Zebularine-induced myeloma cell death is accompanied by decreased c-Myc expression

A drug-delivery depot for epigenetic modulation and enhanced cancer immunotherapy

DNA methyltransferase inhibitors (DNMTis) have found widespread application in the management of cancer. Zebularine (Zeb), functioning as a demethylating agent, has exhibited notable advantages and enhanced therapeutic efficacy in the realm of tumour immunotherapy. Nevertheless, due to its lack of targeted functionality, standalone Zeb therapy necessitates the administration of a substantially higher dosage. In this investigation, we have devised an innovative nanodrug formulation, comprising the DNA methyltransferase inhibitor Zeb and pH-responsive chitosan (CS), hereinafter referred to as CS-Zeb nanoparticles (NPs). Our findings have unveiled that CS-Zeb NPs manifest heightened drug release within an acidic milieu (pH 5.5) in comparison to a neutral environment (pH 7.4). Furthermore, in vivo studies have conclusively affirmed that, in contrast to equivalent quantities of Zeb in isolation, the nanocomplex significantly curtailed tumour burden and protracted the survival duration of the B16F10 tumour-bearing murine model. Additionally, CS-Zeb NPs elicited an augmentation of CD8+ T cells within the peripheral circulation of mice and tumour-infiltrating lymphocytes (TILs). Notably, the dosage of CS-Zeb NPs was reduced by a remarkable 70-fold when juxtaposed with Zeb administered in isolation. To summarise, our study underscores the potential of CS-Zeb NPs as an alternative chemotherapeutic agent for cancer treatment.

Aberrant DNA methylation in multiple myeloma: A major obstacle or an opportunity?

Drug resistance (DR) of cancer cells leading to relapse is a huge problem nowadays to achieve long-lasting cures for cancer patients. This also holds true for the incurable hematological malignancy multiple myeloma (MM), which is characterized by the accumulation of malignant plasma cells in the bone marrow (BM). Although new treatment approaches combining immunomodulatory drugs, corticosteroids, proteasome inhibitors, alkylating agents, and monoclonal antibodies have significantly improved median life expectancy, MM remains incurable due to the development of DR, with the underlying mechanisms remaining largely ill-defined. It is well-known that MM is a heterogeneous disease, encompassing both genetic and epigenetic aberrations. In normal circumstances, epigenetic modifications, including DNA methylation and posttranslational histone modifications, play an important role in proper chromatin structure and transcriptional regulation. However, in MM, numerous epigenetic defects or so-called ‘epimutations’ have been observed and this especially at the level of DNA methylation. These include genome-wide DNA hypomethylation, locus specific hypermethylation and somatic mutations, copy number variations and/or deregulated expression patterns in DNA methylation modifiers and regulators. The aberrant DNA methylation patterns lead to reduced gene expression of tumor suppressor genes, genomic instability, DR, disease progression, and high-risk disease. In addition, the frequency of somatic mutations in the DNA methylation modifiers seems increased in relapsed patients, again suggesting a role in DR and relapse. In this review, we discuss the recent advances in understanding the involvement of aberrant DNA methylation patterns and/or DNA methylation modifiers in MM development, progression, and relapse. In addition, we discuss their involvement in MM cell plasticity, driving myeloma cells to a cancer stem cell state characterized by a more immature and drug-resistant phenotype. Finally, we briefly touch upon the potential of DNA methyltransferase inhibitors to prevent relapse after treatment with the current standard of care agents and/or new, promising (immuno) therapies.

DNA Methylation of T Lymphocytes as a Therapeutic Target: Implications for Rheumatoid Arthritis Etiology

Rheumatoid arthritis (RA) is an autoimmune disease that can cause joint damage and disability. Epigenetic variation, especially DNA methylation, has been shown to be involved in almost all the stages of the pathology of RA, from autoantibody production to various self-effector T cells and the defects of protective T cells that can lead to chronic inflammation and erosion of bones and joints. Given the critical role of T cells in the pathology of RA, the regulatory functions of DNA methylation in T cell biology remain unclear. In this review, we elaborate on the relationship between RA pathogenesis and DNA methylation in the context of different T cell populations. We summarize the relevant methylation events in T cell development, differentiation, and T cell-related genes in disease prediction and drug efficacy. Understanding the epigenetic regulation of T cells has the potential to profoundly translate preclinical results into clinical practice and provide a framework for the development of novel, individualized RA therapeutics.

Decoding DNA methylation in epigenetics of multiple myeloma

Dysregulation of DNA methylation in B cells has been observed during their neoplastic transformation and therefore closely associated with various B-cell malignancies including multiple myeloma (MM), a malignancy of terminally differentiated plasma cells. Emerging evidence has unveiled pronounced alterations in DNA methylation in MM, including both global and gene-specific changes that can affect genome stability and gene transcription. Moreover, dysregulated expression of DNA methylation-modifying enzymes has been related with myelomagenesis, disease progression, and poor prognosis. However, the functional roles of the epigenetic abnormalities involving DNA methylation in MM remain elusive. In this article, we review current understanding of the alterations in DNA methylome and DNA methylation modifiers in MM, particularly focusing on DNA methyltransferases (DNMTs) and tet methylcytosine dioxygenases (TETs). We also discuss how these DNA methylation modifiers may be regulated and function in MM cells, therefore providing a rationale for developing novel epigenetic therapies targeting DNA methylation in MM.