A novel MICA/B-targeted chimeric antigen receptor augments the cytotoxicity of NK cells against tumor cells.

Chimeric antigen receptor (CAR)-modified immune cells have emerged as a promising approach for cancer treatment, but single-target CAR therapy in solid tumors is limited by immune escape caused by tumor antigen heterogeneity and shedding. Natural killer group 2D (NKG2D) is an activating receptor expressed in human NK cells, and its ligands, such as MICA and MICB (MICA/B), are widely expressed in malignant cells and typically absent from healthy tissue. NKG2D plays an important role in anti-tumor immunity, recognizing tumor cells and initiating an anti-tumor response. Therefore, NKG2D-based CAR is a promising CAR candidate. Nevertheless, the shedding of MICA/B hinders the therapeutic efficacy of NKG2D-CARs. Here, we designed a novel CAR by engineering an anti-MICA/B shedding antibody 1D5 into the CAR construct. The engineered NK cells exhibited significantly enhanced cytotoxicity against various MICA/B-expressing tumor cells and were not inhibited by NKG2D antibody or NKG2D-Fc fusion protein, indicating no interference with NKG2D-MICA/B binding. Therefore, the developed 1D5-CAR could be combined with NKG2D-CAR to further improve the obstacles caused by MICA/B shedding.

[Corilagin-induced apoptosis of oral squamous carcinoma CAL-27 cells in vitro and in vivo and its mechanism].

PURPOSE: To investigate the effect of corilagin on proliferation and apoptosis of human oral squamous cell carcinoma CAL-27 cells, and to explore the molecular mechanism of inducing cell apoptosis. METHODS: In vitro experiments, Cal-27 cells were treated with different concentrations of corilagin, cell-counting kit-8(CCK-8) assay and colony formation assay were performed to evaluate cell proliferation; flow cytometric analysis was used to evaluate cell apoptosis; qRT-PCR and Western blot assays were performed to evaluate the effect of corilagin on the expression levels of Bax, Bcl-2, Caspase-3, Cleaved Caspase-3 in CAL-27 cells. In vivo experiments, tumor-bearing nude mice was constructed with CAL-27 cells to evaluate the antitumor effect of corilagin. GraphPad Prism 8.0 software package was used for statistical analysis of the data. RESULTS: In vitro experiments showed that corilagin in a dose-dependent manner inhibited proliferation, induced apoptosis, up-regulated Bax, caspase-3, cleaved caspase-3 and down-regulated Bcl-2 at the mRNA and protein levels of CAL-27 cells, and the differences were statistically significant(P＜0.05). In vivo experiments showed that compared with the control group, corilagin could significantly reduce the volume of tumor in nude mice(P＜0.05). CONCLUSIONS: Corilagin can significantly inhibit CAL-27 cell growth and promote its apoptosis both in vitro and in vivo, which may be related to the mediation of Bax/Bcl-2/Caspase-3 signaling pathway.

O-carboxymethyl chitosan based pH/hypoxia-responsive micelles relieve hypoxia and induce ROS in tumor microenvironment.

The hypoxia in tumor microenvironment (TME) can upregulate the HIF-1α and PD-L1 expression and cause immunosuppression of tumor. In this study, a carboxymethyl chitosan-based pH/hypoxia-responsive and γ-Fe2O3/isosorbide dinitrate carrying micelle was designed, and it could catalyze endogenous H2O2 to generate oxygen and relieve hypoxia in TME, so as to relieve the overexpression of HIF-1α and PD-L1 in tumor; meanwhile, it could react with H2O2 to release ROS via Fenton reaction and induce cytotoxicity in tumor. Along with these multiple effects, this carboxymethyl chitosan-based micelles could provide a comprehensive strategy for tumor treatment.