Transgelin promotes migration and invasion of cancer stem cells

Prognostic Value of Tumor Size in Colon Cancer-Smaller is Better?

BACKGROUND

The prognostic value of tumor size in colon cancer remains controversial. This study aimed to reveal the correlation between tumor size and prognosis of colon cancer.

METHODS

A total of 491 patients with colon cancer were included in this study. The correlation of tumor size with prognosis, mismatch repair status, and other clinicopathological characteristics as well as tumor microenvironment was analyzed.

RESULTS

For stage IIA microsatellite stable (MSS) colon cancer, tumors sized <3.5 cm and ≥5 cm were associated with a poorer disease free survival (DFS) compared with tumors sized between 3.5 and 5 cm (P = .002). Small tumor size (HR = 5.098, P = .001) and large tumor size (HR = 2.749, P = .029) were found to be independent prognostic factors for stage IIA MSS colon cancer. Moreover, high expression of transgelin (TAGLN), a marker of cancer-associated fibroblasts (CAFs), was found to be an independent prognostic factor for poorer DFS (HR = 9.651, P = .009), which was also associated with smaller tumor size (P = .027).

CONCLUSION

Small (<3.5 cm) and large (≥5 cm) tumor sizes are associated with decreased DFS in stage IIA MSS colon cancer. Enrichment of TAGLN+ CAFs is associated with decreased DFS and small tumor size.

Stromal heterogeneity may explain increased incidence of metaplastic breast cancer in women of African descent

The biologic basis of genetic ancestry-dependent variability in disease incidence and outcome is just beginning to be explored. We recently reported enrichment of a population of ZEB1-expressing cells located adjacent to ductal epithelial cells in normal breasts of women of African ancestry compared to those of European ancestry. In this study, we demonstrate that these cells have properties of fibroadipogenic/mesenchymal stromal cells that express PROCR and PDGFRα and transdifferentiate into adipogenic and osteogenic lineages. PROCR + /ZEB1 + /PDGFRα+ (PZP) cells are enriched in normal breast tissues of women of African compared to European ancestry. PZP: epithelial cell communication results in luminal epithelial cells acquiring basal cell characteristics and IL-6-dependent increase in STAT3 phosphorylation. Furthermore, level of phospho-STAT3 is higher in normal and cancerous breast tissues of women of African ancestry. PZP cells transformed with HRasG12V ± SV40-T/t antigens generate metaplastic carcinoma suggesting that these cells are one of the cells-of-origin of metaplastic breast cancers.

LPA receptor 1 (LPAR1) is a novel interaction partner of Filamin A that promotes Filamin A phosphorylation, MRTF-A transcriptional activity and oncogene-induced senescence

Myocardin-related transcription factors A and B (MRTFs) are coactivators of Serum Response Factor (SRF), which controls fundamental biological processes such as cell growth, migration, and differentiation. MRTF and SRF transcriptional activity play an important role in hepatocellular carcinoma (HCC) growth, which represents the second leading cause of cancer-related mortality in humans worldwide. We, therefore, searched for druggable targets in HCC that regulate MRTF/SRF transcriptional activity and can be exploited therapeutically for HCC therapy. We identified the G protein-coupled lysophosphatidic acid receptor 1 (LPAR1) as a novel interaction partner of MRTF-A and Filamin A (FLNA) using fluorescence resonance energy transfer-(FRET) and proximity ligation assay (PLA) in vitro in HCC cells and in vivo in organoids. We found that LPAR1 promotes FLNA phosphorylation at S2152 which enhances the complex formation of FLNA and MRTF-A, actin polymerization, and MRTF transcriptional activity. Pharmacological blockade or depletion of LPAR1 prevents FLNA phosphorylation and complex formation with MRTF-A, resulting in reduced MRTF/SRF target gene expression and oncogene-induced senescence. Thus, inhibition of the LPAR1-FLNA-MRTF-A interaction represents a promising strategy for HCC therapy.

RNA-sequencing of human aortic valves identifies that miR-629-3p and TAGLN miRNA-mRNA pair involving in calcified aortic valve disease

This study aimed to uncover the microRNA and messenger RNA (miRNA/mRNA) interactions in the pathophysiological process of calcified aortic valve disease (CAVD) of the human aortic valve. RNA sequencing of six selected samples (3 healthy control samples vs. 3 CAVD samples) was performed to obtain mRNA and miRNA sequences, and differential expression (DE) analysis of miRNA and mRNAs was performed. To build a CAVD-specific miRNA-mRNA interactome, the upregulated mRNAs and downregulated miRNAs were selected, followed by the establishment of inverse DE of mRNA-miRNA co-expression network based on Pearson's correlation coefficient using miRanda in the R language software. Subsequently, pathway enrichment analysis was performed to elucidate CAVD-related pathways that were likely mediated by miRNA regulatory mechanisms. In addition, miRNAs with an mRNA correlation greater than 0.9 in the co-expression network were selected for anti-calcification verification in a CAVD cellular model. We identified 216 mRNAs (99 downregulated and 117 upregulated) and 602 miRNAs (371 downregulated and 231 upregulated) that were differentially expressed between CAVD and healthy aortic valves. After applying Pearson's correlation toward miRNA-mRNA targets, a regulatory network of 67 miRNAs targeting 76 mRNAs was created. The subsequent pathway enrichment analysis of these targeted mRNAs elucidated that genes within the focal adhesion pathway are likely mediated by miRNA regulatory mechanisms. The selected hsa-miR-629-3p and TAGLN pair exhibited anti-calcification effects on osteogenic differentiation-induced human aortic valve interstitial cells (hVICs). On integrating the miRNA and mRNA sequencing data for healthy aortic valves and those with CAVD, the CAVD-associated miRNA-mRNA interactome and related pathways were elucidated. Additional cell function data demonstrated anti-calcification effects of the selected hsa-miR-629-3p targeting TAGLN, validating that it is a potential therapeutic target for inhibiting CAVD.

The Warburg effect is necessary to promote glycosylation in the blastema during zebrafish tail regeneration

Throughout their lifetime, fish maintain a high capacity for regenerating complex tissues after injury. We utilized a larval tail regeneration assay in the zebrafish Danio rerio, which serves as an ideal model of appendage regeneration due to its easy manipulation, relatively simple mixture of cell types, and superior imaging properties. Regeneration of the embryonic zebrafish tail requires development of a blastema, a mass of dedifferentiated cells capable of replacing lost tissue, a crucial step in all known examples of appendage regeneration. Using this model, we show that tail amputation triggers an obligate metabolic shift to promote glucose metabolism during early regeneration similar to the Warburg effect observed in tumor forming cells. Inhibition of glucose metabolism did not affect the overall health of the embryo but completely blocked the tail from regenerating after amputation due to the failure to form a functional blastema. We performed a time series of single-cell RNA sequencing on regenerating tails with and without inhibition of glucose metabolism. We demonstrated that metabolic reprogramming is required for sustained TGF-β signaling and blocking glucose metabolism largely mimicked inhibition of TGF-β receptors, both resulting in an aberrant blastema. Finally, we showed using genetic ablation of three possible metabolic pathways for glucose, that metabolic reprogramming is required to provide glucose specifically to the hexosamine biosynthetic pathway while neither glycolysis nor the pentose phosphate pathway were necessary for regeneration.

Interpretable, Scalable, and Transferrable Functional Projection of Large-Scale Transcriptome Data Using Constrained Matrix Decomposition

Large-scale transcriptome data, such as single-cell RNA-sequencing data, have provided unprecedented resources for studying biological processes at the systems level. Numerous dimensionality reduction methods have been developed to visualize and analyze these transcriptome data. In addition, several existing methods allow inference of functional variations among samples using gene sets with known biological functions. However, it remains challenging to analyze transcriptomes with reduced dimensions that are interpretable in terms of dimensions’ directionalities, transferrable to new data, and directly expose the contribution or association of individual genes. In this study, we used gene set non-negative principal component analysis (gsPCA) and non-negative matrix factorization (gsNMF) to analyze large-scale transcriptome datasets. We found that these methods provide low-dimensional information about the progression of biological processes in a quantitative manner, and their performances are comparable to existing functional variation analysis methods in terms of distinguishing multiple cell states and samples from multiple conditions. Remarkably, upon training with a subset of data, these methods allow predictions of locations in the functional space using data from experimental conditions that are not exposed to the models. Specifically, our models predicted the extent of progression and reversion for cells in the epithelial-mesenchymal transition (EMT) continuum. These methods revealed conserved EMT program among multiple types of single cells and tumor samples. Finally, we demonstrate this approach is broadly applicable to data and gene sets beyond EMT and provide several recommendations on the choice between the two linear methods and the optimal algorithmic parameters. Our methods show that simple constrained matrix decomposition can produce to low-dimensional information in functionally interpretable and transferrable space, and can be widely useful for analyzing large-scale transcriptome data.

Differential Expression of Drosophila Transgelins Throughout Development

Transgelins are a conserved family of actin-binding proteins involved in cytoskeletal remodeling, cell contractility, and cell shape. In both mammals and Drosophila, three genes encode transgelin proteins. Transgelins exhibit a broad and overlapping expression pattern, which has obscured the precise identification of their role in development. Here, we report the first systematic developmental analysis of all Drosophila transgelin proteins, namely, Mp20, CG5023, and Chd64 in the living organism. Drosophila transgelins display overall higher sequence identity with mammalian TAGLN-3 and TAGLN-2 than with TAGLN. Detailed examination in different developmental stages revealed that Mp20 and CG5023 are predominantly expressed in mesodermal tissues with the onset of myogenesis and accumulate in the cytoplasm of all somatic muscles and heart in the late embryo. Notably, at postembryonic developmental stages, Mp20 and CG5023 are detected in the gut's circumferential muscles with distinct subcellular localization: Z-lines for Mp20 and sarcomere and nucleus for CG5023. Only CG5023 is strongly detected in the adult fly in the abdominal, leg, and synchronous thoracic muscles. Chd64 protein is primarily expressed in endodermal and ectodermal tissues and has a dual subcellular localization in the cytoplasm and the nucleus. During the larval-pupae transition, Chd64 is expressed in the brain, eye, legs, halteres, and wings. In contrast, in the adult fly, Chd64 is expressed in epithelia, including the alimentary tract and genitalia. Based on the non-overlapping tissue expression, we predict that Mp20 and CG5023 mostly cooperate to modulate muscle function, whereas Chd64 has distinct roles in epithelial, neuronal, and endodermal tissues.

RETRACTED: Tumor cell-secreted exosomal miR-22-3p inhibits transgelin and induces vascular abnormalization to promote tumor budding

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the editor-in-chief. The editor-in-chief was informed of evidence for image duplication in identical or altered fashion in Figures 3A and 8D, as well as undisclosed reuse of an image in Figure 5B from a previous article in Cell Death & Disease (https://doi.org/10.1038/s41419-018-0902-5), in a PubPeer thread: https://pubpeer.com/publications/F5B591481C516F4CE42C7925AC48E9. Image analysis performed by the journal's editorial office confirmed these findings. This reuse (and in part misrepresentation) of data without appropriate attribution represents a severe abuse of the scientific publishing system.

TAGLN Is Downregulated by TRAF6-Mediated Proteasomal Degradation in Prostate Cancer Cells

Transgelin (TAGLN, also named SM22) is an actin-associated protein and affects dynamics of actin filaments. Deregulation of TAGLN contributes to the development of different cancers, and it is commonly considered to be a tumor suppressor. TAGLN is usually downregulated in prostate cancer; however, the detailed functions of TAGLN in prostate cancer and how TAGLN is regulated remains unclear. In this study, we confirmed that TAGLN is downregulated in prostate cancer tissues and demonstrated that the downregulation of TAGLN occurs through proteasomal degradation. Next, we found that the expression level of TAGLN is inversely correlated with TRAF6. We screened more than 20 E2-E3 pairs by in vitro ubiquitination assay and found that the E2A-TRAF6 pair catalyzed mono ubiquitination of TAGLN. We then identified the ubiquitination sites of TAGLN to be on K89 or K108 residues and demonstrated that ubiquitination of TAGLN on K89/K108 are important for TRAF6-mediated proteasomal degradation. Furthermore, we investigated the function of TAGLN in prostate cancer cells. We found that ablation of TAGLN promoted prostate cancer cell proliferation and suppressed their migration via activation of NF-κB and Myc signaling pathways. Overall, our study provided new insights into the mechanisms underlying TAGLN expression and activity in prostate cancer. IMPLICATIONS: E3 ligase TRAF6 mediate mono-ubiquitination and degradation of TAGLN, which leads to activation of NF-κB and Myc signaling pathways in prostate cancer cells.

Transgelins: Cytoskeletal Associated Proteins Implicated in the Metastasis of Colorectal Cancer

Transgelins, including transgelin-1 (T-1), transgelin-2 (T-2), and transgelin-3 (T-3), are a family of actin-binding proteins (ABPs) that can alter the structure and morphology of the cytoskeleton. These proteins function by regulating migration, proliferation and apoptosis in many different cancers. Several studies have shown that in various types of tumor cells, including colorectal cancer (CRC) cells, and in the tumor microenvironment, the expression and biological effects of transgelins are diverse and may transform during tumor progression. Previous researches have demonstrated that transgelin levels are positively correlated with metastasis in CRC, and down-regulating their expression can inhibit this process. In advanced disease, T-1 is a tumor activator with increasing expression, and T-2 expression increases with the progression of CRC. Finally, T-3 is only expressed in neurons and is not associated with CRC. This evidence suggests that T-1 and T-2 are potential biomarkers and therapeutic targets for CRC metastasis.

Deglycosylated Azithromycin Targets Transgelin to Enhance Intestinal Smooth Muscle Function

Azithromycin (AZM) has been widely used as an antibacterial drug for many years. It has also been used to treat delayed gastric emptying. However, it exerts several side effects. We found that deglycosylated AZM (Deg-AZM or CP0119), an AZM metabolite, is a positively strong intestinal agonist that may result in the intestinal mobility experienced by patients after AZM administration. We confirmed that Deg-AZM can function strongly on intestinal peristalsis and identified transgelin as its potential molecular target. Furthermore, our pharmacological studies showed that the binding of Deg-AZM to transgelin enhanced the contractility of intestinal smooth muscle cells by facilitating the assembly of actin filaments into tight bundles and stress fibers. Specifically, Deg-AZM promoted intestinal peristaltic activity in wild-type mice but not in transgelin (-/-) mice. Moreover, Deg-AZM did not exert antibacterial activity and did not disrupt intestinal flora. Thus, Deg-AZM may become a potential drug for slow-transit constipation treatment.

Transgelin interacts with PARP1 in human colon cancer cells

Background

Transgelin, an actin-binding protein, is associated with cytoskeleton remodeling. Findings from our previous studies demonstrated that transgelin was up-regulated in node-positive colorectal cancer (CRC) versus node-negative disease. Over-expression of TAGLN affected the expression of 256 downstream transcripts and increased the metastatic potential of colon cancer cells in vitro and in vivo. This study aims to explore the mechanisms through which transgelin participates in the metastasis of colon cancer cells.

Methods

Immunofluorescence and immunoblotting analysis were used to determine the cellular localization of endogenous and exogenous transgelin in colon cancer cells. Co-immunoprecipitation and subsequently high-performance liquid chromatography/tandem mass spectrometry were performed to identify the proteins that were potentially interacting with transgelin. The 256 downstream transcripts regulated by transgelin were analyzed with bioinformatics methods to discriminate the specific key genes and signaling pathways. The Gene-Cloud of Biotechnology Information (GCBI) tools were used to predict the potential transcription factors (TFs) for the key genes. The predicted TFs corresponded to the proteins identified to interact with transgelin. The interaction between transgelin and the TFs was verified by co-immunoprecipitation and immunofluorescence.

Results

Transgelin was found to localize in both the cytoplasm and nucleus of the colon cancer cells. Approximately 297 proteins were identified to interact with transgelin. The overexpression of TAGLN led to the differential expression of 184 downstream genes. Network topology analysis discriminated seven key genes, including CALM1, MYO1F, NCKIPSD, PLK4, RAC1, WAS and WIPF1, which are mostly involved in the Rho signaling pathway. Poly (ADP-ribose) polymerase-1 (PARP1) was predicted as the unique TF for the key genes and concurrently corresponded to the DNA-binding proteins potentially interacting with transgelin. The interaction between PARP1 and transgelin in human RKO colon cancer cells was further validated by immunoprecipitation and immunofluorescence assays.

Conclusions

Our results suggest that transgelin binds to PARP1 and regulates the expression of downstream key genes, which are mainly involved in the Rho signaling pathway, and thus participates in the metastasis of colon cancer.

Cartilage Oligomeric Matrix Protein promotes epithelial-mesenchymal transition by interacting with Transgelin in Colorectal Cancer

Background and Purpose: The role of the cartilage oligomeric matrix protein (COMP) in epithelial-mesenchymal transition (EMT) in tumor progression has been studied, but its exact regulatory mechanism remains unknown.

Methods: The interaction between COMP and the actin-binding protein transgelin (TAGLN) was identified by interaction protein prediction and co-immunoprecipitation and verified through the stochastic optical reconstruction microscopy (STORM) and duolink experiments. Western blot and immunofluorescence analyses were conducted to detect the changes in EMT-related markers after COMP overexpression and knockdown. Molecular docking and Biacore of the interaction interface of COMP/TAGLN revealed that Chrysin directly targeted COMP. The promotion of COMP and the Chrysin inhibition of EMT were detected through the cell migration, invasion, apoptosis, and xenotransplantation of nude mice.

Results: COMP interacts with TAGLN in EMT in colorectal cancer to regulate cytoskeletal remodeling and promote malignant progression. COMP is highly expressed in highly malignant colorectal cancer and positively correlated with TAGLN expression. COMP knockdown can inhibit colorectal cancer metastasis and invasion, whereas COMP overexpression promotes EMT in colorectal cancer. Through virtual screening of the protein interaction interface, Chrysin, a flavonoid compound extracted from Oroxylum indicum, was found to have the highest docking score to the COMP/TAGLN complex. Chrysin inhibited COMP, thereby preventing EMT and the malignant progression of colorectal cancer.

Conclusions: This study illustrated the role of COMP in EMT and suggested that COMP/TAGLN may be a potential tumor therapeutic target. Chrysin exhibits obvious antitumor effects. This work provides a preliminary antitumor therapy to target COMP or its interaction protein to inhibit EMT.

Transgelin is a poor prognostic factor associated with advanced colorectal cancer (CRC) stage promoting tumor growth and migration in a TGFβ-dependent manner

Colorectal cancer (CRC) is the fourth most common cancer type globally. Investigating the signaling pathways that maintain cancer cell phenotype can identify new biomarkers for targeted therapy. Aberrant transforming growth factor-β (TGFβ) signaling has been implicated in CRC progression, however, the exact mechanism by which TGFβ exerts its function is still being unraveled. Herein, we investigated TAGLN expression, prognostic value, and its regulation by TGFβ in CRC. While TAGLN was generally found to be downregulated in CRC, elevated expression of TAGLN was associated with advanced CRC stage and predicted poor overall survival (hazard ratio (HR) = 1.8, log-rank test P-value = 0.014) and disease-free survival (HR = 1.6, log-rank test P-value = 0.046), hence implicating TAGLN as poor prognostic factor in CRC. Forced expression of TAGLN was associated with enhanced CRC cell proliferation, clonogenic growth, cell migration and in vivo tumor formation in immunocompromised mice, while targeted depletion of TAGLN exhibited opposing biological effects. Global gene expression profiling of TAGLN-overexpressing or TAGLN-deficient CRC cell lines revealed deregulation of multiple cancer-related genes and signaling pathways. Transmission electron microscopy (TEM) revealed ultrastructural changes due to loss of TAGLN, including disruption of actin cytoskeleton organization and aberrant actin filament distribution. Hierarchical clustering, principle component, and ingenuity pathway analyses revealed distinct molecular profile associated with TAGLN^high CRC patients with remarkable activation of a number of mechanistic networks, including SMARCA4, TGFβ1, and P38 MAPK. The P38 MAPK was the top predicted upstream regulator network promoting cell movement through regulation of several intermediate molecules, including TGFβ1. Concordantly, functional categories associated with cellular movement and angiogenesis were also enriched in TAGLN^high CRC, supporting a model for the molecular mechanisms linking TGFβ-induced upregulation of TAGLN and CRC tumor progression and suggesting TAGLN as potential prognostic marker associated with advanced CRC pathological stage.

Transgelin Silencing Induces Different Processes in Different Breast Cancer Cell Lines

Transgelin is a protein reported to be a marker of several cancers. However, previous studies have shown both up- and down-regulation of transgelin in tumors when compared with non-tumor tissues and the mechanisms whereby transgelin may affect the development of cancer remain largely unknown. Transgelin is especially abundant in smooth muscle cells and is associated with actin stress fibers. These contractile structures participate in cell motility, adhesion, and the maintenance of cell morphology. Here, the role of transgelin in breast cancer is focused on. Initially, the effects of transgelin on cell migration of the breast cancer cell lines, BT 549 and PMC 42, is studied. Interestingly, transgelin silencing increased the migration of PMC 42 cells, but decreased the migration of BT 549 cells. To clarify these contradictory results, the changes in protein abundances after transgelin silencing in these two cell lines are analyzed using quantitative proteomics. The results confirmed the role of transgelin in the migration of BT 549 cells and suggest the involvement of transgelin in apoptosis and small molecule biochemistry in PMC 42 cells. The context-dependent function of transgelin reflects the different molecular backgrounds of these cell lines, which differ in karyotypes, mutation statuses, and proteome profiles.

Therapeutic effects of hydro-alcoholic extract of Achillea wilhelmsii C. Koch on indomethacin-induced gastric ulcer in rats: a proteomic and metabolomic approach

Background

Gastric ulcer is one of the most prevalent diseases worldwide. In Iranian folk medicine, Achillea wilhelmsii (AW) is used as a treatment for gastric ulcer. Previous reports also mentioned Antiulcerogenic properties for this herbal plant. This study investigated the therapeutic effects of Achillea wilhelmsii C. Koch extract on indomethacin-induced gastric lesion in rats, from both proteomic and metabolomic perspectives.

Methods

The rats were divided into 4 groups. Gastric ulceration was induced by a single dose of indomethacin (45 mg/kg) by oral gavage. An amount of 800 mg/kg of AW extract was administered orally. Serum and tissue samples were collected for further investigations. The metabolomic study was performed by ¹H-NMR CPMG spectrometry. Proteomic analysis was also executed by using two dimensional gel electrophoresis (2DE) followed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI/MS/MS). Real time PCR was used to confirm some of the genes.

Results

The macroscopic and microscopic investigations confirmed the effectiveness of the AW extract. There was a panel of metabolites which showed alteration during gastric lesion development. The levels of some of these metabolite reversed nearly to their control values after the administration of AW extract. There were also changes in the levels of some proteins including Alb, Fabp5, Hspb1, Tagln, Lgals7, Csta and Myl9 which were reversed after AW administration.

Conclusions

Our findings suggested that Achillea wilhelmsii C. Koch extract could be a potential therapy to be used for indomethacin-induced gastric lesion treatment in the future. However, further investigations are needed to confirm the results.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2623-4) contains supplementary material, which is available to authorized users.

Oncogenic transgelin-2 is differentially regulated in isocitrate dehydrogenase wild-type vs. mutant gliomas

The presence of an isocitrate dehydrogenase (IDH1/2) mutation in gliomas is associated with favorable outcomes compared to gliomas without the mutation (IDH1/2 wild-type, WT). The underlying biological mechanisms accounting for improved clinical outcomes in IDH1/2 mutant gliomas remain poorly understood, but may, in part, be due to the glioma CpG island methylator phenotype (G-CIMP) and epigenetic silencing of genes. We performed profiling of IDH1/2 WT versus IDH1/2 mutant Grade II and III gliomas and identified transgelin-2 (TAGLN2), an oncogene and actin-polymerizing protein, to be expressed at significantly higher levels in IDH1/2 WT gliomas compared to IDH1/2 mutant gliomas. This differential expression of TAGLN2 was primarily due to promoter hypermethylation in IDH1/2 mutant gliomas, suggesting involvement of TAGLN2 in the G-CIMP. Our results also suggest that TAGLN2 may be involved in progression due to higher expression in glioblastomas compared to IDH1/2 WT gliomas of lower grades. Furthermore, our results suggest that TAGLN2 functions as an oncogene by contributing to proliferation and invasion when overexpressed in IDH1/2 WT glioma cells. Taken together, this study demonstrates a possible link between increased TAGLN2 expression, invasion and poor patient outcomes in IDH1/2 WT gliomas and identifies TAGLN2 as a potential novel therapeutic target for IDH1/2 WT gliomas.

Discovering proteins for chemoprevention and chemotherapy by curcumin in liver fluke infection-induced bile duct cancer

Modulation or prevention of protein changes during the cholangiocarcinoma (CCA) process induced by Opisthorchis viverrini (Ov) infection may become a key strategy for prevention and treatment of CCA. Monitoring of such changes could lead to discovery of protein targets for CCA treatment. Curcumin exerts anti-inflammatory and anti-CCA activities partly through its protein-modulatory ability. To support the potential use of curcumin and to discover novel target molecules for CCA treatment, we used a quantitative proteomic approach to investigate the effects of curcumin on protein changes in an Ov-induced CCA-harboring hamster model. Isobaric labelling and tandem mass spectrometry were used to compare the protein expression profiles of liver tissues from CCA hamsters with or without curcumin dietary supplementation. Among the dysregulated proteins, five were upregulated in liver tissues of CCA hamsters but markedly downregulated in the CCA hamsters supplemented with curcumin: S100A6, lumican, plastin-2, 14-3-3 zeta/delta and vimentin. Western blot and immunohistochemical analyses also showed similar expression patterns of these proteins in liver tissues of hamsters in the CCA and CCA + curcumin groups. Proteins such as clusterin and S100A10, involved in the NF-κB signaling pathway, an important signaling cascade involved in CCA genesis, were also upregulated in CCA hamsters and were then suppressed by curcumin treatment. Taken together, our results demonstrate the important changes in the proteome during the genesis of O. viverrini-induced CCA and provide an insight into the possible protein targets for prevention and treatment of this cancer.

Transgelin-2 is a novel target of KRAS-ERK signaling involved in the development of pancreatic cancer

Background

The KRAS mutation is the driving force of pancreatic ductal adenocarcinoma (PDAC). Downstream effectors of KRAS signal pathways are crucial to the development of PDAC. The purpose of this study was to investigate the relationship between KRAS mutation and transgelin-2. Transgelin-2 is highly expressed in PDAC tissues compared with adjacent normal tissues. The underlying mechanism for upregulating transgelin-2 is largely unknown.

Methods

Expression of transgelin-2 was analyzed by microarray data and qRT-PCR. The effect of KRAS signaling on transgelin-2 expression was examined in PDAC cells in the presence or absence of the ERK inhibitor. The interaction of transgelin-2 with ERK was confirmed by immunoprecipitation. ERK-mediated Phosphorylation of transglein-2 was detected by in vivo and in vitro kinase assays. The gain-of-function and loss-of-function approaches were used to examine the role of phosphorylation of transgelin-2 on cell proliferation. Phosphorylation of transgelin-2 was detected by immunohistochemistry in PDAC tissues.

Results

Here we found transgelin-2 expression was induced by KRAS mutation. In the case of KRAS mutation, ERK2 interacted with 29–31 amino acids of transgelin-2 and subsequently phosphorylated the S145 residue of transgelin-2. S145 phosphorylation of transgelin-2 played important roles in cell proliferation and tumorigenesis of PDAC. In addition, S145 phosphorylation of transgelin-2 was associated with a poor prognosis in patients with PDAC.

Conclusions

This study indicated that KRAS-ERK-mediated transeglin-2 phosphorylation played an important role in the development of PDAC. Inhibition of transgelin-2 phosphorylation may be a potential therapeutic strategy for targeting PDAC with KRAS mutation.

Quantitative proteomics reveals that distant recurrence-associated protein R-Ras and Transgelin predict post-surgical survival in patients with Stage III colorectal cancer

Surgical resection supplemented with adjuvant chemotherapy is the current preferred treatment for Stage III colorectal cancer (CRC). However, as many as 48% of patients who undergo curative resection eventually suffer from incurable distant recurrence. To investigate the molecular mechanisms involved in Stage III CRC post-surgical distant recurrence, we identified a total of 146 differentially expressed proteins (DEPs) associated with distant recurrence in Stage III CRC using TMT-based quantitative mass spectrometry. Among these DEPs, the altered expressions of R-Ras and Transgelin were then validated in 192 individual specimens using immunohistochemistry (IHC). Furthermore, Kaplan-Meier analysis revealed that the levels of R-Ras and Transgelin were significantly associated with 5-year overall survival (OS) and disease-free survival (DFS), and multivariate Cox-regression analyses revealed that R-Ras and Transgelin were independent prognostic factors for OS and DFS, respectively. In conclusion, this study identified potential biochemical players involved in distant recurrence and indicates that R-Ras and Transgelin are potential post-surgical prognostic biomarkers for Stage III CRC. This proteomics data have been submitted to Proteome Xchange under accession number PXD002903.

Elevated transgelin/TNS1 expression is a potential biomarker in human colorectal cancer

Transgelin is an actin-binding protein that regulates cell motility and other important cellular functions. Previous studies have suggested that transgelin expression is associated with cancer development and progression, but its specific role in colorectal cancer (CRC) remains controversial. We analyzed expression of transgelin and its candidate downstream target, tensin 1 (TNS1), in CRC patients using the ONCOMINE, Protein Atlas, and OncoLnc databases. Transgelin and TNS1 mRNA and protein levels were higher in CRC patients and CRC cell lines than in normal tissues and cells. Survival analyses using the OncoLnc database revealed that elevated TAGLN/TNS1 levels were associated with a poor overall survival in CRC patients. Transgelin suppression using siRNA decreased TNS1 expression in CRC cells, demonstrating that transgelin induces the TNS1 expression. Importantly, suppression of transgelin or TNS1 using siRNA decreased proliferation and invasiveness of CRC cells. These results suggest that transgelin/TNS1 signaling promotes CRC cell proliferation and invasion, and that transgelin/TNS1 expression levels could potentially serve as a prognostic and therapeutic target in CRC patients.

Synthesis, antitumor evaluation and microarray study of some new pyrazolo[3,4-d][1,2,3]triazine derivatives

Design and synthesis of new anticancer scaffolds; pyrazolo[3,4-d][1,2,3]triazine derivatives, is a promising solution to overcome drug resistance problem. A series of (E)-2-cyano-N-(aryl)-3-methylthio-3-(substituted-amino)acrylamides 3a-e was synthesized and transformed to the 3-aminopyrazole derivatives 4a-e which were then transformed to the target pyrazolotriazinones 6a-e. All compounds were evaluated for their anticancer activity against three different cancer cell lines namely Huh-7, Panc-1 and CCRF. Compounds 3a, 3c, 6a and 6c showed excellent anticancer activity against Huh-7 cell line (IC₅₀: 4.93-8.84 μM vs doxorubicin 5.43 μM). Similarly, compounds 6a and 6d showed excellent activities against Panc-1 cells (IC₅₀: 9.91 μM and 4.93 μM vs doxorubicin 6.90 μM). Caspase-Glo 3/7 assay was done and the results revealed that the pro-apoptotic activity of the target compounds could be due to the stimulation of caspases 3/7. Microarray experiment for Huh-7 cells treated with 6c was performed to search for other molecular changes. SLC26A3, UGT1A1, UGT2B15, UGT2B7, DNASE1, MUCDH1 and UGT2B17 were among the up-regulated genes, while, GIP3, TAGL, THBS1, IFI27, FSCN1 and SOCS2 were among the most extensively down-regulated genes. These genes belong to apoptosis, metabolism, cell cycle, tumor growth and suppressor genes. Finally, pyrazolo[3,4-d][1,2,3]triazine derivatives could be potent anticancer drugs in the future.

NanoLC-MS coupling of liquid microjunction microextraction for on-tissue proteomic analysis

Mass spectrometry (MS)-based microproteomics on localized regions of tissue sections was achieved by direct coupling of liquid microjunction microextraction with a nanoscale liquid chromatography-tandem MS, resulting in the identification of >500 protein groups from a region as small as 250μm in diameter representing only a few hundred of cells. The method was applied on the examination of benign and tumor regions initially defined by imaging mass spectrometry (IMS) analysis of a consecutive high grade serous ovarian tumor tissue section. Results identified the higher abundance of eukaryotic translation initiation factors eIF4A, its isoform eIF4A2, and eIF5A and its isoform eIF5A2, and lower abundance of actin-binding proteins OBSCN, TAGLN and CNN3 on tumor regions, concomitant with previous findings. This demonstrates the use of the method for downstream characterization of distinct regions identified by IMS. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

The hepatocyte proteome in organotypic rat liver models and the influence of the local microenvironment

BACKGROUND

Liver models that closely mimic the in vivo microenvironment are useful for understanding liver functions, capabilities, and intercellular communication processes. Three-dimensional (3D) liver models assembled using hepatocytes and liver sinusoidal endothelial cells (LSECs) separated by a polyelectrolyte multilayer (PEM) provide a functional system while also permitting isolation of individual cell types for proteomic analyses.

METHODS

To better understand the mechanisms and processes that underlie liver model function, hepatocytes were maintained as monolayers and 3D PEM-based formats in the presence or absence of primary LSECs. The resulting hepatocyte proteomes, the proteins in the PEM, and extracellular levels of urea, albumin and glucose after three days of culture were compared.

RESULTS

All systems were ketogenic and found to release glucose. The presence of the PEM led to increases in proteins associated with both mitochondrial and peroxisomal-based β-oxidation. The PEMs also limited production of structural and migratory proteins associated with dedifferentiation. The presence of LSECs increased levels of Phase I and Phase II biotransformation enzymes as well as several proteins associated with the endoplasmic reticulum and extracellular matrix remodeling. The proteomic analysis of the PEMs indicated that there was no significant change after three days of culture. These results are discussed in relation to liver model function.

CONCLUSIONS

Heterotypic cell-cell and cell-ECM interactions exert different effects on hepatocyte functions and phenotypes.

Downregulation of transgelin blocks interleukin-8 utilization and suppresses vasculogenic mimicry in breast cancer cells

Vasculogenic mimicry (VM) is a non-classical mechanism recently described in many tumors, whereby cancer cells, rather than endothelial cells, form blood vessels. Transgelin is an actin-binding protein that has been implicated in multiple stages of cancer development. In this study, we investigated the role of transgelin in VM and assessed its effect on the expression of endothelial and angiogenesis-related genes during VM in MDA-MB-231 breast cancer cells. We confirmed the ability of MDA-MB-231 cells to undergo VM through a tube formation assay. Flow cytometry analysis revealed an increase in the expression of the endothelial-related markers VE-cadherin and CD34 in cells that underwent VM, compared with those growing in a monolayer, which was confirmed by immunocytochemistry. We employed siRNA to silence transgelin, and knockdown efficiency was determined by western blot analyses. Downregulation of transgelin suppressed cell proliferation and tube formation, but increased IL-8 levels in Matrigel cultures. RT-PCR analyses revealed that the expression of IL-8, VE-cadherin, and CD34 was unaffected by transgelin knockdown, indicating that increased IL-8 expression was not due to enhanced transcriptional activity. More importantly, the inhibition of IL-8/CXCR2 signaling also resulted in suppression of VM with increased IL-8 levels, confirming that increased IL-8 levels after transgelin knockdown was due to inhibition of IL-8 uptake. Our findings indicate that transgelin regulates VM by enhancing IL uptake. These observations are relevant to the future development of efficient antivascular agents. Impact statement Vasculogenic mimicry (VM) is an angiogenic-independent mechanism of blood vessel formation whereby aggressive tumor cells undergo formation of capillary-like structures. Thus, interventions aimed at angiogenesis might not target the entire tumor vasculature. A more holistic approach is therefore needed in the development of improved antivascular agents. Transgelin, an actin-binding protein, has been associated with multiple stages of cancer development such as proliferation, migration and invasion, but little is known about its role in vasculogenic mimicry. We present here, an additional mechanism by which transgelin promotes malignancy by way of its association with the occurrence of VM. Although transgelin knockdown did not affect the transcript levels of most of the angiogenesis-related genes in this study, it was associated with the inhibition of the uptake of IL-8, accompanied by suppressed VM, indicating that transgelin is required for VM. These observations are relevant to the future development of efficient antivascular agents.

Dual-Blocking of PI3K and mTOR Improves Chemotherapeutic Effects on SW620 Human Colorectal Cancer Stem Cells by Inducing Differentiation

Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs.

Transgelin increases metastatic potential of colorectal cancer cells in vivo and alters expression of genes involved in cell motility

Background

Transgelin is an actin-binding protein that promotes motility in normal cells. Although the role of transgelin in cancer is controversial, a number of studies have shown that elevated levels correlate with aggressive tumor behavior, advanced stage, and poor prognosis. Here we sought to determine the role of transgelin more directly by determining whether experimental manipulation of transgelin levels in colorectal cancer (CRC) cells led to changes in metastatic potential in vivo.

Methods

Isogenic CRC cell lines that differ in transgelin expression were characterized using in vitro assays of growth and invasiveness and a mouse tail vein assay of experimental metastasis. Downstream effects of transgelin overexpression were investigated by gene expression profiling and quantitative PCR.

Results

Stable overexpression of transgelin in RKO cells, which have low endogenous levels, led to increased invasiveness, growth at low density, and growth in soft agar. Overexpression also led to an increase in the number and size of lung metastases in the mouse tail vein injection model. Similarly, attenuation of transgelin expression in HCT116 cells, which have high endogenous levels, decreased metastases in the same model. Investigation of mRNA expression patterns showed that transgelin overexpression altered the levels of approximately 250 other transcripts, with over-representation of genes that affect function of actin or other cytoskeletal proteins. Changes included increases in HOOK1, SDCCAG8, ENAH/Mena, and TNS1 and decreases in EMB, BCL11B, and PTPRD.

Conclusions

Increases or decreases in transgelin levels have reciprocal effects on tumor cell behavior, with higher expression promoting metastasis. Chronic overexpression influences steady-state levels of mRNAs for metastasis-related genes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2105-8) contains supplementary material, which is available to authorized users.

Messenger RNA profile analysis deciphers new Esrrb responsive genes in prostate cancer cells

Background

Orphan nuclear receptor estrogen related receptor β (Esrrb or ERRβ) is well known in stem cells and early embryonic development. However, little is known about its function in cancer.

Method

We investigated the mRNA profile alterations induced by Esrrb expression and its synthetic ligand DY131 in human prostate cancer DU145 cells via RNA-Seq analysis.

Results

We distinguished 67 mRNAs differentially expressed by Esrrb alone. Although DY131 alone did not change any gene, treatment of DY131 in the presence of Esrrb altered 1161 mRNAs. These observations indicated Esrrb had both ligand-independent and ligand-dependent activity. When Esrrb was expressed, DY131 treatment further regulated 15 Esrrb-altered mRNAs. DY131 acted as an antagonist for 11 of 15 mRNAs (wdr52, f13a1, pxdn, spns2, loc100506599, tagln, loc441454, tkel1, sema3f, zcwpw2, sdc2) and as an agonist for 4 of the 15 mRNAs (rarres3, oasl, padi2, ddx60). Gene ontology analyses showed altered genes are related to transcription and translation regulation, cell proliferation and apoptosis regulation, and cellular metabolism.

Conclusion

Our results characterized mRNA profiles in DU145 prostate cancer cells driven by Esrrb expression and Esrrb ligand DY131, and provided multiple markers to characterize Esrrb’s function in Esrrb research.

Electronic supplementary material

The online version of this article (doi:10.1186/s12867-015-0049-1) contains supplementary material, which is available to authorized users.

Increased Expression of Tissue/Salivary Transgelin mRNA Predicts Poor Prognosis in Patients with Oral Squamous Cell Carcinoma (OSCC)

Background

Transgelin is supposed to be a tumor suppression gene and it is down-regulated in a variety of human cancers. However, the role of transgelin in different cancers is still very controversial. In addition, currently little information is available the relationship between transgelin and Oral Squamous Cell Carcinoma (OSCC).

Material/Methods

Western Blotting was performed to test the transgelin protein expression level in OSCC tissues and adjacent normal tissues. Real-time PCR was used to examine the expression level of transgelin mRNA in tissue, serum and saliva of OSCC patients and negative controls. The correlation between tissue and salivary transgelin mRNA expression level with a variety of clinical parameters was further studied.

Results

Transgelin protein expression was increased in OSCC patients compared with healthy individuals. Similarly, the expression level of both tissue and salivary transgelin mRNA were increased significantly in patients with OSCC in comparison with normal controls. However, little difference of serum transgelin mRNA expression was found between the OSCC patients and healthy controls. In addition, overexpression of tissue or salivary transgelin was closely associated with various clinical parameters including poorer overall survival. Furthermore, our results showed that tissue and salivary transgelin mRNA were independent prognosis factors for OSCC.

Conclusions

The expressions level of tissue mRNA and protein were increased in OSCC patients. Both tissue and salivary transgelin mRNA were closely correlated with various important clinicopathological parameters and were independent prognosis factors for OSCC, indicating they might serve promising biomarkers for OSCC.

Profilin 2 promotes migration, invasion, and stemness of HT29 human colorectal cancer stem cells

We investigated the role of profilin 2 in the stemness, migration, and invasion of HT29 cancer stem cells (CSCs). Increased and decreased levels of profilin 2 significantly enhanced and suppressed the self-renewal, migration, and invasion ability of HT29 CSCs, respectively. Moreover, profilin 2 directly regulated the expression of stemness markers (CD133, SOX2, and β-catenin) and epithelial mesenchymal transition (EMT) markers (E-cadherin and snail). CD133 and β-catenin were up-regulated by overexpression of profilin 2 and down-regulated by depletion of profilin 2. SOX2 was decreased by profilin 2 depletion. E-cadherin was not influenced by profilin 2- overexpression but increased by profilin 2- knockdown. The expression of snail was suppressed by profilin 2- knockdown. We speculated that stemness and the EMT are closely linked through profilin 2-related pathways. Therefore, this study indicates that profilin 2 affects the metastatic potential and stemness of colorectal CSCs by regulating EMT- and stemness-related proteins.

Transgelin: a potentially useful diagnostic marker differentially expressed in triple-negative and non-triple-negative breast cancers

Triple negative (TN) (estrogen receptor [ER], progesterone receptor [PR] and HER2-) are highly aggressive, rapidly growing, hormone-unresponsive tumors diagnosed at later stage that affect younger women with shorter overall survival. Most TN tumors are of the basal type. For the remainder, identification of target markers for effective treatment strategies remains a challenge. Transgelin (TGLN) is a 22-kd actin-binding protein of the calponin family. It is one of the earliest markers of smooth muscle differentiation. TGLN has been shown to have important biologic activities including regulating muscle fiber contractility, cell migration, and tumor suppression. We examined TGLN expression in the different molecular subtypes of breast cancer. TGLN expression was examined as a function of tumor size, grade, histologic type, lymph node status, patients' age and overall survival, ER, PR, HER2, and Ki-67 in 101 tumors that included 35 luminal A, 28 luminal B, 4 HER2, and 34 TN types. TGLN positivity (defined as 2+ or 3+) was associated with more aggressive tumors (10% of grade I/II tumors were TGLN+ versus 53% of grade III tumors; P < .001), high Ki-67 count, and low ER and PR expression (P < .001) but not with tumor size, age, or lymph node metastasis. TN (n = 34) tumors were 7.7 times more likely to be TGLN+ than non-TN (n = 67) tumors (77% versus 10%, respectively; P < .001). TGLN may be an excellent diagnostic marker of TN tumors and could be useful in stratification of patients. TGLN may also prove a potential target for future treatment strategies.

Alpha-fetoprotein activates AKT/mTOR signaling to promote CXCR4 expression and migration of hepatoma cells

CXCR4, stromal cell-derived factor-1α(SDF 1α) receptor, stimulates growth and metastasis of hepatocellular carcinoma (HCC). Alpha-fetoprotein(AFP) governs the expression of some metastasis-related genes. Here we report that AFP and CXCR4 levels correlated in HCC tissues. AFP-expressing vectors induced CXCR4. In agreement, AFP depletion by siRNA decreased CXCR4. AFP co-localized and interacted with PTEN, thus inducing CXCR4 by activating AKT(Ser473) phosphorylation. In turn, phospho-mTOR(Ser2448) entered the nucleus and bound the CXCR4 gene promoter. Thus, AFP promoted migration of HCC cells. In concusion, AFP induced CXCR4 by activating the AKT/mTOR signal pathway.

The downregulation of miR-144 is associated with the growth and invasion of osteosarcoma cells through the regulation of TAGLN expression

Alterations in the expression of microRNAs (miRNAs or miRS) have been implicated in the pathogenesis of the majority of human malignancies, and the dysregulation of microRNA-144 (miR-144) has been associated with several diseases. However, the potential involvement of miR-144 in osteosarcoma, a common malignant bone tumor in children and adolescents with a high risk of relapse and metastasis, has not yet been fully investigated. In the present study, we examined the expression and roles of miRNAs in osteosarcoma as potential diagnostic markers and therapeutic targets, and we focused on miR-144 due to its known involvement in osteogenesis. We demonstrate that miR-144 is downregulated in osteosarcoma cell lines and primary human osteosarcoma tissue samples and that its ectopic expression inhibits osteosarcoma cell proliferation and invasion. We identified TAGLN as a downstream target of miR-144 and demonstrated that its expression is upregulated in osteosarcoma cell lines and tumor tissue and is inversely correlated with miR-144 expression. Our results indicate that miR-144 may regulate osteosarcoma cell proliferation and invasion by downregulating its target gene, TAGLN, suggesting that miR-144 may be a potential therapeutic target for the treatment of osteosarcoma.

Comprehensive characterization of glioblastoma tumor tissues for biomarker identification using mass spectrometry-based label-free quantitative proteomics

Cancer is a complex disease; glioblastoma (GBM) is no exception. Short survival, poor prognosis, and very limited treatment options make it imperative to unravel the disease pathophysiology. The critically important identification of proteins that mediate various cellular events during disease is made possible with advancements in mass spectrometry (MS)-based proteomics. The objective of our study is to identify and characterize proteins that are differentially expressed in GBM to better understand their interactions and functions that lead to the disease condition. Further identification of upstream regulators will provide new potential therapeutic targets. We analyzed GBM tumors by SDS-PAGE fractionation with internal DNA markers followed by liquid chromatography-tandem mass spectrometry (MS). Brain tissue specimens obtained for clinical purposes during epilepsy surgeries were used as controls, and the quantification of MS data was performed by label-free spectral counting. The differentially expressed proteins were further characterized by Ingenuity Pathway Analysis (IPA) to identify protein interactions, functions, and upstream regulators. Our study identified several important proteins that are involved in GBM progression. The IPA revealed glioma activation with z score 2.236 during unbiased core analysis. Upstream regulators STAT3 and SP1 were activated and CTNNα was inhibited. We verified overexpression of several proteins by immunoblot to complement the MS data. This work represents an important step towards the identification of GBM biomarkers, which could open avenues to identify therapeutic targets for better treatment of GBM patients. The workflow developed represents a powerful and efficient method to identify biomarkers in GBM.

Smooth muscle differentiation identifies two classes of poorly differentiated pleomorphic sarcomas with distinct outcome

The clinical relevance of accurately diagnosing pleomorphic sarcomas has been shown, especially in cases of undifferentiated pleomorphic sarcomas with myogenic differentiation, which appear significantly more aggressive. To establish a new smooth muscle differentiation classification and to test its prognostic value, 412 sarcomas with complex genetics were examined by immunohistochemistry using four smooth muscle markers (calponin, h-caldesmon, transgelin and smooth muscle actin). Two tumor categories were first defined: tumors with positivity for all four markers and tumors with no or incomplete phenotypes. Multivariate analysis demonstrated that this classification method exhibited the strongest prognostic value compared with other prognostic factors, including histological classification. Secondly, incomplete or absent smooth muscle phenotype tumor group was then divided into subgroups by summing for each tumor the labeling intensities of all four markers for each tumors. A subgroup of tumors with an incomplete but strong smooth muscle differentiation phenotype presenting an intermediate metastatic risk was thus identified. Collectively, our results show that the smooth muscle differentiation classification method may be a useful diagnostic tool as well as a relevant prognostic tool for undifferentiated pleomorphic sarcomas.

Transgelins, cytoskeletal proteins implicated in different aspects of cancer development

Transgelin is an abundant protein of smooth muscle cells, where its role has been primarily studied. As a protein affecting dynamics of the actin cytoskeleton via stabilization of actin filaments, transgelin is both directly and indirectly involved in many cancer-related processes such as migration, proliferation, differentiation or apoptosis. Transgelin was previously reviewed as a tumor suppressor; however, recent data based on a number of proteomics studies indicate its pro-tumorigenic role, for example, in colorectal or hepatocellular cancer. We summarize these contradictory observations in both clinical and functional proteomics projects and analyze the role of transgelin in tumors in detail. Generally, the expression and biological role of transgelin seem to differ among various types of tumor cells and stroma, and possibly change during tumor progression. We also overview the recent data on transgelin-2, a sequence homolog of transgelin, whose role in the tumor development might be contradictory to the role of transgelin.

Quantitative proteomic analysis in HCV-induced HCC reveals sets of proteins with potential significance for racial disparity

Background

The incidence and mortality of hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) is higher in African Americans (AA) than other racial/ethnic groups in the U.S., but the reasons for this disparity are unknown. There is an urgent need for the discovery of novel molecular signatures for HCV disease progression to understand the underlying biological basis for this cancer rate disparity to improve the clinical outcome.

Methods

We performed differential proteomics with isobaric labeling tags for relative and absolute quantitation (iTRAQ) and MS/MS analysis to identify proteins differentially expressed in cirrhotic (CIR) and HCC as compared to normal tissues of Caucasian American (CA) patients. The raw data were analyzed using the ProteinPilot v3.0. Searches were performed against all known sequences populating the Swiss-Prot, Refseq, and TrEMBL databases. Quality control analyses were accomplished using pairwise correlation plots, boxplots, principal component analysis, and unsupervised hierarchical clustering. Supervised analysis was carried out to identify differentially expressed proteins. Candidates were validated in independent cohorts of CA and AA tissues by qRT-PCR or Western blotting.

Results

A total of 238 unique proteins were identified. Of those, around 15% were differentially expressed between normal, CIR & HCC groups. Target validation demonstrates racially distinct alteration in the expression of certain proteins. For example, the mRNA expression levels of transferrin (TF) were 2 and18-fold higher in CIR and HCC in AA as compared to CA. Similarly; the expression of Apolipoprotein A1 (APOA1) was 7-fold higher in HCC of AA. This increase was mirrored in the protein expression levels. Interestingly, the level of hepatocyte nuclear factor4α (HNF4α) protein was down regulated in AA, whereas repression of transcription is seen more in CA compared to AA. These data suggest that racial disparities in HCC could be a consequence of differential dysregulation of HNF4α transcriptional activity.

Conclusion

This study identifies novel molecular signatures in HCV-induced HCC using iTRAQ-based tissue proteomics. The proteins identified will further enhance a molecular explanation to the biochemical mechanism(s) that may play a role in HCC racial disparities.

Extracellular matrix composition significantly influences pancreatic stellate cell gene expression pattern: role of transgelin in PSC function

Activated pancreatic stellate cells (PSCs) are responsible for the fibrotic matrix of chronic pancreatitis and pancreatic cancer. In vitro protocols examining PSC biology have usually involved PSCs cultured on plastic, a nonphysiological surface. However, PSCs cultured on physiological matrices, e.g., Matrigel (normal basement membrane) and collagen (fibrotic pancreas), may have distinctly different behaviors compared with cells cultured on plastic. Therefore, we aimed to 1) compare PSC gene expression after culture on plastic, Matrigel, and collagen I; 2) validate the gene array data for transgelin, the most highly dysregulated gene in PSCs grown on activating vs. nonactivating matrices, at mRNA and protein levels; 3) examine the role of transgelin in PSC function; and 4) assess transgelin expression in human chronic pancreatitis sections. Culture of PSCs on different matrices significantly affected their gene expression pattern. 146, 619, and 432 genes, respectively, were differentially expressed (P < 0.001) in PSCs cultured on collagen I vs. Matrigel, Matrigel vs. plastic, and collagen I vs. plastic. The highest fold change (12.5-fold upregulation) in gene expression in cells on collagen I vs. Matrigel was observed for transgelin (an actin stress fiber-associated protein). Transgelin was significantly increased in activated PSCs vs. quiescent PSCs. Silencing transgelin expression decreased PSC proliferation and also reduced platelet-derived growth factor-induced PSC migration. Notably, transgelin was highly expressed in chronic pancreatitis in stromal areas and periacinar spaces but was absent in acinar cells. These findings suggest that transgelin is a potentially useful target protein to modulate PSC function so as to ameliorate pancreatic fibrosis.

Proteomic profiling and interactome analysis of ER-positive/HER2/neu negative invasive ductal carcinoma of the breast: towards proteomics biomarkers

Breast cancer, especially ER positive/HER2/neu negative IDC, is the predominant subtype of invasive ductal carcinoma. Although proteomic approaches have been used towards biomarker discovery in clinical breast cancer, ER positive/HER2/neu negative IDC is the least studied subtype. To discover biomarkers, as well as to understand the molecular events associated with disease progression of estrogen receptor positive/HER2/neu negative subtype of invasive ductal carcinoma, differential protein expression profiling was performed by using LC-MS(E) (MS at elevated energy). A total of 118 proteins were identified, of which 26 were differentially expressed. These identified proteins were functionally classified and their interactions and coexpression were analyzed by using bioinformatic tools PANTHER (Protein Analysis THrough Evolutionary Relationships) and STRING (Search Tool for the Retrieval of Interacting Genes). These proteins were found to be upregulated and were involved in cytoskeletal organization, calcium binding, and stress response. Interactions of annexin A5, actin, S100 A10, glyceraldehyde 3 phosphate dehydrogenase, superoxide dismutase 1, apolipoprotein, fibrinogen, and heat shock proteins were prominent. Differential expression of these proteins was validated by two-dimensional gel electrophoresis and Western blot analysis. The cluster of these proteins may serve as a signature profile for estrogen receptor positive/ HER2/neu negative subtype.

The pluripotency factor nanog promotes breast cancer tumorigenesis and metastasis

Nanog is a transcription factor required for maintaining the pluripotency of embryonic stem cells, and is not expressed in most normal adult tissues. However, recent studies have indicated that Nanog is overexpressed in many types of human cancers, including breast cancer. To elucidate the physiological roles of Nanog in tumorigenesis, we developed an inducible Nanog transgenic mouse model, in which the expression of Nanog in adult tissues can be induced via LoxP/Cre-mediated deletion. Our findings indicate that overexpression of Nanog in the mammary gland is not sufficient to induce mammary tumor. However, when coexpressed with Wnt-1 in the mouse mammary gland, it promotes mammary tumorigenesis and metastasis. In this context, Nanog promotes the migration and invasion of breast cancer cells. Microarray analysis has shown that the ectopic expression of Nanog deregulates the expression of numerous genes associated with tumorigenesis and metastasis, such as the PDGFRα gene. Our findings demonstrate the involvement of Nanog in breast cancer metastasis, and provide the basis for the reported correlation between Nanog expression and poor prognosis of human breast cancer patients. As Nanog is not expressed in most adult tissues, these findings identify Nanog as a potential therapeutic target in the treatment of Nanog-expressing metastatic breast cancer.

iTRAQ based quantitative proteomics approach validated the role of calcyclin binding protein (CacyBP) in promoting colorectal cancer metastasis

Keeping continuity with our previous study that revealed direct correlations between CRC metastasis and enhanced CacyBP protein levels, here we attempt to improve our understanding of the mechanisms involved within this enigmatic process. Overexpression of CacyBP (CacyBP-OE) in primary CRC cell and its knock down (CacyBP-KD) in the metastatic CRC cells revealed (through phenotypic studies) the positive impact of the protein on metastasis. Additionally, two individual 4-plex iTRAQ based comparative proteomics experiments were carried out on the CacyBP-OE and CacyBP-KD cells, each with two biological replicates. Mining of proteomics data identified total 279 (63.80% up-regulated and 36.20% down-regulated) proteins to be significantly altered in expression level for the OE set and in the KD set, this number was 328 (48.78% up-regulated and 51.22% down-regulated). Functional implications of these significantly regulated proteins were related to metastatic phenotypes such as cell migration, invasion, adhesion and proliferation. Gene ontology analysis identified integrin signaling as the topmost network regulated within CacyBP-OE. Further detection of caveolar mediated endocytosis in the top hit list correlated this phenomenon with the dissociation of integrins from the focal adhesion complex which are known to provide the traction force for cell movement when transported back to the leading edge. This finding was further supported by the data obtained from CacyBP-KD data set showing down-regulation of proteins necessary for integrin endocytosis. Furthermore, intracellular calcium levels (known to influence integrin mediated cell migration) were found to be lowered in CacyBP-KD cells indicating decreased cell motility and vice versa for the CacyBP-OE cells. Actin nucleation by ARP-WASP complex, known to promote cell migration, was also identified as one of the top regulated pathways in CacyBP-OE cells. In short, this study presents CacyBP as a promising candidate biomarker for CRC metastasis and also sheds light on the underlying molecular mechanism by which CacyBP promotes CRC metastasis.

Stromal fibroblasts in the microenvironment of gastric carcinomas promote tumor metastasis via upregulating TAGLN expression

Background

Fibroblasts play a critical role in tumorigenesis, tumor progression and metastasis. However, their detailed molecular characteristics and clinical significance are still elusive. TAGLN is an actin-binding protein that plays an important role in tumorigenesis.

Results

We investigated the interaction between cancer cells and the tumor microenvironment to determine how the fibroblasts from human gastric carcinoma facilitate tumorigenesis through TAGLN. QRT-PCR and Western blot indicated that TAGLN expression was upregulated in gastric carcinoma-associated fibroblasts (CAFs) that promote gastric cancer cell migration and invasion. Using small interfering RNA (siRNA), we found that CAFs enhanced tumor metastasis through upregulated TAGLN in vitro and in vivo. The expression of matrix metalloproteinase-2 (MMP-2) was significantly lower after TAGLN knock-down by siRNA. TAGLN levels were elevated in human gastric cancer stroma than normal gastric stroma and associated with differentiation and lymph node metastasis of gastric cancer.

Conclusion

CAFs may promote gastric cancer cell migration and invasion via upregulating TAGLN and TAGLN induced MMP-2 production.

Upregulation of transgelin is an independent factor predictive of poor prognosis in patients with advanced pancreatic cancer

Transgelin is a known actin-binding protein, which plays a role in regulating the functions of smooth muscle cells or fibroblasts. Recent evidence indicates that transgelin is involved in diverse human cancers, yet its role in pancreatic cancer remains unclear. We therefore evaluated the expression characteristics and function of transgelin in pancreatic cancer. Immunohistochemical analysis of benign (n = 30 patients) and malignant (n = 114 patients) pancreatic ductal cells showed significantly higher transgelin staining in malignant cells. Lymph node metastasis (P = 0.026) and diabetes (P = 0.041) were shown to significantly correlate with transgelin protein expression. Patients with high transgelin expression showed a shorter 5-year overall survival and a lower tumor-specific survival than those with low transgelin expression. Multivariate analysis revealed that transgelin was an independent factor affecting pancreatic tumor-specific survival (P = 0.025). In vitro, RNA interference-mediated transgelin knockdown resulted in inhibition of pancreatic cancer cell proliferation, migration and invasion. Depletion of transgelin expression could suppress pancreatic tumorigenicity and tumor growth in vivo, and produce enhanced cytotoxic effects of gemcitabine on pancreatic cancer cells both in vitro and in vivo. Our results indicate that transgelin plays a promoting role in tumor progression, and appears to be a novel prognostic marker for advanced pancreatic cancer.

Proteomics in studying cancer stem cell biology

Normal multipotent tissue stem cells (SCs) are the driving force behind tissue turnover and repair. The cancer stem cell theory holds that tumors also contain stem-like cells that drive tumor growth and metastasis formation. However, very little is known about the regulation of SC maintenance pathways in cancer and how these are affected by cancer-specific genetic alterations and by treatment. Proteomics is emerging as a powerful tool to identify the signaling complexes and pathways that control multi- and pluri-potency and SC differentiation. Here, the authors review the novel insights that these studies have provided and present a comprehensive strategy for the use of proteomics in studying cancer SC biology.