LncRNA HOTAIR regulates anoikis-resistance capacity and spheroid formation of ovarian cancer cells by recruiting EZH2 and influencing H3K27 methylation

Abstract

This study aims to investigate the role of the long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) in the regulation of anoikis resistance of ovarian cancer c ells, a prerequisite for metastasis and chemoresistance in ovarian cancer cells. Ova rian cancer SKOV3 cells were cultured in an ultra-low attachment system to establish an anoikis model. The relationship between cellular anoikis capability and HOTAIR expression level was studied by flow cytometry and RT-PCR. The ability of spheroid formation, migration, and invasion of the suspended cells was assessed following the knockdown of HOTAIR expression. The expression of EZH2, H3K27me3, representative targets of EZH2, and anoikis-related biomarkers was also detected. An increase in the duration of suspension culture time rendered the SKOV3 cells anoikis-resistant with a significantly lower apoptotic rate compared to the adherent cells. HOTAIR expression in the suspension cells increased significantly, while that in the adherent cells did not. Following small interfering RNA (siRNA)-mediated knockdown of HOTAIR expression, the abilities of anoikis resistance, migration, and invasion decreased in the suspension cells. Knockdown of HOTAIR levels also reduced the spheroid forming ability of the tumor c ells in continuous suspension cultures. Moreover, EZH2 expression correlated with HOTAIR expression, thus regulating the expression of miR-193a and DOK2 via introducing H3K27me3. Western blot analysis of anoikis-related markers showed that N-cadherin, ZEB1, and TWIST1 were downregulated following inhibition of HOTAIR, while E-cadherin and ErbB3 were upregulated. In conclusion, HOTAIR enhances the anoikis resistance and spheroid forming ability of ovarian cancer cells by recruiting EZH2 and influencing H3K27 methylation that may contribute to migration, invasion, and chemoresistance of ovarian cancer cells.

Association between long non‑coding RNA HOTAIR polymorphism and lung cancer risk: A systematic review and meta‑analysis

“…(54). Furthermore, HOTAIR also interacts with several classic signaling pathways, which are commonly involved in oncogenesis, such as CCL22 signaling (55), the Wnt/β-catenin signaling pathway (56), EZH2 and H3K27 methylation signaling (57). All of this evidence, as well as that provided by the present meta-analysis, suggests the importance of lncRNA HOTAIR SNP in the development of lung cancer.…”

Downregulation of cell division cycle-associated protein 7 (CDCA7) suppresses cell proliferation, arrests cell cycle of ovarian cancer, and restrains angiogenesis by modulating enhancer of zeste homolog 2 (EZH2) expression

“…As an important component of polycomb group proteins (PcGs), EZH2 has been confirmed to be overexpressed in a variety of cancer types with lethal outcomes, including OC cases [ 13 , 14 ]. The EZH2 gene mainly contributes to tumor development by promoting angiogenesis, silencing tumor suppressor genes and inhibiting the apoptosis of tumor cells [ 22 , 23 ].…”

“…Moreover, EZH2 is responsible for trimethylation of histone H3 on Lys27 (H3K27me3) that results in epigenetic gene silencing. Recent research indicates that EZH2 is overexpressed in various tumor tissues and closely related to tumor infiltration, metastasis and prognosis [ 13 , 14 ]. Accordingly, inhibition of EZH2 might be a promising strategy for therapies of cancers in the future.…”

Long noncoding RNA ASH1L-AS1 promotes glycolysis and cisplatin resistance in ovarian cancer cells via its regulation on EZH2-mediated CNRIP1 methylation

“…However, the researches focused on the speci c function of ASH1L-AS1 in the progression of OC are rare, which aroused our great interest in exploring something deeper in this topic. Moreover, enhancer of zester homolog 2 (EZH2) is well-known as a histone methyl transferase could regulate polycomb repressive complex 2 (PRC2) to mediate the trimethylating the lysine 27 residue of histone H3 (H3K27me3), the overexpression of which has been implicated in the tumor growth and chemoresistance in OC [13,14]. A previous study demonstrated that the methylation of cannabinoid receptor interacting protein 1 (CNRIP1) promoter is involved in the regulation of the activity for cancerous cells [15,16], which was identi ed as a downstream gene of ASH1L-AS1 in our earlier investigation using bioinformatic analysis.…”