Some lichens provide the resources of common traditional medicines and show anticancer effects. However, the anticancer effect of Usnproliea barbata (U. barbata) is rarely investigated, especially for oral cancer cells. The aim of this study was to investigate the cell killing function of methanol extracts of U. barbata (MEUB) against oral cancer cells. MEUB shows preferential killing against a number of oral cancer cell lines (Ca9-22, OECM-1, CAL 27, HSC3, and SCC9) but rarely affects normal oral cell lines (HGF-1). Ca9-22 and OECM-1 cells display the highest sensitivity to MEUB and were chosen for concentration effect and time course experiments to address its cytotoxic mechanisms. MEUB induces apoptosis of oral cancer cells in terms of the findings from flow cytometric assays and Western blotting, such as subG1 accumulation, annexin V detection, and pancaspase activation as well as poly (ADP-ribose) polymerase (PARP) cleavage. MEUB induces oxidative stress and DNA damage of oral cancer cells following flow cytometric assays, such as reactive oxygen species (ROS)/mitochondrial superoxide (MitoSOX) production, mitochondrial membrane potential (MMP) depletion as well as overexpression of γH2AX and 8-oxo-2′deoxyguanosine (8-oxodG). All MEUB-induced changes in oral cancer cells were triggered by oxidative stress which was validated by pretreatment with antioxidant N-acetylcysteine (NAC). In conclusion, MEUB causes preferential killing of oral cancer cells and is associated with oxidative stress, apoptosis, and DNA damage.

中文翻译：

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半夏松萝的甲醇提取物通过氧化应激诱导细胞杀伤，凋亡和对口腔癌细胞的DNA损伤。

一些地衣提供了传统传统药物的资源并显示出抗癌作用。然而，很少研究Usproproliea barbata（U. barbata）的抗癌作用，特别是对于口腔癌细胞。这项研究的目的是调查半枝莲甲醇提取物的细胞杀伤功能。（MEUB）对抗口腔癌细胞。MEUB对多种口腔癌细胞系（Ca9-22，OECM-1，CAL 27，HSC3和SCC9）表现出优先杀伤作用，但很少影响正常的口腔癌细胞系（HGF-1）。Ca9-22和OECM-1细胞显示出对MEUB的最高敏感性，并被选择用于浓度效应和时程实验以解决其细胞毒性机制。根据流式细胞仪检测和Western印迹的发现，例如subG1积累，膜联蛋白V检测和pancaspase活化以及聚（ADP-核糖）聚合酶（PARP）裂解，MEUB诱导口腔癌细胞凋亡。在流式细胞仪检测后，MEUB会诱导口腔癌细胞的氧化应激和DNA损伤，例如活性氧（ROS）/线粒体超氧化物（MitoSOX）的产生，线粒体膜电位（MMP）耗竭以及γH2AX和8-oxo-2'脱氧鸟苷（8-oxodG）的过表达。MEUB诱导的所有口腔癌细胞变化均由氧化应激触发，氧化应激已通过抗氧化剂预处理得到验证N-乙酰半胱氨酸（NAC）。总之，MEUB导致口腔癌细胞的优先杀伤，并与氧化应激，细胞凋亡和DNA损伤有关。