Guan‐tai Ni

Multi‐Omics Analysis Reveals That the MAZ / HDGF Regulatory Axis Drives High‐Grade Serous Ovarian Cancer Progression by Modulating Glycolysis and M2 Macrophage Polarization

ABSTRACT Super‐enhancers (SEs) are large clusters of enhancers that drive high‐level expression of genes critical for normal development and tumorigenesis. However, their precise roles in high‐grade serous ovarian carcinoma (HGSOC) remain unclear. This study integrated SE‐derived regulatory networks with proteomic profiles to identify key pro‐tumorigenic signaling in HGSOC progression. Weighted gene co‐expression network analysis (WGCNA) and machine learning were used to screen SE‐driven core oncoproteins. The influence on cell phenotypes was evaluated by detecting invasion, proliferation, apoptosis, glucose consumption, lactate generation, and tube formation. M2 macrophage polarization was assessed by detecting CD163 + cell proportion and TGF‐β1 and IL‐10 secretion. The MAZ/HDGF interaction was confirmed by luciferase and ChIP‐qPCR assays. Xenograft studies were used to evaluate the in vivo function. HDGF was overexpressed and was identified as a core SE‐driven oncoprotein in HGSOC. Silencing of HDGF inhibited the invasion, proliferation, and glycolysis of HGSOC cells, promoted their apoptosis, and attenuated HUVEC tube formation and M2 macrophage polarization. Mechanistically, MAZ transcriptionally activated HDGF through promoter binding. Moreover, HDGF re‐expression counteracted the suppressive effects of MAZ knockdown on HGSOC cell malignant behaviors, HUVEC tube formation, M2 macrophage polarization, and the growth of xenograft tumors. In conclusion, our study unveils the MAZ/HDGF axis as a novel SE‐mediated oncogenic pathway in HGSOC, providing previously unrecognized insights into SE‐driven oncogenesis and highlighting potential targets for HGSOC treatment.

HIF-1α Regulated WTAP Overexpression Promoting the Warburg Effect of Ovarian Cancer by m6A-Dependent Manner

N6-methyladenosine (m6A) RNA methylation has been determined to execute crucial functions in tumorigenesis and cancer development. WT1-associated protein (WTAP) has an important “writer” role in m6A modification, and it is also a nuclear protein that colocalizes with splicing factors and plays a critical role in cell function and cancer progression. However, little is known about the role of WTAP in ovarian cancer (OC) and its mechanisms. In this study, we found for the first time that hypoxia-inducible factor (HIF)-1α could positively regulate increased expression of WTAP under hypoxia. And further results revealed that WTAP expression was closely associated with the clinicopathological features of OC, and high expression of WTAP predicted low survival rate in patients with OC. In addition, cell proliferation and invasive capacity were significantly reduced after knockdown of WTAP expression in OC cells. However, cell proliferation and invasive ability were significantly enhanced after overexpression of WTAP. Additionally, we find that WTAP interacts with DGCR8 (a crucial chip protein) to regulate the expression of microRNA-200 (miR-200) in an m6A-dependent way. Further experiments showed that the key glycolysis enzyme HK2 could be positively regulated by miR-200, which significantly affected the intracellular Warburg effect. In conclusion, this is considered uncovered that upregulation of WTAP expression by HIF-1α intercedes with miRNA processing, accelerates the Warburg impact, and advances the event and advancement of tumor, thus giving a novel viewpoint on m6A adjustment in OC movement.

FUS-stabilized USP7 facilitates the bevacizumab resistance of ovarian cancer through deubiquitinating PTK2

The emergence of drug resistance brings new challenges to the clinical management of ovarian cancer (OC) patients. This study aimed to explore the role and mechanism of ubiquitin-specific peptidase 7 (USP7) on the bevacizumab resistance of OC. The mRNA levels of USP7 and protein tyrosine kinase 2 (PTK2) were measured using quantitative real-time polymerase chain reaction. Western blot analysis was used for detecting the protein levels of USP7, PTK2 and fused in sarcoma (FUS). Cell resistance, proliferation, apoptosis, invasion and angiogenesis were determined by cell counting kit 8 assay, colony formation assay, flow cytometry, transwell assay and tube formation assay. Glucose consumption, lactate production, and ATP/ADP ratio were used to evaluate glycolysis. The interactions between USP7 and PTK2/FUS were detected by co-immunoprecipitation assay. Mice xenograft model was also constructed to explore USP7 roles in vivo. USP7 was upregulated in OC tissues and bevacizumab-resistant cells. USP7 knockdown or its inhibitor P22077 inhibited the bevacizumab resistance of OC cells via suppressing cell growth, metastasis, angiogenesis and glycolysis. USP7 stabilized PTK2 protein expression via deubiquitinating. PTK2 overexpression reversed the effect of USP7 knockdown on the bevacizumab resistance of OC cells. Besides, FUS stabilized USP7 mRNA to regulate its protein level, and it could affect PTK2 expression by mediating USP7. USP7 knockdown enhanced the sensitivity of OC tumors to bevacizumab in vivo. FUS-stabilized USP7 enhanced the bevacizumab resistance of OC by deubiquitinating PTK2, providing a new idea for overcoming bevacizumab resistance in OC.