title: Pasireotide (SOM230) is effective for the treatment of pancreatic neuroendocrine tumors (PNETs) in a multiple endocrine neoplasia type 1 (MEN1) conditional knockout mouse model.
abstract: BACKGROUND
  Pasireotide (SOM230), a long-acting somatostatin analogue (LAR), has improved agonist activity at somatostatin receptors. We tested the effect of SOM230 on insulin secretion, serum glucose concentrations, tumor growth, and survival using an MEN1 transgenic mouse model.
  
  
  METHODS
  Eight 12-month-old conditional Men1 knockout mice with insulinoma were assessed. The treatment (n = 4) and control groups (n = 4) received monthly subcutaneous injections of SOM230 or PBS. Serum insulin and glucose levels were determined by enzyme-linked immunosorbent assay and enzymatic colorimetric assay, respectively. Tumor activity, growth, and apoptosis were determined by microPET/CT scan and histologic analysis.
  
  
  RESULTS
  On day 7, there was a decrease in serum insulin levels from 1.06 ± 0.28 μg/L to 0.37 ± 0.17 μg/L (P = .0128) and a significant increase in serum glucose from 4.2 ± 0.45 mmol/L to 7.12 ± 1.06 mmol/L (P = .0075) in the treatment group but no change in the control group. Tumor size was less in the treatment group (2,098 ± 388 μm(2)) compared with the control group (7,067 ± 955 μm(2); P = .0024). Furthermore, apoptosis was increased in the treatment group (6.9 ± 1.23%) compared with the control group (0.29 ± 0.103%; P = .002).
  
  
  CONCLUSIONS
  SOM230 demonstrates antisecretory, antiproliferative, and proapoptotic activity in our MEN1 model of insulinoma. Further studies of the effects of SOM230 in PNET patients with MEN1 mutations are warranted.
authors.affiliation: Department of Surgery, Albert Einstein College of Medicine, New York, NY 10467, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Quinn
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Yuan
authors.forename: Asha
authors.initials: A
authors.lastname: Adem
authors.forename: Rula
authors.initials: R
authors.lastname: Geha
authors.forename: Chakravarthy
authors.initials: C
authors.lastname: Vrikshajanani
authors.forename: Wade
authors.initials: W
authors.lastname: Koba
authors.forename: Eugene
authors.initials: E
authors.lastname: Fine
authors.forename: David T
authors.initials: DT
authors.lastname: Hughes
authors.forename: Herbert A
authors.initials: HA
authors.lastname: Schmid
authors.forename: Steven K
authors.initials: SK
authors.lastname: Libutti
mesh_terms: D000818:Animals; D017209:Apoptosis; D001786:Blood Glucose / Q000032:analysis; D007328:Insulin / Q000097:blood; D051379:Mice; D018345:Mice, Knockout; D064847:Multimodal Imaging; D018761:Multiple Endocrine Neoplasia Type 1 / Q000188:drug therapy* / Q000235:genetics; D018358:Neuroendocrine Tumors / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D049268:Positron-Emission Tomography; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014057:Tomography, X-Ray Computed
chemical_list: D001786:Blood Glucose; D007328:Insulin; D013004:Somatostatin; C517782:pasireotide