Modulation of protein expression levels and DNA methylation status of breast cancer metastasis genes by anthracycline-based chemotherapy and the demethylating agent decitabine

Abstract

Epigenetic drugs are promising add-ons to cancer treatment; still, adverse effects concerning tumour promotion have been reported occasionally. In this in vitro study, we investigated the effect of combination treatment of decitabine with anthracycline-based chemotherapy [5-fluorouracil plus epirubicine plus cyclophosphamide (FEC)] on viability and metastatic activity of breast cancer cell lines, MDA-MB-231 (estrogen receptor-negative) and MCF-7 (estrogen receptor-positive). The effect of decitabine and its combined treatment with FEC on viability of both cancer cell lines was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide and adenosine triphosphate (ATP) cell survival assays. DNA methylation specific real-time polymerase chain reaction (PCR) (Methylight®) was employed to document the methylation status of the metastasis-relevant urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-I (PAI-1) genes. Additionally, protein expression levels of uPA and PAI-1 were determined using enzyme-linked immunosorbent assays. Invasion capacity of cells was assayed using Matrigel® invasion assay. Decitabine lowered the viability of MCF-7 cells, although MDA-MB-231 cells were not affected. Decitabine did not augment FEC-mediated cytotoxicity in both cell lines. In MCF-7 cells, methylation of the uPA and PAI-1 gene promoter was significantly reduced by decitabine or decitabine plus FEC. Protein levels of uPA and PAI-1 were induced by all treatments. Decitabine significantly induced the invasion capacity of MCF-7 cells, whereas all of the drugs resulted in decreased invasion capacity of MDA-MB-231. Our results suggest differential effects of single-dose decitabine and its combination with FEC on the metastatic capacity and survival of breast cancer cell lines endowed with different metastatic behaviour.

Epigenetic regulation of glycosylation and the impact on chemo-resistance in breast and ovarian cancer

“…This suggests that in the MDA-MB-231 cells the apparent reduction in viability may be due to necrosis because of impaired apoptotic pathway(a). 86…”

Epigenetic changes associated with inflammation in breast cancer patients treated with chemotherapy

“…One possibility is that cancer or its treatment leads to epigenetic changes that predispose to chronic inflammation. Epigenetic alterations as a consequence of multiple chemotherapy regimens have been reported in numerous genes in DNA samples extracted from both breast cancer and peripheral blood cells (Ari et al, 2011; Avraham et al, 2012; Sharma et al, 2012; Swisher et al, 2009). However, the impact of chemotherapy-induced epigenetic changes has not been related to systemic inflammation and/or behavior.…”

Changes in Gene Methylation Following Chemotherapy in Breast Cancer Cell Lines

“…We found that in cells treated with decitabine, FEC, and the combination regimens, DAPK as well as TMS1 were significantly demethylated in the respective cell lines in a synergistic fashion. In addition, our previously data demonstrate that decitabine plus FEC treatments increased apoptosis than decitabine or FEC treatment alone in MCF-7 cells [38], which may be a result of reactivation of gene expression by promoter demethylation.…”

“…In our previous study, we show that the treatment of MCF-7 and MDA-MB-231 cells with FEC significantly reduced cell viability in a dose-dependent manner. However, the combination of the different doses of FEC with 10 µM decitabine did not impair cell viability levels any further [38].…”