Project description:BackgroundMost Colorectal Cancer (CRC) patients exhibit limited responsiveness to anti-programmed cell death protein 1 (PD-1) therapy, with the underlying mechanisms remaining elusive. Circular RNAs (circRNAs) play a significant role in tumorigenesis and development, with potential applications in tumor screening and predicting treatment efficacy. However, there are few studies exploring the role of circRNAs in CRC immune evasion.MethodscircRNA microarrays were used to identify circPHLPP2. RT-qPCR was used to examine the associations between the expression level of circPHLPP2 and the clinical characteristics of CRC patients. MTS assay, clone formation experiment, subcutaneous tumor implantation and multicolor flow cytometry were used to confirm the biological function of circPHLPP2. RAN-seq, RT-qPCR, and WB experiments were performed to investigate the downstream signaling pathways involved in circPHLPP2. RNA pull-down, RNA immunoprecipitation (RIP) and immunofluorescence staining were performed to identify the proteins associated with circPHLPP2.ResultscircPHLPP2 is up-regulated in CRC patients who exhibit resistance to anti-PD-1 based therapy. circPHLPP2 significantly promotes the proliferation and tumor growth of CRC cells. Knockdown of circPhlpp2 enhances the efficacy of anti-PD-1 in vivo. Mechanistically, the specific interaction between circPHLPP2 and ILF3 facilitates the nuclear accumulation of ILF3, which subsequently enhances the transcription of IL36γ. This process reduces NK cell infiltration and impairs NK cells' granzyme B and IFN-γ production, thereby promoting tumor progression.ConclusionsOverall, our findings reveal a novel mechanism by which circRNA regulates CRC immune evasion. circPHLPP2 may serve as a prognostic biomarker and potential therapeutic target for CRC patients.
Project description:BACKGROUND:Immune system evasion, distance tumor metastases, and increased cell proliferation are the main reasons for the progression of non-small cell lung cancer (NSCLC) and the death of NSCLC patients. Dysregulation of circular RNAs plays a critical role in the progression of NSCLC; therefore, further understanding the biological mechanisms of abnormally expressed circRNAs is critical to discovering novel, promising therapeutic targets for NSCLC treatment. METHODS:The expression of circular RNA fibroblast growth factor receptor 1 (circFGFR1) in NSCLC tissues, paired nontumor tissues, and cell lines was detected by RT-qPCR. The role of circFGFR1 in NSCLC progression was assessed both in vitro by CCK-8, clonal formation, wound healing, and Matrigel Transwell assays and in vivo by a subcutaneous tumor mouse assay. In vivo circRNA precipitation, RNA immunoprecipitation, and luciferase reporter assays were performed to explore the interaction between circFGFR1 and miR-381-3p. RESULTS:Here, we report that circFGFR1 is upregulated in NSCLC tissues, and circFGFR1 expression is associated with deleterious clinicopathological characteristics and poor prognoses for NSCLC patients. Forced circFGFR1 expression promoted the migration, invasion, proliferation, and immune evasion of NSCLC cells. Mechanistically, circFGFR1 could directly interact with miR-381-3p and subsequently act as a miRNA sponge to upregulate the expression of the miR-381-3p target gene C-X-C motif chemokine receptor 4 (CXCR4), which promoted NSCLC progression and resistance to anti-programmed cell death 1 (PD-1)- based therapy. CONCLUSION:Taken together, our results suggest the critical role of circFGFR1 in the proliferation, migration, invasion, and immune evasion abilities of NSCLC cells and provide a new perspective on circRNAs during NSCLC progression.
Project description:BackgroundDysregulation of circular RNAs (circRNAs) plays an important role in the development of gastric cancer; thus, revealing the biological and molecular mechanisms of abnormally expressed circRNAs is critical for identifying novel therapeutic targets in gastric cancer.MethodsA circRNA microarray was performed to identify differentially expressed circRNAs between primary and distant metastatic tissues and between gastric cancer tissues sensitive or resistant to anti-programmed cell death 1 (PD-1) therapy. The expression of circRNA discs large homolog 1 (DLG1) was determined in a larger cohort of primary and distant metastatic gastric cancer tissues. The role of circDLG1 in gastric cancer progression was evaluated both in vivo and in vitro, and the effect of circDLG1 on the antitumor activity of anti-PD-1 was evaluated in vivo. The interaction between circDLG1 and miR-141-3p was assessed by RNA immunoprecipitation and luciferase assays.ResultscircDLG1 was significantly upregulated in distant metastatic lesions and gastric cancer tissues resistant to anti-PD-1 therapy and was associated with an aggressive tumor phenotype and adverse prognosis in gastric cancer patients treated with anti-PD-1 therapy. Ectopic circDLG1 expression promoted the proliferation, migration, invasion, and immune evasion of gastric cancer cells. Mechanistically, circDLG1 interacted with miR-141-3p and acted as a miRNA sponge to increase the expression of CXCL12, which promoted gastric cancer progression and resistance to anti-PD-1-based therapy.ConclusionsOverall, our findings demonstrate how circDLG1 promotes gastric cancer cell proliferation, migration, invasion and immune evasion and provide a new perspective on the role of circRNAs during gastric cancer progression.
Project description:BackgroundColorectal cancer (CRC) is the second leading cause of cancer-related deaths globally. It is essential to identify new CRC-associated therapeutic targets and diagnostic biomarkers. Previous studies have demonstrated that a series of circular RNAs (circRNAs) play a crucial role in CRC pathogenesis. This study assessed the potential of hsa_circ_0064559 in tumor cell growth and progression of CRC.MethodsSix pairs of matched CRC and normal colorectal tissue samples were sequenced using the Affymetrix Clariom D array. Using RNA interference, the expression of thirteen circRNAs was knocked down in CRC cells. The proliferation of CRC cell lines (RKO and SW620 cells) was detected using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Apoptosis and cell cycle were determined by flow-cytometric analysis. An in vivo study uses nude mice to establish a CRC mouse model. The differentially expressed genes were analyzed using Affymetrix primeview human GeneChip array and verified by polymerase chain reaction.ResultsAffymetrix Clariom D array analysis revealed that thirteen circRNAs were upregulated in CRC. The proliferation of CRC cell lines was decreased, while the proportion of apoptotic and G1 phase cells was higher after hsa_circ_0064559 knockdown. In vivo xenograft nude mice model revealed that the volume and weight of the tumor were reduced by hsa_circ_0064559 knockdown. In Affymetrix primeview human GeneChip array, we found six upregulated genes (STAT1, ATF2, TNFRSF10B, TGFBR2, BAX, and SQSTM1) and two downregulated genes (SLC4A7 and CD274) related to apoptosis and proliferation of colorectal cancer cells after hsa_circ_0064559 knockdown.ConclusionsThe hsa_circ_0064559 knockdown could inhibit the proliferation, promote apoptosis in CRC cell lines in vitro, and inhibit the development of CRC tumors in vivo. The mechanism may be related to activating a wide range of signaling pathways. The hsa_circ_0064559 may be a potential biomarker for early diagnosis or prognosis of CRC and a novel drug target for CRC therapy.
Project description: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.
Project description:BackgroundCircular RNAs (circRNAs) are well-known regulators of cancer progression and chemoresistance in various types of cancers. This study was performed to investigate the function of hsa_circ_0000277 in esophageal squamous cell carcinoma (ESCC).MethodsRNA levels were analyzed via the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell Counting Kit-8 (CCK-8) assay was applied to determine cell proliferation and half maximal inhibitory concentration (IC50) of cisplatin (DDP). Colony formation ability was evaluated by colony formation assay. Cell cycle and apoptosis were measured using flow cytometry. RNA immunoprecipitation (RIP), pull-down assay and dual-luciferase reporter assays were performed for target interaction analysis. The protein levels were determined through western blot. Xenograft models were established for researching hsa_circ_0000277 function in vivo.ResultsHsa_circ_0000277 expression was increased in ESCC cells and tissues, and it had important clinical significance. Downregulation of hsa_circ_0000277 repressed ESCC cell proliferation, colony formation, cell cycle, and DDP resistance. Hsa_circ_0000277 acted as a microRNA-873-5p (miR-873-5p) sponge and Sry-related high-mobility group box 4 (SOX4) was validated as a target of miR-873-5p. Moreover, hsa_circ_0000277/miR-873-5p axis and miR-873-5p/SOX4 axis regulated ESCC cell progression and DDP resistance. Hsa_circ_0000277/miR-873-5p axis activated SOX4/Wnt/β-catenin signaling pathway. Hsa_circ_0000277 facilitated tumorigenesis and DDP resistance by miR-873-5p/SOX4 axis in vivo.ConclusionThese findings unraveled that hsa_circ_0000277 promoted ESCC progression and DDP resistance via miR-873-5p/SOX4/Wnt/β-catenin axis, showing a specific molecular mechanism of carcinogenesis and chemoresistance in ESCC.
Project description:Colorectal cancer (CRC) is the second most common malignant tumor worldwide, and its incidence rate increases annually. Early diagnosis and treatment are crucial for improving the prognosis of patients with colorectal cancer. Circular RNAs are noncoding RNAs with a closed-loop structure that play a significant role in tumor development. However, the role of circular RNAs in CRC is poorly understood. The circular RNA hsa_circ_0000467 was screened in CRC circRNA microarrays using a bioinformatics analysis, and the expression of hsa_circ_0000467 in CRC tissues was determined by in situ hybridization. The associations between the expression level of hsa_circ_0000467 and the clinical characteristics of CRC patients were evaluated. Then, the role of hsa_circ_0000467 in CRC growth and metastasis was assessed by CCK8 assay, EdU assay, plate colony formation assay, wound healing assay, and Transwell assay in vitro and in a mouse model of CRC in vivo. Proteomic analysis and western blotting were performed to investigate the effect of hsa_circ_0000467 on c-Myc signaling. Polysome profiling, RT‒qPCR and dual-luciferase reporter assays were performed to determine the effect of hsa_circ_0000467 on c-Myc translation. RNA pull-down, RNA immunoprecipitation (RIP) and immunofluorescence staining were performed to assess the effect of hsa_circ_0000467 on eIF4A3 distribution. In this study, we found that the circular RNA hsa_circ_0000467 is highly expressed in colorectal cancer and is significantly correlated with poor prognosis in CRC patients. In vitro and in vivo experiments revealed that hsa_circ_0000467 promotes the growth and metastasis of colorectal cancer cells. Mechanistically, hsa_circ_0000467 binds eIF4A3 to suppress its nuclear translocation. In addition, it can also act as a scaffold molecule that binds eIF4A3 and c-Myc mRNA to form complexes in the cytoplasm, thereby promoting the translation of c-Myc. In turn, c-Myc upregulates its downstream targets, including the cell cycle-related factors cyclin D2 and CDK4 and the tight junction-related factor ZEB1, and downregulates E-cadherin, which ultimately promotes the growth and metastasis of CRC. Our findings revealed that hsa_circRNA_0000467 plays a role in the progression of CRC by promoting eIF4A3-mediated c-Myc translation. This study provides a theoretical basis and molecular target for the diagnosis and treatment of CRC.
Project description:BACKGROUND:Circular RNAs (circRNAs) have recently been identified as potential functional modulators of the cellular physiology processes. The study aims to uncover the potential clinical value and driving molecular mechanisms of circRNAs in gallbladder cancer (GBC). PATIENTS AND METHODS:We performed RNA sequencing from four GBC and paired adjacent normal tissues to analyze the circRNA candidates. Quantitative real-time polymerase chain reaction (QRT-PCR) was used to measure the circFOXP1 expression from 40 patient tissue samples. Short hairpin RNA mediated knockdown or exogenous expression of circFOXP1 combined with in vitro and in vivo assays were performed to prove the functional significance of circFOXP1. Double luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays were also performed. RESULTS:By performing RNA sequencing from GBC and paired adjacent normal tissues to analyze the circRNA candidates, we identified that circFOXP1 (hsa_circ_0008234) expression was significantly upregulated in GBC tissues and positively associated with lymph node metastasis, advanced TNM stage and poor prognosis in patients. Short hairpin RNA mediated knockdown or exogenous expression of circFOXP1 combined with in vitro assays demonstrated that circFOXP1 has pleiotropic effects, including promotion of cell proliferation, migration, invasion, and inhibition of cell apoptosis in GBC. In vivo, circFOXP1 promoted tumor growth. Mechanistically, double luciferase reporter, RNA immunoprecipitation (RIP) and biotin-labeled RNA pull-down assays clarified that circFOXP1 interacted with PTBP1 that could bind to the 3'UTR region and coding region (CDS) of enzyme pyruvate kinase, liver and RBC (PKLR) mRNA (UCUU binding bites) to protect PKLR mRNA from decay. Additionally, circFOXP1 acted as the sponge of miR-370 to regulate PKLR, resulting in promoting Warburg effect in GBC progression. CONCLUSIONS:These results demonstrated that circFOXP1 serve as a prognostic biomarker and critical regulator in GBC progression and Warburg effect, suggesting a potential target for GBC treatment.
Project description:BackgroundAn immunosuppressive tumor microenvironment in ovarian cancer facilitates tumor progression and resistance to immunotherapy. The function of MYB Proto-Oncogene Like 2 (MYBL2) in the tumor microenvironment remains largely unexplored.MethodsA syngeneic intraovarian mouse model, flow cytometry analysis, and immunohistochemistry were used to explore the biological function of MYBL2 in tumor progression and immune escape. Molecular and biochemical strategies-namely RNA-sequencing, western blotting, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay, multiplex immunofluorescence, chromatic immunoprecipitation assay (CHIP) and luciferase assay-were used to reveal the mechanisms of MYBL2 in the OVC microenvironment.ResultsWe found tumor derived MYBL2 indicated poor prognosis and selectively correlated with tumor associated macrophages (TAMs) in ovarian cancer. Mechanically, C-C motif chemokine ligand 2 (CCL2) transcriptionally activated by MYBL2 induced TAMs recruitment and M2-like polarization in vitro. Using a syngeneic intraovarian mouse model, we identified MYBL2 promoted tumor malignancyand increased tumor-infiltrating immunosuppressive macrophages. Cyclin-dependent kinase 2 (CDK2) was a known upstream kinase to phosphorylate MYBL2 and promote its transcriptional function. The upstream inhibitor of CDK2, CVT-313, reprogrammed the tumor microenvironment and reduced anti-PD-1 resistance.ConclusionsThe MYBL2/CCL2 axis contributing to TAMs recruitment and M2-like polarization is crucial to immune evasion and anti-PD-1 resistance in ovarian cancer, which is a potential target to enhance the efficacy of immunotherapy.
Project description:Inflammation plays a crucial role in cancer progression, but the relevance of the inflammasome remains unclear. Alu RNA was the first endogenous nucleic acid shown to activate the NLRP3 (nucleotide-binding domain leucine-rich repeat containing 3) inflammasome. Here, we showed that Alu RNA can induce epithelial-to-mesenchymal transition (EMT) through NLRP3 inflammasome activation and IL-1β release in colorectal cancer (CRC) cells. Alu RNA is stored, transported and transferred to CRC cells by exosomes. Exosomal Alu RNA promotes tumorigenesis by inducing invasion, metastasis and EMT via NLRP3 inflammasome activation. Consistent with these data, we found that significantly increased Alu RNA expression correlates with the induction of NLRP3 priming in human CRC patients. Furthermore, the level of Alu RNA in circulating exosomes correlates with CRC progression in a preclinical model. These findings reveal the direct involvement of Alu RNA in cancer pathogenesis, and its presence in CRC cell-derived exosomes could be used as a noninvasive diagnostic biomarker.