Design, synthesis, and biological evaluation of quinazolin-4(3H)-one derivatives co-targeting poly(ADP-ribose) polymerase-1 and bromodomain containing protein 4 for breast cancer therapy

@#This study was aimed to design the first dual-target small-molecule inhibitor co-targeting poly (ADP-ribose) polymerase-1 (PARP1) and bromodomain containing protein 4 (BRD4), which had important cross relation in the global network of breast cancer, reflecting the synthetic lethal effect. A series of new BRD4 and PARP1 dual-target inhibitors were discovered and synthesized by fragment-based combinatorial screening and activity assays that together led to the chemical optimization. Among these compounds, 19d was selected and exhibited micromole enzymatic potencies against BRD4 and PARP1, respectively. Compound 19d was further shown to efficiently modulate the expression of BRD4 and PARP1. Subsequently, compound 19d was found to induce breast cancer cell apoptosis and stimulate cell cycle arrest at G1 phase. Following pharmacokinetic studies, compound 19d showed its antitumor activity in breast cancer susceptibility gene 1/2 (BRCA1/2) wild-type MDA-MB-468 and MCF-7 xenograft models without apparent toxicity and loss of body weight. These results together demonstrated that a highly potent dual-targeted inhibitor was successfully synthesized and indicated that co-targeting of BRD4 and PARP1 based on the concept of synthetic lethality would be a promising therapeutic strategy for breast cancer.

Bromodomain4 inhibitor JQ1 inhibits the proliferation of Ph positive acute lymphocytic leukemia cells and its mechanism / 白血病·淋巴瘤

Objective To observe the effect of bromodomain4 (brd4) inhibitor JQ1 on proliferation inhibition and apoptosis of Ph positive acute lymphocytic leukemia (Ph+ ALL) cells, and to explore the influence on the expression of brd4 and its downstream genes (myc and p53), and the reverse effect on bcr-abl.Methods Different concentrations of JQ1 were used on SUP-B15 cells.The proliferation inhibition rate was detected by MTT, the apoptosis rate was determined by flow cytometry (FCM), and the expressions of bcr-abl mRNA, brd4 mRNA, myc mRNA and p53 mRNA were detected by real-time fluorescent quantitative PCR (RT-PCR).Results Different concentrations of JQ1 inhibited SUP-B15 cells proliferation and induced cell apoptosis.The apoptosis rate was significantly increased compared with that in control group with a time-dose dependent manner.Median inhibitory concentration at 72 h was 1.0 pmol/L.At the same time, JQ1 decreased the transcription levels of bcr-abl mRNA, brd4 mRNA and myc mRNA, and increased the transcription level of p53 mRNA.Conclusions As a brd4 inhibitor, JQ1 can decrease the expression of brd4 to affect the expression of its downstream genes myc and p53, meanwhile, it can change the over expression of bcr-abl to suppress the proliferation of Ph+ ALL cells and induce apoptosis.