title: Conjugate-SELEX: A High-throughput Screening of Thioaptamer-liposomal Nanoparticle Conjugates for Targeted Intracellular Delivery of Anticancer Drugs.
abstract: Patients with advanced head and neck squamous cell carcinoma receiving chemotherapy have a poor prognosis partly due to normal tissue toxicity; therefore, development of a tumor-targeted drug delivery platform to minimize collateral toxicity is a goal of cancer nanomedicine. Aptamers can achieve this purpose. While conventional Systematic Evolution of Ligands by Exponential Enrichment (SELEX) screens aptamer-only libraries and conjugates them to delivery vehicles after selection, we hypothesized that specific delivery requires screening libraries with aptamer-nanoparticle conjugates. We designed a procedure called, "Conjugate-SELEX", where liposomal nanoparticles (LNP) conjugated with aptamers is screened to identify aptamers that carried attached LNPs to the human head and neck squamous cell carcinoma cell cytosol. Aptamer-LNPs were simultaneously selected for a low affinity to human hepatocytes, minimizing hepatoxicity and LNP clearance. Post-SELEX Next Generation sequencing demonstrated convergence to a family of sequences with one base difference. Affinity pulldown and proteomics analysis identified the uptake-mediating surface receptor as the neuroblast differentiation-associated protein AHNAK (Desmoyokin), a ubiquitous intracellular protein expressed in certain epithelial cell types. Uptake studies with the lead aptamer-conjugates showed enhanced uptake and increased cytotoxicity induced by doxorubicin in cells treated with aptamer-conjugated LNPs over LNP controls. Conjugate-SELEX identifies aptamers capable of targeted cytosolic delivery of attached LNPs payload, while minimizing off-target delivery. The technique lends itself to identification of uptake-mediating surface receptors.
authors: Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas, USA.
authors: Qingshan
authors: Q
authors: Mu
authors: Debakey High School, Houston, Texas, USA.
authors: Akshaya
authors: A
authors: Annapragada
authors: The Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston, Texas, USA.
authors: Mayank
authors: M
authors: Srivastava
authors: Department of Nanomedicine and Biomedical Engineering, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors: Xin
authors: X
authors: Li
authors: Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas, USA.
authors: Jean
authors: J
authors: Wu
authors: Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas, USA.|Department of Nanomedicine and Biomedical Engineering, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors: Varatharasa
authors: V
authors: Thiviyanathan
authors: Department of Nanomedicine and Biomedical Engineering, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors: Hongyu
authors: H
authors: Wang
authors: Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas, USA.
authors: Alexander
authors: A
authors: Williams
authors: Department of Nanomedicine and Biomedical Engineering, University of Texas Health Science Center at Houston, Houston, Texas, USA.
authors: David
authors: D
authors: Gorenstein
authors: The Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston, Texas, USA.
authors: Ananth
authors: A
authors: Annapragada
authors: Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas, USA.
authors: Nadarajah
authors: N
authors: Vigneswaran