Reviews
CHEN Yin-Tao, YU Bing-Zhi, WU Di-Di
Chinese Journal of Biochemistry and Molecular Biol.
2014, 30(10):
949-956.
The mammalian target of rapamycin (mTOR) and Akt/PKB (protein kinase B) are closely related to cancers. As a downstream effector and regulator of PI3K, the mTOR molecule regulates mRNA translation, metabolism and autophagy to affect cell growth. There are two types of mTOR multi protein complexes: mTORC1 and mTORC2. The former is sensitive to rapamycin and acts to respond to four major regulatory stimulations of nutrients, growth factors, energy and stress. The growth factor/PI3K/Akt pathway is the most identified signaling pathway for which to regulate. The latter is characterized as a kinase to phosphorylate Akt at Ser473, and then regulate cell growth/proliferation, motility, survival, and differentiation, especially when coordinated with Thr308 of Akt. The PI3K/Akt/mTOR pathway is an important therapeutic target of cancer treatments for its critical role in cancer cells. However, the first generation mTORC1-specific inhibitors of rapamycin analogs showed limited efficacy, probably due to the feedback activation of upstream PI3K signaling. Recently, the second generation inhibitors acted on both of mTORC1/2 and PI3K, which can be more promising in cancer treatment. This review describes recent reports on such novel inhibitors and their functions in the PI3K/Akt/mTOR signaling pathway.