The establishment of two cell lines from a mouse uterine cervical carcinoma (U₁₄) and their metastatic phenotype changes

Abstract

This paper studies the heterogeneity of metastatic potential of murine cervical carcinoma (U₁₄). Two cell lines, P_11–90 and L_10–90, were established from a pulmonary metastatic substrain (U₁₄AP₁₁) and a lymphatic metastatic substrain (U₁₄AL₁₀), which were selected from U₁₄ in vivo after 11 and 10 passages, respectively. The biologic differences between the two cell lines are as follows. (1) The cells of the P_11–90 line grow more rapidly compared with the L_10–90 line. From the 40th passage the medium pH was different. (2) The median number of chromosomes in P_11–90 and L_10–90 was 72 and 64, respectively; the rates of gap aberration were 88% and 78%, respectively. (3) The number of T lymphocytes and T helper lymphocytes in the peripheral blood from hosts with P_11–90 were higher than that of hosts transplanted with L_10–90, but the number of B lymphocytes in the latter was larger than that in the former. (4) The metastatic potential of each cell line partially decreased compared to the relative tumor substrain, but their organ preference still remained and the transplant locations, axillary or footpad, had a prominent influence on their metastatic behavior. To observe the effects of metastatic target organs on the metastatic phenotypes of tumor cells, as well as to explore a method for the establishment and maintenance of the metastatic organ preference of tumor cells, conditioned medium (CM) from pulmonary or lymphatic node diploid cells was added to the culture medium of P_11–90 and L_10–90. Two sublines, P + P_11–90 and Ln + Lon10–90, were thus established. Using stereological methods we found that the majority of P + P_11–90 cells became larger and their nuclei also increased in size compared with their parental lines, but the majority of Ln + L_10–90 cells became smaller in size, though the nuclei were enlarged. The pulmonary metastatic rate and lymphatic metastatic rate of P + P_11–90, as well as the lymphatic metastatic rate of Ln + L_10–90,, were restored dramatically. The results suggest that by taking advantage of the interaction between tumor cells and the CM of host cells the metastatic potential of tumor cell lines can be maintainedin vitro. Our work may offer an experimental model for the manipulation of metastasis of cell lines coming from the same parent strain but with different metastatic potentials. Our study demonstrates that although the specific metastatic tendencies of the cell lines decrease after multiple passages, these propensities are restored after passages with CM from normal lung and lymph node tissue.