Biomedical subjects

D Gioeli

Publications and source records attributed to D Gioeli.

6 recordsLinked to original sources

PubMed1999

Activation of mitogen-activated protein kinase associated with prostate cancer progression.

Using an antibody specific for dually phosphorylated extracellular-regulated kinases 1 and 2, we have examined 82 primary and metastatic prostate tumor specimens for the presence of activated mitogen-activated protein (MAP) kinase. Nonneoplastic prostate tissue showed little or no staining with activated MAP kinase antiserum. In prostate tumors, the level of activated MAP kinase increased with increasing Gleason score and tumor stage. In a separate analysis, tumor samples from two patients showed no activation of MAP kinase before androgen ablation therapy; however, following androgen ablation treatment, high levels of activated MAP kinase were detected in the recurrent tumors. Collectively, these data suggest an increase in the activation of the MAP kinase signal transduction pathway as prostate cancer progresses to a more advanced and androgen-independent disease.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1999

Analysis of oncogene, tumor suppressor gene, and chromosomal alterations in HeLa x osteosarcoma somatic cell hybrids.

Using a series of tumorigenic and non-tumorigenic somatic cell hybrids that resulted from the fusion of the human osteosarcoma cell line OHS50-P16T (P16T) with the HeLa cell line D98OR, we investigated the role that genetic mutations, including alterations of oncogenes, tumor suppressor genes, and chromosomes, play in P16T tumorigenicity. Analysis of a previously identified oncogene mutation, c-myc amplification, in the P16T cell line demonstrated that both the tumorigenic and non-tumorigenic hybrids contained the amplified c-myc gene. Analysis of previously identified P16T tumor suppressor gene alterations, p53 mutation, and loss of RB1 expression demonstrated that the mutated p53 gene was selectively maintained in both the non-tumorigenic and tumorigenic hybrids, whereas loss of RB1 expression was not maintained in either the non-tumorigenic or tumorigenic hybrids. Chromosomes 11, 13, 17, and 22 were analyzed for loss of heterozygosity (LOH) to characterize the status of these previously described chromosomal alterations in the tumorigenic and non-tumorigenic hybrids. Loss of HeLa D98OR chromosome 22, with maintenance of P16T chromosome 22, was observed in the tumorigenic hybrids, a result confirmed by LOH analysis, which demonstrated the specific loss of HeLa chromosome 22 genetic material in the tumorigenic segregants. Together, these results demonstrated that amplified c-myc, mutant p53, and RB1 genes seem to be important in osteosarcoma tumorigenicity and that an additional altered gene or genes on chromosome 22 may play a key role in osteosarcoma tumorigenicity.

Cell Transformation, Neoplastic↗

PubMed1997

Localization and characterization of a chromosome 11 tumor suppressor gene using organotypic raft cultures.

The development and progression of human cancer often involves the inactivation of tumor suppressor gene function. Alterations in human chromosome 11 during the development of human cutaneous squamous cell carcinoma suggest the presence of a tumor suppressor gene on this chromosome. Moreover, previous studies in our laboratory demonstrated the presence of a functional tumor suppressor gene on chromosome 11 for the human cutaneous squamous cell carcinoma cell line A388.6TG.c2. In this investigation, we have used organotypic culturing of epithelial cells as a novel in vitro assay for tumor suppression. A388.6TG.c2 and control cells form an abnormal stratified epithelium of 8-12 layers when cultivated on organotypic rafts. In contrast, the chromosome 11 microcell hybrids, HMC 100p4B and HMC 100p5A, form an epithelium of only two to three cell layers. This in vitro growth suppression of the chromosome 11 microcell hybrids in the organotypic rafts correlates well with our previous in vivo skin graft experiments. Comparison of the proliferation and apoptotic indices of cell lines grown on the organotypic rafts suggests that the tumor suppressor gene on chromosome 11 has restricted the ability of the microcell hybrids to stratify but has not significantly altered their ability to undergo cell division or programmed cell death. Furthermore, flow cytometric analysis of cells grown on organotypic raft cultures suggests that the chromosome 11 microcell hybrids are actively progressing through the cell cycle rather than arrested in a particular stage. We have used this novel application of organotypic raft cultures to further localize the chromosome 11 tumor suppressor gene. Introduction of a single der(11)t(X;11) chromosome lacking most of the long arm of chromosome 11 into A388.6TG.c2 does not affect growth on organotypic raft cultures. These data suggest the tumor suppressor gene maps to the long arm of chromosome 11 in the region of 11q13-qter.

Aged↗

PubMed1997

Identification of additional complementation groups that regulate genomic instability.

By somatic cell hybridization, amplification has been found to be a recessive genetic trait in three tumor cell lines examined. Studies with transgenic mice have shown that amplification frequency can be altered by a lack of wild-type TP53 (p53) activity. Other factors may regulate this phenotype in tumor cell lines possessing both wild-type p53 activity and amplification ability. Complementation analysis of somatic cell hybrids was performed to delineate groups of tumor cell lines that share a common defect that modulates the ability to amplify. The amplification frequencies of three normal fibroblast x tumor hybrids were suppressed 10-100-fold from parental tumor values, extending the observation that amplification is a recessive genetic characteristic in these cell lines. Analysis of tumor x tumor hybrids revealed at least two complementation groups. Defects in these groups differed from TP53 and implicate multiple variables in the regulation of gene amplification.

Antimetabolites, Antineoplastic↗

PubMed1996

Identification of Tumor Suppressor Genes by Microcell Hybridization

Somatic cell genetic studies gave the first proof that functional tumor suppressor genes exist in mammalian genomes. Initial studies showed that whole-cell hybrids between tumorigenic mouse or human cell lines and their normal counterparts became nontumorigenic upon inoculation into animals. However, identification of the operative tumor suppressor gene proved difficult due to the presence of the entire chromosomal complement of the normal cell parent. The development of the technique of microcell hybridization has provided a powerful method for overcoming this obstacle. Suppression of transformed properties of a cancer cell line upon transfer of single human chromosomes from normal cells directly maps the location of tumor suppressor activity. One can then use positional cloning techniques or differential expression strategies to isolate the functional tumor suppressor gene. We present a general strategy for the mapping of tumor suppressor genes in mammalian cells. We also outline some of the important control experiments as well as pitfalls encountered in such studies.

Journal Article↗

PubMed1991

Cytochrome P450IA mRNA expression in feral Hudson River tomcod.

We sought to determine if levels of cytochrome P450IA gene expression are environmentally induced in feral populations of Hudson River tomcod, a cancer prone fish, and whether laboratory exposure of tomcod to artificially spiked and naturally contaminated Hudson sediments can elicit a significant response. Using Northern blot analysis, we found levels of P450IA mRNA in tomcod collected from two Hudson River sites higher than those in tomcod from a river in Maine. Depuration of environmentally induced Hudson tomcod P450IA mRNA was rapid, with an initial detectable decline in P450 gene expression by 8 hr and basal levels reached by 5 days. Intraperitoneal injection of beta-napthoflavone in depurated Hudson tomcod resulted in a 15-fold induction of P450 gene expression within 26 hr. Exposure of depurated Hudson tomcod to natural sediment spiked with two PAHs resulted in a 7-fold induction of P450 gene expression. Exposure of depurated tomcod to sediment from a contaminated Hudson site also resulted in a 7- to 15-fold induction of P450IA mRNA expression. Northern blot analysis revealed a second polymorphic cytochrome P450IA mRNA band in some tomcod which was also detected by Southern blot analysis. Induction of cytochrome P450IA mRNA in Atlantic tomcod may provide a sensitive biomarker of environmentally relevant concentrations of some pollutants in the Hudson and other northeastern tidal rivers.

Animals↗