Clinical efficacy and molecular biomarkers in a phase II study of tucidinostat plus R-CHOP in elderly patients with newly diagnosed diffuse large B-cell lymphoma

Rituximab-Chidamide combination chemotherapy enhances autophagy to overcome drug resistance in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a challenging malignancy, particularly when resistance to standard therapies such as Rituximab develops. This study investigates the combined therapeutic effects of Rituximab and Chidamide on DLBCL, focusing on drug resistance mechanisms and autophagy regulation. Using high-throughput proteomics and transcriptomic analyses, key proteins and signaling pathways were identified. BTG1 emerged as a signature gene, while autophagy-related genes such as BECN1, ATG5, HSPA8, PTEN, and MAPK8 were highlighted as pivotal players. In vitro experiments using Rituximab-sensitive and -resistant DLBCL cell lines (Raji and Raji-4RH) demonstrated that Chidamide significantly inhibited cell proliferation in a dose- and time-dependent manner, induced G0/G1 phase arrest, and enhanced autophagy. Mechanistically, Chidamide upregulated histone acetylation and autophagy-related proteins while reducing p62 levels, synergistically promoting autophagy with Rituximab. In vivo mouse models confirmed the combined treatment's efficacy in suppressing tumor growth. These findings suggest that the BTG1/BECN1/ATG5 signaling axis plays a critical role in enhancing autophagy and reversing Rituximab resistance. The combination of Chidamide and Rituximab presents a promising therapeutic strategy, offering new insights into overcoming drug resistance in DLBCL.

HDAC inhibitors: Cardiotoxicity and paradoxical cardioprotective effect in ischemia-reperfusion myocardiocyte injury

Histone deacetylase inhibitors (HDACIs) are epigenetic drugs that regulate the acetylation status of histones and non-histone proteins, thereby leading to chromatin remodeling and transcriptional regulation of key apoptotic and cell cycle regulatory genes. There are currently five HDACIs clinically approved by the major regulatory authorities for treating hematological cancers, primarily as monotherapy. While HDACIs have been particularly effective in T-cell lymphomas, their clinical efficacies have not yet extended to solid tumors. The development of HDACIs continues, including for the treatment of a non-malignant conditions, with givinostat recently approved by the US FDA. However, the early development of HDACIs was limited by concerns about cardiotoxicity including QT interval prolongation. Yet, paradoxically, the latest research suggests some cardioprotective effect of HDACIs in ischemic heart disease or heart failure. This review presents the latest update about the cardiotoxicity of the clinically approved HDACIs. The mechanisms leading to HDACI-induced cardiotoxic adverse events and clinical strategies for their management are discussed. We will also deliberate the potential repurposing use of HDACIs and their HDAC isoform selectivity for treating ischemia-reperfusion cardiac muscle injury, cardiac hypertrophy, and fibrosis.

Tumor-Associated Macrophages as Key Modulators of Disease Progression in Diffuse Large B-Cell Lymphoma

With the advent of new therapeutic approaches, there is hope that anticancer treatment will eventually be possible without the use of chemotherapy. Efficient immunotherapeutic options have recently emerged in many cancers, offering a less aggressive approach, with overall better tolerance, making them also suitable for frail patients. Response to immunotherapy relies on the availability, functionality, and efficacy of the host's immune effector mechanisms. One of the key factors determining the efficacy of immunotherapy is the tumor microenvironment, which encompasses various immune effectors, including macrophages, which play a crucial role in regulating immune responses through phagocytosis and antigen presentation. Macrophages are prototypically divided, according to their polarization, into either the pro-inflammatory M1 type or the anti-inflammatory M2 type. In the tumor microenvironment, M2-polarized macrophages, known as tumor-associated macrophages (TAMs), are the predominant phenotype and are associated with tumor progression. The M1/M2 paradigm contributes to the understanding of tumor progression. Due to the variable microenvironment, the mechanisms regulating TAMs can vary across different cancers. Variations in TAM polarization may account for the different treatment responses in patients with similar diseases. This paper investigates the connection between TAMs, disease progression, and treatment responses in the most frequent solid hematologic cancer, diffuse large B-cell lymphoma.

Chidamide, a Histone Deacetylase Inhibitor, Combined With R-GemOx in Relapsed/Refractory Diffuse Large B-Cell Lymphoma (TRUST): A Multicenter, Single-Arm, Phase 2 Trial

BACKGROUND

Histone deacetylase (HDAC) inhibitors demonstrated a synergistic anti-tumor effect with rituximab and chemotherapy in preclinical studies on diffuse large B-cell lymphoma (DLBCL). This phase 2 trial aimed to evaluate the efficacy and safety of chidamide, an orally active HDAC inhibitor, plus the R-GemOx regimen for relapsed/refractory (R/R) DLBCL.

METHODS

Patients with transplantation-ineligible R/R DLBCL received chidamide (20 mg, oral, days 1, 4, 8, 11, 15, and 18), rituximab (375 mg/m2, day 1), gemcitabine (1000 mg/m2, day 2), and oxaliplatin (100 mg/m2, day 2) in a 21-day cycle for 6 cycles (induction phase), followed by chidamide (20 mg, oral, twice weekly on Mondays and Thursdays) until disease progression or intolerable toxicity (maintenance phase). The primary endpoint was overall response rate (ORR).

RESULTS

Between June 19, 2019 and July 5, 2022, 54 patients were enrolled. The ORR was 59.3% (95% CI: 45.0-72.4). With a median follow-up of 38.1 months (interquartile range: 19.5-48.2), the median progression-free survival and overall survival were 7.4 (95% CI: 5.2-14.2) and 23.9 (95% CI: 15.2-not reached) months, respectively. The most common grade 3/4 treatment-emergent adverse events (TEAEs) were neutropenia (40.7%), thrombocytopenia (33.3%), and leukopenia (27.8%). Whole-exome sequencing showed that CREBBP mutations and BTG2 mutations were associated with poor response and survival.

CONCLUSION

Chidamide plus R-GemOx demonstrated promising anti-tumor activity with acceptable toxicities in transplantation-ineligible R/R DLBCL patients. Patients with CREBBP mutations and BTG2 mutations had inferior response and survival.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04022005.

Mechanisms of HDACs in cancer development

Histone deacetylases (HDACs) are a class of epigenetic regulators that play pivotal roles in key biological processes such as cell proliferation, differentiation, metabolism, and immune regulation. Based on this, HDAC inhibitors (HDACis), as novel epigenetic-targeted therapeutic agents, have demonstrated significant antitumor potential by inducing cell cycle arrest, activating apoptosis, and modulating the immune microenvironment. Current research is focused on developing highly selective HDAC isoform inhibitors and combination therapy strategies tailored to molecular subtypes, aiming to overcome off-target effects and resistance issues associated with traditional broad-spectrum inhibitors. This review systematically elaborates on the multidimensional regulatory networks of HDACs in tumor malignancy and assesses the clinical translation progress of next-generation HDACis and their prospects in precision medicine, providing a theoretical framework and strategic reference for the development of epigenetic-targeted antitumor drugs.

Epigenetic Symphony in Diffuse Large B-Cell Lymphoma: Orchestrating the Tumor Microenvironment

DLBCL is a testament to the complexity of nature. It is characterized by remarkable diversity in its molecular and pathological subtypes and clinical manifestations. Despite the strides made in DLBCL treatment and the introduction of innovative drugs, around one-third of patients face a relapse or develop refractory disease. Recent findings over the past ten years have highlighted the critical interplay between the evolution of DLBCL and various epigenetic mechanisms, including chromatin remodeling, DNA methylation, histone modifications, and the regulatory roles of non-coding RNAs. These epigenetic alterations are integral to the pathways of oncogenesis, tumor progression, and the development of therapeutic resistance. In the past decade, the identification of dysregulated epigenetic mechanisms in lymphomas has paved the way for an exciting field of epigenetic therapies. Crucially, these epigenetic transformations span beyond tumor cells to include the sophisticated network within the tumor microenvironment (TME). While the exploration of epigenetic dysregulation in lymphoma cells is thriving, the mechanisms affecting the functions of immune cells in the TME invite further investigation. This review is dedicated to weaving together the narrative of epigenetic alterations impacting both lymphoma cells with a focus on their infiltrating immune companions.

In the era of targeted therapy and immunotherapy: advances in the treatment of large B-cell lymphoma of immune-privileged sites

Primary large B-cell lymphomas of immune-privileged sites (IP-LBCLs) include primary central nervous system large B-cell lymphoma (PCNSL), primary vitreoretinal large B-cell lymphoma (PVRL), and primary testicular large B-cell lymphoma (PTL). These tumors not only have a unique anatomical distribution but also exhibit specific biological and clinical characteristics. Given the high biological overlap between intravascular large B-cell lymphoma (IVLBCL) and IP-LBCLs, and the fact that IVLBCL is confined to the intravascular microenvironment, IVLBCL is currently included in the category of IP-LBCLs. IP-LBCLs are associated with suboptimal prognosis. However, advancements in biomarker detection technologies have facilitated novel therapeutic approaches for this disease entity. This review aims to summarize and analyze the latest research progress in IP-LBCLs, with a focus on new treatment strategies in the era of targeted therapy and immunotherapy. It is intended to further understand the biological characteristics, treatment, and latest advancements of this disease.

The current landscape of frontline large B-cell lymphoma trials

ABSTRACT

At least 25% to 35% of patients with large B-cell lymphoma (LBCL) are not cured with frontline treatment, with generally poor subsequent outcomes. This motivates ongoing and intense interest in improving the frontline treatment of this disease. R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) has remained the standard of care for 20 years despite dozens of trials aiming to improve upon this regimen, and only recently has a novel regimen (pola-R-CHP [polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisone]) challenged its supremacy. Fortunately, at least 15 promising randomized trials evaluating new treatments in frontline LBCL treatment are underway. They differ not only in the therapy evaluated in the experimental arm, but in the choice of control arm, primary end point, and patient selection strategy, with some targeting specific biologic subtypes, some focusing on specific high-risk patient populations, and others enrolling older or frail patients. Novel response-adapted strategies leveraging circulating tumor DNA are also underway. Although this variety of approaches provides a welcome increase in the overall likelihood of success, it will also present challenges if several of these trials are successful and we must choose among multiple potential treatment options that were not all tested in the same fashion. In this review, we summarize the main ongoing frontline randomized trials and discuss some of the questions that we will face in interpreting and applying their results in clinical practice in the next few years.

Advances in epigenetic therapies for B-cell non-hodgkin lymphoma

B-cell non-Hodgkin lymphomas (B-NHLs) constitute a varied group of cancers originating from B lymphocytes. B-NHLs can occur at any stage of normal B-cell development, with most arising from germinal centres (e.g. diffuse large B-cell lymphoma, DLBCL and follicular lymphoma, FL). The standard initial treatment usually involves the chemoimmunotherapy regimen. Although there is a high initial response rate, 30-40% of high-risk patients often face relapsed or refractory lymphoma due to drug resistance. Recent research has uncovered a significant link between the development of B-NHLs and various epigenetic processes, such as DNA methylation, histone modification, regulation by non-coding RNAs, and chromatin remodeling. Therapies targeting these epigenetic changes have demonstrated considerable potential in clinical studies. This article examines the influence of epigenetic regulation on the onset and progression of B-NHLs. It discusses the current therapeutic targets and agents linked to these epigenetic mechanisms, with the goal of offering new perspectives and approaches for targeted therapies and combination chemotherapy in treating B-NHLs.

Epigenetics-targeted drugs: current paradigms and future challenges

Epigenetics governs a chromatin state regulatory system through five key mechanisms: DNA modification, histone modification, RNA modification, chromatin remodeling, and non-coding RNA regulation. These mechanisms and their associated enzymes convey genetic information independently of DNA base sequences, playing essential roles in organismal development and homeostasis. Conversely, disruptions in epigenetic landscapes critically influence the pathogenesis of various human diseases. This understanding has laid a robust theoretical groundwork for developing drugs that target epigenetics-modifying enzymes in pathological conditions. Over the past two decades, a growing array of small molecule drugs targeting epigenetic enzymes such as DNA methyltransferase, histone deacetylase, isocitrate dehydrogenase, and enhancer of zeste homolog 2, have been thoroughly investigated and implemented as therapeutic options, particularly in oncology. Additionally, numerous epigenetics-targeted drugs are undergoing clinical trials, offering promising prospects for clinical benefits. This review delineates the roles of epigenetics in physiological and pathological contexts and underscores pioneering studies on the discovery and clinical implementation of epigenetics-targeted drugs. These include inhibitors, agonists, degraders, and multitarget agents, aiming to identify practical challenges and promising avenues for future research. Ultimately, this review aims to deepen the understanding of epigenetics-oriented therapeutic strategies and their further application in clinical settings.

Real-world efficacy of chidamide plus R-CHOP in newly diagnosed double-expressor diffuse large B-cell lymphoma

Background

Approximately 20%-30% of diffuse large B-cell lymphoma (DLBCL) cases are classified as double-expressor lymphoma (DEL), characterized by the co-expression of the MYC and BCL2 proteins. However, the most effective therapeutic strategy for DEL remains unidentified.

Objectives

To evaluate the efficacy of a novel histone deacetylase inhibitor, chidamide, in combination with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (CR-CHOP) in the treatment of DEL.

Design

This was a retrospective study.

Methods

This study included 62 DEL patients from December 2016 to December 2020. All patients were administered a first-line treatment with CR-CHOP. The short-term efficacy, survival status, and adverse reactions in this population were observed, and the prognostic factors were analyzed.

Results

The median age was 53.9 years (range, 19-77). All patients received a median of six cycles (range, 1-8) of treatment, with 79.0% achieving complete response (CR) and an overall response rate of 88.7%. With a median follow-up of 45.5 months (range, 1-82), the median progression-free survival (PFS) and median overall survival (OS) had not yet been reached. However, the 3-year PFS rate was 71% (95% CI: 61-83), the 3-year OS rate was 87% (95% CI: 79-96), the 5-year PFS rate was 67% (95% CI: 55-80), and the 5-year OS rate was 85% (95% CI: 77-95). Age and autologous stem cell transplantation after CR or partial response were independent prognostic factors for PFS, while various clinical factors were not associated with OS outcomes. The most common grades 3-4 hematologic and nonhematologic toxicity were leukopenia (46.7%) and infection (21%), respectively.

Conclusion

This long-term follow-up study indicates that CR-CHOP in untreated DLBCL with the DEL phenotype demonstrates high short-term efficacy and safety as well as promising survival outcomes.

Tumor Biology Hides Novel Therapeutic Approaches to Diffuse Large B-Cell Lymphoma: A Narrative Review

Diffuse large B-cell lymphoma (DLBCL) is a malignancy of immense biological and clinical heterogeneity. Based on the transcriptomic or genomic approach, several different classification schemes have evolved over the years to subdivide DLBCL into clinically (prognostically) relevant subsets, but each leaves unclassified samples. Herein, we outline the DLBCL tumor biology behind the actual and potential drug targets and address the challenges and drawbacks coupled with their (potential) use. Therapeutic modalities are discussed, including small-molecule inhibitors, naked antibodies, antibody-drug conjugates, chimeric antigen receptors, bispecific antibodies and T-cell engagers, and immune checkpoint inhibitors. Candidate drugs explored in ongoing clinical trials are coupled with diverse toxicity issues and refractoriness to drugs. According to the literature on DLBCL, the promise for new therapeutic targets lies in epigenetic alterations, B-cell receptor and NF-κB pathways. Herein, we present putative targets hiding in lipid pathways, ferroptosis, and the gut microbiome that could be used in addition to immuno-chemotherapy to improve the general health status of DLBCL patients, thus increasing the chance of being cured. It may be time to devote more effort to exploring DLBCL metabolism to discover novel druggable targets. We also performed a bibliometric and knowledge-map analysis of the literature on DLBCL published from 2014-2023.

Targeted agents plus CHOP compared with CHOP as the first-line treatment for newly diagnosed patients with peripheral T-cell lymphoma (GUIDANCE-03): an open-label, multicentre phase 2 clinical trial

Background

Peripheral T-cell lymphoma (PTCL) is a heterogeneous disease with dismal outcomes. We conducted an open-label, phase 2 nonrandomised, externally controlled study to evaluate the efficacy and safety of targeted agents plus CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) (CHOPX) for PTCL in the front-line setting.

Methods

Eligible patients were ≥18 years of age and newly diagnosed PTCL. Patients in the CHOPX group received standard CHOP at Cycle 1. Specific targeted agents were added from Cycle 2, decitabine if TP53 mut, azacytidine if TET2/KMT2D mut, tucidinostat if CREBBP/EP300 mut, and lenalidomide if without mutations above. Patients in the CHOP group received CHOP for 6 cycles. The primary endpoint was the complete response rate (CRR) at the end of treatment (EOT). Secondary endpoints included overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety. The study was registered with ClinicalTrials.gov, NCT04480099.

Findings

Between July 29, 2020, and Sep 22, 2022, 96 patients were enrolled and included for efficacy and safety analysis with 48 in each group. The study met its primary endpoint. CRR at EOT in the CHOPX group was superior to the CHOP group (64.6% vs. 33.3%, OR 0.27, 95%CI 0.12-0.64; p = 0.004). At a median follow-up of 24.3 months (IQR 12.0-26.7), improved median PFS was observed in the CHOPX group (25.5 vs. 9.0 months; HR 0.57, 95%CI 0.34-0.98; p = 0.041). The median OS was similar between two groups (not reached vs. 30.9 months; HR 0.55, 95%CI 0.28-1.10; p = 0.088). The most common grade 3-4 hematological and non-hematological adverse events in the CHOPX group were neutropenia (31, 65%) and infection (5, 10%).

Interpretation

Targeted agents combined with CHOP demonstrated effective and safe as first-line treatment in PTCL. Biomarker-driven therapeutic strategy is feasible and may lead to promising efficacy specifically toward molecular features in PTCL.

Funding

This study was supported by the National Key Research and Development Program (2022YFC2502600) and the General Program of the Shanghai Municipal Health Commission (202040400).

Chidamide enhances T-cell-mediated anti-tumor immune function by inhibiting NOTCH1/NFATC1 signaling pathway in ABC-type diffuse large B-cell lymphoma

Chidamide (CS055/HBI-8000, tucidinostat) has shown promising effects in the clinical treatment of various hematologic tumors. Diffuse large B-cell lymphoma (DLBCL) has shown highly heterogeneous biological characteristics. There are complex mechanisms of the role of chidamide in DLBCL for in-depth study. It is essential to probe further into the mechanism of drug-tumor interactions as a guide to clinical application and to understand the occurrence and progression of DLBCL. In vitro and in vivo models were utilized to determine the effects of chidamide on signaling pathways involved in the DLBCL tumor microenvironment. The experimental results show that chidamide inhibited the proliferation of DLBCL cell lines in a dose- and time-dependent manner, and down-regulated the expression of NOTCH1 and NFATC1 in DLBCL cells as well as decreased the concentration of IL-10 in the supernatant. In addition, chidamide significantly lowered the expression of PD1 or TIM3 on CD4+T cells and CD8+T cells and elevated the levels of IL-2, IFN-γ, and TNF-α in the serum of animal models, which augmented the function of circulating T cells and tumor-infiltrating T cells and ultimately significantly repressed the growth of tumors. These findings prove that chidamide can effectively inhibit the cell activity of DLBCL cell lines by inhibiting the activation of NOTCH1 and NFATC1 signaling pathways. It can also improve the abnormal DLBCL microenvironment in which immune escape occurs, and inhibit immune escape. This study provides a new therapeutic idea for the exploration of individualized precision therapy for patients with malignant lymphoma.

Chidamide represses MYC expression and might improve survival for patients with double expressor lymphoma

Double expressor lymphoma (DEL), characterized by high expressions of both MYC and BCL-2, displays poor prognosis after current therapies. The HDAC inhibitor chidamide has been approved for treatment of T cell lymphoma, but its efficacy on B cell lymphoma is unclear. Here, by combining inhibition screening and transcriptomic analyses, we found that the sensitivity of B lymphoma cells to chidamide was positively correlated with the expression levels of MYC. Chidamide treatment reduced MYC protein levels and repressed MYC pathway in B lymphoma cells with high MYC expressions. Ectopic expression of MYC in chidamide-insensitive B lymphoma cells increased their response to chidamide. Thus, we proposed that adding chidamide into R-CHOP (CR-CHOP) might be effective for DEL, and retrospectively analyzed 185 DEL patients treated in West China Hospital. 80% of patients showed response to CR-CHOP treatment. In the median follow-up of 42 months, CR-CHOP significantly improve the survival for DEL patients with R-IPI ≤2. Totally 35 patients underwent autologous stem cell transplantation (ASCT) in remission and demonstrated a trend for better survival. Combining CR-CHOP with ASCT resulted in the most superior PFS and OS above all. For response patients, CR-CHOP reduced relapse with better PFS than R-CHOP-like regimens with or without ASCT. Taken together, our data indicated that chidamide repressed the MYC pathway in B lymphoma and is potentially efficacious to treat DEL.

Chidamide and orelabrutinib synergistically induce cell cycle arrest and apoptosis in diffuse large B-cell lymphoma by regulating the PI3K/AKT/mTOR pathway

OBJECTIVE

The initial therapeutic approach for diffuse large B-cell lymphoma (DLBCL) entails a rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) regimen. However, 40% of patients exhibit suboptimal responses, with some experiencing relapse and refractory conditions. This study aimed to explore novel therapeutic strategies and elucidate their underlying mechanisms in DLBCL.

METHODS

Bioinformatics techniques were employed to scrutinize correlations between the HDAC1, HDAC2, HDAC3, HDAC10, BTK, MYC, TP53, and BCL2 genes in DLBCL. In vitro experiments were conducted using DB and SU-DHL-4 cells treated with chidamide, orelabrutinib, and a combination of both. Cell viability was assessed by cell counting kit-8. Cell apoptosis and the cell cycle were determined using flow cytometry. Reactive oxygen species (ROS) production and mitochondrial function were assessed through ROS and JC-1 staining. RNA sequencing and western blot analyses were conducted to elucidate the molecular mechanisms underlying the combined action of chidamide and orelabrutinib in DLBCL cells.

RESULTS

This investigation revealed markedly enhanced antiproliferative effects when chidamide was combined with orelabrutinib. Compusyn software analysis indicated a synergistic effect of chidamide and orelabrutinib in inhibiting DLBCL cell proliferation, with a combination index (CI) < 1. This synergy further manifested as augmented cell cycle arrest, apoptosis induction, the downregulation of cell cycle-associated and antiapoptotic proteins, and the upregulation of proapoptotic proteins. Furthermore, the western blot and RNA-Seq findings suggested that combining chidamide and orelabrutinib modulated the PI3K/AKT/mTOR signaling pathway, thereby promoting DLBCL cell cycle arrest and apoptosis.

CONCLUSION

The findings of this study provide a compelling justification for the clinical utilization of chidamide and orelabrutinib to treat relapsed/refractory DLBCL.

Genetic subtype-guided immunochemotherapy in diffuse large B cell lymphoma: The randomized GUIDANCE-01 trial

We report the results of GUIDANCE-01 (NCT04025593), a randomized, phase II trial of R-CHOP alone or combined with targeted agents (R-CHOP-X) guided by genetic subtyping of newly diagnosed, intermediate-risk, or high-risk diffuse large B cell lymphoma (DLBCL). A total of 128 patients were randomized 1:1 to receive R-CHOP-X or R-CHOP. The study achieved the primary endpoint, showing significantly higher complete response rate with R-CHOP-X than R-CHOP (88% vs. 66%, p = 0.003), with overall response rate of 92% vs. 73% (p = 0.005). Two-year progression-free survival rates were 88% vs. 63% (p < 0.001), and 2-year overall survival rates were 94% vs. 77% (p = 0.001). Meanwhile, post hoc RNA-sequencing validated our simplified genetic subtyping algorithm and previously established lymphoma microenvironment subtypes. Our findings highlight the efficacy and safety of R-CHOP-X, a mechanism-based tailored therapy, which dually targeted genetic and microenvironmental alterations in patients with newly diagnosed DLBCL.

The role of chidamide in the treatment of B-cell non-Hodgkin lymphoma: An updated systematic review

B-cell non-Hodgkin lymphoma (B-NHL) is a lymphoid malignancy derived from B-cells that remains difficult to treat. Moreover, relapses and refractory cases are common. Abnormalities in epigenetic mechanisms, such as imbalanced histone acetylation affecting certain genes, contribute to relapses and refractory cases. Chidamide (tucidinostat) is a novel histone deacetylase inhibitor that can reverse this epigenetic imbalance and has been approved for the treatment of T-cell malignancies. However, the use of chidamide for B-NHL remains limited, and the lack of relevant literature exacerbates this limitation. We conducted this review to summarize the anticancer activity of chidamide against B-NHL and its clinical applications to overcome drug resistance. This systematic review was conducted according to the PRISMA 2020 guidelines, using some keyword combinations from MEDLINE and EBSCO. The inclusion and exclusion criteria were also defined. Of the 131 records retrieved from databases, 16 were included in the review. Nine articles revealed that chidamide limited tumor progression by modifying the tumor microenvironment, stopping the cell cycle, inducing apoptosis and autophagy, and enhancing complement-dependent and antibody-dependent cell-mediated cytotoxicities.According to seven other studies, administering chidamide in combination with another existing therapeutic regimen may benefit not only patients with relapsed/refractory B-NHL, but also those with newly diagnosed B-NHL. Chidamide plays many important roles in limiting B-NHL progression through epigenetic modifications. Thus, combining chidamide with other anticancer drugs may be more beneficial for patients with newly diagnosed and relapsed/refractory B-NHL.

Chem-map profiles drug binding to chromatin in cells

Characterizing drug-target engagement is essential to understand how small molecules influence cellular functions. Here we present Chem-map for in situ mapping of small molecules that interact with DNA or chromatin-associated proteins, utilizing small-molecule-directed transposase Tn5 tagmentation. We demonstrate Chem-map for three distinct drug-binding modalities as follows: molecules that target a chromatin protein, a DNA secondary structure or that intercalate in DNA. We map the BET bromodomain protein-binding inhibitor JQ1 and provide interaction maps for DNA G-quadruplex structure-binding molecules PDS and PhenDC3. Moreover, we determine the binding sites of the widely used anticancer drug doxorubicin in human leukemia cells; using the Chem-map of doxorubicin in cells exposed to the histone deacetylase inhibitor tucidinostat reveals the potential clinical advantages of this combination therapy. In situ mapping with Chem-map of small-molecule interactions with DNA and chromatin proteins provides insights that will enhance understanding of genome and chromatin function and therapeutic interventions.

Recent advancement of HDAC inhibitors against breast cancer

Recent studies highlight the great potential impact of HDAC inhibitors (HDACis) in suppressing TNBC, even though clinical trials including a single HDACis demonstrated unsatisfactory outcomes against TNBC. New compounds created to achieve isoform selectivity and/or a polypharmacological HDAC strategy have also produced interesting results. The current study discusses the HDACis pharmacophoric models and the structural alterations that produced drugs with strong inhibitory effects on TNBC progression. With more than 2 million new cases reported in 2018, breast cancer-the most common cancer among women worldwide-poses a significant financial burden on an already deteriorating public health system. Due to a lack of therapies being developed for triple-negative breast cancers and the development of resistance to the current treatment options, it is imperative to plan novel therapeutics in order to bring new medications to the pipeline. Additionally, HDACs deacetylate a large number of nonhistone cellular substrates that control a variety of biological processes, such as the beginning and development of cancer. The significance of HDACs in cancer and the therapeutic potential of HDAC inhibitor. Furthermore, we also reported molecular docking study with four HDAC inhibitors and performed molecular dynamic stimulation of the best dock score compound. Among the four ligands belinostat compound showed best binding affinity with histone deacetylase protein which was -8.7 kJ/mol. It also formed five conventional hydrogen bond with Gly 841, His 669, His 670, pro 809, and His 709 amino acid residues.

Targeting MYC-driven lymphoma: lessons learned and future directions

MYC plays a central role in tumorigenesis by orchestrating cell proliferation, growth and survival, among other transformation mechanisms. In particular, MYC has often been associated with lymphomagenesis. In fact, MYC overexpressing lymphomas such as high-grade B-cell lymphoma (HGBL) and double expressor diffuse large B-cell lymphomas (DLBCL), are considered addicted to MYC. In such a context, MYC targeting therapies are of special interest, as MYC withdrawal is expected to result in tumor regression. However, whether high MYC levels are always predictive of increased sensitivity to these approaches is not clear yet. Even though no MYC inhibitor has received regulatory approval to date, substantial efforts have been made to investigate avenues to render MYC a druggable target. Here, we summarize the different classes of molecules currently under development, which mostly target MYC indirectly in aggressive B-cell lymphomas, paying special attention to subtypes with MYC/BCL2 or BCL6 translocations or overexpression.

Epigenetic regulation in hematopoiesis and its implications in the targeted therapy of hematologic malignancies

Hematologic malignancies are one of the most common cancers, and the incidence has been rising in recent decades. The clinical and molecular features of hematologic malignancies are highly heterogenous, and some hematologic malignancies are incurable, challenging the treatment, and prognosis of the patients. However, hematopoiesis and oncogenesis of hematologic malignancies are profoundly affected by epigenetic regulation. Studies have found that methylation-related mutations, abnormal methylation profiles of DNA, and abnormal histone deacetylase expression are recurrent in leukemia and lymphoma. Furthermore, the hypomethylating agents and histone deacetylase inhibitors are effective to treat acute myeloid leukemia and T-cell lymphomas, indicating that epigenetic regulation is indispensable to hematologic oncogenesis. Epigenetic regulation mainly includes DNA modifications, histone modifications, and noncoding RNA-mediated targeting, and regulates various DNA-based processes. This review presents the role of writers, readers, and erasers of DNA methylation and histone methylation, and acetylation in hematologic malignancies. In addition, this review provides the influence of microRNAs and long noncoding RNAs on hematologic malignancies. Furthermore, the implication of epigenetic regulation in targeted treatment is discussed. This review comprehensively presents the change and function of each epigenetic regulator in normal and oncogenic hematopoiesis and provides innovative epigenetic-targeted treatment in clinical practice.

The Role of CREBBP/EP300 and Its Therapeutic Implications in Hematological Malignancies

Disordered histone acetylation has emerged as a key mechanism in promoting hematological malignancies. CREB-binding protein (CREBBP) and E1A-binding protein P300 (EP300) are two key acetyltransferases and transcriptional cofactors that regulate gene expression by regulating the acetylation levels of histone proteins and non-histone proteins. CREBBP/EP300 dysregulation and CREBBP/EP300-containing complexes are critical for the initiation, progression, and chemoresistance of hematological malignancies. CREBBP/EP300 also participate in tumor immune responses by regulating the differentiation and function of multiple immune cells. Currently, CREBBP/EP300 are attractive targets for drug development and are increasingly used as favorable tools in preclinical studies of hematological malignancies. In this review, we summarize the role of CREBBP/EP300 in normal hematopoiesis and highlight the pathogenic mechanisms of CREBBP/EP300 in hematological malignancies. Moreover, the research basis and potential future therapeutic implications of related inhibitors were also discussed from several aspects. This review represents an in-depth insight into the physiological and pathological significance of CREBBP/EP300 in hematology.

Case report: Successful management of a refractory double-expressor diffuse large B-cell lymphoma patient under the guidance of in vitro high-throughput drug sensitivity test

Introduction

Double-expressor diffuse large B-cell lymphoma (DEL), harboring double expression of MYC and BCL2, has an inferior prognosis following standard first-line therapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP). We initiated a clinical trial to treat newly diagnosed DEL with R-CHOP plus Bruton's tyrosine kinase (BTK) inhibitor (BTKi) zanubrutinib (ZR-CHOP) and achieved a high complete response (CR) rate while four patients progressed during therapy, one of them carrying ATM and CD58 mutations. We applied an in vitro high-throughput drug sensitivity test for the prediction of clinical responses to different drugs in this patient.

Case presentation

We report a 30-year-old female patient diagnosed with stage III (DEL), with ATM and CD58 mutations. The patient achieved partial response (PR) after two cycles of ZR-CHOP and remained PR after four cycles of ZR-CHOP, while the disease progressed after six cycles of ZR-CHOP. High-throughput drug screening using a panel of 117 compounds identified a range of therapies with efficacy for this patient. The primary tumor cells showed moderate sensitivity to bortezomib, thalidomide, and gemcitabine as a single agent and bortezomib, thalidomide, and dexamethasone (VTD) as a combined regimen. The patient was treated with two cycles of VTD regimen (bortezomib 1.3 mg/m², d1, 4, 8, 11; thalidomide 100 mg, d1-21; dexamethasone 20 mg, d1, 2, 4, 5, 8, 9) and achieved PR with only a small lesion left. Another two cycles of VTD plus gemcitabine were then administered, and the patient achieved CR. Stem cells were mobilized, and autologous hematopoietic stem cell transplantation was carried out afterward. The patient remained CR for more than 3 months after transplantation.

Conclusion

In this article, we present a first-line chemoresistant DEL patient with ATM and CD58 mutations who was treated successfully with VTD plus gemcitabine under the guidance of in vitro high-throughput drug sensitivity test.

Targeting Class I Histone Deacetylases in Human Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is the most frequent subtype of uterine sarcoma that presents a poor prognosis, high rates of recurrence, and metastasis. Currently, the molecular mechanism of the origin and development of uLMS is unknown. Class I histone deacetylases (including HDAC1, 2, 3, and 8) are one of the major classes of the HDAC family and catalyze the removal of acetyl groups from lysine residues in histones and cellular proteins. Class I HDACs exhibit distinct cellular and subcellular expression patterns and are involved in many biological processes and diseases through diverse signaling pathways. However, the link between class I HDACs and uLMS is still being determined. In this study, we assessed the expression panel of Class I HDACs in uLMS and characterized the role and mechanism of class I HDACs in the pathogenesis of uLMS. Immunohistochemistry analysis revealed that HDAC1, 2, and 3 are aberrantly upregulated in uLMS tissues compared to adjacent myometrium. Immunoblot analysis demonstrated that the expression levels of HDAC 1, 2, and 3 exhibited a graded increase from normal and benign to malignant uterine tumor cells. Furthermore, inhibition of HDACs with Class I HDACs inhibitor (Tucidinostat) decreased the uLMS proliferation in a dose-dependent manner. Notably, gene set enrichment analysis of differentially expressed genes (DEGs) revealed that inhibition of HDACs with Tucidinostat altered several critical pathways. Moreover, multiple epigenetic analyses suggested that Tucidinostat may alter the transcriptome via reprogramming the oncogenic epigenome and inducing the changes in microRNA-target interaction in uLMS cells. In the parallel study, we also determined the effect of DL-sulforaphane on the uLMS. Our study demonstrated the relevance of class I HDACs proteins in the pathogenesis of malignant uLMS. Further understanding the role and mechanism of HDACs in uLMS may provide a promising and novel strategy for treating patients with this aggressive uterine cancer.

Chinese expert consensus on oral drugs for the treatment of mature B-cell lymphomas (2020 edition)

Oral drugs such as ibrutinib play an important role in the treatment of mature B-cell lymphoma (BCL) due to their reliable efficacy, manageable safety, high accessibility, and convenience for use. Still, no guidelines or consensus focusing on oral drug therapies for BCL is available. To provide a reference of oral agent-based treatment for mature BCL, a panel of experts from the Lymphocyte Disease Group, Chinese Society of Hematology, Chinese Medical Association conducted an extensive discussion and reached a consensus on oral drugs for Chinese BCL patients on the basis of the current application status of oral drugs in China, combined with the latest authoritative guidelines in the world and current research reports. This consensus reviewed the application of oral drugs in the treatment of BCL and the latest research and provided appropriate recommendations on the use of oral drugs for indolent or aggressive BCL patients. With the deepening of research and the development of standardized clinical applications, oral medications will bring better treatment to BCL patients, enabling more patients to benefit from them.

Therapeutic potential of tucidinostat, a subtype-selective HDAC inhibitor, in cancer treatment

Histone deacetylase (HDAC) is one of the most characterized epigenetic modifiers, modulating chromatin structure and gene expression, which plays an important role in cell cycle, differentiation and apoptosis. Dysregulation of HDAC promotes cancer progression, thus inhibitors targeting HDACs have evidently shown therapeutic efficacy in multiple cancers. Tucidinostat (formerly known as chidamide), a novel subtype-selective HDAC inhibitor, inhibits Class I HDAC1, HDAC2, HDAC3, as well as Class IIb HDAC10. Tucidinostat is approved in relapsed or refractory (R/R) peripheral T-cell lymphoma (PTCL), advanced breast cancer and R/R adult T-cell leukemia-lymphoma (ATLL). Compared with other HDAC inhibitors, tucidinostat shows notable antitumor activity, remarkable synergistic effect with immunotherapy, and manageable toxicity. Here, we comprehensively summarize recent advances in tucidinostat as both monotherapy and a regimen of combination therapy in both hematological and solid malignancies in clinic. Further studies will endeavor to identify more combination strategies with tucidinostat and to identify specific clinical biomarkers to predict the therapeutic effect.

HDAC Inhibitors for the Therapy of Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is an urgent as well as huge medical challenge, which is associated with poor prognosis and responsiveness to chemotherapies. Since epigenetic changes are highly implicated in TNBC tumorigenesis and development, inhibitors of histone deacetylases (HDACIs) could represent a promising therapeutic strategy. Although clinical trials involving single HDACIs showed disappointing results against TNBC, recent studies emphasize the high potential impact of HDACIs in controlling TNBC. In addition, encouraging results stem from new compounds designed to obtain isoform selectivity and/or polypharmacological HDAC approach. The present review provides a discussion of the HDACIs pharmacophoric models and of the structural modifications, leading to compounds with a potent activity against TNBC progression.

The Status and Prospects of Epigenetics in the Treatment of Lymphoma

The regulation of gene transcription by epigenetic modifications is closely related to many important life processes and is a hot research topic in the post-genomic era. Since the emergence of international epigenetic research in the 1990s, scientists have identified a variety of chromatin-modifying enzymes and recognition factors, and have systematically investigated their three-dimensional structures, substrate specificity, and mechanisms of enzyme activity regulation. Studies of the human tumor genome have revealed the close association of epigenetic factors with various malignancies, and we have focused more on mutations in epigenetically related regulatory enzymes and regulatory recognition factors in lymphomas. A number of studies have shown that epigenetic alterations are indeed widespread in the development and progression of lymphoma and understanding these mechanisms can help guide clinical efforts. In contrast to chemotherapy which induces cytotoxicity, epigenetic therapy has the potential to affect multiple cellular processes simultaneously, by reprogramming cells to achieve a therapeutic effect in lymphoma. Epigenetic monotherapy has shown promising results in previous clinical trials, and several epigenetic agents have been approved for use in the treatment of lymphoma. In addition, epigenetic therapies in combination with chemotherapy and/or immunotherapy have been used in various clinical trials. In this review, we present several important epigenetic modalities of regulation associated with lymphoma, summarize the corresponding epigenetic drugs in lymphoma, and look at the future of epigenetic therapies in lymphoma.

Preclinical Evaluation of the HDAC Inhibitor Chidamide in Transformed Follicular Lymphoma

The key factors leading to transformed follicular lymphoma (t-FL) include the aberrations of epigenetic modifiers as early and driving events, especially mutations in the gene encoding for histone acetyltransferase. Therefore, reversal of this phenomenon by histone deacetylase (HDAC) inhibitors is essential for the development of new treatment strategies in t-FL. Several t-FL cell lines were treated with various doses of chidamide and subjected to cell proliferation, apoptosis and cell cycle analyses with CCK-8 assay, Annexin V/PI assay and flow cytometry, respectively. Chidamide dose-dependently inhibited cell proliferation, caused G0/G1 cycle arrest and triggered apoptosis in t-FL cells. In addition, the effects of chidamide on tumor growth were evaluated in vivo in xenograft models. RNA-seq analysis revealed gene expression alterations involving the PI3K-AKT signaling pathway might account for the mechanism underlying the antitumor activity of chidamide as a single agent in t-FL. These findings provide a basis for further clinical exploration of chidamide as a promising treatment for FL.

HDAC Inhibitors: Dissecting Mechanisms of Action to Counter Tumor Heterogeneity

Intra-tumoral heterogeneity presents a major obstacle to cancer therapeutics, including conventional chemotherapy, immunotherapy, and targeted therapies. Stochastic events such as mutations, chromosomal aberrations, and epigenetic dysregulation, as well as micro-environmental selection pressures related to nutrient and oxygen availability, immune infiltration, and immunoediting processes can drive immense phenotypic variability in tumor cells. Here, we discuss how histone deacetylase inhibitors, a prominent class of epigenetic drugs, can be leveraged to counter tumor heterogeneity. We examine their effects on cellular processes that contribute to heterogeneity and provide insights on their mechanisms of action that could assist in the development of future therapeutic approaches.