Anti-Inflammatory Activity Of Amino Acid Modified Camptothecin Prodrugs

Background: Sepsis is a life-threatening disease due to the organ dysfunction caused by host immune disorder.During the process of inflammation,excessive production of inflammatory cytokines by immune cells are capable of leading to tissue damage and organ failure and even death.However,clinical data indicate that the therapeutic efficiency of existing drugs for sepsis is not satisfactory.Therefore,it is important to develop novel drugs for sepsis treatment.It has been reported that camptothecin displays anti-inflammation activity by inhihibting topoisomerase 1.However,poor water-solubility and the rapid hydrolysis of Camptothecin-lactone to a ring-open carboxylate-form have limited Camptothecin（CPT）clinical development.Construction of CPT prodrugs has been proved an effective strategy for improving its therapeutic efficiency.L-amino acids,functional units of proteins,have excellent biosafety and biocompatibility and have significant advantages in construction prodrugs.However,there have few reports about the effects of the 20 naturally occurring amino acids on the activity of CPT.Therefore,we designed and synthesized the CPT-Amino Acid（CPT-AA）prodrugs and evaluated their anti-inflammation activity in viro and in vivo in this study.Objective: To evaluate the effects of 20 naturally occurring amino acids on the anti-inflammation activity of CPT;to screen out ideal CPT-AA prodrugs for sepsis treatment.Methods: Griess method,MTT method and q PCR were used to determine the effects of CPT-AA prodrugs on the production of NO,cytotoxicity and the m RNA expression levels of TNF-α in Lipopolysaccharide（LPS）-stimulated RAW 264.7cells.The effects of CPT-AA prodrugs on the survival rates of mice treated with LPS was evaluated after treating with different dosing,route,and timing of prodrugs administration.Results:1.Compared with hydrophobic amino acids,hydrophilic amino acids could generally improve the in vitro anti-inflammatory activity of CPT-AA prodrug.In vivo activity screening showed that CPT-cysteine（C-C）,CPT-lysine（C-K）and CPT-glycine（C-G）showed better therapeutic activity at a single dose of 1mg/kg.2.Compared with negatively charged,CPT-glutamic acid（C-E）,positively charged CPT-arginine（C-R）and C-K have stronger in vivo toxicity.3.After the optimization of drug dose,administration time and administration route,C-K can achieve better therapeutic effect under single dose,while C-C can achieve better therapeutic effect under multiple administration.In conclusion,we systematically studied the therapeutic effects of 20 CPT-AA prodrugs in vitro and in vivo,and obtained ideal compounds C-C and C-K.However,the therapeutic effects of these two compounds did not achieve the expected results.Therefore,this type of CPT-AA prodrug needs to be further optimized basing on these prodrugs.Nevertheless,this work provides rich theoretical support for the optimization of camptothecin for sepsis treatment.