Proteomics of the Radioresistant Phenotype in Head-and-Neck Cancer: Gp96 as a Novel Prediction Marker and Sensitizing Target for Radiotherapy

Journal Article · Wed Sep 01 00:00:00 EDT 2010 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.03.002· OSTI ID:21436162

Lin, Ting-Yang ^[1]; Chang, Joseph Tung-Chieh ^[2]; Wang, Hung-Ming ^[2]

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1. Department of Medical Biotechnology, Chang Gung University, Taoyuan, Taiwan (China)
2. Department of Medicine, Chang Gung University, Taoyuan, Taiwan (China)

Purpose: Radiotherapy is an integral part of the treatment modality for head-neck cancer (HNC), but in some cases the disease is radioresistant. We designed this study to identify molecules that may be involved in this resistance. Methods and Materials: Two radioresistant sublines were established by fractionated irradiation of the HNC cell lines, to determine differentially proteins between parental and radioresistant cells. Proteomic analysis and reverse-transcription polymerase chain reaction were used to identify and confirm the differential proteins. The siRNA knockdown experiments were applied to examine cellular functions of a radioresistant gene, with investigation of the alterations in colonogenic survival, cell cycle status, and reactive oxygen species levels. Xenografted mouse tumors were studied to validate the results. Results: IN all, 64 proteins were identified as being potentially associated with radioresistance, which are involved in several cellular pathways, including regulation of stimulus response, cell apoptosis, and glycolysis. Six genes were confirmed to be differentially expressed in both radioresistant sublines, with Gp96, Grp78, HSP60, Rab40B, and GDF-15 upregulated, and annexin V downregulated. Gp96 was further investigated for its functions in response to radiation. Gp96-siRNA transfectants displayed a radiation-induced growth delay, reduction in colonogenic survival, increased cellular reactive oxygen species levels, and increased proportion of the cells in the G2/M phase. Xenograft mice administered Gp96-siRNA showed significantly enhanced growth suppression in comparison with radiation treatment alone (p = 0.009). Conclusions: We identified 64 proteins and verified 6 genes that are potentially involved in the radioresistant phenotype. We further demonstrated that Gp96 knockdown enhances radiosensitivity both in cells and in vivo, which may lead to a better prognosis of HNC treatment.

• OSTI ID: 21436162
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 78, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2010.03.002; PII: S0360-3016(10)00395-0; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BIOLOGICAL MARKERS
FORECASTING
FRACTIONATED IRRADIATION
HEAD
MICE
NECK
NEOPLASMS
PHENOTYPE
POLYMERASE CHAIN REACTION
PROTEINS
RADIOSENSITIVITY
RADIOTHERAPY
ANIMALS
BODY
DISEASES
GENE AMPLIFICATION
IRRADIATION
MAMMALS
MEDICINE
NUCLEAR MEDICINE
ORGANIC COMPOUNDS
RADIOLOGY
RODENTS
SENSITIVITY
THERAPY
VERTEBRATES