BACKGROUNDTo explore the possibility of separating and establishing clonal cell subpopulations with different metastatic phenotype from a human lung large cell carcinoma cell line (WCQH-9801), to identify the difference of biological and molecular biology between NL9980 and L9981 cell lines.

METHODSTwo sub-cell lines (NL9980 and L9981) were isolated and established from a human lung large cell carcinoma cell line (WCQH-9801) by the single cell cloning techniques. The RELP, mRNA and protein transcript expression were detected in NL9980 and L9981 cell lines by Southern blot, RT-PCR and Western blot. The biological characteristics of vivo and vitro were determined in NL9980 and L9981 cell lines by MTT, plate, Boyden chamber methods and animal models.

RESULTS(1)Two sub-cell lines, NL9980 and L9981 which had different metastatic phenotype, were successfully isolated and established from a human lung large cell carcinoma cell line (WCQH-9801). (2)The L9981 cell line had LOH of nm23-H1 gene, deletion of mRNA and protein expression of nm23-H1, but the NL9980 cell line had neither LOH of nm23-H1 nor deletion of mRNA and protein expression of nm23-H1. (3)The proliferation, clone formation and vitro invastion of L9981 cell line were significantly higher than those of NL9980 cell line. (4)The tumorigenicity and lung metastatic rate in nude mouse of L9981 cell line were remarkably higher than those of NL9980. (5) No significant difference of the chromosome number was observed between NL9980 and L9981 cell lines.

CONCLUSIONS(1)NL9980 and L9981 cell lines established from a human lung large cell carcinoma cell line have different biological and molecular characteristics. (2)The high invsaion and metastasis ability of L9981 cell line might be related to the LOH of nm23-H1 gene.