Liao Dan, Li Tong, Ye Caiguo, Zeng Liuyan, Li Huahui, Pu Xingxiang, Ding Congcong, He Zhiwei, Huang Guo-Liang
China-American Cancer Research Institute, Dongguan Scientific Research Center, Key Laboratory for Epigenetics of Dongguan City, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong 523808, P.R. China.
Department of Gynaecology and Obstetrics, Dongguan Third People's Hospital, Affiliated Dongguan Shilong People's Hospital of Southern Medical University, Dongguan, Guangdong 523326, P.R. China.
Exp Ther Med. 2018 Feb;15(2):1712-1717. doi: 10.3892/etm.2017.5522. Epub 2017 Nov 16.
Colorectal cancer (CRC) is the third most common cancer and the fourth leading cause of cancer-associated mortalities worldwide. MicroRNAs (miRNAs/miRs) serve important roles in tumor development, progression and metastasis. miR-221 has been reported to modulate proliferation, apoptosis, cell cycle distribution and cell migration in a variety of cancers. However, the function of miR-221 in the autophagy of cancer is unclear. In the present study, the role of miR-221 in the autophagy of CRC cells was investigated and its associated target was identified. Survival analysis using The Cancer Genome Atlas data suggested that a higher expression of miR-221 was associated with poor survival in patients with CRC. A Cell Counting kit-8 assay revealed that miR-221 promoted CRC cell proliferation. Autophagy flux analyzed by microtubule-associated protein 1 light chain 3 (LC3) turnover indicated that miR-221 reduced autophagy in CRC cells using different protease inhibitors (E64d and pepstatin A; Bafilomycin A1) in nutrient-rich medium or under starvation conditions. Tumor protein 53-induced nuclear protein 1 (TP53INP1) was identified as a potential novel target of miR-221 by bioinformative prediction. The protein expression of TP53INP1 was inversely regulated by miR-221 in CRC cells. Furthermore, luciferase activity assays were performed and indicated that miR-221 may regulate the luciferase activity of wild-type TP53INP1 without interfering with the activity of mutant TP53INP1. These data suggested that miR-221 may promote the cell proliferation of CRC via the inhibition of autophagy and targeted TP53INP1.
结直肠癌（CRC）是全球第三大常见癌症，也是癌症相关死亡的第四大主要原因。微小RNA（miRNA/miR）在肿瘤发生、发展和转移中发挥重要作用。据报道，miR-221在多种癌症中调节细胞增殖、凋亡、细胞周期分布和细胞迁移。然而，miR-221在癌症自噬中的功能尚不清楚。在本研究中，研究了miR-221在CRC细胞自噬中的作用，并确定了其相关靶点。使用癌症基因组图谱数据进行的生存分析表明，miR-221的高表达与CRC患者的不良生存相关。细胞计数试剂盒-8检测显示，miR-221促进CRC细胞增殖。通过微管相关蛋白1轻链3（LC3）周转分析自噬通量表明，在营养丰富的培养基中或饥饿条件下，使用不同的蛋白酶抑制剂（E64d和胃蛋白酶抑制剂A；巴弗洛霉素A1），miR-221可降低CRC细胞中的自噬。通过生物信息学预测，肿瘤蛋白53诱导的核蛋白1（TP53INP1）被确定为miR-221的潜在新靶点。在CRC细胞中，TP53INP1的蛋白表达受到miR-221的反向调节。此外，进行了荧光素酶活性测定，结果表明miR-221可能调节野生型TP53INP1的荧光素酶活性，而不干扰突变型TP53INP1的活性。这些数据表明，miR-221可能通过抑制自噬和靶向TP53INP1来促进CRC的细胞增殖。
