Epigenetic silencing schlafen-11 sensitizes esophageal cancer to ATM inhibitor

BACKGROUND Targeting DNA damage response(DDR)pathway is a cutting-edge strategy.It has been reported that Schlafen-11(SLFN11)contributes to increase chemosensitivity by participating in DDR.However,the detailed mechanism is unclear.AIM To investigate the role of SLFN11 in DDR and the application of synthetic lethal in esophageal cancer with SLFN11 defects.METHODS To reach the purpose,eight esophageal squamous carcinoma cell lines,142 esophageal dysplasia(ED)and 1007 primary esophageal squamous cell carcinoma(ESCC)samples and various techniques were utilized,including methylationspecific polymerase chain reaction,CRISPR/Cas9 technique,Western blot,colony formation assay,and xenograft mouse model.RESULTS Methylation of SLFN11 was exhibited in 9.15%of(13/142)ED and 25.62%of primary(258/1007)ESCC cases,and its expression was regulated by promoter region methylation.SLFN11 methylation was significantly associated with tumor differentiation and tumor size(both P<0.05).However,no significant associations were observed between promoter region methylation and age,gender,smoking,alcohol consumption,TNM stage,or lymph node metastasis.Utilizing DNA damaged model induced by low dose cisplatin,SLFN11 was found to activate non-homologous end-joining and ATR/CHK1 signaling pathways,while inhibiting the ATM/CHK2 signaling pathway.Epigenetic silencing of SLFN11 was found to sensitize the ESCC cells to ATM inhibitor(AZD0156),both in vitro and in vivo.CONCLUSION SLFN11 is frequently methylated in human ESCC.Methylation of SLFN11 is sensitive marker of ATM inhibitor in ESCC.

Epidural electrical stimulation effectively restores locomotion function in rats with complete spinal cord injury

Epidural electrical stimulation can restore limb motor function after spinal cord injury by reactivating the surviving neural circuits.In previous epidural electrical stimulation studies,single electrode sites and continuous tetanic stimulation have often been used.With this stimulation,the body is prone to declines in tolerance and locomotion coordination.In the present study,rat models of complete spinal cord injury were established by vertically cutting the spinal cord at the T8 level to eliminate disturbance from residual nerve fibers,and were then subjected to epidural electrical stimulation.The flexible extradural electrode had good anatomical topology and matched the shape of the spinal canal of the implanted segment.Simultaneously,the electrode stimulation site was able to be accurately applied to the L2–3 and S1 segments of the spinal cord.To evaluate the biocompatibility of the implanted epidural electrical stimulation electrodes,GFAP/Iba-1 doublelabeled immunofluorescence staining was performed on the spinal cord below the electrodes at 7 days after the electrode implantation.Immunofluorescence results revealed no significant differences in the numbers or morphologies of microglia and astrocytes in the spinal cord after electrode implantation,and there was no activated Iba-1~+cell aggregation,indicating that the implant did not cause an inflammatory response in the spinal cord.Rat gait analysis showed that,at 3 days after surgery,gait became coordinated in rats with spinal cord injury under burst stimulation.The regained locomotion could clearly distinguish the support phase and the swing phase and dynamically adjust with the frequency of stimulus distribution.To evaluate the matching degree between the flexible epidural electrode(including three stimulation contacts),vertebral morphology,and the level of the epidural site of the stimulation electrode,micro-CT was used to scan the thoracolumbar vertebrae of rats before and after electrode implantation.Based on the experimental results of gait recovery using three-site stimulation electrodes at L2–3 and S1 combined with burst stimulation in a rat model of spinal cord injury,epidural electrical stimulation is a promising protocol that needs to be further explored.This study was approved by the Animal Ethics Committee of Chinese PLA General Hospital(approval No.2019-X15-39)on April 19,2019.

Long-term clinical observation of patients with acute and chronic complete spinal cord injury after transplantation of Neuro Regen scaffold

Spinal cord injury(SCI)often results in an inhibitory environment at the injury site.In our previous studies,transplantation of a scaffold combined with stem cells was proven to induce neural regeneration in animal models of complete SCI.Based on these preclinical studies,collagen scaffolds loaded with the patients’own bone marrow mononuclear cells or human umbilical cord mesenchymal stem cells were transplanted into SCI patients.Fifteen patients with acute complete SCI and 51 patients with chronic complete SCI were enrolled and followed up for 2 to 5 years.No serious adverse events related to functional scaffold transplantation were observed.Among the patients with acute SCI,five patients achieved expansion of their sensory positions and six patients recovered sensation in the bowel or bladder.Additionally,four patients regained voluntary walking ability accompanied by reconnection of neural signal transduction.Among patients with chronic SCI,16 patients achieved expansion of their sensation level and 30 patients experienced enhanced reflexive defecation sensation or increased skin sweating below the injury site.Nearly half of the patients with chronic cervical SCI developed enhanced finger activity.These long-term follow-up results suggest that functional scaffold transplantation may represent a feasible treatment for patients with complete SCI.