UCP2 silencing in glioblastoma reduces cell proliferation and invasiveness by inhibiting p38 MAPK pathway

Uncoupling protein-2 (UCP2) is a mitochondrial inner membrane anion carrier and is emerging as a negative regulator of ROS production. Overexpression of UCP2 has been detected in various tumors, but its role in glioblastoma remains unclear. Using tissue microarrays and interrogations of public databases, we explored that the expression of UCP2 is upregulated in glioma, especially in GBM, and overexpression of UCP2 correlates with poor prognosis in glioma patients. To further reveal the role of UCP2 in glioma, UCP2-slienced cell lines (U251, U87MG and A172) by lentivirus were constructed to study how silenced UCP2 expression affects cellular functions in vitro, and tumorigenicity in vivo. RNA-Seq based genome and pathway analysis were performed to elucidate the underlying mechanisms of action of UCP2. Our results revealed that UCP2 silenced glioma cells show inhibited migration, invasiveness, clonogenicity, proliferation, promoted cell apoptosis in vitro, and weaker tumorigenicity in nude mice. Transcriptome analysis suggested a UCP2-dependent regulation of p38 MAPK (Mitogen-activated protein kinase) signaling networks, which was further validated by qRT-PCR and Western blot. Our research provides a new insight into the biological significance of UCP2 in glioma and its potential application in treatment and diagnosis.