HeLa cells treated with phytoglycoprotein (150 kDa) were killed by activation of caspase 3 via inhibitory activities of NF-kappaB and AP-1.

The Solanum nigrum Linne (SNL) has been traditionally used as a herbal agent in folk medicine for various cancers in Korea. We found that the SNL glycoprotein consists of carbohydrate (69.74%) and protein content (30.26%), which has mainly the hydrophobic amino acids containing glycine and proline. With respect to its characters, we evaluated the apoptotic effects of glycoprotein isolated from SNL in human cervical cancer cell. In the activity of the apoptotic related proteins [cytochrome c, caspase 8, 3 and poly (ADP-ribose) polymerase (PARP)], the results showed that SNL glycoprotein (50 microg/ml) has a stimulatory effect on cytochrome c release into cytosol, caspase 8, 3 activation and PARP cleavage in HeLa cells. To verify the possible mechanism for apoptotic activity of SNL glycoprotein in HeLa cells, the binding activities of transcription factors (NF-kappaB and AP-1) and nitric oxide (NO) production was evaluated. The activities of NF-kappaB and AP-1 significantly decreased after SNL glycoprotein (50 microg/ml) treatment for 4 h, compare to the control. Interestingly, there was no difference of the DNA binding activity between NF-kappaB and AP-1. Also, nitric oxide (NO) production was significantly declined at 50 microg/ml SNL glycoprotein for 4 h. Therefore, we speculated that SNL glycoprotein exhibits inhibitory effect on HeLa cells via apoptosis, and it may be a potential candidate in field of anticancer drug discovery.