NSD2 as a Promising Target in Hematological Disorders

NSD family proteins: Rising stars as therapeutic targets

Epigenetic modifications, including DNA methylation and histone post-translational modifications, intricately regulate gene expression patterns by influencing DNA accessibility and chromatin structure in higher organisms. These modifications are heritable, are independent of primary DNA sequences, undergo dynamic changes during development and differentiation, and are frequently disrupted in human diseases. The reversibility of epigenetic modifications makes them promising targets for therapeutic intervention and drugs targeting epigenetic regulators (e.g., tazemetostat, targeting the H3K27 methyltransferase EZH2) have been applied in clinical therapy for multiple cancers. The NSD family of H3K36 methyltransferase enzymes-including NSD1 (KMT3B), NSD2 (MMSET/WHSC1), and NSD3 (WHSC1L1)-are now receiving drug development attention, with the exciting advent of an NSD2 inhibitor (KTX-1001) advancing to Phase I clinical trials for relapsed or refractory multiple myeloma. NSD proteins recognize and catalyze methylation of histone lysine marks, thereby regulating chromatin integrity and gene expression. Multiple studies have implicated NSD proteins in human disease, noting impacts from translocations, aberrant expression, and various dysfunctional somatic mutations. Here, we review the biological functions of NSD proteins, epigenetic cooperation related to NSD proteins, and the accumulating evidence linking these proteins to developmental disorders and tumorigenesis, while additionally considering prospects for the development of innovative epigenetic therapies.

Myeloma and DNA damage

ABSTRACT

DNA-damaging agents have represented the first effective treatment for the blood cancer multiple myeloma, and after 65 years since their introduction to the clinic, they remain one of the mainstay therapies for this disease. Myeloma is a cancer of plasma cells. Despite exceedingly slow proliferation, myeloma cells present extended genomic rearrangements and intense genomic instability, starting at the premalignant stage of the disease. Where does such DNA damage stem from? A reliable model argues that the powerful oncogenes activated in myeloma as well the phenotypic peculiarities of cancer plasma cells, including the dependency on the proteasome for survival and the constant presence of oxidative stress, all converge on modulating DNA damage and repair. Beleaguered by these contraposing forces, myeloma cells survive in a precarious balance, in which the robust engagement of DNA repair mechanisms to guarantee cell survival is continuously challenged by rampant genomic instability, essential for cancer cells to withstand hostile selective pressures. Shattering this delicate equilibrium has been the goal of the extensive use of DNA-damaging agents since their introduction in the clinic, now enriched by novel approaches that leverage upon synthetic lethality paradigms. Exploiting the impairment of homologous recombination caused by myeloma genetic lesions or treatments, it is now possible to design therapeutic combinations that could target myeloma cells more effectively. Furthermore, DNA-damaging agents, as demonstrated in solid tumors, may sensitize cells to immune therapies. In all, targeting DNA damage and repair remains as central as ever in myeloma, even for the foreseeable future.

Drug Discovery Targeting Nuclear Receptor Binding SET Domain Protein 2 (NSD2)

Nuclear receptor binding SET domain proteins (NSDs) catalyze the mono- or dimethylation of histone 3 lysine 36 (H3K36me1 and H3K36me2), using S-adenosyl-l-methionine (SAM) as a methyl donor. As a key member of the NSD family of proteins, NSD2 plays an important role in the pathogenesis and progression of various diseases such as cancers, inflammations, and infectious diseases, serving as a promising drug target. Developing potent and specific NSD2 inhibitors may provide potential novel therapeutics. Several NSD2 inhibitors and degraders have been discovered while remaining in the early stage of drug development. Excitingly, KTX-1001, a selective NSD2 inhibitor, has entered clinical trials. In this Perspective, the structures and functions of NSD2, its roles in various human diseases, and the recent advances in drug discovery strategies targeting NSD2 have been summarized. The challenges, opportunities, and future directions for developing NSD2 inhibitors and degraders are also discussed.

Editorial: Special Issue "Stem Cell Biology and Cancer"

Cancer stem cells (CSCs) are now well-established as key players in tumor initiation, progression, and therapy resistance [...].

Targeted Epigenetic Interventions in Cancer with an Emphasis on Pediatric Malignancies

Over the past two decades, novel hallmarks of cancer have been described, including the altered epigenetic landscape of malignant diseases. In addition to the methylation and hyd-roxymethylation of DNA, numerous novel forms of histone modifications and nucleosome remodeling have been discovered, giving rise to a wide variety of targeted therapeutic interventions. DNA hypomethylating drugs, histone deacetylase inhibitors and agents targeting histone methylation machinery are of distinguished clinical significance. The major focus of this review is placed on targeted epigenetic interventions in the most common pediatric malignancies, including acute leukemias, brain and kidney tumors, neuroblastoma and soft tissue sarcomas. Upcoming novel challenges include specificity and potential undesirable side effects. Different epigenetic patterns of pediatric and adult cancers should be noted. Biological significance of epigenetic alterations highly depends on the tissue microenvironment and widespread interactions. An individualized treatment approach requires detailed genetic, epigenetic and metabolomic evaluation of cancer. Advances in molecular technologies and clinical translation may contribute to the development of novel pediatric anticancer treatment strategies, aiming for improved survival and better patient quality of life.