Cytoskeletal-induced alterations in the adhesion of HT-1080 fibrosarcoma cells to extracellular matrix.
We have investigated the adhesion of the human fibrosarcoma cell line, HT-1080, transfected with glial fibrillary acidic protein (GFAP) to a variety of extracellular matrix macromolecules (ECM) including collagen type IV, laminin, and fibronectin. The GFAP-transfectants demonstrated altered adhesiveness to extracellular matrix substrates when compared to controls. GFAP-positive, heavy metal-induced fibrosarcoma cells were more adherent to plastic and collagen type IV than were the parental or uninduced cells. In contrast, GFAP-positive fibrosarcoma cells were less adherent to laminin- or fibronectin-coated dishes than controls. Time course adhesion studies over 9 days showed that the heavy metal-induced fibrosarcoma cells progressively became more adherent to collagen type IV and less adherent to laminin- or fibronectin-coated dishes than did uninduced cells. However, with the removal of heavy metal from the medium, the HT-1080 fibrosarcoma cells were restored to their original adhesive potential. By phase microscopy, uninduced and induced HT-1080 cells demonstrated different morphological features and remained viable in an anchorage-dependent fashion on collagen type IV as a substrate. By way of contrast, GFAP-induced HT-1080 cells were not particularly viable in monolayer culture and readily detached from laminin as a substrate. The expression of beta1 integrin in GFAP-positive fibrosarcoma cells was decreased following heavy metal induction by Western blot analyses. In contrast, the expression of alpha2 integrin was increased whereas alpha5 integrin was unchanged in HT-1080 cells following the induction of GFAP. Gelatin zymography showed that 72 kDa collagenase was less expressed in GFAP-induced clones than in controls. Our data suggest that the forced expression of the intermediate filament, GFAP, in HT-1080 cells may modulate cell adhesion to different ECM substrates through alterations in expression of integrins.
Murakami
M
M
Department of Neuro-surgery, Kumamoto University School of Medicine, Kumamoto 860, Japan. masseym@s4.kcn..tv.ne.jp
Dirks
P B
PB
Hubbard
S L
SL
Rutka
J T
JT
D015153:Blotting, Western; D002448:Cell Adhesion; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005354:Fibrosarcoma / Q000235:genetics / Q000378:metabolism*; D005780:Gelatin / Q000737:chemistry; D015870:Gene Expression; D005904:Glial Fibrillary Acidic Protein / Q000502:physiology*; D006801:Humans; D007124:Immunoenzyme Techniques; D016023:Integrins / Q000378:metabolism; D008858:Microscopy, Phase-Contrast; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000502:physiology
D016326:Extracellular Matrix Proteins; D005904:Glial Fibrillary Acidic Protein; D016023:Integrins; D005780:Gelatin; D003094:Collagen