Antisense gene therapy using anti-k-ras and antitelomerase oligonucleotides in colorectal cancer.
OBJECTIVE
To test the efficacy of anti-k-ras and antitelomerase oligonucleotides for disabling colorectal cancer cell growth.


METHODS
An established human colorectal cancer cell line (SW 480, ATTC) was used. Oligodeoxiribonucleotides (ODNs) have a phosphorotioate modification to ensure intracellular intake. We used an antitelomerase ODN (Telp5) and two anti-k-ras ODNs (AS-KRAS and ISIS). AS-KRAS is designed to join the k-ras oncogene s exon 1. ISIS links to the terminal transcription unit 5 of k-ras. Telp5 joins the template region of the hTR telomerase subunit. ODNs have been tested in different concentrations (1, 5, 10, 20 micromolar). Cell viability has been tested at 48 and 72 hours. Statistical analysis and graphic design were made with the statistical package "Analyzing Data with GraphPad Prism-1999", GraphPad Sofware Inc., San Diego CA. We used the Student's t test for statistical analysis.


RESULTS
The lowest dose (1 microM) was not effective. Using the highest dose (20 microM for 48 hours) of combined AS-KRAS and Telp5 cell viability decreased to 99.67%. The rest of results varied depending on ODN type, dose, and exposure time.


CONCLUSIONS
Tested antisense ODNs stop colorectal cancer cell growth, and a combination of anti-telomerase and anti-k-ras is the most useful treatment. Efficacy is best with a higher dose and longer treatment period.
Lledó
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S
Department of General and Digestive Surgery, Hospital Clínico Universitario, Universidad de Valencia, Valencia, Spain. cirugia@telefonica.net
Alfonso
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R
Aliño
S F
SF
D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics / Q000628:therapy*; D011905:Genes, ras / Q000235:genetics*; D015316:Genetic Therapy; D006801:Humans; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics / Q000627:therapeutic use*; D012984:Software; D019098:Telomerase / Q000037:antagonists & inhibitors*
D020319:Oligodeoxyribonucleotides, Antisense; D019098:Telomerase