Novel human breast cancer cell lines IBH-4, IBH-6, and IBH-7 growing in nude mice

Abstract

Breast cancer is the most frequent cancer in women. However, in vivo hormone receptor positive and metas­tatic models are scarce. The aim of the pre­­sent manus­cript was to assess if the novel steroid receptor positive hu­man cell li­nes IBH-4, IBH-6 and IBH-7 developed in our laboratory from primary in­fil­trant duc­tal carcinomas are good mo­dels to study in vivo human breast cancer. Cell lines or tumors were inoculated to nude mice in the presence or ab­­sence of hormone supplementation. Growth was analyzed by ANOVA follo­wed by Tukey-Kra­mer´s test. Steroid hormone expression was assessed by con­focal immuno­fluo­res­cen­ce and Western blotting. The histology of the tu­mors was ana­lyzed. IBH-4 and IBH-6 cells were ino­­­cu­lated to nude mice and 100% of the in­jected mi­ce deve­loped tu­mors in the presence or absence of hor­mo­­ne treat­ment, al­though tamo­xifen inhibited growth. IBH-4 and IBH-6 cell lines in vivo gave rise to poorly diffe­­­ren­tiated carci­no­mas with areas of solid growth and sar­co­­ma­toid areas showing no mor­pho­lo­gical signs of epithe­lial differentiation. Distinct fea­tu­res of ma­lignancy were ob­served. IBH-7 tu­mors in animals receiving estradiol were semi-diffe­ren­­tia­ted ade­no­carcinomas. IBH-7 cells grew only in the pre­­sen­ce of estradiol, but even with hormone addition, the tumor take was 20%. The­se tu­mors me­tas­ta­sized to the uterus and lung and vascular tumor emboli we­re evi­dent. IBH-7 tu­mors were invasive and able to break through the pe­ri­­to­neum. As a conclusion, IBH-4 and IBH-6 are good models for studying tu­mor pro­­gres­sion, whereas IBH-7 is a good model for tumor take, being metastatic and stric­tly estro­gen-dependent.