1195771-65-3Relevant academic research and scientific papers
Intracellular delivery of a proapoptotic peptide via conjugation to a RAFT synthesized endosomolytic polymer
Duvall, Craig L.,Convertine, Anthony J.,Benoit, Danielle S.W.,Hoffman, Allan S.,Stayton, Patrick S.
, p. 468 - 476 (2010)
Peptides derived from the third B-cell lymphoma 2 (Bcl-2) homology domain (BH3) can heterodimerize with antiapoptotic Bcl-2 family members to block their activity and trigger apoptosis. Use of these peptides presents a viable anticancer approach, but delivery barriers limit the broad application of intracellular-acting peptides as clinical therapeutics. Here, a novel diblock copolymer carrier is described that confers desirable pharmaceutical properties to intracellular-acting therapeutic peptides through site-specific molecular conjugation. This polymer was prepared using reversible addition-fragmentation chain transfer (RAFT) to form a pyridyl disulfide end-functionalized, modular diblock copolymer with precisely controlled molecular weight (Mn) and low polydispersity (PDI). The diblock polymer (Mn 19,000 g/mol, PDI 1.27) was composed of an N-(2-hydroxypropyl) methacrylamide (HPMA) first block (Mn 13,800 g/mol, PDI 1.13) intended to enhance water solubility and circulation time. The second polymer block was a pH-responsive composition designed to enhance endosomal escape and consisted of equimolar quantities of dimethylaminoethyl methacrylate (DMAEMA), propylacrylic acid (PAA), and butyl methacrylate (BMA). A hemolysis assay indicated that the diblock polymer undergoes a physiologically relevant pH-dependent switch from a membrane inert (1% hemolysis, pH 7.4) to a membrane disruptive (61% hemolysis, pH 5.8) conformation. Thiol-disulfide exchange reactions were found to efficiently produce reversible polymer conjugates (75 mol % peptide reactivity with polymer) with a cell-internalized proapoptotic peptide. Microscopy studies showed that peptide delivered via polymer conjugates effectively escaped endosomes and achieved diffusion into the cytosol. Peptide-polymer conjugates also produced significantly increased apoptotic activity over peptide alone in HeLa cervical carcinoma cells as found using flow cytometric measurements of mitochondrial membrane depolarization (2.5-fold increase) and cell viability tests that showed 50% cytotoxicity after 6 h of treatment with 10 μM peptide conjugate. These results indicate that this multifunctional carrier shows significant promise for proapoptotic peptide cancer therapeutics and also as a general platform for delivery of peptide drugs with intracellular targets.
RAFT-synthesized graft copolymers that enhance pH-dependent membrane destabilization and protein circulation times
Crownover, Emily,Duvall, Craig L.,Convertine, Anthony,Hoffman, Allan S.,Stayton, Patrick S.
, p. 167 - 174 (2011)
Here we describe a new graft copolymer architecture of poly(propylacrylic acid) (polyPAA) that displays potent pH-dependent, membrane-destabilizing activity and in addition is shown to enhance protein blood circulation kinetics. PolyPAA containing a single telechelic alkyne functionality was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization with an alkyne-functional chain transfer agent (CTA) and coupled to RAFT polymerized poly(azidopropyl methacrylate) (polyAPMA) through azide-alkyne [3 + 2] Huisgen cycloaddition. The graft copolymers become membrane destabilizing at endosomal pH values and are active at significantly lower concentrations than the linear polyPAA. A biotin terminated polyPAA graft copolymer was prepared by grafting PAA onto polyAPMA polymerized with a biotin functional RAFT CTA. The blood circulation time and biodistribution of tritium labeled avidin conjugated to the polyPAA graft copolymer was characterized along with a clinically utilized 40 kDa branched polyethylene glycol (PEG) also possessing biotin functionalization. The linear and graft polyPAA increase the area under the curve (AUC) over avidin alone by 9 and 12 times, respectively. Furthermore, polyPAA graft copolymer conjugates accumulated in tumor tissue significantly more than the linear polyPAA and the branched PEG conjugates. The collective data presented in this report indicate that the polyPAA graft copolymers exhibit robust pH-dependent membrane-destabilizing activity, low cytotoxicity, significantly enhanced blood circulation time, and increased tumor accumulation.
Temperature responsive polymer-supported TEMPO: An efficient and recoverable catalyst for the selective oxidation of alcohols
Chen, Tao,Xu, Zhenkai,Zhou, Lei,Hua, Laiyu,Zhang, Shuo,Wang, Jiping
supporting information, p. 419 - 422 (2019/01/08)
This study aimed to combine the advantages of homogeneous catalysis and heterogeneous catalysis by immobilizing TEMPO into a water-soluble temperature responsive polymer. The supported TEMPO was water soluble and displayed excellent activity in the selective oxidation of alcohols below the LCST and can be easily recovered.
COMPOSITIONS AND METHODS FOR CONTROLLED LOCALIZED DELIVERY OF BONE FORMING THERAPEUTIC AGENTS
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Sheet 3, (2014/10/04)
The present invention provides compositions and methods for providing controllable local delivery of a therapeutic agent to promote bone formation. In certain embodiments, the invention is used as a treatment for a subject with osteoporosis, bone cancer or bone fracture. The invention provides a therapeutic agent that is tethered to a polymer to form a therapeutic-tethered macromer, where the therapeutic agent is controllably released from the conjugate by degradation of the tether. In certain embodiments, the therapeutic agent is an inhibitor of GSK3β. In certain embodiments, the composition of the invention is specifically targeted to a site in need of bone formation.
Matrix metalloproteinase responsive, proximity-activated polymeric nanoparticles for siRNA delivery
Li, Hongmei,Yu, Shann S.,Miteva, Martina,Nelson, Christopher E.,Werfel, Thomas,Giorgio, Todd D.,Duvall, Craig L.
, p. 3040 - 3052 (2013/07/26)
Small interfering RNA (siRNA) has significant potential to evolve into a new class of pharmaceutical inhibitors, but technologies that enable robust, tissue-specific intracellular delivery must be developed before effective clinical translation can be achieved. A pH-responsive, smart polymeric nanoparticle (SPN) with matrix metalloproteinase (MMP)-7-dependent proximity-activated targeting (PAT) is described here. The PAT-SPN is designed to trigger cellular uptake and cytosolic delivery of siRNA once activated by MMP-7, an enzyme whose overexpression is a hallmark of cancer initiation and progression. The PAT-SPN is composed of a corona-forming polyethylene glycol (PEG) block, an MMP-7-cleavable peptide, a cationic siRNA-condensing block, and a pH-responsive, endosomolytic terpolymer block that drives self-assembly and forms the PAT-SPN core. With this novel design, the PEG corona shields cellular interactions until it is cleaved in MMP-7-rich environments, shifting the SPN ζ-potential from +5.8 to +14.4 mV and triggering a 2.5 fold increase in carrier internalization. The PAT-SPN exhibits pH-dependent membrane disruptive behavior that enables siRNA escape from endo-lysosomal pathways. Intracellular siRNA delivery and knockdown of the model enzyme luciferase in R221A-Luc mammary tumor cells is significantly increased by MMP-7 pre-activation (p 0.05). These combined data indicate that the PAT-SPN provides a promising new platform for tissue-specific, proximity-activated siRNA delivery to MMP-rich pathological environments. Copyright
