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- Mehic, Merima, Sr., et al.
(author)
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The role of deubiquitinating enzyme USP17, hyaluronan synthase 2, and hyaluronan in non-small-cell lung cancer oncogenic transformation
- 2018
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In: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 24:1, s. 96-96
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Journal article (other academic/artistic)abstract
- Introduction: Lung cancer is the result of a multistep accumulation of genetic and/or epigenetic alterations; therefore, a better understanding of the molecular mechanism by which these alterations affect lung cancer pathogenesis would provide new diagnostic procedures and prognostic factors for early detection of recurrence. The remarkable qualitative and quantitative modifications of extracellular matrix components as the deubiquitinating enzyme (USP17), hyaluronan (HA), and hyaluronan synthases 2 (HAS 2) may favor invasion, cellular motility, and proliferation in several cancers including lung.Results: The silencing of USP17 led to decreased hyaluronan production, whereas the suppression of USP4 increased hyaluronan synthesis. Importantly, high levels of USP17 and HAS2 were detected in a panel of cancer cell lines compared to normal cells, and immunohistochemical stainings revealed higher expression of USP17 and HAS2 in tissues of lung cancer patients compared to normal tissue. Numerous epithelial cells expressed USP17 and HAS2 in dysplasia compared to squamous cell carcinoma (SqCC) (p=0.001). USP17 and HAS2 were prominently expressed in adenocarcinoma (ADC) (p≤0.005). HA immunostaining indexes were increased in ADC and SqCC compared to normal and dysplasia cells (p=0.05). Consistent with the immunohistochemical analyses, low amounts of hyaluronan and USP17 were observed in SqCC by confocal analysis, coincident with less colocalization as determined by confocal microscopy. In contrast, a high expression of hyaluronan (48% of positive index) and high USP17 expression (78% of positive index) in ADC was consistent with a higher degree of colocalization.Conclusions: HAS2, hyaluronan and USP17 were expressed at higher levels in particular in preneoplastic lesions and ADC, suggesting a role in NSCLC oncogenic transformation, possibly by promoting cellular division by USP17-mediated. Elucidation of the mechanism of how USP17 and HAS2 cooperate in the regulation of the cell cycle might be of therapeutic importance.
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| 2. |
- Mehić, Merima, et al.
(author)
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The deubiquitinating enzymes USP4 and USP17 target hyaluronan synthase 2 and differentially affect its function
- 2017
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In: Oncogenesis. - : Springer Science and Business Media LLC. - 2157-9024. ; 6
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Journal article (peer-reviewed)abstract
- The levels of hyaluronan, a ubiquitous glycosaminoglycan prominent in the extracellular matrix, is balanced through the actions of hyaluronan-synthesizing enzymes (HAS1, 2 and 3) and degrading hyaluronidases (Hyal 1, 2, 3 and PH20). Hyaluronan accumulates in rapidly remodeling tissues, such as breast cancer, due to deregulated expression of the HAS2 gene and/or alterations of HAS2 activity. The activity of HAS2 is regulated by post-translational modifications, including ubiquitination. In order to identify deubiquitinating enzymes (DUBs) that are involved in de-ubiquitination of HAS2, a complementary (cDNA) library of 69 Flag-HA-tagged human DUBs cloned into retroviral vectors was screened in human embryonic kidney (HEK) 293T cells for their ability to de-ubiquitinate myc-tagged HAS2. Several DUBs were found to decrease the ubiquitination of 6myc-HAS2, among which, the most effective were USP17 and USP4. USP17 efficiently removed polyubiquitination, whereas USP4 preferentially removed monoubiquitination of 6myc-HAS2. Co-immunoprecipitation studies revealed interactions between HAS2 and USP17, as well as between HAS2 and USP4, in membrane preparations of HEK293T cells. USP17 significantly stabilized 6myc-HAS2 protein levels, whereas USP4 did not. The silencing of USP17 led to decreased hyaluronan production, whereas the suppression of USP4 increased hyaluronan synthesis. Importantly, high levels of USP17 and HAS2 were detected in a panel of cancer cell lines compared to normal cells, and immunohistochemical stainings revealed higher expression of USP17 and HAS2 in tissues of lung cancer patients compared to normal tissue. In conclusion, USP17 and USP4 differently affect HAS2 ubiquitination, and the stability and function of HAS2.
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