Department of Internal Medicine (463), Division of Endocrinology, Radboud University Medical Center, Geert Grooteplein Zuid 8, 6525, GA, Nijmegen, The Netherlands.
Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Geert Grooteplein 32, 6525, GA, Nijmegen, The Netherlands.
Cell Oncol (Dordr). 2019 Oct;42(5):691-703. doi: 10.1007/s13402-019-00457-9. Epub 2019 Jun 14.
Interleukin 32 (IL-32) is a pro-inflammatory cytokine of which different isoforms have been identified. Recently, IL-32 has been shown to act as a potent inducer of cell migration in several types of cancer. Although previous research showed that IL-32 is expressed in differentiated thyroid cancer (TC) cells, the role of IL-32 in TC cell migration has not been investigated. Furthermore, tumour-associated macrophages (TAMs) may play a facilitating role in cancer cell migration. The aim of this study was to explore whether the interaction between TC cells and TAMs results in increased expression of IL-32 in TC cells and to investigate whether this affects TC cell migration.
TPC-1 cells were co-culture with TC-induced or naive macrophages. Next, transcriptome analysis on TPC-1 cells was performed and supernatants were used for stimulation of TPC-1 cells. IL-32β and IL-32γ were exogenously overexpressed in TPC-1 cells using transient transfection, after which an in vitro gap closure assay was performed to assess cell migration, and the expression of migratory factors was assessed using RT-qPCR.
We found that TC-induced macrophages induced IL-32 expression in TC cells and that TAM-derived TNFα was the main inducer of IL-32β expression in TC cells. Overexpression of IL-32β and IL-32γ did not affect TC cell migration, but increased cell death. Finally, we found that IL-32β overexpression led to increased mRNA expression of the pro-survival cytokine IL-8, while the expression of other migratory factors was not affected.
From our data, we conclude that TAM-derived TNFα induces IL-32β in TC cells. Although IL-32β does not affect TC cell migration, alternative splicing of IL-32 towards the IL-32β isoform may be beneficial for TC cell survival through induction of the pro-survival cytokine IL-8.
白细胞介素 32（IL-32）是一种促炎细胞因子，已鉴定出不同的同工型。最近，IL-32 已被证明是几种类型癌症中细胞迁移的有效诱导剂。尽管先前的研究表明 IL-32 在分化型甲状腺癌（TC）细胞中表达，但 IL-32 在 TC 细胞迁移中的作用尚未得到研究。此外，肿瘤相关巨噬细胞（TAMs）可能在癌细胞迁移中发挥促进作用。本研究旨在探讨 TC 细胞与 TAMs 之间的相互作用是否导致 TC 细胞中 IL-32 的表达增加，并研究这是否影响 TC 细胞迁移。
将 TPC-1 细胞与 TC 诱导或幼稚巨噬细胞共培养。接下来，对 TPC-1 细胞进行转录组分析，并使用上清液刺激 TPC-1 细胞。使用瞬时转染在 TPC-1 细胞中外源性过表达 IL-32β 和 IL-32γ，然后进行体外缝隙闭合测定以评估细胞迁移，并使用 RT-qPCR 评估迁移因子的表达。
我们发现 TC 诱导的巨噬细胞诱导 TC 细胞中 IL-32 的表达，并且 TAM 衍生的 TNFα 是 TC 细胞中 IL-32β 表达的主要诱导剂。IL-32β 和 IL-32γ 的过表达并不影响 TC 细胞迁移，但增加了细胞死亡。最后，我们发现 IL-32β 过表达导致促生存细胞因子 IL-8 的 mRNA 表达增加，而其他迁移因子的表达不受影响。
根据我们的数据，我们得出结论，TAM 衍生的 TNFα 诱导 TC 细胞中的 IL-32β。虽然 IL-32β 不影响 TC 细胞迁移，但 IL-32 向 IL-32β 同工型的选择性剪接可能通过诱导促生存细胞因子 IL-8 有利于 TC 细胞存活。
