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[The binding characteristics of insulin-MTX to insulin receptor]
1Department of Nuclear Medicine, First Affiliated, Hospital WCUMS, Chengdu 610041, China.
Objective:
It has been reported that several kinds of tumors express increased insulin receptor and the molecules of insulin can be internalized in cells and may thence enter into the nuclei mediated by insulin receptor. In this study, we investigated the receptor binding characteristics of insulin-MTX for the possibility of using insulin as a carrier for carcinoma targeted therapy by receptor mediation.
Methods:
MTX(methotrexate) was covalently linked to insulin directly. The insulin-MTX conjugate was purified by polyacrylamine agarose gel electrophoresis and analysed by high performance liquid chromatography and SDS- polyacrylamine agarose gel electrophoresis. Histologically confirmed human hepatocellular carcinoma specimens were obtained from patients at surgery and immediately frozen under -80 degrees C. Cell membrane fractions were isolated by sucrose density gradient centrifugation. Competitive displacement of 125I-insulin with insulin and insulin-MTX binding to insulin receptor were carried out and the values of IC50 and Ki were calculated so as to observe the characteristics of insulin-MTX binding to insulin receptor.
Results:
Insulin-MTX competed as effectively as insulin with 125I-insulin for insulin receptor. The values of IC50 and Ki for insulin-MTX were 93.82 +/- 19.32 nmol/L and 91.88 +/- 16.86 nmol/L respectively, while the values of IC50 and Ki for insulin were 5.01 +/- 1.24 nmol/L and 4.85 +/- 1.12 nmol/L respectively.
Conclusion:
Insulin-MTX could bind with insulin receptor with high affinity. The result demonstrates us that there is a possibility of using insulin as a carrier for carcinoma targeted therapy by receptor mediation.
Insights
Researchers developed insulin-methotrexate (MTX) to target cancer cells. This conjugate binds to insulin receptors on tumors, showing potential for targeted drug delivery in carcinoma therapy.
Area of Science:
- Biochemistry
- Oncology
- Pharmacology
Context:
- Tumors often overexpress insulin receptors.
- Insulin can be internalized by cells and potentially reach the nucleus.
- This presents an opportunity for targeted drug delivery.
Purpose:
- To investigate the receptor binding characteristics of insulin-methotrexate (MTX).
- To assess the potential of using insulin as a carrier for receptor-mediated carcinoma targeted therapy.
Summary:
- Insulin was covalently linked to methotrexate (MTX) to create an insulin-MTX conjugate.
- The binding affinity of insulin-MTX to insulin receptors was evaluated using competitive displacement assays.
- Insulin-MTX demonstrated effective competition with 125I-insulin for insulin receptor binding.
Impact:
- Insulin-MTX exhibits high-affinity binding to insulin receptors.
- This finding supports the potential of insulin as a carrier for targeted cancer therapy.
- Further research may lead to novel strategies for treating hepatocellular carcinoma.