Long non-coding RNA FGD5-AS1 enhances osteosarcoma cell proliferation and migration by targeting miR-506-3p/RAB3D axis

Osteosarcoma in a ceRNET perspective

Osteosarcoma (OS) is the most prevalent and fatal type of bone tumor. It is characterized by great heterogeneity of genomic aberrations, mutated genes, and cell types contribution, making therapy and patients management particularly challenging. A unifying picture of molecular mechanisms underlying the disease could help to transform those challenges into opportunities.This review deeply explores the occurrence in OS of large-scale RNA regulatory networks, denominated "competing endogenous RNA network" (ceRNET), wherein different RNA biotypes, such as long non-coding RNAs, circular RNAs and mRNAs can functionally interact each other by competitively binding to shared microRNAs. Here, we discuss how the unbalancing of any network component can derail the entire circuit, driving OS onset and progression by impacting on cell proliferation, migration, invasion, tumor growth and metastasis, and even chemotherapeutic resistance, as distilled from many studies. Intriguingly, the aberrant expression of the networks components in OS cells can be triggered also by the surroundings, through cytokines and vesicles, with their bioactive cargo of proteins and non-coding RNAs, highlighting the relevance of tumor microenvironment. A comprehensive picture of RNA regulatory networks underlying OS could pave the way for the development of innovative RNA-targeted and RNA-based therapies and new diagnostic tools, also in the perspective of precision oncology.

Overexpression of miR-506-3p reversed doxorubicin resistance in drug-resistant osteosarcoma cells

Background and objective: Osteosarcoma is a common primary malignant tumor of bone, and doxorubicin is one of the most widely used therapeutic drugs. While the problem of doxorubicin resistance limits the long-term treatment benefits in osteosarcoma patients. The role of miRNAs and their target genes in osteosarcoma have become increasingly prominent. Currently, there is no report on miR-506-3p reversing doxorubicin resistance by targeting STAT3 in osteosarcoma. The purpose of this study was to investigate the molecular mechanism that overexpression of miR-506-3p reverses doxorubicin resistance in drug-resistant osteosarcoma cells. Methods: Doxorubicin-resistant osteosarcoma cells (U-2OS/Dox) were constructed by intermittent stepwise increasing stoichiometry. The target genes of miR-506-3p were predicted by bioinformatics approach and the targeting relationship between miR-506-3p and STAT3 was detected using dual luciferase reporter assay. U-2OS/Dox cells were treated with miR-506-3p overexpression and STAT3 silencing respectively. Then Western blot and RT-qPCR were used to detect the protein and mRNA expression levels of JAK2/STAT3 signaling pathway, drug-resistant and apoptotic associated molecules. The migration and invasion were assessed by cell scratch assay and transwell assay. The cell proliferative viability and apoptosis were investigated by CCK8 assay and flow cytometry assay. Results: U-2OS/Dox cells were successfully constructed with a 14.4-fold resistance. MiR-506-3p is directly bound to the 3'-UTR of STAT3 mRNA. Compared with U-2OS cells, the mRNA expression of miR-506-3p was reduced in U-2OS/Dox cells. Overexpression of miR-506-3p decreased the mRNA expression levels of JAK2, STAT3, MDR1/ABCB1, MRP1/ABCC1, Survivin and Bcl-2, and decreased the protein expression levels of p-JAK2, STAT3, MDR1/ABCB1, MRP1/ABCC1, Survivin and Bcl-2, and conversely increased Bax expression. It also inhibited the proliferation, migration and invasion of U-2OS/Dox cells and promoted cells apoptosis. The results of STAT3 silencing experiments in the above indicators were consistent with that of miR-506-3p overexpression. Conclusion: Overexpression of miR-506-3p could inhibit the JAK2/STAT3 pathway and the malignant biological behaviors, then further reverse doxorubicin resistance in drug-resistant osteosarcoma cells. The study reported a new molecular mechanism for reversing the resistance of osteosarcoma to doxorubicin chemotherapy and provided theoretical support for solving the clinical problems of doxorubicin resistance in osteosarcoma.

Exosome-Transmitted miR-506-3p Inhibits Colorectal Cancer Cell Malignancy via Regulating GSTP1

Exosome-mediated microRNA transfer has been shown to regulate cancer progression. However, the involvement of exosomal-miR-506-3p in colorectal cancer (CRC) is unknown. The goal of the research was to study into the role of exosomal-miR-506-3p in CRC. Using a qRT-PCR experiment, it was observed that CRC tissues had lower levels of miR-506-3p than non-tumor tissues. It was observed that miR-506-3p inhibited the proliferation, regulates apoptosis, and cell cycle of HT29 and SW480 cells as compared to control groups. Dual luciferase reporter assay results showed that GSTP1 was the downstream target molecule of miR-506-3p, which was consistent with the database prediction. Furthermore, FHC cells transfected with miR-506-3p could transfer miR-506-3p to SW480 cells, limiting cell growth and inducing cell death. We discovered a unique regulatory mechanism in which exosome-mediated transfer of miR-506-3p reduces proliferation and induces apoptosis in CRC through negative regulation of GSTP1, implying that exosome-mediated delivery of miR-506-3p provides fresh insight into CRC diagnostics and treatment.

LncRNAs could play a vital role in osteosarcoma treatment: Inhibiting osteosarcoma progression and improving chemotherapy resistance

Osteosarcoma (OS) is one of the most common primary solid malignant tumors in orthopedics, and its main clinical treatments are surgery and chemotherapy. However, a wide surgical resection range, functional reconstruction of postoperative limbs, and chemotherapy resistance remain as challenges for patients and orthopedists. To address these problems, the discovery of new effective conservative treatments is important. Long non-coding RNAs (lncRNAs) are RNAs longer than 200 nucleotides in length that do not encode proteins. Researchers have recently found that long non-coding RNAs are closely associated with the development of OS, indicating their potentially vital role in new treatment methods for OS. This review presents new findings regarding the association of lncRNAs with OS and summarizes potential clinical applications of OS with lncRNAs, including the downregulation of oncogenic lncRNAs, upregulation of tumor suppressive lncRNAs, and lncRNAs-based treatment to improve chemotherapy resistance. We hope these potential methods will be translated into clinical applications and greatly reduce patient suffering.

LncRNA-miRNA axis in tumor progression and therapy response: An emphasis on molecular interactions and therapeutic interventions

Epigenetic factors are critical regulators of biological and pathological mechanisms and they could interact with different molecular pathways. Targeting epigenetic factors has been an idea approach in disease therapy, especially cancer. Accumulating evidence has highlighted function of long non-coding RNAs (lncRNAs) as epigenetic factors in cancer initiation and development and has focused on their association with downstream targets. microRNAs (miRNAs) are the most well-known targets of lncRNAs and present review focuses on lncRNA-miRNA axis in malignancy and therapy resistance of tumors. LncRNA-miRNA regulates cell death mechanisms such as apoptosis and autophagy in cancers. This axis affects tumor metastasis via regulating EMT and MMPs. Besides, lncRNA-miRNA axis determines sensitivity of tumor cells to chemotherapy, radiotherapy and immunotherapy. Based on the studies, lncRNAs can be affected by drugs and genetic tools in cancer therapy and this may affect expression level of miRNAs as their downstream targets, leading to cancer suppression/progression. LncRNAs have both tumor-promoting and tumor-suppressor functions in cancer and this unique function of lncRNAs has complicated their implication in tumor therapy. LncRNA-miRNA axis can also affect other signaling networks in cancer such as PI3K/Akt, STAT3, Wnt/β-catenin and EZH2 among others. Notably, lncRNA/miRNA axis can be considered as a signature for diagnosis and prognosis in cancers.

The role of long non-coding RNA FGD5-AS1 in cancer

Long noncoding RNAs (lncRNAs) refers to a class of RNAs that have at least 200 nucleotides and do not encode proteins, and the relationship between lncRNA and cancer has recently attracted considerable research attention. The lncRNA FGD5-AS1 is a newly discovered lncRNA with a length of 3772 nucleotides. Studies have found that FGD5-AS1 is abnormally highly expressed in many cancer tissues and was closely related to the lymph node metastasis, tumor invasion, survival time, and recurrence rate of various cancers. Mechanistic analyses show that FGD5-AS1 can stabilize mRNA expression by sponging miRNA, which not only induces cancer cell proliferation, metastasis, invasion, and chemoresistance in vitro, but also promotes tumor growth and metastasis in vivo. In addition, FGD5-AS1 can serve as a diagnostic or prognostic marker for a variety of cancers. This review demonstrates the clinical significance of FGD5-AS1 in human cancer and its role in tumorigenesis and tumor progression.

lncRNA FGD5-AS1 Regulates Bone Marrow Stem Cell Proliferation and Apoptosis by Affecting miR-296-5p/STAT3 Axis in Steroid-Induced Osteonecrosis of the Femoral Head

Background

Osteonecrosis of the femoral head (ONFH) is a common hip joint disease, which is more harmful and seriously affects the lives of patients. This study aims to clarify the regulatory mechanism of lncRNA FGD5-AS1 in ONFH.

Methods

The expression of the protein and mRNA was detected by RT-qPCR and Western blot assay. The regulatory mechanism of lncRNA FGD5-AS1 was detected by the dual-luciferase reporter assay, CCK-8 assay, and flow cytometry assay.

Results

Dex can inhibit cell proliferation and differentiation and induce apoptosis in hBMSCs in a dose-dependent manner. Overexpression of lncRNA FGD5-AS1 promoted cell proliferation and restrained apoptosis in Dex-treated hBMSCs. In addition, lncRNA FGD5-AS1 acts as a sponge for miR-296-5p. Also, miR-296-5p directly targets STAT3. More importantly, miR-296-5p and STAT3 can affect the function of lncRNA FGD5-AS1 in Dex-treated hBMSCs.

Conclusion

lncRNA FGD5-AS1 promotes cell proliferation and inhibits apoptosis in steroid-induced ONFH through acting as a sponge for miR-296-5p and upregulation of STAT3.

Targeting EGFR sensitizes 5-Fu-resistant colon cancer cells through modification of the lncRNA-FGD5-AS1-miR-330-3p-Hexokinase 2 axis

5-Fluorouracil (5-Fu) is a widely applied anti-cancer agent against colorectal cancer (CRC), yet a number of CRC patients have developed resistance to 5-Fu-based chemotherapy. The epidermal growth factor receptor (EGFR) is recognized as an oncogene that promotes diverse cancer progresses. In addition, long noncoding RNAs (lncRNAs) are essential regulators of cancers. Here we report that EGFR and lncRNA-FGD5-AS1 promoted 5-Fu resistance of CRC. By establishing the 5-Fu-resistant CRC cell line, we detected that EGFR, FGD5-AS1, and glucose metabolism were significantly elevated in 5-Fu-resistant CRC cells. A microRNA-microarray analysis revealed that miR-330-3p functions as a downstream effector of FGD5-AS1. FGD5-AS1 directly sponged miR-330-3p to form a competing endogenous RNA (ceRNA) network, leading to inhibition of miR-330-3p expression. Furthermore, bioinformatics analysis revealed that Hexokinase 2 (HK2) was a potential target of miR-330-3p, which was validated by luciferase assay. Rescue experiments demonstrated that FGD5-AS1 promotes glycolysis through modulating the miR-330-3p-HK2 axis, leading to 5-Fu resistance of CRC cancer cells. Finally, in vitro and in vivo xenograft experiments consistently demonstrated that inhibition of EGFR by the specific inhibitor erlotinib effectively enhanced the anti-tumor toxicity of 5-Fu by targeting the EGFR-FGD5-AS1-miR-330-3p-HK2 pathway. In summary, this study demonstrates new mechanisms of the EGFR-modulated 5-Fu resistance through modulating the noncoding RNA network, contributing to development of new approaches against chemoresistant CRC.

FGD5-AS1 facilitates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells via targeting the miR-506-3p/BMP7 axis

BACKGROUND

Osteoporosis is a systemic disease characterized by impaired bone formation, increased bone resorption, and brittle bone fractures. The osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) is considered to be a vital process for bone formation. Numerous studies have reported that long non-coding RNAs (lncRNAs) are involved in the osteogenic differentiation of hBMSCs. The present study aimed to investigate the effect of FGD5 antisense RNA 1 (FGD5-AS1) on osteogenic differentiation.

METHODS

RT-qPCR was performed to detect the expression of FGD5-AS1, miR-506-3p, and osteogenesis-related genes OCN, OPN, OSX, and RUNX2. Western blotting was carried out to detect the protein levels of osteogenesis-related markers. In addition, the regulatory effect of FGD5-AS1 on osteogenic differentiation was detected through alkaline phosphatase (ALP) activity, Alizarin Red S (ARS) staining, and Cell Counting Kit-8 (CCK-8). Bioinformatics analysis and luciferase reporter assay were used to predict and validate the interaction between FGD5-AS1 and miR-506-3p as well as miR-506-3p and bone morphogenetic protein 7 (BMP7).

RESULTS

The RT-qPCR analysis revealed that FGD5-AS1 was upregulated in hBMSCs following induction of osteogenic differentiation. In addition, FGD5-AS1 knockdown attenuated hBMSC viability and osteogenic differentiation. Bioinformatics analysis and luciferase reporter assays verified that FGD5-AS1 could directly interact with microRNA (miR)-506-3p. Furthermore, miR-506-3p could directly target the 3'-untranslated region (3'-UTR) of BMP7. Additionally, functional assays demonstrated that miR-506-3p silencing could restore the suppressive effect of FGD5-AS1 knockdown on osteogenic differentiation and viability of hBMSCs, and miR-506-3p could attenuate osteogenic differentiation via targeting BMP7.

CONCLUSIONS

Taken together, the results of the present study suggested that FGD5-AS1 could positively regulate the osteogenic differentiation of hBMSCs via targeting the miR-506-3p/BMP7 axis.

Long Non-Coding RNA FGD5-AS1 Induced by Chlamydia trachomatis Infection Inhibits Apoptosis via Wnt/β-Catenin Signaling Pathway

Background

Chlamydia trachomatis (Ct) is one of the most common bacterial sexually transmitted infection (STI) pathogens in the world, but the exact pathogenic mechanism still needs to be further elucidated. Long non-coding RNAs (lncRNAs) have become vital regulators in many biological processes. Their role in the interaction between Ct and host cells has not been reported.

Methods

Microarrays were used to study the expression profiles of lncRNAs and mRNAs in HeLa cells at 12, 24, and 40 h post-infection (hpi). Differentially expressed lncRNAs and mRNAs were verified by RT-qPCR. Coding-non-coding (CNC) network analysis showed co-expression molecules of selected lncRNA. Western blot, flow cytometry, and indirect immunofluorescence were used to detect the effect of lncRNA FGD5-AS1 on apoptosis during Ct infection.

Results

Compared with the uninfected group, the number of differential lncRNAs were 2,130, 1,081, and 1,101 at 12, 24, and 40 hpi, and the number of differential mRNAs was 1,998, 1,129, and 1,330, respectively. Ct induced differential expression of large amounts of lncRNAs and mRNAs in HeLa cells, indicating that lncRNAs may play roles in the pathogenesis of Ct. RT-qPCR verified six differential lncRNAs and six differential mRNAs, confirming the reliability of the microarray. Among these molecules, lncRNA FGD5-AS1 was found to be upregulated at 12 and 24 hpi. Coding-non-coding (CNC) network analysis showed that co-expressed differential molecules of FGD5-AS1 at 12 and 24 hpi were enriched in the DNA replication and Wnt signaling pathway. The downregulation of FGD5-AS1 decreased the expression of β-catenin and inhibited the translocation of β-catenin and the DNA replication, while it promoted apoptosis of the host cells.

Conclusions

DNA replication and apoptosis of host cells were affected by upregulating FGD5-AS1 via Wnt/β-catenin pathway during Ct infection. This study provides evidence that lncRNAs are involved in the coaction between Ct and hosts, and provides new insights into the study of lncRNAs that regulate chlamydial infection.

MicroRNA-506-3p inhibits colorectal cancer cell proliferation through targeting enhancer of zeste homologue 2

A large number of studies have shown that microRNA (miRNA) has an important relationship with the occurrence and development of colorectal cancer (CRC), but its specific molecular mechanism has not been fully elucidated. This study is to explore the influence of miR-506-3p on the malignant behavior of CRC and its underlying molecular mechanism. Our results show that miR-506-3p was lowly expressed and enhancer of zeste homologue 2 (EZH2) was highly expressed in CRC. Overexpressing miR-506-3p or silencing EZH2 inhibited CRC cell proliferation, migration and invasion and promoted apoptosis. Inhibiting miR-506-3p promoted CRC cell proliferation, migration and invasion but inhibited apoptosis. These impacts were reversed after co-transfecting si-EZH2. Further mechanism studies have shown that miR-506-3p can reduce EZH2 expression in CRC cells by binding to the 3ʹUTR end of EZH2. In summary, the results of this study show that miR-506-3p inhibited CRC progression through targeting EZH2 expression. This provides a new molecular target for the clinical treatment of CRC in the future.