| Type 2 diabetes(T2DM)and cancer have become two major public health worldwide.The possible association between diabetes and cancer risk has long been speculated.Most studies have reported increased risk of total cancer among patients with diabetes.Compared to cancer patients without type 2 diabetes,those with type 2 diabetes have poor prognosis and increased mortality.These results indicate that type 2 diabetes promotes tumorigenesis and development.Studies have shown that centrosome amplification can transform non-tumor cells into tumor cells and form tumors in animals.Mice with centrosome amplification is sufficient to promote spontaneous tumorigenesis.Centrosome amplification can also increase the invasiveness of tumor cells.In most human cancers,centrosome amplification has been associated with high-grade tumors and poor prognosis.These observations indicate that centrosome amplification can initiate tumorigenesis and promote cancer progression.At specific stages of disease development,patients with type 2 diabetes exhibit pathophysiological features such as hyperglycemia,hyperinsulinemia,elevated levels of free fatty acids in plasma and elevated levels of advanced glycation end products(AGEs).Based on these pathophysiology factors,we recently discovered that high glucose,insulin and palmitic acid can promote centrosome amplification through ROCK1/ 14-3-3?,PPAR?-SKA1 and PCNA-ROCK1 pathway,and inhibit centrosome amplification through the JNK1-Stat3-14-3-3? pathway.Also,AGEs can cause centrosome amplification through the transcription factor KLF5.In the present study,we further investigated the molecular mechanisms underlying type 2 diabetesassociated centrosome amplification.Results:1.Treatment of HCT116 cells with high glucose,insulin and palmitic acid increased the intracellular and the extracellular protein levels of Wnt6.The Wnt6 si RNA or FZD4 si RNA effectively inhibited the treatment-increased centrosome amplification in the HCT116 cells.Anti-Wnt6 and anti-FZD4 antibody was able to attenuate the treatment-increased centrosome amplification in a dose-dependent manner in the HCT116,when introduced into the cell culture medium.It is known that ?-catenin is the downstream signal mediator of Wnt6/FZD4 in the canonical Wnt signaling pathway.Thus,we investigated whether ?-catenin mediated the centrosome amplification.We found that high glucose,insulin and palmitic acid elicited ?-catenin translocation.?-catenin si RNA was also able to inhibit the treatment-evoked centrosome amplification.Finally,we investigated whether Wnt6/FZD4 mediates high glucose,insulin,and palmitate induce centrosome amplification through ?-catenin,and found that Wnt6 or FZD4 si RNA favored the distribution of ?-catenin to the cytoplasm and blocked the treatment-elicited translocation of ?-catenin to the nuclear,and knockdown of ?-catenin did not alter the expressions of Wnt6 and FZD4.2.In HCT116 cells treated with high glucose,insulin and palmitic acid,Wnt6/FZD4/?-catenin signaling pathway was upstream of ROCK1 and 14-3-3?.In colon tissues from diabetic mice model,the protein levels of Wnt6 and 14-3-3? were increased.3.AGEs were able to trigger cell centrosome amplification in a dosedependent manner in HCT116 and IEC-6 cells.In the HCT116 cells,AGEs increased the intracellular and extracellular levels of Wnt6 protein,Both Wnt6 and FZD4 si RNAs were able to inhibit the AGEs-evoked centrosome amplification.Interestingly,antibody against Wnt6 or FZD4 also attenuated the AGEs-increased centrosome amplification in a dose-dependent manner,when introduced into the cell cultures.Moreover,AGEs also triggered nuclear translocation of ?-catenin.?-catenin si RNA inhibited the AGEs-induced centrosome amplification.Wnt6 and FZD4 specific si RNA could affect ?-catenin nuclear localization,but ?-catenin si RNAs did not alter Wnt6 and FZD4 expression.Conclusion: Pathophysiological factors in diabetes,including AGEs,can induce centrosome amplification through the signaling of canonical Wnt6 signaling pathway. |
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