[Effects of RNA interference on epidermal growth factor receptor expression in SPC-A-1 cells].
OBJECTIVE
To investigate whether RNA interference (RNAi) induced by small interference RNA (siRNA) could suppress epidermal growth factor receptor (EGFR) expression in non-small-cell lung carcinoma (NSCLC) cells.


METHODS
SPC-A-1 cells were transfected using chemically synthesized double stranded RNA (dsRNA) formulated with Lipofectamine 2000. The EGFR numbers were determined by both Western blot and flow cytometry. The antiproliferative effects of dsRNA-EGFR were assessed using cell counts and colony assay. Cell cycle analysis was carried out via flow cytometry. The chemosensitivity of transfected cells to cisplatin was determined by MTT.


RESULTS
Sequence specific siRNAs targeting EGFR down-regulated EGFR expression significantly. Compared with the control group, dsRNA-EGFR reduced the cell numbers by 78.3% and decreased the colonies by 66.8%. Cell cycle analysis showed that dsRNA-EGFR induced accumulation of cells in G0-G1 phase by 17.48% with a significant decrease in the percentage of cells in S-phase by 19.20% relative to the control. Based on the value of IC50 obtained by Origin 6.0 software, we concluded that dsRNA-EGFR increased the sensitivity of SPC-A-1 to cisplatin by seven-fold.


CONCLUSIONS
Sequence specific siRNAs targeting EGFR was capable of suppressing EGFR expression, and therefore, significantly inhibiting cellular proliferation and inducing cell cycle arrest. The finding from chemosensitivity assay further revealed that dsRNA-EGFR was associated with an addictive or synergistic effect on tumor growth inhibition when combined with cisplatin. The successful application of dsRNA-EGFR for inhibition of proliferation in EGFR overexpressing cells extends the list of available therapeutic modalities in the treatment of human cancer.
Zhang
Min
M
Institute of Respiratory Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
Zhang
Xin
X
Bai
Chun-xue
CX
Chen
Jie
J
Wei
MinQ
M
D000970:Antineoplastic Agents / Q000494:pharmacology; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D014162:Transfection
D000970:Antineoplastic Agents; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D066246:ErbB Receptors; D002945:Cisplatin