title: Temozolomide-modulated glioma proteome: role of interleukin-1 receptor-associated kinase-4 (IRAK4) in chemosensitivity.
abstract: The current treatment for glioblastoma includes temozolomide (TMZ) chemotherapy, yet the mechanism of action of TMZ is not thoroughly understood. Here, we investigated the TMZ-induced changes in the proteome of the glioma-derived cell line (U251) by 2D DIGE. We found 95 protein spots to be significantly altered in their expression after TMZ treatment. MS identified four upregulated spots: aspartyl tRNA synthetase glutathione synthetase, interleukin-1 receptor-associated kinase-4 (IRAK4), and breast carcinoma amplified sequence-1 and one downregulated spot: optineurin. TMZ-induced regulation of these five genes was validated by RT-qPCR and Western blot analysis. RNAi-mediated knockdown of IRAK4, an important mediator of Toll-like receptors signaling and chemoresistance, rendered the glioma cells resistant to TMZ. High levels of IRAK4 induced upon TMZ treatment resulted in IRAK1 downregulation and inhibition of NFkB pathway. Endogenous IRAK4 protein, but not transcript levels in glioma cell lines, correlated with TMZ sensitivity. Thus, we have identified several TMZ-modulated proteins and discovered an important novel role for IRAK4 in determining TMZ sensitivity of glioma cells through its ability to inhibit Toll-like receptor signaling and NFkB pathway.
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
authors.forename: Durairaj M
authors.initials: DM
authors.lastname: Kumar
authors.forename: Vikas
authors.initials: V
authors.lastname: Patil
authors.forename: Bini
authors.initials: B
authors.lastname: Ramachandran
authors.forename: Murugesan V
authors.initials: MV
authors.lastname: Nila
authors.forename: Kuppamuthu
authors.initials: K
authors.lastname: Dharmalingam
authors.forename: Kumaravel
authors.initials: K
authors.lastname: Somasundaram
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D016000:Cluster Analysis; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004121:Dimethyl Sulfoxide; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D015180:Electrophoresis, Gel, Two-Dimensional; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism*; D006801:Humans; D053592:Interleukin-1 Receptor-Associated Kinases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D020543:Proteome / Q000032:analysis / Q000187:drug effects*; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D015398:Signal Transduction / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000077204:Temozolomide; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D018906:Antineoplastic Agents, Alkylating; D016328:NF-kappa B; D020543:Proteome; D034741:RNA, Small Interfering; D051193:Toll-Like Receptors; D003606:Dacarbazine; D053592:Interleukin-1 Receptor-Associated Kinases; D000077204:Temozolomide; D004121:Dimethyl Sulfoxide
keywords: 2D DIGE; BCAS1; Cell biology; GBM; GSS; IRAK4; TMZ