title: AMPK activators suppress cervical cancer cell growth through inhibition of DVL3 mediated Wnt/β-catenin signaling activity.
abstract: Recent evidence has suggested that AMPK activators may be applied as therapeutic drugs in suppressing cancer cell growth. However, the molecular mechanism of their suppressive function in cancer cells is still unclear. Here we show that AMPK activators impair cervical cancer cell growth through the reduction of DVL3, a positive regulator in Wnt/β-catenin signaling and an oncogenic player in cervical cancer tumorigenesis. By western blot and immunohistochemical analyses, we demonstrated that DVL3 was frequently upregulated and significantly associated with elevated β-catenin (P = 0.009) and CyclinD1 (P = 0.009) expressions in cervical cancer. Enforced expression of DVL3 elevated β-catenin and augmented cervical cancer cell growth, verifying that DVL3-mediated Wnt/β-catenin activation is involved in cervical cancer oncogenesis. On the other aspect, we noted that the cervical cancer cell growth was remarkably suppressed by AMPK activators and such cell growth inhibition was in concomitant with the reduction of DVL3 protein level in dose- and time-dependent manners. Besides, impaired mTOR signaling activity also reduced DVL3 expression. In contrast, co-treatment with Compound C (AMPK inhibitor) could significantly abrogate metformin induced DVL3 reduction. In addition, co-treatment with AM114 or MG132 (proteosomal inhibitors) could partially restore DVL3 expression under the treatment of metformin. Further in vivo ubiquitination assay revealed that metformin could reduce DVL3 by ubiquitin/proteasomal degradation. To our knowledge, this is the first report showing the probable molecular mechanisms of that the AMPK activators suppress cervical cancer cell growth by impairing DVL3 protein synthesis via AMPK/mTOR signaling and/or partially promoting the proteasomal degradation of DVL3.
authors.affiliation: Department of Obstetrics and Gynaecology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: H T
authors.initials: HT
authors.lastname: Kwan
authors.forename: David W
authors.initials: DW
authors.lastname: Chan
authors.forename: Patty C H
authors.initials: PC
authors.lastname: Cai
authors.forename: Celia S L
authors.initials: CS
authors.lastname: Mak
authors.forename: Mingo M H
authors.initials: MM
authors.lastname: Yung
authors.forename: Thomas H Y
authors.initials: TH
authors.lastname: Leung
authors.forename: Oscar G W
authors.initials: OG
authors.lastname: Wong
authors.forename: Annie N Y
authors.initials: AN
authors.lastname: Cheung
authors.forename: Hextan Y S
authors.initials: HY
authors.lastname: Ngan
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000072261:Dishevelled Proteins; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D005260:Female; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D010750:Phosphoproteins / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000201:enzymology* / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C000606584:DVL3 protein, human; D000072261:Dishevelled Proteins; D010750:Phosphoproteins; D051153:Wnt Proteins; D051176:beta Catenin; D055372:AMP-Activated Protein Kinases