High CXCR4 Research Articles

In Vivo Detection of Lymph Nodes Metastasis of ESCC Using CXCR4-Targeted Tracer [64Cu]Cu-NOTA-CP01.

Esophageal squamous cell carcinoma (ESCC) frequently exhibits skip metastasis to lymph nodes; however, non-invasive imaging techniques capable of directly visualizing metastatic lymph nodes (MLN) are still lacking. Although biopsy is the clinical standard method, it is invasive and poses risks to patient health. This study aims to detect MLN in an intralymphatic tumor metastasis model of ESCC using the CXCR4-targeted tracer [64Cu]Cu-NOTA-CP01. The CXCR4 expression in ESCC cell lines was assessed using Western blot and immunofluorescence. An intralymphatic tumor metastasis model was established and monitored using bioluminescence imaging (BLI). Small animal PET studies and biodistribution studies were performed to evaluate the specificity of [64Cu]Cu-NOTA-CP01 for MLN. Histopathology evaluation was employed to check for the presence of metastatic tumor cells and to assess CXCR4 expression levels in the metastatic lymph nodes. The intralymphatic tumor metastasis model was successfully established using the EC109/Luc cell line, which exhibited high CXCR4 expression, as verified by BLI. PET/CT imaging showed that the MLN uptakes in the baseline group were significantly inhibited in the blocking group. The ratios of MLN/muscle and MLN/blood werealso significantly higher in the baseline group than in the blocking group. Ex vivo PET/CT imaging of MLN corroborated the in vivo data. Biodistribution studies further supported the PET imaging studies, showing rapid clearance of the tracer from the blood and major organs, with significantly higher MLN/muscle and MLN/blood ratios in the baseline group compared to the blocking group. Histopathological staining verified positive CXCR4 expression in these lymph nodes containing metastatic tumor cells. Targeting CXCR4 with [64Cu]Cu-NOTA-CP01 for PET imaging of lymph nodes metastasis represents a promising approach that warrants further investigation. These findings have the potential to enhance diagnostic and therapeutic strategies for individuals with lymph nodes metastasis of ESCC.

Induced collagen type-I secretion by hepatocytes of the melanoma liver metastasis is associated with a reduction in tumour-infiltrating lymphocytes.

Overall patients with melanoma liver metastasis (MLiM) have a dismal prognosis and poor responses to the standard of care treatment. Understanding the role of the tumour microenvironment (TME) is critical for discovering better strategies to overcome intrinsic therapy resistance in MLiM. The aim was to understand the crosstalk signalling pathways between hepatocytes and metastatic melanoma cells in the TME of MLiM. Hepatocytes and melanoma tumour cells of MLiM were assessed using transcriptomic NanoString GeoMx digital spatial profiling (NGDSP) assay. Functional assays were performed using normal hepatocytes and MLiM-derived cell lines. Validation was performed using multiplex immunofluorescence. In NGDSP analysis adjacent normal hepatocytes (ANH) had higher CXCR4 and COL1A1/2 levels than distant normal hepatocytes (DNH), while melanoma cells had higher TNF-α levels. In vitro, MLiM cell lines released TNF-α which upregulated CXCR4 and CXCL12 levels in ANH. CXCL12 activated CXCR4, which triggered AKT and NFκB signalling pathways. Consequently, AKT signalling induced the upregulation of collagen type I. MLiM were significantly encircled by a shield of collagen, whereas other liver metastases showed reduced levels of collagen. Of all the liver metastasis analyzed, the presence of collagen in melanoma liver metastasis was associated with a reduction in tumour-infiltrating lymphocytes. MLiM modified ANH to increase collagen production and created a physical barrier. The collagen barrier was associated with a reduction of immune cell infiltration which could potentially deter MLiM immune surveillance and treatment responses. Spatial analyses of melanoma liver metastasis show that adjacent normal hepatocytes have increased collagen-type I levels. Melanoma liver metastases tumour cells secrete enhanced levels of TNF-α to stimulate CXCR4/CXCL12 upregulation in adjacent normal hepatocytes. Activation of CXCR4 promotes AKT and NF-κB signalling pathways to promote collagen-type I secretion in adjacent normal hepatocytes. Elevated collagen levels were associated with reduced tumour-infiltrating lymphocytes.

Developmental trajectory of unconventional T cells of the cynomolgus macaque thymus

As nonhuman primates are immunologically the closest model to humans, a comprehensive understanding of T-cell development in these species is crucial. However, the differentiation pathways in which thymocytes participate, along with their heterogeneity, remain poorly characterized. Using single-cell RNA sequencing, we thoroughly profiled the development of various T-cell lineages in the juvenile cynomolgus monkey thymus, identifying and characterizing 12 distinct thymic cell states or types. Interestingly, we identified two unexpected cell types, an agonist-selected and a memory-like cell population. The agonist-selected cell population expressed genes associated with strong TCR signaling, such as PDCD1, CD5, NFKBID, NFATC1, BCL2L11, and NR4A1 but exhibiting significantly higher PDCD1 expression compared with cells following the conventional developmental pathway. Additionally, we identified a substantial number of memory-like cell populations characterized by high CXCR3 and EOMES expression. Notably, this population also highly expressed the effector-associated markers, GZMK, NKG7, and GNLY, as well as the innate cell-associated markers, ZBTB16, TYROBP, KLRB1, KLRC1, and NCR3. The EOMES + memory-like cell population expressed highly PDCD1, indicating the presence of an agonist-selection footprint. Our findings provide insights into the agonist-selection pathway that allows self-reactive thymocytes to survive thymic selections and differentiate into various unconventional T-cell lineages.

Prognostic value of T regulatory cells and immune checkpoints expression in tumor-draining lymph nodes for oral squamous cell carcinoma.

Forty-nine OSCC patients were enrolled. One TDLN per patient was analysed using flow cytometry to profile immune-checkpoint expression (PD-1, CTLA-4, TIGIT, TIM-3, LAG-3) and other markers such as CD69, CXCR5 on CD4+, CD8+, and Tregs. Disease-free survival (DFS) and overall survival (OS) were assessed. According to multivariate analysis, elevated levels of FoxP3+CD4+ and TIGIT+CD8+ cells in TDLNs correlated with significantly worse DFS, while high CXCR5+CD4+ levels were associated with better DFS. Notably, the expression of immune checkpoints on T cells within TDLNs showed significant associations with recurrence status. Patients experiencing recurrence exhibited heightened levels of T regulatory cells, CD4+PD-1+ and CD4+CTLA-4+, cells in TDLNs. Survival multivariate analyses revealed that T status emerged as an independent predictor of OS. The findings highlight the critical role of TDLNs in the immune microenvironment of OSCC and establish immune checkpoint expression on T cells as promising prognostic biomarkers. These insights upgrade the prognostic framework for OSCC and pave the way for individualized therapeutic strategies. The prognostic significance of TDLNs and a high expression of immune checkpoint inhibitors is a compelling argument for the adoption of neoadjuvant immunotherapy.

CXCR4 orchestrates the TOX-programmed exhausted phenotype of CD8+ T cells via JAK2/STAT3 pathway

Evidence from clinical trials suggests that CXCR4 antagonists enhance immunotherapy effectiveness in several cancers. However, the specific mechanisms through which CXCR4 contributes to immune cell phenotypes are not fully understood. Here, we employed single-cell transcriptomic analysis and identified CXCR4 as a marker gene in Tcells, with CD8+PD-1high exhausted T (Tex) cells exhibiting high CXCR4 expression. By blocking CXCR4, the Tex phenotype was attenuated invivo. Mechanistically, CXCR4-blocking Tcells mitigated the Tex phenotype by regulating the JAK2-STAT3 pathway. Single-cell RNA/TCR/ATAC-seq confirmed that Cxcr4-deficient CD8+ Tcells epigenetically mitigated the transition from functional to exhausted phenotypes. Notably, clinical sample analysis revealed that CXCR4+CD8+ Tcells showed higher expression in patients with a non-complete pathological response. Collectively, these findings demonstrate the mechanism by which CXCR4 orchestrates CD8+ Tex cells and provide a rationale for combining CXCR4 antagonists with immunotherapy in clinical trials.

IS4-FAM, a fluorescent tool to study CXCR4 affinity and competitive antagonism in native cancer cells.

The ability to accurately measure drug-target interaction is critical for the discovery of new therapeutics. Classical pharmacological bioassays such as radioligand or fluorescent ligand binding assays can define the affinity or Kd of a ligand for a receptor with the lower the Kd, the stronger the binding and the higher the affinity. However, in many drug discovery laboratories today, the target of interest if often artificially upregulated by means of transfection to modify the host cell's genetic makeup. This then potentially invalidates the assumptions of classical pharmacology affinity calculations as the receptor of interest is no longer at normal physiological densities. The CXCR4 receptor is expressed on many different cancer cell types and is associated with metastasis and poor prognosis. Therefore, the CXCR4 receptor is a desirable target for novel therapeutics. In this study, we explore the applicability of the newly developed fluorescently tagged CXCR4 antagonists, IS4-FAM as an investigative tool to study CXCR4 affinity and competitive antagonism in native, non-transfected cancer cells using confocal microscopy and flow cytometry. IS4-FAM directly labels CXCR4 in several cell lines including high CXCR4 expressing SK-MEL-28 (malignant melanoma) and PC3 (metastatic prostate cancer) and lower CXCR4 expressing THP-1 (acute monocytic leukemia) and was competitive with the established CXCR4 antagonist, AMD3100. This highlights the potential of IS4-FAM as a pharmacological tool for drug discovery in native cells lines and tissues.

Glycolysis-related genes predict prognosis and indicate immune microenvironment features in gastric cancer.

Gastric cancer (GC) is a major contributor to cancer-related mortality. Glycolysis plays a pivotal role in tumor microenvironment (TME) reprogramming. In this research, the functions of glycolysis-associated genes (GRGs) were evaluated to predict the outcome and reveal the characteristics of the immune microenvironment in individuals with stomach cancer. The Cancer Genome Atlas (TCGA)-stomach adenocarcinoma (STAD) cohort provided gene expression and clinical data for gastric cancer (GC) patients, which were further authenticated using datasets sourced from the Gene Expression Omnibus (GEO). By referencing the Molecular Signatures Database (MSigDB), a total of 326 GRGs were pinpointed. The various subtypes of GC were outlined through consensus clustering, derived from the expression patterns of these GRGs. Utilizing multivariate Cox regression analysis, a multigene risk score model was formulated. Both the CIBERSORT and ESTIMATE algorithms played a pivotal role in assessing the immune microenvironment. To delve into the biological functions of the key genes, wound healing, transwell invasion, and MTT assays were conducted. Based on the expression patterns of GRGs, patients were categorized into two distinct groups: the metabolic subtype, designated as cluster A, and the immune subtype, labeled as cluster B. Patients belonging to cluster B exhibited a poorer prognosis. A prognostic risk score model, formulated upon the expression levels of six key GRGs - ME1, PLOD2, NUP50, CXCR4, SLC35A3, and SRD35A3 - emerged as a viable tool for predicting patient outcomes. The downregulation of CXCR4 notably diminished the glycolytic capacity of gastric cancer (GC) cells, alongside their migratory, invasive, and proliferative capabilities. Intriguingly, despite the adverse prognostic implications associated with both the immune subtype (cluster B) and the high-risk cohort, these groups exhibited a favorable immune microenvironment coupled with elevated expression of immune checkpoint genes. Our investigations revealed a positive correlation between high CXCR4 expression and low ME1 expression with the infiltration of CD8+ T cells, as well as an enhanced responsiveness to treatment with an anti-PD-1 immune checkpoint inhibitor. In this study, we discovered that the expression profiles of GRGs hold the potential to forecast the prognosis of gastric cancer (GC) patients, thereby possibly aiding in clinical treatment decision-making.

New Emerging Chemokine Receptors: CCR5 or CXCR5 on Tumor Is Associated with Poor Response to Chemotherapy and Poor Prognosis in Locally Advanced Triple-Negative Breast Cancer.

We aim to investigate any possible associations between chemokine receptor expression and responses to neoadjuvant chemotherapy (NAC) along with outcomes in patients with triple-negative breast cancer (TNBC) with locally advanced disease. Expressions of chemokine receptors were examined immunohistochemically after staining archival tissue of surgical specimens (n = 63) using specific antibodies for CCR5, CCR7, CXCR4, and CXCR5. Patients with high CCR5, CCR7, CXCR4, and CXCR5 expression on tumors and high CXCR4 expression on tumor-infiltrating lymphocytes (TILs) were less likely to have a pathological complete response (pCR) or Class 0-I RCB-Index compared to others. Patients with residual lymph node metastases (ypN-positive), high CCR5TM(tumor), and high CXCR4TM expressions had an increased hazard ratio (HR) compared to others (DFS: HR = 2.655 [1.029-6.852]; DSS: HR = 2.763 [1.008-7.574]), (DFS: HR = 2.036 [0.805-5.148]; DSS: HR = 2.689 [1.020-7.090]), and (DFS: HR = 2.908 [1.080-7.829]; DSS: HR = 2.132 (0.778-5.846)), respectively. However, patients without CXCR5TIL expression had an increased HR compared to those with CXCR5TIL (DFS: 2.838 [1.266-6.362]; DSS: 4.211 [1.770-10.016]). High expression of CXCR4TM and CCR5TM was found to be associated with poor prognosis, and CXCR5TM was associated with poor chemotherapy response in the present cohort with locally advanced TNBC. Our results suggest that patients with TNBC could benefit from a chemokine receptor inhibitor therapy containing neoadjuvant chemotherapy protocols.

Abstract 2660: CXCL9/10 is critical for immunotherapeutic efficacy by recruiting and activating T lymphocytes in tumor microenvironment

Abstract Background: Tumor immunotherapies targeting PD-(L)1 exhibit anti-tumor efficacy in only about 20% of patients with a variety of cancers. Literature has demonstrated that “hot tumor” which contains high T lymphocytes in tumor microenvironment exhibits a better response to immunotherapies than “cold tumor”. Therefore, we hypothesize that T lymphocyte-recruited factors play the roles determining the immunotherapeutic efficacy, including CXCL9, 10, and 11, which are located in human chromosome 4 with consistent co-expression and protein structure. Aims: The aim of this study is to investigate whether CXCL9/10 is critical in determining the anti-PD-(L)1 immunotherapeutic efficacy. Methods: GEPIA, cBioPortal, and Kaplan-Meier Plotter were used to investigate the gene expression, co-expression, and immunotherapeutic association for CD274 (PD-L1), ICAM1, and CXCL9/10 in lung, colon, and liver cancers. qPCR and flow cytometry were used to detect the gene expression in tumor cells and T lymphocytes, particularly comparing the differences between LL/2 and CT26 cells whereas LL/2 is immunotherapy-resistant and CT26 is immunotherapy-sensitive. CD8+ T cell transwell assay and qPCR were used to measure the function of CXCL10 on CD8+ T cell migration and activation, whereas IFNγ and IL-2 as the activation markers. Results: We found that CXCL9/10 overexpressed in a variety of tumors, including lung, colon, and liver tumors with a correlation with PD-L1. However, PD-L1 was not overexpressed in most tumors. High PD-L1 and CXCL10 are basically associated with better survival rates in tumor patients receiving immunotherapies. Correlation analysis revealed that IRF-1 and STAT1 were correlated with PD-L1 and CXCL10 expression in lung cancer. Since literature has indicated that LL/2-derived syngeneic tumor exhibits immunotherapy-resistant and CT26 exhibits immunotherapy-sensitive, we further compared the gene expression between them. We found that IFNA, IFNG, CXCL10, and PD-L1 all expressed higher levels in CT26 cells than LL/2. Moreover, we found that T lymphocytes specifically expressed high CXCR3, a receptor of CXCL9/10, including CD4+ T and CD8+ T cells by flow cytometry. As expected, CD8+ T cells can be recruited in a transwell assay by IFNα and CXCL9. In addition, we found that IFNα induced CXCL10 expression in monocytes and CXCL10 increased activation markers IFNγ and IL-2 in CD4+ T and CD8+ T cells. Conclusions: This study revealed that CXCL9/10 expression is correlated with PD-L1 in tumors, resulting in better immunotherapeutic efficacy. The evidence demonstrated that CT26 intrinsically exhibited higher IFNs and CXCL9/10 compared to LL/2. Therefore, CXCL9/10 potentially recruits and activates CD8+ T cells to tumor microenvironment, transferring “cold tumor” to “hot tumor”. This study indicates that CXCL9/10 is critical for immunotherapeutic efficacy. Citation Format: Chun-Chia Cheng, Jungshan Chang, Zong-Lin Sie, Ai-Sheng Ho, Cheng-Liang Peng, Chun-Chao Chang. CXCL9/10 is critical for immunotherapeutic efficacy by recruiting and activating T lymphocytes in tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2660.

Comparison of the CXCR5-Antibody Drug Conjugate (ADC; VIP924) to a CD19-ADC and a CD79b-ADC in a Humanized Rec-1 Mantle Cell Lymphoma (MCL) Mouse Model

Introduction The chemokine receptor CXCR5 is highly expressed in MCL, which is a rare subtype of non-Hodgkin lymphoma. VIP924 is a first-in-class CXCR5-targeting ADC composed of a legumain-cleavable linker and a kinesin spindle protein inhibitor (KSPi) payload. We compared VIP924 with a CD19- and a CD79b- targeting ADC in a humanized mouse model of MCL. Methods Expression of CXCR5 and the B-cell targets CD19 and CD79b were analyzed on tumor samples from patients with MCL using immunohistochemistry. Slides were examined by a pathologist and scored for expression. NSG-SGM3 mice were transplanted with human hematopoietic stem cells from 4 different donors and after engraftment transplanted subcutaneously with REC-1 MCL cells into their flanks. When subcutaneous tumors reached a size of 100 mm 3, mice were randomized into 5 groups and treated with 10 mg/kg of an isotype control ADC, 3 mg/kg polatuzumab vedotin, 0.66 mg/kg loncastuximab teserine, 3 mg/kg VIP924, or 10 mg/kg VIP924 every 5 days for 4 doses. Immunophenotyping of peripheral blood was performed by flow cytometry before starting treatment (Day 0) and on Day 5 and Day 18 during the treatment. At the end of the experiment, immunophenotyping was also done on tumors, spleen, and bone marrow. Complete blood count was analyzed based on single cell evaluation (Drew Scientific HemaVet 950FS Auto Blood Analyzer). Results By immunohistochemistry CXCR5 and CD19 showed comparable high expression on patient samples, whereas CD79b expression was moderate. Treatment of humanized mice bearing REC-1 tumors with VIP924 at 10 mg/kg reduced tumor growth effectively (p<0.0001 vs. isotype control on Day 10), while treatment with polatuzumab vedotin and loncastuximab teserine showed no effects on tumor growth. This outcome was also reflected in the median survival rates for the different groups with 17 days for isotype control and polatuzumab vedotin, 14 days for loncastuximab teserine and not reached for the 10-mg/kg VIP924 group. However, polatuzumab vedotin treatment significantly reduced hCD45+ cells in peripheral blood and spleen, while loncastuximab teserine treatment showed a clear trend for reduction. VIP924 treatment in both arms had no effect on peripheral or splenic hCD45+ cells. All tested ADCs reduced the CD19+ and more mature CD19+/CXCR5+ B-cells in peripheral blood and spleen, with polatuzumab vedotin and loncastuximab teserine showing significant (p<0.0001 vs. isotype control on Day 18) effects on CD19+ cell reductions, while VIP924 treatment showed a milder reduction in CD19+ cells (p= 0.0051 for 3 mg/kg and p= 0.0407 for 10 mg/kg VIP924). Loncastuximab teserine treatment increased the amount of myeloid derived suppressor cells in the peripheral blood significantly (p= 0.0467). In contrast, VIP924 led to a significant (p< 0.0001) increase in peripheral regulatory T-cells compared with isotype control. Complete blood counts from treated mice showed a reduction of white blood cells (WBC), absolute lymphocyte count, and absolute monocyte count in loncastuximab teserine-treated animals. Loncastuximab teserine treatment also reduced red blood cell count and hemoglobin values. In VIP924-treated animals, no effects on WBC, red blood cell count, or hemoglobin values were observed. All treatments showed no detrimental effects on body weights of the mice. Conclusion CXCR5 is a highly attractive target in B-cell malignancies such as diffuse large B-cell lymphoma and MCL due to high CXCR5 surface expression. VIP924, a CXCR5-targeting ADC, showed high potency and superiority to other B-cell-targeted ADCs in a humanized mouse model of MCL. In this MCL model in humanized mice, VIP924 at 10 mg/kg treatment showed a significant reduction in tumor growth and improvement in survival, while polatuzumab vedotin and loncastuximab teserine had no effect on tumor growth or survival. Interestingly, VIP924 was the only ADC to cause a significant increase in peripheral T regulatory cells, which may enhance tumor growth inhibition. Loncastuximab teserine had a deleterious effect on several hematologic parameters, which was not observed with VIP924 or polatuzumab vedotin. The efficacy and tolerability observed in this study with VIP924 suggests further testing in human clinical trials is warranted.

Use of Combination Premedication Prior to Motixafortide Administration Reduced Severity and Frequency of AEs in the Phase 3 Genesis Trial - a Single Center Analysis

Background: Motixafortide is a novel, high affinity CXCR4 antagonist with extended receptor occupancy that facilitates the migration of hematopoietic stem and progenitor cells from the bone marrow into the peripheral blood in preparation for autologous stem cell transplantation (ASCT). In prior pre-clinical and clinical studies, motixafortide was associated with transient hypersensitivity and injection site reactions. Strategies to mitigate such adverse events (AEs) commonly include agents with antihistamine activity. The Phase 3 GENESIS trial demonstrated that 88.8% of Multiple Myeloma patients mobilized ≥6x10 6 CD34+ cells/kg (local labs) in 1 leukapheresis procedure (LP) following the administration of 1 dose of motixafortide in combination with GCSF. Per initial protocol, premedication with an antihistamine H1 blocker prior to motixafortide administration was provided to all patients. However, during the course of the GENESIS study a protocol amendment was implemented to include premedication with an antihistamine H1 blocker, an H2 blocker, a leukotriene inhibitor and acetaminophen prior to motixafortide administration. Here we report the safety findings in a cohort of patients at who received single drug premedication with an H1 antihistamine prior to the protocol amendment and those who received the updated combination pre-medication regimen following protocol amendment. Methods:The GENESIS trial was a multicenter, randomized, double-blind, placebo-controlled study in 122 transplant-eligible multiple myeloma patients, as previously described (PMID: 37069359). Included in this analysis are 46 patients enrolled at the Washington University in St. Louis; 32 patients were randomized to the motixafortide treatment arm and 14 patients were randomized to the placebo arm. Among motixafortide-treated patients, 22 received a single-agent H1 blocker pre-medication and 10 received a combination pre-medication regimen comprising of an H1 blocker, an H2 blocker, a leukotriene inhibitor and acetaminophen. All pre-medications were administered within 1 hour prior to motixafortide administration. Hypersensitivity AEs included all events coded to the MedDRA terms of urticaria, pruritus, flushing, erythema, rash, hypersensitivity or anaphylaxis. Injection site reactions included all events coded to the MedDRA High Level Term of Injection Site Reaction. All AEs were graded using CTCAE criteria and were recorded up to 30 days from the last dose of motixafortide. Results: Overall, motixafortide was safe and well tolerated with no episodes of anaphylaxis, no Grade 4 AEs and no deaths. The most commonly observed AEs included transient hypersensitivity and injection site reactions. The frequency of motixafortide-associated hypersensitivity AEs of any grade was reduced from 90.9% with single-agent H1 blocker pre-medication to 20% with the combination pre-medication regimen, similar to the 20-25% rate of hypersensitivity AEs reported in the placebo + GCSF cohort (Table 1). In addition, all hypersensitivity AEs that occurred following combination pre-medication were graded mild in severity (Figure 1). Meanwhile the frequency of injection site AEs of any grade was reduced from 95.5% with single-agent H1 blocker pre-medication to 80.0% with the combination pre-medication regimen (Table 1). Furthermore, a notable improvement in severity of injection site AEs was observed, with moderate-severe injection site AEs reduced from 27% with single-agent H1 blocker pre-medication to 0% with the combination pre-medication regimen (Figure 1). Conclusions:Motixafortide was safe and well tolerated with no episodes of anaphylaxis, no Grade 4 AEs and no deaths. Following implementation of a protocol amendment using combination pre-medication with an antihistamine H1 blocker, an H2 blocker, a leukotriene inhibitor and acetaminophen, the frequency and severity of hypersensitivity and injection site AEs associated with motixafortide were markedly improved.

Prolonged CXCR4 Receptor Occupancy By Motixafortide Following a Single Subcutaneous Injection Is Associated with Extended Mobilization of CD34+ Cells in Peripheral Blood for > 24 Hours

Background: Interaction between CXCL12 (SDF-1) and its receptor, CXCR4, plays a critical role in the retention of CD34+ hematopoietic stem and progenitor cells (HSPCs) in the bone marrow. Motixafortide (motix) is a novel selective CXCR4 antagonist with high affinity for CXCR4 (IC 50 0.42 - 4.5nM), slow dissociation (Kd = 3.38e-5 s-1), and high plasma protein binding (>99%). In the Phase 3 GENESIS trial (NCT03246529), motix added to G-CSF (G) resulted in significantly higher mobilization of HSPCs in patients with multiple myeloma (MM) prior to autologous stem cell transplantation, with 88.8% of patients collecting ≥6x10 6 CD34+ cells/kg (local lab) in 1 leukapheresis procedure (LP) 10-14 hours following a single dose of motix (1.25mg/kg). Of note, GENESIS trial patients requiring additional LPs to meet HSPC mobilization goals underwent a second LP at 34-38 hours post-motix, with a total of 92.5% of patients meeting their collection goal. Here, we report in-vitro receptor occupancy, as well as clinical pharmacokinetics (PK) and pharmacodynamics (PD) of peripheral blood (PB) mobilization of CD34+ cells/ μL in healthy volunteers (HV) and patients with MM following motix administration. Methods: CXCR4 receptor occupancy and dissociation rate were assessed by incubating increasing doses of motix (3-500nM) with Jurkat cells in vitro followed by washing and incubation 0-72 hours later with either an anti-CXCR4 12G5 fluorophore-conjugated monoclonal antibody (mAb) (competes with motix for binding to CXCR4) or an anti-CXCR4 1D9 fluorophore-conjugated mAb (binds to CXCR4 but does not compete with motix) followed by flow cytometry. In HV (NCT05293171), PB samples were collected following a single subcutaneous (SC) administration of motix (1.25mg/kg). PK timepoints were pre-dose and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, and 24 hours post-motix; and PD timepoints were pre-dose and at 0.75, 2, 4, 8, 12, 16, and 24 hours post-motix. In patients with MM, PB samples were collected following SC motix (1.25mg/kg) added to G. PK timepoints were pre-motix (post-G) and 0.25, 0.5, 1, 2, 4, 8, and 12 hours post- motix; and PD timepoints were pre-motix (post-G) and 12 hours post-motix. Results: In vitro studies demonstrated complete CXCR4 receptor occupancy at 3 nM (6.48 ng/mL) of motix, with increasing concentrations resulting in longer receptor occupancy of >72 hours. Due to high protein binding, a minimum total plasma concentration of 800 ng/mL is required to achieve a free fraction of 3nM. This level was achieved following administration with doses ≥ 1.0 mg/kg (Fig 1A). PK analysis in HVs and in patients with MM dosed with 1.25 mg/kg demonstrated that motix was rapidly absorbed (maximum concentration within 0.25-1 hours). Mean maximal plasma concentrations were 2245 ± 791 ng/mL (1040nM) in HVs and 1800 ± 695 ng/mL (834nM) in patients with MM. Notably, the half-life of motix was 1-3 hours. However, despite the short half-life, the high CXCR4 receptor affinity and slow dissociation rate of motix led to an extended PD effect. In HVs who received motix as monotherapy, median PB CD34+ counts increased from baseline of 1.6 CD34+ cells/µl to 17 CD34+ cells/ μL within 4 hours post-motix, reached maximal levels of 43 CD34+ cells/μL at 16 hours post-motix and remained elevated at 36 CD34+ cells/μL at the last observation time point 24 hours post-motix (Fig 1B). In MM patients who received motixafortide after 4 doses of G-CSF, there was a 6.6 fold increase in median PB CD34+ cell counts, from 15.8 cells/μL (post-G-CSF, pre-motix) to 116.0 CD34+ cells/μL at 12 hours post-motix (Fig 1B). Conclusions: In vitro studies demonstrated complete receptor occupancy by motix starting at a concentration of 3nM. Increasing concentrations resulted in longer duration of receptor occupancy. Mobilization of CD34+ cells to PB was observed within 2 hours after motix injection (1.25mg/kg), peaked at 12-16 hours, and remained elevated (>20 CD34+ cells/μL) for >24 hours post-motix. These PK/PD characteristics of motix result in rapid and robust PB CD34+ HSPC mobilization (median 116.0 CD34+ cells/μL); enabling 88.8% of patients to collect ≥6x10 6 CD34+ cells/kg in 1 LP with 1 dose of motix added to G. Furthermore, the extended PD effect of motix supports a flexible administration window that allows for LP to be performed > 24 hours post-motix administration.

The importance of CXCR4 expression in tumor stroma as a potential biomarker in pancreatic cancer

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the main causes of cancer mortality in the world. A characteristic feature of this cancer is that a large part of the tumor volume is composed of a stroma with different cells and factors. Among these, we can highlight the cytokines, which perform their function through binding to their receptors. Given the impact of the CXCR4 receptor in the interactions between tumor cells and their microenvironment and its involvement in important signaling pathways in cancer, it is proposed as a very promising prognostic biomarker and as a goal for new targeted therapies. Numerous studies analyze the expression of CXCR4 but we suggest focusing on the expression of CXCR4 in the stroma.MethodsExpression of CXCR4 in specimens from 33 patients with PDAC was evaluated by immunohistochemistry techniques and matched with clinicopathological parameters, overall and disease-free survival rates.ResultsThe percentage of stroma was lower in non-tumor tissue (32.4 ± 5.2) than in tumor pancreatic tissue (67.4 ± 4.8), P-value = 0.001. The level of CXCR4 expression in stromal cells was diminished in non-tumor tissue (8.7 ± 4.6) and higher in tumor pancreatic tissue (23.5 ± 6.1), P-value = 0.022. No significant differences were identified in total cell count and inflammatory cells between non-tumor tissue and pancreatic tumor tissue. No association was observed between CXCR4 expression and any of the clinical or pathological data, overall and disease-free survival rates. Analyzing exclusively the stroma of tumor samples, the CXCR4 expression was associated with tumor differentiation, P-value = 0.05.ConclusionsIn this study, we reflect the importance of CXCR4 expression in the stroma of patients diagnosed with PDAC. Our results revealed a high CXCR4 expression in the tumor stroma, which is related to a poor tumor differentiation. On the contrary, we could not find an association between CXCR4 expression and survival and the rest of the clinicopathological variables. Focusing the study on the CXCR4 expression in the tumor stroma could generate more robust results. Therefore, we consider it key to develop more studies to enlighten the role of this receptor in PDAC and its implication as a possible biomarker.

The regulatory role of cancer stem cell marker gene CXCR4 in the growth and metastasis of gastric cancer

Single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (bulk RNA-seq) are increasingly used for screening genes involved in carcinogenesis due to their capacity for dissecting cellular heterogeneity. This study aims to reveal the molecular mechanism of the cancer stem cells (CSCs) marker gene CXCR4 in gastric cancer (GC) growth and metastasis through scRNA-seq combined with bulk RNA-seq. GC-related scRNA-seq data were downloaded from the GEO database, followed by UMAP cluster analysis. Non-malignant cells were excluded by the K-means algorithm. Bulk RNA-seq data and clinical sample information were downloaded from the UCSC Xena database. GO and KEGG pathway analyses validated the correlation between genes and pathways. In vitro and in vivo functional assays were used to examine the effect of perturbed CXCR4 on malignant phenotypes, tumorigenesis, and liver metastasis. A large number of highly variable genes were identified in GC tissue samples. The top 20 principal components were selected, and the cells were clustered into 6 cell types. The C4 cell cluster from malignant epithelial cells might be CSCs. CXCR4 was singled out as a marker gene of CSCs. GC patients with high CXCR4 expression had poor survival. Knockdown of CXCR4 inhibited the malignant phenotypes of CSCs in vitro and curtailed tumorigenesis and liver metastasis in nude mice. CSC marker gene CXCR4 may be a key gene facilitating malignant phenotypes of CSCs, which thus promotes tumor growth and liver metastasis of GC.

PFKFB3 promotes sepsis-induced acute lung injury by enhancing NET formation by CXCR4hi neutrophils

CXCR4hi neutrophils, which are a subset of neutrophils with high CXCR4 expression, are important contributors to sepsis-induced acute lung injury (ALI). PFKFB3, a key glycolysis gene, plays an essential role in neutrophil inflammatory activation. However, the specific involvement of PFKFB3 in sepsis-induced ALI remains unclear. Here, we observed that PFKFB3 was upregulated in CXCR4hi neutrophils and facilitated sepsis-induced ALI. Mechanistically, we observed that PFKFB3 promoted sepsis-induced ALI by enhancing neutrophil extracellular trap (NET) formation by CXCR4hi neutrophils. Further study indicated that PFKFB3 promoted NET formation by upregulating glycolytic metabolism in CXCR4hi neutrophils. In summary, our study uncovered a new mechanism by which CXCR4hi neutrophils trigger sepsis-induced ALI by promoting NET formation, which is supported by PFKFB3-mediated glycolytic metabolism.

Neoantigen-specific CD8 T cells with high structural avidity preferentially reside in and eliminate tumors

The success of cancer immunotherapy depends in part on the strength of antigen recognition by T cells. Here, we characterize the T cell receptor (TCR) functional (antigen sensitivity) and structural (monomeric pMHC-TCR off-rates) avidities of 371 CD8 T cell clones specific for neoantigens, tumor-associated antigens (TAAs) or viral antigens isolated from tumors or blood of patients and healthy donors. T cells from tumors exhibit stronger functional and structural avidity than their blood counterparts. Relative to TAA, neoantigen-specific T cells are of higher structural avidity and, consistently, are preferentially detected in tumors. Effective tumor infiltration in mice models is associated with high structural avidity and CXCR3 expression. Based on TCR biophysicochemical properties, we derive and apply an in silico model predicting TCR structural avidity and validate the enrichment in high avidity T cells in patients’ tumors. These observations indicate a direct relationship between neoantigen recognition, T cell functionality and tumor infiltration. These results delineate a rational approach to identify potent T cells for personalized cancer immunotherapy.

The CXCR4/miR-1910-5p/MMRN2 Axis Is Involved in Corneal Neovascularization by Affecting Vascular Permeability.

Chemokine receptor 4 (CXCR4) plays an essential role in the early stage of corneal neovascularization (CNV), but the underlying key molecular mechanism has yet to be addressed. This study aimed to explore the new molecular mechanism of CXCR4 in CNV and the related pathological events. CXCR4 was assayed by immunofluorescence or Western blotting. The function of the supernatant from hypoxia-treated human corneal epithelial cells (HCE-T) cells was examined by culturing with human umbilical vein endothelial cells. MicroRNA sequencing was used to detect the downstream microRNAs upon CXCR4 knockdown and analyzed by preliminary bioinformatics. The proangiogenic functions and downstream target genes of microRNA were investigated by gene interference and luciferase assay. An alkali-burned murine model was introduced to examine the function and mechanism of miR-1910-5p in vivo. High CXCR4 expression was confirmed in corneal tissues of patients with CNV and hypoxic HCE-T cells. The supernatant from hypoxia-treated HCE-T cells is involved in the CXCR4-mediated angiogenesis of human umbilical vein endothelial cells. Notably, miR-1910-5p was demonstrated to be at a high level in wild-type HCE-T cells and its supernatant, and in CNV patient tears. The proangiogenic functions of miR-1910-5p were demonstrated with the assays of cell migration, tube formation, and aortic ring. Moreover, miR-1910-5p significantly inhibited multimerin-2 expression by targeting its 3' untranslated region and caused significant extracellular junctional defects in human umbilical vein endothelial cells. MiR-1910-5p antagomir could significantly increase multimerin-2 level and decrease vascular leakage, and ultimately inhibit CNV in a murine model. Our results revealed a novel CXCR4-mediated mechanism and proved that targeting the miR-1910-5p/multimerin-2 pathway could be a promising therapeutic target for CNV.

In vivo validation of 68Ga-labeled AMD3100 conjugates for PET imaging of CXCR4

IntroductionThe chemokine receptor CXCR4 has been shown to be over-expressed in multiple types of cancer and is usually associated with aggressive phenotypes and poor prognosis. Successfully targeting and imaging the expression level of this receptor in tumours could inform treatment selection and facilitate patient stratification. MethodsKnown conjugates of AMD3100 that are specific to CXCR4 have been radiolabelled with gallium-68 and evaluated in naïve and tumour-bearing mice. Tumour uptake of the radiotracers was compared to the known CXCR4-specific PET imaging agent, [68Ga]Pentixafor. ResultsEx vivo biodistribution in naïve animals showed CXCR4-mediated uptake in the liver with both radiotracers, confirmed by blocking experiments with the high affinity CXCR4 antagonist Cu2CB-Bicyclam (IC50 = 3 nM). PET/CT imaging studies revealed one tracer to have a higher accumulation in the tumour (SUVMean of 0.89 ± 0.14 vs 0.32 ± 0.11). CXCR4-specificity of the best performing tracer was confirmed by administration of a blocking dose of Cu2CB-Bicyclam, showing a 3- and 6-fold decrease in tumour and liver uptake, respectively. Conclusion and advances in knowledgeThis initial study offers some interesting insights on the impact of some structural features on the pharmacokinetics and metabolic stability of the radiotracer. Additionally, as Pentixafor only binds to human CXCR4, the development of CXCR4-targeted imaging agents that bind to the receptor across different species could significantly help with preclinical evaluation of new CXCR4-specific therapeutics.

Abstract 6294: CXCR5 is a very promising drug target for the development of antibody-drug conjugates to treat patients with lymphoma

Abstract Introduction: The chemokine receptor CXCR5 is highly expressed in tumor cells from different lymphoma types and represents a viable drug target for the development of antibody-drug conjugates (ADC) to treat patients with lymphoma. Methods: Immunohistochemistry of human tissues of different lymphoma types were stained using antibodies against human CXCR5, CD20, CD70 and CD79b. Slides were examined by a pathologist and scored for expression. CXCR5 expression on tumor cell lines was analyzed by flow cytometry. Cell surface receptor density was analyzed by Quantibrite ™ PE-beads. Evaluation of antibody internalization was performed using the Operetta High Content Imaging System. NOD/SCID mice were transplanted subcutaneously with lymphoma patient-derived (PDX) tumor specimens and treated with 2mg/kg or 10mg/kg VIP924 CXCR5-ADC or isotype control. Results: CXCR5 reveals very low to no expression in most tissues except for lymph nodes. Expression of CXCR5 and other B-cell targets like CD19, CD20, CD70 and CD79b was analyzed on patient-derived tumor samples. High expression of CXCR5 was found on naïve and previously treated diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), and chronic lymphocytic leukemia (CLL) samples. Based on these results, we developed a CXCR5 targeted ADC with a novel, highly potent kinesin spindle protein inhibitor (KSPi) payload linked via a legumain-cleavable linker (VIP924). To compare the performance of KSPi ADCs, the same effector chemistry was attached to antibodies against other B-cell targets and tested in cytotoxicity assays in various cell lines. CXCR5-targeted ADC demonstrates significantly higher activity compared to the other ADCs tested except for the CD79b ADC with equal potency. VIP924 was then tested in vivo in different PDX tumor mouse models with different levels of CXCR5 expression. In the LY2264 and HBL-1 DLBCL models, we obtained a tumor growth inhibition of 68% and 100% respectively compared to isotype control. The median survival time for the isotype control group was 29 days and median survival time for the mice treated with 10mg/kg VIP924 could not be determined as all mice survived until the end of the study (Day 37). No effect on body weight or any adverse effects in the VIP924 treated mice were observed. Conclusions: CXCR5 is a highly attractive target in hematological malignancies such as DLBCL, MCL, and FL due to high protein expression and almost no expression in healthy tissues. CXCR5-targeting ADC with KSPi payload showed high potency and superiority to other B-cell-targeted ADCs in vitro on a broad range of lymphoma cell lines. VIP924 with a novel legumain-cleavable linker showed activity in in vivo PDX models from lymphoma patients. Due to the high CXCR5 expression found in relapsed DLBCL patients, VIP924 may bring promising new treatment options for previously treated patients with lymphoma. Citation Format: Tibor Schomber, Beatrix Stelte-Ludwig, Amy J. Johnson, Oliver von Ahsen, Christoph Schatz, Raquel Izumi, Ahmed Hamdy, Hans-Georg Lerchen. CXCR5 is a very promising drug target for the development of antibody-drug conjugates to treat patients with lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6294.

Dynamics of CXCR4 positive circulating tumor cells in prostate cancer patients during radiotherapy.

Ablative radiotherapy is a highly efficient treatment modality for patients with metastatic prostate cancer (PCa). However, a subset of patients does not respond. Currently, this subgroup with bad prognosis cannot be identified before disease progression. We hypothesize that markers indicative of radioresistance, stemness and/or bone tropism may have a prognostic potential to identify patients profiting from metastases-directed radiotherapy. Therefore, circulating tumor cells (CTCs) were analyzed in patients with metastatic PCa (n=24) during radiotherapy with CellSearch, multicolor flow cytometry and imaging cytometry. Analysis of copy-number alteration indicates a polyclonal CTC population that changes after radiotherapy. CTCs were found in 8 out of 24 patients (33.3%) and were associated with a shorter time to biochemical progression after radiotherapy. Whereas the total CTC count dropped after radiotherapy, a chemokine receptor CXCR4-expressing subpopulation representing 28.6% of the total CTC population remained stable up to 3 months. At once, we observed higher chemokine CCL2 plasma concentrations and proinflammatory monocytes. Additional functional analyses demonstrated key roles of CXCR4 and CCL2 for cellular radiosensitivity, tumorigenicity and stem-like potential in vitro and in vivo. Moreover, a high CXCR4 and CCL2 expression was found in bone metastasis biopsies of PCa patients. In summary, panCK+ CXCR4+ CTCs may have a prognostic potential in patients with metastatic PCa treated with metastasis-directed radiotherapy.