Long non-coding RNA TTN-AS1/microRNA-199a-3p/runt-related transcription factor 1 gene axis regulates the progression of oral squamous cell carcinoma

RUNX transcription factors: biological functions and implications in cancer

Runt-related transcription factors (RUNX) are a family of transcription factors that are essential for normal and malignant hematopoietic processes. Their most widely recognized role in malignancy is to promote the occurrence and development of acute myeloid leukemia. However, it is worth noting that during the last decade, studies of RUNX proteins in solid tumors have made considerable progress, suggesting that these proteins are directly involved in different stages of tumor development, including tumor initiation, progression, and invasion. RUNX proteins also play a role in tumor angiogenesis, the maintenance of tumor cell stemness, and resistance to antitumor drugs. These findings have led to the consideration of RUNX as a tumor biomarker. All RUNX proteins are involved in the occurrence and development of solid tumors, but the role of each RUNX protein in different tumors and the major signaling pathways involved are complicated by tumor heterogeneity and the interacting tumor microenvironment. Understanding how the dysregulation of RUNX in tumors affects normal biological processes is important to elucidate the molecular mechanisms by which RUNX affects malignant tumors.

Prognostic significance of long noncoding RNA TTN-AS1 in various malignancies

BACKGROUND

Increasing evidence has demonstrated that high TTN-AS1 expression is highly related to poor prognosis in diverse human cancers. However, the findings concerning the prognostic value of TTN-AS1 were inconsistent, as these conclusions were usually drawn with relatively small sample sizes. Hence, this meta-analysis proposes to investigate the prognostic significance of TTN-AS1 in multiple malignancies systematically.

METHODS

Web of Science, Springer, Embase, PubMed, Cochrane Library, and Scopus databases were comprehensively searched to retrieve studies related to the TTN-AS1 expression with the prognosis of malignancies. The significance of the TTN-AS1 in cancers was estimated by hazard ratios (HRs) or odds ratios (ORs). Additionally, the Gene Expression Profiling Interactive Analysis (GEPIA) analysis tool was used to strengthen our results further.

RESULTS

Twenty studies involving 17 different cancers and 1330 patients were recruited into this meta-analysis. The research revealed that high TTN-AS1 expression was remarkably associated with unfavorable overall survival (OS) (HR = 2.07, 95%CI [1.78, 2.41], p < .00001) when compared with low TTN-AS1 expression in malignancies. Additionally, elevated TTN-AS1 expression significantly contributed to lymph node metastasis (OR = 4.09, 95%CI [3.08, 5.44], p < .0001), larger tumor size (OR = 2.42, 95%CI [1.56, 3.77], p < .0001), worse tumor differentiation (OR = 0.36, 95%CI [0.22, 0.59], p < .0001) and more advanced tumor stage (OR = 0.29, 95%CI [0.22, 0.38], p < .0001) with low or no heterogeneity existing. Moreover, high TTN-AS1 expression  was connected with worse disease-free survival in five different cancers based on the GEPIA online database.

CONCLUSIONS

The results of this meta-analysis support that high TTN-AS1 expression significantly correlates with worse prognosis in various cancers. Therefore, TTN-AS1 may be considered as a novel biomarker for malignancies.

Long non-coding RNA PSMG3 Antisense RNA 1 is correlated with oral squamous cell carcinoma and regulates cancer cell proliferation by targeting premature microRNA-141

Oral squamous cell carcinoma (OSCC) is common worldwide. In this study, the interaction of microRNA-141 (miR-141) with long non-coding RNA (lncRNA) PSMG3 Antisense RNA 1 (PSMG3-AS1) in OSCC was explored. RT-qPCR was used to analyze the expression of PSMG3-AS1 and miR-141 (both mature and premature) in OSCC. Nuclear fractionation assay was applied to detect PSMG3-AS1 in subcellular locations. RNA pull-down assay was performed to evaluate the binding of miR-141 to PSMG3-AS1. Overexpression assay followed by RT-qPCR was performed to explore the role of PSMG3-AS1 in maturation of miR-141. The function of PSMG3-AS1 and miR-141 in regulating OSCC cell proliferation was assessed by BrdU assay. The results showed that PSMG3-AS1 was highly upregulated in OSCC and miR-141 was downregulated in OSCC. However, no alteration in the expression of premature miR-141 was observed in OSCC. Premature miR-141 was found to directly bind to PSMG3-AS1. Overexpression of PSMG3-AS1 suppressed the maturation of miR-141. PSMG3-AS1 increased OSCC cell proliferation and tumor growth and suppressed the inhibitory role of miR-141 in cell proliferation and tumor growth. Therefore, PSMG3-AS1 may inhibit the maturation of miR-141 to promote OSCC cell proliferation.

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.

Long non-coding RNA LINC00472 inhibits oral squamous cell carcinoma via miR-4311/GNG7 axis

Emerging studies indicate that long non-coding RNAs play important roles in oral squamous cell carcinoma (OSCC). However, the function of the majority of long non-coding RNAs is still unclear. Recently, LINC00472 has been reported to play crucial roles in multiple cancers. However, the role of LINC00472 in oral squamous cell carcinoma (OSCC) is still not clear. This study found that LncRNA LINC00472 was significantly down-regulated in several squamous cell carcinoma cancer tissues and OSCC cell lines. Over-expression of LINC00472 in OSCC cells inhibited OSCC progression and alleviated OSCC immune responses. Additionally, we confirmed that LINC00472 functioned as an hsa-miR-4311 sponge and regulated the expression of GNG7 (guanine nucleotide-binding protein, gamma 7). Also, we found that LINC00472 over-expression could suppress xenograft tumor growth in vivo. Our study provides evidence that LINC00472 plays an essential role in inhibiting oral squamous cell carcinoma progression and affecting immune responses by directly binding to hsa-miR-4311 to regulate the expression of GNG7 positively.