BET inhibitor JQ-1 combined with cardamonin can inhibit the invasion and metastasis of triple-negative breast cancer cells
Purpose: The BET family protein BRD4 is an important anti-tumor target and is highly expressed in breast cancer. However, BET inhibitors are susceptible to drug resistance. The aim of this study is to explore the mechanism of BET inhibitor JQ-1 combined with cardamonin in the anti-invasion and metastasis of triple-negative breast cancer. Methods: triple-negative breast cancer cells mRNA of DMSO (Control), JQ-1,cardamonin and combined groups were progressed with deep sequencing, in triplicate through Illumina sequencing platform (HiSeqTM 2500). Genes with adjusted P-value < 0.01 and |foldChange| > 2 were defined as differentially expressed genes (DEGs) and subjected to the following GO and KEGG enrichment. qRT-PCR was performed to validate several essential genes using QuantStudio 5 (Thermo Fisher) and SYBR Green assays. Results: As an inhibitor of mTOR, Cardamonin(CAR) can inhibit the proliferation of tumors. Research have found that BET inhibitor can affect the function of a large number of genes by regulating the epigenome, which plays an important role in a variety of diseases. In this study we explored the JQ1 which is a BRD4 protein inhibitor can inhibit the proliferation and metastasis of MDA-MB-231 cells in triple-negative breast cancer cell lines, and this phenomenon can be significantly enhanced when CAR is combined with JQ-1, and the same results are shown in mouse tumor formation experiments and triple-negative breast cancer organoids. At the same time, RNA-seq was performed in MD1-MB-231 cells to explore the changes of specific molecular signaling pathways. We have mapped over 40 million sequence reads to the MDA-MB-231 cell line genome in each specimen.Compared with the control group, CAR and JQ1, the combination group has significantly enriched gene expression. KEGG and GO enrichment analysis indicate that the combination group showed a series of biological processes such as macroautophagy, negative regulation of cell growth, lipid catabolic process, which led to decreased cell viability and decreased proliferation and metastasis ability. Conclusions: In this study, we demonstrated that JQ-1 combined with cardamomin could inhibit the invasion and metastasis of triple-negative breast cancer MDA-MB-231 cells, induce cell cycle arrest and promote cell apoptosis. The results of RNA-Seq were consistent with our in vitro and in vivo experiments, which demonstrated that the combination of JQ-1 and cardamonin effectively inhibited the proliferation, invasion and metastasis of MDA-MB-231 cells. Overall design: mRNA expression profiles of DMSO,JQ-1,CAR, and Combination groups.