miR-17-5p and miR-4443 Promote Esophageal Squamous Cell Carcinoma Development by Targeting TIMP2

Non‑coding RNA: A promising diagnostic biomarker and therapeutic target for esophageal squamous cell carcinoma (Review)

Esophageal cancer (EC) is a common form of malignant tumor in the digestive system that is classified into two types: Esophageal squamous cell carcinomas (ESCC) and esophageal adenocarcinoma. ESCC is known for its early onset of symptoms, which can be difficult to identify, as well as its rapid progression and tendency to develop drug resistance to chemotherapy and radiotherapy. These factors contribute to the high incidence of disease and low cure rate. Therefore, a diagnostic biomarker and therapeutic target need to be identified for ESCC. Non-coding RNAs (ncRNAs) are a class of molecules that are transcribed from DNA but do not encode proteins. Initially, ncRNAs were considered to be non-functional segments generated during transcription. However, with advancements in high-throughput sequencing technologies in recent years, ncRNAs have been associated with poor prognosis, drug resistance and progression of ESCC. The present study provides a comprehensive overview of the biogenesis, characteristics and functions of ncRNAs, particularly focusing on microRNA, long ncRNAs and circular RNAs. Furthermore, the ncRNAs that could potentially be used as diagnostic biomarkers and therapeutic targets for ESCC are summarized to highlight their application value and prospects in ESCC.

MicroRNAs: A novel signature in the metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor, characterized by squamous cell differentiation, it is the sixth leading cause of cancer-related deaths globally. The increased mortality rate of ESCC patients is predominantly due to the advanced stage of the disease when discovered, coupled with higher risk of metastasis, which is an exceedingly malignant characteristic of cancer, frequently leading to a high mortality rate. Unfortunately, there is currently no specific and effective marker to predict and treat metastasis in ESCC. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules, approximately 22 nucleotides in length. miRNAs are vital in modulating gene expression and serve pivotal regulatory roles in the occurrence, progression, and prognosis of cancer. Here, we have examined the literature to highlight the intimate correlations between miRNAs and ESCC metastasis, and show that ESCC metastasis is predominantly regulated or regulated by genetic and epigenetic factors. This review proposes a potential role for miRNAs as diagnostic and therapeutic biomarkers for metastasis in ESCC metastasis, with the ultimate aim of reducing the mortality rate among patients with ESCC.

Upregulated expression of miR-4443 and miR-4488 in drug resistant melanomas promotes migratory and invasive phenotypes through downregulation of intermediate filament nestin

BACKGROUND

BRAF-mutant melanoma patients benefit from the combinatorial treatments with BRAF and MEK inhibitors. However, acquired drug resistance strongly limits the efficacy of these targeted therapies in time. Recently, many findings have underscored the involvement of microRNAs as main drivers of drug resistance. In this context, we previously identified a subset of oncomiRs strongly up-regulated in drug-resistant melanomas. In this work, we shed light on the molecular role of two as yet poorly characterized oncomiRs, miR-4443 and miR-4488.

METHODS

Invasion and migration have been determined by wound healing, transwell migration/invasion assays and Real Time Cell Analysis (RTCA) technology. miR-4488 and miR-4443 have been measured by qRT-PCR. Nestin levels have been tested by western blot, confocal immunofluorescence, immunohistochemical and flow cytometry analyses.

RESULTS

We demonstrate that the two oncomiRs are responsible for the enhanced migratory and invasive phenotypes, that are a hallmark of drug resistant melanoma cells. Moreover, miR-4443 and miR-4488 promote an aberrant cytoskeletal reorganization witnessed by the increased number of stress fibers and cellular protrusions-like cancer cell invadopodia. Mechanistically, we identified the intermediate filament nestin as a molecular target of both oncomiRs. Finally, we have shown that nestin levels are able to predict response to treatments in melanoma patients.

CONCLUSIONS

Altogether these findings have profound translational implications in the attempt i) to develop miRNA-targeting therapies to mitigate the metastatic phenotypes of BRAF-mutant melanomas and ii) to identify novel biomarkers able to guide clinical decisions.

Circ-FNDC3B Functions as an Oncogenic Factor in Esophageal Squamous Cell Carcinoma via Upregulating MYO5A by Absorbing miR-136-5p and miR-370-3p

Circular RNAs (circRNAs) are a class of key regulators in cancers via regulating gene levels by acting as sponges of miRNAs. This study was devoted to explore the functional mechanism of circRNA fibronectin type III domain-containing protein 3B (circ-FNDC3B) in esophageal squamous cell carcinoma (ESCC). RNA levels were examined via reverse transcription-quantitative polymerase chain reaction assay. Cell viability detection was performed using Cell Counting Kit-8 assay. The proliferation ability was determined through colony formation assay and EDU assay. Flow cytometry was applied for analysis of apoptosis. Invasion ability was assessed via transwell assay. Target binding was analyzed by dual-luciferase reporter assay. The protein expression was measured using western blot. In vivo research was conducted via xenograft model in mice. Circ-FNDC3B exhibited significant upregulation in ESCC tissues and cells. Downregulation of circ-FNDC3B inhibited ESCC cell proliferation and invasion but accelerated cell apoptosis. Circ-FNDC3B interacted with miR-136-5p or miR-370-3p. The function of circ-FNDC3B was achieved by sponging miR-136-5p or miR-370-3p. Myosin VA (MYO5A) acted as a downstream target of miR-136-5p or miR-370-3p. MYO5A reversed miR-136-5p/miR-370-3p-induced tumor inhibition in ESCC cells. Circ-FNDC3B targeted miR-136-5p or miR-370-3p to affect MYO5A expression. Circ-FNDC3B knockdown reduced tumor growth in vivo by inhibiting miR-136-5p or miR-370-3p-mediated MYO5A expression. These findings demonstrated that circ-FNDC3B contributed to malignant progression of ESCC cells via miR-136-5p/MYO5A or miR-370-3p/MYO5A axis.

Unraveling Therapeutic Opportunities and the Diagnostic Potential of microRNAs for Human Lung Cancer

Lung cancer is a major public health problem and a leading cause of cancer-related deaths worldwide. Despite advances in treatment options, the five-year survival rate for lung cancer patients remains low, emphasizing the urgent need for innovative diagnostic and therapeutic strategies. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets for lung cancer due to their crucial roles in regulating cell proliferation, differentiation, and apoptosis. For example, miR-34a and miR-150, once delivered to lung cancer via liposomes or nanoparticles, can inhibit tumor growth by downregulating critical cancer promoting genes. Conversely, miR-21 and miR-155, frequently overexpressed in lung cancer, are associated with increased cell proliferation, invasion, and chemotherapy resistance. In this review, we summarize the current knowledge of the roles of miRNAs in lung carcinogenesis, especially those induced by exposure to environmental pollutants, namely, arsenic and benzopyrene, which account for up to 1/10 of lung cancer cases. We then discuss the recent advances in miRNA-based cancer therapeutics and diagnostics. Such information will provide new insights into lung cancer pathogenesis and innovative diagnostic and therapeutic modalities based on miRNAs.

miR-4443 promotes radiation resistance of esophageal squamous cell carcinoma via targeting PTPRJ

BACKGROUND

Radiotherapy is one of the main treatments for esophageal squamous cell carcinoma (ESCC), but its efficacy is limited by radioresistance. MicroRNAs play a crucial role in posttranscriptional regulation, which is linked to the cancer response to radiation.

METHODS

We successfully established a radioresistant cell line model by using fractionated irradiation. qRT-PCR was adopted to detect the expression of miR-4443 in human normal esophageal cell lines, tumor cells, and radioresistant cells. Next, CCK-8, colony formation, apoptosis, and cell cycle assays were used to assess the biological effect of miR-4443. Weighted gene coexpression network analysis (WGCNA) was performed to identify potential radiosensitivity-related genes. Additionally, we predicted the probable targets of the miRNA using bioinformatic methods and confirmed them using Western blot.

RESULTS

miR-4443 was significantly upregulated in radioresistant ESCC cells. Enhancement of miR-4443 further decreased the radiosensitivity of ESCC cells, while inhibition of miR-4443 increased the radiosensitivity of ESCC cells. Notably, miR-4443 modulated radiosensitivity by influencing DNA damage repair, apoptosis, and G2 cycle arrest. By using WGCNA and experimental validation, we identified PTPRJ as a key target for miRNA-4443 to regulate radiosensitivity. The effects of miR-4443 overexpression or inhibition could be reversed by increasing or decreasing PTPRJ expression.

CONCLUSION

In this study, miR-4443 is found to promote radiotherapy resistance in ESCC cells by regulating PTPRJ expression, which provides a new perspective and clue to alleviate radioresistance.

miR-4443/MMP2 suppresses the migration and invasion of trophoblasts through the HB-EGF/EGFR pathway in preeclampsia

Preeclampsia (PE) is a pregnancy-associated disease that may cause maternal and fetal morbidity and mortality. The dysregulation of microRNAs (miRNAs) and their potential functions has been an important direction for elucidating the mechanism of preeclampsia in recent years. The present study investigated whether miR-4443 was significantly increased in the placentas of severe preeclamptic patients, and the upregulation of miR-4443 inhibited the migration and invasion of HTR-8/SVneo cells according to transwell assays. Matrix metallopeptidase 2 (MMP2), which is involved in the degradation of extracellular matrix (ECM) components and harbors a miR-4443-binding site within its 3'-UTR as confirmed by a luciferase reporter assay, was identified to be directly inhibited by miR-4443. Moreover, siRNA targeting MMP2 imitated the effects of overexpressed miR-4443 on HTR-8/SVneo cell invasion and migration, whereas rescue experiments showed that MMP2 reversed this inhibitory function of miR-4443. Heparin-binding EGF-like growth factor (HB-EGF), as the downstream gene of MMP2, plays an important role in trophoblast invasion, and we confirmed that the expression of HB-EGF/EGFR pathway-related biomolecules was consistent with MMP2 influenced by upregulating and downregulating miR-4443 and that activated EGFR further transmitted intracellular downstream signaling via the MAPK pathway according to western blot assay. In conclusion, we demonstrated that miR-4443 suppresses the migration and invasion of trophoblasts, and its inhibitory effects are at least partially mediated by the suppression of MMP2. This inhibition might further affect the progression of preeclampsia through the HB-EGF/EGFR pathway, thus providing a new clue on the role of miR-4443 in the pathogenesis of preeclampsia.

Loss of miR-637 promotes cancer cell stemness via WASH/IL-8 pathway and serves as a novel prognostic marker in esophageal squamous cell carcinoma

BACKGROUND

Esophageal carcinoma is the highly lethal cancer in the world, predominantly in some areas of East Asia. We previously reported that overexpression of cytoskeleton regulator Wiskott-Aldrich syndrome protein and SCAR Homolog (WASH) associates with poor prognosis of patients with esophageal squamous cell carcinoma (ESCC). However, the molecular mechanism and clinical significance involved in WASH overexpression have not been fully elucidated.

METHODS

Bioinformatics analysis and luciferase reporter assay were used to predict and validate miR-637 as a regulator of WASH in ESCC cell lines. qRT-PCR, Western blotting and ELISA assays were performed to examine RNA expression and protein levels, respectively. Next, the biological functions of miR-637 were explored by tumor sphere formation assay in vitro and nude mouse tumor xenograft in vivo. Finally, we evaluated the association of miR-637 levels with clinical features in ESCC patients.

RESULTS

We identified miR-637 as a WASH-targeting miRNA. miR-637 mimic strongly attenuated the downstream IL-8 production and tumor sphere formation in esophageal cancer cells, whereas miR-637 inhibitor displayed an opposite effect. IL-8 could facilitate stem-like properties and partially rescue the phenotypes induced by miR-637 mimic. Furthermore, miR-637 inhibitor dramatically promoted IL-8 expression and cancer stemness properties in a WASH-dependent manner. Ectopic expression of miR-637 also inhibited tumor growth in a mouse model. Clinically, low expression of miR-637 was observed in tumor tissues and the low expression levels of miR-637 were correlated with poor survival of ESCC patients. In particular, plasma miR-637 could be used as a noninvasive biomarker for ESCC patients.

CONCLUSIONS

These results implicate the potential application of miR-637 for diagnosis and prognosis of esophageal cancer.

The Role and Interactions of Programmed Cell Death 4 and its Regulation by microRNA in Transformed Cells of the Gastrointestinal Tract

Data from GLOBOCAN 2020 estimates that there were 19.3 million new cases of cancer and 10.0 million cancer-related deaths in 2020 and that this is predicted to increase by 47% in 2040. The combined burden of cancers of the gastrointestinal (GI) tract, including oesophageal-, gastric- and colorectal cancers, resulted in 22.6% of the cancer-related deaths in 2020 and 18.7% of new diagnosed cases. Understanding the aetiology of GI tract cancers should have a major impact on future therapies and lessen this substantial burden of disease. Many cancers of the GI tract have suppression of the tumour suppressor Programmed Cell Death 4 (PDCD4) and this has been linked to the expression of microRNAs which bind to the untranslated region of PDCD4 mRNA and either inhibit translation or target the mRNA for degradation. This review highlights the properties of PDCD4 and documents the evidence for the regulation of PDCD4 expression by microRNAs in cancers of the GI tract.

Exosomal miR-483-5p in Bone Marrow Mesenchymal Stem Cells Promotes Malignant Progression of Multiple Myeloma by Targeting TIMP2

Bone marrow-derived mesenchymal stem cell (BMSC) is one crucial component of the multiple myeloma (MM) microenvironment and supports the malignant progression of MM. Whether BMSCs act on MM cells via exosomes has not been well characterized. Herein, we used microarrays to screen out differentially expressed miRNAs in BMSCs from patients with MM (MM-MSCs) or benign diseases (BD-MSCs). We found that miR-483-5p was highly expressed in MM-MSCs, which may be transported through exosomes from MM-MSCs to MM cells to increase miR-483-5p expression in them. We then investigated the role and mechanism of miR-483-5p in the aggressive progression of MM in vitro. We verified that miR-483-5p promoted MM cell proliferation and reduced apoptosis. Then we predicted and validated that TIMP2, a tumor suppressor gene, is the downstream target of miR-483-5p in MM. In summary, our study indicated that MM-MSCs promote MM malignant progression via the release of exosomes and regulation of miR-483-5p/TIMP2 axis, suggesting an essential role of BMSCs derived exosomal miRNA in MM and a potential marker for MM diagnosis and therapy.