Nucleic acids biosensors for the early detection of tumorigenic lung cell lines.

B21

Functional nucleic acids, known as aptamers, can be selected from random sequence populations. Aptamers can potentially be applied in conventional roles for identifying and typing tumors, essentially as substitutes for antibodies or other staining reagents. Fluorescent aptamers have been used to label cells in flow cytometry. A 2â™-fluoropyrimidine modified RNA pool that contains a random sequence core of 30 nucleotides flanked by primer binding sites has been generated and selected against three lung tumor cell lines that differ in their Epidermal Growth Factor Receptor (EGFR) expression were chosen as targets for selection. NCI-H358 is from a non-small cell lung cancer and expresses wild type EGFR. NCI-1650 is from a bronchoalveolar carcinoma and expresses a mutant form of EGFR (in-frame deletion delE746-A750). NCIH526 is from a small cell lung cancer (SCLC) cell lines and expresses low to undetectable levels of EGFR. Selection of aptamers against these three lines serves several purposes: first, it will potentially demonstrate that aptamers against cell surfaces can be used to differentiate different types of lung tumor cells as well as typing tumor cells from normal cells. These aptamers can further be modified for early detection of tumorigenic cells. Second, aptamers may be derived that recognize particular types or levels of EGFR, an important tumor marker. Finally, selection methods that target both adherent and suspension cells will be developed.