title: Development of trastuzumab-resistant human gastric carcinoma cell lines and mechanisms of drug resistance.
abstract: Trastuzumab has been successfully employed for the treatment of Her-2-positive gastric cancer. However, there are problems with both primary and secondary resistance to trastuzumab. In this study, we employed the human gastric carcinoma cell line NCI-N87 with high Her-2 expression to create trastuzumab-resistant NCI-N87/TR cells by stepwise exposure to increasing doses of trastuzumab. Western blotting and Real-time PCR were conducted to detect protein and gene levels. Compared with NCI-N87 cells, the expression of P-IGF-1R and P-AKT proteins was significantly increased in NCI-N87/TR cells (both P = 0.000), while PTEN gene and protein expression showed a significant decrease (both P = 0.000). In addition, mutations of the PTEN gene were detected at exons 5, 7, and 8. The sensitivity of NCI-N87/TR cells to trastuzumab was increased by transfection with the PTEN gene, or by incubation with a PI3K inhibitor (LY294002) or an IGF-IR inhibitor (AG1024), as well as siRNA targeting PI3K p110 or IGF-1R. Taken together, our findings showed that activation of the PI3K-AKT signaling pathway was one of the major mechanisms leading to resistance of NCI-N87/TR gastric cancer cells to trastuzumab, which was probably associated with PTEN gene down-regulation and mutation, as well as with over-activity of the IGF-1R signaling pathway.
authors.affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zuo
authors.affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Mengwan
authors.initials: M
authors.lastname: Wu
authors.affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Lihong
authors.initials: L
authors.lastname: Guo
authors.affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Wangjun
authors.initials: W
authors.lastname: Liao
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002867:Chromones / Q000494:pharmacology; D058543:Class Ia Phosphatidylinositol 3-Kinase / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000068878:Trastuzumab / Q000494:pharmacology*; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D020032:Tyrphostins; C447031:tyrphostin AG 1024; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D058543:Class Ia Phosphatidylinositol 3-Kinase; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; D000068878:Trastuzumab