TY - JOUR
T1 - Chromatin structure determines accessibility of a hairpin polyamide-chlorambucil conjugate at histone H4 genes in pancreatic cancer cells
AU - Jespersen, Christine
AU - Soragni, Elisabetta
AU - James Chou, C.
AU - Arora, Paramjit S.
AU - Dervan, Peter B.
AU - Gottesfeld, Joel M.
N1 - Funding Information:
This work was supported by a grant from the National Cancer Institute (CA107311) to J.M.G. and P.B.D.
PY - 2012/6/15
Y1 - 2012/6/15
N2 - We have shown that a specific pyrrole-imidazole polyamide-DNA alkylator (chlorambucil) conjugate, 1R-Chl, alters the growth characteristics of various cancer cell lines in culture, and causes these cells to arrest in the G2/M stage of the cell cycle, without apparent cytotoxicity. This molecule has also shown efficacy in several mouse xenograft models, preventing tumor growth. Previous microarray studies have suggested that members of the histone H4 gene family, H4c and H4j/k, are the primary targets of this molecule, leading to reduced histone mRNA synthesis and growth arrest in cancer cells. In the present study, we examine the effects of 1R-Chl on transcription of other members of the H4 gene family, with the result that mRNA transcription of most genomic copies of H4 are down-regulated by 1R-Chl in a human pancreatic cancer cell line (MIA PaCa-2), but not in a cell line of non-cancerous origin (HEK293 cells). The basis for this differential effect is likely an open chromatin conformation within the H4 genes in cancer cells. Chromatin immunoprecipitation experiments show increased histone acetylation on the histone H4 genes in cancer cells, compared to HEK293 cells, explaining the differential activity of this molecule in cancer versus non-cancer cells.
AB - We have shown that a specific pyrrole-imidazole polyamide-DNA alkylator (chlorambucil) conjugate, 1R-Chl, alters the growth characteristics of various cancer cell lines in culture, and causes these cells to arrest in the G2/M stage of the cell cycle, without apparent cytotoxicity. This molecule has also shown efficacy in several mouse xenograft models, preventing tumor growth. Previous microarray studies have suggested that members of the histone H4 gene family, H4c and H4j/k, are the primary targets of this molecule, leading to reduced histone mRNA synthesis and growth arrest in cancer cells. In the present study, we examine the effects of 1R-Chl on transcription of other members of the H4 gene family, with the result that mRNA transcription of most genomic copies of H4 are down-regulated by 1R-Chl in a human pancreatic cancer cell line (MIA PaCa-2), but not in a cell line of non-cancerous origin (HEK293 cells). The basis for this differential effect is likely an open chromatin conformation within the H4 genes in cancer cells. Chromatin immunoprecipitation experiments show increased histone acetylation on the histone H4 genes in cancer cells, compared to HEK293 cells, explaining the differential activity of this molecule in cancer versus non-cancer cells.
KW - Chlorambucil
KW - Chromatin immunoprecipitation
KW - Gene targeting agent
KW - MIA PaCa-2 cells
KW - Pyrrole-imidazole polyamide
UR - http://www.scopus.com/inward/record.url?scp=84861579192&partnerID=8YFLogxK
U2 - 10.1016/j.bmcl.2012.04.090
DO - 10.1016/j.bmcl.2012.04.090
M3 - Article
C2 - 22607671
AN - SCOPUS:84861579192
SN - 0960-894X
VL - 22
SP - 4068
EP - 4071
JO - Bioorganic and Medicinal Chemistry Letters
JF - Bioorganic and Medicinal Chemistry Letters
IS - 12
ER -