Background

Pharbitis nil (L.) Choisy (PN) is used as a traditional herb in East Asia and exhibits anti-parasitic, purgative, diuretic, anti-inflammatory, and anti-cancer activities. However, the molecular mechanisms underlying the anti-cancer activity are not well understood.

Objective

This study aims to elucidate the effects of reactive oxygen species (ROS), generated after treatment with the compound PN, on the induction of apoptosis and autophagy, which are pathways that underly the mechanisms of cell death and cell survival in human prostate cancer cells.

Results

The MTT assay and western blot analysis were used to assess the effects of compound PN on cell viability and the expression of apoptosis- and autophagy-related proteins in prostate cancer PC-3 cells. The effects of PN on apoptosis (via annexin V/propidium iodide staining), autophagy (via acridine orange staining), and ROS (via DCFH-DA staining) were investigated using flow cytometry. Compound PN induced the production of intracellular and mitochondrial ROS leading to increased apoptosis and autophagy in PC-3 cells. Interestingly, pretreatment with N-acetyl-l-cysteine (NAC), an intracellular ROS scavenger, enhanced compound PN-induced apoptosis, but reduced levels of autophagy. In contrast, pretreatment with diphenyleneiodonium (DPI), an inhibitor of mitochondrial ROS, reduced compound PN-induced apoptosis and enhanced autophagy. Inhibition of autophagy led to acceleration of apoptosis in a PN-induced ROS-dependent manner. Compound PN-induced ROS production from two different sources, an intracellular source and mitochondrial source. ROS production in these differing locations had different effects on apoptosis and autophagy. They acted either by promoting cell death or cell survival through regulating autophagy to either escape or enhance apoptotic cell death.

Conclusion

This crosstalk between ROS-activated signals in apoptosis and autophagy induction by PN provides new insights into the molecular mechanisms of this compound and suggests that PN may be a potential therapy for prostate cancer treatment.

中文翻译：

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活性氧在化合物PN诱导的前列腺癌细胞自噬和凋亡中的双重作用

背景

零陵兰（L.）Choisy（PN）在东亚用作传统草药，具有抗寄生虫，泻药，利尿，抗炎和抗癌的作用。但是，抗癌活性的分子机制尚不清楚。

目的

这项研究旨在阐明用化合物PN处理后产生的活性氧（ROS）对细胞凋亡和自噬的诱导作用，这是人类前列腺癌细胞中细胞死亡和细胞存活机制的基础。

结果

使用MTT分析和western印迹分析来评估化合物PN对前列腺癌PC-3细胞的细胞活力以及凋亡和自噬相关蛋白表达的影响。使用流式细胞仪研究了PN对凋亡（通过膜联蛋白V /碘化丙啶染色），自噬（通过a啶橙染色）和ROS（通过DCFH-DA染色）的影响。化合物PN诱导了细胞内和线粒体ROS的产生，从而导致PC-3细胞凋亡和自噬增加。有趣的是，用N-乙酰基-l预处理-半胱氨酸（NAC），一种细胞内ROS清除剂，增强了化合物PN诱导的细胞凋亡，但降低了自噬水平。相比之下，用线粒体ROS抑制剂联苯二碘铵（DPI）进行预处理，可减少化合物PN诱导的细胞凋亡并增强自噬。自噬的抑制导致以PN诱导的ROS依赖性方式加速凋亡。化合物PN诱导的ROS产生来自两种不同的来源，细胞内来源和线粒体来源。在这些不同位置的ROS产生对细胞凋亡和自噬具有不同的影响。它们通过调节自噬逃逸或增强凋亡性细胞死亡来促进细胞死亡或细胞存活。

结论

凋亡中的ROS激活信号与PN自噬诱导之间的这种串扰为该化合物的分子机制提供了新见识，并表明PN可能是前列腺癌治疗的潜在疗法。