Identification of Pyruvate Carboxylase as the Cellular Target of Natural Bibenzyls with Potent Anticancer Activity against Hepatocellular Carcinoma via Metabolic Reprogramming.

Cancer cell proliferation in some organs often depends on conversion of pyruvate to oxaloacetate via pyruvate carboxylase (PC) for replenishing the tricarboxylic acid cycle to support biomass production. In this study, PC was identified as the cellular target of erianin using the photoaffinity labeling-click chemistry-based probe strategy. Erianin potently inhibited the enzymatic activity of PC, which mediated the anticancer effect of erianin in human hepatocellular carcinoma (HCC). Erianin modulated cancer-related gene expression and induced changes in metabolic intermediates. Moreover, erianin promotes mitochondrial oxidative stress and inhibits glycolysis, leading to insufficient energy required for cell proliferation. Analysis of 14 natural analogs of erianin showed that some compounds exhibited potent inhibitory effects on PC. These results suggest that PC is a cellular target of erianin and reveal the unrecognized function of PC in HCC tumorigenesis; erianin along with its analogs warrants further development as a novel therapeutic strategy for the treatment of HCC.

(-)-Gochnatiolide B, synthesized from dehydrocostuslactone, exhibits potent anti-bladder cancer activity in vitro and in vivo.

With limited success achieved in bladder cancer patient management, novel agents are in urgent need for the purpose of therapy and prevention. As a sesquiterpenoid dimmer isolated from Gochnatia pomculat, (-)-gochnatiolide B has been bio-mimetically synthesized in multiple steps with a poor yield, which heavily limited the further research and clinical application. Herein, (-)-gochnatiolide B was synthesized beginning with dehydrocostuslactone in four steps with a total yield of 26%. MTT assays showed that (-)-gochnatiolide B inhibited the growth of vast majority of human cancer cells especially bladder cancer cells. Mechanistically, (-)-gochnatiolide B induced the increased expression of pro-apoptotic proteins and the decreased expression of anti-apoptosis proteins and further resulted in apoptosis of T24 cells. (-)-Gochnatiolide B induced G1 arrest which associated with SKP2 downregulation, leading to p27/Kip1 accumulation and downregulation of cyclin D1 in T24 cells. Furthermore, in vivo studies showed that (-)-gochnatiolide B remarkably inhibited tumor growth by 81% compared with vehicle control. Taken together, (-)-gochnatiolide B exhibits inhibitory activity against bladder cancer cells both in vitro and in vivo by inducing apoptosis, which suggests that (-)-gochnatiolide B could be an important candidate compound for prevention and treatment of bladder cancer.

Characterization of in vitro metabolites of irisflorentin by rat liver microsomes using high-performance liquid chromatography coupled with tandem mass spectrometry.

Belamcanda chinensis has been extensively used as antibechic, expectorant and anti-inflammatory agent in traditional medicine. Irisflorentin is one of the major active ingredients. However, little is known about the metabolism of irisflorentin so far. In this work, rat liver microsomes (RLMs) were used to investigate the metabolism of this compound for the first time. Seven metabolites were detected. Five of them were identified as 6,7-dihydroxy-5,3',4',5'-tetramethoxy isoflavone (M1), irigenin (M2), 5,7,4'-trihydroxy-6,3',5'-trimethoxy isoflavone (M3), 6,7,4'-trihydroxy-5,3',5'-trimethoxy isoflavone (M4) and 6,7,5'-trihydroxy-5,3',4'-trimethoxy isoflavone (M5) by means of NMR and/or HPLC-ESI-MS. The structures of M6 and M7 were not elucidated because they produced no MS signals. The predominant metabolite M1 was noted to be a new compound. Interestingly, it was found to possess anticancer activity much higher than the parent compound. The enzymatic kinetic parameters of M1 revealed a sigmoidal profile, with Vmax = 12.02 µm/mg protein/min, Km = 37.24 µm, CLint = 0.32 µL/mg protein/min and h = 1.48, indicating the positive cooperation. For the first time in this work, a new metabolite of irisflorentin was found to demonstrate a much higher biological activity than its parent compound, suggesting a new avenue for the development of drugs from B. chinensis, which was also applicable for other herbal plants. Copyright © 2016 John Wiley & Sons, Ltd.