RESUMO
Survivin is a cancer gene implicated in inhibition of apoptosis and regulation of mitosis, but its function in normal cells has remained elusive. Here, we show that transgenic mice expressing survivin in pancreatic islet beta-cells show no changes in cell proliferation, as determined by islet size or islet number. Transplantation of survivin transgenic islets in diabetic recipient mice affords long-term engraftment and stable correction of hyperglycaemia. This involves intrinsic inhibition of beta-cell apoptosis, in vivo, and global transcriptional changes in pancreatic islets with upregulation of stress response genes, antagonists of cytokine signalling and promoters of angiogenesis. These broad cytoprotective functions of survivin in vivo might be beneficial for gene therapy of diabetes.
Assuntos
Apoptose , Diabetes Mellitus/patologia , Diabetes Mellitus/cirurgia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/patologia , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Linhagem Celular , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Regulação da Expressão Gênica , Humanos , Proteínas Inibidoras de Apoptose , Ilhotas Pancreáticas/cirurgia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Associadas aos Microtúbulos/genética , Proteínas Repressoras , SurvivinaRESUMO
Anticancer agents that selectively kill tumor cells and spare normal tissues are urgently needed. Here, we engineered a cell-permeable peptidomimetic, shepherdin, modeled on the binding interface between the molecular chaperone Hsp90 and the antiapoptotic and mitotic regulator, survivin. Shepherdin makes extensive contacts with the ATP pocket of Hsp90, destabilizes its client proteins, and induces massive death of tumor cells by apoptotic and nonapoptotic mechanisms. Conversely, shepherdin does not reduce the viability of normal cells, and does not affect colony formation of purified hematopoietic progenitors. Systemic administration of shepherdin in vivo is well tolerated, and inhibits human tumor growth in mice without toxicity. Shepherdin could provide a potent and selective anticancer agent in humans.
Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Desenho de Fármacos , Fragmentos de Peptídeos/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Proteína do Homeodomínio de Antennapedia , Antimetabólitos Antineoplásicos/química , Antimetabólitos Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Benzoquinonas , Sítios de Ligação/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citocromos c/metabolismo , Inibidores Enzimáticos/farmacologia , Feminino , Fibroblastos/efeitos dos fármacos , Produtos do Gene tat/genética , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Células HeLa , Proteínas de Homeodomínio/genética , Humanos , Proteínas Inibidoras de Apoptose , Lactamas Macrocíclicas , Masculino , Camundongos , Camundongos SCID , Proteínas Associadas aos Microtúbulos/metabolismo , Modelos Moleculares , Mimetismo Molecular , Proteínas de Neoplasias , Proteínas Nucleares/genética , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , Conformação Proteica , Proteínas Proto-Oncogênicas c-bcl-2/genética , Rifabutina/análogos & derivados , Rifabutina/farmacologia , Células-Tronco/efeitos dos fármacos , Survivina , Telomerase/metabolismo , Fatores de Transcrição/genética , Proteína Supressora de Tumor p53/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Gene signatures that predict aggressive tumor behavior at the earliest stages of disease, ideally before overt tissue abnormalities, are urgently needed. To search for such genes, we generated a transgenic model of survivin, an essential regulator of cell division and apoptosis overexpressed in cancer. Transgenic expression of survivin in the urinary bladder did not cause histologic abnormalities of the urothelium. However, microarray analysis revealed that survivin-expressing bladders exhibited profound changes in gene expression profile affecting extracellular matrix and inflammatory genes. Following exposure to a bladder carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine (OH-BBN), survivin transgenic animals exhibited accelerated tumor progression, preferential incidence of tumors as compared with premalignant lesions, and dramatically abbreviated survival. Conversely, transgenic expression of a survivin Thr34-->Ala dominant-negative mutant did not cause changes in gene expression or accelerated tumor progression after OH-BBN treatment. Therefore, survivin expression induces global transcriptional changes in the tissue microenvironment that may promote tumorigenesis. Detection of survivin or its associated gene signature may provide an early biomarker of aggressive tumor behavior before the appearance of tissue abnormalities.
