Cross-talk between MAP kinase pathways is involved in IGF-independent, IGFBP-6-induced Rh30 rhabdomyosarcoma cell migration

(c) 2010 Wiley-Liss, Inc..

Insulin-like growth factor binding protein-6 (IGFBP-6) inhibits the tumorigenic properties of IGF-II-dependent cancer cells by directly inhibiting IGF-II actions. However, in some cases, IGFBP-6 is associated with increased cancer cell tumorigenicity, which is unlikely to be due to IGF-II inhibition. The mechanisms underlying the contradictory actions of IGFBP-6 remain unclear. We recently generated an IGFBP-6 mutant that does not bind IGFs (mIGFBP-6) to address this issue. Although RD rhabdomyosarcoma cells express IGF-II, we previously showed that mIGFBP-6 promoted migration through an IGF-independent, p38-dependent pathway. We further studied the role of MAP kinases in IGFBP-6-induced migration of Rh30 rhabdomyosarcoma cells, which also express IGF-II. In these cells, mIGFBP-6 induced chemotaxis rather than chemokinesis. Both wild-type (wt) and mIGFBP-6 transiently induced phosphorylation of ERK1/2 and JNK1, but not p38. Inhibition of ERK1/2 phosphorylation completely prevented mIGFBP-6-induced ERK1/2 activation and cell migration, whereas a JNK inhibitor partially prevented migration. Interestingly, p38 pathway inhibition completely prevented mIGFBP-6-induced ERK1/2 and JNK1 activation and migration despite mIGFBP-6 not activating p38. Furthermore, blocking the ERK1/2 pathway also inhibited mIGFBP-6-induced JNK1 activation. In contrast, IGFBP-6 had no effect on Akt phosphorylation and an Akt inhibitor had no effect on migration. These results indicate that IGFBP-6 promotes Rh30 rhabdomyosarcoma chemotaxis in an IGF-independent manner, and that MAPK signaling pathways and their cross-talk play an important role in this process. Therefore, besides decreasing Rh30 cell proliferation by inhibiting IGF-II, IGFBP-6 promotes their migration via a distinct pathway. Understanding these disparate actions of IGFBP-6 may lead to the development of novel cancer therapeutics.

Medienart:

E-Artikel

Erscheinungsjahr:

2010

Erschienen:

2010

Enthalten in:

Zur Gesamtaufnahme - volume:224

Enthalten in:

Journal of cellular physiology - 224(2010), 3 vom: 01. Sept., Seite 636-43

Sprache:

Englisch

Beteiligte Personen:

Fu, Ping [VerfasserIn]
Liang, Guang Jun [VerfasserIn]
Khot, Sahil S [VerfasserIn]
Phan, Robert [VerfasserIn]
Bach, Leon A [VerfasserIn]

Links:

Volltext

Themen:

67763-97-7
EC 2.7.1.-
EC 2.7.1.24
EC 2.7.11.1
EC 2.7.11.24
Enzyme Inhibitors
Extracellular Signal-Regulated MAP Kinases
Insulin-Like Growth Factor Binding Protein 6
Insulin-Like Growth Factor II
Journal Article
Mitogen-Activated Protein Kinase 8
Mitogen-Activated Protein Kinase 9
P38 Mitogen-Activated Protein Kinases
Phosphatidylinositol 3-Kinases
Proto-Oncogene Proteins c-akt

Anmerkungen:

Date Completed 16.08.2010

Date Revised 18.11.2010

published: Print

Citation Status MEDLINE

doi:

10.1002/jcp.22156

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM197732178