Arachidonic acid released by PIK3CA mutant tumor cells triggers malignant transformation of colonic epithelium by inducing chromatin remodeling.

Key gene mutations are essential for colorectal cancer (CRC) development; however, how the mutated tumor cells impact the surrounding normal cells to promote tumor progression has not been well defined. Here, we report that PIK3CA mutant tumor cells transmit oncogenic signals and result in malignant transformation of intestinal epithelial cells (IECs) via paracrine exosomal arachidonic acid (AA)-induced H3K4 trimethylation. Mechanistically, PIK3CA mutations sustain SGK3-FBW7-mediated stability of the cPLA2 protein, leading to the synthetic increase in AA, which is transported through exosome and accumulated in IECs. Transferred AA directly binds Menin and strengthens the interactions of Menin and MLL1/2 methyltransferase. Finally, the combination of VTP50469, an inhibitor of the Menin-MLL interaction, and alpelisib synergistically represses PDX tumors harboring PIK3CA mutations. Together, these findings unveil the metabolic link between PIK3CA mutant tumor cells and the IECs, highlighting AA as the potential target for the treatment of patients with CRC harboring PIK3CA mutations.

Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry.

The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ±â€¯0.007 µM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ±â€¯0.5 µM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 µM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 µM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.

Discovery of a tetrahydroisoquinoline-based HDAC inhibitor with improved plasma stability.

Histone deacetylase inhibitors with desirable pharmacokinetic profiles which can be delivered to solid tumor tissues in large amount might be promising to treat solid tumor effectively. Herein, structural modification of a previously reported tetrahydroisoquinoline-based HDAC inhibitor 1 was carried out to improve its plasma stability for more feasible drug delivery. Among three newly synthesized analogs, the in vitro rat plasma stability of compound 2 (t1/2=630min) was over 5-fold improved than its parent 1 (t1/2=103min). In vitro activity evaluation showed that compound 2 and 1 exhibited similar HDACs inhibitory activity, which was validated by western blot analysis and antiproliferative assay. Moreover, compared with 1, compound 2 exhibited comparable, if not higher, in vivo antitumor activity in a human breast carcinoma (MDA-MB-231) xenograft model.

Inhibition of MEF2A prevents hyperglycemia-induced extracellular matrix accumulation by blocking Akt and TGF-ß1/Smad activation in cardiac fibroblasts.

Myocyte enhancer factor 2A (MEF2A) functions in muscle-specific and/or growth factor-related transcription and is involved in cell growth, survival, and apoptosis. To evaluate the role of this transcription factor in cardiac fibroblasts (CFs) in diabetes mellitus, we performed a series of in vitro and in vivo experiments. We used short hairpin RNA (shRNA) to inhibit the expression of MEF2A in CFs in vitro. Inhibition of MEF2A significantly reduced hyperglycemia-induced CF proliferation and migration, myofibroblast differentiation, matrix metalloproteinase (MMP) activities, and collagen production. Furthermore, MEF2A inhibition attenuated HG-induced activation of the mitogen-activated protein kinase (MAPK), Akt, and TGF-ß1/Smad signaling pathways. For in vivo analysis in a mouse model, type-1 diabetes was induced by streptozotocinand MEF2A expression was knocked down by myocardial injection with lentivirus carrying shRNA-MEF2A. Cardiac function was assessed by echocardiography. Total collagen deposition was assessed by Masson's trichrome and Picrosirius red staining. Knockdown of MEF2A ameliorated diabetes-induced cardiac dysfunction and collagen deposition. Our study suggests that inhibition of MEF2A could alleviate HG-induced extracellular matrix accumulation by blocking the activation of Akt and TGF-ß1/Smad signaling pathway in CFs. Thus, inhibition of MEF2A has therapeutic potential in the treatment of diabetic-induced cardiac remodeling.

Synthesis and antiproliferative assay of 1,3,4-oxadiazole and 1,2,4-triazole derivatives in cancer cells.

A series of new 1,3,4-oxadiazole and 1,2,4-triazole derivatives were synthesized. The structures were confirmed by IR, (1)H-NMR, and MS. The compounds were evaluated for their antiproliferative activity against K562 (human erythromyeloblastoid leukemia cell line), MDA-MB-231 (human breast adenocarcinoma cell line), HT29 (human colon adenocarcinoma grade II cell line) and HepG2 (human hepatocellular liver carcinoma cell line) in vitro. The result showed that 7 compounds displayed inhibitory activities against K562 with the inhibition rate more than 50%. Especially, compound 5f exhibited the most potent activity against K562 with 85% inhibition ratio and could be used as lead compound to search new 1,3,4-oxadiazole derivatives as antiproliferative agent.