Department of Gastroenterology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, No. 158 Shangtang Road, Hangzhou, Zhejiang, China.
The Medical College of QingDao University, No. 308 Ningxia Road, Shinan District, Qingdao, Shandong, China.
Cell Death Dis. 2021 May 4;12(5):443. doi: 10.1038/s41419-021-03714-8.
Dysregulation of circular RNA (circRNA) expression is involved in the progression of cancer. Here, we aimed to study the potential function of hsa_circ_0006401 in colorectal cancer (CRC). CircRNA hsa_circ_0006401 expression levels in CRC and adjacent nontumor tissues were analyzed by real-time quantitative PCR (qRT-PCR) and circRNA in situ hybridization (RNA-ISH). Then, CRC cell proliferation was assessed by cell counting. Wound-healing and transwell assays were utilized to detect the effect of hsa_circ_0006401 on CRC migration. A circRNA-ORF construct was created, and a specific antibody against the splice junction of hsa_circ_0006401 was prepared. Finally, the proteins directly binding to hsa_circ_0006401 peptides were identified by immunoprecipitation combined with mass spectrometry. In our study, we found hsa_circ_0006401 was closely related to CRC metastasis and exhibited upregulated expression in metastatic CRC tissue samples. Proliferation and migration were inhibited in vitro when hsa_circ_0006401 expression was silenced. Downregulation of hsa_circ_0006401 expression decreased CRC proliferation and liver metastasis in vivo. A 198-aa peptide was encoded by sequences of the splice junction absent from col6a3. Hsa_circ_0006401 promoted CRC proliferation and migration by encoding the hsa_circ_0006401 peptide. Hsa_circ_0006401 peptides decreased the mRNA and protein level of the host gene col6a3 by promoting col6a3 mRNA stabilation. In conclusion, our study revealed that circRNAs generated from col6a3 that contain an open-reading frame (ORF) encode a novel 198-aa functional peptide and hsa_circ_0006401 peptides promote stability of the host gene col6a3 mRNA to promote CRC proliferation and metastasis.
环状 RNA（circRNA）表达失调参与癌症的进展。在这里，我们旨在研究 hsa_circ_0006401 在结直肠癌（CRC）中的潜在功能。通过实时定量 PCR（qRT-PCR）和环状 RNA 原位杂交（RNA-ISH）分析 CRC 及相邻非肿瘤组织中 circRNA hsa_circ_0006401 的表达水平。然后，通过细胞计数评估 CRC 细胞的增殖。利用划痕愈合和 Transwell 测定法检测 hsa_circ_0006401 对 CRC 迁移的影响。构建了 circRNA-ORF 构建体，并制备了针对 hsa_circ_0006401 剪接接头的特异性抗体。最后，通过免疫沉淀结合质谱鉴定与 hsa_circ_0006401 肽直接结合的蛋白质。在我们的研究中，我们发现 hsa_circ_0006401 与 CRC 转移密切相关，在转移性 CRC 组织样本中表达上调。当沉默 hsa_circ_0006401 的表达时，体外增殖和迁移受到抑制。体内下调 hsa_circ_0006401 的表达降低了 CRC 的增殖和肝转移。从 col6a3 中不存在剪接的序列编码了一个 198-aa 肽。Hsa_circ_0006401 通过编码 hsa_circ_0006401 肽促进 CRC 增殖和迁移。Hsa_circ_0006401 肽通过促进 col6a3 mRNA 稳定来降低宿主基因 col6a3 的 mRNA 和蛋白水平。总之，我们的研究揭示了来自 col6a3 的环状 RNA 含有开放阅读框（ORF），可编码一种新型的 198-aa 功能肽，hsa_circ_0006401 肽促进宿主基因 col6a3 mRNA 的稳定性，从而促进 CRC 的增殖和转移。
