SiRNA-circFARSA-loaded porous silicon nanomaterials for pancreatic cancer treatment via inhibition of CircFARSA expression.

Novel functions and involvement of circFARSA have not been reported in pancreatic cancer; in addition, its inhibitor screening has not yet been conducted. The purpose of this study was to (1) verify circFARSA as a novel anti-cancer target for pancreatic cancer and (2) to prepare a novel anti-pancreatic cancer agent targeting circFARSA. In this study, we designed and synthesized a small interfering RNA (siRNA, named siRNA-circFARSA), which specifically inhibits circFARSA expression. Using liposomes and porous silicon nanoparticles (pSiNPs) as siRNA delivery system, we prepared liposome-siRNA-circFARSA and pSiNP-PEI-siRNA-circFARSA and investigated their anti-cancer mechanism by quantitative real-time PCR and western blotting. Cell proliferation curves and transwell migration assays were performed to investigate the effect of siRNAs proliferation and migration capabilities of cancer cells. Patient-derived tumor xenograft mouse models were used to investigate the anti-cancer effects in vivo. The data showed that both liposome-siRNA-circFARSA and pSiNP-PEI-siRNA-circFARSA (Si: 0.7 µg/mL) significantly inhibited the proliferation and migration of pancreatic cancer cells in vitro. However, the biological safety and in vivo anti-cancer effects of pSiNP-PEI-siRNA-circFARSA (Si: 22.4 µg/mL) were higher than those of liposome-siRNA-circFARSA. The results showed that siRNA-circFARSA could inhibit the expression of circFARSA and then BCL-2 protein expression, thereby leading to pancreatic cancer cell apoptosis after transportation into pancreatic cancer cells. Therefore, this study provides tools for pancreatic cancer treatment in the future, as it (1) verified circFARSA as a novel target for pancreatic cancer treatment, and (2) prepared a novel anti-pancreatic cancer agent (pSiNP-PEI-siRNA-circFARSA).

Circular RNA CCDC66 Improves Murine Double Minute 4 (MDM4) Expression through Targeting miR-370 in Colorectal Cancer.

INTRODUCTION: Colorectal cancer (CRC), a common digestive tract tumor that contains colon and rectal cancer, is one of the three most common cancers globally. circRNAs are involved in the occurrence and development of CRC, but the mechanism of how they participate in this process remains unclear. METHODS: We adopted PCR for expression measure, CCK-8 for cell proliferation detection, Transwell for cell migration and invasion detection, and dual-luciferase reporter assays to detect the potential downstream targets of CCDC66 in CRC. RESULTS: This study showed that circRNA CCDC66 was overexpressed in CRC tissues, and after knockdown, it inhibited the proliferation, migration, and invasion of CRC cells (RKO and HCT-116) in vitro. In addition, the dual-luciferase reporter assay showed that there was a binding site between circCCDC66 and miR-370, as well as between miR-370 and murine double minute 4 (MDM4). That is, circCCDC66 upregulated the expression of MDM4 through competitively binding to miR-370. The expression of circCCDC66 in CRC tissues was positively correlated with MDM4 and negatively correlated with miR-370. CONCLUSION: In summary, our results indicate that circCCDC66 is a key upregulation of CRC. circCCDC66 upregulates MDM4 through competitive binding to miR-370, thereby enhancing the metastatic ability of CRC cells and promoting the development of CRC.

Blocking hsa_circ_0074027 suppressed non-small cell lung cancer chemoresistance via the miR-379-5p/IGF1 axis.

Cancer cell chemoresistance is the primary reason behind cancer treatment failure. Previous reports suggest that circular RNA (circRNA) hsa_circ_0074027 (HC0074027) is a crucial modulator of non-small cell lung cancer (NSCLC) disease progression. Herein, we delineated the underlying mechanism of HC0074027-regulated chemoresistance in NSCLC. We employed quantitative real-time polymerase chain reaction (qRT-PCR) or Elisa in the detection of HC0074027, micoRNA-379-5p (miR-379-5p), and insuline-like growth factor I (IGF1) expressions. Cell survival was evaluated via the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Direct associations among HC0074027, miR-379-5p, and IGF1 were examined via dual-luciferase reporter (DLR) and RNA immunoprecipitation (RIP) assays. Lastly, HC0074027 was incorporated into nude mice to examine its biological activity in vivo. Based on our analysis, HC0074027 levels strongly correlated with NSCLC chemoresistance to docetaxel (DTX), cisplatin (DDP), and paclitaxel (PTX). Alternately, HC0074027 silencing enhanced chemosensitivity in vitro. In vivo, HC0074027 downregulation suppressed tumor expansion and increased cancer cell sensitivity to chemotherapy. We also revealed that HC0074027 physically interacts with miR-379-5p to exert its biological function in vitro. Moreover, IGF1 is a functionally crucial target of miR-379-5p in modulating NSCLC chemoresistance in vitro. Finally, we demonstrated that HC0074027 can indirectly modulate IGF1 levels via sequestering miR-379-5p. We demonstrated that HC0074027 promotes NSCLC chemoresistance via sequestering miR-379-5p activity, and modulating IGF1 expression. Our work highlights the significance of HC0074027 in NSCLC chemoresistance and suggests HC0074027 to be an excellent candidate for targeted NSCLC therapy.

Circular RNA hsa_circ_0091579 facilitates the Warburg effect and malignancy of hepatocellular carcinoma cells via the miR-624/H3F3B axis.

BACKGROUND: Hepatocellular carcinoma (HCC) is a primary liver cancer with a high mortality rate. It has been reported that circular RNA hsa_circ_0091579 (circ_0091579) is involved in HCC progression. Nevertheless, the molecular mechanism by which circ_0091579 modulates HCC advancement is indistinct. METHODS: The expression of circ_0091579, microRNA (miR)-624, and H3 histone family member 3B (H3F3B) mRNA was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of HCC cells were analyzed using an extracellular flux analyzer. Adenosine triphosphate (ATP) level was evaluated using a commercial kit. Cell migration, invasion, and apoptosis were assessed by wound-healing, transwell, or flow cytometry assay. The relationship between miR-624 and circ_0091579 or H3F3B was verified using luciferase reporter assay and/or RNA immunoprecipitation (RIP) assay. H3F3B protein level was detected by western blotting. RESULTS: Circ_0091579 was upregulated in HCC tissues and cells. Circ_0091579 inhibition decreased xenograft tumor growth in vivo and repressed Warburg effect, migration, invasion, and induced apoptosis of HCC cells in vitro. MiR-624 was downregulated, while H3F3B was upregulated in HCC tissues and cells. Circ_0091579 acted as a miR-624 sponge and regulated H3F3B expression by adsorbing miR-624. MiR-624 inhibitor reversed circ_0091579 downregulation-mediated effects on the Warburg effect and malignant behaviors of HCC cells. H3F3B overexpression reversed the repressive impact of miR-624 mimic on the Warburg effect and malignancy of HCC cells. CONCLUSIONS: Circ_0091579 accelerated Warburg effect and tumor growth via upregulating H3F3B via adsorbing miR-624 in HCC, providing evidence to support the involvement of circ_0091579 in the progression of HCC.

Hsa_circ_0069094 knockdown inhibits cell proliferation, migration, invasion and glycolysis, while induces cell apoptosis by miR-661/HMGA1 axis in breast cancer.

Circular RNAs (circRNAs) are revealed to regulate breast cancer progression. This study aimed to investigate hsa_circ_0069094-mediated effects on breast cancer cell malignancy. Quantitative real time PCR was employed to evaluate the expressions of hsa_circ_0069094, miR-661 and high mobility group A1 (HMGA1). Western blot was performed to determine the protein expression of HMGA1 and proliferating cell nuclear antigen. Breast cancer malignant progressions were explained by cell counting kit-8 proliferation, cell colony formation, flow cytometry analysis, wound-healing and transwell assays. Cell glycolysis was assessed by detecting glucose take, lactate production and hexokinase 2 (HK2) protein level. The target relationship between miR-661 and hsa_circ_0069094 or HMGA1 was predicted by circular RNA interactome and targetscan online databases, and identified by dual-luciferase reporter and RNA immunoprecipitation assay. The effects of hsa_circ_0069094 knockdown on breast cancer growth in vivo were elucidated by in vivo tumor formation assay. Hsa_circ_0069094 and HMGA1 expression were significantly upregulated, while miR-661 expression level was downregulated in breast cancer tissues and cells relative to adjacent normal breast tissues or MCF-10A cells. Functionally, hsa_circ_0069094 knockdown inhibited cell glycolysis, proliferation, migration and invasion, whereas induced cell apoptosis in breast cancer, which was decreased by miR-661 inhibitor. Mechanistically, hsa_circ_0069094 regulated HMGA1 by sponging miR-661. Furthermore, hsa_circ_0069094 knockdown repressed tumor formation in vivo. Collectively, hsa_circ_0069094 knockdown repressed breast cancer cell carcinogenesis and cell glycolysis by regulating HMGA1 through sponging miR-661, which provided a new insight for studying the mechanism of hsa_circ_0069094 in modulating breast cancer development.

Upregulated hsa_circRNA_100269 inhibits the growth and metastasis of gastric cancer through inactivating PI3K/Akt axis.

The pathogenesis of GC involves the complex networking of multiple signaling pathways; however, the detailed mechanisms of tumorigenesis of GC remains largely unknown. Therefore, it is necessary to explore novel diagnostic/prognostic biomarkers for GC. In this study, the levels of hsa_circRNA_100269 in gastric cancer (GC) samples and cells were examined, and its effects on the biological functions of GC cells were elucidated. The levels of hsa_circRNA_100269 in specimens/cell lines were examined using RT-qPCR. Cell models with hsa_circRNA_100269 overexpression or knockdown were generated using lentiviral vectors. Cell viability was determined by MTT assay; cell migratory/invasive activity was evaluated using wound healing/Transwell assay. Cell cycle arrest and apoptosis were assessed by flow cytometry; expression of associated markers involved in cell apoptosis, EMT and the PI3K/Akt signaling were determined by RT-qPCR/immunoblotting. In vivo study was also performed using hsa_circRNA_100269 knockout mice. Our findings revealed downregulation of hsa_circRNA_100269 in GC tissues compared to non-cancerous control. Additionally, the levels of PI3K were remarkably elevated in GC tissues, where hsa_circRNA_100269 and PI3K was negatively correlated. Moreover, the expression of hsa_circRNA_100269 was associated with histology grade and occurrence of metastasis in GC patients. In addition, hsa_circRNA_100269 was downregulated in GC cells compared to normal gastric epithelial cells. Overexpressed hsa_circRNA_100269 notably inhibited the proliferation, migration, invasion and EMT of GC cells, whereas cell cycle arrest at G0/G1 phase was promoted and cell apoptosis was enhanced. Moreover, the PI3K/Akt signaling was involved in hsa_circRNA_100269-regulated GC cell proliferation, migration, invasion, EMT and apoptosis. Knockdown of hsa_circRNA_100269 also remarkably induced tumor growth in mouse model. In summary, our findings indicated that the levels of hsa_circRNA_100269 were reduced in GC. Furthermore, hsa_circRNA_100269 could suppress the development of GC by inactivating the PI3K/Akt pathway. More importantly, hsa_circRNA_100269/PI3K/Akt axis may be a novel therapeutic candidate for GC treatment.

Curcumin suppresses the malignancy of non-small cell lung cancer by modulating the circ-PRKCA/miR-384/ITGB1 pathway.

BACKGROUND: Curcumin exerts a suppressive effect in tumor growth by acting as a modulator of multiple molecular targets. Circular RNA hsa_circ_0007580 (circ-PRKCA) accelerates the tumorigenesis of non-small cell lung cancer (NSCLC). However, whether curcumin can regulate circ-PRKCA to inhibit NSCLC progression is unclear. METHODS: Cell viability, colony formation, apoptosis, migration, and invasion were analyzed using Cell Counting Kit-8 (CCK-8), plate clone, flow cytometry, or transwell assay. Expression of circ-PRKCA, microRNA (miR)-384, and ITGB1 mRNA (integrin subunit beta 1) mRNA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Curcumin repressed NSCLC growth through regulating circ-PRKCA expression was validated by xenograft assay. The targeting relationship between circ-PRKCA or ITGB1 and miR-384 was verified by dual-luciferase reporter assay. The level of ITGB1 protein was measured by western blotting. RESULTS: Circ-PRKCA and ITGB1 expression were elevated in NSCLC tissues and cells, but miR-384 had an opposing tendency. After curcumin treatment, the expression tendency of circ-PRKCA, miR-384, and ITGB1 in NSCLC cells was overturned. Furthermore, curcumin impeded viability, colony formation, migration, invasion, and accelerated apoptosis of NSCLC cells, but these impacts were partially reversed by circ-PRKCA elevation, miR-384 downregulation, or ITGB1 overexpression. Also, the inhibitory effect of curcumin on xenograft tumor was further enhanced after circ-PRKCA knockdown. Notably, circ-PRKCA regulated ITGB1 expression through sponging miR-384 in curcumin-treated NSCLC cells. CONCLUSIONS: Curcumin inhibited NSCLC growth through downregulating circ-PRKCA, which regulated ITGB1 expression by adsorbing miR-384. This study provided a new mechanism to understand how curcumin inhibited the progression of NSCLC.

Targeting choroidal vascular dysfunction via inhibition of circRNA-FoxO1 for prevention and management of myopic pathology.

Myopia has become a global public health problem due to high prevalence. Although the etiological factors of myopia have been gradually recognized, the underlying mechanism remains largely elusive. Choroidal vascular dysfunction is recognized as a critical vision-threatening complication in myopia. Circular RNAs (circRNAs) are shown as the critical regulators in many biological processes and human diseases. In this study, we investigated the role of circRNAs in choroidal vascular dysfunction in myopia. The level of circFoxO1 was significantly upregulated in myopic choroid. circFoxO1 silencing suppressed choroidal endothelial cell viability, proliferation, migration, and tube formation in vitro and alleviated choroidal vascular dysfunction in vivo and ex vivo. circFoxO1 silencing retarded the progression of myopia as shown by reduced extracellular matrix remodeling and improved refractive error and axial elongation. Mechanistically, circFoxO1 acted as the sponge of miR-145 to sequester and inhibit miR-145 activity, thereby inducing VEGFA or ANGPT2 expression. miR-145 could mimic the effects of circFoxO1 silencing on choroidal endothelial phenotypes. Collectively, intervention of choroidal vascular dysfunction via regulating circFoxO1 level is a potential strategy for the prevention and management of myopia.

Non-coding RNAs and potential therapeutic targeting in cancer.

Recent advances have begun to clarify the physiological and pathological roles of non-coding RNAs (ncRNAs) in various diseases, including cancer. Among these, microRNAs (miRNAs) have been the most studied and have emerged as key players that are involved in the regulation of important growth regulatory pathways in cancer pathogenesis. The ability of a single ncRNA to modulate the expression of multiple downstream gene targets and associated pathways, have provided a rationale to pursue them for therapeutic drug development in cancer. In this context, early data from pre-clinical studies have demonstrated that synthetic miRNA-based therapeutic molecules, along with various protective coating approaches, has allowed for their efficient delivery and anti-tumor activity. In fact, some of the miRNA-based cancer therapeutic strategies have shown promising results even in early-phase human clinical trials. While the enthusiasm for ncRNA-based cancer therapeutics continue to evolve, the field is still in the midst of unraveling a more precise understanding of the molecular mechanisms and specific downstream therapeutic targets of other lesser studied ncRNAs such as the long-non-coding RNAs, transfer RNAs, circular RNAs, small nucleolar RNAs, and piwi-interacting RNAs. This review article provides the current state of knowledge and the evolving principles for ncRNA-based therapeutic approaches in cancer, and specifically highlights the importance of data to date and the approaches that are being developed to overcome the challenges associated with their delivery and mitigating the off-target effects in human cancers.

Circular RNA 100146 Promotes Colorectal Cancer Progression by the MicroRNA 149/HMGA2 Axis.

Colorectal cancer (CRC) has developed into the third leading cause of cancer-associated death worldwide. Studies have confirmed that circular RNAs (circRNAs) absorb microRNAs (miRNAs) to regulate the function of downstream genes. This study aimed to explore the underlying mechanism of circRNA 100146 in CRC. The expression of circRNA 100146, miRNA 149 (miR-149), and high mobility group AT-Hook 2 (HMGA2) was detected by quantitative real-time PCR (RT-qPCR). A series of biofunctional effects (cell viability, apoptosis, migration/invasion) were evaluated by the use of methyl thiazolyl tetrazolium (MTT), flow cytometry, and transwell assays. Protein levels were measured by Western blot assay. A xenograft model was established for in vivo experiments. The interactions among circRNA 100146, miR-149, and HMGA2 were evaluated by dual-luciferase reporter assay, RNA immunoprecipitation assays, or RNA pulldown assay. circRNA 100146 was upregulated in CRC tissues and cells. circRNA 100146 knockdown inhibited cell proliferation, promoted apoptosis, and suppressed migration and invasion in vitro and impeded tumor growth in vivo Also, miR-149 was negatively regulated by circRNA 100146 and was targeted to HMGA2 and mediated its expression. Moreover, miR-149 interference abrogated the activities of silenced circRNA 100146 in proliferation, apoptosis, migration, and invasion. Furthermore, HMGA2 overexpression abated the effects described above caused by circRNA 100146 silencing, while the mutations on miR-149 binding sites in the 3' untranslated region (3'-UTR) of HMGA2 led to its loss of this ability. circRNA 100146 knockdown repressed proliferation, enhanced apoptosis, and hindered migration and invasion in SW620 and SW480 cells through targeting the miR-149/HMGA2 axis.

Hsa_circ_0006872 promotes cigarette smoke-induced apoptosis, inflammation and oxidative stress in HPMECs and BEAS-2B cells through the miR-145-5p/NF-κB axis.

Cigarette smoke is a major cause of chronic obstructive pulmonary disease (COPD). Circular RNAs (circRNAs) are involved in regulating various biological processes. This study aimed to explore the role and molecular basis of hsa_circ_0006872 in cigarette smoke extract (CSE)-induced cell injury. HPMECs and BEAS-2B cells were treated with CSE to mimic COPD in vitro. The levels of hsa_circ_0006872 and miR-145-5p were measured by quantitative real-time polymerase chain reaction. Cell proliferation was assessed via Cell Counting Kit-8 (CCK-8) and colony formation assays. Flow cytometry was used to evaluate apoptosis and cell cycle. The levels of inflammatory factors were assayed via enzyme-linked immunosorbent assay (ELISA). The levels of oxidative stress markers were determined via commercial kits. The interaction between hsa_circ_0006872 and miR-145-5p was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Protein expression was measured using Western blot assay. Hsa_circ_0006872 level was elevated in COPD patients and was negatively correlated with miR-145-5p level. CSE exposure promoted apoptosis, inflammation and oxidative stress of HPMECs and BEAS-2B cells, while hsa_circ_0006872 down-regulation undermined the effects. In addition, hsa_circ_0006872 silencing inhibited CSE-induced cell injury via regulating miR-145-5p. Moreover, CSE contributed to the activation of NF-κB pathway through hsa_circ_0006872/miR-145-5p axis. Hsa_circ_0006872 facilitated CSE-triggered apoptosis, inflammation and oxidative stress in HPMECs and BEAS-2B cells by regulating miR-145-5p/NF-κB pathway.

The promoting effects of hsa_circ_0050102 in pancreatic cancer and the molecular mechanism by targeting miR-1182/NPSR1.

Pancreatic cancer is one of the most lethal tumors across the world with an overall 5-year survival rate of 9%, and great efforts have been devoted in early diagnosis and treatment in the past decades. Competing endogenous RNAs are novel and specific regulatory mechanisms of gene expression, and researches have indicated its important roles in tumor regulation. In this study, we explored the circ-0050102 expression in pancreatic cancer and its impacts on tumor malignant phenotypes and further investigated the correlations among circ-0050102, miR-1182 and NPSR1. Results of real-time quantitative PCR showed that circ-0050102 expressed higher in pancreatic cancers compared with that in adjacent normal tissues. In cell functional experiment, downregulation of circ-0050102 could suppress cell proliferation, migration and invasion ability, boost cell apoptosis and arrest cell cycle in both PANC-1 and CFPAC-1 cells. Furthermore, allogeneic transplantation in nude mice was performed and results showed that the inhibition of circ-0050102 could slow down tumor formation in vivo. Mechanism research suggested that circ-0050102 could downregulate miR-1182, while miR-1182 could not influence the expression of circ-0050102, and miR-1182 could directly target at NPSR1 and suppress it. Moreover, circ-0050102 could reverse the effects of si-NPSR1 on pancreatic cancer cells. In conclusion, we identified that circ-0050102 played an important role in promoting pancreatic cancer by regulating the miR-1182/NPSR1 pathway.

A novel circular RNA hsa_circRNA_103809/miR-377-3p/GOT1 pathway regulates cisplatin-resistance in non-small cell lung cancer (NSCLC).

BACKGROUND: Cisplatin is the first-line chemotherapeutic drug for non-small cell lung cancer (NSCLC), and emerging evidences suggests that targeting circular RNAs (circRNAs) is an effective strategy to increase cisplatin-sensitivity in NSCLC, but the detailed mechanisms are still not fully delineated. METHODS: Cell proliferation, viability and apoptosis were examined by using the cell counting kit-8 (CCK-8) assay, trypan blue staining assay and Annexin V-FITC/PI double staining assay, respectively. The expression levels of cancer associated genes were measured by using the Real-Time qPCR and Western Blot analysis at transcriptional and translated levels. Dual-luciferase reporter gene system assay was conducted to validated the targeting sites among hsa_circRNA_103809, miR-377-3p and 3' untranslated region (3'UTR) of GOT1 mRNA. The expression status, including expression levels and localization, were determined by immunohistochemistry (IHC) assay in mice tumor tissues. RESULTS: Here we identified a novel hsa_circRNA_103809/miR-377-3p/GOT1 signaling cascade which contributes to cisplatin-resistance in NSCLC in vitro and in vivo. Mechanistically, parental cisplatin-sensitive NSCLC (CS-NSCLC) cells were subjected to continuous low-dose cisplatin treatment to generate cisplatin-resistant NSCLC (CR-NSCLC) cells, and we found that hsa_circRNA_103809 and GOT1 were upregulated, while miR-377-3p was downregulated in CR-NSCLC cells but not in CS-NSCLC cells. In addition, hsa_circRNA_103809 sponged miR-337-3p to upregulate GOT1 in CS-NSCLC cells, and knock-down of hsa_circRNA_103809 enhanced the inhibiting effects of cisplatin on cell proliferation and viability, and induced cell apoptosis in CR-NSCLC cells, which were reversed by downregulating miR-377-3p and overexpressing GOT1. Consistently, overexpression of hsa_circRNA_103809 increased cisplatin-resistance in CS-NSCLC cells by regulating the miR-377-3p/GOT1 axis. Finally, silencing of hsa_circRNA_103809 aggravated the inhibiting effects of cisplatin treatment on NSCLC cell growth in vivo. CONCLUSIONS: Analysis of data suggested that targeting the hsa_circRNA_103809/miR-377-3p/GOT1 pathway increased susceptibility of CR-NSCLC cells to cisplatin, and this study provided novel targets to improve the therapeutic efficacy of cisplatin for NSCLC treatment in clinic.

circFAT1(e2) Promotes Papillary Thyroid Cancer Proliferation, Migration, and Invasion via the miRNA-873/ZEB1 Axis.

Circular RNAs (circRNAs) play an extremely important regulatory role in the occurrence and development of various malignant tumors including papillary thyroid cancer (PTC). circFAT1(e2) is a new type of circRNA derived from exon 2 of the FAT1 gene, which is distributed in the cytoplasm and nucleus of PTC cells. However, so far, the role of circFAT1(e2) in PTC is still unclear. In this study, circFAT1(e2) was found to be highly expressed in PTC cell lines and tissues. circFAT1(e2) knockdown suppressed PTC cell growth, migration, and invasion. Also, circFAT1(e2) acted as a sponge for potential microRNAs (miRNAs) to modulate cancer progression. A potential miRNA target was discovered to be miR-873 which was targeted by circFAT1(e2) in PTC. The dual-luciferase assay conducted later also confirmed that there was indeed a direct interaction between circFAT1(e2) and miR-873. This study also confirmed that circFAT1(e2) inhibited the miR-873 expression and thus promoted the ZEB1 expression, thus affecting the proliferation, metastasis, and invasion of PTC cells. In conclusion, the results of this study indicated that circFAT1(e2) played a carcinogenic role by targeting the miR-873/ZEB1 axis to promote PTC invasion and metastasis, which might become a potential novel target for therapy of PTC.

Depletion of circ_0007841 inhibits multiple myeloma development and BTZ resistance via miR-129-5p/JAG1 axis.

Circular RNAs (circRNAs) possess important regulatory effects on multiple myeloma (MM) progression. Here, we aimed at exploring the function of circ_0007841 in MM and the underlying molecular mechanism. Expression of circ_0007841, microRNA (miR)-129-5p and Jagged1 (JAG1) was determined via qRT-PCR or western blot assay. Methyl thiazolyl tetrazolium (MTT) assay was applied to examine cell viability and IC50 value of MM cells to bortezomib (BTZ). Colony formation assay was performed to analyze cell proliferation. Moreover, cell apoptosis was assessed by flow cytometry and western blot analysis. Cell metastasis was evaluated by wound healing assay and Transwell assay. Function of circ_0007841 in vivo was determined by xenograft tumor assay. Target relationship between miR-129-5p and circ_0007841 or JAG1 was confirmed via dual-luciferase reporter, RNA immunoprecipitation (RIP) and pull-down assays. The up-regulation of circ_0007841 and JAG1, and the down-regulation of miR-129-5p were detected in MM bone marrow aspirates and cells. Circ_0007841 knockdown significantly repressed cell proliferation, chemoresistance, and metastasis, while contributed to apoptosis of MM cells in vitro, and reduced tumor growth in vivo. Circ_0007841 targeted miR-129-5p, and miR-129-5p inhibition reversed impact of silencing of circ_0007841 on MM cells. JAG1 was a mRNA target of miR-129-5p, whose overexpression could undermine the miR-129-5p-mediated effects on MM cells. Circ_0007841 positively regulated JAG1 expression via absorbing miR-129-5p. Circ_0007841 knockdown inhibited MM cell proliferation, metastasis and chemoresistance through modulating miR-129-5p/JAG1 axis, suggesting that circ_0007841 might serve as a potential therapeutic target of MM.

Circ_0008450 downregulates Runx3 to promote the proliferation and epithelial-mesenchymal transition of human keratinized epithelial cells.

Keloid is an extremely common and often overlooked benign neoplastic disease, but its consequences should not be underestimated. Therefore, a deep exploration of the pathological mechanism of keloid becomes very essential. After 22 samples were collected from each patient's keloid tissues and normal skin tissues, circ_0008450 and Runx3 expression was tested by qRT-PCR. When primary human keratinized epithelial cells were transfected by sh-circ_0008450 or sh-Runx3, cell proliferation, apoptosis, migration, and EMT process were assessed by CCK-8, BrdU assay, apoptosis assay, migration assay, and Western blot. Finally, transfection was performed to explore the effect of circ_0008450 on the TGF-ß/Smad signal pathway by adopting western blot. Circ_0008450 was highly expressed in keratinized epithelial tissues. After the transfection of sh-circ_0008450 into primary human keratinized epithelial cells, cell proliferation, migration, and EMT process were inhibited, and apoptosis was stimulated. Moreover, circ_0008450 silence-induced above changes were partly reversed by transfecting sh-Runx3. In addition, transfecting sh-circ_0008450 could repress TGF-ß/Smad pathway, while transfecting sh-Runx3 activated the above pathway. Circ_0008450 down-regulated Runx3 to promote the proliferation and EMT process of human keratinized epithelial cells. This discovery may be related to the activation of the TGF-ß/Smad pathway.

A Circle RNA Regulatory Axis Promotes Lung Squamous Metastasis via CDR1-Mediated Regulation of Golgi Trafficking.

Lung squamous carcinoma (LUSC) is a highly metastatic disease with a poor prognosis. Using an integrated screening approach, we found that miR-671-5p reduces LUSC metastasis by inhibiting a circular RNA (circRNA), CDR1as. Although the putative function of circRNA is through miRNA sponging, we found that miR-671-5p more potently silenced an axis of CDR1as and its antisense transcript, cerebellar degeneration related protein 1 (CDR1). Silencing of CDR1as or CDR1 significantly inhibited LUSC metastases and CDR1 was sufficient to promote migration and metastases. CDR1, which directly interacted with adaptor protein 1 (AP1) complex subunits and coatomer protein I (COPI) proteins, no longer promoted migration upon blockade of Golgi trafficking. Therapeutic inhibition of the CDR1as/CDR1 axis with miR-671-5p mimics reduced metastasis in vivo. This report demonstrates a novel role for CDR1 in promoting metastasis and Golgi trafficking. These findings reveal an miRNA/circRNA axis that regulates LUSC metastases through a previously unstudied protein, CDR1. SIGNIFICANCE: This study shows that circRNA, CDR1as, promotes lung squamous migration, metastasis, and Golgi trafficking through its complimentary transcript, CDR1.

Circular RNA CircITGA7 Promotes Tumorigenesis of Osteosarcoma via miR-370/PIM1 Axis.

Many studies have shown that there are many circular RNA (circRNA) expression abnormalities in osteosarcoma (OS), and this abnormality is related to the development of osteosarcoma. But at present, it is unclear as to what circITGA7 has in the OS and what it does. In this study, qRT-PCR was used to detect the expression of circITGA7, miR-370, and PIM1 mRNA in OS tissues and cells. The CCK-8 assay was used to detect the effect of circITGA7 on cell proliferation. Later, the transwell assay was used to detect cell migration and invasion. The dual-luciferase reporter assay confirmed the existence of the targeting relationship between circITGA7 and miR-370, and miR-370 and PIM1. We found that circITGA7 was upregulated in OS tissues and cell lines. Knockdown of circITGA7 weakened the cell's ability to proliferate and metastasize. Furthermore, we observed that miR-370 was negatively regulated by circITGA7, while PIM1 was positively regulated by it. A functional assay validated that circITGA7 promoted OS progression via suppressing miR-370 and miR-370 affected OS proliferation and migration via PIM6 in OS. In summary, this study shows that circITGA7 promotes OS proliferation and metastasis via miR-370/PIM1.

Circular RNA cir-ITCH Is a Potential Therapeutic Target for the Treatment of Castration-Resistant Prostate Cancer.

cir-ITCH, a well-known tumor-suppressive circular RNA, plays a critical role in different cancers. However, its expression and functional role in prostate cancer (PCa) are unclear. Herein, we explored the potential mechanism and tumor-inhibiting role of cir-ITCH in PCa. Using reverse transcriptase polymerase chain reaction assay, we analyzed the expression of cir-ITCH in PCa and paired adjacent nontumor tissue samples resected during surgical operation, as well as in two cell lines of human PCa (LNCaP and PC-3) and the immortalized normal prostate epithelial cell line (RWPE-1). Cell viability and migration of PCa cell lines were evaluated using CCK-8 and wound-healing assays. Expression of key proteins of the Wnt/ß-catenin and PI3K/AKT/mTOR pathways was detected using western blotting. We found that cir-ITCH expression was typically downregulated in the tissues and cell lines of PCa compared to that in the peritumoral tissue and in RWPE-1 cells, respectively. The results showed that cir-ITCH overexpression significantly inhibits the proliferation, migration, and invasion of human PCa cells and that reciprocal inhibition of expression occurred between cir-ITCH and miR-17. Proteins in the Wnt/ß-catenin and PI3K/AKT/mTOR pathways were downregulated by overexpression of cir-ITCH both in androgen receptor-positive LNCaP cells and androgen receptor-negative PC-3 cells. Taken together, these data demonstrated that cir-ITCH plays a tumor-suppressive role in human PCa cells, partly through the Wnt/ß-catenin and PI3K/AKT/mTOR pathways. Thus, cir-ITCH may serve as a novel therapeutic target for the treatment of PCa, especially castration-resistant prostate cancer.

Downregulation of hsa_circ_0000936 sensitizes resistant glioma cells to temozolomide by sponging miR-1294.

Glioma is one of the most aggressive forms of brain tumor and is hallmarked by high rate of mortality, metastasis and drug resistance. Herein, we explore the role of circular RNA (circRNA) hsa_circ_0000936 in the resistance of glioma cells to temozolomide (TMZ). In this study, Relative changes in gene expression levels were compared using qRT-PCR. The role of hsa_circ_0000936 was characterized by cell count kit -8 assay and flow cytometry. Luciferase reporter assay was carried out for target validation.We found that hsa_circ_0000936 was upregulated in glioma tissues as compared to their adjacent normal tissues. Increased expression of hsa_circ_0000936 was found in the glioma tissues of patients showing resistance to TMZ compared with that of patients showing sensitivity to TMZ. The upregulation of hsa_circ_0000936 was also confirmed in TMZresistant glioma cells. miR-1294 was downregulated in TMZ-resistant glioma cells and identified as a direct target of hsa_circ_0000936. Downregulation of hsa_circ_0000936 increased the sensitivity of TMZ-resistant glioma cells towards TMZ. Moreover, restoration of miR-1294 could abrogate the promoting effect of hsa_circ_0000936 on TMZ resistance in TMZ-resistant glioma cells. In conclusion, downregulation of hsa_circ_0000936 sensitizes TMZ-resistant glioma cells to TMZ by sponging miR-1294, suggesting that hsa_circ_0000936 may be a potential target for overcoming the resistance of glioma cells to TMZ.