The malignant property of circHIPK2 for angiogenesis and chemoresistance in non-small cell lung cancer

circHIPK2 promotes malignant progression of laryngeal squamous cell carcinoma through the miR-889-3p/MCTS1/IL-6 axis

Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumor of the head and neck with a poor prognosis. The role of circRNAs in LSCC remains largely unknown. In this study, quantitative real-time PCR (qRT-PCR), Sanger sequencing and fluorescence in situ hybridization were undertaken to detect the expression, localization, and clinical significance of circHIPK2 in LSCC tissues and TU686 and TU212 cells. The functions of circHIPK2 in LSCC were explored through proliferation analysis, EdU staining, colony formation assay, wound healing assay, and Transwell assay. The regulatory mechanisms underpinning circHIPK2, miR-889-3p, and MCTS1 were investigated using luciferase assay, Western blotting, and qRT-PCR. We found that LSCC tissues and cells demonstrated high expression of circHIPK2 that was closely associated with the malignant progression and poor prognosis of LSCC. Knockdown of circHIPK2 inhibited the proliferation and migration of LSCC cells in vitro. Mechanistic studies showed that circHIPK2 competitively bound to miR-889-3p, elevated MCTS1 level, promoted IL-6 secretion, and ultimately accelerated the malignant progression of LSCC. In conclusion, an axis involving circHIPK2, miR-889-3p, MCTS1 and IL-6 regulates the malignant progression of LSCC. circHIPK2 expression may serve as a novel diagnostic and prognostic biomarker for LSCC.

CircRNA regulates lung cancer metastasis

Lung cancer stands prominently among the foremost contributors to human mortality, distinguished by its elevated fatality rate and the second-highest incidence rate among malignancies. The metastatic dissemination of lung cancer stands as a primary determinant of its elevated mortality and recurrence rates, underscoring the imperative for comprehensive investigation into its metastatic pathways. Circular RNAs (circRNAs), a subclass of non-coding RNA (ncRNA) molecules, have garnered attention for their pivotal involvement in the genesis and advancement of lung cancer. Emerging evidence highlights the indispensable functions of circRNAs in orchestrating the metastatic cascade of lung cancer. This review primarily discusses the mechanisms by which circRNAs act as competitive endogenous RNAs (ceRNAs) and modulate various signaling pathways to regulate lung cancer metastasis. CircRNAs influence critical cellular processes including angiogenesis, autophagy, and glycolysis, thereby exerting influence over the metastatic cascade in lung cancer. These discoveries offer innovative perspectives and therapeutic avenues for the diagnosis and management of lung cancer.

EIF4A3-Induced Circ_0059914 Promoted Angiogenesis and EMT of Glioma via the miR-1249/VEGFA Pathway

Gliomas are common brain tumors. Despite extensive research, the 5-year survival rate of glioma remains low. Many studies have reported that circular RNAs (circRNAs) play a role in promoting the malignant progression of glioma; however, the role of circ_0059914 in this process remains unclear. In this study, we aimed to investigate the function and underlying mechanism of circ_0059914 in glioma. Western blotting and qRT-PCR were used to determine the levels of circ_0059914, miR-1249, VEGFA, N-cadherin, vimentin, Snail, and EIF4A3. EDU and colony formation assays were conducted to evaluate cell proliferation. Transwell assays were used to explore cell migration and invasion and tube formation assays were used to analyze angiogenesis. RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were used to explore the relationship between EIF4A3, circ_0059914, miR-1249, and VEGFA. A xenograft tumor assay was performed to determine the role of circ_0059914 in vivo. Circ_0059914 expression was upregulated in gliomas. Knockdown of gliomal circ_0059914 expression reduced the proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), angiogenesis, and growth of glioma cells in vivo. Circ_0059914 sponged miR-1249, and miR-1249 inhibition reversed the circ_0059914 knockdown-mediated effects in glioma cells. VEGFA was found to be a target gene of miR1249; overexpression of VEGFA reversed the effect of miR-1249 up-regulation in glioma. Finally, EIF4A3 increased the expression of circ_0059914. EIF4A3-induced circ_0059914 expression plays a role in promoting glioma via the miR-1249/VEGFA axis.

Circular RNAs in lung cancer: implications for preventing therapeutic resistance

LC is one of the most common malignant tumours that often presents with no distinct symptoms in the early stages, leading to late diagnoses when patients are at an advanced stage and no longer suitable for surgical treatment. Although adjuvant treatments are available, patients frequently develop tolerance to these treatments over time, resulting in poor prognoses for patients with advanced LC. Recently, circular RNAs (circRNAs), a type of non-coding RNA, have gained significant attention in LC research. Owing to their unique circular structure, circRNAs are highly stable within cells. This review systematically summarises the expression, characteristics, biological functions, and molecular regulatory mechanisms of circRNAs involved in therapy resistance as well as the potential applications in early diagnosis and gene targeting therapy in LC.

CircHIPK2 Contributes Cell Growth in Intestinal Epithelial of Colitis and Colorectal Cancer through Promoting TAZ Translation

Colorectal cancer (CRC) and inflammatory bowel disease (IBD) are escalating global health concerns. Despite their distinct clinical presentations, both disorders share intricate genetic and molecular interactions. The Hippo signaling pathway plays a crucial role in regulating cell processes and is implicated in the pathogenesis of IBD and CRC. Circular RNAs (circRNAs) have gained attention for their roles in various diseases, including IBD and CRC. However, a comprehensive understanding of specific circRNAs involved in both IBD and CRC, and their functional roles is lacking. Here, it is found that circHIPK2 (hsa_circRNA_104507) is a bona fide circRNA consistently upregulated in both IBD and CRC suggesting its potential as a biomarker. Furthermore, silencing of circHIPK2 suppressed the growth of CRC cells in vitro and in vivo. Interestingly, decreased circHipk2 potentiated dextran sulfate sodium (DSS)-induced colitis but alleviated colitis-associated tumorigenesis. Most significantly, mechanistic investigations further unveil that circHIPK2, mediated by FUS, interacting with EIF4A3 to promote the translation of TAZ, ultimately increasing the transcription of downstream target genes CCN1 and CCN2. Taken together, circHIPK2 emerges as a key player in the shared mechanisms of IBD and CRC, modulating the Hippo signaling pathway. CircHIPK2-EIF4A3 axis contributes to cell growth in intestinal epithelial of colitis and CRC by enhancing TAZ translation.

Circular RNA circHIPK2 inhibits colon cancer cells through miR-373-3p/RGMA axis

Circular RNAs (circRNAs) have been implicated in cancer development. However, their regulation, function, and underlying mechanisms of action remain unclear. We found that circHIPK2 was downregulated in colon cancer, and low expression levels of circHIPK2 were associated with high tumor grade and poor patient survival. The expression of circHIPK2 was observed to be regulated by the transcription factor HOXD10, which was downregulated in colon cancer. Consequently, low circHIPK2 expression promoted colon cancer cell proliferation, migration, and invasion in vitro and tumor growth and metastasis in vivo. Mechanistically, circHIPK2 sponges miR-373-3p to upregulate the expression of the tumor suppressor RGMA, leading to the activation of BMP/Smad signaling and, ultimately, the inhibition of colon cancer cells, indicating that circHIPK2 inhibits colon cancer cells through the miR-373-3p/RGMA/BMP pathway. These findings revealed a previously unknown regulation, function, and underlying mechanism of circHIPK2 in cancer cells. Hence, circHIPK2 may have a prognostic value and serve as a potential target for colon cancer treatment.

Deciphering the impact of circRNA-mediated autophagy on tumor therapeutic resistance: a novel perspective

Cancer therapeutic resistance remains a significant challenge in the pursuit of effective treatment strategies. Circular RNAs (circRNAs), a class of non-coding RNAs, have recently emerged as key regulators of various biological processes, including cancer progression and drug resistance. This review highlights the emerging role of circRNAs-mediated autophagy in cancer therapeutic resistance, a cellular process that plays a dual role in cancer by promoting both cell survival and death. Increasing evidence suggests that circRNAs can modulate autophagy pathways, thereby influencing the response of cancer cells to therapeutic agents. In this context, the intricate interplay between circRNAs, autophagy, and therapeutic resistance is explored. Various mechanisms are discussed through which circRNAs can impact autophagy, including direct interactions with autophagy-related genes, modulation of signaling pathways, and cross-talk with other non-coding RNAs. Furthermore, the review delves into specific examples of how circRNA-mediated autophagy regulation can contribute to resistance against chemotherapy and radiotherapy. Understanding these intricate molecular interactions provides valuable insights into potential strategies for overcoming therapeutic resistance in cancer. Exploiting circRNAs as therapeutic targets or utilizing them as diagnostic and predictive biomarkers opens new avenues for developing personalized treatment approaches. In summary, this review underscores the importance of circRNA-mediated autophagy in cancer therapeutic resistance and proposes future directions for research in this exciting and rapidly evolving field.

YTHDF2 alleviates microglia activation via promoting circHIPK2 degradation

Microglial activation is a common cellular dysfunction in central nervous system inflammation, accompanied by abnormal expression of circular RNAs (circRNAs). YTHDF2, a N6-methyladenosine (m6A) reader, is known as a key element in RNA degradation. Here, lipolysaccharide induced microglia activation in mouse cortex and BV2 cells, accompanied by the decreased YTHDF2 and elevated circHIPK2. YTHDF2 overexpression or circHIPK2 knockdown in BV2 microglia inhibited the expressions of iNOS protein, IL-1β mRNA and IL-6 mRNA. Subsequent experiments revealed that YTHDF2 facilitated circHIPK2 degradation, thereby alleviating microglia activation. These findings suggest that YTHDF2 overexpression could serve as a therapeutic approach for inhibiting microglia activation.

Regulation of Angiogenesis by Non-Coding RNAs in Cancer

Non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, have been identified as crucial regulators of various biological processes through epigenetic regulation, transcriptional regulation, and post-transcriptional regulation. Growing evidence suggests that dysregulation and activation of non-coding RNAs are closely associated with tumor angiogenesis, a process essential for tumor growth and metastasis and a major contributor to cancer-related mortality. Therefore, understanding the molecular mechanisms underlying tumor angiogenesis is of utmost importance. Numerous studies have documented the involvement of different types of non-coding RNAs in the regulation of angiogenesis. This review provides an overview of how non-coding RNAs regulate tumor angiogenesis. Additionally, we discuss emerging strategies that exploit non-coding RNAs for anti-angiogenic therapy in cancer treatment. Ultimately, this review underscores the crucial role played by non-coding RNAs in tumor angiogenesis and highlights their potential as therapeutic targets for anti-angiogenic interventions against cancer.

Hsa-microRNA-1249-3p/Homeobox A13 axis modulates the expression of β-catenin gene in human epithelial cells

Intercellular adhesion is a key function for epithelial cells. The fundamental mechanisms relying on epithelial cell adhesion have been partially uncovered. Hsa-microRNA-1249-3p (hsa-miR-1249-3p) plays a role in the epithelial mesenchymal transition in carcinoma cells, but its physiological function in epithelial cells is unknown. We aimed to investigate the role and molecular mechanisms of hsa-miR-1249-3p on epithelial cell functions. Hsa-miR-1249-3p was overexpressed in human epithelial cells and uterine cervical tissues, compared to cervical carcinoma cells and precancerous tissues, respectively. Hsa-miR-1249-3p was analyzed to verify its regulatory function on Homeobox A13 (HOXA13) target gene and its downstream cell adhesion gene β-catenin. Functional experiments indicated that hsa-miR-1249-3p inhibition prompted the mRNA and protein overexpression of HOXA13 which, in turn, led to the β-catenin protein expression. Moreover, hsa-miR-1249-3p inhibition induced a strong colony forming ability in epithelial cells, suggesting the miR involvement in cell adhesion machinery. These data indicate that hsa-miR-1249-3p regulates the expression of HOXA13 and its downstream cell adhesion gene β-catenin, possible resulting in cell adhesion modification in epithelial cells. This study will allow the set-up of further investigations aimed at exploring the relationship between the hsa-miR-1249-3p/HOXA13 axis and downstream cell adhesion genes.

Circular RNAs-mediated angiogenesis in human cancers

Circular RNAs (circRNAs) as small non-coding RNAs with cell, tissue, or organ-specific expression accomplish a broad array of functions in physiological and pathological processes such as cancer development. Angiogenesis, a complicated multistep process driving a formation of new blood vessels, speeds up tumor progression by supplying nutrients as well as energy. Abnormal expression of circRNAs reported to affect tumor development through impressing angiogenesis. Such impacts are introduced as constant with different tumorigenic features known as "hallmarks of cancer". In addition, deregulated circRNAs show possibilities to prognosis and diagnosis both in the prophecy of prognosis in malignancies and also their prejudice from healthy individuals. In the present review article, we have evaluated the angiogenic impacts and anti-angiogenic managements of circRNAs in human cancers.

Hsa_circ_0041150 serves as a novel biomarker for monitoring chemotherapy resistance in small cell lung cancer patients treated with a first-line chemotherapy regimen

PURPOSE

To explore the potential of circRNAs as biomarkers in non-invasive body fluids for monitoring chemotherapy resistance in SCLC patients.

METHODS

CircRNAs were screened and characterized using transcriptome sequencing, Sanger sequencing, actinomycin D treatment, and Ribonuclease R assay. Our study involved 174 participants, and serum samples were collected from all chemotherapy-resistant patients (n = 54) at two time points: stable disease and progressive disease. We isolated and identified serum extracellular vesicles (EVs) from the patients using ultracentrifugation, transmission electron microscopy, nanoflow cytometry, and western blotting analysis. The expression levels of serum and serum EVs circRNAs were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The impact of circRNA on the function of SCLC cells was assessed through various assays, including proliferation assay, scratch assay, transwell assay, and cisplatin resistance assay.

RESULTS

Hsa_circ_0041150 was found to be upregulated in chemoresistant SCLC cells and played a role in promoting proliferation, invasion, migration, and cisplatin resistance. Furthermore, the expression levels of hsa_circ_0041150 in serum and serum EVs increased when SCLC patients developed resistance after a first-line chemotherapy regimen. When combined with NSE, the monitoring sensitivity (70.37%) and specificity (81.48%) for chemotherapy resistance significantly improved. Moreover, the expression level of hsa_circ_0041150 showed significant associations with time to progression from SD to PD, and high hsa_circ_0041150 levels after drug resistance were more likely to cause chemotherapy resistance. Additionally, hsa_circ_0041150 demonstrated valuable potential in monitoring the progression from initial diagnosis to chemotherapy resistance in SCLC patients.

CONCLUSION

Thus, EVs hsa_circ_0041150 holds promise as a biomarker for monitoring chemotherapy resistance in SCLC patients.

CircRNAs and lung cancer: Insight into their roles in metastasis

Lung cancer is the leading cause of cancer-related mortality worldwide. A major contributing factor to the poor survival rates in lung cancer is the high prevalence of metastasis at the time of diagnosis. To address this critical issue, it is imperative to investigate the mechanisms underlying lung cancer metastasis. Circular RNAs (circRNAs), a distinct type of ribonucleic acid characterized by their unique circular structure, have been implicated in the progression of various diseases. Recent studies have highlighted the close association between circRNAs and the occurrence and development of lung cancer, particularly in relation to metastasis. In this review, we provide a concise overview of the expression patterns and prognostic significance of circRNAs in lung cancer. Additionally, we summarized the current understanding of the clinical relevance of circRNAs in lung cancer metastasis. Furthermore, we systematically focused on the roles of circRNAs in each step of lung cancer metastasis, reflecting the sequential progression of this process. Notably, circRNAs exhibit dual functionality in lung cancer metastasis, acting both as facilitators and inhibitors of metastatic processes. Given their potential, circRNAs hold promise as novel biomarkers and therapeutic targets for lung cancer metastasis, warranting further investigation.

Nanotechnology-empowered lung cancer therapy: From EMT role in cancer metastasis to application of nanoengineered structures for modulating growth and metastasis

Lung cancer is one of the leading causes of death in both males and females, and it is the first causes of cancer-related deaths. Chemotherapy, surgery and radiotherapy are conventional treatment of lung cancer and recently, immunotherapy has been also appeared as another therapeutic strategy for lung tumor. However, since previous treatments have not been successful in cancer therapy and improving prognosis and survival rate of lung tumor patients, new studies have focused on gene therapy and targeting underlying molecular pathways involved in lung cancer progression. Nanoparticles have been emerged in treatment of lung cancer that can mediate targeted delivery of drugs and genes. Nanoparticles protect drugs and genes against unexpected interactions in blood circulation and improve their circulation time. Nanoparticles can induce phototherapy in lung cancer ablation and mediating cell death. Nanoparticles can induce photothermal and photodynamic therapy in lung cancer. The nanostructures can impair metastasis of lung cancer and suppress EMT in improving drug sensitivity. Metastasis is one of the drawbacks observed in lung cancer that promotes migration of tumor cells and allows them to establish new colony in secondary site. EMT can occur in lung cancer and promotes tumor invasion. EMT is not certain to lung cancer and it can be observed in other human cancers, but since lung cancer has highest incidence rate, understanding EMT function in lung cancer is beneficial in improving prognosis of patients. EMT induction in lung cancer promotes tumor invasion and it can also lead to drug resistance and radio-resistance. Moreover, non-coding RNAs and pharmacological compounds can regulate EMT in lung cancer and EMT-TFs such as Twist and Slug are important modulators of lung cancer invasion that are discussed in current review.

HIPK2 in Angiogenesis: A Promising Biomarker in Cancer Progression and in Angiogenic Diseases

Angiogenesis is the formation of new blood capillaries taking place from preexisting functional vessels, a process that allows cells to cope with shortage of nutrients and low oxygen availability. Angiogenesis may be activated in several pathological diseases, from tumor growth and metastases formation to ischemic and inflammatory diseases. New insights into the mechanisms that regulate angiogenesis have been discovered in the last years, leading to the discovery of new therapeutic opportunities. However, in the case of cancer, their success may be limited by the occurrence of drug resistance, meaning that the road to optimize such treatments is still long. Homeodomain-interacting protein kinase 2 (HIPK2), a multifaceted protein that regulates different molecular pathways, is involved in the negative regulation of cancer growth, and may be considered a "bona fide" oncosuppressor molecule. In this review, we will discuss the emerging link between HIPK2 and angiogenesis and how the control of angiogenesis by HIPK2 impinges in the pathogenesis of several diseases, including cancer.