The life and death of immune cell types: the role of BCL-2 anti-apoptotic molecules

Identification of apoptosis-immune-related gene signature and construction of diagnostic model for sepsis based on single-cell sequencing and bulk transcriptome analysis

Introduction

Sepsis leads to multi-organ dysfunction due to disorders of the host response to infections, which makes diagnosis and prognosis challenging. Apoptosis, a classic programmed cell death, contributes to the pathogenesis of various diseases. However, there is much uncertainty about its mechanism in sepsis.

Methods

Three sepsis gene expression profiles (GSE65682, GSE13904, and GSE26378) were downloaded from the Gene Expression Omnibus database. Apoptosis-related genes were obtained from the Kyoto Encyclopedia of Genes and Genomes Pathway database. We utilized LASSO regression and SVM-RFE algorithms to identify characteristic genes associated with sepsis. CIBERSORT and single cell sequencing analysis were employed to explore the potential relationship between hub genes and immune cell infiltration. The diagnostic capability of hub genes was validated across multiple external datasets. Subsequently, the animal sepsis model was established to assess the expression levels of hub genes in distinct target organs through RT-qPCR and Immunohistochemistry analysis.

Results

We identified 11 apoptosis-related genes as characteristic diagnostic markers for sepsis: CASP8, VDAC2, CHMP1A, CHMP5, FASLG, IFNAR1, JAK1, JAK3, STAT4, IRF9, and BCL2. Subsequently, a prognostic model was constructed using LASSO regression with BCL2, FASLG, IRF9 and JAK3 identified as hub genes. Apoptosis-related genes were closely associated with the immune response during the sepsis process. Furthermore, in the validation datasets, aside from IRF9, other hub genes demonstrated similar expression patterns and diagnostic abilities as observed in GSE65682 dataset. In the mouse model, the expression differences of hub genes between sepsis and control group revealed the potential impacts on sepsis-induced organ injury.

Conclusion

The current findings indicated the participant of apoptosis in sepsis, and apoptosis-related differentially expressed genes could be used for diagnosis biomarkers. BCL2, FASLG, IRF9 and JAK3 might be key regulatory genes affecting apoptosis in sepsis. Our findings provided a novel aspect for further exploration of the pathological mechanisms in sepsis.

Kisspeptin-10 Improves Testicular Redox Status but Does Not Alter the Unfolded Protein Response (UPR) That Is Downregulated by Hypothyroidism in a Rat Model

Hypothyroidism compromises the testicular redox status and is associated with reduced sperm quality and infertility in men. In this regard, studies have demonstrated the antioxidant potential of kisspeptin in reproductive and metabolic diseases. In this study, we evaluate the effects of kisspeptin-10 (Kp10) on the testicular redox, as well as mediators of the unfolded protein response (UPR) in adult rats with hypothyroidism. Adult male Wistar rats were randomly separated into the Control (n = 15), Hypo (n = 13) and Hypo + Kp10 (n = 14) groups, and hypothyroidism was induced with 6-propyl-2-thiouracil (PTU) for three months. In the last month, half of the hypothyroid animals received Kp10. Testis samples were collected for enzymatic, immunohistochemical and/or gene evaluation of mediators of oxidative stress (TBARs, lipid hydroperoxides (LOOH), ROS, peroxynitrite, SOD, CAT and GPX), endoplasmic reticulum stress (GRP78, ATF6, PERK, CHOP, HO-1 and sXBP1) and antiapoptocytes (BCL-2). Hypothyroidism increased apoptosis index, TBARS and LOOH concentrations, and reduced testicular gene expression of Sod1, Sod2 and Gpx1, as well as the expression of Grp78, Atf6, Ho1 and Chop. Treatment with Kp10, in turn, reduced testicular apoptosis and the production of peroxynitrite, while increased SOD1 and GPX ½ expression, and enzymatic activity of CAT, but did not affect the lower expression of UPR mediators caused by hypothyroidism. This study demonstrated that hypothyroidism causes oxidative stress and dysregulated the UPR pathway in rat testes and that, although Kp10 does not influence the low expression of UPR mediators, it improves the testicular redox status, configuring it as an important antioxidant factor in situations of thyroid dysfunction.

A Successful Bridge Therapy Combining Hypomethylating Agents with Venetoclax for Adult Patients with Newly Diagnosed or Relapsed/Refractory Acute Myeloid Leukemia

Recently, the combination of VEN-HMA has been shown to achieve durable responses in patients with both newly diagnosed (ND) and R/R-AML. We retrospectively evaluated the post-allo-HCT outcomes of 50 patients who received VEN-HMA therapy. In total, 10 were ND and 40 were R/R and, at the time of HCT, the median age was 53 years. In the ND- and R/R-AML groups, the percentage of patients who achieved CR/CRi or MLFS was 90% and 92.5%, respectively. In all, after a median follow-up of 13.7 months, the probabilities of overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM) at 1 year were 63.7%, 59.3%, 28.5%, and 12.2%, respectively. In addition, the cumulative incidences of grade II–IV acute graft-versus-host disease (GVHD) and moderate–severe chronic GVHD at 1 year were 28.4% and 37.4%, respectively. In multivariate analysis, the factors associated with a statistically significant impact on OS were VEN-HMA cycle (p = 0.021), ELN risk group (p = 0.041), and the response to VEN-HMA therapy before allo-HCT (p = 0.003). Although 80% of our patients had R/R-AML and 30% underwent a second allo-HCT, our data still suggest that allo-HCT following VEN-HMA therapy is a safe and effective treatment option.

Effects of tobacco on the DNA of smokers and non-smokers affected by OSCC: systematic review and meta-analysis

Scientific evidence about genetic and molecular changes in oral squamous cell carcinoma (OSCC) among smokers and non-smokers is inconclusive. This systematic review and meta-analysis assessed the effects of tobacco on the DNA of individuals with OSCC based on protein mutations. Electronic searches were conducted on PubMed, Ovid, Web of Science, and Scopus to identify observational studies published up to January/2022. The Joanna Briggs Institute tool was used for the critical appraisal of studies. The certainty of the evidence was evaluated. Twenty-three studies assessing 4,060 individuals (2,967 smokers vs. 1,093 non-smokers) were included in this review. Fifteen groups of proteins/genes were investigated. Analysis of the quality of articles revealed low risk of bias in most studies. The certainty of the evidence was very low. The meta-analysis confirmed no significant difference between smokers and non-smokers with respect to damage to GSTM1 (OR: 0.60; 95%CI: 0.30-1.18), GSTT1 (OR: 1.18; 95%CI:0.49-2.83), hydrolase proteins (Ku70 and Ku80) (OR: 0.74; 95%CI: 0.18-3.05), and transferase proteins (GSTM1, GSTT1, GSTM3) (OR: 0.74; 95%CI: 0.47-1.18). Most of the studies included showed that smokers are more likely to exhibit genetic instability. However, the meta-analysis revealed that smokers do not necessarily have more genetic alterations in the DNA than non-smokers.

Adapted to Survive: Targeting Cancer Cells with BH3 Mimetics

A hallmark of cancer is cell death evasion, underlying suboptimal responses to chemotherapy, targeted agents, and immunotherapies. The approval of the antiapoptotic BCL2 antagonist venetoclax has finally validated the potential of targeting apoptotic pathways in patients with cancer. Nevertheless, pharmacologic modulators of cell death have shown markedly varied responses in preclinical and clinical studies. Here, we review emerging concepts in the use of this class of therapies. Building on these observations, we propose that treatment-induced changes in apoptotic dependency, rather than pretreatment dependencies, will need to be recognized and targeted to realize the precise deployment of these new pharmacologic agents.

SIGNIFICANCE

Targeting antiapoptotic family members has proven efficacious and tolerable in some cancers, but responses are infrequent, particularly for patients with solid tumors. Biomarkers to aid patient selection have been lacking. Precision functional approaches that overcome adaptive resistance to these compounds could drive durable responses to chemotherapy, targeted therapy, and immunotherapies.

Treatment with ribociclib shows favourable immunomodulatory effects in patients with hormone receptor-positive breast cancer-findings from the RIBECCA trial

BACKGROUND

Inhibitors of the cyclin-dependent kinases 4 and 6 (CDK4/6i) have significantly improved clinical outcomes in patients with advanced hormone receptor-positive (HR+) breast cancer and have demonstrated favourable antitumour immune responses in preclinical studies.

METHODS

Here, we investigated peripheral immune responses to ribociclib in patients with metastatic HR+ breast cancer as a preplanned exploratory subanalysis of the RIBECCA trial (NCT03096847). Peripheral blood mononuclear cells were subjected to immune cell profiling, gene expression analysis of immune-related signatures, and deep T cell receptor profiling before treatment started and after 12 weeks of treatment with ribociclib.

RESULTS

Gene expression analysis revealed an upregulation of signatures associated with an activated adaptive immune system and a decrease in immunosuppressive cytokine signalling during treatment with ribociclib. Profiling of peripheral immune cell subpopulations showed a decrease in Treg cell frequencies, which was associated with treatment response. Furthermore, induction of CD4+ naive T cells could be seen, whereas effector and memory T cell populations remained largely unchanged. Correspondingly, T cell repertoire diversity remained mostly unchanged during treatment, although an increase in clonality could be observed in single patients.

CONCLUSIONS

We show that treatment with ribociclib has significant effects on the peripheral innate and adaptive immune response in patients with HR+ breast cancer. Our data suggest that these effects lead to an activation of an already existing immune response rather than a de novo induction and make a strong case for future combination strategies of CDK4/6i with immunotherapies to enhance the adaptive immune response in HR+ breast cancer.

Targeting the CCL2/CCR2 Axis in Cancer Immunotherapy: One Stone, Three Birds?

CCR2 is predominantly expressed by monocytes/macrophages with strong proinflammatory functions, prompting the development of CCR2 antagonists to dampen unwanted immune responses in inflammatory and autoimmune diseases. Paradoxically, CCR2-expressing monocytes/macrophages, particularly in tumor microenvironments, can be strongly immunosuppressive. Thus, targeting the recruitment of immunosuppressive monocytes/macrophages to tumors by CCR2 antagonism has recently been investigated as a strategy to modify the tumor microenvironment and enhance anti-tumor immunity. We present here that beneficial effects of CCR2 antagonism in the tumor setting extend beyond blocking chemotaxis of suppressive myeloid cells. Signaling within the CCL2/CCR2 axis shows underappreciated effects on myeloid cell survival and function polarization. Apart from myeloid cells, T cells are also known to express CCR2. Nevertheless, tissue homing of Treg cells among T cell populations is preferentially affected by CCR2 deficiency. Further, CCR2 signaling also directly enhances Treg functional potency. Thus, although Tregs are not the sole type of T cells expressing CCR2, the net outcome of CCR2 antagonism in T cells favors the anti-tumor arm of immune responses. Finally, the CCL2/CCR2 axis directly contributes to survival/growth and invasion/metastasis of many types of tumors bearing CCR2. Together, CCR2 links to two main types of suppressive immune cells by multiple mechanisms. Such a CCR2-assoicated immunosuppressive network is further entangled with paracrine and autocrine CCR2 signaling of tumor cells. Strategies to target CCL2/CCR2 axis as cancer therapy in the view of three types of CCR2-expessing cells in tumor microenvironment are discussed.

Venetoclax imparts distinct cell death sensitivity and adaptivity patterns in T cells

BH3 mimetics are increasingly used as anti-cancer therapeutics either alone or in conjunction with other chemotherapies. However, mounting evidence has also demonstrated that BH3 mimetics modulate varied amounts of apoptotic signaling in healthy immune populations. In order to maximize their clinical potential, it will be essential to understand how BH3 mimetics affect discrete immune populations and to determine how BH3 mimetic pressure causes immune system adaptation. Here we focus on the BCL-2 specific inhibitor venetoclax (ABT-199) and its effects following short-term and long-term BCL-2 blockade on T cell subsets. Seven day "short-term" ex vivo and in vivo BCL-2 inhibition led to divergent cell death sensitivity patterns in CD8⁺ T cells, CD4⁺ T cells, and Tregs resulting in shifting of global T cell populations towards a more memory T cell state with increased expression of BCL-2, BCL-X_L, and MCL-1. However, twenty-eight day "long-term" BCL-2 blockade following T cell-depleted bone marrow transplantation did not lead to changes in the global T cell landscape. Despite the lack of changes in T cell proportions, animals treated with venetoclax developed CD8⁺ and CD4⁺ T cells with high levels of BCL-2 and were more resistant to apoptotic stimuli following expansion post-transplant. Further, we demonstrate through RNA profiling that T cells adapt while under BCL-2 blockade post-transplant and develop a more activated genotype. Taken together, these data emphasize the importance of evaluating how BH3 mimetics affect the immune system in different treatment modalities and disease contexts and suggest that venetoclax should be further explored as an immunomodulatory compound.

Can the New and Old Drugs Exert an Immunomodulatory Effect in Acute Myeloid Leukemia?

Simple Summary

The advent of novel immunotherapeutic strategies has revealed the importance of immune dysregulation and of a tolerogenic microenvironment for acute myeloid leukemia (AML) fitness. We reviewed the “off-target” effects on the immune system of different drugs used in the treatment of AML to explore the advantages of this unexpected interaction.

Abstract

Acute myeloid leukemia (AML) is considered an immune-suppressive neoplasm capable of evading immune surveillance through cellular and environmental players. Increasing knowledge of the immune system (IS) status at diagnosis seems to suggest ever more attention of the crosstalk between the leukemic clone and its immunologic counterpart. During the last years, the advent of novel immunotherapeutic strategies has revealed the importance of immune dysregulation and suppression for leukemia fitness. Considering all these premises, we reviewed the “off-target” effects on the IS of different drugs used in the treatment of AML, focusing on the main advantages of this interaction. The data reported support the idea that a successful therapeutic strategy should consider tailored approaches for performing leukemia eradication by both direct blasts killing and the engagement of the IS.

Importance of Bcl-2-family proteins in murine hematopoietic progenitor and early B cells

Mitochondrial apoptosis regulates survival and development of hematopoietic cells. Prominent roles of some Bcl-2-family members in this regulation have been established, for instance for pro-apoptotic Bim and anti-apoptotic Mcl-1. Additional, mostly smaller roles are known for other Bcl-2-members but it has been extremely difficult to obtain a comprehensive picture of the regulation of mitochondrial apoptosis in hematopoietic cells by Bcl-2-family proteins. We here use a system of mouse ‘conditionally immortalized’ lymphoid-primed hematopoietic progenitor (LMPP) cells that can be differentiated in vitro to pro-B cells, to analyze the importance of these proteins in cell survival. We established cells deficient in Bim, Noxa, Bim/Noxa, Bim/Puma, Bim/Bmf, Bax, Bak or Bax/Bak and use specific inhibitors of Bcl-2, Bcl-X_L and Mcl-1 to assess their importance. In progenitor (LMPP) cells, we found an important role of Noxa, alone and together with Bim. Cell death induced by inhibition of Bcl-2 and Bcl-X_L entirely depended on Bim and could be implemented by Bax and by Bak. Inhibition of Mcl-1 caused apoptosis that was independent of Bim but strongly depended on Noxa and was completely prevented by the absence of Bax; small amounts of anti-apoptotic proteins were co-immunoprecipitated with Bim. During differentiation to pro-B cells, substantial changes in the expression of Bcl-2-family proteins were seen, and Bcl-2, Bcl-X_L and Mcl-1 were all partially in complexes with Bim. In differentiated cells, Noxa appeared to have lost all importance while the loss of Bim and Puma provided protection. The results strongly suggest that the main role of Bim in these hematopoietic cells is the neutralization of Mcl-1, identify a number of likely molecular events during the maintenance of survival and the induction of apoptosis in mouse hematopoietic progenitor cells, and provide data on the regulation of expression and importance of these proteins during differentiation along the B cell lineage.

BCL-XL antagonism selectively reduces neutrophil life span within inflamed tissues without causing neutropenia

Neutrophils help to clear pathogens and cellular debris, but can also cause collateral damage within inflamed tissues. Prolonged neutrophil residency within an inflammatory niche can exacerbate tissue pathology. Using both genetic and pharmacological approaches, we show that BCL-XL is required for the persistence of neutrophils within inflammatory sites in mice. We demonstrate that a selective BCL-XL inhibitor (A-1331852) has therapeutic potential by causing apoptosis in inflammatory human neutrophils ex vivo. Moreover, in murine models of acute and chronic inflammatory disease, it reduced inflammatory neutrophil numbers and ameliorated tissue pathology. In contrast, there was minimal effect on circulating neutrophils. Thus, we show a differential survival requirement in activated neutrophils for BCL-XL and reveal a new therapeutic approach to neutrophil-mediated diseases.

Aberrant Bcl-x splicing in cancer: from molecular mechanism to therapeutic modulation

Bcl-x pre-mRNA splicing serves as a typical example to study the impact of alternative splicing in the modulation of cell death. Dysregulation of Bcl-x apoptotic isoforms caused by precarious equilibrium splicing is implicated in genesis and development of multiple human diseases, especially cancers. Exploring the mechanism of Bcl-x splicing and regulation has provided insight into the development of drugs that could contribute to sensitivity of cancer cells to death. On this basis, we review the multiple splicing patterns and structural characteristics of Bcl-x. Additionally, we outline the cis-regulatory elements, trans-acting factors as well as epigenetic modifications involved in the splicing regulation of Bcl-x. Furthermore, this review highlights aberrant splicing of Bcl-x involved in apoptosis evade, autophagy, metastasis, and therapy resistance of various cancer cells. Last, emphasis is given to the clinical role of targeting Bcl-x splicing correction in human cancer based on the splice-switching oligonucleotides, small molecular modulators and BH3 mimetics. Thus, it is highlighting significance of aberrant splicing isoforms of Bcl-x as targets for cancer therapy.

Structure-Guided Development of Potent Benzoylurea Inhibitors of BCL-XL and BCL-2

The BCL-2 family of proteins (including the prosurvival proteins BCL-2, BCL-X_L, and MCL-1) is an important target for the development of novel anticancer therapeutics. Despite the challenges of targeting protein-protein interaction (PPI) interfaces with small molecules, a number of inhibitors (called BH3 mimetics) have entered the clinic and the BCL-2 inhibitor, ABT-199/venetoclax, is already proving transformative. For BCL-X_L, new validated chemical series are desirable. Here, we outline the crystallography-guided development of a structurally distinct series of BCL-X_L/BCL-2 inhibitors based on a benzoylurea scaffold, originally proposed as α-helix mimetics. We describe structure-guided exploration of a cryptic "p5" pocket identified in BCL-X_L. This work yields novel inhibitors with submicromolar binding, with marked selectivity toward BCL-X_L. Extension into the hydrophobic p2 pocket yielded the most potent inhibitor in the series, binding strongly to BCL-X_L and BCL-2 (nanomolar-range half-maximal inhibitory concentration (IC₅₀)) and displaying mechanism-based killing in cells engineered to depend on BCL-X_L for survival.

Susceptibility of multiple myeloma to B-cell lymphoma 2 family inhibitors

Multiple myeloma (MM) is a biologically complex hematological disorder defined by the clonal proliferation of malignant plasma cells producing excessive monoclonal immunoglobulin that interacts with components of the bone marrow microenvironment, resulting in the major clinical features of MM. Despite the development of numerous protocols to treat MM patients, this cancer remains currently incurable; due in part to the emergence of resistant clones, highlighting the unmet need for innovative therapeutic approaches. Accumulating evidence suggests that the survival of MM molecular subgroups depends on the expression profiles of specific subsets of anti-apoptotic B-cell lymphoma (BCL)-2 family members. This review summarizes the mechanisms underlying the anti-myeloma activities of the potent BCL-2 family protein inhibitors, individually or in combination with conventional therapeutic options, and provides an overview of the strong rationale to clinically investigate such interventions for MM therapy.

Epidemiology and Clinical Characteristics of Non-Hodgkin Lymphoma in Mexico

BACKGROUND

There is no epidemiological registry in Mexico. The information about the epidemiology in our country is obtained by these types of studies, such as multicentric studies. A lot of improvements in the survival in non-Hodgkin lymphoma patients had occurred in the last 20 years. The access to treatment in these types of pathology could change the prognostic factors in Mexican Mestizos patients. The primary objective of the study was to learn what the most frequent histological varieties of non-Hodgkin lymphoma in Mexico are. The secondary objectives included clinical characteristics, treatments used, treatment response, disease-free survival and overall survival.

METHODS

A retrospective, descriptive study of consecutive cases was carried out in 14 hospitals across 14 Mexican states with patients diagnosed with non-Hodgkin lymphoma using the World Health Organization (WHO) 2008 criteria. Inclusion criteria included: ≥ 18 years of age, male or female, any clinical stage at diagnosis, who had received any chemotherapy regimen, with a known outcome. Descriptive statistics was performed for all variables, and survival was assessed using Kaplan-Meier curves.

RESULTS

Totally, 609 patients were enrolled, of which 545 were B-cell lymphomas and 64 were T-cell lymphomas. Median ages were 61 and 50, respectively. B-cell lymphomas were more common in males with 52.1%, and 65.5% of T-cell lymphomas occurred in females. For B-cell lymphomas, the two most frequent histological subtypes were diffuse large B-cell lymphoma in 63.9%, followed by follicular lymphoma at 18%. Meanwhile, 50% of T-cell lymphomas were of the T/natural killer (NK) subtype, and 87.1% of the patients received a CHOP-like regimen. Radiotherapy was given to 31% of B-cell Lymphomas and 46.9% of T-cell lymphomas. Overall survival at 9 years was 84.6% for B-cell lymphomas, and 73.4% for T-cell lymphomas.

CONCLUSIONS

Diffuse large B-cell lymphoma constitutes the most frequent subtype for B-cell lymphomas in Mexico. The most frequent T-cell lymphoma is the NK/T histological subtype.

Loss of BIM in T cells results in BCL-2 family BH3-member compensation but incomplete cell death sensitivity normalization

BIM is the master BH3-only BCL-2 family regulator of lymphocyte survival. To understand how long-term loss of BIM affects apoptotic resistance in T cells we studied animals with T cell-specific deletion of Bim. Unlike CD19^CREBim^fl/fl animals, LCK^CREBim^fl/fl mice have pronounced early lymphocytosis followed by normalization of lymphocyte counts over time. This normalization occurred in mature T cells, as thymocyte development and apoptotic sensitivity remained abnormal in LCK^CREBim^fl/fl mice. T cells from aged mice experienced normalization of their absolute cell numbers and responses against various apoptotic stimuli. mRNA expression levels of BCL-2 family proteins in CD4⁺ and CD8⁺ T cells from young and old mice revealed upregulation of several BH3-only proteins, including Puma, Noxa, and Bmf. Despite upregulation of various BH3 proteins, there were no differences in anti-apoptotic BCL-2 protein dependency in these cells. However, T cells had continued resistance to direct BIM BH3-induced mitochondrial depolarization. This study further highlights the importance of BIM in cell death maintenance in T cells and provides new insight into the dynamism underlying BH3-only regulation of T cell homeostasis versus induced cell death and suggests that CD4⁺ and CD8⁺ T cells compensate differently in response to loss of Bim.

BH3 Mimetics in AML Therapy: Death and Beyond?

B cell lymphoma 2 (BCL2) homology domain 3 (BH3) mimetics are targeted therapeutic agents that allow response prediction and patient stratification. BH3 mimetics are prototypical activators of the mitochondrial death program in cancer. They emerged as important modulators of cellular mechanisms contributing to poor therapeutic responses, including cancer cell stemness, cancer-specific metabolic routes, paracrine signaling to the tumor microenvironment, and immune modulation. We present an overview of the antagonism between BH3 mimetics and antiapoptotic BCL2 proteins. We focus on acute myeloid leukemia (AML), a cancer with reduced therapeutic options that have recently been improved by BH3 mimetics.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

The Pleiotropic Effects of the GM-CSF Rheostat on Myeloid Cell Differentiation and Function: More Than a Numbers Game

Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) is a myelopoietic growth factor that has pleiotropic effects not only in promoting the differentiation of immature precursors into polymorphonuclear neutrophils (PMNs), monocytes/macrophages (MØs) and dendritic cells (DCs), but also in controlling the function of fully mature myeloid cells. This broad spectrum of GM-CSF action may elicit paradoxical outcomes-both immunostimulation and immunosuppression-in infection, inflammation, and cancer. The complexity of GM-CSF action remains to be fully unraveled. Several aspects of GM-CSF action could contribute to its diverse biological consequences. Firstly, GM-CSF as a single cytokine affects development of most myeloid cells from progenitors to mature immune cells. Secondly, GM-CSF activates JAK2/STAT5 and also activate multiple signaling modules and transcriptional factors that direct different biological processes. Thirdly, GM-CSF can be produced by different cell types including tumor cells in response to different environmental cues; thus, GM-CSF quantity can vary greatly under different pathophysiological settings. Finally, GM-CSF signaling is also fine-tuned by other less defined feedback mechanisms. In this review, we will discuss the role of GM-CSF in orchestrating the differentiation, survival, and proliferation during the generation of multiple lineages of myeloid cells (PMNs, MØs, and DCs). We will also discuss the role of GM-CSF in regulating the function of DCs and the functional polarization of MØs. We highlight how the dose of GM-CSF and corresponding signal strength acts as a rheostat to fine-tune cell fate, and thus the way GM-CSF may best be targeted for immuno-intervention in infection, inflammation and cancer.

Long non-coding RNA MYOSLID functions as a competing endogenous RNA to regulate MCL-1 expression by sponging miR-29c-3p in gastric cancer

Objective

Long non‐coding RNA (lncRNA) has become an important regulator of many human malignancies. However, the biological role and clinical significance of most lncRNA in gastric cancer (GC) remain unclear.

Methods

We investigate the biological function, mechanism of action and clinical expression of lncRNA MYOSLID in GC. First, we analysed the differential expression of lncRNA MYOSLID in GC tissues and non‐cancerous tissues by analysing the sequencing data obtained from The Cancer Genome Atlas. Subsequently, we verified that lncRNA MYOSLID regulates the proliferation and apoptosis of GC cells by acting as a ceRNA against miR‐29c‐3p. The nude mouse xenograft was used to further confirm the functional significance of lncRNA MYOSLID in vivo.

Results

We found for the first time that the expression of lncRNA MYOSLID was significantly up‐regulated in GC tissues, and the up‐regulation of lncRNA MYOSLID in GC was correlated with tumour size, AJCC stage, depth of invasion and survival time. In addition, apoptosis and growth arrest can be induced in vitro after knockdown of lncRNA MYOSLID, which inhibits tumorigenesis in mouse xenografts in vivo. Further in‐depth studies revealed that lncRNA MYOSLID acts as a ceRNA of miR‐29c‐3p, resulting in de‐repression of its downstream target gene MCL‐1.

Conclusion

The lncRNA MYOSLID‐miR‐29c‐3p‐MCL‐1 axis plays a key role in the development of GC. Our findings may provide potential new targets for the diagnosis and treatment of human GC.

Trial watch: dendritic cell vaccination for cancer immunotherapy

Dendritic- cells (DCs) have received considerable attention as potential targets for the development of anticancer vaccines. DC-based anticancer vaccination relies on patient-derived DCs pulsed with a source of tumor-associated antigens (TAAs) in the context of standardized maturation-cocktails, followed by their reinfusion. Extensive evidence has confirmed that DC-based vaccines can generate TAA-specific, cytotoxic T cells. Nonetheless, clinical efficacy of DC-based vaccines remains suboptimal, reflecting the widespread immunosuppression within tumors. Thus, clinical interest is being refocused on DC-based vaccines as combinatorial partners for T cell-targeting immunotherapies. Here, we summarize the most recent preclinical/clinical development of anticancer DC vaccination and discuss future perspectives for DC-based vaccines in immuno-oncology.

An integrated transcriptional switch at the β-selection checkpoint determines T cell survival, development and leukaemogenesis

In T cell development, a pivotal decision-making stage, termed β-selection, integrates a TCRβ checkpoint to coordinate survival, proliferation and differentiation to an αβ T cell. Here, we review how transcriptional regulation coordinates fate determination in early T cell development to enable β-selection. Errors in this transcription control can trigger T cell acute lymphoblastic leukaemia. We describe how the β-selection checkpoint goes awry in leukaemic transformation.

YY1 regulates cancer cell immune resistance by modulating PD-L1 expression

Recent advances in the treatment of various cancers have resulted in the adaptation of several novel immunotherapeutic strategies. Notably, the recent intervention through immune checkpoint inhibitors has resulted in significant clinical responses and prolongation of survival in patients with several therapy-resistant cancers (melanoma, lung, bladder, etc.). This intervention was mediated by various antibodies directed against inhibitory receptors expressed on cytotoxic T-cells or against corresponding ligands expressed on tumor cells and other cells in the tumor microenvironment (TME). However, the clinical responses were only observed in a subset of the treated patients; it was not clear why the remaining patients did not respond to checkpoint inhibitor therapies. One hypothesis stated that the levels of PD-L1 expression correlated with poor clinical responses to cell-mediated anti-tumor immunotherapy. Hence, exploring the underlying mechanisms that regulate PD-L1 expression on tumor cells is one approach to target such mechanisms to reduce PD-L1 expression and, therefore, sensitize the resistant tumor cells to respond to PD-1/PD-L1 antibody treatments. Various investigations revealed that the overexpression of the transcription factor Yin Yang 1 (YY1) in most cancers is involved in the regulation of tumor cells' resistance to cell-mediated immunotherapies. We, therefore, hypothesized that the role of YY1 in cancer immune resistance may be correlated with PD-L1 overexpression on cancer cells. This hypothesis was investigated and analysis of the reported literature revealed that several signaling crosstalk pathways exist between the regulations of both YY1 and PD-L1 expressions. Such pathways include p53, miR34a, STAT3, NF-kB, PI3K/AKT/mTOR, c-Myc, and COX-2. Noteworthy, many clinical and pre-clinical drugs have been utilized to target these above pathways in various cancers independent of their roles in the regulation of PD-L1 expression. Therefore, the direct inhibition of YY1 and/or the use of the above targeted drugs in combination with checkpoint inhibitors should result in enhancing the cell-mediated anti-tumor cell response and also reverse the resistance observed with the use of checkpoint inhibitors alone.

Emerging drug profile: Krebs cycle and cancer: IDH mutations and therapeutic implications

Mutations in IDH1 and IDH2 genes occur frequently in myeloid malignancies and certain solid tumors. IDH1 and IDH2 are enzymes that are involved in the tricarboxylic acid (TCA) cycle. Activating mutations in IDH1 and IDH2 leads to increased production of 2-hydroxygluterate and epigenetic modification, affecting cell differentiation. Small molecule inhibitors of mutated IDH1 and IDH2 have shown promising anti-cancer activity in both preclinical models and early clinical trials. Recently, enasidenib and ivosidenib, oral inhibitors of mutated IDH2 and IDH1 genes, respectively, were approved for use in relapsed or refractory acute myeloid leukemia. This review will focus on the underlying biological mechanism and clinical relevance of IDH mutations in cancer.

Programmed Cell Death in Immune Defense: Knowledge and Presumptions

Cell-culture studies are our main source of knowledge of the various forms of programmed cell death. Yet genetic perturbations of death-protein function in animal models are almost the only source of our knowledge of the physiological roles of these programs. Shortcomings in the state of knowledge acquired by these two experimental approaches are exemplified in this Perspective by reference to research on the contribution of apoptosis to lymphocyte development, a subject on which there is already much knowledge, and on the role of necroptosis in inflammation, about which information is just beginning to emerge. To address these shortcomings, there is need to find ways to verify the notions obtained through the current experimental approaches by directly monitoring death programs within specific cells in vivo.

BAFF-driven B cell hyperplasia underlies lung disease in common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency and is frequently complicated by interstitial lung disease (ILD) for which etiology is unknown and therapy inadequate.

METHODS

Medical record review implicated B cell dysregulation in CVID ILD progression. This was further studied in blood and lung samples using culture, cytometry, ELISA, and histology. Eleven CVID ILD patients were treated with rituximab and followed for 18 months.

RESULTS

Serum IgM increased in conjunction with ILD progression, a finding that reflected the extent of IgM production within B cell follicles in lung parenchyma. Targeting these pulmonary B cell follicles with rituximab ameliorated CVID ILD, but disease recurred in association with IgM elevation. Searching for a stimulus of this pulmonary B cell hyperplasia, we found B cell-activating factor (BAFF) increased in blood and lungs of progressive and post-rituximab CVID ILD patients and detected elevation of BAFF-producing monocytes in progressive ILD. This elevated BAFF interacts with naive B cells, as they are the predominant subset in progressive CVID ILD, expressing BAFF receptor (BAFF-R) within pulmonary B cell follicles and blood to promote Bcl-2 expression. Antiapoptotic Bcl-2 was linked with exclusion of apoptosis from B cell follicles in CVID ILD and increased survival of naive CVID B cells cultured with BAFF.

CONCLUSION

CVID ILD is driven by pulmonary B cell hyperplasia that is reflected by serum IgM elevation, ameliorated by rituximab, and bolstered by elevated BAFF-mediated apoptosis resistance via BAFF-R.

FUNDING

NIH, Primary Immune Deficiency Treatment Consortium, and Rare Disease Foundation.

Reprogramming factors induce proliferation and inhibit apoptosis of melanoma cells by changing the expression of particular genes

Uncontrolled proliferation and defective apoptosis are two major factors responsible for maintaining the malignant properties of melanoma cells. Our previous study demonstrated that induced expression of four reprogramming factors remodeled the phenotype of B16‑F10 mouse melanoma cells into melanoma stem cells. The present study was conducted to investigate the effect of the four Yamanaka reprogramming factors, namely Oct4, Sox2, Klf4 and c‑Myc (OSKM), on the proliferation and apoptosis of melanoma cells, and to identify the responsible molecular signals. The results identified that expression of the four reprogramming factors was highly induced by doxycycline treatment in the stable melanoma cell clone that was transfected with a plasmid expressing these factors, driven by the Tet‑On element. It was further confirmed that induced expression of these factors enhanced the proliferation and suppressed the apoptosis of the melanoma cells. In addition, induced OSKM expression increased cell proliferation, accelerated the progression of the cell cycle, and upregulated the mRNA expression levels of Janus kinase 2 (JAK2) and Cyclin‑B1. Induced expression of these factors also decreased the apoptosis, as well as upregulated B‑cell lymphoma 2 (BCL‑2) and downregulated BCL‑2‑associated X (BAX) mRNA expression levels. Taken together, the results suggested that upregulated JAK2 and Cyclin‑B1 may be responsible for the enhanced proliferation of melanoma cells, and that BCL‑2 upregulation and BAX downregulation may account for the suppressed apoptosis of these cells.

IL-21 and anti-CD40 restore Bcl-2 family protein imbalance in vitro in low-survival CD27+ B cells from CVID patients

Common variable immunodeficiency (CVID) is characterized by an abnormal B cell differentiation to memory and antibody-secreting B cells. The defective functionality of CVID patients’ B cells could be the consequence of alterations in apoptosis regulation. We studied the balance of Bcl-2 family anti-/pro-apoptotic proteins to identify molecular mechanisms that could underlie B cell survival defects in CVID. We used flow cytometry to investigate Bcl-2, Bcl-XL, Bax, and Bim expression in B cells ex vivo and after anti-CD40 or anti-BCR activation with or without IL-21, besides to spontaneous and stimulation-induced Caspase-3 activation and viable/apoptotic B cell subpopulations. We found increased basal levels of Bax and Bim in CVID B cells that correlated with low viability and high Caspase-3 activation only in CD27⁺ B cells, particularly in a subgroup of apoptosis-prone CVID (AP-CVID) patients with low peripheral B cell counts and high autoimmunity prevalence (mostly cytopenias). We detected a broad B cell defect in CVID regarding Bcl-2 and Bcl-XL induction, irrespective of the stimulus used. Therefore, peripheral CVID memory B cells are prompted to die from apoptosis due to a constitutive Bcl-2 family protein imbalance and defective protection from activation-induced apoptosis. Interestingly, anti-CD40 and IL-21 induced normal and even higher levels of Bcl-XL, respectively, in CD27⁺ B cells from AP-CVID, which was accompanied by cell viability increase. Thus low-survival memory B cells from AP-CVID can overcome their cell death regulation defects through pro-survival signals provided by T cells. In conclusion, we identify apoptosis regulation defects as disease-contributing factors in CVID. B cell counts and case history of cytopenias might be useful to predict positive responses to therapeutic approaches targeting T-dependent signaling pathways.

Protein phosphatase 2A mediates JS-K-induced apoptosis by affecting Bcl-2 family proteins in human hepatocellular carcinoma HepG2 cells

Protein phosphatase 2A (PP2A) is an important enzyme within various signal transduction pathways. The present study was investigated PP2A mediates JS-K-induced apoptosis by affecting Bcl-2 family protein. JS-K showed diverse inhibitory effects in five HCC cell lines, especially HepG2 cells. JS-K caused a dose- and time-dependent reduction in cell viability and increased in levels of LDH release. Meanwhile, JS-K- induced apoptosis was characterized by mitochondrial membrane potential reduction, Hoechst 33342⁺ /PI⁺ dual staining, release of cytochrome c (Cyt c), and activation of cleaved caspase-9/3. Moreover, JS-K-treatment could lead to the activation of protein phosphatase 2A-C (PP2A-C), decrease of anti-apoptotic Bcl-2 family-protein expression including p-Bcl-2 (Ser70), Bcl-2, Bcl-xL, and Mcl-1 as well as the increase of pro-apoptosis Bcl-2 family-protein including Bim, Bad, Bax, and Bak. Furthermore, JS-K caused a marked increase of intracellular NO levels while pre-treatment with Carboxy-PTIO (a NO scavenger) reduced the cytotoxicity effects and the apoptosis rate. Meanwhile, pre-treatment with Carboxy-PTIO attenuated the JS-K-induced up-regulation of PP2A, Cyt c, and cleaved-caspase-9/3 activation. The silencing PP2A-C by siRNA could abolish the activation of PP2A-C, down-regulation of anti-apoptotic Bcl-2 family-protein (p-Bcl-2, Bcl-2, Bcl-xL, and Mcl-1), increase of pro-apoptosis Bcl-2 family-protein (Bim, Bad, Bax, and Bak) and apoptotic-related protein (Cyt c, cleaved caspase-9/3) that were caused by JS-K in HepG2 cells. In addition, pre-treatment with OA (a PP2A inhibitor) also attenuated the above effects induced by JS-K. In summary, NO release from JS-K induces apoptosis through PP2A activation, which contributed to the regulation of Bcl-2 family proteins.

The regulation of lymphocyte activation and proliferation

Activation induced proliferation and clonal expansion of antigen specific lymphocytes is a hallmark of the adaptive immune response to pathogens. Recent studies identify two distinct control phases. In the first T and B lymphocytes integrate antigen and additional costimuli to motivate a programmed proliferative burst that ceases with a return to cell quiescence and eventual death. This proliferative burst is autonomously timed, ensuring an appropriate response magnitude whilst preventing uncontrolled expansion. This initial response is subject to further modification and extension by a range of signals that modify, expand and direct the emergence of a rich array of new cell types. Thus, both robust clonal expansion of a small number of antigen specific T cells, and the concurrent emergence of extensive cellular diversity, confers immunity to a vast array of different pathogens. The in vivo response to a given pathogen is made up by the sum of all responding clones and is reproducible and pathogen specific. Thus, a precise description of the regulatory principles governing lymphocyte proliferation, differentiation and survival is essential to a unified understanding of the immune system.