Oncotarget
-
SESTRINs (SESN1-3) are proteins encoded by an evolutionarily conserved gene family that plays an important role in the regulation of cell viability and metabolism in response to stress. Many of the effects of SESTRINs are mediated by negative and positive regulation of mechanistic target of rapamycin kinase complexes 1 and 2 (mTORC1 and mTORC2), respectively, that are often deregulated in human cancers where they support cell growth, proliferation, and cell viability. Besides their effects on regulation of mTORC1/2, SESTRINs also control the accumulation of reactive oxygen species, cell death, and mitophagy. ⋯ While we observed that expression of SESN1 and SESN2 is often decreased in human tumors, inactivation of Sesn2 in mice positively regulates tumor growth through a mechanism associated with activation of AKT, while knockout of Sesn1 has no additional impact on carcinogenesis in Sesn2-deficient mice. However, inactivation of SESN1 and/or SESN2 in A549 cells accelerates cell proliferation and imparts resistance to cell death in response to glucose starvation. We propose that despite their contribution to early tumor growth, SESTRINs might suppress late stages of carcinogenesis through inhibition of cell proliferation or activation of cell death in conditions of nutrient deficiency.