Microarray determination of Bcl-2 family protein inhibition sensitivity in breast cancer cells
Sandra G Hudson1, Devin R Halleran, Barbara Nevaldine
1Department of Radiation Oncology, The State University of New York Upstate Medical University, Syracuse, NY 13210, USA. hudsons@upstate.edu
Abstract:
This study tests the hypothesis that reverse transcription polymerase chain reaction (RT-PCR) microarrays can be used to predict the relative sensitivity to induction of apoptosis in breast cancer cells exposed to inhibitors of antiapoptotic Bcl-2 family proteins. Four cell lines, MDA-MB-231 (MDA-231) and MDA-MB-468 (MDA-468), BT-20 and T47-D were screened for relative expression of Bcl-2 family members A1, Mcl-1, Bcl-2, Bcl-xL and Bcl-w mRNA by RT-PCR microarrays and Western analysis. The four cell lines were treated with 1 μmol/L obatoclax (GX15-070) and/or 2 Gy radiation (RT) and monitored for apoptosis after 48 h. Cell lines showing the highest total fold-increase of Bcl-2 family member mRNA, MDA-231 and MDA-468, also showed the highest levels of apoptosis induction (approximately 70% with obatoclax alone and 82% with obatoclax plus RT). Cell lines with little or no increase in Bcl-2 family mRNA (BT-20 and T47-D) showed less apoptosis (30% following treatment with obatoclax and 42% with obatoclax plus RT). RT-PCR arrays can predict the relative apoptosis response of breast cancer cells to the pan Bcl-2 inhibitor obatoclax alone or when combined with radiation.
Insights
Reverse transcription polymerase chain reaction (RT-PCR) microarrays can predict breast cancer cell apoptosis. This method identifies sensitivity to Bcl-2 inhibitors like obatoclax, alone or with radiation.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Breast cancer cells exhibit varying sensitivity to apoptosis-inducing agents.
- The Bcl-2 protein family plays a crucial role in regulating apoptosis.
- Identifying predictive biomarkers for treatment response is essential in breast cancer therapy.
Purpose of the Study:
- To evaluate the utility of RT-PCR microarrays in predicting breast cancer cell apoptosis.
- To assess the correlation between Bcl-2 family mRNA expression and sensitivity to obatoclax and radiation.
Main Methods:
- Four breast cancer cell lines (MDA-MB-231, MDA-MB-468, BT-20, T47-D) were analyzed.
- Reverse transcription polymerase chain reaction (RT-PCR) microarrays were used to quantify Bcl-2 family mRNA expression.
- Cells were treated with obatoclax (a Bcl-2 inhibitor) and/or radiation, and apoptosis was measured.
Main Results:
- Cell lines with higher Bcl-2 family mRNA expression (MDA-231, MDA-468) showed significantly increased apoptosis induction (approx. 70-82%) with obatoclax and radiation.
- Cell lines with lower Bcl-2 family mRNA expression (BT-20, T47-D) exhibited less apoptosis (approx. 30-42%) under the same treatments.
- A strong correlation was observed between Bcl-2 family mRNA levels and apoptosis response.
Conclusions:
- RT-PCR microarrays can effectively predict the relative apoptosis response of breast cancer cells.
- This technique can guide the selection of patients likely to benefit from Bcl-2 inhibitors, such as obatoclax, in combination with radiation therapy.
