Molecular correlates of sensitivity to PARP inhibition beyond homologous recombination deficiency in pre-clinical models of colorectal cancer point to wild-type TP53 activity

EBioMedicine

Ina A. Eilertsen¹  Peter W. Eide²  Anita Sveen³  Kaja C.G. Berg³  Arild Nesbakken³  Kushtrim Kryeziu⁴  Ragnhild A. Lothe⁴  Marianne G. Guren⁴  Jarle Bruun⁵  Bjarne Johannessen⁵  Jørgen Smeby⁵ 

[1] Department of Oncology, Oslo University Hospital, Oslo, Norway;Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway;K.G. Jebsen Colorectal Cancer Research Centre, Division of Cancer Medicine, Oslo University Hospital, Oslo, Norway;;Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway;

关键词: Colorectal cancer;    PARP inhibition;    homologous recombination deficiency;    TP53;    RAD51;    gene expression;   

DOI  :  

来源: DOAJ

【 摘 要 】

Background: PARP inhibitors are active in various tumour types beyond BRCA-mutant cancers, but their activity and molecular correlates in colorectal cancer (CRC) are not well studied. Methods: Mutations and genome-wide mutational patterns associated with homologous recombination deficiency (HRD) were investigated in 255 primary CRCs with whole-exome sequencing and/or DNA copy number data. Efficacy of five PARP inhibitors and their molecular correlates were evaluated in 93 CRC cell lines partly annotated with mutational-, DNA copy number-, and/or gene expression profiles. Post-treatment gene expression profiling and specific protein expression analyses were performed in two pairs of PARP inhibitor sensitive and resistant cell lines. Findings: A subset of microsatellite stable (MSS) CRCs had truncating mutations in homologous recombination-related genes, but these were not associated with genomic signatures of HRD. Eight CRC cell lines (9%) were sensitive to PARP inhibition, but sensitivity was not predicted by HRD-related genomic and transcriptomic signatures. In contrast, drug sensitivity in MSS cell lines was strongly associated with TP53 wild-type status (odds ratio 15.7, p = 0.023) and TP53-related expression signatures. Increased downstream TP53 activity was among the primary response mechanisms, and TP53 inhibition antagonized the effect of PARP inhibitors. Wild-type TP53-mediated suppression of RAD51 was identified as a possible mechanism of action for sensitivity to PARP inhibition. Interpretation: PARP inhibitors are active in a subset of CRC cell lines and preserved TP53 function may increase the likelihood of response.

【 授权许可】

Unknown