RGD-modified streptavidin selectively binds to and inhibits growth of cancer cellsтезисы доклада Тезисы

Дата последнего поиска статьи во внешних источниках: 6 февраля 2017 г.

Работа с тезисами доклада

[1] Rubtsov M. A., Syrkina M. S., Veiko V. P. Rgd-modified streptavidin selectively binds to and inhibits growth of cancer cells // FEBS Journal Special Issue: FEBS EMBO 2014 Conference. — Vol. 281 of 281(suppl. 1). — Blackwell Publishing Inc United Kingdom, 2014. — P. 501–501. Nowadays the important role of cell adhesion molecules in invasion of metastatic tumor in surrounding tissues as well as in the growth of tumor blood vessels is well known. In particular the increased invasiveness and metastasizing that is typical for vertically growing melanoma is known to be mediated by specific integrins. So, integrin avb3 which is overexpressed in melanoma cells with high metastatic potential as well as in endothelial cells of tumor blood vessels and exhibits low expression level in normal melanocytes used to be an attractive target for melanoma diagnostics and therapy. Integrin avb3 is known to recognize the RGD peptide sequence which has been found in a wide variety of its natural ligands. A number of expression vectors analogous to constructs described in [1, 2] has been constructed. These vectors provide the production of the streptavidin fused with RGD-bearing peptides (SR10, SR13, SR15) in E.coli. These proteins were demonstrated to bind selectively to murine (B16F10) and human (MeWo) melanoma cells as well as to endothelial cells (HUVEC). In order to estimate kinetics of binding of each protein with receptors on the MeWo and HUVEC cell surface we’ve analyzed fluorescence intensity of cell population after incubation with FITC-labeled proteins SR10, SR13, SR15. We noted a characteristic feature – sharp decline in fluorescence intensity after 45 minutes of incubation. Probably this effect is due to the internalization of integrin receptors bound with SR10, SR13 or SR15. Internalization was confirmed by confocal fluorescent imaging of fixed MeWo and HUVEC cells. Luminous spots were detected on the membrane and in the compartment which is typical for endosome location. Moreover, it was noted that increase in incubation time leads to increase in fluorescence intensity both on the cell surface and in cytoplasm. Internalization observed might be caused by activation of the integrin receptors after binding with ligand. It’s known that activated receptors undergo endocytosis with the following recycling [3]. An influence of different concentrations of SR proteins on cell viability was estimated by XTT-test. It was demonstrated that incubation of HUVEC in the presence of 1.5 lM SR15 leads to two-fold decrease in cell proliferation rate. The maximum decrease in MeWo proliferation rate (up to 18%) was achieved by exposition of cells to SR13 in 0.075 lM concentration.

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