Combination therapy of DKK1 inhibition and NKG2D chimeric antigen receptor T cells for the treatment of gastric cancer.

Despite the successful application of chimeric antigen receptor (CAR)-T cell therapy in hematological malignancies, the treatment efficacy in solid tumors remains unsatisfactory, largely due to the highly immunosuppressive tumor microenvironment and low density of specific tumor antigens. Natural killer group 2 member D (NKG2D) CAR-T cells have shown promising treatment effects on several cancers such as lymphoma and multiple myeloma. However, the application and efficacy of NKG2D-CAR-T cells in gastric cancer (GC) still needs further exploration. This study identified a novel combination immunotherapy strategy with Dickkopf-1 (DKK1) inhibition and NKG2D-CAR-T cells, exerting synergistic and superior antitumor effect in GC. We show that the baseline expression of NKG2D ligands (NKG2DLs) is at low levels in GC tissues from The Cancer Genome Atlas and multiple GC cell lines including NCI-N87, MGC803, HGC27, MKN45, SGC7901, NUGC4, and AGS. In addition, DKK1 inhibition by WAY-262611 reverses the suppressive tumor immune microenvironment (TIME) and upregulates NKG2DL expression levels in both GC cell lines and GC tissues from a xenograft NCG mouse model. DKK1 inhibition in GC cells markedly improves the immune-activating and tumor-killing ability of NKG2D-CAR-T cells as shown by cytotoxicity assays in vitro. Moreover, the combination therapy of NKG2D-CAR-T and WAY-262611 triggers superior antitumor effects in vivo in a xenograft NCG mouse model. In sum, our study reveals the role of DKK1 in remodeling GC TIME and regulating the expression levels of NKG2DLs in GC. We also provide a promising treatment strategy of combining DKK1 inhibition with NKG2D-CAR-T cell therapy, which could bring new breakthroughs for GC immunotherapy.

Eradication of Hepatocellular Carcinoma by NKG2D-Based CAR-T Cells.

Despite the great success of chimeric antigen receptor T (CAR-T)-cell therapy in the treatment of hematologic malignancies, CAR-T-cell therapy is limited in solid tumors, including hepatocellular carcinoma (HCC). NK group 2 member D (NKG2D) ligands (NKG2DL) are generally absent on the surface of normal cells but are overexpressed on malignant cells, offering good targets for CAR-T therapy. Indeed, analysis of The Cancer Genome Atlas and HCC tumor samples showed that the expression of most NKG2DLs was elevated in tumors compared with normal tissues. Thus, we designed a novel NKG2D-based CAR comprising the extracellular domain of human NKG2D, 4-1BB, and CD3ζ signaling domains (BBz). NKG2D-BBz CAR-T cells efficiently killed the HCC cell lines SMMC-7721 and MHCC97H in vitro, which express high levels of NKG2DLs, whereas they less efficiently killed NKG2DL-silenced SMMC-7721 cells or NKG2DL-negative Hep3B cells. Overexpression of MICA or ULBP2 in Hep3B improved the killing capacity of NKG2D-BBz CAR-T cells. T cells expressing the NKG2D-BBz CAR effectively eradicated SMMC-7721 HCC xenografts. Collectively, these results suggested that NKG2D-BBz CAR-T cells could potently eliminate NKG2DL-high HCC cells both in vitro and in vivo, thereby providing a promising therapeutic intervention for patients with NKG2DL-positive HCC.

T cells expressing NKG2D chimeric antigen receptors efficiently eliminate glioblastoma and cancer stem cells.

BACKGROUND: Traditional therapies fail to cure most glioblastoma patients and the 5-year survival rate is less than 10%, highlighting need for new therapeutic approaches. The natural killer group 2 member D ligands (NKG2DLs) are highly expressed in glioblastomas and are considered promising targets for chimeric antigen receptor (CAR) T-cell therapy. The aim of this study was to investigate the effect of NKG2D-expressing CAR-T cells on glioblastomas and glioblastoma stem cells. METHODS: The expression of NKG2DLs was analyzed by flow cytometry and immunohistochemistry. NKG2D-BBz CAR, containing the extracellular domain of NKG2D, was constructed and delivered into T cells by lentiviral particles. In vitro cytotoxicity of the CAR-T cells was assessed by flow cytometry. Release of cytokine, perforin and granzyme B was quantified using enzyme-linked immunosorbent assay kits. The therapeutic efficacy of NKG2D-BBz CAR-T cells in vivo was evaluated using subcutaneous tumor models. The safety of the CAR was analyzed by investigating the effects on proliferation, apoptosis, and karyotype. RESULTS: Our data confirmed the high expression of NKG2DLs in human glioblastoma cells, cancer stem cells, and tumor samples. Further, the NKG2D-BBz CAR-T cells efficiently lysed glioblastoma cells and cancer stem cells in vitro and produced high levels of cytokines, perforin, and granzyme B. The CAR-T cells markedly eliminated xenograft tumors in vivo and did not exhibit significant treatment-related toxicity in the treated mice. The CAR expression also did not exert any obvious effects on cell proliferation, apoptosis, and genomic stability. CONCLUSION: Our findings demonstrated that NKG2D CAR-T cells targeted glioblastoma cells and cancer stem cells in an NKG2D-dependent manner, supporting the use of CAR-T therapy in glioblastoma therapeutic strategies.

Endocrine network essential for reproductive success in Drosophila melanogaster.

Ecdysis-triggering hormone (ETH) was originally discovered and characterized as a molt termination signal in insects through its regulation of the ecdysis sequence. Here we report that ETH persists in adult Drosophila melanogaster, where it functions as an obligatory allatotropin to promote juvenile hormone (JH) production and reproduction. ETH signaling deficits lead to sharply reduced JH levels and consequent reductions of ovary size, egg production, and yolk deposition in mature oocytes. Expression of ETH and ETH receptor genes is in turn dependent on ecdysone (20E). Furthermore, 20E receptor knockdown specifically in Inka cells reduces fecundity. Our findings indicate that the canonical developmental roles of 20E, ETH, and JH during juvenile stages are repurposed to function as an endocrine network essential for reproductive success.

Synthesis, debugging, and effects of synthetic chromosome consolidation: synVI and beyond.

We describe design, rapid assembly, and characterization of synthetic yeast Sc2.0 chromosome VI (synVI). A mitochondrial defect in the synVI strain mapped to synonymous coding changes within PRE4 (YFR050C), encoding an essential proteasome subunit; Sc2.0 coding changes reduced Pre4 protein accumulation by half. Completing Sc2.0 specifies consolidation of 16 synthetic chromosomes into a single strain. We investigated phenotypic, transcriptional, and proteomewide consequences of Sc2.0 chromosome consolidation in poly-synthetic strains. Another "bug" was discovered through proteomic analysis, associated with alteration of the HIS2 transcription start due to transfer RNA deletion and loxPsym site insertion. Despite extensive genetic alterations across 6% of the genome, no major global changes were detected in the poly-synthetic strain "omics" analyses. This work sets the stage for completion of a designer, synthetic eukaryotic genome.

miR-27b*, an oxidative stress-responsive microRNA modulates nuclear factor-kB pathway in RAW 264.7 cells.

Reactive oxygen species (ROS) produced in macrophages is critical for microbial killing, but they also take part in inflammation and antigen presentation functions. MicroRNAs (miRNAs) are endogenous regulators of gene expression, and they can control immune responses. To dissect the complex nature of ROS-mediated effects in macrophages, we sought to characterize miRNAs that are responsive to oxidative stress-induced with hydrogen peroxide (H(2)O(2)) in the mouse macrophage cell line, RAW 264.7. We have identified a set of unique miRNAs that are differentially expressed in response to H(2)O(2). These include miR-27a*, miR-27b*, miR-29b*, miR-24-2*, and miR-21*, all of which were downregulated except for miR-21*. By using luciferase reporter vector containing nuclear factor-kB (NF-kB) response elements, we demonstrate that overexpression of miR-27b* suppresses lipopolysaccharide-induced activation of NF-kB in RAW 264.7 cells. Our data suggest that macrophage functions can be regulated by oxidative stress-responsive miRNAs by modulating the NF-kB pathway.

Knockdown of ecdysis-triggering hormone gene with a binary UAS/GAL4 RNA interference system leads to lethal ecdysis deficiency in silkworm.

Ecdysis-triggering hormone (ETH) is an integration factor in the ecdysis process of most insects, including Bombyx mori (silkworm). To understand the function of the ETH gene in silkworm, we developed an effective approach to knockdown the expression of ETH in vivo based on RNA interference (RNAi) and a binary UAS/GAL4 expression system that has been successfully used in other insect species. Two kinds of transgenic silkworm were established with this method: the effector strain with the ETH RNAi sequence under the control of UAS and the activator strain with the GAL4 coding sequence under the control of Bombyx mori cytoplasmic actin3. By crossing the two strains, double-positive transgenic silkworm was obtained, and their ETH expression was found to be dramatically lower than that of each single positive transgenic parent. Severe ecdysis deficiency proved lethal to the double-positive transgenic silkworm at the stage of pharate second instar larvae, while the single positive transgenic or wild-type silkworm had normal ecdysis. This UAS/GAL4 RNAi approach provides a way to study the function of endogenous silkworm genes at different development stages.

Development of a heat shock inducible and inheritable RNAi system in silkworm.

A heat shock inducible and inheritable RNA interference (RNAi) system was developed in the silkworm (Bombyx mori). RNAi transgenic silkworms were generated by injecting silkworm eggs with a piggyBac transposon plasmid carrying RNAi sequence against target gene driven by the Drosophila heat shock protein 70 (HSP70) promoter and the helper plasmid expressing piggyBac transposase. The transgenic EGFP gene and the endogenous eclosion hormone (EH) gene were chosen respectively as the target genes. In the RNAi transgenic silkworms, heat shock at 42 degrees C significantly and specifically reduced the expression of EGFP or EH gene in silkworms according to the corresponding RNAi targeting sequence but not in silkworms with the irrelevant RNAi sequence demonstrating the efficiency and specificity of the RNAi effect. Heat shock in the pupal stage hampered pupal-adult eclosion and reduced egg fertility in EH RNAi transgenic silkworms but not in the wild type or EGFP RNAi transgenic silkworms. The establishment of this heat inducible and inheritable conditional RNA interference system in silkworms provided an approach for the first time to dissect the functions of target genes in silkworms at different stages.