The estrogen/miR‐338‐3p/ADAM17 axis enhances the viability of breast cancer cells via suppressing NK cell's function

Abstract

AbstractNatural killer (NK) cells are the critical elements of the innate immune response and implicated in rapidly recognizing and eliminating cancer cells. However, the tumor‐suppressive ability of NK cells is often impaired in several cancer types. The critical roles of microRNAs have been elucidated by increasing evidences, while the regulation of miR‐338‐3p in anti‐tumor activation of NK cells and its relationship with estrogen in breast cancer (BC) are still confusing. Here, miR‐338‐3p level was found to be significantly downregulated in BC tissues and estrogen receptor positive (ER+) cells, this difference was more obvious in ER+ patients or BC patients at advanced stage (TNM III and IV). MiR‐338‐3p level was shown to be downregulated by 17β‐estradiol in BC cells (MDA‐MB‐231 cells and MCF‐7) in vitro. MiR‐338‐3p overexpression decreased disintegrin and metalloprotease‐17 (ADAM17) secretion in MDA‐MB‐231 (ER−) and MCF‐7 (ER+) cells. In addition, miR‐338‐3p overexpression or treatment with anti‐ADAM17 antibody could down‐regulate granzyme B, CD16, and NKG2D in NK cells, which was reversed by human recombinant ADAM17. Furthermore, these educated NK cells could promote the viability of MDA‐MB‐231 or MCF‐7 cells. Taken together, our results demonstrate that miR‐338‐3p was negatively regulated by estrogen in BC cells, impairing NK cell's activity by the up‐regulation of ADAM17, and conversely promoted the viability of BC cells. Therefore, the estrogen/miR‐338‐3p/ADAM17 axis is critically implicated in BC pathogenesis and may provide potential targets for BC diagnosis and treatment.