Metabolomic Study Of Breast Cancer To The Treatment Of Nano-drugs

With the rapid development of nano-biotechnology and extensive combination use of multi-drugs in clinic,more and more drug delivery systems(DDS)based on nano-carrier have been investigated.Due to their good biocompatibility and biodegradability,organic nanoparticles such as lipidosome,albumin,dendrimer and functional polymer show great potential in delievery multi-drugs.Methoxy poly(ethylene glycol)-poly(lactide-co-glycolide)(mPEG-PLGA)is one of those applicable functional nanocarriers.As an amphiphilic polymeric micelle,mPEG-PLGA could encapsulate hydrophilic doxorubicin and lipophilic paclitaxel,which are widely used anti-tumor drugs in the treatment of advanced breast cancer.With the aid of control led-release property and enhanced permeation and retention effect from mPEG-PLGA,doxorubicin and paclitaxel have exhibited improved tumor growth inhibition efficacy as well as reduced side-effects in previous studies.However,despite exhibiting good tumor cell inhibition efficacy both in vitro and in vivo,the understanding and evaluation of its holistic biological effects as well as its underlying mechanism under the improved tumor inhibition efficacy are still lacking.In consideration of the high morbidity and complicated subtypes of breast cancer,we chose human breast carcinoma cell line MCF-7 and 4T1 tumor-bearing mice as experimental models in this study.With the combination use of qRT-PCR and NMR-based and GC-FID/MS-based metabonomics,we aimed to conduct a systematic investigation of the biological effects of mPEG-PLGA nanocarrier and its encapsulated drugs on breast cancer models.Firstly,we used MCF-7 as our experimental model and investigated the metabolic phenotypical variations after cells being exposed to nanocarrier and encapsulated drugs at three different time points.We found that the interaction between copolymer nanocarrier and intracellular protein could induce the activation of glycolysis and TCA cycle as well as a depletion of amino acids in cells,which implied an active biological effect of this copolymer nanocarrier at metabolic level for the first time.Besides,the disturbance made by nanocarrier would be recovered or reverted after cells activating its compensation mechanism.The effect of encapsulated doxorubicin on glycolysis,nucleotides and amino acids metabolism got weaken with time,which implied an inadequate drug concentration and the possibility of activation of drug resistant protein.After being exposed to more than one encapsulated anti-tumor formulations,MCF-7 cells exhibited persistent protein hydrolysis,glycolysis and energy metabolism inhibition,activation of deglycosylation and down-regulation of PC to GPC,which hinted cell growth arrest and apoptosis with the combination use of multiple drugs.These results provide fundamental information of biological effects of amphiphilic copolymer nanocarrier and its encapsulated drugs on breast cancer cells,which facilitate the further understanding of these series of drug delivery systems.Secondly,to evaluate the drug efficacy of both free form and mPEG-PLGA encapsulated form of doxorubicin and paclitaxel as well as investigate their biological impacts on breast cancer in vivo.We employed healthy mice as control group and treated 4T1 tumor-bearing mice with saline,doxorubicin and paclitaxel in free form or mPEG-PLGA encapsulated form,and compared the metabolic profiling of serum and multiple organs from these four groups of mice.We found that tumor-bearing mice induced a systematic metabolic reprogramming associated with active glycolysis,TCA cycle,fatty acids oxidation and mobilization of nucleotides and amino acids in multiple organs to support the rapid growth of 4T1 cells.The treatment of free form of doxorubicin and paclitaxel could alleviate the nucleotides and energy supply on some degree in multiple organs;however,it also caused amino acids accumulation in liver.Besides,the up-regulation of fumarate in heart from mice treated with free form of doxorubicin and paclitaxel could be a result of cardiotoxicity from doxorubicin exposure.After being encapsulated by mPEG-PLGA,the stable fumarate level in heart hinted a reduced toxicity from nanocarrier encapsulating.Besides,the advantages of nanocarrier encapsulated drugs were manifested by the recovery of metabolic profiling of serum and kidney from tumor-bearing mice to a healthy state.The exposure of mPEG-PLGA encapsulated doxorubicin and paclitaxel induced oxidative stress in liver while liver could up-regulate the expression of G6PD and generate more NADPH to cope with this situation.These findings provide fundamental information on metabolic features of 4T1 breast cancer model and biological effects of free form and mPEG-PLGA encapsulated form of doxorubicin and paclitaxel for the first time,which demonstrated the reduced cardiotoxicity and improved drug efficacy of nanoparticle-encapsulated drugs over administration of free forms of drugs at molecular level.To sum up,this thesis gives a systematic study of the biological impact of amphiphilic copolymer mPEG-PLGA and its encapsulated drugs on breast cancer both in vivo and in vitro,which provides fundamental information of metabolic disturbance of breast cancer models after the exposure of this typical drug delivery system.Our research not only facilities the understanding of efficacy and working mechanism of mPEG-PLGA and its encapsulated drugs,but also helps to give hints on the design and optimization of this drug delivery system hereafter.