Antiproliferative and Apoptotic Effects of Tempol, Methotrexate, and Their Combinations on the MCF7 Breast Cancer Cell Line

Abstract

Breast cancer holds the top position among the cancers occurring in women. Despite the utilization of surgical removal, chemotherapy, and radiation therapy, there is currently no conclusive treatment available to prevent breast cancer. New treatment approaches are being studied since traditional chemotherapeutics also damage healthy cells. Tempol (TPL) is a potent antioxidant agent that has been shown to exhibit anticancer activity. The objective of this research was to examine the impacts on cell proliferation and apoptosis by using methotrexate (MTX) and TPL individually and in combination on MCF7 breast cancer cells. MCF7 cells were exposed to TPL, MTX, and MTX + TPL for 48 h. The effects of the administered drugs on cell viability were determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Enzyme-linked immunosorbent assay analysis was conducted to assess the levels of the antiapoptotic protein Bcl-2, the pro-apoptotic protein Bax, and the activity of caspase-3 in MCF7 cells. Increasing concentrations of TPL and MTX significantly decreased the proliferation in MCF7 cells in both solo and combined use. Solo and combined use of TPL and MTX significantly increased caspase-3 activity and Bax levels and significantly decreased Bcl-2 levels in the cells. This study revealed that the solo use of TPL and MTX inhibited proliferation and increased apoptotic activity in the cells. In addition, TPL increased the antiproliferative and apoptosis efficiency of MTX on cancer cells as a result of the combined use of these drugs.

Figure 1

Viability levels in MCF7 cells following the administration of increasing doses of MTX. [n = 7, mean ± standard error of mean (SEM)] (*P < 0.05, when the cell viability is compared with that of the control).

Figure 2

Viability levels in MCF7 cells following the administration of increasing doses of TPL. (n = 7, mean ± SEM) (*P < 0.05, when the cell viability is compared with that of the control).

Figure 3

Viability levels in MCF7 cells following the administration of MTX, TPL, and MTX + TPL. (n = 7, mean ± SEM) (*P < 0.05, when the cell viability is compared with that of the control).

Figure 4

Effect of MTX and TPL on caspase-3, Bax, and Bcl-2 expressions in MCF7 cells. (n = 7, mean ± SEM) (*P < 0.05, when the expression levels are compared with that of the control; #P < 0.05, when the expression levels are compared with that of the control and other groups).