MHC-I upregulation safeguards neoplastic T cells in the skin against NK cell-mediated eradication in mycosis fungoides.

Cancer-associated immune dysfunction is a major challenge for effective therapies. The emergence of antibodies targeting tumor cell-surface antigens led to advancements in the treatment of hematopoietic malignancies, particularly blood cancers. Yet their impact is constrained against tumors of hematopoietic origin manifesting in the skin. In this study, we employ a clonality-supervised deep learning methodology to dissect key pathological features implicated in mycosis fungoides, the most common cutaneous T-cell lymphoma. Our investigations unveil the prominence of the IL-32ß-major histocompatibility complex (MHC)-I axis as a critical determinant in tumor T-cell immune evasion within the skin microenvironment. In patients' skin, we find MHC-I to detrimentally impact the functionality of natural killer (NK) cells, diminishing antibody-dependent cellular cytotoxicity and promoting resistance of tumor skin T-cells to cell-surface targeting therapies. Through murine experiments in female mice, we demonstrate that disruption of the MHC-I interaction with NK cell inhibitory Ly49 receptors restores NK cell anti-tumor activity and targeted T-cell lymphoma elimination in vivo. These findings underscore the significance of attenuating the MHC-I-dependent immunosuppressive networks within skin tumors. Overall, our study introduces a strategy to reinvigorate NK cell-mediated anti-tumor responses to overcome treatment resistance to existing cell-surface targeted therapies for skin lymphoma.

Th17-associated cytokines IL-17 and IL-23 in inflamed skin of Darier disease patients as potential therapeutic targets.

Darier disease (DD) is a rare, inherited multi-organ disorder associated with mutations in the ATP2A2 gene. DD patients often have skin involvement characterized by malodorous, inflamed skin and recurrent, severe infections. Therapeutic options are limited and inadequate for the long-term management of this chronic disease. The aim of this study was to characterize the cutaneous immune infiltrate in DD skin lesions in detail and to identify new therapeutic targets. Using gene and protein expression profiling assays including scRNA sequencing, we demonstrate enhanced expression of Th17-related genes and cytokines and increased numbers of Th17 cells in six DD patients. We provide evidence that targeting the IL-17/IL-23 axis in a case series of three DD patients with monoclonal antibodies is efficacious with significant clinical improvement. As DD is a chronic, relapsing disease, our findings might pave the way toward additional options for the long-term management of skin inflammation in patients with DD.

Boost of innate immunity cytokines as biomarkers of response to extracorporeal photopheresis in patients with leukaemic cutaneous T-cell lymphoma.

BACKGROUND: Extracorporeal photopheresis (ECP) has emerged as a systemic first-line immunomodulatory therapy in leukaemic cutaneous T-cell lymphoma (L-CTCL) and is now beginning to be utilized in other T-cell-mediated diseases. Although ECP has been used for nearly 30 years, its mechanisms of action are not sufficiently understood, and biomarkers for response are scarce. OBJECTIVES: We aimed to investigate the immunomodulatory effects of ECP on cytokine secretion patterns in patients with L-CTCL, to help elucidate its mechanism of action. METHODS: A total of 25 patients with L-CTCL and 15 healthy donors (HDs) were enrolled in this retrospective cohort study. Concentrations of 22 cytokines were simultaneously quantified by using multiplex bead-based immunoassays. Neoplastic cells in patients' blood were evaluated by flow cytometry. RESULTS: Firstly, we observed a distinct cytokine profile pattern difference between L-CTCLs and HDs. There was a significant loss of tumour necrosis factor (TNF)-α, and significant increase of interleukins (IL)-9, IL-12 and IL-13 in the sera of patients with L-CTCL compared with HDs. Secondly, patients with L-CTCL who received ECP were classified as treatment responders and nonresponders according to the quantitative reduction of malignant burden in their blood. We evaluated cytokine levels in culture supernatants from patients' peripheral blood mononuclear cells (PBMCs) at baseline and 27 weeks after ECP initiation. Strikingly, PBMCs purified from ECP responders released statistically higher concentrations of innate immune cytokines IL-1α, IL-1ß, granulocyte-macrophage colony-stimulating factor (GM-CSF) and TNF-α in comparison with ECP nonresponders. In parallel, responders showed clearance of erythema, reduction of malignant clonal T cells in the blood, and a potent boost of relevant innate immune cytokines in individual patients with L-CTCL. CONCLUSIONS: Taken together, our results demonstrate that ECP stimulates the innate immune network, and facilitates redirection of the tumour-biased immunosuppressive microenvironment towards proactive antitumour immune responses. The alterations of IL-1α, IL-1ß, GM-CSF and TNF-α can be used as biomarkers of response to ECP in patients with L-CTCL.

Oncogenic deubiquitination controls tyrosine kinase signaling and therapy response in acute lymphoblastic leukemia.

Dysregulation of kinase signaling pathways favors tumor cell survival and therapy resistance in cancer. Here, we reveal a posttranslational regulation of kinase signaling and nuclear receptor activity via deubiquitination in T cell acute lymphoblastic leukemia (T-ALL). We observed that the ubiquitin-specific protease 11 (USP11) is highly expressed and associates with poor prognosis in T-ALL. USP11 ablation inhibits leukemia progression in vivo, sparing normal hematopoiesis. USP11 forms a complex with USP7 to deubiquitinate the oncogenic lymphocyte cell-specific protein-tyrosine kinase (LCK) and enhance its activity. Impairment of LCK activity leads to increased glucocorticoid receptor (GR) expression and glucocorticoids sensitivity. Genetic knockout of USP7 improved the antileukemic efficacy of glucocorticoids in vivo. The transcriptional activation of GR target genes is orchestrated by the deubiquitinase activity and mediated via an increase in enhancer-promoter interaction intensity. Our data unveil how dysregulated deubiquitination controls leukemia survival and drug resistance, suggesting previously unidentified therapeutic combinations toward targeting leukemia.

Expression of programmed cell death protein 1 (PD-1) and programmed cell death 1 ligand (PD-L1) in adenocarcinomas of the gastroesophageal junction change significantly after neoadjuvant treatment.

BACKGROUND: The effects of cytotoxic chemotherapy on the expression of programmed cell death 1 (PD-1) and its ligand (PD-L1) in cancer cells and peritumoral cells are unclear. The aim of this study was to investigate the impact of neoadjuvant chemotherapy on PD-1 and PD-L1 expression in adenocarcinomas of the gastroesophageal junction. METHODS: PD-1 and PD-L1 expression in cancer cells and tumor-infiltrating lymphocytes in paired diagnostic biopsies and surgical specimens from patients with pretreated and curatively resected adenocarcinomas of the gastroesophageal junction were evaluated by immunohistochemistry. RESULTS: Paired tumor samples were available from 40 patients. PD-1 expression in cancer cells (p < 0.001; Exact Symmetry Test) and tumor-infiltrating lymphocytes (p < 0.001; Exact Symmetry Test) increased significantly after neoadjuvant therapy. Furthermore, we observed a significant decrease in PD-L1 expression in cancer cells (p = 0.003) after neoadjuvant therapy was observed. CONCLUSION: In this study we could show that tumor-cell expression of PD-1 and PD-L1 was significantly altered in patients with adenocarcinomas of the gastroesophageal junction after receiving neoadjuvant chemotherapy. Based on these observations, patients might profit from the combined use of cytotoxic chemotherapy and the blockade of the PD-1 axis.

Programmed death ligand 2 expression plays a limited role in adenocarcinomas of the gastroesophageal junction after preoperative chemotherapy.

BACKGROUND: The effects of cytotoxic chemotherapy on the expression of programmed death ligand 2 (PD-L2) are unknown and little is known about how the tumor microenvironment changes following neoadjuvant chemotherapy in locally advanced gastroesophageal adenocarcinomas (AEG). Recently, a number of studies reported that cytotoxic chemotherapy affects the expression levels of programmed cell death protein 1 (PD-1) and its ligand 1 (PD-L1). Regarding PD-L2, the second known ligand of PD­1, no data on potential changes in expression patterns in patients with preoperatively treated AEG are available. The aim of this study was to investigate the impact of cytotoxic chemotherapy on PD-L2 expression in patients with resectable AEG. METHODS: Consecutive patients with locally advanced AEG treated with preoperative cytotoxic chemotherapy were included. PD-L2 expression by cancer cells (CCs) and tumor-infiltrating lymphocytes (TILs) was investigated in samples of paired diagnostic biopsies and resected tumor specimens by immunohistochemistry using two different anti-PD-L2 antibodies. RESULTS: Included were 40 patients with AEG and available paired tumor tissue samples. PD-L2 expression was observed in one diagnostic biopsy sample by CCs and in one diagnostic biopsy sample by TILs. There was no difference concerning the expression levels measured by the two antibodies. CONCLUSION: In contrast to previously published studies reporting PD-L2 expression rates of up to 50% in AEGs, in our cohort, PD-L2 expression seems to play no significant role in AEG.

DYRK1A regulates B cell acute lymphoblastic leukemia through phosphorylation of FOXO1 and STAT3.

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

Repurposing anthelmintic agents to eradicate resistant leukemia.

Despite rapid progress in genomic profiling in acute lymphoblastic leukemia (ALL), identification of actionable targets and prediction of response to drugs remains challenging. To identify specific vulnerabilities in ALL, we performed a drug screen using primary human ALL samples cultured in a model of the bone marrow microenvironment combined with high content image analysis. Among the 2487 FDA-approved compounds tested, anthelmintic agents of the class of macrocyclic lactones exhibited potent anti-leukemia activity, similar to the already known anti-leukemia agents currently used in induction chemotherapy. Ex vivo validation in 55 primary ALL samples of both precursor B cell and T-ALL including refractory relapse cases confirmed strong anti-leukemia activity with IC50 values in the low micromolar range. Anthelmintic agents increased intracellular chloride levels in primary leukemia cells, inducing mitochondrial outer membrane depolarization and cell death. Supporting the notion that simultaneously targeting cell death machineries at different angles may enhance the cell death response, combination of anthelmintic agents with the BCL-2 antagonist navitoclax or with the chemotherapeutic agent dexamethasone showed synergistic activity in primary ALL. These data reveal anti-leukemia activity of anthelmintic agents and support exploiting drug repurposing strategies to identify so far unrecognized anti-cancer agents with potential to eradicate even refractory leukemia.

Constitutive Activation of RAS/MAPK Pathway Cooperates with Trisomy 21 and Is Therapeutically Exploitable in Down Syndrome B-cell Leukemia.

PURPOSE: Children with Down syndrome (constitutive trisomy 21) that develop acute lymphoblastic leukemia (DS-ALL) have a 3-fold increased likelihood of treatment-related mortality coupled with a higher cumulative incidence of relapse, compared with other children with B-cell acute lymphoblastic leukemia (B-ALL). This highlights the lack of suitable treatment for Down syndrome children with B-ALL. EXPERIMENTAL DESIGN: To facilitate the translation of new therapeutic agents into clinical trials, we built the first preclinical cohort of patient-derived xenograft (PDX) models of DS-ALL, comprehensively characterized at the genetic and transcriptomic levels, and have proven its suitability for preclinical studies by assessing the efficacy of drug combination between the MEK inhibitor trametinib and conventional chemotherapy agents. RESULTS: Whole-exome and RNA-sequencing experiments revealed a high incidence of somatic alterations leading to RAS/MAPK pathway activation in our cohort of DS-ALL, as well as in other pediatric B-ALL presenting somatic gain of the chromosome 21 (B-ALL+21). In murine and human B-cell precursors, activated KRASG12D functionally cooperates with trisomy 21 to deregulate transcriptional networks that promote increased proliferation and self renewal, as well as B-cell differentiation blockade. Moreover, we revealed that inhibition of RAS/MAPK pathway activation using the MEK1/2 inhibitor trametinib decreased leukemia burden in several PDX models of B-ALL+21, and enhanced survival of DS-ALL PDX in combination with conventional chemotherapy agents such as vincristine. CONCLUSIONS: Altogether, using novel and suitable PDX models, this study indicates that RAS/MAPK pathway inhibition represents a promising strategy to improve the outcome of Down syndrome children with B-cell precursor leukemia.

The Leukemogenic TCF3-HLF Complex Rewires Enhancers Driving Cellular Identity and Self-Renewal Conferring EP300 Vulnerability.

The chimeric transcription factor TCF3-HLF defines an incurable acute lymphoblastic leukemia subtype. Here we decipher the regulome of endogenous TCF3-HLF and dissect its essential transcriptional components and targets by functional genomics. We demonstrate that TCF3-HLF recruits HLF binding sites at hematopoietic stem cell/myeloid lineage associated (super-) enhancers to drive lineage identity and self-renewal. Among direct targets, hijacking an HLF binding site in a MYC enhancer cluster by TCF3-HLF activates a conserved MYC-driven transformation program crucial for leukemia propagation in vivo. TCF3-HLF pioneers the cooperation with ERG and recruits histone acetyltransferase p300 (EP300), conferring susceptibility to EP300 inhibition. Our study provides a framework for targeting driving transcriptional dependencies in this fatal leukemia.

Prediction of venetoclax activity in precursor B-ALL by functional assessment of apoptosis signaling.

Deregulated cell death pathways contribute to leukemogenesis and treatment failure in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Intrinsic apoptosis signaling is regulated by different proapoptotic and antiapoptotic molecules: proapoptotic BCL-2 homology domain 3 (BH3) proteins activate prodeath molecules leading to cellular death, while antiapoptotic molecules including B-cell lymphoma 2 (BCL-2) prevent activation of prodeath proteins and counter-regulate apoptosis induction. Inhibition of these antiapoptotic regulators has become a promising strategy for anticancer treatment, but variable anticancer activities in different malignancies indicate the need for upfront identification of responsive patients. Here, we investigated the activity of the BCL-2 inhibitor venetoclax (VEN, ABT-199) in B-cell precursor acute lymphoblastic leukemia and found heterogeneous sensitivities in BCP-ALL cell lines and in a series of patient-derived primografts. To identify parameters of sensitivity and resistance, we evaluated genetic aberrations, gene-expression profiles, expression levels of apoptosis regulators, and functional apoptosis parameters analyzed by mitochondrial profiling using recombinant BH3-like peptides. Importantly, ex vivo VEN sensitivity was most accurately associated with functional BCL-2 dependence detected by BH3 profiling. Modeling clinical application of VEN in a preclinical trial in a set of individual ALL primografts, we identified that leukemia-free survival of VEN treated mice was precisely determined by functional BCL-2 dependence. Moreover, the predictive value of ex vivo measured functional BCL-2 dependence for preclinical in vivo VEN response was confirmed in an independent set of primograft ALL including T- and high risk-ALL. Thus, integrative analysis of the apoptosis signaling indicating mitochondrial addiction to BCL-2 accurately predicts antileukemia activity of VEN, robustly identifies VEN-responsive patients, and provides information for stratification and clinical guidance in future clinical applications of VEN in patients with ALL.

Associations Between Sleep Quality and Migraine Frequency: A Cross-Sectional Case-Control Study.

Migraine has been associated with sleep disturbances. Relationship between sleep quality and migraine frequency is yet to be determined. The present study aimed to investigate sleep disturbances among low-frequency, moderate-frequency, high-frequency, and chronic migraineurs, with and without auras, with well-controlled confounding variables.This cross-sectional controlled study included 357 subjects from an outpatient headache clinic in Taiwan. Standardized questionnaires were utilized to collect demographic, migraine, sleep, depression, anxiety, and restless leg syndrome characteristics in all participants. According to frequency of migraine attacks, patients were divided into 4 groups: with 1 to 4 migraine days per month, 5 to 8 migraine days in a month, 9 to 14 migraine days in a month, and >14 migraine days per month. The Pittsburgh Sleep Quality Index (PSQI) and subgroup items were used to evaluate sleep quality. The association between migraine frequency and sleep quality was investigated using multivariable linear regression and logistic regression.The PSQI total score was highest in patients with high frequent migraine (10.0 ±â€Š3.4) and lowest in controls (7.0 ±â€Š3.4) with a significant trend analysis (P for trend = 0.006). Migraine frequency had an independent effect on the items "Cannot get to sleep within 30 minutes" (P < 0.001), "Wake up in the middle of the night or early morning" (P < 0.001), "Bad dreams" (P = 0.001), "Pain" (P = 0.004), and "Quality of sleep" (P < 0.001). The result showed the effect of migraine frequency in both the aura-present (P for trend = 0.008) and the aura-absent subgroups (P for trend = 0.011).High migraine frequency correlates with poor sleep quality and a higher prevalence of poor sleepers. These associations occur in migraine with aura and without aura.

Hierarchical clustering of breast cancer methylomes revealed differentially methylated and expressed breast cancer genes.

Oncogenic transformation of normal cells often involves epigenetic alterations, including histone modification and DNA methylation. We conducted whole-genome bisulfite sequencing to determine the DNA methylomes of normal breast, fibroadenoma, invasive ductal carcinomas and MCF7. The emergence, disappearance, expansion and contraction of kilobase-sized hypomethylated regions (HMRs) and the hypomethylation of the megabase-sized partially methylated domains (PMDs) are the major forms of methylation changes observed in breast tumor samples. Hierarchical clustering of HMR revealed tumor-specific hypermethylated clusters and differential methylated enhancers specific to normal or breast cancer cell lines. Joint analysis of gene expression and DNA methylation data of normal breast and breast cancer cells identified differentially methylated and expressed genes associated with breast and/or ovarian cancers in cancer-specific HMR clusters. Furthermore, aberrant patterns of X-chromosome inactivation (XCI) was found in breast cancer cell lines as well as breast tumor samples in the TCGA BRCA (breast invasive carcinoma) dataset. They were characterized with differentially hypermethylated XIST promoter, reduced expression of XIST, and over-expression of hypomethylated X-linked genes. High expressions of these genes were significantly associated with lower survival rates in breast cancer patients. Comprehensive analysis of the normal and breast tumor methylomes suggests selective targeting of DNA methylation changes during breast cancer progression. The weak causal relationship between DNA methylation and gene expression observed in this study is evident of more complex role of DNA methylation in the regulation of gene expression in human epigenetics that deserves further investigation.

Globo-H ceramide shed from cancer cells triggers translin-associated factor X-dependent angiogenesis.

Tumor angiogenesis is a critical element of cancer progression, and strategies for its selective blockade are still sought. Here, we examine the angiogenic effects of Globo-H ceramide (GHCer), the most prevalent glycolipid in a majority of epithelial cancers and one that acts as an immune checkpoint. Here, we report that GHCer becomes incorporated into endothelial cells through the absorption of microvesicles shed from tumor cells. In endothelial cells, GHCer addition induces migration, tube formation, and intracellular Ca(2+) mobilization in vitro and angiogenesis in vivo. Breast cancer cells expressing high levels of GHCer displayed relatively greater tumorigenicity and angiogenesis compared with cells expressing low levels of Globo-H. Clincally, GHCer(+) breast cancer specimens contained higher vessel density than GHCer(-) breast cancer specimens. Mechanistic investigations linked the angiogenic effects of GHCer to its endocytosis and binding to TRAX, with consequent release of PLCß1 from TRAX to trigger Ca(2+) mobilization. Together, our findings highlight the importance of GHC as a target for cancer therapy by providing new information on its key role in tumor angiogenesis.

α-Galactosylceramide but not phenyl-glycolipids induced NKT cell anergy and IL-33-mediated myeloid-derived suppressor cell accumulation via upregulation of egr2/3.

Strategies for cancer immunotherapy include activating immune system for therapeutic benefit or blockade of immune checkpoints. To harness innate immunity to fight cancer, α-galactosylceramide (α-GalCer) has been used to activate NKT cells. Unfortunately, administration of α-GalCer causes long-term NKT cell anergy, but the molecular mechanism is unclear. In this study, we showed that α-GalCer-triggered egr2/3, which induced programmed death 1 and cbl-b in NKT cells, leading to NKT cell anergy. We also uncovered the induction of the immunosuppressive myeloid-derived suppressor cells (MDSCs) in the spleen by α-GalCer that might attenuate its antitumor efficacy. The accumulation of MDSC was accompanied by 20-fold rise in their arg-1 mRNAs and enhanced expression of programmed death 1/programmed death ligand 1. Furthermore, α-GalCer-induced egr-2/3 in hepatic NKT cells upregulated their TRAIL in addition to Fas ligand (FasL) and induced alarm signaling molecule IL-33 in Kupffer cells, presumably because of liver damage triggered by TRAIL/FasL. We further demonstrated that IL-33-stimulated macrophages produce G-CSF, which in turn, boosted MDSCs. Thus, α-GalCer-induced FasL/TRAIL and IL-33 provided a novel mechanism underlying α-GalCer-induced hepatotoxicity and MDSC accumulation. In contrast, analogs of α-GalCer containing phenyl group in the lipid tail could neither induce NKT anergy nor enhance MDSCs accumulation. Furthermore, tumor-infiltrating MDSCs in mice injected repeatedly with α-GalCer were 2-fold higher than those treated with phenyl-glycolipids. These results not only revealed the induction of MDSC via IL-33 as a new mechanism for α-GalCer-elicited immunosuppression but also provided one of the mechanisms underlying the superior antitumor potency of phenyl-glycolipids. Our findings have important implications for the development of NKT-stimulatory glycolipids as vaccine adjuvants and anticancer therapeutics.

Common altered epigenomic domains in cancer cells: characterization and subtle variations.

We have previously identified large megabase-sized hypomethylated zones in the genome of the breast cancer cell line MCF-7 using the TspRI-ExoIII technique. In this report, we used a more convenient high throughput method for mapping the hypomethylated zones in a number of human tumor genomes simultaneously. The method was validated by the bisulfite sequencing of 39 randomly chosen sites in a demethylated domain and by bisulfite genome-wide sequencing of the MCF-7 genome. This showed that the genomes of the various tumor cell lines, as well as some primary tumors, exhibit common hypomethylated domains. Interestingly, these hypomethylated domains are correlated with low CpG density distribution genome-wide, together with the histone H3K27Me3 landscape. Furthermore, they are inversely correlated with the H3K9Ac landscape and gene expression as measured in MCF-7 cells. Treatment with drugs resulted in en-bloc changes to the methylation domains. A close examination of the methylation domains found differences between non-invasive and invasive tumors with respect to tumorigenesis related genes. Taken together these results suggest that the human genome is organized in epigenomic domains that contain various different types of genes and imply that there are cis- and trans-regulators that control these domain-wide epigenetic changes and hence gene expression in the human genome. The hypomethylated domains are located in gene deserts that contain mainly tissue-specific genes and therefore we hypothesize that tumor cells keep these regions demethylated and silenced in order to save energy and resources and allow higher levels of cell proliferation and better survival (a thrifty tumor genome hypothesis).

Immunomodulatory and adjuvant activities of a polysaccharide extract of Ganoderma lucidum in vivo and in vitro.

We had isolated a high molecular weight polysaccharide fraction, designated as F3, and performed a comprehensive analysis of its immunomodulatory and adjuvant activities in vivo and in vitro. In vivo, F3-treated mice showed an increase in the number of dendritic cells as well as CD4, CD8, regulatory T, B, plasma, NK, and NKT cells in the spleen. F3 also elevated the levels of multiple cytokines and chemokines in the blood of mice. F3 displayed potent adjuvant activity for tetanus toxoid in the absence of alum and potentiated antibody responses to alum-containing tetanus toxoid in mice. In addition, F3 also boosted Th1 and Th2 response in vivo. In vitro, F3 induced the maturation of dendritic cells derived from human monocytes by upregulating CD40, CD54, CD80, CD83, CD86, and HLA-DR, enhanced mixed lymphocyte reaction, and stimulated the production of ten cytokines and six chemokines. In microarray analysis, expressions of 7688 genes were modulated in dendritic cells after treatment with F3, including cytokine and chemokine genes. These results provide F3 polysaccharide extract further insight into the mechanisms of action for these immunomodulatory and adjuvant activities of from Ganoderma lucidum and also offer preclinical evidence for its development as a vaccine adjuvant.

A tomato bZIP transcription factor, SlAREB, is involved in water deficit and salt stress response.

Abiotic stresses such as cold, water deficit, and salt stresses severely reduce crop productivity. Tomato (Solanum lycopersicum) is an important economic crop; however, not much is known about its stress responses. To gain insight into stress-responsive gene regulation in tomato plants, we identified transcription factors from a tomato cDNA microarray. An ABA-responsive element binding protein (AREB) was identified and named SlAREB. In tomato protoplasts, SlAREB transiently transactivated luciferase reporter gene expression driven by AtRD29A (responsive to dehydration) and SlLAP (leucine aminopeptidase) promoters with exogenous ABA application, which was suppressed by the kinase inhibitor staurosporine, indicating that an ABA-dependent post-translational modification is required for the transactivation ability of SlAREB protein. Electrophoretic mobility shift assays showed that the recombinant DNA-binding domain of SlAREB protein is able to bind AtRD29A and SlLAP promoter regions. Constitutively expressed SlAREB increased tolerance to water deficit and high salinity stresses in both Arabidopsis and tomato plants, which maintained PSII and membrane integrities as well as water content in plant bodies. Overproduction of SlAREB in Arabidopsis thaliana and tomato plants regulated stress-related genes AtRD29A, AtCOR47, and SlCI7-like dehydrin under ABA and abiotic stress treatments. Taken together, these results show that SlAREB functions to regulate some stress-responsive genes and that its overproduction improves plant tolerance to water deficit and salt stress.