Luteolin Inhibits Breast Cancer Development and Progression In Vitro and In Vivo by Suppressing Notch Signaling and Regulating MiRNAs.

BACKGROUND/AIMS: This study aims to investigate the effect of Luteolin on breast cancer in vitro and in vivo and the interaction between miRNAs and Notch signaling after Luteolin intervention, and illustrates the possible underlying mechanism and regulation loop. METHODS: Cell growth/survival assays and cell cycle analyses were performed to evaluate cell survival in vitro. Scratch tests, cell invasion assays and tube formation assays were carried out to analyze cell viability and identify the impact of Luteolin on angiogenesis. Critical components in the Notch pathway including proteins and mRNAs were detected by Western blotting analyses, ELISA assays and real-time reverse transcription-polymerase chain reaction. Matrix metalloproteinases activity was evaluated by gelatin zymography analyses. MiRNAs were analyzed by miRNA expression assays. After MDA-MB-231 cells were separately transfected with Notch-1 siRNA/cDNA and miRNA mimics, the above assays were also carried out to examine potential tumor cell changes. Xenograft models were applied to evaluate the treatment potency of Luteolin in breast cancer. RESULTS: Luteolin significantly inhibited breast cancer cell survival, cell cycle, tube formation and the expression of Notch signaling-related proteins and mRNAs, and regulated miRNAs. After introducing Notch-1 siRNA and miRNA mimics, MDA-MB-231 cells presented with changes in miRNA levels, reduced Notch signaling-related proteins, and decreased tumor survival, invasion and angiogenesis. CONCLUSION: Luteolin inhibits Notch signaling by regulating miRNAs. However, the effect of miRNAs on the Notch pathway could be either Luteolin-dependent or Luteolin-independent. Furthermore, Notch-1 alteration may inversely change miRNAs levels. Our data demonstrates that Luteolin, miRNAs and the Notch pathway are critical in breast cancer development and prognosis.

ß-elemene reverses chemoresistance of breast cancer via regulating MDR-related microRNA expression.

BACKGROUND: Multidrug resistance (MDR) directly contributes to the clinical failure of chemotherapy in breast cancer (BCA). ß-elemene is a natural antitumor drug from plants. We previously confirmed that MDR could be reversed by ß-elemene. In this study, we intended to investigate the reversal effect of ß-elemene on MDR in human BCA adriacin (Adr) -resistant MCF-7 cells (MCF-7/Adr) and docetaxel (Doc) - resistant MCF-7 cells (MCF-7/Doc) through the gene regulatory network. METHODS: MTT-cytotoxic, miRNA microarray, Real-time quantitative PCR, Dual Luciferase Activity Assay, Western blot analysis were performed to investigate the impact of ß-elemene on chemo-resistant BCA cell suvival, and its impact on the expression of chemo-resistance specific miRNA and the downstream target genes PTEN and Pgp. RESULTS: Compared with the miRNAs expression profiles of MCF-7/Adr and MCF-7/Doc cell lines from our previous studies, there were 322 differentially expressed miRNAs in MCF-7/Adr and MCF-7/Doc breast cancer cells with ß-elemene intervention (50µM/L) for 30h, and 6 miRNAs were significantly up-regulated and 12 miRNAs were significantly down-regulated in both MCF-7/Adr and MCF-7/Doc. We have testified that 5 miRNA is related to MDR before, in this study, the expression of miR-34a, miR-222, miR-452 and miR-29a can lead to changes of the characteristics of chemo-resistant MCF-7/Adr and MCF-7/Doc. The PTEN expression under intervention of ß-elemene was significantly increased and Pgp expression under ß-elemene intervention was significantly decreased in both cell lines. CONCLUSIONS: ß-elemene could influence MDR related miRNA expression and subsequently regulate the expression of the target genes PTEN and Pgp, which may lead to reduction of the viability of the chemo-resistant breast cancer cells.

Circular RNA hsa_circ_0072995 promotes breast cancer cell migration and invasion through sponge for miR-30c-2-3p.

AIM: To study the role of hsa_circ_0072995 in regulating the invasion and migration of breast cancer cells. MATERIALS & METHODS: Hsa_circ_0072995 expression was confirmed by quantitative real-time PCR; evaluating the migration and invasion of breast cancer cells through transwell assay; predicating circRNA/microRNAs interaction using the miRanda and RNAhybrid software; identifying the relationship between hsa_circ_0072995 and miR-30c-2-3p by luciferase activity assay; detecting the location of hsa_circ_0072995 by Fluorescence in situ hybridization assay. RESULTS: Hsa_circ_0072995 was significantly upregulated in MDA-MB-231 cells compared with MCF-7 cells. Hsa_circ_0072995 regulated the invasion and migration of breast cancer cells. Hsa_circ_0072995 existed in the nucleus and cytoplasm, and the proportion of the two was roughly equal. Hsa_circ_0072995 bound to miR-30c-2-3p. Overexpression of miR-30c-2-3p inhibited breast cancer cells migration and invasion. Low expression of miR-30c-2-3p was correlated with poor overall survival by The Cancer Genome Atlas database. CONCLUSION: Hsa_circ_0072995 may be a novel biomarker for breast cancer, and may function in metastasis of breast cancer.

Association between the XRCC3 Thr241Met polymorphism and breast cancer risk: an updated meta-analysis of 36 case-control studies.

BACKGROUND: The X-ray repair cross-complementing group 3 (XRCC3) is a highly suspected candidate gene for cancer susceptibility. Attention has been drawn upon associations of the XRCC3 Thr241Met polymorphism with breast cancer risk. However, the previous published findings remain controversial. Hence, we performed a meta-analysis to accurately evaluate any association between breast cancer and XRCC3 T241M (23, 812 cases and 25, 349 controls) in different inheritance models. MATERIALS AND METHODS: PubMed and Web of Science databases were searched systematically until December 31, 2013 to obtain all the records evaluating the association between the XRCC3 Thr241Met polymorphism and breast cancer risk. Crude odds ratios (ORs) together with 95% confidence intervals (CIs) were used to assess the strength of associations. RESULTS: When all eligible studies were pooled into the meta analysis of XRCC3 T241M polymorphism, a significantly increased breast cancer risk was observed in heterozygote comparison (OR=1.06, 95%CI=1.01-1.12). No significant associations were found in other models. In subgroup analysis, this polymorphism seemed to be associated with elevated breast risk in Asians. No publication bias was detected. CONCLUSIONS: This meta-analysis suggests that the T241M polymorphism confers a weakly increased breast cancer risk. A study with the larger sample size is needed to further evaluate gene-gene and gene-environment interactions of the XRCC3 T241M polymorphism with breast cancer risk.