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

TSP50 Attenuates DSS-Induced Colitis by Regulating TGF-β Signaling Mediated Maintenance of Intestinal Mucosal Barrier Integrity

The integrity of the intestinal mucosal barrier is crucial for protecting the intestinal epithelium against invasion by commensal bacteria and pathogens, thereby combating colitis. The investigation revealed that the absence of TSP50 compromised the integrity of the intestinal mucosal barrier in murine subjects. This disruption facilitated direct contact between intestinal bacteria and the intestinal epithelium, thereby increasing susceptibility to colitis. Mechanistic analysis indicated that TSP50 deficiency in intestinal stem cells (ISCs) triggered aberrant activation of the TGF-β signaling pathway and impeded the differentiation of goblet cells in mice, leading to impairment of mucosal permeability. By inhibiting the TGF-β pathway, the functionality of the intestinal mucosal barrier is successfully restored and mitigated colitis in TSP50-deficient mice. In conclusion, TSP50 played a crucial role in maintaining the intestinal mucosal barrier function and exhibited the preventive effect against the development of colitis by regulating the TGF-β signaling pathway.

Safety and Activity of PolyPEPI1018 Combined with Maintenance Therapy in Metastatic Colorectal Cancer: an Open-Label, Multicenter, Phase Ib Study

PURPOSE

Although chemotherapy is standard of care for metastatic colorectal cancer (mCRC), immunotherapy has no role in microsatellite stable (MSS) mCRC, a "cold" tumor. PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine derived from 7 tumor-associated antigens (TAA) frequently expressed in mCRC. This study assessed PolyPEPI1018 combined with first-line maintenance therapy in patients with MSS mCRC.

PATIENTS AND METHODS

Eleven patients with MSS mCRC received PolyPEPI1018 and Montanide ISA51VG adjuvant subcutaneously, combined with fluoropyrimidine/biologic following first-line induction with chemotherapy and a biologic (NCT03391232). In Part A of the study, 5 patients received a single dose; in Part B, 6 patients received up to three doses of PolyPEPI1018 every 12 weeks. The primary objective was safety; secondary objectives were preliminary efficacy, immunogenicity at peripheral and tumor level, and immune correlates.

RESULTS

PolyPEPI1018 vaccination was safe and well tolerated. No vaccine-related serious adverse event occurred. Eighty percent of patients had CD8+ T-cell responses against ≥3 TAAs. Increased density of tumor-infiltrating lymphocytes were detected post-treatment for 3 of 4 patients' liver biopsies, combined with increased expression of immune-related gene signatures. Three patients had objective response according to RECISTv1.1, and 2 patients qualified for curative surgery. Longer median progression-free survival for patients receiving multiple doses compared with a single dose (12.5 vs. 4.6 months; P = 0.017) suggested a dose-efficacy correlation. The host HLA genotype predicted multi-antigen-specific T-cell responses (P = 0.01) indicative of clinical outcome.

CONCLUSIONS

PolyPEPI1018 added to maintenance chemotherapy for patients with unresectable, MSS mCRC was safe and associated with specific immune responses and antitumor activity warranting further confirmation in a randomized, controlled setting.

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.

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.

A qualitative transcriptional signature for the early diagnosis of colorectal cancer

Currently, using biopsy specimens for the early diagnosis of colorectal cancer (CRC) is not entirely reliable due to insufficient sampling amount and inaccurate sampling location. Thus, it is necessary to develop a signature that can accurately identify patients with CRC under these clinical scenarios. Based on the relative expression orderings of genes within individual samples, we developed a qualitative transcriptional signature to discriminate CRC tissues, including CRC adjacent normal tissues from non-CRC individuals. The signature was validated using multiple microarray and RNA sequencing data from different sources. In the training data, a signature consisting of 7 gene pairs was identified. It was well validated in both biopsy and surgical resection specimens from multiple datasets measured by different platforms. For biopsy specimens, 97.6% of 42 CRC tissues and 94.5% of 163 non-CRC (normal or inflammatory bowel disease) tissues were correctly classified. For surgically resected specimens, 99.5% of 854 CRC tissues and 96.3% of 81 CRC adjacent normal tissues were correctly identified as CRC. Notably, we additionally measured 33 CRC biopsy specimens by the Affymetrix platform and 13 CRC surgical resection specimens, with different proportions of tumor epithelial cells, ranging from 40% to 100%, by the RNA sequencing platform, and all these samples were correctly identified as CRC. The signature can be used for the early diagnosis of CRC, which is also suitable for minimum biopsy specimens and inaccurately sampled specimens, and thus has potential value for clinical application.

The potential immune-eliciting cancer testis antigens in colorectal cancer

The identification of cancer testis antigens (CTAs) has been an important finding in the search of potential targets for cancer immunotherapy. CTA is one of the subfamilies of the large tumor-associated antigens groups. It is aberrantly expressed in various types of human tumors but is absent in normal tissues except for the testis and placenta. This CTAs-restricted pattern of expression in human malignancies together with its potential immunogenic properties, has stirred the interest of many researchers to use CTAs as one of the ideal targets in cancer immunotherapy. To date, multiple studies have shown that CTAs-based vaccines can elicit clinical and immunological responses in different tumors, including colorectal cancer (CRC). This review details our current understanding of CTAs and CRC in regard to the expression and immunological responses as well as some of the critical hurdles in CTAs-based immunotherapy.

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.

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.

[Cancer-testis genes in colon cancer]

The expression of cancer-testis (CT) genes varies with tumor type. There are tumors with high, low, and intermediate gene expressions. Tumor cells of different origin are characterized by ST gene co-expression. The expression of ST genes increases in later stages of tumor development in the presence of metastases. In colon cancer, the tumor samples showed most frequently MAGE-A and SSX mRNA. The peripheral blood samples displayed most commonly XAGE, MAGE-C, and SSX mRNA. In patients with colon cancer, the expression of TSP50, MAGE-A(1-6), and SSX1,2,4 genes was associated with a poor prognosis, that of MAGE-C1 and XAGE1 was related to a favorable prognosis.

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.

Molecular imaging of fibrosis using a novel collagen-binding peptide labelled with 99mTc on SPECT/CT

Fibrosis, closely related to chronic various diseases, is a pathological process characterised by the accumulation of collagen (largely collagen type I). Non-invasive methods are necessary for the diagnosis and follow-up of fibrosis. This study aimed to develop a collagen-targeted probe for the molecular imaging of fibrosis. We identified CPKESCNLFVLKD (CBP1495) as an original collagen-binding peptide using isothermal titration calorimetry and enzyme-linked immunosorbent assay. CBP1495 effectively bound to collagen type I (K _d = 861 nM) and (GPO)₉ (K _d = 633 nM), a collagen mimetic peptide. Western blot and histochemistry validated CBP1495 targeting collagen in vitro and ex vivo. (Gly-(D)-Ala-Gly-Gly) was introduced to CBP1495 for coupling ^99mTc. Labelling efficiency of ^99mTc-CBP1495 was 95.06 ± 1.08 %. The physico-chemical properties, tracer kinetics and biodistribution of ^99mTc-CBP1495 were carried out, and showed that the peptide stably chelated ^99mTc in vitro and in vivo. SPECT/CT imaging with ^99mTc-CBP1495 was performed in rat fibrosis models, and revealed that ^99mTc-CBP1495 significantly accumulated in fibrotic lungs or livers of rats. Finally, ^99mTc-CBP1495 uptake and hydroxyproline (Hyp), a specific amino acid of collagen, were quantitatively analysed. The results demonstrated that ^99mTc-CBP1495 uptake was positvely correlated with Hyp content in lungs (P < 0.0001, r ² = 0.8266) or livers (P < 0.0001, r ² = 0.7581). Therefore, CBP1495 is a novel collagen-binding peptide, and ^99mTc-labelled CBP1495 may be a promising radiotracer for the molecular imaging of fibrosis.

Heat shock protein 70-2 (HSP70-2) is a novel therapeutic target for colorectal cancer and is associated with tumor growth

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer related deaths worldwide both in men and women. Our recent studies have indicated an association of heat shock protein 70-2 (HSP70-2) with bladder urothelial carcinoma. In the present study, we investigated the association of HSP70-2 with various malignant properties of colorectal cancer cells and clinic-pathological features of CRC in clinical specimens.

METHODS

HSP70-2 mRNA and protein was investigated expression by RT-PCR, immunohistochemistry, immunofluorescence, flow cytometry and Western blotting in CRC clinical specimens and COLO205 and HCT116 cell lines. Plasmid-based gene silencing approach was employed to study the association of HSP70-2 with various malignant properties of COLO205 and HCT116 cells in in vitro and with tumor progression in in vivo COLO205 human xenograft mice model.

RESULTS

HSP70-2 expression was detected in 78 % of CRC patients irrespective of various stages and grades by RT-PCR and IHC. Our analysis further revealed that HSP70-2 expression was detected in both COLO205 and HCT116 cell lines. Ablation of HSP70-2 expression resulted in reduced cellular growth, colony forming ability, migratory and invasive ability of CRC cells. In addition, ablation of HSP70-2 expression showed significant reduction in tumor growth in COLO205 human xenograft in in vivo mouse model.

CONCLUSION

Collectively, our results indicate that HSP70-2 is associated with CRC clinical specimens. In addition, down regulation of HSP70-2 expression reduces cellular proliferation and tumor growth indicating that HSP70-2 may be a potential therapeutic target for CRC treatment.

A novel cancer testis antigen target A-kinase anchor protein (AKAP4) for the early diagnosis and immunotherapy of colon cancer

Colorectal cancer (CRC) is mainly a disease of developed countries and a major cause of death worldwide. The present study was undertaken to investigate the association of novel cancer testis (CT) antigen, A-kinase anchor protein (AKAP4) with CRC. AKAP4 gene and protein was examined by RT-PCR, in situ hybridization and immunohistochemistry (IHC) in 200 clinical specimens of different stages and grades. In addition, humoral response against AKAP4 was detected by enzyme-linked immunosorbent assay and Western blotting in 172 available sera samples of CRC patients. We observed that majority of CRC patients demonstrated AKAP4 expression and elicited immune response. AKAP4 protein expression, based on immunoreactivity score (IRS) predicted presence of CRC with 84% sensitivity, 100% specificity, 100% of positive predictive value (PPV) and 83.33% negative predictive value (NPV). Humoral response against AKAP4 protein was generated in 82% of the CRC patients. Further, statistical analysis revealed that antibodies found against AKAP4 in CRC patients predicted presence of malignancy with 81.98% sensitivity, 100% specificity, 100% PPV, and 63.53% NPV. Collectively, our data suggests that the majority of CRC cases show significant difference of AKAP4 expression among stages and grades and also generated antibodies against AKAP4 protein. Therefore, AKAP4 may be potential candidate molecule for developing as a biomarker for early diagnosis and immunotherapy of CRC.

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.

Targeting cancer testis antigens for biomarkers and immunotherapy in colorectal cancer: Current status and challenges

Colorectal cancer ranks third among the estimated cancer cases and cancer related mortalities in United States in 2014. Early detection and efficient therapy remains a significant clinical challenge for this disease. Therefore, there is a need to identify novel tumor associated molecules to target for biomarker development and immunotherapy. In this regard, cancer testis antigens have emerged as a potential targets for developing novel clinical biomarkers and immunotherapy for various malignancies. These germ cell specific proteins exhibit aberrant expression in cancer cells and contribute in tumorigenesis. Owing to their unique expression profile and immunogenicity in cancer patients, cancer testis antigens are clinically referred as the most promising tumor associated antigens. Several cancer testis antigens have been studied in colorectal cancer but none of them could be used in clinical practice. This review is an attempt to address the promising cancer testis antigens in colorectal cancer and their possible clinical implications as biomarkers and immunotherapeutic targets with particular focus on challenges and future interventions.

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.

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.

HAGE (DDX43) is a biomarker for poor prognosis and a predictor of chemotherapy response in breast cancer

Background:

HAGE protein is a known immunogenic cancer-specific antigen.

Methods:

The biological, prognostic and predictive values of HAGE expression was studied using immunohistochemistry in three cohorts of patients with BC (n=2147): early primary (EP-BC; n=1676); primary oestrogen receptor-negative (PER-BC; n=275) treated with adjuvant anthracycline-combination therapies (Adjuvant-ACT); and primary locally advanced disease (PLA-BC) who received neo-adjuvant anthracycline-combination therapies (Neo-adjuvant-ACT; n=196). The relationship between HAGE expression and the tumour-infiltrating lymphocytes (TILs) in matched prechemotherapy and postchemotherapy samples were investigated.

Results:

Eight percent of patients with EP-BC exhibited high HAGE expression (HAGE+) and was associated with aggressive clinico-pathological features (Ps<0.01). Furthermore, HAGE+expression was associated with poor prognosis in both univariate and multivariate analysis (Ps<0.001). Patients with HAGE+did not benefit from hormonal therapy in high-risk ER-positive disease. HAGE+and TILs were found to be independent predictors for pathological complete response to neoadjuvant-ACT; P<0.001. A statistically significant loss of HAGE expression following neoadjuvant-ACT was found (P=0.000001), and progression-free survival was worse in those patients who had HAGE+residual disease (P=0.0003).

Conclusions:

This is the first report to show HAGE to be a potential prognostic marker and a predictor of response to ACT in patients with BC.

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.

New targets for the immunotherapy of colon cancer-does reactive disease hold the answer?

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers in both men and women, posing a serious demographic and economic burden worldwide. In the United Kingdom, CRC affects 1 in every 20 people and it is often detected once well established and after it has spread beyond the bowel (Stage IIA-C and Stage IIIA-C). A diagnosis at such advanced stages is associated with poor treatment response and survival. However, studies have identified two sub-groups of post-treatment CRC patients--those with good outcome (reactive disease) and those with poor outcome (non-reactive disease). We aim to review the state-of-the-art for CRC with respect to the expression of cancer-testis antigens (CTAs) and their identification, evaluation and correlation with disease progression, treatment response and survival. We will also discuss the relationship between CTA expression and regulatory T-cell (Treg) activity to tumorigenesis and tumor immune evasion in CRC and how this could account for the clinical presentation of CRC. Understanding the molecular basis of reactive CRC may help us identify more potent novel immunotherapeutic targets to aid the effective treatment of this disease. In this review, based on our presentation at the 2012 International Society for the Cell and Gene Therapy of Cancer annual meeting, we will summarize some of the most current advances in CTA and CRC research and their influence on the development of novel immunotherapeutic approaches for this common and at times difficult to treat disease.

Screening of a specific peptide binding to VPAC1 receptor from a phage display peptide library

Background/Purpose

The VPAC1 receptor, a member of the vasoactive intestinal peptide receptors (VIPRs), is overexpressed in the most frequently occurring malignant tumors and plays a major role in the progression and angiogenesis of a number of malignancies. Recently, phage display has become widely used for many applications, including ligand generation for targeted imaging, drug delivery and therapy. In this work, we developed a panning procedure using a phage display peptide library to select a peptide that specifically binds to the VPAC1 receptor to develop a novel targeted probe for molecular imaging and therapy.

Methods

CHO-K1 cells stably expressing VPAC1 receptors (CHO-K1/VPAC1 cells) were used to select a VPAC1-binding peptide from a 12-mer phage peptide library. DNA sequencing and homologous analysis of the randomly selected phage clones were performed. A cellular ELISA was used to determine the most selectively binding peptide for further investigation. Binding specificity to the VPAC1 receptor was analyzed by competitive inhibition ELISA and flow cytometry. The binding ability of the selected peptide to CHO-K1/VPAC1 cells and colorectal cancer (CRC) cell lines was confirmed using fluorescence microscopy and flow cytometry.

Results

A significant enrichment of phages that specifically bound to CHO-K1/VPAC1 cells was obtained after four rounds of panning. Of the selected phage clones, 16 out of 60 shared the same peptide sequence, GFRFGALHEYNS, which we termed the VP2 peptide. VP2 and vasoactive intestinal peptide (VIP) competitively bound to the VPAC1 receptor. More importantly, we confirmed that VP2 specifically bound to CHO-K1/VPAC1 cells and several CRC cell lines.

Conclusion

Our results demonstrate that the VP2 peptide could specifically bind to VPAC1 receptor and several CRC cell lines. And VP2 peptide may be a potential candidate to be developed as a useful diagnostic molecular imaging probe for early detection of CRC.

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.