Abstract
Purpose The aim of this study was to determine whether co-administration of hedgehog (Hh) pathway inhibitor cyclopamine (CYP) and microtubule stabilizer docetaxel (DTX) as polymer-drug conjugates, methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylenecarbonate-graft-dodecanol-graft-cyclopamine) (P-CYP) and methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol-graft-docetaxel) (P-DTX) could synergistically inhibit orthotopic pancreatic tumor growth in NSG mice.
Methods P-DTX and P-CYP were synthesized from mPEG-b-PCC through carbodiimide coupling reaction and characterized by H-1-NMR. The micelles were prepared by film hydration and particle size was measured by dynamic light scattering (DLS). Cytotoxicity, apoptosis and cell cycle analysis of P-DTX and P-CYP were evaluated in MIA PaCa-2 cells. In vivo efficacy of P-DTX and P-CYP were evaluated in NSG mice bearing MIA PaCa-2 cells derived orthotopic pancreatic tumor.
Results P-CYP and P-DTX self-assembled into micelles of <90 nm and their combination therapy efficiently inhibited the proliferation of MIA PaCa-2 cells, induced apoptosis and cell cycle arrest at M-phase more efficiently than P-CYP and P-DTX monotherapies. Furthermore, the combination therapy of P-CYP and P-DTX significantly reduced Hh component expression compared to P-CYP alone as determined by Western blot analysis. Lastly, the combination therapy induced greater inhibition of orthotopic pancreatic tumor growth in NSG mice compared to their monotherapies.
Conclusion Combination of polymer conjugated anticancer drug (P-DTX) with polymer conjugated Hh inhibitor (P-CYP) enhanced pancreatic cancer cell killing, apoptosis as well as in vivo tumor growth inhibition with no obvious toxicities.