Abstract 1896: Blockade of laminin-411-notch crosstalk as an effective therapy for glioblastoma treatment

Abstract

Abstract Purpose: The extracellular matrix (ECM) in tumor microenvironment including laminins is important for tumor development, and we aimed to develop an effective glioblastoma therapy via blocking the communication between tumor and their microenvironment mediated by laminin-411-Notch axis. Methods: The glioma vascular protein, laminin-411(α4β1γ1) expression was examined in >200 glioma patient specimens by immunohistochemistry. In glioblastoma bearing mice, laminin-411 expression in tumor cells was disrupted by CRISPR/Ca9 system, and its impact on two glioblastoma cell lines was studied in intracranial xenografts. Laminin-411-Notch crosstalk was further dissected in vitro using cell cultures. Finally, a nanobioconjugate was developed to block laminin-411 expression in vivo. The effects of blocking laminin-411-Notch axis via systemic administration of this nanodrug were investigated in vivo using MRI, immunohistochemistry, western blot and survival analysis. Results: Laminin-411 (α4β1γ1) expression in a panel of 226 patient brain glioma samples was correlated with higher tumor grade, and expression of cancer stem cell (CSC) markers including Notch pathway, CD133, Nestin, and c-Myc. Laminin-411 overexpression was also correlated with higher recurrence rate and shorter survival of glioma patients. Depletion of laminin-411 α4 and β1 chains with CRISPR/Cas9 in human glioblastoma cells led to slower growth of resultant intracranial tumors compared to wild type tumors as revealed by MRI. Concomitantly, survival of host animals carrying the laminin-411 knockout tumors was significantly increased. Mechanistic studies in vitro and in vivo showed that laminin-411 inhibition suppressed Notch pathway in both normal and malignant human brain cell types. A nanobioconjugate potentially suitable for clinical use and capable of crossing blood-brain barrier was designed to block laminin-411 expression. Nanobioconjugate treatment of mice carrying intracranial glioblastoma significantly increased animal survival and inhibited multiple CSC markers including Notch axis. Conclusion: The depletion of “malignant” laminin-411 α4 and β1 chains with CRISPR/Cas9 led to slower growth of resultant intracranial tumors compared to wild type tumors, and a systemic nanodrug treatment to inhibit laminin-411-Notch crosstalk provides a new strategy for glioblastoma treatment. This study demonstrates a new strategy of glioblastoma treatment through targeting a critical component of tumor microenvironment, largely independent of heterogeneous genetic mutations in the tumor. Citation Format: Dmytro Klymyshyn, Anna Galstyan, Rameshwar Patil, Hui Ding, Ekaterina Shatalova, Shawn Wagner, Keith Black, Alexander Ljubimov, Eggehard Holler, Julia Ljubimova, Tao Sun. Blockade of laminin-411-notch crosstalk as an effective therapy for glioblastoma treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1896.