Membrane alterations associated with “transformation” by BUdR in BUdR-dependent cells

Rosenthal, S; Parola, Abraham H.; Blout, E. R.; Davidson, Richard L.

doi:10.1016/0014-4827(78)90224-0

Cited by 19 publications

(12 citation statements)

References 14 publications

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“…Our results with the present tumorigenic system are in agreement with those previously reported for the transformed non-tumorigenic cell lines (Fuchs et al, 1975;Rosenthal et a[., 1978) in terms of the direction in change of p with transformation and reversion. Other independent studies showed similar trends in membrane fluidity (Edwards et a/., 1976;Yau et a/., 1976).…”

Section: Discussionsupporting

confidence: 94%

“…This conclusion is based on estimation of the change in the probe's lifetime from changes in its relative fluorescence intensities (Shinitzky and Inbar, 1974). The change in lifetime as a function of temperature is an order of magnitude (percentage-wise) smaller than the corresponding change in p (Rosenthal et al, 1978). The plots shown in Figure 2 demonstrate that there is no phase transition in the lipid bilayers at the temperature range studied, as there are no breaks in the lines.…”

Section: Fhorescence Studiesmentioning

confidence: 94%

“…p values at different temperatures were obtained according to our previously described procedure (Fuchs et al, 1975;Rosenthal et al, 1978). Measurements of uniform cell suspensions (verified by microscopy) were carried out on a MPF-44 Perkin Elmer spectrofluorometer.…”

Section: Fluorescence Polarization Measurementsmentioning

confidence: 99%

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Membrane dynamic alteration associated with the tumorigenicity of polyoma‐transformed and revertant hamster cells

Parola¹,

Souroujon²

1979

Intl Journal of Cancer

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Steady state fluorescence polarization studies were carried out on membranes of polyoma-virus-transformed, revertants, re-revertants, and normal golden hamster cells. Four clones of revertant cells which exhibit different levels of reversion were isolated. The degree of reversion in these revertant clones was characterized in vitro by their contact inhibition behavior and in vivo by their tumorigenicity to hamsters. A good correlation between these two criteria was observed. Re-revertant cells were obtained from that revertant clone which exhibited the highest degree of reversion (similar to normal cells) and which could still produce tumors in hamsters. Re-revertants resembled the polyomavirus-transformed cells in both contact inhibition and tumorigenicity. Fluorescence polarization values of 1.6-diphenyl-1,3,5-hexatriene-labelled cells correlated well with cell tumorigenicity: normal and revertant cells which were not malignant exhibited distinctly lower fluorescence polarization values than those of the tumorigenic transformed and re-revertant cells. Intermediary revertant clones exhibited fluorescence polarization values in between those of normal and transformed cells, yet indistinguishable within experimental uncertainty.

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Section: Discussionsupporting

confidence: 94%

Section: Fhorescence Studiesmentioning

confidence: 94%

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Membrane dynamic alteration associated with the tumorigenicity of polyoma‐transformed and revertant hamster cells

Parola¹,

Souroujon²

1979

Intl Journal of Cancer

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“…Similar effects on the precursor pool have also been observed in sea urchin embryos (33). Such a phenomenon is probably related to the finding that the surface membrane is drastically affected by BrdU in melanoma cells (19) and in other cells (34).…”

Section: Discussionsupporting

confidence: 72%

“…Silagi and Bruce (6) reported that BrdU inhibited melanogenesis in B16 mouse melanoma cells and that the effect was specific for melanogenesis, since the viability of the cells was little affected. Some other aspects of BrdU effect on melanoma cells (the reduction of tyrosinase activity, the decrease in tumorigenecity, differential effect~on mRNA population, and membrane alteration) have also been identified (15)(16)(17)(18)(19). In the present study, we examined the effects of BrdU on the growth as well as on enzyme activities in B16 melanoma cells.…”

Section: Introductionmentioning

confidence: 90%

Differential Effects of 5‐bromodeoxyuridine on B16 Mouse Melanoma Cells

Sugita

Takeuchi

1982

The Journal of Dermatology

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The effects of 5-bromodeoxyuridine (BrdU) on BI6 mouse melanoma were studied and the following results were obtained. 1) Melanogenesis of cells was completely inhibited by BrdU.2) Tyrosinase activity was reduced linearly with time by BrdU, but cytochrome c oxidase was not affected.3) The polysome profile from controls and that from BrdU-treated cells resembled each other when assayed at 260nm. However, the radioactivity in polysomes in the treated cells was about 30-40% ofthat in the control, when pulse labeled with radioactive uridine. 4) Polysomal RNAs were fractionated into poly(A)-containing and non-poly(A)-containing RNA with the use of poly(U)-Sepharose, and both types of RNA were examined by polyacrylamide gel electrophoresis. No significant differences were detected between the control and the BrdUtreated cells in either type of RNA.5) The effects of BrdU are specific for melanogenesis and the differences in polysomal RNAs might be too small to detect in our experiments. Immunoprecipitation of mRNAs for melanosomal proteins will be necessary to detect persuasive differences.

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Chicken embryo fibroblasts exposed to weak, time‐varying magnetic fields share cell proliferation, adenosine deaminase activity, and membrane characteristics of transformed cells

Parola

Porat

Kiesow

1993

Bioelectromagnetics

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Chicken embryo fibroblasts (CEF) exposed to a sinusoidally varying magnetic field (SVMF) (100 Hz, 700 microT, for 24 h) showed a remarkable rise of segmental rotational relaxation rate of adenosine deaminase (ADA, EC 3.5.4.4) as determined by multifrequency phase fluorometry. Pyrene-labeled, small subunit ADA was applied to cultured (normal) CEF, which have available and abundant ADA complexing protein (ADCP) on their plasma membranes. Sine-wave-modulated fluorometry of the pyrene yielded a profile of phase angle vs. modulation frequency. In SVMF-treated cells and in Rous-sarcoma-virus (RSV) transformed cells the differential phase values at low modulation frequencies of the excitation are remarkably reduced. This effect is magnetic rather than thermal, because the temperature was carefully controlled and monitored; nevertheless to further check this matter we studied CEF, infected by the RSV-Ts68 temperature-sensitive mutant (36 degrees C transformed, 41 degrees C "revertant"). When grown at 36 degrees C in the SVMF, cells did not show the slightest trend towards reversion, as would be expected had there been local heating. Concomitant with the increased segmental rotational relaxation rate of ADA, there was a decrease in fluorescence lifetime and a slight, yet significant, increase in membrane lipid "microfluidity." These biophysical observations prompted us to examine the effect of SVMF on cell proliferation and ADA activity (a malignancy marker): higher rates of cell proliferation and reduced specific activity of ADA were observed.

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Membrane alterations associated with “transformation” by BUdR in BUdR-dependent cells

Cited by 19 publications

References 14 publications

Membrane dynamic alteration associated with the tumorigenicity of polyoma‐transformed and revertant hamster cells

Membrane dynamic alteration associated with the tumorigenicity of polyoma‐transformed and revertant hamster cells

Differential Effects of 5‐bromodeoxyuridine on B16 Mouse Melanoma Cells

Chicken embryo fibroblasts exposed to weak, time‐varying magnetic fields share cell proliferation, adenosine deaminase activity, and membrane characteristics of transformed cells

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