Tenascin-C aptamers are generated using tumor cells and purified protein.
Tenascin-C (TN-C) is an extracellular matrix protein that is overexpressed during tissue remodeling processes, including tumor growth. To identify an aptamer for testing as a tumor-selective ligand, SELEX (systematic evolution of ligands by exponential enrichment) procedures were performed using both TN-C and TN-C-expressing U251 glioblastoma cells. The different selection techniques yielded TN-C aptamers that are related in sequence. In addition, a crossover procedure that switched from tumor cell to purified protein selections was effective in isolating two high-affinity TN-C aptamers. When targeting tumor cells in vitro, the observed propensity of naive oligonucleotide pools to evolve TN-C aptamers may be due to the abundance of this protein. In vivo, TN-C abundance may also be well suited for aptamer accumulation in the tumor milieu. A size-minimized and nuclease-stabilized aptamer, TTA1, binds to the fibrinogen-like domain of TN-C with an equilibrium dissociation constant (K(d)) of 5 x 10(-9) m. At 13 kDa, this aptamer is intermediate in size between peptides and single chain antibody fragments, both of which are superior to antibodies for tumor targeting because of their smaller size. TTA1 defines a new class of ligands that are intended for targeted delivery of radioisotopes or chemical agents to diseased tissues.
Hicke
B J
BJ
SomaLogic, Boulder, Colorado 80301, USA. bhicke@somalogic.com
Marion
C
C
Chang
Y F
YF
Gould
T
T
Lynott
C K
CK
Parma
D
D
Schmidt
P G
PG
Warren
S
S
D000818:Animals; D005109:Extracellular Matrix / Q000737:chemistry; D005909:Glioblastoma / Q000378:metabolism; D006801:Humans; D008024:Ligands; D051379:Mice; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D020349:Surface Plasmon Resonance; D019063:Tenascin / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D008024:Ligands; D009841:Oligonucleotides; D010446:Peptide Fragments; D019063:Tenascin