Effect of reconstituted basement membrane components on the growth of a panel of human tumour cell lines in nude mice.

Previous reports have indicated that reconstituted basement membrane (matrigel), when co-injected with either established or primary human tumour cells, can improve the growth of subcutaneous xenografts in nude mice. The human adenocarcinoma cell lines A549, SW480, and WiDr, and the human fibrosarcoma cell line HT1080scc2 exhibit varying degrees of tumourigenicity in nude mice. All these lines showed increased tumorigenicity and/or growth rate, together with a change towards a more differentiated tissue morphology, when co-injected with matrigel into nude mice. Experiments using A549 cell line have indicated that the effect of matrigel is concentration-dependent and that increased growth rate is not maintained when xenografts grown with matrigel are passaged into further mice. These results strongly suggest that increased tumour growth results from the improved growth conditions afforded by matrigel, rather than from the selection of subpopulations of the most tumourigenic cells. Increased growth of intracaecal tumours arising from the co-injection of SW480 cells with matrigel, indicate a possible use for matrigel in the development of more relevant animal models using the orthotopic site. Purified laminin significantly increased the growth of sc tumours resultant from co-injection with either WiDr or A549 cells, whereas collagen IV or laminin with entactin showed no such effect. A role for free laminin in the stimulation of cell growth in the absence of an intact basement membrane is discussed.