Simvastatin induced actin cytoskeleton disassembly in normal and transformed fibroblasts without affecting lipid raft integrity

Abstract

Statins are the most commonly prescribed agents used to modulate cholesterol levels in course of hypercholesterolemia treatment because of their relative tolerability and LDL-C lowering effect. Recently, there are emerging interests in the perspectives of statin drugs as anticancer agents based on preclinical evidence of their antiproliferative, proapoptotic, and anti-invasive properties. Functional impact of statin application on transformed cells still remains obscure that requires systematic study on adequate cellular models to provide correct comparison with their non-transformed counterparts. Cholesterol is the major lipid component of mammalian cells and it plays a crucial role in organization, lateral heterogeneity, and dynamics of plasma membrane as well as in membrane-cytoskeleton interrelations. To date, it is uncertain whether cellular effects of statins involve lipid-dependent alteration of plasma membrane. Here, the effects of simvastatin on lipid rafts, F-actin network and cellular viability were determined in comparative experiments on transformed fibroblasts and their non-transformed counterpart. GM1 lipid raft marker staining indicated no change of lipid raft integrity after short- or long-term simvastatin treatments. In the same time, simvastatin induced cytoskeleton rearrangement including partial F-actin disruption in cholesterol- and lipid raft-independent manner. Simvastatin dose-dependently affected viability of BALB/3T3 and 3T3B-SV40 cell lines: transformed fibroblasts were noticeably more sensitive to simvastatin comparing to non-transformed cells.

Network analysis reveals the molecular bases of statin pleiotropy that vary with genetic background

“…We propose that statin treatment induces the UPR, dysregulates endocytosis and causes autophagic cell death (Fig 12). It is plausible that all of these phenotypes have a role in the anticancer activity of atorvastatin via induction of UPR, especially since statins inhibit and remodel actin cytoskeleton (Boerma et al 2008; Chubinskiy-Nadezhdin et al 2017), actin is necessary for endocytosis (Mooren et al 2012), and UPR is induced in yeast mutants deficient of actin-mediated steps in endocytosis (Mattiazzi Usaj et al 2020). The many genetic interactions involving these cellular processes described here potentially provide lists for drug targets.…”

Inhibiting Airway Smooth Muscle Contraction Using Pitavastatin: A Role for the Mevalonate Pathway in Regulating Cytoskeletal Proteins

“…HMGCR is the rate-limiting enzyme of sterol biosynthesis in the mevalonate (MA) pathway. Supporting the relevance of this pathway are adjacent studies in endothelial cells, saphenous vein smooth muscle cells, and fibroblasts, that have revealed that lipophilic statins can inhibit the RhoA/ROCK pathway (Turner et al, 2005), MLC phosphorylation (Lampi et al, 2016), and F-actin levels (Farina et al, 2002;Chubinskiy-Nadezhdin et al, 2017). Although similar effects have never been directly reported in ASM, our previous work performed using a murine model of acute allergic airway inflammation has noted that some inhaled statins can reduce airway resistance and airway hyper-responsiveness (AHR), including airway hypersensitivity (Xu et al, 2012;Zeki et al, 2015;Wu et al, 2017).…”

Influence of ClearT and ClearT2 Agitation Conditions in the Fluorescence Imaging of 3D Spheroids

“…The imaging penetration depth of the PI, i.e., how deep in the Z-axis it is possible to acquire PI fluorescence signal (please see Figure 4A), was calculated by multiplying the number of stacks with PI fluorescence (stacks with fluorescence intensity in the spheroids area higher than the fluorescence intensity of the background) by the thickness of the stack (5 µm) [39,40]. Lastly, to determine the PI cross-section imaging depth that translates the PI fluorescence inside the spheroid, it was counted the number of pixels with fluorescence in the spheroid area at 25, 50, 75 and 100 µm of depth in the Z-axis (please see Figure 4D) [41,42]. To accomplish that, the gray value of each pixel in the spheroid area was determined (gray value equal to zero corresponds to pixels with no PI fluorescence; gray value higher than 0 corresponds to pixels with PI fluorescence) [41,42].…”

“…Lastly, to determine the PI cross-section imaging depth that translates the PI fluorescence inside the spheroid, it was counted the number of pixels with fluorescence in the spheroid area at 25, 50, 75 and 100 µm of depth in the Z-axis (please see Figure 4D) [41,42]. To accomplish that, the gray value of each pixel in the spheroid area was determined (gray value equal to zero corresponds to pixels with no PI fluorescence; gray value higher than 0 corresponds to pixels with PI fluorescence) [41,42].…”

“…Therefore, the cross-section imaging depth in the PI-stained spheroids subjected to Clear T and Clear T2 methods was performed to determine the best incubation conditions. For that purpose, the number of pixels with PI signal inside the spheroids at different depths in Z-axis (25, 50, 75 and 100 µm) was measured [41,42]-Figure 4D.…”