title: Microglia Activate Migration of Glioma Cells through a Pyk2 Intracellular Pathway.
abstract: Glioblastoma is one of the most aggressive and fatal brain cancers due to the highly invasive nature of glioma cells. Microglia infiltrate most glioma tumors and, therefore, make up an important component of the glioma microenvironment. In the tumor environment, microglia release factors that lead to the degradation of the extracellular matrix and stimulate signaling pathways to promote glioma cell invasion. In the present study, we demonstrated that microglia can promote glioma migration through a mechanism independent of extracellular matrix degradation. Using western blot analysis, we found upregulation of proline rich tyrosine kinase 2 (Pyk2) protein phosphorylated at Tyr579/580 in glioma cells treated with microglia conditioned medium. This upregulation occurred in rodent C6 and GL261 as well as in human glioma cell lines with varying levels of invasiveness (U-87MG, A172, and HS683). siRNA knock-down of Pyk2 protein and pharmacological blockade by the Pyk2/focal-adhesion kinase (FAK) inhibitor PF-562,271 reversed the stimulatory effect of microglia on glioma migration in all cell lines. A lower concentration of PF-562,271 that selectively inhibits FAK, but not Pyk2, did not have any effect on glioma cell migration. Moreover, with the use of the CD11b-HSVTK microglia ablation mouse model we demonstrated that elimination of microglia in the implanted tumors (GL261 glioma cells were used for brain implantation) by the local in-tumor administration of Ganciclovir, significantly reduced the phosphorylation of Pyk2 at Tyr579/580 in implanted tumor cells. Taken together, these data indicate that microglial cells activate glioma cell migration/dispersal through the pro-migratory Pyk2 signaling pathway in glioma cells.
authors.affiliation: Department of Biochemistry, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Kimberleve
authors.initials: K
authors.lastname: Rolón-Reyes
authors.affiliation: Department of Biochemistry, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Yuriy V
authors.initials: YV
authors.lastname: Kucheryavykh
authors.affiliation: Department of Anatomy and Cell Biology, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Cubano
authors.affiliation: Department of Physiology, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Inyushin
authors.affiliation: Department of Biochemistry, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America; Department of Physiology, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Serguei N
authors.initials: SN
authors.lastname: Skatchkov
authors.affiliation: Department of Biochemistry, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Misty J
authors.initials: MJ
authors.lastname: Eaton
authors.affiliation: Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, Florida.
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Harrison
authors.affiliation: Department of Biochemistry, Universidad Central del Caribe, School of Medicine, Bayamón, Puerto Rico, United States of America.
authors.forename: Lilia Y
authors.initials: LY
authors.lastname: Kucheryavykh
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000473:pathology / Q000503:physiopathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D051418:Focal Adhesion Kinase 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D055785:Gene Knockdown Techniques; D005910:Glioma / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017628:Microglia / Q000473:pathology / Q000502:physiology*; D009361:Neoplasm Invasiveness / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D015398:Signal Transduction / Q000502:physiology; D059016:Tumor Microenvironment / Q000502:physiology; D015854:Up-Regulation
chemical_list: D051418:Focal Adhesion Kinase 2