Gershon Golomb

School of Pharmacy
Faculty of Medicine
The Hebrew University, Jerusalem 91120, Israel
Tel: +972-2-6758658; Fax: +972-2-6757126
Email: gershong@ekmd.huji.ac.il

Drug and Gene delivery by Nanoparticles

Nanoparticles to Extracellular Matrix for siRNA Delivery

Osteopontin (OPN) and the fibroblast growth factor receptor 1 (FGFR1) are proteins involved in cancer development and progression, thus inhibiting their expression utilizing siRNA technology represents a promising therapeutic strategy. Successful application in-vivo has significant obstacles due to the short half-life of siRNA molecules, their large molecular size and high negative charge density, which limit their cellular uptake. A safe and effective delivery system of siRNA would be targeted nanoparticles (NP) composed of biocompatible biomaterials (polymeric or lipoid based), which can protect the siRNA from degradation and at the same time providing effective uptake at the tumor site. In several important pathologies, including cancer, the ECM is exposed due to increased endothelial cell permeability. NP conjugated with ligands targeted to extracellular matrix (ECM) binding sites can achieve selective and safe drug delivery for cancer

Subendothelial low-density lipoproteins (LDL) retention through proteoglycan interaction is enhanced in diseases of enhanced endothelial permeability, including cancer. We hypothesized that a peptide shared by apo-B100 (25 AA), the LDL protein moiety, would effectively bind proteoglycans. In vitro studies identified amino acid sequences in delipidated apo-B100, which bind to negatively charged proteoglycans. We have synthesized lipid and polymeric conjugates with the apo-B peptide ligand for high ECM affinity. siRNA against FGFR1 and OPN was encapsulated in polymeric NP (poly(d,l-lactide co-glycolide (PLGA)) and core-shell type liposomes, decorated with the apo-B ligand via a poly(ethylene glycol) (PEG) spacer. Results show that the siRNA was effectively encapsulated in the NP (< 150 nm), using a double emulsion system or a liposome-lipoplex complex for formulating polymeric NP and core-shell liposomes, respectively. The uptake of the targeted NP was examined in cell and ECM cultures assisted by fluorescent labeling of the formulations (BODIPY). Flow cytometry (FACS) studies showed effective uptake in rat primary smooth muscle cells that naturally shed proteoglycans. The in vivo therapeutic effect was examined in a murine model of mammary carcinoma. It is concluded that siRNA can be effectively encapsulated in biocompatible and biodegradable targeted NP, and the siRNA is stable and bioactive in mammary carcinoma animal model.

Convection Enhanced Delivery of Liposomes to the Brain

Convection-enhanced drug delivery (CED) greatly enhances the distribution of drugs in the brain by creating an infusion-mediated pressure gradient through intracranial catheters. This technique enables in situ drug concentrations several orders of magnitude greater than those achieved by systemic administration over large brain volumes. Gd-DTPA is a Magnetic Resonance Imaging (MRI) contrast agent that can be infused by CED into brain tissue. Since Gd-based contrast agents do not penetrate the cells, follow-up MRI performed 24 hours post treatment shows no residual Gd in the brain. In the current study we assessed the feasibility of using PEGylated and nonPEGylated liposomes to obtain increased cell internalization of therapeutic agents delivered by CED in rats. Feasibility was demonstrated by liposomes loaded with Gd-DTPA. PEGylated and nonPEGylated liposomes contained similar Gd-DTPA concentration. Their signal intensity following incubation with cancer cells was significantly higher than that of empty PEGylated liposomes treated cells. All groups showed enhancement in T1 MRI immediately after CED. After 2 days there was no noticeable residual Gd-DTPA in the brains of rats treated with Gd-DTPA in saline. In contrast, enhancement was noticed even 2 weeks after treatment with PEGylated and NonPEGylated Gd liposomes. The volume of distribution of the PEGylated liposomes in the brain was nearly twice than that of the nonPEGylated liposomes.

Specific research topics related to Nanoscience and Nanotechnology:

• Targeted nanoparticles of siRNA for mammary carcinoma therapy.
• Immunomodulation and anti-inflammatory effects by nanoparticles in restenosis and myocardial infarction.
• Immunomodulation by liposomes for endometriosis therapy.
• Delivery of nanoparticles to the brain.

List of publications in Nanoscience and Nanotechnology (2010-2011)

• J.M. Chan, J. Rhee, C.L. Drum, R.T. Bronson, G. Golomb, R. Langer and O.C. Farokhzad, In vivo prevention of arterial restenosis with paclitaxel-encapsulated targeted lipid-polymeric nanoparticles, Proc. Natl. Acad. Sci. USA, 108, 19347-19352 (2011).
• D. Gutman, H. Epstein-Barash, M. Tsuriel and G. Golomb, Alendronate liposomes for antitumor therapy: Activation of gamma/delta T cells and inhibition of tumor growth, Adv. Exp. Med. Biol. 733, 165-79 (2012).
• C. Reufsteck, R. Lifshitz-Shovali, M. Zepp, T. B?uerle, D. K?bler, G. Golomb and M.R. Berger, Silencing of skeletal metastasis-associated genes impairs migration of breast cancer cells and reduces osteolytic bone lesions, Clin. Exp. Metastasis, 29, 441-456 (2012).
• M. Zepp, T.J. B?uerle, V. Elazar, J. Peterschmitt, R. Lifshitz-Shovali, H. Adwan, F.P. Armbruster, G. Golomb and M.R. Berger, Treatment of breast cancer lytic skeletal metastasis using a model in nude rats. In: Breast Cancer - Current and Alternative Therapeutic Modalities, E. Gunduz and M. Gunduz Eds., InTech Open Access Books, 2011, pp. 453-488.
• D. Gutman and G. Golomb, Liposomal alendronate for the treatment of restenosis, J. Control. Release 161, 619?627 (2012).

Patents (2011-12):

Cooperation with other researchers/universities

• Drexel University, Mechanical Engineering, Philadelphia, PA, USA (Prof. A. Morss Clyne)
• Unit of Chemotherapy and Toxicology, German Cancer Research Center (DKFZ), Heidelberg, Germany (Prof. M. Berger).
• Prof. Y. Mardor, Sackler Faculty of Medicine, Tel Aviv University; The Advanced Technology Center, Sheba Medical Center.
• Prof. U. Banin, Nanocenter, HUJI.

Students, postdocs and researchers (include those graduated in 2008-2009):

Ph.D. students: Einat Cohn-Sela (2011), Eyal Afergan (2011), Dikla Gutman (2012), Elran Haber (2012), Meital Naim.
M.Sc. students: R. Mirkin (graduated 2012), M. Tzuriel, K. Zolotevrsky, K. Magidey (with Prof. Danenberg), Roni Yaffe (with Y. Mardor, TAU), Gil Aizik.

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