Maspin, a serpin with tumor-suppressing activity in human mammary epithelial cells

Elevated expression of maspin mRNA as a predictor of survival in stage II and III gallbladder cancer cases

BACKGROUND

Maspin expression is a potential prognostic factor for various malignancies but its relation with gallbladder cancer is unknown and needs to be investigated needs to be investigated. We therefore here focused on maspin mRNA expression in normal, gall stone disease and gallbladder cancer subjects, with particular attention to prognostic importance in individuals with malignancies.

MATERIALS AND METHODS

This study was carried out at the Department of Surgical Gastroenterology, King George's Medical University, Lucknow, India. Gallbladder samples from normal (n=25), gall stone disease (n=25) and cancer patients (n=38) were analysed for maspin mRNA expression by semi-quantitative reverse transcriptase PCR and quantitative real time PCR. Statistical analysis was carried out using the Students t test or ANOVA. Survival analysis was conducted according to the Kaplan-Meier method and correlations were assessed using the Pearson correlation method. p<0.05 was considered statistically significant.

RESULTS

Significant increase (p=0.028) in expression of maspin mRNA was observed in gallbladder cancer as compared to gall stone disease, whereas no expression was found in normal tissues. Significant correlation (Pearson's coefficient(r)=-0.798, p<0.0001) was observed between relative quantification of maspin mRNA and survival of cancer patients after surgery, with significantly shorter (p=0.002) survival in patients having relative quantification >1.5 as compared to those having relative quantification <1.5. Similarly, significant differences in patient survival for maspin mRNA expression was observed for stage II (p=0.025) and III (p=0.011) cancer.

CONCLUSIONS

Higher expression of maspin mRNA in gallbladder cancer has prognostic significance for stage II and III cancer, which needs to be investigated further.

Cytoplasmic maspin expression predicts poor prognosis of patients with soft tissue sarcomas

BACKGROUND

Maspin is a 42 kDa protein known to act as a tumor suppressor. Although its function has not been fully elucidated, numerous reports have investigated the prognostic impact of maspin in patients with several types of cancer. However, there have been no reports on the association between maspin expression and the prognosis of patients with soft tissue sarcomas (STS). The aim of this study was thus to explore the association of maspin expression with the prognosis of patients with STS.

METHODS

One-hundred and eight paraffin-embedded STS tissue samples were immunohistochemically analyzed using antibodies for maspin and Ki-67 antigen. The patients were followed up for 1 to 300 months (median: 33 months) and the prognostic value was evaluated by log-rank test and Cox's regression hazard model.

RESULTS

Cytoplasmic maspin expression was observed in 48.1% of specimens, and was significantly correlated with a higher FNCLCC grade (P = 0.002) and the presence of distant metastases (P = 0.001), and those with cytoplasmic maspin expression had both shorter disease-free survival (DFS) and overall survival (OS) by log-rank test (P <0.001, P = 0.001, respectively). By Cox's multivariate analysis, the presence of distant metastases was the only prognostic factor for DFS and OS.

CONCLUSIONS

This is the first report to reveal an association between maspin expression and the prognosis of patients with STS. Although further studies with a larger series of patients and a longer follow-up period will be needed, cytoplasmic maspin expression could be an indicator of unfavorable prognosis in patients with STS.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_205.

Discovery of prognostic factors for diagnosis and treatment of epithelial-derived ovarian cancer from laying hens

Ovarian cancer is a lethal gynecological cancer causing cancer-related deaths in women worldwide. It is difficult to diagnosis at an early stage when more than 90% patients can be cured because of lack of specific symptoms and early detection markers. Most of malignant ovarian tumors are originated from the germinal epithelium of the ovary. For investigation with animal models of epithelial-derived ovarian cancer (EOC), laying hens are the most relevant animal models because they spontaneously develop EOC as occurs in women through ovulating almost every day. As in women, EOC in the hen is age-related and grossly and histologically similar to that in women. However, domesticated animals are inappropriate for research human EOC due to multiple pregnancies and lactating or seasonally anestrous. In addition, the non-spontaneous nature of rodents EOC limits clinical relevance with human EOC. Recent studies have shown that ovarian cancer could arise from epithelium from the oviduct as oviduct-related genes are up-regulated in EOC of hens. Therefore, we showed in the review: 1) characterization and classification of EOC; 2) chicken models for EOC; 3) relationship estrogen with EOC; 4) candidate prognostic factors for EOC including serpin peptidase inhibior, clade B (ovalbumin), member 3 (SERPINB3), SERPINB11, gallicin 11 (GAL11), secreted phosphoprotein 1 (SPP1) and alpha 2 macroglobulin (A2M) in normal and cancerous ovaries of laying hens; 5) biological roles of microRNAs in development of EOC. Collectively, the present reviews indicate that expression of SERPINB3, SERPINB11, GAL11, SPP1 and A2M is clearly associated with the development of ovarian carcinogenesis. These results provide new insights into the prognostic biomarkers for EOC to diagnose and to evaluate responses to therapies for treating EOC of humans.

Internalization by multiple endocytic pathways and lysosomal processing impact maspin-based therapeutics

Patients with metastatic disease face high rates of mortality with a paucity of therapeutic options. Protein-based therapeutics provide advantages over traditional chemotherapy through increased specificity, decreased immune impairment, and more direct means of delivery. However, development is often hindered because of insufficient knowledge about protein processing by cells when exogenously applied. This study focuses on recombinant Maspin (rMaspin), a serine protease inhibitor (SERPINB5), which alters invasive properties when directly applied to cancer cells. Previous evidence suggests differences in the effects of rMaspin treatment when compared with endogenous reexpression, with little explanation for these discrepancies. A leading hypothesis is that exogenously applied rMaspin is subject to different regulatory and/or processing mechanisms in cancer cells when compared with endogenous expression. Therefore, a more detailed understanding of the mechanisms of internalization and subcellular trafficking of rMaspin is needed to guide future translational development. We describe the molecular trafficking of rMaspin in cytoplasmic vesicles of the endosomal/lysosomal pathway and characterize its uptake by multiple endocytic mechanisms. Time-lapse laser scanning confocal microscopy shows the uptake, in real time, of dye-labeled rMaspin in cancer cells. This study indicates that cellular processing of rMaspin plays a key role by affecting its biologic activity and highlights the need for new approaches aimed at increasing the availability of rMaspin when used to treat cancer.

IMPLICATIONS

Novel characterization of internalization and subcellular trafficking of rMaspin provides new insights for future therapeutic development.

Decreased maspin combined with elevated vascular endothelial growth factor C is associated with poor prognosis in non-small cell lung cancer

BACKGROUND

This study aimed to investigate the clinical significance of the combination of maspin and vascular endothelial growth factor (VEGF)-C expression in the prognosis of non-small cell lung cancer (NSCLC).

METHODS

Immunohistochemistry was performed to assay the expression of maspin and VEGF-C in primary tumor tissues, metastatic, and non-metastatic lymph nodes in 98 NSCLC patients. Survival analysis was determined by Kaplan-Meier curves.

RESULTS

The positive expression rate of maspin was 26.5% (26/98) in NSCLC primary tumor tissues, significantly associated with histological type (P = 0.005) and the absence of nodal metastasis (P < 0.001). The expression of maspin in primary tumor tissues was stronger than metastatic lymph nodes of the N1 group (P = 0.048), while the metastatic lymph nodes of the N1 group had a stronger maspin expression than the N2 group (P = 0.008). In survival analysis, a positive expression of maspin of the N1 lymph node was also found to be an independent positive prognostic factor in overall survival (P = 0.003). We also found that decreased maspin combined with elevated VEGF-C is associated with a poor prognosis for disease-free survival (P = 0.019).

CONCLUSION

Our results suggest that positive expression of maspin might significantly inhibit nodal metastasis in NSCLC. Decreased maspin combined with elevated VEGF-C might be associated with a poor prognosis in NSCLC.

Promoter hypomethylation and increased maspin expression in preeclamptic placentas in a Chinese population

OBJECTIVE

Preeclampsia is thought to begin with shallow trophoblast invasion and inadequate spiral artery remodeling. Maspin, a tumor-suppressor gene, plays a regulatory role in trophoblast invasion and motility. The tissue-specific methylation of the maspin promoter can regulate maspin gene expression in various cancers. We sought to detect maspin gene expression and assess the degrees of methylation of maspin promoter regions in preeclamptic placentas in the Han Chinese population and to investigate the potential role of maspin in the pathophysiology of preeclampsia.

METHODS

We conducted RT-PCR, immunohistochemistry and western blotting to characterize maspin gene expression and protein levels in the placentas from normal and preeclamptic pregnancies. Finally, using methylation-specific PCR and bisulfite sequencing PCR, we detected the degrees of methylation of the promoter regions of maspin in each of the two studied groups.

RESULTS

Maspin expression was increased at the mRNA and protein levels in the preeclamptic placentas compared to the control group. Maspin immunohistochemical staining revealed positive staining in the syncytio-cytotrophoblast layers and more diffuse staining in the preeclamptic group. The mean methylation level of the analyzed promoter region was significantly hypomethylated in the preeclamptic placentas compared to the control placentas, pointing to a negative relationship between maspin promoter methylation and gene expression.

DISCUSSION

Hypomethylation of the maspin promoter results in increased expression of maspin in preeclamptic placentas, which suggests a negative relationship between maspin methylation and maspin expression in this Han Chinese population. Thus, maspin is likely involved in the etiology of preeclampsia.

Aspirin use and survival after the diagnosis of breast cancer: a population-based cohort study

BACKGROUND

Aspirin use has been associated with a reduced cancer incidence and fewer deaths from cancer. This study examined whether women with breast cancer prescribed aspirin postdiagnosis had improved survival.

METHODS

An observational, population cohort study was undertaken using data linkage of cancer registry, dispensed prescriptions and death records in Tayside, Scotland. All community prescriptions for aspirin in women with breast cancer were extracted and use postdiagnosis for each individual examined using Cox's proportional hazard models. The main outcome measures were all-cause mortality and breast cancer-specific mortality.

RESULTS

Four thousand six hundred and twenty-seven patients diagnosed with breast cancer between 1 January 1998 and 31 December 2008 were followed up until 28 February 2010. Median age at diagnosis was 62 (IQR 52-74). One thousand eight hundred and two (39%) deaths were recorded, with 815 (18%) attributed to breast cancer. One thousand and thirty-five (22%) patients were prescribed aspirin postdiagnosis. Such aspirin use was associated with lower risk of all-cause mortality (HR=0.53, 95% CI=0.45-0.63, P<0.001) and breast cancer-specific mortality (HR=0.42, 95% CI=0.31-0.55, P<0.001) after adjusting for age, socioeconomic status, TNM stage, tumour grade, oestrogen receptor status, surgery, radiotherapy, chemotherapy, adjuvant endocrine therapy and aspirin use prediagnosis.

CONCLUSIONS

Aspirin use postdiagnosis of breast cancer may reduce both all-cause and breast cancer-specific mortality. Further investigation seeking a causal relationship and which subgroups of patients benefit most await ongoing randomised controlled trials.

Re-expression and epigenetic modification of maspin induced apoptosis in MCF-7 cells mediated by myocardin

Breast cancer is the leading cause of cancer death in women worldwide. It is well known that oncogene activation and anti-oncogene inactivation affect the development and progression of breast cancer, but the role of oncogene activation and anti-oncogene inactivation in breast cancer is still not fully understood. We now report that maspin acts as a tumor suppressor gene to induce MCF-7 cell apoptosis. In addition, maspin promoter hypermethylation and histone hypoacetylation lead to silencing of maspin gene expression in MCF-7 cells. Moreover, DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-aza-dc) and/or the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA) strongly up-regulated the expression of maspin in MCF-7 cells. Notably, myocardin can promote the re-expression of maspin in MCF-7 cells. Luciferase assay shows that myocardin activates the transcription of maspin promoter by CArG box. More importantly, 5-aza-dc/TSA and myocardin synergetically enhance re-expression of maspin and augment maspin-mediated apoptosis in MCF-7 cells. Thus, these data reveal the new insight that myocardin meditates apoptosis in breast cancer through affecting maspin re-expression and epigenetic modification to regulate the development of breast cancer, thereby raising the possibility of its use in breast cancer therapy.

Maspin expression and melanoma progression: a matter of sub-cellular localization

Maspin, a member of the serpin family of protease inhibitors, is involved in key processes of cancer progression. Its biological activity seems to be cancer and compartment specific, with the protein acting either as a suppressor or as a tumor promoter in different cancer types. Characterization of maspin expression and its sub-cellular localization in melanoma is missing, hence, we aim to investigate its possible association with melanoma prognostic factors and disease progression. Nuclear and cytoplasmic maspin expression were evaluated on 60 nevi, 152 primary lesions, and 106 melanoma metastases using tissue microarrays and immunohistochemistry. The association between maspin immunoreactivity and patient's clinic-pathological features was evaluated. Multivariate logistic models and survival analyses were performed for maspin expression in primary melanomas. Nuclear maspin was detected in 8% nevi, 49% primary melanomas, and 28% metastases, whereas cytoplasmic maspin in 12% nevi, 18% primary lesions, and 9% metastases. In univariate analysis, nuclear maspin expression in primary melanomas was significantly associated with melanoma prognostic factors (nodular histotype, tumor thickness, mitotic rate, and ulceration) and disease stage, whereas cytoplasmic maspin was observed at higher frequency in thin superficial spreading melanomas, without mitosis. In multivariate analysis, nuclear maspin remained significantly associated with risk of developing a tumor prone to disease progression and, accordingly, with significantly shorter disease-free and overall survival. In this study, maspin was expressed at highest frequency in primary lesions and when expressed in the nuclei, was significantly associated with poor prognostic markers, melanoma recurrence, and worse survival. The present study suggests a tumor-suppressive effect of cytoplasmic maspin and a tumor-promoting effect of nuclear maspin, which open the discussion on its potential use in cancer therapy.

Nuclear location of tumor suppressor protein maspin inhibits proliferation of breast cancer cells without affecting proliferation of normal epithelial cells

Background

Maspin, which is classified as a tumor suppressor protein, is downregulated in many types of cancer. Several studies have suggested potential anti-proliferative activity of maspin as well as sensitizing activity of maspin for therapeutic cytotoxic agents in breast cancer tissue culture and animal models. All of the experimental data gathered so far have been based on studies with maspin localized cytoplasmically, while maspin in breast cancer tumor cells may be located in the cytoplasm, nucleus or both. In this study, the effect of maspin cytoplasmic and nuclear location and expression level on breast cancer proliferation and patient survival was studied.

Methods

Tissue sections from 166 patients with invasive ductal breast cancer were stained by immunohistochemistry for maspin and Ki-67 protein. The localization and expression level of maspin were correlated with estimated patient overall survival and percent of Ki-67-positive cells. In further studies, we created constructs for transient transfection of maspin into breast cancer cells with targeted cytoplasmic and nuclear location. We analyzed the effect of maspin location in normal epithelial cell line MCF10A and three breast cancer cell lines - MCF-7, MDA-MB-231 and SKBR-3 - by immunofluorescence and proliferation assay.

Results

We observed a strong positive correlation between moderate and high nuclear maspin level and survival of patients. Moreover, a statistically significant negative relationship was observed between nuclear maspin and Ki-67 expression in patients with invasive ductal breast cancer. Spearman’s correlation analysis showed a negative correlation between level of maspin localized in nucleus and percentage of Ki-67 positive cells. No such differences were observed in cells with cytoplasmic maspin. We found a strong correlation between nuclear maspin and loss of Ki-67 protein in breast cancer cell lines, while there was no effect in normal epithelial cells from breast. The anti-proliferative effect of nuclear maspin on breast cancer cells was statistically significant in comparison to cytoplasmic maspin.

Conclusions

Our results suggest that nuclear maspin localization may be a prognostic factor in breast cancer and may have a strong therapeutic potential in gene therapy. Moreover, these data provide a new insight into the role of cytoplasmic and nuclear fractions of maspin in breast cancer.

Understanding the role of ETS-mediated gene regulation in complex biological processes

Ets factors are members of one of the largest families of evolutionarily conserved transcription factors, regulating critical functions in normal cell homeostasis, which when perturbed contribute to tumor progression. The well-documented alterations in ETS factor expression and function during cancer progression result in pleiotropic effects manifested by the downstream effect on their target genes. Multiple ETS factors bind to the same regulatory sites present on target genes, suggesting redundant or competitive functions. The anti- and prometastatic signatures obtained by examining specific ETS regulatory networks will significantly improve our ability to accurately predict tumor progression and advance our understanding of gene regulation in cancer. Coordination of multiple ETS gene functions also mediates interactions between tumor and stromal cells and thus contributes to the cancer phenotype. As such, these new insights may provide a novel view of the ETS gene family as well as a focal point for studying the complex biological control involved in tumor progression. One of the goals of molecular biology is to elucidate the mechanisms that contribute to the development and progression of cancer. Such an understanding of the molecular basis of cancer will provide new possibilities for: (1) earlier detection, as well as better diagnosis and staging of disease; (2) detection of minimal residual disease recurrences and evaluation of response to therapy; (3) prevention; and (4) novel treatment strategies. Increased understanding of ETS-regulated biological pathways will directly impact these areas.

Essential role of NADPH oxidase-dependent reactive oxygen species generation in regulating microRNA-21 expression and function in prostate cancer

AIMS

Oncogenic microRNAs (miRs) promote tumor growth and invasiveness. One of these, miR-21, contributes to carcinogenesis in prostate and other cancers. In the present study, we tested the hypothesis that NADPH oxidase-dependent reactive oxygen species (ROS) regulate the expression and function of miR-21 and its target proteins, maspin and programmed cell death 4 (PDCD4), in prostate cancer cells.

RESULTS

The highly aggressive androgen receptor negative PC-3M-MM2 prostate cancer cells demonstrated high expression of miR-21 and p47(phox) (an essential subunit of NADPH oxidase). Using loss-of-function strategy, we showed that transfection of PC-3M-MM2 cells with anti-miR-21- and p47(phox) siRNA (si-p47(phox)) led to reduced expression of miR-21 with concurrent increase in maspin and PDCD4, and decreased the invasiveness of the cells. Tail-vein injections of anti-miR-21- and si-p47(phox)-transfected PC-3M-MM2 cells in severe combined immunodeficient mice reduced lung metastases. Clinical samples from patients with advanced prostate cancer expressed high levels of miR-21 and p47(phox), and low expression of maspin and PDCD4. Finally, ROS activated Akt in these cells, the inhibition of which reduced miR-21 expression.

INNOVATION

The levels of NADPH oxidase-derived ROS are high in prostate cancer cells, which have been shown to be involved in their growth and migration. This study demonstrates that ROS produced by this pathway is essential for the expression and function of an onco-miR, miR-21, in androgen receptor-negative prostate cancer cells.

CONCLUSION

These data demonstrate that miR-21 is an important target of ROS, which contributes to the highly invasive and metastatic phenotype of prostate cancer cells.

Maspin influences response to doxorubicin by changing the tumor microenvironment organization

Altered degradation and deposition of extracellular matrix are hallmarks of tumor progression and response to therapy. From a microarray supervised analysis on a dataset of chemotherapy-treated breast carcinoma patients, maspin, a member of the serpin protease inhibitor family, has been the foremost variable identified in non-responsive versus responsive tumors. Accordingly, in a series of 52 human breast carcinomas, we detected high maspin expression in tumors that progressed under doxorubicin (DXR)-based chemotherapy. Our analysis of the role of maspin in response to chemotherapy in human MCF7 and MDAMB231 breast and SKOV3 ovarian carcinoma cells transfected to overexpress maspin and injected into mice showed that maspin overexpression led to DXR resistance through the maspin-induced collagen-enriched microenvironment and that an anti-maspin neutralizing monoclonal antibody reversed the collagen-dependent DXR resistance. Impaired diffusion and decreased DXR activity were also found in tumors derived from Matrigel-embedded cells, where abundant collagen fibers characterize the tumor matrix. Conversely, liposome-based DXR reached maspin-overexpressing tumor cells despite the abundant extracellular matrix and was more efficient in reducing tumor growth. Our results identify maspin-induced accumulation of collagen fibers as a cause of disease progression under DXR chemotherapy for breast cancer. Use of a more hydrophilic DXR formulation or of a maspin inhibitor in combination with chemotherapy holds the promise of more consistent responses to maspin-overexpressing tumors and dense-matrix tumors in general.

Identification of an intrinsic determinant critical for maspin subcellular localization and function

Maspin, a multifaceted tumor suppressor, belongs to the serine protease inhibitor superfamily, but only inhibits serine protease-like enzymes such as histone deacetylase 1 (HDAC1). Maspin is specifically expressed in epithelial cells and it is differentially regulated during tumor progression. A new emerging consensus suggests that a shift in maspin subcellular localization from the nucleus to the cytoplasm stratifies with poor cancer prognosis. In the current study, we employed a rational mutagenesis approach and showed that maspin reactive center loop (RCL) and its neighboring sequence are critical for maspin stability. Further, when expressed in multiple tumor cell lines, single point mutation of Aspartate(346) (D(346)) to Glutamate (E(346)), maspin(D346E), was predominantly nuclear, whereas wild type maspin (maspin(WT)) was both cytoplasmic and nuclear. Evidence from cellular fractionation followed by immunological and proteomic protein identification, combined with the evidence from fluorescent imaging of endogenous proteins, fluorescent protein fusion constructs, as well as bimolecular fluorescence complementation (BiFC) showed that the increased nuclear enrichment of maspin(D346E) was, at least in part, due to its increased affinity to HDAC1. Maspin(D346E) was also more potent than maspin(WT) as an HDAC inhibitor. Taken together, our evidence demonstrates that D(346) is a critical cis-element in maspin sequence that determines the molecular context and subcellular localization of maspin. A mechanistic model derived from our evidence suggests a new window of opportunity for the development of maspin-based biologically competent HDAC inhibitors for cancer treatment.

Update of the human and mouse SERPIN gene superfamily

The serpin family comprises a structurally similar, yet functionally diverse, set of proteins. Named originally for their function as serine proteinase inhibitors, many of its members are not inhibitors but rather chaperones, involved in storage, transport, and other roles. Serpins are found in genomes of all kingdoms, with 36 human protein-coding genes and five pseudogenes. The mouse has 60 Serpin functional genes, many of which are orthologous to human SERPIN genes and some of which have expanded into multiple paralogous genes. Serpins are found in tissues throughout the body; whereas most are extracellular, there is a class of intracellular serpins. Serpins appear to have roles in inflammation, immune function, tumorigenesis, blood clotting, dementia, and cancer metastasis. Further characterization of these proteins will likely reveal potential biomarkers and therapeutic targets for disease.

Serpin B5 is a CEA-interacting biomarker for colorectal cancer

Serpin B5 is a candidate tumour suppressor, but its oncogenic activity has also been reported. Its function may be affected by protein interactions. The aim of this study was to assess the relationship between serpin B5 and carcinoembryonic antigen (CEA) expression in colorectal cancer (CRC). We also analysed the clinicopathological significance of serpin B5 expression in patients with CRC. Downregulation of serpin B5 was identified in a CEA-suppressed LoVo cell line using two-dimensional gel electrophoresis (2-DE) and matrix-associated laser desorption ionisation-mass spectrometry (MALDI-MS). The specific interaction and co-localisation of serpin B5 with CEA were confirmed by co-immunoprecipitation and confocal microscopy. Western blot analysis and ELISAs revealed significant positive correlations between levels of serpin B5 and CEA in human colon cancer cell lines and in the blood of patients with CRC. Tissue expression of serpin B5 in 377 patients with CRC was significantly associated with serum CEA, histological grade, stage, lymph node metastasis, lymphatic and perineural invasion, and infiltrative border. Strong expression of serpin B5 was also associated with a reduced DFS (p = 0.001) and OS (p = 0.017). Together, these findings describe a relationship between serpin B5 and CEA expression in CRC. Strong expression of serpin B5 was associated with a worse prognosis in patients with CRC and its expression may correlate with CEA levels in CRC.

Decreased levels of miR-224 and the passenger strand of miR-221 increase MBD2, suppressing maspin and promoting colorectal tumor growth and metastasis in mice

BACKGROUND & AIMS

Little is known about functions of microRNA (miR) passenger strands (miR*) or their roles in tumor development or progression. We screened for miRs and miR* with levels that were altered in metastatic colorectal cancer (CRC) cells and human tumor samples and investigated their targets and effects on cell function and tumor progression in mice.

METHODS

We performed array-based profile analysis to identify miRs with levels that were increased more than 2-fold in metastatic (SW620) CRC cells compared with nonmetastatic (SW480) cells. Quantitative polymerase chain reaction and in situ hybridization analyses were used to measure miRNA levels in CRC cell lines and human tumor samples. We used miRNA duplex mimics or inhibitors to increase and decrease levels of miRNA in CRC cells and assessed their activities and ability to form metastatic xenograft tumors in nude mice.

RESULTS

Levels of miR-221* and miR-224 were reduced in metastatic compared with nonmetastatic CRC cells; levels in human tumor samples correlated inversely with tumor stage and metastasis to lymph nodes as well as patient survival times. SW480 cells transfected with miR-221* or miR-224 inhibitors had increased motility in vitro compared with SW480 control cells and formed larger, more metastatic tumors when injected into mice. SW620 cells transfected with miR-221* or miR-224 mimics had reduced migration and motility in vitro and formed smaller tumors with fewer metastases in mice compared with control SW620 cells. We identified the 3' untranslated region of MBD2 messenger RNA as a target of miR-221* and miR-224. MBD2 silences the gene encoding maspin, a suppressor of metastasis. In CRC cells, we found that miR-221* and miR-224 increase the expression of maspin through MBD2 down-regulation.

CONCLUSIONS

In metastatic CRC cells, reduced levels of miR-221* and miR-224 increase levels of MBD2, thereby decreasing expression of the metastasis suppressor maspin. Increased activities of miR-221* and miR-224 reduce growth and metastasis of CRC xenograft tumors in mice; these miRs might be developed as therapeutic reagents or biomarkers of CRC progression.

Maspin is a marker for early recurrence in primary stage III and IV colorectal cancer

Background:

Little is known about the factors that drive metastasis formation in colorectal cancer (CRC). Here, we set out to identify genes and proteins in patients with colorectal liver metastases that correlate with early disease recurrence. Such factors may predict a propensity for metastasis in earlier stages of CRC.

Methods:

Gene expression profiling and proteomics were used to identify differentially expressed genes/proteins in resected liver metastases that recurred within 6 months following liver surgery vs those that did not recur for >24 months. Expression of the identified genes/proteins in stage II (n=243) and III (n=176) tumours was analysed by immunohistochemistry on tissue microarrays. Correlation of protein levels with stage-specific outcome was assessed by uni- and multivariable analyses.

Results:

Both gene expression profiling and proteomics identified Maspin to be differentially expressed in colorectal liver metastases with early (<6 months) and prolonged (>24 months) time to recurrence. Immunohistochemical analysis of Maspin expression on tumour sections revealed that it was an independent predictor of time to recurrence (log-rank P=0.004) and CRC-specific survival (P=0.000) in stage III CRC. High Maspin expression was also correlated with mucinous differentiation. In stage II CRC patients, high Maspin expression did not correlate with survival but was correlated with a right-sided tumour location.

Conclusion:

High Maspin expression correlates with poor outcome in CRC after spread to the local lymph nodes. Therefore, Maspin may have a stage-specific function possibly related to tumour cell dissemination and/or metastatic outgrowth.

Control of metastatic progression by microRNA regulatory networks

Aberrant microRNA (miRNA) expression is a defining feature of human malignancy. Specific miRNAs have been identified as promoters or suppressors of metastatic progression. miRNAs control metastasis through divergent or convergent regulation of metastatic gene pathways. Some miRNA regulatory networks govern cell-autonomous cancer phenotypes, whereas others modulate the cell-extrinsic composition of the metastatic microenvironment. The use of small RNAs as probes into the molecular and cellular underpinnings of metastasis holds promise for the identification of candidate genes for potential therapeutic intervention.

Maspin expression in the invasive margin of primary melanomas may reflect an aggressive tumor phenotype

BACKGROUND

The role of maspin has been discussed controversially in different tumors. In the majority of malignant tumors, maspin seems to act as a tumor suppressor. However, data about maspin expression as well as its function in melanoma are very inconsistent.

OBJECTIVE

To investigate the expression of maspin in melanomas and to correlate the intensity of maspin staining with prognostic parameters of the tumor and with progression-free and overall survival.

PATIENTS AND METHODS

Primary melanomas from 47 patients were investigated for maspin expression using immunohistochemistry.

RESULTS

Maspin was heterogeneously expressed predominantly in the cytoplasm of melanoma cells. Maspin staining intensity in the invasive part of the tumor correlated with parameters of prognosis such as Clark level (p  =  0.05), tumor thickness (p  =  0.002) and stage of disease (p  =  0.023). Maspin staining intensity in the invasive front of the tumor significantly correlated with death from disease (p  =  0.007) and shortened overall survival (p  =  0.007).

CONCLUSIONS

In accordance with data concerning maspin expression in colorectal cancers, the expression of this protein in the invasive front of primary melanomas seems to correlate with local infiltration and tumor aggressiveness. Strong maspin expression in the invasive margin of primary melanomas therefore might reflect an aggressive tumor phenotype.

Maspin: molecular mechanisms and therapeutic implications

Maspin, a non-inhibitory member of the serine protease inhibitor superfamily, has been characterized as a tumor suppressor gene in multiple cancer types. Among the established anti-tumor effects of Maspin are the inhibition of cancer cell invasion, attachment to extracellular matrices, increased sensitivity to apoptosis, and inhibition of angiogenesis. However, while significant experimental data support the role of Maspin as a tumor suppressor, clinical data regarding the prognostic implications of Maspin expression have led to conflicting results. This highlights the need for a better understanding of the context dependencies of Maspin in normal biology and how these are perturbed in the context of cancer. In this review, we outline the regulation and roles of Maspin in normal and developmental biology while discussing novel evidence and emerging theories related to its functions in cancer. We provide insight into the immense therapeutic potential of Maspin and the challenges related to its successful clinical translation.

Elevated maspin expression is associated with better overall survival in esophageal squamous cell carcinoma (ESCC)

Tumor suppressor maspin is a differentially regulated gene in the progression of many types of cancer. While the biological function of maspin in blocking tumor invasion and metastasis is consistent with the loss of maspin expression at the late stage of tumor progression, the differential expression and the biological significance of maspin in early stage of tumor progression appear to be complex and remain to be elucidated. In the current study, we examined the expression of maspin in 84 esophageal squamous cell carcinoma (ESCC) cases (stages I–III) and 55 non-tumor adjacent esophageal tissue specimens by immunohistochemical (IHC) staining. The correlation of maspin with clinicopathological parameters was analyzed. Compared to normal esophageal squamous tissue where 80% (47/55) of the cases expressed maspin at a low to moderate level, all ESCC specimens (100% (84/84)) were positive for maspin expression at a moderate to high level. ESCC with low or moderate maspin expression had significantly shorter postoperative survival rates compared to those that had high maspin expression (p<0.001). Since the correlation of maspin with ESCC histology and the correlation of maspin with ESCC prognosis seem to be at odds, we further investigated the biological function of maspin in ESCC using the established ESCC cell lines. The expression of maspin in five human esophageal squamous cancer cell lines (T12, E450, KYSE150, EC109, and KYSE510) was examined by the Western blot. ESCC cell line KYSE510 that did not express maspin and was stably transfected by maspin cDNA or an empty vector. The resulting transfected cells were characterized in vitro. Maspin expression significantly inhibited cell proliferation, motility and matrigel invasion. Taken together, our data suggest that the transient up-regulation of maspin in the early development of ESCC may be a defense mechanism against further transition towards more malignant phenotypes, ultimately slowing down ESCC tumor progression.

Isolation and characterization of two novel serpins from the tick Rhipicephalus haemaphysaloides

Two novel serpins with anti-chymotrypsin activity, RHS-1 and RHS-2, were identified in the tick Rhipicephalus haemaphysaloides. The complementary cDNA sequence of RHS-1 was 1286 base pairs (bp) and encoded a deduced 403-amino acid protein with a signal peptide, whereas that of RHS-2 was 1682bp and encoded a deduced 380-amino acid protein with no signal peptide. Although both RHS-1 and RHS-2 exhibited high sequence similarities to known serpins from other ticks, the level of similarity at the amino acid level between the 2 serpins characterized here was only 32.5%. Salivary gland-specific expression of RHS-1 and midgut-specific expression of RHS-2 were found by Western blot using the relevant antiserum. We tested the ability of purified recombinant rRHS-1 and rRHS-2 to inhibit various serine proteases and found that both significantly inhibited chymotrypsin (95.6% and 94.2%, respectively). We further demonstrated that RHS-1, but not RHS-2 exhibited anticoagulation activity, based on activated partial thromboplastin time (APTT). Disruption of the genes encoding the 2 serpins with RNA interference (RNAi) led to a significant decrease in tick attachment and engorgement rates. These results indicate that RHS-1 and RHS-2 are 2 novel serpins with anti-chymotrypsin activity that are involved in blood feeding of R. haemaphysaloides.

A proteomic study of potential VEGF-C-associated proteins in bladder cancer T24 cells

Background

Overexpression of vascular endothelial growth factor-C (VEGF-C) has been found to play an important role in malignant progression of various cancer cells, in addition to lymphangiogenesis. However, the mechanisms involved are still largely unknown. Our early research has confirmed that the expression of VEGF-C in bladder cancer was markedly higher than that in normal bladder tissues. VEGF-C can also obviously promote proliferation and invasion of bladder cancer T24 cells. In the present work, we attempted to use proteomic analysis to screen out potential VEGF-C-associated proteins involved in malignant progression of the bladder cancer T24 cells.

Material/Methods

Lentivirus vector-based RNA interference (RNAi) was employed to diminish VEGF-C expression of bladder cancer T24 cells. Then we performed comparative proteome analysis to explore differentially expressed proteins in T24 cells with and without VEGF-C siRNA, by two-dimensional difference gel electrophoresis (2D-DIGE).

Results

Twenty-three proteins were identified. Some proteins (matrix metalloproteinase-9, Keratin 8, Serpin B5, Annexin A8) with significant differences were further confirmed by Western blotting.

Conclusions

The 23 potential VEGF-C-associated proteins identified in our study provide us with further insights into the mechanism of VEGF-C promoting malignant progression of bladder cancer cells.

A versatile monoclonal antibody specific to human SERPINB5

Maspin (SERPINB5) is a member of the Clade B subgroup of the large superfamily of serine protease inhibitors. It is proposed that maspin is a tumor suppressor; however, its molecular role remains to be elucidated. Here we report the characterization of a mouse monoclonal antibody directed against human maspin. This antibody, 16F7, recognizes maspin in both its native and denatured form, unlike several other commercial antibodies tested in this study. It will be a useful and versatile tool for future analyses of the biological function of maspin.

Role of maspin in cancer

Maspin (mammary serine protease inhibitor), is a member of the serine protease inhibitor/non-inhibitor superfamily. Its expression is down-regulated in breast, prostate, gastric and melanoma cancers but over-expressed in pancreatic, gallbladder, colorectal, and thyroid cancers suggesting that maspin may play different activities in different cell types. However, maspin expression seems to be correlated with better prognosis in prostate, bladder, lung, gastric, colorectal, head and neck, thyroid and melanoma cancer. In breast and ovarian cancer maspin significance is associated with its subcellular localization: nucleus maspin expression correlates with a good prognosis, whilst in pancreatic cancer it predicts a poor prognosis. Since tumor metastasis requires the detachment and invasion of tumor cells through the basement membrane and stroma, a selectively increased adhesion by the presence of maspin may contribute to the inhibition of tumor metastasis. Furthermore the different position of maspin inside the cell or its epigenetic modifications may explain the different behavior of the expression of maspin between tumors. The expression of maspin might be useful as a prognostic and possibly predictive factor for patients with particular types of cancer and data can guide physicians in selecting therapy. Its expression in circulating tumor cells especially in breast cancer, could be also useful in clinical practice along with other factors, such as age, comorbidities, blood examinations in order to select the best therapy to be carried out. Focusing on the malignancies in which maspin showed a positive prognostic value, therapeutic approaches studied so far aimed to re-activate a dormant tumor suppressor gene by designed transcription factors, to hit the system that inhibits the expression of maspin, to identify natural substances that can determine the activation and the expression of maspin or possible “molecules binds” to introduce maspin in cancer cell and gene therapy capable of up-regulating the maspin in an attempt to reduce primarily the risk of metastasis.

Further studies in these directions are necessary to better define the therapeutic implication of maspin.

Tumor-suppressive maspin functions as a reactive oxygen species scavenger: importance of cysteine residues

Maspin is a member of the serine protease inhibitor (serpin) superfamily and displays tumor-suppressing activity by controlling cell migration, proliferation, apoptosis, and adhesion. Here, we provide evidence that maspin acts as a reactive oxygen species (ROS) scavenger through oxidation of three structurally exposed cysteine thiols to sulfenic acid. Ablation of these cysteine residues in maspin resulted in a significant increase in total ROS production in mouse mammary TM40D cells. Also, cells containing a triple-cysteine mutant of maspin showed elevated ERK1/2 activity, a downstream target of ROS, and enhanced proliferation and colony formation. These findings establish a novel mechanism by which maspin utilizes its cysteine thiols to inhibit oxidative stress and cell growth.

Expression of the homeostasis-related markers, maspin, heat shock proteins 70 & 90, glutathione S-transferase, aquaporin 5 and NF-kB in young and old labial and palatal salivary glands

Intraoral salivary glands undergo remarkable age-related morphologic changes. This study investigated the expression of a panel of molecular markers known for cellular homeostatic activity, dependent on age and location of the salivary glands. Samples taken from healthy subjects were classified according to age ("young" <45 years, n=51, and "old" ≥60 years, n=45) and location (lip, n=47 and palate, n=49). They were immunohistochemically stained for mammary serine protease inhibitor (maspin), heat shock protein (HSP)70, HSP90, glutathione S-transferase (GST), aquaporine5 (AQP5), and nuclear factor kappa-B (NF-κB) for assessment of their expression in acini and ducts, and in cytoplasmic and nuclear compartments. Results were expressed as the mean percentage of positively stained component per age group, gland location and type of cell and cellular compartment. Statistical analysis was performed by two-way ANOVA and crosstabs. The expression of maspin was lower in the old group in both the palatal and labial glands (acini and ducts, cytoplasm and nuclei) compared to the young group (p<0.05). In both age groups, when compared to labial glands, palatal glands exhibited higher expression of HSP70 (p<0.05) and lower expression of AQP5 (p<0.001) and NF-κB (p=0.018). Collectively, the low expression of factors capable of preserving cellular homeostasis (i.e., maspin and AQP5) vis-à-vis a high expression of factors that are also related to cell survival (i.e., HSPs) that was demonstrated in the old palatal glands may point to their high vulnerability to undergo selective phenotypic changes.

Tumor-infiltrating immune cells promoting tumor invasion and metastasis: existing theories

It is a commonly held belief that infiltration of immune cells into tumor tissues and direct physical contact between tumor cells and infiltrated immune cells is associated with physical destructions of the tumor cells, reduction of the tumor burden, and improved clinical prognosis. An increasing number of studies, however, have suggested that aberrant infiltration of immune cells into tumor or normal tissues may promote tumor progression, invasion, and metastasis. Neither the primary reason for these contradictory observations, nor the mechanism for the reported diverse impact of tumor-infiltrating immune cells has been elucidated, making it difficult to judge the clinical implications of infiltration of immune cells within tumor tissues. This mini-review presents several existing hypotheses and models that favor the promoting impact of tumor-infiltrating immune cells on tumor invasion and metastasis, and also analyzes their strength and weakness.

Cancer cell resistance to aurora kinase inhibitors: identification of novel targets for cancer therapy

Drug resistance is the major obstacle to successful cancer therapy. Our study focuses on resistance to Aurora kinase inhibitors tested as anti-cancer drugs in clinical trials. We have used 2D electrophoresis in the pH ranges of 4-7 and 6-11 followed by protein identification using MALDI-TOF/TOF to compare the protein composition of HCT116 colon cancer cells either sensitive to CYC116 and ZM447439 inhibitors or resistant toward these drugs. The analysis also included p53(+/+) and p53(-/-) phenotypes of HCT116 cells. Our findings demonstrate that platelet-activating factor acetylhydrolase and GTP-binding nuclear protein Ran contribute to the development of resistance to ZM447439 only where resistance is related to p53. On the other hand, serine hydroxymethyltransferase was found to promote the tumor growth in cells resistant to CYC116 without the influence of p53. Computer modeling of interaction networks highlighted a direct link of the p53-independent mechanism of resistance to CYC116 with autophagy. Importantly, serine hydroxymethyltransferase, serpin B5, and calretinin represent the target proteins that may help overcome resistance in combination therapies. In addition, serpin B5 and calretinin appear to be candidate biomarkers that may be accessible in patients for monitoring of cancer therapy with ease.

Writing and rewriting the epigenetic code of cancer cells: from engineered proteins to small molecules

The epigenomic era has revealed a well-connected network of molecular processes that shape the chromatin landscape. These processes comprise abnormal methylomes, transcriptosomes, genome-wide histone post-transcriptional modifications patterns, histone variants, and noncoding RNAs. The mapping of these processes in large scale by chromatin immunoprecipitation sequencing and other methodologies in both cancer and normal cells reveals novel therapeutic opportunities for anticancer intervention. The goal of this minireview is to summarize pharmacological strategies to modify the epigenetic landscape of cancer cells. These approaches include the use of novel small molecule inhibitors of epigenetic processes specifically deregulated in cancer cells and the design of engineered proteins able to stably reprogram the epigenetic code in cancer cells in a way that is similar to normal cells.

The pro-metastatic role of bone marrow-derived cells: a focus on MSCs and regulatory T cells

Several bone marrow-derived cells have been shown to promote tumour growth and progression. These cells can home to the primary tumour and become active components of the tumour microenvironment. Recent studies have also identified bone marrow-derived cells—such as mesenchymal stem cells and regulatory T cells—as contributors to cancer metastasis. The innate versatility of these cells provides diverse functional aid to promote malignancy, ranging from structural support to signal-mediated suppression of the host immune response. Here, we review the role of mesenchymal stem cells and regulatory T cells in cancer metastasis. A better understanding of the bipolar nature of these bone marrow-derived cells in physiological and malignant contexts could pave the way for new therapeutics against metastatic disease.

Snail transcription factor negatively regulates maspin tumor suppressor in human prostate cancer cells

BACKGROUND

Maspin, a putative tumor suppressor that is down-regulated in breast and prostate cancer, has been associated with decreased cell motility. Snail transcription factor is a zinc finger protein that is increased in breast cancer and is associated with increased tumor motility and invasion by induction of epithelial-mesenchymal transition (EMT). We investigated the molecular mechanisms by which Snail increases tumor motility and invasion utilizing prostate cancer cells.

METHODS

Expression levels were analyzed by RT-PCR and western blot analyses. Cell motility and invasion assays were performed, while Snail regulation and binding to maspin promoter was analyzed by luciferase reporter and chromatin immunoprecipitation (ChIP) assays.

RESULTS

Snail protein expression was higher in different prostate cancer cells lines as compared to normal prostate epithelial cells, which correlated inversely with maspin expression. Snail overexpression in 22Rv1 prostate cancer cells inhibited maspin expression and led to increased migration and invasion. Knockdown of Snail in DU145 and C4-2 cancer cells resulted in up-regulation of maspin expression, concomitant with decreased migration. Transfection of Snail into 22Rv1 or LNCaP cells inhibited maspin promoter activity, while stable knockdown of Snail in C4-2 cells increased promoter activity. ChIP analysis showed that Snail is recruited to the maspin promoter in 22Rv1 cells.

CONCLUSIONS

Overall, this is the first report showing that Snail can negatively regulate maspin expression by directly repressing maspin promoter activity, leading to increased cell migration and invasion. Therefore, therapeutic targeting of Snail may be useful to re-induce expression of maspin tumor suppressor and prevent prostate cancer tumor progression.

Targeting serous epithelial ovarian cancer with designer zinc finger transcription factors

Ovarian cancer is the leading cause of death among gynecological malignancies. It is detected at late stages when the disease is spread through the abdominal cavity in a condition known as peritoneal carcinomatosis. Thus, there is an urgent need to develop novel therapeutic interventions to target advanced stages of ovarian cancer. Mammary serine protease inhibitor (Maspin) represents an important metastasis suppressor initially identified in breast cancer. Herein we have generated a sequence-specific zinc finger artificial transcription factor (ATF) to up-regulate the Maspin promoter in aggressive ovarian cancer cell lines and to interrogate the therapeutic potential of Maspin in ovarian cancer. We found that although Maspin was expressed in some primary ovarian tumors, the promoter was epigenetically silenced in cell lines derived from ascites. Transduction of the ATF in MOVCAR 5009 cells derived from ascitic cultures of a TgMISIIR-TAg mouse model of ovarian cancer resulted in tumor cell growth inhibition, impaired cell invasion, and severe disruption of actin cytoskeleton. Systemic delivery of lipid-protamine-RNA nanoparticles encapsulating a chemically modified ATF mRNA resulted in inhibition of ovarian cancer cell growth in nude mice accompanied with Maspin re-expression in the treated tumors. Gene expression microarrays of ATF-transduced cells revealed an exceptional specificity for the Maspin promoter. These analyses identified novel targets co-regulated with Maspin in human short-term cultures derived from ascites, such as TSPAN12, that could mediate the anti-metastatic phenotype of the ATF. Our work outlined the first targeted, non-viral delivery of ATFs into tumors with potential clinical applications for metastatic ovarian cancers.

The Role of Neutrophil Estrogen Receptor Status on Maspin Synthesis via Nitric Oxide Production in Human Breast Cancer

Purpose

Estrogen, through its binding to nuclear estrogen receptor (ER), has been implicated in the development of human breast cancer. The presence or absence of ER in breast lesions has been used to classify breast cancer into ER+ or ER- type. Maspin, an anti-breast cancer protein produced in normal mammary cells, has also been reported to control the condition. Studies have been conducted to determine the role of ER+ and ER- status in neutrophils in the synthesis of maspin in human breast cancer.

Methods

Maspin presence was determined by enzyme linked immunosorbent assay, while nitric oxide (NO) level was determined using the methemoglobin method.

Results

Scatchard plots of the equilibrium binding of estrogen demonstrated the presence of 4.18×10⁷ receptors per normal neutrophil and 2.46×10⁷ receptors per ER+ neutrophil with a similar dissociation constant (0.926 nM). The ER- type showed nonspecific estrogen binding only. At 0.6 nM estrogen, NO synthesis was maximally increased to 1.829 and 0.887 µM NO/10⁹ cells at 4 hours in normal and ER+ neutrophils respectively, with synthesis of 2.383 and 1.422 nM maspin in normal and ER+ neutrophils respectively. Estrogen failed to produce these effects in ER- neutrophils.

Conclusion

ER status in neutrophils determined maspin synthesis in breast cancer through the stimulation of NO synthesis. Neutrophils with ER- status which do not produce any maspin when treated with estrogen, might imply a worse prognostic outcome in ER- breast cancer due to the lack of anti-breast cancer protein synthesis.

Expression of maspin in non-small cell lung cancer and its relationship to vasculogenic mimicry

Maspin belongs to the serine protease inhibitor (serpin) family and has been proven to be a suppressor of tumor growth and metastasis in many types of tumors. The purpose of this study was to investigate the expression of maspin in non-small cell lung cancer (NSCLC) and its relationship to vasculogenic mimicry (VM). A total of 160 specimens of NSCLC were involved in this study and 20 specimens of normal lung tissue served as controls. VM, microvessel density (MVD) and the expression of maspin were detected by using immunohistochemical staining. The results showed that the positive rates of maspin and VM in the NSCLC group were 48.1% (77/160) and 36.9% (59/160), respectively, which were significantly different from those in the control group with the positive rates of maspin and VM being 100% and 0% respectively (P<0.05). VM, MVD and the expression level of maspin were significantly related to tumor differentiation, lymph node metastasis, clinical stages and postoperative survival time (all P<0.05). The maspin expression in patients with squamous cell carcinoma was significantly higher than that in those with adenocarcinoma (P<0.05). The maspin expression was negatively correlated with VM and MVD, and there was a positive correlation between VM and MVD. Maspin-negative expression, VM and high MVD score were negatively related to the 5-year-survival rate. PTNM stages, VM, MVD and maspin expression were independent prognostic factors for NSCLC (P<0.05). It was suggested that the loss of expression of maspin may participate in the invasion and metastasis of NSCLC and it has a positive relationship to VM in NSCLC. Combined detection of maspin, VM and MVD may help predict the progression and prognosis of NSCLC.

Cathepsin E, maspin, Plk1, and survivin are promising prognostic protein markers for progression in non-muscle invasive bladder cancer

Bladder cancer is a common cancer with particularly high recurrence after transurethral resection. In this study, we investigated the prognostic value of the protein expression of cathepsin E, maspin, polo-like kinase 1 (Plk1), and survivin in patients with stage Ta and T1 urothelial carcinomas. Transcripts from the four genes encoding these proteins were previously included in gene expression signatures for outcome prediction for Ta/T1 bladder cancer. We used three different tissue microarrays with 693 non-muscle invasive urothelial carcinomas from Danish, Swedish, and Spanish patient cohorts with long-term follow-up. Protein expression was measured by immunohistochemistry, and antibody specificity was validated by Western blotting. In the Danish patient cohort, we found the expression of cathepsin E, maspin, Plk1, and survivin to be significantly associated with progression to stage T2 to T4 bladder cancer (for each marker: log-rank test; P < 0.001). Multivariate Cox regression analysis identified cathepsin E (P < 0.001), Plk1 (P = 0.021), maspin (P = 0.001), and survivin (P = 0.001) as independent prognostic markers. Furthermore, maspin, survivin, and cathepsin E expression significantly subgrouped patients already stratified by European Organization for Research and Treatment of Cancer risk scores. Finally, we successfully validated the results in tumors from 410 patients from both Sweden and Spain. We conclude that all four protein markers may have prognostic value in non-muscle invasive bladder cancer for guiding optimal treatment of patients. Additional prospective studies are needed for further validation of the clinical relevance of this marker panel.

Tyrosine phosphorylation plays a role in increasing maspin protein levels and its cytoplasmic accumulation

Maspin is a tumor suppressor with many biological activities, multiple ligands and different subcellular localizations. Its underlying molecular mechanism remains elusive. We hypothesized that phosphorylation might regulate maspin localization and function. Using two-dimensional gel electrophoresis with different focusing power followed by Western blot we identified four different maspin forms with the same molecular weight (42 kDa), but different isoelectric points. Three of these forms were sensitive to acidic phosphatase treatment, suggesting that they are phosphorylated. Sodium peroxidovanadate treatment, a protein-tyrosine phosphatase inhibitor, resulted in a rapid increase in maspin protein levels and cytoplasmic accumulation. These data show that there are three different maspin tyrosine phosphoforms. Inhibition of tyrosine phosphatases increased maspin protein levels and leads to its cytoplasmic accumulation.

Prognostic value of nuclear maspin expression for adjuvant 5-fluorouracil-based chemotherapy in advanced gastric cancer

To assess the prognostic and predictive value of maspin expression for the clinical response to 5-fluorouracil (5-FU)-based chemotherapy in advanced gastric cancer (GC) patients, the expression of maspin in primary tumors from 127 patients with advanced GC was examined using immunohistochemistry. Of the 127 patients, 74 were treated with surgery alone and 53 received additional adjuvant 5-FU-based chemotherapy. Nuclear and cytoplasmic maspin expression was observed in 46.5 (59/127) and 68.5% (87/127) of patients, respectively. Nuclear maspin immunoreactivity was significantly associated with larger tumor size (p=0.036), the depth of tumor invasion (p=0.02) and lymph node metastasis (p=0.002). Cytoplasmic maspin immunoreactivity was associated with tumor cell differentiation but not with the other clinicopathological variables. Nuclear maspin immunoreactivity had a significant association with overall survival (OS). Among the nuclear maspin-expressing patients, those who were treated with 5-FU-based adjuvant chemotherapy showed significantly longer OS than those without chemotherapy (p=0.0004). In conclusion, nuclear maspin expression is associated with adverse clinical outcomes in patients with advanced GC. Patients with positive nuclear maspin expression may be more responsive to adjuvant 5-FU chemotherapy.

S-glutathionylated serine proteinase inhibitors as plasma biomarkers in assessing response to redox-modulating drugs

Many cancer drugs impact cancer cell redox regulatory mechanisms and disrupt redox homeostasis. Pharmacodynamic biomarkers that measure therapeutic efficacy or toxicity could improve patient management. Using immunoblot analyses and mass spectrometry, we identified that serpins A1 and A3 were S-glutathionylated in a dose- and time-dependent manner following treatment of mice with drugs that alter reactive oxygen or nitrogen species. Tandem mass spectrometry analyses identified Cys(256) of serpin A1 and Cys(263) of serpin A3 as the S-glutathionylated residues. In human plasma from cancer patients, there were higher levels of unmodified serpin A1 and A3, but following treatments with redox active drugs, relative S-glutathionylation of these serpins was higher in plasma from normal individuals. There is potential for S-glutathionylated serpins A1 and A3 to act as pharmacodynamic biomarkers for evaluation of patient response to drugs that target redox pathways.

Avian SERPINB11 gene: a marker for ovarian endometrioid cancer in chickens

As serine and cysteine proteinase inhibitors, serpins, such as SERPINB5, cause ovarian, colorectal and pancreatic adenocarcinomas. We identified SERPINB11 as a novel estrogen-induced gene in chickens during oviduct development. The chicken is a unique animal model for research on human ovarian cancer, because it spontaneously develops epithelial cell-derived ovarian cancer as in women. Therefore, this study investigated the expression pattern, CpG methylation status, and miRNA regulation of the SERPINB11 gene in normal and cancerous ovaries from chickens. Our results indicate that SERPINB11 is most abundant in the glandular epithelium of endometrioid adenocarcinoma of cancerous, but not normal, ovaries of hens. In addition, bisulfite sequencing revealed that about 30% of -110 CpG sites are methylated in ovarian cancer cells, whereas -110 CpG sites are demethylated in normal ovarian cells. Next, we determined whether miR-1582 influences SERPINB11 expression via its 3'UTR and found that it does not directly target the 3'UTR of SERPINB11 mRNA. Therefore, it is unlikely that post-transcriptional regulation influences SERPINB11 expression in the chicken ovary. On the other hand, in human ovarian cancer cells such as OVCAR-3, SKOV-3 and PA-1 cells, immunoreactive SERPINB11 protein was predominant in the cytoplasm and had a similar expression pattern to that in chicken ovarian cancer cells. Collectively, these results suggest that SERPINB11 is a biomarker for chicken ovarian endometrioid carcinoma that could be used for diagnosis and monitoring effects of therapies for the disease in women.

Maspin expression in epithelial skin tumours: an immunohistochemical study

BACKGROUND

Maspin is a member of the serpin family of protease inhibitors and is thought to inhibit carcinoma invasion, metastasis, angiogenesis and induce apoptosis.

AIM

The aim of this work is to investigate maspin expression in cutaneous basal and squamous cell carcinomas by means of immunohistochemistry.

MATERIALS AND METHODS

This study was carried out on 43 patients, 25 basal cell carcinoma (BCC) and 18 squamous cell carcinoma (SCC) together with ten apparently healthy volunteers as a control group.

RESULTS

There was a significant difference between the malignant and control groups regarding maspin expression since all control cases showed maspin expression compared to 60.5% (26/43) positivity in malignant cases. Maspin positive expression tended to be of higher percentage in SCC (77.8%) compared to BCC (48%) (P = 0.06) and the strong intensity of maspin was also significantly in favour of SCC compared to BCC (P = 0.02). The staining of both the cytoplasm and nuclei was seen in 27.7% of SCC and 12% of BCC and was significantly in favour of older age group (P = 0.02) and the adenoid variant (P = 0.04) of the latter.

CONCLUSIONS

Maspin is associated with terminal squamous differentiation. Nuclear staining of maspin is seen in both BCC and SCC with a suggested tumour suppressor role in BCC.

An emerging role for the nuclear localization of maspin in the suppression of tumor progression and metastasis

Maspin, a member of the serpin family of serine protease inhibitors, was originally identified as a tumor suppressor that is expressed in normal mammary epithelial cells but is reduced or absent in breast carcinomas. Early enthusiasm for maspin as a biomarker for disease progression has been tempered by clinical data that associates maspin with favourable outcomes in some studies and poor prognosis in others. Here, we review all of the published clinical studies for maspin in breast and ovarian cancers and propose that the apparent discordance between clinical reports is a consequence of differential cellular distribution of maspin. Indeed, it was thought that an extracellular pool of maspin possessed tumor suppressor activity, acting by inhibiting migration and increasing cell adhesion. Recent evidence from our group and others indicates, however, that the nuclear localization of maspin in cancer cells is necessary for its tumor suppressor activity. We provide additional data here to demonstrate that nuclear-localized maspin binds to chromatin and is required to effectively prevent cells from metastasizing. Our knowledge of other serpins that localize to the nucleus should help to inform future studies of nuclear maspin. Elucidation of the molecular mechanisms regulating the localization and activities of maspin should pave the way for the development of improved diagnostics and therapies for cancer.

Maspin reprograms the gene expression profile of prostate carcinoma cells for differentiation

Maspin is an epithelial-specific tumor suppressor gene. Previous data suggest that maspin expression may redirect poorly differentiated tumor cells to better differentiated phenotypes. Further, maspin is the first and only endogenous polypeptide inhibitor of histone deacetylase 1 (HDAC1) identified thus far. In the current study, to address what central program of tumor cell redifferentiation is regulated by maspin and how tumor microenvironments further define the effects of maspin, we conducted a systematic and extensive comparison of prostate tumor cells grown in 2-dimensional culture, in 3-dimensional collagen I culture, and as in vivo bone tumors. We showed that maspin was sufficient to drive prostate tumor cells through a spectrum of temporally and spatially polarized cellular processes of redifferentiation, a reversal of epithelial-to-mesenchymal transition (EMT). Genes commonly regulated by maspin were a small subset of HDAC target genes that are closely associated with epithelial differentiation and TGFβ signaling. These results suggest that a specific endogenous HDAC inhibitor may regulate one functionally related subset of HDAC target genes, although additional maspin-induced changes of gene expression may result from tumor interaction with its specific microenvironments. Currently, EMT is recognized as a critical step in tumor progression. To this end, our current study uncovered a link between maspin and a specific mechanism of prostate epithelial differentiation that can reverse EMT.