Effects of Rapamycin on Cell Apoptosis in MCF-7 Human Breast Cancer Cells

Abstract

Background: Rapamycin is an effective anti-angiogenic drug. However, the mode of its action remains unclear. Therefore, in this study, we aimed to elucidate the antitumor mechanism of rapamycin, hypothetically via apoptotic promotion, using MCF-7 breast cancer cells. Materials and Methods: MCF-7 cells were plated at a density of 1510 5 cells/well in 6-well plates. After 24h, cells were treated with a series of concentrations of rapamycin while only adding DMEM medium with PEG for the control regiment and grown at 37 o C, 5% CO 2 and 95% air for 72h. Trypan blue was used to determine the cell viability and proliferation. Untreated and rapamycin-treated MCF-7 cells were also examined for morphological changes with an inverted-phase contrast microscope. Alteration in cell morphology was ascertained, along with a stage in the cell cycle and proliferation. In addition, cytotoxicity testing was performed using normal mouse breast mammary pads. Results: Our results clearly showed that rapamycin exhibited inhibitory activity on MCF-7 cell lines. The IC 50 value of rapamycin on the MCF-7 cells was determined as 0.4µg/ml (p<0.05). Direct observation by inverted microscopy demonstrated that the MCF-7 cells treated with rapamycin showed characteristic features of apoptosis including cell shrinkage, vascularization and autophagy. Cells underwent early apoptosis up to 24% after 72h. Analysis of the cell cycle showed an increase in the G0G1 phase cell population and a corresponding decrease in the S and G2M phase populations, from 81.5% to 91.3% and 17.3% to 7.9%, respectively. Conclusions: This study demonstrated that rapamycin may potentially act as an anti-cancer agent via the inhibition of growth with some morphological changes of the MCF-7 cancer cells, arrest cell cycle progression at G0/G1 phase and induction of apoptosis in late stage of apoptosis. Further studies are needed to further characterize the mode of action of rapamycin as an anti-cancer agent.

The Effect of Rapamycin on Oxidative Stress in MCF-7 and MDA MB-231 Human Breast Cancer Cell Lines

“…Another review obviously demonstrated that rapamycin exhibited inhibitory activity on the MCF-7 cell lines. Direct visualization via inverted microscopy revealed that the MCF-7 cell lines that were cured with ra-pamycin exhibited the properties of apoptosis as well as autophagy, vascularization, and cell shrinkage (22).…”

Monitoring Early Breast Cancer Response to Neoadjuvant Therapy Using H‐Scan Ultrasound Imaging: Preliminary Preclinical Results

“…It is worth noting that there was a significant linear correlation between the predominance of the blue hue found in the H‐scan ultrasound images and mean intratumoral apoptotic activity ( R 2 > 0.40, P < .04) in animals administered a single dose of chemotherapy. Given that paclitaxel is a class of chemotherapeutics that inhibits cellular mitosis leading to apoptosis, we theorize that the progressive color map shift observed in the longitudinal H‐scan ultrasound images is, in fact, detection of cancer cell shrinkage in the whole tumor mass as the cells undergo apoptotic death …”

“…Characteristic of solid tumors after treatment, this process involves a sequence of intracellular events that systematically dismantle the cell. The first observable change in a cancer cell undergoing apoptosis is physical shrinkage . Drug resistance often prevents cancer cells from undergoing sufficient levels of apoptosis, resulting in cell survival and treatment failure .…”

Aldose Reductase Inhibitor Fidarestat as a Promising Drug Targeting Autophagy in Colorectal Carcinoma: a Pilot Study

“…These preliminary findings strongly suggested the role of GD-triggered autophagy in my study. Moreover, cell death-related research in the past decade has substantially enhanced my current understanding of non-apoptotic programmed cell death events, primarily lysosomal-mediated cell death, necroptosis and autophagy (Amravadi, 2009;Tengku Din et al, 2014) and the complex cross-talk among diverse components of each of these cell death pathways further regulates subsequent cancer progression under stressed/physiologically altered conditions.…”