circ_0089153 exacerbates breast cancer cells proliferation and metastasis via sponging miR-2467-3p/E2F6

Circular RNAs in EMT-driven metastasis regulation: modulation of cancer cell plasticity, tumorigenesis and therapy resistance

The non-coding RNAs comprise a large part of human genome lack of capacity in encoding functional proteins. Among various members of non-coding RNAs, the circular RNAs (circRNAs) have been of importance in the pathogenesis of human diseases, especially cancer. The circRNAs have a unique closed loop structure and due to their stability, they are potential diagnostic and prognostic factors in cancer. The increasing evidences have highlighted the role of circRNAs in the modulation of proliferation and metastasis of cancer cells. On the other hand, metastasis has been responsible for up to 90% of cancer-related deaths in patients, requiring more investigation regarding the underlying mechanisms modulating this mechanism. EMT enhances metastasis and invasion of tumor cells, and can trigger resistance to therapy. The cells demonstrate dynamic changes during EMT including transformation from epithelial phenotype into mesenchymal phenotype and increase in N-cadherin and vimentin levels. The process of EMT is reversible and its reprogramming can disrupt the progression of tumor cells. The aim of current review is to understanding the interaction of circRNAs and EMT in human cancers and such interaction is beyond the regulation of cancer metastasis and can affect the response of tumor cells to chemotherapy and radiotherapy. The onco-suppressor circRNAs inhibit EMT, while the tumor-promoting circRNAs mediate EMT for acceleration of carcinogenesis. Moreover, the EMT-inducing transcription factors can be controlled by circRNAs in different human tumors.

Circular RNA-mediated miRNA sponge & RNA binding protein in biological modulation of breast cancer

Circular RNAs (circRNAs) and small non-coding RNAs of the head-to-junction circle in the construct play critical roles in gene regulation and are significantly associated with breast cancer (BC). Numerous circRNAs are potential cancer biomarkers that may be used for diagnosis and prognosis. Widespread expression of circRNAs is regarded as a feature of gene expression in highly diverged eukaryotes. Recent studies show that circRNAs have two main biological modulation models: sponging and RNA-binding. This review explained the biogenesis of circRNAs and assessed emerging findings on their sponge function and role as RNA-binding proteins (RBPs) to better understand how their interaction alters cellular function in BC. We focused on how sponges significantly affect the phenotype and progression of BC. We described how circRNAs exercise the translation functions in ribosomes. Furthermore, we reviewed recent studies on RBPs, and post-protein modifications influencing BC and provided a perspective on future research directions for treating BC.

Circular RNA and its potential diagnostic and therapeutic values in breast cancer

Breast cancer (BC) is one of the most common malignant tumors in women and still poses a significant threat to women worldwide. Recurrence of BC in situ, metastasis to distant organs, and resistance to chemotherapy are all attached to high mortality in patients with BC. Non-coding RNA (ncRNA) of the type known as "circRNA" links together from one end to another to create a covalently closed, single-stranded circular molecule. With characteristics including plurality, evolutionary conservation, stability, and particularity, they are extensively prevalent in various species and a range of human cells. CircRNAs are new and significant contributors to several kinds of disorders, including cardiovascular disease, multiple organ inflammatory responses and malignancies. Recent studies have shown that circRNAs play crucial roles in the occurrence of breast cancer by interacting with miRNAs to regulate gene expression at the transcriptional or post-transcriptional levels. CircRNAs offer the potential to be therapeutic targets for breast cancer treatment as well as prospective biomarkers for early diagnosis and prognosis of BC. Here, we are about to present an overview of the functions of circRNAs in the proliferation, invasion, migration, and resistance to medicines of breast cancer cells and serve as a promising resource for future investigations on the pathogenesis and therapeutic strategies.

Predictive role of E2F6 in cancer prognosis and responses of immunotherapy

BACKGROUND

E2F6 is a member of the E2F transcription factor family. Numerous studies have demonstrated that E2F6 is critical to cancer development and progression, but its role in cancer immunotherapy remains unclear.

METHODS

Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) databases were used to obtain RNA-seq data for cancer and normal tissues, and we utilized the cBioPortal to analyze E2F6 genomic alterations in pan-cancer. The protein localization of E2F6 was obtained using the Human Protein Atlas (HPA), and the upregulation of E2F6 expression in clinical glioblastoma multiforme (GBM) tissues was detected by Western blot analysis. The ComPPI website was used to analyze the protein interaction information of E2F6. To evaluate the role of E2F6 in pan-cancer prognosis, we used univariate Cox regression and Kaplan-Meier methods, and gene set enrichment analysis (GSEA) was utilized to identify markers associated with E2F6 expression in tumors. TIMER 2.0 was used to study E2F6-related immune cell infiltration in tumor tissues, and the correlation of E2F6 with immunotherapy biomarkers was investigated using Spearman correlation analysis. The role of E2F6 in the cell cycle was analyzed by flow cytometry, and the Cell Counting Kit-8 (CCK-8) and colony formation assays were utilized to determine the proliferative ability of cells.

RESULTS

In most tumor types, E2F6 was highly expressed and was a good predictor of prognosis. E2F6 was significantly related to markers of immune activation, tumor immune cell infiltration, and immune regulators. Furthermore, E2F6 knockdown significantly attenuated the proliferative ability of glioma cells. Finally, E2F6 effectively predicted anti-programmed cell death 1 (PD1) treatment response.

CONCLUSION

E2F6 is an effective biomarker that predicts the prognosis of cancer patients treated with anti-immune checkpoint therapy.

Screening microRNAs as potential prognostic biomarkers for lung adenocarcinoma

OBJECTIVE

To screen and identify microRNAs (miRNAs) associated with the prognosis of lung adenocarcinoma (LUAD) using clinical samples and construct a prediction model for the prognosis of LUAD.

METHODS

160 patient samples were used to screen and identify miRNAs associated with the prognosis of LUAD. Differentially expressed miRNAs were analyzed using gene chip technology. The selected miRNAs were validated using samples from the validation sample group. Cox proportional hazards regression was used to construct the model and Kaplan-Meier was used to plot survival curves. Model power was assessed by testing the prognosis of the constructed model using real-time polymerase chain reaction (RT-PCR) data.

RESULTS

The data showed that miR-1260b, miR-21-3p and miR-92a-3p were highly expressed in the early recurrence and metastasis group, while miR-2467-3p, miR-4659a-3p, miR-4514, miR-1471 and miR-3621 were lowly expressed. It was further confirmed that miR-21-3p was significantly highly expressed in the early recurrence and metastasis group (p = 0.02). Receiver operating characteristic (ROC) curve results showed cut-off point value of 0.0172, sensitivity of 88.2% and specificity of 100%. The predictive results of the constructed model were in good agreement with the actual prognosis of patients by using the validation sample test (Kappa = 0.426, p < 0.001), with a model sensitivity of 74.4%, a specificity of 68.3%, and an accuracy of 71.3%.

CONCLUSION

miRNAs associated with the prognosis of patients with stage I LUAD were screened and validated, and a risk model for predicting the prognosis of patients was constructed. This model has good consistency with the actual prognosis of patients.

Circular RNA nuclear receptor interacting protein 1 promoted biliary tract cancer epithelial-mesenchymal transition and stemness by regulating the miR-515-5p/AKT2 axis and PI3K/AKT/mTOR signaling pathway

Biliary tract cancer (BTC) is a devastating malignancy that is notoriously difficult to diagnose and is associated with high mortality. Circular RNA (circRNA) is a class of endogenous non-coding RNA which has been regarded as the key regulator of tumor initiation and progression, including BTC. Circular RNA nuclear receptor interacting protein 1 (circ_NRIP1), as a circular RNA, is abnormally expressed in many human tumors and exhibits diverse functions in cancer progression. However, its biological significance in BTC has not been thoroughly investigated. In this research, we elucidated that circ_NRIP1 was notably overexpressed in both BTC tissues and cells. We further established a correlation between circ_NRIP1 expression and clinicopathological features in BTC patients, highlighting its clinical relevance. Through functional assays, we observed that knockdown of circ_NRIP1 significantly inhibited tumor cell proliferation, invasion, stemness maintenance, and epithelial-mesenchymal transition, indicating its active involvement in promoting BTC progression. Additionally, it attenuated growth of xenograft and metastasis models. Mechanically, we revealed that circ_NRIP1 served as the competing endogenous RNA to sequester miR-515-5p through complementary base pairing mechanism, thereby upregulated AKT2 expression and indirectly activated PI3K/AKT/mTOR signaling pathway. Generally, targeting the circ_NRIP1/miR-515-5p/AKT2 axis and aberrant activation of the PI3K/AKT/mTOR pathway may hold promising therapeutic strategies for BTC. Our research contributes to a better understanding of the underlying biological basis of BTC and paves the way for the development of innovative treatment approaches.

c-JUN-induced upregulation of LINC00174 contributes to colorectal cancer proliferation and invasion through accelerating USP21 expression

Colorectal cancer (CRC) is one of the most common human malignancies due to its invasiveness and metastasis. Recent studies revealed the pivotal roles of long noncoding RNAs (lncRNAs) in tumorigenesis and progressions of various tumors. However, the biological roles and molecular mechanisms of long intergenic noncoding RNA 00174 (LINC00174) in human CRC remain unclear. Here, we report that LINC00174 expression was higher in human CRC tissues and cell lines than in adjacent normal tissues and a colon epithelial cell line (FHC). High expression of LINC00174 was positively correlated with poor overall and disease-free survival in patients with CRC. Loss- and gain-of-function of LINC00174 demonstrated its critical roles in promoting cell proliferation, apoptosis resistance, migration, and invasion of CRC cells in vitro. Moreover, overexpression of LINC00174 enhanced tumor growth in vivo. Mechanistic experiments revealed that LINC00174 could bind to microRNA (miR)-2467-3p and augment the expression and function of ubiquitin-specific peptidase 21 (USP21). Rescue assays found that miR-2467-3p inhibition can offset the actions of LINC00174 or USP21 knockdown in CRC cells. Additionally, transcriptional factor c-JUN transcriptionally activated LINC00174 expression and mediated LINC00174-induced malignant phenotypes of CRC cell lines. Totally, our findings shed light on a new therapeutic strategy in modulating LINC00174/miR-2467-3p, which may interfere with the expression of USP21, and revealed that LINC00174 could be a new therapeutic target or prognostic marker in CRC.

Tumor-associated macrophages-derived exo-let-7a promotes osteosarcoma metastasis via targeting C15orf41 in osteosarcoma

BACKGROUND

Osteosarcoma (OS) immune environment is complexed and the immune factors-related to OS progression need to be explored. Tumor-associated macrophages (TAMs) are regarded as immune suppressive and tumor-promoting cells. However, the underlying mechanisms through which TAMs function are still fragmentary. Here, we aim to explore the underlying mechanisms by which TAMs regulate OS progression.

METHODS

TAMs from OS tissues were isolated by flow cytometry. Exosomes derived from TAMs were separated using ultracentrifugation and western blotting. Transmission electron microscopy (TEM), and flow cytometry were constructed to characterize TAMs-derived exosomes. Additionally, the differential MicroRNAs (miRNAs) and genes were detected through RNA sequencing, and further validated using real-time PCR (RT-PCR). OS cell metastasis ability was assessed using transwell invasion and scratch wound healing assays. MiRNAs mimic and lentiviral vectors were utilized to explore the effects on OS progression.

RESULTS

Exosome secreted by TAMs accelerated the OS metastasis. Let-7a level was upregulated in TAMs derived exosomes, which downregulated C15orf41 by targeting 3'-untranslated region (UTR). Furthermore, overexpressing let-7a enhanced invasion and migration by blocking the transcription of C15orf41. In consistent, up-regulating let-7a promoted OS progression and made the prognosis to be worse, which can be reversed by C15orf41 overexpression.

CONCLUSION

This study highlighted the critical role of TAMs-derived exosomes in OS progression and explored the potential value of the let-7a/C15orf41 axis as an indicator or target for OS.

Hsa_circ_0003528 promotes cell malignant transformation and immune escape via increasing oncogene PDL1 through sponging miR-511-3p in non-small cell lung cancer

BACKGROUND

Accumulating evidence suggests that circular RNAs (circRNAs) play important regulatory roles in non-small cell lung cancer (NSCLC). At present, we aimed to explore the regulatory role of has_circ_0003528 (circ_0003528) in NSCLC.

METHODS

Alterations of circ_0003528 expression in NSCLC samples and cell lines were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Impacts of circ_0003528 on NSCLC cell malignant transformation were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell invasion, and tube formation assays. Epithelial-mesenchymal transition (EMT)-related markers were detected with western blotting. Pro-inflammatory cytokines were detected by Enzyme-linked immunosorbent assay (ELISA). The regulation mechanism of circ_0003528 was verified by dual-luciferase reporter and RNA pull-down assays. The tumorigenesis role of circ_0003528 was verified by animal experiments.

RESULTS

Higher levels of circ_0003528 were obtained in NSCLC samples and cell lines, and patients with high circ_0003528 expression had a worse prognosis. Silence of circ_0003528 decreased xenograft growth in mouse models and induced cell apoptosis and repressed cell viability, proliferation, invasion, EMT, angiogenesis, and immune escape in NSCLC cells in vitro. Mechanistically, circ_0003528 controlled programmed cell death ligand 1 (PDL1) expression through interaction with miR-511-3p. The inhibiting impacts of circ_0003528 knockdown on NSCLC cell malignant transformation and immune escape were weakened after miR-511-3p silencing. Moreover, PDL1 overexpression partially counteracted miR-511-3p upregulation-mediated suppression on NSCLC cell malignant transformation and immune escape.

CONCLUSIONS

Circ_0003528 facilitated NSCLC cell malignant transformation and immune escape through regulation of the miR-511-3p/PDL1 axis, highlighting the oncogenic role of circ_0003528 in NSCLC.

The pan-cancer analysis of the oncogenic role of FAM72A as a BRCA prognostic biomarker and immunotherapeutic target

In this study, we first comprehensively investigated the expression profile, mutation status, and survival analysis of FAM72A as well as the correlation between FAM72A and DNA damage repair, methylation, and cell stemness analysis using bioinformatics techniques. In addition, we also analyzed the relationship between FAM72A and immune cell infiltration and pathway enrichment. The role of FAM72A in breast cancer (BC) was so conspicuous that we analyzed the prognostic significance and clinicopathological parameter's relevance of FAM72A in BC. We also validated biological functions by applying in vitro experiments. FAM72A was highly expressed in 26 types of a total of 31 cancers, while it expressed low levels in only five cancers. FAM72A expression was relative to clinical stages in nine cancers and has a significant difference in disease-free survival among 31 kinds of cancers. In addition, FAM72A has negatively correlated with cancer-associated fibroblast and endothelial cells in BC but positively correlated with follicular helper T cells. Univariate and multivariate cox regression analyses identified T, N, M, age, and FAM72A expression as independent influences on BC prognosis, so we created a nomogram to predict patient survival benefits. In in vitro experiments, we verified that downregulation of FAM72A not only inhibited cell proliferation, colony formation, cell migration, cell invasion, and G2/M cell cycle transition but also promoted apoptosis of breast invasive carcinoma cells. Our study discovered FAM72A as a clinically meaningful biomarker for prognostic predicting and a guiding target for immune treatment in BC.

Circular forms of dedicator of cytokinesis 1 promotes breast cancer progression by derepressing never in mitosis related kinase 2 via sponging miR-128-3p

The conjecture of breast cancer is uncertain because of its explosive growth and the complicated molecular mechanisms. Circular RNAs (circRNAs) are regulatory RNA sequences present in the genome and their regulatory mechanism involves the sponging of microRNAs (miRNAs). In this study, we explored the regulation between circular forms of dedicator of cytokinesis 1 (circDOCK1) (hsa_circ_0007142) and miR-128-3p, and its implication on the pathogenesis of breast cancer modulated by never in mitosis (NIMA) related kinase 2 (NEK2). We revealed an increase in circDOCK1 and NEK2 expression, and a decrease in miR-128-3p expression in breast cancer tissues and cell lines. Bioinformatics analysis and experimental validation indicated a positive correlation between circDOCK1 and NEK2 expression but a negative correlation was recorded between miR-128-3p and circDOCK1 or NEK2, respectively. Furthermore, inhibition of circDOCK1 expression was followed by an increase in miR-128-3p and a decrease in NEK2 levels in vitro and in vivo. The luciferase assay concluded that miR-128-3p was a direct target of circDOCK1 while NEK2 was the direct target of miR-128-3p. Furthermore, circDOCK1 inhibition hindered breast cancer development by repressing NEK2 and thus promoting the increased expression of miR-128-3p both in vitro and in vivo. We therefore conclude that circDOCK1 promotes breast cancer progression by targeting miR-128-3p-mediated downregulation of NEK2 and that the circDOCK1/hsa-miR-128-3p/NEK2 axis may be a novel therapeutic target for breast cancer treatment.

Crocin suppresses breast cancer cell proliferation by down-regulating tumor promoter miR-122-5p and up-regulating tumor suppressors FOXP2 and SPRY2

Crocin has been reported to have antitumor activity in several tumors including breast cancer. Nevertheless, the mechanism of action of crocin on breast cancer remains unclear. The cytotoxicity of crocin was evaluated by CCK-8 assay. Cell proliferation was assessed using EdU incorporation assay and western blot analysis. Breast cancer-related genes were extracted from GEPIA. miR-122-5p targets were predicted using Targetscan, starbase, and miRDB softwares. Luciferase reporter assay was employed to confirm whether miR-122-5p targeted sprouty2 (SPRY2) and forkhead box P2 (FOXP2). Results showed that crocin exhibited cytotoxicity and suppressed the proliferation in breast cancer cells. miR-122-5p was upregulated in breast cancer tissues and cells. Crocin suppressed miR-122-5p to block the proliferation of breast cancer cells. Seven targets of miR-122-5p were identified in breast cancer. SPRY2 and FOXP2 were selected for further experiments due to their involvement in breast cancer. miR-122-5p targeted SPRY2 and FOXP2 to inhibit their expression. miR-122-5p knockdown restrained breast cancer cell proliferation by targeting SPRY2 and FOXP2. Additionally, crocin increased SPRY2 and FOXP2 expression by inhibiting miR-122-5p expression. Together, our results suggested that crocin inhibited proliferation of breast cancer cells through decreasing miR-122-5p expression and the subsequent increase of SPRY2 and FOXP2 expression.

Critical Roles of Circular RNA in Tumor Metastasis via Acting as a Sponge of miRNA/isomiR

Circular RNAs (circRNAs), a class of new endogenous non-coding RNAs (ncRNAs), are closely related to the carcinogenic process and play a critical role in tumor metastasis. CircRNAs can lay the foundation for tumor metastasis via promoting tumor angiogenesis, make tumor cells gain the ability of migration and invasion by regulating epithelial-mesenchymal transition (EMT), interact with immune cells, cytokines, chemokines, and other non-cellular components in the tumor microenvironment, damage the normal immune function or escape the immunosuppressive network, and further promote cell survival and metastasis. Herein, based on the characteristics and biological functions of circRNA, we elaborated on the effect of circRNA via circRNA-associated competing endogenous RNA (ceRNA) network by acting as miRNA/isomiR sponges on tumor angiogenesis, cancer cell migration and invasion, and interaction with the tumor microenvironment (TME), then explored the potential interactions across different RNAs, and finally discussed the potential clinical value and application as a promising biomarker. These results provide a theoretical basis for the further application of metastasis-related circRNAs in cancer treatment. In summary, we briefly summarize the diverse roles of a circRNA-associated ceRNA network in cancer metastasis and the potential clinical application, especially the interaction of circRNA and miRNA/isomiR, which may complicate the RNA regulatory network and which will contribute to a novel insight into circRNA in the future.

Multifunctional photodynamic/photothermal nano-agents for the treatment of oral leukoplakia

Oral leukoplakia (OLK) has gained extensive attention because of the potential risk for malignant transformation. Photosensitizers (PSs) played an indispensable role in the photodynamic therapy (PDT) of OLK, but the poor light sensitivity greatly hampered its clinical application. Herein, a novel organic photosensitive ITIC-Th nanoparticles (ITIC-Th NPs) were developed for OLK photodynamic/photothermal therapy (PTT). ITIC-Th NPs present both high photothermal conversion efficiency (~ 38%) and suitable reactive oxygen species (ROS) generation ability under 660 nm laser irradiation, making them possess excellent PDT and PTT capability. In 4-nitroquinoline 1-oxide (4NQO)-induced oral precancerous animal models, ITIC-Th NPs effectively suppress the OLK's cancerization without apparent topical or systemic toxicity in vivo. This study offers a promising therapeutic strategy for PDT and PTT in OLK treatment, and this study is the first interdisciplinary research in the field of multimodal therapy for OLK.