Role of extracellular matrix-cell interaction and epidermal growth factor (EGF) on EGF-receptors and actin cytoskeleton arrangement in infantile pituitary cells

Abstract

Epidermal growth factor (EGF) induces changes in cell morphology, actin cytoskeleton, and adhesion processes in cultured infantile pituitary cells. The extracellular matrix, through integrin engagement, collaborates with growth factors in cell signaling. We have examined the participation of collagen I/III and collagen plus fibronectin in the EGF response of infantile pituitary cells with respect to their cell morphology and actin cytoskeleton. As a comparison, we have used poly-lysine as a substrate. Infantile cells elicit the EGF response when they are associated with extracellular matrix proteins, but no response can be obtained with poly-lysine as the substrate. Cells acquire a flattened shape and organize their actin filaments and vinculin as in focal adhesions. Because the EGF receptor (EGFR) is linked to the actin cytoskeleton in other cells structuring a microdomain in cell signaling, we have investigated this association and substrate adhesion participation in infantile pituitary cells. The proportion of EGFR associated with the actin cytoskeleton is approximately 31%; no difference has been observed between the substrates used. Cells in suspension show actin-associated EGFR, suggesting an association independent of cell adhesion. However, no colocalization of EGFRs with actin fibers has been observed, suggesting an indirect association. Compared with beta(1)-integrin, which is linked to actin fibers through structural proteins, EGFR binds more strongly with the actin cytoskeleton. This study thus shows cell adhesion dependence on the EGF effect in the actin cytoskeleton arrangement; this is probably favored by the actin fiber/EGFR association that facilitates the cell signaling pathways for actin cytoskeleton organization in infantile pituitary cells.

The Metalloprotease ADAMTS8 Displays Antitumor Properties through Antagonizing EGFR–MEK–ERK Signaling and Is Silenced in Carcinomas by CpG Methylation

“…As metalloproteases have been shown involved in tumorigenesis through regulating EGFR signaling (31,32), we investigated the impact of ADAMTS8 on the EGFR signaling pathway. Culturing medium from KYSE150 cells Figure 3.…”

In situ hybridization reveals that type I and III collagens are produced by pericytes in the anterior pituitary gland of rats

“…Kuchenbauer et al (2001) have demonstrated that fibronectin, laminin, and type I collagen inhibit the production of adrenocorticotropic hormone in the corticotroph tumor cell line AtT-20, and that AtT-20 cell proliferation is stimulated by type IV collagen and fibronectin but inhibited by type I collagen and laminin. In addition, morphological changes in infantile rat pituitary cells can be induced by epidermal growth factor in cells cultured on type I and III collagens (Toral et al 2007). Although ECM components might play an important role in the function of the anterior pituitary gland, as mentioned above, little is known about the characteristics of ECM-producing cells in the anterior pituitary gland.…”

Folliculostellate cell interacts with pericyte via TGFβ2 in rat anterior pituitary

“…These collagens are distributed around endocrine cells and capillaries and support tissue structure. With respect to function, type I and/or type III collagens act on anterior pituitary cells to modulate hormone and ECM production (Kuchenbauer et al 2001, Syaidah et al 2013 and alter cellular behaviors (Toral et al 2007, Horiguchi et al 2010. It is generally accepted that fibroblasts and myofibroblasts are collagen-producing cells in many tissues; however, these cells have not been identified in the anterior pituitary gland.…”