Chui 24_10

The possible anti-proliferation and cell death induction potential of a novel microbial fermentation extract named as oncogen XP-180 (or simply as XP-180) was tested on three human solid tumour carcinoma cell lines (non-small cell lung cancer A549, breast cancer MDA-MB231, liver adenocarcinoma SK-Hep1) and on the acute myelogenous leukaemia KG1a cell line. Anti-proliferative activity of XP180 was observed on all of these cancer cell lines with comparable efficiency and in a dose-dependent manner. Morphological investigation further suggested that common features of apoptosis, including cell shrinkage and rounding, are present in XP-180 treated cells. Loss of adhesion properties of these solid tumour cell lines was observed upon XP-180 incubation. Anchorage-dependent clonogenicity assay on solid tumour cell lines and semi-solid methylcellulose colony formation assay on leukaemia cell line further revealed that XP-180 strongly inhibited the regeneration potential of these cancer cells. Using KG1a as an experimental model system, XP-180 was shown to stimulate the activity of caspase 3, 8 and 9 without significant change in caspase 6 activity. Furthermore, XP180 readily induced collapse of mitochondrial membrane potential after 2 h of incubation. However, the use of the generic caspase specific inhibitor Z-VAD-FMK does not significantly reverse XP-180 mediated cell death. The results obtained suggest that XP-180-mediated cancer cell death could involve mitochondria and both caspase-dependent and -independent pathways. Therefore, XP-180 is an efficient anti-cancer regimen in vitro.