An immortalized osteogenic cell line derived from mouse teratocarcinoma is able to mineralize in vivo and in vitro.

Abstract

Abstract. The hybrid plasmid pK4 containing the early genes of the simian virus SV-40, under the control of the adenovirus type 5 Ela promoter, was introduced into the multipotent embryonal carcinoma (EC) 1003. Expression of the SV-40 oncogenes was observed at the EC cell stage, and this allowed the derivation of immortalized cells corresponding to early stages of differentiation.Among the immortalized mesodermal derivatives obtained, one clone, C1, is committed to the osteogenic pathway. C1 cells have a stable phenotype, synthesize type I collagen, and express alkaline phosphatase activity. Although immortalized and expressing the SV-40 T antigen, the cells continue to be able to differentiate in vivo and in vitro. In vivo, after injection into syngeneic mice, they produce osteosarcomas. In vitro, the cells form nodules and deposit a collagenous matrix that mineralizes, going to hydroxyapatite crystal formation, in the presence of/~-glycerophosphate. This clonal cell line, which originates from an embryonal carcinoma, therefore differentiates into osteogenic cells in vivo and in vitro.This immortalized cell line will be useful in identifying specific molecular markers of the osteogenic pathway, to investigate gene regulation during osteogenesis and to study the ontogeny of osteoblasts.N~ current view of the development of bone cells is that osteocytes derive from primitive mesoblastic cell precursors through a cascade of events. These involve, in the case of intramembranous ossification, (a) proliferation of primitive mesoblasts, (b) differentiation of these cells into an osteoprogenitor cell, then into osteoblasts, and (c) maturation of osteoblasts with synthesis of a collagen matrix and mineralization (5,10,39,44). Up until now, models for following bone differentiation in vitro have been of two types: (a) osteoblast-like clones explanted from normal bone, and (b) clones derived from osteogenic osteosarcomas.(a) The former are normal explanted cells capable of progressively synthesizing a bone-like tissue in the presence of organic phosphate and ascorbic acid (1,3,8,9,28,35,46). This process and its hormonal regulation can therefore be studied in vitro. Collagen I maturation, in particular, has been extensively studied (11). However, the potential for division of such cells remains limited, and this precludes molecular studies. In addition, phenotypic changes with loss of osteoblastic properties often occurs in culture (47).(b) Clones derived from rat osteosarcomas have also been useful in investigating the effects of hormones (parathyroid hormone; prostaglandins) and vitamins (retinoids and vitamin D3) on bone development (17,25,29,30,41). The formation of a mineralized matrix has, however, been shown to require either the implantation of the tumoral cells in diffusion chambers within the animal (43), or the growth of the ceils in agar (37).In both model systems, the major problems encountered are the heterogeneity of the cell population within a clone, and the lack of specific markers allowing formal identi...

Increased bone formation and decreased osteocalcin expression induced by reduced Twist dosage in Saethre-Chotzen syndrome

“…Accordingly, Twist was found to control murine cranial tube morphogenesis, and mesodermal, muscle, and neuronal cell differentiation (14)(15)(16)(17)(18)(19). Twist is expressed in mesodermal-derived osteoblast precursors in vivo and in calvaria-derived murine osteoblast precursor cells in vitro (20)(21)(22), suggesting that Twist may serve as a regulator of osteoblast differentiation. However, the role of Twist in intramembranous ossification and the cellular and molecular abnormalities induced by Twist mutations on target genes in osteoblasts have not been identified.…”

“…When cultured in the presence of ascorbic acid that favors matrix formation and osteogenesis in vitro (20), M-Tw and Nl cells rapidly produced ALP + nodule-like structures. However, M-Tw cells produced more and larger nodules than Nl cells during the same period of time (8 days) (Figure 5a).…”

Genomic Insertion of the SV-40 Large T Oncogene in Normal Adult Human Trabecular Osteoblastic Cells Induces Cell Growth Without Loss of the Differentiated Phenotype

“…To overcome these limitations, several cell lines derived from normal bones of rodents [4][5][6][7][8][9][10] and humans [11][12][13][14] have been developed. As far as we know, only the HOBIT [12] and more recently, the HOB-02-C1 [14] cell lines have been established from normal adult human bone, using SV-40 large T antigen (LTAg).…”

Overexpression of murine small heat shock protein HSP25 interferes with chondrocyte differentiation and decreases cell adhesion

“…We used another system : the C1 cell line. This teratocarcinoma-derived cell line 31,32 can, in vitro, be specifically differentiated into chondrocytes, osteocytes or adipocytes according to the inducer used. 33 We have stably transfected C1 undifferentiated cells with an expression vector containing the complete HSP25 cDNA, selected two HSP25 overexpressing clones and studied the cartilage differentiation capacities of these clones.…”