Duca Martina, Malagolini Nadia, Pucci Michela, Cogez Virginie, Harduin-Lepers Anne, Dall'Olio Fabio
Department of Medical and Surgical Sciences (DIMEC), General Pathology Building, University of Bologna, Bologna, Italy.
Unité de Glycobiologie Structurale et Fonctionnelle, CNRS, UMR 8576, UGSF, Univ. Lille, 59000, Lille, France.
Sci Rep. 2025 Jan 13;15(1):1821. doi: 10.1038/s41598-025-85450-z.
The β1,4-N-acetylgalactosaminyltransferase 2 (B4GALNT2) which synthesizes the histo-blood group antigen Sd is highly expressed by normal colon, but it is dramatically down-regulated in colorectal cancer (CRC). High B4GALNT2 expression in CRC tissues is a marker of longer survival. The molecular bases of B4GALNT2 inhibition in CRC are largely obscure. A key role may be played by transcription factors and miRNA. Through an in silico analysis of The Cancer Genome Atlas and of the Cancer Cell Line Encyclopedia, we identified the transcription factors FOXD1, FOXF2 and PGR as well as mir-204-5p as potential inhibitory agents. Their transient transfection in the cell line GP2d, whose B4GALNT2 is closer to that of a normal mucosa, confirmed their inhibitory activity with a crucial role for FOXD1. The latter inhibited B4GALNT2 also in the middle B4GALNT2 expresser cell line Caco2. Deletion experiments of the putative FOXD1 binding sites in the ~ 2800 bp sequence upstream of the B4GALNT2 transcriptional start site cloned in frame with the luciferase reporter gene, confirmed the regulatory role of FOXD1. Finally, FOXD1 knock down in the non-B4GALNT2 expresser cell line SW948 stimulated B4GALNT2. Thus, FOXD1 and miR-204-5p emerged as crucial new player of B4GALNT2 down-regulation in CRC.
合成组织血型抗原Sd的β1,4-N-乙酰半乳糖胺基转移酶2（B4GALNT2）在正常结肠中高表达，但在结直肠癌（CRC）中显著下调。CRC组织中高B4GALNT2表达是生存期较长的一个标志物。CRC中B4GALNT2受抑制的分子基础很大程度上尚不清楚。转录因子和微小RNA可能起关键作用。通过对癌症基因组图谱和癌细胞系百科全书的计算机分析，我们确定转录因子FOXD1、FOXF2和PGR以及mir-204-5p为潜在抑制剂。它们在细胞系GP2d（其B4GALNT2更接近正常黏膜的B4GALNT2）中的瞬时转染证实了它们的抑制活性，其中FOXD1起关键作用。FOXD1在中等B4GALNT2表达的细胞系Caco2中也抑制B4GALNT2。对与荧光素酶报告基因框内克隆的B4GALNT2转录起始位点上游约2800 bp序列中假定的FOXD1结合位点进行缺失实验，证实了FOXD1的调节作用。最后，在非B4GALNT2表达的细胞系SW948中敲低FOXD1可刺激B4GALNT2。因此，FOXD1和miR-204-5p成为CRC中B4GALNT2下调的关键新因子。
