Serine protease inhibitor Kazal type 1 promotes proliferation of pancreatic cancer cells through the epidermal growth factor receptor

SPINK9 stimulates metalloprotease/EGFR-dependent keratinocyte migration via purinergic receptor activation

Serine protease inhibitors of the Kazal-type 9 (SPINK9) is a keratinocyte-derived cationic peptide that is found most abundantly in the upper layers of the palmar-plantar epidermis. In vitro, the peptide displays the capacity to inhibit specifically kallikrein-related peptidase 5 (KLK5). Here, we report that cells expressing SPINK9 secrete the peptide constitutively. Recombinant SPINK9 (rSPINK9) provoked transactivation of the EGFR in human keratinocytes, resulting in efficient downstream triggering of cell migration. Transactivation occurred via functional upregulation of a disintegrin and metalloproteases (ADAMs), as evidenced by suppression with a metalloproteinase inhibitor and an EGFR-blocking antibody. SPINK9 preparations isolated from human skin also displayed EGFR-transactivating capacity. The classical purinergic receptor antagonists oxidized ATP and pyridoxalphosphate-6-azophenyl-2',4',-disulfonic acid effectively suppressed EGFR transactivation by rSPINK9, indicating that in analogy to what has recently been reported for the cationic antimicrobial peptides cathelicidin LL-37 and bee venom melittin, purinergic receptors have an essential bridging role in promoting the upregulation of ADAM function by the cationic peptide. SPINK9 could represent an example of how a cationic peptide may subserve multiple and interrelated functions that contribute to the maintenance of the physical and immunological barrier of the skin.

Risk factors for pancreatic cancer: underlying mechanisms and potential targets

PURPOSE OF THE REVIEW

Pancreatic cancer is extremely aggressive, forming highly chemo-resistant tumors, and has one of the worst prognoses. The evolution of this cancer is multi-factorial. Repeated acute pancreatic injury and inflammation are important contributing factors in the development of pancreatic cancer. This article attempts to understand the common pathways linking pancreatitis to pancreatic cancer.

RECENT FINDINGS

Intracellular activation of both pancreatic enzymes and the transcription factor NF-κB are important mechanisms that induce acute pancreatitis (AP). Recurrent pancreatic injury due to genetic susceptibility, environmental factors such as smoking, alcohol intake, and conditions such as obesity lead to increases in oxidative stress, impaired autophagy and constitutive activation of inflammatory pathways. These processes can stimulate pancreatic stellate cells, thereby increasing fibrosis and encouraging chronic disease development. Activation of oncogenic Kras mutations through inflammation, coupled with altered levels of tumor suppressor proteins (p53 and p16) can ultimately lead to development of pancreatic cancer.

SUMMARY

Although our understanding of pancreatitis and pancreatic cancer has tremendously increased over many years, much remains to be elucidated in terms of common pathways linking these conditions.

Biomarkers for pancreatic cancer: promising new markers and options beyond CA 19-9

Pancreatic adenocarcinoma accounts for nearly 90-95% of exocrine malignant tumors of the pancreas. Traditionally, overexpressed proteins/epitopes such as CA 19-9, CA-50, CEA, and many others were being used as pancreatic cancer tumor markers. The main utility of these biomarkers was in the diagnosis of pancreatic cancer as well as to assess response to chemotherapy and to determine prognosis and to predict tumor recurrence. However, these markers had significant limitations such as lack of sensitivity, false-negative results in certain blood groups, as well as false-positive elevation in the presence of obstructive jaundice. To circumvent these limitations, an extraordinary amount of research is being performed to identify an accurate tumor marker or a panel of markers that could aid in the management of the pancreatic cancer. Although this research has identified a large number and different variety of biomarkers, few hold future promise as a preferred marker for pancreatic cancer. This review provides an insight into exciting new areas of pancreatic biomarker research such as salivary, pancreatic juice, and stool markers that can be used as a noninvasive test to identify pancreatic cancer. This manuscript also provides a discussion on newer biomarkers, the role of microRNAs, and pancreatic cancer proteomics, which have the potential to identify a preferred tumor marker for pancreatic adenocarcinoma. This review further elaborates on important genetic changes associated with the development and progression of pancreatic cancer that holds the key for the identification of a sensitive biomarker and which could also serve as a therapeutic target.

A novel discriminant score based on tumor-associated trypsin inhibitor for accurate diagnosis of metastasis in patients with breast cancer

Invasion and metastasis of solid tumors require proteolytic enzymes for degradation of the basal membrane and extracellular matrix. Currently, there are no reliable methodologies to predict the risk for metastatic disease. In this context, our aim has been focused on the development of a noninvasive score based on tumor-associated trypsin inhibitor (TATI) for the assessment of metastasis in patients with breast cancer. TATI, trypsin, and soluble epidermal growth factor receptor (sEGFR) were assayed by enzyme-linked immunosorbent assay. CA 15.3 serum level was assayed by microparticle enzyme immunoassay in 265 patients with breast cancer. Statistical analyses were performed by logistic regression and receiver operating characteristic analysis curves. Using multivariate discriminant analysis, a score is selected based on absolute values of the four biochemical markers: TATI-metastatic breast cancer score (TATI-MBCS) = [0.03 × CA 15.3 (U/L) + 0.039 × TATI (ng/ml) + 0.04 × trypsin (ng/ml) + 0.023 × sEGFR (ng/ml) - 6.49 (numerical constant)]. This function correctly classified 84% of metastatic breast cancer at cutoff value = 0.62 (i.e., greater than 0.62 indicates patients with metastatic breast cancer and less than 0.62 indicates patients with nonmetastatic breast cancer). In conclusion, TATI-MBCS is a novel, noninvasive, and simple score which can be applied to discriminate patients with metastatic breast cancer.

Concomitant tumor expression of EGFR and TATI/SPINK1 associates with better prognosis in colorectal cancer

Background

Epidermal growth factor receptor (EGFR) activation plays a role in colorectal cancer (CRC) carcinogenesis, and anti-EGFR drugs are used in treatment of advanced CRC. One of the EGFR ligands is tumor-associated trypsinogen inhibitor TATI, also called serine protease inhibitor Kazal type1 (SPINK 1), which we recently showed to be an independent prognostic marker in CRC.

Methods

We studied the prognostic value of immunohistochemical expression of EGFR and concomitant expression of EGFR and TATI/SPINK1 in a series of 619 colorectal cancer patients.

Results

Of the samples, 92% were positive for EGFR. EGFR+/TATI+ was seen in 62.8%, EGFR+/TATI− in 29.5%, EGFR−/TATI+ in 4.9%, and EGFR−/TATI− in 2.7% of patients. EGFR expression correlated with WHO grade (p = 0.040). In univariate analysis, EGFR expression correlated with favourable survival (p = 0.006). EGFR+/TATI+ patients showed better survival than did those with other combinations (p<0.001). In multivariate analysis, EGFR+/TATI+ was an independent prognostic factor of favourable prognosis (p<0.001).

Conclusion

Concomitant positivity of EGFR and TATI/SPINK1 predicts favourable prognosis in CRC.

Molecular diagnosis of prostate cancer: are we up to age?

Prostate cancer (PCa), a highly heterogeneous disease, is the one of the leading cause of morbidity and mortality in the developed countries. Historically used biomarkers such as prostatic acid phosphatase (PAP), serum prostate-specific antigen (PSA), and its precursor have not stood the challenge of sensitivity and specificity. At present, there is need to re-evaluate the approach to diagnose and monitor PCa. To this end, molecular markers that can accurately identify men with PCa at an early stage, and those who would benefit from early therapeutic intervention, are the need of the hour. There has been unprecedented progress in the development of new PCa biomarkers through advancements in proteomics, tissue DNA and protein/RNA microarray, identification of microRNA, isolation of circulating tumor cells, and tumor immunohistochemistry. This review will examine the current status of prostate cancer biomarkers with emphasis on emerging biomarkers by evaluating their diagnostic and prognostic potentials.

Phylogenetic distribution of protease inhibitors of the Kazal-family within the Arthropoda

In mammalian pancreatic cells, the pancreatic secretory trypsin inhibitor (PSTI) belonging to the Kazal-family prevents the premature activation of digestive enzymes and thus plays an important role in a protective mechanism against tissue destruction by autophagy. Although a similar protective mechanism exists in Arthropoda, the distribution of these inhibitors in this phylum remains obscure. A comprehensive in silico search of nucleotide databases, revealed the presence of members of the Kazal-family in the four major subphyla of the Arthropoda. Especially in the Hexapoda and the Crustacea these inhibitors are widespread, while in the Chelicerata and Myriapoda only a few Kazal-like protease inhibitors were found. A sequence alignment of inhibitors retrieved in the digestive system of insects revealed a conservation of the PSTI characteristics and strong resemblance to vertebrate PSTI. A phylogenetic analysis of these inhibitors showed that they generally cluster according to their order. The results of this data mining study provide new evidence for the existence of an ancient protective mechanism in metazoan digestive systems. Kazal-like inhibitors, which play an important protective role in the pancreas of vertebrates, also seem to be present in Arthropoda.

Do genetic variants in the SPINK1 gene affect the level of serum PSTI?

BACKGROUND

The serine protease inhibitor Kazal type 1 (SPINK1), also known as pancreatic secretory trypsin inhibitor (PSTI), is a peptide secreted by pancreatic acinar cells. Genetic studies have shown an association between SPINK1 gene variants and chronic pancreatitis or recurrent acute pancreatitis. The aim of this study was to clarify whether the SPINK1 variants affect the level of serum PSTI.

METHODS

One hundred sixty-three patients with chronic pancreatitis or recurrent acute pancreatitis and 73 healthy controls were recruited. Serum PSTI concentrations were determined with a commercial radioimmunoassay kit.

RESULTS

Ten patients with the p.N34S variant, 7 with the IVS3+2T>C variant, two with both the p.N34S and the IVS3+2T>C variants, and one with the novel missense p.P45S variant in the SPINK1 gene were identified. The serum PSTI level in patients with no SPINK1 variants was 14.3 ± 9.6 ng/ml (mean ± SD), and that in healthy controls was 10.7 ± 2.2 ng/ml. The PSTI level in patients carrying the IVS3+2T>C variant (5.1 ± 3.4 ng/ml), but not in those with the p.N34S variant (8.9 ± 3.5 ng/ml), was significantly lower than that in the patients without the SPINK1 variants and the healthy controls. The serum PSTI level in the patient with the p.P45S variant was 4.9 ng/ml. Low levels of serum PSTI (<6.0 ng/ml) showed sensitivity of 80 %, specificity of 97 %, and accuracy of 96 % in the differentiation of IVS3+2T>C and p.P45S carriers from non-carriers.

CONCLUSION

Serum PSTI levels were decreased in patients with the IVS3+2T>C and p.P45S variants of the SPINK1 gene.

Role of Intrapancreatic SPINK1/Spink3 Expression in the Development of Pancreatitis

Studies on hereditary pancreatitis have provided evidence in favor of central role for trypsin activity in the disease. Identification of genetic variants of trypsinogen linked the protease to the onset of pancreatitis, and biochemical characterization proposed an enzymatic gain of function as the initiating mechanism. Mutations of serine protease inhibitor Kazal type 1 gene (SPINK1) are shown to be associated with hereditary pancreatitis. We previously reported that Spink3 (a mouse homolog gene of human SPINK1) deficient mice showed excessive autophagy, followed by inappropriate trypsinogen activation in the exocrine pancreas. These data indicate that the role of SPINK1/Spink3 is not only trypsin inhibitor, but also negative regulator of autophagy. On the other hand, recent studies showed that high levels of SPINK1 protein detected in a serum or urine were associated with adverse outcome in various cancer types. It has been suggested that expression of SPINK1 and trypsin is balanced in normal tissue, but this balance could be disrupted during tumor progression. Based on the structural similarity between SPINK1 and epidermal growth factor (EGF), we showed that SPINK1 protein binds and activates EGF receptor, thus acting as a growth factor on tumor cell lines. In this review, we summarize the old and new roles of SPINK1/Spink3 in trypsin inhibition, autophagy, and cancer cell growth. These new functions of SPINK1/Spink3 may be related to the development of chronic pancreatitis.

Tumour-associated trypsin inhibitor TATI is a prognostic marker in colorectal cancer

BACKGROUND

The tumour-associated trypsin inhibitor TATI is expressed together with trypsin in many cancer forms, and an elevated serum level associates with poor prognosis. TATI can reduce tissue destruction by inhibiting trypsin and other proteinases, and in some cancer forms, its high tissue expression is associated with favourable prognosis. We analyzed the prognostic values of TATI, trypsinogen-1 and trypsinogen-2 immunoexpression from tissue array blocks constructed from surgical specimens of 592 colorectal cancer patients.

RESULTS

TATI positivity correlated negatively with differentiation (p < 0.001) and positively with the histological type of adenocarcinoma (p < 0.001). Trypsinogen-1 and trypsinogen-2 positivity correlated with Dukes' stage (p = 0.045, p = 0.050); the percentage of trypsinogen-1- and trypsinogen-2-positive tumours was lower in metastasized (Dukes' stage C-D) than in local (Dukes' stage A-B) disease. In addition, trypsinogen-2 correlated inversely with differentiation (p = 0.012). In univariate analysis, the expression of TATI associated with more favourable cancer-specific survival (p = 0.010). In multivariate analysis, low TATI (p = 0.044), age (p < 0.001), Dukes' stage (p < 0.001), tumour differentiation (p = 0.020) and location in the rectum (p = 0.006) were independent prognostic factors for adverse outcome. Furthermore, TATI expression was an independent prognostic factor in a subgroup of trypsinogen-1- (p = 0.007) and trypsinogen-2-positive (p = 0.006) tumours.

CONCLUSION

TATI tissue expression is an independent prognostic marker in colorectal cancer.

Glycomic and proteomic profiling of pancreatic cyst fluids identifies hyperfucosylated lactosamines on the N-linked glycans of overexpressed glycoproteins

Pancreatic cancer is now the fourth leading cause of cancer deaths in the United States, and it is associated with an alarmingly low 5-year survival rate of 5%. However, a patient's prognosis is considerably improved when the malignant lesions are identified at an early stage of the disease and removed by surgical resection. Unfortunately, the absence of a practical screening strategy and clinical diagnostic test for identifying premalignant lesions within the pancreas often prevents early detection of pancreatic cancer. To aid in the development of a molecular screening system for early detection of the disease, we have performed glycomic and glycoproteomic profiling experiments on 21 pancreatic cyst fluid samples, including fluids from mucinous cystic neoplasms and intraductal papillary mucinous neoplasms, two types of mucinous cysts that are considered high risk to undergo malignant transformation. A total of 80 asparagine-linked (N-linked) glycans, including high mannose and complex structures, were identified. Of special interest was a series of complex N-linked glycans containing two to six fucose residues, located predominantly as substituents on β-lactosamine extensions. Following the observation of these "hyperfucosylated" glycans, bottom-up proteomics experiments utilizing a label-free quantitative approach were applied to the investigation of two sets of tryptically digested proteins derived from the cyst fluids: 1) all soluble proteins in the raw samples and 2) a subproteome of the soluble cyst fluid proteins that were selectively enriched for fucosylation through the use of surface-immobilized Aleuria aurantia lectin. A comparative analysis of these two proteomic data sets identified glycoproteins that were significantly enriched by lectin affinity. Several candidate glycoproteins that appear hyperfucosylated were identified, including triacylglycerol lipase and pancreatic α-amylase, which were 20- and 22-fold more abundant, respectively, following A. aurantia lectin enrichment.

Progress of molecular targeted therapies for prostate cancers

Prostate cancer remains the most commonly diagnosed malignancy and the second leading cause of cancer-related deaths in men in the United States. The current standard of care consists of prostatectomy and radiation therapy, which may often be supplemented with hormonal therapies. Recurrence is common, and many develop metastatic prostate cancer for which chemotherapy is only moderately effective. It is clear that novel therapies are needed for the treatment of the malignant forms of prostate cancer that recur after initial therapies, such as hormone refractory (HRPC) or castration resistant prostate cancer (CRPC). With advances in understanding of the molecular mechanisms of cancer, we have witnessed unprecedented progress in developing new forms of targeted therapy. Several targeted therapeutic agents have been developed and clinically used for the treatment of solid tumors such as breast cancer, non-small cell lung cancer, and renal cancer. Some of these reagents modulate growth factors and/or their receptors, which are abundant in cancer cells. Other reagents target the downstream signal transduction, survival pathways, and angiogenesis pathways that are abnormally activated in transformed cells or metastatic tumors. We will review current developments in this field, focusing specifically on treatments that can be applied to prostate cancers. Finally we will describe aspects of the future direction of the field with respect to discovering biomarkers to aid in identifying responsive prostate cancer patients.

Proteomics portrait of archival lesions of chronic pancreatitis

Chronic pancreatitis is a chronic inflammatory disorder of the pancreas. The etiology is multi-fold, but all lead to progressive scarring and loss of pancreatic function. Early diagnosis is difficult; and the understanding of the molecular events that underlie this progressive disease is limited. In this study, we investigated differential proteins associated with mild and severe chronic pancreatitis in comparison with normal pancreas and pancreatic cancer. Paraffin-embedded formalin-fixed tissues from five well-characterized specimens each of normal pancreas (NL), mild chronic pancreatitis (MCP), severe chronic pancreatitis (SCP) and pancreatic ductal adenocarcinoma (PDAC) were subjected to proteomic analysis using a “label-free” comparative approach. Our results show that the numbers of differential proteins increase substantially with the disease severity, from mild to severe chronic pancreatitis, while the number of dysregulated proteins is highest in pancreatic adenocarcinoma. Important functional groups and biological processes associated with chronic pancreatitis and cancer include acinar cell secretory proteins, pancreatic fibrosis/stellate cell activation, glycoproteins, and inflammatory proteins. Three differential proteins were selected for verification by immunohistochemistry, including collagen 14A1, lumican and versican. Further canonical pathway analysis revealed that acute phase response signal, prothrombin activation pathway, and pancreatic fibrosis/pancreatic stellate cell activation pathway were the most significant pathways involved in chronic pancreatitis, while pathways relating to metabolism were the most significant pathways in pancreatic adenocarcinoma. Our study reveals a group of differentially expressed proteins and the related pathways that may shed light on the pathogenesis of chronic pancreatitis and the common molecular events associated with chronic pancreatitis and pancreatic adenocarcinoma.

Genetic and epigenetic alterations in pancreatic carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. Despite significant progresses in the last decades, the origin of this cancer remains unclear and no efficient therapy exists. PDAC does not arise de novo: three remarkable different types of pancreatic lesions can evolve towards pancreatic cancer. These precursor lesions include: Pancreatic intraepithelial neoplasia (PanIN) that are microscopic lesions of the pancreas, Intraductal Papillary Mucinous Neoplasms (IPMN) and Mucinous Cystic Neoplasms (MCN) that are both macroscopic lesions. However, the cellular origin of these lesions is still a matter of debate.

Classically, neoplasm initiation or progression is driven by several genetic and epigenetic alterations. The aim of this review is to assemble the current information on genetic mutations and epigenetic disorders that affect genes during pancreatic carcinogenesis. We will further discuss the interest of the genetic and epigenetic alterations for the diagnosis and prognosis of PDAC. Large genetic alterations (chromosomal deletion/amplification) and single point mutations are well described for carcinogenesis inducers. Mutations classically occur within key regions of the genome. Consequences are various and include activation of mitogenic pathways or silencing of apoptotic processes. Alterations of K-RAS, P16 and DPC4 genes are frequently observed in PDAC samples and have been described to arise gradually during carcinogenesis. DNA methylation is an epigenetic process involved in imprinting and X chromosome inactivation. Alteration of DNA methylation patterns leads to deregulation of gene expression, in the absence of mutation. Both genetic and epigenetic events influence genes and non-coding RNA expression, with dramatic effects on proliferation, survival and invasion. Besides improvement in our fundamental understanding of PDAC development, highlighting the molecular alterations that occur in pancreatic carcinogenesis could provide new clinical tools for early diagnosis of PDAC and the molecular basis for the development of new effective therapies.

Microarray and proteomic analysis of breast cancer cell and osteoblast co-cultures: role of osteoblast matrix metalloproteinase (MMP)-13 in bone metastasis

Dynamic reciprocal interactions between a tumor and its microenvironment impact both the establishment and progression of metastases. These interactions are mediated, in part, through proteolytic sculpting of the microenvironment, particularly by the matrix metalloproteinases, with both tumors and stroma contributing to the proteolytic milieu. Because bone is one of the predominant sites of breast cancer metastases, we used a co-culture system in which a subpopulation of the highly invasive human breast cancer cell line MDA-MB-231, with increased propensity to metastasize to bone, was overlaid onto a monolayer of differentiated osteoblast MC3T3-E1 cells in a mineralized osteoid matrix. CLIP-CHIP® microarrays identified changes in the complete protease and inhibitor expression profile of the breast cancer and osteoblast cells that were induced upon co-culture. A large increase in osteoblast-derived MMP-13 mRNA and protein was observed. Affymetrix analysis and validation showed induction of MMP-13 was initiated by soluble factors produced by the breast tumor cells, including oncostatin M and the acute response apolipoprotein SAA3. Significant changes in the osteoblast secretomes upon addition of MMP-13 were identified by degradomics from which six novel MMP-13 substrates with the potential to functionally impact breast cancer metastasis to bone were identified and validated. These included inactivation of the chemokines CCL2 and CCL7, activation of platelet-derived growth factor-C, and cleavage of SAA3, osteoprotegerin, CutA, and antithrombin III. Hence, the influence of breast cancer metastases on the bone microenvironment that is executed via the induction of osteoblast MMP-13 with the potential to enhance metastases growth by generating a microenvironmental amplifying feedback loop is revealed.

Therapeutic targeting of SPINK1-positive prostate cancer

Gene fusions involving ETS (erythroblastosis virus E26 transformation-specific) family transcription factors are found in ~50% of prostate cancers and as such can be used as a basis for the molecular subclassification of prostate cancer. Previously, we showed that marked overexpression of SPINK1 (serine peptidase inhibitor, Kazal type 1), which encodes a secreted serine protease inhibitor, defines an aggressive molecular subtype of ETS fusion-negative prostate cancers (SPINK1+/ETS⁻, ~10% of all prostate cancers). Here, we examined the potential of SPINK1 as an extracellular therapeutic target in prostate cancer. Recombinant SPINK1 protein (rSPINK1) stimulated cell proliferation in benign RWPE as well as cancerous prostate cells. Indeed, RWPE cells treated with either rSPINK1 or conditioned medium from 22RV1 prostate cancer cells (SPINK1+/ETS⁻) significantly increased cell invasion and intravasation when compared with untreated cells. In contrast, knockdown of SPINK1 in 22RV1 cells inhibited cell proliferation, cell invasion, and tumor growth in xenograft assays. 22RV1 cell proliferation, invasion, and intravasation were attenuated by a monoclonal antibody (mAb) to SPINK1 as well. We also demonstrated that SPINK1 partially mediated its neoplastic effects through interaction with the epidermal growth factor receptor (EGFR). Administration of antibodies to SPINK1 or EGFR (cetuximab) in mice bearing 22RV1 xenografts attenuated tumor growth by more than 60 and 40%, respectively, or ~75% when combined, without affecting PC3 xenograft (SPINK1⁻/ETS⁻) growth. Thus, this study suggests that SPINK1 may be a therapeutic target in a subset of patients with SPINK1+/ETS⁻ prostate cancer. Our results provide a rationale for both the development of humanized mAbs to SPINK1 and evaluation of EGFR inhibition in SPINK1+/ETS⁻ prostate cancers.

A two-step toward personalized therapies for prostate cancer

Identifying the dominant genetic alterations that drive tumorigenesis is essential for developing targeted cancer therapies. Recent work has demonstrated that prostate tumors can be stratified by dominant genetic alterations, such as chromosomal rearrangements involving ETS (Erythroblastosis virus E26 transformation-specific) family transcription factors or overexpression of SPINK1, a gene that encodes a secreted serine protease inhibitor. In this issue of Science Translational Medicine, Ateeq et al. provide evidence to support a rationale for targeting the SPINK1 protein in the SPINK1+/ETS⁻ subset of prostate tumors and also describe a potential interaction of SPINK1 with epidermal growth factor receptor that could be an additional target for therapeutic intervention.

Combined genomic and phenotype screening reveals secretory factor SPINK1 as an invasion and survival factor associated with patient prognosis in breast cancer

Secretory factors that drive cancer progression are attractive immunotherapeutic targets. We used a whole-genome data-mining approach on multiple cohorts of breast tumours annotated for clinical outcomes to discover such factors. We identified Serine protease inhibitor Kazal-type 1 (SPINK1) to be associated with poor survival in estrogen receptor-positive (ER+) cases. Immunohistochemistry showed that SPINK1 was absent in normal breast, present in early and advanced tumours, and its expression correlated with poor survival in ER+ tumours. In ER− cases, the prognostic effect did not reach statistical significance. Forced expression and/or exposure to recombinant SPINK1 induced invasiveness without affecting cell proliferation. However, down-regulation of SPINK1 resulted in cell death. Further, SPINK1 overexpressing cells were resistant to drug-induced apoptosis due to reduced caspase-3 levels and high expression of Bcl2 and phospho-Bcl2 proteins. Intriguingly, these anti-apoptotic effects of SPINK1 were abrogated by mutations of its protease inhibition domain. Thus, SPINK1 affects multiple aggressive properties in breast cancer: survival, invasiveness and chemoresistance. Because SPINK1 effects are abrogated by neutralizing antibodies, we suggest that SPINK1 is a viable potential therapeutic target in breast cancer.

Protein alterations associated with pancreatic cancer and chronic pancreatitis found in human plasma using global quantitative proteomics profiling

Pancreatic cancer is a lethal disease that is difficult to diagnose at early stages when curable treatments are effective. Biomarkers that can improve current pancreatic cancer detection would have great value in improving patient management and survival rate. A large scale quantitative proteomics study was performed to search for the plasma protein alterations associated with pancreatic cancer. The enormous complexity of the plasma proteome and the vast dynamic range of protein concentration therein present major challenges for quantitative global profiling of plasma. To address these challenges, multidimensional fractionation at both protein and peptide levels was applied to enhance the depth of proteomics analysis. Employing stringent criteria, more than 1300 proteins total were identified in plasma across 8-orders of magnitude in protein concentration. Differential proteins associated with pancreatic cancer were identified, and their relationship with the proteome of pancreatic tissue and pancreatic juice from our previous studies was discussed. A subgroup of differentially expressed proteins was selected for biomarker testing using an independent cohort of plasma and serum samples from well-diagnosed patients with pancreatic cancer, chronic pancreatitis, and nonpancreatic disease controls. Using ELISA methodology, the performance of each of these protein candidates was benchmarked against CA19-9, the current gold standard for a pancreatic cancer blood test. A composite marker of TIMP1 and ICAM1 demonstrate significantly better performance than CA19-9 in distinguishing pancreatic cancer from the nonpancreatic disease controls and chronic pancreatitis controls. In addition, protein AZGP1 was identified as a biomarker candidate for chronic pancreatitis. The discovery and technical challenges associated with plasma-based quantitative proteomics are discussed and may benefit the development of plasma proteomics technology in general. The protein candidates identified in this study provide a biomarker candidate pool for future investigations.

Mechanisms of prostate cancer initiation and progression

Prostate cancer is a major health problem as it continues to be the most frequently diagnosed cancer in men in the Western world. While improved early detection significantly decreased mortality, prostate cancer still remains the second leading cause of cancer-related death in Western men. Understanding the mechanisms of prostate cancer initiation and progression should have a significant impact on development of novel therapeutic approaches that can help to combat this disease. The recent explosion of novel high-throughput genetic technologies together with studies in animal models and human tissues allowed a comprehensive analysis and functional validation of the molecular changes. This chapter will summarize and discuss recently identified critical genetic and epigenetic changes that drive prostate cancer initiation and progression. These discoveries should help concentrate the efforts of drug development on key pathways and molecules, and finally translate the knowledge that is gained from mechanistic studies into effective treatments.

Galectin-3 regulates MUC1 and EGFR cellular distribution and EGFR downstream pathways in pancreatic cancer cells

MUC1 is a transmembrane glycoprotein which is typically expressed at the apical membrane of normal epithelial cells. In cancer cells, the over-expression of MUC1 and its aberrant localization around the cell membrane and in the cytoplasm favours its interaction with different protein partners such as epidermal growth factor receptor (EGFR) and can promote tumour proliferation through the activation of oncogenic signalling pathways. Our aims were to study the mechanisms inducing MUC1 cytoplasmic localization in pancreatic cancer cells, and to decipher their impact on EGFR cellular localization and activation. Our results showed that galectin-3, an endogenous lectin, is co-expressed with MUC1 in human pancreatic ductal adenocarcinoma, and that it favours the endocytosis of MUC1 and EGFR. Depletion of galectin-3 by RNA interference increased the interaction between MUC1 and EGFR, EGFR and ERK-1,2 phosphorylation, and translocation of EGFR to the nucleus. On the contrary, silencing of galectin-3 led to a decrease of cyclin-D1 levels and of cell proliferation. The galectin-3-dependent regulation of MUC1/EGFR functions may represent an interesting mechanism modulating the EGFR-stimulated cell growth of pancreatic cancer cells.

Increased serum levels of tumour-associated trypsin inhibitor independently predict a poor prognosis in colorectal cancer patients

Background

There is an insufficient number of reliable prognostic and response predictive biomarkers in colorectal cancer (CRC) management. In a previous study, we found that high tumour tissue expression of tumour-associated trypsin inhibitor (TATI) correlated with liver metastasis and an impaired prognosis in CRC. The aim of this study was to investigate the prognostic validity of serum TATI (s-TATI) in CRC. We further assessed the prognostic value of carcino-embryonic antigen in serum (s-CEA) and the interrelationship between s-TATI and TATI in tissue (t-TATI).

Methods

Using an immunofluorometric assay, s-TATI levels were analysed in 334 preoperatively collected serum samples from patients with CRC. Spearman's Rho and Chi-square test were used for analysis of correlations between s-TATI and clinicopathological parameters, s-CEA and t-TATI. Kaplan-Meier analysis and Cox uni- and multivariate regression analysis were used to estimate disease free survival (DFS) and overall survival (OS) according to quartiles of s-TATI and cut-offs derived from ROC-analysis of s-TATI and s-CEA.

Results

Increased levels of s-TATI were associated with a reduced DFS (HR = 2.00; 95% CI 1.40-2.84, P < 0.001) and OS (HR = 2.40; 95% CI 1.74-3.33, P < 0.001). (HR = 2.89; 95% CI 1.96-4.25). This association remained significant in multivariate analysis. The association for OS remained significant in multivariate analysis (HR = 1.51; 95% CI 1.03-2.22, P = 0.034 for DFS and HR = 1.78; 95% CI 1.25-2.53, P = 0.001 for OS). There was no significant association between s-TATI and t-TATI. The prognostic value of s-CEA was also evident, but somewhat weaker than for s-TATI.

Conclusions

High preoperative s-TATI levels predict a poor prognosis in patients with CRC, and the prognostic value is independent of established prognostic parameters and t-TATI expression. These data suggest that s-TATI might be a useful marker for prognostic stratification in CRC.

Role of secretory protease inhibitor SPINK3 in mouse uterus during early pregnancy

Successful embryo implantation depends on intricate epithelial-stromal cross-talk. However, molecular modulators involved in this cellular communication remain poorly elucidated. Using multiple approaches, we have investigated the spatiotemporal expression and regulation of serine protease inhibitor Kazal type 3 (SPINK3) in mouse uterus during the estrous cycle and early pregnancy. In cycling mice, both SPINK3 mRNA and protein are only expressed during proestrus. In the pregnant mouse, the expression levels of both SPINK3 mRNA and protein increase on days 5-8 and then decline. Spink3 mRNA is expressed exclusively in the uterine glandular epithelium, whereas SPINK3 protein is localized on the surface of both luminal and glandular epithelium and in the decidua. Moreover, SPINK3 in the decidua has been observed in the primary decidual zone on day 6 and the secondary decidual zone on days 7-8; this is tightly associated with the progression of decidualization. SPINK3 has also been found in decidual cells of the artificially decidualized uterine horn but not control horn, whereas Spink3 mRNA localizes in the glands of both horns. The expression of endometrial Spink3 is not regulated by the blastocyst according to its expression pattern during pseudopregnancy and delayed implantation but is induced by progesterone and further augmented by a combination of progesterone and estrogen in ovariectomized mice. Thus, uterine-gland-derived SPINK3, as a new paracrine modulator, might play an important role in embryo implantation through its influence on stromal decidualization in mice.

Pancreatic secretory trypsin inhibitor: More than a trypsin inhibitor

Kazal-type serine protease inhibitor is one of the most important and widely distributed protease inhibitor families. Pancreatic secretory trypsin inhibitor (PSTI), also known as serine protease inhibitor Kazal type I(SPINK1), binds rapidly to trypsin, inhibits its activity and is likely to protect the pancreas from prematurely activated trypsinogen. Therefore, it is an important factor in the onset of pancreatitis. Recent studies found that PSTI/SPINK1 is also involved in self-regulation of acinar cell phagocytosis, proliferation and growth of a variety of cell lines. In addition, it takes part in the response to inflammatory factor or injury and is highly related to adult type II citrullinemia.

Association of SPINK1 expression and TMPRSS2:ERG fusion with prognosis in endocrine-treated prostate cancer

PURPOSE

The aim of the study was to examine whether TMPRSS2:ERG fusion or SPINK1 protein expression is associated with hormone responsiveness of prostate cancer and can thus be used as a biomarker.

EXPERIMENTAL DESIGN

Diagnostic needle biopsies from prostate cancer patients primarily treated by endocrine therapy were evaluated for TMPRSS2:ERG fusion with fluorescence in situ hybridization and SPINK1 protein expression with immunohistochemistry.

RESULTS

The frequency of TMPRSS2:ERG fusion in 178 biopsies of hormonally treated patients was 34%. Of the fusion-positive cases, 71% showed deletion between the two genes, and 23% showed gain of the fusion. The fusion was associated with high Ki-67 staining (P=0.001), age at diagnosis (P=0.024), and tumor area (P=0.006), but not with Gleason score, T stage, M stage, prostate-specific antigen (PSA), or progression-free survival. Strong positive SPINK1 expression was found in 11% (21 of 186) of the biopsies. SPINK1-positive cases had significantly shorter progression-free survival compared with SPINK1-negative cases (P=0.001). The expression was not associated with any other clinicopathologic variables studied. In a multivariate analysis, SPINK1 expression showed independent prognostic value, with a relative risk of 2.3 (95% confidence interval, 1.1-4.6). SPINK1 expression and the fusion were not associated with each other.

CONCLUSIONS

There was no association between TMPRSS2:ERG fusion and prognosis, suggesting that TMPRSS2:ERG rearrangement does not implicate hormone dependence of the cancer. SPINK1 expression, found in approximately 10% of prostate cancers, was associated with aggressive form of the disease and could serve as a biomarker in endocrine-treated prostate cancer.