Adaptive Immune Resistance: How Cancer Protects from Immune Attack

Radiation-targeted immunotherapy: A new perspective in cancer radiotherapy

In contemporary oncology, radiation therapy and immunotherapy stand as critical treatments, each with distinct mechanisms and outcomes. Radiation therapy, a key player in cancer management, targets cancer cells by damaging their DNA with ionizing radiation. Its effectiveness is heightened when used alongside other treatments like surgery and chemotherapy. Employing varied radiation types like X-rays, gamma rays, and proton beams, this approach aims to minimize damage to healthy tissue. However, it is not without risks, including potential damage to surrounding normal cells and side effects ranging from skin inflammation to serious long-term complications. Conversely, immunotherapy marks a revolutionary step in cancer treatment, leveraging the body's immune system to target and destroy cancer cells. It manipulates the immune system's specificity and memory, offering a versatile approach either alone or in combination with other treatments. Immunotherapy is known for its targeted action, long-lasting responses, and fewer side effects compared to traditional therapies. The interaction between radiation therapy and immunotherapy is intricate, with potential for both synergistic and antagonistic effects. Their combined use can be more effective than either treatment alone, but careful consideration of timing and sequence is essential. This review explores the impact of various radiation therapy regimens on immunotherapy, focusing on changes in the immune microenvironment, immune protein expression, and epigenetic factors, emphasizing the need for personalized treatment strategies and ongoing research to enhance the efficacy of these combined therapies in cancer care.

Microneedle-Mediated Cell Therapy

Microneedles have emerged as a promising platform for transdermal drug delivery with prominent advantages, such as enhanced permeability, mitigated pain, and improved patient adherence. While microneedles have primarily been employed for delivering small molecules, nucleic acids, peptides, and proteins, recent researches have demonstrated their prospect in combination with cell therapy. Cell therapy involving administration or transplantation of living cells (e.g. T cells, stem cells, and pancreatic cells) has gained significant attention in preclinical and clinical applications for various disease treatments. However, the effectiveness of systemic cell delivery may be restricted in localized conditions like solid tumors and skin disorders due to limited penetration and accumulation into the lesions. In this perspective, an overview of recent advances in microneedle-assisted cell delivery for immunotherapy, tissue regeneration, and hormone modulation, with respect to their mechanical property, cell loading capacity, as well as viability and bioactivity of the loaded cells is provided. Potential challenges and future perspectives with microneedle-mediated cell therapy are also discussed.

The role of intestinal flora on tumor immunotherapy: recent progress and treatment implications

Immunotherapy, specifically immune checkpoint inhibitors, has emerged as a promising approach for treating malignant tumors. The gut, housing approximately 70 % of the body's immune cells, is abundantly populated with gut bacteria that actively interact with the host's immune system. Different bacterial species within the intestinal flora are in a delicate equilibrium and mutually regulate each other. However, when this balance is disrupted, pathogenic microorganisms can dominate, adversely affecting the host's metabolism and immunity, ultimately promoting the development of disease. Emerging researches highlight the potential of interventions such as fecal microflora transplantation (FMT) to improve antitumor immune response and reduce the toxicity of immunotherapy. These remarkable findings suggest the major role of intestinal flora in the development of cancer immunotherapy and led us to the hypothesis that intestinal flora transplantation may be a new breakthrough in modifying immunotherapy side effects.

Sequential immunotherapy and targeted therapy for metastatic BRAF V600 mutated melanoma: 4-year survival and biomarkers evaluation from the phase II SECOMBIT trial

No prospective data were available prior to 2021 to inform selection between combination BRAF and MEK inhibition versus dual blockade of programmed cell death protein-1 (PD-1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) as first-line treatment options for BRAFV600-mutant melanoma. SECOMBIT (NCT02631447) was a randomized, three-arm, noncomparative phase II trial in which patients were randomized to one of two sequences with immunotherapy or targeted therapy first, with a third arm in which an 8-week induction course of targeted therapy followed by a planned switch to immunotherapy was the first treatment. BRAF/MEK inhibitors were encorafenib plus binimetinib and checkpoint inhibitors ipilimumab plus nivolumab. Primary outcome of overall survival was previously reported, demonstrating improved survival with immunotherapy administered until progression and followed by BRAF/MEK inhibition. Here we report 4-year survival outcomes, confirming long-term benefit with first-line immunotherapy. We also describe preliminary results of predefined biomarkers analyses that identify a trend toward improved 4-year overall survival and total progression-free survival in patients with loss-of-function mutations affecting JAK or low baseline levels of serum interferon gamma (IFNy). These long-term survival outcomes confirm immunotherapy as the preferred first-line treatment approach for most patients with BRAFV600-mutant metastatic melanoma, and the biomarker analyses are hypothesis-generating for future investigations of predictors of durable benefit with dual checkpoint blockade and targeted therapy.

Activation of Stimulator of Interferon Genes (STING): Promising Strategy to Overcome Immune Resistance in Prostate Cancer

Prostate cancer (PCa) is the most frequent and second-lethal cancer among men. Despite considerable efforts to explore treatments like autologous cellular immunotherapy and immune checkpoint inhibitors, their success remains limited. The intricate tumor microenvironment (TME) and its interaction with the immune system pose significant challenges in PCa treatment. Consequently, researchers have directed their focus on augmenting the immune system's anti-tumor response by targeting the STimulator of the Interferon Genes (STING) pathway. The STING pathway is activated when foreign DNA is detected in the cytoplasm of innate immune cells, resulting in the activation of endoplasmic reticulum (ER) STING. This, in turn, triggers an augmentation of signaling, leading to the production of type I interferon (IFN) and other pro-inflammatory cytokines. Numerous studies have demonstrated that activation of the STING pathway induces immune system rejection and targeted elimination of PCa cells. Researchers have been exploring various methods to activate the STING pathway, including the use of bacterial vectors to deliver STING agonists and the combination of radiation therapy with STING agonists. Achieving effective radiation therapy with minimal side effects and optimal anti-tumor immune responses necessitates precise adjustments to radiation dosing and fractionation schedules. This comprehensive review discusses promising findings from studies focusing on activating the STING pathway to combat PCa. The STING pathway exhibits the potential to serve as an effective treatment modality for PCa, offering new hope for improving the lives of those affected by this devastating disease.

Using immunogenic cell death to improve anticancer efficacy of immune checkpoint inhibitors: From basic science to clinical application

Even though the discovery of immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment, a high proportion of patients do not respond. Moreover, some types of cancers are refractory to these treatments. Thus, the need to find predictive biomarkers of efficacy and to evaluate the association with other treatments, such as chemotherapy or radiotherapy, appears to be essential. Because ICIs reactivate or maintain an active status of T cells, one possibility is to combine these treatments with therapies that engage an immune response against tumor cells. Thus, by inducing immunogenic cell death (ICD) of cancer cells, some conventional anticancer treatments induce such immune response and may have an interest to be combined with ICIs. In this review, we explore preclinical studies and clinical trials that evaluate the combination of ICIs with ICD inducers. More than inducing ICD, some of these treatments appear to modulate the tumor microenvironment and more particularly to inhibit immunosuppression, thus improving treatment efficacy.

Stem Cells and Tumor-Killing Virus to Target Brain Tumor: In Pursuit to Bring a Potential Delivery Vehicle for the Central Nervous System Tumors

To target brain cancer, various therapeutic options are present to fight against cancer cells. But the existing therapies are not showing a proper curation of cancer patients. Henceforth, activating the immune cells and targeting oncogenes/proteins might be an emerging therapeutic approach to target and destroy malignant brain tumor. Stem cells (SCs) are considered potential immunomodulators that trigger the highly suppressed immune system in the tumor microenvironment. Also, engineered SCs can repress the aberrantly expressed oncoproteins that cause tumor cell proliferation and growth. SCs have an excellent migration capability to reach the infected site and support the regeneration of damaged blood vessels and tissues. Likewise, oncolytic virotherapy (OVT) is a promising novel therapeutic molecule in which genetically modified viruses can selectively replicate and destroy cancer cells without harming healthy cells. Same as SCs, oncolytic viruses (OVs) tend to stimulate the host's innate and adaptive immune response to battle against the advanced brain tumor. In clinical studies, various OVs have shown good immunogenic responses with a high safety profile and tolerability against cancer patients with reduced morbidity and mortality rate. SCs act as an attractive cargo for OVs which helps to influence the tumor site and destroy the tumor volume. SCs protect the OVs from systemic degradation and promote therapeutic efficacy against cancer cells. SCs carried OVs might be a potential therapeutic way to bring an effective treatment option for brain tumors.

TREM1 is involved in the mechanism between asthma and lung cancer by regulating the Toll‑like receptor signaling pathway

Lung cancer and asthma are both global health problems with significant economic consequences. Recent studies have demonstrated that asthma may be a risk factor for lung cancer. The present study aimed to explore the pathogenesis between these two diseases through a comprehensive analysis. Differentially expressed genes (DEGs) screened in the asthma-related GSE165934 dataset were analyzed to find relevant inflammatory pathways. Overlapping genes regulated by inflammatory pathways and lung cancer-DEGs from The Cancer Genome Atlas (TCGA) were obtained and subjected to survival and gene-wide mutation analyses, and nomogram construction to determine the hub gene. The hub gene was further analyzed through expression validation, immunoassays and functional experiments to investigate its role and mechanism in lung cancer. Functional enrichment analysis showed that 1,275 DEGs from GSE165934 were closely associated with the Toll-like receptor signaling pathway, and 8 overlapping genes were identified from 12 genes regulated by the Toll-like receptor signaling pathway and 3,134 TCGA-DEGs. After a series of bioinformatics analyses, it was found that triggering receptor expressed on myeloid cells 1 (TREM1) was the hub gene involved in the mechanism of asthma and lung cancer. TREM1 was also found to be a suppressor gene in lung cancer correlated with immune cells, immune checkpoint-related genes and tumor mutational burden score. Additionally, the results of Cell Counting Kit-8 and Transwell experiments demonstrated that overexpression of TREM1 could significantly inhibit the invasion, proliferation and migration of lung cancer cells. Reverse transcription-quantitative PCR and western blotting demonstrated that the overexpression of TREM1 could also significantly reduce the level of Toll-like receptor signaling pathway proteins. The present findings suggest that TREM1 is associated with the mechanism of asthma and lung cancer through its regulation of the Toll-like receptor signaling pathway. Furthermore, TREM1 may serve as a potential treatment target and prognostic indicator for patients with lung cancer.

The role of intestinal flora on tumorigenesis, progression, and the efficacy of PD-1/PD-L1 antibodies in colorectal cancer

Intestinal flora affects the maturation of the host immune system, serves as a biomarker and efficacy predictor in the immunotherapy of several cancers, and has an important role in the development of colorectal cancer (CRC). Anti-PD-1/PD-L1 antibodies have shown satisfactory results in MSI-H/dMMR CRC but performed poorly in patients with MSS/pMMR CRC. In recent years an increasing number of studies have shown that intestinal flora has an important impact on anti-PD-1/PD-L1 antibody efficacy in CRC patients. Preclinical and clinical evidence have suggested that anti-PD-1/PD-L1 antibody efficacy can be improved by altering the composition of the intestinal flora in CRC. Herein, we summarize the studies related to the influence of intestinal flora on anti-PD-1/PD-L1 antibody efficacy in CRC and discuss the potential underlying mechanism(s). We have focused on the impact of the intestinal flora on the efficacy and safety of anti-PD-1/PD-L1 antibodies in CRC and how to better utilize the intestinal flora as an adjuvant to improve the efficacy of anti-PD-1/PD-L1 antibodies. In addition, we have provided a basis for the potential of the intestinal flora as a new treatment modality and indicator for determining patient prognosis.

Discovery of Anti-CD47 Peptides as Innate Immune Checkpoint Inhibitors

Cancer immunotherapy targeting adaptive immune cells has been attracting considerable interest due to its great success in treating multiple cancers. Recently, there is also increasing interest in agents that can stimulate innate immune cell activities. Immune checkpoint inhibitors targeting innate immune cells can block inhibitory interactions ('don't eat me' signals) between tumor cells and phagocytes. CD47 is a transmembrane protein overexpressed in various cancers and acts as a potent 'do not eat me' signal that contributes to the immune evasion of cancer cells. Anti-CD47 peptides that can bind to CD47 and block CD47/SIRPα interaction were discovered using a novel phage display biopanning strategy. Anti-CD47 peptides enhanced the macrophage-mediated phagocytosis of NCI-H82 tumor cells in vitro. Unlike anti-CD47 antibodies, these peptides do not induce the agglutination of RBCs. Moreover, anti-CD47 peptides exhibit high specificity for MC-38 cancer cells expressing CD47. CMP-22 peptide showed the ability to increase the antitumor activity of doxorubicin and extends the survival of CT26 tumor-bearing mice. The discovered anti-CD47 peptides can be considered potential candidates for cancer immunotherapy by blocking the CD47/SIRPα interaction, especially in combination with chemotherapy, to elicit synergistic effects.

The progress of research on immune checkpoint inhibitor resistance and reversal strategies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in humans, which is prone to recurrence and metastasis and has a poor prognosis. The occurrence and progression of HCC are closely related to immune elimination, immune homeostasis, and immune escape of the immune system. In recent years, immunotherapy, represented by immune checkpoint inhibitors (ICIs), has shown powerful anti-tumor capabilities in HCC patients. However, there are still some HCC patients who cannot benefit from ICIs treatment due to their innate or acquired drug resistance. Therefore, it is of great practical significance to explore the possible mechanisms of resistance to ICIs in HCC and to use them as a target to design strategies to reverse resistance, to overcome drug resistance in HCC and to improve the prognosis of patients. This article summarizes the possible primary (tumor microenvironment alteration, and signaling pathways, etc.) and acquired (immune checkpoint upregulation) resistance mechanisms in patients with HCC treated with ICIs, and based on this, discusses the status and effectiveness of combination drug strategy to reverse drug resistance, to provide a reference for subsequent related studies and decisions.

Endothelial-to-mesenchymal transition in tumour progression and its potential roles in tumour therapy

Tumour-associated endothelial cells (TECs) are a critical stromal cell type in the tumour microenvironment and play central roles in tumour angiogenesis. Notably, TECs have phenotypic plasticity, as they have the potential to transdifferentiate into cells with a mesenchymal phenotype through a process termed endothelial-to-mesenchymal transition (EndoMT). Many studies have reported that EndoMT influences multiple malignant biological properties of tumours, such as abnormal angiogenesis and tumour metabolism, growth, metastasis and therapeutic resistance. Thus, the value of targeting EndoMT in tumour treatment has received increased attention. In this review, we comprehensively explore the phenomenon of EndoMT in the tumour microenvironment and identify influencing factors and molecular mechanisms responsible for EndoMT induction. Furthermore, the pathological functions of EndoMT in tumour progression and potential therapeutic strategies for targeting EndoMT in tumour treatment are also discussed to highlight the pivotal roles of EndoMT in tumour progression and therapy.

Understanding immune checkpoints and PD-1/PD-L1-mediated immune resistance towards tumour immunotherapy

Immunotherapy has emerged as a transformative approach in the treatment of various cancers, offering new hope for patients previously faced with limited treatment options. A cornerstone of cancer immunotherapy lies in targeting immune checkpoints, particularly the programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1) pathway. Immune checkpoints serve as crucial regulators of the immune response, preventing excessive immune activity and maintaining self-tolerance. PD-1, expressed on the surface of T cells, and its ligand PD-L1, expressed on various cell types, including cancer cells and immune cells, play a central role in this regulatory process. Although the success rate associated with these immunotherapies is very promising, most patients still show intrinsic or acquired resistance. Since the mechanisms related to PD-1/PD-L1 resistance are not well understood, an in-depth analysis is necessary to improve the success rate of anti-PD-1/PD-L1 therapy. Hence, here we provide an overview of PD-1, its ligand PD-L1, and the resistance mechanism towards PD-1/PD-L1. Furthermore, we have discussed the plausible solution to increase efficacy and clinical response. For the following research, joint endeavours of clinicians and basic scientists are essential to address the limitation of resistance towards immunotherapy.

Construction of disulfidptosis-related lncRNA signature for predicting the prognosis and immune escape in colon adenocarcinoma

Colon adenocarcinoma (COAD) is one of the most frequent types of cancer worldwide. Disulfidptosis has been identified as a new mode of cell death recently. The goal of this study was to explore the possibility of a connection between disulfidptosis and COAD. RNA sequencing data from COAD patients were retrieved from the The Cancer Genome Atlas (TCGA) database for this investigation. R software and various methods were used to identify disulfidptosis-related lncRNAs (DRLs) in COAD, and a prognostic model was created based on 6 DRLs (AP003555.1, AL683813.1, SNHG7, ZEB1-AS1, AC074212.1, RPL37A-DT). The prognostic model demonstrated a good accuracy in predicting the prognosis of COAD patients, according to receiver operating characteristic (ROC) curve and Concordance index (C-index) analyses. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed significant differences in biological functions and signaling pathways involved in differential genes in risk subgroups, including protein - DNA complex subunit organization, Hippo signaling pathway, Wnt signaling pathway. TIDE analysis was done on risk groupings in this study, and it found that patients in the high-risk group had more immune escape potential and were less probable to react to immunotherapy. Real-time quantitative pcr (qRT-PCR) was used to identify the relatively high expression of 6 DRLs in colon cancer cell lines. In summary, 6 DRLs were identified as possible novel molecular therapy targets for COAD in this investigation. This prognostic model has the potential to be a novel tool for forecasting COAD prognosis in clinical practice, as well as providing new insights on the potential function and mechanism of disulfidptosis in the COAD process.

Expression Changes in Programmed Death Ligand 1 from Precancerous Lesions to Invasive Adenocarcinoma in Subcentimeter Pulmonary Nodules: A Large Study of 2022 Cases in China

PURPOSE

This large-scale, multicenter, retrospective observational study aimed to evaluate the clinicopathological and molecular profiles associated with programmed death-ligand 1 (PD-L1) expression in precancerous lesions and invasive adenocarcinoma in subcentimeter pulmonary nodules.

PATIENTS AND METHODS

Patients with histologically confirmed atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (ADC) were included. PD-L1 expression was evaluated at each center using a PD-L1 immunohistochemistry 22C3 pharmDx kit (Agilent, Santa Clara, CA, USA). The tumor proportion score (TPS) cutoff values were set at ≥ 1% and ≥ 50%.

RESULTS

A total of 2022 nodules from 1844 patients were analyzed. Of these, 9 (0.45%) nodules had PD-L1 TPS ≥ 50%, 187 (9.25%) had PD-L1 TPS 1-49%, and 1826 (90.30%) had PD-L1 TPS < 1%. A total of 378 (18.69%), 1016 (50.25%), and 628 (31.06%) nodules were diagnosed as AAH/AIS, MIA, and ADC, respectively, by pathology. A total of 1377 (68.10%), 591 (25.67%), and 54 (2.67%) nodules were diagnosed as pure ground-glass opacity (GGO), mixed GGO, and solid nodules, respectively, by computed tomography. There was a significant difference between PD-L1 expression and anaplastic lymphoma kinase (ALK) mutation status (P < 0.001). PD-L1 expression levels were significantly different from those determined using the International Association for the Study of Lung Cancer (IASLC) grading system (P < 0.001).

CONCLUSIONS

PD-L1 expression was significantly associated with radiological and pathological invasiveness and driver mutation status in subcentimeter pulmonary nodules. The significance of PD-L1 expression in the evolution of early-stage lung adenocarcinoma requires further investigation.

Anti-PD-L1 × anti-CD3 bispecific T-cell engager-armed T cells can overcome immunosuppression and redirect T cells to kill breast cancer cells expressing PD-L1

T cell-based immunotherapy has transformed cancer treatment. Nonetheless, T cell antitumor activity can be inhibited by an immune checkpoint molecule expressed on cancer cells, program death ligand 1 (PD-L1), which interacts with the PD-1 on T cells. We generated αPD-L1 × αCD3 bispecific T-cell engager-armed T cells (BATs) to prevent PD-L1/PD-1 interaction and hence to redirect T cells to kill cancer cells. αPD-L1 × αCD3 bispecific T-cell engagers (BTEs) were produced from Chinese hamster ovary (CHO) cells to arm human primary T cells. Flow cytometry was used to investigate BTE binding to BATs. The cytotoxicity of BATs against PD-L1-expressing breast cancer (BC) cell lines was assessed in 2-dimensional (2D) and 3-dimensional (3D) culture models. The binding stability of BTE on BATs and their efficacy after cryopreservation were also examined. The CHO cell BTE expression yield was 3.34 mg/ml. The binding ability on T cells reached 91.02 ± 4.2 %. BATs specifically lysed PD-L1-expressing BC cells, with 56.4 ± 15.3 % HCC70 cells and 70.67 ± 15.6 % MDA-MB-231 cells lysed at a 10:1 effector-to-target ratio. BATs showed slight, nonsignificant lysis of PD-L1-negative BC cells, MCF-7, and T47D. Moreover, BATs significantly disrupted MDA-MB-231 3D spheroids expressing PD-L1 after 48 and 72 h of coculture. Cryopreserved BATs maintained BTE binding stability, cell viability, and anticancer activity, comparable to fresh BATs. αPD-L1 × αCD3 BATs induced the cytolysis of PD-L1-expressing BC cells in 2D and 3D coculture assays. BATs can be prepared and preserved, facilitating their use and transportation. This study demonstrates the potential of αPD-L1 × αCD3 BATs in treating cancers with positive PD-L1 expression.

PSGL-1 Blockade Induces Classical Activation of Human Tumor-associated Macrophages

The immune suppressive microenvironment is a major culprit for difficult-to-treat solid cancers. Particularly, inhibitory tumor-associated macrophages (TAM) define the resistant nature of the tumor milieu. To define tumor-enabling mechanisms of TAMs, we analyzed molecular clinical datasets correlating cell surface receptors with the TAM infiltrate. Though P-selectin glycoprotein ligand-1 (PSGL-1) is found on other immune cells and functions as an adhesion molecule, PSGL-1 is highly expressed on TAMs across multiple tumor types. siRNA-mediated knockdown and antibody-mediated inhibition revealed a role for PSGL-1 in maintaining an immune suppressed macrophage state. PSGL-1 knockdown or inhibition enhanced proinflammatory mediator release across assays and donors in vitro. In several syngeneic mouse models, PSGL-1 blockade alone and in combination with PD-1 blockade reduced tumor growth. Using a humanized tumor model, we observed the proinflammatory TAM switch following treatment with an anti-PSGL-1 antibody. In ex vivo patient-derived tumor cultures, a PSGL-1 blocking antibody increased expression of macrophage-derived proinflammatory cytokines, as well as IFNγ, indicative of T-cell activation. Our data demonstrate that PSGL-1 blockade reprograms TAMs, offering a new therapeutic avenue to patients not responding to T-cell immunotherapies, as well as patients with tumors devoid of T cells.

SIGNIFICANCE

This work is a significant and actionable advance, as it offers a novel approach to treating patients with cancer who do not respond to T-cell checkpoint inhibitors, as well as to patients with tumors lacking T-cell infiltration. We expect that this mechanism will be applicable in multiple indications characterized by infiltration of TAMs.

Autophagy as a Target for Non-Immune Intrinsic Functions of Programmed Cell Death-Ligand 1 in Cancer

Autophagy is a catabolic process that is essential to the maintenance of homeostasis through the cellular recycling of damaged organelles or misfolded proteins, which sustains energy balance. Additionally, autophagy plays a dual role in modulating the development and progression of cancer and inducing a survival strategy in tumoral cells. Programmed cell death-ligand 1 (PD-L1) modulates the immune response and is responsible for maintaining self-tolerance. Because tumor cells exploit the PD-L1-PD-1 interaction to subvert the immune response, immunotherapy has been developed based on the use of PD-L1-blocking antibodies. Recent evidence has suggested a bidirectional regulation between autophagy and PD-L1 molecule expression in tumor cells. Moreover, the research into the intrinsic properties of PD-L1 has highlighted new functions that are advantageous to tumor cells. The relationship between autophagy and PD-L1 is complex and still not fully understood; its effects can be context-dependent and might differ between tumoral cells. This review refines our understanding of the non-immune intrinsic functions of PD-L1 and its potential influence on autophagy, how these could allow the survival of tumor cells, and what this means for the efficacy of anti-PD-L1 therapeutic strategies.

ARF6-dependent endocytic trafficking of the Interferon-γ receptor drives adaptive immune resistance in cancer

Adaptive immune resistance (AIR) is a protective process used by cancer to escape elimination by CD8+ T cells. Inhibition of immune checkpoints PD-1 and CTLA-4 specifically target Interferon-gamma (IFNγ)-driven AIR. AIR begins at the plasma membrane where tumor cell-intrinsic cytokine signaling is initiated. Thus, plasma membrane remodeling by endomembrane trafficking could regulate AIR. Herein we report that the trafficking protein ADP-Ribosylation Factor 6 (ARF6) is critical for IFNγ-driven AIR. ARF6 prevents transport of the receptor to the lysosome, augmenting IFNγR expression, tumor intrinsic IFNγ signaling and downstream expression of immunosuppressive genes. In murine melanoma, loss of ARF6 causes resistance to immune checkpoint blockade (ICB). Likewise, low expression of ARF6 in patient tumors correlates with inferior outcomes with ICB. Our data provide new mechanistic insights into tumor immune escape, defined by ARF6-dependent AIR, and support that ARF6-dependent endomembrane trafficking of the IFNγ receptor influences outcomes of ICB.

Dual Synergistic Tumor-Specific Polymeric Nanoparticles for Efficient Chemo-Immunotherapy

Chemo-immunotherapy has made significant progress in cancer treatment. However, the cancer cell self-defense mechanisms, including cell cycle checkpoint and programmed cell death-ligand 1 (PD-L1) upregulation, have greatly hindered the therapeutic efficacy. Herein, norcantharidin (NCTD)-platinum (Pt) codelivery nanoparticles (NC-NP) with tumor-sensitive release profiles are designed to overcome the self-defense mechanisms via synergistic chemo-immunotherapy. NC-NP remains stable under normal physiological conditions but quickly releases 1,2-diaminocyclohexane-platinum(II) (DACHPt, a parent drug of oxaliplatin) and NCTD in response to the tumor acidity. NCTD inhibits protein phosphatase 2A (PP2A) activity to relieve cell cycle arrest and downregulates the tumor PD-L1 expression to disrupt the programmed cell death-1 (PD-1)/PD-L1 interaction, synergistically enhancing Pt-based chemotherapy and immunogenic cell death-induced immunotherapy. As a result, NC-NP exhibits potent synergistic cytotoxicity and promotes T cell recruitment to generate robust antitumor immune responses. The dual synergism exhibits potent antitumor activity against orthotopic 4T1 tumors, providing a promising chemo-immunotherapy paradigm for cancer treatment.

IL-17A functions and the therapeutic use of IL-17A and IL-17RA targeted antibodies for cancer treatment

Interleukin 17A (IL-17A) is a major member of the IL-17 cytokine family and is produced mainly by T helper 17 (Th17) cells. Other cells such as CD8+ T cells, γδ T cells, natural killer T cells and innate lymphoid-like cells can also produce IL-17A. In healthy individuals, IL-17A has a host-protective capacity, but excessive elevation of IL-17A is associated with the development of autoimmune diseases and cancer. Monoclonal antibodies (mAbs) targeting IL-17A (e.g., ixekizumab and secukinumab) or IL-17A receptor (IL-17RA) (e.g., brodalumab) would be investigated as potential treatments for these diseases. Currently, the application of IL-17A-targeted drugs in autoimmune diseases will provide new ideas for the treatment of tumors, and its combined application with immune checkpoint inhibitors has become a research hotspot. This article reviews the mechanism of action of IL-17A and the application of anti-IL-17A antibodies, focusing on the research progress on the mechanism of action and therapeutic blockade of IL-17A in various tumors such as colorectal cancer (CRC), lung cancer, gastric cancer and breast cancer. Moreover, we also include the results of therapeutic blockade in the field of cancer as well as recent advances in the regulation of IL-17A signaling.

Breast cancer vaccination: Latest advances with an analytical focus on clinical trials

Breast cancer (BC) is one of the main causes of cancer-related death worldwide. The heterogenicity of breast tumors and the presence of tumor resistance, metastasis, and disease recurrence make BC a challenging malignancy. A new age in cancer treatment is being ushered in by the enormous success of cancer immunotherapy, and therapeutic cancer vaccination is one such area of research. Nevertheless, it has been shown that the application of cancer vaccines in BC as monotherapy could not induce satisfying anti-tumor immunity. Indeed, the application of various vaccine platforms as well as combination therapies like immunotherapy could influence the clinical benefits of BC treatment. We analyzed the clinical trials of BC vaccination and revealed that the majority of trials were in phase I and II meaning that the BC vaccine studies lack favorable outcomes or they need more development. Furthermore, peptide- and cell-based vaccines are the major platforms utilized in clinical trials according to our analysis. Besides, some studies showed satisfying outcomes regarding carbohydrate-based vaccines in BC treatment. Recent advancements in therapeutic vaccines for breast cancer were promising strategies that could be accessible in the near future.

Ginsenosides: changing the basic hallmarks of cancer cells to achieve the purpose of treating breast cancer

In 2021, breast cancer accounted for a substantial proportion of cancer cases and represented the second leading cause of cancer deaths among women worldwide. Although tumor cells originate from normal cells in the human body, they possess distinct biological characteristics resulting from changes in gene structure and function of cancer cells in contrast with normal cells. These distinguishing features, known as hallmarks of cancer cells, differ from those of normal cells. The hallmarks primarily include high metabolic activity, mitochondrial dysfunction, and resistance to cell death. Current evidence suggests that the fundamental hallmarks of tumor cells affect the tissue structure, function, and metabolism of tumor cells and their internal and external environment. Therefore, these fundamental hallmarks of tumor cells enable tumor cells to proliferate, invade and avoid apoptosis. Modifying these hallmarks of tumor cells represents a new and potentially promising approach to tumor treatment. The key to breast cancer treatment lies in identifying the optimal therapeutic agent with minimal toxicity to normal cells, considering the specific types of tumor cells in patients. Some herbal medicines contain active ingredients which can precisely achieve this purpose. In this review, we introduce Ginsenoside's mechanism and research significance in achieving the therapeutic effect of breast cancer by changing the functional hallmarks of tumor cells, providing a new perspective for the potential application of Ginsenoside as a therapeutic drug for breast cancer.

A meta-analysis of application of PD-1/PD-L1 inhibitor-based immunotherapy in unresectable locally advanced triple-negative breast cancer

Aims: The purpose of this study was to explore the efficacy of immunotherapy for patients with triple-negative breast cancer (TNBC). Materials & methods: Randomized clinical trials comparing immunotherapy with chemotherapy for advanced TNBC patients were included. Results: A total of six articles (3183 patients) were eligible for this meta-analysis. PD-1/PD-L1 inhibitor-based immunotherapy combined with chemotherapy can significantly increase the progression-free survival (hazard ratio [HR] = 0.82; 95% CI = 0.76-1.14; p < 0.001) of unresectable locally advanced or metastatic TNBC patients without effect on overall survival, compared with chemotherapy. Conclusion: PD-1/PD-L1 inhibitors-based immunotherapy can safely improve progression-free survival in patients with unresectable locally advanced or metastatic TNBC, but has no effect on overall survival.

Immune evasion by cancer stem cells ensures tumor initiation and failure of immunotherapy

Cancer stem cells (CSCs) are a small subpopulation of cells that drive the formation and progression of tumors. However, during tumor initiation, how CSCs communicate with neighbouring immune cells to overcome the powerful immune surveillance barrier in order to form, spread, and maintain the tumor, remains poorly understood. It is, therefore, absolutely necessary to understand how a small number of tumor-initiating cells (TICs) survive immune attack during (a) the “elimination phase” of “tumor immune-editing”, (b) the establishment of regional or distant tumor after metastasis, and (c) recurrence after therapy. Mounting evidence suggests that CSCs suppress the immune system through a variety of distinct mechanisms that ensure the survival of not only CSCs but also non-stem cancer cells (NSCCs), which eventually form the tumor mass. In this review article, the mechanisms via which CSCs change the immune landscape of the tissue of origin, which contains macrophages, dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), natural killer (NK) cells, and tumor-infiltrating lymphocytes, in favour of tumorigenesis were discussed. The failure of cancer immunotherapy might also be explained by such interaction between CSCs and immune cells. This review will shed light on the critical role of CSCs in tumor immune evasion and emphasize the importance of CSC-targeted immunotherapy as a cutting-edge technique for battling cancer by restricting communication between immune cells and CSCs.

Neutrophil to Lymphocyte ratio as a predictor for immune-related adverse events in cancer patients treated with immune checkpoint inhibitors: a systematic review and meta-analysis

Background

The use of immune checkpoint inhibitors (ICIs) in cancer treatment has led to an increase in immune-related adverse events (irAEs), which can cause treatment discontinuation and even fatal reactions. The purpose of this study was to evaluate the usefulness of the peripheral biomarker neutrophil to lymphocyte ratio (NLR) in predicting irAEs.

Methods

A systematic search of databases was conducted to identify studies on the predictive value of NLR for irAEs. The standardized mean difference (SMD) was used to compare continuous NLR, while crude odds ratios (ORs) were calculated for categorized NLR if adjusted ORs and 95% confidence intervals (CIs) were not provided in the original study.

Results

The meta-analysis included 47 studies with a total of 11,491 cancer patients treated with ICIs. The baseline continuous NLR was significantly lower in patients with irAEs compared to those without (SMD=-1.55, 95%CI=-2.64 to -0.46, P=0.006). Similarly, categorized NLR showed that lower baseline NLR was associated with increased irAEs (OR=0.55, 95%CI=0.41-0.73, P<0.001). Subgroup analysis revealed that the OR for predicting irAEs with NLR cut-off values of 3 and 5 was 0.4 and 0.59, respectively. Interestingly, increased baseline NLR was associated with a higher incidence of immune-related liver injury (OR=2.44, 95%CI=1.23-4.84, I2 = 0%, P=0.010).

Conclusion

Our study suggests that lower baseline NLR is associated with a higher risk of overall irAEs. However, further studies are needed to determine the best cut-off value and explore the efficacy of NLR in predicting specific types of irAEs.

Metabolites and Immune Response in Tumor Microenvironments

The remodeled cancer cell metabolism affects the tumor microenvironment and promotes an immunosuppressive state by changing the levels of macro- and micronutrients and by releasing hormones and cytokines that recruit immunosuppressive immune cells. Novel dietary interventions such as amino acid restriction and periodic fasting mimicking diets can prevent or dampen the formation of an immunosuppressive microenvironment by acting systemically on the release of hormones and growth factors, inhibiting the release of proinflammatory cytokines, and remodeling the tumor vasculature and extracellular matrix. Here, we discuss the latest research on the effects of these therapeutic interventions on immunometabolism and tumor immune response and future scenarios pertaining to how dietary interventions could contribute to cancer therapy.

Overcoming acquired resistance to cancer immune checkpoint therapy: potential strategies based on molecular mechanisms

Immune checkpoint inhibitors (ICIs) targeting CTLA-4 and PD-1/PD-L1 to boost tumor-specific T lymphocyte immunity have opened up new avenues for the treatment of various histological types of malignancies, with the possibility of durable responses and improved survival. However, the development of acquired resistance to ICI therapy over time after an initial response remains a major obstacle in cancer therapeutics. The potential mechanisms of acquired resistance to ICI therapy are still ambiguous. In this review, we focused on the current understanding of the mechanisms of acquired resistance to ICIs, including the lack of neoantigens and effective antigen presentation, mutations of IFN-γ/JAK signaling, and activation of alternate inhibitory immune checkpoints, immunosuppressive tumor microenvironment, epigenetic modification, and dysbiosis of the gut microbiome. Further, based on these mechanisms, potential therapeutic strategies to reverse the resistance to ICIs, which could provide clinical benefits to cancer patients, are also briefly discussed.

Clinical Importance of the lncRNA NEAT1 in Cancer Patients Treated with Immune Checkpoint Inhibitors

PURPOSE

mAbs targeting the PD-1/PD-L1 immune checkpoint are powerful tools to improve the survival of patients with cancer. Understanding the molecular basis of clinical response to these treatments is critical to identify patients who can benefit from this immunotherapy. In this study, we investigated long noncoding RNA (lncRNA) expression in patients with cancer treated with anti-PD-1/PD-L1 immunotherapy.

EXPERIMENTAL DESIGN

lncRNA expression profile was analyzed in one cohort of patients with melanoma and two independent cohorts of patients with glioblastoma (GBM) undergoing anti-PD-1/PD-L1 immunotherapy. Single-cell RNA-sequencing analyses were performed to evaluate lncRNA expression in tumor cells and tumor-infiltrating immune cells.

RESULTS

We identified the lncRNA NEAT1 as commonly upregulated between patients with melanoma with complete therapeutic response and patients with GBM with longer survival following anti-PD-1/PD-L1 treatment. Gene set enrichment analyses revealed that NEAT1 expression was strongly associated with the IFNγ pathways, along with downregulation of cell-cycle-related genes. Single-cell RNA-sequencing analyses revealed NEAT1 expression across multiple cell types within the GBM microenvironment, including tumor cells, macrophages, and T cells. High NEAT1 expression levels in tumor cells correlated with increased infiltrating macrophages and microglia. In these tumor-infiltrating myeloid cells, we found that NEAT1 expression was linked to enrichment in TNFα/NFκB signaling pathway genes. Silencing NEAT1 suppressed M1 macrophage polarization and reduced the expression of TNFα and other inflammatory cytokines.

CONCLUSIONS

These findings suggest an association between NEAT1 expression and patient response to anti-PD-1/PD-L1 therapy in melanoma and GBM and have important implications for the role of lncRNAs in the tumor microenvironment.

Iron-mediated oxidative stress induces PD-L1 expression via activation of c-Myc in lung adenocarcinoma

Introduction: The PD-1/PD-L1 axis is hijacked by lung adenocarcinoma (LUAD) cells to escape immune surveillance. PD-L1 expression in LUAD is affected, among others, by the metabolic trafficking between tumor cells and the tumor microenvironment (TME). Methods: Correlation between PD-L1 expression and iron content within the TME was established on FFPE LUAD tissue samples. The effects of an iron rich microenvironment on PD-L1 mRNA and protein levels were assessed in vitro in H460 and A549 LUAD by using qPCR, western blot and flow citometry. c-Myc knockdown was performed to validate the role of this transcription factor on PD-L1 expression. The effects of iron-induced PD-L1 on T cell immune function was assessed by quantifying IFN-γ release in a co-colture system. TCGA dataset was used to analyse the correlation between PD-L1 and CD71 mRNA expression in LUAD patients. Results: In this study, we highlight a significant correlation between iron density within the TME and PD-L1 expression in 16 LUAD tissue specimens. In agreement, we show that a more pronounced innate iron-addicted phenotype, indicated by a higher transferrin receptor CD71 levels, significantly correlates with higher PD-L1 mRNA expression levels in LUAD dataset obtained from TCGA database. In vitro, we demonstrate that the addition of Fe³⁺ within the culture media promotes the significant overexpression of PD-L1 in A549 and H460 LUAD cells, through the modulation of its gene transcription mediated by c-Myc. The effects of iron lean on its redox activity since PD-L1 up-regulation is counteracted by treatment with the antioxidant compound trolox. When LUAD cells are co-cultured with CD3/CD28-stimulated T cells in an iron-rich culture condition, PD-L1 up-regulation causes the inhibition of T-lymphocytes activity, as demonstrated by the significant reduction of IFN-γ release. Discussion: Overall, in this study we demonstrate that iron abundance within the TME may enhance PD-L1 expression in LUAD and, thus, open the way for the identification of possible combinatorial strategies that take into account the iron levels within the TME to improve the outcomes of LUAD patients treated with anti-PD-1/PD-L1-based therapies.

Overcoming Resistance to Immune Checkpoint Inhibitor Therapy Using Calreticulin-Inducing Nanoparticle

Nanoparticles (NPs) have the ability to transform poorly immunogenic tumors into activated 'hot' targets. In this study, we investigated the potential of a liposome-based nanoparticle (CRT-NP) expressing calreticulin as an in-situ vaccine to restore sensitivity to anti-CTLA4 immune checkpoint inhibitor (ICI) in CT26 colon tumors. We found that a CRT-NP with a hydrodynamic diameter of approximately 300 nm and a zeta potential of approximately +20 mV induced immunogenic cell death (ICD) in CT-26 cells in a dose-dependent manner. In the mouse model of CT26 xenograft tumors, both CRT-NP and ICI monotherapy caused moderate reductions in tumor growth compared to the untreated control group. However, the combination therapy of CRT-NP and anti-CTLA4 ICI resulted in remarkable suppression of tumor growth rates (>70%) compared to untreated mice. This combination therapy also reshaped the tumor microenvironment (TME), achieving the increased infiltration of antigen-presenting cells (APCs) such as dendritic cells and M1 macrophages, as well as an abundance of T cells expressing granzyme B and a reduction in the population of CD4+ Foxp3 regulatory cells. Our findings indicate that CRT-NPs can effectively reverse immune resistance to anti-CTLA4 ICI therapy in mice, thereby improving the immunotherapeutic outcome in the mouse model.

TCGA RNA-Seq and Tumor-Infiltrating Lymphocyte Imaging Data Reveal Cold Tumor Signatures of Invasive Ductal Carcinomas and Estrogen Receptor-Positive Human Breast Tumors

Comparative studies of immune-active hot and immune-deserted cold tumors are critical for identifying therapeutic targets and strategies to improve immunotherapy outcomes in cancer patients. Tumors with high tumor-infiltrating lymphocytes (TILs) are likely to respond to immunotherapy. We used the human breast cancer RNA-seq data from the cancer genome atlas (TCGA) and classified them into hot and cold tumors based on their lymphocyte infiltration scores. We compared the immune profiles of hot and cold tumors, their corresponding normal tissue adjacent to the tumor (NAT), and normal breast tissues from healthy individuals from the Genotype-Tissue Expression (GTEx) database. Cold tumors showed a significantly lower effector T cells, lower levels of antigen presentation, higher pro-tumorigenic M2 macrophages, and higher expression of extracellular matrix (ECM) stiffness-associated genes. Hot/cold dichotomy was further tested using TIL maps and H&E whole-slide pathology images from the cancer imaging archive (TCIA). Analysis of both datasets revealed that infiltrating ductal carcinoma and estrogen receptor ER-positive tumors were significantly associated with cold features. However, only TIL map analysis indicated lobular carcinomas as cold tumors and triple-negative breast cancers (TNBC) as hot tumors. Thus, RNA-seq data may be clinically relevant to tumor immune signatures when the results are supported by pathological evidence.

Genomic hallmarks and therapeutic implications of G0 cell cycle arrest in cancer

BACKGROUND

Therapy resistance in cancer is often driven by a subpopulation of cells that are temporarily arrested in a non-proliferative G0 state, which is difficult to capture and whose mutational drivers remain largely unknown.

RESULTS

We develop methodology to robustly identify this state from transcriptomic signals and characterise its prevalence and genomic constraints in solid primary tumours. We show that G0 arrest preferentially emerges in the context of more stable, less mutated genomes which maintain TP53 integrity and lack the hallmarks of DNA damage repair deficiency, while presenting increased APOBEC mutagenesis. We employ machine learning to uncover novel genomic dependencies of this process and validate the role of the centrosomal gene CEP89 as a modulator of proliferation and G0 arrest capacity. Lastly, we demonstrate that G0 arrest underlies unfavourable responses to various therapies exploiting cell cycle, kinase signalling and epigenetic mechanisms in single-cell data.

CONCLUSIONS

We propose a G0 arrest transcriptional signature that is linked with therapeutic resistance and can be used to further study and clinically track this state.

Tackling of Immunorefractory Tumors by Targeting Alternative Immune Checkpoints

Physiologically, well known or traditional immune checkpoints (ICs), such as CTLA-4 and PD-1, are in place to promote tolerance to self-antigens and prevent generation of autoimmunity. In cancer, the ICs are effectively engaged by the tumor cells or stromal ells from the tumor microenvironment through expression of cognate ligands for the ICs present on the cell surface of CD8+ T lymphocytes. The ligation of ICs on CD8+ T lymphocytes triggers inhibitory signaling pathways, leading to quiescence or an exhaustion of CD8+ T lymphocytes. This results in failure of immunotherapy. To overcome this, several FDA-approved therapeutic antibodies are available, but the clinical outcome is quite variable due to the resistance encountered through upregulated expression of alternate ICs such as VISTA, LAG-3, TIGIT and TIM-3. This review focuses on the roles played by the traditional as well as alternate ICs and the contribution of associated signaling pathways in generating such resistance to immunotherapy. Combinatorial targeting of traditional and alternate ICs might be beneficial for immune-refractory tumors.

Predictive impact of prognostic nutritional index in patients with cancer treated with immune checkpoint inhibitors: a systematic review and meta-analysis

A few previous studies have investigated the prognostic value of the prognostic nutritional index (PNI) in patients treated with immune checkpoint inhibitors (ICIs); however, the results are inconsistent. Therefore, this study aimed to clarify the prognostic significance of PNI. The PubMed, Embase, and Cochrane Library databases were searched. A meta-analysis of the impact of PNI on overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and rate of adverse events (AEs) in patients treated with ICIs was performed. Twenty-three studies involving 2,386 patients were included. Low PNI was associated with significantly poor OS (hazard ratio [HR] = 2.26, 95% confidence interval [CI]: 1.81-2.82, P < .001) and short PFS (HR = 1.75, 95% CI: 1.54-1.99, P < .001). Patients with low PNI tended to have a low ORR (odds ratio [OR] = 0.47, 95% CI: 0.34-0.65, P < .001) and DCR (OR = 0.43, 95% CI: 0.34-0.56, P < .001). However, the subgroup analysis demonstrated no significant association between PNI and survival time in patients receiving a programmed death ligand-1 inhibitor. PNI was significantly associated with survival time and treatment efficacy in patients treated with ICIs.

CD47KO/CRT dual-bioengineered cell membrane-coated nanovaccine combined with anti-PD-L1 antibody for boosting tumor immunotherapy

Tumor vaccines trigger tumor-specific immune responses to prevent or treat tumors by activating the hosts' immune systems, and therefore, these vaccines have potential clinical applications. However, the low immunogenicity of the tumor antigen itself and the low efficiency of the vaccine delivery system hinder the efficacy of tumor vaccines that cannot produce high-efficiency and long-lasting antitumor immune effects. Here, we constructed a nanovaccine by integrating CD47KO/CRT dual-bioengineered B16F10 cancer cell membranes and the unmethylated cytosine-phosphate-guanine (CpG) adjuvant. Hyperbranched PEI25k was used to load unmethylated cytosine-phosphate-guanine (CpG) through electrostatic adsorption to prepare PEI25k/CpG nanoparticles (PEI25k/CpG-NPs). CD47KO/CRT dual-bioengineered cells were obtained by CRISPR-Cas9 gene editing technology, followed by the cell surface translocation of calreticulin (CRT) to induce immunogenic cell death (ICD) in vitro. Finally, the extracted cell membranes were coextruded with PEI25k/CpG-NPs to construct the CD47KO/CRT dual-bioengineered cancer cell membrane-coated nanoparticles (DBE@CCNPs). DBE@CCNPs could promote endocytosis of antigens and adjuvants in murine bone marrow derived dendritic cells (BMDCs) and induce their maturation and antigen cross-presentation. To avoid immune checkpoint molecule-induced T cell dysfunction, the immune checkpoint inhibitor, the anti-PD-L1 antibody, was introduced to boost tumor immunotherapy through a combination with the DBE@CCNPs nanovaccine. This combination therapy strategy can significantly alleviate tumor growth and may open up a potential strategy for clinical tumor immunotherapy.

Treatment with decitabine induces the expression of stemness markers, PD-L1 and NY-ESO-1 in colorectal cancer: potential for combined chemoimmunotherapy

BACKGROUND

The mechanism of tumor immune escape and progression in colorectal cancer (CRC) is widely investigated in-vitro to help understand and identify agents that might play a crucial role in response to treatment and improve the overall survival of CRC patients. Several mechanisms of immune escape and tumor progression, including expression of stemness markers, inactivation of immunoregulatory genes by methylation, and epigenetic silencing, have been reported in CRC, indicating the potential of demethylating agents as anti-cancer drugs. Of these, a chemotherapeutic demethylating agent, Decitabine (DAC), has been reported to induce a dual effect on both DNA demethylation and histone changes leading to an increased expression of target biomarkers, thus making it an attractive anti-tumorigenic drug.

METHODS

We compared the effect of DAC in primary 1076 Col and metastatic 1872 Col cell lines isolated and generated from patients' tumor tissues. Both cell lines were treated with DAC, and the expression of the NY-ESO-1 cancer-testis antigen, the PD-L1 immunoinhibitory marker, and the CD44, Nanog, KLF-4, CD133, MSI-1 stemness markers were analyzed using different molecular and immunological assays.

RESULTS

DAC treatment significantly upregulated stemness markers in both primary 1076 Col and meta-static 1872 Col cell lines, although a lower effect occurred on the latter: CD44 (7.85 fold; ***p = 0.0001 vs. (4.19 fold; *p = 0.0120), Nanog (4.1 fold; ***p < 0.0001 vs.1.69 fold; ***p = 0.0008), KLF-4 (4.33 fold; ***p < 0.0001 vs.2.48 fold; ***p = 0.0005), CD133 (16.77 fold; ***p = 0.0003 vs.6.36 fold; *p = 0.0166), and MSI-1 (2.33 fold; ***p = 0.0003 vs.2.3 fold; ***p = 0.0004), respectively. Interestingly, in the metastatic 1872 Col cells treated with DAC, the expression of both PD-L1 and NY-ESO-1 was increased tenfold (*p = 0.0128) and fivefold (***p < 0.0001), respectively.

CONCLUSIONS

We conclude that the upregulation of both stemness and immune checkpoint markers by DAC treatment on CRC cells might represent a mechanism of immune evasion. In addition, induction of NY-ESO-1 may represent an immuno-therapeutic option in metastatic CRC patients. Finally, the combination of DAC and anti-PD-1/anti-PD-L1 antibodies treatment should represent a potential therapeutic intervention for this group of patients.

Novel extracellular role of REIC/Dkk-3 protein in PD-L1 regulation in cancer cells

The adenovirus-REIC/Dkk-3 expression vector (Ad-REIC) has been the focus of numerous clinical studies due to its potential for the quenching of cancers. The cancer-suppressing mechanisms of the REIC/DKK-3 gene depend on multiple pathways that exert both direct and indirect effects on cancers. The direct effect is triggered by REIC/Dkk-3-mediated ER stress that causes cancer-selective apoptosis, and the indirect effect can be classified in two ways: (i) induction, by Ad-REIC-mis-infected cancer-associated fibroblasts, of the production of IL-7, an important activator of T cells and NK cells, and (ii) promotion, by the secretory REIC/Dkk-3 protein, of dendritic cell polarization from monocytes. These unique features allow Ad-REIC to exert effective and selective cancer-preventative effects in the manner of an anticancer vaccine. However, the question of how the REIC/Dkk-3 protein leverages anticancer immunity has remained to be answered. We herein report a novel function of the extracellular REIC/Dkk-3-namely, regulation of an immune checkpoint via modulation of PD-L1 on the cancer-cell surface. First, we identified novel interactions of REIC/Dkk-3 with the membrane proteins C5aR, CXCR2, CXCR6, and CMTM6. These proteins all functioned to stabilize PD-L1 on the cell surface. Due to the dominant expression of CMTM6 among the proteins in cancer cells, we next focused on CMTM6 and observed that REIC/Dkk-3 competed with CMTM6 for PD-L1, thereby liberating PD-L1 from its complexation with CMTM6. The released PD-L1 immediately underwent endocytosis-mediated degradation. These results will enhance our understanding of not only the physiological nature of the extracellular REIC/Dkk-3 protein but also the Ad-REIC-mediated anticancer effects. KEY MESSAGES: • REIC/Dkk-3 protein effectively suppresses breast cancer progression through an acceleration of PD-L1 degradation. • PD-L1 stability on the cancer cell membrane is kept high by binding with mainly CMTM6. • Competitive binding of REIC/Dkk-3 protein with CMTM6 liberates PD-L1, leading to PD-L1 degradation.

Transient Receptor Potential Vanilloid 4: a Double-Edged Sword in the Central Nervous System

Transient receptor potential vanilloid 4 (TRPV4) is a nonselective cation channel that can be activated by diverse stimuli, such as heat, mechanical force, hypo-osmolarity, and arachidonic acid metabolites. TRPV4 is widely expressed in the central nervous system (CNS) and participates in many significant physiological processes. However, accumulative evidence has suggested that deficiency, abnormal expression or distribution, and overactivation of TRPV4 are involved in pathological processes of multiple neurological diseases. Here, we review the latest studies concerning the known features of this channel, including its expression, structure, and its physiological and pathological roles in the CNS, proposing an emerging therapeutic strategy for CNS diseases.

Molecular and functional imaging in cancer-targeted therapy: current applications and future directions

Targeted anticancer drugs block cancer cell growth by interfering with specific signaling pathways vital to carcinogenesis and tumor growth rather than harming all rapidly dividing cells as in cytotoxic chemotherapy. The Response Evaluation Criteria in Solid Tumor (RECIST) system has been used to assess tumor response to therapy via changes in the size of target lesions as measured by calipers, conventional anatomically based imaging modalities such as computed tomography (CT), and magnetic resonance imaging (MRI), and other imaging methods. However, RECIST is sometimes inaccurate in assessing the efficacy of targeted therapy drugs because of the poor correlation between tumor size and treatment-induced tumor necrosis or shrinkage. This approach might also result in delayed identification of response when the therapy does confer a reduction in tumor size. Innovative molecular imaging techniques have rapidly gained importance in the dawning era of targeted therapy as they can visualize, characterize, and quantify biological processes at the cellular, subcellular, or even molecular level rather than at the anatomical level. This review summarizes different targeted cell signaling pathways, various molecular imaging techniques, and developed probes. Moreover, the application of molecular imaging for evaluating treatment response and related clinical outcome is also systematically outlined. In the future, more attention should be paid to promoting the clinical translation of molecular imaging in evaluating the sensitivity to targeted therapy with biocompatible probes. In particular, multimodal imaging technologies incorporating advanced artificial intelligence should be developed to comprehensively and accurately assess cancer-targeted therapy, in addition to RECIST-based methods.

Cross-talk between cancer stem cells and immune cells: potential therapeutic targets in the tumor immune microenvironment

Ongoing research has revealed that the existence of cancer stem cells (CSCs) is one of the biggest obstacles in the current cancer therapy. CSCs make an influential function in tumor progression, recurrence and chemoresistance due to their typical stemness characteristics. CSCs are preferentially distributed in niches, and those niche sites exhibit characteristics typical of the tumor microenvironment (TME). The complex interactions between CSCs and TME illustrate these synergistic effects. The phenotypic heterogeneity within CSCs and the spatial interactions with the surrounding tumor microenvironment led to increased therapeutic challenges. CSCs interact with immune cells to protect themselves against immune clearance by exploiting the immunosuppressive function of multiple immune checkpoint molecules. CSCs also can protect themselves against immune surveillance by excreting extracellular vesicles (EVs), growth factors, metabolites and cytokines into the TME, thereby modulating the composition of the TME. Therefore, these interactions are also being considered for the therapeutic development of anti-tumor agents. We discuss here the immune molecular mechanisms of CSCs and comprehensively review the interplay between CSCs and the immune system. Thus, studies on this topic seem to provide novel ideas for reinvigorating therapeutic approaches to cancer.

Mutant P53 in the formation and progression of the tumor microenvironment: Friend or foe

TP53 is the most frequently mutated gene in human cancer. It encodes the tumor suppressor protein p53, which suppresses tumorigenesis by acting as a critical transcription factor that can induce the expression of many genes controlling a plethora of fundamental cellular processes, including cell cycle progression, survival, apoptosis, and DNA repair. Missense mutations are the most frequent type of mutations in the TP53 gene. While these can have variable effects, they typically impair p53 function in a dominant-negative manner, thereby altering intra-cellular signaling pathways and promoting cancer development. Additionally, it is becoming increasingly apparent that p53 mutations also have non-cell autonomous effects that influence the tumor microenvironment (TME). The TME is a complex and heterogeneous milieu composed of both malignant and non-malignant cells, including cancer-associated fibroblasts (CAFs), adipocytes, pericytes, different immune cell types, such as tumor-associated macrophages (TAMs) and T and B lymphocytes, as well as lymphatic and blood vessels and extracellular matrix (ECM). Recently, a large body of evidence has demonstrated that various types of p53 mutations directly affect TME. They fine-tune the inflammatory TME and cell fate reprogramming, which affect cancer progression. Notably, re-educating the p53 signaling pathway in the TME may be an effective therapeutic strategy in combating cancer. Therefore, it is timely to here review the recent advances in our understanding of how TP53 mutations impact the fate of cancer cells by reshaping the TME.

GPX3 expression was down-regulated but positively correlated with poor outcome in human cancers

Introduction

Cancer is a crucial public health problem and one of the leading causes of death worldwide. Previous studies have suggested that GPX3 may be involved in cancer metastasis and chemotherapy resistance. However, how GPX3 affects cancer patients' outcomes and the underlying mechanism remains unclear.

Methods

Sequencing data and clinical data from TCGA, GTEx, HPA, and CPTAC were used to explore the relationship between GPX3 expression and clinical features. Immunoinfiltration scores were used to assess the relationship between GPX3 and the tumor immune microenvironment. Functional enrichment analysis was used to predict the role of GPX3 in tumors. Gene mutation frequency, methylation level, and histone modification were used to predict the GPX3 expression regulation method. Breast, ovarian, colon, and gastric cancer cells were used to investigate the relationship between GPX3 expression and cancer cell metastasis, proliferation, and chemotherapy sensitivity.

Results

GPX3 is down-regulated in various tumor tissues, and GPX3 expression level can be used as a marker for cancer diagnosis. However, GPX3 expression is associated with higher stage and lymph node metastasis, as well as poorer prognosis. GPX3 is closely related to thyroid function and antioxidant function, and its expression may be regulated by epigenetic inheritance such as methylation modification or histone modification. In vitro experiments, GPX3 expression is associated with cancer cell sensitivity to oxidant and platinum-based chemotherapy and is involved in tumor metastasis in oxidative environments.

Discussion

We explored the relationship between GPX3 and clinical features, immune infiltration characteristics, migration and metastasis, and chemotherapy sensitivities of human cancers. We further investigated the potential genetic and epigenetic regulation of GPX3 in cancer. Our results suggested that GPX3 plays a complicated role in the tumor microenvironment, simultaneously promoting metastasis and chemotherapy resistance in human cancers.

Interleukin-34 and immune checkpoint inhibitors: Unified weapons against cancer

Interleukin-34 (IL-34) is a cytokine that is involved in the regulation of immune cells, including macrophages, in the tumor microenvironment (TME). Macrophages are a type of immune cell that can be found in large numbers within the TME and have been shown to have a role in the suppression of immune responses in cancer. This mmune suppression can contribute to cancer development and tumors' ability to evade the immune system. Immune checkpoint inhibitors (ICIs) are a type of cancer treatment that target proteins on immune cells that act as "checkpoints," regulating the activity of the immune system. Examples of these proteins include programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). ICIs work by blocking the activity of these proteins, allowing the immune system to mount a stronger response against cancer cells. The combination of IL-34 inhibition with ICIs has been proposed as a potential treatment option for cancer due to the role of IL-34 in the TME and its potential involvement in resistance to ICIs. Inhibiting the activity of IL-34 or targeting its signaling pathways may help to overcome resistance to ICIs and improve the effectiveness of these therapies. This review summarizes the current state of knowledge concerning the involvement of IL-34-mediated regulation of TME and the promotion of ICI resistance. Besides, this work may shed light on whether targeting IL-34 might be exploited as a potential treatment option for cancer patients in the future. However, further research is needed to fully understand the mechanisms underlying the role of IL-34 in TME and to determine the safety and efficacy of this approach in cancer patients.

A comprehensive analysis of mRNA expression profiles of Esophageal Squamous Cell Carcinoma reveals downregulation of Desmoglein 1 and crucial genomic targets

AIM

Esophageal Squamous Cell Carcinoma (ESCC) is a histological subtype of esophageal cancer that begins in the squamous cells in the esophagus. In only 19% of the ESCC-diagnosed patients, a five-year survival rate has been seen. This necessitates the identification of high-confidence biomarkers for early diagnosis, prognosis, and potential therapeutic targets for the mitigation of ESCC.

METHOD

We performed a meta-analysis of 10 mRNA datasets and identified consistently perturbed genes across the studies. Then, integrated with ESCC ATLAS to segregate 'core' genes to identify consequences of primary gene perturbation events leading to gene-gene interactions and dysregulated molecular signaling pathways. Further, by integrating with toxicogenomics data, inferences were drawn for gene interaction with environmental exposures, trace elements, chemical carcinogens, and drug chemicals. We also deduce the clinical outcomes of candidate genes based on survival analysis using the ESCC related dataset in The Cancer Genome Atlas.

RESULT

We identified 237 known and 18 novel perturbed candidate genes. Desmoglein 1 (DSG1) is one such gene that we found significantly downregulated (Fold Change =-1.89, p-value = 8.2e-06) in ESCC across six different datasets. Further, we identified 31 'core' genes (that either harbor genetic variants or are regulated by epigenetic modifications) and found regulating key biological pathways via adjoining genes in gene-gene interaction networks. Functional enrichment analysis showed dysregulated biological processes and pathways including "Extracellular matrix", "Collagen trimmer" and "HPV infection" are significantly overrepresented in our candidate genes. Based on the toxicogenomic inferences from Comparative Toxicogenomics Database we report the key genes that interacted with risk factors such as tobacco smoking, zinc, nitroso benzylmethylamine, and drug chemicals such as cisplatin, Fluorouracil, and Mitomycin in relation to ESCC. We also point to the STC2 gene that shows a high risk for mortality in ESCC patients.

CONCLUSION

We identified novel perturbed genes in relation to ESCC and explored their interaction network. DSG1 is one such gene, its association with microbiota and a clinical presentation seen commonly with ESCC hints that it is a good candidate for early diagnostic marker. Besides, in this study we highlight candidate genes and their molecular connections to risk factors, biological pathways, drug chemicals, and the survival probability of ESCC patients.

High tissue expression of TLRs combined with high density of tumor infiltrating lymphocytes predicts a better prognosis in colorectal cancer patients

BACKGROUND

Colorectal cancer causes 935,000 cancer deaths yearly. High local immune cell infiltration serves as a positive prognostic factor in CRC. Toll-like receptors (TLRs) induce innate immune responses and lead to adaptive immune system activation. TLRs play protumorigenic and antitumorigenic roles. We aimed to explore the relationship between TLR immunoexpressions and the infiltration densities of T-lymphocytes in CRC.

METHODS

Immunohistochemical TLR2, TLR4, TLR5, and TLR7 positivity and the density of CD3- and CD8-positive cells in tumoral and stromal tissue were evaluated from the tissue microarray slides of 549 consecutive CRC surgical patients treated at Helsinki University Hospital, Finland, between 1998 and 2005. We calculated the associations and correlations using Pearson's chi-square and Spearman's correlation tests, generating survival curves using the Kaplan-Meier method.

RESULTS

Positive intratumoral CD3 and CD8 densities associated with a high TLR2 expression (p < 0.001 and p = 0.001, respectively) and a high TLR4 expression (p = 0.013 and p = 0.025). A low TLR5 immunoexpression associated with negative intratumoral CD3 (p = 0.001) and CD8 (p = 0.011) and a low stromal CD3 (p = 0.001). No association or correlation emerged between TLR7 immunoexpression and CD3 or CD8 cell density. A low CD3-CD8 tumor-stroma index indicated a worse prognosis among all TLR subgroups, except the TLR7-negative subgroup.

CONCLUSIONS

We detected significant associations and correlations between high tissue TLR2, TLR4, and TLR5 immunoexpressions and high densities of CD3- and CD8-positive cells. Combining these markers may improve the prognostic evaluation of CRC patients.

Low-dose anti-VEGFR2 therapy promotes anti-tumor immunity in lung adenocarcinoma by down-regulating the expression of layilin on tumor-infiltrating CD8+T cells

PURPOSE

Our study intended to explore how low-dose anti-angiogenic drugs affected anti-tumor immunity of tumor-infiltrating exhausted CD8⁺T cells and achieved better clinical response when combined with immunotherapy. We set out to find potential targets or predictive biomarker on CD8⁺T cells for immunotherapy.

METHODS

We tested different doses of anti-VEGFR2 antibody combined with anti-PD1 antibody to treat LUAD in vivo and analyzed tumor-infiltrating CD8⁺T cells by flow cytometry. CD8⁺T cells overexpressing LAYN were co-cultured with LA795 cell lines to identify the function of LAYN in CD8⁺T cells. We also analyzed clinical samples from advanced LUAD patients treated with anti-angiogenesis therapy combined with immunotherapy.

RESULTS

Low-dose anti-VEGFR2 antibody combined with anti-PD1 antibody treatment delayed tumor growth and prolonged the survival time of tumor-bearing mice. The number of tumor-infiltrating CD8⁺T cells was reduced and the expression of LAYN was down-regulated in tumor-infiltrating CD8⁺T cells in the low-dose anti-VEGFR2 combination group. It was found that LAYN inhibited the killing function of CD8⁺T cells. In patients with advanced LUAD who received anti-angiogenesis therapy combined with immunotherapy, the LAYN⁺CD8⁺T cell subpopulation in good responders was significantly higher than that in poor responders. Furthermore, we demonstrated the expression of LAYN was regulated by upstream transcription factor NR4A1.

CONCLUSION

Low-dose anti-VEGFR2 antibody combined with anti-PD1 antibody therapy promoted anti-tumor immunity and the downregulation of LAYN in tumor-infiltrating CD8⁺T cells played an important role in this process. These findings had implications for improving the efficacy of immune checkpoint blockade therapy and further optimized clinical treatment guidelines in advanced LUAD.

Decoding molecular programs in melanoma brain metastases

Melanoma brain metastases (MBM) variably respond to therapeutic interventions; thus determining patient's prognosis. However, the mechanisms that govern therapy response are poorly understood. Here, we use a multi-OMICS approach and targeted sequencing (TargetSeq) to unravel the programs that potentially control the development of progressive intracranial disease. Molecularly, the expression of E-cadherin (Ecad) or NGFR, the BRAF mutation state and level of immune cell infiltration subdivides tumors into proliferative/pigmented and invasive/stem-like/therapy-resistant irrespective of the intracranial location. The analysis of MAPK inhibitor-naive and refractory MBM reveals switching from Ecad-associated into NGFR-associated programs during progression. NGFR-associated programs control cell migration and proliferation via downstream transcription factors such as SOX4. Moreover, global methylome profiling uncovers 46 differentially methylated regions that discriminate BRAF^mut and wildtype MBM. In summary, we propose that the expression of Ecad and NGFR sub- classifies MBM and suggest that the Ecad-to-NGFR phenotype switch is a rate-limiting process which potentially indicates drug-response and intracranial progression states in melanoma patients.

Tumor Treating Fields (TTFields) Concomitant with Immune Checkpoint Inhibitors Are Therapeutically Effective in Non-Small Cell Lung Cancer (NSCLC) In Vivo Model

Tumor Treating Fields (TTFields) are electric fields that exert physical forces to disrupt cellular processes critical for cancer cell viability and tumor progression. TTFields induce anti-mitotic effects through the disruption of the mitotic spindle and abnormal chromosome segregation, which trigger several forms of cell death, including immunogenic cell death (ICD). The efficacy of TTFields concomitant with anti-programmed death-1 (anti-PD-1) treatment was previously shown in vivo and is currently under clinical investigation. Here, the potential of TTFields concomitant with anti- PD-1/anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) or anti-programmed death-ligand 1 (anti-PD-L1) immune checkpoint inhibitors (ICI) to improve therapeutic efficacy was examined in lung tumor-bearing mice. Increased circulating levels of high mobility group box 1 protein (HMGB1) and elevated intratumoral levels of phosphorylated eukaryotic translation initiation factor 2α (p-eIF2α) were found in the TTFields-treated mice, indicative of ICD induction. The concomitant application of TTFields and ICI led to a significant decrease in tumor volume as compared to all other groups. In addition, significant increases in the number of tumor-infiltrating immune cells, specifically cytotoxic T-cells, were observed in the TTFields plus anti-PD-1/anti-CTLA-4 or anti-PD-L1 groups. Correspondingly, cytotoxic T-cells isolated from these tumors showed higher levels of IFN-γ production. Collectively, these results suggest that TTFields have an immunoactivating role that may be leveraged for concomitant treatment with ICI to achieve better tumor control by enhancing antitumor immunity.

Vessel state and immune infiltration of the angiogenesis subgroup and construction of a prediction model in osteosarcoma

Angiogenesis has been recognized as a pivotal contributor to tumorigenesis and progression. However, the role of angiogenesis-related genes (ARGs) in vessel state, immune infiltration, and prognosis remains unknown in osteosarcoma (OS). Bulk RNA sequencing data of osteosarcoma patients were obtained from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database, and patients were divided into two angiogenesis subgroups according to the expression of ARGs. We compared their vessel state and used two independent algorithms to evaluate the tumor microenvironment (TME) in the two subgroups. Furthermore, hub genes of differentially expressed genes (DEGs) in the two subgroups were selected to perform LASSO regression and multivariate Cox stepwise regression, and two prognostic hub genes were found. An ARG_score based on prognostic hub genes was calculated and proved to be reliable in the overall survival prediction in OS patients. Furthermore, the ARG_score was significantly associated with ARGs, immune infiltration, response to immunotherapy, and drug sensitivity. To make our prediction model perform well, clinical features were added and a highly accurate interactive nomogram was constructed. Immunohistochemistry and qRT-PCR were utilized to verify the expression of prognostic hub genes. GSE21257 from the Gene Expression Omnibus (GEO) database was used as a validation dataset to verify its robustness. In conclusion, our comprehensive analysis of angiogenesis subgroups in OS illustrated that angiogenesis may lead to different vessel states and further affect immune infiltration and prognosis of OS patients. Our findings may bring a novel perspective for the immunotherapy strategies for OS patients.