BioProject

Mice that develop benign cartilage lesions due to overexpression of Gli2 in chondrocytes developed lesions similar to chondrosarcomas when also deficient in p53. More...

Mice that develop benign cartilage lesions due to overexpression of Gli2 in chondrocytes developed lesions similar to chondrosarcomas when also deficient in p53. Gli2 overexpression and p53 deficiency had opposing effects on chondrocyte differentiation, but had additive effects negatively regulating apoptosis. Regulation of Igfbp3 expression and IGF signaling by Gli and p53 integrated their effect on apoptosis. Treatment of human chondrosarcomas or fetal mouse limbs explants with IGFBP3 or by blocking IGF increased the apoptosis rate, and mice expressing Gli2 developed substantially fewer tumors when also deficient for Igf2. IGF signaling meditated apoptosis regulates the progression to malignant chondrosarcoma. Overall design: The CH10T1/2 cell line was stably transfected with either the R150C variant PTHR1 present in enchondromas (Hopyan, S., Gokgoz, N., Poon, R., Gensure, R. C., Yu, C., Cole, W. G., Bell, R. S., Juppner, H., Andrulis, I. L., Wunder, J. S., and Alman, B. A. (2002). A mutant PTH/PTHrP type I receptor in enchondromatosis. Nat Genet 30, 306-310) or a wild type PTHR1, as previously reported (Mau, E., Whetstone, H., Yu, C., Hopyan, S., Wunder, J. S., and Alman, B. A. (2007). PTHrP regulates growth plate chondrocyte differentiation and proliferation in a Gli3 dependent manner utilizing hedgehog ligand dependent and independent mechanisms. Dev Biol 305, 28-39). Cells were grown overnight in serum free media and treated with either 10− 7 M PTHrP (Bachem, King of Prussia, Pennsylvania, USA), or carrier alone for one hour. RNA was isolated from the cells CH10T1/2 cells expressing either the R150C variant PTHR1 or wild type PTHR1. RNA was converted to double-stranded cDNA using Superscript (Gibco-Invitrogen) with a T7-(dT)24 primer, which was then transcribed to biotinylated complementary RNA (cRNA) by incorporating biotin-CTP and biotin-UTP using Enzo BioArray High Yield RNA labeling kit (Enzo Diagnostics, New York, NY). The cRNA labeling and hybridizations were then performed according to Affymetrix GeneChip Protocol (Affymetrix Inc., Santa Clara, CA). The chips were scanned for fluorescence signal detection. Affymetrix - GeneChip® Mouse Genome 430A 2.0 Array was utilized. Less...