Abstract
Endometrial cancer (EC) is the most common gynecologic malignancy in the world and incidence is steadily increasing. The Levonorgestrel Intrauterine System (LNG-IUS) is an alternative conservative treatment for early-stage EC, however, Levonorgestrel (LNG) resistance occurs for 1 in 3 people. This study aimed to present potential LNG resistance mechanisms and identify differentially expressed genes (DEGs) in EC cell lines. Two LNG resistant cell lines were developed through long term culture in LNG (MFE296
and MFE319
). Whole transcriptome sequencing was carried out on triplicate RNA samples. EdgeR v3.32.1 was used to identify differentially DEGs. Blast2go V6.0 (BioBam software) was used for functional annotation and analysis of genomic datasets. Protein interactions were investigated using the STRING database, including the identification of genes with high levels of interaction (HUB genes). Select DEGs and HUB genes were validated by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Fifteen DEGs were identified according to FDR < 0.05 and logFC < 2. Protein analysis identified six HUB genes with a degree of connectivity > 10. Relative mRNA expression of MAOA, MAOB, THRSP, CD80, NDP, LINC01474, DUSP2 and CXCL8 was significantly upregulated in both LNG
cell lines. Relative protein expression of GNAO1 and MAOA were significantly upregulated in both LNG
cell lines. This research identified novel markers of resistance in LNG
cell lines. We discussed potential mechanisms of LNG resistance including dedifferentiation and immunostimulation. The next step for this research is to validate these findings further in both translational and clinical settings.