Experimental Research On Target Treatment Of Pancreatic Cancer

BACKGROUND:Pancreatic ductal adenocarcinoma(PDAC)is one of the most intractable malignancy,with an only 6% 5-year survival rate.The dismal therapeutic effect is attributed to the chemotherapy resistance and unique pathophysiology with abundant inflammatory cytokines and abnormal hyperplasia of extracellular matrix.Nanotechonology based tagert drug delivery has advantegous on facilitating penetrating and accumulationg of drugs and overcoming chemoresistance.Based on the theory of “bone marrow mesenchymal stem cells and PDAC axis”,we employed exosomes(Exo)derived from BM-MSCs as PDACtargeting vehicles to surpass the restrictions of pathological ECM and increase the accumulation of therapeutics in tumor site.To overcome chemoresistance of PDAC,paclitaxel(PTX)and gemcitabine monophosphate(GEMP)– an intermediate product of GEM metabolism – were loaded in/on the exosomes to construct a co-delivery system.We hope this bio-nanomedicine can perform triple functions on removing the limitation of matrix,anti-matrix and overcoming chemoresistance.OBJECTIVE:To investigate whether different isolation methods of exosomes affect drug loading;to investigate whether exosomes derived from BM-MSCs could tagert and penetrate into PDAC effectively;to evaluate whether exosomal co-delivery system could inhibite tumor,degrade extracellular matrix and overcome chemoresistance.METHODS:(1)To investigate whether different isolation methods of exosomes affect drug loading by analyzing the loading dose and cell proliferation inhibition after employing diverse isolation methods and electroporation.(2)To investigate tagerting and penetrating capabilities of exosomes in PDAC orthotopic models by immunofluorescence staining and tumor spheroids.(3)Constructing exosomal co-delivery system and evaluating inhibitory effect on Mia Paca-2 cells and overcoming chemoresistance or not.(4)To investigate whether exosomal co-delivery system could inhibit tumor,degrade matrix and overcome chemoresistance.RESULTS:(1)We harvested exosomes with high purity and little diameter which exhibited preferable efficiency of drug loading and inhibition of cell proliferation.(2)Exosomes derived from BM-MSCs could tagert and penetrate in PDAC situ effectively.(3)Exosomal co-delivery system could overcome chemoresistance by enhancing accumulation of GEMP.(4)Exosomal co-delivery system could inhibit tumor and degrade matrix effectively by inside-out way.CONCLUSIONS:Density gradiant method benefited drug loading of exosomes employing electroporation;exosomal co-delivery system exhibited triple functions on tagerting and penetrating in PDAC effectively,degrading matrix and overcoming chemoresistance.