Thymosin-beta4 regulates motility and metastasis of malignant mouse fibrosarcoma cells

Thymosin β4 and β10 Expression in Human Organs during Development: A Review

This review summarizes the results of a series of studies performed by our group with the aim to define the expression levels of thymosin β4 and thymosin β10 over time, starting from fetal development to different ages after birth, in different human organs and tissues. The first section describes the proteomics investigations performed on whole saliva from preterm newborns and gingival crevicular fluid, which revealed to us the importance of these acidic peptides and their multiple functions. These findings inspired us to start an in-depth investigation mainly based on immunochemistry to establish the distribution of thymosin β4 and thymosin β10 in different organs from adults and fetuses at different ages (after autopsy), and therefore to obtain suggestions on the functions of β-thymosins in health and disease. The functions of β-thymosins emerging from these studies, for instance, those performed during carcinogenesis, add significant details that could help to resolve the nowadays so-called "β-thymosin enigma", i.e., the potential molecular role played by these two pleiotropic peptides during human development.

Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties

Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.

PTEN/AKT upregulation of TMSB10 contributes to lung cancer cell growth and predicts poor survival of the patients

PTEN/AKT signaling cascade is frequently activated in various cancers, including lung cancer. The downstream effector of this signaling cascade is poorly understood. β-Thymosin 10 (TMSB10) functions as an oncogene or tumor suppressors in cancers, whereas its significance in lung cancer remains unknown. In this study, we showed that the activation of PTEN/AKT signaling promoted the expression of TMSB10. Based on the TCGA database, TMSB10 was upregulated in lung cancer tissues and its overexpression was correlated with poor prognosis of lung cancer patients. Functional experiments demonstrated that TMSB10 knockdown suppressed, while its overexpression promoted the proliferation, growth, and migration of lung cancer cells. Apoptosis and epithelial-mesenchymal transition were also regulated by TMSB10. We therefore suggest that TMSB10 is a novel oncogene for lung cancer. Targeting TMSB10 may benefit lung cancer patients with activated PTEN/AKT signaling.

Inflammation-Related Carcinogenesis: Lessons from Animal Models to Clinical Aspects

Simple Summary

In multicellular organisms, inflammation is the body’s most primitive and essential protective response against any external agent. Inflammation, however, not only causes various modern diseases such as cardiovascular disorders, neurological disorders, autoimmune diseases, metabolic syndrome, infectious diseases, and cancer but also shortens the healthy life expectancy. This review focuses on the onset of carcinogenesis due to chronic inflammation caused by pathogen infections and inhalation/ingestion of foreign substances. This study summarizes animal models associated with inflammation-related carcinogenesis by organ. By determining factors common to inflammatory carcinogenesis models, we examined strategies for the prevention and treatment of inflammatory carcinogenesis in humans.

Abstract

Inflammation-related carcinogenesis has long been known as one of the carcinogenesis patterns in humans. Common carcinogenic factors are inflammation caused by infection with pathogens or the uptake of foreign substances from the environment into the body. Inflammation-related carcinogenesis as a cause for cancer-related death worldwide accounts for approximately 20%, and the incidence varies widely by continent, country, and even region of the country and can be affected by economic status or development. Many novel approaches are currently available concerning the development of animal models to elucidate inflammation-related carcinogenesis. By learning from the oldest to the latest animal models for each organ, we sought to uncover the essential common causes of inflammation-related carcinogenesis. This review confirmed that a common etiology of organ-specific animal models that mimic human inflammation-related carcinogenesis is prolonged exudation of inflammatory cells. Genotoxicity or epigenetic modifications by inflammatory cells resulted in gene mutations or altered gene expression, respectively. Inflammatory cytokines/growth factors released from inflammatory cells promote cell proliferation and repair tissue injury, and inflammation serves as a “carcinogenic niche”, because these fundamental biological events are common to all types of carcinogenesis, not just inflammation-related carcinogenesis. Since clinical strategies are needed to prevent carcinogenesis, we propose the therapeutic apheresis of inflammatory cells as a means of eliminating fundamental cause of inflammation-related carcinogenesis.

Di-(2-ethylhexyl) phthalate-induced tumor growth is regulated by primary cilium formation via the axis of H2O2 production-thymosin beta-4 gene expression

Di-(2-ethylhexyl) phthalate (DEHP) that is one of the most commonly used phthalates in manufacturing plastic wares regulates tumorigenesis. Thymosin beta-4 (TB4), an actin-sequestering protein, has been reported as a novel regulator to form primary cilia that are antenna-like organelles playing a role in various physiological homeostasis and pathological development including tumorigenesis. Here, we investigated whether DEHP affects tumor growth via primary cilium (PC) formation via the axis of TB4 gene expression and the production of reactive oxygen species (ROS). Tumor growth was increased by DEHP treatment that enhanced TB4 expression, PC formation and ROS production. The number of cells with primary cilia was enhanced time-dependently higher in HeLa cells incubated in the culture medium with 0.1% fetal bovine serum (FBS). The number of cells with primary cilia was decreased by the inhibition of TB4 expression. The incubation of cells with 0.1% FBS enhanced ROS production and the transcriptional activity of TB4 that was reduced by ciliobrevin A (CilioA), the inhibitor of ciliogenesis. ROS production was decreased by catalase treatment but not by mito-TEMPO, which affected to PC formation with the same trend. H₂O₂ production was reduced by siRNA-based inhibition of TB4 expression. H₂O₂ also increased the number of ciliated cells, which was reduced by siRNA-TB4 or the co-incubation with CilioA. Tumor cell viability was maintained by ciliogenesis, which was correlated with the changes of intracellular ATP amount rather than a simple mitochondrial enzyme activity. TB4 overexpression enhanced PC formation and DEHP-induced tumor growth. Taken together, data demonstrate that DEHP-induced tumor growth might be controlled by PC formation via TB4-H₂O₂ axis. Therefore, it suggests that TB4 could be a novel bio-marker to expect the risk of DEHP on tumor growth.

The entangled relationship between cilia and actin

Primary cilia are microtubule-based sensory cell organelles that are vital for tissue and organ development. They act as an antenna, receiving and transducing signals, enabling communication between cells. Defects in ciliogenesis result in severe genetic disorders collectively termed ciliopathies. In recent years, the importance of the direct and indirect involvement of actin regulators in ciliogenesis came into focus as it was shown that F-actin polymerisation impacts ciliation. The ciliary basal body was further identified as both a microtubule and actin organising centre. In the current review, we summarize recent studies on F-actin in and around primary cilia, focusing on different actin regulators and their effect on ciliogenesis, from the initial steps of basal body positioning and regulation of ciliary assembly and disassembly. Since primary cilia are also involved in several intracellular signalling pathways such as planar cell polarity (PCP), subsequently affecting actin rearrangements, the multiple effectors of this pathway are highlighted in more detail with a focus on the feedback loops connecting actin networks and cilia proteins. Finally, we elucidate the role of actin regulators in the development of ciliopathy symptoms and cancer.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

Thymosin‑β 4 induces angiogenesis in critical limb ischemia mice via regulating Notch/NF‑κB pathway

Thymosin‑β 4 (Tβ4) has been reported to exert a pro‑angogenic effect on endothelial cells. However, little is known on the role and underlying mechanisms of Tβ4 on critical limb ischemia (CLI). The present study aimed therefore to investigate the mechanisms and pro‑angiogenic effects of Tβ4 in CLI mice. Tβ4 overexpression lentiviral vector was first transfected into HUVEC and CLI mice model, and inhibitors of Notch pathway (DAPT) and NF‑κB pathway (BMS) were also applied to HUVEC and CLI mice. Subsequently, MTT, tube formation and wound healing assays were used to determine the cell viability, angiogenesis and migratory ablity of HUVEC, respectively. Western blotting, reverse transcription, quantitative PCR, immunofluorescence and immunohistochemistry were used to detect the expression of the angiogenesis‑related factors angiopoietin‑2 (Ang2), TEK receptor tyrosine kinase 2 (tie2), vascular endothelial growth factor A (VEGFA), CD31 and α‑smooth muscle actin (α‑SMA) and the Notch/NF‑κB pathways‑related factors NOTCH1 intracellular domain (N1ICD), Notch receptor 3 (Notch3), NF‑κB and p65 in HUVEC or CLI mice muscle tissues. The results demonstrated that Tβ4 not only enhanced the cell viability, angiogenesis and migratory ability of HUVEC but also promoted the expression of Ang2, tie2, VEGFA, N1ICD, Notch3, NF‑κB, and phosphorylated (p)‑p65 in HUVEC. In addition, Tβ4 promoted the expression of CD31, α‑SMA Ang2, tie2, VEGFA, N1ICD and p‑p65 in CLI mice muscle tissues. Treatment with DAPT and BMS had opposite effects of Tβ4, whereas Tβ4 reversed the effect of DAPT and BMS. The findings from the present study suggested that Tβ4 may promote angiogenesis in CLI mice via regulation of Notch/NF‑κB pathways.

Multiple functions of thymosin β4 in the pearl oyster Pinctada fucata suggest its multiple potential roles in artificial pearl culture

Thymosin β4 is a multifunctional protein in vertebrates that participates in physiological processes, such as wound healing, immune response, cell proliferation and migration. We assessed the multifarious roles of this small peptide in Pinctada fucata, an oyster commonly used in pearl culture in China. Our results showed that when P. fucata was challenged by bacterial pathogens or LPS, the relative expression level of Pfthymosin β4 mRNA was significantly up-regulated, suggesting its involvement in immune response of the animal. Recombinant Pfthymosin β4 (rPfthymosin β4) was produced and showed in vitro different antibacterial activities against different pathogenic bacteria; the inhibitory effect of rPfthymosin β4 on bacterial growth was relatively stronger in the broth culture than agar culture. The overexpression of Pfthymosin β4 in Escherichia coli BL21(DE3) cells could improve their resistance to Cu²⁺, Zn²⁺, Cd²⁺, and H₂O₂, suggesting that Pfthymosin β4 is likely involved with antioxidant. rPfthymosin β4 also significantly promoted the proliferation and migration of mouse aortic vascular smooth muscle cells as indicated by MTT assay and cell scratch assay, respectively. In addition, chemically synthesized or recombinant Pfthymosin β4 could transiently increase the circulating total hemocytes counts but down-regulated by RNAi in P. fucata. Taking together above results and previous studies suggested that Pfthymosin β4 is potentially able to promote wound healing through enhancing antibacterial activity and antioxidant capacity, promotion of cell proliferation and migration, and increase of circulating hemocytes in P. fucata due to nucleus implantation injury. Thus, the future of recombinant Pfthymosin β4 should be promising in the culture of pearls in P. fucata.

TMSB10 acts as a biomarker and promotes progression of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most common urological malignancies. Identifying novel biomarkers and investigating the underlying mechanism of ccRCC development will be crucial to the management and treatment of ccRCC in patients. Thymosin b10 (TMSB10), a member of the thymosin family, is involved in various physiological processes, including tissue regeneration and inflammatory regulation. Moreover, it has been found to be upregulated in many types of carcinoma. However, its roles in ccRCC remain to be elucidated. The present study aimed to explore the expression of TMSB10 in ccRCC through mining The Cancer Genome Atlas (TCGA) and Oncomine databases, and to investigate the association between TMSB10 expression and clinicopathological factors. Furthermore, immunohistochemistry assays and western blotting were conducted to verify TMSB10 expression levels in human ccRCC tissues and cell lines. Functional analyses were also performed to identify the roles of TMSB10 in vitro. The results revealed that TMSB10 was significantly upregulated in RCC tissues and cell lines. The expression of TMSB10 was closely associated with various clinicopathological parameters. In addition, high expression of TMSB10 predicted poor clinical outcome. The receiver operating characteristic curve revealed that TMSB10 could sufficiently distinguish the tumor from normal kidney (area under the curve = 0.9543, P<0.0001). Furthermore, knockdown of TMSB10 impaired the proliferation of ccRCC cells, and attenuated cell and invasion in vitro. In addition, TMSB10 knockdown downregulated reduced the phosphorylation of PI3K and the expression of vascular endothelial growth factor. In conclusion, the present study demonstrated that high expression of TMSB10 could serve as a useful diagnostic and prognostic biomarker and a potential therapeutic target for ccRCC.

Thymosin β-4 is a novel regulator for primary cilium formation by nephronophthisis 3 in HeLa human cervical cancer cells

Thymosinβ-4(Tβ4) is an actin-sequestering protein involved in tumor malignancy. Primary cilia, microtubule-based organelles, are present in most eukaryotic cells, which might be related to tumor cell transformation. Here, we investigated whether ciliogenesis is affected by Tβ4 in HeLa human cervical cancer cells. The inhibition of Tβ4 attenuated primary cilia formation. The frequency of cilia was increased by Tβ4 overexpression. When yeast two-hybrid assay was performed by using Tβ4 as a bait, we rescued nephronophthisis 3(NPHP3), one of the components of primary cilia. Interaction of Tβ4 with NPHP3 in mammalian cells was confirmed by GST-pulldown assay. Their intracellular co-localization was observed by immunofluorescence staining at peripheral surface of cells. In addition, the number of ciliated cells was reduced by the inhibition of NPHP3. Moreover, NPHP3 expression was decreased by the inhibition of Tβ4 but it was increased by Tβ4 overexpression. Taken together, the results demonstrate that primary cilia formation could be regulated by Tβ4 through its interaction with NPHP3 and/or the control of NPHP3 expression. It suggests that Tβ4 is a novel regulator for primary cilia formation by NPHP3. It also suggests that tumorigenesis could be associated with inappropriate regulation of Tβ4 and/or NPHP3 expression to maintain primary cilia formation normally.

Comparative study of β-thymosin in two scallop species Argopecten irradians and Chlamys farreri

The β-thymosin (Tβ) proteins participate in numerous biological processes, such as cell proliferation and differentiation, anti-inflammatory and antimicrobial mechanism. To date, Tβ proteins have been well studied in vertebrates, especially mammals. While limited Tβ or Tβ-like proteins have been reported in invertebrates. Moreover, rare information of Tβ or Tβ-like proteins is available in scallop species yet. In the present study, two Tβ homologues, AiTβ and CfTβ, were identified and characterized from two scallop species bay scallop Argopecten irradians and Zhikong scallop Chlamys farreri. They were both 41 amino acid peptide and contained one THY domain, a highly conserved actin-binding motif and two conserved helix forming regions. Tissue distribution and expression profiles of their mRNA transcripts were roughly similar yet different in detail, while their recombinant proteins exhibited different immunomodulation activity on the downstream immune parameters. These results collectively indicated that the function of Tβ family in scallop were functionally differentiated.

Tumor suppressor miR-1 inhibits tumor growth and metastasis by simultaneously targeting multiple genes

Cancer progression depends on tumor growth and metastasis, which are activated or suppressed by multiple genes. An individual microRNA may target multiple genes, suggesting that a miRNA may suppress tumor growth and metastasis via simultaneously targeting different genes. However, thus far, this issue has not been explored. In the present study, the findings showed that miR-1 could simultaneously inhibit tumor growth and metastasis of gastric and breast cancers by targeting multiple genes. The results indicated that miR-1 was significantly downregulated in cancer tissues compared with normal tissues. The miR-1 overexpression led to cell cycle arrest in the G1 phase in gastric and breast cancer cells but not in normal cells. Furthermore, the miR-1 overexpression significantly inhibited the metastasis of gastric and breast cancer cells. An analysis of the underlying mechanism revealed that the simultaneous inhibition of tumor growth and metastasis mediated by miR-1 was due to the synchronous targeting of 6 miR-1 target genes encoding cyclin dependent kinase 4, twinfilin actin binding protein 1, calponin 3, coronin 1C, WAS protein family member 2 and thymosin beta 4, X-linked. In vivo assays demonstrated that miR-1 efficiently inhibited tumor growth and metastasis of gastric and breast cancers in nude mice. Therefore, our study contributed novel insights into the miR-1′s roles in tumorigenesis of gastric and breast cancers.

Global Proteomics-based Identification and Validation of Thymosin Beta-4 X-Linked as a Prognostic Marker for Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) represents a major health concern worldwide. We applied the matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) to analyze paired normal (N) and tumor (T) samples from head and neck squamous cell carcinoma as well as liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis in HNSCC cell lines to identify tumor-associated biomarkers. Our results showed a number of proteins found to be over-expressed in HNSCC. We identified thymosin beta-4 X-linked (TMSB4X) is one of the most significant candidate biomarkers. Higher TMSB4X expression in the tumor was found by N/T-paired HNSCC samples at both RNA and protein level. Overexpression of TMSB4X was found significantly associated with poor prognosis of overall survival (OS, P = 0.006) and recurrence-free survival (RFS, P = 0.013) in HNSCC patients. Silencing of TMSB4X expression in HNSCC cell line reduced the proliferation and invasion ability in vitro, as well as inhibited the cervical lymph node metastasis in vivo. Altogether, our global proteomics analysis identified that TMSB4X is a newly discovered biomarker in HNSCC whose functions resulted in enhanced proliferation and metastasis in vitro and in vivo. TMSB4X may be a potential therapeutic target for treating HNSCC patients.

Thymosin beta-4 overexpression correlates with high-risk groups in gastric gastrointestinal stromal tumors: A retrospective analysis by immunohistochemistry

BACKGROUND

Thymosin beta-4 (Tβ4) is a protein that is linked to a number of important biological actions and recently tumor progression and poor prognosis of some tumors. The aim of this study was to evaluate Tβ4 expression in gastric GISTs and correlate with some clinicopathological characteristics related with prognosis and clinical outcome in order to add further data to the current literature.

METHODS

Tβ4 antibody was applied to the 4μm-thick paraffin sections of 57 gastric GISTs by immunohistochemistry.

RESULTS

Tβ4 expression was found to be directly corrrelated with higher risk groups, tumor size, mitotic count, cellularity, and necrosis while it was inversely correlated with overall survival (OS) by univariate analysis (p=0.000, p=0.001, p=0.000, p=0.025, p=0.023, and p=0.042, respectively). The direct association between Tβ4 expression and risk groups were also supported by multivariate analysis (p=0.000, β=0.497, t=4.374).

CONCLUSION

Overexpression of Tβ4 was found to be related with predictive characteristics for tumor progression and adverse prognosis. Thus, we suggest that overexpression of Tβ4 might play a role in the progression of gastric GISTs and might be used as a potential prognostic tool as well as a target for novel therapies.

Increased Expression of Thymosin β4 Is Independently Correlated with Hypoxia Inducible Factor-1α (HIF-1α) and Worse Clinical Outcome in Human Colorectal Cancer

Background

Thymosin β₄ is a multi-functional hormone-like polypeptide, being involved in cell migration, angiogenesis, and tumor metastasis. This study was undertaken to clarify the clinicopathologic implications of thymosin β₄ expression in human colorectal cancers (CRCs).

Methods

We investigated tissue sections from 143 patients with CRC by immunohistochemistry. In addition, we evaluated the expression patterns and the clinico-pathological significance of thymosin β₄ expression in association with hypoxia inducible factor-1α (HIF-1α) expression in the CRC series.

Results

High expression of thymosin β₄ was significantly correlated with lymphovascular invasion, invasion depth, regional lymph node metastasis, distant metastasis, and TNM stage. Patients with high expression of thymosin β₄ showed poor recurrence-free survival (p = .001) and poor overall survival (p = .005) on multivariate analysis. We also found that thymosin β₄ and HIF-1α were overexpressed and that thymosin β₄ expression increased in parallel with HIF-1α expression in CRC.

Conclusions

A high expression level of thymosin β₄ indicates poor clinical outcomes and may be a useful prognostic factor in CRC. Thymosin β₄ is functionally related with HIF-1α and may be a potentially valuable biomarker and possible therapeutic target for CRC.

MALDI-imaging reveals thymosin beta-4 as an independent prognostic marker for colorectal cancer

DNA aneuploidy has been identified as a prognostic factor for epithelial malignancies. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is a powerful tool for direct analysis of multiple proteins in tissue sections while maintaining the cellular and molecular integrity. We compared diploid and aneuploid colon cancer tissues against normal mucosa of the colon by means of IMS.

DNA image cytometry determined the ploidy status of tissue samples that were subsequently subjected to MALDI-IMS. After obtaining protein profiles through direct analysis of tissue sections, a discovery and independent validation set were used to predict ploidy status by applying proteomic classification algorithms [Supervised Neural Network (SNN) and Receiver Operating Characteristic (ROC)]. Five peaks (m/z 2,395 and 4,977 for diploid vs. aneuploid comparison as well as m/z 3,376, 6,663, and 8,581 for normal mucosa vs. carcinoma comparison) were significant in both SNN and ROC analysis. Among these, m/z 4,977 was identified as thymosin beta 4 (Tβ-4). Tβ-4 was subsequently validated in clinical samples using a tissue microarray to predict overall survival in colon cancer patients.

Thymosin Beta 4 Is a Potential Regulator of Hepatic Stellate Cells

Liver fibrosis, a major characteristic of chronic liver disease, is inappropriate tissue remodeling caused by prolonged parenchymal cell injury and inflammation. During liver injury, hepatic stellate cells (HSCs) undergo transdifferentiation from quiescent HSCs into activated HSCs, which promote the deposition of extracellular matrix proteins, leading to liver fibrosis. Thymosin beta 4 (Tβ4), a major actin-sequestering protein, is the most abundant member of the highly conserved β-thymosin family and controls cell morphogenesis and motility by regulating the dynamics of the actin cytoskeleton. Tβ4 is known to be involved in various cellular responses, including antiinflammation, wound healing, angiogenesis, and cancer progression. Emerging evidence suggests that Tβ4 is expressed in the liver; however, its biological roles are poorly understood. Herein, we introduce liver fibrogenesis and recent findings regarding the function of Tβ4 in various tissues and discuss the potential role of Tβ4 in liver fibrosis with a special focus on the effects of exogenous and endogenous Tβ4. Recent studies have revealed that activated HSCs express Tβ4 in vivo and in vitro. Treatment with the exogenous Tβ4 peptide inhibits the proliferation and migration of activated HSCs and reduces liver fibrosis, indicating it has an antifibrotic action. Meanwhile, the endogenously expressed Tβ4 in activated HSCs is shown to promote HSCs activation. Although the role of Tβ4 has not been elucidated, it is apparent that Tβ4 is associated with HSC activation. Therefore, understanding the potential roles and regulatory mechanisms of Tβ4 in liver fibrosis may provide a novel treatment for patients.

Thymosin β4 Promotes Dermal Healing

No agent has been identified that significantly accelerates the repair of chronic dermal wounds in humans. Thymosin beta 4 (Tβ4) is a small, abundant, naturally occurring regenerative protein that is found in body fluids and inside cells. It was found to have angiogenic and antiinflammatory activity and to be high in platelets that aggregate at the wound site. Thus we used Tβ4 initially in dermal healing. It has since been shown to have many activities important in tissue protection, repair, and regeneration. Tβ4 increases the rate of dermal healing in various preclinical animal models, including diabetic and aged animals, and is active for burns as well. Tβ4 also accelerated the rate of repair in phase 2 trials with patients having pressure ulcers, stasis ulcers, and epidermolysis bullosa wounds. It is safe and well tolerated and will likely have additional uses in the skin and in injured organs for tissue repair and regeneration.

A differential screen for putative targets of the bHLH transcription factor Hand1 in cardiac morphogenesis

The bHLH transcription factor, Hand1 has been implicated in cardiac looping in the mouse, however its function in the developing heart remains unknown. To investigate the mechanism(s) through which Hand1 might function, we screened for potential downstream target genes using representational difference analysis. Thymosin beta4 was found to be down-regulated whereas cystatin C and alphaCA were up-regulated in Hand1-null embryoid bodies. Whole-mount in situ hybridisation on wild type embryos (E8.0-E10.5) and Hand1 homozygous-mutant embryos (E8.0) confirmed co-expression of the putative targets with Hand1 in the heart and their aberrant expression in a Hand1-null background.

ATF4-dependent induction of heme oxygenase 1 prevents anoikis and promotes metastasis

The integrated stress response (ISR) is a critical mediator of cancer cell survival, and targeting the ISR inhibits tumor progression. Here, we have shown that activating transcription factor 4 (ATF4), a master transcriptional effector of the ISR, protects transformed cells against anoikis - a specialized form of apoptosis - following matrix detachment and also contributes to tumor metastatic properties. Upon loss of attachment, ATF4 activated a coordinated program of cytoprotective autophagy and antioxidant responses, including induced expression of the major antioxidant enzyme heme oxygenase 1 (HO-1). HO-1 upregulation was the result of simultaneous activation of ATF4 and the transcription factor NRF2, which converged on the HO1 promoter. Increased levels of HO-1 ameliorated oxidative stress and cell death. ATF4-deficient human fibrosarcoma cells were unable to colonize the lungs in a murine model, and reconstitution of ATF4 or HO-1 expression in ATF4-deficient cells blocked anoikis and rescued tumor lung colonization. HO-1 expression was higher in human primary and metastatic tumors compared with noncancerous tissue. Moreover, HO-1 expression correlated with reduced overall survival of patients with lung adenocarcinoma and glioblastoma. These results establish HO-1 as a mediator of ATF4-dependent anoikis resistance and tumor metastasis and suggest ATF4 and HO-1 as potential targets for therapeutic intervention in solid tumors.

Potential role of thymosin Beta 4 in liver fibrosis

Liver fibrosis, the main characteristic of chronic liver diseases, is strongly associated with the activation of hepatic stellate cells (HSCs), which are responsible for extracellular matrix production. As such, investigating the effective regulators controlling HSC activation provides important clues for developing therapeutics to inhibit liver fibrosis. Thymosin beta 4 (Tβ4), a major actin-sequestering protein, is known to be involved in various cellular responses. A growing body of evidence suggests that Tβ4 has a potential role in the pathogenesis of liver fibrosis and that it is especially associated with the activation of HSCs. However, it remains unclear whether Tβ4 promotes or suppresses the activation of HSCs. Herein, we review the potential role of Tβ4 in liver fibrosis by describing the effects of exogenous and endogenous Tβ4, and we discuss the possible signaling pathway regulated by Tβ4. Exogenous Tβ4 reduces liver fibrosis by inhibiting the proliferation and migration of HSCs. Tβ4 is expressed endogenously in the activated HSCs, but this endogenous Tβ4 displays opposite effects in HSC activation, either as an activator or an inhibitor. Although the role of Tβ4 has not been established, it is apparent that Tβ4 influences HSC activation, suggesting that Tβ4 is a potential therapeutic target for treating liver diseases.

Thymosin β4 promotes hepatoblastoma metastasis via the induction of epithelial-mesenchymal transition

Hepatoblastoma (HB) is the most common malignant hepatic tumor in children and complete surgical resection offers the highest possibility for cure in this disease. Tumor metastasis is the principle obstacle to the development of efficient treatments for patients with HB. The present study aimed to measure the expression levels of thymosin β4 (Tβ4) in liver samples from patients with HB and to investigate the involvement of Tβ4 in HB metastasis. The expression of Tβ4 was significantly higher in liver samples from patients with metastatic HB and in the HepG2 metastatic HB cell line, compared with that in adjacent healthy liver samples and in the L02 healthy hepatic cell line. By contrast, the expression levels of epithelial-cadherin (E-cadherin) and cytosolic accumulation of β-catenin, the two most prominent markers involved in epithelial-mesenchymal transition (EMT), were reduced in liver specimens from patients with metastatic HB compared with that of healthy adjacent control tissue. HepG2 cells were transfected with small interfering-RNA in order to downregulate Tβ4 gene expression. This resulted in a reduced cell migratory capacity compared with control cells. Tβ4 gene expression knockdown significantly inhibited transforming growth factor β1-mediated-EMT in vitro by upregulating the expression of E-cadherin. The results of the present study suggested that Tβ4 may promote HB metastasis via the induction of EMT, and that Tβ4 may therefore be a target for the development of novel treatments for patients with HB.

Inflammation-related carcinogenesis: current findings in epidemiological trends, causes and mechanisms

Inflammation is a definite cancer-causing factor as revealed by cumulative basic, clinical and epidemiological studies. It is mostly induced by infectious agents. For instance, infection with papillomaviruses associates with anogenital cancers, especially cervical cancers; Helicobacter pylori infection of the stomach tends to increase the risk of stomach cancer; chronic hepatitis B & C viruses and fluke infections of the liver increase liver cancers; autoimmune diseases, e.g., inflammatory bowel diseases, associate with development of colorectal cancer, and aerial irritants (foreign bodies) such as asbestos or fine particulate matter (PM2.5) in outdoor air increase malignant pleural mesotheliomas or lung cancers. These are typical examples of inflammation-related carcinogenesis. It is apparent that the pathogens to induce inflammatory reactions in specific organs are not related to each other. However, the underlying pathogenesis in common is to induce and/or sustain inflammation. In this article, I would like to review the up-to-date findings of epidemiological trends, causes and mechanisms of inflammation-related carcinogenesis.

A novel predictive equation for potential diagnosis of cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common-primary liver cancer. The difficulties in diagnosis limit successful treatment of CCA. At present, histological investigation is the standard diagnosis for CCA. However, there are some poor-defined tumor tissues which cannot be definitively diagnosed by general histopathology. As molecular signatures can define molecular phenotypes related to diagnosis, prognosis, or treatment outcome, and CCA is the second most common cancer found after hepatocellularcarcinoma (HCC), the aim of this study was to develop a predictive model which differentiates CCA from HCC and normal liver tissues. An in-house PCR array containing 176 putative CCA marker genes was tested with the training set tissues of 20 CCA and 10 HCC cases. The molecular signature of CCA revealed the prominent expression of genes involved in cell adhesion and cell movement, whereas HCC showed elevated expression of genes related to cell proliferation/differentiation and metabolisms. A total of 69 genes differentially expressed in CCA and HCC were optimized statistically to formulate a diagnostic equation which distinguished CCA cases from HCC cases. Finally, a four-gene diagnostic equation (CLDN4, HOXB7, TMSB4 and TTR) was formulated and then successfully validated using real-time PCR in an independent testing set of 68 CCA samples and 77 non-CCA controls. Discrimination analysis showed that a combination of these genes could be used as a diagnostic marker for CCA with better diagnostic parameters with high sensitivity and specificity than using a single gene marker or the usual serum markers (CA19-9 and CEA). This new combination marker may help physicians to identify CCA in liver tissues when the histopathology is uncertain.

Over-expression of thymosin β4 in granulomatous lung tissue with active pulmonary tuberculosis

Recent studies have shown that thymosin β4 (Tβ4) stimulates angiogenesis by inducing vascular endothelial growth factor (VEGF) expression and stabilizing hypoxia inducible factor-1α (HIF-1α) protein. Pulmonary tuberculosis (TB), a type of granulomatous disease, is accompanied by intense angiogenesis and VEGF levels have been reported to be elevated in serum or tissue inflamed by pulmonary tuberculosis. We investigated the expression of Tβ4 in granulomatous lung tissues at various stages of active pulmonary tuberculosis, and we also examined the expression patterns of VEGF and HIF-1α to compare their Tβ4 expression patterns in patients' tissues and in the tissue microarray of TB patients. Tβ4 was highly expressed in both granulomas and surrounding lymphocytes in nascent granulomatous lung tissue, but was expressed only surrounding tissues of necrotic or caseous necrotic regions. The expression pattern of HIF-1α was similar to that of Tβ4. VEGF was expressed in both granulomas and blood vessels surrounding granulomas. The expression pattern of VEGF co-localized with CD31 (platelet endothelial cell adhesion molecule, PECAM-1), a blood endothelial cell marker, and partially co-localized with Tβ4. However, the expression of Tβ4 did not co-localize with alveolar macrophages. Stained alveolar macrophages were present surrounding regions of granuloma highly expressing Tβ4. We also analyzed mRNA expression in the sputum of 10 normal and 19 pulmonary TB patients. Expression of Tβ4 was significantly higher in patients with pulmonary tuberculosis than in normal controls. These data suggest that Tβ4 is highly expressed in granulomatous lung tissue with active pulmonary TB and is associated with HIF-1α- and VEGF-mediated inflammation and angiogenesis. Furthermore, the expression of Tβ4 in the sputum of pulmonary tuberculosis patients can be used as a potential marker for diagnosis.

Verifiable hypotheses for thymosin β4-dependent and -independent angiogenic induction of Trichinella spiralis-triggered nurse cell formation

Trichinella spiralis has been reported to induce angiogenesis for nutrient supply and waste disposal by the induction of the angiogenic molecule vascular endothelial cell growth factor (VEGF) during nurse cell formation. However, the action mechanism to induce VEGF in nurse cells by T. spiralis is not known. Hypoxia in nurse cells was suggested as a possible mechanism; however, the presence of hypoxic conditions in infected muscle or nurse cells and whether hypoxia indeed induces the expression of VEGF and subsequent angiogenesis in the infected muscle are both a matter of debate. Our recent studies have shown that thymosin β4, a potent VEGF inducing protein, is expressed in the very early stages of T. spiralis muscle infection suggesting the induction of VEGF in early stage nurse cells. Nevertheless, we now show that hypoxic conditions were not detected in any nurse cell stage but were detected only in the accumulated inflammatory cells. These studies propose that induction of angiogenesis by VEGF in T. spiralis-infected nurse cells was mediated by thymosin β4 and is unrelated to hypoxic conditions.

Cardioprotection by systemic dosing of thymosin beta four following ischemic myocardial injury

Thymosin beta 4 (Tβ4) was previously shown to reduce infarct size and improve contractile performance in chronic myocardial ischemic injury via two phases of action: an acute phase, just after injury, when Tβ4 preserves ischemic myocardium via antiapoptotic or anti-inflammatory mechanisms; and a chronic phase, when Tβ4 activates the growth of vascular or cardiac progenitor cells. In order to differentiate between the effects of Tβ4 during the acute and during the chronic phases, and also in order to obtain detailed hemodynamic and biomarker data on the effects of Tβ4 treatment suitable for use in clinical studies, we tested Tβ4 in a rat model of chronic myocardial ischemia using two dosing regimens: short term dosing (Tβ4 administered only during the first 3 days following injury), and long term dosing (Tβ4 administered during the first 3 days following injury and also every third day until the end of the study). Tβ4 administered throughout the study reduced infarct size and resulted in significant improvements in hemodynamic performance; however, chamber volumes and ejection fractions were not significantly improved. Tβ4 administered only during the first 3 days following injury tended to reduce infarct size, chamber volumes and improve hemodynamic performance. Plasma biomarkers of myocyte injury were significantly reduced by Tβ4 treatment during the acute injury period, and plasma ANP levels were significantly reduced in both dosing groups. Surprisingly, neither acute nor chronic Tβ4 treatment significantly increased blood vessel density in peri-infarct regions. These results suggest the following: repeated dosing may be required to achieve clinically measureable improvements in cardiac function post-myocardial infarction (MI); improvement in cardiac function may be observed in the absence of a high degree of angiogenesis; and that plasma biomarkers of cardiac function and myocardial injury are sensitive pharmacodynamic biomarkers of the effects of Tβ4.

Proteomic signatures of acquired letrozole resistance in breast cancer: suppressed estrogen signaling and increased cell motility and invasiveness

Aromatase inhibitors, such as letrozole, have become the first-line treatment for postmenopausal women with estrogen-dependent breast cancer. However, acquired resistance remains a major clinical obstacle. Previous studies demonstrated constitutive activation of the MAPK signaling, overexpression of HER2, and down-regulation of aromatase and ERα in letrozole-resistant breast cancer cells. Given the complex signaling network involved in letrozole-refractory breast cancer and the lack of effective treatment for hormone resistance, further investigation of aromatase inhibitor resistance by a novel systems biology approach may reveal previously unconsidered molecular changes that could be utilized as therapeutic targets. This study was undertaken to characterize for the first time global proteomic alterations occurring in a letrozole-resistant cell line. A quantitative proteomic analysis of the whole cell lysates of LTLT-Ca (resistant) versus AC-1 cells (sensitive) was performed to identify significant protein expression changes. A total of 1743 proteins were identified and quantified, of which 411 were significantly up-regulated and 452 significantly down-regulated (p < 0.05, fold change > 1.20). Bioinformatics analysis revealed that acquired letrozole resistance is associated with a hormone-independent, more aggressive phenotype. LTLT-Ca cells exhibited 84% and 138% increase in migration and invasion compared with the control cells. The ROCK inhibitor partially abrogated the enhanced migration and invasion of the letrozole-resistant cells. Flow cytometric analyses also demonstrated an increase in vimentin and twist expression in letrozole-resistance cells, suggesting an onset of epithelial to mesenchymal transition (EMT). Moreover, targeted gene expression arrays confirmed a 28-fold and sixfold up-regulation of EGFR and HER2, respectively, whereas ERα and pS2 were dramatically reduced by 28-fold and 1100-fold, respectively. Taken together, our study revealed global proteomic signatures of a letrozole-resistant cell line associated with hormone independence, enhanced cell motility, EMT and the potential values of several altered proteins as novel prognostic markers or therapeutic targets for letrozole resistant breast cancer.

Nanog suppresses cell migration by downregulating thymosin β4 and Rnd3

Nanog, Sox2, and Oct4 are key transcription factors critical for the pluripotency and self-renewal of embryonic stem (ES) cells. Their downregulations lead to differentiation, accompanied with changes in cell motility. Whether these factors impact cell motility directly, however, is not clear. Here we addressed this question by initially assessing their effect in non-stem cells. We found that the ectopic expression of Nanog, Sox2, or Oct4 markedly inhibited ECV304 cell migration. Detailed examinations revealed that Nanog induced disorganizations of the actin cytoskeleton and peripheral localizations of focal adhesions. These effects required its DNA-binding domain and are thus transcription dependent. Furthermore, thymosin β4 and Rnd3 were identified as its downstream targets. Their depletions in ECV304 cells by RNAi phenocopied the ectopic expression of Nanog in both cell motility and actin organization, whereas their ectopic expressions rescued the migration defect of Nanog overexpression. Both proteins were upregulated during mouse ES cell differentiation. Their levels in the pluripotent mouse P19 cells also increased upon Nanog ablation, coincident with an increase in cell motility. Moreover, persistent expression of Nanog in zebrafish embryos suppressed gastrulation and cell migration. These results indeed suggest a dual role of certain transcription factors in the orchestration of differentiation and motility.

Thymosin β4 stabilizes hypoxia-inducible factor-1α protein in an oxygen-independent manner

The small actin-binding protein thymosin β4 (Tβ4) is understood to stimulate angiogenesis. Previously, we reported that Tβ4 induces angiogenesis by increasing vascular endothelial growth factor (VEGF) expression, but the mechanism underlying how Tβ4 upregulates VEGF expression remain unknown. To identify the mechanism of VEGF induction by Tβ4, we measured VEGF promoter activity and analyzed the effect of Tβ4 on VEGF RNA stability. The Tβ4 peptide had no effect on either VEGF promoter activity or VEGF RNA stability. We focused on the possibility that Tβ4 may indirectly induce VEGF expression via hypoxia-inducible factor (HIF)-1α. We determined that Tβ4 increased the stability of HIF-1α protein under normoxic conditions. These data suggest that Tβ4 indirectly induces VEGF expression by increasing the protein stability of HIF-1α in an oxygen-independent manner.

Effects of maternal separation and methamphetamine exposure on protein expression in the nucleus accumbens shell and core

Early life adversity has been suggested to predispose an individual to later drug abuse. The core and shell sub-regions of the nucleus accumbens are differentially affected by both stressors and methamphetamine. This study aimed to characterize and quantify methamphetamine-induced protein expression in the shell and core of the nucleus accumbens in animals exposed to maternal separation during early development. Isobaric tagging (iTRAQ) which enables simultaneous identification and quantification of peptides with tandem mass spectrometry (MS/MS) was used. We found that maternal separation altered more proteins involved in structure and redox regulation in the shell than in the core of the nucleus accumbens, and that maternal separation and methamphetamine had differential effects on signaling proteins in the shell and core. Compared to maternal separation or methamphetamine alone, the maternal separation/methamphetamine combination altered more proteins involved in energy metabolism, redox regulatory processes and neurotrophic proteins. Methamphetamine treatment of rats subjected to maternal separation caused a reduction of cytoskeletal proteins in the shell and altered cytoskeletal, signaling, energy metabolism and redox proteins in the core. Comparison of maternal separation/methamphetamine to methamphetamine alone resulted in decreased cytoskeletal proteins in both the shell and core and increased neurotrophic proteins in the core. This study confirms that both early life stress and methamphetamine differentially affect the shell and core of the nucleus accumbens and demonstrates that the combination of early life adversity and later methamphetamine use results in more proteins being affected in the nucleus accumbens than either treatment alone.

Association between serum thymosin β4 levels of rheumatoid arthritis patients and disease activity and response to therapy

The aim of this study was to evaluate whether thymosin β4 (Tβ4) levels are increased in the serum of rheumatoid arthritis (RA) patients, and if this increase is associated with RA disease activity and resistance to treatment. Blood samples from 40 patients with RA were collected at baseline and 6 months after starting treatment with disease-modifying antirheumatic drugs (DMARD) and/or tumor necrosis factor (TNF)-α blocker. Serum levels of Tβ4 were measured by ELISA. Tβ4 levels (mean ± standard deviation) in RA patients were significantly (approximately tenfold) higher than in healthy controls (577.4 ± 67.92 vs. 56.61 ± 5.72 ng/mL). Serum Tβ4 levels in patients with severe disease activity before therapy were slightly higher than in patients with moderate disease activity (662.4 ± 491.5 vs. 462.5 ± 305.3 ng/ml, P > 0.05). Tβ4 levels were significantly associated with disease activity according to the 28-joint Disease Activity Score. The mean Tβ4 level at baseline in the DMARD treatment group was significantly lower than in the DMARD + TNF-α blocker treatment group. Tβ4 levels were increased in the serum of patients with RA and were positively associated with disease activity. Levels of Tβ4 may also be relevant in determining or predicting resistance to RA treatment. Further studies are necessary to determine if Tβ4 is an appropriate therapeutic target for controlling inflammation associated with RA.

Thymosin β4 is a novel potential prognostic marker in gastrointestinal stromal tumors

Thymosin beta-4 (Tβ(4)) is a major actin-sequestering molecule that contributes to cell growth, differentiation, motility, survival, mitosis and angiogenesis. It is overexpressed in certain type of carcinoma and fibrosarcoma cell lines and is associated with metastatic potential. The aim of this study was to investigate the relationship between Tβ(4) expression and clinicopathologic features and VEGF status in gastrointestinal stromal tumors (GISTs). Retrospectively, 60 GISTs were re-examined and immunohistochemistry for Tβ(4) and VEGF was performed. Increased expression of Tβ(4) and VEGF was observed in 26 (43.3%) and in 19 (31.6%) of the tumors, respectively. Tβ(4) expression was positively correlated with VEGF expression (p < 0.01). Tβ(4) and VEGF expression were significantly associated with tumor size (p = 0.00 and p = 0.02, respectively) and high mitosis (p = 0.03 and p = 0.00, respectively). Although Tβ(4) expression was positively associated with pleomorphism (p = 0.01), VEGF expression was positively associated with necrosis (p = 0.03). Tβ(4) expression was related with local recurrence and/or metastasis (p = 0.03), but VEGF expression was not (p = 0.12). We firstly demonstrate the presence of Tβ(4) protein in GISTs. Our study reveals that increased expression of Tβ(4) could be considered as an indicator of aggressive behavior of tumor.

Thymosin β 4 in colorectal cancer is localized predominantly at the invasion front in tumor cells undergoing epithelial mesenchymal transition

OBJECTIVE

Thymosin β 4 (Tβ(4)) is a ubiquitous peptide that plays pivotal roles in the cytoskeletal system and in cell differentiation during embryogenesis. Recently, a role for Tβ(4) has been proposed in experimental and human carcinogenesis. This study was aimed at evaluating the correlation between Tβ(4) immunoractivity and colorectal cancer, with particular attemption to tumor cells undergoing epithelial-mesenchymal transition.

METHODS AND RESULTS

86 intestinal biopsies were retrospectively analyzed including 76 colorectal adenocarcinomas with evident features of epithelial-mesenchymal transition, and 10 samples of normal colorectal mucosa. Paraffin sections were immunostained for Tβ(4) and for E-cadherin. Total RNA was isolated from frozen specimens obtained, at surgery, from the normal colon mucosa, the deeper regions and the superficial tumor regions in four cases of colon cancer. Tβ(4) immunoreactivity was detected in the vast majority (59/76) of colon carcinomas, showing a patchy distribution, with well differentiated areas significantly more reactive than the less differentiated tumor zones. We also noted a zonal pattern in the majority of tumors, characterized by a progressive increase in immunostaining for Tβ(4) from the superficial toward the deepest tumor regions. The strongest expression for Tβ(4) was frequently detected in invading tumor cells with features of epithelial-mesenchymal transition. The increase in reactivity for Tβ(4) matched with a progressive decrease in E-cadherin expression in invading cancer cells. At mRNA level, the differences in Tβ(4) expression between the surrounding colon mucosa and the tumors samples were not significant.

CONCLUSIONS

Our data show that Tβ(4) is expressed in the majority of colon cancers, with preferential immunoreactivity in deep tumor regions. The preferential expression of the peptide and the increase in intensity of the immunostaining at the invasion front suggests a possible link between the peptide and the process of epithelial mesenchymal transition, suggesting a role for Tβ(4) in colorectal cancer invasion and metastasis.

Increased levels of thymosin β4 in synovial fluid of patients with rheumatoid arthritis: association of thymosin β4 with other factors that are involved in inflammation and bone erosion in joints

AIM

Thymosin (Tβ4) may have various biological effects that are relevant to the pathogenesis of rheumatoid arthritis (RA). This study was performed to gain insight into the relevance of Tβ4 in the pathogenesis of inflammatory arthritis.

METHOD

The level of Tβ4 in synovial fluid from patients with osteoarthritis (OA) or RA was measured by enzyme-linked immunosorbent assay. An association between Tβ4 and matrix metalloproteinase (MMP)-1 and MMP-13 (collagenases), MMP-2 and MMP-9 (gelatinases), MMP-7, adiponectin, lactoferrin, vascular endothelial growth factor (VEGF), urokinase-type plasminogen activator (uPA), interleukin (IL)-6, IL-8 and prostaglandin E2 (PGE(2) ) in synovial joint fluids from OA and RA patients were investigated.

RESULTS

The level of Tβ4 in the synovial joint fluid of patients with OA and RA was (mean ± SD) 145 ± 88 and 1359 ± 1685 ng/mL, respectively. The level of Tβ4 in the synovial joint fluid of RA patients was significantly associated with the levels of MMP-9, MMP-13, VEGF, uPA, IL-6 and IL-8, but not with MMP-1, MMP-2, MMP-7, adiponectin and lactoferrin. In contrast, the level of Tβ4 in the synovial joint fluid of patients with OA was not associated with any of these molecules.

CONCLUSIONS

The results suggest that Tβ4 may play an important role in bone degradation and inflammation in RA but not OA, although nothing is known about the molecular mechanisms mediating Tβ4 in arthritic joints. The role of Tβ4 in arthritis should be studied to understand its relevance to the pathogenic processes in arthritis.

Lung cancer diagnosis from proteomic analysis of preinvasive lesions

Early detection may help improve survival from lung cancer. In this study, our goal was to derive and validate a signature from the proteomic analysis of bronchial lesions that could predict the diagnosis of lung cancer. Using previously published studies of bronchial tissues, we selected a signature of nine matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) mass-to-charge ratio features to build a prediction model diagnostic of lung cancer. The model was based on MALDI MS signal intensity (MALDI score) from bronchial tissue specimens from our 2005 published cohort of 51 patients. The performance of the prediction model in identifying lung cancer was tested in an independent cohort of bronchial specimens from 60 patients. The probability of having lung cancer based on the proteomic analysis of the bronchial specimens was characterized by an area under the receiver operating characteristic curve of 0.77 (95% CI 0.66-0.88) in this validation cohort. Eight of the nine features were identified and validated by Western blotting and immunohistochemistry. These results show that proteomic analysis of endobronchial lesions may facilitate the diagnosis of lung cancer and the monitoring of high-risk individuals for lung cancer in surveillance and chemoprevention trials.

In silico analysis of combinatorial microRNA activity reveals target genes and pathways associated with breast cancer metastasis

This is an open access article. Unrestricted non-commercial use is permitted provided the original work is properly cited.

Aberrant microRNA activity has been reported in many diseases, and studies often find numerous microRNAs concurrently dysregulated. Most target genes have binding sites for multiple microRNAs, and mounting evidence indicates that it is important to consider their combinatorial effect on target gene repression. A recent study associated the coincident loss of expression of six microRNAs with metastatic potential in breast cancer. Here, we used a new computational method, miR-AT!, to investigate combinatorial activity among this group of microRNAs. We found that the set of transcripts having multiple target sites for these microRNAs was significantly enriched with genes involved in cellular processes commonly perturbed in metastatic tumors: cell cycle regulation, cytoskeleton organization, and cell adhesion. Network analysis revealed numerous target genes upstream of cyclin D1 and c-Myc, indicating that the collective loss of the six microRNAs may have a focal effect on these two key regulatory nodes. A number of genes previously implicated in cancer metastasis are among the predicted combinatorial targets, including TGFB1, ARPC3, and RANKL. In summary, our analysis reveals extensive combinatorial interactions that have notable implications for their potential role in breast cancer metastasis and in therapeutic development.

Microenvironment alters epigenetic and gene expression profiles in Swarm rat chondrosarcoma tumors

BACKGROUND

Chondrosarcomas are malignant cartilage tumors that do not respond to traditional chemotherapy or radiation. The 5-year survival rate of histologic grade III chondrosarcoma is less than 30%. An animal model of chondrosarcoma has been established--namely, the Swarm Rat Chondrosarcoma (SRC)--and shown to resemble the human disease. Previous studies with this model revealed that tumor microenvironment could significantly influence chondrosarcoma malignancy.

METHODS

To examine the effect of the microenvironment, SRC tumors were initiated at different transplantation sites. Pyrosequencing assays were utilized to assess the DNA methylation of the tumors, and SAGE libraries were constructed and sequenced to determine the gene expression profiles of the tumors. Based on the gene expression analysis, subsequent functional assays were designed to determine the relevancy of the specific genes in the development and progression of the SRC.

RESULTS

The site of transplantation had a significant impact on the epigenetic and gene expression profiles of SRC tumors. Our analyses revealed that SRC tumors were hypomethylated compared to control tissue, and that tumors at each transplantation site had a unique expression profile. Subsequent functional analysis of differentially expressed genes, albeit preliminary, provided some insight into the role that thymosin-β4, c-fos, and CTGF may play in chondrosarcoma development and progression.

CONCLUSION

This report describes the first global molecular characterization of the SRC model, and it demonstrates that the tumor microenvironment can induce epigenetic alterations and changes in gene expression in the SRC tumors. We documented changes in gene expression that accompany changes in tumor phenotype, and these gene expression changes provide insight into the pathways that may play a role in the development and progression of chondrosarcoma. Furthermore, specific functional analysis indicates that thymosin-β4 may have a role in chondrosarcoma metastasis.

Thymosin β4 induces the expression of vascular endothelial growth factor (VEGF) in a hypoxia-inducible factor (HIF)-1α-dependent manner

Thymosin β4 has multi-functional roles in cell physiology, but little is known about its mechanism(s) of action. We previously reported that thymosin β4 stimulated angiogenesis through the induction of vascular endothelial growth factor (VEGF). To identify the mechanism of VEGF induction by thymosin β4, we have used a luciferase assay system with VEGF in the 5' promoter region. We also analyzed the effect of thymosin β4 on VEGF mRNA stability and on the expression and stability of hypoxia-inducible factor (HIF)-1α. We found that thymosin β4 induces VEGF expression by an increase in the stability of HIF-1α protein. Analysis of the expression patterns of thymosin β4 and HIF-1α in colon cancer tissue microarray showed that thymosin β4 and HIF-1α co-localized in these biopsies. These data show that thymosin β4 induces the expression of VEGF indirectly by increasing the protein stability of HIF-1α.

Thymosin beta4 in multiple myeloma: friend or foe

Multiple myeloma (MM) is a malignancy characterized by the accumulation of monoclonal plasma cells in the bone marrow (BM). Because of the known involvement of thymosin beta4 (Tbeta4) in metastasis of tumor cells, we examined the expression and role of Tbeta4 in MM disease. In a large patient population, we demonstrated that Tbeta4 expression was significantly lower in myeloma cells compared to normal plasma cells and that patients with a high Tbeta4 expression had a longer event free and overall survival. The decreased Tbeta4 expression was also found in the murine 5TMM model. To study its function, we overexpressed the Tbeta4 gene in 5T33MMvt cells by lentiviral transduction. These cells demonstrated a decreased proliferative capability and an increased sensitivity to apoptosis. Mice injected with Tbeta4-overexpressing cells showed a prolonged survival compared to mice injected with controls. In contrast to its role in solid tumors, we found a decreased expression in myeloma cells compared to their normal counterpart and studies with overexpression of the Tbeta4 gene indicated a tumor suppressive function of Tbeta4 in myeloma development.

Animal studies with thymosin beta, a multifunctional tissue repair and regeneration peptide

Studies in various animal models of disease and repair with thymosin beta(4) (Tbeta(4)), the major actin-sequestering molecule in mammalian cells, have provided the scientific foundation for the ongoing dermal, corneal, and cardiac wound repair multicenter clinical trials. Tbeta(4) has of multiple biological activities, which include down-regulation of inflammatory chemokines and cytokines, and promotion of cell migration, blood vessel formation, cell survival, and stem cell maturation. All of these activities contribute to the multiple wound healing properties that have been observed in animal studies. This paper reviews and discusses the topical and systemic uses of Tbeta(4) in various animal models that demonstrate its potential for clinical use.

Overexpression of the natural tetrapeptide acetyl-N-ser-asp-lys-pro derived from thymosin beta4 in neoplastic diseases

The natural tetrapeptide acetyl-ser-asp-lys-pro (AcSDKP) is formed in vivo by enzymatic cleavage of the N terminus of thymosin beta4 by prolyl oligopeptidase (POP). Recently, AcSDKP was shown to promote angiogenesis. Because of the critical role of neovascularization in cancer development, the levels of AcSDKP and POP activity in a number of different malignant tissues were investigated. Our studies revealed that AcSDKP levels were markedly elevated in neoplastic diseases including hematologic malignancies and solid neoplasms. Consistent with this finding, the enhanced activity of POP was also detected in all analyzed specimens of cancer tissues. Both these novel findings are in concert with the previously reported overexpression of thymosin beta4 in a large variety of malignant tumors and with its potential role in cancerogenesis. The physiological relevance of these findings awaits further studies; however, our first results strongly suggest a key role for AcSDKP in the pathogenesis of cancer.