ABSTRACT
Long non-coding RNAs (lncRNAs) are emerging as regulators in cancer development and progression, and aberrant lncRNA profiles have been reported in several cancers. Here, we evaluated the potential of using the maternally expressed gene 3 (MEG3) tissue level as a prognostic marker in high-grade serous ovarian cancer (HGSOC), the most common and deadliest gynecologic malignancy. To the aim of the study, we measured MEG3 transcript levels in 90 pre-treatment peritoneal biopsies. We also investigated MEG3 function in ovarian cancer biology. We found that high MEG3 expression was independently associated with better progression-free (p = 0.002) and overall survival (p = 0.01). In vitro and in vivo preclinical studies supported a role for MEG3 as a tumor suppressor in HGSOC, possibly through modulation of the phosphatase and tensin homologue (PTEN) network. Overall, results from this study demonstrated that decreased MEG3 is a hallmark for malignancy and tumor progression in HGSOC.
ABSTRACT
BACKGROUND: In this study we investigated the function of the non-catalytic region of tyrosine kinase adaptor protein 2 (NCK2) and its correlation with ITGB1 and ITGB4 integrins in driving ovarian cancer (OvCa) aggressiveness. We also evaluated whether NCK2 may influence prognosis in OvCa patients. METHODS: Nanofluidic technology was used to analyze expression of NCK2 in 332 OvCa patients. To evaluate mRNA expression of NCK2, integrins and VEGFA in OvCa cell lines, qRT-PCR was performed. Stable NCK2 overexpression was obtained in OVCAR3. qRT-PCR and Western blot were performed to evaluate expression changes of VEGFA, vimentin, ITGB1, ITGB4, MMP2 and MMP9 under normoxia and hypoxia conditions. Coimmunoprecipitation (Co-IP) was performed in the A2780 cell line to study the interaction between NCK2 and proteins of interest. To investigate whether NCK2 can influence anchorage-independent growth, a soft agar assay was completed. Transwell invasion assay was performed on stable-transfected OVCAR-3 cell lines. RESULTS: Nanofluidic data showed NCK2 can play an important role as a factor promoting tumor aggressiveness and survival in OvCa. This role was also linked to the behaviors of ITGB1 and ITGB4. Moreover, in cells overexpressing NCK2, the expression of vimentin, MMP2, MMP9, VEGFA and ITGB1, but not of ITGB4 was induced by hypoxia. Co-IP showed that NCK2 can directly bind ITGB1, but not VEGFA. NCK2 may be involved in mediating cell-extracellular matrix interactions in OvCa cells by influencing tumor aggressiveness. CONCLUSIONS: This study provides evidence of a possible role of NCK2 as biomarker of OvCa progression.