Nuclear STAT3 Research Articles

Anticancer effect of SZC015 on pancreatic cancer via mitochondria-dependent apoptosis and the constitutive suppression of activated nuclear factor κB and STAT3 in vitro and in vivo.

Pancreatic cancer is the fourth leading cause of cancer-related death worldwide. Advances in therapeutic strategies such as chemotherapy have improved the clinical outcomes for pancreatic cancer patients. However, developing new therapeutic compounds against pancreatic cancer is still urgent due to the poor prognosis. Here, we show that SZC015, an oleanolic acid derivative, exhibits potent inhibitory effect on both pancreatic cancer cells in vitro and the corresponding xenograft tumors in vivo. Mechanistically, the activation of intrinsic apoptosis and G1 phase arrest resulting from mitochondria damage caused by SZC015 contribute significantly to the anticancer effects of SZC015. SZC015 also has remarkably inhibitory effects on the transcription factors that are extensively activated in pancreatic cancer tissues. As a constitutively activated transcription factor in pancreatic cancer, the nuclear factor κB is highly suppressed after SZC015 treatment in vitro or administration in vivo. Based on the bioinformatics analysis of microarray data, we validate that JAK2/STAT3 signaling is indeed activated in the human pancreatic cancer tissues and SZC015 also shows inhibitory effect on this signaling both in vitro and in vivo. These data suggest the potent effects of SZC015 on pancreatic cancer and also provided novel insights into the mechanisms of SZC015 as a new potent candidate for treating pancreatic cancer.

STAT6 expression in spindle cell lesions of the breast: An immunohistochemical study of 48 cases

The diagnosis of spindle cell lesions of the breast parenchyma is challenging. Some of these lesions share the expression of CD34, posing differential diagnostic problems, especially in core biopsies. Recently, antibodies against the STAT6 C-terminal, are being used in paraffin-embedded tissues as a surrogate for identifying the NAB2–STA6 fusion gene which is considered a specific molecular marker for solitary fibrous tumor. Accordingly, we investigated the expression of STAT6 in a large series of uncommon spindle cell tumor-like and tumor lesions occurring primarily in the breast parenchyma. We collected 10 classic-type myofibroblastomas, 9 desmoid-type fibromatosis, 6 spindle cell metaplastic carcinoma, 5 benign fibroblastic spindle cell tumors, 3 solitary fibrous tumors, 7 pseudoangiomatous stromal hyperplasias, 2 reactive spindle cell nodules, 1 leiomyoma, 1 spindle cell lipoma, 1 case of inflammatory pseudotumor, 1 nodular fasciitis, 1 myxoma and 1 dermatofibrosarcoma protuberans. A diffuse and strong nuclear STAT6 expression was restricted only to solitary fibrous tumors, while the other lesions were negative or showed only weak cytoplasmic expression. The present study confirms that the demonstration of a diffuse and strong STAT6 nuclear staining is very helpful in distinguishing solitary fibrous tumor from other spindle cell mimics arising in the breast.

Diets, functional foods, and nutraceuticals as alternative therapies for inflammatory bowel disease: Present status and future trends.

Inflammatory bowel disease (IBD) is a serious health concern among western societies. The disease is also on the rise in some East Asian countries and in Australia. Health professionals and dietitians around the world are facing an unprecedented challenge to prevent and control the increasing prevalence of IBD. The current therapeutic strategy that includes drugs and biological treatments is inefficient and are associated with adverse health consequences. In this context, the use of natural products is gaining worldwide attention. In vivo studies and clinical evidence suggest that well-planned dietary regimens with specific nutrients can alleviate gastrointestinal inflammation by modulating inflammatory cytokines, such as tumor necrosis factor α (TNF-α), interleukin 1 (IL-1), IL-6, IL-1β, and IL-10. Alternatively, the avoidance of high-fat and high-carbohydrate diets is regarded as an effective tool to eliminate the causes of IBD. Many functional foods and bioactive components have received attention for showing strong therapeutic effects against IBD. Both animal and human studies suggest that bioactive functional foods can ameliorate IBD by downregulating the pro-inflammatory signaling pathways, such as nuclear factor κB, STAT1, STAT6, and pro-inflammatory cytokines, including IL-1β, IL-4, IL-6, COX-2, TNF-α, and interferon γ. Therefore, functional foods and diets have the potential to alleviate IBD by modulating the underlying pathogenic mechanisms. Future comprehensive studies are needed to corroborate the potential roles of functional foods and diets in the prevention and control of IBD.

PO-507 Deregulated mechanisms downstream of PLCG1 promoting cutaneous T cell lymphomaprogression

IntroductionCutaneous T Cell Lymphoma (CTCL) is a heterogeneous group of non-Hodgkin lymphomas with unfavourable prognosis at advanced stages. The malignant network that control the development of CTCL is now starting to be characterised. NGS-derived studies have identified multiple molecular alterations in specific genes and signalling pathways including PLCG1 and JAK-STAT. It has been shown that up to 50% of CTCL cases develop deregulated PLCG1-downstream signalling as shown by activating PLCG1 mutations and PRKCQ amplifications. Also, frequent mutations in JAK1 and JAK3 and in members of the STAT family have been identified, thus revealing a potentially important role of these signalling pathways in CTCL. We aimed at exploring the interactions between deregulated PLCG1 and JAK-STAT activity in CTCL using pre-clinical models and in samples from CTCL patients at different stages of the disease.Material and methodsHEK-BlueTM IL-6 and CTCL cell lines were used to study PLCG1 downstream signalling towards NFAT and STAT3 activation. Immunohistochemistry (IHC) of NFAT, pSTAT1, pSTAT3, pSTAT5, p50, p52, p65 and RelB wasperformed in 71 patient samples. The status of PRKCQ was analysed in 45 samples by fluorescent in situhybridization (FISH).Results and discussionsDeregulated PLCG1 activity elicited NFAT and STAT3 activation ex vivo. Downstream of PLCG1, pharmacological and genetic inhibition of PRKCQ negatively affected NFAT and STAT3 activation whereas a constitutively active PRKCQ mutant (A148E) was sufficient to trigger their transcriptional activity. Our data shows that downstream of PLCG1, PRKCQ can activate transcription mediated by both NFAT and STAT proteins. We also analysed nuclear accumulation of NFAT, STAT and NF-κB family proteins by IHC in patient samples. Interestingly positive P-STAT3 staining correlated with advanced diseases. Moreover, most CTCL-tumour stage cases studied were positive for PRKCQ amplification and/or 10q23 polysomy.ConclusionOur results support PLCG1 playing a mayor role at controlling CTCL progression towards advanced stages. Downstream of PLCG1 or due to genetic amplification, PRKCQ can mediate the activation of NFAT and STAT3. Thus, mutations in PLCG1, PRKCQ amplifications and/or nuclear NFAT and STAT3 accumulation can serve as diagnostic markers for CTCL. Moreover, these can also provide rational to develop specific therapies targeting PRKCQ alone or in combination with calcineurin or JAK-STAT inhibitors.

Differentially localized survivin and STAT3 as markers of gastric cancer progression: Association with Helicobacter pylori.

Localization and differential expression of STAT3 and survivin in cancer cells are often related to distinct cellular functions. The involvement of survivin and STAT3 in gastric cancer has been reported in separate studies but without clear understanding of their kinetics in cancer progression. We examined intracellular distribution of STAT3 and survivin in gastric adenocarcinoma and compared it with normal and precancer tissues using immunoblotting and immunohistochemistry. Analysis of a total of 156 gastric samples comprising 61 histologically normal, 30 precancerous tissues (comprising intestinal metaplasia and dysplasia), and 65 adenocarcinomas, collected as endoscopic biopsies from treatment naïve study participants, revealed a significant (P<.001) increase in overall protein levels. Survivin expression was detectable in both cytoplasmic (90.8%) and nuclear (87.7%) compartments in gastric adenocarcinomas lesions. Precancerous dysplastic gastric lesions exhibited a moderate survivin expression (56.7%) localized in cytoplasmic compartment. Similarly, STAT3 and pSTAT3 expression was detected at high level in gastric cancer lesions. The levels of compartmentalized expression of survivin and STAT3/pSTAT3 correlated in precancerous and adenocarcinoma lesions. Although overexpression of these proteins was found associated with the tobacco use and alcohol consumption, their expression invariably and strongly correlated with concurrent Helicobacter pylori infection. Receiver operating characteristic analysis of nuclear survivin, STAT3, and pSTAT3 in different study groups showed acceptable positive and negative predictive values with area under the curve above 0.8 (P<.001). Overall, our results suggest that overall increase in survivin and STAT3 and their subcellular localization are key determinants of gastric cancer progression, which can be collectively used as potential disease biomarkers and therapeutic targets for gastric cancer.

Cardiotrophin-1 attenuates experimental colitis in mice.

Cardiotrophin-1 (CT-1) holds potent anti-inflammatory, cytoprotective, and anti-apoptotic effects in the liver, kidneys, and heart. In the present study, the role of endogenous CT-1 and the effect of exogenous CT-1 were evaluated in experimental ulcerative colitis. Colitis was induced in CT-1 knockout and wild-type (WT) mice by administration of dextran sulphate sodium (DSS) in the drinking water during 7 days. CT-1 knockout mice showed higher colon damage and disease severity than WT mice. In addition, CT-1 (200 µg/kg/day, iv) or vehicle (as control) was administered during 3 days to WT, colitic mice, starting on day 4 after initiation of DSS. Disease activity index (DAI), inflammatory markers (tumor necrosis factor α (TNF-α), INFγ, IL-17, IL-10, inducible nitric oxide synthase (iNOS)), colon damage, apoptosis (cleaved caspase 3), nuclear factor κB (NFκB) and STAT-3 activation, and bacterial translocation were measured. Compared with mice treated with DSS, mice also treated with exogenous CT-1 showed lower colon damage, DAI, plasma levels of TNFα, colon expression of TNF-α, INFγ, IL-17, iNOS and cleaved caspase 3, higher NFκB and signal transducer and activator of transcription 3 (STAT3) pathways activation, and absence of bacterial translocation. We conclude that endogenous CT-1 plays a role in the defense and repair response of the colon against ulcerative lesions through an anti-inflammatory and anti-apoptotic effect. Supplementation with exogenous CT-1 ameliorates disease symptoms, which opens a potentially new therapeutic strategy for ulcerative colitis.

TRIM59 Promotes Gliomagenesis by Inhibiting TC45 Dephosphorylation of STAT3.

Aberrant EGFR signaling is a common driver of glioblastoma (GBM) pathogenesis; however, the downstream effectors that sustain this oncogenic pathway remain unclarified. Here we demonstrate that tripartite motif-containing protein 59 (TRIM59) acts as a new downstream effector of EGFR signaling by regulating STAT3 activation in GBM. EGFR signaling led to TRIM59 upregulation through SOX9 and enhanced the interaction between TRIM59 and nuclear STAT3, which prevents STAT3 dephosphorylation by the nuclear form of T-cell protein tyrosine phosphatase (TC45), thereby maintaining transcriptional activation and promoting tumorigenesis. Silencing TRIM59 suppresses cell proliferation, migration, and orthotopic xenograft brain tumor formation of GBM cells and glioma stem cells. Evaluation of GBM patient samples revealed an association between EGFR activation, TRIM59 expression, STAT3 phosphorylation, and poor prognoses. Our study identifies TRIM59 as a new regulator of oncogenic EGFR/STAT3 signaling and as a potential therapeutic target for GBM patients with EGFR activation.Significance: These findings identify a novel component of the EGFR/STAT3 signaling axis in the regulation of glioma tumorigenesis. Cancer Res; 78(7); 1792-804. ©2018 AACR.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

STAT3 contributes to lysosomal-mediated cell death in a novel derivative of riccardin D-treated breast cancer cells in association with TFEB

RDD648, a novel derivative of a natural molecule riccardin D, exhibited potent anticancer activity by targeting lysosomes in vitro and in vivo. Mechanistic studies revealed that RDD648 facilitated STAT3 to translocate into the nucleus, and this activity was involved in lysosome-mediated cell death as evidenced by our finding that inhibition of STAT3 alleviated lysosomal membrane permeabilization. Further investigation indicated that nuclear STAT3 directly interacted with transcription factor TFEB, leading to the partial loss of function of TFEB, which is essential for lysosome turnover. The present study first uncovers that STAT3 contributes to lysosomal-mediated cell death in RDD648-treated breast cancer cells though interacting with TFEB, and the findings may be significant in the design of treatments for breast cancers where STAT3 is constitutively expressed.

STAT1 is a sex-specific tumor suppressor in colitis-associated colorectal cancer.

The interferon‐inducible transcription factor STAT1 is a tumor suppressor in various malignancies. We investigated sex‐specific STAT1 functions in colitis and colitis‐associated colorectal cancer (CRC) using mice with specific STAT1 deletion in intestinal epithelial cells (STAT1∆IEC). Male but not female STAT1∆IEC mice were more resistant to DSS‐induced colitis than sex‐matched STAT1flox/flox controls and displayed reduced intraepithelial infiltration of CD8+ TCRαβ+ granzyme B+ T cells. Moreover, DSS treatment failed to induce expression of T‐cell‐attracting chemokines in intestinal epithelial cells of male but not of female STAT1∆IEC mice. Application of the AOM‐DSS protocol for induction of colitis‐associated CRC resulted in increased intestinal tumor load in male but not in female STAT1∆IEC mice. A sex‐specific stratification of human CRC patients corroborated the data obtained in mice and revealed that reduced tumor cell‐intrinsic nuclear STAT1 protein expression is a poor prognostic factor in men but not in women. These data demonstrate that epithelial STAT1 is a male‐specific tumor suppressor in CRC of mice and humans.

Effect of rapamycin on gene expression of nuclear factor-κB p65 and STAT-1 in sprague–dawley rats with acute lung injury

Effect of rapamycin on gene expression of nuclear factor-κB p65 and STAT-1 in sprague–dawley rats with acute lung injury

Pharmacologic activation of cholinergic alpha7 nicotinic receptors mitigates depressive-like behavior in a mouse model of chronic stress

BackgroundIt has been shown that chronic stress-induced depression is associated with exaggerated inflammatory response in the brain. Alpha7 nicotinic acetylcholine receptors (α7nAChRs) regulate the cholinergic anti-inflammatory pathway, but the role of cholinergic signaling and α7nAChR in chronic stress has not yet been examined.MethodsIn this study, we used a well-documented model of depression in which mice were exposed to 6 h of restraint stress for 21 consecutive days. Components of cholinergic signaling and TLR4 signaling were analyzed in the hippocampus. The main targets of neuroinflammation and neuronal damage were also evaluated after a series of tests for depression-like behavior.ResultsChronic restraint stress (CRS) induced alterations in components of central cholinergic signaling in hippocampus, including increases in choline acetyltransferase protein expression and decreases in nuclear STAT3 signaling. CRS also increased TLR4 signaling activity, interleukin-1β, and tumor necrosis factor-α expression, microglial activation, and neuronal morphologic changes. Cholinergic stimulation with the α7nAChR agonist DMXBA significantly alleviated CRS-induced depressive-like behavior, neuroinflammation, and neuronal damage, but these effects were abolished by the selective α7nAChR antagonist α-bungarotoxin. Furthermore, activation of α7nAChRs restored the central cholinergic signaling function, inhibited TLR4-mediated inflammatory signaling and microglial activity, and increased the number of regulatory T cells in the hippocampus.ConclusionsThese findings provide evidence that α7nAChR activation mitigates CRS-induced neuroinflammation and cell death, suggesting that α7nAChRs could be a new therapeutic target for the prevention and treatment of depression.

SHP2 associates with nuclear localization of STAT3: significance in progression and prognosis of colorectal cancer

Tyrosine phosphatase SHP2, encoded by PTPN11, has been implicated in many physiologic and pathologic processes in neoplastic progression. However, controversies are emerging from many studies, indicating SHP2 has a dual role in different types of tumors. We aimed to explore the role of SHP2 in progression and prognosis of colorectal cancer (CRC). SHP2 inhibited CRC cell proliferation and migration, and the phosphorylation of STAT3 was negatively regulated by SHP2 in CRC. SHP2 and nuclear STAT3 were examined in 270 CRC tissues. SHP2 was significantly correlated with nuclear STAT3 (Spearman’s rho = −0.408, P ≤ 0.001). Based on Cox regression analysis, patients with high levels of SHP2 and low levels of nuclear STAT3 had longer disease-specific survival (DSS) (HR, 0.362; 95% CI, 0.165–0.794) and disease-free survival (DFS) (HR, 0.447; 95% CI, 0.227–0.877). Further, low levels of SHP2 and high levels of nuclear STAT3 were independently associated with adverse outcomes in the whole cohort (DFS; HR, 2.353; 95% CI, 1.199–4.619). These results suggest that combination of SHP2 and nuclear STAT3 is a strong prognostic predictor in CRC.

Investigation of the pronounced erythropoietin-induced reduction in hyperglycemia in type 1-like diabetic rats.

Erythropoietin (EPO) is known to stimulate erythropoiesis after binding with its specific receptor. In clinics, EPO is widely used in hemodialyzed patients with diabetes. However, changes in the expression of the erythropoietin receptor (EPOR) under diabetic conditions are still unclear. Therefore, we investigated EPOR expression both in vivo and in vitro. Streptozotocin-induced type 1-like diabetic rats (STZ rats) were used to evaluate the blood glucose-lowering effects of EPO. The expression and activity of the transducer and activator of transcription 3 (STAT3), the potential signaling molecule, was investigated in cultured rat skeletal myoblast (L6) cells incubated in high-glucose (HG) medium to mimic the in vivo changes. The EPO-induced reduction in hyperglycemia was more pronounced in diabetic rats. The increased EPOR expression in the soleus muscle of diabetic rats was reversed by the reduction in hyperglycemia. Glucose uptake was also increased in high-glucose (HG)-treated L6 cells. Western blotting results indicated that the EPO-induced hyperglycemic activity was enhanced mainly through an increase in EPOR expression. Increased EPOR expression was associated with the enhanced nuclear expression of STAT3 in HG-exposed L6 cells. In addition, treatment with siRNA specific to STAT3 reversed the increased expression of EPOR observed in these cells. Treatment with Stattic at a dose sufficient to inhibit STAT3 reduced the expression level of EPOR in STZ rats. In conclusion, the increased expression of EPOR by hyperglycemia is mainly associated with an augmented expression of nuclear STAT3, which was identified both in vivo and in vitro in the present study.

The promotion of nephropathy by Porphyromonas gingivalis lipopolysaccharide via toll-like receptors

BackgroundRecently, we reported that toll-like receptor (TLR)2 and TLR4 localized on the glomerular endothelium in the glomeruli of streptozotocin (STZ)-induced type 1 diabetic mice and high fat diet feed-induced type 2 diabetic mice, and that periodontal pathogen Porphyromonas gingivalis LPS (Pg-LPS) administration lowered the survival rate of diabetic mice. The present study aims to examine the effect of TLR4 blocking on the suppression of Pg-LPS-induced diabetic nephropathy.MethodsThe survival rate and morphological/biochemical features for streptozotocin-induced diabetic mice with Pg-LPS and TLR4 blocker eritoran administration were investigated by reporter gene assay, urine and blood analysis, immunohistochemistry, and real time-PCR.Results and ConclusionsAll of the diabetic mice administered Pg-LPS were euthanized within the survival period of almost all of the diabetic mice. The blood urea nitrogen and creatinine, expression of TLR2 and TGF-b, and type 1 collagen accumulation, in the diabetic mice increased significantly with the Pg-LPS administration. In spite of the limited TLR4 activation with Pg-LPS, the TLR4 blocker eritoran decreased blood urea nitrogen and creatinine, and raised the survival rate of the Pg-LPS-administered diabetic mice slightly. The high expression levels of TLR2, TGF-b, and type 1 collagen in Pg-LPS-administered diabetic mice decreased with eritoran. Nuclear STAT3 which enhances TLR2 expression was detected in the TLR2-expressing glomeruli of diabetic mice. The TLR2 and STAT3 gene expression increased by the Pg-LPS administration but decreased with eritoran. These may suggest that Pg-LPS-induced diabetic nephropathy is mainly dependent on TLR2 signaling on glomerular endothelial cells, and that TLR4 blocker eritoran may play a role to slow the progress of diabetic nephropathy.

Brief Report: Group 3 Innate Lymphoid Cells in Human Enthesis.

Group 3 innate lymphoid cells (ILC3s) play a pivotal role in barrier tissues such as the gut and the skin, two important sites of disease in spondyloarthritis (SpA). This study was undertaken to investigate whether normal or injured human enthesis, a key target tissue in early SpA, harbors ILC3s in entheseal soft tissue and adjacent perientheseal bone. Interspinous ligament and spinous process bone from donors with no systemic inflammatory disease were collected, enzymatically digested, and immunophenotyped. The immunologic profile of entheseal cells was examined, and the transcriptional profile of sorted ILC3s was compared to that of ILC3s isolated from SpA synovial fluid (SF). To assess the ability of entheseal tissue to produce interleukin-17 (IL-17) and IL-22, entheseal digests were stimulated with IL-23 and IL-1β. Osteoarthritic and ruptured Achilles tendon tissue was examined histologically. The proportion of ILCs in human entheseal soft tissue was higher than that in peripheral blood (P = 0.008); entheseal soft tissue and perientheseal bone both had a higher proportion of NKp44+ ILC3s (P = 0.001 and P = 0.043, respectively). Studies of retinoic acid receptor-related orphan nuclear receptor γt (RORγt), STAT3, and IL-23 receptor transcript expression validated the entheseal ILC3 phenotype. Cytokine transcript expression was similar in ILC3s isolated from enthesis and from SpA SF. Stimulation of normal entheseal digests with IL-23/IL-1β led to up-regulation of IL-17A transcript, and histologic examination of injured/damaged entheses revealed the presence of RORγt-expressing cells. This work shows that human enthesis harbors a resident population of ILC3s, with the potential to participate in the pathogenesis of SpA.

A case of meningeal myxoid solitary fibrous tumor/hemangiopericytoma with unique NAB2-STAT6 fusion gene and symptomatic intratumoral hemorrhage

We experienced a case of meningeal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) with symptomatic intratumoral hemorrhage in a 67-year-old Japanese woman. Her chief complaints were sudden onset of motor aphasia and right hemiparesis. Brain computed tomography showed the hemorrhagic mass adjacent to the superior sagittal sinus. The mass was resected and pathological examination of the specimen revealed a tumor that is rich in vessels and accompanied with intratumoral hemorrhage. Short spindle tumor cells were proliferating with myxoid stroma. Tumor cells appeared to be arranged around the vessels and sometimes attached to the vessel wall directly. Although hyalinization of the vessel wall was observed, neither patternless pattern nor staghorn vessels were seen. Immunohistochemistry revealed that the tumor cells were positive for both CD34 and nuclear STAT6. Moreover, gene analyses revealed unique NAB2-STAT6 fusion. Immunohistochemical findings and fusion-gene analyses enabled us to make the definite diagnosis of meningeal myxoid SFT/HPC. The present case showed the three unique features such as clinically symptomatic intratumoral hemorrhage at the onset, rare variant of myxoid SFT/HPC, and unique NAB2-STAT6 fusion.

MRTF-A mediated FN and ICAM-1 expression in AGEs-induced rat glomerular mesangial cells via activating STAT5

Advanced glycation end products (AGEs), formed at an accelerated rate under diabetes, play a role in inflammation and fibrosis in mesangial areas in diabetic nephropathy (DN). However, the transcriptional modulator that mediates the cellular response to AGEs remains largely obscure. Our goal was to determine whether myocardin-related transcription factor (MRTF)-A, a key protein involved in the transcriptional regulation of smooth muscle cell phenotype, was responsible for the glomerular mesangial cells (GMCs) injury by AGEs, and, if so, how MRTF-A promoted mesangial dysfunction initiated by AGEs. In this study, MRTF-A was activated by AGEs in terms of protein expression and nuclear translocation in rat GMCs. MRTF-A overexpression synergistically enhanced the induction of FN and ICAM-1 by AGEs. In contract, depletion of MRTF-A abrogated the pathogenic program triggered by AGEs. Then, by interfering with MRTF-A, STAT1, STAT3 and STAT5 nuclear translocation were observed and we screened out STAT5, which was decreased obviously when MRTF-A depleted. Further investigation showed that MRTF-A interacted with STAT5 and promoted its nuclear accumulation and transcriptional activity. Therefore, our present findings suggested a role of MRTF-A in AGEs-induced GMCs injury, and further revealed that the underlying molecular mechanism was related to activating the nuclear factor STAT5.

Microwell Geometry Modulates Interleukin-6 Secretion in Human Mesenchymal Stem Cells

ABSTRACTThe therapeutic effect of mesenchymal stem cells (MSCs) has been investigated in various clinical applications, in which their functional benefits are mainly attributed to the secretion of soluble factors. The enhancement of their therapeutic potential by physical and chemical properties of cell culture substrate is a safe and effective strategy, since they are highly sensitive to their microenvironment such as the elasticity and surface topography. In this study, we demonstrated that the geometry of polymeric substrate regulated the interleukin-6 (IL-6) secretion of human adipose derived MSCs. Polystyrene substrates comprising arrays of square-shaped (S50) or round-shaped (R50) microwells (side length or diameter of 50 μm and depth of 10 μm) were prepared by injection molding. Cellular apoptototic rate of MSCs was not affected by the microwell geometry, while the upregulated secretion of IL-6 and the enhancement of nuclear transcription factor STAT3 were detected in MSCs seeded on S50 substrate. The geometry-dependent modulatory effect was highly associated with ROCK signaling cascade. The inhibition of ROCK abolished the disparity in IL-6 secretion. These findings highlight the possibility to steer the secretion profile of stem cells via microwell geometry in combination with the manipulation of ROCK signaling pathway.

Solitary fibrous tumour of the tongue: a series of four cases.

Solitary fibrous tumour is a soft tissue tumour of mesenchymal origin. It was first described in the pleura and has since been reported in many anatomical locations. Thirteen cases in the tongue have hitherto been reported. A positive CD34 result has traditionally been used to confirm the diagnosis, although this is often non-specific to solitary fibrous tumour. To date, nuclear STAT6 expression has not been reported in solitary fibrous tumour of the tongue. This paper presents a further four cases of solitary fibrous tumour of the tongue, the largest series to date. Clinical, histopathological and immunohistochemical findings are detailed, including nuclear STAT6 expression. All four cases were positive for CD34; two cases showed nuclear expression of STAT6. The tumours were excised completely and there have been no recurrences in at least one year. Solitary fibrous tumour should be considered as a differential diagnosis for tongue swellings, with the potential to recur.