The regulation of protein translation and its implications for cancer

ELK4-mediated lncRNA SNHG22 promotes gastric cancer progression through interacting with EZH2 and regulating miR-200c-3p/Notch1 axis

Long non-coding RNAs (lncRNAs) play important regulatory roles in the initiation and progression of various cancers. However, the biological roles and the potential mechanisms of lncRNAs in gastric cancers remain unclear. Here, we report that the expression of lncRNA SNHG22 (small nucleolar RNA host gene 22) was significantly increased in GC (Gastric Cancer) tissues and cells, which confers poor prognosis of patients. Knockdown of SNHG22 inhibited the proliferation and invasion ability of GC cells. Moreover, we identified that the transcriptional factor, ELK4 (ETS transcription factor ELK4), could promote SNHG22 expression in GC cells. In addition, using RNA pull-down followed MS assay, we found that SNHG22 directly bound to EZH2 (enhancer of zeste 2 polycomb repressive complex 2 subunit) to suppress the expression of tumor suppressor genes. At the same time, SNHG22 sponged miR-200c-3p to increase Notch1 (notch receptor 1) expression. Taken together, our findings demonstrated the role of SNHG22 on promoting proliferation and invasion of GC cells. And we revealed a new regulatory mechanism of SNHG22 in GC cells. SNHG22 is a promising lncRNA biomarker for diagnosis and prognosis and a potential target for GC treatment.

Identification of an N6-methyladenosine (m6A)-related signature associated with clinical prognosis, immune response, and chemotherapy in primary glioblastomas

Background

N6-methyladenosine (m6A) RNA methylation regulators play crucial role in tumorigenicity and progression. However, their biological significance in primary glioblastomas (GBM) has not been fully elucidated.

Methods

In the present study, we evaluated the 22 m6A RNA regulators using the integrated data of primary GBM samples from The Cancer Genome Atlas and Chinese Glioma Genome Atlas databases. The different m6A modification patterns and m6A-related gene signature in primary GBM were distinguished by using principal component analysis. Single-sample gene set enrichment analysis was introduced to assess the relative level of immune infiltration. Gene set variation analysis was performed to calculate the enrichment score of the signaling pathways for different clusters. An m6A scoring scheme was established to evaluate the m6A modification pattern in individual tumors in order to predict prognosis and evaluate tumor microenvironment (TME) cell infiltration, immune response, and chemotherapy effect in primary GBM.

Results

Two distinct m6A modification subgroups associated with different clinical features and biological pathways were identified among the 371 primary GBM. Based on 132 prognostic m6A phenotype-related differentially expressed genes (DEGs) between 2 m6A cluster subgroups, an m6A scoring model was constructed to assess the m6A modification pattern in individual tumors. The high-m6A score group was associated with better prognosis and immune response and worse chemotherapy effect.

Conclusions

The findings of the present study indicate the potential role of m6A modification in primary GBM, which will help enhance our understanding of TME characteristics, predict clinical prognosis, and provide important insight into effective immunotherapy and chemotherapy.

Identification of a robust signature for clinical outcomes and immunotherapy response in gastric cancer: based on N6-methyladenosine related long noncoding RNAs

BACKGROUND

Gastric cancer (GC) is a globally prevalent cancer, ranking fifth for incidence and fourth for mortality worldwide. The N6-methyladenosine (m6A) related long noncoding RNAs (lncRNAs) were widely investigated in recent studies. Nevertheless, the underlying prognostic implication and tumor immune mechanism of m6A-related lncRNA in GC remain unknown.

METHODS

We systematically assessed the m6A modification expression of 407 GC clinical samples based on 23 m6A regulators and comprehensively associated these genes with lncRNAs. Then, we constructed a m6A-related lncRNA prognostic signature (m6A-LPS) to evaluate both status and prognosis of the disease. Immune-related mechanisms were explored via dissecting tumor-infiltrating cells as well as applying tumor immune dysfunction and the exclusion algorithm. Furthermore, we validated the latent regulative mechanism of m6A-related lncRNA in GC cell lines.

RESULTS

The m6A-LPS containing nine hub lncRNAs was built, which possessed a superior capability to predict the outcomes of GC patients. Meanwhile, we found an intimate correlation between the m6A-LPS and tumor infiltrating cells, and that the low-risk group had a higher expression of immune checkpoints and responsed more to immunotherapy than the high-risk group. Clinically, these crucial lncRNAs expression levels were verified in ten pairs of GC samples. In in vitro experiments, the abilities of migration and proliferation were significantly enhanced via downregulating the lncRNA AC026691.1. Both migrative and proliferative capabilities of tumor cells were significantly enhanced via downregulating the lncRNA AC026691.1. in vitro.

CONCLUSIONS

Collectively, the m6A-LPS could provide a novel prediction insight into the prognosis of GC patients and serve as an independent clinical factor for GC. These m6A-related lncRNAs might remodel the tumor microenvironment and affect the anti-cancer ability of immune checkpoint blockers. Importantly, lncRNA AC026691.1 could inhibit both migration and proliferation of GC by means of FTO regulation.

The Biological Function, Mechanism, and Clinical Significance of m6A RNA Modifications in Head and Neck Carcinoma: A Systematic Review

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers, yet the molecular mechanisms underlying its onset and development have not yet been fully elucidated. Indeed, an in-depth understanding of the potential molecular mechanisms underlying HNSCC oncogenesis may aid the development of better treatment strategies. Recent epigenetic studies have revealed that the m6A RNA modification plays important roles in HNSCC. In this review, we summarize the role of m6A modification in various types of HNSCC, including thyroid, nasopharyngeal, hypopharyngeal squamous cell, and oral carcinoma. In addition, we discuss the regulatory roles of m6A in immune cells within the tumor microenvironment, as well as the potential molecular mechanisms. Finally, we review the development of potential targets for treating cancer based on the regulatory functions of m6A, with an aim to improving targeted therapies for HNSCC. Together, this review highlights the important roles that m6A modification plays in RNA synthesis, transport, and translation, and demonstrates that the regulation of m6A-related proteins can indirectly affect mRNA and ncRNA function, thus providing a novel strategy for reengineering intrinsic cell activity and developing simpler interventions to treat HNSCC.