Modulation of p75 neurotrophin receptor under hypoxic conditions induces migration and invasion of C6 glioma cells

p75 neurotrophin receptor (p75NTR) has been reported to play important roles in various cancer types. However, the exact mechanism of tumorigenesis involving p75NTR is unknown. In this study, we investigated the relationship between the expression of p75NTR in malignant glioma and the impact on tumor cell migration and invasion. p75NTR and hypoxia-inducible factor-1α (HIF-1α) expression was down-regulated by short-hairpin RNA and up-regulated with expression vectors. By immunohistochemical staining and Western blot analysis, we found that p75NTR was expressed in both human and rat malignant gliomas. Knockdown of p75NTR increased the expression of vimentin, vascular endothelial growth factor, Matrix metalloproteinase 9, and TWIST, and enhanced the invasion and migration abilities assessed by transwell assay in the C6 tumor cells. Inverse expressions of p75NTR and HIF-1α were detected in glioma cell lines under hypoxic conditions, while increased HIF-1α significantly downregulated the expression of p75NTR, suggesting a HIF-1α-p75NTR-EMT pathway that may regulate glioma cells invasion and migration. Downregulation of p75NTR increased phosphorylation of Src, focal adhesion kinase (FAK) and paxillin. Knockdown of p75NTR also dysregulated β-catenin-mediated cell junctions, and up-regulated the expressions of fibronectin and L1CAM in the cell-cell junctions, thus suggesting that p75NTR knockdown contributed to a more aggressive migration phenotype via FAK signaling pathway. Our studies suggested that modulation of p75NTR under hypoxic condition could enhance C6 cells migration and invasion by induction of EMT, and activation of the FAK pathway. The HIF-1α-p75NTR-EMT axis may play a central role in glioma tumorigenesis.

Expression of adhesion molecules and the proliferative activity of carcinosarcoma of the ovary

BACKGROUND

To clarify the mechanism underlying the formation of a sarcomatous component of ovarian carcinosarcoma, we investigated the expression of adhesion molecules and the proliferative activity of carcinosarcomas.

MATERIALS AND METHODS

We immunohistochemically examined the expression of E-cadherin and β-catenin, and the Ki-67 labeling index (Ki-67 LI) in six carcinosarcomas containing endometrioid carcinoma as a carcinomatous component.

RESULTS

The sarcomatous components of the carcinosarcomas did not express E-cadherin or β-catenin. All carcinomatous components expressed these molecules but the expression was reduced compared to that in endometrioid ovarian carcinomas. In five of the six carcinosarcomas, the Ki-67 LI of the sarcomatous component was less than that of the carcinomatous component.

CONCLUSION

The present results suggest that a carcinomatous component transforms more easily than an ordinary endometrioid carcinoma from the viewpoint of the cell adhesion, and cells in a carcinomatous component continuously transform into sarcomatous cells during the growth of carcinosarcoma.

Incomplete epithelial-mesenchymal transition in p16-positive squamous cell carcinoma cells correlates with β-catenin expression

BACKGROUND

The epithelial-mesenchymal transition (EMT) is suggested to be a crucial factor for the development of an invasive and metastatic cell phenotype, which is characterized by down-regulation of epithelial adhesive proteins (e.g. E-cadherin) and induction of mesenchymal proteins (e.g. vimentin). Therefore, there is a great clinical interest to specify this phenotype. Different growth factors induce EMT, such as epithelial growth factor (EGF) and transforming growth factor beta 1 (TGFβ1). The role of EMT in human papilloma virus (HPV)-positive squamous cell carcinoma (SCC) is still not understood. The aim of this study was to investigate the expression pattern in p16-positive and -negative SCC cells of vimentin, β-catenin and E-cadherin after stimulation with growth factors.

MATERIALS AND METHODS

We incubated the p16-positive CERV196 and p16-negative HNSCC22B SCC cell lines with EGF and EGF/TGFβ1 (10 ng/ml) and detected E-cadherin, vimentin and β-catenin by immunocytochemistry and enzyme-linked immunosorbent assay after 5, 24 and 96 h.

RESULTS

We found a low expression of vimentin in all studied tumor cell lines. The negative control of HNSCC22B cells showed a higher intrinsic level of membranous E-cadherin and β-catenin. We found statistically significant EGF/TGFβ1-induced expression of vimentin dependent on incubation time in p16-negative HNSCC22B cells. Particularly in the presence of EGF, we detected an increase of β-catenin and vimentin expression in p16-positive SCC tumor cell lines in addition to induced cell scattering and unexpected expression of E-cadherin.

CONCLUSION

In conclusion, E-cadherin, β-catenin and vimentin expression are important features to characterize EMT-like events. We were able to show incomplete EGF-induced EMT with β-catenin expression in p16-positive SCC. Extended studies are required to investigate the mechanistic role of EMT markers, especially in p16-positive SCC, in order to develop new anti-SCC therapies to block EMT progression.

[The effects of equol on enzymes related to testosterone synthesis and vimentin in the testis of perinatal mice by organ culture in vitro]

OBJECTIVE

To investigate the effects of Equol on genes and protein expression of testosterone synthesis related enzymes and Vimentin in testis of perinatal mice in vitro.

METHODS

Testes were isolated and cultured in infiltrating type rotating device for 72 h. The testes were randomly divided into five groups and treated with Equol (DMSO control, 0.01, 0.10, 1.00, 10.00 μmol/L Equol). Morphological changes were observed by HE staining under optical microscope. Expressions of 3β-hydroxysteroid dehydrogenase (3β-HSD),P450 side-chain cleavage enzyme (P450scc), Vimentin were detected by real-time PCR and immunohistochemistry.

RESULTS

No apparent morphological change in testes was observed compared to control group. The mRNA expression of 3β HSD, P450Scc, Vimentin show no statistical significance(P> 0. 05) in all Equol group, while the protein expressions of 3β-HSD, Vimentin, P450scc increased in 0. 10 μmol/L and decreased in 10.00 μmol/L Equol group.

CONCLUSION

Equol exposure can affect 3β-HSD, P450Scc, Vimentin expression in testes in vitro, means Equol may have potential adverse effects on testosterone production and spermatogenesis.

Clinicopathological characteristics of anaplastic carcinoma of the pancreas with rhabdoid features

Undifferentiated (anaplastic) carcinoma with rhabdoid features is a rare and aggressive subtype of pancreatic carcinoma. Here, we report the clinical, histological, and immunohistochemical phenotypes in six autopsy cases of anaplastic carcinoma with rhabdoid features. The patients ranged between 44 and 76 years of age (median, 61 years) and consisted of four males and two females. All patients except one case died within 3 months of diagnosis, as these tumors were found at an advanced stage and were chemoresistant. At autopsy, tumor masses measuring 4-22 cm in maximum diameter were mainly located in the pancreatic body and tail. Microscopically, all cases showed anaplastic carcinoma with rhabdoid features that were discohesive with round to polygonal eosinophilic cytoplasm with occasional inclusions, and that had vesicular nuclei, and prominent nucleoli. Immunohistochemistry showed that the rhabdoid cells, particularly the inclusions, were strongly positive for pan-cytokeratin (AE1/AE3) and vimentin. Meanwhile, downregulation or aberrant cytoplasmic localization with focal aggregation of E-cadherin, β-catenin, and EMA were frequently observed in the rhabdoid cells. Moreover, the intracytoplasmic inclusions were labeled with selective autophagy-related molecules including p62/SQSTM1, ubiquitin, and kelch-like ECH-associated protein 1 (KEAP1). In addition, nuclear factor erythroid 2-related factor 2 (NRF2) and overexpression of its target molecule multidrug resistance-associated protein 1 (MRP1) were commonly observed in the rhabdoid cells. Therefore, these results suggest that p62-mediated aggregation of ubiquitinated intermediate filaments and membranous proteins is an important phenomenon in the rhabdoid phenotype. Indeed, the ubiquitinated aggregates of p62 and KEAP1 would induce activation of NRF2 and upregulation of MRP1, leading to potential chemoresistance of anaplastic carcinoma with rhabdoid features.

Selenium suppresses lipopolysaccharide-induced fibrosis in peritoneal mesothelial cells through inhibition of epithelial-to-mesenchymal transition

Peritoneal fibrosis resulting from long-term clinical peritoneal dialysis has been the main reason of dropout from peritoneal dialysis. Peritonitis as a common complication of peritoneal dialysis treatment may lead to the occurrences of peritoneal fibrosis. We cultured peritoneal mesothelial cells with lipopolysaccharides (LPS) in order to stimulate the environment of peritonitis and investigate whether lipopolysaccharides could induce epithelial-to-mesenchymal transition (EMT). Oxidative stress could stimulate fibrogenesis while selenium has antioxidant properties. So, this study also explored whether selenium supplementation affects lipopolysaccharide-induced EMT and fibrosis. We found that lipopolysaccharides could activate EMT changes such as the loss of E-cadherin and the increase of α-smooth muscle actin (α-SMA), collagen I, vimentin, and fibronectin (FN), while selenium inhibits EMT by modulating reactive oxygen species (ROS) generation and ROS/MMP-9 signaling pathways in peritoneal mesothelial cells. Moreover, it was revealed that selenium decreased the EMT events of peritoneal mesothelial cells via inhibition of PI3k/AKT pathways. In conclusion, these findings enable a better understanding of the mechanism of peritoneal fibrosis and explore a new idea for the prevention and treatment.

Down-regulation of Ras-related protein Rab 5C-dependent endocytosis and glycolysis in cisplatin-resistant ovarian cancer cell lines

Drug resistance poses a major challenge to ovarian cancer treatment. Understanding mechanisms of drug resistance is important for finding new therapeutic targets. In the present work, a cisplatin-resistant ovarian cancer cell line A2780-DR was established with a resistance index of 6.64. The cellular accumulation of cisplatin was significantly reduced in A2780-DR cells as compared with A2780 cells consistent with the general character of drug resistance. Quantitative proteomic analysis identified 340 differentially expressed proteins between A2780 and A2780-DR cells, which involve in diverse cellular processes, including metabolic process, cellular component biogenesis, cellular processes, and stress responses. Expression levels of Ras-related proteins Rab 5C and Rab 11B in A2780-DR cells were lower than those in A2780 cells as confirmed by real-time quantitative PCR and Western blotting. The short hairpin (sh)RNA-mediated knockdown of Rab 5C in A2780 cells resulted in markedly increased resistance to cisplatin whereas overexpression of Rab 5C in A2780-DR cells increases sensitivity to cisplatin, demonstrating that Rab 5C-dependent endocytosis plays an important role in cisplatin resistance. Our results also showed that expressions of glycolytic enzymes pyruvate kinase, glucose-6-phosphate isomerase, fructose-bisphosphate aldolase, lactate dehydrogenase, and phosphoglycerate kinase 1 were down-regulated in drug resistant cells, indicating drug resistance in ovarian cancer is directly associated with a decrease in glycolysis. Furthermore, it was found that glutathione reductase were up-regulated in A2780-DR, whereas vimentin, HSP90, and Annexin A1 and A2 were down-regulated. Taken together, our results suggest that drug resistance in ovarian cancer cell line A2780 is caused by multifactorial traits, including the down-regulation of Rab 5C-dependent endocytosis of cisplatin, glycolytic enzymes, and vimentin, and up-regulation of antioxidant proteins, suggesting Rab 5C is a potential target for treatment of drug-resistant ovarian cancer. This constitutes a further step toward a comprehensive understanding of drug resistance in ovarian cancer.

FHIT suppresses epithelial-mesenchymal transition (EMT) and metastasis in lung cancer through modulation of microRNAs

Metastasis is the principal cause of cancer death and occurs through multiple, complex processes that involve the concerted action of many genes. A number of studies have indicated that the Fragile Histidine Triad (FHIT) gene product, FHIT, functions as a tumor suppressor in a variety of common human cancers. Although there are suggestions of a role for FHIT loss in progression of various cancers, a role for such loss in metastasis has not been defined. Here, via in vivo and in vitro assays, we reveal that the enforced expression of FHIT significantly suppresses metastasis, accompanied by inhibition of the epithelial-mesenchymal transition (EMT), a process involved in metastasis through coordinate modulation of EMT-related genes. Specifically, miR-30c, a FHIT-upregulated microRNA, contributes to FHIT function in suppression of EMT and metastasis by directly targeting metastasis genes Metadherin (MTDH), High-mobility group AT—hook 2 (HMGA2), and the mesenchymal markers, Vimentin (VIM) and Fibronectin (FN1), in human lung cancer. Finally, we demonstrate that the expression pattern of FHIT and miR-30c is inversely correlated with that of MTDH and HMGA2 in normal tissue, non-metastatic and metastatic tumors, serving as a potential biomarker for metastasis in lung cancer.

Although Fragile Histidine Triad (FHIT) is known as a potential tumor suppressor gene in terms of tumor initiation and progression, the role of FHIT in the metastatic process is not well characterized. Here it is shown that FHIT reduces the motility and invasiveness of lung cancer cells in vitro and ability to metastasize in vivo, at least partially through the miR-30c-mediated suppression of EMT, a critical process during tumor metastasis. This study provides new insights into the role of FHIT and a FHIT-activated miRNA, miR-30c, as crucial modulators in lung metastasis.

Triclosan potentiates epithelial-to-mesenchymal transition in anoikis-resistant human lung cancer cells

Alteration of cancer cell toward mesenchymal phenotype has been shown to potentiate tumor aggressiveness by increasing cancer cell metastasis. Herein, we report the effect of triclosan, a widely used antibacterial agent found in many daily products, in enhancing the epithelial-to-mesenchymal transition (EMT) in aggressive anoikis resistant human H460 lung cancer cells. EMT has been long known to increase abilities of the cells to increase migration, invasion, and survival in circulating system. The present study reveals that treatment of the cancer cells with triclosan at the physiologically related concentrations significantly increased the colony number of the cancer cells assessed by tumor formation assay. Also, the mesenchymal-like morphology and decrease in cell-to-cell adhesion were observed in triclosan-treated cells. Importantly, western blot analysis revealed that triclosan-treated cells exhibited decreased E-cadherin, while the levels of EMT markers, namely N-cadherin, vimentin, snail and slug were found to be significantly up-regulated. Furthermore, EMT induced by triclosan treatment was accompanied by the activation of focal adhesion kinase/ATP dependent tyrosine kinase (FAK/Akt) and Ras-related C3 botulinum toxin substrate 1 (Rac1), which enhanced the ability of the cells to migrate and invade. In conclusion, we demonstrated for the first time that triclosan may potentiate cancer cells survival in detached condition and motility via the process of EMT. As mentioned capabilities are required for success in metastasis, the present study provides the novel toxicological information and encourages the awareness of triclosan use in cancer patients.

Foramen ovale closure is a process of endothelial-to-mesenchymal transition leading to fibrosis

Patent foramen ovale (PFO) is an atrial septal deformity present in around 25% of the general population. PFO is associated with major causes of morbidity, including stroke and migraine. PFO appears to be heritable but genes involved in the closure of foramen ovale have not been identified. The aim of this study is to determine molecular pathways and genes that are responsible to the postnatal closure of the foramen ovale. Using Sprague-Dawley rat hearts as a model we analysed the dynamic histological changes and gene expressions at the foramen ovale region between embryonic day 20 and postnatal day 7. We observed a gradual loss of the endothelial marker PECAM1, an upregulation of the mesenchymal marker vimentin and α-smooth muscle actin, the elevation of the transcription factor Snail, and an increase of fibroblast activation protein (FAP) in the foramen ovale region as well as the deposition of collagen-rich connective tissues at the closed foramen ovale, suggesting endothelial-to-mesenchymal transition (EndMT) occurring during foramen ovale closure which leads to fibrosis. In addition, Notch1 and Notch3 receptors, Notch ligand Jagged1 and Notch effector HRT1 were highly expressed in the endocardium of the foramen ovale region during EndMT. Activation of Notch3 alone in an endothelial cell culture model was able to drive EndMT and transform endothelial cells to mesenchymal phenotype. Our data demonstrate for the first time that FO closure is a process of EndMT-mediated fibrosis, and Notch signalling is an important player participating in this process. Elucidation of the molecular mechanisms of the closure of foramen ovale informs the pathogenesis of PFO and may provide potential options for screening and prevention of PFO related conditions.

[Transplantation of adipose tissue multipotent stromal cells in the treatment of chronic ischemia of the lower extremities]

The expediency of the stromal cells application, obtained from adipose tissue, was determined in a frame of preclinical investigations conduction, concerning experimental works on laboratory rats, in whom the extremity ischemia was simulated. Histologic and immunohistochemical changes were studied in muscular tissue after transplantation of multipotent stromal cells of own adipose tissue in patients, suffering ischemia of the lower extremity. Reduction of severity of the myofibrills ischemic damage, rapid activation of the muscles regenerative power, accurate stimulation of the angiogenesis processes in 3 mo after transplantation of the cells were demonstrated.

ABCG2/BCRP gene expression is related to epithelial-mesenchymal transition inducer genes in a papillary thyroid carcinoma cell line (TPC-1)

Tumor malignancy is associated with the epithelial-mesenchymal transition (EMT) process and resistance to chemotherapy. However, little is known about the relationship between the EMT and the multidrug-resistance gene in thyroid tumor progression. We investigated whether the expression of the ABCG2/BCRP gene is associated with ZEB1 and other EMT inducer genes involved in tumor dedifferentiation. We established a subpopulation of cells that express the ABCG2/BCRP gene derived from the thyroid papillary carcinoma cell line (TPC-1), the so-called TPC-1 MITO-resistant subline. The most relevant findings in these TPC-1 selected cells were a statistically significant upregulation of ZEB1 and TWIST1 (35- and 15-fold change respectively), no changes in the relative expression of vimentin and SNAIL1, and no expression of E-cadherin. The TPC-1 MITO-resistant subline displayed a faster migration and greater invasive ability than parental cells in correlation with a significant upregulation of the survivin (BIRC5) gene (twofold change, P<0.05). The knockdown of ZEB1 promoted nuclear re-expression of E-cadherin, reduced expression of vimentin, N-cadherin, and BIRC5 genes, and reduced cell migration (P<0.05). Analysis of human thyroid carcinoma showed a slight overexpression of the ABCG2/BCRP at stages I and II (P<0.01), and a higher overexpression at stages III and IV (P<0.01). SNAIL1, TWIST1, and ZEB1 genes showed higher expression at stages III and IV than at stages I and II. E- and N-cadherin genes were upregulated at stages I and II of the disease (ninefold and tenfold change, respectively, P<0.01) but downregulated at stages III and IV (fourfold lower, P<0.01). These results could be a promising starting point for further study of the role of the ABCG2/BCRP gene in the progression of thyroid tumor.

[Prognostic value of ki-67 and vimentin markers in patients with metastatic kidney cancer]

The study was aimed to determine the role of ki- 67 and vimentin markers in choosing the tactics of surgical treatment of patients with metastatic kidney cancer. The analysis of the results of treatment of 71 patients with metastatic renal cell carcinoma was performed. The first group included 16 (22.5%) patients, who underwent complete removal of distant metastases after nephrectomy. The second group consisted of 55 (77.5 %) patients who underwent cytoreductive nephrectomy only. Immunohistochemical analyses of tissues removed were performed in all patients for the evaluation of ki-67 and vimentin expression levels. When comparing the outcomes of patients after complete removal of metastases depending on the vimentin and ki-67 expression levels (< 10% and > 10%), a significant increase in the cumulative survival in the case of absence of vimentin and ki-67 expression of <10 % (log - rank test, P = 0.0001) was revealed. The same pattern was noted in the group of patients who underwent nephrectomy only. In the absence of expression of vimentin and ki-67 < 10%, survival rate in patients who underwent metastasectomy after nephrectomy was significantly higher compared with patients who underwent nephrectomy only (P = 0.001). In the case of positive expression of vimentin and ki-67 > 10%, differences in survival rate in these groups were not observed (P > 0.082). Thus, an association between the vimentin and ki-67 expression levels and the degree of spread of metastatic renal cell carcinoma was identified: the high level of expression of these markers precludes the increase of life expectancy of patients after removal of all metastases.

Excess PLAC8 promotes an unconventional ERK2-dependent EMT in colon cancer

The epithelial-to-mesenchymal transition (EMT) transcriptional program is characterized by repression of E-cadherin (CDH1) and induction of N-cadherin (CDH2), and mesenchymal genes like vimentin (VIM). Placenta-specific 8 (PLAC8) has been implicated in colon cancer; however, how PLAC8 contributes to disease is unknown, and endogenous PLAC8 protein has not been studied. We analyzed zebrafish and human tissues and found that endogenous PLAC8 localizes to the apical domain of differentiated intestinal epithelium. Colon cancer cells with elevated PLAC8 levels exhibited EMT features, including increased expression of VIM and zinc finger E-box binding homeobox 1 (ZEB1), aberrant cell motility, and increased invasiveness. In contrast to classical EMT, PLAC8 overexpression reduced cell surface CDH1 and upregulated P-cadherin (CDH3) without affecting CDH2 expression. PLAC8-induced EMT was linked to increased phosphorylated ERK2 (p-ERK2), and ERK2 knockdown restored cell surface CDH1 and suppressed CDH3, VIM, and ZEB1 upregulation. In vitro, PLAC8 directly bound and inactivated the ERK2 phosphatase DUSP6, thereby increasing p-ERK2. In a murine xenograft model, knockdown of endogenous PLAC8 in colon cancer cells resulted in smaller tumors, reduced local invasion, and decreased p-ERK2. Using MultiOmyx, a multiplex immunofluorescence-based methodology, we observed coexpression of cytosolic PLAC8, CDH3, and VIM at the leading edge of a human colorectal tumor, supporting a role for PLAC8 in cancer invasion in vivo.

Retrospective study and immunohistochemical analysis of canine mammary sarcomas

BACKGROUND

Canine mammary sarcomas (CMSs) are rarely diagnosed in female dogs, which explains the scarcity of immunohistochemical findings concerning those tumors. This paper presents the results of a retrospective study into CMSs and discusses the clinical features of the analyzed tumors, the expression of intermediate filaments CK, Vim, Des and α-SMA, and the expression of p63, Ki67, ERα, PR and p53 protein.

RESULTS

Four percent of all canine mammary tumors (CMTs) were classified as CMSs, and they represented 5.1% of malignant CMTs. The mean age at diagnosis was 11.1 ± 2.8 years. Large breed dogs were more frequently affected (38.7%). The majority of observed CMSs were fibrosarcomas (2.1%). All CMSs expressed vimentin, and higher levels of vimentin expression were noted in fibrosarcomas and osteosarcomas. Ki67 expression was significantly correlated with the grade of CMS.

CONCLUSIONS

Our results revealed that CMSs form a heterogeneous group, therefore, immunohistochemical examinations could support differential and final diagnosis. Although this study analyzed a limited number of samples, the reported results can expand our knowledge about CMSs. Further work is required in this field.

Podoplanin is expressed at the invasive front of esophageal squamous cell carcinomas and is involved in collective cell invasion

The expression of podoplanin is reportedly involved in collective cell invasion, which is independent from the epithelial-mesenchymal transition (EMT). We focused on the expression of podoplanin in esophageal squamous cell carcinomas (ESCC) and investigated the correlation of podoplanin and EMT-related markers, and evaluated its prognostic significance. Five ESCC cell lines were subjected to western blot analysis for podoplanin and EMT markers. The effects of podoplanin on EMT and carcinoma invasion were evaluated with wound healing assays, invasion assays and 3-D culture. Transfection of ectopic podoplanin into a podoplanin-negative ESCC cell line (TE-15) induced cell migration and invasive activity (P < 0.001 and P < 0.05, respectively) without downregulation of E-cadherin. In contrast, transfection of si-podoplanin RNA into a podoplanin-positive ESCC cell line (TE-13) reduced cell migration and invasive activity (P < 0.05). We reviewed 101 patients who had undergone esophagectomy for ESCC. Podoplanin expression was observed in 58 patients (57.4%), and positive expression was positively correlated with expression of E-cadherin (P < 0.01), deeper wall invasion (P < 0.01), venous invasion (P < 0.05) and poorer prognosis (P < 0.01). Multivariate Cox analysis revealed that expression of podoplanin was a significant and independent unfavorable predictor of survival (P < 0.05). These data suggest that podoplanin is significantly associated with and likely contributes to ESCC invasion in the absence of EMT.

B7-H4 enhances oncogenicity and inhibits apoptosis in pancreatic cancer cells

B7-H4 is expressed in a variety of tumor cells and functions as a negative regulator of T cells. However, clarification is needed as to whether B7-H4 mediates tumorigenesis through mechanisms, such as apoptosis, in addition to mediating tumor immune escape. We investigate the mechanisms involved in enhanced oncogenicity and the inhibition of apoptosis by B7-H4 in pancreatic cancer cells. Short interfering RNAs (siRNAs) specific for B7-H4 were evaluated for their ability to knockdown B7-H4 mRNA and protein expression in pancreatic cancer cells and the most effective siRNA was selected for investigating the effect of B7-H4 gene silencing in a number of functional assays. The inhibition of B7-H4 increased cell-cell adhesion and decreased the formation of pseudopodia. It also increased the expression of E-cadherin and decreased the expression of vimentin and CD44. B7-H4 siRNA inhibited cell proliferation, colony formation and migration of pancreatic cancer cells. Moreover, increased apoptosis in pancreatic cancer cells following B7-H4 silencing was demonstrated in vitro by using flow cytometry and in a xenograft tumor model and was associated with increased caspase activity and decreased Erk1/2 phosphorylation both in vitro and in vivo. Loss of B7-H4 function thus prevents tumor growth through many processes, including the induction of apoptosis and inhibition of the Erk1/2 signaling pathway indicating that B7-H4 is a cancer promoter and a potentially important therapeutic target. B7-H4 inhibition might offer an exciting opportunity to inhibit the progression of human pancreatic cancers.

Salmonella transforms follicle-associated epithelial cells into M cells to promote intestinal invasion

Salmonella Typhimurium specifically targets antigen-sampling microfold (M) cells to translocate across the gut epithelium. Although M cells represent a small proportion of the specialized follicular-associated epithelium (FAE) overlying mucosa-associated lymphoid tissues, their density increases during Salmonella infection, but the underlying molecular mechanism remains unclear. Using in vitro and in vivo infection models, we demonstrate that the S. Typhimurium type III effector protein SopB induces an epithelial-mesenchymal transition (EMT) of FAE enterocytes into M cells. This cellular transdifferentiation is a result of SopB-dependent activation of Wnt/β-catenin signaling leading to induction of both receptor activator of NF-κB ligand (RANKL) and its receptor RANK. The autocrine activation of RelB-expressing FAE enterocytes by RANKL/RANK induces the EMT-regulating transcription factor Slug that marks epithelial transdifferentiation into M cells. Thus, via the activity of a single secreted effector, S. Typhimurium transforms primed epithelial cells into M cells to promote host colonization and invasion.

Hypothalamic ventricular ependymal thyroid hormone deiodinases are an important element of circannual timing in the Siberian hamster (Phodopus sungorus)

Exposure to short days (SD) induces profound changes in the physiology and behaviour of Siberian hamsters, including gonadal regression and up to 30% loss in body weight. In a continuous SD environment after approximately 20 weeks, Siberian hamsters spontaneously revert to a long day (LD) phenotype, a phenomenon referred to as the photorefractory response. Previously we have identified a number of genes that are regulated by short photoperiod in the neuropil and ventricular ependymal (VE) cells of the hypothalamus, although their importance and contribution to photoperiod induced physiology is unclear. In this refractory model we hypothesised that the return to LD physiology involves reversal of SD expression levels of key hypothalamic genes to their LD values and thereby implicate genes required for LD physiology. Male Siberian hamsters were kept in either LD or SD for up to 39 weeks during which time SD hamster body weight decreased before increasing, after more than 20 weeks, back to LD values. Brain tissue was collected between 14 and 39 weeks for in situ hybridization to determine hypothalamic gene expression. In VE cells lining the third ventricle, expression of nestin, vimentin, Crbp1 and Gpr50 were down-regulated at 18 weeks in SD photoperiod, but expression was not restored to the LD level in photorefractory hamsters. Dio2, Mct8 and Tsh-r expression were altered by SD photoperiod and were fully restored, or even exceeded values found in LD hamsters in the refractory state. In hypothalamic nuclei, expression of Srif and Mc3r mRNAs was altered at 18 weeks in SD, but were similar to LD expression values in photorefractory hamsters. We conclude that in refractory hamsters not all VE cell functions are required to establish LD physiology. However, thyroid hormone signalling from ependymal cells and reversal of neuronal gene expression appear to be essential for the SD refractory response.

Characterizing the effects of VPA, VC and RCCS on rabbit keratocytes onto decellularized bovine cornea

To investigate the morphological and growth characteristics of rabbit keratocytes when cultured on decellularized cornea under simulate microgravity (SMG) rotary cell culture system (RCCS) and static culture or in plastic culture supplemented with small molecules of valproic acid (VPA) and vitamin C (VC). Bovine corneas were firstly decellularized with Triton X-100 and NH(4)OH and through short-term freezing process. Then cell count kit-8 (CCK-8) and flow cytometry were used to test the effects of VPA and VC on the proliferation, cell cycle and apoptosis of rabbit keratocytes. Hematoxylin-eosin (H&E) staining and scanning electron microscopy (SEM) imaging showed that cells were eliminated in the decellularized bovine corneas. The proliferation of cultured keratocytes was promoted by VPA and VC in the cell proliferation assay. VPA and VC moderately decreased the number of apoptotic cells and obviously promoted cell-cycle entrance of keratocytes. Rabbit keratocytes in plastic displayed spindle shape and rare interconnected with or without VPA and VC. Cells revealed dendritic morphology and reticular cellular connections when cultured on the carriers of decellularized corneas supplemented with VPA and VC even in the presence of 10% fetal bovine serum (FBS). When cultured in RCCS supplemented with VPA, VC and 10% FBS, keratocytes displayed round shape with many prominences and were more prone to grow into the pores of carriers with aggregation. Reverse transcription-polymerase chain reaction (RT-PCR) analysis proved that the keratocytes cultured on decellularized bovine cornea under SMG with VPA and VC expressed keratocan and lumican. Keratocytes cultured on plastic expressed lumican but not keratocan. Immunofluorescence identification revealed that cells in all groups were positively immunostained for vimentin. Keratocytes on decellularized bovine cornea under SMG or in static culture were positively immunostained for keratocan and lumican. Thus, we reasonably made a conclusion that the combination of VPA, VC, RCCS and decellularized corneal carriers provide a good condition for keratocytes to well grow. Keratocytes can be manipulated to be aggregates or physiological morphological growth in vitro, which are important for the research of corneal stem cells and corneal tissue engineering.

A new safety concern for glaucoma treatment demonstrated by mass spectrometry imaging of benzalkonium chloride distribution in the eye, an experimental study in rabbits

We investigated in a rabbit model, the eye distribution of topically instilled benzalkonium_(BAK) chloride a commonly used preservative in eye drops using mass spectrometry imaging. Three groups of three New Zealand rabbits each were used: a control one without instillation, one receiving 0.01%BAK twice a day for 5 months and one with 0.2%BAK one drop a day for 1 month. After sacrifice, eyes were embedded and frozen in tragacanth gum. Serial cryosections were alternately deposited on glass slides for histological (hematoxylin-eosin staining) and immunohistological controls (CD45, RLA-DR and vimentin for inflammatory cell infiltration as well as vimentin for Müller glial cell activation) and ITO or stainless steel plates for MSI experiments using Matrix-assisted laser desorption ionization time-of-flight. The MSI results were confirmed by a round-robin study on several adjacent sections conducted in two different laboratories using different sample preparation methods, mass spectrometers and data analysis softwares. BAK was shown to penetrate healthy eyes even after a short duration and was not only detected on the ocular surface structures, but also in deeper tissues, especially in sensitive areas involved in glaucoma pathophysiology, such as the trabecular meshwork and the optic nerve areas, as confirmed by images with histological stainings. CD45-, RLA-DR- and vimentin-positive cells increased in treated eyes. Vimentin was found only in the inner layer of retina in normal eyes and increased in all retinal layers in treated eyes, confirming an activation response to a cell stress. This ocular toxicological study confirms the presence of BAK preservative in ocular surface structures as well as in deeper structures involved in glaucoma disease. The inflammatory cell infiltration and Müller glial cell activation confirmed the deleterious effect of BAK. Although these results were obtained in animals, they highlight the importance of the safety-first principle for the treatment of glaucoma patients.

Transforming growth factor-β transiently induces vimentin expression and invasive capacity in a canine mammary gland tumor cell line

The epithelial-mesenchymal transition (EMT) is a crucial event that occurs during cancer metastasis and can be induced by transforming growth factor-β (TGF-β) in various tumor cells in vitro. However, little is known about the effects of TGF-β in canine mammary gland tumors (CMGTs). Here, we investigated the role of TGF-β in CMGT. We observed that treatment of the CMGT cell line CHMp13a with TGF-β1 leads to transient induction of the mesenchymal marker vimentin. Real-time measurements of cellular electrical impedance also showed that CMGT invasiveness is transiently increased by TGF-β1 treatment, but is reversed after prolonged stimulation. This phenomenon is similar to the mesenchymal-epithelial transition (MET, the reverse phenomenon of EMT), and a process that is implicated in the establishment of secondary metastatic lesions.

Revisiting epithelial-to-mesenchymal transition through adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) has a 5-year survival rate of 90%. The 15-year survival rate drops to 10% due to recurrence and invasion. ACC has three subtypes: cribriform, tubular, and solid. The cribriform subtype has the best prognosis and the solid subtype has the worst prognosis. By immunohistochemistry of tissue sections, we showed that the solid form expresses αvβ6 integrin and tenascin-C, which are known promoters of epithelial-to-mesenchymal transition (EMT). We also defined two ACC cell lines with the characteristics of the cribriform and solid subtype. The SACC83 cells grow in basaloid-like clusters and express high levels of E-cadherin. In contrast, the ACCh cells are more myoepithelial-like and express high levels of vimentin and of αvβ6 integrin. The ACCh cells are highly invasive and this behavior is dependent upon the αvβ6 integrin function. Our results suggest that the transition from the cribriform to solid form may occur through EMT.

Functional inactivation of thyroid transcription factor-1 in PCCl3 thyroid cells

Thyroid transcription factor-1 (TTF-1) is a key regulator of thyroid development and function. In order to identify the genes whose expression depends on TTF-1 transcriptional activity within the thyrocyte we analyzed the consequence of the functional inactivation of this factor in PCCl3 cells. The expression of a fusion protein composed of the DNA binding domain of TTF-1 and of the strong repressive domain of the engrailed protein resulted in a dramatic loss of epithelial cell morphology and in proliferation arrest. These changes were reversed when the inhibition of endogenous TTF-1 was relieved. No change was observed when a similar fusion protein containing point mutations abolishing DNA binding activity was produced in the cells. Besides the expected down-regulation of expression of the main genes linked to the differentiated thyroid function, we observed a decreased expression of the transcription factors Hhex, Pax 8 and TTF-2 and of E-cadherin. By contrast, both ThOX-1 and DUOXA-1 genes were up-regulated, as well as the ones encoding vimentin and several proteins involved in cell cycle arrest. Our data thus extend the known roles of TTF-1 in thyroid development and in the expression of differentiated function in the adult organ to the control of epithelial morphology and of cell division in mature thyrocytes.

Acquired resistance to peloruside A and laulimalide is associated with downregulation of vimentin in human ovarian carcinoma cells

PURPOSE

Acquired β-tubulin alterations in human ovarian carcinoma 1A9 cells were previously shown to confer resistance to the microtubule stabilizing agents peloruside A (PLA) and laulimalide (LAU). We examined the proteome of resistant cells to see what other protein changes occurred as a result of the acquired drug resistance.

METHODS

Two-dimensional differential in-gel electrophoresis was performed to explore differentially expressed proteins in the resistant 1A9-R1 (R1) and 1A9-L4 (L4) cells. The proteins on the gels were identified by MALDI-TOF MS, and altered protein abundance was confirmed by Western blotting and immunocytochemistry. Vimentin expression was restored in vimentin-deficient L4 cells by transfecting a full-length human vimentin cDNA, and sensitivity to PLA and LAU were tested using an MTT cell proliferation assay.

RESULTS

Proteomic analysis identified several proteins that were significantly altered in the resistant cells relative to the parental 1A9 cells. Using Western blotting and immunocytochemistry, a decreased vimentin abundance in the L4 cells was validated. Vimentin levels were unchanged in PLA-resistant R1 cells and paclitaxel/epothilone-resistant derivatives of 1A9 cells. Vimentin cDNA transfection into L4 cells partially restored PLA and LAU sensitivity.

CONCLUSIONS

Downregulation of vimentin contributes to the resistance of 1A9 cells to the microtubule stabilizing agents, PLA and LAU.