Abstract
Binding of [20-3H]phorbol 12,13-dibutyrate ([3H]PDB) to intact human promyelocytic leukemia cells susceptible (HL-60) or resistant (R-35) to phorbol ester-induced differentiation was characterized. Specific binding of [3H]PDB to both HL-60 and R-35 cells at 37°C reached a maximum within 15-20 min. Maximal specific [3H]PDB binding to HL-60 cells was followed by a decline (down regulation) of radioactivity. This down regulation was temperature dependent, because no loss of radiolabel occurred by 1 hr at 4°C. The down regulation of bound [3H]PDB seen in HL-60 cells at 37°C was not observed with R-35 cells. Prior exposure of the HL-60 cells but not of R-35 cells to 1 μM phorbol 12-myristate 13-acetate for 90 min at 37°C caused a marked reduction in the specific binding of [3H]PDB. When [3H]PDB binding was carried out at 4°C, [3H]PDB bound to both cell types in a rapid, specific, and reversible manner. At equilibrium, HL-60 and R-35 cells were found to contain almost the same number of binding sites, which had dissociation constants of about 50 nM, indicating that the failure of R-35 cells to undergo PDB-induced differentiation was not associated with any change in the affinity or in the number of [3H]PDB binding sites. These results indicate that the down regulation specific [3H]PDB binding may be a crucial early event in the control of phorbol ester-induced terminal differentiation in HL-60 cells. Furthermore, we suggest that such down regulation may be involved in other cellular and biochemical effects of phorbol diester tumor promoters.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1722-1725 |
| Number of pages | 4 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 78 |
| Issue number | 3 I |
| State | Published - 1981 |
| Externally published | Yes |
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- Genetics
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Down regulation of specific binding of [20-3H]phorbol 12,13-dibutyrate and phorbol ester-induced differentiation of human promyelocytic leukemia cells. / Solanki, V.; Slaga, Thomas J; Callaham, M.; Huberman, E.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 78, No. 3 I, 1981, p. 1722-1725.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Down regulation of specific binding of [20-3H]phorbol 12,13-dibutyrate and phorbol ester-induced differentiation of human promyelocytic leukemia cells
AU - Solanki, V.
AU - Slaga, Thomas J
AU - Callaham, M.
AU - Huberman, E.
PY - 1981
Y1 - 1981
N2 - Binding of [20-3H]phorbol 12,13-dibutyrate ([3H]PDB) to intact human promyelocytic leukemia cells susceptible (HL-60) or resistant (R-35) to phorbol ester-induced differentiation was characterized. Specific binding of [3H]PDB to both HL-60 and R-35 cells at 37°C reached a maximum within 15-20 min. Maximal specific [3H]PDB binding to HL-60 cells was followed by a decline (down regulation) of radioactivity. This down regulation was temperature dependent, because no loss of radiolabel occurred by 1 hr at 4°C. The down regulation of bound [3H]PDB seen in HL-60 cells at 37°C was not observed with R-35 cells. Prior exposure of the HL-60 cells but not of R-35 cells to 1 μM phorbol 12-myristate 13-acetate for 90 min at 37°C caused a marked reduction in the specific binding of [3H]PDB. When [3H]PDB binding was carried out at 4°C, [3H]PDB bound to both cell types in a rapid, specific, and reversible manner. At equilibrium, HL-60 and R-35 cells were found to contain almost the same number of binding sites, which had dissociation constants of about 50 nM, indicating that the failure of R-35 cells to undergo PDB-induced differentiation was not associated with any change in the affinity or in the number of [3H]PDB binding sites. These results indicate that the down regulation specific [3H]PDB binding may be a crucial early event in the control of phorbol ester-induced terminal differentiation in HL-60 cells. Furthermore, we suggest that such down regulation may be involved in other cellular and biochemical effects of phorbol diester tumor promoters.
AB - Binding of [20-3H]phorbol 12,13-dibutyrate ([3H]PDB) to intact human promyelocytic leukemia cells susceptible (HL-60) or resistant (R-35) to phorbol ester-induced differentiation was characterized. Specific binding of [3H]PDB to both HL-60 and R-35 cells at 37°C reached a maximum within 15-20 min. Maximal specific [3H]PDB binding to HL-60 cells was followed by a decline (down regulation) of radioactivity. This down regulation was temperature dependent, because no loss of radiolabel occurred by 1 hr at 4°C. The down regulation of bound [3H]PDB seen in HL-60 cells at 37°C was not observed with R-35 cells. Prior exposure of the HL-60 cells but not of R-35 cells to 1 μM phorbol 12-myristate 13-acetate for 90 min at 37°C caused a marked reduction in the specific binding of [3H]PDB. When [3H]PDB binding was carried out at 4°C, [3H]PDB bound to both cell types in a rapid, specific, and reversible manner. At equilibrium, HL-60 and R-35 cells were found to contain almost the same number of binding sites, which had dissociation constants of about 50 nM, indicating that the failure of R-35 cells to undergo PDB-induced differentiation was not associated with any change in the affinity or in the number of [3H]PDB binding sites. These results indicate that the down regulation specific [3H]PDB binding may be a crucial early event in the control of phorbol ester-induced terminal differentiation in HL-60 cells. Furthermore, we suggest that such down regulation may be involved in other cellular and biochemical effects of phorbol diester tumor promoters.
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M3 - Article
C2 - 6940185
AN - SCOPUS:0007714953
VL - 78
SP - 1722
EP - 1725
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 3 I
ER -