GSE137418
Thioguanine suppresses growth in triple-negative breast  cancer by inhibiting PI3K-AKT pathway and inducing apoptosis
Triple-negative breast cancer (TNBC) is difficult to treat due to the lack of biological targets and poor sensitivity to conventional therapies. Chemotherapy is the main treatment in the clinic, but there is still no effective screening strategy for chemotherapy drugs. Several studies have attempted to find the pathogenesis through sequencing, but the integration of transcriptome maps of various tumors for drug discovery has been slow. Drug repurposing has attracted increasing attention in recent years. We first found there were common features between leukemia and TNBC. Therefore, we chose a classic leukemia drug thioguanine (6-TG) as a candidate drug. We utilized RNA-seq and DNA methylation arrays to evaluate its role in MDA-MB-231 cells. Our results demonstrated that 6-TG inhibited cell proliferation by suppressing PI3K-AKT pathway via downregulating the DNA methylation level of PTEN. Moreover, apoptosis was induced via the activation of PI3K-AKT downstream molecular TSC1 and the downregulation of methylation levels of DAXX, TNF, FADD and CASP8 etc., these genes involved in apoptosis pathways. 6-TG presents anti-tumor effects in vitro and vivo by regulating the DNA methylation levels of PI3K-AKT pathway and apoptosis pathway. Meanwhile, we proved transcriptome-based drug screening has potential implications for breast cancer therapy and drug selection. Overall design: effect of 6-TG on MDA-MB-231 cells