TET2-STAT3-CXCL5 nexus promotes neutrophil lipid transfer to fuel lung adeno-to-squamous transition.

Phenotypic plasticity is a rising cancer hallmark, and lung adeno-to-squamous transition (AST) triggered by LKB1 inactivation is significantly associated with drug resistance. Mechanistic insights into AST are urgently needed to identify therapeutic vulnerability in LKB1-deficient lung cancer. Here, we find that ten-eleven translocation (TET)-mediated DNA demethylation is elevated during AST in KrasLSL-G12D/+; Lkb1L/L (KL) mice, and knockout of individual Tet genes reveals that Tet2 is required for squamous transition. TET2 promotes neutrophil infiltration through STAT3-mediated CXCL5 expression. Targeting the STAT3-CXCL5 nexus effectively inhibits squamous transition through reducing neutrophil infiltration. Interestingly, tumor-infiltrating neutrophils are laden with triglycerides and can transfer the lipid to tumor cells to promote cell proliferation and squamous transition. Pharmacological inhibition of macropinocytosis dramatically inhibits neutrophil-to-cancer cell lipid transfer and blocks squamous transition. These data uncover an epigenetic mechanism orchestrating phenotypic plasticity through regulating immune microenvironment and metabolic communication, and identify therapeutic strategies to inhibit AST.

CXCL5 activates CXCR2 in nociceptive sensory neurons to drive joint pain and inflammation in experimental gouty arthritis.

Gouty arthritis evokes joint pain and inflammation. Mechanisms driving gout pain and inflammation remain incompletely understood. Here we show that CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to drive gout pain and inflammation. CXCL5 expression was increased in ankle joints of gout arthritis model mice, whereas CXCR2 showed expression in joint-innervating sensory neurons. CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to trigger TRPA1 activation, resulting in hyperexcitability and pain. Neuronal CXCR2 coordinates with neutrophilic CXCR2 to contribute to CXCL5-induced neutrophil chemotaxis via triggering CGRP- and substance P-mediated vasodilation and plasma extravasation. Neuronal Cxcr2 deletion ameliorates joint pain, neutrophil infiltration and gait impairment in model mice. We confirmed CXCR2 expression in human dorsal root ganglion neurons and CXCL5 level upregulation in serum from male patients with gouty arthritis. Our study demonstrates CXCL5-neuronal CXCR2-TRPA1 axis contributes to gouty arthritis pain, neutrophil influx and inflammation that expands our knowledge of immunomodulation capability of nociceptive sensory neurons.

Osteocytes support bone metastasis of melanoma cells by CXCL5.

Bone metastasis is a common complication of certain cancers such as melanoma. The spreading of cancer cells into the bone is supported by changes in the bone marrow environment. The specific role of osteocytes in this process is yet to be defined. By RNA-seq and chemokines screening we show that osteocytes release the chemokine CXCL5 when they are exposed to melanoma cells. Osteocytes-mediated CXCL5 secretion enhanced the migratory and invasive behaviour of melanoma cells. When the expression of the CXCL5 receptor, CXCR2, was down-regulated in melanoma cells in vitro, we observed a significant decrease in melanoma cell migration in response to osteocytes. Furthermore, melanoma cells with down-regulated CXCR2 expression showed less bone metastasis and less bone loss in the bone metastasis model in vivo. Furthermore, when simultaneously down-regulating CXCL5 in osteocytes and CXCR2 in melanoma cells, melanoma progression was abrogated in vivo. In summary, these data suggest a significant role of osteocytes in bone metastasis of melanoma, which is mediated through the CXCL5-CXCR2 pathway.

A2AR-mediated CXCL5 upregulation on macrophages promotes NSCLC progression via NETosis.

Tumor-associated macrophages (TAMs) are abundant in tumors and interact with tumor cells, leading to the formation of an immunosuppressive microenvironment and tumor progression. Although many studies have explored the mechanisms underlying TAM polarization and its immunosuppressive functions, understanding of its progression remains limited. TAMs promote tumor progression by secreting cytokines, which subsequently recruit immunosuppressive cells to suppress the antitumor immunity. In this study, we established an in vitro model of macrophage and non-small cell lung cancer (NSCLC) cell co-culture to explore the mechanisms of cell-cell crosstalk. We observed that in NSCLC, the C-X-C motif chemokine ligand 5 (CXCL5) was upregulated in macrophages because of the stimulation of A2AR by adenosine. Adenosine was catalyzed by CD39 and CD73 in macrophages and tumor cells, respectively. Nuclear factor kappa B (NFκB) mediated the A2AR stimulation of CXCL5 upregulation in macrophages. Additionally, CXCL5 stimulated NETosis in neutrophils. Neutrophil extracellular traps (NETs)-treated CD8+ T cells exhibited upregulation of exhaustion-related and cytosolic DNA sensing pathways and downregulation of effector-related genes. However, A2AR inhibition significantly downregulated CXCL5 expression and reduced neutrophil infiltration, consequently alleviating CD8+ T cell dysfunction. Our findings suggest a complex interaction between tumor and immune cells and its potential as therapeutic target.

Prognostic marker CXCL5 in glioblastoma polyformis and its mechanism of immune invasion.

Glioblastoma multiforme (GBM) is the most aggressive brain cancer with a poor prognosis. Therefore, the correlative molecular markers and molecular mechanisms should be explored to assess the occurrence and treatment of glioma.WB and qPCR assays were used to detect the expression of CXCL5 in human GBM tissues. The relationship between CXCL5 expression and clinicopathological features was evaluated using logistic regression analysis, Wilcoxon symbolic rank test, and Kruskal-Wallis test. Univariate, multivariate Cox regression and Kaplan-Meier methods were used to assess CXCL5 and other prognostic factors of GBM. Gene set enrichment analysis (GSEA) was used to identify pathways associated with CXCL5. The correlation between CXCL5 and tumor immunoinfiltration was investigated using single sample gene set enrichment analysis (ssGSEA) of TCGA data. Cell experiments and mouse subcutaneous transplanted tumor models were used to evaluate the role of CXCL5 in GBM. WB, qPCR, immunofluorescence, and immunohistochemical assays showed that CXCL5 expression was increased in human GBM tissues. Furthermore, high CXCL5 expression was closely related to poor disease-specific survival and overall survival of GBM patients. The ssGSEA suggested that CXCL5 is closely related to the cell cycle and immune response through PPAR signaling pathway. GSEA also showed that CXCL5 expression was positively correlated with macrophage cell infiltration level and negatively correlated with cytotoxic cell infiltration level. CXCL5 may be associated with the prognosis and immunoinfiltration of GBM.

CircNRIP1 promotes proliferation, migration and phenotypic switch of Ang II-induced HA-VSMCs by increasing CXCL5 mRNA stability via recruiting IGF2BP1.

Circular RNA (circRNA) has been found to be differentially expressed and involved in regulating the processes of human diseases, including thoracic aortic dissection (TAD). However, the role and mechanism of circNRIP1 in the TAD process are still unclear. GEO database was used to screen the differentially expressed circRNA and mRNA in type A TAD patients and age-matched normal donors. Angiotensin II (Ang II)-induced human aortic vascular smooth muscle cells (HA-VSMCs) were used to construct TAD cell models. The expression levels of circNRIP1, NRIP1, CXC-motif chemokine 5 (CXCL5) and IGF2BP1 were detected by quantitative real-time PCR. Cell proliferation and migration were determined by EdU assay, transwell assay and wound healing assay. The protein levels of synthetic phenotype markers, contractile phenotype markers, CXCL5 and IGF2BP1 were tested by western blot analysis. The interaction between IGF2BP1 and circNRIP1/CXCL5 was confirmed by RIP assay, and CXCL5 mRNA stability was assessed by actinomycin D assay. CircNRIP1 was upregulated in TAD patients and Ang II-induced HA-VSMCs. Knockdown of circNRIP1 suppressed Ang II-induced proliferation, migration and phenotypic switch of HA-VSMCs. Also, high expression of CXCL5 was observed in TAD patients, and its knockdown could inhibit Ang II-induced HA-VSMCs proliferation, migration and phenotypic switch. Moreover, CXCL5 overexpression reversed the regulation of circNRIP1 knockdown on Ang II-induced HA-VSMCs functions. Mechanistically, circNRIP1 could competitively bind to IGF2BP1 and subsequently enhance CXCL5 mRNA stability. CircNRIP1 might contribute to TAD progression by promoting CXCL5 mRNA stability via recruiting IGF2BP1.

CXCL5 promotes tumorigenesis and angiogenesis of glioblastoma via JAK-STAT/NF-κb signaling pathways.

BACKGROUND: The tumor microenvironment contains chemokines that play a crucial role in various processes, such as tumorigenesis, inflammation, and therapy resistance, in different types of cancer. CXCL5 is a significant chemokine that has been shown to promote tumor proliferation, invasion, angiogenesis, and therapy resistance when overexpressed in various types of cancer. This research aims to investigate the impact of CXCL5 on the biological functions of glioblastoma (GBM). METHODS: The TCGA GBM and GEO databases were utilized to perform transcriptome microarray analysis and oncogenic signaling pathway analysis of CXCL5 in GBM. Validation of CXCL5 expression was performed using RT-qPCR and Western Blot. The impact of CXCL5 on cell proliferation, tumorigenesis, and angiogenesis in GBM was assessed through various methods, including cell proliferation assay, cloning assay, intracranial xenograft tumor models, and tube formation assay. Clinical prognosis was evaluated in 59 samples of gliomas with varying degrees of malignancy (grades 2, 3, and 4) and the TCGA GBM database, based on CXCL5 expression levels. The activities of the JAK-STAT and NF-κB signaling pathways were detected using Western Blot. RESULTS: The expression of CXCL5 was highly enriched in GBM. Moreover, the inhibition of CXCL5 showed a significant efficacy in suppressing cellular proliferation and angiogenesis, resulting in extended survival rates in xenograft mouse models in comparison to the control group. Notably, pretreatment with dapsone exhibited a reversal of the impact of CXCL5 on the formation of colonies and tubes in GBM cells. Elevated expression of CXCL5 was correlated with poor outcomes in GBM patients. Furthermore, the overexpression of CXCL5 has been associated with the activation of JAK-STAT and NF-κB signaling pathways. CONCLUSIONS: CXCL5 plays an important role in tumorigenesis and angiogenesis, indicating the potential for novel therapies targeting CXCL5 in GBM.

CXCL5 suppression recovers neovascularization and accelerates wound healing in diabetes mellitus.

BACKGROUND: Higher chemokine C-X-C motif ligand 5 (CXCL5) level was observed in type 2 diabetes mellitus (DM) patients; however, its role in diabetic vasculopathy was not clarified. This study aimed to explore the impacts and mechanistic insights of CXCL5 in neovasculogenesis and wound healing in DM. METHODS: Endothelial progenitor cells (EPCs) and human aortic endothelial cells (HAECs) were used in vitro. Streptozotocin-induced diabetic mice and Leprdb/JNarl mice were used as type 1 and type 2 DM models. Moreover, CXCL5 knockout mice were used to generate diabetic mice. Hindlimb ischemia surgery, aortic ring assays, matrigel plug assay, and wound healing assay were conducted. RESULTS: CXCL5 concentrations were increased in plasma and EPCs culture medium from type 2 DM patients. CXCL5 neutralizing antibody upregulated vascular endothelial growth factor (VEGF)/stromal cell-derived factor-1 (SDF-1) and promoted cell function in EPCs from type 2 DM patients and high glucose-treated EPCs from non-DM subjects as well as HAECs. CXCL5 directly up-regulated interleukin (IL)-1ß/IL-6/tumor necrosis factor-α and down-regulated VEGF/SDF-1 via ERK/p65 activation through chemokine C-X-C motif receptor 2 (CXCR2). CXCL5 neutralizing antibody recovered the blood flow after hindlimb ischemia, increased circulating EPC number, and enhanced VEGF and SDF-1 expression in ischemic muscle. CXCL5 suppression promoted neovascularization and wound healing in different diabetic animal models. The above observation could also be seen in streptozotocin-induced CXCL5 knockout diabetic mice. CONCLUSIONS: CXCL5 suppression could improve neovascularization and wound healing through CXCR2 in DM. CXCL5 may be regarded as a potential therapeutic target for vascular complications of DM.

Astrocytic CXCL5 hinders microglial phagocytosis of myelin debris and aggravates white matter injury in chronic cerebral ischemia.

BACKGROUND: Chronic cerebral ischemia induces white matter injury (WMI) contributing to cognitive decline. Both astrocytes and microglia play vital roles in the demyelination and remyelination processes, but the underlying mechanism remains unclear. This study aimed to explore the influence of the chemokine CXCL5 on WMI and cognitive decline in chronic cerebral ischemia and the underlying mechanism. METHODS: Bilateral carotid artery stenosis (BCAS) model was constructed to mimic chronic cerebral ischemia in 7-10 weeks old male mice. Astrocytic Cxcl5 conditional knockout (cKO) mice were constructed and mice with Cxcl5 overexpressing in astrocytes were generated by stereotactic injection of adeno-associated virus (AAV). WMI was evaluated by magnetic resonance imaging (MRI), electron microscopy, histological staining and western blotting. Cognitive function was examined by a series of neurobehavioral tests. The proliferation and differentiation of oligodendrocyte progenitor cells (OPCs), phagocytosis of microglia were analyzed via immunofluorescence staining, western blotting or flow cytometry. RESULTS: CXCL5 was significantly elevated in the corpus callosum (CC) and serum in BCAS model, mainly expressed in astrocytes, and Cxcl5 cKO mice displayed improved WMI and cognitive performance. Recombinant CXCL5 (rCXCL5) had no direct effect on the proliferation and differentiation of OPCs in vitro. Astrocytic specific Cxcl5 overexpression aggravated WMI and cognitive decline induced by chronic cerebral ischemia, while microglia depletion counteracted this effect. Recombinant CXCL5 remarkably hindered microglial phagocytosis of myelin debris, which was rescued by inhibition of CXCL5 receptor C-X-C motif chemokine receptor 2 (CXCR2). CONCLUSION: Our study revealed that astrocyte-derived CXCL5 aggravated WMI and cognitive decline by inhibiting microglial phagocytosis of myelin debris, suggesting a novel astrocyte-microglia circuit mediated by CXCL5-CXCR2 signaling in chronic cerebral ischemia.

Renal clear cell carcinoma-derived CXCL5 drives tumor-associated fibroblast formation and facilitates cancer progression.

BACKGROUND: Kidney renal clear cell carcinoma (KIRC, ccRCC) is one of the most common and aggressive subtypes of urinary system cancer. Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) exacerbate the malignant phenotype of KIRC. It is necessary to explore further how KIRC induces normal fibroblasts (NFs) into CAFs. METHODS: The transcriptome data of KIRC was obtained from The Cancer Genome Atlas (TCGA), and the hub-genes and their corresponding functions in the co-expression module were obtained through differential analysis, enrichment analysis, and weighted correlation network analysis (WGCNA) analysis. RT-PCR, western-blot, and Elisa assays were used to detect the expression of CXCL5 (C-X-C Motif Chemokine Ligand 5) in KIRC cells and medium. Western-blot and immunofluorescence were used to demonstrate the transformation of NFs to CAF-like cells and relevant pathways. Human umbilical vein endothelial cells (huvec) were seeded within collagen gel to represent the neo-vascular network. Transwell, scrape, colony formation, and CCK-8 assays were performed to reveal the feedback effect of KIRC cells. RESULTS: Bioinformatics analysis showed that CXCL5 was a core gene in differential expression genes (DEGs) and was associated with extracellular matrix (ECM), which was associated with CAFs. KIRC-derived CXCL5 promoted the conversion of NFs to CAF-like cells. It included morphological and corresponding molecular marker changes. Activation of the JAK/STAT3 pathway was involved in this process. Corresponding, CAFs cells could secrete vascular endothelial growth factor (VEGF), which induced angiogenesis. CXCL5 promoted KIRC invasion and proliferation. CONCLUSIONS: Our research suggested that KIRC-derived CXCL5 could induce NFs to become CAFs-like cells that promote angiogenesis in the TME. The positive feedback of CXCL5 promoted its own invasive growth. The intercellular communication with CXCL5 as the core might be the critical node in the occurrence and development of KIRC.

Targeting CXCL5 in Pancreatic Cancer Cells Inhibits Cancer Xenograft Growth by Reducing Proliferation and Inhibiting EMT Progression.

BACKGROUND: Pancreatic cancer (PC) is the most lethal malignant tumor, with average survival period of about 10 months. C-X-C ligand 5 (CXCL5), an important chemokine for immune cell accumulation in tumor tissues, has been reported to be involved in a variety of human cancers. However, the exact role of CXCL5 in PC progression has not been well defined. METHODS: The expression of CXCL5 in PC was analyzed based on online databases and clinical specimens immunohistochemical staining, and Western blotting of CXCL5 in PC cell lines and patient samples. The correlation between CXCL5 expression and prognosis in PC was explored. The role of CXCL5 in PC was investigated through in vitro and in vivo experiments. RESULTS: The expression of CXCL5 was significantly increased in PC tissues compared with that in pancreas tissues, and CXCL5 high expression predicts poor prognosis in PC patients. Further analyses demonstrated that overexpression of CXCL5 in PC cells was positively related to higher proliferation rate, higher migration ability, and higher EMT markers including SNAI2 and TWIST1 of tumor cells in vitro. Consistently, the knockdown of CXCL5 in PC cells harmed the proliferation rate, migration ability, and expression of EMT indexes of tumor cells in vitro. Importantly, knockdown of CXCL5 inhibited the growth of xenograft tumors in vivo. CONCLUSION: CXCL5 high expression predicts poor prognosis in PC patients. CXCL5 promotes PC cell growth and EMT process. Inhibition of CXCL5 may be a potential therapeutic approach for PC.

CRISPR/Cas9-mediated deletion of Interleukin-30 suppresses IGF1 and CXCL5 and boosts SOCS3 reducing prostate cancer growth and mortality.

BACKGROUND: Metastatic prostate cancer (PC) is a leading cause of cancer death in men worldwide. Targeting of the culprits of disease progression is an unmet need. Interleukin (IL)-30 promotes PC onset and development, but whether it can be a suitable therapeutic target remains to be investigated. Here, we shed light on the relationship between IL30 and canonical PC driver genes and explored the anti-tumor potential of CRISPR/Cas9-mediated deletion of IL30. METHODS: PC cell production of, and response to, IL30 was tested by flow cytometry, immunoelectron microscopy, invasion and migration assays and PCR arrays. Syngeneic and xenograft models were used to investigate the effects of IL30, and its deletion by CRISPR/Cas9 genome editing, on tumor growth. Bioinformatics of transcriptional data and immunopathology of PC samples were used to assess the translational value of the experimental findings. RESULTS: Human membrane-bound IL30 promoted PC cell proliferation, invasion and migration in association with STAT1/STAT3 phosphorylation, similarly to its murine, but secreted, counterpart. Both human and murine IL30 regulated PC driver and immunity genes and shared the upregulation of oncogenes, BCL2 and NFKB1, immunoregulatory mediators, IL1A, TNF, TLR4, PTGS2, PD-L1, STAT3, and chemokine receptors, CCR2, CCR4, CXCR5. In human PC cells, IL30 improved the release of IGF1 and CXCL5, which mediated, via autocrine loops, its potent proliferative effect. Deletion of IL30 dramatically downregulated BCL2, NFKB1, STAT3, IGF1 and CXCL5, whereas tumor suppressors, primarily SOCS3, were upregulated. Syngeneic and xenograft PC models demonstrated IL30's ability to boost cancer proliferation, vascularization and myeloid-derived cell infiltration, which were hindered, along with tumor growth and metastasis, by IL30 deletion, with improved host survival. RNA-Seq data from the PanCancer collection and immunohistochemistry of high-grade locally advanced PCs demonstrated an inverse association (chi-squared test, p = 0.0242) between IL30 and SOCS3 expression and a longer progression-free survival of patients with IL30NegSOCS3PosPC, when compared to patients with IL30PosSOCS3NegPC. CONCLUSIONS: Membrane-anchored IL30 expressed by human PC cells shares a tumor progression programs with its murine homolog and, via juxtacrine signals, steers a complex network of PC driver and immunity genes promoting prostate oncogenesis. The efficacy of CRISPR/Cas9-mediated targeting of IL30 in curbing PC progression paves the way for its clinical use.

Genomically Silent Refractory Gastric Cancer in a Young Patient Exhibits Overexpression of CXCL5.

Gastric cancer is the third leading cause of cancer-related deaths, with more than one million new cases and approximately 841,000 deaths annually worldwide. We report a case of a young patient (25 years old) with an aggressive form of gastric cancer. The patient had previously been treated for Helicobacter pylori (H. pylori), which is a main risk factor for developing gastric cancer. Genetic testing showed an E-cadherin (CDH1) germline mutation of unknown significance. After eight cycles of chemotherapy, a positron emission tomography (PET) scan showed disease progression with an enlarging hypermetabolic right adnexal mass suspicious for metastatic disease. Tumor pathology demonstrated invasive and poorly differentiated gastric carcinoma. The analysis of the tumor biopsy indicated the very high expression of a chemokine, C-X-C motif chemokine 5 (CXCL5). The combination of H. pylori infection with an existence of a rare CDH1 mutation could have contributed to this aggressive gastric cancer.

MicroRNA-873-5p suppresses cell malignant behaviors of thyroid cancer via targeting CXCL5 and regulating P53 pathway.

We aimed to examine the roles of microRNA-873-5p and CXCL5 in thyroid cancer (TC) cells. qRT-PCR was adopted to measure the expression levels of CXCL5 mRNA and microRNA-873-5p in TC cells, and western blot was adopted to evaluate the CXCL5 protein expression level. Bioinformatics analysis was done to predict the upstream gene of CXCL5. Dual-luciferase assay was applied to validate the binding relationship of CXCL5 and the upstream regulatory gene. Cell experiments were done to detect the effects of microRNA-873-5p targeting CXCL5 on malignant progression of cancer cells. Western blot was adopted to demonstrate the phosphorylation level of P53 pathway related-proteins. CXCL5 was upregulated in TC cells and tissues. The results of in vitro assays displayed that CXCL5 downregulation dramatically suppressed the malignant behaviors of TC cells. MicroRNA-873-5p suppressed CXCL5 expression, but the suppressive effect of microRNA-873-5p on TC cells was abolished through CXCL5 overexpression. Additionally, microRNA-873-5p could mediate p53 pathway and thereby inhibit the malignant behaviors of TC cells through targeting CXCL5. In summary, we proved that microRNA-873-5p repressed the malignant behaviors of TC cells through targeting CXCL5 and P53 pathway, indicating that microRNA-873-5p can be a biomarker for TC.

KIF4A promotes tumor progression of bladder cancer via CXCL5 dependent myeloid-derived suppressor cells recruitment.

Although KIF4A has been found to play an important role in a variety of tumors and is closely associated with the activation of immunocytes, its role in bladder cancer (BC) remains unclear. Here, we report increased expression of KIF4A in both lymph node-positive and high grade BC tissues. High expression of KIF4A has been significantly correlated with fewer CD8+ tumor-infiltrating lymphocytes (TILs) and a much worse prognosis in patients with BC. With respect to promoting tumor growth, the expression of KIF4A in promoting tumor growth was more pronounced in immune-competent mice (C57BL/6) than in immunodeficient mice (BALB/C). In addition, the more increased accumulation of myeloid-derived suppressor cells (MDSCs) was observed in tumor-bearing mice with KIF4A overexpression than in the control group. Transwell chemotaxis assays revealed that KIF4A overexpression in T24 cells increased MDSC recruitment. Furthermore, according to ELISA results, CXCL5 was the most noticeably increased cytokine in the KIF4A-transduced BC cells. Additional studies in vitro and in vivo showed that the capability of KIF4A to promote BC cells to recruit MDSCs could be significantly inhibited by anti-CXCL5 antibody. Therefore, our results demonstrated that KIF4A-mediated BC production of CXCL5 led to an increase in MDSC recruitment, which contributed to tumor progression.

CCL7 and TGF-ß secreted by MSCs play opposite roles in regulating CRC metastasis in a KLF5/CXCL5-dependent manner.

CXCL5 is overexpressed in colorectal cancer (CRC) and promotes distant metastasis and angiogenesis of tumors; however, the underlying mechanism that mediates CXCL5 overexpression in CRC remains unclear. Here, we successfully extracted and identified primary mesenchymal stromal cells (MSCs) and verified the promoting effects of tumor-associated MSCs on CRC proliferation and metastasis in vivo and in vitro. We found that MSCs not only promoted the expression of CXCL5 by secreting CCL7 but also secreted TGF-ß to inhibit this process. After secretion, CCL7/CCR1 activated downstream CBP/P300 to acetylate KLF5 to promote CXCL5 transcription, while TGF-ß reversed the effect of KLF5 on transcription activation by regulating SMAD4. Taken together, our results indicate that MSCs in the tumor microenvironment promoted the progression and metastasis of CRC and regulated the expression of CXCL5 in CRC cells by secreting CCL7 and TGF-ß. KLF5 is the key site of these processes and plays a dual role in CXCL5 regulation. MSCs and their secreted factors may serve as potential therapeutic targets in the tumor environment.

Identification of CXCL5 expression as a predictive biomarker associated with response and prognosis of immunotherapy in patients with non-small cell lung cancer.

BACKGROUND: The breakthrough of immunotherapy has revolutionized the treatment of non-small cell lung cancer (NSCLC). However, only a limited part of patients could derive clinical benefits. To study how immune microenvironment (IME) of patients could influence the therapeutic efficacy of immunotherapy, we evaluated the response patterns of NSCLC patients treated with PD-1 inhibitors and analyzed the molecules related to prognosis and efficacy of immunotherapy. METHODS: Tumor samples were collected from 47 NSCLC patients treated with PD-1 inhibitors. RNA expressions of tumor immune-related 289 genes were analyzed using NanoString nCounter. Immune infiltration and correlation between clinical information and expression of immune-related genes were assessed. RESULTS: Unsupervised clustering analysis revealed two groups infiltrated with different immune cells and differentially expressed genes (DEGs) including CXCL5, CXCL9, IDO1, and LAG3 were found between groups. Stratification based on DEGs indicated that the group with high expression of CXCL5 was characterized by neutrophils. Univariate and multivariate Cox analysis further demonstrated that CXCL5 mRNA expression was positively associated with worse progression free survival (PFS). Logistic analyses indicated high CXCL5 was associated with worse response to immunotherapy. CONCLUSIONS: CXCL5 may be a potential biomarker for prognosis and responsiveness to immunotherapy and may be a novel preventive and therapeutic target for NSCLC.

EMT-mediated regulation of CXCL1/5 for resistance to anti-EGFR therapy in colorectal cancer.

The emergence of RAS/RAF mutant clone is the main feature of EGFR inhibitor resistance in KRAS wild-type colon cancer. However, its molecular mechanism is thought to be multifactorial, mainly due to cellular heterogeneity. In order to better understand the resistance mechanism in a single clone level, we successfully isolated nine cells with cetuximab-resistant (CR) clonality from in vitro system. All CR cells harbored either KRAS or BRAF mutations. Characteristically, these cells showed a higher EMT (Epithelial to mesenchymal transition) signature, showing increased EMT markers such as SNAI2. Moreover, the expression level of CXCL1/5, a secreted protein, was significantly higher in CR cells compared to the parental cells. In these CR cells, CXCL1/5 expression was coordinately regulated by SNAI2/NFKB and transactivated EGFR through CXCR/MMPI/EGF axis via autocrine singling. We also observed that combined cetuximab/MEK inhibitor not only showed growth inhibition but also reduced the secreted amounts of CXCL1/5. We further found that serum CXCL1/5 level was positively correlated with the presence of RAS/RAF mutation in colon cancer patients during cetuximab therapy, suggesting its role as a biomarker. These data indicated that the application of serum CXCL1/5 could be a potential serologic biomarker for predicting resistance to EGFR therapy in colorectal cancer.

Sox9/CXCL5 axis facilitates tumour cell growth and invasion in hepatocellular carcinoma.

High rates of metastasis and postsurgical recurrence contribute to the higher mortality of hepatocellular carcinoma (HCC), partly due to cancer stem cell (CSC)-dependent tumorigenesis and metastasis. Sex-determining region Y-box 9 (Sox9) has been previously characterized as a candidate CSC marker of HCC. Here, we observed that the increase of Sox9 significantly promoted HCC cell growth and invasion in cell cultures, whereas knockdown of Sox9 showed the opposite effects, suggesting that Sox9 may regulate the proliferation and invasion of hepatoma cells in an autocrine manner. RNA sequencing, together with functional assays and clinical analyses, identified CXCL5 as a key mediator downstream of Sox9 in HCC cells. Mechanistic studies revealed that Sox9 induced CXCL5 expression by directly binding to a promoter region. Using gain- and loss-of-function approaches, we demonstrated that the intrinsic effective role of Sox9 in hepatoma cell growth and invasion depended on CXCL5, and that blockade of CXCL5/CXCR2 signalling abolished Sox9-triggered HCC cell proliferation and migration. Furthermore, the Sox9/CXCL5 axis activated PI3K-AKT and ERK1/2 signalling which are implicated in regulating HCC cell proliferation and invasion. Finally, the Sox9/CXCL5 axis contributed to the infiltration of neutrophils and macrophages in both tumour and peritumoral tissues from the orthotopic xenograft model. In summary, our data identify the Sox9/CXCL5 axis as an endogenous factor in controlling HCC cell growth and invasion, thereby raising the possibility of pharmacologic intervention with CXCL5/CXCR2 pathway inhibitors in therapy for HCC patients with higher Sox9 expression.

Knockdown of CXCL5 inhibits the invasion, metastasis and stemness of bladder cancer lung metastatic cells by downregulating CD44.

In our previous studies, we found that T24 lung metastatic cancer cells showed high invasion and metastasis abilities and cancer stem cell characteristics compared with T24 primary cancer cells. By screening for the expression of CXC chemokines in both cell lines, we found that CXCL5 is highly expressed in T24-L cells. The aim of this study is to shed light on the relationship of CXCL5 with epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs). RNAi technology was used to decrease CXCL5 expression in the T24-L cell line, and the EMT and CSCs of the shCXCL5 group and the control group were compared. The CXCR2 inhibitor SB225002 was used to inhibit the receptor of CXCL5 to determine the effect of the CXCL5/CXCR2 axis. The knockdown of CXCL5 expression in T24-L cells reduced their EMT and CSC characteristics. RT-PCR and Western blot analyses revealed the downregulation of N-cadherin, Vimentin and CD44. In addition, when CD44 expression was knocked down, the EMT ability of the cells was also inhibited. This phenomenon was most pronounced when both CXCL5 and CD44 were knocked down. CXCL5 and CD44 can affect the EMT and stem cell capacity of T24-L cells through some interaction.