RETRACTED: miR-367 regulation of DOC-2/DAB2 interactive protein promotes proliferation, migration and invasion of osteosarcoma cells

miRNAs as potential game-changers in bone diseases: Future medicinal and clinical uses

MicroRNAs (miRNAs), short, highly conserved non-coding RNA, influence gene expression by sequential mechanisms such as mRNA breakdown or translational repression. Many biological processes depend on these regulating substances, thus changes in their expression have an impact on the maintenance of cellular homeostasis and result in the emergence of a variety of diseases. Relevant studies have shown in recent years that miRNAs are involved in many stages of bone development and growth. Additionally, abnormal production of miRNA in bone tissues has been closely associated with the development of numerous bone disorders, such as osteonecrosis, bone cancer, and bone metastases. Many pathological processes, including bone loss, metastasis, the proliferation of osteosarcoma cells, and differentiation of osteoblasts and osteoclasts, are under the control of miRNAs. By bringing together the most up-to-date information on the clinical relevance of miRNAs in such diseases, this study hopes to further the study of the biological features of miRNAs in bone disorders and explore their potential as a therapeutic target.

Modulation of immunosuppressive cells and noncoding RNAs as immunotherapy in osteosarcoma

The most common bone cancer is osteosarcoma (OS), which mostly affects children and teenagers. Early surgical resection combined with chemotherapy significantly improves the prognosis of patients with OS. Existing chemotherapies have poor efficacy in individuals with distant metastases or inoperable resection, and these patients may respond better to novel immunotherapies. Immune escape, which is mediated by immunosuppressive cells in the tumour microenvironment (TME), is a major cause of poor OS prognosis and a primary target of immunotherapy. Myeloid-derived suppressor cells, regulatory T cells, and tumour-associated macrophages are the main immunosuppressor cells, which can regulate tumorigenesis and growth on a variety of levels through the interaction in the TME. The proliferation, migration, invasion, and epithelial-mesenchymal transition of OS cells can all be impacted by the expression of non-coding RNAs (ncRNAs), which can also influence how immunosuppressive cells work and support immune suppression in TME. Interferon, checkpoint inhibitors, cancer vaccines, and engineered chimeric antigen receptor (CAR-T) T cells for OS have all been developed using information from studies on the metabolic properties of immunosuppressive cells in TME and ncRNAs in OS cells. This review summarizes the regulatory effect of ncRNAs on OS cells as well as the metabolic heterogeneity of immunosuppressive cells in the context of OS immunotherapies.

MicroRNA-1-3p affects lung adenocarcinoma progression through E2F8 and regulating NF-кB pathway

E2F8 can modulate development and progression of various cancers including cervical cancer, breast cancer and hepatocellular carcinoma. But its mechanism in lung adenocarcinoma (LUAD) remains underexplored. In this study, we conducted a series of experiments including qRT-PCR, western blot, CCK-8, scratch healing assay, Transwell, and flow cytometry. Through these assays, we confirmed the notable overexpression of E2F8 in LUAD and its promoting effects on LUAD cell proliferation, migration and invasion. Subsequently, microRNA-1-3p that was negatively associated with E2F8 expression was identified through bioinformatics analysis. qRT-PCR was then carried out for quantification of microRNA-1-3p expression, which displayed low microRNA-1-3p expression in LUAD cells. In addition, dual-luciferase reporter gene assay was utilized for validating the targeted relationship between microRNA-1-3p and E2F8. The results denoted that microRNA-1-3p could bind to the promoter region of E2F8. Finally, the results of rescue experiment revealed that microRNA-1-3p negatively modulated E2F8 level. It regulated NF-κB pathway to repress LUAD cell proliferative, migratory, and invasive properties, lead to cell cycle arrest in G0/G1 phase, and enhance cell apoptosis level. This study unraveled that microRNA-1-3p/E2F8 constrained LUAD malignant progression through NF-κB pathway, which may provide possible targets for LUAD diagnosis and treatment.

MicroRNA-367 directly targets PIK3R3 to inhibit proliferation and invasion of oral carcinoma cells

Recently, microRNA-367 (miR-367) has been reported to function as both tumor suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer and lung cancer. However, the biological function of miR-367 and its precise mechanisms in oral squamous cell carcinoma (OSCC) have not been well clarified. The aim of the present study was to study the roles of miR-367/PIK3R3 axis in OSCC. The levels of PIK3R3 and miR-367 were detected by quantitative PCR assay in OSCC tissues and cell lines. Moreover, the biological roles of miR-367 and PIK3R3 in OSCC cells were assessed by cell proliferation and invasion. The mRNA and protein levels of PIK3R3 were determined by using quantitative PCR and Western blotting assays. Luciferase assays were used to confirm that PIK3R3 was one target of miR-367. In the present study, the miR-367 level was dramatically reduced in OSCC tissues and cell lines, and the PIK3R3 expression was significantly enhanced. What’s more, the PIK3R3 expression was negatively related to the miR-367 level in OSCC tissues. Furthermore, up-regulation of miR-367 obviously restrained OSCC cells proliferation and invasion. We confirmed that miR-367 could directly target PIK3R3 by luciferase reporter assay. Besides, knockdown of PIK3R3 also could markedly inhibit the proliferation and invasion of OSCC cells. Finally, overexpression of miR-367 in OSCC cells partially reversed the promoted effects of PIK3R3 up-regulation. Overexpression of miR-367 restrained OSCC cells proliferation and invasion via regulation of PIK3R3.

Noncoding RNAs in osteosarcoma: Implications for drug resistance

Osteosarcoma is the most frequent bone malignancy in children and adolescents. Despite advances of surgery and chemotherapy in osteosarcoma over the past decades, overall survival rates of osteosarcoma have reached a plateau. The development of multi-drug resistance (MDR) has become the main obstacle in improving chemotherapeutic effects in osteosarcoma treatment. Therefore, understanding detailed mechanisms of chemoresistance and developing novel therapeutic targets to overcome chemoresistance are crucial to improve the prognosis of osteosarcoma patients. Accumulating evidence has proved that multiple noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) play pivotal roles in osteosarcoma progression. Notably, a great number of ncRNAs are abnormally expressed and can regulate chemosensitivity through various mechanisms in osteosarcoma. In this review, we systematically summarize the roles of ncRNAs as well as the molecular mechanisms in modulating drug resistance of osteosarcoma and discuss the potential roles of ncRNAs as biomarkers and novel therapeutic targets for osteosarcoma.

Cutting the Brakes on Ras-Cytoplasmic GAPs as Targets of Inactivation in Cancer

Simple Summary

GTPase-Activating Proteins (RasGAPs) are a group of structurally related proteins with a fundamental role in controlling the activity of Ras in normal and cancer cells. In particular, loss of function of RasGAPs may contribute to aberrant Ras activation in cancer. Here we review the multiple molecular mechanisms and factors that are involved in downregulating RasGAPs expression and functions in cancer. Additionally, we discuss how extracellular stimuli from the tumor microenvironment can control RasGAPs expression and activity in cancer cells and stromal cells, indirectly affecting Ras activation, with implications for cancer development and progression.

Abstract

The Ras pathway is frequently deregulated in cancer, actively contributing to tumor development and progression. Oncogenic activation of the Ras pathway is commonly due to point mutation of one of the three Ras genes, which occurs in almost one third of human cancers. In the absence of Ras mutation, the pathway is frequently activated by alternative means, including the loss of function of Ras inhibitors. Among Ras inhibitors, the GTPase-Activating Proteins (RasGAPs) are major players, given their ability to modulate multiple cancer-related pathways. In fact, most RasGAPs also have a multi-domain structure that allows them to act as scaffold or adaptor proteins, affecting additional oncogenic cascades. In cancer cells, various mechanisms can cause the loss of function of Ras inhibitors; here, we review the available evidence of RasGAP inactivation in cancer, with a specific focus on the mechanisms. We also consider extracellular inputs that can affect RasGAP levels and functions, implicating that specific conditions in the tumor microenvironment can foster or counteract Ras signaling through negative or positive modulation of RasGAPs. A better understanding of these conditions might have relevant clinical repercussions, since treatments to restore or enhance the function of RasGAPs in cancer would help circumvent the intrinsic difficulty of directly targeting the Ras protein.

Role of miR-302/367 cluster in human physiology and pathophysiology

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate target mRNAs at the post-transcriptional level. Increasing evidence shows the involvement of miRNAs in diverse biological processes. miR-302/367 cluster is highly conserved among vertebrates and made up of five members, including miR-367, miR-302a, miR-302b, miR-302c and miR-302d. miR-302/367 cluster plays an important role in cell proliferation, differentiation and reprogramming, affecting the development of tumor, cardiovascular system, nervous system and immune system. In this review, we will summarize the role of miR-302/367 cluster in embryonic stem cells and induced pluripotent stem cells and try to point out its relationship with tumors, cardiovascular system, nervous system and immune system.

miR-938 promotes cell proliferation by regulating RBM5 in lung adenocarcinoma cells

A growing body of research suggests that microRNAs (miRNAs) may play a key part in the progression of various cancers, including lung adenocarcinoma (LUAD). However, the expression and mechanism of miR-938 (microRNA-938) in LUAD have not been defined. Compared with adjacent tissues, the level of miR-938 was up-regulated in LUAD tissues. miR-938 expression was significantly associated with tumor size. In vitro assays indicated that miR-938 expression was also increased in the LUAD cell lines. Overexpression of miR-938 promoted LUAD cell proliferation, whereas down-regulation of miR-938 had the opposite effect. We identified RNA-binding protein 5 (RBM5) as a potential target gene of miR-938 in LUAD. Expression of RBM5 was down-regulated in LUAD tumor tissues and negatively correlated with expression of miR-938. Up-regulation of RBM5 reversed cell proliferation by inhibition of miR-938 expression in LUAD cells. These results showed that miR-938 may act as an oncogenic miRNA by targeting RBM5 in LUAD, indicating that miR-938 could be used as a potential therapeutic target for LUAD patients.

MicroRNA-367-3p overexpression represses the proliferation and invasion of cervical cancer cells through downregulation of SPAG5-mediated Wnt/β-catenin signalling

MicroRNA-367-3p (miR-367-3p) has been previously reported as a cancer-related miRNA that is dysregulated in various cancer types and functions either as an oncogenic or as tumour suppressive miRNA. However, whether miR-367-3p is dysregulated in cervical cancer and, further, whether it contributes to the development and progression of the disease remains unknown. Here, our results demonstrated that miR-367-3p expression was markedly decreased in both cervical cancer tissues and cell lines compared with corresponding controls. In vitro experiments revealed that miR-367-3p overexpression repressed the proliferation and invasion of cervical cancer cells. Notably, sperm-associated antigen 5 (SPAG5) was identified as a target gene of miR-367-3p. Moreover, decreased expression of miR-367-3p was correlated with high expression of SPAG5 in cervical cancer tissue specimens. SPAG5 inhibition or miR-367-3p overexpression significantly downregulated Wnt/β-catenin signalling in cervical cancer cells. However, the antitumour effect mediated by miR-367-3p overexpression was partially reversed by SPAG5 overexpression. Overall, these findings demonstrate that miR-367-3p overexpression restricts the proliferation and invasion of cervical cancer cells through targeting SPAG5 to downregulate Wnt/β-catenin signalling, suggesting a mechanism for the tumour suppressive function of miR-367-3p in cervical cancer. Our study highlights the involvement of miR-367-3p/SPAG5/Wnt/β-catenin signalling axis in regulating the malignant progression of cervical cancer.

miR-367 as a therapeutic target in stem-like cells from embryonal central nervous system tumors

Aberrant expression of the pluripotency factor OCT4A in embryonal tumors of the central nervous system (CNS) is a key factor that contributes to tumor aggressiveness and correlates with poor patient survival. OCT4A overexpression has been shown to up-regulate miR-367, a microRNA (miRNA) that regulates pluripotency in embryonic stem cells and stem-like aggressive traits in cancer cells. Here, we show that (a) miR-367 is carried in microvesicles derived from embryonal CNS tumor cells expressing OCT4A; and (b) inhibition of miR-367 in these cells attenuates their aggressive traits. miR-367 silencing in OCT4A-overexpressing tumor cells significantly reduced their proliferative and invasive behavior, clonogenic activity, and tumorsphere generation capability. In vivo, targeting of miR-367 through direct injections of a specific inhibitor into the cerebrospinal fluid of Balb/C nude mice bearing OCT4A-overexpressing tumor xenografts inhibited tumor development and improved overall survival. miR-367 was also shown to target SUZ12, one of the core components of the polycomb repressive complex 2 known to be involved in epigenetic silencing of pluripotency-related genes, including POU5F1, which encodes OCT4A. Our findings reveal possible clinical applications of a cancer stemness pathway, highlighting miR-367 as a putative liquid biopsy biomarker that could be further explored to improve early diagnosis and prognosis prediction, and potentially serve as a therapeutic target in aggressive embryonal CNS tumors.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

miR-1307-3p promotes tumor growth and metastasis of hepatocellular carcinoma by repressing DAB2 interacting protein

Increasing studies provide evidence to support that microRNAs (miRNAs) play important roles in regulating hepatocellular carcinoma (HCC) initiation and progression. However, whether miR-1307-3p is aberrantly expressed in HCC and affects malignant behaviors of cancer cells remain unknown. In this study, we found that miR-1307-3p expression was obviously up-regulated in HCC compared to adjacent nontumor tissues. Moreover, miR-1307-3p expression was prominently higher in HCC cells compared with the normal hepatic cell line LO2. Patients with venous infiltration, tumor size ≥5 cm and advanced tumor stages (III + IV) had significant higher levels of miR-1307-3p in HCC tissues. Notably, the high level of miR-1307-3p predicted poor clinical outcomes of HCC patients. Functionally, miR-1307-3p knockdown inhibited the proliferation, migration and invasion of MHCC97H and HCCLM3 cells, and suppressed the in vivo growth and metastasis of HCCLM3 cells. Conversely, overexpression of miR-1307-3p facilitated Hep3B cell proliferation, migration and invasion. Mechanistically, DAB2 interacting protein (DAB2IP) was screened as a direct target of miR-1307-3p. The expression of DAB2IP mRNA was down-regulated and inversely correlated with miR-1307-3p level in HCC tissues. miR-1307-3p knockdown increased the level of DAB2IP in HCC cells. Luciferase reporter assay confirmed the direct interaction between miR-1307-3p and 3'UTR of DAB2IP. Importantly, DAB2IP overexpression significantly suppressed the proliferation, migration and invasion of HCCLM3 cells. DAB2IP knockdown rescued miR-1307-3p silencing-attenuated HCC cell proliferation, migration and invasion. Taken together, our findings suggest that miR-1307-3p plays a driving role in HCC progression by targeting DAB2IP. Our study may provide new therapeutic targets for HCC treatment.

Circular RNA YAP1 inhibits the proliferation and invasion of gastric cancer cells by regulating the miR-367-5p/p27 Kip1 axis

Background

Circular RNAs (circRNAs) are a new type of non-coding RNAs and their functions in gastric cancer (GC) remain unclear. Recent studies have revealed that circRNAs play an important role in cancer development and certain types of pathological responses, acting as microRNA (miRNA) sponges to regulate gene expression.

Methods

CircNet was used to screen potential circRNAs and validated circYAP1 expression levels in 17 GC tissues by quantitative real-time PCR (qRT-PCR) and another 80 paired GC tissues by FISH. CircYAP1 overexpression and knockdown experiments were conducted to assess the effects of circYAP1 in vitro and in vivo, and its molecular mechanism was demonstrated by RNA in vivo precipitation assays, western blotting, luciferase assay and rescue experiments.

Results

CircYAP1 expression level was significantly lower in GC tissues than the adjacent normal tissues, and GC patients with circYAP1 low expression had shorter survival times as compared with those with circYAP1 high expression. Functionally, circYAP1 overexpression inhibited cell growth and invasion in vitro and in vivo, but its knockdown reversed these effects. Further analysis showed that circYAP1 sponged miR-367-5p to inhibit p27 ^Kip1 expression and GC progression.

Conclusion

Our findings demonstrate that circYAP1 functions as a tumor suppressor in GC cells by targeting the miR-367-5p/p27 ^Kip1 axis and may provide a prognostic indicator of survival in GC patients.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0902-1) contains supplementary material, which is available to authorized users.

miR‑590‑5p suppresses osteosarcoma cell proliferation and invasion via targeting KLF5

Recently, microRNA (miR)‑590‑5p has been shown to inhibit tumorigenesis in colorectal and breast cancer; however, its function in osteosarcoma (OS) requires further investigation. In the present study miR‑590‑5p expression was poorly expressed in OS samples and cell lines when compared with that observed in normal cells. In addition, overexpression of miR‑590‑5p significantly reduced the proliferation, migration and invasion of SAOS2 and U2OS cells in vitro, as well as inhibiting tumor sizes in vivo. The results revealed that miR‑590‑5p directly targeted Kruppel‑like factor 5 (KLF5) in SAOS2 and U2OS cells. Their expression was inversely correlated with OS tissues. Finally, it was demonstrated that overexpression of KLF5 rescued the inhibitory effects of miR‑590‑5p on cell proliferation, migration and invasion. Overall, the results of the present study suggested that the miR‑590‑5p/KLF5 axis may regulate OS progression and thus, may be a novel therapeutic target for the treatment of patients with OS.

miR-142-5p regulates CD4+ T cells in human non-small cell lung cancer through PD-L1 expression via the PTEN pathway

The present study aimed to evaluate the function of microRNA (miR)-142-5p on cancer immunity to induce apoptosis in human non-small cell lung cancer (NSCLC) and its mechanism. miR-142-5p expression was upregulated, and CD4⁺ T cell levels were reduced in patients with NSCLC. Overexpression of miR-142-5p expression inhibited the cancer effects of CD4⁺ T cells on NSCLC cell lines, and downregulation of miR-142-5p increased the cancer effects of CD4⁺ T cells on NSCLC cell lines, compared with the control group. In addition, we found that overexpression of miR-142-5p suppressed PTEN protein expression and induced PI3K, p-Akt and PD-L1 protein expression in an in vitro model of NSCLC. Downregulation of miR-142-5p induced PTEN and PD-L1 protein expression and suppressed PI3K and p-Akt and protein expression in an in vitro model of NSCLC. The suppression of PD-L1 reduced the cancer effects of CD4⁺ T cells on NSCLC cell lines following miR-142-5p downregulation. The inhibition of PTEN also reduced the cancer effects of CD4⁺ T cells on NSCLC cell lines following miR-142-5p downregulation. Therefore, our study demonstrated that miR-142-5p regulated CD4⁺ T cells in human NSCLC through PD-L1 expression via the PTEN pathway.