Testes-specific protease 50 (TSP50) promotes cell proliferation through the activation of the nuclear factor κB (NF-κB) signalling pathway

TSP50 facilitates breast cancer stem cell-like properties maintenance and epithelial-mesenchymal transition via PI3K p110α mediated activation of AKT signaling pathway

BACKGROUND

Studies have confirmed that epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC)-like properties are conducive to cancer metastasis. In recent years, testes-specific protease 50 (TSP50) has been identified as a prognostic factor and is involved in tumorigenesis regulation. However, the role and molecular mechanisms of TSP50 in EMT and CSC-like properties maintenance remain unclear.

METHODS

The expression and prognostic value of TSP50 in breast cancer were excavated from public databases and explored using bioinformatics analysis. Then the expression of TSP50 and related genes was further validated by quantitative RT-PCR (qRT-PCR), Western blot, and immunohistochemistry (IHC). In order to investigate the function of TSP50 in breast cancer, loss- and gain-of-function experiments were conducted, both in vitro and in vivo. Furthermore, immunofluorescence (IF) and immunoprecipitation (IP) assays were performed to explore the potential molecular mechanisms of TSP50. Finally, the correlation between the expression of TSP50 and related genes in breast cancer tissue microarray and clinicopathological characteristics was analyzed by IHC.

RESULTS

TSP50 was negatively correlated with the prognosis of patients with breast cancer. TSP50 promoted CSC-like traits and EMT in both breast cancer cells and mouse xenograft tumor tissues. Additionally, inhibition of PI3K/AKT partly reversed TSP50-induced activation of CSC-like properties, EMT and tumorigenesis. Mechanistically, TSP50 and PI3K p85α regulatory subunit could competitively interact with the PI3K p110α catalytic subunit to promote p110α enzymatic activity, thereby activating the PI3K/AKT signaling pathway for CSC-like phenotypes maintenance and EMT promotion. Moreover, IHC analysis of human breast cancer specimens revealed that TSP50 expression was positively correlated with p-AKT and ALDH1 protein levels. Notably, breast cancer clinicopathological characteristics, such as patient survival time, tumor size, Ki67, pathologic stage, N stage, estrogen receptor (ER) and progesterone receptor (PR) levels, correlated well with TSP50/p-AKT/ALDH1 expression status.

CONCLUSION

The effects of TSP50 on EMT and CSC-like properties promotion were verified to be dependent on PI3K p110α. Together, our study revealed a novel mechanism by which TSP50 facilitates the progression of breast cancer, which can provide new insights into TSP50-based breast cancer treatment strategies.

Expression of TSP50, SERCA2 and IL-8 in Colorectal Adenoma and Carcinoma: Correlation to Clinicopathological Factors

Background: Colorectal cancer (CRC) is the third most common type of cancer, it is considered a genetically heterogeneous disease with different molecular pathways being involved in its initiation and progression. Testes-specific protease 50 (TSP50) gene is a member of cancer/testis antigens that encodes for threonine protease enzyme. Overexpression of TSP50 was found to enhance the progression and invasion of breast cancer and other malignant tumors. SERCA2 is widely expressed in several body tissues; its aberrant expression has been involved in many cancers. IL-8 is an inflammatory cytokine. Alongside its role in inflammation, its expression was reported to induce the migration of tumor cells. Aim: Study the expression of TSP50, SERCA2 and IL-8 in colorectal adenoma (CRA), CRC and normal colonic tissues to compare the expression of these biomarkers in relation to clinicopathological parameters and prognostic factors. Results: TSP50, SERCA2 and IL-8 expression varied between normal colonic tissues, CRA and CRC. Significant statistical association was detected between the three biomarkers' overexpression and degree of dysplasia in CRA. Also, significant statistical relation was found between the three biomarkers' overexpression and presence of lympho-vascular invasion, advanced TNM staging and high intra-tumoral inflammatory infiltrate. Multivariable analysis showed that the overexpression of the three biomarkers is significantly associated with worse prognosis. Conclusion: The expression of TSP50, SERCA2 and IL-8 was different between the normal tissue and neoplastic colorectal tissue on one hand and between CRA and CRC on the other. Increased expression of these biomarkers in neoplastic epithelial cells of colorectal carcinoma is associated with adverse prognostic factors and could be considered as independent prognostic factors.

miR-3929 Inhibits Proliferation and Promotes Apoptosis by Downregulating Cripto-1 Expression in Cervical Cancer Cells

Cripto-1 is highly expressed in many cancers, and downregulating its expression may become a promising approach for cancer treatment. However, the regulation of Cripto-1 expression is not well characterized. In this study, we focused on the post-transcriptional regulation of Cripto-1 expression and analyzed the potential miRNAs that bind to the 3'UTR of Cripto-1 mRNA. miR-3929 was found to be able to bind to the 3'UTR and downregulate the expression of Cripto-1 in cervical cancer cells. Then, we analyzed the effect of miR-3929 on the biological behavior of cervical cancer cells, finding that miR-3929 could reduce cell viability, DNA synthesis, and Ki67 expression and induce cell cycle arrest in the G2/M phase; overexpression of Cripto-1 reversed the inhibitory effect of miR-3929 on proliferation. Moreover, DAPI staining and flow cytometry revealed that miR-3929-induced cell apoptosis is dependent on the mitochondrial pathway; the overexpression of Cripto-1 reversed the proapoptotic effect of miR-3929. Finally, the in vivo results showed that miR-3929 significantly inhibits the growth of HeLa xenograft tumors in nude mice. Therefore, our findings suggest that miR-3929 inhibits the proliferation and induces the apoptosis of cervical cancer cells by downregulating Cripto-1 via specifically targeting the 3'UTR of its mRNA.

Protease-triggered bioresponsive drug delivery for the targeted theranostics of malignancy

Proteases have a fundamental role in maintaining physiological homeostasis, but their dysregulation results in severe activity imbalance and pathological conditions, including cancer onset, progression, invasion, and metastasis. This striking importance plus superior biological recognition and catalytic performance of proteases, combining with the excellent physicochemical characteristics of nanomaterials, results in enzyme-activated nano-drug delivery systems (nanoDDS) that perform theranostic functions in highly specific response to the tumor phenotype stimulus. In the tutorial review, the key advances of protease-responsive nanoDDS in the specific diagnosis and targeted treatment for malignancies are emphatically classified according to the effector biomolecule types, on the premise of summarizing the structure and function of each protease. Subsequently, the incomplete matching and recognition between enzyme and substrate, structural design complexity, volume production, and toxicological issues related to the nanocomposites are highlighted to clarify the direction of efforts in nanotheranostics. This will facilitate the promotion of nanotechnology in the management of malignant tumors.

TSP50 promotes the Warburg effect and hepatocyte proliferation via regulating PKM2 acetylation

Metabolic reprogramming is a hallmark of malignancy. Testes-specific protease 50 (TSP50), a newly identified oncogene, has been shown to play an important role in tumorigenesis. However, its role in tumor cell metabolism remains unclear. To investigate this issue, LC-MS/MS was employed to identify TSP50-binding proteins and pyruvate kinase M2 isoform (PKM2), a known key enzyme of aerobic glycolysis, was identified as a novel binding partner of TSP50. Further studies suggested that TSP50 promoted aerobic glycolysis in HCC cells by maintaining low pyruvate kinase activity of the PKM2. Mechanistically, TSP50 promoted the Warburg effect by increasing PKM2 K433 acetylation level and PKM2 acetylation site (K433R) mutation remarkably abrogated the TSP50-induced aerobic glycolysis, cell proliferation in vitro and tumor formation in vivo. Our findings indicate that TSP50-mediated low PKM2 pyruvate kinase activity is an important determinant for Warburg effect in HCC cells and provide a mechanistic link between TSP50 and tumor metabolism.

PRSS50 is a testis protease responsible for proper sperm tail formation and function

Multiple morphological abnormalities of the sperm flagella (MMAF) are a major cause of asthenoteratozoospermia. We have identified protease serine 50 (PRSS50) as having a crucial role in sperm development, because Prss50-null mice presented with impaired fertility and sperm tail abnormalities. PRSS50 could also be involved in centrosome function because these mice showed a threefold increase in acephalic sperm (head-tail junction defect), sperm with multiple heads (spermatid division defect) and sperm with multiple tails, including novel two conjoined sperm (complete or partial parts of several flagellum on the same plasma membrane). Our data support that, in the testis, as in tumorigenesis, PRSS50 activates NFκB target genes, such as the centromere protein leucine-rich repeats and WD repeat domain-containing protein 1 (LRWD1), which is required for heterochromatin maintenance. Prss50-null testes have increased IκκB, and reduced LRWD1 and histone expression. Low levels of de-repressed histone markers, such as H3K9me3, in the Prss50-null mouse testis may cause increases in post-meiosis proteins, such as AKAP4, affecting sperm formation. We provide important insights into the complex mechanisms of sperm development, the importance of testis proteases in fertility and a novel mechanism for MMAF.

TSP50 promotes hepatocyte proliferation and tumour formation by activating glucose-6-phosphate dehydrogenase (G6PD)

Background & Aims

Hepatocellular carcinoma (HCC) is a common malignant tumour with high morbidity and mortality. Metabolic regulation by oncogenes is necessary for tumour growth. Testes‐specific protease 50 (TSP50) has been found to promote cell proliferation in multiple tumour types. However, the mechanism that TSP50 promotes HCC progression are not known.

Methods

Hepatocyte proliferation was analysed by MTT and BrdU incorporation after TSP50 transfection. Furthermore, LC‐MS/MS, co‐immunoprecipitation and GST pull‐down assays were performed to analyse protein(s) binding to TSP50. Moreover, the site‐specific mutation of G6PD was used to reveal the key site critical for G6PD acetylation mediated by TSP50. Finally, the role of G6PD K171 acetylation regulated by TSP50 in cell proliferation and tumour formation was investigated.

Results

Our data suggest that the overexpression of TSP50 accelerates hepatocyte proliferation. In addition, G6PD is an important protein that binds to TSP50 in the cytoplasm. TSP50 activates G6PD activity by inhibiting the acetylation of G6PD at the K171 site. In addition, TSP50 promotes the binding of G6PD to SIRT2. Furthermore, the K171ac of G6PD regulated by TSP50 is required for TSP50‐induced cell proliferation in vitro and tumour formation in vivo. Additionally, according to The Cancer Genome Atlas (TCGA) programme, TSP50 and G6PD are negatively correlated with the survival of HCC patients.

Conclusions

Collectively, our findings demonstrate that TSP50‐induced cell proliferation and tumour formation are mediated by G6PD K171 acetylation.

Ethyl-p-methoxycinnamate enhances oct4 expression and reinforces pluripotency through the NF-κB signaling pathway

Pluripotent stem cells are have therapeutic applications in regenerative medicine and drug discovery. However, the differentiation of stem cells in vitro hinders their large-scale production and clinical applications. The maintenance of cell pluripotency relies on a complex network of transcription factors; of these, octamer-binding transcription factor-4 (Oct4) plays a key role. This study aimed to construct an Oct4 gene promoter-driven firefly luciferase reporter and screen small-molecule compounds could maintain cell self-renewal and pluripotency. The results showed that ethyl-p-methoxycinnamate (EPMC) enhance the promoter activity of the Oct4 gene, increased the expression of Oct4 at both mRNA and protein levels, and significantly promoted the colony formation of P19 cells. These findings suggesting that EPMC could reinforce the self-renewal capacity of P19 cells. The pluripotency markers Oct4, SRY-related high-mobility-group-box protein-2, and Nanog were expressed at higher levels in EPMC-induced colonies. EPMC could promote teratoma formation and differentiation potential of P19 cells in vivo. It also enhanced self-renewal and pluripotency of human umbilical cord mesenchymal stem cells and mouse embryonic stem cells. Moreover, it significantly activated the nuclear factor kappa B (NF-κB) signaling pathway via the myeloid differentiation factor 88-dependent pathway. The expression level of Oct4 decreased after blocking the NF-κB signaling pathway, suggesting that EPMC promoted the expression of Oct4 partially through the NF-κB signaling pathway. This study indicated that EPMC could maintain self-renewal and pluripotency of stem cells.

Nitidine chloride induces S phase cell cycle arrest and mitochondria-dependent apoptosis in HaCaT cells and ameliorates skin lesions in psoriasis-like mouse models

Psoriasis is a common dermatosis causing considerable inconvenience to 4% of the general population. Traditional psoriasis treatments often cause side effects, drug resistance and complications, necessitating development of safer and more effective treatments. In this study, we screened over 600 natural compounds to identify viability inhibitors of human HaCaT keratinocytes cultured in vitro. The results showed that nitidine chloride was a highly effective inhibitor. Further studies revealed that nitidine chloride inhibited HaCaT proliferation and induced S phase cell cycle arrest; these effects were associated with reduced DNA synthesis, decreased Ki67, cyclin A, and cyclin D1 levels, and increased p53 protein expression. Nitidine chloride also significantly downregulated bcl-2 and upregulated bax, cleaved caspase-9 and cleaved caspase-3. Mechanistic studies revealed that nitidine chloride-induced apoptosis involved the c-Jun N-terminal kinase (JNK) pathway. More importantly, in 12-O-tetradecanoyl-phorbol-13-acetate (TPA)- and imiquimod (IMQ)-induced epidermal hyperplasia and inflammation models, nitidine chloride inhibited topical edema in mouse ear and back skin, substantially reducing tissue thickness and weight. In some cases, nitidine chloride also ameliorated conditions caused by TPA and IMQ, such as angiogenesis and infiltration of large numbers of inflammatory cells around blood vessels. Additionally, nitidine chloride inhibited the expression of various proinflammatory cytokines in the two animal models. In conclusion, our results are the first to demonstrate that nitidine chloride inhibits the proliferation of HaCaT cells, induces apoptosis partly via the JNK signaling pathway in vitro and ameliorates skin lesions and inflammation in vivo, making it an appropriate candidate for psoriasis treatment.

Expression and effects of TSP50 in mouse embryo and cardiac myocyte development

TSP50, a testis-specific gene encoding a serine protease-like protein, was specifically expressed in the spermatocytes of testes but abnormally activated and expressed in many different kinds of cancers. Here, we aimed to analyze the expression of TSP50 in mouse embryo and its function in early embryonic development. Firstly, the distribution of TSP50 in oocytes and embryonic development was characterized by immunofluorescence, RT-PCR and western blotting, and the results showed that TSP50 was detected at all studied stages with a dynamic expression pattern. When overexpressed TSP50 in zygotes by microinjection, the zygotes development was highly accelerated. On the contrary, knocking down TSP50 expression by RNA interference greatly retarded the zygote development. Furthermore, TSP50 expression at embryonic day 6.5 (E6.5), day 8.5 (E8.5) and day 10.5 (E10.5) were increasingly enhanced, However, the expression of TSP50 decreased gradually in the development and differentiation of cardiac myocyte from E12.5 to postnatal (P0). Additionally, we found that TSP50 expression was decreased during cardiac myocyte differentiation of P19 cells. Overexpression of TSP50 could decrease the expression of GATA-4, and knockdown of TSP50 markedly increase the expression of GATA-4. Taken together, our data indicate that TSP50 may play an important role during the process of mouse embryonic development as well as myocardial cell differentiation.

Cripto-1 promotes resistance to drug-induced apoptosis by activating the TAK-1/NF-κB/survivin signaling pathway

Cripto-1 is an oncogenic protein that belongs to the epidermal growth factor (EGF)-cripto-1/FRL1/cryptic (CFC) family. It has been shown to stimulate tumorigenesis and metastasis by promoting cancer cell proliferation, epithelial-to-mesenchymal transition (EMT), and tumor angiogenesis. However, the role of Cripto-1 in cell survival and apoptosis remains largely undefined. In the present study, we found that Cripto-1 is significantly upregulated in a number of human cancer cell lines. The membrane-associated but not the soluble form of Cripto-1 promotes resistance to drug-induced caspase-3 cleavage, an indicator of apoptosis. Consequently, Cripto-1 silencing sensitizes human cancer cells to chemotherapy drugs including cytarabine, cisplatin and taxol. Our mechanistic studies revealed that Cripto-1 promotes apoptosis resistance by inducing NF-κB-mediated Survivin expression through activation of TAK-1. We also found that Cripto-1 silencing does not affect growth of un-treated cancer cells, and Cripto-1 forms self-assembled punctiforms and changes its subcellular distribution upon cytarabine treatment. Thus, the anti-apoptotic activity of Cripto-1 could be an inducible function that can be activated by external stimuli such as drug stimulation. Our findings suggested that targeting the Cripto-1/TAK-1/NF-κB/Survivin pathway may be an effective approach to combat apoptosis resistance in cancer.

Cardamonin reduces chemotherapy resistance of colon cancer cells via the TSP50/NF-κB pathway in vitro

It has previously been reported that cardamonin is able to regulate glycometabolism and vasodilation whilst also exhibiting anti-inflammatory and antitumor properties. The antitumor effect of cardamonin is multifaceted, and so it is necessary to investigate the antitumor mechanisms of cardamonin at the molecular level. Cardamonin alters chemotherapy-resistant colon cancer cell growth; however, the underlying mechanism is unknown. The present study was conducted to investigate the effect of cardamonin on chemotherapy-resistant colon cancer cells and the possible mechanisms of action. Cardamonin significantly suppressed the growth of chemotherapy-resistant colon cancer cells, induced apoptosis and promoted caspase-3/9 activity and Bax protein expression in 5-fluorouracil (5-FU)-resistant HCT-116 cells. Cardamonin significantly suppressed c-MYC, octamer-binding transcription factor 4, cyclin E, testes-specific protease 50 and nuclear factor-κB protein expression in 5-FU-resistant HCT-116 cells. The findings of the present study demonstrate that cardamonin suppresses chemotherapy-colon cancer cell via the NF-κB pathway in vitro.

Testes-specific protease 50 as an independent risk factor for poor prognosis in patients with non-small cell lung cancer

Testes-specific protease 50 (TSP50) is normally expressed in the testes and is overexpressed in various types of human cancers, including breast cancer, colorectal carcinoma and laryngocarcinoma. However, little has been reported on the association between TSP50 and non-small cell lung cancer (NSCLC). The present study aimed to detect TSP50 expression in 198 strict follow-up cases of paired NSCLC and 15 cases of normal lung parenchymal specimens using immunohistochemical staining. The expression levels of TSP50 were then correlated with the clinicopathological factors of NSCLC to assess its potential diagnostic and prognostic value. The relationship between TSP50 expression and the clinicopathological parameters of NSCLC was evaluated using χ² and Fisher's exact tests. Survival rates for the overall population (n=198) were calculated using the Kaplan-Meier method, and univariate and multivariate analyses were performed using the Cox's proportional hazards regression model. P<0.05 was considered to indicate a statistically significant difference. The expression of TSP50 was significantly increased in NSCLC tissue compared with in adjacent non-tumor or normal lung parenchymal tissue (P<0.001). A significant association was revealed between high expression levels of TSP50 and clinicopathological characteristics including tumor differentiation (P=0.012), late tumor status (P=0.004) and late tumor node metastasis stage (P=0.026), as well as a reduced disease free survival (P=0.009) and overall survival rate (P=0.002) in all patients with NSCLC. Multivariate analyses demonstrated that high TSP50 expression in tumor tissues was significantly associated with a shorter disease-free survival rate [hazard ratio (HR) =1.590, 95% confidence interval (CI): 1.035-2.441], and with a shorter overall survival rate (HR=1.814; 95% CI: 1.156-2.846). In conclusion, the present data demonstrated that increased TSP50 protein expression may be a potential predictor of early recurrence and poor prognosis in NSCLC, and that TSP50 expression levels possess the potential to be used as a biomarker and therapeutic target for the treatment of patients with NSCLC.

Testes-specific protease 50 (TSP50) promotes invasion and metastasis by inducing EMT in gastric cancer

Background

TSP50 (testes-specific protease 50) has been reported to be a candidate oncogene and is overexpressed in various cancers. Our previous study demonstrated that TSP50 protein is elevated in gastric cancer, and its high expression is associated with unfavorable prognosis and lymph node metastasis. However, the role of TSP50 in gastric cancer remains elusive.

Methods

qRT-PCR, western blot were used to determine TSP50 expression in gastric cancer cell lines. Role of TSP50 in proliferation and invasion was examined by BrdU incorporation assay, cell count, wound healing and transwell assay. Immunohistochemistry and western blot were performed to identify the potential mechanisms involved.

Results

TSP50 was highly expressed in most of the gastric cancer cell lines at both mRNA and protein levels. Up-regulation of TSP50 in gastric cancer cells enhanced proliferation and invasiveness, whereas down-regulation of TSP50 by its specific shRNA decreased it. A negative correlation between TSP50 and E-Cadherin was found in gastric cancer tissues, and combination of them improves the prediction for prognosis and lymph node metastasis. Mechanistic studies revealed that overexpression of TSP50 increased the expression of epithelial-to-mesenchymal transition (EMT) markers including Vimentin, and Twist, and decreased the epithelial marker E-Cadherin. NF-κB signaling pathway is involved in the regulatory effects of TSP50 on EMT, migration and invasion in gastric cancer cells.

Conclusion

TSP50 promotes the proliferation, migration and invasion of gastric cancer cells involving NF-κB dependent EMT activation. Targeting TSP50 may provide a novel therapeutic strategy for the management of gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4000-y) contains supplementary material, which is available to authorized users.

NLRP3 inflammasome activation contributes to VSMC phenotypic transformation and proliferation in hypertension

Inflammation is involved in pathogenesis of hypertension. NLRP3 inflammasome activation is a powerful mediator of inflammatory response via caspase-1 activation. The present study was designed to determine the roles and mechanisms of NLRP3 inflammasome in phenotypic modulation and proliferation of vascular smooth muscle cells (VSMCs) in hypertension. Experiments were conducted in spontaneously hypertensive rats (SHR) and primary aortic VSMCs. NLRP3 inflammasome activation was observed in the media of aorta in SHR and in the VSMCs from SHR. Knockdown of NLRP3 inhibited inflammasome activation, VSMC phenotypic transformation and proliferation in SHR-derived VSMCs. Increased NFκB activation, histone acetylation and histone acetyltransferase expression were observed in SHR-derived VSMCs and in media of aorta in SHR. Chromatin immunoprecipitation analysis revealed the increased histone acetylation, p65-NFκB and Pol II occupancy at the NLRP3 promoter in vivo and in vitro. Inhibition of NFκB with BAY11-7082 or inhibition of histone acetyltransferase with curcumin prevented the NLRP3 inflammasome activation, VSMC phenotype switching and proliferation in VSMCs from SHR. Moreover, curcumin repressed NFκB activation. Silencing of NLRP3 gene ameliorated hypertension, vascular remodeling, NLRP3 inflammasome activation and phenotype switching in the aorta of SHR. These results indicate that NLRP3 inflammasome activation response to histone acetylation and NFκB activation contributes to VSMC phenotype switching and proliferation and vascular remodeling in hypertension.

Testes-specific protease 50 promotes cell proliferation via inhibiting activin signaling

Testes-specific protease 50 (TSP50), a novelly identified oncogene, has the capacity to induce cell proliferation, cell invasion and tumor growth. Further studies indicated that CAGA-luc (an activin-responsive reporter construct) reporter activity could be significantly suppressed by TSP50 overexpression, implying that the activin signaling may participate in TSP50-mediated cell proliferation. Here, we reported that TSP50 had an inhibitory effect on activin signaling. Mechanistic studies revealed that TSP50 could interact with ActRIIA, inhibit activin typeIreceptor (ActRIB) phosphorylation, repress Smad2/3 nuclear accumulation and finally promote cell proliferation by reducing the expression of activin signal target gene p27. Additionally, we found that ActRIB activation could reverse TSP50-mediated cell proliferation and tumor growth. Furthermore, analysis of human breast cancer specimens by immunohistochemistry indicated that TSP50 expression was negatively related to p-Smad2/3 and p27 protein levels. Most importantly, breast cancer diagnosis-related indicators such as tumor size, tumor grade, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) levels, were correlated well with TSP50/p-Samd2/3 and TSP50/p27 expression status. Thus, our studies revealed a novel regulatory mechanism underlying TSP50-induced cell proliferation and provided a new favorable intervention target for the treatment of breast cancer.

Roles of cancer/testis antigens (CTAs) in breast cancer

Breast cancer is the most common cancer diagnosed and is the second leading cause of cancer death among women in the US. For breast cancer, early diagnosis and efficient therapy remains a significant clinical challenge. Therefore, it is necessary to identify novel tumor associated molecules to target for biomarker development and immunotherapy. In this regard, cancer testis antigens (CTAs) have emerged as a potential clinical biomarker targeting immunotherapy for various malignancies due to the nature of its characteristics. CTAs are a group of tumor associated antigens (TAAs) that display normal expression in immune-privileged organs, but display aberrant expression in several types of cancers, particularly in advanced cancers. Investigation of CTAs for the clinical management of breast malignancies indicates that these TAAs have potential roles as novel biomarkers, with increased specificity and sensitivity compared to those currently used in the clinic. Moreover, TAAs could be therapeutic targets for cancer immunotherapy. This review is an attempt to address the promising CTAs in breast cancer and their possible clinical implications as biomarkers and immunotherapeutic targets with particular focus on challenges and future interventions.

Protumoral TSP50 Regulates Macrophage Activities and Polarization via Production of TNF-α and IL-1β, and Activation of the NF-κB Signaling Pathway

Testes-specific protease 50 (TSP50) is abnormally overexpressed in many kinds of cancers and promotes cell proliferation and migration. However, whether TSP50 can influence the tumor microenvironment, especially the function of immune cells in the microenvironment, remains largely unknown. We demonstrated that exposure to the conditioned medium from TSP50-overexpressing cells, or co-culture with TSP50-overexpressing cells, enhanced the cytokine production and phagocytic activities of macrophages, and induced M2b polarization. Further investigation showed that production of TNF-α and IL-1β was strongly induced by TSP50 in TSP50-overexpressing cells. TSP50-induced TNF-α and IL-1β were main factors that mediated the effects of TSP50-overexpressing cells on macrophages. The NF-κB pathway could be activated in macrophages upon the treatment of conditioned medium of TSP50-overexpressing cells and its activation is necessary for the observed effects on macrophages. Taken together, our results suggested that oncogenic TSP50 expressed in cells could activate surrounding macrophages and induce M2b polarization, partly through inducing TNF-α/ IL-1β secretion and subsequent NF-κB pathway activation. This implies a potential mechanism by which oncogene TSP50 regulates tumor microenvironment to support tumor development.

Juglanthraquinone C Induces Intracellular ROS Increase and Apoptosis by Activating the Akt/Foxo Signal Pathway in HCC Cells

Juglanthraquinone C (JC), a naturally occurring anthraquinone extracted from Juglans mandshurica, could induce apoptosis of cancer cells. This study aims to investigate the detailed cytotoxicity mechanism of JC in HepG2 and BEL-7402 cells. The Affymetrix HG-U133 Plus 2.0 arrays were first used to analyze the mRNA expression exposed to JC or DMSO in HepG2 cells. Consistent with the previous results, the data indicated that JC could induce apoptosis and hyperactivated Akt. The Western blot analysis further revealed that Akt, a well-known survival protein, was strongly activated in HepG2 and BEL-7402 cells. Furthermore, an obvious inhibitory effect on JC-induced apoptosis was observed when the Akt levels were decreased, while the overexpression of constitutively active mutant Akt greatly accelerated JC-induced apoptosis. The subsequent results suggested that JC treatment suppressed nuclear localization and increased phosphorylated levels of Foxo3a, and the overexpression of Foxo3a abrogated JC-induced apoptosis. Most importantly, the inactivation of Foxo3a induced by JC further led to an increase of intracellular ROS levels by suppressing ROS scavenging enzymes, and the antioxidant N-acetyl-L-cysteine and catalase successfully decreased JC-induced apoptosis. Collectively, this study demonstrated that JC induced the apoptosis of hepatocellular carcinoma (HCC) cells by activating Akt/Foxo signaling pathway and increasing intracellular ROS levels.

TSP50 depends on its threonine protease activity and its interactions with TNF-α-induced NF-κB for its role in human cervical tumorigenesis

Testes-specific protease 50 (TSP50) has threonine activity and has homology to serine proteases. TSP50 protein, which is encoded by a possible proto-oncogene, is overexpressed in cervical tumor tissues. Through overexpression experiments using both TSP50 and a TSP50 mutant (TSP50 T310A), it is clear that this protein may play an important role in carcinogenesis and progression of cervical tumor. However, the mechanism underlying how TSP50 modulates cancer cell growth is still unclear. To examine the difference in TSP50 expression in cervical carcinoma tissues and in paracarcinoma tissues, we detected TSP50 mRNA and protein in ten paired tissues from patients with cervical cancer. To determine whether TSP50's threonine protease activity is crucial for its effects on tumor formation, we generated a mutant version of TSP50 (T310A). Via overexpression and silencing experiments, we identified a role for TSP50 in cell proliferation and migration. Furthermore, we examined the signaling pathway of TNF-α-induced NFκB activation to explain the mechanism by which TSP50 participates in tumorigenesis. Similarly, we found that all these effects could be abolished by the TSP50 T310A mutation. Our results suggest that the threonine 310 residue within TSP50 helps modulate its role in cervical tumorigenesis and indicates that TSP50's role in tumorigenesis may be dependent on its interaction with TNF-α-induced NF-κB.

Testes-specific protease 50 promotes cell invasion and metastasis by increasing NF-kappaB-dependent matrix metalloproteinase-9 expression

The high mortality in breast cancer is often associated with metastatic progression in patients. Previously we have demonstrated that testes-specific protease 50 (TSP50), an oncogene overexpressed in breast cancer samples, could promote cell proliferation and tumorigenesis. However, whether TSP50 also has a key role in cell invasion and cancer metastasis, and the mechanism underlying the process are still unclear. Here we found that TSP50 overexpression greatly promoted cell migration, invasion, adhesion and formation of the stellate structures in 3D culture system in vitro as well as lung metastasis in vivo. Conversely, TSP50 knockdown caused the opposite changes. Mechanistic studies revealed that NF-κB signaling pathway was required for TSP50-induced cell migration and metastasis, and further results indicated that TSP50 overexpression enhanced expression and secretion of MMP9, a target gene of NF-κB signaling. In addition, knockdown of MMP9 resulted in inhibition of cell migration and invasion in vitro and lung metastasis in vivo. Most importantly, immunohistochemical staining of human breast cancer samples strongly showed that the coexpression of TSP50 and p65 as well as TSP50 and MMP9 were correlated with increased metastasis and poor survival. Furthermore, we found that some breast cancer diagnosis-associated features such as tumor size, tumor grade, estrogen receptors (ER) and progesterone receptors (PR) levels, were correlated well with TSP50/p65 and TSP50/MMP9 expression status. Taken together, this work identified the TSP50 activation of MMP9 as a novel signaling mechanism underlying human breast cancer invasion and metastasis.

Down-regulation of testes-specific protease 50 induces apoptosis in human laryngocarcinoma HEp2 cells in a NF-κB-mediated pathway

Testes-specific protease 50 is a newly reported threonine enzyme. It has similar amino acid sequences and enzymatic structures to some other serine proteases. It is proposed as a laryngocarcinoma-related gene in human beings. The physiological mechanism by which TSP50 exerts its promoting effects in laryngocarcinoma is not yet fully understood. The study investigated the function of TSP50 by suppressing its expression in the HEp2 cell line using a TSP50-specific short hairpin RNA (shRNA). Western bloting and real-time-PCR were used to detect the levels of TSP50. By using MTT, Wound healing, flow cytometric and tumorigenesis assays, the study tested the TSP50 role in human laryngocarcinoma cell growth and apoptosis. The results demonstrated that TSP50 knockdown could inhibit HEp2 cell proliferation and induce apoptosis in vitro in a NF-κB-mediated pathway. The tumorigenicity of TSP50 shRNA-expressing cells were decreased after inoculating into nude mice. The present results provide a new understanding of the TSP50 gene in the progression of laryngocarcinoma and put up a novel therapeutic target for treating this cancer.

Depression of testes-specific protease 50 (TSP50) inhibits cell proliferation and induces apoptosis in laryngocarcinoma

Testes-specific protease 50 (TSP50) is a potential cancer-associated gene that may be involved in human laryngocarcinoma. The present study aimed to investigate suppressive effects on the HEp2 human laryngocarcinoma cell line by transfection with TSP50-specific short hairpin RNA (shRNA). Western blot analysis was used to detect the expression levels of TSP50. MTT assay was used to evaluate cell proliferation. Wound healing was used in cell migration and invasion assays to evaluate the cell exercise capacity. Nuclear staining assay was used to evaluate cell apoptosis after knockdown of TSP50. Expression levels of TSP50 protein in the shRNA group were downregulated successfully by transfection, and the knockdown of endogenous TSP50 in HEp2 cells greatly inhibited nuclear factor κB (NF-κB) activity. MTT results showed that the cell proliferation in the shRNA group was significantly more depressed than that in the blank (P < 0.05) and negative control groups (P < 0.05). Additionally, a decreased number of migrated cells in the shRNA group was observed (P < 0.05) using a cell migration and invasion assay. Moreover, knockdown of endogenous TSP50 expression can induce apoptosis in HEp2 Cells. These data indicated that knockdown of TSP50 may cause inhibition of proliferation, migration, and invasion of HEp2 cells. This study provides a new perspective in understanding the molecular mechanisms underlying the progression of laryngocarcinoma and offers a potential therapeutic target for laryngocarcinoma.

The catalytic triad of testes-specific protease 50 (TSP50) is essential for its function in cell proliferation

Testes-specific protease 50 (TSP50) is a novelly identified pro-oncogene and it shares a similar enzymatic structure with many serine proteases. Our previous results suggested that TSP50 could promote tumorigenesis through degradation of IκBα protein and activating NF-κB signaling, and the threonine mutation in its catalytic triad could depress TSP50-mediated cell proliferation. However, whether the two other residues in the catalytic triad of TSP50 play a role in maintaining protease activity and tumorigenesis, and the mechanisms involved in this process remain unclear. Here, we constructed and characterized three catalytic triad mutants of TSP50 and found that all the mutants could significantly depress TSP50-induced cell proliferation and colony formation in vitro and tumor formation in vivo, and the aspartic acid at position 206 in the catalytic triad played a more crucial role than threonine and histidine in this process. Mechanistic studies revealed that the mutants in the catalytic triad abolished the enzyme activity of TSP50, but did not change the cellular localization. Furthermore, our data indicated that all the three mutants suppressed activation of NF-κB signal by preventing the interaction between TSP50 and the NF-κB:IκBα complex. Most importantly, we demonstrated that TSP50 could interact with IκBα protein and cleave it directly as a new protease in vitro.

Overexpression of Testes-Specific Protease 50 (TSP50) Predicts Poor Prognosis in Patients with Gastric Cancer

Purpose. To investigate the expression of TSP50 protein in human gastric cancers and its correlation with clinical/prognostic significance. Methods. Immunohistochemistry (IHC) analysis of TSP50 was performed on a tissue microarray (TMA) containing 334 primary gastric cancers. Western blot was carried out to confirm the expression of TSP50 in gastric cancers. Results. IHC analysis revealed high expression of TSP50 in 57.2% human gastric cancer samples (191 out of 334). However, it was poorly expressed in all of the 20 adjacent nontumor tissues. This was confirmed by western blot, which showed significantly higher levels of TSP50 expression in gastric cancer tissues than adjacent nontumor tissues. A significant association was found between high levels of TSP50 and clinicopathological characteristics including junior age at surgery (P = 0.001), later TNM stage (P = 0.000), and present lymph node metastases (P = 0.003). The survival of gastric cancer patients with high expression of TSP50 was significantly shorter than that of the patients with low levels of TSP50 (P = 0.021). Multivariate Cox regression analysis indicated that TSP50 overexpression was an independent prognostic factor for gastric cancer patients (P = 0.017). Conclusions. Our data demonstrate that elevated TSP50 protein expression could be a potential predictor of poor prognosis in gastric cancer patients.

Alantolactone induces cell apoptosis partially through down-regulation of testes-specific protease 50 expression

Testes-specific protease 50 (TSP50) is aberrantly expressed in many cancer biopsies and plays a crucial role in tumorigenesis, which make it a potential cancer therapeutic target for drug discovery. Here, we constructed a firefly luciferase reporter driven by the TSP50 gene promoter to screen natural compounds capable of inhibiting the expression of TSP50. Then we identified alantolactone, a sesquiterpene lactone, could efficiently inhibit the promoter activity of TSP50 gene, further results revealed that alantolactone also efficiently inhibited the expression of TSP50 in both mRNA and protein levels. Moreover, we found alantolactone could increase the ratio of Bax/Bcl-2, and activate caspase-9 and caspase-3 in the cancer cells with high expression of TSP50, surprisingly, the same effects can also be observed in the same cells just by knockdown of TSP50 gene expression. Furthermore, our results suggested that overexpression of TSP50 decreased the cell sensitivity to alantolactone-induced apoptosis in those cancer cells. Taken together, these results suggest that alantolactone induces mitochondrial-dependent apoptosis at least partially via down-regulation of TSP50 expression.

Cancer testes antigens in breast cancer: biological role, regulation, and therapeutic applicability

Breast cancer remains one of the leading causes of death among women across the world. The last few decades have seen significant reduction in mortality owing to earlier detection and better adjuvant treatments that were developed based on clinical staging and morphological features. As these treatments have evolved, the heterogeneity of breast cancer poses a new challenge, since there is no standard gold-therapy suitable for all tumors of the mammary gland. Therefore, contemporary management and research efforts are directed toward specific prognostic and predictive molecular signatures that can guide targeted individualized therapy. The goal of ongoing research in this field is to identify specific molecular targets for developing novel therapeutic approaches. These targets can also serve to improve screening of breast cancer. This review focuses on the role of cancer testis antigens (CTAs) in breast carcinogenesis and explores the potential for development of targeted screening and therapeutic approaches. Normally found in the testes, these antigens are highly correlative with cancers of the breast, skin, and ovaries. These implications have been further corroborated through uncovering the interaction of CTAs with genes and proteins involved in tumor suppression and homeostasis like p53. There is some evidence that these genes can be targeted for early detection in addition to being candidates for cancer immunotherapy.

Parental exposure to natural mixtures of POPs reduced embryo production and altered gene transcription in zebrafish embryos

Determination of toxicity of complex mixtures has been proposed to be one of the most important challenges for modern toxicology. In this study we performed genome wide transcriptome profiling to assess potential toxicant induced changes in gene regulation in zebrafish embryos following parental exposure to two natural mixtures of persistent organic pollutants (POPs). The mixtures used were extracted from burbot (Lota lota) liver originating from two lakes (Lake Mjøsa and Lake Losna) belonging to the same freshwater system in Norway. The dominating groups of contaminants were polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane metabolites (DDTs). Because both mixtures used in the present study induced similar effects, it is likely that the same toxicants are involved. The Mjøsa mixture contains high levels of PBDEs while this group of pollutants is low in the Losna mixture. However, both mixtures contain substantial concentrations of PCB and DDT suggesting these contaminants as the predominant contributors to the toxicity observed. The observed effects included phenotypic traits, like embryo production and survival, and gene transcription changes corresponding with disease and biological functions such as cancer, reproductive system disease, cardiovascular disease, lipid and protein metabolism, small molecule biochemistry and cell cycle. The changes in gene transcription included genes regulated by HNF4A, insulin, LH, FSH and NF-κB which are known to be central regulators of endocrine signaling, metabolism, metabolic homeostasis, immune functions, cancer development and reproduction. The results suggest that relative low concentrations of the natural mixtures of POPs used in the present study might pose a threat to wild freshwater fish living in the lakes from which the POPs mixtures originated.

The threonine protease activity of testes-specific protease 50 (TSP50) is essential for its function in cell proliferation

BACKGROUND

Testes-specific protease 50 (TSP50), a newly discovered threonine enzyme, has similar amino acid sequences and enzymatic structures to those of many serine proteases. It may be an oncogene. TSP50 is up-regulated in breast cancer epithelial cells, and ectopic expression of TSP50 in TSP50-deficient Chinese hamster ovary (CHO) cells has been found to promote cell proliferation. However, the mechanisms by which TSP50 exerts its growth-promoting effects are not yet fully understood.

METHODOLOGY/PRINCIPAL FINDINGS

To delineate whether the threonine protease activity of TSP50 is essential to its function in cell proliferation, we constructed and characterized a mutant TSP50, called TSP50 T310A, which was identified as a protease-dead mutant of TSP50. By a series of proliferation analyses, colony formation assays and apoptosis analyses, we showed that T310A mutation significantly depresses TSP50-induced cell proliferation in vitro. Next, the CHO stable cell line expressing either wild-type or T310A mutant TSP50 was injected subcutaneously into nude mice. We found that the T310A mutation could abolish the tumorigenicity of TSP50 in vivo. A mechanism investigation revealed that the T310A mutation prevented interaction between TSP50 and the NF-κBIκBα complex, which is necessary for TSP50 to perform its function in cell proliferation.

CONCLUSION

Our data highlight the importance of threonine 310, the most critical protease catalytic site in TSP50, to TSP50-induced cell proliferation and tumor formation.

High expression of testes-specific protease 50 is associated with poor prognosis in colorectal carcinoma

Background

Testes-specific protease 50 (TSP50) is normally expressed in testes and abnormally expressed in breast cancer, but whether TSP50 is expressed in colorectal carcinoma (CRC) and its clinical significance is unclear. We aimed to detect TSP50 expression in CRC, correlate it with clinicopathological factors, and assess its potential diagnostic and prognostic value.

Methodology/Principal Findings

TSP50 mRNAs and proteins were detected in 7 CRC cell lines and 8 CRC specimens via RT-PCR and Western blot analysis. Immunohistochemical analysis of TSP50, p53 and carcinoembryonic antigen (CEA) with tissue microarrays composed of 95 CRCs, 20 colorectal adenomas and 20 normal colorectal tissues were carried out and correlated with clinicopathological characteristics and disease-specific survival for CRC patients. There was no significant correlation between the expression levels of TSP50 and p53 (P = 0.751) or CEA (P = 0.663). Abundant expression of TSP50 protein was found in CRCs (68.4%) while it was poorly expressed in colorectal adenomas and normal tissues (P<0.0001). Thus, CRCs can be distinguished from them with high specificity (92.5%) and positive predictive value (PPV, 95.6%). The survival of CRC patients with high TSP50 expression was significantly shorter than that of the patients with low TSP50 expression (P = 0.010), specifically in patients who had early-stage tumors (stage I and II; P = 0.004). Multivariate Cox regression analysis indicated that high TSP50 expression was a statistically significant independent risk factor (hazard ratio  = 2.205, 95% CI = 1.214–4.004, P = 0.009).

Conclusion

Our data demonstrate that TSP50 is a potential effective indicator of poor survival for CRC patients, especially for those with early-stage tumors.