Surface-expressed insulin receptors as well as IGF-I receptors both contribute to the mitogenic effects of human insulin and its analogues
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Surface-expressed insulin receptors as well as IGF-I receptors both contribute to the mitogenic effects of human insulin and its analogues. / Lundby, Anders; Bolvig, Pernille; Hegelund, Anne Charlotte; Hansen, Bo F; Worm, Jesper; Lützen, Anne; Billestrup, Nils; Bonnesen, Christine; Oleksiewicz, Martin B.
In: Journal of Applied Toxicology, Vol. 35, No. 7, 07.2015, p. 842-850.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Surface-expressed insulin receptors as well as IGF-I receptors both contribute to the mitogenic effects of human insulin and its analogues
AU - Lundby, Anders
AU - Bolvig, Pernille
AU - Hegelund, Anne Charlotte
AU - Hansen, Bo F
AU - Worm, Jesper
AU - Lützen, Anne
AU - Billestrup, Nils
AU - Bonnesen, Christine
AU - Oleksiewicz, Martin B
N1 - Copyright © 2014 John Wiley & Sons, Ltd.
PY - 2015/7
Y1 - 2015/7
N2 - There is a medical need for new insulin analogues. Yet, molecular alterations to the insulin molecule can theoretically result in analogues with carcinogenic effects. Preclinical carcinogenicity risk assessment for insulin analogues rests to a large extent on mitogenicity assays in cell lines. We therefore optimized mitogenicity assay conditions for a panel of five cell lines. All cell lines expressed insulin receptors (IR), IGF-I receptors (IGF-IR) and hybrid receptors, and in all cell lines, insulin as well as the comparator compounds X10 and IGF-I caused phosphorylation of the IR as well as IGF-IR. Insulin exhibited mitogenicity EC50 values in the single-digit nanomolar to picomolar range. We observed correlations across cell types between (i) mitogenic potency of insulin and IGF-IR/IR ratio, (ii) Akt phosphorylation and mitogenic potency and (iii) Akt phosphorylation and IR phosphorylation. Using siRNA-mediated knockdown of IR and IGF-IR, we observed that in HCT 116 cells the IR appeared dominant in driving the mitogenic response to insulin, whereas in MCF7 cells the IGF-IR appeared dominant in driving the mitogenic response to insulin. Together, our results show that the IR as well as IGF-IR may contribute to the mitogenic potency of insulin. While insulin was a more potent mitogen than IGF-I in cells expressing more IR than IGF-IR, the hyper-mitogenic insulin analogue X10 was a more potent mitogen than insulin across all cell types, supporting that the hyper-mitogenic effect of X10 involves the IR as well as the IGF-IR. These results are relevant for preclinical safety assessment of developmental insulin analogues. Copyright © 2014 John Wiley & Sons, Ltd.
AB - There is a medical need for new insulin analogues. Yet, molecular alterations to the insulin molecule can theoretically result in analogues with carcinogenic effects. Preclinical carcinogenicity risk assessment for insulin analogues rests to a large extent on mitogenicity assays in cell lines. We therefore optimized mitogenicity assay conditions for a panel of five cell lines. All cell lines expressed insulin receptors (IR), IGF-I receptors (IGF-IR) and hybrid receptors, and in all cell lines, insulin as well as the comparator compounds X10 and IGF-I caused phosphorylation of the IR as well as IGF-IR. Insulin exhibited mitogenicity EC50 values in the single-digit nanomolar to picomolar range. We observed correlations across cell types between (i) mitogenic potency of insulin and IGF-IR/IR ratio, (ii) Akt phosphorylation and mitogenic potency and (iii) Akt phosphorylation and IR phosphorylation. Using siRNA-mediated knockdown of IR and IGF-IR, we observed that in HCT 116 cells the IR appeared dominant in driving the mitogenic response to insulin, whereas in MCF7 cells the IGF-IR appeared dominant in driving the mitogenic response to insulin. Together, our results show that the IR as well as IGF-IR may contribute to the mitogenic potency of insulin. While insulin was a more potent mitogen than IGF-I in cells expressing more IR than IGF-IR, the hyper-mitogenic insulin analogue X10 was a more potent mitogen than insulin across all cell types, supporting that the hyper-mitogenic effect of X10 involves the IR as well as the IGF-IR. These results are relevant for preclinical safety assessment of developmental insulin analogues. Copyright © 2014 John Wiley & Sons, Ltd.
U2 - 10.1002/jat.3082
DO - 10.1002/jat.3082
M3 - Journal article
C2 - 25413577
VL - 35
SP - 842
EP - 850
JO - Journal of Applied Toxicology
JF - Journal of Applied Toxicology
SN - 0260-437X
IS - 7
ER -
ID: 162900116