Ginsenoside Rg1 Induces Apoptotic Cell Death in Triple-Negative Breast Cancer Cell Lines and Prevents Carcinogen-Induced Breast Tumorigenesis in Sprague Dawley Rats.

The objective of this study is to investigate the anticancer potential of ginsenoside Rg1 using in vitro and in vivo experimental models. In this study, we found that ginsenoside Rg1 induces cytotoxicity and apoptotic cell death through reactive oxygen species (ROS) generation and alterations in mitochondrial membrane potential (MMP) in the triple-negative breast cancer cells (MDA-MB-MD-231 cell lines). We found that ginsenoside Rg1 induces the formation of gamma H2AX foci, an indication of DNA damage, and subsequent TUNEL positive apoptotic nuclei in the MDA-MB-MD-231 cell lines. Further, we found that ginsenoside Rg1 prevents 7,12-dimethylbenz (a) anthracene (DMBA; 20 mg/rat) induced mammary gland carcinogenesis in experimental rats. We observed oral administration of ginsenoside Rg1 inhibited the DMBA-mediated tumor incidence, prevented the elevation of oxidative damage markers, and restored antioxidant enzymes near to normal. Furthermore, qRT-PCR gene expression studies revealed that ginsenoside Rg1 prevents the expression of markers associated with cell proliferation and survival, modulates apoptosis markers, downregulates invasion and angiogenesis markers, and regulates the EMT markers. Therefore, the present results suggest that ginsenoside Rg1 shows significant anticancer properties against breast cancer in experimental models.

ZEB1 Promotes Chemoresistance to Cisplatin in Ovarian Cancer Cells by Suppressing SLC3A2.

Ovarian cancer is one of the deadliest gynecological malignancies in women. Chemoresistance has been a major obstacle for ovarian cancer treatment. Zinc finger E-box-binding homeobox 1 (ZEB1) is an important regulator of tumor development in various types of cancer. Abnormal expression of SLC3A2 (CD98hc), a type 2 transmembrane cell surface molecule, has been described in several cancers. This study was designed to investigate the role of ZEB1 and SLC3A2 in the chemoresistance to cisplatin in ovarian cancer cells. We found that ZEB1 was increased in cisplatin-resistant SKOV3/DPP cells. Downregulation of ZEB1 significantly decreased cell viability in response to cisplatin, increased cis-platin-induced apoptosis, and decreased migration and invasion in the presence of cisplatin. In addition, downregulation of ZEB1 decreased the volume and weight of implanted tumors. SLC3A2 was decreased in cisplatin-resistant SKOV3/DPP cells. Upregulation of SLC3A2 significantly decreased cell viability in response to cisplatin, increased cisplatin-induced apoptosis, and decreased migration and invasion in the presence of cisplatin. Moreover, upregulation of SLC3A2 decreased the volume and weight of implanted tumors. Downregulation of ZEB1 resulted in a significant increase of SLC3A2 expression. Moreover, downregulation of SLC3A2 significantly inhibited ZEB1 knockdown-mediated inhibition of cisplatin-resistance. ZEB1-mediated regulation of SLC3A2 was involved in the chemoresistance to cisplatin in ovarian cancer cells. Overall, we provide new insights into the mechanism of chemoresistance to cisplatin in ovarian cancer cells. ZEB1/SLC3A2 may be promising therapeutic targets for enhancement of the sensitivity of ovarian cancer cells to cisplatin-mediated chemotherapy.

miR-199a-3p enhances cisplatin sensitivity of ovarian cancer cells by targeting ITGB8.

Drug resistance remains a large obstacle for the treatment of ovarian cancer. miRNAs have been reported to be involved in cisplatin (CDDP) resistance in ovarian cancer. The aim of the present study was to investigate the function and mechanism of miR-199a-3p in the CDDP resistance in ovarian cancer. We found that miR-199a-3p was significantly downregulated in chemoresistant ovarian cancer tissues, as well as CDDP-resistant SKOV3/CDDP cells, compared to chemosensitive carcinomas and SKOV3 cells. Restoration of miR-199a-3p in SKOV3/CDDP cells reduced cell proliferation, G1 phase cell cycle arrest, cell invasion, and increased cell apoptosis, resulting in enhanced CDDP sensitivity, while miR-199a-3p inhibition resulted in the opposite effects. Luciferase reporter assay showed that integrin ß8 (ITGB8), one of the integrins that is involved in the regulation of cell cycle and motility, was a direct target of miR-199a-3p. Overexpression of miR-199a-3p downregulated ITGB8 expression via binding to its 3'-UTR. In addition, overexpression of ITGB8 restored CDDP resistance inhibited by miR-199a-3p. Moreover, orthotopic ovarian cancer mouse model showed that miR­199a-3p enhanced CDDP sensitivity of ovarian cancer in vivo. Therefore, our results indicate that miR-199a-3p enhances CDDP sensitivity of ovarian cancer cells through downregulating ITGB8 expression, and miR-199a-3p may serve as a therapeutic target for the treatment of ovarian cancer patients with CDDP-resistance.

miR-146a Inhibits Proliferation and Enhances Chemosensitivity in Epithelial Ovarian Cancer via Reduction of SOD2.

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy, accounting for 90% of all ovarian cancer. Dysregulation of miRNAs is associated with several types of EOC. In the current research, we aimed to study the role of abnormal expression of miR-146a in the development of EOC and to elucidate the possible molecular mechanisms. Compared with control samples, mRNA expression of miR-146a was significantly decreased in EOC tissues and cell lines. Overexpression of miR-146a prohibited cell proliferation, enhanced apoptosis, and increased sensitivity to chemotherapy drugs in EOC cells. In contrast, downregulation of miR-146a promoted cell proliferation, suppressed apoptosis, and decreased sensitivity to chemotherapy drugs in EOC cells. Overexpression of miR-146a increased the reactive oxygen species (ROS) level and decreased SOD2 mRNA and protein expression. Downregulation of miR-146a increased SOD2 mRNA and protein expression. Overexpression of SOD2 significantly inhibited miR-146a mimics-induced suppression of cell proliferation and the increase of apoptosis and chemosensitivity. In conclusion, we identify miR-146a as a potential tumor suppressor in patients with EOC. miR-146a downregulates the expression of SOD2 and enhances ROS generation, leading to increased apoptosis, inhibition of proliferation, and enhanced sensitivity to chemotherapy. The data demonstrate that the miR-146a/SOD2/ROS pathway may serve as a novel therapeutic target and prognostic marker in patients with EOC.