Visit our Expo - Redox and Inflammation signaling 2012

Session X : Cell death in cancer Poster X, 104
Protein profiling of different human breast cancer cells lines in response to cisplatin
treatment and validation of anti-apoptotic Bcl-2 as a target for enhancing cisplatin
sensitivity
Christina Westmose Yde and Olaf-Georg Issinger
Institute of Biochemistry and Molecular Biology, University of Southern Denmark,
Campusvej 55, 5230 Odense M, Denmark. E-mail: chriswy@bmb.sdu.dk
Clinical problems in the current treatment of breast cancer patients include severe dosedependent
side effects of the compounds used and development of resistance to the treatment.
Therefore, in prospect of improving the current therapy of breast cancer patients it is
important to study the mechanisms behind drug responsiveness. Five different human breast
carcinoma cancer cell lines, MCF-7, MDA-MB-231, MDA-MB-435, HCC-1937 and CAL-
148, were analyzed in respect to sensitivity to the chemotherapeutic compound cisplatin and
dose-dependent drug-induced cell death was measured by reduction in cell viability (WST-1
test) and by poly(ADP)ribose polymerase (PARP) cleavage. While high doses of cisplatin
were required in order to induce cell death in MCF-7 and MDA-MB-231 the cell lines, MDA-
MB-435, HCC-1937 and CAL-148, were sensitive to cisplatin at much lower doses. In order
to identify proteins involved in sensitizing the cells to cisplatin the breast cancer cell lines
were profiled in respect to protein expression levels of a variety signaling proteins. In all cell
lines an increase in cyclin E and a decrease in cyclin D1 was found after cisplatin treatment.
Furthermore, the mitogen-activated protein kinases, ERK and p38, were phosphorylated at
their activating residues when cell were treated with cisplatin. Neither expression of wild type
p53, estrogen receptor status nor activated Akt seemed to be of primary importance in respect
to cisplatin sensitivity, however, an inverse correlation was found between expression of the
anti-apoptotic protein Bcl-2 in the breast cancer cell lines and cisplatin sensitivity. Therefore,
RNA interference was used in order to knock down Bcl-2 protein in MCF-7, which expressed
the highest amount of Bcl-2, and it was found that Bcl-2 siRNA significantly sensitized MCF-
7 to cisplatin.
Hence, our results confirm the anti-apoptotic Bcl-2 as a possible target for increasing the
effect of chemotherapeutic compounds in breast cancer.
- 437 -