ABSTRACT
Although the complex and multifactorial process of tumour growth has been extensively studied for decades, our understanding of the fundamental relationship between tumour growth dynamics and genetic expression profile remains incomplete. Recent studies of tumour dynamics indicate that gene expression in solid tumours would depend on the distance from the centre of the tumour. Since tumour proliferative activity is mainly localised to its external zone, and taking into account that generation and expansion of genetic mutations depend on the number of cell divisions, important differences in gene expression between central and peripheral sections of the same tumour are to be expected. Here, we have studied variations in the genetic expression profile between peripheral and internal samples of the same brain tumour. We have carried out microarray analysis of mRNA expression, and found a differential profile of genetic expression between the two cell subsets. In particular, one major nuclear protein that regulates cell responses to DNA-damaging and stress signals, GADD45alpha, was expressed at much lower levels in the peripheral zone, as compared to tumour core samples. These differences in GADD45alpha mRNA transcription levels have been confirmed by quantitative analysis via real time PCR, and protein levels of GADD45alpha also exhibit the same pattern of differential expression. Our findings suggest that GADD45alpha might play a major role in the regulation of brain tumour invasive potential.
Subject(s)
Brain Neoplasms/metabolism , Brain Neoplasms/pathology , Cell Cycle Proteins/metabolism , Nuclear Proteins/metabolism , Animals , Brain Neoplasms/genetics , Cell Cycle Proteins/genetics , Cell Proliferation , Cyclin-Dependent Kinase Inhibitor p21/genetics , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Gene Expression Profiling , Magnetic Resonance Imaging , Neoplasm Invasiveness , Nuclear Proteins/genetics , Oligonucleotide Array Sequence Analysis , RNA, Messenger/analysis , RNA, Messenger/metabolism , Rats , Rats, Wistar , Transcription, GeneticABSTRACT
PURPOSE: A new technique for stem cells intrapancreatic autotransplantation in rats. BASIC PROCEDURES: Section of a femoral diaphysis and aspirations of the bone marrow in both femoral segments were performed. A Kirschner needle was placed into the femur. Cells were isolated in Ficoll gradients and preserved at 4-6 degrees C. The second day, cells were injected, via aortic celiac trunk, into the pancreas of the same rat. RESULTS: Femoral surgery were well tolerated. Intrapancreatic homing of the injected cells was suggested with methylene blue injection that stained the pancreas, and proved by labeled cells in pancreas sections. Cell counts after Ficoll isolation were 1 x 10(6) +/- 2 x 10(5) ES. CONCLUSIONS: A technique is described for stem cell autotransplantation in rats. First we obtain autologous bone marrow-derived stem cells. Second, we inject the cells in the pancreas of the donor rat. This approach can be applied to experimental diabetes and other pancreatic processes.
