HOXC10 Expression Supports the Development of Chemotherapy Resistance by Fine Tuning DNA Repair in Breast Cancer Cells
Abstract
Development of drug resistance is a major factor limiting the continued success of cancer chemotherapy. To overcome drug resistance, understanding the underlying mechanism(s) is essential. We found that HOXC10 is overexpressed in primary carcinomas of the breast, and even more significantly in distant metastasis arising after failed chemotherapy. High HOXC10 expression correlates with shorter recurrence-free and overall survival in patients with estrogen receptor–negative breast cancer undergoing chemotherapy. We found that HOXC10 promotes survival in cells treated with doxorubicin, paclitaxel, or carboplatin by suppressing apoptosis and upregulating NF-κB. Overexpressed HOXC10 increases S-phase–specific DNA damage repair by homologous recombination (HR) and checkpoint recovery in cells at three important phases. For double-strand break repair, HOXC10 recruits HR proteins at sites of DNA damage. It enhances resection and lastly, it resolves stalled replication forks, leading to initiation of DNA replication following DNA damage. We show that HOXC10 facilitates, but is not directly involved in DNA damage repair mediated by HR. HOXC10 achieves integration of these functions by binding to, and activating cyclin-dependent kinase, CDK7, which regulates transcription by phosphorylating the carboxy-terminal domain of RNA polymerase II. Consistent with these findings, inhibitors of CDK7 reverse HOXC10-mediated drug resistance in cultured cells. Blocking HOXC10 function, therefore, presents a promising new strategy to overcome chemotherapy resistance in breast cancer. Cancer Res; 76(15); 4443–56. ©2016 AACR.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 31, 2016
- Source ID
- 10.1158/0008-5472.can-16-0774
Entities
People
- Balazs Gyorffy
- Hardik Panday
- Helen Sadik
- Howard Y. Chang
- Jenny C. Chang
- Mohammad Hedayati
- Nguyen K. Nguyen
- Nilay Shah
- Otilia Menyhart
- Preethi Korangath
- Raj K. Pandita
- Rakesh Kumar
- Saraswati Sukumar
- Sunju Park
- Tej K. Pandita
- Teresa Gonzalez Munoz
- Theodore Deweese
- Wei Wen Teo
Organizations
- Houston Methodist Hospital
- Johns Hopkins University
- National Institutes of Health
- Semmelweis University
- Stanford University
- United States Department of Defense
- University of Texas at Austin