Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
Acta Biochim Biophys Sin (Shanghai). 2021 Oct 12;53(10):1387-1397. doi: 10.1093/abbs/gmab115.
Photodynamic therapy (PDT), which is a new method for treating tumors, has been used in the treatment of cancer. In-depth research has shown that PDT cannot completely kill tumor cells, indicating that tumor cells are resistant to PDT. Glucose regulatory protein 78 (GRP78), which is a key regulator of endoplasmic reticulum stress, has been confirmed to be related to tumor resistance and recurrence, but there are relatively few studies on the further mechanism of GRP78 in PDT. Our experiment aimed to observe the role of GRP78 in HOS human osteosarcoma cells treated with pyropheophorbide-α methyl ester-mediated photodynamic therapy (MPPα-PDT) and to explore the possible mechanism by which the silencing of GRP78 expression enhances the sensitivity of HOS osteosarcoma cells to MPPα-PDT. HOS osteosarcoma cells were transfected with siRNA-GRP78. Apoptosis and reactive oxygen species (ROS) levels were detected by Hoechst staining and flow cytometry, cell viability was detected by Cell Counting Kit-8 assay, GRP78 protein fluorescence intensity was detected by immunofluorescence, and apoptosis-related proteins, cell proliferation-related proteins, and Wnt pathway-related proteins were detected by western blot. The results showed that MPPα-PDT can induce HOS cell apoptosis and increase GRP78 expression. After successful siRNA-GRP78 transfection, HOS cell proliferation was decreased, and apoptosis-related proteins expressions was increased, Wnt/β-catenin-related proteins expressions was decreased, and ROS levels was increased. In summary, siRNA-GRP78 enhances the sensitivity of HOS cells to MPPα-PDT, the mechanism may be related to inhibiting Wnt pathway activation and increasing ROS levels.
光动力疗法（PDT）是一种治疗肿瘤的新方法，已用于癌症的治疗。深入的研究表明，PDT 并不能完全杀死肿瘤细胞，这表明肿瘤细胞对 PDT 有抗性。葡萄糖调节蛋白 78（GRP78）是内质网应激的关键调节剂，已被证实与肿瘤耐药和复发有关，但关于 GRP78 在 PDT 中进一步机制的研究相对较少。我们的实验旨在观察 GRP78 在 Pyropheophorbide-α 甲酯介导的光动力疗法（MPPα-PDT）治疗 HOS 人骨肉瘤细胞中的作用，并探讨沉默 GRP78 表达增强 HOS 骨肉瘤细胞对 MPPα-PDT 敏感性的可能机制。用 siRNA-GRP78 转染 HOS 骨肉瘤细胞。通过 Hoechst 染色和流式细胞术检测细胞凋亡和活性氧（ROS）水平，通过细胞计数试剂盒-8 检测细胞活力，通过免疫荧光检测 GRP78 蛋白荧光强度，通过 Western blot 检测凋亡相关蛋白、细胞增殖相关蛋白和 Wnt 通路相关蛋白。结果表明，MPPα-PDT 可诱导 HOS 细胞凋亡并增加 GRP78 表达。成功转染 siRNA-GRP78 后，HOS 细胞增殖减少，凋亡相关蛋白表达增加，Wnt/β-catenin 相关蛋白表达减少，ROS 水平增加。综上所述，siRNA-GRP78 增强了 HOS 细胞对 MPPα-PDT 的敏感性，其机制可能与抑制 Wnt 通路激活和增加 ROS 水平有关。
