UNASSIGNED: Platinum-based chemotherapy regimens are a mainstay in the management of ovarian cancer (OC), but emergence of chemoresistance poses a significant clinical challenge. The persistence of ovarian cancer stem cells (OCSCs) at the end of primary treatment contributes to disease recurrence. Here, we hypothesized that the extracellular matrix protects CSCs during chemotherapy and supports their tumorigenic functions by activating integrin-linked kinase (ILK), a key enzyme in drug resistance.
UNASSIGNED: TCGA datasets and OC models were investigated using an integrated proteomic and gene expression analysis and examined ILK for correlations with chemoresistance pathways and clinical outcomes. Canonical Wnt pathway components, pro-survival signaling, and stemness were examined using OC models. To investigate the role of ILK in the OCSC-phenotype, a novel pharmacological inhibitor of ILK in combination with carboplatin was utilized in vitro and in vivo OC models.
UNASSIGNED: In response to increased fibronectin (FN) secretion and integrin β1 clustering, aberrant ILK activation supported the OCSC phenotype, contributing to OC spheroid proliferation and reduced response to platinum treatment. Complexes formed by ILK with the Wnt receptor frizzled 7 (Fzd7) were detected in tumors and showed a strong correlation with metastatic progression. Moreover, TCGA datasets confirmed that combined expression of ILK and Fzd7 in high grade serous ovarian tumors is correlated with reduced response to chemotherapy and poor patient outcomes. Mechanistically, interaction of ILK with Fzd7 increased the response to Wnt ligands, thereby amplifying the stemness-associated Wnt/β-catenin signaling. Notably, preclinical studies showed that the novel ILK inhibitor compound 22 (cpd-22) alone disrupted ILK interaction with Fzd7 and CSC proliferation as spheroids. Furthermore, when combined with carboplatin, this disruption led to sustained AKT inhibition, apoptotic damage in OCSCs and reduced tumorigenicity in mice.
UNASSIGNED: This \"outside-in\" signaling mechanism is potentially actionable, and combined targeting of ILK-Fzd7 may represent a new therapeutic strategy to eradicate OCSCs and improve patient outcomes.

Intestinal homeostasis depends on interactions between the intestinal epithelium, the immune system and the microbiota. Because of these complicated connections, there are many problems that need to be solved. Current research has indicated that genes targeted by Wnt signaling are responsible for controlling intestinal stem cell fate and for modulating intestinal homeostasis. Our data show that loss of frizzled 7 (Fzd7), an important element in Wnt signaling, interrupts the differentiation of mouse intestinal stem cells into absorptive progenitors instead of secretory progenitors (precursors of goblet and Paneth cells). The alteration in canonical Wnt and Notch signaling pathways interrupts epithelial homeostasis, resulting in a decrease in physical protection in the intestine. Several phenotypes in our Fzd7-deleted model were similar to the features of enterocolitis, such as shortened intestines, decreased numbers of goblet cells and Paneth cells, and severe inflammation. Additionally, loss of Fzd7 exacerbated the defects in a chemical-induced colitis model and could initiate tumorigenesis. These findings may provide important information for the discovery of efficient therapeutic methods to treat enterocolitis and related cancers in the intestines.

OBJECTIVE: Frizzled 7 (FZD7) is abnormally expressed and activated in a variety of cancers. In ovarian cancer, overexpression of FZD7 reduces the sensitivity of platinum-resistant ovarian cancer cells to ferroptosis, thereby allowing cancer cells to survive. However, whether FZD7 inhibits ferroptosis in ovarian cancer cells and its mechanisms are remain unclear. This study aims to explore the effects of FZD7 and its upstream regulator miR-1-3p on ferroptosis in ovarian cancer cells are evaluated to clarify the molecular mechanism for miR-1-3p and FZD7\'s involvement in ferroptosis in ovarian cancer cells.
METHODS: Human ovarian cancer cell lines HO8910 and SKOV3 were used as the research subjects. In the first part of the experiment, human ovarian cancer cells were transfected with blank plasmid and FZD7 overexpression plasmid, respectively; in the second and third parts, human ovarian cancer cells were transfected with miR-1-3p mimics negative control, miR-1-3p mimics, miR-1-3p inhibitors negative control, and miR-1-3p inhibitors, respectively; in the fourth part of the experiment, human ovarian cancer cells were transfected with miR-1-3p mimics and miR-1-3p mimics+FZD7 overexpression plasmid, respectively, and normal cultured cells were set as the control group. The human ovarian cancer cell ferroptosis model was established by incubating human ovarian cancer cells with different treatments with ferroptosis inducer Erastin or RSL3. Real-time RT-PCR was used to detect the mRNA expression levels of FZD7 and miR-1-3p; Western blotting was used to detect the protein expression levels of FZD7; CCK-8 assay was used to detect the cell viability; lipid peroxidation colorimetric assay kit was used to detect the level of intracellular MDA; and iron assay kit was used to detect the level of intracellular Fe2+. Dual-luciferase assay was used to detect the targeting relationship between miR-1-3p and FZD7.
RESULTS: Overexpression of FZD7 increased the cell viability of human ovarian cancer cell lines HO8910 or SKOV3 (P<0.05, P<0.01, or P<0.001) and decreased the intracellular MDA levels (P<0.01) in Erastin-treated or RSL3-treated ovarian cancer cells. FZD7 was a direct target of miR-1-3p, which inhibited the expression of FZD7 (P<0.01) by binding to the 3\'-untranslated region (3\'UTR) site of FZD7. MiR-1-3p mimics decreased the cell viability of human ovarian cancer cell lines HO8910 or SKOV3 (P<0.05, P<0.01, or P<0.001) and increased the intracellular MDA levels (P<0.01) in Erastin-treated or RSL3-treated ovarian cancer cells; while miR-1-3p inhibitors significantly increased the cell viability of human ovarian cancer cell lines HO8910 or SKOV3 (P<0.05, P<0.01, or P<0.001) and decreased the intracellular MDA levels (P<0.01) in Erastin-treated or RSL3-treated ovarian cancer cells. The effect of miR-1-3p mimics on enhancing the sensitivity of human ovarian cancer cells to Erastin-induced or RSL3-induced ferroptosis was abrogated by overexpression of FZD7(P<0.05 or P<0.01).
CONCLUSIONS: MiR-1-3p enhances the sensitivity of ovarian cancer cells to ferroptosis by targeting FZD7.
目的: 卷曲蛋白7(Frizzled 7，FZD7)在多种癌症中异常表达和激活。在卵巢癌中，FZD7的过表达可降低铂耐药性卵巢癌细胞对铁死亡的敏感性，从而使癌细胞存活，但FZD7是否抑制卵巢癌细胞铁死亡及其相关机制尚未被阐明。本研究通过探究FZD7及其上游调控因子miR-1-3p对卵巢癌细胞铁死亡的影响，旨在明确miR-1-3p及FZD7参与卵巢癌细胞铁死亡的分子机制。方法: 以人卵巢癌细胞系HO8910和SKOV3为研究对象，第1部分实验将空白质粒和FZD7过表达质粒分别转染人卵巢癌细胞；第2，3部分实验将miR-1-3p模拟物阴性对照、miR-1-3p模拟物、miR-1-3p抑制剂阴性对照和miR-1-3p抑制剂分别转染人卵巢癌细胞；第4部分实验将miR-1-3p模拟物、miR-1-3p模拟物+FZD7过表达质粒分别转染人卵巢癌细胞，另设正常培养的对照组。采用铁死亡诱导剂Erastin或RSL3分别孵育经不同处理后的人卵巢癌细胞构建人卵巢癌细胞铁死亡模型。使用real-time RT-PCR检测FZD7和miR-1-3p的mRNA表达水平，蛋白质印迹法检测FZD7的蛋白质表达水平，CCK-8实验检测细胞活力，脂质过氧化比色测定试剂盒检测细胞内MDA水平，铁检测试剂盒检测细胞内Fe2+水平，双荧光素酶实验检测miR-1-3p和FZD7的靶向关系。结果: FZD7的过表达提高经Erastin或RSL3处理的人卵巢癌细胞系HO8910或SKOV3细胞的活力(P<0.05、P<0.01或P<0.001)，并降低细胞内MDA的水平(P<0.01)。FZD7是miR-1-3p的直接靶点，miR-1-3p通过与FZD7的3\'非翻译区(3\'-untranslated region，3\'UTR)位点结合，抑制FZD7的表达(P<0.01)。MiR-1-3p模拟物降低经Erastin或RSL3处理的人卵巢癌细胞系HO8910或SKOV3细胞的活力(P<0.05、P<0.01或P<0.001)，提高细胞内MDA的水平(P<0.01)，而miR-1-3p抑制剂则显著提高经Erastin或RSL3处理的人卵巢癌细胞系HO8910或SKOV3细胞的活力(P<0.05、P<0.01或P<0.001)，降低细胞内MDA的水平(P<0.01)。MiR-1-3p模拟物增强人卵巢癌细胞对Erastin或RSL3诱导细胞铁死亡敏感性的作用可以被FZD7的过表达所取消(P<0.05或P<0.01)。结论: MiR-1-3p靶向FZD7增强卵巢癌细胞对铁死亡的敏感性。.

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial condition characterized from hypertriglyceridemia and hepatic fat accumulation, in the absence of alcohol intake. NAFLD starts as steatosis (NAFL), and the continued injury relative to the toxic fat induces inflammation, steatohepatitis (NASH), and HCC. One of the factors determining liver degeneration during the evolution of NAFLD is a modification of Wnt/Frizzled (FZD) signaling. In particular, an inhibition of Wnt signaling and an overexpression of a specific FZD receptor protein, namely, the FZD7, have been observed in NAFLD. Actually, the prognosis and the follow-up of NAFLD is not easy, and the liver biopsy is the gold standard for an accurate detection of liver fibrosis. In this study, the modulation of the FZD7 expression levels in plasma-derived exosomes of NAFLD-affected patients, before and after specific lifestyle interventions, were experimentally evaluated by Western blotting analysis. The experimental data were analyzed by an accurate statistical study that indicated, in the exosomes derived from plasma of NAFLD patients with moderate or severe steatosis, an average expression level of FZD7 that was significantly higher than healthy subjects at baseline; conversely, the values were normalized after 90 days of specific lifestyle interventions. The overall results suggested that the FZD7 delivered by exosomes represents a good candidate as a new and effective biomarker for diagnosis and prognosis of NAFLD.

Mesenchymal-like stemness is characterized by epithelial-mesenchymal transition (EMT). Breast cancer (BC) cell mesenchymal-like stemness is responsible for distal lung metastasis. Interrogation of databases showed that Fzd7 was closely associated with a panel of mesenchymal-related genes and a panel of stemness-related genes. Fzd7 knockdown in mesenchymal-like MDA-MB-231 and Hs578T cells reduced expression of Vimentin, Slug and Zeb1, induced an epithelial-like morphology, inhibited cell motility, impaired mammosphere formation and decreased Lgr5+ subpopulation. In contrast, Fzd7 overexpression in MCF7 cells resulted in opposite changes. Fzd7 knockdown delayed xenograft tumor formation, suppressed tumor growth, and impaired lung metastasis. Mechanistically, Fzd7 combined with Wnt5a/b and modulated expression of phosphorylated Stat3 (p-STAT3), Smad3 and Yes-associated protein 1 (Yap1). Moreover, Fzd7-Wnt5b modulated expression of collagen, type VI, alpha 1 (Col6a1). Both Wnt5b knockdown and Col6a1 knockdown disrupted BC cell mesenchymal phenotype and stemness. Taken together, Fzd7 contributes to BC cell EMT and stemness, inducing tumorigenesis and metastasis, mainly through a non-canonical Wnt5b pathway. Col6a1 is implicated in Fzd7-Wnt5b signaling, and mediates Fzd7-Wnt5b -induced mesenchymal-like stemness. Video Abstract.

Retinopathies remain major causes of visual impairment in diabetic patients and premature infants. Introduction of anti-angiogenic drugs targeting vascular endothelial growth factor (VEGF) has transformed therapy for these proliferative retinopathies. However, limitations associated with anti-VEGF medications require to unravel new pathways of vessel growth to identify potential drug targets. Here, we investigated the role of Wnt/Frizzled-7 (Fzd7) pathway in a mouse model of oxygen-induced retinopathy (OIR). Using transgenic mice, which enabled endothelium-specific and time-specific Fzd7 deletion, we demonstrated that Fzd7 controls both vaso-obliteration and neovascular phases (NV). Deletion of Fzd7 at P12, after the ischemic phase of OIR, prevented formation of aberrant neovessels into the vitreous by suppressing proliferation of endothelial cells (EC) in tufts. Next we validated in vitro two Frd7 blocking strategies: a monoclonal antibody (mAbFzd7) against Fzd7 and a soluble Fzd7 receptor (CRD). In vivo a single intravitreal microinjection of mAbFzd7 or CRD significantly attenuated retinal neovascularization (NV) in mice with OIR. Molecular analysis revealed that Fzd7 may act through the activation of Wnt/β-catenin and Jagged1 expression to control EC proliferation in extra-retinal neovessels. We identified Fzd7/β-catenin signaling as new regulator of pathological retinal NV. Fzd7 appears to be a potent pharmacological target to prevent or treat aberrant angiogenesis of ischemic retinopathies.

Wnts are secreted signaling molecules that are implicated in a variety of growth-related processes. Frizzled proteins have been identified as receptors for Wnt ligands in vertebrates and invertebrates, but a functional role for dioecious flatworm Frizzleds has not been determined. To evaluate the endogenous role of Frizzled proteins during development, we have identified and characterized a Schistosoma japonicum frizzled gene (Sjfz7). We found that Sjfz7 encodes a 698 amino acid protein with typical characteristics of Frizzled proteins. The immunohistochemical localization pattern showed that Sjfz7 protein was extensively distributed in almost all tissues of S. japonicum, including subtegumental muscle cells, parenchymal cells, intestinal epithelial cells and male and female germ cells. This indicated that Sjfz7-mediated Wnt signaling might be associated with the development of musculature, intestinal tract and reproductive organs in schistosome. Comparing mRNA levels between frizzled family members showed that Sjfz7 mRNA was consistently higher in the developmental stages analyzed, suggesting that Sjfz7 may be responsible for more functional tasks than other frizzled family members. Comparing frizzled mRNA levels between not fully developed and normal worms suggested that Wnt signaling might be abnormal in not fully developed worms.

BACKGROUND: FZD7 has a critical role as a surface receptor of Wnt/β-catenin signaling in cancer cells. Suppressing Wnt signaling through blocking FZD7 is shown to decrease cell viability, metastasis and invasion. Bioinformatic methods have been a powerful tool in epitope designing studies. Small size, high affinity and human origin of scFv antibodies have provided unique advantages for these recombinant antibodies.
METHODS: Two epitopes from extracellular domain of FZD7 were designed using bioinformatic methods. Specific anti-FZD7 scFvs were selected against these epitopes through panning process. The specificity of the scFvs was assessed by phage ELISA and the ability to bind to FZD7 expressing cell line (MDA-MB-231) was determined by flowcytometry. Antiproliferative and apoptotic effects of the scFvs were evaluated by MTT and Annexin V/PI assays. The effects of selected scFvs on expression level of Surivin, c-Myc and Dvl genes were also evaluated by real-time PCR.
RESULTS: Results demonstrated selection of two specific scFvs (scFv-I and scFv-II) with frequencies of 35 and 20%. Both antibodies bound to the corresponding peptides and cell surface receptors as shown by phage ELISA and flowcytometry, respectively. The scFvs inhibited cell growth of MDA-MB-231 cells significantly as compared to untreated cells. Growth inhibition of 58.6 and 53.1% were detected for scFv-I and scFv-II, respectively. No significant growth inhibition was detected for SKBR-3 negative control cells. The scFvs induced apoptotic effects in the MDA-MB-231 treated cells after 48 h, which were 81.6 and 74.9% for scFv-I and scFv-II, respectively. Downregulation of Surivin, c-Myc and Dvl genes were also shown after 48h treatment of cells with either of scFvs (59.3-93.8%). ScFv-I showed significant higher antiproliferative and apoptotic effects than scFv-II.
CONCLUSIONS: Bioinformatic methods could effectively select potential epitopes of FZD7 protein and suggest that epitope designing by bioinformatic methods could contribute to the selection of key antigens for cancer immunotherapy. The selected scFvs, especially scFv-I, with high antiproliferative and apoptotic effects could be considered as effective agents for immunotherapy of cancers expressing FZD7 receptor including triple negative breast cancer.