Derfi Kristina Vukovic, Vasiljevic Tea, Dragicevic Tea, Glavan Tanja Matijevic
Laboratory for Personalized Medicine, Division of Molecular Medicine, Rudjer Boskovic Institute, Bijenicka 54, Zagreb, 10000, Croatia.
Cancer Cell Int. 2024 Dec 19;24(1):412. doi: 10.1186/s12935-024-03609-6.
The development of resistance to therapy is characteristic of head and neck squamous cell carcinoma (HNSCC), the 6th most common cancer, and is often attributed to cancer stem cells (CSCs). By proteomic approach, we determined that UFMylation plays an important role in HNSCC CSCs. Because of the necessity for innovative therapeutic strategies, we explore here the therapy targeting CSCs based on mithramycin and its inhibitory effect on Sp1 transcription factor, UFMylation, and CSCs survival and stemness.
HNSCC-derived cancer cell lines Detroit 562, FaDu, and Cal27, and tumor spheres are used as a model for CSCs. Proteomic analysis identified the importance of the UFMylation pathway in CSCs which we further studied by bioinformatics, western blot, immunocytochemistry, and cytotoxicity assay.
Proteomic analysis and subsequent confirmation revealed UFSP2 and DDRGK1 were strongly expressed in tumor spheres. Bioinformatic analysis indicated high expression of UFM1 is linked with worse overall and disease-free survival, and it correlated with main EMT proteins (Zeb, Twist, and Fn) in HNSCC. UFM1 was also strongly expressed in tumor spheres compared to the adherent cells. Silencing of UFM1 reduced sphere number, size, and stemness. As Sp1 is the main transcription factor for the genes of the UFMylation system, we explored its inhibitor mithramycin, as a potential drug for CSCs inhibition. We proved mithramycin inhibits CSCs survival, induces apoptosis, and reduces UFMylation and stemness.
UFMylation is an important process in CSCs, and mithramycin, or its lesser toxic analogs, should be further explored as CSCs targeted therapy in HNSCC.
对治疗产生耐药性是头颈部鳞状细胞癌（HNSCC，第六大常见癌症）的特征，这通常归因于癌症干细胞（CSC）。通过蛋白质组学方法，我们确定泛素样修饰因子（UFMylation）在HNSCC的癌症干细胞中起重要作用。由于需要创新的治疗策略，我们在此探索基于光神霉素及其对Sp1转录因子、UFMylation以及癌症干细胞存活和干性的抑制作用来靶向癌症干细胞的治疗方法。
将源自HNSCC的癌细胞系底特律562、FaDu和Cal27以及肿瘤球用作癌症干细胞的模型。蛋白质组学分析确定了UFMylation途径在癌症干细胞中的重要性，我们通过生物信息学、蛋白质印迹、免疫细胞化学和细胞毒性试验对其进行了进一步研究。
蛋白质组学分析及后续确认显示，泛素样修饰因子特异性蛋白酶2（UFSP2）和含死亡结构域的RING样蛋白激酶1（DDRGK1）在肿瘤球中高表达。生物信息学分析表明，泛素样修饰激活酶1（UFM1）的高表达与较差的总生存期和无病生存期相关，并且它与HNSCC中的主要上皮-间质转化（EMT）蛋白（锌指E盒结合蛋白（Zeb）、 Twist相关蛋白1（Twist）和纤连蛋白（Fn））相关。与贴壁细胞相比，UFM1在肿瘤球中也高表达。UFM1的沉默减少了球体数量、大小和干性。由于Sp1是UFMylation系统基因的主要转录因子，我们探索了其抑制剂光神霉素作为一种潜在的癌症干细胞抑制药物。我们证明光神霉素可抑制癌症干细胞存活、诱导凋亡并降低UFMylation和干性。
UFMylation是癌症干细胞中的一个重要过程，光神霉素或其毒性较小的类似物应作为HNSCC中靶向癌症干细胞的治疗方法进行进一步探索。
