CHARACTERIZATION OF F3II, A SARCOMATOID MAMMARY-CARCINOMA CELL-LINE ORIGINATED FROM A CLONAL SUBPOPULATION OF A MOUSE ADENOCARCINOMA

We characterized a new mammary tumor cell line, F3II, previously estab lished in vitro from a clonal subpopulation of the BALB/c transplantab le mammary adenocarcinoma M3, moderately metastatic to lung. The F3II cell line has been passaged >50 times. It has grown as elongated cells adherent to the bottom of the flask. Cytogenetic studies showed that F3II cultures were nearly triploid. Tumor cells expressed fibronectin and showed high levels of cell-surface urokinase, a key protease in in vasion and metastasis. F3II. cells grew as poorly differentiated, spin dle-cell carcinoma tumors (sarcomatoid carcinomas) with a prominent lo cal invasiveness, a high angiogenic response, and a 90-100% incidence of lung metastases when inoculated s.c. into syngeneic mice. Ultrastru ctural and immunocytochemical analysis revealed characteristic feature s of carcinomas. Our data suggest that F3II is less differentiated and more aggressive than the original tumor line, supporting the notion t hat mammary carcinomas are heterogeneous neoplasms and contain subpopu lations with diverse biologic behavior. The F3II mouse mammary sarcoma toid carcinoma line is a suitable model to examine antiinvasive, antia ngiogenic, and antimetastatic agents. (C) 1996 Wiley-Liss, Inc.