miR-4299 inhibits tumor progression in pancreatic cancer through targeting ADAM17

Pancreatic cancer (PC) is one of the most aggressive malignant tumors in human beings. Tumor capacity of evading immune-mediated lysis is a critical step in PC malignant progression. We aimed to evaluate the underlying regulatory mechanism of miR-4299 in the proliferation, metastasis, apoptosis, and immune escape in PC. miR-4299 and ADAM17 expressions in PC tissues and cell lines were detected using qRT-PCR. MTT assay and flow cytometry were used to detect cell viability and apoptosis, respectively. A luciferase reporter gene assay was conducted to confirm the targeted relationship between miR-4299 and ADAM17. Xenograft tumors in nude mice were used to detect tumorigenesis in vivo. PC cells were co-cultured with NK cells for determining the immune escape ability. NKG2D-positive rate of NK cells was detected using flow cytometry; NK cell-killing ability was detected using MTT assay. miR-4299 was downregulated in PC tissues and cell lines. miR-4299 inhibited PC cell proliferation and invasion, promoted cell apoptosis, and reduced PC tumor growth in vivo. ADAM17 3'UTR directly bound to miR-4299. ADAM17 overexpression could reverse miR-4299 effects on PC cell viability, invasion, apoptosis, and immune escape. miR-4299 exerted suppressive effects on PC cell proliferation, invasion, and immune escape via targeting ADAM17 expression. This study revealed a novel miR-4299/ADAM17 axis-modulating PC progression and proposed to concern the immune regulatory mechanism of miRNAs in PC development.