Outcome improvement over time in reduced intensity conditioning hematopoietic transplantation: a 20-year experience.

The current study includes all consecutive patients (N = 484) who received a reduced-intensity conditioning regimen (RIC) allogeneic hematopoietic stem cell transplantation in our center from 1999 to 2020. Conditioning regimens were based on fludarabine with melphalan or busulfan, with low-dose thiotepa and pharmacological GVHD prophylaxis consisted of cyclosporine A (CsA)-methotrexate (MTX)/mofetil (MMF) (n = 271), tacrolimus-sirolimus (n = 145), and post-transplantation cyclophosphamide (PTCy)-tacrolimus (n = 68). The median time of overall follow-up in survivors was 8 years (1-22 years) and was at least 3 years in all three GVHD prophylaxis groups. Thirty-three percent had a high or very high disease risk index, 56% ≥ 4 European bone marrow transplantation risk, and 65% ≥ 3 hematopoietic stem cell transplantation comorbidity index score-age score. Neutrophil and platelet engraftment was longer for PTCy-tacro (p 0.0001). Cumulative incidence of grade III-IV aGVHD was 17% at 200 days, and that of moderate-severe cGvHD was 36% at 8 years. GVHD prophylaxis was the only prognostic factor in the multivariable analyses for the development of aGVHD and moderate-severe cGVHD (p 0.0001). NRM and relapse incidences were 29% and 30% at 8 years, while OS and PFS rates were 43% and 39% at 8 years. At 3 years, OS was highest in the PTCy-tacro group (68%) than in the tacro-siro (61%) and CsA-MTX/MMF (49%) cohorts (p < 0.01). In the three groups, respectively, the 200-day incidence of grade III-IV aGvHD (6% vs. 12% vs. 23%) and 3-year moderate-severe cGVHD (8% vs. 40% vs. 38%) were lower in the PTCy cohort. These better outcomes were confirmed in multivariable analyses. Based on our recent results, the PTCy could be considered as a real GvHD prophylaxis in the RIC setting due to improve best 3-year GvHD and survival outcomes.

Endoglin, a Novel Biomarker and Therapeutical Target to Prevent Malignant Peripheral Nerve Sheath Tumor Growth and Metastasis.

PURPOSE: Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive soft-tissue sarcomas that lack effective treatments, underscoring the urgent need to uncover novel mediators of MPNST pathogenesis that may serve as potential therapeutic targets. Tumor angiogenesis is considered a critical event in MPNST transformation and progression. Here, we have investigated whether endoglin (ENG), a TGFß coreceptor with a crucial role in angiogenesis, could be a novel therapeutic target in MPNSTs. EXPERIMENTAL DESIGN: ENG expression was evaluated in human peripheral nerve sheath tumor tissues and plasma samples. Effects of tumor cell-specific ENG expression on gene expression, signaling pathway activation and in vivo MPNST growth and metastasis, were investigated. The efficacy of ENG targeting in monotherapy or in combination with MEK inhibition was analyzed in xenograft models. RESULTS: ENG expression was found to be upregulated in both human MPNST tumor tissues and plasma-circulating small extracellular vesicles. We demonstrated that ENG modulates Smad1/5 and MAPK/ERK pathway activation and pro-angiogenic and pro-metastatic gene expression in MPNST cells and plays an active role in tumor growth and metastasis in vivo. Targeting with ENG-neutralizing antibodies (TRC105/M1043) decreased MPNST growth and metastasis in xenograft models by reducing tumor cell proliferation and angiogenesis. Moreover, combination of anti-ENG therapy with MEK inhibition effectively reduced tumor cell growth and angiogenesis. CONCLUSIONS: Our data unveil a tumor-promoting function of ENG in MPNSTs and support the use of this protein as a novel biomarker and a promising therapeutic target for this disease.

Evolution in the frontline treatment of patients with chronic lymphocytic leukemia: experience from one European center.

Treatment of chronic lymphocytic leukemia (CLL) has dramatically evolved over the last decades thanks to the introduction of targeted therapies. We aimed to describe retrospectively the evolution in the frontline prescription in the CLL patients from our institution. As a secondary objective, the impact of frontline therapy on the time-to-next-treatment (TTNT) and overall survival (OS). After a median of 6.4 years (0.1-36.4) of follow-up from diagnosis, 323 of 780 CLL patients (41.4%) required therapy. Alkylating agents in monotherapy (chlorambucil) were the most used until 2012, and from then, chemoimmunotherapy. Since 2018, targeted therapies were the most common therapeutic strategy (74.1%). Patients who received targeted therapies had significantly longer TTNT compared to other regimens. In the multivariable analyses, mutated IGHV genes targeted therapies and chemoimmunotherapy regimens were related to longer TTNT, and sex female, age younger than 65, and mutated IGHV genes were associated with better OS.

Sequence matters: Total body irradiation (TBI)-based myeloablative conditioning with post-transplant cyclophosphamide may reduce the early nonrelapse mortality compared with pretransplant cyclophosphamide plus TBI.

OBJECTIVES: High-dose total body irradiation (TBI) is considered a cornerstone of myeloablative conditioning for allogeneic stem cell transplantation (allo-SCT). We retrospectively compared the main outcomes of an HLA matched or 1-allele mismatched related or unrelated allo-SCT in adult patients affected by acute leukemia (AL) or myelodysplastic syndromes (MDS). METHODS: Fifty-nine patients received cyclophosphamide (Cy)-TBI (13.5 Gy) and graft-versus-host disease (GVHD) prophylaxis with a calcineurin-inhibitor plus methrotrexate (CyTBI group) and 28 patients received fludarabine-TBI (8.8-13.5 Gy) and GVHD prophylaxis with PTCy and tacrolimus (FluTBI-PTCy group). RESULTS: Median follow-up for survivors was 82 and 22 months. The 12-month probability of overall survival and progression-free survival were similar (p = .18, p = .7). The incidence of Grades 2-4 and 3-4 acute GVHD, and the incidence of moderate-to-severe chronic GVHD were higher in the CyTBI group (p = .02, p < .01and p = .03). Nonrelapse mortality (NRM) at 12 months posttransplant was higher in the CyTBI group (p = 0.05), while the incidence of relapse was similar in both groups (p = 0.7). The number of GVHD-free and relapse-free patients without systemic immunosuppression (GRFS) at 1-year posttransplant was higher in the FluTBI-PTCy group (p = 0.01). CONCLUSIONS: The study confirms the safety and efficacy of a novel FluTBI-PTCy platform with reduced incidence of severe acute and chronic GVHD, and early improvement of NRM.

Successful Outcome in Patients with Myelofibrosis Undergoing Allogeneic Donor Hematopoietic Cell Transplantation Using Reduced Doses of Post-Transplantation Cyclophosphamide: Challenges and Review of the Literature.

Engraftment and nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation (allo-HCT) depend greatly on the transplantation platform in patients with myelofibrosis (MF). We report outcomes of 14 consecutive MF patients who received reduced doses of post-transplantation cyclophosphamide (PTCy; 60 mg/kg total dose) and tacrolimus as graft-versus-host disease (GVHD) prophylaxis as part of a new standardized allo-HCT protocol. The median patient age at allo-HCT was 59 years (range, 41 to 67 years), and the median interval from diagnosis to HCT was 19 months (range, 2 to 114 months). All patients received ruxolitinib before HCT, and 71% had no response. Most patients (78%) had symptomatic splenomegaly at HCT. Eighty-six percent received reduced-intensity conditioning, and 64% underwent allo-HCT from an unrelated donor. There were no graft failures, and neutrophil and platelet recovery occurred at a median of 21 days and 31 days, respectively. The cumulative incidence of grade II-IV acute GVHD was 28.6%, and that of grade III-IV acute GVHD was 7%. The 2-year incidence of overall and moderate-severe chronic GVHD was 36% and 14%, respectively. Only 1 patient relapsed after transplantation, and NRM was 7% at 100 days and 14% at 2 years. The GVHD-free/relapse-free and immunosuppression-free incidence at 1 year was 41%. With a median follow-up for survivors of 28 months (range, 8 to 55 months), the 2-year overall survival and progression-free survival were 86% and 69%, respectively. Reduced doses of PTCy as GVHD prophylaxis for high-risk MF patients showed promising results by reducing the incidence of GVHD without any cases of graft failure.

Feasibility of a New Model of Care for Allogeneic Stem Cell Transplantation Recipients Facilitated by eHealth: The MY-Medula Pilot Study.

The use of allogeneic stem cell transplantation (allo-SCT) for the treatment of hematologic diseases is steadily increasing; however, allo-SCT has the downside of causing considerable treatment-related morbidity and mortality. Mobile technology applied to healthcare (mHealth) has proven to be a cost-effective strategy to improve care and offer new services to people with multimorbidity, but there are little data on its usefulness in allo-SCT recipients. Here we describe a new integrated healthcare model facilitated by an mHealth platform, EMMASalud-MY-Medula, and to report the results of a feasibility and usability pilot study. The MY-Medula platform was developed in 4 phases. First, patient and healthcare professional needs were identified, and technological development and pretesting tests were conducted (phases 1 to 3, January 2016 to March 2021). Then a nonrandomized, prospective, observational, single-center pilot study was conducted (October 2021 to January 2022) at the adult SCT unit of a tertiary university hospital. Twenty-eight volunteer allo-SCT recipients were included in the pilot study, of whom one-half were outpatients in the first-year post-SCT and one-half were affected by steroid-dependent graft-versus-host disease (SR-GVHD). All patients used the MY-Medula app during the 2-month follow-up period, with a median number of visits to the app of 143 (range, 6 to 477). A total of 2067 self-monitoring records were created, and 205 text messages were received, most of them related to symptoms description (47%) and doubts about medication (21%). In 3.4% of the cases, drug dosage was adjusted by the pharmacist because of dosing errors or interactions. At the end of the study, a 6-question Likert-type questionnaire for patients and a 22-question test for healthcare professionals showed a high degree of satisfaction (95% and 100%, respectively) with the new healthcare pathway. Reengineering the follow-up of allo-SCT recipients into an integrated, multidisciplinary model of care facilitated by mHealth tools is feasible and has been associated with high usability and a high degree of satisfaction by patients and healthcare professionals. A randomized trial aiming to determine the cost-effectiveness of MY-Medula-based follow-up post-SCT is currently enrolling participants.

BRAF activation by metabolic stress promotes glycolysis sensitizing NRASQ61-mutated melanomas to targeted therapy.

NRAS-mutated melanoma lacks a specific line of treatment. Metabolic reprogramming is considered a novel target to control cancer; however, NRAS-oncogene contribution to this cancer hallmark is mostly unknown. Here, we show that NRASQ61-mutated melanomas specific metabolic settings mediate cell sensitivity to sorafenib upon metabolic stress. Mechanistically, these cells are dependent on glucose metabolism, in which glucose deprivation promotes a switch from CRAF to BRAF signaling. This scenario contributes to cell survival and sustains glucose metabolism through BRAF-mediated phosphorylation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-2/3 (PFKFB2/PFKFB3). In turn, this favors the allosteric activation of phosphofructokinase-1 (PFK1), generating a feedback loop that couples glycolytic flux and the RAS signaling pathway. An in vivo treatment of NRASQ61 mutant melanomas, including patient-derived xenografts, with 2-deoxy-D-glucose (2-DG) and sorafenib effectively inhibits tumor growth. Thus, we provide evidence for NRAS-oncogene contributions to metabolic rewiring and a proof-of-principle for the treatment of NRASQ61-mutated melanoma combining metabolic stress (glycolysis inhibitors) and previously approved drugs, such as sorafenib.

Characterization of plasma circulating small extracellular vesicles in patients with metastatic solid tumors and newly diagnosed brain metastasis.

Nearly 40% of the advanced cancer patients will present brain metastases during the course of their disease, with a 2-year life expectancy of less than 10%. Immune system impairment, including the modulation of both STAT3 and PD-L1, is one of the hallmarks of brain metastases. Liquid biopsy could offer several advantages in brain metastases management, such as the possibility of noninvasive dynamic monitoring. Extracellular vesicles (EVs) have been recently proposed as novel biomarkers especially useful in liquid biopsy due to their secretion in biofluids and their role in cell communication during tumor progression. The main aim of this work was to characterize the size and protein cargo of plasma circulating EVs in patients with solid tumors and their correlation with newly diagnosed brain metastases, in addition to their association with other relevant clinical variables. We analyzed circulating EVs in the plasma of 123 patients: 42 patients with brain metastases, 50 without brain metastases and 31 healthy controls. Patients with newly diagnosed brain metastases had a lower number of circulating EVs in the plasma and a higher protein concentration in small EVs (sEVs) compared to patients without brain metastases and healthy controls. Interestingly, melanoma patients with brain metastases presented decreased STAT3 activation and increased PD-L1 levels in circulating sEVs compared to patients without central nervous system metastases. Decreased STAT3 activation and increased PD-L1 in plasma circulating sEVs identify melanoma patients with brain metastasis.

Efficacy and Safety of Ruxolitinib in Steroid-Refractory/Dependent Chronic Graft-versus-Host Disease: Real-World Data and Challenges.

Steroid-refractory (SR) chronic graft-versus-host disease (cGVHD) is a major obstacle in recipients of allogeneic stem cell transplantation (HCT). Ruxolitinib is the first agent to demonstrate superior efficacy to the best available therapy, but real-life data are still lacking. Here we describe the results of ruxolitinib compassionate use for the treatment of SR/steroid-dependent cGVHD in a tertiary care university hospital. In this retrospective single-center study, we evaluated the outcomes of 48 patients diagnosed with SR-cGVHD who were treated with ruxolitinib. Forty-seven (98%) had moderate-severe disease, and 27 (56%) had received ≥2 lines of prior therapy (excluding steroids). Results were analyzed using SPSS version 26.0.01 and R version 3.4.3. The overall response rate was 77% (37 of 48), with 15% (7 of 37) in complete remission. The median time to response was 2 months (range, 0.5 to 8 months). Steroid tapering was achieved in 26 patients (54%) and definitive discontinuation was achieved in 10 patients (21%) after a median of 20 months (range, 1.5 to 60 months). Toxicity was predominantly hematologic, including a 33% rate of anemia and a 17% rate of thrombocytopenia. Overall survival at 2 years was significantly higher in responders compared with nonresponders (88% [95% confidence interval (CI), 65% to 96%] versus 49% [95% CI, 12% to 78%]; P = .01). At last follow-up, tapering of ruxolitinib had been started in 8 of 37 responders (22%). Our experience supports the efficacy of ruxolitinib in the treatment of SR-cGVHD, along with its steroid-sparing effect and manageable toxicity. Gradual tapering of ruxolitinib seems feasible without cases of GVHD flare. More studies and longer follow-up are needed to confirm these data, as well as to identify the ideal dose adjustments in cases of toxicity.

Melanoma-derived small extracellular vesicles induce lymphangiogenesis and metastasis through an NGFR-dependent mechanism.

Secreted extracellular vesicles (EVs) influence the tumor microenvironment and promote distal metastasis. Here, we analyzed the involvement of melanoma-secreted EVs in lymph node pre-metastatic niche formation in murine models. We found that small EVs (sEVs) derived from metastatic melanoma cell lines were enriched in nerve growth factor receptor (NGFR, p75NTR), spread through the lymphatic system and were taken up by lymphatic endothelial cells, reinforcing lymph node metastasis. Remarkably, sEVs enhanced lymphangiogenesis and tumor cell adhesion by inducing ERK kinase, nuclear factor (NF)-κB activation and intracellular adhesion molecule (ICAM)-1 expression in lymphatic endothelial cells. Importantly, ablation or inhibition of NGFR in sEVs reversed the lymphangiogenic phenotype, decreased lymph node metastasis and extended survival in pre-clinical models. Furthermore, NGFR expression was augmented in human lymph node metastases relative to that in matched primary tumors, and the frequency of NGFR+ metastatic melanoma cells in lymph nodes correlated with patient survival. In summary, we found that NGFR is secreted in melanoma-derived sEVs, reinforcing lymph node pre-metastatic niche formation and metastasis.

Ibrutinib effect in acquired von Willebrand syndrome secondary to Waldenström macroglobulinemia.

The pathological increase of clonal IgM in Waldenström macroglobulinemia can be associated with acquired von Willebrand syndrome and can be a major risk of bleeding symptoms in this subgroup of patients with Waldenström macroglobulinemia. The Bruton tyrosine kinase inhibitor ibrutinib is one of the approved treatments for symptomatic Waldenström macroglobulinemia. However, some controversy exists regarding the use of ibrutinib in these patients with high risk of bleeding because of its antiaggregant effect that could increase the risk of bleeding. Here, we present the case of a patient with Waldenström macroglobulinemia with associated acquired von Willebrand syndrome and progressively significant bleeding symptoms, who experienced a rapid increase in von Willebrand factor with ibrutinib treatment, despite only reaching a partial response in IgM levels similar to those reached with other previous treatments. We suggest that the control over the monoclonal protein is not the only mechanism that explains the good response, improvement in the bleeding symptoms and von Willebrand factor levels. This fact could be explained by the reduced glycoprotein Ib receptor expression induced by ibrutinib and the consequent von Willebrand factor increase in peripheral blood.

Publisher Correction: ITGB3-mediated uptake of small extracellular vesicles facilitates intercellular communication in breast cancer cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

ITGB3-mediated uptake of small extracellular vesicles facilitates intercellular communication in breast cancer cells.

Metastasis, the spread of malignant cells from a primary tumour to distant sites, causes 90% of cancer-related deaths. The integrin ITGB3 has been previously described to play an essential role in breast cancer metastasis, but the precise mechanisms remain undefined. We have now uncovered essential and thus far unknown roles of ITGB3 in vesicle uptake. The functional requirement for ITGB3 derives from its interactions with heparan sulfate proteoglycans (HSPGs) and the process of integrin endocytosis, allowing the capture of extracellular vesicles and their endocytosis-mediated internalization. Key for the function of ITGB3 is the interaction and activation of focal adhesion kinase (FAK), which is required for endocytosis of these vesicles. Thus, ITGB3 has a central role in intracellular communication via extracellular vesicles, proposed to be critical for cancer metastasis.

Dual disruption of aldehyde dehydrogenases 1 and 3 promotes functional changes in the glutathione redox system and enhances chemosensitivity in nonsmall cell lung cancer.

Aldehyde dehydrogenases (ALDHs) are multifunctional enzymes that oxidize diverse endogenous and exogenous aldehydes. We conducted a meta-analysis based on The Cancer Genome Atlas and Gene Expression Omnibus data and detected genetic alterations in ALDH1A1, ALDH1A3, or ALDH3A1, 86% of which were gene amplification or mRNA upregulation, in 31% of nonsmall cell lung cancers (NSCLCs). The expression of these isoenzymes impacted chemoresistance and shortened survival times in patients. We hypothesized that these enzymes provide an oxidative advantage for the persistence of NSCLC. To test this hypothesis, we used genetic and pharmacological approaches with DIMATE, an irreversible inhibitor of ALDH1/3. DIMATE showed cytotoxicity in 73% of NSCLC cell lines tested and demonstrated antitumor activity in orthotopic xenografts via hydroxynonenal-protein adduct accumulation, GSTO1-mediated depletion of glutathione and increased H2O2. Consistent with this result, ALDH1/3 disruption synergized with ROS-inducing agents or glutathione synthesis inhibitors to trigger cell death. In lung cancer xenografts with high to moderate cisplatin resistance, combination treatment with DIMATE promoted strong synergistic responses with tumor regression. These results indicate that NSCLCs with increased expression of ALDH1A1, ALDH1A3, or ALDH3A1 may be targeted by strategies involving inhibitors of these isoenzymes as monotherapy or in combination with chemotherapy to overcome patient-specific drug resistance.

Use of extracellular vesicles from lymphatic drainage as surrogate markers of melanoma progression and BRAF V600E mutation.

Liquid biopsies from cancer patients have the potential to improve diagnosis and prognosis. The assessment of surrogate markers of tumor progression in circulating extracellular vesicles could be a powerful non-invasive approach in this setting. We have characterized extracellular vesicles purified from the lymphatic drainage also known as exudative seroma (ES) of stage III melanoma patients obtained after lymphadenectomy. Proteomic analysis showed that seroma-derived exosomes are enriched in proteins resembling melanoma progression. In addition, we found that the BRAFV600E mutation can be detected in ES-derived extracellular vesicles and its detection correlated with patients at risk of relapse.

A BCR-ABL1 cutoff of 1.5% at 3 months, determined by the GeneXpert system, predicts an optimal response in patients with chronic myeloid leukemia.

In chronic myeloid leukemia (CML) patients, 3-month BCR-ABL1 levels have consistently been correlated with further outcomes. Monitoring molecular responses in CML using the GeneXpert (Cepheid) platform has shown an optimal correlation with standardized RQ-PCR (IS) when measuring BCR-ABL1 levels lower than 10%, as it is not accurate for values over 10%. The aim of the present study was to determine the predictive molecular value at three months on different outcome variables using the Xpert BCR-ABL1 MonitorTM assay (Xpert BCR-ABL1). We monitored 125 newly diagnosed consecutive CML patients in the chronic phase (CML-CP) using an automated method: Xpert BCR-ABL1. Only 5% of patients did not achieve an optimal response at 3 months, and the 10% BCR-ABL1 cutoff defined by RQ-PCR (IS) methods was unable to identify significant differences in the probabilities of achieving a complete cytogenetic response (CCyR) (50% vs. 87%, p = 0.1) or a major molecular response (MMR) (60% vs. 80%, p = 0.29) by 12 months. In contrast, a cutoff of 1.5% more accurately identified differences in the probabilities of achieving CCyR (98% vs. 54%, p<0.001) and MMR (88% vs. 56%, p<0.001) by 12 months, as well as probabilities of treatment changes (p = 0.005). Therefore, when using the Xpert BCR-ABL1 assay, a cutoff of 1.5% at 3 months could with high probability identify patients able to achieve an optimal response at 12 months.

Imatinib dose reduction in patients with chronic myeloid leukemia in sustained deep molecular response.

To determine whether a lower imatinib dose could minimize toxicity while maintaining the molecular response (MR), imatinib dose was reduced to 300 mg daily in 43 patients with chronic myeloid leukemia (CML) in sustained deep molecular response to first-line imatinib 400 mg daily. At the time of dose reduction, median duration of the deep response was 4.1 (interquartile range (IQR) 2.2-5.9) years; molecular response was MR4, MR4.5, and MR5 of the international scale in 6, 28, and 9 patients, respectively. Toxicity grade was 1, 2, and 3 in 28, 8, and 1 patients, respectively; 6 patients underwent dose reduction without having side effects. With a median of 1.6 (IQR 0.7-3.2) years on imatinib 300 mg daily, only one patient lost the deep molecular response to MR3. At the last follow-up, response was MR3, MR4, MR4.5, and MR5 in 1, 3, 9, and 30 patients, respectively. Toxicity improvement was observed in 23 (62.2 %) of the 37 patients with side effects, decreasing to grade 0 in 20 of them. All but one anemic patients improved (p = 0.01), the median Hb increase in this subgroup of patients being 1 g/dL. In CML patients with sustained deep response to the standard imatinib dose, reducing to 300 mg daily significantly improves tolerability and preserves efficacy.

Allopregnanolone prevents dieldrin-induced NMDA receptor internalization and neurotoxicity by preserving GABA(A) receptor function.

Dieldrin is an endocrine disruptor that accumulates in mammalian adipose tissue and brain. It induces convulsions due to its antagonism of the γ-aminobutyric acid A receptor (GABA(A)R). We have previously reported that long-term exposure to dieldrin causes the internalization of the N-methyl-D-aspartate receptor (NMDAR) as a result of persistent GABA(A)R inhibition. Because the neurosteroids 17ß-estradiol (E2) and allopregnanolone are known to modulate the function and trafficking of GABA(A)R and NMDAR, we examined the effects of E2 and allopregnanolone on dieldrin-induced GABA(A)R inhibition, NMDAR internalization, and neuronal death in cortical neurons. We found that 1 nM E2 increased the membrane expression of NR1/NR2B receptors and postsynaptic density 95 but did not induce their physical association. In contrast, 10 nM E2 had no effect on these proteins but reduced NR2A membrane expression. We also found that exposure to 60 nM dieldrin for 6 d in vitro caused the internalization of NR1 and NR2B but not NR2A. Treatment with either 1 nM E2 or 10 µM allopregnanolone prevented the dieldrin-induced reduction in membrane levels of the NR1/NR2B receptors. Furthermore, prolonged exposure to 200 nM dieldrin down-regulated the expression of NR2A; this was inhibited only by allopregnanolone. Although both hormones restored NMDAR function, as measured by the NMDA-induced rise in intracellular calcium, allopregnanolone (but not E2) reversed the inhibition of GABA(A)R and neuronal death caused by prolonged exposure to dieldrin. Our results indicate that allopregnanolone protects cortical neurons against the neurotoxicity caused by long-term exposure to dieldrin by maintaining GABA(A)R and NMDAR functionality.