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D M Peehl

Publications and source records attributed to D M Peehl.

At least 91 records · Page 5Linked to original sources
PubMed1990

Frequency and pattern of karyotypic abnormalities in human prostate cancer.

The cytogenetic evaluation of 30 cultured primary prostatic cancer specimens obtained during radical prostatectomies of patients with relatively early stage disease is reported. The majority of specimens examined showed a normal male karyotype, 46,XY. Nine samples contained clonally abnormal populations including five specimens which were hyperdiploid (modal range, 65-92 chromosomes), one specimen containing double minute chromosomes, and three containing structural aberrations. Loss of the Y chromosome and a partial trisomy for chromosome 4 was observed in a sample from one patient. Another sample showed a translocation between the long arms of chromosomes 5 and 7. The only tumor obtained from a previously irradiated patient contained no normal cells, a modal chromosome number of 45, loss of chromosomes 2 and Y, and multiple structural rearrangements. The appearance of any clonal cytogenetic abnormality correlated in general with a poorly differentiated state of cancer. A survey of all available previous cytogenetic data on human prostate adenocarcinoma indicated that the loss of chromosomes 1, 2, 5, and Y, the gain of chromosomes 7, 14, 20, and 22, and rearrangements involving chromosome arms 2p, 7q, and 10q are the most common changes observed. This suggests that, although the assignment of a single chromosomal aberration as a marker for early stage prostatic cancer is unlikely, several consistent "hotspots" might be of significance in the etiology of this disease.

Chromosome Aberrations↗
PubMed1990

Analysis of somatic cell hybrids derived from normal human prostatic epithelial cells fused with HeLa cells.

Somatic cell hybrids have been instrumental in the recognition of specific chromosomes containing genes capable of suppressing the malignant phenotype. As a first step towards the identification of possible suppressor genes in prostate cells, we created hybrids by fusing normal prostate cells with malignant HeLa cells. Similar to hybrids made with other combinations of normal and malignant cells, the normal phenotype was dominant and the malignant phenotype was suppressed. The phenotype of the nontumorigenic hybrids after injection into nude mice resembled that of normal keratinocyte X HeLa hybrids, and tiny, nonprogressive keratinized nodules were produced. One hybrid clone was tumorigenic, possible due to the loss of a normal suppressor gene, and displayed glandular as well as squamous elements. Further characterization of these hybrids should permit isolation of specific suppressor genes, as well as promote recognition of elements that regulate the glandular phenotype.

Acid Phosphatase↗
PubMed1990

Down-regulation of a calmodulin-related gene during transformation of human mammary epithelial cells.

A human cDNA library obtained from cultured normal mammary epithelial cells (HMECs) was searched by subtractive hybridization for genes whose decrease in expression might be relevant to epithelial transformation. One clone identified by this procedure corresponded to a 1.4-kilobase mRNA, designated NB-1, whose expression was decreased greater than 50-fold in HMECs tumorigenically transformed in vitro after exposure to benzo[a]pyrene and Kirsten sarcoma virus. Sequence analysis of NB-1 cDNA revealed an open reading frame with a high degree of homology to calmodulin. NB-1 expression could be demonstrated by polymerase chain reaction amplification in normal breast, prostate, cervix, and epidermal tissues. The presence of NB-1 transcripts was variable in primary breast carcinoma tissues and undetectable in tumor-derived cell lines of breast, prostate, or other origins. NB-1 mRNA expression could be down-regulated in cultured HMECs by exposure to reconstituted extracellular matrix material, while exposure to transforming growth factor type beta increased its relative abundance. The protein encoded by NB-1 may have Ca2+ binding properties and perform functions similar to those of authentic calmodulin. Its possible roles in differentiation and/or suppression of tumorigenicity in epithelial tissues remain to be examined.

Base Sequence↗
PubMed1989

Transformation of human neonatal prostate epithelial cells by strontium phosphate transfection with a plasmid containing SV40 early region genes.

Neonatal human prostatic epithelial cells (NP-2s) were transfected by strontium phosphate coprecipitation with a plasmid (pRSV-T) containing the SV40 early region genes. The cells transfected with pRSV-T, but not the sham-transfected controls, formed rapidly growing, multilayered colonies within 2 weeks at a frequency of 1 x 10(-4) in a serum-free medium (P4-8F). In all, 28 colonies of transformed cells were isolated. Three of these have been cultured for a sufficient length of time to show that their growth potentials are well beyond that of the normal progenitor cells (NP-2s). There is also little or no indication of the culture "crisis" commonly seen in SV40-transformed cells in these transfected lines. All contain cytokeratins and SV40 T-antigen as revealed by immunofluorescence, have ultrastructural features of epithelial cells, and are pseudodiploid. None have produced tumors within 1 year after s.c. injection into nude mice. The transformed as well as the parental NP-2s cells require bovine pituitary extract for growth in serum-free medium and are stimulated by transforming growth factor beta 1 (TGF-beta 1) and epidermal growth factor in clonal growth assays. In contrast, a prostatic carcinoma cell line (PC-3) is inhibited by TGF-beta 1. This serum-free system and immortalized transfected clones will be useful for studying the action of putative prostatic carcinogens and tumor-promoting agents.

Cell Division↗
PubMed1989

Clonal growth of human prostatic epithelial cells is stimulated by fibroblasts.

The interaction of fibroblasts with adult human prostatic epithelial cells was studied in vitro. Stimulation of epithelial cell proliferation, measured by clonal growth assay, was demonstrated when prostatic epithelial cells were grown in coculture with fibroblasts. Epithelial growth in cocultures with fibroblasts was greater than could be obtained in isolated culture in an "optimized," serum-free medium previously described. Fibroblasts were able to compensate for the deletion of several growth factors from this "optimized" medium, including epidermal growth factor and insulin, but were notably unable to replace bovine pituitary extract. Epithelial growth stimulation identical to that achieved in coculture was produced by medium conditioned by fibroblasts. Similar results were obtained by using fibroblasts of adult human prostate origin, adult human skin, human fetal lung fibroblasts (IMR-90), and mouse 3T3 cells. No difference in response was demonstrated between prostatic epithelial cells derived from normal or malignant tissues. Fixed fibroblast monolayers and extracellular matrix prepared from fibroblast cultures failed to stimulate prostatic epithelial growth. These results suggest that a soluble growth factor is secreted by prostatic fibroblasts and other human fibroblasts of nonprostatic origin, as well as by embryonic mesenchymal cells from nonhuman species, which is capable of producing a marked proliferative response in vitro from adult human prostatic epithelium. This proliferative response could not be reproduced by the addition of a variety of known growth factors to prostatic epithelial cell cultures.

Cell Communication↗
PubMed1989

In vitro studies of human prostatic epithelial cells: attempts to identify distinguishing features of malignant cells.

Recent advances in culture techniques have enabled routine establishment and propagation of epithelial cells derived from normal and malignant tissues of the human prostate. Comparative studies of the responses of normal and cancer-derived cell populations to various growth and differentiation factors in vitro were undertaken to examine the possibility that cancer cells might respond differentially. Clonal growth assays in serum-free medium demonstrated that optimal proliferation of normal as well as cancer cell strains was generally dependent on the presence of cholera toxin, epidermal growth factor, pituitary extract, hydrocortisone, insulin, and high levels of calcium in the culture medium, and on the use of collagen-coated dishes. Only one cancer strain responded aberrantly to epidermal growth factor and hydrocortisone. Putative differentiation factors (transforming growth factor-beta and vitamin A) inhibited the growth of all normal and cancer strains. The origin of a cancer-derived cell strain that responded similarly to normal strains was verified by positive labeling with a prostate cancer-specific antibody, validating the conclusion from these studies that normal and cancer prostatic epithelial cells are not distinguishable on the basis of responses to the tested factors.

Antibodies, Neoplasm↗
PubMed1988

Clonal growth characteristics of adult human prostatic epithelial cells.

The ability of human epithelial cells derived from adult prostatic tissues to undergo clonal growth in culture was examined. In a previously described serum-free culture system, such cells exhibited a density-dependent growth requirement. It was found that raising the level of one of the constituents of the culture medium, bovine pituitary extract, to 100 micrograms/ml permitted excellent clonal growth when as few as 100 cells were inoculated/60-mm2 dish. Raising the levels of supplements other than pituitary extract (cholera toxin, epidermal growth factor, hydrocortisone, or insulin) did not produce this result. The average colony-forming efficiency of cells derived from primary or early passage cultures was approximately 25%. When single cell suspensions were prepared from tissue isolates and directly analyzed for clonal growth, colony-forming efficiencies were approximately 5%, perhaps indicating the proportion of stem cells with proliferative potential in the original isolates. The colony-forming efficiency of a cell population derived from cancer tissue was not significantly different from those of populations derived from normal tissues.

Cell Division↗
PubMed1987

Molecular biology of proto-oncogenes in genitourinary cancers.

The application of molecular biology to oncology has allowed the recognition of altered genes in cancer cells. The DNA sequences most commonly altered belong to the family of proto-oncogenes, which are homologous to the cancer-causing genes of RNA tumor viruses. In the normal cell, proto-oncogenes apparently have important functions in regulation of growth and differentiation. When altered by mutation, deletion, translocation or amplification in cancer cells, proto-oncogenes may disrupt fundamental cellular processes. Such aberrant functioning by abnormal proto-oncogenes may play crucial and even causative roles in cancer development. Altered proto-oncogenes have been identified in cancers of the human urogenital tract. Studies on the expression of proto-oncogenes in genitourinary cells will increase understanding of basic biological properties of these cells, and may yield information relevant to staging, diagnosis, risk factors, and markers of pathologic classification.

Chromosome Deletion↗
PubMed1987

Activated Ki-ras oncogene in human prostatic adenocarcinoma.

The role of cellular oncogenes in the development of human prostate cancer has not been extensively studied. A search for activated oncogenes was undertaken by testing DNA isolated from prostatic adenocarcinoma tissues for transforming activity in a 3T3 transfection assay. A transforming sequence homologous to Ki-ras was detected in one of the samples. DNA from the other cancers was negative in the transformation assay, suggesting that the activation of oncogenes, at least those detectable by the 3T3 transfection assay, is not a frequent event in prostate cancer. Amplification of genomic oncogene sequences in prostatic tissues was also examined, but amplification of Ki-ras, Ha-ras, c-myc, N-myc, c-sis, or c-fos was not detectable in any of the samples.

Adenocarcinoma↗
PubMed1986

Growth responses of normal, benign hyperplastic, and malignant human prostatic epithelial cells in vitro to cholera toxin, pituitary extract, and hydrocortisone.

Normal, benign hyperplastic (BPH), and malignant prostatic epithelial cells from adult humans can be serially passaged in medium PFMR-4 supplemented with 20% whole serum, cholera toxin, and epidermal growth factor (EGF). Improved growth of these cells has been achieved by optimizing the concentrations of the components of the basal medium. In the new modified medium, PFMR-4A, the only supplements required are 5% dialyzed serum, cholera toxin, EGF, pituitary extract, and hydrocortisone. Comparative studies of the growth responses of prostatic cells derived from normal central zone, normal peripheral zone, BPH nodules, and adenocarcinomas did not reveal any qualitative differences; all respond positively to the addition of cholera toxin, pituitary extract, and hydrocortisone to the culture medium. Cells of one cancer strain, however, were much less density-dependent for growth than were the other strains of normal, BPH, or malignant cells.

Adult↗
PubMed1986

Serum-free growth of adult human prostatic epithelial cells.

Proliferation of adult human prostatic epithelial cells in serum-free medium occurs upon the addition of cholera toxin, epidermal growth factor, pituitary extract, and hydrocortisone to basal medium PFMR-4A. Insulin and selenium enhance proliferation and permit growth at lower cell densities. Reducing the level of calcium in the medium dramatically alters morphology and also seems to increase proliferation. Mortal strains of cells derived from normal central or peripheral zone, benign hyperplasia, or cancer respond similarly to growth factors and calcium, but two populations of cancer cells which have been long-lived and may be immortal lines behave differently. GKC-CA cells require serum proteins or high levels of pituitary extract for optimal growth, and neither GKC-CA cells or cells of another cancer line, WB-CA, proliferate well in medium containing reduced levels of calcium. These observations may, however, be a reflection of attachment phenomena rather than of growth responses per se. Growth of cells in serum-free medium has allowed definitive studies of the effects of androgens, and regardless of cell type no response to androgens of prostate epithelial cells under any experimental conditions has been seen.

Adenocarcinoma↗
PubMed1985

Keratin immunoreactivity in the benign and neoplastic human prostate.

Keratin immunoreactivity in the benign and neoplastic human prostate was examined immunohistochemically using two monoclonal antibodies with differing specificities. One of these antibodies stained only the basal cells of the normal and hyperplastic prostatic epithelium, with no reactivity in tumor cells of prostatic adenocarcinoma. The other monoclonal antibody recognized a keratin protein present in all normal and hyperplastic columnar (secretory) epithelial cells, as well as in all cancer cells regardless of degree of tumor differentiation. In addition, the second antibody stained acinar and ductal epithelial cells exhibiting premalignant changes. Our findings indicate that keratin immunoreactivity differs among the epithelial cell populations of the human prostate, probably reflecting expression of different keratin proteins. The distinctive patterns of staining obtained with these two antibodies may assist in distinguishing hyperplastic from neoplastic prostatic epithelium, as well as in the recognition of basal cell hyperplasia, transitional cell metaplasia, and premalignant changes.

Antibodies, Monoclonal↗
PubMed1984

Serial propagation of adult human prostatic epithelial cells with cholera toxin.

Reproducible subculture of adult human prostatic epithelial cells from normal, benign hyperplastic and malignant tissue has been achieved. Cholera toxin is the key component in the culture system, but use of an optimal basal medium (PFMR-4) supplemented with a high level of serum in collagen-coated dishes also improves growth and serial propagation.

Cells, Cultured↗
PubMed1982

The role of differentiation in the suppression of tumorigenicity in human cell hybrids.

HeLax human keratinocyte hybrid cell populations behave like transformed cells in culture but do not form progressive tumors when inoculated into athymic nude mice. In this respect they behave like HeLa/fibroblast hybrids (Stanbridge et al., 1982). However, the small nodules that do form occasionally have the appearance of moderate to highly differentiated squamous-cell carcinomas. These observations suggest that differentiation might be the signal suppressing growth of human hybrid cells in vivo. Differentiation occurs rapidly and is not site-specific. Reconstitution of HeLa/keratinocyte hybrid cells in culture from differentiated nodules gave rise to a line of stem cells, capable of renewed proliferation and differentiation, and a line which lost the ability to differentiate and formed large, progressive tumors when reinjected. These tumors are anaplastic carcinomas that resemble tumors formed both by HeLa and tumorigenic segregant HeLa/fibroblast hybrid cells. Morphological evidence indicates that non-tumorigenic HeLa/fibroblast hybrid cells also respond to differentiation signals, whereas the tumorigenic segregants do not. Furthermore, the nontumorigenic hybrid-cells in the nude mouse take on the "phenotypic signature" of the normal parental cell irrespective of the tumorigenic parental cell. Efforts to identify factors in vitro mimicking these differentiation signals have so far failed, but such factors may be important elements in the regulation of proliferation in vivo.

Animals↗
PubMed1982

Human cell hybrids: analysis of transformation and tumorigenicity.

Intraspecific human-human cell hybrids provide a stable model system with which to investigate the genetic control of transformed and tumorigenic phenotypes. Using this system it has been shown that these phenotypes are under separate genetic control. Furthermore, the tumorigenic phenotype can be complemented by fusion of different tumorigenic cells, resulting in nontumorigenic hybrids. This system also provides information on the control of differentiated function. Molecular cytogenetic techniques should reveal the nature of the chromosomal control of neoplastic transformation.

Animals↗
PubMed1981

Characterization of human keratinocyte X HeLa somatic cell hybrids.

Intraspecific human cell hybrids were created by fusing normal epidermal keratinocytes with carcinoma (HeLa) cells. All of the hybrids were epithelial in morphology and exhibited a bright cytoskeletal pattern after indirect immunofluorescent labelling by antibody against keratin. Like the normal parental cells, the hybrid populations had organized arrays of microfilaments, and expressed low levels of surface fibronectin, predominantly in short "stitches" at cell boundaries. None of the cells expressed collagen type I, as expected of epithelial cells. Subcutaneous injection into nude mice revealed that the tumorigenic phenotype was initially suppressed in certain of the hybrids. However, cells of these lineages tested at later population doublings, and other hybrid clones tested at early population doublings, formed very small, non-progressive nodules, Histologically, these nodules resembled moderately to well-differentiated squamous-cell carcinomas. The properties in vitro and in vivo of these epithelial hybrids are compared to those of human fibroblast X HeLa hybrids.

Animals↗