Shaohua Xu

Hsa_circ_0013561 promotes epithelial-mesenchymal transition and tumor progression by regulating ANXA2 via miR-23b-3p in ovarian cancer

AbstractOur preliminary experiment discovered that hsa_circ_0013561 was aberrantly expressed in OC. However, the underlying mechanism is unclear. The expression of hsa_circ_0013561 in OC cells and tissues was detected by RT-qPCR and fluorescence in situ hybridization. The effects of hsa_circ_0013561 on the proliferation and metastasis of OC were explored by functional experiments such as cell counting kit-8, transwell, and tumor xenograft models. To mechanistically understand the regulatory role of hsa_circ_0013561, bioinformatics analysis, Western blot, luciferase reporter assay, and a series of rescue experiments were applied. We found that the hsa_circ_0013561 expression was elevated in OC cells and tissues, and was correlated with metastasis formation. Downregulation of hsa_circ_0013561 suppressed the proliferation and migration of OC cells both in vitro and in vivo. Regarding the interactions of hsa_circ_0013561, the luciferase reporter assay verified that miR-23b-3p and Annexin A2 (ANXA2) were its downstream targets. MiR-23b-3p inhibition or ANXA2 overexpression reversed OC cell proliferation, migration, and epithelial-mesenchymal transition (EMT) post-hsa_circ_0013561 silencing. Moreover, ANXA2 overexpression also reversed OC cell migration, proliferation, and EMT after miR-23b-3p upregulation. Our data suggest that hsa_circ_0013561 increases the expression of ANXA2 by regulating miR-23b-3p competitively, resulting in EMT and metastasis of OC. Thus, hsa_circ_0013561 may serve as a novel oncogenic biomarker for OC progression.

NAD+ Metabolism-Mediated SURF4-STING Axis Enhances T-Cell Anti-Tumor Effects in the Ovarian Cancer Microenvironment

Abstract The anti-tumor function of T cells in the ovarian cancer (OC) microenvironment influences the prognosis of OC. Previous studies have indicated that metabolic competition among microenvironmental cells regulates the function of immune cells. Recent research has shown that NAD+ metabolism plays a significant role in modulating immune cell activity, and increasing NAD+ levels is a promising therapeutic strategy to enhance the effector functions of immune cells. However, the regulatory mechanisms of NAD+ metabolism on the anti-tumor function of T cells in the OC microenvironment remain unclear. This study found that exogenous supplementation of NAM to increase NAD+ levels in T cells significantly activates the endogenous p-STING axis and downstream interferon signaling within T cells, thereby enhancing T cell activation and anti-tumor effects. Concurrently, we discovered that elevated NAD+ levels promote the retention of STING on the Golgi apparatus. Mechanistically, we elucidated that the increase in NAD+ levels mediated by NAM downregulates the expression of SURF4 protein through ubiquitination and degradation, subsequently activating the p-STING axis in T cells. Furthermore, exogenous NAM supplementation can further enhance the activation of the T cell STING axis by PARP inhibitor (PARPi)-treated OC cells, and the combination of PARPi and NAM significantly augments the anti-tumor function of T cells, inhibiting the progression of OC. Our findings provide a molecular basis for the regulation of T cell anti-tumor function by NAD+, highlighting the potential strategy of targeting T cell metabolic reprogramming for the treatment of OC.

LncRNA IL21-AS1 facilitates tumour progression by enhancing CD24-induced phagocytosis inhibition and tumorigenesis in ovarian cancer

AbstractCD24 is overexpressed in various tumours and considered a regulator of cell migration, invasion, and proliferation. Recent studies have found that CD24 on ovarian cancer (OC) and triple-negative breast cancer cells interacts with the inhibitory receptor sialic-acid-binding Ig-like lectin 10 (Siglec-10) on tumour-associated macrophages (TAMs) to inhibit phagocytosis by macrophages. Because of its multiple roles in regulating the immune response and tumorigenesis, CD24 is a very promising therapeutic target. However, the regulatory mechanism of CD24 in OC remains unclear. Here, we found that the long noncoding RNA (lncRNA) IL21-AS1, which was upregulated in OC, inhibited macrophage-mediated phagocytosis and promoted OC cell proliferation and apoptosis inhibition. More importantly, after IL21-AS1 knockdown, a significant survival advantage was observed in mice engrafted with tumours. Mechanistically, we identified IL21-AS1 as a hypoxia-induced lncRNA. Moreover, IL21-AS1 increased HIF1α-induced CD24 expression under hypoxic conditions. In parallel, we found that IL21-AS1 acted as a competing endogenous RNA (ceRNA) for miR-561-5p to regulate CD24 expression. Finally, IL21-AS1 increased CD24 expression in OC and facilitated OC progression. Our findings provide a molecular basis for the regulation of CD24, thus highlighting a potential strategy for targeted treatment of OC.