Identification of WEE1 as a potential molecular target in cancer cells by RNAi screening of the human tyrosine kinome

Breast Cancer Res Treat. 2010 Jul;122(2):347-57. doi: 10.1007/s10549-009-0571-2. Epub 2009 Oct 10.


Breast cancers can be classified into those that express the 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). In order to identify potential molecular targets in breast cancer, we performed a synthetic siRNA-mediated RNAi screen of the human tyrosine kinome. A primary RNAi screen conducted in the triple-negative/basal-like breast cancer cell line MDA-MB231 followed by secondary RNAi screens and further studies in this cell line and two additional triple-negative/basal-like breast cancer cell lines, BT20 and HCC1937, identified the G2/M checkpoint protein, WEE1, as a potential therapeutic target. Similar sensitivity to WEE1 inhibition was observed in cell lines from all subtypes of breast cancer. RNAi-mediated silencing or small compound inhibition of WEE1 in breast cancer cell lines resulted in an increase in gammaH2AX levels, arrest in the S-phase of the cell cycle, and a significant decrease in cell proliferation. WEE1-inhibited cells underwent apoptosis as demonstrated by positive Annexin V staining, increased sub-G1 DNA content, apoptotic morphology, caspase activation, and rescue by the pan-caspase inhibitor, Z-VAD-FMK. In contrast, the non-transformed mammary epithelial cell line, MCF10A, did not exhibit any of these downstream effects following WEE1 silencing or inhibition. These results identify WEE1 as a potential molecular target in breast cancer.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Apoptosis
  • Breast Neoplasms / enzymology*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology
  • Caspase Inhibitors
  • Caspases / metabolism
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Cycle* / drug effects
  • Cell Cycle* / genetics
  • Cell Line, Tumor
  • Cell Proliferation* / drug effects
  • Cell Survival
  • Cysteine Proteinase Inhibitors / pharmacology
  • Female
  • Histones / metabolism
  • Humans
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Kinase Inhibitors / pharmacology
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism*
  • RNA Interference*
  • Receptor, ErbB-2 / analysis
  • Receptors, Estrogen / analysis
  • Receptors, Progesterone / analysis
  • Time Factors


  • Caspase Inhibitors
  • Cell Cycle Proteins
  • Cysteine Proteinase Inhibitors
  • H2AX protein, human
  • Histones
  • Nuclear Proteins
  • Protein Kinase Inhibitors
  • Receptors, Estrogen
  • Receptors, Progesterone
  • ERBB2 protein, human
  • Protein-Tyrosine Kinases
  • Receptor, ErbB-2
  • WEE1 protein, human
  • Caspases