Clinicopathological features and expression of regulatory mechanism of the Wnt signaling pathway in colorectal sessile serrated adenomas/polyps with different syndrome types

BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide,with the fourth highest mortality among all cancers.Reportedly,in addition to adenomas,serrated polyps,which account for 15%-30%of CRCs,can also develop into CRCs through the serrated pathway.Sessile serrated adenomas/polyps(SSAs/Ps),a type of serrated polyps,are easily misdiagnosed during endoscopy.AIM To observe the difference in the Wnt signaling pathway expression in SSAs/Ps patients with different syndrome types.METHODS From January 2021 to December 2021,patients with SSAs/Ps were recruited from the Endoscopy Room of Shanghai Traditional Chinese Medicine-Integrated Hospital,affiliated with Shanghai University of Traditional Chinese Medicine.Thirty cases each of large intestine damp-heat(Da-Chang-Shi-Re,DCSR)syndrome and spleen-stomach weakness(Pi-Wei-Xu-Ruo)syndrome were reported.Baseline comparison of the general data,typical tongue coating,colonoscopy findings,and hematoxylin and eosin findings was performed in each group.The expression of the Wnt pathway-related proteins,namelyβ-catenin,adenomatous polyposis coli,and mutated in colorectal cancer,were analyzed using immunohistochemistry.RESULTS Significant differences were observed with respect to the SSAs/Ps size between the two groups of patients with different syndrome types(P=0.001).The other aspects did not differ between the two groups.The Wnt signaling pathway was activated in patients with SSAs/Ps belonging to both groups,which was manifested asβ-catenin protein translocation into the nucleus.However,SSAs/Ps patients with DCSR syndrome had more nucleation,higherβ-catenin expression,and negative regulatory factor(adenomatous polyposis coli and mutated in colorectal cancer)expression(P<0.0001)than SSA/P patients with Pi-Wei-Xu-Ruo syndrome.In addition,the SSA/P size was linearly correlated with the related protein expression.CONCLUSION Patients with DCSR syndrome had a more obvious Wnt signaling pathway activation and a higher risk of carcinogenesis.A high-quality colonoscopic diagnosis was essential.The thorough assessment of clinical diseases can be improved by combining the diseases of Western medicine with the syndromes of traditional Chinese medicine.

Effects of curcumin on uterine leiomyoma in a rat model by inhibiting β-catenin/Wnt signaling pathway

Background:Women with uterine leiomyomas may suffer severe symptoms.To avoid risks of side effects,it is necessary to develop an optimal agent to shrink leiomyomas with fewer side effects and a lower recurrence rate.Curcumin may have a lower side effect in uterine leiomyoma treatment.Methods:We established the estrogen-and-progesterone-induced murine model of uterine leiomyoma.Next,we determined the expression of related genes of the β-catenin/Wnt signaling pathway by western blot,reverse transcription-polymerase chain reaction,and immunohistochemistry.We also noticed the morphological changes in uterine tissues by hematoxylin-eosin staining.Results:Curcumin plays an important role in Wnt/β-catenin signaling pathway-related expression including β-catenin,adenomatous polyposis coli,glycogen synthase kinase-3β,Wnt-11,and serum hormone concentrations.Conclusions:Curcumin could the down-regulation of serum hormone concentrations and inhibition of the β-catenin/Wnt signaling pathway in the treatment of uterine leiomyoma.

Loss of canonical Wnt signaling is involved in the pathogenesis of Alzheimer's disease

Alzheimer＇s disease（AD） is the most common form of dementia in the older population, however, the precise cause of the disease is unknown. The neuropathology is characterized by the presence of aggregates formed by amyloid-β（Aβ） peptide and phosphorylated tau; which is accompanied by progressive impairment of memory. Diverse signaling pathways are linked to AD, and among these the Wnt signaling pathway is becoming increasingly relevant, since it plays essential roles in the adult brain. Initially, Wnt signaling activation was proposed as a neuroprotective mechanism against Aβ toxicity. Later, it was reported that it participates in tau phosphorylation and processes of learning and memory. Interestingly, in the last years we demonstrated that Wnt signaling is fundamental in amyloid precursor protein（APP） processing and that Wnt dysfunction results in Aβ production and aggregation in vitro. Recent in vivo studies reported that loss of canonical Wnt signaling exacerbates amyloid deposition in a transgenic（Tg） mouse model of AD. Finally, we showed that inhibition of Wnt signaling in a Tg mouse previously at the appearance of AD signs, resulted in memory loss, tau phosphorylation and Aβ formation and aggregation; indicating that Wnt dysfunction accelerated the onset of AD. More importantly, Wnt signaling loss promoted cognitive impairment, tau phosphorylation and Aβ1–42 production in the hippocampus of wild-type（WT） mice, contributing to the development of an Alzheimer＇s-like neurophatology. Therefore, in this review we highlight the importance of Wnt/β-catenin signaling dysfunction in the onset of AD and propose that the loss of canonical Wnt signaling is a triggering factor of AD.

A growing field: the regulation of axonal regeneration by Wnt signaling

The canonical Wnt/β-catenin pathway is a highly conserved signaling cascade that plays critical roles during embryogenesis. Wnt ligands regulate axonal extension, growth cone guidance and synaptogenesis throughout the developing central nervous system （CNS）. Recently, studies in mammalian and fish model systems have demonstrated that Wnt/β-catenin signaling also promotes axonal regeneration in the adult optic nerve and spinal cord after injury, raising the possibility that Wnt could be developed as a therapeutic strategy. In this review, we summarize experimental evidence that reveals novel roles for Wnt signaling in the injured CNS, and discuss possible mechanisms by which Wnt ligands could overcome molecular barriers inhibiting axonal growth to promote regeneration. A central challenge in the neuroscience field is developing therapeutic strategies that induce robust axonal regeneration. Although adult axons have the capacity to respond to axonal guidance molecules after injury, there are several major obstacles for axonal growth, including extensive neuronal death, glial scars at the injury site, and lack of axonal guidance signals. Research in rodents demonstrated that activation of Wnt/β-catenin signaling in retinal neurons and radial glia induced neuronal survival and axonal growth, but that activation within reactive glia at the injury site promoted proliferation and glial scar formation. Studies in zebrafish spinal cord injury models confirm an axonal regenerative role for Wnt/β-catenin signaling and identified the cell types responsible. Additionally, in vitro and in vivo studies demonstrated that Wnt induces axonal and neurite growth through transcription-dependent effects of its central mediator β-catenin, potentially by inducing regeneration-promoting genes. Canonical Wnt signaling may also function through transcription-independent interactions of β-catenin with cytoskeletal elements, which could stabilize growing axons and control growth cone movement. Therefore, these studies suggest that Wnt-induced pathways responsible for regulating axonal growth during embryogenesis could be repurposed to promote axonal growth after injury.

Activation of canonical Wnt signaling pathway promotes proliferation and self-renewal of rat hepatic oval cell line WB-F344 in vitro

AIM： To investigate the effect of activation of canonical Wnt signaling pathway on the proliferation and differentiation of hepatic oval cells in vitro. METHODS： WB-F344 cells were treated with recombinant Wnt3a （20, 40, 80, 160, 200 ng/mL） in serum-free medium for 24 h. Cell proliferation was measured by Brdu incorporation analysis; untreated WB-F344 cells were taken as controls. After treatment with Wnt3a （160 ng/mL） for 24 h, subcellular localization and protein expression of p-catenin in WB-F344 cells treated and untreated with Wnt3a were examined by immunofluorescence staining and Western blot analysis. CyclinD1 mRNA expression was determined by semi-quantitative reverse-transcript polymerase chain reaction （RT-PCR）. The mRNA levels of some phenotypic markers （AFP, CK-19, ALB） and two hepatic nuclear factors （HNF-4, HIVF-6） were measured by RT-PCR. Expressions of CK-19 and AFP protein were detected by Western blot analysis. RESULTS： Wnt3a promoted proliferation of WB-F344 cells. Stimulation of WB-F344 cells with recombinant Wnt3a resulte^l in accumulation of the transcriptional activator β-catenin, together with its translocation into the nuclei, and up-regulated typical Wnt target gene CyclinD1. After 3 d of Wnt3a treatment in the absence of serum, WB-F344 cells retained their bipotential to express several specific phenotypic markers of hepatocytes and cholangiocytes, such as AFP and CK-19, following activation of the canonical Wnt signaling pathway. CONCLUSION： The canonical Wnt signaling pathway promotes proliferation and self-renewal of rat hepatic oval cells.

Mutations in components of the Wnt signaling pathway in gastric cancer

AIM: To explore the contribution of AXIN1, AXIN2 and beta-catenin, components of Wnt signaling pathway, to the carcinogenesis of gastric cancer (GC), we examined AXIN1, AXIN2 exon7 and CTNNB1 (encoding beta- catenin) exon3 mutations in 70 GCs. METHODS: The presence of mutations was identified by polymerase chain reaction (PCR)-based denaturing high-performance liquid chromatography and direct DNA sequencing. Beta-catenin expression was detected by immunohistochemical analysis. RESULTS: Among the 70 GCs, 5 (7.1%) had mutations in one or two of these three components. A frameshift mutation (1 bp deletion) in exon7 of AXIN2 was found in one case. Four cases, including the case with a mutation in AXIN2, had frameshift mutations and missense mutations in AXIN1. Five single nucleotide polymorphisms (SNPs), 334 C>T, 874 C>T, 1396 G>A, 1690 C>T and 1942 T>G, were identified in AXIN1. A frameshift mutation (27 bp deletion) spanning exon3 of CTNNB1 was observed in one case. All four cases with mutations in AXIN1 and AXIN2 showed nuclear beta- catenin expression. CONCLUSION: These data indicate that the mutationsin AXIN1 and AXIN2 may contribute to gastric carcino- genesis.

Down-regulation of mi R-30a-3p/5p promotes esophageal squamous cell carcinoma cell proliferation by activating the Wnt signaling pathway

AIM To investigate the potential role of micro RNA-30 a(mi R-30 a) in esophageal squamous cell carcinoma(ESCC).METHODS Expression of mi R-30 a-3 p/5 p was analyzed using microarray data and fresh ESCC tissue samples. Both in vitro and in vivo assays were used to investigate the effects of mi R-30 a-3 p/5 p on ESCC cell proliferation. Furthermore,Kyoto Encyclopedia of Genes and Genomes analysis was performed to explore underlying mechanisms involved in ESCC,and then,assays were carried out to verify the potential molecular mechanism of mi R-30 a in ESCC.RESULTS Low expression of mi R-30 a-3 p/5 p was closely associated with advanced ESCC progression and poor prognosis of patients with ESCC. Knock-down of mi R-30 a-3 p/5 p promoted ESCC cell proliferation. Increased mi R-30 a-3 p/5 p expression inhibited the Wnt signaling pathway by targeting Wnt2 and Fzd2.CONCLUSION Down-regulation of mi R-30 a-3 p/5 p promotes ESCC cell proliferation by activating the Wnt signaling pathway through inhibition of Wnt2 and Fzd2.

Differential involvement of Wnt signaling in Bmp regulation of cancellous versus periosteal bone growth

Bone morphogenetic proteins （Bmp） are well-known to induce bone formation following chondrogenesis, but the direct role of Bmp signaling in the osteoblast lineage is not completely understood. We have recently shown that deletion of the receptor Bmprla in the osteoblast lineage with Dmpl-Cre reduces osteoblast activity in general but stimulates proliferation of preosteoblasts specifically in the cancellous bone region, resulting in diminished periosteal bone growth juxtaposed with excessive cancellous bone formation. Because expression of sclerostin （SOST）, a secreted Wnt antagonist, is notably reduced in the Bmprla- deficient osteocytes, we have genetically tested the hypothesis that increased Wnt signaling might mediate the increase in cancellous bone formation in response to Bmprla deletion. Forced expression of human SOST from a Dmpl promoter fragment partially rescues preosteoblast hyperproliferation and cancellous bone overgrowth in the Bmprla mutant mice, demonstrating functional interaction between Bmp and Wnt signaling in the cancellous bone compat^a-tent. To test whether increased Wnt signaling can compensate for the defect in periosteal growth caused by Bmprla deletion, we have generated compound mutants harboring a hyperactive mutation （A214V） in the Wnt receptor Lrp5. However, the mutant Lrp5 does not restore periosteal bone growth in the Bmprla-deficient mice. Thus, Bmp signaling restricts cancellous bone accrual partly through induction of SOST that limits preosteoblast proliferation, but promotes periosteal bone growth apparently independently of Wnt activation.

Angiogenesis in a 3D model containing adipose tissue stem cells and endothelial cells is mediated by canonical Wnt signaling

Adipose-derived stromal cells （ASCs） have gained great attention in regenerative medicine. Progress in our understanding of adult neovascularization further suggests the potential of ASCs in promoting vascular regeneration, although the specific cues that stimulate their angiogenic behavior remain controversial In this study, we established a three-dimensional （3D） angiogenesis model by co-culturing ASCs and endothelial cells （ECs） in collagen gel and found that ASC-EC-instructed angiogenesis was regulated by the canonical Wnt pathway. Furthermore, the angiogenesis that occurred in implants collected after injections of our collagen gel- based 3D angiogenesis model into nude mice was confirmed to be functional and also regulated by the canonical Wnt pathway. Wnt regulation of angiogenesis involving changes in vessel length, vessel density, vessel sprout, and connection numbers occurred in our system. Wnt signaling was then shown to regulate ASC- mediated paracrine signaling during angiogenesis through the nuclear translocation of β-catenin after its cytoplasmic accumulation in both ASCs and ECs. This translocation enhanced the expression of nuclear cofactor Lef-1 and cyclin D1 and activated the angiogenic transcription of vascular endothelial growth factor A （VEGFA）, basic fibroblast growth factor （bFGF）, and insulin-like growth factor 1 （IGF-1）. The angiogenesis process in the 3D collagen model appeared to follow canonical Wnt signaling, and this model can help us understand the importance of the canonical Wnt pathway in the use of ASCs in vascular regeneration.

Two Natural ent-kauranoids as Novel Wnt Signaling Inhibitors

Constitutively active Wnt signaling frequently occurs in most colon cancers.Therefore,inhibitors of Wnt signaling pathway could provide rational therapeutic effects for colorectal malignancy.Within this paper,we identified two inhibitors of Wnt signaling pathway,rabdoternin B and maoecrystal I from a natural ent-kauranoid library by a dualluciferase reporter gene assay.The two compounds inhibited Wnt signaling pathway in a concentration-dependent manner and exhibited selective cytotoxicity toward a number of colon carcinoma cell lines SW480,HCT116,and HT29,with only weak cytotoxicity towards the normal colonic epithelial cell line CCD-841-CoN.Rabdoternin B and maoecrystal I treatment induced G2/M phase arrest efficiently in SW480 cells as revealed by flow cytometry analysis.A further study found that maoecrystal I decreased the expression of Wnt signaling target genes,including c-myc,cyclin D1,survivin and Axin2 in colon cancer cells.Collectively our data suggests that rabdoternin B and maoecrystal I are novel inhibitors of canonical Wnt signaling pathway and may possess potentials for colon cancer therapy.

Involvement of the Wnt signaling pathway and cell apoptosis in the rat hippocampus following cerebral ischemia/reperfusion injury

We investigated the role of the Wnt signaling pathway in cerebral ischemia/reperfusion injury by examining β-catenin and glycogen synthase kinase-3β protein expression in the rat hippocampal CA1 region following acute cerebral ischemia/reperfusion. Our results demonstrate that cell apoptosis increases in the CA1 region following ischemia/reperfusion. In addition, β-catenin and glycogen synthase kinase-3β protein expression gradually increases, peaking at 48 hours following reperfusion. Dickkopf-1 administration, after cerebral ischemia/reperfusion injury, results in decreased cell apoptosis, and β-catenin and glycogen synthase kinase-3β expression, in the CA1 region. This suggests that β-catenin and glycogen synthase kinase-3β, both components of the Wnt signaling pathway, participate in cell apoptosis following cerebral ischemia/reperfusion injury.

Alcohol-induced Wnt signaling inhibition during bone fracture healing is normalized by intermittent parathyroid hormone treatment

Nearly half of orthopaedic trauma patients are intoxicated at the time of injury, and excess alcohol consumption increases the risk for fracture nonunion. Previous studies show alcohol disrupts fracture associated Wnt signaling required for normal bone fracture repair. Intermittent parathyroid hormone(PTH) promotes bone growth through canonical Wnt signaling, however, no studies have investigated the effect of PTH on alcohol-inhibited bone fracture repair. Male C57 BL/6 mice received two-3 day alcohol binges separated by 4 days before receiving a mid-shaft tibia fracture. Postoperatively, mice received PTH daily until euthanasia. Wnt/β-catenin signaling was analyzed at 9 days post-fracture. As previously observed, acute alcohol exposure resulted in a >2-fold decrease in total and the active form of β-catenin and a 2-fold increase in inactive β-catenin within the fracture callus. Intermittent PTH abrogated the effect of alcohol on β-catenin within the fracture callus. Upstream of β-catenin, alcohol-treated animals had a 2-fold decrease in total LRP6, the Wnt co-receptor, which was restored with PTH treatment. Alcohol nor PTH had any significant effect on GSK-3β. These data show that intermittent PTH following a tibia fracture restores normal expression of Wnt signaling proteins within the fracture callus of alcohol-treated mice.

Suppression of AOM/DSS-induced colorectal cancer by scutellarin through downregulation of Wnt signaling pathway activity

OBJECTIVE To investigate the therapeutic effect of scutellarin on colitis-associated cancer(CAC)and its underlying mechanism based on Wnt/β-catenin signaling pathway.METHODS The mouse model of CAC was established by azomethane oxide(AOM)and sodium dextran sulfate(DSS),followed by scutellarin treatment,with recording the body weight,diarrhea and hematochezia.After sacrificing the mice,the colorectal length and colorectal tumor were assessed.The levels of pro-inflammatory factors TNF-αand IL-6 in mice′s sera were measured by the enzyme-linked immunosorbent assay(ELISA).The colorectal lesions were appraised by hematoxylin and eosin(H&E)staining.Theβ-catenin level in CAC tissues was probed by immunofluorescent analysis.The apoptosis-related genes Bax and Bcl-2,and Wnt signaling pathway-related genesβ-catenin,GSK-3β,TCF4,c-Myc and cyclin D1 were detected by real-time quantitative RT-PCR(RT-qPCR).Finally,Western blotting analysis(WB)was employed to examine the expressions of the apoptosis and Wnt signaling pathway-related proteins.RESULTS Scutellarin significantly improved AOM/DSS-caused weight loss,colorectal length shortening,and tumor growth in mice(P<0.01).Meanwhile,colorectal lesions could be substantially alleviated by scutellarin.ELISA results showed that the levels of pro-inflammatory factors TNF-αand IL-6 were drastically lessened(P<0.01).Scutellarin also sharply inhibited the nuclear translocation ofβ-catenin,as evidenced by the reduction in the nuclear level ofβ-catenin protein.In addition,scutellarin attenuated the mRNA expression of Wnt signaling pathway-relatedβ-catenin,TCF4,c-Myc and cyclin D1,whereas it heightened GSK-3βmRNA level.These results were consolidated by WB analysis,which indicated that scutellarin could mitigate the protein levels of phospho-GSK-3β,β-catenin,TCF4,c-Myc and cyclin D1,with the increase in GSK-3βprotein in CAC tissue.Moreover,scutellarin could induce the apoptosis of CAC,demonstrated by enhanced expression of Bax and diminished expression of Bcl-2 in both mRNA and protein levels.CONCLUSION Scutellarin may ameliorate colitis-associated colorectal cancer by weakening Wnt/β-catenin signaling cascade.

A reporter gene system for screening inhibitors of Wnt signaling pathway

Abnormal activation of canonical Wnt signaling has been associated with various types of cancer.Inhibitory reagents targeting the Wnt signaling have great potential to inhibit the growth of relevant tumors.Here we generated a cell-based screening strategy for identification of antagonists of the Wnt/β-catenin signaling pathway.Stable expression wnt3a was generated in HEK293 cell line,which harbors dual-luciferase reporters.The Wnt signaling in the stably transfected cell line was proved to be very sensitive to(-)-epigallocatechin-3-gallate(EGCG)and lithium chloride(LiCl)treatment,respectively.Natural compounds were screened and a couple of novel inhibitory modulators of the Wnt signaling pathway were obtained.

The Effect of Frat-1, Idax and Axam toward the Wnt Signaling Pathway

This paper describes the effect of Frat-1, Idax and Axam toward the Wnt signaling pathway. The Wnt pathway is an important intracellular signaling pathway that plays a crucial role in the cell cycle process at several levels of development. Understanding this pathway thoroughly will enable identification of new drug targets and thereby open avenues to more effective therapies for a range of Wnt pathway related diseases such as cancer, osteoporosis, and mesothelioma. Dishevelled （Dsh） is one of the multi-module proteins working m the Wnt pathway. The function of Dsh depends on the regulators which bind to it, components it interacts with and most importantly the Wnt signal. It is important to note that positive regulators are those factors that induce gene transcription. Conversely, the negative regulators induce β-Catenin degradation. The positive regulator such as Frat- 1 would promote the Wnt signaling pathway and downstream gene transcription. Meanwhile the negative regulator such as Idax and Axam would inhibit the signaling pathway and promotes β-Catenin degradation which will thereby prevent aberrant gene transcription.

Cycloartane Glycosides from the Roots of Cimicifuga foetida with Wnt Signaling Pathway Inhibitory Activity

Four new 9,19-cycloartane triterpenoids,cimilactone E(1),cimilactone F(2),20-O-(E)-butenoyl-23-epi-26-deoxyactein(3),and 20,12b-O-diacetylcimiracemonol-3-O-b-D-xylopyranoside(4),together with four known constituents(5–8)were isolated from the roots of Cimicifuga foetida.The new structures were elucidated by extensive spectroscopic analysis.In addition,compounds 7 and 8 showed significant Wnt signaling pathway inhibitory activity,with IC50 values of 3.33 and 13.34 lM,respectively,using the luciferase reporter gene assay.

Ursolic acid ameliorates azoxymethane/dextran sulfate sodium-caused colorectal cancer by inhibition of Wnt signaling cascade

OBJECTIVE To investigate the pharmacological effect of ursolic acid(UA)on colitis-associated colorectal cancer(CAC)and its underlying mechanism based on the Wnt signaling pathway.METHODS The CAC model in mice was established by azoxymethane(AOM)combined and dextran sulfate sodium salt(DSS),accompanied by treatment with various dosages of UA and concomitant appraisal of body weight,stool and physical state of the mice.After the sacrifice of the mice,the tumor and length of the colorectum were measured,followed by retrieval of the liver,spleen,thymus and tumor tissue for downstream assays.The levels of inflammatory factors interleukin-6(IL-6),IL^(-1)βand C-reactive protein(CRP)in the tumor and serum were examined by enzyme-linked immunosorbent assay(ELISA).The pathological changes of colorectal tissues were observed by HE staining.The levels in tumors of Wnt/β-catenin signaling pathway-related proteins Wnt4,GSK-3β,β-catenin,TCF4,LEF1,c-Myc,cyclin D1 and apoptosis-related protein Bcl-2 were assayed by immunohistochemistry(IHC).The mRNA expressions of Wnt4,GSK-3β,β-catenin,TCF4,LEF1,c-Myc,cyclin D1,Bcl-2,Bax,caspase-9 and caspase-3 in tumors were detected by real-time quantitative RT-PCR(RT-qPCR).The protein levels of Wnt4,GSK-3β,β-catenin,TCF4,LEF1,c-Myc,cyclin D1,phospho-β-catenin,phospho-GSK-3β,Bcl-2 and Bax in tumors were probed by analyzed by Western blotting(WB).Also,RNA-seq was employed to assess the gut microbiota in the mice.RESULTS UA significantly ameliorated the symptoms of AOM/DSS-induced mouse CAC,evidenced by improved physical state,body weight,survival rate,colorectal length,the mass of liver,thymus,spleen,and decreased CAC load and colorectal mass.UA attenuated the levels of IL-6,IL^(-1)βand CRP in the mouse serum and colorectal tumor in a dose-dependent manner.HE staining showed that UA lessened carcinogenesis in the colorectum,with lower infiltration of lymphocytes,versus the control.IHC indicated that UA mitigated the expression of Wnt4,β-catenin,TCF4,LEF1,c-Myc,cyclin D1,Bcl-2,and promoted the GSK-3βexpression,compared with the control.Furthermore,UA diminished the mRNA expressions of Wnt4,β-catenin,TCF4,LEF1,c-Myc,cyclin D1,Bcl-2,and heightened the mRNA levels of GSK-3β,caspase-3,capase-9 and Bax in CAC.The results of mRNA expressions were verified by WB analysis,which revealed that UA impeded the protein expression of Wnt4,β-catenin,c-Myc,cyclin D1,Bcl-2,TCF4,LEF1,and elevated the protein levels of GSK-3βand Bax,phospho-β-catenin in mouse CAC.In addition,UA substantially ameliorated the gut microbiota to store the metabolic function in the mice with CAC.CONCLUSION Ursolic acid may protect against CAC,potentially by downregulation of Wnt/β-catenin signaling pathway activity and restoration of gut microbiota.

CYP24A1 Involvement in Inflammatory Factor Regulation Occurs via the Wnt Signaling Pathway

Objective While the upregulation of cytochrome P450 family 24 subfamily A member 1(CYP24A1)gene expression has been reported in colon cancer,its role in tumorigenesis remains largely unknown.In this study,we aimed to investigate the involvement of CYP24A1 in Wnt pathway regulation via the nuclear factor kappa B(NF-κB)pathway.Methods The human colon cancer cell lines HCT-116 and Caco-2 were subjected to stimulation with interleukin-6(IL-6)as well as tumor necrosis factor alpha(TNF-α),with subsequent treatment using the NF-κB pathway-specific inhibitor ammonium pyrrolidinedithiocarbamate(PDTC).Furthermore,CYP24A1 expression was subjected to knockdown via the use of small interfering RNA(siRNA).Subsequently,NF-κB pathway activation was determined by an electrophoretic mobility shift assay,and the transcriptional activity ofβ-catenin was determined by a dual-luciferase reporter assay.A mouse ulcerative colitis(UC)-associated carcinogenesis model was established,wherein TNF-αand the NF-κB pathway were blocked by anti-TNF-αmonoclonal antibody and NF-κB antisense oligonucleotides,respectively.Then the tumor size and protein level of CYP24A1 were determined.Results IL-6 and TNF-αupregulated CYP24A1 expression and activated the NF-κB pathway in colon cancer cells.PDTC significantly inhibited this increase in CYP24A1 expression.Additionally,knockdown of CYP24A1 expression by siRNA could partially antagonize Wnt pathway activation.Upregulated CYP24A1 expression was observed in the colonic epithelial cells of UC-associated carcinoma mouse models.Anti-TNF-αmonoclonal antibody and NF-κB antisense oligonucleotides decreased the tumor size and suppressed CYP24A1 expression.Conclusion Taken together,this study suggests that inflammatory factors may increase CYP24A1 expression via NF-κB pathway activation,which in turn stimulates Wnt signaling.

Suppressing Wnt signaling of the blood-tumor barrier to intensify drug delivery and inhibit lipogenesis of brain metastases

Lipogenesis is often highly upregulated in breast cancer brain metastases to adapt to intracranial low lipid microenvironments.Lipase inhibitors hold therapeutic potential but their intra-tumoral distribution is often blocked by the blood-tumor barrier(BTB).BTB activates its Wnt signaling to maintain barrier properties,e.g.,Mfsd2a-mediated BTB low transcytosis.Here,we reported VCAM-1-targeting nano-wogonin(W@V-NPs)as an adjuvant of nano-orlistat(O@V-NPs)to intensify drug delivery and inhibit lipogenesis of brain metastases.W@V-NPs were proven to be able to inactivate BTB Wnt signaling,downregulate BTB Mfsd2a,accelerate BTB vesicular transport,and enhance tumor accumulation of O@V-NPs.With the ability to specifically kill cancer cells in a lipid-deprived environment with IC_(50) at 48 ng/mL,W@V-NPs plus O@V-NPs inhibited the progression of brain metastases with prolonged survival of model mice.The combination did not induce brain edema,cognitive impairment,and systemic toxicity in healthy mice.Targeting Wnt signaling could safely modulate the BTB to improve drug delivery and metabolic therapy against brain metastases.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in develop-ment and adult tissue homeostasis across species.Wnt proteins are secreted,lipid-modified signaling molecules that activate the canonical(β-catenin dependent)and non-canonical(β-catenin independent)Wnt signaling pathways.Cellular behaviors such as proliferation,differ-entiation,maturation,and proper body-axis specification are carried out by the canonical pathway,which is the best characterized of the known Wnt signaling paths.Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues.This includes but is not limited to embryonic,hematopoietic,mesenchymal,gut,neural,and epidermal stem cells.Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties.Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders.Not surprisingly,aberrant Wnt signaling is also associated with a wide variety of diseases,including cancer.Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation,epithelial-mesenchymal transition,and metastasis.Altogether,advances in the understand-ing of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway.Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt,this review aims to summarize the cur-rent knowledge of Wnt signaling in stem cells,aberrations to the Wnt pathway associated with diseases,and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.