title: Genes associated with prognosis after surgery for malignant pleural mesothelioma promote tumor cell survival in vitro.
abstract: BACKGROUND
  Mesothelioma is an aggressive neoplasm with few effective treatments, one being cytoreductive surgery. We previously described a test, based on differential expression levels of four genes, to predict clinical outcome in prospectively consented mesothelioma patients after surgery. In this study, we determined whether any of these four genes could be linked to a cancer relevant phenotype.
  
  
  METHODS
  We conducted a high-throughput RNA inhibition screen to knockdown gene expression levels of the four genes comprising the test (ARHGDIA, COBLL1, PKM2, TM4SF1) in both a human lung-derived normal and a tumor cell line using three different small inhibitory RNA molecules per gene. Successful knockdown was confirmed using quantitative RT-PCR. Detection of statistically significant changes in apoptosis and mitosis was performed using immunological assays and quantified using video-assisted microscopy at a single time-point. Changes in nuclear shape, size, and numbers were used to provide additional support of initial findings. Each experiment was conducted in triplicate. Specificity was assured by requiring that at least 2 different siRNAs produced the observed change in each cell line/time-point/gene/assay combination.
  
  
  RESULTS
  Knockdown of ARHGDIA, COBLL1, and TM4SF1 resulted in 2- to 4-fold increased levels of apoptosis in normal cells (ARHGDIA only) and tumor cells (all three genes). No statistically significant changes were observed in apoptosis after knockdown of PKM2 or for mitosis after knockdown of any gene.
  
  
  CONCLUSIONS
  We provide evidence that ARHGDIA, COBLL1, and TM4SF1 are negative regulators of apoptosis in cultured tumor cells. These genes, and their related intracellular signaling pathways, may represent potential therapeutic targets in mesothelioma.
authors.affiliation: Division of Thoracic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Gordon
authors.forename: Raphael
authors.initials: R
authors.lastname: Bueno
authors.forename: David J
authors.initials: DJ
authors.lastname: Sugarbaker
mesh_terms: D000954:Antigens, Surface / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D055785:Gene Knockdown Techniques; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008654:Mesothelioma / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D008938:Mitosis / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010997:Pleural Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D034622:RNA Interference
chemical_list: D000954:Antigens, Surface; D020730:Guanine Nucleotide Dissociation Inhibitors; D009363:Neoplasm Proteins; C074075:TM4SF1 protein, human