Targeting Arginine-Dependent Cancers with Arginine-Degrading Enzymes: Opportunities and Challenges.
	    		
		   		
	    	
    	
    	
   		
        
        	
        	
        	
        		- Author:
	        		
		        		
		        		
			        		Melissa M PHILLIPS
			        		
			        		
			        		
			        			1
			        			
			        		
			        		
			        		
			        		
			        		;
		        		
		        		
		        		
			        		Michael T SHEAFF
			        		
			        		;
		        		
		        		
		        		
			        		Peter W SZLOSAREK
			        		
			        		
		        		
		        		
		        		
		        		
		        			
			        		
			        		Author Information
			        		
		        		
		        		
			        		
			        		
			        			1. Center for Molecular Oncology, Barts Cancer Institute - a Cancer Research UK Centre of Excellence, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, London, UK. p.w.szlosarek@qmul.ac.uk
			        		
		        		
	        		
        		 
        	
        	
        	
        		- Publication Type:Review
 
        	
        	
        		- Keywords:
        			
	        			
	        				
	        				
			        		
				        		Neoplasms;
			        		
			        		
			        		
				        		Arginine;
			        		
			        		
			        		
				        		Argininosuccinate synthetase;
			        		
			        		
			        		
				        		Argininosuccinate lyase;
			        		
			        		
			        		
				        		ADI-PEG20;
			        		
			        		
			        		
				        		Arginase;
			        		
			        		
			        		
				        		Drug combinations
			        		
			        		
	        			
        			
        		
 
        	
            
            	- MeSH:
            	
	        			
	        				
	        				
				        		
					        		Arginase;
				        		
			        		
				        		
					        		Arginine;
				        		
			        		
				        		
					        		Argininosuccinate Lyase;
				        		
			        		
				        		
					        		Argininosuccinate Synthase;
				        		
			        		
				        		
					        		Biomarkers;
				        		
			        		
				        		
					        		Carcinoma, Hepatocellular;
				        		
			        		
				        		
					        		Drug Combinations;
				        		
			        		
				        		
					        		Epigenomics;
				        		
			        		
				        		
					        		Glioblastoma;
				        		
			        		
				        		
					        		Humans;
				        		
			        		
				        		
					        		Kidney Neoplasms;
				        		
			        		
				        		
					        		Lymphoma;
				        		
			        		
				        		
					        		Melanoma;
				        		
			        		
				        		
					        		Sarcoma;
				        		
			        		
				        		
					        		Urea;
				        		
			        		
				        		
					        		Urologic Neoplasms
				        		
			        		
	        			
	        			
            	
            	
 
            
            
            	- From:Cancer Research and Treatment
	            		
	            		 2013;45(4):251-262
	            	
            	
 
            
            
            	- CountryRepublic of Korea
 
            
            
            	- Language:English
 
            
            
            	- 
		        	Abstract:
			       	
			       		
				        
				        	Arginine deprivation is a novel antimetabolite strategy for the treatment of arginine-dependent cancers that exploits differential expression and regulation of key urea cycle enzymes. Several studies have focused on inactivation of argininosuccinate synthetase 1 (ASS1) in a range of malignancies, including melanoma, hepatocellular carcinoma (HCC), mesothelial and urological cancers, sarcomas, and lymphomas. Epigenetic silencing has been identified as a key mechanism for loss of the tumor suppressor role of ASS1 leading to tumoral dependence on exogenous arginine. More recently, dysregulation of argininosuccinate lyase has been documented in a subset of arginine auxotrophic glioblastoma multiforme, HCC and in fumarate hydratase-mutant renal cancers. Clinical trials of several arginine depletors are ongoing, including pegylated arginine deiminase (ADI-PEG20, Polaris Group) and bioengineered forms of human arginase. ADI-PEG20 is furthest along the path of clinical development from combinatorial phase 1 to phase 3 trials and is described in more detail. The challenge will be to identify tumors sensitive to drugs such as ADI-PEG20 and integrate these agents into multimodality drug regimens using imaging and tissue/fluid-based biomarkers as predictors of response. Lastly, resistance pathways to arginine deprivation require further study to optimize arginine-targeted therapies in the oncology clinic.