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Small Molecule Inhibition of MEKK2 Signal Transduction in Cancer Cells
Author(s) -
Noll Jessica,
Scott John E.,
Cuevas Bruce
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.936.4
Subject(s) - cancer research , cancer , metastasis , cancer cell , chemistry , signal transduction , kinase , reporter gene , breast cancer , in vitro , medicine , gene expression , gene , biochemistry
Most cancer patient deaths are due to secondary tumors called metastases that are frequently resistant to therapy. Effective treatment options for metastatic cancer are very limited; therefore the development of new drugs to treat metastases is necessary to improve cancer patient survival. An enzyme critical to metastases can be utilized as a potential therapeutic target if a corresponding small‐molecule inhibitor can be identified and optimized. Our group has demonstrated that the protein kinase, MEKK2, is required for xenograft breast tumor growth and metastasis. We screened small molecule libraries for potential MEKK2 inhibitors and identified several lead compounds that inhibit MEKK2 in vitro that could be modified as future cancer therapeutics. In this work, we examined how these lead compounds affect MEKK2‐dependent functions of tumor cells in culture and if that effect could be extended as a potential therapeutic. Four analogues of one hit were further developed as potential lead compounds (referred to as #1, #2, 82A, and 527), and then we determined whether exposure to the compounds inhibited MEKK2‐dependent tumor cell functions of ERK5 activation, cell migration, and gene expression. We investigated ERK5 pathway activation by ERK5 electrophoretic mobility shift, and MEKK2‐dependent gene expression was analyzed via luciferase‐based reporter assays of NFκB and AP‐1 activation. A modified wound assay was developed to measure velocity in correspondence to cell migration. We discovered that 10μM 82A significantly reduced MEKK2‐dependent NFκB and AP‐1 reporter activity, blocked MEKK2‐dependent ERK5 phosphorylation, and inhibited breast tumor cell migration. Taken together, our data strongly suggest that the 82A lead compound significantly inhibits multiple known MEKK2‐dependent cellular functions. We conclude that the 82A small‐molecule is a suitable lead molecule that can be developed into novel therapeutic MEKK2 inhibitors for treatment of cancer metastases and other MEKK2‐dependent diseases. Support or Funding Information This work was supported by a grant from the National Institutes of Health (NIH) and the American Society for Pharmacology and Experimental Therapeutics (ASPET).