Different signal responses to lamprey GnRH-III in human cancer cells

Krisztina Herédi-Szabó, Richard F. Murphy, Sándor Lovas

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Analogs of GnRH used for the treatment of sex steroid-independent tumors are not optimal because of endocrine side-effects. Lamprey gonadotropin- releasing hormone III (lGnRH-III), however, directly inhibits the growth of several tumor cell lines derived from reproductive organs. In this study, the signaling and antiproliferative effects of lGnRH-III on two breast, a colonic and a pancreatic cancer cell lines were investigated. Binding affinity of the peptide was determined by competitive receptor binding assays. Cell proliferation was measured following treatment for 3 days with lGnRH-III. Intracellular cAMP levels in response to lGnRH-III binding were quantified and effects of pertussis toxin (PTX), an inhibitor of Gi activation, on suppression of growth by lGnRH-III were examined. lGnRH-III had comparable affinities for receptors on all four cell lines and inhibited their growth at micromolar concentrations in a dose-dependent manner. PTX-sensitive decrease in cAMP levels in response to lGnRH-III in colonic and pancreatic cells was observed, while lGnRH-III increased intracellular [Ca2+] in both breast cancer cell lines. This study further indicates that the same receptors utilize different signal transduction pathways in different cancer cells.

Original languageEnglish (US)
Pages (from-to)359-364
Number of pages6
JournalInternational Journal of Peptide Research and Therapeutics
Issue number4
StatePublished - Dec 2006

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Bioengineering
  • Biochemistry
  • Molecular Medicine
  • Drug Discovery


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