The Chemokine receptor CXCR4 and its ligand stromal derived factor-1 (SDF-1/CXCL12) are important players involved in cross-talk between leukemia cells and the bone marrow (BM) microenvironment. ...CXCR4 expression is associated with poor prognosis in AML patients with and without the mutated FLT3 gene.CXCL12 which is constrictively secreted from the BM stroma and AML cells is critical for the survival and retention of AML cells within the BM. In vitro, CXCR4 antagonists were shown to inhibit the migration of AML cells in response to CXCL12. In addition, such antagonists were shown to inhibit the survival and colony forming potential of AML cells and abrogate the protective effects of stromal cells on chemotherapy-induced apoptosis in AML cells. In vivo, using immune deficient mouse models, CXCR4 antagonists were found to induce the mobilization of AML cells and progenitor cells into the circulation and enhance anti leukemic effects of chemotherapy. The hypothesis that CXCL12/CXCR4 interactions contribute to the resistance of AML cells to signal transduction inhibitor- and chemotherapy-induced apoptosis is currently being tested in a series of Phase I/II studies in humans.
Programmed cell death 1 (PD-1) inhibitors have limited effect in pancreatic ductal adenocarcinoma (PDAC), underscoring the need to co-target alternative pathways. CXC chemokine receptor 4 (CXCR4) ...blockade promotes T cell tumor infiltration and is synergistic with anti-PD-1 therapy in PDAC mouse models. We conducted a phase IIa, open-label, two-cohort study to assess the safety, efficacy and immunobiological effects of the CXCR4 antagonist BL-8040 (motixafortide) with pembrolizumab and chemotherapy in metastatic PDAC (NCT02826486). The primary outcome was objective response rate (ORR). Secondary outcomes were overall survival (OS), disease control rate (DCR) and safety. In cohort 1, 37 patients with chemotherapy-resistant disease received BL-8040 and pembrolizumab. The DCR was 34.5% in the evaluable population (modified intention to treat, mITT; N = 29), including nine patients (31%) with stable disease and one patient (3.4%) with partial response. Median OS (mOS) was 3.3 months in the ITT population. Notably, in patients receiving study drugs as second-line therapy, the mOS was 7.5 months. BL-8040 increased CD8
effector T cell tumor infiltration, decreased myeloid-derived suppressor cells (MDSCs) and further decreased circulating regulatory T cells. In cohort 2, 22 patients received BL-8040 and pembrolizumab with chemotherapy, with an ORR, DCR and median duration of response of 32%, 77% and 7.8 months, respectively. These data suggest that combined CXCR4 and PD-1 blockade may expand the benefit of chemotherapy in PDAC and warrants confirmation in subsequent randomized trials.
Pancreatic ductal adenocarcinoma (PDAC) is largely unresponsive to checkpoint inhibitors. Blockade of the CXCR4/CXCL12 axis increases intratumoral trafficking of activated T cells while restraining ...immunosuppressive elements. This study evaluates dual blockade of CXCR4 and PD1 with chemotherapy in PDAC.
Multicenter, single-arm, phase II study to evaluate the safety and efficacy of motixafortide and pembrolizumab combined with chemotherapy in patients with
metastatic PDAC and disease progression on front-line gemcitabine-based therapy (NCT02826486). Subjects received a priming phase of motixafortide daily on days 1-5, followed by repeated cycles of motixafortide twice a week; pembrolizumab every 3 weeks; and nanoliposomal irinotecan, fluorouracil, and leucovorin every 2 weeks (NAPOLI-1 regimen). The primary objective was objective response rate (ORR). Secondary objectives included overall survival (OS), progression-free survival (PFS), disease control rate (DCR), safety, and tolerability.
A total of 43 patients were enrolled. The ORR according to RECISTv1.1 was 21.1% with confirmed ORR of 13.2%. The DCR was 63.2% with median duration of clinical benefit of 5.7 months. In the intention-to-treat population, median PFS was 3.8 months and median OS was 6.6 months. The triple combination was safe and well tolerated, with toxicity comparable with the NAPOLI-1 regimen. Notably, the incidence of grade 3 or higher neutropenia and infection was 7%, lower than expected for this chemotherapy regimen.
Triple combination of motixafortide, pembrolizumab, and chemotherapy was safe and well tolerated, and showed signs of efficacy in a population with poor prognosis and aggressive disease.
To explore the functional consequences of possible cross-talk between the CXCR4/CXCL12 and the sphingosine-1-phosphate (S1P) pathways in multiple myeloma (MM) cells and to evaluate the effect of S1P ...targeting with the FTY720 modulator as a potential anti-MM therapeutic strategy.
S1P targeting with FTY720 induces MM cell apoptosis. The combination of FTY720 with the SPHK1 inhibitor SKI-II results in synergistic inhibition of MM growth. CXCR4/CXCL12-enhanced expression correlates with reduced MM cell sensitivity to both FTY720 and SKI-II inhibitors, and with SPHK1 coexpression in both cell lines and primary MM bone marrow (BM) samples, suggesting regulative cross-talk between the CXCR4/CXCL12 and SPHK1 pathways in MM cells. FTY720 was found to directly target CXCR4. FTY720 profoundly reduces CXCR4 cell-surface levels and abrogates the CXCR4-mediated functions of migration toward CXCL12 and signaling pathway activation. Moreover, FTY720 cooperates with bortezomib, inducing its cytotoxic activity and abrogating the bortezomib-mediated increase in CXCR4 expression. FTY720 effectively targets bortezomib-resistant cells and increases their sensitivity to bortezomib, promoting DNA damage. Finally, in a recently developed novel xenograft model of CXCR4-dependent systemic MM with BM involvement, FTY720 treatment effectively reduces tumor burden in the BM of MM-bearing mice. FTY720 in combination with bortezomib demonstrates superior tumor growth inhibition and abrogates bortezomib-induced CXCR4 increase on MM cells.
Altogether, our work identifies a cross-talk between the S1P and CXCR4 pathways in MM cells and provides a preclinical rationale for the therapeutic application of FTY720 in combination with bortezomib in patients with MM.
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CXCR4 expression in neuroblastoma tumors correlates with disease severity. In this study, we describe mechanisms by which CXCR4 signaling controls neuroblastoma tumor growth and response to therapy. ...We found that overexpression of CXCR4 or stimulation with CXCL12 supports neuroblastoma tumorigenesis. Moreover, CXCR4 inhibition with the high-affinity CXCR4 antagonist BL-8040 prevented tumor growth and reduced survival of tumor cells. These effects were mediated by the upregulation of miR-15a/16-1, which resulted in downregulation of their target genes BCL-2 and cyclin D1, as well as inhibition of ERK. Overexpression of miR-15a/16-1 in cells increased cell death, whereas antagomirs to miR-15a/16-1 abolished the proapoptotic effects of BL-8040. CXCR4 overexpression also increased miR-15a/16-1, shifting their oncogenic dependency from the BCL-2 to the ERK signaling pathway. Overall, our results demonstrate the therapeutic potential of CXCR4 inhibition in neuroblastoma treatment and provide a rationale to test combination therapies employing CXCR4 and BCL-2 inhibitors to increase the efficacy of these agents.
These results provide a mechanistic rationale for combination therapy of CXCR4 and BCL-2 inhibitors to treat a common and commonly aggressive pediatric cancer.
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Objectives Carcinoma-associated fibroblasts are reported to communicate microenvironment-derived signals through chemokine/chemokine receptor interaction, influencing carcinogenesis. We sought to ...characterize roles of CXCL12/CXCR4 in crosstalk between non–small cell lung cancer epithelial cell and carcinoma-associated fibroblasts and in tumor growth. Methods Non–small cell lung cancer tumor samples obtained at surgery and from tumor arrays, as well as primary carcinoma-associated fibroblast and epithelial cell lines generated from fresh tumors, were assessed for CXCL12/CXCR4 expression, tissue localization, and production. Colony assays, extracellular signal–regulated kinase signaling, and chemokine production were measured to assess cancer cell responsiveness to CXCL12 stimulation with or without CXCR4 antagonists. Results CXCL12 and CXCR4 were detected in all major subtypes of non–small cell lung cancer. CXCL12-expressing carcinoma-associated fibroblasts were mostly located near CXCL12-negative tumor cells, whereas CXCL12-positive tumor cells were mostly surrounded by CXCL12-negative stroma. Intratumoral CXCL12 levels were significantly higher than serum levels. CXCL12 expression correlated with advanced disease stage. In vitro, tumor cell lines produced variable amounts of CXCL12 and expressed high levels of CXCR4. Carcinoma-associated fibroblasts cell lines produced high amounts of CXCL12 and expressed variable levels of CXCR4. Stimulation of non–small cell lung cancer neoplastic cells with CXCL12 increased colony-forming capacity, induced extracellular signal–regulated kinase phosphorylation, and production of the proinflammatory chemokine CCL20. CXCR4 antagonists attenuated these effects. Conclusions Interaction between carcinoma-associated fibroblasts and tumor epithelial cells through the CXCL12/CXCR4 axis plays a role in non–small cell lung cancer tumor proliferation, marking this axis as a target for immune intervention.
Hematopoietic stem and progenitor cells (HSPCs) are a small population of undifferentiated cells that have the capacity for self-renewal and differentiate into all blood cell lineages. These cells ...are the most useful cells for clinical transplantations and for regenerative medicine. So far, it has not been possible to expand adult hematopoietic stem cells (HSCs) without losing their self-renewal properties. CD74 is a cell surface receptor for the cytokine macrophage migration inhibitory factor (MIF), and its mRNA is known to be expressed in HSCs. Here, we demonstrate that mice lacking CD74 exhibit an accumulation of HSCs in the bone marrow (BM) due to their increased potential to repopulate and compete for BM niches. Our results suggest that CD74 regulates the maintenance of the HSCs and CD18 expression. Its absence leads to induced survival of these cells and accumulation of quiescent and proliferating cells. Furthermore, in in vitro experiments, blocking of CD74 elevated the numbers of HSPCs. Thus, we suggest that blocking CD74 could lead to improved clinical insight into BM transplant protocols, enabling improved engraftment.
Background We assessed the mechanism by which multiple myeloma (MM) shapes the bone marrow (BM) microenvironment and affects MΦ polarization. Methods In vivo xenograft model of BM-disseminated human ...myeloma, as well as analysis of MM cell lines, stromal components, and primary samples from patients with MM, was utilized. Results Analysis of the BM from MM-bearing mice inoculated with human CXCR4-expressing RPMI8226 cells revealed a significant increase in M2 MΦ cell numbers (p < 0.01). CXCL13 was one of the most profoundly increased factors upon MM growth with increased levels in the blood of MM-bearing animals. Myeloid cells were the main source of the increased murine CXCL13 detected in MM-infiltrated BM. MM cell lines induced CXCL13 and concurrent expression of M2 markers (MERTK, CD206, CD163) in co-cultured human MΦ in vitro. Interaction with MΦ reciprocally induced CXCL13 expression in MM cell lines. Mechanistically, TGFbeta signaling was involved in CXCL13 induction in MM cells, while BTK signaling was implicated in MM-stimulated increase of CXCL13 in MΦ. Recombinant CXCL13 increased RANKL expression and induced TRAP+ osteoclast (OC) formation in vitro, while CXCL13 neutralization blocked these activities. Moreover, mice inoculated with CXCL13-silenced MM cells developed significantly lower BM disease. Reduced tumor load correlated with decreased numbers of M2 MΦ in BM, decreased bone disease, and lower expression of OC-associated genes. Finally, higher levels of CXCL13 were detected in the blood and BM samples of MM patients in comparison with healthy individuals. Conclusions Altogether, our findings suggest that bidirectional interactions of MΦ with MM tumor cells result in M2 MΦ polarization, CXCL13 induction, and subsequent OC activation, enhancing their ability to support bone resorption and MM progression. CXCL13 may thus serve as a potential novel target in MM.
Irradiation‐induced alopecia and dermatitis (IRIAD) are two of the most visually recognized complications of radiotherapy, of which the molecular and cellular basis remains largely unclear. By ...combining scRNA‐seq analysis of whole skin‐derived irradiated cells with genetic ablation and molecular inhibition studies, we show that senescence‐associated IL‐6 and IL‐1 signaling, together with IL‐17 upregulation and CCR6+‐mediated immune cell migration, are crucial drivers of IRIAD. Bioinformatics analysis colocalized irradiation‐induced IL‐6 signaling with senescence pathway upregulation largely within epidermal hair follicles, basal keratinocytes, and dermal fibroblasts. Loss of cytokine signaling by genetic ablation in IL‐6−/− or IL‐1R−/− mice, or by molecular blockade, strongly ameliorated IRIAD, as did deficiency of CCL20/CCR6‐mediated immune cell migration in CCR6−/− mice. Moreover, IL‐6 deficiency strongly reduced IL‐17, IL‐22, CCL20, and CCR6 upregulation, whereas CCR6 deficiency reciprocally diminished IL‐6, IL‐17, CCL3, and MHC upregulation, suggesting that proximity‐dependent cellular cross talk promotes IRIAD. Therapeutically, topical application of Janus kinase blockers or inhibition of T‐cell activation by cyclosporine effectively reduced IRIAD, suggesting the potential of targeted approaches for the treatment of dermal side effects in radiotherapy patients.
Synopsis
Irradiation‐induced alopecia and dermatitis (IRIAD) represent two of the most prominent side effects of radiotherapy in the skin. This study utilized scRNA‐seq analysis to identify driving factors of IRIAD in order to facilitate development of targeted therapeutic approaches for its prevention.
IRIAD in mice is strongly associated with upregulation of senescence pathways involving IL‐6 and IL‐1 signaling, together with IL‐17 signaling.
Loss of IL‐6 and IL‐1 signaling, or of CCL20/CCR6‐mediated immune cell migration strongly ameliorated IRIAD, while simultaneously reducing irradiation‐induced cellular senescence.
IL‐6‐deficiency strongly reduced IL‐17, CCL20, and CCR6 upregulation, while loss of CCR6‐mediated immune cell migration reciprocally diminished IL‐6 and IL‐17 upregulation, and loss of immune privilege.
IRIAD is effectively ameliorated by treatment with Janus kinases blockers or cyclosporine A.
Irradiation‐induced alopecia and dermatitis (IRIAD) represent two of the most prominent side effects of radiotherapy in the skin. In this study, Paldor et al applied scRNA‐seq analysis to identify driving factors of IRIAD in order to facilitate the development of targeted therapeutic approaches for its prevention.
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