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Updated: Jun 30, 2026

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins
Published on: September 28, 2012
hCCR4/cNOT6 targets DNA-damage response proteins
I Sanchez-Perez1, C Manguan-Garcia, M Menacho-Marquez
1Instituto de Investigaciones Biomédicas CSIC/UAM, Dpto. Modelos Experimentales de Enfermedades Humanas, Unidad de Oncologia Translacional. CIBER de Enfermadades Raras Valencia, Spain.
Abstract:
Radio and chemotherapy are the election options besides surgical resection, in cancer treatment. However, resistance to chemotherapy limits the effectiveness of therapy in the clinic. An improved knowledge of the mechanisms underlying the resistance to treatment would generate new therapeutic strategies. Genetic suppressor elements (GSEs) are short, biologically active, cDNA fragments that interfere with the function of their cognate gene. By selection of genetic suppressor elements (GSEs) conferring resistance to cisplatin, we identified the GSE11, that corresponds to the hCCR4/CNOT6 gene that mediates cellular sensitivity to the drug. Expression of GSE11-hCCR4 reduces hCCR4 protein levels in cells. Targeting hCCR4 with GSE11 or with siRNA, decreases sensitivity of mammalian cells to DNA-damaging agents. Overexpression of hCCR4 targets Chk2 following exposure to cisplatin, without interfering with the upstream ATM/ATR pathway, however histone gammaH2AX is strongly phosphorylated in these cells compared to control cells. Our results uncover a new function for a human protein involved in chemotherapy response. This finding introduces a new pharmacological target in the treatment of solid tumours.
Insights
Researchers identified a new target for cancer therapy by discovering how the hCCR4/CNOT6 gene influences chemotherapy resistance. Targeting this gene may improve treatments for solid tumors.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Genetics
Background:
- Chemotherapy is a primary cancer treatment, but drug resistance limits its effectiveness.
- Understanding resistance mechanisms is crucial for developing novel therapeutic strategies.
- Genetic suppressor elements (GSEs) offer a method to study gene function in cellular processes.
Purpose of the Study:
- To identify genes involved in cellular sensitivity or resistance to chemotherapy.
- To elucidate the role of the identified gene in response to DNA-damaging agents.
- To explore potential new therapeutic targets for solid tumors.
Main Methods:
- Selection of genetic suppressor elements (GSEs) conferring resistance to cisplatin.
- Identification of GSE11 corresponding to the hCCR4/CNOT6 gene.
- Assessment of hCCR4 protein levels and cellular sensitivity after targeting with GSE11 or siRNA.
- Analysis of downstream signaling pathways (Chk2, ATM/ATR, histone gammaH2AX phosphorylation) after cisplatin exposure.
Main Results:
- GSE11, corresponding to the hCCR4/CNOT6 gene, was identified as mediating cellular sensitivity to cisplatin.
- Reduced hCCR4 protein levels via GSE11 or siRNA decreased mammalian cell sensitivity to DNA-damaging agents.
- Overexpression of hCCR4 targeted Chk2 post-cisplatin exposure and increased histone gammaH2AX phosphorylation, independent of the ATM/ATR pathway.
Conclusions:
- The study uncovers a novel function for the human hCCR4 protein in chemotherapy response.
- Targeting hCCR4 presents a potential new pharmacological strategy for treating solid tumors.
- This research provides insights into mechanisms of chemotherapy resistance and potential therapeutic interventions.
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