Selinexor With Anti-PD-1 Antibody as a Potentially Effective Regimen for Patients With Natural Killer/T-Cell Lymphoma Failing Prior L-Asparaginase and PD-1 Blockade.

BACKGROUND: Natural killer/T-cell lymphoma (NKTCL) is a rare and heterogeneous tumor type of non-Hodgkin's lymphoma (NHL) with a poor clinical outcome. There is no standardized salvage treatment failing l-asparaginase-based regimens. Here we report our retrospective results of the combined use of selinexor and PD-1 blockade (tislelizumab) in 5 patients with NKTCL who had exhausted almost all available treatments. PATIENTS AND METHODS: A total of 5 patients with relapsed/refractory(R/R) NK/T-cell lymphomas failing prior l-asparaginase and anti-PD-1 antibody were retrospectively collected. They were treated with at least one cycle of XPO1 inhibitor plus the same anti-PD-1 antibody. Anti-PD-1 antibody (Tislelizumab) was administrated at 200 mg on day 1 every 3 weeks and selinexor doses and schedules ranged from 40 mg weekly for 2 weeks per 21-day cycle to 60 mg weekly per cycle. RESULTS: Five patients with relapsed NKTCL with extensive organ involvement including 4 central nervous system (CNS) infiltration patients were included. Four patients achieved objective responses including 3 complete responses (CR) and 1 partial response (PR). After a median follow-up time of 14.5 (range, 5-22) months, 1 patient was still in remission with CR, and the other 4 patients discontinued due to disease progression with a median progression-free survival (PFS) of 6 months and median overall survival (OS) of 12 months. Four patients with CNS involvement achieved a median OS of 8 months. Our data suggest that selinexor in combination with an anti-PD-1 antibody is a promising small molecule and immunotherapy combination regimen for patients with relapsed or refractory NKTCL.

Induction with MEDA regimen and consolidation with Auto-HSCT for stage IV NKTCL patients: A prospective multicenter study.

Optimal treatment strategies for natural killer/T-cell lymphoma (NKTCL) patients with stage IV disease have not been well defined. In this prospective phase 2 study, we evaluated the treatment using MEDA (methotrexate, etoposide, dexamethasone and pegaspargase) as induction chemotherapy and autologous hematopoietic stem cell transplantation (Auto-HSCT) for consolidation. Patients with stage IV disease without prior L-asparaginase-based chemotherapy were eligible. Four cycles of MEDA were administered as induction treatment. Patients with complete response (CR, necessary to have complete metabolic remission of PET/CT, negative plasma EBV-DNA and negative EBER staining of bone marrow biopsy tissue) were consolidated by Auto-HSCT. A total of 53 patients were enrolled. The overall response (OR) rate and CR rate after four cycles of MEDA chemotherapy were 75.5% and 56.6%, respectively. Among them, 25 patients underwent Auto-HSCT. The 4-year overall survival (OS) rate and progression-free survival (PFS) rate were 58.0% (95% CI, 43.4%-70.0%) and 43.4% (95% CI, 29.9%-56.1%), respectively. Patients who underwent Auto-HSCT had a 4-year OS rate of 92.0% (95% CI, 71.6%-97.9%) and a 4-year PFS rate of 80.0% (95% CI, 58.4%-91.1%). Grade 3/4 neutropenia and thrombocytopenia occurred in 28.3% and 17.0% of the patients, respectively. MEDA chemotherapy is an effective induction regimen with reduced grade 3/4 hematological toxicities for stage IV NKTCL. Consolidation with Auto-HSCT can be considered as a potential approach to improve the long-term survival of CR patients after induction treatment.

GELAD chemotherapy with sandwiched radiotherapy for patients with newly diagnosed stage IE/IIE natural killer/T-cell lymphoma: a prospective multicentre study.

Early-stage natural killer/T-cell lymphoma (NK/TCL) patients usually receive a combination of chemotherapy and radiotherapy, but the optimal treatment approach has not yet been established. This study aimed to investigate the efficacy and safety profile of a novel chemotherapy regimen and sandwiched radiotherapy in early-stage NK/TCL. Patients with newly diagnosed stage IE/IIE disease were eligible. Patients were initially treated with two courses of the GELAD regimen (gemcitabine 1·0 g/m2 day 1, etoposide 60 mg/m2 days 1-3, pegaspargase 2000 units/m2 day 4, and dexamethasone 40 mg days 1-4), followed by intensity-modulated radiotherapy (IMRT; 50-56 Gy in 25-28 fractions) and two additional courses of GELAD chemotherapy. A total of 52 patients were enrolled. The overall response rate and complete response rate per Lugano 2014 criteria were 94·2% and 92·3% respectively. With a median follow-up of 32 months, the estimated four-year overall survival rate and progression-free survival rate were 94·2% [95% confidence interval (CI), 83·2% to 93·1%] and 90·4% (95% CI, 78·4% to 95·9%) respectively. The most common adverse events were related to pegaspargase. Haematological toxicities were mild, with grade 3/4 neutropenia in 15·4% of patients. Our study provides a new approach with high activity and improved safety for the treatment of early-stage NK/TCL patients. This study was registered at www.clinicaltrials.gov as NCT02733458.

Tapered-open-cavity-based in-line Mach-Zehnder interferometer for highly sensitive axial-strain measurement.

An in-line Mach-Zehnder interferometer based on a multimode-fiber-assisted tapered open-cavity (TOC) is proposed. Light field distributions of the TOC were investigated using beam propagation method with different offsets and diameters of the taper waist. Bias and uniform taper (BT and UT)-based structures were fabricated and compared using one- and two-step arc-discharge methods, and comprehensive tests were then conducted considering axial-strain. The experimental results show that the UT structure has more than -45 pm/µÉ› linear wavelength shift with the applied axial-strain. Owing to its compact size and low cost, the proposed sensor is promising for axial-strain-related high-precision engineering applications.

MHAU-Net: Skin Lesion Segmentation Based on Multi-Scale Hybrid Residual Attention Network.

Melanoma is a main factor that leads to skin cancer, and early diagnosis and treatment can significantly reduce the mortality of patients. Skin lesion boundary segmentation is a key to accurately localizing a lesion in dermoscopic images. However, the irregular shape and size of the lesions and the blurred boundary of the lesions pose significant challenges for researchers. In recent years, pixel-level semantic segmentation strategies based on convolutional neural networks have been widely used, but many methods still suffer from the inaccurate segmentation of fuzzy boundaries. In this paper, we proposed a multi-scale hybrid attentional convolutional neural network (MHAU-Net) for the precise localization and segmentation of skin lesions. MHAU-Net has four main components: multi-scale resolution input, hybrid residual attention (HRA), dilated convolution, and atrous spatial pyramid pooling. Multi-scale resolution inputs provide richer visual information, and HRA solves the problem of blurred boundaries and enhances the segmentation results. The Dice, mIoU, average specificity, and sensitivity on the ISIC2018 task 1 validation set were 93.69%, 90.02%, 92.7% and 93.9%, respectively. The segmentation metrics are significantly better than the latest DCSAU-Net, UNeXt, and U-Net, and excellent segmentation results are achieved on different datasets. We performed model robustness validations on the Kvasir-SEG dataset with an overall sensitivity and average specificity of 95.91% and 96.28%, respectively.

Inhibition of mitochondrial complex III induces differentiation in acute myeloid leukemia.

Although acute myeloid leukemia (AML) is a highly heterogeneous disease with diverse genetic subsets, one hallmark of AML blasts is myeloid differentiation blockade. Extensive evidence has indicated that differentiation induction therapy represents a promising treatment strategy. Here, we identified that the pharmacological inhibition of the mitochondrial electron transport chain (ETC) complex III by antimycin A inhibits proliferation and promotes cellular differentiation of AML cells. Mechanistically, we showed that the inhibition of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in de novo pyrimidine biosynthesis, is involved in antimycin A-induced differentiation. The activity of antimycin A could be reversed by supplement of excessive amounts of exogenous uridine as well as orotic acid, the product of DHODH. Furthermore, we also found that complex III inhibition exerts a synergistic effect in differentiation induction combined with DHODH inhibitor brequinar as well as with the pyrimidine salvage pathway inhibitor dipyridamole. Collectively, our study uncovered the link between mitochondrial complex III and AML differentiation and may provide further insight into the potential application of mitochondrial complex III inhibitor as a mono or combination treatment in differentiation therapy of AML.

Enhanced alleviation of aGVHD by TGF-ß1-modified mesenchymal stem cells in mice through shifting MΦ into M2 phenotype and promoting the differentiation of Treg cells.

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is the only curative method in treating haematologic malignant diseases. Graft-versus-host disease (GVHD) is a common complication post-allo-HSCT, which can be life-threatening. Mesenchymal stem cells (MSCs) as an adult stem cell with immunoregulatory function have demonstrated efficacy in steroid resistant acute GVHD (aGVHD). However, the outcome of aGVHD treated with MSCs in clinical trials varied and its underlying mechanism is still unclear. TGF-ß1 is a potent cytokine, which plays a key role in immunoregulation. In the present study, we firstly transduced the lentivirus vector containing TGF-ß1 gene with mouse bone marrow-derived MSCs. Then, we investigated the immunosuppressive effect of TGF-ß1 gene-modified MSCs on lymphocytes in vitro and its preventive and therapeutical effects on murine aGVHD model in vivo. Murine MSC was successfully isolated and identified. TGF-ß1 was efficiently transduced into mouse MSCs, and high level TGF-ß1 was detected. MSC-TGF-ß1 shared the same morphology and immunotypic features of normal MSC. In vitro, MSC-TGF-ß1 showed enhanced immunosuppressive function on lymphocyte proliferation. In vivo, MSC-TGF-ß1 showed enhanced amelioration on the severity of aGVHD both in prophylactic and therapeutic murine models. Finally, the macrophages (MØs) derived from MSC-TGF-ß1-treated mice showed a remarkably increasing of anti-inflammatory M2-like phenotype. Furthermore, the differentiation of CD4+ CD25+ Foxp3+ Treg cells was significantly increased in MSC-TGF-ß1-treated group. Taken together, we proved that MSC-TGF-ß1 showed enhanced alleviation of aGVHD severity in mice by skewing macrophages into a M2 like phenotype or increasing the proportion of Treg cells, which opens a new frontier in the treatment of aGVHD.

WP1130 reveals USP24 as a novel target in T-cell acute lymphoblastic leukemia.

BACKGROUND: T-cell acute lymphoblastic leukemia (T-ALL) is a lymphoid malignancy caused by the oncogenic transformation of immature T-cell progenitors with poor outcomes. WP1130 has shown potent activity against a variety of cancer but whether WP1130 has anti-T-ALL activity is not clear. USP24, one target of WP1130, is one of the largest deubiquitinases and its detailed mechanism is poorly understood. The aim of this study was to explore whether WP1130 could suppress T-ALL and the role of USP24 in T-ALL. METHODS: Molecular docking and cellular thermal shift assay were performed to determine whether and how WP1130 directly interact with USP24. Mitochondrial transmembrane potential assay was measured via Rhodamine 123 staining. USP24 was reactivated using the deactivated CRISPR-associated protein 9 (dCas9)-synergistic activation mediator (SAM) system. The in vivo results were examined by tumor xenografts in NOD-SCID mice. All statistical analyses were performed with the SPSS software package. RESULTS: WP1130 treatment decreased the viability and induces apoptosis of T-ALL cells both in vitro and in vivo. Furthermore, we demonstrated that knockdown of USP24 but not USP9X could significantly induce growth inhibition and apoptosis of T-ALL cells. Oncomine database showed that USP24 expression was upregulated in T-ALL samples and Kaplan-Meier results indicated that the USP24 was negatively but USP9X was positively associated with survival in T-ALL patients. Additionally, we proposed that WP1130 directly interacts with the activity site pocket of USP24 in T-ALL cells, which leads to the decrease of its substrates Mcl-1. Mechanistically, WP1130 induces apoptosis by accelerating the collapse of mitochondrial transmembrane potential via USP24-Mcl-1 axis. CONCLUSIONS: Altogether, using WP1130 as a chemical probe, we demonstrate that USP24 but not USP9X is a novel target in T-ALL cells. Moreover, we uncovered that WP1130 induces apoptosis by accelerating the collapse of mitochondrial transmembrane potential via USP24-Mcl-1 axis. These results provide that USP24-Mcl-1 axis may represent a novel strategy in the treatment of T-ALL and WP1130 is a promising lead compound for developing anti-T-ALL drugs.

Interleukin-10 Gene-Modified Dendritic Cell-Induced Type 1 Regulatory T Cells Induce Transplant-Tolerance and Impede Graft Versus Host Disease After Allogeneic Stem Cell Transplantation.

BACKGROUND/AIMS: Tr1 cells can induce peripheral tolerance to self- and foreign antigens, and have been developed as a therapeutic tool for the induction of tolerance to transplanted tissue. We explored the feasibility of generating Tr1 cells by using IL-10 gene-modified recipient DCs (DCLV-IL-10) to stimulate donor naive CD4+ T cells. We also investigated some biological properties of Tr1 cells. METHODS: DCLV-IL-10 were generated through DCs transduced with a lentivirus vector carrying the IL-10 gene, and Tr1 cells were produced by using DCLV-IL-10 to stimulate naive CD4+ T cells. The effects of Tr1 cells on T-cell proliferation and the occurrence of graft versus host disease (GVHD) following allogeneic stem-cell transplantation (allo-HSCT) were investigated. RESULTS: The DCLV-IL-10-induced Tr1 cells co-expressed LAG-3 and CD49b. Moreover, they also expressed CD4, CD25, and IL-10, but not Foxp3, and secreted significantly higher levels of IL-10 (1,729.36 ± 185.79 pg/mL; P < 0.001) and INF-γ (1,524.48 ± 168.65 pg/mL; P < 0.01) than the control T cells upon the stimulation by allogeneic DCs. Tr1 cells markedly suppressed T-lymphocyte proliferation and the mixed lymphocytic response (MLR) in vitro. The mice used in the allo-HSCT model had longer survival times and lower clinical and pathological GVHD scores than the control mice. CONCLUSION: IL-10 gene-modified DC-induced Tr1 cells may be used as a potent cellular therapy for the prevention of GVHD after allo-HSCT.

Preventive and therapeutic effects of adenanthin on experimental autoimmune encephalomyelitis by inhibiting NF-κB signaling.

Adenanthin, a diterpenoid isolated from the leaves of Isodon adenanthus, has been reported to possess antileukemic activity through targeting peroxiredoxin I/II. However, its other potential activities remain to be explored. Using myelin oligodendrocyte glycoprotein (MOG)35-55-induced experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, we report in this study that adenanthin exerts efficaciously preventive and therapeutic effects on EAE accompanied by significant restriction of infiltration of inflammatory cells and demyelination in CNS. Adenanthin-presented immunomodulatory effects on EAE are correlated with suppressed proliferation of MOG35-55-reactive T cells, decreased Th1 and Th17 cells, increased regulatory T cell populations, decreased production of serum proinflammatory cytokines, and reduced stimulatory capacity of APCs, which might be mediated by its inhibitory action on NF-κB signaling pathway. Our results propose that, as a novel NF-κB inhibitor, adenanthin has potent immunomodulatory activity for the treatment of multiple sclerosis and possibly other autoimmune disorders.

Adenanthin targets peroxiredoxin I and II to induce differentiation of leukemic cells.

Peroxiredoxins (Prxs) are potential therapeutic targets for major diseases such as cancers. However, isotype-specific inhibitors remain to be developed. We report that adenanthin, a diterpenoid isolated from the leaves of Rabdosia adenantha, induces differentiation of acute promyelocytic leukemia (APL) cells. We show that adenanthin directly targets the conserved resolving cysteines of Prx I and Prx II and inhibits their peroxidase activities. Consequently, cellular H(2)O(2) is elevated, leading to the activation of extracellular signal-regulated kinases and increased transcription of CCAAT/enhancer-binding protein ß, which contributes to adenanthin-induced differentiation. Adenanthin induces APL-like cell differentiation, represses tumor growth in vivo and prolongs the survival of mouse APL models that are sensitive and resistant to retinoic acid. Thus, adenanthin can serve as what is to our knowledge the first lead natural compound for the development of Prx I- and Prx II-targeted therapeutic agents, which may represent a promising approach to inducing differentiation of APL cells.

Targeting peroxiredoxins against leukemia.

Peroxiredoxins (Prx), a family of small non-seleno peroxidases, are important regulators for cellular reactive oxygen species (ROS), which contribute to many signaling pathways and pathogenesis of diseases. Targeting redox homeostasis is being developed as a promising therapeutic strategy for many diseases such as cancers. This mini-review attempts to focus on our recent discoveries on adenanthin as the first natural molecule to specifically target the resolving cysteines of Prx I and Prx II and thus inhibit their peroxidase activities, and its role in differentiation induction in vitro and in vivo of acute myeloid leukemic cells.

Structural Modification of Noscapine via Photoredox/Nickel Dual Catalysis for the Discovery of S-Phase Arresting Agents.

Herein, we disclose a powerful strategy for the functionalization of the antitumor natural alkaloid noscapine by utilizing photoredox/nickel dual-catalytic coupling technology. A small collection of 37 new noscapinoids with diverse (hetero)alkyl and (hetero)cycloalkyl groups and enhanced sp3 character was thus synthesized. Further in vitro antiproliferative activity screening and SAR study enabled the identification of 6o as a novel, potent, and less-toxic anticancer agent. Furthermore, 6o exerts superior cellular activity via an unexpected S-phase arrest mechanism and could significantly induce cell apoptosis in a dose-dependent manner, thereby further highlighting its potential in drug discovery as a promising lead compound.

Alantolactone induces apoptosis in chronic myelogenous leukemia sensitive or resistant to imatinib through NF-κB inhibition and Bcr/Abl protein deletion.

Alantolactone, an allergenic sesquiterpene lactone, has recently been found to have significant antitumor effects on malignant tumor cells. Here, we investigated the potential effect of alantolactone on Bcr/Abl+ imatinib-sensitive and -resistant cells. Alantolactone treatment resulted in obvious apoptosis in both imatinib-sensitive and -resistant K562 cells, as shown by the increase in Annexin V-positive cells, caspase-3 activation, poly(ADP-ribose) polymerase-1 (PARP-1) cleavage and mitochondrial membrane potential collapse. Alantolactone significantly inhibited NF-κB-dependent reporter gene activity, decreased the DNA-binding activity of NF-ОκB, and blocked TNF-α-induced IκBα phosphorylation. Of interest, the oncogenic Bcr/Abl fusion protein but not its mRNA levels were quickly reduced upon alantolactone exposure in imatinib-sensitive and -resistant K562 cells. Bcr/Abl knockdown enhanced the apoptosis driven by alantolactone. Bcr/Abl protein reduction could not be reversed by the addition of proteasome or caspase-3 inhibitors. The overexpression of p65 inhibited alantolactone-induced apoptosis, whereas p65 or Bcr/Abl silencing enhanced its apoptotic-inducing effect. Furthermore, Bcr/Abl-transfected 32D cells showed more sensitivity to alantolactone than vector-transfected control cells, and the Bcr/Abl protein was depleted, as observed in K562 cells. Finally, alantolactone-induced apoptosis was also observed in primary CD34+ CML leukemic cells. Collectively, these findings suggest that alantolactone is a promising potent agent to fight against CML cells via the inhibition of the NF-κB signaling pathway and depletion of the Bcr/Abl protein.

DBE-Net: Dual Boundary-Guided Attention Exploration Network for Polyp Segmentation.

Automatic segmentation of polyps during colonoscopy can help doctors accurately find the polyp area and remove abnormal tissues in time to reduce the possibility of polyps transforming into cancer. However, the current polyp segmentation research still has the following problems: blurry polyp boundaries, multi-scale adaptability of polyps, and close resemblances between polyps and nearby normal tissues. To tackle these issues, this paper proposes a dual boundary-guided attention exploration network (DBE-Net) for polyp segmentation. Firstly, we propose a dual boundary-guided attention exploration module to solve the boundary-blurring problem. This module uses a coarse-to-fine strategy to progressively approximate the real polyp boundary. Secondly, a multi-scale context aggregation enhancement module is introduced to accommodate the multi-scale variation of polyps. Finally, we propose a low-level detail enhancement module, which can extract more low-level details and promote the performance of the overall network. Extensive experiments on five polyp segmentation benchmark datasets show that our method achieves superior performance and stronger generalization ability than state-of-the-art methods. Especially for CVC-ColonDB and ETIS, two challenging datasets among the five datasets, our method achieves excellent results of 82.4% and 80.6% in terms of mDice (mean dice similarity coefficient) and improves by 5.1% and 5.9% compared to the state-of-the-art methods.

Targeting Bcl-xL is a potential therapeutic strategy for extranodal NK/T cell lymphoma.

Extranodal natural killer/T cell lymphoma, nasal type (ENKTL) is an aggressive lymphoid malignancy with a poor prognosis and lacks standard treatment. Targeted therapies are urgently needed. Here we systematically investigated the druggable mechanisms through chemogenomic screening and identified that Bcl-xL-specific BH3 mimetics effectively induced ENKTL cell apoptosis. Notably, the specific accumulation of Bcl-xL, but not other Bcl-2 family members, was verified in ENKTL cell lines and patient tissues. Furthermore, Bcl-xL high expression was shown to be closely associated with worse patient survival. The critical role of Bcl-xL in ENKTL cell survival was demonstrated utilizing selective inhibitors, genetic silencing, and a specific degrader. Additionally, the IL2-JAK1/3-STAT5 signaling was implicated in Bcl-xL dysregulation. In vivo, Bcl-xL inhibition reduced tumor burden, increased apoptosis, and prolonged survival in ENKTL cell line xenograft and patient-derived xenograft models. Our study indicates Bcl-xL as a promising therapeutic target for ENKTL, warranting monitoring in ongoing clinical trials by targeting Bcl-xL.

Knockdown of metallopanstimulin-1 inhibits NF-κB signaling at different levels: the role of apoptosis induction of gastric cancer cells.

The ribosomal protein S27 (metallopanstimulin-1, MPS-1) has been reported to be a multifunctional protein, with increased expression in a number of cancers. We reported previously that MPS-1 was highly expressed in human gastric cancer. Knockdown of MPS-1 led to spontaneous apoptosis and repressed proliferation of human gastric cancer cells in vitro and in vivo. However, how does MPS-1 regulate these processes is unclear. Here we performed microarray and pathway analyses to investigate possible pathways involved in MPS-1 knockdown-induced apoptosis in gastric cancer cells. Our results showed that knockdown of MPS-1 inhibited NF-κB activity by reducing phosphorylation of p65 at Ser536 and IκBα at Ser32, inhibiting NF-κB nuclear translocation, and down-regulating its DNA binding activity. Furthermore, data-mining the Gene-Regulatory-Network revealed that growth arrest DNA damage inducible gene 45ß (Gadd45ß), a direct NF-κB target gene, played a critical role in MPS-1 knockdown-induced apoptosis. Over-expression of Gadd45ß inhibited MPS-1 knockdown-induced apoptosis via inhibition of JNK phosphorylation. Taken together, these data revealed a novel pathway, the MPS-1/NF-κB/Gadd45ß signal pathway, played an important role in MPS-1 knockdown-induced apoptosis of gastric cancer cells. This study sheds new light on the role of MPS-1/NF-κB in apoptosis and the possible use of MPS-1 targeting strategy in the treatment of gastric cancer.

Pharicin B stabilizes retinoic acid receptor-α and presents synergistic differentiation induction with ATRA in myeloid leukemic cells.

All-trans retinoic acid (ATRA), a natural ligand for the retinoic acid receptors (RARs), induces clinical remission in most acute promyelocytic leukemia (APL) patients through the induction of differentiation and/or eradication of leukemia-initiating cells. Here, we identify a novel natural ent-kaurene diterpenoid derived from Isodon pharicus leaves, called pharicin B, that can rapidly stabilize RAR-α protein in various acute myeloid leukemic (AML) cell lines and primary leukemic cells from AML patients, even in the presence of ATRA, which is known to induce the loss of RAR-α protein. Pharicin B also enhances ATRA-dependent the transcriptional activity of RAR-α protein in the promyelocytic leukemia-RARα-positive APL cell line NB4 cells. We also showed that pharicin B presents a synergistic or additive differentiation-enhancing effect when used in combination with ATRA in several AML cell lines and, especially, some primary leukemic cells from APL patients. In addition, pharicin B can overcome retinoid resistance in 2 of 3 NB4-derived ATRA-resistant subclones. These findings provide a good example for chemical biology-based investigations of pathophysiological and therapeutic significances of RAR-α and PML-RAR-α proteins. The effectiveness of the ATRA/pharicin B combination warrants further investigation on their use as a therapeutic strategy for AML patients.

ZCL-082, a boron-containing compound, induces apoptosis of non-Hodgkin's lymphoma via targeting p90 ribosomal S6 kinase 1/NF-κB signaling pathway.

INTRODUCTION: Despite the rapid progress in the diagnosis and treatment, the prognosis of some types of non-Hodgkin's lymphoma (NHL), especially those with double-hit or double-expressor genotypes, remains poor. Novel targets and compounds are needed to improve the prognosis of NHL. METHODS: We investigated the effect of ZCL-082, a novel boron-containing compound with anti-proliferating activity against ovarian cancer cells, on NHL cells and human peripheral blood mononuclear cells by CCK-8 assay, Annexin V/PI double staining assay, RH123/PI double staining, Western blot, and immunohistochemistry. NF-κB pathway activity was analyzed using luciferase reporter gene assay and RT-PCR. The location of p65 was detected by immunofluorescence and nuclear/cytoplasmic fractionation assay. Immunoprecipitation and chromatin immunoprecipitation assays were used to detect the binding between p65 and p300. CETSA and molecular docking assay were carried out to test the interaction between ZCL-082 and p90 ribosomal S6 kinase 1 (RSK1). Kinase reaction was conducted to examine the inhibition of RSK1 kinase activity by ZCL-082. RESULTS: We found that ZCL-082 can induce the apoptosis of various NHL cell lines in vitro and in vivo. ZCL-082 significantly inhibits TNFα- or LPS-induced NF-κB activation without disturbing TNFα-induced IκBα degradation or the nuclear translocation and DNA-binding ability of p65. However, ZCL-082 markedly suppresses the phosphorylation of p65 on Ser536 and the interaction between p65 and p300. The overexpression of the phosphomimetic mutant of p65 at Ser536 partially abrogates ZCL-082-induced cell death. We further found that ZCL-082 directly binds to and inhibits the activity of RSK1. RSK1 can phosphorylate RelA/p65 on Ser536 and its overexpression is associated with the poor prognosis of lymphoma. The overexpression of RSK1 partially rescues ZCL-082-induced cell death. Molecular docking studies show that ZCL-082 fits well with the N-terminal kinase domain of RSK1. Furthermore, the combination of ZCL-082 and BCL-2 inhibitor ABT-199 has a synergistic apoptosis-inducing effect against double-hit lymphoma cell line OCI-Ly10. DISCUSSION: We found that ZCL-082 is a highly promising anti-lymphoma compound that targets RSK1 and interferes with the RSK1/NF-κB signaling pathway. The combination of ZCL-082 with BCL-2 inhibitor may represent a novel strategy to improve the outcome of double-hit or double-expressor lymphoma.

Ikaros is degraded by proteasome-dependent mechanism in the early phase of apoptosis induction.

Ikaros is an important transcription factor involved in the development and differentiation of hematopoietic cells. In this work, we found that chemotherapeutic drugs or ultraviolet radiation (UV) treatment could reduce the expression of full-length Ikaros (IK1) protein in less than 3h in leukemic NB4, Kasumi-1 and Jurkat cells, prior to the activation of caspase-3. Etoposide treatment could not alter the mRNA level of IK1 but it could shorten the half-life of IK1. Co-treatment with the proteasome inhibitor MG132 or epoxomicin but not calpain inhibitor calpeptin inhibited etoposide-induced Ikaros downregulation. Overexpression of IK1 could accelerate etoposide-induced apoptosis in NB4 cells, as evidenced by the increase of Annexin V positive cells and the more early activation of caspase 3. To our knowledge, this is the first report to show that upon chemotherapy drugs or UV treatment, IK1 could be degraded via the proteasome system in the early phase of apoptosis induction. These data might shed new insight on the role of IK1 in apoptosis and the post-translational regulation of IK1.