Efficacy of NKG2D CAR-T cells with IL-15/IL-15Rα signaling for treating Epstein-Barr virus-associated lymphoproliferative disorder.

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.

Development of a precision tumor bone metastasis model by a magnetic micro-living-motor system.

An ideal bone metastasis animal model is critical and fundamental for mechanistic research and following development of new drug and treatment. Caudal artery (CA) injection allows bone metastasis in the hindlimb, while in-depth targeted and quantitative studies of bone metastasis require a new model to overcome its limitations. Here, we developed a targeted, quantitative, and highly consistent method for the modeling of bone metastasis with cell-based magnetic micro-living-motor (MLM) system created by effectively combining Fe3O4-PDA-Au with biosafety. The MLM system can achieve efficient migration, target site colonization and control tumorigenesis in bone precisely with the application of a magnetic field. In vivo, day 3 post cell injection, tumor bone metastasis signals were observed locally in the injected femur among 82.76% mice of the MLM group as compared to the 56.82% in the CA group, and the signal intensity was 45.1 and 95.9 times stronger than that in the left and right lower limbs of the CA group, respectively. Post-injection day 28, metastasis in vital organs was reduced by approximately 90% in the MLM group compared to the CA group. Our innovative use of the MLM system in the field of tumor modeling opens a new avenue for exploring the mechanisms of tumor bone metastasis, recurrence and drug resistance.

Cytokines induced memory-like NK cells engineered to express CD19 CAR exhibit enhanced responses against B cell malignancies.

CD19 chimeric antigen receptor (CAR) engineered NK cells have been used for treating patients with relapsed and/or refractory B cell malignancies and show encouraging outcomes and safety profile. However, the poor persistence of NK cells remains a major challenge for CAR NK cell therapy. Memory-like NK cells (MLNK) induced by IL-12, IL-15, and IL-18 have shown enhanced and prolonged responses to tumor re-stimulation, making them an attractive candidate for adoptive cellular immunotherapy. Here, we show efficient and stable gene delivery of CD19 CAR to memory-like NK cells using retroviral vectors with transduction efficiency comparable to those achieved with conventional NK cells. Analysis of surface molecules revealed a distinct phenotypic profile in CAR engineered memory-like NK cells (CAR MLNK), as evidenced by increased expression of CD94 and downregulation of NKp30 as well as KIR2DL1. Compared to conventional CAR NK cells, CAR MLNK cells exhibited significantly increased IFN-γ production and degranulation in response to CD19+ target cells, resulting in enhanced cytotoxic activity against CD19+ leukemia cells and lymphoma cells. Furthermore, memory properties induced by IL-12/-15/-18 improved the in vivo persistence of CAR MLNK cells and significantly suppressed tumor growth in a exnograft mouse model of lymphoma, leading to prolonged survival of CD19+ tumor-bearing mouse. Altogether, our data indicate that CD19 CAR engineered memory-like NK cells exhibited superior persistence and antitumor activity against CD19+ tumors, which might be an attractive approach for treating patient with relapse or refractory B cell malignancies.

Magnetically empowered bone marrow cells as a micro-living motor can improve early hematopoietic reconstitution.

BACKGROUND AIMS: Bone marrow-derived hematopoietic stem cell transplantation/hematopoietic progenitor cell transplantation (HSCT/HPCT) is widely used and one of the most useful treatments in clinical practice. However, the homing rate of hematopoietic stem cells/hematopoietic progenitor cells (HSCs/HPCs) by routine cell transfusion is quite low, influencing hematopoietic reconstitution after HSCT/HPCT. METHODS: The authors developed a micro-living motor (MLM) strategy to increase the number of magnetically empowered bone marrow cells (ME-BMCs) homing to the bone marrow of recipient mice. RESULTS: In the in vitro study, migration and retention of ME-BMCs were greatly improved in comparison with non-magnetized bone marrow cells, and the biological characteristics of ME-BMCs were well maintained. Differentially expressed gene analysis indicated that ME-BMCs might function through gene regulation. In the in vivo study, faster hematopoietic reconstitution was observed in ME-BMC mice, which demonstrated a better survival rate and milder symptoms of acute graft-versus-host disease after transplantation of allogeneic ME-BMCs. CONCLUSIONS: This study demonstrated that ME-BMCs serving as MLMs facilitated the homing of HSCs/HPCs and eventually contributed to earlier hematopoietic reconstitution in recipients. These data might provide useful information for other kinds of cell therapies.

[Detection Rate of Central Nervous System Leukemia Can Be Improved by Cell Preservation Solution].

OBJECTIVE: To investigate whether cell preservation solution can prolong the survival time of leukemia cells and increase the survival rate, so as to improve the detection rate of central nervous system leukemia. METHODS: Kasumi cells were added into cerebrospinal fluid (CSF) supernatant with or without cell preservation solution to compare cell viability and biological characteristics at different time point. Wright Giemsa staining was used to compare cell morphology; cell counting, CCK-8 method, and trypan blue staining were used to compare the cell number, and flow cytometry was used to compare the cell viability. The expression of AML-ETO tumor fusion gene was detected by fluorescence quantitative RT-PCR. RESULTS: At different time points (8 h and 24 h), the survival, molecular biological characteristics and RT-PCR result of the cells in CSF with cell preservation solution were significantly better than those in normal cerebrospinal fluid. CONCLUSION: Cell preservation solution can effectively improve the survival time and survival rate of leukemic cells, thereby increase the detection rate of CNS leukemia.