Layal El-Hajjar1, Nour Jalaleddine1, Abdullah Shaito2, Kazem Zibara3, Jalal M Kazan4, Jamal El-Saghir5, Marwan El-Sabban6. 1. Department of Biological and Environmental Sciences, Faculty of Science, Beirut Arab University, Beirut, Lebanon. 2. Department of Biological and Chemical Sciences, Faculty of Arts and Sciences, Lebanese International University, Beirut, Lebanon. 3. ER045- Laboratory of Stem Cells, PRASE, Biology Department, Faculty of Sciences, Lebanese University, Beirut, Lebanon. Electronic address: kzibara@ul.edu.lb. 4. Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. Electronic address: jalal.kazan@mail.mcgill.ca. 5. Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. Electronic address: jae13@mail.aub.edu. 6. Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. Electronic address: me00@aub.edu.lb.
Abstract
BACKGROUND: Bevacizumab or Avastin® (Av) is an anti-vascular endothelial growth factor agent. It does not improve survival of breast cancer patients due to development of refractoriness. Av treatment was shown to increase inflammation in a diabetic mouse model, and also to induce epithelial-to-mesenchymal transition of non-transformed breast epithelia. This study aimed to understand if the Av-induced inflammatory microenvironment could be a mechanism of Av refractoriness. Expression profiles of inflammatory mediators, in vitro in MDA-MB-231 cells, in vivo in a mouse model xenografted with MDA-MB-231 cells and from archived cases of human breast carcinoma tissues were evaluated. Gap junctions are also crucial for angiogenesis and tumor cell extravasation. The effect of connexin 43 (Cx43) overexpression on the expression of inflammatory markers in MDA-MB-231 cells treated with Av was assessed. METHODS: MDA-MB-231 cells, control or overexpressing Cx43, were used in this study. Proliferation and invasion assays were performed. Quantitative PCR, ELISA and western blotting were performed to assess the regulation of inflammatory mediators and other factors upon Av treatment. Immunofluorescence was performed to document the translocation of Nuclear Factor-kappa B p65. RESULTS: Breast cancer tissues had elevated transcriptional levels of inflammatory mediators. Av treatment increased expression levels of inflammatory mediators and metastatic factors in vitro and in vivo. Interestingly, overexpressing Cx43 in MDA-MB-231 cells alleviated the inflammatory effects induced by Av treatment. CONCLUSION: This study attributes Av refractoriness to the Av therapy-induced inflammatory microenvironment.
BACKGROUND:Bevacizumab or Avastin® (Av) is an anti-vascular endothelial growth factor agent. It does not improve survival of breast cancerpatients due to development of refractoriness. Av treatment was shown to increase inflammation in a diabeticmouse model, and also to induce epithelial-to-mesenchymal transition of non-transformed breast epithelia. This study aimed to understand if the Av-induced inflammatory microenvironment could be a mechanism of Av refractoriness. Expression profiles of inflammatory mediators, in vitro in MDA-MB-231 cells, in vivo in a mouse model xenografted with MDA-MB-231 cells and from archived cases of humanbreast carcinoma tissues were evaluated. Gap junctions are also crucial for angiogenesis and tumor cell extravasation. The effect of connexin 43 (Cx43) overexpression on the expression of inflammatory markers in MDA-MB-231 cells treated with Av was assessed. METHODS: MDA-MB-231 cells, control or overexpressing Cx43, were used in this study. Proliferation and invasion assays were performed. Quantitative PCR, ELISA and western blotting were performed to assess the regulation of inflammatory mediators and other factors upon Av treatment. Immunofluorescence was performed to document the translocation of Nuclear Factor-kappa B p65. RESULTS:Breast cancer tissues had elevated transcriptional levels of inflammatory mediators. Av treatment increased expression levels of inflammatory mediators and metastatic factors in vitro and in vivo. Interestingly, overexpressing Cx43 in MDA-MB-231 cells alleviated the inflammatory effects induced by Av treatment. CONCLUSION: This study attributes Av refractoriness to the Av therapy-induced inflammatory microenvironment.
Authors: Samuel S Widodo; Ryan A Hutchinson; Yitong Fang; Stefano Mangiola; Paul J Neeson; Phillip K Darcy; Alexander D Barrow; Christopher M Hovens; Marija Dinevska; Stanley S Stylli; Theo Mantamadiotis Journal: Cancer Immunol Immunother Date: 2021-01-03 Impact factor: 6.968