Home Page Researchers Abraham Rubinstein

Abraham Rubinstein

School of Pharmacy
Faculty of Medicine
The Hebrew University, Jerusalem 91120, Israel
Tel: + 972-2-6758603
E-mail: avrir@ekmd.huji.ac.il

In situ luminal detection of biomarkers in the gastrointestinal (GI) fluids

Early detection was shown to improve outcome in gastrointestinal (GI) malignancies. However, cancer screening is based mainly on endoscopic procedures combined with histopathological examination of biopsied tissue and fecal occult blood testing followed by fibro-optic colonoscopy with biopsy. Serum biomarkers, such as glycoprotein carcinoembryonic antigen (CEA) are mainly used for follow up purposes and has no role in cancer diagnosis or screening. The ability to sample and identify secreted cancer-specific biomarkers in GI luminal fluids may significantly reduce the cost and the time interval for the diagnosis of GI malignancies.

Employing model biomarker molecules such as ?1-antitrypsin precursor, hemoglobin, CEA and carbohydrate antigen 19-9 (CA 19-9, also known as sialylated Lewis (a) antigen) we developed and explored a composite platform, comprised of a transparent solid support grafted with capturing moieties, capable of immobilizing biomarker molecules and erodible gel matrices loaded with fluorescent immuno-nanoparticles. The fluorescent nanoparticles (at the NIR range) were decorated, separately, with relevant antibodies to each biomarker molecule. They were then loaded into a specially designed matrix that, upon controlled erosion by the fluids if the GI tract, provided a constant input (pseudo-zero order rate) of the immuno nanoparticles on the surface of the immobilized biomarker molecules. A local, specific, illumination was then developed and detected by a bench simulator of a video pill (a remote endoscopic device), at a typical sensitivity of endoscopic device, commonly used in the clinic.

Targeting the inflamed mucosa of the GI tract by immunoliposomes

Upon activation of immune cells, transferrin receptor (TfR) expression increases at their surface. Because TfR is expressed in all cell types we hypothesized that its cell surface levels are regulated also in enterocytes. TfR expression was elevated in the colonic mucosa of IBD patients in both the basolateral and apical membranes of the enterocytes. Increased TfR expression was also observed in colonocytes of the induced colitis rats. To explore the underlying mechanism CaCo-2 cells were treated with various proinflammatory cytokines, which increased both TfR expression and transferrin cellular uptake in a mechanism that did not involve hyper proliferation. These findings were then exploited for the design of targetable carrier towards inflamed regions of the colon. Anti-TfR antibodies were conjugated to nano-liposomes. As expected, iron-starved Caco-2 cells internalized anti-TfR immunoliposomes better than controls. Ex vivo binding studies to inflamed mucosa showed that the anti-TfR immunoliposomes accumulated significantly better in the mucosa of DNBS-induced rats than the accumulation of non-specific immunoliposomes.

It was concluded that targeting mucosal inflammation can be accomplished by nano-liposomes decorated with anti-TfR due to inflammation-dependent, apical, elevated expression of the receptor.

Specific research topics related to Nanoscience and Nanotechnology:

  • Real-time diagnosis of GI malignancies by nano/photonic tools at the mucosa and cellular levels.
  • Targeting the inflamed mucosa of the GI tract by (nano) immunoluiposomes.

List of Publications (2010-2012):

  • Cohen S., Grinberg I., Kam Y., Corem-Salkmon E., Rubinstein A. and Margel S. Synthesis and characterization of near IR fluorescent albumin nanoparticles for optical detection of colon cancer. Mater. Sci. Engineer. C, 2012, in press.
  • Kam Y., Rubinstein A., Nissan A., Halle D. and Yavin E. Detection of endogenous k-RAS mRNA in living cells at a single base resolution by a PNA molecular beacon. Molecular Pharm, 9: 685-693, 2012.
  • Khazanov E., Yavin E., Pascal A., Nissan A., Kohl Y., Reimann-Zawadzki M., and Rubinstein A. Detecting a secreted gastric cancer biomarker molecule by targeted nanoparticles for real-time diagnostics. Phram. Res. 29: 983-993, 2012.
  • Harel E., Rubinstein A., Nissan A., Khazanov E., Nadler-Milbauer M., Barenholz Y. and Tirosh B. Enhanced transferrin receptor expression by proinflammatory cytokines in enterocytes as a means for local delivery of drugs to inflamed gut mucosa. PLoS ONE, 6(9): e24202, 2011.

Significant in the last five years

  • Khazanov E., Emmanuel N., Azab A.K., Barenholz Y., Yavin E. and Rubinstein A.
    Specific detection of gastric a-antitrypsin by immobilized trypsin on polyHEMA films., Molecular Pharm., 7: 944-952, 2010.
  • Azab A. K., Kleinstern J., Srebnik M. and Rubinstein A.
    The metastatic stage-dependent mucosal expression of sialic acid is a potential marker for targeting colon cancer with cationic polymers., Pharm. Res., 25: 379-386, 2008.
  • Haupt S., Zioni T., Gati I., Kleinstern J., and Rubinstein A.
    Luminal delivery and dosing considerations of local celecoxib administration to colorectal cancer., Eur. J. Pharm. Sci., 28: 204-211, 2006.

Cooperation wih industries and defense projects (2009-2010):

Collaboration with other researchers/universities in Israel:

Within Hebrew University:
  • Professor Chezy Barenholz, The Hebrew University of Jerusalem, Faculty of Medicine, Laboratory of Membrane and Liposome Research.
  • Dr. Eylon Yavin, The Hebrew University of Jerusalem, Faculty of Medicine, The School of Pharmacy Institute for Drug Research.
  • Dr. Aviram Nissan, Surgical Oncology Laboratory, Department of Surgery, Hadassah - Hebrew University Medical Center, Mount Scopus.

Students, postdocs and researchers :

Research associate: Dr. Elena Khazanov
Ph.D. students:

  1. Meital Bloch: Real-time detection of GI malignancy by multifunctional micro bubbles loaded with targeted, polymeric tag. 2011 - present.
  2. Dorit Moradov: Novel ?-carbonylboronates protease inhibitors for mucosal delivery of protein drugs. 2006 - present.
  3. Yossi Kam: Biomedical Photonics for real time diagnostics of colon adenomas. 2007- present.
  4. Helena Shifrin: Combinatorial IBD therapy with cholinesterase inhibitors and steroid drugs. 2009 - present.
  5. Efrat Harel: Mucosal treatment of necrotizing enterocolitis with novel boronated metaloprotease inhibitors. 2006 - present.
  6. Mirela Nadler-Milbauer: Local treatment of colonic inflammation with targeted liposomal antiinflammatory drugs. 2006 - 2011.

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