Overcoming the stromal barrier for targeted delivery of HPMA copolymers to pancreatic tumors

Abstract

Delivery of macromolecules to pancreatic cancer is inhibited by a dense extracellular matrix composed of hyaluronic acid, smooth muscle actin and collagen fibers. Hyaluronic acid causes a high intratumoral fluidic pressure which prevents diffusion and penetration into the pancreatic tumor. This study involves the breaking down of hyaluronic acid by treating CAPAN-1 xenograft tumors in athymic nu/nu mice with targeted N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers radiolabeled with (111)In for single photon emission computerized tomography (SPECT) imaging. Two targeting strategies were investigated including αvβ3 integrin and HER2 receptors. HPMA copolymers were targeted to these receptors by conjugating short peptide ligands cRGDfK and KCCYSL to the side chains of the copolymer. Results demonstrate that tumor targeting can be achieved in vivo after treatment with hyaluronidase. This approach shows promise for enhanced delivery of polymer-peptide conjugates to solid tumors.

Keywords: 2,2′-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride; 2-cyano-2-propyl dodecyl trithiocarbonate; APMA-CHX-A′′-DTPA; CPDT; CT; DMM; Dulbecco's modified eagle medium; EDTA; EPR; FBS; HA; HER2; HPMA; HPMA copolymer; Hyaluronidase; IFP; IMDM; Imaging; Isocove's modified dubellco's media; M(n); M(w); MA-GG-TT; MWCO; N-(2-hydroxypropyl)methacrylamide; N-methacryloylaminopropyl-2-amino-3-(isothiourea-phenyl)propyl-cyclohexane-1,2-diamine-N,N-N′,N′,N′′,N′′-pentaacetic acid; N-methacryloyl–glycyl–glycyl thiazolidine-2-thione; PBS; PDAC; PDI; PE; PET; Pancreatic cancer; RAFT; SEC; SMA; SPECT; Targeting; VA-044; enhanced permeability and retention; ethylenediaminetetraacetic acid; fetal bovine serum; human epidermal growth factor receptor 2; hyaluronic acid; intra-tumoral fluidic pressure; molecular weight cut-off; number average molecular weight; pancreatic ductal adenocarcinoma; phosphate buffered saline; phycoerythrin; polydispersity index; positron emission tomography; reversible addition–fragmentation chain transfer; single photon emission computerized tomography; size exclusion chromatography; smooth muscle actin; weight average molecular weight; x-ray computed tomography.