Synergistic anti-AML effects of the LSD1 inhibitor T-3775440 and the NEDD8-activating enzyme inhibitor pevonedistat via transdifferentiation and DNA rereplication

Lysine-specific demethylase 1A (LSD1, KDM1A) specifically demethylates di- and monomethylated histones H3K4 and K9, resulting in context-dependent transcriptional repression or activation. We previously identified an irreversible LSD1 inhibitor T-3775440, which exerts antileukemic activities in a subset of acute myeloid leukemia (AML) cell lines by inducing cell transdifferentiation. The NEDD8-activating enzyme inhibitor pevonedistat (MLN4924, TAK-924) is an investigational drug with antiproliferative activities in AML, and is also reported to induce cell differentiation. We therefore tested the combination of these two agents in AML models. The combination treatment resulted in synergistic growth inhibition of AML cells, accompanied by enhanced transdifferentiation of an erythroid leukemia lineage into granulomonocytic-like lineage cells. In addition, pevonedistat-induced rereplication stress during the S phase was greatly augmented by concomitant treatment with T-3775440, as reflected by the increased induction of apoptosis. We further demonstrated that the combination treatment was markedly effective in subcutaneous tumor xenograft models as well as in a disseminated model of AML, leading to tumor eradication or prolonged survival in T-3775440/pevonedistat cotreated mice. Our findings indicate the therapeutic potential of the combination of LSD1 inhibitors and pevonedistat for the treatment of AML.

Eosinophilic annular erythema is clinically characterized by central pigmentation reflecting basal melanosis: a clinicopathological study of 10 cases

BACKGROUND

Eosinophilic annular erythema (EAE) has been proposed as a clinical entity to describe annular skin lesions associated with tissue eosinophilia. However, systematic investigations on the histopathology of EAE have not been performed, and useful histopathological findings for diagnosis of EAE remain unknown.

OBJECTIVE

The aim of this study was to investigate the clinicopathological features of EAE.

METHODS

We retrospectively studied 10 patients at our hospital during a 5-year span who clinically showed annular or figurate lesions and histopathologically exhibited eosinophilic infiltration in the dermis.

RESULTS

Nine of the 10 cases had annular lesions with pigmentation on the interior side. Blood eosinophilia was found in only one patient. Histopathologically, basal melanosis was observed in nine cases. Infiltration of eosinophils was confined to the dermis in nine cases. Patients treated with systemic corticosteroid tended to show less recurrence than those treated with topical corticosteroid.

LIMITATIONS

The main limitation of our study is the small number of patients.

CONCLUSION

Skin biopsy should be performed when EAE is suspected, even in cases without blood eosinophilia. Basal melanosis and tissue eosinophilia confined to the dermis suggest the diagnosis of EAE. We recommend topical corticosteroids as the initial treatment for EAE.

Electron momentum densities near Dirac cones: Anisotropic Umklapp scattering and momentum broadening

The relationship between electron momentum densities (EMDs) and a band gap is clarified in momentum space. The interference between wavefunctions via reciprocal lattice vectors, making a band gap in momentum space, causes the scattering of electrons from the first Brillouin zone to the other zones, so-called Umklapp scattering. This leads to the broadening of EMDs. A sharp drop of the EMD in the limit of a zero gap becomes broadened as the gap opens. The broadening is given by a simple quantity, E_g/v_F, where E_g is the gap magnitude and v_F the Fermi velocity. As the ideal case to see such an effect, we investigate the EMDs in graphene and graphite. They are basically semimetals, and their EMDs have a hexagonal shape enclosed in the first Brillouin zone. Since the gap is zero at Dirac points, a sharp drop exists at the corners (K/K’ points) while the broadening becomes significant away from K/K’s, showing the smoothest fall at the centers of the edges (M’s). In fact, this unique topology mimics a general variation of the EMDs across the metal-insulator transition in condensed matters. Such an anisotropic broadening effect is indeed observed by momentum-density-based experiments e.g. x-ray Compton scattering.