Epigenetic alterations of the Wnt signaling pathway in cancer: a mini review

PIWI-interacting RNAs (PiRNAs) as emerging biomarkers and therapeutic targets in biliary tract cancers: A comprehensive review

Cancers affecting the biliary tract, such as gallbladder cancer and cholangiocarcinoma, make up a small percentage of adult gastrointestinal malignancies, but their incidence is on the rise. Due to the lack of dependable molecular biomarkers for diagnosis and prognosis, these cancers are often not detected until later stages and have limited treatment options. Piwi-interacting RNAs (piRNAs) are a type of small noncoding RNA that interacts with Piwi proteins and has been linked to various diseases, especially cancer. Manipulation of piRNA expression has the potential to serve as an important biomarker and target for therapy. This review uncovers the relationship between PIWI-interacting RNA (piRNA) and a variety of gastrointestinal cancers, including biliary tract cancer (BTC). It is evident that piRNAs have the ability to impact gene expression and regulate key genes and pathways related to the advancement of digestive cancers. Abnormal expression of piRNAs plays a significant role in the development and progression of digestive-related malignancies. The potential of piRNAs as potential biomarkers for diagnosis and prognosis, as well as therapeutic targets in BTC, is noteworthy. Nevertheless, there are obstacles and limitations that require further exploration to fully comprehend piRNAs' role in BTC and to devise effective diagnostic and therapeutic approaches using piRNAs. In summary, this review underscores the value of piRNAs as valuable biomarkers and promising targets for treating BTC, as we delve into the association between piRNAs and various gastrointestinal cancers, including BTC, and how piRNAs can impact gene expression and control essential pathways for digestive cancer advancement. The present research consists of a thorough evaluation presented in a storytelling style. The databases utilized to locate original sources were PubMed, MEDLINE, and Google Scholar, and the search was conducted using the designated keywords.

The Cross-Talk between Epigenetic Gene Regulation and Signaling Pathways Regulates Cancer Pathogenesis

Cancer begins due to uncontrolled cell division. Cancer cells are insensitive to the signals that control normal cell proliferation. This uncontrolled cell division is due to the accumulation of abnormalities in different factors associated with the cell division, including different cyclins, cell cycle checkpoint inhibitors, and cellular signaling. Cellular signaling pathways are aberrantly activated in cancer mainly due to epigenetic regulation and post-translational regulation. In this chapter, the role of epigenetic regulation in aberrant activation of PI3K/AKT, Ras, Wnt, Hedgehog, Notch, JAK/STAT, and mTOR signaling pathways in cancer progression is discussed. The role of epigenetic regulators in controlling the upstream regulatory proteins and downstream effector proteins responsible for abnormal cellular signaling-mediated cancer progression is covered in this chapter. Similarly, the role of signaling pathways in controlling epigenetic gene regulation-mediated cancer progression is also discussed. We have tried to ascertain the current status of potential epigenetic drugs targeting several epigenetic regulators to prevent different cancers.

MiR-873-5p: A Potential Molecular Marker for Cancer Diagnosis and Prognosis

miR-873 is a microRNA located on chromosome 9p21.1. miR-873-5p and miR-873-3p are the two main members of the miR-873 family. Most studies focus on miR-873-5p, and there are a few studies on miR-873-3p. The expression level of miR-873-5p was down-regulated in 14 cancers and up-regulated in 4 cancers. miR-873-5p has many targeted genes, which have unique molecular functions such as catalytic activity, transcription regulation, and binding. miR-873-5p affects cancer development through the PIK3/AKT/mTOR, Wnt/β-Catenin, NF-κβ, and MEK/ERK signaling pathways. In addition, the target genes of miR-873-5p are closely related to the proliferation, apoptosis, migration, invasion, cell cycle, cell stemness, and glycolysis of cancer cells. The target genes of miR-873-5p are also related to the efficacy of several anti-cancer drugs. Currently, in cancer, the expression of miR-873-5p is regulated by a variety of epigenetic factors. This review summarizes the role and mechanism of miR-873-5p in human tumors shows the potential value of miR-873-5p as a molecular marker for cancer diagnosis and prognosis.

CircCDYL Acts as a Tumor Suppressor in Wilms' Tumor by Targeting miR-145-5p

Circular RNAs (circRNA) have been reported to exert evident functions in many human carcinomas. However, the possible mechanisms concerning the circRNA in various tumors are still elusive. In this research, we analyzed the expression profile and biological functions of circular RNA CDYL (circCDYL, circBase ID: hsa_circ_0008285) in Wilms' tumor. Here, miRNA and gene expression were examined by real-time PCR in Wilms' tumor tissues and cell lines. The functions of circCDYL and its potential targets to influence cell proliferation, migration, and invasion in Wilms' tumor cells were determined by biological functional experiments in vitro and in vivo. We predicted and analyzed potential miRNA targets through online bioinformatic tools. To validate the interactions between circCDYL and its targets, we performed RNA fluorescence in situ hybridization, biotin-coupled miRNA capture assay, and biotin-coupled probe pull-down assay. Tight junction protein l (TJP1) was proved to be the target gene of the predicted miRNA by dual-luciferase reporter assay. The expression level of TJP1 in Wilms' tumor cells was identified via Western blot. We showed that circCDYL was downregulated in WT tissue compared with adjacent non-tumor tissue. Upregulation of circCDYL could reduce cell proliferation, migration, and invasion. Mechanically, circCDYL, functioning as a miRNA sponge, decreased the expression level of miR-145-5p and TJP1 3'UTR was validated as the target of miR-145-5p, facilitating the circCDYL/miR-145-5p/TJP1 axis. In conclusion, our study suggested circCDYL as a novel biomarker and therapeutic target for WT treatment.

Regulation of cancer stem cells in triple negative breast cancer

Triple Negative Breast Cancer (TNBC) is the most lethal subtype of breast cancer. Despite the successes of emerging targeted therapies, relapse, recurrence, and therapy failure rates in TNBC significantly outpace other subtypes of breast cancer. Mounting evidence suggests accumulation of therapy resistant Cancer Stem Cell (CSC) populations within TNBCs contributes to poor clinical outcomes. These CSCs are enriched in TNBC compared to non-TNBC breast cancers. The mechanisms underlying CSC accumulation have been well-characterized and discussed in other reviews. In this review, we focus on TNBC-specific mechanisms that allow the expansion and activity of self-renewing CSCs. We highlight cellular signaling pathways and transcription factors, specifically enriched in TNBC over non-TNBC breast cancer, contributing to stemness. We also analyze publicly available single-cell RNA-seq data from basal breast cancer tumors to highlight the potential of emerging bioinformatic approaches in identifying novel drivers of stemness in TNBC and other cancers.

Wnt/β-catenin Antagonists: Exploring New Avenues to Trigger Old Drugs in Alleviating Glioblastoma Multiforme

BACKGROUND

Glioblastoma multiforme is one of the most heterogenous primary brain tumor with high mortality. Nevertheless, of the current therapeutic approaches, survival rate remains poor with 12 to 15 months following preliminary diagnosis, this warrants the need for effective treatment modality. Wnt/β-catenin pathway is presumably the most noteworthy pathway up-regulated in almost 80% GBM cases contributing to tumor-initiation, progression and survival. Therefore, therapeutic strategies targeting key components of Wnt/β-catenin cascade using established genotoxic agents like temozolomide and pharmacological inhibitors would be an effective approach to modulate Wnt/β-catenin pathway. Recently, drug repurposing by means of effective combination therapy has gained importance in various solid tumors including GBM, by targeting two or more proteins in a single pathway, thereby possessing the ability to overcome the hurdle implicated by chemo-resistance in GBM.

OBJECTIVE

In this context, by employing computational tools, an attempt has been carried out to speculate the novel combinations against Wnt/β-catenin signaling pathway.

METHODS

We have explored the binding interactions of three conventional drugs namely temozolomide, metformin, chloroquine along with three natural compounds viz., epigallocatechin gallate, naringenin and phloroglucinol on the major receptors of Wnt/β-catenin signaling.

RESULTS

It was noted that all the experimental compounds possessed profound interaction with the two major receptors of Wnt/β-catenin pathway.

CONCLUSION

To the best of our knowledge, this study is the first of its kind to characterize the combined interactions of the afore-mentioned drugs on Wnt/β-catenin signaling in silico and this will putatively open up new avenues for combination therapies in GBM treatment.

Identification of Predictive Biomarkers of Response to HSP90 Inhibitors in Lung Adenocarcinoma

Heat shock protein 90 (HSP90) plays an essential role in lung adenocarcinoma, acting as a key chaperone involved in the correct functioning of numerous highly relevant protein drivers of this disease. To this end, HSP90 inhibitors have emerged as promising therapeutic strategies, even though responses to them have been limited to date. Given the need to maximize treatment efficacy, the objective of this study was to use isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic techniques to identify proteins in human lung adenocarcinoma cell lines whose basal abundances were correlated with response to HSP90 inhibitors (geldanamycin and radicicol derivatives). From the protein profiles identified according to response, the relationship between lactate dehydrogenase B (LDHB) and DNA topoisomerase 1 (TOP1) with respect to sensitivity and resistance, respectively, to geldanamycin derivatives is noteworthy. Likewise, rhotekin (RTKN) and decaprenyl diphosphate synthase subunit 2 (PDSS2) were correlated with sensitivity and resistance to radicicol derivatives. We also identified a relationship between resistance to HSP90 inhibition and the p53 pathway by glucose deprivation. In contrast, arginine biosynthesis was correlated with sensitivity to HSP90 inhibitors. Further study of these outcomes could enable the development of strategies to improve the clinical efficacy of HSP90 inhibition in patients with lung adenocarcinoma.

The nuclear transporter importin-11 regulates the Wnt/β-catenin pathway and acts as a tumor promoter in glioma

Karyopherins mediate the macromolecular transport between the cytoplasm and the nucleus and participate in cancer progression. However, the role and mechanism of importin-11 (IPO11), a member of the karyopherin family, in glioma progression remain undefined. Effects of IPO11 on glioma progression were detected using CCK-8, colony formation assay, flow cytometry analysis, caspase-3 activity assay, and Transwell invasion assay. Western blot analysis was used to detect the expression of active caspase-3, active caspase-7, active caspase-9, N-cadherin, Vimentin, E-cadherin, β-catenin, and c-Myc. The activity of Wnt/β-catenin pathway was evaluated by the T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factor reporter assay. Results showed that IPO11 knockdown inhibited proliferation and reduced colony number in glioma cells. IPO11 silencing promoted the apoptotic rate, increased expression levels of active caspase-3, caspase-7, and caspase-9, and enhanced caspase-3 activity. Moreover, IPO11 silencing inhibited glioma cell invasion by suppressing epithelial-to-mesenchymal transition (EMT). Mechanistically, IPO11 knockdown inactivated the Wnt/β-catenin pathway. β-Catenin overexpression abolished the effects of IPO11 silencing on the proliferation, apoptosis, and invasion in glioma cells. Furthermore, IPO11 silencing blocked the malignant phenotypes and repressed the Wnt/β-catenin pathway in vivo. In conclusion, IPO11 knockdown suppressed the malignant phenotypes of glioma cells by inactivating the Wnt/β-catenin pathway.

Circ_0007142/miR-186/FOXK1 axis promoted lung adenocarcinoma progression

Circular RNAs (circRNAs) are a class of non-coding RNAs could affect expression of specific genes which may induce tumor occurrence and progression. In this study, we identified 32 differentially expressed circRNAs between five pairs of lung adenocarcinoma and paracancerous tissues using circRNA microarray. And circ_0007142 expression was the most upregulated in five lung adenocarcinoma tissues. Meanwhile, circ_0007142 expression was remarkably over-expressed in lung adenocarcinoma tissues and cells. In addition, knockdown of circ_0007142 inhibited proliferation, migration, invasion and induced apoptosis of lung adenocarcinoma cells. Furthermore, knockdown of circ_0007142 inhibited the biological behavior of lung adenocarcinoma through miR-186/FOXK1 axis and inactivated the Wnt/β-catenin signaling pathway. Altogether, our study suggests Circ_0007142/miR-186/FOXK1 axis may play as an important role in progression of lung adenocarcinoma, which provided a novel potential mechanism about this disease.

Dnmt3b ablation impairs fracture repair through upregulation of Notch pathway

We previously established that DNA methyltransferase 3b (Dnmt3b) is the sole Dnmt responsive to fracture repair and that Dnmt3b expression is induced in progenitor cells during fracture repair. In the current study, we confirmed that Dnmt3b ablation in mesenchymal progenitor cells (MPCs) resulted in impaired endochondral ossification, delayed fracture repair, and reduced mechanical strength of the newly formed bone in Prx1-Cre;Dnmt3bf/f (Dnmt3bPrx1) mice. Mechanistically, deletion of Dnmt3b in MPCs led to reduced chondrogenic and osteogenic differentiation in vitro. We further identified Rbpjκ as a downstream target of Dnmt3b in MPCs. In fact, we located 2 Dnmt3b binding sites in the murine proximal Rbpjκ promoter and gene body and confirmed Dnmt3b interaction with the 2 binding sites by ChIP assays. Luciferase assays showed functional utilization of the Dnmt3b binding sites in murine C3H10T1/2 cells. Importantly, we showed that the MPC differentiation defect observed in Dnmt3b deficiency cells was due to the upregulation of Rbpjκ, evident by restored MPC differentiation upon Rbpjκ inhibition. Consistent with in vitro findings, Rbpjκ blockage via dual antiplatelet therapy reversed the differentiation defect and accelerated fracture repair in Dnmt3bPrx1 mice. Collectively, our data suggest that Dnmt3b suppresses Notch signaling during MPC differentiation and is necessary for normal fracture repair.

Dishevelled family proteins in serous ovarian carcinomas: a clinicopathologic and molecular study

Dishevelled family proteins (DVL1, DVL2, and DVL3) are cytoplasmic mediators involved in canonical and non-canonical Wnt signaling that are important for embryonic development. Since Wnt signaling promotes cell proliferation and invasion, its increased activation is associated with cancer development as well. To get deeper insight into the behavior of Dishevelled proteins in cancer, we studied their expression in serous ovarian carcinomas [both low- (LGSC) and high-grade (HGSC)], and HGSC cell lines OVCAR5, OVCAR8, and OVSAHO. DVL protein expression in serous ovarian carcinomas tissues was analyzed using immunohistochemistry, while DVL protein and mRNA expressions in HGSC cell lines were analyzed using Western blot and quantitative real-time PCR. DVL1 protein expression was significantly higher in LGSC compared with normal ovarian tissue, while DVL3 was overexpressed in both LGSC and HGSC. DVL2 and DVL3 protein expression was higher in HGSC cell lines when compared with normal control cell line FNE1, while DVL1, DVL2, and DVL3 mRNA expression was significantly increased only in OVSAHO cell line. Survival analysis revealed no significant impact of DVL proteins on patients' outcome. Our data show an active involvement of Dishevelled family proteins in serous ovarian carcinomas. Further studies should confirm the clinical relevance of these observations.

PD-L1 status in breast cancer: Current view and perspectives

Breast cancer was traditionally not considered a particularly immunogenic tumor. However, recent developments have shown that some aggressive triple-negative breast cancers are immunogenic, exhibit a resistance to chemotherapy and have a poor prognosis. These cancers have been shown to express molecules identified as targets for immunotherapy. Despite the advances, the challenges are many, and include identifying the patients that may benefit from immunotherapy. The best methods to analyze these samples and to evaluate immunogenicity are also major challenges. Therefore, the most accurate and reliable assessment of immune cells as potential targets is one of the most important aims in the current research in breast immunotherapy. In the present review, we briefly discuss the mechanisms of the regulation of checkpoint inhibitors (PD-1/PD-L1) in breast cancer and explore the predictive aspects in the PD-L1 testing.

Circular RNA hsa_circ_0007059 restrains proliferation and epithelial-mesenchymal transition in lung cancer cells via inhibiting microRNA-378

As newly discovered non-coding RNA (ncRNA), circular RNA (circRNA) has become a research hotspot in manifold cancers. But, the influences of hsa_circ_0007059 in lung cancer remain obscure. Expression of hsa_circ_0007059 in lung cancer tissues was firstly determined through RT-qPCR. After overexpressing hsa_circ_0007059, cell viability, apoptosis, p53/CyclinD1, Bax and Pro/Cleaved-Caspase-3 and EMT-correlative factors (E-cadherin, Vimetin, Twist1 and Zeb1) were tested in A549 and H1975 cells. MiR-378 expression in lung cancer tissues and cells was evaluated after miR-378 mimic transfection. Wnt/β-catenin and ERK1/2 pathways were finally evaluated in A549 and H1975 cells. Inhibition of hsa_circ_0007059 was discovered in lung cancer tissues. Overexpressed hsa_circ_0007059 evidently restrained cell proliferation, elevated p53 and repressed CyclinD1 expression, meanwhile triggered apoptosis and enhanced Bax and Cleaved-Caspase-3 expression. Increased hsa_circ_0007059 abated EMT via enhancement of E-cadherin and inhibition of Vimentin, Twist and Zeb1 in A549 and H1975 cells. MiR-378 was up-regulated in lung cancer tissues, declined by hsa_circ_0007059 overexpression in A549 and H1975 cells. Overexpressed hsa_circ_0007059 hindered Wnt/β-catenin and ERK1/2 pathways via suppressing miR-378 in A549 and H1975 cells. The investigations manifested that hsa_circ_0007059 abated cell proliferation and EMT process in lung cancer cells via inactivation of Wnt/β-catenin and ERK1/2 pathways via suppressing miR-378.

Molecular mechanisms underlying the antimetastatic activity of bufalin

Bufalin is a monomer compound extract from Chansu, which is a traditional Chinese medicine obtained from the skin and parotid venom glands of toads, such as Bufo bufo gargarizans Cantor and Bufo melanostictus Schneider. Chansu had been used in traditional Chinese medicine for >1,000 years due to its cardiac, anti-inflammatory and anticancer properties. Previous studies identified bufalin as the main anticancer compound of Chansu, and recent evidence has corroborated its anticancer properties. Bufalin inhibits cancer cell proliferation, induces cell cycle arrest, induces cancer cell apoptosis, inhibits neovascularization, induces cell differentiation, inhibits cancer metastasis and invasion, and enhances chemotherapeutic drug sensitivity. However, the function and mechanism of bufalin in metastatic cancer cells have not yet been expounded. The aim of the present review was to discuss the recent progress and prospects of bufalin in the prevention of cancer metastasis, particularly in inhibiting epithelial-to-mesenchymal transition.

Bufalin inhibits gastric cancer invasion and metastasis by down-regulating Wnt/ASCL2 expression

Achaete-scute-like 2 (ASCL2) is a transcription factor containing a basic helix-loop-helix (bHLH) domain and is a downstream target of Wnt signaling in intestinal stem cells. Bufalin is the primary active ingredient in Chan Su, a traditional Chinese medicine obtained from the skin and parotid venom glands of toads. The purpose of this study was to research the anti-invasion and anti-metastasis activity of bufalin in gastric cancer and to identify the potential mechanism. Bufalin inhibited gastric cancer cell invasion and metastasis, suppressed cancer cell colony formation, and inhibited the growth of subcutaneous xenografted tumors in nude mice. Furthermore, bufalin inhibited ASCL2 expression and down-regulated the expression of invasion-related genes such as MMP2, MMP9, and vimentin, thereby suppressing epithelial-mesenchymal transition (EMT) in gastric cancer. A Wnt signaling inhibitor (XAV939) down-regulated invasion and the expression of ASCL2, β-catenin, and vimentin but up-regulated E-cadherin expression. In nude mice, bufalin inhibited the tumorigenic behavior of gastric cancer cells, induced cancer cell apoptosis, and regulated invasion-related gene expression. Together, our results suggest that bufalin arrests invasion and metastasis and that its mechanism of action may involve down-regulating Wnt/ASCL2 expression.

Wnt Signalling-Targeted Therapy in the CMS2 Tumour Subtype: A New Paradigm in CRC Treatment?

Colorectal cancers (CRC) belonging to the consensus molecular subtype 2 (CMS2) have the highest incidence rate, affect mainly the distal colon and rectum, and are characterized by marked Wnt/β-catenin/Transcription Factor 7-Like 2 (TCF7L2) pathway activation and also by activation of epidermal growth factor receptor (EGFR) signalling. Despite having the highest overall survival, CMS2 tumours are often diagnosed at stage III when an adjuvant chemotherapy-based regimen is recommended. Nevertheless, colorectal cancer stem cells (CSCs) and circulating tumour cells may still evade the current therapeutic options and metastasize, stressing the need to develop more tailored therapeutic strategies. For example, activation of EGFR signalling is being used as a target for tailored therapy, however, therapy resistance is frequently observed. Therefore, targeting the Wnt signalling axis represents an additional therapeutic strategy, considering that CMS2 tumours are "Wnt-addicted". Several efforts have been made to identify Wnt antagonists, either of synthetic or natural origin. However, an inverse gradient of Wnt/β-catenin/TCF7L2 signalling activity during CRC progression has been suggested, with early stage and metastatic tumours displaying high and low Wnt signalling activities, respectively, which lead us to revisit the "just-right" signalling model. This may pinpoint the use of Wnt signalling agonists instead of antagonists for treatment of metastatic stages, in a context-dependent fashion. Moreover, the poor immunogenicity of these tumours challenges the use of recently emerged immunotherapies. This chapter makes a journey about CMS2 tumour characterization, their conventional treatment, and how modulation of Wnt signalling or immune response may be applied to CRC therapy. It describes the newest findings in this field and indicates where more research is required.

Cancer metastasis - tricks of the trade

Decades of cancer research have unraveled genetic, epigenetic and molecular pathways leading to plausible therapeutic targets; many of which hold great promise in improving clinical outcomes. Metastatic tumors become evident early on and are one of the major causes of cancer-related fatalities worldwide. This review depicts the sequential events of cancer metastasis. Genetic and epigenetic heterogeneity influences local tumor cell invasion, intravasation, survival in circulation, extravasation and colonization to distant sites. Each sequential event is associated with heterogeneous tumor microenvironment, gain of competence, unique population of cancer stem cells (CSCs), circulatory pathway, compatible niche and immune system support. A tight regulation of metastasis-promoting mechanisms and, in parallel, evading inhibitory mechanisms contribute to the severity and site of metastasis. A comprehensive understanding of tumor cell fate as an individual entity, as well as in combination with different promoting factors and associated molecular mechanisms, is anticipated in the coming years. This will enable scientists to depict design strategies for targeted cancer therapies.

CBX7 negatively regulates migration and invasion in glioma via Wnt/β-catenin pathway inactivation

CBX7, a member of the Polycomb-group proteins, plays a significant role in normal and cancerous tissues and has been defined as a tumor suppressor in thyroid, breast and pancreatic cancers. However, its function in glioma remains undefined. CBX7 expression is decreased in glioma, especially in higher grade cases, according to data in the CGGA, GSE16001 and TCGA databases. Further experimental evidence has shown that exogenous CBX7 overexpression induced apoptosis and inhibited cell proliferation, colony formation and migration of glioma cells. In this study, we show that the invasive ability of glioma cells was decreased following CBX7 overexpression and CBX7 overexpression was associated with Wnt/β-catenin pathway inhibition, which also decreased downstream expression of ZEB1, a core epithelial-to-mesenchymal transition factor. This reduction in Wnt signaling is controlled by DKK1, a specific Wnt/β-catenin inhibitor. CBX7 enhances DKK1 expression by binding the DKK1 promoter, as shown in Luciferase reporter assays. Our data confirm that CBX7 inhibits EMT and invasion in glioma, which is manifested by influencing the expression of MMP2, MMP9, E-cadherin, N-cadherin and Vimentin in LN229, T98G cells and primary glioma cells (PGC). Furthermore, as a tumor suppressor, CBX7 expression is pivotal to reduce tumor invasion and evaluate prognosis.

CircRNA: functions and properties of a novel potential biomarker for cancer

Circular RNAs, a novel class of endogenous noncoding RNAs, are characterized by their covalently closed loop structures without a 5′ cap or a 3′ Poly A tail. Although the mechanisms of circular RNAs’ generation and function are not fully clear, recent research has shown that circular RNAs may function as potential molecular markers for disease diagnosis and treatment and play an important role in the initiation and progression of human diseases, especially in tumours. This review summarizes some information about categories, biogenesis, functions at the molecular level, properties of circular RNAs and the possibility of circular RNAs as biomarkers in cancers.

Circular RNA-ITCH Suppresses Lung Cancer Proliferation via Inhibiting the Wnt/β-Catenin Pathway

As a special form of noncoding RNAs, circular RNAs (circRNAs) played important roles in regulating cancer progression mainly by functioning as miRNA sponge. While the function of circular RNA-ITCH (cir-ITCH) in lung cancer is still less reported, in this study, we firstly detected the expression of cir-ITCH in tumor tissues and paired adjacent noncancer tissues of 78 patients with lung cancer using a TaqMan-based quantitative real-time PCR (qRT-PCR). The results showed that the expression of cir-ITCH was significantly decreased in lung cancer tissues. In cellular studies, cir-ITCH was also enhanced in different lung cancer cell lines, A549 and NIC-H460. Ectopic expression of cir-ITCH markedly elevated its parental cancer-suppressive gene, ITCH, expression and inhibited proliferation of lung cancer cells. Molecular analysis further revealed that cir-ITCH acted as sponge of oncogenic miR-7 and miR-214 to enhance ITCH expression and thus suppressed the activation of Wnt/β-catenin signaling. Altogether, our results suggested that cir-ITCH may play an inhibitory role in lung cancer progression by enhancing its parental gene, ITCH, expression.

LGALS3 and AXIN1 gene variants playing role in the Wnt/ β-catenin signaling pathway are associated with mucinous component and tumor size in colorectal cancer

The Wnt pathway alterations have been identified in colorectal and many other cancer types. It has been reported that galectin-3 (which is encoded by the LGALS3 gene) alters the signaling mechanism in the Wnt/ β-catenin pathway by binding to β-catenin in colon and other cancers. AXIN1 is mainly responsible for the assembly of the β-catenin destruction complex in the Wnt pathway. This study investigated the relationship of rs4644 and rs4652 variants of the LGALS3 gene and rs214250 variants of the AXIN1 gene to histopathological and clinical properties. Our study included a total of 236 patients, of whom 119 had colorectal cancer (42 women, 77 men) and 117 were healthy controls. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and allele-specific oligonucleotide (ASO) PCR methods were used. In addition, the serum galectin-3 level was studied with the enzyme-linked immunosorbent assay (ELISA) method. For the rs4644 variant of the LGALS3 gene, the CC genotype a mucinous component was significantly more common than those without a mucinous component (p=0.026). C allele frequency of the rs214250 variant of the AXIN1 gene was significantly correlated to tumor size in the advanced tumor stage (p=0.022). The CCAACT haplotype was more common in colorectal cancer patients (p=0.022). Serum galectin-3 level was higher in the patient group compared to the control group (5.9± 0.69 ng/ml vs. 0.79±0.01 ng/ml; p<0.001). In conclusion, variants of LGALS3 and AXIN1 genes affect tumor sizes and the mucinous component via Wnt/ β-catenin pathway in the pathogenesis of colorectal cancer.

Mechanism of Wnt/β-catenin signaling pathway in enhanced malignant phenotype of non-small cell lung cancer induced by anti-angiogenesis therapy

OBJECTIVE

To study the mechanism of Wnt/β-catenin signaling pathway in the enhanced malignant phenotype of A549 cells of human non-small cell lung cancer induced by the anti-angiogenesis therapy.

METHODS

The siRNA technique was employed to inhibit the expression of vascular endothelial growth factor (VEGF) in A549 cells and simulate the clinical course of anti-angiogenesis therapy. Real-time PCR and western blot were used to study the change in the expression of Wnt/β-catenin signaling molecules at the mRNA and protein level respectively, as well as the effect on the epithelial mesenchymal transition in A549 cells. The proliferation and invasion abilities of tumor cells were detected to discuss the mechanism of Wnt/β-catenin signaling pathway in the enhanced malignant phenotype of non-small cell lung cancer induced by the anti-angiogenesis therapy.

RESULTS

The specific siRNA could significantly inhibit the expression of VEGF in cells to simulate the anti-angiogenesis therapy. Under the action of 50 nM VEGF siRNA, the proliferation ability of A549 significantly increased (P < 0.05). After being treated with VEGF siRNA, the invasion ability of cells increased. Twenty-four hours after the transcription of 50 nM siRNA into cells, the number of cells that come through the membrane was 278.3 ± 12.9. Compared with the Ctrl siRNA group, when VEGF was inhibited, the expression of β-catenin and Cyclin D1 increased by 86% and 55% respectively. Meanwhile, the expression of E-cadherin decreased, while the one of vimentin increased.

CONCLUSIONS

siRNA can significantly inhibit the expression of VEGF. For the anti-angiogenesis therapy, the inhibited expression of VEGF can activate the Wnt/β-catenin signaling pathway to cause the epithelial mesenchymal transition and then the enhanced malignant phenotype of non-small cell lung cancer.