Protective role of statins during anticoagulation for venous thromboembolism: beyond their lipid lowering effect?

Statins Effects on Blood Clotting: A Review

Statins are powerful lipid-lowering drugs that inhibit cholesterol biosynthesis via downregulation of hydroxymethylglutaryl coenzyme-A reductase, which are largely used in patients with or at risk of cardiovascular disease. Available data on thromboembolic disease include primary and secondary prevention as well as bleeding and mortality rates in statin users during anticoagulation for VTE. Experimental studies indicate that statins alter blood clotting at various levels. Statins produce anticoagulant effects via downregulation of tissue factor expression and enhanced endothelial thrombomodulin expression resulting in reduced thrombin generation. Statins impair fibrinogen cleavage and reduce thrombin generation. A reduction of factor V and factor XIII activation has been observed in patients treated with statins. It is postulated that the mechanisms involved are downregulation of factor V and activated factor V, modulation of the protein C pathway and alteration of the tissue factor pathway inhibitor. Clinical and experimental studies have shown that statins exert antiplatelet effects through early and delayed inhibition of platelet activation, adhesion and aggregation. It has been postulated that statin-induced anticoagulant effects can explain, at least partially, a reduction in primary and secondary VTE and death. Evidence supporting the use of statins for prevention of arterial thrombosis-related cardiovascular events is robust, but their role in VTE remains to be further elucidated. In this review, we present biological evidence and experimental data supporting the ability of statins to directly interfere with the clotting system.

Atorvastatin induces downregulation of matrix metalloproteinase-2/9 in MDA-MB-231 triple negative breast cancer cells

Matrix metalloproteinases (MMPs) are a family of endopeptidases, mainly responsible of extracellular tissue remodeling. Abundant expression of MMPs leads to a number of tumorigenic processes including proliferation, angiogenesis, metastasis and invasion. Therefore, suppressing MMP expression is particularly important in cancer. Atorvastatin is a member of statin family, with cholesterol-lowering properties. Recently, it has emerged as a potential anticancer agent. Multiple researchers have reported promising results of atorvastatin use in cancer therapies. However, its effect on the expression of matrix metalloproteinases in breast cancer is unknown. In the present study, we have confirmed the apoptotic activity of atorvastatin on highly metastatic MDA-MB-231 triple negative breast cancer cells and investigated the gene expression of MMP-2/9. In this regard, MTT analysis was performed to evaluate cytotoxicity. Apoptotic activity was assessed by Annexin V binding and multicaspase assays. Western blot analysis was used to detect the apoptosis-related proteins. RT-PCR analysis was performed to evaluate the mRNA expression levels of MMP-2/9. Results indicated that atorvastatin reduces cell viability significantly at 5 µM after 48 h of treatment (p < 0.0001). It also induces caspase-dependent apoptosis, alters the expression of Bax and Bcl-2 in favour of apoptosis and stimulates cell cycle arrest at S phase (p < 0.05). Moreover, atorvastatin downregulates the mRNA expression of MMP-2 and MMP-9 significantly (p < 0.05). In conclusion, these results demonstrate for the first time that atorvastatin inhibits MMP-2 and MMP-9 gene expression in MDA-MB-231 cells, in addition to inducing caspase-dependent apoptosis.