Research on the effects of CD137 signaling on the function of CD3−CD56+NK cells

Magnetic delivery of Fe3O4@polydopamine nanoparticle-loaded natural killer cells suggest a promising anticancer treatment

Natural killer (NK)-cell-based immunotherapy has been reported to have promising prospects in the treatment of non-small cell lung cancer, one of the most common malignancies in the world. It has been proven that higher the NK cell infiltration into the tumor, the better is the curative effect. Therefore, it would be beneficial to develop a method that increases NK cell recruitment and infiltration into the tumor site. The purpose of this study was to establish an immune-cell delivery system for clear lung cancer cells based on magnetic nanoparticle (NP)-labeled NK cells that can be accumulated at the tumor site by placing a tiny external magnetic device inside animals. We developed superparamagnetic iron oxide NPs consisting of a magnetic Fe3O4 core and a shell of polydopamine (PDA) for magnetic targeting therapy. Fe3O4@PDA NPs possess favorable physiological stability and biocompatibility that facilitate their active uptake by NK cells. The biology of NK cells was not affected by the presence of NPs. In vitro and in vivo studies showed that Fe3O4@PDA NP-labeled NK cells significantly inhibited tumor growth and reduced the expression of Ki-67 and increased the apoptosis of A549 cancer cells. H&E staining showed Fe3O4@PDA NP-labeled NK cells, under a magnetic field, had higher intra-tumoral iron density and increased accumulation of CD56+ NK cells. Our results suggest that Fe3O4@PDA NPs are a promising magnetic nanomaterial that can manipulate immune cells, thereby inhibiting tumor growth.

Recombinant Salmonella-based CEACAM6 and 4-1BBL vaccine enhances T-cell immunity and inhibits the development of colorectal cancer in rats: In vivo effects of vaccine containing 4-1BBL and CEACAM6

The present study aimed to determine the effect of recombinant Salmonella (SL3261)-based CEACAM6 and 4-1BB ligand (4-1BBL) vaccine on the development of colorectal cancer in rats and the potential immune mechanisms involved. Attenuated Salmonella typhimurium (vaccine strain)‑carrying plasmids pIRES-CEACAM6, pIRES‑4‑1BBL and pIRES-CEACAM6-4-1BBL were constructed. The rats were administered subcutaneous injections of 1,2-dimethyl-hydrazine (DMH) once a week for 18 weeks. Eight weeks after the first injection, the rats were divided into the pIRES/SL3261, pIRES-4-1BBL/SL3261, pIRES-CEACAM6/SL3261 and pIRES-CEACAM6-4-1BBL/SL3261 groups, and fed with corresponding vaccine strains. The rats were then sacrificed, the number of colon tumors were recorded, and the Dukes' stage were evaluated. CD3, CD4, CD8, CD56, FOXP3 and CEACAM6 expression in tumor tissues was determined by immunohistochemical staining. Compared with the expression levels in the pIRES/SL3261 group, similar levels of CD3+, CD8+ and CD56+ expression were identified for the pIRES-CEACAM6/SL3261 group of rats. Additionally, a comparable number of tumors was detected in the pIRES-4-1BBL/SL3261 and pIRES-CEACAM6/SL3261 groups. By contrast, a significantly fewer number of tumors, albeit with a higher density of CD3+CD8+, CD56+ and a lower density of Foxp3+ tumor-infiltrating lymphocyte (TIL) cells was detected in the pIRES-CEACAM6-4-1BBL/SL3261 group of rats. The results indicated that vaccination with recombinant attenuated Salmonella harboring the CEACAM6 and 4-1BBL gene efficiently increased the number of CD3+CD8+ TIL and NK cells, decreased the number of FOXP3 cells and inhibited the development of DMH-induced colorectal cancer in rats.