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J Mordoh

Publications and source records attributed to J Mordoh.

At least 37 records · Page 2Linked to original sources
PubMed1995

Expression of cathepsin D in primary and metastatic human melanoma and dysplastic nevi.

High levels of cytosolic cathepsin D expression have been associated with poor prognosis in breast cancer node-negative patients. In this work, we provide evidence that three cell lines established from human metastatic melanomas--IIB-MEL-J, IIB-MEL-LES, and IIB-MEL-IAN--express high levels of procathepsin D mRNA. IIB-MEL-J cells secreted into the conditioned media about 30% of the newly synthesized protein, which was active at acidic pH. Melanoma tumors arising in nude mice after injection of the three different cell lines expressed high levels of procathepsin D mRNA. Moreover, 13 human metastatic melanomas expressed variable levels of procathepsin D mRNA. To study the possible association between cathepsin D expression and melanoma development, samples corresponding to 10 primary tumors, 11 metastatic melanomas, 10 dysplastic nevi, 27 nevocellular nevi, and normal melanocytes were studied by immunohistochemistry for cathepsin D-specific staining. We found that cathepsin D was expressed in all of the dysplastic nevi and primary and metastatic melanomas tested but in only 18% of nevocellular nevi (five of 27), whereas normal melanocytes showed no cathepsin D expression. The overall data indicate that cathepsin D is expressed at a high level by melanoma cells, and because of its expression in preneoplastic lesions, it may be associated with melanoma development.

Cathepsin D↗
PubMed1995

Biologic, immunocytochemical, and cytogenetic characterization of two new human melanoma cell lines: IIB-MEL-LES and IIB-MEL-IAN.

Two human melanoma cell lines, derived from metastases of two patients with epithelioid malignant amelanotic melanomas, and designated IIB-MEL-LES and IIB-MEL-IAN, have been established. Both cell lines have been in continuous culture over 2 years and were propagated continuously for 85 and 75 serial passages, respectively. Morphologically, IIB-MEL-LES is composed predominantly of spindle shaped cells, whereas IIB-MEL-IAN grows as a monolayer of cuboid and stellate shaped cells with many rounded cells in suspension. Immunocytochemical studies revealed that both cell lines express S-100 protein, vimentin, and GD3 and GD2 gangliosides but are negative for keratin and collagen. Both cell lines express HLA class I and HLA-DR antigens in variable proportions. The MAGE-1 gene is expressed only by the IIB-MEL-IAN cell line, as revealed by PCR analysis. Cytogenetic analysis of both cell lines revealed abnormal karyotypes; the modal chromosome numbers of IIB-MEL-LES and IIB-MEL-IAN were 48 and 81, respectively. IIB-MEL-LES cells presented rearrangements in chromosomes 1, 14 and X, gains in chromosomes 10, 20, and 21 losses in chromosomes 15 and Y. The most frequent markers observed in IIB-MEL-IAN cells were 7q+, 10p+, 2p+, i(6p), 2q+, and 10q-. Clonal gains were observed in chromosomes 12 and 21, whereas losses were seen in chromosomes 1, 2, 3, 4, 6, 7, 11, and 17. Both cell lines were capable of forming colonies in soft agar and developed tumors when transplanted into nude mice, reproducing and maintaining the characteristics of the original tumors. These cell lines and their xenografts appear to provide useful systems for studying the biology, genetics and histogenesis of human malignant melanoma and could be utilized for the development of melanoma vaccines.

Adult↗
PubMed1995

Atypical androgen receptor in the human melanoma cell line IIB-MEL-J.

To evaluate the presence of androgen receptors in the human melanoma cell line IIB-MEL-J, a Scatchard plot analysis was performed. Cells in culture revealed a single binding component with an apparent dissociation constant (KD) at 37 degrees C of 11 nM and a binding capacity of 326 fmol/mg protein when measured with [3H]-R1881. Competition analysis revealed an atypical relaxation of specificity, since not only androgen (testosterone, dihydrotestosterone [DHT], R1881) and antiandrogen (hydroxy-flutamide [OH-FLU]) competed for [3H]-R1881 binding, but also estradiol, progesterone, and cortisol at 500-fold excess concentration. Binding of [3H]-estradiol and [3H]-R5020 in the absence of unlabeled DHT were completely suppressed in its presence. Immunohistochemistry of androgen receptor with a monoclonal antibody showed that nuclei were vigorously stained. Different doses of flutamide (FLU) and OH-FLU tested on cultured IIB-MEL-J cells in the presence of serum inhibited significantly cell proliferation in a dose-dependent manner. When cells were incubated with 10 nM DHT and 1% charcoal-adsorbed serum, a significant stimulation of growth that was observed was inhibited by 4 microM OH-FLU. DHT stimulation was completely reversed by the antiestrogen tamoxifen. In addition, male nude mice transplanted with IIB-MEL-J tumor were treated with FLU when tumors were palpable. FLU was effective in diminishing tumor growth and increasing survival rate of the animals. As a conclusion, the presence of functional androgen receptors in these cells has been demonstrated by growth inhibition in vitro and in vivo with antiandrogens, and their atypical nature is suggested by binding cross-reactivity and competition studies.

Androgen Antagonists↗
PubMed1993

Role of melanin as a scavenger of active oxygen species.

The protective role of melanin, either synthetic or derived from a metastatic lung melanoma nodule, was studied in terms of its ability to interact with active oxygen species (O2., H2O2, RO., ROO., etc.). Both melanins showed the ability to react with O2.. The superoxide dismutase-like activity corresponds to 21 and 10 U/mg for synthetic and tumor melanin, respectively. The latter value accounts for about 8% of the superoxide dismutase activity of cultured melanoma cells. Neither type of melanin showed catalase-like or glutathione peroxidase-like activity. Both types of melanin reacted with RO. and ROO. radicals as determined by inhibition of the lipid peroxidation reaction of rat liver homogenates. The spontaneous lipid peroxidation of rat liver homogenate was inhibited up to 90% and 80% by synthetic and tumor melanin with half-maximal effects at 2.5 and 5.5 micrograms melanin/ml, respectively. The 2,2-azo-bis-(2 amidino propane) (AAPH)-initiated lipid peroxidation of rat liver homogenate was inhibited up to 30% and 20% by synthetic and tumor melanin, with half maximal effect at 120 and 500 micrograms melanin/ml, respectively. Both types of melanin were able to protect the in vitro inactivation of glucose oxidase, which occurs in the presence of AAPH-generated radicals.

Amidines↗
PubMed1991

The expression of progesterone receptors coincides with an arrest of DNA synthesis in human breast cancer.

Two main models to account for the heterogeneous expression of estrogen receptors (ER) and progesterone receptors (PR) in human breast cancer have been proposed: the clonal model and the stem cell model. The authors previously provided evidence supporting the stem cell model since it was found that most of the proliferating cells in ER-positive (ER+) human breast cancer lack ER and that the ER-negative (ER-) and ER+ subpopulations are interrelated. The authors have analyzed in eighteen ER+/PR+ primary breast tumors the simultaneous expression of ER or PR (by immunohistochemistry) and DNA synthesis (by autoradiography) after 30 minutes of 3H-thymidine incorporation. The authors demonstrated that: (1) the average numbers of ER+ and PR+ cells were similar (36.8 +/- 10.7% and 39.3 +/- 17.6%, respectively); (2) The thymidine-labeling indexes of the ER+, ER-, PR+, and PR- subpopulations were 0.53 +/- 0.69%, 0.74 +/- 0.49%, 0.21 +/- 0.21 and 0.94 +/- 0.54%, respectively; and (3) 75.2% of the DNA-synthesizing cells were ER-, and 88.8% of them were PR-. The authors conclude that the cellular subpopulations expressing ER and PR were not identical, and the expression of PR was associated with a lower rate of cellular proliferation than was ER expression.

Breast Neoplasms↗
PubMed1991

Description of a new human breast cancer cell line, IIB-BR-G, established from a primary undifferentiated tumor.

The establishment of a new human breast cancer cell line (IIB-BR-G) was successful after a previous growth of the cells isolated from a breast primary tumor in a female nude mouse. The IIB-BR-G cell line and the primary tumor do not express estrogen or progesterone receptors. Vimentin and keratin expression were found in the cell line and in the nude mouse tumor. This cell line displays high morphological heterogeneity with atypical multinucleated megacells, and it is capable of anchorage-independent growth and tumor formation in nude mice. The cytogenetic analysis confirmed its human origin and revealed multiple marker chromosomes and extensive chromosomal alterations including rearrangements, gains, losses, isochromosomes, and double minutes (DMs).

Animals↗
PubMed1991

Melanin content and hydroperoxide metabolism in human melanoma cells.

Human melanoma cells were grown to exponential and stationary phases showing melanin contents of 4.2 +/- 0.3 and 11.3 +/- 0.6 micrograms/10(6) cells, respectively. The cells were separated in four subpopulations by a Percoll gradient; the subpopulation of density 1.07 (g/ml) was the most enriched in pigmented cells and produced 28 and 58% of the cells in exponential and stationary phases, respectively. Melanoma cells had similar superoxide dismutase and glutathione peroxidase activities in exponential and stationary phases. Moreover melanoma cells exhibited a higher catalase activity in the stationary phase: whole homogenate and cytosol activities were 7.0 +/- 0.3 and 10.8 +/- 0.6 U/mg protein, whereas in exponential phase the activities were 4.9 +/- 0.1 and 7.6 +/- 0.3 U/mg protein for whole homogenate and cytosol, respectively. The intracellular H2O2 steady-state concentration was 3.3 +/- 0.2 and 2.1 +/- 0.2 microM H2O2 for exponential and stationary phases, respectively. The spontaneous chemiluminescence of the two culture phases was 169 +/- 27 cps/10(6) cells (exponential) and 78 +/- 24 cps/10(6) cells (stationary). The cytotoxicity of H2O2 generated extracellularly by glucose oxidase was determined after 60 min of exposure. IC50 values for exponential and stationary cell cultures were 0.9 and 2.4 mU/ml of glucose oxidase, respectively. The increased catalase activities in the stationary phase as compared with the exponential phase are consistent with the decreased intracellular H2O2, with the decreased spontaneous chemiluminescence, and with the increased resistance to exogenous H2O2.

Catalase↗
PubMed1990

Estrogen receptor gene amplification is found in some estrogen receptor-positive human breast tumors.

The genomic organization of the estrogen receptor (ER) gene has been analyzed in 21 primary human breast cancers and 1 axillary metastasis. No evidence of rearrangements of the ER gene was found in the analyzed tumors. In 6/14 ER-positive tumors a certain degree of amplification of the ER gene, ranging from 1.6 to 3-fold, was detected. No correlation was observed between the level of gene amplification and the amount of ER in the tumors. In the 8 ER-negative tumors analyzed no amplification could be detected. It is concluded that ER gene amplification may be one of the mechanisms underlying the increased ER expression in some breast tumors.

Adult↗
PubMed1990

Differentiating effect of L-tyrosine on the human melanoma cell line IIB-MEL-J.

IIB-MEL-J is a highly heterogeneous newly established human melanoma cell line. The addition of 3 mM L-tyrosine to the culture medium produced (1) a great decrease in the cell growth rate, (2) a loss of the anchor-age-independent growth capacity, and (3) a change in the morphology of the cells to a fibroblastoid aspect. Coincident with these changes, an increase in subpopulations I and II and a decrease in subpopulations III and IV took place. In view of this evidence we consider that the cells have differentiated. The melanin production was not increased by the L-tyrosine treatment, suggesting that differentiation and melanin expression are not strictly correlated.

Cell Adhesion↗
PubMed1989

DNA synthesis in estrogen receptor-positive human breast cancer takes place preferentially in estrogen receptor-negative cells.

The primary breast tumors of 27 patients were analyzed for the expression of estrogen receptors (ER) and DNA synthesis. Seventeen tumors were ER-positive, and the simultaneous expression of ER and DNA synthesis could be analyzed in 14 ER-positive tumors. DNA synthesis was measured through the thymidine labeling index (TLI). ER expression was detected by immunohistochemistry with monoclonal antibodies. In these tumors, 38.6% +/- 13.1% of the cells were ER-positive (average TLI = 0.60% +/- 0.70%), as opposed to the presence of 61.4% +/- 13.1% of ER-negative cells (average TLI = 0.65% +/- 0.53%). In 12 of 14 tumors, both ER-positive and ER-negative cells were found to be engaged in DNA synthesis, whereas in two tumors only ER-negative cells were synthesizing DNA. On the basis of the TLI and the proportion of ER-negative and ER-positive cells in the total population, it is suggested that the ER-positive and ER-negative compartments are interrelated in most tumors. In five tumors, the ER-negative compartment would be a precursor of the ER-positive segment, whereas in six tumors the ER-positive segment appears to be a precursor of the ER-negative one. In three tumors, no evidence of an interrelationship between both segments could be found. In the 14 tumors analyzed, it also was found that 69.1% +/- 21.3% of the DNA-synthesizing cells were ER-negative; this probably accounts for the temporary remissions observed after hormonal treatment in breast cancer.

Breast Neoplasms↗
PubMed1988

In vitro analysis of the cellular proliferative response to 17-beta-estradiol of human breast cancer.

In human breast cancer the proliferating cells appear to differ from those containing estrogen receptors (ER) as shown by studies on isolated cellular subpopulations. In this paper the in vitro effect of 17-beta-estradiol on cell proliferation in 30 primary breast tumors was studied. The effect of several estradiol concentrations was assayed, and the influence of diethylstilbestrol, tamoxifen, and nafoxidine was also tested. The response to these compounds was measured through the thymidine labeling index (TLI). When exposed to 10(-9) mol/l and 10(-8) mol/l estradiol, 14 of 19 ER-positive tumors and six of 11 ER-negative tumors were induced to further proliferate. The TLI increase over the control was 219% (P less than 0.05) at 10(-9) mol/l E2 and 258% (P less than 0.05) at 10(-8) mol/l E2 for ER-positive tumors, and 233% (0.1 less than P less than 0.2) at 10(-9) mol/l E2 and 321% (0.1 less than P less than 0.2) at 10(-8) mol/l E2 for ER-negative tumors. The addition of diethylstilbestrol and antiestrogens in vitro inhibited, to varying degrees, the estradiol-induced increase in the TLI irrespective of the ER-status. The response to E2 was correlated with the expression of the ras p21 protein and carcinoembryonic antigen. It was found that the ras p21 protein is preferentially expressed in ER-negative tumors, the opposite being true for carcinoembryonic antigen. The ras p21 protein is preferentially expressed in those ER-positive tumors that do not respond to estradiol with an increase in the TLI.

Breast Neoplasms↗
PubMed1988

Effect of estradiol and tamoxifen on the anchorage-independent growth of the subpopulations derived from MCF-7 breast carcinoma cells: cytogenetic analysis of the stem cell subpopulation.

The MCF-7 breast carcinoma cell line can be separated by Percoll density gradient centrifugation into several subpopulations, A to F, one of which (E) has been previously suggested to be highly enriched in stem cells. The anchorage-independent growth of the different fractions and its sensitivity to estradiol (E2) and tamoxifen (TAM) was assayed. The anchorage-independent growth capacity of the different fractions was E greater than A greater than B greater than D greater than C,F. The E fraction had the highest clonogenic index (6.62 +/- 1.18) and was unaffected by E2 or TAM. The karyotypic analysis of the E fraction revealed features similar to those of the unfractionated cell line. It is suggested that the high growth rate of fraction E is due to an enrichment in stem cells and not to the existence of a different clone.

Breast Neoplasms↗
PubMed1987

Subpopulations of MCF7 cells separated by Percoll gradient centrifugation: a model to analyze the heterogeneity of human breast cancer.

Exponentially growing MCF7 human breast cancer cells were separated in Percoll gradients into six different fractions of increasing density (A to F). These fractions could be subcultured and were found to contain different cellular subpopulations as defined by the following criteria: ability to generate other cellular subpopulations; growth rate; DNA synthesis; and expression of estrogen receptors, ras oncogene-encoded protein p21, and carcinoembryonic antigen. One of the minor fractions (E), which contained about 5% of the total cell number, appeared to contain the stem cells, on the basis of the following criteria: (i) its ability to reproduce the other cellular subpopulations, (ii) its high rate of growth and DNA synthesis, and (iii) the inability of the other subpopulations to generate it. The most differentiated subpopulation appeared to be the densest one (F), since it was the slowest growing and appeared to be the end point of the other subpopulations.

Breast Neoplasms↗
PubMed1986

Determination of DNA synthesis, estrogen receptors, and carcinoembryonic antigen in isolated cellular subpopulations of human breast cancer.

Primary breast adenocarcinomas obtained from ten patients were enzymatically digested using collagenase (1 mg/ml), hyaluronidase (1 mg/ml), elastase (0.1 mg/ml) and DNAse (0.2 mg/ml). The tumor cells were labeled with 3H-thymidine and, in some cases, with 3H-estradiol. The isolated cells were submitted successively to a Ficoll-Hypaque and a bovine serum albumin gradient, from which 12 fractions were obtained. In each fraction, several characteristics were determined: carcinoembryonic antigen (CEA), thymidine (dThd) incorporation, and estrogen receptors (ER). Three main cellular subpopulations were characterized: An intermediate density subpopulation (1.046-1.054 g/ml), in which the proliferating cells are concentrated. In this subpopulation a small number of CEA-positive cells are present, but ER containing cells are virtually absent. A high-density, small cell subpopulation that concentrates most of the ER-containing cells. This subpopulation lacks proliferating cells, but CEA-containing cells are abundant. A low-density subpopulation, lacking proliferating cells and with scarce ER-positive cells, although CEA-positive cells are frequent. These findings strongly suggest that proliferating cells lack ER.

Adenocarcinoma↗
PubMed1986

Metabolism of phosphatidyl-dCMP in sarcoma 180 cells. Effect of chlorpromazine, phosphatidic acid and inositol.

The synthesis and degradation of phosphatidyl-dCMP was studied in intact and permeabilized Sarcoma 180 cells as well as in isolated nuclei. It was verified that chlorpromazine greatly enhanced phosphatidyl-dCMP synthesis and completely abolished its hydrolysis in intact cells. The former effect was reversible and was partially lost upon permeabilization or isolation of nuclei. Phosphatidic acid also increased liponucleotide synthesis and the combination of phosphatidic acid with chlorpromazine was not additive. When inositol was added to cells which had accumulated phosphatidyl-[3H]dCMP, the recovery of radioactivity in the organic phase decreased; this effect was dose-dependent and specific for inositol, and was accompanied by an increased release of [3H]dCMP to the cell medium. In isolated microsomes, addition of Ptd-dCMP determined incorporation of [3H]inositol into phosphatidyl-inositol. These results strongly suggest that phosphatidyl-dCMP is utilized for the synthesis of phosphatidyl-inositol.

Animals↗
PubMed1986

Characterization of lysosomal acid phosphatase from normal and malignant mammary tissue.

Acid phosphatase (EC 3.1.3.2) isoenzyme 3 was purified from normal and malignant human mammary tissue and its properties in each were compared. The relative molecular mass of each was 53 000, as measured by sodium dodecyl sulfate gel electrophoresis. Several phosphomonoesters are good substrates for the isoenzymes, whereas organic and inorganic pyrophosphates and phosphoryl choline are hydrolyzed very slowly or not detectably. The optimum pH for interaction of these isoenzymes with p-nitrophenyl phosphate as substrate ranges from 3.5 to 4.5. L-(+)-Tartrate is a very strong inhibitor, Ki = 0.028 +/- 0.04 mmol/L (mean +/- SE), as are mercuric and fluoride ions in low concentrations. We conclude that type 3 isoenzymes obtained from normal and malignant tissue are very similar, though the malignant tissue appears to have a greater proportion of this type than does normal tissue.

Acid Phosphatase↗