BackgroundThe therapeutic application of T cells endowing with chimeric antigen receptors (CARs) is faced with “on-target, off-tumor” toxicity against solid tumors, particularly in the treatment of the pancreatic cancer. To our best knowledge, the pancreatic cancer cell line AsPC-1 often highly expressed some distinct tumor-associated antigens, such as carcino-embryonic antigen (CEA) and mesothelin (MSLN). Therefore, in this research, we have characterized dual-receptor CAR-modified T cells (dCAR-T) that exert effective and safe cytotoxicity against AsPC-1 cells.MethodsBased on the dual signaling pathway of wild T cells, we designed a novel dCAR diagram specific for CEA and MSLN, which achieved comparable activity relative to that of conventional CAR-T cells (CEA-CAR T or MSLN-CAR T). In this dCAR, a tandem construct containing two physically separate structures, CEA-CD3ζ and MSLN-4/1BB signaling domains were effectively controlled with tumor antigens CEA and MSLN, respectively. Finally, the activity of dCAR-T cells has been verified via in vitro and in vivo experiments.ResultsIn the presence of cognate tumor cells (AsPC-1) expressing both CEA and MSLN, dCAR-T cells exerted high anti-tumor activity relative to that of other single-receptor CAR-T cells bearing only one signaling pathway (e.g., Cζ-CAR and MBB-CAR). In a xenograft model, dCAR-T cells significantly inhibited the growth of AsPC-1 cells yet no effect on the growth of non-cognate tumor cells. Furthermore, the released cytokines and T cell persistence in mice were comparable with that of conventional CAR-T cells, obtaining specific and controllable cytotoxicity.ConclusionsA novel type of CAR-T cells, termed dCAR-T, was designed with specific activities, that is, significant cytotoxicity for two antigen-positive tumor cells yet no cytotoxicity for single antigen-positive tumor cells. Dual-targeted CAR-T cells can be precisely localized at the tumor site and can exert high cytotoxicity against tumor cells, alleviating “on-target, off-tumor” toxicity and enabling accurate application of CAR-T cell therapy.Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0646-9) contains supplementary material, which is available to authorized users.

The potential for adoptive cell immunotherapy as a treatment against cancers has been demonstrated by the remarkable response in some patients with hematological malignancies using autologous T cells endowed with chimeric antigen receptors (CARs) specific for CD19. Clinical efficacy of CAR-T cell therapy for the treatment of solid tumors, however, is rare due to physical and biochemical factors. This review focuses on different aspects of multiple mechanisms of immunosuppression in solid tumors. We characterize the current state of CAR-modified T cell therapy and summarize the various strategies to combat the immunosuppressive microenvironment of solid tumors, with the aim of promoting T cell cytotoxicity and enhancing tumor cell eradication.

Background aims Chimeric antigen receptor T cells (CAR‐T cells) have been successfully used in treatments of hematological tumors, however, their anti‐tumor activity in solid tumor treatments was limited. As IL‐12 increases T‐cell immune functions, we designed carcinoembryonic antigen (CEA) specific CAR‐T (CEA‐CAR‐T) cells and, for the first time, used them in combination with recombinant human IL‐12 (rhIL‐12) to treat several types of solid tumors. Methods In vitro anti‐tumor activity of CEA‐CAR‐T cells in combination with rhIL‐12 was confirmed by evaluation of CEA‐CAR‐T cell activation, proliferation, and cytotoxicity after co‐incubation with CEA‐positive or CEA‐negative human tumor cells. In vivo anti‐tumor activity of CEA‐CAR‐T cells in combination with rhIL‐12 was confirmed in a xenograft model in nude mice for treatments of several types of solid tumors. Results In vitro experiments confirmed that rhIL‐12 significantly increased the activation, proliferation, and cytotoxicity of CEA‐CAR‐T cells. Similarly, in vivo experiments found that CEA‐CAR‐T cells in combination with rhIL‐12 had significantly enhanced anti‐tumor activity than CEA‐CAR‐T cells in growth inhibition of newly colonized colorectal cancer cell HT‐29, pancreatic cancer cell AsPC‐1, and gastric cancer cell MGC803. Conclusions These works confirmed that simultaneous use of cytokines, for example, rhIL‐12, can increase the anti‐tumor activity of CAR‐T cells, especially for treatments of several types of solid tumors.

BackgroundChimeric antigen receptors (CARs) presented on T cell surfaces enable redirection of T cell specificity, which has enormous promise in antitumor therapy. However, excessive activity and poor control over such engineered T cells cause significant safety challenges, such as cytokine release syndrome and organ toxicities. To enhance the specificity and controllable activity of CAR-T cells, we report a novel switchable dual-receptor CAR-engineered T (sdCAR-T) cell and a new switch molecule of FITC-HM-3 bifunctional molecule (FHBM) in this study.MethodsWe designed a fusion molecule comprising FITC and HM-3. HM-3, an antitumor peptide including an Arg-Gly-Asp sequence, can specifically target integrin αvβ3 that is presented on some tumor cells. Moreover, to improve the specificity of CAR-T cells, we also generated the sdCAR-T cell line against cognate tumor cells expressing human mesothelin (MSLN) and integrin αvβ3. Finally, the activity of sdCAR-T cell and FHBM is verified via in vitro and in vivo experiments.ResultsIn the presence of FHBM, the designed sdCAR-T cells exerted high activity including activation and proliferation and had specific cytotoxicity in a time- and dose-dependent manner in vitro. Furthermore, using a combination of FHBM in nude mice, sdCAR-T cells significantly inhibited the growth of MSLN+ K562 cells and released lower levels of the cytokines (e.g., interleukin-2, interferon γ, interleukin-6, and tumor necrosis factor α) relative to conventional CAR-T cells, obtaining specific, controllable, and enhanced cytotoxicity.ConclusionsOur data indicate that FHBM can accurately control timing and dose of injected CAR-T cells, and sdCAR-T cells exert significant antitumor activity while releasing lower levels of cytokines for the cognate tumor cells expressing both MSLN and integrin αvβ3. Therefore, combination therapies using sdCAR-T cells and the switch molecule FHBM have significant potential to treat malignancies.Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0591-7) contains supplementary material, which is available to authorized users.

We used a machine learning method, the nearest neighbor algorithm (NNA), to learn the relationship between miRNAs and their target proteins, generating a predictor which can then judge whether a new miRNA-target pair is true or not. We acquired 198 positive (true) miRNA-target pairs from Tarbase and the literature, and generated 4,888 negative (false) pairs through random combination. A 0/1 system and the frequencies of single nucleotides and di-nucleotides were used to encode miRNAs into vectors while various physicochemical parameters were used to encode the targets. The NNA was then applied, learning from these data to produce a predictor. We implemented minimum redundancy maximum relevance (mRMR) and properties forward selection (PFS) to reduce the redundancy of our encoding system, obtaining 91 most efficient properties. Finally, via the Jackknife cross-validation test, we got a positive accuracy of 69.2% and an overall accuracy of 96.0% with all the 253 properties. Besides, we got a positive accuracy of 83.8% and an overall accuracy of 97.2% with the 91 most efficient properties. A web-server for predictions is also made available at http://app3.biosino.org:8080/miRTP/index.jsp.