title: Detection of neuroendocrine tumors using promoter-specific secreted Gaussia luciferase.
abstract: Accurate detection of neuroendocrine (NE) tumors is critically important for better prognosis and treatment outcomes in patients. To demonstrate the efficacy of using an adenoviral vector for the detection of NE tumors, we have constructed a pair of adenoviral vectors which, in combination, can conditionally replicate and release Gaussia luciferase into the circulation after infecting the NE tumors. The expression of these two vectors is regulated upstream by an INSM1-promoter (insulinoma-associated-1) that is specifically active in NE tumors and developing NE tissues, but silenced in normal adult tissues. In order to retain the tumor-specificity of the INSM1 promoter, we have modified the promoter using the core insulator sequence from the chicken β-globin HS4 insulator and the neuronal restrictive silencing element (NRSE). This modified INSM1-promoter can retain NE tumor specificity in an adenoviral construct while driving a mutated adenovirus E1A gene (∆24E1A), the Metridia, or Gaussia luciferase gene. The in vitro cell line and mouse xenograft human tumor studies revealed the NE specificity of the INSM1-promoter in NE lung cancer, neuroblastoma, medulloblastoma, retinoblastoma, and insulinoma. When we combined the INSM1-promoter driven Gaussia luciferase with ∆24E1A, the co-infected NE tumor secreted higher levels of Gaussia luciferase as compared to the INSM1p-Gaussia virus alone. In a mouse subcutaneous xenograft tumor model, the combination viruses secreted detectable level of Gaussia luciferase after infecting an INSM1-positive NE lung tumor for ≥12 days. Therefore, the INSM1-promoter specific conditional replicating adenovirus represents a sensitive diagnostic tool to aid clinicians in the detection of NE tumors.
authors.affiliation: The Research Institute for Children, Children's Hospital, New Orleans, LA 70118, USA.
authors.forename: Alan Wei-Shun
authors.initials: AW
authors.lastname: Tseng
authors.affiliation: The Research Institute for Children, Children's Hospital, New Orleans, LA 70118, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Akerstrom
authors.affiliation: The Research Institute for Children, Children's Hospital, New Orleans, LA 70118, USA.
authors.forename: Chiachen
authors.initials: C
authors.lastname: Chen
authors.affiliation: The Research Institute for Children, Children's Hospital, New Orleans, LA 70118, USA.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Breslin
authors.affiliation: The Research Institute for Children, Children's Hospital, New Orleans, LA 70118, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lan
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D018278:Carcinoma, Neuroendocrine; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics*
chemical_list: D012097:Repressor Proteins; C087342:INSM1 protein, human; D008156:Luciferases