Cathepsins B, L and cystatin C in cyst fluid of ovarian tumors

The PMA phorbol ester tumor promoter increases canonical Wnt signaling via macropinocytosis

Activation of the Wnt pathway lies at the core of many human cancers. Wnt and macropinocytosis are often active in the same processes, and understanding how Wnt signaling and membrane trafficking cooperate should improve our understanding of embryonic development and cancer. Here, we show that a macropinocytosis activator, the tumor promoter phorbol 12-myristate 13-acetate (PMA), enhances Wnt signaling. Experiments using the Xenopus embryo as an in vivo model showed marked cooperation between the PMA phorbol ester and Wnt signaling, which was blocked by inhibitors of macropinocytosis, Rac1 activity, and lysosome acidification. Human colorectal cancer tissue arrays and xenografts in mice showed a correlation of cancer progression with increased macropinocytosis/multivesicular body/lysosome markers and decreased GSK3 levels. The crosstalk between canonical Wnt, focal adhesions, lysosomes, and macropinocytosis suggests possible therapeutic targets for cancer progression in Wnt-driven cancers.

The PMA Phorbol Ester Tumor Promoter Increases Canonical Wnt Signaling Via Macropinocytosis

Activation of the Wnt pathway lies at the core of many human cancers. Wnt and macropinocytosis are often active in the same processes, and understanding how Wnt signaling and membrane trafficking cooperate should improve our understanding of embryonic development and cancer. Here we show that a macropinocytosis activator, the tumor promoter Phorbol 12-myristate 13-acetate (PMA), enhances Wnt signaling. Experiments using the Xenopus embryo as an in vivo model showed marked cooperation between the PMA phorbol ester and Wnt signaling, which was blocked by inhibitors of macropinocytosis, Rac1 activity, and lysosome acidification. Human colorectal cancer tissue arrays and xenografts in mice showed a correlation of cancer progression with increased macropinocytosis/multivesicular body/lysosome markers and decreased GSK3 levels. The crosstalk between canonical Wnt, focal adhesions, lysosomes, and macropinocytosis suggests possible therapeutic targets for cancer progression in Wnt-driven cancers.

Smart Delivery Systems Responsive to Cathepsin B Activity for Cancer Treatment

Cathepsin B is a lysosomal cysteine protease, contributing to vital cellular homeostatic processes including protein turnover, macroautophagy of damaged organelles, antigen presentation, and in the extracellular space, it takes part in tissue remodeling, prohormone processing, and activation. However, aberrant overexpression of cathepsin B and its enzymatic activity is associated with different pathological conditions, including cancer. Cathepsin B overexpression in tumor tissues makes this enzyme an important target for smart delivery systems, responsive to the activity of this enzyme. The generation of technologies which therapeutic effect is activated as a result of cathepsin B cleavage provides an opportunity for tumor-targeted therapy and controlled drug release. In this review, we summarized different technologies designed to improve current cancer treatments responsive to the activity of this enzyme that were shown to play a key role in disease progression and response to the treatment.

An efficient and concise synthesis of a selective small molecule non-peptide inhibitor of cathepsin L: KGP94

KGP94 is a potent, selective, and competitive inhibitor of the lysosomal endopeptidase enzyme (Cathepsin L) currently in preclinical trials for the treatment of metastatic cancer, which is a leading cause of cancer-associated death. Herein, we report two new synthetic routes for synthesizing the target compound through four consecutive steps, using a Weinreb amide approach starting from a common 3-bromobenzoyl chloride. A key step in the approach is a coupling reaction of a readily available Grignard reagent with amide 4 to produce 6, a previously unreported coupling pattern. These new strategies offer an efficient and alternative approach to synthesis of target compound with an excellent overall yield.

The potential of cystatin C as a predictive biomarker in breast cancer

INTRODUCTION

Breast cancer (BCa) is the leading cause of cancer-related deaths among women. Numerous efforts are being directed toward identifying novel tissue and/or circulating molecular markers that may help clinicians in detecting early-stage BCa patients and in providing an accurate estimation of the prognosis and prediction of response to clinical treatments. In this setting, emerging evidence has indicated Cystatin C (Cyst C), as the most potent endogenous inhibitor of cysteine cathepsins, as a possible useful marker in the clinical management of BCa patients.

AREAS COVERED

This review analyzes the results of emerging studies underpinning a potential clinical role of Cyst C, as additional marker in BCa.

EXPERT OPINION

Cyst C expression levels have been reported to be altered in tumor tissues and/or in biological fluids of BCa patients. Furthermore, clinical evidence has highlighted a significant correlation between altered Cyst C levels in tumor tissues and/or biological fluids and some clinco-biological parameters of BCa progression. These findings provide evidence for a potential clinical use of Cyst C as a novel marker to improve the clinical and therapeutic management of BCa patients and as a gauge for better clarifying the role of cysteine proteinases in the various steps of BCa progression.

Ultrasensitive, multiplexed chemoproteomic profiling with soluble activity-dependent proximity ligation

Chemoproteomic methods can report directly on endogenous, active enzyme populations, which can differ greatly from measures of transcripts or protein abundance alone. Detection and quantification of family-wide probe engagement generally requires LC-MS/MS or gel-based detection methods, which suffer from low resolution, significant input proteome requirements, laborious sample preparation, and expensive equipment. Therefore, methods that can capitalize on the broad target profiling capacity of family-wide chemical probes but that enable specific, rapid, and ultrasensitive quantitation of protein activity in native samples would be useful for basic, translational, and clinical proteomic applications. Here we develop and apply a method that we call soluble activity-dependent proximity ligation (sADPL), which harnesses family-wide chemical probes to convert active enzyme levels into amplifiable barcoded oligonucleotide signals. We demonstrate that sADPL coupled to quantitative PCR signal detection enables multiplexed "writing" and "reading" of active enzyme levels across multiple protein families directly at picogram levels of whole, unfractionated proteome. sADPL profiling in a competitive format allows for highly sensitive detection of drug-protein interaction profiling, which allows for direct quantitative measurements of in vitro and in vivo on- and off-target drug engagement. Finally, we demonstrate that comparative sADPL profiling can be applied for high-throughput molecular phenotyping of primary human tumor samples, leading to the discovery of new connections between metabolic and proteolytic enzyme activity in specific tumor compartments and patient outcomes. We expect that this modular and multiplexed chemoproteomic platform will be a general approach for drug target engagement, as well as comparative enzyme activity profiling for basic and clinical applications.

Cathepsins: Potent regulators in carcinogenesis

Cathepsins (CTS) are mainly lysosomal acid hydrolases extensively involved in the prognosis of different diseases, and having a distinct role in tumor progression by regulating cell proliferation, autophagy, angiogenesis, invasion, and metastasis. As all these processes conjunctively lead to cancer progression, their site-specific regulation might be beneficial for cancer treatment. CTS regulate activation of the proteolytic cascade and protein turnover, while extracellular CTS is involved in promoting extracellular matrix degradation and angiogenesis, thereby stimulating invasion and metastasis. Despite cancer regulation, the involvement of CTS in cellular adaptation toward chemotherapy and radiotherapy augments their therapeutic potential. However, lysosomal permeabilization mediated cytosolic translocation of CTS induces programmed cell death. This complex behavior of CTS generates the need to discuss the different aspects of CTS associated with cancer regulation. In this review, we mainly focused on the significance of each cathepsin in cancer signaling and their targeting which would provide noteworthy information in the context of cancer biology and therapeutics.

Increased phosphorylation of eIF2α in chronic myeloid leukemia cells stimulates secretion of matrix modifying enzymes

Recent studies underscore the role of the microenvironment in therapy resistance of chronic myeloid leukemia (CML) cells and leukemia progression. We previously showed that sustained mild activation of endoplasmic reticulum (ER) stress in CML cells supports their survival and resistance to chemotherapy. We now demonstrate, using dominant negative non-phosphorylable mutant of eukaryotic initiation factor 2 α subunit (eIF2α), that phosphorylation of eIF2α (eIF2α-P), which is a hallmark of ER stress in CML cells, substantially enhances their invasive potential and modifies their ability to secrete extracellular components, including the matrix-modifying enzymes cathepsins and matrix metalloproteinases. These changes are dependent on the induction of activating transcription factor-4 (ATF4) and facilitate extracellular matrix degradation by CML cells. Conditioned media from CML cells with constitutive activation of the eIF2α-P/ATF4 pathway induces invasiveness of bone marrow stromal fibroblasts, suggesting that eIF2α-P may be important for extracellular matrix remodeling and thus leukemia cells-stroma interactions. Our data show that activation of stress response in CML cells may contribute to the disruption of bone marrow niche components by cancer cells and in this way support CML progression.

Cystatin C deficiency suppresses tumor growth in a breast cancer model through decreased proliferation of tumor cells

Cysteine cathepsins are proteases that, in addition to their important physiological functions, have been associated with multiple pathologies, including cancer. Cystatin C (CstC) is a major endogenous inhibitor that regulates the extracellular activity of cysteine cathepsins. We investigated the role of cystatin C in mammary cancer using CstC knockout mice and a mouse model of breast cancer induced by expression of the polyoma middle T oncoprotein (PyMT) in the mammary epithelium. We showed that the ablation of CstC reduced the rate of mammary tumor growth. Notably, a decrease in the proliferation of CstC knockout PyMT tumor cells was demonstrated ex vivo and in vitro, indicating a role for this protease inhibitor in signaling pathways that control cell proliferation. An increase in phosphorylated p-38 was observed in CstC knockout tumors, suggesting a novel function for cystatin C in cancer development, independent of the TGF-β pathway. Moreover, proteomic analysis of the CstC wild-type and knockout PyMT primary cell secretomes revealed a decrease in the levels of 14-3-3 proteins in the secretome of knock-out cells, suggesting a novel link between cysteine cathepsins, cystatin C and 14-3-3 proteins in tumorigenesis, calling for further investigations.

Targeting Cathepsin B for Cancer Therapies

Cathepsin B is a member of the papain family of cysteine proteases normally present in the lysosome, but it can translocate and function to degrade components of the extracellular matrix. It exhibits carboxyopeptidase, peptidyldipepidase, and endopeptidase activity. Aberrant overexpression of cathepsin B has been reported in invasive and metastatic cancers, including breast cancer, melanoma and colorectal cancer. It has been shown that oncogenic activation, such as the signaling of the ErbB pathways, can lead to cathepsin B overexpression. The degradation of the extracellular matrix is a key factor for cathepsin B to contribute to development and metastasis of tumors. An example of substrates for cathepsin B is E-cadherin, which is involved in adherens junctions, and the downregulation of E-cadherin in cancer is directly linked to invasion and metastasis. Recent studies also point to a role for cathepsin B in macrophages in the tumor microenvironment. The structure of cathepsin B is crystallographically solved, and several highly selective and potent inhibitors for cathepsin B have been developed. Yet it remains to be a challenge to demonstrate the clinical utility or benefit of any cathepsin B inhibitor. As cathepsin B is required for a cellular process called lysosomal membrane permeabilization (LMP), inhibition of cathepsin B would protect cancer cells from cell death induced by chemotherapeutic agents. It is expected that combining cathepsin B inhibitors with other approaches, such as nanoparticles, to direct the inhibition to the extracellular space may lead to better clinical approaches to treat cancers and metastasis.

Screening and identification of small molecule inhibitors of ErbB2-induced invasion

ERBB2 amplification and overexpression are strongly associated with invasive cancer with high recurrence and poor prognosis. Enhanced ErbB2 signaling induces cysteine cathepsin B and L expression leading to their higher proteolytic activity (zFRase activity), which is crucial for the invasion of ErbB2‐positive breast cancer cells in vitro. Here we introduce a simple screening system based on zFRase activity as a primary readout and a following robust invasion assay and lysosomal distribution analysis for the identification of compounds that can inhibit ErbB2‐induced invasion. With an unbiased kinase inhibitor screen, we identified Bohemine/Roscovitine, Gö6979 and JAK3 inhibitor VI as compounds that can efficiently decrease cysteine cathepsin activity. Using the well‐established and clinically relevant ErbB1 and ErbB2 inhibitor lapatinib as a positive control, we studied their ability to inhibit ErbB2‐induced invasion in 3‐dimensional Matrigel cultures. We found one of them, JAK3 inhibitor VI, capable of inhibiting invasion of highly invasive ErbB2‐positive ovarian cancer cells as efficiently as lapatinib, whereas Gö6979 and Roscovitine displayed more modest inhibition. All compounds reversed the malignant, ErbB2‐induced and invasion‐supporting peripheral distribution of lysosomes. This effect was most evident for lapatinib and JAK3 inhibitor VI and milder for Gö6979 and Roscovitine. Our results further showed that JAK3 inhibitor VI function was independent of JAK kinases but involved downregulation of cathepsin L. We postulate that the screening method and the verification experiments that are based on oncogene‐induced changes in lysosomal hydrolase activity and lysosomal distribution could be used for identification of novel inhibitors of ErbB2‐induced invasiveness. Additionally, we introduce a novel function for lapatinib in controlling malignant lysosomal distribution, that may also be involved in its capability to inhibit ErbB2‐induced invasion in vivo.

Setting up a robust screening system for identification of inhibitors of ErbB2‐induced invasion.

Establishment of a 3‐dimensional model system to study invasion of ErbB2‐positive ovarian cancer cells.

Identification of JAK3 inhibitor VI as a compound that efficiently abrogates ErbB2‐induced cellular invasion.

Identification of lapatinib and JAK3 inhibitor VI as regulators of lysosome trafficking.

Serum HE4, CA125, YKL-40, bcl-2, cathepsin-L and prediction optimal debulking surgery, response to chemotherapy in ovarian cancer

Background

The most important prognostic factor in the ovarian cancer is optimal cytoreduction. The neoadjuvant chemotherapy, an only optional method of treatment in this case and is still the subject of debate. The object of this study was to evaluate the usefulness of markers: CA 125, HE4, YKL-40 and bcl-2 as well as cathepsin L in predicting optimal cytoreduction and response to chemotherapy.

Methods

Sera were secured preoperatively. The division into groups was performed retrospectively depending on the method of treatment (surgery vs neoadjuvant chemotherapy) as well as on response to chemotherapy (sensitive vs resistant vs refractory). Comparisons were made between groups, and the diagnostic usefulness of tested proteins was examined.

Results

We found that statistically significant differences between primary operated patients and patients undergoing neoadjuvant chemotherapy were applicable only to the tumour markers (CA125 1206.79 vs 2432.38, p = 0.000191; HE4 78.87 vs 602.45, p = 0.000004; YKL-40 108.13 vs 203.96, p = 0.003991). Cathepsin-L and Bcl-2 were statistically insignificant. The cut-off point values were determined for the CA 125 (345 mIU/ml), HE4 (218.43 pmol/L) and YKL-40 (140.9 ng/ml). The sensitivity, specificity, PPV and NPV were as follows: CA125 (83.3%; 75%; 80.6%; 78.3%), HE4 (86.6%; 91.3%; 92.9%; 84%) and YKL-40 (75%; 83.3%; 84%; 74.1%).

Conclusion

Among the tested proteins the HE4 marker appears to be helpful in forecasting of optimal cytoreduction and possibly also of the prediction of response to platinum analogues used in first-line treatment of ovarian cancer.

Effect of EGb761 on light-damaged retinal pigment epithelial cells

AIM

To investigate the protective mechanism of Gingko Biloba extract (EGb761) on the ability of retinal pigment epithelial (RPE) cells to resist light-induced damage in a comparative proteomics study.

METHODS

Human RPE cells (ARPE-19) were randomly distributed to one of three groups: normal control (NC group) and light-damaged model without or with EGb761 group (M and ME groups, respectively). The light-damaged model was formed by exposing to white light (2 200±300)lx for 6h. The RPE cells in ME group were conducted with EGb 761 (100µg/mL) before light exposure. The soluble cellular proteins extracting from each groups were separated by two-dimensional electrophoresis and stained by silver staining. Different proteins in the profiles of the gels were analyzed by Image Master Software. Two-fold expressing protein spots were identified by Matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) mass spectrometry.

RESULTS

NC, M and ME groups displayed 1 892±71, 2 145±23 and 2 216±85 protein spots, respectively. We identified 33 proteins with different expression levels between the NC and M groups, 25 proteins between the M and ME groups, and 11 proteins between the NC and ME groups. MALDI-TOF/TOF mass spectrometry successfully identified 16 proteins, including metabolic enzymes, cytoskeletal proteins, anti-oxidation proteins, and others.

CONCLUSION

Differences in some important proteins, such as cathepsin B, heat shock protein, and cytochrome c reductase, indicated that multiple pathways may be induced in light-damaged RPE cells and the protective effect of EGb761.

Overexpression of cysteine cathepsin L is a marker of invasion and metastasis in ovarian cancer

Cysteine cathepsins (CTSs) are involved in the degradation and remodeling of the extracellular matrix and are associated with cellular transformation, differentiation, motility and adhesion in cancer development. Previous studies indicate that CTSs may be involved in ovarian cancer invasion and metastasis. However, due to the lack of large sample clinical studies and direct experimental evidence for the relationship between the expression of CTSs and invasion and metastasis, the diagnostic and prognostic value of CTSs in ovarian cancer progression has not been elucidated. In the present study, we observed that expression levels of CTSB, CTSL and CC in malignant ovarian tumors were significantly higher than the expression levels in benign tumors and normal ovarian tissues, yet their associations with clinicopathological features varied. In particular, CTSL was related to lymph node metastasis, CC was related to liver metastasis and omental metastasis, and CTSB and CTSL expression levels were found to be independent prognostic factors in ovarian cancer. Further study indicated that the serum level of CTSL was significantly higher in patients with ovarian malignant tumors than the levels in benign tumors and healthy controls, and the levels were elevated in low grade and advanced stage compared to the levels in high grade and early stage disease, suggesting that the serum level of CTSL may be a useful serum marker for the diagnosis of ovarian cancer. Furthermore, the expression of CTSL in ovarian cancer cells can greatly enhance the ability of cell invasion and metastasis, although no change was observed for cell adhesion. Taken together, we demonstrated that the overexpression of CTSL is involved in tumor invasion and metastasis, and the CTSL level in serum may be a marker for invasion and metastasis in ovarian cancer.

Evaluation of serum procathepsin B, cystatin B and cystatin C as possible biomarkers of ovarian cancer

Objectives

To evaluate procathepsin B, as well as endogenous inhibitors of cysteine proteases (cystatin B and cystatin C) in biological fluids as possible biomarkers of ovarian cancer. To observe levels of serum procathepsin B in different age groups.

Study design

The sample (N=27) of women with gynaecological tumours included 18 patients with ovarian cancer (n=18) and 9 patients with benign ovarian tumours (n=9); 72 healthy women were in the control group. All patients were treated in Novosibirsk Regional Oncological Center, Russia. Serum samples of healthy women (n=40) aged 18–70 years were used as controls for common biomarker of ovarian cancer CA-125. In the Procathepsin B study, serum samples of healthy women (n=32) aged 18–40 years (n=14), 41–55 years (n=10) and 56–80 (n=8) years were used as controls.

Methods

Common biomarker of ovarian cancer, CA-125, was assayed by using a commercial kit (Vector, Koltsovo, Novosibirsk Region, Russia). Procathepsin B was measured by means of a commercial kit for human procathepsin B (R&D, USA); cystatin C was measured by commercial ELISA kits for human (BioVendor, Czechia); cystatin B was measured by ELISA kits for human (USCN Life Science Inc., Wuhan, China). Statistical analysis was performed by one-way ANOVA (Statistica 10 Program).

Results

In the control group, serum procathepsin B concentration did not reveal age dependency. In the ovarian cancer group, both levels of serum procathepsin B and standard biomarker CA-125 increased significantly (both p<0.001) compared with the control group. In the benign ovarian tumour group, serum procathepsin B (p<0.001) and CA-125 (p=0.004) increased about 2.5- and 8-fold compared to the control group. Serum cystatin B level increased up to 1.7-fold in the ovarian cancer group compared to the control group. The increase of serum CA-125 was about 3.5-fold higher (p=0.017) and procathepsin B was 1.8-fold higher (p<0.05) in the ovarian cancer group compared to the benign tumour group. Cystatin B in ascites fluid increased equally in both ovarian cancer (p<0.001) and benign ovarian tumours group (p<0.05). Cystatin C concentration in ascites fluid increased only in patients with ovarian cancer (p<0.05) and did not change in the benign tumours group. Large increases of procathepsin B level (about 13-fold, p<0.001) and to a lesser degree of cystatin C (1.8-fold, p<0.05) and cystatin B levels (1.4 fold, p<0.001) were revealed in ascites fluids of patients with ovarian cancer compared to the control serum.

The significant difference in serum procathepsin B levels was noted between the ovarian cancer and benign tumour groups (p<0.05), which could be used in differential diagnostics between malignant and benign gynaecological tumours.

Conclusion

Serum procathepsin B demonstrated significant promise as a new biomarker of ovarian cancer.

Cathepsin L inhibition by the small molecule KGP94 suppresses tumor microenvironment enhanced metastasis associated cell functions of prostate and breast cancer cells

Metastasis remains the major cause of therapeutic failure, poor prognosis and high mortality in breast and prostate cancer patients. Aberrant microenvironments including hypoxia and acidic pH are common features of most solid tumors that have been long associated with enhanced metastasis and poor patient outcomes. Novel approaches to reduce metastatic incidences and improve overall survival of cancer patients clearly are needed. The crucial role of Cathepsin L (CTSL) in the dissemination of tumor cells has led to the development of novel cathepsin L inhibition strategies. The present study evaluated the ability of KGP94, a small molecule inhibitor of CTSL, to impair the metastatic phenotype of prostate (PC-3ML) and breast (MDA-MB-231) cancer cells both under normal and aberrant microenvironmental conditions. To assess the role of CTSL in hypoxia and acidosis triggered metastasis associated cell functions, secreted CTSL levels were determined under conditions pertinent to the tumor microenvironment. Acute exposures to hypoxic or acidic conditions significantly elevated secreted CTSL levels either through an increase in intracellular CTSL levels or through activation of lysosomal exocytosis or both, depending on the tumor type. Increases in CTSL secretion closely paralleled enhanced tumor cell migration and invasion suggesting that CTSL could be an essential factor in tumor microenvironment triggered metastasis. Importantly, KGP94 treatment led to marked attenuation of tumor cell invasion and migration under both normal and aberrant microenvironmental conditions suggesting that it may have significant utility as an anti-metastatic agent.

Combined detection of serum matrix metalloproteinase 9, acetyl heparinase and cathepsin L in diagnosis of ovarian cancer

OBJECTIVE

To investigate the clinic values of combining test of serum matrix metalloproteinase 9 (MMP-9), acetyl heparinase (Hpa) and Cathepsin L (CL) in diagnosis of ovarian cancer.

METHODS

Serum levels of MMP-9, Hpa and CL were detected in a total of 418 cases, including 217 cases with ovarian malignant tumor, 100 cases with ovarian benign tumor and 101 healthy controls, by using enzyme-linked immunosorbent assay (ELISA). Their correlation with clinicopathologic feature of ovarian malignant tumor was analyzed and their diagnosis performance was evaluated by receiver operating characteristic (ROC). The combined diagnosis model was established by logistic regression analysis.

RESULTS

The serum levels of MMP-9, Hpa and CL were significantly higher in patients with ovarian malignant tumor than in benign tumor and healthy control, the serum levels of CL and Hpa were higher in epithelial cancer than in non-epithelial tumor, and MMP-9, Hpa and CL were elevated in low grade and advanced stage compared to high grade and early stage. The sensitivity for diagnosis of ovarian malignant tumor from high to low was CL, Hpa and MMP-9, and the specificity was MMP-9, CL and Hpa. The united diagnosis model was established and showed the sensitivity and specificity of combined detection were 84.6% and 82.1%, respectively, which were significantly higher than a single tumor marker.

CONCLUSION

Serum MMP-9, Hpa and CL were correlated with ovarian malignant tumor and the combined detection of which may be valuable for clinical diagnosis of ovarian malignant tumor.

Interaction of the hepatitis B spliced protein with cathepsin B promotes hepatoma cell migration and invasion

Hepatitis B spliced protein (HBSP) is involved in the pathogenicity and/or persistence of hepatitis B virus (HBV). Chronic HBV infection is one of the most important risk factors for the development of hepatocellular carcinoma (HCC). However, whether or not HBSP contributes to the progression of HBV-associated HCC remains unknown. This study reports that overexpression of HBSP in human hepatoma cells increased cell invasion and motility. Conversely, small interfering RNA (siRNA)-mediated knockdown of HBSP expression inhibited migration and invasion. By glutathione S-transferase (GST) pulldown, coimmunoprecipitation, and a mammalian two-hybrid assay, HBSP was found to directly interact with cathepsin B (CTSB). Similar to HBSP knockdown, knocking down CTSB also reduced cell migration and invasion. Furthermore, the HBSP-overexpressing hepatoma cells were shown to have increased expression and activity of matrix metalloproteinase-9 (MMP-9) and urokinase-type plasminogen activator (uPA), and overexpression of HBSP significantly enhanced tumor-induced vascularization of endothelial cells. In contrast, knockdown of either HBSP or CTSB by siRNA resulted in inhibition of the two proteolytic enzymes and of the in vitro angiogenesis. Expression of HBSP in the hepatoma cells appeared to activate the mitogen-activated protein kinase (MAPK) and Akt signaling pathway, as evidenced by increases in phosphorylation of p38, Jun N-terminal protein kinase (JNK), extracellular signal-regulated kinase (ERK), and Akt. Taken together, these findings imply that interaction of HBSP with CTSB may promote hepatoma cell motility and invasion and highlight new molecular mechanisms for HBSP-induced HCC progression that involve the secretion and activation of proteolytic enzymes, increased tumor-induced angiogenesis, and activation of the MAPK/Akt signaling, thereby leading to the aggressiveness of hepatoma cells.

Increased expression of cysteine cathepsins in ovarian tissue from chickens with ovarian cancer

BACKGROUND

Cysteine cathepsins (CTSs) are involved in the degradation and remodeling of the extracellular matrix and are associated with cell transformation, differentiation, motility, and adhesion. These functions are also related to cancer cell invasion and metastasis. Chickens spontaneously develop epithelial ovarian cancer and are therefore a good animal model for human ovarian cancer. However, no studies have investigated the expression of CTSs in chickens with ovarian cancer.

METHODS

Cancerous (n = 5) and normal (n = 3) ovaries were collected from 2-to 3-year-old hens, and ovarian tissue samples were collected for study. Ovarian cancers were evaluated with hematoxylin and eosin staining. Reverse transcriptase and quantitative PCR analyses, in situ hybridization analysis were performed to examine the mRNA expression pattern of three CTSs in detail, and protein expression of CTSB was evaluated.

RESULTS

The CTSB, CTSC, and CTSS genes were highly expressed in cancerous chicken ovaries. Messenger RNAs for the three CTSs were localized to a nodule area, a major characteristic of cancerous ovaries, but the three CTSs showed no specific localization in normal ovaries. Immunoreactive CTSB protein was present in the nodule area of cancerous ovaries.

CONCLUSION

Our results suggest that CTSB, CTSC, and CTSS have important functions in the development of epithelial ovarian cancer.

The balance between extracellular cathepsins and cystatin C is of importance for ovarian cancer

BACKGROUND

A major step in cancer formation involves the degradation of the extracellular matrix, mediated by multiple degradative actions of (lysosomal) proteases. Extracellular release of lysosomal proteases (cathepsins) and their inhibitors has been associated with the development and progression of several types of cancer. We investigated whether cathepsins in ovarian cyst fluid (oCF) were associated with disease outcome in patients with epithelial ovarian cancer (EOC).

MATERIALS AND METHODS

The levels of cathepsin B (CatB), H (CatH), L (CatL) and X (CatX) and their most abundant extracellular inhibitor cystatin C (CysC) were determined in oCF of 50 EOC patients by quantitative ELISAs. The cathepsin levels and ratios between cathepsins and CysC were related to clinicopathological parameters (Mann-Whitney U and Kruskal-Wallis tests) and survival (Cox Regression analysis).

RESULTS

Median (25th-75th percentile) levels of cathepsin B, H, L, X and CysC in oCF were 97 (42-203), 18 (12-32), 61 (37-108), 20 (13-47) and 657 (501-805) ng mL(-1) respectively. Ratio of CysC/CatB was significantly lower for patients with metastatic compared with localised EOC (P = 0.025). Ratios of CysC/CatH and CysC/CatX differed significantly between histological subtypes (P = 0.012 and P = 0.035 respectively) and were significantly higher for high-grade tumours compared with low-grade tumours (P = 0.031 and P = 0.039 respectively). Neither cathepsins nor their ratios were significant predictors of survival for EOC patients.

CONCLUSIONS

Ratios between CysC and cathepsins in oCF differed significantly between important clinicopathological subgroups. We believe that a complex cascade of proteolytic events, in which cathepsins play different roles, might be responsible for progression and metastasis in EOC.