title: Identification of differentially expressed genes in metastatic and non-metastatic nasopharyngeal carcinoma cells by suppression subtractive hybridization.
abstract: OBJECTIVE
  Nasopharyngeal carcinoma (NPC) is an epithelial neoplasm with high occurrence rates in southern China. The disease often metastasizes to regional lymphnodes at a very early stage. Local recurrences and metastasis occur frequently in patients with NPC and are a leading cause of death, despite improvements on treatment modalities. The molecular mechanism underlying the metastasis of nasopharyngeal carcinoma remains poorly understood, however, and requires additional elucidation. The aim of this study was to explore possible NPC gene candidates that may play key roles in NPC metastasis.
  
  
  METHODS
  Subtractive suppression hybridization (SSH) was performed to isolate differentially expressed clones between the metastatic 5-8F and non-metastatic 6-10B nasopharyngeal carcinoma cell lines. Differentially expressed clones were screened and confirmed by reverse Northern blotting. The sequences of cDNA fragments were subsequently analyzed and compared to known sequences in Genbank.
  
  
  CONCLUSIONS
  The SSH library contained thousands of positive clones. Random analysis of 300 clones by PCR demonstrated that 269 clones contained inserted fragments. Reverse Northern blot confirmed that 20 out of 192 clones examined were significantly up-regulated in the 5-8F cell line. Among these 20 clones, 16 were previously identified genes (flotilin-2, ezrin, pim-3, fli-1, mel, neugrin, znf216, ASB1, raly, UBE2A, keratin6A, TMED7, EIF3S9, FTL, two ribosomal proteins RPL21 and RPL16), two were predicted genes (c9orf74 and MDS006), and two sequences shared no homology with known genes listed in GenBank and may represent novel genes. The proposed functions of the genes identified in this study include cell signal transduction, cell survival, transcription regulation, cell mobility, protein synthesis, and DNA damage repair. Flotillin-2, fli-1, pim-3 and ezrin have previously been reported to be associated with tumor metastasis and progression. The remaining up-regulated genes identified in this study have not been reported to be markers of metastasis and may represent new candidates of NPC metastasis-related genes. The results of this study may provide novel points of therapeutic intervention for NPC.
authors.affiliation: Cancer Research Institute of Central South University, Changsha, Hunan 410078, PR China.
authors.forename: Xu-Yu
authors.initials: XY
authors.lastname: Yang
authors.forename: Cai-Ping
authors.initials: CP
authors.lastname: Ren
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Chun-Jie
authors.initials: CJ
authors.lastname: Jiang
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Kai-Tai
authors.initials: KT
authors.lastname: Yao
mesh_terms: D018076:DNA, Complementary / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D015723:Gene Library; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology*; D009362:Neoplasm Metastasis / Q000235:genetics*; D009693:Nucleic Acid Hybridization / Q000379:methods*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D015252:Deoxyribonucleases, Type II Site-Specific; C040158:GTAC-specific type II deoxyribonucleases