Loss of a tumor suppressor gene function is correlated with downregulation of chondrocyte‐specific collagen expression in syrian hamster embryo cells

Pe, Cizdziel; Hosoi, Junichi; Montgomery, JC; Rw, Wiseman; Jc, Barrett

doi:10.1002/mc.2940040105

Cited by 17 publications

(5 citation statements)

References 66 publications

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“…These cells are derived from Syrian hamster embryonic stem cells by mutagenesis (19) and have been characterized as chondrocyte-like as they express collagen type II and IX mRNAs (20). Transfection of these cells with the various constructs showed a pattern of secretion similar to that of COS-1 cells (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Embryonic Syrian hamster cells (DES4ϩ.2) transformed with diethylstilbestrol (19,20) were grown in minimum essential medium (Life Technologies) supplemented with 10% fetal bovine serum, 2 mM Lglutamine, penicillin (100 IU/ml), streptomycin (100 (g/ml), and minimum essential medium nonessential amino acids (1ϫ) (Life Technologies, Inc.). Cells were transfected at ϳ70% confluency with plasmid DNA (5 g/60-mm culture dish) in Pfx-5 lipid solution (Invitrogen) in serum-free medium for 4 h. The transfection medium was replaced with complete culture medium for 18 -24 h and then replaced with medium (as above) containing 0.5% fetal bovine serum for 48 h incubation.…”

Section: Methodsmentioning

confidence: 99%

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The Folded Protein Modules of the C-terminal G3 Domain of Aggrecan Can Each Facilitate the Translocation and Secretion of the Extended Chondroitin Sulfate Attachment Sequence

Day

Murdoch

Hardingham³

1999

Journal of Biological Chemistry

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Aggrecan is a multidomain proteoglycan containing both extended and folded protein modules. The C-terminal G3 domain contains a lectin-like, complement regulatory protein-like, and two alternatively spliced epidermal growth factor-like modules. It has been proposed that the lectin module alone has a necessary role in the intracellular translocation and secretion of proteins expressed containing G3. Constructs containing human aggrecan G3 together with 1155 bases of the adjacent chondroitin sulfate attachment region (CS-2) were prepared with different combinations and deletions of the protein modules and transfected into mammalian cells of monkey or hamster origin. The results showed that the products containing only the unfolded protein sequences (CS-2 with or without the C-terminal tail sequence) were translated and accumulated intracellularly but were not secreted. In contrast the constructs containing any of the folded protein modules and the extended CS-2 region were translated and secreted from the cells. The results show that the lectin module was not unique in facilitating the intracellular translocation and secretion of the G3 domain. The conservation of G3-like domains within the aggrecan family of proteoglycans may therefore result from their participation in other extracellular functions.Aggrecan is a large multidomain proteoglycan produced by chondrocytes and found as an essential component of the extracellular matrix of cartilage (1). The protein core consists of three globular and two extended domains. There is an Nterminal G1 domain that interacts specifically with hyaluronan to form multimolecular aggregates in which up to 100 aggrecan molecules bind to each hyaluronan chain (2). In contrast, the C-terminal G3 domain has no clearly established function. It consists of a C-type lectin module, a complement regulatory protein-like module and two alternatively spliced EGF 1 -like modules. Its structure is highly conserved among aggrecans in different species, and closely related structures are present in other members of this family of proteoglycans, versican, neurocan, and brevican (3). Its possible functions include both carbohydrate (4 -6) and protein ligand (7) interactions in the extracellular matrix, but it has also been proposed to have intracellular functions (8,9).The cause of nanomelia in the chicken was identified as a mutation in the aggrecan gene that produced a premature stop codon in the extended CS-2 chondroitin sulfate attachment region (10). This resulted in the synthesis of aggrecan lacking the normal C-terminal G3 structure, and although the protein was translated and present intracellularly in chondrocytes, it was not fully glycosylated or secreted (11,12). Cartilage is an essential forerunner of skeletal development in the embryo, and in the nanomelic chick the lack of aggrecan stunted cartilage development and long bone formation.These observations led to the proposal that the G3 domain was necessary intracellularly for the translocation and secretion of aggrecan. Expression of...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The Folded Protein Modules of the C-terminal G3 Domain of Aggrecan Can Each Facilitate the Translocation and Secretion of the Extended Chondroitin Sulfate Attachment Sequence

Day

Murdoch

Hardingham³

1999

Journal of Biological Chemistry

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“…The H I 9 and TM-I genes have been previously shown to be differentially expressed in supB+ versus supB-cells [18,19]. Downregulation of H I 9 and TM-I is a result of inhibition of transcription of these genes, as measured by nuclear run-on transcription assays [ 191.…”

Section: Resultsmentioning

confidence: 99%

“…Syrian hamster embryo cell lines were propagated in basal medium Eagle (GIBCO, Grand Island, NY) with 10% fetal bovine serum (Hyclone Laboratories, Logan, UT) in a humidified atmosphere with 10% C 0 2 . The tumor suppressor phenotype of the supB+ cells (DES4+ 1 cell line) and the loss of this suppressor phenotype in the supBcells (DES4-2 cell line) have been described previously [ 14,15,18,19]. Isolation and characterization of the tumorigenic BPGT cell line have also been reported [I 61.…”

Section: Cell Culture Conditions and Cell Synchronymentioning

confidence: 99%

Timing of replication of differentially transcribed genes in syrian hamster embryo fibroblasts

Sorscher

Barrett

Cordeiro‐Stone

1993

Molecular Carcinogenesis

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Syrian hamster embryo cell lines have been used as models of neoplastic progression in vitro. Changes in phenotype and biological properties have been observed in these cell lines in association with modulation of gene transcription. We explored this natural evolution of cells in culture to investigate the reported relationship between transcriptional activity and replication in early S phase. In this study we used two nontumorigenic cell lines that had either retained (supB+) or lost (supB-) the ability to suppress tumorigenicity of malignantly transformed hamster fibroblasts (BP6T). In association with the loss of suppressor gene function, supB- cells have downregulated the expression of the H19 and tropomyosin-I (TM-I) genes, which are actively transcribed in supB+ cells. Synchronous populations of supB+ and supB- cells were pulse-labeled with [3H]thymidine and bromodeoxyuridine at 1-h intervals during S phase; the replicating DNA was isolated by centrifugation in cesium chloride gradients and hybridized to 32P-labeled gene probes. No correlation was found between the timing of gene replication and the status of expression of these two genes. TM-I replicated during the first hour and H19 replicated between the second and third hours of the S phase in the expressing and nonexpressing cell lines. Immunoglobulin gene sequences, known to be late-replicating in fibroblasts, replicated at the end of the S phase. These results suggest that downregulation of transcription is not always accompanied by a concomitant change in time of gene replication from early to late S phase.

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“…Next we consider the rate equation for collagen/fibronectin degradation. It has been established experimentally that some tumor cell types have a limited ability to express fibronectin relative to benign cells [16, 54, 24, 64]. We assume that this rate is a small percent, ∈ f of the rate of production of benign cells.…”

Section: Notation and Kineticsmentioning

confidence: 99%

A Mathematical Model for the Onset of Avascular Tumor Growth in Response to the Loss of P53 Function

et al. 2006

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We present a mathematical model for the formation of an avascular tumor based on the loss by gene mutation of the tumor suppressor function of p53. The wild type p53 protein regulates apoptosis, cell expression of growth factor and matrix metalloproteinase, which are regulatory functions that many mutant p53 proteins do not possess. The focus is on a description of cell movement as the transport of cell population density rather than as the movement of individual cells. In contrast to earlier works on solid tumor growth, a model is proposed for the initiation of tumor growth. The central idea, taken from the mathematical theory of dynamical systems, is to view the loss of p53 function in a few cells as a small instability in a rest state for an appropriate system of differential equations describing cell movement. This instability is shown (numerically) to lead to a second, spatially inhomogeneous, solution that can be thought of as a solid tumor whose growth is nutrient diffusion limited. In this formulation, one is led to a system of nine partial differential equations. We show computationally that there can be tumor states that coexist with benign states and that are highly unstable in the sense that a slight increase in tumor size results in the tumor occupying the sample region while a slight decrease in tumor size results in its ultimate disappearance.

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Loss of a tumor suppressor gene function is correlated with downregulation of chondrocyte‐specific collagen expression in syrian hamster embryo cells

Cited by 17 publications

References 66 publications

The Folded Protein Modules of the C-terminal G3 Domain of Aggrecan Can Each Facilitate the Translocation and Secretion of the Extended Chondroitin Sulfate Attachment Sequence

The Folded Protein Modules of the C-terminal G3 Domain of Aggrecan Can Each Facilitate the Translocation and Secretion of the Extended Chondroitin Sulfate Attachment Sequence

Timing of replication of differentially transcribed genes in syrian hamster embryo fibroblasts

A Mathematical Model for the Onset of Avascular Tumor Growth in Response to the Loss of P53 Function

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