Intracellular delivery of the reactive oxygen species generating agent D-penicillamine upon conjugation to poly-L-glutamic acid.
D-penicillamine is an aminothiol that is cytotoxic to cancer cells and generates dose dependent reactive oxygen species (ROS) via copper catalyzed oxidation. However, the delivery of D-pen to cancer cells remains a challenge due to its high hydrophilicity, highly reactive thiol group and impermeability to the cell membrane. To overcome this challenge, we investigated a novel poly-L-glutamic acid (PGA) conjugate of D-pen (PGA-D-pen) where D-pen was conjugated to PGA modified with 2-(2-pyridyldithio)-ethylamine (PDE) via disulfide bonds. Confocal microscopy and cell uptake studies showed that the fluorescently labeled PGA-D-pen was taken up by human leukemia cells (HL-60) in a time dependent manner. Treatment of HL-60, murine leukemia cells (P388) and human breast cancer cells (MDA-MB-468) with PGA-D-pen resulted in dose dependent cytotoxicity and elevation of intracellular ROS levels. PGA-D-pen induced apoptosis in HL-60 cells which was verified by Annexin V binding. The in vivo evaluation of the conjugate in the P388 murine leukemia model (intraperitoneal) resulted in significant enhancement in the survival of CD2F1 mice over vehicle control.
Wadhwa
Saurabh
S
Division of Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina 27599-7362, USA.
Mumper
Russell J
RJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002614:Chelating Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D018922:HL-60 Cells; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D015394:Molecular Structure; D009369:Neoplasms / Q000188:drug therapy; D010396:Penicillamine / Q000008:administration & dosage* / Q000737:chemistry* / Q000494:pharmacology; D011099:Polyglutamic Acid / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism*
D002614:Chelating Agents; D017382:Reactive Oxygen Species; D011099:Polyglutamic Acid; D010396:Penicillamine