Limits...
FAK signaling is critical for ErbB-2/ErbB-3 receptor cooperation for oncogenic transformation and invasion.

Benlimame N, He Q, Jie S, Xiao D, Xu YJ, Loignon M, Schlaepfer DD, Alaoui-Jamali MA - J. Cell Biol. (2005)

Bottom Line: The overexpression of members of the ErbB tyrosine kinase receptor family has been associated with cancer progression.This colocalization requires intact FAK.In summary, distinct FAK signaling has an essential function in ErbB-induced oncogenesis and invasiveness.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Lady Davis Institute of the Sir Mortimer B. Davis Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada.

ABSTRACT
The overexpression of members of the ErbB tyrosine kinase receptor family has been associated with cancer progression. We demonstrate that focal adhesion kinase (FAK) is essential for oncogenic transformation and cell invasion that is induced by ErbB-2 and -3 receptor signaling. ErbB-2/3 overexpression in FAK-deficient cells fails to promote cell transformation and rescue chemotaxis deficiency. Restoration of FAK rescues both oncogenic transformation and invasion that is induced by ErbB-2/3 in vitro and in vivo. In contrast, the inhibition of FAK in FAK-proficient invasive cancer cells prevented cell invasion and metastasis formation. The activation of ErbB-2/3 regulates FAK phosphorylation at Tyr-397, -861, and -925. ErbB-induced oncogenic transformation correlates with the ability of FAK to restore ErbB-2/3-induced mitogen-activated protein kinase (MAPK) activation; the inhibition of MAPK prevented oncogenic transformation. In contrast, the inhibition of Src but not MAPK prevented ErbB-FAK-induced chemotaxis. In migratory cells, activated ErbB-2/3 receptors colocalize with activated FAK at cell protrusions. This colocalization requires intact FAK. In summary, distinct FAK signaling has an essential function in ErbB-induced oncogenesis and invasiveness.

Show MeSH

Related in: MedlinePlus

FAK regulates ErbB-induced cell invasion and metastasis formation that is induced by human breast cancer cells. (A) ErbB-2 expression status examined by Western blot analysis of cell extracts from cells constitutively overexpressing ErbB-2 (SKBR-3 and T47D) and metastatic cell variants (MCF7-M4 and MDA-231-M2) that were isolated in vivo from MCF7 and MDA-231 cells engineered to overexpress ErbB-2. (B) Western blots on cells stably expressing control (bulk) or FAK siRNA. Note that FAK-specific siRNA induced a marked decrease of FAK expression. GAPDH used as an internal control was unaffected. (C) Inhibition of FAK by siRNA reduced cell invasion to a similar level as observed after Src inhibition but not MAPK inhibition. Cells expressing siRNA or treated with PP2 or UO126 were cultured in the upper chamber, whereas HRG was used as a chemoattractant in the lower chamber. Each bar of the graphs represents the mean ± SD of invading cells from three independent experiments. (D) The metastatic MDA-231-M2 cells were implanted into the mammary fat pad. Animals were sacrificed 50 d later, lungs were fixed in Bouin, and surface lung metastases were counted. Each bar represents the mean of five mice ± SEM (error bars). Image is of representative lungs from these experiments.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2171271&req=5

fig7: FAK regulates ErbB-induced cell invasion and metastasis formation that is induced by human breast cancer cells. (A) ErbB-2 expression status examined by Western blot analysis of cell extracts from cells constitutively overexpressing ErbB-2 (SKBR-3 and T47D) and metastatic cell variants (MCF7-M4 and MDA-231-M2) that were isolated in vivo from MCF7 and MDA-231 cells engineered to overexpress ErbB-2. (B) Western blots on cells stably expressing control (bulk) or FAK siRNA. Note that FAK-specific siRNA induced a marked decrease of FAK expression. GAPDH used as an internal control was unaffected. (C) Inhibition of FAK by siRNA reduced cell invasion to a similar level as observed after Src inhibition but not MAPK inhibition. Cells expressing siRNA or treated with PP2 or UO126 were cultured in the upper chamber, whereas HRG was used as a chemoattractant in the lower chamber. Each bar of the graphs represents the mean ± SD of invading cells from three independent experiments. (D) The metastatic MDA-231-M2 cells were implanted into the mammary fat pad. Animals were sacrificed 50 d later, lungs were fixed in Bouin, and surface lung metastases were counted. Each bar represents the mean of five mice ± SEM (error bars). Image is of representative lungs from these experiments.

Mentions: To confirm the relevance of the results in mouse embryonic fibroblasts to human cells, we examined the importance of FAK for cell invasion in a panel of human breast cancer cells, including SKBR3 and T47D cells that overexpress ErbB-2 constitutively, and two metastatic variants of the breast carcinoma cells MDA-231-M2 and MCF7-M4 that were selected in vivo from parental cells overexpressing ErbB-2. Fig. 7 A shows the ErbB-2 status in these cells, which were examined by Western blot analysis, and Fig. 7 B shows the efficiency of siRNA to down-regulate FAK. We next examined the impact of FAK down-regulation on cell invasion by using the Boyden chamber assay on matched control and FAK siRNA cells.


FAK signaling is critical for ErbB-2/ErbB-3 receptor cooperation for oncogenic transformation and invasion.

Benlimame N, He Q, Jie S, Xiao D, Xu YJ, Loignon M, Schlaepfer DD, Alaoui-Jamali MA - J. Cell Biol. (2005)

FAK regulates ErbB-induced cell invasion and metastasis formation that is induced by human breast cancer cells. (A) ErbB-2 expression status examined by Western blot analysis of cell extracts from cells constitutively overexpressing ErbB-2 (SKBR-3 and T47D) and metastatic cell variants (MCF7-M4 and MDA-231-M2) that were isolated in vivo from MCF7 and MDA-231 cells engineered to overexpress ErbB-2. (B) Western blots on cells stably expressing control (bulk) or FAK siRNA. Note that FAK-specific siRNA induced a marked decrease of FAK expression. GAPDH used as an internal control was unaffected. (C) Inhibition of FAK by siRNA reduced cell invasion to a similar level as observed after Src inhibition but not MAPK inhibition. Cells expressing siRNA or treated with PP2 or UO126 were cultured in the upper chamber, whereas HRG was used as a chemoattractant in the lower chamber. Each bar of the graphs represents the mean ± SD of invading cells from three independent experiments. (D) The metastatic MDA-231-M2 cells were implanted into the mammary fat pad. Animals were sacrificed 50 d later, lungs were fixed in Bouin, and surface lung metastases were counted. Each bar represents the mean of five mice ± SEM (error bars). Image is of representative lungs from these experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2171271&req=5

fig7: FAK regulates ErbB-induced cell invasion and metastasis formation that is induced by human breast cancer cells. (A) ErbB-2 expression status examined by Western blot analysis of cell extracts from cells constitutively overexpressing ErbB-2 (SKBR-3 and T47D) and metastatic cell variants (MCF7-M4 and MDA-231-M2) that were isolated in vivo from MCF7 and MDA-231 cells engineered to overexpress ErbB-2. (B) Western blots on cells stably expressing control (bulk) or FAK siRNA. Note that FAK-specific siRNA induced a marked decrease of FAK expression. GAPDH used as an internal control was unaffected. (C) Inhibition of FAK by siRNA reduced cell invasion to a similar level as observed after Src inhibition but not MAPK inhibition. Cells expressing siRNA or treated with PP2 or UO126 were cultured in the upper chamber, whereas HRG was used as a chemoattractant in the lower chamber. Each bar of the graphs represents the mean ± SD of invading cells from three independent experiments. (D) The metastatic MDA-231-M2 cells were implanted into the mammary fat pad. Animals were sacrificed 50 d later, lungs were fixed in Bouin, and surface lung metastases were counted. Each bar represents the mean of five mice ± SEM (error bars). Image is of representative lungs from these experiments.
Mentions: To confirm the relevance of the results in mouse embryonic fibroblasts to human cells, we examined the importance of FAK for cell invasion in a panel of human breast cancer cells, including SKBR3 and T47D cells that overexpress ErbB-2 constitutively, and two metastatic variants of the breast carcinoma cells MDA-231-M2 and MCF7-M4 that were selected in vivo from parental cells overexpressing ErbB-2. Fig. 7 A shows the ErbB-2 status in these cells, which were examined by Western blot analysis, and Fig. 7 B shows the efficiency of siRNA to down-regulate FAK. We next examined the impact of FAK down-regulation on cell invasion by using the Boyden chamber assay on matched control and FAK siRNA cells.

Bottom Line: The overexpression of members of the ErbB tyrosine kinase receptor family has been associated with cancer progression.This colocalization requires intact FAK.In summary, distinct FAK signaling has an essential function in ErbB-induced oncogenesis and invasiveness.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Lady Davis Institute of the Sir Mortimer B. Davis Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada.

ABSTRACT
The overexpression of members of the ErbB tyrosine kinase receptor family has been associated with cancer progression. We demonstrate that focal adhesion kinase (FAK) is essential for oncogenic transformation and cell invasion that is induced by ErbB-2 and -3 receptor signaling. ErbB-2/3 overexpression in FAK-deficient cells fails to promote cell transformation and rescue chemotaxis deficiency. Restoration of FAK rescues both oncogenic transformation and invasion that is induced by ErbB-2/3 in vitro and in vivo. In contrast, the inhibition of FAK in FAK-proficient invasive cancer cells prevented cell invasion and metastasis formation. The activation of ErbB-2/3 regulates FAK phosphorylation at Tyr-397, -861, and -925. ErbB-induced oncogenic transformation correlates with the ability of FAK to restore ErbB-2/3-induced mitogen-activated protein kinase (MAPK) activation; the inhibition of MAPK prevented oncogenic transformation. In contrast, the inhibition of Src but not MAPK prevented ErbB-FAK-induced chemotaxis. In migratory cells, activated ErbB-2/3 receptors colocalize with activated FAK at cell protrusions. This colocalization requires intact FAK. In summary, distinct FAK signaling has an essential function in ErbB-induced oncogenesis and invasiveness.

Show MeSH
Related in: MedlinePlus