Compromised activity of natural killer cells in diffuse large b-cell lymphoma is related to lymphoma-induced modification of their surface receptor expression

NK cells-derived extracellular vesicles potency in the B cell lymphoma biotherapy

Introduction

Extracellular vesicles of Natural Killer cells (NKEV) exert an antitumor effect towards hematopoietic and solid tumors and have an immune modulating effect, suggesting a promising role in immune and biotherapy. In this study, a continuation of our former works, we demonstrated a network by mass spectrometry analysis between NKEV protein cargo and antitumor effects. Human healthy NKEV, both exosomes and microvesicles, have a significant and direct cytotoxic effect against human B cell lymphoma in in vitro and in vivo conditions.

Methods

We isolated extracellular vesicles from in vitro amplified healthy human NK cells and their treatment efficacy was monitored by cytometry analyses, in vivo MRI/MRS measurements, ex vivo MRS analyses and immunohistochemistry.

Results

We observed a remarkable NKEV cytotoxic effect, mainly by apoptosis, on B cell lymphoma in vitro when exosomes and microvesicles were administered simultaneously. In vivo results showed metabolic alterations in SCID mice xenografts after NKEV treatment, associated with a significant reduction of tumor growth (64%). In the in vivo 1H MR spectra we found a significant increase in the tumor lipid/lactate and in taurine signals, both considered as apotosis markers. Ex vivo lymphoma metabolomics revealed a significant increase in fatty acid (FA) pool and decrease in unsaturated and mono-unsaturated FA in treated groups, as compared to control one, thus suggesting an alteration of tumor homeostasis. Immunohistochemistry analyses confirmed the reduction of B-cell lymphoma proliferation rate, as well as the induction of apoptosis following the NKEV treatment.

Conclusions

This study underscore the importance of NKEV as a novel biological acellular tool for B-cell lymphoma treatment, probably having a greater effect on combined treatment regimens. These nanovesicles have an extraordinary potential in innovative cancer immunotherapy, representing a safe and efficient tool naturally circulating in healthy individuals and ready to maintain the immune homeostasis, and therefore a good organism healthy state.

Romanowsky staining: history, recent advances and future prospects from a chemistry perspective

Romanowsky staining was an important methodological breakthrough in diagnostic hematology and cytopathology during the late 19th and early 20th centuries; it has facilitated for decades the work of biologists, hematologists and pathologists working with blood cells. Despite more than a century of studying Romanowsky staining, no systematic review has been published that explains the chemical processes that produce the "Romanowsky effect" or "Romanowsky-Giemsa effect" (RGE), i.e., a purple coloration arising from the interaction of an azure dye with eosin and not due merely to their simultaneous presence. Our review is an attempt to build a bridge between chemists and biomedical scientists and to summarize the available data on methylene blue (MB) demethylation as well as the related reduction and decomposition of MB to simpler compounds by both light and enzyme systems and microorganisms. To do this, we analyze modern data on the mechanisms of MB demethylation both in the presence of acids and bases and by disproportionation due to the action of light. We also offer an explanation for why the RGE occurs only when azure B, or to a lesser extent, azure A is present by applying experimental and calculated physicochemical parameters including dye-DNA binding constants and electron density distributions in the molecules of these ligands. Finally, we discuss modern techniques for obtaining new varieties of Romanowsky dyes by modifying previously known ones. We hope that our critical literature study will help scientists understand better the chemical and physicochemical processes and mechanisms of cell staining with such dyes.

Diffuse large B-cell lymphoma successfully treated with amplified natural killer therapy alone: A case report

BACKGROUND

The prognosis of patients with advanced diffuse large B-cell lymphoma (DLBCL) is poor, with a 5-year survival rate of approximately 50%. The mainstay of treatment is multidrug combination chemotherapy, which has been associated with serious side effects. Amplified natural killer (ANK) cell therapy amplifies and activates natural killer (NK) cells to attack only malignant tumors. As ANK cells attack programmed death ligand 1 (PD-L1)-positive tumor cells, ANK therapy is considered effective against adult T-cell lymphoma and malignant lymphoma.

CASE SUMMARY

Herein, we report a case of an older patient with advanced DLBCL who was successfully treated with ANK immunotherapy. A 91-year-old female visited our hospital with sudden swelling of the right axillary lymph node in April 2022. The patient was diagnosed with stage II disease, given the absence of splenic involvement or contralateral lymphadenopathy. ANK therapy was administered. Six rounds of lymphocyte sampling were performed on July 28, 2022. To reduce the occurrence of side effects, the six samples were diluted by half to obtain 12 samples. Cultured NK cells were administered twice weekly. The treatment efficacy was evaluated by performing computed tomography and serological tests every 1 or 2 mo. The treatment suppressed lesion growth, and the antitumor effect persisted for several months. The patient experienced mild side effects. PD-L1 immunostaining was positive, indicating that the treatment was highly effective.

CONCLUSION

ANK therapy can be used as a first-line treatment for malignant lymphoma; the PD-L1 positivity rate can predict treatment efficacy.

Disruption of the NKG2A:HLA-E Immune Checkpoint Axis to Enhance NK Cell Activation against Cancer

Ligation of the inhibitory receptor NKG2A by its ligand HLA-E negatively regulates the activation of natural killer (NK) cells, as well as subsets of CD8+ T cells and innate T cell populations. NKG2A has recently become a novel immune checkpoint target for the treatment of cancer and direct antibody mediated blockade of NKG2A function is currently under assessment in two phase 3 clinical trials. In addition to direct targeting, the NKG2A:HLA-E axis can also be disrupted indirectly via multiple different targeted cancer agents that were not previously recognised to possess immunomodulatory properties. Increased understanding of immune cell modulation by targeted cancer therapies will allow for the design of rational and more efficacious drug combination strategies to improve cancer patient outcomes. In this review, we summarise and discuss the various strategies currently in development which either directly or indirectly disrupt the NKG2A:HLA-E interaction to enhance NK cell activation against cancer.