Molecular cloning of Frizzled-10, a novel member of the Frizzled gene family

MiR-26b-3p Promotes Intestinal Motility Disorder by Targeting FZD10 to Inhibit GSK3β/β-Catenin Signaling and Induce Enteric Glial Cell Apoptosis

Enteric glial cells (EGCs) are the major component of the enteric nervous system and affect the pathophysiological process of intestinal motility dysfunction. MicroRNAs (miRNAs) play an important role in regulating gastrointestinal homeostasis. However, the mechanism of miRNA-mediated regulation of EGCs in intestinal dysmotility remains unclear. In this study, we investigated the effect of EGC apoptosis on intestinal dysmotility, and the effect of miR-26b-3p on EGC proliferation and apoptosis in vivo and in vitro. A loperamide hydrochloride (Lop)-induced constipated mouse model and an in vitro culture system of rat EGCs were established. The transcriptome was used to predict the differentially expressed gene miR-26b-3p and the target gene Frizzled 10 (FZD10), and their targeting binding relationship was verified by luciferase. EGCs were transfected with miR-26b-3p mimic or antagomir, and the FZD10 expression was down-regulated by siRNA. Immunofluorescence and flow cytometry were used to detect EGC apoptosis. MiR-26b-3p and FZD10 expressions were examined using quantitative real-time PCR (qRT-PCR). The CCK-8 assay was used to detect EGC proliferation. The protein levels were detected by Western blotting and enzyme-linked immunosorbent assay (ELISA). The results showed that miR-26b-3p was up-regulated in the Lop group, whereas FZD10 was down-regulated, and EGC apoptosis was increased in the colon of intestinal dysmotility mice. FZD10 down-regulation and miR-26b-3p mimic significantly increased glycogen synthase kinase-3β phosphorylation (p-GSK3β) levels, decreased β-catenin expression, and promoted EGC apoptosis. MiR-26b-3p antagomir alleviated intestinal dysmotility, promoted EGC increased activity of EGCs, and reduced EGC apoptosis in vivo. In conclusion, this study indicated that miR-26b-3p promotes intestinal motility disorders by targeting FZD10 to block GSK3β/β-catenin signaling and induces apoptosis in EGCs. Our results provide a new research target for the treatment and intervention of intestinal dysmotility.

Upregulation of SOX9 promotes the self-renewal and tumorigenicity of cervical cancer through activating the Wnt/β-catenin signaling pathway

Sry-box9 (SOX9) maintains stem cell properties and plays crucial roles in many cancers. However, whether SOX9 is correlated with cervical cancer cell stemness and its detailed mechanism remains obscure. We studied the relationship between SOX9 and prognosis of cervical cancer through public database, and SOX9 was related to poor prognosis of cervical cancer. Elevated SOX9 expression enhanced the self-renewal properties and promotes tumorigenicity in cervical cancer. Overexpression of SOX9 could promote the expression of stem cell-related factors in cervical cancer cells and xenografts. Meanwhile, overexpression of SOX9 could also enhance the expressions of FZD10, β-catenin, and c-Myc in cervical cancer cells and xenografts, while inhibiting the expression of DDK1. The activation of Wnt pathway by chir-99 021 raised the tumor spheroid ability of SOX9 knockdown HeLa cells. In addition, SOX9 could transcriptional inhibit DKK1 and activate FZD10 and MYC by binding to their promoters to affect the Wnt/β-catenin pathway. These results demonstrated SOX9 regulated the self-renewal and tumorigenicity of cervical cancer through Wnt/β-catenin pathway by directly transcriptional activation of FZD10, MYC and transcriptional inhibition of DKK1.

Research and Development for Cyclotron Production of 225Ac from 226Ra—The Challenges in a Country Lacking Natural Resources for Medical Applications

The high therapeutic effect of targeted radioisotope/radionuclide therapy (TRT) using α-emitters, especially 225Ac, is attracting attention worldwide. However, the only 225Ac production method that has been put into practical use is extraction from a 229Th generator derived from the nuclear fuel 233U, and it is unlikely that this method alone is able to meet future global medical demand. Development towards new 225Ac production methods is in progress. These new 225Ac production methods require the irradiation of 232Th or 226Ra using an accelerator or a nuclear reactor. Global competition has already begun in the race to secure a reliable supply of 232Th and 226Ra, as well as 229Th for the conventional production method. Japan is a “resource-poor country” that depends on foreign countries for most of its needs. As such, it is difficult for Japan to secure raw materials such as 232Th and 226Ra for medical application. In this paper, we look back on our research at the National Institutes for Quantum Science and Technology (QST) in the fields of 225Ac production and 225Ac-labeled pharmaceutical development. We present the history and details of our research from 2011, as well as the development of a collaboration between QST and Nihon Medi-Physics that focuses on research into 225Ac production via 226Ra(p,2n)225Ac reaction using an accelerator. Furthermore, we review the valuable discussion at the 2018 Joint IAEA-JRC Workshop—“Supply of Actinium-225”, an international conference that we participated in. Overall, the statuses of external 225Ac supply, domestic production, and distribution are discussed, as are the latest developments in 225Ac production methods, 225Ac pharmaceuticals, and future prospects for the domestic production of 225Ac in Japan, a country lacking natural resources for medical applications.

FZD10-targeted α-radioimmunotherapy with 225 Ac-labeled OTSA101 achieves complete remission in a synovial sarcoma model

Synovial sarcomas are rare tumors arising in adolescents and young adults. The prognosis for advanced disease is poor, with an overall survival of 12‐18 months. Frizzled homolog 10 (FZD10) is overexpressed in most synovial sarcomas, making it a promising therapeutic target. The results of a phase 1 trial of β‐radioimmunotherapy (RIT) with the ⁹⁰Y‐labeled anti‐FZD10 antibody OTSA101 revealed a need for improved efficacy. The present study evaluated the potential of α‐RIT with OTSA101 labeled with the α‐emitter ²²⁵Ac. Competitive inhibition and cell binding assays showed that specific binding of ²²⁵Ac‐labeled OTSA101 to SYO‐1 synovial sarcoma cells was comparable to that of the imaging agent ¹¹¹In‐labeled OTSA101. Biodistribution studies showed high uptake in SYO‐1 tumors and low uptake in normal organs, except for blood. Dosimetric studies showed that the biologically effective dose (BED) of ²²⁵Ac‐labeled OTSA101 for tumors was 7.8 Bd higher than that of ⁹⁰Y‐labeled OTSA101. ⁹⁰Y‐ and ²²⁵Ac‐labeled OTSA101 decreased tumor volume and prolonged survival. ²²⁵Ac‐labeled OTSA101 achieved a complete response in 60% of mice, and no recurrence was observed. ²²⁵Ac‐labeled OTSA101 induced a larger amount of necrosis and apoptosis than ⁹⁰Y‐labeled OTSA101, although the cell proliferation decrease was comparable. The BED for normal organs and tissues was tolerable; no treatment‐related mortality or obvious toxicity, except for temporary body weight loss, was observed. ²²⁵Ac‐labeled OTSA101 provided a high BED for tumors and achieved a 60% complete response in the synovial sarcoma mouse model SYO‐1. RIT with ²²⁵Ac‐labeled OTSA101 is a promising therapeutic option for synovial sarcoma.

GPCRs: The most promiscuous druggable receptor of the mankind

All physiological events in living organisms originated as specific chemical/biochemical signals on the cell surface and transmitted into the cytoplasm. This signal is translated within milliseconds-hours to a specific and unique order required to maintain optimum performance and homeostasis of living organisms. Examples of daily biological functions include neuronal communication and neurotransmission in the process of learning and memory, secretion (hormones, sweat, and saliva), muscle contraction, cellular growth, differentiation and migration during wound healing, and immunity to fight infections. Among the different transducers for such life-dependent signals is the large family of G protein-coupled receptors (GPCRs). GPCRs constitute roughly 800 genes, corresponding to 2% of the human genome. While GPCRs control a plethora of pathophysiological disorders, only approximately one-third of GPCR families have been deorphanized and characterized. Recent drug data show that around 40% of the recommended drugs available in the market target mainly GPCRs. In this review, we presented how such system signals, either through G protein or via other players, independent of G protein, function within the biological system. We also discussed drugs in the market or clinical trials targeting mainly GPCRs in various diseases, including cancer.

MicroRNA-135a-induced formation of CD133+ subpopulation with cancer stem cell properties in cervical cancer

Cancer stem cells (CSCs) play significant roles in tumor initiation. MicroRNA-135a (miR-135a) induced the formation of a CD133+ subpopulation from a human papillomavirus-immortalized cervical epithelial cell line. Compared with the CD133- cells, the CD133+ cells expressed higher levels of miR-135a and OCT4, exhibited significantly higher tumorsphere forming capacity and the time required for tumorsphere formation was shortened in the second generation. Serum induction suppressed the expression of CD133, OCT4 and miR-135a, but increased expression of involucrin in the miR-135a-induced CD133+ cells. The miR-135a-induced CD133+ cells were tumorigenic in a limiting dilution approach in vivo. The cells expressed significantly higher level of active β-catenin and OCT4 than the CD133- counterpart. Wnt3a enhanced the expression of OCT4 and CD133 in cervical cancer cells but failed to enhance CD133 transcription in normal cervical cells. Wnt3a stimulation also increased tumorsphere size and self-renewal of miR-135a-induced CD133+ subpopulation. Wnt/β-catenin inhibition suppressed tumorsphere formation while Wnt3a partially nullified the inhibitory effect. Taken together, miR-135a induced the formation of a subpopulation of cells with CSC properties both in vitro and in vivo and the Wnt/β-catenin signaling pathway is essential to maintain its tumorigenicity.

Molecular subtypes based on DNA methylation predict prognosis in lung squamous cell carcinoma

BACKGROUND

Due to tumor heterogeneity, the diagnosis, treatment, and prognosis of patients with lung squamous cell carcinoma (LUSC) are difficult. DNA methylation is an important regulator of gene expression, which may help the diagnosis and therapy of patients with LUSC.

METHODS

In this study, we collected the clinical information of LUSC patients in the Cancer Genome Atlas (TCGA) database and the relevant methylated sequences of the University of California Santa Cruz (UCSC) database to construct methylated subtypes and performed prognostic analysis.

RESULTS

Nine hundred sixty-five potential independent prognosis methylation sites were finally identified and the genes were identified. Based on consensus clustering analysis, seven subtypes were identified by using 965 CpG sites and corresponding survival curves were plotted. The prognostic analysis model was constructed according to the methylation sites' information of the subtype with the best prognosis. Internal and external verifications were used to evaluate the prediction model.

CONCLUSIONS

Models based on differences in DNA methylation levels may help to classify the molecular subtypes of LUSC patients, and provide more individualized treatment recommendations and prognostic assessments for different clinical subtypes. GNAS, FZD2, FZD10 are the core three genes that may be related to the prognosis of LUSC patients.

Role of microRNAs in epidermal growth factor receptor signaling pathway in cervical cancer

Cervical cancer is one of the most common disorders in females all around the world. Similar to other types of cancer, several signaling pathways are demonstrated to be involved in the progression of this cancer including ERK/MAPK, PI3K/AKT, apoptotic signaling pathways, Wnt, and epidermal growth factor receptor (EGFR). Various microRNAs (miRNAs) and their target genes involved in cervical cancer have been extracted from the kinds of literature of Scopus, Pubmed and Google scholar databases. Regarding the targets, some of them were found to belong in EGFR signaling pathways. The regulation patterns of these miRNA are different in cervical cancer; however, their main aim is to trigger EGFR signaling to proceed with cancer. Moreover, several predicted miRNAs were found to have some interactions with the differentially expressed genes of cervical cancer which are the members of the EGFR signaling pathway by using miRWalk 3.0 (https://mirwalk.umm.uni-heidelberg.de/) and TargetScan 7.1 (https://www.targetscan.org/vert_71/). Also, the microarray data were obtained from the NCBI-Gene Expression Omnibus (GEO) datasets of cervical cancer. In the present review, we highlight the miRNAs involved in cervical cancer and the role of their targets in the EGFR signaling pathway. Furthermore, some predicted miRNAs were the candidate to target EGFR signaling pathway members differentially expressed in cervical cancer samples compared to normal samples.

The Role of Wnt Signalling in Chronic Kidney Disease (CKD)

Chronic kidney disease (CKD) encompasses a group of diverse diseases that are associated with accumulating kidney damage and a decline in glomerular filtration rate (GFR). These conditions can be of an acquired or genetic nature and, in many cases, interactions between genetics and the environment also play a role in disease manifestation and severity. In this review, we focus on genetically inherited chronic kidney diseases and dissect the links between canonical and non-canonical Wnt signalling, and this umbrella of conditions that result in kidney damage. Most of the current evidence on the role of Wnt signalling in CKD is gathered from studies in polycystic kidney disease (PKD) and nephronophthisis (NPHP) and reveals the involvement of β-catenin. Nevertheless, recent findings have also linked planar cell polarity (PCP) signalling to CKD, with further studies being required to fully understand the links and molecular mechanisms.

Genomic testing, tumor microenvironment and targeted therapy of Hedgehog-related human cancers

Hedgehog signals are transduced through Patched receptors to the Smoothened (SMO)-SUFU-GLI and SMO-Gi-RhoA signaling cascades. MTOR-S6K1 and MEK-ERK signals are also transduced to GLI activators through post-translational modifications. The GLI transcription network up-regulates target genes, such as BCL2, FOXA2, FOXE1, FOXF1, FOXL1, FOXM1, GLI1, HHIP, PTCH1 and WNT2B, in a cellular context-dependent manner. Aberrant Hedgehog signaling in tumor cells leads to self-renewal, survival, proliferation and invasion. Paracrine Hedgehog signaling in the tumor microenvironment (TME), which harbors cancer-associated fibroblasts, leads to angiogenesis, fibrosis, immune evasion and neuropathic pain. Hedgehog-related genetic alterations occur frequently in basal cell carcinoma (BCC) (85%) and Sonic Hedgehog (SHH)-subgroup medulloblastoma (87%) and less frequently in breast cancer, colorectal cancer, gastric cancer, pancreatic cancer, non-small-cell lung cancer (NSCLC) and ovarian cancer. Among investigational SMO inhibitors, vismodegib and sonidegib are approved for the treatment of patients with BCC, and glasdegib is approved for the treatment of patients with acute myeloid leukemia (AML). Resistance to SMO inhibitors is caused by acquired SMO mutations, SUFU deletions, GLI2 amplification, other by-passing mechanisms of GLI activation and WNT/β-catenin signaling activation. GLI-DNA-interaction inhibitors (glabrescione B and GANT61), GLI2 destabilizers (arsenic trioxide and pirfenidone) and a GLI-deacetylation inhibitor (4SC-202) were shown to block GLI-dependent transcription and tumorigenesis in preclinical studies. By contrast, SMO inhibitors can remodel the immunosuppressive TME that is dominated by M2-like tumor-associated macrophages (M2-TAMs), myeloid-derived suppressor cells and regulatory T cells, and thus, a Phase I/II clinical trial of the immune checkpoint inhibitor pembrolizumab with or without vismodegib in BCC patients is ongoing.

α-particle therapy for synovial sarcoma in the mouse using an astatine-211-labeled antibody against frizzled homolog 10

Synovial sarcoma (SS) is a rare yet refractory soft‐tissue sarcoma that predominantly affects young adults. We show in a mouse model that radioimmunotherapy (RIT) with an α‐particle emitting anti‐Frizzled homolog 10 (FZD10) antibody, synthesized using the α‐emitter radionuclide astatine‐211 (²¹¹At‐OTSA101), suppresses the growth of SS xenografts more efficiently than the corresponding β‐particle emitting anti‐FZD10 antibody conjugated with the β‐emitter yettrium‐90 (⁹⁰Y‐OTSA101). In biodistribution analysis, ²¹¹At was increased in the SS xenografts but decreased in other tissues up to 1 day after injection as time proceeded, albeit with a relatively higher uptake in the stomach. Single ²¹¹At‐OTSA101 doses of 25 and 50 μCi significantly suppressed SS tumor growth in vivo, whereas a 50‐μCi dose of ⁹⁰Y‐OTSA101 was needed to achieve this. Importantly, 50 μCi of ²¹¹At‐OTSA101 suppressed tumor growth immediately after injection, whereas this effect required several days in the case of ⁹⁰Y‐OTSA101. Both radiolabeled antibodies at the 50‐μCi dosage level significantly prolonged survival. Histopathologically, severe cellular damage accompanied by massive cell death was evident in the SS xenografts at even 1 day after the ²¹¹At‐OTSA101 injection, but these effects were relatively milder with ⁹⁰Y‐OTSA101 at the same timepoint, even though the absorbed doses were comparable (3.3 and 3.0 Gy, respectively). We conclude that α‐particle RIT with ²¹¹At‐OTSA101 is a potential new therapeutic option for SS.

A fusion-protein approach enabling mammalian cell production of tumor targeting protein domains for therapeutic development

A single chain Fv fragment (scFv) is a fusion of the variable regions of heavy (VH ) and light (VL ) chains of immunoglobulins. They are important elements of chimeric antigen receptors for cancer therapy. We sought to produce a panel of 16 extracellular protein domains of tumor markers for use in scFv yeast library screenings. A series of vectors comprising various combinations of expression elements was made, but expression was unpredictable and more than half of the protein domains could not be produced using any of the constructs. Here we describe a novel fusion expression system based on mouse TEM7 (tumor endothelial marker 7), which could facilitate protein expression. With this approach we could produce all but one of the tumor marker domains that could not otherwise be expressed. In addition, we demonstrated that the tumor associated antigen hFZD10 produced as a fusion protein with mTEM7 could be used to enrich scFv antibodies from a yeast display library. Collectively our study demonstrates the potential of specific fusion proteins based on mTEM7 in enabling mammalian cell production of tumor targeting protein domains for therapeutic development.

A phase 2 study of vorinostat in locally advanced, recurrent, or metastatic adenoid cystic carcinoma

Purpose

Vorinostat is a histone deacetylase inhibitor (HDACi). Based on a confirmed partial response (PR) in an adenoid cystic carcinoma (ACC) patient treated with vorinostat in a prior phase 1 trial, we initiated this phase 2 trial. Methods: Vorinostat was administered orally 400 mg daily, 28 day cycles. The primary objective was to evaluate response rate (RR). Exploratory studies included whole exome sequencing (WES) of selected patients.

Results

Thirty patients were enrolled. Median age of patients was 53 years (range 21–73). Median number of cycles was 5 (range 1-66). Lymphopenia (n = 5), hypertension (n = 3), oral pain (n = 2), thromboembolic events (n = 2) and fatigue (n = 2) were the only grade 3 adverse events (AEs) that occurred in more than 1 patient. Eleven patients were dose reduced secondary to drug-related AEs. Two patients had a partial response (PR), with response durations of 53 and 7.2 months. One patient had a minor response with a decrease in ascites (for 19 cycles). Stable disease was the best response in 27 patients. Targeted and WES of 8 patients in this trial identified mutations in chromatin remodeling genes highlighting the role of the epigenome in ACC. Conclusion: Vorinostat demonstrated efficacy in patients with ACC supporting the inclusion of HDACi in future studies to treat ACC.

Frizzled-10 and cancer progression: Is it a new prognostic marker?

Frizzled (FZD) proteins, a family of Wnt receptors, are involved in carcinogenesis in different organs. One interesting FZD protein is FZD-10 highly expressed in embryogenesis but completely absent in the membrane or cytosol of healthy proliferated cells. We studied in detail the expression level and the location of Frizzled-10 protein in different cancerous tissues, such as colon, melanoma and gastric cancer and in function of different staging of the tumor and in metastases. We observed a correlation between cancer evolution and FZD-10 expression, and localization of protein during carcinogenesis. In colon, we have an increase of cytoplasmic FZD-10 expression from hyperplastic mucosa to metastatic tissues, while the amount in the nucleus decreases significantly in T3 and T4 staging tumors as well as in metastases. In melanoma and gastric cancer, we observed the opposite trend of FZD-10 protein in the cytosol but both show a decrease in the T3 and T4 stage of the tumor and in metastases. However, the decrease is less prominent in gastric cancer.

Our findings indicate an important role of FZD-10 in tumor progression especially in the later stages of tumor. The nuclear expression of FZD-10 or its absence can give a new tool for tumor staging to pathologists. For target therapy, at least for colon cancer, the high presence of FZD-10 in the later stages of tumor progression and the absence in healthy tissue present a promising new approach.

Molecular genetics and targeted therapy of WNT-related human diseases (Review)

Canonical WNT signaling through Frizzled and LRP5/6 receptors is transduced to the WNT/β-catenin and WNT/stabilization of proteins (STOP) signaling cascades to regulate cell fate and proliferation, whereas non-canonical WNT signaling through Frizzled or ROR receptors is transduced to the WNT/planar cell polarity (PCP), WNT/G protein-coupled receptor (GPCR) and WNT/receptor tyrosine kinase (RTK) signaling cascades to regulate cytoskeletal dynamics and directional cell movement. WNT/β-catenin signaling cascade crosstalks with RTK/SRK and GPCR-cAMP-PKA signaling cascades to regulate β-catenin phosphorylation and β-catenin-dependent transcription. Germline mutations in WNT signaling molecules cause hereditary colorectal cancer, bone diseases, exudative vitreoretinopathy, intellectual disability syndrome and PCP-related diseases. APC or CTNNB1 mutations in colorectal, endometrial and prostate cancers activate the WNT/β-catenin signaling cascade. RNF43, ZNRF3, RSPO2 or RSPO3 alterations in breast, colorectal, gastric, pancreatic and other cancers activate the WNT/β-catenin, WNT/STOP and other WNT signaling cascades. ROR1 upregulation in B-cell leukemia and solid tumors and ROR2 upregulation in melanoma induce invasion, metastasis and therapeutic resistance through Rho-ROCK, Rac-JNK, PI3K-AKT and YAP signaling activation. WNT signaling in cancer, stromal and immune cells dynamically orchestrate immune evasion and antitumor immunity in a cell context-dependent manner. Porcupine (PORCN), RSPO3, WNT2B, FZD5, FZD10, ROR1, tankyrase and β-catenin are targets of anti-WNT signaling therapy, and ETC-159, LGK974, OMP-18R5 (vantictumab), OMP-54F28 (ipafricept), OMP-131R10 (rosmantuzumab), PRI-724 and UC-961 (cirmtuzumab) are in clinical trials for cancer patients. Different classes of anti-WNT signaling therapeutics are necessary for the treatment of APC/CTNNB1-, RNF43/ZNRF3/RSPO2/RSPO3- and ROR1-types of human cancers. By contrast, Dickkopf-related protein 1 (DKK1), SOST and glycogen synthase kinase 3β (GSK3β) are targets of pro-WNT signaling therapy, and anti-DKK1 (BHQ880 and DKN-01) and anti-SOST (blosozumab, BPS804 and romosozumab) monoclonal antibodies are being tested in clinical trials for cancer patients and osteoporotic post-menopausal women. WNT-targeting therapeutics have also been applied as reagents for in vitro stem-cell processing in the field of regenerative medicine.

Methylome analysis of extreme chemoresponsive patients identifies novel markers of platinum sensitivity in high-grade serous ovarian cancer

BACKGROUND

Despite an early response to platinum-based chemotherapy in advanced stage high-grade serous ovarian cancer (HGSOC), the majority of patients will relapse with drug-resistant disease. Aberrant epigenetic alterations like DNA methylation are common in HGSOC. Differences in DNA methylation are associated with chemoresponse in these patients. The objective of this study was to identify and validate novel epigenetic markers of chemoresponse using genome-wide analysis of DNA methylation in extreme chemoresponsive HGSOC patients.

METHODS

Genome-wide next-generation sequencing was performed on methylation-enriched tumor DNA of two HGSOC patient groups with residual disease, extreme responders (≥18 months progression-free survival (PFS), n = 8) and non-responders (≤6 months PFS, n = 10) to platinum-based chemotherapy. DNA methylation and expression data of the same patients were integrated to create a gene list. Genes were validated on an independent cohort of extreme responders (n = 21) and non-responders (n = 31) using pyrosequencing and qRT-PCR. In silico validation was performed using publicly available DNA methylation (n = 91) and expression (n = 208) datasets of unselected advanced stage HGSOC patients. Functional validation of FZD10 on chemosensitivity was carried out in ovarian cancer cell lines using siRNA-mediated silencing.

RESULTS

Integrated genome-wide methylome and expression analysis identified 45 significantly differentially methylated and expressed genes between two chemoresponse groups. Four genes FZD10, FAM83A, MYO18B, and MKX were successfully validated in an external set of extreme chemoresponsive HGSOC patients. High FZD10 and MKX methylation were related with extreme responders and high FAM83A and MYO18B methylation with non-responders. In publicly available advanced stage HGSOC datasets, FZD10 and MKX methylation levels were associated with PFS. High FZD10 methylation was strongly associated with improved PFS in univariate analysis (hazard ratio (HR) = 0.43; 95% CI, 0.27-0.71; P = 0.001) and multivariate analysis (HR = 0.39; 95% CI, 0.23-0.65; P = 0.003). Consistently, low FZD10 expression was associated with improved PFS (HR = 1.36; 95% CI, 0.99-1.88; P = 0.058). FZD10 silencing caused significant sensitization towards cisplatin treatment in survival assays and apoptosis assays.

CONCLUSIONS

By applying genome-wide integrated methylome analysis on extreme chemoresponsive HGSOC patients, we identified novel clinically relevant, epigenetically-regulated markers of platinum-sensitivity in HGSOC patients. The clinical potential of these markers in predictive and therapeutic approaches has to be further validated in prospective studies.

Pharmacological interventions in the Wnt pathway: inhibition of Wnt secretion versus disrupting the protein-protein interfaces of nuclear factors

Mutations in components of the Wnt pathways are a frequent cause of many human diseases, particularly cancer. Despite the fact that a causative link between aberrant Wnt signalling and many types of human cancers was established more than a decade ago, no Wnt signalling inhibitors have made it into the clinic so far. One reason for this is that no pathway-specific kinase is known. Additionally, targeting the protein-protein interactions needed to transduce the signal has not met with success so far. Complicating the search for and use of inhibitors is the complexity of the cascades triggered by the Wnts and their paramount biological importance. Wnt/β-catenin signalling is involved in virtually all aspects of embryonic development and in the control of the homeostasis of adult tissues. Encouragingly, however, in recent years, first successes with Wnt-pathway inhibitors have been reported in mouse models of disease. In this review, we summarize possible roads to follow during the quest to pharmacologically modulate the Wnt signalling pathway in cancer.

LINKED ARTICLES

This article is part of a themed section on WNT Signalling: Mechanisms and Therapeutic Opportunities. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.24/issuetoc.

FZD10-Gα13 signalling axis points to a role of FZD10 in CNS angiogenesis

Among the 10 Frizzled (FZD) isoforms belonging to the Class F of G protein-coupled receptors (GPCRs), FZD₁₀ remains the most enigmatic. FZD₁₀ shows homology to FZD₄ and FZD₉ and was previously implicated in both β-catenin-dependent and -independent signalling. In normal tissue, FZD₁₀ levels are generally very low; however, its upregulation in synovial carcinoma has attracted some attention for therapy. Our findings identify FZD₁₀ as a receptor interacting with and signalling through the heterotrimeric G protein Gα₁₃ but not Gα_12, Gα_i1, Gα_oA, Gα_s, or Gα_q. Stimulation with the FZD agonist WNT induced the dissociation of the Gα₁₃ protein from FZD₁₀, and led to global Gα_12/13-dependent cell changes assessed by dynamic mass redistribution measurements. Furthermore, we show that FZD₁₀ mediates Gα_12/13 activation-dependent induction of YAP/TAZ transcriptional activity. In addition, we show a distinct expression of FZD₁₀ in embryonic CNS endothelial cells at E11.5-E14.5. Given the well-known importance of Gα₁₃ signalling for the development of the vascular system, the selective expression of FZD₁₀ in brain vascular endothelial cells points at a potential role of FZD₁₀-Gα₁₃ signalling in CNS angiogenesis.

Frizzled Receptors in Development and Disease

Frizzled proteins are the principal receptors for the Wnt family of ligands. They mediate canonical Wnt signaling together with Lrp5 and Lrp6 coreceptors. In conjunction with Celsr, Vangl, and a small number of additional membrane and membrane-associated proteins, they also play a central role in tissue polarity/planar cell polarity (PCP) signaling. Targeted mutations in 9 of the 10 mammalian Frizzled genes have revealed their roles in an extraordinarily diverse set of developmental and homeostatic processes, including morphogenetic movements responsible for palate, ventricular septum, ocular furrow, and neural tube closure; survival of thalamic neurons; bone formation; central nervous system (CNS) angiogenesis and blood-brain barrier formation and maintenance; and a wide variety of processes that orient subcellular, cellular, and multicellular structures relative to the body axes. The last group likely reflects the mammalian equivalent of tissue polarity/PCP signaling, as defined in Drosophila, and it includes CNS axon guidance, hair follicle and tongue papilla orientation, and inner ear sensory hair bundle orientation. Frizzled receptors are ubiquitous among multicellular animals and, with other signaling molecules, they very likely evolved to permit the development of the complex tissue architectures that provide multicellular animals with their enormous selective advantage.

Gastric cancer cell proliferation is suppressed by frizzled-2 short hairpin RNA

In order to identify novel targets for the molecular therapy of gastric cancer (GC), we investigated the mRNA and protein expression of frizzled-2 (Fz2), a Wnt signaling pathway receptor. Reverse-transcriptase polymerase chain reaction (PCR) amplification was utilized to determine the expression patterns of Fz genes in normal stomach and in the GC cell lines MKN45 and MKN74. Immunostaining was performed on surgical specimens of GC using an antibody against Fz2. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay was performed on MKN45 cells and MKN74 cells transfected with Fz2 short-hairpin (sh) RNA. Cell motility was analyzed by scratch assay following Fz2 shRNA. Real-time quantitative PCR was performed to analyze the expression levels of cyclin D1 and matrix metallopeptidase 9 (MMP-9). Fz1, 3, 6 and 8 were expressed in normal stomach, and in MKN45 and MKN74 cells. Fz2 was expressed in normal stomach and in MKN45, but not in MKN74 cells. Well-differentiated GC tissue was weakly positive for Fz2 in cell membranes. Fz2 was positive in both the cell membrane and cytoplasm of GC tissues of moderately differentiated and poorly differentiated adenocarcinoma. Signet ring cells were positive for cytoplasmic Fz2. Proliferation of MKN45 and MKN74 cells was suppressed by Fz2 shRNA, and a scratch assay demonstrated that Fz2 shRNA suppressed also MKN45 and MKN74 cell motility. Furthermore, Fz2 shRNA application led to downregulated mRNA expression of both cyclin D1 and MMP-9. Fz2, 3, 6 and 8 were expressed in normal stomach, and in MKN45 and MKN74 GC cells. Fz2 shRNA suppressed cell proliferation and motility of MKN45 and MKN74 cells, and downregulated cyclin D1 and MMP-9 expression in these GC cell lines.

BRMS1L suppresses breast cancer metastasis by inducing epigenetic silence of FZD10

BRMS1L (breast cancer metastasis suppressor 1 like, BRMS1-like) is a component of Sin3A-histone deacetylase (HDAC) co-repressor complex that suppresses target gene transcription. Here we show that reduced BRMS1L in breast cancer tissues is associated with metastasis and poor patient survival. Functionally, BRMS1L inhibits breast cancer cells migration and invasion by inhibiting epithelial-mesenchymal transition. These effects are mediated by epigenetic silencing of FZD10, a receptor for Wnt signalling, through HDAC1 recruitment and histone H3K9 deacetylation at the promoter. Consequently, BRMS1L-induced FZD10 silencing inhibits aberrant activation of WNT3-FZD10-β-catenin signalling. Furthermore, BRMS1L is a target of miR-106b and miR-106b upregulation leads to BRMS1L reduction in breast cancer cells. RNA interference-mediated silencing of BRMS1L expression promotes metastasis of breast cancer xenografts in immunocompromised mice, whereas ectopic BRMS1L expression inhibits metastasis. Therefore, BRMS1L provides an epigenetic regulation of Wnt signalling in breast cancer cells and acts as a breast cancer metastasis suppressor.

Frizzled homolog proteins, microRNAs and Wnt signaling in cancer

Wnt signaling pathways play important roles in tumorigenesis and are initiated by binding of Wnt to various receptors including frizzleds (FZDs). FZDs are one of several families of receptors comprised of FZD/LRP/ROR2/RYK in the Wnt signaling pathway. Expression of some FZD receptors are up regulated, thereby activating the Wnt signaling pathway and is correlated with cancer malignancy and patient outcomes (recurrence and survival) in many cancers. The FZD family contains ten genes in humans and their function has not been completely examined including the regulatory mechanisms of FZD genes in cancer. Knockdown of FZDs may suppress the Wnt signaling pathway resulting in decreased cell growth, invasion, motility and metastasis of cancer cells. Recently a number of microRNAs (miRNAs) have been identified and reported to be important in several cancers. MiRNAs regulate target gene expression at both the transcription and translation levels. The study of miRNA is a newly emerging field and promises to be helpful in understanding the pathogenesis of FZDs in cancer. In addition, miRNAs may be useful in regulating FZDs in cancer cells. Therefore, the aim of this review is to discuss current knowledge of the functional mechanisms of FZDs in cancer, including regulation by miRNAs and the potential for possible use of miRNAs and FZDs in future clinical applications.

Comprehensive genomic analysis of a BRCA2 deficient human pancreatic cancer

Capan-1 is a well-characterised BRCA2-deficient human cell line isolated from a liver metastasis of a pancreatic adenocarcinoma. Here we report a genome-wide assessment of structural variations and high-depth exome characterization of single nucleotide variants and small insertion/deletions in Capan-1. To identify potential somatic and tumour-associated variations in the absence of a matched-normal cell line, we devised a novel method based on the analysis of HapMap samples. We demonstrate that Capan-1 has one of the most rearranged genomes sequenced to date. Furthermore, small insertions and deletions are detected more frequently in the context of short sequence repeats than in other genomes. We also identify a number of novel mutations that may represent genetic changes that have contributed to tumour progression. These data provide insight into the genomic effects of loss of BRCA2 function.

Identification of human placenta-derived mesenchymal stem cells involved in re-endothelialization

Human placenta is an attractive source of mesenchymal stem cells (MSC) for regenerative medicine. The cell surface markers expressed on MSC have been proposed as useful tools for the isolation of MSC from other cell populations. However, the correlation between the expression of MSC markers and the ability to support tissue regeneration in vivo has not been well examined. Here, we established several MSC lines from human placenta and examined the expression of their cell surface markers and their ability to differentiate toward mesenchymal cell lineages. We found that the expression of CD349/frizzled-9, a receptor for Wnt ligands, was positive in placenta-derived MSC. So, we isolated CD349-negative and -positive fractions from an MSC line and examined how successfully cell engraftment repaired fractured bone and recovered blood flow in ischemic regions using mouse models. CD349-negative and -positive cells displayed a similar expression pattern of cell surface markers and facilitated the repair of fractured bone in transplantation experiments in mice. Interestingly, CD349-negative, but not CD349-positive cells, showed significant effects on recovering blood flow following vascular occlusion. We found that induction of PDGFβ and bFGF mRNAs by hypoxia was greater in CD349-negative cells than in CD349-positive cells while the expression of VEGF was not significantly different in CD349-negative and CD349-positive cells. These findings suggest the possibility that CD349 could be utilized as a specialized marker for MSC isolation for re-endothelialization.

Frizzled-10 promotes sensory neuron development in Xenopus embryos

Formation of the vertebrate nervous system requires coordinated cell-cell interactions, intracellular signalling events, gene transcription, and morphogenetic cell movements. Wnt signalling has been involved in regulating a wide variety of biological processes such as embryonic patterning, cell proliferation, cell polarity, motility, and the specification of cell fate. Wnt ligands associate with their receptors, members of the frizzled family (Fz). In Xenopus, five members of the frizzled family are expressed in the early nervous system. We have investigated the role of Xenopus frizzled-10 (Fz10) in neural development. We show that Fz10 is expressed in the dorsal neural ectoderm and neural folds in the region where primary sensory neurons develop. Fz10 mediates canonical Wnt signalling and interacts with Wnt1 and Wnt8 but not Wnt3a as shown in synergy assays. We find that Fz10 is required for the late stages of sensory neuron differentiation. Overexpression of Fz10 in Xenopus leads to an increase in the number of sensory neurons. Loss of Fz10 function using morpholinos inhibits the development of sensory neurons in Xenopus at later stages of neurogenesis and this can be rescued by co-injection of modified Fz10B and beta-catenin. In mouse P19 cells induced by retinoic acid to undergo neural differentiation, overexpression of Xenopus Fz10 leads to an increase in the number of neurons generated while siRNA knockdown of endogenous mouse Fz10 inhibits neurogenesis. Thus we propose Fz10 mediates Wnt1 signalling to determine sensory neural differentiation in Xenopus in vivo and in mouse cell culture.

Radioimmunotherapy of solid tumors targeting a cell-surface protein, FZD10: therapeutic efficacy largely depends on radiosensitivity

OBJECTIVE

Frizzled homolog 10 (FZD10) is expressed at high levels on the cell surface of almost all synovial sarcoma tissues, but is absent in most normal organs. In a previous study, yttrium-90 ((90)Y)-labeled anti-FZD10 antibody (MAb 92-13) showed considerable therapeutic efficacy in synovial sarcoma cell-bearing mice. The purpose of the present study was to elucidate the factors associated with this therapeutic efficacy of (90)Y-MAb 92-13.

METHODS

FZD10 expression levels of SYO-1 (FZD10-overexpressing synovial sarcoma cell line) and DLD-1/FZD10 (FZD10-transfected DLD-1 cell) were determined by the cell binding assay, and their radiosensitivity was evaluated by incubation with (90)Y-MAb 92-13 in vitro. Biodistribution study of indium-111 ((111)In)-MAb 92-13 was performed in SYO-1 and DLD-1/FZD10 tumor-bearing mice. For therapeutic studies, SYO-1 and DLD-1/FZD10 tumor-bearing mice were treated with (90)Y-MAb 92-13 (100, 150, and 200 muCi), after which the change in tumor volume was measured. Immunohistochemical staining was performed on the excised tumor.

RESULTS

Expression level of FZD10 on DLD-1/FZD10 was much greater than that on SYO-1. The accumulation of (111)In-MAb 92-13 was much higher in DLD-1/FZD10 tumor-bearing mice than in SYO-1 tumor-bearing mice (49.0 +/- 4.2 and 22.0 +/- 4.5% ID/g, respectively, at 48 h after administration). In SYO-1 tumor, substantial tumor size reduction was observed in all mice treated with (90)Y-MAb 92-13 (tumor volume decreased to less than 0.1 cm(3) at 11 days after treatment) and tumor regrowth was not observed in most of them. In contrast, only slow progression was observed in DLD-1/FZD10 tumor. When incubated with (90)Y-MAb 92-13, high radioactivity was needed to damage DLD-1/FZD10. Immunohistochemical study indicated apoptosis of SYO-1 tumor.

CONCLUSIONS

The therapeutic efficacy of RIT seems to largely depend on the tumor radiosensitivity.

Activation of the non-canonical Dvl-Rac1-JNK pathway by Frizzled homologue 10 in human synovial sarcoma

We previously reported that Frizzled homologue 10 (FZD10), a member of the Wnt signal receptor family, was highly and specifically upregulated in synovial sarcoma and played critical roles in its cell survival and growth. We here report a possible molecular mechanism of the FZD10 signaling in synovial sarcoma cells. We found a significant enhancement of phosphorylation of the Dishevelled (Dvl)2/Dvl3 complex as well as activation of the Rac1-JNK cascade in synovial sarcoma cells in which FZD10 was overexpressed. Activation of the FZD10-Dvls-Rac1 pathway induced lamellipodia formation and enhanced anchorage-independent cell growth cells. FZD10 overexpression also caused the destruction of the actin cytoskeleton structure, probably through the downregulation of the RhoA activity. Our results have strongly implied that FZD10 transactivation causes the activation of the non-canonical Dvl-Rac1-JNK pathway and plays critical roles in the development/progression of synovial sarcomas.

Expression of Frizzled10 in mouse central nervous system

Frizzled transmembrane proteins (Fzd) are receptors of Wnts, and they play key roles during central nervous system (CNS) development in vertebrates. Here we report the expression pattern of Frizzled10 in mouse CNS from embryonic stages to adulthood. Frizzled10 is expressed strongly at embryonic days E8.5 and E9.5 in the neural tube and tail bud. At E10.5, Frizzled10 is expressed in the forebrain vesicle, the fourth ventricle and the dorsal spinal cord. From E12.5 to E16.5, Frizzled10 expression is mainly observed in the cortical hem/fimbria, the neuroepithelium of the third ventricular zone, midbrain, developing cerebellum, and dorsal spinal cord. At P0, with the exception of expression in the fimbria, Frizzled10 mRNA expression is limited to specific nuclei including the ventral posterior thalamic nucleus (VP) and the dorsal lateral geniculate nucleus (DLG) in the developing thalamus as well as in the proliferative ventricular zone of the developing cerebellum. From P20 to adult, Frizzled10 mRNA is detected only in the internal capsule (ic). Our data show that expression of Frizzled10 is very strong during embryonic development of the CNS and suggest that Frizzled10 may play an essential role in spatial and temporal regulation during neural development.

Second hit in cervical carcinogenesis process: involvement of wnt/beta catenin pathway

The Human papillomavirus plays an important role in the initiation and progression of cervical cancer. However, it is a necessary but not sufficient cause to develop invasive carcinoma; hence, other factors are required in the pathogenesis of this malignancy. In this review we explore the hypothesis of the deregulation of wnt/beta-catenin signaling pathway as a "second hit" required to develop cervical cancer.

Structural diversity of G protein-coupled receptors and significance for drug discovery

G protein-coupled receptors (GPCRs) are the largest family of membrane-bound receptors and also the targets of many drugs. Understanding of the functional significance of the wide structural diversity of GPCRs has been aided considerably in recent years by the sequencing of the human genome and by structural studies, and has important implications for the future therapeutic potential of targeting this receptor family. This article aims to provide a comprehensive overview of the five main human GPCR families--Rhodopsin, Secretin, Adhesion, Glutamate and Frizzled/Taste2--with a focus on gene repertoire, general ligand preference, common and unique structural features, and the potential for future drug discovery.

Radioimmunotherapy of human synovial sarcoma using a monoclonal antibody against FZD10

We previously reported Frizzled homolog 10 (FZD10), a member of the Frizzled family, to be a promising therapeutic target for synovial sarcomas. In this report, we established a murine monoclonal antibody (MAb), namely, MAb 92-13 that had specific binding activity against native FZD10 product expressed in synovial sarcoma cell lines. Subsequent immunohistochemical analyses with the MAb 92-13 confirmed an absence or hardly detectable level of FZD10 protein in any normal human organs. We confirmed the specific binding activity of this MAb in vivo after injection of fluorescent-labeled MAb i.p. or i.v. into the mice carrying synovial sarcoma xenografts by the use of the in vivo fluorescent imaging system as well as radioisotopes. Moreover, MAb 92-13 was effectively internalized into the synovial sarcoma cells after its binding to FZD10 on the cell surface. A single i.v. injection of the Yttrium-90 ((90)Y)-MAb 92-13 drastically suppressed tumor growth of synovial sarcoma in mice without any severe toxicity. Median time to tumor progression was 58 days for mice treated with (90)Y-MAb 92-13 and 9 days for mice treated with non-labeled antibody control or untreated mice (difference = 49 days; P = 7 x 10(-5)). This result indicates that MAb 92-13 could be utilized as the novel treatment modality for synovial sarcoma and other FZD10-positive tumors.

Networking of WNT, FGF, Notch, BMP, and Hedgehog signaling pathways during carcinogenesis

The biological functions of some orthologs within the human genome and model-animal genomes are evolutionarily conserved, but those of others are divergent due to protein evolution and promoter evolution. Because WNT signaling molecules play key roles during embryogenesis, tissue regeneration and carcinogenesis, the author's group has carried out a human WNT-ome project for the comprehensive characterization of human genes encoding WNT signaling molecules. From 1996 to 2002, we cloned and characterized WNT2B/WNT13, WNT3, WNT3A, WNT5B, WNT6, WNT7B, WNT8A, WNT8B, WNT9A/WNT14, WNT9B/WNT14B, WNT10A, WNT10B, WNT11, FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD10, FRAT1, FRAT2, NKD1, NKD2, VANGL1, RHOU/ARHU, RHOV/ARHV, GIPC2, GIPC3, FBXW11/betaTRCP2, SOX17, TCF7L1/TCF3, and established a cDNA-PCR system for snap-shot and dynamic analyses on the WNT-transcriptome. In 2003, we identified and characterized PRICKLE1, PRICKLE2, DACT1/DAPPER1, DACT2/DAPPER2, DAAM2, and BCL9L. After completion of the human WNT-ome project, we have been working on the stem cell signaling network. WNT signals are transduced to beta-catenin, NLK, NFAT, PKC, JNK and RhoA signaling cascades. FGF20, JAG1 and DKK1 are target genes of the WNT-beta-catenin signaling cascade. Cross-talk of WNT and FGF signaling pathways potentiates beta-catenin and NFAT signaling cascades. BMP signals induce IHH upregulation in co-operation with RUNX. Hedgehog signals induce upregulation of SFRP1, JAG2 and FOXL1, and then FOXL1 induces BMP4 upregulation. The balance between WNT-FGF-Notch and BMP-Hedgehog signaling networks is important for the maintenance of homoestasis among stem and progenitor cells. Disruption of the stem cell signaling network results in pathological conditions, such as congenital diseases and cancer.

Molecular target therapy for synovial sarcoma

Although the specific chromosomal translocation and fusion gene SYT-SSX in synovial sarcoma (SS) has been identified, the molecular mechanism of its tumorigenesis is largely unknown. Recent gene-expression profiles of soft-tissue tumors using cDNA microarray demonstrated that SS has the distinct gene-expression pattern from other sarcomas and has a similar pattern to that of malignant peripheral nerve sheath tumors, indicating that the origin of SS is likely to be the neural crest cells. Through this analysis, several genes were found to be specifically upregulated in SS and considered to play an important role in the proliferation of SS cells. Among them, Frizzled homolog 10 was identified as a good candidate molecule for the development of novel therapies to treat SS patients.

Cultured interstitial cells from human heart valves express both specific skeletal muscle and non-muscle markers

Cardiac valve interstitial cells are a phenotypically diverse and dynamic population, comprising myofibroblasts, fibroblasts and smooth muscle cells. To understand how these contribute to valve function and to optimize the choice of cells for seeding tissue-engineered valves, we are fingerprinting interstitial cells from all four human heart valves for useful phenotypic markers. We have begun by selecting markers indicated as of interest from previous work on myofibroblast-like cell lines. We show that interstitial cells express a variety of skeletal muscle contractile proteins and the skeletal muscle transcription factor myogenin, but not the related factors MyoD, myf-5 and MRF4, suggesting partial activation of the muscle programme in these cells. Expression of non-muscle isoforms of creatine kinase (CK-B) and AMP deaminase (AMPD2 and AMPD3) was found in contrast to muscle-restricted isoforms. Non-muscle isoforms of alpha- and beta-tropomyosins were detected specifically in contrast to skeletal muscle-specific isoforms. Several members of the Frizzled (FZD) family of Wnt receptors were also detected. In addition, intact cusps of all four valves from pig were capable of contacting to non-receptor and receptor-mediated stimulation in vitro. We conclude that interstitial cells from human heart valves express various sarcomeric proteins, and suggest that these cells have contractile potential due to a unique pattern of expression of both muscle-specific and non-muscle isoforms of metabolic and structural proteins. This may be under the control of myogenin, activated through specific Wnt/FZD signaling. Identifying such molecular markers could prove useful for engineering allogenic non-valve cell sources for seeding the synthetic valve.

Therapeutic potential of antibodies against FZD 10, a cell-surface protein, for synovial sarcomas

Genome-wide expression profiling revealed overexpression of the gene encoding frizzled homologue 10 (FZD 10), a cell-surface receptor for molecules in the Wnt pathway, as a potential contributor to synovial sarcomas (SS). Northern blotting and immunohistochemical staining confirmed that expression levels of FZD 10 were very high in nearly all SS tumors and cell lines examined but absent in most normal organs or in some cancers arising in other tissues. Treatment of human SS cells with small-interfering RNA (siRNA) to FZD 10 decreased the amount of its product and suppressed growth of SS cells. Moreover, a polyclonal antibody specifically recognizing the extracellular domain (ECD) of FZD 10 was markedly effective in mediating ADCC against FZD 10-overexpressing synovial sarcoma cells in vitro. Injection of the antibody into SS xenografts in nude mice attenuated tumor growth, and TUNEL assays revealed clusters of apoptotic cells in antibody-treated xenografts. Taken together, these findings suggest that a humanized antibody against FZD 10 might be a promising treatment for patients with tumors that overexpress FZD 10; minimal or no adverse reactions would be expected because FZD 10 protein is not abundant in vital organs.

β-Catenin/T-cell factor-mediated transcription is modulated by cell density in human bronchial epithelial cells

The embryonic Wnt/beta-catenin ('canonical') pathway has been implicated in epithelial regeneration. To investigate the role of Wnt signal transduction in the airways, we characterised the expression of key pathway components in human bronchial epithelial cells (HBEC) and studied the influence of cell density on pathway activity, using sub-confluent cells in log-phase growth as a simple model of repairing epithelium. Primary HBEC and H292 bronchial epithelial cells were found to express TCF-4, TCF-3 and isoforms of LEF-1, transcription factors that are regulated by Wnt signalling. The cells also had the potential to respond to Wnt signalling through expression of several members of the Frizzled receptor family, including FZD-5 and -6. In confluent H292 cells, 20 mM lithium and 25% v/v Wnt-3a conditioned medium induced 4.5-fold (p = 0.008) and 1.4-fold (p = 0.006) increases in TOPflash activity, respectively. Under conditions of reduced cell density, TOPflash activity increased 1.8-fold (p = 0.002) in association with increased nuclear localisation of hypophosphorylated (active) beta-catenin and increased cell proliferation. This up-regulation in reporter activity occurred independently of EGF receptor activation and could not be recapitulated by use of low-calcium medium to disrupt cadherin-mediated cell-cell adhesion, but was associated with changes in FZD-6 expression. We conclude that reactivation of this embryonic pathway may play an important role in bronchial epithelial regeneration, and that modulation of Fzd-6 receptors may regulate Wnt signalling at confluence. Recognising that many chronic inflammatory disorders of the airways involve epithelial damage and repair, altered Wnt signalling might contribute to disease pathogenesis or progression.

Expression of Wnt, Frizzled, sFRP, and DKK genes in adult human pancreas

Wnts are important signaling molecules involved in many normal developmental processes in the human body as well as some forms of cancer. Nineteen Wnt genes are found in the human genome, as well as 10 Wnt receptor genes called Frizzled. Two coreceptors called LRP 5 and 6 are critical for Wnt signal transduction. The interaction of the Wnts with the receptors is regulated by two classes of extracellular Wnt or LRP binding proteins called sFRP and Dickkopf (DKK), which modulate Wnt signaling. We have examined the expression of all Wnt family members both in the exocrine portion and in isolated islets of adult human pancreas. RT-PCR analysis of the 1-day cultured exocrine pellet fraction from the islet isolation procedure showed that Wnt 2, 2b, 3, 4, 5a, 5b, 7a, 7b, 14, and 15 were detectable. All 10 Frizzled (Frz) receptors were expressed but only Frizzled 1, 2, 4, 5, and 6 strongly. RT-PCR performed on purified human islets revealed that Wnt 2b, 3, 4, 5a, 7b, 10a, and 14 and Frz 4, 5, and 6 were the most highly expressed. DKK 1, 3, and 4 as well as sFRP 1, 4, and 5 were expressed in the exocrine fraction. sFRP 2 and 3 were detectable but only at low levels. In situ hybridization for Frz 1-7 showed that expression colocalized with the islets of Langerhans. Together the data suggest that active Wnt signaling occurs in adult pancreas and is probably important for physiological functions.

The human Hox-bearing chromosome regions did arise by block or chromosome (or even genome) duplications

Many chromosome regions in the human genome exist in four similar copies, suggesting that the entire genome was duplicated twice in early vertebrate evolution, a concept called the 2R hypothesis. Forty-two gene families on the four Hox-bearing chromosomes were recently analyzed by others, and 32 of these were reported to have evolutionary histories incompatible with duplications concomitant with the Hox clusters, thereby contradicting the 2R hypothesis. However, we show here that nine of the families have probably been translocated to the Hox-bearing chromosomes more recently, and that three of these belong to other chromosome quartets where they actually support the 2R hypothesis. We consider 13 families too complex to shed light on the chromosome duplication hypothesis. Among the remaining 20 families, 14 display phylogenies that support or are at least consistent with the Hox-cluster duplications. Only six families seem to have other phylogenies, but these trees are highly uncertain due to shortage of sequence information. We conclude that all relevant and analyzable families support or are consistent with block/chromosome duplications and that none clearly contradicts the 2R hypothesis.

Ovulatory surges of human CG prevent hormone-induced granulosa cell tumor formation leading to the identification of tumor-associated changes in the transcriptome

Granulosa cell tumors comprise approximately 10% of ovarian tumors and, although rare, are clinically important due to their potential for malignancy and recurrence. Although their morphological features have been carefully described, the global changes in gene expression associated with their formation remain undetermined. To initiate this characterization, we used a transgenic mouse model in which granulosa cell tumors occur with 100% penetrance in CF-1 mice that harbor a novel transgene encoding a chimeric LHbeta subunit. When this transgene is expressed in other strains of mice, including (C57BL/6 female symbol x CF-1 male symbol,Tg) F1 hybrids, luteomas develop even though levels of LH remain high. This dichotomous response permits a longitudinal comparison of global changes in transcriptomes uniquely associated with either granulosa cell tumors or luteomas. Herein we report numerous changes in the transcriptome, including a decrease in LH receptor mRNA and increases in several mRNAs that encode secreted proteins previously associated with granulosa cell tumors. Furthermore, we identified a constellation of mRNAs that encode proteins that may serve as new markers for this tumor phenotype. Additional experiments indicated that periodic treatment with human CG prevented formation of granulosa cell tumors in mice genetically predisposed to tumor development and, instead, led to the appearance of luteomas. More importantly, ovarian transcriptomes from the luteomas induced by ovulatory doses of human CG permitted refined confirmation of gene expression changes that were uniquely associated with either granulosa cell tumors in the permissive CF-1 genetic background or in luteomas in the F1 hybrids. Together, these dynamic changes in the ovarian transcriptome indict various signaling pathways potentially involved in mediating the actions of LH over time and, depending on genetic background, the formation of either a luteoma or a granulosa cell tumor.

WNT2B2 mRNA, up-regulated in primary gastric cancer, is a positive regulator of the WNT- beta-catenin-TCF signaling pathway

Genetic alterations of WNT signaling molecules lead to carcinogenesis through activation of the beta-catenin-TCF signaling pathway. We have previously cloned and characterized WNT2B/WNT13 gene on human chromosome 1p13, which is homologous to proto-oncogene WNT2 on human chromosome 7q31. WNT2B1 and WNT2B2 mRNAs, generated from the WNT2B gene due to alternative splicing of the alternative promoter type, encode almost identical polypeptides with divergence in the N-terminal region. WNT2B2 mRNA rather than WNT2B1 mRNA is preferentially expressed in NT2 cells with the potential of neuronal differentiation. Here, we describe our investigations of expression of WNT2B mRNAs in various types of human primary cancer. Matched tumor/normal expression array analysis revealed that WNT2B mRNAs were significantly up-regulated in 2 of 8 cases of primary gastric cancer. WNT2B2 mRNA rather than WNT2B1 mRNA was found to be preferentially up-regulated in a case of primary gastric cancer (signet ring cell carcinoma). Function of WNT2B1 mRNA and that of WNT2B2 mRNA were investigated by using Xenopus axis duplication assay. Injection of synthetic WNT2B1 mRNA into the ventral marginal zone of fertilized Xenopus eggs at the 4-cell stage did not induce axis duplication. In contrast, ventral injection of synthetic WNT2B2 mRNA induced axis duplication in 90% of embryos (complete axis duplication, 24%). These results strongly suggest that WNT2B2 up-regulation in some cases of gastric cancer might lead to carcinogenesis through activation of the beta-catenin-TCF signaling pathway.

Cytoplasmic/nuclear expression without mutation of exon 3 of the beta-catenin gene is frequent in the development of the neoplasm of the uterine cervix

OBJECTIVE

The dual function of beta-catenin (e.g., as an intermediate protein between adherence junctions and the microfilaments, and as a mediator of the Wnt signaling pathway) is currently known. Stabilization of beta-catenin and subsequent activation of the Wnt signaling pathway are involved in the development of some malignancies. We analyzed the immunohistochemical localization of beta-catenin and the somatic mutation of exon 3 of the beta-catenin gene in the malignant phenotype of the uterine cervix.

METHODS

Immunohistochemical localization of beta-catenin and mutation of exon 3 of the beta-catenin gene were analyzed in 38 precancerous lesions and 43 cancerous lesions.

RESULTS

In normal cervix, beta-catenin was observed around the plasma membrane of the cells in the basal and parabasal layers of the epithelium. The frequency of cytoplasmic/nuclear beta-catenin expression correlated with a high histological grade of cervical intraepithelial neoplasia. Among invasive carcinomas, 11 (73%) of 15 samples showed cytoplasmic/nuclear localization to variable extents. A mutational analysis showed that mutation occurred in 7 of 68 specimens. Six cases with mutations revealed cytoplasmic/nuclear beta-catenin expression, though 32 (84%) of the 38 samples showing cytoplasmic/nuclear beta-catenin expression were not associated with the mutation.

CONCLUSION

These results indicate that cytoplasmic/nuclear expression of beta-catenin is associated with the malignant phenotype of the cervix, but the contribution of mutation of the beta-catenin gene is limited.

Molecular cloning and characterization of WNT3A and WNT14 clustered in human chromosome 1q42 region

Human WNT3A and WNT14 cDNAs were cloned and characterized. WNT3A and WNT14 encoded WNT family protein of 352 and 365 amino acids, respectively. The 3.0-kb WNT3A mRNA was moderately expressed in placenta, and the 4.4-kb WNT14 mRNA was moderately expressed in skeletal muscle and heart. Although WNT3A mRNA was not detected in 35 human cancer cell lines, WNT14 mRNA was expressed in gastric cancer cell lines TMK1, MKN7, MKN45 and KATO-III. WNT3A and WNT14 genes, clustered in the head to head manner with an interval of about 58.0 kb, were mapped to human chromosome 1q42 region by fluorescence in situ hybridization. WNT3 and WNT15, clustered in human chromosome 17q21 region, are related genes of WNT3A and WNT14, respectively. WNT3A-WNT14 gene cluster and WNT3-WNT15 gene cluster might be generated due to duplication of ancestral gene cluster, just like WNT10A-WNT6 gene cluster and WNT10B-WNT1 gene cluster. Integration sites of mouse mammary tumor virus (MMTV) are located in the mouse chromosomal regions corresponding to these human WNT gene clusters. These results strongly suggest that unidentified nucleotide motif responsible for susceptibility to recombination might exist within the intergenic regions of these WNT gene clusters.

WNT10A and WNT6, clustered in human chromosome 2q35 region with head-to-tail manner, are strongly coexpressed in SW480 cells

Human WNT10A and WNT6 were cloned and characterized. WNT10A encoded a 417-amino-acid polypeptide with WNT core domain, and WNT6 encoded a 365-amino-acid polypeptide with N-terminal signal peptide, WNT core domain, and RGD motif. WNT10A and WNT6 genes were clustered in the head-to-tail manner with an interval less than 7.0 kb in human chromosome 2q35 region. Among human WNT family, WNT10A was most homologous to WNT10B (59.2% amino-acid identity), and WNT6 was most homologous to WNT1 (47.4% amino-acid identity). WNT10B and WNT1 genes were also clustered in human chromosome 12q13 region. Two WNT gene clusters in human chromosome 2q35 and 12q13 regions might be generated due to duplication of ancestral gene cluster. The 3.0- and 2.4-kb WNT10A mRNAs were expressed in fetal kidney, placenta, adult spleen and kidney. The 2.0-kb WNT6 mRNA was coexpressed with WNT10A in placenta and adult spleen. WNT10A and WNT6 were strongly coexpressed in SW480 (colorectal cancer). In addition to SW480, WNT10A was strongly expressed in HL-60 (promyelocytic leukemia) and Raji (Burkitt's lymphoma), and WNT6 in HeLa S3 (cervical cancer). Overexpression WNT10A and WNT6 might play key roles in human carcinogenesis through activation of WNT-beta-catenin-TCF signaling pathway, just like Wnt10b and Wnt1.

Wnt receptors and Wnt inhibitors are expressed in gradients in the developing telencephalon

The caudomedial margin of the medial pallium, known as the cortical hem, expresses several Wnt genes that have been shown to be crucial for cortical development. We examined the expression of members of the Frizzled (mFz) family of Wnt receptors and the Secreted Frizzled Related Protein (SFRP) family of Wnt inhibitors during telencephalic development. We found that mFz-5 and mFz-8 are specifically expressed in the neocortical neuroepithelium and excluded from the hippocampal neuroepithelium in early telencephalic development, whereas mFz-9 and mFz-10 have expression domains confined to the medial pallium. In addition, SFRP-1 and SFRP-3 are expressed in opposing anterolateral to caudomedial gradients within the telencephalic ventricular zone throughout corticogenesis.

FZD4S, a splicing variant of frizzled-4, encodes a soluble-type positive regulator of the WNT signaling pathway

Frizzled-1 (FZD1)-FZD10 are seven-transmembrane-type WNT receptors, and SFRP1-SFRP5 are soluble-type WNT antagonists. These molecules are encoded by mutually distinct genes. We have previously isolated and characterized the 7.7-kb FZD4 mRNA, encoding a seven-transmembrane receptor with the extracellular cysteine-rich domain (CRD). Here, we have cloned and characterized FZD4S, a splicing variant of the FZD4 gene. FZD4S, corresponding to the 10.0-kb FZD4 mRNA, consisted of exon 1, intron 1, and exon 2 of the FZD4 gene. FZD4S encoded a soluble-type polypeptide with the N-terminal part of CRD, and was expressed in human fetal kidney. Injection of synthetic FZD4S mRNA into the ventral marginal zone of Xenopus embryos at the 4-cell stage did not induce axis duplication by itself, but augmented the axis duplication potential of coinjected Xwnt-8 mRNA. These results indicate that the FZD4 gene gives rise to soluble-type FZD4S as well as seven-transmembrane-type FZD4 due to alternative splicing, and strongly suggest that FZD4S plays a role as a positive regulator of the WNT signaling pathway.

Molecular Cloning and Characterization of RNF26 on Human Chromosome 11q23 Region, Encoding a Novel RING Finger Protein with Leucine Zipper

Genetic alterations of RING finger genes, encoding an ubiquitin-protein ligase, are implicated in several types of human cancer through dysregulation of growth regulators. Here, a novel RING finger gene, RNF26, was cloned and characterized. The RNF26 gene on human chromosome 11q23 region was found to encode a polypeptide of 433 amino acids with the N-terminal leucine zipper domain and the C-terminal RING finger domain. Among the RING finger protein family, RING finger domains of RNF26, CGR19, NEURL, KIAA0554, and AK022937 were found to constitute a novel C3HC5 subfamily, which is distinct from C3H2C3 or C3HC4 subfamilies. RING finger domain of RNF26 was most homologous to that of CGR19 (49% amino-acid identity). The 3.2-kb RNF26 mRNA was expressed ubiquitously in normal human tissues, but was upregulated in several human cancer cell lines, including HL-60 (promyelocytic leukemia), HeLa S3 (cervical uterus cancer), SW480 (colorectal cancer), and MKN7 (gastric cancer). In addition, RNF26 was upregulated in 50% of primary gastric cancer examined in this study. Although substrates of ubiquitination mediated by RNF26 remain to be elucidated, RNF26 upregulation in several types of human cancer might be implicated in carcinogenesis through dysregulation of its substrates.

Molecular cloning and characterization of MFRP, a novel gene encoding a membrane-type Frizzled-related protein

The Frizzled-type cysteine-rich domain (CRD) is a binding motif for soluble-type glycoprotein WNTs, which play key roles in embryogenesis and carcinogenesis. Here, we have cloned and characterized a novel gene MFRP, encoding a type II transmembrane protein with CRD. In addition to CRD, two tandem-repeats containing the Cubilin domain approximately the MFRP domain were present in the extracellular region of MFRP. Although MFRP was homologous to Corin, FZDs, and SFRPs in CRD, amino-acid identities between CRD in MFRP and CRDs in these molecules were less than 40%. The MFRP gene on 11q23 consisted of at least 13 exons. The 4.0-kb MFRP was not detected by Northern blot analysis in normal tissues other than adult and fetal brain. The MFRP mRNA was undetectable in seven gastric cancer cell lines, seven brain tumor cell lines, and other eight tumor cell lines. Regional distribution of the MFRP mRNA in human brain was further investigated, and MFRP was found to be expressed strongly in medulla oblongata, and weakly in hippocampus and corpus callosum. Thus, MFRP with CRD might play key roles in medulla oblongata as a regulator of the WNT signaling pathway.