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Lani · 12-10-2006, 12:32 AM

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Differentiation of human airway epithelia is dependent on erbB2.

Vermeer PD,
Panko L,
Karp P,
Lee JH,
Zabner J.
Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, 52242, USA.
A clinical case documented a reversible change in airway epithelial differentiation that coincided with the initiation and discontinuation of trastuzumab, an anti-erbB2 antibody. This prompted the investigation into whether blocking the erbB2 receptor alters differentiation of the airway epithelium. To test this hypothesis, we treated an in vitro model of well-differentiated human airway epithelia with trastuzumab or heregulin-alpha, an erbB ligand. In addition, coculturing with human lung fibroblasts tested whether in vivo subepithelial fibroblasts function as an endogenous source of ligands able to activate erbB receptors expressed by the overlying epithelial cells. Epithelia were stained with hematoxylin and eosin and used for morphometric analysis. Trastuzumab treatment decreased the ciliated cell number by 49% and increased the metaplastic, flat cell number by 640%. Heregulin-alpha treatment increased epithelial height and decreased the number of metaplastic and nonciliated columnar cells, whereas it increased the goblet cell number. We found that normal human lung fibroblasts express transforming growth factor-alpha, heparin-binding epidermal-like growth factor, epiregulin, heregulin-alpha, and amphiregulin, all of which are erbB ligands. Cocultures of airway epithelia with primary fibroblasts increased epithelial height comparable to that achieved following heregulin-alpha treatment. These data show that erbB2 stimulation is required for maintaining epithelial differentiation. Furthermore, the mesenchyme underlying the airway epithelium secretes a variety of erbB ligands that may direct various pathways of epithelial differentiation.
PMID: 16489114 [PubMed - indexed for MEDLINE]

another article says her1 is necessary to sense when the epithelial lining is breeched in order to recognize repair is necessary

How lapatinib will affect this (it inhibits both her1 and her2 ) is not known yet

Lack of ciliated cells can cause you to stop filtering out germs before they get further down, lack of differentiation of the airway cells may cause a lack of some secretions perhaps necessary to keep germs from invading I suppose.

12-10-2006, 12:32 AM	#8
Lani Senior Member Join Date: Mar 2006 Posts: 4,782	the original article I cited Links Differentiation of human airway epithelia is dependent on erbB2. Vermeer PD, Panko L, Karp P, Lee JH, Zabner J. Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, 52242, USA. A clinical case documented a reversible change in airway epithelial differentiation that coincided with the initiation and discontinuation of trastuzumab, an anti-erbB2 antibody. This prompted the investigation into whether blocking the erbB2 receptor alters differentiation of the airway epithelium. To test this hypothesis, we treated an in vitro model of well-differentiated human airway epithelia with trastuzumab or heregulin-alpha, an erbB ligand. In addition, coculturing with human lung fibroblasts tested whether in vivo subepithelial fibroblasts function as an endogenous source of ligands able to activate erbB receptors expressed by the overlying epithelial cells. Epithelia were stained with hematoxylin and eosin and used for morphometric analysis. Trastuzumab treatment decreased the ciliated cell number by 49% and increased the metaplastic, flat cell number by 640%. Heregulin-alpha treatment increased epithelial height and decreased the number of metaplastic and nonciliated columnar cells, whereas it increased the goblet cell number. We found that normal human lung fibroblasts express transforming growth factor-alpha, heparin-binding epidermal-like growth factor, epiregulin, heregulin-alpha, and amphiregulin, all of which are erbB ligands. Cocultures of airway epithelia with primary fibroblasts increased epithelial height comparable to that achieved following heregulin-alpha treatment. These data show that erbB2 stimulation is required for maintaining epithelial differentiation. Furthermore, the mesenchyme underlying the airway epithelium secretes a variety of erbB ligands that may direct various pathways of epithelial differentiation. PMID: 16489114 [PubMed - indexed for MEDLINE] another article says her1 is necessary to sense when the epithelial lining is breeched in order to recognize repair is necessary How lapatinib will affect this (it inhibits both her1 and her2 ) is not known yet Lack of ciliated cells can cause you to stop filtering out germs before they get further down, lack of differentiation of the airway cells may cause a lack of some secretions perhaps necessary to keep germs from invading I suppose.