Acid-sensing receptor GPR4 plays a crucial role in lymphatic cancer metastasis.

Cancer tissues exhibit an acidic microenvironment owing to the accumulation of protons and lactic acid produced by cancer and inflammatory cells. To examine the role of an acidic microenvironment in lymphatic cancer metastasis, gene expression profiling was conducted using human dermal lymphatic endothelial cells (HDLECs) treated with a low pH medium. Microarray and gene set enrichment analysis revealed that acid treatment induced the expression of inflammation-related genes in HDLECs, including genes encoding chemokines and adhesion molecules. Acid treatment-induced chemokines C-X3-C motif chemokine ligand 1 (CX3CL1) and C-X-C motif chemokine ligand 6 (CXCL6) autocrinally promoted the growth and tube formation of HDLECs. The expression of vascular cell adhesion molecule 1 (VCAM-1) increased in HDLECs after acid treatment in a time-dependent manner, which, in turn, enhanced their adhesion to melanoma cells. Among various acid-sensing receptors, HDLECs basally expressed G protein-coupled receptor 4 (GPR4), which was augmented under the acidic microenvironment. The induction of chemokines or VCAM-1 under acidic conditions was attenuated by GPR4 knockdown in HDLECs. In addition, lymph node metastases in a mouse melanoma model were suppressed by administering an anti-VCAM-1 antibody or a GPR4 antagonist. These results suggest that an acidic microenvironment modifies the function of lymphatic endothelial cells via GPR4, thereby promoting lymphatic cancer metastasis. Acid-sensing receptors and their downstream molecules might serve as preventive or therapeutic targets in cancer.

Loss of Dec1 inhibits alcohol-induced hepatic lipid accumulation and circadian rhythm disorder.

Chronic alcohol exposure increases liver damage such as lipid accumulation and hepatitis, resulting in hepatic cirrhosis. Chronic alcohol intake is known to disturb circadian rhythms in humans and animals. DEC1, a basic helix-loop-helix transcription factor, plays an important role in the circadian rhythm, inflammation, immune responses, and tumor progression. We have previously shown that Dec1 deficiency inhibits stresses such as periodontal inflammation and perivascular fibrosis of the heart. However, the significance of Dec1 deficiency in chronic alcohol consumption remains unclear. In the present study, we investigated whether the biological stress caused by chronic alcohol intake is inhibited in Dec1 knockout mice. We treated control and Dec1 knockout mice for three months by providing free access to 10% alcohol. The Dec1 knockout mice consumed more alcohol than control mice, however, we observed severe hepatic lipid accumulation and circadian rhythm disturbance in control mice. In contrast, Dec1 knockout mice exhibited little effect on these outcomes. We also investigated the expression of peroxisome proliferator-activated receptors (PPARs) and AMP-activated protein kinase (AMPK), which are involved in the regulation of fatty acid metabolism. Immunohistochemical analysis revealed increases of phosphorylation AMPK and PPARa but decreases PPARg in Dec1 knockout mice compared to that in control mice. This indicates a molecular basis for the inhibition of hepatic lipid accumulation in alcohol-treated Dec1 knockout mice. These results suggest a novel function of Dec1 in alcohol-induced hepatic lipid accumulation and circadian rhythm disorders.

Differential immunohistochemical expression of DEC1, CK­1ε, and CD44 in oral atypical squamous epithelium and carcinoma in situ.

Presence of nuclear atypia during histological investigation is often a cause of concern for pathologists while identifying tumor and non­tumor cells in a biopsy sample of oral mucosa. Nuclear atypia is observed in severe inflammation, ulcers and reactive changes. Therefore, additional methods, such as immunohistochemistry, may help precise diagnosis. When the atypia is suggestive of tumorous or reactive origin, the lesion is diagnosed as atypical squamous epithelium (ASE). When there is severe nuclear atypia in the mucosa, such as in disorders of nuclear polarity, large nuclei, and clear nucleolus, the lesion is diagnosed as carcinoma in situ (CIS). However, it is not easy to distinguish ASE and CIS using hematoxylin and eosin staining. The present study aimed to distinguish ASE from CIS using immunohistochemistry. A total of 32 biopsy samples of either ASE or CIS cases were selected and the level of casein kinase 1ε (CK­1ε), differentiated embryonic chondrocyte gene 1 (DEC1), proliferating cell nuclear antigen (PCNA) and CD44, which are four protein markers which have been previously linked to cancer progression, were analyzed. CK­1ε and CD44 expression was higher in CIS samples than in ASE samples. However, DEC1 expression was lower in CIS samples than in ASE samples. PCNA expression was not markedly different between the two groups. Additionally, it was found that DEC1­overexpressing cells had decreased levels of CK­1ε and CD44 compared with control cells, while CK­1ε­overexpressing cells had relatively unchanged levels of CD44, DEC1 and PCNA. These results suggested that DEC1 negatively regulates the expression of CK­1ε and CD44. Thus, DEC1, CK­1ε, and CD44 were identified as mechanistically linked and clinically relevant protein biomarkers, which could help distinguish ASE and CIS.

Exposure to Cigarette Smoke Enhances Pneumococcal Transmission Among Littermates in an Infant Mouse Model.

Streptococcus pneumoniae, one of the most common commensal pathogens among children, is spread by close contact in daycare centers or within a family. Host innate immune responses and bacterial virulence factors promote pneumococcal transmission. However, investigations into the effects of environmental factors on transmission have been limited. Passive smoking, a great concern for children's health, has been reported to exacerbate pneumococcal diseases. Here, we describe the effect of cigarette smoke exposure on an infant mouse model of pneumococcal transmission. Our findings reveal that the effect of cigarette smoke exposure significantly promotes pneumococcal transmission by enhancing bacterial shedding from the colonized host and by increasing susceptibility to pneumococcal colonization in the new host, both of which are critical steps of transmission. Local inflammation, followed by mucosal changes (such as mucus hypersecretion and disruption of the mucosal barrier), are important underlying mechanisms for promotion of transmission by smoke exposure. These effects were attributable to the constituents of cigarette smoke rather than smoke itself. These findings provide the first experimental evidence of the impact of environmental factors on pneumococcal transmission and the mechanism of pathogenesis.

Acidic microenvironment induction of interleukin-8 expression and matrix metalloproteinase-2/-9 activation via acid-sensing ion channel 1 promotes breast cancer cell progression.

The cancer microenvironment exhibits local acidosis compared with the surrounding normal tissue. Many reports have shown that acidosis accelerates the invasiveness and metastasis of cancer, yet the underlying molecular mechanisms remain unclear. In the present study, we focused on acid-induced functional changes through acid receptors in breast cancer cells. Acidic treatment induced interleukin (IL)-8 expression in MDA-MB-231 cells and promoted cell migration and invasion. The acidic microenvironment elevated matrix metalloproteinase (MMP)-2 and MMP-9 activity, and addition of IL-8 had similar effects. However, inhibition of IL-8 suppressed the acid-induced migration and invasion of MDA-MB-231 cells. MDA-MB-231 cells express various acid receptors including ion channels and G protein-coupled receptors. Interestingly, acidic stimulation increased the expression of acid-sensing ion channel 1 (ASIC1), and acid-induced IL-8 was significantly decreased by ASIC1 knockdown. Moreover, phosphorylation of nuclear factor (NF)-κB was induced by acidic treatment, and inhibition of NF-κB activation reduced acid-induced IL-8 expression. These results suggest that IL-8 induction by an acidic microenvironment promotes breast cancer development and that ASIC1 might be a novel therapeutic target for breast cancer metastasis.

The Gain-of-Function Mutation p53R248W Suppresses Cell Proliferation and Invasion of Oral Squamous Cell Carcinoma through the Down-Regulation of Keratin 17.

Keratin 17 (KRT17) expression promotes the proliferation and invasion of oral squamous cell carcinoma (OSCC), and mutations in TP53 have been reported in 65% to 85% of OSCC cases. We studied the correlation between KRT17 expression and TP53 mutants. Ca9-22 cells, which exhibit low KRT17 expression, carried mutant p53 (p53R248W) and p53R248W knockdown promoted KRT17 expression. p53R248W knockdown in Ca9-22 cells promoted migration and invasion activity. In contrast, in HSC3 cells, which have p53 nonsense mutations and exhibit high KRT17 expression, the overexpression of p53R248W decreased KRT17 expression, cell size, proliferation, and migration and invasion activities. In addition, p53R248W significantly suppressed MMP2 mRNA expression and enzyme activity. Moreover, s.c. and orthotopic xenografts were generated from p53R248W- or p53R248Q-expressing HSC3 cells. Tumors formed from p53R248W-expressing HSC3 cells grew more slowly and had a lower Ki-67 index than those derived from the control or p53R248Q-expressing HSC3 cells. Finally, the survival rate of the mice inoculated with p53R248W-expressing HSC3 cells was significantly higher than that of the control mice. These results indicate that the p53R248W mutant suppresses proliferation and invasion activity through the suppression of KRT17 expression. We propose that OSCC with p53R248W-expressing cells may be classified as a new OSCC type that has a good prognosis.

Suppression of MKL1 promotes adipocytic differentiation and reduces the proliferation of myxoid liposarcoma cells.

Myxoid liposarcoma (MLS) is thought to occur due to defective adipocytic differentiation in mesenchymal stem cells. A promising strategy for MLS treatment is the prevention of sarcomagenesis by promoting the terminal differentiation of MLS cells into adipocytes. Previous studies have reported that the suppression of megakaryoblastic leukemia 1 (MKL1) expression induces adipocytic differentiation in preadipocyte cell lines. The present study aimed to investigate the effects of MKL1 suppression on MLS cells. In the present study, MKL1 knockdown was demonstrated to promote the adipocytic differentiation of an MLS-derived cell line, designated 1955/91, under adipogenic conditions. This suggests that therapeutic targeting of the MKL1-associated molecular pathway has potential as a promising method of MLS treatment. However, the induction of adipogenesis by MKL knockdown was incomplete, and Oil Red O staining indicated that intracellular lipid droplets were only sporadically generated. Conversely, MKL1 knockdown reduced the growth of the MLS cells. As adipocytic differentiation in vitro requires cellular confluence, the decreased growth rate of the MLS cells following MKL1 knockdown could be attributed to the incomplete induction of adipogenesis. Translocated in liposarcoma-CCAAT/enhancer-binding protein homologous protein (TLS-CHOP) is an MLS-specific oncoprotein that is thought to play key roles in sarcomagenesis and the suppression of adipocytic differentiation. However, the results of western blotting analyses suggest that TLS-CHOP has limited effects on MKL1 expression in MLS cells and that MKL1 knockdown hardly affects TLS-CHOP expression. Thus, it is postulated that the inhibitory effect of TLS-CHOP on adipogenesis is not associated with MKL1 expression. However, MKL1 and the molecular pathway involving MKL1 appear to be attractive targets for the differentiation therapy of MLS.

Potential Role of DEC1 in Cervical Cancer Cells Involving Overexpression and Apoptosis.

Basic helix-loop-helix (BHLH) transcription factors differentiated embryonic chondrocyte gene 1 (DEC1) and gene 2 (DEC2) regulate circadian rhythms, apoptosis, epithelial mesenchymal transition (EMT), invasions and metastases in various kinds of cancer. The stem cell markers SOX2 and c-MYC are involved in the regulation of apoptosis and poor prognosis. In cervical cancer, however, their roles are not well elucidated yet. To determine the function of these genes in human cervical cancer, we examined the expression of DEC1, DEC2, SOX2 and c-MYC in human cervical cancer tissues. In immunohistochemistry, they were strongly expressed in cancer cells compared with in non-cancerous cells. Notably, the strong rate of DEC1 and SOX2 expressions were over 80% among 20 cases. We further examined the roles of DEC1 and DEC2 in apoptosis. Human cervical cancer HeLa and SiHa cells were treated with cisplatin-HeLa cells were sensitive to apoptosis, but SiHa cells were resistant. DEC1 expression decreased in the cisplatin-treated HeLa cells, but had little effect on SiHa cells. Combination treatment of DEC1 overexpression and cisplatin inhibited apoptosis and affected SOX2 and c-MYC expressions in HeLa cells. Meanwhile, DEC2 overexpression had little effect on apoptosis and on SOX2 and c-MYC expressions. We conclude that DEC1 has anti-apoptotic effects and regulates SOX2 and c-MYC expressions on apoptosis.

MicroRNA 200b promotes mesenchymal-to-epithelial transition in anaplastic thyroid carcinoma.

Anaplastic thyroid cancer (ATC) remains a cancer with one of the worst prognoses, despite novel targeted therapies. The median survival rate has not improved for decades. Epithelial-to-mesenchymal transition (EMT) is a crucial step in physiological processes and in cancer progression, but the underlying mechanisms are not yet fully understood. The current study examined the role of microRNA (miR)-200b in mesenchymal-to-epithelial transition in ATC. Total RNA and miR isolation were performed from ATC cell lines transfected with a miR-200b mimic. After miR-200b mimic transfection, expression levels of E-cadherin, vimentin and zinc finger E-box binding homeobox 1 (ZEB1) were confirmed by reverse transcription-quantitative PCR and western blotting. Additionally, cell migration was evaluated using miR-200b mimic and scrambled negative control-transfected cells. A total of 14 human ATC and 15 non-cancerous human thyroid tissues were immunohistochemically stained and scored as controls for E-cadherin, vimentin and ZEB1. In ATC tissues and cell lines, the mesenchymal marker ZEB1 was significantly upregulated and the epithelial marker E-cadherin was significantly downregulated. Additionally, the mesenchymal marker vimentin was significantly upregulated in ATC tissues and in one ATC cell line. MiR-200b mimic transfection significantly increased vimentin and ZEB1 expression, but E-cadherin expression remained below the measurement sensitivity. Furthermore, miR-200b overexpression decreased cell migration. The current study suggested that miR-200b may regulate the expression levels of mesenchymal markers such as vimentin and ZEB1 in ATC and may promote mesenchymal-to-epithelial transition.

PD-L1 expression correlated with p53 expression in oral squamous cell carcinoma.

BACKGROUND: Programmed cell death ligand 1 (PD-L1) is an immune checkpoint molecule that attenuates the immune response. PD-L1 contributes to failed antitumor immunity; thereby, blockade of PD-L1 with monoclonal antibody enhances the immune response. Recently, it was reported that PD-L1 was regulated by protein 53 (p53). Besides, cytokeratin 17 (CK17) is thought to be a diagnostic marker of oral squamous cell carcinoma (OSCC). Our aim was to evaluate the correlation between the immunohistochemical expression of PD-L1, p53 and CK17 with clinicopathological characteristics and disease-specific survival in patients with OSCC. METHODS: A total of 48 patients with OSCC were included in this study. Immunohistochemical staining was performed to evaluate the correlation among the expressions of PD-L1, p53 and CK17, and furthermore the correlation among various clinicopathological factors, PD-L1, p53 and CK17. RESULTS: The positive rate of p53, CK17, PD-L1 (tumor cells) and PD-L1 (tumor-infiltrating lymphocytes) was 63.2%, 91.7%, 48.9% and 57.1%. A statistically significant correlation between p53 expression and T stage and TNM stage (p = 0.049, p = 0.03, respectively) was observed. Also, a statistically significant correlation between p53 and PD-L1 (TCs) expression (p = 0.0009) was observed. Five-year disease-specific survival rate was not significantly correlated with gender, TNM stage, p53 expression, PD-L1 expression and CK17 expression. CONCLUSION: The expression of p53 and PD-L1 shows significantly positive correlation in oral squamous cell carcinoma in tumor cells. Also, a significant correlation between p53 expression and T stage and TNM stage was observed. No other significant correlation between PD-L1 staining or CK17 and clinical or pathologic characteristics was identified.

A novel therapeutic approach for anaplastic thyroid cancer through inhibition of LAT1.

A novel therapeutic approach is urgently needed for patients with anaplastic thyroid cancer (ATC) due to its fatal and rapid progress. We recently reported that ATC highly expressed MYC protein and blocking of MYC through its selective inhibitor, JQ1, decreased ATC growth and improved survival in preclinical models. One of the important roles of MYC is regulation of L-neutral amino acid transporter 1 (LAT1) protein and inhibition of LAT1 would provide similar anti-tumor effect. We first identified that while the human ATC expresses LAT1 protein, it is little or not detected in non-cancerous thyroidal tissue, further supporting LAT1 as a good target. Then we evaluated the efficacy of JPH203, a LAT1 inhibitor, against ATC by using the in vitro cell-based studies and in vivo xenograft model bearing human ATC cells. JPH203 markedly inhibited proliferation of three ATC cell lines through suppression of mTOR signals and blocked cell cycle progression from the G0/G1 phase to the S phase. The tumor growth inhibition and decrease in size by JPH203 via inhibition of mTOR signaling and G0/G1 cell cycle associated proteins were further confirmed in xenograft models. These preclinical findings suggest that LAT1 inhibitors are strong candidates to control ATC, for which current treatment options are highly limited.

Dec1 Deficiency Suppresses Cardiac Perivascular Fibrosis Induced by Transverse Aortic Constriction.

Cardiac fibrosis is a major cause of cardiac dysfunction in hypertrophic hearts. Differentiated embryonic chondrocyte gene 1 (Dec1), a basic helix-loop-helix transcription factor, has circadian expression in the heart; however, its role in cardiac diseases remains unknown. Therefore, using Dec1 knock-out (Dec1KO) and wild-type (WT) mice, we evaluated cardiac function and morphology at one and four weeks after transverse aortic constriction (TAC) or sham surgery. We found that Dec1KO mice retained cardiac function until four weeks after TAC. Dec1KO mice also revealed more severely hypertrophic hearts than WT mice at four weeks after TAC, whereas no significant change was observed at one week. An increase in Dec1 expression was found in myocardial and stromal cells of TAC-treated WT mice. In addition, Dec1 circadian expression was disrupted in the heart of TAC-treated WT mice. Cardiac perivascular fibrosis was suppressed in TAC-treated Dec1KO mice, with positive immunostaining of S100 calcium binding protein A4 (S100A4), alpha smooth muscle actin (αSMA), transforming growth factor beta 1 (TGFß1), phosphorylation of Smad family member 3 (pSmad3), tumor necrosis factor alpha (TNFα), and cyclin-interacting protein 1 (p21). Furthermore, Dec1 expression was increased in myocardial hypertrophy and myocardial infarction of autopsy cases. Taken together, our results indicate that Dec1 deficiency suppresses cardiac fibrosis, preserving cardiac function in hypertrophic hearts. We suggest that Dec1 could be a new therapeutic target in cardiac fibrosis.

Differential expression of claudin­4, occludin, SOX2 and proliferating cell nuclear antigen between basaloid squamous cell carcinoma and squamous cell carcinoma.

Basaloid squamous cell carcinomas (BSCCs) in oral lesions are extremely rare, and the histology is not well understood. Histologically, they are often similar to conventional squamous cell carcinoma (SCC). The present study was designed with an aim to distinguish BSCC from SCC using claudin­4, occludin, SRY­box 2 (SOX2) and proliferating cell nuclear antigen (PCNA) immunoreactivities and staining patterns. Three BSCCs (with abundant, with moderate, and without squamous components) specimens and 20 SCC specimens were selected for comparison of their immunoreactivity. These specimens were stained with claudin­4, occludin, SOX2 and PCNA. In addition to histological analysis, the expression of claudin­4, occludin and PCNA was determined in oral cancer HSC2 and HSC3 cells with or without SOX2 overexpression, and cell proliferation was determined by XTT assay. Claudin­4 had strong and occludin had weak immunoreactivity as detected in the membrane of squamous components of BSCC but not in cancer cells. No obvious detection of squamous components and cancer cells were observed in SCC. SOX2 and PCNA immunoreactivities in SCC had dot­like staining patterns in the nuclei of partial and marginal cancer cells. In contrast, in BSCCs, SOX2 and PCNA had diffuse staining patterns in almost all cancer cells. SOX2 overexpression had little effect on the expression levels of claudin­4, occludin and PCNA. It also had little effect on the cell proliferation of HSC2 and HSC3 cells. Differences in immunoreactivity and staining pattern may be valuable to distinguish between BSCC and SCC in diagnosis.

Smad3 Suppresses Epithelial Cell Migration and Proliferation via the Clock Gene Dec1, Which Negatively Regulates the Expression of Clock Genes Dec2 and Per1.

Smad3 has circadian expression; however, whether Smad3 affects the expression of clock genes is poorly understood. Here, we investigated the regulatory mechanisms between Smad3 and the clock genes Dec1, Dec2, and Per1. In Smad3 knockout mice, the amplitude of locomotor activity was decreased, and Dec1 expression was decreased in the suprachiasmatic nucleus, liver, kidney, and tongue compared with control mice. Conversely, Dec2 and Per1 expression was increased compared with that of control mice. In Smad3 knockout mice, immunohistochemical staining revealed that Dec1 expression decreased, whereas Dec2 and Per1 expression increased in the endothelial cells of the kidney and liver. In NIH3T3 cells, Smad3 overexpression increased Dec1 expression, but decreased Dec2 and Per1 expression. In a wound-healing experiment that used Smad3 knockout mice, Dec1 expression decreased in the basal cells of squamous epithelium, promoting wound healing of the mucosa. Finally, the migration and proliferation of Smad3 knockdown squamous carcinoma cells was suppressed by Dec1 overexpression but was promoted by Dec2 overexpression. Dec1 overexpression decreased E-cadherin and proliferating cell nuclear antigen expression, whereas these expression levels were increased by Dec2 overexpression. These results suggest Smad3 is relevant to circadian rhythm and regulates cell migration and proliferation through Dec1, Dec2, and Per1 expression.

Impact of heart-specific disruption of the circadian clock on systemic glucose metabolism in mice.

The daily rhythm of glucose metabolism is governed by the circadian clock, which consists of cell-autonomous clock machineries residing in nearly every tissue in the body. Disruption of these clock machineries either environmentally or genetically induces the dysregulation of glucose metabolism. Although the roles of clock machineries in the regulation of glucose metabolism have been uncovered in major metabolic tissues, such as the pancreas, liver, and skeletal muscle, it remains unknown whether clock function in non-major metabolic tissues also affects systemic glucose metabolism. Here, we tested the hypothesis that disruption of the clock machinery in the heart might also affect systemic glucose metabolism, because heart function is known to be associated with glucose tolerance. We examined glucose and insulin tolerance as well as heart phenotypes in mice with heart-specific deletion of Bmal1, a core clock gene. Bmal1 deletion in the heart not only decreased heart function but also led to systemic insulin resistance. Moreover, hyperglycemia was induced with age. Furthermore, heart-specific Bmal1-deficient mice exhibited decreased insulin-induced phosphorylation of Akt in the liver, thus indicating that Bmal1 deletion in the heart causes hepatic insulin resistance. Our findings revealed an unexpected effect of the function of clock machinery in a non-major metabolic tissue, the heart, on systemic glucose metabolism in mammals.

Levels of serum-circulating angiogenic factors within 1 week prior to delivery are closely related to conditions of pregnant women with pre-eclampsia, gestational hypertension, and/or fetal growth restriction.

AIM: We aimed to investigate maternal serum angiogenic marker profiles within 1 week prior to delivery in cases of gestational hypertension (GH), pre-eclampsia (PE), and/or fetal growth restriction (FGR) with different clinical conditions. METHODS: We enrolled 165 women with singleton pregnancy. The participants were classified based on three characteristics: (i) proteinuria (GH and PE); (ii) FGR (PE with FGR [PE + FGR], PE alone, and FGR alone); and (iii) onset (early onset PE [EO PE] and late-onset PE [LO PE]). All sera were obtained within 1 week prior to delivery, and soluble fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin (sEng), and placental growth factor (PlGF) were measured with enzyme-linked immunosorbent assay. RESULTS: (i) In PE, a significantly increased sFlt-1, sEng, and sFlt-1 to PlGF ratio (sFlt-1/PlGF) and significantly decreased PlGF were observed compared with GH and Term control, whereas in GH, only sFlt-1/PlGF was significantly higher than Term control. (ii) In PE + FGR, similar changes were more markedly shown compared with PE alone. The FGR alone group exhibited similar tendencies as PE, although significant differences were found in PlGF and sEng levels. (iii) In EO PE, significant changes were observed in all factors compared with LO PE or Term control, while no significant change in PlGF levels was observed between LO PE and Term control. CONCLUSION: We demonstrated that the levels of circulating angiogenic factors just before delivery are correlated with the severity of hypertensive disorders of pregnancy and FGR. Profiling these specific markers may contribute to better understanding of the clinical conditions in individual patients and their pathogenesis.

Smad3 and Bmal1 regulate p21 and S100A4 expression in myocardial stromal fibroblasts via TNF-α.

Bmal1, a clock gene, is associated with depression, hypertrophy, metabolic syndrome and diabetes. Smad3, which is involved in the TGF-ß signaling pathway, plays an important role in the regulation of tumor progression, fibrosis, obesity and diabetes. Our previous report showed that Smad3 has circadian expression in mouse livers. In the current study, we focused on the heart, especially on the myocardial stromal fibroblasts because the roles of Bmal1 and Smad3 in this tissue are poorly understood. Bmal1 and Smad3 have circadian expression in mouse hearts, and their circadian expression patterns were similar. Bmal1 expression decreased in the hearts of whole-body Smad3 knockout mice, whereas Smad3 expression had little effect on heart-specific Bmal1 knockout mice. Both Smad3 knockout and heart-specific Bmal1 knockout mice showed increases in p21, S100A4, CD206 and TNF-α expression in the myocardial stromal fibroblasts and macrophage compared to control mice. We also examined Smad3, Bmal1 and Dec1 expression in human tissue from old myocardial infarctions. Expression of Smad3, Bmal1 and Dec1 decreased in the stromal fibroblasts of tissue from old myocardial infarctions compared to control cases. On the other hand, p21, S100A4 and TNF-α increased in the stromal fibroblasts of tissue from old myocardial infarctions. Furthermore, expression of Smad3, Bmal1 and Dec1 decreased in TNF-α treated-NIH3T3 cells but expression of p21 and S100A4 increased. This new evidence suggests that Smad3 and Bmal1 regulate p21 and S100A4 expression in myocardial stromal fibroblasts through TNF-α.

PRG4 expression in myxoid liposarcoma maintains tumor cell growth through suppression of an antitumor cytokine IL-24.

PRG4 is one of the downstream molecules of the myxoid liposarcoma (MLS)-specific fusion oncoproteins TLS-CHOP and EWS-CHOP. Exogenous PRG4 expression increases the tumorigenicity of cells injected in nude mice. The molecular functions of PRG4 in tumorigenesis and/or tumor progression of MLS cells, however, still remain unclear. In this report, we demonstrated that siRNA-mediated knockdown of PRG4 suppressed the growth of the MLS-derived cell lines 1955/91 and 2645/94. In addition, PRG4 knockdown promoted adipocytic differentiation in 1955/91 cells. Thus, PRG4 may play essential roles in MLS cell growth and have potential as a therapeutic target. On the other hand, our previous study has revealed that TLS-CHOP suppresses expression of an anti-tumor cytokine IL-24, contributing to tumor cell survival. In this study, we found that double knockdown of PRG4 and IL-24 did not inhibit MLS cell growth, and single knockdown of PRG4 remarkably increased IL-24 expression. These results suggest that the growth inhibitory effect of PRG4 knockdown is caused by induction of IL-24 expression, and PRG4 may contribute to maintain MLS cell growth through repression of IL-24 expression.

Refractory Ascites with Liver Fibrosis Developed in Late Phase Allogeneic Hematopoietic Stem Cell Transplantation: Report of Three Patients.

We report cases of three patients of refractory ascites without other fluid retention that occurred around five months after allogeneic hematopoietic stem cell transplantation (allo-HSCT). All three patients expired and postmortem examinations revealed unexpected liver fibrosis lacking histological evidences of graft-versus-host-disease (GVHD). The three patients showed normal hepatic function and size before transplantation. During their clinical courses, serum biochemistry test showed no elevation of hepatic enzymes and bilirubin; however, imaging studies demonstrated hepatic atrophy at the onset of ascites. One of the liver specimens showed bile obstruction, which could be seen in hepatic damage by GVHD. Although ascites resulting from venoocclusive disease in early phase allo-HSCT is well documented, ascites associated with hepatic fibrosis in late phase allo-HCST has not been reported. Further clinico-pathological studies on similar patients should be required to ascertain refractory ascites associated with liver fibrosis after allo-HSCT.

Rhythmic expression of DEC2 protein in vitro and in vivo.

Basic helix-loop-helix (bHLH) transcription factor DEC2 (bHLHE41/Sharp1) is one of the clock genes that show a circadian rhythm in various tissues. DEC2 regulates differentiation, sleep length, tumor cell invasion and apoptosis. Although studies have been conducted on the rhythmic expression of DEC2 mRNA in various tissues, the precise molecular mechanism of DEC2 expression is poorly understood. In the present study, we examined whether DEC2 protein had a rhythmic expression. Western blot analysis for DEC2 protein revealed a rhythmic expression in mouse liver, lung and muscle and in MCF-7 and U2OS cells. In addition, AMP-activated protein kinase (AMPK) activity (phosphorylation of AMPK) in mouse embryonic fibroblasts (MEFs) exhibited a rhythmic expression under the condition of medium change or glucose-depleted medium. However, the rhythmic expression of DEC2 in MEF gradually decreased in time under these conditions. The medium change affected the levels of DEC2 protein and phosphorylation of AMPK. In addition, the levels of DEC2 protein showed a rhythmic expression in vivo and in MCF-7 and U2OS cells. The results showed that the phosphorylation of AMPK immunoreactivity was strongly detected in the liver and lung of DEC2 knockout mice compared with that of wild-type mice. These results may provide new insights into rhythmic expression and the regulation between DEC2 protein and AMPK activity.