Teresa Caballero-Velázquez

Immunomodulatory effect of 5-azacytidine (5-azaC): potential role in the transplantation setting

Cytokine genes are targets of multiple epigenetic mechanisms in T lymphocytes. 5-azacytidine (5-azaC) is a nucleoside-based DNA methyltransferase inhibitor that induces demethylation and gene reactivation. In the current study, we analyzed the effect of 5-azaC in T-cell function and observed that 5-azaC inhibits T-cell proliferation and activation, blocking cell cycle in the G(0) to G(1) phase and decreasing the production of proinflammatory cytokines such as tumor necrosis factor-alpha and interferon-gamma. This effect was not attributable to a proapoptotic effect of the drug but to the down-regulation of genes involved in T-cell cycle progression and activation such as CCNG2, MTCP1, CD58, and ADK and up-regulation of genes that induce cell-growth arrest, such as DCUN1D2, U2AF2, GADD45B, or p53. A longer exposure to the drug leads to demethylation of FOXP3 promoter, overexpression of FOXP3, and expansion of regulatory T cells. Finally, the administration of 5-azaC after transplantation prevented the development of graft-versus-host disease, leading to a significant increase in survival in a fully mismatched bone marrow transplantation mouse model. In conclusion, the current study shows the effect of 5-azaC in T lymphocytes and illustrates its role in the allogeneic transplantation setting as an immunomodulatory drug, describing new pathways that must be explored to prevent graft-versus-host disease.

Treatment with bortezomib of human CD4+ T cells preserves natural regulatory T cells and allows the emergence of a distinct suppressor T-cell population

In vitro depletion of alloreactive T cells using the proteasome inhibitor bortezomib is a promising approach to prevent graft-versus-host disease (GVHD) after allogeneic stem cell transplantation. The findings of this study strengthen the idea of using bortezomib in the prevention of GVHD, not only because of its selective cytotoxic effect on activated T cells, but also due to its ability to preserve and/or generate regulatory T cells. Background In vitro depletion of alloreactive T cells using the proteasome inhibitor bortezomib is a promising approach to prevent graft-versus-host disease after allogeneic stem cell transplantation. We have previously described the ability of bortezomib to selectively eliminate alloreactive T cells in a mixed leukocyte culture, preserving non-activated T cells. Due to the role of regulatory T cells in the control of graft versus host disease, in the current manuscript we have analyzed the effect of bortezomib in regulatory T cells. Design and Methods Conventional or regulatory CD4+ T cells were isolated with immunomagnetic microbeads based on the expression of CD4 and CD25. The effect of bortezomib on T-cell viability was analyzed by flow cytometry using 7-amino-actinomycin D staining. To investigate the possibility of obtaining an enriched regulatory T-cell population in vitro with the use of bortezomib, CD4+ T cells were cultured during four weeks in the presence of anti-CD3 and anti-CD28 antibodies, IL-2 and bortezomib. The phenotype of these long-term cultured cells was studied, analyzing the expression of CD25, CD127 and FOXP3 by flow cytometry, and mRNA levels were determined by RT-PCR. Their suppressive capacity was assessed in co-culture experiments, analyzing proliferation and IFN-γ and CD40L expression of stimulated responder T cells by flow cytometry. Results We observed that naturally occurring CD4+CD25+ regulatory T cells are resistant to the pro-apoptotic effect of bortezomib. Furthermore, we found that long-term culture of CD4+ T cells in the presence of bortezomib promotes the emergence of a regulatory T-cell population that significantly inhibits proliferation, IFN-γ production and CD40L expression among stimulated effector T cells. Conclusions These results reinforce the proposal of using bortezomib in the prevention of graft versus host disease and, moreover, in the generation of regulatory T-cell populations, that could be used in the treatment of multiple T-cell mediated diseases.

Phase II clinical trial for the evaluation of bortezomib within the reduced intensity conditioning regimen (RIC) and post‐allogeneic transplantation for high‐risk myeloma patients

The current study was designed to assess the safety and efficacy of bortezomib in combination with fludarabine and melphalan as reduced intensity conditioning before allogeneic stem cell transplantation in patients with high risk multiple myeloma. Sixteen patients were evaluable. The median number of previous line of treatment was 3; all patients had relapsed following a prior autograft and 13 had previously received bortezomib. Fifteen of them either remained stable or improved disease status at day +100 post‐transplant, including 11 patients with active disease. More specifically, nine patients (56%) and five patients (31%) reached complete remission and partial response, respectively. 25% developed grade III acute graft‐versus‐host disease. The cumulative incidence of non‐relapse mortality, relapse and overall survival were 25%, 54% and 41%, respectively, at 3 years. Regarding the non‐haematological toxicity (grade>2), two patients developed peripheral neuropathy, two patients liver toxicity and 1 pulmonary toxicity early post‐transplant. The haematological toxicity was only observed during the first three cycles mostly related to low haemoglobin and platelet levels. The current trial is the first one evaluating the safety and efficacy of bortezomib as part of a reduced intensity conditioning regimen among patients with high risk multiple myeloma.

Multiparameter flow cytometry for staging of solitary bone plasmacytoma: new criteria for risk of progression to myeloma

Solitary plasmacytoma represents a heterogeneous group of patients; approximately half develop multiple myeloma (MM) in 2 or 3 years, whereas others remain disease-free at 10 years. By definition, these patients do not have morphologic bone marrow (BM) plasma cell (PC) infiltration. Here, we investigated whether sensitive BM evaluation of patients with solitary bone plasmacytoma (SBP; n = 35) and extramedullary plasmacytoma (EMP; n = 29) through multiparameter flow cytometry (MFC) would unravel the presence of clonal PCs in otherwise disease-free BM, and whether BM clonality predicted higher risk of progression. BM clonal PCs were detected in 17 of 35 SBP (49%) and 11 of 29 EMP (38%) patients. Seventy-one percent of flow-positive vs only 8% of flow-negative SBP patients evolved to MM (median time to progression of 26 months vs not reached; hazard ratio, 17.4; P < .001). No significant differences were observed among EMP cases. Our results highlight the importance of MFC for sensitive BM evaluation of SBP patients, to predict risk of developing treatment-requiring MM and to plan disease monitoring.

Depletion of alloreactive T-cells in vitro using the proteasome inhibitor bortezomib preserves the immune response against pathogens

Current graft-versus-host disease (GVHD) inhibition approaches lead to abrogation of pathogen-specific T-cell responses. We propose an approach to inhibit GVHD without hampering immunity against pathogens: in vitro depletion of alloreactive T cells with the preoteasome inhibitor bortezomib. We show that PBMCs stimulated with allogeneic cells and treated with bortezomib greatly reduce their ability to produce IFN-γ when re-stimulated with the same allogeneic cells, but mainly preserve their ability to respond to citomegalovirus stimulation. Unlike in vivo administration of immunosuppressive drugs or other strategies of allodepletion, in vitro allodepletion with bortezomib maintains pathogen-specific T cells, representing a promising alternative for GVHD prophylaxis.

The novel combination of sirolimus and bortezomib prevents graft-versus-host disease but maintains the graft-versus-leukemia effect after allogeneic transplantation.

Background We have previously shown that bortezomib induces a depletion of alloreactive T cells and allows the expansion of T cells with suppressive properties. In the current study, we analyzed the potential synergistic effect of bortezomib in conjunction with sirolimus in order to reduce-graft-versus-host disease without hampering graft-versus-leukemia effect in the allogeneic transplant setting. Design and Methods We evaluated the effect of sirolimus, bortezomib or the combination of both in the proliferation and activation of in vitro stimulated T lymphocytes. Pathways involved in this synergy were also analyzed using Western blot assays. Finally, BALB/c mice receiving C57BL/6 allogeneic donor bone marrow with splenocytes were used to measure in vivo the effect of this novel combination on the risk of graft-versus-host disease. Results The combination of both drugs synergistically inhibited both activation and proliferation of stimulated T cells. Also, the production of Th1 cytokines (IFN γ, IL-2 and TNF) was significantly inhibited. This effect was due, at least in part, to the inhibition of Erk and Akt phosphorylation. In vivo, the combination reduced the risk of graft-versus-host disease without hampering graft-versus-leukemia effect, as shown in mice receiving graft-versus-host disease prophylaxis with sirolimus plus bortezomib being infused with tumor WEHI cells plus C57BL/6 donor BM and splenocytes. Conclusions The current study reveals a synergistic effect of the combination sirolimus and bortezomib to prevent graft-versus-host disease while maintaining the graft-versus-leukemia effect.

Evaluation of prognostic factors among patients with chronic graft-versus-host disease

Background Chronic graft-versus-host disease (cGVHD) is a major complication after allogeneic stem cell transplantation with an adverse effect on both mortality and morbidity. In 2005, the National Institute of Health proposed new criteria for diagnosis and classification of chronic graft-versus-host disease for clinical trials. New sub-categories were recognized such as late onset acute graft-versus-host disease and overlap syndrome. Design and Methods We evaluated the prognostic impact of the new sub-categories as well as the clinical scoring system proposed by the National Institute of Health in a retrospective, multicenter study of 820 patients undergoing allogeneic stem cell transplantation between 2000 and 2006 at 3 different institutions. Patients were retrospectively categorized according to the National Institute of Health criteria from patients’ medical histories. Results As far as the new sub-categories are concerned, in univariate analysis diagnosis of overlap syndrome adversely affected the outcome. Also, the number of organs involved for a cut-off value of 4 significantly influenced both cGVHD related mortality and survival. In multivariate analysis, in addition to NIH score, platelet count and performance score at the time of cGVHD diagnosis, plus gut involvement, significantly influenced outcome. These 3 variables allowed us to develop a simple score system which identifies 4 subgroups of patients with 84%, 64%, 43% and 0% overall survival at five years after cGVHD diagnosis (score 0: HR=15.96 (95% CI: 6.85–37.17), P<0.001; score 1: HR=5.47 (95% CI: 2.6–11.5), P<0.001; score 2: HR=2.8 (95% CI: 1.32–5.93), P=0.007). Conclusions In summary, we have identified a powerful and simple tool to discriminate different subgroups of patients in terms of chronic graft-versus-host disease related mortality and survival.

Caspase-8 inhibition represses initial human monocyte activation in septic shock model.

In septic patients, the onset of septic shock occurs due to the over-activation of monocytes. We tested the therapeutic potential of directly targeting innate immune cell activation to limit the cytokine storm and downstream phases. We initially investigated whether caspase-8 could be an appropriate target given it has recently been shown to be involved in microglial activation. We found that LPS caused a mild increase in caspase-8 activity and that the caspase-8 inhibitor IETD-fmk partially decreased monocyte activation. Furthermore, caspase-8 inhibition induced necroptotic cell death of activated monocytes. Despite inducing necroptosis, caspase-8 inhibition reduced LPS-induced expression and release of IL-1β and IL-10. Thus, blocking monocyte activation has positive effects on both the pro and anti-inflammatory phases of septic shock. We also found that in primary mouse monocytes, caspase-8 inhibition did not reduce LPS-induced activation or induce necroptosis. On the other hand, broad caspase inhibitors, which have already been shown to improve survival in mouse models of sepsis, achieved both. Thus, given that monocyte activation can be regulated in humans via the inhibition of a single caspase, we propose that the therapeutic use of caspase-8 inhibitors could represent a more selective alternative that blocks both phases of septic shock at the source.

Effect of vitamin D treatment in chronic GVHD

Currently, there is no standard approach for patients with chronic GVHD (cGVHD) who do not respond to or who relapse after first-line treatment, and rescue therapy is based on immunosuppressive drugs and glucocorticoids, which are responsible for the development of severe complications. Vitamin D (Vit D) has a potent immunomodulatory effect, as shown in vitro and in animal models, nevertheless there is no information about its use in the the cGVHD setting. We evaluated retrospectively the outcome of cGVHD in a series of 12 patients receiving vit D because of proved osteopenia or osteoporosis by bone densitometry after allo-HSCT. These patients also had active cGVHD at the time when vit D treatment was started. We observed a marked improvement in cGVHD for most of these patients, without appreciable secondary effects. Chronic GVHD was classified as limited versus extensive, and also the National Institutes of Health scoring system was used, based on the data collected from the medical files of the patients. The first-line treatment for cGVHD was CsA or tacrolimus plus prednisone at 1mg/kg per day, which was switched to alternating days after 4 weeks of treatment. Patient characteristics are summarized in Table 1. According to our standard procedures, patients undergoing allo-HSCT have a bone densitometry performed between 6 months and 1 year after transplantation to rule out osteopenia or osteoporosis. In case it is detected, then a dosage of vit D 1000 IU per day (oral) plus calcium carbonate 1250mg (one pill per os daily) are prescribed for at least 6 months. Chronic GVHD response was assessed according to National Institutes of Health response criteria at 3 and 6 months after the beginning of vit D plus calcium treatment. For skin involvement, a PR was considered to have occurred when at least 50% of the skin involvement appeared to be non-inflammatory or to be fixed, and for complete response, as either the disappearance of all lesions or the presence of fixed and pigmented lesions. Chronic GVHD was diagnosed at a median day of 147 after transplant (range: 119–491 days). At the time when vit D treatment was started, six patients had received one line of immunosuppressive treatment, three patients had received two lines of treatment, two patients had received three lines and one patient had received four lines of treatment. Seven patients had mild, two patients had moderate and three had severe cGVHD; organ involvement is summarized in Table 2. At 3 months after vit D treatment, three patients obtained complete response, six patients obtained PR and one patient had no response, with six patients displaying mild and one patient showing severe cGVHD. Finally, at 6 months after treatment, five patients obtained complete response, six patients obtained PR and one patient had no response, with six patients displaying mild and one of them showing moderate cGVHD. No immunosuppressive drugs were added to the treatment during this period. Interestingly, at the beginning of vit D treatment, 10 patients were receiving calcineurin inhibitors, one patient was receiving calcineurin inhibitor plus prednisone and one patient was receiving mofetil mycophenolate plus prednisone. After 6 months of vit D treatment, five patients were not receiving immunosuppressive drugs, whereas seven patients were receiving immunosuppressive treatment based on CsA or tacrolimus (with or without topical treatment in five patients and with other systemic immunosuppressive drug in two patients). We compared patients who received vit D and who had not previously relapsed (n1⁄4 6) with a cohort of 24 patients, transplanted during the same period of time, who had not received vit D and were on first-line treatment for cGVHD, and had similar characteristics regarding GVHD severity and extension. Interestingly, 50% of the patients receiving vit D were put off on immunosuppresion for 6 months after

Immunomodulatory Effect of Vitamin D after Allogeneic Stem Cell Transplantation: Results of a Prospective Multicenter Clinical Trial

Purpose: We describe the results of a prospective multicenter phase I/II trial evaluating the impact of the use of vitamin D (VitD) from day −5 to +100 on the outcome of patients undergoing allogeneic transplantation (EudraCT: 2010-023279-25; ClinicalTrials.gov: NCT02600988). Experimental Design: A total of 150 patients were included in three consecutive cohorts of 50 patients each group: control group (CG, not receive VitD); low-dose group (LdD, received 1,000 IU VitD daily); and high-dose group (HdD, 5,000 IU VitD daily). We measured levels of VitD, cytokines, and immune subpopulations after transplantation. Results: No significant differences were observed in terms of cumulative incidence of overall and grades 2–4 acute GVHD in terms of relapse, nonrelapse mortality, and overall survival. However, a significantly lower cumulative incidence of both overall and moderate plus severe chronic GVHD (cGVHD) at 1 year was observed in LdD (37.5% and 19.5%, respectively) and HdD (42.4% and 27%, respectively) as compared with CG (67.5% and 44.7%, respectively; P < 0.05). In multivariable analysis, treatment with VitD significantly decreased the risk of both overall (for LdD: HR = 0.31, P = 0.002; for HdD: HR = 0.36, P = 0.006) and moderate plus severe cGVHD (for LdD: HR = 0.22, P = 0.001; for HdD: HR = 0.33, P = 0.01). VitD modified the immune response, decreasing the number of B cells and naïve CD8 T cells, with a lower expression of CD40L. Conclusions: This is the first prospective trial that analyzes the effect of VitD postransplant. We observed a significantly lower incidence of cGVHD among patients receiving VitD. Interestingly, VitD modified the immune response after allo-SCT. Clin Cancer Res; 22(23); 5673–81. ©2016 AACR.