Expression analysis of Barrett's esophagus-associated high-grade dysplasia in laser capture microdissected archival tissue

Effects of inducing apoptosis and inhibiting proliferation of siRNA on polyadenylate-binding protein-interacting protein 1 in tongue cell carcinoma

BACKGROUND

It has been reported that the polyadenylate-binding protein-interacting protein 1 (PAIP1) pathway is closely connected with the progression of some malignant tumors. Here we examined the potential functional mechanism of PAIP1 in tongue squamous cell carcinoma (TSCC).

METHODS

PAIP1 was knocked down in TSCC cell lines and proliferation and apoptosis in vitro analyzed. The molecular features of TSCC were determined using quantitative proteome and succinylome analyses. The results were confirmed in the mouse model.

RESULTS

PAIP1 promoted cell proliferation and inhibited apoptosis. Its knockdown decreased Ki67 and Pcna expressions and increased Bax/Bcl2 index and Caspase-3 expression. Bioinformatics analysis for proteomics revealed that PAIP1 knockdown correlated with the changes in differential protein expression.

CONCLUSIONS

Upregulation of PAIP1 induces cell proliferation and inhibits apoptosis in TSCC; PAIP1 might be a diagnostic biomarker and a significant drug target.

Expression profile and cellular localizations of mucin proteins, CK7, and cytoplasmic p27 in Barrett's esophagus and esophageal adenocarcinoma

PURPOSE

Barrett's esophagus is one of the main risk factors for increased incidence of esophageal adenocarcinoma. In this study, we studied protein expression levels and cellular localizations of MUC-1, MUC-2, MUC-5AC, CK7, and cytoplasmic p27 to assess the relationship between the expression of each of these proteins and the disease progression on endoscopic biopsies.

MATERIALS AND METHODS

Immunohistochemical analyses were performed using antibodies produced against MUC-1, MUC-2, MUC-5AC, CK7, and p27. Endoscopic specimens of esophageal mucosa were obtained from 72 patients who underwent esophagectomy for Barrett's esophagus, metaplasia, dysplasia, or esophageal adenocarcinoma developed from Barrett's esophagus.

RESULTS

Multilayer squamous epithelium showed only MUC-1 positivity in the EAC group while MUC-2 and MUC-5AC staining could not be detected in this group. Strong and diffused membranous or cytoplasmic staining of CK7 was observed at squamous, ductal, surface columnar and/or glandular epithelium. c-p27 staining was diffused and moderate in the cellular membranes observed in all groups except for esophageal epithelial metaplasia without intestinal metaplasia. Additionally, weakly focal cytoplasmic staining in squamous epithelium of p27 in EAC was detected.

CONCLUSIONS

Barrett's esophagus, which has a heterogeneous epithelium, might yield different diagnosis based on endoscopic evaluation and immunohistological investigation. Thus, the use of MUC1, p27, and CK7 might strengthen the truthful diagnosis. MUC-1, CK7, and c-p27 immunostaining can be used as the predictive markers for esophageal cancer progression from Barrett's esophagus.

FABP1 and Hepar expression levels in Barrett's esophagus and associated neoplasia in an Asian population

INTRODUCTION

Barrett's esophagus (BE) is a premalignant condition associated with esophageal adenocarcinoma (EAC). Evidence highlights that EAC is associated with an estimated 5-year survival of approximately 10-15%. Therefore, there is a need to determine which biomarkers are of value in the diagnosis of BE and beyond. The aim of our study was to evaluate the clinical significance of markers known to be expressed across BE and associated neoplasia.

METHODS

Retrospective tissues were obtained from columnar lined esophagus (CLE) without goblet cells (n=22), BE (n=29), dysplasia (n=14), and EAC (n=10). Standardised immunohistochemistry for FABP1, Hepar, CDH17, and CDX2 were performed followed by quantitative staining and statistical analysis.

RESULTS

FABP1 expression was negligible in CLE and was highest in BE, with a further decrease in expression in dysplasia and EAC. Hepar expression was also negligible in CLE and was highest in dysplasia and BE, with a reduced expression in EAC. CDH17 and CDX2 showed a significantly higher expression in BE, dysplasia, and EAC compared to CLE.

CONCLUSION

All 4 markers were excellent diagnostic panels to clearly discriminate BE from CLE. Moreover, as FABP1 and Hepar have different expression levels in dysplasia and EAC, these markers could function as key diagnostic aids in helping to determine the state of disease progression.

A nonrandomized trial of vitamin D supplementation for Barrett's esophagus

Background

Vitamin D deficiency may increase esophageal cancer risk. Vitamin D affects genes regulating proliferation, apoptosis, and differentiation and induces the tumor suppressor 15-hydroxyprostaglandin dehydrogenase (PGDH) in other cancers. This nonrandomized interventional study assessed effects of vitamin D supplementation in Barrett’s esophagus (BE). We hypothesized that vitamin D supplementation may have beneficial effects on gene expression including 15-PGDH in BE.

Methods

BE subjects with low grade or no dysplasia received vitamin D₃ (cholecalciferol) 50,000 international units weekly plus a proton pump inhibitor for 12 weeks. Esophageal biopsies from normal plus metaplastic BE epithelium and blood samples were obtained before and after vitamin D supplementation. Serum 25-hydroxyvitamin D was measured to characterize vitamin D status. Esophageal gene expression was assessed using microarrays.

Results

18 study subjects were evaluated. The baseline mean serum 25-hydroxyvitamin D level was 27 ng/mL (normal ≥30 ng/mL). After vitamin D supplementation, 25-hydroxyvitamin D levels rose significantly (median increase of 31.6 ng/mL, p<0.001). There were no significant changes in gene expression from esophageal squamous or Barrett’s epithelium including 15-PGDH after supplementation.

Conclusion

BE subjects were vitamin D insufficient. Despite improved vitamin D status with supplementation, no significant alterations in gene expression profiles were noted. If vitamin D supplementation benefits BE, a longer duration or higher dose of supplementation may be needed.

Immature myeloid progenitors promote disease progression in a mouse model of Barrett's-like metaplasia

Cdx2, an intestine specific transcription factor, is expressed in Barrett's esophagus (BE). We sought to determine if esophageal Cdx2 expression would accelerate the onset of metaplasia in the L2-IL-1β transgenic mouse model for Barrett's-like metaplasia. The K14-Cdx2::L2-IL-1β double transgenic mice had half as many metaplastic nodules as control L2-IL-1β mice. This effect was not due to a reduction in esophageal IL-1β mRNA levels nor diminished systemic inflammation. The diminished metaplasia was due to an increase in apoptosis in the K14-Cdx2::L2-IL-1β mice. Fluorescence activated cell sorting of immune cells infiltrating the metaplasia identified a population of CD11b+Gr-1+ cells that are significantly reduced in K14-Cdx2::L2-IL-1β mice. These cells have features of immature granulocytes and have immune-suppressing capacity. We demonstrate that the apoptosis in K14-Cdx2::L2-IL-1β mice is CD8+ T cell dependent, which CD11b+Gr-1+ cells are known to inhibit. Lastly, we show that key regulators of CD11b+Gr-1+ cell development, IL-17 and S100A9, are significantly diminished in the esophagus of K14-Cdx2::L2-IL-1β double transgenic mice. We conclude that metaplasia development in this mouse model for Barrett's-like metaplasia requires suppression of CD8+ cell dependent apoptosis, likely mediated by immune-suppressing CD11b+Gr-1+ immature myeloid cells.

Deregulation of SYCP2 predicts early stage human papillomavirus-positive oropharyngeal carcinoma: A prospective whole transcriptome analysis

This study was designed to identify significant differences in gene expression profiles of human papillomavirus (HPV)‐positive and HPV‐negative oropharyngeal squamous cell carcinomas (OPSCC) and to better understand the functional and biological effects of HPV infection in the premalignant pathway. Twenty‐four consecutive patients with locally advanced primary OPSCC were included in a prospective clinical trial. Fresh tissue samples (tumor vs. matched normal epithelium) were subjected to whole transcriptome analysis and the results validated on the same cohort with RT–quantitative real‐time PCR. In a separate retrospective cohort of 27 OPSCC patients, laser capture microdissection of formalin‐fixed, paraffin‐embedded tissue allowed RNA extraction from adjacent regions of normal epithelium, carcinoma in situ (premalignant) and invasive SCC tissue. The majority of patients showed evidence of high‐risk HPV16 positivity (80.4%). Predictable fold changes of RNA expression in HPV‐associated disease included multiple transcripts within the p53 oncogenic pathway (e.g. CDKN2A/CCND1). Other candidate transcripts found to have altered levels of expression in this study have not previously been established (SFRP1, CRCT1, DLG2, SYCP2, and CRNN). Of these, SYCP2 showed the most consistent fold change from baseline in premalignant tissue; aberrant expression of this protein may contribute to genetic instability during HPV‐associated cancer development. If further corroborated, this data may contribute to the development of a non‐invasive screening tool. This study is registered with the UK Clinical Research Network (ref.: 11945).

Identification and validation of potential new biomarkers for prostate cancer diagnosis and prognosis using 2D-DIGE and MS

This study was designed to identify and validate potential new biomarkers for prostate cancer and to distinguish patients with and without biochemical relapse. Prostate tissue samples analyzed by 2D-DIGE (two-dimensional difference in gel electrophoresis) and mass spectrometry (MS) revealed downregulation of secernin-1 (P < 0.044) in prostate cancer, while vinculin showed significant upregulation (P < 0.001). Secernin-1 overexpression in prostate tissue was validated using Western blot and immunohistochemistry while vinculin expression was validated using immunohistochemistry. These findings indicate that secernin-1 and vinculin are potential new tissue biomarkers for prostate cancer diagnosis and prognosis, respectively. For validation, protein levels in urine were also examined by Western blot analysis. Urinary vinculin levels in prostate cancer patients were significantly higher than in urine from nontumor patients (P = 0.006). Using multiple reaction monitoring-MS (MRM-MS) analysis, prostatic acid phosphatase (PAP) showed significant higher levels in the urine of prostate cancer patients compared to controls (P = 0.012), while galectin-3 showed significant lower levels in the urine of prostate cancer patients with biochemical relapse, compared to those without relapse (P = 0.017). Three proteins were successfully differentiated between patients with and without prostate cancer and patients with and without relapse by using MRM. Thus, this technique shows promise for implementation as a noninvasive clinical diagnostic technique.

Disrupting the Indian hedgehog signaling pathway in vivo attenuates surgically induced osteoarthritis progression in Col2a1-CreERT2; Ihhfl/fl mice

INTRODUCTION

Previous observations implicate Indian hedgehog (Ihh) signaling in osteoarthritis (OA) development because it regulates chondrocyte hypertrophy and matrix metallopeptidase 13 (MMP-13) expression. However, there is no direct genetic evidence for the role of Ihh in OA, because mice with cartilage or other tissue-specific deletion of the Ihh gene die shortly after birth. We evaluated the role of Ihh in vivo via a Cre-loxP-mediated approach to circumvent the early death caused by Ihh deficiency.

METHODS

To evaluate the role of Ihh in OA development, Ihh was specifically deleted in murine cartilage using an Ihh conditional deletion construct (Col2a1-CreER(T2); Ihh(fl/fl)). The extent of cartilage degradation and OA progression after Ihh deletion was assessed by histological analysis, immunohistochemistry, real-time PCR and in vivo fluorescence molecular tomography (FMT) 2 months after OA was induced by partial medial meniscectomy. The effect of Ihh signaling on cartilage was compared between Ihh-deleted mice and their control littermates.

RESULTS

Only mild OA changes were observed in Ihh-deleted mice, while control mice displayed significantly more cartilage damage. Typical OA markers such as type X collagen and MMP-13 were decreased in Ihh-deleted mice. In vivo FMT demonstrated decreased cathepsins and MMP activity in knee joints of animals with deletion of Ihh.

CONCLUSIONS

These findings support the protective role of Ihh deletion in surgically induced OA. Thus, our findings suggest the potential to develop new therapeutic strategies that can prevent and treat OA by inhibiting Ihh signaling in chondrocytes.

Laser-assisted microdissection in translational research: theory, technical considerations, and future applications

Molecular profiling already exerts a profound influence on biomedical research and disease management. Microdissection technologies contribute to the molecular profiling of diseases, enabling investigators to probe genetic characteristics and dissect functional physiology within specific cell populations. Laser-capture microdissection (LCM), in particular, permits collation of genetic, epigenetic, and gene expression differences between normal, premalignant, and malignant cell populations. Its selectivity for specific cell populations promises to greatly improve the diagnosis and management of many human diseases. LCM has been extensively used in cancer research, contributing to the understanding of tumor biology by mutation detection, clonality analysis, epigenetic alteration assessment, gene expression profiling, proteomics, and metabolomics. In this review, we focus on LCM applications for DNA, RNA, and protein analysis in specific cell types and on commercially available LCM platforms. These analyses could clinically be used as aids to cancer diagnosis, clinical management, genomic profile studies, and targeted therapy. In this review, we also discuss the technical details of tissue preparation, analytical yields, tissue selection, and selected applications using LCM.

Early diagnostic biomarkers for esophageal adenocarcinoma--the current state of play

Esophageal adenocarcinoma (EAC) is one of the two most common types of esophageal cancer with alarming increase in incidence and very poor prognosis. Aiming to detect EAC early, currently high-risk patients are monitored using an endoscopic-biopsy approach. However, this approach is prone to sampling error and interobserver variability. Diagnostic tissue biomarkers related to genomic and cell-cycle abnormalities have shown promising results, although with current technology these tests are difficult to implement in the screening of high-risk patients for early neoplastic changes. Differential miRNA profiles and aberrant protein glycosylation in tissue samples have been reported to improve performance of existing tissue-based diagnostic biomarkers. In contrast to tissue biomarkers, circulating biomarkers are more amenable to population-screening strategies, due to the ease and low cost of testing. Studies have already shown altered circulating glycans and DNA methylation in BE/EAC, whereas disease-associated changes in circulating miRNA remain to be determined. Future research should focus on identification and validation of these circulating biomarkers in large-scale trials to develop in vitro diagnostic tools to screen population at risk for EAC development.

[Subjective grading of Barrett's neoplasia by pathologists: correlation with objective histomorphometric variables]

Even though pathologists are trained to recognize the same histological features for the diagnosis and grading of different histological images, not all pathologists are influenced to a similar level of intensity by the same morphological characteristics of the tissue when scoring Barrett's dysplasia/neoplasia. The variables which most pathologists have intuitively chosen to use for scoring of the severity of Barrett's changes are mainly those related to the general tissue architecture, such as nuclear crowding, orientation and stratification. Interestingly, nuclear size is not used by most pathologists but nuclear pleomorphism and symmetry does influence a significant number of pathologists. Maybe the most difficult variables for the human eye to recognize are variables of chromatin texture (such as margination or heterogeneity), the predictive importance of which has been demonstrated in a previously published work. Textural variables may therefore remain the subject of a computerized analysis. Nevertheless, the fact that a few pathologists do actually correlate with nuclear texture in scoring, argues in favor of making further attempts to train pathologists to also rely on texture, similar to cytologists, when scoring Barrett's dysplasia.

Review of S100A9 biology and its role in cancer

S100A9 is a calcium binding protein with multiple ligands and post-translation modifications that is involved in inflammatory events and the initial development of the cancer cell through to the development of metastatic disease. This review has a threefold purpose: 1) describe the S100A9 structural elements important for its biological activity, 2) describe the S100A9 biology in the context of the immune system, and 3) illustrate the role of S100A9 in the development of malignancy via interactions with the immune system and other cellular processes.

The association between the preoperative serum levels of lipocalin-2 and matrix metalloproteinase-9 (MMP-9) and prognosis of breast cancer

Background

Although a number of experimental studies have suggested the role of lipocalin-2 (LCN2) and matrix metalloproteinase-9 (MMP-9) in breast cancer progression, limited numbers of epidemiological studies have examined the relationship between the levels of lipocalin-2 and MMP-9 and breast cancer survival.

Methods

Preoperative serum levels of lipocalin-2 and MMP-9 were measured in 303 breast cancer patients and 74 healthy controls recruited between 2004 and 2007. We examined the association between lipocalin-2 and MMP-9 levels and disease-free survival (DFS) using Cox proportional hazard regression model.

Results

The serum levels of lipocalin-2 and MMP-9 were not significantly different between patients and controls (P > 0.05). Elevated lipocalin-2 and MMP-9 levels were associated with reduced DFS of breast cancer ( P_trend = 0.029 and P_trend = 0.063, respectively). When lipocalin-2 and MMP-9 levels were categorized based on the combined risk score, patients with higher levels of both lipocalin-2 and MMP-9 exhibited poor DFS compared to patients with lower levels (P_trend = 0.004). Furthermore, these effects were profound in patients with BMI less than 25 kg/m² (adjusted hazard ratio (aHR), 3.17; 95% confidence intervals (CI), 1.66-6.06, P_trend < 0.001) or lymph-node negative breast cancer (aHR, 5.36; 95% CI, 2.18-13.2, P_trend < 0.001).

Conclusions

Our study suggests that the elevated levels of lipocalin-2 and MMP-9 are associated with reduced breast cancer survival, particularly in patients with lower BMI and lymph-node negative breast cancers.

Medical and endoscopic management of high-grade dysplasia in Barrett's esophagus

The management of high-grade dysplasia in Barrett's esophagus has clearly changed over recent years. The risk of cancer development is still substantial, with about one in three patients developing cancer, but a number of patients do not develop cancer. The nature of high-grade dysplasia has also been genetically elucidated with more evidence of chromosomal instability being present at this stage than previously thought. Therapy of the condition has evolved more toward endoscopic therapy, given the good results of radio-frequency ablation and photodynamic therapy in eliminating dysplasia and decreasing cancer development in randomized controlled trial. The best candidates for treatment include compliant patients that have relatively short segments of Barrett's esophagus, an anatomically straight segment, lack of nodularity, and an intact p16. However, even with excellent long-term results similar to surgical resection, the risk of recurrence is present in over 14% of patients, which indicates that there will be a need to continue surveillance endoscopy in these patients.

LCM assisted biomarker discovery from archival neoplastic gastrointestinal tissues

Expression array analysis of epithelial mRNA to identify biomarkers of premalignant and malignant conditions in the gastrointestinal (GI) tract is an area of intense study. Archived formalin-fixed paraffin-embedded (FFPE) tissues documenting these changes are readily available and should be a valuable resource for retrospective analysis. Laser capture microdissection of defined areas of epithelial cells at different stages of neoplastic progression is described together with methods for prequalification of RNA in FFPE tissue blocks selected for analysis. Paradise reagents specifically designed for isolation and amplification of RNA from FFPE archival tissue specimens are used to prepare probes for the human X3P microarray from Affymetrix.

Whole genome expression array profiling highlights differences in mucosal defense genes in Barrett's esophagus and esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) has become a major concern in Western countries due to rapid rises in incidence coupled with very poor survival rates. One of the key risk factors for the development of this cancer is the presence of Barrett's esophagus (BE), which is believed to form in response to repeated gastro-esophageal reflux. In this study we performed comparative, genome-wide expression profiling (using Illumina whole-genome Beadarrays) on total RNA extracted from esophageal biopsy tissues from individuals with EAC, BE (in the absence of EAC) and those with normal squamous epithelium. We combined these data with publically accessible raw data from three similar studies to investigate key gene and ontology differences between these three tissue states. The results support the deduction that BE is a tissue with enhanced glycoprotein synthesis machinery (DPP4, ATP2A3, AGR2) designed to provide strong mucosal defenses aimed at resisting gastro-esophageal reflux. EAC exhibits the enhanced extracellular matrix remodeling (collagens, IGFBP7, PLAU) effects expected in an aggressive form of cancer, as well as evidence of reduced expression of genes associated with mucosal (MUC6, CA2, TFF1) and xenobiotic (AKR1C2, AKR1B10) defenses. When our results are compared to previous whole-genome expression profiling studies keratin, mucin, annexin and trefoil factor gene groups are the most frequently represented differentially expressed gene families. Eleven genes identified here are also represented in at least 3 other profiling studies. We used these genes to discriminate between squamous epithelium, BE and EAC within the two largest cohorts using a support vector machine leave one out cross validation (LOOCV) analysis. While this method was satisfactory for discriminating squamous epithelium and BE, it demonstrates the need for more detailed investigations into profiling changes between BE and EAC.

TOPOIIalpha and HER-2/neu overexpression/amplification in Barrett's oesophagus, dysplasia and adenocarcinoma

Rossi E, Villanacci V, Bassotti G, Donato F, Festa A, Cengia G, Grisanti S & Cestari R (2010) Histopathology57, 81–89 TOPOIIα and HER-2/neu overexpression/amplification in Barrett’s oesophagus, dysplasia and adenocarcinoma

Predicting Neoplastic Progression in Barrett's Esophagus

Patients with Barrett's esophagus have a significantly increased risk of esophageal adenocarcinoma, 40-125 times higher than the general population. Since only a small fraction of Barrett's esophagus patients will actually progress to esophageal adenocarcinoma, there is a need to develop markers that may accurately predict which patients with Barrett's esophagus are likely to have aggressive disease and progress to cancer versus patients who will remain histologically stable and have a benign course. This would allow for better risk stratification of patients with Barrett's esophagus in order to target aggressive surveillance and intervention towards only those patients at highest risk for neoplastic progression. Predictive biomarkers may thus have significant clinical utility in the management of Barrett's esophagus patients. The detection of dysplasia in esophageal biopsies is currently the only standard method used in clinical practice as a marker for increased risk of cancer. However, dysplasia has not been a accurate or reliable marker for predicting malignant progression and suffers from poor interobserver agreement among pathologists and sampling error. A multitude of potential biomarkers have been studied over the years. It is likely that the best model for predicting progression to esophageal adenocarcinoma in Barrett's esophagus patients will ultimately involve a combination of biomarkers, dysplasia grade and other pathological characteristics, as well as clinical and demographic attributes. In this review, we will discuss the most promising biomarkers that have been studied thus far.

Stimulation of chondrocyte hypertrophy by chemokine stromal cell-derived factor 1 in the chondro-osseous junction during endochondral bone formation

During endochondral bone formation, chondrocytes undergo differentiation toward hypertrophy before they are replaced by bone and bone marrow. In this study, we found that a G-protein coupled receptor CXCR4 is predominantly expressed in hypertrophic chondrocytes, while its ligand, chemokine stromal cell-derived factor 1 (SDF-1) is expressed in the bone marrow adjacent to hypertrophic chondrocytes. Thus, they are expressed in a complementary pattern in the chondro-osseous junction of the growth plate. Transfection of a CXCR4 cDNA into pre-hypertrophic chondrocytes results in a dose-dependent increase of hypertrophic markers including Runx2, Col X, and MMP-13 in response to SDF-1 treatment. In organ culture SDF-1 infiltrates cartilage and accelerates growth plate hypertrophy. Furthermore, a continuous infusion of SDF-1 into the rabbit proximal tibial physis results in early physeal closure, which is accompanied by a transient elevation of type X collagen expression. Blocking SDF-1/CXCR4 interaction suppresses the expression of Runx2. Thus, interaction of SDF-1 and CXCR4 is required for Runx2 expression. Interestingly, knocking down Runx2 gene expression results in a decrease of CXCR4 mRNA levels in hypertrophic chondrocytes. This suggests a positive feedback loop of stimulation of chondrocyte hypertrophy by SDF-1/CXCR4, which is mediated by Runx2.

Proteomic profiling of the retinal dysplasia and degeneration chick retina

PURPOSE

In our previous paper we undertook proteomic analysis of the normal developing chick retina to identify proteins that were differentially expressed during retinal development. In the present paper we use the same proteomic approach to analyze the development and onset of degeneration in the retinal dysplasia and degeneration (rdd) chick. The pathology displayed by the rdd chick resembles that observed in some of the more severe forms of human retinitis pigmentosa.

METHODS

Two-dimensional gel electrophoresis (pH 4-7), gel image analysis, and mass spectrometry were used to profile the developing and degenerating retina of the rdd and wild-type (wt) chick retina.

RESULTS

Several proteins were identified by mass spectrometry that displayed differential expression between normal and rdd retina between embryonic day 12 (E12) and post-hatch day 1 (P1). Secernin 1 displayed the most significant variation in expression between rdd and wt retina; this may be due to differential phosphorylation in the rdd retina. Secernin 1 has dipeptidase activity and has been demonstrated to play a role in exocytosis; it has been shown to be overexpressed in certain types of cancer and has also been suggested as a potential neurotoxicologically relevant target. Its role in the retina and in particular its differential expression in the degenerate rdd retina remains unknown and will require further investigation. Other proteins that were differentially expressed in the rdd retina included valosin-containing protein, beta-synuclein, stathmin 1, nucleoside diphosphate kinase, histidine triad nucleotide-binding protein, and 40S ribosomal protein S12. These proteins are reported to be involved in several cellular processes, including the ubiquitin proteasome pathway, neuroprotection, metastatic suppression, transcriptional and translational regulation, and regulation of microtubule dynamics.

CONCLUSIONS

This proteomic study is the first such investigation of the rdd retina and represents a unique data set that has revealed several proteins that are differentially expressed during retinal degeneration in the rdd chick. Secernin 1 showed the most significant differences in expression during this degeneration period. Further investigation of the proteins identified may provide insight into the complex events underlying retinal degeneration in this animal model.

Lipocalin 2: a multifaceted modulator of human cancer

Lipocalin 2 (Lcn2), a member of the lipocalin family that transports small lipophilic ligands, has gained recent attention as both a potential biomarker and a modulator of human cancers. Here we describe recent findings of the functions of Lcn2 in breast cancer and the potential mechanisms that underlie its actions. Lcn2 has been shown to induce the epithelial to mesenchymal transition (EMT) in breast cancer cells and to promote breast tumor invasion. Estrogen receptor alpha may participate in the pathway that leads to Lcn2-induced EMT. Preliminary evidence also suggests that Lcn2 may be useful as a potential non-invasive urinary biomarker of breast cancer. Elevated levels of Lcn2 have also been reported in other human cancers. The potential roles of Lcn2 in epithelial tumors as well as leukemia are also reviewed and discussed here.