Limits...
Regulation of pancreatic cancer cell migration and invasion by RhoC GTPase and caveolin-1.

Lin M, DiVito MM, Merajver SD, Boyanapalli M, van Golen KL - Mol. Cancer (2005)

Bottom Line: Furthermore, inhibition of RhoC or p38 activity in HPAF-II cells leads to partial restoration of cav-1 expression.Cav-1 expression inhibits RhoC GTPase activation and subsequent activation of the p38 MAPK pathway in primary PC cells thus restricting migration and invasion.In contrast, loss of cav-1 expression leads to RhoC-mediated migration and invasion in metastatic PC cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Hematology-Oncology, Department of Internal Medicine, The University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA. liming@yahoo.com

ABSTRACT

Background: In the current study we investigated the role of caveolin-1 (cav-1) in pancreatic adenocarcinoma (PC) cell migration and invasion; initial steps in metastasis. Cav-1 is the major structural protein in caveolae; small Omega-shaped invaginations within the plasma membrane. Caveolae are involved in signal transduction, wherein cav-1 acts as a scaffolding protein to organize multiple molecular complexes regulating a variety of cellular events. Recent evidence suggests a role for cav-1 in promoting cancer cell migration, invasion and metastasis; however, the molecular mechanisms have not been described. The small monomeric GTPases are among several molecules which associate with cav-1. Classically, the Rho GTPases control actin cytoskeletal reorganization during cell migration and invasion. RhoC GTPase is overexpressed in aggressive cancers that metastasize and is the predominant GTPase in PC. Like several GTPases, RhoC contains a putative cav-1 binding motif.

Results: Analysis of 10 PC cell lines revealed high levels of cav-1 expression in lines derived from primary tumors and low expression in those derived from metastases. Comparison of the BxPC-3 (derived from a primary tumor) and HPAF-II (derived from a metastasis) demonstrates a reciprocal relationship between cav-1 expression and p42/p44 Erk activation with PC cell migration, invasion, RhoC GTPase and p38 MAPK activation. Furthermore, inhibition of RhoC or p38 activity in HPAF-II cells leads to partial restoration of cav-1 expression.

Conclusion: Cav-1 expression inhibits RhoC GTPase activation and subsequent activation of the p38 MAPK pathway in primary PC cells thus restricting migration and invasion. In contrast, loss of cav-1 expression leads to RhoC-mediated migration and invasion in metastatic PC cells.

Show MeSH

Related in: MedlinePlus

Interaction of cav-1 and RhoC in BxPC-3 and HPAF-II PC cell lines. A. Aliquots of 500 μg total protein from BxPC-3, HPAF-II and HPAF-II/dnRhoC transfectants were immunoprecipitated with either a monoclonal or polyclonal antibody to cav-1. Proteins were separated by SDS-PAGE, transferred to nitrocellulose and probed with either a RhoC-specific or cav-1 antibody. Normal IgG negative controls are also shown. B. Immunoblot analysis of 50 μg of total protein for total cav-1 expression using a cav-1 specific monoclonal antibody and actin was measured as a loading control. Densitometry was performed on each blot and expression levels were normalized to the actin control. Expression levels are represented as arbitrary units (AU).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC1173138&req=5

Figure 4: Interaction of cav-1 and RhoC in BxPC-3 and HPAF-II PC cell lines. A. Aliquots of 500 μg total protein from BxPC-3, HPAF-II and HPAF-II/dnRhoC transfectants were immunoprecipitated with either a monoclonal or polyclonal antibody to cav-1. Proteins were separated by SDS-PAGE, transferred to nitrocellulose and probed with either a RhoC-specific or cav-1 antibody. Normal IgG negative controls are also shown. B. Immunoblot analysis of 50 μg of total protein for total cav-1 expression using a cav-1 specific monoclonal antibody and actin was measured as a loading control. Densitometry was performed on each blot and expression levels were normalized to the actin control. Expression levels are represented as arbitrary units (AU).

Mentions: Figure 4A are the results of immunoprecipitation assays using either a polyclonal or monoclonal antibody specific for cav-1 followed by immunoblotting for RhoC. Cav-1 and RhoC proteins co-immunoprecipitated in the BxPC-3 cells but not in the HPAF-II cell line. Unexpectedly, the association between cav-1 and RhoC was restored in the HPAF-II/dnRhoC cell line suggesting that inhibition of RhoC activity leads to re-expression of cav-1 protein.


Regulation of pancreatic cancer cell migration and invasion by RhoC GTPase and caveolin-1.

Lin M, DiVito MM, Merajver SD, Boyanapalli M, van Golen KL - Mol. Cancer (2005)

Interaction of cav-1 and RhoC in BxPC-3 and HPAF-II PC cell lines. A. Aliquots of 500 μg total protein from BxPC-3, HPAF-II and HPAF-II/dnRhoC transfectants were immunoprecipitated with either a monoclonal or polyclonal antibody to cav-1. Proteins were separated by SDS-PAGE, transferred to nitrocellulose and probed with either a RhoC-specific or cav-1 antibody. Normal IgG negative controls are also shown. B. Immunoblot analysis of 50 μg of total protein for total cav-1 expression using a cav-1 specific monoclonal antibody and actin was measured as a loading control. Densitometry was performed on each blot and expression levels were normalized to the actin control. Expression levels are represented as arbitrary units (AU).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1173138&req=5

Figure 4: Interaction of cav-1 and RhoC in BxPC-3 and HPAF-II PC cell lines. A. Aliquots of 500 μg total protein from BxPC-3, HPAF-II and HPAF-II/dnRhoC transfectants were immunoprecipitated with either a monoclonal or polyclonal antibody to cav-1. Proteins were separated by SDS-PAGE, transferred to nitrocellulose and probed with either a RhoC-specific or cav-1 antibody. Normal IgG negative controls are also shown. B. Immunoblot analysis of 50 μg of total protein for total cav-1 expression using a cav-1 specific monoclonal antibody and actin was measured as a loading control. Densitometry was performed on each blot and expression levels were normalized to the actin control. Expression levels are represented as arbitrary units (AU).
Mentions: Figure 4A are the results of immunoprecipitation assays using either a polyclonal or monoclonal antibody specific for cav-1 followed by immunoblotting for RhoC. Cav-1 and RhoC proteins co-immunoprecipitated in the BxPC-3 cells but not in the HPAF-II cell line. Unexpectedly, the association between cav-1 and RhoC was restored in the HPAF-II/dnRhoC cell line suggesting that inhibition of RhoC activity leads to re-expression of cav-1 protein.

Bottom Line: Furthermore, inhibition of RhoC or p38 activity in HPAF-II cells leads to partial restoration of cav-1 expression.Cav-1 expression inhibits RhoC GTPase activation and subsequent activation of the p38 MAPK pathway in primary PC cells thus restricting migration and invasion.In contrast, loss of cav-1 expression leads to RhoC-mediated migration and invasion in metastatic PC cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Hematology-Oncology, Department of Internal Medicine, The University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA. liming@yahoo.com

ABSTRACT

Background: In the current study we investigated the role of caveolin-1 (cav-1) in pancreatic adenocarcinoma (PC) cell migration and invasion; initial steps in metastasis. Cav-1 is the major structural protein in caveolae; small Omega-shaped invaginations within the plasma membrane. Caveolae are involved in signal transduction, wherein cav-1 acts as a scaffolding protein to organize multiple molecular complexes regulating a variety of cellular events. Recent evidence suggests a role for cav-1 in promoting cancer cell migration, invasion and metastasis; however, the molecular mechanisms have not been described. The small monomeric GTPases are among several molecules which associate with cav-1. Classically, the Rho GTPases control actin cytoskeletal reorganization during cell migration and invasion. RhoC GTPase is overexpressed in aggressive cancers that metastasize and is the predominant GTPase in PC. Like several GTPases, RhoC contains a putative cav-1 binding motif.

Results: Analysis of 10 PC cell lines revealed high levels of cav-1 expression in lines derived from primary tumors and low expression in those derived from metastases. Comparison of the BxPC-3 (derived from a primary tumor) and HPAF-II (derived from a metastasis) demonstrates a reciprocal relationship between cav-1 expression and p42/p44 Erk activation with PC cell migration, invasion, RhoC GTPase and p38 MAPK activation. Furthermore, inhibition of RhoC or p38 activity in HPAF-II cells leads to partial restoration of cav-1 expression.

Conclusion: Cav-1 expression inhibits RhoC GTPase activation and subsequent activation of the p38 MAPK pathway in primary PC cells thus restricting migration and invasion. In contrast, loss of cav-1 expression leads to RhoC-mediated migration and invasion in metastatic PC cells.

Show MeSH
Related in: MedlinePlus