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Updated: May 31, 2026
A Convenient and General Expression Platform for the Production of Secreted Proteins from Human Cells
Published on: July 31, 2012
Expression, purification, refolding, and characterization of octreotide-interleukin-2: a chimeric tumor-targeting
Jing Jiang1, Leixiu Deng, Lichun He
1School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, PR China. jing_jiang1974@sina.com
Abstract:
The targeting of tumor cells by peptides for drug delivery is a promising strategy for cancer therapy. Interleukin-2 (IL-2), which mediates anti-tumor cellular immune responses, has been approved as a therapy for cancer. However, the serious side effects and short half-life of recombinant IL-2 (rIL-2) has limited its use clinically. Somatostatin receptors (SSTRs), which are expressed in a large number of human tumors, are the targets for in vivo tumor targeting. In this study, we have constructed and expressed a novel chimeric recombinant protein containing octreotide analogs and IL-2 in order to target the SSTR binding with tumor cells. The fusion protein somatostatin receptor targeted interleukin-2 (SIL), which was purified from bacterial inclusion bodies and refolded with high purity, was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. Tryptophan emission fluorescence was used to measure the structural changes in SIL after renaturation. Cell proliferation experiments showed that this chimeric protein retained the biological activities of hIL-2. Furthermore, the tumor binding capacity of SIL acting through SSTRs was shown through co-immunoprecipitation. Competition binding with octreotide of tumor cells also confirmed that SIL binds to tumor cells through the target peptide octreotide. Moreover, the performance of SIL in stimulating the proliferation of lymphocyte cell lines after binding to tumor cells showed that the immunocytokine, SIL, retained its bioactivity at the tumor site. These results suggest that SIL is a recombinant fusion protein that may be used for tumor-targeted drug delivery.
Insights
Researchers developed a novel fusion protein, somatostatin receptor targeted interleukin-2 (SIL), to improve cancer therapy. This targeted approach enhances drug delivery to tumors, potentially reducing side effects and increasing treatment efficacy.
Area of Science:
- Biotechnology
- Cancer Therapy
- Immunology
Background:
- Peptide-based tumor cell targeting is a promising strategy for cancer drug delivery.
- Recombinant interleukin-2 (rIL-2) shows anti-tumor immune responses but has clinical limitations due to side effects and short half-life.
- Somatostatin receptors (SSTRs) are overexpressed in many human tumors, making them ideal targets for in vivo tumor targeting.
Purpose of the Study:
- To construct and express a novel chimeric recombinant protein combining octreotide analogs and IL-2.
- To evaluate the tumor-targeting capability and retained biological activity of the fusion protein.
Main Methods:
- Construction and expression of the somatostatin receptor targeted interleukin-2 (SIL) fusion protein.
- Purification and refolding of SIL, followed by analysis using SDS-PAGE and RP-HPLC.
- Assessment of SIL's structural integrity, biological activity (cell proliferation), tumor binding capacity (co-immunoprecipitation), and specificity (competition binding).
Main Results:
- The purified SIL protein was successfully refolded and retained the biological activities of human IL-2.
- SIL demonstrated tumor binding capacity via SSTRs and confirmed binding specificity through octreotide competition assays.
- The immunocytokine SIL maintained bioactivity at the tumor site, stimulating lymphocyte proliferation after tumor cell binding.
Conclusions:
- SIL is a novel recombinant fusion protein with potential for targeted cancer drug delivery.
- The fusion protein effectively targets SSTR-expressing tumors and retains IL-2's immunomodulatory functions.
- SIL offers a promising strategy to enhance the efficacy and safety of IL-2-based cancer therapies.
