Elsevier

World Neurosurgery

Volume 165, September 2022, Pages e12-e21
World Neurosurgery

Original Article
Simvastatin Inhibits Tumor Growth and Migration by Mediating Caspase-1–Dependent Pyroptosis in Glioblastoma Multiforme

https://doi.org/10.1016/j.wneu.2022.03.089Get rights and content

Abstract

Objectives

Glioblastoma multiforme (GBM) is the most common and lethal central nervous system cancer and is associated with a poor prognosis. Simvastatin, a kind of widely used hypolipidemic agent, has been investigated for its beneficial effects on various types of cancers. The main purpose of this paper is to investigate the potential inhibitory effects of simvastatin on GBM and the underlying mechanism.

Methods

Cell viability and cell cycle of simvastatin-treated U87 and U251 cells were determined by CCK8 assay and flow cytometry, respectively. Additionally, we assessed cell migration and invasion abilities using a wound-healing assay and transwell assay. mRNA and protein expression patterns of caspase-1 and its markers nucleotide-binding oligomerization domain-like receptor pyrin domain–containing 3 (NLRP3) and IL-1β in different conditions were detected by real-time polymerase chain reaction, immunofluorescence staining, and Western blot.

Results

Simvastatin decreased the viability of GBM cells and inhibited cell migration and invasion in a dose-dependent manner. Moreover, suppression of pyroptosis, as characterized by decreased expression of caspase-1, NLRP3, and IL-1β, was observed. However, use of an miR-214 inhibitor reversed the simvastatin suppressive effect on GBM cells.

Conclusions

Simvastatin inhibits GBM progression by suppressing caspase-1–dependent pyroptosis, regulated by miR-214.

Introduction

Glioblastoma multiforme (GBM) is the most common cerebral malignancy in adults and has the highest mortality and morbidity among all central nervous system cancers. Despite great advances in surgery, chemotherapy, radiotherapy, immunotherapy, and targeted therapy, patients' prognosis is far from satisfactory. Even comprehensive treatment cannot significantly reduce the risk of recurrence, progression, or death from GBM. Therefore, there is an urgent need to better understand the biological behavior of GBM and explore other potential adjuvant therapies. Statins, synthetic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, are widely used in the clinical treatment of high blood cholesterol. Beyond their cholesterol-lowering properties, results from previous in vivo and in vitro studies verify statin-dependent anti-inflammatory effects,1,2 and such responses are associated with the remodeling process during atheromatic plaque stabilization.3 However, this inhibitory effect is independent of the cholesterol-reducing properties of statins.4 In addition to these properties, numerous experimental and clinical studies have unexpectedly demonstrated the antitumor effect of statins by inducing suppression of malignant cells5 or inducing apoptosis.4,6 Statins have been investigated for their beneficial effects on various types of cancer, including the carcinoma of the colon and rectum, liver, breast, skin, prostate, and lung.7, 8, 9, 10

Pyroptosis is a type of programmed cell death and is thought of as a regulated form of necrosis.11 Unlike apoptosis, pyroptosis is initiated by the binding of NOD-like receptors (NLRs) to pathogen-associated molecular patterns and danger-associated molecular patterns,12,13 which generate active caspase-1, leading to pore formation in the membrane and enzymolysis of the precursors for inflammatory cytokines IL-1β and IL-18. Pyroptosis results in cell swelling, cell lysis, release of cytosolic contents such as lactate dehydrogenase, and induction of the inflammatory cytokines IL-1β and IL-18.14, 15, 16 Accumulating evidence suggests that pyroptosis is involved in a variety of diseases, such as diabetic cardiomyopathy,17 alcoholic gastritis,18 hepatocellular carcinoma, gastric cancer,14 non–small-cell lung cancer,10 and oral squamous cell carcinoma.19 Moreover, earlier findings by our group confirmed that pyroptosis is involved in proliferation and migration in GBM cells.20 Considering the potential connection between statin, pyroptosis, inflammation, and tumors, we hypothesize that statins may exert antitumor efficiency by mediating pyroptosis in GBM.

Our previous work has demonstrated that pyroptosis is activated in GBM20 and miR-214-3p directly targets caspase-1, through which miR-214-3p inhibits cellular proliferation and migration in glioma cells. In the present study, we observed that simvastatin suppresses the proliferation, migration, and invasion of GBM cell lines by regulating caspase-1–dependent pyroptosis. Additionally, si-miR-214-3p reversed simvastatin's inhibitory effect. These findings reveal another antitumor mechanism of statin and identify a potential therapeutic target to treat GBM.

Section snippets

Cell Culture

U87 and U251 human glioma cell lines were purchased from the iCell (Shanghai, China). U87 and U251 cells were maintained in dulbecco's modified eagle medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 100 U/mL penicillin, and 50 μg/mL streptomycin at 37°C in a humidified atmosphere of 5% CO2.

Cell Viability Analysis by CCK8 Assay

The viability of U87 and U251 cells in different conditions was determined by measuring cellular metabolism using 96-well plates. Briefly, 1 × 104 U87 and U251 cells in 200 μL of 10% FBS medium

Simvastatin Suppressed GBM Cell Viability

Simvastatin (Figure 1A) is one of the most widely used statin drugs in clinical treatment. First, we explore the effects of simvastatin on U87 and U251 cells. As shown in Figure 2A, we examined cell viability through CCK8 assay in response to treatment with different concentrations of simvastatin (0.5 μM, 1 μM, 2 μM, 4 μM, and 8 μM) at different time points (24 hours, 48 hours, and 72 hours). Our results showed that from 1 μM concentration of simvastatin, a significant dose-time inhibition

Discussion

Statin drugs have been widely used to treat hypercholesterolemia in the past 2 decades and have made a significant contribution to decreased cardiovascular morbidity and mortality.21 Beyond their cardioprotective effects, however, statins have been reported to have possible benefits regarding immunomodulation in organ transplantation and autoimmune diseases, induction of bone marrow stimulation, and suppression of cancer progression.22,23 A number of studies have prompted clinical trials

CRediT authorship contribution statement

Shulong Yang: Conceptualization, Methodology, Writing – original draft. Chuncheng Xie: Conceptualization, Data curation, Supervision. Tieyun Guo: Visualization, Investigation. Huiying Li: Formal analysis, Visulization. Nannan Li: Data curation, Software, Validation. Song Zhou: Formal analysis, Visualization. Xiuyun Wang: Writing – review & editing.

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    Conflict of interest statement: This work was supported by Heilongjiang Education Department Project (12541469).

    Shulong Yang and Chuncheng Xie contribute equally to this work.

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