Design, synthesis and evaluation of new pyrimidine derivatives as EGFRC797S tyrosine kinase inhibitors.

The clinical use of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in the treatment of non-small cell lung cancer was limited by the drug resistance caused by EGFRC797S mutation. Therefore, in order to overcome the drug resistance, we designed and synthesized a series of 2-aminopyrimidine derivatives as EGFRC797S-TKIs. Among these compounds, compounds A5 and A13 showed significant anti-proliferative activity against the KC-0116 (EGFRdel19/T790M/C797S) cell line with high selectivity. A5 inhibited EGFR phosphorylation and induced apoptosis of KC-0116 cell, arrested KC-0116 cell at G2/M phase. Molecular docking results showed that A5 and brigatinib bind to EGFR in a similar pattern. In addition to forming two important hydrogen bonds with Met793 residue, A5 also formed a hydrogen bond with Lys745 residues, which may play an important role for the potent inhibitory activity against EGFRdel19/T790M/C797S. Based on these results, A5 turned out to be effective reversible EGFRC797S-TKIs which can be further developed.

Transcription factor Klf9 controls bile acid reabsorption and enterohepatic circulation in mice via promoting intestinal Asbt expression.

Bile acid (BA) homeostasis is regulated by the extensive cross-talk between liver and intestine. Many bile-acid-activated signaling pathways have become attractive therapeutic targets for the treatment of metabolic disorders. In this study we investigated the regulatory mechanisms of BA in the intestine. We showed that the BA levels in the gallbladder and faeces were significantly increased, whereas serum BA levels decreased in systemic Krüppel-like factor 9 (Klf9) deficiency (Klf9-/-) mice. These phenotypes were also observed in the intestine-specific Klf9-deleted (Klf9vil-/-) mice. In contrast, BA levels in the gallbladder and faeces were reduced, whereas BA levels in the serum were increased in intestinal Klf9 transgenic (Klf9Rosa26+/+) mice. By using a combination of biochemical, molecular and functional assays, we revealed that Klf9 promoted the expression of apical sodium-dependent bile acid transporter (Asbt) in the terminal ileum to enhance BA absorption in the intestine. Reabsorbed BA affected liver BA synthetic enzymes by regulating Fgf15 expression. This study has identified a previously neglected transcriptional pathway that regulates BA homeostasis.

[KLF9 regulates hepatic lipid metabolism via inducing CD36 expression].

The development of nonalcoholic fatty liver disease (NAFLD) is closely related to the fatty acid (FA) uptake. This study aimed to investigate the effect of Krüppel-like factor 9 (KLF9) on CD36 (typical fatty acid translocase), hepatocellular lipid metabolism as well as the development and progression of nonalcoholic fatty liver. High-fat diet-induced obese C57BL/6J mice and db/db mice were used to test the expression levels of Klf9 and Cd36 in the livers. The primary hepatocytes were isolated from C57BL/6J mice, treated with Ad-GFP, Ad-Klf9, Ad-shCtrl or Ad-shKlf9, and then incubated with oleic acid and palmitic acid for 24 h. Liver-specific knockout of Klf9 mice were established. The protein levels and relative mRNA levels were examined by Western blot and real-time PCR, respectively. Triglyceride content was determined by using an assay kit. Lipid content was determined by Oil Red O staining. The results showed that: (1) Klf9 expression levels were increased in the livers of high-fat diet-induced obese mice and db/db mice, compared to their respective control mice. (2) Adenovirus-mediated overexpression of Klf9 in primary hepatocytes increased Cd36 expression and cellular triglyceride contents. (3) In contrast, adenovirus-mediated knockdown of Klf9 expression in primary hepatocytes by Ad-shKlf9 decreased Cd36 expression and cellular triglyceride contents. (4) Finally, Klf9 deficiency decreased liver Cd36 expression and alleviated fatty liver phenotype of high-fat diet-induced obese mice. These results suggest that KLF9 can regulate hepatic lipid metabolism and development of NAFLD by promoting the expression of CD36.