Improved anti-solid tumor response by humanized anti-podoplanin chimeric antigen receptor transduced human cytotoxic T cells in an animal model.

Recently, research has been conducted with chimeric antigen receptor (CAR)-T cells to improve efficacy against solid tumors. Humanized CAR improved the long-term survival of CAR-T cells in patients' peripheral blood, resulting in increased therapeutic efficacy. Therefore, the humanization of the CAR-gene sequence is considered an effective method. Podoplanin (PDPN) is a glycosylated transmembrane protein that is highly expressed in solid tumors and is associated with poor prognosis in patients with cancer. Therefore, PDPN is considered a biomarker and good target for cancer treatment with CAR-T cells. Previously, an anti-PDPN CAR was generated from a conventional nonhumanized antibody-NZ-1, the only anti-PDPN antibody for which a CAR was produced. In this study, we investigated other anti-PDPN CARs from the antibody NZ-27, or humanized NZ-1, to enhance the therapeutic potential of CAR-T cells. The CAR signal intensity was enhanced by the efficient expression of CAR proteins on the T-cell surface of NZ-27 CAR-T cells, which show tumor-specific cytotoxicity, proinflammatory cytokine production, and anti-tumor activity against PDPN-expressing tumor xenografts in mice that were significantly better than those in nonhumanized NZ-1 CAR-T cells.

Generation of hypoimmunogenic T cells from genetically engineered allogeneic human induced pluripotent stem cells.

Avoiding the immune rejection of transplanted T cells is central to the success of allogeneic cancer immunotherapies. One solution to protecting T-cell grafts from immune rejection involves the deletion of allogeneic factors and of factors that activate cytotoxic immune cells. Here we report the generation of hypoimmunogenic cancer-antigen-specific T cells derived from induced pluripotent stem cells (iPSCs) lacking ß2-microglobulin, the class-II major histocompatibility complex (MHC) transactivator and the natural killer (NK) cell-ligand poliovirus receptor CD155, and expressing single-chain MHC class-I antigen E. In mouse models of CD20-expressing leukaemia or lymphoma, differentiated T cells expressing a CD20 chimeric antigen receptor largely escaped recognition by NKG2A+ and DNAM-1+ NK cells and by CD8 and CD4 T cells in the allogeneic recipients while maintaining anti-tumour potency. Hypoimmunogenic iPSC-derived T cells may contribute to the creation of off-the-shelf T cell immunotherapies.

Podoplanin as an Attractive Target of CAR T Cell Therapy.

To date, various kinds of cancer immunotherapy methods have been developed, but T cell immunotherapy is one of the most promising strategies. In general, T cell receptor (TCR) or chimeric antigen receptor (CAR) is used to modify the antigen specificity of T cells. CARs possess an underlying potential with treatment efficacy to treat a broad range of cancer patients compared with TCRs. Although a variety of CAR molecules have been developed so far, the clinical application for solid tumors is limited partly due to its adverse effect known as "on-target off-tumor toxicity". Therefore, it is very important for CAR T cell therapy to target specific antigens exclusively expressed by malignant cells. Here, we review the application of T cell immunotherapy using specific antigen receptor molecules and discuss the possibility of the clinical application of podoplanin-targeted CAR derived from a cancer-specific monoclonal antibody (CasMab).

Loss of Dok-1 and Dok-2 in mice causes severe experimental colitis accompanied by reduced expression of IL-17A and IL-22.

Appropriate immune responses and mucosal barrier functions are required for the maintenance of intestinal homeostasis. Defects in this defense system may lead to inflammatory disorders such as inflammatory bowel disease. Downstream of tyrosine kinases 1 (Dok-1) and its closest homolog, Dok-2, are preferentially expressed in immune cells, and play essential roles in the negative regulation of multiple signaling pathways in both innate and adaptive immunity. However, the function of these proteins in intestinal homeostasis remained unclear. Here we show that Dok-1/-2 double knockout (DKO) mice were highly susceptible to dextran sodium sulfate (DSS)-induced colitis compared with Dok-1 or Dok-2 single KO and wild type (WT) mice. Furthermore, DSS-treated Dok-1/-2 DKO mice exhibited increased colonic tissue damage accompanied by reduced proliferation of the epithelial cells relative to WT controls, suggesting that Dok-1/-2 DKO mice have defects in the repair of intestinal epithelial lesions. In addition, the levels of the Th17 cytokines IL-17A and IL-22, which have protective roles in DSS-induced colitis, were reduced in DSS-treated Dok-1/-2 DKO mice compared with WT mice. Taken together, our results demonstrate that Dok-1 and Dok-2 negatively regulate intestinal inflammation, apparently through the induction of IL-17A and IL-22 expression.

Interaction of nectin-like molecule 2 with integrin alpha6beta4 and inhibition of disassembly of integrin alpha6beta4 from hemidesmosomes.

In normal epithelial cells, integrin α(6)ß(4) is abundantly expressed and forms hemidesmosomes, which is a cellular structure that mediates cell-extracellular matrix binding. In many types of cancer cells, integrin α(6)ß(4) is up-regulated, laminin is cleaved, and hemidesmosomes are disrupted, eventually causing an enhancement of cancer cell movement and facilitation of their invasion. We previously showed that the immunoglobulin-like cell adhesion molecule Necl-2 (Nectin-like molecule 2), known as a tumor suppressor, inhibits cancer cell movement by suppressing the ErbB3/ErbB2 signaling. We show here that Necl-2 interacts in cis with integrin α(6)ß(4). The binding of Necl-2 with integrin ß(4) was mediated by its extracellular region. In human colorectal adenocarcinoma Caco-2 cells, integrin α(6)ß(4) was localized at hemidesmosomes. Small interfering RNA-mediated suppression of Necl-2 expression enhanced the phorbol ester-induced disruption of the integrin α(6)ß(4) complex at hemidesmosomes, whereas expression of Necl-2 suppressed the disruption of this structure. These results indicate that tumor-suppressive functions of Necl-2 are mediated by the stabilization of the hemidesmosome structure in addition to the inhibition of the ErbB3/ErbB2 signaling.

Nectins establish a checkerboard-like cellular pattern in the auditory epithelium.

In the auditory epithelium of the cochlea, the sensory hair cells and supporting cells are arranged in a checkerboard-like fashion, but the mechanism underlying this cellular patterning is unclear. We found that mouse hair cells and supporting cells express the immunoglobulin-like adhesion molecules nectin-1 and -3, respectively, and that their interaction mediates the heterotypic adhesion between these two cell types. Genetic removal of nectin-1 or -3 disrupted the checkerboard-like pattern, inducing aberrant attachment between hair cells. When cells expressing either nectin-1 or -3 were cocultured, they arranged themselves into a mosaic pattern. Thus, nectin-1 and -3 promote the formation of the checkerboard-like pattern of the auditory epithelia.

Necl-5/PVR enhances PDGF-induced attraction of growing microtubules to the plasma membrane of the leading edge of moving NIH3T3 cells.

Microtubules (MTs) search for and grow toward the leading edge of moving cells, followed by their stabilization at a specific structure at the rear site of the leading edge. This dynamic re-orientation of MTs is critical to directional cell movement. We previously showed that Necl-5/poliovirus receptor (PVR) interacts with platelet-derived growth factor (PDGF) receptor and integrin α(v) ß(3) at the leading edge of moving NIH3T3 cells, resulting in an enhancement of their directional movement. We studied here the role of Necl-5 in the PDGF-induced attraction of growing MTs to the leading edge of NIH3T3 cells. Necl-5 enhanced the PDGF-induced growth of MTs and attracted them near to the plasma membrane of the leading edge of NIH3T3 cells in an integrin α(v) ß(3) -dependent manner. Furthermore, Necl-5 enhanced the PDGF-induced attraction of the plus-end-tracking proteins (+TIPs), including EB1, CLIP170, an intermediate chain subunit of cytoplasmic dynein, and p150(Glued) , a subunit of dynactin, near to the plasma membrane of the leading edge. Thus, Necl-5 plays a role in the attraction of growing MTs to the plasma membrane of the leading edge of moving cells.