Natural Killer (NK) and CAR-NK Cell Expansion Method using Membrane Bound-IL-21-Modified B Cell Line

Interleukin-21 knockout reduces bone loss in ovariectomized mice by inhibiting osteoclastogenesis

Estrogen deficiency accelerates osteoporosis in elderly women. However, the role of IL-21 in postmenopausal osteoporosis remains unclear. Female wild-type (WT) C57BL/6 and IL-21 knockout (KO) mice were used for ovariectomy (OVX). Here, IL-21 levels were significantly increased in the serum and bone tissues of WT-OVX mice. The trabecular bone space of the femur was significantly increased, and the bone mass was reduced in OVX mice, accompanied by a significant decrease in the maximum load, energy absorption, and elastic modulus indices. In contrast, IL-21 knockout effectively alleviated the effects of OVX on bone mass. Serum TRACP-5b and receptor activator of nuclear factor kappa B ligand (RANKL) levels and osteoclastogenesis were significantly higher in OVX mice than in sham mice, while serum TRACP-5b and RANKL levels and osteoclastogenesis were significantly decreased in IL-21 KO + OVX mice compared to WT + OVX mice. IL-21 knockdown reduces TRACP-5b, RANKL, and osteoclastogenesis, effectively preventing bone resorption and alleviating the progression of OVX-induced osteoporosis.

CAR-NK as a Rapidly Developed and Efficient Immunotherapeutic Strategy against Cancer

Chimeric antigen receptor (CAR)-modified T cell therapy has been rapidly developing in recent years, ultimately revolutionizing immunotherapeutic strategies and providing significant anti-tumor potency, mainly in treating hematological neoplasms. However, graft-versus-host disease (GVHD) and other adverse effects, such as cytokine release syndromes (CRS) and neurotoxicity associated with CAR-T cell infusion, have raised some concerns about the broad application of this therapy. Natural killer (NK) cells have been identified as promising alternative platforms for CAR-based therapies because of their unique features, such as a lack of human leukocyte antigen (HLA)-matching restriction, superior safety, and better anti-tumor activity when compared with CAR-T cells. The lack of CRS, neurotoxicity, or GVHD, in the case of CAR-NK therapy, in addition to the possibility of using allogeneic NK cells as a CAR platform for "off-the-shelf" therapy, opens new windows for strategic opportunities. This review underlines recent design achievements in CAR constructs and summarizes preclinical studies' results regarding CAR-NK therapies' safety and anti-tumor potency. Additionally, new approaches in CAR-NK technology are briefly described, and currently registered clinical trials are listed.