ERp57 modulates STAT3 activity in radioresistant laryngeal cancer cells and serves as a prognostic marker for laryngeal cancer.

Abstract

Although targeting radioresistant tumor cells is essential for enhancing the efficacy of radiotherapy, the signals activated in resistant tumors are still unclear. This study shows that ERp57 contributes to radioresistance of laryngeal cancer by activating STAT3. Increased ERp57 was associated with the radioresistant phenotype of laryngeal cancer cells. Interestingly, increased interaction between ERp57 and STAT3 was observed in radioresistant cells, compared to the control cells. This physical complex is required for the activation of STAT3 in the radioresistant cells. Among STAT3-regulatory genes, Mcl-1 was predominantly regulated by ERp57. Inhibition of STAT3 activity with a chemical inhibitor or siRNA-mediated depletion of Mcl-1 sensitized radioresistant cells to irradiation, suggesting that the ERp57-STAT3-Mcl-1 axis regulates radioresistance of laryngeal cancer cells. Furthermore, we observed a positive correlation between ERp57 and phosphorylated STAT3 or Mcl-1 and in vivo interactions between ERp57 and STAT3 in human laryngeal cancer. Importantly, we also found that increased ERp57-STAT3 complex was associated with poor prognosis in human laryngeal cancer, indicating the prognostic role of ERp57-STAT3 regulation. Overall, our data suggest that ERp57-STAT3 regulation functions in radioresistance of laryngeal cancer, and targeting the ERp57-STAT3 pathway might be important for enhancing the efficacy of radiotherapy in human laryngeal cancer.

• Authors: Min Ho Choe, Joong Won Min, Hong Bae Jeon, Dong-Hyung Cho, Jeong Su Oh, Hyun Gyu Lee, Sang-Gu Hwang, Sungkwan An, Young-Hoon Han, Jae-Sung Kim
• Journal: Oncotarget (Oncotarget) Vol. 6 Issue 5 Pg. 2654-66 (Feb 20 2015) ISSN: 1949-2553 [Electronic] United States
• PMID: 25605256 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• MCL1 protein, human
• Myeloid Cell Leukemia Sequence 1 Protein
• STAT3 Transcription Factor
• STAT3 protein, human
• Protein Disulfide-Isomerases
• PDIA3 protein, human

Topics

• Biomarkers, Tumor (genetics, metabolism)
• Carcinoma, Squamous Cell (enzymology, genetics, pathology, radiotherapy)
• Cell Line, Tumor
• Gene Expression Regulation, Enzymologic
• Gene Expression Regulation, Neoplastic
• Head and Neck Neoplasms (enzymology, genetics, pathology, radiotherapy)
• Humans
• Laryngeal Neoplasms (enzymology, genetics, pathology, radiotherapy)
• Myeloid Cell Leukemia Sequence 1 Protein (genetics, metabolism)
• Phenotype
• Phosphorylation
• Prognosis
• Protein Binding
• Protein Disulfide-Isomerases (genetics, metabolism)
• RNA Interference
• Radiation Tolerance
• STAT3 Transcription Factor (genetics, metabolism)
• Signal Transduction (radiation effects)
• Squamous Cell Carcinoma of Head and Neck
• Time Factors
• Transfection