Construction Of Hyaluronidase-activated All In One Probe And Its Application In The Diagnosis And Treatment Of Triple-negative Breast Cancer

Objective:As the most aggressive breast cancer,triple negative breast cancer（TNBC）has poor prognosis due to the difficulty in early diagnosis and lack of targeted treatment means.Therefore,developing novel methods for the early diagnosis and targeted treatment of TNBC is very important.Molecular imaging-based theranostic probes are equipped with multiple functions including tumor detection and anti-tumor treatment.As novel therapy means,photothermal therapy,photodynamic therapy and chemodynamic therapy have attracted much attention because of less trauma and side effect.Taking the above points into consideration,this thesis is aimed at developing all in one theranostic probes and studying their applications in the precise diagnosis and treatment of TNBC.The main work is as follows:1.A theranostic probe named as HA-ICG-PDA was constructed by introducing the near-infrared fluorophore indocyanine green（ICG）and polydopamine（PDA）into the targeting unit hyaluronic acid（HA）,which has the near-infrared imaging and photothermal/photodynamic synergetic therapy abilities.Then,the application of the probe in the imaging diagnosis and targeted treatment of TNBC was studied both at cellular level and in vivo.This work may provide new means for the precise diagnosis and treatment of TNBC.2.On the basis of the above work,a new probe named as HA-ICG-Fe-PDA was developed by loading Fe³⁺,which has the fluorescence and magnetic resonance dual-modal imaging ability.Besides,the probe has the function of chemodynamic therapy.Thus,HA-ICG-Fe-PDA may achieve better diagnosis and treatment results.Method:1.The probe HA-ICG-PDA was prepared by covalently incorporating ICG and PDA into HA via condensation reactions.Then,the probe was characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,X-ray diffraction,transmission electron microscopy,dynamic light scattering,and thermogravimetric analysis.The responses of HA-ICG-PDA to hyaluronidase was investigated by fluorescence spectroscopy.The commercial reactive oxygen probe DCFH-DA was used to evaluate the photodynamic performance of the system and the infrared thermal imager was used to study the photothermal performance.The cellular imaging ability of the probe was assessed by laser confocal imaging and flow cytometry.The killing ability to cells was studied by MTT method and Calcein-AM/PI staining.The imaging performance of the probe in vivo was studied by small animal fluorescence imaging system.The anti-tumor ability was evaluated by monitoring tumor size and weight and the biosafety was assessed by mouse weight,blood biochemical indexes and histologic sections assay.2.Fe-PDA was synthesized by introducing Fe³⁺to PDA with coordinate bond.The probe HA-ICG-Fe-PDA was further prepared by incorporating ICG and Fe-PDA into HA.The characterization of the probe,the responses of the probe to Hyal as well as the imaging and killing ability of the probe were studied as the above methods.Moreover,the commercial reagent TMB was used to evaluate the chemodynamic performance of HA-ICG-Fe-PDA.And the magnetic resonance imaging in vivo was conducted on the small animal magnetic resonance imaging system.Result:1.The probe HA-ICG-PDA exhibits fluorescence enhanced response to Hyal with high sensitivity and selectivity.The reaction system of the probe and Hyal has good photodynamic and photothermal performance.Studies at cellular level show that HA-ICG-PDA can selectively penetrate MDA-MB-231 cells.Besides,HA-ICG-PDA shows strong killing ability to MDA-MB-231 cells with negligible toxicity to MCF-10A cells.Moreover,the probe can be used for the targeted imaging of tumor in TNBC model mice.With the 808 nm laser irradiation,the probe has prominent anti-tumor ability with little side effect.2.The probe HA-ICG-Fe-PDA has higher sensitivity than HA-ICG-PDAand shows distinct T2 magnetic resonance signal.The reaction system of HA-ICG-Fe-PDA and Hyal has favourable photodynamic,photothermal and chemodynamic performance.Studies at cellular level reveal that HA-ICG-Fe-PDA can selectively penetrate MDA-MB-231 cells.In addition,the probe shows significant killing ability to MDA-MB-231 cells with negligible toxicity to MCF-10A cells.HA-ICG-Fe-PDA can be used for the fluorescence and magnetic resonance dual-modal imaging in TNBC model mice.Moreover,the probe itself exhibits tumor-inhibiting ability.With the 808 nm laser irradiation,the tumor-inhibiting ability is greatly enhanced,which can accomplish the efficient and harmfulless tumor treatment.Conclusion:Two theranostic probes with molecular imaging and synergetic treatment abilities have been developed in this thesis.These probes are biocompatible and can be used for the targeted imaging and efficient treatment of TNBC,which may have wide prospect in the early diagnosis and precise therapy of TNBC.