Ovarian cancer immuno-reactive antigen domain containing 1 (OCIAD1), a key player in ovarian cancer cell adhesion

High Expression of TMEM33 Predicts Poor Prognosis and Promotes Cell Proliferation in Cervical Cancer

Background: The prognosis of patients with advanced cervical cancer remains unsatisfactory. A study indicated that transmembrane protein 33 (TMEM33) was implicated in tumor recurrence, while its role in cervical cancer has not been elucidated.

Methods: TMEM33 expression in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) was primarily screened in The Cancer Genome Atlas (TCGA), and further validated in Gene Expression Omnibus (GEO) database. The Kaplan–Meier plotter analysis and Cox regression were constructed to evaluate the prognostic value of TMEM33 in CESC. Functional enrichment analysis was performed with GO, KEGG and GSEA tools. CCK-8 assay and colony formation assay were performed to investigate the carcinogenesis role of TMEM33 in cervical cancer cell proliferation.

Results: TMEM33 expression was significantly elevated in CESC compared with normal tissues. High expression of TMEM33 was associated with poor prognostic clinical characteristics in CESC patients. KM-plotter analysis revealed that patients with increased TMEM33 had shorter overall survival (OS), progress free interval (PFI), and disease specific survival (DSS). Moreover, Multivariate Cox analysis confirmed that high TMEM33 expression was an independent risk factor for OS in patients with CESC. TMEM33 was associated with immune infiltrates, and its expression was correlated with tumorigenesis-related genes RNF4, OCIAD1, TMED5, DHX15, MED28 and LETM1. More importantly, knockdown of TMEM33 in cervical cancer cells decreased the expression of those genes and inhibited cell proliferation.

Conclusion: Increased TMEM33 in cervical cancer can serve as an independent prognostic marker and might play a role in tumorigenesis by promoting cell proliferation.

Cellular OCIAD2 protein is a proviral factor for hepatitis C virus replication

Hepatitis C virus (HCV) nonstructural protein NS4B is necessary for HCV replication. Our previous research found that NS4B-associated cellular proteins PREB and Surfeit 4 are involved in HCV replication. However, the molecular mechanism of HCV replication is not fully understood. Here we identified cellular ovarian cancer immunoreactive antigen domain containing 2 (OCIAD2) protein as a novel NS4B-associated HCV host cofactor by screening with small interfering RNA. Knockdown of OCIAD2 reduced significantly the HCV replication in a dose-dependent and genotype-independent manner. Further research showed that OCIAD2 was recruited into the HCV RNA replication complex by the interaction with NS4B. Interestingly, HCV replication induced OCIAD2 expression. In turn, overexpression of wild OCIAD2 also promoted virus replication whereas that of OCIAD2 mutant lacking the ability to bind NS4B exerted no effect on HCV replication. We also examined whether OCIAD2 interacted with other proteins participating in the HCV RNA replication complex including viral proteins NS5A, NS5B, and cellular proteins PREB, Surfeit 4. The results showed that OCIAD2 interacted with PREB and NS5A, but not NS5B or Surfeit 4. Our findings provide new insights into the function of OCIAD2 and HCV replication mechanism.

Expression, Purification and Crystallization of Asrij, A Novel Scaffold Transmembrane Protein

Asrij/OCIAD1 is a scaffold transmembrane protein belonging to the Ovarian Carcinoma Immunoreactive Antigen Domain containing protein family. In Drosophila and mouse models, Asrij localizes at the endosomal and mitochondrial membrane and is shown to regulate the stemness of hematopoietic stem cells. Interaction of Asrij with ADP Ribosylation Factor 1 (Arf1) is shown to be crucial for hematopoietic niche function and prohemocyte maintenance. Here, we report the heterologous expression, standardization of detergents and purification methodologies for crystallization of Asrij/OCIAD1. To probe the activity of bacterially expressed Asrij, we developed a protein complementation assay and conclusively show that Asrij and Arf1 physically interact. Further, we find that sophorolipids improve the solubility and monodispersibility of Asrij. Hence, we propose that sophorolipids could be novel additives for stabilization of membrane proteins. To our knowledge, this is the first study detailing methodology for the production and crystallization of a heterologously expressed scaffold membrane protein and will be widely applicable to understand membrane protein structure and function.

OCIAD1 is a host mitochondrial substrate of the hepatitis C virus NS3-4A protease

The hepatitis C virus (HCV) nonstructural protein 3-4A (NS3-4A) protease is a key component of the viral replication complex and the target of protease inhibitors used in current clinical practice. By cleaving and thereby inactivating selected host factors it also plays a role in the persistence and pathogenesis of hepatitis C. Here, we describe ovarian cancer immunoreactive antigen domain containing protein 1 (OCIAD1) as a novel cellular substrate of the HCV NS3-4A protease. OCIAD1 was identified by quantitative proteomics involving stable isotopic labeling using amino acids in cell culture coupled with mass spectrometry. It is a poorly characterized membrane protein believed to be involved in cancer development. OCIAD1 is cleaved by the NS3-4A protease at Cys 38, close to a predicted transmembrane segment. Cleavage was observed in heterologous expression systems, the replicon and cell culture-derived HCV systems, as well as in liver biopsies from patients with chronic hepatitis C. NS3-4A proteases from diverse hepacivirus species efficiently cleaved OCIAD1. The subcellular localization of OCIAD1 on mitochondria was not altered by NS3-4A-mediated cleavage. Interestingly, OCIAD2, a homolog of OCIAD1 with a cysteine residue in a similar position and identical subcellular localization, was not cleaved by NS3-4A. Domain swapping experiments revealed that the sequence surrounding the cleavage site as well as the predicted transmembrane segment contribute to substrate selectivity. Overexpression as well as knock down and rescue experiments did not affect the HCV life cycle in vitro, raising the possibility that OCIAD1 may be involved in the pathogenesis of hepatitis C in vivo.

OCIAD1 promoted pancreatic ductal adenocarcinoma migration by regulating ATM

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive neoplastic disease, characterized with poor outcomes and a 5-year survival rate less than 5%. Dysregulation or dysfunction of immune response factors contribute to cancer development. In this study, we found that OCIAD1 is high expressed in pancreatic cancer gene chip, and verified OCIAD1 associating with cancer malignancy in specimens from patients with PDAC. OCIAD1 down-regulation inhibited PDAC cell lines migration and vice versa. Further analysis of pancreatic cancer gene chip found OCIAD1 high expression was associating with low ATM expression. Then we proved that OCIAD1 regulated ATM to affect the migration of PDAC. Thus we concluded that high OCIAD1 levels in PDAC promoted tumor cells migration. OCIAD1 exerted its effects by regulating ATM.

Proteomics of Asrij Perturbation in Drosophila Lymph Glands for Identification of New Regulators of Hematopoiesis

Hematopoiesis is the process of differentiation of precursor blood cells into mature blood cells that is controlled by a complex set of molecular interactions. Understanding hematopoiesis is important for the study of hematological disorders. However, a comprehensive understanding of how physiological and genetic mechanisms regulate blood cell precursor maintenance and differentiation is lacking. Owing to simplicity and ease of genetic analysis, the Drosophila melanogaster lymph gland (LG) is an excellent model to study hematopoiesis. Here, we quantitatively analyzed the LG proteome under genetic conditions that either maintain precursors or promote their differentiation in vivo, by perturbing expression of Asrij, a conserved endosomal regulator of hematopoiesis. Using iTRAQ-based quantitative proteomics, we determined the relative expression levels of proteins in Asrij-knockout and overexpressing LGs from 1500 larval dissections compared with wild type. Our data showed that at least 6.5% of the Drosophila proteome is expressed in wild type LGs. Of the 2133 proteins identified, 780 and 208 proteins were common to previously reported cardiac tube and hemolymph proteomes, respectively, resulting in the identification of 1238 proteins exclusive to the LG. Perturbation of Asrij levels led to differential expression of 619 proteins, of which 27% have human homologs implicated in various diseases. Proteins regulating metabolism, immune system, signal transduction and vesicle-mediated transport were significantly enriched. Immunostaining of representative candidates from the enriched categories and previous reports confirmed 73% of our results, indicating the validity of our LG proteome. Our study provides, for the first time, an in vivo proteomics resource for identifying novel regulators of hematopoiesis that will also be applicable to understanding vertebrate blood cell development.

Drosophila Jak/STAT Signaling: Regulation and Relevance in Human Cancer and Metastasis

Over the past three-decades, Janus kinase (Jak) and signal transducer and activator of transcription (STAT) signaling has emerged as a paradigm to understand the involvement of signal transduction in development and disease pathology. At the molecular level, cytokines and interleukins steer Jak/STAT signaling to transcriptional regulation of target genes, which are involved in cell differentiation, migration, and proliferation. Jak/STAT signaling is involved in various types of blood cell disorders and cancers in humans, and its activation is associated with carcinomas that are more invasive or likely to become metastatic. Despite immense information regarding Jak/STAT regulation, the signaling network has numerous missing links, which is slowing the progress towards developing drug therapies. In mammals, many components act in this cascade, with substantial cross-talk with other signaling pathways. In Drosophila, there are fewer pathway components, which has enabled significant discoveries regarding well-conserved regulatory mechanisms. Work across species illustrates the relevance of these regulators in humans. In this review, we showcase fundamental Jak/STAT regulation mechanisms in blood cells, stem cells, and cell motility. We examine the functional relevance of key conserved regulators from Drosophila to human cancer stem cells and metastasis. Finally, we spotlight less characterized regulators of Drosophila Jak/STAT signaling, which stand as promising candidates to be investigated in cancer biology. These comparisons illustrate the value of using Drosophila as a model for uncovering the roles of Jak/STAT signaling and the molecular means by which the pathway is controlled.

OCIAD1 Controls Electron Transport Chain Complex I Activity to Regulate Energy Metabolism in Human Pluripotent Stem Cells

Pluripotent stem cells (PSCs) derive energy predominantly from glycolysis and not the energy-efficient oxidative phosphorylation (OXPHOS). Differentiation is initiated with energy metabolic shift from glycolysis to OXPHOS. We investigated the role of mitochondrial energy metabolism in human PSCs using molecular, biochemical, genetic, and pharmacological approaches. We show that the carcinoma protein OCIAD1 interacts with and regulates mitochondrial complex I activity. Energy metabolic assays on live pluripotent cells showed that OCIAD1-depleted cells have increased OXPHOS and may be poised for differentiation. OCIAD1 maintains human embryonic stem cells, and its depletion by CRISPR/Cas9-mediated knockout leads to rapid and increased differentiation upon induction, whereas OCIAD1 overexpression has the opposite effect. Pharmacological alteration of complex I activity was able to rescue the defects of OCIAD1 modulation. Thus, hPSCs can exist in energy metabolic substates. OCIAD1 provides a target to screen for additional modulators of mitochondrial activity to promote transient multipotent precursor expansion or enhance differentiation.

•

OCIAD1 regulates energy metabolism in human pluripotent stem cells

•

OCIAD1 interacts with electron transport chain proteins and downregulates OXPHOS

•

OCIAD1 regulates complex I activity and early mesodermal progenitor formation

•

Pharmacological increase in complex I activity enhances stem cell differentiation

4-protein signature predicting tamoxifen treatment outcome in recurrent breast cancer

Estrogen receptor (ER) positive tumors represent the majority of breast malignancies, and are effectively treated with hormonal therapies, such as tamoxifen. However, in the recurrent disease resistance to tamoxifen therapy is common and a major cause of death. In recent years, in-depth proteome analyses have enabled identification of clinically useful biomarkers, particularly, when heterogeneity in complex tumor tissue was reduced using laser capture microdissection (LCM). In the current study, we performed high resolution proteomic analysis on two cohorts of ER positive breast tumors derived from patients who either manifested good or poor outcome to tamoxifen treatment upon recurrence. A total of 112 fresh frozen tumors were collected from multiple medical centers and divided into two sets: an in-house training and a multi-center test set. Epithelial tumor cells were enriched with LCM and analyzed by nano-LC Orbitrap mass spectrometry (MS), which yielded >3000 and >4000 quantified proteins in the training and test sets, respectively. Raw data are available via ProteomeXchange with identifiers PXD000484 and PXD000485. Statistical analysis showed differential abundance of 99 proteins, of which a subset of 4 proteins was selected through a multivariate step-down to develop a predictor for tamoxifen treatment outcome. The 4-protein signature significantly predicted poor outcome patients in the test set, independent of predictive histopathological characteristics (hazard ratio [HR] = 2.17; 95% confidence interval [CI] = 1.15 to 4.17; multivariate Cox regression p value = 0.017). Immunohistochemical (IHC) staining of PDCD4, one of the signature proteins, on an independent set of formalin-fixed paraffin-embedded tumor tissues provided and independent technical validation (HR = 0.72; 95% CI = 0.57 to 0.92; multivariate Cox regression p value = 0.009). We hereby report the first validated protein predictor for tamoxifen treatment outcome in recurrent ER-positive breast cancer. IHC further showed that PDCD4 is an independent marker.

Ovarian cancer microenvironment: implications for cancer dissemination and chemoresistance acquisition

Ovarian adenocarcinoma is characterized by a late detection, dissemination of cancer cells into the whole peritoneum, and the frequent acquisition of chemoresistance. If these particularities can be explained in part by intrinsic properties of ovarian cancer cells, an increased number of studies show the importance of the tumor microenvironment in tumor progression. Ovarian cancer cells can regulate the composition of their stroma in promoting the formation of ascitic fluid, rich in cytokines and bioactive lipids, and in stimulating the differentiation of stromal cells into a pro-tumoral phenotype. In return, cancer-associated fibroblasts, cancer-associated mesenchymal stem cells, tumor-associated macrophages, or other peritoneal cells, such as adipocytes and mesothelial cells can regulate tumor growth, angiogenesis, dissemination, and chemoresistance. This review focuses on the current knowledge about the roles of stromal cells and the associated secreted factors on tumor progression. We also summarize the different studies showing that targeting the microenvironment represents a great potential for improving the prognosis of patients with ovarian adenocarcinoma.

Conserved regulation of the Jak/STAT pathway by the endosomal protein asrij maintains stem cell potency

Asrij/OCIAD1 is an endosomal protein expressed in stem cells and cardiovascular lineages and aberrantly expressed in several cancers. We show that dose-dependent modulation of cytokine-dependent JAK/STAT signaling by Asrij regulates mouse embryonic stem cell pluripotency as well as Drosophila hematopoietic stem cell maintenance. Furthermore, mouse asrij can substitute for Drosophila asrij, indicating that they are true homologs. We identify a conserved region of Asrij that is necessary and sufficient for vesicular localization and function. We also show that Asrij and STAT3 colocalize in endosomes and interact biochemically. We propose that Asrij provides an endosomal scaffold for STAT3 interaction and activation, and may similarly control other circuits that maintain stemness. Thus, Asrij provides a key point of control for spatial and kinetic regulation of stem cell signals.

The influence of neural cell adhesion molecule isoform 140 on the metastasis of thyroid carcinoma

We previously showed that the preservation of neural adhesion molecule (NCAM) in differentiated thyroid carcinoma is an important indicator for a higher risk of distant metastasis. In the present study, we further demonstrated that forced NCAM-140 isoform expression in human thyroid cancer cells could lead to aggressive growth by enhancing migration and anchorage-independent growth, and exhibiting partial features of epithelial mesenchymal transition. More extensive distant metastasis was also noted in an animal xenograft model when NCAM-expressing thyroid cancer cells were introduced into mice intravascularly. Bioinformatic analysis of NCAM-associated expression profiles predicted a highly interactive protein network, which further implies potential molecular mechanisms underlying the metastatic processes of thyroid cancer.

Interactions between the ROP18 kinase and host cell proteins that aid in the parasitism of Toxoplasma gondii

Serine/threonine kinases secreted from rhoptry organelles are important virulence factors for Toxoplasma gondii. Among rhoptry proteins, the ROP18 kinase has been identified as a key virulence determinant mediating pathogenesis in T. gondii; however, the molecular mechanisms by which this kinase exerts its pathogenic action remain poorly understood. In this study, the interactions between the ROP18 kinase of Toxoplasma gondii and the host cell proteins were analyzed using a yeast two-hybrid technique. The cMyc-ROP18(25-251) fusion proteins expressed by pGBKT7 plasmids in AH109 yeast were bound to host cell proteins from a human fetal brain cDNA library transformed to AH109 yeast using a mating method. Using these selection procedures, we identified seven host proteins that had not previously been reported to interact with ROP18 such as DDB1, TOR1AIP1, integrin, SLC3A2, TPST2, DERL2 and OCIAD1. These host proteins are associated with DNA repair, transcriptional regulation, translation modification, protein degradation and cell adhesion. Our data strongly support the hypothesis that the secreted kinase ROP18 is involved in several complex cellular pathways for the invasion and commandeering of host functions.

Increased expression of OCIA domain containing 2 during stepwise progression of ovarian mucinous tumor

Ovarian cancer immunoreactive antigen domain containing 2 (OCIAD2) has been reported to show cancer-specific expression in early invasive lung adenocarcinoma. OCIAD2 shows high homology with OCIAD1, which was originally immunoscreened from ascites of a patient with ovarian cancer and found to be a tumor-specific protein. Therefore, like OCIAD1, OCIAD2 is expected to show high immunoreactivity in ovarian tumors. In this study, we examined the expression pattern of OCIAD2 in 117 ovarian mucinous tumors, and confirmed that it was more highly expressed in borderline tumor and carcinoma (51/74 cases, 69%) than in adenoma (6/43 cases, 14%). The immunoreactivity of OCIAD2 in borderline tumor and carcinoma was more specific than that of OCIAD1 (adenoma, 21/43 cases, 49%), and more sensitive than that of CEA (borderline tumor and carcinoma, 35/74 cases, 47%). Like OCIAD1, OCIAD2 is a cancer-related protein and its expression level increases during the course of malignant progression and is thought to be a very useful marker for evaluating the malignancy of ovarian mucinous tumors.

S. S, Inamdar MS. Asrij maintains the stem cell niche and controls differentiation during Drosophila lymph gland hematopoiesis

Several signaling pathways control blood cell (hemocyte) development in the Drosophila lymph gland. Mechanisms that modulate and integrate these signals are poorly understood. Here we report that mutation in a conserved endocytic protein Asrij affects signal transmission and causes aberrant lymph gland hematopoiesis. Mammalian Asrij (Ociad1) is expressed in stem cells of the blood vascular system and is implicated in several cancers. We found that Drosophila Asrij is a pan-hemocyte marker and localizes to a subset of endocytic vesicles. Loss of asrij causes hyperproliferation of lymph gland lobes coupled with increased hemocyte differentiation, thereby depleting the pool of quiescent hemocyte precursors. This co-relates with fewer Col+ cells in the hematopoietic stem cell niche of asrij mutants. Asrij null mutants also show excess specification of crystal cells that express the RUNX factor Lozenge (Lz), a target of Notch signaling. Asrij mutant lymph glands show increased N in sorting endosomes suggesting aberrant trafficking. In vitro assays also show impaired traffic of fluorescent probes in asrij null hemocytes. Taken together our data suggest a role for Asrij in causing increased Notch signaling thereby affecting hemocyte differentiation. Thus, conserved endocytic functions may control blood cell progenitor quiescence and differentiation.

Role of the 18:1 lysophosphatidic acid-ovarian cancer immunoreactive antigen domain containing 1 (OCIAD1)-integrin axis in generating late-stage ovarian cancer

Chemotherapy resistance in ovarian cancer remains an unsolved problem in caring for women with this disease. We now show that ovarian cancer immunoreactive antigen domain containing 1 (OCIAD1) has higher expression in chemoresistant compared with chemosensitive ovarian cancer cell lines. We have designed a novel secondary cell homing assay (SCHA) to test the ability of cells to withstand chemotherapy and form secondary colonies that could form recurrent disease. OCIAD1 upregulated cells had significantly higher secondary colony-forming ability than had OCIAD1 downregulated cells following treatment with paclitaxel. Additionally, 18:1 lysophosphatidic acid (LPA) increases OCIAD1 expression in a time- and dose-dependent manner. LPA stimulates OCIAD1 serine phosphorylation within two hours of stimulation. Transfection of MKK6 increases OCIAD1 expression but nuclear translocation is inhibited. Inhibition of p38 mitogen-activated protein kinase blocks LPA-induced OCIAD1 expression. Cycloheximide treatment of MKK6-transfected cells does not inhibit OCIAD1 expression, suggesting that MKK6 upregulation is not translationally controlled. OCIAD1 downregulation knocks down LPA-induced cell adhesion to collagen I and laminin 10/11 and specifically inhibits cell attachment to alpha2, alpha5, alphaV, and beta1 integrins. Proteomic studies indicate that OCIAD1 is physically attached to alpha actin 4 and beta actin. Thus, OCIAD1 may play a role in cytoskeletal function which can alter sensitivity to paclitaxel. This is the first study to indicate that OCIAD1 is a key player in generating ovarian cancer recurrence; it is functionally controlled by LPA and MKK6 signaling, and inhibition of OCIAD1 could be an important strategy in the management of recurrent ovarian cancer.

Analysis of gene expression in stage I serous tumors identifies critical pathways altered in ovarian cancer

OBJECTIVE

Despite recent advances in the conceptual understanding of the pathogenesis of ovarian cancer, it remains the foremost cause of death from gynecologic malignancies in developed countries. The main reason for such a high rate of mortality is the lack of sensitive and specific biomarkers and imaging techniques for early detection of ovarian cancer. Additional biological insights into early-stage ovarian carcinogenesis are needed to help speed the development of markers for early detection of ovarian cancer. The objective of this study was to characterize differentially expressed genes in high-grade stage I serous carcinoma of the ovary.

METHODS

We analyzed gene expression in macrodissected formalin-fixed, paraffin-embedded samples from 5 high-grade stage I serous carcinomas and 5 stage I borderline tumors of the ovary using the Illumina Whole Genome DASL assay (cDNA-mediated annealing, selection, extension, and ligation) corresponding to 24,000 genes. Significance Analysis of Microarrays was performed to determine differentially expressed genes in stage I serous carcinoma, and class prediction analysis was performed to determine the predictive value of differentially expressed gene sets to correctly classify serous carcinoma from borderline tumors in 3 independent data sets. Altered transcription factor pathways and biological pathways unique to stage I serous carcinoma were identified through class comparison of differentially expressed genes.

RESULTS

Unsupervised cluster analysis of gene expression correctly classified stage I serous carcinomas from serous borderline tumors. Supervised analysis identified several known, as well as novel, genes differentially expressed in stage I ovarian cancer. Using a differentially expressed gene set, class comparison prediction analysis correctly identified serous carcinomas from serous borderline tumors in 3 independent data sets at over 80% accuracy, sensitivity, and specificity. Pathway analysis demonstrated the significance of p53 and E2F pathways in serous carcinogenesis and significant involvements of cell cycle and immune response pathways in stage I serous epithelial ovarian cancer.

CONCLUSION

We have identified differentially expressed genes associated with the carcinogenesis of high-grade stage I serous EOC. Furthermore, integrative analysis of biological and transcription pathway data contributed to the confirmation of important biological pathways and discovery of additional unique genes and pathways that may have potential importance in ovarian pathogenesis and biomarker development.