PI3Kγ stimulates a high molecular weight form of myosin light chain kinase to promote myeloid cell adhesion and tumor inflammation

One Step Ahead: Preventing Tumor Adaptation to Immune Therapy

Immune checkpoint inhibitors are cancer therapeutics that have shown remarkable success in extending lives in many cancers, including melanoma, MSI-high cancers, and other cancers. However, these therapeutics have not shown benefit for many patients with cancer, especially those with advanced cancer diagnoses. In addition, many patients develop resistance to these therapeutics and/or life-altering adverse events that can include cardiotoxicity, pneumonitis, thyroiditis, pancreatitis, and hepatitis. Extensive efforts to improve cancer care by uncovering mechanisms of resistance to immune therapy in solid tumors have led to identification of new sources of resistance and to the development of new approaches to activate or sustain antitumor immunity. Chronic stimulation of T cells by tumors and by checkpoint inhibitors can lead to a progressive state of T-cell exhaustion. Chronic T-cell activation by the tumor microenvironment (TME) or immune therapeutics can upregulate the expression and function of alternate checkpoints, including the T-cell protein LAG-3. Persistent interferon signaling in the TME can drive epigenetic changes in cancer cells that enable tumors to counter immune activation and disrupt tumor cell elimination. In addition, immune-suppressive macrophages can flood tumors in response to signals from dying tumor cells, further preventing effective immune responses. New clinical developments and/or approvals for therapies that target alternate immune checkpoints, such as the T-cell checkpoint LAG-3; myeloid cell proteins, such as the kinase phosphoinositide 3-kinase gamma isoform; and chronic interferon signaling, such as Jak 1 inhibitors, have been approved for cancer care or shown promise in recent clinical trials.

Targeting PI3Kγ in cancer

The phosphoinositide 3-kinases (PI3Ks) have been the focus of a significant body of cancer research since their discovery nearly 40 years ago. These lipid kinases are now known to play central roles in cancer cell proliferation, survival, migration, metabolism, and immunity and serve as the target of numerous investigational and approved therapeutics. One of these kinases, the unique class IB PI3Kγ, which is highly expressed in myeloid lineage cells and myeloid leukemias, plays prominent roles in tumor immune suppression. Inhibition of this kinase has promoted improved antitumor immune responses in recent solid tumor preclinical studies and clinical trials. New studies also identify this kinase as a driver of acute myeloid leukemia self-renewal and as a new target for the treatment of aggressive leukemias.

The Role of PI3k-Gamma Modulation in Bacterial Infection: A Review of the Literature and Selected Experimental Observations

Background: Phosphoinositide 3-kinase is a potent target for cancer therapy due to its significant role in the regulation of cellular growth and proliferation. Dysregulation of the PI3k signaling cascade can constitutively activate growth pathways to trigger the progression of cancer, resulting in the development of multiple inhibitors as cancer therapeutics. Objectives: The wide array of cells expressing PI3k also include immune cells, and the inhibition of these receptors has shown promise in combating inflammation and infectious disease, a relationship we sought to examine further. Methods: We infected wild-type and PI3kγ knockout murine macrophages as well as PI3kγ inhibitor-treated THP-1 human macrophage-like cells with Staphylococcus aureus and quantified inflammation through gene expression analysis, protein secretion assays, and immunofluorescence imaging. Results: We observed that knockout of PI3kγ in murine macrophages alongside pharmacological inhibition through IPI549 treatment in THP-1 cells led to an NF-κB-driven suppression in transcription and release of inflammatory cytokines upon infection with methicillin-resistant Staphylococcus aureus. We were also able to confirm that this suppression of NF-κB translocation and subsequent decrease in inflammatory cytokine release did not compromise and even slightly boosted the bacterial killing ability. Conclusion: PI3k is primarily targeted for cancer therapies, but further exploration can also be carried out on its potential roles in treating bacterial infection.

Progression of experimental autoimmune encephalomyelitis in mice and neutrophil-mediated blood-brain barrier dysfunction requires non-muscle myosin light chain kinase

Blood-brain barrier (BBB) dysfunction occurs in numerous central nervous system disorders. Unfortunately, a limited understanding of the mechanisms governing barrier function hinders the identification and assessment of BBB-targeted therapies. Previously, we found that non-muscle myosin light chain kinase (nmMLCK) negatively regulates the tight junction protein claudin-5 in brain microvascular endothelial cells (BMVECs) under inflammatory conditions. Here, we used complementary animal and primary cell co-culture models to further investigate nmMLCK and claudin-5 during neuroinflammation. We found that nmMLCK-knockout mice resisted experimental autoimmune encephalomyelitis (EAE), including paralysis, demyelination, neutrophil infiltration, and BBB dysfunction. However, transiently silencing claudin-5 culminated in a fulminant disease course. In parallel, we found that neutrophil-secreted factors triggered a biphasic loss in the barrier quality of wild-type BMVEC monolayers, plus pronounced neutrophil migration during the second phase. Conversely, nmMLCK-knockout monolayers resisted barrier dysfunction and neutrophil migration. Lastly, we found an inverse relationship between claudin-5 expression in BMVECs and neutrophil migration. Overall, our findings support a pathogenic role for nmMLCK in BMVECs during EAE that includes BBB dysfunction and neutrophil infiltration, reveal that claudin-5 contributes to the immune barrier properties of BMVECs, and underscore the harmful effects of claudin-5 loss during neuroinflammation.

Clonorchis sinensis infection contributes to hepatocellular carcinoma progression via enhancing angiogenesis

BACKGROUND

Clonorchis sinensis (C. sinensis) infection plays an important role in the progression of hepatocarcinogenesis. However, its specific role in HCC progression remains unclear. This study aimed to investigate whether C. sinensis contributes to angiogenesis in HCC.

METHODS

A comprehensive clinical analysis was conducted on 947 HCC patients, divided into two groups: C. sinensis (-) HCC and C. sinensis (+) HCC. Kaplan-Meier survival curves and log-rank tests were utilized to assess survival outcomes. Microvessel density (MVD) was evaluated through CD34 immunohistochemistry on hepatectomy specimens. A chemistry analyzer and blood analyzer were employed to measure the concentration of circulating angiogenesis-related biomarkers. Quantitative reverse transcription-PCR (qRT-PCR) was used to analyze the expression of angiogenesis-related genes (CD34, Ang1, Ang2, VEGF, PDGF) in HCC tissues.

RESULTS

C. sinensis infection was associated with poorer outcomes in HCC patients, with significantly shorter overall survival (OS) (p = 0.014) and recurrence-free survival (RFS) (p<0.001). Notably, C. sinensis infection led to an upregulation of MVD in HCC tissues (p = 0.041). C. sinensis (+) HCC patients exhibited significantly higher levels of circulating angiogenesis-related biomarkers, including MONO (p = 0.004), EOSO (p < 0.001), C3 (p = 0.001), FIB (p = 0.010), PLT (p = 0.003), LDH (p = 0.004), GLDH (p = 0.003), compared to C. sinensis (-) HCC patients. Moreover, qRT-PCR analysis revealed that most angiogenesis-related genes were overexpressed in patients with C. sinensis infection.

CONCLUSION

C. sinensis infection is closely associated with inflammatory responses and may promote metabolic reprogramming in HCC, thereby enhancing its malignant characteristics.

Targeting the tumour vasculature: from vessel destruction to promotion

As angiogenesis was recognized as a core hallmark of cancer growth and survival, several strategies have been implemented to target the tumour vasculature. Yet to date, attempts have rarely been so diverse, ranging from vessel growth inhibition and destruction to vessel normalization, reprogramming and vessel growth promotion. Some of these strategies, combined with standard of care, have translated into improved cancer therapies, but their successes are constrained to certain cancer types. This Review provides an overview of these vascular targeting approaches and puts them into context based on our subsequent improved understanding of the tumour vasculature as an integral part of the tumour microenvironment with which it is functionally interlinked. This new knowledge has already led to dual targeting of the vascular and immune cell compartments and sets the scene for future investigations of possible alternative approaches that consider the vascular link with other tumour microenvironment components for improved cancer therapy.

Quercetin Ameliorates Cognitive Impairment in Depression by Targeting HSP90 to Inhibit NLRP3 Inflammasome Activation

Cognitive dysfunction was a common symptom of major depressive disorder (MDD). In previous studies, psychological stress leads to activation and proliferation of microglial cells in different brain regions. Quercetin, a bioflavonoid derived from vegetables and fruits, exerts anti-inflammatory effects in various diseases. To demonstrate the role of quercetin in the hippocampal inflammatory response in depress mice. The chronic unpredictable stress (CUS) depressive mice model built is used to explore the protective effects of quercetin on depression. Neurobehavioral test, protein expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and heat shock protein 90 (HSP90), and cytokines (IL-6, IL-1β, MCP-1, and TNF-α) were assessed. Quercetin ameliorated depressive-like behavior and cognitive impairment, and quercetin attenuates neuroinflammation and by targeting HSP90 to inhibit NLRP3 inflammasome activation. Quercetin inhibited the increase of HSP90 levels in the hippocampus and reverses inflammation-induced cognitive impairment. Besides, quercetin inhibited the increased level of cytokines (IL-6, IL-1β, MCP-1, and TNF-α) in the hippocampus of the depressive model mouse and the increased level of cytokines (IL-6, IL-1β, and MCP-1) in microglia. The current study indicated that quercetin mitigated depressive-like behavior and by targeting HSP90 to inhibit NLRP3 inflammasome activation in microglia and depressive mice model, meanwhile ameliorated cognitive impairment in depression. Quercetin has huge potential for the novel pharmacological efficacy of antidepressant therapy.

Eganelisib combined with immune checkpoint inhibitor therapy and chemotherapy in frontline metastatic triple-negative breast cancer triggers macrophage reprogramming, immune activation and extracellular matrix reorganization in the tumor microenvironment

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis particularly in the metastatic setting. Treatments with anti-programmed cell death protein-1/programmed death-ligand 1 (PD-L1) immune checkpoint inhibitors (ICI) in combination with chemotherapies have demonstrated promising clinical benefit in metastatic TNBC (mTNBC) but there is still an unmet need, particularly for patients with PD-L1 negative tumors. Mechanisms of resistance to ICIs in mTNBC include the presence of immunosuppressive tumor-associated macrophages (TAMs) in the tumor microenvironment (TME). Eganelisib is a potent and selective, small molecule PI3K-γ inhibitor that was shown in preclinical studies to reshape the TME by reducing myeloid cell recruitment to tumors and reprogramming TAMs from an immune-suppressive to an immune-activating phenotype and enhancing activity of ICIs. These studies provided rationale for the clinical evaluation of eganelisib in combination with the anti-PD-L1 atezolizumab and nab-paclitaxel in firstline mTNBC in the phase 2 clinical trial MAcrophage Reprogramming in Immuno-Oncology-3 (MARIO-3, NCT03961698). We present here for the first time, in-depth translational analyses from the MARIO-3 study and supplemental data from eganelisib monotherapy Ph1/b study in solid tumors (MARIO-1, NCT02637531).

METHODS

Paired pre-treatment and post-treatment tumor biopsies were analyzed for immunophenotyping by multiplex immunofluorescence (n=11), spatial transcriptomics using GeoMx digital spatial profiling (n=12), and PD-L1 immunohistochemistry, (n=18). Peripheral blood samples were analyzed using flow cytometry and multiplex cytokine analysis.

RESULTS

Results from paired tumor biopsies from MARIO-3 revealed gene signatures of TAM reprogramming, immune activation and extracellular matrix (ECM) reorganization. Analysis of PD-L1 negative tumors revealed elevated ECM gene signatures at baseline that decreased after treatment. Gene signatures of immune activation were observed regardless of baseline PD-L1 status and occurred in patients having longer progression-free survival. Peripheral blood analyses revealed systemic immune activation.

CONCLUSIONS

This is the first report of translational analyses including paired tumor biopsies from a phase 2 clinical study of the first-in-class PI3K-γ inhibitor eganelisib in combination with atezolizumab and nab-paclitaxel in frontline mTNBC. These results support the mechanism of action of eganelisib as a TAM-reprogramming immunotherapy and support the rationale for combining eganelisib with ICI and chemotherapy in indications with TAM-driven resistance to ICI.

IL-13 and IL-17A activate β1 integrin through an NF-kB/Rho kinase/PIP5K1γ pathway to enhance force transmission in airway smooth muscle

Integrin activation resulting in enhanced adhesion to the extracellular matrix plays a key role in fundamental cellular processes. Although integrin activation has been extensively studied in circulating cells such as leukocytes and platelets, much less is known about the regulation and functional impact of integrin activation in adherent cells such as smooth muscle. Here, we show that two different asthmagenic cytokines, IL-13 and IL-17A, activate type I and IL-17 cytokine receptor families, respectively, to enhance adhesion of airway smooth muscle. These cytokines also induce activation of β1 integrins detected by the conformation-specific antibody HUTS-4. Moreover, HUTS-4 binding is increased in the smooth muscle of patients with asthma compared to nonsmokers without lung disease, suggesting a disease-relevant role for integrin activation in smooth muscle. Indeed, integrin activation induced by the β1-activating antibody TS2/16, the divalent cation manganese, or the synthetic peptide β1-CHAMP that forces an extended-open integrin conformation dramatically enhances force transmission in smooth muscle cells and airway rings even in the absence of cytokines. We demonstrate that cytokine-induced activation of β1 integrins is regulated by a common pathway of NF-κB-mediated induction of RhoA and its effector Rho kinase, which in turn stimulates PIP5K1γ-mediated synthesis of PIP2 at focal adhesions, resulting in β1 integrin activation. Taken together, these data identify a pathway by which type I and IL-17 cytokine receptor family stimulation induces functionally relevant β1 integrin activation in adherent smooth muscle and help to explain the exaggerated force transmission that characterizes chronic airway diseases such as asthma.

IL-13 and IL-17A Activate β1 Integrin through an NF-kB/Rho kinase/PIP5K1γ pathway to Enhance Force Transmission in Airway Smooth Muscle

Integrin activation resulting in enhanced adhesion to the extracellular matrix plays a key role in fundamental cellular processes. Although G-protein coupled receptor-mediated integrin activation has been extensively studied in non-adherent migratory cells such as leukocytes and platelets, much less is known about the regulation and functional impact of integrin activation in adherent stationary cells such as airway smooth muscle. Here we show that two different asthmagenic cytokines, IL-13 and IL-17A, activate type I and IL-17 cytokine receptor families respectively, to enhance adhesion of muscle to the matrix. These cytokines also induce activation of β1 integrins as detected by the conformation-specific antibody HUTS-4. Moreover, HUTS-4 binding is significantly increased in the smooth muscle of patients with asthma compared to healthy controls, suggesting a disease-relevant role for aberrant integrin activation. Indeed, we find integrin activation induced by a β1 activating antibody, the divalent cation manganese, or the synthetic peptide β1-CHAMP, dramatically enhances force transmission in collagen gels, mouse tracheal rings, and human bronchial rings even in the absence of cytokines. We further demonstrate that cytokine-induced activation of β1 integrins is regulated by a common pathway of NF-κB-mediated induction of RhoA and its effector Rho kinase, which in turn stimulates PIP5K1γ-mediated synthesis of PIP2 resulting in β1 integrin activation. Taken together, these data identify a previously unknown pathway by which type I and IL-17 cytokine receptor family stimulation induces functionally relevant β1 integrin activation in adherent smooth muscle and help explain the exaggerated force transmission that characterizes chronic airways diseases such as asthma.

Inhalable GSH-Triggered Nanoparticles to Treat Commensal Bacterial Infection in In Situ Lung Tumors

Bacterial infection has been considered one of the primary reasons for low survival rate of lung cancer patients. Herein, we demonstrated that a kind of mesoporous silica nanoparticles loaded with anticancer drug doxorubicin (DOX) and antimicrobial peptide HHC36 (AMP) (MSN@DOX-AMP) can kill both commensal bacteria and tumor cells under GSH-triggering, modulating the immunosuppressive tumor microenvironment, significantly treating commensal bacterial infection, and eliminating in situ lung tumors in a commensal model. Meanwhile, MSN@DOX-AMP encapsulated DOX and AMP highly efficiently via a combined strategy of physical adsorption and click chemistry and exhibited excellent hemocompatibility and biocompatibility. Importantly, MSN@DOX-AMP could be inhaled and accumulate in lung by a needle-free nebulization, achieving a better therapeutic effect. This system is expected to serve as a straightforward platform to treat commensal bacterial infections in tumors and promote the translation of such inhaled GSH-triggered MSN@DOX-AMP to clinical treatments of lung cancer.

Immune mechanism of low bone mineral density caused by ankylosing spondylitis based on bioinformatics and machine learning

Background and Objective: This study aims to find the key immune genes and mechanisms of low bone mineral density (LBMD) in ankylosing spondylitis (AS) patients. Methods: AS and LBMD datasets were downloaded from the GEO database, and differential expression gene analysis was performed to obtain DEGs. Immune-related genes (IRGs) were obtained from ImmPort. Overlapping DEGs and IRGs got I-DEGs. Pearson coefficients were used to calculate DEGs and IRGs correlations in the AS and LBMD datasets. Louvain community discovery was used to cluster the co-expression network to get gene modules. The module most related to the immune module was defined as the key module. Metascape was used for enrichment analysis of key modules. Further, I-DEGs with the same trend in AS and LBMD were considered key I-DEGs. Multiple machine learning methods were used to construct diagnostic models based on key I-DEGs. IID database was used to find the context of I-DEGs, especially in the skeletal system. Gene-biological process and gene-pathway networks were constructed based on key I-DEGs. In addition, immune infiltration was analyzed on the AS dataset using the CIBERSORT algorithm. Results: A total of 19 genes were identified I-DEGs, of which IFNAR1, PIK3CG, PTGER2, TNF, and CCL3 were considered the key I-DEGs. These key I-DEGs had a good relationship with the hub genes of key modules. Multiple machine learning showed that key I-DEGs, as a signature, had an excellent diagnostic performance in both AS and LBMD, and the SVM model had the highest AUC value. Key I-DEGs were closely linked through bridge genes, especially in the skeletal system. Pathway analysis showed that PIK3CG, IFNAR1, CCL3, and TNF participated in NETs formation through pathways such as the MAPK signaling pathway. Immune infiltration analysis showed neutrophils had the most significant differences between case and control groups and a good correlation with key I-DEG. Conclusion: The key I-DEGs, TNF, CCL3, PIK3CG, PTGER2, and IFNAR1, can be utilized as biomarkers to determine the risk of LBMD in AS patients. They may affect neutrophil infiltration and NETs formation to influence the bone remodeling process in AS.

Major pathways involved in macrophage polarization in cancer

Macrophages play an important role in tissue homeostasis, tissue remodeling, immune response, and progression of cancer. Consequently, macrophages exhibit significant plasticity and change their transcriptional profile and function in response to environmental, tissue, and inflammatory stimuli resulting in pro- and anti-tumor effects. Furthermore, the categorization of tissue macrophages in inflammatory situations remains difficult; however, there is an agreement that macrophages are predominantly polarized into two different subtypes with pro- and anti-inflammatory properties, the so-called M1-like and M2-like macrophages, respectively. These two macrophage classes can be considered as the extreme borders of a continuum of many intermediate subsets. On one end, M1 are pro-inflammatory macrophages that initiate an immunological response, damage tissue integrity, and dampen tumor progression by fostering robust T and natural killer (NK) cell anti-tumoral responses. On the other end, M2 are anti-inflammatory macrophages involved in tissue remodeling and tumor growth, that promote cancer cell proliferation, invasion, tumor metastasis, angiogenesis and that participate to immune suppression. These decisive roles in tumor progression occur through the secretion of cytokines, chemokines, growth factors, and matrix metalloproteases, as well as by the expression of immune checkpoint receptors in the case of M2 macrophages. Moreover, macrophage plasticity is supported by stimuli from the Tumor Microenvironment (TME) that are relayed to the nucleus through membrane receptors and signaling pathways that result in gene expression reprogramming in macrophages, thus giving rise to different macrophage polarization outcomes. In this review, we will focus on the main signaling pathways involved in macrophage polarization that are activated upon ligand-receptor recognition and in the presence of other immunomodulatory molecules in cancer.