Experimental Hematology & Oncology最新文献

Cellular immunotherapy, particularly CAR-T cells, has shown potential in the improvement of outcomes in patients with refractory and recurrent malignancies of the blood. However, achieving sustainable long-term complete remission for blood cancer remains a challenge, with resistance and relapse being expected outcomes for many patients. Although many studies have attempted to clarify the mechanisms of CAR-T cell therapy failure, the mechanism remains unclear. In this article, we discuss and describe the current state of knowledge regarding these factors, which include elements that influence the CAR-T cell, cancer cells as a whole, and the microenvironment surrounding the tumor. In addition, we propose prospective approaches to overcome these obstacles in an effort to decrease recurrence rates and extend patient survival subsequent to CAR-T cell therapy.

Natural killer (NK) cell belongs to innate lymphoid cell family that contributes to host immunosurveillance and defense without pre-immunization. Emerging studies have sought to understand the underlying mechanism behind NK cell dysfunction in tumor environments, and provide numerous novel therapeutic targets for tumor treatment. Strategies to enhance functional activities of NK cell have exhibited promising efficacy and favorable tolerance in clinical treatment of tumor patients, such as immune checkpoint blockade (ICB), chimeric antigen receptor NK (CAR-NK) cell, and bi/trispecific killer cell engager (BiKE/TriKE). Immunotherapy targeting NK cell provides remarkable advantages compared to T cell therapy, including a decreased rate of graft versus-host disease (GvHD) and neurotoxicity. Nevertheless, advanced details on how to support the maintenance and function of NK cell to obtain better response rate and longer duration still remain to be elucidated. This review systematically summarizes the profound role of NK cells in tumor development, highlights up-to-date advances and current challenges of therapy targeting NK cell in the clinical treatment of hematologic malignancies.

Background: Ferroptosis is a new form of nonapoptotic and iron-dependent type of cell death. Glutathione peroxidase-4 (GPX4) plays an essential role in anti-ferroptosis by reducing lipid peroxidation. Although acute myeloid leukemia (AML) cells, especially relapsed and refractory (R/R)-AML, present high GPX4 levels and enzyme activities, pharmacological inhibition of GPX4 alone has limited application in AML. Thus, whether inhibition of GPX4 combined with other therapeutic reagents has effective application in AML is largely unknown.

Methods: Lipid reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) assays were used to assess ferroptosis in AML cells treated with the hypomethylating agent (HMA) decitabine (DAC), ferroptosis-inducer (FIN) RAS-selective lethal 3 (RSL3), or their combination. Combination index (CI) analysis was used to assess the synergistic activity of DAC + RSL3 against AML cells. Finally, we evaluated the synergistic activity of DAC + RSL3 in murine AML and a human R/R-AML-xenografted NSG model in vivo.

Results: We first assessed GPX4 expression and found that GPX4 levels were higher in AML cells, especially those with MLL rearrangements, than in NCs. Knockdown of GPX4 by shRNA and indirect inhibition of GPX4 enzyme activity by RSL3 robustly induced ferroptosis in AML cells. To reduce the dose of RSL3 and avoid side effects, low doses of DAC (0.5 µM) and RSL3 (0.05 µM) synergistically facilitate ferroptosis by inhibiting the AMP-activated protein kinase (AMPK)-SLC7A11-GPX4 axis. Knockdown of AMPK by shRNA enhanced ferroptosis, and overexpression of SLC7A11 and GPX4 rescued DAC + RSL3-induced anti-leukemogenesis. Mechanistically, DAC increased the expression of MAGEA6 by reducing MAGEA6 promoter hypermethylation. Overexpression of MAGEA6 induced the degradation of AMPK, suggesting that DAC inhibits the AMPK-SLC7A11-GPX4 axis by increasing MAGEA6 expression. In addition, DAC + RSL3 synergistically reduced leukemic burden and extended overall survival compared with either DAC or RSL3 treatment in the MLL-AF9-transformed murine model. Finally, DAC + RSL3 synergistically reduced viability in untreated and R/R-AML cells and extended overall survival in two R/R-AML-xenografted NSG mouse models.

Conclusions: Our study first identify vulnerability to ferroptosis by regulating MAGEA6-AMPK-SLC7A11-GPX4 signaling pathway. Combined treatment with HMAs and FINs provides a potential therapeutic choice for AML patients, especially for R/R-AML.

Background: Mixed-lineage leukemia (MLL) fusion gene caused by chromosomal rearrangement is a dominant oncogenic driver in leukemia. Due to having diverse MLL rearrangements and complex characteristics, MLL leukemia treated by currently available strategies is frequently associated with a poor outcome. Therefore, there is an urgent need to identify novel therapeutic targets for hematological malignancies with MLL rearrangements.

Methods: qRT-PCR, western blot, and spearman correction analysis were used to validate the regulation of LAMP5-AS1 on LAMP5 expression. In vitro and in vivo experiments were conducted to assess the functional relevance of LAMP5-AS1 in MLL leukemia cell survival. We utilized chromatin isolation by RNA purification (ChIRP) assay, RNA pull-down assay, chromatin immunoprecipitation (ChIP), RNA fluorescence in situ hybridization (FISH), and immunofluorescence to elucidate the relationship among LAMP5-AS1, DOT1L, and the LAMP5 locus. Autophagy regulation by LAMP5-AS1 was evaluated through LC3B puncta, autolysosome observation via transmission electron microscopy (TEM), and mRFP-GFP-LC3 puncta in autophagic flux.

Results: The study shows the crucial role of LAMP5-AS1 in promoting MLL leukemia cell survival. LAMP5-AS1 acts as a novel autophagic suppressor, safeguarding MLL fusion proteins from autophagic degradation. Knocking down LAMP5-AS1 significantly induced apoptosis in MLL leukemia cell lines and primary cells and extended the survival of mice in vivo. Mechanistically, LAMP5-AS1 recruits the H3K79 histone methyltransferase DOT1L to LAMP5 locus, directly activating LAMP5 expression. Importantly, blockade of LAMP5-AS1-LAMP5 axis can represses MLL fusion proteins by enhancing their degradation.

Conclusions: The findings underscore the significance of LAMP5-AS1 in MLL leukemia progression through the regulation of the autophagy pathway. Additionally, this study unveils the novel lncRNA-DOT1L-LAMP5 axis as promising therapeutic targets for degrading MLL fusion proteins.

Patients with relapsed or refractory (R/R) acute myeloid leukemia (AML) often exhibit limited responses to traditional chemotherapy, resulting in poor prognosis. The combination of venetoclax (VEN) with hypomethylating agents has been established as the standard treatment for elderly or medically unfit AML patients unable to undergo intensive chemotherapy. Despite this, the availability of novel VEN-based therapies specifically tailored for those with R/R AML remains scarce. Here, we provide a comprehensive overview of the latest data presented at the 65th American Society of Hematology Annual Meeting, shedding light on the progress and efficacy of VEN-based therapies for R/R AML.

The 2022 European LeukemiaNet (ELN) updated the previous risk classification published in 2017 but the prognostic significance for allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. We enrolled 600 acute myeloid leukemia (AML) patients who underwent allo-HSCT to validate ELN-2022 genetic risk system and compared it with ELN-2017. There were 214 (35.67%), 162 (27.0%), and 224 (37.33%) patients in ELN-2022 favorable-, intermediate-, and adverse-risk group respectively and 86 patients (14.33%) experienced a shift in risk stratification compared to ELN-2017. Median and maximum follow-up time were 2.89 (95% CI 2.67 to 3.03) years and 8.78 years. The median overall survival (OS) was 73.8% (95% CI 67.5% to 80.3%), 63.9% (95% CI 56.7% to 72.0%) and 57.6% (95% CI 50.4% to 65.9%) in ELN-2022 favorable-, intermediate-, and adverse-risk group (P < 0.001). OS shortened significantly as the ELN-2022 risk stratification increased but didn't significantly in ELN-2017 intermediate-risk compared to favorable-risk. Both ELN-2022 and ELN-2017 adverse-risk were associated with increased cumulative incidence of relapse (CIR). Time-dependent receiver operating characteristic (ROC) analysis showed that both ELN-2017 and ELN-2022 risk systems had limited prognostic ability for OS. We modified ELN-2022 risk system with pre-transplant minimal residual disease (MRD) and the modified risk system performed a significantly superior efficacy to ELN-2022 system.

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death globally. Although the gut microbiota's role in the antitumor efficacy of many cancers has been revealed, its involvement in the response to gefitinib therapy for LUAD remains unclear. To fill this gap, we conducted a longitudinal study that profiled gut microbiota changes in PC-9 tumor-bearing mice under different treatments, including gefitinib monotherapy and combination therapies with probiotics, antibiotics, or Traditional Chinese Medicine (TCM). Our findings demonstrated that combining probiotics or TCM with gefitinib therapy outperformed gefitinib monotherapy, as evidenced by tumor volume, body weight, and tumor marker tests. By contrast, antibiotic intervention suppressed the antitumor efficacy of gefitinib. Notably, the temporal changes in gut microbiota were strongly correlated with the different treatments, prompting us to investigate whether there is a causal relationship between gut microbiota and the antitumor efficacy of gefitinib using Mediation Analysis (MA). Finally, our research revealed that thirteen mediators (Amplicon Sequence Variants, ASVs) regulate the antitumor effect of gefitinib, regardless of treatment. Our study provides robust evidence supporting the gut microbiota's significant and potentially causal role in mediating gefitinib treatment efficacy in mice. Our findings shed light on a novel strategy for antitumor drug development by targeting the gut microbiota.

Brexucabtagene autoleucel CAR-T therapy is highly efficacious in overcoming resistance to Bruton's tyrosine kinase inhibitors (BTKi) in mantle cell lymphoma. However, many patients relapse post CAR-T therapy with dismal outcomes. To dissect the underlying mechanisms of sequential resistance to BTKi and CAR-T therapy, we performed single-cell RNA sequencing analysis for 66 samples from 25 patients treated with BTKi and/or CAR-T therapy and conducted in-depth bioinformatics™ analysis. Our analysis revealed that MYC activity progressively increased with sequential resistance. HSP90AB1 (Heat shock protein 90 alpha family class B member 1), a MYC target, was identified as early driver of CAR-T resistance. CDK9 (Cyclin-dependent kinase 9), another MYC target, was significantly upregulated in Dual-R samples. Both HSP90AB1 and CDK9 expression were correlated with MYC activity levels. Pharmaceutical co-targeting of HSP90 and CDK9 synergistically diminished MYC activity, leading to potent anti-MCL activity. Collectively, our study revealed that HSP90-MYC-CDK9 network is the primary driving force of therapeutic resistance.