A-to-I edited miR-411-5p targets MET and promotes TKI response in NSCLC-resistant cells

Writers, readers, and erasers RNA modifications and drug resistance in cancer

Drug resistance in cancer cells significantly diminishes treatment efficacy, leading to recurrence and metastasis. A critical factor contributing to this resistance is the epigenetic alteration of gene expression via RNA modifications, such as N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), 7-methylguanosine (m7G), pseudouridine (Ψ), and adenosine-to-inosine (A-to-I) editing. These modifications are pivotal in regulating RNA splicing, translation, transport, degradation, and stability. Governed by "writers," "readers," and "erasers," RNA modifications impact numerous biological processes and cancer progression, including cell proliferation, stemness, autophagy, invasion, and apoptosis. Aberrant RNA modifications can lead to drug resistance and adverse outcomes in various cancers. Thus, targeting RNA modification regulators offers a promising strategy for overcoming drug resistance and enhancing treatment efficacy. This review consolidates recent research on the role of prevalent RNA modifications in cancer drug resistance, with a focus on m6A, m1A, m5C, m7G, Ψ, and A-to-I editing. Additionally, it examines the regulatory mechanisms of RNA modifications linked to drug resistance in cancer and underscores the existing limitations in this field.

miR-199a-5p targets DUSP14 to regulate cell proliferation, invasion and stemness in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) shows the highest morbidity among malignant tumors worldwide. Despite improvements of diagnosis and treatment, patient prognosis remains unfavorable. Therefore, there is a need to discover a novel treatment strategy for NSCLC. DUSP14 is related to various cancers as the regulatory factor for cellular processes. However, its specific roles in NSCLC and the upstream modulator remain largely unclear.

Methods

DUSP14 expression patterns within the lung cancer patient cohort from TCGA database were analyzed using UALCAN online tool. Different databases including miRDB, starbase, and Targetscan were employed to screen the upstream regulator of DUSP14. DUSP14 and miR-199a-5p expression was determined by qRT-PCR and Western blot techniques. To confirm binding interaction of DUSP14 with miR-199a-5p, we conducted a dual-luciferase reporter assay. Cell viability, migration, and stemness properties were assessed using CCK-8, EdU (5-ethynyl-2'-deoxyuridine) incorporation, transwell invasion, and sphere formation assays. The effect of DUSP14 silencing on tumorigenesis was assessed with the NSCLC cell xenograft mouse model.

Results

Our study discovered that DUSP14 exhibited high expression within NSCLC tumor samples, which is related to the dismal prognostic outcome in NSCLC patients. Silencing DUSP14 impaired NSCLC cell proliferation, migration, and tumor sphere formation. Besides, we identified miR-199a-5p as the upstream regulatory factor for DUSP14, and its expression was negatively related to DUSP14 level within NSCLC tissues. Introducing miR-199a-5p recapitulated the function of DUSP14 silencing in NSCLC cell aggressiveness and stemness. Moreover, knocking down DUSP14 efficiently inhibited tumor formation in NSCLC cells of the xenograft model.

Conclusions

Our study suggests that DUSP14 is negatively regulated by miR-199a-5p within NSCLC, whose overexpression is required for sustaining NSCLC cell proliferation, invasion and stemness.

RNA editing enzymes: structure, biological functions and applications

With the advancement of sequencing technologies and bioinformatics, over than 170 different RNA modifications have been identified. However, only a few of these modifications can lead to base pair changes, which are called RNA editing. RNA editing is a ubiquitous modification in mammalian transcriptomes and is an important co/posttranscriptional modification that plays a crucial role in various cellular processes. There are two main types of RNA editing events: adenosine to inosine (A-to-I) editing, catalyzed by ADARs on double-stranded RNA or ADATs on tRNA, and cytosine to uridine (C-to-U) editing catalyzed by APOBECs. This article provides an overview of the structure, function, and applications of RNA editing enzymes. We discuss the structural characteristics of three RNA editing enzyme families and their catalytic mechanisms in RNA editing. We also explain the biological role of RNA editing, particularly in innate immunity, cancer biogenesis, and antiviral activity. Additionally, this article describes RNA editing tools for manipulating RNA to correct disease-causing mutations, as well as the potential applications of RNA editing enzymes in the field of biotechnology and therapy.

The novel miR-873-5p-YWHAE-PI3K/AKT axis is involved in non-small cell lung cancer progression and chemoresistance by mediating autophagy

Non-small cell lung cancer (NSCLC) encompasses approximately 85% of all lung cancer cases and is the foremost cancer type worldwide; it is prevalent in both sexes and known for its high fatality rate. Expanding scientific inquiry underscores the indispensability of microRNAs in NSCLC. Here, we probed the impact of miR-873-5p on NSCLC development and chemoresistance. qRT‒PCR was used to measure the miR-873-5p level in NSCLC cells with or without chemoresistance. A model of miR-873-5p overexpression was constructed. The proliferation and viability of NSCLC cells were evaluated through CCK8 and colony formation experiments. Cell migration and invasion were monitored via Transwell assays. Western blotting was used to determine the levels of YWHAE, PI3K, AKT, EMT, apoptosis, and autophagy-related proteins. The sensitivity of NSCLC cells to the chemotherapeutic agent gefitinib was assessed. Additionally, the correlation of YWHAE with miR-873-5p was validated via a dual-luciferase reporter assay and RNA immunoprecipitation (RIP). Overexpressed miR-873-5p suppressed migration, proliferation, invasion, and EMT while concurrently stimulating apoptotic processes. miR-873-5p was downregulated in NSCLC cells resistant to gefitinib. Upregulating miR-873-5p reversed gefitinib resistance by inducing autophagy. YWHAE was confirmed to be a downstream target of miR-873-5p. YWHAE overexpression promoted the malignant behaviors of NSCLC cells and boosted tumor growth, while these effects were reversed following miR-873-5p overexpression. Subsequent investigations revealed that overexpressing YWHAE promoted PI3K/AKT pathway activation, with miR-873-5p displaying inhibitory effects on the YWHAE-mediated PI3K/AKT signaling cascade. miR-873-5p affects proliferation, invasion, migration, EMT, autophagy, and chemoresistance in NSCLC by controlling the YWHAE/PI3K/AKT axis.