Upregulation Of CXCR4 Research Articles

Molecular imaging of cardiac CXCR4 expression in a mouse model of acute myocardial infarction using a novel 68Ga-mCXCL12 PET tracer

BackgroundThe chemokine receptor CXCR4 and its ligand CXCL12 have been shown to be a possible imaging and therapeutic target after myocardial infarction (MI). The murine-based and mouse-specific 68Ga-mCXCL12 PET tracer could be suitable for serial in vivo quantification of cardiac CXCR4 expression in a murine model of MI. Methods and ResultsAt days 1-6 after MI, mice were intravenously injected with 68Ga-mCXCL12. Autoradiography was performed and the infarct-to-remote ratio (I/R) was determined. In vivo PET imaging with 68Ga-mCXCL12 was conducted on days 1-6 after MI and the percentage of the injected dose (%ID/g) of the tracer uptake in the infarct area was calculated. 18F-FDG-PET was performed for anatomical landmarking. Ex vivo autoradiography identified CXCR4 upregulation in the infarct region with an increasing I/R after 12 hours (1.4 ± 0.3), showing a significant increase until day 2 (4.5 ± 0.6), followed by a plateau phase (day 4) and decrease after 10 days (1.3 ± 1.0). In vivo PET imaging identified similar CXCR4 upregulation in the infarct region which peaked around day 3 post MI (9.7 ± 5.0 %ID/g) and then subsequently decreased by day 6 (2.8 ± 1.0 %ID/g). ConclusionNoninvasive molecular imaging of cardiac CXCR4 expression using a novel, murine-based, and specific 68Ga-mCXCL12 tracer is feasible both ex vivo and in vivo.

Abstract 14092: Arachidonate 5 Lipoxygenase Deficiency Drives Age-Related Obesity, Macrophage Dysfunction in Cardiac Repair, and Omnipresence of Inflammation

Introduction: Age-related inflammation is the primary hallmark of heart failure with reduced and preserved ejection fraction; however, the fundamental source of inflammation is unclear. Arachidonate 5 lipoxygenase (ALOX5) is known to direct the biosynthesis of leukotrienes and proinflammatory mediators (PIMs) that orchestrate the initiation of inflammation following myocardial infarction (MI). Hypothesis: Thus, we set out to test the role of ALOX5 to understand inflammation-resolution signaling in acute HF in aging. Methods: Male C57Bl/6J and ALOX5 -/- mice were divided into two groups: 1) young (2-4 months) and 2) aging (18 months). Mice were subjected to MI surgery that develops acute heart failure maintaining no-MI as naïve controls. Cellular and molecular mechanisms are detemined. Results: The absence of ALOX5 leads to age-related obesity with series of metabolic defects, including fatty liver. Next-gen sequencing analysis revealed that immune regulating pathways of infarcted myocardium were dysregulated in young and aging ALOX5 -/- mice compared to respective age-matched controls. In response to cardiac injury, ALOX5 -/- mice fail to initiate an inflammatory response with reduced leukotrienes B 4 and PIMs, with marked obesity-related chronic inflammation in immune defense hubs: spleen bone marrow and LV infarcted site. At the molecular level, ALOX5 deletion also reduced resolution mediators (specialized proresolving mediators; SPMs), thereby making macrophage dysfunctional with the decrease in SIRP-α. Aging superimposed on ALOX5 deficiency triggers macrophage dysfunction with the increase in proinflammatory phenotype (Ly6C hi ) and notable upregulation of CXCR4 and downregulation of resolution receptor formyl peptide receptor 2; in infarcted heart post-MI. Conclusions: Presented age-related outcome provides translational insight that ALOX5 serves as a connector for initiating PIM (turn-on) and SPMs (turn-off) essential for macrophage function and cardiac repair processes. Thus, future research is warranted to validate the role of ALOX5 in cardiometabolic defects, PIMs, and resolution mediators (SPMs) in heart failure with reduced and preserved ejection fraction.

FLT3 Inhibitors Upregulate CXCR4 and E-Selectin Ligands and CD44 Via ERK Suppression in AML Cells, and Blockade of CXCR4 and E-Selectin Signaling with GMI-1359 Overcomes AML Resistance to Quizartinib in Vitro and In Vivo

FLT3 Inhibitors Upregulate CXCR4 and E-Selectin Ligands and CD44 Via ERK Suppression in AML Cells, and Blockade of CXCR4 and E-Selectin Signaling with GMI-1359 Overcomes AML Resistance to Quizartinib in Vitro and In Vivo

NLRC5 Deficiency Deregulates Hepatic Inflammatory Response but Does Not Aggravate Carbon Tetrachloride-Induced Liver Fibrosis.

The nucleotide-binding leucine-rich repeat-containing receptor (NLR) family protein-5 (NLRC5) controls NF-κB activation and production of inflammatory cytokines in certain cell types. NLRC5 is considered a potential regulator of hepatic fibrogenic response due to its ability to inhibit hepatic stellate activation in vitro. To test whether NLRC5 is critical to control liver fibrosis, we treated wildtype and NLRC5-deficient mice with carbon tetrachloride (CCl4) and assessed pathological changes in the liver. Serum alanine transaminase levels and histopathology examination of liver sections revealed that NLRC5 deficiency did not exacerbate CCl4-induced liver damage or inflammatory cell infiltration. Sirius red staining of collagen fibers and hydroxyproline content showed comparable levels of liver fibrosis in CCl4-treated NLRC5-deficient and control mice. Myofibroblast differentiation and induction of collagen genes were similarly increased in both groups. Strikingly, the fibrotic livers of NLRC5-deficient mice showed reduced expression of matrix metalloproteinase-3 (Mmp3) and tissue inhibitor of MMPs-1 (Timp1) but not Mmp2 or Timp2. Fibrotic livers of NLRC5-deficient mice had increased expression of TNF but similar induction of TGFβ compared to wildtype mice. CCl4-treated control and NLRC5-deficient mice displayed similar upregulation of Cx3cr1, a monocyte chemoattractant receptor gene, and the Cd68 macrophage marker. However, the fibrotic livers of NLRC5-deficient mice showed increased expression of F4/80 (Adgre1), a marker of tissue-resident macrophages. NLRC5-deficient livers showed increased phosphorylation of the NF-κB subunit p65 that remained elevated following fibrosis induction. Taken together, NLRC5 deficiency deregulates hepatic inflammatory response following chemical injury but does not significantly aggravate the fibrogenic response, showing that NLRC5 is not a critical regulator of liver fibrosis pathogenesis.

Interleukin-33-Enhanced CXCR4 Signaling Circuit Mediated by Carcinoma-Associated Fibroblasts Promotes Invasiveness of Head and Neck Cancer.

Despite recent advances, treatment for head and neck squamous cell carcinoma (HNSCC) has limited efficacy in preventing tumor progression. We confirmed previously that carcinoma-associated fibroblasts (CAF)-induced interleukin-33 (IL-33) contributed to cancer progression. However, the molecular mechanisms underlying the complex communication network of the tumor microenvironment merited further evaluation. To simulate the IL-33-induced autocrine signaling, stable clones of IL-33-overexpressing HNSCC cells were established. Besides well-established IL-33/ST2 and SDF1/CXCR4 (stromal-derived factor 1/C-X-C motif chemokine receptor 4) signaling, the CAF-induced IL-33 upregulated CXCR4 via cancer cell induction of IL-33 self-production. The IL-33-enhanced-CXCR4 regulatory circuit involves SDF1/CXCR4 signaling activation and modulates tumor behavior. An in vivo study confirmed the functional role of IL-33/CXCR4 in tumor initiation and metastasis. The CXCR4 and/or IL-33 blockade reduced HNSCC cell aggressiveness, with attenuated invasions and metastases. Immunohistochemistry confirmed that IL-33 and CXCR4 expression correlated significantly with disease-free survival and IL-33-CXCR4 co-expression predicted a poor outcome. Besides paracrine signaling, the CAF-induced IL-33 reciprocally enhanced the autocrine cancer-cell self-production of IL-33 and the corresponding CXCR4 upregulation, leading to the activation of SDF1/CXCR4 signaling subsequent to cancer progression. Thus, targeting the IL-33-enhanced-CXCR4 regulatory circuit attenuates tumor aggressiveness and provides a potential therapeutic option for improving the prognosis in HNSCC patients.

Abstract 670: CXCR4 expression in tumor associated circulating cells of patients with pancreatic cancer is prognostic for progression and overall survival

Abstract Background: CXCR4 is a chemotaxis receptor implicated in the progression of Pancreatic Cancer (PC) via the activation and invasion of tumor cells. To better elucidate its role in the PC metastasis, we examined the role of CXCR4 expression on a variety of tumor associated circulating cells (TACs) [i.e. circulating tumor cells (CTCs), epithelial to mesenchymal cells (EMTs), and cancer associated macrophage-like cells (CAMLs)] as it relates to patient outcomes. A PC cell line PANC-1 was used to model the activation and expression pathway of CXCR4 in cells. Then blood samples were procured from 30 PC patients prior to the start of therapeutic intent to evaluate CXCR4 expression in TACs. CAMLs, EMTs, and CTCs were found in 93%, 63%, and 30% of PC patients respectively, with high CXCR4 expression found to significantly relate with higher TAC populations in circulation. Further, in a 2-year univariate analysis it was found that high expression of CXCR4 in CAMLs or EMTs was significantly related to both progression free survival (PFS) and overall survival (OS). These data suggest that CXCR4 expression in circulating cells in PC is strongly related to the progression and metastatic spread of the disease. Methods: PANC-1 cells were used to examine the expression and upregulation of CXCR4 by staining with an anti-CXCR4 antibody after stimulation with Isoproterenol. A prospective pilot study was initiated using anonymized peripheral blood samples from (n=30) PC patients, obtained in accordance with local IRB regulations with informed consent. TACs were isolated from the blood using a low-flow CellSieve Microfiltration system and stained for cytokeratin, CXCR4, and CD45. Wilcoxon ranked sum test and univariate analysis were used to analyze the association of CXCR4 expression on all TACs and to evaluate 24-month PFS/OS. Results: Within the PANC-1 cell line, we observed a median expression of CXCR4 intensity of roughly 210 after activation and upregulation with Isoproterenol. Within TACs in the circulation, higher numbers of CAMLs (p=0.017), EMTs (p=0.001), and CTCs (p<0.001) were all significantly related to cells with ≥210 CXCR4 expression. Further, higher expression of CXCR4 on CAMLs correlated with worse PFS (HR=4.0, 95%CI 1.5-10.5, p=0.012) and worse OS (HR=4.8, 95%CI 1.7-13.1, p=0.006), with higher CXCR4 expression in EMTs also correlated with worse PFS (HR=4.6, 95%CI 1.2-15.4, p=0.033) and worse OS (HR=5.4, 95%CI 1.5-19.2, p=0.021). Expression of CXCR4 in CTCs was not significant for PFS or OS. Conclusion: Expression of chemotaxis related receptor CXCR4 appears to have a strong relationship to higher numbers of TACs in circulation. This higher CXCR4 expression in CAMLs and EMTs also appears to correlate with rapid progression and death, indicating a relationship CXCR4 in the spread of PC and its potential use as a target for therapy. Citation Format: Kirby P. Gardner, Susan Tsai, Mohammed Aldakkak, Stephen Gironda, Cha-Mei Tang, Daniel L. Adams. CXCR4 expression in tumor associated circulating cells of patients with pancreatic cancer is prognostic for progression and overall survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 670.

18-LB: Histone Modifications and CXCR4 Chemokine Receptor Signaling in Hyperglycemic DRG Neurons

Diabetes is a global epidemic that affects many individuals throughout the world and presents a major health challenge to society. The state of chronic hyperglycemia can have many devastating secondary effects including neuropathy, nephropathy, retinopathy, and cardiovascular disease. The diabetes mediated neuropathic complications are a substantial burden to society due to a lack of therapies as well as decreased quality of life and increased mortality. Approximately 50% diabetic patients suffer from neuropathy which is described as alterations of pain sensation in the feet that leads to increased risk for infection, ulcers, non-traumatic amputations and ultimately death. Painful diabetic neuropathy (PDN) affects individuals within 20 years after the onset of disease, mediated by the gradual degeneration of axonal structures in sensory neurons. It is known that hyperglycemia is involved in the pathogenesis of this disease, but specific mechanisms are not well understood. Previous studies have shown that inflammation and epigenetic changes may play a role in the development of PDN. Specifically, it has been demonstrated that the chemokine receptor CXCR4 is involved in inflammation relating to PDN while the histone deacetylases HDAC4 and HDAC6 are involved in mediating the epigenetic changes in sensory neurons under hyperglycemic conditions. This study investigated the alterations in inflammatory mediators and epigenetic changes in sensory neurons under normal glucose and high glucose environments. Western blot and immunocytochemistry techniques were used to measure any differences in these two conditions. The results from this study demonstrated an upregulation of histone deacetylases and CXCR4 in hyperglycemic conditions, while histone acetyltransferases were shown to be down-regulated in high glucose environments. These findings may lead to potential therapeutic targets for PDN since it is a life altering condition with minimal treatment options available today. Disclosure N. Satterfield: None. V. Thakur: None. M. Chattopadhyay: None. Funding Texas Tech University Health Sciences Center El Paso (183381SEED)

Human Gastric Cancer Stem Cell (GCSC) Markers Are Prognostic Factors Correlated With Immune Infiltration of Gastric Cancer.

The prognosis of patients with gastric cancer (GC) is still unsatisfying. Numerous markers of gastric cancer stem cells (GCSCs) have been identified and were thought to be related to cancer aggressiveness. However, the roles of GCSC markers in GC patients’ prognosis and immune infiltration remain unknown. Expression of GCSC markers was analyzed using Oncomine and Gene Expression Profiling Interactive Analysis (GEPIA). Their associations with clinicopathological parameters were analyzed using UALCAN and LinkedOmics. Alternations and protein expression of GCSC markers were analyzed by cBioPortal and the Human Protein Atlas databases, respectively. The prognostic significance of GCSC markers was evaluated using Kaplan-Meier plotter. Correlations between the expression of GCSC markers and immune infiltration along with biomarkers of tumor-infiltrating immune cells (TIICs) were assessed combined Tumor Immune Estimation Resource and GEPIA. GeneMANIA was used to discover the interactive genes of GCSC markers, and enrichment analysis was performed using Database for Annotation, Visualization, and Integrated Discovery server. We identified six GCSC markers significantly up-expressed in GC, compared with normal stomach tissues. Among them, the overexpression of ICAM1, THY1, and CXCR4 significantly indicated adverse, while EPCAM indicated beneficial clinicopathological features of GC patients. The up-regulation of CXCR4 showed unfavorable prognostic significance, whereas EPCAM and TFRC showed the opposite. The six GCSC markers were all correlated with the infiltration and activation of distinct TIICs. Especially, ICAM1, THY1, and CXCR4 showed strongly positive correlations with tumor-associated macrophages. Besides, chemokine, Toll-like receptor, NF-kappa B, and HIF-1 signaling pathways might be involved in the regulation of GCSC markers on cancer development. This study proposed that GCSC markers might be promising targets of GC treatment to weaken cancer stem-like properties and strengthen anticancer immunity.

Loss of diacylglycerol kinase ε causes thrombotic microangiopathy by impairing endothelial VEGFA signaling.

Loss of function of the lipid kinase diacylglycerol kinase ε (DGKε), encoded by the gene DGKE, causes a form of atypical hemolytic uremic syndrome that is not related to abnormalities of the alternative pathway of the complement, by mechanisms that are not understood. By generating a potentially novel endothelial specific Dgke-knockout mouse, we demonstrate that loss of Dgke in the endothelium results in impaired signaling downstream of VEGFR2 due to cellular shortage of phosphatidylinositol 4,5-biphosphate. Mechanistically, we found that, in the absence of DGKε in the endothelium, Akt fails to be activated upon VEGFR2 stimulation, resulting in defective induction of the enzyme cyclooxygenase 2 and production of prostaglandin E2 (PGE2). Treating the endothelial specific Dgke-knockout mice with a stable PGE2 analog was sufficient to reverse the clinical manifestations of thrombotic microangiopathy and proteinuria, possibly by suppressing the expression of matrix metalloproteinase 2 through PGE2-dependent upregulation of the chemokine receptor CXCR4. Our study reveals a complex array of autocrine signaling events downstream of VEGFR2 that are mediated by PGE2, that control endothelial activation and thrombogenic state, and that result in abnormalities of the glomerular filtration barrier.

Profound phenotype alteration and delayed regeneration of circulating antigen presenting cells in COVID-19

Abstract Disease manifestations in COVID-19 range from mild symptoms to severe/critical illness with lung inflammation, hypercoagulation and cardiovascular complications, which may be caused by a dysregulated innate immune response. Antigen presenting cells may contribute to the inflammatory response and shape the adaptive immune response in COVID-19 patients. We therefore investigated the frequency and phenotype of circulating dendritic cells (DCs) and monocytes in hospitalized COVID-19 patients with mild/moderate or severe disease at different time points (n=65). We found an overall reduction of DCs and a shift towards the CD14+ DC3 population within the DCs in patients vs. controls. In patients with more severe disease, we observed upregulation of CXCR3, CCR2, CD40 and PD-L1, but reduced expression of CD86 and HLADR in monocytes and conventional DCs (cDCs) within the first 3 weeks after diagnosis (n=26). Increased proliferation and expansion of precursor cells in the blood indicated an enhanced turnover that was observed even in convalescent patients. Proliferating cDC2 and DC3 showed a phenotype similar to that found in healthy controls suggesting that the phenotype alterations are induced in differentiated DCs by external factors. The observed changes were accompanied by increased inflammatory cytokine levels in the plasma and lymphopenia. Thus, in more severe COVID-19 circulating cDCs and monocytes exhibited a profoundly altered expression of costimulatory molecules and were poised to exit the blood in response to inflammatory chemokines. Increased proliferation even after recovery indicated delayed regeneration of the mononuclear phagocyte system.

The Antidepressant Mirtazapine Rapidly Shifts Hepatic B Cell Populations and Functional Cytokine Signatures in the Mouse.

IntroductionB cells are important regulators of both adaptive and innate immunity. The normal liver contains significant numbers of B cells, and their numbers increase dramatically in immune-mediated liver diseases. Our previous observations suggest a hepatoprotective effect of the antidepressant mirtazapine in human and experimental immune-mediated liver disease. Therefore, we performed a series of experiments to determine the impact of mirtazapine treatment on hepatic B cell homeostasis, as reflected by B cell number, trafficking and phenotype using flow cytometry (FCM) and intravital microscopy (IVM) analysis. Mirtazapine treatment rapidly induced a significant reduction in total hepatic B cell numbers, paralleled by a compositional shift in the predominant hepatic B cell subtype from B2 to B1. This shift in hepatic B cells induced by mirtazapine treatment was associated with a striking increase in total hepatic levels of the chemokine CXCL10, and increased production of CXCL10 by hepatic macrophages and dendritic cells. Furthermore, mirtazapine treatment led to an upregulation of CXCR3, the cognate chemokine receptor for CXCL10, on hepatic B cells that remained in the liver post-mirtazapine. A significant role for CXCR3 in the hepatic retention of B cells post-mirtazapine was confirmed using CXCR3 receptor blockade. In addition, B cells remaining in the liver post-mirtazapine produced lower amounts of the proinflammatory Th1-like cytokines IFNγ, TNFα, and IL-6, and increased amounts of the Th2-like cytokine IL-4, after stimulation in vitro.ConclusionMirtazapine treatment rapidly alters hepatic B cell populations, enhancing hepatic retention of CXCR3-expressing innate-like B cells that generate a more anti-inflammatory cytokine profile. Mirtazapine-induced hepatic B cell shifts could potentially represent a novel therapeutic approach to immune-mediated liver diseases characterized by B cell driven pathology.

PDTC ameliorates neuropathic pain by inhibiting microglial activation via blockage of the TNFα-CX3CR1 pathway.

Previous studies have suggested that pyrrolidine dithiocarbamate (PDTC), a nuclear factor κB (NF-κB) inhibitor, plays a role in deterring nerve injury-induced neuropathic pain (NP). The activation of NF-κB pathway may contribute to spinal microglial activation, CX3CR1 and tumor necrosis factor-alpha (TNF-a) up-regulation. The aim of this study was to clarify whether PDTC could inhibit the development of neuropathic pain via decreasing TNF-a-induced CX3CR1 up-regulation. Sprague-Dawley rats were randomly divided into sham group and NP group. Rats in each group were treated with intrathecal infusion of PDTC (100 or 1000 pmol/d) or saline. The sciatic nerve chronic constriction injury (CCI) model was used to induce NP in rats. Mechanical stimuli and radiant heat were used to evaluate mechanical allodynia and thermal hyperalgesia. Spinal microglial marker OX42 and TNF-a were detected by immunohistochemistry. In vitro BV-2 microglia activation was induced by TNF-a incubation, and the levels of CX3CR1 were assessed by western blot and reverse transcription- polymerase chain reaction. Pain behavior and immunohistochemistry results showed that intrathecal infusion of PDTC at 100 or 1000 pmol/d prevented the development of mechanical and thermal hyperalgesia, spinal microglial activation and TNF-a expression induced by sciatic nerve CCI in rats. In vitro experiment results showed that PDTC inhibited the TNF-a-induced CX3CR1 up-regulation in BV-2 microglial cells. In conclusion, intrathecal infusion of PDTC could attenuate the pain-related behaviors induced by sciatic nerve CCI through suppressing the spinal microglia activation and TNF-a up-regulation in rats. The NF-κB activation might be responsible for TNF-a-induced CX3CR1 up-regulation in microglia.

Abstract PD15-02: Cx3cl1-cx3cr1 axis in liver metastasis of triple negative breast cancer

Abstract Triple negative breast cancer (TNBC) is a breast cancer subtype with increased risk of distant metastasis, especially to visceral organs. However, the detailed molecular mechanism underlying the visceral metastasis of TNBC is unknown. We used three patient-derived xenograft models derived from TNBC tumors with different metastatic capacities. PDX1 and PDX2 model developed distant metastasis in only lung and liver, respectively. In contrast, PDX3 tumor metastasized to both lung and liver. RNA sequencing of the primary tumor and distant metastatic sites of these three PDX models was performed. The gene expression profiles of the primary tumors of the three models showed minimally overlapping genes. However, the microenvironment gene expression profiles, measured by using the sequencing reads aligned to mouse genome, showed distinct difference between the models. Among the differentially expressed genes, we identified Cx3cr1 as a significantly upregulated gene in the liver microenvironment of the PDX models that metastasized to liver. Next, we used 4T1 syngeneic mouse mammary carcinoma model to validate the Cx3cr1 in the mouse liver tissues. Interestingly, the Cx3cr1 up-regulation occurred during the pre-metastatic period, and Cx3cl1, the ligand of the Cx3cr1, was also up-regulated in the liver tissue prior to the development of metastasis suggesting the Cx3cr1 regulates the formation of pre-metastatic niche. Cx3cl1, the ligand of the Cx3cr1, was also up-regulated in the liver tissue prior to the development of metastasis. These data suggest that Cx3cl1 and Cx3cr1-mediated tumor-microenvironment interaction is critical in developing liver metastasis in TNBC. Cx3cl1 increased the invasion and migration of Raw264.7 monocyte/macrophage cells and this effect was abrogated by the Cx3cr1 silencing in Raw264.7 cells or treating Cx3cl1 neutralizing antibody. Pathway analysis of the RNA sequencing data showed that genes involved in extracellular matrix remodeling was significantly dysregulated in the liver tissues including Lysyl Oxidase (Lox). Cx3cl1 treatment in Raw264.7 cells resulted in increased expression of Lox and MMP9 mRNA in three-dimensional culture system. The Raw264.7 cells caused increased invasion of 4T1 cells in vitro. In conclusion, our data suggest that Cx3cl1-Cx3cr1 axis plays critical role during the liver metastasis of TNBC. Citation Format: Woohang Heo, Hye-Youn Son, Ju hee Kim, Kyu Jin Lee, Myeonghee Jeon, Songbin Li, Jeehee Jang, Dong-Young Noh, Wonsik Han, Hyeong-Gon Moon. Cx3cl1-cx3cr1 axis in liver metastasis of triple negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD15-02.

Molecular imaging of inflammation crosstalk along the cardio-renal axis following acute myocardial infarction.

Rationale: Acute myocardial infarction (MI) triggers a systemic inflammatory response including crosstalk along the heart-kidney axis. We employed radionuclide-based inflammation-targeted whole-body molecular imaging to identify potential cardio-renal crosstalk after MI in a translational setup.Methods: Serial whole-body positron emission tomography (PET) with the specific CXCR4 ligand 68Ga-Pentixafor was performed after MI in mice. Tracer retention in kidneys and heart was compared to hematopoietic organs to evaluate systemic inflammation, validated by ex vivo analysis and correlated with progressive contractile dysfunction. Additionally, 96 patients underwent 68Ga-Pentixafor PET within the first week after MI, for systems-based image analysis and to determine prognostic value for adverse renal outcome.Results: In mice, transient myocardial CXCR4 upregulation occurred early after MI. Cardiac and renal PET signal directly correlated over the time course (r = 0.62, p < 0.0001), suggesting an inflammatory link between organs. Ex-vivo autoradiography (r = 0.9, p < 0.01) and CD68 immunostaining indicated signal localization to inflammatory cell content. Renal signal at 7d was inversely proportional to left ventricular ejection fraction at 6 weeks after MI (r = -0.79, p < 0.01). In patients, renal CXCR4 signal also correlated with signal from infarct (r = 0.25, p < 0.05) and remote myocardium (r = 0.39, p < 0.0001). Glomerular filtration rate (GFR) was available in 48/96 (50%) during follow-up. Worsening of renal function (GFR loss >5 mL/min/1.73m2), occurred a mean 80.5 days after MI in 16/48 (33.3%). Kaplan-Meier analysis revealed adverse renal outcome for patients with elevated remote myocardial CXCR4 signal (p < 0.05). Multivariate Cox analysis confirmed an independent predictive value (relative to baseline GFR, LVEF, infarct size; HR, 5.27).Conclusion: Systems-based CXCR4-targeted molecular imaging identifies inflammatory crosstalk along the cardio-renal axis early after MI.

The cardioprotective and anxiolytic effects of Chaihujialonggumuli granule on rats with anxiety after acute myocardial infarction is partly mediated by suppression of CXCR4/NF-κB/GSDMD pathway

AimsOver-expression of CXCR4 activates nuclear translocation of NF-κB, induces high expression of NLRP3, GSDMD, IL-1β and IL-18, which promotes severe inflammatory response following myocardial infarction. Previous studies revealed inflammation induces anxiety after myocardial infarction. The Chaihujialonggumuli granule has anti-inflammatory properties and could tranquillize mind. But the mechanism of its efficacy remains unknown. This study was to investigate the possible mechanism of BFG on cardioprotective and anxiolytic. MethodsThe expression of CXCR4, NF-κB, NLRP3and GSDMD was measured with western-blot, QRT-PCR. The expression location of CXCR4, NLRP3, GSDMD were determined by immunohistochemistry. IL-1β、IL-18 in the peripheral blood were measured by ELISA. HE staining, Masson staining and transmission electron microscopy were used to observe morphological changes of cardiomyocytes. Echocardiography was used to assess cardiac function after cardiac surgery. Elevated cross maze test and open field test were used to evaluate behaviours. Western blot was used to detect the protein expressions of 5-HT, DA, IL-1β, IL-18 and neuron damage was investigated by Nissl staining in the hippocampus. ResultsThe up-regulation of CXCR4, NF-κB, NLRP3 and GSDMD were found in the infarcted area after left coronary artery ligation. Pathological staining and analysis showed that more severe inflammatory cytokines infiltration, myocardial fibrosis, were found in myocardial tissue of the complex group rats. And when compared to the sham group, the levels of IL-1β, IL-18 was increased of the complex group in both peripheral blood and brain. Behavioural test and echocardiography indicated that the rats in complex group exploration behaviours was significantly reduced, and with poor cardiac functional recovery. The AMD3100 had an inhibitory impact of CXCR4 on the activition of its downstream effectors, alleviating inflammatory reaction. Furthermore, the BFG decreased the expression level of CXCR4, NF-κB, GSDMD, NLRP3 in the infarcted area after myocardial infarction, when compared to the complex group. The assays in the brain indicated the BFG suppressed expression and activity of IL-1β, IL-18, and improved 5-HT and DA synthesis. ConclusionsIn sum, our study indicated that BFG may reduce inflammation, treat co-existing anxiety after myocardial infarction through inhibition of CXCR4/NF-κB/GSDMD signalling.

The Integrin Adaptor Kindlin-3 Is Important for Development and Retention of Marginal Zone B Cells

The Integrin Adaptor Kindlin-3 Is Important for Development and Retention of Marginal Zone B Cells

ERK1/2 Signaling Induces Upregulation of ANGPT2 and CXCR4 to Mediate Liver Metastasis in Colon Cancer.

Carcinoma development in colorectal cancer is driven by genetic alterations in numerous signaling pathways. Alterations in the RAS-ERK1/2 pathway are associated with the shortest overall survival for patients after diagnosis of colorectal cancer metastatic disease, yet how RAS-ERK signaling regulates colorectal cancer metastasis remains unknown. In this study, we used an unbiased screening approach based on selection of highly liver metastatic colorectal cancer cells in vivo to determine genes associated with metastasis. From this, an ERK1/2-controlled metastatic gene set (EMGS) was defined. EMGS was associated with increased recurrence and reduced survival in patients with colorectal cancer tumors. Higher levels of EMGS expression were detected in the colorectal cancer subsets consensus molecular subtype (CMS)1 and CMS4. ANGPT2 and CXCR4, two genes within the EMGS, were subjected to gain-of-function and loss-of-function studies in several colorectal cancer cell lines and then tested in clinical samples. The RAS-ERK1/2 axis controlled expression of the cytokine ANGPT2 and the cytokine receptor CXCR4 in colorectal cancer cells, which facilitated development of liver but not lung metastases, suggesting that ANGPT2 and CXCR4 are important for metastatic outgrowth in the liver. CXCR4 controlled the expression of cytokines IL10 and CXCL1, providing evidence for a causal role of IL10 in supporting liver colonization. In summary, these studies demonstrate that amplification of ERK1/2 signaling in KRAS-mutated colorectal cancer cells affects the cytokine milieu of the tumors, possibly affecting tumor-stroma interactions and favoring liver metastasis formation. SIGNIFICANCE: These findings identify amplified ERK1/2 signaling in KRAS-mutated colorectal cancer cells as a driver of tumor-stroma interactions that favor formation of metastases in the liver.

Abstract PO-46: Mechanisms of resistance to the PI3K inhibitor copanlisib in marginal zone lymphoma

Abstract Background: PI3Kδ is expressed in B cells and has a central role in the B-cell receptor signaling. Copanlisib is a highly selective PI3Kδ and PI3Kα inhibitor, and it is currently under clinical development in indolent lymphomas including marginal zone lymphoma (MZL). Copanlisib is Food and Drug Administration (FDA) approved for the treatment of patients with relapsed or refractory follicular lymphoma. Nevertheless, a subset of patients can eventually relapse due to acquired resistance. A better understanding of resistance mechanisms could help to design improved therapies; hence, we generated MZL cell lines resistant to copanlisib. Materials and Methods: Cells were kept on copanlisib (IC90) until acquisition of resistance (RES) or with no drug (parental, PAR). Stable resistance was confirmed by MTT assay after 3 weeks of drug-free culture. Multidrug resistance phenotype was ruled out by confirming sensitivity to vincristine. Cells underwent transcriptome profiling (RNA-Seq) and immunophenotypic analysis. Results: The RES models were obtained from VL51 cell line with over 50-fold times higher IC50s than PAR counterparts. Of note, the copanlisib-resistant lines showed decreased sensitivity to other PI3K inhibitors such as duvelisib (50-fold) and idelalisib (5-fold) and to the BTK inhibitor ibrutinib (15-fold), suggesting that the mechanism observed here might drive resistance to other downstream B-cell receptor inhibitors. Gene expression profiles of RES showed the upregulation of cytokine signaling (IL1A, IL1B, CXCR4), NFkB (LTA, TNF), MAPK (RASGRP4, RASGRP2), and JAK-STAT (STAT3, JAK3) signaling pathways and negative regulators of apoptosis (CD44, JUN). Conversely, repressed genes in RES were involved in cell adhesion (ITGA4, ITGB1), antigen presentation (HLAs), and IFN response (PARP12, GBP6). Consistent with the overexpression of antiapoptotic signaling genes, RES cells exhibited also resistance to the BCL2-inhibitor venetoclax, either as a single as in combination with copanlisib. Flow cytometry confirmed the CXCR4 upregulation and the downregulation of CD49d (ITGA4), paired with reduced CD20 and CD81 surface expression. In accordance, addition of a CXCR4 inhibitor overcame resistance to copanlisib. Conclusions: We created a model of secondary resistance to the PI3K inhibitor copanlisib, derived from an MZL cell line. This model will help in clarifying mechanisms of resistance to the drug and to evaluate alternative therapeutic approaches. Indeed, we already identified novel potential targets, such as IL1 and CXCR4, that might be exploited in overcoming resistance to copanlisib and are worthy of further investigation. Citation Format: Alberto J. Arribas, Sara Napoli, Luciano Cascione, Eugenio Gaudio, Roberta Bordone-Pittau, Marilia Barreca, Giulio Sartori, Chiara Tarantelli, Filippo Spriano, Andrea Rinaldi, Anastasios Stathis, Georg Stussi, Davide Rossi, Emanuele Zucca, Francesco Bertoni. Mechanisms of resistance to the PI3K inhibitor copanlisib in marginal zone lymphoma [abstract]. In: Proceedings of the AACR Virtual Meeting: Advances in Malignant Lymphoma; 2020 Aug 17-19. Philadelphia (PA): AACR; Blood Cancer Discov 2020;1(3_Suppl):Abstract nr PO-46.

Prometastatic CXCR4 and Histone Methyltransferase EZH2 are Upregulated in SMARCB1/INI1-deficient and TP53-mutated Metastatic Poorly Differentiated Chordoma to the Liver

Abstract Introduction/Objective Chordoma is a rare tumor most commonly arising in the sacrococcygeal region from notochord remnants. Usually, these tumors are locally invasive and recurrent, but do not have the capability to metastasize. A newly described aggressive variant called poorly differentiated chordoma is different than conventional chordoma in that it does not have the well-differentiated histologic appearance of conventional chordoma and also exhibits loss of SMARCB1/INI1. Methods Herein, we describe a case of poorly differentiated chordoma with SMARCB1/INI1 loss, concurrent TP53 mutation and Rb1 loss. Results The patient is a 55-year-old man with a history of a previously resected sacrococcygeal chordoma, who was found to have new hepatic, lung, and adrenal lesions. Biopsy of the liver showed sheets of malignant epithelioid cells with vacuolated cytoplasm, areas of necrosis, and up to 5 mitoses in one high power field. No physaliferous features or matrix material were seen. After an extensive panel of immunohistochemical markers, the origin of the metastatic tumor could not be determined and the tumor was only positive for Cam5.2, EMA, and CD56. Brachyury was performed due to the patient’s previous history and was positive. Genomic testing showed a SMARCB1 mutation, a TP53 mutation, and RB1 loss. Additional markers were performed and the tumor showed a Ki-67 proliferation index of approximately 80%, mutant p53 protein, loss of INI1, and strong expression of prometastatic CXCR4 and the histone methyltransferase EZH2. The most recent follow-up of the patient showed that the patient was receiving palliative care. Conclusion Poorly differentiated chordoma is a highly aggressive variant of chordoma with few cases reported. This case of SMARCB1/INI-deficient, poorly differentiated chordoma also showed concurrent TP53 mutation and loss of RB1, which resulted in malignant transformation with loss of differentiation, cell cycle progression, up-regulation of prometastatic CXCR4 and the histone methyltransferase EZH2 causing aggressive behavior and metastasis.

Genetic and Non-Genetic Mechanisms of Resistance to BCR Signaling Inhibitors in B Cell Malignancies.

The approval of BTK and PI3K inhibitors (ibrutinib, idelalisib) represents a revolution in the therapy of B cell malignancies such as chronic lymphocytic leukemia (CLL), mantle-cell lymphoma (MCL), diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), or Waldenström’s macroglobulinemia (WM). However, these “BCR inhibitors” function by interfering with B cell pathophysiology in a more complex way than anticipated, and resistance develops through multiple mechanisms. In ibrutinib treated patients, the most commonly described resistance-mechanism is a mutation in BTK itself, which prevents the covalent binding of ibrutinib, or a mutation in PLCG2, which acts to bypass the dependency on BTK at the BCR signalosome. However, additional genetic aberrations leading to resistance are being described (such as mutations in the CARD11, CCND1, BIRC3, TRAF2, TRAF3, TNFAIP3, loss of chromosomal region 6q or 8p, a gain of Toll-like receptor (TLR)/MYD88 signaling or gain of 2p chromosomal region). Furthermore, relative resistance to BTK inhibitors can be caused by non-genetic adaptive mechanisms leading to compensatory pro-survival pathway activation. For instance, PI3K/mTOR/Akt, NFkB and MAPK activation, BCL2, MYC, and XPO1 upregulation or PTEN downregulation lead to B cell survival despite BTK inhibition. Resistance could also arise from activating microenvironmental pathways such as chemokine or integrin signaling via CXCR4 or VLA4 upregulation, respectively. Defining these compensatory pro-survival mechanisms can help to develop novel therapeutic combinations of BTK inhibitors with other inhibitors (such as BH3-mimetic venetoclax, XPO1 inhibitor selinexor, mTOR, or MEK inhibitors). The mechanisms of resistance to PI3K inhibitors remain relatively unclear, but some studies point to MAPK signaling upregulation via both genetic and non-genetic changes, which could be co-targeted therapeutically. Alternatively, drugs mimicking the BTK/PI3K inhibition effect can be used to prevent adhesion and/or malignant B cell migration (chemokine and integrin inhibitors) or to block the pro-proliferative T cell signals in the microenvironment (such as IL4/STAT signaling inhibitors). Here we review the genetic and non-genetic mechanisms of resistance and adaptation to the first generation of BTK and PI3K inhibitors (ibrutinib and idelalisib, respectively), and discuss possible combinatorial therapeutic strategies to overcome resistance or to increase clinical efficacy.