Role of the stromal cell derived factor-1/CXC chemokine receptor 4 axis in the invasion and metastasis of lung cancer and mechanism

Decoding the complex web: cellular and molecular interactions in the lung tumour microenvironment

The lung tumour microenvironment (TME) or stroma is a dynamic space of numerous cells and their released molecules. This complicated web regulates tumour progression and resistance to different modalities. Lung cancer cells in conjunction with their stroma liberate a wide range of factors that dampen antitumor attacks by innate immunity cells like natural killer (NK) cells and also adaptive responses by effector T cells. These factors include numerous growth factors, exosomes and epigenetic regulators, and also anti-inflammatory cytokines. Understanding the intricate interactions between tumour cells and various elements within the lung TME, such as immune and stromal cells can help provide novel strategies for better management and treatment of lung malignancies. The current article discusses the complex network of cells and signalling molecules, which mediate communications in lung TME. By elucidating these multifaceted interactions, we aim to provide insights into potential therapeutic targets and strategies for lung cancer treatment.

A Pilot Study on Qualitative Metabolomics to Characterize Lewis Lung Carcinoma in Mice

Metabolomics is a powerful tool that can be used to identify different stages in cancer development. In this study, the metabolomic profile of Lewis lung carcinoma (LLC) was characterized in C57BL/6 mice bearing LLC tumors. Magnetic resonance spectroscopy (nuclear magnetic resonance-NMR) was applied using a 400 MHz 1H NMR spectrometer. Two types of metabolites (polar and non-polar) were identified on LLC based on the analysis of methanol/water and chloroform extracts collected from lung cancer samples in mice. The investigated metabolomics show that the neoplastic processes of growing LLC on mice may affect carbohydrate; alanine and glutamate; leucine and isoleucine; lysine; creatine; and choline metabolism, whereas hypoxia states were identified due to elevated lactate in lung cancer tissues. The metabolomic profile of Lewis lung carcinoma could be considered to be a valuable biomarker in translational lung cancer research.

Ferulic Acid: A Review of Pharmacology, Toxicology, and Therapeutic Effects on Pulmonary Diseases

Ferulic acid (FA), a prevalent dietary phytochemical, has many pharmacological effects, including anti-oxidation and anti-inflammation effects, and has been widely used in the pharmaceutical, food, and cosmetics industries. Many studies have shown that FA can significantly downregulate the expression of reactive oxygen species and activate nuclear factor erythroid-2-related factor-2/heme oxygenase-1 signaling, exerting anti-oxidative effects. The anti-inflammatory effect of FA is mainly related to the p38 mitogen-activated protein kinase and nuclear factor-kappaB signaling pathways. FA has demonstrated potential clinical applications in the treatment of pulmonary diseases. The transforming growth factor-β1/small mothers against decapentaplegic 3 signaling pathway can be blocked by FA, thereby alleviating pulmonary fibrosis. Moreover, in the context of asthma, the T helper cell 1/2 imbalance is restored by FA. Furthermore, FA ameliorates acute lung injury by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase pathways via toll-like receptor 4, consequently decreasing the expression of downstream inflammatory mediators. Additionally, there is a moderate neuraminidase inhibitory activity showing a tendency to reduce the interleukin-8 level in response to influenza virus infections. Although the application of FA has broad prospects, more preclinical mechanism-based research should be carried out to test these applications in clinical settings. This review not only covers the literature on the pharmacological effects and mechanisms of FA, but also discusses the therapeutic role and toxicology of FA in several pulmonary diseases.

Inhibitory role of puerarin on the A549 lung cancer cell line

BACKGROUND

Although more and more drugs had been proved to be effective in controlling tumor cells, lung cancer was still the leading cause of cancer-related deaths all over the world. This study aimed to investigate the effect and mechanism of puerarin on the invasion and metastasis of A549 lung cancer cell line.

METHODS

A medium containing puerarin was prepared according to the gradient concentration, and 10, 20, and 40 µmol/L were selected as the experimental group (low, medium, and high concentration groups, respectively) according to the cytotoxicity experiment. Meanwhile, 0 µmol/L was used as the control group.

RESULTS

Following administration, metastasis-related indexes were detected by the cell scratch test, cell migration test, gene difference detection, and western blotting. 24 hours after administration, the cell scratch and Transwell showed that the migration ability of A549 cells decreased with the increasing puerarin concentration. The polymerase chain reaction (PCR) and western blotting results demonstrated that the expression of the cell invasion and metastasis-related factor, matrix metallopeptidase 9 (MMP9), was negatively correlated with drug concentration. Further investigation demonstrated that the phosphorylation of extracellular signal-regulated kinase (ERK) was also inhibited.

CONCLUSIONS

Puerarin can inhibit the expression of invasion and metastasis-related factors by inhibiting the phosphorylation of ERK.

The clinicopathological and prognostic value of CXCR4 expression in patients with lung cancer: a meta-analysis

Background

The C-X-C chemokine receptor 4 (CXCR4) has been suggested to play an important role in several types of cancers and is related to biological behaviors connected with tumor progression. However, the clinical significance and application of CXCR4 in lung cancer remain disputable. Thus, we conducted a meta-analysis to investigate the impact of CXCR4 expression on survival and clinicopathological features in lung cancer.

Methods

Comprehensive literature searches were conducted in PubMed, Embase and Web of Science for relevant studies. We pooled hazard ratios (HRs)/odds ratios (ORs) with 95% confidence intervals (CIs) by STATA 12.0 to evaluate the potential value of CXCR4 expression.

Results

Twenty-seven relevant articles involving 2932 patients with lung cancer were included in our meta-analysis. The results revealed that CXCR4 expression was apparently associated with poor overall survival (OS) (HR 1.61, 95% CI 1.42–1.82) and disease-free survival (HR 3.39, 95% CI 2.38–4.83). Furthermore, a significant correlation with poor OS was obvious in non-small cell lung cancer patients (HR 1.59, 95% CI 1.40–1.81) and in patients showing CXCR4 expression in the cytoplasm (HR 2.10, 95% CI 1.55–2.84) and the membrane (HR 1.74, 95% CI 1.24–2.45). CXCR4 expression was significantly associated with men (OR 1.32, 95% CI 1.08–1.61), advanced tumor stages (T3-T4) (OR 2.34, 95% CI 1.28–4.28), advanced nodal stages (N > 0) (OR 2.34, 95% CI 1.90–2.90), distant metastasis (OR 3.65, 95% CI 1.53–8.69), advanced TNM stages (TNM stages III, IV) (OR 3.10, 95% CI 1.95–4.93) and epidermal growth factor receptor (EGFR) expression (OR 2.44, 95% CI 1.44–4.12) but was not associated with age, smoking history, histopathology, differentiation, lymphatic vessel invasion or local recurrence.

Conclusion

High expression of CXCR4 is related to tumor progression and might be an adverse prognostic factor for lung cancer.

Propionate ameliorates diabetes-induced neurological dysfunction through regulating the PI3K/Akt/eNOS signaling pathway

A large body of research has established diabetes-related cognitive deterioration, sometimes known as "diabetic encephalopathy". Current evidence supports that oxidative stress, neuronal apoptosis, and cerebral microcirculation weakness are associated with cognition deficits induced by diabetes. The present study explores the effect of propionate on neurological deficits, cerebral blood flow, and oxidative stress in diabetic mice. Propionate in different doses (37.5, 75 and 150 mg/kg) was orally administrated daily. Here, we show that propionate can markedly improve neurological function, which is correlated with its capabilities of stimulating nitrogen monoxide (NO) production, increasing cerebral microcirculation, suppressing oxidative stress, and reducing neuron loss in the hippocampus. In addition, the results of Western Blotting indicated that the brain-protective function of propionate in streptozocin (STZ)-induced type 1 diabetes mellitus (T1DM) mice is related to phosphoinositide 3-kinase (PI3K)/serine-threonine protein kinase (Akt)/endothelial nitrogen monoxide synthase (eNOS) signaling pathway. In a diabetic mouse model, propionate reduces cerebral microcirculation, hippocampus apoptosis, and neurological impairment. Thus, propionate, now employed as a food preservative, may also help slow diabetes-induced cognitive loss.

Chemokine signaling in cancer-stroma communications

Cancer is a multi-faceted disease in which spontaneous mutation(s) in a cell leads to the growth and development of a malignant new organ that if left undisturbed will grow in size and lead to eventual death of the organism. During this process, multiple cell types are continuously releasing signaling molecules into the microenvironment, which results in a tangled web of communication that both attracts new cell types into and reshapes the tumor microenvironment as a whole. One prominent class of molecules, chemokines, bind to specific receptors and trigger directional, chemotactic movement in the receiving cell. Chemokines and their receptors have been demonstrated to be expressed by almost all cell types in the tumor microenvironment, including epithelial, immune, mesenchymal, endothelial, and other stromal cells. This results in chemokines playing multifaceted roles in facilitating context-dependent intercellular communications. Recent research has started to shed light on these ligands and receptors in a cancer-specific context, including cell-type specificity and drug targetability. In this review, we summarize the latest research with regards to chemokines in facilitating communication between different cell types in the tumor microenvironment.

Stromal Cell-Derived Factor 1α (SDF-1α) in Invasive Breast Cancer: Associations with Vasculo-Angiogenic Factors and Prognostic Significance

(1) Background: Tumour angiogenesis is critical for the progression of neoplasms. A prospective study was designed to examine the utility of stromal cell-derived factor 1α (SDF-1α) and selected vasculo-angiogenic parameters for estimating the probability of disease relapse in 84 primary, operable invasive breast cancer (IBrC) patients (40 (48%) with stage IA and 44 (52%) with stage IIA and IIB). (2) Methods: We explored the prognostic value of the plasma levels of SDF-1α, vascular endothelial growth factor A (VEGF-A), the soluble forms of VEGF receptors type 1 and 2, and the number of circulating endothelial progenitor cells (circulating EPCs) in breast cancer patients. The median follow-up duration was 58 months, with complete follow-up for the first event. (3) Results: According to ROC curve analysis, the optimal cut-off point for SDF-1α (for discriminating between patients at high and low risk of relapse) was 42 pg/mL, providing 57% sensitivity and 75% specificity. Kaplan-Meier curves for disease-free survival (DFS) showed that concentrations of SDF-1α lower than 42 pg/dL together with a VEGFR1 lower than 29.86 pg/mL were significantly associated with shorter DFS in IBrC patients (p = 0.0381). Patients with both SDF-1α lower than 42 pg/dL and a number of circulating EPCs lower than 9.68 cells/µL had significantly shorter DFS (p = 0.0138). (4) Conclusions: Our results imply the clinical usefulness of SDF-1α, sVEGFR1 and the number of circulating EPCs as prognostic markers for breast cancer in clinical settings.

Role of the stromal cell derived factor-1 in the biological functions of endothelial progenitor cells and its underlying mechanisms

Stromal cell derived factor-1 (SDF-1) is a chemokine that plays a critical role in the homing of stem and progenitor cells, including endothelial progenitor cells (EPCs). However, little research has been undertaken to evaluate the roles of SDF-1 in the biological functions of EPCs and related signaling pathways. The present study aimed to investigate the biological functions of EPCs in response to SDF-1, as well as the underlying mechanisms. The effects of SDF-1 treatment on EPC proliferation, migration and tube formation were assessed by performing MTS, Transwell and in vitro tube formation assays, respectively. The phosphorylation status of Akt and ERK was evaluated by western blotting. The present results indicated that SDF-1 treatment enhanced EPC proliferation, migration and tube formation compared with the control group. Furthermore, SDF-1-induced EPC proliferation was significantly reduced following treatment with a C-X-C Motif Chemokine Receptor 4 antagonist (AMD3100), a PI3K inhibitor (LY294002) and the mitogen-activated protein kinase kinase inhibitor (MEK; PD98059). SDF-1-induced migration and angiogenesis were significantly suppressed by the PI3K inhibitor, but not the MEK inhibitor. Moreover, SDF-1 significantly increased the protein expression levels of phosphorylated (p)-Akt and p-ERK; however, SDF-1-induced effects on protein expression were suppressed by AMD3100, LY294002 and PD98059. Thus, SDF-1-induced EPC proliferation was mediated by activation of the Akt and ERK signaling pathways, whereas SDF-1-mediated EPC migration and tube formation only involved activation of the Akt signaling pathway.

Interaction between CXCR4 and EGFR and downstream PI3K/AKT pathway in lung adenocarcinoma A549 cells and transplanted tumor in nude mice

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality all over the world, particularly in China. Metastasis is the main factor resulting in the poor prognosis of patients with NSCLC. CXCR4 and EGFR have been widely studied due to their critical role in tumor metastasis, but it remains more elusive then the relationship between CXCR4 and EGFR. Studies have demonstrated that many tumors have been found the existence of the "cross-talk" between EGFR and CXCR4 signaling pathways. In this context, we explored the relationship between EGFR and CXCR4 signaling pathways in lung cancer invasion and metastasis by both in vitro and in vivo experiments.

The role of CXCR4 in multiple myeloma: Cells' journey from bone marrow to beyond

CXCR4 is a pleiotropic chemokine receptor which acts through its ligand CXCL12 to regulate diverse physiological processes. CXCR4/CXCL12 axis plays a pivotal role in proliferation, invasion, dissemination and drug resistance in multiple myeloma (MM). Apart from its role in homing, CXCR4 also affects MM cell mobilization and egression out of the bone marrow (BM) which is correlated with distant organ metastasis. Aberrant CXCR4 expression pattern is associated with osteoclastogenesis and tumor growth in MM through its cross talk with various important cell signalling pathways. A deeper insight into understanding of CXCR4 mediated signalling pathways and its role in MM is essential to identify potential therapeutic interventions. The current therapeutic focus is on disrupting the interaction of MM cells with its protective tumor microenvironment where CXCR4 axis plays an essential role. There are still multiple challenges that need to be overcome to target CXCR4 axis more efficiently and to identify novel combination therapies with existing strategies. This review highlights the role of CXCR4 along with its significant interacting partners as a mediator of MM pathogenesis and summarizes the targeted therapies carried out so far.

CD164 regulates proliferation, progression, and invasion of human glioblastoma cells

Grade IV astrocytoma, also known as glioblastoma multiforme (GBM), is the most common and aggressive intracranial glial tumor. GBM is associated with very poor survival and effective treatments have remained elusive so far. Mounting evidence indicates that CD164 contributes to stemness and tumorigenesis in normal cells and is overexpressed in various tumor types, including glioblastoma. Using tissue microarray immunohistochemistry, we show that there is a significant correlation between CD164 expression and glioma type and grade. Depletion of CD164 expression in human glioblastoma cells with siRNA reduced proliferation, migration, and invasiveness. In parallel, immunoblotting showed that downregulation of CD164 expression decreased Akt activation and modified the expression of autophagy markers by upregulating Beclin-1 and LC3B and downregulating p62. These effects were mimicked by inhibition of Akt with MK2206, which suggests that CD164 induces autophagy via Akt/Beclin-1 signaling. We propose that CD164 may serve as a GBM molecular marker and a potential target in therapeutic strategies aimed to improve outcomes for this devastating brain tumor.

Effect of integrin α5β1 inhibition on SDF-l/CXCR4-mediated choroidal neovascularization

AIM

To investigate the roles of integrins in choroidal neovascularization (CNV) and their associations with the stromal cell-derived factor-1 (SDF-1)/CXCR4 axis.

METHODS

CNV lesions were induced in mice using laser photocoagulation. After CNV induction, all animals were randomly assigned to: control, SDF-1, SDF-1+age-related macular degeneration (AMD) 3100 (CXCR4 inhibitor), and SDF-1+ATN161 (integrin α5β1 inhibitor) groups; their effects on CNV progression were observed using hematoxylin eosin (HE) staining, fundus fluorescein angiography (FFA) grading and optical coherence tomography (OCT), and their effects on CXCR4/integrin α5 expression were evaluated using Western blot and double immunofluorescence staining. Hypoxia-exposed endothelial cells (ECs) were used to simulate CNV in vitro, they were treated with SDF-1, combined with CXCR4 siRNA/AMD3100 or ATN161, and expression of integrin α5, cell migration and tube formation were analyzed.

RESULTS

Integrin subunit α5 increased at 3^rd and 7^th day and decreased at 14^th day in CNV mice, with no significant change of β1-integrin. CXCR4 expression in CNV mice had persistent increase within 14d after induction. SDF-1 treatment significantly promoted the CNV progression during 3-14d. The mean CNV length in AMD3100 and ATN161 group at day 7 was 270.13 and 264.23 µm in HE images, significantly lower than the mean length in SDF-1 (345.70 µm) group. AMD3100 and ATN161 also significantly reduced thickness and leakage of CNV induced by SDF-1. Mean integrin α5 positive area in SDF-1 group reached 2.31×104 µm², significantly higher than control (1.25×104 µm²), which decreased to 1.78×104 µm² after AMD3100 treatment. About 61.36% of ECs in CNV lesions expressed α5 in SDF-1 group, which significantly decreased to 43.12% after AMD3100 treatment. In vitro, integrin α5 peaked by 6 folds after 6h of hypoxia exposure and CXCR4 gradually increased by up to 2.3 folds after 24h of hypoxia. Approximately 25.12% of ECs expressed integrin α5 after SDF-1 stimulation, which decreased to 7.2%-9.5% after si-CXCR4 or AMD3100 treatment. ATN161 exerted an inhibitory effect comparable to that of si-CXCR4 on EC migration and tube formation in the presence of SDF-1.

CONCLUSION

SDF-1/CXCR4 signaling induces integrin α5β1 expression in ECs to promote CNV.