Depletion of membrane cholesterol compromised caspase-8 imparts in autophagy induction and inhibition of cell migration in cancer cells

Abstract

BackgroundCholesterol in lipid raft plays crucial role on cancer cell survival during metastasis of cancer cells. Cancer cells are reported to enrich cholesterol in lipid raft which make them more susceptible to cell death after cholesterol depletion than normal cells. Methyl-β-cyclodextrin (MβCD), an amphipathic polysaccharide known to deplete the membrane cholesterol, induces cell death selectively in cancer cells. Present work was designed to identify the major form of programmed cell death in membrane cholesterol depleted cancer cells (MDA-MB 231 and 4T1) and its impact on migration efficiency of cancer cells.MethodsMembrane cholesterol alteration and morphological changes in 4T1 and MDA-MB 231 cancer cells by MβCD were measured by fluorescent microscopy. Cell death and cell proliferation were observed by PI, AO/EB and MTT assay respectively. Programme cell death was confirmed by flow cytometer. Caspase activation was assessed by MTT and PI after treatments with Z-VAD [OME]-FMK, mitomycin c and cycloheximide. Necroptosis, autophagy, pyroptosis and paraptosis were examined by cell proliferation assay and flow cytometry. Relative quantitation of mRNA of caspase-8, necroptosis and autophagy genes were performed. Migration efficiency of cancer cells were determined by wound healing assay.ResultsWe found caspase independent cell death in cholesterol depleted MDA-MB 231 cells which was reduced by (3-MA) an autophagy inhibitor. Membrane cholesterol depletion neither induces necroptosis, paraptosis nor pyroptosis in MDA-MB 231 cells. Subsequent activation of caspase-8 after co-incubation of mitomycin c and cycloheximide separately, restored the cell viability in cholesterol depleted MDA-MB 231 cells. Down regulation of caspase-8 mRNA in cholesterol depleted cancer cells ensures that caspase-8 indirectly promotes the induction of autophagy. In another experiment we have demonstrated that membrane cholesterol depletion reduces the migration efficiency in cancer cells.ConclusionTogether our experimental data suggests that membrane cholesterol is the crucial for the recruitment and activation of caspase-8 as well as its non-apoptotic functions in cancer cells. Enriched cholesterol in lipid raft of cancer cells may be regulating the cross talk between caspase-8 and autophagy machineries to promote their survival and migration. Therefore it can be explored to understand and address the issues of chemotherapeutic and drugs resistance.Electronic supplementary materialThe online version of this article (10.1186/s12935-018-0520-4) contains supplementary material, which is available to authorized users.

Surface cholesterol-enriched domains specifically promote invasion of breast cancer cell lines by controlling invadopodia and extracellular matrix degradation

“…The contribution of chol in cell migration/invasion is not new but data are often contradictory. Indeed, chol depletion has been shown to reduce breast cancer cell lines migration [ 53 , 54 ] while its supplementation promotes migration and invasion of renal carcinoma cells [ 55 ]. Conversely, lower membrane chol content correlates with increased invading capacity compared to non-invading cells [ 13 , 19 ].…”

Pyroptosis-Related Signature and Tumor Microenvironment Infiltration Characterization in Head and Neck Squamous Cell Carcinoma

“…Caspase‐8 can directly cleave caspase‐3 to activate apoptosis or GSDMD to trigger pyroptosis, as well as also cleaving RIPK1 and RIPK3 to inhibit necroptosis ( Orning and Lien, 2021 ). Moreover, membrane cholesterol is essential for the activation and recruitment of caspase-8 and its non-apoptotic functions in cancer cells ( Kumar et al, 2018 ). Until now, there is no related study about the role of CASP8 in HNSCC, and our analysis can provide useful information for the in-depth exploration.…”

Targeting cellular cholesterol for anticancer therapy

“…Alternatively, disruption of lipid raft microdomains has been foreseen as a rational therapeutic strategy in cancer treatment, more so for ER+ BCs that contain high amounts of cholesterol. Accumulating evidence has shown that the depletion of cholesterol from lipid rafts augments apoptosis thereby reducing carcinogenesis . Moreover, lipid raft disruption induces chemosensitivity as well as increases sensitivity to certain drugs such as tamoxifen .…”