TRAIL receptor signaling and therapeutics

TRAIL induces cytokine production via the NFkB2 pathway promoting neutrophil chemotaxis and neutrophil-mediated immune-suppression in triple negative breast cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic that induces apoptosis in cancer cells while sparing the non-malignant cells in preclinical models. However, its efficacy in clinical trials has been limited, suggesting unknown mechanisms modulating TRAIL activity in patients. We hypothesized that TRAIL treatment elicits transcriptional changes in triple negative breast cancer (TNBC) cells that alter the immune milieu. RNAseq analysis of MDA-MB-231 cells along with validation in additional cell lines demonstrated that TRAIL induced cytokines such as CXCLs 1, 2, 3, 8,11 and IL-6, which are known to modify neutrophil function. Mechanistically, TRAIL dependent induction of the cytokines was predominantly mediated by death receptor 5, caspase-8 and the non-canonical NFKB2 pathway. These cytokines produced by TRAIL-treated TNBC cells enhanced chemotaxis of normal human donor isolated neutrophils. Using TNBC xenograft models, TRAIL induced activation of NFkB2 pathway, cytokine production and increased neutrophil recruitment into the tumors. Moreover, preincubation of neutrophils in supernatants from TRAIL-treated TNBC cells significantly impaired neutrophil function as measured by reduced respiratory burst and cytotoxic effect against TNBC cells. Transcriptomic analysis of neutrophils incubated with either TRAIL alone or supernatant of TRAIL-treated TNBC cells revealed increased expression of inflammatory cytokines, immune modulatory genes, immune checkpoint genes, and genes implicated in delayed neutrophil apoptosis. Functional studies showed that these neutrophils suppress T cell proliferation and augment Treg suppressive phenotype. Collectively, our study demonstrates a novel role of TRAIL-induced NFKB2-dependent cytokine production that promotes neutrophil chemotaxis and neutrophil-mediated immune suppression.

Association Between Circulating Cytokines and Endometriosis: A Mendelian Randomization Study

Existing evidence shows the importance of circulating cytokines in studying female reproductive system dysfunction. Endometriosis (EM) is thought to be associated with multiple immune cytokines, but its causality has not been proven. Utilising Genome-Wide Association Study (GWAS) data, we performed Mendelian randomisation (MR) to assess causality between 41 cytokines and EM. Positive Single Nucleotide Polymorphisms (SNPs) were annotated via Multi-marker Analysis of GenoMic Annotation (MAGMA) and intersected with EM-associated genes from Weighted Gene Co-expression Network Analysis (WGCNA). Shared genes underwent single-gene Gene Set Enrichment Analysis (GSEA). The association of shared genes with endometriosis was validated by the quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) method. Two-sample MR identified TNF-Related Apoptosis-Inducing Ligand (TRAIL) as causally linked to EM. Inverse variance weighting (IVW) revealed that elevated TRAIL levels reduced EM risk (β = -0.061, p = 2.267e-6). WGCNA identified DSG 2 (a TRAIL-related gene related to EM). Quantitative analysis based on clinical samples confirmed the low expression of DSG 2 in patients with endometriosis. GSEA indicated DSG 2 participation in many signalling pathways. MR analysis revealed that elevated TRAIL levels significantly reduce the risk of EM. MAGMA and WGCNA analyses identified DSG 2 as a key gene associated with TRAIL. Gene expression analysis combined with GSEA suggested that decreased DSG 2 expression may influence the development of EM through various pathways. These results offer new potential diagnostic markers and therapeutic targets for EM.

WTAP-Mediated m6A Modification of TRAIL-DR4 Suppresses MH7A Cell Apoptosis

BACKGROUND

N6-methyladenosine (m6A) is one of the most conserved internal RNA modifications, which has been implicated in many biological processes, such as apoptosis and proliferation. Wilms tumor 1-associating protein (WTAP), as a key component of m6A methylation, is a nuclear protein that has been associated with the regulation of proliferation and apoptosis. Rheumatoid arthritis (RA), a systemic, infiltrating autoimmune disease, is characterized by synovial hyperplasia. However, little is known about the precise role of WTAP in RA. This study investigated the role of the WTAP-mediated m6A modification of TNF-related apoptosis-inducing ligand death receptor 4 (TRAIL-DR4) in RA.

METHOD

Methyltransferase WTAP overexpression plasmids and small interfering RNAs were constructed and transfected into MH7A cells. Immunofluorescence (IF) staining, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and Western blot were used to detect changes in the expression of WTAP, the B-cell lymphoma 2 (BCL2) gene family, BCL2-associated X (BAX) and TRAIL-DR4 expression, and the effects of WTAP overexpression on cell viability, cell cycle, apoptosis, and proliferation were assessed by a cell counting kit-8 (CCK-8), flow cytometry, and transmission electron microscopy (TEM). The m6A modification of TRAIL-DR4 was verified by m6A methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) and its stability was assessed by an actinomycin D assay.

RESULTS

Overexpression of WTAP not only increased the levels of WTAP and BCL2, and decreased the levels of BAX and TRAIL-DR4, but also significantly inhibited MH7A cell apoptosis and promoted cell viability and proliferation, while WTAP silencing led to the opposite trend. The SRAMP online database predicted that TRAIL-DR4 has multiple potential methylation-binding sites, and fluorescence in situ hybridization (FISH) combined with IF showed that WTAP and TRAIL-DR4 were mainly expressed in both the nucleus and cytoplasm. MeRIP-qPCR and actinomycin D analysis experiments revealed that WTAP could promote the m6A level of TRAIL-DR4, decrease the stability of TRAIL-DR4 mRNA, and subsequently inhibit apoptosis.

CONCLUSION

This study suggests that WTAP-mediated m6A modification of TRAIL-DR4 suppresses MH7A cell apoptosis. This discovery offers a new focus and avenue for the clinical treatment of RA, while also extending our understanding of the pathophysiology of RA from the standpoint of m6A alteration.

TRAIL-induced cytokine production via NFKB2 pathway promotes neutrophil chemotaxis and immune suppression in triple negative breast cancers

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic that induces apoptosis in cancer cells while sparing the non-malignant cells in preclinical models. However, its efficacy in clinical trials has been limited, suggesting unknown modulatory mechanisms responsible for the lack of TRAIL activity in patients. Here, we hypothesized that TRAIL treatment elicits transcriptional changes in triple negative breast cancer (TNBC) cells that alter the immune milieu. To test this, we performed an RNAseq analysis of MDA-MB-231 cells treated with TRAIL, followed by validation in additional TNBC cell lines. TRAIL significantly induces expression of multiple cytokines such as CXCLs 1, 2, 3, 8,11 and IL-6, which are known to modify neutrophil function. Mechanistically, the induction of these cytokines was predominantly mediated by death receptor 5, caspase 8 (but not caspase 8 enzymatic activity), and the non-canonical NFKB2 pathway. The cytokines produced by the TRAIL-treated TNBC cells enhanced chemotaxis of healthy human donor isolated neutrophils. In vivo , TRAIL treated TNBC murine xenograft tumors showed activation of the NFKB2 pathway, elevated production of CXCLs and IL-6, and increased neutrophil recruitment into the tumors. Moreover, donor isolated neutrophils preincubated in supernatants from TRAIL-treated TNBC cells exhibited impaired cytotoxic effect against TNBC cells. Transcriptomic analysis of neutrophils incubated with either TRAIL alone or supernatant of TRAIL-treated TNBC cells revealed increased expression of inflammatory cytokines, immune modulatory genes, immune checkpoint genes, and genes implicated in delayed neutrophil apoptosis. Functional studies with these neutrophils confirmed their suppressive effect on T cell proliferation and an increase in Treg suppressive phenotype. Collectively, our study demonstrates a novel role of TRAIL-induced NFKB2-dependent cytokine production that promotes neutrophil chemotaxis and immune suppression.

Significance of TRAIL/Apo-2 ligand and its death receptors in apoptosis and necroptosis signalling: Implications for cancer-targeted therapeutics

The human immune defensesystem routinely expresses the tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), which is the most prevalent element for antitumor immunity. TRAIL associates with its death receptors (DRs), DR4 (TRAIL-R1), and DR5 (TRAIL-R2), in cancer cells to initiate the intracellular apoptosis cascade. Accordingly, numerous academic institutions and pharmaceutical companies havetried to exploreTRAIL's capacity to kill tumourcells by producing recombinant versions of it (rhTRAIL) or TRAIL receptor agonists (TRAs) [monoclonal antibody (mAb), synthetic and natural compounds, etc.] and molecules that sensitize TRAIL signalling pathway for therapeutic applications. Recently, several microRNAs (miRs) have been found to activate or inhibit death receptor signalling. Therefore, pharmacological regulation of these miRs may activate or resensitize the TRAIL DRs signal, and this is a novel approach for developing anticancer therapeutics. In this article, we will discuss TRAIL and its receptors and molecular pathways by which it induces various cell death events. We will unravel potential innovative applications of TRAIL-based therapeutics, and other investigated therapeutics targeting TRAIL-DRs and summarize the current preclinical pharmacological studies and clinical trials. Moreover, we will also emphasizea few situations where future efforts may be addressed to modulate the TRAIL signalling pathway.

Intracellular FGF1 protects cells from apoptosis through direct interaction with p53

Fibroblast growth factor 1 (FGF1) acts by activating specific tyrosine kinase receptors on the cell surface. In addition to this classical mode of action, FGF1 also exhibits intracellular activity. Recently, we found that FGF1 translocated into the cell interior exhibits anti-apoptotic activity independent of receptor activation and downstream signaling. Here, we show that expression of FGF1 increases the survival of cells treated with various apoptosis inducers, but only when wild-type p53 is present. The p53-negative cells were not protected by either ectopically expressed or translocated FGF1. We also confirmed the requirement of p53 for the anti-apoptotic intracellular activity of FGF1 by silencing p53, resulting in loss of the protective effect of FGF1. In contrast, in p53-negative cells, intracellular FGF1 regained its anti-apoptotic properties after transfection with wild-type p53. We also found that FGF1 directly interacts with p53 in cells and that the binding region is located in the DBD domain of p53. We therefore postulate that intracellular FGF1 protects cells from apoptosis by directly interacting with p53.

Regulation of programmed death ligand 1 (PD-L1) expression by TNF-related apoptosis-inducing ligand (TRAIL) in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that lacks targeted therapies. Previous studies have shown that TNBC cells are highly sensitive to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), making it a promising agent for treating TNBC. However, the development of TRAIL resistance limits its further clinical development, and the underlying mechanisms are not fully understood. In this study, we report the role of PD-L1 in TRAIL resistance. Specifically, we found that TRAIL treatment increases PD-L1 expression in TRAIL-sensitive cells and that basal PD-L1 expression is increased in acquired TRAIL-resistant cells. Mechanistically, we found that increased PD-L1 expression was accompanied by increased extracellular signal-regulated kinase (ERK) activation. Using both genetic and pharmacological approaches, we showed that knockdown of ERK by siRNA or inhibition of ERK activation by the mitogen-activated protein kinase kinase inhibitor U0126 decreased PD-L1 expression and increased TRAIL-induced cell death. Furthermore, we found that knockout or knockdown of PD-L1 enhances TRAIL-induced apoptosis, suggesting that PD-L1-mediated TRAIL resistance is independent of its ability to evade immune suppression. Therefore, this study identifies a noncanonical mechanism by which PD-L1 promotes TRAIL resistance, which can be potentially exploited for immune checkpoint therapy.

TRAIL-modified, doxorubicin-embedded periodic mesoporous organosilica nanoparticles for targeted drug delivery and efficient antitumor immunotherapy

Traditional anticancer treatments directly target tumor cells. In contrast, cancer immunotherapy fortifies host immunity. Nanoparticles that incorporate both immunomodulatory and chemotherapeutic agents regulate the tumor microenvironment by activating immune cells and enhancing antitumor immunity. Nanoparticle-based cancer immunotherapy has received considerable attention and has been extensively studied in recent years. In this study, we developed a targeted drug delivery system to enhance immunotherapeutic efficacy and overcome drug resistance by inducing tumor apoptosis and immunogenic cell death (ICD), and activating immune cells. Periodic mesoporous organosilica nanoparticles (PMOs) bore tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on their surfaces, and their inner cores were loaded with doxorubicin (DOX). TRAIL enhanced the nanoparticle-targeting capacity and worked synergistically with DOX against breast cancer cells in vitro and in vivo. Furthermore, we revealed for the first time the ability of PMOs to activate dendritic cells (DCs) and elevate ICD levels of DOX in vitro, and TRAIL further enhances the immunomodulatory function of PMOs. Systemic exposure to DOX@PMO-hT induced an immune response, activated DCs and CD4⁺ and CD8⁺ T cells, and significantly suppressed tumor growth in a 4T1-bearing immunocompetent mouse model. Overall, our study demonstrates that TRAIL-modified, DOX-embedded PMO nanoparticles represent a good candidate for tumor-targeted immunotherapy, which has relatively superior therapeutic efficacy and highly promising future application prospects. STATEMENT OF SIGNIFICANCE: This study revealed for the first time the ability of PMOs to elevate ICD levels and activate DCs in vitro. The results explained the immunomodulatory function of PMOs and demonstrated the synergistic effects of TRAIL and DOX in triple-negative breast cancer. In addition, immunomodulatory effects of the drug delivery vectors constructed in this study were verified in vivo.

Therapeutic Values of Myeloid-Derived Suppressor Cells in Hepatocellular Carcinoma: Facts and Hopes

Simple Summary

Myeloid-derived suppressor cells restrict the effectiveness of immune-checkpoint inhibitors for a subset of patients mainly through thwarting T cell infiltration into tumor sites. Treatments targeting MDSCs have shown potent inhibitory effects on multiple tumors, including hepatocellular carcinoma. In this review, we summarize the pathological mechanisms of MDSCs and their clinical significance as prognostic and predictive biomarkers for HCC patients, and we provide the latest progress of MDSCs-targeting treatment in HCC.

Abstract

One of the major challenges in hepatocellular carcinoma (HCC) treatment is drug resistance and low responsiveness to systemic therapies, partly due to insufficient T cell infiltration. Myeloid-derived suppressor cells (MDSCs) are immature marrow-derived cell populations with heterogeneity and immunosuppression characteristics and are essential components of the suppressive tumor immune microenvironment (TIME). Increasing evidence has demonstrated that MDSCs are indispensable contributing factors to HCC development in a T cell-dependent or non-dependent manner. Clinically, the frequency of MDSCs is firmly linked to HCC clinical outcomes and the effectiveness of immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs). Furthermore, MDSCs can also be used as prognostic and predictive biomarkers for patients with HCC. Therefore, treatments reprograming MDSCs may offer potential therapeutic opportunities in HCC. Here, we recapitulated the dynamic relevance of MDSCs in the initiation and development of HCC and paid special attention to the effect of MDSCs on T cells infiltration in HCC. Finally, we pointed out the potential therapeutic effect of targeting MDSCs alone or in combination, hoping to provide new insights into HCC treatment.

BAP1 and YY1 regulate expression of death receptors in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive, and incurable cancer arising from the mesothelial lining of the pleura, with few available treatment options. We recently reported that loss of function of the nuclear deubiquitinase BRCA1-associated protein 1 (BAP1), a frequent event in MPM, is associated with sensitivity to tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)–mediated apoptosis. As a potential underlying mechanism, here we report that BAP1 negatively regulates the expression of TRAIL receptors: death receptor 4 (DR4) and death receptor 5 (DR5). Using tissue microarrays of tumor samples from MPM patients, we found a strong inverse correlation between BAP1 and TRAIL receptor expression. BAP1 knockdown increased DR4 and DR5 expression, whereas overexpression of BAP1 had the opposite effect. Reporter assays confirmed wt-BAP1, but not catalytically inactive BAP1 mutant, reduced promoter activities of DR4 and DR5, suggesting deubiquitinase activity is required for the regulation of gene expression. Co-immunoprecipitation studies demonstrated direct binding of BAP1 to the transcription factor Ying Yang 1 (YY1), and chromatin immunoprecipitation assays revealed BAP1 and YY1 to be enriched in the promoter regions of DR4 and DR5. Knockdown of YY1 also increased DR4 and DR5 expression and sensitivity to TRAIL. These results suggest that BAP1 and YY1 cooperatively repress transcription of TRAIL receptors. Our finding that BAP1 directly regulates the extrinsic apoptotic pathway will provide new insights into the role of BAP1 in the development of MPM and other cancers with frequent BAP1 mutations.

The Biological and Biomechanical Role of Transglutaminase-2 in the Tumour Microenvironment

Transglutaminase-2 (TG2) is the most highly and ubiquitously expressed member of the transglutaminase enzyme family and is primarily involved in protein cross-linking. TG2 has been implicated in the development and progression of numerous cancers, with a direct role in multiple cellular processes and pathways linked to apoptosis, chemoresistance, epithelial-mesenchymal transition, and stem cell phenotype. The tumour microenvironment (TME) is critical in the formation, progression, and eventual metastasis of cancer, and increasing evidence points to a role for TG2 in matrix remodelling, modulation of biomechanical properties, cell adhesion, motility, and invasion. There is growing interest in targeting the TME therapeutically in response to advances in the understanding of its critical role in disease progression, and a number of approaches targeting biophysical properties and biomechanical signalling are beginning to show clinical promise. In this review we aim to highlight the wide array of processes in which TG2 influences the TME, focussing on its potential role in the dynamic tissue remodelling and biomechanical events increasingly linked to invasive and aggressive behaviour. Drug development efforts have yielded a range of TG2 inhibitors, and ongoing clinical trials may inform strategies for targeting the biomolecular and biomechanical function of TG2 in the TME.

Neural Stem Cell-Based Therapies and Glioblastoma Management: Current Evidence and Clinical Challenges

Gliomas, which account for nearly a quarter of all primary CNS tumors, present significant contemporary therapeutic challenges, particularly the highest-grade variant (glioblastoma multiforme), which has an especially poor prognosis. These difficulties are due to the tumor's aggressiveness and the adverse effects of radio/chemotherapy on the brain. Stem cell therapy is an exciting area of research being explored for several medical issues. Neural stem cells, normally present in the subventricular zone and the hippocampus, preferentially migrate to tumor masses. Thus, they have two main advantages: They can minimize the side effects associated with systemic radio/chemotherapy while simultaneously maximizing drug delivery to the tumor site. Another feature of stem cell therapy is the variety of treatment approaches it allows. Stem cells can be genetically engineered into expressing a wide variety of immunomodulatory substances that can inhibit tumor growth. They can also be used as delivery vehicles for oncolytic viral vectors, which can then be used to combat the tumorous mass. An alternative approach would be to combine stem cells with prodrugs, which can subsequently convert them into the active form upon migration to the tumor mass. As with any therapeutic modality still in its infancy, much of the research regarding their use is primarily based upon knowledge gained from animal studies, and a number of ongoing clinical trials are currently investigating their effectiveness in humans. The aim of this review is to highlight the current state of stem cell therapy in the treatment of gliomas, exploring the different mechanistic approaches, clinical applicability, and the existing limitations.

The Role of Epigallocatechin-3-Gallate in Autophagy and Endoplasmic Reticulum Stress (ERS)-Induced Apoptosis of Human Diseases

Tea containing abundant catechins is a popular non-alcoholic beverage worldwide. Epigallocatechin-3-gallate (EGCG) is the predominately active substance in catechins, exhibiting a wide range of functional properties including cancer suppression, neuroprotective, metabolic regulation, cardiovascular protection, stress adjustment, and antioxidant in various diseases. Autophagy, a basic cell function, participates in various physiological processes which include clearing away abnormally folded proteins and damaged organelles, and regulating growth. EGCG not only regulates autophagy via increasing Beclin-1 expression and reactive oxygen species generation, but also causing LC3 transition and decreasing p62 expression. EGCG-induced autophagy is involved in the occurrence and development of many human diseases, including cancer, neurological diseases, diabetes, cardiovascular diseases, and injury. Apoptosis is a common cell function in biology and is induced by endoplasmic reticulum stress (ERS) as a cellular stress response which is caused by various internal and external factors. ERS-induced apoptosis of EGCG influences cell survival and death in various diseases via regulating IRE1, ATF6, and PERK signaling pathways, and activating GRP78 and caspase proteins. The present manuscript reviews that the effect of EGCG in autophagy and ERS-induced apoptosis of human diseases.

Ischemic Preconditioning Upregulates Decoy Receptors to Protect SH-SY5Y Cells from OGD Induced Cellular Damage by Inhibiting TRAIL Pathway and Agitating PI3K/Akt Pathway

As ischemic preconditioning (IPC) represents a potential therapy against cerebral ischemia, the purpose of the present study is to explore the molecular mechanisms of ischemic preconditioning induced cerebral protective effect. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor superfamily, which induces apoptosis through binding to its death receptors (DR4 and DR5). When TRAIL binds to decoy receptors (DcR1 and DcR2), as DcRs lack intact cytoplasmic death domain, TRAIL fails to induce neuronal apoptosis. In the present study, we demonstrated that ischemic preconditioning upregulated DcR1 and DcR2, which subsequently inhibited oxygen glucose deprivation-induced cellular apoptosis. Then, we investigated the protective molecular mechanism of DcRs after ischemic preconditioning treatment. Results showed that DcR1 could competitively bind to TRAIL and partially inhibit TRAIL-induced cellular apoptosis. On the other hand, DcR2 could disturb DRs-associated death-inducing signaling complex formation (DISC), which further inhibited capase-8 activation. Besides, we also found that ischemic preconditioning activated IPC-induced Akt phosphorylation via regulating DcR2 level. Thus, ischemic preconditioning upregulated decoy receptors, which protected cells from oxygen glucose deprivation-induced cellular damage by inhibiting TRAIL-induced apoptosis and agitating PI3K/Akt pathway. Our data complemented the knowledge of neuroprotective mechanism of ischemic preconditioning and provided new evidence for supporting its clinical application.

CUDC-907 enhances TRAIL-induced apoptosis through upregulation of DR5 in breast cancer cells

CUDC-907 is a novel dual-acting inhibitor of phosphoinositide 3-kinase (PI3K) and histone deacetylase (HDAC). In this study, we aimed to explore the anticancer effects of CUDC-907 on human breast cancer cells. Our results showed that CUDC-907 effectively inhibited breast cancer cell proliferation. Flow cytometry analysis revealed that CUDC-907 induced cell cycle arrest and apoptosis in breast cancer cells. The combined treatment of CUDC-907 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resulted in a marked increase in apoptosis and cleavage of caspase-8, -9 and poly (ADP-ribose) polymerase (PARP) in breast cancer cells. CUDC-907 enhanced expressions of death receptor 5 (DR5), reduced the levels of anti-apoptotic molecules XIAP, Bcl-2 and Bcl-xL. Knockdown of DR5 abrogated apoptosis induced by the combination of CUDC-907 and TRAIL in breast cancer cells. CUDC-907 increased the phosphorylation of JNK and p38 MAPK. JNK inhibitor pretreatment attenuated CUDC-907-induced upregulation of DR5. In summary, CUDC-907 shows potent cytotoxicity against breast cancer cells and facilitates TRAIL-mediated apoptosis through DR5 upregulation. The combination of CUDC-907 and TRAIL may be a promising therapeutic approach in the treatment of breast cancer.

Changes in the Concentration of Markers Participating in the Regulation of the Apoptosis Receptor Pathway Involving Soluble Tumour Necrosis Factor Ligand inducing Apoptosis (sTRAIL) and Osteoprotegerin (OPG) in the Serum of Women with Ovarian Cancer-Participation in Pathogenesis or a Possible Clinical Use?

Due to the ability to selectively induce apoptosis in cancer cells, the most interesting target for clinical research is the tumour necrosis factor ligand inducing apoptosis (TRAIL), which binds specific receptors, including osteoprotegerin (OPG). The aim of the study was to analyse the concentration of soluble TRAIL (sTRAIL) and OPG in the serum of women with serous or mucinous ovarian cancer, taking into account different levels of cancer histological differentiation. The group included 97 women with the diagnosed Cystadenocarcinoma papillare serosum IIIc and Cystadenocarcinoma mucinosum IIIc. Concentrations of parameters were measured by ELISA. Analysis of the obtained results showed a statistically significantly higher concentration of sTRAIL and OPG in the serum of women with ovarian serous and mucinous cancer compared to the control group (p < 0.0001). Statistical significance was found between sTRAIL and OPG concentration in G1 and G3 serous cancer (p < 0.01) and in OPG mucinous cancer between G1 and G3 (p < 0.01) and G2 and G3 (p < 0.01). An important role in the pathogenesis of ovarian cancer is played by disorders of the apoptosis process involving the sTRAIL/OPG system, which are associated with the histological type and the degree of histological differentiation of the tumour. Determining the concentration of tested parameters in combination with other markers may be useful in the future in the diagnosis of ovarian cancer, but that requires further research.

Assessing the Functional Relevance of Variants in the IKAROS Family Zinc Finger Protein 1 (IKZF1) in a Cohort of Patients With Primary Immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency. Patients with CVID are prone to recurrent bacterial infection due to the failure of adequate immunoglobulin production. Monogenetic defects have been identified in ~25% of CVID patients. Recently, mutations in IKZF1, encoding the zinc-finger transcription factor IKAROS which is broadly expressed in hematopoietic cells, have been associated with a CVID-like phenotype. Herein we describe 11 patients with heterozygous IKZF1 variants from eight different families with autosomal dominant CVID and two siblings with an IKZF1 variant presenting with inflammatory bowel disease (IBD). This study shows that mutations affecting the DNA binding domain of IKAROS can impair the interaction with the target DNA sequence thereby preventing heterochromatin and pericentromeric localization (HC-PC) of the protein. Our results also indicate an impairment of pericentromeric localization of IKAROS by overexpression of a truncated variant, caused by an immature stop codon in IKZF1. We also describe an additional variant in TNFSF10, encoding Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL), additionally presented in individuals of Family A. Our results indicate that this variant may impair the TRAIL-induced apoptosis in target cell lines and prohibit the NFκB activation by TRAIL and may act as a modifier in Family A.

Comparative study of interruption of signaling pathways in lung epithelial cell by two different Mycobacterium tuberculosis lineages

Alveolar epithelial cell (AEC) provides a replication niche for Mycobacterium tuberculosis. Based on the role of AEC in M. tuberculosis pathogenesis and existence of genetic diversity within this bacterium, we investigated interactions between AEC II and two different M. tuberculosis lineages. We have compared the transcriptome and cytokines/chemokines levels of A549 infected by M. tuberculosis lineage three and four using qRT-PCR and ELISA arrays, respectively. We showed different M.  tuberculosis strains induced changes in different effectors that involved in TLRs and NF-κB signaling pathways. We observed different reaction of the studied lineages specifically in pathogenesis, immune evasion mechanism, IL-12/IFN-γ axis, and autophagy. Similar behavior was detected in regarding to apoptosis, necroptosis, anti-inflammatory responses, and canonical inflammasome. Our findings contribute to elucidate more details in pathogenesis, immune evasion strategies, novel target and druggable pathway for therapeutic intervention, and host directed therapy in tuberculosis infection. Also, different M.  tuberculosis lineages-dependent host-pathogen interactions suggested using only one strain for this kind of research will be controversial.

MEDI3039, a novel highly potent tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) receptor 2 agonist, causes regression of orthotopic tumors and inhibits outgrowth of metastatic triple-negative breast cancer

Background

TNF-related apoptosis-inducing ligand (TRAIL) receptor agonists are attractive anti-tumor agents because of their capability to induce apoptosis in cancer cells by activating death receptors (DR) 4 and 5 with little toxicity against normal cells. Despite an attractive mechanism of action, previous clinical efforts to use TRAIL receptor agonists have been unsuccessful. In this study, we examined MEDI3039, a highly potent multivalent DR5 agonist, in breast cancer cell lines and in vivo models.

Methods

As in vitro model systems, we used 19 breast cancer cell lines that are categorized into four subtypes: ER+, HER2 amplified, basal A (triple-negative breast cancer) TNBC, and basal B TNBC. Cell viability was analyzed by MTS and RealTime live/dead assays. As in vivo model systems, MDA-MB231T orthotopic primary tumor growth in the mammary fat pad (MFP) and two experimental lung metastasis models were used. The effect of MEDI3039 on MFP tumors was assessed with immunohistochemical analysis. Lung metastases were analyzed with Bouin’s and H&E staining.

Results

MEDI3039 killed multiple breast cancer cell lines, but the sensitivity varied among different subtypes. Sensitivity was basal B TNBC >> basal A TNBC > HER2 amplified > ER+ (average IC₅₀ = 1.4, 203, 314, 403 pM, respectively). While the pattern of relative sensitivity was similar to GST-TRAIL in most cell lines, MEDI3039 was at least two orders of magnitude more potent compared with GST-TRAIL. In the MFP model, weekly treatment with 0.1 or 0.3 mg/kg MEDI3039 for 5 weeks inhibited tumor growth by 99.05% or 100% (median), respectively, compared with the control group, and extended animal survival (p = 0.08 or p = 0.0032 at 0.1 or 0.3 mg/kg, respectively). MEDI3039-induced caspase activation was confirmed in tumors grown in MFP (p < 0.05). In an experimental pulmonary metastasis model, MEDI3039 significantly suppressed outgrowth of surface (p < 0.0001) and microscopic metastases (p < 0.05). In an established lung metastasis model, MEDI3039 significantly inhibited growth of metastases (p < 0.01 in surface [> 4 mm], p < 0.01 in tumor percentage) and extended animal survival (p < 0.0001).

Conclusion

MEDI3039 is a potent DR5 agonist in breast cancer cells in vitro and in vivo and has potential as a cancer drug in breast cancer patients, especially those with basal B TNBC.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1116-1) contains supplementary material, which is available to authorized users.

The TNF Family of Ligands and Receptors: Communication Modules in the Immune System and Beyond

The tumor necrosis factor (TNF) and TNF receptor (TNFR) superfamilies (TNFSF/TNFRSF) include 19 ligands and 29 receptors that play important roles in the modulation of cellular functions. The communication pathways mediated by TNFSF/TNFRSF are essential for numerous developmental, homeostatic, and stimulus-responsive processes in vivo. TNFSF/TNFRSF members regulate cellular differentiation, survival, and programmed death, but their most critical functions pertain to the immune system. Both innate and adaptive immune cells are controlled by TNFSF/TNFRSF members in a manner that is crucial for the coordination of various mechanisms driving either co-stimulation or co-inhibition of the immune response. Dysregulation of these same signaling pathways has been implicated in inflammatory and autoimmune diseases, highlighting the importance of their tight regulation. Investigation of the control of TNFSF/TNFRSF activities has led to the development of therapeutics with the potential to reduce chronic inflammation or promote anti-tumor immunity. The study of TNFSF/TNFRSF proteins has exploded over the last 30 yr, but there remains a need to better understand the fundamental mechanisms underlying the molecular pathways they mediate to design more effective anti-inflammatory and anti-cancer therapies.

Interaction between N-cadherin and decoy receptor-2 regulates apoptosis in head and neck cancer

N-cadherin is a neural cell adhesion molecule that aberrantly occurs in head and neck cancers to promote cancer cell growth. However, the underlying mechanisms remain unclear. Here we report that N-cadherin increases cancer cell growth by inhibiting apoptosis. Apoptosis eliminates old, unnecessary, and unhealthy cells. However, tumor cells have the ability of avoiding apoptosis that increases cancer cell growth. Recent studies have found that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in tumor cells by reacting with four distinct cell surface receptors: TRAIL-R1 (DR-4), TRAIL-R2 (DR-5), TRAIL-R3 (DcR-1), and TRAIL-R4 (DcR-2). Among these TRAIL receptors, the death receptors DR-4 and DR-5 transmit apoptotic signals owing to the death domain in the intracellular portion. Conversely, the decoy receptors DcR-1 and DcR-2 lack a complete intracellular portion, so neither can transmit apoptotic signals. DcR-1 or DcR-2 overexpression suppresses TRAIL-induced apoptosis.

In this study, N-cadherin overexpression increased DcR-2 expression and decreased DR-5 expression. In contrast, knockdown of N-cadherin expression upregulated DR-5 expression and downregulated DcR-2 expression. A significantly positive relationship between N-cadherin and DcR-2 expression was also found in HNSCC specimens. Those specimens with a lower apoptotic index showed a higher expression of N-cadherin and/or DcR-2. In addition, we demonstrated that N-cadherin interacts directly with DcR-2. Notably, DcR-2 induces cancer cell survival through the cleavage of caspases and PARP by activating MAPK/ERK pathway and suppressing NF-kB/ p65 phosphorylation, which has a very important role in resistance to chemotherapy.

Synergistic effect of TRAIL and irradiation in elimination of glioblastoma stem-like cells

Glioblastoma multiforme (GBM) is the most common malignancy in central nervous system. A small subpopulation of GBM cells known as GBM stem-like cells (GSLCs) were supposed to be the most malignant cells among GBM cells as they are resistant to multiple therapies including radiotherapy. In this study, we set up two GSLCs cell lines from the two parental U87 and U251 glioma cell lines, and studied the expression of apoptosis-related genes alteration in GSLCs before and after irradiation. We found that one of the receptors of TNF-related apoptosis-inducing ligand (TRAIL), DR5, was dramatically up-regulated in GSLCs after irradiation (IR). Although GSLCs are resistant to both TRAIL and radiation treatment alone, the combined treatment with TRAIL and irradiation achieved maximum killing effect of GSLCs due to inducing the expression of DR5 and inhibiting the expression of cFLIP. Therefore, TRAIL and IR combined treatment would be a simple but practical therapeutic strategy for clinical application.

ONC201 kills breast cancer cells in vitro by targeting mitochondria

We report a novel mechanism of action of ONC201 as a mitochondria-targeting drug in cancer cells. ONC201 was originally identified as a small molecule that induces transcription of TNF-related apoptosis-inducing ligand (TRAIL) and subsequently kills cancer cells by activating TRAIL death receptors. In this study, we examined ONC201 toxicity on multiple human breast and endometrial cancer cell lines. ONC201 attenuated cell viability in all cancer cell lines tested. Unexpectedly, ONC201 toxicity was not dependent on either TRAIL receptors nor caspases. Time-lapse live cell imaging revealed that ONC201 induces cell membrane ballooning followed by rupture, distinct from the morphology of cells undergoing apoptosis. Further investigation found that ONC201 induces phosphorylation of AMP-dependent kinase and ATP loss. Cytotoxicity and ATP depletion were significantly enhanced in the absence of glucose, suggesting that ONC201 targets mitochondrial respiration. Further analysis indicated that ONC201 indirectly inhibits mitochondrial respiration. Confocal and electron microscopic analysis demonstrated that ONC201 triggers mitochondrial structural damage and functional impairment. Moreover, ONC201 decreased mitochondrial DNA (mtDNA). RNAseq analysis revealed that ONC201 suppresses expression of multiple mtDNA-encoded genes and nuclear-encoded mitochondrial genes involved in oxidative phosphorylation and other mitochondrial functions. Importantly, fumarate hydratase deficient cancer cells and multiple cancer cell lines with reduced amounts of mtDNA were resistant to ONC201. These results indicate that cells not dependent on mitochondrial respiration are ONC201-resistant. Our data demonstrate that ONC201 kills cancer cells by disrupting mitochondrial function and further suggests that cancer cells that are dependent on glycolysis will be resistant to ONC201.

Ublituximab for the treatment of CD20 positive B-cell malignancies

INTRODUCTION

Non-Hodgkin lymphoma (NHL) is the most common adult hematologic malignancy. Conventional methods of treatment are chemotherapy and radiation, which were associated with toxicities and lack of specificity. Potential cell surface targets for treatment of B-cell NHL (B-NHL) include CD19, CD20, and CD22 which are highly expressed on malignant B-cells. The development of monoclonal antibody (mAb) therapy directed against CD20 had the most clinical impact in the treatment of B-NHL. Early clinical trials with rituximab (RTX), the first chimeric mAb against CD20, showed efficacy and minimal toxicities. RTX was later approved as first line in combination with CHOP chemotherapy for Diffuse Large B-NHL (DLBCL). The emergence of resistance to RTX prompted the development of the next-generation of mAbs targeting CD20 (e.g. obinituzumab, ofatumumab), and includes ublituximab (Ub), with higher complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) against malignant B-cells. Areas covered: Herein, we discuss clinical trials of Ub, highlighting efficacy, tolerability and an expert opinion on drug development in B-NHL. A pubmed search was conducted to evaluate all Ub clinical trials. Expert opinion: Ub demonstrated efficacy in patients with high-risk CLL and B-NHL in both first line, subsequent lines, and in rituximab refractory patients.

Inhibition of never in mitosis A (NIMA)-related kinase-4 reduces survivin expression and sensitizes cancer cells to TRAIL-induced cell death

The tumor necrosis factor-related apoptosis inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells. However, many tumors are resistant to TRAIL-induced apoptosis, and resistance mechanisms are not fully understood. To identify novel regulatory molecules of TRAIL resistance, we screened a siRNA library targeting the human kinome, and NEK4 (NIMA-related kinase-4) was identified. Knockdown of NEK4 sensitized TRAIL-resistant cancer cells and in vivo xenografts to cell death. In contrast, over expression of NEK4 suppressed TRAIL-induced cell death in TRAIL-sensitive cancer cells. In addition, loss of NEK4 resulted in decrease of the anti-apoptotic protein survivin, but an increase in apoptotic cell death. Interestingly, NEK4 was highly upregulated in tumor tissues derived from patients with lung cancer and colon cancer. These results suggest that inhibition of NEK4 sensitizes cancer cells to TRAIL-induced apoptosis by regulation of survivin expression.

Activation of autophagic flux by epigallocatechin gallate mitigates TRAIL-induced tumor cell apoptosis via down-regulation of death receptors

Epigallocatechin gallate (EGCG) is a major polyphenol in green tea. Recent studies have reported that EGCG can inhibit TRAIL-induced apoptosis and activate autophagic flux in cancer cells. However, the mechanism behind these processes is unclear. The present study found that EGCG prevents tumor cell death by antagonizing the TRAIL pathway and activating autophagy flux. Our results indicate that EGCG dose-dependently inhibits TRAIL-induced apoptosis and decreases the binding of death receptor 4 and 5 (DR4 and 5) to TRAIL. In addition, EGCG activates autophagy flux, which is involved in the inhibition of TRAIL cell death. We confirmed that the protective effect of EGCG can be reversed using genetic and pharmacological tools through re-sensitization to TRAIL. The inhibition of autophagy flux affects not only the re-sensitization of tumor cells to TRAIL, but also the restoration of death receptor proteins. This study demonstrates that EGCG inhibits TRAIL-induced apoptosis through the manipulation of autophagic flux and subsequent decrease in number of death receptors. On the basis of these results, we suggest further consideration of the use of autophagy activators such as EGCG in combination anti-tumor therapy with TRAIL.

BIX-01294 sensitizes renal cancer Caki cells to TRAIL-induced apoptosis through downregulation of survivin expression and upregulation of DR5 expression

BIX-01294 (BIX), a G9a histone methyltransferase inhibitor, has been reported for its anti-proliferative and anticancer activities against various cancer cell lines. In this study, we investigated whether BIX could sensitize TRAIL-mediated apoptosis in various cancer cells. Combined treatment with BIX and TRAIL markedly induced apoptosis in human renal carcinoma (Caki, ACHN, and A498), breast carcinoma (MCF-7), and lung carcinoma (A549) cells. In contrast, BIX and TRAIL co-treatment did not induce apoptosis in normal cells, specifically mouse kidney cell (TCMK-1) and human skin fibroblast (HSF). BIX downregulated protein expression levels of XIAP and survivin at the post-translational level. Overexpression of survivin markedly blocked combined BIX and TRAIL treatment-induced apoptosis, but XIAP had no effect. Furthermore, BIX induced upregulation of DR5 expression at the transcriptional levels, and knockdown of DR5 expression using small interfering RNAs (siRNAs) markedly attenuated BIX and TRAIL-induced apoptosis. Interestingly, siRNA-mediated G9a histone methyltransferase knockdown also enhanced TRAIL-induced apoptosis in Caki cells. However, knockdown of G9a did not change expression levels of XIAP, survivin, and DR5. Therefore, BIX-mediated TRAIL sensitization was independent of histone methyltransferase G9a activity. Taken together, these results suggest that BIX facilitates TRAIL-mediated apoptosis via downregulation of survivin and upregulation of DR5 expression in renal carcinoma Caki cells.

▶ BIX facilitates TRAIL-mediated apoptosis in human renal carcinoma Caki cells.

▶ Downregulation of survivin contributes to BIX plus TRAIL-induced apoptosis.

▶ Upregulation of DR5 is involved in BIX plus TRAIL-mediated apoptosis.

▶ BIX-mediated TRAIL sensitization is independent of ROS production.

YM155 sensitizes TRAIL-induced apoptosis through cathepsin S-dependent down-regulation of Mcl-1 and NF-κB-mediated down-regulation of c-FLIP expression in human renal carcinoma Caki cells

YM155, a small-molecule survivin inhibitor, has been reported for its anti-cancer activity in various cancer cells. In this study, we investigated the effect of YM155 to enhance TRAIL-mediated apoptosis in human renal carcinoma cells. We found that YM155 alone had no effect on apoptosis, however, combined treatment with YM155 and TRAIL markedly induced apoptosis in human renal carcinoma cells (Caki, ACHN, and A498), breast cancer cells (MDA-MB231), and glioma cells (U251MG), but not normal cells [mesangial cell (MC) and human skin fibroblast (HSF)]. YM155 induced down-regulation of Mcl-1 expression at the post-translational levels, and the overexpression of Mcl-1 markedly inhibited YM155 plus TRAIL-induced apoptosis. Furthermore, YM155 induced down-regulation of c-FLIP mRNA expression through inhibition of NF-κB transcriptional activity. Ectopic expression of c-FLIP markedly blocked YM155-induced TRAIL sensitization. Taken together, our results suggested that YM155 sensitizes TRAIL-mediated apoptosis via down-regulation of Mcl-1 and c-FLIP expression in renal carcinoma Caki cells.

Apigenin promotes TRAIL-mediated apoptosis regardless of ROS generation

Apigenin is a bioactive flavone in several herbs including parsley, thyme, and peppermint. Apigenin possesses anti-cancer and anti-inflammatory properties; however, whether apigenin enhances TRAIL-mediated apoptosis in cancer cells is unknown. In the current study, we found that apigenin enhanced TRAIL-induced apoptosis by promoting caspase activation and death receptor 5 (DR5) expression and a chimeric antibody against DR5 completely blocked the apoptosis. Apigenin also upregulated reactive oxygen species (ROS) generation; however, intriguingly, ROS inhibitors, glutathione (GSH) or N-acetyl-l-cysteine (NAC), moderately increased apigenin/TRAIL-induced apoptosis. Additional results showed that an autophagy inducer, rapamycin, enhanced apigenin/TRAIL-mediated apoptosis by a slight increase of ROS generation. Accordingly, NAC and GSH rather decreased apigenin-induced autophagy formation, suggesting that apigenin-induced ROS generation increased autophagy formation. However, autophagy inhibitors, bafilomycin (BAF) and 3-methyladenine (3-MA), showed different result in apigenin/TRAIL-mediated apoptosis without ROS generation. 3-MA upregulated the apoptosis but remained ROS levels; however, no changes on apoptosis and ROS generation were observed by BAF treatment. Taken together, these findings reveal that apigenin enhances TRAIL-induced apoptosis by activating apoptotic caspases by upregulating DR5 expression regardless of ROS generation, which may be a promising strategy for an adjuvant of TRAIL.

A systematic review of molecular responses to cancer therapy in normal human mucosa

OBJECTIVE

Cancer therapy-induced inflammation of oral and gastrointestinal mucosae affects patients nonuniformly. Preventive strategies are limited; no biomarker exists for pretreatment identification of patients likely to be severely affected. Animal models are preferred for studying molecular responses in mucosae during chemotherapy, but translation into clinical practice is difficult. We performed a systematic review to retrieve articles that described molecular changes in human mucosae during cancer therapy.

STUDY DESIGN

We searched MEDLINE and Ovid Embase searches for studies reported in the English language literature from January 1990 to November 2016 and studies referenced in selected articles, which analyzed mucosae from patients at risk of developing mucositis during cancer therapy. Two authors extracted data according to predefined data fields, including study quality indicators.

RESULTS

We identified 17 human studies on chemotherapy (n = 9) and radiotherapy (n = 8), but no studies on targeted therapy. Studies were heterogeneous with regard to patient cohorts, analysis methods, cancer treatments, biopsy timings, and correlations to clinical mucositis. Consequently, a meta-analysis was not feasible.

CONCLUSIONS

Few human studies described the molecular responses of the normal mucosa to cancer therapy. Studies were heterogeneous and had sparse correlations to clinical mucositis. We proposed a model for acquiring data on treatment- and disease-specific phenotypes and transcriptomes for predictive or preventive initiatives.

TRAF2 is a Valuable Prognostic Biomarker in Patients with Prostate Cancer

BACKGROUND TRAF2 exerts important functions in regulating the development and progression of cancer. The aim of this study is to investigate whether TRAF2 is a valuable prognostic biomarker and to determine if it regulates TRAIL-induced apoptosis in prostate cancer. MATERIAL AND METHODS Microarray gene expression data from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were used to determine TRAF2 expression in prostate cancer. TRAF2 expression in prostate cancer was further investigated by immunohistochemistry assay. Kaplan-Meier curves and log-rank test were used to assess the recurrence-free rate. Cox regression was used to analyze prognostic factors. Effects of TRAF2 on regulating TRAIL-induced apoptosis in DU-145 cells were further investigated. RESULTS We found that TRAF2 was significantly upregulated in prostate cancer compared with normal prostate samples (P<0.001). In addition, compared with primary prostate cancer, TRAF2 was upregulated in metastatic prostate cancer (P=0.006). Furthermore, our results showed that high expression of TRAF2 was significantly associated with tumor stage of prostate cancer (P=0.035). TRAF2 high expression was associated with poorer recurrence-free survival in prostate cancer patients (P=0.013). TRAF2 was found to be a valuable independent prognostic factor for predicting recurrence-free survival (P=0.026). In addition, the present results indicate that TRAF2 affects TRAIL-induced apoptosis in prostate cancer DU-145 cells via regulating cleaved Caspase-8 and c-Flip expression. CONCLUSIONS TRAF2 could be a novel prognostic biomarker for predicting recurrence-free survival in patients with prostate cancer, which might be associated with the effects of TRAF2 in regulating TRAIL-induced apoptosis in prostate cancer cells via c-Flip/Caspase-8 signalling.

Assessment of concentrations of sTRAIL ligand and its receptors sTRAIL-R1 and sTRAIL-R2 - markers monitoring the course of the extrinsic pathway of apoptosis induction: potential application in ovarian cancer diagnostics

INTRODUCTION

TNF-related apoptosis-inducing ligand (TRAIL) together with its receptors are involved in activation of the extrinsic pathway of apoptosis. Due to the special role of the apoptosis pathway in pathogenesis of ovarian cancers, the aim of the study was to assess concentrations of sTRAIL, sTRAIL-R1 and sTRAIL-R2 in serum of affected women.

MATERIAL AND METHODS

The study group included 85 women with diagnosed ovarian tumors: 35 women with ovarian serous cystadenoma, 15 women with ovarian teratoma and 35 women with serous cystadenocarcinoma. The control group consisted of 30 healthy women. Concentrations of studied parameters were measured by ELISA methods.

RESULTS

Serum levels of all studied parameters were higher in serum of women with ovarian tumors than in the controls, but their concentrations varied depending on the clinical diagnosis. The highest concentration of TRAIL was found in serum of women with ovarian cancer, the highest sTRAIL-R1 level in serum of women with ovarian mature teratoma, and the highest sTRAIL-R2 level in serum of women with ovarian serous cystadenoma.

CONCLUSIONS

The state of immunosuppression accompanying neoplastic disease depends on the extrinsic pathway of apoptosis induction in the TRAIL/TRAIL-R system. Determination of TRAIL-R1 and TRAIL-R2 levels may prove to be useful in ovarian tumor differential diagnostics, which requires further research.

Altered expression of TRAIL on mouse T cells via ERK phosphorylation by Rhodiola rosea L. and its marker compounds

Rhodiola rosea L. extracts have shown neuroprotective, anti-fatigue, anti-inflammatory and anti-tumor properties. However, the studies on their effect on T cell function are rather scarce. We examined the potential of R. rosea extract and its major constituents - salidroside, rosarin, rosavin and rosin to alter cell growth of human Jurkat T cells, apoptosis of splenic mouse CD3 T cells and expression of the surface markers and phosphorylation of extracellular signal-regulated kinase (ERK). The initial screening for cell viability in Jurkat T cells and for apoptosis of mouse T cells showed the strongest activity for rosavin and rosarin. Rosarin and rosavin did not alter significantly the dynamic of CD69 expression upon stimulation, but altered TNF-related apoptosis-inducing ligand (TRAIL) expression. Rosavin inhibited TRAIL up-regulation, while rosarin showed an opposite effect. Indeed, rosarin increased the frequencies of CD3⁺TRAIL⁺ T cells and the fold inhibition of ERK phosphorylation. Our data showed that different effects of rosarin and rosavin on TRAIL expression can involve distinct action on ERK signaling and hence highlighted their potential to manipulate TRAIL as a tool to rescue the resistance to apoptosis in autoimmune diseases and cancer.

Selective Targeting of Myeloid-Derived Suppressor Cells in Cancer Patients Using DS-8273a, an Agonistic TRAIL-R2 Antibody

Purpose: Myeloid-derived suppressor cells (MDSC) are one of the major contributors to immune suppression in cancer. We recently have demonstrated in preclinical study that MDSCs are sensitive to TRAIL receptor 2 (TRAIL-R2) agonist. The goal of this study was to clinically test the hypothesis that targeting TRAIL-R2 can selectively eliminate MDSCs.Experimental Design: The TRAIL-R2 agonistic antibody (DS-8273a) has been tested in 16 patients with advanced cancers enrolled in a phase I trial. The antibody (24 mg/kg) was administered intravenously once every 3 weeks till disease progression, unacceptable toxicities, or withdrawal of consent. The safety and the presence of various populations of myeloid and lymphoid cells in peripheral blood and tumor tissues were evaluated.Results: The treatment was well tolerated with only mild to moderate adverse events attributable to the study drug. Treatment with DS-8273a resulted in reduction of the elevated numbers of MDSCs in the peripheral blood of most patients to the levels observed in healthy volunteers. However, in several patients, MDSCs rebounded back to the pretreatment level by day 42. In contrast, DS-8273a did not affect the number of neutrophils, monocytes, and other populations of myeloid and lymphoid cells. Decrease in MDSCs inversely correlated with the length of progression-free survival. In tumors, DS-8273a treatment resulted in a decrease of MDSCs in 50% of the patients who were able to provide pre- and on-treatment biopsies.Conclusions: Targeting TRAIL-R2 resulted in elimination of different populations of MDSCs without affecting mature myeloid or lymphoid cells. These data support the use of this antibody in combination immmunotherapy of cancer. Clin Cancer Res; 23(12); 2942-50. ©2016 AACR.

Niacin alleviates TRAIL-mediated colon cancer cell death via autophagy flux activation

Niacin, also known as vitamin B₃ or nicotinamide is a water-soluble vitamin that is present in black beans and rice among other foods. Niacin is well known as an inhibitor of metastasis in human breast carcinoma cells but the effect of niacin treatment on TRAIL-mediated apoptosis is unknown. Here, we show that niacin plays an important role in the regulation of autophagic flux and protects tumor cells against TRAIL-mediated apoptosis. Our results indicated that niacin activated autophagic flux in human colon cancer cells and the autophagic flux activation protected tumor cells from TRAIL-induced dysfunction of mitochondrial membrane potential and tumor cell death. We also demonstrated that ATG5 siRNA and autophagy inhibitor blocked the niacin-mediated inhibition of TRAIL-induced apoptosis. Taken together, our study is the first report demonstrating that niacin inhibits TRAIL-induced apoptosis through activation of autophagic flux in human colon cancer cells. And our results also suggest that autophagy inhibitors including genetic and pharmacological tools may be a successful therapeutics during anticancer therapy using TRAIL.

Targeting miRNAs associated with surface expression of death receptors to modulate TRAIL resistance in breast cancer

Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) is capable of inducing apoptosis upon engagement of its death receptors (DRs) 4 and 5. TRAIL therapy has garnered intense interest as one of the most promising agents for cancer therapy, for its selective induction of tumor-cell apoptosis while low toxicity to most normal cells. However, a variety of breast cancer cell lines could be resistant to TRAIL-induced apoptosis. Absence of DR4 and DR5 on the breast cancer cell surface has been proposed to be critically involved in resistance to TRAIL and its agonistic antibodies. Moreover, endocytosis and autophagy in breast cancer cells could induce TRAIL resistance through downregulation of surface DR4/5. MicroRNAs (miRNAs), as endogenously expressed small non-coding RNAs, function as regulators of gene expression and involve tremendous biological processes including drug resistance. In this review, we highlight recent advances in the functional role of miRNAs in endocytosis and autophagy pathways. This review aims to present that, through regulation of critical molecules involved in autophagy and endocytosis, miRNAs could lead to mislocalization of DR4/5 in breast cancer cells and therefore play an important role in TRAIL-mediated apoptosis and TRAIL resistance.

Carnosic acid attenuates unilateral ureteral obstruction-induced kidney fibrosis via inhibition of Akt-mediated Nox4 expression

Fibrosis represents a common pathway to end-stage renal disease. Transforming growth factor-β (TGF-β) plays a critical role in the progression of kidney fibrosis. In the present study, we explored the effect of carnosic acid (CA) against TGF-β-induced fibroblast activation in vitro and unilateral ureteral obstruction (UUO)-induced kidney fibrosis in vivo. CA attenuated TGF-β-induced up-regulation of profibrogenic proteins, α-smooth muscle actin (α-SMA), collagen I (COLI), fibronectin (FN), and plasminogen activator inhibitor-1 (PAI-1) in kidney fibroblast cells (NRK-49F). CA inhibited TGF-β-induced hydrogen peroxide generation via inhibition of NADPH oxidase 4 (Nox4) expressions. In mice, CA-administration markedly mitigated the UUO-induced interstitial extension, collagen deposition, superoxide anion formation, hydrogen peroxide production, and lipid peroxidation. In addition, CA significantly attenuated the expression of α-SMA, COLI, FN, PAI-1, and Nox4 in UUO-induced kidneys. These results indicated that CA attenuated oxidative stress via inhibition of Nox4 expression in TGF-β-stimulated fibroblasts and UUO operated-kidneys, suggesting that CA may be useful for the treatment of fibrosis-related diseases.

ABC294640, a sphingosine kinase 2 inhibitor, enhances the antitumor effects of TRAIL in non-small cell lung cancer

Evidences suggest that tumor microenvironment may play an important role in cancer drug resistance. Sphingosine kinase 2 (SphK2) is proposed to be the key regulator of sphingolipid signaling. This study is aimed to investigate whether the combination of molecular targeting therapy using a specific inhibitor of SphK2 (ABC294640), with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can enhance the apoptosis of non-small cell lung cancer (NSCLC) cells. Our results revealed that NSCLC cells' sensitivity to TRAIL is correlated with the level of SphK2. Compared with TRAIL alone, the combination therapy enhanced the apoptosis induced by TRAIL, and knockdown of SphK2 by siRNA presented a similar effect. Combination therapy with ABC294640 increased the activity of caspase-3/8 and up-regulated the expression of death receptors (DR). Additional investigations revealed that translocation of DR4/5 to the cell membrane surface was promoted by adding ABC294640. However, expression of anti-apoptosis proteins such as Bcl(-)2 and IAPs was not significantly modified by this SphK2 inhibitor. Overall, this work demonstrates that SphK2 may contribute to the apoptosis resistance in NSCLC, thus indicating a new therapeutic target for resistant NSCLC cells.

TRAIL causes deletions at the HPRT and TK1 loci of clonogenically competent cells

When chemotherapy and radiotherapy are effective, they function by inducing DNA damage in cancerous cells, which respond by undergoing apoptosis. Some adverse effects can result from collateral destruction of non-cancerous cells, via the same mechanism. Therapy-related cancers, a particularly serious adverse effect of anti-cancer treatments, develop due to oncogenic mutations created in non-cancerous cells by the DNA damaging therapies used to eliminate the original cancer. Physiologically achievable concentrations of direct apoptosis inducing anti-cancer drugs that target Bcl-2 and IAP proteins possess negligible mutagenic activity, however death receptor agonists like TRAIL/Apo2L can provoke mutations in surviving cells, probably via caspase-mediated activation of the nuclease CAD. In this study we compared the types of mutations sustained in the HPRT and TK1 loci of clonogenically competent cells following treatment with TRAIL or the alkylating agent ethyl methanesulfonate (EMS). As expected, the loss-of-function mutations in the HPRT or TK1 loci triggered by exposure to EMS were almost all transitions. In contrast, only a minority of the mutations identified in TRAIL-treated clones lacking HPRT or TK1 activity were substitutions. Almost three quarters of the TRAIL-induced mutations were partial or complete deletions of the HPRT or TK1 genes, consistent with sub-lethal TRAIL treatment provoking double strand breaks, which may be mis-repaired by non-homologous end joining (NHEJ). Mis-repair of double-strand breaks following exposure to chemotherapy drugs has been implicated in the pathogenesis of therapy-related cancers. These data suggest that TRAIL too may provoke oncogenic damage to the genomes of surviving cells.

ONC201: Stressing tumors to death

The small molecule ONC201 was identified in a screen for compounds that would induce expression of the gene encoding tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in tumors and thus cause an autocrine- or paracrine-induced death in tumor cells. Two Research Articles in this issue of Science Signaling by Ishizawa et al. and Kline et al. describe how ONC201 can also trigger cytotoxicity by inducing a stress response. The mechanisms of the stress response induced differ between hematological malignancies and solid tumors, highlighting the complexity of ONC201-induced toxicity and raising intriguing issues of tissue-specific pathways activated by the drug.

Therapeutically engineered induced neural stem cells are tumour-homing and inhibit progression of glioblastoma

Transdifferentiation (TD) is a recent advancement in somatic cell reprogramming. The direct conversion of TD eliminates the pluripotent intermediate state to create cells that are ideal for personalized cell therapy. Here we provide evidence that TD-derived induced neural stem cells (iNSCs) are an efficacious therapeutic strategy for brain cancer. We find that iNSCs genetically engineered with optical reporters and tumouricidal gene products retain the capacity to differentiate and induced apoptosis in co-cultured human glioblastoma cells. Time-lapse imaging shows that iNSCs are tumouritropic, homing rapidly to co-cultured glioblastoma cells and migrating extensively to distant tumour foci in the murine brain. Multimodality imaging reveals that iNSC delivery of the anticancer molecule TRAIL decreases the growth of established solid and diffuse patient-derived orthotopic glioblastoma xenografts 230- and 20-fold, respectively, while significantly prolonging the median mouse survival. These findings establish a strategy for creating autologous cell-based therapies to treat patients with aggressive forms of brain cancer.

Neural stem cells have a tropism for glioblastoma. Here the authors employ fibroblasts directly reprogrammed into induced neural stem cells and loaded with cytotoxic molecules to migrate to xenotransplanted brain tumours in mice, achieving tumour shrinkage and prolonged survival.

The Deubiquitinase Inhibitor PR-619 Sensitizes Normal Human Fibroblasts to Tumor Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL)-mediated Cell Death

TNF-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapy that selectively targets cancer cell death while non-malignant cells remain viable. Using a panel of normal human fibroblasts, we characterized molecular differences in human foreskin fibroblasts and WI-38 TRAIL-resistant cells and marginally sensitive MRC-5 cells compared with TRAIL-sensitive human lung and colon cancer cells. We identified decreased caspase-8 protein expression and protein stability in normal fibroblasts compared with cancer cells. Additionally, normal fibroblasts had incomplete TRAIL-induced caspase-8 activation compared with cancer cells. We found that normal fibroblasts lack the ubiquitin modification of caspase-8 required for complete caspase-8 activation. Treatment with the deubiquitinase inhibitor PR-619 increased caspase-8 ubiquitination and caspase-8 enzymatic activity and sensitized normal fibroblasts to TRAIL-mediated apoptosis. Therefore, posttranslational regulation of caspase-8 confers resistance to TRAIL-induced cell death in normal cells through blockade of initiation of the extrinsic cell death pathway.

TRAIL-based therapy in pediatric bone tumors: how to overcome resistance

Osteosarcoma and Ewing's sarcoma, the two most frequent malignant primary tumors preferentially arise in children and young adults, and have a poor prognosis. TRAIL represents a promising therapeutic approach for most cancers but in the case of primary bone tumors, osteosarcoma cell lines are highly resistant to this pro-apoptotic cytokine. In addition, another signaling pathway mediating cell proliferation and migration may be even activated in this subset of resistant cells leading to protumoral effect. Therapeutic perspectives are linked to possibility to overcome TRAIL resistance by combining other drugs with TRAIL or death receptors agonistic antibodies. We hypothesized that the bone microenvironment may provide a favorable niche for TRAIL resistance that might be targeted by new resensitizing agents.

The BET bromodomain inhibitor, JQ1, facilitates c-FLIP degradation and enhances TRAIL-induced apoptosis independent of BRD4 and c-Myc inhibition

Inhibition of BET bromodomains (BRDs) has emerged as a promising cancer therapeutic strategy. Accordingly, inhibitors of BRDs such as JQ1 have been actively developed and some have reached clinical testing. However, the mechanisms by which this group of inhibitors exerts their anticancer activity, including induction of apoptosis, have not been fully elucidated. This report reveals a previously uncovered activity of JQ1 in inducing c-FLIP degradation and enhancing TRAIL-induced apoptosis. JQ1 potently decreased c-FLIP (both long and short forms) levels in multiple cancer cell lines without apparently increasing the expression of DR5 and DR4. Consequently, JQ1, when combined with TRAIL, synergistically induced apoptosis; this enhanced apoptosis-inducing activity could be abolished by enforced expression of ectopic FLIPL or FLIPS. Hence it appears that JQ1 decreases c-FLIP levels, resulting in enhancement of TRAIL-induced apoptosis. Inhibition of proteasome with MG132 prevented JQ1-induced c-FLIP reduction. Moreover, JQ1 decreased c-FLIP stability. Therefore, JQ1 apparently decreases c-FLIP levels through facilitating its proteasomal degradation. Genetic inhibition of either BRD4 or c-Myc by knocking down their expression failed to mimic JQ1 in decreasing c-FLIP and enhancing TRAIL-induced apoptosis, suggesting that JQ1 induces c-FLIP degradation and enhances TRAIL-induced apoptosis independent of BRD4 or c-Myc inhibition. In summary, our findings in this study highlights a novel biological function of JQ1 in modulating apoptosis and warrant further study of the potential treatment of cancer with the JQ1 and TRAIL combination.

ONC201 induces cell death in pediatric non-Hodgkin's lymphoma cells

ONC201/TIC10 is a small molecule initially discovered by its ability to coordinately induce and activate the TRAIL pathway selectively in tumor cells and has recently entered clinical trials in adult advanced cancers. The anti-tumor activity of ONC201 has previously been demonstrated in several preclinical models of cancer, including refractory solid tumors and a transgenic lymphoma mouse model. Based on the need for new safe and effective therapies in pediatric non-Hodgkin's lymphoma (NHL) and the non-toxic preclinical profile of ONC201, we investigated the in vitro efficacy of ONC201 in non-Hodgkin's lymphoma (NHL) cell lines to evaluate its therapeutic potential for this disease. ONC201 caused a dose-dependent reduction in the cell viability of NHL cell lines that resulted from induction of apoptosis. As expected from prior observations, induction of TRAIL and its receptor DR5 was also observed in these cell lines. Furthermore, dual induction of TRAIL and DR5 appeared to drive the observed apoptosis and TRAIL expression was correlated linearly with sub-G1 DNA content, suggesting its potential role as a biomarker of tumor response to ONC201-treated lymphoma cells. We further investigated combinations of ONC201 with approved chemotherapeutic agents used to treat lymphoma. ONC201 exhibited synergy in combination with the anti-metabolic agent cytarabine in vitro, in addition to cooperating with other therapies. Together these findings indicate that ONC201 is an effective TRAIL pathway-inducer as a monoagent that can be combined with chemotherapy to enhance therapeutic responses in pediatric NHL.

H-Ras regulation of TRAIL death receptor mediated apoptosis

TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis through the death receptors (DRs) 4 and/or 5 expressed on the cell surface. Multiple clinical trials are underway to evaluate the antitumor activity of recombinant human TRAIL and agonistic antibodies to DR4 or DR5. However, their therapeutic potential is limited by the high frequency of cancer resistance. Here we provide evidence demonstrating the role of H-Ras in TRAIL receptor mediated apoptosis. By analyzing the genome wide mRNA expression data of the NCI60 cancer cell lines, we found that H-Ras expression was consistently upregulated in TRAIL-resistant cell lines. By contrast, no correlation was found between TRAIL sensitivity and K-Ras expression levels or their mutational profiles. Notably, H-Ras upregulation associated with a surface deficiency of TRAIL death receptors. Selective inhibition of H-Ras activity in TRAIL-resistant cells restored the surface expression of both DR4 and DR5 without changing their total protein levels. The resulting cells became highly susceptible to both TRAIL and agonistic DR5 antibody, whereas K-Ras inhibition had little or no effect on TRAIL-induced apoptosis, indicating H-Ras plays a distinct role in the regulation of TRAIL death receptors. Further studies are warranted to determine the therapeutic potential of H-Ras-specific inhibitors in combination with TRAIL receptor agonists.

Identification of TRAIL-inducing compounds highlights small molecule ONC201/TIC10 as a unique anti-cancer agent that activates the TRAIL pathway

BACKGROUND

We previously reported the identification of ONC201/TIC10, a novel small molecule inducer of the human TRAIL gene that improves efficacy-limiting properties of recombinant TRAIL and is in clinical trials in advanced cancers based on its promising safety and antitumor efficacy in several preclinical models.

METHODS

We performed a high throughput luciferase reporter screen using the NCI Diversity Set II to identify TRAIL-inducing compounds.

RESULTS

Small molecule-mediated induction of TRAIL reporter activity was relatively modest and the majority of the hit compounds induced low levels of TRAIL upregulation. Among the candidate TRAIL-inducing compounds, TIC9 and ONC201/TIC10 induced sustained TRAIL upregulation and apoptosis in tumor cells in vitro and in vivo. However, ONC201/TIC10 potentiated tumor cell death while sparing normal cells, unlike TIC9, and lacked genotoxicity in normal fibroblasts. Investigating the effects of TRAIL-inducing compounds on cell signaling pathways revealed that TIC9 and ONC201/TIC10, which are the most potent inducers of cell death, exclusively activate Foxo3a through inactivation of Akt/ERK to upregulate TRAIL and its pro-apoptotic death receptor DR5.

CONCLUSION

These studies reveal the selective activity of ONC201/TIC10 that led to its selection as a lead compound for this novel class of antitumor agents and suggest that ONC201/TIC10 is a unique inducer of the TRAIL pathway through its concomitant regulation of the TRAIL ligand and its death receptor DR5.