Detection of Soluble Nuclear Matrix Protein (NMP) Released from Apoptotic Nuclei of Human Papillomavirus (HPV) Positive Cell Lines Treated with Cidofovir
摘要
Acyclic nucleoside phosphonates (ANPs), in particular cidofovir, inhibit the growth of rapidly proliferating cells. This phenomenon is mainly observed in HPV-, adenovirus- and SV40-transformed cell lines. We have shown by a cellular DNA fragmentation ELISA and by cell cycle analysis that the process leading to cell death following treatment with ANPs is due to apoptosis (programmed cell death). Apoptosis is associated with changes in several cellular processes. During apoptosis, dense chromatin masses increase in number until the nucleus becomes pyknotic. The skeletal structure for the topological organization of chromatin in the interphase nucleus is NMP, and breakdown of the overall nuclear structure results in the disruption of normal chromosomal nuclear matrix interactions. We have used a sensitive NMP ELISA that demonstrates the release of NMP in a soluble form from the apoptotic nucleus. A direct relationship between the amount of detectable soluble NMP and the number of dead cells was observed when CK-1 cells (HPV-33+) and HeLa cells (HPV-18+) were treated with different concentrations of cidofovir and cytarabine (AraC). Thus, appearance of detectable soluble NMP, one of the products of the segmentation of the nucleus, confirms that the process leading to cell death following treatment with cidofovir is apoptosis.