1α,25-Dihydroxyvitamin D3
 and its analogues, EB1089 and CB1093, profoundly inhibit the in vitro
 proliferation of the human hepatoblastoma cell line HepG2

Production of immuno and biologically active erythropoietin was documented to occur in the human hepatoblastoma cell line HepG-2. The expression of the erythropoietin gene was further verified by Northern blot analysis using a single stranded RNA probe. In vitro studies showed that erythropoietin production by these cells was not stimulated by hypoxia or cobalt chloride, but was related to the proliferative activity of the cells in culture. In addition it was found that the secretion of erythropoietin was almost completely abrogated by tunicamycin, an inhibitor of N-linked glycosylation. This effect of tunicamycin was also observed in a permanently transfected cell line that secretes erythropoietin in large quantities.

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Antibodies to Transcobalamin II Block In Vitro Proliferation of Leukemic Cells

Blood ◽

10.1182/blood.v89.1.235 ◽

1997 ◽

Vol 89 (1) ◽

pp. 235-242 ◽

Cited By ~ 20

Author(s):

Gary R. McLean ◽

Edward V. Quadros ◽

Sheldon P. Rothenberg ◽

A. Charles Morgan ◽

John W. Schrader ◽

...

Keyword(s):

Cell Growth ◽

Cell Line ◽

Megaloblastic Anemia ◽

Cell Surface Receptor ◽

Leukemic Cells ◽

Dependent Manner ◽

In Vitro Proliferation ◽

Congenital Deficiency ◽

Transcobalamin Ii

Abstract The plasma protein transcobalamin II (TCII) binds and delivers cobalamin (Cbl; vitamin B12) to all cells, which internalize the TCII/Cbl complex by receptor-mediated endocytosis. Congenital deficiency of TCII results in intracellular Cbl deficiency, one effect of which is to disrupt DNA synthesis, leading to megaloblastic anemia. We report here an in vitro culture system in which cell growth is dependent on delivery of Cbl to cells by TCII. Recombinant human holo-TCII was shown to support in dose-dependent manner the growth of the human erythroleukemic cell line K562 and the murine lymphoma cell line BW5147. Free Cbl also supported cell growth; however, at 100- to 1,000-fold higher concentrations than those effective in the presence of apo-TCII. To determine if cellular depletion of Cbl could be achieved by interfering with interactions between TCII/Cbl and its cell-surface receptor, several monoclonal antibodies raised against human TCII were studied. Three antibodies, found to compete for the same binding site on TCII, proved to be effective inhibitors of TCII/Cbl-dependent cell growth. Our results suggest that monoclonal anti-TCII antibodies that block the function of this protein may prove useful in antitumor therapies.

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The Effect of Different Agars, Agaroses and Methyl Cellulose on the in Vitro Proliferation of a Human Urinary Transitional Cell Carcinoma Cell Line

The Journal of Urology ◽

10.1016/s0022-5347(17)52670-1 ◽

1983 ◽

Vol 129 (6) ◽

pp. 1254-1257 ◽

Cited By ~ 3

Author(s):

Edward J. Pavlik ◽

Robert C. Flanigan ◽

John R. Van Nagell ◽

Linda Swanson ◽

Kathryn Keaton ◽

...

Keyword(s):

Transitional Cell Carcinoma ◽

Cell Carcinoma ◽

Cell Line ◽

Carcinoma Cell ◽

Transitional Cell ◽

Methyl Cellulose ◽

Carcinoma Cell Line ◽

In Vitro Proliferation

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Regulation of erythropoietin production in a human hepatoblastoma cell line

Blood ◽

10.1182/blood.v70.6.1904.1904 ◽

1987 ◽

Vol 70 (6) ◽

pp. 1904-1909 ◽

Cited By ~ 37

Author(s):

OJ Nielsen ◽

SJ Schuster ◽

R Kaufman ◽

AJ Erslev ◽

J Caro

Keyword(s):

Cell Line ◽

Northern Blot ◽

Proliferative Activity ◽

Northern Blot Analysis ◽

Cobalt Chloride ◽

Biologically Active ◽

Erythropoietin Production ◽

Rna Probe ◽

Hepatoblastoma Cell Line

Abstract Production of immuno and biologically active erythropoietin was documented to occur in the human hepatoblastoma cell line HepG-2. The expression of the erythropoietin gene was further verified by Northern blot analysis using a single stranded RNA probe. In vitro studies showed that erythropoietin production by these cells was not stimulated by hypoxia or cobalt chloride, but was related to the proliferative activity of the cells in culture. In addition it was found that the secretion of erythropoietin was almost completely abrogated by tunicamycin, an inhibitor of N-linked glycosylation. This effect of tunicamycin was also observed in a permanently transfected cell line that secretes erythropoietin in large quantities.

Download Full-text

Antibodies to Transcobalamin II Block In Vitro Proliferation of Leukemic Cells

Blood ◽

10.1182/blood.v89.1.235.235_235_242 ◽

1997 ◽

Vol 89 (1) ◽

pp. 235-242

Author(s):

Gary R. McLean ◽

Edward V. Quadros ◽

Sheldon P. Rothenberg ◽

A. Charles Morgan ◽

John W. Schrader ◽

...

Keyword(s):

Cell Growth ◽

Cell Line ◽

Megaloblastic Anemia ◽

Cell Surface Receptor ◽

Leukemic Cells ◽

Dependent Manner ◽

In Vitro Proliferation ◽

Congenital Deficiency ◽

Transcobalamin Ii

The plasma protein transcobalamin II (TCII) binds and delivers cobalamin (Cbl; vitamin B12) to all cells, which internalize the TCII/Cbl complex by receptor-mediated endocytosis. Congenital deficiency of TCII results in intracellular Cbl deficiency, one effect of which is to disrupt DNA synthesis, leading to megaloblastic anemia. We report here an in vitro culture system in which cell growth is dependent on delivery of Cbl to cells by TCII. Recombinant human holo-TCII was shown to support in dose-dependent manner the growth of the human erythroleukemic cell line K562 and the murine lymphoma cell line BW5147. Free Cbl also supported cell growth; however, at 100- to 1,000-fold higher concentrations than those effective in the presence of apo-TCII. To determine if cellular depletion of Cbl could be achieved by interfering with interactions between TCII/Cbl and its cell-surface receptor, several monoclonal antibodies raised against human TCII were studied. Three antibodies, found to compete for the same binding site on TCII, proved to be effective inhibitors of TCII/Cbl-dependent cell growth. Our results suggest that monoclonal anti-TCII antibodies that block the function of this protein may prove useful in antitumor therapies.

Download Full-text