Bian Zhongbo, Sun Xiaodie, Liu Lulin, Qin Yong, Zhang Qiuyu, Liu Huahuan, Mao Lianzhi, Sun Suxia
Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China.
Cancers (Basel). 2023 Jan 9;15(2):423. doi: 10.3390/cancers15020423.
Colorectal cancer (CRC) is one of the most common malignancies, and effective treatment and prevention methods are lacking. Sodium butyrate (NaB) is a short-chain fatty acid produced by intestinal microbial fermentation of dietary fiber. It has been shown to be effective in inhibiting CRC, but the mechanism is not known.
Human normal intestinal epithelial cell line FHT and colorectal tumor cell line HCT-116 were treated with NaB alone or in combination with different programmed cell death inhibitors. Cell activity was then assessed with MTT assays and PI staining; ferroptosis with Fe, glutathione (GSH), and lipid peroxidation assays; signaling pathway screening with PCR arrays; and CD44, SCL7A11, and GPX4 expression with Western blotting. A CD44-overexpressing HCT-116 cell line was constructed to determine the effect of the overexpression of CD44 on NaB-induced ferroptosis. The synergistic effect of co-treatment with NaB and Erastin was assessed by isobolographic analysis.
NaB induced apoptosis and ferroptosis in HCT-116 cells but only induced low-level apoptosis in FHC cells. Moreover, NaB significantly increased intracellular Fe and promoted GSH depletion and lipid peroxidation in HCT-116 cells. Ferroptosis-related qPCR array analysis identified CD44/SLC7A11 as a potential effector molecular of NaB-induced ferroptosis. NaB significantly inhibited the expression of CD44 and SLC7A11 in mouse CRC tissues. A CD44 overexpressed HCT-116 cell line was used to verify that CD44/SLC7A11 was a key signaling pathway that NaB-induced GSH depletion, lipid peroxidation accumulation, and ferroptosis in HCT-116 cells. Examination of whether NaB can increase the effect of ferroptosis agents showed that NaB, in combination with Erastin, a ferroptosis inducer, further promoted HCT-116 cell death and increased changes of ferroptosis markers.
Our results suggest that NaB induces ferroptosis in CRC cells through the CD44/SLC7A11 signaling pathway and has synergistic effects with Erastin. These results may provide new insights into CRC prevention and the combined use of NaB and ferroptosis-inducing agents.
结直肠癌（CRC）是最常见的恶性肿瘤之一，且缺乏有效的治疗和预防方法。丁酸钠（NaB）是膳食纤维经肠道微生物发酵产生的一种短链脂肪酸。已证明其在抑制结直肠癌方面有效，但其机制尚不清楚。
将人正常肠上皮细胞系FHT和结直肠肿瘤细胞系HCT-116单独用NaB处理或与不同的程序性细胞死亡抑制剂联合处理。然后用MTT法和PI染色评估细胞活性；用铁、谷胱甘肽（GSH）和脂质过氧化测定法评估铁死亡；用PCR阵列进行信号通路筛选；用蛋白质印迹法检测CD44、SCL7A11和GPX4的表达。构建CD44过表达的HCT-116细胞系以确定CD44过表达对NaB诱导的铁死亡的影响。通过等效线图分析评估NaB与艾拉司丁联合治疗的协同作用。
NaB诱导HCT-116细胞凋亡和铁死亡，但仅诱导FHC细胞低水平凋亡。此外，NaB显著增加HCT-116细胞内铁含量，促进GSH消耗和脂质过氧化。铁死亡相关的qPCR阵列分析确定CD44/SLC7A11是NaB诱导铁死亡的潜在效应分子。NaB显著抑制小鼠结直肠癌组织中CD44和SLC7A11的表达。用CD44过表达的HCT-116细胞系验证CD44/SLC7A11是NaB诱导HCT-116细胞GSH消耗、脂质过氧化积累和铁死亡的关键信号通路。检测NaB是否能增强铁死亡诱导剂的作用，结果显示NaB与铁死亡诱导剂艾拉司丁联合使用可进一步促进HCT-116细胞死亡，并增加铁死亡标志物的变化。
我们的结果表明，NaB通过CD44/SLC7A11信号通路诱导结直肠癌细胞铁死亡，并与艾拉司丁具有协同作用。这些结果可能为结直肠癌的预防以及NaB与铁死亡诱导剂的联合使用提供新的见解。
