Anticancer and chemosensitization effects of Wee‐1 kinase inhibitor Adavosertib (MK‐1775; AZD‐1775) in breast cancer cell lines

Abstract

Current breast cancer classification included cells that express estrogen (ER) and progesterone (PR) receptors, those with ERBB2 (HER‐2/Neu) amplification, and those without expression of ER, PR, or amplification of ERBB2 (referred to as triple‐negative or basal‐like breast cancer). Triple negative breast cancers (TNBC) are generally more difficult to treat, are known to be more aggressive, and with poor prognosis. Several molecular mechanisms have been identified as potential targets for the development of drugs to treat breast cancer including cell cycle checkpoints kinases. The G2/M cell‐cycle protein tyrosine kinase, Wee‐1, plays a crucial role in the checkpoint arrest for DNA repair before mitotic entry. Under normal conditions, cells repair damaged DNA during G1 arrest; however, cancer cells often have a deficient G1/S (p53) checkpoint and depend on a functional G2/M checkpoint for DNA repair. Adavosertib is a well‐characterized Wee‐1 kinase inhibitor with significant evidence supporting its potential use as an anti‐cancer and/or chemosensitizer drug. Working hypothesis proposed for this project was that use of Wee‐1 kinase inhibitors in breast cancer cells can result in profound and significant anticancer and chemosensitization effects. In order to test this hypothesis, we performed a series of dose‐response experiments using a well‐known DNA‐Damaging agent (DNA‐dt: Cisplatin) alone and/or in combination with Adavosertib. Cytotoxic effects of these treatments were evaluated with the MDA‐MB‐231 (TNBC cells) and the non‐tumorigenic MCF10A, as our in‐vitro cell model systems, and the 384‐well plate/96 hours/resazurin (AlamarBlue) cell proliferation assay. Analysis of these results included determination of half‐maximal inhibitory or effective concentration (IC50 or EC50) for each drug treatment and/or combination; and the nature of these interactions (synergy, additivity, antagonism) was determined with the open‐access software CompuSyn, Combenefit, and SynergyFinder. Analysis of the potential for interactions of cisplatin and Adavosertib in MDA‐MB‐231 indicated significant synergism as illustrated by surface and matrix synergy plots, combination index determinations, and isobolograms. However, no significant synergistic interactions were observed when these two drugs are combined in the non‐tumorigenic MCF10A cells. Finally, studies designed to evaluate the possibility that these synergistic effects can also be extended to the levels of expression of several biochemical markers (including pCDC2 and γH2AX) and cell cycle duration are currently underway. These preliminary results are consistent with a potential role of Wee‐1 kinase inhibitors like Adavosertib as anticancer and/or chemosensitizer agents against triple‐negative or basal‐like breast cancer cells.