The HDAC inhibitor GCJ-490A suppresses c-Met expression through IKKα and overcomes gefitinib resistance in non-small cell lung cancer

Objective:The novel compound GCJ-490A has been discovered as a pan-histone deacetylase(HDAC)inhibitor that exerts potent inhibitory activity against HDAC1,HDAC3,and HDAC6.Because of the important roles of HDACs in lung cancer development and the high distribution of GCJ-490A in lung tissue,we explored the anti-tumor potency of GCJ-490A against non-small cell lung cancer(NSCLC)in vitro and in vivo in this study.Methods:The in vitro effects of GCJ-490A alone or combined with the EGFR inhibitor gefitinib against NSCLC were measured with proliferation,apoptosis,and colony formation assays.NSCLC xenograft models were used to investigate the efficacy of GCJ-490A combined with gefitinib for the treatment of NSCLC in vivo.Western blot assays,luciferase reporter assays,chromatin immunoprecipitation assays,quantitative real time-PCR,immunohistochemistry,and transcription factor activity assays were used to elucidate possible mechanisms.Results:GCJ-490A effectively inhibited NSCLC cell proliferation and induced apoptosis in vitro and in vivo.Interestingly,inhibition of HDAC1 and HDAC6 by GCJ-490A increased histone acetylation at the IKKαpromoter and enhanced IKKαtranscription,thus decreasing c-Met.Moreover,this c-Met downregulation was found to be essential for the synergistic anti-tumor activity of GCJ-490A and gefitinib.Conclusions:These findings highlight the promising potential of HDAC inhibitors in NSCLC treatment and provide a rational basis for the application of HDAC inhibitors in combination with EGFR inhibitors in clinical trials.

Development of the novel ACLY inhibitor 326E as a promising treatment for hypercholesterolemia

Hepatic cholesterol accumulation is an important contributor to hypercholesterolemia,which results in atherosclerosis and cardiovascular disease(CVD).ATP-citrate lyase(ACLY)is a key lipogenic enzyme that converts cytosolic citrate derived from tricarboxylic acid cycle(TCA cycle)to acetyl-CoA in the cytoplasm.Therefore,ACLY represents a link between mitochondria oxidative phosphorylation and cytosolic de novo lipogenesis.In this study,we developed the small molecule 326E with an enedioic acid structural moiety as a novel ACLY inhibitor,and its CoA-conjugated form 326E-CoA inhibited ACLY activity with an IC_(50)=5.31±1.2μmol/L in vitro.326E treatment reduced de novo lipogenesis,and increased cholesterol efflux in vitro and in vivo.326E was rapidly absorbed after oral administration,exhibited a higher blood exposure than that of the approved ACLY inhibitor bempedoic acid(BA)used for hypercholesterolemia.Chronic 326E treatment in hamsters and rhesus monkeys resulted in remarkable improvement of hyperlipidemia.Once daily oral administration of 326E for 24 weeks prevented the occurrence of atherosclerosis in ApoE^(-/-)mice to a greater extent than that of BA treatment.Taken together,our data suggest that inhibition of ACLY by 326E represents a promising strategy for the treatment of hypercholesterolemia.

Disruption of adipocyte HIF-1α improves atherosclerosis through the inhibition of ceramide generation

Atherosclerosis is a chronic multifactorial cardiovascular disease.Western diets have been reported to affect atherosclerosis through regulating adipose function.In high cholesterol diet-fed ApoE^(−/−)mice,adipocyte HIF-1αdeficiency or direct inhibition of HIF-1αby the selective pharmacological HIF-1αinhibitor PX-478 alleviates high cholesterol diet-induced atherosclerosis by reducing adipose ceramide generation,which lowers cholesterol levels and reduces inflammatory responses,resulting in improved dyslipidemia and atherogenesis.Smpd3,the gene encoding neutral sphingomyelinase,is identified as a new target gene directly regulated by HIF-1αthat is involved in ceramide generation.Injection of lentivirus-SMPD3 in epididymal adipose tissue reverses the decrease in ceramides in adipocytes and eliminates the improvements on atherosclerosis in the adipocyte HIF-1α-deficient mice.Therefore,HIF-1αinhibition may constitute a novel approach to slow atherosclerotic progression.

Synthetic Analogues of Betulinic Acid as Potent Inhibitors of PS1/BACE1 Interaction to Reduce Aβ Generation

The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer＇s disease （AD） treatment as an inhibitor of PS1/BACE1 interaction. 3-a-Akebonoic acid, which emanated from a high throughput screening （HTS）, was discovered to interfere with P S 1/BACE 1 interaction and reduce amyloid β-protein （Aβ） production. In view of the limited source, we instead used naturally rich betulinic acid （compound 2） as starting material for lead optimization and a focused library of its derivatives was constructed to gain a better understanding of the structure activity relationship （SAR） of triterpenoid-type inhibitor of PS1/BACE1 interaction. Compound 22 was finally chosen as the most potent PS 1/BACE 1 interaction inhibitor, which reduced Aβgeneration effectively.