Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA.
Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.
Neoplasia. 2023 Feb;36:100866. doi: 10.1016/j.neo.2022.100866. Epub 2022 Dec 29.
High grade serous ovarian cancer (HGSC) arises from the fimbriated end of the fallopian tube epithelium (FTE), and in some cases, the ovarian surface epithelium (OSE). PAX8 is a commonly used biomarker for HGSC and is expressed in ∼90% of HGSC. Although the OSE does not express PAX8, murine models of HGSC derived from the OSE acquire PAX8, suggesting that it is not only a marker of Müllerian origin, but also an essential part of cancer progression, potentially from both the OSE and FTE. Previously, we have shown that PAX8 loss in HGSC cells causes tumor cell death and reduces cell migration and invasion. Herein, secretome analysis was performed in PAX8 deleted cells and we identified a reduction of the extracellular matrix (ECM) components, collagen and fibronectin. Immunoblotting and immunofluorescence in PAX8 deleted HGSC cells further validated the results from the secretome analysis. PAX8 loss reduced the amount of secreted TGFbeta, a cytokine that plays a crucial role in remodelling the tumor microenvironment. Furthermore, PAX8 loss reduced the integrity of 3D spheroids and caused a reduction of ECM proteins fibronectin and collagen in 3D cultures. Due to the ubiquitous nature of PAX8 in HGSC, regardless of cell origin, and the association of its reduced expression with decreasing tumor burden, a PAX8 inhibitor could be a promising drug target against various types of HGSC. To accomplish this, we generated a murine oviductal epithelial (MOE) cell line stably expressing PAX8 promoter-luciferase. Using this cell line, we performed a screening assay with a library of FDA-approved drugs (Prestwick Library) and quantitatively assessed these compounds for their inhibition of PAX8. We identified two hits: losartan and captropril, both inhibitors of the renin-angiotensin pathway that inhibit PAX8 expression and function. Overall, this study validates PAX8 as a regulator of ECM deposition in the tumor microenvironment.
高级别浆液性卵巢癌（HGSC）起源于输卵管纤毛上皮（FTE）的顶端，在某些情况下，起源于卵巢表面上皮（OSE）。PAX8 是 HGSC 的常用生物标志物，约 90%的 HGSC 中表达。尽管 OSE 不表达 PAX8，但源自 OSE 的 HGSC 小鼠模型获得了 PAX8，表明它不仅是 Müllerian 起源的标志物，而且也是癌症进展的重要组成部分，可能来自 OSE 和 FTE。以前，我们已经表明，HGSC 细胞中 PAX8 的缺失会导致肿瘤细胞死亡，并减少细胞迁移和侵袭。在此，我们对 PAX8 缺失的细胞进行了分泌组分析，发现细胞外基质（ECM）成分胶原蛋白和纤维连接蛋白减少。在 PAX8 缺失的 HGSC 细胞中进行免疫印迹和免疫荧光验证了分泌组分析的结果。PAX8 的缺失减少了转化生长因子β（TGFβ）的分泌量，TGFβ 是一种在重塑肿瘤微环境中起关键作用的细胞因子。此外，PAX8 的缺失降低了 3D 球体的完整性，并导致 3D 培养物中 ECM 蛋白纤维连接蛋白和胶原蛋白减少。由于 PAX8 在 HGSC 中的普遍存在，无论细胞起源如何，以及其表达减少与肿瘤负担降低相关，因此 PAX8 抑制剂可能是针对各种类型 HGSC 的有前途的药物靶点。为了实现这一目标，我们构建了一种稳定表达 PAX8 启动子-荧光素酶的鼠输卵管上皮（MOE）细胞系。使用该细胞系，我们对 FDA 批准药物库（Prestwick 文库）进行了筛选实验，并定量评估了这些化合物对 PAX8 的抑制作用。我们发现了两种有效化合物：氯沙坦和卡托普利，它们都是肾素-血管紧张素途径的抑制剂，可抑制 PAX8 的表达和功能。总体而言，这项研究验证了 PAX8 作为肿瘤微环境中 ECM 沉积的调节剂。
