Inactivation of p53 gene in human and murine osteosarcoma cells

Abstract

SummaryWe examined structure and expression of the p53 and Rb genes in a C3HOS transplantable mouse model of osteosarcoma. The results were compared to analogous studies conducted with five human osteosarcoma cell lines. The p53 gene was found rearranged in the mouse tumour. The rearrangement mapped to the first intron region of the p53 gene and as a result, no p53 expression could be detected in C3HOS tumours. Using p53 genomic probes, we have detected the same rearrangement in the original radiation-induced tumour and the various clones that were isolated from it. Deletion and rearrangement of the p53 gene were also found in three out of five of the human osteosarcoma cell lines . No p53 expression could be detected in these three cell lines. In the affected human osteosarcoma cell lines, the rearrangement involved the first intron region. In addition, the mouse tumour was analysed for structural and expression changes in the Rb and the c-myc genes. Normal expression of both genes were detected in the murine tumour. Only one (Saos-2) human osteosarcoma cell line exhibited gross structural alteration in the retinoblastoma gene. The results suggest that the inactivation of p53 may be an important step in the development of osteosarcomas, and that a rearrangement affecting the first intron is common in osteosarcomas.

A highly conserved proapoptotic gene, IKIP, located next to the APAF1 gene locus, is regulated by p53

“…Note that only transfected cells express the ECFP-ER marker, whereas all cells express IKIP used the human osteogenic sarcoma cell lines U-2 OS and Saos-2, which are p53-wt and -deficient, respectively. 20 As shown by Western blotting using the anti-IKIP1 antiserum, the p53-deficient Saos-2 cells expressed significantly lower amounts of (endogenous) IKIP1 (Figure 7c). No changes were detected in response to TNFa.…”

Sensitization of osteosarcoma cells to apoptosis by oncostatin M depends on STAT5 and p53

“…An increased Bnip-3 and Mcl-1 level, as well as a decreased Bak level, was also observed. Because MG63 cells have a rearrangement mutation of the p53 gene, which results in disruption of p53 protein function (Chandar et al, 1992), we then asked whether OSM could modulate the expression/activation of this transcription factor known to regulate expression of several Bcl-2 members. In OSRGA cells (Figure 3a and b) but not in MG63 cells (Supplementary Figure 2f), we observed an induced phosphorylation of p53 after 24-48 h of OSM treatment, in correlation with an accumulation of total p53.…”

“…b OSRGA, POS and UMR106: p53 status was defined by immunocytochemistry using a p53 antibody specific for the wild-type (wt) protein. For other cell lines, the p53 status was already defined in the literature (Diller et al, 1990;Casey et al, 1991;Chandar et al, 1992;Florenes et al, 1994;Wei, 2005). c STAT5 activation was studied after 15 min of OSM treatment by western blotting experiment using a P-STAT5 antibody.…”

Infectivity and expression of the early adenovirus proteins are important regulators of wild-type and ΔE1B adenovirus replication in human cells

“…Even after infection with a MOI of 1000 PFU's per cell only a part of the cells stained positive. Two osteosarcoma cell lines with wt p53 (U2OS) (Diller et al, 1990) or without p53 expression (Saos2) (Chandar et al, 1992) were analysed. A high infection e ciency was observed for the U2OS cells while the infectivity of the Saos2 cells was a bit lower.…”

“…The rhabdoid kidney tumor cell line G401 subclone G401.6TG.C6 (Weissman et al, 1987) and the cell lines MD468 (Nigro et al, 1989a), C33A (Sche ner et al, 1991), U2OS (Diller et al, 1990), Saos2 (Chandar et al, 1992), MCF7, 911 (Fallaux et al, 1996), Hep3B (Puisieux et al, 1993) and the primary cells VH10 and GM1492 were grown in Dulbecco's modi®ed Eagle's medium (DMEM) plus 10% FBS. The primary foreskin keratinocytes and HPV-transformed keratinocytes FK18B (Steenbergen et al, 1996) were grown in serum-free Keratinocyte Growth Medium (Life Technology, Breda, The Netherlands) supplemented with bovine pituitary extract (50 mg/ml), epidermal growth factor 5 ng/ml) and L-glutamine (2 mM).…”