title: Recurrent Amplification at 13q34 Targets at CUL4A, IRS2, and TFDP1 As an Independent Adverse Prognosticator in Intrahepatic Cholangiocarcinoma.
abstract: Amplification of genes at 13q34 has been reported to be associated with tumor proliferation and progression in diverse types of cancers. However, its role in intrahepatic cholangiocarcinoma (iCCA) has yet to be explored. We examined two iCCA cell lines and 86 cases of intrahepatic cholangiocarcinoma to analyze copy number of three target genes, including cullin 4A (CUL4A), insulin receptor substrate 2 (IRS2), and transcription factor Dp-1 (TFDP1) at 13q34 by quantitative real-time polymerase chain reaction. The cell lines and all tumor samples were used to test the relationship between copy number (CN) alterations and protein expression by western blotting and immunohistochemical assays, respectively. IRS2 was introduced, and each target gene was silenced in cell lines. The mobility potential of cells was compared in the basal condition and after manipulation using cell migration and invasion assays. CN alterations correlated with protein expression levels. The SNU1079 cell line containing deletions of the target genes demonstrated decreased protein expression levels and significantly lower numbers of migratory and invasive cells, as opposed to the RBE cell line, which does not contain CN alterations. Overexpression of IRS2 by introducing IRS2 in SUN1079 cells increased the mobility potential. In contrast, silencing each target gene showed a trend or statistical significance toward inhibition of migratory and invasive capacities in RBE cells. In tumor samples, the amplification of each of these genes was associated with poor disease-free survival. Twelve cases (13.9%) demonstrated copy numbers > 4 for all three genes tested (CUL4A, IRS2, and TFDP1), and showed a significant difference in disease-free survival by both univariate and multivariate survival analyses (hazard ratio, 2.69; 95% confidence interval, 1.23 to 5.88; P = 0.013). Our data demonstrate that amplification of genes at 13q34 plays an oncogenic role in iCCA featuring adverse disease-free survival, which may provide new directions for targeted therapy.
authors.affiliation: Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.|Department of laboratory Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Liu
authors.affiliation: Department of laboratory Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.|Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan.
authors.forename: Huey-Ling
authors.initials: HL
authors.lastname: You
authors.affiliation: Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Shao-Wen
authors.initials: SW
authors.lastname: Weng
authors.affiliation: Department of Pathology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Wei
authors.affiliation: Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Hock-Liew
authors.initials: HL
authors.lastname: Eng
authors.affiliation: Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.|Department of laboratory Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Wan-Ting
authors.initials: WT
authors.lastname: Huang
mesh_terms: D001650:Bile Duct Neoplasms / Q000235:genetics* / Q000401:mortality; D045744:Cell Line, Tumor; D002465:Cell Movement; D018281:Cholangiocarcinoma / Q000235:genetics* / Q000401:mortality; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D044842:Cullin Proteins / Q000235:genetics*; D056915:DNA Copy Number Variations; D018572:Disease-Free Survival; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D020440:Gene Duplication; D006801:Humans; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D050680:Transcription Factor DP1 / Q000235:genetics*
chemical_list: C114234:CUL4A protein, human; D044842:Cullin Proteins; C526297:IRS2 protein, human; D055504:Insulin Receptor Substrate Proteins; C493735:TFDP1 protein, human; D050680:Transcription Factor DP1