P2.01-059 Regulation of Glycodelin Expression - An Immunomodulatory and Pregnancy Associated Protein in NSCLC

Abstract

Glycodelin (gene name: progesterone-associated endometrial protein, PAEP) is a protein initially described as an immune system modulator during the establishment of pregnancy. Former studies determined an atypical expression and secretion of glycodelin in non-small cell lung cancer (NSCLC), the most common type of lung cancer. To date, there is not much known about the signaling pathway which regulates PAEP/glycodelin expression in cancer. However, initial experiments already revealed an inducing effect of epidermal growth factor (EGF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), lysophosphatidic acid (LPA) and Phorbol 12-myristate 13 acetate (PMA) on PAEP/glycodelin expression in two NSCLC cell lines (H1975 and 2106T). In this study, we analyzed an extended number of possible regulatory candidates to acquire a more detailed view on the regulatory pathway of PAEP/glycodelin in NSCLC. A lung adenocarcinoma (H1975) and a lung squamous cell carcinoma cell line (2106T) were transfected with siRNA targeting nuclear factor κB1 (NFκB1) or treated with human chorionic gonadotropin (hCG), transforming growth factor-β (TGF-β) 1, -2, -3, protein kinase C (PKC) activator bryostatin 1 and PKC inhibitor GF109203x, respectively. Additionally, combined treatments with GF109203x and TGF-β 1,-2, EGF or HB-EGF were performed. PAEP expression in the manipulated cells was determined by quantitative polymerase chain reaction (qPCR), while glycodelin expression or secretion was detected by western blot analysis. NFκB1 siRNA transfection resulted in decreased PAEP and glycodelin amounts (H1975 and 2106T), whereas hCG (H1975 and 2106T) and TGF-β 1, -2, -3 (2106T) treatment led to higher levels. In bryostatin treated cells (H1975 and 2106T), PAEP/glycodelin expression was upregulated. The contradictory effect could be demonstrated for cells treated with the PKC inhibitor GF109203x alone and in combination with TGF-β 1,-2, EGF or HB-EGF (H1975 and 2106T). This study revealed that there are different regulation mechanisms of PAEP/glycodelin induction in NSCLC. Especially, PKC seems to be involved as a key molecule. The investigated candidates which play a crucial role in driving this signaling pathway are all known to promote the development of cancer. Elucidating the regulatory pathway of the immune system modulating protein glycodelin might reveal a potential strategy to weaken the immune system defense of lung tumors.