Search

PDF file - 79K

PDF file - 54K, Molecular determinants of unscheduled mitotic entry

XLSX file - 155K, Proliferation assay EC50 results for MK-1775 in diverse tumor cell lines.

PDF file - 193K, Time course and dose analysis of gemcitabine and MK-1775

PDF file - 112K, Gemcitabine and MK-1775 combination in WiDr cells

PDF file - 108K, Premature mitosis is prevented by p53, p21 and CDK1 activity

PDF file - 306K, Gemcitabine and MK-1775 combination in various breast cancer cell lines

PDF file - 146K, Combined inhibition of CHK1 and WEE1

PDF file - 91K

PDF file - 724K, S1. MK-1775 treatment inhibits proliferation in diverse tumor cell lines. S2. DNA damage induction by MK-1775 treatment requires mitogen stimulation. S3. The MK-1775 response of three sensitive cell lines.

Inhibition of the DNA damage checkpoint kinase WEE1 potentiates genotoxic chemotherapies by abrogating cell-cycle arrest and proper DNA repair. However, WEE1 is also essential for unperturbed cell division in the absence of extrinsic insult. Here, we investigate the anticancer potential of a WEE1 inhibitor, independent of chemotherapy, and explore a possible cellular context underlying sensitivity to WEE1 inhibition. We show that MK-1775, a potent and selective ATP-competitive inhibitor of WEE1, is cytotoxic across a broad panel of tumor cell lines and induces DNA double-strand breaks. MK-1775–induced DNA damage occurs without added chemotherapy or radiation in S-phase cells and relies on active DNA replication. At tolerated doses, MK-1775 treatment leads to xenograft tumor growth inhibition or regression. To begin addressing potential response markers for MK-1775 monotherapy, we focused on PKMYT1, a kinase functionally related to WEE1. Knockdown of PKMYT1 lowers the EC50 of MK-1775 by five-fold but has no effect on the cell-based response to other cytotoxic drugs. In addition, knockdown of PKMYT1 increases markers of DNA damage, γH2AX and pCHK1S345, induced by MK-1775. In a post hoc analysis of 305 cell lines treated with MK-1775, we found that expression of PKMYT1 was below average in 73% of the 33 most sensitive cell lines. Our findings provide rationale for WEE1 inhibition as a potent anticancer therapy independent of a genotoxic partner and suggest that low PKMYT1 expression could serve as an enrichment biomarker for MK-1775 sensitivity. Mol Cancer Ther; 12(8); 1442–52. ©2013 AACR.

PDF file - 101K, CDK1 and cyclin B1 expression levels in breast cancer cell lines