Jarin Kramyu. Elucidation of apoptotic pathway in human breast cancer, MCF-7 cell, induced by VR-3848 isolated from euphobiaceae . Master's Degree(Microbiology). Mahidol University. : Mahidol University, 2006.
Elucidation of apoptotic pathway in human breast cancer, MCF-7 cell, induced by VR-3848 isolated from euphobiaceae
Abstract:
VR-3848 is a plant-derived active compound purified from Euphobiaceae.
Previous studies reported that this compound could inhibit various cancer cell
proliferation such as lung (LU-1), breast (BCA-1), colon (COL-1), mouth epidermoid
carcinoma (KB), and mouse lymphoid neoplasm (P388). VR-3848 also inhibits the
growth of human breast cancer cell, MCF-7. This cancerous cell lacks functional
caspase-3, which is believed to act as principal caspase. Lack of this enzyme
significantly contributes to chemotherapeutic resistance. Growth of MCF-7 cells was
inhibited by VR-3848 in a dose-dependent manner. The GI50 value was 8.20 nM. VR-
3848 treated MCF-7 displayed elevated levels of apoptosis as demonstrated by DAPI
staining and DNA fragmentation pattern. The DAPI nuclear-stained count showed
6.12%, 16.86%, 31.02%, and 49.06% of apoptosis at 6, 12, 18, and 24 hours,
respectively, after drug treatment. In addition, DNA laddering patterns were shown at
18 hours and more clearly visualized at 24, 36, and 48 hours. To elucidate the
apoptosis cell death pathway induced by VR-3848, we used cDNA analysis as a tool.
The result from 205 apoptosis-related gene expression patterns of VR-3848 treated
MCF-7 cell revealed that apoptosis was mediated via three different pathways, which
were the receptor-mediated, the mitochondria-dependent and the ER-stress pathways.
The mitochondrial pathway was confirmed by detection of the high level of AIF
released from the mitochondria. The up-regulation of caspase-10 and caspase-8 at the
initial time point was also observed. Moreover, it was shown that treatment of VR-
3848-treated cells with caspase-10 and caspase-8 specific inhibitor can protect cell
death by apoptosis so that these data support the idea of receptor-ligand mediated
pathway. Moreover, the array results suggested ER-stress associated apoptosis gene.
This ER-stress associated apoptosis pathway was confirmed by the upregulation of
GADD153 gene and caspase-12 in the drug treatment group by PCR and western blot
analysis. These mechanistic studies provide evidence that VR-3848 may be one of an
anticancer lead compound targeting human breast cancer cells.