Antagonizing canonical Wnt signaling pathway by recombinant human sFRP4 purified from E. coli and its implications in cancer therapy

The Multifaceted Role of WNT Signaling in Alzheimer's Disease Onset and Age-Related Progression

The evolutionary conserved WNT signaling pathway orchestrates numerous complex biological processes during development and is critical to the maintenance of tissue integrity and homeostasis in the adult. As it relates to the central nervous system, WNT signaling plays several roles as it relates to neurogenesis, synaptic formation, memory, and learning. Thus, dysfunction of this pathway is associated with multiple diseases and disorders, including several neurodegenerative disorders. Alzheimer's disease (AD) is characterized by several pathologies, synaptic dysfunction, and cognitive decline. In this review, we will discuss the various epidemiological, clinical, and animal studies that demonstrate a precise link between aberrant WNT signaling and AD-associated pathologies. In turn, we will discuss the manner in which WNT signaling influences multiple molecular, biochemical, and cellular pathways upstream of these end-point pathologies. Finally, we will discuss how merging tools and technologies can be used to generate next generation cellular models to dissect the relationship between WNT signaling and AD.

Sfrp4 expression in thyroxine treated calvarial cells

AIMS

Evidence suggests alterations of thyroid hormone levels can disrupt normal bone development. Most data suggest the major targets of thyroid hormones to be the Htra1/Igf1 pathway. Recent discovery by our group suggests involvement of targets WNT pathway, specifically overexpression of antagonist Sfrp4 in the presence of exogenous thyroid hormone.

MAIN METHODS

Here we aimed to model these interactions in vitro using primary and isotype cell lines to determine if thyroid hormone drives increased Sfrp4 expression in cells relevant to craniofacial development. Transcriptional profiling, bioinformatics interrogation, protein and function analyses were used.

KEY FINDINGS

Affymetrix transcriptional profiling found Sfrp4 overexpression in primary cranial suture derived cells stimulated with thyroxine in vitro. Interrogation of the SFRP4 promoter identified multiple putative binding sites for thyroid hormone receptors. Experimentation with several cell lines demonstrated that thyroxine treatment induced Sfrp4 expression, demonstrating that Sfrp4 mRNA and protein levels are not tightly coupled. Transcriptional and protein analyses demonstrate thyroid hormone receptor binding to the proximal promoter of the target gene Sfrp4 in murine calvarial pre-osteoblasts. Functional analysis after thyroxine hormone stimulation for alkaline phosphatase activity shows that pre-osteoblasts increase alkaline phosphatase activity compared to other cell types, suggesting cell type susceptibility. Finally, we added recombinant SFRP4 to pre-osteoblasts in combination with thyroxine treatment and observed a significant decrease in alkaline phosphatase positivity.

SIGNIFICANCE

Taken together, these results suggest SFRP4 may be a key regulatory molecule that prevents thyroxine driven osteogenesis. These data corroborate clinical findings indicating a potential for SFRP4 as a diagnostic or therapeutic target for hyperostotic craniofacial disorders.

Emerging strategies for sensitization of therapy resistant tumors toward cancer therapeutics by targeting the Bcl-2 family, TGF-β, Wnt/β-Catenin, RASSF and miRNA regulated signaling pathways

Conventional chemotherapy relies on the cytotoxicity of chemo-drugs to inflict destructive effects on tumor cells. However, as most tumor cells develop resistance to chemo-drugs, small doses of chemo-drugs are unlikely to provide significant clinical benefits in cancer treatment while high doses of chemo-drugs have been shown to impact normal human cells negatively due to the non-specific nature and cytotoxicity associated with chemo-drugs. To overcome this challenge, sensitizations of tumor cells with bioactive molecules that specifically target the pro-survival and pro-apoptosis signaling pathways of the tumor cells are likely to increase the therapeutic impacts and improve the clinical outcomes by reducing the dependency and adverse effects associated with using high doses of chemo-drugs in cancer treatment. This review focuses on emerging strategies to enhance the sensitization of tumor cells toward cancer therapies based on our understanding of tumor cell biology and underlying signaling pathways.

lncRNAS56464.1 as a ceRNA promotes the proliferation of fibroblast‑like synoviocytes in experimental arthritis via the Wnt signaling pathway and sponges miR‑152‑3p

Rheumatoid arthritis (RA) is an autoimmune disease that occurs in approximately 1.0% of the general population. In RA patients, physical disability and joint damage are the major prognostic factors, which are associated with a reduction in the quality of life and early mortality. At present, the exact molecular mechanism of RA remains elusive. Long noncoding RNAs (lncRNAs) have been revealed to play a regulatory role in the pathogenesis of RA. To reveal the function of lncRNAs in rheumatoid arthritis, lncRNAS56464.1 was screened to verify its targeting of the microRNA (miR)-152-3p/Wnt pathway and its effect on the proliferation of fibroblast-like synoviocytes (FLS). In the present study, based on the competing endogenous RNA (ceRNA) theory, siRNA was designed for transfection into FLS to calculate the lncRNAS56464.1 interference efficiency and then the effect of lncRNAS56464.1 interference on FLS proliferation was detected by MTT assay. Then, lncRNAS56464.1 targeting of the miR-152-3p/Wnt pathway was detected by a dual-luciferase reporter assay. In addition, RT-qPCR, immunofluorescence and western blotting techniques were employed to detect the expression of lncRNAS56464.1, miR-152-3p and some key genes of the Wnt signaling pathway in FLS after lncRNAS56464.1 interference. The results revealed that lncRNAS56464.1 could combine with miR-152-3p and promoted the proliferation of FLS. In addition, lncRNAS56464.1 interference could not only decrease the proliferation of FLS and the expression of Wnt1, β-catenin, c-Myc, cyclin D1, and p-GSK-3β/GSK-3β, but it also increased the expression of SFRP4. The present data indicated that lncRNAS56464.1 could target the miR-152-3p/Wnt pathway to induce synovial cell proliferation and then participate in the pathogenesis of RA.

Negative regulators of Wnt signaling in non-small cell lung cancer: Theoretical basis and therapeutic potency

Significant advances in the treatment of non-small cell lung cancer (NSCLC) have been made over the past decade, and they predominantly involve molecular targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. However, despite the initial good response, drug resistance eventually develops. The Wnt signaling pathway has recently been considered important in embryonic development and tumorigenesis in many cancers, particularly NSCLC. Moreover, the aberrant Wnt pathway plays a significant role in NSCLC and is associated with cancer cell proliferation, metastasis, invasion and drug resistance, and the suppression of canonical or noncanonical Wnt signaling through various biological or pharmacological negative regulators has been proven to produce specific anticancer effects. Thus, blocking the Wnt pathway via its negative regulators may overcome the resistance of current treatment methods and lead to new treatment strategies for NSCLC. Therefore, in this review, we summarize recent studies on the role of negative regulators in Wnt signaling in NSCLC and the therapeutic potency of these molecules as agents and targets for NSCLC treatments.

Extracellular vesicle-dependent effect of RNA-binding protein IGF2BP1 on melanoma metastasis

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is a multifunctional RNA-binding protein with an oncofetal pattern of expression shown to be implicated in the development of a variety of malignancies. In this study, we explored the role and mechanisms of IGF2BP1 in melanoma development and progression. In two different in vivo models, we showed that while genetic deletion or shRNA-mediated suppression of IGF2BP1 did not affect primary tumor formation, it drastically suppressed lung metastasis. Here we demonstrated that extracellular vesicles (EVs) secreted by melanoma cells mediate the effects of IGF2BP1 on metastasis: EVs from the IGF2BP1 knockdown melanoma cells failed to promote metastasis whereas EVs isolated from IGF2BP1-overexpressed melanoma cells further accelerated EV-induced metastasis. Moreover, the EVs from IGF2BP1 knockdown melanoma cells inhibited fibronectin deposition and accumulation of CD45⁺ cells in the lungs compared to control EVs, thus blocking the pre-metastatic niche formation potential of EVs. IGF2BP1 knockdown did not affect size, number, or protein/RNA concentration of secreted EVs or their uptake by recipient cells in vitro or in vivo. However, RNA-sequencing and proteomics analysis of the EVs revealed differential expression in a number of mRNA, proteins and miRNAs. This suggested that IGF2BP1 is intimately involved in the regulation of the cargo of EVs, thereby affecting the pro-metastatic function of melanoma-derived EVs. To the best of our knowledge, this is the first study that demonstrates the role of RNA-binding protein IGF2BP1 in EV-mediated promotion of melanoma metastasis and may provide novel avenues for the development of metastatic inhibitors.

[Expression of secreted frizzled-related protein 4 in DNA mismatch repair-deficient and mismatch repair-proficient colorectal cancers]

OBJECTIVE

To investigate the expressions of secreted frizzled-related protein 4 (SFRP4) in stage Ⅱ DNA mismatch repair-deficient (dMMR) and mismatch repair- proficient (pMMR) colorectal cancers and explore their clinical significance.

METHODS

We collected fresh stage Ⅱ colon cancer tissues with different MMR status detected by immunohistochemistry (IHC). The differentially expressed mRNAs between dMMR and pMMR tumors were identified by Affymetrix Human oeLncRNA gene chip, and the expression of SFRP4 in these cancer tissues and in colorectal cancer cell lines were detected using Western blotting and real- time quantitative PCR. The apoptosis rates of HCT116 cells with and without siRNA- mediated transient SFRP4 knockdown were determined using flow cytometry. We further investigated the expression pattern of Ki-67 and its correlation with SFRP4 expression.

RESULTS

Compared with pMMR colon cancer tissues or cells, both dMMR colon cancer tissues (P=0.014) and cells (P=0.0079) showed significantly increased expression of SFRP4, which was in negative correlation with Ki-67 (P=0.041). In HCT116 cells, transient SFRP4 knockdown resulted in decreased cell apoptosis, including both early apoptosis (P=0.003) and late apoptosis (P=0.024).

CONCLUSIONS

Up-regulation of SFRP4 in dMMR stage Ⅱ colon cancer promotes apoptosis and inhibits proliferation of the cancer cells, and may improve the prognosis of dMMR colon cancer.

Suppression of tumor cell proliferation and migration by human umbilical cord mesenchymal stem cells: A possible role for apoptosis and Wnt signaling

Human umbilical cord-derived mesenchymal stem cells (hUCMSCs) represent potential therapeutic tools for solid tumors. However, there are numerous inconsistent results regarding the effects of hUCMSCs on tumors, and the mechanisms underlying this remain poorly understood. The present study further examined this controversial issue by analyzing the molecular mechanisms of the inhibitory effects of hUCMSCs on the proliferation and migration of the human lung cancer A549 cell line and the human hepatocellular carcinoma (HCC) BEL7402 cell line in vitro. Flow cytometric analysis demonstrated that hUCMSCs arrested tumor cells in specific phases of the cell cycle and induced the apoptosis of tumor cells by using the hUCMSC-conditioned medium (hUCMSC-CM). The hUCMSC-CM also attenuated the migratory abilities of the two tumor cell types. Furthermore, the expression of B-cell lymphoma 2 (Bcl-2), the pro-form of caspase-7 (pro-caspase-7), β-catenin and c-Myc was downregulated, while that of ephrin receptor (EphA5), a biomarker of cancer cell dormancy, was slightly increased in these two tumor cell lines treated with hUCMSC-CM. Specifically, when co-cultured via direct cell-to-cell contact, hUCMSCs were able to spontaneously fuse with any of the two types of solid tumor cells. These observations suggested that hUCMSCs may be a promising candidate for the biological therapy of lung cancer and HCC. Future studies should focus on detailed evidence for cell fusion, as well as other mechanisms proposed in the present study, by introducing additional experimental approaches and models.

Canonical WNT/β-Catenin Signaling Plays a Subordinate Role in Rhabdomyosarcomas

The development of skeletal muscle from immature precursors is partially driven by canonical WNT/β-catenin signaling. Rhabdomyosarcomas (RMS) are immature skeletal muscle-like, highly lethal cancers with a variably pronounced blockade of muscle differentiation. To investigate whether canonical β-catenin signaling in RMS is involved in differentiation and aggressiveness of RMS, we analyzed the effects of WNT3A and of a siRNA-mediated or pharmacologically induced β-catenin knock-down on proliferation, apoptosis and differentiation of embryonal and alveolar RMS cell lines. While the canonical WNT pathway was maintained in all cell lines as shown by WNT3A induced AXIN expression, more distal steps including transcriptional activation of its key target genes were consistently impaired. In addition, activation or inhibition of canonical WNT/β-catenin only moderately affected proliferation, apoptosis or myodifferentiation of the RMS tumor cells and a conditional knockout of β-catenin in RMS of Ptch ^del/+ mice did not alter RMS incidence or multiplicity. Together our data indicates a subordinary role of the canonical WNT/β-catenin signaling for RMS proliferation, apoptosis or differentiation and thus aggressiveness of this malignant childhood tumor.

Recombinant sFRP4 bound chitosan–alginate composite nanoparticles embedded with silver nanoclusters for Wnt/β-catenin targeting in cancer theranostics

Targeting a specific pathway aberrantly upregulated in cancer cells has shown immense potential in cancer therapy.