Resistin stimulates PC-3 prostate cancer cell growth through stimulation of SOCS3 and SOCS5 genes.

Resistin and suppressors of cytokine signaling (SOCSs) have been reported to regulate prostate cancer (PCa) cell proliferation and survival, respectively. Whether any of the SOCS molecules mediate the mitogenic effect of resistin on PCa cells is unknown. Using PC-3 human PCa cells, we found that resistin upregulates the expression of SOCS3 and SOCS5 mRNA, but not SOCS7 mRNA, in a dose- and time-dependent manner. The resistin-induced increases in SOCS3 and SOCS5 expression and cell proliferation were prevented by pretreatment with specific inhibitors of the TLR4, ERK, p38 MAPK, JNK, PI3K, and JAK2 proteins. However, pretreatment with a TLR2 inhibitor had no effect on resistin-mediated SOCS3 and SOCS5 expression. In addition, the effects of resistin on SOCS3, SOCS5, and SOCS7 mRNA levels were cell type-specific. Overexpression of either SOCS3 or SOCS5 enhanced further resistin-stimulated growth of PC-3 cells, whereas silencing SOCS3 or SOCS5 antagonized resistin-increased cell growth. Further PCa tissue analysis demonstrated higher levels of RETN, TLR4, SOCS3, and SOCS5 mRNAs in cancer tissues than benign prostate hyperplasia and indicated positive correlations among RETN, TLR4, and SOCS5. These data suggest that SOCS5, TLR4, and, to a lesser extent, SOCS3 can mediate the mitogenic effect of resistin on PC-3 PCa cells.

Pancreatic cancer-derived small extracellular vesical ezrin activates fibroblasts to exacerbate cancer metastasis through STAT3 and YAP-1 signaling pathways.

Cancer-associated fibroblasts (CAFs), a major component of the tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC), play an important role in tumorigenesis, metastasis, and chemoresistance. Tumor-derived small extracellular vesicles (sEVs), which mediate cell-to-cell communication between cancer cells and fibroblasts, are also critical for cancer progression and metastasis. However, it remains unclear how PDAC cell-derived sEVs activate fibroblasts, which contributes to tumor progression. Here, we report that ezrin (EZR) expression in PDAC cell-derived sEVs (sEV-EZR) can activate fibroblasts, resulting in increased migration ability and high expression of α-SMA, PDGFRB, and high production of extracellular matrix in fibroblasts. Reciprocally, sEV-EZR-activated fibroblasts enhanced PDAC cell proliferation, invasion, and metastasis to the liver in animal models. Conversely, fibroblasts treated with PDAC cell-derived sEVs with EZR knockdown resulted in the reduced metastatic ability of PDAC. Mechanistically, we demonstrated that PDAC cell-derived sEV-EZR increases the STAT3 and YAP-1 signaling pathways to induce fibroblast activation, and the activated fibroblasts promote PDAC cell proliferation, invasion, and liver metastasis. Inhibition of the STAT3 and YAP-1 signaling pathways by gene knockdown can abrogate sEV-EZR-induced effects. These findings suggest that targeting the interaction between PDAC cell-derived sEV-EZR and fibroblasts is a potential therapeutic strategy for PDAC.

MiR-944/CISH mediated inflammation via STAT3 is involved in oral cancer malignance by cigarette smoking.

The cytokine-inducible Src homology 2-containing protein (CISH) is an endogenous suppressors of signal transduction and activator of transcription (STAT) and acts as a key negative regulator of inflammatory cytokine responses. Downregulation of CISH has been reported to associate with increased activation of STAT and enhanced inflammatory pathways. However, whether microRNAs (miRNAs) play a crucial role in CISH/STAT regulation in oral squamous cell carcinoma (OSCC) remains unknown. The expression of CISH on OSCC patients was determine by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. Specific targeting by miRNAs was determined by software prediction, luciferase reporter assay, and correlation with target protein expression. The functions of miR-944 and CISH were accessed by transwell migration and invasion analyses using gain- and loss-of-function approaches. Enzyme-linked immunosorbent assay (ELISA) and qRT-PCR were used to evaluate the pro-inflammation cytokines expression under the miR-944, CISH, NNK or combinations treatment. We found that the CISH protein, which modulates STAT3 activity, as a direct target of miR-944. CISH protein was significantly down-regulated in OSCC patients and cell lines and its level was inversely correlated with miR-944 expression. The miR-944-induced STAT3 phosphorylation, pro-inflammation cytokines secretion, migration and invasion were abolished by CISH restoration, suggesting that the oncogenic activity of miR-944 is CISH dependent. Furthermore, tobacco extract (NNK) may contribute to miR-944 induction and STAT3 activation. Antagomir-mediated inactivation of miR-944 prevented the NNK-induced STAT3 phosphorylation and pro-inflammation cytokines secretion. Altogether, these data demonstrate that NNK-induced miR944 expression plays an important role in CISH/STAT3-mediated inflammatory response and activation of tumor malignancy.

MiR-30a and miR-379 modulate retinoic acid pathway by targeting DNA methyltransferase 3B in oral cancer.

BACKGROUND: Epigenetic silencing of retinoic acid (RA) signaling-related genes have been linked with the pathogenesis and clinical outcome in oral squamous cell carcinoma (OSCC) carcinogenesis. However, the precise mechanisms underlying the abnormal silencing of RA signaling-related genes in OSCC have not been well investigated. METHODS: Using combined analysis of genome-wide gene expression and methylation profile from 40 matched normal-tumor pairs of OSCC specimens, we found a set of retinoid signaling related genes are frequently hypermethylated and downregulated in OSCC patient samples, including alcohol dehydrogenase, iron containing 1 (ADHFE1) and aldehyde dehydrogenase 1 family, member A2 (ALDH1A2), which are the important rate-limiting enzymes in synthesis of RA. The expression of ADHFE1 and ALDH1A2 in OSCC patients was determine by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. The binding sites of miR-30a and miR-379 with DNA methyltransferase 3B (DNMT3B) were predicted using a series of bioinformatic tools, and validated using dual luciferase assay and Western blot analyses. The functions of miR-30a, miR-379, and DNMT3B were accessed by growth and colony formation analyses using gain- and loss-of-function approaches. Chromatin immunoprecipitation (ChIP) was performed to explore the molecular mechanisms by arecoline and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) treatment. RESULTS: We demonstrated that deregulated miR-30a and miR-379 could represent a mechanism for the silencing of ADHFE1 and ALDH1A2 in OSCC through targeting DNMT3B. Ectopic expression of miR-30a and miR-379 could induce re-expression of methylation-silenced ADHFE1 and ALDH1A2, and lead to growth inhibition in oral cancer cells. Furthermore, the dysregulation of the miRNAs and DNMT-3B may result from exposure to tobacco smoking and betel quid chewing. CONCLUSIONS: Our results demonstrate that tobacco smoking and betel quid chewing could repress miR-30a and miR-379, which upregulate the DNMT3B expression, in turn, lead to the hypermethylation of ADHFE1 and ALDH1A genes, consequently, promote the oncogenic activity. These findings highlight the potential use of retinoids in combination with epigenetic modifiers for the prevention or treatment of oral cancer.

Pancreatic cancer-derived small extracellular vesical Ezrin regulates macrophage polarization and promotes metastasis.

Small extracellular vesicles (sEVs) mediate the interaction between tumor and tumor-associated macrophages (TAMs). This study aims to demonstrate that the pancreatic ductal adenocarcinoma (PDAC)-derived sEV Ezrin (sEV-EZR) could modulate macrophage polarization and promote PDAC metastasis. We isolated PDAC-derived sEVs and plasma sEVs from PDAC patients. Human blood mononuclear cell (PBMC)-derived macrophages were treated with PDAC-derived sEVs or the counterpart depleted Ezrin (EZR) with shRNA-mediated knockdown. We used enzyme-linked immunosorbent assays and flow cytometry to monitor macrophages polarization. NOD/SCID/IL2Rγnull mice were treated with sEVs to study PDAC liver metastasis. The plasma sEV-EZR levels of 165 PDAC patients and 151 high-risk controls were analyzed. The EZR levels are higher in sEVs derived from PDAC cells and PDAC-patient plasma than that of the normal controls. PDAC-derived sEVs modulate the polarization of macrophages to M2 phenotype, while PDAC-shEZR-derived sEVs polarize macrophages into M1 phenotype. We found an increase in M1 TAMs and a decrease in M2 TAMs in orthotropic tumors treated with PDAC-shEZR-derived sEVs. The amount of liver metastasis in PDAC-shEZR-derived sEVs-treated mice was observed to be smaller than that of controls. The mean plasma sEV-EZR levels from PDAC patients were significantly higher than those from the controls (32.43±20.78 vs. 21.88±11.43 pg/ml; P<0.0001). The overall survival in the high-plasma sEV-EZR patients was significantly shorter than that in the low-EZR group (6.94±15.25 vs. 9.63±15.11 months; P=0.0418). sEV-EZR could modulate macrophage polarization and promote metastasis in PDAC. Targeting sEV-EZR can be considered a promising therapeutic strategy to inhibit PDAC metastasis.

MicroRNA-486-3p functions as a tumor suppressor in oral cancer by targeting DDR1.

BACKGROUND: Discoidin domain receptor-1 (DDR1) tyrosine kinase is highly expressed in a variety of human cancers and involved in various steps of tumorigenesis. However, the precise mechanisms underlying the abnormal expression of DDR1 in oral squamous cell carcinoma (OSCC) has not been well investigated. METHODS: The expression of DDR1 on OSCC patients was determine by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. Specific targeting by miRNAs was determined by software prediction, luciferase reporter assay, and correlation with target protein expression. The functions of miR-486-3p and DDR1 were accessed by MTT and Annexin V analyses using gain- and loss-of-function approaches. Chromatin immunoprecipitation (ChIP) and methylation specific PCR (MSP) were performed to explore the molecular mechanisms by arecoline treatment. RESULTS: Here, we reported that DDR1 was significantly upregulated in OSCC tissues and its levels were inversely correlated with miR-486-3p expression. The experimental results in vitro confirmed that miR-486-3p decreased DDR1 expression by targeting the 3'-UTR of DDR1 mRNA. Overexpression of miR-486-3p led to growth inhibition and apoptosis induction with a similar function by knockdown of DDR1. Aberrant methylation of ANK1 promoter was a highly prevalent in OSCC and contributes to oral carcinogenesis by epigenetic silencing of ANK1 and miR-486-3p. We found that miR-486-3p can be transcriptionally co-regulated with its host gene ANK1 through epigenetic repression. DNA methylation inhibitor treatment re-expressed ANK1 and miR-486-3p. Importantly, arecoline, a major betel nut alkaloid, recruited DNMT3B binding to ANK1 promoter for DNA methylation and then attenuated the expression of miR-486-3p in OSCC. CONCLUSION: This study was the first to demonstrate that betel nut alkaloid may recruit DNMT3B to regulate miR-486-3p/DDR1 axis in oral cancer andmiR-486-3p and DDR1 may serve as potential therapeutic targets of oral cancer.

TNF-α-induced miR-450a mediates TMEM182 expression to promote oral squamous cell carcinoma motility.

Distant metastasis leads oral cancer patients into a poor survival rate and a high recurrence stage. During tumor progression, dysregulated microRNAs (miRNAs) have been reported to involve tumor initiation and modulate oral cancer malignancy. MiR-450a was significantly upregulated in oral squamous cell carcinoma (OSCC) patients without functional reports. This study was attempted to uncover the molecular mechanism of novel miR-450a in OSCC. Mir-450a expression was examined by quantitative RT-PCR, both in OSCC cell lines and patients. Specific target of miR-450a was determined by software prediction, luciferase reporter assay, and correlation with target protein expression. The functions of miR-450a and TMEM182 were accessed by adhesion and transwell invasion analyses. Determination of the expression and cellular localization of TMEM182 was examined by RT-PCR and by immunofluorescence staining. The signaling pathways involved in regulation of miR-450a were investigated using the kinase inhibitors. Overexpression of miR-450a in OSCC cells impaired cell adhesion ability and induced invasiveness, which demonstrated the functional role of miR-450a as an onco-miRNA. Interestingly, tumor necrosis factor alpha (TNF-α)-mediated expression of TMEM182 was regulated by miR-450a induction. MiR-450a-reduced cellular adhesion was abolished by TMEM182 restoration. Furthermore, the oncogenic activity of TNF-α/miR-450a/TMEM182 axis was primarily through activating extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. ERK1/2 inhibitor prevented the TNF-α-induced miR-450a expression and enhanced adhesion ability. Our data suggested that TNF-α-induced ERK1/2-dependent miR-450a against TMEM182 expression exerted a great influence on increasing OSCC motility. Overall, our results provide novel molecular insights into how TNF-α contributes to oral carcinogenesis through miR-450a that targets TMEM182.

Thrombospondin-2 is a Highly Specific Diagnostic Marker and is Associated with Prognosis in Pancreatic Cancer.

BACKGROUND: Thrombospondin-2 (TSP-2) has been reported as an early diagnostic marker for pancreatic ductal adenocarcinoma (PDAC) in Caucasian populations. This study was designed to validateTSP-2 as a diagnostic marker in a large Taiwan cohort and to investigate the association of TSP-2 with the clinical outcomes of PDAC patients. METHODS: The serum TSP-2 levels in 263 PDAC patients and 230 high-risk individuals (HRIs) were measured via an enzyme-linked immunosorbent assay. The sensitivity, specificity, and accuracy of TSP-2 as a diagnostic marker to discriminating PDAC patients from HRIs and correlations between TSP-2 levels and prognosis of PDAC patients were analyzed. RESULTS: Serum TSP-2 levels were significantly higher in patients with PDAC (44.90 ± 40.70 ng/ml) than in the HRIs (17.52 ± 6.23 ng/ml). At a level of ≥ 29.8 ng/ml, TSP-2 exhibited 100% specificity, 55.9% sensitivity, 100% positive predictive value (PPV), and 66.5% negative predictive value (NPV) for discriminating PDAC patients from HRIs. The Cox regression analysis showed that higher serum TSP-2 levels were significantly associated with poor outcomes in PDAC patients (hazard ratio = 1.54, 95% confidence interval = 1.143-2.086, P = 0.005). Combining the carbohydrate antigen 19-9 (CA19-9) (cutoff value of 62.0 U/ml) and TSP-2 (cutoff value of 29.8 ng/ml) levels yielded 98.7% specificity, 90.5% sensitivity, 98.8% PPV, and 90.1% NPV for discriminating patients with PDAC from HRIs. CONCLUSIONS: TSP-2 is a highly specific diagnostic marker and an independent prognostic marker in patients with PDAC. A combined biomarker panel, including TSP-2 and CA19-9, may facilitate future PDAC screening.

Parathyroid Hormone-Like Hormone is a Poor Prognosis Marker of Head and Neck Cancer and Promotes Cell Growth via RUNX2 Regulation.

Parathyroid Hormone-Like Hormone (PTHLH) is an autocrine/paracrine ligand that is up-regulated in head and neck squamous cell carcinoma (HNSCC). However, the cellular function and regulatory mechanism in HNSCC remains obscure. We investigated the clinical significance of PTHLH in HNSCC patients, and verified the role of RUNX2/PTHLH axis, which is stimulated HNSCC cell growth. In patients, PTHLH is a poor prognosis marker. PTHLH expression lead to increasing the cell proliferation potential through an autocrine/paracrine role and elevating blood calcium level in Nod-SCID mice. In public HNSCC microarray cohorts, PTHLH is found to be co-expressed with RUNX2. Physiologically, PTHLH is regulated by RUNX2 and also acting as key calcium regulator. However, elevations of calcium concentration also increased the RUNX2 expression. PTHLH, calcium, and RUNX2 form a positive feedback loop in HNSCC. Furthermore, ectopic RUNX2 expression also increased PTHLH expression and promoted proliferation potential through PTHLH expression. Using cDNA microarray analysis, we found PTHLH also stimulated expression of cell cycle regulators, namely CCNA2, CCNE2, and CDC25A in HNSCC cells, and these genes are also up-regulated in HNSCC patients. In summary, our results reveal that PTHLH expression is a poor prognosis marker in HNSCC patients, and RUNX2-PTHLH axis contributes to HNSCC tumor growth.

Dysregulation of RUNX2/Activin-A Axis upon miR-376c Downregulation Promotes Lymph Node Metastasis in Head and Neck Squamous Cell Carcinoma.

Epigenetic correlates of the head and neck cancer may illuminate its pathogenic roots. Through a gene set enrichment analysis, we found that the oncogenic transcription factor RUNX2 is widely upregulated in the head and neck squamous cell carcinoma (HNSCC) with lymph node metastasis, where it also predicts poor prognosis in patients with HNSCC. Enforced expression of ectopic RUNX2 promoted the metastatic capabilities of HNSCC, whereas RUNX2 silencing inhibited these features. Mechanistic investigations showed that manipulating levels of activin A (INHBA) could rescue or compromise the RUNX2-mediated metastatic capabilities of HNSCC cells. Furthermore, we found that miR-376c-3p encoded within the 3'-untranslated region of RUNX2 played a pivotal role in regulating RUNX2 expression in highly metastatic HNSCC cells, where it was downregulated commonly. Restoring miR-376c expression in this setting suppressed expression of RUNX2/INHBA axis along with metastatic capability. Clinically, we observed an inverse relationship between miR-376c-3p expression and the RUNX2/INHBA axis in HNSCC specimens. In summary, our results defined a novel pathway in which dysregulation of the RUNX2/INHBA axis due to miR-376c downregulation fosters lymph node metastasis in HNSCC. Cancer Res; 76(24); 7140-50. ©2016 AACR.

MPT0B098, a Microtubule Inhibitor, Suppresses JAK2/STAT3 Signaling Pathway through Modulation of SOCS3 Stability in Oral Squamous Cell Carcinoma.

Microtubule inhibitors have been shown to inhibit Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signal transduction pathway in various cancer cells. However, little is known of the mechanism by which the microtubule inhibitors inhibit STAT3 activity. In the present study, we examined the effect of a novel small-molecule microtubule inhibitor, MPT0B098, on STAT3 signaling in oral squamous cell carcinoma (OSCC). Treatment of various OSCC cells with MPT0B098 induced growth inhibition, cell cycle arrest and apoptosis, as well as increased the protein level of SOCS3. The accumulation of SOCS3 protein enhanced its binding to JAK2 and TYK2 which facilitated the ubiquitination and degradation of JAK2 and TYK2, resulting in a loss of STAT3 activity. The inhibition of STAT3 activity led to sensitization of OSCC cells to MPT0B098 cytotoxicity, indicating that STAT3 is a key mediator of drug resistance in oral carcinogenesis. Moreover, the combination of MPT0B098 with the clinical drug cisplatin or 5-FU significantly augmented growth inhibition and apoptosis in OSCC cells. Taken together, our results provide a novel mechanism for the action of MPT0B098 in which the JAK2/STAT3 signaling pathway is suppressed through the modulation of SOCS3 protein level. The findings also provide a promising combinational therapy of MPT0B098 for OSCC.

IL-8 induces miR-424-5p expression and modulates SOCS2/STAT5 signaling pathway in oral squamous cell carcinoma.

Suppressor of cytokine signaling (SOCS) proteins are negative feedback regulators of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Dysregulation of SOCS protein expression in cancers can be one of the mechanisms that maintain STAT activation, but this mechanism is still poorly understood in oral squamous cell carcinoma (OSCC). Here, we report that SOCS2 protein is significantly downregulated in OSCC patients and its levels are inversely correlated with miR-424-5p expression. We identified the SOCS2 protein, which modulates STAT5 activity, as a direct target of miR-424-5p. The miR-424-5p-induced STAT5 phosphorylation, matrix metalloproteinases (MMPs) expression, and cell migration and invasion were blocked by SOCS2 restoration, suggesting that miR-424-5p exhibits its oncogenic activity through negatively regulating SOCS2 levels. Furthermore, miR-424-5p expression could be induced by the cytokine IL-8 primarily through enhancing STAT5 transcriptional activity rather than NF-κB signaling. Antagomir-mediated inactivation of miR-424-5p prevented the IL-8-induced cell migration and invasion, indicating that miR-424-5p is required for IL-8-induced cellular invasiveness. Taken together, these data indicate that STAT5-dependent expression of miR-424-5p plays an important role in mediating IL-8/STAT5/SOCS2 feedback loop, and scavenging miR-424-5p function using antagomir may have therapeutic potential for the treatment of OSCC.

RAD001-mediated STAT3 upregulation and megakaryocytic differentiation.

RAD001 is currently used as an immunosuppressant and anticancer drug. Megakaryocyte (MK) differentiation includes development from pluripotent stem cells to proliferation and differentiation toward MK formation and platelet maturation. Our preliminary assay showed that RAD001 might stimulate MK differentiation; however, the exact regulatory mechanisms needed to be elucidated. By the ex vivo assay, RAD001 induced MK differentiation in human haematopoietic stem cells, with both the stimulation of CFU-GM colony formation and CD61 surface marker expression. Then, BALB/c mice were orally administrated with or without agrylin and/or RAD001 for 15 days. The platelet count and bone marrow CFU-MK colony formation were eliminated by agrylin, but unchanged in RAD001 and RAD001 plus agrylin mice. An ex vivo assay of bone marrow-derived stem cells demonstrated that RAD001 increased the number of CFU-MK colonies. The MK count in bone section indicated the decreased effect by agrylin and then recovered by RAD001. The level of plasma thrombopoietin was also enhanced in RAD001-treated mice. The effect of RAD001 on human leukaemic K562 and HEL cells showed the growth inhibition and MK differentiation activities; including morphological observation, CD41 and CD61 expression, and platelet factor 4 secretion. In RAD001-treated HEL cells, p-STAT3 expression, STAT3 translocation, and STAT3-DNA binding activity were up-regulated. Furthermore, STAT3 siRNA decreased the p-STAT3 and CD61 expression, as well as the CD61 fluorescence intensity, indicating that STAT3 may be critical in RAD001-mediated MK differentiation. Conclusion, the present study demonstrated that RAD001 might have the capacity to induce MK differentiation through the up-regulation of STAT3 signalling.

Staurosporine induces megakaryocytic differentiation through the upregulation of JAK/Stat3 signaling pathway.

The induction of megakaryocyte (MK) differentiation is a potent strategy for the clinical treatment of diseases related to blood platelet disorders. Staurosporine (STS) is an inhibitor of protein kinase C (PKC) with an inhibitory effect on cancer cells through apoptosis induction. However, the exact mechanism of STS on MK differentiation is still unclear. The present study assessed the regulatory effect of STS on MK differentiation in both human leukemia cells and mouse bone marrow-derived stem cells. STS not only inhibited the proliferation of both K562 and HEL cell lines, but also induced the cell differentiation into MK lineage, resulting in polyploidy formation, MK-specific markers CD41 and CD61 expression, and platelet factor 4 (PF4) secretions of cells. The induction effect of STS was upregulated through the expression of Stat3, but not PKC. The level of phosphorylated (p)-Stat3 showed an increased expression, translocated to the nucleus, and enhanced the DNA-binding activity in STS-treated cells. Blockage Stat3 and its upstream molecule JAK by Stat3 inhibitor VI and JAK inhibitor I, respectively, demonstrated that the cells obviously reduced the percentage of STS-mediated MK differentiation. Further investigation of the cells with Stat3 siRNA transfection showed that p-Stat3 and MK differentiation was markedly decreased, indicating that Stat3 is an important molecule in inducing MK differentiation. Additionally, the ex vivo assay also confirmed that STS effectively stimulated CFU-MK colony formation and CD61 expression in bone marrow cells. In conclusion, STS is a potent inducer for MK differentiation through the upregulation of JAK/Stat3 signaling pathway and p-Stat3 nuclear translocation.