like growth factor 1 signalling as a pro-survival factor and its potential as a modifier of cellular radiosensitivity motivated research in the area of radiation oncology. Therefore this paper will review recent literatures on the insulin like growth factor 1 system and its role in cell survival and cellular response to radiation. The connection of IGF-1 signalling to classical pro-survival and anti-apoptotic signaling cascades will be reviewed.