Characterization of somatostatin receptor expression in human pancreatic cancer using real-time RT-PCR

J Surg Res. 2004 Jun 15;119(2):130-7. doi: 10.1016/j.jss.2004.03.006.


Background: Somatostatin inhibits cell proliferation and may act as a tumor suppressor by interacting with five different somatostatin receptors (SSTRs). We hypothesized that SSTR expression is down-regulated in human pancreatic cancer. In the current study, we used a powerful real-time RT-PCR technique to examine the mRNA expression levels of all five SSTR subtypes in human pancreatic cancer.

Materials and methods: Total RNA was extracted from three pancreatic cancer cell lines (Panc-1, MIA PaCa-2, and Hs 766T), three surgical specimens of pancreatic cancer, and adjacent pancreatic tissue, and a pancreatic cancer cell line transfected with the SSTR-2 gene. Specific primers were designed and mRNA levels for the five SSTRs were analyzed with real-time quantitative RT-PCR using a Bio-Rad iCycler system.

Results: The pancreatic tumor specimens had a 2.5- and 4.3-fold reduction of SSTR-2 and SSTR-5 mRNA levels, respectively, as compared to their adjacent normal pancreatic tissues. SSTR-1 and SSTR-3 were also detected in both the cancer specimens and the adjacent tissues, but SSTR-4 was absent. Human pancreatic cancer cell lines also expressed SSTR-2 and SSTR-5 mRNA, but not SSTR-1, SSTR-3, and SSTR-4. Up-regulation of SSTR-2 mRNA by 2.2 x 10(4)-fold in Panc-1 cells resulted in receptor expression and growth inhibition.

Conclusion: Expression of SSTR-2 and SSTR-5 could be important in the growth inhibitory effect of somatostatin in human pancreatic cancer. Down-regulation of SSTR transcription or SSTR mRNA instability may result in loss of a tumor suppressive effect of SSTRs in human pancreatic cancer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenocarcinoma*
  • Cell Line, Tumor
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Pancreatic Neoplasms*
  • RNA, Messenger / analysis
  • Receptors, Somatostatin / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction / methods*


  • RNA, Messenger
  • Receptors, Somatostatin
  • somatostatin receptor 3
  • somatostatin receptor type 1
  • somatostatin receptor 5
  • somatostatin receptor 2