MiR-17- 5p/RRM2 regulated gemcitabine resistance in lung cancer A549 cells

Significance of Ribonucleoside-diphosphate Reductase Subunit M2 in Lung Adenocarcinoma

INTRODUCTION

The Ribonucleoside-diphosphate Reductase subunit M2 (RRM2) is known to be overexpressed in various cancers, though its specific functional implications remain unclear. This aims to elucidate the role of RRM2 in the progression of Lung Adenocarcinoma (LUAD) by exploring its involvement and potential impact.

METHODS

RRM2 data were sourced from multiple databases to assess its diagnostic and prognostic significance in LUAD. We evaluated the association between RRM2 expression and immune cell infiltration, analyzed its function, and explored the effects of modulating RRM2 expression on LUAD cell characteristics through laboratory experiments.

RESULTS

RRM2 was significantly upregulated in LUAD tissues and cells compared to normal counterparts (p < 0.05), with rare genetic alterations noted (approximately 2%). This overexpression clearly distinguished LUAD from normal tissue (area under the curve (AUC): 0.963, 95% confidence intervals (CI): 0.946-0.981). Elevated RRM2 expression was significantly associated with adverse clinicopathological characteristics and poor prognosis in LUAD patients. Furthermore, a positive association was observed between RRM2 expression and immune cell infiltration. Pathway analysis revealed a critical connection between RRM2 and the cell cycle signaling pathway within LUAD. Targeting RRM2 inhibition effectively suppressed LUAD cell proliferation, migration, and invasion while promoting apoptosis. This intervention also modified the expression of several crucial proteins, including the downregulation of CDC25A, CDC25C, RAD1, Bcl-2, and PPM1D and the upregulation of TP53 and Bax (p < 0.05).

CONCLUSION

Our findings highlight the potential utility of RRM2 expression as a biomarker for diagnosing and predicting prognosis in LUAD, shedding new light on the role of RRM2 in this malignancy.

Integrative analysis of gene and microRNA expression profiles reveals candidate biomarkers and regulatory networks in psoriasis

Psoriasis (PS) is a chronic inflammatory skin disease with a long course and tendency to recur, the pathogenesis of which is not fully understood. This article aims to identify the key differentially expressed genes (DEGs) and microRNA (miRNAs) of PS, construct the core miRNA-mRNA regulatory network, and investigate the underlying molecular mechanism through integrated bioinformatics approaches. Two gene expression profile datasets and 2 miRNA expression profile datasets were downloaded from the gene expression omnibus (GEO) database and analyzed by GEO2R. Intersection DEGs and intersection differentially expressed miRNAs (DEMs) were each screened. The Metascape database and R software were used to perform enrichment analysis of intersecting DEGs and study their functions. Target genes of DEMs were predicted from the online database miRNet. The protein-protein interaction files of the overlapping target genes were obtained from string and the miRNA-mRNA network was constructed by Cytoscape software. In addition, the online web tool CIBERSORT was used to analyze the immune infiltration of dataset GSE166388, and the relative abundance of 22 immune cells in the diseased and normal control tissues was calculated and assessed. Finally, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the relative expression of the screened miRNAs and mRNAs to assess the applicability of DEMs and DEGs as biomarkers in PS. A total of 205 mating DEGs and 6 mating DEMs were screened. 103 dysregulated crossover genes from 205 crossover DEGs and 7878 miRNA target genes were identified. The miRNA-mRNA regulatory network was constructed and the top 10 elements were obtained from CytoHubba, including hsa-miR-146a-5p, hsa-miR-17-5p, hsa-miR-106a-5p, hsa-miR-18a-5p, CDK1, CCNA2, CCNB1, MAD2L1, RRM2, and CCNB2. QRT-PCR revealed significant differences in miRNA and gene expression between inflammatory and normal states. In this study, the miRNA-mRNA core regulator pairs hsa-miR-146a-5p, hsa-miR-17-5p, hsa-miR-106a-5p, hsa-miR-18a-5p, CDK1, CCNA2, CCNB1, MAD2L1, RRM2, and CCNB2 may be involved in the course of PS. This study provides new insights to discover new potential targets and biomarkers to further investigate the molecular mechanism of PS.

Exosomal microRNAs in lung cancer: a narrative review

Background and Objective

Exosomes are nanoscale extracellular vesicles secreted by cells, which can release bioactive macromolecules, such as microRNA (miRNA) to receptor cells. Exosomes can efficiently penetrate various biological barriers which mediate intercellular communication. MiRNA are a class of non-coding RNA that primarily regulate messenger RNA (mRNA) at the post-transcriptional level. MiRNA is abundant in exosomes, which plays an important role by being transported and released through exosomes secreted by lung cancer cells. This review aims to elucidate the roles of exosome-derived miRNAs in lung cancer.

Methods

We focused on the roles of exosome-derived miRNAs in cancer occurrence and development, including angiogenesis, cell proliferation, invasion, metastasis, immune escape, drug resistance, and their clinical value as new diagnostic and prognostic markers for lung cancer.

Key Content and Findings

Exosomal miRNA can not only affect angiogenesis of lung cancer, induce epithelial-mesenchymal transformation, and promote reprogramming of tumor microenvironment, but also affect immune regulation and drug resistance transmission and participate in regulating lung cancer cell proliferation. Therefore, understanding the regulatory roles of exosomal miRNAs in tumor invasion and metastasis can provide new ideas for the treatment of lung cancer.

Conclusions

Exosomal miRNA can provide some unique ideas on how to improve the efficiency of diagnosis and treatment of lung cancer in the future. Targeting tumor-specific exosomal miRNA represents a new strategy for clinical treatment of lung cancer, which can provide potential non-invasive biomarkers in the early diagnosis of lung cancer. Investigation of the involvement of exosomal miRNAs in the occurrence and progression of tumors can yield new opportunities for the clinical diagnosis and treatment of lung cancer.

MBD3 promotes epithelial-mesenchymal transition in gastric cancer cells by upregulating ACTG1 via the PI3K/AKT pathway

BACKGROUND

Gastric cancer (GC) is a common malignancy and a leading cause of cancer-related death with high morbidity and mortality. Methyl-CpG binding domain protein 3 (MBD3), a key epigenetic regulator, is abnormally expressed in several cancers, participating in progression and metastasis. However, the role of MBD3 in GC remains unknown.

METHODS

MBD3 expression was assessed via public databases and validated by western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). The prognosis of MBD3 was analysed via bioinformatics based on the TCGA dataset. The migration, invasion and proliferation of GC cells were examined by transwell, wound healing, cell counting kit (CCK)-8, colony-formation and xenograft mouse models. Epithelial-mesenchymal transition (EMT) and phosphatidylinositide 3-kinases/ protein Kinase B (PI3K/AKT) pathway markers were evaluated by Western blotting. RNA sequencing was used to identify the target of MBD3.

RESULTS

MBD3 expression was higher in GC tissues and cells than in normal tissues and cells. Additionally, high MBD3 levels were associated with poor prognosis in GC patients. Subsequently, we proved that MBD3 enhanced the migration, invasion and proliferation abilities of GC cells. Moreover, western blot results showed that MBD3 promoted EMT and activated the PI3K/AKT pathway. RNA sequencing analysis showed that MBD3 may increase actin γ1 (ACTG1) expression to promote migration and proliferation in GC cells.

CONCLUSION

MBD3 promoted migration, invasion, proliferation and EMT by upregulating ACTG1 via PI3K/AKT signaling activation in GC cells and may be a potential diagnostic and prognostic target.

β-elemene enhances cisplatin sensitivity of non-small cell lung cancer cells via the miR-17-5p/STAT3 axis

In China, β-elemene, a sesquiterpene compound derived from Curcuma wenyujin, is clinically used to treat many human malignancies, including non-small cell lung cancer (NSCLC). Nonetheless, the role of β-elemene in regulating cisplatin sensitivity of NSCLC cells and the related mechanisms are not clear. This study was conducted to investigate the role of β-elemene in sensitizing NSCLC cells to cisplatin. In this work, cisplatin-resistant NSCLC cell lines were constructed. CCK-8, colony formation, and flow cytometry assays were executed to examine cell viability, growth, and apoptosis. MiR-17-5p and STAT3 expression levels in cells were detected by qRT-PCR. Western blot was executed to determine the expression levels of STAT3 and apoptosis-related proteins (Bax and Bcl-2) in the cells. Dual-luciferase reporter gene experiments were performed to verify the targeting relationship between miR-17-5p and STAT3. Herein, we report that, β-elemene inhibits the viability, and induces the apoptosis of cisplatin-resistant NSCLC cells. Additionally, β-elemene induces the upregulation miR-17-5p and downregulation of STAT3. STAT3 is validated to be a target of miR-17-5p in NSCLC cells. Additionally, the role of β-elemene to repress the viability of cisplatin-resistant NSCLC cells is partially counteracted by miR-17-5p inhibitor or STAT3 overexpression. In summary, our study suggests that β-elemene enhances cisplatin sensitivity of NSCLC cells by modulating miR-17-5p/STAT3 axis, and it may be a choice for the complementary treatment of NSCLC patients.

Advances in the role of microRNAs associated with the PI3K/AKT signaling pathway in lung cancer

Cancer has long been a topic of great interest in society and a major factor affecting human health. Breast, prostate, lung, and colorectal cancers are the top four tumor types with the greatest incidence rates in 2020, according to the most recent data on global cancer incidence. Among these, lung cancer had the highest fatality rate. Extensive research has shown that microRNAs, through different signaling pathways, play crucial roles in cancer development. It is considered that the PI3K/AKT signaling pathway plays a significant role in the development of lung cancer. MicroRNAs can act as a tumor suppressor or an oncogene by altering the expression of important proteins in this pathway, such as PTEN and AKT. In order to improve the clinical translational benefit of microRNAs in lung cancer research, we have generalized and summarized the way of action of microRNAs linked with the PI3/AKT signaling pathway in this review through literature search and data analysis.

p21 promotes gemcitabine tolerance in A549 cells by inhibiting DNA damage and altering the cell cycle

Gemcitabine is one of the most widely used chemotherapy drugs for advanced malignant tumors, including non-small cell lung cancer. However, the clinical efficacy of gemcitabine is limited due to drug resistance. The aim of the present study was to investigate the role of p21 in gemcitabine-resistant A549 (A549/G+) lung cancer cells. IC50 values were determined using a Cell Counting Kit-8 (CCK-8) assay. mRNA and protein expression levels of genes were measured by reverse transcription-quantitative PCR and western blotting, respectively. The cell cycle distribution and apoptosis rate were analyzed by flow cytometry. DNA damage in cells was evaluated by single-cell gel electrophoresis. The results of western blot analysis and the CCK-8 assay demonstrated that the expression of p21 was higher in A549/G+ cells than in gemcitabine-sensitive cells. Knockdown of p21 expression in gemcitabine-resistant cells sensitized these cells to gemcitabine (with the IC50 decreasing from 84.2 to 26.7 µM). Cell cycle analysis revealed different changes in the cell cycle distribution in A549/G+ cells treated with the same concentration of gemcitabine, and decreased expression of p21 was shown to promote G1 arrest. The apoptosis assay and comet assay results revealed that decreased p21 expression resulted in accumulation of unrepaired DNA double-strand breaks (DSBs) and induction of apoptosis by gemcitabine. The present study demonstrated that knockout of p21 mRNA expression in A549/G+ cells promotes apoptosis and DNA DSB accumulation, accompanied by G1 arrest. These results indicated that p21 is involved in regulating the response of A549 cells to gemcitabine.

RRM2‑mediated Wnt/β‑catenin signaling pathway activation in lung adenocarcinoma: A potential prognostic biomarker

The present study aimed to investigate the role and mechanism of action of ribonucleotide reductase M2 (RRM2) in lung adenocarcinoma and its potential as a therapeutic target. Data of patients with lung adenocarcinoma from The Cancer Genome Atlas database were collected and analyzed to evaluate the potential of RRM2 as a biomarker. The expression of RRM2 was evaluated in the A549 cell line and its cisplatin-resistant A549/DDP cell line derivative by western blot and reverse transcription-quantitative PCR. The study also investigated cell proliferation and the mechanism by which RRM2 controls cellular cisplatin resistance using CCK-8 and colony-formation assays. In addition, cell migration was assessed using Transwell assays, and the cell cycle and apoptosis were examined using flow cytometry. RRM2 was highly expressed in lung adenocarcinoma and was associated with the clinical TMN stage. Functional enrichment analysis showed that RRM2 was enriched in the cell cycle. Immune cell infiltration analysis identified 12 types of immune cell that exhibited differences between patients expressing different levels of RRM2. Cellular assays revealed higher levels of RRM2 expression in A549/DDP cells than A549 cells, and its expression was induced by cisplatin. RRM2 knockdown decreased cell proliferation and migration, accelerated apoptosis and caused cell cycle arrest in the S-phase, increasing the sensitivity of A549 and A549/DDP cells to cisplatin through the Wnt/β-catenin signaling pathway. Overexpression of β-catenin reduced the effects of RRM2 knockdown on A549 cells. Lung adenocarcinoma growth may be influenced by RRM2 through the Wnt/β-catenin signaling pathway, suggesting a potential pathway for cancer progression.