TRIM24 promotes glioma progression and enhances chemoresistance through activation of the PI3K/Akt signaling pathway.
The tripartite motif protein TRIM24 (tripartite motif-containing 24) has been found to play distinct roles in tumor development and progression, according to different tumor contexts. However, it remains elusive whether TRIM24 plays a role in malignant gliomas that are the most common and deadly primary brain tumors in adults. We report here that TRIM24 expression is positively correlated with glioma malignancy and is negatively associated with prognosis of patients with newly diagnosed glioblastoma, which is the most malignant form of gliomas but displays highly heterogeneous clinical outcome. The multivariate Cox regression analysis demonstrates the independent predictive value of TRIM24 expression level for overall and progression-free survival. Knockdown of TRIM24 suppresses cell proliferation, cell cycle progression, clone formation and in vivo tumor development, whereas overexpression of TRIM24 promotes cell growth. Chromatin immunoprecipitation, real-time reverse transcription-PCR and mutation analyses demonstrate that TRIM24 binds to the PIK3CA promoter via its PHD-Bromo domain to activate the transcription of PIK3CA gene, thus enhancing phosphatidylinositide 3-kinase (PI3K)/Akt signaling. The pan-PI3K inhibitor LY294002 and small interfering RNA targeting PIK3CA both abrogate the growth-promoting effect of TRIM24. Moreover, TRIM24 regulates the expression of DNA repair enzyme O(6)-methylguanine-DNA methyltransferase (MGMT) through PI3K/Akt/nuclear factor-κB signaling transduction and enhances resistance to temozolomide, the standard chemotherapeutic agent for glioblastoma. Finally, glioblastoma patients with low TRIM24 expression benefit from chemotherapy, whereas those with high TRIM24 expression do not have such benefit. Our results suggest that TRIM24 might serve as a potential prognostic marker and therapeutic target for the management of malignant gliomas.
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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LH
Zhang
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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AA
Yin
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
J-X
JX
Cheng
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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HY
Huang
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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XM
Li
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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YQ
Zhang
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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N
Han
Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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X
Zhang
D000328:Adult; D000368:Aged; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D058534:Class I Phosphatidylinositol 3-Kinases; D015254:DNA Modification Methylases / Q000378:metabolism; D045643:DNA Repair Enzymes / Q000378:metabolism; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D009367:Neoplasm Staging; D051058:Oncogene Protein v-akt / Q000235:genetics*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000187:drug effects; D025521:Tumor Suppressor Proteins / Q000378:metabolism
D002352:Carrier Proteins; C555317:TRIM24 protein, human; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human; D051058:Oncogene Protein v-akt; D045643:DNA Repair Enzymes