Metformin promotes anti-tumor immunity in STK11 mutant NSCLC through AXIN1-dependent upregulation of multiple nucleotide metabolites

Background:Metformin has pleiotropic effects beyond glucose reduction,including tumor inhibition and immune regulation.It enhanced the anti-tumor effects of programmed cell death protein 1(PD-1)inhibitors in serine/threonine kinase 11(STK11)mutant non-small cell lung cancer(NSCLC)through an axis inhibition protein 1(AXIN1)-dependent manner.However,the alterations of tumor metabolism and metabolites upon metformin administration remain unclear.Methods:We performed untargeted metabolomics using liquid chromatography(LC)-mass spectrometry(MS)/MS system and conducted cell experiments to verify the results of bioinformatics analysis.Results:According to the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway database,most metabolites were annotated into metabolism,including nucleotide metabolism.Next,the differentially expressed metabolites in H460(refers to H460 cells),H460_met(refers to metformin-treated H460 cells),and H460_KO_met(refers to metformin-treated Axin1-/-H460 cells)were distributed into six clusters based on expression patterns.The clusters with a reversed expression pattern upon metformin treatment were selected for further analysis.We screened out metabolic pathways through KEGG pathway enrichment analysis and found that multiple nucleotide metabolites enriched in this pathway were upregulated.Furthermore,these metabolites enhanced the cytotoxicity of activated T cells on H460 cells in vitro and can activate the stimulator of the interferon genes(STING)pathway independently of AXIN1.Conclusion:Relying on AXIN1,metformin upregulated multiple nucleotide metabolites which promoted STING signaling and the killing of activated T cells in STK11 mutant NSCLC,indicating a potential immunotherapeutic strategy for STK11 mutant NSCLC.

Biomechanical Comparison of Gourd-shaped LCP versus LCP for Fixation of Comminuted Tibial Shaft Fracture

The purpose of this study was to compare monotonic biomechanical properties of gourd-shaped LCP fixation with LCP fixation of human tibial shaft in gap fracture mode. Twenty paired fresh cadaveric human tibias were randomly divided into 4 groups （5 pairs each）： （1） axial loading sin- gle cycle to failure testing, （2） torsion single cycle to failure testing, （3） 4-point bending single cycle to failure testing, and （4） dynamic 4-point bending testing. A 7-hole 4.5 mm gourd-shaped LCP was se- cured on the anteromedial surface of 1 randomly selected bone from each pair, respectively, using 6 locking screws in the 1st, 2nd, 3rd, 5th, 6th and 7th hole with the middle hole unfilled and just located at the mid-diaphysis of the tibia. A 7-hole 4.5 mm LCP was secured on the other bone with the same method. Standard AO/ASIF techniques were used. After fixation finished, a 10 mm gap in the mid-diaphysis of tibia was created, centrally located at the unfilled hole. The axial, torsional, and bending stiffness and failure strengths were calculated from the collected data in static testings and statisti- cally compared using paired Student＇s t-test. The 4-point bending fatigue lives of the two constructs were calculated from the dynamic testing data and also statistically compared using paired Student＇s t-test. Failure modes were recorded and visually analyzed. P〈0.05 was considered significant. Results showed that the axial, torsional and bending stiffness of gourd-shaped LCP construct was greater （4%, 19%, 12%, respectively, P〈0.05） than that of the LCP construct, and the axial, torsional and bending failure strengths of gourd-shaped LCP construct were stronger （10%, 46%, 29%, respectively, P〈0.05） than those of the LCP construct. Both constructs failed as a result of plate plastic torsional deformation. After axial loading and 4-point bending testings, LCP failed in term of an obvious deformation of bent apex just at the unfilled plate hole, while the gourd-shaped LCP failed in term of a deformation of bent arc between the 3rd and 5th holes, which indicated a more consistent stress distribution on gourd-shaped LCP. Fatigue life of gourd-shaped LCP construct was significantly greater than LCP construct （153 836±2 228 vs. 132 471±6 460 cycles, P〈0.01）. All constructs failed as a result of fracture of the plate through the compression hole of the unfilled combination screw hole. The biomechanical testing showed that gourd-shaped LCP can provide greater stiffness and strength, and longer fatigue life than LCP. The gourd-shaped LCP may be more advantageous mechanically and may reduce the plate breakage rate clinically.

Ubiquitination in osteosarcoma:unveiling the impact on cell biology and therapeutic strategies

Ubiquitination,a multifaceted post-translational modification,regulates protein function,degradation,and gene expression.The pivotal role of ubiquitination in the pathogenesis and progression of cancer,including colorectal,breast,and liver cancer,is well-established.Osteosarcoma,an aggressive bone tumor predominantly affecting adolescents,also exhibits dysregulation of the ubiquitination system,encompassing both ubiquitination and deubiquitination processes.This dysregulation is now recognized as a key driver of osteosarcoma development,progression,and chemoresistance.This review highlights recent progress in elucidating how ubiquitination modulates tumor behavior across signaling pathways.We then focus on the mechanisms by which ubiquitination influences osteosarcoma cell function.Finally,we discuss the potential for targeting the ubiquitin-proteasome system in osteosarcoma therapy.By unraveling the impact of ubiquitination on osteosarcoma cell physiology,we aim to facilitate the development of novel strategies for prognosis,staging,treatment,and overcoming chemoresistance.

Sepsis-induced immunosuppression:mechanisms,diagnosis and current treatment options

Sepsis is a common complication of combat injuries and trauma,and is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection.It is also one of the significant causes of death and increased health care costs in modern intensive care units.The use of antibiotics,fluid resuscitation,and organ support therapy have limited prognostic impact in patients with sepsis.Although its pathophysiology remains elusive,immunosuppression is now recognized as one of the major causes of septic death.Sepsis-induced immunosuppression is resulted from disruption of immune homeostasis.It is characterized by the release of antiinflammatory cytokines,abnormal death of immune effector cells,hyperproliferation of immune suppressor cells,and expression of immune checkpoints.By targeting immunosuppression,especially with immune checkpoint inhibitors,preclinical studies have demonstrated the reversal of immunocyte dysfunctions and established host resistance.Here,we comprehensively discuss recent findings on the mechanisms,regulation and biomarkers of sepsis-induced immunosuppression and highlight their implications for developing effective strategies to treat patients with septic shock.

PDGFR kinase inhibitor protects against septic death via regulation of BTLA

Sepsis,defined as life-threatening organ failure caused by a dysregulated host response to severe infection,is a major cause of death among intensive care unit patients.Therapies targeting on immunomodulatory is a new research field in sepsis treatment.B-and T-lymphocyte attenuator(BTLA)is an inhibitory costimulatory factor molecule of B and T lymphocytes.Studies have shown that elevated expression of BTLA in lymphocytes can reduce mortality in sepsis,but its regulatory compounds and the underlying mechanism remains to be elucidated.Here,we show that treatment with CP-673451 significantly decreases mortality of septic mouse.CP-673451 is a PDGFR kinase inhibitor which can promote the expression of BTLA,inhibit the release of chemokines such as CXCL13,and reduce first the chemotaxis of B cells to the peripheral blood and vital organs.CP-673451 also inhibits both the release of cytokines and chemokines such as IL-1β,IL-6,IL-10,TNF-α,CCL1,CCL2 and CCL7 and reduces both the chemotactic ability of T cells.This suggests that CP-673451 may prevent septic death by inhibiting lymphocyte chemotaxis and alleviating“cytokine storm”.In conclusion,our study provides a new therapeutic target and an effective compound for sepsis treatment.

Electrotaxis of alveolar epithelial cells in direct-current electric fields

Purpose:This study aims to elucidate the electrotaxis response of alveolar epithelial cells(AECs)in direct-current electric fields(EFs),explore the impact of EFs on the cell fate of AECs,and lay the foundation for future exploitation of EFs for the treatment of acute lung injury.Methods:AECs were extracted from rat lung tissues using magnetic-activated cell sorting.To elucidate the electrotaxis responses of AECs,different voltages of EFs(0,50,100,and 200 mV/mm)were applied to two types of AECs,respectively.Cell migrations were recorded and trajectories were pooled to better demonstrate cellular activities through graphs.Cell directionality was calculated as the cosine value of the angle formed by the EF vector and cell migration.To further demonstrate the impact of EFs on the pulmonary tissue,the human bronchial epithelial cells transformed with Ad12-SV402B(BEAS-2B cells)were obtained and experimented under the same conditions as AECs.To determine the influence on cell fate,cells underwent electric stimulation were collected to perform Western blot analysis.Results:The successful separation and culturing of AECs were confirmed through immunofluorescence staining.Compared with the control,AECs in EFs demonstrated a significant directionality in a voltage-dependent way.In general,type I alveolar epithelial cells migrated faster than type II alveolar epithelial cells,and under EFs,these two types of cells exhibited different response threshold.For type II alveolar epithelial cells,only EFs at 200 mV/mm resulted a significant difference to the velocity,whereas for,EFs at both 100 mV/mm and 200 mV/mm gave rise to a significant difference.Western blotting suggested that EFs led to an increased expression of a AKT and myeloid leukemia 1 and a decreased expression of Bcl-2-associated X protein and Bcl-2-like protein 11.Conclusion:EFs could guide and accelerate the directional migration of AECs and exert antiapoptotic effects,which indicated that EFs are important biophysical signals in the re-epithelialization of alveolar epithelium in lung injury.

Zn^(2+)-Loaded adhesive bacterial cellulose hydrogel with angiogenic and antibacterial abilities for accelerating wound healing

Background:Wound healing is a process that requires angiogenesis and antibacterial activities and it remains a challenge for both experimental and clinical research worldwide.Zn2+has been reported to be widely involved in angiogenesis and exerts antibacterial effects,making it suitable as a treatment to promote wound healing.Therefore Zn2+-loaded adhesive bacterial cellulose hydrogel was designed to observe its angiogenic and antibacterial abilities in the wound healing process.Methods:The characterization,tensile strength,swelling behaviors and antibacterial activity of bacterial cellulose/polydopamine/zeolitic imidazolate framework-8(BC/PDA/ZIF8)hydrogels were tested.Cell-Counting-Kit-8(CCK8),transwell,tube formation and real time qunantitative PCR(qRT-PCR)assays were performed to evaluate the cell compatibility of BC/PDA/ZIF8 hydrogels in vitro.A full-thickness defect wound model and histological assays were used to evaluate the BC/PDA/ZIF8 hydrogels in vivo.Results:The prepared BC/PDA/ZIF8 hydrogels exhibited suitable mechanical strength,excellent swelling properties,good tissue adhesion,efficient angiogenic and antibacterial effects and good performance as a physical barrier.In vivo experiments showed that the BC/PDA/ZIF8 hydrogels accelerated wound healing in a full-thickness defect wound model by stimulating angiogenesis.Conclusions:This study proved that BC/PDA/ZIF8 hydrogels possess great potential for promoting satisfactory wound healing in full-thickness wound defects through antibacterial effects and improved cell proliferation,tissue formation,remodeling and re-epithelialization.