Department of Bachelor's Degree Program for Indigenous Peoples in Senior Health and Care Management, National Taitung University, Taitung, Taiwan.
Master Program in Biomedical Science, National Taitung University, Taitung, Taiwan.
Drug Dev Res. 2023 Jun;84(4):767-776. doi: 10.1002/ddr.22057. Epub 2023 Apr 2.
Our previous studies have shown that the plasminogen activator (PA) and matrix metalloproteinases (MMPs) proteinase systems were highly expressed in highly malignant liver cancer cells and regulated by PKCα. This study investigates whether the PKCα regulation of PA and MMPs systems is conducted through p38 mitogen-activated protein kinase (MAPK) signaling and the pathway is responsible for promoting cell progression. We found that the expressions of p38 MAPK in both highly malignant HA22T/VGH and SK-Hep-1 liver cancer cells were higher than that in other lower malignancy liver cancer cells. Since PKCα activates p38 MAPK in progression of liver cancer, we suspected the PKCα/p38 MAPK signaling pathway to be involved in the regulation of MMPs and PA systems. When SK-Hep-1 cells were treated with SB203580 or DN-p38, only MMP-1 and u-PA mRNA expressions decreased. The p38 MAPK inhibition also decreased the cell migration and invasion. In addition, the mRNA decay assays showed that the higher expressions of MMP-1 and u-PA mRNA in SK-Hep-1 cells were due to the alteration of mRNA stability by p38 MAPK inhibition. Zymography of SK-Hep-1 cells treated with siPKCα vector also showed the decrease of the activity of MMP-1 and u-PA and confirmed changes in mRNA level. Furthermore, only the transfection of MKK6 to the siPKCα-treated SK-Hep-1 stable clone cell restored the attenuation of MMP-1 and u-PA expressions. The treatment of SK-Hep-1 cells with either inhibitor of MMP-1 or u-PA reduced migration, and the reduction was enhanced with both inhibitors. In addition, tumorigenesis was also reduced with both inhibitors. These data suggest a novel finding that MMP-1 and u-PA are critical components in PKCα/MKK6/p38 MAPK signaling pathway which mediates liver cancer cell progression, and that the targeting of both genes may be a viable approach in liver cancer treatment.
我们之前的研究表明，纤溶酶原激活物 (PA) 和基质金属蛋白酶 (MMPs) 蛋白酶系统在高度恶性肝癌细胞中高度表达，并受 PKCα 调节。本研究探讨了 PKCα 是否通过 p38 丝裂原活化蛋白激酶 (MAPK) 信号通路调节 PA 和 MMPs 系统，以及该通路是否负责促进细胞进展。我们发现，高度恶性 HA22T/VGH 和 SK-Hep-1 肝癌细胞中的 p38 MAPK 表达均高于其他低度恶性肝癌细胞。由于 PKCα 在肝癌进展中激活 p38 MAPK，我们怀疑 PKCα/p38 MAPK 信号通路参与了 MMPs 和 PA 系统的调节。当 SK-Hep-1 细胞用 SB203580 或 DN-p38 处理时，只有 MMP-1 和 u-PA 的 mRNA 表达减少。p38 MAPK 抑制也降低了细胞迁移和侵袭。此外，mRNA 衰减实验表明，SK-Hep-1 细胞中 MMP-1 和 u-PA 的高表达是由于 p38 MAPK 抑制改变了 mRNA 稳定性。用 siPKCα 载体处理 SK-Hep-1 细胞的酶谱分析也显示 MMP-1 和 u-PA 的活性降低，并证实了 mRNA 水平的变化。此外，只有将 MKK6 转染到 siPKCα 处理的 SK-Hep-1 稳定克隆细胞中，才能恢复 MMP-1 和 u-PA 表达的减弱。用 MMP-1 或 u-PA 的抑制剂处理 SK-Hep-1 细胞，均能减少细胞迁移，而两者同时使用时，迁移减少更为明显。此外，肿瘤生成也减少了。这些数据表明了一个新的发现，即 MMP-1 和 u-PA 是 PKCα/MKK6/p38 MAPK 信号通路介导肝癌细胞进展的关键组成部分，靶向这两个基因可能是肝癌治疗的一种可行方法。
