Functional changes in murine mammary cancer cells elicited by CoCl2-induced hypoxia

Low O2 levels in solid tumors are associated with increase in hypoxia-inducible factor 1α (HIF-1α). The present study examines functional changes involved in adaptation to hypoxia of the LMM3 mammary tumor cell line, using CoCl2 as hypoxic mimetic. Our results showed that LMM3 cells were not only tolerant to 150 μM CoCl2 but they can overgrowth in vitro respect to untreated cells. Hypoxia inhibited cell invasion, migration, MMP-9 activity and NO levels. Macrophage cytotoxicity augmented under hypoxia but was blunted by conditioned media from tumor cells. In vivo tumorigenicity of CoCl2-treated cells was greater than controls. Our results show stabilization of HIF-1α in LMM3 cells under CoCl2 and functional changes associated with enhanced cell survival and growth but not with tumor dissemination.