Pan-cancer analysis to identify molecules interacting with CasL-Like 2 to promote angiogenesis via mTOR/HIF1A/VEGFA pathway in hypoxia tumor environment

e15002 Background: Cytoskeleton dynamics generate power for diverse motile and morphogenetic processes in eukaryotic cells. Aberrant actin dynamics are closely associated with pathological conditions and implicated in the occurrence of various tumors. The underlying mechanisms remain to be explored. This study aims to identify a unique redox enzyme, Molecules Interacting with CasL-Like 2 (MICALL2), as a regulator of actin filaments during tumorigenesis and to evaluate its potential value in predicting drug sensitivity to anti-angiogenesis agents. Methods: First, bioinformatic analysis was used to demonstrate MICALL2 expression level across distinct cancers and its relationship with clinical characteristics from TCGA and CPTAC databases. Functional enrichment analysis and whole-mountin situ hybridization were performed. Gene correlation analysis and IHC were used to detect the correlation between MICALL2 and HIF family. Next, chosen kidney renal clear cell carcinoma (KIRC) as a research object, the location of MICALL2 and actin was determined by immunofluorescence. IHC on MICALL2, HIF1A, VEGFA, CD31, CD34 of 44 clinical KIRC tissue samples was performed. The role of MICALL2 in proliferation, hypoxia and angiogenesis of KIRC cells was investigated using EDU staining, CCK-8 assay, ROS analysis, flow cytometry, and tubule formation assays. The effect of MICALL2 on the mTOR-related signal pathway was evaluated by western blot. Last, drug sensitivity analysis was obtained from the GDSC, CTRP, and PRISM databases to reveal the relationship between MICALL2 and anti-angiogenesis agents and cytoskeleton-regulating drugs. Results: MICALL2 expression was elevated in most cancers and correlated with poor survival outcomes. Pan-cancer analysis demonstrated that MICALL2 was co-expressed with HIF family members and strongly linked to angiogenesis pathway. Interfering the translation of MICALL2 during zebrafish embryogenesis resulted in defective caudal vein plexus morphogenesis. Additionally, KIRC patients with high MICALL2 expression displayed enhanced HIF1A expression and increased CD34-labeled neovascularization. In KIRC cells, MICALL2 was found co-located with F-actin. MICALL2 overexpressed KIRC cells exhibited more aggressive behaviors, with the tumor microenvironment remodeling to a more hypoxia condition. Up-regulation of MICALL2 promoted tumor angiogenesis via activating a novel mTOR/HIF1A/VEGFA pathway. Furthermore, tumor patients with high MICALL2 expression were more likely to be resistant to anti-angiogenesis agents and microtubule depolymerization inhibitors, but sensitive to actin polymerization inhibitors. Conclusions: Our results suggest that MICALL2 plays a crucial role in tumor angiogenesis and may be a potential predictor of anti-angiogenic agent sensitivity across multiple cancers.