STIMULATORY EFFECT OF RECONSTITUTED BASEMENT-MEMBRANE COMPONENTS (MATRIGEL) ON THE COLONY FORMATION OF A PANEL OF HUMAN LUNG-CANCER CELL-LINES IN SOFT AGAR

Lung cancers have been distinguished into small-cell lung cancer (SCLC ) and non-small cell-lung cancer (NSCLC) types on the basis of their c linical behaviors and their responses to treatment. Moreover, growth o f most SCLC cell lines in liquid culture medium is nonadherent, while that of most NSCLC cell lines is adherent. In this study, we examined the effect of matrigel (reconstituted basement membrane components), w hich is known to have growth-stimulatory activity on various human tum or cell lines in immunodeficient mice, on soft-agar colony formation o f a panel of SCLC and NSCLC cell lines to clarify its mechanism of gro wth stimulation of cancer cells. Matrigel enhanced colony formation of all 9 NSCLC cell lines and 4 of 9 SCLC cell lines. There was a statis tically significant difference (P < 0.01) between colony formations wi th and without matrigel of NSCLC cell lines, but not for SCLC cell lin es. In liquid culture medium, all 9 NSCLC lines and 3 of 9 SCLC lines adhered to plastic dishes, whereas the other SCLC lines did not. Matri gel enhanced colony formation of all 3 adherent-type SCLC lines and 1 of 6 nonadherent-type NSCLC lines. Matrigel enhanced colony formation of both of 2 adherent-type non-lung cancer cell lines and 1 of 2 nonad herent-type leukemia cell lines. Neither transforming growth factor be ta collagen type IV, fibronectin, nor laminin, which are components of matrigel, enhanced colony formation of an NSCLC cell line in soft aga r. The increase in the colony number of the NSCLC cell line by matrige l was abrogated by the protein kinase inhibitors staurosporine and UCN -01.