Candidate serum biomarkers for prostate adenocarcinoma identified by mRNA differences in prostate tissue and verified with protein measurements in tissue and blood

TGFβ-activated Asporin interacts with STMN1 to promote prostate cancer docetaxel chemoresistance and metastasis by upregulating the Wnt/β-catenin signaling pathway

AIMS

Prostate cancer (PCa) remains a significant challenge in oncology due to high rates of drug resistance following standard treatment with docetaxel-based chemotherapy. Asporin (ASPN) has been regarded as an oncogene and its upregulation is closely associated with malignant behavior and poor prognosis in multiple cancers. Studies indicated that abnormal activation of the Wnt/β-catenin signaling pathway is prevalent in PCa. This study investigated the important role of ASPN in regulating Wnt/β-catenin signaling pathway in docetaxel resistance and metastasis of PCa.

METHODS

The impacts of ASPN on the docetaxel chemoresistance and metastasis of PCa cells were investigated in vitro and in vivo assays. Lastly, the underlying mechanism of ASPN was revealed by Western blot, protein immunocoprecipitation, Immunofluorescence, Immunohistochemical staining, liquid chromatography-mass spectrometry, and rescue experiments.

RESULTS

In present study, we reported that ASPN is highly expressed in PCa cells and tissues. Functional and molecular analyses showed that ASPN is activated by TGFβ and interacts with STMN1. ASPN increases the expression of β-catenin and promotes its nuclear accumulation by mediating the activation of the Wnt/β-catenin signaling pathway, thereby enhancing the stemness and epithelial-mesenchymal transition (EMT) of PCa cells, ultimately facilitating the docetaxel resistance and metastasis of PCa cells.

CONCLUSIONS

Our findings identify ASPN as a novel upstream regulatory factor of Wnt/β-catenin signaling pathway, suggesting that targeting the ASPN/STMN1/β-catenin axis could be a promising strategy for PCa intervention.

The role of proinflammatory cytokines and CXC chemokines (CXCL1-CXCL16) in the progression of prostate cancer: insights on their therapeutic management

Reproductive cancers are malignancies that develop in the reproductive organs. One of the leading cancers affecting the male reproductive system on a global scale is prostate cancer (PCa). The negative consequences of PCa metastases endure and are severe, significantly affecting mortality and life quality for those who are affected. The association between inflammation and PCa has captured interest for a while. Inflammatory cells, cytokines, CXC chemokines, signaling pathways, and other elements make up the tumor microenvironment (TME), which is characterized by inflammation. Inflammatory cytokines and CXC chemokines are especially crucial for PCa development and prognosis. Cytokines (interleukins) and CXC chemokines such as IL-1, IL-6, IL-7, IL-17, TGF-β, TNF-α, CXCL1-CXCL6, and CXCL8-CXCL16 are thought to be responsible for the pleiotropic effects of PCa, which include inflammation, progression, angiogenesis, leukocyte infiltration in advanced PCa, and therapeutic resistance. The inflammatory cytokine and CXC chemokines systems are also promising candidates for PCa suppression and immunotherapy. Therefore, the purpose of this work is to provide insight on how the spectra of inflammatory cytokines and CXC chemokines evolve as PCa develops and spreads. We also discussed recent developments in our awareness of the diverse molecular signaling pathways of these circulating cytokines and CXC chemokines, as well as their associated receptors, which may one day serve as PCa-targeted therapies. Moreover, the current status and potential of theranostic PCa therapies based on cytokines, CXC chemokines, and CXC receptors (CXCRs) are examined.

The Role of CXCL11 and its Receptors in Cancer: Prospective but Challenging Clinical Targets

Chemokine ligand 11 is a member of the CXC chemokine family and exerts its biological function mainly through binding to CXCR3 and CXCR7. The CXCL11 gene is ubiquitously overexpressed in various human malignant tumors; however, its specific mechanisms vary among different cancer types. Recent studies have found that CXCL11 is involved in the activation of multiple oncogenic signaling pathways and is closely related to tumorigenesis, progression, chemotherapy tolerance, immunotherapy efficacy, and poor prognosis. Depending on the specific expression of its receptor subtype, CXCL11 also has a complex 2-fold role in tumours; therefore, directly targeting the structure-function of CXCL11 and its receptors may be a challenging task. In this review, we summarize the biological functions of CXCL11 and its receptors and their roles in various types of malignant tumors and point out the directions for clinical applications.

ASPORIN: A root of the matter in tumors and their host environment

Asporin (ASPN) has been identified as one of the members of the class I small leucine-rich proteoglycans (SLRPs) family in the extracellular matrix (ECM). It is involved in classic ensigns of cancers such as self-dependent growth, resistance to growth inhibitors, restricting apoptosis, cancer metastasis, and bone-related disorders. ASPN is different from other members of SLRPs, such as decorin (DCN) and biglycan (BGN), in a way that it contains a distinctive length of aspartate (D) residues in the amino (N) -terminal region. These D-repeats residues possess germline polymorphisms and are identified to be linked with cancer progression and osteoarthritis (OA). The polyaspartate stretch in the N-terminal region of the protein and its resemblance to DCN are the reasons it is called asporin. In this review, we comprehensively summarized and updated the dual role of ASPN in various malignancies, its structure in mice and humans, variants, mutations, cancer-associated signalings and functions, the relationship between ASPN and cancer-epithelial, stromal fibroblast crosstalk, immune cells and immunosuppression in cancer and other diseases. In cancer and other bone-related diseases, ASPN is identified to be regulating various signaling pathways such as TGFβ, Wnt/β-catenin, notch, hedgehog, EGFR, HER2, and CD44-mediated Rac1. These pathways promote cancer cell invasion, proliferation, and migration by mediating the epithelial-to-mesenchymal transition (EMT) process. Finally, we discussed mouse models mimicking ASPN in vivo function in cancers and the probability of therapeutic targeting of ASPN in cancer cells, fibrosis, and other bone-related diseases.

The Potential of Extracellular Matrix- and Integrin Adhesion Complex-Related Molecules for Prostate Cancer Biomarker Discovery

Prostate cancer is among the top five cancer types according to incidence and mortality. One of the main obstacles in prostate cancer management is the inability to foresee its course, which ranges from slow growth throughout years that requires minimum or no intervention to highly aggressive disease that spreads quickly and resists treatment. Therefore, it is not surprising that numerous studies have attempted to find biomarkers of prostate cancer occurrence, risk stratification, therapy response, and patient outcome. However, only a few prostate cancer biomarkers are used in clinics, which shows how difficult it is to find a novel biomarker. Cell adhesion to the extracellular matrix (ECM) through integrins is among the essential processes that govern its fate. Upon activation and ligation, integrins form multi-protein intracellular structures called integrin adhesion complexes (IACs). In this review article, the focus is put on the biomarker potential of the ECM- and IAC-related molecules stemming from both body fluids and prostate cancer tissue. The processes that they are involved in, such as tumor stiffening, bone turnover, and communication via exosomes, and their biomarker potential are also reviewed.

A chemical probe for BAG1 targets androgen receptor-positive prostate cancer through oxidative stress signaling pathway

BAG1 is a family of polypeptides with a conserved C-terminal BAG domain that functions as a nucleotide exchange factor for the molecular chaperone HSP70. BAG1 proteins also control several signaling processes including proteostasis, apoptosis, and transcription. The largest isoform, BAG1L, controls the activity of the androgen receptor (AR) and is upregulated in prostate cancer. Here, we show that BAG1L regulates AR dynamics in the nucleus and its ablation attenuates AR target gene expression especially those involved in oxidative stress and metabolism. We show that a small molecule, A4B17, that targets the BAG domain downregulates AR target genes similar to a complete BAG1L knockout and upregulates the expression of oxidative stress-induced genes involved in cell death. Furthermore, A4B17 outperformed the clinically approved antagonist enzalutamide in inhibiting cell proliferation and prostate tumor development in a mouse xenograft model. BAG1 inhibitors therefore offer unique opportunities for antagonizing AR action and prostate cancer growth.

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BAG1L interacts with a sequence overlapping a polyalanine tract in the AR NTD

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Knockdown of BAG1L increase AR dynamics in the nucleus

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BAG1L uses ROS pathway to regulate AR⁺ prostate cancer cell proliferation

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A small molecule BAG1 inhibitor inhibits prostate tumor growth in mouse xenografts

PACE4-altCT isoform of proprotein convertase PACE4 as tissue and plasmatic biomarker for prostate cancer

The proprotein convertase PACE4 has demonstrated value as a viable therapeutic target in prostate cancer (PCa). A novel isoform named PACE4-altCT, which arises in neoplastic lesions, plays an important role in tumor progression and has been validated as a pharmacological target. With the discovery of its overexpression in PCa and the alternative splicing of its pre-RNA to generate an oncogenic C-terminally modified isoform named PACE4-altCT, understanding and validating its value as a potential biomarker is of great interest either from prognostic or targeted therapy intervention. Expression of ERG in LNCaP cells was used to investigate the relationship between ERG expression occurring in PCa cells and PACE4-altCT expression by Western blot and qPCR. Using immunohistochemistry, the expression levels of PACE4 isoforms in patient tissues were investigated and correlated with ERG tumor status and Gleason score. An ELISA method was developed using affinity purified recombinant protein and used for quantitative analysis of plasma concentrations of PACE4-altCT and used for correlation. In contrast with the consensual isoform, PACE4-altCT was only strongly overexpressed in prostate cancer patients, correlated with ERG expression levels. Despite its intracellular retention PACE4-altCT could be detected in the plasma of most patients with prostate cancer, whereas it was only found at low levels in normal patients whereas total plasmatic PACE4 levels did not vary significantly between groups. Our study demonstrates that PACE4-altCT is strongly overexpressed in prostate cancer using both immunohistochemical and ELISA techniques and may have some interesting potential as a biomarker.

Metabolic Phenotyping in Prostate Cancer Using Multi-Omics Approaches

Prostate cancer (PCa), one of the most frequently diagnosed cancers among men worldwide, is characterized by a diverse biological heterogeneity. It is well known that PCa cells rewire their cellular metabolism to meet the higher demands required for survival, proliferation, and invasion. In this context, a deeper understanding of metabolic reprogramming, an emerging hallmark of cancer, could provide novel opportunities for cancer diagnosis, prognosis, and treatment. In this setting, multi-omics data integration approaches, including genomics, epigenomics, transcriptomics, proteomics, lipidomics, and metabolomics, could offer unprecedented opportunities for uncovering the molecular changes underlying metabolic rewiring in complex diseases, such as PCa. Recent studies, focused on the integrated analysis of multi-omics data derived from PCa patients, have in fact revealed new insights into specific metabolic reprogramming events and vulnerabilities that have the potential to better guide therapy and improve outcomes for patients. This review aims to provide an up-to-date summary of multi-omics studies focused on the characterization of the metabolomic phenotype of PCa, as well as an in-depth analysis of the correlation between changes identified in the multi-omics studies and the metabolic profile of PCa tumors.

Reciprocal interplay between asporin and decorin: Implications in gastric cancer prognosis

Effective patient prognosis necessitates identification of novel tumor promoting drivers of gastric cancer (GC) which contribute to worsened conditions by analysing TCGA-gastric adenocarcinoma dataset. Small leucine-rich proteoglycans, asporin (ASPN) and decorin (DCN), play overlapping roles in development and diseases; however, the mechanisms underlying their interplay remain elusive. Here, we investigated the complex interplay of asporin, decorin and their interaction with TGFβ in GC tumor and corresponding normal tissues. The mRNA levels, protein expressions and cellular localizations of ASPN and DCN were analyzed using real-time PCR, western blot and immunohistochemistry, respectively. The protein-protein interaction was predicted by in-silico interaction analysis and validated by co-immunoprecipitation assay. The correlations between ASPN and EMT proteins, VEGF and collagen were achieved using western blot analysis. A significant increase in expression of ASPN in tumor tissue vs. normal tissue was observed in both TCGA and our patient cohort. DCN, an effective inhibitor of the TGFβ pathway, was negatively correlated with stages of GC. Co-immunoprecipitation demonstrated that DCN binds with TGFβ, in normal gastric epithelium, whereas in GC, ASPN preferentially binds TGFβ. Possible activation of the canonical TGFβ pathway by phosphorylation of SMAD2 in tumor tissues suggests its role as an intracellular tumor promoter. Furthermore, tissues expressing ASPN showed unregulated EMT signalling. Our study uncovers ASPN as a GC-promoting gene and DCN as tumor suppressor, suggesting that ASPN can act as a prognostic marker in GC. For the first time, we describe the physical interaction of TGFβ with ASPN in GC and DCN with TGFβ in GC and normal gastric epithelium respectively. This study suggests that prevention of ASPN-TGFβ interaction or overexpression of DCN could serve as promising therapeutic strategies for GC patients.

Tumor inhibition or tumor promotion? The duplicity of CXCR3 in cancer

Tumor tissue includes cancer cells and normal stromal cells such as vascular endothelial cells, connective tissue cells (cancer associated fibroblast, mesenchymal stem cell), and immune cells (tumor-infiltrating lymphocytes or TIL, dendritic cells, eosinophils, basophils, mast cells, tumor-associated macrophages or TAM, myeloid-derived suppressor cells or MDSC). Anti-tumor activity is mainly mediated by infiltration of NK cells, Th1 and CD8⁺ T cells, and correlates with expression of NK cell and T cell attracting chemokines. Nevertheless, cancer cells hijack tissue homeostasis through secretion of cytokines and chemokines that mediate not only the induction of an inflamed status that supports cancer cell survival and growth, but also the recruitment and/or activation of immune suppressive cells. CXCL9, CXCL10, and CXCL11 are known for their tumor-inhibiting properties, but their overexpression in several hematologic and solid tumors correlates with disease severity, suggesting a role in tumor promotion. The dichotomous nature of CXCR3 ligands activity mainly depends on several molecular mechanisms induced by cancer cells themselves able to divert immune responses and to alter the whole local environment. A deep understanding of the nature of such phenomenon may provide a rationale to build up a CXCR3/ligand axis targeting strategy. In this review, we will discuss the role of CXCR3 in cancer progression and in regulation of anti-tumor immune response and immunotherapy.

Genetically predicted levels of circulating cytokines and prostate cancer risk: A Mendelian randomization study

Inflammation is considered to play a pivotal role in the pathogenesis of cancer, and observational studies have reported a relationship between circulating inflammation markers and the risk of prostate cancer. Using summary data of >140 000 individuals, two-sample Mendelian randomization (MR) analyses were performed to evaluate whether circulating levels of 27 cytokines and growth factors have a causal effect on the risk of developing prostate cancer. Genetically predicted elevated levels of monocyte chemotactic protein-1 (MCP-1) were associated with an increased risk of prostate cancer (odds ratio (OR) per 1 SD increase = 1.06, 95% confidence interval (CI): 1.04-1.09) at Bonferroni-adjusted level of significance (P < 1.85 × 10^-3). Results were stable across sensitivity analyses, and there was no evidence of directional pleiotropy. Under MR assumptions, our findings suggested a risk-increasing effect of circulating MCP-1 levels on prostate cancer. Whether targeting MCP-1 or its downstream effectors are useful in reducing prostate cancer incidence needs further investigation.

Identification of F5 as a Prognostic Biomarker in Patients with Gastric Cancer

Association of Coagulation factor V (F5) polymorphisms with the occurrence of many types of cancers has been widely reported, but whether it is of prognostic relevance in some cancers remain to be resolved. The RNA-sequencing dataset was downloaded from The Cancer Genome Atlas (TCGA). The potential of F5 genes to predict the survival time of gastric cancer (GC) patients was investigated using univariate and multivariate survival analysis whereas "Kaplan-Meier plotter" (KM-plotter) online tools were employed to validate the outcomes. TCGA data revealed that F5 mRNA levels were significantly upregulated in gastric cancer samples. Survival analysis confirmed that high levels of F5 mRNA correlated with short overall survival (OS) in gastric cancer patients, and the area under the curve (AUC) values of 1-, 2-, and 5-year OS rate were 0.554, 0.593, and 0.603, respectively. Survival analysis by KM-plotter indicated that the high expression of F5 mRNA was significantly associated with a shorter OS compared with the low expression level in all patients with GC, and this was also the case for patients in stage III (hazard ratio (HR) = 1.78, P = 0.017). These findings suggest that the F5 gene is significantly upregulated in GC tumour tissues, and may be a potential prognostic biomarker for GC.

PCSK6 Is a Key Protease in the Control of Smooth Muscle Cell Function in Vascular Remodeling

RATIONALE

PCSKs (Proprotein convertase subtilisins/kexins) are a protease family with unknown functions in vasculature. Previously, we demonstrated PCSK6 upregulation in human atherosclerotic plaques associated with smooth muscle cells (SMCs), inflammation, extracellular matrix remodeling, and mitogens.

OBJECTIVE

Here, we applied a systems biology approach to gain deeper insights into the PCSK6 role in normal and diseased vessel wall.

METHODS AND RESULTS

Genetic analyses revealed association of intronic PCSK6 variant rs1531817 with maximum internal carotid intima-media thickness progression in high-cardiovascular risk subjects. This variant was linked with PCSK6 mRNA expression in healthy aortas and plaques but also with overall plaque SMA+ cell content and pericyte fraction. Increased PCSK6 expression was found in several independent human cohorts comparing atherosclerotic lesions versus healthy arteries, using transcriptomic and proteomic datasets. By immunohistochemistry, PCSK6 was localized to fibrous cap SMA+ cells and neovessels in plaques. In human, rat, and mouse intimal hyperplasia, PCSK6 was expressed by proliferating SMA+ cells and upregulated after 5 days in rat carotid balloon injury model, with positive correlation to PDGFB (platelet-derived growth factor subunit B) and MMP (matrix metalloprotease) 2/MMP14. Here, PCSK6 was shown to colocalize and cointeract with MMP2/MMP14 by in situ proximity ligation assay. Microarrays of carotid arteries from Pcsk6^-/- versus control mice revealed suppression of contractile SMC markers, extracellular matrix remodeling enzymes, and cytokines/receptors. Pcsk6^-/- mice showed reduced intimal hyperplasia response upon carotid ligation in vivo, accompanied by decreased MMP14 activation and impaired SMC outgrowth from aortic rings ex vivo. PCSK6 silencing in human SMCs in vitro leads to downregulation of contractile markers and increase in MMP2 expression. Conversely, PCSK6 overexpression increased PDGFBB (platelet-derived growth factor BB)-induced cell proliferation and particularly migration.

CONCLUSIONS

PCSK6 is a novel protease that induces SMC migration in response to PDGFB, mechanistically via modulation of contractile markers and MMP14 activation. This study establishes PCSK6 as a key regulator of SMC function in vascular remodeling. Visual Overview: An online visual overview is available for this article.

Impact Effect of Methyl Tertiary-Butyl Ether "Twelve Months Vapor Inhalation Study in Rats"

We investigated the early risk of developing cancer by inhalation of low doses (60 µL/day) of methyl tertiary butyl ether (MTBE) vapors using protein SDS-PAGE and LC-MS/MS analysis of rat sera. Furthermore, histological alterations were assessed in the trachea and lungs of 60 adult male Wistar rats. SDS-PAGE of blood sera showed three protein bands corresponding to 29, 28, and 21 kDa. Mass spectroscopy was used to identify these three bands. The upper and middle protein bands showed homology to carbonic anhydrase 2 (CA II), whereas the lower protein band showed homology with peroxiredoxin 2. We found that exposure to MTBE resulted in histopathological alterations in the trachea and the lungs. The histological anomalies of trachea and lung showed that the lumen of trachea, bronchi, and air alveoli packed with free and necrotic epithelial cells (epithelialization). The tracheal lamina propria of lung demonstrated aggregation of lymphoid cells, lymphoid hyperplasia, hemorrhage, adenomas, fibroid degeneration, steatosis, foam cells, severe inflammatory cells with monocytic infiltration, edema, hemorrhage. Occluded, congested, and hypertrophied lung arteries in addition, degenerated thyroid follicles, were observed. The hyaline cartilage displayed degeneration, deformation, and abnormal protrusion. In conclusion, our results suggest that inhalation of very low concentrations of the gasoline additive MTBE could induce an increase in protein levels and resulted in histopathological alterations of the trachea and the lungs.

Apolipoproteins and cancer

The role of apolipoproteins in cardiovascular disease has been well investigated, but their participation in cancer has only been explored in a few published studies which showed a close link with certain kinds of cancer. In this review, we focused on the function of different kinds of apolipoproteins in cancers, autophagy, oxidative stress, and drug resistance. The potential application of apolipoproteins as biomarkers for cancer diagnosis and prognosis was highlighted, together with an investigation of their potential as drug targets for cancer treatment. Many important roles of apolipoproteins and their mechanisms in cancers were reviewed in detail and future perspectives of apolipoprotein research were discussed.

Multifaceted Roles of Asporin in Cancer: Current Understanding

The small leucine-rich proteoglycan (SLRP) family consists of 18 members categorized into five distinct classes, the traditional classes I–III, and the non-canonical classes IV–V. Unlike the other class I SLRPs (decorin and biglycan), asporin contains a unique and conserved stretch of aspartate (D) residues in its N terminus, and germline polymorphisms in the D-repeat-length are associated with osteoarthritis and prostate cancer progression. Since the first discovery of asporin in 2001, previous studies have focused mainly on its roles in bone and joint diseases, including osteoarthritis, intervertebral disc degeneration and periodontal ligament mineralization. Recently, asporin gene expression was also reported to be dysregulated in tumor tissues of different types of cancer, and to act as oncogene in pancreatic, colorectal, gastric, and prostate cancers, and some types of breast cancer, though it is also reported to function as a tumor suppressor gene in triple-negative breast cancer. Furthermore, asporin is also positively or negatively correlated with tumor proliferation, migration, invasion, and patient prognosis through its regulation of different signaling pathways, including the TGF-β, EGFR, and CD44 pathways. In this review, we seek to elucidate the signaling pathways and functions regulated by asporin in different types of cancer and to highlight some important issues that require investigation in future research.

CXCL11 promotes tumor progression by the biased use of the chemokine receptors CXCR3 and CXCR7

The chemokine, CXCL11, is highly expressed in different solid tumors and controls tumor growth, metastasis, and lymphocyte infiltration. Although of potential clinical interest, it is presently unknown whether these tumor-promoting activities involve the CXCL11 receptors, CXCR3 and/or CXCR7. This issue is further intrigued by the fact that CXCR3 exists in the two functionally divergent splice variants, CXCR3A and CXCR3B, which exert pro- and anti-tumorigenic influences, respectively. To unravel the role of the various CXCL11 receptors in tumor progression, we have now defined their role in CXCL11-induced chemotaxis of the tumor cell lines, A549, C33-A, DLD-1, MDA-MB-231, and PC-3. CXCL11-induced cell migration was either sensitive to the CXCR3 antagonist, ÀMG487 (DLD-1), the CXCR7 antagonist, CCX771 (C33-A, PC-3), or both (A549, MDA-231). Moreover, in C33-A and PC-3 cells, but not in the other tumor cells, pharmacological activation and inhibition of CXCR3B prevented and potentiated CXCL11-induced cell migration, respectively. Both immunocytochemistry and Western blot analysis finally revealed that the observed cell type specific organization of the CXCL11 system is not the result of differences in expression levels or subcellular location of CXCL11 receptors. Our findings imply that the therapeutic use of CXCR3 antagonists in cancer patients requires exact knowledge of the organization of the CXCR3 system in the respective tumor.

Insights into cerumen and application in diagnostics: past, present and future prospective

Cerumen or earwax is an emerging bio-fluid in clinical diagnosis that has been very little exploited during the past decades in spite of its high diagnostic potential. It is highly abundant in diagnostic biomarkers such as genetic material, lipids, proteins, chemical elements, internal and external metabolites (e.g. hormones, volatile organic compounds, amino acids, xenobiotics etc.) reaching earwax from the blood circulation. Thus, it is able to reflect not only physiology, pathophysiology of the human body but can also detect recent and long term exposure to environmental pollutants, without the need of invasive blood tests and in the same time overcoming many disadvantages faced by using other diagnostic biological fluids. This review discusses the biology, functions, chemistry of earwax, past and current approaches for the study of its chemical composition, emphasizing how a detected variation in its composition can offer information of high clinical value, which can be useful in diagnosis of many diseases such as metabolic disorders and tumours as well as in forensic applications. It also presents details about techniques of sample collection, storage, and analysis. Moreover, it highlights concerns about the use of earwax for diagnostic purposes, which should be addressed to make earwax diagnostics a reality in the future.

Cytoplasmic Asporin promotes cell migration by regulating TGF-β/Smad2/3 pathway and indicates a poor prognosis in colorectal cancer

Previous studies revealed that Asporin (ASPN) is a potential mediator in the development of various types of cancer as a secreted stroma protein, but the function of ASPN inside the cancer cells remains largely unknown. Here, we demonstrated a higher expression level of ASPN in colorectal cancer (CRC) than matched normal tissues, and 25% (2/8) CRC showed copy number variation (CNV) gain/amplification in ASPN gene. Both higher ASPN expression levels and ASPN CNV gain/amplification indicated a worse prognosis in CRC patients. ASPN can promote proliferation, migration, and invasion of CRC cells, and inhibit apoptosis by activating Akt/Erk and TGF-β/Smad2/3 signalings. Further investigations revealed that ASPN interacts with Smad2/3, facilitates its translocation into nucleus, and up-regulates the expression of Epithelial-mesenchymal transition (EMT) related genes. Rescue assays confirmed that TGF-β signaling is essential for the effects of ASPN on promoting CRC cell migration and invasion. In conclusion, ASPN promotes the migration and invasion of CRC cells via TGF-β/Smad2/3 pathway and could serve as a potential prognostic biomarker in CRC patients.

Identification of Potential Key Genes Associated With the Pathogenesis and Prognosis of Gastric Cancer Based on Integrated Bioinformatics Analysis

Background and Objective: Despite striking advances in multimodality management, gastric cancer (GC) remains the third cause of cancer mortality globally and identifying novel diagnostic and prognostic biomarkers is urgently demanded. The study aimed to identify potential key genes associated with the pathogenesis and prognosis of GC.

Methods: Differentially expressed genes between GC and normal gastric tissue samples were screened by an integrated analysis of multiple gene expression profile datasets. Key genes related to the pathogenesis and prognosis of GC were identified by employing protein–protein interaction network and Cox proportional hazards model analyses.

Results: We identified nine hub genes (TOP2A, COL1A1, COL1A2, NDC80, COL3A1, CDKN3, CEP55, TPX2, and TIMP1) which might be tightly correlated with the pathogenesis of GC. A prognostic gene signature consisted of CST2, AADAC, SERPINE1, COL8A1, SMPD3, ASPN, ITGBL1, MAP7D2, and PLEKHS1 was constructed with a good performance in predicting overall survivals.

Conclusion: The findings of this study would provide some directive significance for further investigating the diagnostic and prognostic biomarkers to facilitate the molecular targeting therapy of GC.

Subtype-specific clinical and prognostic relevance of tumor-expressed F5 and regulatory F5 variants in breast cancer: the CoCaV study

Essentials The role of coagulation factor V (encoded by F5) in cancer pathogenesis is unknown. The clinical significance of tumor-expressed F5 was evaluated in breast cancer patient cohorts. F5 was expressed in human breast tumors, and the expression was higher than in normal tissue. High F5 expression was associated with aggressive tumors, but also with survival in breast cancer.

SUMMARY

Background Tumor expression of certain coagulation factors has been linked to cancer progression. Single nucleotide polymorphisms (SNPs) in F5 (encoding the FV protein) have been found to be associated with breast cancer; however, the role of coagulation factor V (FV) in cancer pathogenesis remains undiscovered. Objectives We aimed to investigate the clinical significance of FV and the regulatory role of F5 gene variants in breast cancer. Patients/Methods A Scandinavian 503-sample breast cancer cohort and three public breast cancer datasets (GOBO, TCGA and KM plotter) were used to determine associations between F5 gene expression (tumor-specific), circulating FV, F5 SNPs, clinical characteristics and breast cancer survival. Immunohistochemistry (IHC) was used to detect FV antigen in tumors. Results F5 expression was 2-fold higher in breast tumors compared with normal tissue, and the presence of FV antigen in breast tumors was confirmed by IHC staining. F5 expression was increased in patients with hormone receptor negative tumors, triple negative tumors, HER2-enriched and basal-like tumors. In patients with basal tumors, high expression of F5 was associated with improved overall survival (hazard ratio, HR = 0.52, 95% confidence interval, 0.31-0.86). SNPs in F5 were associated with tumor size and luminal A tumors. The rs6427202-rs9332542 C-G haplotype, previously associated with breast cancer, displayed a cis-regulatory effect on F5 expression in tumors and plasma FV antigen levels. In silico mining supported this regulatory function. Conclusions FV was a possible marker of aggressive breast cancer, yet also a predictor of favorable outcome. Evaluation of FV expression may be clinically useful for prognosis and treatment decisions in aggressive breast cancer.

Asporin enhances colorectal cancer metastasis through activating the EGFR/src/cortactin signaling pathway

Asporin has been implicated as an oncogene in various types of human cancers; however, the roles of asporin in the development and progression of colorectal cancer (CRC) have not yet been determined. With clinical samples, we found that asporin was highly expressed in CRC tissues compared to adjacent normal tissues and the asporin expression levels were significantly associated with lymph node metastasis status and TNM stage of the patients. Through knockdown of asporin in CRC cell lines RKO and SW620 or overexpression of asporin in cell lines HT-29 and LoVo, we found that asporin could enhance wound healing, migration and invasion abilities of the CRC cells. Further more, with the human umbilical vein endothelial cells (HUVECs) tube formation assays and the xenograft model, we found that asporin promoted the tumor growth through stimulating the VEGF signaling pathway. The portal vein injection models suggested that asporin overexpression stimulated the liver metastasis of HT29 cell line, while asporin knockdown inhibited the liver metastasis of RKO cell line. In addition, asporin was found to augment the phosphorylation of EGFR/src/cortactin signaling pathway, which might be contributed to the biological functions of asporin in CRC metastasis. These results suggested that asporin promoted the tumor growth and metastasis of CRC, and it could be a potential therapeutic target for CRC patients in future.

The dual role of asporin in breast cancer progression

Asporin has been reported as a tumor suppressor in breast cancer, while asporin-activated invasion has been described in gastric cancer. According to our in silico search, high asporin expresion associates with significantly better relapse free survival (RFS) in patients with low-grade tumors but RFS is significantly worse in patients with grade 3 tumors. In line with other studies, we have confirmed asporin expression by RNA scope in situ hybridization in cancer associated fibroblasts. We have also found asporin expression in the Hs578T breast cancer cell line which we confirmed by quantitative RT-PCR and western blotting. From multiple testing, we found that asporin can be downregulated by bone morphogenetic protein 4 while upregulation may be facilited by serum-free cultivation or by three dimensional growth in stiff Alvetex scaffold. Downregulation by shRNA inhibited invasion of Hs578T as well as of CAFs and T47D cells. Invasion of asporin-negative MDA-MB-231 and BT549 breast cancer cells through collagen type I was enhanced by recombinant asporin. Besides other investigations, large scale analysis of aspartic acid repeat polymorphism will be needed for clarification of the asporin dual role in progression of breast cancer.

Integrating Discovery-driven Proteomics and Selected Reaction Monitoring To Develop a Noninvasive Assay for Geoduck Reproductive Maturation

Geoduck clams (Panopea generosa) are an increasingly important fishery and aquaculture product along the eastern Pacific coast from Baja California, Mexico, to Alaska. These long-lived clams are highly fecund, although sustainable hatchery production of genetically diverse larvae is hindered by the lack of sexual dimorphism, resulting in asynchronous spawning of broodstock, unequal sex ratios, and low numbers of breeders. The development of assays of gonad physiology could indicate sex and maturation stage as well as be used to assess the status of natural populations. Proteomic profiles were determined for three reproductive maturation stages in both male and female clams using data-dependent acquisition (DDA) of gonad proteins. Gonad proteomes became increasingly divergent between males and females as maturation progressed. The DDA data were used to develop targets analyzed with selected reaction monitoring (SRM) in gonad tissue as well as hemolymph. The SRM assay yielded a suite of indicator peptides that can be used as an efficient assay to determine geoduck gonad maturation status. Application of SRM in hemolymph samples demonstrates that this procedure could effectively be used to assess reproductive status in marine mollusks in a nonlethal manner.

Positional Scanning Identifies the Molecular Determinants of a High Affinity Multi-Leucine Inhibitor for Furin and PACE4

The proprotein convertase family of enzymes includes seven endoproteases with significant redundancy in their cleavage activity. We previously described the peptide Ac-LLLLRVK-Amba that displays potent inhibitory effects on both PACE4 and prostate cancer cell lines proliferation. Herein, the molecular determinants for PACE4 and furin inhibition were investigated by positional scanning using peptide libraries that substituted its leucine core with each natural amino acid. We determined that the incorporation of basic amino acids led to analogues with improved inhibitory potency toward both enzymes, whereas negatively charged residues significantly reduced it. All the remaining amino acids were in general well tolerated, with the exemption of the P6 position. However, not all of the potent PACE4 inhibitors displayed antiproliferative activity. The best analogues were obtained by the incorporation of the Ile residue at the P5 and P6 positions. These substitutions led to inhibitors with increased PACE4 selectivity and potent antiproliferative effects.

Asporin is a stromally expressed marker associated with prostate cancer progression

BACKGROUND

Prostate cancer shows considerable heterogeneity in disease progression and we propose that markers expressed in tumour stroma may be reliable predictors of aggressive tumour subtypes.

METHODS

We have used Kaplan-Meier, univariate and multivariate analysis to correlate the expression of Asporin (ASPN) mRNA and protein with prostate cancer progression in independent cohorts. We used immunohistochemistry and H scoring to document stromal localisation of ASPN in a tissue microarray and mouse prostate cancer model, and correlated expression with reactive stroma, defined using Masson Trichrome staining. We used cell cultures of primary prostate cancer fibroblasts treated with serum-free conditioned media from prostate cancer cell lines to examine regulation of ASPN mRNA in tumour stromal cells.

RESULTS

We observed increased expression of ASPN mRNA in a data set derived from benign vs tumour microdissected tissue, and a correlation with biochemical recurrence using Kaplan-Meier and Cox proportional hazard analysis. ASPN protein localised to tumour stroma and elevated expression of ASPN was correlated with decreased time to biochemical recurrence, in a cohort of 326 patients with a median follow up of 9.6 years. Univariate and multivariate analysis demonstrated that ASPN was correlated with progression, as were Gleason score, and clinical stage. Additionally, ASPN expression correlated with the presence of reactive stroma, suggesting that it may be a stromal marker expressed in response to the presence of tumour cells and particularly with aggressive tumour subtypes. We observed expression of ASPN in the stroma of tumours induced by p53 inhibition in a mouse model of prostate cancer, and correlation with neuroendocrine marker expression. Finally, we demonstrated that ASPN transcript expression in normal and cancer fibroblasts was regulated by conditioned media derived from the PC3, but not LNCaP, prostate cancer cell lines.

CONCLUSIONS

Our results suggest that ASPN is a stromally expressed biomarker that correlates with disease progression, and is observed in reactive stroma. ASPN expression in stroma may be part of a stromal response to aggressive tumour subtypes.

PACE4 regulates apoptosis in human pancreatic cancer Panc‑1 cells via the mitochondrial signaling pathway

Previous studies have demonstrated the overexpression of paired basic amino acid cleaving enzyme 4 (PACE4) mRNA in prostate cancer tissues. This overexpression is correlated with higher circulating protein levels in certain patients, however, the role of PACE4 in apoptosis and the potential molecular mechanisms of pancreatic cancer remain to be elucidated. The aim of the present study was to investigate the effect and potential molecular mechanisms of PACE4 on apoptosis in the Panc‑1 pancreatic cancer cell line. Cell proliferation was assessed using a Cell Counting Kit‑8 assay. Apoptotic nuclear shrinkage was monitored using Hoechst 33258 staining. Caspase‑3/7 activities were measured using a colorimetric caspase‑glo 3/7 assay. Alterations in protein expression were monitored using Western blot analysis. The results indicated that PACE4 small interfering (si)RNA inhibited cell proliferation and activated caspase‑3/7 activities. In addition, PACE4 siRNA significantly increased apoptosis via the activation of caspase‑3 and the downregulation of anti‑apoptotic proteins, X‑linked inhibitor of apoptosis protein and phosphorylated‑Akt. In addition, the results showed deregulation of the B cell lymphoma‑2 (Bcl‑2)-associated X protein/Bcl‑2 ratio which led to the release of cytochrome c following PACE4 siRNA transfection. In conclusion, PACE4 siRNA may exert antitumor activity through the mitochondrial pathway and is expected to be a promising therapeutic strategy for the treatment of pancreatic cancer.

Serum protein profiling in diffuse large B-cell lymphoma

PURPOSE

The aim of this pilot study was to conduct a nontargeted exploratory proteomics profiling analysis on sera obtained from patients diagnosed with diffuse large B-cell lymphoma (DLBCL) with the goal of identifying disease-specific biomarkers.

EXPERIMENTAL DESIGN

Sera from 87 participants (57 chemotherapy-naïve diffuse DLBCL patients, 30 controls frequency-matched by age group and World Health Organization (WHO) BMI categories) that were part of a large San Francisco Bay Area case-control study of non-Hodgkin lymphoma were analyzed by liquid chromatography combined with tandem mass spectrometry.

RESULTS

Thirty-five proteins (p-adjusted <0.05) were identified as differentially abundant between the DLBCL patients at various disease stages as compared to the controls. Of these, five proteins were randomly selected for further confirmation by ELISA: adiponectin (AdipoQ), cluster of differentiation 14 (CD14), heparin sulfate proteoglycan core protein (HSPG2), extracellular matrix 1 (ECM1), and alpha-1-antichymotrypsin (ACT). These proteins were statistically significantly elevated by 68.8, 37.0, 61.6, 68.0, and 32.0%, respectively, in DLBCL patient sera as compared to controls.

CONCLUSION AND CLINICAL RELEVANCE

These preliminary data when combined with other cancer-related data regarding these proteins warrant continued research in clinical and large prospective studies to clarify the role for these biomarkers in DLBCL pathogenesis and/or prognosis.

Glycoprotein asporin as a novel player in tumour microenvironment and cancer progression

BACKGROUND

Small leucine rich proteoglycans (SLRPs), major non-collagen components of the extracellular matrix (ECM), have multiple biological roles with diverse effects. Asporin, a member of the SLRPs class I, competes with other molecules in binding to collagen and affects its mineralization. Its role in cancer is only now being elucidated.

METHODS

The PubMed online database was used to search relevant reviews and original articles. Furthermore, altered asporin expression was analysed in publicly available genome-wide expression data at the Gene Expression Omnibus database.

RESULTS

Polymorphisms in the N-terminal polyaspartate domain, which binds calcium, are associated with osteoarthritis and prostate cancer. Asporin also promotes the progression of scirrhous gastric cancer where it is required for coordinated invasion by cancer associated fibroblasts and cancer cells. Besides the enhanced expression of asporin observed in multiple cancer types, such as breast, prostate, gastric, pancreas and colon cancer, tumour suppressive effects of asporin were described in triple-negative breast cancer. We also discuss a number of factors modulating asporin expression in different cell types relevant for alterations toing the tumour microenvironment.

CONCLUSION

The apparent contradicting tumour promoting and suppressive effects of asporin require further investigation. Deciphering the role of asporin and other SLRPs in tumour-stroma interactions is needed for a better understanding of cancer progression and potentially also for novel tumour microenvironment based therapies.

Proteomics analysis of vesicles isolated from plasma and urine of prostate cancer patients using a multiplex, aptamer-based protein array

Proteomics analysis of biofluid-derived vesicles holds enormous potential for discovering non-invasive disease markers. Obtaining vesicles of sufficient quality and quantity for profiling studies has, however, been a major problem, as samples are often replete with co-isolated material that can interfere with the identification of genuine low abundance, vesicle components. Here, we used a combination of ultracentrifugation and size-exclusion chromatography to isolate and analyse vesicles of plasma or urine origin. We describe a sample-handling workflow that gives reproducible, quality vesicle isolations sufficient for subsequent protein profiling. Using a semi-quantitative aptamer-based protein array, we identified around 1,000 proteins, of which almost 400 were present at comparable quantities in plasma versus urine vesicles. Significant differences were, however, apparent with elements like HSP90, integrin αVβ5 and Contactin-1 more prevalent in urinary vesicles, while hepatocyte growth factor activator, prostate-specific antigen–antichymotrypsin complex and many others were more abundant in plasma vesicles. This was also applied to a small set of specimens collected from men with metastatic prostate cancer, highlighting several proteins with the potential to indicate treatment refractory disease. The study provides a practical platform for furthering protein profiling of vesicles in prostate cancer, and, hopefully, many other disease scenarios.

PACE4 regulates apoptosis in human prostate cancer cells via endoplasmic reticulum stress and mitochondrial signaling pathways

BACKGROUND

PACE4 is a proprotein convertase capable of processing numerous substrates involved in tumor growth, invasion, and metastasis. However, the precise role of PACE4 during prostate cancer cell apoptosis has not been reported.

METHODS

In the present study, human prostate cancer cell lines DU145, LNCaP, and PC3 were transfected with PACE4 small interfering (si)RNA to investigate the underlying mechanisms of apoptosis.

RESULTS

We revealed that PACE4 siRNA exhibited antitumor activity by inducing apoptosis, as determined by Cell Counting Kit-8 (CCK-8), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet-razolium bromide (MTT) assay, cell cycle analysis, Hoechst staining, caspase-3/7 activity, and western blot analysis. In addition, PACE4 siRNA significantly increased the ratio of Bax/Bcl-2, which led to the release of cytochrome c. Moreover, PACE4 siRNA also induced endoplasmic reticulum stress by increasing the expression of GRP78, GRP94, p-PERK, and p-eIF2α. The ratio of Bax/Bcl-2 and GRP78 were also increased in PACE4 gene knockdown prostate cancer cells compared with the control cells.

CONCLUSION

These data demonstrate that PACE4 siRNA may exert its antitumor activity through mitochondrial and endoplasmic reticulum stress signaling pathways, indicating it may be a novel therapeutic target for prostate cancer.

Germline Variants in Asporin Vary by Race, Modulate the Tumor Microenvironment, and Are Differentially Associated with Metastatic Prostate Cancer

PURPOSE

Prostate cancers incite tremendous morbidity upon metastatic growth. We previously identified Asporin (ASPN) as a potential mediator of metastatic progression found within the tumor microenvironment. ASPN contains an aspartic acid (D)-repeat domain and germline polymorphisms in D-repeat-length have been associated with degenerative diseases. Associations of germline ASPN D polymorphisms with risk of prostate cancer progression to metastatic disease have not been assessed.

EXPERIMENTAL DESIGN

Germline ASPN D-repeat-length was retrospectively analyzed in 1,600 men who underwent radical prostatectomy for clinically localized prostate cancer and in 548 noncancer controls. Multivariable Cox proportional hazards models were used to test the associations of ASPN variations with risk of subsequent oncologic outcomes, including metastasis. Orthotopic xenografts were used to establish allele- and stroma-specific roles for ASPN D variants in metastatic prostate cancer.

RESULTS

Variation at the ASPN D locus was differentially associated with poorer oncologic outcomes. ASPN D14 [HR, 1.72; 95% confidence interval (CI), 1.05-2.81, P = 0.032] and heterozygosity for ASPN D13/14 (HR, 1.86; 95% CI, 1.03-3.35, P = 0.040) were significantly associated with metastatic recurrence, while homozygosity for the ASPN D13 variant was significantly associated with a reduced risk of metastatic recurrence (HR, 0.44; 95% CI, 0.21-0.94, P = 0.035) in multivariable analyses. Orthotopic xenografts established biologic roles for ASPN D14 and ASPN D13 variants in metastatic prostate cancer progression that were consistent with patient-based data.

CONCLUSIONS

We observed associations between ASPN D variants and oncologic outcomes, including metastasis. Our data suggest that ASPN expressed in the tumor microenvironment is a heritable modulator of metastatic progression.

Expression array analysis of the hepatocyte growth factor invasive program

Signaling by human hepatocyte growth factor (hHGF) via its cell surface receptor (MET) drives mitogenesis, motogenesis and morphogenesis in a wide spectrum of target cell types and embryologic, developmental and homeostatic contexts. Oncogenic pathway activation also contributes to tumorigenesis and cancer progression, including tumor angiogenesis and metastasis, in several prevalent malignancies. The HGF gene encodes full-length hHGF and two truncated isoforms known as NK1 and NK2. NK1 induces all three HGF activities at modestly reduced potency, whereas NK2 stimulates only motogenesis and enhances HGF-driven tumor metastasis in transgenic mice. Prior studies have shown that mouse HGF (mHGF) also binds with high affinity to human MET. Here we show that, like NK2, mHGF stimulates cell motility, invasion and spontaneous metastasis of PC3M human prostate adenocarcinoma cells in mice through human MET. To identify target genes and signaling pathways associated with motogenic and metastatic HGF signaling, i.e., the HGF invasive program, gene expression profiling was performed using PC3M cells treated with hHGF, NK2 or mHGF. Results obtained using Ingenuity Pathway Analysis software showed significant overlap with networks and pathways involved in cell movement and metastasis. Interrogating The Cancer Genome Atlas project also identified a subset of 23 gene expression changes in PC3M with a strong tendency for co-occurrence in prostate cancer patients that were associated with significantly decreased disease-free survival.

PACE4-based molecular targeting of prostate cancer using an engineered ⁶⁴Cu-radiolabeled peptide inhibitor

The potential of PACE4 as a pharmacological target in prostate cancer has been demonstrated as this proprotein convertase is strongly overexpressed in human prostate cancer tissues and its inhibition, using molecular or pharmacological approaches, results in reduced cell proliferation and tumor progression in mouse tumor xenograft models. We developed a PACE4 high-affinity peptide inhibitor, namely, the multi-leucine (ML), and sought to determine whether this peptide could be exploited for the targeting of prostate cancer for diagnostic or molecular imaging purposes. We conjugated a bifunctional chelator 1,4,7-triazacyclononane-1,4,7- triacetic acid (NOTA) to the ML peptide for copper-64 ((64)Cu) labeling and positron emission tomography (PET)- based prostate cancer detection. Enzyme kinetic assays against recombinant PACE4 showed that the NOTA-modified ML peptide displays identical inhibitory properties compared to the unmodified peptide. In vivo biodistribution of the (64)Cu/NOTA-ML peptide evaluated in athymic nude mice bearing xenografts of two human prostate carcinoma cell lines showed a rapid and high uptake in PACE4-expressing LNCaP tumor at an early time point and in PACE4-rich organs. Co-injection of unlabeled peptide confirmed that tumor uptake was target-specific. PACE4-negative tumors displayed no tracer uptake 15 minutes after injection, while the kidneys, demonstrated high uptake due to rapid renal clearance of the peptide. The present study supports the feasibility of using a (64)Cu/NOTA-ML peptide for PACE4-targeted prostate cancer detection and PACE4 status determination by PET imaging but also provides evidence that ML inhibitor-based drugs would readily reach tumor sites under in vivo conditions for pharmacological intervention or targeted radiation therapy.

A New Combinatorial Optimization Approach for Integrated Feature Selection Using Different Datasets: A Prostate Cancer Transcriptomic Study

Background

The joint study of multiple datasets has become a common technique for increasing statistical power in detecting biomarkers obtained from smaller studies. The approach generally followed is based on the fact that as the total number of samples increases, we expect to have greater power to detect associations of interest. This methodology has been applied to genome-wide association and transcriptomic studies due to the availability of datasets in the public domain. While this approach is well established in biostatistics, the introduction of new combinatorial optimization models to address this issue has not been explored in depth. In this study, we introduce a new model for the integration of multiple datasets and we show its application in transcriptomics.

Methods

We propose a new combinatorial optimization problem that addresses the core issue of biomarker detection in integrated datasets. Optimal solutions for this model deliver a feature selection from a panel of prospective biomarkers. The model we propose is a generalised version of the (α,β)-k-Feature Set problem. We illustrate the performance of this new methodology via a challenging meta-analysis task involving six prostate cancer microarray datasets. The results are then compared to the popular RankProd meta-analysis tool and to what can be obtained by analysing the individual datasets by statistical and combinatorial methods alone.

Results

Application of the integrated method resulted in a more informative signature than the rank-based meta-analysis or individual dataset results, and overcomes problems arising from real world datasets. The set of genes identified is highly significant in the context of prostate cancer. The method used does not rely on homogenisation or transformation of values to a common scale, and at the same time is able to capture markers associated with subgroups of the disease.

Asporin participates in gastric cancer cell growth and migration by influencing EGF receptor signaling

Asporin (ASPN), a novel member of the small leucine-rich proteoglycan (SLRP) family, serves as a key component of the tumor stroma and has been reported to be abnormally expressed in certain types of tumors. Specifically, the proteoglycan was proven to activate the coordinated invasion of scirrhous gastric cancer and cancer-associated fibroblasts. However, the role of ASPN in cancer cell growth and metastasis has not yet been addressed. In the present study, we aimed to evaluate the tumoricidal benefits of ASPN on tumorigenesis and progression of gastric cancer. Firstly, it was demonstrated that ASPN was overexpressed in gastric carcinoma tissues when compared to the corresponding non‑cancerous tissues, and it had varied levels of expression in gastric cancer epithelial cell lines. Additionally, we assessed the effects of transient siRNA‑mediated ASPN knockdown on gastric cancer cells. ASPN silencing inhibited proliferation and suppressed the migration of immortalized neoplastic epithelial cells. Furthermore, at the molecular level, we found that downregulation of ASPN blocked the anti-apoptotic molecule Bcl-2, increased the expression of pro-apoptotic molecule Bad, reduced the expression of migration-related proteins CD44 and matrix metalloproteinase (MMP)-2, and abrogated the activation of the phosphorylation status of ERK and epidermal growth factor (EGF) and its receptor (EGFR). Collectively, our findings indicate that ASPN is upregulated and plays an oncogenic role in gastric cancer progression and metastasis by influencing the EGFR signaling pathway.

Serum cytokine profile in patients with pancreatic cancer

OBJECTIVE

Pancreatic ductal adenocarcinoma is a deadly disease because of late diagnosis and chemoresistance. We aimed to find a panel of serum cytokines representing diagnostic and predictive biomarkers for pancreatic cancer.

METHODS

A cytokine antibody array was performed to simultaneously identify 507 cytokines in sera of patients with pancreatic cancer and healthy controls. The nonparametric Mann-Whitney U test was used to pairwise compare the controls, the pretreated patients, and the posttreated patients. Fold changes greater than or equal to 1.5 or less than or equal to 1/1.5 were considered significant. Receiver operating characteristic curves were used to assess the performance of the model. A leave-one-out cross-validation was used for estimating prediction error.

RESULTS

Comparing the sera of pretreated patients against the control samples, the cytokines fibroblast growth factor 10 (FGF-10/keratinocyte growth factor-2 (KGF-2), chemokine (C-X-C motif) ligand 11 interferon inducible T cell alpha chemokine (I-TAC)/chemokine [C-X-C motif] ligand 11 (CXCL11), oncostatin M (OSM), osteoactivin/glycoprotein nonmetastatic melanoma protein B, and stem cell factor (SCF) were found significantly overexpressed. Besides, the cytokines CD30 ligand/tumor necrosis factor superfamily, member 8 (TNFSF8), chordin-like 2, FGF-10/KGF-2, growth/differentiation factor 15, I-TAC/CXCL11, OSM, and SCF were differentially expressed in response to treatment.

CONCLUSIONS

We propose a role for FGF-10/KGF-2, I-TAC/CXCL11, OSM, osteoactivin/glycoprotein nonmetastatic melanoma protein B, and SCF as novel diagnostic biomarkers. CD30 ligand/TNFSF8, chordin-like 2, FGF-10/KGF-2, growth/differentiation factor 15, I-TAC/CXCL11, OSM, and SCF might represent as predictive biomarkers for gemcitabine and erlotinib response of patients with pancreatic cancer.

miR-124 exhibits antiproliferative and antiaggressive effects on prostate cancer cells through PACE4 pathway

INTRODUCTION

PACE4 plays an important role in prostate cancer (PCa) proliferation and aggression, which might provide a useful target against prostate cancer. In this study, we had strived to find some key miRNAs to decrease malignancy and invasiveness of PCa through regulating PACE4 expression.

METHODS

Clinically pathological analysis of immunohistochemistry/in situ hybridization was carried out to detect the relationship between PACE4 expression/miRNAs and the malignancy of prostate mass. Prostate cell lines (DU145, C4-2, and BPH-1) were cultured for growth curve, immunocytochemistry analysis, colony formation, Matrigel invasion, and transcriptional/translational expression assay of PACE4-related signaling molecules for confirming the relationship. MiRNAs targeting PACE4 were predicted, validated and further-corroborated using bio-software, real-time PCR, luciferase reporter assay and transfection of miRNA mimics and inhibitor.

RESULTS

It was suggested that PACE4 might reflect the pathological malignancy of prostate lesion from pathology analysis. Moreover, DU145 cells, the highest PACE4-level and related TF expression indicated of the strongest malignancy and invasiveness. It was significantly found that miR-124 was presented with the biggest odd to target PACE4-3'UTR, the capability of decreasing PACE expression and slowing down cell growth and cell invasion.

CONCLUSIONS

It was clear that PACE4 level was closely associated with malignancy and invasiveness of PCa in vivo or in vitro MiR-124, played a crucial role inhibiting PACE4 transcription thus exhibiting obvious effects of antiproliferation and antiaggression of PCa.

The role of cancer-associated fibroblasts, solid stress and other microenvironmental factors in tumor progression and therapy resistance

Tumors are not merely masses of neoplastic cells but complex tissues composed of cellular and noncellular elements. This review provides recent data on the main components of a dynamic system, such as carcinoma associated fibroblasts that change the extracellular matrix (ECM) topology, induce stemness and promote metastasis-initiating cells. Altered production and characteristics of collagen, hyaluronan and other ECM proteins induce increased matrix stiffness. Stiffness along with tumor growth-induced solid stress and increased interstitial fluid pressure contribute to tumor progression and therapy resistance. Second, the role of immune cells, cytokines and chemokines is outlined. We discuss other noncellular characteristics of the tumor microenvironment such as hypoxia and extracellular pH in relation to neoangiogenesis. Overall, full understanding of the events driving the interactions between tumor cells and their environment is of crucial importance in overcoming treatment resistance and improving patient outcome.

Asporin activates coordinated invasion of scirrhous gastric cancer and cancer-associated fibroblasts

Scirrhous gastric cancer, which has the worst prognosis among the various types of gastric cancer, is highly invasive and associated with abundant stromal fibroblasts. Although cancer-associated fibroblasts (CAFs) have been proposed to generate a tumor-supportive extracellular matrix that promotes the expansion of this type of cancer, the molecular mechanisms by which CAFs assist cancer cells are not yet fully understood. Here, we show for the first time that Asporin, a small leucine-rich proteoglycan (SLRP), is predominantly expressed in CAFs, and has essential roles in promoting co-invasion of CAFs and cancer cells. CAFs of scirrhous gastric cancer possess high potential for invasion, and invasion by CAFs frequently proceeded invasion by cancer cells, both in vitro and in vivo. Expression of Asporin was induced in fibroblasts by exposure to gastric cancer cells. Asporin secreted from CAFs activates Rac1 via an interaction with CD44 and promotes invasion by CAFs themselves. Moreover, Asporin promoted invasion by neighboring cancer cells, via paracrine effects mediated by activation of the CD44-Rac1 pathway. These results suggest that Asporin is a unique SLRP that promotes progression of scirrhous gastric cancer and is required for coordinated invasion by CAFs and cancer cells. Therefore, Asporin may represent a new therapeutic target molecule for the development of drugs aimed at manipulating the cancer microenvironment.

Comparison of protein immunoprecipitation-multiple reaction monitoring with ELISA for assay of biomarker candidates in plasma

Quantitative analysis of protein biomarkers in plasma is typically done by ELISA, but this method is limited by the availability of high-quality antibodies. An alternative approach is protein immunoprecipitation combined with multiple reaction monitoring mass spectrometry (IP-MRM). We compared IP-MRM to ELISA for the analysis of six colon cancer biomarker candidates (metalloproteinase inhibitor 1 (TIMP1), cartilage oligomeric matrix protein (COMP), thrombospondin-2 (THBS2), endoglin (ENG), mesothelin (MSLN) and matrix metalloproteinase-9 (MMP9)) in plasma from colon cancer patients and noncancer controls. Proteins were analyzed by multiplex immunoprecipitation from plasma with the ELISA capture antibodies, further purified by SDS-PAGE, digested and analyzed by stable isotope dilution MRM. IP-MRM provided linear responses (r = 0.978–0.995) between 10 and 640 ng/mL for the target proteins spiked into a “mock plasma” matrix consisting of 60 mg/mL bovine serum albumin. Measurement variation (coefficient of variation at the limit of detection) for IP-MRM assays ranged from 2.3 to 19%, which was similar to variation for ELISAs of the same samples. IP-MRM and ELISA measurements for all target proteins except ENG were highly correlated (r = 0.67–0.97). IP-MRM with high-quality capture antibodies thus provides an effective alternative method to ELISA for protein quantitation in biological fluids.

Genes upregulated in prostate cancer reactive stroma promote prostate cancer progression in vivo

PURPOSE

Marked reactive stroma formation is associated with poor outcome in clinically localized prostate cancer. We have previously identified genes with diverse functions that are upregulated in reactive stroma. This study tests the hypothesis that expression of these genes in stromal cells enhances prostate cancer growth in vivo.

EXPERIMENTAL DESIGN

The expression of reactive stroma genes in prostate stromal cell lines was evaluated by reverse transcriptase (RT)-PCR and qRT-PCR. Genes were knocked down using stable expression of short-hairpin RNAs (shRNA) and the impact on tumorigenesis assessed using the differential reactive stroma (DRS) system, in which prostate stromal cell lines are mixed with LNCaP prostate cancer cells and growth as subcutaneous xenografts assessed.

RESULTS

Nine of 10 reactive stroma genes tested were expressed in one or more prostate stromal cell lines. Gene knockdown of c-Kit, Wnt10B, Bmi1, Gli2, or COMP all resulted in decreased tumorigenesis in the DRS model. In all tumors analyzed, angiogenesis was decreased and there were variable effects on proliferation and apoptosis in the LNCaP cells. Wnt10B has been associated with stem/progenitor cell phenotype in other tissue types. Using a RT-PCR array, we detected downregulation of multiple genes involved in stem/progenitor cell biology such as OCT4 and LIF as well as cytokines such as VEGFA, BDNF, and CSF2 in cells with Wnt10B knockdown.

CONCLUSIONS

These findings show that genes upregulated in prostate cancer-reactive stroma promote progression when expressed in prostate stromal cells. Moreover, these data indicate that the DRS model recapitulates key aspects of cancer cell/reactive stroma interactions in prostate cancer.

Profiling of atherosclerotic lesions by gene and tissue microarrays reveals PCSK6 as a novel protease in unstable carotid atherosclerosis

OBJECTIVE

Carotid plaque instability is a major cause of ischemic stroke, but detailed knowledge about underlying molecular pathways is still lacking. Here, we evaluated large-scale transcriptomic and protein expression profiling in a biobank of carotid endarterectomies followed by characterization of identified candidates, as a platform for discovery of novel proteins differentially regulated in unstable carotid lesions.

APPROACH AND RESULTS

Genes highly upregulated in symptomatic versus asymptomatic plaques were selected from Affymetrix microarray analyses (n=127 plaques), and tissue microarrays constructed from 34 lesions were assayed for 21 corresponding proteins by immunohistochemistry. Quantification of stainings demonstrated differential expression of CD36, CD137, and DOCK7 (P<0.05) in unstable versus stable lesions and the most significant upregulation of a proprotein convertase, PCSK6 (P<0.0001). Increased expression of PCSK6 in symptomatic lesions was verified by quantitative real-time polymerase chain reaction (n=233), and the protein was localized to smooth muscle α-actin positive cells and extracellular matrix of the fibrous cap by immunohistochemistry. PCSK6 expression positively correlated to genes associated with inflammation, matrix degradation, and mitogens in microarrays. Stimulation of human carotid smooth muscle cells in vitro with cytokines caused rapid induction of PCSK6 mRNA.

CONCLUSIONS

Using a combination of transcriptomic and tissue microarray profiling, we demonstrate a novel approach to identify proteins differentially expressed in unstable carotid atherosclerosis. The proprotein convertase PCSK6 was detected at increased levels in the fibrous cap of symptomatic carotid plaques, possibly associated with key processes in plaque rupture such as inflammation and extracellular matrix remodeling. Further studies are needed to clarify the role of PCSK6 in atherosclerosis.

Identification, prioritization, and evaluation of glycoproteins for aggressive prostate cancer using quantitative glycoproteomics and antibody-based assays on tissue specimens

Prostate cancer is highly heterogeneous in nature; while the majority of cases are clinically insignificant, some cases are lethal. Currently, there are no reliable screening methods for aggressive prostate cancer. Since most established serum and urine biomarkers are glycoproteins secreted or leaked from the diseased tissue, the current study seeks to identify glycoprotein markers specific to aggressive prostate cancer using tissue specimens. With LC-MS/MS glycoproteomic analysis, we identified 350 glycopeptides with 17 being altered in aggressive prostate cancer. ELISA assays were developed/purchased to evaluate four candidates, that is, cartilage oligomeric matrix protein (COMP), periostin, membrane primary amine oxidase (VAP-1), and cathepsin L, in independent tissue sets. In agreement with the proteomic analysis, we found that COMP and periostin expressions were significantly increased in aggressive prostate tumors while VAP-1 expression was significantly decreased in aggressive tumor. In addition, the expression of these proteins in prostate metastases also follows the same pattern observed in the proteomic analysis. This study provides a workflow for biomarker discovery, prioritization, and evaluation of aggressive prostate cancer markers using tissue specimens. Our data suggest that increase in COMP and periostin and decrease in VAP-1 expression in the prostate may be associated with aggressive prostate cancer.

The Multi-Leu peptide inhibitor discriminates between PACE4 and furin and exhibits antiproliferative effects on prostate cancer cells

The proprotein convertases (PCs) play an important role in protein precursor activation through processing at paired basic residues. However, significant substrate cleavage redundancy has been reported between PCs. The question remains whether specific PC inhibitors can be designed. This study describes the identification of the sequence LLLLRVKR, named Multi-Leu (ML)-peptide, that displayed a 20-fold selectivity on PACE4 over furin, two enzymes with similar structural characteristics. We have previously demonstrated that PACE4 plays an important role in prostate cancer and could be a druggable target. The present study demonstrates that the ML-peptide significantly reduced the proliferation of DU145 and LNCaP prostate cancer-derived cell lines and induced G₀/G₁ cell cycle arrest. However, the ML-peptide must enter the cell to inhibit proliferation. It is concluded that peptide-based inhibitors can yield specific PC inhibitors and that the ML-peptide is an important lead compound that could potentially have applications in prostate cancer.