Identification and validation of immune-related hub genes based on machine learning in prostate cancer and AOX1 is an oxidative stress-related biomarker

Aldehyde oxidase 1 promotes gallbladder carcinogenesis through ROS-mediated activation of the Wnt/β-catenin pathway

BACKGROUND

Aldehyde oxidase 1 (AOX1) is associated with various pathophysiological processes, including cancer. Specifically, AOX1 has been demonstrated to have a close relationship with the progression of certain cancers. However, the expression, function, and mechanisms of action of AOX1 in gallbladder cancer (GBC) remain unclear.

METHODS

Utilizing immunohistochemistry, the study quantified the prevalence of AOX1 within tissues of gallbladder carcinoma and those of the surrounding non-cancerous regions. In vitro assays using gallbladder carcinoma cell lines with modulated AOX1 expression levels were performed to assess the protein's role in cell proliferation, migration, and invasion. Furthermore, flow cytometry techniques were harnessed to determine the influence of AOX1 on the content of reactive oxygen species (ROS) in these cells. Additionally, the expression of epithelial-mesenchymal transition (EMT) markers and the Wnt/β-catenin signaling pathway markersin cells with varied AOX1 expression, detected through Western blot analyses. An in vivo xenograft model involving athymic mice was implemented to explore the influence of AOX1 on gallbladder tumor growth, with Western blot analysis applied to measure EMT marker expression in the resulting tumours.

RESULTS

Elevated AOX1 protein levels have been observed in gallbladder carcinoma tissues, with such upregulation linked to a negative prognostic outlook for patients. In vitro analyses demonstrate that enhanced AOX1 expression facilitates gallbladder carcinoma cell proliferation, migration, and invasion, while AOX1 suppression yields an inhibitory effect on these cellular behaviors. Western blot results reveal an inverse relationship between AOX1 and E-cadherin levels, yet was positively correlation with N-cadherin, Vimentin, and Snail within both gallbladder cancer cells and in vivo xenograft tumours. Further mechanistic investigation indicates that AOX1 elevation augments reactive oxygen species (ROS) production and initiates the Wnt/β-catenin signaling pathway in these cells. The application of N-acetylcysteine (NAC) and/or KY1797K attenuates the proliferative, migratory, and invasive enhancements imparted by AOX1 overexpression and reinforces these effects when AOX1 is silenced-achieved through ROS mitigation and the obstruction of the Wnt/β-catenin pathway. In vivo studies corroborate these findings, showing AOX1 overexpression to amplify xenograft tumor growth and mesenchymal marker expression, whereas AOX1 interference did the opposite.

CONCLUSIONS

The study indicates that AOX1 functions as a carcinogenic factor in gallbladder carcinoma, enhancing cell proliferation, migration, invasion, and the EMT. These effects are driven by the activation of the Wnt/β-catenin pathway mediated by reactive oxygen species (ROS). Therefore,AOX1 presents potential as a valuable prognostic and diagnostic marker as well as a target for therapeutic intervention in the gallbladder cancer.

ACOX2 Serves as a Favorable Indicator Related to Lipid Metabolism and Oxidative Stress for Biochemical Recurrence in Prostate Cancer

Given the heterogeneity of tumors, there is an urgent need for accurate prognostic parameters in prostate cancer (PCa) patients. Lipid metabolism (LM) reprogramming and oxidative stress (OS) play a vital role in the progression of PCa. In this work, we identified five LM-OS-related genes (including ACOX2, PPRAGC1A, PTGS1, PTGS2, and HAO1) associated with the biochemical recurrence (BCR) of PCa. Subsequently, a prognostic signature was established based on these five genes. Kaplan-Meier survival estimates, receiver operating characteristic curves, and relationship analysis between risk score and clinical characters were applied to measure the robustness of the signature in an external cohort. A nomogram of risk score combined with clinical characteristics was constructed for clinical application. Functional enrichment analysis suggested that the underlying mechanism related to the signature included the calcium signaling, lipid transport, and cell cycle signaling pathways. Furthermore, WEE1 inhibitor was identified as a potential agent related to the cell cycle for high-risk patients. The mRNA expression and the prognostic value of the five genes were determined, and ACOX2 was identified as the key gene related to the prognostic signature. The protein expression of ACOX2 was measured in a prostate tissue microarray through an immunohistochemistry assay, confirming the bioinformatics results. By constructing the ACOX2-overexpressing PCa cell lines PC-3 and 22Rv1, the biological function of PCa cells was investigated. The cell viability, colony formation, migration, and invasion ability of PCa cell lines overexpressing ACOX2 were hindered. Decreased cellular lipid content and elevated cellular ROS content were observed in ACOX2-overexpressing PCa cell lines with reduced G2/M phases. In conclusion, this work presents the first prognostic signature specifically focused on LM-OS for PCa. ACOX2 could serve as a favorable indicator for the BCR in PCa. Further experiments are required to identify the potential underlying mechanism.