Catenin Axis Research Articles

MiR-375-3p/YWHAZ/β-catenin axis regulates migration, invasion, EMT in gastric cancer cells.

YWHAZ (14-3-3ζ) plays crucial roles in regulating proliferation, apoptosis, migration, and invasion of gastric cancer (GC) cells. However, its extensive roles and potential mechanisms in GC cells remain unknown, and need to be researched deeply. In this study, we focus on the role of miR-375/YWHAZ axis in migration, invasion and epithelial-to-mesenchymal transition (EMT) of GC cells. YWHAZ level was assessed by western blot and qPCR assays in GC cells. Scratch and transwell assays were used to determine the migration and invasion of GC cells. The protein levels of correlative molecules were detected by western blot. The regulation of miR-375 on the expression of its target gene YWHAZ was verified by dual-luciferase report system. According to the results, knockdown of YWHAZ inhibited the migration, invasion and EMT of GC cells. Moreover, silencing of YWHAZ restrained the activation of wnt/β-catenin signalling pathway. YWHAZ was confirmed to be a target gene of miR-375, and its expression was regulated by miR-375 in GC cells. Transfection of miR-375 inhibitor promoted the migration, invasion, EMT and activation of wnt/β-catenin pathway in GC cells, which was suppressed by inhibition of YWHAZ. Taken together, this study suggests that miR-375/YWHAZ axis may be served as a novel therapeutic target for GC patients.

Suppression of the SDF‑1/CXCR4/β‑catenin axis contributes to bladder cancer cell growth inhibition invitro and invivo.

Previous studies have found that the activation of stromal cell‑derived factor‑1 (SDF‑1)/CXC chemokine receptor‑4 (CXCR4)/β‑catenin signaling is associated with biological malignant potential in cancers. However, its function has been rarely reported in the progression of bladder cancer (BCa). The aim of the present study was to investigate the association of SDF‑1/CXCR4 signaling and β‑catenin in regards to BCa cell proliferation, colony formation, migration and invasion. The methods used were MTS, colony formation, and Transwell migration and invasion assays which were performed in SW780 cells following treatment with the CXCR4 antagonist AMD3465, SDF‑1, the β‑catenin antagonist FH535, AMD3465+SDF‑1 or FH535+SDF‑1. The mRNA and protein levels were assayed by RT‑qPCR and western blotting, respectively. The effect of AMD3465 on SW780 cell xenograft growth invivo was evaluated using a nude mouse model. According to our results, human BCa SW780 cells were identified as having high expression of CXCR4 and β‑catenin. Subsequently, we found that both CXCR4 and β‑catenin antagonists could significantly inhibit the proliferation, colony formation, migration and invasion of SW780 cells. Notably, SDF‑1 could reverse the inhibitory effects of AMD3465 and FH535 on proliferation, colony formation, migration and invasion in SW780 cells. In AMD3465‑treated SW780 cells, the expression of c‑myc was significantly upregulated, and E‑cadherin was downregulated in the presence of SDF‑1. Furthermore, the tumor volume and average weight in the AMD3465‑treated group were evidently less than these parameters in the control group, indicating that AMD3465 can inhibit SW780 cell growth invivo. In conclusion, targeting the SDF‑1/CXCR4/β‑catenin axis may be a potential therapeutic target for suppressing BCa progression.

MicroRNA-185 inhibits the growth and proliferation of osteoblasts in fracture healing by targeting PTH gene through down-regulating Wnt/β -catenin axis: In an animal experiment

Fracture healing is a repair process of a mechanical discontinuity loss of force transmission, and pathological mobility of bone. Increasing evidence suggests that microRNA (miRNA) could regulate chondrocyte, osteoblast, and osteoclast differentiation and function, indicating miRNA as key regulators of bone formation, resorption, remodeling, and repair. Hence, during this study, we established a right femur fracture mouse model to explore the effect microRNA-185 (miR-185) has on osteoblasts in mice during fracture healing and its underlying mechanism. After successfully model establishment, osteoblasts were extracted and treated with a series of mimics or inhibitors of miR-185, or siRNA against PTH. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analysis were performed to determine the levels of miR-185, PTH, β-catenin and Wnt5b. Cell viability, cycle distribution and apoptosis were detected by means of MTT and flow cytometry assays. Dual luciferase reporter gene assay verified that PTH is a target gene of miR-185. Osteoblasts transfected with miR-185 mimics or siRNA against PTH presented with decreased levels of PTH, β-catenin and Wnt5b which indicated that miR-185 blocks the Wnt/β -catenin axis by inhibiting PTH. Moreover, miR-185 inhibitors promoted the osteoblast viability and reduced apoptosis with more cells arrested at the G1 stage. MiR-185 mimics were observed to have inhibitory effects on osteoblasts as opposed to those induced by miR-185 inhibitors. Above key results indicated that suppression of miR-185 targeting PTH could promote osteoblast growth and proliferation in mice during fracture healing through activating Wnt/β -catenin axis.

IRS1/β-Catenin Axis Is Activated and Induces MYC Expression in Acute Lymphoblastic Leukemia Cells.

Insulin-like growth factor 1 (IGF1) and its receptor IGF1R regulate normal cell growth and contribute to cell transformation through activation of downstream signaling pathways. In fibroblast cells, insulin receptor substrate 1 (IRS1), through IGF1 signaling, was found to be the key protein for nuclear translocation of β-catenin and MYC transcription activation. We herein investigated the IRS1/β-catenin axis in acute lymphoblastic leukemia (ALL) cells. Samples were obtained from 45 patients with ALL and 13 healthy donors. ALL cell lines were used. Gene expression was measured by quantitative PCR. Protein expression, associations, and cellular localization were evaluated by immunoprecipitation, subcellular fractionation, and confocal microscopy. Cells were submitted to IGF1 stimulation and/or IGF1R pharmacological inhibition (OSI-906). IRS1, β-catenin, and MYC mRNA expression were significantly elevated in ALL patients, compared to normal controls. MYC mRNA expression positively correlated with β-catenin and IRS1. Increased age and MYC expression negatively affected overall survival by univariate analysis. Total and phospho-IGF1R and IRS1, MYC and β-catenin protein expression were higher in ALL cells, compared to normal peripheral blood mononuclear cells (PBMC). IRS1 and β-catenin were found to be colocalized in the nuclei and the cytoplasm of ALL cell lines, whereas both proteins were only slightly detected in the cytoplasm of normal PBMC. In Jurkat cells, a constitutive IRS1 and β-catenin protein interaction were observed; OSI-906 treatment decreased IGF1R tyrosine phosphorylation, IRS1 expression and phosphorylation, nuclear translocation of β-catenin, IRS1 and β-catenin association, and MYC protein expression. In conclusion, the IRS1/β-catenin axis is activated in ALL cells. J. Cell. Biochem. 118: 1774-1781, 2017. © 2016 Wiley Periodicals, Inc.

A caveolin-dependent and PI3K/AKT-independent role of PTEN in β-catenin transcriptional activity.

Loss of the tumour suppressor PTEN is frequent in human melanoma, results in MAPK activation, suppresses senescence and mediates metastatic behaviour. How PTEN loss mediates these effects is unknown. Here we show that loss of PTEN in epithelial and melanocytic cell lines induces the nuclear localization and transcriptional activation of β-catenin independent of the PI3K–AKT–GSK3β axis. The absence of PTEN leads to caveolin-1 (CAV1)-dependent β-catenin transcriptional modulation in vitro, cooperates with NRASQ61K to initiate melanomagenesis in vivo and induces efficient metastasis formation associated with E-cadherin internalization. The CAV1-β–catenin axis is mediated by a feedback loop in which β-catenin represses transcription of miR-199a-5p and miR-203, which suppress the levels of CAV1 mRNA in melanoma cells. These data reveal a mechanism by which loss of PTEN increases CAV1-mediated dissociation of β-catenin from membranous E-cadherin, which may promote senescence bypass and metastasis.

The 14-3-3σ/GSK3β/β-catenin/ZEB1 regulatory loop modulates chemo-sensitivity in human tongue cancer.

Here we demonstrated that chemotherapy induced 14-3-3σ expression in tongue cancer (TC) cells and overexpressed 14-3-3σ sensitized TC cells to chemotherapy especially in multidrug resistant TC (MDR-TC) cells. In agreement, 14-3-3σ knockdown enhanced resistance of TC cells to chemotherapy. Mechanically, we found 14-3-3σ physically bound to GSK3β in protein level and the binding inhibited β-catenin signaling. Coincidentally, chemotherapy as well as 14-3-3σ overexpression led to increase of GSK3β protein level. Increased GSK3β protein sensitized TC cells to chemotherapy. Moreover, deregulation of 14-3-3σ/GSK3β/β-catenin axis led to overexpressed ZEB1 in TC cells, especially in MDR-TC cells. As a negative feedback loop, ZEB1 bond to 14-3-3σ promoter to enhance promoter hypermethylation in TC cells. Promoter hypermethylation resulted into the decrease of 14-3-3σ expression. Importantly, a positive correlation was observed between 14-3-3σ and GSK3β protein expression in TC tissues from patients receiving chemotherapy. High levels of 14-3-3σ and GSK3β were associated with better prognosis in TC patients.

Abstract P1-07-04: A novel bioactive approach to inhibit leptin-induced epithelial-mesenchymal transition in breast cancer

Abstract Introduction: Molecular effects of obesity, a well-established risk factor for breast cancer progression, are mediated by adipocytokine leptin. Recent studies from our lab reveal that leptin induces epithelial-mesenchymal transition (EMT) and tumorsphere formation via concomitant activation of Akt/GSK3b and MTA1/Wnt1 signaling axes leading to β catenin activation. Given the important role of leptin in breast cancer growth and metastasis, novel strategies to antagonize biological effects of leptin are much desired. We showed previously that honokiol, a bioactive polyphenol from Magnolia grandiflora, inhibits breast carcinogenesis. The present study provides first evidence for the efficacy of honokiol against oncogenic effects of leptin including EMT. Methods: Efficacy of honokiol to inhibit oncogenic effects of leptin was evaluated by using clonogenicity, anchorage–independent growth, matrigel-invasion and spheroid-migration assays. RT-PCR, western blot and immunofluorescence analyses were used to examine the molecular changes associated with EMT as well as underlying molecular pathways. Functional importance of MTA1/Wnt1/ β catenin axis was examined by using overexpression, phospho-deficient constructs and specific inhibitors. Finally, mouse xenografts, immuniohistochemical, RT-PCR and western blot analysis of tumors was used. Results: Honokiol treatment circumvents leptin-induced EMT-associated phenotypic changes. A biochemical hallmark of EMT is loss of expression of epithelial markers with a concurrent increase in mesenchymal marker expression. Honokiol elicits increased expression of E-cadherin, occludin and keratin-18 (epithelial markers) and decreased expression of vimentin, fibronectin and N-cadherin (mesenchymal markers) in leptin-treated cells providing molecular evidence for reversal of EMT. Honokiol also inhibits expression and nuclear translocation of transcriptional effectors of EMT; Snail, Slug, Zeb1 and Zeb2. Analysis of underlying molecular mechanisms reveals that Honokiol effectively inhibits leptin-induced MTA1/Wnt1/ β catenin axis. Furthermore, using nontoxic doses of honokiol, we show that honokiol treatment effectively inhibits leptin-induced breast tumorigenesis in vivo. Analysis of breast tumors show that honokiol treatment reverses leptin-associated signaling (MTA1/Wnt1/ β catenin axis) along with decreased expression of mesenchymal markers and increased expression of epithelial markers. Conclusions: In this study, we demonstrate for the first time that HNK is able to abolish leptin-induced EMT and provide in vitro and in vivo evidence for the integral role of a previously unrecognized crosstalk between honokiol and MTA1/Wnt1/ β catenin axis. Thus, HNK may be used as a non-toxic and non-endocrine rational therapeutic strategy for breast carcinoma in obese patients with high leptin levels. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-04.

Abstract 5497: A novel bioactive approach to inhibit leptin-induced epithelial-mesenchymal transition in breast cancer.

Abstract Introduction: Molecular effects of obesity, a well-established risk factor for breast cancer progression, are mediated by adipocytokine leptin. Recent studies from our lab reveal that leptin induces epithelial-mesenchymal transition (EMT) and tumorsphere formation via concomitant activation of Akt/GSK3β and MTA1/Wnt1 signaling axes leading to β-catenin activation. Given the important role of leptin in breast cancer growth and metastasis, novel strategies to antagonize biological effects of leptin are much desired. We showed previously that honokiol (HNK), a bioactive polyphenol from Magnolia grandiflora, inhibits breast carcinogenesis. The present study provides first evidence for the efficacy of HNK against oncogenic effects of leptin including EMT. Methods: Efficacy of HNK to inhibit oncogenic effects of leptin was evaluated by using clonogenicity, anchorage-independent growth, matrigel invasion and spheroid-migration assays. RT-PCR, Western blot and immunofluorescence analyses were used to examine the molecular changes associated with EMT as well as underlying molecular pathways. Functional importance of MTA1/Wnt1/β-catenin axis was examined by using overexpression, phospho-deficient constructs and specific inhibitors. Finally, mouse xenografts, immuniohistochemical, RT-PCR and Western blot analysis of tumors was used. Results: HNK treatment circumvents leptin-induced EMT-associated phenotypic changes. A biochemical hallmark of EMT is loss of expression of epithelial markers with a concurrent increase in mesenchymal marker expression. HNK elicits increased expression of E-cadherin, occludin and cytokeratin-18 (epithelial markers) and decreased expression of vimentin, fibronectin and N-cadherin (mesenchymal markers) in leptin-treated cells providing molecular evidence for reversal of EMT. HNK also inhibits expression and nuclear translocation of transcriptional effectors of EMT: Snail, Slug, Zeb1 and Zeb2. Analysis of underlying molecular mechanisms reveals that HNK effectively inhibits leptin-induced MTA1/Wnt1/β-catenin axis. Furthermore, using nontoxic doses of HNK, we show that HNK treatment effectively inhibits leptin-induced breast tumorigenesis in vivo. Analysis of breast tumors show that HNK treatment reverses leptin-associated signaling (MTA1/Wnt1/β-catenin axis) along with decreased expression of mesenchymal markers and increased expression of epithelial markers. Conclusions: In this study, we demonstrate for the first time that HNK is able to abolish leptin-induced EMT and provide in vitro and in vivo evidence for the integral role of a previously unrecognized crosstalk between honokiol and MTA1/Wnt1/ β catenin axis. Thus, HNK may be used as a non-toxic and non-endocrine rational therapeutic strategy for breast carcinoma in obese patients with high leptin levels. Citation Format: Dimiter B. Avtanski, Arumugam Nagalingam, Panjamurthy Kuppusamy, Neeraj K. Saxena, Dipali Sharma. A novel bioactive approach to inhibit leptin-induced epithelial-mesenchymal transition in breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5497. doi:10.1158/1538-7445.AM2013-5497

MiR‐197 induces epithelial–mesenchymal transition in pancreatic cancer cells by targeting p120 catenin

Invasive ductal adenocarcinoma (IDA) of the pancreas manifests poor prognosis due to the early invasion and distant metastasis. In contrast, intraductal papillary mucinous adenoma or carcinoma (IPMA or IPMC) reveals better clinical outcomes. Various molecular mechanisms contribute to these differences but entire picture is still unclear. Recent researches emphasized the important role of miRNA in biological processes including cancer invasion and metastasis. We previously described that miR-126 is down-regulated in IDA compared with IPMA or IPMC, and miR-126 regulates the expression of invasion related molecule disintegrin and metalloproteinase domain-containing protein 9 (ADAM9). Assessing the difference of miRNA expression profiles of IDA, IPMA, and IPMC, we newly identified miR-197 as an up-regulated miRNA specifically in IDA. Expression of miR-197 in pancreatic cancer cells resulted in the induction of epithelial-mesenchymal transition (EMT) along with the down-regulation of p120 catenin which is a putative target of miR-197. Direct interaction between miR-197 and p120 catenin mRNA sequence was confirmed by 3'UTR assay, and knockdown of p120 catenin recapitulated EMT induction in pancreatic cancer cells. In situ hybridization of miR-197 and immunohistochemistry of p120 catenin showed mutually exclusive patterns suggesting pivotal role of miR-197 in the regulation of p120 catenin. This miR-197/p120 catenin axis could be a novel therapeutic target.

Lenalidomide Suppresses 5′-Cap-Independent C-MYC Translation in Multiple Myeloma Cells

Abstract 3943 Background:Immunomodulatory drugs (IMiDs) are highly active in the treatment of multiple myeloma (MM). Blockade of the Wnt-GSK3β-beta catenin axis and suppression of eIF4E-C/EBPβ-dependent IRF4 expression were previously shown to mediate some of the IMiDs cytotoxic effects. In particular, cereblon (CRBN), an adaptor protein of the Cul4A-DDB1-ROC1 ubiquitin E3 ligase complex, was recently identified as an essential requirement for IMiDs anti-MM activity. In the present study, we examined how lenalidomide treatment modifies MM cells ubiquitome downstream of the Cul4A-DDB1-CRBN E3 ligase complex with the intent to identify novel molecular targets mediating IMiDs anti-MM effects. Methods and Results:Ubiquitin-proteome pull-down using Tandem Ubiquitin Binding Entity (TUBE, Lifesensors) coupled with quantitative mass-spectroscopy based proteomics (iTRAQ) was performed to identify modification to OPM2 cells ubiquitin-proteome induced by lenalidomide (10 μM for 24 hours) versus vehicle control treatment. Among the differentially modified ubiquitilated targets, histone family members H4, H2A.Z, H2B (known substrates of the Cullin-Ring Ub E3 ligases) and the 40S ribosomal proteins RPS25 and RPS26 were more than 2 fold increased in lenalidomide treated samples. Ribosomal protein RPS25 is required for internal ribosomal entry site (IRES) and 5′-cap-independent proteosynthesis. To examine the function of RPS25 in MM, siRNA-KD experiments were carried out in 2 human MM cell lines (OPM2 and MM1S). RPS25 silencing significantly (30–40%) reduced MM cells viability (MTT assay) when compared to non-targeting siRNA controls. Of interest, MM cells surviving RPS25 silencing were more resistant to IMIDs with approximately 20 to 30% reduction in lenalidomide induced cells death (Annexin V staining and MTT assay). Since, the 5′ UTR of c-myc is known to contain an IRES segement and c-myc translation can therefore be initiated by internal ribosome entry (RPS25 mediated) as well as by cap-dependent mechanisms, we next examined whether lenalidomide may downregulate c-myc through an IRF4-independent and rather RPS25-IRES dependent mechanism. Following 4 hours exposure to lenalidomide, C-MYC protein was significantly downregulated (western blot analysis) in OPM2 and MM1S cells, with no changes to IRF4 (protein or mRNA) or c-myc mRNA (qRT-PCR) at this early time point. No changes were observed in IRF4 until 24–48 hours of treatment with lenalidomide, findings consistent with an IRF4-independent C-MYC downregulation. Using the bicistronic (pRMF) luciferase reporter plasmid in which the upstream cistron encodes a Renilla luciferase translated in a cap-dependent manner, and the downstream cistron encoding a firefly luciferase translated in a cap-independent manner because of c-myc IRES insertion between the two cistrons, we examined whether treatment with lenalidomide modifies c-myc IRES ribosomal entry and translation. Following lenalidomide treatment, MM1S-pRMF transfected cells had a significant reduction in c-myc cap-independent translation as indicated by the reduction in the firely/renilla luminescence ratio. These findings were further supported by the use of the m-TOR inhibitor Rapamycin, an inhibitor of cap-dependent protein translation. Co-treatment of MM1S and OPM2 cells for 4 hours with the combination of Rapamycin (10 nM) and lenalidomide (10 μM) resulted in further reduction in C-MYC protein levels compared to either drugs alone. These results are consistent with an independent and additive (5′-cap-dependent with Rapamycin and independent with lenalidomide) rather than epistatic (both 5′-cap dependent) effects on c-myc translation. Conclusions:Taken together our data indicate that treatment with lenalidomide suppresses c-myc translation in an IRF4/5′-cap-translation independent mechanism (early time point), an effect possibly resulting from a Cul4a-CRBN regulation of RPS25, a key protein-mediating ribosomal entry. Disclosures:Neri:Johnson ans Johnson: Research Funding. Bahlis:Johnson and Johnson: Honoraria, Research Funding; Celgene: Honoraria.