Construction And Anti-cancer Evaluation Of Nanodrugs Based On Parthenolide Skeleton

In recent years,the incidence and mortality of cancer around the world are all increased gradually,which has aroused widespread concern.Among various cancer treatments,chemotherapy is still an efficient treatment with systemic therapeutic effect.But in clinical,small molecular anticancer drugs have some inherent disadvantages,including low bioavailability,large side effects,rapid blood clearance,short of targeting to tumor sites,severe multidrug resistance（MDR）and so on.For overcoming above problems,a new concept of amphiphilic drug-drug conjugates（ADDC）was proposed by our group in 2014.Then we constructed a series of carrier-free and self-delivery small molecule nanodrugs by the self-assembly of various ADDCs,which exhibited good anti-tumor activities.Natural anti-cancer compounds,parthenolide and its derivatives,have high activity and unique advantages for the treatments of malignant tumors such as glioma,leukemia and colon cancer.However,they also face the same problems,such as poor water solubility,difficult drug delivery etc.In this paper,we plan to adopt ADDC strategy to construct some amphiphilic conjugates from parthenolide and its derivatives with other anti-cancer drugs or excipients.They can self-assemble in water to produce nanodrugs to achieve carrier-free self-delivery and synergistic treatment.The detailed research contents and conclusions are displayed as follows:（1）Synthesis,preparation and anti-cancer activity evalution in vitro of amphiphilic irinotecan-mlampomagnolide B conjugate and its nanodrug.At first,the hydroxyl group in hydrophobic mlampomagnolide B was activated by 1,1’-carbonylbis（1,2,4-triazole）and then coupled with hydrophilic irinotecan to produce an amphiphilic conjugate with a linkage of degradable carbonate bond.The chemical structure of the resulting product Ir-MMB was confirmed by ¹H NMR,¹³C NMR,MS,fluorescence spectra and FTIR spectra.Due to its amphiphilic properties,Ir-MMB conjugate can self-assemble into nanoparticles in water.The results of DLS and TEM measurments showed that the average diameter of Ir-MMB nanoparticles was about 122.1 nm with spherical morphology.They can disperse well in water.The drug release experiments in vitro exhibited that the cumulative release of Ir-MMB nanoparticles was only 10%under the normal condition（pH=7.4）,but reached up to 50%under the tumor environment（pH=5.0）for 48 h.The results of flow cytometry and laser confocal microscopy demonstrated that Ir-MMB nanoparticles could be entered into cells by endocytosis within 6 h.MTT assay confirmed that Ir-MMB nanoparticles had low toxicity to normal cells,but high toxicity to cancer cells and inhibited their proliferation effectively.The apoptosis experiments indicated that the apoptosis rate of Ir-MMB nanoparticles was about 50%within 24 h.（2）Synthesis and characterization of nanodrugs from PEGylated parthenolide and its derivatives.Through the esterification,amphiphilic prodrugs（MMB-PEGs）were obtained by coupling mlampomagnolide B and the single carboxyl group terminated PEG with different molecular weights.Through Michael addition reaction,the amphiphilic derivative of parthenolide（PTL-PEGs）was obtained by coupling parthenolide and the single amino group terminated PEG with different molecular weights.The chemical structure of resulting products was confirmed by ¹H NMR,LC-MS and UV-Vis spectra.The DLS and TEM results indicated that all of them could self-assemble into spherical nanoparticles in water.The diameter of MMB-PEGs nanoparticles was about 130.3 nm and 102.3 nm respectively when the averaged molecular weight of PEG was 550 and 1000.Similarly,the diameter of PTL-PEGs nanoparticles was about 192.0 nm and 121.7 nm respectively when the averaged molecular weight of PEG was 550 and 1000.