MicroRNA-212 suppresses nonsmall lung cancer invasion and migration by regulating ubiquitin-specific protease-9

Cellular functions, molecular signalings and therapeutic applications: Translational potential of deubiquitylating enzyme USP9X as a drug target in cancer treatment

Protein ubiquitination, one of the most significant post-translational modifications, plays an important role in controlling the proteins activity in diverse cellular processes. The reversible process of protein ubiquitination, known as deubiquitination, has emerged as a critical mechanism for maintaining cellular homeostasis. The deubiquitinases (DUBs), which participate in deubiquitination process are increasingly recognized as potential candidates for drug discovery. Among these DUBs, ubiquitin-specific protease 9× (USP9X), a highly conserved member of the USP family, exhibits versatile functions in various cellular processes, including the regulation of cell cycle, protein endocytosis, apoptosis, cell polarity, immunological microenvironment, and stem cell characteristics. The dysregulation and abnormal activities of USP9X are influenced by intricate cellular signaling pathway crosstalk and upstream non-coding RNAs. The complex expression patterns and controversial clinical significance of USP9X in cancers suggest its potential as a prognostic biomarker. Furthermore, USP9X inhibitors has shown promising antitumor activity and holds the potential to overcome therapeutic resistance in preclinical models. However, a comprehensive summary of the role and molecular functions of USP9X in cancer progression is currently lacking. In this review, we provide a comprehensive delineation of USP9X participation in numerous critical cellular processes, complicated signaling pathways within the tumor microenvironment, and its potential translational applications to combat therapeutic resistance. By systematically summarizing the updated molecular mechanisms of USP9X in cancer biology, this review aims to contribute to the advancement of cancer therapeutics and provide essential insights for specialists and clinicians in the development of improved cancer treatment strategies.

Roles of USP9X in cellular functions and tumorigenesis (Review)

Ubiquitin-specific peptidase 9X (USP9X) is involved in certain human diseases, including malignancies, atherosclerosis and certain diseases of the nervous system. USP9X promotes the deubiquitination and stabilization of diverse substrates, thereby exerting a versatile range of effects on pathological and physiological processes. USP9X serves vital roles in the processes of cell survival, invasion and migration in various types of cancer. The present review aims to highlight the current knowledge of USP9X in terms of its structure and the possible mediatory mechanisms involved in certain types of cancer, providing a thorough introduction to its biological functions in carcinogenesis and further outlining its oncogenic or suppressive properties in a diverse range of cancer types. Finally, several perspectives regarding USP9X-targeted pharmacological therapeutics in cancer development are discussed.

A perspective to weaponize microRNAs against lung cancer

microRNAs are regulatory RNAs that silence specific mRNA by binding to it, inducing translational repression. Over the recent decades since the discovery of RNA interference, the field of microRNA therapeutics has expanded tremendously. The role of miRNAs in disease development has attracted researchers to investigate their potential in therapeutics. In lung cancer, multiple miRNAs are deregulated, and their involvement is observed in cell proliferation, immunomodulation, angiogenesis, and epithelial-mesenchymal transition. Thus, synthetic oligonucleotides are developed to downregulate the overexpressed miRNA or to upregulate the repressed miRNA. However, their clinical efficiency is limited due to the requirement for an effective delivery strategy. Advances in the current understanding of nanotechnology, biomaterial science, and disease molecular pathology have increased the chances of overcoming the limitations of miRNA-based therapy. This review enlists downregulated and upregulated miRNAs in lung cancer. This review also highlights the major contributions to miRNA-based therapeutics for lung cancer and strategies to overcome endosomal barriers. It also attempts to understand the nuances between current advancements in delivery methods, advantages, disadvantages, and practical issues for the large-scale development of miRNA-based therapeutics.

Disruption of USP9X in macrophages promotes foam cell formation and atherosclerosis

Subendothelial macrophage internalization of modified lipids and foam cell formation are hallmarks of atherosclerosis. Deubiquitinating enzymes (DUBs) are involved in various cellular activities; however, their role in foam cell formation is not fully understood. Here, using a loss-of-function lipid accumulation screening, we identified ubiquitin-specific peptidase 9 X-linked (USP9X) as a factor that suppressed lipid uptake in macrophages. We found that USP9X expression in lesional macrophages was reduced during atherosclerosis development in both humans and rodents. Atherosclerotic lesions from macrophage USP9X-deficient mice showed increased macrophage infiltration, lipid deposition, and necrotic core content than control apolipoprotein E–KO (Apoe^–/–) mice. Additionally, loss-of-function USP9X exacerbated lipid uptake, foam cell formation, and inflammatory responses in macrophages. Mechanistically, the class A1 scavenger receptor (SR-A1) was identified as a USP9X substrate that removed the K63 polyubiquitin chain at the K27 site. Genetic or pharmacological inhibition of USP9X increased SR-A1 cell surface internalization after binding of oxidized LDL (ox-LDL). The K27R mutation of SR-A1 dramatically attenuated basal and USP9X knockdown–induced ox-LDL uptake. Moreover, blocking binding of USP9X to SR-A1 with a cell-penetrating peptide exacerbated foam cell formation and atherosclerosis. In this study, we identified macrophage USP9X as a beneficial regulator of atherosclerosis and revealed the specific mechanisms for the development of potential therapeutic strategies for atherosclerosis.

LncRNA ELF3-AS1 Promotes Nonsmall Cell Lung Cancer Cell Invasion and Migration by Downregulating miR-212

LncRNA ELF3-AS1 has been characterized as an oncogenic lncRNA in bladder cancer and oral cancer, whereas its role in nonsmall cell lung cancer (NSCLC) is unknown. In this study, the authors observed that ELF3-AS1 was upregulated in NSCLC tissues in comparison with that in paired nontumor tissues collected from 68 NSCLC patients. High expression levels of ELF3-AS1 predicted the poor survival of NSCLC patients. Expression levels of miR-212 were inversely and significantly correlated with the expression levels of ELF3-AS1 across NSCLC tissue samples. In NSCLC cells, overexpression of ELF3-AS1 led to downregulated miR-212 and increased methylation of miR-212 gene. In addition, overexpression of ELF3-AS1 inhibited the role of miR-212 in suppressing cancer cell invasion and migration. Therefore, ELF3-AS1 is upregulated in NSCLC and promotes cancer cell invasion and migration by downregulating miR-212 through methylation.

MicroRNA-374b mediates the initiation of non-small cell lung cancer by regulating ITGB1 and p53 expressions

Background

Previous studies have shown that microRNAs (miRNAs) play important roles in the pathogenesis of human cancers. This study aims to clarify the role of miR‐374b in non‐small cell lung cancer (NSCLC).

Methods

In this study, RT‐qPCR and western blot analysis were used to measure mRNA and protein expression. The regulatory mechanism of miR‐374b/ITGB1 was investigated by dual‐luciferase reporter, CCK‐8, and transwell assays.

Results

MiR‐374b expression was reduced in NSCLC tissues and associated with lymph node metastasis, tumor stage and prognosis in NSCLC patients. Functionally, overexpression of miR‐374b inhibited cell viability and metastasis in NSCLC. In addition, miR‐374b blocked EMT and promoted p53 expression in NSCLC. MiR‐374b was found to directly target ITGB1. Furthermore, upregulation of ITGB1 weakened the antitumor effect of miR‐374b in NSCLC.

Conclusions

MiR‐374b inhibits the tumorigenesis of NSCLC by downregulating ITGB1 and upregulating p53.

The functions and targets of miR-212 as a potential biomarker of cancer diagnosis and therapy

Cancer is a major health problem worldwide. An increasing number of researchers are studying the diagnosis, therapy and mechanisms underlying the development and progression of cancer. The study of noncoding RNA has attracted a lot of attention in recent years. It was found that frequent alterations of miRNA expression not only have various functions in cancer but also that miRNAs can act as clinical markers of diagnosis, stage and progression of cancer. MiR-212 is an important example of miRNAs involved in cancer. According to recent studies, miR-212 may serve as an oncogene or tumour suppressor by influencing different targets or pathways during the oncogenesis and the development and metastasis of cancer. Its deregulation may serve as a marker for the diagnosis or prognosis of cancer. In addition, it was recently reported that miR-212 was related to the sensitivity or resistance of cancer cells to chemotherapy or radiotherapy. Here, we summarize the current understanding of miR-212 functions in cancer by describing the relevant signalling pathways and targets. The role of miR-212 as a biomarker and its therapeutic potential in cancer is also described. The aim of this review was to identify new methods for the diagnosis and treatment of human cancers.

miR-512-5p suppresses the progression of non-small cell lung cancer by targeting β-catenin

The oncogenic protein β-catenin is regulated by microRNAs (miRs) in non-small cell lung cancer (NSCLC). miR-512-5p is downregulated in NSCLC compared with healthy tissues and exhibits a tumour-suppressive effect. To study whether miR-512-5p acts on β-catenin to exert its anticancer effect in NSCLC, miR-512-5p mimic and inhibitor were transfected into NSCLC A549 and H1975 cells. miR-512-5p mimic inhibited the invasion of NSCLC cells and increased apoptosis, which suggested an inhibitory effect of miR-512-5p in NSCLC progression in vitro. By contrast, transfection with the miR-512-5p inhibitor resulted in the opposite effects. A dual-luciferase assay demonstrated that miR-512-5p complementarily bound to the 3′-untranslated region of β-catenin. miR-512-5p mimic suppressed the transcription and translation of β-catenin and reduced the expression of the downstream oncogenes cyclin D1 and matrix metalloproteinases, leading to the inhibition of Wnt/β-catenin signalling and subsequent inhibition of NSCLC tumourigenesis in vitro. In conclusion, miR-512-5p may function as a tumour suppressor in NSCLC by inhibiting the Wnt/β-catenin pathway.

microRNA-605 inhibits the oncogenicity of non-small-cell lung cancer by directly targeting Forkhead Box P1

Background and aims: microRNA-605 (miR-605) is dysregulated in multiple cancers and plays crucial roles in regulating cancer progression. However, little is known about the expression pattern and detailed roles of miR-605 in non-small-cell lung cancer (NSCLC). Thus, in this study, we evaluated miR-605 expression in NSCLC along with its clinical significance. More importantly, the detailed roles and the underlying molecular mechanisms of miR-605 in NSCLC were explored.

Material and methods: Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was employed to detect miR-605 expression in NSCLC tissues and cell lines. A series of experiments were performed to determine the effects of miR-605 upregulation on NSCLC cell proliferation, apoptosis, migration and invasion in vitro and tumor growth in vivo. In addition, the downstream regulatory mechanisms of miR‐605 action in NSCLC cells were explored.

Results: Decreased expression of miR-605 was frequently detected in NSCLC tissues and cell lines. Low expression of miR-605 was significantly correlated with the tumor size, TNM stage, and distane metastasis in NSCLC patients. Exogenous miR-605 expression inhibited proliferation, increased apoptosis, and inhibited metastasis of NSCLC cells in vitro. Additionally, miR-605 overexpression hindered the growth of NSCLC cells in vivo. Furthermore, Forkhead Box P1 (FOXP1) was identified as a direct target gene of miR-605 in NSCLC cells. Moreover, FOXP1 was highly expressed in NSCLC cells and showed an inverse correlation with miR-605 expression levels. Besides, silencing of FOXP1 simulated roles similar to miR-605 upregulation in NSCLC cells. FOXP1 reintroduction partially abolished the anticancer effects of miR-605 in NSCLC cells.

Conclusion: Our results revealed that miR-605 inhibited the oncogenicity of NSCLC cells in vitro and in vivo by directly targeting FOXP1, suggesting the importance of the miR-605/FOXP1 pathway in the malignant development of NSCLC.

Upregulation of microRNA 344a-3p is involved in curcumin induced apoptosis in RT4 schwannoma cells

Background

Schwannoma arising from peripheral nervous sheaths is a benign tumor.

Methods

To evaluate cell cytotoxicity, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction and terminal deoxynucleotidyltransferase UTP nick-end labeling (TUNEL) assays were used. A microRNA (miRNA) array was used to identify the miRNAs involved in curcumin-induced apoptosis. To examine miRNA expression, quantitative RT-PCR was used.

Results

In this study, curcumin exerted cellular cytotoxicity against RT4 schwannoma cells, with an increase in TUNEL-positive cells. Curcumin also activated the expression of apoptotic proteins, such as polyADP ribose polymerase, caspase-3, and caspase-9. The miRNA array revealed that seven miRNAs (miRNA 350, miRNA 17-2-3p, let 7e-3p, miRNA1224, miRNA 466b-1-3p, miRNA 18a-5p, and miRNA 322-5p) were downregulated following treatment with both 10 and 20 μM curcumin in RT4 cells, while four miRNAs (miRNA122-5p, miRNA 3473, miRNA182, and miRNA344a-3p) were upregulated. Interestingly, transfection with a miRNA 344a-3p mimic downregulated the mRNA expression of Bcl2 and upregulated that of Bax, Curcumin treatment in RT 4 cells also reduced the mRNA expression of Bcl2 and enhanced expression of Bax, Overexpression of miRNA344a-3p mimic combined with curcumin treatment activated the expression of apoptotic proteins, including procaspase-9 and cleaved caspase-3 while inhibition of miRNA 344a-3p using miR344a-3p inhibitor repressed cleaved caspase-3 and -9 in curcumin treated RT-4 cells compared to control.

Conclusions

Our findings demonstrate that curcumin induces apoptosis in schwannoma cells via miRNA 344a-3p. Thus, curcumin may serve as a potent therapeutic agent for the treatment of schwannoma.