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A role for ITAM‐containing proteins in promoting nonhematopoietic cell transformation
Author(s) -
Grande Shan M,
Bernardini Michelle,
Monroe John G
Publication year - 2008
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.22.2_supplement.400
Subject(s) - microbiology and biotechnology , pi3k/akt/mtor pathway , matrigel , cell culture , protein kinase b , cell , chemistry , transformation (genetics) , immunoreceptor tyrosine based activation motif , biology , signal transduction , biochemistry , gene , receptor tyrosine kinase , genetics , sh2 domain
Objective: We previously demonstrated that expression of a non‐viral ITAM‐containing protein is sufficient for transformation of murine fibroblasts and mammary epithelial cells. Our goal was to determine whether this effect was restricted to immortalized cell lines, and to determine the mechanism for ITAM‐mediated transformation of nonhematopoietic cells. Methods: To examine potential transforming properties of ITAM‐containing proteins, we utilized a recombinant protein consisting of ITAM‐containing cytoplasmic regions of the B cell antigen receptor targeted to the plasma membrane (MAHB). Three‐dimensional (3D) Matrigel cultures were used to monitor the consequence of ITAM expression in either primary murine or human (MCF10As) mammary epithelial cells. For inhibitor experiments, drug/vehicle was added at day 3 of culture and replaced every 3 days. Results: Introduction of MAHB into primary mammary epithelial cells disrupted their development in 3D cultures, an effect that was dependent on an intact ITAM and PI3K activation. Expression of MAHB also disrupted the phenotype of MCF10As in 3D cultures as well as the pattern of Akt activation. Phenotypic changes were blocked using inhibitors to PI3K and mTOR. Conclusions: Our results indicate that expression of a non‐viral ITAM‐containing protein can promote the transformation of nonhematopoietic cells. They also suggest that ITAMs can activate some of the same pathways in both lymphocytes and epithelial cells. In particular, we demonstrate that activation of the PI3K/Akt pathway contributes to the disruption of mammary epithelial cell morphology in 3D cultures.