Expansion of NK cells for the treatment of multiple myeloma

The purpose of this study was to test the efficacy of expanded natural killer cells (eNKs) as a treatment against multiple myeloma (MM) cell lines and MM patient bone marrow aspirates. The cytotoxic effect of eNKs was studied alone and in combination with daratumumab, anti-CD38 monoclonal antibody approved for use in multiple myeloma patients. In multiple myeloma cell lines, eNKs were found to have a dramatic cytotoxic effect against the cells. For the patient samples, when eNKs were harvested during the optimum expansion period, they produced a cytotoxic effect against the MM cells. Daratumumab was also effective against some of the patient samples. However, when combined, eNKs and daratumumab produced a greater percent of specific cell death than both separately, on all cells tested. Combination therapy maximizes the effect of each individual treatment. This important finding supports the possible use of combination eNKs with daratumumab therapy against multiple myeloma in further trials

Dynamic Changes in miRNA Expression during the Generation of Expanded and Activated NK Cells

Cytotoxicity; Immunotherapy; miRNACitotoxicidad; Inmunoterapia; miARNCitotoxicitat; Immunoteràpia; miRNATherapies based on allogenic Natural Killer (NK) cells are becoming increasingly relevant, and our laboratory has produced expanded and activated NK (eNK) cells that are highly cytotoxic against several hematological cancers when used alone or in combination with currently approved therapeutic monoclonal antibodies. In order to produce eNK cells, healthy human donor NK cells undergo a 20-day expansion protocol with IL-2, IL-15 and Epstein–Barr virus (EBV)-transformed lymphoblastoid feeder cells. In order to produce an even more potent eNK-based therapy, we must elucidate the changes our protocol produces within healthy NK cells. To understand the post-transcriptional changes responsible for the increased cytolytic abilities of eNK cells, we performed microRNA (miRNA) expression analysis on purified NK cells from day 0 and day 20 of the protocol using quantitative reverse transcription PCR (RT-qPCR). Of the 384 miRNAs profiled, we observed changes in the expression of 64 miRNAs, with especially significant changes in 7 of them. The up-regulated miRNAs of note were miRs-146a, -124, -34a, and -10a, which are key in the regulation of cell survival through the modulation of pro-apoptotic genes such as PUMA. The down-regulation of miRs-199a, -223, and -340 was also detected and is associated with the promotion of NK cell cytotoxicity. We validated our analysis using immunoblot and flow cytometry studies on specific downstream targets of both up- and down-regulated miRNAs such as PUMA and Granzyme B. These results corroborate the functional importance of the described miRNA expression patterns and show the wide variety of changes that occur in eNK cells at day 20.This research was supported by project PID2019-105128RB-I00 financed by MCIN/AEI/10.13039/501100011033/ and “FEDER Una manera de hacer Europa” and by Government of Aragon grant B31_20R

Harnessing the potential of NK cell-based immunotherapies against multiple myeloma

Natural killer (NK) cell-based therapies have emerged as promising anticancer treatments due to their potency as cytolytic effectors and synergy with concurrent treatments. Multiple myeloma (MM) is an aggressive B-cell malignancy that, despite development of novel therapeutic agents, remains incurable with a high rate of relapse. In MM, the inhospitable tumor microenvironment prevents host NK cells from exerting their cytolytic function. The development of NK cell immunotherapy works to overcome this altered immune landscape and can be classified in two major groups based on the origin of the cell: autologous or allogeneic. In this review, we compare the treatments in each group, such as autologous chimeric antigen receptor (CAR) NKs and allogeneic off-the-shelf NK cell infusions, and their combinatorial effect with existing MM therapies including monoclonal antibodies and proteasome inhibitors. We also discuss their placement in clinical treatment regimens based on the immune profile of each patient. Through this examination, we would like to discover precisely when each NK cell-based treatment will produce the maximum benefit to the MM patient

yuDetecting the percent of peripheral blood mononuclear cells displaying p-STAT-3 in malignant glioma patients

<p>Abstract</p> <p>Background</p> <p>The signal transducer and activator of transcription 3 (STAT-3) is frequently overexpressed in cancer cells, propagates tumorigenesis, and is a key regulator of immune suppression in cancer patients. The presence of phosphorylated STAT-3 (p-STAT-3) in the tumor can induce p-STAT-3 in tumor-associated immune cells that can return to the circulatory system. We hypothesized that the number of peripheral blood mononuclear cells (PBMCs) displaying p-STAT-3 would be increased in glioma patients, which would correlate with the extent of tumor-expressed p-STAT-3, and that higher p-STAT-3 levels in peripheral blood would correlate with a higher fraction of immune-suppressive regulatory T cells (Tregs).</p> <p>Methods</p> <p>We measured the percentage of PBMCs displaying p-STAT-3 in 19 healthy donors and 45 patients with primary brain tumors. The level of p-STAT-3 in tumor tissue was determined by immunohistochemistry. The degree of immune suppression was determined based on the fraction of Tregs in the CD4 compartment.</p> <p>Results</p> <p>Healthy donors had 4.8 ± 3.6% of PBMCs that expressed p-STAT-3, while the mean proportion of PBMCs displaying p-STAT-3 in patients with GBM was 11.8 ± 13.5% (<it>P </it>= 0.03). We did not observe a correlation by Spearman correlation between the degree of p-STAT-3 levels in the tumor and the percent of PBMCs displaying p-STAT-3. Furthermore, the percent of PBMCs displaying p-STAT-3 in glioma patients was not directly correlated with the fraction of Tregs in the CD4 compartment.</p> <p>Conclusion</p> <p>We conclude that the percent of PBMCs displaying p-STAT-3 may be increased in malignant glioma patients.</p

Harnessing the Potential of NK Cell-Based Immunotherapies against Multiple Myeloma

International audienceNatural killer (NK) cell-based therapies have emerged as promising anticancer treatments due to their potency as cytolytic effectors and synergy with concurrent treatments. Multiple myeloma (MM) is an aggressive B-cell malignancy that, despite development of novel therapeutic agents, remains incurable with a high rate of relapse. In MM, the inhospitable tumor microenvironment prevents host NK cells from exerting their cytolytic function. The development of NK cell immunotherapy works to overcome this altered immune landscape and can be classified in two major groups based on the origin of the cell: autologous or allogeneic. In this review, we compare the treatments in each group, such as autologous chimeric antigen receptor (CAR) NKs and allogeneic off-the-shelf NK cell infusions, and their combinatorial effect with existing MM therapies including monoclonal antibodies and proteasome inhibitors. We also discuss their placement in clinical treatment regimens based on the immune profile of each patient. Through this examination, we would like to discover precisely when each NK cell-based treatment will produce the maximum benefit to the MM patient

Expanded and activated allogeneic NK cells are cytotoxic against B-chronic lymphocytic leukemia (B-CLL) cells with sporadic cases of resistance

International audienceAdoptive transfer of allogeneic natural killer (NK) cells is becoming a credible immunotherapy for hematological malignancies. In the present work, using an optimized expansion/activation protocol of human NK cells, we generate expanded NK cells (eNK) with increased expression of CD56 and NKp44, while maintaining that of CD16. These eNK cells exerted significant cytotoxicity against cells from 34 B‑CLL patients, with only 1 sample exhibiting resistance. This sporadic resistance did not correlate with match between KIR ligands expressed by the eNK cells and the leukemic cells, while cells with match resulted sensitive to eNK cells. This suggests that KIR mismatch is not relevant when expanded NK cells are used as effectors. In addition, we found two examples of de novo resistance to eNK cell cytotoxicity during the clinical course of the disease. Resistance correlated with KIR‑ligand match in one of the patients, but not in the other, and was associated with a significant increase in PD‑L1 expression in the cells from both patients. Treatment of one of these patients with idelalisib correlated with the loss of PD‑L1 expression and with re‑sensitization to eNK cytotoxicity. We confirmed the idelalisib‑induced decrease in PD‑L1 expression in the B‑CLL cell line Mec1 and in cultured cells from B‑CLL patients. As a main conclusion, our results reinforce the feasibility of using expanded and activated allogeneic NK cells in the treatment of B‑CLL