Proapoptotic and immunomodulatory effects of SYK inhibitor entospletinib in combination with obinutuzumab in patients with chronic lymphocytic leukaemia.

Spleen tyrosine kinase (SYK) is indispensable in B-cell receptor signalling. SYK inhibitor entospletinib demonstrated clinical efficacy in patients with chronic lymphocytic leukaemia (CLL). However, pharmacodynamic effects of SYK inhibition in CLL cells and immunomodulatory effects of B-cell receptor-signalling inhibitors in patients with CLL are poorly understood. We conducted a phase 2 trial of entospletinib in combination with obinutuzumab, an anti-CD20 antibody, in 17 patients with relapsed/refractory CLL. Pharmacodynamic analysis demonstrated that treatment with entospletinib led to rapid downmodulation of pSTAT3 and the anti-apoptotic protein MCL1 in CLL cells. Meanwhile, 6 months of combination therapy was accompanied by a reduction in interferon-γ secretion in CD4+ T-cells and a reversal of exhausted phenotype, as evidenced by downregulation of PD-1. Thus, SYK inhibition downmodulates MCL-1 and partially restores T-cell immunity in CLL. Trial registration number NCT03010358.

In silico study of Bombyx mori fibroin enhancement by graphene in acidic environment.

Bombyx mori fibroin has been widely used since a long time ago and has become a popular material. Here, we carry out a molecular dynamics simulation-based docking simulation of a small fragment of graphene in order to seek the best binding position on the N-termini domain of Bombyx mori fibroin. We report the best binding position, of which binding free energy falls at -54.8 kJ mol-1, indicating the strong binding. The further analysis of the binding pathway shows that this position is selective for single layered graphene rather than multi-layered graphene within our limited simulation times. Via comparing the RAMAN spectra of the corresponding binding pose of atomic clusters, we report the change in the bands compared with free standing graphene fragments, implying the change in molecular orbitals.

The influence of twist angle on the electronic and phononic band of 2D twisted bilayer SiC.

Silicon carbide has a planar two-dimensional structure; therefore it is a potential material for constructing twisted bilayer systems for applications. In this study, DFT calculations were performed on four models with different twist angles. We chose angles of 21.8°, 17.9°, 13.2°, and 5.1° to estimate the dependence of the electronic and phononic properties on the twist angle. The results show that the band gap of bilayer SiC can be changed proportionally by changing the twist angle. However, there are only small variations in the band gaps, with an increment of 0.24 eV by changing the twist angle from 5.1° to 21.8°. At four considered twist angles, the band gaps decrease significantly when fixing the structure of each layer and pressing the separation distance down to 3.5 Å, 3.0 Å, 2.7 Å, and 2.5 Å. A noteworthy point is that the pressing also makes the band linearly smaller at a certain rate regardless of the twist angles. Meanwhile, the phonon bands are not affected by the value of the twist angle. The optical bands are between 900 cm-1 and 1100 cm-1 and the acoustic bands are between 0 cm-1 and 650 cm-1 at four twist angles.

T Cell-intrinsic Immunomodulatory Effects of TAK-981 (Subasumstat), a SUMO-activating Enzyme Inhibitor, in Chronic Lymphocytic Leukemia.

Novel targeted agents used in therapy of lymphoid malignancies are recognized to have complex immune-mediated effects. Sumoylation, a posttranslational modification of target proteins by small ubiquitin-like modifiers (SUMO), regulates a variety of cellular processes indispensable in immune cell activation. Despite this, the role of sumoylation in T-cell biology in context of cancer is not known. TAK-981 (subasumstat) is a small-molecule inhibitor of the SUMO-activating enzyme (SAE) that forms a covalent adduct with an activated SUMO protein. Using T cells derived from patients with chronic lymphocytic leukemia (CLL), we demonstrate that targeting SAE activates type I IFN response. This is accompanied by largely intact T-cell activation in response to T-cell receptor engagement, with increased expression of CD69 and CD38. Furthermore, TAK-981 decreases regulatory T cell (Treg) differentiation and enhances secretion of IFNγ by CD4+ and CD8+ T cells. These findings were recapitulated in mouse models, suggesting an evolutionarily conserved mechanism of T-cell activation regulated by SUMO modification. Relevant to the consideration of TAK-981 as an effective agent for immunotherapy in hematologic malignancies, we demonstrate that the downstream impact of TAK-981 administration is enhancement of the cytotoxic function of CD8+ T cells, thus uncovering immune implications of targeting sumoylation in lymphoid neoplasia.

Pharmacologic targeting of Nedd8-activating enzyme reinvigorates T-cell responses in lymphoid neoplasia.

Neddylation is a sequential enzyme-based process which regulates the function of E3 Cullin-RING ligase (CRL) and thus degradation of substrate proteins. Here we show that CD8+ T cells are a direct target for therapeutically relevant anti-lymphoma activity of pevonedistat, a Nedd8-activating enzyme (NAE) inhibitor. Pevonedistat-treated patient-derived CD8+ T cells upregulated TNFα and IFNγ and exhibited enhanced cytotoxicity. Pevonedistat induced CD8+ T-cell inflamed microenvironment and delayed tumor progression in A20 syngeneic lymphoma model. This anti-tumor effect lessened when CD8+ T cells lost the ability to engage tumors through MHC class I interactions, achieved either through CD8+ T-cell depletion or genetic knockout of B2M. Meanwhile, loss of UBE2M in tumor did not alter efficacy of pevonedistat. Concurrent blockade of NAE and PD-1 led to enhanced tumor immune infiltration, T-cell activation and chemokine expression and synergistically restricted tumor growth. shRNA-mediated knockdown of HIF-1α, a CRL substrate, abrogated the in vitro effects of pevonedistat, suggesting that NAE inhibition modulates T-cell function in HIF-1α-dependent manner. scRNA-Seq-based clinical analyses in lymphoma patients receiving pevonedistat therapy demonstrated upregulation of interferon response signatures in immune cells. Thus, targeting NAE enhances the inflammatory T-cell state, providing rationale for checkpoint blockade-based combination therapy.

Ab Initio Investigation of the Hydrogen Interaction on Two Dimensional Silicon Carbide.

A series of density functional theory calculations were performed to understand the bonding and interaction of hydrogen adsorption on two-dimensional silicon carbide obtained from molecular dynamics simulation. The converged energy results pointed out that the H atom can sufficiently bond to 2D SiC at the top sites (atop Si and C), of which the most stable adsorption site is TSi. The vibrational properties along with the zero-point energy were incorporated into the energy calculations to further understand the phonon effect of the adsorbed H. Most of the 2D SiC structure deformations caused by the H atoms were found at the adsorbent atom along the vertical axis. For the first time, five SiC defect formations, including the quadrilateral-octagon linear defect (8-4), the silicon interstitial defect, the divacancy (4-10-4) defect, the divacancy (8-4-4-8) defect, and the divacancy (4-8-8-4) defect, were investigated and compared with previous 2D defect studies. The linear defect (8-4) has the lowest formation energy and is most likely to be formed for SiC materials. Furthermore, hydrogen atoms adsorb more readily on the defect surface than on the pristine SiC surface.

Dual BTK/SYK inhibition with CG-806 (luxeptinib) disrupts B-cell receptor and Bcl-2 signaling networks in mantle cell lymphoma.

Aberrant B-cell receptor (BCR) signaling is a key driver in lymphoid malignancies. Bruton tyrosine kinase (BTK) inhibitors that disrupt BCR signaling have received regulatory approvals in therapy of mantle cell lymphoma (MCL). However, responses are incomplete and patients who experience BTK inhibitor therapy failure have dire outcomes. CG-806 (luxeptinib) is a dual BTK/SYK inhibitor in clinical development in hematologic malignancies. Here we investigated the pre-clinical activity of CG-806 in MCL. In vitro treatment with CG-806 thwarted survival of MCL cell lines and patient-derived MCL cells in a dose-dependent manner. CG-806 blocked BTK and SYK activation and abrogated BCR signaling. Contrary to ibrutinib, CG-806 downmodulated the anti-apoptotic proteins Mcl-1 and Bcl-xL, abrogated survival of ibrutinib-resistant MCL cell lines, and partially reversed the pro-survival effects of stromal microenvironment-mimicking conditions in primary MCL cells. Dual BTK/SYK inhibition led to mitochondrial membrane depolarization accompanied by mitophagy and metabolic reprogramming toward glycolysis. In vivo studies of CG-806 demonstrated improved survival in one of the two tested aggressive MCL PDX models. While suppression of the anti-apoptotic Bcl-2 family proteins and NFκB signaling correlated with in vivo drug sensitivity, OxPhos and MYC transcriptional programs were upregulated in the resistant model following treatment with CG-806. BAX and NFKBIA were implicated in susceptibility to CG-806 in a whole-genome CRISPR-Cas9 library screen (in a diffuse large B-cell lymphoma cell line). A high-throughput in vitro functional drug screen demonstrated synergy between CG-806 and Bcl-2 inhibitors. In sum, dual BTK/SYK inhibitor CG-806 disrupts BCR signaling and induces metabolic reprogramming and apoptosis in MCL. The Bcl-2 network is a key mediator of sensitivity to CG-806 and combined targeting of Bcl-2 demonstrates synergy with CG-806 warranting continued exploration in lymphoid malignancies.

Pre-Clinical Activity of Amino-Alcohol Dimeric Naphthoquinones as Potential Therapeutics for Acute Myeloid Leukemia.

BACKGROUND: The clinical outcomes of patients with Acute Myeloid Leukemia (AML) remain unsatisfactory. Therefore the development of more efficacious and better-tolerated therapy for AML is critical. We have previously reported anti-leukemic activity of synthetic halohydroxyl dimeric naphthoquinones (BiQ) and aziridinyl BiQ. OBJECTIVE: This study aimed to improve the potency and bioavailability of BiQ compounds and investigate antileukemic activity of the lead compound in vitro and a human AML xenograft mouse model. METHODS: We designed, synthesized, and performed structure-activity relationships of several rationally designed BiQ analogues with amino alcohol functional groups on the naphthoquinone core rings. The compounds were screened for anti-leukemic activity and the mechanism as well as in vivo tolerability and efficacy of our lead compound was investigated. RESULTS: We report that a dimeric naphthoquinone (designated BaltBiQ) demonstrated potent nanomolar anti-leukemic activity in AML cell lines. BaltBiQ treatment resulted in the generation of reactive oxygen species, induction of DNA damage, and inhibition of indoleamine dioxygenase 1. Although BaltBiQ was tolerated well in vivo, it did not significantly improve survival as a single agent, but in combination with the specific Bcl-2 inhibitor, Venetoclax, tumor growth was significantly inhibited compared to untreated mice. CONCLUSION: We synthesized a novel amino alcohol dimeric naphthoquinone, investigated its main mechanisms of action, reported its in vitro anti-AML cytotoxic activity, and showed its in vivo promising activity combined with a clinically available Bcl-2 inhibitor in a patient-derived xenograft model of AML.

NEDD8-activating enzyme inhibition induces cell cycle arrest and anaphase catastrophe in malignant T-cells.

Peripheral T-cell lymphoma (PTCL) is characterized by poor outcomes. We and others have shown that targeting the NEDD8-activating enzyme (NAE) with an investigational inhibitor pevonedistat deregulates cell cycle and mitosis in lymphoma and leukemia. Here, we report that PTCL is characterized by increased rate of chromosomal instability. NAE inhibition promotes cell cycle arrest and induces multipolar anaphases in T-cell lymphoma cell lines, resulting in apoptosis, also observed in primary malignant PTCL cells treated with pevonedistat. We identified p27Kip1 as a mediator of anaphase catastrophe in these cells. Targeting neddylation with pevonedistat may be a promising approach to treatment of PTCL.

Immunomodulatory effects of pevonedistat, a NEDD8-activating enzyme inhibitor, in chronic lymphocytic leukemia-derived T cells.

Novel targeted agents used in therapy of lymphoid malignancies, such as inhibitors of B-cell receptor-associated kinases, are recognized to have complex immune-mediated effects. NEDD8-activating enzyme (NAE) has been identified as a tractable target in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma. We and others have shown that pevonedistat (TAK-924), a small-molecule inhibitor of NAE, abrogates NF-κB signaling in malignant B cells. However, NF-κB pathway activity is indispensable in immune response, and T-cell function is altered in patients with CLL. Using T cells derived from patients with CLL, we demonstrate that although targeting NAE results in markedly differential expression of NF-κB-regulated genes and downregulation of interleukin (IL)-2 signaling during T-cell activation, T cells evade apoptosis. Meanwhile, NAE inhibition favorably modulates polarization of T cells in vitro, with decreased Treg differentiation and a shift toward TH1 phenotype, accompanied by increased interferon-γ production. These findings were recapitulated in vivo in immunocompetent mouse models. T cells exposed to pevonedistat in washout experiments, informed by its human pharmacokinetic profile, recover NAE activity, and maintain their response to T-cell receptor stimulation and cytotoxic potential. Our data shed light on the potential immune implications of targeting neddylation in CLL and lymphoid malignancies.

Pharmacologic Targeting of Mcl-1 Induces Mitochondrial Dysfunction and Apoptosis in B-Cell Lymphoma Cells in a TP53- and BAX-Dependent Manner.

PURPOSE: Bcl-2 has been effectively targeted in lymphoid malignancies. However, resistance is inevitable, and novel approaches to target mitochondrial apoptosis are necessary. AZD5991, a selective BH3-mimetic in clinical trials, inhibits Mcl-1 with high potency. EXPERIMENTAL DESIGN: We explored the preclinical activity of AZD5991 in diffuse large B-cell lymphoma (DLBCL) and ibrutinib-resistant mantle cell lymphoma (MCL) cell lines, MCL patient samples, and mice bearing DLBCL and MCL xenografts using flow cytometry, immunoblotting, and Seahorse respirometry assay. Cas9 gene editing and ex vivo functional drug screen assays helped identify mechanisms of resistance to Mcl-1 inhibition. RESULTS: Mcl-1 was expressed in DLBCL and MCL cell lines and primary tumors. Treatment with AZD5991 restricted growth of DLBCL cells independent of cell of origin and overcame ibrutinib resistance in MCL cells. Mcl-1 inhibition led to mitochondrial dysfunction as manifested by mitochondrial membrane depolarization, decreased mitochondrial mass, and induction of mitophagy. This was accompanied by impairment of oxidative phosphorylation. TP53 and BAX were essential for sensitivity to Mcl-1, and oxidative phosphorylation was implicated in resistance to Mcl-1 inhibition. Induction of prosurvival proteins (e.g., Bcl-xL) in stromal conditions that mimic the tumor microenvironment rendered protection of primary MCL cells from Mcl-1 inhibition, while BH3-mimetics targeting Bcl-2/xL sensitized lymphoid cells to AZD5991. Treatment with AZD5991 reduced tumor growth in murine lymphoma models and prolonged survival of MCL PDX mice. CONCLUSIONS: Selective targeting Mcl-1 is a promising therapeutic approach in lymphoid malignancies. TP53 apoptotic network and metabolic reprogramming underlie susceptibility to Mcl-1 inhibition.

Cyclin-Dependent Kinase-9 Is a Therapeutic Target in MYC-Expressing Diffuse Large B-Cell Lymphoma.

Deregulation of the MYC transcription factor is a key driver in lymphomagenesis. MYC induces global changes in gene expression that contribute to cell growth, proliferation, and oncogenesis by stimulating the activity of RNA polymerases. A key feature in its ability to stimulate RNA Pol II activity is recruitment of pTEFb, an elongation factor whose catalytic core comprises CDK9/cyclin T complexes. Hence, MYC expression and function may be susceptible to CDK9 inhibition. We conducted a pre-clinical assessment of AZ5576, a selective CDK9 inhibitor, in diffuse large B-cell lymphoma (DLBCL). The in vitro and in vivo effects of AZ5576 on apoptosis, cell cycle, Mcl-1, and MYC expression were assessed by flow cytometry, immunoblotting, qPCR and RNA-Seq. We demonstrate that, in addition to depleting Mcl-1, targeting CDK9 disrupts MYC oncogenic function. Treatment with AZ5576 inhibited growth of DLBCL cell lines in vitro and in vivo, independent of cell-of-origin. CDK9 inhibition downregulated Mcl-1 and MYC mRNA transcript and protein in a dose-dependent manner. MYC-expressing cell lines demonstrated enhanced susceptibility to AZ5576. CDK9 inhibition promoted turnover of MYC protein, and decreased MYC phosphorylation at the stabilizing Ser62 residue and downregulated MYC transcriptional targets in DLBCL cells, a finding confirmed in a functional reporter assay, suggesting that CDK9 may govern MYC protein turnover, thus regulating its expression through multiple mechanisms. Our data suggest that targeting CDK9 is poised to disrupt MYC oncogenic activity in DLBCL and provide rationale for clinical development of selective CDK9 inhibitors.