Anti-GATA4 monoclonal antibody, clone 680DU20.6.8

Pathological stresses such as pressure overload and myocardial infarction induce cardiac hypertrophy, which increases the risk of heart failure. Cacao bean polyphenols have recently gained considerable attention for their beneficial effects on cardiovascular diseases. This study investigated the effect of cacao bean polyphenols on the development of cardiac hypertrophy and heart failure. Cardiomyocytes from neonatal rats were pre-treated with cacao bean polyphenols and then stimulated with 30 mu M phenylephrine. C57BL/6j male mice were subjected to sham or transverse aortic constriction surgery and then orally administered with vehicle or cacao bean polyphenols. Cardiac hypertrophy and function were examined by echocardiography. In cardiomyocytes, cacao bean polyphenols significantly suppressed phenylephrine-induced cardiomyocyte hypertrophy and hypertrophic gene transcription. Extracellular signal-regulated kinase 1/2 and GATA binding protein 4 phosphorylation induced by phenylephrine was inhibited by cacao bean polyphenols treatment in the cardiomyocytes. Cacao bean polyphenols treatment at 1200mg/kg significantly ameliorated left ventricular posterior wall thickness, fractional shortening, hypertrophic gene transcription, cardiac hypertrophy, cardiac fibrosis, and extracellular signal-regulated kinase 1/2 phosphorylation induced by pressure overload. In conclusion, these findings suggest that cacao bean polyphenols prevent pressure overload-induced cardiac hypertrophy and systolic dysfunction by inhibiting the extracellular signal-regulated kinase 1/2-GATA binding protein 4 pathway in cardiomyocytes. Thus, cacao bean polyphenols may be useful for heart failure therapy in humans.

Rationale: Effective targeting therapies are limited in Hepatocellular carcinoma (HCC) clinic. Characterization of tumor suppressor genes (TSGs) and elucidation their signaling cascades could shed light on new strategies for developing targeting therapies for HCC. Methods: We checked genome-wide DNA copy number variation (CNV) of HCC samples, focusing on deleted genes for TSG candidates. Clinical data, in vitro and in vivo data were collected to validate the tumor suppressor functions. Results: Focal deletion of GATA4 gene locus was the most prominent feature across all liver cancer samples. Ectopic expression of GATA4 resulted in senescence of HCC cell lines. Mechanistically, GATA4 exerted tumor suppressive role by orchestrating the assembly of a tumor suppressor enhancing module: GATA4 directly bound and potently inhibited the mRNA transcription activity of beta-catenin; meanwhile, beta-catenin was recruited by GATA4 to promoter regions and facilitated transcription of GATA4 target genes, which were TSGs per se. Expression of GATA4 was effective to shrink GATA4-deficient HCC tumors in vivo. We also showed that beta-catenin inhibitor was capable of shrinking GATA4-deficient tumors. Conclusions: Our study unveiled a previously unnoticed tumor suppressor enhancing module assembled by ectopically expressed GATA4 in HCC cells and denoted a therapeutic opportunity for GATA4 deficient HCC patients. Our study also presented an interesting case that an oncogenic transcription factor conditionally functioned as a tumor suppressor when recruited by a TSG transcription factor.