Tumor-suppressive miR-4732-3p is sorted into fucosylated exosome by hnRNPK to avoid the inhibition of lung cancer progression

• Published in: Journal of experimental & clinical cancer research 2024-04, Vol.43 (1), p.123-123, Article 123
• Main Authors: Zhuang, Wanzhen, Liu, Chengxiu, Hong, Yilin, Zheng, Yue, Huang, Minjian, Tang, Haijun, Zhao, Lilan, Huang, Zhixin, Tu, Mingshu, Yu, Lili, Chen, Jianlin, Zhang, Yi, Chen, Xiongfeng, Lin, Fan, Gao, Qi, Yu, Chundong, Huang, Yi
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Biomarkers; Biomarkers, Tumor - analysis; Biomarkers, Tumor - blood; Cancer; Carcinoma, Non-Small-Cell Lung - metabolism; Carcinoma, Non-Small-Cell Lung - pathology; Cell cycle; Cell Cycle Checkpoints; Cell division; Cell Proliferation; Development and progression; Disease Progression; Down-Regulation; Exosome escape; Exosomes - metabolism; Fluorescence; Fucose - metabolism; Fucosylated exosome; Genes, Tumor Suppressor; Glycosylation; Heterogeneous-Nuclear Ribonucleoprotein K - metabolism; hnRNPK; Humans; Kinases; Lectins; Lung cancer; Lung cancer, Non-small cell; Lung Neoplasms - metabolism; Lung Neoplasms - pathology; Medical prognosis; Membrane Proteins - analysis; Membrane Proteins - genetics; Membrane Proteins - metabolism; MFSD12; Mice; Mice, Nude; MicroRNA; MicroRNAs; MicroRNAs - blood; MicroRNAs - metabolism; miR-4732-3p; Prevention; Prognosis; Signal Transduction; Tumors
• ISSN: 1756-9966; 0392-9078; 1756-9966
• DOI: 10.1186/s13046-024-03048-1

Aberrant fucosylation observed in cancer cells contributes to an augmented release of fucosylated exosomes into the bloodstream, where miRNAs including miR-4732-3p hold promise as potential tumor biomarkers in our pilot study. However, the mechanisms underlying the sorting of miR-4732-3p into fucosylated exosomes during lung cancer progression remain poorly understood. A fucose-captured strategy based on lentil lectin-magnetic beads was utilized to isolate fucosylated exosomes and evaluate the efficiency for capturing tumor-derived exosomes using nanoparticle tracking analysis (NTA). Fluorescence in situ hybridization (FISH) and qRT-PCR were performed to determine the levels of miR-4732-3p in non-small cell lung cancer (NSCLC) tissue samples. A co-culture system was established to assess the release of miRNA via exosomes from NSCLC cells. RNA immunoprecipitation (RIP) and miRNA pull-down were applied to validate the interaction between miR-4732-3p and heterogeneous nuclear ribonucleoprotein K (hnRNPK) protein. Cell functional assays, cell derived xenograft, dual-luciferase reporter experiments, and western blot were applied to examine the effects of miR-4732-3p on MFSD12 and its downstream signaling pathways, and the impact of hnRNPK in NSCLC. We enriched exosomes derived from NSCLC cells using the fucose-captured strategy and detected a significant upregulation of miR-4732-3p in fucosylated exosomes present in the serum, while its expression declined in NSCLC tissues. miR-4732-3p functioned as a tumor suppressor in NSCLC by targeting 3'UTR of MFSD12, thereby inhibiting AKT/p21 signaling pathway to induce cell cycle arrest in G2/M phase. NSCLC cells preferentially released miR-4732-3p via exosomes instead of retaining them intracellularly, which was facilitated by the interaction of miR-4732-3p with hnRNPK protein for selective sorting into fucosylated exosomes. Moreover, knockdown of hnRNPK suppressed NSCLC cell proliferation, with the elevated levels of miR-4732-3p in NSCLC tissues but the decreased expression in serum fucosylated exosomes. NSCLC cells escape suppressive effects of miR-4732-3p through hnRNPK-mediated sorting of them into fucosylated exosomes, thus supporting cell malignant properties and promoting NSCLC progression. Our study provides a promising biomarker for NSCLC and opens a novel avenue for NSCLC therapy by targeting hnRNPK to prevent the "exosome escape" of tumor-suppressive miR-4732-3p from NSCLC cells.