RESUMO
Heat shock proteins (Hsps) are induced in vitro by several cytotoxic drugs; in human breast cancer cells these proteins appear to be involved in anti-cancer drug resistance. The present report was designed to analyze whether chemotherapy affects in vivo the expression of Hsp27, Hsp70, Hsc70 and Hsp90 in breast cancer patients treated with induction chemotherapy and whether these proteins may be determinants of tumor resistance to drug administration. We have analyzed 35 biopsies from breast cancer patients treated with induction chemotherapy. Expression of the Hsps in the tumors was compared with (i) histological and clinical responses to chemotherapy, (ii) tumor cell proliferation measured by proliferating cell nuclear antigen (PCNA) immunostaining and nucleolar organizer regions (AgNORs) staining and (iii) the expression of estrogen and progesterone receptors. We also compared disease-free survival (DFS) and overall survival (OS) with the expression of the Hsps studied. After chemotherapy, nuclear Hsp27 and Hsp70 expression was increased and Hsp70 and Hsc70 cytoplasmic expression was decreased. A high nuclear proportion of Hsp70 in tumor cells (>10%) correlated significantly with drug resistance. We also observed that patients whose tumors expressed nuclear or a high cytoplasmic proportion (>66%) of Hsp27 had shorter DFS. The combination of Hsp27 and Hsp70 levels showed a strong correlation with DFS. Neither the cellular proliferation nor the levels of steroid receptors showed any significant difference before or after drug administration or during follow-up of patients. Our results suggest that Hsp27 and Hsp70 are involved in drug resistance in breast cancer patients treated with combination chemotherapies.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/química , Neoplasias da Mama/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Proteínas de Choque Térmico/análise , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Biópsia , Neoplasias da Mama/patologia , Divisão Celular , Cisplatino/administração & dosagem , Ciclofosfamida/administração & dosagem , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Epirubicina/administração & dosagem , Fluoruracila/administração & dosagem , Proteínas de Choque Térmico HSP70/análise , Humanos , Metotrexato/administração & dosagem , Pessoa de Meia-Idade , Região Organizadora do Nucléolo/patologia , Prognóstico , Antígeno Nuclear de Célula em Proliferação/análise , Coloração pela PrataRESUMO
Human breast cancers may overexpress certain heat shock protein (hsp) family members, proteins which are involved with cell proliferation and differentiation as well as with disease prognosis and drug resistance. Here, we have studied the relationship between the expression of two hsps (hsp27 and hsp70) and the proliferative activity of tumor cells in 40 biopsies from breast cancer patients. Twenty of these tumors were selected for a detailed colocalization study. Immunocytochemistry was done using specific antibodies against hsp27 and hsp70. Cell proliferation was studied analyzing the expression of proliferating cell nuclear antigen (PCNA) (late G1, S, and G2 phases of the cell cycle) and the number of silver-staining nucleolar organizer regions (AgNORs) (G1 phase). The colocalization study revealed a statistically significant inverse correlation between hsp27 expression and cell proliferation in 16/19 (84%) of the cases evaluated by PCNA immunostaining, and in 11/16 (69%) of the cases evaluated by AgNORs. In contrast, a statistically significant positive correlation between hsp70 expression and elevated cell proliferation was seen in almost 85% of the cases evaluated by PCNA staining, and in almost 50% of the cases evaluated by AgNORs. Moreover, in 22% (9/40) of the breast cancer samples examined, hsp70 was clearly associated with the mitotic spindle. A Western blot analysis revealed that hsp70 was coprecipitated with taxol-polymerized tubulin. The association of hsp70 with the mitotic spindle was not clearly noted in lung carcinoma samples (N = 20) or in normal cells displaying elevated mitotic activity. These studies thus demonstrate that in a significant percentage of clinical breast cancers hsp27 overexpression is inversely correlated with cell proliferation, while hsp70 is clearly associated with the mitotic spindle and cell proliferation. These results add evidence to the concept that in human breast cancers hsp27 may be involved in cell growth arrest and increased differentiation while, in contrast, hsp70 may be involved in cell proliferation; further studies will be necessary to elucidate these possible cause-and-effect relationships.
Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico/metabolismo , Proteínas de Neoplasias/metabolismo , Adulto , Idoso , Biópsia , Western Blotting , Divisão Celular/fisiologia , Feminino , Humanos , Pessoa de Meia-Idade , Região Organizadora do Nucléolo , Antígeno Nuclear de Célula em Proliferação/análise , Coloração pela PrataRESUMO
The presence of immunoreactive adrenocorticotropin-releasing hormone (CRH), luteinizing hormone-releasing hormone (LHRH), growth hormone-releasing hormone (GHRH), and somatostatin has been investigated by immunohistochemistry in forty biopsies from breast cancer patients. All of these hypothalamic hormones were found in about 30% of the samples, seen in the cytoplasm or in the nuclei of the tumor cells. Positive immunostaining for the hypothalamic hormones was present in colloid, lobular, and infiltrating ductal carcinomas. There was not a clear relationship between occurrence of staining for the hypothalamic hormones and the histologic grade of tumors or the clinical stage of the disease. Immunoreactive LHRH was more frequently found in breast tumors with estrogen and progesterone receptors. On the other hand, preneoplastic breast lesions expressed mainly somatostatin, while immunoreactivity was absent in normal mammary tissue.