The role of translationally controlled tumor protein in tumor growth and metastasis of colon adenocarcinoma cells

Prognostic value of translationally controlled tumor protein in colon cancer

The translationally controlled tumor protein (TCTP) is a highly conserved protein involved in a variety of normal cell functions and disease processes. Preclinical studies revealed that TCTP has anti-apoptotic properties, promotes cell growth and division and is involved in cancer progression by promoting invasion and metastasis. The present study explored the potential value of TCTP as a prognostic marker in colon cancer. A retrospective analysis of 74 patients with colon cancer was performed. Using immunohistochemistry, TCTP levels in the primary tumor were assessed semi-quantitatively by the calculation of cytoplasmic and nuclear H-score. Cytoplasmic TCTP levels in the primary tumor had no statistically significant association with disease-free survival (DFS), progression-free survival (PFS) and overall survival (OS) in the present patient population. Patients whose primary tumors had a negative nuclear TCTP expression had significantly improved clinical outcomes. The PFS for the negative nuclear TCTP expression group was 7.7 months [95% confidence interval (CI), 5.8-9.5] compared with 5.5 months (95% CI, 3.2-7.8) in the group with positive nuclear expression (P=0.023, Mantel-Cox log-rank). Patients with a negative nuclear expression of TCTP had a significantly higher median OS (22.2 months; 95% CI, 16.1-28.3) compared with those with positive TCTP nuclear expression (median 13.2 months; 95% CI, 10.1-16.3; P=0.008, Mantel-Cox log-rank). In a multivariate Cox regression model, a positive nuclear TCTP H-score was an independent risk factor for worse PFS and OS. The 1-year OS rate in the group with negative nuclear TCTP expression was 86.3% compared with 56.5% in patients with positive nuclear TCTP expression (P=0.008). The present study suggested that semiquantitative H-score measurement of TCTP levels in the nuclei of tumor cells from the primary tumor is a potential prognostic marker for clinical outcomes in patients with colon cancer.

Translationally controlled tumor protein: the mediator promoting cancer invasion and migration and its potential clinical prospects

Translationally controlled tumor protein (TCTP) is a highly conserved multifunctional protein localized in the cytoplasm and nucleus of eukaryotic cells. It is secreted through exosomes and its degradation is associated with the ubiquitin-proteasome system (UPS), heat shock protein 27 (Hsp27), and chaperone-mediated autophagy (CMA). Its structure contains three α‍-helices and eleven β‍-strands, and features a helical hairpin as its hallmark. TCTP shows a remarkable similarity to the methionine-R-sulfoxide reductase B (MsrB) and mammalian suppressor of Sec4 (Mss4/Dss4) protein families, which exerts guanine nucleotide exchange factor (GEF) activity on small guanosine triphosphatase (GTPase) proteins, suggesting that some functions of TCTP may at least depend on its GEF action. Indeed, TCTP exerts GEF activity on Ras homolog enriched in brain (Rheb) to boost the growth and proliferation of Drosophila cells. TCTP also enhances the expression of cell division control protein 42 homolog (Cdc42) to promote cancer cell invasion and migration. Moreover, TCTP regulates cytoskeleton organization by interacting with actin microfilament (MF) and microtubule (MT) proteins and inducing the epithelial-mesenchymal transition (EMT) process. In essence, TCTP promotes cancer cell movement. It is usually highly expressed in cancerous tissues and thus reduces patient survival; meanwhile, drugs can target TCTP to reduce this effect. In this review, we summarize the mechanisms of TCTP in promoting cancer invasion and migration, and describe the current inhibitory strategy to target TCTP in cancerous diseases.

The Sphingosine Kinase 2 Inhibitor ABC294640 Restores the Sensitivity of BRAFV600E Mutant Colon Cancer Cells to Vemurafenib by Reducing AKT-Mediated Expression of Nucleophosmin and Translationally-Controlled Tumour Protein

Vemurafenib (PLX4032), small-molecule inhibitor of mutated BRAFV600E protein, has emerged as a potent anti-cancer agent against metastatic melanoma harboring BRAFV600E mutation. Unfortunately, the effect of PLX4032 in the treatment of metastatic BRAF mutated colorectal cancer (CRC) is less potent due to high incidence of fast-developing chemoresistance. It has been demonstrated that sphingolipids are important mediators of chemoresistance to various therapies in colon cancer. In this study, we will explore the role of major regulators of sphingolipid metabolism and signaling in the development of resistance to vemurafenib in BRAF mutant colon cancer cells. The obtained data revealed significantly increased expression levels of activated sphingosine kinases (SphK1 and SphK2) in resistant cells concomitant with increased abundance of sphingosine-1-phosphate (S1P) and its precursor sphingosine, which was accompanied by increased expression levels of the enzymes regulating the ceramide salvage pathway, namely ceramide synthases 2 and 6 and acid ceramidase, especially after the exposure to vemurafenib. Pharmacological inhibition of SphK1/SphK2 activities or modulation of ceramide metabolism by exogenous C6-ceramide enhanced the anti-proliferative effect of PLX4032 in resistant RKO cells in a synergistic manner. It is important to note that the inhibition of SphK2 by ABC294640 proved effective at restoring the sensitivity of resistant cells to vemurafenib at the largest number of combinations of sub-toxic drug concentrations with minimal cytotoxicity. Furthermore, the obtained findings revealed that enhanced anti-proliferative, anti-migratory, anti-clonogenic and pro-apoptotic effects of a combination treatment with ABC294640 and PLX4032 relative to either drug alone were accompanied by the inhibition of S1P-regulated AKT activity and concomitant abrogation of AKT-mediated cellular levels of nucleophosmin and translationally-controlled tumour protein. Collectively, our study suggests the possibility of using the combination of ABC294640 and PLX4032 as a novel therapeutic approach to combat vemurafenib resistance in BRAF mutant colon cancer, which warrants additional preclinical validation studies.

Comparative modelling unravels the structural features of eukaryotic TCTP implicated in its multifunctional properties: an in silico approach

Comparative modelling helps compare the structure and functions of a given protein, to track the path of its origin and evolution and also guide in structure-based drug discovery. Presently, this has been applied for modelling the tertiary structure of highly conserved eukaryotic TCTP (translationally controlled tumour protein) which is involved in a plethora of functions during growth and development and also acts as a biomarker for many cancers like lung, breast, and prostate cancer. The modelled TCTP structures of different organisms belonging to the eukaryotic group showed similar spatial arrangement of structural units except loops and similar patterns of root mean square deviation (RMSD), root mean square fluctuation, and radius of gyration (Rg) inspected through molecular dynamics simulations. Essential dynamics (ED) analyses revealed different domains that exhibited different motions for the assistance in its multifunctional properties. Construction of a free-energy landscape (FEL) based on Rg versus RMSD was employed to characterize the folding behaviours of structures and observe that all proteins had nearly similar conformation and topologies, indicating common thermodynamic/kinetic pathways. A physico-chemical interaction study demonstrated the helices and sheets were well stabilized with ample amounts of bonding compared to turns or loops and charged residues were more accessible to solvent molecules. Hence, the current study reveals the important structural features of TCTP that aid in diverse functions in a wide range of organisms, thus extending our knowledge of TCTP and also providing a venue for designing the potent inhibitors against it.

The permissive role of TCTP in PM2.5/NNK-induced epithelial-mesenchymal transition in lung cells

Background

Translationally controlled tumor protein (TCTP) is linked to lung cancer. However, upon lung cancer carcinogens stimulation, there were no reports on the relationship between TCTP and lung cell carcinogenic epithelial–mesenchymal transition (EMT). This study was designed to investigate the molecular mechanism of regulation of TCTP expression and its role in lung carcinogens-induced EMT.

Methods

To study the role of TCTP in lung carcinogens [particulate matter 2.5 (PM_2.5) or 4-methylnitrosamino-l-3-pyridyl-butanone (NNK)]-induced EMT, PM_2.5/NNK-treated lung epithelial and non-small cell lung cancer (NSCLC) cells were tested. Cell derived xenografts, human lung cancer samples and online survival analysis were used to confirm the results. MassArray assay, Real-time PCR and Reporter assays were performed to elucidate the mechanism of regulation of TCTP expression. All statistical analyses were performed using GraphPad Prism version 6.0 or SPSS version 20.0.

Results

Translationally controlled tumor protein and vimentin expression were up-regulated in PM_2.5/NNK-treated lung cells and orthotopic implantation tumors. TCTP expression was positively correlated with vimentin in human NSCLC samples. Patients with high expression of TCTP displayed reduced overall and disease-free survival. TCTP overexpression could increase vimentin expression and promote cell metastasis. Furthermore, PM_2.5/NNK stimulation brought a synergistic effect on EMT in TCTP-transfected cells. TCTP knockdown blocked PM_2.5/NNK carcinogenic effect. Mechanically, PM_2.5/NNK-induced TCTP expression was regulated by one microRNA, namely miR-125a-3p, but not by methylation on TCTP gene promoter. The level of TCTP was regulated by its specific microRNA during the process of PM_2.5/NNK stimulation, which in turn enhanced vimentin expression and played a permissive role in carcinogenic EMT.

Conclusions

Our results provided new insights into the mechanisms of TCTP regulatory expression in lung carcinogens-induced EMT. TCTP and miR-125a-3p might act as potential prognostic biomarkers and therapeutic targets for NSCLC.

Regulation of Autophagy Is a Novel Tumorigenesis-Related Activity of Multifunctional Translationally Controlled Tumor Protein

Translationally controlled tumor protein (TCTP) is highly conserved in eukaryotic organisms and plays multiple roles regulating cellular growth and homeostasis. Because of its anti-apoptotic activity and its role in the regulation of cancer metastasis, TCTP has become a promising target for cancer therapy. Moreover, growing evidence points to its clinical role in cancer prognosis. How TCTP regulates cellular growth in cancer has been widely studied, but how it regulates cellular homeostasis has received relatively little attention. This review discusses how TCTP is related to cancer and its potential as a target in cancer therapeutics, including its novel role in the regulation of autophagy. Regulation of autophagy is essential for cell recycling and scavenging cellular materials to sustain cell survival under the metabolic stress that cancer cells undergo during their aggressive proliferation.

Analysis of translation control tumor protein related to deltamethrin stress in Drosophila kc cells

The translation control tumor protein (TCTP) is a kind of conservative, common and important molecule, several functions (such as regulating cell cycle, apoptosis and calcium binding) have been reported. However, few academic researches for role of TCTP in insecticides stress were made so far. In this research, Drosophila kc cells treated with different doses of deltamethrin at different times, indicated that the expression of TCTP reached the highest level when the cells were treated with 20 ppm of deltamethrin at 24 h. The results showed that TCTP expression is associated with deltamethrin stress. To investigate the functional relationship between this gene and deltamethrin resistance, RNA interference (RNAi) and cell transfection were utilized. TCTP knockdown significantly reduced the level of resistance of RNAi-treated cells, and the overexpressions of TCTP in Drosophila kc cells conferred a degree of protection against deltamethrin. Flow cytometry data showed increased apoptosis rate of RNAi-treated cells and decreased apoptosis following cell transfection. These results represent the first evidence that TCTP plays an important role in the regulation of deltamethrin resistance. Therefore, this study could help us to elucidate the environmental toxicity of deltamethrin and new target genes associated with resistance.

A Potential Role for Exosomal Translationally Controlled Tumor Protein Export in Vascular Remodeling in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by increased proliferation and resistance to apoptosis of pulmonary vascular cells. Increased expression of translationally controlled tumor protein (TCTP), a prosurvival and antiapoptotic mediator, has recently been demonstrated in patients with heritable PAH; however, its role in the pathobiology of PAH remains unclear. Silencing of TCTP in blood outgrowth endothelial cells (BOECs) isolated from control subjects led to significant changes in morphology, cytoskeletal organization, increased apoptosis, and decreased directionality during migration. Because TCTP is also localized in extracellular vesicles, we isolated BOEC-derived extracellular vesicles (exosomes and microparticles) by sequential ultracentrifugation. BOECs isolated from patients harboring BMPR2 mutations released more exosomes than those derived from control subjects in proapoptotic conditions. Furthermore, TCTP expression was significantly higher in exosomes than in microparticles, indicating that TCTP is mainly exported via exosomes. Coculture assays demonstrated that exosomes transferred TCTP from ECs to pulmonary artery smooth muscle cells, suggesting a role for endothelial-derived TCTP in conferring proliferation and apoptotic resistance. In an experimental model of PAH, rats treated with monocrotaline demonstrated increased concentrations of TCTP in the lung and plasma. Consistent with this finding, we observed increased circulating TCTP levels in patients with idiopathic PAH compared with control subjects. Therefore, our data suggest an important role for TCTP in regulating the critical vascular cell phenotypes that have been implicated in the pathobiology of PAH. In addition, this research implicates TCTP as a potential biomarker for the onset and development of PAH.

microRNA-1236-3p Regulates DDP Resistance in Lung Cancer Cells

Lung cancer is a malignant tumor leading to the most cancer-related deaths worldwide. The treatment efficiency of lung cancer remains poor mainly due to chemotherapy drug resistance, including cisplatin. MicroRNAs (miRNAs) are closely related to chemotherapy resistance of tumor cells. Here, we illustrated the underlying mechanism of miR-1236-3p on the DDP resistance in lung cancer cells. In this study, we found that the expression level of miR-1236-3p was significantly decreased in lung cancer tissues and A549 cell line. In addition, the half maximal inhibitory concentration (IC50) of DDP in A549 cells was significantly lower than that in A549/DDP cells, while the expression level of miR-1236-3p was prominently down-regulated in A549/DDP cells. Combining the online tool TargetScan and a dual-luciferase reporter assay, tumor protein, translationally-controlled 1 (TPT1) was proved to be the direct target gene of miR-1236-3p. The MTT and flow cytometry assays demonstrated that up-regulation of miR-1236-3p could markedly inhibit A549/DDP cell proliferation but promote apoptosis, which could be significantly reversed by pcDNA3.1-TPT1 plasmids. Finally, we further demonstrated that miR-1235-3p could restrain the expression levels of TPT1, Pim-3, phosphate-Bcl-2-associated death promoter (p-BAD) and B-cell lymphoma-extra large (Bcl-XL) in A549/DDP cells, while the inhibition could be reversed by pcDNA3.1-TPT1 as well. In a word, our study demonstrated that miR-1236-3p could reverse DDP resistance by modulation of TPT1 gene and inhibition of Pim-3 signaling pathway in lung cancer cells.

Translationally controlled tumor protein affects colorectal cancer metastasis through the high mobility group box 1-dependent pathway

Recently, accumulating evidence from clinical and experimental researches have suggested that translationally controlled tumor protein (TCTP) and high mobility group box 1 (HMGB1) are implicated in colorectal cancer (CRC) metastasis. However, whether there is an interconnection between these two tumor-promoting proteins and how they affect CRC metastasis remain to be fully elucidated. In the present study, the expression level of TCTP in CRC tissues was assessed by immunohistochemical staining and immunoblotting, and the serum concentration of HMGB1 in patients with CRC was detected by enzyme-linked immunosorbent assay. In vitro, following the modulation of TCTP expression in colon cancer LoVo cells, the translocation behavior of HMGB1 was observed by immunofluorescence assay. Furthermore, the activity of nuclear factor-κB (NF-κB) in LoVo cells was evaluated by immunoblotting and luciferase assay, and the invasion ability of LoVo cells after different treatments was determined using cell invasion assay. In vivo, xenograft tumor model was established and the correlation of TCTP and HMGB1 expression in xenografted tumors was studied by immunohistochemical examination. The results revealed that the expression level of TCTP in CRC tissue and the serum concentration of HMGB1 in patients with CRC were significantly increased, and there was a strong positive correlation between them. In vitro experiments showed that the overexpression of TCTP on LoVo cells resulted in the release of HMGB1 from the nucleus to the cytoplasm and into the extracellular space. In addition, the overexpression of TCTP led to the activation of NF-κB in LoVo cells, and this effect was reversed by treatment with antibodies targeting HMGB1 or to its receptors Toll-like receptor 4 (TLR4) and receptor for advanced glycation end products advanced glycation end products (RAGE). Furthermore, inhibition of the HMGB1-TLR4/RAGE-NF-κB pathway significantly inhibited the TCTP-stimulated invasion of LoVo cells. In vivo experiments demonstrated that the over-expression of TCTP in nude mice promoted the development and spread of xenografted tumors, and concurrently enhanced the expression of HMGB1 in tumor tissues. Collectively, these findings suggested that TCTP promotes CRC metastasis through regulating the behaviors of HMGB1 and the downstream activation of the NF-κB signaling pathway.

Proteomic analysis reveals that pheophorbide a-mediated photodynamic treatment inhibits prostate cancer growth by hampering GDP-GTP exchange of ras-family proteins

BACKGROUND

We previously reported that pheophorbide a (PhA), excited by 630 nm light, significantly inhibited the growth of prostate cancer cells. In this study, we employed whole-cell proteomics to investigate photodynamic treatment (PDT)-related proteins.

METHODS

Two-dimensional gel electrophoresis (2-DE) coupled with tandem mass spectrometry was employed to reveal the proteins involved in PhA-mediated PDT in LNCaP and PC-3 prostate cancer cells.

RESULTS

After PhA-PDT treatment, decreased expression of translationally-controlled tumor protein (TCTP) was found in both PC-3 and LNCaP whole-cell proteomes. In contrast, human rab GDP dissociation inhibitor (GDI) in LNCaP cells and ras-related homologs GDI in PC-3 cells were up-regulated.

CONCLUSIONS

GDP-GTP exchange is an underlying target of photodynamic treatment in prostate cancer cells.

A gene signature associated with PTEN activation defines good prognosis intermediate risk prostate cancer cases

Accurate identification of intermediate risk (Gleason 3 + 4 = 7) prostate cancer patients with low risk of disease progression is an unmet challenge in treatment decision making. Here we describe a gene signature that could guide clinicians in the selection of patients with intermediate stage clinically localized prostate cancer for active surveillance. We examined six major drivers of aggressive disease - PTEN, MYC, RB1, TP53, AURKA, AR - by immunohistochemistry in a focused (N = 69) cohort predominantly consisting of intermediate risk prostate cancer. Fuzzy clustering and unsupervised hierarchical clustering were utilized to determine the correlation of gene expression and methylation values with immunohistochemical expression. From the immunohistochemistry observation, we found that intermediate risk prostate cancer cases could be classified as 'complex' (differential expression of more than one driver) or 'simple' (differential expression of only one). Focussing on the 'simple' cases, expression and methylation profiling generated signatures which correlated tightly only with differential PTEN expression and not with any of the other drivers assessed by immunohistochemistry. From this, we derived a geneset of 35 genes linked to high PTEN expression. Subsequently we determined its prognostic significance in intermediate-risk cases extracted from three publicly available clinical datasets (Total N = 215). Hence, this study shows that, by using immunohistochemistry as an upfront stratifier of intermediate risk prostate cancers, it is possible to identify through differential gene expression profiling a geneset with prognostic power across multiple cohorts. This strategy has not been used previously and the signature has the potential to impact on treatment decisions in patients for whom decision making is currently empirical at best.

Extracellular translationally controlled tumor protein promotes colorectal cancer invasion and metastasis through Cdc42/JNK/ MMP9 signaling

The translationally controlled tumor protein (TCTP) can be secreted independently of the endoplasmic reticulum/Golgi pathway and has extrinsic activities when it is characterized as the histamine releasing factor (HRF). Despite its important role in allergies and inflammation, little is known about how extracellular TCTP affects cancer progression. In this study, we found that TCTP was overexpressed in the interstitial tissue of colorectal cancer (CRC) and its expression correlated with poor survival, high pathological grades and metastatic TNM stage in CRC patients. TCTP expression was greater in metastatic liver tissue than in primary tumors and was increased in highly invasive CRC cells. We demonstrated that the expression of TCTP was regulated by HIF-1α and its release was increased in response to low serum and hypoxic stress. Recombinant human TCTP (rhTCTP) promoted the migration and invasiveness of CRC cells in vitro and contributed to distant liver metastasis in vivo. Furthermore, rhTCTP activated Cdc42, phosphorylated JNK (p-JNK), increasing the translocation of p-JNK from the cytoplasm to the nucleus, as well as the secretion of MMP9. In addition, the expression of TCTP positively correlated with that of Cdc42 and p-JNK in clinical CRC samples. The silencing of Cdc42, JNK and MMP9 significantly inhibited the Matrigel invasion of rhTCTP-enhanced CRC cells. Collectively, these results identify a new role for extracellular TCTP as a promoter of CRC progression and liver metastases via Cdc42/JNK/MMP9 activation.

Upregulation of TCTP is associated with cholangiocarcinoma progression and metastasis

In order to investigate the role of translationally-controlled tumor protein (TCTP) in cholangiocarcinoma (CCA) progression and metastasis, TCTP protein staining in paraffin-embedded sections of human CCA tissue samples was examined using immunohistochemistry, and its expression was subsequently compared with clinicopathological parameters. Small interfering RNA (siRNA) targeting TCTP (siTCTP) were transfected into CCA cell lines to evaluate its effects on cellular functions. The proliferation, tumorigenicity and migration abilities of the transfected cells were measured using sulforhodamine B, clonogenic and would healing assays, respectively. The protein levels of TCTP and its associated molecules were evaluated by western blot analysis. Of the 119 individual cases of CCA tissues analyzed, high TCTP scores were significantly correlated with overall metastasis (P=0.044) and a shorter survival time (P<0.001). Multivariate proportional hazards analysis revealed that TCTP is an independent indicator of poor prognosis in CCA (hazard ratio =2.864; P<0.001). siTCTP transfection suppressed CCA cell growth and migration abilities, compared with the control cells (P<0.01). The siTCTP reduced the protein levels of focal adhesion kinase (FAK), phospho-FAK, nuclear factor kappa-light-chain-enhancer of activated B cells and matrix metalloproteinase 9, suggesting potential roles of TCTP in regulating CCA progression and metastasis. In conclusion, the upregulation of TCTP is clinically significant in patients with CCA, serving roles in CCA progression, particularly in cell survival and metastasis. Suppression of TCTP may serve as a potential target in CCA prevention and treatment.

Insights into the role and regulation of TCTP in skeletal muscle

The translationally controlled tumor protein (TCTP) is upregulated in a range of cancer cell types, in part, by the activation of the mechanistic target of rapamycin (mTOR). Recently, TCTP has also been proposed to act as an indirect activator of mTOR. While it is known that mTOR plays a major role in the regulation of skeletal muscle mass, very little is known about the role and regulation of TCTP in this post-mitotic tissue. This study shows that muscle TCTP and mTOR signaling are upregulated in a range of mouse models (mdx mouse, mechanical load-induced hypertrophy, and denervation- and immobilization-induced atrophy). Furthermore, the increase in TCTP observed in the hypertrophic and atrophic conditions occurred, in part, via a rapamycin-sensitive mTOR-dependent mechanism. However, the overexpression of TCTP was not sufficient to activate mTOR signaling (or increase protein synthesis) and is thus unlikely to take part in a recently proposed positive feedback loop with mTOR. Nonetheless, TCTP overexpression was sufficient to induce muscle fiber hypertrophy. Finally, TCTP overexpression inhibited the promoter activity of the muscle-specific ubiquitin proteasome E3-ligase, MuRF1, suggesting that TCTP may play a role in inhibiting protein degradation. These findings provide novel data on the role and regulation of TCTP in skeletal muscle in vivo.

Knockdown of translationally controlled tumor protein inhibits growth, migration and invasion of lung cancer cells

AIM

To investigate the role of translationally controlled tumor protein (TCTP) in lung cancer development.

MAIN METHODS

A549 and HCC827 cells were transfected with shRNA specifically targeting TCTP mRNA. Cell growth was assessed by colony formation assay and cell counting kit-8. Cell cycle and apoptosis were analyzed by flow cytometry. Cell migration and invasion was measured by scratch and transwell assays. In vivo tumorigenicity was evaluated by tumor xenografts in nude mice.

KEY FINDINGS

TCTP-silenced cells displayed a reduced ability of colony formation and a lower rate of proliferation in vitro. Knockdown of TCTP arrested cell cycle at G1 phase and led to downregulated expression of cyclins B1, D1 and E. Moreover, silencing of TCTP induced apoptosis and altered the levels of apoptosis-regulatory proteins such as cleaved caspase-3, Bcl-2, Bax and p53. Silencing of TCTP also inhibited migration and invasion of lung cancer cells. In addition, TCTP-silenced A549 cells, when subcutaneously inoculated in nude mice, formed tumors at a significantly slower rate.

SIGNIFICANCE

Our in vitro and in vivo data indicate that silencing of TCTP inhibits growth, migration and invasion of lung cancer cells. Thus, TCTP may be a potential target for lung cancer therapy.

Translationally controlled tumor protein (TCTP) is required for TGF-β1 induced epithelial to mesenchymal transition and influences cytoskeletal reorganization

Epithelial-mesenchymal transition (EMT) is a programed course of developmental changes resulting in the acquisition of invasiveness and mobility in cells. In cancer, this course is used by epithelial cells to attain movability. Translationally controlled tumor protein (TCTP) has been extensively characterized following the observation on tumor reversion ensuing its depletion. However, the role of TCTP in cancer progression is still elusive. Here, we demonstrate for the first time that TCTP is a target of transforming growth factor-β1 (TGF-β1), a key regulator of EMT in A549 cells. We here present changes in expression patterns of intermediate filament markers (vimentin and cytokeratin 18a) of EMT following TCTP knockdown or over expression. The TCTP over-expression in cancer cells is associated with mesenchymal characters, while downregulation promotes the epithelial markers in the cells. Interaction of TCTP with β-catenin seems to stabilize β-catenin, preparative to its nuclear localization highlighting a role for β-catenin signaling in EMT. Moreover, the induction of urokinase plasminogen activator (uPA) following ectopic expression of TCTP leads to destabilization of ECM. The cells knocked down for TCTP show diminished invasiveness and migration under TGF-β1 treatment. The present results for the first time demonstrate that TGF-β1 dependent TCTP expression is required for EMT in cells.

Inhibitory effect of blue light emitting diode on migration and invasion of cancer cells

The aim of this study was to determine the effects and molecular mechanism of blue light emitting diode (LED) in tumor cells. A migration and invasion assay for the metastatic behavior of mouse colon cancer CT-26 and human fibrosarcoma HT-1080 cells was performed. Cancer cell migration-related proteins were identified by obtaining a 2-dimensional gel electrophoresis (2-DE) in total cellular protein profile of blue LED-irradiated cancer cells, followed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis of proteins. Protein levels were examined by immunoblotting. Irradiation with blue LED inhibited CT-26 and HT-1080 cell migration and invasion. The anti-metastatic effects of blue LED irradiation were associated with inhibition of matrix metalloproteinase (MMP)-2 and MMP-9 expression. P38 MAPK phosphorylation was increased in blue LED-irradiated CT-26 and HT-1080 cells, but was inhibited after pretreatment with SB203580, a specific inhibitor of p38 MAPK. Inhibition of p38 MAPK phosphorylation by SB203580 treatment increased number of migratory cancer cells in CT-26 and HT-1080 cells, indicating that blue LED irradiation inhibited cancer cell migration via phosphorylation of p38 MAPK. Additionally blue LED irradiation of mice injected with CT-26 cells expressing luciferase decreased early stage lung metastasis compared to untreated control mice. These results indicate that blue LED irradiation inhibits cancer cell migration and invasion in vitro and in vivo.

Translationally controlled tumour protein TCTP is induced early in human colorectal tumours and contributes to the resistance of HCT116 colon cancer cells to 5-FU and oxaliplatin

Background

Translationally controlled tumour protein TCTP is an anti-apoptotic protein frequently overexpressed in cancers, where high levels are often associated with poor patient outcome. TCTP may be involved in protecting cancer cells against the cytotoxic action of anti-cancer drugs. Here we study the early increase of TCTP levels in human colorectal cancer (CRC) and the regulation of TCTP expression in HCT116 colon cancer cells, in response to treatment with the anti-cancer drugs 5-FU and oxaliplatin.

Methods

Using immunohistochemistry, we assessed TCTP levels in surgical samples from adenomas and adenocarcinomas of the colon, compared to normal colon tissue. We also studied the regulation of TCTP in HCT116 colon cancer cells in response to 5-FU and oxaliplatin by western blotting. TCTP mRNA levels were assessed by RT-qPCR. We used mTOR kinase inhibitors to demonstrate mTOR-dependent translational regulation of TCTP under these conditions. Employing the Real-Time Cell Analysis (RTCA) System and the MTS assay, we investigated the effect of TCTP-knockdown on the sensitivity of HCT116 cells to the anti-cancer drugs 5-FU and oxaliplatin.

Results

1. TCTP levels are significantly increased in colon adenomas and adenocarcinomas, compared to normal colon tissue. 2. TCTP protein levels are about 4-fold upregulated in HCT116 colon cancer cells, in response to 5-FU and oxaliplatin treatment, whereas TCTP mRNA levels are down regulated. 3. mTOR kinase inhibitors prevented the up-regulation of TCTP protein, indicating that TCTP is translationally regulated through the mTOR complex 1 signalling pathway under these conditions. 4. Using two cellular assay systems, we demonstrated that TCTP-knockdown sensitises HCT116 cells to the cytotoxicity caused by 5-FU and oxaliplatin.

Conclusions

Our results demonstrate that TCTP levels increase significantly in the early stages of CRC development. In colon cancer cells, expression of this protein is largely upregulated during treatment with the DNA-damaging anti-cancer drugs 5-FU and oxaliplatin, as part of the cellular stress response. TCTP may thus contribute to the development of anti-cancer drug resistance. These findings indicate that TCTP might be suitable as a biomarker and that combinatorial treatment using 5-FU/oxaliplatin, together with mTOR kinase inhibitors, could be a route to preventing the development of resistance to these drugs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-017-0164-3) contains supplementary material, which is available to authorized users.

The Translational Controlled Tumour Protein TCTP: Biological Functions and Regulation

The Translational Controlled Tumour Protein TCTP (gene symbol TPT1, also called P21, P23, Q23, fortilin or histamine-releasing factor, HRF) is a highly conserved protein present in essentially all eukaryotic organisms and involved in many fundamental cell biological and disease processes. It was first discovered about 35 years ago, and it took an extended period of time for its multiple functions to be revealed, and even today we do not yet fully understand all the details. Having witnessed most of this history, in this chapter, I give a brief overview and review the current knowledge on the structure, biological functions, disease involvements and cellular regulation of this protein.TCTP is able to interact with a large number of other proteins and is therefore involved in many core cell biological processes, predominantly in the response to cellular stresses, such as oxidative stress, heat shock, genotoxic stress, imbalance of ion metabolism as well as other conditions. Mechanistically, TCTP acts as an anti-apoptotic protein, and it is involved in DNA-damage repair and in cellular autophagy. Thus, broadly speaking, TCTP can be considered a cytoprotective protein. In addition, TCTP facilitates cell division through stabilising the mitotic spindle and cell growth through modulating growth signalling pathways and through its interaction with the proteosynthetic machinery of the cell. Due to its activities, both as an anti-apoptotic protein and in promoting cell growth and division, TCTP is also essential in the early development of both animals and plants.Apart from its involvement in various biological processes at the cellular level, TCTP can also act as an extracellular protein and as such has been involved in modulating whole-body defence processes, namely in the mammalian immune system. Extracellular TCTP, typically in its dimerised form, is able to induce the release of cytokines and other signalling molecules from various types of immune cells. There are also several examples, where TCTP was shown to be involved in antiviral/antibacterial defence in lower animals. In plants, the protein appears to have a protective effect against phytotoxic stresses, such as flooding, draught, too high or low temperature, salt stress or exposure to heavy metals. The finding for the latter stress condition is corroborated by earlier reports that TCTP levels are considerably up-regulated upon exposure of earthworms to high levels of heavy metals.Given the involvement of TCTP in many biological processes aimed at maintaining cellular or whole-body homeostasis, it is not surprising that dysregulation of TCTP levels may promote a range of disease processes, foremost cancer. Indeed a large body of evidence now supports a role of TCTP in at least the most predominant types of human cancers. Typically, this can be ascribed to both the anti-apoptotic activity of the protein and to its function in promoting cell growth and division. However, TCTP also appears to be involved in the later stages of cancer progression, such as invasion and metastasis. Hence, high TCTP levels in tumour tissues are often associated with a poor patient outcome. Due to its multiple roles in cancer progression, TCTP has been proposed as a potential target for the development of new anti-cancer strategies in recent pilot studies. Apart from its role in cancer, TCTP dysregulation has been reported to contribute to certain processes in the development of diabetes, as well as in diseases associated with the cardiovascular system.Since cellular TCTP levels are highly regulated, e.g. in response to cell stress or to growth signalling, and because deregulation of this protein contributes to many disease processes, a detailed understanding of regulatory processes that impinge on TCTP levels is required. The last section of this chapter summarises our current knowledge on the mechanisms that may be involved in the regulation of TCTP levels. Essentially, expression of the TPT1 gene is regulated at both the transcriptional and the translational level, the latter being particularly advantageous when a rapid adjustment of cellular TCTP levels is required, for example in cell stress responses. Other regulatory mechanisms, such as protein stability regulation, may also contribute to the regulation of overall TCTP levels.

Targeting TCTP with Sertraline and Thioridazine in Cancer Treatment

We have initially demonstrated in knocking down experiments that decreasing TCTP in cancer cells leads in some tissues to cell death while in others to a complete reorganization of the tumor into architectural structures reminiscent of normal ones. Based on these experiments and a series of other findings confirming the key role of TCTP in cancer, it became important to find pharmacological compounds to inhibit its function, and this became for us a priority. In the present text, we explain in detail the experiments that were performed and the perspectives of sertraline in cancer treatment, as this became today a reality with a clinical study that started in collaboration with Columbia University and Johns Hopkins University.

Relationship between proton pump inhibitors and tumors

Proton pump inhibitors (PPIs) as benzene and imidazole derivatives are in essence H⁺-K⁺-ATPases inhibitors, and they are commonly used in the treatment of acid related diseases such as gastric ulcer. In recent years, exploring the relationship between PPIs and tumors has become a hot research topic. This paper summarizes the relationship of PPIs with tumor microenvironment, the improvement of drug resistance mechanisms, and related signaling pathways, with an aim to provide clues for the treatment of tumors.

RNA interference‑mediated knockdown of translationally controlled tumor protein induces apoptosis, and inhibits growth and invasion in glioma cells

Translationally controlled tumor protein (TCTP) is a highly conserved, growth-associated and small molecule protein, which is highly expressed in various types of tumor cell. TCTP can promote the growth and suppress apoptosis of tumor cels. However, few studies have reported the effects of TCTP in gliomas. In the present study, a glioma cell line was established, which was stably transfected with TCTP short hairpin ribonucleic acid (shRNA), to investigate the impact of downregulated expression of TCTP on the proliferation, apoptosis and invasion of glioma cells. Western blot and reverse transcription-quantitative polymerase chain reaction analyses demonstrated that TCTP shRNA effectively reduced the expression of TCTP in the U251 glioma cell line. MTT and colony formation assays revealed that downregulated expression of TCTP significantly inhibited glioma cell proliferation. Cell cycle analysis using flow cytometry revealed that the cells in the pRNA-H1.1-TCTP group were arrested in the G0/G1 phase of the cell cycle. Western blot analysis detected downregulated expression levels of cyclins, including Cyclin D1, Cyclin E and Cyclin B. Annexin V-fluorescein isothiocyanate/propidium iodide and Hoechst staining demonstrated that the apoptotic rate of the cells in the pRNA-H1.1-TCTP group was significantly higher than that of the cells in the pRNA-H1.1-control group, with upregulated expression levels of B-cell-associated X protein and cleaved-caspase-3 and downregulated expression of B-cell lmyphoma-2 in the apoptotic process. Wound healing and Transwell assays revealed that downregulated expression of TCTP significantly inhibited the migration and invasiveness of the glioma cells; and the expression levels and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were also significantly affected. In conclusion, the present study demonstrated that downregulated expression of TCTP significantly inhibited proliferation and invasion, and induced apoptosis in the glioma cells. These results suggested that TCTP may be important in glioma development and metastasis. Therefore, TCTP is expected to become an effective target for glioma gene therapy.

TCTP Expression After Rat Spinal Cord Injury: Implications for Astrocyte Proliferation and Migration

Translationally controlled tumor protein (TCTP) is a ubiquitous and highly conserved protein which plays a role in cell proliferation and growth, apoptosis, and cell cycle regulation. However, its expression and function in spinal cord injury (SCI) are still unknown. Here, we demonstrated that expression of TCTP was dynamic changed after acute spinal cord injury. Our results showed that TCTP gradually increased, reached a peak at 3 day, and then declined to basal levels at 14 days after spinal cord injury. Upregulation of TCTP was accompanied with an increase in the levels of proliferation proteins such as PCNA. Immunofluorescent labeling also showed that TCTP located in astrocytes and traumatic SCI induced TCTP colocalizated with PCNA. These results indicated that TCTP might play an important role in astrocyte proliferation. To further probe the role of TCTP, TCTP-specific siRNA-transfected astrocytes showed significant decrease of primary astrocyte proliferation. Surprisingly, TCTP knockdown also reduced primary astrocyte migration, as the reorganization of microtubules and F-actin was disturbed after siRNA transfection. All above indicated that TCTP might play a crucial role in astrocyte proliferation and migration. Collectively, our data suggested that TCTP might play important roles in CNS pathophysiology after SCI.

Translationally controlled tumor protein induces epithelial to mesenchymal transition and promotes cell migration, invasion and metastasis

Translationally controlled tumor protein (TCTP), is a highly conserved protein involved in fundamental processes, such as cell proliferation and growth, tumorigenesis, apoptosis, pluripotency, and cell cycle regulation. TCTP also inhibits Na,K-ATPase whose subunits have been suggested as a marker of epithelial-to-mesenchymal transition (EMT), a crucial step during tumor invasiveness, metastasis and fibrosis. We hypothesized that, TCTP might also serve as an EMT inducer. This study attempts to verify this hypothesis. We found that overexpression of TCTP in a porcine renal proximal tubule cell line, LLC-PK1, induced EMT-like phenotypes with the expected morphological changes and appearance of EMT related markers. Conversely, depletion of TCTP reversed the induction of these EMT phenotypes. TCTP overexpression also enhanced cell migration via activation of mTORC2/Akt/GSK3β/β-catenin, and invasiveness by activating MMP-9. Moreover, TCTP depletion in melanoma cells significantly reduced pulmonary metastasis by inhibiting the development of mesenchymal-like phenotypes. Overall, these findings support our hypothesis that TCTP is a positive regulator of EMT and suggest that modulation of TCTP expression is a potential approach to inhibit the invasiveness and migration of cancer cells and the attendant pathologic processes including metastasis.

Expression and clinical role of TCTP in epithelial ovarian cancer

The aim of this study is to investigate the potential role and prognostic significance of translationally controlled tumor protein (TCTP) in human epithelial ovarian cancer (EOC). Western blot was used to evaluate the expression of TCTP in eight fresh EOC tissues. Immunohistochemistry was performed on formalin-fixed paraffin-embedded sections of 119 cases of ovarian cancers. Kaplan-Meier method indicated the relation between TCTP and EOC patients' overall survival rate. Starvation and re-feeding was used to assess cell cycle. Knocking down of TCTP and CCK8 assay showed the role of TCTP in HO8910 cell cycle. We found that TCTP was overexpressed in carcinoma tissues compared with normal tissues. Immunohistochemistry revealed that TCTP expression was significantly associated with clinicopathologic variables. Kaplan-Meier analysis revealed that high TCTP expression was significantly related to poor prognosis of the patients. Starvation and re-feeding suggested TCTP played a critical role in HO8910 cell proliferation. Interference of TCTP and CCK8 assay showed that the TCTP-siRNA treated HO8910 cells grew more slowly than the control group. CCK-8 assays and terminal-deoxynucleoitidyl transferase mediated nick end labeling assays were also performed to demonstrate the cisplatin could inhibit the survival of HO8910 cells and promote their apoptosis. All the experiments we have done showed that TCTP could promote the progression of EOC and reduce the sensitiveness of HO8910 cells to cisplatin.

Helminthes and insects: maladies or therapies

By definition, parasites cause harm to their hosts. But, considerable evidence from ancient traditional medicine has supported the theory of using parasites and their products in treating many diseases. Maggots have been used successfully to treat chronic, long-standing, infected wounds which failed to respond to conventional treatment by many beneficial effects on the wound including debridement, disinfection, and healing enhancement. Maggots are also applied in forensic medicine to estimate time between the death and discovery of a corpse and in entomotoxicology involving the potential use of insects as alternative samples for detecting drugs and toxins in death investigations. Leeches are segmented invertebrates, famous by their blood-feeding habits and used in phlebotomy to treat various ailments since ancient times. Leech therapy is experiencing resurgence nowadays in health care principally in plastic and reconstructive surgery. Earthworms provide a source of medicinally useful products with potential antimicrobial, antiviral, and anticancer properties. Lumbrokinases are a group of fibrinolytic enzymes isolated and purified from earthworms capable of degrading plasminogen-rich and plasminogen-free fibrin and so can be used to treat various conditions associated with thrombotic diseases. Helminth infection has been proved to have therapeutic effects in both animal and human clinical trials with promising evidence in treating many allergic diseases and can block the induction of or reduce the severity of some autoimmune disorders as Crohn's disease or ulcerative colitis. What is more, venomous arthropods such as scorpions, bees, wasps, spiders, ants, centipedes, snail, beetles, and caterpillars. The venoms and toxins from these arthropods provide a promising source of natural bioactive compounds which can be employed in the development of new drugs to treat diseases as cancer. The possibility of using these active molecules in biotechnological processes can make these venoms and toxins a valuable and promising source of natural bioactive compounds. The therapeutic use of helminthes and insects will be of great value in biomedicine and further studies on insect toxins will contribute extensively to the development of Biomedical Sciences.

Tumor protein translationally controlled 1 is a p53 target gene that promotes cell survival

Tumor suppressor p53 maintains genome stability by differentially activating target genes that control diverse cellular responses, such as the antioxidant response, cell cycle arrest and apoptosis. Despite the fact that many p53 downstream genes have been well characterized, novel p53 target genes are continuously being identified. Here, we report that Tpt1 is a direct target gene of p53. We found that p53 upregulates the transcription of Tpt1 and identified a p53-responsive element in the promoter of the mouse Tpt1 gene. Furthermore, p53-dependent induction of Tpt1 was able to reduce oxidative stress, minimize apoptosis, and promote cell survival in response to H 2O2 challenge. In addition, a positive correlation between the expression of p53 and Tpt1 only existed in normal lung tissues, not in lung tumors. Such positive correlation was also found in lung cell lines that contain wild-type p53, but not mutated p53. Based on the important role of Tpt1 in cancer development, chemoresistance, and cancer reversion, identification of Tpt1 as a direct target gene of p53 not only adds to the complexity of the p53 network, but may also open up a new avenue for cancer prevention and intervention.

TCTP as therapeutic target in cancers

The translationally controlled tumor protein (TCTP) is a highly conserved protein present in eukaryotic organisms. This protein, located both in the cytoplasmic and the nucleus, is expressed in various tissues and is regulated in response to a wide range of extracellular stimuli. TCTP interacts with itself and other protein including MCL1 and p53. TCTP has been shown to play an important role in physiological events, such as cell proliferation, cell death and immune responses but also in stress response and tumor reversion. Moreover, TCTP expression is associated with malignancy and chemoresistance. In this review, we will evaluate pathways regulated by TCTP and current inhibitory strategy to target TCTP in cancerous diseases.

The C-terminal cysteine of turbot Scophthalmus maximus translationally controlled tumour protein plays a key role in antioxidation and growth-promoting functions

The translationally controlled tumour protein (TCTP) of turbot Scophthalmus maximus (SmTCTP) contains only one cysteine (Cys¹⁷⁰) at the C-terminal end. The biological role of this C-terminal Cys¹⁷⁰ in the antioxidation and growth-promoting functions of SmTCTP was examined by site-directed mutation of C170A (Cys¹⁷⁰ →Ala¹⁷⁰). It was found that C170A mutation not only obviously decreased the antioxidation capacity of the mutant-smtctp-transformed bacteria exposed to 0·22 mM hydrogen peroxide, but also significantly interrupted the normal growth and survival of the mutant-smtctp-transformed bacteria and flounder Paralichthys olivaceus gill (FG) cells, indicating a key role played by Cys¹⁷⁰ in the antioxidation and growth-promoting functions of SmTCTP. This study also suggested that the self-dimerization or dimerization with other interacting proteins is critical to the growth-promoting function of SmTCTP.

Identification of altered plasma proteins by proteomic study in valvular heart diseases and the potential clinical significance

BACKGROUND

Little is known about genetic basis and proteomics in valvular heart disease (VHD) including rheumatic (RVD) and degenerative (DVD) valvular disease. The present proteomic study examined the hypothesis that certain proteins may be associated with the pathological changes in the plasma of VHD patients.

METHODS AND RESULTS

Differential protein analysis in the plasma identified 18 differentially expressed protein spots and 14 corresponding proteins or polypeptides by two-dimensional electrophoresis and mass spectrometry in 120 subjects. Two up-regulated (complement C4A and carbonic anhydrase 1) and three down-regulated proteins (serotransferrin, alpha-1-antichymotrypsin, and vitronectin) were validated by ELISA in enlarging samples. The plasma levels (n = 40 for each) of complement C4A in RVD (715.8±35.6 vs. 594.7±28.2 ng/ml, P = 0.009) and carbonic anhydrase 1 (237.70±15.7 vs. 184.7±10.8 U/L, P = 0.007) in DVD patients were significantly higher and that of serotransferrin (2.36±0.20 vs. 2.93±0.16 mg/ml, P = 0.025) and alpha-1-antichymotrypsin (370.0±13.7 vs. 413.0±11.6 µg/ml, P = 0.019) in RVD patients were significantly lower than those in controls. The plasma vitronectin level in both RVD (281.3±11.0 vs. 323.2±10.0 µg/ml, P = 0.006) and DVD (283.6±11.4 vs. 323.2±10.0 µg/ml, P = 0.011) was significantly lower than those in normal controls.

CONCLUSIONS

We have for the first time identified alterations of 14 differential proteins or polypeptides in the plasma of patients with various VHD. The elevation of plasma complement C4A in RVD and carbonic anhydrase 1 in DVD and the decrease of serotransferrin and alpha-1-antichymotrypsin in RVD patients may be useful biomarkers for these valvular diseases. The decreased plasma level of vitronectin - a protein related to the formation of valvular structure - in both RVD and DVD patients might indicate the possible genetic deficiency in these patients.

Changes on the Caco-2 secretome through differentiation analyzed by 2-D differential in-gel electrophoresis (DIGE)

Colorectal cancer is still a major health burden worldwide, and its diagnosis has not improved in recent years due to a lack of appropriate diagnostic serum markers. Aiming to find new diagnostic proteins, we applied the proteomic DIGE technology to analyze changes in the secretome before/after differentiation of the colon adenocarcinoma Caco-2 cell line, an accepted in vitro model to study colorectal tumorigenesis. When the secretomes from undifferentiated (tumor-like) and differentiated cells (resembling healthy enterocytes) were compared, we found 96 spots differentially expressed. After MS/MS analysis, 22 spots corresponding to 15 different proteins were identified. Principal component analysis demonstrated these 22 spots could serve as a discriminatory panel between the tumor-like and normal-like cells. Among the identified proteins, the translationally-controlled tumor protein (TCTP), the transforming growth factor-beta-induced protein ig-h3 (TGFβIp), and the Niemann-Pick disease type C2 protein (NPC2) are interesting candidates for future studies focused on their utility as serum biomarkers of colorectal cancer.

Cytoplasmic and nuclear localization of TCTP in normal and cancer cells

Objective. Intracellular localization of translationally controlled tumour protein (TCTP) was investigated in cancer cells. Methods. The expression and localization of TCTP were detected at 12 h, 24 h, 48 h, 60 h time points in culture of human hepatocarcinoma cell line HepG2, human cervical carcinoma cell line HeLa, and human normal liver cell line HL-7702 by immunofluorescence. Results. TCTP was expressed in both normal and tumor cells, and its localization changes at different time points. TCTP was mainly expressed in cytoplasm from 24 h to 48 h then expressed in both nucleus and cytoplasm at 60 h in HL-7702 cells. While in HepG2 cells, TCTP first localized at cell membrane within 24 h then at both nucleus and cytoplasm from 48 h to 60 h; TCTP localized at both nucleus and cytoplasm from 12 h to 60 h in Hela cells. Conclusion. The translocation of intracellular expression of TCTP in normal and tumor cells at different time points may pave a path to the studying of TCTP role in tumor growth.

Role of translationally controlled tumor protein in cancer progression

Translationally controlled tumor protein (TCTP) is a highly conserved and ubiquitously expressed protein in all eukaryotes-highlighting its important functions in the cell. Previous studies revealed that TCTP is implicated in many biological processes, including cell growth, tumor reversion, and induction of pluripotent stem cell. A recent study on the solution structure from fission yeast orthologue classifies TCTP under a family of small chaperone proteins. There is growing evidence in the literature that TCTP is a multifunctional protein and exerts its biological activity at the extracellular and intracellular levels. Although TCTP is not a tumor-specific protein, our research group, among several others, focused on the role(s) of TCTP in cancer progression. In this paper, we will summarize the current scientific knowledge of TCTP in different aspects, and the precise oncogenic mechanisms of TCTP will be discussed in detail.

Dissecting molecular events in thyroid neoplasia provides evidence for distinct evolution of follicular thyroid adenoma and carcinoma

Benign hypofunctional cold thyroid nodules (CTNs) are a frequent scintiscan finding and need to be distinguished from thyroid carcinomas. The origin of CTNs with follicular morphologic features is unresolved. The DNA damage response might act as a physiologic barrier, inhibiting the progression of preneoplastic lesions to neoplasia. We investigated the following in hypofunctional follicular adenoma (FA) and follicular thyroid cancer (FTC): i) the mutation rate of frequently activated oncogenes, ii) the activation of DNA damage response checkpoints, and iii) the differential proteomic pattern between FA and FTC. Both FTC and FA, which did not harbor RAS, phosphoinositide-3-kinase, or PAX/peroxisome proliferator activated receptor-γ mutations, express various proteins in common and others that are more distinctly expressed in FTC rather than in FA or normal thyroid tissue. This finding is in line with the finding of constitutive DNA damage checkpoint activation (p-Chk2, γ-H2AX) and evidence for replicative stress causing genomic instability (increased cyclin E, retinoblastoma, or E2F1 mRNA expression) in FTC but not FA. We discuss the findings of the increased expression of translationally controlled tumor protein, phosphatase 2A inhibitor, and DJ-1 in FTC compared with FA identified by proteomics and their potential implication in follicular thyroid carcinogenesis. Our present findings argue for the definition of FA as a truly benign entity and against progressive development of FA to FTC.

Expression of translationally controlled tumor protein (TCTP) in the uterus of mice of early pregnancy and its possible significance during embryo implantation

BACKGROUND

Translationally controlled tumor protein (TCTP) is a highly conserved, growth-related protein. Previous studies showed that TCTP is involved in many biological processes and it is essential for early embryo development and proliferation of embryonic stem cells. However, whether TCTP plays a role during embryo implantation remains unclear. This paper examines the expression and the role of TCTP in the uterus of mice during early pregnancy.

METHODS

The expression of TCTP in the uterus of mice during early pregnancy was examined by quantitative real-time PCR, immunohistochemistry and western blot. A functional study of TCTP in embryo implantation of mice was also performed by intrauterine injection with antisense oligodeoxynucleotides (A-ODNs) of TCTP on day 3 (D3) of pregnancy.

RESULTS

The TCTP mRNA levels were significantly upgraded from D3 to D5 of pregnancy and reached maximum levels on D5, then dramatically decreased on D6 and D7. The levels of the TCTP protein detected by western blot were consistent with those of the mRNA. Immunohistochemistry analysis showed that the TCTP protein was mainly located in the luminal and the glandular epithelium on D1 and D2 of pregnancy and reached maximum levels on D5 in the luminal and glandular epithelium and in the stromal cells. The levels of TCTP in the pseudo-pregnant uterus of mice were lower than those of pregnant mice on D4 and D6. Furthermore, inhibiting the TCTP expression by intrauterine injection with A-ODNs of TCTP on D3 of pregnancy significantly reduced the number of the implanted embryos compared with the control.

CONCLUSIONS

This study demonstrated that TCTP may play a significant role in embryo implantation in mice.

Preparation and characterization of monoclonal antibody against translationally controlled tumor protein

From our previous proteomic research, we found that translationally controlled tumor protein (TCTP) might play at least a partial role in colon adenocarcinoma progression. However, the precise impact of TCTP on colorectal cancer metastasis progression is currently still unknown. Therefore, immunology reagents are urgently needed to proceed with the next mechanism-related research. Moreover, the identification of TCTP expression level in tissue of colorectal cancer patients also requires substantial amounts of immunology reagents. In this report, monoclonal antibodies (MAbs) against to TCTP were made from hyperimmune Balb/c mice, by injecting 50 μg of purified antigen intraperitoneally. Hybridomas were screened by indirect enzyme-linked immunosorbent assay (ELISA) using purified protein. Finally six mouse hybridomas producing MAbs to TCTP were established. The MAbs obtained were fully characterized using Western blot analysis and immunohistochemistry. The results showed that these antibodies could be used for the preliminary application of the next mechanism-related research and TCTP expression level analysis.

TCTP is a critical survival factor that protects cancer cells from oxidative stress-induced cell-death

The translationally controlled tumor protein (TCTP) displays growth-promoting and antiapoptotic properties. To gain information on the role of TCTP in cancer disease, we studied the modulation of TCTP and cell survival under stress conditions on tumor cell lines of different origins. When cancer cells were exposed to a mild oxidative stress, such low doses of Arsenic trioxide (ATO) or hydrogen peroxide (H(2)O(2)), up-regulation of TCTP was observed in cells survived to the treatment. Differently, a strong oxidative hit provided by ATO combined with glutathione (GSH) depletion or condition of glucose deprivation caused a down-modulation of TCTP followed by cell death. Clones with a forced expression of TCTP or with silenced TCTP were obtained from the breast cancer cell line MDA-MB-231. The sensitivity to oxidative stress was strongly enhanced in down-modulated TCTP cells while decreasing in cells with high levels of TCTP. Together these results indicate that TCTP is a survival factor that protects cancer cells from oxidative stress-induced cell-death. We propose TCTP as a "stress hallmark" that may be exploited as a therapeutic target to decrease the resistance of cancer cells to anticancer therapy.

Brown spider (Loxosceles genus) venom toxins: tools for biological purposes

Venomous animals use their venoms as tools for defense or predation. These venoms are complex mixtures, mainly enriched of proteic toxins or peptides with several, and different, biological activities. In general, spider venom is rich in biologically active molecules that are useful in experimental protocols for pharmacology, biochemistry, cell biology and immunology, as well as putative tools for biotechnology and industries. Spider venoms have recently garnered much attention from several research groups worldwide. Brown spider (Loxosceles genus) venom is enriched in low molecular mass proteins (5–40 kDa). Although their venom is produced in minute volumes (a few microliters), and contain only tens of micrograms of protein, the use of techniques based on molecular biology and proteomic analysis has afforded rational projects in the area and permitted the discovery and identification of a great number of novel toxins. The brown spider phospholipase-D family is undoubtedly the most investigated and characterized, although other important toxins, such as low molecular mass insecticidal peptides, metalloproteases and hyaluronidases have also been identified and featured in literature. The molecular pathways of the action of these toxins have been reported and brought new insights in the field of biotechnology. Herein, we shall see how recent reports describing discoveries in the area of brown spider venom have expanded biotechnological uses of molecules identified in these venoms, with special emphasis on the construction of a cDNA library for venom glands, transcriptome analysis, proteomic projects, recombinant expression of different proteic toxins, and finally structural descriptions based on crystallography of toxins.

Proteome profiling of Epstein-Barr virus infected nasopharyngeal carcinoma cell line: identification of potential biomarkers by comparative iTRAQ-coupled 2D LC/MS-MS analysis

Epstein-Barr virus (EBV) has been implicated in the development of nasopharyngeal carcinoma (NPC), a squamous cell carcinoma with high-occurrence in Southeast Asia and southern China. However, the underlying relationship of EBV and NPC squamous cell remains obscure. In this study, we employ a comparative iTRAQ-coupled 2D LC-MS/MS system to analyze the protein profile of NPC cell line upon EBV infection. Based on the proteome data and Western blot validation, 12 proteins were found to be significantly up-regulated and associated with signal transduction, cytoskeleton formation, metabolic pathways and DNA bindings. The interactions among NPC and EBV proteins were further analyzed and protein networks were established. Based on the functions of differentially expressed proteins, a metabolic pathway was proposed to elucidate their relationship in cytoskeleton formation, cell proliferation and apoptosis. Our results suggested a new proteome platform to analyze EBV's role in NPC squamous cell line. And these differentially expressed proteins may hold the promise as potential biomarkers for NPC diagnostics and treatment.

Mechanics and regulation of cell shape during the cell cycle

Many cell types undergo dramatic changes in shape throughout the cell cycle. For individual cells, a tight control of cell shape is crucial during cell division, but also in interphase, for example during cell migration. Moreover, cell cycle-related cell shape changes have been shown to be important for tissue morphogenesis in a number of developmental contexts. Cell shape is the physical result of cellular mechanical properties and of the forces exerted on the cell. An understanding of the causes and repercussions of cell shape changes thus requires knowledge of both the molecular regulation of cellular mechanics and how specific changes in cell mechanics in turn effect global shape changes. In this chapter, we provide an overview of the current knowledge on the control of cell morphology, both in terms of general cell mechanics and specifically during the cell cycle.

Roles of the translationally controlled tumour protein (TCTP) and the double-stranded RNA-dependent protein kinase, PKR, in cellular stress responses

Translationally controlled tumour protein (TCTP) is a highly conserved protein present in all eukaryotic organisms. Various cellular functions and molecular interactions have been ascribed to this protein, many related to its growth-promoting and antiapoptotic properties. TCTP levels are highly regulated in response to various cellular stimuli and stresses. We have shown recently that the double-stranded RNA-dependent protein kinase, PKR, is involved in translational regulation of TCTP. Here we extend these studies by demonstrating that TCTP is downregulated in response to various proapoptotic treatments, in particular agents that induce Ca(++) stress, in a PKR-dependent manner. This regulation requires phosphorylation of protein synthesis factor eIF2alpha. Since TCTP has been characterized as an antiapoptotic and Ca(++)-binding protein, we asked whether it is involved in protecting cells from Ca(++)-stress-induced apoptosis. Overexpression of TCTP partially protects cells against thapsigargin-induced apoptosis, as measured using caspase-3 activation assays, a nuclear fragmentation assay, using fluorescence-activated cell sorting analysis, and time-lapse video microscopy. TCTP also protects cells against the proapoptotic effects of tunicamycin and etoposide, but not against those of arsenite. Our results imply that cellular TCTP levels influence sensitivity to apoptosis and that PKR may exert its proapoptotic effects at least in part through downregulation of TCTP via eIF2alpha phosphorylation.