Xiaojun Xu’s research while affiliated with Sun Yat-sen University and other places

Introduction Natural killer (NK) cells, which exert spontaneous cytotoxicity against infectious diseases and cancer, also play an important role in leukemia therapy. Despite the success of NK-based therapy in the treatment of myeloid leukemia, the potential use of NK alloreactivity in these hematologic malignancies remains elusive. The aim of the present study was to investigate whether allogeneic NK cells combined with aclacinomycin (ACM) could enhance anti-leukemic functionality against an acute myeloid leukemia (AML) cell line and to clarify the underlying mechanism. Methods KG-1α and HL-60 AML cell lines were subjected to different treatments. The effects of different drug combinations on cytotoxicity, cell viability, and apoptotic status were examined. Results The results showed that the combination of ACM (40 nmol/l) and allogeneic NK cells (ratio 20:1) was significantly cytotoxic to AML cells and increased the apoptosis of AML cells, especially after 72 h of treatment. Subsequent analyses revealed that the expression of immunogenic cell death (ICD)-related molecules calreticulin, adenosine triphosphate, and high mobility group box 1, as well as NK cell effector production—perforin and granzyme B—was markedly increased in the combination treatment group. These findings suggest that ACM enhances the anti-leukemic activity of allogeneic NK cells through the ICD pathway. Discussion These results demonstrated that allogeneic NK cells had enhanced functional responses when stimulated with ACM in vitro, exhibiting superior effector cytokine production and cytotoxicity compared to the control, which contained conventional NK cells. In conclusion, the present study suggested that the combination of ACM and allogeneic NK cells is a promising therapeutic strategy against AML.

Tripartite motif-containing protein 31 (Trim31) is known to be involved in various pathological conditions, including heart diseases. Nonetheless, its specific involvement in heart failure (HF) has yet to be determined. In this study, we examined the function and mechanism of Trim31 in HF by using mice with cardiac-specific knockout (cKO) of Trim31. The HF mouse model was induced via the subcutaneous injection of isoproterenol (ISO). We observed a decrease in Trim31 expression in the heart tissues of mice with HF. Compared with wild-type (WT) mice, Trim31 cKO mice presented more severe characteristics of HF, including worsened cardiac dysfunction, hypertrophy, and fibrosis. However, these symptoms in Trim31 cKO mice were significantly reversed when they received an intramyocardial injection of recombinant adeno-associated virus (AAV) expressing Trim31. Excessive activation of the NLRP3 inflammasome, manifested by increased levels of NLRP3, ASC, cleaved Caspase-1, cleaved GSDMD, IL-1β, and IL-18, was observed in Trim31 cKO mice with HF. However, Trim31 overexpression effectively reversed the NLRP3 inflammasome activation in Trim31 cKO mice with HF. Selective inhibition of the NLRP3 inflammasome with the NLRP3 inhibitor MCC950 effectively reversed the worsened cardiac dysfunction, hypertrophy, and fibrosis observed in Trim31 cKO mice with HF. Overall, the findings from this study reveal a crucial role of Trim31 in HF. Trim31 deficiency may contribute to the progression of HF by promoting cardiac hypertrophy, fibrosis, and inflammation by facilitating the activation of the NLRP3 inflammasome. Therefore, Trim31 may hold significant potential as a therapeutic target for the treatment of HF.

Relapse is the major cause of treatment failure in Philadelphia chromosome‐positive (Ph⁺) acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (allo‐HSCT). This study aimed to evaluate the effect of a prophylactic tyrosine kinase inhibitor (TKI) strategy on relapse in this population. Patients were assigned to prophylactic or control groups based on measurable residual disease (MRD) pre‐transplantation. The primary endpoint was the cumulative incidence of relapse. A total of 110 patients with Ph⁺ ALL undergoing allo‐HSCT were enrolled in this prospective study. Thirty‐eight patients with positive MRD pre‐transplantation were included in the prophylactic group, and 72 with negative MRD pre‐transplantation were included in the control group. The 4‐year cumulative incidence of relapse was 25.3% (95% CI: 12.1%–41.0%) and 20.3% (11.6%–30.7%; HR = 1.272, 95% CI: 0.551–2.940, p = .549), and non‐relapse mortality was 10.5% (3.3%–22.7%) and 9.7% (4.2%–17.9%; HR = 1.094, 95% CI: 0.320–3.738, p = .928) in the prophylactic and control groups. The 4‐year overall survival was 71.8% (53.2%–84.1%) and 84.1% (72.9%–90.9%; HR = 1.746, 95% CI: 0.741–4.112, p = .196), and leukemia‐free survival was 64.1% (45.8%–77.7%) and 70.0% (57.6%–79.4%; HR = 1.212, 95% CI: 0.607–2.421, p = .585) in the prophylactic and control groups. Our results suggest that prophylactic TKI post‐HSCT in patients with positive MRD pre‐transplantation can produce outcomes comparable to negative MRD pre‐transplantation without TKI post‐HSCT.

Epstein-Barr virus (EBV) related post-transplant lymphoproliferative disorder (EBV-PTLD) is a life-threatening complication after hematopoietic stem cell transplantation (HSCT) or solid organ transplantation (SOT), for which no standard therapeutic means have been developed. Significant increase expression of natural killer group 2 member D ligands (NKG2DLs) was observed on B-lymphoblastoid cells of EBV-PTLD, indicating NKG2DLs as potential therapeutic targets for treatment of EBV-PTLD. In this study, the recombinant constructs of NKG2D CAR and IL-15/IL-15Rα-NKG2D CAR were generated with a retroviral vector and then transduced to human T cells to produce NKG2D CAR-T and IL-15/IL-15Rα-NKG2D CAR-T cells, respectively. B-lymphoblastoid cell lines (B-LCLs) and the xenografted mouse models were established to evaluate the efficacy of these CAR-T cells. IL-15/IL-15Rα-NKG2D CAR-T cells exhibited superior proliferation and antigen-specific cytotoxic effect compared to NKG2D CAR-T, as IL-15/IL-15Rα signaling promoted the expansion of less differentiated central memory T cells (TCM) and increased expression of CD107a and IFN-γ. Moreover, EBV DNA load was dramatically reduced, and 80% B-LCL cells were eliminated by IL-15/IL-15Rα-NKG2D CAR-T cells after co-culturing. In-vivo study confirmed that IL-15/IL-15Rα-NKG2D CAR-T cell therapy significantly enhanced antiviral efficacy in mice, as the serum load of EBV after IL-15/IL-15Rα-NKG2D CAR-T cell infusion was 1500 times lower than the untreated control (P < 0.001). The enhanced efficacy of IL-15/IL-15Rα-NKG2D CAR T cells was probably due to the IL-15/IL-15Rα signaling improved homing and persistence of NKG2D CAR-T cells in vivo, and increased the production of IFN-γ, Perforin, and Granulysin. In conclusion, NKG2D CAR-T cells co-expressing IL-15/IL-15Rα promoted the central memory CAR T cell proliferation and improved the homing and persistence of CAR T cells in vivo, resulting in enhanced anti-tumor and anti-viral effects in treating EBV-PTLD. Supplementary Information The online version contains supplementary material available at 10.1186/s40164-024-00553-z.

Azacitidine is a DNA methyltransferase inhibitor that has been used as a singular agent for the treatment of myelodysplastic syndrome-refractory anemia with excess blast-1 and -2 (MDS-RAEB I/II). However, recurrence and overall response rates following this treatment remain unsatisfactory. The combination of azacitidine and venetoclax has been used for the clinical treatment of a variety of hematological diseases due to the synergistic killing effect of the two drugs. Venetoclax is a BCL-2 inhibitor that can inhibit mitochondrial metabolism. In addition, azacitidine has been shown to reduce the levels of myeloid cell leukemia 1 (MCL-1) in acute myeloid leukemia cells. MCL-1 is an anti-apoptotic protein and a potential source of resistance to venetoclax. However, the mechanism underlying the effects of combined venetoclax and azacitidine treatment remains to be fully elucidated. In the present study, the molecular mechanism underlying the impact of venetoclax on the efficacy of azacitidine was investigated by examining its effects on cell cycle progression. SKM-1 cell lines were treated in vitro with 0-2 µM venetoclax and 0-4 µM azacytidine. After 24, 48 and 72 h of treatment, the impact of the drugs on the cell cycle was assessed by flow cytometry. Following drug treatment, changes in cellular glutamine metabolism pathways was analyzed using western blotting (ATF4, CHOP, ASCT2, IDH2 and RB), quantitative PCR (ASCT2 and IDH2), liquid chromatography-mass spectrometry (α-KG, succinate and glutathione) and ELISA (glutamine and glutaminase). Venetoclax was found to inhibit mitochondrial activity though the alanine-serine-cysteine transporter 2 (ASCT2) pathway, which decreased glutamine uptake. Furthermore, venetoclax partially antagonized the action of azacitidine through this ASCT2 pathway, which was reversed by glutathione (GSH) treatment. These results suggest that GSH treatment can potentiate the synergistic therapeutic effects of venetoclax and azacitidine combined treatment on a myelodysplastic syndrome-refractory anemia cell line at lower concentrations.