Differential expression of the LAMB3 and LAMC2 genes between small cell and non-small cell lung carcinomas.
To identify genes differentially expressed between small cell lung carcinoma (SCLC) cells and non-SCLC cells, mRNA differential display was applied to 3 SCLC cell lines and 6 non-SCLC cell lines. The LAMB3 gene was identified as being expressed only in non-SCLC cells and not in SCLC cells. The LAMB3 gene encodes the laminin beta3 chain, which is a unique component of laminin-5. Laminin-5 is a heterotrimer protein consisting of the alpha3, beta3, and gamma2 chains, and another unique component of laminin-5 is the gamma2 chain encoded by the LAMC2 gene. RT-PCR analysis of the LAMB3 and LAMC2 genes in 45 lung cancer cell lines revealed that both the LAMB3 and LAMC2 genes were co-expressed in 21 of 32 non-SCLC cell lines (66%) but only in one of 13 SCLC cell lines (8%). Coexpression of the LAMB3 and LAMC2 genes was also observed in all 4 cases of primary non-SCLC cells examined but not in the corresponding non-cancerous lung cells. Since alpha6beta4 integrin, the specific laminin-5 binding receptor, is known to be expressed only in non-SCLC cells and not in SCLC cells, it was indicated that laminin-5 is a critical microenvironmental factor for the growth of non-SCLC cells but not of SCLC cells. The differences in the expression of integrins and laminins would be critical factors to distinguish SCLC and non-SCLC cells, and such differences might be associated with the unique biological properties of SCLC cells, including metastatic potential and drug sensitivity.
Manda
R
R
Biology, Pathology Divisions, National Cancer Center Research Institute, 1-1, Tsukiji 5-chome, Tokyo, Chuo-ku, 104-0045, Japan.
Kohno
T
T
Niki
T
T
Yamada
T
T
Takenoshita
S
S
Kuwano
H
H
Yokota
J
J
D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D018288:Carcinoma, Small Cell / Q000235:genetics*; D015815:Cell Adhesion Molecules / Q000235:genetics*; D004847:Epithelial Cells / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007797:Laminin / Q000235:genetics*; D008168:Lung / Q000166:cytology / Q000378:metabolism; D008175:Lung Neoplasms / Q000235:genetics*; D014407:Tumor Cells, Cultured; D000097794:Kalinin
D015815:Cell Adhesion Molecules; D007797:Laminin; D000097794:Kalinin; C400567:LAMC2 protein, human