Z Gastroenterol 2020; 58(01): e40-e41
DOI: 10.1055/s-0039-3402209
Poster Visit Session IV Tumors: Saturday, February 15, 2020, 8:30 am – 09:15 am, Lecture Hall P1
Georg Thieme Verlag KG Stuttgart · New York

KRAS-mutated intrahepatic cholangiocarcinoma shows preferential sensitivity towards PARP-1-based interventions

FL Mahn
1   University Medical Center of the Johannes Gutenberg University, I. Deparment of Internal Medicine, Mainz, Germany
,
D Castven
1   University Medical Center of the Johannes Gutenberg University, I. Deparment of Internal Medicine, Mainz, Germany
,
SP Pereira
1   University Medical Center of the Johannes Gutenberg University, I. Deparment of Internal Medicine, Mainz, Germany
,
M Hartmann
1   University Medical Center of the Johannes Gutenberg University, I. Deparment of Internal Medicine, Mainz, Germany
,
J Fahrer
2   Technical University Kaiserslautern, Department of Chemistry – Food Chemistry and Toxicology, Kaiserslautern, Germany
,
JB Andersen
3   University of Copenhagen, Biotech Research & Innovation Center, Copenhagen, Denmark
,
MS Matter
4   Universitätsspital Basel, Insitute of Pathology, Basel, Switzerland
,
T Gaiser
5   University Medical Center, Institute of Molecular Pathology, Mannheim, Germany
,
S Rössler
6   University Hospital, Institute of Pathology, Heidelberg, Germany
,
PR Galle
1   University Medical Center of the Johannes Gutenberg University, I. Deparment of Internal Medicine, Mainz, Germany
,
JU Marquardt
1   University Medical Center of the Johannes Gutenberg University, I. Deparment of Internal Medicine, Mainz, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
03 January 2020 (online)

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Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive malignancy of the biliary tract and characterized by its profound genetic heterogeneity. Activating KRAS mutations rank among the most abundant genetic alterations and the presence of this genetic alteration is associated with early recurrence, poor therapeutic response and reduced overall survival in iCCA. In preliminary experiments we found that inhibition of DNA damage response protein Poly (ADP-ribose) polymerase 1 (PARP-1) reduces survival of KRAS-mutated iCCA cell lines; though the exact mechanisms of PARP-1 in cholangiocarcinogenesis are still unknown.

CRISPR/Cas9-mediated knockout and treatment with PARP-1-inhibitor AZD2281 were conducted in several KRAS-mutated and non-mutated iCCA cell lines as well as in patient-derived primary cells. Assessment of PARP-1 knockout and inhibition on tumorigenic potential was analyzed by colony and sphere formation. RNA Sequencing was employed to further analyze underlying molecular pathways.

A significant upregulation of PARP-1, as well as enrichment of a gene set related to PARP-1 activation, was observed in iCCA tissue and RNASeq data compared to control, indicating a potential role of a PARP-1-signature in cholangiocarcinogenesis. Interestingly, a higher PARP-1 expression was also demonstrated in KRAS-mutated compared to non-mutated cell lines. Consistently, knockout of PARP-1 showed a preferential effect in KRAS-mutated cell lines and led to a 40 – 45% reduction in colony and sphere formation and sensitized KRAS-mutated cells towards DNA double-strand break-inducing agents. In addition, KRAS-mutated cell lines showed a significantly higher sensitivity to treatment with the PARP-1-inhibitor. RNA Sequencing analysis revealed differential expression of DNA damage response pathways as well as other cellular pathways known to be affected by PARP-1, e.g. apoptosis.

These investigations establish a therapeutic role for PARP-1 inhibition in iCCA. The preferential sensitivity of KRAS-mutated cell lines for PARP-1-based interventions suggests a potential interaction and might be clinically relevant.