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Published on: May 20, 2015
Surface TRAIL decoy receptor-4 expression is correlated with TRAIL resistance in MCF7 breast cancer cells
Ahter D Sanlioglu1, Ercument Dirice, Cigdem Aydin
1The Human Gene Therapy Unit, Akdeniz University, Faculty of Medicine, Antalya, Turkey. ahter@akdeniz.edu.tr
Background:
Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) selectively induces apoptosis in cancer cells but not in normal cells. Despite this promising feature, TRAIL resistance observed in cancer cells seriously challenged the use of TRAIL as a death ligand in gene therapy. The current dispute concerns whether or not TRAIL receptor expression pattern is the primary determinant of TRAIL sensitivity in cancer cells. This study investigates TRAIL receptor expression pattern and its connection to TRAIL resistance in breast cancer cells. In addition, a DcR2 siRNA approach and a complementary gene therapy modality involving IKK inhibition (AdIKKbetaKA) were also tested to verify if these approaches could sensitize MCF7 breast cancer cells to adenovirus delivery of TRAIL (Ad5hTRAIL).
Methods:
TRAIL sensitivity assays were conducted using Molecular Probe's Live/Dead Cellular Viability/Cytotoxicity Kit following the infection of breast cancer cells with Ad5hTRAIL. The molecular mechanism of TRAIL induced cell death under the setting of IKK inhibition was revealed by Annexin V binding. Novel quantitative Real Time RT-PCR and flow cytometry analysis were performed to disclose TRAIL receptor composition in breast cancer cells.
Results:
MCF7 but not MDA-MB-231 breast cancer cells displayed strong resistance to adenovirus delivery of TRAIL. Only the combinatorial use of Ad5hTRAIL and AdIKKbetaKA infection sensitized MCF7 breast cancer cells to TRAIL induced cell death. Moreover, novel quantitative Real Time RT-PCR assays suggested that while the level of TRAIL Decoy Receptor-4 (TRAIL-R4) expression was the highest in MCF7 cells, it was the lowest TRAIL receptor expressed in MDA-MB-231 cells. In addition, conventional flow cytometry analysis demonstrated that TRAIL resistant MCF7 cells exhibited substantial levels of TRAIL-R4 expression but not TRAIL decoy receptor-3 (TRAIL-R3) on surface. On the contrary, TRAIL sensitive MDA-MB-231 cells displayed very low levels of surface TRAIL-R4 expression. Furthermore, a DcR2 siRNA approach lowered TRAIL-R4 expression on surface and this sensitized MCF7 cells to TRAIL.
Conclusion:
The expression of TRAIL-R4 decoy receptor appeared to be well correlated with TRAIL resistance encountered in breast cancer cells. Both adenovirus mediated IKKbetaKA expression and a DcR2 siRNA approach sensitized MCF7 breast cancer cells to TRAIL.
Insights
Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) resistance in breast cancer cells is linked to high TRAIL-R4 decoy receptor expression. Inhibiting IKK or using DcR2 siRNA can sensitize resistant cells to TRAIL-based gene therapy.
Area of Science:
- Oncology
- Molecular Biology
- Gene Therapy
Background:
- Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) selectively induces apoptosis in cancer cells, but resistance limits its therapeutic use.
- Understanding TRAIL resistance mechanisms is crucial for developing effective cancer gene therapies.
Purpose of the Study:
- Investigate the role of TRAIL receptor expression in breast cancer cell sensitivity to TRAIL.
- Evaluate strategies to overcome TRAIL resistance, including IKK inhibition and DcR2 siRNA, in combination with adenovirus-mediated TRAIL delivery.
Main Methods:
- TRAIL sensitivity assays using Live/Dead Cellular Viability/Cytotoxicity Kit.
- Quantitative Real Time RT-PCR and flow cytometry to analyze TRAIL receptor expression.
- Annexin V binding to assess TRAIL-induced cell death mechanisms under IKK inhibition.
Main Results:
- MCF7 cells showed resistance to Ad5hTRAIL, unlike MDA-MB-231 cells.
- High expression of TRAIL Decoy Receptor-4 (TRAIL-R4) correlated with TRAIL resistance in MCF7 cells.
- DcR2 siRNA and AdIKKbetaKA infection sensitized MCF7 cells to Ad5hTRAIL by reducing TRAIL-R4 levels.
Conclusions:
- TRAIL-R4 decoy receptor expression is a key determinant of TRAIL resistance in breast cancer.
- Targeting TRAIL-R4 or inhibiting IKK can enhance TRAIL-induced apoptosis in resistant breast cancer cells, offering potential therapeutic strategies.
