10.1371/journal.pone.0114573 Ming Ming Ming Ming James Sinnett-Smith James Sinnett-Smith Jia Wang Jia Wang Heloisa P. Soares Heloisa P. Soares Steven H. Young Steven H. Young Guido Eibl Guido Eibl Enrique Rozengurt Enrique Rozengurt Dose-Dependent AMPK-Dependent and Independent Mechanisms of Berberine and Metformin Inhibition of mTORC1, ERK, DNA Synthesis and Proliferation in Pancreatic Cancer Cells Public Library of Science 2014 pancreatic ductal adenocarcinoma intracellular ATP levels mTORC 1 AMPK α subunit acc PDAC cells Pancreatic Cancer Cells Natural products 6k G 1. Berberine treatment berberine erk DNA synthesis PANC 2014-12-10 14:42:07 Dataset https://plos.figshare.com/articles/dataset/_Dose_Dependent_AMPK_Dependent_and_Independent_Mechanisms_of_Berberine_and_Metformin_Inhibition_of_mTORC1_ERK_DNA_Synthesis_and_Proliferation_in_Pancreatic_Cancer_Cells_/1267493 <div><p>Natural products represent a rich reservoir of potential small chemical molecules exhibiting anti-proliferative and chemopreventive properties. Here, we show that treatment of pancreatic ductal adenocarcinoma (PDAC) cells (PANC-1, MiaPaCa-2) with the isoquinoline alkaloid berberine (0.3–6 µM) inhibited DNA synthesis and proliferation of these cells and delay the progression of their cell cycle in G1. Berberine treatment also reduced (by 70%) the growth of MiaPaCa-2 cell growth when implanted into the flanks of nu/nu mice. Mechanistic studies revealed that berberine decreased mitochondrial membrane potential and intracellular ATP levels and induced potent AMPK activation, as shown by phosphorylation of AMPK α subunit at Thr-172 and acetyl-CoA carboxylase (ACC) at Ser<sup>79</sup>. Furthermore, berberine dose-dependently inhibited mTORC1 (phosphorylation of S6K at Thr<sup>389</sup> and S6 at Ser<sup>240/244</sup>) and ERK activation in PDAC cells stimulated by insulin and neurotensin or fetal bovine serum. Knockdown of α<sub>1</sub> and α<sub>2</sub> catalytic subunit expression of AMPK reversed the inhibitory effect produced by treatment with low concentrations of berberine on mTORC1, ERK and DNA synthesis in PDAC cells. However, at higher concentrations, berberine inhibited mitogenic signaling (mTORC1 and ERK) and DNA synthesis through an AMPK-independent mechanism. Similar results were obtained with metformin used at doses that induced either modest or pronounced reductions in intracellular ATP levels, which were virtually identical to the decreases in ATP levels obtained in response to berberine. We propose that berberine and metformin inhibit mitogenic signaling in PDAC cells through dose-dependent AMPK-dependent and independent pathways.</p></div>