Lantern-shaped flexible RNA origami for Smad4 mRNA delivery and growth suppression of colorectal cancer.

mRNA delivery has shown high application value in the treatment of various diseases, but its effective delivery is still a major challenge at present. Herein, we propose a lantern-shaped flexible RNA origami for mRNA delivery. The origami is composed of a target mRNA scaffold and only two customized RGD-modified circular RNA staples, which can compress the mRNA into nanoscale and facilitate its endocytosis by cells. In parallel, the flexible structure of the lantern-shaped origami allows large regions of the mRNA to be exposed and translated, exhibiting a good balance between endocytosis and translation efficiency. The application of lantern-shaped flexible RNA origami in the context of the tumor suppressor gene, Smad4 in colorectal cancer models demonstrates promising potential for accurate manipulation of protein levels in in vitro and in vivo settings. This flexible origami strategy provides a competitive delivery method for mRNA-based therapies.

PLXNC1: A Novel Potential Immune-Related Target for Stomach Adenocarcinoma.

BACKGROUND: Gastric cancer is associated with tumor microenvironment and chronic inflammation, but the underlying tumor-promoting mechanisms still remain unknown. METHODS: The ATAC-seq was used to identify genes with chromatin accessibilities in promoter regions. The RNA-seq datasets were performed to identify differentially expressed genes (DEGs). Pearson correlation analysis with the mRNA expression of three families of tumor-related inflammation TFs was used to filter downstream DEGs. Cox univariate survival analysis was performed to identify the prognostic value. The ImmPort database and CIBERSORTx algorithm were used to investigate the regulatory relationship between hub DEGs and immune cells. Immunohistochemistry (IHC) and multidimensional database were performed to verification. RESULTS: In this case, we require 2,454 genes with chromatin accessibility in promoter regions by ATAC-seq. Based on the gene expression profiles (RNA-seq), we identified 365 genes with chromatin accessibility and differential expression. Combined with the Cox univariate survival analysis, we identified 32 survival-related DEGs with chromatin accessibility. According to ImmPort database, CXCL3, PLXNC1, and EDN2 were identified as immune- related genes in STAD. By applying the CIBERSORTx algorithm and Pearson correlation, PLXNC1 was the only gene correlated with various immune cells, significantly associated with M2 macrophages. Furthermore, gene set variation analysis (GSVA) suggests the "hallmark_interferon_gamma_response" pathway was most significantly correlated with PLXNC1. Immunohistochemistry results revealed that PLXNC1 protein level was significantly higher in STAD tissues than in normal tissues (p < 0.001). CONCLUSION: PLXNC1, regulated by IRF5, is an immune-related gene that was significantly associated with M2 macrophages and poor outcome in stomach adenocarcinoma.

An all-in-one homogeneous DNA walking nanomachine and its application for intracellular analysis of miRNA.

DNA walker is a powerful type of DNA nanomachine that can produce amplified signals during the "burnt-bridge"-like walking process. Despite their successful application in extracellular bioanalysis, the heterogeneity of the existing DNA walkers makes it difficult to guarantee the consistency of the results during the analysis of different cells. Methods: Here, an all-in-one homogeneous DNA walking nanomachine is reported that can be delivered into living cells for intracellular bioanalysis of miRNA without auxiliary materials. Results: This DNA walking nanomachine is constructed of gold nanoparticles on which two types of interrelated DNA tracks are assembled. The target miRNA, cancer-related miR-21, can be captured by one of the tracks (track 1) and then walk to the other track (track 2), releasing the hybrid of track 1 and track 2 from the nanoparticle to produce a signal. The walking process can proceed in a cyclic 1-2-1-2 manner and thereby produce amplified signals. Thus, sensitive imaging of the miRNA in situ can be achieved. Conclusion: Benefiting from the homogeneity of the detection system, the method can be applied for intracellular analysis without interference induced by the fluctuations of stimuli or accessorial contents.

Comprehensive analysis of differentially expressed circRNAs revealed a ceRNA network in pancreatic ductaladenocarcinoma.

INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies. However, the molecular mechanisms underlying PDAC are still not completely understood. Circular RNAs (circRNAs) are a unique class of RNA formed by special loop splicing. More and more researchers have paid attention to circRNAs. MATERIAL AND METHODS: In this study, we constructed a circRNA-mediated competing endogenous RNA (ceRNA) network in PDAC. Gene ontology (GO) analysis was performed to explore circRNAs' potential roles in PDAC progression. We also constructed an up-stream transcriptional network of circRNAs' parental genes and found that many transcription factors (TFs), such as tumor protein p53 (TP53) and MYC, could regulate their expression. RESULTS: This study, which aimed to identify differentially expressed circRNAs in PDAC, suggested that circRNAs may also act as biomarkers for PDAC. We analyzed two public datasets (GSE69362 and GSE79634) to identify differentially expressed circRNAs in PDAC. Finally, we found that DExH-Box Helicase 9 (DHX9) may be a potential regulator of circRNA formation in PDAC. Genomic loci of four down-regulated circRNAs - hsa_circ_000691, hsa_circ_0049392, hsa_circ_0005203, and hsa_circ_0001626 - contained DHX9 binding sites, suggesting that they may be directly regulated by DHX9. CONCLUSIONS: Our study identified differentially expressed circRNAs in PDAC, suggesting that circRNAs may also act as biomarkers for PDAC. Additional investigations of function and up-stream regulation of differentially expressed circRNA in PDAC are still needed.

Therapeutic Suppression of miR-4261 Attenuates Colorectal Cancer by Targeting MCC.

The mutated in colorectal cancer (MCC) gene is an important colorectal tumor suppressor gene, although few studies have reported the microRNA(s) that could directly target MCC in colorectal cancer. Here, we used microRNA (miRNA) target prediction algorithms, and previously reported microarray data in human colorectal cancer found that only miR-4261 was predicted by all three databases to directly target MCC. Based on specimens from our own cohort of colorectal cancer patients, we further demonstrated that miR-4261 was overexpressed in colorectal cancer. Interestingly, overexpression of miR-4261 could enhance cell proliferation and G1/S phase transition of cell cycle, and promote cell migration in HCT116 and HT29 cells, while inhibition of miR-4261 had opposite effects. Luciferase reporter assay and western blot analysis confirmed MCC as a direct target of miR-4261. MCC small interfering RNA (siRNA) could abolish the suppressive effects of miR-4261 inhibitor on cell proliferation and migration in HCT116 and HT29 cell lines. Finally, we showed that therapeutic intervention with lentivirus-based miR-4261 sponge injection could effectively reduce tumor growth and inhibit cell proliferation in colorectal cancer xenograft. Collectively, our study is the first one to unravel the functional role of miR-4261, and it provides strong evidence that inhibition of miR-4261 through targeting of MCC might exert a therapeutic effect for colorectal cancer.

miR-224 Controls Human Colorectal Cancer Cell Line HCT116 Proliferation by Targeting Smad4.

Background: Better understanding the molecular mechanisms responsible for the genesis and progression of colorectal cancer would help advance the novel therapeutics. miR-224 has been identified to be elevated in colorectal cancer and promote human colorectal cancer cell line SW480 proliferation and invasion. However, the effect of miRNAs on cancer cell proliferation could be significantly changeable among different cell lines. HCT116 is a commonly used cell line for colorectal cancer study and the target gene responsible for the function of miR-224 in its proliferation is unclear. Methods: miR-224 expression was determined by quantitative reverse transcription polymerase chain reactions (PCRs) in human colorectal cancer tissues compared with their corresponding matched peritumoral tissues. HCT116 cell viability and cell proliferation were determined by CCK-8, EdU incorporation assays and flow cytometry for cell cycle. Target gene of miR-224 was confirmed by Western blots and siRNA for Smad4. Results: miR-224 was significantly increased by 29.49 fold in colorectal cancer tissues compared with their corresponding matched peritumoral tissues based on 12 colorectal cancer patients. miR-224 mimic significantly increased HCT116 cell viability, EdU positive cells rate, and decreased G1 phase cell population and increased S phase cell population. miR-224 inhibitor had opposite effects. Smad4 could be negatively regulated by miR-224 in HCT116 cells and was responsible for its effects in proliferation. Conclusion: miR-224 mediates HCT116 cell proliferation by targeting Smad4.

Therapeutic Inhibition of miR-4260 Suppresses Colorectal Cancer via Targeting MCC and SMAD4.

Dysregulation of microRNAs (miRNAs, miRs) and their putative target genes have been increasingly reported to contribute to colorectal cancer. However, miRNAs that directly target the mutated in colorectal cancer (MCC) gene, a tumor suppressor which is downregulated or inactivated in colorectal cancer, remain largely unknown. By using an array-based miRNA analysis, we identified a group of miRNAs that were dysregulated in human metastatic versus non-metastatic colorectal cancer tissues. One of these miRNAs, miR-4260, was predicted to target MCC in the miRDB database. Results using human HCT116 and HT29 colorectal cancer cell lines showed that miR-4260 mimic enhanced cell proliferation and migration and reduced apoptosis induced by the chemotherapeutic agent 5-fluorouracil while miR-4260 inhibitor had inverse effects. Furthermore, miR-4260 negatively regulated MCC as well as SMAD4 by directly binding to the 3'untranslational region (3'UTR). Using siRNAs targeting MCC or SMAD4, we showed that upregulation of MCC and SMAD4 was essential to mediate the functional roles of miR-4260 inhibitor in colorectal cancer cells. Our in vivo experiments indicated that inhibition of miR-4260 reduced colorectal tumor growth in nude mice subcutaneously implanted with HCT116 cells. Significantly, miR-4260 was increased in human colorectal cancer tissues with simultaneous downregulation of MCC and SMAD4, strongly suggesting the clinical relevance of targeting miR-4260 in the treatment of colorectal cancer. In summary, we identified miR-4260 as a novel oncomiR for colorectal cancer that targets MCC and SMAD4. Inhibition of miR-4260 can, therefore, be a potential therapeutic strategy for colorectal cancer.