Novel surface targets and serum biomarkers from the ovarian cancer vasculature

Identification of RNF213 as a Potential Suppressor of Local Invasion in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a lethal cancer with poor survival especially when it spreads. The histopathology of its rare intraductal papillary neoplasm of the bile duct type (IPNB) characteristically shows cancer cells originating within the confined bile duct space. These cells eventually invade and infiltrate the nearby liver tissues, making it a good model to study the mechanism of local invasion, which is the earliest step of metastasis. To discover potential suppressor genes of local invasion in ICC, we analyzed the somatic mutation profiles and performed clonal evolution analyses of the 11 pairs of macrodissected locally invasive IPNB tissues (LI-IPNB) and IPNB tissues without local invasion from the same patients. We identified a protein-truncating variant in an E3 ubiquitin ligase, RNF213 (c.6967C>T; p.Gln2323X; chr17: 78,319,102 [hg19], exon 29), as the most common protein-truncating variant event in LI-IPNB samples (4/11 patients). Knockdown of RNF213 in HuCCT1 and YSCCC cells showed increased migration and invasion, and reduced vasculogenic mimicry but maintained normal proliferation. Transcriptomic analysis of the RNF213-knockdown vs control cells was then performed in the HuCCT1, YSCCC, and KKU-100 cells. Gene ontology enrichment analysis of the common differentially expressed genes revealed significantly altered cytokine and oxidoreductase-oxidizing metal ion activities, as confirmed by Western blotting. Gene Set Enrichment Analysis identified the most enriched pathways being oxidative phosphorylation, fatty acid metabolism, reactive oxygen species, adipogenesis, and angiogenesis. In sum, loss-of-function mutation of RNF213 is a common genetic alteration in LI-IPNB tissues. RNF213 knockdown leads to increased migration and invasion of ICC cells, potentially through malfunctions of the pathways related to inflammation and energy metabolisms.

A Structural and Functional Perspective of Death Receptor 6

As a member of the tumor necrosis factor receptor superfamily (TNFRSF), death receptor 6 (DR6) has a similar structural architecture to other family members. The extracellular region of DR6 contains four cysteine-rich domains, followed by a single-pass transmembrane domain and an intracellular region. Since its discovery, DR6 has become an orphan receptor ubiquitously expressed to transduce unique signaling pathways. Although the free ectodomains of β-amyloid precursor protein (APP) can bind to DR6 to induce apoptotic signals, the natural ligands of DR6 still remain largely unknown. In this review, we focus on recent research progress of structural and functional studies on DR6 for better understanding DR6-mediated signaling and the treatment of DR6-related diseases.

Comprehensive Analysis and Identification of Prognostic Biomarkers and Therapeutic Targets Among FAM83 Family Members for Gastric Cancer

Background: Gastric cancer (GC) is one of the most common and poor prognosis malignancy in the world. The Family with sequence similarity 83 (FAM83) comprises of eight members of A–H. Accumulating evidence confirmed important roles for FAM83 family in tumorigenesis and progression. However, the prognostic values of FAM83 family in GC still have not been clarified.

Methods: ONCOMINE, UALCAN, GEPIA, THE HUMAN PROTEIN ATLAS, Kaplan–Meier Plotter, cBioPortal, DAVID, STRING and TIMER databases and R software were adopted in this study.

Results: In this study, we demonstrated that the mRNA levels of FAM83 B/C/D/H were significantly up-regulated in stomach adenocarcinoma (STAD), but the protein level of FAM83G/H were remarkable lowly in STAD. Next, FAM83C/D/G/H were significantly associated with tumor stages in STAD patients. Then, the mutation rate of FAM83 family members in STAD patients was 46%, and the highest mutation rate was FAM83H (23%). Furthermore, the functions of FAM83 family and their 259 co-expression genes were primarily related to Shigellosis, RNA degradation and Ribosome biogenesis in eukaryotes pathway. Besides, we have established the prognostic model of FAM83 family in STAD, including the prognostic model of STAD patients (FAM83C/D/G), STAD with lymph node metastasis (FAM83C/D/G/H) and STAD with ERBB2 high expression (FAM83G/H). FAM83C/D high expression with a poor prognosis, while FAM83G/H high expression with a favorable prognosis of STAD. Additionally, we found that the expression of FAM83C/D/G/H were significantly correlated with the infiltration of six types of immune cells [B cells, CD8⁺T cells, CD4⁺T cells, macrophages and Myeloid dendritic cells (DC)], whereas CD4⁺T cells and Macrophage cells have higher risk scores (HR > 1) when FAM83C lowly expression and FAM83D highly expression. The risk score of NK cells was significantly reduced when FAM83G lowly expression and FAM83H highly expression (HR < 1).

Conclusion: These findings suggested that FAM83C/D/G/H might play key roles in STAD tumorigenesis and progression, and FAM83C/D might be risk factors but FAM83G/H might be favorable prognostic factors for STAD patients. In addition, CD4⁺T cells and Macrophage cells may be the promoters of FAM83D in progression of STAD, while NK cells may promote the protective effect of FAM83H on STAD patients.

A Review of Principal Studies on the Development and Treatment of Epithelial Ovarian Cancer in the Laying Hen Gallus gallus

Often referred to as the silent killer, ovarian cancer is the most lethal gynecologic malignancy. This disease rarely shows any physical symptoms until late stages and no known biomarkers are available for early detection. Because ovarian cancer is rarely detected early, the physiology behind the initiation, progression, treatment, and prevention of this disease remains largely unclear. Over the past 2 decades, the laying hen has emerged as a model that naturally develops epithelial ovarian cancer that is both pathologically and histologically similar to that of the human form of the disease. Different molecular signatures found in human ovarian cancer have also been identified in chicken ovarian cancer including increased CA125 and elevated E-cadherin expression, among others. Chemoprevention studies conducted in this model have shown that decreased ovulation and inflammation are associated with decreased incidence of ovarian cancer development. The purpose of this article is to review the major studies performed in laying hen model of ovarian cancer and discuss how these studies shape our current understanding of the pathophysiology, prevention, and treatment of epithelial ovarian cancer.

FAM83H and SCRIB stabilize β-catenin and stimulate progression of gastric carcinoma

FAM83H primarily is known for its function in tooth development. Recently, a role for FAM83H in tumorigenesis, conjunction with MYC and β-catenin, has been suggested. Analysis of public data indicates that FAM83H expression is closely associated with SCRIB expression in human gastric cancers. Therefore, this study investigated the roles of FAM83H and SCRIB in 200 human gastric cancers and gastric cancer cells. In human gastric carcinomas, both the individual and combined expression patterns of the nuclear FAM83H and SCRIB were independent indicators of shorter survival of gastric carcinoma patients. In MKN-45 and NCI-N87 gastric cancer cells, the expression of FAM83H and SCRIB were associated with proliferation and invasiveness of cells. FAM83H-mediated in vivo tumor growth was attenuated with knock-down of SCRIB. Moreover, immunoprecipitation indicates that FAM83H, SCRIB, and β-catenin, form a complex, and knock-down of either FAM83H or SCRIB accelerated proteasomal degradation of β-catenin. In conclusion, this study has found that the individual and combined expression patterns of nuclear FAM83H and SCRIB are prognostic indicators of gastric carcinomas and further suggests that FAM83H and SCRIB are involved in the progression of gastric carcinomas by stabilizing β-catenin.

miR-6086 inhibits ovarian cancer angiogenesis by downregulating the OC2/VEGFA/EGFL6 axis

miRNAs have emerged as a pivotal component of gene regulatory networks, mediating cytokines secretion, cell cycle, and differentiation regulation. However, how miRNAs collaborate with transcription factors and downstream effector proteins that determine the fate of ovarian cancer cells remains to be understood, especially regarding to mechanism of tumor angiogenesis regulation. Based on the qRT-PCR and IHC analysis, we found that miR-6086 was maintained a very low level both in ovarian cancer cell lines and tissues. Further, we identified OC2 and EGFL6 as the direct targets of miR-6086 by luciferase assay and we observed an inverse relationship between the expression of miR-6086 and the OC2/VEGFA/EGFL6 axis. The Western blotting analysis suggested that OC2 could directly upregulate VEGFA and indirectly up-regulate EGFL6 through VEGFA. Moreover, miR-6086 could indirectly downregulate VEGFA through OC2. In addition, miR-6086, siOC2 and siEGFL6 could negatively regulate the tumor growth and angiogenesis of ovarian cancer (Skov3) in the animal studies, with the inhibition rates of 77.07%, 69.89%, and 73.62%, respectively (**p < 0.01). Moreover, the tumor cell proliferation, migration, and invasion of ovarian cancer cell lines (Caov3 and Skov3) and vascular formation (HUVECs) were significantly suppressed in vitro, by decreasing the AKT/MAPK pathways (*p < 0.05). Taken together, our results reveal that miR-6086 can suppress the angiogenesis networks in ovarian cancer by down-regulating the OC2/VEGFA/EGFL6 axis, directly or indirectly, which may provide potential targets for tumor therapeutics.

FAM83H is involved in stabilization of β-catenin and progression of osteosarcomas

Background

FAM83H was initially identified as a protein essential for dental enamel formation. Recent reports have shown that FAM83H is also involved in the progression of human cancers in conjunction with tumor-associated molecules, such as MYC and β-catenin. However, the role of FAM83H in sarcoma has not yet been investigated.

Methods

The expression and roles of FAM83H and β-catenin were evaluated in human osteosarcomas from 34 patients and osteosarcoma cells.

Results

The expression of nuclear FAM83H, cytoplasmic FAM83H, and β-catenin were significantly associated with each other and significantly associated with shorter survival of osteosarcoma patients by univariate analysis. In multivariate analysis, cytoplasmic expression of FAM83H was an independent indicator of shorter survival of osteosarcoma patients (overall survival; P <  0.001, relapse-free survival; P <  0.001). In U2OS, MG63, and KHOS/NP osteosarcoma cells, the knock-down of FAM83H decreased proliferation and invasion activity and overexpression of FAM83H increased proliferation and invasion activity. In KHOS/NP cells, knock-down of FAM83H significantly inhibited, and overexpression of FAM83H significantly increased in vivo growth of cells. In addition, the knock-down of FAM83H decreased protein expression of β-catenin, active β-catenin, cyclin D1, vimentin, and snail. Overexpression of FAM83H increased protein expression of β-catenin, active β-catenin, cyclin D1, vimentin, and snail. However, the expression of β-catenin mRNA was not significantly altered with knock-down or overexpression of FAM83H. In addition, FAM83H and β-catenin shown to directly interact via immunoprecipitation and nuclear and cytoplasmic localization of β-catenin was decreased with knock-down of FAM83H. Moreover, the ubiquitination and proteasomal degradation of β-catenin was increased with knock-down of FAM83H.

Conclusions

This study suggests that FAM83H is involved in the progression of osteosarcomas via a mechanism involving the stabilization of β-catenin and the promotion of proliferation and invasiveness of osteosarcomas.

Serum biomarker panels for the diagnosis of gastric cancer

Gastric cancer is a leading cause of mortality due to neoplastic disease. Although early detection of gastric cancers can decrease the mortality rate, it remains a diagnostic challenge because of the lack of effective biomarkers. In this study, fifteen gastric cancer patients and ten healthy subjects were recruited to assess novel serum biomarkers for gastric cancer using antibody microarray technology. ELISA was utilized to validate the antibody array results. As a result, compared to the controls, eleven cytokines were found to be significantly increased in gastric cancer, including interferon gamma receptor 1 (IFNGR1), neurogenic locus notch homolog protein 3 (Notch‐3), tumor necrosis factor receptor superfamily member 19L (TNFRSF19L), growth hormone receptor (GHR), signaling lymphocytic activation molecule family 8 (SLAMF8), folate receptor beta (FR‐beta), integrin alpha 5, galectin‐8, erythropoietin‐producing hepatocellular A1 (EphA1), epiregulin, and fibroblast growth factor 12 (FGF‐12) with P < 0.05. ELISA validation supported the results of the antibody array. More importantly, most of these eleven cytokines, including IFNGR1, TNFRSF19L, GHR, SLAMF8, FR‐beta, and integrin alpha 5 were discovered to be elevated in gastric cancer serum samples for the first time in this study, suggesting that these proteins may serve as novel biomarkers for the early diagnosis and prognosis determination of gastric cancer.

Death receptor 6 promotes ovarian cancer cell migration through KIF11

The expression of death receptor 6 (DR6) is abnormal in some cancer types, but the function and underlying molecular mechanisms of DR6 in tumor progression are not yet clear. In the present study, our analysis of ovarian cancer RNA sequencing data from The Cancer Genome Atlas revealed that DR6 is upregulated in human ovarian cancer. We confirmed that the expression level of DR6 is upregulated in ovarian cancer tissues when compared with matched adjacent normal tissues. In addition, DR6 enhanced ovarian carcinoma cell migration ability, and decreased expression of DR6 inhibited the expression of matrix metalloprotease (MMP) 2 and MMP9, and increased the expression of E‐cadherin. Additionally, DR6 shRNA caused a significant decrease in phosphoinositide‐3‐kinase (PI3K), phospho (p) ‐AKT, p‐extracellular signal‐regulated kinase (ERK), and p‐mitogen‐activated protein kinase kinase expression in SKOV3 cells. These results suggested that DR6 can enhance ovarian carcinoma cell migration ability through the mitogen‐activated protein kinase/ERK and PI3K/AKT pathways. Notably, mass spectrometric analysis indicated that DR6 co‐purified with kinesin family member 11 (KIF11), and we verified the interaction between KIF11 and DR6 by co‐immunoprecipitation and glutathione S‐transferase pull‐down. Furthermore, we demonstrated that DR6 can bind tumor necrosis factor receptor‐associated factor 4 (TRAF4) with co‐immunoprecipitation. Overexpression of KIF11 or TRAF4 eliminated the suppression of carcinoma cell migration by DR6 knockdown. We also found that TRAF4 and KIF11 were upregulated in ovarian carcinomas and that their level of expression was positively correlated with that of DR6. The findings above suggest that DR6 may play a notable oncogenic role in ovarian malignancy by interacting with TRAF4 and KIF11, and that DR6 may be an effective therapeutic target in ovarian cancer.

Identification and validation of differentially expressed proteins in epithelial ovarian cancers using quantitative proteomics

Ovarian cancer is the most lethal gynecological malignant tumor because of its high recurrence rate. In the present work, in order to find new therapeutic targets, we identified 8480 proteins in thirteen pairs of ovarian cancer tissues and normal ovary tissues through quantitative proteomics. 498 proteins were found to be differentially expressed in ovarian cancer, which involved in various cellular processes, including metabolism, response to stimulus and biosynthetic process. The expression levels of chloride intracellular channel protein 1 (CLIC1) and lectin galactoside-binding soluble 3 binding protein (LGALS3BP) in epithelial ovarian cancer tissues were significantly higher than those in normal ovary tissues as confirmed by western blotting and immunohistochemistry. The knockdown of CLIC1 in A2780 cell line downregulated expression of CTPS1, leading to the decrease of CTP and an arrest of cell cycle G1 phase, which results into a slower proliferation. CLIC1-knockdown can also slow down the tumor growth in vivo. Besides, CLIC1-knockdown cells showed an increased sensitivity to hydrogen peroxide and cisplatin, suggesting that CLIC1 was involved in regulation of redox and drug resistance in ovarian cancer cells. These results indicate CLIC1 promotes tumorgenesis, and is a potential therapeutic target in epithelial ovarian cancer treatment.

Enhancement of Ovarian Tumor Detection by DR6-Targeted Ultrasound Imaging Agents in Laying Hen Model of Spontaneous Ovarian Cancer

OBJECTIVE

The lack of an effective early detection test leads to high case to death ratio of women with ovarian cancer (OVCA). To improve early detection, tumor-associated imaging targets need to be established and imaging agents to image these targets need to be developed. Targeted imaging agents offer potential for improvement of signal intensities from their targets. Expression of death receptor 6 (DR6) by ovarian malignant cells and tumor-associated microvessels increases during OVCA development and represents a novel target for ultrasound imaging. The goal of this study was to examine the feasibility of newly developed DR6-targeted ultrasound imaging agents in enhancing early detection of ovarian tumors in laying hen model of spontaneous OVCA.

MATERIALS AND METHODS

The study was conducted in an exploratory cross-sectional design using 4-year-old laying hens (n = 130). DR6-targeted imaging agents were developed by conjugating microbubbles with rabbit anti-chicken DR6 antibodies. Changes in signal intensity of ultrasound imaging were determined before and after injection of targeted imaging agents in hens with or without spontaneous OVCA. Following targeted imaging, normal or tumor ovaries were processed for histopathological and immunohistochemical studies.

RESULTS

DR6-targeted imaging agents bound with their targets expressed by malignant cells and tumor-associated microvessels in the ovary. Compared with pretargeted imaging, targeted imaging is enhanced by approximately 40% ultrasound echo signal intensity (P < 0.001) from early- and late-stage OVCA. Differences in signal enhancement were not observed among different histological subtypes of OVCA at early or late stages. Higher imaging signal intensities were associated with enhancement in DR6 expression by ovarian malignant cells and increase in the frequency of DR6-expressing microvessels during OVCA development.

CONCLUSIONS

The results of this study suggest that DR6-targeted imaging agents enhance the visualization of ovarian tumors and tumor-associated microvessels in hens with early-stage OVCA and will form a foundation for clinical studies.

ADAM12 Is a Novel Regulator of Tumor Angiogenesis via STAT3 Signaling

ADAM12, (ADisintegrin and metalloproteinase domain-containing protein 12), is upregulated in epithelial cancers and contributes to increased tumor proliferation, metastasis, and endocrine resistance. However, its role in tumor angiogenesis is unknown. Here, we report that ADAM12 is upregulated in the vessels of aggressive breast tumors and exerts key regulatory functions. ADAM12 significantly increases bFGF-mediated angiogenesis in vivo and ADAM12 levels are upregulated in tumors that have undergone a switch to the angiogenic phenotype. Importantly, ADAM12-overexpressing breast tumors display a higher microvessel density (MVD). Our goal was to identify the mechanisms by which tumor-associated ADAM12 promotes angiogenesis. ADAM12 expression in breast tumor cells correlated with a significant upregulation of proangiogenic factors such as VEGF and MMP-9 and downregulation of antiangiogenic factors such as Thrombospondin-1 (THBS1/TSP1) and Tissue Inhibitor of Metalloproteinases-2 (TIMP-2). Co-culture with ADAM12-expressing tumor cells promoted endothelial cell (EC) recruitment and capillary tube formation. Conversely, downregulation of endogenous ADAM12 in breast cancer cell lines resulted in reduction of pro-angiogenic factors and EC recruitment. These ADAM12-mediated effects are driven by the activation of EGFR, STAT3 and Akt signaling. Blockade of EGFR/STAT3 or silencing of ADAM12 reversed the proangiogenic tumor phenotype, significantly downregulated pro-angiogenic mitogens and reduced EC recruitment. In human breast cancer tissues, ADAM12 expression was significantly positively correlated with pro-angiogenic factors including VEGF and MMP-9 but negatively associated with TSP1.Implications: These novel findings suggest that ADAM12 regulates EC function and facilitates a proangiogenic microenvironment in a STAT3-dependent manner. A combined approach of targeting ADAM12 and STAT3 signaling in breast cancer may represent a promising strategy to inhibit tumor neovascularization. Mol Cancer Res; 15(11); 1608-22. ©2017 AACR.

FAM83H is involved in the progression of hepatocellular carcinoma and is regulated by MYC

Recently, the roles of FAM83H in tumorigenesis have been interested and increased expression of FAM83H and MYC in hepatocellular carcinoma (HCC) have been reported. Therefore, we investigated the expression and role of FAM83H in 163 human HCCs and further investigated the relationship between FAM83H and oncogene MYC. The expression of FAM83H is elevated in liver cancer cells, and nuclear expression of FAM83H predicted shorter survival of HCC patients. In HLE and HepG2 HCC cells, knock-down of FAM83H inhibited proliferation and invasive activity of HCC cells. FAM83H induced expression of cyclin-D1, cyclin-E1, snail and MMP2 and inhibited the expression of P53 and P27. In hepatic tumor cells derived from Tet-O-MYC mice, the expression of mRNA and protein of FAM83H were dependent on MYC expression. Moreover, a chromatin immunoprecipitation assay demonstrated that MYC binds to the promotor of FAM83H and that MYC promotes the transcription of FAM83H, which was supported by the results of a dual-luciferase reporter assay. In conclusion, we present an oncogenic role of FAM83H in liver cancer, which is closely associated with the oncogene MYC. In addition, our results suggest FAM83H expression as a poor prognostic indicator of HCC patients.

Association of Immunosuppression with DR6 Expression during the Development and Progression of Spontaneous Ovarian Cancer in Laying Hen Model

Ovarian cancer (OVCA) mainly disseminates in the peritoneal cavity. Immune functions are important to prevent OVCA progression and recurrence. The mechanism of immunosuppression, a hallmark of tumor progression, is not well understood. The goal of this study was to determine the immune system's responses and its suppression during OVCA development and progression in hens. Frequencies of CD8+ T cells and IgY-containing cells and expression of immunosuppressors including IRG1 and DR6 in OVCA at early and late stages in hens were examined. Frequencies of stromal but not the intratumoral CD+8 T cells and IgY-containing cells increased significantly (P < 0.01) during OVCA development and progression. Tumor progression was associated with increased expression of IRG1 and DR6 and decreased infiltration of immune cells into the tumor. Frequency of stromal but not intratumoral immune cells increases during OVCA development and progression. Tumor-induced IRG1 and DR6 may prevent immune cells from invading the tumor.

Death receptor 6 (DR6) is required for mouse B16 tumor angiogenesis via the NF-κB, P38 MAPK and STAT3 pathways

Although death receptor 6 (DR6) is aberrantly expressed in certain cancer cell lines, its function, signaling pathway and potential clinical significance in tumor progression are not well characterized. We report here that knocking down DR6 in the mouse B16 cell line has no effect on B16 cell death in vitro but suppresses xenograft B16 tumor growth by preventing tumor blood vessel formation in vivo. Deficiency of DR6 changes cytokine expression and secretion; in particular, it inhibits the proinflammatory cytokine interleukin-6 (IL-6), which is able to induce the expression of the angiogenesis-related factors: vascular endothelial growth factor-A, platelet-derived growth factor-β, vascular endothelial growth factor-D and platelet-derived growth factor receptor-α. Further experiments demonstrate that DR6-dependent angiogenesis is involved in the IL-6/P38 MAPK and IL-6/STAT3 pathways. Our novel findings demonstrate for the first time that DR6 expression in B16 cells facilitates tumor growth by accelerating tumor angiogenesis. Moreover, these results suggest that DR6 is involved in three important intracellular pathways that lead to homeostatic angiogenesis in tumor growth.

ADAM12 is a prognostic factor associated with an aggressive molecular subtype of high-grade serous ovarian carcinoma

ADAM metallopeptidase domain 12 (ADAM12) is a promising biomarker because of its low expression in normal tissues and high expression in a variety of human cancers. However, ADAM12 levels in ovarian cancer have not been well characterized. We previously identified ADAM12 as one of the signature genes associated with poor survival in high-grade serous ovarian carcinoma (HGSOC). Here, we sought to determine if high levels of the ADAM12 protein and/or messenger RNA (mRNA) are associated with clinical variables in HGSOC. We show that high protein levels of ADAM12 in banked preoperative sera are associated with shorter progression-free and overall survival. Tumor levels of ADAM12 mRNA were also associated with shorter progression-free and overall survival as well as with lymphatic and vascular invasion, and residual tumor volume following cytoreductive surgery. The majority of genes co-expressed with ADAM12 in HGSOC were transforming growth factor (TGF)β signaling targets that function in collagen remodeling and cell-matrix adhesion. In tumor sections, the ADAM12 protein and mRNA were expressed in epithelial cancer cells and surrounding stromal cells. In vitro data showed that ADAM12 mRNA levels can be increased by TGFβ signaling and direct contact between epithelial and stromal cells. High tumor levels of ADAM12 mRNA were characteristic of the mesenchymal/desmoplastic molecular subtype of HGSOC, which is known to have the poorest prognosis. Thus, ADAM12 may be a useful biomarker of aggressive ovarian cancer for which standard treatment is not effective.

Identification of novel vascular targets in lung cancer

BACKGROUND

Lung cancer remains the leading cause of cancer-related death, largely owing to the lack of effective treatments. A tumour vascular targeting strategy presents an attractive alternative; however, the molecular signature of the vasculature in lung cancer is poorly explored. This work aimed to identify novel tumour vascular targets in lung cancer.

METHODS

Enzymatic digestion of fresh tissue followed by endothelial capture with Ulex lectin-coated magnetic beads was used to isolate the endothelium from fresh tumour specimens of lung cancer patients. Endothelial isolates from the healthy and tumour lung tissue were subjected to whole human genome expression profiling using microarray technology.

RESULTS

Bioinformatics analysis identified tumour endothelial expression of angiogenic factors, matrix metalloproteases and cell-surface transmembrane proteins. Predicted novel tumour vascular targets were verified by RNA-seq, quantitative real-time PCR analysis and immunohistochemistry. Further detailed expression profiling of STEAP1 on 82 lung cancer patients confirmed STEAP1 as a novel target in the tumour vasculature. Functional analysis of STEAP1 using siRNA silencing implicates a role in endothelial cell migration and tube formation.

CONCLUSIONS

The identification of cell-surface tumour endothelial markers in lung is of interest in therapeutic antibody and vaccine development.

Tumor endothelial marker 1-specific DNA vaccination targets tumor vasculature

Tumor endothelial marker 1 (TEM1; also known as endosialin or CD248) is a protein found on tumor vasculature and in tumor stroma. Here, we tested whether TEM1 has potential as a therapeutic target for cancer immunotherapy by immunizing immunocompetent mice with Tem1 cDNA fused to the minimal domain of the C fragment of tetanus toxoid (referred to herein as Tem1-TT vaccine). Tem1-TT vaccination elicited CD8+ and/or CD4+ T cell responses against immunodominant TEM1 protein sequences. Prophylactic immunization of animals with Tem1-TT prevented or delayed tumor formation in several murine tumor models. Therapeutic vaccination of tumor-bearing mice reduced tumor vascularity, increased infiltration of CD3+ T cells into the tumor, and controlled progression of established tumors. Tem1-TT vaccination also elicited CD8+ cytotoxic T cell responses against murine tumor-specific antigens. Effective Tem1-TT vaccination did not affect angiogenesis-dependent physiological processes, including wound healing and reproduction. Based on these data and the widespread expression of TEM1 on the vasculature of different tumor types, we conclude that targeting TEM1 has therapeutic potential in cancer immunotherapy.

Ultrasound molecular imaging in a human CD276 expression-modulated murine ovarian cancer model

PURPOSE

To develop a mouse ovarian cancer model that allows modulating the expression levels of human vascular targets in mouse xenograft tumors and to test whether expression of CD276 during tumor angiogenesis can be visualized by molecularly targeted ultrasound in vivo.

EXPERIMENTAL DESIGN

CD276-expressing MILE SVEN 1 (MS1) mouse endothelial cells were engineered and used for coinjection with 2008 human ovarian cancer cells for subcutaneous xenograft tumor induction in 15 nude mice. Fourteen control mice were injected with 2008 cells only. After confirming their binding specificity in flow chamber cell attachment studies, anti-CD276 antibody-functionalized contrast microbubbles were used for in vivo CD276-targeted contrast-enhanced ultrasound imaging.

RESULTS

CD276-targeted ultrasound imaging signal was significantly higher (P = 0.006) in mixed MS1/2008 tumors than in control tumors. Compared with control microbubbles, the ultrasound signal using CD276-targeted microbubbles was significantly higher (P = 0.002), and blocking with purified anti-CD276 antibody significantly decreased (P = 0.0096) the signal in mixed MS1/2008 tumors. Immunofluorescence analysis of the tumor tissue confirmed higher quantitative immunofluorescence signal in mixed MS1/2008 tumors than in control 2008 only tumors, but showed not significantly different (P = 0.54) microvessel density.

CONCLUSIONS

Our novel small animal model allows for modulating the expression of human tumor-associated vascular endothelial imaging targets in a mouse host and these expression differences can be visualized noninvasively by ultrasound molecular imaging. The animal model can be applied to other human vascular targets and may facilitate the preclinical development of new imaging probes such as microbubbles targeted at human vascular markers not expressed in mice.

Identification of a Peptide from In vivo Bacteriophage Display with Homology to EGFL6: A Candidate Tumor Vasculature Ligand in Breast Cancer

Background

A crucial step in tumorigenesis is the recruitment of novel vasculature to the site of neoplasia. Currently, a number of high throughput techniques are employed to identify genes, mRNA and proteins that are aberrantly expressed in tumor vasculature. One drawback of such techniques is the lack of functional in vivo data that they provide. Bacteriophage (phage) display has been demonstrated in vivo to select peptides that home to tumors and tumor vasculature. The peptides can be compared to sequences of putative cancer-related proteins, in order to identify novel proteins essential for tumorigenesis.

Objectives

It was hypothesized that an in vivo selection for phage which targeted human breast cancer xenografts could identify peptides with homology to cancer-related proteins for in vivo imaging of breast cancer.

Methods

Following four rounds of in vivo selection in human MDA-MB-435 breast cancer xenografted mice, peptide 3-G03 was discovered with significant homology to a putative secreted protein termed EGFL6. Egfl6 mRNA is upregulated in several transcriptomic analyses of human cancer biopsies, and the protein may play a role in tumor vascularization.

Results

Egfl6 mRNA expression was demonstrated in MDA-MB-435 cells and EGFL6 protein was secreted from these cells. Based on homology of 3-G03 to EGFL6, an EGFL6 peptide was synthesized and shown to target MDA-MB-435 cells. EGFL6 peptide was radiolabeled with ¹¹¹In and analyzed for biodistribution and tumor imaging capabilities. Single photon emission computed tomography imaging revealed uptake of the peptide in a manner consistent with other tumor vasculature targeting agents.

ADAM12 is expressed in the tumour vasculature and mediates ectodomain shedding of several membrane-anchored endothelial proteins

ADAM (a disintegrin and metalloproteinase) 12 is a metalloprotease implicated in cancer progression. ADAM12 can activate membrane-anchored proteins, such as sonic hedgehog, Delta-like 1 and certain epidermal growth factor receptor ligands, through a process called ectodomain shedding. We screened several membrane-anchored proteins to further dissect the substrate profile of ADAM12-mediated ectodomain shedding, and found shedding of five previously unreported substrates [Kitl1, VE-cadherin (vascular endothelial cadherin), Flk-1 (fetal liver kinase 1), Tie-2, and VCAM-1 (vascular cell adhesion molecule 1)], of which the latter four are specifically expressed by endothelial cells. We also observed that ADAM12 expression was increased in the tumour vasculature of infiltrating ductal carcinoma of the human breast as compared with little to no expression in normal breast tissue vasculature, suggesting a role for ADAM12 in tumour vessels. These results prompted us to further evaluate ADAM12-mediated shedding of two endothelial cell proteins, VE-cadherin and Tie-2. Endogenous ADAM12 expression was very low in cultured endothelial cells, but was significantly increased by cytokine stimulation. In parallel, the shed form of VE-cadherin was elevated in such cytokine-stimulated endothelial cells, and ADAM12 siRNA (small interfering RNA) knockdown reduced cytokine-induced shedding of VE-cadherin. In conclusion, the results of the present study demonstrate a role for ADAM12 in ectodomain shedding of several membrane-anchored endothelial proteins. We speculate that this process may have importance in tumour neovascularization or/and tumour cell extravasation.

A Phase I vaccine trial using dendritic cells pulsed with autologous oxidized lysate for recurrent ovarian cancer

Purpose

Ovarian cancer, like most solid tumors, is in dire need of effective therapies. The significance of this trial lies in its promise to spearhead the development of combination immunotherapy and to introduce novel approaches to therapeutic immunomodulation, which could enable otherwise ineffective vaccines to achieve clinical efficacy.

Rationale

Tumor-infiltrating T cells have been associated with improved outcome in ovarian cancer, suggesting that activation of antitumor immunity will improve survival. However, molecularly defined vaccines have been generally disappointing. Cancer vaccines elicit a modest frequency of low-to-moderate avidity tumor-specific T-cells, but powerful tumor barriers dampen the engraftment, expansion and function of these effector T-cells in the tumor, thus preventing them from reaching their full therapeutic potential. Our work has identified two important barriers in the tumor microenvironment: the blood-tumor barrier, which prevents homing of effector T cells, and T regulatory cells, which inactivate effector T cells. We hypothesize that cancer vaccine therapy will benefit from combinations that attenuate these two barrier mechanisms.

Design

We propose a three-cohort sequential study to investigate a combinatorial approach of a new dendritic cell (DC) vaccine pulsed with autologous whole tumor oxidized lysate, in combination with antiangiogenesis therapy (bevacizumab) and metronomic cyclophosphamide, which impacts Treg cells.

Innovation

This study uses a novel autologous tumor vaccine developed with 4-day DCs pulsed with oxidized lysate to elicit antitumor response. Furthermore, the combination of bevacizumab with a whole tumor antigen vaccine has not been tested in the clinic. Finally the combination of bevacizumab and metronomic cyclophosphamide in immunotherapy is novel.

A novel mechanism of keratin cytoskeleton organization through casein kinase Iα and FAM83H in colorectal cancer

Keratin filaments form cytoskeletal networks in epithelial cells. Dynamic rearrangement of keratin filament networks is required for epithelial cells to perform cellular processes such as cell migration and polarization; however, the mechanism governing keratin filament rearrangement remains unclear. Here, we found a novel mechanism of keratin cytoskeleton organization mediated by casein kinase Iα (CK-1α) and a newly identified keratin-associated protein, FAM83H. FAM83H knockdown induces keratin filament bundling, whereas FAM83H overexpression disassembles keratin filaments, suggesting that FAM83H regulates the filamentous state of keratins. Intriguingly, keratin filament bundling is concomitant with the dissociation of CK-1α from keratin filaments, while aberrant speckle-like localization of CK-1α is observed concomitantly with keratin filament disassembly. Furthermore, CK-1α inhibition, like FAM83H knockdown, causes keratin filament bundling and reverses keratin filament disassembly induced by FAM83H overexpression, suggesting that CK-1α mediates FAM83H-dependent reorganization of keratin filaments. Since the N-terminal region of FAM83H interacts with CK-1α, whereas the C-terminal region interacts with keratins, FAM83H might tether CK-1α to keratins. Colorectal cancer tissue also shows keratin filament disassembly accompanied with FAM83H overexpression and aberrant CK-1α localization, and FAM83H-overexpressing cancer cells exhibit loss or alteration of epithelial cell polarity. Importantly, FAM83H knockdown inhibits cell migration accompanied by keratin cytoskeleton rearrangement in colorectal cancer cells. These results suggest that keratin cytoskeleton organization is regulated by FAM83H-mediated recruitment of CK-1α to keratins, and that keratin filament disassembly caused by FAM83H overexpression and aberrant localization of CK-1α may contribute to the progression of colorectal cancer.

Lysophosphatidic acid-induced ADAM12 expression mediates human adipose tissue-derived mesenchymal stem cell-stimulated tumor growth

Lysophosphatidic acid (LPA) is involved in mesenchymal stem cell-stimulated tumor growth in vivo. However, the molecular mechanism by which mesenchymal stem cells promote tumorigenesis remains elusive. In the present study, we demonstrate that conditioned medium from A549 human lung adenocarcinoma cells (A549 CM) induced the expression of ADAM12, a disintegrin and metalloproteases family member, in human adipose tissue-derived mesenchymal stem cells (hASCs). A549 CM-stimulated ADAM12 expression was abrogated by pretreatment of hASCs with the LPA receptor 1 inhibitor Ki16425 or by small interfering RNA-mediated silencing of LPA receptor 1, suggesting a key role for the LPA-LPA receptor 1 signaling axis in A549 CM-stimulated ADAM12 expression. Silencing of ADAM12 expression using small interfering RNA or short hairpin RNA abrogated LPA-induced expression of both α-smooth muscle actin, a marker of carcinoma-associated fibroblasts, and ADAM12 in hASCs. Using a xenograft transplantation model of A549 cells, we demonstrated that silencing of ADAM12 inhibited the hASC-stimulated in vivo growth of A549 xenograft tumors and the differentiation of transplanted hASCs to α-smooth muscle actin-positive carcinoma-associated fibroblasts. LPA-conditioned medium from hASCs induced the adhesion of A549 cells and silencing of ADAM12 inhibited LPA-induced expression of extracellular matrix proteins, periostin and βig-h3, in hASCs and LPA-conditioned medium-stimulated adhesion of A549 cells. These results suggest a pivotal role for LPA-stimulated ADAM12 expression in tumor growth and the differentiation of hASCs to carcinoma-associated fibroblasts expressing α-smooth muscle actin, periostin, and βig-h3.

Expression of death receptor 6 by ovarian tumors in laying hens, a preclinical model of spontaneous ovarian cancer

Tumor-associated neoangiogenesis and suppression of antitumor immunity are hallmarks of tumor development and progression. Death receptor 6 (DR6) has been reported to be associated with suppression of antitumor immunity and tumor progression in several malignancies. However, expression of DR6 by malignant ovarian epithelial tumors at an early stage is unknown. The goals of this study were to determine whether DR6 is expressed by malignant ovarian epithelial tumors at an early stage and to examine whether DR6 expression is associated with ovarian cancer (OVCA) progression in a laying hen model of spontaneous OVCA. Expression of DR6 was examined in normal and malignant ovaries, normal ovarian surface epithelial (OSE) cells, or malignant epithelial cells and in serum of 3-year-old hens. The population of microvessels expressing DR6 was significantly higher in hens with early-stage OVCA than hens with normal ovaries (P < .01) and increased further in late-stage OVCA. The results of this study showed that, in addition to microvessels, tumor cells in the ovary also express DR6 with a significantly higher intensity than normal OSE cells. Similar patterns of DR6 expression were also observed by immunoblot analysis and gene expression studies. Furthermore, DR6 was also detected in the serum of hens. In conclusion, DR6 expression is associated with OVCA development and progression in laying hens. This study may be helpful to examine the feasibility of DR6 as a useful surrogate marker of OVCA, a target for antitumor immunotherapy and molecular imaging and thus provide a foundation for clinical studies.