CDC25A (Phospho-Ser75) ELISA Kit

To elucidate the molecular mechanisms of tamoxifen resistance in breast cancer, we performed gene array analyses and identified 366 genes with altered expression in four unique tamoxifen-resistant (TamR) cell lines vs the parental tamoxifen-sensitive MCF-7/S0.5 cell line. Most of these genes were functionally linked to cell proliferation, death and control of gene expression, and include FYN, PRKCA, ITPR1, DPYD, DACH1, LYN, GBP1 and PRLR. Treatment with FYN-specific small interfering RNA or a SRC family kinase inhibitor reduced cell growth of TamR cell lines while exerting no significant effect on MCF-7/S0.5 cells. Moreover, overexpression of FYN in parental tamoxifen-sensitive MCF-7/S0.5 cells resulted in reduced sensitivity to tamoxifen treatment, whereas knockdown of FYN in the FYN-overexpressing MCF-7/S0.5 cells restored sensitivity to tamoxifen, demonstrating growth-and survival-promoting function of FYN in MCF-7 cells. FYN knockdown in TamR cells led to reduced phosphorylation of 14-3-3 and Cdc25A, suggesting that FYN, by activation of important cell cycle-associated proteins, may overcome the anti-proliferative effects of tamoxifen. Evaluation of the subcellular localization of FYN in primary breast tumors from two cohorts of endocrine-treated ER+ breast cancer patients, one with advanced disease (N = 47) and the other with early disease (N = 76), showed that in the former, plasma membrane-associated FYN expression strongly correlated with longer progression-free survival (P < 0.0002). Similarly, in early breast cancer patients, membrane-associated expression of FYN in the primary breast tumor was significantly associated with increased metastasis-free (P < 0.04) and overall (P < 0.004) survival independent of tumor size, grade or lymph node status. Our results indicate that FYN has an important role in tamoxifen resistance, and its subcellular localization in breast tumor cells may be an important novel biomarker of response to endocrine therapy in breast cancer.

Zearalenone (ZEA), an estrogen-like mycotoxin, is commonly detected in animal feeds including improperly stored grains. It has been well demonstrated that ovarian granulosa cells (GCs) perform vital roles during follicular development, however, the competing endogenous RNA (ceRNA) network in GCs after ZEA exposure remains to be well described. Here, for the first time, we adopted whole-transcriptome sequence technology to explore the molecular mechanism of ZEA toxicology on porcine GCs. The results provide evidence that the cell cycle of porcine GCs is arrested in the G2/M phase after exposure to ZEA. Furthermore, bioinformation analysis found that cell cycle arrest related genes were perturbed, including CDK1, CCNB1, CDC25A, and CDC25C, which was consistent with the results of RTqPCR, immunofluorescence, and Western Blotting. Based on the whole-transcriptome sequence data, by constructing ceRNA networks related to cell cycle arrest, we observed that ZEA exposure arrested cell cycle progression at the G2/M phase in porcine GCs, and non-coding RNAs (ncRNAs) played an important role in this process via regulating the expressions of cell cycle arrest related genes. Taken together, our data here provides strong data to support that the toxicological mechanism regarding the widely distributed toxicant ZEA acts through ceRNA networks in porcine granulosa cells. (C) 2020 Elsevier Ltd. All rights reserved.