Establishment of two nonmetastasizing and one metastasizing rat mammary carcinoma cell lines.

Two continuous rat mammary tumor cell lines have been established in culture from the lymphogenously metastasizing rat mammary carcinoma TMT-081 and one from the nonmetastasizing MT-100 and some of their in vitro and in vivo characteristics studied. Cell line TMT-081-MS was established as a free-floating cell suspension from the metastasis-free spleen of a rat bearing TMT-081 in the ascites form and is characterized by a high level of mammary tissue specific antigen (MTA), an antigen present on lactating or hormonally stimulated rat mammary tissues but not detected on normal mammary tissue. This line metastasizes in the syngeneic host but is rejected by the nude mouse without metastases. Cell line TMT-081-NM is a line derived from the ascites of a rat also bearing TMT-081 ascites. Cell line MT-100-TC is a line derived from the ascites of a rat bearing the ascites form of MT-100. Neither TMT-081-NM nor MT-100-TC has ever shown metastases in the syngeneic host but they are lethal; in the nude mice they grow rapidly, are lethal, and sometimes show hematogenous metastases. Both grow in small clusters and show a low level of MTA. These cell lines have been in continuous culture for a year and have proliferated and maintained their individual in vitro and in vivo growth characteristics during more than 100 consecutive subcultivations.