TY - JOUR
T1 - Differential enhancement of breast cancer cell motility and metastasis by helical and kinase domain mutations of class IA phosphoinositide 3-kinase
AU - Pang, Huan
AU - Flinn, Rory
AU - Patsialou, Antonia
AU - Wyckoff, Jeffrey
AU - Roussos, Evanthia T.
AU - Wu, Haiyan
AU - Pozzuto, Maria
AU - Goswami, Sumanta
AU - Condeelis, John S.
AU - Bresnick, Anne R.
AU - Segall, Jeffrey E.
AU - Backer, Jonathan M.
PY - 2009/12/1
Y1 - 2009/12/1
N2 - Class IA (p85/p110) phosphoinositide 3-kinases play a major role in regulating cell growth, survival, and motility. Activating mutations in the p110α isoform of the class IA catalytic subunit (PIK3CA) are commonly found in human cancers. These mutations lead to increased proliferation and transformation in cultured cells, but their effects on cell motility and tumor metastasis have not been evaluated. We used lentiviral-mediated gene transfer and knockdown to produce stable MDA-MB-231 cells in which the endogenous human p110α is replaced with either wild-type bovine p110α or the two most common activating p110α mutants, the helical domain mutant E545K and the kinase domain mutant H1047R. The phosphoinositide 3-kinase/Akt pathway was hyperactivated in cells expressing physiologic levels of helical or kinase domain mutants. Cells expressing either mutant showed increased motility in vitro, but only cells expressing the helical domain mutant showed increased directionality in a chemotaxis assay. In severe combined immunodeficient mice, xenograft tumors expressing either mutant showed increased rates of tumor growth compared with tumors expressing wild-type p110α. However, tumors expressing the p110α helical domain mutant showed a marked increase in both tumor cell intravasation into the blood and tumor cell extravasation into the lung after tail vein injection compared with tumors expressing wild-type p110α or the kinase domain mutant. Our observations suggest that, when compared with kinase domain mutations in a genetically identical background, expression of helical domain mutants of p110α produce a more severe metastatic phenotype.
AB - Class IA (p85/p110) phosphoinositide 3-kinases play a major role in regulating cell growth, survival, and motility. Activating mutations in the p110α isoform of the class IA catalytic subunit (PIK3CA) are commonly found in human cancers. These mutations lead to increased proliferation and transformation in cultured cells, but their effects on cell motility and tumor metastasis have not been evaluated. We used lentiviral-mediated gene transfer and knockdown to produce stable MDA-MB-231 cells in which the endogenous human p110α is replaced with either wild-type bovine p110α or the two most common activating p110α mutants, the helical domain mutant E545K and the kinase domain mutant H1047R. The phosphoinositide 3-kinase/Akt pathway was hyperactivated in cells expressing physiologic levels of helical or kinase domain mutants. Cells expressing either mutant showed increased motility in vitro, but only cells expressing the helical domain mutant showed increased directionality in a chemotaxis assay. In severe combined immunodeficient mice, xenograft tumors expressing either mutant showed increased rates of tumor growth compared with tumors expressing wild-type p110α. However, tumors expressing the p110α helical domain mutant showed a marked increase in both tumor cell intravasation into the blood and tumor cell extravasation into the lung after tail vein injection compared with tumors expressing wild-type p110α or the kinase domain mutant. Our observations suggest that, when compared with kinase domain mutations in a genetically identical background, expression of helical domain mutants of p110α produce a more severe metastatic phenotype.
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U2 - 10.1158/0008-5472.CAN-09-1968
DO - 10.1158/0008-5472.CAN-09-1968
M3 - Article
C2 - 19903845
AN - SCOPUS:71549166652
SN - 0008-5472
VL - 69
SP - 8868
EP - 8876
JO - Cancer Research
JF - Cancer Research
IS - 23
ER -