Manipulating the epigenome in germinal center lymphomas: is it getting easier and ezier?

Targeting Monoallelic CREBBP / EP300 Mutations in Germinal Center-Derived B-Cell Lymphoma with a First-in-Class Histone Acetyltransferase Activator

Inactivating, monoallelic mutations in histone acetyltransferases (HATs) CREBBP / EP300 are common in germinal center (GC) B-cell lymphomas and are implicated in derangements of the GC reaction, evasion of immune surveillance, and disease initiation. This study evaluates a first-in-class HAT activator, YF2, as a way to allosterically induce the functional HAT allele. YF2 binds to the bromo/RING domains of CREBBP/p300, increasing enzyme auto-acetylation and activation, and is selectively cytotoxic in HAT-mutated lymphoma cell lines. YF2 induces CREBBP/p300-mediated acetylation of putative targets including H3K27, p53, and BCL6. Treatment with YF2 transcriptionally activates numerous immunological pathways and increases markers of antigen presentation. Furthermore, YF2 modulates the GC reaction and increases B-cell maturation. YF2 is well tolerated in vivo and improves survival in cell line- and patient-derived xenograft lymphoma mouse models. In summary, pharmacological activation of the functional HAT allele using YF2 effectively counteracts monoallelic CREBBP / EP300 mutations in GC B-cell lymphoma.

Putting the clinical and biological heterogeneity of non-hodgkin lymphoma into context

The lymphomas represent one of the most heterogeneous groups of malignancies in all of cancer medicine. Whether one attempts to understand these diseases in the context of their complicated ontogeny, unique biologic features, or clinical presentation, this heterogeneity has been a mixed blessing. On the one hand, it has created an ever-changing way to classify these diseases, as classification schemes have been compelled to reflect the rapidly emerging information that seems to split the disease into smaller and smaller subtypes. On the other hand, the biologic and clinical dissection of these diseases has allowed for the identification of unique biologic features-features that have led to novel targets and generated a plethora of new drugs. Virtually every subtype of non-Hodgkin lymphoma has benefited from these efforts to understand the biology of the different subtypes. This paradigm has led to new clinical trials that tailor novel drug regimens to specific biologic disease subtypes. As a prelude to this CCR Focus section, we attempt to put this evolving heterogeneity into context, bridging historical and modern-day views of classification of these diseases. Then, some of the world's leading lymphoma researchers share their perspectives on how to formulate new concepts of care in this era of biologic discovery. Over a relatively short time, the advances in lymphoma research have been nothing short of stunning. There now seems to be little doubt that these recent breakthroughs will redound favorably on the majority of patients diagnosed with a lymphoproliferative malignancy. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."