Jin Xuefang, Wu Nana, Dai Juji, Li Qiuxia, Xiao XiaoQiang
School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.
The Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, China.
Cancer Med. 2017 Feb;6(2):424-438. doi: 10.1002/cam4.977. Epub 2016 Dec 29.
Sodium butyrate (NaBu) and sodium 4-phenylbutyrate (4PBA) have promising futures in cancer treatment; however, their underlying molecular mechanisms are not clearly understood. Here, we show A549 cell death induced by NaBu and 4PBA are not the same. NaBu treatment induces a significantly higher level of A549 cell death than 4PBA. A gene expression microarray identified more than 5000 transcripts that were altered (>1.5-fold) in NaBu-treated A549 cells, but fewer than 2000 transcripts that were altered in 4PBA. Moreover, more than 100 cell cycle-associated genes were greatly repressed by NaBu, but slightly repressed by 4PBA; few genes were significantly upregulated only in 4PBA-treated cells. Gene expression was further validated by other experiments. Additionally, A549 cells that were treated with these showed changes in glucose consumption, caspase 3/7 activation and histone modifications, as well as enhanced mitochondrial superoxide production. TXNIP was strongly induced by NaBu (30- to 40-fold mRNA) but was only slightly induced by 4PBA (two to fivefold) in A549 cells. TXNIP knockdown by shRNA in A549 cells significantly attenuated caspase 3/7 activation and restored cell viability, while TXNIP overexpression significantly increased caspase 3/7 activation and cell death only in NaBu-treated cells. Moreover, TXNIP also regulated NaBu- but not 4PBA-induced H4K5 acetylation and H3K4 trimethylation, possibly by increasing WDR5 expression. Finally, we demonstrated that 4PBA induced a mitochondrial superoxide-associated cell death, while NaBu did so mainly through a TXNIP-mediated pathway. The above data might benefit the future clinic application.
丁酸钠（NaBu）和4-苯丁酸钠（4PBA）在癌症治疗方面前景广阔；然而，其潜在的分子机制尚不清楚。在此，我们表明NaBu和4PBA诱导的A549细胞死亡情况不同。NaBu处理诱导的A549细胞死亡水平显著高于4PBA。基因表达微阵列鉴定出在NaBu处理的A549细胞中超过5000个转录本发生改变（>1.5倍），而在4PBA处理的细胞中发生改变的转录本少于2000个。此外，超过100个细胞周期相关基因被NaBu强烈抑制，但被4PBA轻微抑制；只有在4PBA处理的细胞中有少数基因显著上调。基因表达通过其他实验进一步验证。此外，用这些物质处理的A549细胞在葡萄糖消耗、半胱天冬酶3/7激活和组蛋白修饰方面发生了变化，同时线粒体超氧化物生成增加。在A549细胞中，TXNIP被NaBu强烈诱导（mRNA水平为30至40倍），但仅被4PBA轻微诱导（2至5倍）。在A549细胞中通过shRNA敲低TXNIP可显著减弱半胱天冬酶3/7激活并恢复细胞活力，而TXNIP过表达仅在NaBu处理的细胞中显著增加半胱天冬酶3/7激活和细胞死亡。此外，TXNIP还调节NaBu诱导而非4PBA诱导的H4K5乙酰化和H3K4三甲基化，可能是通过增加WDR5表达。最后，我们证明4PBA诱导线粒体超氧化物相关的细胞死亡，而NaBu主要通过TXNIP介导的途径诱导细胞死亡。上述数据可能有助于未来的临床应用。
