| The traditional chemotherapeutic drugs play an important role in the treatment of malignant tumors.Because the drugs can reach all parts of the body in the blood stream.However,the conventional chemotherapy drugs are easy not only to be removed by metabolism dependent process but also to be toxic to normal tissues.Therefore,in order to improve effective accumulation of chemotherapeutic drugs in tumor tissue and minimize distribution in other organs,drug delivery system for treatment of cancer has been attracted much attention.Traditional nanocarriers that are used as transporters of chemical drugs such as liposomes,polymers,micelles,and inorganic material provide various advantages which are enhanced stability and biocompatibility.However,they are difficult to cross the tissue barriers such as the blood-brain barrier due to the lack of targeting at the tumor sites in the absence of modification of nanoparticles with genetic materials,protein,and ligands.Therefore,for the steps leading to improvement in preferential targeting,the use of various ligands that can give abilities to recognize tumor tissue and penetrate blood-brain barrier has been emerging.Liposomes are the most commonly used nanocarriers because of their low toxicity,biodegradability,simultaneous delivery of hydrophobic drugs,and easy modification.Liposomes and chemical drugs such as paclitaxel,doxorubicin and irinotecan have been used in clinical practice.However,some physiological disorders with severe side effects are still unavoidable.Many studies have found that cholesterol,the major component of liposomes,can cause side effects such as cardiopulmonary hypertension by activating allergic reactions related to complement activation.Besides,most chemotherapy drugs and drug delivery systems are only for the tumor cells,ignore the effect of microenvironment formed by tumor growth.The tumor microenvironment consisted of the surrounding blood vessels,immune cells,and extracellular matrix and also it is considered to play a role to activate tumor progression as well as metastasis.Tumor cells can become their own’accomplice’ by ’taming’ other cells in the tumor microenvironment with immunosuppression leading to multi-drug resistance.Therefore,recently researchers have tried to modify the immunoregulatory molecules with the nanocarriers and deliver chemotherapeutic drugs to the tumor site to overcome drug resistance.However,there are still drawbacks such as low efficiency and stability which are a major concern in clinical trials.To solve these problems mentioned above,we have utilized ginsenoside Rg3 which has similar to steroid structure with cholesterol(the major structural components of liposome).Ginsenoside Rg3 has many potentials such as the hydrophilic tail carrying good physicochemical properties in glucose-based side chain(active targeting ability),and great anticancer activity(cooperating with the chemotherapeutic drug in combination with anticancer ability).This is the first discovery of the construction of a new multifunctional liposome based on ginsenoside Rg3.Glioma and breast cancer resistant cells were regarded as model cancers and treated with ginsenoside Rg3 and paclitaxel.We investigated the effects of tumor targeting,trans-blood-brain barrier,regulation and activation of the immune microenvironment.Firstly,a novel ginsenoside Rg3 liposome(Rg3-PTX-LPs)loaded with paclitaxel was prepared by membrane hydration method,its particle size,potential,and dispersion coefficientand were measured by Malvern laser particle size analyzer.The drug loading and encapsulation efficiency were determined by phase chromatography.The experimental results show that the particle size,potential and encapsulation rate of Rg3-PTX-LPs are better than traditional cholesterol liposomes.Secondly,the treatment and mechanism of the ginsenoside Rg3 liposome on glioma were investigated by MTT assay and apoptosis assay in vitro.The results showed lower IC50 value with the ginsenoside Rg3 liposomes(Rg3-PTX-LPs)loaded with paclitaxel and significantly promoted late apoptosis of tumor cellscompared to traditional cholesterol liposomes(C-PTX-LPs).By culturing mouse bone marrow-derived macrophages(BMDM)and inducing polarization,a model of tumor microenvironment in vitro was constructed to investigate the regulation of Rg3-PTX-LPs on macrophages.The experimental results show that Rg3-PTX-LPs can induce M2 macrophages that promote tumor proliferation into antitumor Ml macrophages.The targeting and tumor penetration ability of Rg3 liposomes in vitro were determined by flow cytometry and laser confocal.In vivo test,it showed that Rg3 liposomes have potent brain tumor targeting ability compared with traditional cholesterol liposomes.In vivo efficacy showed that Rg3-PTX-LPs can promote T cell immune response,up-regulate CD8+T cell population,and increase M1/M2 ratio by activating the immune microenvironment in gliomas in vivo compared with untreated groups while Treg and MDSC significantly prolonged the mid-term survival of C6 mice,which was 2.6 times higher than that of the untreated group.Finally,the role and mechanism of novel ginsenoside Rg3 liposome against breast cancer resistance were investigated.MTT assay and apoptosis assay were used to investigate the in vitro toxicity of drugs and drug-loaded liposomes to MCF-7/T.The results showed that Rg3-PTX-LPs increased the sensitivity of MCF-7/T cells to paclitaxel,and its IC50 value was nearly 4-fold lower than that of the PTX group.Cellular apoptosis assay showed that the apoptotic rate of the Rg3-PTX-LPs group was nearly 4 times higher compared with that of the PTX group.By regulating TAM in the tumor microenvironment in vitro,Rg3-PTX-LPs can modulate TAM to significantly induce M2 macrophages into M1 macrophages.In the PD-L1 assay in vitro,both free Rg3 and Rg3 liposomes down-regulated the expression of PD-L1,and the down-regulation of Rg3 liposomes was effective than that of free Rg3.The anti-breast resistance effect in vivo and the regulation of tumor microenvironment showed that compared with the PTX group,the Rg3-PTX-LPs group had the great anti-tumor effect,as evidenced by a slowdown in growth of cancer.The experimental results of Tunnel showed that Rg3-PTX-LPs can significantly promote apoptosis and necrosis of breast cancer tumor tissues resistant to PTX.Analysis of the microenvironment of mouse tumor tissue after treatment found that Rg3-PTX-LPs can regulate THE to some extent,inhibit the survival of tumor neovascularization and reduce the expression of tumor-associated fibroblasts.In summary,the ginsenoside Rg3 liposome is a valuable nanocarrier with high preferential targeting effect and low toxicity.Furthermore,the ginsenoside Rg3 liposome can penetrate into blood-brain barrier with paclitaxel,it promises to be a multifunctional synergistic therapy to regulate microenvironment and activate tumor immunity. |
PDF Full Text Request