Fig. 5.

Tumor growth and metastasis dissemination require Trop-2 cleavage. (A) Tumor growth curves of L murine fibrosarcoma and 293 transformed human kidney cells, transfected with wt Trop-2 or A87-A88 Trop-2. Bars, SEM. N = 4 per experimental group. Subcutaneous tumor growth curves were obtained by weekly measurements of tumor volumes (d² x D/2), followed by normalization on a group-by-group basis, and computation. (B) Boxplot analysis of KM12SM liver metastasis volume. The lowest median in the mutant set of data, together with the lowest max and minimum values of metastasis volume in mutant, processing-less Trop-2 are shown. N = 37 mice were injected with KM12SM/vector control cells, N=34 were injected with the KM12SM/Trop-2 transfectants and N = 13 were injected with the KM12SM/A87-A88 Trop-2 transfectants, i.e. expressing the cleavage-resistant R87-T88 Trop-2 mutant. (C) Individual KM12SM metastasis volume distribution curves. Gray: control metastases; Blue: wt Trop-2 metastases; Red: proteolytic mutant metastases. The distribution and correlated mutant liver metastases versus vector alone control cells and wt Trop-2 transfectants were statistically assessed by Mann-Whitney non-parametric test. This showed a significant reduction of volumes in the mutant transfectant metastases versus wt Trop-2 (P value = 0.0436), consistent with the loss of the Trop-2 activation path. (D) Macroscopic assessment of normal liver, control KM12SM liver metastasis, and of metastasis by wt Trop-2 or proteolytic mutant Trop-2 colon cancer transfectants.