Pectic-Oligoshaccharides from Apples Induce Apoptosis and Cell Cycle Arrest in MDA-MB-231 Cells, a Model of Human Breast Cancer

Background: The effects of plant products on cancer cells has become a field of major importance. Manysubstancesmay induce apoptosis in anti-cancer treatment. Pectins, a family of complex polysaccharides, andtheir degradation products may for exasmple exert apoptotic effects in cancer cells. Apples and citrus fruits arethe main sources of pectin which can be applied for anti-cancer research. The present study concerned an intactform of pectic-oligoshaccharide named pectic acid (poly galactronic acid). Materials and
Methods: Inhibition ofcell proliferation assays (MTT), light microscopy, fluorescence microscopy (acridin orange/ethidium bromide),DNA fragmentation tests, cell cycle analysis, annexin PI and Western blotting methods were applied to evaluateapoptosis.
Results: The results indicated that pectic acid inhibited cell growth and reduced cell attachment after24h incubation. This did not appear to be due to necrosis, since morphological features of apoptosis were detectedwith AO/EB staining and cell cycling was blocked in the sub-G1 phase. Annexin/PI and DNA fragmentationfindings indicated that apoptosis frequency increased after 24h incubation with pectic acid. In addition, the datashowed pectic acid induced caspase-dependent apoptosis.
Conclusions: These data indicate that apple pectic acidwithout any modification could trigger apoptosis in MDA-MB-231 human breast cancer cells and has potentialto improve cancer treatment as a natural product.