Design and Self Assembly of Tri-Terpene Peptide Conjugates and Their Interactions with EGFR and EGFR Mutant Receptors: An In Silico and In Vitro Study

In this work, we designed new terpenoid-peptide conjugates to target the epidermal growth factor receptor (EGFR) and its double mutant EGFR T790M/L858R which are implicated in many cancers. The peptides utilized were MEGPSKCCFSLALSH (MFSL), a new peptide sequence designed by mutating an ErbB2 targeting peptide, while the sequence VPWXE was derived from a peptide motif known to target tumor cells. Each of the peptides were conjugated to four terpenoids, 23-hydroxy betulinic acid (HB), oleanolic acid, perillic acid, and ursolic acid. Molecular docking and molecular dynamics (MD) simulations with the kinase domain of both the wild type and double mutant EGFR receptors revealed that the conjugates formed H-bonds and hydrophobic interactions with key residues in the hinge region, A-loop, and DFG motif, while in the case of the double mutant, interactions also occurred with C-terminal residues and with allosteric sites. MMGBSA analysis revealed higher binding energies for the double mutant. Six of the conjugates were synthesized and self-assembled into nanoassemblies and their impact on tumor cells expressing the wild type and double mutant receptor revealed that higher apoptosis was induced by MFSL conjugates, particularly in cells expressing the double mutant EGFR receptor. The HB and ursolate conjugates were found to be more potent against the tumor cell lines. Overall, these results indicate that these peptides and peptide conjugates can effectively bind to both the wild type and the T790M/L858R receptors to target tumor cells. Such peptide conjugates may be further potentially developed as therapeutic agents for further laboratory studies against tumors overexpressing EGFR.