Blockade of CXCR6 reduces invasive potential of gastric cancer cells through inhibition of AKT signaling

The Role of CXCL16 in the Pathogenesis of Cancer and Other Diseases

CXCL16 is a chemotactic cytokine belonging to the α-chemokine subfamily. It plays a significant role in the progression of cancer, as well as the course of atherosclerosis, renal fibrosis, and non-alcoholic fatty liver disease (NAFLD). Since there has been no review paper discussing the importance of this chemokine in various diseases, we have collected all available knowledge about CXCL16 in this review. In the first part of the paper, we discuss background information about CXCL16 and its receptor, CXCR6. Next, we focus on the importance of CXCL16 in a variety of diseases, with an emphasis on cancer. We discuss the role of CXCL16 in tumor cell proliferation, migration, invasion, and metastasis. Next, we describe the role of CXCL16 in the tumor microenvironment, including involvement in angiogenesis, and its significance in tumor-associated cells (cancer associated fibroblasts (CAF), microglia, tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), mesenchymal stem cells (MSC), myeloid suppressor cells (MDSC), and regulatory T cells (T_reg)). Finally, we focus on the antitumor properties of CXCL16, which are mainly caused by natural killer T (NKT) cells. At the end of the article, we summarize the importance of CXCL16 in cancer therapy.

Long non‑coding RNA JPX promotes gastric cancer progression by regulating CXCR6 and autophagy via inhibiting miR‑197

Long non-coding RNAs (lncRNAs) serve a crucial role in gastric cancer (GC) progression. However, the molecular mechanism underlying lncRNA JPX transcript, XIST activator (JPX) in the tumorigenesis of GC is not completely understood. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were performed to detect gene expression. A luciferase reporter gene assay was conducted to determine the relationship between microRNA (miR)-197 and JPX or C-X-C motif chemokine receptor 6 (CXCR6). Cell viability, migration and invasion were determined by performing MTT, wound healing and Transwell assays, respectively. The Cancer Genome Atlas database and the RT-qPCR results indicated that JPX expression was upregulated and miR-197 expression was downregulated in patients with GC and in GC cells. Moreover, high JPX expression and low miR-197 expression in patients with GC indicated poor prognosis. miR-197 expression was directly inhibited by JPX. Compared with the short hairpin RNA (sh) negative control (NC) group, NCI-N87 and MKN-45 cells in the shJPX group displayed decreased cell viability and invasion, as well as a wider scratch width. NCI-N87 and MKN-45 cells in the shJPX + miR-197 inhibitor group had increased viability and invasion, but a narrower scratch width compared with the shJPX group. It was also identified that miR-197 directly inhibited CXCR6 expression. miR-197 inhibited Beclin1 protein expression and promoted p62 protein expression. Compared with the NC group, NCI-N87 and MKN-45 cells in the miR-197 mimic group had decreased cell viability and invasion, and a wider scratch width. Enhanced cell viability and invasion, and a narrower scratch width was also observed in the miR-197 mimic + CXCR6 and miR-197 mimic + Beclin1 groups, compared with the miR-197 mimic group. Collectively, the results indicated that lncRNA JPX promoted GC progression by regulating CXCR6 and autophagy via inhibiting miR-197. Furthermore, JPX knockdown regulated GC cell phenotype by promoting miR-197.

miR‑378 in combination with ultrasonic irradiation and SonoVue microbubbles transfection inhibits hepatoma cell growth

Ultrasonic microbubbles in combination with microRNA (miRNAs/miRs) exhibited promising effects on cancer treatments. The aim was to investigate the role of miR-378 in hepatoma cells and the efficiency of it in combination with ultrasonic irradiation and SonoVue^® microbubbles method for cell transfection. HuH-7, Hep3B and SK-Hep1 cells were transfected with an miR-378 mimic using only Lipofectamine^® 3000 or combined with SonoVue microbubbles and ultrasonic irradiation at 0.5 W/cm² for 30 sec. mRNAs and protein levels of Cyclin D1, Bcl-2, Bax, Akt, p53 and Survivin were detected by reverse transcription-quantitative PCR and western blotting, respectively. Cell survival rate, proliferation, cell cycle and apoptosis were determined by Cell Counting Kit-8, cell double cytochemical staining and flow cytometry, respectively. It was found that using a combination of ultrasonic irradiation and the SonoVue microbubbles method increased the effectiveness of miR-378 transfection into hepatocellular carcinoma (HCC) cells, and increased the inhibition of cell survival and proliferation. Moreover, miR-378 increased the rate of apoptosis and upregulated the expression of Bax and p53, and suppressed the cell cycle and downregulated the expression of Cyclin D1, Bcl-2, Akt, β-catenin and Survivin much more effectively in the HCC cell line by applying the combined method. Thus, miR-378 was shown to be a suppressive factor to reduce proliferation and increase apoptosis in HCC cells. Additionally, the combination of ultrasonic irradiation and SonoVue microbubbles method was more efficient in the transfection of miRNA.

Mesenchymal stem cell-derived CXCL16 promotes progression of gastric cancer cells by STAT3-mediated expression of Ror1

Bone marrow‐derived mesenchymal stem or stromal cells (MSC) have been shown to be recruited to various types of tumor tissues, where they interact with tumor cells to promote their proliferation, survival, invasion and metastasis, depending on the type of the tumor. We have previously shown that Ror2 receptor tyrosine kinase and its ligand, Wnt5a, are expressed in MSC, and Wnt5a‐Ror2 signaling in MSC induces expression of CXCL16, which, in turn, promotes proliferation of co–cultured MKN45 gastric cancer cells via the CXCL16‐CXCR6 axis. However, it remains unclear how CXCL16 regulates proliferation of MKN45 cells. Here, we show that knockdown of CXCL16 in MSC by siRNA suppresses not only proliferation but also migration of co–cultured MKN45 cells. We also show that MSC‐derived CXCL16 or recombinant CXCL16 upregulates expression of Ror1 through activation of STAT3 in MKN45 cells, leading to promotion of proliferation and migration of MKN45 cells in vitro. Furthermore, co–injection of MSC with MKN45 cells in nude mice promoted tumor formation in a manner dependent on expression of Ror1 in MKN45 cells, and anti–CXCL16 neutralizing antibody suppressed tumor formation of MKN45 cells co–injected with MSC. These results suggest that CXCL16 produced through Ror2‐mediated signaling in MSC within the tumor microenvironment acts on MKN45 cells in a paracrine manner to activate the CXCR6‐STAT3 pathway, which, in turn, induces expression of Ror1 in MKN45 cells, thereby promoting tumor progression.

Identification and validation of potential prognostic gene biomarkers for predicting survival in patients with acute myeloid leukemia

Background

Molecular analysis is a promising source of clinically useful prognostic biomarkers. The aim of this investigation was to identify prognostic biomarkers for patients with acute myeloid leukemia (AML) by using the gene expression profile dataset from public database.

Methods

The gene expression profile dataset and corresponding overall survival (OS) information of three cohorts of AML patients from GSE12417 and The Cancer Genome Atlas AML project (TCGA-LAML) were included in the present study. Prognostic gene screening was performed by using a survival package, whereas time-dependent receiver operating characteristic (ROC) curve analysis was performed using the survivalROC package.

Results

In the three cohorts, 11 genes were identified that were significantly associated with AML OS. A linear prognostic model of the 11 genes was constructed and weighted by regression coefficient (β) from the multivariate Cox regression analyses of GSE12417 HG-U133A cohort to divide patients into high- and low-risk groups. GSE12417 HG-U133 plus 2.0 and TCGA-LAML were validation cohorts. Patients assigned to the high-risk group exhibited poor OS compared to patients in the low-risk group. The 11-gene signature is a prognostic marker of AML and demonstrates good performance for predicting 1-, 3-, and 5-year OS as evaluated by survivalROC in the three cohorts.

Conclusion

Our study has identified an mRNA signature including 11 genes, which may serve as a potential prognostic marker of AML.

High expression of CXC chemokine receptor 6 associates with poor prognosis in patients with clear cell renal cell carcinoma

PURPOSE

Accumulating evidence indicates that CXC chemokine receptor 6 (CXCR6) has a crucial role in cancer development and progression, however, its role in clear cell renal cell carcinoma (ccRCC) remains obscure. The aim of this study is to investigate the prognostic value of CXCR6 expression in patients with ccRCC following surgery.

MATERIALS AND METHODS

This study retrospectively included 239 patients with ccRCC who underwent nephrectomy and had paraffin tissue available at a single center. CXCR6 expression in tumor tissue was evaluated by immunohistochemistry and its associations with overall survival (OS) and recurrence-free survival (RFS) were investigated.

RESULTS

A total of 47.3% tumors were considered as high expression of CXCR6, which was significantly associated with the male sex (P = 0.003) and high Fuhrman grade (P<0.001). A high expression of CXCR6 indicated a reduced OS (P<0.001) and RFS (P = 0.007). Multivariate analysis demonstrated that CXCR6 expression was an independent prognostic factor of OS (hazard ratio = 2.604; 95% CI: 1.338-5.068; P = 0.005) and RFS (hazard ratio = 1.957; 95% CI: 1.065-3.595; P = 0.031). Subgroup analysis found that CXCR6 expression could differentiate survival risks among patients with high-risk disease. Moreover, a nomogram integrating CXCR6 expression and traditional clinical and pathologic features was established and predicted postsurgical recurrence-risk well at 3- and 5-year.

CONCLUSIONS

The expression of CXCR6 in tumor tissue may serve as a potential prognostic biomarker to refine clinical prognosis prediction combined with traditional clinical and pathological analysis for patients with ccRCC after surgery.

Synergistic cytotoxic effects of arsenite and tetrandrine in human breast cancer cell line MCF-7

To provide novel insight into the development of new therapeutic strategies to combat breast cancer using trivalent arsenic (AsIII)-based combination therapy, the cytotoxicity of a combination of AsIII and tetrandrine (Tetra), a Chinese plant-derived alkaloid, was investigated in the human breast cancer cell line MCF-7. Cytotoxicity was evaluated using cell viability, colony formation, wound healing, lactate dehydrogenase leakage and cell cycle assay. Alterations of genes associated with cell proliferation and death were analyzed using real-time PCR and western blotting. Intracellular arsenic accumulation (As[i]) was also determined. Tetra significantly enhanced the cytotoxicity of AsIII in MCF-7 cells in a synergistic manner. The combined treatment upregulated the expression level of FOXO3a, and subsequently resulted in a concomitant increase in the expression levels of p21, p27, and decrease of cycline D1, which occurred in parallel with G0/G1 phase arrest. Autophagy induction was also observed in the combination treatment. Importantly, combining AsIII with Tetra exhibited a synergistic inhibitory effect on the expression level of survivin. Furthermore, enhanced As[i] along with synergistic cytotoxicity was observed in MCF-7 cells treated with AsIII combined with Tetra or Ko134, an inhibitor of breast cancer resistance protein (BCRP), suggesting that Tetra or the BCRP inhibitor probably intervened in the occurrence of resistance to arsenic therapy by enhancing the As[i] via modulation of multidrug efflux transporters. These results may provide a rational molecular basis for the combination regimen of AsIII plus Tetra, facilitating the development of AsIII-based anticancer strategies and combination therapies for patients with solid tumors, especially breast cancer.

CXCR6 predicts poor prognosis in gastric cancer and promotes tumor metastasis through epithelial-mesenchymal transition

Chemokines and their receptors have been confirmed to be involved in several types of cancer. However, little is known concerning the role of CXCL16 and its receptor CXCR6 in gastric cancer (GC) progression and metastasis. In the present study, expression of CXCL16 and CXCR6 in GC tumor and peritumoral tissues was detected by immunohistochemistry (IHC) in a cohort of 352 GC patients who underwent gastrectomy, and the correlation between CXCL16/CXCR6 expression and clinicopathological characteristics was further analyzed. To evaluate the function of CXCR6, we overexpressed and knocked down CXCR6 in GC cell lines. Results showed that expression of CXCR6, but not CXCL16, was significantly upregulated in GC tumor tissues, and was significantly correlated with lymph node and distant metastases, and advanced clinical stage in the GC patients. Survival analysis showed that large tumor size (>5 cm), elevated preoperative serum carcinoembryonic antigen (CEA) level, advanced TNM stage and high CXCR6 expression indicated worse overall survival (OS) and disease-free survival (DFS) in GC, and CXCR6 was an independent predictor for both OS and DFS in GC. In vitro experiments showed that CXCR6 overexpression induced cell migration and invasion ability, and promoted epithelial-mesenchymal transition of GC cells by upregulation of mesenchymal markers and inhibition of epithelial markers. In contrast, knockdown of CXCR6 in GC cells resulted in inhibition of cell proliferation, migration and invasion ability, and reversal of epithelial-mesenchymal transition (EMT) phenomenon. Our results demonstrated that CXCR6 is an independent prognostic factor for poor survival in GC patients, and may promote GC metastasis through EMT.

Lentivirus-mediated PLCγ1 gene short-hairpin RNA suppresses tumor growth and metastasis of human gastric adenocarcinoma

Targeted molecular therapy has gradually been a potential solution in cancer therapy. Other authors' and our previous studies have demonstrated that phosphoinositide-specific phospholipase γ (PLCγ) is involved in regulating tumor growth and metastasis. However, the molecular mechanism underlying PLCγ-dependent tumor growth and metastasis of gastric adenocarcinoma and whether PLCγ may be a potential target for tumor therapy in human gastric adenocarcinoma are not yet well determined. Here, we investigated the role of PLCγ inhibition in tumor growth and metastasis of human gastric adenocarcinoma using BGC-823 cell line and a nude mouse tumor xenograft model. The results manifested that the depletion of PLCγ1 by the transduction with lentivirus-mediated PLCγ1 gene short-hairpin RNA (shRNA) vector led to the decrease of tumor growth and metastasis of human gastric adenocarcinoma in vitro and in vivo. Furthermore, the Akt/Bad, Akt/S6, and ERK/Bad signal axes were involved in PLCγ1-mediated tumor growth and metastasis of human gastric adenocarcinoma. Therefore, the abrogation of PLCγ1 signaling by shRNA could efficaciously suppress human gastric adenocarcinoma tumor growth and metastasis, with important implication for validating PLCγ1 as a potential target for human gastric adenocarcinoma.

CXCR6 promotes tumor cell proliferation and metastasis in osteosarcoma through the Akt pathway

Chemokine (C-X-C motif) receptor 6 (CXCR6) is up-regulated in many malignancies, indicating that CXCR6 plays an important role in tumor progression. However, the expression and function of CXCR6 in osteosarcoma (OS) remains unclear. This study aimed to explore the expression levels and function of CXCR6 in OS tissues and osteosarcoma cell lines MG-63, HOS and U2OS. The protein expression levels of CXCR6 in OS patient tissues and three osteosarcoma cell lines MG-63, HOS and U2OS were assessed. CXCR6-overexpression MG-63 cell lines were established and then the proliferation, invasion and the epithelial-mesenchymal transition (EMT) in those cells were assessed. CXCR6 mRNA levels in OS tissues were significantly higher than those in normal bone tissues. Consistently, both of the mRNA and protein levels of CXCR6 in OS cell lines MG-63, HOS and U2OS were higher than those in normal bone cells hFOB1.19. CXCR6 overexpression not only promoted cell proliferation, invasion and EMT, but also enhanced the phosphorylation of Akt in MG-63 cells. After inhibition of Akt-phosphorylation by Akt inhibitor, LY2940023, CXCR6-induced cell proliferation and invasion were dramatically attenuated. In conclusion, the present study demonstrated that CXCR6 enhances OS cell proliferation and invasion through the Akt pathway.

A three-gene expression-based risk score can refine the European LeukemiaNet AML classification

Background

Risk stratification based on cytogenetics of acute myeloid leukemia (AML) remains imprecise. The introduction of novel genetic and epigenetic markers has helped to close this gap and increased the specificity of risk stratification, although most studies have been conducted in specific AML subpopulations. In order to overcome this limitation, we used a genome-wide approach in multiple AML populations to develop a robust prediction model for AML survival.

Methods

We conducted a genome-wide expression analysis of two data sets from AML patients enrolled into the AMLCG-1999 trial and from the Tumor Cancer Genome Atlas (TCGA) to develop a prognostic score to refine current risk classification and performed a validation on two data sets of the National Taiwan University Hospital (NTUH) and an independent AMLCG cohort.

Results

In our training set, using a stringent multi-step approach, we identified a small three-gene prognostic scoring system, named Tri-AML score (TriAS) which highly correlated with overall survival (OS). Multivariate analysis revealed TriAS to be an independent prognostic factor in all tested training and additional validation sets, even including age, current cytogenetic-based risk stratification, and three other recently developed expression-based scoring models for AML.

Conclusions

The Tri-AML score allows robust and clinically practical risk stratification for the outcome of AML patients. TriAS substantially refined current ELN risk stratification assigning 44.5 % of the patients into a different risk category.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0308-8) contains supplementary material, which is available to authorized users.

Flavones inhibit breast cancer proliferation through the Akt/FOXO3a signaling pathway

BACKGROUND

Flavones found in plants display various biological activities, including anti-allergic, anti-viral, anti-inflammatory, anti-oxidation, and anti-tumor effects. In this study, we investigated the anti-tumor effects of flavone, apigenin and luteolin on human breast cancer cells.

METHODS

The anti-cancer activity of flavone, apigenin and luteolin was investigated using the MTS assay. Apoptosis was analyzed by Hoechst 33342 staining, flow cytometry and western blot. Cell migration was determined using the culture inserts and xCELLigence real-time cell analyzer instrument equipped with a CIM-plate 16. Real-time quantitative PCR and western blot were used to determine the signaling pathway elicited by flavone, apigenin and luteolin.

RESULTS

Flavone, apigenin and luteolin showed potent inhibitory effects on the proliferation of Hs578T, MDA-MB-231 and MCF-7 breast cancer cells in a concentration and time-dependent manner. The ability of flavone, apigenin and luteolin to inhibit the growth of breast cancer cells through apoptosis was confirmed by Hoechst33342 staining and the induction of sub-G1 phase of the cell cycle. Flavone, apigenin and luteolin induced forkhead box O3 (FOXO3a) expression by inhibiting Phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB)/Akt. This subsequently elevated the expression of FOXO3a target genes, including the Cyclin-dependent kinase inhibitors p21Cip1 (p21) and p27kip1 (p27), which increased the levels of activated poly(ADP) polymerase (PARP) and cytochrome c.

CONCLUSION

Taken together, these data demonstrated that flavone, apigenin and luteolin induced cell cycle arrest and apoptosis in breast cancer cells through inhibiting PI3K/Akt activation and increasing FOXO3a activation, which suggest that flavone, apigenin and luteolin will be the potential leads for the preventing and treating of breast cancer.