Laminin expression by two clones isolated from the colon carcinoma cell line LoVo that differ in metastatic potential and basement-membrane organization.
In the present report we describe the characteristics of 2 clones, E2 and C5, isolated from the human colon adenocarcinoma cell line LoVo. When grafted to immunosuppressed newborn rats, these clones formed tumors that varied with regard to differentiation rate, basement-membrane organization and lung metastatic potential. Production and distribution of laminin by E2, C5 and related tumors was studied by immunohistochemistry with an anti-laminin monoclonal antibody 4C12 (MAb 4C12). In lowly metastatic E2-derived tumors, strong regular stainings were observed which were strictly peri-tumoral and corresponded to the basal lamina. Since the antibody interacted with human laminin (the graft) but not with rat laminin (the host), this result indicated that basement-membrane laminin was supplied mainly by tumor-cell synthesis. In highly metastatic C5-derived tumors, the staining obtained with MAb 4C12 was peri-cellular and unorganized. Laminin synthesis by E2 and C5 cells in sub-cultures or soon after dissociation from explanted tumors was studied by metabolic labelling with 35S-methionine under steady-state conditions followed by immunoprecipitation and SDS-PAGE. High-molecular-weight laminin comprised by disulfide-linked A and B chains, i.e., heterotrimeric laminin, was found in cell lysates and in the secretion medium of cell lines and tumor cells. In addition, B1B2 dimers and free B chains were observed in cell lysates. Quantitatively, laminin expression by E2 and C5 clones or tumor cells was not significantly different. These findings suggest that basement-membrane defects in invasive clone LoVo C5 were not due to laminin under-expression.
Rémy
L
L
INSERM U218, Centre Léon Bérard, Lyon, France.
Lissitzky
J C
JC
Daemi
N
N
Jacquier
M F
MF
Bailly
M
M
Martin
P M
PM
Bignon
C
C
Doré
J F
JF
D000818:Animals; D000831:Animals, Newborn; D001485:Basement Membrane / Q000378:metabolism / Q000473:pathology; D002455:Cell Division; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D016867:Immunocompromised Host; D007797:Laminin / Q000032:analysis / Q000096:biosynthesis*; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D051381:Rats; D014407:Tumor Cells, Cultured
D007797:Laminin