Abstract | PURPOSE: Neoadjuvant concurrent chemoradiotherapy (CCRT) is a gold standard treatment for patients with stage II/III rectal cancer. B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) is a member of the polycomb group of proteins that are involved in regulating gene expression. High levels of BMI1 have been demonstrated to contribute to the malignant phenotypes of several cancers; however, its relevance in rectal cancer treated with CCRT is largely unknown. METHODS AND MATERIALS: We used two patient cohorts to address the clinical relevance of BMI1 in human cancers. In addition, HT-29 and HCT-116 cells were chosen as our in vitro models to verify the role of BMI1 in cell response to ionizing radiation. Stemness-related proteins were analyzed by western blotting and cell survival was determined using clonogenic assays. RESULTS: BMI1 overexpression was found to significantly correlate with advanced pre-treatment nodal status (N1-N2; p < 0.001), post-treatment tumor stage (T1-T2; p = 0.015), inferior tumor regression grade (p = 0.001), and also an independent prognosis factor in 172 rectal cancer patients receiving CCRT. Serial cell-based functional examination indicated that BMI1 deficiency sensitized cells to radiation treatment by modulating the gene expression of Kruppel-like factor 4 (KLF4) and enhanced radiosensitivity in microsatellite stable (MSS) colorectal cancers. Overexpression of KLF4 partially overcame BMI1-deficiency-mediated γ-H2AX expression after ionizing radiation exposure. Consistent with in vitro data, an analysis of an additional 30 rectal cancer tissue specimens revealed a positive correlation between BMI1 and KLF4 (p = 0.02). CONCLUSION: Higher levels of BMI1 are associated with poor therapeutic response and adverse outcomes in rectal cancer patients receiving CCRT.
|
Authors | Yin-Chou Hsu, Chi-Wen Luo, Wei-Lun Huang, Chun-Chieh Wu, Chia-Lin Chou, Chih-I Chen, Shu-Jyuan Chang, Chee-Yin Chai, Hui-Ching Wang, Tzu-Yi Chen, Chien-Feng Li, Mei-Ren Pan |
Journal | Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
(Radiother Oncol)
Vol. 149
Pg. 249-258
(08 2020)
ISSN: 1879-0887 [Electronic] Ireland |
PMID | 32592893
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
Copyright | Copyright © 2020 Elsevier B.V. All rights reserved. |
Chemical References |
- BMI1 protein, human
- Biomarkers, Tumor
- Bmi1 protein, mouse
- KLF4 protein, human
- Klf4 protein, mouse
- Kruppel-Like Factor 4
- Kruppel-Like Transcription Factors
- Proto-Oncogene Proteins
- Polycomb Repressive Complex 1
|
Topics |
- Animals
- Biomarkers, Tumor
- Chemoradiotherapy
(adverse effects)
- Humans
- Kruppel-Like Factor 4
- Kruppel-Like Transcription Factors
- Mice
- Neoadjuvant Therapy
- Polycomb Repressive Complex 1
(genetics)
- Prognosis
- Proto-Oncogene Proteins
(genetics)
- Rectal Neoplasms
(drug therapy, therapy)
|