MiR-142-3p target hmgb1 reverses adriamycin resistance of breast cancer cell mcf-7 / 中国药理学通报

Aim To explore the molecular mechanism of miR-142-3p involved in the regulation of chemosen-sitivity of breast cancer by targeting high-mobility group box 1 ( HMGB1 ). Methods Real-time quantitative PCR ( QPCR) was employed to detect the levels of miR-142-3p in human breast cancer MCF-7 cells and doxorubicin-resistant MCF-7/D0X cells. MIT was used to detect the proliferation of doxorubicin ( DOX)-treated groups. Flow cytometry was applied to detect the apoptotic rate of each group after transfection. Western blot was used to detect the expression of HMGB1 and autophagy-related proteins. Double Lucif-erase Report experiment was carried out to evaluate the targeting effect of miR-142-3p on HMGB1. Results The level of miR-142-3p in MCF-7/D0X cells was sig nificantly down-regulated. Overexpression of miR-142-3p enhanced the sensitivity of breast cancer cells to DOX and increased the apoptotic rate induced by DOX. HMGB1 was the direct functional target of miR-142-3p in breast cancer cells,and the overexpression of HMGB1 could significantly relieve the promotion of ap-optosis and inhibition of autophagy by miR-142-3p uP-regulation. Conclusions The overexpression of miR-142-3p may enhance the chemosensitivity of breast cancer cells to DOX by inhibiting autophagy and targeting HMGB1. miR-142-3p/HMGBl provides a new target for reversing the drug resistance of breast cancer.

YAP silencing reverses doxorubicin resistance in lung cancer cell line PC9 and its mechanism / 中国癌症杂志

Background and purpose:Drug resistance is a major cause of failure in lung cancer chemotherapy. This study aimed to investigate the effect of YAP on doxorubicin resistance in lung cancer and its underlying mechanism. Methods:Doxorubicin resistant lung cancer cell clones were established from parental sensitive cancer PC9 cell line via in vitroinduction, and the expression of YAP was analyzed. YAP was down-regulated via shRNA to different levels. MTS assay was employed to determine cell proliferation and drug sensitivity. Flow cytometry was used to determine cell cycle distribution, apoptosis and uptake of Rh-123. Western blot and quantitative real-time polymerase chain reaction (QRT-PCR) assay were used to determine the expression of ABCB1, ABCC1, p53, Runx2, ITGB2 and ErbB4. The phosphory-lation of serine/threonine kinase (AKT) was determined as well.Results:Doxorubicin resistant PC9/Adr cell clone was obtained with over-expressed YAP. Expression of YAP in PC9/Adr cells was down-regulated to different levels via shR-NA. After YAP silencing, cell proliferation was reduced, while sensitivity to doxorubicin was increased. The cell cycle was significantly halted by G0/G1 phase. Doxorubicin induced-apoptotic rate and cellular uptake of Rh-123 were increased,with positive correlation to YAP silencing level. Western blot and QRT-PCR results showed that after YAP silencing, ABCB1, ABCC1, Runx2, ITGB2, and ErbB4 proteins were down-regulated, while the expression of p53 was up-regulated. Phosphorylation of AKT was inhibited as well.Conclusion:Over-expression of YAP is involved in doxorubicin resistance in PC9/Adr cell line. Silencing of YAP could restore doxorubicin sensitivity. The mechanism involves regulation of drug resistance-related genes and promotion of apoptosis.

Anti-proliferative effect of salinomycin on doxorubicin-resistant human breast cancer MCF-7/DOX cells / 中国药理学通报

Aim To investigate the anti-proliferative effect of salinomycin on doxorubicin-resistant human breast cancer MCF-7 /DOX cells.Methods MCF-7 and MCF-7 /DOX cells were treated or untreated with salinomycin.Cell viability was detected by MTS assay. Cell apoptosis was detected by Annexin V-FITC /PI as-say.Reactive oxygen species (ROS)was measured by DCFH-DA staining.Mitochondrial membrane potential was measured by JC-1 assay.The expression of apopto-sis related proteins BAX, BCL-2, caspase-3, and caspase-9 were evaluated by Western blot analysis. Results The cell viability was significantly reduced by salinomycin treatment in a dose-dependent manner. The flow cytometry results showed that salinomycin in-duced MCF-7 /DOX cell apoptosis,increased ROS pro-duction,and decreased mitochondrial membrane poten-tial.Furthermore,salinomycin decreased the expres-sion of BCL-2,and increased the expression of BAX, cleaved caspase-3,and cleaved caspase-9.Moreover, the antioxidant N-acetylcysteine (NAC ) markedly blocked the above effects.Conclusions Our results suggest that salinomycin-induced apoptosis in MCF-7 /DOX is associated with induction of ROS production, and activation of mitochondria apoptosis pathway, which may become a potential chemotherapeutic agent for the therapy of doxorubicin resistant breast cancer.

Involvement of miR-30c in resistance to doxorubicin by regulating YWHAZ in breast cancer cells

MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.

Correlation of Early Systemic Recurrence with In Vitro Adenosine Triphosphate-Based Chemotherapy Response Assay in Stage II and III Breast Cancer Patients Treated with Doxorubicin-Based Chemotherapy / 한국유방암학회지

PURPOSE: An in vitro adenosine triphosphate-based chemotherapy response assay (ATP-CRA) was designed to require only a limited number of cells and shorten test turnaround time with a high success rate. This study investigated the correlation between in vitro doxorubicin sensitivity of tumor cells and early systemic recurrence, defined as recurrence within 2 years after surgery. METHODS: From January 2004 to March 2007, the ATP-CRA for doxorubicin was tested in 128 patients among breast cancer patients treated at Gangnam Severance Hospital, Seoul, Korea. The American Joint Committee on Cancer stages for all patients were II and III. All patients received doxorubicin-based chemotherapy. Selected patients were divided into a chemosensitive group and a non-chemosensitive group, according to a 40% cell death rate as a cut-off value. We analyzed the relationship between chemosensitivity and early systemic recurrence in patients with breast cancer. RESULTS: The mean age of the patients investigated was 44.6-years-old, the mean follow-up period was 39.9 months, and recurrence free survival was 38.6 months. Thirteen recurrences were observed during follow-up. Among 13 patients with a recurrence, eight had a recurrence within 2 years (early recurrence). All of the early recurring patients belonged to the non-sensitive group. Doxorubicin sensitivity results measured by ATP-CRA were related with early recurrence free survival in patients with breast cancer (p=0.030). The mean cell death rate derived from the ATP-CRA for the early recurrence group tended to be lower than that of the non-early recurrence group, but the difference was not statistically significant (p=0.05). CONCLUSION: Doxorubicin sensitivity measured by ATP-CRA was well correlated with in vivo drug responsibility to predict early recurrence against doxorubicin-based adjuvant chemotherapy in patients with breast cancer.

Isolation of Differentially-Displayed cDNAs from a Doxrubicin Resistant Gastric Carcinoma Cell Line / 대한암학회지

PURPOSE: This study was aimed to isolate cDNAs putatively associated with doxorubicin resistance or sensitivity in gastric carcinoma cell line. MATERIALS AND METHODS: A doxorubicin-sensitive parental SNU-16 and doxorubicin resistant SNU-16DOX cell line were used. Differential display-PCR(DD-PCR) was employed to screen for differentially expressed cDNA fragment either in parental or resistant cell line and followed by subtractive hybridization to discriminate true positive from false positive clones. The sequences were determined and compared to the sequence data base registered at the GenBank. RESULTS: Four clones(16, 19, 21, and 22 clone) were isolated, of which three(16, 19 and 21 clone) was downexpressed, and one(22 clone) was overexpressed in doxorubicin resistant cell line. All four clones were found to be novel sequences. Further analysis for these clones are under characterization. CONCLUSION: Four partial cDNA clones that are putatively associated with doxorubicin resistance or sensitivity in gastric carcinoma cell line were isolated.