RESUMO
Taxanes are approved for the treatment of breast cancer that has spread to the lymph nodes, following surgery and doxorubicin containing chemotherapy. Taxanes have improved the survival of breast cancer patients, especially in estrogen receptor (ER) negative population in clinical settings. This time we examined the relationship between chemosensitivity to Taxanes and expresson of ERalpha in breast cancer cell lines. In vitro effects of paclitaxel in 4 ER-positive and 3 ER-negative breast cancer cell lines were investigated by MTT assay. We also investigated members of Bcl-2 family by Western blotting and RT-PCR to clarify their role in paclitaxel resistance both in ER-positive and in ER-negative cells. ER-negative cell lines were more sensitive to paclitaxel than ER-positive cells. ER-negative KPL-4 and ZR-75-30 cells, which were sensitive to paclitaxel, became resistant when they were treated with demethylation agent, 5-aza-2'-deoxycytidine. Analysis of proapoptotic (Bax) and antiapoptotic (Bcl-2) molecules suggested that Bcl-2 is likely to have a role in the resistance of ER-positive cells. Bcl-2 expression was increased in a time-dependent manner after treatment of ER-positive cell lines with estrogen (E2). On the other hand, Bcl-2 was not detected in ER-negative cell lines. However, no significant difference was detected for Bax mRNA levels before and after E2 treatment in ER-positive and negative cell lines. Activation of ER gene expression in ER-negative KPL-4 cells by 5-aza-2'-deoxycytidine resulted in up-regulation of Bcl-2 mRNA. To support our data, we examined paclitaxel sensitivity in ER-negative MDA-MB-231 and ER stable transfectant cells S30 and JM6. This experiment also showed ER-negative cells were sensitive to paclitaxel but ER-positive cells were resistant to it. These results suggest that ER influenced chemosensitivity to paclitaxel through regulation of Bcl-2 family and regulation of the pathway may be crucial to increase the efficacy of taxanes in ER-positive breast cancer.
Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica , Genes bcl-2 , Paclitaxel/uso terapêutico , Receptores de Estrogênio/fisiologia , Apoptose , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Estradiol/farmacologia , Feminino , Humanos , Receptores de Estrogênio/efeitos dos fármacos , Receptores de Estrogênio/genéticaRESUMO
Cell motility is involved in physiological and pathological processes such as the invasion and migration of cells. c-Jun N-terminal kinase (JNK) cascades are involved in the invasion and metastasis of cancer cells. However, little is known about the downstream signaling of JNK. In the present study, we used small interfering RNA (siRNA) directed against JNK1 to reduce its expression. We used microarray techniques to compare the gene expression profiles of epidermal growth factor (EGF)-stimulated HeLa cells with and without JNK1 siRNA treatment. We identified a JNK1 target gene, myosin phosphatase-Rho interacting protein (M-RIP). RNA interference-mediated inhibition of JNK1 strongly inhibited M-RIP mRNA expression induced by EGF, as well as the invasion of HeLa cells. In addition, M-RIP siRNA-treated cells showed significantly reduced invasive activity. Thus, a functional analysis of JNK1 and M-RIP with RNA interference reveals a critical role for this cascade in the invasive behavior of cancer cells.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Movimento Celular/fisiologia , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Invasividade Neoplásica , Neoplasias/metabolismo , Neoplasias/patologia , Transdução de Sinais/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Fator de Crescimento Epidérmico/metabolismo , Fator de Iniciação 4E em Eucariotos/metabolismo , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Perfilação da Expressão Gênica , Células HeLa , Humanos , Proteína Quinase 8 Ativada por Mitógeno/genética , Neoplasias/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismoRESUMO
AIMS: This study assessed the techniques of the free jejunal graft for the reconstruction of hypopharynx or cervical esophagus and discussed the main aspects related to those procedures. METHODS AND RESULTS: By using free jejunal grafts, we reconstructed 54 hypopharyngeal and cervical esophageal cancers. In this study, 23 out of 54 patients had a malignant tumor located in the hypopharynx and 31 in the cervical esophagus (27 primary cases and four secondary cases). Despite the multi-step and time-consuming procedure, we did not incur any trans-operative complication. Furthermore, we undertook the larynx preserving cervical esophagectomy and free jejunal graft reconstruction in six patients with cervical esophageal cancer, and those patients acquired a good quality of life. CONCLUSION: For the reconstruction of hypopharynx or cervical esophagus, the free jejunal graft is a very useful technique and improves the patient's quality of life.