Fluorinated Polymersome Targeted Deliver SiRBBP4 And Temozolomide For Synergistic Treatment Of Glioma

Glioma as one of the most incurable tumour,is difficult to treat because of its rapid growth and aggressiveness.The standard method for glioma therapy in clinical is surgical removal of tumour followed by drug treatment.However,due to the location of glioma,the surgical operation is difficult to completely remove the glioma tumour tissue/cells,results in high recurrences.Temozolomide(TMZ)is a first-line drug for the treatment of glioma,which can damage the DNA molecules of tumor cells by alkylation,and finally leads to cell death.However,O6-methylguanine-methyltrasferase(MGMT)can quickly transfer the methyl group in O6-Me G caused by TMZ to its own active cysteine residue.This transferring process can repair the TMZ damaged DNA,and consequently decrease the sensitivity of TMZ.Previous studies have showed that retinoblastoma binding protein 4(RBBP4)is able to modulate the sensitivity of TMZ to tumor cells by regulating the expression of MGMT and other DNA repairing proteins,that downregulation of RBBP4 can enhance the sensitivity of TMZ to glioma.Here we reported a glioma targeted polymersomal drug delivery system prepared from fluorinated guanidino-containing polymers for the delivery of siRNA(siRBBP4)and TMZ to treat glioma in mice.The addition of siRBBP4 is expected to increase the sensitivity of TMZ and to achieve the synergistic effect for the therapy of glioma.Gel electrophoresis and ultraviolet(UV)absorption results showed that these polymersomes can effectively loaded siRNA and TMZ,with a loading content of 10%,and 5%,respectively.Dynamic light scattering(DLS)results showed that these drug loaded polymersomes had a particle size of 90 nm with good uniformity(PDI = 0.13).Cell experiment results showed that the polymersomes displayed excellent biocompatibility.Furthermore,the modification of Angiopep-2 peptide enhanced the targetability of polymersomes,that Angiopep-2 functionized polymersome displayed 2.2 and 2.0-fold enhanced cell taken up ability than its non-targeted counterpart in U87-MG and U251-MG,respectively.Moreover,the results of the blood-brain barrier model penetration testing proved that the polymersomes modified with Angiopep-2 have the potential to cross the blood-brain barrier.Compared with control siRNA(si Scr)and TMZ co-loaded Angiopep-2 modified polymersome(Ang-PS@(si Scr&TMZ)),siRBBP4 and TMZ loaded nanomedicinecounterpart(Ang-PS@(siRBBP4&TMZ))caused more DNA damage and more apoptosis of tumor cells.These results indicated that this polymersomal drug delivery system co-loaded with siRBBP4 and TMZ has potent therapeutic potential for glioma.In order to investigated the in vivo targetability and therapeutic effect of Ang-PS@(siRBBP4&TMZ),orthotopic U87MG-luc glioma model was constructed for further studies.In vivo imaging and ex vivo quantification found that the Angiopep-2 functionized polymersomes had the highest accumulation in the brain tumour,that was three times of non-targeted polymersomes at 4 hours post injection.The treatment results showed that Ang-PS@(siRBBP4&TMZ)had the best anti-tumor effect,that with the slowest tumor growth and tumor shrinkage was happed in the later stages.Moreover,minimal changes in body weight and the longest survival(47 days)was further achieved by Ang-PS@(siRBBP4&TMZ)in all tested groups.Immunohistochemistry verified the regulation of MGMT by RBBP4,that by delivering siRBBP4 into glioma cells to block the synthesis of RBBP4,the expression of MGMT was decreased and the repair ability to damaged DNA is reduced,and consequently improves the treatment effect of TMZ.In summary,we developed a glioma-targeted polymersomal delivery system that can co-load siRNA and TMZ,with effective aggregation in brain tumour.This polymersomal nanomedicines loaded with siRBBP4 and TMZ displayed potent synergistic therapeutic effect,and are effective for tumour cells killing both in in vitro and in vivo,showing great promise for glioma treatment.