title: Target-specific delivery of doxorubicin to retinoblastoma using epithelial cell adhesion molecule aptamer.
abstract: OBJECTIVE
  To study target-specific delivery of doxorubicin (Dox) using an RNA aptamer against epithelial cell adhesion molecule (EpCAM) in retinoblastoma (RB) cells.
  
  
  METHODS
  The binding affinity of the EpCAM aptamer to RB primary tumor cells, Y79 and WERI-Rb1 cells, and Müller glial cell lines were evaluated with flow cytometry. Formation of physical conjugates of aptamer and Dox was monitored with spectrofluorimetry. Cellular uptake of aptamer-Dox conjugates was monitored through fluorescent microscopy. Drug efficacy was monitored with cell proliferation assay.
  
  
  RESULTS
  The EpCAM aptamer (EpDT3) but not the scrambled aptamer (Scr-EpDT3) bound to RB tumor cells, the Y79 and WERI-Rb1 cells. However, the EpCAM aptamer and the scrambled aptamer did not bind to the noncancerous Müller glial cells. The chimeric EpCAM aptamer Dox conjugate (EpDT3-Dox) and the scrambled aptamer Dox conjugate (Scr-EpDT3-Dox) were synthesized and tested on the Y79, WERI-Rb1, and Müller glial cells. The targeted uptake of the EpDT3-Dox aptamer caused cytotoxicity in the Y79 and WERI-Rb1 cells but not in the Müller glial cells. There was no significant binding or consequent cytotoxicity by the Scr-EpDT3-Dox in either cell line. The EpCAM aptamer alone did not cause cytotoxicity in either cell line.
  
  
  CONCLUSIONS
  The results show that the EpCAM aptamer-Dox conjugate can selectively deliver the drug to the RB cells there by inhibiting cellular proliferation and not to the noncancerous Müller glial cells. As EpCAM is a cancer stem cell marker, this aptamer-based targeted drug delivery will prevent the undesired effects of non-specific drug activity and will kill cancer stem cells precisely in RB.
authors.affiliation: Larsen & Toubro Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Nithya
authors.initials: N
authors.lastname: Subramanian
authors.forename: Vaishnavi
authors.initials: V
authors.lastname: Raghunathan
authors.forename: Jagat R
authors.initials: JR
authors.lastname: Kanwar
authors.forename: Rupinder K
authors.initials: RK
authors.lastname: Kanwar
authors.forename: Sailaja V
authors.initials: SV
authors.lastname: Elchuri
authors.forename: Vikas
authors.initials: V
authors.lastname: Khetan
authors.forename: Subramanian
authors.initials: S
authors.lastname: Krishnakumar
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000737:chemistry / Q000494:pharmacology*; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001692:Biological Transport; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D000071858:Epithelial Cell Adhesion Molecule; D005434:Flow Cytometry; D015870:Gene Expression; D006801:Humans; D058990:Molecular Targeted Therapy; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009928:Organ Specificity; D011485:Protein Binding; D019572:Retinal Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D012175:Retinoblastoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D013050:Spectrometry, Fluorescence
chemical_list: D000903:Antibiotics, Antineoplastic; D000951:Antigens, Neoplasm; D052157:Aptamers, Nucleotide; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; D004337:Drug Carriers; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D004317:Doxorubicin