Related Experiment Video

Updated: May 29, 2026

Analyzing Murine Schwann Cell Development Along Growing Axons
09:46

Analyzing Murine Schwann Cell Development Along Growing Axons

Published on: November 21, 2012

Insulin-like growth factor-binding protein-1 (IGFBP-1) regulates human schwannoma proliferation, adhesion and

S Ammoun1, M C Schmid, L Zhou

  • 1Clinical Neurobiology, Peninsula College for Medicine and Dentistry, Plymouth, UK.

Oncogene
|September 6, 2011
PubMed

Insights

Loss of merlin causes Neurofibromatosis type 2 (NF2) tumors like schwannomas. Researchers found that insulin-like growth factor-binding protein-1 (IGFBP-1) activates pathways that increase schwannoma cell growth and adhesion, offering a potential therapeutic target.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Merlin is a tumor suppressor crucial for preventing mesotheliomas and Neurofibromatosis type 2 (NF2).
  • Loss of merlin function leads to NF2, characterized by tumors like schwannomas, with poorly understood mechanisms of proliferation and adhesion.
  • Schwannoma cells exhibit increased proliferation, cell-matrix adhesion, and reduced apoptosis due to factors like growth factor receptor and integrin overexpression.

Purpose of the Study:

  • To investigate the role of insulin-like growth factor-binding protein-1 (IGFBP-1) in merlin-deficient schwannoma pathogenesis.
  • To elucidate the signaling pathways, including IGFBP-1, integrin β1, and focal-adhesion-kinase (FAK), involved in schwannoma cell proliferation and adhesion.
  • To identify potential therapeutic targets for merlin-deficient tumors.

Main Methods:

  • Utilized an in vitro model of human schwannoma.
  • Employed short hairpin RNA (shRNA) knockdown, small molecule inhibitors, and recombinant IGFBP-1.
  • Analyzed protein expression, activation states, subcellular localization (e.g., nuclear FAK), and pathway signaling (Src/FAK, AKT).

Main Results:

  • Schwannoma cells, unlike normal Schwann cells, overexpress and release IGFBP-1.
  • IGFBP-1 activates the Src/FAK pathway via β1-integrin, enhancing schwannoma cell proliferation and adhesion.
  • Downregulation of phosphatase and tensin homolog (PTEN) in schwannoma cells increases anti-apoptotic AKT activity.
  • Src activation was shown to trigger IGFBP-1 production, and FAK was observed in the nucleus.

Conclusions:

  • The IGFBP-1/integrin β1/Src/FAK signaling axis is critical for merlin-deficient schwannoma development.
  • This pathway significantly contributes to schwannoma cell proliferation and matrix adhesion.
  • Targeting the IGFBP-1/integrin β1/Src/FAK pathway presents a promising therapeutic strategy for merlin-deficient tumors.

More Related Videos

Primary Culture of Human Vestibular Schwannomas10:50

Primary Culture of Human Vestibular Schwannomas

Published on: July 20, 2014

Ex Vivo Culture of Circulating Tumor Cells in the Cerebral Spinal Fluid from Melanoma Patients to Study Melanoma-Associated Leptomeningeal Disease06:25

Ex Vivo Culture of Circulating Tumor Cells in the Cerebral Spinal Fluid from Melanoma Patients to Study Melanoma-Associated Leptomeningeal Disease

Published on: March 29, 2024

Related Concept Videos

Regulation of Angiogenesis and Blood Supply01:24

Regulation of Angiogenesis and Blood Supply

Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits.  Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...
Intracellular Signaling Affects Focal Adhesions01:17

Intracellular Signaling Affects Focal Adhesions

Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
Immunoglobulin-like Cell Adhesion Molecules01:31

Immunoglobulin-like Cell Adhesion Molecules

Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Insulin: The Receptor and Signaling Pathways01:28

Insulin: The Receptor and Signaling Pathways

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
Activation of Integrins01:15

Activation of Integrins

Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.