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D Tarin

Publications and source records attributed to D Tarin.

At least 55 records · Page 3Linked to original sources
PubMed1994

Cellular and hormonal mechanisms associated with malignant bone resorption.

BACKGROUND: To obtain a better understanding of the cellular and hormonal mechanisms responsible for the malignant bone resorption associated with metastatic carcinoma, we sought to identify whether tumor cells or tumor infiltrating macrophages were capable of lacunar bone resorption. EXPERIMENTAL DESIGN: Tumor cells and tumor-infiltrating macrophages (TIMS), (nonspecific esterase and F4/80 positive: cytokeratin and tartrate-resistant acid phosphatase and calcitonin response negative), were isolated from carcinomas that developed after subcutaneous implantation of human breast, colon, and cervical carcinoma cell lines into MFI athymic nude mice. These cells were cultured alone or with stromal cells on bone slices and evidence of lacunar resorption sought by scanning electron microscopy. RESULTS: After 7 to 14 days in co-culture with UMR106 osteoblast-like cells in the presence of 1,25-dihydroxy vitamin D3, only cells of the TIM population differentiated into osteoclast-like cells (nonspecific esterase-negative: tartrate-resistant acid phosphatase-positive) capable of extensive lacunar bone resorption. CONCLUSIONS: Cells within the TIM population but not tumor cells are capable of differentiation into osteoclast-like cells which can resorb bone extensively. Both 1,25 dihydroxyvitamin D3 and bone stromal cells are necessary for this to occur. TIM differentiation into cells capable of lacunar resorption could account for a component of the extensive osteolysis associated with carcinomatous skeletal metastases.

Adenocarcinoma↗
PubMed1993

Deranged activity of the CD44 gene and other loci as biomarkers for progression to metastatic malignancy.

About one in three people in modern industrialised countries die of the consequences of malignant tumours or are found to carry an unsuspected one at the time of autopsy. Early resection of such lesions and appropriate adjuvant therapy is very effective in curing the disease. There is therefore a strong clinical incentive to find effective methods of early diagnosis, assessment of prognosis and treatment of neoplastic lesions and research on this topic is directed at a numerically significant medical problem. Recently it has been found that many human tumours show severe abnormalities in the expression of the CD44 gene which increase with progression to metastatic malignancy. By alternative splicing mechanisms this gene codes for a family of heavily glycosylated cell surface proteins involved in many important cellular activities. In neoplasia there is gross overexpression of various products of the gene associated with disorderly splicing, which can be detected in clinical samples with the sensitive technique of reverse transcription-polymerase chain reaction (RT-PCR). These disturbances begin early in the neoplastic process and can be detected in very small biopsy samples. It has also been shown that it is possible to achieve non-invasive diagnosis of malignancy by analysis of CD44 expression in exfoliated cells in body fluids and waste products. The potential significance of these observations for early diagnosis of symptomatic cancer and for screening of the population for asymptomatic lesions are readily seen and await further investigation. Separate work in our laboratory has succeeded in DNA-mediated transfer of metastatic capability through two rounds of transfection into non-metastatic tumour cells and a metastasis-associated human DNA fragment has been recovered from the transfectants and sequenced. Using primers designed to anneal to a coding region identified by computer analysis within the novel sequence, it has been shown with RT-PCR that it is heavily expressed in metastatic cancer tissues, but not in corresponding normal ones. This could be of value in assessing the prognosis of patients using small biopsy samples from their primary tumours and the potential of this sequence for such purposes and for possible therapeutic intervention is currently being explored. Recent work in several laboratories has shown that elevated expression of certain other specific growth factor genes, including c-met and EGFR, correlates with metastatic capability. Combined evaluation of such markers in further studies will in time give useful information on the prognosis of individual patients to guide therapeutic decisions and the implications of these recent advances for clinical practice and future research are discussed below.

Animals↗
PubMed1993

Correlation of VLA-4 integrin expression with metastatic potential in various human tumour cell lines.

This investigation has focused on whether a number of molecular species, which have recently been recognised as components of cell attachment receptors utilised in recirculatory leukocyte traffic, are expressed on metastatic tumour cell populations. This has been studied on live cultured metastatic and non-metastatic tumour cell lines as well as on histological sections of frozen tissue from primary tumours and metastases which they formed after inoculation into nude mice. Here we report data we have obtained using immunofluorescence microscopy, fluorescence activated cell analysis, immunocytochemistry and pathological investigation of tumour behaviour in vivo, which converge to indicate that expression of the integrin molecule VLA-4 is positively associated with the execution of the metastatic process. This molecule is known to be a receptor for at least two ligands, namely the inducible endothelial adhesion molecule VCAM-1 and the extracellular matrix component fibronectin, and is thought to be mechanistically important in the attachment and diapodesis of lymphocytes. The present findings, indicating differential expression of this molecule on metastatic cell populations relative to non-metastatic cell populations, support and extend recent reports from other laboratories, of the presence of various leukocyte adhesion receptors on metastatic tumour cells. This accumulating evidence suggests that inappropriate expression of one or more of these surface adhesion molecules in tumour cell lineages may endow the progeny of the affected clones with some of the properties needed for metastatic behaviour. The total information so far assembled by various groups also provides some early clues suggesting that the types of molecules expressed may be related to the histogenetic origin of the tumour and its pattern of metastatic spread.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Transfection of metastatic capability with total genomic DNA from human and mouse metastatic tumour cell lines.

From a large series of experiments involving transfer of high molecular weight total genomic DNA from highly metastatic human and mouse tumour cell lines to other mouse tumour cell lines we have derived a few cell lines with greatly augmented metastatic properties. In one of these experiments the transfected cell line (designated AH8 Test) not only colonised the lungs but also formed secondary tumour colonies in several extrapulmonary sites including the skin, skeletal muscles, bone, liver diaphragm, spleen and heart. There were no qualitative and quantitative effects of this magnitude when we used DNA from several non-metastatic or non-tumourigenic sources. Secondary transfection of metastatic capability with DNA obtained from a metastasis formed by one of the primary transfectant lines (AH8 Test) has also been accomplished. Concomitant transfer of human DNA through both transfection cycles in this experiment was confirmed by a variety of methods including Southern blot analysis, in situ hybridisation and polymerase chain reaction (PCR) amplification of DNA using primers recognising human-specific Alu repeat sequences. The findings offer opportunities for the isolation of sequences programming metastatic behaviour and we have cloned and sequenced a fragment of human DNA, which has not been previously characterised, from the transfected cells.

Animals↗
PubMed1993

Studies on relationships between metastatic and non-metastatic tumor cell populations using lineages labeled with dominant selectable genetic markers.

The relationships between metastatic and non-metastatic cell populations co-existing in composite neoplasms have been studied using cell lineages marked with a dominant selectable marker (neomycin resistance), by transfection. The experimental circumstances were arranged so that the lineages were known to be genotypically distinct (i.e. not merely phenotypic variants of the same lineage) and so that a single metastatic clone was each time combined with a mixed polyclonal non-metastatic population and both partners were distinctly and recognizably marked. This made it possible to ascertain the fates of clones with different metastatic capabilities during tumor progression and metastasis and evaluate their relative contributions to the clinical extent of disease. It was found that metastatic and non-metastatic cell lineages co-existed in most of the late-stage primary tumors examined and that a cell lineage that is invariably non-metastatic, when growing on its own, can with surprising frequency be found thriving in distant metastatic deposits, when it grows to form a primary tumor in combination with a metastatic partner. In fact, occasional metastases from such tumors contained no detectable cells of the metastatic lineage. The endowment of a tumor cell lineage with a new, clinically significant, capability which it convincingly and reproducibly did not manifest before, by another coexisting cell population raises several new questions about the contribution of such phenomena to the overall debilitating properties of the neoplasm and the geometric progression of its impact on the host.

Animals↗
PubMed1992

Significance of CD44 gene products for cancer diagnosis and disease evaluation.

With increasing emphasis on the early detection of cancer, the search is on for reliable markers that will be clinically helpful in the diagnosis of small tumours and in the assessment of their metastatic potential. This report presents evidence that an abnormal pattern of activity of the CD44 gene is a promising candidate for both of these purposes in various types of malignancy. By a mechanism known as alternative splicing this gene can produce different messenger RNA molecules (transcripts) which are detectable, after amplification, as separate bands in electrophoretic gels. In neoplasia many abnormal variant transcripts are produced. A previous finding in animal experiments, that one such variant might be important in metastasis, prompted our study of human tumour tissue, benign and malignant, and of corresponding normal tissues. We studied tumour tissue from 34 patients with neoplastic disease (mostly breast or colon cancer) and normal or non-malignant diseased breast or colonic tissue from 11 patients and peripheral blood leucocytes from 4 healthy volunteers. CD44 gene activity was studied by amplifying messenger RNA with the polymerase chain reaction (PCR) followed by electrophoresis and blot hybridisation. In malignant tissues there was gross overproduction of each of 9 or more alternatively-spliced large molecular variants in all samples, whereas in the control samples only the standard product was routinely detected with occasional minimal quantities of one or two small variants. Furthermore, the band pattern permitted differentiation between the 23 cases with metastatic tumours of the breast or colon and the 8 with no detectable metastases. Calibration studies seeding blood with tumour cells showed that the technique can detect as few as 10 tumour cells among 10(7) leucocytes (1 ml of blood). Analysis of CD44 splice variants may prove to have applications not just to the early detection of metastatic potential in surgical biopsy specimens but also, if our findings are confirmed, in readily available bodily fluids, to the early diagnosis of cancer in screening programmes, to the assessment of remaining disease in the body and to the early detection of recurrences.

Adult↗
PubMed1992

DNA fingerprinting survey of various human tumors and their metastases.

DNA fingerprinting with the minisatellite probes 33.6 and 33.15 was used to screen for genetic abnormalities in primary tumors of a variety of organs and, where appropriate, their metastases, obtained from 32 patients. The constitutional DNA of each host, obtained from blood leukocytes or normal tissue, was used to produce control, individual-specific fingerprints for comparison with those of their tumor. Fingerprints obtained with probe 33.6 showed differences between tumor and host fingerprints in 69% of patients and those produced with 33.15 in 55%. The most common change was loss or reduction in the intensity of one or more bands, but the appearance of new bands, not present in the fingerprint of the constitutional DNA, was also noted in several tumor DNA samples. The findings are interpreted as indicating loss or rearrangement of expressed sequences in the chromosomal regions adjacent to the hypervariable tandem repeat intron arrays which are detected by these probes. In three patients further differences were identified between primary tumors and their metastatic deposits. With this technique it is possible to perform simultaneous multilocus screening of the genome and the present results show that it has potential for identification of as yet unknown abnormalities in DNA constitution, which may be of pathogenetic significance.

Autoradiography↗
PubMed1992

Fate of clonal lineages during neoplasia and metastasis studied with an incorporated genetic marker.

The fate of clonal lineages in tumor formation and metastasis has been studied by genotypic marking of cells from three separate tumor lines of different malignant potential. Marking was accomplished by random incorporation of the neomycin resistance gene and visualized by Southern blot analysis of integration sites. Primary tumors formed by polyclonal cell suspensions of all three cell lines injected s.c. usually remained polyclonal even at late stages of tumor growth and metastatic spread. Lung metastases were often clonal, but it was not unusual to find ones of polyclonal origin. Lymph node metastases were almost always polyclonal and remained so, as they grew large. Sometimes clones present in the original inoculum were absent in the primary. Other times clones visible in the metastases were undetectable in the corresponding primary tumor. Occasionally a single clone became dominant in the primary, and others were eliminated, but this was not a necessary prelude to the onset of invasive or metastatic behavior. It is concluded that there is considerable variation in the results obtained with various cell lines in different circumstances. Even clones which are underrepresented in the original inoculum or the primary tumor can acquire metastatic capability. Hence, progression of malignancy is not uniformly dependent on prior or concurrent extinction of other non- or less metastatic clones in the neoplasm, and the underlying mechanisms of invasion and metastasis can be separated from those which sometimes confer growth supremacy on a clone of tumor cells. The frequent continuing genetic heterogeneity of cells in a neoplasm has substantial implications for clinical treatment protocols.

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

The ras oncogene and tumour metastasis: observations on murine cells transfected with activated human c-Ha-ras.

Transfection of cells with cloned genes or total genomic DNA offers a means for studying aspects of neoplastic behaviour. We have used this method to examine whether incorporation of the cloned 6.6-kilobase (kb) fragment of DNA containing the mutant c-Ha-ras human oncogene can confer metastatic capability on murine NIH 3T3 cells. Cells co-transfected with the mutated ras gene and the neomycin resistance marker pSV2neo were selected by culture in neomycin. On subcutaneous inoculation into MF 1 nude mice, these cells proved to be tumourigenic with short latent periods (approximately 14 days)--nude mice were used to circumvent immunological rejection of the mouse cells expressing the product of the human oncogene. Transfectants were capable of lung colonisation after intravenous injection, but there was no evidence of spontaneous metastasis at autopsy, or on histological examination of the lungs and other organs, 90 days after inoculation. Incorporation of the transfected oncogene was confirmed by Southern blotting and its expression by dot-blot hybridisation and immunoprecipitation. The results in this experimental system indicate that transfection of a mutated human ras oncogene into non-neoplastic 3T3 cells can confer part of the metastatic phenotype, namely lung colonisation, but is not by itself sufficient to induce spontaneous metastatic behaviour.

Animals↗
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

Molecular genetics of metastasis.

We have adopted various approaches to identifying the genes(s) involved in metastasis. The first has been to observe whether introducing a defined activated oncogene (c-Ha-ras 1) into non-neoplastic cells confers not only tumorigenicity but other characteristics of malignancy. A second approach involves transfection of total genomic DNA from highly metastatic into nonmetastatic tumour cells. Thirdly, we are studying whether treatment of weakly metastatic tumour cells with agents known to influence tumour progression and gene expression (e.g. 12-O-tetradecanoylphorbol-13-acetate or 2'-deoxy-5-azacytidine) can affect metastatic capability. It was found that 3T3 fibroblasts which incorporated and expressed the activated rasH oncogene became tumorigenic and capable of lung colonization but not spontaneously metastatic. Additionally, transfection of inert tumour cells with DNA from highly metastatic human and animal cell lines sometimes markedly augmented their spontaneous metastatic capability and their lung colony-forming potential and induced them to form deposits in many extrapulmonary sites. Treatment of some tumour cell lines with azacytidine and 12-O-tetradecanoylphorbol-13-acetate markedly increased their metastatic behaviour after subcutaneous inoculation. Because several cell divisions occurred to produce the subcutaneous tumour before the cells disseminated, we consider the changed phenotype to be heritable and probably caused by alterations in gene expression. These results suggest that components of the metastatic phenotype are heritable and highly conserved in evolution and can be conferred on previously non-metastatic tumour cells by transfer of genomic DNA. In other studies we found that metastasizing tumour cells reach all organs in the body within minutes of entry into the blood but that the distribution of subsequent secondary tumours is neither uniform nor proportional to the numbers of cells retained in each site. The patterns of distribution of metastases tend to be related to the tissue of origin of the primary tumour. This was confirmed in observations on patients with intractable malignant ascites treated with peritoneo-venous shunts. Co-culture of tumour cells with fragments of various organs in vitro supported the conclusion that the normal cells of organs can support or inhibit secondary tumour formation. These observations collectively indicate that metastasis results from acquired abnormalities in gene regulation in tumour cells, but that the resulting abnormal cell behaviour can sometimes be modified or inhibited by local or systemic conditions in the host.

Animals↗
PubMed1988

Tumorigenic transformation of mouse NIH 3T3 cells by transfection with plasmid pSV2neo.

This study reports high incidence tumourigenic activity of the pSV2neo plasmid demonstrated by transfection of NIH 3T3 cells. The plasmid is frequently used as a dominant selectable marker for confirming successful gene transfection, and the findings indicate a need for caution in interpretation and design of assays for oncogenes which use co-transfection and subsequent selection with neomycin.

Animals↗
PubMed1987

Effect of pre-operative blood transfusion on tumour metastases.

The effects of allogenic blood transfusion on the subcutaneous growth and metastatic spread of two types of mouse tumour (B16 melanoma syngeneic to the C57/BL6 mouse and UV-2237 fibrosarcoma syngeneic to the C3H/He mouse) were studied. The growth rates of the primary tumour were not altered by transfusing the animals with allogeneic blood 14 days before tumour inoculation, but spontaneous metastasis from tumours formed at the inoculation site was augmented and accelerated for both tumour types. This effect was dependent on the strain of the blood donor, metastases of B16 melanoma being augmented by transfusion with blood from Balb/c animals, and UV-2237 fibrosarcoma by transfusion with C57/BL6 blood, but not by blood from other donor strains tested.

Animals↗
PubMed1987

Effects of altering surface glycoprotein composition on metastatic colonisation potential of murine mammary tumour cells.

This study has examined cells from naturally-occurring murine mammary tumours to ascertain whether cell surface glycoproteins play a significant role in colonisation of the lungs after intravenous inoculation. It was found that gel electrophoretic analysis of membrane extracts and lectin adsorption studies did not reveal any consistent differences in glycoprotein composition of cells from tumours which can heavily colonise the lungs relative to ones from tumours which cannot do so or to cells from pulmonary metastases. Also, alteration of structural and functional properties of surface glycoproteins by treatment with succinylated lectins or with drugs such as tunicamycin and swainsonine, which inhibit glycosylation of membrane proteins, had no specific effects on metastatic colonisation of the lungs. Tunicamycin apparently decreased capability to form experimental metastases but also diminished tumourigenicity on subcutaneous inoculation, although it did not affect tumour cell viability in vitro. This information supports earlier studies from this laboratory involving enzymic digestion of the surface of living tumour cells before inoculation and demonstrates that the pulmonary colonisation capability of these mammary tumour cells can withstand global disorganisation of membrane glycoprotein structure and composition. This implies that either the surface glycoproteins are not important in the colonisation process, or that these tumour cells have great capability for rapid repair of their surfaces. It is concluded that a clear answer to whether surface glycoprotein composition has a decisive role in pulmonary colonisation by these mammary tumour cells requires introduction of stable heritable traits into tumour cell populations by genetic manipulation.

Alkaloids↗