Differences in behavior and prognosis between leukemic and lymphomatous forms of a transplantable hamster lymphocytic neoplasm induced by simian virus 40.

Diamandopoulos, George Th.

doi:10.1073/pnas.75.4.2011

Cited by 5 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Histopathologists are well aware of the importance of the host's reaction to the tumour, but we have little information on how the direct contact of tumour cells with surrounding normal cells influences the growth of the tumour. For example, Diamandopoulos has presented evidence that the 'tissue environment that neoplastic lymphocytes encounter during circulation and/or proliferation regulates their subsequent behaviour in the intact host (Diamandopoulos 1978). I think it is also a good possibility that interferon influences this interaction of tumour with the stroma.…”

Section: T Able 2 D Ifferent Manifestations Of Interferon Action On Cells That May Affect Their Behaviourmentioning

confidence: 99%

How does interferon inhibit tumour growth?

1982

Phil. Trans. R. Soc. Lond. B

View full text Add to dashboard Cite

Interferon can inhibit tumour growth in experimental animals and in some patients with benign and malignant tumours. There is experimental evidence to suggest that several mechanisms may be involved: a direct effect on the tumor or an indirect effect via the host, or both. Thus, interferon may slow the rate of tumour cell multiplication and this may lead to cell death. Interferon may induce changes in the cell surface rendering tumour cells more sensitive to host defence mechanisms. Interferon may induce reversion in the phenotype of tumour cells. Interferon may stimulate specific and non-specific humoral and cellular host mechanisms. The relative importance of these different effects of interferon may vary depending on the host and the particular tumour.

show abstract

Section: T Able 2 D Ifferent Manifestations Of Interferon Action On Cells That May Affect Their Behaviourmentioning

confidence: 99%

How does interferon inhibit tumour growth?

1982

Phil. Trans. R. Soc. Lond. B

View full text Add to dashboard Cite

show abstract

“…Even in vivo, there are a number of examples of reversion or modulation of the tumorigenic potential of malignant cells depending on the site of implantation (Diamandopoulos, 1978;Revilla el al., 1978). For example, Diamandopoulos (1 978) has presented evidence that the "tissue environment that neoplastic lymphocytes encounter during circulation and/or proliferation regulates their subsequent behavior in the intact host".…”

Section: Phenotypic Behavior Of Transformed Cells When Seeded On Cellmentioning

confidence: 99%

Reversion of the transformed phenotype to the parental phenotype by subcultivation of X‐ray‐transformed C3H/10T1/2 cells at low cell density

Brouty‐Boyé

Baldwin

1979

Intl Journal of Cancer

View full text Add to dashboard Cite

Transformed cells induced by X-irradiation of a stable contact-inhibited line of C3H mouse embryo cells (10TZ) display an altered morphology (fibroblastic), a decreased sensitivity t o contact inhibition, a high cell saturation density, a decreased sensitivity t o interferon and a capacity t o form colonies i n agar and malignant tumors i n mice. Under certain experimental conditions, serial passage of transformed cells (from cloned lines) at low cell density (i.e., 400 cells per 25cmZ flask) was accompanied by a reversion from the transformed phenotype t o a phenotype characteristic of the parental untransformed 10TZ cells: epithelioid morphology, low cell saturation density, increased sensitivity t o interferon and failure t o form colonies i n agarose o r tumors i n mice. The revertent phenotype was stable as long as these cells were passed at low cell density. Passage a t high cell density, however, resulted i n a back reversion t o the transformed phenotype. When transformed cells were seeded at a much lower cell density, so that only a few colonies appeared per Petri dish, reversion t o the parental phenotype occurred at the first passage and appeared stable. Back reversion was no longer observed even when these cells were passed at high cell density. The experimental results suggested that reversion of the transformed t o the parental phenotype was not due t o a selection of a pre-existing population of cells with the parental phenotype but rather t o a change i n the phenotype of the entire cell population.Transformation of cells in vitro can occur "spontaneously" or after induction by viruses, chemical carcinogens or irradiation. Transformed cells can also be induced to lose some of the characteristics of the transformed state and revert to a more normal phenotype (Macpherson, 1965; Pollack et al., 1968; Rabinowitz and Sachs, 1968;Stephenson et al., 1973). We have recently observed that when transformed cells derived from X-irradiated cultures of mouse C3H/IOT1/2 cells were passaged at low cell density they assumed the morphologic phenotype of the parental cells. Investigation of this phenomenon showed that these "revertent" cells also displayed a number of other characteristics of the normal parental phenotype. Furthermore, when these cells were passaged at low cell density, the revertent phenotype remained stable and under certain conditions even appeared fixed, so that back reversion to the transformed state could no longer be induced by passage at high cell density. Since the means of inducing reversibility of the transformed state is of theoretical as well as of possible therapeutic interest, we present in some detail the results of these experiments. MATERIAL AND METHODS Cell culturesThe 10T% cell line, established from C3H mouse embryos (Reznikoff et al., 1973) was used between the 10th and 15th passages. The transformed X2 line was established by cloning a single type 111 focus (Brouty-Boye and Little, 1977) isolated from an X-irradiated culture of 10TX cells; and the transformed 5T, cell sublin...

show abstract

“…Numerous mechanisms can be put forward, which could include the secretion of soluble factors like hormones of interleukins, direct cell contact from other lymphoid or epithelial cells, basement membranes, and connective tissue stroma 1621. Regarding the question of leukemia vs. lymphoma, perhaps the most striking experiments were made by Diamandopou-10s [63,64]. This author obtained a transpIantabIe Iymphoid cell neoplasm in hamsters, caused by SV40.…”

Section: Heterogeneity Of T-rllmentioning

confidence: 99%