IN VITRO PROLIFERATION AND IN VIVO MALIGNANCY OF CELL LINES SIMULTANEOUSLY DERIVED FROM A CHEMICALLY-INDUCED HETEROGENEOUS RAT MAMMARY TUMOR (original) (raw)
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In Vitro Cellular and Developmental Biology--Animal, 2000
In order to isolate, characterize, and establish culture cell lines with different diagnostic and prognostic significance, derived from multiclonal neoplasms, a ductal infiltrating mammary tumor was induced in rats by 7,12-dimethylbenz[a]anthracene. Clones with different DNA/protein content, being the DI of 1.16, 1.30, and 1.60, respectively, were observed in the primary tumor. Biparametric flow cytometry suggested that the clone at 1.30 is made up of two subpopulations with different protein and slightly different DNA contents. The culture, after a few passages, exhibited the presence of aneuploid cells and the absence of diploid components, demonstrating that only tumor cells survived. The limiting dilution method gave rise to four lines with DI of 1.16, 1.25, 1.30, and 1.50; a mean chromosome number of 45, 46, 47, and 88, respectively; and different morphological and uhrastructural features. These characteristics were stable during the experimental procedure, that is, for about 20 passages. Conversely, the detection of cytoskeletal proteins indicated that the tumor epithelial cells underwent early dedifferentiation into sarcoma-like cells showing markers of stromal cell type and thus exhibiting phenotypic instability in vitro, a feature reported in many advanced human breast cancers in vivo. In conclusion, this cellular model represents the in vivo situation and appears suitable for in vitro studies of tumor cell characteristics and might be used to predict clinical behavior.
In Vitro Cellular and Developmental Biology-Animal, 2003
Isolation and growth of malignant cells from solid tumors have often met with disappointing results. Consequently, we have developed a cell culture methodology based on ex vivo explantation of tumor tissue, with subsequent monolayer cell outgrowth. In an attempt to assess methods for detection of malignant cells in these cultures, we analyzed and compared the results of cytopathology, growth in soft agar, and detection of telomerase activity with those of standard immunohistochemistry (IHC) techniques for the detection of cytokeratins, tumor marker p53, and proliferation marker Ki-67. The sensitivity of detection of malignant cells was 85% (22/26) for cytopathological examination, 30% (3/10) for soft agar growth, and 100% (12/12) for detection of telomerase activity. From these data, we concluded that both cytopathological examination and assessment of telomerase activity contribute to the detection of malignant cells in primary cultures of human solid tumors, whereas growth in soft agar was not a good indicator of malignant cells. Although not specific for malignant cells per se, IHC detection for epithelial cell cytokeratins showed a high degree of sensitivity (100%, 23/23), whereas the sensitivity for detection of tumor marker p53 and proliferation marker Ki-67 was 30% (7/ 23) and 70% (16/23), respectively. These data also provide proof that malignant tumor ceils, derived from a diverse number of human solid tumors, can be isolated and grown in primary cell culture.
A comparison of three in vivo assays for cell tumorigenicity
PubMed, 1974
The cortisonized adult hamster, the antithymocyte-treated newborn hamster, and the antithymocyte globulin-treated monkey were compared as in vivo test systems for the tumorigenic potential of cells. The newborn hamster and monkey systems were more consistent in allowing the expression of tumors than was the cortisonized hamster when each of three human tumor cell lines was assayed. Cells derived from normal tissues failed to show evidence of tumorigenicity in any of the three animal systems.
Differential characteristics of two newly established human breast carcinoma cell lines
Cancer research, 1985
Two human breast carcinoma cell lines, EP and MW, were established in culture from malignant pleural effusions. In addition to producing tumors in antithymocyte serum-immunosuppressed mice, both cell lines showed epithelial characteristics and anchorage-independent growth in soft agar. EP and MW differed in morphology (spindle-shaped versus round), chromosomal mode (hyperdiploid versus near triploid), estrogen receptor content (43.8 versus 5.1 fmol/mg protein), cloning efficiency (0.24 versus 15%), and activities (milliunits/10(6) cells) of creatine phosphokinase (25.7 versus 62.6) and lactate dehydrogenase (346.7 versus 778.5). Electron microscopy revealed that MW cells had more perinuclear filamentous material and more frequent intracytoplasmic vacuole formation than did EP cells. While having no effect on MW cells at the concentrations studied (10(-5) to 10(-11) M), beta-estradiol (10(-7) M) stimulated the growth of EP cells by 106% over the hormone-depleted control. In a variety...
Mechanisms involved in the induction of malignant cell differentiation
Advances in Enzyme Regulation, 1986
Cancer appears to be a disease of altered maturation, with changes in genetic expression leading to a situation in which the physiological regulation of cellular proliferation and maturation are altered. Environmental factors as well as defined chemical agents have been demonstrated to have the capacity to convert neoplastic cells to end-stage forms with a finite life span through a process characteristic of cellular maturation. The correction of genetic defects by these inducers of differentiation does not appear to be required; the critical feature is that the differentiated cells assume a state in which they no longer possess the capability for continued cellular replication. The extrapolation of these advances, accomplished in experimental systems, to clinical practice should yield significant decreases in the neoplastic cell burden without the degree of morbidity produced by aggressive therapy with cytodestructive agents, especially when employed in multidrug combinations. The ultimate introduction of differentiation as a therapeutic approach to cancer treatment if attained, however, will require a variety of principles to be established, so that optimum efficacy may be obtained from each agent, the fabrication of new agents with major changes in the ratio of the concentrations required to produce cytotoxicity relative to those necessary to initiate maturation is attained, and the elucidation of non-antagonistic combinations of differentiation inducing agents with or without cytotoxic drugs is achieved to combat the problem of tumor cell heterogeneity.
Selection of low frequency tumor cells from cell culture by growth in nude mice
Cancer Genetics and Cytogenetics, 1991
"/'issue cultures of tumor cells are frequently utilized to characterize chromosomal changes when direct cytogenetic preparations on tumors fail. The present study demonstrates that chromosomal markers found in direct tumor preparations can become undetectable in cell culture at variable rates presumably because of overgrowth of normal cell components in the culture. Injection of cultured tumor cells into nude mice followed by direct chromosomal preparations on the resulting nude mouse tumors can be used to select cells with the original tumor karyotype. This is true even when the tumor cell frequency in the culture is so low that they are not found in routine chromosomal preparations of the cultured cells. This technique can thus complement tissue culture findings and provide additional useful information about the original karyotype in cases where direct chromosomal preparations from tumors have failed.
In Vitro Cellular & Developmental Biology - Animal, 1992
To establish a model system for preclinical radioimmunotherapy studies, attempts were made 1o graft 16 different human breast carcinoma cell lines into BALB/c nu/nu (nude) mice. Nine produced serially transplantable tumors growing at a variable rate, whereas seven failed to do so. Conversely, three new cell lines were established in monolayer culture from transplantable human breast tumors in nude mice. Twelve selected tumors and their corresponding cell lines were characterized for DNA ploidy, % S-phase, and breast epithelial mucin expression by immunohistochemistry and flow cytometry. A wide diversity of these cellular characteristics were found in that each tumor was unique and distinct from the others. DNA ploidy differed among the tumors but was not affected by switching between in vitro to in vivo growth. Some tumors expressed similar levels of the breast mucin both in vitro and in vivo, whereas most expressed lower levels as transplantable tumors. There was a good correlation between immunohistochemical and flow cytometrie determination of surface and cytoplasmic mucin expression, and with both techniques estrogen and progesterone receptor positive tumors had significantly higher levels of mucin expression than receptor negative tumors. These 12 transplantable breast tumors, with their corresponding cell lines, provide an excellent model system for testing radioimmunotherapy and other therapeutic reagents because they exhibit diverse phenotypic characteristics that represented a mini-population of breast cancer patients' tumors, allowing assessment of the effect of therapy when confronted with different breast tumors' genotype and phenotype.
British Journal of Cancer, 1991
Cell kinetics have been shown to be an important predictor of clinical evolution of operated breast cancer. We established a method for the estimation of the proliferative activity of tumour cells obtained by fine needle sampling without aspiration (FNS), using simultaneously S-phase fractions (SPF) measured on DNA histograms and 5-bromodeoxyuridine (BrdU) labelling index (BLI) measured by flow cytometry. Biparametric BrdU/DNA flow cytometry could be performed in 122 of 189 (65%) consecutive patients. The mean BLI of the cytologically malignant FNS (118) was of 3.0 and the median of 2.2%. One hundred and forty-eight DNA histograms (78%) were suitable for SPF analysis, of which 141 presented-malignant cells, showing a mean of 4.5 and a median of 3.5%, comparable to BLIs. These results were obtained from fluorescence peak area histograms with doublet discrimination and background subtraction allowing the measurements of SPFs as low as 0.4%. An excellent correlation was thus observed between-BLIs and SPFs, for the 94 cases for which both results were available (r = 0.85). Infrequent discordances (9%) were noted with SPFs considerably higher than BLIs. Seven patients had three consecutive FNS of their tumour at weekly intervals before treatment. Some variability in the proportions of multiple subpopulations of tumour cells was observed on the DNA histograms. In contrast, proliferation indices (SPF or BLI) were reproducible, suggesting homogeneous growth rates. We conclude that an estimation of the proliferative activity of breast tumours at any stage of the disease is possible routinely by SPF and/or BLI analysis of FNS. At least one quantitative proliferation index could be obtained for 91% of patients.