PI3K/AKT/mTOR pathway

About: PI3K/AKT/mTOR pathway is a research topic. Over the lifetime, 51207 publications have been published within this topic receiving 2130942 citations. The topic is also known as: PI3K/AKT/TOR pathway.

Choline Transporters in Human Lung Adenocarcinoma: Expression and Functional Implications

Abstract: Choline is an essential nutrient for cell survival and proliferation, however, the expression and function of choline transporters have not been well identified in cancer. In this study, we detected the mRNA and protein expression of organic cation transporter OCT3, carnitine/cation transporters OCTN1 and OCTN2, and choline transporter-like protein CTL1 in human lung adenocarcinoma cell lines A549, H1299 and SPC-A-1. Their expression pattern was further confirmed in 25 human primary adenocarcinoma tissues. The choline uptake in these cell lines was significantly blocked by CTL1 inhibitor, but only partially inhibited by OCT or OCTN inhibitors. The efficacy of these inhibitors on cell proliferation is closely correlated with their abilities to block choline transport. Under the native expression of these transporters, the total choline uptake was notably blocked by specific PI3K/AKT inhibitors. These results describe the expression of choline transporters and their relevant function in cell proliferation of human lung adenocarcinoma, thus providing a potential "choline-starvation" strategy of cancer interference through targeting choline transporters, especially CTL1.

Cyclic AMP Controls mTOR through Regulation of the Dynamic Interaction between Rheb and Phosphodiesterase 4D

Abstract: The mammalian target of rapamycin complex 1 (mTORC1) is a molecular hub that regulates protein synthesis in response to a number of extracellular stimuli. Cyclic AMP (cAMP) is considered to be an important second messenger that controls mTOR; however, the signaling components of this pathway have not yet been elucidated. Here, we identify cAMP phosphodiesterase 4D (PDE4D) as a binding partner of Rheb that acts as a cAMP-specific negative regulator of mTORC1. Under basal conditions, PDE4D binds Rheb in a noncatalytic manner that does not require its cAMP-hydrolyzing activity and thereby inhibits the ability of Rheb to activate mTORC1. However, elevated cAMP levels disrupt the interaction of PDE4D with Rheb and increase the interaction between Rheb and mTOR. This enhanced Rheb-mTOR interaction induces the activation of mTORC1 and cap-dependent translation, a cellular function of mTORC1. Taken together, our results suggest a novel regulatory mechanism for mTORC1 in which the cAMP-determined dynamic interaction between Rheb and PDE4D provides a key, unique regulatory event. We also propose a new role for PDE4 as a molecular transducer for cAMP signaling.

Advanced glycation end product (AGE)-induced proliferation of HEL cells via receptor for AGE-related signal pathways.

Abstract: This study investigated whether advanced glycation end products (AGE) and RAGE (receptor for AGE) are involved in the proliferation of leukemia cells. AGE strongly induced the proliferation of primary acute myeloid leukemia (AML) cells and cell lines. MAP kinase, PI3K and JAK/STAT pathways were involved in cellular proliferation of HEL cells by AGE. RAGE antisense S-ODN effectively inhibited cell growth, induced apoptosis and reversed AGE-induced expression of targeting molecules in HEL cells. The study demonstrated for the first time that AGE directly induced human AML cell proliferation via the MAPK, PI3K and JAK/STAT pathways.