Oncogenic ETS fusions promote DNA damage and proinflammatory responses via pericentromeric RNAs in extracellular vesicles.

Aberrant expression of the E26 transformation-specific (ETS) transcription factors characterizes numerous human malignancies. Many of these proteins, including EWS:FLI1 and EWS:ERG fusions in Ewing sarcoma (EwS) and TMPRSS2:ERG in prostate cancer (PCa), drive oncogenic programs via binding to GGAA repeats. We report here that both EWS:FLI1 and ERG bind and transcriptionally activate GGAA-rich pericentromeric heterochromatin. The respective pathogen-like HSAT2 and HSAT3 RNAs, together with LINE, SINE, ERV, and other repeat transcripts, are expressed in EwS and PCa tumors, secreted in extracellular vesicles (EVs), and are highly elevated in plasma of patients with EwS with metastatic disease. High human satellite 2 and 3 (HSAT2,3) levels in EWS:FLI1- or ERG-expressing cells and tumors were associated with induction of G2/M checkpoint, mitotic spindle, and DNA damage programs. These programs were also activated in EwS EV-treated fibroblasts, coincident with accumulation of HSAT2,3 RNAs, proinflammatory responses, mitotic defects, and senescence. Mechanistically, HSAT2,3-enriched cancer EVs induced cGAS-TBK1 innate immune signaling and formation of cytosolic granules positive for double-strand RNAs, RNA-DNA, and cGAS. Hence, aberrantly expressed ETS proteins derepress pericentromeric heterochromatin, yielding pathogenic RNAs that transmit genotoxic stress and inflammation to local and distant sites. Monitoring HSAT2,3 plasma levels and preventing their dissemination may thus improve therapeutic strategies and blood-based diagnostics.

EV-mediated intercellular communication in acute myeloid leukemia: Transport of genetic materials in the bone marrow microenvironment.

Acute myeloid leukemia (AML) is a common hematological cancer. Cancer cells exchange information with the surrounding microenvironment, which can be transmitted by extracellular vesicles (EVs). In recent years, the genetic materials transported by EVs have attracted attention due to their important roles in different pathological processes. EV-derived ncRNAs (EV-ncRNAs) regulate physiological functions and maintain homeostasis, mainly including microRNAs, long noncoding RNAs, and circular RNAs. However, the mechanism of involvement and potential clinical application of EV-ncRNAs in AML have not been reported. Given the unique importance of the bone marrow microenvironment (BMME) for AML, a greater understanding of the communication between leukemic cells and the BMME is needed to improve the prognosis of patients and reduce the incidence of recurrence. Additionally, studies on leukemic EV-ncRNA transport guide the design of new diagnostic and therapeutic tools for AML. This review systematically describes intercellular communication in the BMME of AML and emphasizes the role of EVs. More importantly, we focus on the information transmission of EV-ncRNAs in the BMME to explore their clinical application as potential biomarkers and therapeutic targets.

Cromolyn chitosan nanoparticles reverse the DNA methylation of RASSF1A and p16 genes and mitigate DNMT1 and METTL3 expression in breast cancer cell line and tumor xenograft model in mice.

BACKGROUND: Developing epigenetic drugs for breast cancer (BC) remains a novel therapeutic approach. Cromolyn is a mast cell stabilizer emerging as an anticancer drug; its encapsulation in chitosan nanoparticles (CSNPs) improves its effect and bioavailability. However, its effect on DNA and RNA methylation machineries has not been previously tackled. METHODS: The possible anticancer effect of cromolyn CSNPs and its potential as an epigenetic drug was investigated in vitro using MCF-7 human BC cell line and in vivo using Ehrlich ascites carcinoma-xenograft model in mice symbolizing murine mammary adenocarcinoma. Mice were injected with a single dose of Ehrlich ascites carcinoma cells subcutaneously for the induction of tumor mass, and then randomized into three groups: control, cromolyn CSNPs (equivalent to 5 mg cromolyn/kg, i.p.) and plain CSNPs twice/week for 2 weeks. RESULTS: Cromolyn CSNPs showed prominent anticancer effect in MCF-7 cells by reducing the cell viability percent and enhancing DNA damage in the comet assay demonstrating its apoptotic actions. Mechanistically, cromolyn CSNPs influenced potential epigenetic processes through mitigating DNA methyltransferase 1 (DNMT1) expression, reversing the hypermethylation pattern of the tumor suppressor RASSF1A and p16 genes and attenuating the expression of the RNA N6-methyladenosine writer, methyltransferase-like 3 (METTL3). Cromolyn CSNPs diminished ERK1/2 phosphorylation, a possible arm influencing DNMT1 expression. In vivo, cromolyn CSNPs lessened the tumor volume and halted DNMT1 and METTL3 expression in Ehrlich carcinoma mice. CONCLUSIONS: Cromolyn CSNPs have the premise as an epigenetic drug through inhibiting ERK1/2 phosphorylation/DNMT1/DNA methylation and possibly impacting the RNA methylation machinery via mitigating METTL3 expression.

LINC01116 Promotes Migration and Invasion of Oral Squamous Cell Carcinoma by Acting as a Competed Endogenous RNA in Regulation of MMP1 Expression.

Oral squamous cell carcinoma (OSCC) has increasingly become a worldwide health concern, and its survival rate has not been much improved partially due to a deficiency of precise molecular markers. Dysregulation of LINC01116, a long noncoding RNA sequence, has been observed in several types of cancer. However, the role played by LINC01116 in OSCC has not yet been fully elaborated. This study explored how LINC01116 was involved in the regulation of OSCC progression by analyzing expressions of LINC01116 in OSCC patients. The findings demonstrated upregulation of LINC01116 in OSCC tissues as opposed to regular oral mucosa, and overexpression of LINC01116 was correlated with advanced tumor status. LINC01116 knockdown using shRNA markedly reduced the OSCC cell invasion and migration in vitro. Moreover, the expression of LINC01116 was negatively correlated with that of microRNA-9-5p (miR-9). Luciferase reporter and loss-of-function assays demonstrated that LINC01116 functioned as a competing endogenous RNA (ceRNA) that could effectively sponge miR-9, thus regulating the derepression of matrix metalloproteinase 1 (MMP1). Furthermore, we confirmed that LINC01116 knockdown did not affect the expression of MMP1 messenger RNA (mRNA). Collectively, it is demonstrated in this study that overexpression of LINC01116 can promote the OSCC progression. The LINC01116-miR-9-MMP1 axis provides a novel insight into the OSCC pathogenesis and offers potential therapeutic targets against OSCC.

Analyses of human cancer driver genes uncovers evolutionarily conserved RNA structural elements involved in posttranscriptional control.

Experimental breakthroughs have provided unprecedented insights into the genes involved in cancer. The identification of such cancer driver genes is a major step in gaining a fuller understanding of oncogenesis and provides novel lists of potential therapeutic targets. A key area that requires additional study is the posttranscriptional control mechanisms at work in cancer driver genes. This is important not only for basic insights into the biology of cancer, but also to advance new therapeutic modalities that target RNA-an emerging field with great promise toward the treatment of various cancers. In the current study we performed an in silico analysis on the transcripts associated with 800 cancer driver genes (10,390 unique transcripts) that identified 179,190 secondary structural motifs with evidence of evolutionarily ordered structures with unusual thermodynamic stability. Narrowing to one transcript per gene, 35,426 predicted structures were subjected to phylogenetic comparisons of sequence and structural conservation. This identified 7,001 RNA secondary structures embedded in transcripts with evidence of covariation between paired sites, supporting structure models and suggesting functional significance. A select set of seven structures were tested in vitro for their ability to regulate gene expression; all were found to have significant effects. These results indicate potentially widespread roles for RNA structure in posttranscriptional control of human cancer driver genes.

miR-182 targeting reprograms tumor-associated macrophages and limits breast cancer progression.

The protumor roles of alternatively activated (M2) tumor-associated macrophages (TAMs) have been well established, and macrophage reprogramming is an important therapeutic goal. However, the mechanisms of TAM polarization remain incompletely understood, and effective strategies for macrophage targeting are lacking. Here, we show that miR-182 in macrophages mediates tumor-induced M2 polarization and can be targeted for therapeutic macrophage reprogramming. Constitutive miR-182 knockout in host mice and conditional knockout in macrophages impair M2-like TAMs and breast tumor development. Targeted depletion of macrophages in mice blocks the effect of miR-182 deficiency in tumor progression while reconstitution of miR-182-expressing macrophages promotes tumor growth. Mechanistically, cancer cells induce miR-182 expression in macrophages by TGFß signaling, and miR-182 directly suppresses TLR4, leading to NFκb inactivation and M2 polarization of TAMs. Importantly, therapeutic delivery of antagomiR-182 with cationized mannan-modified extracellular vesicles effectively targets macrophages, leading to miR-182 inhibition, macrophage reprogramming, and tumor suppression in multiple breast cancer models of mice. Overall, our findings reveal a crucial TGFß/miR-182/TLR4 axis for TAM polarization and provide rationale for RNA-based therapeutics of TAM targeting in cancer.

Nuclear genome-derived circular RNA circPUM1 localizes in mitochondria and regulates oxidative phosphorylation in esophageal squamous cell carcinoma.

Circular RNAs (circRNAs) were shown to play an important role in the occurrence and progression of tumors. However, the functions of nuclear genome-derived circRNAs localized in mitochondria of tumor cells remain largely elusive. Here, we report that circPUM1, a circular RNA derived from back-splicing of pre-mRNAs of nuclear genome PUM1, localizes in mitochondria. The expression level of circPUM1 is positively correlated with HIF1α accumulation under CoCl2-induced intracellular hypoxic-like condition in esophageal squamous cell carcinoma (ESCC) cell lines. Importantly, circPUM1 acts as a scaffold for the interaction between UQCRC1 and UQCRC2 in ESCC cell lines. Knock-down of circPUM1 would result in lower intracellular oxygen concentration, downregulated oxidative phosphorylation, decrease of mitochondrial membrane potential, increase of ROS generation and shrinking of mitochondria, respectively. CircPUM1 depletion induces dysfunction of the mitochondrial complex III and the cleavage of caspase3 spontaneously. Interestingly, disruption of circPUM1 led to pyroptosis that initiates the cell death of ESCC cell lines. Therefore, we conclude that circPUM1 plays a critical role in maintaining the stability of mitochondrial complex III to enhance oxidative phosphorylation for ATP production of ESCC cells and moreover propose that ESCC cells exploit circPUM1 during cell adaptation.

Exosome-derived miR-200a promotes esophageal cancer cell proliferation and migration via the mediating Keap1 expression.

Previous studies have reported that exosomes bearing certain microRNAs (miRNAs) are related to the physiological functions of different types of cancer cells. Our study aimed to elucidate the role of miR-200a in esophageal squamous cell carcinoma (ESCC). We observed that miR-200a expression is higher in esophageal carcinoma cells, tissues, and exosomes than in normal cells and healthy tissues. We showed that exosome-shuttled miR-200a promotes the proliferation, migration, and invasion of esophageal cells and inhibits apoptosis, thereby leading to the progression of ESCC. We showed that miR-200a exerts its effects through its interaction with Keap1, thus altering the Keap1/Nrf2 signaling pathway. Our results suggest that exosome-shuttled miR-200a might be useful as a biomarker for prognosis in patients with ESCC.

The Role of Exosomal Non-Coding RNAs in Colorectal Cancer Drug Resistance.

BACKGROUND: Colorectal cancer (CRC) is one of the most common types of cancer diagnosed worldwide with high morbidity; drug resistance is often responsible for treatment failure in CRC. Non-coding RNAs (ncRNAs) play distinct regulatory roles in tumorigenesis, cancer progression and chemoresistance. METHODS: A literature search was conducted in PubMed database in order to sum up and discuss the role of exosomal ncRNAs (ex-ncRNAs) in CRC drug resistance/response and their possible mechanisms. RESULTS: Thirty-six (36) original research articles were identified; these included exosome or extracellular vesicle (EV)-containing microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and small-interfering (siRNAs). No studies were found for piwi-interacting RNAs. CONCLUSIONS: Exosomal transfer of ncRNAs has been documented as a new mechanism of CRC drug resistance. Despite being in its infancy, it has emerged as a promising field for research in order to (i) discover novel biomarkers for therapy monitoring and/or (ii) reverse drug desensitization.

lncRNA GAS5 Sensitizes Breast Cancer Cells to Ionizing Radiation by Inhibiting DNA Repair.

Radioresistance of breast cancer is a major reason for therapeutic failure and limits further increases in the dose of radiation due to severe adverse effects. Recently, long noncoding RNAs (lncRNAs) have been shown to regulate cancer proliferation, chemoresistance, and radioresistance. Among these lncRNAs, lncRNA GAS5 expression was shown to be downregulated in breast cancer and related to trastuzumab resistance. However, its role in the radiation response is unclear. In this study, we demonstrated that lncRNA GAS5 expression was reduced in irradiated cells and that overexpression of GAS5 reduced cell viability and promoted cell apoptosis after irradiation. Moreover, overexpression of GAS5 resulted in increased G2/M arrest and unrepaired DNA damage, indicating a radiosensitizing role of GAS5 in breast cancer cells. Finally, we found that a GAS5-interacting miRNA, miR-21, reversed the radiosensitizing effects of GAS5 by inhibiting the apoptotic pathway. In conclusion, we found that lncRNA GAS5 sensitized breast cancer cells to ionizing radiation by inhibiting DNA repair and suppressing miR-21, identifying novel targets for breast cancer radiosensitization.

Novel long non-coding RNA lncAMPC downregulates PTEN via miR-214 to promote nasopharyngeal carcinoma progression.

Long non-coding RNAs (lncRNAs) are a type of non-coding RNAs with transcript lengths exceeding 200 nt. lncRNAs suppress or promote cancer mainly by regulating gene expression. The aim of this study was to explore the role of lncRNAs activated in metastatic PCa (lncAMPC) in nasopharyngeal carcinoma (NPC). Total RNAs were isolated from NPC and adjacent non-tumor tissues from 60 NPC patients and subjected to RT-qPCR to analyze differential expression of lncAMPC and miR-214. The roles of lncAMPC and miR-214 in regulating PTEN expression were analyzed using RT-qPCR and Western blot. Cell proliferation was analyzed using the BrdU assay. The results showed that lncAMPC was overexpressed in NPC tissues and was localized in both nuclei and cytoplasms of NPC cells. MiR-214 was positively correlated with lncAMPC. LncAMPC overexpression upregulated miR-214 and indirectly downregulated PTEN via miR-214. BrdU incorporation assay showed that lncAMPC and miR-214 overexpression increased cell proliferation. PTEN overexpression completely reversed the promoting effects of lncAMPC and miR-214 overexpression on cell proliferation. Therefore, lncAMPC might downregulate PTEN via miR-214 to increase NPC cell proliferation.

MicroRNA MiR-490-5p suppresses pancreatic cancer through regulating epithelial-mesenchymal transition via targeting MAGI2 antisense RNA 3.

Pancreatic cancer with about 5% five-year overall survival rate remains a challenge. Invasion and migration of pancreatic cancer cells are the main factors leading to poor prognosis. MicroRNA-490-5p (miR-490-5p) has anti-cancer effects in a variety of tumors, but its role in pancreatic cancer has not been reported. The mRNA expressions of miR-490-5p, MAGI2 antisense RNA 3 (MAGI2-AS3), Matrix metalloproteinase (MMP)2, MMP9, N-cadherin, and E-cadherin were detected by quantitative real-time PCR, while the protein expressions of these genes except miR-490-5p were measured by Western blot analysis. The cell viability, apoptosis, migration and invasion were detected by cell counting kit-8 (CCK-8), apoptosis and transwell assays. MiR-490-5p was abnormally low-expressed in pancreatic cancer, whose down-regulation generated enhanced effects on viability, migration and invasion in pancreatic cancer cells, as well as MAGI2-AS3 expression. MiR-490-5p mimic exerted the opposite effect on cells, which also down-regulated MMP2, MMP9, and N-cadherin protein expressions, while up-regulating E-cadherin protein expression. MAGI2-AS3, which was the targeted binding site of miR-490-5p, promoted viability, migration and invasion, and inhibited apoptosis of cancer cells. More importantly, miR-490-5p played an anti-cancer role in pancreatic cancer by targeting MAGI2-AS3 and regulating epithelial-mesenchymal transition (EMT), which was partially offset by MAGI2-AS3.

P. aeruginosa augments irradiation injury via 15-lipoxygenase-catalyzed generation of 15-HpETE-PE and induction of theft-ferroptosis.

Total body irradiation (TBI) targets sensitive bone marrow hematopoietic cells and gut epithelial cells, causing their death and inducing a state of immunodeficiency combined with intestinal dysbiosis and nonproductive immune responses. We found enhanced Pseudomonas aeruginosa (PAO1) colonization of the gut leading to host cell death and strikingly decreased survival of irradiated mice. The PAO1-driven pathogenic mechanism includes theft-ferroptosis realized via (a) curbing of the host antiferroptotic system, GSH/GPx4, and (b) employing bacterial 15-lipoxygenase to generate proferroptotic signal - 15-hydroperoxy-arachidonoyl-PE (15-HpETE-PE) - in the intestines of irradiated and PAO1-infected mice. Global redox phospholipidomics of the ileum revealed that lysophospholipids and oxidized phospholipids, particularly oxidized phosphatidylethanolamine (PEox), represented the major factors that contributed to the pathogenic changes induced by total body irradiation and infection by PAO1. A lipoxygenase inhibitor, baicalein, significantly attenuated animal lethality, PAO1 colonization, intestinal epithelial cell death, and generation of ferroptotic PEox signals. Opportunistic PAO1 mechanisms included stimulation of the antiinflammatory lipoxin A4, production and suppression of the proinflammatory hepoxilin A3, and leukotriene B4. Unearthing complex PAO1 pathogenic/virulence mechanisms, including effects on the host anti/proinflammatory responses, lipid metabolism, and ferroptotic cell death, points toward potentially new therapeutic and radiomitigative targets.

LncRNA PVT1 facilitates DLBCL development via miR-34b-5p/Foxp1 pathway.

Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of non-Hodgkin lymphoma and is a very aggressive malignancy with tumor growing rapidly in organs like lymph nodes. The pathogenesis of DLBCL is not clear and the prognosis of DLBCL requires improvement. Here, we investigated the mechanisms of DLBCL, with the focus on lncRNA PVT1/miR-34b-5p/Foxp1 axis. Human DLBCL tissues from diagnosed DLBCL patients and four human DLBCL cell lines, one normal human B lymphoblastoid cell line were used. qRT-PCR and western blotting were employed to measure expression levels of lncRNA PVT1, Foxp1, miR-34b-5p, ß-catenin, and proliferation-related proteins. MTT assay and colony formation assay were performed to determine cell proliferation. Flow cytometry was used to examine cell apoptosis. ChIP and Dual-luciferase assay were utilized to validate interactions of Foxp1/promoters, PVT1/miR-34b-5p and miR-34b-5p/Foxp1. Mouse tumor xenograft model was used to determine the effect of sh-PVT1 on tumor growth in vivo. In this study, we found PVT1 and Foxp1 were elevated in DLBCL tissues and cells while miR-34b-5p was decreased. Knockdown of PVT1, overexpression of miR-34b-5p, or Foxp1 knockdown repressed DLBCL cell proliferation but enhanced cell apoptosis. PVT1 directly bound miR-34b-5p to disinhibit Foxp1/ß-catenin signaling. Foxp1 regulated CDK4, CyclinD1, and p53 expression via binding with their promoters. Knockdown of Foxp1 partially reversed the effects of miR-34b-5p inhibitor on DLBCL cell proliferation and apoptosis. Inhibition of PVT1 through shRNA suppressed DLBCL tumor growth in vivo. All in all, lncRNA PVT1 promotes DLBCL progression via acting as a miR-34b-5p sponge to disinhibit Foxp1/ß-catenin signaling.

LncRNAs LCETRL3 and LCETRL4 at chromosome 4q12 diminish EGFR-TKIs efficiency in NSCLC through stabilizing TDP43 and EIF2S1.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are effective targeted therapy drugs for advanced non-small cell lung cancer (NSCLC) patients carrying sensitized EGFR mutations. The rapid development of EGFR-TKIs resistance represents a major clinical challenge for managing NSCLC. The chromosome 4q12 is the first genome-wide association study (GWAS)-reported locus associated with progression-free survival (PFS) of NSCLC patients treated with EGFR-TKIs. However, the biological significance of the noncoding transcripts at 4q12 in NSCLC remains elusive. In the present study, we identified two 4q12 long noncoding RNAs (lncRNAs) LCETRL3 and LCETRL4 which could significantly dimmish EGFR-TKIs efficiency. In line with their oncogenic role, evidently higher LCETRL3 and LCETRL4 levels were observed in NSCLC tissues as compared with normal specimens. Importantly, lncRNA LCETRL3 can interact with oncoprotein TDP43 and inhibit ubiquitination and degradation of TDP43. Similarly, lncRNA LCETRL4 can bind and stabilize oncoprotein EIF2S1 through reducing ubiquitin-proteasome degradation of EIF2S1. In particular, elevated levels of LCETRL3 or LCETRL4 in NSCLC cells resulted in stabilization of TDP43 or EIF2S1, increased levels of NOTCH1 or phosphorylated PDK1, activated AKT signaling and, thus, EGFR-TKIs resistance. Taken together, our data revealed a novel model that integrates two lncRNAs transcribed from the 4q12 locus into the regulation of EGFR-TKIs resistance in NSCLC. These findings shed new light on the importance of functionally annotating lncRNAs in the GWAS loci and provided insights to declare novel druggable targets, i.e., lncRNAs, which may unlock the therapeutic potential of EGFR-TKIs resistant NSCLC in the clinic.

Noncoding RNAs and hyperthermic intraperitoneal chemotherapy in advanced gastric cancer.

Gastric cancer (GC) is one of the most common malignant tumors globally. About 20-30% of patients with gastric cancer show peritoneal implantation metastasis at the first diagnosis. Peritoneal metastasis is responsible for 70% of deaths of patients with advanced gastric cancer. Although there are many ways to treat advanced gastric cancer, the prognosis of patients with recurrence is unsatisfactory. An auxiliary treatment with hyperthermic intraperitoneal chemotherapy (HIPEC), is an internationally recognized recommended treatment for advanced gastric cancer. A series of clinical trials have shown that HIPEC significantly improves the overall survival of patients with cancer. Compared with the cytoreductive surgery (CRS) alone, HIPEC combined with CRS markedly reduced the rate of peritoneal metastasis in patients with ovarian cancer and colorectal cancer. It has been demonstrated that HIPEC alters transcription of many genes by affecting non-coding RNAs, which may contribute to the suppressive effect of HIPEC on the synthesis of nucleic acids and proteins in cancer cells. This paper reviews the recent advances in understanding the role of non-coding RNAs in tumor invasion and metastasis of advanced gastric cancer. We also consider changes in noncoding RNA levels and other molecules in advanced gastric cancer cases treated with HIPEC. We hope that our review will provide a reference for future research on molecular epidemiology and etiology of advanced gastric cancer and promote precise treatment of this malignancy using HIPEC.

Processing body (P-body) and its mediators in cancer.

In recent years, processing bodies (P-bodies) formed by liquid-liquid phase separation, have attracted growing scientific attention due to their involvement in numerous cellular activities, including the regulation of mRNAs decay or storage. These cytoplasmic dynamic membraneless granules contain mRNA storage and decay components such as deadenylase and decapping factors. In addition, different mRNA metabolic regulators, including m6A readers and gene-mediated miRNA-silencing, are also associated with such P-bodies. Cancerous cells may profit from these mRNA decay shredders by up-regulating the expression level of oncogenes and down-regulating tumor suppressor genes. The main challenges of cancer treatment are drug resistance, metastasis, and cancer relapse likely associated with cancer stem cells, heterogeneity, and plasticity features of different tumors. The mRNA metabolic regulators based on P-bodies play a great role in cancer development and progression. The dysregulation of P-bodies mediators affects mRNA metabolism. However, less is known about the relationship between P-bodies mediators and cancerous behavior. The current review summarizes the recent studies on P-bodies mediators, their contribution to tumor development, and their potential in the clinical setting, particularly highlighting the P-bodies as potential drug-carriers such as exosomes to anticancer in the future.

Homo sapiens circular RNA 0003602 (Hsa_circ_0003602) accelerates the tumorigenicity of acute myeloid leukemia by modulating miR-502-5p/IGF1R axis.

Acute myeloid leukemia (AML) has become a worldwide malignant cancer. We intended to investigate the critical roles and mechanism underlying homo sapiens circular RNA 0003602 (hsa_circ_0003602) in AML progression, especially in tumor cell proliferation, migration, invasion, and apoptosis. Real-time PCR was applied to identify the differential expression of hsa_circ_0003602 and miR-502-5p in AML bone marrow tissues and cell lines. In addition, western blot analysis was employed to determine the levels insulin-like growth factor 1 receptor (IGF1R) protein. The biological behaviors were assessed by CCK-8 cell viability assay, flow cytometry assay for apoptosis detection, and Transwell migration and invasion assay. The relationships between target miRNA and downstream mRNA were investigated by bioinformatics, luciferase reporter assay, and biotin-labeled RNA pull-down assay. Hsa_circ_0003602 was upregulated and predicted poor survival in AML. Knockdown of hsa_circ_0003602 in AML cell lines induced the inhibition of proliferation, migration, and invasion and caused apoptosis. Hsa_circ_0003602 sequestered miR-502-5p by functioning as a competitive endogenous RNA (ceRNA), thereby regulating IGF1R expression. Hsa_circ_0003602 acted as a tumor promoter in AML via miR-502-5p/IGF1R axis. Our study provides evidence that hsa_circ_0003602, miR-502-5p, and IGF1R might form a regulatory axis to affect the carcinogenicity of AML cells and provide potential targets for the treatment of AML.

Long noncoding RNA ADIRF antisense RNA 1 upregulates insulin receptor substrate 1 to decrease the aggressiveness of osteosarcoma by sponging microRNA-761.

An increasing number of studies have supported the critical regulatory actions of long noncoding RNAs (lncRNAs) in osteosarcoma (OS). However, the detailed roles of adipogenesis regulatory factor-antisense RNA 1 (ADIRF-AS1) in OS have not been comprehensively described. Hence, we first detected ADIRF-AS1 expression in OS and evaluated its clinical significance. Functional experiments were then performed to determine the modulatory role of ADIRF-AS1 in OS progression. ADIRF-AS1 was found to be overexpressed in OS, and the overall survival of patients with OS who had high ADIRF-AS1 levels was shorter than that of those with low levels. ADIRF-AS1 knockdown led to restricted proliferation, migration, and invasiveness of OS cells and increased apoptosis. Additionally, ADIRF-AS1 downregulation impeded tumor growth in vivo. Mechanistically, ADIRF-AS1 acted as a competitive endogenous RNA for microRNA-761 (miR-761) that siphoned miR-761 away from its target, namely insulin receptor substrate 1 (IRS1), leading to IRS1 overexpression. Rescue experiments showed that low levels of miR-761 or restoration of IRS1 could neutralize the effects of ADIRF-AS1 ablation in OS cells. In summary, ADIRF-AS1 exacerbates the oncogenicity of the OS cells by targeting the miR-761/IRS1 axis. Our findings may aid in the advancement of lncRNA-directed therapeutics for OS.

High expression of small nucleolar RNA host gene 3 predicts poor prognosis and promotes bone metastasis in prostate cancer by activating transforming growth factor-beta signaling.

Bone metastasis is closely related to tumor death in prostate cancer (PC). Long noncoding RNA small nucleolar RNA host gene 3 (SNHG3) has been implicated in the initiation and progression of multiple human cancers. Nevertheless, the biological function of SNHG3 in PC has not been elucidated. Our results indicated that SNHG3 was upregulated in bone metastasis-positive PC tissues compared to bone metastasis-negative PC tissues and adjacent normal tissues. High expression of SNHG3 indicates advanced clinicopathological features and predicts poor prognosis in patients with PC. Meanwhile, SNHG3 knockdown suppressed the proliferation, migration, and invasion abilities of PC cells and inhibited PC cell metastasis to the bone. Mechanistically, SNHG3 enhanced the expression of transforming growth factor beta receptor 1 (TGFBR1) and activated transforming growth factor-Beta (TGF-ß) signaling by targeting miR-214-3p. Our study demonstrated the novel role of the SNHG3/miR-214-3p/TGF-ß axis in tumor growth and bone metastasis in PC, indicating that SNHG3 may act as a biomarker and promising therapeutic target against PC.