TY - JOUR
T1 - Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on insulin-induced responses in MCF-7 human breast cancer cells
AU - Liu, Hong
AU - Safe, Stephen
PY - 1996/6
Y1 - 1996/6
N2 - Insulin stimulated proliferation of MCF-7 human breast cancer cells in serum-free medium, whereas 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) did not affect cell growth. In cells cotreated with insulin plus TCDD or TCDF, insulin-induced cell proliferation and [3H]thymidine incorporation were inhibited. In contrast, α-naphthoflavone, a partial aryl hydrocarbon (Ah) receptor antagonist, blocked the inhibitory effects of TCDD, suggesting that the Ah receptor was involved in TCDD-induced responses in MCF-7 cells. TCDD alone did not affect K(d) and B(max) values for binding of [125I]insulin to the insulin receptor (IR); however, in MCF-7 cells cotreated with insulin plus TCDD, the insulin-induced K(d) value for IR-ligand binding was decreased and the B,, value was increased. TCDD induced IR mRNA levels and inhibited several other insulin-induced responses including c-fos protooncogene expression, phosphorylation of the insulin receptor, and a 185-kDa protein in MCF-7 cells.
AB - Insulin stimulated proliferation of MCF-7 human breast cancer cells in serum-free medium, whereas 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) did not affect cell growth. In cells cotreated with insulin plus TCDD or TCDF, insulin-induced cell proliferation and [3H]thymidine incorporation were inhibited. In contrast, α-naphthoflavone, a partial aryl hydrocarbon (Ah) receptor antagonist, blocked the inhibitory effects of TCDD, suggesting that the Ah receptor was involved in TCDD-induced responses in MCF-7 cells. TCDD alone did not affect K(d) and B(max) values for binding of [125I]insulin to the insulin receptor (IR); however, in MCF-7 cells cotreated with insulin plus TCDD, the insulin-induced K(d) value for IR-ligand binding was decreased and the B,, value was increased. TCDD induced IR mRNA levels and inhibited several other insulin-induced responses including c-fos protooncogene expression, phosphorylation of the insulin receptor, and a 185-kDa protein in MCF-7 cells.
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U2 - 10.1006/taap.1996.0122
DO - 10.1006/taap.1996.0122
M3 - Article
C2 - 8658525
AN - SCOPUS:0030175873
VL - 138
SP - 242
EP - 250
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
SN - 0041-008X
IS - 2
ER -