Caspase 8 is deleted or silenced preferentially in childhood neuroblastomas with amplification of MYCN

Targeting anti-apoptotic mechanisms in tumour cells: Strategies for enhancing Cancer therapy

Anti-cancer drug's cytotoxicity is determined by their ability to induce predetermined cell demise, commonly called apoptosis. The cancer-causing cells are able to evade cell death, which has been affiliated with both malignancy as well as resistance to cancer treatments. In order to avoid cell death, cancerous tumour cells often produce an abundance of anti-apoptotic proteins, becoming "dependent" on them. Consequently, protein inhibitors of cell death may prove to be beneficial as pharmacological targets for the future creation of cancer therapies. This article examines the molecular routes of apoptosis, its clinical manifestations, anti-cancer therapy options that target the intrinsic mechanism of apoptosis, proteins that prevent cell death, and members of the B-lymphoma-2 subset. In addition, novel approaches to cell death are highlighted, including how curcumin mitigates chemotherapy-induced apoptosis in healthy tissues and the various ways melatonin modifies apoptosis to improve cancer treatment efficacy, particularly through the TNF superfamily. Cancer treatment-induced increases in anti-apoptotic proteins lead to drug resistance; yet, ligands that trigger cell death by inhibiting these proteins are expected to improve chemotherapy's efficacy. The potential of frequency-modulated dietary phytochemicals as a cancer therapeutic pathway, including autophagy and apoptosis, is also explored. This approach may be more efficient than inhibition alone in overcoming drug resistance. Consequently, this method has the potential to allow for lower medication concentrations, reducing cytotoxicity and unwanted side effects.

Emerging Trends in Neuroblastoma Diagnosis, Therapeutics, and Research

This review explores the current understanding and recent advancements in neuroblastoma, one of the most common extracranial solid pediatric cancers, accounting for ~ 15% of childhood cancer-related mortality. The hallmarks of NBL, including angiogenesis, metastasis, apoptosis resistance, cell cycle dysregulation, drug resistance, and responses to hypoxia and ROS, underscore its complex biology. The tumor microenvironment's significance in disease progression is acknowledged in this study, along with the pivotal role of cancer stem cells in sustaining tumor growth and heterogeneity. A number of molecular signatures are being studied in order to better understand the disease, with many of them serving as targets for the development of new therapeutics. This includes inhibitor therapies for NBL patients, which notably concentrate on ALK signaling, MDM2, PI3K/Akt/mTOR, Wnt, and RAS-MAPK pathways, along with regulators of epigenetic mechanisms. Additionally, this study offers an extensive understanding of the molecular therapies used, such as monoclonal antibodies and CAR-T therapy, focused on both preclinical and clinical studies. Radiation therapy's evolving role and the promise of stem cell transplantation-mediated interventions underscore the dynamic landscape of NBL treatment. This study has also emphasized the recent progress in the field of diagnosis, encompassing the adoption of artificial intelligence and liquid biopsy as a non-intrusive approach for early detection and ongoing monitoring of NBL. Furthermore, the integration of innovative treatment approaches such as CRISPR-Cas9, and cancer stem cell therapy has also been emphasized in this review.

An activation-based high throughput screen identifies caspase-10 inhibitors

Caspases are a family of highly homologous cysteine proteases that play critical roles in inflammation and apoptosis. Small molecule inhibitors are useful tools for studying caspase biology, complementary to genetic approaches. However, achieving inhibitor selectivity for individual members of this highly homologous enzyme family remains a major challenge in developing such tool compounds. Prior studies have revealed that one strategy to tackle this selectivity gap is to target the precursor or zymogen forms of individual caspases, which share reduced structural homology when compared to active proteases. To establish a screening assay that favors the discovery of zymogen-directed caspase-10 selective inhibitors, we engineered a low-background and high-activity tobacco etch virus (TEV)-activated caspase-10 protein. We then subjected this turn-on protease to a high-throughput screen of approximately 100 000 compounds, with an average Z' value of 0.58 across all plates analyzed. Counter screening, including against TEV protease, delineated bona fide procaspase-10 inhibitors. Confirmatory studies identified a class of thiadiazine-containing compounds that undergo isomerization and oxidation to generate cysteine-reactive compounds with caspase-10 inhibitory activity. In parallel, mode-of-action studies revealed that pifithrin-μ (PFTμ), a reported TP53 inhibitor, also functions as a promiscuous caspase inhibitor. Both inhibitor classes showed preferential zymogen inhibition. Given the generalized utility of activation assays, we expect our screening platform to have widespread applications in identifying state-specific protease inhibitors.

Low Expression of CASP8 Could be a Prognostic Biomarker in Neuroblastoma Patients

The aim of study was to investigate whether CASP8 (CASPASE8) could be a biomarker for prognosis in neuroblastoma. The prognostic value of CASP8 was determined by analyzing CASP8 methylation status and gene expressions in the tumor tissues of 37 neuroblastoma patients. Bisulfite and quantitative multiplex-methylation-specific polymerase chain reaction (PCR) were used to identify the methylation status. CASP8 messenger ribonucleic acid (RNA) expression levels were determined using reverse transcriptase-quantitative PCR. CASP8 expression levels associated with prognostic value were also analyzed using the TARGET NBL (141 cases) database through PDX for Childhood Cancer Therapeutics (PCAT) and SEQC (498 cases) via the R2 platform. CASP8 methylation status was associated with risk groups, MYCN amplification, and 17q gain status. CASP8 expression was found to be statistically different between high- and low-risk neuroblastoma groups. Low expression of CASP8 was associated with MYCN amplification status. Low expression of CASP8 has shown statistically significant prognostic value through TARGET NBL and SEQC-498 data sets. CASP8 messenger RNA expressions and methylation status were associated with the MYCN amplified high-risk group in neuroblastoma. CASP8 messenger RNA expressions may be considered as a clinical prognostic marker in neuroblastoma.

Neuroprotective effects of flavonoids: endoplasmic reticulum as the target

The incidence of neurological disorders, particularly age-related neurodegenerative pathologies, exhibits an alarming upward trend, while current pharmacological interventions seldom achieve curative outcomes. Despite their diverse clinical presentations, neurological diseases often share a common pathological thread: the aberrant accumulation of misfolded proteins within the endoplasmic reticulum (ER). This phenomenon, known as ER stress, arises when the cell's intrinsic quality control mechanisms fail to cope with the protein-folding burden. Consequently, misfolded proteins accumulate in the ER lumen, triggering a cascade of cellular stress responses. Recognizing this challenge, researchers have intensified their efforts over the past two decades to explore natural compounds that could potentially slow or even reverse these devastating pathologies. Flavonoids constitute a vast and heterogeneous class of plant polyphenols, with over 10,000 identified from diverse natural sources such as wines, vegetables, medicinal plants, and organic products. Flavonoids are generally divided into six different subclasses: anthocyanidins, flavanones, flavones, flavonols, isoflavones, and flavonols. The diverse family of flavonoids, featuring a common phenolic ring backbone adorned with varying hydroxyl groups and additional modifications, exerts its antioxidant activity by inhibiting the formation of ROS, as evidenced by research. Also, studies suggest that polyphenols such as flavonoids can regulate ER stress through apoptosis and autophagy. By understanding these mechanisms, we can unlock the potential of flavonoids as novel therapeutic agents for neurodegenerative disorders. Therefore, this review critically examines the literature exploring the modulatory effects of flavonoids on various steps of the ER stress in neurological disorders.

The KAT module of the SAGA complex maintains the oncogenic gene expression program in MYCN-amplified neuroblastoma

Pediatric cancers are frequently driven by genomic alterations that result in aberrant transcription factor activity. Here, we used functional genomic screens to identify multiple genes within the transcriptional coactivator Spt-Ada-Gcn5-acetyltransferase (SAGA) complex as selective dependencies for MYCN-amplified neuroblastoma, a disease of dysregulated development driven by an aberrant oncogenic transcriptional program. We characterized the DNA recruitment sites of the SAGA complex in neuroblastoma and the consequences of loss of SAGA complex lysine acetyltransferase (KAT) activity on histone acetylation and gene expression. We demonstrate that loss of SAGA complex KAT activity is associated with reduced MYCN binding on chromatin, suppression of MYC/MYCN gene expression programs, and impaired cell cycle progression. Further, we showed that the SAGA complex is pharmacologically targetable in vitro and in vivo with a KAT2A/KAT2B proteolysis targeting chimeric. Our findings expand our understanding of the histone-modifying complexes that maintain the oncogenic transcriptional state in this disease and suggest therapeutic potential for inhibitors of SAGA KAT activity in MYCN-amplified neuroblastoma.

Caspase 8 deletion causes infection/inflammation-induced bone marrow failure and MDS-like disease in mice

Myelodysplastic syndromes (MDS) are a heterogeneous group of pre-leukemic hematopoietic disorders characterized by cytopenia in peripheral blood due to ineffective hematopoiesis and normo- or hypercellularity and morphologic dysplasia in bone marrow (BM). An inflammatory BM microenvironment and programmed cell death of hematopoietic stem/progenitor cells (HSPCs) are thought to be the major causes of ineffective hematopoiesis in MDS. Pyroptosis, apoptosis and necroptosis (collectively, PANoptosis) are observed in BM tissues of MDS patients, suggesting an important role of PANoptosis in MDS pathogenesis. Caspase 8 (Casp8) is a master regulator of PANoptosis, which is downregulated in HSPCs from most MDS patients and abnormally spliced in HSPCs from MDS patients with SRSF2 mutation. To study the role of PANoptosis in hematopoiesis, we generated inducible Casp8 knockout mice (Casp8-/-). Mx1-Cre-Casp8-/- mice died of BM failure within 10 days of polyI:C injections due to depletion of HSPCs. Rosa-ERT2Cre-Casp8-/- mice are healthy without significant changes in BM hematopoiesis within the first 1.5 months after Casp8 deletion. Such mice developed BM failure upon infection or low dose polyI:C/LPS injections due to the hypersensitivity of Casp8-/- HSPCs to infection or inflammation-induced necroptosis which can be prevented by Ripk3 deletion. However, impaired self-renewal capacity of Casp8-/- HSPCs cannot be rescued by Ripk3 deletion due to activation of Ripk1-Tbk1 signaling. Most importantly, mice transplanted with Casp8-/- BM cells developed MDS-like disease within 4 months of transplantation as demonstrated by anemia, thrombocytopenia and myelodysplasia. Our study suggests an essential role for a balance in Casp8, Ripk3-Mlkl and Ripk1-Tbk1 activities in the regulation of survival and self-renewal of HSPCs, the disruption of which induces inflammation and BM failure, resulting in MDS-like disease.

Death Induced by Survival gene Elimination (DISE) correlates with neurotoxicity in Alzheimer's disease and aging

Alzheimer's disease (AD) is characterized by progressive neurodegeneration, but the specific events that cause cell death remain poorly understood. Death Induced by Survival gene Elimination (DISE) is a cell death mechanism mediated by short (s) RNAs acting through the RNA-induced silencing complex (RISC). DISE is thus a form of RNA interference, in which G-rich 6mer seed sequences in the sRNAs (position 2-7) target hundreds of C-rich 6mer seed matches in genes essential for cell survival, resulting in the activation of cell death pathways. Here, using Argonaute precipitation and RNAseq (Ago-RP-Seq), we analyze RISC-bound sRNAs to quantify 6mer seed toxicity in several model systems. In mouse AD models and aging brain, in induced pluripotent stem cell-derived neurons from AD patients, and in cells exposed to Aβ42 oligomers, RISC-bound sRNAs show a shift to more toxic 6mer seeds compared to controls. In contrast, in brains of "SuperAgers", humans over age 80 who have superior memory performance, RISC-bound sRNAs are shifted to more nontoxic 6mer seeds. Cells depleted of nontoxic sRNAs are sensitized to Aβ42-induced cell death, and reintroducing nontoxic RNAs is protective. Altogether, the correlation between DISE and Aβ42 toxicity suggests that increasing the levels of nontoxic miRNAs in the brain or blocking the activity of toxic RISC-bound sRNAs could ameliorate neurodegeneration.

Splicing DNA Damage Adaptations for the Management of Cancer Cells

Maintaining a tumour cell's resistance to apoptosis (organized cell death) is essential for cancer to metastasize. Signal molecules play a critical function in the tightly regulated apoptotic process. Apoptosis may be triggered by a wide variety of cellular stresses, including DNA damage, but its ultimate goal is always the same: the removal of damaged cells that might otherwise develop into tumours. Many chemotherapy drugs rely on cancer cells being able to undergo apoptosis as a means of killing them. The mechanisms by which DNA-damaging agents trigger apoptosis, the interplay between pro- and apoptosis-inducing signals, and the potential for alteration of these pathways in cancer are the primary topics of this review.

Rubiarbonol B induces RIPK1-dependent necroptosis via NOX1-derived ROS production

The activation of receptor-interacting protein kinase 1 (RIPK1) by death-inducing signaling complex (DISC) formation is essential for triggering the necroptotic mode of cell death under apoptosis-deficient conditions. Thus, targeting the induction of necroptosis by modulating RIPK1 activity could be an effective strategy to bypass apoptosis resistance in certain types of cancer. In this study, we screened a series of arborinane triterpenoids purified from Rubia philippinesis and identified rubiarbonol B (Ru-B) as a potent caspase-8 activator that induces DISC-mediated apoptosis in multiple types of cancer cells. However, in RIPK3-expressing human colorectal cancer (CRC) cells, the pharmacological or genetic inhibition of caspase-8 shifted the mode of cell death by Ru-B from apoptosis to necroptosis though upregulation of RIPK1 phosphorylation. Conversely, Ru-B-induced cell death was almost completely abrogated by RIPK1 deficiency. The enhanced RIPK1 phosphorylation and necroptosis triggered by Ru-B treatment occurred independently of tumor necrosis factor receptor signaling and was mediated by the production of reactive oxygen species via NADPH oxidase 1 in CRC cells. Thus, we propose Ru-B as a novel anticancer agent that activates RIPK1-dependent cell death via ROS production, and suggest its potential as a novel necroptosis-targeting compound in apoptosis-resistant CRC.

Caspase-8 and Tyrosine Kinases: A Dangerous Liaison in Cancer

Caspase-8 is a cysteine-aspartic acid protease that has been identified as an initiator caspase that plays an essential role in the extrinsic apoptotic pathway. Evasion of apoptosis is a hallmark of cancer and Caspase-8 expression is silenced in some tumors, consistent with its central role in apoptosis. However, in the past years, several studies reported an increased expression of Caspase-8 levels in many tumors and consistently identified novel "non-canonical" non-apoptotic functions of Caspase-8 that overall promote cancer progression and sustain therapy resistance. These reports point to the ability of cancer cells to rewire Caspase-8 function in cancer and raise the question of which are the signaling pathways aberrantly activated in cancer that may contribute to the hijack of Caspase-8 activity. In this regard, tyrosine kinases are among the first oncogenes ever identified and genomic, transcriptomic and proteomic studies indeed show that they represent a class of signaling molecules constitutively activated in most of the tumors. Here, we aim to review and discuss the role of Caspase-8 in cancer and its interplay with Src and other tyrosine kinases.

Metastasis in neuroblastoma: the MYCN question

Oncogenic drivers like MYCN in neuroblastoma subsets continues to present a significant challenge owing to its strong correlation with high-risk metastatic disease and poor prognosis. However, only a limited number of MYCN-regulatory proteins associated with tumor initiation and progression have been elucidated. In this minireview, I summarize the recent progress in understanding the functional role of MYCN and its regulatory partners in neuroblastoma metastasis.

The caspase-8 and procaspase-3 expression in gastric cancer and non-cancer mucosa in relation to clinico-morphological factors and some apoptosis-associated proteins

PURPOSE

The aim of the study was to assess the expression of caspase-8 and procaspase-3 proteins in gastric cancer (GC) cells and non-cancerous mucosa in relation to clinical and morphological characteristics of the tumor, postoperative survival as well as other apoptosis-related proteins.

MATERIALS AND METHODS

The study included 91 ​GC patients. Expression of the proteins was assessed using immunohistochemical method.

RESULTS

Positive expression of procaspase-3 was found in all GC cells. A significant difference was found between high expression of this protein in cancer cells (70.3%) and non-cancerous mucosa (1.25%) (p ​≤ ​0.05). Caspase-8 expression was observed in 50.7% of GC cells and 46.7% of mucosa. Caspase-8 was more common in Lauren type II compared to Lauren type I cancer (p ​= ​0.009), while a statistically significant difference was reported between positive procaspase-3 expression and differentiation of GC (p ​= ​0.043) and Lauren's classification (p ​= ​0.028). We observed a significant positive correlation between the expression of caspase-8 and bcl-xl (p ​= ​0.030) as well as between the procaspase-3 and BID (p ​= ​0.026). Positive caspase-8 expression was associated with longer survival of GC patients (p ​≤ ​0.01).

CONCLUSIONS

Our findings indicate the potential role of the analyzed proteins in GC pathogenesis. Positive expression of caspase-8 is associated with longer survival and better patient prognosis.

The interaction of CFLAR with p130Cas promotes cell migration

CASP8 and FADD Like Apoptosis Regulator (CFLAR) is a key anti-apoptotic regulator for resistance to apoptosis mediated by Fas and TRAIL. In addition to its anti-apoptotic function, CFLAR is also an important mediator of tumor growth. High level of CFLAR expression correlates with a more aggressive tumor. However, the mechanism of CFLAR signaling in malignant progression is not clear. Here we report a novel CFLAR-associated protein p130Cas, which is a general regulator of cell growth and cell migration. CFLAR-p130Cas association is mediated by the DED domain of CFLAR and the SD domain of p130Cas. Immunofluorescence observation showed that CFLAR had the colocalization with p130Cas at the focal adhesion of cell membrane. CFLAR overexpression promoted p130Cas phosphorylation and the formation of focal adhesion complex. Moreover, the enhancement of cell migration induced by CFLAR overexpression was obviously inhibited by p130Cas siRNA. In silico analysis on human database suggests high expressions of CFLAR or/and p130Cas are associated with poor prognosis of patients with lung cancer. Together, our results suggest a new mechanism for CFLAR involved in tumor development via association with p130Cas.

Liquidhope: methylome and genomic profiling from very limited quantities of plasma-derived DNA

Analysis of the methylome of tumor cell-free deoxyribonucleic acid (DNA; cfDNA) has emerged as a powerful non-invasive technique for cancer subtyping and prognosis. However, its application is frequently hampered by the quality and total cfDNA yield. Here, we demonstrate the feasibility of very low-input cfDNA for whole-methylome and copy-number profiling studies using enzymatic conversion of unmethylated cysteines [enzymatic methyl-seq (EM-seq)] to better preserve DNA integrity. We created a model for predicting genomic subtyping and prognosis with high accuracy. We validated our tool by comparing whole-genome CpG sequencing with in situ cohorts generated with bisulfite conversion and array hybridization, demonstrating that, despite the different techniques and sample origins, information on cfDNA methylation is comparable with in situ cohorts. Our findings support use of liquid biopsy followed by EM-seq to assess methylome of cancer patients, enabling validation in external cohorts. This advance is particularly relevant for rare cancers like neuroblastomas where liquid-biopsy volume is restricted by ethical regulations in pediatric patients.

The length of uninterrupted CAG repeats in stem regions of repeat disease associated hairpins determines the amount of short CAG oligonucleotides that are toxic to cells through RNA interference

Extended CAG trinucleotide repeats (TNR) in the genes huntingtin (HTT) and androgen receptor (AR) are the cause of two progressive neurodegenerative disorders: Huntington's disease (HD) and Spinal and Bulbar Muscular Atrophy (SBMA), respectively. Anyone who inherits the mutant gene in the complete penetrance range (>39 repeats for HD and 44 for SBMA) will develop the disease. An inverse correlation exists between the length of the CAG repeat and the severity and age of onset of the diseases. Growing evidence suggests that it is the length of uninterrupted CAG repeats in the mRNA rather than the length of poly glutamine (polyQ) in mutant (m)HTT protein that determines disease progression. One variant of mHTT (loss of inhibition; LOI) causes a 25 year earlier onset of HD when compared to a reference sequence, despite both coding for a protein that contains an identical number of glutamines. Short 21-22 nt CAG repeat (sCAGs)-containing RNAs can cause disease through RNA interference (RNAi). RNA hairpins (HPs) forming at the CAG TNRs are stabilized by adjacent CCG (in HD) or CUG repeats (in SBMA) making them better substrates for Dicer, the enzyme that processes CAG HPs into sCAGs. We now show that cells deficient in Dicer or unable to mediate RNAi are resistant to the toxicity of the HTT and AR derived HPs. Expression of a small HP that mimics the HD LOI variant is more stable and more toxic than a reference HP. We report that the LOI HP is processed by Dicer, loaded into the RISC more efficiently, and gives rise to a higher quantity of RISC-bound 22 nt sCAGs. Our data support the notion that RNAi contributes to the cell death seen in HD and SBMA and provide an explanation for the dramatically reduced onset of disease in HD patients that carry the LOI variant.

Comparative epigenomics by machine learning approach for neuroblastoma

BACKGROUND

Neuroblastoma (NB) is the second most common pediatric solid tumor. Because the number of genetic mutations found in tumors are small, even in some patients with unfavorable NB, epigenetic variation is expected to play an important role in NB progression. DNA methylation is a major epigenetic mechanism, and its relationship with NB prognosis has been a concern. One limitation with the analysis of variation in DNA methylation is the lack of a suitable analytical model. Therefore, in this study, we performed a random forest (RF) analysis of the DNA methylome data of NB from multiple databases.

RESULTS

RF is a popular machine learning model owing to its simplicity, intuitiveness, and computational cost. RF analysis identified novel intermediate-risk patient groups with characteristic DNA methylation patterns within the low-risk group. Feature selection analysis based on probe annotation revealed that enhancer-annotated regions had strong predictive power, particularly for MYCN-amplified NBs. We developed a gene-based analytical model to identify candidate genes related to disease progression, such as PRDM8 and FAM13A-AS1. RF analysis revealed sufficient predictive power compared to other machine learning models.

CONCLUSIONS

RF is a useful tool for DNA methylome analysis in cancer epigenetic studies, and has potential to identify a novel cancer-related genes.

High expression of caspase‐8 as a predictive factor of poor prognosis in patients with esophageal cancer

BACKGROUND

Esophageal carcinoma (ESCA) is considered to be one of the most common gastrointestinal cancers. Caspase-8 (CASP8) is a key protein of cross-talk signaling in a variety of cancers. However, the role of CASP8 expression in the prognosis of patients with ESCA has remained unexplored. Hence, it is needed to explore the clinical significance of CASP8 expression in ESCA.

METHODS

The expression and prognosis of CASP8 were investigated in ESCA using the UALCAN, GEDS, TIMER, and OncoLnc databases. The CASP8 genetic variations in ESCA were assessed using the cBioPortal database. The correlation between CASP8 expression and tumor immune invasion and immune cell surface indicators was examined using the TIMER and TISIDTISIDB datasets. Meanwhile, the abundance of the immunological cells in the tumor and healthy tissues was assessed by the CIBERSORT method. Next, information on the co-expressed genes of the differentially expressed genes (DEGs) in ESCA-tumor and ESCA-healthy tissues was obtained using the cBioPortal, UALCAN, and Coexpedia databases. Subsequently, the PPI network was constructed and the GO and KEGG pathways were analyzed using the SIRING database. Finally, CASP8 mRNA and protein expression in the ESCA tissues and matched adjacent healthy tissues were analyzed using qRT-PCR, immune-blotting, and immunohistochemistry. Additionally, the relationship between clinicopathological features and CASP8 expression was assessed.

RESULTS

ESCA tissues had higher levels of CASP8 mRNA and protein expression compared to healthy tissues. patients with an elevated level of CASP8 expression had poor overall survival (OS). CASP8 expression was significantly correlated with the degree of differentiation (P = 0.004) and lymph node metastasis (P = 0.044). There were diverse patterns of association between immunological cell surface biomarkers and CASP8 expression.

CONCLUSION

ESCA showed significant levels of CASP8 expression which may serve as a prognostic biomarker correlated to immune infiltrates in ESCA.

The dual role of the CD95 and CD95L signaling pathway in glioblastoma

Binding of CD95, a cell surface death receptor, to its homologous ligand CD95L, transduces a cascade of downstream signals leading to apoptosis crucial for immune homeostasis and immune surveillance. Although CD95 and CD95L binding classically induces programmed cell death, most tumor cells show resistance to CD95L-induced apoptosis. In some cancers, such as glioblastoma, CD95-CD95L binding can exhibit paradoxical functions that promote tumor growth by inducing inflammation, regulating immune cell homeostasis, and/or promoting cell survival, proliferation, migration, and maintenance of the stemness of cancer cells. In this review, potential mechanisms such as the expression of apoptotic inhibitor proteins, decreased activity of downstream elements, production of nonapoptotic soluble CD95L, and non-apoptotic signals that replace apoptotic signals in cancer cells are summarized. CD95L is also expressed by other types of cells, such as endothelial cells, polymorphonuclear myeloid-derived suppressor cells, cancer-associated fibroblasts, and tumor-associated microglia, and macrophages, which are educated by the tumor microenvironment and can induce apoptosis of tumor-infiltrating lymphocytes, which recognize and kill cancer cells. The dual role of the CD95-CD95L system makes targeted therapy strategies against CD95 or CD95L in glioblastoma difficult and controversial. In this review, we also discuss the current status and perspective of clinical trials on glioblastoma based on the CD95-CD95L signaling pathway.

Lethal and Non-Lethal Functions of Caspases in the DNA Damage Response

Members of the caspase family are well known for their roles in the initiation and execution of cell death. Due to their function in the removal of damaged cells that could otherwise become malignant, caspases are important players in the DNA damage response (DDR), a network of pathways that prevent genomic instability. However, emerging evidence of caspases positively or negatively impacting the accumulation of DNA damage in the absence of cell death demonstrates that caspases play a role in the DDR that is independent of their role in apoptosis. This review highlights the apoptotic and non-apoptotic roles of caspases in the DDR and how they can impact genomic stability and cancer treatment.

The PRC2 molecule EED is a target of epigenetic therapy for neuroblastoma

Epigenetic modifications by polycomb repressive complex (PRC) molecules appear to play a role in the tumorigenesis and aggressiveness of neuroblastoma (NB). Embryonic ectoderm development (EED) is a member of the PRC2 complex that binds to the H3K27me3 mark deposited by EZH2 via propagation on adjacent nucleosomes. We herein investigated the molecular roles of EED in MYCN-amplified NB cells using EED-knockdown (KD) shRNAs, EED-knockout sgRNAs, and the EED small molecule inhibitor EED226. The suppression of EED markedly inhibited NB cell proliferation and flat and soft agar colony formation. A transcriptome analysis using microarrays of EED-KD NB cells indicated the de-repression of cell cycle-regulated and differentiation-related genes. The results of a GSEA analysis suggested that inhibitory cell cycle-regulated gene sets were markedly up-regulated. Furthermore, an epigenetic treatment with the EED inhibitor EED226 and the HDAC inhibitors valproic acid/SAHA effectively suppressed NB cell proliferation and colony formation. This combined epigenetic treatment up-regulated cell cycle-regulated and differentiation-related genes. The ChIP sequencing analysis of histone codes and PRC molecules suggested an epigenetic background for the de-repression of down-regulated genes in MYCN-amplified/PRC2 up-regulated NB.

The MYC oncogene - the grand orchestrator of cancer growth and immune evasion

The MYC proto-oncogenes encode a family of transcription factors that are among the most commonly activated oncoproteins in human neoplasias. Indeed, MYC aberrations or upregulation of MYC-related pathways by alternate mechanisms occur in the vast majority of cancers. MYC proteins are master regulators of cellular programmes. Thus, cancers with MYC activation elicit many of the hallmarks of cancer required for autonomous neoplastic growth. In preclinical models, MYC inactivation can result in sustained tumour regression, a phenomenon that has been attributed to oncogene addiction. Many therapeutic agents that directly target MYC are under development; however, to date, their clinical efficacy remains to be demonstrated. In the past few years, studies have demonstrated that MYC signalling can enable tumour cells to dysregulate their microenvironment and evade the host immune response. Herein, we discuss how MYC pathways not only dictate cancer cell pathophysiology but also suppress the host immune response against that cancer. We also propose that therapies targeting the MYC pathway will be key to reversing cancerous growth and restoring antitumour immune responses in patients with MYC-driven cancers.

Predicting amplification of MYCN using CpG methylation biomarkers in neuroblastoma

Background: Neuroblastoma is the most common extracranial solid tumor in childhood. Amplification of MYCN in neuroblastoma is a predictor of poor prognosis. Materials and methods: DNA methylation data from the TARGET data matrix were stratified into MYCN amplified and non-amplified groups. Differential methylation analysis, clustering, recursive feature elimination (RFE), machine learning (ML), Cox regression analysis and Kaplan-Meier estimates were performed. Results and Conclusion: 663 CpGs were differentially methylated between the two groups. A total of 25 CpGs were selected by RFE for clustering and ML, and a 100% clustering accuracy was obtained. ML validation on three external datasets produced high accuracy scores of 100%, 97% and 93%. Eight survival-associated CpGs were also identified. Therapeutic interventions may need to be targeted to patient subgroups.

Identification of the Novel Methylated Genes' Signature to Predict Prognosis in INRG High-Risk Neuroblastomas

BACKGROUND

Neuroblastomas are the most frequent extracranial pediatric solid tumors. The prognosis of children with high-risk neuroblastomas has remained poor in the past decade. A powerful signature is required to identify factors associated with prognosis and improved treatment selection. Here, we identified a strong methylation signature that favored the earlier diagnosis of neuroblastoma in patients.

METHODS

Gene methylation (GM) data of neuroblastoma patients from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) were analyzed using a multivariate Cox regression analysis (MCRA) and univariate Cox proportional hazards regression analysis (UCPHRA).

RESULTS

The methylated genes' signature consisting of eight genes (NBEA, DDX28, TMED8, LOC151174, EFNB2, GHRHR, MIMT1, and SLC29A3) was selected. The signature divided patients into low- and high-risk categories, with statistically significant survival rates (median survival time: 25.08 vs. >128.80 months, log-rank test, P < 0.001) in the training group, and the validation of the signature's risk stratification ability was carried out in the test group (log-rank test, P < 0.01, median survival time: 30.48 vs. >120.36 months). The methylated genes' signature was found to be an independent predictive factor for neuroblastoma by MCRA. Functional enrichment analysis suggested that these methylated genes were related to butanoate metabolism, beta-alanine metabolism, and glutamate metabolism, all playing different significant roles in the process of energy metabolism in neuroblastomas.

CONCLUSIONS

The set of eight methylated genes could be used as a new predictive and prognostic signature for patients with INRG high-risk neuroblastomas, thus assisting in treatment, drug development, and predicting survival.

Mechanisms involved in selecting and maintaining neuroblastoma cancer stem cell populations, and perspectives for therapeutic targeting

Pediatric neuroblastomas (NBs) are heterogeneous, aggressive, therapy-resistant embryonal tumours that originate from cells of neural crest (NC) origin and in particular neuroblasts committed to the sympathoadrenal progenitor cell lineage. Therapeutic resistance, post-therapeutic relapse and subsequent metastatic NB progression are driven primarily by cancer stem cell (CSC)-like subpopulations, which through their self-renewing capacity, intermittent and slow cell cycles, drug-resistant and reversibly adaptive plastic phenotypes, represent the most important obstacle to improving therapeutic outcomes in unfavourable NBs. In this review, dedicated to NB CSCs and the prospects for their therapeutic eradication, we initiate with brief descriptions of the unique transient vertebrate embryonic NC structure and salient molecular protagonists involved NC induction, specification, epithelial to mesenchymal transition and migratory behaviour, in order to familiarise the reader with the embryonic cellular and molecular origins and background to NB. We follow this by introducing NB and the potential NC-derived stem/progenitor cell origins of NBs, before providing a comprehensive review of the salient molecules, signalling pathways, mechanisms, tumour microenvironmental and therapeutic conditions involved in promoting, selecting and maintaining NB CSC subpopulations, and that underpin their therapy-resistant, self-renewing metastatic behaviour. Finally, we review potential therapeutic strategies and future prospects for targeting and eradication of these bastions of NB therapeutic resistance, post-therapeutic relapse and metastatic progression.

The Most Competent Plant-Derived Natural Products for Targeting Apoptosis in Cancer Therapy

Cancer is a challenging problem for the global health community, and its increasing burden necessitates seeking novel and alternative therapies. Most cancers share six basic characteristics known as "cancer hallmarks", including uncontrolled proliferation, refractoriness to proliferation blockers, escaping apoptosis, unlimited proliferation, enhanced angiogenesis, and metastatic spread. Apoptosis, as one of the best-known programmed cell death processes, is generally promoted through two signaling pathways, including the intrinsic and extrinsic cascades. These pathways comprise several components that their alterations can render an apoptosis-resistance phenotype to the cell. Therefore, targeting more than one molecule in apoptotic pathways can be a novel and efficient approach for both identifying new anticancer therapeutics and preventing resistance to therapy. The main purpose of this review is to summarize data showing that various plant extracts and plant-derived molecules can activate both intrinsic and extrinsic apoptosis pathways in human cancer cells, making them attractive candidates in cancer treatment.

Mitochondria and nucleus cross-talk: Signaling in metabolism, apoptosis, and differentiation, and function in cancer

The cross-talk between the mitochondrion and the nucleus regulates cellular functions, including differentiation and adaptation to stress. Mitochondria supply metabolites for epigenetic modifications and other nuclear-associated activities and certain mitochondrial proteins were found in the nucleus. The voltage-dependent anion channel 1 (VDAC1), localized at the outer mitochondrial membrane (OMM) is a central protein in controlling energy production, cell growth, Ca2+ homeostasis, and apoptosis. To alter the cross-talk between the mitochondria and the nucleus, we used specific siRNA to silence the expression of VDAC1 in glioblastoma (GBM) U87-MG and U118-MG cell-derived tumors, and then monitored the nuclear localization of mitochondrial proteins and the methylation and acetylation of histones. Depletion of VDAC1 from tumor cells reduced metabolism, leading to inhibition of tumor growth, and several tumor-associated processes and signaling pathways linked to cancer development. In addition, we demonstrate that certain mitochondrial pro-apoptotic proteins such as caspases 3, 8, and 9, and p53 were unexpectedly overexpressed in tumors, suggesting that they possess additional non-apoptotic functions. VDAC1 depletion and metabolic reprograming altered their expression levels and subcellular localization, specifically their translocation to the nucleus. In addition, VDAC1 depletion also leads to epigenetic modifications of histone acetylation and methylation, suggesting that the interchange between metabolism and cancer signaling pathways involves mitochondria-nucleus cross-talk. The mechanisms regulating mitochondrial protein trafficking into and out of the nucleus and the role these proteins play in the nucleus remain to be elucidated.

Neuroblastoma and the epigenome

Neuroblastoma (NB) is a pediatric cancer of the sympathetic nervous system and one of the most common solid tumors in infancy. Amplification of MYCN, copy number alterations, numerical and segmental chromosomal aberrations, mutations, and rearrangements on a handful of genes, such as ALK, ATRX, TP53, RAS/MAPK pathway genes, and TERT, are attributed as underlying causes that give rise to NB. However, the heterogeneous nature of the disease-along with the relative paucity of recurrent somatic mutations-reinforces the need to understand the interplay of genetic factors and epigenetic alterations in the context of NB. Epigenetic mechanisms tightly control gene expression, embryogenesis, imprinting, chromosomal stability, and tumorigenesis, thereby playing a pivotal role in physio- and pathological settings. The main epigenetic alterations include aberrant DNA methylation, disrupted patterns of posttranslational histone modifications, alterations in chromatin composition and/or architecture, and aberrant expression of non-coding RNAs. DNA methylation and demethylation are mediated by DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) proteins, respectively, while histone modifications are coordinated by histone acetyltransferases and deacetylases (HATs, HDACs), and histone methyltransferases and demethylases (HMTs, HDMs). This article focuses predominately on the crosstalk between the epigenome and NB, and the implications it has on disease diagnosis and treatment.

Causes, effects, and clinical implications of perturbed patterns within the cancer epigenome

Somatic mutations accumulating over a patient's lifetime are well-defined causative factors that fuel carcinogenesis. It is now clear, however, that epigenomic signature is also largely perturbed in many malignancies. These alterations support the transcriptional program crucial for the acquisition and maintenance of cancer hallmarks. Epigenetic instability may arise due to the genetic mutations or transcriptional deregulation of the proteins implicated in epigenetic signaling. Moreover, external stimulation and physiological aging may also participate in this phenomenon. The epigenomic signature is frequently associated with a cell of origin, as well as with tumor stage and differentiation, which all reflect its high heterogeneity across and within various tumors. Here, we will overview the current understanding of the causes and effects of the altered and heterogeneous epigenomic landscape in cancer. We will focus mainly on DNA methylation and post-translational histone modifications as the key regulatory epigenetic signaling marks. In addition, we will describe how this knowledge is translated into the clinic. We will particularly concentrate on the applicability of epigenetic alterations as biomarkers for improved diagnosis, prognosis, and prediction. Finally, we will also review current developments regarding epi-drug usage in clinical and experimental settings.

Association of RASSF1A, DCR2, and CASP8 Methylation with Survival in Neuroblastoma: A Pooled Analysis Using Reconstructed Individual Patient Data

Neuroblastoma (NB) is a heterogeneous tumor affecting children. It shows a wide spectrum of clinical outcomes; therefore, development of risk stratification is critical to provide optimum treatment. Since epigenetic alterations such as DNA methylation have emerged as an important feature of both development and progression in NB, in this study, we aimed to quantify the effect of methylation of three distinct genes (RASSF1A, DCR2, and CASP8) on overall survival in NB patients. We performed a systematic review using PubMed, Embase, and Cochrane libraries. Individual patient data was retrieved from extracted Kaplan–Meier curves. Data from studies was then merged, and analysis was done on the full data set. Seven studies met the inclusion criteria. Methylation of the three genes had worse overall survival than the unmethylated arms. Five-year survival for the methylated arm of RASSF1A, DCR2, and CASP8 was 63.19% (95% CI 56.55-70.60), 57.78% (95% CI 47.63-70.08), and 56.39% (95% CI 49.53-64.19), respectively, while for the unmethylated arm, it was 93.10% (95% CI 87.40–99.1), 84.84% (95% CI 80.04-89.92), and 83.68% (95% CI 80.28-87.22), respectively. In conclusion, our results indicate that in NB patients, RASSF1A, DCR2, and CASP8 methylation is associated with poor prognosis. Large prospective studies will be necessary to confirm definitive correlation between methylation of these genes and survival taking into account all other known risk factors. (PROSPERO registration number CRD42017082264).

Caspase-8 loss radiosensitizes head and neck squamous cell carcinoma to SMAC mimetic-induced necroptosis

Caspase-8 (CASP8) is one of the most frequently mutated genes in head and neck squamous carcinomas (HNSCCs), and CASP8 mutations are associated with poor survival. The distribution of these mutations in HNSCCs suggests that they are likely to be inactivating. Inhibition of CASP8 has been reported to sensitize cancer cells to necroptosis, a regulated cell death mechanism. Here, we show that knockdown of CASP8 renders HNSCCs susceptible to necroptosis by a second mitochondria-derived activator of caspase (SMAC) mimetic, birinapant, in combination with pan-caspase inhibitors Z-VAD-FMK or emricasan and radiation. In a syngeneic mouse model of oral cancer, birinapant, particularly when combined with radiation, delayed tumor growth and enhanced survival under CASP8 loss. Exploration of molecular underpinnings of necroptosis sensitivity confirmed that the level of functional receptor-interacting serine/threonine protein kinase 3 (RIP3) determines susceptibility to this mode of death. Although an in vitro screen revealed that low RIP3 levels rendered many HNSCC cell lines resistant to necroptosis, patient tumors maintained RIP3 expression and should therefore remain sensitive. Collectively, these results suggest that targeting the necroptosis pathway with SMAC mimetics, especially in combination with radiation, may be relevant therapeutically in HNSCC with compromised CASP8 status, provided that RIP3 function is maintained.

Mouse models of high-risk neuroblastoma

Informative and realistic mouse models of high-risk neuroblastoma are central to understanding mechanisms of tumour initiation, progression, and metastasis. They also play vital roles in validating tumour drivers and drug targets, as platforms for assessment of new therapies and in the generation of drug sensitivity data that can inform treatment decisions for individual patients. This review will describe genetically engineered mouse models of specific subsets of high-risk neuroblastoma, the development of patient-derived xenograft models that more broadly represent the diversity and heterogeneity of the disease, and models of primary and metastatic disease. We discuss the research applications, advantages, and limitations of each model type, the importance of model repositories and data standards for supporting reproducible, high-quality research, and potential future directions for neuroblastoma mouse models.

A review of fasting effects on the response of cancer to chemotherapy

BACKGROUND & AIMS

Studies suggest that fasting before or during chemotherapy may induce differential stress resistance, reducing the adverse effects of chemotherapy and enhancing the efficacy of drugs. In this article, we review the effects of fasting, including intermittent, periodic, water-only short-term fasting, and caloric restriction on the responsiveness of tumor cells to cytotoxic drugs, their protective effect on normal cells, and possible mechanisms of action.

METHODS

We could not perform a systematic review due to the wide variation in the study population, design, dependent measures, and outcomes (eg, type of cancer, treatment variation, experimental setting, etc.). However, a systematic approach to search and review literature was used. The electronic databases PubMed (MEDLINE), Scopus, and Embase were searched up to July 2020.

RESULTS

Fasting potentially improves the response of tumor cells to chemotherapy by (1) repairing DNA damage in normal tissues (but not tumor cells); (2) upregulating autophagy flux as a protection against damage to organelles and some cancer cells; (3) altering apoptosis and increasing tumor cells' sensitivity to the apoptotic stimuli, and preventing apoptosis-mediated damage to normal cells; (4) depleting regulatory T cells and improving the stimulation of CD8 cells; and (5) accumulating unfolded proteins and protecting cancer cells from immune surveillance. We also discuss how 'fasting-mimicking diet' as a modified form of fasting enables patients to eat a low calorie, low protein, and low sugar diet while achieving similar metabolic outcomes of fasting.

CONCLUSION

This review suggests the potential benefits of fasting in combination with chemotherapy to reduce tumor progression and increase the effectiveness of chemotherapy. However, with limited human trials, it is not possible to generalize the findings from animal and in vitro studies. More human studies with adequate sample size and follow-ups are required to confirm these findings.

Circulating tumor DNA in neuroblastoma

As a sympathetic nervous system-derived tumor, aggressive neuroblastoma (NB) is currently attracting interest from researchers seeking diagnostic and prognostic markers via less invasive procedures. The analysis of circulating tumor DNA (ctDNA) in peripheral blood can provide genetic information from multiple tumor lesions and is not dependent on a surgical procedure. The identification of genetic alterations, chromosomal variations, and hypermethylation contained within plasma DNA yields clinical value in the diagnosis, risk stratification, monitoring of treatment effects, and survival prediction for patients. With the widespread application of genome sequencing, droplet digital polymerase chain reaction, and other advanced technologies, the detection of ctDNA may guide therapeutic schedules, enhance the quality of life, and improve the prognosis for patients with NB.

Multiple roles of caspase-8 in cell death, inflammation, and innate immunity

Caspase-8 is an apical caspase involved in the programmed form of cell death called apoptosis that is critically important for mammalian development and immunity. Apoptosis was historically described as immunologically silent in contrast to other types of programmed cell death such as necroptosis or pyroptosis. Recent reports suggest considerable crosstalk between these different forms of cell death. It is becoming increasingly clear that caspase-8 has many non-apoptotic roles, participating in multiple processes including regulation of necroptosis (mediated by receptor-interacting serine/threonine kinases, RIPK1-RIPK3), inflammatory cytokine expression, inflammasome activation, and cleavage of IL-1β and gasdermin D, and protection against shock and microbial infection. In this review, we discuss the involvement of caspase-8 in cell death and inflammation and highlight its role in innate immune responses and in the relationship between different forms of cell death. Caspase-8 is one of the central components in this type of crosstalk.

A direct comparison of selective BH3-mimetics reveals BCL-XL, BCL-2 and MCL-1 as promising therapeutic targets in neuroblastoma

Background

Despite advances in the treatment of neuroblastoma, patients with high-risk disease still have dismal survival prognosis. Neuroblastoma cells display elevated expression of the antiapoptotic BCL-2 proteins, suggesting that BH3-mimetics may be a promising treatment option. Here, we investigated the role of BCL-2, BCL-X_L and MCL-1 in neuroblastoma.

Methods

A panel of neuroblastoma cell lines and primary patient-derived cells were exposed to BH3-mimetics targeting BCL-2 (ABT-199), BCL-X_L (A1331852) or MCL-1 (S63845). In addition, protein expression and interaction patterns were analysed using Western blotting and immunoprecipitation.

Results

All tested BH3-mimetics were able to induce apoptosis in neuroblastoma cell lines, indicating that not only BCL-2 but also BCL-X_L and MCL-1 may be promising therapeutic targets. Primary patient-derived cells displayed highest sensitivity to A1331852, highlighting the important role of BCL-X_L in neuroblastoma. Further analysis into the molecular mechanisms of apoptosis revealed that A1331852 and S63845 displaced proapoptotic proteins like BIM and BAK from their antiapoptotic targets, subsequently leading to the activation of BAX and BAK and caspase-dependent apoptosis.

Conclusions

By using selective BH3-mimetics, this study demonstrates that BCL-2, BCL-X_L, and MCL-1 are all relevant therapeutic targets in neuroblastoma. A1331852 and S63845 induce rapid apoptosis that is initiated following a displacement of BAK from BCL-X_L or MCL-1, respectively.

Cancer Cells Employ Nuclear Caspase-8 to Overcome the p53-Dependent G2/M Checkpoint through Cleavage of USP28

Cytosolic caspase-8 is a mediator of death receptor signaling. While caspase-8 expression is lost in some tumors, it is increased in others, indicating a conditional pro-survival function of caspase-8 in cancer. Here, we show that tumor cells employ DNA-damage-induced nuclear caspase-8 to override the p53-dependent G2/M cell-cycle checkpoint. Caspase-8 is upregulated and localized to the nucleus in multiple human cancers, correlating with treatment resistance and poor clinical outcome. Depletion of caspase-8 causes G2/M arrest, stabilization of p53, and induction of p53-dependent intrinsic apoptosis in tumor cells. In the nucleus, caspase-8 cleaves and inactivates the ubiquitin-specific peptidase 28 (USP28), preventing USP28 from de-ubiquitinating and stabilizing wild-type p53. This results in de facto p53 protein loss, switching cell fate from apoptosis toward mitosis. In summary, our work identifies a non-canonical role of caspase-8 exploited by cancer cells to override the p53-dependent G2/M cell-cycle checkpoint.

Caspase-8: The double-edged sword

Caspase-8 is a cysteine - aspartate specific protease that classically triggers the extrinsic apoptotic pathway, in response to the activation of cell surface Death Receptors (DRs) like FAS, TRAIL-R and TNF-R. Besides it's roles in triggering death receptor-mediated apoptosis, Caspase-8 has also been implicated in the onsets of anoikis, autophagy and pyroptosis. Furthermore, Caspase-8 also plays a crucial pro-survival function by inhibiting an alternative form of programmed cell death called necroptosis. Low expression levels of pro-Caspase-8 is therefore associated with the malignant transformation of cancers. However, the long-held notion that pro-Caspase-8 expression/activity is generally lost in most cancers, thereby contributing to apoptotic escape and enhanced resistance to anti-cancer therapeutics, has been found to be true for only a minority of cancers types. In the majority of cases, pro-Caspase-8 expression is maintained and sometimes elevated, while it's apoptotic activity is regulated through different mechanisms. This supports the notion that the non-apoptotic functions of Caspase-8 offer growth advantage in these cancer types and have, therefore, gained renewed interest in the recent years. In light of these reasons, a number of therapeutic approaches have been employed, with the intent of targeting pro-Caspase-8 in cancer cells. In this review, we would attempt to discuss - the classic roles of Caspase-8 in initiating apoptosis; it's non-apoptotic functions; it's the clinical significance in different cancer types; and the therapeutic applications exploiting the ability of pro-Caspase-8 to regulate various cellular functions.

Fas Ligand (FasL) in Association with Tumor-Infiltrating Lymphocytes (TILs) in Early Stage Cervical Cancer

OBJECTIVE

To date, little is known about the roles of FasL and TILs in cervical cancer. This study aims to determine the correlation between FasL expression and TILs presence in cervical cancer.

METHODS

In this study, we analysed the FasL and TIL presence in 32 squamous cell carcinoma or adenocarcinoma that were obtained from early stage (≤ IIA2) cervical cancer patients using immunohistochemistry. The level of FasL and TIL was assessed qualitatively, and then quantified with the H-Score system.

RESULTS

Most of the patients were between 30 to 50 years old (59,4%), and had never taken pap smear examination before (96,9%). Based on the Pearson analysis of FasL and TIL presence, we found that FasL was inversely correlated with CD45 or TIL number when the level of FasL is above 140 and the CD45 is below 160. Based on Chi-Square test of FasL and TIL classification, there was a nine-fold odds ratio (OR) of lower TILs classification in high expression of FasL classification (OR 9, p=0.01).

CONCLUSION

An inverse correlation between FasL expression and TILs level, that might indicate FasL-induced TILs apoptosis in tumor tissue, was observed. The strong inverse correlation between FasL and TILs presence showed some insight about the interactions between cancer cells and its surroundings inside of the cervical cancer tissue. This might also be further developed to tailor a prognostic marker that can predict the outcome of therapy in patients, not only in cervical cancer, but generally in all cancer.

New benzenesulfonamide scaffold-based cytotoxic agents: Design, synthesis, cell viability, apoptotic activity and radioactive tracing studies

A new series of thiazolidinone (5a-g), thiazinone (9a-g) and dithiazepinone (9a-g) heterocycles bearing a benzenesulfonamide scaffold was synthesized. Cytotoxicity of these derivatives was assessed against MCF-7, HepG2, HCT-116 and A549 cancer cell lines and activity was compared to the known cytotoxic agents doxorubicin and 5-FU where the most active compounds displayed better to nearly similar IC50 values to the reference compounds. For assessing selectivity, the most active derivatives against MCF-7, 5b, 5c and 5e, were also assessed against the normal breast cell line MCF-10 A where they demonstrated high selective cytotoxicity to cancerous cells over that to normal cells. Further, the effect of the most active compounds 5b-e on MCF-7 and HepG2 cell cycle phase distribution was assessed and the tested sulfonamide derivatives were found to induce accumulation of cells in the <2n phase. To further confirm apoptosis induction, caspase 8 and 9 levels in MCF-7 and HepG2 were evaluated before and after treatment with compounds 5b-e and were found to be significantly higher after exposure to the test agents. Since 5c was the most active, its effect on the cell cycle regulation was confirmed where it showed inhibition of the CDK2/cyclin E1. Finally, in vivo biodistribution study using radioiodinated-5c revealed a significant uptake and targeting ability into solid tumor in a xenograft mouse model.

Targeting apoptotic caspases in cancer

Members of the caspase family of proteases play essential roles in the initiation and execution of apoptosis. These caspases are divided into two groups: the initiator caspases (caspase-2, -8, -9 and -10), which are the first to be activated in response to a signal, and the executioner caspases (caspase-3, -6, and -7) that carry out the demolition phase of apoptosis. Many conventional cancer therapies induce apoptosis to remove the cancer cell by engaging these caspases indirectly. Newer therapeutic applications have been designed, including those that specifically activate individual caspases using gene therapy approaches and small molecules that repress natural inhibitors of caspases already present in the cell. For such approaches to have maximal clinical efficacy, emerging insights into non-apoptotic roles of these caspases need to be considered. This review will discuss the roles of caspases as safeguards against cancer in the context of the advantages and potential limitations of targeting apoptotic caspases for the treatment of cancer.

Role of cholinergic agents in proliferation and caspase activity of hemin-induced erythroid differentiated K562 cells

Background: Muscarinic receptors have many functions in the cells and tissues. Acetylcholine (ACh) plays an important role in cellular physiology. ACh also acts at the different parts of the central nervous system and nonneuronal cells. Cholinergic receptors also have different functions in many cell types and tissues. Caspases (cysteine aspartic proteases and cysteine aspartases) are cysteine dependent aspartate-specific proteases. They are an important role in necrosis and cell death and inflammation signaling pathways. They are also the primary mediators of apoptosis. During apoptosis, different caspase types participate in different functions. We have previously shown that carbachol (CCh) inhibits K562 cell proliferation. This study was performed to investigate the anti-tumor efficacy of cholinergic drugs in hemin-induced erythroid differentiated K562 cells. The aim of this study was to address the mechanism of cholinergic drugs on hemin-induced erythroid differentiated K562 cell proliferation and caspase activities. We detected M₃ muscarinic receptor expression in erythroid differentiated K562 cell line.Methods: K562 cells were differentiated with hemin (50 μM). The expression of the M₃ muscarinic receptor was detected by the western blotting technique. Erythroid differentiated K562 cells treated with CCh (100 μM). After 24 and 48 h, cells were counted by BrdU cell proliferation kit. Caspase 3,8, and 9 activities were measured by enzyme-linked immunosorbent assay (ELISA) kits according to the manufacturer's instructions.Results: Erythroid differentiated K562 cell proliferation was not significantly increased after CCh treatment. In the meantime, caspases 8 and 9 activities in erythroid differentiated K562 cell line was significantly higher than undifferentiated K562 cells (p < .05).

Recent Advances in Apoptosis: THE Role of Hydrazones

The process of programmed cell death in higher eukaryotes (apoptosis), is generally characterized by distinct morphological characteristics and energy-dependent biochemical mechanisms. Apoptosis is considered as a vital component of various processes including normal cell turnover, proper development and functioning of the immune system, hormone-dependent atrophy, embryonic development and chemical-induced cell death. Apoptosis seems to play an important key role in the progression of several human diseases like Alzheimer's disease, Parkinson's disease and many types of cancer. Promotion of apoptosis may be a good approach for the prevention of cancer cell proliferation. In early studies, antitumor compounds have been found to induce the apoptotic process in tumor cells. On the other hand, several hydrazones were reported to have lower toxicity than hydrazides due to the blockage of -NH2 group. Therefore, the design of hydrazones that activate and promote apoptosis is an attractive strategy for the discovery and development of potential anticancer agents. The aim of this review is to provide a general overview of current knowledge and the connection between apoptosis and hydrazone. It is also the guide for the apoptotic activities of new hydrazone derivatives.

Destined to Die: Apoptosis and Pediatric Cancers

Apoptosis (programmed cell death) is a systematic and coordinated cellular process that occurs in physiological and pathophysiological conditions. Sidestepping or resisting apoptosis is a distinct characteristic of human cancers including childhood malignancies. This review dissects the apoptosis pathways implicated in pediatric tumors. Understanding these pathways not only unraveled key molecules that may serve as potential targets for drug discovery, but also molecular nodes that integrate with other signaling networks involved in processes such as development. This review presents current knowledge of the complex regulatory system that governs apoptosis with respect to other processes in pediatric cancers, so that fresh insights may be derived regarding treatment resistance or for more effective treatment options.

Gene-Specific Targeting of DNA Methylation in the Mammalian Genome

DNA methylation is the most widely-studied epigenetic modification, playing a critical role in the regulation of gene expression. Dysregulation of DNA methylation is implicated in the pathogenesis of numerous diseases. For example, aberrant DNA methylation in promoter regions of tumor-suppressor genes has been strongly associated with the development and progression of many different tumors. Accordingly, technologies designed to manipulate DNA methylation at specific genomic loci are very important, especially in the context of cancer therapy. Traditionally, epigenomic editing technologies have centered around zinc finger proteins (ZFP)- and transcription activator-like effector protein (TALE)-based targeting. More recently, however, the emergence of clustered regulatory interspaced short palindromic repeats (CRISPR)-deactivated Cas9 (dCas9)-based editing systems have shown to be a more specific and efficient method for the targeted manipulation of DNA methylation. Here, we describe the regulation of the DNA methylome, its significance in cancer and the current state of locus-specific editing technologies for altering DNA methylation.

FDA-approved drug screen identifies proteasome as a synthetic lethal target in MYC-driven neuroblastoma

MYCN amplification in neuroblastoma predicts poor prognosis and resistance to therapy. Yet pharmacological strategies of direct MYC inhibition remain unsuccessful due to its "undruggable" protein structure. We herein developed a synthetic lethal screen against MYCN-amplified neuroblastomas using clinically approved therapeutic reagents. We performed a high-throughput screen, from a library of 938 FDA-approved drugs, for candidates that elicit synthetic lethal effects in MYC-driven neuroblastoma cells. The proteasome inhibitors, which are FDA approved for the first-line treatment of multiple myeloma, emerge as top hits to elicit MYC-mediated synthetic lethality. Proteasome inhibition activates the PERK-eIF2α-ATF4 axis in MYC-transformed cells and induces BAX-mediated apoptosis through ATF4-dependent NOXA and TRIB3 induction. A combination screen reveals the proteasome inhibitor bortezomib (BTZ) and the histone deacetylase (HDAC) inhibitor vorinostat (SAHA) concertedly induce dramatic cell death in part through synergistic activation of BAX. This combination causes marked tumor suppression in vivo, supporting dual proteasome/HDAC inhibition as a potential therapeutic approach for MYC-driven cancers. This FDA-approved drug screen with in vivo validation thus provides a rationale for clinical evaluation of bortezomib, alone or in combination with vorinostat, in MYC-driven neuroblastoma patients.

TNFR1 and TNFR2 in the Control of the Life and Death Balance of Macrophages

Macrophages stand in the first line of defense against a variety of pathogens but are also involved in the maintenance of tissue homeostasis. To fulfill their functions macrophages sense a broad range of pathogen- and damage-associated molecular patterns (PAMPs/DAMPs) by plasma membrane and intracellular pattern recognition receptors (PRRs). Intriguingly, the overwhelming majority of PPRs trigger the production of the pleiotropic cytokine tumor necrosis factor-alpha (TNF). TNF affects almost any type of cell including macrophages themselves. TNF promotes the inflammatory activity of macrophages but also controls macrophage survival and death. TNF exerts its activities by stimulation of two different types of receptors, TNF receptor-1 (TNFR1) and TNFR2, which are both expressed by macrophages. The two TNF receptor types trigger distinct and common signaling pathways that can work in an interconnected manner. Based on a brief general description of major TNF receptor-associated signaling pathways, we focus in this review on research of recent years that revealed insights into the molecular mechanisms how the TNFR1-TNFR2 signaling network controls the life and death balance of macrophages. In particular, we discuss how the TNFR1-TNFR2 signaling network is integrated into PRR signaling.

Direct Inhibition of IRF-Dependent Transcriptional Regulatory Mechanisms Associated With Disease

Interferon regulatory factors (IRFs) are a family of homologous proteins that regulate the transcription of interferons (IFNs) and IFN-induced gene expression. As such they are important modulating proteins in the Toll-like receptor (TLR) and IFN signaling pathways, which are vital elements of the innate immune system. IRFs have a multi-domain structure, with the N-terminal part acting as a DNA binding domain (DBD) that recognizes a DNA-binding motif similar to the IFN-stimulated response element (ISRE). The C-terminal part contains the IRF-association domain (IAD), with which they can self-associate, bind to IRF family members or interact with other transcription factors. This complex formation is crucial for DNA binding and the commencing of target-gene expression. IRFs bind DNA and exert their activating potential as homo or heterodimers with other IRFs. Moreover, they can form complexes (e.g., with Signal transducers and activators of transcription, STATs) and collaborate with other co-acting transcription factors such as Nuclear factor-κB (NF-κB) and PU.1. In time, more of these IRF co-activating mechanisms have been discovered, which may play a key role in the pathogenesis of many diseases, such as acute and chronic inflammation, autoimmune diseases, and cancer. Detailed knowledge of IRFs structure and activating mechanisms predisposes IRFs as potential targets for inhibition in therapeutic strategies connected to numerous immune system-originated diseases. Until now only indirect IRF modulation has been studied in terms of antiviral response regulation and cancer treatment, using mainly antisense oligonucleotides and siRNA knockdown strategies. However, none of these approaches so far entered clinical trials. Moreover, no direct IRF-inhibitory strategies have been reported. In this review, we summarize current knowledge of the different IRF-mediated transcriptional regulatory mechanisms and how they reflect the diverse functions of IRFs in homeostasis and in TLR and IFN signaling. Moreover, we present IRFs as promising inhibitory targets and propose a novel direct IRF-modulating strategy employing a pipeline approach that combines comparative in silico docking to the IRF-DBD with in vitro validation of IRF inhibition. We hypothesize that our methodology will enable the efficient identification of IRF-specific and pan-IRF inhibitors that can be used for the treatment of IRF-dependent disorders and malignancies.

Supramolecular Complexes in Cell Death and Inflammation and Their Regulation by Autophagy

Signaling activation is a tightly regulated process involving myriad posttranslational modifications such as phosphorylation/dephosphorylation, ubiquitylation/deubiquitylation, proteolytical cleavage events as well as translocation of proteins to new compartments within the cell. In addition to each of these events potentially regulating individual proteins, the assembly of very large supramolecular complexes has emerged as a common theme in signal transduction and is now known to regulate many signaling events. This is particularly evident in pathways regulating both inflammation and cell death/survival. Regulation of the assembly and silencing of these complexes plays important roles in immune signaling and inflammation and the fate of cells to either die or survive. Here we will give a summary of some of the better studied supramolecular complexes involved in inflammation and cell death, particularly with a focus on diseases caused by their autoactivation and the role autophagy either plays or may be playing in their regulation.

RIPK1 and Caspase-8 Ensure Chromosome Stability Independently of Their Role in Cell Death and Inflammation

Receptor-interacting protein kinase (RIPK) 1 functions as a key mediator of tissue homeostasis via formation of Caspase-8 activating ripoptosome complexes, positively and negatively regulating apoptosis, necroptosis, and inflammation. Here, we report an unanticipated cell-death- and inflammation-independent function of RIPK1 and Caspase-8, promoting faithful chromosome alignment in mitosis and thereby ensuring genome stability. We find that ripoptosome complexes progressively form as cells enter mitosis, peaking at metaphase and disassembling as cells exit mitosis. Genetic deletion and mitosis-specific inhibition of Ripk1 or Caspase-8 results in chromosome alignment defects independently of MLKL. We found that Polo-like kinase 1 (PLK1) is recruited into mitotic ripoptosomes, where PLK1's activity is controlled via RIPK1-dependent recruitment and Caspase-8-mediated cleavage. A fine balance of ripoptosome assembly is required as deregulated ripoptosome activity modulates PLK1-dependent phosphorylation of downstream effectors, such as BUBR1. Our data suggest that ripoptosome-mediated regulation of PLK1 contributes to faithful chromosome segregation during mitosis.