Loss of annexin A1 expression in human breast cancer detected by multiple high-throughput analyses

The Immune Response of Cancer Cells in Breast and Gynecologic Neoplasms

Cancer diseases constitute a major health problem which leads to the death of millions of people annually. They are unique among other diseases because cancer cells can perfectly adapt to the environment that they create themselves. This environment is usually highly hostile and for normal cells it would be hugely difficult to survive, however neoplastic cells not only can survive but also manage to proliferate. One of the reasons is that they can alter immunological pathways which allow them to be flexible and change their phenotype to the one needed in specific conditions. The aim of this paper is to describe some of these immunological pathways that play significant roles in gynecologic neoplasms as well as review recent research in this field. It is of high importance to possess extensive knowledge about these processes, as greater understanding leads to creating more specialized therapies which may prove highly effective in the future.

Exosomal Serum Biomarkers as Predictors for Laryngeal Carcinoma

BACKGROUND

The lack of screening methods for LSCC is a critical issue, as treatment options and the treatment outcome greatly depend on the stage of LSCC at initial diagnosis. Therefore, the objective of this study was to identify potential exosomal serum biomarkers that can diagnose LSCC and distinguish between early- and late-stage disease.

METHODS

A multiplexed proteomic array was used to identify differentially expressed proteins in exosomes isolated from the serum samples of LSCC patients compared to the control group (septorhinoplasty, SRP). The most promising proteins for diagnosis and differentiation were calculated using biostatistical methods and were validated by immunohistochemistry (IHC), Western blots (WB), and ELISA.

RESULTS

Exosomal insulin-like growth factor binding protein 7 (IGFBP7) and Annexin A1 (ANXA1) were the most promising exosomal biomarkers for distinguishing between control and LSCC patients and also between different stages of LSCC (fold change up to 15.9, p < 0.001 for all).

CONCLUSION

The identified proteins represent potentially novel non-invasive biomarkers. However, these results need to be validated in larger cohorts with a long-term follow-up. Exosomal biomarkers show a superior signal-to-noise ratio compared to whole serum and may therefore be an important tool for non-invasive biomarker profiling for laryngeal carcinoma in the future.

Suppression of VEGF and inflammatory cytokines, modulation of Annexin A1 and organ functions by galloylquinic acids in breast cancer model

The ongoing development of novel drugs for breast cancer aims to improve therapeutic outcomes, reduce toxicities, and mitigate resistance to chemotherapeutic agents. Doxorubicin (Dox) is known for its significant side effects caused by non-specific cytotoxicity. In this study, we investigated the antitumor activity of galloylquinic acids (BF) and the beneficial role of their combination with Dox in an Ehrlich ascites carcinoma (EAC)-bearing mouse model, as well as their cytotoxic effect on MCF-7 cells. The EAC-mice were randomized into five experimental groups: normal saline, Dox (2 mg/kg, i.p), BF (150 mg/kg, orally), Dox and BF combined mixture, and a control group. Mice were subjected to a 14-day treatment regimen. Results showed that BF compounds exerted chemopreventive effects in EAC mice group by increasing mean survival time, decreasing tumor volume, inhibiting ascites tumor cell count, modulating body weight changes, and preventing multi-organ histopathological alterations. BF suppressed the increased levels of inflammatory mediators (IL-6 and TNF-α) and the angiogenic marker VEGF in the ascitic fluid. In addition, BF and their combination with Dox exhibited significant cytotoxic activity on MCF-7 cells by inhibiting cell viability and modulating Annexin A1 level. Moreover, BF treatments could revert oxidative stress, restore liver and kidney functions, and normalize blood cell counts.

A Dominant-Negative Mutant of ANXA7 Impairs Calcium Signaling and Enhances the Proliferation of Prostate Cancer Cells by Downregulating the IP3 Receptor and the PI3K/mTOR Pathway

Annexin A7/ANXA7 is a calcium-dependent membrane fusion protein with tumor suppressor gene (TSG) properties, which is located on chromosome 10q21 and is thought to function in the regulation of calcium homeostasis and tumorigenesis. However, whether the molecular mechanisms for tumor suppression are also involved in the calcium- and phospholipid-binding properties of ANXA7 remain to be elucidated. We hypothesized that the 4 C-terminal endonexin-fold repeats in ANXA7 (GX(X)GT), which are contained within each of the 4 annexin repeats with 70 amino acids, are responsible for both calcium- and GTP-dependent membrane fusion and the tumor suppressor function. Here, we identified a dominant-negative triple mutant (DNTM/DN-ANXA7J) that dramatically suppressed the ability of ANXA7 to fuse with artificial membranes while also inhibiting tumor cell proliferation and sensitizing cells to cell death. We also found that the [DNTM]ANA7 mutation altered the membrane fusion rate and the ability to bind calcium and phospholipids. In addition, in prostate cancer cells, our data revealed that variations in phosphatidylserine exposure, membrane permeabilization, and cellular apoptosis were associated with differential IP3 receptor expression and PI3K/AKT/mTOR modulation. In conclusion, we discovered a triple mutant of ANXA7, associated with calcium and phospholipid binding, which leads to the loss of several essential functions of ANXA7 pertinent to tumor protection and highlights the importance of the calcium signaling and membrane fusion functions of ANXA7 for preventing tumorigenesis.

Cytotoxicity and growth-inhibiting activity of Astragalus polysaccharides against breast cancer via the regulation of EGFR and ANXA1

Astragalus polysaccharide (APS) has been frequently used as an adjuvant agent responsible for its immunoregulatory activity to enhance efficacy and reduce toxicity of chemotherapy used in the management of breast cancer. However, the other synergism mechanism of APS remains unclear. This study was performed to evaluate the potential targets and possible mechanism behind APS in vivo direct anti-tumor activity on breast cancer. Multiple biological detections were conducted to investigate the protein and mRNA expression levels of key targets. In total, 116 down-regulated and 73 up-regulated differential expressed genes (DEGs) were examined from 7 gene expression datasets. Top ten hub genes were obtained in four typical protein-protein interaction (PPI) network of DEGs involved in each specific biological process (BP, cell cycle, cell proliferation, cell apoptosis and death) that was related to inhibitory activity of APS in vitro against breast cancer cell lines. Four common DEGs (EGFR, ANXA1, KIF14 and IGF1) were further identified in the above four BP-PPI networks, among which EGFR and ANXA1 were the hub genes that were potentially linked to the progression of breast cancer. The results of biological detections indicated that the expression of EGFR in breast cancer cells was down-regulated, while the expression of ANXA1 was markedly increased in response to APS. In conclusion, the present study may provide potential molecular therapeutic targets and a new insight into the mechanism of APS against breast cancer.

Therapeutic potential of targeting HSPA5 through dual regulation of two candidate prognostic biomarkers ANXA1 and PSAT1 in osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor that mostly affects young people's health. The prognosis of patients with unresectable or recurrent osteosarcoma still remains dismal. Based on gene integration analysis from GEO and TARGET databases by R language, the differentially expressed genes of osteosarcoma patients were identified. Biological molecular function analysis indicated that these genes were importantly enriched in the process of cell adhesion molecule binding. Gene significance highly-related to clinical traits of osteosarcoma was found by weighted gene co-expression network analysis. Additionally, receiver operating characteristic curve analysis was conducted to find prognostic markers in LASSO Cox regression model. Two candidate biomarkers, ANXA1 and PSAT1, for the prognosis of osteosarcoma were detected separately on the basis of WGCNA and LASSO model. Of note, their expression profiles were interrelated with an important therapeutic target HSPA5. In vitro pharmaceutical experiments were performed to explore the biological role and prognostic benefit of candidates. Suppression of HSPA5 effectively upregulated ANXA1 and inhibited PSAT1, resulting in osteosarcoma cell proliferation arrest and apoptosis. These findings suggest that HSPA5 serves as a core molecule for osteosarcoma therapy due to its bidirectional regulation of candidate prognostic biomarkers ANXA1 and PSAT1.

Contribution of annexin A1 to anticancer immunosurveillance

Mouse cancers lacking the expression of annexin A1 (ANXA1) fail to respond to immunogenic chemotherapies. This has been initially explained by the requirement of extracellular ANXA1 (which is released from dying cancer cells) to engage formyl peptide receptor-1 (FPR1) on dendritic cells (DC) for the establishment of corpse/DC synapses. Here, we show that ANXA1-deficent cancer cells exhibit a defect in the exposure of calreticulin (CALR), which is an important "eat-me" signal, facilitating the phagocytic uptake of dead-cell antigens by DC. Of note, intratumoral injection of recombinant CALR protein was able to restore the therapeutic response of ANXA1-deficient cancers to anthracycline-based chemotherapy. Carcinomas developing in patients tend to downregulate ANXA1 expression as compared to their normal tissues of origin. ANXA1-low breast, colorectal, lung and kidney cancers are scarcely infiltrated by DC and cytotoxic T lymphocytes, supporting the idea that ANXA1 deficiency facilitates immune escape. We propose that such ANXA1-low cancers might be particularly suitable to local immunotherapy with CALR protein.

Identification and prognostic value of anterior gradient protein 2 expression in breast cancer based on tissue microarray

Breast cancer has attracted substantial attention as one of the major cancers causing death in women. It is crucial to find potential biomarkers of prognostic value in breast cancer. In this study, the expression pattern of anterior gradient protein 2 in breast cancer was identified based on the main molecular subgroups. Through analysis of 69 samples from the Gene Expression Omnibus database, we found that anterior gradient protein 2 expression was significantly higher in non-triple-negative breast cancer tissues compared with normal tissues and triple-negative breast cancer tissues (p < 0.05). The data from a total of 622 patients from The Cancer Genome Atlas were analysed. The data from The Cancer Genome Atlas and results from quantitative reverse transcription polymerase chain reaction also verified the anterior gradient protein 2 expression pattern. Furthermore, we performed immunohistochemical analysis. The quantification results revealed that anterior gradient protein 2 is highly expressed in non-triple-negative breast cancer (grade 3 excluded) and grade 1 + 2 (triple-negative breast cancer excluded) tumours compared with normal tissues. Anterior gradient protein 2 was significantly highly expressed in non-triple-negative breast cancer (grade 3 excluded) and non-triple-negative breast cancer tissues compared with triple-negative breast cancer tissues (p < 0.01). In addition, anterior gradient protein 2 was significantly highly expressed in grade 1 + 2 (triple-negative breast cancer excluded) and grade 1 + 2 tissues compared with grade 3 tissues (p < 0.05). Analysis by Fisher's exact test revealed that anterior gradient protein 2 expression was significantly associated with histologic type, histological grade, oestrogen status and progesterone status. Univariate analysis of clinicopathological variables showed that anterior gradient protein 2 expression, tumour size and lymph node status were significantly correlated with overall survival in patients with grade 1 and 2 tumours. Cox multivariate analysis revealed anterior gradient protein 2 as a putative independent indicator of unfavourable outcomes (p = 0.031). All these data clearly showed that anterior gradient protein 2 is highly expressed in breast cancer and can be regarded as a putative biomarker for breast cancer prognosis.

Comparative proteome analysis of human esophageal cancer and adjacent normal tissues

Objective(s):

Ranking as the sixth commonest cancer, esophageal squamous cell carcinoma (ESCC) represents one of the leading causes of cancer death worldwide. One of the main reasons for the low survival of patients with esophageal cancer is its late diagnosis.

Materials and Methods:

We used proteomics approach to analyze ESCC tissues with the aim of a better understanding of the malignant mechanism and searching candidate protein biomarkers for early diagnosis of esophageal cancer. The differential protein expression between cancerous and normal esophageal tissues was investigated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Then proteins were identified by matrix-assisted laser desorption/ ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) and MASCOT web based search engine.

Results:

We reported 4 differentially expressed proteins involved in the pathological process of esophageal cancer, such as annexinA1 (ANXA1), peroxiredoxin-2 (PRDX2), transgelin (TAGLN) andactin-aortic smooth muscle (ACTA2).

Conclusion:

In this report we have introduced new potential biomarker (ACTA2). Moreover, our data confirmed some already known markers for EC in our region.

Hydrophobic Fractionation Enhances Novel Protein Detection by Mass Spectrometry in Triple Negative Breast Cancer

It is widely believed that discovery of specific, sensitive and reliable tumor biomarkers can improve the treatment of cancer. The goal of this study was to develop a novel fractionation protocol targeting hydrophobic proteins as possible cancer cell membrane biomarkers. Hydrophobic proteins of breast cancer tissues and cell lines were enriched by polymeric reverse phase columns. The retained proteins were eluted and digested for peptide identification by nano-liquid chromatography with tandem mass spectrometry using a hybrid linear ion-trap Orbitrap.Hundreds of proteins were identified from each of these three specimens: tumors, normal breast tissue, and breast cancer cell lines. Many of the identified proteins defined key cellular functions. Protein profiles of cancer and normal tissues from the same patient were systematically examined and compared. Stem cell markers were overexpressed in triple negative breast cancer (TNBC) compared with non-TNBC samples. Because breast cancer stem cells are known to be resistant to radiation and chemotherapy, and can be the source of metastasis frequently seen in patients with TNBC, our study may provide evidence of molecules promoting the aggressiveness of TNBC.The initial results obtained using a combination of hydrophobic fractionation and nano-LC mass spectrometry analysis of these proteins appear promising in the discovery of potential cancer biomarkers. When sufficiently refined, this approach may prove useful for early detection and better treatment of breast cancer.

Increased cathepsin D protein expression is a biomarker for osteosarcomas, pulmonary metastases and other bone malignancies

Cancer proteomics provide a powerful approach to identify biomarkers for personalized medicine. Particularly, biomarkers for early detection, prognosis and therapeutic intervention of bone cancers, especially osteosarcomas, are missing. Initially, we compared two-dimensional gel electrophoresis (2-DE)-based protein expression pattern between cell lines of fetal osteoblasts, osteosarcoma and pulmonary metastasis derived from osteosarcoma. Two independent statistical analyses by means of PDQuest® and SameSpot® software revealed a common set of 34 differentially expressed protein spots (p < 0.05). 17 Proteins were identified by mass spectrometry and subjected to Ingenuity Pathway Analysis resulting in one high-ranked network associated with Gene Expression, Cell Death and Cell-To-Cell Signaling and Interaction. Ran/TC4-binding protein (RANBP1) and Cathepsin D (CTSD) were further validated by Western Blot in cell lines while the latter one showed higher expression differences also in cytospins and in clinical samples using tissue microarrays comprising osteosarcomas, metastases, other bone malignancies, and control tissues. The results show that protein expression patterns distinguish fetal osteoblasts from osteosarcomas, pulmonary metastases, and other bone diseases with relevant sensitivities between 55.56% and 100% at ≥87.50% specificity. Particularly, CTSD was validated in clinical material and could thus serve as a new biomarker for bone malignancies and potentially guide individualized treatment regimes.

Proteomic Analysis of Urine to Identify Breast Cancer Biomarker Candidates Using a Label-Free LC-MS/MS Approach

INTRODUCTION

Breast cancer is a complex heterogeneous disease and is a leading cause of death in women. Early diagnosis and monitoring progression of breast cancer are important for improving prognosis. The aim of this study was to identify protein biomarkers in urine for early screening detection and monitoring invasive breast cancer progression.

METHOD

We performed a comparative proteomic analysis using ion count relative quantification label free LC-MS/MS analysis of urine from breast cancer patients (n = 20) and healthy control women (n = 20).

RESULTS

Unbiased label free LC-MS/MS-based proteomics was used to provide a profile of abundant proteins in the biological system of breast cancer patients. Data analysis revealed 59 urinary proteins that were significantly different in breast cancer patients compared to the normal control subjects (p<0.05, fold change >3). Thirty-six urinary proteins were exclusively found in specific breast cancer stages, with 24 increasing and 12 decreasing in their abundance. Amongst the 59 significant urinary proteins identified, a list of 13 novel up-regulated proteins were revealed that may be used to detect breast cancer. These include stage specific markers associated with pre-invasive breast cancer in the ductal carcinoma in-situ (DCIS) samples (Leucine LRC36, MAST4 and Uncharacterized protein CI131), early invasive breast cancer (DYH8, HBA, PEPA, uncharacterized protein C4orf14 (CD014), filaggrin and MMRN2) and metastatic breast cancer (AGRIN, NEGR1, FIBA and Keratin KIC10). Preliminary validation of 3 potential markers (ECM1, MAST4 and filaggrin) identified was performed in breast cancer cell lines by Western blotting. One potential marker MAST4 was further validated in human breast cancer tissues as well as individual human breast cancer urine samples with immunohistochemistry and Western blotting, respectively.

CONCLUSIONS

Our results indicate that urine is a useful non-invasive source of biomarkers and the profile patterns (biomarkers) identified, have potential for clinical use in the detection of BC. Validation with a larger independent cohort of patients is required in the following study.

Upregulated Annexin A1 promotes cellular invasion in triple-negative breast cancer

Annexin A1 (ANXA1) is a calcium-dependent phospholipid-linked protein, involved in anti-inflammatory effects, regulation of cellular differentiation, proliferation and apoptosis. While many studies have investigated the ANXA1 expression in various tumor types, the role of ANXA1 is not fully understood. Therefore, in the present study, we evaluated the ANXA1 expression in 211 breast cancer patients and compared the levels with clinicopathological factors. ANXA1 was positively expressed in 31 (14.7%) of the 211 cases in our cohort, and these positive cases were associated with triple-negative breast cancer (TNBC) (P=0.007) and venous invasion (P=0.028). The in vitro cell experiment found that the MDA-MB-231 cell line, which is a TNBC cell line, highly expressed ANXA1. Using this cell line, the functional role of ANXA1 in breast cancer was revealed and the knockdown of ANXA1 by specific siRNA demonstrated a significant reduction in cellular invasion. Further experiments indicated that ANXA1 was induced by hypoxia with hypoxia-inducible factor-1α induction. These results suggested that ANXA1, which enhanced breast cancer invasion and metastasis under hypoxia, were significantly associated with the worst patient outcome. This is particularly noted in TNBC, the group of breast cancer with the worst outcome for which new therapeutic implications are required.

Annexin A1 in malignant tumors: current opinions and controversies

Annexin A1 is a 37 kDa calcium and phospholipid-binding protein that participates in several biological processes, such as inflammatory reactions, modulation of cell proliferation, regulation of cell death signaling, apoptosis, and, most importantly, tumor formation and development. Although annexin A1 has been implicated in the biology of various tumors, the findings are highly controversial and information regarding the underlying mechanism remains limited. Moreover, the mechanism by which annexin A1 participates in carcinogenesis and tumor progression is rather unclear. In the current study, we review the important biological functions of annexin A1 in different tumors. This work indicates that annexin A1 is a possible target for novel therapeutic intervention and that it is a potential biomarker for tumor diagnosis and screening.

Mining genome sequencing data to identify the genomic features linked to breast cancer histopathology

BACKGROUND

Genetics and genomics have radically altered our understanding of breast cancer progression. However, the genomic basis of various histopathologic features of breast cancer is not yet well-defined.

MATERIALS AND METHODS

The Cancer Genome Atlas (TCGA) is an international database containing a large collection of human cancer genome sequencing data. cBioPortal is a web tool developed for mining these sequencing data. We performed mining of TCGA sequencing data in an attempt to characterize the genomic features correlated with breast cancer histopathology. We first assessed the quality of the TCGA data using a group of genes with known alterations in various cancers. Both genome-wide gene mutation and copy number changes as well as a group of genes with a high frequency of genetic changes were then correlated with various histopathologic features of invasive breast cancer.

RESULTS

Validation of TCGA data using a group of genes with known alterations in breast cancer suggests that the TCGA has accurately documented the genomic abnormalities of multiple malignancies. Further analysis of TCGA breast cancer sequencing data shows that accumulation of specific genomic defects is associated with higher tumor grade, larger tumor size and receptor negativity. Distinct groups of genomic changes were found to be associated with the different grades of invasive ductal carcinoma. The mutator role of the TP53 gene was validated by genomic sequencing data of invasive breast cancer and TP53 mutation was found to play a critical role in defining high tumor grade.

CONCLUSIONS

Data mining of the TCGA genome sequencing data is an innovative and reliable method to help characterize the genomic abnormalities associated with histopathologic features of invasive breast cancer.

Urine annexin A1 as an index for glomerular injury in patients

BACKGROUND

We recently demonstrated high urine levels of annexin A1 (ANXA1) protein in a mouse Adriamycin-induced glomerulopathy (ADG) model.

OBJECTIVE

To establish ANXA1 as a potential biomarker for glomerular injury in patients.

METHODS

A time-course study in the mouse ADG model, followed by renal tissues and urine samples from patients with various types of glomerular disorders for ANXA1.

RESULTS

Urinary ANXA1 protein was (1) detectable in both the ADG model and in patients except those with minimal change disease (MCD); (2) positively correlated with renal lesions in patients; and (3) early detectable in diabetes patients with normoalbuminuria.

CONCLUSIONS

ANXA1 is a universal biomarker that is helpful in the early diagnosis, prognostic prediction, and outcome monitoring of glomerular injury. Measurement of urinary ANXA1 protein levels can help in differentiating MCD from other types of glomerular disorders.

Potential role of Anxa1 in cancer

The annexins are a well-known, closely related, multigene superfamily of Ca2+-regulated, phospholipid-dependent, membrane-binding proteins. As a member of the annexins, Anxa1 participates in a variety of important biological processes, such as cellular transduction, membrane aggregation, inflammation, phagocytosis, proliferation, differentiation and apoptosis. Accumulated evidence has indicated that Anxa1 deregulations are associated with the development, invasion, metastasis, occurrence and drug resistance of cancers. The research evidence in recent years indicates that Anxa1 might specifically function either as a tumor suppressor or a tumor promoter candidate for certain cancers depending on the particular type of tumor cells/tissues. This article summarizes the associations between Anxa1 and malignant tumors, as well as potential action mechanisms. Anxa1 has the potential to be used in the future as a biomarker for the diagnosis, treatment and prognosis of certain tumors.

Proteomic profiling and interactome analysis of ER-positive/HER2/neu negative invasive ductal carcinoma of the breast: towards proteomics biomarkers

Breast cancer, especially ER positive/HER2/neu negative IDC, is the predominant subtype of invasive ductal carcinoma. Although proteomic approaches have been used towards biomarker discovery in clinical breast cancer, ER positive/HER2/neu negative IDC is the least studied subtype. To discover biomarkers, as well as to understand the molecular events associated with disease progression of estrogen receptor positive/HER2/neu negative subtype of invasive ductal carcinoma, differential protein expression profiling was performed by using LC-MS(E) (MS at elevated energy). A total of 118 proteins were identified, of which 26 were differentially expressed. These identified proteins were functionally classified and their interactions and coexpression were analyzed by using bioinformatic tools PANTHER (Protein Analysis THrough Evolutionary Relationships) and STRING (Search Tool for the Retrieval of Interacting Genes). These proteins were found to be upregulated and were involved in cytoskeletal organization, calcium binding, and stress response. Interactions of annexin A5, actin, S100 A10, glyceraldehyde 3 phosphate dehydrogenase, superoxide dismutase 1, apolipoprotein, fibrinogen, and heat shock proteins were prominent. Differential expression of these proteins was validated by two-dimensional gel electrophoresis and Western blot analysis. The cluster of these proteins may serve as a signature profile for estrogen receptor positive/ HER2/neu negative subtype.

Changes in proteomic profiles in different prostate lobes of male rats throughout growth and development and aging stages of the life span

BACKGROUND

Aging-related changes in important cellular pathways in the prostate may promote a permissive environment for an increased risk for prostatic disease development such as prostate cancer. Our objectives were to examine for such changes, by systematically determining the effects of growth and development and aging on proteomic profiles in different lobes of the rat prostate.

METHODS

Prostate lobes (dorsolateral lobe, DL and ventral lobe, VL) were obtained from male Fisher rats of various ages representing young (4 months), mature (12 months), old (18 months), and very old (24 months). Differentially expressed proteins between age groups in each lobe were identified using a proteomic approach, isobaric Tags for Relative and Absolute Quantitation (iTRAQ). Select changes in the DL and VL were verified by immunoblot analysis.

RESULTS

iTRAQ identified 317 proteins with high confidence. iTRAQ discovered 12 and 6 proteins significantly modulated in response to growth and development in the DL and VL, respectively, and 42 and 29 proteins significantly modulated in response to aging in the DL and VL, respectively. Proteins modulated during growth and development in the DL and VL are involved in a variety of biological processes including cell communication and development, whereas proteins modulated during aging were predominantly related to antioxidant activity and immunity. Immunoblot analysis verified age-related changes for α-1 antitrypsin, annexin A1, hypoxia up-regulated protein 1, and 78 kDa glucose-regulated protein.

CONCLUSIONS

Aging results in changes in numerous prostatic proteins and pathways which are mainly linked to inflammation and may lead to prostatic disease development.

Regulation of lung fibroblast activation by annexin A1

Annexin-A1 (AnxA1) is a glucocorticoid-induced protein with multiple actions in the regulation of inflammatory cell activation. The contribution of AnxA1 to human cell biology is not well understood. We investigated the contribution of AnxA1 and its receptor, formyl-peptide receptor 2 (FPR2), to the regulation of inflammatory responses in human normal lung fibroblasts (NLF). Silencing constitutive AnxA1 expression in NLF using small interfering RNA (siRNA) was associated with moderate but significant increases in tumor necrosis factor (TNF)-induced proliferation and interleukin (IL)-6 production, accompanied by reduction of ERK and NF-κB activity. AnxA1 regulation of ERK and NF-κB activation was associated with effects on proliferation. Blocking FPR2 using the specific antagonist WRW4 mimicked the effects of AnxA1 silencing on TNF-induced proliferation, IL-6, ERK, and NF-κB activation. AnxA1 silencing also impaired inhibitory effects of glucocorticoid on IL-6 production and on the expression of glucocorticoid-induced leucine zipper (GILZ), but blocking FPR2 failed to mimic these effects of AnxA1 silencing. These data suggest that AnxA1 regulates TNF-induced proliferation and inflammatory responses in lung fibroblasts, via effects on the ERK and NF-κB pathways, which depend on FPR2. AnxA1 also mediates effects of glucocorticoids and GILZ expression, but these effects appear independent of FPR2. These findings suggest that mimicking AnxA1 actions might have therapeutic potential in chronic inflammatory lung diseases.

Proteomic study explores AGR2 as pro-metastatic protein in HCC

Hepatocellular carcinoma (HCC) is one of the most common and aggressive malignant tumors worldwide. The prognosis of patients with HCC still remains very dismal, mainly due to metastasis. We found that high-expression levels of AGR2 existed in metastatic HCC cell lines and patient samples. Overexpression of AGR2 was found to be correlated to the metastatic status of HCC cells, and inhibition of AGR2 by siRNA resulted in a dramatic decline in invasion abilities in metastatic cells in vitro. Overexpression of AGR2 increased the invasion of HCC cells in vitro and also in vivo with a nude mouse model. The tandem affinity purification (TAP) identified 18 AGR2-binding proteins and IPA analysis revealed that these proteins focus on MAPK and Caspase pathway. Therefore, we speculate that the overexpression of AGR2 can promote HCC metastasis, possibly by affecting MAPK and Caspase pathway through AGR2-interacting proteins.

The role of annexin A1 in expression of matrix metalloproteinase-9 and invasion of breast cancer cells

Matrix metalloproteinase-9 (MMP-9) plays an important role in the invasion and metastasis of cancer cells. However, the regulatory mechanism of MMP-9 expression and its biological effects on breast cancer development remain obscure. In the current study, we examined the potential role of annexin A1 (ANXA1) in regulating migration and invasion in breast cancer cell lines. Both ANXA1 mRNA and protein are expressed in the highly invasive, hormone-insensitive human breast cancer cell lines MDA-MB-231 and SKBr3, but not in the hormone-responsive cell lines MCF-7 and T47D. Downregulation of ANXA1 expression with specific small interfering RNAs (ANXA1 siRNA) in MDA-MB-231 cells resulted in decreased cancer cell migration and invasion. Ablation of ANXA1 expression decreases the expression of MMP-9 at both the mRNA and protein levels and also reduces the proteolytic activity of MMP-9 in MDA-MB-231 cells. Moreover, silencing ANXA1 also decreases the transcriptional activity of MMP-9 by the suppression of nuclear factor kappa-B (NF-κB) activity. Collectively, these results indicate that ANXA1 functions as a positive regulator of MMP-9 expression and invasion of breast cancer cells through specific activation of the NF-κB signaling pathway.

Knockdown of AGR2 induces cellular senescence in prostate cancer cells

Anterior-gradient 2 (AGR2), overexpressed in many tumors including prostate cancer (PCa), is implicated in stimulation of cell proliferation, adhesion, anti-apoptosis and cell cycle regulation. Here, a potential role of AGR2 in cellular senescence was investigated. We first observed that AGR2 was overexpressed in Chinese Han PCa tissues and had a positive correlation with cyclin D1 and p-Rb but not with p16(INK4a). AGR2 expression profiles varied among cell lines, with PC3 cells being the highest level, LNCaP and DU145 relatively less. The expression of cyclin D1 showed similar pattern to the AGR2 in cell lines. Knockdown of AGR2 caused a decrease in cell viability in PC3 cells, whereas forced expression of AGR2 led to an increased cell proliferation of LNCaP and DU145 cells. Importantly, AGR2 depletion resulted in accumulation of cells at the G(0)/G(1) phase and induction of cellular senescence in all three PCa cell lines as indicated by an increase of flat, enlarged and senescence-associated β-galactosidase (SA-β-Gal) positive cells. Senescent response to AGR2 silencing was also evidenced by elevated γH2AX and fluorescent punctuate formation of tri-methyl-histone H3 in AGR2-depleted cells. Further studies indicated that LNCaP underwent a p21(CIP1)-dependent cellular senescence in response to AGR2 depletion that requires inactivation of ERK signaling, whereas PC-3 was also p21(CIP1) dependent but involved in suppression of PI3K/Akt. Unlike LNCaP and PC-3, senescent response of DU145 was found to be mainly p27(KIP1) dependent that may require upregulation of PTEN and inhibition of PI3K/Akt signaling. Thus, these findings suggest a novel role of AGR2 in regulation of cellular senescence.

Clinical significance of annexin A1 expression in breast cancer

PURPOSE

The expression of Annexin A1 (ANXA1) is known to be reduced in human breast cancer; however, the role of ANXA1 expression in the development of breast cancer remains unclear. In this study, we determined the relationship between the expression features of ANXA1 and the prognostic factors of breast cancer.

METHODS

Human breast tissues were obtained from patients specimens who had undergone breast surgery or core needle biopsies. The patterns of ANXA1 expression were analyzed by immunohistochemical staining in relation to histopathological diagnosis, clinical characteristics and outcomes.

RESULTS

One hundred eighty-two cases were included and the mean age of the patients was 46.34 ± 11.5 years. A significant loss of ANXA1 expression was noted in both ductal carcinoma in situ (DCIS) and invasive carcinomas compared to normal breast tissues (p<0.001) and benign breast diseases (p<0.001). There was a significant alteration in ANXA1 expression according to hormone receptor status (p<0.001), cancer intrinsic type (p<0.001), and nuclear grade (p=0.004) in invasive cancer. In a univariate analysis, ANXA1 positivity tended to be related with poor breast cancer-related survival (p=0.062); however, the same results was not realized in multivariate results (p=0.406). HER2 overexpression and TNM staging were significantly associated with relapse-free survivals (RFS) in the multivariate analysis (p=0.037, p=0.048, respectively). In particular, in node-positive patients (p=0.048), HER2 overexpressed patients (p=0.013), and non-triple negative breast cancer patients (p=0.002), ANXA1 overexpression was correlated with poor RFS.

CONCLUSION

Although significant loss of ANXA1 expression was noted in breast cancer including DCIS and invasive carcinoma, in cases of invasive cancer, overexpression of ANXA1 was related to unfavorable prognostic factors. And these results imply that ANXA1 plays dualistic roles and is involved in variable mechanisms related to cancer development and progression.

Higher levels of GATA3 predict better survival in women with breast cancer

The GATA family members are zinc finger transcription factors involved in cell differentiation and proliferation. GATA3 in particular is necessary for mammary gland maturation, and its loss has been implicated in breast cancer development. Our goal was to validate the ability of GATA3 expression to predict survival in breast cancer patients. Protein expression of GATA3 was analyzed on a high-density tissue microarray consisting of 242 cases of breast cancer. We associated GATA3 expression with patient outcomes and clinicopathologic variables. Expression of GATA3 was significantly increased in breast cancer, in situ lesions, and hyperplastic tissue compared with normal breast tissue. GATA3 expression decreased with increasing tumor grade. Low GATA3 expression was a significant predictor of disease-related death in all patients, as well as in subgroups of estrogen receptor-positive or low-grade patients. In addition, low GATA3 expression correlated with increased tumor size and estrogen and progesterone receptor negativity. GATA3 is an important predictor of disease outcome in breast cancer patients. This finding has been validated in a diverse set of populations. Thus, GATA3 expression has utility as a prognostic indicator in breast cancer.

Differential expression of anterior gradient gene AGR2 in prostate cancer

Background

The protein AGR2 is a putative member of the protein disulfide isomerase family and was first identified as a homolog of the Xenopus laevis gene XAG-2. AGR2 has been implicated in a number of human cancers. In particular, AGR2 has previously been found to be one of several genes that encode secreted proteins showing increased expression in prostate cancer cells compared to normal prostatic epithelium.

Methods

Gene expression levels of AGR2 were examined in prostate cancer cells by microarray analysis. We further examined the relationship of AGR2 protein expression to histopathology and prostate cancer outcome on a population basis using tissue microarray technology.

Results

At the RNA and protein level, there was an increase in AGR2 expression in adenocarcinoma of the prostate compared to morphologically normal prostatic glandular epithelium. Using a tissue microarray, this enhanced AGR2 expression was seen as early as premalignant PIN lesions. Interestingly, within adenocarcinoma samples, there was a slight trend toward lower levels of AGR2 with increasing Gleason score. Consistent with this, relatively lower levels of AGR2 were highly predictive of disease recurrence in patients who had originally presented with high-stage primary prostate cancer (P = 0.009).

Conclusions

We have shown for the first time that despite an increase in AGR2 expression in prostate cancer compared to non-malignant cells, relatively lower levels of AGR2 are highly predictive of disease recurrence following radical prostatectomy.

Epithelial membrane protein-2 is a novel therapeutic target in ovarian cancer

PURPOSE

The tetraspan protein epithelial membrane protein-2 (EMP2) has been shown to regulate the surface display and signaling from select integrin pairs, and it was recently identified as a prognostic biomarker in human endometrial cancer. In this study, we assessed the role of EMP2 in human ovarian cancer.

EXPERIMENTAL DESIGN

We examined the expression of EMP2 within a population of women with ovarian cancer using tissue microarray assay technology. We evaluated the efficacy of EMP2-directed antibody therapy using a fully human recombinant bivalent antibody fragment (diabody) in vitro and ovarian cancer xenograft models in vivo.

RESULTS

EMP2 was found to be highly expressed in >70% of serous and endometrioid ovarian tumors compared with nonmalignant ovarian epithelium using a human ovarian cancer tissue microarray. Using anti-EMP2 diabody, we evaluated the in vitro response of nine human ovarian cancer cell lines with detectable EMP2 expression. Treatment of human ovarian cancer cell lines with anti-EMP2 diabodies induced cell death and retarded cell growth, and these response rates correlated with cellular EMP2 expression. We next assessed the effects of anti-EMP2 diabodies in mice bearing xenografts from the ovarian endometrioid carcinoma cell line OVCAR5. Anti-EMP2 diabodies significantly suppressed tumor growth and induced cell death in OVCAR5 xenografts.

CONCLUSIONS

These findings indicate that EMP2 is expressed in the majority of ovarian tumors and may be a feasible target in vivo.

Anterior gradient-2 plays a critical role in breast cancer cell growth and survival by modulating cyclin D1, estrogen receptor-alpha and survivin

Introduction

Anterior-gradient 2 (AGR2) is an estrogen-responsive secreted protein. Its upregulation has been well documented in a number of cancers, particularly breast cancer, for which mixed data exist on the prognostic implications of AGR2 expression. Although emerging evidence indicates that AGR2 is associated with poor prognosis, its function and impact on cancer-relevant pathways have not been elucidated in breast cancer.

Methods

To investigate the biologic role of AGR2 in breast cancer, AGR2 was transiently knocked down, by using siRNA, in T47 D and ZR-75-1 (estrogen receptor-α (ER)-positive) and MDA-MB-231 and SK-BR-3 (ER-negative) human breast cancer cell lines. The impact of silencing AGR2 was evaluated in both anchorage-dependent and anchorage-independent growth (soft agar, spheroid) assays. Cell-cycle profiles in ER-positive cell lines were determined with BrdU incorporation, and cell death was measured with Annexin V, JC-1, and F7-26 staining. After transiently silencing AGR2 or stimulating with recombinant AGR2, modulation of key regulators of growth and survival pathways was assessed with Western blot. Combination studies of AGR2 knockdown with the antiestrogens tamoxifen and fulvestrant were carried out and assessed at the level of anchorage-dependent growth inhibition and target modulation (cyclin D1, ER).

Results

AGR2 knockdown inhibited growth in anchorage-dependent and anchorage-independent assays, with a more-pronounced effect in ER-positive cell lines. Cyclin D1 levels and BrdU incorporation were reduced with AGR2 knockdown. Conversely, cyclin D1 was induced with recombinant AGR2. AGR2 knockdown induced cell death in ZR-75-1 and T47 D cells, and also downregulated survivin and c-Myc. Evidence of AGR2-ER crosstalk was demonstrated by a reduction of ER at the protein level after transiently silencing AGR2. AGR2 knockdown in combination with fulvestrant or tamoxifen did not preclude the efficacy of the antiestrogens, but enhanced it. In addition, p-Src, implicated in tamoxifen resistance, was downregulated with AGR2 knockdown.

Conclusions

Transiently silencing AGR2 in ER-positive breast cancer cell lines inhibited cell growth and cell-cycle progression and induced cell death. Breast cancer drivers (ER and cyclin D1) as well as cancer-signaling nodes (pSrc, c-Myc, and survivin) were demonstrated to be downstream of AGR2. Collectively, the data presented support the utility of anti-AGR2 therapy in ER-positive breast cancers because of its impact on cancer-relevant pathways.

Novel proteins regulated by mTOR in subependymal giant cell astrocytomas of patients with tuberous sclerosis complex and new therapeutic implications

Subependymal giant cell astrocytomas (SEGAs) are rare brain tumors associated with tuberous sclerosis complex (TSC), a disease caused by mutations in TSC1 or TSC2, resulting in enhancement of mammalian target of rapamycin (mTOR) activity, dysregulation of cell growth, and tumorigenesis. Signaling via mTOR plays a role in multifaceted genomic responses, but its effectors in the brain are largely unknown. Therefore, gene expression profiling on four SEGAs was performed with Affymetrix Human Genome arrays. Of the genes differentially expressed in TSC, 11 were validated by real-time PCR on independent tumor samples and 3 SEGA-derived cultures. Expression of several proteins was confirmed by immunohistochemistry. The differentially-regulated proteins were mainly involved in tumorigenesis and nervous system development. ANXA1, GPNMB, LTF, RND3, S100A11, SFRP4, and NPTX1 genes were likely to be mTOR effector genes in SEGA, as their expression was modulated by an mTOR inhibitor, rapamycin, in SEGA-derived cells. Inhibition of mTOR signaling affected size of cultured SEGA cells but had no influence on their proliferation, morphology, or migration, whereas inhibition of both mTOR and extracellular signal-regulated kinase signaling pathways led to significant alterations of these processes. For the first time, we identified genes related to the occurrence of SEGA and regulated by mTOR and demonstrated an effective modulation of SEGA growth by pharmacological inhibition of both mTOR and extracellular signal-regulated kinase signaling pathways, which could represent a novel therapeutic approach.

The RNA-binding protein HuR regulates GATA3 mRNA stability in human breast cancer cell lines

Meta-analyses of microarray data indicate that GATA3 is co-expressed with estrogen receptor alpha (ER) in breast cancer cells. While the significance of this remains unclear, it is thought that GATA3 may serve as a prognostic indicator in breast tumors and may play a role in ER signaling. Recently, reciprocal regulation of GATA3 and ER transcription was demonstrated, suggesting that control of their expression is intertwined. We sought to determine whether GATA3 and ER expression was also coordinately regulated at other levels. Unlike ER, GATA3 was not under epigenetic control and was not re-expressed in the presence of DNMT or HDAC inhibitors in ER/GATA3-negative cells. However, like ER, these inhibitors decreased GATA3 expression in ER/GATA3-positive cell lines. We have previously reported that ER mRNA stability is increased through binding of the RNA-binding protein HuR/ELAV1 to the 3'untranslated region (UTR) and that DNMT and HDAC inhibitors reduce ER expression by altering this interaction. Biotin pull-down assays using a biotinylated GATA3 RNA probe confirmed that HuR also binds to the GATA3 3'UTR. Inhibition of HuR using siRNA probes decreased GATA3 mRNA, mRNA stability and protein expression, indicating that HuR plays a role in regulating GATA3 expression. Inhibition of either HuR or GATA3 reduced cell growth of MCF7 cells. Based on our findings, it is clear that coordinate regulation of ER and GATA3 occurs, however differences do exist. These findings may aid in identification of new targets that control cell growth of breast cancer cells.

Effects of green tea extract on lung cancer A549 cells: proteomic identification of proteins associated with cell migration

Green tea polyphenols exhibit multiple antitumor activities, and the mechanisms of action are not completely understood. Previously, we reported that green tea extract (GTE)-induced actin remolding is associated with increased cell adhesion and decreased motility in A549 lung cancer cells. To identify the cellular targets responsible for green tea-induced actin remodeling, we performed 2-DE LC-MS/MS of A549 cells before and after GTE exposure. We have identified 14 protein spots that changed in expression (> or =2-fold) after GTE treatment. These proteins are involved in calcium-binding, cytoskeleton and motility, metabolism, detoxification, or gene regulation. In particular we found upregulation of several genes that modulate actin remodeling and cell migration, including lamin A/C. Our data indicated that GTE-induced lamin A/C upregulation appears to be at the transcriptional level and the increased expression results in the decrease in cell motility, as confirmed by siRNA. The result of the study demonstrates that GTE alters the levels of many proteins involved in growth, motility and apoptosis of A549 cells and their identification may explain the multiple antitumor activities of GTE.

Decreased expression of Annexin A1 correlates with pathologic differentiation grade in oral squamous cell carcinoma

Previously, we established an in vitro cellular carcinogenesis model of oral squamous cell carcinoma (OSCC), including the human immortalized oral epithelia cells (HIOECs) and its derived cancerous HB96 cells. In this study, comparative proteomic analysis identified that Annexin A1 was one of the significantly down-regulated genes in the cancerous HB96 cells. To investigate Annexin A1 down-regulation and its potential usefulness as a molecular marker in OSCC, we further screened Annexin A1 expressions with a panel of OSCC lines, and clinical samples of cancerous and the paired adjacent normal tissues from primary OSCC patients. By Western blot analysis and real-time PCR, we showed that both Annexin A1 mRNA and protein expressions decreased in OSCC cell lines except in two cell lines for the mRNA levels. Immunohistochemistry and real-time PCR also showed that both Annexin A1 mRNA and protein expressions decreased in the cancerous tissues from OSCC patients compared with those in the paired adjacent non-malignant epithelia. More importantly, both Annexin A1 mRNA and protein expressions negatively correlated with the pathologic differentiation grades of cancerous tissues. The lower Annexin A1 mRNA or protein expressions correlated with the poorer pathologic differentiation grades. These results suggest that decreased expression of Annexin A1 contributes to the cancerous progression of OSCC, and Annexin A1 may be a potential biomarker for pathologic differentiation grade of OSCC.

Characterisation of tumoral markers correlated with ErbB2 (HER2/Neu) overexpression and metastasis in breast cancer

The receptor tyrosine kinase ErbB2 (HER2/neu) is overexpressed in ˜30% of breast cancers and is associated with poor prognosis and an increased likelihood of metastasis. Clinical treatments such as trastuzumab are effective in less than 35% of women diagnosed as ErbB2-positive, highlighting the necessity of searching for novel targets and alternative therapies. Herein, a proteomic screening strategy combining quantitative-based gel electrophoresis and MS was used to compare the protein expression of 48 normal human breast and tumour tissues differing in ErbB2 expression and lymph node status. The aim was to identify proteins associated with the aggressive phenotype of ErbB2-positive breast cancer which could be potential biomarkers of the disease as well as therapy targets. In total, 177 protein isoforms (107 gene products) differentially expressed between tissue groups were identified. Immunohistochemical staining of a tissue-microarray was used for validation of selected protein candidates. We found that expression of HSP90α, laminin and GSTP1 significantly correlated with ErbB2 expression, while others such as AGR2, NM23H1 and Annexin 2 were overexpressed in greater than 40% of tumours. Finally, knocking-down the expression by RNA interference of three candidates, AGR2, Transgelin2 and NM23H1 resulted in an enhanced invasive capacity of MDA-MB435 cells. These data support the involvement of these targets in tumour progression and identify them as novel biomarkers of the disease.

Tissue microarray analysis reveals strong clinical evidence for a close association between loss of annexin A1 expression and nodal metastasis in gastric cancer

AIMS

Annexin A1 (ANXA1) is a calcium- and phospholipid-binding protein that has been implicated in the regulation of inflammation, cell proliferation, and apoptosis. Its role in tumor development and progression is controversial, whereas its role in gastric cancer is unknown. We investigated ANXA1 expression and determined its clinical significance in gastric cancer.

METHODS AND RESULTS

Tissue microarray blocks containing primary gastric cancer, lymph node metastasis, and adjacent normal mucosa specimens obtained from 1,072 Chinese patients were constructed. Expression of ANXA1 in these specimens was analyzed using immunohistochemistry. Complete loss of ANXA1 expression was observed in 691 (64%) of the 1,072 primary tumors and 146 (86%) of 169 nodal metastases. Loss of ANXA1 expression was significantly associated with advanced T stage, lymph node metastasis, advanced disease stage, and poor histological differentiation. Loss of ANXA1 expression correlated significantly with poor survival rates in both univariate and multivariate analyses.

CONCLUSIONS

ANXA1 expression decreased significantly as gastric cancer progressed and metastasized, suggesting the importance of ANXA1 as a negative biomarker for gastric cancer development and progression.

Novel breast cancer biomarkers identified by integrative proteomic and gene expression mapping

Proteomic and transcriptomic platforms both play important roles in cancer research, with differing strengths and limitations. Here, we describe a proteo-transcriptomic integrative strategy for discovering novel cancer biomarkers, combining the direct visualization of differentially expressed proteins with the high-throughput scale of gene expression profiling. Using breast cancer as a case example, we generated comprehensive two-dimensional electrophoresis (2DE)/mass spectrometry (MS) proteomic maps of cancer (MCF-7 and HCC-38) and control (CCD-1059Sk) cell lines, identifying 1724 expressed protein spots representing 484 different protein species. The differentially expressed cell-line proteins were then mapped to mRNA transcript databases of cancer cell lines and primary breast tumors to identify candidate biomarkers that were concordantly expressed at the gene expression level. Of the top nine selected biomarker candidates, we reidentified ANX1, a protein previously reported to be differentially expressed in breast cancers and normal tissues, and validated three other novel candidates, CRAB, 6PGL, and CAZ2, as differentially expressed proteins by immunohistochemistry on breast tissue microarrays. In total, close to half (4/9) of our protein biomarker candidates were successfully validated. Our study thus illustrates how the systematic integration of proteomic and transcriptomic data from both cell line and primary tissue samples can prove advantageous for accelerating cancer biomarker discovery.

Annexinopathies

Annexins comprise a conserved family of proteins characterised by their ability to bind and order charged phospholipids in membranes, often in response to elevated intracellular calcium. The family members (there are at least 12 in humans) have become specialised over evolutionary time and are involved in a diverse range of cellular functions both inside the cell and extracellularly Although a mutation in an annexin has never been categorically proven to be the cause of a disease state, they have been implicated in pathologies as diverse as autoimmunity, infection, heart disease, diabetes and cancer. 'Annexinopathies' were first described by Jacob H. Rand to describe the pathological sequelae in two disease states, the overexpression of annexin 2 in a patients with a haemorrhagic form of acute promyelocytic leukaemia, and the under-expression of annexin 5 on placental trophoblasts in the antiphospholipid syndrome. In this chapter we will outline some of the more recent observations in regard to these conditions, and describe the involvement of annexins in some other major causes of human morbidity.

In silico gene expression analysis--an overview

Efforts aimed at deciphering the molecular basis of complex disease are underpinned by the availability of high throughput strategies for the identification of biomolecules that drive the disease process. The completion of the human genome-sequencing project, coupled to major technological developments, has afforded investigators myriad opportunities for multidimensional analysis of biological systems. Nowhere has this research explosion been more evident than in the field of transcriptomics. Affordable access and availability to the technology that supports such investigations has led to a significant increase in the amount of data generated. As most biological distinctions are now observed at a genomic level, a large amount of expression information is now openly available via public databases. Furthermore, numerous computational based methods have been developed to harness the power of these data. In this review we provide a brief overview of in silico methodologies for the analysis of differential gene expression such as Serial Analysis of Gene Expression and Digital Differential Display. The performance of these strategies, at both an operational and result/output level is assessed and compared. The key considerations that must be made when completing an in silico expression analysis are also presented as a roadmap to facilitate biologists. Furthermore, to highlight the importance of these in silico methodologies in contemporary biomedical research, examples of current studies using these approaches are discussed. The overriding goal of this review is to present the scientific community with a critical overview of these strategies, so that they can be effectively added to the tool box of biomedical researchers focused on identifying the molecular mechanisms of disease.

TPD52 and NFKB1 gene expression levels correlate with G2 chromosomal radiosensitivity in lymphocytes of women with and at risk of hereditary breast cancer

PURPOSE

To evaluate a transcriptomic approach to identify healthy women at increased risk of breast cancer due to G2-radiosensitivity and look at transcripts that are differentially expressed between individuals.

MATERIALS AND METHODS

We perform the first study to assess the association of G2 radiosensitivity with basal gene expression in cultured T-lymphocytes from 11 women with breast cancer and 12 healthy female relatives using Affymetrix GeneChips.

RESULTS

Transcripts associated with radiosensitivity and breast cancer risk were predominantly involved in innate immunity and inflammation, such as interleukins and chemokines. Genes differentially expressed in radiosensitive individuals were more similarly expressed in close family members than in un-related individuals, suggesting heritability of the trait. The expression of tumour protein D52 (TPD52), a gene implicated in cell proliferation, apoptosis, and vesicle trafficking was the most strongly correlated with G2 score while nuclear factor (kappa)-B (NFKB1) was highly inversely correlated with G2 score. NFKB1 is known to be activated by irradiation and its inhibition has been previously shown to increase radiosensitivity.

CONCLUSIONS

Gene expression analysis of lymphocytes may provide a quantitative measure of radiation response potential and is a promising marker of breast cancer susceptibility.

Mitochondrial alterations in human gastric carcinoma cell line

We compared mitochondrial function, morphology, and proteome in the rat normal gastric cell line RGM-1 and the human gastric cancer cell line AGS. Total numbers and cross-sectional sizes of mitochondria were smaller in AGS cells. Mitochondria in AGS cells were deformed and consumed less oxygen. Confocal microscopy indicated that the mitochondrial inner membrane potential was hyperpolarized and the mitochondrial Ca(2+) concentration was elevated in AGS cells. Interestingly, two-dimensional electrophoresis proteomics on the mitochondria-enriched fraction revealed high expression of four mitochondrial proteins in AGS cells: ubiquinol-cytochrome c reductase, mitochondrial short-chain enoyl-coenzyme A hydratase-1, heat shock protein 60, and mitochondria elongation factor Tu. The results provide clues as to the mechanism of the mitochondrial changes in cancer at the protein level and may serve as potential cancer biomarkers in mitochondria.

Transplacental exposure to inorganic arsenic at a hepatocarcinogenic dose induces fetal gene expression changes in mice indicative of aberrant estrogen signaling and disrupted steroid metabolism

Exposure to inorganic arsenic in utero in C3H mice produces hepatocellular carcinoma in male offspring when they reach adulthood. To help define the molecular events associated with the fetal onset of arsenic hepatocarcinogenesis, pregnant C3H mice were given drinking water containing 0 (control) or 85 ppm arsenic from day 8 to 18 of gestation. At the end of the arsenic exposure period, male fetal livers were removed and RNA isolated for microarray analysis using 22K oligo chips. Arsenic exposure in utero produced significant (p<0.001) alterations in expression of 187 genes, with approximately 25% of aberrantly expressed genes related to either estrogen signaling or steroid metabolism. Real-time RT-PCR on selected genes confirmed these changes. Various genes controlled by estrogen, including X-inactive-specific transcript, anterior gradient-2, trefoil factor-1, CRP-ductin, ghrelin, and small proline-rich protein-2A, were dramatically over-expressed. Estrogen-regulated genes including cytokeratin 1-19 and Cyp2a4 were over-expressed, although Cyp3a25 was suppressed. Several genes involved with steroid metabolism also showed remarkable expression changes, including increased expression of 17beta-hydroxysteroid dehydrogenase-7 (HSD17beta7; involved in estradiol production) and decreased expression of HSD17beta5 (involved in testosterone production). The expression of key genes important in methionine metabolism, such as methionine adenosyltransferase-1a, betaine-homocysteine methyltransferase and thioether S-methyltransferase, were suppressed. Thus, exposure of mouse fetus to inorganic arsenic during a critical period in development significantly alters the expression of various genes encoding estrogen signaling and steroid or methionine metabolism. These alterations could disrupt genetic programming at the very early life stage, which could impact tumor formation much later in adulthood.

Fog2 excision in mice leads to premature mammary gland involution and reduced Esr1 gene expression

The critical role for GATA family proteins in maintaining the normal (non-transformed) cell state is corroborated by the recent findings of mutations or methylation in GATA genes both in primary cancers and tumor lines including breast. Previously, microarray profiling studies determined that the highest expression of both GATA3 and ESR1 (estrogen receptor alpha) is seen in tumors associated with the most favorable survival outcomes, whereas the lowest expression of GATA3 is detected in tumor subtypes showing the worst outcomes. At this time, genes and pathways that are regulated by GATA3 in the mammary gland are not well defined. We have previously established a requirement for FOG (Friend Of GATA) cofactors during mouse development. Here we report that in the murine mammary gland Fog2 gene expression is upregulated upon pregnancy and lactation with prominent expression in the epithelial cells of the gland during post-lactational regression. Mammary-specific deletion of Fog2 identified a role for this gene during gland involution; excision of the Fog2 gene leads to the accelerated involution of the gland despite diminished levels of the remodeling enzymes. Importantly, the levels of several genes linked to the control of cancerous transformation in the breast (Esr1, Prg and Foxa1) are significantly reduced upon Fog2 excision. This implicates FOG2 in the maintenance of epithelial cell differentiation in the mammary gland and in performing a protective role in breast cancer.