Inhibition of lung adenocarcinoma cells by insulin-like growth factor-I receptor and Kirsten rat sarcoma mutations: A mutation analysis with antisense oligodeoxynucleotide

BACKGROUND Kirsten rat sarcoma (KRAS) mutations are widespread in lung adenocarcinoma patients. The combined utilization of KRAS antisense oligodeoxynucleotide (ASODN) and insulin-like growth factor-I receptor (IGF-IR) may inhibit the proliferation of A549 cell lines of lung adenocarcinoma. METHODS Point mutations of the KRAS gene in A549 cells were detected by polymerase chain reaction with special sequence primers (PCR-SSP) and gene sequence analysis; ASODN was designed and synthesized according to the mutation specialty of KRAS; and the correlation of gene mutations and clinicopathological features were analyzed. Inhibition on the proliferation and morphostructure change were measured by methyl thiazolyl tetrazolium and colony-forming unit assays. Flow cytometry was used to evaluate the expression of KRAS and IGF-IR proteins and cell apoptosis and reverse transcriptase-polymerase chain reaction were used to detect the expression of KRAS and IGF-IR messenger ribonucleic acid (mRNA). Male nude mice were used to form the mice-human lung cancer model and show the inhibition of KRAS ASODN on A549 cells. RESULTS PCR-SSP and gene sequence analysis results showed that the codon 12 of KRAS had changed from GGT to GTT. KRAS ASODN or IGF-IR ASODN could inhibit cell proliferation and promote apoptosis of A549 cells. However, the combined utilization of KRAS ASODN and IGF-IR ASODN could inhibit cell proliferation and promote apoptosis more powerfully than exclusive use of KRAS ASODN or IGF-IR ASODN. CONCLUSION The two ASODNs can inhibit the proliferation of lung adenocarcinoma cells through decreasing the expression of KRAS and IGF-IR mRNA and protein.