Downregulation of miR-136 promotes the progression of osteosarcoma and is associated with the prognosis of patients with osteosarcoma

Research and progress of microRNA-136 in metastatic tumors

Background

MiR-136 is abnormally expressed in many types of metastatic tumors and is closely associated with tumor cell proliferation, apoptosis, invasion, and metastasis, indicating its important role in tumor development and progression. This review summarizes current knowledge regarding miR-136's molecular mechanisms, functional roles, and impact on chemotherapy in different human cancers.

Methods

A literature search was conducted in PubMed and Web of Science using "miR-136" and "metastatic tumors" as English keywords, and in CNKI and Wanfang databases using the same terms in Chinese. Studies related to miR-136 research in metastatic tumors and high-quality evidence from similar studies were included. Meta-analyses, dissertations, conference papers, low-quality articles, unavailable full-text articles, and republished articles were excluded.

Results

This review synthesizes the current understanding of miR-136's role in various cancers, including osteosarcoma, gastric cancer, gallbladder cancer, esophageal cancer, prostate cancer, colorectal cancer, breast cancer, glioma, and thyroid cancer. miR-136 acts as a tumor suppressor by targeting various genes, including MTDH, PTEN, MAP2K4, MUC1, LRH-1, MIEN1, RASAL2, CYR61, and KLF7. It influences multiple signaling pathways, including the ERK/mitogen-activated protein kinase, Wnt/β-catenin, Ha-Ras, PI3K/Akt, Aurora-A kinase, nuclear factor-κB, and JNK pathways. Furthermore, miR-136 is involved in chemoresistance by modulating ROCK1, PPP2R2A, and the miR-136-Notch3 signaling axis.

Conclusions

MiR-136 demonstrates promising potential as a novel biomarker and therapeutic target in various human cancers. Further research is needed to fully elucidate its complex roles in cancer development, progression, and drug resistance, particularly regarding its potential in immunotherapy.

Long Noncoding RNA CRNDE Promotes Gastric Cancer Progression through Targeting miR-136-5p/MIEN1

Background: Long noncoding RNAs (lncRNAs) contribute to the initiation and progression of gastric cancer (GC). This study examined the potential role of lncRNA colorectal neoplasia differentially expressed (CRNDE) in modulating the expression of migration and invasion enhancer 1 (MIEN1) through the suppression of miR-136-5p in GC. Methods: The biological roles of CRNDE, miR-136-5p, and MIEN1 in GC were assessed both in laboratory settings and through the examination of clinical samples. Results: CRNDE was found to be significantly increased in GC tissues, and this upregulation was associated with an unfavorable prognosis of GC patients. In vitro experiments showed that inhibiting cell growth and migration, along with promoting apoptosis in GC cells, could be achieved by either disabling CRNDE or MIEN1, or by increasing the expression of miR-136-5p. MIEN1 is a specific recipient of miR-136-5p, and the anticancer effects of miR-136-5p can be counteracted by the increased expression of MIEN1. Through the examination of clinical specimens, it has been observed that there is a significant positive correlation between the expression of MIEN1 and CRNDE. In contrast, miR-136-5p expression in GC tissues shows a negative correlation. Conclusion: A previously unexplored therapeutic target for GC involves the CRNDE/miR-136-5p/MIEN1 signal transduction cascade.

MicroRNA signatures differentiate types, grades, and stages of breast invasive ductal carcinoma (IDC): miRNA-target interacting signaling pathways

BACKGROUND

Invasive ductal carcinoma (IDC) is the most common form of breast cancer which accounts for 85% of all breast cancer diagnoses. Non-invasive and early stages have a better prognosis than late-stage invasive cancer that has spread to lymph nodes. The involvement of microRNAs (miRNAs) in the initiation and progression of breast cancer holds great promise for the development of molecular tools for early diagnosis and prognosis. Therefore, developing a cost effective, quick and robust early detection protocol using miRNAs for breast cancer diagnosis is an imminent need that could strengthen the health care system to tackle this disease around the world.

METHODS

We have analyzed putative miRNAs signatures in 100 breast cancer samples using two independent high fidelity array systems. Unique and common miRNA signatures from both array systems were validated using stringent double-blind individual TaqMan assays and their expression pattern was confirmed with tissue microarrays and northern analysis. In silico analysis were carried out to find miRNA targets and were validated with q-PCR and immunoblotting. In addition, functional validation using antibody arrays was also carried out to confirm the oncotargets and their networking in different pathways. Similar profiling was carried out in Brca2/p53 double knock out mice models using rodent miRNA microarrays that revealed common signatures with human arrays which could be used for future in vivo functional validation.

RESULTS

Expression profile revealed 85% downregulated and 15% upregulated microRNAs in the patient samples of IDC. Among them, 439 miRNAs were associated with breast cancer, out of which 107 miRNAs qualified to be potential biomarkers for the stratification of different types, grades and stages of IDC after stringent validation. Functional validation of their putative targets revealed extensive miRNA network in different oncogenic pathways thus contributing to epithelial-mesenchymal transition (EMT) and cellular plasticity.

CONCLUSION

This study revealed potential biomarkers for the robust classification as well as rapid, cost effective and early detection of IDC of breast cancer. It not only confirmed the role of these miRNAs in cancer development but also revealed the oncogenic pathways involved in different progressive grades and stages thus suggesting a role in EMT and cellular plasticity during breast tumorigenesis per se and IDC in particular. Thus, our findings have provided newer insights into the miRNA signatures for the classification and early detection of IDC.

Circular RNAs: Emerging Modulators in the Pathophysiology of Polycystic Ovary Syndrome and their Clinical Implications

Polycystic ovary syndrome (PCOS) is a prevalent endocrine/metabolic disorder in women of reproductive age. PCOS is characterized by hyperandrogenism, polycystic ovary morphology, and ovulatory dysfunction/anovulation. It involves multiple effects in patients, including granulosa/theca cell hyperplasia, menstrual disturbances, infertility, acne, obesity, insulin resistance, and cardiovascular disorders. Biochemical analyses and the results of RNA sequencing studies in recent years have shown a type of non-coding RNAs as a splicing product known as circular RNAs (circRNAs). Several biological functions have been identified in relation to circRNAs, including a role in miRNA sponge, protein sequestration, increased parental gene expression, and translation leading to polypeptides. These circular molecules are more plentiful and specialized than other types of RNAs. For this reason, they are referred to as potential biomarkers in different diseases. Evidence suggests that circRNAs may have regulatory potentials through different signaling pathways, such as the miRNA network. Probably most experts in the field of obstetricians are not aware of circRNAs as a useful biomarker. Therefore, this review focused on the researches that have been done on the involvement of circRNAs in PCOS and summarized recent supportive evidence, and evaluated the circRNA association and mechanisms involved in PCOS.

The Neuroprotective Effect of miR-136 on Pilocarpine-Induced Temporal Lobe Epilepsy Rats by Inhibiting Wnt/β-Catenin Signaling Pathway

Objective

To explore the effect of miR-136 on temporal lobe epilepsy (Ep) and its mechanism of action.

Methods

30 male rats were injected intraperitoneally with 30 mg/kg pilocarpine to construct a rat temporal lobe epilepsy model, and they were randomly divided into 5 groups (n = 6 per group): control group, Ep group, agomir NC group, miR-136 agomir group, and miR-136+LiCl group. The brain tissues of the rats were collected 7 days after the treatment. The expression of miR-136 in the hippocampus tissue was detected by qRT-PCR. H&E and Nissl staining were used to observe the histopathological changes and neuron damage in the hippocampus tissue. IL-1β, IL-6, and TNF-α levels in the hippocampus tissue were detected by ELISA. Flow cytometry was used to detect the apoptosis rate in the hippocampus tissue. Western blot was used to detect the expression levels of c-Caspase-3, Bcl-2, β-catenin, Cyclin D1, and c-myc protein in the hippocampus.

Results

The expression of miR-136 was significantly downregulated in the hippocampus tissue of epileptic rats. After overexpression of miR-136, the number of seizures and the duration of epilepsy in rats were significantly reduced. At the same time, hippocampal tissue damage was improved considerably, and the degree of neuronal damage decreased. Overexpression of miR-136 also significantly reduced the apoptosis rate in the hippocampus tissue and inhibited the levels of inflammatory factors. Meanwhile, miR-136 downregulates the expression of Wnt/β-catenin signaling pathway-related proteins. However, Wnt pathway activator LiCl could destroy the protective effect of miR-136.

Conclusion

miR-136 could exert its neuroprotective influence on temporal lobe epilepsy rats by inhibiting the Wnt/β-catenin signaling pathway.

Differential Expression of miR-136 in Gestational Diabetes Mellitus Mediates the High-Glucose-Induced Trophoblast Cell Injury through Targeting E2F1

Background

Gestational diabetes mellitus (GDM) seriously affects the health of mothers and infants. The high-glucose-induced inhibition in trophoblast cell viability is an important event in GDM pathogenesis. This study evaluated the expression and clinical significance of miR-136 in GDM patients, and the biological function and related mechanisms of miR-136 in the regulation of trophoblast cell proliferation were explored.

Methods

The expression of miR-136 in serum and placenta of GDM patients was measured using quantitative Real-Time PCR. Trophoblast cells were stimulated with high-glucose medium to mimic the pathological changes of GDM, and the effect of miR-136 was examined by CCK-8 assay. A luciferase reporter assay was used to confirm the target gene of miR-136, and the relationship of E2F transcription factor 1 (E2F1) with miR-136 in GDM was further analyzed.

Results

miR-136 expression was significantly elevated in GDM serum and tissue samples. By high-glucose treatment, trophoblast cell proliferation was inhibited and miR-136 expression was promoted. The knockdown of miR-136 could promote the proliferation of trophoblast cells exposed to high glucose, whereas the overexpression of miR-136 could suppress it. In addition, E2F1 was identified as a target gene of miR-136, which could mediate the regulatory effect of miR-136 on trophoblast cell proliferation.

Conclusion

Collectively, miR-136 expression is increased in both serum and placental tissues in GDM patients, and miR-136 mediates the inhibiting effect of high glucose on trophoblast cell viability by targeting E2F1.

Circ_0000043 promotes the proliferation, migration, invasiveness, and epithelial-mesenchymal transition in breast cancer cells via the miR-136-Smad3 axis

Circular RNAs (circRNAs) are tissue-specific RNAs with a more stable structure than linear RNAs, and their association with breast cancer (BC) is poorly understood. This study examined the biological effects of circ_0000043 in the progression of BC. In this study, expression of circ_0000043 in BC tissue samples was measured using quantitative real-time polymerase chain reaction. Immunohistochemistry and Western blot were used to detect the expression of Smad family member 3 (Smad3). CCK-8, wound healing, and Transwell assays were used to assess the effect of circ_0000043 on the proliferation, migration, and invasiveness of BC cells. Moreover, the binding relationships between circ_0000043 and miR-136, and miR-136 and Smad3 were detected by dual-luciferase reporter assay. Additionally, Western blot was used to detect the expressions of markers related to epithelial-mesenchymal transition, including E-cadherin, N-cadherin, and vimentin. Our results show that the expression of circ_0000043 is up-regulated in BC tissues and cell lines. The proliferation, migration, invasiveness, and epithelial-mesenchymal transition of BC cells were significantly inhibited by knockdown of circ_0000043, and overexpression of circ_0000043 had the opposite effects. Additionally, circ_0000043 up-regulate the expression of Smad3 by sponging miR-136. In conclusion, our study demonstrates that circ_0000043 promote the progression of BC via regulating the miR-136-Smad3 axis.

MicroRNA‑145‑5p inhibits osteosarcoma cell proliferation by targeting E2F transcription factor 3

Osteosarcoma is a common type of bone tumor that primarily occurs in children and young adults. MicroRNA (miRNA/miR) dysregulation is associated with the progression of osteosarcoma; therefore, the aim of the present study was to investigate the biological functions and molecular mechanisms of miR-145-5p in osteosarcoma. The expression of miR-145-5p in osteosarcoma tissues and cell lines was quantified using reverse transcription-quantitative PCR (RT-qPCR). The effect of miR-145-5p on the proliferation of osteosarcoma cells was detected using Cell Counting Kit-8 and colony formation assays, as well as cell cycle distribution analysis. The effect of miR-145-5p on tumor growth was further investigated in vivo using a subcutaneous tumor model in nude mice. The interaction between miR-145-5p and E2F transcription factor 3 (E2F3) was determined using bioinformatics analysis, a luciferase assay, RT-qPCR and western blotting. The results revealed that miR-145-5p expression was decreased in osteosarcoma cell lines and tissues compared with the corresponding normal controls. Increased miR-145-5p expression inhibited the proliferation and colony formation ability of osteosarcoma cells, and induced G₁ phase arrest. Furthermore, mice injected with tumor cells overexpressing miR-145-5p exhibited smaller tumors than those in the control group. Further investigation revealed that miR-145-5p binds to and decreases the expression of E2F3. In addition, the mRNA levels of E2F3 were negatively associated with miR-145-5p in osteosarcoma tissues, and increasing E2F3 expression abrogated the inhibitory effects of miR-145-5p on osteosarcoma cells. Collectively, the results obtained in the present study suggest that miR-145-5p may suppress the progression of osteosarcoma, and may serve as a useful biomarker for the diagnosis of osteosarcoma, as well as a therapeutic target.

Tumor Suppressor Function of miR-127-3p and miR-376a-3p in Osteosarcoma Cells

Since the introduction of high-dose chemotherapy about 35 years ago, survival rates of osteosarcoma patients have not been significantly improved. New therapeutic strategies replacing or complementing conventional chemotherapy are therefore urgently required. MicroRNAs represent promising targets for such new therapies, as they are involved in the pathology of multiple types of cancer, and aberrant expression of several miRNAs has already been shown in osteosarcoma. In this study, we identified silencing of miR-127-3p and miR-376a-3p in osteosarcoma cell lines and tissues and investigated their role as potential tumor suppressors in vitro and in vivo. Transfection of osteosarcoma cells (n = 6) with miR-127-3p and miR-376a-3p mimics significantly inhibited proliferation and reduced the colony formation capacity of these cells. In contrast, we could not detect any influence of miRNA restoration on cell cycle and apoptosis induction. The effects of candidate miRNA restoration on tumor engraftment and growth in vivo were analyzed using a chicken chorioallantoic membrane (CAM) assay. Cells transfected with mir-127-3p and miR-376a-3p showed reduced tumor take rates and tumor volumes and a significant decrease of the cumulative tumor volumes to 41% and 54% compared to wildtype cells. The observed tumor suppressor function of both analyzed miRNAs indicates these miRNAs as potentially valuable targets for the development of new therapeutic strategies for the treatment of osteosarcoma.

MicroRNA-99b predicts clinical outcome of osteosarcoma and suppresses tumor cell proliferation, migration and invasion

BACKGROUND

Osteosarcoma (OS) is a malignancy predominantly occurred in children and adolescents. Numerous microRNAs are involved in the pathogenesis of various cancers. This study aimed to investigate the expression profiles of miR-99b and its prognostic value in OS patients, and further analyze the biological function of miR-99b in the tumor progression by using OS cells.

METHODS

Expression of miR-99b was measured using quantitative real-time PCR. Kaplan-Meier survival curves and Cox regression analysis were performed to evaluate the prognostic value of miR-99b. OS cell lines were used to investigate the effects of miR-99b on cell proliferation, migration and invasion.

RESULTS

A significant decreased expression of miR-99b was observed in the OS tissues and cell lines respectively compared with the normal tissues and cells. Aberrant expression of miR-99b was associated with the patients' metastasis and TNM stage, and could be used to predict the prognosis of OS. The expression of miR-99b was regulated in vitro by cell transfection, and we found that the overexpression of miR-99b led to suppressed cell proliferation, migration and invasion, whereas the knockdown of miR-99b resulted in the opposite results.

CONCLUSIONS

In one word, the aberrantly expressed miR-99b serves a prognostic biomarker for OS patients. OS cell proliferation, migration and invasion can be inhibited by the overexpression of miR-99b, suggesting that the methods to increase miR-99b expression may be novel therapeutic strategies in OS.