TCTP/HRF pathway and angiogenesis: A feasible intercourse in chronic lymphocytic leukemia

Targeting inhibition of TCTP could inhibit proliferation and induce apoptosis in AML cells

Translationally controlled tumor protein (TCTP) is a highly conserved multifunctional protein, which participates in many important physiological processes. Recently, the roles of TCTP in cell proliferation and apoptosis, especially its close relationship with various tumors, have attracted widespread attention. In this study, we found that the protein level of TCTP was significantly reduced in acute promyelocytic leukemia cell line NB4 transfected with retinoic acid-induced gene G (RIG-G). The RIG-G was found in our previous work as a key mediator of anti-proliferative activity in retinoid/interferon-related pathways. Here, we tried to further explore the function of TCTP in the development of acute myeloid leukemia (AML) from different levels. Our results showed that inhibiting TCTP expression could attenuate AML cells proliferation and induce apoptosis both in AML cell lines and in xenograft of NOD-SCID mice. In addition, either compared with patients in complete remission or non-leukemia patients, we detected that the expression of TCTP was generally high in the fresh bone marrow of AML patients, suggesting that there was a certain correlation between TCTP and AML disease progression. Taken together, our study revealed the role of TCTP in AML development, and provided a potential target for AML treatment.

Harnessing the value of TCTP in breast cancer treatment resistance: an opportunity for personalized therapy

Early identification of breast cancer (BC) patients at a high risk of progression may aid in therapeutic and prognostic aims. This is especially true for metastatic disease, which is responsible for most cancer-related deaths. Growing evidence indicates that the translationally controlled tumor protein (TCTP) may be a clinically relevant marker for identifying poorly differentiated aggressive BC tumors. TCTP is an intriguing protein with pleiotropic functions, which is involved in multiple signaling pathways. TCTP may also be involved in stress response, cell growth and proliferation-related processes, underlying its potential role in the initiation of metastatic growth. Thus, TCTP marks specific cancer cell sub-populations with pronounced stress adaptation, stem-like and immune-evasive properties. Therefore, we have shown that in vivo phospho-TCTP levels correlate with the response of BC cells to anti-HER2 agents. In this review, we discuss the clinical relevance of TCTP for personalized therapy, specific TCTP-targeting strategies, and currently available therapeutic agents. We propose TCTP as an actionable clinically relevant target that could potentially improve patient outcomes.

Upregulation of Translationally Controlled Tumor Protein Is Associated With Cervical Cancer Progression

Outside a few affluent countries with adequate vaccination and screening coverage, cervical cancer remains the leading cause of cancer-related deaths in women in many countries. Currently, a major problem is that a substantial proportion of patients are already at an advanced cancer stage when diagnosed. There is increasing evidence that indicates the involvement of translationally controlled tumor protein 1 (TPT1) overexpression in cancer development, but little is known about its implication in cervical cancer. We assessed the levels of TPT1 in surgical tissue and sera of patients with cervicitis, cervical intraepithelial neoplasia III, and cervical cancer, as well as in normal and cancerous cervical cell lines. Gene sets, pathways, and functional protein interactions associated with TPT1 were identified using the TCGA data cohort of cervical cancer. We found that the TPT1 expression was significantly increased in cervical cancer tissue compared to all nonmalignant cervical tissues, including samples of cervicitis, cervical intraepithelial neoplasia III, and normal controls. Serum level of TPT1 was also increased in cervical cancer patients compared to healthy subjects. Furthermore, elevated TPT1 expression was significantly correlated with lymph node metastasis and a low differentiation degree of the cancer. In the cancerous tissues and cell lines, selective markers of PI3K/AKT/mTOR pathway over-activation, apoptosis repression, and EMT were detected, and their interaction with TPT1 was supported by biometrics analyses. Our results, for the first time, demonstrate a strong correlation of upregulated TPT1 expression with cervical cancer progression, suggesting that TPT1 might provide a potential biomarker for cervical cancer progression.

Immunomolecular evaluation of dihydroartemisinin effects on apoptosis in chronic lymphocytic leukemia cell lines

INTRODUCTION

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, has recently shown to induce apoptosis in many types of cancer cells. In this study, we aimed to determine the effects of DHA on apoptosis in human chronic lymphocytic leukemia (CLL) cell lines.

METHODS

The cells were treated separately and combined by DHA and Fludurabine (FLU) during 24, 48 and 72 hours. The cell viabilities determined by XTT method. Following separate and combined treatment of IC50 concentrations of DHA and FLU to the cells during 24 hours, the cells were analyzed by flow cytometry to determine the effects on apopotis staining with AnnexinV FITC and PI. mRNA and protein expression levels of TCTP, Mcl-1, Bcl-2, Bax and Caspase-3 were analyzed to find out the molecular mechanisms of apoptosis by using quantitative real-time PCR and flow cytometric methods.

RESULTS

Treatment with DHA alone or in combination with FLU induced apoptosis in a dose dependent manner in CLL cells. DHA alone was more effective than FLU alone or combined treatment with DHA and FLU. Our results suggest that Bcl-2 protein family member Bax was active in the apoptotic response of CLL cells after DHA treatment. Moreover, the apoptotic response induced by DHA was independent from the p53 mutation status of the CLL cells.

CONCLUSION

DHA might be a potential anti-cancer therapeutic for CLL.

A novel ligand of the translationally controlled tumor protein (TCTP) identified by virtual drug screening for cancer differentiation therapy

Introduction Differentiation therapy is a promising strategy for cancer treatment. The translationally controlled tumor protein (TCTP) is an encouraging target in this context. By now, this field of research is still at its infancy, which motivated us to perform a large-scale screening for the identification of novel ligands of TCTP. We studied the binding mode and the effect of TCTP blockade on the cell cycle in different cancer cell lines. Methods Based on the ZINC-database, we performed virtual screening of 2,556,750 compounds to analyze the binding of small molecules to TCTP. The in silico results were confirmed by microscale thermophoresis. The effect of the new ligand molecules was investigated on cancer cell survival, flow cytometric cell cycle analysis and protein expression by Western blotting and co-immunoprecipitation in MOLT-4, MDA-MB-231, SK-OV-3 and MCF-7 cells. Results Large-scale virtual screening by PyRx combined with molecular docking by AutoDock4 revealed five candidate compounds. By microscale thermophoresis, ZINC10157406 (6-(4-fluorophenyl)-2-[(8-methoxy-4-methyl-2-quinazolinyl)amino]-4(3H)-pyrimidinone) was identified as TCTP ligand with a K_D of 0.87 ± 0.38. ZINC10157406 revealed growth inhibitory effects and caused G0/G1 cell cycle arrest in MOLT-4, SK-OV-3 and MCF-7 cells. ZINC10157406 (2 × IC50) downregulated TCTP expression by 86.70 ± 0.44% and upregulated p53 expression by 177.60 ± 12.46%. We validated ZINC10157406 binding to the p53 interaction site of TCTP and replacing p53 by co-immunoprecipitation. Discussion ZINC10157406 was identified as potent ligand of TCTP by in silico and in vitro methods. The compound bound to TCTP with a considerably higher affinity compared to artesunate as known TCTP inhibitor. We were able to demonstrate the effect of TCTP blockade at the p53 binding site, i.e. expression of TCTP decreased, whereas p53 expression increased. This effect was accompanied by a dose-dependent decrease of CDK2, CDK4, CDK, cyclin D1 and cyclin D3 causing a G0/G1 cell cycle arrest in MOLT-4, SK-OV-3 and MCF-7 cells. Our findings are supposed to stimulate further research on TCTP-specific small molecules for differentiation therapy in oncology.

AMG900 as novel inhibitor of the translationally controlled tumor protein

INTRODUCTION

Cancer is one of the leading causes of death worldwide. Classical cytotoxic chemotherapy exerts high side effects and low tumor selectivity. Translationally controlled tumor protein (TCTP) is a target for differentiation therapy, a promising, new therapeutic approach, which is expected to be more selective and less toxic than cytotoxic chemotherapy. The aim of the present investigation was to identify novel TCTP inhibitors.

METHODS

We performed in silico screening and molecular docking using a chemical library of more than 31,000 compounds to identify a novel inhibitor of TCTP. We tested AMG900 in vitro for binding to TCTP by microscale thermophoresis and co-immunoprecipitation. Additionally, we examined the effect of TCTP blockade on cell cycle progression by flow cytometry and Western blotting and cancer cell survival by resazurin assays in MCF-7, SK-OV3 and MOLT-4 cell lines.

RESULTS

We identified AMG900 as new inhibitor of TCTP. AMG900 bound to the p53 binding site of TCTP with a free binding energy of -9.63 ± 0.01 kcal/mol. This compound decreased TCTP expression to 23.4 ± 1.59% and increased p53 expression to 194.29 ± 24.27%. Furthermore, AMG900 induced G0/G1 arrest as shown by flow cytometry and Western blot of relevant cell cycle proteins. AMG900 decreased CDK2, CDK4, CDK6, cyclin D1 and cyclin D3 expression, whereas p18, p21 and p27 expression increased. Moreover, AMG900 disturbed TCTP-p53 complexation as shown by co-immunoprecipitation and increased expression of free p53.

DISCUSSION

AMG900 may serve as novel lead compound for the development of differentiation therapy approaches against cancer.

Function of translationally controlled tumor protein (TCTP) in Eudrilus eugeniae regeneration

TCTP (Translationally Controlled Tumour Protein) is a multifunctional protein that plays a role in the development, immune system, tumour reversion, and maintenance of stem cells. The mRNA of the Tpt1 gene is over-expressed during liver regeneration. But, the function of the protein in regeneration is not known. To study the role of the protein in regeneration, the earthworm Eudrilus eugeniae was chosen. First, the full length cDNA of the Tpt1 gene was sequenced. The size of the cDNA is 504 bp and the protein has 167 amino acids. The highest level of TCTP expression was documented in the worm after three days of regeneration. The protein was found to be expressed specifically in the epithelial layer of the skin. During regeneration, the protein expression was found to be the highest at the tip of blastema. The pharmacological suppression of TCTP using nutlin-3 and TCTP RNAi experiments resulted in the failure of the regeneration process. The suppression of TCTP caused the arrest of proliferation in posterior amputated worms. The severe cell death was documented in the amputated region of nutlin-3 injected worm. The silencing of TCTP has blocked the modification of clitellar segments. The experiments confirm that TCTP has major functions in the upstream signalling of cell proliferation in the early regeneration process in E. eugeniae.

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.

Serum translationally controlled tumor protein is involved in rat liver regeneration after hepatectomy

AIM

The translationally controlled tumor protein (TCTP) has been reported to promote progression of many physiological processes. However, whether TCTP is involved in liver regeneration has been rarely studied. This study aimed to investigate the potential role of serum TCTP in liver regeneration after two-thirds partial hepatectomy.

METHODS

The synthesis rate and accumulated expression of TCTP was assessed by phosphor imaging and Western blot analysis, respectively. The mRNA expression of tctp was analyzed by quantitative real-time PCR. The effect of serum TCTP on hepatocyte proliferation was investigated by bromodeoxyuridine incorporation, liver/body weight ratio, albumin concentration, and histological examination of liver following treatment of rat with anti-TCTP antibody or prokaryotic TCTP protein before hepatectomy. The MTT assay was used to examine effect of TCTP on hepatocyte proliferation in vitro.

RESULTS

The results showed that the expression of intracellular and serum TCTP protein was significantly increased in rats after two-thirds partial hepatectomy. In vivo bromodeoxyuridine labeling assay suggested that treatment with anti-TCTP antibody before hepatectomy significantly decreased hepatocyte proliferation and liver/body weight ratio. The prokaryotic TCTP had a potential promoting effect on hepatocyte proliferation both in vivo and in vitro, although prokaryotic TCTP given to rats prior to hepatectomy did not increase the proliferation ratio or liver/body weight ratio. Furthermore, anti-TCTP antibody pretreatment decreased the expression of cyclin E, cdk2, and interleukin-6 in rat liver.

CONCLUSION

These findings suggest serum TCTP is involved in rat liver regeneration through promoting hepatocyte proliferation.

Upregulated expression of substance P in basophils of the patients with chronic spontaneous urticaria: induction of histamine release and basophil accumulation by substance P

Human basophils have been implicated in the pathogenesis of chronic spontaneous urticaria (CSU), and substance P (SP) is a possible candidate as histamine-releasing factor in some patients with CSU. However, little is known of relationship between basophils and SP in CSU. In the present study, we investigated expression of SP and NK1R on basophils from patients with CSU, and influence of SP on basophil functions by using flow cytometry analysis, basophil challenge, and mouse sensitization model techniques. The results showed that plasma SP level and basophil numbers in CSU patients were higher than that in HC subject. The percentages of SP+ and NK1R+ basophils were markedly elevated in CSU blood in comparison with HC blood. Once added, SP induced up to 41.2 % net histamine release from basophils of CSU patients, which was comparable with that provoked by anti-IgE, and fMLP. It appeared that SP induced dramatic increase in blood basophil numbers of mice following peritoneal injection. Ovalbumin (OVA)-sensitized mice had much more SP+ and NK1R+ basophils in blood than non-sensitized mice. In conclusion, the elevated plasma concentration of SP, upregulated expression of SP and NK1R on basophils, and the ability of SP in induction of basophil degranulation and accumulation indicate strongly that SP is most likely a potent proinflammatory mediator, which contributes greatly to the pathogenesis of CSU through basophils. Inhibitors of SP and blockers of NK1R are likely useful agents for treatment of CSU.

Signaling and molecular basis of bone marrow niche angiogenesis in leukemia

Angiogenesis, the process of blood vessel formation, is necessary for tissue survival in normal and pathologic conditions. Increased angiogenesis in BM niche is correlated with leukemia progression and resistance to treatment. Angiogenesis can interfere with disease progression and several angiogenic (such as vascular growth factors) as well as anti-angiogenic factors (i.e. angiostatin) can affect angiogenesis. Furthermore, miRs can affect the angiogenic process by inhibiting angiogenesis or increasing the expression of growth factors. Given the importance of angiogenesis in BM for maintenance of leukemic clones, recognition of angiogenic and anti-angiogenic factors and miRs as well as drug resistance mechanisms of leukemic blasts can improve the therapeutic strategies. We highlight the changes in angiogenic balance within the BM niche in different leukemia types. Moreover, we explored the pathways leading to drug resistance in relation to angiogenesis and attempted to assign interesting candidates for future research.

Histamine-releasing factor/translationally controlled tumor protein plays a role in induced cell adhesion, apoptosis resistance and chemoresistance in non-Hodgkin lymphomas

Mounting evidence has proved that cellular adhesion confers resistance to chemotherapy in multiple lymphomas. The molecular mechanism underlying cell adhesion-mediated drug resistance (CAM-DR) is, however, poorly understood. In this study, we investigated the expression and biologic function of histamine-releasing factor (HRF) in non-Hodgkin lymphomas (NHLs). Clinically, by immunohistochemistry analysis we observed obvious up-regulation of HRF in NHLs including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and natural killer (NK)/T-cell lymphoma. Functionally, overexpression and knockdown of HRF demonstrated the antiapoptotic effect of HRF in NHL cells, which may be associated with activation of the p-CREB/BCL-2 signaling pathway. Moreover, cell adhesion assay demonstrated that adhesion to fibronectin (FN) or HS-5 up-regulated HRF expression, while knockdown of HRF resulted in decreased cell adhesion, which led to reversed CAM-DR. Our finding supports the role of HRF in NHL cell apoptosis, adhesion and drug resistance, and may provide a clinical therapeutic target for CAM-DR in NHL.