Long non-coding RNA LINC01296 acts as a migration and invasion promoter in head and neck squamous cell carcinoma and predicts poor prognosis

Yin Yang 1-Induced Long Noncoding RNA DUXAP9 Drives the Progression of Oral Squamous Cell Carcinoma by Blocking CDK1-Mediated EZH2 Degradation

LncRNAs play a critical role in oral squamous cell carcinoma (OSCC) progression. However, the function and detailed molecular mechanism of most lncRNAs in OSCC are not fully understood. Here, a novel nuclear-localized lncRNA, DUXAP9 (DUXAP9), that is highly expressed in OSCC is identified. A high level of DUXAP9 is positively associated with lymph node metastasis, poor pathological differentiation, advanced clinical stage, worse overall survival, and worse disease-specific survival in OSCC patients. Overexpression of DUXAP9 significantly promotes OSCC cell proliferation, migration, invasion, and xenograft tumor growth and metastasis, and upregulates N-cadherin, Vimentin, Ki67, PCNA, and EZH2 expression and downregulates E-cadherin in vitro and in vivo, whereas knockdown of DUXAP9 remarkably suppresses OSCC cell proliferation, migration, invasion, and xenograft tumor growth in vitro and in vivo in an EZH2-dependent manner. Yin Yang 1 (YY1) is found to activate the transcriptional expression of DUXAP9 in OSCC. Furthermore, DUXAP9 physically interacts with EZH2 and inhibits EZH2 degradation via the suppression of EZH2 phosphorylation, thereby blocking EZH2 translocation from the nucleus to the cytoplasm. Thus, DUXAP9 can serve as a promising target for OSCC therapy.

SIAH1/CTR9 axis promotes the epithelial-mesenchymal transition of hepatocellular carcinoma

SIAH1 has been reported to participate in several human cancers, including hepatocellular carcinoma (HCC). However, the effect of SIAH1 on the epithelial-mesenchymal transition (EMT) has not been reported in HCC cells. Here, we discovered the inhibitory effect of SIAH1 on HCC cell migration and invasion, which was related with regulating EMT. Molecularly, a yeast two-hybrid experiment indicated that Cln Three Requiring 9 (CTR9) was a potential interacting protein of SIAH1, which was further verified by co-immunoprecipitation assays. Furthermore, SIAH1 inhibited the EMT of HCC cells through negatively regulating CTR9. Importantly, CTR9 was ubiquitinated and degraded by SIAH1 via the proteasome pathway in HCC cells. Additionally, it was showed that SIAH1 mainly mediated the K48-linked polyubiquitination on CTR9. Finally, the protein level of CTR9 was found to be inversely correlated with SIAH1 in human HCC tissues. Summed up all together, these findings reveal that SIAH1/CTR9 axis promotes the EMT of HCC cells and is a promising therapeutic target for HCC therapy.

LINC01296 promotes cancer stemness traits in oral carcinomas by sponging miR-143

Background/purpose

Emerging evidence has shown that various failures in cancer therapy, such as drug resistance, metastasis, and cancer relapse are attributed to cancer stem cells (CSCs). Also, growing attention has been paid to the regulation of non-coding RNAs in cancer stemness. Here, we aimed to investigate the contribution of LINC01296 in the modulation of oral CSCs.

Materials and methods

The phenotypic assays including migration, invasion, and colony-forming abilities were carried out in CSCs of two types of oral cancer cells (SAS and GNM) following the knockdown of LINC01296. In addition, the percentage of cells expressing stemness marker, ALDH1, and drug resistance marker, ABCG2, was examined as well as the self-renewal capacity after silencing of LINC01296. Moreover, a luciferase reporter was used to validate the direct interaction between LINC01296 and miR-143.

Results

Our results showed that LINC01296 was significantly overexpressed in oral cancer tissues and positively correlated with stemness markers. The phenotypic and flow cytometry assays demonstrated that suppression of LINC01296 reduced the aggressiveness, cancer stemness features, and colony-forming and self-renewal abilities in oral CSCs. Furthermore, we demonstrated that LINC01296 may enhance cancer stemness features through suppression of the effect of miR-143.

Conclusion

Silencing of LINC01296 may be a promising direction for oral cancer therapy by reducing cancer stemness via regulation of miR-143.

Long non-coding RNA human leucocyte antigen complex group-18 HCG18 (HCG18) promoted cell proliferation and migration in head and neck squamous cell carcinoma through cyclin D1-WNT pathway

Emerging evidence has demonstrated that long noncoding RNA (lncRNAs) play a vital role in the development of head and neck squamous cell carcinoma (HNSCC); however, the biological effects and underlying mechanisms of human leukocyte antigen complex group-18 HCG18 (HCG18) have not yet been reported in HNSCC. In this study, we detected the expression of the HCG18 in HNSCC cell lines and patient tissues. We observed that HCG18 was upregulated in HNSCC patient tissues and cell lines. Furthermore, silencing of HCG18 significantly inhibited proliferation, migration, and invasion of HNSCC cells, whereas the opposite effects were detected in the HCG18-overexpressed group. We also found that HCG18 directly binds to the functional protein cyclin D1. Upregulated cyclin D1 reversed the inhibitory effects of HCG18 in HNSCC cell lines and activated the WNT pathway-related proteins (AXIN2, survivin, c-Myc, and β-catenin) simultaneously. Knockdown of cyclin D1 could accelerate the inhibitory effects of HCG18 and decrease the expression of AXIN2, survivin, c-Myc, and β-catenin. This indicated that lncRNA HCG18 might be involved in the tumorigenesis of HNSCC via the cyclin D1-WNT pathway. These results suggest that lncRNA HCG18 could act as a promising prognostic biomarker and potential therapeutic target in HNSCC patients.