Novel gene C17orf37 in 17q12 amplicon promotes migration and invasion of prostate cancer cells

Epigenetics as a Key Factor in Prostate Cancer

Nowadays, prostate cancer is one of the most common forms of malignant neoplasms in men all over the world. Against the background of increasing incidence, there is a high mortality rate from prostate cancer, which is associated with an inadequate treatment strategy. Such a high prevalence of prostate cancer requires the development of methods that can ensure early detection of the disease, improve the effectiveness of treatment, and predict the therapeutic effect. Under these circumstances, it becomes crucial to focus on the development of effective diagnostic and therapeutic approaches. Due to the development of molecular genetic methods, a large number of studies have been accumulated on the role of epigenetic regulation of gene activity in cancer development, since it is epigenetic changes that can be detected at the earliest stages of cancer development. The presence of epigenetic aberrations in tumor tissue and correlations with drug resistance suggest new therapeutic approaches. Detection of epigenetic alterations such as CpG island methylation, histone modification, and microRNAs as biomarkers will improve the diagnosis of the disease, and the use of these strategies as targets for therapy will allow for greater personalization of prostate cancer treatment.

Short peptides based on the conserved regions of MIEN1 protein exhibit anticancer activity by targeting the MIEN1 signaling pathway

Migration and invasion enhancer 1 (MIEN1) overexpression characterizes several cancers and facilitates cancer cell migration and invasion. Leveraging conserved immunoreceptor tyrosine-based activation motif and prenylation motifs within MIEN1, we identified potent anticancer peptides. Among them, bioactive peptides LA3IK and RP-7 induced pronounced transcriptomic and protein expression changes at sub-IC50 concentrations. The peptides effectively inhibited genes and proteins driving cancer cell migration, invasion, and epithelial-mesenchymal transition pathways, concurrently suppressing epidermal growth factor-induced nuclear factor kappa B nuclear translocation in metastatic breast cancer cells. Specifically, peptides targeted the same signal transduction pathway initiated by MIEN1. Molecular docking and CD spectra indicated the formation of MIEN1-peptide complexes. The third-positioned isoleucine in LA3IK and CVIL motif in RP-7 were crucial for inhibiting breast cancer cell migration. This is evident from the limited migration inhibition observed when MDA-MB-231 cells were treated with scrambled peptides LA3IK SCR and RP-7 SCR. Additionally, LA3IK and RP-7 effectively suppressed tumor growth in an orthotopic breast cancer model. Notably, mice tolerated high intraperitoneal (ip) peptide doses of 90 mg/Kg well, surpassing significantly lower doses of 5 mg/Kg intravenously (iv) and 30 mg/Kg intraperitoneally (ip) used in both in vivo pharmacokinetic studies and orthotopic mouse model assays. D-isomers of LA3IK and RP-7 showed enhanced anticancer activity compared to their L-isomers. D-LA3IK remained stable in mouse plasma for 24 h with 75% remaining, exhibiting superior pharmacokinetic properties over D/L-RP-7. In summary, our findings mark the first report of short peptides based on MIEN1 protein sequence capable of inhibiting cancer signaling pathways, effectively impeding cancer progression both in vitro and in vivo.

CRISPR-based therapeutic targeting of signaling pathways in breast cancer

Breast cancer remains a leading cause of death for women worldwide, and new treatment strategies are needed. There are innumerable anomalous genes that are responsible for the multi-factorial carcinogenesis pathway. Although several disease-causing mutations have been detected, therapy frequently focuses on attenuating the manifestation of the disease rather than harmonizing the mutation in the target area. The advent of CRISPR-Cas9 technology has revolutionized genome editing, allowing for precise and efficient manipulation of gene expression. The purpose of this review paper is to summarize recent progress in the use of CRISPR-based approaches to target key signaling pathways associated with breast cancer progression. The first section introduces basic concepts of CRISPR technology, focusing on its application in genome editing and transcriptional regulation followed by an overview of aspects involving complex signaling pathways in breast cancer such as P13K/AKT/mTOR, EPK/MAPK and Wnt/β catenin. An extensive literature search using PubMed and Google Scholar is performed for information retrieval. Further, the role of CRISPR-based interventions in regulating gene expression revealed, altered pathway activity and potential therapeutic consequences are discussed. This review will be a valuable addition to providing comprehensive knowledge of CRISPR-Cas-mediated therapeutic targeting in breast cancer.

Molecular characteristics of gastric cancer with ERBB2 amplification

Gastric cancer is a prevalent malignancy with a high degree of heterogeneity, which has led to a poor therapeutic response. Though there are numerous HER2-targeted medicines for HER2+ gastric cancer, many trials have not indicated an improvement in overall survival. Here 29 ERBB2 amplification (ERBB2-Amp) type gastric cancer samples with WES and RNA-seq data were selected for investigation, which copy-number aberration (CNA) was +2. Initially, the somatic mutation and copy number variant (CNV) of them, which might cause resistance to HER2-targeted therapies, were systematically investigated evaluated, as well as their mutation signatures. Moreover, 37 modules were identified using weighted gene co-expression network analysis (WGCNA), including the blue module related to DFS status and lightcyan module correlated with ARHGAP26_ARHGAP6_CLDN18 rearrangement. In addition, focal adhesion and ECM-receptor interaction pathways were considerably enriched in the turquoise module with ERBB2 gene. ExportNetworkToCytoscape determined that MIEN1 and GRB7 are tightly connected to ERBB2., Finally, 14 single-cell intestinal gastric cancer samples were investigated, and it was shown that the TFAP2A transcription factor regulon was highly expressed in ERBB2high group, as was the EMT score. Overall, our data provide comprehensive molecular characteristics of ERBB2-Amp type gastric cancer, which offers additional information to improve HER2-targeted gastric cancer treatment.

Structure and Functions of HMGB2 Protein

High-Mobility Group (HMG) chromosomal proteins are the most numerous nuclear non-histone proteins. HMGB domain proteins are the most abundant and well-studied HMG proteins. They are involved in variety of biological processes. HMGB1 and HMGB2 were the first members of HMGB-family to be discovered and are found in all studied eukaryotes. Despite the high degree of homology, HMGB1 and HMGB2 proteins differ from each other both in structure and functions. In contrast to HMGB2, there is a large pool of works devoted to the HMGB1 protein whose structure-function properties have been described in detail in our previous review in 2020. In this review, we attempted to bring together diverse data about the structure and functions of the HMGB2 protein. The review also describes post-translational modifications of the HMGB2 protein and its role in the development of a number of diseases. Particular attention is paid to its interaction with various targets, including DNA and protein partners. The influence of the level of HMGB2 expression on various processes associated with cell differentiation and aging and its ability to mediate the differentiation of embryonic and adult stem cells are also discussed.

HRD1 Promotes Non-small Cell Lung Carcinoma Metastasis by Blocking Autophagy-mediated MIEN1 Degradation

Dysregulation of autophagy has been implicated in the development of many diseases, including cancer. Here, we revealed a novel function of the E3 ubiquitin ligase HRD1 in non-small cell lung carcinoma (NSCLC) metastasis by regulating autophagy. Mechanistically, HRD1 inhibits autophagy by promoting ATG3 ubiquitination and degradation. Additionally, a pro-migratory and invasive factor, MIEN1 (migration and invasion enhancer 1), was found to be autophagically degraded upon HRD1 deficiency. Importantly, both HRD1 and MIEN1 expression are upregulated and positively correlated in lung tumors. Based on these results, we proposed a novel mechanism of HRD1 function that the degradation of ATG3 protein by HRD1 leads to autophagy inhibition and MIEN1 release, thus promoting NSCLC metastasis. Therefore, our findings provided new insights into the role of HRD1 in NSCLC metastasis and new therapeutic targets for lung cancer treatment.

Recent advances in biosensor devices for HER-2 cancer biomarker detection

The human epidermal growth factor receptor 2 (HER-2) protein is a member of the epidermal growth factor receptor (EGFR or ErbB) family and is a transmembrane tyrosine kinase receptor. HER-2 is highly regulated in ovarian, lung, gastric, oral, and breast cancers. The low specificity, complexity, expensiveness and the lack of sensitivity are essential restrictions in traditional diagnosis methods such as FISH, immunohistochemistry and PCR and these disadvantages led to the need for more studies on alternative methods. Biosensor technology has greatly affected the quality of human life owing to its features including, sensitivity, specificity, and rapid diagnosis and monitoring of different patient diseases. In this review article, we examine various biosensors, considering that they have been categorized based on the transducers used including piezoelectric biosensors, optical sensors such as fluorescence and surface plasmon resonance, and electrochemical types for the diagnosis of HER-2 and the effectiveness of some drugs against that. Attention to developing some types of biosensor devices such as colorimetric biosensors for HER-2 detection can be an important point in future studies.

New Insights into the Therapeutic Applications of CRISPR/Cas9 Genome Editing in Breast Cancer

Breast cancer is one of the most prevalent forms of cancer globally and is among the leading causes of death in women. Its heterogenic nature is a result of the involvement of numerous aberrant genes that contribute to the multi-step pathway of tumorigenesis. Despite the fact that several disease-causing mutations have been identified, therapy is often aimed at alleviating symptoms rather than rectifying the mutation in the DNA sequence. The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 is a groundbreaking tool that is being utilized for the identification and validation of genomic targets bearing tumorigenic potential. CRISPR/Cas9 supersedes its gene-editing predecessors through its unparalleled simplicity, efficiency and affordability. In this review, we provide an overview of the CRISPR/Cas9 mechanism and discuss genes that were edited using this system for the treatment of breast cancer. In addition, we shed light on the delivery methods—both viral and non-viral—that may be used to deliver the system and the barriers associated with each. Overall, the present review provides new insights into the potential therapeutic applications of CRISPR/Cas9 for the advancement of breast cancer treatment.

MiR-124-5p Inhibits the Progression of Gastric Cancer by Targeting MIEN1

Objective:

To observe the effect of miR-124-5p on progression of gastric cancer (GC) and explore the targeting mechanism.

Methods:

After collecting the specimens, we used real-time fluorescence quantitative PCR to detect the miR-124-5p level of GC tissue and corresponding adjacent tissue. Then MTT test and scratch wound-healing assay were hired to evaluate the influence of miR-124-5p in GC cell (SGC-803 and SGC7901) migration and proliferation ability. The binding of miR-124-5p to migration and invasion enhancer 1 (MIEN1) was detected through dual luciferase reporter gene experiment and western blot was utilized to assay the protein level of MIEN1.

Results:

Compared with adjacent tissues, miR-124-5p level in GC tissues was lower significantly. MiR-124-5p mimic inhibited the metastasis and proliferation ability of SGC7901 cells and miR-124-5p inhibitor promoted the migration and proliferation ability of SGC803 cells. In addition, miR-124-5p targeted MIEN1 and negatively modulated the MIEN1 expression in SGC-803 and SGC7901 cells. Silencing MIEN1 negatively regulated the metastasis and proliferation ability of SGC7901 cells.

Conclusion:

MiR-124-5p inhibited the GC cell proliferation and metastasis phenotypes through MIEN1, which probably becomes a novel molecular target for clinical GC treatment.

Evaluating Trastuzumab in the treatment of HER2 positive breast cancer

The transmembrane oncoprotein HER2 is encoded by ERBB2 gene and overexpressed in around 20% of invasive breast cancers. It can be specifically targeted by Trastuzumab (Herceptin®), a humanised IgG1 antibody. Trastuzumab has been regarded as one of the most effective therapeutic drugs targeted to HER2 positive cancers. However, there are drawbacks, notably cardiotoxicity and resistance, which have raised awareness in clinical use. Therefore, understanding the mechanism of action is vital to establish improved therapeutic strategies. Here we evaluate Trastuzumab application in the treatment of HER2 positive breast cancer, focusing on its mechanistic actions and clinical effectiveness. Alternative therapies targeting the HER2 receptor and its downstream anomalies will also be discussed, as these could highlight further targets that could be key to improving clinical outcomes.

Characterization of HMGB1/2 Interactome in Prostate Cancer by Yeast Two Hybrid Approach: Potential Pathobiological Implications

High mobility group box B (HMGB) proteins are pivotal in the development of cancer. Although the proteomics of prostate cancer (PCa) cells has been reported, the involvement of HMGB proteins and their interactome in PCa is an unexplored field of considerable interest. We describe herein the results of the first HMGB1/HMGB2 interactome approach to PCa. Libraries constructed from the PCa cell line, PC-3, and from patients’ PCa primary tumor have been screened by the yeast 2-hybrid approach (Y2H) using HMGB1 and HMGB2 baits. Functional significance of this PCa HMGB interactome has been validated through expression and prognosis data available on public databases. Copy number alterations (CNA) affecting these newly described HMGB interactome components are more frequent in the most aggressive forms of PCa: those of neuroendocrine origin or castration-resistant PCa. Concordantly, adenocarcinoma PCa samples showing CNA in these genes are also associated with the worse prognosis. These findings open the way to their potential use as discriminatory biomarkers between high and low risk patients. Gene expression of a selected set of these interactome components has been analyzed by qPCR after HMGB1 and HMGB2 silencing. The data show that HMGB1 and HMGB2 control the expression of several of their interactome partners, which might contribute to the orchestrated action of these proteins in PCa

Migration and Invasion Enhancer 1 Is an NF-ĸB-Inducing Gene Enhancing the Cell Proliferation and Invasion Ability of Human Prostate Carcinoma Cells In Vitro and In Vivo

Migration and invasion enhancer 1 (MIEN1) is a membrane-anchored protein and exists in various cancerous tissues. However, the roles of MIEN1 in prostate cancer have not yet been clearly addressed. We determined the expression, biological functions, and regulatory mechanisms of MIEN1 in the prostate. The results of immunohistochemical analysis indicated that MIEN1 was expressed specifically in epithelial cells and significantly higher in adenocarcinoma as compared to in normal tissues. MIEN1 enhanced in vitro cell proliferation, invasion, and in vivo tumorigenesis. Meanwhile, MIEN1 attenuated cisplatin-induced apoptosis in PC-3 cells. Overexpression of NF-ĸB-inducing kinase (NIK) enhanced MIEN1 expression, while overexpression of NF-ĸB inhibitor α (IĸBα) blocked MIEN1 expression in PC-3 cells. In prostate carcinoma cells, MIEN1 provoked Akt phosphorylation; moreover, MIEN1 downregulated N-myc downstream regulated 1 (NDRG1) but upregulated interleukin-6 (IL-6) gene expression. MK2206, an Akt inhibitor, impeded the modulation of MIEN1 on NDRG1 and IL-6 expressions. Our studies suggest that MIEN1 is an NF-ĸB downstream oncogene in the human prostate. Accordingly, the modulation of Akt signaling in the gene expressions of NDRG1 and IL-6 may account for the functions of MIEN1 in cell proliferation, invasion, and tumorigenesis in prostate carcinoma cells.

Emerging Role of Migration and Invasion Enhancer 1 (MIEN1) in Cancer Progression and Metastasis

Tumor metastasis is a sequential event accounting for numerous cancer-related fatalities worldwide. The process of metastasis serially involves invasion, intravasation, extravasation, and tumor growth at the secondary site. Migration and invasion enhancer 1 (MIEN1) is a membrane associated protein overexpressed in various human cancers. Biological activity of MIEN1 is driven by geranylgeranyltransferase-I mediated prenylation at CAAX motif and methylation of the prenylated protein that anchors MIEN1 into the cellular membrane. Post-translationally modified MIEN1 interacts with Syk kinase and Annexin A2 protein; polymerizes G-actin and stabilizes F-actin filament; induces focal adhesion kinase phosphorylation and decrease cofilin phosphorylation implicated in both invasion and metastasis of different cancer types. In the present review, we discuss the structure, function, and involvement of MIEN1 in cancer progression. We also highlight the future prospects of MIEN1 as an emerging molecule and novel target in cancer cell invasion and metastasis.

Emerging targets in cancer drug resistance

Drug resistance is a complex phenomenon that frequently develops as a failure to chemotherapy during cancer treatment. Malignant cells increasingly generate resistance to various chemotherapeutic drugs through distinct mechanisms and pathways. Understanding the molecular mechanisms involved in drug resistance remains an important area of research for identification of precise targets and drug discovery to improve therapeutic outcomes. This review highlights the role of some recent emerging targets and pathways which play critical role in driving drug resistance.

CRISPR deletion of MIEN1 in breast cancer cells

Migration and Invasion Enhancer (MIEN1) is an oncogene which is involved in facilitating motility of cancer cells through actin dynamics and gene expression. Increased MIEN1 expression in many types of tumors leads to disease progression and metastatic propensity. It is unclear precisely how MIEN1 is involved in this process and more studies are required to tease out the mechanisms. Here we show that Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) genome editing effectively produced specific genomic deletions in the MIEN1 gene which led to the abrogation of its expression in breast cancer cells. The single guide RNAs (sgRNAs) mediated targeting of MIEN1 was specific and none of the clones screened for off-target cleavage revealed any insertions or deletions (indels). Additionally, disruption of the MIEN1 gene did not alter the cell morphology, growth, proliferation or survival. Knocking out MIEN1 in these breast cancer cells will allow future studies to determine the exact role MIEN1 plays in breast tumor metastasis, which might lead to production of novel therapeutics to treat this and other cancers.

A comprehensive characterization of cis-acting splicing-associated variants in human cancer

Although many driver mutations are thought to promote carcinogenesis via abnormal splicing, the landscape of splicing-associated variants (SAVs) remains unknown due to the complexity of splicing abnormalities. Here, we developed a statistical framework to systematically identify SAVs disrupting or newly creating splice site motifs and applied it to matched whole-exome and transcriptome sequencing data from 8976 samples across 31 cancer types, generating a catalog of 14,438 SAVs. Such a large collection of SAVs enabled us to characterize their genomic features, underlying mutational processes, and influence on cancer driver genes. In fact, ∼50% of SAVs identified were those disrupting noncanonical splice sites (non-GT-AG dinucleotides), including the third and fifth intronic bases of donor sites, or newly creating splice sites. Mutation signature analysis revealed that tobacco smoking is more strongly associated with SAVs, whereas ultraviolet exposure has less impact. SAVs showed remarkable enrichment of cancer-related genes, and as many as 14.7% of samples harbored at least one SAVs affecting them, particularly in tumor suppressors. In addition to intron retention, whose association with tumor suppressor inactivation has been previously reported, exon skipping and alternative splice site usage caused by SAVs frequently affected tumor suppressors. Finally, we described high-resolution distributions of SAVs along the gene and their splicing outcomes in commonly disrupted genes, including TP53, PIK3R1, GATA3, and CDKN2A, which offers genetic clues for understanding their functional properties. Collectively, our findings delineate a comprehensive portrait of SAVs, novel insights into transcriptional de-regulation in cancer.

Delineating the HMGB1 and HMGB2 interactome in prostate and ovary epithelial cells and its relationship with cancer

High Mobility Group B (HMGB) proteins are involved in cancer progression and in cellular responses to platinum compounds used in the chemotherapy of prostate and ovary cancer. Here we use affinity purification coupled to mass spectrometry (MS) and yeast two-hybrid (Y2H) screening to carry out an exhaustive study of HMGB1 and HMGB2 protein interactions in the context of prostate and ovary epithelia. We present a proteomic study of HMGB1 partners based on immunoprecipitation of HMGB1 from a non-cancerous prostate epithelial cell line. In addition, HMGB1 and HMGB2 were used as baits in yeast two-hybrid screening of libraries from prostate and ovary epithelial cell lines as well as from healthy ovary tissue. HMGB1 interacts with many nuclear proteins that control gene expression, but also with proteins that form part of the cytoskeleton, cell-adhesion structures and others involved in intracellular protein translocation, cellular migration, secretion, apoptosis and cell survival. HMGB2 interacts with proteins involved in apoptosis, cell motility and cellular proliferation. High confidence interactors, based on repeated identification in different cell types or in both MS and Y2H approaches, are discussed in relation to cancer. This study represents a useful resource for detailed investigation of the role of HMGB1 in cancer of epithelial origins, as well as potential alternative avenues of therapeutic intervention.

MIEN1 is tightly regulated by SINE Alu methylation in its promoter

Migration and invasion enhancer 1 (MIEN1) is a novel gene involved in prostate cancer progression by enhancing prostate cancer cell migration and invasion. DNA methylation, an important epigenetic regulation, is one of the most widely altered mechanisms in prostate cancer. This phenomenon frames the basis to study the DNA methylation patterns in the promoter region of MIEN1. Bisulfite pyrosequencing demonstrates the MIEN1 promoter contains a short interspersed nuclear Alu element (SINE Alu) repeat sequence. Validation of methylation inhibition on MIEN1 was performed using nucleoside analogs and non-nucleoside inhibitors and resulted in an increase in both MIEN1 RNA and protein in normal cells. MIEN1 mRNA and protein increases upon inhibition of individual DNA methyltransferases using RNA interference technologies. Furthermore, dual luciferase reporter assays, in silico analysis, and chromatin immunoprecipitation assays identified a sequence upstream of the transcription start site that has a site for binding of the USF transcription factors. These results suggest the MIEN1 promoter has a SINE Alu region that is hypermethylated in normal cells leading to repression of the gene. In cancer, the hypomethylation of a part of this repeat, in addition to the binding of USF, results in MIEN1 expression.

MIEN1 drives breast tumor cell migration by regulating cytoskeletal-focal adhesion dynamics

Migration and invasion enhancer 1 (MIEN1) is an important regulator of cell migration and invasion. MIEN1 overexpression represents an oncogenic event that promotes tumor cell dissemination and metastasis. The underlying mechanism by which MIEN1 regulates migration and invasion has yet to be deciphered. Here, we demonstrate that MIEN1 acts as a cytoskeletal-signaling adapter protein to drive breast cancer cell migration. MIEN1 localization is concentrated underneath the actin-enriched protrusive structures of the migrating breast cancer cells. Depletion of MIEN1 led to the loss of actin-protrusive structures whereas the over-expression of MIEN1 resulted in rich and thick membrane extensions. Knockdown of MIEN1 also decreased the cell-substratum adhesion, suggesting a role for MIEN1 in actin cytoskeletal dynamics. Our results show that MIEN1 supports the transition of G-actin to F-actin polymerization and stabilizes F-actin polymers. Additionally, MIEN1 promotes cellular adhesion and actin dynamics by inducing phosphorylation of FAK at Tyr-925 and reducing phosphorylation of cofilin at Ser-3, which results in breast cancer cell migration. Collectively, our data show that MIEN1 plays an essential role in maintaining the plasticity of the dynamic membrane-associated actin cytoskeleton, which leads to an increase in cell motility. Hence, targeting MIEN1 might represent a promising means to prevent breast tumor metastasis.

miR-136 targets MIEN1 and involves the metastasis of colon cancer by suppressing epithelial-to-mesenchymal transition

MIEN1 is a novel oncogene, and it involves tumor progression in various cancer types, including colon cancer. However, the definite molecular mechanisms of MIEN1 in colon cancer progression remain to be completely elucidated. In the present study, bioinformatics prediction showed that miR-136 could be an upstream regulator of MIEN1; a luciferase assay and Western blot assay revealed that miR-136 negatively regulates MIEN1 expression via directly targeting its 3'-untranslated region sequence. Moreover, a functional assay using wound healing and transwell invasion showed that overexpressed miR-136 inhibited cell migration and invasion, and overexpression of MIEN1 partly rescued the above-mentioned effects of miR-136 in colon cancer cells. Additionally, a clinical sample assay showed that miR-136 expression was generally downregulated in colon cancer tissue, which was inversely correlated with MIEN1 expression. Furthermore, we found that miR-136 suppressed the Akt/NF-κB signaling pathway and epithelial-to-mesenchymal transition in colon cancer. These results suggest that miR-136, as a tumor suppressor, acts in tumor metastasis by suppressing MIEN1 expression in colon cancer, providing a novel target for the treatment of colon cancer.

Construction of C35 gene bait recombinants and T47D cell cDNA library

C35 is a novel tumor biomarker associated with metastasis progression. To investigate the interaction factors of C35 in its high expressed breast cancer cell lines, we constructed bait recombinant plasmids of C35 gene and T47D cell cDNA library for yeast two-hybrid screening. Full length C35 sequences were subcloned using RT-PCR from cDNA template extracted from T47D cells. Based on functional domain analysis, the full-length C35_1-348bp was also truncated into two fragments C351-153bp and C35154-348bp to avoid auto-activation. The three kinds of C35 genes were successfully amplified and inserted into pGBKT7 to construct bait recombinant plasmids pGBKT7-C351-348bp, pGBKT7-C351-153bp and pGBKT7-C35154-348bp, then transformed into Y187 yeast cells by the lithium acetate method. Auto-activation and toxicity of C35 baits were detected using nutritional deficient medium and X-α-Gal assays. The T47D cell ds cDNA was generated by SMART^TM technology and the library was constructed using in vivo recombination-mediated cloning in the AH109 yeast strain using a pGADT7-Rec plasmid. The transformed Y187/pGBKT7-C351-348bp line was intensively inhibited while the truncated Y187/pGBKT7-C35 lines had no auto-activation and toxicity in yeast cells. The titer of established cDNA library was 2 × 10⁷ pfu/mL with high transformation efficiency of 1.4 × 10⁶, and the insert size of ds cDNA was distributed homogeneously between 0.5-2.0 kb. Our research generated a T47D cell cDNA library with high titer, and the constructed two C35 "baits" contained a respective functional immunoreceptor tyrosine based activation motif (ITAM) and the conserved last four amino acids Cys-Ile-Leu-Val (CILV) motif, and therefore laid a foundation for screening the C35 interaction factors in a BC cell line.

Genes co-amplified with ERBB2 or MET as novel potential cancer-promoting genes in gastric cancer

Gastric cancer (GC), one of the most common cancers worldwide, has a high mortality rate due to limited treatment options. Identifying novel and promising molecular targets is a major challenge that must be overcome if treatment of advanced GC is to be successful. Here, we used comparative genomic hybridization and gene expression microarrays to examine genome-wide DNA copy number alterations (CNAs) and global gene expression in 38 GC samples from old and young patients. We identified frequent CNAs, which included copy number gains on chromosomes 3q, 7p, 8q, 20p, and 20q and copy number losses on chromosomes 19p and 21p. The most frequently gained region was 7p21.1 (55%), whereas the most frequently deleted region was 21p11.1 (50%). Recurrent highly amplified regions 17q12 and 7q31.1-7q31.31 harbored two well-known oncogenes: ERBB2 and MET. Correlation analysis of CNAs and gene expression levels identified CAPZA2 (co-amplified with MET) and genes GRB7, MIEN1, PGAP3, and STARD3 (co-amplified with ERBB2) as potential candidate cancer-promoting genes (CPGs). Public dataset analysis confirmed co-amplification of these genes with MET or ERBB2 in GC tissue samples, and revealed that high expression (except for PGAP3) was significantly associated with shorter overall survival. Knockdown of these genes using small interfering RNA led to significant suppression of GC cell proliferation and migration. Reduced GC cell proliferation mediated by CAPZA2 knockdown was attributable to attenuated cell cycle progression and increased apoptosis. This study identified novel candidate CPGs co-amplified with MET or ERBB2, and suggests that they play a functional role in GC.

Loss of Kaiso expression in breast cancer cells prevents intra-vascular invasion in the lung and secondary metastasis

The metastatic activity of breast carcinomas results from complex genetic changes in epithelial tumor cells and accounts for 90% of deaths in affected patients. Although the invasion of the local lymphatic vessels and veins by malignant breast tumor cells and their subsequent metastasis to the lung, has been recognized, the mechanisms behind the metastatic activity of breast tumor cells to other distal organs and the pathogenesis of metastatic cancer are not well understood. In this study, we utilized derivatives of the well-established and highly metastatic triple negative breast cancer (TNBC) cell line MDA-MB-231 (MDA-231) to study breast tumor metastasis in a mouse model. These MDA-231 derivatives had depleted expression of Kaiso, a POZ-ZF transcription factor that is highly expressed in malignant, triple negative breast cancers. We previously reported that Kaiso depletion attenuates the metastasis of xenografted MDA-231 cells. Herein, we describe the pathological features of the metastatic activity of parental (Kaiso^positive) versus Kaiso^depleted MDA-231 cells. Both Kaiso^positive and Kaiso^depleted MDA-231 cells metastasized from the original tumor in the mammary fat pad to the lung. However, while Kaiso^positive cells formed large masses in the lung parenchyma, invaded large pulmonary blood vessels and formed secondary metastases and large tumors in the distal organs, Kaiso^depleted cells metastasized only to the lung where they formed small metastatic lesions. Importantly, intravascular invasion and secondary metastases in distal organs were not observed in mice xenografted with Kaiso^depleted cells. It thus appears that the lung may constitute a barrier for less invasive breast tumors such as the Kaiso^depleted TNBC cells; this barrier may limit tumor growth and prevents Kaiso^depleted TNBC cells from invading the pulmonary blood vessels and forming secondary metastases in distal organs.

Macrophage migration inhibitory factor interacts with thioredoxin-interacting protein and induces NF-κB activity

The nuclear factor kappa B (NF-κB) pathway is pivotal in controlling survival and apoptosis of cancer cells. Macrophage migration inhibitory factor (MIF), a cytokine that regulates the immune response and tumorigenesis under inflammatory conditions, is upregulated in various tumors. However, the intracellular functions of MIF are unclear. In this study, we found that MIF directly interacted with thioredoxin-interacting protein (TXNIP), a tumor suppressor and known inhibitor of NF-κB activity, and MIF significantly induced NF-κB activation. MIF competed with TXNIP for NF-κB activation, and the intracellular MIF induced NF-κB target genes, including c-IAP2, Bcl-xL, ICAM-1, MMP2 and uPA, by inhibiting the interactions between TXNIP and HDACs or p65. Furthermore, we identified the interaction motifs between MIF and TXNIP via site-directed mutagenesis of their cysteine (Cys) residues. Cys⁵⁷ and Cys⁸¹ of MIF and Cys³⁶ and Cys¹²⁰ of TXNIP were responsible for the interaction. MIF reversed the TXNIP-induced suppression of cell proliferation and migration. Overall, we suggest that MIF induces NF-κB activity by counter acting the inhibitory effect of TXNIP on the NF-κB pathway via direct interaction with TXNIP. These findings reveal a novel intracellular function of MIF in the progression of cancer.

C35 is overexpressed in colorectal cancer and is associated tumor invasion and metastasis

The aim of this study was to investigate the expression of C35, an oncogene previously found in breast and prostate cancers, and its clinicopathological significance in colorectal cancer (CRC). Qualitative and quantitative detection of C35 mRNA expression was performed using reverse transcription-PCR (RT-PCR) and real-time PCR. C35 protein expression was determined using immunohistochemistry. C35 mRNA was detected in none of 10 normal colorectal tissue samples, 55 of 65 (84.6%) CRC tissue samples, and 43 of 55 (78.2%) adjacent non-cancerous tissue samples. In addition, the level of C35 mRNA in CRC tissue samples was markedly higher than that in tumor adjacent non-cancerous tissue samples. C35 protein expression was detected in 58 of 80 (72.5%) CRC tissue samples and was closely associated with tumor serosal invasion, lymphnode metastasis, and an advanced Dukes stage. These results suggest that C35 might serve as a biomarker or therapeutic target for management of CRC.

MicroRNA in prostate cancer

In the United States of America male prostate cancer (PCa) is the most dominant malignancy and the second highest cause of cancer-related mortality risk compared to lung and colon cancers. MicroRNAs (miRNAs) are a class of endogenously expressed small, non-coding, single-stranded RNA which function as regulators of gene expression. They influence various physiological and pathophysiological processes. In this review, we focus on the regulation of miRNAs in prostate cancer and their mechanisms which contribute to prostate carcinogenesis. The relation of miRNAs with androgen signaling is highlighted and the prospects of miRNAs for clinical therapies are discussed.

Gene Expression-Genotype Analysis Implicates GSDMA, GSDMB, and LRRC3C as Contributors to Inflammatory Bowel Disease Susceptibility

To investigate the biological foundation of the inflammatory bowel disease (IBD), ulcerative colitis and Crohn's disease, susceptibility locus rs2872507, we have investigated the expression of 13 genes using ileal and colonic biopsies from patients with IBD (inflamed and noninflamed mucosa) or from individuals without IBD (noninflamed mucosa). The susceptibility allele was consistently associated with reduced expression of GSDMB (P = 4.1 × 10⁻³–7.2 × 10⁻¹⁰). The susceptibility allele was also associated with the increased expression of GSDMA (P = 1.6 × 10⁻⁴) and LRRC3C (P = 7.8 × 10⁻⁶) in colon tissue from individuals without IBD and with the reduced expression of PGAP3 (IBD; P = 2.0 × 10⁻³) and ZPBP2 (Crohn's disease; P = 7.7 × 10⁻⁴) in noninflamed ileum. Inflammation resulted in the reduced colonic expression of ERBB2, GRB7, MIEN1, and PGAP3 (P = 1.0 × 10⁻⁴–1.0 × 10⁻⁹) and the increased colonic expression of IKZF3 and CSF3 (P = 2.4 × 10⁻⁷–3.5 × 10⁻⁸). Based on our results and published findings on GSDMA, GSDMB, LRRC3C, and related proteins, we propose that this locus in part affects IBD susceptibility via effects on apoptosis and cell proliferation and believe this hypothesis warrants further experimental investigation.

MIEN1, a novel interactor of Annexin A2, promotes tumor cell migration by enhancing AnxA2 cell surface expression

Background

Migration and invasion enhancer 1 (MIEN1) is a novel gene found to be abundantly expressed in breast tumor tissues and functions as a critical regulator of tumor cell migration and invasion to promote systemic metastases. Previous studies have identified post-translational modifications by isoprenylation at the C-terminal tail of MIEN1 to favor its translocation to the inner leaflet of plasma membrane and its function as a membrane-bound adapter molecule. However, the exact molecular events at the membrane interface activating the MIEN1-driven tumor cell motility are vaguely understood.

Methods

MIEN1 was first studied using in-silico analysis on available RNA sequencing data of human breast tissues and its expression was ascertained in breast cells. We performed several assays including co-immunoprecipitation, wound healing, western blotting and immunofluorescence to decipher the molecular events involved in MIEN1-mediated tumor cell migration.

Results

Clinically, MIEN1 is predominantly overexpressed in Her-2 and luminal B subtypes of breast tumors, and its increased expression correlates with poor disease free survival. Molecular studies identified a phosphorylation-dependent activation signal in the immunoreceptor tyrosine based activation motif (ITAM) of MIEN1 and the phosphorylation-deficient MIEN1-mutants (Y39F/50 F) to regulate filopodia generation, migration and invasion. We found that ITAM-phosphorylation of MIEN1 is significantly impaired in isoprenylation-deficient MIEN1 mutants indicating that prenylation of MIEN1 and membrane association is required for cross-phosphorylation of tyrosine residues. Furthermore, we identified MIEN1 as a novel interactor of Annexin A2 (AnxA2), a Ca²⁺ -dependent phospholipid binding protein, which serves as an extracellular proteolytic center regulating plasmin generation. Fluorescence resonance energy transfer (FRET) confirmed that MIEN1 physically interacts with AnxA2 and functional studies revealed that they mutually cooperate to accentuate tumor cell motility. Interestingly, our study identified that ectopic overexpression of MIEN1 significantly enhances Tyr23-phosphorylation on AnxA2, thereby stimulating cell surface translocation of AnxA2 and catalyzing the activation of its proteolytic activity.

Conclusion

Our data show that the presence and interaction of both MIEN1 and AnxA2 in breast tumors are crucial drivers of cell motility. Our study has now deciphered a novel regulatory network governing the vicious process of breast tumor cell invasion-metastasis, and findings suggest MIEN1-AnxA2 as prospective targets to counter the deadly disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0428-8) contains supplementary material, which is available to authorized users.

Mechanism-based proteomic screening identifies targets of thioredoxin-like proteins

Thioredoxin (Trx)-fold proteins are protagonists of numerous cellular pathways that are subject to thiol-based redox control. The best characterized regulator of thiols in proteins is Trx1 itself, which together with thioredoxin reductase 1 (TR1) and peroxiredoxins (Prxs) comprises a key redox regulatory system in mammalian cells. However, there are numerous other Trx-like proteins, whose functions and redox interactors are unknown. It is also unclear if the principles of Trx1-based redox control apply to these proteins. Here, we employed a proteomic strategy to four Trx-like proteins containing CXXC motifs, namely Trx1, Rdx12, Trx-like protein 1 (Txnl1) and nucleoredoxin 1 (Nrx1), whose cellular targets were trapped in vivo using mutant Trx-like proteins, under conditions of low endogenous expression of these proteins. Prxs were detected as key redox targets of Trx1, but this approach also supported the detection of TR1, which is the Trx1 reductant, as well as mitochondrial intermembrane proteins AIF and Mia40. In addition, glutathione peroxidase 4 was found to be a Rdx12 redox target. In contrast, no redox targets of Txnl1 and Nrx1 could be detected, suggesting that their CXXC motifs do not engage in mixed disulfides with cellular proteins. For some Trx-like proteins, the method allowed distinguishing redox and non-redox interactions. Parallel, comparative analyses of multiple thiol oxidoreductases revealed differences in the functions of their CXXC motifs, providing important insights into thiol-based redox control of cellular processes.

MIEN1 promotes oral cancer progression and implicates poor overall survival

Oral squamous cell carcinoma is a highly malignant tumor with the potential to invade local and distant sites and promote lymph node metastasis. Major players underlying the molecular mechanisms behind tumor progression are yet to be fully explored. Migration and invasion enhancer 1 (MIEN1), a novel protein overexpressed in various cancers, facilitates cell migration and invasion. In the present study we investigated the expression and role of MIEN1 in oral cancer progression using an in vitro model, patient derived oral tissues and existing TCGA data. Expression analysis using immortalized normal and cancer cells demonstrated increased expression of MIEN1 in cancer. Assays performed after MIEN1 knockdown in OSC-2 cells showed decreased migration, invasion and filopodia formation; while MIEN1 overexpression in DOK cells increased these characteristics and also up-regulated some Akt/NF-κB effectors, thereby suggesting an important role for MIEN1 in oral cancer progression. Immunohistochemical staining and analyses of oral tissue specimens, collected from patients over multiple visits, revealed significantly more staining in severe dysplasia and squamous cell carcinoma compared to mildly dysplastic or hyperplastic tissues. Finally, this was corroborated with the TCGA dataset, where MIEN1 expression was not only higher in intermediate and high grade cancer with significantly lower survival but also correlated with smoking. In summary, we demonstrate that MIEN1 expression not only positively correlates with oral cancer progression but also seems to be a critical molecular determinant in migration and invasion of oral cancer cells, thereby, playing a possible role in their metastatic dissemination.

SYK is a candidate kinase target for the treatment of advanced prostate cancer

Improved targeted therapies are needed to combat metastatic prostate cancer. Here, we report the identification of the spleen kinase SYK as a mediator of metastatic dissemination in zebrafish and mouse xenograft models of human prostate cancer. Although SYK has not been implicated previously in this disease, we found that its expression is upregulated in human prostate cancers and associated with malignant progression. RNAi-mediated silencing prevented invasive outgrowth in vitro and bone colonization in vivo, effects that were reversed by wild-type but not kinase-dead SYK expression. In the absence of SYK expression, cell surface levels of the progression-associated adhesion receptors integrin α2β1 and CD44 were diminished. RNAi-mediated silencing of α2β1 phenocopied SYK depletion in vitro and in vivo, suggesting an effector role for α2β1 in this setting. Notably, pharmacologic inhibitors of SYK kinase currently in phase I-II trials for other indications interfered similarly with the invasive growth and dissemination of prostate cancer cells. Our findings offer a mechanistic rationale to reposition SYK kinase inhibitors for evaluation in patients with metastatic prostate cancer.

MicroRNA-940 suppresses prostate cancer migration and invasion by regulating MIEN1

Background

MicroRNAs (miRNAs) are crucial molecules that regulate gene expression and hence pathways that are key to prostate cancer progression. These non-coding RNAs are highly deregulated in prostate cancer thus facilitating progression of the disease. Among the many genes that have gained importance in this disease, Migration and invasion enhancer 1 (MIEN1), a novel gene located next to HER2/neu in the 17q12 amplicon of the human chromosome, has been shown to enhance prostate cancer cell migration and invasion, two key processes in cancer progression. MIEN1 is differentially expressed between normal and cancer cells and tissues. Understanding the regulation of MIEN1 by microRNA may enable development of better targeting strategies.

Methods

The miRNAs that could target MIEN1 were predicted by in silico algorithms and microarray analysis. The validation for miRNA expression was performed by qPCR and northern blotting in cells and by in situ hybridization in tissues. MIEN1 and levels of other molecules upon miRNA regulation was determined by Western blotting, qPCR, and immunofluorescence. The functional effects of miRNA on cells were determined by wound healing cell migration, Boyden chamber cell invasion, clonal and colony formation assays. For knockdown or overexpression of the miRNA or overexpression of MIEN1 3′UTR, cells were transfected with the oligomiRs and plasmids, respectively.

Results

A novel miRNA, hsa-miR-940 (miR-940), identified and validated to be highly expressed in immortalized normal cells compared to cancer cells, is a regulator of MIEN1. Analysis of human prostate tumors and their matched normal tissues confirmed that miR-940 is highly expressed in the normal tissues compared to its low to negligible expression in the tumors. While MIEN1 is a direct target of miR-940, miR-940 alters MIEN1 RNA, in a quantity as well as cell dependent context, along with altering its downstream effectors. The miR-940 inhibited migratory and invasive potential of cells, attenuated their anchorage-independent growth ability, and increased E-cadherin expression, implicating its role in mesenchymal-to-epithelial transition (MET).

Conclusions

These results, for the first time, implicate miR-940, a regulator of MIEN1, as a promising novel diagnostic and prognostic tool for prostate cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-250) contains supplementary material, which is available to authorized users.

The interaction between C35 and ΔNp73 promotes chemo-resistance in ovarian cancer cells

Background:

The purpose of this study was to characterise the oncogenic roles of C35, a novel protein binding partner of ΔNp73, in ovarian cancer and to investigate the functional significance of C35–ΔNp73 interaction in the regulation of chemo-resistance.

Methods:

C35 expression was evaluated by quantitative real-time PCR in human ovarian cancer tissues and cell lines. The aggressiveness of ovarian cancer cells overexpressing C35 was examined by cell proliferation, migration, soft agar and nude mouse xenograft. The significance of C35–ΔNp73 interaction in chemo-resistance was evaluated by apoptosis assays and cell viability after cisplatin treatment.

Results:

The expression of C35 was significantly enhanced in human ovarian cancer tissues. Overexpression of C35 augmented proliferation, migration and tumourigenicity in ovarian cancer cell lines. C35 knockdown inhibited cell motility and cell growth. The co-expression of C35 and ΔNp73 by transient or stable transfection in ovarian cancer cells induced greater resistance to cisplatin treatment than did transfection with C35 or ΔNp73 alone. The cisplatin resistance was demonstrated to be caused by increased AKT and NFκB activity induced by C35–ΔNp73.

Conclusion:

Our results suggest that ΔNp73 might cooperate with C35 to promote tumour progression and contribute to cisplatin resistance in ovarian cancer cells. Future studies of the functional roles of ΔNp73 and C35 will provide insight that will aid in the establishment of new strategies and more effective therapies.

Biomolecular events in cancer revealed by attractor metagenes

Mining gene expression profiles has proven valuable for identifying signatures serving as surrogates of cancer phenotypes. However, the similarities of such signatures across different cancer types have not been strong enough to conclude that they represent a universal biological mechanism shared among multiple cancer types. Here we present a computational method for generating signatures using an iterative process that converges to one of several precise attractors defining signatures representing biomolecular events, such as cell transdifferentiation or the presence of an amplicon. By analyzing rich gene expression datasets from different cancer types, we identified several such biomolecular events, some of which are universally present in all tested cancer types in nearly identical form. Although the method is unsupervised, we show that it often leads to attractors with strong phenotypic associations. We present several such multi-cancer attractors, focusing on three that are prominent and sharply defined in all cases: a mesenchymal transition attractor strongly associated with tumor stage, a mitotic chromosomal instability attractor strongly associated with tumor grade, and a lymphocyte-specific attractor.

Cancer is known to be characterized by several unifying biological capabilities or “hallmarks.” However, attempts to computationally identify patterns, such as gene expression signatures, shared across many different cancer types have been largely unsuccessful. A typical approach has been to classify samples into mutually exclusive subtypes, each of which is characterized by a particular gene signature. Although occasional similarities of such signatures in different cancer types exist, these similarities have not been sufficiently strong to conclude that they reflect the same biological event. By contrast, we have developed a computational methodology that has identified some signatures of co-expressed genes exhibiting remarkable similarity across many different cancer types. These signatures appear as stable “attractors” of an iterative computational procedure that tends to collect mutually associated genes, so that its convergence can point to the core (“heart”) of the underlying biological co-expression mechanism. One of these “pan-cancer” attractors corresponds to a transdifferentiation of cancer cells empowering them with invasiveness and motility. Another represents a mitotic chromosomal instability of cancer cells. A third attractor is lymphocyte-specific.

Solution structure of the oncogenic MIEN1 protein reveals a thioredoxin-like fold with a redox-active motif

The novel tumor biomarker MIEN1, identified by representational difference analysis, is overexpressed in breast cancer and prostate cancer. MIEN1 is considered an oncogenic protein, because MIEN1 overexpression functionally enhances migration and invasion of tumor cells via modulating the activity of AKT. However, the structure and molecular function of MIEN1 is little understood. Here, we report the solution structure of MIEN1, which adopts a thioredoxin-like fold with a redox-active motif. Comparison of backbone chemical shifts showed that most of the residues for both oxidized and reduced MIEN1 possessed the same backbone conformation, with differences limited to the active motif and regions in proximity. The redox potential of this disulfide bond was measured as -225 mV, which compares well with that of disulfides for other thioredoxin-like proteins. Overall, our results suggest that MIEN1 may have an important regulatory role in phosphorylation of AKT with its redox potential.

Reciprocal regulation of annexin A2 and EGFR with Her-2 in Her-2 negative and herceptin-resistant breast cancer

Alternative survival pathways are commonly seen to be upregulated upon inhibition of receptor tyrosine kinases (RTK), including Her-2. It is established that treatment with Herceptin leads to selective overexpression and activation of epidermal growth factor receptor (EGFR) and Src which further contributes to oncogenesis in Herceptin resistant and triple negative breast cancer (TNBC) patients. Here, we show a co-regulated upregulation in the expression of Annexin A2 (AnxA2), a known substrate of Src and one of the regulators of EGFR receptor endocytosis, in Herceptin resistant and Her-2 negative breast cancer. Immunohistochemical expression analysis revealed a reciprocal regulation between Her-2 and AnxA2 in breast cancer clinical samples as well as in cell lines as confirmed by protein and RNA analysis. The siRNA and Herceptin mediated downregulation/inhibition of Her-2 in Her-2 amplified cells induced AnxA2 expression and membrane translocation. In this study we report a possible involvement of AnxA2 in maintaining constitutively activated EGFR downstream signaling intermediates and hence in cell proliferation, migration and viability. This effect was consistent in Herceptin resistant JIMT-1 cells as well as in Her-2 negative breast cancer. The siRNA mediated AnxA2 downregulation leads to increased apoptosis, decreased cell viability and migration. Our studies further indicate the role of AnxA2 in EGFR-Src membrane bound signaling complex and ligand induced activation of downstream signaling pathways. Targeting this AnxA2 dependent positive regulation of EGFR signaling cascade may be of therapeutic value in Her-2 negative breast cancer.

Oncogenic activation in prostate cancer progression and metastasis: Molecular insights and future challenges

Prostate cancer is a leading cause of death among men in the United States, and currently early diagnosis and appropriate treatment remain key approaches for patient care. Molecularly prostate cancer cells carry multiple perturbations that generate malignant phenotype capable of uncontrolled growth, survival, and invasion-metastasis to other organs. These alterations are acquired both by genetic and epigenetic changes in tumor cells resulting in the activation of growth factor receptors, signaling proteins, kinases, transcription factors and coregulators, and multiple proteases required for the progression of the disease. Recent advances provide novel insights into the molecular functions of these oncogenic activators, implicating potential therapeutic targeting opportunities for the treatment of prostate cancer.

Prenylated c17orf37 induces filopodia formation to promote cell migration and metastasis

Post-translational modification by covalent attachment of isoprenoid lipids (prenylation) regulates the functions and biological activities of several proteins implicated in the oncogenic transformation and metastatic progression of cancer. The largest group of prenylated proteins contains a CAAX motif at the C-terminal that serves as a substrate for a series of post-translational modifications that convert these otherwise hydrophilic proteins to lipidated proteins, thus facilitating membrane association. C17orf37 (chromosome 17 open reading frame 37), also known as C35/Rdx12/MGC14832, located in the 17q12 amplicon, is overexpressed in human cancer, and its expression correlates with the migratory and invasive phenotype of cancer cells. Here we show that C17orf37 contains a functional CAAX motif and is post-translationally modified by protein geranylgeranyltransferase-I (GGTase-I). Geranylgeranylation of C17orf37 at the CAAX motif facilitates association of the protein to the inner leaflet of plasma membrane, enhances migratory phenotype of cells by inducing increased filopodia formation, and potentiates directional migration. A prenylation-deficient mutant of C17orf37 is functionally inactive and fails to trigger dissemination of tail vein-injected cells in a mouse model of metastasis. These findings demonstrate that prenylation is required for the function of the C17orf37 protein in cancer cells and imply that the post-translational modification may functionally regulate metastatic progression of disease.

High-resolution comparative genomic hybridization of inflammatory breast cancer and identification of candidate genes

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive form of BC poorly defined at the molecular level. We compared the molecular portraits of 63 IBC and 134 non-IBC (nIBC) clinical samples.

METHODOLOGY/FINDINGS

Genomic imbalances of 49 IBCs and 124 nIBCs were determined using high-resolution array-comparative genomic hybridization, and mRNA expression profiles of 197 samples using whole-genome microarrays. Genomic profiles of IBCs were as heterogeneous as those of nIBCs, and globally relatively close. However, IBCs showed more frequent "complex" patterns and a higher percentage of genes with CNAs per sample. The number of altered regions was similar in both types, although some regions were altered more frequently and/or with higher amplitude in IBCs. Many genes were similarly altered in both types; however, more genes displayed recurrent amplifications in IBCs. The percentage of genes whose mRNA expression correlated with CNAs was similar in both types for the gained genes, but ∼7-fold lower in IBCs for the lost genes. Integrated analysis identified 24 potential candidate IBC-specific genes. Their combined expression accurately distinguished IBCs and nIBCS in an independent validation set, and retained an independent prognostic value in a series of 1,781 nIBCs, reinforcing the hypothesis for a link with IBC aggressiveness. Consistent with the hyperproliferative and invasive phenotype of IBC these genes are notably involved in protein translation, cell cycle, RNA processing and transcription, metabolism, and cell migration.

CONCLUSIONS

Our results suggest a higher genomic instability of IBC. We established the first repertory of DNA copy number alterations in this tumor, and provided a list of genes that may contribute to its aggressiveness and represent novel therapeutic targets.

Transcriptional control of the ERBB2 amplicon by ERRalpha and PGC-1beta promotes mammary gland tumorigenesis

Overexpression of ERBB2 and its neighboring genes on chromosome 17 occurs in approximately 25% of breast tumors and is associated with poor prognosis. While amplification of the 17q12-21 chromosomal region often correlates with an increase in the transcriptional rates of the locus, the molecular mechanisms and the factors involved in the coordinated expression of genes residing within the ERBB2 amplicon remain largely unknown. Here we demonstrate that estrogen-related receptor α (ERRα, NR3B1) and its coregulator PGC-1β are key effectors in this process. Using a mouse model of ERBB2-initiated mammary tumorigenesis, we first show that ablation of ERRα significantly delays ERBB2-induced tumor development and lowers the levels of amplicon transcripts. Chromosome 17q-wide binding site location analyses in human breast cancer cells show preferential recruitment of ERRα to DNA segments associated with the ERBB2 amplicon. Furthermore, ERRα directs the co-recruitment of the coactivator PGC-1β to segments in the 17q12 region and the recruitment of RNA polymerase II to the promoters of the ERBB2 and coamplified genes. ERRα and PGC-1β also participate in the de-repression of ERBB2 expression through competitive genomic cross-talk with estrogen receptor α (ERα) and, as a consequence, influence tamoxifen sensitivity in breast cancer cells. Taken together, our results suggest that ERRα and PGC-1β are key players in the etiology of malignant breast cancer by coordinating the transcriptional regulation of genes located in the 17q12 region, a process that also involves interference with the repressive function of ERα on ERBB2 expression.

Resonance assignments of human C35 (C17orf37) protein, a novel tumor biomarker

A new tumor-specific target, termed C35 (C17orf37), has been identified by representational difference analysis of tumor and normal human mammary cell lines. C35 protein is considered to be an important target for cancer therapy, since the over expression of C35 functionally enhances migration and invasion of tumor cells. Here we report the NMR resonance assignments of C35 protein for further structural determination and functional studies.

PTRF-cavin-1 expression decreases the migration of PC3 prostate cancer cells: role of matrix metalloprotease 9

Caveolae are specialized plasma membrane subdomains with a distinct lipid and protein composition, which play an essential role in cell physiology by performing trafficking and signalling functions. The structure and functions of caveolae have been shown to require caveolin-1, a major protein component of caveolae. Caveolin-1 expression and secretion are increased in metastatic prostate cancer, and caveolin-1 seems to contribute to prostate cancer growth and metastasis. Recently, a cytoplasmic protein named PTRF (Polymerase I and Transcript Release Factor) or cavin-1 was found to be required, in concert with caveolin-1, for the formation and functions of caveolae. Genetic ablation of PTRF results in loss of caveolae while caveolin-1 is still expressed, albeit at reduced level, but associates with flat plasma membrane. In metastatic PC3 prostate cancer cells that express abundant caveolin-1 but no PTRF, heterologous PTRF expression restores caveola formation and caveolin-1 distribution (Hill et al., 2008; Cell 132, 113-124). We now show that PTRF/cavin-1-expressing PC3 cells exhibit decreased migration, and that this effect is mediated by reduced MMP9 production. PTRF/cavin-1, and to a lesser extent, cavin-2, -3, and -4 all decreased MMP9. We further show that the PTRF/cavin-1-mediated reduction of MMP9 production is independent of caveola formation. Taken together, our results suggest that PTRF/cavin-1 expression alters prostate cancer aggressiveness.

A gene on the HER2 amplicon, C35, is an oncogene in breast cancer whose actions are prevented by inhibition of Syk

Background:

C35 is a 12 kDa membrane-anchored protein endogenously over-expressed in many invasive breast cancers. C35 (C17orf37) is located on the HER2 amplicon, between HER2 and GRB7. The function of over-expressed C35 in invasive breast cancer is unknown.

Methods:

Tissue microarrays containing 122 primary human breast cancer specimens were used to examine the association of C35 with HER2 expression. Cell lines over-expressing C35 were generated and tested for evidence of cell transformation in vitro.

Results:

In primary breast cancers high levels of C35 mRNA expression were associated with HER2 gene amplification. High levels of C35 protein expression were associated with hallmarks of transformation, such as, colony growth in soft agar, invasion into collagen matrix and formation of large acinar structures in three-dimensional (3D) cell cultures. The transformed phenotype was also associated with characteristics of epithelial to mesenchymal transition, such as adoption of spindle cell morphology and down-regulation of epithelial markers, such as E-cadherin and keratin-8. Furthermore, C35-induced transformation in 3D cell cultures was dependent on Syk kinase, a downstream mediator of signalling from the immunoreceptor tyrosine-based activation motif, which is present in C35.

Conclusion:

C35 functions as an oncogene in breast cancer cell lines. Drug targeting of C35 or Syk kinase might be helpful in treating a subset of patients with HER2-amplified breast cancers.

Signal transducer and activator of transcription 6 (STAT6) is a novel interactor of annexin A2 in prostate cancer cells

Annexin A2 (AnxA2) is a multifunctional Ca(2+)-dependent phospholipid-binding protein, and its overexpression is implicated in malignant transformation of several cancers. In prostate cancer, however, the expression of AnxA2 is lost in prostate intraepithelial neoplasia and reappears in the high-grade tumors, suggesting a complex regulation of AnxA2 in the prostate microenvironment. Since a majority of the biological functions of AnxA2 are mediated by its interaction with other proteins, we performed a yeast two-hybrid assay to search for novel interactors of AnxA2. Our studies revealed that signal transducer and activator of transcription 6 (STAT6), a member of the STAT family of transcription factors, is a binding partner of AnxA2. We confirmed AnxA2-STAT6 interaction by in vitro co-immunoprecipitation and fluorescence resonance energy transfer (FRET) studies and demonstrated that AnxA2 interacts with phosphorylated STAT6. Furthermore, chromatin immunoprecipitation (ChIP) assay revealed that AnxA2 is associated with the STAT6 DNA-binding complex, and luciferase reporter assays demonstrated that AnxA2 upregulates the activity of STAT6. Upon interleukin-4 treatment, AnxA2 stabilizes the cytosolic levels of phosphorylated STAT6 and promotes its nuclear entry. These findings suggest that AnxA2-STAT6 interactions could have potential implications in prostate cancer progression. This report is the first to demonstrate the interaction of AnxA2 with STAT6 and suggests a possible mechanism by which AnxA2 contributes to the metastatic processes of prostate cancer.