Detection of Chemotherapy-Induced Apoptosis in Human Breast Cancer

Abstract

Caspase-cleaved keratin 18 (K18) is used as a biomarker of apoptosis to measure chemotherapy-induced cell death. The M30-FITC antibody can be used as a method of detection for caspase-cleaved K18, giving it potential as a prognostic and predictive tool in cancer treatment. This study tests the M30-FITC antibody for use with the human breast cancer cell lines MCF7, SKBR3, and MDA-MB-231 in flow cytometry, with the goal of optimizing the M30-FITC assay for use in human whole blood. The assay was evaluated for use with two different apoptotic pathways: first induced by the chemotherapy docetaxel (Taxotere), and then by the tumor inhibitor staurosporine. Analysis indicates that the M30-FITC antibody requires a specific caspase cleavage product to be produced during apoptosis, which the mechanism of docetaxel-induced apoptosis (mitotic catastrophe) does not appear to produce. Staurosporine treatment appears to induce apoptosis in a manner compatible for use with the M30 antibody, and is sufficient to induce apoptosis in MCF7, SKBR3, and MDA-MB-231. These treated cells are also suitably detected in spiked human whole blood, indicating the potential for clinical relevance of the assay.