Hsp27 and Hsp70 in serial biopsies from breast cancer patients treated with doxorubicin

LAURA M. VARGAS ROIG; PEDRO DAGUERRE; MARCELA LEUZZI; FRANCISCO E. GAGO; SILVINA B. NADIN; MA LAZZARO; DR CIOCCA

Mendoza, Argentina

Workshop; 3RD International Workshop on Molecular Biology of Stress Responses; 2001

International Cell Stress Society

Heat shock proteins (Hsps) may be expressed in human tumors such as in breast cancer, where some of the Hsps family members have been studied as prognostic markers. There is in vitro evidence that Hsps may be involved in doxorubicin resistance. In a previous study, we observed that the administration of doxorubicin, 5-fluoruracil and cyclophosphamide changed the expression of Hsp27 and Hsp70 in biopsies of breast cancer patients. We observed increased Hsp27 and Hsp70 nuclear expression and a significant decrease in the cytoplasmic content of Hsp70. These changes were relatively late events because the post-chemotherapy biopsies were taken approximately 21 days after the last cycle of induction therapy. In the present study, we decided to evaluate the expression of Hsp27 and Hsp70 in serial biopsies from a more homogeneous group of breast cancer patients. The study involved patients with locally advanced disease treated only with doxorubicin during 4 cycles before the surgery as the initial treatment. The serial biopsies were taken at pre-chemotherapy, at days 1, 3, 7, 21, and at surgery. Forty two patients entered into this protocol, after surgery the patients received 6 cycles of cyclophosphamide, methotrexate, and 5-fluorouracil. In the invasive tumors, we found that the increased nuclear expression of Hsp27 and Hsp70 was a relatively late event, since it was significant at surgery. No significant changes were noted in the cytoplasmic content of both Hsps. It is of interest to note that some tumor cells showed membrane expression of Hsp27 and Hsp70. We also examined the other cells that were exposed to doxorubicin, the normal mammary and connective tissue cells and the non invasive tumor cells in situ carcinomas). In normal breast epithelium, cytoplasmic and nuclear expression of Hsp27 was lower than in the invasive tumor, specially at surgery. In in situ carcinomas, Hsp27 cytoplasmic expression was higher than in the invasive tumor cells reaching statistical significant differences up to day 7, at surgery the levels were similar to found in invasive tumor cells. In normal breast epithelium, nuclear Hsp70 content increased at days 1 and 3 and decreased at days 7 and 21, but at surgery nuclear Hsp70 was increased. This dynamics was not seen in tumor cells. We also analyzed the expression of Hsps in blood vessels, Hsp27 and Hsp70 in endothelium increased shortly after chemotherapy and then decreased. We observed the expression of Hsps in stroma fibroblasts and in lymphoid tissue. After chemotherapy we noted an increase in the expression of Hsp27 and Hsp70 specially in the ?activated? fibroblasts (large cells). We observed more expression of Hsp70 than Hsp27 in the cytoplasm of lymphocytes and plasma cells, but always in a lower percentage (