Bardet-Biedl syndrome (BBS) is a pleiotropic ciliopathy caused by dysfunction of the BBSome, a cargo adaptor essential for export of transmembrane receptors from cilia. Although actin-dependent ectocytosis has been proposed to compensate defective cargo retrieval, its molecular basis remains unclear, especially in relation to BBS pathology. In this study, we investigated how actin polymerization and ectocytosis are regulated within the cilium. Our findings reveal that ciliary CDC42, a RHO-family GTPase triggers in situ actin polymerization, ciliary ectocytosis, and cilia shortening in BBSome-deficient cells. Activation of the Sonic Hedgehog pathway further enhances CDC42 activity specifically in BBSome-deficient cilia. Inhibition of CDC42 in BBSome-deficient cells decreases the frequency and duration of ciliary actin polymerization events, causing buildup of G protein coupled receptor 161 (GPR161) in bulges along the axoneme during Sonic Hedgehog signaling. Overall, our study identifies CDC42 as a key trigger of ciliary ectocytosis. Hyperactive ciliary CDC42 and ectocytosis and the resulting loss of ciliary material might contribute to BBS disease severity.

• Klíčová slova
• Actin, Bardet-Biedl Syndrome, CDC42, Cilium, Ectocytosis,
• MeSH
• aktiny * metabolismus   MeSH
• Bardetův-Biedlův syndrom * metabolismus   genetika   patologie   MeSH
• cdc42 protein vázající GTP * metabolismus   genetika   MeSH
• cilie * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• proteiny hedgehog metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   genetika   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aktiny * MeSH
• cdc42 protein vázající GTP * MeSH
• proteiny hedgehog MeSH
• receptory spřažené s G-proteiny MeSH

Breast cancer is the most prevalent cancer type in women worldwide. It proliferates rapidly and can metastasize into farther tissues at any stage due to the gradual invasiveness and motility of the tumor cells. These crucial properties are the outcome of the weakened intercellular adhesion, regulated by small guanosine triphosphatases (GTPases), which hydrolyze to the guanosine diphosphate (GDP)-bound conformation. We investigated the inactivating effect of ARHGAP1 on Rho GTPases involved signaling pathways after treatment with a high dose of doxorubicin. Label-free quantitative proteomic analysis of the proteome isolated from the MCF-7 breast cancer cell line, treated with 1 μM of doxorubicin, identified RAC1, CDC42, and RHOA GTPases that were inactivated by the ARHGAP1 protein. Upregulation of the GTPases involved in the transforming growth factor-beta (TGF-beta) signaling pathway initiated epithelial-mesenchymal transitions. These findings demonstrate a key role of the ARHGAP1 protein in the disruption of the cell adhesion and simultaneously allow for a better understanding of the molecular mechanism of the reduced cell adhesion leading to the subsequent metastasis. The conclusions of this study corroborate the hypothesis that chemotherapy with doxorubicin may increase the risk of metastases in drug-resistant breast cancer cells.

• Klíčová slova
• breast cancer, cell adhesion, doxorubicin, mass spectrometry, metastases, proteomics,
• MeSH
• cdc42 protein vázající GTP metabolismus   MeSH
• doxorubicin farmakologie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• nádory prsu * farmakoterapie   MeSH
• proteiny aktivující GTPasu * metabolismus   MeSH
• proteomika MeSH
• rac1 protein vázající GTP metabolismus   MeSH
• Rho proteiny vázající GTP * metabolismus   MeSH
• rhoA protein vázající GTP metabolismus   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ARHGAP1 protein, human MeSH Prohlížeč
• cdc42 protein vázající GTP MeSH
• doxorubicin MeSH
• proteiny aktivující GTPasu * MeSH
• rac1 protein vázající GTP MeSH
• Rho proteiny vázající GTP * MeSH
• rhoA protein vázající GTP MeSH

Benzimidazole anthelmintics flubendazole and mebendazole are microtubule-targeting drugs that showed considerable anti-cancer activity in different preclinical models. In this study, the effects of flubendazole and mebendazole on proliferation, migration and cadherin switching were studied in a panel of oral cell lines in vitro. Both compounds reduced the viability of the PE/CA-PJ15 and H376 oral squamous carcinoma cells and of the premalignant oral keratinocytes DOK with the IC50 values in the range of 0.19-0.26 μM. Normal oral keratinocytes and normal gingival fibroblasts were less sensitive to the treatment. Flubendazole and mebendazole also reduced the migration of the PE/CA-PJ15 cell in concentrations that had no anti-migratory effects on the normal gingival fibroblasts. Levels of the focal adhesion kinase FAK, Rho-A and Rac1 GTPases and the Rho guanine nucleotide exchange factor GEF-H1 were decreased in both PE/CA-PJ15 cells and gingival fibroblasts following treatment. Both drugs also interfered with cadherin switching in the model of TGF-β-induced epithelial to mesenchymal transition (EMT) in the DOK cell line. Levels of N-cadherin were reduced in the TGF-β induced cells co-treated with flubendazol and mebendazole in very low concentration (50 nM). These results suggest direct effects of both benzimidazoles on selected processes of EMT in oral cell lines such as cadherin switching as well as cellular migration.

• Klíčová slova
• Benzimidazoles, Cadherin switching, EMT, Gingival fibroblasts, Oral squamous carcinoma cells,
• MeSH
• buněčné linie MeSH
• cdc42 protein vázající GTP metabolismus   MeSH
• epitelo-mezenchymální tranzice účinky léků   MeSH
• fokální adhezní kinasa 1 metabolismus   MeSH
• kadheriny metabolismus   MeSH
• lidé MeSH
• mebendazol analogy a deriváty   farmakologie   MeSH
• nádory úst metabolismus   patologie   MeSH
• pohyb buněk účinky léků   MeSH
• proliferace buněk účinky léků   MeSH
• rhoA protein vázající GTP metabolismus   MeSH
• spinocelulární karcinom metabolismus   patologie   MeSH
• transformující růstový faktor beta farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cdc42 protein vázající GTP MeSH
• flubendazole MeSH Prohlížeč
• fokální adhezní kinasa 1 MeSH
• kadheriny MeSH
• mebendazol MeSH
• rhoA protein vázající GTP MeSH
• transformující růstový faktor beta MeSH