Dual functions of autophagy in the response of breast tumor cells to radiation: cytoprotective autophagy with radiation alone and cytotoxic autophagy in radiosensitization by vitamin D 3.

ABSTRACT: In MCF-7 breast tumor cells, ionizing radiation promoted autophagy that was cytoprotective; pharmacological or genetic interference with autophagy induced by radiation resulted in growth suppression and/or cell killing (primarily by apoptosis). The hormonally active form of vitamin D, 1,25D 3, also promoted autophagy in irradiated MCF-7 cells, sensitized the cells to radiation and suppressed the proliferative recovery that occurs after radiation alone. 1,25D 3 enhanced radiosensitivity and promoted autophagy in MCF-7 cells that overexpress Her-2/neu as well as in p53 mutant Hs578t breast tumor cells. In contrast, 1,25D 3 failed to alter radiosensitivity or promote autophagy in the BT474 breast tumor cell line with low-level expression of the vitamin D receptor. Enhancement of MCF-7 cell se

SUBMITTER: Bristol ML 

PROVIDER: S-EPMC3378418 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature