OncoTargets and Therapy (Sep 2016)
Differential proteomics analysis of low- and high-grade of astrocytoma using iTRAQ quantification
Abstract
Tong Ren,1,* Shide Lin,2,* Zhongfeng Wang,3 Aijia Shang4 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 2Department of Spinal Cord Injury, Institute of Orthopedics and Traumatology of Chinese PLA, General Hospital of Jinan Military Area Command, Jinan, 3State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai, 4Department of Neurosurgery, General Hospital of Chinese People’s Liberation Army of China, Beijing, People’s Republic of China *These authors contributed equally to this work Abstract: Astrocytoma is one of the most common types of brain tumor, which is histologically and clinically classified into four grades (I–IV): I (pilocytic astrocytoma), II (diffuse astrocytoma), III (anaplastic astrocytoma), and IV (glioblastoma multiforme). A higher grade astrocytoma represents a worse prognosis and is more aggressive. In this study, we compared the differential proteome profile of astrocytoma from grades I to IV. The protein samples from clinical specimens of grades I, II, III, and IV astrocytoma were analyzed by two-dimensional liquid chromatography–tandem mass spectrometry and isobaric tags for relative and absolute quantitation and quantification. A total of 2,190 proteins were identified. Compared to grade I astrocytoma, 173 (12.4%), 304 (14%), and 462 (21.2%) proteins were aberrantly expressed in grades II, III, and IV, respectively. By bioinformatics analysis, the cell proliferation, invasion, and angiogenesis-related pathways increase from low- to high-grade of astrocytoma. Five differentially expressed proteins were validated by Western blot. Within them, matrix metalloproteinase-9 and metalloproteinase inhibitor 1 were upregulated in glioblastoma multiforme group; whereas fibulin-2 and -5 were downregulated in grade II/III/IV astrocytoma, and the negative expression was significantly associated with advanced clinical stage. Functional analysis showed that both fibulin-2 and -5 may exert an antitumor effect by inhibiting cell proliferation, in vitro migration/invasion in glioma cells. New molecular biomarkers are likely to be used for accurate classification of astrocytoma and likely to be the target for drug development. Keywords: brain tumor, glioma, astrocytoma, clinical grades, bio-markers, Fibulin-2, Fibulin-5
