Biomedical subjects

J E Price

Publications and source records attributed to J E Price.

At least 55 records · Page 3Linked to original sources

PubMed1990

The use of a genotypic marker to demonstrate clonal dominance during the growth and metastasis of a human breast carcinoma in nude mice.

When a mixture of 11 clones of a human breast carcinoma (MDA-MB-435)--each clone transfected with pSV2neo and identified as having a unique insertion site of the gene--was injected into nude mice, the resulting tumors were found to contain only one clone (Neo 24). This clone, identified by the unique restriction fragments on Southern blot analyses, was also found in metastases recovered from the lungs and lymph nodes of the animals. The individual clones showed no differences in in vitro growth, while in vivo the Neo 24 cells produced the largest tumors. Thus, one explanation for the observed clonal dominance in this study could be the more rapid growth in vivo of the Neo 24 cells. This study illustrates how an introduced selectable gene marker can be used in lineage studies of human tumor cell populations.

Animals↗

PubMed1990

Tumorigenicity and metastasis of human breast carcinoma cell lines in nude mice.

There are few reports describing experimental models of the growth and metastasis of human breast carcinomas. This article discusses the tumorigenic and metastatic properties of two estrogen receptor-negative breast carcinomas injected into nude mice. Tumor growth in the mammary fatpad (m.f.p.) and the subcutis was compared in female nude mice. The injection of 10(5) viable cells of two human breast carcinoma cell lines (MDA-MB-231 and MDA-MB-435) gave a 100% tumor take rate in the m.f.p., whereas only 40% of the s.c. injections produced tumors and these occurred several weeks after the appearance of the m.f.p. tumors. Thus, the m.f.p. of nude mice is a favorable site for the growth of human breast carcinomas. MDA-MB-435 tumors produced distant metastases in 80% to 100% of recipients. The most common sites for metastasis were the lymph nodes and lungs, with a lower incidence of metastases in muscle (chest wall and thigh), heart, and brain. New variant cell lines were isolated from metastases in the lungs, brain, and heart. All the cell lines were tumorigenic in the m.f.p., and the lung- and heart-derived metastasis lines produced slightly more lung metastases than the original cell line. However, the brain metastasis variant produced significantly fewer lung metastases. Intravenous inoculation of the spontaneous metastasis-derived cell lines produced few lung colonies. Only cell variants isolated from experimental lung metastases showed enhanced lung colonization potential when reinjected i.v. Our results suggest that the estrogen receptor-negative MDA-MB-435 cell line injected in the m.f.p. of nude mice could be a valuable tool for analysis of the cellular and molecular basis of the metastasis of advanced breast cancer.

Animals↗

PubMed1990

Studies of human breast cancer metastasis using nude mice.

Athymic nude mice have been used in recent years to study the biology of human tumors and to assess therapeutic responses in vivo rather than just in vitro. Some human tumors metastasize in nude mice, providing model systems for analyzing various aspects of the metastatic phenotype of human neoplasms. For breast carcinomas, however, the tumor-take rate of surgical specimens is low, and only a limited number of cell lines proliferate in nude mice. The site of injection of the breast carcinoma cells is important; tumors grow at a lower inoculum dose and with shorter latent intervals after implantation in the mammary fatpad of nude mice than after injection in the subcutis. One breast carcinoma cell line, MDA-MB-435, metastasizes from mammary fatpad tumors to lymph nodes, lungs, and other visceral organs. In contrast, two other cell lines show lower metastatic ability. Intravenous injection and injection of tumor cells into the internal carotid artery of nude mice produces lung and brain metastases, respectively, thus simulating the arrest and organ colonizing steps of the metastatic cascade. These different techniques demonstrate the potential of experimental studies of human breast cancer growth and metastasis using nude mice.

Animals↗

PubMed1990

The biology of cancer metastasis.

The formation of a metastasis entails a complex sequence of events with the end result dependent on the interaction of malignant cells with host factors. Intrinsic properties of the metastatic tumor cells, including production of proteolytic enzymes, cell surface properties, adhesiveness, and the ability to grow in a distant organ environment, act in concert to influence the tumor cells' interactions with host cells in forming metastases. Life-threatening metastases are formed only by those tumor cells that have survived all steps in a process that has been shown in many experimental studies to be a highly selective event. The results of studies on the distribution of radiolabelled mouse melanoma cells injected into syngeneic mice support the concept that the fate of tumor cells released into the bloodstream is determined by sequential and selective events, and introduces a third regulatory factor. Cells endowed with metastatic properties, isolated by cloning a heterogeneous tumor or selected from a metastasis, have a higher probability of forming metastases than cells not so endowed, yet this probability is not 100%. Metastasis should thus be considered as a selective, sequential and stochastic process. Interruption of the process at any stage will prevent the formation of metastatic disease. Hence, a better understanding of the metastatic process will provide the basis for rational approaches for the prevention or destruction of this most fatal aspect of cancer.

Animals↗

PubMed1990

Regional growth of different human melanomas as metastases in the brain of nude mice.

Cells from eight different human melanomas and two murine melanomas were injected into the internal carotid artery of anesthetized nude mice. Although all were injected by the same route, particular melanomas produced lesions in different regions of the brain. Two melanoma cell lines isolated originally from brain metastases in patients produced metastases predominantly in the brain parenchyma. In contrast, melanoma cells from subcutaneous or lymph node metastases produced more lesions in the meninges, choroid plexus, and ventricles than in the brain parenchyma. All of the melanomas grew in the brain after a direct intracerebral injection. The pattern of brain metastasis did not correlate with tumorigenicity per se or with the ability of the melanomas to grow in the lungs of nude mice. Two mouse melanomas showed different patterns of experimental metastasis after internal carotid artery injection, with one growing predominantly in the parenchyma and the other more frequently in the meninges and choroid plexus. The growth pattern of human melanoma metastasis in the brain of T cell-deficient nude mice suggests that it is determined by properties unique to each tumor interacting with the host's organ microenvironment.

Animals↗

PubMed1989

Unique patterns of brain metastasis produced by different human carcinomas in athymic nude mice.

The purpose of this study was to develop an in vivo model to study the growth pattern and biological behavior of brain metastases produced by different human carcinomas. To do so, human tumor cells from 8 different carcinomas of the colon, breast, kidney and lung were injected into athymic nude mice either by a direct intracerebral route or into the internal carotid artery. All carcinoma cells invaded through the blood-brain barrier and produced progressively growing lesions in the brain parenchyma. Unique patterns of growth were discernible among the carcinomas. Human colon carcinomas produced multiple lesions that spread by extension. Lung carcinoma cells produced widespread lesions throughout the brain. A very high degree of vascularization was associated with lesions produced by renal-cell carcinoma. The influence of estrogen on the growth of estrogen-receptor-positive human breast carcinoma cells was well demonstrated in this model. We conclude that the athymic nude mouse can be a useful model for studies of the biology and perhaps therapy of brain metastases produced by human carcinoma cells.

Animals↗

PubMed1989

Augmentation of antiproliferative activity of interferon alfa against human bladder tumor cell lines by encapsulation of interferon alfa within liposomes.

Present therapy for human bladder cancer includes the intravesical administration of antiproliferative agents, such as recombinant human interferon alfa (IFN-alpha). The administration of cytotoxic molecules encapsulated in liposomes could provide a more efficient method for such therapy. Therefore, we determined whether encapsulation of the recombinant human IFN-alpha hybrid BBDD within liposomes will produce antitumor effects against the human bladder cancer cell line 253J superior to those observed with free IFN-alpha. Adherent cells were cultured in medium alone, in medium containing different concentrations of IFN-alpha, or in medium containing multilamellar liposomes (phosphatidylcholine-phosphatidylserine at a molar ratio of 7:3) that encapsulated saline or IFN-alpha. Cell growth was determined 96-120 hours later. Additional control groups consisted of target cells cultured with free IFN-alpha or with IFN-alpha plus liposomes containing saline. Cytostasis mediated by free IFN-alpha alone or IFN-alpha in the presence of liposome-saline was identical and ranged from 0%-30% (10 IU/mL) to 45%-70% (1,000 IU/mL). Liposomes containing saline produced no effects. Liposome-encapsulated IFN-alpha produced significantly greater growth inhibition than free IFN-alpha: 40%-70% (10 IU/mL) and 80%-90% (1,000 IU/mL), respectively. Moreover, a 253J variant subline selected for resistance to free IFN-alpha was sensitive to IFN-alpha presented in liposomes. These data suggest that the encapsulation of antiproliferative agents such as IFN-alpha in liposomes can improve therapeutic results.

Carcinoma, Transitional Cell↗

PubMed1989

Correlation of growth capacity of human tumor cells in hard agarose with their in vivo proliferative capacity at specific metastatic sites.

The purpose of this study was to determine whether the degree of anchorage-independent growth of human tumor cells in increasing concentrations of agarose correlated with the capacity of the cells to produce experimental metastases in nude mice. Human melanoma, breast carcinoma, and colon carcinoma cells from parental lines and variants selected in vivo for metastasis and in vitro cloned lines were plated into medium containing 0.3%, 0.6%, 0.9%, or 1.2% of agarose. These cells were also injected into nude mice: intravenously for melanoma, into the mammary fat pad for breast carcinoma, and into the spleen for colon carcinoma. Production of tumor cell colonies in dense agarose (greater than 0.6%) correlated with production of experimental metastases in the lung (melanoma, breast carcinoma) or liver (colon carcinoma). We conclude that the degree of anchorage-independent growth of tumor cells can predict their biological behavior and metastatic potential in vivo. Thus, this technique may be useful for the isolation of metastatic cells from heterogeneous human neoplasms.

Animals↗

PubMed1989

Metastatic potential of cloned murine melanoma cells transfected with activated c-Ha-ras.

We sought to determine whether the transfection of tumorigenic but not metastatic cells with the activated c-Ha-ras oncogene was invariably associated with acquisition of the metastatic phenotype. Three clonally derived lines of the K-1735 murine melanoma, characterized as nonmetastatic or poorly metastatic, were transfected with plasmids containing the 6.6-kilobase BamHI fragment of the mutant human c-Ha-ras gene and the neo gene, that confers resistance to neomycin (pSV2neoEJ). Cells transfected with pSV2neo, a plasmid containing the neo gene, served as controls for the procedure of Polybrene-mediated transfection. All cell lines were injected into syngeneic C3H/HeN and into athymic mice, and the results were compared with those produced by highly metastatic K-1735 M-2 cells. Although the pSV2neoEJ-transfected cells produced more rapidly growing s.c. tumors than the control cell lines did, the incidence of spontaneous metastasis was not increased. Following i.v. inoculation, the c-Ha-ras transfectants were retained in lung vasculature in greater proportions than pSV2neo counterpart transfectants were. The c-Ha-ras transfectants also produced significantly more lung tumor colonies, which grew faster than the few lung tumor colonies in mice given injections of control melanoma cells. We concluded that transfection of the activated c-Ha-ras oncogene into nonmetastatic K-1735 melanoma cells leads to accelerated tumor growth in vivo and can confer the ability to form lung colonies after i.v. injection but not the ability to metastasize from a primary s.c. tumor.

Animals↗

PubMed1989

Tumor cell dissemination patterns and metastasis of murine mammary carcinoma.

Quantitative studies on the distribution kinetics of isotope-labeled cells from spontaneous murine mammary tumors injected intravenously or arterially showed that cells were rapidly distributed to all organs examined and indicated that the distribution patterns of metastases from such tumors are not primarily determined by the dose of cells delivered to each organ. The preferential colonization of certain organs is therefore considered to depend as much on differential survival and growth of the disseminated tumor cells in unfamiliar metabolic microenvironments, as on vascular sieving effects in organ capillary networks. Further experiments involved transplantation of pieces of nonpulmonary tissue containing trapped mammary tumor cells into syngeneic mice, followed by observation of the animals for several months. From these studies it is concluded that the absence of tumor colonies in extrapulmonary sites after i.v. inoculation is due to their inability to thrive in the organs concerned and not to early death of the original host from heavy pulmonary tumor growth. These results provide further evidence strengthening the conclusion emerging from several independent lines of investigation (Potter et al., Invasion Metastasis, 3: 221-233, 1983; Tarin et al., Cancer Res., 41: 3604-3609, 1981; Tarin et al., Cancer Res., 44: 3584-3592, 1984; Horak et al., J. Natl. Cancer Inst., 76: 913-922, 1986; Nicolson et al., Int. J. Cancer, 38: 289-294, 1986; Naito et al., Invasion Metastasis, 7: 16-29, 1987) that the growth of disseminated tumor cells is inhibited or even abrogated by many of the organs in which the cells sequester after vascular dissemination.

Animals↗

PubMed1989

Low incidence of tumourigenicity in agarose colonies from spontaneous murine mammary tumours.

In these experiments individual colonies growing in agarose seeded with monocellular suspensions from freshly disaggregated naturally-occurring mouse mammary tumours, induced by the murine mammary tumour virus (MMTV), were reimplanted into mammary fat pads of virus-free mice. It was found that only a small proportion of these colonies generated tumours and that the implantation of multiple colonies in each site did not result in disproportionate, synergistic, increase in tumour takes. It was also observed that the proportion of colonies which were tumourigenic on reimplantation differed for each donor tumour and represented only a small fraction of the total cell population (0.001%-0.1%). However, this value was significantly higher in tumours which produced large numbers of deposits in lung colony assays following i.v. injections, than in tumours of low pulmonary colonisation potential. A point of particular interest was that tumours derived from agarose colonies of spontaneously metastatic donor tumours were substantially more spontaneously metastatic themselves than those from nonmetastatic donors, indicating that this property is heritable through numerous cell divisions, manipulations in vitro and transplantation procedures. From these results it is concluded that measurement of clonogenicity in agar is useful as an index of the capability of a tumour to propagate itself and to colonise new sites, but that individual agarose colonies are not all the progeny of potentially immortal stem cells.

Animals↗

PubMed1989

A pilot study of three potential vaccines for leprosy in Bombay.

Three vaccines, BCG Glaxo alone (vaccine A), BCG Glaxo plus 10(7) killed Mycobacterium vaccae (vaccine B), and BCG Glaxo plus 10(7) killed M. leprae (vaccine C), were given to groups of selected children. The effects of these vaccines on subsequent quadruple skin testing 1-3 years after vaccination were compared. All three vaccines equally and significantly (p less than 0.00001) increased positivity to tuberculin, but only vaccine B was found to significantly enhance development of skin-test positivity to leprosin A (p less than 0.002). The data support the evidence previously obtained in rural Iran that the combination of BCG with killed M. vaccae is likely to be a better vaccine for leprosy than is BCG alone.

Adolescent↗

PubMed1988

Detection and identification of activated oncogenes in human skin cancers occurring on sun-exposed body sites.

High-molecular-weight DNA isolated from eight fresh human skin cancers occurring on sun-exposed body sites were assayed for their ability to transform NIH 3T3 cells. A cotransfection protocol using pSV2-neo DNA, which confers resistance to the antibiotic G418, was used to select cells that had taken up the transfected DNA. About 2 weeks after transfection, G418-resistant colonies were pooled and injected s.c. into athymic nude mice. The NIH 3T3 cells transfected with DNA from six of the human skin cancers induced tumors in nude mice. DNAs from all six tumor cell lines contained human alu sequences. Southern blot hybridization with ras-specific probes revealed that DNAs from the four alu-rich tumors contained the human Ha-ras oncogene, in addition to that of the NIH 3T3 controls. In contrast, DNAs from the other two tumors did not contain any of the known oncogenes tested, except those endogenous to NIH 3T3 cells. DNAs from three of four first cycle tumorigenic transformants gave rise to morphologically transformed foci when assayed in a second cycle of transfection. DNAs from all three secondary transformants contained discrete human alu sequences, and in addition, contained Ha-ras sequences similar to those present in their respective primary transformants. Interestingly, DNA from both primary and secondary transformants of one particular human squamous cell carcinoma contained highly amplified copies of the Ha-ras oncogene. These results suggest that activation of the Ha-ras oncogene may be common in human skin cancers originating on sun-exposed body sites. Further characterization of the Ha-ras oncogenes present in these human skin cancers may provide information on the molecular mechanisms by which UV radiation of the sun induces human neoplasms on exposed body sites.

Aged↗

PubMed1988

Influence of organ microenvironment on pigmentation of a metastatic murine melanoma.

The purpose of these studies was to investigate the relationship of the host microenvironment to the metastatic and pigmented phenotypes of the SW-1 variant of the murine K-1735 melanoma. The SW-1 subline was isolated from an amelanotic lung metastasis in a C3H/HeN mouse given an s.c. injection of the K-1735 melanoma. Cells of this line were highly metastatic and produced tumor deposits in many organs. In all sites except the brain, these lesions were predominantly amelanotic. K-1735 SW-1 cells were isolated from metastases in various organs and subsequently reinoculated into normal syngeneic recipients. Whereas the metastatic phenotype remained stable and thus was heritable, pigmentation was unstable and appeared to be modulated by the site of tumor growth. Further differences in the phenotype of K-1735 SW-1 cells growing in vivo and in culture were revealed by assays for tyrosinase activity. K-1735 SW-1 cells growing in culture did not produce melanin nor did they respond to agents that can stimulate melanin production in another mouse melanoma, the B16 line. K-1735 SW-1 cells do not, however, lack tyrosinase, since these cells are capable of producing melanin when growing in certain organs in vivo. We conclude that the host organ environment may influence a phenotype of malignant melanoma cells, i.e., pigmentation. These findings also suggest caution when extrapolating the results of in vitro biochemical assays to properties of tumor cells growing in vivo.

Animals↗

PubMed1988

Simultaneous transfer of tumorigenic and metastatic phenotypes by transfection with genomic DNA from a human cutaneous squamous cell carcinoma.

High-molecular-weight genomic DNA isolated from a human cutaneous squamous cell carcinoma (AS) was assayed for its ability to induce tumorigenic transformation of NIH 3T3 cells. Subcutaneous injection of NIH 3T3 cells cotransfected with DNAs from AS tumor and pSV2-neo plasmid not only induced tumors at the site of injection, but also metastasized spontaneously to the lungs in 100% of nude mice injected. DNA isolated from a representative primary tumor and a metastasis was again used in a second round of transfection. Injection of secondary transfectants into nude mice again resulted in induction of both subcutaneous tumors and spontaneous long metastases. Southern blot hybridization with ras-specific probes revealed that DNA from both primary tumors and metastases induced by AS tumor DNA contained highly amplified Ha-ras oncogene. Furthermore, DNAs from secondary tumors and metastases induced by DNA from a primary tumor and a metastasis also contained similar highly amplified Ha-ras oncogene. These results suggest that the amplified Ha-ras oncogene may be responsible for induction of both tumorigenic and metastatic phenotypes in NIH 3T3 cells transfected with DNA from AS tumor.

Aged↗

PubMed1988

Tumorigenicity and metastatic behavior in nude mice of two human squamous cell carcinoma lines that differ in production of the cytokine ETAF/IL-1.

The purpose of these studies was to determine whether the production of the cytokine epidermal cell thymocyte-activating factor (ETAF) by human squamous cell carcinoma (SCC) cells correlated with their tumorigenicity and metastatic potential in athymic nude mice. Cells of the human SCC line A431 produced rapidly growing subcutaneous tumors, few experimental lung metastases, and low levels of ETAF activity in vitro. In contrast, cells of the SCC Colo-16 line produced slower growing subcutaneous tumors, high numbers of experimental lung metastases, and a high level of ETAF activity in culture supernatants. The apparent relationship between production of ETAF and experimental metastasis formation was not consistent. Clonal populations of the SCC A431 and Colo-16 were isolated in vitro. The clones of Colo-16 varied in their ability to produce experimental metastases and in production of ETAF in vitro. However, the levels of ETAF production did not correlate with the propensity of the SCC cells to produce experimental metastases. We conclude that while the growth and metastasis of human SCC in nude mice may benefit from production of the cytokine ETAF, the ETAF production per se is not invariably linked with the capability of the SCC cells to metastasize.

Animals↗

PubMed1987

Phenotypic diversity of murine B16 melanoma detected by anti-B16 monoclonal antibodies.

A panel of monoclonal antibodies (MoAbs), produced against the murine B16 melanoma, has been used to characterize its phenotypic diversity. Six MoAbs that did not bind to primary cultures of kidney, brain or liver, spleen cells, thymocytes, 3T3 fibroblasts, melanin, or transferrin receptors were selected for further evaluation. Five MoAbs, which recognized surface antigens expressed on parental B16 cells and the B16-F1, B16-F10, B16-F10 FLR, and B16-BL6 sublines, did not appear to cross-react with each other, suggesting that they identified antigenically distinct epitopes. Four MoAbs, designated as IB16-2, IB16-4, IB16-8, and IB16-10, recognized B16 surface antigens that were variably expressed over short periods of time. This variable expression was independent of the cell cycle and was characteristic of four B16 sublines. Two of these MoAbs, both of the IgG2b isotype, fixed rabbit and guinea pig complement and were cytolytic in the presence of rabbit complement. One MoAb, designated IB16-6, recognized a surface antigen consistently expressed on greater than 90% of cells of both the parental tumor and the sublines. This MoAb bound to several murine and one human melanoma cell line, but not to other histopathological types of tumors or normal tissues. The cellular antigen that this antibody recognized was not detected in the cytoplasm, did not modulate in the presence of IB16-6, and was sensitive to trypsin, pronase, alcohols, acetone, and detergents, thereby suggesting that it was a protein. Our data are among the first that directly show the extent of phenotypic diversity of the B16 melanoma and sublines that have been derived from it.

Animals↗

PubMed1987

Improved clinical approach to the diagnosis of canine ehrlichiosis.

Canine ehrlichiosis is being recognised with increasing frequency in many parts of the world. Based upon a detailed clinical and laboratory examination including a simple in vitro blood culture diagnostic test 373 cases have been classified into seven broad groups. These groups include acute, haemorrhagic, chronic, uraemic, subclinical, carrier state and those with babesiosis. While many of these groups overlap they will assist the clinician in diagnosis and allow the application of specific therapy before the disease progresses to a chronic irreversible stage.

Acute Disease↗