Plexin domain-containing 1 may be a biomarker of poor prognosis in hepatocellular carcinoma patients,may mediate immune evasion

BACKGROUND For the first time,we investigated the oncological role of plexin domain-containing 1(PLXDC1),also known as tumor endothelial marker 7(TEM7),in hepatocellular carcinoma(HCC).AIM To investigate the oncological profile of PLXDC1 in HCC.METHODS Based on The Cancer Genome Atlas database,we analyzed the expression of PLXDC1 in HCC.Using immunohistochemistry,quantitative real-time polymerase chain reaction(qRT-PCR),and Western blotting,we validated our results.The prognostic value of PLXDC1 in HCC was analyzed by assessing its correlation with clinicopathological features,such as patient survival,methylation level,tumor immune microenvironment features,and immune cell surface checkpoint expression.Finally,to assess the immune evasion potential of PLXDC1 in HCC,we used the tumor immune dysfunction and exclusion(TIDE)website and immunohistochemical staining assays.RESULTS Based on immunohistochemistry,qRT-PCR,and Western blot assays,overexpression of PLXDC1 in HCC was associated with poor prognosis.Univariate and multivariate Cox analyses indicated that PLXDC1 might be an independent prognostic factor.In HCC patients with high methylation levels,the prognosis was worse than in patients with low methylation levels.Pathway enrichment analysis of HCC tissues indicated that genes upregulated in the high-PLXDC1 subgroup were enriched in mesenchymal and immune activation signaling,and TIDE assessment showed that the risk of immune evasion was significantly higher in the high-PLXDC1 subgroup compared to the low-PLXDC1 subgroup.The high-risk group had a significantly lower immune evasion rate as well as a poor prognosis,and PLXDC1-related risk scores were also associated with a poor prognosis.CONCLUSION As a result of this study analyzing PLXDC1 from multiple biological perspectives,it was revealed that it is a biomarker of poor prognosis for HCC patients,and that it plays a role in determining immune evasion status.

Accurate Diagnosis of SARS-CoV-2 JN.1 by Sanger Sequencing of Receptor-Binding Domain Is Needed for Clinical Evaluation of Its Immune Evasion

Background: Omicron JN.1 has become the dominant SARS-CoV-2 variant in recent months. JN.1 has the highest number of amino acid mutations in its receptor binding domain (RBD) and has acquired a hallmark L455S mutation. The immune evasion capability of JN.1 is a subject of scientific investigation. The US CDC used SGTF of TaqPath COVID-19 Combo Kit RT-qPCR as proxy indicator of JN.1 infections for evaluation of the effectiveness of updated monovalent XBB.1.5 COVID-19 vaccines against JN.1 and recommended that all persons aged ≥ 6 months should receive an updated COVID-19 vaccine dose. Objective: Recommend Sanger sequencing instead of proxy indicator to diagnose JN.1 infections to generate the data based on which guidelines are made to direct vaccination policies. Methods: The RNA in nasopharyngeal swab specimens from patients with clinical respiratory infection was subjected to nested RT-PCR, targeting a 398-base segment of the N-gene and a 445-base segment of the RBD of SARS-CoV-2 for amplification. The nested PCR amplicons were sequenced. The DNA sequences were analyzed for amino acid mutations. Results: The N-gene sequence showed R203K, G204R and Q229K, the 3 mutations associated with Omicron BA.2.86 (+JN.1). The RBD sequence showed 24 of the 26 known amino acid mutations, including the hallmark L455S mutation for JN.1 and the V483del for BA.2.86 lineage. Conclusions: Sanger sequencing of a 445-base segment of the SARS-CoV-2 RBD is useful for accurate determination of emerging variants. The CDC may consider using Sanger sequencing of the RBD to diagnose JN.1 infections for statistical analysis in making vaccination policies.

Immune evasion and therapeutic opportunities based on natural killer cells

Natural killer(NK)cells can elicit an immune response against malignantly transformed cells without recognizing antigens,and they also exhibit cytotoxic effects and immune surveillance functions in tumor immunotherapy.Although several studies have shown the promising antitumor effects of NK cells in immunotherapy,their function is often limited in the tumor microenvironment because tumor cells can easily escape NK cell-induced death.Thus,for efficient tumor immunotherapy,the mechanism by which tumor cells escape NK cell-induced cytotoxicity must be fully understood.Various novel molecules and checkpoint receptors that mediate the disruption of NK cells in the tumor microenvironment have been discovered.In this review,we analyze and detail the major activating and inhibitory receptors on the surface of NK cells to delineate the mechanism by which tumor cells suppress NKG2D ligand expression and increase tumor receptor and inhibitory receptor expression[NKG2A,programmed cell death1(PD-1),and T-cell immunoglobulin and immunoreceptor tyrosine inhibitory motif(TIGIT)]on the NK cell surface,and thus inhibit NK cell activity.We also reviewed the current status of treatments based on these surface molecules.By comparing the therapeutic effects related to the treatment status and bypass mechanisms,we attempt to identify optimal single or combined treatments to suggest new treatment strategies for tumor immunotherapy.

Optimal maneuvering strategy of spacecraft evasion based on angles-only measurement and observability analysis

Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous. To deal with this problem, an optimal maneuvering strategy based on the relative navigation observability degree is proposed with angles-only measurements. A maneuver evasion relative navigation model in the spacecraft’s orbital plane is constructed and the observability measurement criteria with process noise and measurement noise are defined based on the posterior Cramer-Rao lower bound. Further, the optimal maneuver evasion strategy in spacecraft’s orbital plane based on the observability is proposed. The strategy provides a new idea for spacecraft to evade safety threats autonomously. Compared with the spacecraft evasion problem based on the absolute navigation, more accurate evasion results can be obtained. The simulation indicates that this optimal strategy can weaken the system’s observability and reduce the state estimation accuracy of the non-cooperative target, making it impossible for the non-cooperative target to accurately approach the spacecraft.

Research Hotspot and Application Status of Immune Evasion Mechanism in Ovarian Cancer

Ovarian cancer is one of the three major malignant tumors in gynecology, with increasing incidence and mortality rates. Currently, the main treatment methods remain surgical intervention in combination with chemotherapy. However, due to its high recurrence rate and the risk of drug resistance, the overall prognosis is poor. Ovarian cancer has been identified as an immunegenic tumor, and in recent years, with the continued advancement of research into immune evasion mechanisms, immunotherapy has emerged as a groundbreaking treatment modality. This article will focus on the immune escape mechanisms and their application in ovarian cancer, providing a comprehensive overview of its current status and the challenges it faces.

Role of apoptosis resistance in immune evasion and metastasis of colorectal cancer

The host immune system functions as a guardian against tumor development. It has been demonstrated that cytotoxic T lymphocyte (CTL)-mediated cytotoxic pathways function to inhibit or delay human colorectal cancer development. However, the host anti-tumor immune responses also 'edit' the tumor and select for more aggressive variants, resulting in immune evasion and tumor escape. Fas is a death receptor that mediates one of the major cytotoxic effector mechanisms of the CTLs. Fas is highly expressed in normal human colon epithelial cells but is frequently silenced in colorectal carcinoma, especially in metastatic colorectal carcinoma, suggesting that loss of Fas expression and function may be an immune evasion and tumor escape mechanism. In addition, recent studies indicated that Fas also mediates cellular proliferation signaling pathways to promote tumor development. Therefore, the death receptor Fas may not only transduce death signals to suppress tumor development but also activate cellular proliferation and the migration process to promote tumor growth and progression. Thus, understanding the mechanisms by which the Fas receptor and its associated protein complex transduces the death and survival signals may identify molecular targets for the development of therapeutic strategy to enhance the Fas-mediated death signals to increase the efficacy of cancer immunotherapy.

Immune evasion mechanisms and therapeutic strategies in gastric cancer

Gastric cancer(GC)is a malignancy with a high incidence and mortality.The tumor immune microenvironment plays an important role in promoting cancer development and supports GC progression.Accumulating evidence shows that GC cells can exert versatile mechanisms to remodel the tumor immune microenvironment and induce immune evasion.In this review,we systematically summarize the intricate crosstalk between GC cells and immune cells,including tumor-associated macrophages,neutrophils,myeloid-derived suppressor cells,natural killer cells,effector T cells,regulatory T cells,and B cells.We focus on how GC cells alter these immune cells to create an immunosuppressive microenvironment that protects GC cells from immune attack.We conclude by compiling the latest progression of immune checkpoint inhibitor-based immunotherapies,both alone and in combination with conventional therapies.Anti-cytotoxic Tlymphocyte-associated protein 4 and anti-programmed cell death protein 1/programmed death-ligand 1 therapy alone does not provide substantial clinical benefit for GC treatment.However,the combination of immune checkpoint inhibitors with chemotherapy or targeted therapy has promising survival advantages in refractory and advanced GC patients.This review provides a comprehensive understanding of the immune evasion mechanisms of GC,and highlights promising immunotherapeutic strategies.

EXPRESSION OF FLIP IN HUMAN COLON CARCINOMAS: A NEW MECHANISM OF IMMUNE EVASION

Objective： It has been proposed that Fas ligand （FasL） may play an important role in immune escape of tumors and FLIP is an important mediator of Fas/FasL pathway. In this study, the expression of FLIP was determined in human colon carcinoma cell lines and tissue to investigate the new mechanism of immune evasion of human colon carcinomas. Methods： RT-PCR and immunohistochemistry （IHC） were performed to investigate the expression of FLIP in human colon carcinoma cell lines SW480, LS174 and twenty human primary colon carcinoma specimens. Results： It was shown that SW480 cells, LS174 cells and primary colon carcinoma specimen constitutively expressed FLIP at the mRNA and protein level. The expression of FLIP was not found in the epithelial cells of normal colon mucosa. Conclusion： FLIP was expressed in human primary colon carcinoma specimens but not in the normal counterpart. It suggested that the expression of FLIP may occur during the malignant transformation from normal colon epithelial cells to colon carcinoma cells. Tumor cells might obtain the ability to resist the Fas-mediated apoptosis by expressing FLIP. The expression of FLIP might contribute to the formation of colon carcinomas.

Targeting pancreatic cancer immune evasion by inhibiting histone deacetylases

The immune system plays a vital role in maintaining the delicate balance between immune recognition and tumor development.Regardless,it is not uncommon that cancerous cells can intelligently acquire abilities to bypass the antitumor immune responses,thus allowing continuous tumor growth and development.Immune evasion has emerged as a significant factor contributing to the progression and immune resistance of pancreatic cancer.Compared with other cancers,pancreatic cancer has a tumor microenvironment that can resist most treatment modalities,including emerging immunotherapy.Sadly,the use of immunotherapy has yet to bring significant clinical breakthrough among pancreatic cancer patients,suggesting that pancreatic cancer has successfully evaded immunomodulation.In this review,we summarize the impact of genetic alteration and epigenetic modification(especially histone deacetylases,HDAC)on immune evasion in pancreatic cancer.HDAC overexpression significantly suppresses tumor suppressor genes,contributing to tumor growth and progression.We review the evidence on HDAC inhibitors in tumor eradication,improving T cells activation,restoring tumor immunogenicity,and modulating programmed death 1 interaction.We provide our perspective in targeting HDAC as a strategy to reverse immune evasion in pancreatic cancer.

Immune evasion by Plasmodium falciparum parasites: converting a host protection mechanism for the parasite′s benefit

Immune evasion is a strategy used by pathogenic microbes to evade the host immune system in order to ensure successful propagation. Immune evasion is particularly important for the blood stages of Plasmodium falciparum, the causative agent of the deadly disease malaria tropica. Because Plasmodium blood stage parasites require human erythrocytes for replication, their ability to evade attack by the human immune system is essential for parasite survival. In order to escape immunity-induced killing, the intraerythrocytic parasites have evolved a variety of evasion mechanisms, including expansion of plasmodial surface proteins, organ-specific sequestration of the infected red blood cells and acquisition of immune-regulatory proteins by the parasite. This review aims to highlight recent advances in the molecular understanding of the immune evasion strategies by P. falciparum, including antigenic variation, surface protein polymorphisms and invasion ligand diversification. The review will further discuss new findings on the regulatory mechanisms applied by P. falciparum to avoid lysis by the human complement as well as killing by immune factors of the mosquito vector.

Explicitness Evasion with Humor under Cooperative Principle

Explicitness evasion in communication is like lube that avoids hurting the other party's feeling. It lubricates human relationship in communication and helps to save face of communicators. Too much conversational explicitness is easy to give rise to misunderstandings even if it is for good intentions. And when the divergence among two parties become exacerbated, the conflict or even fighting will arise as a result. So to create a light-hearted conversational atmosphere, explicitness evasion, an aesthetic speech art, is deeply thought-provoking. Therefore, this study attempts to touch on the validity of applying humor under Cooperative Principle to the explicitness evasion. Hopefully, readers can better understand how to avoid hurting others inadvertently when speaking and how to achieve successful conversations. Moreover, it can help practitioners to find some sound methods to combine speech and humanity together to make them harmonious in the long run.

A novel evasion guidance for hypersonic morphing vehicle via intelligent maneuver strategy

This paper presents a novel evasion guidance law for hypersonic morphing vehicles,focusing on determining the optimized wing's unfolded angle to promote maneuverability based on an intelligent algorithm.First,the pursuit-evasion problem is modeled as a Markov decision process.And the agent's action consists of maneuver overload and the unfolded angle of wings,which is different from the conventional evasion guidance designed for fixed-shape vehicles.The reward function is formulated to ensure that the miss distances satisfy the prescribed bounds while minimizing energy consumption.Then,to maximize the expected cumulative reward,a residual learning method is proposed based on proximal policy optimization,which integrates the optimal evasion for linear cases as the baseline and trains to optimize the performance for nonlinear engagement with multiple pursuers.Therefore,offline training guarantees improvement of the constructed evasion guidance law over conventional ones.Ultimately,the guidance law for online implementation includes only analytical calculations.It maps from the confrontation state to the expected angle of attack and the unfolded angle while retaining high computational efficiency.Simulations show that the proposed evasion guidance law can utilize the change of unfolded angle to extend the maximum overload capability.And it surpasses conventional maneuver strategies by ensuring better evasion efficacy and higher energy efficiency.

Unsynchronized butyrophilin molecules dictate cancer cell evasion of Vγ9Vδ2 T-cell killing

Vγ9Vδ2 T cells are specialized effector cells that have gained prominence as immunotherapy agents due to their ability to target and kill cells with altered pyrophosphate metabolites.In our effort to understand how cancer cells evade the cell-killing activity of Vγ9Vδ2 T cells,we performed a comprehensive genome-scale CRISPR screening of cancer cells.We found that four molecules belonging to the butyrophilin(BTN)family,specifically BTN2A1,BTN3A1,BTN3A2,and BTN3A3,are critically important and play unique,nonoverlapping roles in facilitating the destruction of cancer cells by primary Vγ9Vδ2 T cells.The coordinated function of these BTN molecules was driven by synchronized gene expression,which was regulated by IFN-γsignaling and the RFX complex.Additionally,an enzyme called QPCTL was shown to play a key role in modifying the N-terminal glutamine of these BTN proteins and was found to be a crucial factor in Vγ9Vδ2 T cell killing of cancer cells.Through our research,we offer a detailed overview of the functional genomic mechanisms that underlie how cancer cells escape Vγ9Vδ2 T cells.Moreover,our findings shed light on the importance of the harmonized expression and function of gene family members in modulating T-cell activity.

Elevated nuclear PIGL disrupts the cMyc/BRD4 axis and improves PD-1 blockade therapy by dampening tumor immune evasion

To improve the efficacy of lenvatinib in combination with programmed death-1(PD-1)blockade therapy for hepatocellular carcinoma(HCC),we screened the suppressive metabolic enzymes that sensitize HCC to lenvatinib and PD-1 blockade,thus impeding HCC progression.After analysis of the CRISPR‒Cas9 screen,phosphatidylinositol-glycan biosynthesis class L(PIGL)ranked first in the positive selection list.PIGL depletion had no effect on tumor cell growth in vitro but reprogrammed the tumor microenvironment(TME)in vivo to support tumor cell survival.Specifically,nuclear PIGL disrupted the interaction between cMyc/BRD4 on the distant promoter of target genes and thus decreased the expression of CCL2 and CCL20,which are involved in shaping the immunosuppressive TME by recruiting macrophages and regulatory T cells.PIGL phosphorylation at Y81 by FGFR2 abolished the interaction of PIGL with importinα/β1,thus retaining PIGL in the cytosol and facilitating tumor evasion by releasing CCL2 and CCL20.Clinically,elevated nuclear PIGL predicts a better prognosis for HCC patients and presents a positive correlation with CD8+T-cell enrichment in tumors.Clinically,our findings highlight that the nuclear PIGL intensity or the change in PIGL-Y81 phosphorylation should be used as a biomarker to guide lenvatinib with PD-1 blockade therapy.

Unveiling T cell evasion mechanisms to immune checkpoint inhibitors in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous and aggressive hematologic malignancy that is associated with a high relapse rate and poor prognosis. Despite advances in immunotherapies in solid tumors and other hematologic malignancies, AML has been particularly difficult to treat with immunotherapies, as their efficacy is limited by the ability of leukemic cells to evade T cell recognition. In this review, we discuss the common mechanisms of T cell evasion in AML: (1) increased expression of immune checkpoint molecules;(2) downregulation of antigen presentation molecules;(3) induction of T cell exhaustion;and (4) creation of an immunosuppressive environment through the increased frequency of regulatory T cells. We also review the clinical investigation of immune checkpoint inhibitors (ICIs) in AML. We discuss the limitations of ICIs, particularly in the context of T cell evasion mechanisms in AML, and we describe emerging strategies to overcome T cell evasion, including combination therapies. Finally, we provide an outlook on the future directions of immunotherapy research in AML, highlighting the need for a more comprehensive understanding of the complex interplay between AML cells and the immune system.

An Empirical Study on the Effectiveness of Adversarial Examples in Malware Detection

Antivirus vendors and the research community employ Machine Learning(ML)or Deep Learning(DL)-based static analysis techniques for efficient identification of new threats,given the continual emergence of novel malware variants.On the other hand,numerous researchers have reported that Adversarial Examples(AEs),generated by manipulating previously detected malware,can successfully evade ML/DL-based classifiers.Commercial antivirus systems,in particular,have been identified as vulnerable to such AEs.This paper firstly focuses on conducting black-box attacks to circumvent ML/DL-based malware classifiers.Our attack method utilizes seven different perturbations,including Overlay Append,Section Append,and Break Checksum,capitalizing on the ambiguities present in the PE format,as previously employed in evasion attack research.By directly applying the perturbation techniques to PE binaries,our attack method eliminates the need to grapple with the problem-feature space dilemma,a persistent challenge in many evasion attack studies.Being a black-box attack,our method can generate AEs that successfully evade both DL-based and ML-based classifiers.Also,AEs generated by the attack method retain their executability and malicious behavior,eliminating the need for functionality verification.Through thorogh evaluations,we confirmed that the attack method achieves an evasion rate of 65.6%against well-known ML-based malware detectors and can reach a remarkable 99%evasion rate against well-known DL-based malware detectors.Furthermore,our AEs demonstrated the capability to bypass detection by 17%of vendors out of the 64 on VirusTotal(VT).In addition,we propose a defensive approach that utilizes Trend Locality Sensitive Hashing(TLSH)to construct a similarity-based defense model.Through several experiments on the approach,we verified that our defense model can effectively counter AEs generated by the perturbation techniques.In conclusion,our defense model alleviates the limitation of the most promising defense method,adversarial training,which is only effective against the AEs that are included in the training classifiers.

Opportunities and challenges of CD47-targeted therapy in cancer immunotherapy

Cancer immunotherapy has emerged as a promising strategy for the treatment of cancer,with the tumor microenvironment(TME)playing a pivotal role in modulating the immune response.CD47,a cell surface protein,has been identified as a crucial regulator of the TME and a potential therapeutic target for cancer therapy.However,the precise functions and implications of CD47 in the TME during immunotherapy for cancer patients remain incompletely understood.This comprehensive review aims to provide an overview of CD47’s multifaced role in TME regulation and immune evasion,elucidating its impact on various types of immunotherapy outcomes,including checkpoint inhibitors and CAR T-cell therapy.Notably,CD47-targeted therapies offer a promising avenue for improving cancer treatment outcomes,especially when combined with other immunotherapeutic approaches.The review also discusses current and potential CD47-targeted therapies being explored for cancer treatment and delves into the associated challenges and opportunities inherent in targeting CD47.Despite the demonstrated effectiveness of CD47-targeted therapies,there are potential problems,including unintended effects on healthy cells,hematological toxicities,and the development if resistance.Consequently,further research efforts are warranted to fully understand the underlying mechanisms of resistance and to optimize CD47-targeted therapies through innovative combination approaches,ultimately improving cancer treatment outcomes.Overall,this comprehensive review highlights the significance of CD47 as a promising target for cancer immunotherapy and provides valuable insight into the challenges and opportunities in developing effective CD47-targeted therapies for cancer treatment.

Innate immunity in tuberculosis: host defense vs pathogen evasion

The major innate immune cell types involved in tuberculosis(TB)infection are macrophages,dendritic cells(DCs),neutrophils and natural killer(NK)cells.These immune cells recognize the TB-causing pathogen Mycobacterium tuberculosis(Mtb)through various pattern recognition receptors(PRRs),including but not limited to Toll-like receptors(TLRs),Nod-like receptors(NLRs)and C-type lectin receptors(CLRs).Upon infection by Mtb,the host orchestrates multiple signaling cascades via the PRRs to launch a variety of innate immune defense functions such as phagocytosis,autophagy,apoptosis and inflammasome activation.In contrast,Mtb utilizes numerous exquisite strategies to evade or circumvent host innate immunity.Here we discuss recent research on major host innate immune cells,PRR signaling,and the cellular functions involved in Mtb infection,with a specific focus on the host’s innate immune defense and Mtb immune evasion.A better understanding of the molecular mechanisms underlying host–pathogen interactions could provide a rational basis for the development of effective anti-TB therapeutics.

Evasion and pursuit guidance law against defended target

This paper investigates a new approach for a scenario in which an Attacker attempts to intercept a defended aerial Target. The problem is formulated as a game among three players, an Attacker, a Defender, and a Target, with bounded controls. In the considered pursuit–evasion problem, the Target uses an optimal evasion strategy and the Defender uses an optimal pursuit strategy.The proposed approach focuses on the miss distance as the outcome of the conflict. The infeasible region for the initial Zero-Effort-Miss（ZEM） distance between the Attacker and the Defender, for a scenario in which the Attacker evades the Defender, is analyzed, assuming that the Attacker uses a control effort chosen from the permitted control region. The sufficient conditions are investigated under which, for ideal players, the Attacker can pursue the Target while evading the Defender launched by the Target. The guidance provided on how the Attacker can accomplish the task is divided into two parts. During the final time between the Attacker and the Defender, the Attacker chooses the control effort that guarantees the miss distance, and then uses the optimal pursuit strategy to accomplish the task. The derived guidance law is verified by nonlinear simulation.