Induced expression of miR-1250-5p exerts tumor suppressive role in triple-negative breast cancer cells

Piper chaba, an Indian spice plant extract, inhibits cell cycle G1/S phase transition and induces intrinsic apoptotic pathway in luminal breast cancer cells

Piper chaba (Piperaceae) is a medicinal spice plant that possesses several pharmacological activities. In the present study, we for the first time studied the effect of P. chaba extract on breast cancer cells. P. chaba stem methanolic (PCSM) extract produced time and dose dependent cytotoxicity in luminal breast cancer cells (MCF-7 and T47D) with a minimal toxicity in breast normal cells (MCF-10A) at 10-100 µg/mL concentration. PCSM extract exerts 16.79 and 31.21 µg/mL IC50 for T47D and MCF-7 cells, respectively, in 48 h treatment. PCSM significantly arrests the T47D cells at the G0/G1 phase by reducing the CCND1 and CDK4 expression at mRNA and protein levels. PCSM extract treatment significantly altered nuclear morphology, mitochondria membrane potential, and production of reactive oxygen species in T47D cells at IC50 concentration. Extract treatment significantly altered the Bax/Bcl-2 ratio and altered caspase 8 and 3 mRNA/protein levels in T47D cells. Confocal microscopy showed an increase in late apoptosis in PCSM extract-treated breast cancer cells at IC50 . Further, an increased caspase 9 and caspase 3/7 enzymatic activity was observed in test cells compared with nontreated cells. In conclusion, P. chaba phytocompound possesses the potential to induce cell cycle arrest and induce apoptosis in luminal breast cancer cells.

Discovery of differentially expressed novel miRNAs in breast normal cells and their putative targets

MicroRNAs (miRNAs) play critical role in normal breast development and their altered expression may lead to breast cancer. Identification of new miRNAs allows us to understand the normal physiological process and associated disease pathophysiology. In the present study we identify the novel miRNAs in withaferin A treated breast normal cells (MCF-10A) using small RNA sequencing. The pathophysiological potential of the identified miRNAs was checked by studying their expression pattern in MDA-MB-231 and MCF-7 breast cancer cells using qRT-PCR technique. The secondary/tertiary structure of the identified miRNAs, target gene enrichment in Gene Ontology terms and KEGG pathway, miRNA-mRNA interaction of the sorted target genes, miRNA-mRNA/miRNA-argonaute protein/miRNA-mRNA-argonaute protein interaction and stability, were studied using bioinformatics tools/software, and molecular dynamics simulations. Hsa-miR-N88585 and hsa-miR-N461089 were identified and validated as novel miRNAs in normal breast cells. Up-expression of identified miRNAs in MDA-MB-231 and MCF-7 cells indicates their oncogenic nature. Identified target genes were enriched in classical signaling pathways (AMPK and Ras) and important GO terms. PLXDC2, BHLHE40, ARMC8, and PECAM1, CDC27, KCNK3 genes were sorted as putative targets for hsa-miR-N88585 and hsa-miR-N461089, respectively. MD simulation revealed stable hsa-miR-N88585/hsa-miR-N461089-AGO protein complex formation which indicates their further processing. In conclusion, the study identifies hsa-miR-N88585 and hsa-miR-N461089 as novel miRNAs in breast normal cells which are significantly inversely expressed in breast cancer cells. Further experiments are required to study the role of identified novel miRNAs in normal breast development and pathophysiology of breast cancer.