1: Anticancer Drug Des. 1999 Jun;14(3):179-86. 

Effect of ecteinascidin-743 on the interaction between DNA binding proteins and
DNA.

Bonfanti M, La Valle E, Fernandez Sousa Faro JM, Faircloth G, Caretti G,
Mantovani R, D'Incalci M.

Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Milan,
Italy.

Ecteinascidin-743 (ET-743) is a tetrahydroisoquinoline alkaloid isolated from
Ecteinascidia turbinata, a tunicate growing in mangrove roots in Caribbean. It
has been shown to bind in the minor groove of DNA forming covalent adducts by
reaction of the N2 of guanine with the carbinolamine moiety. We investigated
ET-743 ability to inhibit the binding of different transcription factors to
their consensus sequences by using gel shift assays. We have selected three
types of factors: (i) oncogene products such as MYC, c-MYB and Maf; (ii)
transcriptional activators regulated during the cell cycle as E2F and SRF; and
(iii) general transcription factors such as TATA binding protein (TBP), Sp1 and
NF-Y. We observed no inhibition of the binding of Sp1, Maf, MYB and MYC.
Inhibition of DNA binding was observed for TBP, E2F, SRF at ET-743
concentrations ranging from 50 to 300 microM. The inhibition of binding of NF-Y
occurs at even lower concentrations (i.e. 10-30 microM) when the recombinant
subunits of NF-Y are preincubated with the drug, indicating that the inhibition
of NF-Y binding does not require previous ET-743 DNA binding. Since NF-Y is a
trimer containing two subunits with high resemblance to histones H2B and H2A, we
have investigated the effect of ET-743 on nucleosome reconstitution. ET-743
caused a decrease of the nucleosomal band at 100 nM, with the complete
disappearance of the band at 3-10 microM. These data suggest that the mode of
action of this novel anticancer drug is related to its ability to modify the
interaction between some DNA binding proteins and DNA.

PMID: 10500494 [PubMed - indexed for MEDLINE]


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