Abstract B40: Evaluation of the combination of AZD2014 and olaparib in pancreatic cancer cells
Authors: Gopinathan Aarthi , Richards Frances M. , Cosulich Sabina , Basu Bristi , Jodrell Duncan I. 
Published: December 2016

The PI3K/Akt/mTOR pathway is frequently activated in human pancreatic ductal adenocarcinoma (PDAC) and in mouse models of Kras-driven pancreatic cancer. In addition, 20-30% of pancreatic cancers may have “unstable” genomes, associated with somatic or germline BRCA mutations, mutations in genes involved in DNA maintenance (eg. PALB2, ATM) or genes not previously associated with DNA maintenance. We therefore evaluated the efficacy of the mTORC1/2 inhibitor AZD2014 and olaparib, as single agents and in combination in vitro in human (MIA PaCa-2 and Capan-1) and murine (K8484: KRASG12D; p53R172H; Pdx1-cre (KPC)) PDAC cell lines. We also assessed the effect of AZD2014 in combination with gemcitabine, and the triple agent combination.

Drug-induced cytotoxicity and cell proliferation were evaluated in 96-well plates, using the high-throughput sulforhodamine B (SRB) assay. The efficacy of 2-drug combinations was assessed by treating cells with serial dilutions of the compounds in an 8X8 grid format. Synergy was assessed using the Bliss Independence model, as implemented in Combenefit software (http://www.cruk.cam.ac.uk/research-groups/jodrell-group/combenefit). Western blotting showed that phosphorylation of Akt, NDRG1, S6 ribosomal protein and 4EBP1 were suppressed by AZD2014. AZD2014 inhibited the growth of all 3 cell lines, with GI50s in the nanomolar range. At the highest AZD2014 concentration, the growth of all 3 cell lines was inhibited at least 70%. Olaparib was ineffective as a single agent in K8484 and MIA PaCa-2 cells, but reassuringly inhibited the growth of Brca2 deficient Capan-1 cells. Synergy was observed in K8484 cells, and mild synergy in MIA PaCa-2 cells, when AZD2014 was combined with gemcitabine. No synergy was observed with the combination of AZD2014 and olaparib in any of the cell lines, although some additivity was observed in Capan-1 cells. When the 3 drugs were combined, higher olaparib concentrations increased cytotoxicity at lower concentrations of AZD2014, however this did not provide any additional benefit, compared to the combination of AZD2014 and gemcitabine at higher concentrations.

Although the combination of AZD2014 and olaparib did not exhibit synergistic activity, AZD2014 showed efficacy as a single agent, and with gemcitabine is a promising combination that warrants further investigation in patients with pancreatic cancer. Further work is required to understand the mechanism of action of this combination, which may also reveal other promising targets to combine with inhibition of mTORC1/2.

This study was funded by the Cancer Research UK New Agents Committee, with compounds supplied by AstraZeneca.

Citation Format: Aarthi Gopinathan, Frances M. Richards, Sabina Cosulich, Bristi Basu, Duncan I. Jodrell.{Authors}. Evaluation of the combination of AZD2014 and olaparib in pancreatic cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B40.