Extracellular Matrix Proteins Confer Cell Adhesion-Mediated Drug Resistance Through Integrin αv in Glioblastoma Cells

Abstract

Chemotherapy resistance to glioblastoma (GBM) remains an obstacle that is difficult to overcome, leading to poor prognosis of GBM patients. Many previous studies have focused on resistance mechanisms intrinsic to cancer cells; the microenvironment surrounding tumor cells has been found more recently to have significant impacts on the response to chemotherapeutic agents. Extracellular matrix (ECM) proteins may confer cell adhesion-mediated drug resistance (CAMDR). Here, expression of the ECM proteins laminin, vitronectin, and fibronectin was assessed in clinical GBM tumors using immunohistochemistry. Then, patient-derived GBM cells grown in monolayers on precoated laminin, vitronectin, or fibronectin substrates were treated with cilengitide, an integrin inhibitor, and/or carmustine, an alkylating chemotherapy. Cell adhesion and viability were quantified. Transcription factor (TF) activities were assessed over time using a bioluminescent assay in which GBM cells were transduced with lentiviruses containing consensus binding sites for specific TFs linked to expression a firefly luciferase reporter. Apoptosis, mediated by p53, was analyzed by Western blotting and immunocytofluorescence. Integrin αv activation of the FAK/paxillin/AKT signaling pathway and effects on expression of the proliferative marker Ki67 were investigated. To assess effects of integrin αv activation of AKT and ERK pathways, which are typically deregulated in GBM, and expression of epidermal growth factor receptor (EGFR), which is amplified and/or mutated in many GBM tumors, shRNA knockdown was used. Laminin, vitronectin, and fibronectin were abundant in clinical GBM tumors and promoted CAMDR in GBM cells cultured on precoated substrates. Cilengitide treatment induced cell detachment, which was most pronounced for cells cultured on vitronectin. Cilengitide treatment increased cytotoxicity of carmustine, reversing CAMDR. ECM adhesion increased activity of NFκB and decreased that of p53, leading to suppression of p53-mediated apoptosis and upregulation of multidrug resistance gene 1 (MDR1; also known as ABCB1 or P-glycoprotein). Expression of Ki67 was correlative with activation of the integrin αv-mediated FAK/paxillin/AKT signaling pathway. EGFR expression increased with integrin αv knockdown GBM cells and may represent a compensatory survival mechanism. These results indicate that ECM proteins confer CAMDR through integrin αv in GBM cells.

Tuning Hydrogel Adhesivity and Degradability to Model the Influence of Premetastatic Niche Matrix Properties on Breast Cancer Dormancy and Reactivation

“…[9,14,16,[45][46][47][48] Hydrogels have been widely implemented to develop tissue engineered constructs that mimic various aspects of the tumor microenvironment. [5,[19][20][21][22][23][24][25][26][27][28][29] For instance, natural hydrogels have been implemented to model the tumor microenvironment using proteins such as collagen, gelatin, and fibrin and polysaccharides such as hyaluronic acid and alginate have been incorporated to produce semi-synthetic hydrogels. [49][50][51] While these hydrogels provide relevant biochemical properties, batch to batch variability, viscosity, and limitations concerning independent control of mechanical and biochemical properties are often challenging obstacles to overcome with when using these materials.…”

“…It is well established that cell-ECM interactions play a key role in governing cancer cell fate. [5,[19][20][21][22][23][24][25][26][27][28][29] In this context, we previously developed sixteen unique hydrogel formulations composed of three components: (1) proteolytically degradable PEG (PEG-PQ), (2) integrin ligating PEG-RGDS, and (3) a nondegradable crosslinker NVP. By systematically tuning the concentration of PEG-RGDS and NVP, hydrogel adhesivity and degradability were varied, inducing different phenotypes in the parental triple negative breast cancer line (MDA-MB-231) and three of its organotropic sublines (BRM2a-831s, LM2-4175s, BoM-1833s).…”

TGFβ1 Improves the Proliferation of Decellularized and Aligned Skeletal Muscle in Extracellular Matrix Hydrogels by m6A Modification-Mediated Integrin Through Inducing ERK Phosphorylation

“…Integrin activates FAK/paxillin/AKT signaling pathway and affects the expression of the proliferative marker Ki67 in tumors [44]. Recent studies have shown that transmembrane integrin α2β1 directly interacts with lumican, and activates ERK and ALP activities in osteoblasts [45].…”

Integrin-αvβ3 as a Therapeutic Target in Glioblastoma: Back to the Future?

“…In addition to the intrinsic resistance of cancer cells, their high heterogeneity, and the poor drug penetration through the blood-brain barrier, the tumor microenvironment was recently found to significantly impact the response to standard therapies. High levels of vitronectin and fibronectin were detected in clinical GBM tumors and found to confer cell-adhesion-mediated drug resistance [ 65 ]. In this setting, fibronectin suppressed p53-mediated apoptosis and upregulated P-glycoprotein expression, also known as multidrug resistance protein 1 (MDR1), making glioma cells chemoresistant.…”