A Role for Polymerase η in the Cellular Tolerance to Cisplatin-Induced Damage

Albertella, Mark R., Green, Catherine M., Lehmann, Alan R. and O'Connor, Mark J. (2005) A Role for Polymerase η in the Cellular Tolerance to Cisplatin-Induced Damage. Cancer Research, 65 (21). pp. 9799-806. ISSN 0008-5472

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Abstract

Mutation of the POLH gene encoding DNA polymerase η (pol η) causes the UV-sensitivity syndrome xeroderma pigmentosum-variant (XP-V) which is linked to the ability of pol η to accurately bypass UV-induced cyclobutane pyrimidine dimers during a process termed translesion synthesis. Pol η can also bypass other DNA damage adducts in vitro, including cisplatin-induced intrastrand adducts, although the physiological relevance of this is unknown. Here, we show that independent XP-V cell lines are dramatically more sensitive to cisplatin than the same cells complemented with functional pol η. Similar results were obtained with the chemotherapeutic agents, carboplatin and oxaliplatin, thus revealing a general requirement for pol η expression in providing tolerance to these platinum-based drugs. The level of sensitization observed was comparable to that of XP-A cells deficient in nucleotide excision repair, a recognized and important mechanism for repair of cisplatin adducts. However, unlike in XP-A cells, the absence of pol η expression resulted in a reduced ability to overcome cisplatin-induced S phase arrest, suggesting that pol η is involved in translesion synthesis past these replication-blocking adducts. Subcellular localization studies also highlighted an accumulation of nuclei with pol η foci that correlated with the formation of monoubiquitinated proliferating cell nuclear antigen following treatment with cisplatin, reminiscent of the response to UV irradiation and further indicating a role for pol η in dealing with cisplatin-induced damage. Together, these data show that pol η represents an important determinant of cellular responses to cisplatin, which could have implications for acquired or intrinsic resistance to this key chemotherapeutic agent.

Item Type: Article
Additional Information: 0008-5472 Journal Article GDSC148
Depositing User: Gee Wheatley
Date Deposited: 19 Mar 2007
Last Modified: 30 Nov 2012 16:51
URI: http://sro.sussex.ac.uk/id/eprint/965
Google Scholar:77 Citations
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