Alpha-bromoacryloyl derivative of distamycin A (PNU 151807): a new non-covalent minor groove DNA binder with antineoplastic activity.
PNU 151807 is a new synthetic alpha-bromoacryloyl derivative of distamycin A. In the present study we investigated the DNA interaction and the mechanism of action of this compound in parallel with the distamycin alkylating derivative, tallimustine. PNU 151807 possesses a good cytotoxic activity in in vitro growing cancer cells, even superior to that found for tallimustine. By footprinting experiments we found that PNU 151807 and tallimustine interact non-covalently with the same AT-rich DNA regions. However, differently from tallimustine, PNU 151807 failed to produce any DNA alkylation as assessed by Taq stop assay and N3 or N7-adenine alkylation assay in different DNA sequences. PNU 151807, like tallimustine, is able to induce an activation of p53, and consequently of p21 and BAX in a human ovarian cancer cell line (A2780) expressing wild-type p53. However, disruption of p53 function by HPV16-E6 does not significantly modify the cytotoxic activity of the compound. Flow cytometric analysis of cells treated with equitoxic concentrations of PNU 151807 and tallimustine showed a similar induction of accumulation of cells in the G2 phase of the cell cycle but with a different time course. When tested against recombinant proteins, only the compound PNU 151807 (and not tallimustine or distamycin A) is able to abolish the in vitro kinase activity of CDK2-cyclin A, CDK2-cyclin E and cdc2-cyclin B complexes. The results obtained showed that PNU 151807 seems to have a mechanism of action completely different from that of its parent compound tallimustine, possibly involving the inhibition of cyclin-dependent kinases activity, and clearly indicate PNU 151807 as a new non-covalent minor groove binder with cytotoxic activity against cancer cells.
Marchini
S
S
Department of Oncology, Istituto di Ricerche Farmacologiche, Mario Negri, Milan, Italy.
Cirò
M
M
Gallinari
F
F
Geroni
C
C
Cozzi
P
P
D'Incalci
M
M
Broggini
M
M
D000818:Animals; D015153:Blotting, Western; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000187:drug effects; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D016213:Cyclins / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D018983:DNA Footprinting; D004214:Distamycins / Q000378:metabolism* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D051379:Mice; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; C494827:Bax protein, mouse; C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004214:Distamycins; D009588:Nitrogen Mustard Compounds; C119510:PNU 151807; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C066900:tallimustine; C030000:stallimycin; D004247:DNA; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases