Maspin is a deoxycholate-inducible, anti-apoptotic stress-response protein differentially expressed during colon carcinogenesis

Importance of microbial defence systems to bile salts and mechanisms of serum cholesterol reduction

An important feature of the intestinal microbiota, particularly in the case of administered probiotic microorganisms, is their resistance to conditions in the gastrointestinal tract, particularly tolerance to and growth in the presence of bile salts. Bacteria can use several defence mechanisms against bile, including special transport mechanisms, the synthesis of various types of surface proteins and fatty acids or the production of exopolysaccharides. The ability to enzymatically hydrolyse bile salts occurs in a variety of bacteria. Choloylglycine hydrolase (EC 3.5.1.24), a bile salt hydrolase, is a constitutive intracellular enzyme responsible for the hydrolysis of an amide bond between glycine or taurine and the steroid nucleus of bile acids. Its presence was demonstrated in specific microorganisms from several bacterial genera (Lactobacillus spp., Bifidobacterium spp., Clostridium spp., Bacteroides spp.). Occurrence and gene arrangement encoding this enzyme are highly variable in probiotic microorganisms. Bile salt hydrolase activity may provide the possibility to use the released amino acids by bacteria as sources of carbon and nitrogen, to facilitate detoxification of bile or to support the incorporation of cholesterol into the cell wall. Deconjugation of bile salts may be directly related to a lowering of serum cholesterol levels, from which conjugated bile salts are synthesized de novo. Furthermore, the ability of microorganisms to assimilate or to bind ingested cholesterol to the cell wall or to eliminate it by co-precipitation with released cholic acid was also documented. Some intestinal microflora produce cholesterol reductase that catalyses the conversion of cholesterol to insoluble coprostanol, which is subsequently excreted in faeces, thereby also reducing the amount of exogenous cholesterol.

Maspin inhibits macrophage phagocytosis and enhances inflammatory cytokine production via activation of NF-κB signaling

Maspin (mammary serine protease inhibitor) is a non-inhibitory member of the serine protease inhibitor superfamily and a tumor suppressor in several cancers due to its ability to inhibit cell invasion, angiogenesis, and promote apoptosis. However, its immunomodulatory function remains largely unexplored. Thus, we explored the potential link between Maspin and macrophage function, first evaluating the regulatory effects of conditioned medium (CM) of a Maspin-overexpressing CHO cell strain on mouse peritoneal macrophage phagocytosis and cytokine secretion. Next, we used a transwell co-culture system and recombinant Maspin (rMaspin) to confirm the effects of Maspin on macrophages, and attempted to clarify the underlying mechanisms. We found that irrespective of CM, rMaspin or co-culture of Maspin-overexpressing cells with macrophages impaired macrophages phagocytosing Saccharomyces cerevisiae. Furthermore, q-RT-PCR or ELISA confirmed increased IL-1β, TNF-α, IFN-γ, IL-6, IL-12, IL-10, and M1 marker iNOS production in macrophages after Maspin stimulation, but TGF-β and M2 marker Arg-1 production were suppressed. Western blot showed activated NF-κB signaling in Maspin-stimulated macrophages; upregulated cytokines were lowered, and impaired phagocytosis recovered after blocking NF-κB signaling with PDTC. Thus, Maspin mildly inhibited phagocytic activity, but markedly enhanced inflammatory cytokine production and likely skewed macrophages towards M1 polarization, partially due to activation of NF-κB signaling. These results reveal a novel biological function of Maspin in modulating macrophage activity and may open a new avenue for Maspin-based tumor therapy.

Integrative analysis of the colorectal cancer proteome: potential clinical impact

INTRODUCTION

Colorectal cancer (CRC) is one of the common types of cancer that affects a significant proportion of the population and is a major contributor to cancer related mortality. The relatively poor survival rate of CRC could be improved through the identification of clinically useful biomarkers. Areas covered: This review highlights the need for biomarkers and discusses recent proteomics discoveries in the aspects of CRC clinical practice including diagnosis, prognosis, therapy, screening and molecular pathological epidemiology (MPE). Studies have been evaluated in relation to biomarker target, methodology, sample selection, limitations, and potential impact. Finally, the progress in proteomic approaches is briefly discussed and the main difficulties facing the translation of proteomics biomarkers into the clinical practice are highlighted. Expert commentary: The establishment of specific guidelines, best practice recommendations and the improvement in proteomic strategies will significantly improve the prospects for developing clinically useful biomarkers.

TMEM45A, SERPINB5 and p16INK4A transcript levels are predictive for development of high-grade cervical lesions

Women persistently infected with human papillomavirus (HPV) type 16 are at high risk for development of cervical intraepithelial neoplasia grade 3 or cervical cancer (CIN3+). We aimed to identify biomarkers for progression to CIN3+ in women with persistent HPV16 infection. In this prospective study, 11,088 women aged 20-29 years were enrolled during 1991-1993, and re-invited for a second visit two years later. Cervical cytology samples obtained at both visits were tested for HPV DNA by Hybrid Capture 2 (HC2), and HC2-positive samples were genotyped by INNO-LiPA. The cohort was followed for up to 19 years via a national pathology register. To identify markers for progression to CIN3+, we performed microarray analysis on RNA extracted from cervical swabs of 30 women with persistent HPV16-infection and 11 HPV-negative women. Six genes were selected and validated by quantitative PCR. Three genes were subsequently validated within a different and large group of women from the same cohort. Secondly, Kaplan-Meier and Cox-regression analyses were used to investigate whether expression levels of those three genes predict progression to CIN3+. We found that high transcript levels of TMEM45A, SERPINB5 and p16INK4a at baseline were associated with increased risk of CIN3+ during follow-up. The hazard ratios of CIN3+ per 10-fold increase in baseline expression level were 1.6 (95% CI: 1.1-2.3) for TMEM45A, 1.6 (95% CI: 1.1-2.5) for p16INK4a, and 1.8 (95% CI: 1.2-2.7) for SERPINB5. In conclusion, high mRNA expression levels of TMEM45A, SERPINB5 and p16INK4a were associated with increased risk of CIN3+ in persistently HPV16-infected women.

Nuclear maspin expression as a predictive marker for fluorouracil treatment response in colon cancer

BACKGROUND

Maspin is a member of the serpin family of protease inhibitors whose function in colorectal cancer is not fully understood. The objective of this study was to determine whether level of maspin expression could have prognostic or predictive value in colorectal cancer.

MATERIAL AND METHODS

Maspin expression was assessed using immunohistochemistry on tissue microarrays obtained from 380 patients with stage II and III colorectal cancer randomized to adjuvant chemotherapy with fluorouracil and levamisole (5-FU/Lev) or to surgery only (control), with scores (0-300) based on presence (0-100) and intensity (0-3) of maspin expression. Associations with disease-free survival (DFS), cancer-specific survival (CSS) and prognostic factors were determined.

RESULTS

Maspin expression was predominantly nuclear and present in tumor tissue in 99% of the cases. No associations with clinicopathological factors were identified. In colon cancer patients receiving adjuvant chemotherapy, maspin expression level was significantly associated with CSS [HR 1.43 per 50 points increase in maspin score (p = 0.021)] in multivariate analyses, and a significant interaction between treatment status and maspin expression (p = 0.045) was found. Kaplan-Meier plots from colon cancer patients showed a significant treatment benefit in patients with low maspin expression, but not for individuals with medium/high expression. Level of maspin expression was not significantly related to clinical outcome in rectal cancer or in any of the control groups.

CONCLUSIONS

In patients with colon cancer a low nuclear maspin expression was an independent predictor of benefit from adjuvant chemotherapy with 5-FU/Lev. A prognostic value of maspin expression was not found in this material.

Expression and localization of maspin in cervical cancer and its role in tumor progression and lymphangiogenesis

Objectives

Cervical cancer is the most common malignant tumor in female reproductive tract and primarily metastasizes through the lymphatic system that will affect prognosis of patients. Maspin, a member of the serine protease inhibitors (serpins) super family, has recently been indicated as a tumor suppressor in many cancers. In this study, we investigated the clinical significance of maspin expression, especially the subcellular location of maspin and its functional role in progression and lymphangiogenesis, in cervical squamous cell carcinoma.

Methods

Labelled streptavidin biotin method (LSAB) was used to determine cytoplasmic and nuclear maspin expressions, respectively, in 13 cases of normal cervix, 15 cases of cervical intraepithelial neoplasia grade 3 (CIN3), 62 cases of squamous cell carcinoma (SCC) of the uterine cervix, and 13 cases of pelvic lymphatic nodes which were all positive lymphatic nodes in our selected cancer cases. LSAB is also used to detect podoplanin which is used for counting density of lymphatic microvessels (LMVD). The clinical significance of subcellular maspin expression and the relationship between maspin expression and LMVD in cervical cancer are analyzed.

Results

Both cytoplasmic and nuclear maspin expressions in SCC were significantly weaker than those of normal cervix and CIN3. Nuclear maspin expression showed a peak in CIN3 and then dropped in SCC. Declined maspin expression was correlated with later clinical stage, increased LMVD, and lymphatic metastasis.

Conclusions

Our results suggest that subcellular location of maspin expression is a potential predictive factor in tumor progression and in patients’ prognosis of cervical cancer, and maspin plays a suppression role in lymphangiogenesis and metastasis.

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.

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.

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.

Deficient expression of DNA repair enzymes in early progression to sporadic colon cancer

Background

Cancers often arise within an area of cells (e.g. an epithelial patch) that is predisposed to the development of cancer, i.e. a "field of cancerization" or "field defect." Sporadic colon cancer is characterized by an elevated mutation rate and genomic instability. If a field defect were deficient in DNA repair, DNA damages would tend to escape repair and give rise to carcinogenic mutations.

Purpose

To determine whether reduced expression of DNA repair proteins Pms2, Ercc1 and Xpf (pairing partner of Ercc1) are early steps in progression to colon cancer.

Results

Tissue biopsies were taken during colonoscopies of 77 patients at 4 different risk levels for colon cancer, including 19 patients who had never had colonic neoplasia (who served as controls). In addition, 158 tissue samples were taken from tissues near or within colon cancers removed by resection and 16 tissue samples were taken near tubulovillous adenomas (TVAs) removed by resection. 568 triplicate tissue sections (a total of 1,704 tissue sections) from these tissue samples were evaluated by immunohistochemistry for 4 DNA repair proteins. Substantially reduced protein expression of Pms2, Ercc1 and Xpf occurred in field defects of up to 10 cm longitudinally distant from colon cancers or TVAs and within colon cancers. Expression of another DNA repair protein, Ku86, was infrequently reduced in these areas. When Pms2, Ercc1 or Xpf were reduced in protein expression, then either one or both of the other two proteins most often had reduced protein expression as well. The mean inner colon circumferences, from 32 resections, of the ascending, transverse and descending/sigmoid areas were measured as 6.6 cm, 5.8 cm and 6.3 cm, respectively. When combined with other measurements in the literature, this indicates the approximate mean number of colonic crypts in humans is 10 million.

Conclusions

The substantial deficiencies in protein expression of DNA repair proteins Pms2, Ercc1 and Xpf in about 1 million crypts near cancers and TVAs suggests that the tumors arose in field defects that were deficient in DNA repair and that deficiencies in Pms2, Ercc1 and Xpf are early steps, often occurring together, in progression to colon cancer.