Oncogenic Cell Transformation in Vitro

Abstract Data from epidemiological studies suggest that consumption of red and processed meat is a factor contributing to colorectal carcinogenesis. Red meat contains high amounts of heme, which in turn can be converted to its nitrosylated form, NO-heme, when adding nitrite-containing curing salt to meat. NO-heme might contribute to colorectal cancer formation by causing gene mutations and could thereby be responsible for the association of (processed) red meat consumption with intestinal cancer. Up to now, neither in vitro nor in vivo studies characterizing the mutagenic and cell transforming potential of NO-heme have been published due to the fact that the pure compound is not readily available. Therefore, in the present study, an already existing synthesis protocol was modified to yield, for the first time, purified NO-heme. Thereafter, newly synthesized NO-heme was chemically characterized and used in various in vitro approaches at dietary concentrations to determine whether it can lead to DNA damage and malignant cell transformation. While NO-heme led to a significant dose-dependent increase in the number of DNA strand breaks in the comet assay and was mutagenic in the HPRT assay, this compound tested negative in the Ames test and failed to induce malignant cell transformation in the BALB/c 3T3 cell transformation assay. Interestingly, the non-nitrosylated heme control showed similar effects, but was additionally able to induce malignant transformation in BALB/c 3T3 murine fibroblasts. Taken together, these results suggest that it is the heme molecule rather than the NO moiety which is involved in driving red meat-associated carcinogenesis.

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Chondroitin Sulphate Proteoglycan 4 (NG2/CSPG4) Localization in Low- and High-Grade Gliomas

Cells ◽

10.3390/cells9061538 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1538 ◽

Cited By ~ 1

Author(s):

Marta Mellai ◽

Laura Annovazzi ◽

Ilaria Bisogno ◽

Cristiano Corona ◽

Paola Crociara ◽

...

Keyword(s):

Cell Transformation ◽

Chondroitin Sulphate ◽

Molecular Genetic ◽

Malignant Gliomas ◽

Malignant Cell ◽

Wild Type ◽

Sulphate Proteoglycan ◽

Chondroitin Sulphate Proteoglycan ◽

Proteoglycan 4

Background: Neuron glial antigen 2 or chondroitin sulphate proteoglycan 4 (NG2/CSPG4) is expressed by immature precursors/progenitor cells and is possibly involved in malignant cell transformation. The aim of this study was to investigate its role on the progression and survival of sixty-one adult gliomas and nine glioblastoma (GB)-derived cell lines. Methods: NG2/CSPG4 protein expression was assessed by immunohistochemistry and immunofluorescence. Genetic and epigenetic alterations were detected by molecular genetic techniques. Results: NG2/CSPG4 was frequently expressed in IDH-mutant/1p19q-codel oligodendrogliomas (59.1%) and IDH-wild type GBs (40%) and rarely expressed in IDH-mutant or IDH-wild type astrocytomas (14.3%). Besides tumor cells, NG2/CSPG4 immunoreactivity was found in the cytoplasm and/or cell membranes of reactive astrocytes and vascular pericytes/endothelial cells. In GB-derived neurospheres, it was variably detected according to the number of passages of the in vitro culture. In GB-derived adherent cells, a diffuse positivity was found in most cells. NG2/CSPG4 expression was significantly associated with EGFR gene amplification (p = 0.0005) and poor prognosis (p = 0.016) in astrocytic tumors. Conclusion: The immunoreactivity of NG2/CSPG4 provides information on the timing of the neoplastic transformation and could have prognostic and therapeutic relevance as a promising tumor-associated antigen for antibody-based immunotherapy in patients with malignant gliomas.

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Direct repeats bind the EcR/USP receptor and mediate ecdysteroid responses in Drosophila melanogaster.

Molecular and Cellular Biology ◽

10.1128/mcb.16.6.2977 ◽

1996 ◽

Vol 16 (6) ◽

pp. 2977-2986 ◽

Cited By ~ 70

Author(s):

C Antoniewski ◽

B Mugat ◽

F Delbac ◽

J A Lepesant

Keyword(s):

Fat Body ◽

Cell Transformation ◽

Direct Repeat ◽

Transgenic Animals ◽

Transcriptional Level ◽

Regulatory Sequences ◽

Direct Repeats ◽

Fbp1 Gene

The steroid hormone 20-hydroxyecdysone plays a key role in the induction and modulation of morphogenetic events throughout Drosophila development. Previous studies have shown that a heterodimeric nuclear receptor composed of the EcR and USP proteins mediates the action of the hormone at the transcriptional through binding to palindromic ecdysteroid mediates the action of the hormone at the transcriptional level through binding to palindromic ecdysteroid response elements (EcREs) such as those present in the promoter of the hsp27 gene or the fat body-specific enhancer of the Fbp1 gene. We show that in addition to palindromic EcREs, the EcR/USP heterodimer can bind in vitro with various affinities to direct repetitions of the motif AGGTCA separated by 1 to 5 nucleotides (DR1 to DR5), which are known to be target sites for vertebrate nuclear receptors. At variance with the receptors, EcR/USP was also found to bind to a DR0 direct repeat with no intervening nucleotide. In cell transformation assays, direct repeats DR0 to DR5 alone can render the minimum viral tk or Drosophila Fbp1 promoter responsive to 20-hydroxyecdysone, as does the palindromic hsp27 EcRE. In a transgenic assay, however, neither the palindromic hsp27 element nor direct repeat DR3 alone can make the Fbp1 minimal promoter responsive to premetamorphic ecdysteroid peaks. In contrast, DR0 and DR3 elements, when substituted for the natural palindromic EcRE in the context of the Fbp1 enhancer, can drive a strong fat body-specific ecdysteroid response in transgenic animals. These results demonstrate that directly repeated EcR/USP binding sites are as effective as palindromic EcREs in vivo. They also provide evidence that additional flanking regulatory sequences are crucially required to potentiate the hormonal response mediated by both types of elements and specify its spatial and temporal pattern.

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The use of the S. typhimurium mutation assay and cell transformation in vitro as short-term carcinogen tests to monitor the structural inactivation of known carcinogens and to detect potential carcinogenicity in new compounds

Mutation Research/Environmental Mutagenesis and Related Subjects ◽

10.1016/0165-1161(77)90045-0 ◽

1977 ◽

Vol 46 (3) ◽

pp. 204-205

Author(s):

John Ashby ◽

D. Paton ◽

J.A. Styles ◽

Diana Anderson ◽

E. Longstaff

Keyword(s):

Cell Transformation ◽

Short Term ◽

Mutation Assay ◽

New Compounds

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Time- and Dose-Dependent Effects of 17 Beta-Estradiol on Short-Term, Real-Time Proliferation and Gene Expression in Porcine Granulosa Cells

BioMed Research International ◽

10.1155/2017/9738640 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 12

Author(s):

Sylwia Ciesiółka ◽

Joanna Budna ◽

Karol Jopek ◽

Artur Bryja ◽

Wiesława Kranc ◽

...

Keyword(s):

Real Time ◽

Granulosa Cells ◽

Hormone Receptor ◽

Proliferative Activity ◽

Cell Transformation ◽

Luteinizing Hormone Receptor ◽

Luteal Cell ◽

Ovarian Activity ◽

Short Term

The key mechanisms responsible for achievement of full reproductive and developmental capability in mammals are the differentiation and transformation of granulosa cells (GCs) during folliculogenesis, oogenesis, and oocyte maturation. Although the role of 17 beta-estradiol (E2) in ovarian activity is widely known, its effect on proliferative capacity, gap junction connection (GJC) formation, and GCs-luteal cells transformation requires further research. Therefore, the goal of this study was to assess the real-time proliferative activity of porcine GCs in vitro in relation to connexin (Cx), luteinizing hormone receptor (LHR), follicle stimulating hormone receptor (FSHR), and aromatase (CYP19A1) expression during short-term (168 h) primary culture. The cultured GCs were exposed to acute (at 96 h of culture) and/or prolonged (between 0 and 168 h of culture) administration of 1.8 and 3.6 μM E2. The relative abundance of Cx36, Cx37, Cx40, Cx43, LHR, FSHR, and CYP19A1 mRNA was measured. We conclude that the proliferation capability of GCs in vitro is substantially associated with expression of Cxs, LHR, FSHR, and CYP19A1. Furthermore, the GC-luteal cell transformation in vitro may be significantly accompanied by the proliferative activity of GCs in pigs.

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Cell transformation by avian defective leukaemia viruses

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1980.0142 ◽

1980 ◽

Vol 210 (1180) ◽

pp. 397-409 ◽

Cited By ~ 2

Keyword(s):

Bone Marrow ◽

Bone Marrow Cells ◽

Cell Transformation ◽

Nucleic Acid Hybridization ◽

Phenotypic Analysis ◽

Amino Terminal ◽

Cell Specificity ◽

Core Proteins ◽

Carboxy Terminal

A comparative study of seven independently isolated defective leukaemia viruses has been carried out. Phenotypic analysis of the chicken bone marrow cells transformed in vitro allowed the separation of these seven viruses into three groups based on the differentiation phenotype of the transformed cell. Nucleic acid hybridization studies revealed that these seven viruses had acquired cellular sequences. Interestingly, these studies also showed that the viruses within the same biological grouping had acquired related sequences. This indicates that viruses that have acquired the same or similar cellular sequences have very similar oncogenic capabilities. Analysis of proteins expressed in cells transformed by these viruses demonstrated that the cellular sequences were usually inserted within the gene for the viral core proteins, gag . Therefore the cellular sequences are expressed as a gag -related fusion protein which has an amino-terminal region derived from the gag gene and a carboxy-terminal half derived from the cellular sequences. Two exceptions to this are discussed. The general conclusion from these studies is that defective leukaemia viruses transform cells by virtue of acquired host cellular sequences. The ability of these viruses to transform cells and the target cell specificity of the transformation depends on these cellular sequences.

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