RESUMO
OBJECTIVE: Lim1 (Lim homeobox 1) plays an important role during rodent renal development; however, its rolein human kidney development and disease is still unclear. METHODS: We investigated LIM1 expression during human renal development, in dysplastic kidneys and in renal neoplasms using immunohistochemistry. RNA levels in renal carcinomas were determined by quantitative RT-PCR, and the potential roles of LIM1 in mesenchymal-epithelial transition and cell cycle were investigated in a cell culture model. RESULTS: LIM1 was detected in pretubular aggregates, S-shaped and comma-shaped bodies as well as immature glomeruli between 10 and 30 weeks of gestation. Eleven dysplastic kidneys showed no expression of LIM1. In contrast, 12 of 32 nephroblastomas showed nuclear positivity. One regressive nephroblastoma had diffuse expression of LIM1 in tubular structures, all others showed focal positivity in mesenchymal, blastemal and epithelial structures. Renal cell carcinomas revealed no expression of LIM1. Overexpression of LIM1 in a cell culture model led to an increase in KERATIN7 expression but no change in the cell cycle. CONCLUSION: Our study supports the concept of a causative role of LIM1 deficiency in the development of multicystic kidney. In a small subset of nephroblastomas with a more diffuse expression pattern LIM1 might also contribute to the pathogenesis of these lesions.
Assuntos
Neoplasias Renais/metabolismo , Proteínas com Homeodomínio LIM/metabolismo , Rim Displásico Multicístico/metabolismo , Fatores de Transcrição/metabolismo , Tumor de Wilms/metabolismo , Sequência de Bases , Linhagem Celular , Primers do DNA/genética , Humanos , Imuno-Histoquímica , Rim/embriologia , Rim/crescimento & desenvolvimento , Rim/metabolismo , Neoplasias Renais/genética , Neoplasias Renais/patologia , Proteínas com Homeodomínio LIM/deficiência , Proteínas com Homeodomínio LIM/genética , Rim Displásico Multicístico/genética , Rim Displásico Multicístico/patologia , Fator de Transcrição PAX2/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Tumor de Wilms/genética , Tumor de Wilms/patologiaRESUMO
Metabolic reprogramming is a hallmark of cancer. Understanding cancer metabolism is instrumental to devise innovative therapeutic approaches. Anabolic metabolism, including the induction of lipogenic enzymes, is a key feature of proliferating cells. Here, we report a novel tumor suppressive function for adipose triglyceride lipase (ATGL), the rate limiting enzyme in the triglyceride hydrolysis cascade.In immunohistochemical analysis, non-small cell lung cancers, pancreatic adenocarcinoma as well as leiomyosarcoma showed significantly reduced levels of ATGL protein compared to corresponding normal tissues. The ATGL gene was frequently deleted in various forms of cancers. Low levels of ATGL mRNA correlated with significantly reduced survival in patients with ovarian, breast, gastric and non-small cell lung cancers. Remarkably, pulmonary neoplasia including invasive adenocarcinoma developed spontaneously in mice lacking ATGL pointing to an important role for this lipase in controlling tumor development.Loss of ATGL, as detected in several forms of human cancer, induces spontaneous development of pulmonary neoplasia in a mouse model. Our results, therefore, suggest a novel tumor suppressor function for ATGL and contribute to the understanding of cancer metabolism. We propose to evaluate loss of ATGL protein expression for the diagnosis of malignant tumors. Finally, modulation of the lipolytic pathway may represent a novel therapeutic approach in the treatment of human cancer.