Phenotypic drift of metastatic and cell‐surface properties of mammary adenocarcinoma cell clones during growth in vitro

Abstract

We have examined cell clones obtained from a 13762 mammary adenocarcinoma tumor and its spontaneous lung metastasis for phenotypic stability during serial culture passage in vitro. Two clones that varied markedly in their metastatic properties were chosen for further examination. One of these clones (MTC) obtained from the parental transplanted tumor initially failed to metastasize within 23 days post-injection s.c. but gained the ability to form spontaneous pulmonary metastases after several serial passages in vitro. Another clone (MTLn3) derived from a spontaneous lung metastasis was initially higher metastatic from short-term culture, but lost the potential to form large numbers of spontaneous lung metastases with long-term culture. In contrast to MTA, clone MTLn3 displayed lymph-node metastasis, and the frequency of lymph-node involvement increased when late-passage cultures of MTLn3 cells were assayed in vivo. Both clones from late-passage cultures produced larger tumor sizes at the primary (mammary fat pad) injection sites compared to early passage cells. The morphologies of MTC cells changed with serial tissue culture passage, while the morphologies of MTLn3 cells did not change. The display of fibronectin on MTC cells by immunofluorescence did not change with culture passage; fibronectin was not detected in cultures of clone MTLn3. Fibronectin was also found on MTC cells by cell surface labelling using lactoperoxidase-catalyzed iodination-sodium dodecylsulfate polyacrylamide gel electrophoresis-autoradiography. Iodination of fibronectin on MTC cells did not vary with culture passage, and as in immunofluorescence experiments it was not detected on MTLn3 cells. There was a decrease in exposure of certain cell surface proteins on MTC cells with culture passage, but we did not detect modifications with this procedure that correlated with culture passage of MTLn3 cells. We conclude that prolonged culture in vitro can result in modifications fo metastatic and cell-surface properties of tumor cell clones.

Antigenicity of newly established colorectal carcinoma cell lines

“…Although in the majority of clones this was due to a reduction in expression of all 3 antigens, several clones showed enhanced binding of C14/1/46/10 monoclonal antibody. A similar drift in cell surface properties of tumour cells in vitro was noted by Neri et al, (1981) and is a problem when designing model systems for testing the cytotoxicity of drug-antibody conjugates.…”

Heterogenous expression of cell-surface antigens in normal epithelia and their tumours, revealed by monoclonal antibodies

“…Heppner, 1979;Fidler & Hart, 1982;Owens et al, 1982). The regeneration of heterogeneity in clones shows that this approach is inadequate to capture the full heterogeneity of a tumour (quite apart from the problem of drift in the properties of cloned lines in the long term (Neri & Nicolson, 1981)). Many studies of tumour heterogeneity have been concerned with metastasis -few cells from a tumour form metastases, and attempts have been made to see whether there are sub-populations of tumour cells that metastasize more efficiently (Fidler & Hart, 1982).…”

Mast cells and matrix degradation at sites of tumour invasion in rat mammary adenocarcinoma

“…Since mast cells apparently have the potential to modulate collagenolysis we have also examined and report here the in vitro effects of soluble mast cell products on the collagenolytic behaviour of rat stromal fibroblasts and tumour cells. Ltd., 1986 tained in alpha-modified minimum essential medium (AMEM) supplemented with 10% heat inactivated foetal calf serum, HIFCS, (Grand Island Biological Co., Grand Island, NY) as previously described (Neri & Nicolson, 1981;Neri et al, 1982).…”