Biomedical subjects

J E Price

Publications and source records attributed to J E Price.

At least 37 records · Page 2Linked to original sources

PubMed1996

Inhibition of colony formation in agarose of metastatic human breast carcinoma and melanoma cells by synthetic glycoamine analogs.

We studied the influence of 10 synthetic glycoamine analogs on colony formation in 0.3 and 0.9% agarose by metastatic human breast carcinoma (MDA-MB-435) and melanoma (TXM-13) cells. Nine synthetic analogs significantly inhibited the colony formation in 0.9% agarose of MDA-MB-435 human breast carcinoma cells; five compounds caused a 73-83% reduction of colony formation. Seven synthetic glycoamines caused a significant inhibition of colony formation in 0.9% agarose by TXM-13 melanoma cells with the inhibitory effect ranging from 71 to 87%. The 50% inhibition (I50) doses and relative activity rank of the compounds were similar for both breast carcinoma and melanoma cell lines. The murine B16 melanoma cell aggregation assay was employed to elucidate the potential mechanism(s) of the inhibitory activity of synthetic glycoamines. The relative activity ranks of the compounds based on the independently determined I50 doses for both cell aggregation and clonogenic growth assays were very similar for the four most active synthetic analogs and clearly indicated the importance of hydrophobic amino acid in mediating the bioactivity of synthetic glycoamines. In both experimental systems (clonogenic growth in agarose and cell aggregation assay) the leading compound was N-(1-deoxy-D-fructos-1-yl)-D-leucine (Fru-D-Leu) and the least active analog was N-(l-deoxy-D-fructos-1-yl)-glycine (Fru-Gly). These results show that synthetic glycoamines may act by competing for specific carbohydrate-lectin interactions, particularly those involving beta-galactoside-specific lectins expressed on metastatic cells.

Amino Sugars↗

PubMed1996

Predominance of the metastatic phenotype in hybrids formed by fusion of mouse and human melanoma clones.

The fusion of mouse and human melanoma cells that were tumorigenic but had different metastatic capabilities resulted in hybrids that were metastatic when injected intravenously or subcutaneously into nude mice, regardless of whether it was the mouse or the human melanoma clone that was metastatic. The H7 hybrid line, formed by fusing murine nonmetastatic K1735 C19 cells with human metastatic A375 C15 cells retained high metastatic potential over more than 50 sub-culture passages, suggesting that the dominant metastatic phenotype in these hybrid cells was stable. Using fluorescent in situ hybridization (FISH), human chromosome 17 was consistently identified as the predominant human chromosome in the majority of H7 cells tested between passages 20 and 60. Western blot analysis showed that the hybrid cells expressed human nm23 protein, indicating that at least one gene on the human chromosome 17 was functional. Immunocytochemistry and immunoprecipitation showed that the metastatic A375 C15 and H7 cells expressed p53 protein, but that the nonmetastatic K1735 C19 melanoma cells did not. Sequencing the human p53 gene in A375 C15N and H7 showed mutations in exon 7. Using a bioassay technique, we showed that K1735 C19 cells can spread from subcutaneous tumors to the lungs of nude mice yet fail to form metastases. With the addition of human chromosome 17 from A375 C15 cells, which carries a mutant p53 gene, the cells readily formed lung metastases. In this melanoma hybrid, a mutant p53 gene appears to confer a survival advantage on cells arrested in the lungs of nude mice and thus contributes to the growth of metastatic cells.

Animals↗

PubMed1996

Metastasis from human breast cancer cell lines.

Immunodeficient animals, principally nude mice, when used in appropriately designed studies have been shown to be useful for the experimental analysis of human breast cancer metastasis. As with many other human tumors, the implantation of breast cancer cells into an anatomically appropriate tissue (the mammary fatpad) results in increased tumor take and incidence of metastasis for certain cell lines compared with subcutaneous injection. Testing a number of widely available human breast cancer cell lines identified the MDA-MB-435 cell line as the most metastatic, producing lung and lymph node metastases in a high proportion of nude and severe combined immunodeficient (SCID) mice after injection in the mammary fatpad. Mixing human breast cancer cells with normal fibroblasts or with Matrigel also increases the tumor incidence and growth rates in nude mice. Different routes of injection can be used to assess the ability of human breast cancer cells to form metastatic lesions in the lungs (i.v. injection), the liver (injection in the spleen), the brain (direct or intracarotid artery injection) and the bone marrow and bone (injection into the left ventricle of the heart). These different approaches demonstrate the potential of experimental studies of human breast cancer growth and metastasis using immunodeficient mice; this model is valuable for experiments that test the role of metastasis-associated genes and the efficacy of novel forms of therapy.

Animals↗

PubMed1996

Selective growth of human melanoma cells in the brain parenchyma of nude mice.

The purpose of this study was to determine whether the growth of human melanoma cells in the brain parenchyma is selective and represents the growth of unique cells. Six human melanoma cell lines derived from cutaneous lymph node or brain metastases (from six different patients) and melanoma cells isolated from fresh surgical specimens of two primary cutaneous melanomas, two lymph node metastases and two brain metastases (each from a different patient) were injected into the subarachnoid space of nude mice. All melanomas produced growths in the leptomeninges, but only melanoma cells isolated from brain metastases infiltrated into and grew in the brain parenchyma of nude mice. The results from in vitro assays for cell motility or production of gelatinase activity did not correlate with in vivo growth pattern. However, the in vitro growth of human melanoma cells in the presence of TGF-beta 2 inversely correlated with potential for brain parenchyma metastasis, i.e. the growth of cells from brain metastases was least inhibited by TGF-beta 2. These data suggest that melanoma brain parenchyma metastases are produced by unique cells that may be resistant to the antiproliferative effects of TGF-beta 2.

Animals↗

PubMed1994

Analyzing the metastatic phenotype.

The dissemination of cells from a primary tumor, resulting in the progressive growth of metastatic carcinoma in distant sites, is the most common cause of death of cancer patients. The observations from clinical studies and the results of experimental studies using rodent tumors and human cancer cells implanted into immunodeficient host animals suggest that metastasis is not a random event, but rather the result of a sequence of selective events, many of which involve interactions with elements of the microenvironment of the primary and metastatic tumors. Analysis of the metastatic potential of a human tumor cell population has been greatly improved by the introduction of orthotopic models of tumor growth and metastasis, which have demonstrated that implanting human tumor cells into the appropriate tissue in an immunodeficient rodent can increase both tumor take and incidence of metastasis. These will be the models that should be used to validate the identity of candidate metastasis-associated genes, and to determine the value of new forms of therapy, either genetic or pharmacological, for controlling metastatic cancer growth.

Animals↗

PubMed1994

Imaging, biodistribution and therapy potential of halogenated tamoxifen analogues.

Tamoxifen binds to estrogen receptors (ERs) and prevents breast cancer cell proliferation. This study is aimed at developing a ligand for imaging ER (+) breast tumors by positron emission tomography (PET) or single photon emission computed tomography (SPECT). [18F]-Labeled tamoxifen analogue ([18F]FTX) was prepared in 30-40% yield and [131I]-labeled tamoxifen analogue ([131I]ITX) was prepared in 20-25% yield. In mammary tumor-bearing rats, the biodistribution of [18F]FTX at 2 h showed a tumor uptake value (% injected dose/gram tissue) of 0.41 +/- 0.07; when rats were pretreated with diethylstilbestrol (DES), the value changed to 0.24 +/- 0.017. [131I]ITX at 6 h showed a tumor uptake value of 0.26 +/- 0.166; when rats were pretreated with DES, the value changed to 0.22 +/- 0.044. Priming tumor-bearing rats with estradiol, a tumor uptake value for [131I]ITX was increased to 0.48 +/- 0.107 at 6 h. In the [3H]estradiol receptor assay, tumors had a mean estrogen receptor density of 7.5 fmol/mg of protein. In gamma scintigraphic imaging studies with [131I]ITX, the rabbit uterus uptake can be blocked by pretreatment with DES. Both iodo-tamoxifen and tamoxifen reduced ER(+) breast tumor growth at the dose of 50 micrograms in tumor-bearing mice. The findings indicate that tamoxifen analogue uptake in tumors occurs via an ER-mediated process. Both analogues should have potential for diagnosing functioning ER(+) breast cancer.

Animals↗

PubMed1994

Terminal differentiation and apoptosis in experimental lung metastases of human osteogenic sarcoma cells by wild type p53.

Human SAOS-2 osteogenic sarcoma cells are not metastatic in nude mice and do not express p53. We have selected a variant line (SAOS-LM2) that is tumorigenic and metastatic in nude mice. These cells were transfected with the p53 wild-type (p53wt) or mutated (p53mut 143A) gene, whose expression was verified by reverse transcriptase PCR, cDNA sequencing, and protein immunoprecipitation. Cells were injected i.v. into nude mice, and 4 months later, the mice were necropsied. All cell lines produced a similar number of visible lung metastases, albeit of different sizes. Microscopic examination revealed that most lung metastases in mice injected with p53wt cells (but not p53mut 143A or control cells) consisted of osteoid matrix and apoptotic cells. Expression of either p53wt or p53mut 143A verified the origin of the metastases. These data suggest that transfection of SAOS-LM2 cells with p53wt is associated with in vivo induction of terminal differentiation and apoptosis that inhibit progressive growth of metastases.

Animals↗

PubMed1993

Enhanced c-erbB-2/neu expression in human ovarian cancer cells correlates with more severe malignancy that can be suppressed by E1A.

Amplification or overexpression of c-erbB-2/neu protooncogene, or both, occur frequently in many different types of human cancers and have been shown to correlate with decreased survival in ovarian cancer patients. We have previously found that the ovarian carcinoma cell line SK-OV-3 overexpresses c-erbB-2/neu mRNA. To further study the biological effect of c-erbB-2/neu overexpression in SK-OV-3 cells, we injected such cells i.p. into female nu/nu mice and found that this cell line forms extensive abdominal tumors and ascites. From the ascites in an injected mouse, we established the SKOV3.ip1 cell line and found that it expressed 2-fold more c-erbB-2/neu-encoded p185 proteins than the parental SK-OV-3 cells. When transformation phenotypes of SK-OV-3 and SKOV3.ip1 cells were compared, SKOV3.ip1 cells showed higher cell growth and DNA synthesis rates, formed more colonies in soft agar, produced larger s.c. tumors, and resulted in shorter survival of nu/nu mice after i.p. injection. These data indicate that the level of c-erbB-2/neu overexpression may correlate with the degree of malignancy in these ovarian carcinoma cells. Since we had previously shown that the adenovirus 5 E1A gene product can suppress transformation and metastatic properties induced by mutation-activated rat neu oncogene in mouse embryo fibroblast cells, we further examined whether E1A can abrogate malignancy in c-erbB-2/neu-overexpressing human ovarian cancer cells. We introduced the E1A gene into c-erbB-2/neu-overexpressing SKOV3.ip1 cells and found that the E1A-expressing ovarian cancer cell lines had decreased c-erbB-2/neu-encoded p185 expression and reduced malignancy, including a decreased ability to induce tumors in nu/nu mice. Therefore, we concluded that E1A is a tumor suppressor gene for c-erbB-2/neu-overexpressing human ovarian cancer cells and may be useful in developing therapeutic reagents for these human cancers.

Adenovirus E1A Proteins↗

PubMed1992

Basement membrane collagen-IV synthesis in colorectal tumours.

Many studies suggest that increased proteolysis accounts for the epithelial basement membrane (EBM) breaks commonly seen in carcinomas. As failure to produce or maintain EBM may also be important, we chose to investigate synthesis of basement membrane collagen-IV in human colorectal carcinomas. First, to determine the cellular origin of EBM collagen-IV, species-specific antibodies were used to analyse caecal xenografts of 4 different human colorectal-carcinoma-derived cell lines. The results of this study suggest an exclusively stromal cell origin for EBM collagen-IV. Next, the distribution of periglandular myofibroblasts in carcinomas was examined, since in normal mucosa their location and ultrastructural features suggest that they play a role in EBM maintenance. They were generally abundant in normal mucosa and adenomas, but sparsely distributed in carcinomas, particularly at the invasive periphery where EBM collagen-IV immunostaining is most deficient. Finally, the in situ hybridization technique was used to define cell populations synthesizing collagen-IV. In normal mucosa, no collagen-IV mRNA was detected in any component, while in carcinomas, the mRNA was clearly detectable in vascular endothelial cells but not in any other cell type. Increased vascular collagen-IV production in carcinomas may be at least partly due to tumour-induced angiogenesis, since new blood-vessel formation requires the synthesis of new vascular basement membranes.

Adenoma↗

PubMed1992

Gastroesophageal pH step-up inaccurately locates proximal border of lower esophageal sphincter.

Limiting the widespread use of 24-hr pH monitoring is the necessity of manometrically placing the pH probe 5 cm above the proximal lower esophageal sphincter (LES) border. Therefore, we prospectively compared LES localization by gastroesophageal pH step-up with manometry in 71 patients and 14 asymptomatic volunteers. The gastroesophageal pH step-up significantly correlated with the proximal LES border in patients (r = 0.53, P less than 0.0001) and volunteers (r = 0.91, P less than 0.0001). Based on previously published criteria, the pH step-up value was considered acceptably accurate if it was within +/- 3 cm (6 cm total span) of the manometrically determined proximal LES border. In 58% of patients and 29% of volunteers the pH step-up occurred outside this accuracy range. Esophagitis (P = 0.015) and abnormal reflux parameters (P = 0.002) were variables contributing to this error. Subsequent analysis found that the pH step-up overestimated the proximal LES border and occurred at the midportion of the sphincter. The pH step-up still inaccurately located the mid LES in 34% of patients. Therefore, manometry should remain the standard for accurate LES localization prior to placing the pH probe.

Adolescent↗

PubMed1992

Differential permeability of the blood-brain barrier in experimental brain metastases produced by human neoplasms implanted into nude mice.

This study clarified whether and when the blood-brain barrier in experimental brain metastases is impaired by using hydrosoluble sodium fluorescein (MW 376) as a blood-brain barrier function indicator. Cells from eight human tumor lines (four melanomas, two breast carcinomas, one colon carcinoma, and one renal carcinoma) were inoculated into the internal carotid artery of nude mice. Brain metastases at different stages of development were sampled and the permeability of the blood-brain barrier around the metastases determined. Histologic examination showed two patterns of tumor growth. In the first, tumor cells formed isolated, well-defined nodules in the parenchyma of the brain. In lesions smaller than 0.2 mm2, the blood-brain barrier was intact. In the second, small diffuse nests of tumor cells were distributed throughout the brain parenchyma. The blood-brain barrier was intact until the small tumor cell colonies coalesced to form large tumor masses. These results suggest that the permeability of the blood-brain barrier varies among different experimental brain metastases and that its function is related to the growth pattern and size of the lesions.

Animals↗

PubMed1992

The LES locator: accurate placement of an electrode for 24-hour pH measurement with a combined solid state pressure transducer.

Twenty-four-hour esophageal pH monitoring is the gold standard for diagnosing gastroesophageal reflux disease. A possible limitation to the widespread use of this test is that manometry is required for accurate placement of the pH electrode 5 cm above the lower esophageal sphincter. We compared the accuracy of a single solid state pressure transducer, combined with a pH electrode, in determining the proximal border of the lower esophageal sphincter (LES) with the values obtained from stationary manometry in 40 patients referred to our laboratory for 24-h pH studies. Not only was there a strong correlation (r = 0.9) between LES values obtained by the two techniques, but none of the values obtained by the single solid state transducer were outside the clinically accepted range of greater than +/- 3 cm. The presence of a hiatal hernia or low sphincter pressure did not affect these measurements. The larger probe was tolerated somewhat less well (p = 0.02) than a standard antimony electrode during the prolonged pH studies. In conclusion, a single solid state pressure transducer on a pH probe with the help of a LES locator accurately identifies the proximal border of the LES. Therefore, stationary esophageal manometry is no longer needed prior to 24-h pH monitoring, potentially making this important clinical tool available to a wider variety of clinicians at all levels of the health care system, in investigating gastroesophageal reflux and its protean clinical presentations.

Adult↗

PubMed1991

Malignant potential of cells isolated from lymph node or brain metastases of melanoma patients and implications for prognosis.

We studied the correlation between the formation of brain metastasis and the malignant growth potential of seven human melanoma cell lines, isolated from lymph node metastases (A375-SM, TXM-1, DM-4) or from brain metastases (TXM-13, TXM-18, TXM-34, TXM-40), and the potential of three variants of the mouse K-1735 melanoma. Growth rates in different concentrations of fetal bovine serum and colony-forming efficiency in semisolid agarose were measured, and the tumorigenicity and metastatic ability were determined in nude mice (for the human melanoma cell lines) or in C3H/HeN mice (for the K-1735 variants). The ability to form brain metastasis was tested by injection of cells into the carotid artery. A high colony-forming efficiency in agarose, especially at concentrations of agarose greater than 0.6%, corresponded with high tumor take rates, rapid tumor growth rates, and metastatic colonization of the lungs of the recipient mice. For the human melanomas, the lymph node metastasis-derived cells were more tumorigenic and metastatic than the brain metastasis-derived cells. In the K-1735 mouse melanoma, the tumorigenic and metastatic behavior of the cells after i.v. and s.c. injection corresponded with growth in agarose cultures. However, for growth in the brain after intracarotid injection, the different melanoma cell lines showed similar frequencies of tumor take, regardless of tumorigenicity in other sites of the recipient mice, although mice given injections of brain metastasis-derived cells survived longer than mice given injections of lymph node metastasis (human melanoma) or lung metastasis (K-1735 M-2)-derived cell lines. The results from the human and mouse melanoma cell lines show that the brain metastasis-derived cell lines were not more malignant than the lymph node or lung metastasis-derived cells. These data imply that the production of brain metastasis is not always the final stage of a metastatic cascade.

Animals↗

PubMed1991

Growth modulation by epidermal growth factor (EGF) in human colonic carcinoma cells: constitutive expression of the human EGF gene.

The functional role of epidermal growth factor (EGF) in epithelium-derived human colonic carcinoma cells was investigated by transfection with plasmid pUCDS3, which contained synthetic human EGF encoding sequences, into two human colonic carcinoma cell types with dissimilar phenotypic properties: the moderately differentiated and growth factor-responsive Moser and the highly metastatic KM12SM cells. The Moser cells exhibited a proliferative response to treatment with exogenous EGF, while the KM12SM cells did not. The constitutive expression of the human EGF gene in these colonic carcinoma cell types resulted in elevated expression of EGF mRNA, with concurrent production and secretion of a large amount of EGF, and downmodulation of transforming growth factor-alpha (TGF-alpha) secretion. Growth stimulation and down-modulation of both high and low affinity EGF receptors were observed in the EGF-transfected Moser clones. Results of experiments using anti-EGF and anti-EGF-receptor antibody to block the proliferation of EGF-transfected Moser clones suggested that autocrine stimulatory mechanisms involving both EGF and TGF-alpha were operative in these cells. By comparison, a growth-inhibitory effect, with no apparent EGF receptor modulation, was observed in the EGF-transfected KM12SM clones. Both the parental and EGF-transfected KM12SM clones possessed fewer EGF receptors than the Moser cells, and anti-EGF or anti-EGF-receptor antibody did not affect the cells' growth properties. These results suggested that the mechanisms of growth inhibition in the EGF-transfected KM12SM clones were non-autocrine or intracellular in nature. Thus, constitutive expression of the human EGF gene in two phenotypically different, epithelium-derived human colonic carcinoma cells resulted in divergent altered growth characteristics.

Cell Division↗

PubMed1991

In vitro platelet aggregability studies: lack of evidence for platelet hyperactivity in systemic sclerosis.

Systemic sclerosis is characterised by vascular endothelial damage. Platelets adhering to the exposed subendothelium may contribute to the inflammatory changes found in the vessel wall. Increased in vitro platelet aggregability in systemic sclerosis has been reported. In vitro platelet aggregation of platelet rich plasma obtained from patients with systemic sclerosis (CREST (calcinosis, Raynaud's phenomenon oesophageal dysmotility, sclerodactyly, telangiectasia) variant) and from controls matched for age and sex was compared. Collagen, ADP, and platelet activating factor were used as aggregating agents. The actions of a platelet activating factor antagonist, BN52063, were also examined. Each agonist caused dose dependent platelet aggregation; there was no difference in either rate of primary aggregation or maximum percentage aggregation between platelets derived from patients with systemic sclerosis and from the control group (analysis of variance). BN52063 was shown to be a dose dependent, competitive antagonist of platelet aggregation induced by platelet activating factor; there was no difference in its action on platelets derived from patients with systemic sclerosis or controls. These results do not support the hypothesis that platelets from patients with systemic sclerosis are hyperactive and may explain the disappointing results obtained with antiplatelet drugs in systemic sclerosis.

Adenosine Diphosphate↗

PubMed1991

Relative malignant potential of human breast carcinoma cell lines established from pleural effusions and a brain metastasis.

Three human breast cancer cell lines from pleural effusions (MDA-MB-435, MDA-MB-231, MDA-MB-468) and one from a brain metastasis (MDA-MB-361) were tested for growth potential in vitro (minimum serum requirements, growth in semisolid agarose), for tumorigenicity and metastasis in nude mice following injection into the mammary fatpad (m.f.p.) and intravenously (i.v.), and for formation of experimental brain metastasis following injection into the carotid artery (i.a.). Colony-forming efficiency of the breast cancer cells in dense agarose corresponded with metastatic potential of the m.f.p. tumors. The results consistently ranked the 4 cell lines as follows: MDA-MB-435 greater than MDA-MB-231 greater than MDA-MB-468 greater than MDA-MB-361, from the most to the least aggressive. The exception was for tumor growth in the brain after i.a. injection of cells, where MDA-MB-361 cells were ranked as second highest for tumor take, but with the slowest growth rate. These results indicate that in this series of breast carcinomas, the cells from a brain metastasis (MDA-MB-361) have a lower malignant potential than cells from visceral metastases.

Animals↗

PubMed1990

The biology of metastatic breast cancer.

Early detection and surgical removal of breast cancer are most effective in managing a disease that may affect up to one in ten women in North America and Western Europe. However, one of the most important prognostic indicators for breast cancer is the presence of neoplastic cells in the axillary lymph nodes. The dissemination of cells from a primary lesion, resulting in the progressive growth of metastatic carcinoma in distant sites (including bone, lungs, liver, and brain) is the most common cause of death in breast cancer patients. Experimental studies on the biology of metastatic breast cancer have used rodent tumor systems, and, in recent years, the transplantation of human breast carcinoma cells into athymic mice. The results of such studies, combined with clinical observations, suggest that metastasis is not a random event. The formation of secondary lesions is the result of a sequence of selective events. A better understanding of the metastatic phenotype from cellular and molecular analyses will provide a basis for rational approaches to preventing and treating this most lethal aspect of breast cancer.

Animals↗

PubMed1990

Immune response to progressor variants derived from transfection of an ultraviolet radiation-induced C3H mouse regressor tumor cell line with activated Harvey-ras oncogene.

Skin cancers induced in mice by UV radiation often exhibit a regressor phenotype. In order to determine how tumors escape the immune defenses of the normal immunocompetent host, we sought to isolate progressor variants from a UV radiation-induced C3H mouse regressor fibrosarcoma cell line, UV-2240, by transfection with an activated Ha-ras oncogene. A cotransfection protocol using pSV2-neo DNA, which confers resistance to the antibiotic G418, was used to select transfected cells. Injection of Ha-ras-transfected UV-2240 cells s.c. into immunocompetent C3H mice produced tumors in four of 36 animals. In contrast, UV-2240 cells transfected with pSV2-neo DNA alone or mock transfected with CaPO4 did not produce tumors in normal C3H mice. DNAs from cell lines established from Ha-ras-induced tumors contained unique Ha-ras sequences in addition to those sequences endogenous to UV-2240 cells. However, the Ha-ras-induced progressor variants did not overexpress the Mr 21,000 protein. The Ha-ra-induced progressor variants produced experimental lung metastasis in both normal C3H and nude mice, although they induced more lung nodules in nude mice than in normal C3H mice. In addition, all four Ha-ras-induced progressor variants produced significantly more experimental lung metastases in nude mice than did the parent UV-2240 cell line. However, both the parental UV-2240 cell line and the Ha-ras-induced progressor variants expressed similar levels of H-2Kk and H-2Dk antigens and were immunologically cross-reactive, as determined by in vitro cytotoxic T-lymphocyte and in vivo immunization-challenge assays. These results indicate that the progressor phenotype of the Ha-ras-induced tumor variants is not due to loss of tumor-specific transplantation or Class I major histocompatibility complex antigens. This implies that some tumor cells can escape the immune defenses of the normal immunocompetent host by mechanisms other than loss of tumor-specific transplantation and Class I major histocompatibility antigens.

Animals↗