Objective： Her-2/neu protein overexpression has been demonstrated in lung adenocarcinoma. Its overexpression often indicates a poor prognosis and resistance to chemotherapeutic agents. The objectives of this paper is to explore the effectiveness of double-stranded short inhibitory RNAs （siRNA） targeting Her-2/neu oncogene on the drug sensitivity of Her-2/neu-overexpressing lung adenocarcinoma cells. Methods： Lung adenocarcinoma cell line calu-3 was transfected with siRNAs formulated LipofectAMINE 2000, and Her-2/neu protein and P-gp were determined by flow cytometry （FCM）. The chemosensitivity of transfected cells to cisplatin （CDDP） was measured by MTT. Cell apoptosis detection kit （Annexin V method） was used to examine the drug induced apoptosis rate. Results： siRNA targeting Her-2/neu greatly reduced the cell surface expression of Her-2/neu protein and had no effect on P-gp. Consequently the inhibitory rate of CDDP in combination with siRNA targeting Her-2/neu was （67.1±2.3）%, while the inhibitory rates were （48.1±3.5）%, （46.3±5.9）% and （50.2±2.9）% in untreated control, empty vector and unrelated siRNA groups, respectively. The FCM results showed that the apoptosis rate of cells treated with CDDP combined with siRNAs-Her-2/neu was elevated when compared with unrelated siRNA group and empty vector group. Conclusion： Sequence specific siRNA targeting Her-2/neu was capable of enhancing the chemosensitivity of calu-3 cell to cisplatin.
Objective: Her-2/neu protein overexpression has been demonstrated in Non-small cell lung cancer, especially in lung adenocarcinoma. Its overexpression often indicates a poor prognosis. Therapeutic agents against her-2/neu have been intensively sought over the past decades. The objective of this paper is to investigate the effect of chemically synthesized siRNA targeting her-2/neu on her-2/neu dysregulated human lung adenocarcinoma cells. Methods: Calu-3 cells were transfected with siRNAs formulated LipofectAMINE 2000. The her-2/neu mRNA and protein levels were detected by RT-PCR and flow cytometry (FCM). The biological morphology and growth inhibition of calu-3 cells were observed with light microscopy and MTT assay, respectively. The cell cycle and apoptosis rate were analyzed by FCM. Results: siRNA targeting Her-2/neu down-regulated the transcription of her-2/neu oncogene and protein level. Slowed cell proliferation and cell cycle arrest at G0/1 stage could be also observed, accompanied with enhanced cell apoptosis. Conclusion: Specific siRNA targeting her-2/neu can effectively inhibit her-2/neu expression in her-2/neu overexpressing calu-3 cell lines. siRNA-mediated gene silencing may be a useful therapeutic strategy for cancer.
Objective： To investigate the mechanism of carcinogenesis, invasion and metastasis. Methods： The expressions of adhesive molecule and adhesive structure in v-k-ras transformed normal rat kidney cells （KNRK） were detected with a variety of molecular biological techniques, including cell culture, immunofluorescence labeling, electron microscopy, polyacrylamide gel electrophoresis, and protein blotting, and compared with normal rat kidney （NRK） cells. Results： The significantly shortened doubling time, remarkably active proliferation ability in soft agar, and invasive growth in the abdomen of nude rat, demonstrated the malignant biological behaviors of KNRK cells. In KNRK cells, the adhesive molecules, P-cadherin, α and β catenin, actin, and adhesive structures, the adhesive junction and gap junction, were all abnormally expressed. And cell aggregation was significantly decreased. The aggregation ability disappeared at 20℃, and became active with a suitable amount of calcium solution. Conclusion： Following the transfection of virus K-ras gene, normal cells were transformed into malignant cells. In early stage of cancer, the variation of adhesive ability may be one of the vital factors underlying tumorigenesis, invasion and metastasis.
