Faculty Collaboration Database

Irradiation-induced angiogenesis is associated with an MMP-9-miR-494-syndecan-1 regulatory loop in medulloblastoma cells. Oncogene 2014 Apr 10;33(15):1922-33

Date

06/04/2013

Pubmed ID

23728345

DOI

10.1038/onc.2013.151

Scopus ID

2-s2.0-84899448152 (requires institutional sign-in at Scopus site)   60 Citations

Abstract

Matrix metalloproteinase-9 (MMP-9) represents one of the most prominent proteins associated with tumorigenesis and is a modulator of the tumor microenvironment during angiogenesis. Recently, syndecan-1 (SDC1), a transmembrane heparan sulfate-bearing proteoglycan, was also speculated to have a critical role in contributing to angiogenesis when associated with MMP-9. However, the mechanism behind their synergistic regulation is not fully understood. In the current study, we report for the first time that ionizing radiation (IR)-induced MMP-9 enhances SDC1 shedding, corroborating to tube-inducing ability of medulloblastoma (MB) cells. Furthermore, we observed that the tumor angiogenesis is associated with higher MMP-9-SDC1 interactions on both the cell surface and extracellular medium. Our results also revealed the existence of a novel regulatory mechanism where MMP-9 drives the suppression of miR-494, resulting in enhanced SDC1 shedding and angiogenesis. From the in situ hybridization analysis, we found that MMP-9-specific shRNA (shMMP-9) treatment of mouse intracranial tumors resulted in elevated expression of miR-494. This negative correlation between MMP-9 and miR-494 levels was observed to be dependent on the methylation status of a miR-494 promoter-associated CpG island region (-186 to -20), which was confirmed by bisulfite-sequencing and methylation-specific PCR (MSP) analysis. Further, validation of MMP-9 and SDC1 3'-untranslated region (3'-UTR) targets with luciferase reporter assay provided a more favorable result for miR-494-mediated regulation of SDC1 but not of MMP-9, suggesting that the 3'-UTR of SDC1 mRNA is a direct target of miR-494. Overall, our results indicate that angiogenesis induced by radiotherapy is associated with an MMP-9-miR-494-SDC1 regulatory loop and that MMP-9-SDC1 activity creates a negative feedback loop by regulating the expression of miR-494.

Author List

Asuthkar S, Velpula KK, Nalla AK, Gogineni VR, Gondi CS, Rao JS

MESH terms used to index this publication - Major topics in bold

Adolescent
Animals
Cell Line, Tumor
Cerebellar Neoplasms
Child
Child, Preschool
Feedback, Physiological
Gene Expression Regulation, Neoplastic
Heterografts
Humans
Immunoblotting
Immunohistochemistry
In Situ Hybridization
Matrix Metalloproteinase 9
Medulloblastoma
Mice
Mice, Nude
MicroRNAs
Neovascularization, Pathologic
RNA, Small Interfering
Radiation, Ionizing
Real-Time Polymerase Chain Reaction
Reverse Transcriptase Polymerase Chain Reaction
Syndecan-1