Expression of tenascin-C and its isoforms in the breast

Analyses of the MYBL1 Gene in Triple Negative Breast Cancer: Evidence of Regulation of the VCPIP1 Gene and Identification of a Specific Exon Overexpressed in Tumor Cell Lines

Previous data show that the knockdown of the MYBL1 gene in the MDA-MB-231 cell line leads to the downregulation of VCPIP1 gene expression. In addition, MYBL1 and VCPIP1 genes are co-expressed and dysregulated in some of the same triple negative breast cancer patient samples. We propose that the co-expression of the two genes is attributed to the MYBL1 transcription factor regulation of the VCPIP1 gene. We identify the MYBL1 transcription factor binding site upstream of the VCPIP1 start site and show that the MYBL1 protein can bind to the sequence identified in the VCPIP1 promoter region. Combined with the results from the knockdown study, these data support the ability of MYBL1 to regulate the VCPIP1 gene. The VCPIP1 gene functions as a deubiquitinating enzyme involved in DNA repair, protein positioning, and the assembly of the Golgi apparatus during mitotic signaling. The transcriptional regulation of VCPIP1 by the MYBL1 gene could implicate MYBL1 in these processes, which might contribute to tumor processes in TNBC. Although both genes are involved in cell cycle regulatory mechanisms, converging signaling mechanisms have not been identified. In a separate study, we performed sequence alignment of the MYBL1 transcript variants and identified an exon unique to the canonical variant. Probes that specifically target the unique MYBL1 exon show that the exon is overexpressed in tumor cell lines compared to non-tumor breast cells. We are classifying this unique MYBL1 exon as a tumor-associated exon.

RBM10 loss induces aberrant splicing of cytoskeletal and extracellular matrix mRNAs and promotes metastatic fitness

RBM10 modulates transcriptome-wide cassette exon splicing. Loss-of-function RBM10 mutations are enriched in thyroid cancers with distant metastases. Analysis of transcriptomes and genes mis-spliced by RBM10 loss showed pro-migratory and RHO/RAC signaling signatures. RBM10 loss increases cell velocity. Cytoskeletal and ECM transcripts subject to exon-inclusion events included vinculin (VCL), tenascin C (TNC) and CD44. Knockdown of the VCL exon inclusion transcript in RBM10-null cells reduced cell velocity, whereas knockdown of TNC and CD44 exon-inclusion isoforms reduced invasiveness. RAC1-GTP levels were increased in RBM10-null cells. Mouse Hras G12V /Rbm1O KO thyrocytes develop metastases that are reversed by RBM10 or by combined knockdown of VCL, CD44 and TNC inclusion isoforms. Thus, RBM10 loss generates exon inclusions in transcripts regulating ECM-cytoskeletal interactions, leading to RAC1 activation and metastatic competency. Moreover, a CRISPR-Cas9 screen for synthetic lethality with RBM10 loss identified NFkB effectors as central to viability, providing a therapeutic target for these lethal thyroid cancers.

Tenascin-C as a potential biomarker and therapeutic target for esophageal squamous cell carcinoma

PURPOSE

To establish a prognostic model of esophageal squamous cell carcinoma (ESCC) patients based on tenascin-C (TNC) expression level and clinicopathological characteristics, and to explore the therapeutic potential of TNC inhibition.

METHODS

The expression of TNC was detected using immunohistochemistry (IHC) in 326 ESCC specimens and 50 normal esophageal tissues. Prognostic factors were determined by Cox regression analyses and were incorporated to establish the nomogram. The effects of TNC knockdown on ESCC cells were assessed in vitro and in vivo. Transcriptome sequencing (RNA-seq) and gene set enrichment analysis (GSEA) were performed to reveal signaling pathways regulated by TNC knockdown. The therapeutic significance of TNC knockdown combined with small-molecule inhibitors on cell proliferation was examined.

RESULTS

TNC protein was highly expressed in 48.77 % of ESCC tissues compared to only 2 % in normal esophageal epithelia (p < 0.001). The established nomogram model, based on TNC expression, pT stage, and lymph node metastasis, showed good performance on prognosis evaluation. More importantly, the reduction of TNC expression inhibited tumor cell proliferation and xenograft growth, and mainly down-regulated signaling pathways involved in tumor growth, hypoxia signaling transduction, metabolism, infection, etc. Knockdown of TNC enhanced the inhibitory effect of inhibitors targeting ErbB, PI3K-Akt, Ras and MAPK signaling pathways.

CONCLUSION

The established nomogram may be a promising model for survival prediction in ESCC. Reducing TNC expression enhanced the sensitivity of ESCC cells to inhibitors of Epidermal Growth Factor Receptor (EGFR) and downstream signaling pathways, providing a novel combination therapy strategy.

Identification and Characterization of Immunogene-Related Alternative Splicing Patterns and Tumor Microenvironment Infiltration Patterns in Breast Cancer

Alternative splicing (AS) plays a crucial role in tumor development and tumor microenvironment (TME) formation. However, our current knowledge about AS, especially immunogene-related alternative splicing (IGAS) patterns in cancers, remains limited. Herein, we identified and characterized post-transcriptional mechanisms of breast cancer based on IGAS, TME, prognosis, and immuno/chemotherapy. We screened the differentially spliced IGAS events and constructed the IGAS prognostic model (p-values < 0.001, AUC = 0.939), which could be used as an independent prognostic factor. Besides, the AS regulatory network suggested a complex cooperative or competitive relationship between splicing factors and IGAS events, which explained the diversity of splice isoforms. In addition, more than half of the immune cells displayed varying degrees of infiltration in the IGAS risk groups, and the prognostic characteristics of IGAS demonstrated a remarkable and consistent trend correlation with the infiltration levels of immune cell types. The IGAS risk groups showed substantial differences in the sensitivity of immunotherapy and chemotherapy. Finally, IGAS clusters defined by unsupervised cluster analysis had distinct prognostic patterns, suggesting an essential heterogeneity of IGAS events. Significant differences in immune infiltration and unique prognostic capacity of immune cells were also detected in each IGAS cluster. In conclusion, our comprehensive analysis remarkably enhanced the understanding of IGAS patterns and TME in breast cancer, which may help clarify the underlying mechanisms of IGAS in neoplasia and provide clues to molecular mechanisms of oncogenesis and progression.

The Functional Role of Extracellular Matrix Proteins in Cancer

The extracellular matrix (ECM) is highly dynamic as it is constantly deposited, remodeled and degraded to maintain tissue homeostasis. ECM is a major structural component of the tumor microenvironment, and cancer development and progression require its extensive reorganization. Cancerized ECM is biochemically different in its composition and is stiffer compared to normal ECM. The abnormal ECM affects cancer progression by directly promoting cell proliferation, survival, migration and differentiation. The restructured extracellular matrix and its degradation fragments (matrikines) also modulate the signaling cascades mediated by the interaction with cell-surface receptors, deregulate the stromal cell behavior and lead to emergence of an oncogenic microenvironment. Here, we summarize the current state of understanding how the composition and structure of ECM changes during cancer progression. We also describe the functional role of key proteins, especially tenascin C and fibronectin, and signaling molecules involved in the formation of the tumor microenvironment, as well as the signaling pathways that they activate in cancer cells.

Profiles of alternative splicing landscape in breast cancer and their clinical significance: an integrative analysis based on large-sequencing data

Background

Alternative splicing (AS) is closely correlated with the initiation and progression of carcinoma. The systematic analysis of its biological and clinical significance in breast cancer (BRCA) is, however, lacking.

Methods

Clinical data and RNA-seq were obtained from the TCGA dataset and differentially expressed AS (DEAS) events between tumor and paired normal BRCA tissues were identified. Enrichment analysis was then used to reveal the potential biological functions of DEAS events. We performed protein-protein interaction (PPI) analysis of DEAS events by using STRING and the correlation network between splicing factors (SFs) and AS events was constructed. The LASSO Cox model, Kaplan-Meier and log-rank tests were used to construct and evaluate DEAS-related risk signature, and the association between DEAS events and clinicopathological features were then analyzed.

Results

After strict filtering, 35,367 AS events and 973 DEAS events were detected. DEAS corresponding genes were significantly enriched in pivotal pathways including cell adhesion, cytoskeleton organization, and extracellular matrix organization. A total of 103 DEAS events were correlated with disease free survival. The DEAS-related risk signature stratified BRCA patients into two groups and the area under curve (AUC) was 0.754. Moreover, patients in the high-risk group had enriched basel-like subtype, advanced clinical stages, proliferation, and metastasis potency.

Conclusions

Collectively, the profile of DEAS landscape in BRCA revealed the potential biological function and prognostic value of DEAS events.

Autophagy deficiency promotes triple-negative breast cancer resistance to T cell-mediated cytotoxicity by blocking tenascin-C degradation

Most triple-negative breast cancer (TNBC) patients fail to respond to T cell-mediated immunotherapies. Unfortunately, the molecular determinants are still poorly understood. Breast cancer is the disease genetically linked to a deficiency in autophagy. Here, we show that autophagy defects in TNBC cells inhibit T cell-mediated tumour killing in vitro and in vivo. Mechanistically, we identify Tenascin-C as a candidate for autophagy deficiency-mediated immunosuppression, in which Tenascin-C is Lys63-ubiquitinated by Skp2, particularly at Lys942 and Lys1882, thus promoting its recognition by p62 and leading to its selective autophagic degradation. High Tenascin-C expression is associated with poor prognosis and inversely correlated with LC3B expression and CD8⁺ T cells in TNBC patients. More importantly, inhibition of Tenascin-C in autophagy-impaired TNBC cells sensitizes T cell-mediated tumour killing and improves antitumour effects of single anti-PD1/PDL1 therapy. Our results provide a potential strategy for targeting TNBC with the combination of Tenascin-C blockade and immune checkpoint inhibitors.

T cell mediated therapies have proven largely unsuccessful in triple-negative breast cancer (TNBC). Here, the authors show that autophagy is reduced in TNBC, which results in an increase in Tenascin C and reduced activation of tumour infiltrating lymphocytes.

Tumor suppressor genes and allele-specific expression: mechanisms and significance

Recent findings indicate that allele-specific expression (ASE) at specific cancer driver gene loci may be of importance in onset/progression of the disease. Of particular interest are loss-of-function (LOF) of tumor suppressor gene (TSGs) alleles. While LOF tumor suppressor mutations are typically considered to be recessive, if these mutant alleles can be significantly differentially expressed relative to wild-type alleles in heterozygotes, the clinical consequences could be significant. LOF TSG alleles are shown to be segregating at high frequencies in world-wide populations of normal/healthy individuals. Matched sets of normal and tumor tissues isolated from 233 cancer patients representing four diverse tumor types demonstrate functionally important changes in patterns of ASE in individuals heterozygous for LOF TSG alleles associated with cancer onset/progression. While a variety of molecular mechanisms were identified as potentially contributing to changes in ASE patterns in cancer, changes in DNA copy number and allele-specific alternative splicing possibly mediated by antisense RNA emerged as predominant factors. In conclusion, LOF TSGs are segregating in human populations at significant frequencies indicating that many otherwise healthy individuals are at elevated risk of developing cancer. Changes in ASE between normal and cancer tissues indicates that LOF TSG alleles may contribute to cancer onset/progression even when heterozygous with wild-type functional alleles.

Genomic alterations of Tenascin C in highly aggressive prostate cancer: a meta-analysis

Tenascin C (TNC), an extra-cellular matrix (ECM) family gene, is expressed in several cancer tissues of breast, lung, colon, and gastrointestinal tract leading to proliferation, migration, invasion, angiogenesis and metastasis, but its role in tumorigenesis of prostate cancer is poorly understood. We took a meta-analysis approach to characterize the alterations of TNC gene in prostate cancer using publicly available databases (cBioportal Version 2.2.0, http://www.cBioportal.org/index.do). The analysis identified TNC alterations (gene amplification) significantly in the neuroendocrine prostate cancer dataset (Trento/Broad/Cornell, N = 114), which was further validated in other prostate cancer datasets, including The Cancer Genome Atlas (TCGA) prostate cancer (2015). In the TCGA prostate cancer dataset (N = 498), high TNC (alteration frequency, 36%) revealed a strong association with high diagnostic Gleason score. Genomic alterations of TNC was also significantly associated (P < 0.05) with expression level of genes from NOTCH, SOX and WNT family, implicating a link between TNC and poorly differentiated aggressive phenotype in NEPC. TCGA prostate adenocarcinoma cases with TNC alteration also demonstrated prominent decrease in disease-free survival (P = 0.0637). These findings indicate a possible association of TNC to the aggressive subtype of prostate cancer and warrant further functional studies to evident the involvement of TNC in prostate cancer progression.

The role of matricellular proteins and tissue stiffness in breast cancer: a systematic review

Malignancies consist not only of cancerous and nonmalignant cells, but also of additional elements, as extracellular matrix. The aim of this review is to summarize meta-analyses, describing breast tissue stiffness and risk of breast carcinoma (BC) assessing the potential relationship between matricellular proteins (MPs) and survival. A systematic computer-based search of published articles, according to PRISMA statement, was conducted through Ovid interface. Mammographic density and tissue stiffness are associated with the risk of BC development, suggesting that MPs may influence BC prognosis. No definitive conclusions are available and additional researches are required to definitively clarify the role of each MP, mammographic density and stiffness in BC development and the mechanisms involved in the onset of this malignancy.

Desmoplastic Pattern at the Tumor Front Defines Poor-prognosis Subtypes of Colorectal Cancer

Although recent findings of cancer biology research indicate that prognostic power arises from genes expressed by stromal cells rather than epithelial cells, desmoplastic reaction (DR) has not been completely examined as a prognostic marker for colorectal cancer. A pathologic review of 821 stage II and III patients who underwent R0 resection for colorectal cancer at 4 independent institutions was conducted. DR was classified as mature, intermediate, or immature based on the existence of hyalinized keloid-like collagen and myxoid stroma at the extramural desmoplastic front. Totally, 325, 282, and 214 patients were classified as having mature, intermediate, and immature DR, respectively. DR significantly influenced the recurrence rate in the liver, lung, and peritoneum (P≤0.0001 to 0.01). Five-year relapse-free survival (RFS) rate was the highest in the mature group (85.7%), followed by the intermediate (77.3%) and immature (50.4%) groups. A significant adverse impact of immature stroma on RFS was observed in subset analyses of the 4 institutions. Multivariate analysis revealed that DR, along with T and N stages, is an independent prognostic factor. On the basis of Harrell's concordance index, the prognostic power of DR categorization (0.67) in stratifying RFS was greater than any other conventional prognostic factors, including TNM (0.64), N (0.62) and T stages (0.59), venous invasion (0.59), and tumor grade (0.54). Characterizing DR based on the histologic products of activated fibroblasts is valuable for evaluating prognostic outcomes. To our knowledge, this is the first study reporting a greater prognostic power of histology of the fibrotic stroma than that of tumor factors.

Silencing the roadblocks to effective triple-negative breast cancer treatments by siRNA nanoparticles

Over the past decade, RNA interference (RNAi) has been ubiquitously utilized to study biological function in vitro; however, limitations were associated with its utility in vivo More recently, small interfering RNA (siRNA) nanoparticles with improved biocompatibility have gained prevalence as a potential therapeutic option for the treatment of various diseases. The adaptability of siRNA nanoparticles enables the delivery of virtually any siRNA, which is especially advantageous for therapeutic applications in heterogeneous diseases that lack unifying molecular features, such as triple-negative breast cancer (TNBC). TNBC is an aggressive subtype of breast cancer that is stratified by the lack of estrogen receptor/progesterone receptor expression and HER2 amplification. There are currently no FDA-approved targeted therapies for the treatment of TNBCs, making cytotoxic chemotherapy the only treatment option available to these patients. In this review, we outline the current status of siRNA nanoparticles in clinical trials for cancer treatment and discuss the promising preclinical approaches that have utilized siRNA nanoparticles for TNBC treatment. Next, we address TNBC subtype-specific therapeutic interventions and highlight where and how siRNA nanoparticles fit into these strategies. Lastly, we point out ongoing challenges in the field of siRNA nanoparticle research that, if addressed, would significantly improve the efficacy of siRNA nanoparticles as a therapeutic option for cancer treatment.

CK2 Molecular Targeting-Tumor Cell-Specific Delivery of RNAi in Various Models of Cancer

Protein kinase CK2 demonstrates increased protein expression relative to non-transformed cells in the majority of cancers that have been examined. The elevated levels of CK2 are involved in promoting not only continued proliferation of cancer cells but also their resistance to cell death; thus, CK2 has emerged as a plausible target for cancer therapy. Our focus has been to target CK2 catalytic subunits at the molecular level using RNA interference (RNAi) strategies to achieve their downregulation. The delivery of oligonucleotide therapeutic agents warrants that they are protected and are delivered specifically to cancer cells. The latter is particularly important since CK2 is a ubiquitous signal that is essential for survival. To achieve these goals, we have developed a nanocapsule that has the properties of delivering an anti-CK2 RNAi therapeutic cargo, in a protected manner, specifically to cancer cells. Tenfibgen (TBG) is used as the ligand to target tenascin-C receptors, which are elevated in cancer cells. This strategy is effective for inhibiting growth and inducing death in several types of xenograft tumors, and the nanocapsule elicits no safety concerns in animals. Further investigation of this therapeutic approach for its translation is warranted.

Tenascin-C: Form versus function

Tenascin-C is a large, multimodular, extracellular matrix glycoprotein that exhibits a very restricted pattern of expression but an enormously diverse range of functions. Here, we discuss the importance of deciphering the expression pattern of, and effects mediated by, different forms of this molecule in order to fully understand tenascin-C biology. We focus on both post transcriptional and post translational events such as splicing, glycosylation, assembly into a 3D matrix and proteolytic cleavage, highlighting how these modifications are key to defining tenascin-C function.

Transcriptional regulation of tenascin genes

Extracellular matrix proteins of the tenascin family resemble each other in their domain structure, and also share functions in modulating cell adhesion and cellular responses to growth factors. Despite these common features, the 4 vertebrate tenascins exhibit vastly different expression patterns. Tenascin-R is specific to the central nervous system. Tenascin-C is an “oncofetal” protein controlled by many stimuli (growth factors, cytokines, mechanical stress), but with restricted occurrence in space and time. In contrast, tenascin-X is a constituitive component of connective tissues, and its level is barely affected by external factors. Finally, the expression of tenascin-W is similar to that of tenascin-C but even more limited. In accordance with their highly regulated expression, the promoters of the tenascin-C and -W genes contain TATA boxes, whereas those of the other 2 tenascins do not. This article summarizes what is currently known about the complex transcriptional regulation of the 4 tenascin genes in development and disease.

Preclinical evaluation of cyclin dependent kinase 11 and casein kinase 2 survival kinases as RNA interference targets for triple negative breast cancer therapy

Introduction

Targeted therapies for aggressive breast cancers like triple negative breast cancer (TNBC) are needed. The use of small interfering RNAs (siRNAs) to disable expression of survival genes provides a tool for killing these cancer cells. Cyclin dependent kinase 11 (CDK11) is a survival protein kinase that regulates RNA transcription, splicing and mitosis. Casein kinase 2 (CK2) is a survival protein kinase that suppresses cancer cell death. Eliminating the expression of these genes has potential therapeutic utility for breast cancer.

Methods

Expression levels of CDK11 and CK2 mRNAs and associated proteins were examined in breast cancer cell lines and tissue arrays. RNA expression levels of CDC2L1, CDC2L2, CCNL1, CCNL2, CSNK2A1, CSNK2A2, and CSNK2B genes in breast cancer subtypes were analyzed. Effects following transfection of siRNAs against CDK11 and CK2 in cultured cells were examined by viability and clonal survival assays and by RNA and protein measures. Uptake of tenfibgen (TBG) nanocapsules by TNBC cells was analyzed by fluorescence-activated cell sorting. TBG nanocapsules delivered siRNAs targeting CDK11 or CK2 in mice carrying TNBC xenograft tumors. Transcript cleavage and response parameters were evaluated.

Results

We found strong CDK11 and CK2 mRNA and protein expression in most human breast cancer cells. Immunohistochemical analysis of TNBC patient tissues showed 100% of tumors stained positive for CDK11 with high nuclear intensity compared to normal tissue. The Cancer Genome Atlas analysis comparing basal to other breast cancer subtypes and to normal breast revealed statistically significant differences. Down-regulation of CDK11 and/or CK2 in breast cancer cells caused significant loss of cell viability and clonal survival, reduced relevant mRNA and protein expression, and induced cell death changes. TBG nanocapsules were taken up by TNBC cells both in culture and in xenograft tumors. Treatment with TBG- siRNA to CDK11 or TBG- siRNA to CK2αα’ nanocapsules induced appropriate cleavage of CDK11 and CK2α transcripts in TNBC tumors, and caused MDA-MB-231 tumor reduction, loss of proliferation, and decreased expression of targeted genes.

Conclusions

CDK11 and CK2 expression are individually essential for breast cancer cell survival, including TNBC. These genes serve as promising new targets for therapeutic development in breast cancer.

Histologic categorization of desmoplastic reaction: its relevance to the colorectal cancer microenvironment and prognosis

BACKGROUND

Although the essential roles of stromata in tumor development have been recognized, the morphologic classification of desmoplastic reaction (DR) in colorectal cancer (CRC) is unclear.

METHODS

In this study, DRs were histologically classified into three patterns based on the products of activated fibroblasts (i.e., keloid-like collagen and myxoid stroma). The prognostic impact of DRs was evaluated in two independent cohorts of stages 2 and 3 CRC patients: cohort 1 (880 patients) and cohort 2 (474 patients). The association of DR and the local environment was investigated immunohistochemically.

RESULTS

In cohort 1, mature DR was shown by 413 patients, intermediate DR by 275 patients, and immature DR by 192 patients. Categorization of DR was significantly associated with tumor location, pT and pN stages, tumor differentiation, venous invasion, tumor budding, and Crohn's-like lymphoid reaction (P ≤ 0.0001-0.008). Immature DR was relevant to the high incidence of recurrence in the liver, lung, lymph nodes, peritoneum, and locoregional areas (P ≤ 0.0001-0.002). The 5-year disease-free survival rate was highest in the mature group (87 %), followed by the intermediate group (72 %) and the immature group (49 % (P < 0.0001). In the multivariate analysis, DR showed an impact on survival outcome independent of conventional prognostic factors, including pT and pN stages. These results were similarly observed in cohort 2. Immature DR was associated with normal MutL homologue 1 (MLH1)/MutS homologue 2 (MSH2) immunoreactivity, a smaller number of infiltrating CD8(+) T cells and tumor-associated macrophages, a decreased microvessel count, and positive expression of tenascin-C and fibronectin.

CONCLUSION

The proposed histologic DR categorization directly reflects tumor behavior in a modulating stromal environment and could provide valuable prognostic information for CRC patients.

Clinical significance of serum tenascin-c levels in epithelial ovarian cancer

Tenascin-C (TNC) is an extracellular matrix protein that is expressed at low levels in normal adult tissue but is highly expressed around many tumors including ovarian tumors. The objective of this study was to determine the clinical significance of the serum levels of TNC in epithelial ovarian cancer (EOC) patients. A total of 50 patients with a pathologically confirmed diagnosis of EOC were included in this study. Serum TNC levels were determined by the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) method. Age- and sex- matched 28 healthy controls were included in the analysis. Median age of the patients was 56.5 years old, range 22 to 83 years. Majority of the patients had advanced disease (FIGO stage III-IV) (90 %). The median serum TNC levels were found significantly higher in EOC patients (130.5 pg/mL) compared to healthy controls (90.1 pg/mL) (p = 0.03). We found no correlation between serum TNC levels and any prognostic parameters analyzed, including age of the patients, histology, tumor grade, stage of the disease, and response to chemotherapy. Survival analysis did not show statistically significant effect of serum TNC concentration on progression-free and overall survival (p = 0.36 and p = 0.19, respectively). However, patients with high serum TNC levels tend to have poor overall survival. In conclusion, although serum TNC levels are elevated, it has no predictive or prognostic roles on survival in EOC patients.

Clinical significance of serum tenascin-C levels in breast cancer

Tenascin-C (TNC) is a key molecule in tissue remodeling, and high levels are observed in many diseases, including heart failure, thrombosis, atherosclerosis, and cancer. High TNC expression by immunohistochemical analysis has been shown in invasive and metastasizing tissues from a variety of cancers, including colon, lung, brain, and breast. This study was conducted to investigate the serum level of TNC in breast cancer patients and its relationship with tumor progression and known prognostic parameters. Ninety-six breast cancer patients were enrolled into the study. Serum samples were obtained on first admission before adjuvant and metastatic treatments were given and at follow-up. Serum TNC levels were determined by the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) method. Median age of diagnosis was 48 years old (range, 29-80). Thirty-seven (39 %) patients had metastatic breast cancer. The mean TNC levels were found to be significantly higher in patients with breast cancer (344.1 ± 42.4 pg/mL) compared to those in healthy controls (137.2 ± 26.8 pg/mL) (p = 0.005). Serum TNC level in grade 3 tumors was found to be significantly higher than in grades 1-2 tumors (p = 0.04). No correlation was detected between serum TNC levels and other prognostic parameters analyzed, including presence of metastasis, lymph node involvement, and tumor size. Serum TNC level had no significantly adverse effect on survival in univariate and multivariate analyses (p = 0.65 and p = 0.85, respectively). In conclusion, although serum TNC levels are elevated, it has no predictive or prognostic roles on survival in breast cancer patients.

Comprehensive analysis of transcriptome variation uncovers known and novel driver events in T-cell acute lymphoblastic leukemia

RNA-seq is a promising technology to re-sequence protein coding genes for the identification of single nucleotide variants (SNV), while simultaneously obtaining information on structural variations and gene expression perturbations. We asked whether RNA-seq is suitable for the detection of driver mutations in T-cell acute lymphoblastic leukemia (T-ALL). These leukemias are caused by a combination of gene fusions, over-expression of transcription factors and cooperative point mutations in oncogenes and tumor suppressor genes. We analyzed 31 T-ALL patient samples and 18 T-ALL cell lines by high-coverage paired-end RNA-seq. First, we optimized the detection of SNVs in RNA-seq data by comparing the results with exome re-sequencing data. We identified known driver genes with recurrent protein altering variations, as well as several new candidates including H3F3A, PTK2B, and STAT5B. Next, we determined accurate gene expression levels from the RNA-seq data through normalizations and batch effect removal, and used these to classify patients into T-ALL subtypes. Finally, we detected gene fusions, of which several can explain the over-expression of key driver genes such as TLX1, PLAG1, LMO1, or NKX2-1; and others result in novel fusion transcripts encoding activated kinases (SSBP2-FER and TPM3-JAK2) or involving MLLT10. In conclusion, we present novel analysis pipelines for variant calling, variant filtering, and expression normalization on RNA-seq data, and successfully applied these for the detection of translocations, point mutations, INDELs, exon-skipping events, and expression perturbations in T-ALL.

The quest for somatic mutations underlying oncogenic processes is a central theme in today's cancer research. High-throughput genomics approaches including amplicon re-sequencing, exome re-sequencing, full genome re-sequencing, and SNP arrays have contributed to cataloguing driver genes across cancer types. Thus far transcriptome sequencing by RNA-seq has been mainly used for the detection of fusion genes, while few studies have assessed its value for the combined detection of SNPs, INDELs, fusions, gene expression changes, and alternative transcript events. Here we apply RNA-seq to 49 T-ALL samples and perform a critical assessment of the bioinformatics pipelines and filters to identify each type of aberration. By comparing to exome re-sequencing, and by exploiting the catalogues of known cancer drivers, we identified many known and several novel driver genes in T-ALL. We also determined an optimal normalization strategy to obtain accurate gene expression levels and used these to identify over-expressed transcription factors that characterize different T-ALL subtypes. Finally, by PCR, cloning, and in vitro cellular assays we uncover new fusion genes that have consequences at the level of gene expression, oncogenic chimaeras, and tumor suppressor inactivation. In conclusion, we present the first RNA-seq data set across T-ALL patients and identify new driver events.

RNA sequencing of cancer reveals novel splicing alterations

Breast cancer transcriptome acquires a myriad of regulation changes, and splicing is critical for the cell to “tailor-make” specific functional transcripts. We systematically revealed splicing signatures of the three most common types of breast tumors using RNA sequencing: TNBC, non-TNBC and HER2-positive breast cancer. We discovered subtype specific differentially spliced genes and splice isoforms not previously recognized in human transcriptome. Further, we showed that exon skip and intron retention are predominant splice events in breast cancer. In addition, we found that differential expression of primary transcripts and promoter switching are significantly deregulated in breast cancer compared to normal breast. We validated the presence of novel hybrid isoforms of critical molecules like CDK4, LARP1, ADD3, and PHLPP2. Our study provides the first comprehensive portrait of transcriptional and splicing signatures specific to breast cancer sub-types, as well as previously unknown transcripts that prompt the need for complete annotation of tissue and disease specific transcriptome.

Microenvironment for cancer stem cells

Cancer stem cells and their metastatic niche are one of hot topics for tumor study. This review introduces the definition of microenvironment (niche) for cancer stem cells, related cells and factors, characteristics and regulation of niche, premetastatic niche and tissue components. The research progress in this field can provide some clues to the metastatic mechanism of tumors and the development and improvement of chemotherapeutic drugs.

Breast tumor and stromal cell responses to TGF-β and hypoxia in matrix deposition

The components that comprise the extracellular matrix (ECM) are integral to normal tissue homeostasis as well as the development and progression of breast tumors. The secretion, construction, and remodeling of the ECM are each regulated by a complex interplay between tumor cells, fibroblasts and macrophages. Transforming growth factor-β (TGF-β) is an essential molecule in regulating the cellular production of ECM molecules and the adhesive interactions of cells with the ECM. Additionally, hypoxic cell signals, initiated by oxygen deprivation, additional metabolic factors or receptor activation, are associated with ECM formation and the progression of breast cancer. Both TGF-β and hypoxic cell signals are implicated in the functional and morphological changes of cancer-associated-fibroblasts and tumor-associated-macrophages. Moreover, the enhanced recruitment of tumor and stromal cells in response to hypoxia-induced chemokines leads to increased ECM deposition and remodeling, increased blood vessel formation, and enhanced tumor migration. Thus, elucidation of the collaborative networks between tumor and stromal cells in response to the combined signals of TGF-β and hypoxia may yield insight into treatment parameters that target both tumor and stromal cells.

Comparability of differential proteomics data generated from paired archival fresh-frozen and formalin-fixed samples by GeLC-MS/MS and spectral counting

In this study, a Veterinary Department repository composed by paired formalin-fixed paraffin-embedded (FFPE) and fresh-frozen (FrFr) sets of the same tissues, routinely archived in the typical conditions of a clinical setting, was exploited to perform a comparative evaluation of the results generated by GeLC-MS/MS (1-DE followed by in-gel digestion and LC-MS/MS) and spectral counting with the two types of archival samples. Therefore, two parallel differential proteomic studies were performed using 3 canine mammary carcinomas and 3 normal controls in a paired fashion (6 FrFr and 6 FFPE in total). As a result, the FrFr and FFPE differential proteomic datasets exhibited fair consistency in differential expression trends, according to protein molecular function, cellular localization, networks, and pathways. However, FFPE samples were globally slightly less informative, especially concerning the high-MW subproteome. As a further investigation, new insights into the molecular aspects of protein fixation and retrieval were obtained. In conclusion, archival FFPE samples can be reliably used for differential proteomics studies employing a spectral counting GeLC-MS/MS approach, although some typical biases need to be taken into account, and FrFr specimens (when available) should still be considered as the gold standard for clinical proteomics.

Early detection of lung cancer by molecular markers in endobronchial epithelial-lining fluid

INTRODUCTION

Early detection of malignancies in the lung by less-invasive methods aims at achieving efficient intervention and subsequently a reduction of the high mortality rate. We investigated whether biomarker analysis in endobronchial epithelial-lining fluid (ELF) collected by bronchoscopic microsampling (BMS) may be useful for a definitive preoperative diagnosis.

METHODS

ELF was collected from subsegmental bronchi close to the indeterminate pulmonary nodule, which was detected by computed tomography, and from the contralateral lung. Diagnosis was confirmed by transbronchial biopsy or surgery. The study includes 142 ELF samples from 51 non-small-cell lung cancer patients and 20 benign cases. Microarray analysis was done with a patient subset (n = 15) to narrow down genes associated with a malignant phenotype. Thirteen potential biomarkers have been further analyzed by quantitative real-time polymerases chain reaction in an independent patient cohort (n = 56).

RESULTS

All patients underwent BMS without complications. Gene-expression analyses by microarrays and quantitative real-time polymerases chain reaction could be reliably applied to ELF samples, and resulted in potential biomarkers for malignant pulmonary nodules. Four genes (tenascin-C, [C-X-C motif] ligand 14, S100 calcium binding protein A9, and keratin 17) were found to be upregulated in ELF of non-small-cell lung cancer patients with adenocarcinoma or squamous cell carcinoma. Combined analysis of tenascin-C expression and the nodule size improved the prediction of malignancy in this patient cohort.

CONCLUSIONS

Our study suggests that the analysis of specific biomarkers in ELF collected by BMS could be a potentially useful adjunct to other diagnostic techniques aiming at the preoperative diagnosis of malignant pulmonary nodules.

Tenascin-W is a better cancer biomarker than tenascin-C for most human solid tumors

Background

Tenascins are large glycoproteins found in the extracellular matrix of many embryonic and adult tissues. Tenascin-C is a well-studied biomarker known for its high overexpression in the stroma of most solid cancers. Tenascin-W, the least studied member of the family, is highly expressed in the stroma of colon and breast tumors and in gliomas, but not in the corresponding normal tissues. Other solid tumors have not been analyzed. The present study was undertaken to determine whether tenascin-W could serve as a cancer-specific extracellular matrix protein in a broad range of solid tumors.

Methods

We analyzed the expression of tenascin-W and tenascin-C by immunoblotting and by immunohistochemistry on multiple frozen tissue microarrays of carcinomas of the pancreas, kidney and lung as well as melanomas and compared them to healthy tissues.

Results

From all healthy adult organs tested, only liver and spleen showed detectable levels of tenascin-W, suggesting that tenascin-W is absent from most human adult organs under normal, non-pathological conditions. In contrast, tenascin-W was detectable in the majority of melanomas and their metastases, as well as in pancreas, kidney, and lung carcinomas. Comparing lung tumor samples and matching control tissues for each patient revealed a clear overexpression of tenascin-W in tumor tissues. Although the number of samples examined is too small to draw statistically significant conclusions, there seems to be a tendency for increased tenascin-W expression in higher grade tumors. Interestingly, in most tumor types, tenascin-W is also expressed in close proximity to blood vessels, as shown by CD31 co-staining of the samples.

Conclusions

The present study extends the tumor biomarker potential of tenascin-W to a broad range of solid tumors and shows its accessibility from the blood stream for potential therapeutic strategies.

Why the stroma matters in breast cancer: insights into breast cancer patient outcomes through the examination of stromal biomarkers

Survival and recurrence rates in breast cancer are variable for common diagnoses, and therefore the biological underpinnings of the disease that determine those outcomes are yet to be fully understood. As a result, translational medicine is one of the fastest growing arenas of study in tumor biology. With advancements in genetic and imaging techniques, archived biopsies can be examined for purposes other than diagnosis. There is a great deal of evidence that points to the stroma as the major regulator of tumor progression following the initial stages of tumor formation, and the stroma may also contribute to risk factors determining tumor formation. Therefore, aspects of stromal biology are well-suited to be a focus for studies of patient outcome, where statistical differences in survival among patients provide evidence as to whether that stromal component is a signpost for tumor progression. In this review we summarize the latest research done where breast cancer patient survival was correlated with aspects of stromal biology, which have been put into four categories: reorganization of the extracellular matrix (ECM) to promote invasion, changes in the expression of stromal cell types, changes in stromal gene expression, and changes in cell biology signaling cascades to and from the stroma.

A heterogeneous in vitro three dimensional model of tumour-stroma interactions regulating sprouting angiogenesis

Angiogenesis, the formation of new blood vessels, is an essential process for tumour progression and is an area of significant therapeutic interest. Different in vitro systems and more complex in vivo systems have been described for the study of tumour angiogenesis. However, there are few human 3D in vitro systems described to date which mimic the cellular heterogeneity and complexity of angiogenesis within the tumour microenvironment. In this study we describe the Minitumour model--a 3 dimensional human spheroid-based system consisting of endothelial cells and fibroblasts in co-culture with the breast cancer cell line MDA-MB-231, for the study of tumour angiogenesis in vitro. After implantation in collagen-I gels, Minitumour spheroids form quantifiable endothelial capillary-like structures. The endothelial cell pre-capillary sprouts are supported by the fibroblasts, which act as mural cells, and their growth is increased by the presence of cancer cells. Characterisation of the Minitumour model using small molecule inhibitors and inhibitory antibodies show that endothelial sprout formation is dependent on growth factors and cytokines known to be important for tumour angiogenesis. The model also shows a response to anti-angiogenic agents similar to previously described in vivo data. We demonstrate that independent manipulation of the different cell types is possible, using common molecular techniques, before incorporation into the model. This aspect of Minitumour spheroid analysis makes this model ideal for high content studies of gene function in individual cell types, allowing for the dissection of their roles in cell-cell interactions. Finally, using this technique, we were able to show the requirement of the metalloproteinase MT1-MMP in endothelial cells and fibroblasts, but not cancer cells, for sprouting angiogenesis.

Matrikines and the lungs

The extracellular matrix is a complex network of fibrous and nonfibrous molecules that not only provide structure to the lung but also interact with and regulate the behaviour of the cells which it surrounds. Recently it has been recognised that components of the extracellular matrix proteins are released, often through the action of endogenous proteases, and these fragments are termed matrikines. Matrikines have biological activities, independent of their role within the extracellular matrix structure, which may play important roles in the lung in health and disease pathology. Integrins are the primary cell surface receptors, characterised to date, which are used by the matrikines to exert their effects on cells. However, evidence is emerging for the need for co-factors and other receptors for the matrikines to exert their effects on cells. The potential for matrikines, and peptides derived from these extracellular matrix protein fragments, as therapeutic agents has recently been recognised. The natural role of these matrikines (including inhibitors of angiogenesis and possibly inflammation) make them ideal targets to mimic as therapies. A number of these peptides have been taken forward into clinical trials. The focus of this review will be to summarise our current understanding of the role, and potential for highly relevant actions, of matrikines in lung health and disease.

Targeting tumor cell motility to prevent metastasis

Mortality and morbidity in patients with solid tumors invariably result from the disruption of normal biological function caused by disseminating tumor cells. Tumor cell migration is under intense investigation as the underlying cause of cancer metastasis. The need for tumor cell motility in the progression of metastasis has been established experimentally and is supported empirically by basic and clinical research implicating a large collection of migration-related genes. However, there are few clinical interventions designed to specifically target the motility of tumor cells and adjuvant therapy to specifically prevent cancer cell dissemination is severely limited. In an attempt to define motility targets suitable for treating metastasis, we have parsed the molecular determinants of tumor cell motility into five underlying principles including cell autonomous ability, soluble communication, cell-cell adhesion, cell-matrix adhesion, and integrating these determinants of migration on molecular scaffolds. The current challenge is to implement meaningful and sustainable inhibition of metastasis by developing clinically viable disruption of molecular targets that control these fundamental capabilities.

B domain containing Tenascin-C: a new urine marker for surveillance of patients with urothelial carcinoma of the urinary bladder?

BACKGROUND

ECM remodelling during tumorigenesis entails the re-occurrence of different Tn-C(L) splicing variants. In patients with urothelial carcinoma of the urinary bladder (UBC), B and C domain containing Tenascin-C (B(+) and C(+) Tn-C) urine levels were shown to be increased in case of muscle invasiveness. Thus, the present study was aimed at examining the ability of B(+) and C(+) Tn-C as potential urinary surveillance markers of UBC patients.

METHODS

Urine levels of B(+) and C(+) Tn-C were determined by ELISA in 35 UBC patients during a 2 year follow-up period after therapy and related to clinical diagnosis and histological stage in 4 defined groups representing typical courses of disease.

RESULTS

B(+) Tn-C levels showed significant differences between cases of tumour progression or regression. The urine levels of B(+) Tn-C could be used to discriminate between cases without tumour recurrence and such with tumour existence (cut-off value: 0.8 ng/ml) or between non-muscle invasive and muscle invasive tumour growth (cut-off value: 3.5 ng/ml).

CONCLUSIONS

Progression of UBC with time is accompanied by significant changes in urinary levels of B(+) Tn-C. Urinary B(+) Tn-C can therefore be suggested as a valuable urine surveillance marker in UBC follow-up care.