Estrogen receptor2 regulates interlukin-12 receptor2 expression via p38 mitogen-activated protein kinase signaling and inhibits non-small-cell lung cancer proliferation and invasion

Lung cancer is one of the most common types of cancer and is the leading cause of cancer-related mortality worldwide. Estrogens are known to be involved in the development and progression of non-small-cell lung cancer (NSCLC). These effects are initially mediated through binding of estrogen to estrogen receptors (ERs), in particular ER2. Our preliminary studies demonstrated that ER2 and interleukin-12 receptor2 (IL-12R2) expression are correlated in NSCLC. The present study investigated the expression of these proteins in NSCLC cells and how changes in their expression affected cell proliferation and invasion. In addition, it aimed to explore whether p38 mitogen-activated protein kinase (p38MAPK) is involved in the regulation of IL-12R2 expression by ER2. An immunocytochemical array was used to observe the distribution of ER2 and IL-12R2. Co-immuoprecipitation was employed to observe the interaction between p38MAPK and IL-12R2, by varying the expression of ER2 and p38MAPK. Western-blot analysis and reverse transcription-polymerase chain reaction assays were used to investigate the mechanism underlying ER2 regulation of IL-12R2 expression. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, scratch wound healing and Transwell assays were used to investigate the impact of ER2 on proliferative, invasive and migratory abilities of NSCLC cells. ER2 was predominantly found in the cytoplasm and nucleus, whilst IL-12R2 was largely confined to the cytoplasm, although a degree of expression was observed in the nucleus. Compared with normal bronchial epithelial cells, IL-12R2 and ER2 were overexpressed in the NSCLC cell groups. Coimmuoprecipitation demonstrated an interaction between p38MAPK and IL-12R2. ER2 appeared to upregulate IL-12R2 expression and inhibition of p38MAPK attenuated this effect. ER2 and IL-12R2 expression inhibited the proliferation, metastasis and invasion of NSCLC cell lines, but knockout of IL-12R2, even in the presence of ER2, led to an increase in NSCLC cell proliferation and invasiveness. In conclusion, to the best of our knowledge this study is the first to demonstrate that IL-12R2 may be important in the mechanisms underlying ER2 inhibition of NSCLC development, and that this interaction may be mediated via p38MAPK.