Circular RNA (circRNA), a novel class of non-coding RNA, has been reported in various diseases, especially in tumors. However, the key signatures of circRNA-competitive endogenous RNA (ceRNA) network are largely unclear in colorectal cancer (CRC). We first characterized circRNAs profile by using circRNA-seq analysis from real-word dataset. The expression level of hsa_circ_0066351 in CRC tissues and cell lines was detected by quantitative real-time PCR. Then, cell proliferation assay was used to confirm the proliferation function of hsa_circ_0066351. Next, Cytoscape was used to construct circRNA–miRNA–mRNA networks. Last but not least, the landscape of hsa_circ_0066351–miRNA–mRNA in CRC had been investigated in the bulk tissue RNA-Seq level and single-cell Seq level. We proved that hsa_circ_0066351 was significantly downregulated in CRC cell lines and tissues (P < 0.001), and was negatively associated with distant metastasis (P < 0.01). Significantly, the expression of hsa_circ_0066351 was associated with better survival in patients with CRC. Function assays showed that hsa_circ_0066351 could inhibit CRC cells proliferation. In addition, a ceRNA network, including hsa_circ_0066351, two miRNAs, and ten mRNAs, was constructed. Our analyses showed that these ten mRNAs were consistently downregulated in pan-cancer and enriched in tumor suppressive function. A risk score model constructed by these ten downstream genes also indicated that they were related to the prognosis and immune response in CRC. In conclusion, we demonstrated that a novel circRNA (hsa_circ_0066351) inhibited CRC proliferation, and revealed a potential prognostic and immunotherapeutic biomarker in CRC.

中文翻译：

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Hsa_Circ_0066351 作为结直肠癌的预后和免疫治疗生物标志物

环状 RNA (circRNA) 是一类新型的非编码 RNA，已在多种疾病，尤其是肿瘤中得到报道。然而，circRNA 竞争性内源性 RNA (ceRNA) 网络的关键特征在结直肠癌 (CRC) 中尚不清楚。我们首先通过使用来自真实数据集的 circRNA-seq 分析来表征 circRNAs 配置文件。采用实时定量PCR检测CRC组织和细胞系中hsa_circ_0066351的表达水平。然后，使用细胞增殖试验来确认hsa_circ_0066351的增殖功能。接下来，Cytoscape 用于构建 circRNA-miRNA-mRNA 网络。最后但并非最不重要的一点是，已经在大量组织 RNA-Seq 水平和单细胞 Seq 水平上研究了 hsa_circ_0066351–miRNA–mRNA 在 CRC 中的景观。我们证明 hsa_circ_0066351 在 CRC 细胞系和组织中显着下调 (P < 0.001)，并且与远处转移呈负相关 (P < 0.01)。值得注意的是，hsa_circ_0066351 的表达与 CRC 患者更好的生存相关。功能测定表明 hsa_circ_0066351 可以抑制 CRC 细胞增殖。此外，还构建了一个ceRNA网络，包括hsa_circ_0066351、两个miRNA和十个mRNA。我们的分析表明，这十种 mRNA 在泛癌中持续下调并富集肿瘤抑制功能。由这十个下游基因构建的风险评分模型也表明它们与 CRC 的预后和免疫反应有关。总之，我们证明了一种新的 circRNA (hsa_circ_0066351) 抑制了 CRC 增殖，