Targeting NAD metabolism regulates extracellular adenosine levels to improve the cytotoxicity of CD8+ effector T cells in the tumor microenvironment of gastric cancer.

PURPOSE: Nicotinamide adenine dinucleotide (NAD+) is closely related to the pathogenesis of tumors. However, the effect of NAD+ metabolism of gastric cancer (GC) cells on immune cells remains unexplained. We targeted nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting enzyme in the NAD+ synthesis salvage pathway, to observe its effect in the immune microenvironment. METHODS: NAMPT of GC cell lines was inhibited by using the small molecule inhibitor (FK866) and short hairpin RNA (shRNA). CCK-8 test and flow cytometry were performed to detect cell viability and apoptosis. Immunofluorescence was used to observe changes in mitochondrial membrane potential (MMP).The transfected GC cells (AGS) and patient-derived organoids (PDOs) were cocultured with activated PBMCs, followed by flow cytometric analysis (FCA) for cytokines and inhibitory marker. The level of NAD and ATP of GC cells (AGS & MKN45) was tested combined with NMN and CD39 inhibitor. RESULTS: Targeting NAD+ by FK866 obviously reduced MMP, which ultimately inhibited proliferation and increased the apoptosis of GC cells. NAMPT silencing reduced intracellular NAD and ATP，further decreased extracellular adenosine. Meawhile, the cytokines of CD8+T cells were significantly increased after cocultured with transfected AGS, and the expression of PD-1 was distinctly decreased. NMN reversed the effect of shNAMPT and enhanced the immunosuppression. Consistent results were obtained by coculturing PBMCs with PDOs. CONCLUSION: Restraining the function of NAMPT resulted in the functional improvement of effector CD8+ T cells by decreasing extracellular adenosine levels and inducing apoptosis of GC cells simultaneously. Therefore, this study demonstrates that NAMPT can be an effective target for gastric cancer immunotherapy.

[Construction of Nalm6-Cas9 Cell Line for Genome-Wide Translocation Sequencing].

OBJECTIVE: In order to conduct high-throughput genome-wide translocation sequencing based on CRISPR/Cas9, Nalm6-cas9 monoclonal cell line expressing Cas9 protein was constructed by lentivirus transduction. METHODS: Lentiviral vectors LentiCas9-Blast, pSPAX2, and pMD2.G were used to co-transfect HEK293T cells to obtain recombinant lentivirus. After Nalm6 cells were infected with the recombinant lentivirus, the cells were screened by Blasticidin, and multiple monoclonal cell lines expressing Cas9 protein were obtained by limited dilution. Western blot was used to detect the expression level of Cas9 protein in monoclonal cell lines, and cell count analysis was used to detect the proliferation activity of monoclonal cell lines. LentiCRISPRV2GFP-Δcas9, LentiCRISPRV2GFP-Δcas9-AF4, LentiCRISPRV2GFP-Δ cas9-MLL plasmids were constructed, and transfected with pSPAX2 and pMD2.G, respectively. T vector cloning was used to detect the function of Cas9 protein in Nalm6-Cas9 monoclonal cell line infected with virus. RESULTS: Western blot showed that Nalm6-Cas9_1-6 monoclonal cell line had high expression of Cas9 protein. Cell count analysis showed that high expression of Cas9 protein in Nalm6-Cas9_1-6 monoclonal cell line did not affect cell proliferation activity. The Nalm6-Cas9_1-6 monoclonal cell line had high cleavage activity, and the editing efficiency of AF4 and MLL genes was more than 90% which was determined by T vector cloning. CONCLUSION: Nalm6-Cas9_1-6 monoclonal cell line stably expressing highly active Cas9 protein was obtained, which provided a basis for exploring the translocation of MLL in therapy-related leukemias based on CRISPR/Cas9 genome-wide high-throughput genome-wide translocation sequencing.

[Expression and Significance of BLIMP-1 in Regulatory T Cells of Children with Aplastic Anemia].

OBJECTIVE: To study the expression of B lymphocyte-induced mature protein-1 (BLIMP-1) in regulatory T cells (Tregs) of children with aplastic anemia (AA), and analyze its correlation with the number of Tregs and the levels of inhibitory cytokines interleukin (IL)-10 and transforming growth factor (TGF)-ß in plasma. METHODS: The peripheral blood samples of 10 newly diagnosed AA children and 10 healthy children were collected for experiment. qPCR was used to detect FOXP3 and PRDM1 mRNA expression levels. Flow cytometry was used to detect the proportion of Tregs, the expression of BLIMP-1 in Tregs, and the levels of cytokines such as IL-2, IL-17A, IL-6, interferon (IFN)-γ, IL-10 and TGF-ß in plasma. Pearson correlation model was used to evaluate the relationship between the expression of BLIMP-1 in Treg and the number of Tregs, as well as the levels of IL-10 and TGF-ß in plasma. RESULTS: Compared with control group, the proportion of Tregs in peripheral blood of AA children was decreased significantly (P<0.001); The plasma levels of proinflammatory cytokines IL-2, IL-6 and IFN-γ in AA children were increased significantly (P=0.033, P=0.031, P=0.006), and IL-17A also was increased but the difference was not statistically significant (P=0.052), while anti-inflammatory cytokines IL-10 and TGF-ß were significantly reduced (P=0.048, P=0.002). The relative expressions level of FOXP3 and PRDM1 mRNA in AA children were significantly lower than those in control group (P=0.037, P=0.016). The expression of BLIMP-1 protein in Tregs of AA children was significantly lower than that in control group (P<0.001). The expression level of BLIMP-1 protein in Tregs was positively correlated with the percentage of Tregs in lymphocytes (r=0.671, P=0.001), and was also positively correlated with the levels of IL-10 and TGF-ß in plasma (r=0.500, P=0.029; r=0.486, P=0.030). CONCLUSION: The expression of BLIMP-1 in Tregs of AA children is impaired, and the low expression of BLIMP-1 is related to the decrease of the number in Tregs and IL-10 and TGF-ß expressions.

Mechanical Insights into Thiol-Mediated Synergetic Biotransformation of Cadmium and Selenium in Nematodes.

Cadmium ion (Cd2+) is a common environmental pollutant with high biotoxicity. Interestingly, the Cd2+ biotoxicity can be alleviated by the coexisting selenite (SeO32-), which induces the formation of cadmium selenide-rich nanoparticles (CdSe NPs) under the function of thiol-capping peptides. However, the detailed biochemical mechanisms by which Cd and Se are synergistically transformed into CdSe NPs in living organisms remain unclear so far. Here, we shed light on the molecular basis of such biotransformation processes in Caenorhabditis elegans by focusing on the roles of several key thiol-capping peptides. By monitoring the compositional and structural changes of the Cd and Se species and the genetic-level responses of nematodes, we revealed the specific roles of glutathione (GSH) and phytochelatins (PCs) in mediating the CdSe NP formation. With the aid of in vitro bioassembly assay and density functional theory calculations, the detailed Cd-Se interaction pathways were further deciphered: the ingested Cd binds predominantly to GSH and PCs in sequence, then further interacts with selenocysteine to form tetrahedral-structured PC2-Cd2-Sec2 complex, and ultimately grows into CdSe NPs. This work provides molecular-level insights into the Cd-Se interaction in C. elegans and lays a basis for controlling the ecological and health risks of heavy metals in polluted environment.

Cyclin-dependent kinase 7 inhibitor THZ1 in cancer therapy.

Current cancer therapies have encountered adverse response due to poor therapeutic efficiency, severe side effects and acquired resistance to multiple drugs. Thus, there are urgent needs for finding new cancer-targeted pharmacological strategies. In this review, we summarized the current understanding with THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7), which demonstrated promising anti-tumor activity against different cancer types. By introducing the anti-tumor behaviors and the potential targets for different cancers, this review aims to provide more effective approaches to CDK7 inhibitor-based therapeutic agents and deeper insight into the diverse tumor proliferation mechanisms.

The role of Fusobacterium nucleatum in colorectal cancer: from carcinogenesis to clinical management.

Colorectal cancer (CRC) is a common malignant tumor that affects people worldwide. Metagenomic analyses have shown an enrichment of Fusobacterium nucleatum (F. nucleatum) in colorectal carcinoma tissue; many studies have indicated that F. nucleatum is closely related to the colorectal carcinogenesis. In this review, we provide the latest information to reveal the related molecular mechanisms. The known virulence factors of F. nucleatum promote adhesion to intestinal epithelial cells via FadA and Fap2. Besides, Fap2 also binds to immune cells causing immunosuppression. Furthermore, F. nucleatum recruits tumor-infiltrating immune cells, thus yielding a pro-inflammatory microenvironment, which promotes colorectal neoplasia progression. F. nucleatum was also found to potentiate CRC development through toll-like receptor 2 (TLR2)/toll-like receptor 4 (TLR4) signaling and microRNA (miRNA)-21 expression. In addition, F. nucleatum increases CRC recurrence along with chemoresistance by mediating a molecular network of miRNA-18a*, miRNA-4802, and autophagy components. Moreover, viable F. nucleatum was detected in mouse xenografts of human primary colorectal adenocarcinomas through successive passages. These findings indicated that an increased number of F. nucleatum in the tissues is a biomarker for the diagnosis and prognosis of CRC, and the underlying molecular mechanism can probably provide a potential intervention treatment strategy for patients with F. nucleatum-associated CRC.

[Postoperative complications of acromioclavicular joint dislocation of Tossy III].

OBJECTIVE: To analyze retrospectively the postoperative complications of acromioclavicular joint dislocation (Tossy III) and explore the preventative methods for the complications. METHODS: Forty-eight cases of acromioclavicular joint dislocation (Tossy III) were reviewed, 14 cases treated with open reduction and Kirschner wire combined with steel wire fixation (group A), 11 cases treated with open reduction and lag screw or steel wires fixation (group B), 23 cases treated with open reduction and AO clavicular hook plate fixation (group C). The acromioclavicular ligament, articular capsule, coracoclavicular ligament and coracoacromial ligament were repaired in all patients. The reasons of postoperative complications were analyzed. RESULTS: Forty-eight patients got average follow-up of 18 months. In group A, 8 patients obtained excellent results, 4 good and 2 poor; in group B, 7, 3 and 1, respectively; in group C, 21, 1 and 1, respectively. The excellence rate showed statistical difference between group A and C (P < 0.05). In group A, 4 cases with postoperative pain, 3 cases with periarthritis of shoulder, 3 cases with arthritides of acromioclavicular joint, 4 cases with internal fixation failure and 2 cases with recurrence of joint dislocation; in group B, 3, 2, 1, 3 and 1, respectively; in group C, 22, 2, 1, 2 and 1, respectively. There was no significant difference in postoperative complications in three groups (P > 0.05). CONCLUSION: Selection of the suitable internal fixation and reconstruction of coracoclavicular and coracoacromia ligaments is the basic operation. Acromioclavicular space debridement, ligamentous reconstruction, rigid internal fixation are effective methods to reduce postoperative complications for the treatment of acromioclavicular joint dislocation.