Meloxicam combined with temozolomide synergistically inhibits cell migration and induces apoptosis via the inhibition of AKT pathway in glioblastoma cell line LN18

Abstract

Temozolomide (TMZ) is a widely known and promising therapeutic option for advanced glioblastoma multiforme (GBM). However, the recurrence of GBM due to intrinsic factors or acquired therapeutic resistance necessitates the development of novel treatments. Meloxicam (MEL), a potent selective cyclooxygenase (COX-2) inhibitor, has been widely reported as an inhibitor of proliferation and invasion/migration in various tumors. In this study, we investigated the interaction of TMZ and MEL in GBM cell line LN18, and their potential combinatorial impact on cell biological activity and related downstream signaling pathways. MTT method was used to detect cell growth inhibition rate and scratch assay was applied to analyze the inhibitory effect on tumor cell migration. Fluorescence-activated cell sorting (FACS) was performed to assess the rate of apoptosis. Tumor cells (LN18) were incubated with the concerned drugs and high-quality protein lysate was prepared using magnetic beads method, which effectively absorbs target proteins. Western blotting was employed to detect PI3K/AKT signaling pathway and apoptosis-related protein caspase-3. We found that lower dose of TMZ or MEL alone minimally induced apoptosis and only modestly compromised the migration of LN18 cells in vitro through the inhibition of AKT. Interestingly, the combinatorial treatment with TMZ and MEL was found to present a synergistic antitumor efficacy. MEL combined with TMZ down-regulated AKT activation, indicating that such a treatment could effectively impair PI3K/AKT signaling pathway to induce tumor cell apoptosis and better inhibit tumor cell migration. These findings provide insights into the significance of combinatorial treatment for GBM.