Oncogenic roles and drug target of CXCR4/CXCL12 axis in lung cancer and cancer stem cell

Beyond binary: bridging neutrophil diversity to new therapeutic approaches in NSCLC

Neutrophils represent the most abundant myeloid cell subtype in the non-small-cell lung cancer (NSCLC) tumor microenvironment (TME). By anti- or protumor polarization, they impact multiple aspects of tumor biology and affect sensitivity to conventional therapies and immunotherapies. Single-cell RNA sequencing (scRNA-seq) analyses have unraveled an extensive neutrophil heterogeneity, helping our understanding of their pleiotropic role. In this review we summarize recent data and models on tumor-associated neutrophil (TAN) biology, focusing on the diversity that evolves in response to tumor-intrinsic cues. We categorize available transcriptomic profiles from different cancer entities into a defined set of neutrophil subclusters with distinct phenotypic properties, to step beyond the traditional binary N1/2 classification. Finally, we discuss potential ways to exploit these neutrophil states in the setting of anticancer therapy.

CRISPR-mediated reversion of oncogenic KRAS mutation results in increased proliferation and reveals independent roles of Ras and mTORC2 in the migration of A549 lung cancer cells

Although the RAS oncogene has been extensively studied, new aspects concerning its role and regulation in normal biology and cancer continue to be discovered. Recently, others and we have shown that the mechanistic Target of Rapamycin Complex 2 (mTORC2) is a Ras effector in Dictyostelium and mammalian cells. mTORC2 plays evolutionarily conserved roles in cell survival and migration and has been linked to tumorigenesis. Because RAS is often mutated in lung cancer, we investigated whether a Ras-mTORC2 pathway contributes to enhancing the migration of lung cancer cells expressing oncogenic Ras. We used A549 cells and CRISPR/Cas9 to revert the cells' KRAS G12S mutation to wild-type and establish A549 revertant (REV) cell lines, which we then used to evaluate the Ras-mediated regulation of mTORC2 and cell migration. Interestingly, our results suggest that K-Ras and mTORC2 promote A549 cell migration but as part of different pathways and independently of Ras's mutational status. Moreover, further characterization of the A549REV cells revealed that loss of mutant K-Ras expression for the wild-type protein leads to an increase in cell growth and proliferation, suggesting that the A549 cells have low KRAS-mutant dependency and that recovering expression of wild-type K-Ras protein increases these cells tumorigenic potential.

Regeneration and anti-inflammatory effects of stem cells and their extracellular vesicles in gynecological diseases

There are many gynecological diseases, among which breast cancer (BC), cervical cancer (CC), endometriosis (EMs), and polycystic ovary syndrome (PCOS) are common and difficult to cure. Stem cells (SCs) are a focus of regenerative medicine. They are commonly used to treat organ damage and difficult diseases because of their potential for self-renewal and multidirectional differentiation. SCs are also commonly used for difficult-to-treat gynecological diseases because of their strong directional differentiation ability with unlimited possibilities, their tendency to adhere to the diseased tissue site, and their use as carriers for drug delivery. SCs can produce exosomes in a paracrine manner. Exosomes can be produced in large quantities and have the advantage of easy storage. Their safety and efficacy are superior to those of SCs, which have considerable potential in gynecological treatment, such as inhibiting endometrial senescence, promoting vascular reconstruction, and improving anti-inflammatory and immune functions. In this paper, we review the mechanisms of the regenerative and anti-inflammatory capacity of SCs and exosomes in incurable gynecological diseases and the current progress in their application in genetic engineering to provide a foundation for further research.

A review on immunological aspects in male reproduction: An immune cells and cytokines

The male reproductive system, particularly the male gamete, offers a unique barrier to the immune system. The growing germ cells in the testis need to be shielded from autoimmune damage. Hence the testis has to establish and sustain an immune-privileged milieu. Sertoli cells create this safe space, protected by the blood-testis barrier. Cytokines are a type of immune reaction that can positively and negatively affect male reproductive health. Inflammation, disease, and obesity are just a few physiological conditions for which cytokines mediate signals. They interact with steroidogenesis, shaping the adrenals and testes to produce the hormones needed for survival. In particular pathological condition, including autoimmune disorders, contains high levels of the same cytokines in semen that play an essential role in the immunomodulation of the male gonad. This review focuses on understanding the immunological role of cytokines in the control and development of male reproduction. Also, in maintaining male reproductive health and diseases linked with their aberrant function in the testis.

The role of CXCL family members in different diseases

Chemokines are a large family mediating a lot of biological behaviors including chemotaxis, tumor growth, angiogenesis and so on. As one member of this family, CXC subfamily possesses the same ability. CXC chemokines can recruit and migrate different categories of immune cells, regulate tumor's pathological behaviors like proliferation, invasion and metastasis, activate angiogenesis, etc. Due to these characteristics, CXCL subfamily is extensively and closely associated with tumors and inflammatory diseases. As studies are becoming more and more intensive, CXCLs' concrete roles are better described, and CXCLs' therapeutic applications including biomarkers and targets are also deeply explained. In this review, the role of CXCL family members in various diseases is summarized.

The road of NSCLC stem cells toward bone metastases

Despite advancement in therapeutic options, Non-Small Cell lung cancer (NSCLC) remains a lethal disease mostly due to late diagnosis at metastatic phase and drug resistance. Bone is one of the more frequent sites for NSCLC metastatization. A defined subset of cancer stem cells (CSCs) that possess motile properties, mesenchymal features and tumor initiation potential are defined as metastasis initiating cells (MICs). A better understanding of the mechanisms supporting MIC dissemination and interaction with bone microenvironment is fundamental to design novel rational therapeutic option for long lasting efficient treatment of NSCLC. In this review we will summarize findings about bone metastatic process initiated by NSCLC MICs. We will review how MICs can reach bone and interact with its microenvironment that supports their extravasation, seeding, dormancy/proliferation. The role of different cell types inside the bone metastatic niche, such as endothelial cells, bone cells, hematopoietic stem cells and immune cells will be discussed in regards of their impact in dictating the success of metastasis establishment by MICs. Finally, novel therapeutic options to target NSCLC MIC-induced bone metastases, increasing the survival of patients, will be presented.

MSX-122: Is an effective small molecule CXCR4 antagonist in cancer therapy?

Chemokines, a subgroup of cytokines along with their receptors, are involved in various biologic processes and regulation of a wide range of immune responses in different physiologic and pathologic states such as tissue repair, infection, and inflammation. C-X-C motif chemokine receptor 4 (CXCR4), a G-protein-coupled receptor (GPCR), has one identified natural ligand termed stromal-derived factor-1(SDF-1 or CXCL12). Evidence demonstrated that the ligation of SDF-1 to CXCR4 initiates several intracellular signaling pathways, regulating cell proliferation, survival, chemotaxis, migration, angiogenesis, adhesion, as well as bone marrow (BM)-resident cells homing and mobilization. Additionally, CXCR4 is expressed by tumor cells in blood malignancies and solid tumors. Therefore, CXCR4 is considered a potential therapeutic target in cancer therapy, and CXCR4 antagonists, including AMD3100, MSX-122, BPRCX807, WZ811, Motixafortide, TN14003, AMD3465, and AMD1170, have been employed in experimental and clinical studies to enhance cancer therapy. MSX-122 is a specific small-molecule antagonist of CXCR4/CXCL12 and the only orally available non-peptide CXCR4 antagonist with promising anti-cancer properties. Studies have shown that MSX-122 is particularly important in treating metastatic cancers and has great therapeutic potential. Accordingly, this review summarized the characteristics of MSX-122 and its effects on the CXCL12/CXCR4 axis as well as cancer therapy.

Serum Levels of Stromal Cell-Derived Factor-1α and Vascular Endothelial Growth Factor Predict Clinical Outcomes in Head and Neck Squamous Cell Carcinoma Patients Receiving TPF Induction Chemotherapy

Chemokines, such as stromal cell-derived factor-1α (SDF-1α) and vascular endothelial growth factor (VEGF), are associated with clinical outcomes in several cancer types. This study aimed to investigate the role of SDF-1α and VEGF in the prognosis of patients with head and neck squamous cell carcinoma (HNSCC) who underwent TPF induction chemotherapy (docetaxel, cisplatin, and 5-fluorouracil). A total of 77 HNSCC patients were enrolled and circulating SDF-1α and VEGF values were examined at two time points for each patient, including pre-TPF treatment (treatment-naïve) and post-TPF treatment but before chemoradiotherapy. The median progression-free survival (PFS) and overall survival (OS) were 18.1 and 32.9 months, respectively. Decreased SDF-1α and VEGF levels after TPF treatment, post-TPF SDF-1α < 1500 pg/mL and VEGF value < 150 pg/mL were independent prognostic factors for better PFS and OS in univariate and multivariate analyses. A combination of SDF-1α and VEGF values may predict clinical outcomes significantly. Our study confirmed the role of SDF-1α and VEGF in the disease progression of HNSCC, and that decreased SDF-1α and VEGF after TPF treatment and lower post-TPF SDF-1α and VEGF values were associated with better prognosis in HNSCC patients who received induction chemotherapy with TPF followed by chemoradiotherapy.

Predictive and Prognostic Biomarkers for Lung Cancer Bone Metastasis and Their Therapeutic Value

Lung cancer is the leading cause of cancer-related death worldwide. Bone metastasis, which usually accompanies severe skeletal-related events, is the most common site for tumor distant dissemination and detected in more than one-third of patients with advanced lung cancer. Biopsy and imaging play critical roles in the diagnosis of bone metastasis; however, these approaches are characterized by evident limitations. Recently, studies regarding potential biomarkers in the serum, urine, and tumor tissue, were performed to predict the bone metastases and prognosis in patients with lung cancer. In this review, we summarize the findings of recent clinical research studies on biomarkers detected in samples obtained from patients with lung cancer bone metastasis. These markers include the following: (1) bone resorption-associated markers, such as N-terminal telopeptide (NTx)/C-terminal telopeptide (CTx), C-terminal telopeptide of type I collagen (CTx-I), tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), pyridinoline (PYD), and parathyroid hormone related peptide (PTHrP); (2) bone formation-associated markers, including total serum alkaline phosphatase (ALP)/bone specific alkaline phosphatase(BAP), osteopontin (OP), osteocalcin (OS), amino-terminal extension propeptide of type I procollagen/carboxy-terminal extension propeptide of type I procollagen (PICP/PINP); (3) signaling markers, including epidermal growth factor receptor/Kirsten rat sarcoma/anaplastic lymphoma kinase (EGFR/KRAS/ALK), receptor activator of nuclear factor κB ligand/receptor activator of nuclear factor κB/osteoprotegerin (RANKL/RANK/OPG), C-X-C motif chemokine ligand 12/C-X-C motif chemokine receptor 4 (CXCL12/CXCR4), complement component 5a receptor (C5AR); and (4) other potential markers, such as calcium sensing receptor (CASR), bone sialoprotein (BSP), bone morphogenetic protein 2 (BMP2), cytokeratin 19 fragment/carcinoembryonic antigen (CYFRA/CEA), tissue factor, cell-free DNA, long non-coding RNA, and microRNA. The prognostic value of these markers is also investigated. Furthermore, we listed some clinical trials targeting hotspot biomarkers in advanced lung cancer referring for their therapeutic effects.

Regulatory roles of phytochemicals on circular RNAs in cancer and other chronic diseases

As novel non-coding RNAs (ncRNAs), circular RNAs (circRNAs) play an essential role in the pathogenesis of many chronic diseases, and the regulation of these functional molecules has become a research hotspot gradually. Within the past decade, phytochemicals were reported to regulate the expression of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in various chronic diseases, and more recently, most studies focus on the regulatory roles of phytochemicals on circRNAs. Abnormal expression of circRNAs has been identified in chronic diseases like cancer, heart failure, depression and atherosclerosis, and numerous studies have revealed the modulation of circRNAs by phytochemicals including berberine, celastrol, cinnamaldehyde, curcumin, et al. The expression of circRNAs, such as circSATB2 and circFOXM1, were modulated by phytochemicals, and these regulations further affected cell proliferation, apoptosis, migration, invasion, autophagy, chemosensitivity, radiosensitivity and other biological processes. Mechanismly, the circRNAs mainly functioned as miRNA sponge, subsequently affecting miRNA-mediated regulation of target genes and related cell signaling pathways. In this review, we summarized the impact of phytochemicals on circRNAs expression and biological function, and discussed the mechanisms underlying phytochemicals regulating circRNAs in cancer and other chronic diseases.

The Embryonic Key Pluripotent Factor NANOG Mediates Glioblastoma Cell Migration via the SDF1/CXCR4 Pathway

NANOG is a key transcription factor required for maintaining pluripotency of embryonic stem cells. Elevated NANOG expression levels have been reported in many types of human cancers, including lung, oral, prostate, stomach, breast, and brain. Several studies reported the correlation between NANOG expression and tumor metastasis, revealing itself as a powerful biomarker of poor prognosis. However, how NANOG regulates tumor progression is still not known. We previously showed in medaka fish that Nanog regulates primordial germ cell migration through Cxcr4b, a chemokine receptor known for its ability to promote migration and metastasis in human cancers. Therefore, we investigated the role of human NANOG in CXCR4-mediated cancer cell migration. Of note, we found that NANOG regulatory elements in the CXCR4 promoter are functionally conserved in medaka fish and humans, suggesting an evolutionary conserved regulatory axis. Moreover, CXCR4 expression requires NANOG in human glioblastoma cells. In addition, transwell assays demonstrated that NANOG regulates cancer cell migration through the SDF1/CXCR4 pathway. Altogether, our results uncover NANOG-CXCR4 as a novel pathway controlling cellular migration and support Nanog as a potential therapeutic target in the treatment of Nanog-dependent tumor progression.

Lidocaine inhibited migration of NSCLCA549 cells via the CXCR4 regulation

BACKGROUND:

Lidocaine is a local anesthetic that wildly used in surgical treatment and postoperative medical care for lung cancers. We hypothesized that lidocaine at clinical plasma concentration can inhibit CXCL12/CXCR4 axis-regulated cytoskeletal remodeling thereby reduce the migration of Non-small-cell lung cancers (NSCLC) cells.

METHODS:

We determined the effect of lidocaine at clinical plasma concentration on CXCL12-induced cell viability, apoptosis, cell death, monolayer cell wound healing rate, individual cell migration indicators, expression of CXCR4, CD44, and ICAM-1, intracellular Ca2+ level, and filamentous actin level alteration of NSCLC cells A549 and CXCR4-knocked down A549 cells using CCK-8, Bcl-2 ELISA, Cell death ELISA, wound healing assay, chemotaxis assay, western blotting, QPCR, Fura-2-based intracellular Ca2+ assay, and Fluorescein Phalloidin staining respectively.

RESULTS:

Lidocaine did not affect cell viability, apoptosis, and cell death but inhibited CXCL12-induced migration, intracellular Ca2+ releasing, and filamentous actin increase. Lidocaine decreased expression of CXCR4, increased CD44, but had no effect on ICAM-1. CXCL12 induced the increase of CD44 and ICAM-1 but did not affect CD44 in the presence of lidocaine. The knockdown of CXCR4 eliminated all the effects of lidocaine. The overexpression of CXCR4 promoted migration but the migration was inhibited by lidocaine.

CONCLUSION:

Lidocaine at clinical plasma concentrations inhibited CXCL12-induced CXCR4 activation, thereby reduced the intracellular Ca2+-dependent cytoskeleton remodeling, resulting in slower migration of A549 cells.

The CXCL12 Crossroads in Cancer Stem Cells and Their Niche

Simple Summary

CXCL12 and its receptors have been extensively studied in cancer, including their influence on cancer stem cells (CSCs) and their niche. This intensive research has led to a better understanding of the crosstalk between CXCL12 and CSCs, which has aided in designing several drugs that are currently being tested in clinical trials. However, a comprehensive review has not been published to date. The aim of this review is to provide an overview on how CXCL12 axes are involved in the regulation and maintenance of CSCs, their presence and influence at different cellular levels within the CSC niche, and the current state-of-the-art of therapeutic approaches aimed to target the CXCL12 crossroads.

Abstract

Cancer stem cells (CSCs) are defined as a subpopulation of “stem”-like cells within the tumor with unique characteristics that allow them to maintain tumor growth, escape standard anti-tumor therapies and drive subsequent repopulation of the tumor. This is the result of their intrinsic “stem”-like features and the strong driving influence of the CSC niche, a subcompartment within the tumor microenvironment that includes a diverse group of cells focused on maintaining and supporting the CSC. CXCL12 is a chemokine that plays a crucial role in hematopoietic stem cell support and has been extensively reported to be involved in several cancer-related processes. In this review, we will provide the latest evidence about the interactions between CSC niche-derived CXCL12 and its receptors—CXCR4 and CXCR7—present on CSC populations across different tumor entities. The interactions facilitated by CXCL12/CXCR4/CXCR7 axes seem to be strongly linked to CSC “stem”-like features, tumor progression, and metastasis promotion. Altogether, this suggests a role for CXCL12 and its receptors in the maintenance of CSCs and the components of their niche. Moreover, we will also provide an update of the therapeutic options being currently tested to disrupt the CXCL12 axes in order to target, directly or indirectly, the CSC subpopulation.

CXCR4 uses STAT3-mediated slug expression to maintain radioresistance of non-small cell lung cancer cells: emerges as a potential prognostic biomarker for lung cancer

Lung cancer is one of the most common reasons for cancer-induced mortality across the globe, despite major advancements in the treatment strategies including radiotherapy and chemotherapy. Existing reports suggest that CXCR4 is frequently expressed by malignant tumor and is imperative for vascularization, tumor growth, cell migration, and metastasis pertaining to poor prognosis. In this study, we infer that CXCR4 confers resistance to ionizing radiation (IR) in nonsmall cell lung cancer (NSCLC) cells. Further, on the basis of colony forming ability, one finds that drug-resistant A549/GR cells with improved CXCR4 expression exhibited more resistance to IR than A549 cells evidenced along with a reduction in the formation of γ-H2AX foci after IR. Transfection of shRNA against CXCR4 or treatment of pharmacological inhibitor (AMD3100) both led to sensitization of A549/GR cells towards IR. Conversely, the overexpression of CXCR4 in A549 and H460 cell lines was found to improve clonogenic survival, and reduce the formation of γ-H2AX foci after IR. CXCR4 expression was further correlated with STAT3 activation, and suppression of STAT3 activity with siSTAT3 or a specific inhibitor (WP1066) significantly stymied the colony-forming ability and increased γ-H2AX foci formation in A549/GR cells, indicating that CXCR4-mediated STAT3 signaling plays an important role for IR resistance in NSCLC cells. Finally, CXCR4/STAT3 signaling was mediated with the upregulation of Slug and downregulation of the same with siRNA, which heightened IR sensitivity in NSCLC cells. Our data collectively suggests that CXCR4/STAT3/Slug axis is paramount for IR resistance of NSCLC cells, and can be regarded as a therapeutic target to enhance the IR sensitivity of this devastating cancer.

KRT6A Promotes EMT and Cancer Stem Cell Transformation in Lung Adenocarcinoma

Aim:

Keratin 6A is a type II cytokeratin which is important in forming nail bed, filiform papillae, the epithelial lining of oral mucosa, and esophagus; recently, keratin 6A was found hyperexpressed in different types of cancer. But, the biological function of keratin 6A in lung adenocarcinoma still remains unclear. Therefore, in current study, we investigated the biological role of keratin 6A in lung adenocarcinoma.

Methods:

By utilizing The Cancer Genome Atlas database, we investigated the expression profile of keratin 6A and its relationship with other clinical parameters in lung adenocarcinoma. The biological function of keratin 6A in lung adenocarcinoma was also investigated by using A549 and PC-9 lung cancer cell lines in vitro.

Results:

Our data indicate that, compared with normal lung tissue samples, keratin 6A was hyperexpressed in lung adenocarcinoma. Moreover, keratin 6A hyperexpression was positively correlated with lymph node positive and aggressive tumor T stage. Keratin 6A knockdown inhibited the cell proliferation, migration, and colony formation ability but not cell death in lung adenocarcinoma cells. In addition, we found keratin 6A exerted its phenotype via promoting cancer stem cells (CXCR4^high/CD133^high) transformation and epithelial–mesenchymal transition.

Conclusion:

In conclusion, current study suggests that hyperexpressed keratin 6A in lung adenocarcinoma promotes lung cancer proliferation and metastasis via epithelial–mesenchymal transition and cancer stem cells transformation.

CXCL12-PLGA/Pluronic Nanoparticle Internalization Abrogates CXCR4-Mediated Cell Migration

Chemokine-induced chemotaxis mediates physiological and pathological immune cell trafficking, as well as several processes involving cell migration. Among them, the role of CXCL12/CXCR4 signaling in cancer and metastasis is well known, and CXCR4 has been often targeted with small molecule-antagonists or short CXCL12-derived peptides to limit the pathological processes of cell migration and invasion. To reduce CXCR4-mediated chemotaxis, we adopted a different approach. We manufactured poly(lactic acid-co-glycolic acid) (PLGA)/Pluronic F127 nanoparticles through microfluidics-assisted nanoprecipitation and functionalized them with streptavidin to docking a biotinylated CXCL12 to be exposed on the nanoparticle surface. Our results show that CXCL12-decorated nanoparticles are non-toxic and do not induce inflammatory cytokine release in THP-1 monocytes cultured in fetal bovine and human serum-supplemented media. The cell internalization of our chemokine receptor-targeting particles increases in accordance with CXCR4 expression in FBS/medium. We demonstrated that CXCL12-decorated nanoparticles do not induce cell migration on their own, but their pre-incubation with THP-1 significantly decreases CXCR4⁺-cell migration, thereby antagonizing the chemotactic action of CXCL12. The use of biodegradable and immune-compatible chemokine-mimetic nanoparticles to reduce cell migration opens the way to novel antagonists with potential application in cancer treatments and inflammation.

CXCR4 Inhibition Counteracts Immunosuppressive Properties of Metastatic NSCLC Stem Cells

Cancer stem cells (CSCs) are functionally defined as the cell subset with greater potential to initiate and propagate tumors. Within the heterogeneous population of lung CSCs, we previously identified highly disseminating CD133+CXCR4+ cells able to initiate distant metastasis (metastasis initiating cells-MICs) and to resist conventional chemotherapy. The establishment of an immunosuppressive microenvironment by tumor cells is crucial to sustain and foster metastasis formation, and CSCs deeply interfere with immune responses against tumors. How lung MICs can elude and educate immune cells surveillance to efficiently complete the metastasis cascade is, however, currently unknown. We show here in primary tumors from non-small cell lung cancer (NSCLC) patients that MICs express higher levels of immunoregulatory molecules compared to tumor bulk, namely PD-L1 and CD73, an ectoenzyme that catalyzes the production of immunosuppressive adenosine, suggesting an enhanced ability of MICs to escape immune responses. To investigate in vitro the immunosuppressive ability of MICs, we derived lung spheroids from cultures of adherent lung cancer cell lines, showing enrichment in CD133+CXCR4+MICs, and increased expression of CD73 and CD38, an enzyme that also concurs in adenosine production. MICs-enriched spheroids release high levels of adenosine and express the immunosuppressive cytokine IL-10, undetectable in an adherent cell counterpart. To prevent dissemination of MICs, we tested peptide R, a novel CXCR4 inhibitor that effectively controls in vitro lung tumor cell migration/invasion. Notably, we observed a decreased expression of CD73, CD38, and IL-10 following CXCR4 inhibition. We also functionally proved that conditioned medium from MICs-enriched spheroids compared to adherent cells has an enhanced ability to suppress CD8+ T cell activity, increase Treg population, and induce the polarization of tumor-associated macrophages (TAMs), which participate in suppression of T cells. Treatment of spheroids with anti-CXCR4 rescued T cell cytotoxic activity and prevented TAM polarization, likely by causing the decrease of adenosine and IL-10 production. Overall, we provide evidence that the subset of lung MICs shows high potential to escape immune control and that inhibition of CXCR4 can impair both MICs dissemination and their immunosuppressive activity, therefore potentially providing a novel therapeutic target in combination therapies to improve efficacy of NSCLC treatment.

Prognostic Value of SDF-1α Expression in Patients with Esophageal Squamous Cell Carcinoma Receiving Esophagectomy

Stromal cell-derived factor-1α (SDF-1α) is a chemokine that has been reported to be involved in tumor progression in several malignancies. This study aimed to evaluate the crucial role of SDF-1α in patients with esophageal squamous cell carcinoma (ESCC) who underwent esophagectomy. A total of 169 patients with ESCC were identified, including overexpression of SDF-1α in 60 patients and low expression of SDF-1α in 109 patients by immunohistochemical analysis. Two ESCC cell lines, TE1 and KYSE30, were selected to evaluate the tumor cell proliferative effect of SDF-1α. Univariate and multivariate analyses showed that high tumor (T) status, positive lymph node metastasis, tumors located in the upper esophagus, and SDF-1α overexpression were significantly related to worse disease-free survival and overall survival. In addition, the two cell lines were treated with SDF-1α, AMD3100 (an SDF-1α-ligand receptor antagonist), and chemotherapeutic agents (cisplatin). Our in vitro study results showed that SDF-1α promoted the proliferation of tumor cells, and blocking the SDF-1α pathway displayed a growth inhibition effect in a dose-dependent manner. SDF-1α plays an important role in the progression of ESCC and is an independent prognostic factor for ESCC patients who underwent esophagectomy.

Non-coding RNA profile in lung cancer

Lung cancer is the most frequently diagnosed malignancy and the leading source of cancer-associated mortality. This kind of cancer has heterogeneous nature and is divided into two broad classes of small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). In addition to aberrant expression of several signaling pathways and oncogenes, lung cancer is associated with dysregulation of expression of non-coding RNAs including both long non-coding RNAs (lncRNAs) and miRNAs. These aberrantly expressed transcripts are putative therapeutic targets and diagnostic/ prognostic markers. Integrative assessment of expression of lncRNAs, miRNAs and mRNAs has led to construction of competing endogenous RNA networks in which several lncRNAs act as molecular sponges to inhibit regulatory function of miRNAs on mRNAs. Notably, some of these networks seem to have subtype-specific functions in lung cancer. In this review, we summarize recent findings about the importance of these networks in the pathogenesis of lung cancer and provide a list of onco-miRNAs, tumor suppressor miRNAs, oncogenic lncRNAs and tumor suppressor lncRNAs based on their roles in the carcinogenic process in lung cancer.

High CXCR4 expression in adenoid cystic carcinoma of the head and neck is associated with increased risk of locoregional recurrence

AIM

Treatment options for head and neck adenoid cystic carcinoma (AdCC) are limited in advanced disease. Chemokine receptor type 4 (CXCR4) is present in various tumour types, including AdCC. Upregulation is associated with tumour recurrence and metastasis. New CXCR4-specific diagnostic and therapeutic target agents have recently been available. This study aimed to analyse CXCR4 expression in a cohort of primary head and neck AdCC.

METHODS

After histopathological revision, tumour tissues of 73 consecutive patients with AdCC over 1990-2016 were sampled on a tissue microarray. Slides were immunohistochemically stained for CXCR4 and semiquantitatively scored. Associations between protein expression and cliniopathological parameters were tested. HRs were calculated using a Cox proportional hazard model.

RESULTS

Sixty-six tumours could be analysed. CXCR4 expression was present in 81% of the tumours with a median of 29% (IQR 1-70) positive cells. Expression was univariately correlated to perineural growth (Spearman ρ .26, p=0.04) and bone invasion (Spearman ρ .32, p=0.01), but not with tumour grade.CXCR4 expression in the primary tumour was significantly higher in tumours that recurred as compared with those that did not recur (median 60%, IQR 33-72 vs 12%, IQR 1-70, Kruskal-Wallis p=0.01). After dichotomisation, >25% of CXCR4 expressions proved an independent prognosticator for a reduced recurrence-free survival (RFS) (HR 7.2, 95% CI 1.5 to 72.4, p=0.04).

CONCLUSION

CXCR4 is expressed in the majority of primary AdCCs and independently correlated to worse RFS, suggesting CXCR4 as a target for imaging and therapy purposes in patients with advanced AdCC.

Spherical silica nanoparticles promote malignant transformation of BEAS-2B cells by stromal cell-derived factor-1α (SDF-1α)

Objective

This study aimed to examine the role of spherical silica nanoparticles (SiNPs) on human bronchial epithelial (BEAS-2B) cells through inflammation.

Methods

Human mononuclear (THP-1) cells and BEAS-2B cells were co-cultured in transwell chambers and treated with 800 mmol/L benzo[a]pyrene-7, 8-dihydrodiol-9, 10-epoxide (BPDE) and 12.5 µg/mL SiNPs for 24 hours. For controls, cells were treated with BPDE alone. Subcutaneous tumorigenicity and epithelial-mesenchymal transition (EMT) of BEAS-2B cells were measured. The cells were blocked with a stromal cell-derived factor-1α (SDF-1α)-specific antibody. EMT was analyzed in cells treated with 800 mmol/L BPDE and 12.5 µg/mL SiNPs relative to matched control cells and xenografts in vivo. Serum SDF-1α levels were measured in 23 patients with lung adenocarcinoma in Xuanwei, in 25 with lung adenocarcinoma outside Xuanwei, and in 22 with benign pulmonary lesions in Xuanwei.

Results

SiNPs significantly promoted tumorigenesis and EMT, induced the release of SDF-1α, and activated AKT (ser473) in BEAS-2B cells. EMT and phosphorylated AKT (ser473) and glycogen synthase kinase-3β levels were decreased when blocked by SDF-1α antibody in BEAS-2B cells. SDF-1α was mainly secreted by THP-1 cells.

Conclusion

SiNPs combined with BPDE promote EMT of BEAS-2B cells via the AKT pathway by inducing release of SDF-1α from THP-1 cells.

Targeting CXCL12/CXCR4 Axis in Tumor Immunotherapy

Chemokines, which have chemotactic abilities, are comprised of a family of small cytokines with 8-10 kilodaltons. Chemokines work in immune cells by trafficking and regulating cell proliferation, migration, activation, differentiation, and homing. CXCR-4 is an alpha-chemokine receptor specific for stromal-derived-factor-1 (SDF-1, also known as CXCL12), which has been found to be expressed in more than 23 different types of cancers. Recently, the SDF-1/CXCR-4 signaling pathway has emerged as a potential therapeutic target for human tumor because of its critical role in tumor initiation and progression by activating multiple signaling pathways, such as ERK1/2, ras, p38 MAPK, PLC/ MAPK, and SAPK/ JNK, as well as regulating cancer stem cells. CXCL12/CXCR4 antagonists have been produced, which have shown encouraging results in anti-cancer activity. Here, we provide a brief overview of the CXCL12/CXCR4 axis as a molecular target for cancer treatment. We also review the potential utility of targeting CXCL12/CXCR4 axis in combination of immunotherapy and/or chemotherapy based on up-to-date literature and ongoing research progress.

Chemotherapy and Inflammatory Cytokine Signalling in Cancer Cells and the Tumour Microenvironment

Cancer is the result of a cell's acquisition of a variety of biological capabilities or 'hallmarks' as outlined by Hanahan and Weinberg. These include sustained proliferative signalling, the ability to evade growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and the ability to invade other tissue and metastasize. More recently, the ability to escape immune destruction has been recognized as another important hallmark of tumours. It is suggested that genome instability and inflammation accelerates the acquisition of a variety of the above hallmarks. Inflammation, is a product of the body's response to tissue damage or pathogen invasion. It is required for tissue repair and host defense, but prolonged inflammation can often be the cause for disease. In a cancer patient, it is often unclear whether inflammation plays a protective or deleterious role in disease progression. Chemotherapy drugs can suppress tumour growth but also induce pathways in tumour cells that have been shown experimentally to support tumour progression or, in other cases, encourage an anti-tumour immune response. Thus, with the goal of better understanding the context under which each of these possible outcomes occurs, recent progress exploring chemotherapy-induced inflammatory cytokine production and the effects of cytokines on drug efficacy in the tumour microenvironment will be reviewed. The implications of chemotherapy on host and tumour cytokine pathways and their effect on the treatment of cancer patients will also be discussed.

Identification of an Unfavorable Immune Signature in Advanced Lung Tumors from Nrf2-Deficient Mice

AIMS

Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway in normal cells inhibits carcinogenesis, whereas constitutive activation of Nrf2 in cancer cells promotes tumor growth and chemoresistance. However, the effects of Nrf2 activation in immune cells during lung carcinogenesis are poorly defined and could either promote or inhibit cancer growth. Our studies were designed to evaluate tumor burden and identify immune cell populations in the lungs of Nrf2 knockout (KO) versus wild-type (WT) mice challenged with vinyl carbamate.

RESULTS

Nrf2 KO mice developed lung tumors earlier than the WT mice and exhibited more and larger tumors over time, even at late stages. T cell populations were lower in the lungs of Nrf2 KO mice, whereas tumor-promoting macrophages and myeloid-derived suppressor cells were elevated in the lungs and spleen, respectively, of Nrf2 KO mice relative to WT mice. Moreover, 34 immune response genes were significantly upregulated in tumors from Nrf2 KO mice, especially a series of cytokines (Cxcl1, Csf1, Ccl9, Cxcl12, etc.) and major histocompatibility complex antigens that promote tumor growth.

INNOVATION

Our studies discovered a novel immune signature, characterized by the infiltration of tumor-promoting immune cells, elevated cytokines, and increased expression of immune response genes in the lungs and tumors of Nrf2 KO mice. A complementary profile was also found in lung cancer patients, supporting the clinical significance of our findings.

CONCLUSION

Overall, our results confirmed a protective role for Nrf2 in late-stage carcinogenesis and, unexpectedly, suggest that activation of Nrf2 in immune cells may be advantageous for preventing or treating lung cancer. Antioxid. Redox Signal.

Melatonin disturbs SUMOylation-mediated crosstalk between c-Myc and nestin via MT1 activation and promotes the sensitivity of paclitaxel in brain cancer stem cells

Here the underlying antitumor mechanism of melatonin and its potency as a sensitizer of paclitaxel was investigated in X02 cancer stem cells. Melatonin suppressed sphere formation and induced G2/M arrest in X02 cells expressing nestin, CD133, CXCR4, and SOX-2 as biomarkers of stemness. Furthermore, melatonin reduced the expression of CDK2, CDK4, cyclin D1, cyclin E, and c-Myc and upregulated cyclin B1 in X02 cells. Notably, genes of c-Myc related mRNAs were differentially expressed in melatonin-treated X02 cells by microarray analysis. Consistently, melatonin reduced the expression of c-Myc at mRNA and protein levels, which was blocked by MG132. Of note, overexpression of c-Myc increased the expression of nestin, while overexpression of nestin enhanced c-Myc through crosstalk despite different locations, nucleus, and cytoplasm. Interestingly, melatonin attenuated small ubiquitin-related modifier-1 (SUMO-1) more than SUMO-2 or SUMO-3 and disturbed nuclear translocation of nestin for direct binding to c-Myc by SUMOylation of SUMO-1 protein by immunofluorescence and immunoprecipitation. Also, melatonin reduced trimethylated histone H3K4me3 and H3K36me3 more than dimethylation in X02 cells by Western blotting and chromatin immunoprecipitation assay. Notably, melatonin upregulated MT1, not MT2, in X02 cells and melatonin receptor inhibitor luzindole blocked the ability of melatonin to decrease the expression of nestin, p-c-Myc(S62), and c-Myc. Furthermore, melatonin promoted cytotoxicity, sub-G1 accumulation, and apoptotic body formation by Paclitaxcel in X02 cells. Taken together, these findings suggest that melatonin inhibits stemness via suppression of c-Myc, nestin, and histone methylation via MT1 activation and promotes anticancer effect of Paclitaxcel in brain cancer stem cells.

Hesperidin suppresses the migration and invasion of non-small cell lung cancer cells by inhibiting the SDF-1/CXCR-4 pathway

OBJECTIVE

The present study aimed to investigate the ability of hesperidin to suppress the migration and invasion of A549 cells, and to investigate the role of the SDF-1/CXCR-4 cascade in this suppression.

METHODS

We performed a Transwell migration assay to measure the migratory capability of A549 cells treated with 0.5% DMSO, SDF-1α, AMD3100 or hesperidin. The SDF-1 level in the culture medium was determined by an enzyme-linked immunosorbent assay (ELISA) to detect whether different concentrations of hesperidin affected SDF-1 secretion. A wound-healing assay was performed to determine the effects of different concentrations of hesperidin on the migration inhibition of A549, H460 and H1975 cells. Additionally, the effect of various hesperidin concentrations on the rate of A549 cell invasion and migration was examined with and without Matrigel in Transwell assays, respectively. Western blot analysis was used to evaluate the protein levels of CXCR-4, MMP-9, CK-19, Vimentin, p65, p-p65, p-IκB, IκB, p-Akt and Akt. RT-qPCR was used to detect the mRNA levels of CXCR-4, MMP-9, CK-19, Vimentin, p65, IκB, SDF-1 and Akt.

RESULTS

The Transwell migration assay indicated that SDF-1α promoted A549 cell migration, while AMD3100 and hesperidin significantly inhibited the migratory capability. The wound-healing assay demonstrated that hesperidin treatment significantly reduced the rate of wound closure compared with the control group in a dose-dependent manner. Similarly, the migration and invasive abilities of A549 cells, H460 and H1975 cells treated with hesperidin were significantly decreased compared with the control group. The ELISA data suggested that hesperidin attenuated the secretion of SDF-1 from A549 cells in a dose-dependent manner. Furthermore, western blot analysis indicated that SDF-1α treatment significantly increased the levels of CXCR-4, p-p65, p-IκB and p-Akt in A549 cells. In contrast, AMD3100 or hesperidin reversed the effect induced by SDF-1α through decreasing the expression of CXCR-4. Subsequent RT-qPCR and western blot analyses also confirmed that hesperidin had a significant effect on the expression of EMT-related proteins, including MMP-9, CK-19 and Vimentin, in A549 cells.

CONCLUSION

In summary, we demonstrated that hesperidin inhibited the migratory and invasive capabilities of A549 human non-small cell lung cancer cells by the mediation of the SDF-1/CXCR-4 signaling cascade, thus providing the foundation for the development of hesperidin as a safer and more effective anticancer drug for non-small cell lung cancer.

UNBS5162 inhibits proliferation of human retinoblastoma cells by promoting cell apoptosis

Human retinoblastomas are malignant intraocular tumors and have a high incidence in children. Chemotherapy combined with local therapy is the principal means of retinoblastoma treatment, the application of which has saved the eye of many children and avoided external irradiation. UNBS5162, a naphthalimide, has broad prospects as a tumor treatment, with fewer toxic side effects and higher cancer-suppression efficiency. However, the efficacy of UNBS5162 in human retinoblastomas is still not clear. In the present study, we investigated the specific mechanism of UNBS5162 in the human retinoblastoma cell lines WERIRb1 and Y79. Compared with a negative-control (NC) group, UNBS5162 treatment for 72 hours significantly decreased cell proliferation; meanwhile, more apoptotic cells were observed in the UNBS5162-treated group (27.1% in WERIRb1, 20.83% in Y79) than in the NC group (11.59% in WERIRb1, 12.89% in Y79). We also found caspase 3 p17 and Bax expression to be upregulated and Bcl2 downregulated significantly in UNBS5162-treated WERIRb1 and Y79 cells. The effects of UNBS5162 on human retinoblastoma cells may be regulated by the Akt–mTOR pathway. We found expression of the Akt pathway and key proliferation-related genes – those for p-Akt, p-mTOR, p70, and cyclin D₁ – were downregulated significantly in the UNBS5162-treated group compared with the NC group in WERIRb1 and Y79. Therefore, for the first time, we demonstrated that UNBS5162 can inhibit proliferation and promote apoptosis of human retinoblastoma cells by regulating activity of the Akt–mTOR pathway in vitro, suggesting the potential value of UNBS5162 in treatment for human retinoblastoma.

The role of hypoxia on the acquisition of epithelial-mesenchymal transition and cancer stemness: a possible link to epigenetic regulation

A hypoxic microenvironment leads to cancer progression and increases the metastatic potential of cancer cells within tumors via epithelial-mesenchymal transition (EMT) and cancer stemness acquisition. The hypoxic response pathway can occur under oxygen tensions of < 40 mmHg through hypoxia-inducible factors (HIFs), which are considered key mediators in the adaptation to hypoxia. Previous studies have shown that cellular responses to hypoxia are required for EMT and cancer stemness maintenance through HIF-1α and HIF-2α. The principal transcription factors of EMT include Twist, Snail, Slug, Sip1 (Smad interacting protein 1), and ZEB1 (zinc finger E-box-binding homeobox 1). HIFs bind to hypoxia response elements within the promoter region of these genes and also target cancer stem cell-associated genes and mediate transcriptional responses to hypoxia during stem cell differentiation. Acquisition of stemness characteristics in epithelial cells can be induced by activation of the EMT process. The mechanism of these phenotypic changes includes epigenetic alterations, such as DNA methylation, histone modification, chromatin remodeling, and microRNAs. Increased expression of EMT and pluripotent genes also play a role through demethylation of their promoters. In this review, we summarize the role of hypoxia on the acquisition of EMT and cancer stemness and the possible association with epigenetic regulation, as well as their therapeutic applications.

Tumor-Associated Macrophages as Target for Antitumor Therapy

It is well known that the microenvironment of solid tumors is rich in inflammatory cells that influence tumor growth and development. Macrophages, called tumor-associated macrophages (TAMs), are the most abundant immune cell population present in tumor tissue. Several studies have demonstrated that the density of TAMs is associated with a poor prognosis and positively correlates with tumor growth. Several studies have proved that TAMs may activate and protect tumor stem cells, stimulate their proliferation as well as promote angiogenesis and metastasis. Furthermore, TAMs-derived cytokines and other proteins, such as CCL-17, CCL-22, TGF-β, IL-10, arginase 1, and galectin-3, make a significant contribution to immunosuppression. Since TAMs influence various aspects of cancer progression, there are many attempts to use them as a target for immunotherapy. The numerous studies have shown that the primary tumor growth and the number of metastatic sites can be significantly decreased by decreasing the population of macrophages in tumor tissue, for example, by blocking recruitment of monocytes or eliminating TAMs already present in the tumor tissue. Moreover, there are attempts at reprogramming TAMs into proinflammatory M1 macrophages or neutralizing the protumoral products of TAMs. Another approach uses TAMs for anticancer drug delivery into the tumor environment. In this review, we would like to summarize the clinical and preclinical trials that were focused on macrophages as a target for anticancer therapies.

Comparison of tumor biology of two distinct cell sub-populations in lung cancer stem cells

Characterization of the stem-like properties of cancer stem cells (CSCs) remain indirect and qualitative, especially the ability of CSCs to undergo asymmetric cell division for self renewal and differentiation, a unique property of cells of stem origin. It is partly due to the lack of stable cellular models of CSCs. In this study, we developed a new approach for CSC isolation and purification to derive a CSC-enriched cell line (LLC-SE). By conducting five consecutive rounds of single cell cloning using the LLC-SE cell line, we obtained two distinct sub-population of cells within the Lewis lung cancer CSCs that employed largely symmetric division for self-renewal (LLC-SD) or underwent asymmetric division for differentiation (LLC-ASD). LLC-SD and LLC-ASD cell lines could be stably passaged in culture and be distinguished by cell morphology, stem cell marker, spheroid formation and subcutaneous tumor initiation efficiency, as well as orthotopic lung tumor growth, progression and survival. The ability LLC-ASD cells to undergo asymmetric division was visualized and quantified by the asymmetric segregation of labeled BrdU and NUMB to one of the two daughter cells in anaphase cell division. The more stem-like LLC-SD cells exhibited higher capacity for tumorigenesis and progression and shorter survival. As few as 10 LLC-SD could initiate subcutaneous tumor growth when transplanted to the athymic mice. Collectively, these observations suggest that the SD-type of cells appear to be on the top of the hierarchical order of the CSCs. Furthermore, they have lead to generated cellular models of CSC self-renewal for future mechanistic investigations.

Stemness-Related Markers in Cancer

Cancer stem cells (CSCs), with their self-renewal ability and multilineage differentiation potential, are a critical subpopulation of tumor cells that can drive tumor initiation, growth, and resistance to therapy. Like embryonic and adult stem cells, CSCs express markers that are not expressed in normal somatic cells and are thus thought to contribute towards a 'stemness' phenotype. This review summarizes the current knowledge of stemness-related markers in human cancers, with a particular focus on important transcription factors, protein surface markers and signaling pathways.

Synthesis of Peptide-Functionalized Poly(bis-sulfone) Copolymers Regulating HIV-1 Entry and Cancer Stem Cell Migration

Peptide-polymer conjugates have been regarded as primary stronghold in biohybrid nanomedicine, which has seen extensive development due to its intrinsic property to provide complementary functions of both the peptide material and the synthetic polymer platform. Here we present an advanced macromolecular therapeutic that targets two exclusive classes of important diseases (namely, the HIV and cancer) that are implicated by extremely different causative agents. Using a facile thiol-reactive monomer, the eventual polymer facilitates multivalent conjugation of an endogenous peptide WSC02 that targets the CXCR4 chemokine receptor. The biohybrid material demonstrated both potent antiviral effects against HIV-1 as well as inhibiting cancer stem cell migration thus establishing the foundation for multimodal nanotherapeutics that simultaneously target more than one class of disease implications.

Cytokines in Male Fertility and Reproductive Pathologies: Immunoregulation and Beyond

Germline development in vivo is dependent on the environment formed by somatic cells and the differentiation cues they provide; hence, the impact of local factors is highly relevant to the production of sperm. Knowledge of how somatic and germline cells interact is central to achieving biomedical goals relating to restoring, preserving or restricting fertility in humans. This review discusses the growing understanding of how cytokines contribute to testicular function and maintenance of male reproductive health, and to the pathologies associated with their abnormal activity in this organ. Here we consider both cytokines that signal through JAKs and are regulated by SOCS, and those utilizing other pathways, such as the MAP kinases and SMADs. The importance of cytokines in the establishment and maintenance of the testis as an immune-privilege site are described. Current research relating to the involvement of immune cells in testis development and disease is highlighted. This includes new data relating to testicular cancer which reinforce the understanding that tumorigenic cells shape their microenvironment through cytokine actions. Clinical implications in pathologies relating to local inflammation and to immunotherapies are discussed.

CXCR4 is involved in CD133-induced EMT in non-small cell lung cancer

Metastasis is the major cause of death in patients with non-small cell lung cancer (NSCLC), and epithelial-mesenchymal transition (EMT) has been observed to be one of the key regulators of metastasis in certain cancers as it confers an invasive phenotype. CD133 is a widely used cancer stem cell (CSC) marker, and CD133-positive cancer cells are thought to be tumor-initiating cells with CSC characteristics, while CXCR4, a stromal-derived-factor-1 specific chemokine receptor, is highly expressed in NSCLC tissues and participates in cancer progression by regulating cell anti-apoptosis. We previously demonstrated that CXCR4 promotes NSCLC chemoresistance by upregulating CYP1B1, however, the relationship of CD133, CXCR4 and EMT processes in NSCLC metastasis are unclear. In this study, we detected a CD133 and CXCR4 high expression in tissue specimens from 64 NSCLC patients by immunohistochemistry, of which CD133 and CXCR4 were found to be positively associated with metastatic NSCLC patients. CD133 was found to promote NSCLC tumorigenesis and mediated the expression of CXCR4. Furthermore, CD133/CXCR4 co-expression was found to be an independent prognostic factor as shown by univariate and multivariate Cox regression analysis, and was observed to regulate the expression of EMT-related molecules and transcriptional factors in NSCLC. In addition, our results showed that E-cadherin and Vimentin were simultaneously downregulated and upregulated, in CD133+CXCR4+ A549 cells, respectively. While E-cadherin was upregulated and Vimentin was downregulated in metastatic NSCLC patients. Vimentin expression was also observed to have a positive correlation with CD133/CXCR4 co-expression in NSCLC patients and survival analysis results suggested that Vimentin high expression might be significantly associated with poor survival rates of the patients. Thus, these results suggest that the CD133/CXCR4/EMT axis may be a prognostic marker and may provide novel targets for combinational therapies in the treatment of NSCLC.

CXCL7 promotes proliferation and invasion of cholangiocarcinoma cells

CXCL7 is an important chemoattractant cytokine, which signals through binding to its receptor CXCR2. Recent studies have demonstrated that the CXCL7/CXCR2 signaling plays a promoting role in several common malignancies, including lung, renal, colon, and breast cancer. However, the regulatory role of CXCL7, in cholangiocarcinoma, as well as the underlying mechanism, has not been previously reported. Herein, we found more positive expression of CXCL7 in cholangiocarcinoma tissues compared to adjacent non-tumor tissues. High CXCL7 expression was significantly correlated with poor differentiation, lymph node metastasis, vascular invasion and advanced clinical stage, but was not associated with age, gender, or tumor size. Besides, the expression of CXCL7 was significantly associated with the Ki67 expression, but not associated with CA199, AFP, or P53 expression in cholangiocarcinoma. Moreover, the overall survival of cholangiocarcinoma patients with high CXCL7 expression was significantly shorter than those with low CXCL7 expression. In vitro study indicated that CXCL7 and CXCR2 were also positively expressed in several common cholangiocarcinoma cell lines, including HuCCT1, HuH28, QBC939, EGI-1, OZ and WITT. SiRNA-induced inhibition of CXCL7 significantly reduced the proliferation and invasion of QBC939 cells. On the contrary, overexpression of CXCL7 markedly promoted these malignant phenotypes of QBC939 cells. Of note, the conditioned medium of CXCL7-overexpresing human hepatic stellate cells could also promote the proliferation and invasion of QBC939 cells, suggesting that CXCL7 may also play an oncogenic role in cholangiocarcinoma in a paracrine-dependent manner, not only in an autocrine-dependent manner. Molecular assay data suggested that the AKT signaling pathway was involved in the CXCL7-mediated malignant phenotypes of QBC939 cells. In summary, our study suggests that CXCL7 plays a promoting role in regulating the growth and metastasis of cholangiocarcinoma.

CXCL5 promotes the proliferation and migration of glioma cells in autocrine- and paracrine-dependent manners

CXCL5 and its receptor CXCR2 have been found to be involved in tumorigenesis and cancer progression. Recent studies have shown that CXCR2 is upregulated in glioma tissues, and associated with poor prognosis and recurrence. However, the role of CXCL5/CXCR2 signaling in mediating the malignant phenotypes of glioma cells, as well as the underlying mechanism, still remains unclear. In the present study, we found that CXCL5 was upregulated in glioma tissues compared to that noted in normal brain tissues. High CXCL5 levels were significantly associated with higher tumor grade, advanced clinical stage, and shorter survival time of glioma patients. In vitro studies indicated that the protein expression levels of CXCL5 and CXCR2 were markedly higher in human glioma cell lines (U87, U251, U373 and A172), when compared with those in normal human gliocyte HEB cells. Overexpression of CXLC5 significantly promoted the proliferation and migration of U87 cells, while knockdown of CXCL5 by small interfering RNA markedly inhibited U87 cell proliferation and migration. Moreover, both exogenous CXCL5 treatment and the conditioned medium of CXCL5-overexpressing HEB cells also enhanced the proliferation and migration of U87 cells. Molecular mechanism investigation revealed that CXLC5 activated the ERK, JNK, p38 MAPK signaling pathways, which play key roles in tumor growth and metastasis. According to these data, our study suggests that CXCL5 plays a promoting role in glioma in autocrine- and paracrine-dependent manners.