本研究通过分析circMFSD12在结直肠癌中的表达及对肿瘤细胞增殖、迁移、侵袭，以及对5-氟尿嘧啶（5-FU）敏感性的影响，从而分析其作为潜在治疗靶点的可行性，以期为结直肠癌治疗提供新思路。

检索公开数据库中有关结直肠癌组织、正常结肠组织和正常肠组织的人源RNA数据集（GSE172229，GSE166973，GSE147597），并筛选在结直肠癌中表达下调的circRNA，从而通过实时定量PCR（qRT-PCR）分析circMFSD12在结直肠癌细胞株中的表达水平。基于构建过表达circMFSD12的质粒并转染结直肠癌细胞株LoVo和SW620，通过EdU染色、划痕实验和Transwell实验评估其对细胞增殖、迁移和侵袭的影响。同时，通过CCK8实验和流式细胞术实验检测其对5-FU敏感性的影响，从而进一步通过生物信息学分析和miRNA pull down实验研究其潜在的分子机制。

circMFSD12在结直肠癌组织（筛选标准：logFC<-0.5）和细胞（circMFSD12表达量在人正常结肠上皮细胞NCM460为1.00±0.14，在结直肠癌细胞中分别为HCT116：0.72±0.08、LoVo：0.42±0.10、SW480：0.72±0.04和SW620：0.48±0.07）中均表达下调（P<0.05）。体外实验结果显示，过表达circMFSD12显著抑制结直肠癌细胞的增殖（LoVo：52%±5.3% vs. 22%±3.7%，P<0.001；SW620：56%±10% vs. 26%±4.0%，P<0.001）、迁移（LoVo：75%±5.5% vs. 34%±5.7%，P<0.001；SW620：54%±7.5% vs. 22%±5.6%，P<0.001）和侵袭（LoVo：104±18.6 vs. 41.7±10.2，P<0.01；SW620：86.7±16.5 vs. 34.7±4.9，P<0.01），并增强了细胞（LoVo：Control：2.5±0.7 vs. 7.4±1.0，P<0.01，5-FU：11.8±1.9 vs.28.6±1.9，P<0.001；SW620：Control：2.2±0.4 vs. 8.1±1.3，P<0.01，5-FU：10.2±1.4 vs. 23.4±2.3，P<0.001）对5-FU的敏感性。生物信息学分析及实验验证表明，通过调节靶向miR-887-3p和PPP1R12B表达，circMFSD12对结直肠癌细胞的生物行为有抑制作用。

circMFSD12调控miR-887-3p/PPP1R12B，从而显著影响结直肠癌细胞的生物行为，表明其作为新型分子标志物和潜在治疗靶点有良好的研究前景。

This study investigates the feasibility of circMFSD12 as a potential therapeutic target by analyzing its expression in colorectal cancer and its impact on tumor cell proliferation, migration, invasion, and sensitivity to 5-fluorouracil (5-FU), aiming to provide new insights for the treatment of colorectal cancer.

Human RNA datasets (GSE172229, GSE166973, GSE147597) from colorectal cancer tissues, normal colonic tissues, and normal intestinal tissues were retrieved from public databases to screen for downregulated circRNAs in colorectal cancer. The expression level of circMFSD12 in colorectal cancer cell lines was analyzed using quantitative real-time PCR (qRT-PCR). Overexpression plasmids of circMFSD12 were constructed and transfected into colorectal cancer cell lines LoVo and SW620 to evaluate their effects on cell proliferation, migration, and invasion through EdU staining, wound healing assays, and Transwell assays. Additionally, the effects on 5-FU sensitivity were assessed using CCK8 assays and flow cytometry experiments, and the potential molecular mechanisms were further investigated through bioinformatics analysis and miRNA pull-down experiments.

Data analysis indicated that circMFSD12 is downregulated in colorectal cancer tissues (selection criteria: logFC<-0.5) and cells (expression in normal colonic epithelial cells NCM460: 1.00±0.14, and in colorectal cancer cells: HCT116: 0.72±0.08, LoVo: 0.42±0.10, SW480: 0.72±0.04, SW620: 0.48±0.07) (P<0.05). In vitro experiments showed that overexpression of circMFSD12 significantly inhibited colorectal cancer cell proliferation (LoVo: 52%±5.3% vs. 22%±3.7%, P<0.001; SW620: 56%±10% vs. 26%±4.0%, P<0.001), migration (LoVo: 75%±5.5% vs. 34%±5.7%, P<0.001; SW620: 54%±7.5% vs.22%±5.6%, P<0.001), and invasion (LoVo: 104±18.6 vs. 41.7±10.2, P<0.01; SW620: 86.7±16.5 vs. 34.7±4.9, P<0.01), and enhanced cellular sensitivity to 5-FU (LoVo: Control: 2.5±0.7 vs.7.4±1.0, P<0.01, 5-FU: 11.8±1.9 vs. 28.6±1.9, P<0.001; SW620: Control: 2.2±0.4 vs. 8.1±1.3, P<0.01, 5-FU: 10.2±1.4 vs. 23.4±2.3, P<0.001). Bioinformatics analysis and experimental validation suggest that circMFSD12 suppresses colorectal cancer cell behaviors by regulating the expression of miR-887-3p and PPP1R12B.

circMFSD12 regulates miR-887-3p/PPP1R12B, significantly affecting the biological behavior of colorectal cancer cells, indicating that it has good prospects as a novel molecular biomarker and potential therapeutic target.