Preexposure of MCF-7 breast cancer cell line to dexamethasone alters the cytotoxic effect of paclitaxel but not 5-fluorouracil or epirubicin chemotherapy

Abstract

PurposeGlucocorticoids (GCs) are often administered prior to any chemotherapeutics to prevent the secondary effects of anticancer agents. Glucocorticoid receptors (GRs) are expressed in several types of cancer cells, particularly in several histological types of breast cancer. Activation of GRs is not associated with any specific cellular response. Both proapoptotic and antiapoptotic responses have been observed, depending on the study or the type of breast cancer cells. Therefore, it is of relevance to investigate the possible modulation of apoptotic effect of chemotherapeutic agents when cancerous cells have previously been exposed to GCs.MethodsIn vitro cell growth was assayed by counting MCF-7 cells upon exposure to epirubicin (25 nM), 5-fluorouracil (5-FU) (15 µM), and paclitaxel (15 nM), either with or without prior exposure to the GC dexamethasone (Dex) (100 nM).ResultsFollowing preexposure to Dex, the antiapoptotic activity of paclitaxel was significantly reduced by 8.5% (p<0.05), but the activities of epirubicin and 5-FU remained unaltered.ConclusionIn light of the finding that the response of MCF-7 cells pretreated with Dex was significantly reduced, we recommend that the function of GCs should be defined more precisely if they are to be used in conjunction with chemotherapy.

Glucocorticoid-dependent expression of IAP participates in the protection against TNF-mediated cytotoxicity in MCF7 cells

“…GCs are the most common antiemetics and are administered shortly before chemotherapy to counteract the secondary effects of chemotherapy [6]. In the case of MCF7 cells that represent luminal A breast cancer, in vitro evidence suggests that GCs inhibit the effect of paclitaxel [47]. Nevertheless, GCs alone have anticancer effects, such as inhibiting angiogenesis in vitro [48] and cell proliferation [49]; the latter effect was recently associated with the capacity of cells to re-establish the expression of clock genes such as BMAL [50], although this has yet to be proven in the case of breast cancer cells.…”

Dexamethasone Promotes Aspergillus fumigatus Growth in Macrophages by Triggering M2 Repolarization via Targeting PKM2

“…Corticosteroids are crucial hormones endogenously produced by the adrenal glands to regulate essential inflammation-related processes [18,19], but their main function is to maintain homeostasis [20]. Corticosteroids can impinge on a variety of metabolic, reproductive, and developmental processes [21].…”