Mesenchymal stem cells (MSCs) are being widely investigated for the development of novel therapeutic approaches for different cancers, including breast cancer, the leading form of cancer in women. Our previous study showed that the factors secreted by human umbilical cord MSCs (hUCMSCs) induced pyroptosis in the breast cancer cell line MCF7 and our RNA sequencing studies revealed an increase in the expression of the pyroptosis-related gene caspase-4 (CASP4) and nucleotide-binding, leucine-rich repeat pyrin domain-containing protein 1 (NLRP1) in pyroptotic MCF7 cells. Cellular pyroptosis can occur via the canonical pathway (involving caspase-1 and NLRP1) or the noncanonical pathway (involving caspase-4). In this study, we first confirmed that the inflammasome complex formed by NLRP1 and ASC is involved in MCF7 cell pyroptosis induced by hUCMSC-CM. Further, we investigated the role of CASP4 and NLRP1 in MCF7 cell pyroptosis induced by hUCMSC-secreted factors using shRNA-mediated transfection of CASP4 or NLRP1 in MCF7 cells. Cytotoxicity analyses revealed that neither CASP4 knockdown nor NLRP1 knockdown could inhibit the hUCMSC-CM-induced pyroptosis in MCF7 cells. Gene and protein expression analysis showed that hUCMSC-CM induced pyroptosis mainly via the canonical pathway in CASP4 knockdown MCF7 cells but mainly via the noncanonical pathway in NLRP1 knockdown MCF7 cells. Our study provides a foundation for further studies aimed at elucidating the precise mechanism underlying hUCMSC-induced pyroptosis in breast cancer cells and aid the identification of potential therapeutic targets for breast cancer.

中文翻译：

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Caspase-4和NLRP1在hUCMSC分泌因子诱导的MCF7细胞凋亡中的作用。

间充质干细胞（MSCs）被广泛研究以开发针对不同癌症的新型治疗方法，包括乳腺癌，乳腺癌是女性癌症的主要形式。我们以前的研究表明，人脐带间充质干细胞（hUCMSCs）分泌的因子在乳腺癌细胞MCF7中诱导了凋亡，而我们的RNA测序研究显示，与凋亡相关的基因caspase-4（CASP4）和核苷酸的表达增加结合，富含亮氨酸的重复含重复结构域蛋白1（NLRP1）在焦细胞MCF7细胞中。细胞凋亡可以通过经典途径（涉及caspase-1和NLRP1）或非经典途径（涉及caspase-4）发生。在这项研究中，我们首先证实了NLRP1和ASC形成的炎症小体复合物与hUCMSC-CM诱导的MCF7细胞凋亡有关。此外，我们研究的作用CASP4和NLRP1中通过使用的shRNA介导的转hUCMSC分泌因子诱导的MCF7细胞pyroptosis CASP4或NLRP1在MCF7细胞中。细胞毒性分析表明，CASP4均未基因敲低或NLRP1基因敲低均可以抑制hUCMSC-CM诱导的MCF7细胞凋亡。基因和蛋白质表达分析表明，hUCMSC-CM主要通过CASP4敲低的MCF7细胞中的经典途径诱导焦磷酸化，但主要通过NLRP1敲低的MCF7细胞中的非经典途径诱导。我们的研究为进一步研究奠定了基础，这些研究旨在阐明hUCMSC诱导的乳腺癌细胞凋亡的确切机制，并有助于确定潜在的乳腺癌治疗靶点。