MTAP Orchestrates Stemenss and 5-Fluorouracil Resistance in Liver Cancer via PRMT5/SOX2 Signaling
- VernacularTitle:MTAP通过PRMT5/SOX2通路调控肝癌干性和5-氟尿嘧啶抵抗
- Author:
Yu-Bo ZHANG
1
;
Zhao-Xiong FANG
2
;
Yun LI
1
;
Jie DONG
1
;
Xiao-Peng HONG
3
;
Hui LUO
1
Author Information
- Publication Type:Journal Article
- Keywords: MTAP; liver cancer; cancer stemness
- From: Progress in Biochemistry and Biophysics 2026;53(10):2797-2807
- CountryChina
- Language:English
- Abstract: ObjectiveMethylthioadenosine phosphorylase (MTAP) is found to be frequently deleted in malignant cancers, but the role of MTAP underlying metastasis and stemness of liver cancer remains far from clear. 5-fluorouracil (5-Fu) is clinically used in treating advanced liver cancer, however, chemoresistance is one of the major barriers impeding its efficacy. Liver cancer stem cells are considered to be the reservoir for tumor progression and chemoresistance. This study aims to explore the role of MTAP in regulating stemness and chemoresistance of 5-Fu in liver cancer. It is designed to elucidate the molecular mechanisms underlying MTAP-manipulated stemness. How MTAP influences metastasis and chemoresistance against 5-Fu in liver cancer is also elaborated. MethodsThe correlation of MTAP expression with stemness marker CD133 was evaluated by flow cytometry. Colony formation assays were conducted to analyze the tumorigenic ability. Western blot assays were applied to delineate the molecular mechanisms underlying MTAP-regulated stemness. Trans-well assays were conducted to analyze the metastatic potential of liver cancer cells.In vivo experiments were performed using subcutaneous xenograft and lung metastasis model on nude mice. Tumor size and weight were analyzed upon 5-Fu treatment. Metastatic nodules on lungs were evaluated. Immunohistochemical and TUNNEL assays were performed on slides obtained from tumor tissues. ResultsMTAP overexpression inhibited expression of CD133 and colony formation, which is further ablated by MTAP inhibitor. MTAP deprivation augmented stemness and colony formation, which is reversed by protein arginine methyltransferase 5 (PRMT5) overexpression but not its catalytically inactive counterparts. Critically, SRY-box transcription factor 2 (SOX2) was found to be a downstream regulator of MTAP/PRMT5, leading to stemness of liver cancer cells. MTAP overexpression suppressed SOX2 expression, while MTAP inhibition augmented expression of SOX2. Critically, MTAP overexpression inhibited migration and invasion of liver cancer cells. In vivo experiments in animal model found that MTAP deprivation promotes tumor growth and metastatic nodules of liver cancer. Additionally, MTAP overexpression inhibits tumor growth. Moreover, MTAP deprivation contributes to chemoresistance shown by increased tumor size and weight treated by 5-Fu. In contrast, MTAP overexpression led to further decline in tumor size and weight elicited by 5-Fu treatment. Accordingly, SOX2 was inhibited in tumor tissues after MTAP overexpression. Marker of proliferation Ki67 (Ki67) expression was dampened while apoptosis was found in MTAP-overexpressed tumor tissues. ConclusionIn this study, plethora of experimental studies collectively demonstrated that MTAP deprivation enhances stemness of liver cancer by regulating SOX2, exerting anti-cancer and chemoresistant role against 5-Fu in liver cancer. It is also worth noting that MTAP inhibition promoted metastasis of liver cancer. MTAP overexpression augmented tumor shrinking elicited by 5-Fu and SOX2 was involved in this process. These results concluded that MTAP/PRMT5/SOX2 signaling axis was involved in regulating stemness and chemoresistance of liver cancer. These findings help to exploit novel therapies by targeting stemness in MTAP-depleted liver cancer. It shed novel light on unveiling MTAP-regulated stemness in antagonizing 5-Fu treatment in liver cancer. It also adds mounting evidence to the theoretical basis for accomplishing personalized chemotherapy of liver cancer patients by targeting MTAP or its downstream PRMT5/SOX2.
