The Impact And Mechanism Of Gold Nanoparticles Conjugated With Dual-target Inhibitors On The Radiosensitivity Of Triple-negative Breast Cancer Cell

Background and purpose Triple negative breast cancer(TNBC) are defined as tumors that are negative for ER, progesterone receptor and HER 2, which is a subtype characterized by its particular molecular profile and aggressive biological behavior. Multiple targets exist and play an important role in the radiosensitivity regulation of TNBC.Strategies to improve radiosensitivity therefore to increase the efficacy of treatment has been a hot spot in translational radiotherapy research. In our study, we designed and constructed multifunctional gold nanoparticles conjugated with dual target inhibitors(RGD and TKI 258) as desensitizing agent(TKI 258 p GNRs@m Si O2 RGD), aiming at observing their impact on radiosensitivity of TNBC MDA MB 231 cell line and explore the mechanism.Methods and Materials In our study, we designed and developed GNRs@m Si O2 nanomaterials conjugated with dual target inhibitors(RGD and TKI 258) as radiotherapy sensitizing agents and tumor targeted drug delivery system. The multifunctional nanorods were incubated by MDA MB 231 cell line and MCF 7 cell line, cell proliferation and cytotoxicity grading were detected by the MTT method and cell counting kit 8(CCK 8)method. The ransmission electron microscope was used to detect the gold nonarods in cells. MDA MB 231 cell incubated with gold nanorods has been irradiated by clinical electron beams(6 Me V). The radiosensitizing effect was detected by clonogenic assay. The cell cycle, apoptosis and?v?3 expression level was examined by flow cytometry(FCM). The VEGFR expression was determined by West blot assay.Results 1. GNRs were synthesized by the seed mediated method and coated with mesoporous silica by surface modify. The integrin ? v ? 3 and vascular endothelial growth factor receptor(VEGFR) inhibitors RGD and TKI 258 were conjugated on gold nanorods. The physical properties of gold nanorods were characterized by transmission electron microscope and UV vis spectrometer respectively. 2. The transmission electron microscope(TEM) image of the multifunctional gold nanorods showed that the GNRs were coated with uniform mesoporous silica(average 19.39nm+1.63 nm thickness) and had been dispersed uniformly. After the MDA MB 231 and MCF 7 cell were incubated with multifunctional gold nanorods, it could be located internalize into cell by endocytosis. The physical properties of gold nanorods were characterized by UV vis spectrometer and its absorption peaks at 515 nm and 860 nm. The dual target inhibitors TKI 258 and RGD had special absorption peaks at 360 nm and 204 nm, respectively. 3. There is no cytotoxicity observed on MDA MB 231 and MCF 7 cell while the concentration of multifunctional gold nanorods is 0 100 ?g/ml(p>0.05). The cytotoxicity was graded as level ? and IC50 value was 434.63?g/ml. 4. The expression of integrin ?v?3, which included both endogenous and radiation induced expression, was fully attenuated by TKI 258 p GNRs@m Si O2 RGD, while these changes have not been observed in MCF 7 cells. West blot assay also showed that TKI 258 p GNRs@m Si O2 RGD attenuated the VEGFR expression level.5. The clonogenic assay showed that addition of p GNRs@m Si O2 enhanced the radiosensitivity of MDA MB 231 cells after 6 MV X ray irradiation. TKI 258 p GNRs@m Si O2 RGD could further sensitize the MDA MB 231 cells to irradiation. Furthermore, TKI 258 p GNRs@m Si O2 RGD increased radiation induced DNA double strand breaks and apoptosis. DNA flow cytometric analysis indicated that TKI 258 p GNRs@m Si O2 RGD combined with irradiation significantly induced G2/M phase arrest in MDA MB 231 cells.Conclusion 1. Gold nanomaterials conjugated with dual target inhibitors( TKI 258 p GNRs@m Si O2 RGD) has been designed and developed as radiotherapy sensitizing agents. 2. the expression of integrin ?v?3 and VEGFR could be attenuated by multifunctional golad nanorods(TKI 258 p GNRs@m Si O2 RGD) through the enhanced radiosensitivity of MDA MB 231 cells after 6 MV X ray irradiation. It coule be due to a complete inactivation of endogenous and radiation induced ?v?3 in addition to the induction of the cell arrest at G2/M phase. 3. Although the mechanism of combination with TKI 258 p GNRs@m Si O2 RGD and radiation warrants further investigation, our study laid the experiment foundation to improve TNBC radiotherapy efficacy.