Growth of the human breast cancer cell lines IBH-4, IBH-6 and IBH-7 in nude

BRUZZONE A; VANZULLI S; LUTHY IA

Buenos Aires

Congreso; VII Jornadas Multidisciplinarias de la Sociedad Argentina de Biología; 2005

Sociedad Argentina de Biología

We have developed in our Lab three human breast cancer cell lines which were sensitive to estrogen, progesterone and EGF. The aim of this work was to study their growth in nude mice. 1-2x107 cancer IBH-4, IBH-6 or IBH-7 cells were injected sc into female athymic nude female mice (N:NIH(S)-nu). Mice were treated with estradiol (0.5 mg) pellets, MPA (20 mg) depot or both. Tumors were measured with a Vernier caliper and tumor volume was calculated using the formula: 4/3¥ð*minor radius2*main radius. The three cell lines proved to be tumorigenic. IBH-4 tumors formed poorly differentiated solid carcinomas, with fusocellular components and grew similarly in hormone-treated or untreated mice. They were highly vascularized and had a high mitotic index. The volume reached after 30 days, in absence of hormones, increased with the successive passages (p.) 2668 ¡¾ 290 (1¨¬ p.), 9056¡¾ 1035 (2¡Æ p.) and 7524 ¡¾ 1637 (3¡Æ p.) mm3, p<0.001. Multiple lung metastases were observed in some mice. IBH-6 tumors were poorly differentiated sarcoma-like tumors with a high mitotic index. Tumor size was greater in estradiol-treated mice. The volume reached after 30 days was higher after they were passed in vivo than when inoculated from cell cultures. The tumors frequently invaded the peritoneum and neighboring tissues. Lung, pancreas, lymph nodes and diaphragm metastases were observed. IBH-7 carcinomas only grew in E2-treated mice. Tumors were ductal carcinomas showing slow growth. Metastases were observed in lung and uterus. All tumors were cytokeratin positive and vimentin negative. We conclude that the malignant IBH-4 and IBH-6 cell lines have a different sensitivity to hormones when growing in nude mice and when tested in vitro, whereas the IBH-7 cell line conserved in vivo the estrogen dependence.