Cisplatin binds human copper chaperone Atox1 and promotes unfolding in vitro.
Artikel i vetenskaplig tidskrift, 2011

Cisplatin (cisPt), Pt(NH(3))(2)Cl(2), is a cancer drug believed to kill cells via DNA binding and damage. Recent work has implied that the cellular copper (Cu) transport machinery may be involved in cisPt cell export and drug resistance. Normally, the Cu chaperone Atox1 binds Cu(I) via two cysteines and delivers the metal to metal-binding domains of ATP7B; the ATP7B domains then transfer the metal to the Golgi lumen for loading on cuproenzymes. Here, we use spectroscopic methods to test if cisPt interacts with purified Atox1 in solution in vitro. We find that cisPt binds to Atox1's metal-binding site regardless of the presence of Cu or not: When Cu is bound to Atox1, the near-UV circular dichroism signals indicate Cu-Pt interactions. From NMR data, it is evident that cisPt binds to the folded protein. CisPt-bound Atox1 is however not stable over time and the protein begins to unfold and aggregate. The reaction rates are limited by slow cisPt dechlorination. CisPt-induced unfolding of Atox1 is specific because this effect was not observed for two unrelated proteins that also bind cisPt. Our study demonstrates that Atox1 is a candidate for cisPt drug resistance: By binding to Atox1 in the cytoplasm, cisPt transport to DNA may be blocked. In agreement with this model, cell line studies demonstrate a correlation between Atox1 expression levels, and cisplatin resistance.

Humans

genetics

Protein Binding

Copper

metabolism

DNA

Cation Transport Proteins

Biological Transport

pharmacokinetics

chemistry

chemistry

Antineoplastic Agents

genetics

drug effects

metabolism

Binding Sites

metabolism

Neoplasms

Drug Resistance

Molecular Chaperones

chemistry

chemistry

Neoplasm

Protein Structure

Cisplatin

metabolism

Tertiary

drug effects

pharmacokinetics

drug effects

Protein Folding

drug therapy

metabolism

chemistry

Författare

Maria E Palm

Christoph F Weise

Christina Lundin

Gunnar Wingsle

Yvonne Nygren

Erik Björn

Peter Naredi

Magnus Wolf-Watz

Pernilla Wittung Stafshede

Proceedings of the National Academy of Sciences of the United States of America

0027-8424 (ISSN) 1091-6490 (eISSN)

Vol. 108 6951-6

Ämneskategorier

Cancer och onkologi

DOI

10.1073/pnas.1012899108

PubMed

21482801