Compositions, delivery systems, and methods useful in tumor therapy

A composition comprising a first component and a second component, wherein the first and second components are coupled via a linking component, wherein the linking component comprises a neprilysin (NEP) cleavage site, wherein the NEP cleavage site can be cleaved by NEP, wherein cleavage of the NEP cleavage site separates the first component from the second component,

• wherein the first component comprises a therapeutic agent, a detection agent, or a combination thereof,
• wherein the second component comprises a ligand,
• wherein the ligand comprises the structure (I):
• or a salt, tautomer, prodrug or stereoisomer thereof, wherein:
• L1 and L2 each individually is a bond or comprises an optionally substituted linker moiety;
• G is a triazole, a carbon-carbon double bond, or an amide;
• M is methionine;
• R is H or comprises an optionally substituted linker moiety;
• R1 is H or C1-C6 alkyl;
• y1 and y2 are each individually 0 or 1;
• and
• SEQ is an amino acid sequence comprising from 2 to 20 amino acids selected from natural amino acids, non-natural amino acids, or a combination of natural and non-natural amino acids,
• wherein each linker moiety optionally comprises a linkage to the NEP cleavage site, a linkage to a second ligand, a linkage to a reporter moiety, a linkage to an albumin binding moiety, a linkage to a peptide ligand, or combinations thereof,
• wherein one and only one of L1, L2, and R comprises a linkage to the NEP cleavage site.