Evading host immunity killing is a critical step for virus survival. Inhibiting viral immune escape is crucial for the treatment of viral diseases. Serine/threonine kinase 39 (STK39) was reported to play an essential role in ion homeostasis. However, its potential role and mechanism in viral infection remain unknown. In this study, we found that viral infection promoted STK39 expression. Consequently, overexpressed STK39 inhibited the phosphorylation of interferon regulatory factor 3 (IRF3) and the production of type I interferon, which led to viral replication and immune escape. Genetic ablation or pharmacological inhibition of STK39 significantly protected mice from viral infection. Mechanistically, mass spectrometry and immunoprecipitation assays identified that STK39 interacted with PPP2R1A (a scaffold subunit of protein phosphatase 2A (PP2A)) in a kinase activity-dependent manner. This interaction inhibited DDB1 and CUL4 associated factor 1 (DCAF1)-mediated PPP2R1A degradation, maintained the stabilization and phosphatase activity of PP2A, which, in turn, suppressed the phosphorylation of IRF3, decreased the production of type I interferon, and then strengthened viral replication. Thus, our study provides a novel theoretical basis for viral immune escape, and STK39 may be a potential therapeutic target for viral infectious diseases.

BACKGROUND:With the innovation of examination technique,the number of patients with spinal metastases in different stages is increasing year by year.Percutaneous vertebroplasty is an important treatment for spinal metastases;however,there is no report on the biomechanical effect in different stages and different activities after operation. OBJECTIVE:To simulate thoracic T10 bone stress and displacement of the different locations of the tumor metastasis based on the three-dimensional finite element model. METHODS:According to thoracic three-dimensional CT images of a 30-year-old healthy male,Mimics software was used to construct a three-dimensional geometric model of thoracic vertebrae(T9-T11),including ribs,ligaments and intervertebral discs.Three-dimensional models of T9-T11 vertebral bodies and different parts of the posterior thoracic vertebrae invaded by thoracic metastatic tumors were simulated,including the control group with intact vertebral structure,unilateral metastasis involving the vertebral body area(experimental group 1),unilateral metastasis involving the vertebral body and pedicle area(experimental group 2),unilateral metastasis involving the vertebral body,pedicle and transverse process area(experimental group 3),and bilateral metastasis involving the vertebral body,pedicle and transverse process area(experimental group 4).Abaqus software was used to create a three-dimensional finite element model.The von Mises stress distribution and the displacement of the model were analyzed under the loading condition,buckling condition,extension condition,and rotation condition. RESULTS AND CONCLUSION:(1)In the study of the maximum total displacement of loading points in different experimental groups under loading,flexion,extension,and rotation conditions,with the increase of metastatic tumor invasion site and invasion surface,the total displacement of loading points increased,and the overall stiffness decreased,especially the total displacement of loading points in experimental group 4 was the largest.(2)Under flexion condition,the maximum Von Mises stress value increased significantly after vertebral body and pedicle destruction,while the maximum Von Mises stress value was almost unchanged when the thoracocostal joint destruction was added.(3)On the basis of finite element analysis and simulation of bone tumor model,the elements in the bone cement region were set as a single set,and the bone cement region was set as the corresponding material properties to simulate bone cement filling.The results showed that the maximum total displacement under loading,flexion,extension,and rotation conditions was less than that of each experimental group.(4)The maximum stress values of the simulated percutaneous vertebroplasty patients in the loading,flexion,extension and rotation conditions were significantly lower than those of the femoral model.(5)It is concluded that the three-dimensional finite element model based on thoracic T9-T11 conducive to the biomechanics characteristics of thoracic vertebrae tumor metastasis,and on the basis of the thoracic vertebrae tumor metastasis model can accurately simulate load point after percutaneous vertebral body under different conditions of total displacement and the maximum Von Mises stress situation.

Background/Aims: Epstein-Barr virus-associated gastric cancers (EBVaGCs) have unique molecular and clinicopathological characteristics. The cyclic GMP-AMP synthase-stimulator of interferon genes (STING) pathway is recently recognized as the critical innate immunity against pathogens and tumors. STING is also a master regulator in the cancer-immunity cycle and targeting STING could synergize with existing immune-checkpoint therapies. However, the role of STING in GC, especially in EBVaGC, and its correlation with programmed death-ligand 1 (PD-L1) remain largely unclear. Methods: We collected 78 cases of EBVaGCs and 210 cases of EBV-negative GC (EBVnGC) from a total of 1,443 cases of GC analyzed by EBV-encoded small RNA in situ hybridization. We investigated STING and PD-L1 expression and their concomitant prognostic value in EBVaGCs and EBVnGCs using tissue microarray and immunohistochemistry. The effects of STING and PD-L1 expression on the overall survival of patients with EBVaGC or EBVnGC were assessed by univariate and multivariate analysis. Results: We found that both STING and PD-L1 exhibited significantly higher expression in the EBVaGCs than that in the EBVnGCs. The expression of STING was positively correlated with that of PD-L1 in EBVaGCs. Simultaneous negative expression of STING and PD-L1, and positive expression of STING were independent prognostic risk factors for EBVaGC and EBVnGC, respectively. Conclusions This is the first prognostic retrospective study of STING and PD-L1 expression and the prognosis among EBVaGC and EBVnGC. The expression and prognostic value of STING and PD-L1 are different in the two types of GCs. STING and PD-L1 are promising prognostic biomarkers and therapeutic targets for EBVaGC and EBVnGC.