Draper James, Alexander Jodi, Nair Rohini M, Scullion Nicole, Narayana Revu V L, Aughton Karen, Herrmann Anne, Vemuganti Geeta K, Kalirai Helen, Coupland Sarah E
Department of Molecular and Clinical Cancer Medicine, ISMIB, University of Liverpool, Liverpool, UK.
School of Medical Sciences, University of Hyderabad, Hyderabad, India.
Curr Eye Res. 2023 Apr;48(4):408-415. doi: 10.1080/02713683.2022.2152055. Epub 2022 Dec 9.
Highly dynamic oxygen gradients occur within tumors that can result in a hypoxic response, contributing to tumor progression and metastasis. Evidence in uveal melanoma (UM) suggests an upregulated hypoxia response in some poor prognosis UM characterized by HIF1α signaling. We aimed to investigate the effects of exposure to hypoxia on tumor growth and dissemination in the chick embryo chorioallantoic membrane (CAM) model.
UM cell lines (MP41, 92.1, MP46, and OMM1) were grown in two-dimensional culture and pre-exposed to hypoxic (1% O) conditions for 72 h. The effects of this hypoxia pre-conditioning on cell number and clonogenicity as compared with 21% O ("normoxia") were investigated prior to transplantation of the cells onto the CAM. Nodule-forming efficiency (NFE), nodule size, and the presence/absence of tumor cell dissemination were determined macroscopically and histologically.
Exposure of UM cell lines to hypoxia upregulated HIF1α expression compared to cells cultured in normoxia. A 72-h pre-exposure to hypoxia significantly reduced cell number and clonogenicity in the MP41 and OMM1 cell lines while it had little effect in 92.1 and MP46 cells. When 72-h hypoxia pre-conditioned cells were grown in three-dimensions on the CAM, a reduction in NFE and nodule size was observed when compared with normoxic UM cells. All nodules were composed of proliferating (Ki-67+) Melan-A + cells and displayed chick blood vessel recruitment. Spread of UM cells into the adjacent CAM was observed; however, dissemination to the chick liver was only seen with 92.1 cells grown under normoxia.
Hypoxia pre-conditioning does not appear to drive a metastatic phenotype in UM; however, further understanding of how oxygen dynamics within the tumor microenvironment regulates HIF1 signaling is needed to determine whether inhibitors of HIF signaling represent a therapeutic option in metastatic UM.
肿瘤内会出现高度动态的氧梯度，这可能导致缺氧反应，促进肿瘤进展和转移。葡萄膜黑色素瘤（UM）的相关证据表明，一些以HIF1α信号传导为特征的预后不良的UM中，缺氧反应上调。我们旨在研究在鸡胚绒毛尿囊膜（CAM）模型中，暴露于缺氧环境对肿瘤生长和扩散的影响。
UM细胞系（MP41、92.1、MP46和OMM1）在二维培养中生长，并预先暴露于缺氧（1% O₂）条件下72小时。在将细胞移植到CAM上之前，研究这种缺氧预处理与21% O₂（“常氧”）相比对细胞数量和克隆形成能力的影响。通过宏观和组织学方法确定结节形成效率（NFE）、结节大小以及肿瘤细胞是否扩散。
与在常氧条件下培养的细胞相比，UM细胞系暴露于缺氧环境会使HIF1α表达上调。预先暴露于缺氧环境72小时显著减少了MP41和OMM1细胞系中的细胞数量和克隆形成能力，而对92.1和MP46细胞影响不大。当将经过72小时缺氧预处理的细胞在CAM上进行三维培养时，与常氧UM细胞相比，观察到NFE和结节大小有所降低。所有结节均由增殖的（Ki-67+）Melan-A+细胞组成，并显示出鸡血管募集现象。观察到UM细胞扩散到相邻的CAM中；然而，仅在常氧条件下生长的92.1细胞中观察到扩散至鸡肝脏。
缺氧预处理似乎不会在UM中驱动转移表型；然而，需要进一步了解肿瘤微环境中的氧动力学如何调节HIF信号传导，以确定HIF信号抑制剂是否代表转移性UM的一种治疗选择。
