RETRACTED: The Enhanced Cytotoxic and Pro-Apoptotic Effects of Optimized Simvastatin-Loaded Emulsomes on MCF-7 Breast Cancer Cells

Abstract

Statins, including simvastatin (SMV), are commonly used for the control of hyperlipidaemia and have also proven therapeutic and preventative effects in cardiovascular diseases. Besides that, there is an emerging interest in their use as antineoplastic drugs as demonstrated by different studies showing their cytotoxic activity against different cancer cells. In this study, SMV-loaded emulsomes (SMV-EMLs) were formulated and evaluated for their cytotoxic activity in MCF-7 breast cancer cells. The emulsomes were prepared using a modified thin-film hydration technique. A Box–Behnken model was used to investigate the impact of formulation conditions on vesicle size and drug entrapment. The optimized formulation showed a spherical shape with a vesicle size of 112.42 ± 2.1 nm and an entrapment efficiency of 94.34 ± 1.11%. Assessment of cytotoxic activities indicated that the optimized SMV-EMLs formula exhibited significantly lower half maximal inhibitory concentration (IC50) against MCF-7 cells. Cell cycle analysis indicated the accumulation of cells in the G2-M phase as well as increased cell fraction in the pre-G1 phase, suggesting an enhancement of anti-apoptotic activity of SMV. The staining of cells with Annex V revealed an increase in early and late apoptosis, in line with the increased cellular content of caspase-3 and Bax. In addition, the mitochondrial membrane potential (MMP) was significantly decreased. In conclusion, SMV-EMLs demonstrated superior cell death-inducing activity against MCF-7 cells compared to pure SMV. This is mediated, at least in part, by enhanced pro-apoptotic activity and MMP modulation of SMV.

The Encapsulation of Febuxostat into Emulsomes Strongly Enhances the Cytotoxic Potential of the Drug on HCT 116 Colon Cancer Cells

“…As showed in Figure 4 , the IC50 of FBX-R (21.4 ± 3.0 µM) was significantly decreased by the encapsulation of the drug into the EMLs (5.4 ± 3.1 µM, about 4-fold lower), underlining the enhanced therapeutic potential of the optimized formulation in counteracting cancer cells proliferation. These results are in agreement with recent data showing the ability of EMLs-based formulations to enhance the cytotoxic effects of another “repositioned drug” (simvastatin) on breast cancer cells [ 33 ]. Taking into consideration the frequently reported adverse events related to the use of this drug [ 46 ], the development of new formulations able to boost its therapeutic effect, reducing the effective dose of FBX could be of great relevance for future translational studies in cancer patients.…”

“…Febuxostat (FBX) is an inhibitor of xanthine oxidase enzyme currently used for the treatment of hyperuricemia in subjects with gout [ 35 ]. It has been shown that this drug is practically insoluble in water, while its solubility increases in solvents such as dimethylsulfoxide [ 36 ], and the use of drug delivery systems such as EMLs [ 33 , 37 ] could represent a powerful tool to increase its solubility and, at the same time, improve the drug dissolution rate, then enhancing the clinical efficacy of this drug.…”

“…As a last step, the ability of the free or EMLs-encapsulated drug to modulate the MMP, representing a well-known index of cell suffering and death, in our human colorectal cancer cell model was tested. Despite the well-demonstrated resistance of cancer cells to MMP-induced changes [ 33 , 50 , 51 ], both FBX-R and FBX-EMLs treatments were able to significantly decrease the MMP (%) in HCT 116 cells ( Figure 8 ). Of note, the ability of the free drug to decrease the MMP (%) was greatly enhanced (from −14.6 to −35.7%, about 2.4-fold stronger) when FBX was delivered in the presence of EMLs.…”

“…The IC50 values of HCT 116 colorectal carcinoma cells left untreated (control) or treated with Blank EMLs, pure FBX (FBX-R), or FBX-loaded EMLs (FBX-EMLs) for 24 h, were measured by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay as previously described [ 32 , 33 ]. Briefly, the cell suspension (2 × 10 5 cells) was seeded into a 96-well tissue culture plate and incubated in a humidified environment (5% CO 2 , 37 °C) to allow the complete cell attachment.…”

“…The changes in MMP occurring in HCT 116 cells, previously seeded in 96-well plates (1 × 10 5 cells/well), left untreated (control) or treated with 2.1 µM of Blank EMLs, FBX-R, or FBX-EMLs for 24 h, were monitored by using a MitoProbe™ TMRM Assay Kit for Flow Cytometry as previously described [ 33 ].…”