MicroRNA-21 Promotes Glioblastoma Tumorigenesis by Down-regulating Insulin-like Growth Factor-binding Protein-3 (IGFBP3)

Despite advances in surgery, imaging, chemotherapy, and radiation, patients with glioblastoma multiforme (GBM), the most common histological subtype of glioma, have an especially dismal prognosis; >70% of GBM patients die within 2 years of diagnosis. In many human cancers, the microRNA miR-21 is overexpressed, and accumulating evidence indicates that it functions as an oncogene. Here, we report that miR-21 is overexpressed in human GBM cell lines and tumor tissue. Moreover, miR-21 expression in GBM patient samples is inversely correlated with patient survival. Knockdown of miR-21 in GBM cells inhibited cell proliferation in vitro and markedly inhibited tumor formation in vivo. A number of known miR-21 targets have been identified previously. By microarray analysis, we identified and validated insulin-like growth factor (IGF)-binding protein-3 (IGFBP3) as a novel miR-21 target gene. Overexpression of IGFBP3 in glioma cells inhibited cell proliferation in vitro and inhibited tumor formation of glioma xenografts in vivo. The critical role that IGFBP3 plays in miR-21-mediated actions was demonstrated by a rescue experiment, in which IGFBP3 knockdown in miR-21KD glioblastoma cells restored tumorigenesis. Examination of tumors from GBM patients showed that there was an inverse relationship between IGFBP3 and miR-21 expression and that increased IGFBP3 expression correlated with better patient survival. Our results identify IGFBP3 as a novel miR-21 target gene in glioblastoma and suggest that the oncogenic miRNA miR-21 down-regulates the expression of IGFBP3, which acts as a tumor suppressor in human glioblastoma.     

Fasting Enhances the Response of Glioma to Chemo- and Radiotherapy

Background

Glioma, including anaplastic astrocytoma and glioblastoma multiforme (GBM) are among the most commonly diagnosed malignant adult brain tumors. GBM is a highly invasive and angiogenic tumor, resulting in a 12 to 15 months median survival. The treatment of GBM is multimodal and includes surgical resection, followed by adjuvant radio-and chemotherapy. We have previously reported that short-term starvation (STS) enhances the therapeutic index of chemo-treatments by differentially protecting normal cells against and/or sensitizing tumor cells to chemotoxicity.

Methodology and Principal Findings

To test the effect of starvation on glioma cells in vitro, we treated primary mouse glia, murine GL26, rat C6 and human U251, LN229 and A172 glioma cells with Temozolomide in ad lib and STS mimicking conditions. In vivo, mice with subcutaneous or intracranial models of GL26 glioma were starved for 48 hours prior to radio- or chemotherapy and the effects on tumor progression and survival were measured. Starvation-mimicking conditions sensitized murine, rat and human glioma cells, but not primary mixed glia, to chemotherapy. In vivo, starvation for 48 hours, which causes a significant reduction in blood glucose and circulating insulin-like growth factor 1 (IGF-1) levels, sensitized both subcutaneous and intracranial glioma models to radio-and chemotherapy.

Conclusion

Starvation-induced cancer sensitization to radio- or chemotherapy leads to extended survival in the in vivo glioma models tested. These results indicate that fasting and fasting-mimicking interventions could enhance the efficacy of existing cancer treatments against aggressive glioma in patients.     

Cord Blood Stem Cell-Mediated Induction of Apoptosis in Glioma Downregulates X-Linked Inhibitor of Apoptosis Protein (XIAP)

Background

XIAP (X-linked inhibitor of apoptosis protein) is one of the most important members of the apoptosis inhibitor family. XIAP is upregulated in various malignancies, including human glioblastoma. It promotes invasion, metastasis, growth and survival of malignant cells. We hypothesized that downregulation of XIAP by human umbilical cord blood mesenchymal stem cells (hUCBSC) in glioma cells would cause them to undergo apoptotic death.

Methodology/Principal Findings

We observed the effect of hUCBSC on two malignant glioma cell lines (SNB19 and U251) and two glioma xenograft cell lines (4910 and 5310). In co-cultures of glioma cells with hUCBSC, proliferation of glioma cells was significantly inhibited. This is associated with increased cytotoxicity of glioma cells, which led to glioma cell death. Stem cells induced apoptosis in glioma cells, which was evaluated by TUNEL assay, FACS analyses and immunoblotting. The induction of apoptosis is associated with inhibition of XIAP in co-cultures of hUCBSC. Similar results were obtained by the treatment of glioma cells with shRNA to downregulate XIAP (siXIAP). Downregulation of XIAP resulted in activation of caspase-3 and caspase-9 to trigger apoptosis in glioma cells. Apoptosis is characterized by the loss of mitochondrial membrane potential and upregulation of mitochondrial apoptotic proteins Bax and Bad. Cell death of glioma cells was marked by downregulation of Akt and phospho-Akt molecules. We observed similar results under in vivo conditions in U251- and 5310-injected nude mice brains, which were treated with hUCBSC. Under in vivo conditions, Smac/DIABLO was found to be colocalized in the nucleus, showing that hUCBSC induced apoptosis is mediated by inhibition of XIAP and activation of Smac/DIABLO.

Conclusions/Significance

Our results indicate that downregulation of XIAP by hUCBSC treatment induces apoptosis, which led to the death of the glioma cells and xenograft cells. This study demonstrates the therapeutic potential of XIAP and hUCBSC to treat malignant gliomas.     

Antitumor Activity of a Polypyridyl Chelating Ligand: In Vitro and In Vivo Inhibition of Glioma

Glioblastoma multiforme is an extremely aggressive and invasive form of central nervous system tumor commonly treated with the chemotherapeutic drug Temozolomide. Unfortunately, even with treatment, the median survival time is less than 12 months. 2,9-Di-sec-butyl-1,10-phenanthroline (SBP), a phenanthroline-based ligand originally developed to deliver gold-based anticancer drugs, has recently been shown to have significant antitumor activity in its own right. SBP is hypothesized to initiate tumor cell death via interaction with non-DNA targets, and considering most glioblastoma drugs kill tumors through DNA damage processes, SBP was tested as a potential novel drug candidate against glial-based tumors. In vitro studies demonstrated that SBP significantly inhibited the growth of rodent GL-26 and C6 glioma cells, as well as human U-87, and SW1088 glioblastomas/astrocytomas. Furthermore, using a syngeneic glioma model in mice, in vivo administration of SBP significantly reduced tumor volume and increased survival time. There was no significant toxicity toward nontumorigenic primary murine and human astrocytes in vitro, and limited toxicity was observed in ex vivo tissues obtained from noncancerous mice. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining and recovery assays suggest that SBP induces apoptosis in gliomas. This exploratory study suggests SBP is effective in slowing the growth of tumorigenic cells in the brain while exhibiting limited toxicity to normal cells and tissues and should therefore be further investigated for its potential in glioblastoma treatment.     

Modulation of microRNA editing,expression and processing by ADAR2 deaminase in glioblastoma

BackgroundADAR enzymes convert adenosines to inosines within double-stranded RNAs, including microRNA (miRNA) precursors, with important consequences on miRNA retargeting and expression. ADAR2 activity is impaired in glioblastoma and its rescue has anti-tumoral effects. However, how ADAR2 activity may impact the miRNome and the progression of glioblastoma is not known.ResultsBy integrating deep-sequencing and array approaches with bioinformatics analyses and molecular studies, we show that ADAR2 is essential to edit a small number of mature miRNAs and to significantly modulate the expression of about 90 miRNAs in glioblastoma cells. Specifically, the rescue of ADAR2 activity in cancer cells recovers the edited miRNA population lost in glioblastoma cell lines and tissues, and rebalances expression of onco-miRNAs and tumor suppressor miRNAs to the levels observed in normal human brain. We report that the major effect of ADAR2 is to reduce the expression of a large number of miRNAs, most of which act as onco-miRNAs. ADAR2 can edit miR-222/221 and miR-21 precursors and decrease the expression of the corresponding mature onco-miRNAs in vivo and in vitro, with important effects on cell proliferation and migration.ConclusionsOur findings disclose an additional layer of complexity in miRNome regulation and provide information to better understand the impact of ADAR2 editing enzyme in glioblastoma. We propose that ADAR2 is a key factor for maintaining edited-miRNA population and balancing the expression of several essential miRNAs involved in cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0575-z) contains supplementary material, which is available to authorized users.     

ITPRIP promotes glioma progression by linking MYL9 to DAPK1 inhibition

Epigenetic gene silencing of the tumor suppressor death-associated protein kinase 1 (DAPK1) is implicated in the progression of malignant gliomas. However, the mechanism underlying the repression of DAPK1 in gliomas remains elusive. In this study, we identified the existence of DAPK1-inositol 1,4,5-trisphosphate receptor (IP₃R)-interacting protein (ITPRIP) -myosin regulatory light polypeptide 9 (MYL9) complex in malignant glioma cells. Lentivirus co-infection and coimmunoprecipitation showed that ITPRIP bound with the death domain (DD) of DAPK1 in vitro. Further, dissociating ITPRIP-DAPK1 interaction inhibited glioma tumor growth in vitro but not in vivo. Moreover, knockdown of ITPRIP or DAPK1 impaired the ternary complex formation, whereas MYL9 knockdown did not affect ITPRIP-DAPK1 association. We further found that ITPRIP recruited MYL9 to the kinase domain (KD) of DAPK1, and in turn impeded the phosphorylation of MYL9. Accordingly, interference of ITPRIP enhanced the suppressive effects of DAPK1-KD on glioma progression both in vitro and in vivo. Our results demonstrate that ITPRIP plays a crucial role in the inhibition of DAPK1 and enhancement of tumorigenic properties of malignant glioma cells.     

PIMREG expression level predicts glioblastoma patient survival and affects temozolomide resistance and DNA damage response

PIMREG expression strongly correlates with cellular proliferation in both malignant and normal cells. Throughout embryo development, PIMREG expression is prominent in the central nervous system. Recent studies have described elevated PIMREG expression in different types of tumors, which correlates with patient survival and tumor aggressiveness. Given the emerging significance of PIMREG in carcinogenesis and its putative role in the context of the nervous system, we investigated the expression and function of PIMREG in gliomas, the most common primary brain tumors. We performed an extensive analysis of PIMREG expression in tumors samples from glioma patients. We then assessed the effects of PIMREG silencing and overexpression on the sensitivity of glioblastoma cell lines treated with genotoxic agents commonly used for treating patients and assessed for treatment response, proliferation and migration. Our analysis shows that glioblastoma exhibits the highest levels of PIMREG expression among all cancers analyzed and that elevated PIMREG expression is a biomarker for glioma progression and patient outcome. Moreover, PIMREG is induced by genotoxic agents, and its silencing renders glioblastoma cells sensitive to temozolomide treatment and affects ATR- and ATM-dependent signaling. Our data demonstrate that PIMREG is involved in DNA damage response and temozolomide resistance of glioblastoma cells and further supports a role for PIMREG in tumorigenesis.     

RHPS4 G-Quadruplex Ligand Induces Anti-Proliferative Effects in Brain Tumor Cells

Background

Telomeric 3′ overhangs can fold into a four-stranded DNA structure termed G-quadruplex (G4), a formation which inhibits telomerase. As telomerase activation is crucial for telomere maintenance in most cancer cells, several classes of G4 ligands have been designed to directly disrupt telomeric structure.

Methods

We exposed brain tumor cells to the G4 ligand 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl]acridinium methosulfate (RHPS4) and investigated proliferation, cell cycle dynamics, telomere length, telomerase activity and activated c-Myc levels.

Results

Although all cell lines tested were sensitive to RHPS4, PFSK-1 central nervous system primitive neuroectodermal cells, DAOY medulloblastoma cells and U87 glioblastoma cells exhibited up to 30-fold increased sensitivity compared to KNS42 glioblastoma, C6 glioma and Res196 ependymoma cells. An increased proportion of S-phase cells were observed in medulloblastoma and high grade glioma cells whilst CNS PNET cells showed an increased proportion of G1-phase cells. RHPS4-induced phenotypes were concomitant with telomerase inhibition, manifested in a telomere length-independent manner and not associated with activated c-Myc levels. However, anti-proliferative effects were also observed in normal neural/endothelial cells in vitro and ex vivo.

Conclusion

This study warrants in vivo validation of RHPS4 and alternative G4 ligands as potential anti-cancer agents for brain tumors but highlights the consideration of dose-limiting tissue toxicities.     

Temozolomide modifies caveolin-1 expression in experimental malignant gliomas in vitro and in vivo

BACKGROUND: Caveolin-1 is a protein that displays promotive versus preventive roles in cancer progression according to circumstances. Temozolomide (TMZ) is the standard chemotherapeutic to treat glioma patients. The present work aims to characterizeTMZ-induced effects on caveolin-1 expression in glioma cells. METHODS: Human astroglioma (U373 and T98G) and oligodendroglioma (Hs683) cell lines were used in vitro as well as in vivo orthotopic xenografts (Hs683 and U373) into the brains of immunocompromisedmice. In vitro TMZ-induced effects on protein expression and cellular localization were determined by Western blot analysis and on the actin cytoskeleton organization by means of immunofluorescence approaches. In vivo TMZ-induced effects in caveolin-1 expression in human glioma xenografts were monitored by means of immunohistochemistry. RESULTS: TMZ modified caveolin-1 expression and localization in vitro and in vivo after an administration schedule that slightly, if at all, impaired cell growth characteristics in vitro. Caveolin-1 by itself (at a 100-ng/ml concentration) was able to significantly reduce invasiveness (Boyden chambers) of the three human glioma cell lines. The TMZ-inducedmodification in caveolin-1 expression in flotation/raft compartments was paralleled by altered Cyr61 and β₁ integrin expression, two elements that have already been reported to collaborate with caveolin-1 in regulating glioma cell biology, and all these features led to profound reorganization of the actin cytoskeleton. An experimental Src kinase inhibitor, AZD0530, almost completely antagonized the TMZ-induced modulation in caveolin-1 expression. CONCLUSION: TMZ modifies caveolin-1 expression in vitro and in vivo in glioma cells, a feature that directly affects glioma cell migration properties.     

Effects of Dual Targeting of Tumor Cells and Stroma in Human Glioblastoma Xenografts with a Tyrosine Kinase Inhibitor against c-MET and VEGFR2

Anti-angiogenic treatment of glioblastoma with Vascular Endothelial Growth Factor (VEGF)- or VEGF Receptor 2 (VEGFR2) inhibitors normalizes tumor vessels, resulting in a profound radiologic response and improved quality of life. This approach however does not halt tumor progression by diffuse infiltration, as this phenotype is less angiogenesis dependent. Combined inhibition of angiogenesis and diffuse infiltrative growth would therefore be a more effective treatment approach in these tumors. The HGF/c-MET axis is important in both angiogenesis and cell migration in several tumor types including glioma. We therefore analyzed the effects of the c-MET- and VEGFR2 tyrosine kinase inhibitor cabozantinib (XL184, Exelixis) on c-MET positive orthotopic E98 glioblastoma xenografts, which routinely present with angiogenesis-dependent areas of tumor growth, as well as diffuse infiltrative growth. In in vitro cultures of E98 cells, cabozantinib effectively inhibited c-MET phosphorylation, concomitant with inhibitory effects on AKT and ERK1/2 phosphorylation, and cell proliferation and migration. VEGFR2 activation in endothelial cells was also effectively inhibited in vitro. Treatment of BALB/c nu/nu mice carrying orthotopic E98 xenografts resulted in a significant increase in overall survival. Cabozantinib effectively inhibited angiogenesis, resulting in increased hypoxia in angiogenesis-dependent tumor areas, and induced vessel normalization. Yet, tumors ultimately escaped cabozantinib therapy by diffuse infiltrative outgrowth via vessel co-option. Of importance, in contrast to the results from in vitro experiments, in vivo blockade of c-MET activation was incomplete, possibly due to multiple factors including restoration of the blood-brain barrier resulting from cabozantinib-induced VEGFR2 inhibition. In conclusion, cabozantinib is a promising therapy for c-MET positive glioma, but improving delivery of the drug to the tumor and/or the surrounding tissue may be needed for full activity.     

Basal caspase activity promotes migration and invasiveness in glioblastoma cells

Glioblastomas, the most malignant of all brain tumors, are characterized by cellular resistance to apoptosis and a highly invasive growth pattern. These factors contribute to the poor response of glioblastomas to radiochemotherapy and prevent their complete neurosurgical resection. However, the driving force behind the distinct motility of glioma cells is only partly understood. Here, we report that in the absence of cellular stress and proapoptotic stimuli, human glioblastoma cells exhibit a constitutive activation of caspases in vivo and in vitro. The inhibition of caspases by various peptide inhibitors decreases the migration of cells in scrape motility assays and the invasiveness of cells in spheroid assays. Similarly, specific small interfering RNA- or antisense-mediated down-regulation of caspase-3 and caspase-8 results in an inhibition of the migratory potential of glioma cells. The constitutive caspase-dependent motility of glioblastoma cells is independent of CD95 activation and it is not mediated by mitogen-activated protein/extracellular signal-regulated kinase kinase signaling. The basal caspase activity is accompanied by a constant cleavage of the motility-associated gelsolin protein, which may contribute to the caspase-mediated promotion of migration and invasiveness in glioblastoma cells. Our results suggest that the administration of low doses of caspase inhibitors that block glioma cell motility without affecting the execution of apoptotic cell death may be exploited as a novel strategy for the treatment of glioblastomas.     

Soluble LRIG2 Ectodomain Is Released from Glioblastoma Cells and Promotes the Proliferation and Inhibits the Apoptosis of Glioblastoma Cells In Vitro and In Vivo in a Similar Manner to the Full-Length LRIG2

The human leucine-rich repeats and immunoglobulin-like domains (LRIG) gene family contains LRIG1, 2 and 3, encoding integral membrane proteins with an ectodomain, a transmembrane domain and a cytoplasmic tail. LRIG1 negatively regulates multiple receptor tyrosine kinases signaling including the epidermal growth factor receptor (EGFR) and is a proposed tumor suppressor. The soluble LRIG1 ectodomain is demonstrated to be shed naturally and inhibit the progression of glioma. However, little is known regarding the functions of LRIG2. In oligodendroglioma, LRIG2 expression is associated with poor survival, suggesting that LRIG2 might have different functions compared with LRIG1. Since soluble LRIG1 ectodomain has a similar function to the full-length LRIG1, we hypothesize that the different roles exerted by LRIG2 and LRIG1 result from the difference of their ectodomains. Here, we addressed the functions of LRIG2 and LRIG2 ectodomain in the proliferation and apoptosis of glioma and the possible underlying mechanisms. Firstly, we found that LRIG2 expression levels positively correlated with the grade of glioma. Further, we demonstrated for the first time that soluble LRIG2 ectodomain was capable of being released from glioblastoma cells and exerted a pro-proliferative effect. Overexpression of LRIG2 ectodomain promoted the proliferation and inhibited the apoptosis of glioblastoma cells in vitro and in vivo in a similar manner to the full-length LRIG2. Both full-length LRIG2 and LRIG2 ectodomain were found to physically interact with EGFR, enhance the activation of EGFR and its downstream PI3 K/Akt pathway. To our knowledge, this is the first report demonstrating that soluble LRIG2 ectodomain is capable of being released from glioblastoma cells and exerts a similar role to the full-length LRIG2 in the regulation of EGFR signaling in the progression of glioblastoma. LRIG2 ectodomain, with potent pro-tumor effects, holds promise for providing a new therapeutic target for the treatment of glioblastoma.     

A novel tumor-promoting mechanism of IL6 and the therapeutic efficacy of tocilizumab: Hypoxia-induced IL6 is a potent autophagy initiator in glioblastoma via the p-STAT3-MIR155-3p-CREBRF pathway

Hypoxia induces protective autophagy in glioblastoma cells and new therapeutic avenues that target this process may improve the outcome for glioblastoma patients. Recent studies have suggested that the autophagic process is upregulated in glioblastomas in response to extensive hypoxia. Hypoxia also induces the upregulation of a specific set of proteins and microRNAs (miRNAs) in a variety of cell types. IL6 (interleukin 6), an inflammatory autocrine and paracrine cytokine that is overexpressed in glioblastoma, has been reported to be a biomarker for poor prognosis because of its tumor-promoting effects. Here, we describe a novel tumor-promoting mechanism of IL6, whereby hypoxia-induced IL6 acts as a potent initiator of autophagy in glioblastoma via the phosphorylated (p)-STAT3-MIR155-3p pathway. IL6 and p-STAT3 levels correlated with the abundance of autophagic cells and HIF1A levels in human glioma tissues and with the grade of human glioma, whereas inhibition of exogenous or endogenous IL6 repressed autophagy in glioblastoma cells in vitro. Knockdown of endogenous MIR155-3p inhibited IL6-induced autophagy, and enforced expression of MIR155-3p restored the anti-autophagic activity of IL6 inhibitors. We show that the hypoxia-IL6-p-STAT3-MIR155-3p-CREBRF-CREB3-ATG5 pathway plays a central role in malignant glioma progression, with blockade of the IL6 receptor by tocilizumab demonstrating a certain level of therapeutic efficacy in a xenograft model in vivo, especially in combination with temozolomide. Moreover, tocilizumab inhibits autophagy by promoting tumor apoptosis. Collectively, our findings provide new insight into the molecular mechanisms underlying hypoxia-induced glioma cell autophagy and point toward a possible efficacious adjuvant therapy for glioblastoma patients.     

Bmi-1 Promotes Glioma Angiogenesis by Activating NF-κB Signaling

Angiogenesis in glioma is associated with the poor prognosis of the disease and closely correlates with the highly invasive phenotype of glioma cells, which represents the most challenging impediment against the currently glioma treatments. Bmi-1, an onco-protein, has been implicated in the progression of various human cancers, including gliomas, whereas its role in glioma angiogenesis remains unclear. Our current study examined the effects of Bmi-1 on glioma angiogenesis in vitro as well as in vivo. We found that overexpression of Bmi-1 enhanced, whereas knockdown of Bmi-1 diminished, the capability of glioma cells to induce tubule formation and migration of endothelial cells and neovascularization in chicken chorioallantoic membrane. In vivo, Bmi-1 overexpression and knockdown, respectively, promoted and inhibited angiogenesis in orthotopically transplanted human gliomas. Furthermore, NF-κB activity and VEGF-C expression was induced by Bmi-1 overexpression, whereas Bmi-1 knockdown attenuated NF-κB signaling and decreased VEGF-C expression. Additionally suppression of NF-κB activity using a specific chemical inhibitor abrogated the NF-κB activation and the pro-angiogenic activities of glioma cells. Together, our data suggest that Bmi-1 plays an important role in glioma angiogenesis and therefore could represent a potential target for anti-angiogenic therapy against the disease.     

Knockdown of FRAT1 Expression by RNA Interference Inhibits Human Glioblastoma Cell Growth,Migration and Invasion

Background

FRAT1 positively regulates the Wnt/β-catenin signaling pathway by inhibiting GSK-3-mediated phosphorylation of β-catenin. It was originally characterized as a protein frequently rearranged in advanced T cell lymphoma, but has recently also been identified as a proto-oncogene involved in tumorigenesis. Our previous studies showed that FRAT1 was dramatically overexpressed in gliomas and its expression level was significantly increased along with clinicopathological grades.

Methods

In the current study, we used RT-PCR and Western blotting to assess the mRNA and protein levels of FRAT1 in three glioma cell lines. In addition, to evaluate its functional role in gliomas, we examined the effects of FRAT1 knockdown on proliferation, migration and invasion in vitro and tumor growth in vivo using glioblastoma U251 cells and RNAi.

Results

FRAT1 was highly expressed in all three glioma cell lines. RNAi-mediated down-regulation of endogenous FRAT1 in human glioblastoma U251 cells resulted in suppression of cell proliferation, arrest of cell cycle, inhibition of cell migration and invasion in vitro. Moreover, FRAT1 depletion significantly impaired tumor xenograft growth in nude mice.

Conclusions

Our results highlight the potential role of FRAT1 in tumorigenesis and progression of glioblastoma. These findings provide a biological basis for FRAT1 as a potential molecular marker for improved pathological grading and as a novel candidate therapeutic target for glioblastoma management.     

Human Sarcoma Growth Is Sensitive to Small-Molecule Mediated AXIN Stabilization

Sarcomas are mesenchymal tumors showing high molecular heterogeneity, reflected at the histological level by the existence of more than fifty different subtypes. Genetic and epigenetic evidences link aberrant activation of the Wnt signaling to growth and progression of human sarcomas. This phenomenon, mainly accomplished by autocrine loop activity, is sustained by gene amplification, over-expression of Wnt ligands and co-receptors or epigenetic silencing of endogenous Wnt antagonists. We previously showed that pharmacological inhibition of Wnt signaling mediated by Axin stabilization produced in vitro and in vivo antitumor activity in glioblastoma tumors. Here, we report that targeting different sarcoma cell lines with the Wnt inhibitor/Axin stabilizer SEN461 produces a less transformed phenotype, as supported by modulation of anchorage-independent growth in vitro. At the molecular level, SEN461 treatment enhanced the stability of the scaffold protein Axin1, a key negative regulator of the Wnt signaling with tumor suppressor function, resulting in downstream effects coherent with inhibition of canonical Wnt signaling. Genetic phenocopy of small molecule Axin stabilization, through Axin1 over-expression, coherently resulted in strong impairment of soft-agar growth. Importantly, sarcoma growth inhibition through pharmacological Axin stabilization was also observed in a xenograft model in vivo in female CD-1 nude mice. Our findings suggest the usefulness of Wnt inhibitors with Axin stabilization activity as a potentialyl clinical relevant strategy for certain types of sarcomas.