Bao Wan-Rong, Li Zhi-Peng, Zhang Quan-Wei, Li Li-Feng, Liu Hong-Bing, Ma Dik-Lung, Leung Chung-Hang, Lu Ai-Ping, Bian Zhao-Xiang, Han Quan-Bin
School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Front Pharmacol. 2019 Feb 11;9:1580. doi: 10.3389/fphar.2018.01580. eCollection 2018.
The purpose of this study was to determine if an polysaccharide (RAP) can protect immune cells from the toxic side effects of paclitaxel (Taxol), a powerful anti-tumor drug whose equally powerful side effects limit its clinical use. We hypothesized that RAP can reduce the toxic effects induced by Taxol. To test this hypothesis, we conducted a series of studies and . First, we confirmed RAP's effects utilizing BALB/c mice inoculated with 4T1 mouse breast cancer cells as the tumor model. Mice were treated with RAP and/or Taxol, and the differences in the life spans were recorded. Second, a co-culture cell model was used to study the protective effect of RAP on cells vis-a-vis Taxol. The cell cycle and apoptosis of RAW 264.7 cells that were treated with RAP with/without Taxol were checked by flow cytometry and Hoechst staining. Proteins involved in the cell cycle and apoptosis were also tested by Western blot to reveal the probable mechanism. RAP prolonged the life span of tumor-bearing mice treated with Taxol. The experiments showed that Taxol suppressed the proliferation of RAW 264.7 cells while RAP protected the RAW 264.7 cells from Taxol-induced suppression. The protection is selective because RAP had no effect on 4T1 cells. Furthermore, Taxol clearly led to cell cycle arrest mainly at the G2/M phase and generated cytotoxicity against RAW 264.7 cells, while RAP blocked cell cycle arrest and protected cells from apoptosis. Taxol up-regulated the protein levels of P-HA, PARP, Chk1, p53, and p21 and down-regulated Bcl-Xl and Mcl-1, and RAP reversed the expression of all these proteins. These results suggested that RAP can protect immune cells from Taxol-induced toxicity, by changing the cell cycle and apoptosis.
本研究的目的是确定一种多糖（RAP）是否能够保护免疫细胞免受紫杉醇（泰素）的毒性副作用影响。紫杉醇是一种强效抗肿瘤药物，但其同样强大的副作用限制了其临床应用。我们假设RAP可以降低紫杉醇诱导的毒性作用。为了验证这一假设，我们进行了一系列研究。首先，我们以接种4T1小鼠乳腺癌细胞的BALB/c小鼠作为肿瘤模型，确认了RAP的作用。小鼠接受RAP和/或紫杉醇治疗，并记录寿命差异。其次，使用共培养细胞模型研究RAP对细胞相对于紫杉醇的保护作用。通过流式细胞术和Hoechst染色检查用RAP加/不加紫杉醇处理的RAW 264.7细胞的细胞周期和凋亡情况。还通过蛋白质印迹法检测参与细胞周期和凋亡的蛋白质，以揭示可能的机制。RAP延长了接受紫杉醇治疗的荷瘤小鼠的寿命。实验表明，紫杉醇抑制RAW 264.7细胞的增殖，而RAP保护RAW 264.7细胞免受紫杉醇诱导的抑制。这种保护具有选择性，因为RAP对4T1细胞没有影响。此外，紫杉醇明显导致细胞周期主要停滞在G2/M期，并对RAW 264.7细胞产生细胞毒性，而RAP阻止细胞周期停滞并保护细胞免于凋亡。紫杉醇上调了P-HA、PARP、Chk1、p53和p21的蛋白质水平，下调了Bcl-Xl和Mcl-1，而RAP逆转了所有这些蛋白质的表达。这些结果表明，RAP可以通过改变细胞周期和凋亡来保护免疫细胞免受紫杉醇诱导的毒性。
