Preparation Of Chitosan-based Nanoparticles For Tumor-targeted Imaging And Treatment

Objective:Lung cancer is one of the leading causes of death among cancer patients,and non-small cell lung cancer(NSCLC)accounts for over 80%of lung cancers.Most of the NSCLC patients diagnosed at advanced stage and lost the chance of operation.The most feasible treatment for advanced NSCLC patients is the platinum-based combination chemotherapy,but the curative effect is still unsatisfactory.Although novel molecular targeted drugs have been developed in clinical treatment practice,the outcome of molecular targeted therapies is still restricted by the ambiguous molecular subtypes of NSCLC patients which are difficult to be defined to make sure patients with "druggable" mutations,and the inevitable emergence of drug-resistance.To resolve currently confronting difficulties in targeted molecular therapy,we present a novel strategy to construct self-assembled nanoparticles based on erlotinib(Er)and heptamethine cyanine(Cy7)modified chitosan(Cs)for efficient molecular targeted imaging and synergistic therapy of Er-sensitive(epidermal growth factor receptor-mutated)lung cancer.Methods:Firstly,we synthesized alkylated Cy7 derivatives and azide-modified chitosan derivatives.Next the alkylated Cy7 derivatives and Er were interacted with Cs derivative bearing azide groups by click chemistry to obtain a new polymer derivative,named as CE7.Then the CE7 self-assembled nanoparticles(CE7Ns)were prepared and the physiochemical properties of CE7 and CF7Ns were investigated using infrared(IR)spectra,nuclear magnetic resonance(NMR)spectroscopy,dynamic light scattering(DLS),atomic force microscopy(AFM),UV-Vis spectra,and fluorescent(FR)spectra.Subsequently,the Er-sensitive tumor recognition ability of CE7Ns was determined by confocal microscopy and flow cytometry.Cell proliferation inhibition assay,cell cycle arrest,apoptosis assay were adopted to test the anti-cancer activity of CE7Ns.Finally,the imaging and tumor growth inhibition effects of CE7Ns were investigated in non-small cell lung cancer xenografts tumor model in nude mice.Results:IR,NMR,UV-Vis,and FR spectra confirmed that Er and Cy7 have been successfully linked to the Cs backbone.The grafting amount of Er and Cy7 were 0.48 and 0.016 g/g by using UV-Vis and FR spectrophotometry,respectively.The experimental results showed that CE7Ns were stable and uniform with particle size around 200 nm.CE7Ns demonstrated a pH-dependent drug release properties.Confocal and flow cytometry experiments showed that CE7Ns had a high ability to recognize target cells and CE7Ns were mainly located in the cytoplasm of cells.The cytotoxicity experiment showed that CE7Ns could improve the therapeutic effects of Er,and CE7Ns could be used for photodynamic therapy under near infrared irradiation to further improve the therapeutic effects.In vivo,CE7Ns could target and accumulate in lung tumor tissues.The in vivo anti-tumor experiments provided the strong evidence that the photodynamic therapy can improve the anti-tumor effects of CE7Ns.Conclusion:In this study,CE7Ns were successfully developed for imaging and treatment of Er-sensitive lung cancer.These results suggested that CE7Ns are promising tumor targeting carriers for simultaneous fluorescence imaging and molecular-targeted/photodynamic combination therapy.It also provides an important reference for improving the effectiveness of molecular targeted drug therapy and individualized treatment of lung cancer.