The Effects of GnRH-(1-5) on Tumor-Derived Endometrial Cancer Cell Lines
Presentation Number: SUN 496
Date of Presentation: April 2nd, 2017
Madelaine J Cho-Clark*, T John Wu and Darwin Omar Larco
Uniformed Services University, Bethesda, MD
Gonadotropin-Releasing Hormone (GnRH) is a central regulator of the reproduction. In addition, GnRH and GnRHR also regulate processes that are independent of reproductive function. Recent studies have suggested that GnRH can exert local effects in an autocrine manner. GnRH is processed by endopeptidase EP24.15 in the extracellular space to generate the bioactive metabolite, GnRH-(1-5). We have previously demonstrated in the Ishikawa and ECC-1 endometrial cancer cell lines that GnRH-(1-5) elicits transactivation of the epidermal growth factor receptor (EGFR) pathway by stimulating the release of EGF (epidermal growth factor) to promote cell migration through a GnRH-(1-5) receptor, the orphan G-protein coupled receptor, GPR101. In the current study, we determined whether the effects of GnRH-(1-5) on endometrial cancer were stage-dependent utilizing tumor-derived cell lines ACI-181, ACI-52, and ACI-80 representing Stage 1, 2, and 3 respectively. Prior to the study, the expression of GPR101 in the ACI cell lines were confirmed by Western blot analysis. In all ACI cell lines, treatment with 100nM GnRH-(1-5) did not change the phosphorylation of EGFR at Tyr1068. However in the ACI-181 cell line, significant (p < 0.05) increases in phosphorylation of downstream transducer ERK was limited to the pERK2 subunit, paralleling our previous findings in the Ishikawa cell line. The effect of GnRH-(1-5) on cell migration was studied using the wound closure assay. Treatment with GnRH-(1-5) significantly increased (p < 0.05) migration in the ACI-181 and ACI-52 cells line. ACI-80 remained unaffected. Interestingly, GnRH-(1-5) increased (p<0.05) transforming growth factor β (TGFβ) activity in ACI-52 and ACI-181 cells. Furthermore, the mechanism for increased (p<0.05) TGFβ-1, TGFβ-2, TGFβ-3 release was determined to be regulated by MMP-9 by utilizing MMP-9 Inhibitor I and TGFβ Bioplex Assay in the Ishikawa cell line. This study suggests that GnRH-(1-5) and MMP-9 may have an important role in regulating autocrine-dependent cell growth and migration of endometrial cancer cells. These new findings suggest early stages of endometrial cancer may be more sensitive and dependent on TGF-β and other growth factors to stimulate migratory cascades.
Nothing to Disclose: MJC, TJW, DOL