Mechanistic study of Liquiritigenin inhibiting bladder cancer cell proliferation and migration by regulating STING1

Background: Bladder cancer (BLCA) is the most common malignant tumor in the urinary system, with a significantly higher incidence in men than in women, severely impacting quality of life. The STING1 gene (stimulator of interferon genes 1) plays a critical role in innate immunity by recognizing abnormal DNA and activating immune signaling pathways, promoting the expression of type I interferons and pro-inflammatory cytokines, thereby enhancing anti-tumor immune responses. Liquiritigenin (LQG), a flavonoid compound extracted from licorice, exhibits anti-inflammatory, antioxidant, and anti-cancer properties, capable of inhibiting tumor cell proliferation and invasion while regulating autophagy. This study aims to evaluate the role of LQG in regulating the STING1 gene and its anti-cancer mechanisms in bladder cancer. Methods: This study employed a multidimensional approach, combining bioinformatics analysis with both in vitro and in vivo experimental validation. Bioinformatics was utilized to assess the expression, function, and immune-related analyses of the STING1 gene. In vitro experiments included CCK-8 assays and colony formation assays to evaluate cell proliferation; Transwell migration assays and wound healing assays to assess migratory capacity; flow cytometry to analyze apoptosis; and immunofluorescence to observe the accumulation of autophagosomes. Additionally, molecular docking analysis was conducted to explore the interaction between LQG and the STING protein, while Western blotting was used to elucidate key molecular pathways. In vivo studies employed a mouse xenograft tumor model to systematically evaluate the anti-tumor effects and safety of LQG. Results: The results showed that STING1 expression was significantly lower in bladder cancer tissues compared to normal tissues. Functional enrichment analysis indicated a close relationship between STING1 and immune response regulation. High STING1 expression was positively associated with different types of immune cells and important immune checkpoints. Analysis of immunotherapy indicated that high STING1 expression was associated with favorable clinical responses. Molecular docking confirmed that LQG directly targets the STING protein. Experimental results demonstrated that LQG inhibits tumor cell survival by targeting STING and blocking autophagic flux. Additionally, LQG downregulated the expression of MMP2 and MMP9, inhibiting migration and invasion, while enhancing apoptosis by modulating Bcl-2, Bax, and caspase-3 levels. Conclusion: These findings underscore the critical role of STING1 in the immunobiology of bladder cancer, indicating its potential as a therapeutic target and biomarker for immunotherapy. The novel STING agonist LQG has multiple anti-tumor effects, including the modulation of apoptosis, inhibition of invasion, and enhancement of immune responses. This paves the way for future STING-targeted therapies in bladder cancer treatment.