IL-6-induced cGGNBP2 encodes a protein to promote cell growth and metastasis in intrahepatic cholangiocarcinoma

CircRNA encoded-peptide: Potential stock in the transcriptomics market

The emergence of circRNA-encoded peptides has sparked significant debate in recent years as a novel mode of action for circRNAs. A mounting body of evidence suggests that these peptides play vital roles in cancer development and immune responses. This review initially elucidates the presence of circRNA-encoded peptides and delineates their specific functions across various biological processes and pathological conditions. It goes on to furnish illustrative instances to underscore the pivotal involvement of circRNA-encoded peptides in both innate and adaptive immune responses. The study sheds new light on the biological roles of circRNAs, their potential tumor-promoting and tumor-suppressing functions of circRNA-encoded peptides in specific tumor environment, and their significance in immunological contexts. Meanwhile, the limitations of existing studies on circRNA-encoded peptides are discussed in depth. In particular, circRNA-encoded peptides are critically analyzed as biomarkers and therapeutic targets. Intriguingly, the review concludes with a more organized discussion of future research on circRNA-encoded peptides.

Insights into Sorafenib resistance in hepatocellular carcinoma: Mechanisms and therapeutic aspects

The most prevalent primary hepatic cancer, hepatocellular carcinoma (HCC), has a bad prognosis. HCC prevalence and related deaths have increased in recent decades. Food and Drug Administration (FDA) has licensed Sorafenib as a first-line treatment for individuals with advanced HCC. Despite this, some clinical studies indicate that a significant percentage of liver cancer patients exhibit insensitivity to sorafenib. Furthermore, the overall effectiveness of sorafenib is far from adequate, and the number of patients who benefit from therapy is low. In recent years, many researchers have focused on the mechanisms underlying sorafenib resistance. Acquired resistance to sorafenib in HCC cells has been reported to be facilitated by dysregulation of signal transducer and activator of transcription 3 (STAT3) activation, angiogenesis, autophagy, hypoxia-induced pathways, epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), ferroptosis, and non-coding RNAs (ncRNAs). Recent clinical trials, including comparisons of sorafenib with immune checkpoint inhibitors like tislelizumab, have shown promise in improving patient outcomes. Additionally, combination therapies targeting complementary pathways are under investigation to overcome resistance and enhance treatment efficacy. The limitation of Sorafenib's effectiveness has been partially but not completely clarified. Furthermore, while certain regimens have demonstrated positive results, more clinical trials are required to confirm them. Future research should focus on identifying predictive biomarkers for therapy response, targeting the tumor microenvironment, and exploring novel therapeutic agents and personalized medicine strategies. A deeper understanding of these mechanisms will be essential for developing more effective therapeutic approaches and improving the prognosis of patients with advanced HCC. This article discusses strategies that may be employed to enhance the success of treatment and summarizes new research on the possible pathways that lead to sorafenib resistance.

The role of circular RNAs in regulating cytokine signaling in cancer

Dysregulation of cytokine signaling is central to the development and progression of cancer. Cytokines are not only involved in promoting cancer development but also regulate anti-tumor immune responses. Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules lacking free ends, which have emerged as critical regulators of cytokine signaling. Transcriptional and post-transcriptional regulation of cytokine signaling by circRNAs contributes to cancer pathogenesis. Here, we discuss the emerging role of circRNAs in modulating cytokine signaling pathways that regulate cancer development. In particular, we examine the role of circRNAs in TGF-β, IL-6, IL-10, TNF-α, VEGF, FGF, PDGF, and chemokine signaling in cancer.

Coding circular RNA in human cancer

circular RNA (circRNA) is a covalently closed single-stranded RNA that lacks 5' and 3' ends and has long been considered a noncoding RNA. With the development of high-throughput sequencing and bioinformatics technology, the understanding of circRNA has become increasingly advanced. Recent studies have shown that some cytoplasmic circRNAs can be effectively translated into detectable proteins, further indicating the importance of circRNA in cellular pathology and physiological functions. Internal ribosome entry site (IRES) and N6-methyladenosine (m6A) mediated cap-independent translation initiation are considered potential mechanisms of circRNA translation. Multiple circRNAs have been shown to play crucial roles in human cancer. This paper provides an overview of the nature and functions of circRNA and describes the possible mechanisms underlying the initiation of circRNA translation. We summarized the emerging functions of circRNA-encoded proteins in human cancer. Finally, we discuss the therapeutic potential of circRNAs and the challenges of research in this field. This review on circRNA translation will reveal a hidden human proteome and enhance our understanding of the importance of circRNAs in human malignant tumors.

Biomarkers and Management of Cholangiocarcinoma: Unveiling New Horizons for Precision Therapy

Cholangiocarcinoma (CCA) is an aggressive malignancy with limited methods for early detection, necessitating the development of reliable biomarkers for diagnosis and management. However, conventional tumor markers, such as CA19-9 and CEA, exhibit insufficient diagnostic accuracy. Recent advancements in molecular genetics have identified several actionable mutations in CCA, enabling molecularly targeted therapies that improve survival in patients harboring these genetic alterations. Cancer panels, which facilitate multiplex genetic profiling, are critical for identifying these mutations. Studies indicate that several actionable mutations are detected in CCA cases, with patients receiving mutation-guided therapies achieving markedly better outcomes. Liquid biopsies, including cell-free DNA and circulating tumor DNA, offer real-time, non-invasive approaches to monitoring tumor dynamics, heterogeneity, and treatment responses. Furthermore, numerous studies have identified non-coding RNAs in serum and bile as promising biomarkers for the diagnosis and management of CCA. On the other hand, immunotherapy, particularly immune checkpoint inhibitors, has shown efficacy in subsets of CCA patients. However, the success of these therapies is often affected by the status of the tumor immune microenvironment (TME), underscoring the need for comprehensive TME analysis to predict responses to immune checkpoint inhibitors. Despite these advances, no single biomarker currently demonstrates sufficient sensitivity or specificity for clinical application. The integration of multi-omics approaches with cutting-edge technologies holds promise for enhancing diagnostic accuracy, optimizing treatment stratification, and advancing precision medicine in CCA. These developments highlight the transformative potential of biomarkers to improve early detection, prognostic assessment, and personalized therapeutic interventions for CCA.

Small open reading frame-encoded microproteins in cancer: identification, biological functions and clinical significance

The human genome harbors approximately twenty thousand protein-coding genes, and a significant portion of life science research focuses on elucidating their functions and the underlying mechanisms. Recent studies have revealed that small open reading frame (sORF), originating from non-coding RNAs or the 5' leader sequences of messenger RNAs, can be translated into small peptides called microproteins through cap-dependent or cap-independent mechanisms. These microproteins interact with diverse molecular partners to modulate gene expression at multiple regulatory levels, thereby playing critical roles in various biological processes. Notably, sORF-encoded microproteins exhibit aberrant expression patterns in cancer and are implicated in tumor initiation and progression, expanding our understanding of cancer biology. In this review, we introduce the translational mechanisms and identification methods of microproteins, summarize their dysregulation in cancer and their biological functions in regulating gene expression, and emphasize their roles in driving hallmark events of cancer. Furthermore, we discuss their clinical significance as diagnostic and prognostic biomarkers, as well as therapeutic targets.

Geriatric nutritional risk index and body composition dictate the prognosis of elderly patients with intrahepatic cholangiocarcinoma

Background and aims

Malnutrition is a well-recognized predictor of poor prognosis in malignancies. Recent studies suggest that the geriatric nutritional risk index (GNRI) is a more accurate determinant of prognosis in elderly patients than conventional body mass index (BMI). This study aimed to evaluate the GNRI and body composition parameters in elderly patients with intrahepatic cholangiocarcinoma (ICC) and assess their prognostic impact on long-term outcomes.

Methods

A total of 157 elderly ICC patients (aged ≥65 years) who underwent radical resection between 2009 and 2018 were retrospectively analyzed. Skeletal muscle index (SMI), muscle attenuation (MA), visceral adipose tissue index (VATI), subcutaneous adipose tissue index (SATI), and visceral-to-subcutaneous fat ratio (VSR) were quantified using computed tomography. Prognostic analyses were conducted using the Kaplan-Meier method, with adjustments using inverse probability weighting. A nomogram based on multivariate Cox regression was constructed and internally validated, comparing its prognostic accuracy with the TNM staging system.

Results

Among the body composition parameters, low SMI (sarcopenia, 56.1%), high VSR (visceral adiposity, 54.8%), and low MA (intramuscular fat deposition, 50.3%) were significantly associated with overall survival (OS) and recurrence-free survival (RFS) (all p < 0.05). Low GNRI was also a strong predictor of poor prognosis (p < 0.001). Multivariate analysis identified low GNRI (p = 0.009), sarcopenia (p = 0.020), visceral adiposity (p = 0.033), and intramuscular fat deposition (p = 0.036) as independent prognostic factors for OS and RFS. The nomogram, incorporating GNRI, SMI, VSR, MA, microvascular invasion (MVI), CA19-9 levels, and lymph node invasion, demonstrated superior prognostic performance compared to the TNM stage, with a C-index of 0.734 (OS) and 0.704 (RFS) and an AUC of 0.809 (OS) and 0.815 (RFS).

Conclusion

GNRI, sarcopenia, IMF deposition, and visceral adiposity independently predict mortality and tumor recurrence in elderly ICC patients. Body composition is a major determinant of prognosis in patients with ICC. Our nomogram based on body composition reveals superior prognostic efficacy over TNM stages.

NGR-Modified CAF-Derived exos Targeting Tumor Vasculature to Induce Ferroptosis and Overcome Chemoresistance in Osteosarcoma

Osteosarcoma (OS) chemoresistance presents a significant clinical challenge. This study aims to investigate the potential of using tumor vascular-targeting peptide NGR-modified cancer-associated fibroblasts (CAFs)-derived exosomes (exos) to deliver circ_0004872-encoded small peptides promoting autophagy-dependent ferroptosis to reverse chemoresistance in OS. Through combined single-cell transcriptome analysis and high-throughput sequencing, it identified circ_0004872 associated with chemoresistance. Subsequent experiments demonstrated that the small peptide encoded by this Circular RNA (circRNA) can effectively reverse chemoresistance by enhancing OS cell sensitivity to chemotherapy via the mechanism of promoting autophagy-dependent ferroptosis. Moreover, in vitro and in vivo results confirmed the efficient delivery of NGR-modified CAFs-derived exo-packaged circ_0004872-109aa to tumor cells, thereby improving targeted therapy efficacy. This study not only offers a novel strategy to overcome chemoresistance in OS but also highlights the potential application value of utilizing exos for drug delivery.

CircFak promotes mechanical force-induced osteogenesis via FAK/AKT phosphorylation

OBJECTIVES

Orthodontic treatment is widely applied for addressing orofacial skeletal deformities, with the remodeling of the alveolar bone under mechanical force being the key factor. FAK is essential for cellular response to mechanical force. However, the function of circFak has never been reported. In this study, the microarrays showed that circFak may affect osteogenesis under mechanical force. We aimed to verify the effect of circFak in force-related bone remodeling and investigate the underlying mechanisms.

METHODS

Arraystar microarrays were used to identify differentially expressed circRNAs and microRNAs in response to mechanical stress. The subcellular distribution of circFak was analyzed via RT‒qPCR and FISH. ALP and ARS staining assays were performed to investigate the effects of circFak on osteogenesis. RNA sequencing, bioinformatics analysis, dual-luciferase reporter assays, and RNA immunoprecipitation were accomplished to discover the molecular mechanisms of circFak. AAV-sh-circFak mouse models with tooth movements were established. The role of circFak under mechanical force in vivo was assessed via immunofluorescence and micro-CT analyses.

RESULTS

CircFak expression was significantly upregulated under mechanical force. Osteogenic capacity of osteoblasts was positively correlated with the level of circFak. CircFak promoted mechanical force-induced osteogenesis through miR-425-5p/Ccn3 pathway, and further stimulated the phosphorylation of its parental sourced protein FAK. Our murine models showed that AAV-mediated circFak silencing suppressed osteogenesis.

CONCLUSION

CircFak could obviously promote osteogenesis under mechanical force and may possess ability to become a novel biomarker for prognosis of orthodontic treatments.

Circular RNA in Pancreatic Cancer: Biogenesis, Mechanism, Function and Clinical Application

Circular RNAs (circRNAs) are a class of novel RNA molecules featured by single-strand covalently closed circular structure, which not only are extensively found in eukaryotes and are highly conserved, but also conduct paramount roles in the occurrence and progression of pancreatic cancer (PC) through diverse mechanisms. As recent studies have demonstrated, circRNAs typically exhibit tissue-specific and cell specific expression patterns, with strong potential as biomarkers for disease diagnosis and prognosis. On the basis of their localization and specific interactions with DNA, RNA, and proteins, circRNAs are considered to possess specific biological functions by acting as microRNA (miRNA) sponges, RNA binding protein (RBP) sponges, transcriptional regulators, molecular scaffolds and translation templates. On that account, further addressing the technical difficulties in the detection and research of circRNAs and filling gaps in their biological knowledge will definitely push ahead this comparatively young research field and bring circRNAs to the forefront of clinical practice. Thus, this review systematically summarizes the biogenesis, function, molecular mechanisms, biomarkers and therapeutic targets of circRNAs in PC.

Noncoding RNA-encoded peptides in cancer: biological functions, posttranslational modifications and therapeutic potential

In the present era, noncoding RNAs (ncRNAs) have become a subject of considerable scientific interest, with peptides encoded by ncRNAs representing a particularly promising avenue of investigation. The identification of ncRNA-encoded peptides in human cancers is increasing. These peptides regulate cancer progression through multiple molecular mechanisms. Here, we delineate the patterns of diverse ncRNA-encoded peptides and provide a synopsis of the methodologies employed for the identification of ncRNAs that possess the capacity to encode these peptides. Furthermore, we discuss the impacts of ncRNA-encoded peptides on the biological behavior of cancer cells and the underlying molecular mechanisms. In conclusion, we describe the prospects of ncRNA-encoded peptides in cancer and the challenges that need to be overcome.

Reversing NK cell exhaustion: a novel strategy combining immune checkpoint blockade with drug sensitivity enhancement in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common lethal cancers worldwide. Natural killer cells (NK cells) play a key role in liver immunosurveillance, but in the tumor microenvironment, NK cells are readily depleted, as evidenced by down-regulation of activating receptors, reduced cytokine secretion, and attenuated killing function. The up-regulation of inhibitory receptors, such as PD-1, TIM-3, and LAG-3, further exacerbates the depletion of NK cells. Combined blockade strategies targeting these immunosuppressive mechanisms, such as the combination of PD-1 inhibitors with other inhibitory pathways (eg. TIM-3 and LAG-3), have shown potential to reverse NK cell exhaustion in preclinical studies. This article explores the promise of these innovative strategies in HCC immunotherapy, providing new therapeutic directions for optimizing NK cell function and improving drug sensitivity.

CICADA: a circRNA effort toward the ghost proteome

Recent studies have confirmed that certain circRNAs encode proteins that are integral to various biological functions. In this study, we present CICADA, an algorithm specifically designed to assess the protein-coding potential and coding products of circRNAs at high throughput, which enables the identification of previously unknown circRNA-encoded proteins. By harnessing the potential of this algorithm, we identified a variety of functional, protein-coding circRNAs in esophageal squamous cell carcinoma and established circRNA translation profiles for diverse types of cancer. This advancement innovatively explores the hidden proteome within the genome, poised to catalyze discoveries in biomarkers and therapies for cancers and complex diseases. CICADA is accessible as a Python module (https://github.com/SunLab-biotool/CICADA).

The protein circPETH-147aa regulates metabolic reprogramming in hepatocellular carcinoma cells to remodel immunosuppressive microenvironment

Metabolic reprogramming fuels cancer cell metastasis and remodels the immunosuppressive tumor microenvironment (TME). We report here that circPETH, a circular RNA (circRNA) transported via extracellular vesicles (EVs) from tumor-associated macrophages (TAMs) to hepatocellular carcinoma (HCC) cells, facilitates glycolysis and metastasis in recipient HCC cells. Mechanistically, circPETH-147aa, encoded by circPETH in an m6A-driven manner, promotes PKM2-catalyzed ALDOA-S36 phosphorylation via the MEG pocket. Furthermore, circPETH-147aa impairs anti-HCC immunity by increasing HuR-dependent SLC43A2 mRNA stability and driving methionine and leucine deficiency in cytotoxic CD8+ T cells. Importantly, through virtual and experimental screening, we find that a small molecule, Norathyriol, is an effective inhibitor that targets the MEG pocket on the circPETH-147aa surface. Norathyriol reverses circPETH-147aa-facilitated acquisition of metabolic and metastatic phenotypes by HCC cells, increases anti-PD1 efficacy, and enhances cytotoxic CD8+ T-cell function. Here we show that Norathyriol is a promising anti-HCC agent that contributes to attenuating the resistance of advanced HCC to immune checkpoint blocker (ICB) therapies.

Crosstalk between circular RNAs and the STAT3 signaling pathway in human cancer

Circular RNAs (circRNAs) are endogenous covalently closed single-stranded RNAs produced by reverse splicing of pre-mRNA. Emerging evidence suggests that circRNAs contribute to cancer progression by modulating the oncogenic STAT3 signaling pathway, which plays key roles in human malignancies. STAT3 signaling-related circRNAs expression appears to be extensively dysregulated in diverse cancer types, where they function either as tumor suppressors or oncogenes. However, the biological effects of STAT3 signaling-related circRNAs and their associations with cancer have not been systematically studied before. Given this, shedding light on the interaction between circRNAs and STAT3 signaling pathway in human malignancies may provide several novel insights into cancer therapy. In this review, we provide a comprehensive introduction to the molecular mechanisms by which circRNAs regulate STAT3 signaling in cancer progression, and the crosstalk between STAT3 signaling-related circRNAs and other signaling pathways. We also further discuss the role of the circRNA/STAT3 axis in cancer chemotherapy sensitivity.

Interplay between JAK/STAT pathway and non-coding RNAs in different cancers

Progress in the identification of core multi-protein modules within JAK/STAT pathway has enabled researchers to develop a better understanding of the linchpin role of deregulated signaling cascade in carcinogenesis and metastasis. More excitingly, complex interplay between JAK/STAT pathway and non-coding RNAs has been shown to reprogramme the outcome of signaling cascade and modulate immunological responses within tumor microenvironment. Wealth of information has comprehensively illustrated that most of this complexity regulates the re-shaping of the immunological responses. Increasingly sophisticated mechanistic insights have illuminated fundamental role of STAT-signaling in polarization of macrophages to M2 phenotype that promotes disease aggressiveness. Overall, JAK/STAT signaling drives different stages of cancer ranging from cancer metastasis to the reshaping of the tumor microenvironment. JAK/STAT signaling has also been found to play role in the regulation of infiltration and activity of natural killer cells and CD4/CD8 cells by PD-L1/PD-1 signaling. In this review, we have attempted to set spotlight on regulation of JAK/STAT pathway by microRNAs, long non-coding RNAs and circular RNAs in primary tumors and metastasizing tumors. Therefore, existing knowledge gaps need to be addressed to propel this fledgling field of research to the forefront and bring lncRNAs and circRNAs to the frontline of clinical practice. Leveraging the growing momentum will enable interdisciplinary researchers to gain transition from segmented view to a fairly detailed conceptual continuum.

The Prognostic Values of Serum Liver Enzymes in Intrahepatic Cholangiocarcinoma Patients After Liver Resection: A Multi-Institutional Analysis of 605 Patients

Purpose

The value of liver enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT), in predicting the prognosis of intrahepatic cholangiocarcinoma (ICC) patients who underwent curative resection has not been elucidated. Therefore, we aimed to construct prognostic nomograms for surgically treated ICC patients.

Methods

The impact of liver enzymes on overall survival (OS) and recurrence-free survival (RFS) was analysed using Kaplan-Meier analysis and evaluated by univariate and multivariate analyses. Nomograms were constructed for predicting the probability of 1-, 3-, and 5-year OS and RFS and evaluated by receiver operating characteristic (ROC) curves, calibration curves and decision curve analysis (DCA).

Results

High ALT, AST, ALP and GGT levels were associated with worse prognoses in surgically treated ICC patients. Nomograms for OS and RFS were constructed based on five prognostic factors: number of high liver enzyme (No. HLE), CA19-9 ≥ 37 U/mL, multiple tumours, lymph node invasion and microvascular invasion (MVI). Compared with 8th edition TNM stage, these nomograms showed better predictive value. The C-index and 1-, 3- and 5-year areas under the curve (AUCs) of the nomograms for OS and RFS in the discovery and validation cohorts were higher than those of the 8th TNM stage. The calibration plots indicated that there was good agreement between the actual observations and predictions.

Conclusion

Preoperative ALT, AST, ALP and GGT levels could predict prognosis in surgically treated ICC patients. The nomograms showed good predictive ability for predicting the survival of ICC patients.

A literature review on signaling pathways of cervical cancer cell death-apoptosis induced by Traditional Chinese Medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Cervical cancer (CC) is a potentially lethal disorder that can have serious consequences for a woman's health. Because early symptoms are typically only present in the middle to late stages of the disease, clinical diagnosis and treatment can be challenging. Traditional Chinese medicine (TCM) has been shown to have unique benefits in terms of alleviating cancer clinical symptoms, lowering the risk of recurrence after surgery, and reducing toxic side effects and medication resistance after radiation therapy. It has also been shown to improve the quality of life for patients. Because of its improved anti-tumor effectiveness and biosafety, it could be considered an alternative therapy option. This study examines how TCM causes apoptosis in CC cells via signal transduction, including the active components and medicinal tonics. It also intends to provide a reliable clinical basis and protocol selection for the TCM therapy of CC.

METHODS

The following search terms were employed in PubMed, Web of Science, Embase, CNKI, Wanfang, VIP, SinoMed, and other scientific databases to retrieve pertinent literature on "cervical cancer," "apoptosis," "signaling pathway," "traditional Chinese medicine," "herbal monomers," "herbal components," "herbal extracts," and "herbal formulas."

RESULTS

It has been demonstrated that herbal medicines can induce apoptosis in cells of the cervix, a type of cancer, by influencing the signaling pathways involved.

CONCLUSION

A comprehensive literature search was conducted, and 148 papers from the period between January 2017 and December 2023 were identified as eligible for inclusion. After a meticulous process of screening, elimination and summary, generalization, and analysis, it was found that TCM can regulate multiple intracellular signaling pathways and related molecular targets, such as STAT3, PI3K/AKT, Wnt/β-catenin, MAPK, NF-κB, p53, HIF-1α, Fas/FasL and so forth. This regulatory capacity was observed to induce apoptosis in cervical cancer cells. The study of the mechanism of TCM against cervical cancer and the screening of new drug targets is of great significance for future research in this field. The results of this study will provide ideas and references for the future development of Chinese medicine in the diagnosis and treatment of cervical cancer.

T cell-related circRNA pairs to predict prognosis of patients with esophageal squamous cell carcinoma

The prognosis for esophageal squamous cell carcinoma (ESCC), a prevalent and aggressive form of cancer, remains poor despite advancements in treatment options. Addressing the gap in comprehensive prognostic information derived from circRNA expression profiles for ESCC, our study aimed to establish a linkage between circRNA expressions and ESCC prognosis. To achieve this, we first developed an optimized prognostic model named T cell-related risk score (TRRS), which integrates T cell-associated features with machine learning algorithms. In parallel, we re-analyzed existing RNA-seq datasets to redefine the expression profiles of circRNAs and mRNAs. Utilizing the TRRS as a foundational "bridge," we identified circRNAs correlated with TRRS, leading to the development of a novel circRNA pair-based prognostic model, the TCRS, which is independent of specific expression levels. Further investigations uncovered two circRNAs, circNLK(5,6,7).1 and circRC3H1(2).1, with potential functional significance. These findings underscore the utility of these risk scores as tools for predicting overall survival and identifying potential therapeutic targets for ESCC patients.

CircRNA and lncRNA-encoded peptide in diseases, an update review

Non-coding RNAs (ncRNAs), including circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), are unique RNA molecules widely identified in the eukaryotic genome. Their dysregulation has been discovered and played key roles in the pathogenesis of numerous diseases, including various cancers. Previously considered devoid of protein-coding ability, recent research has revealed that a small number of open reading frames (ORFs) within these ncRNAs endow them with the potential for protein coding. These ncRNAs-derived peptides or proteins have been proven to regulate various physiological and pathological processes through diverse mechanisms. Their emerging roles in disease diagnosis and targeted therapy underscore their potential utility in clinical settings. This comprehensive review aims to provide a systematic overview of proteins or peptides encoded by lncRNAs and circRNAs, elucidate their production and functional mechanisms, and explore their promising applications in cancer diagnosis, disease prediction, and targeted therapy.

CD58 defines regulatory macrophages within the tumor microenvironment

CD58 has been implicated in immune suppression and is associated with stemness in various types of cancer. Nonetheless, efficient biomarkers for assessing cancer patient response to immunotherapy are lacking. The present work focused on assessing the immune predictive significance of CD58 for patients with glioma. The expression of CD58 correlates with the clinicopathologic characteristics of patients with glioma, suggesting CD58high cells to signify glioma with tumorigenic potential. The CD58high cells displayed accelerated tumor formation compared to CD58low cells in vivo. Taken together, CD58 could potentially serve as a marker for glioma. CD58high glioma induces macrophage polarization through CXCL5 secretion, where M2 macrophages regulate PD-L1 expression within CD58high glioma via IL-6 production in vitro. Moreover, it was found that combination treatment with CD58 significantly increased the volume of tumors in the xenograft specimens. Evaluating CD58 expression represents a promising approach for identifying patients who can benefit from immunotherapy.

CD105+CAF-derived exosomes CircAMPK1 promotes pancreatic cancer progression by activating autophagy

Previous studies have shown that the heterogeneity of tumor-associated fibroblasts (CAFs) in the tumor microenvironment may play a critical role in tumorigenesis; however, the biological function of CAFs in pancreatic cancer is still controversial. In this study, we found that CD105-positive (CD105+) CAF-derived exosomes significantly promoted the proliferative and invasive metastatic abilities of pancreatic cancer cells. Furthermore, RNA-seq and qRT‒PCR experiments revealed circAMPK1 as a key molecule in exosomes from CD105+ CAFs that mediates the malignant progression of pancreatic cancer. Furthermore, we demonstrated that circAMPK1 encodes a novel protein (AMPK1-360aa) in pancreatic cancer cells. This protein competes with AMPK1 to bind to the ubiquitination ligase NEDD4, which inhibits AMPK1 protein degradation and ubiquitination and thereby increases AMPK1 levels. Finally, we demonstrated that AMPK1-360aa induces cellular autophagy via NEDD4/AMPK1 to promote the proliferation and invasion of pancreatic cancer cells. In summary, circAMPK1 in CD105+ CAF-derived exosomes may mediate pancreatic cancer cell proliferation and invasive metastasis by inducing autophagy in target cells. Moreover, circAMPK1 may competitively bind to ubiquitinating enzymes through the encoded protein AMPK1-360aa, which in turn inhibits the ubiquitination-mediated degradation of AMPK1 and contributes to the upregulation of AMPK1 expression, thus inducing cellular autophagy to mediate the malignant progression of pancreatic cancer.

A novel peptide encoded by circ-SLC9A6 promotes lipid dyshomeostasis through the regulation of H4K16ac-mediated CD36 transcription in NAFLD

BACKGROUND

As the leading cause of end-stage liver disease, nonalcoholic fatty liver disease (NAFLD) is mainly induced by lipid dyshomeostasis. The translation of endogenous circular RNAs (circRNAs) is closely related to the progression of various diseases, but the involvement of circRNAs in NAFLD has not been determined.

METHODS

Combined high-throughput circRNA profiles were used to identify circRNAs with translational potential. The underlying molecular mechanisms were investigated by RNA sequencing, pull-down/MS and site-specific mutagenesis.

RESULTS

In this study, we focused on circ-SLC9A6, an abnormally highly expressed circRNA in human and mouse liver tissue during NAFLD development that exacerbates metabolic dyshomeostasis in hepatocytes by encoding a novel peptide called SLC9A6-126aa in vivo and in vitro. YTHDF2-mediated degradation of m6A-modified circ-SLC9A6 was found to be essential for the regulation of SLC9A6-126aa expression. We further found that the phosphorylation of SLC9A6-126aa by AKT was crucial for its cytoplasmic localization and the maintenance of physiological homeostasis, whereas high-fat stress induced substantial translocation of unphosphorylated SLC9A6-126aa to the nucleus, resulting in a vicious cycle of lipid metabolic dysfunction. Nuclear SLC9A6-126aa promotes transcriptional activation of the target gene CD36 and enhances its occupancy of the CD36 promoter locus by regulating MOF-mediated histone H4K16 acetylation. Hepatic CD36 depletion significantly ameliorated hyperactivated MAPK signalling and lipid disturbance in SLC9A6-126aa transgenic mice. Clinically, increasing levels of SLC9A6-126aa were observed during NAFLD progression and were found to be positively correlated with the CD36 and MAPK cascades.

CONCLUSION

This study revealed the role of circ-SLC9A6-derived SLC9A6-126aa in the epigenetic modification-mediated regulation of lipid metabolism. Our findings may provide promising therapeutic targets for NAFLD and new insights into the pathological mechanisms of metabolic diseases.

HIGHLIGHTS

Under normal circumstances, driven by m6A modification, YTHDF2 directly recognizes and degrades circ-SLC9A6, thereby inhibiting the translation of SLC9A6-126aa. Additionally, AKT1 phosphorylates and inhibits the nuclear translocation of SLC9A6-126aa. In NAFLD, lipid overload leads to YTHDF2 and AKT1 deficiency, ultimately increasing the expression and nuclear import of SLC9A6-126aa. Nuclear SLC9A6-126aa binds directly to the CD36 promoter and initiates CD36 transcription, which induces lipid dyshomeostasis.

Targeting cytokine and chemokine signaling pathways for cancer therapy

Cytokines are critical in regulating immune responses and cellular behavior, playing dual roles in both normal physiology and the pathology of diseases such as cancer. These molecules, including interleukins, interferons, tumor necrosis factors, chemokines, and growth factors like TGF-β, VEGF, and EGF, can promote or inhibit tumor growth, influence the tumor microenvironment, and impact the efficacy of cancer treatments. Recent advances in targeting these pathways have shown promising therapeutic potential, offering new strategies to modulate the immune system, inhibit tumor progression, and overcome resistance to conventional therapies. In this review, we summarized the current understanding and therapeutic implications of targeting cytokine and chemokine signaling pathways in cancer. By exploring the roles of these molecules in tumor biology and the immune response, we highlighted the development of novel therapeutic agents aimed at modulating these pathways to combat cancer. The review elaborated on the dual nature of cytokines as both promoters and suppressors of tumorigenesis, depending on the context, and discussed the challenges and opportunities this presents for therapeutic intervention. We also examined the latest advancements in targeted therapies, including monoclonal antibodies, bispecific antibodies, receptor inhibitors, fusion proteins, engineered cytokine variants, and their impact on tumor growth, metastasis, and the tumor microenvironment. Additionally, we evaluated the potential of combining these targeted therapies with other treatment modalities to overcome resistance and improve patient outcomes. Besides, we also focused on the ongoing research and clinical trials that are pivotal in advancing our understanding and application of cytokine- and chemokine-targeted therapies for cancer patients.

A hidden proteome encoded by circRNAs in human placentas: Implications for uncovering preeclampsia pathogenesis

BACKGROUND

CircRNA-encoded proteins (CEPs) are emerging as new players in health and disease, and function as baits for the common partners of their cognate linear-spliced RNA encoded proteins (LEPs). However, their prevalence across human tissues and biological roles remain largely unexplored. The placenta is an ideal model for identifying CEPs due to its considerable protein diversity that is required to sustain fetal development during pregnancy. The aim of this study was to evaluate circRNA translation in the human placenta, and the potential roles of the CEPs in placental development and dysfunction.

METHODS

Multiomics approaches, including RNA sequencing, ribosome profiling, and LC-MS/MS analysis, were utilised to identify novel translational events of circRNAs in human placentas. Bioinformatics methods and the protein bait hypothesis were employed to evaluate the roles of these newly discovered CEPs in placentation and associated disorders. The pathogenic role of a recently identified CEP circPRKCB119aa in preeclampsia was investigated through qRT-PCR, Western blotting, immunofluorescence imaging and phenotypic analyses.

RESULTS

We found that 528 placental circRNAs bound to ribosomes with active translational elongation, and 139 were translated to proteins. The CEPs showed considerable structural homology with their cognate LEPs, but are more stable, hydrophobic and have a lower molecular-weight than the latter, all of which are conducive to their function as baits. On this basis, CEPs are deduced to be closely involved in placental function. Furthermore, we focused on a novel CEP circPRKCB119aa, and illuminated its pathogenic role in preeclampsia; it enhanced trophoblast autophagy by acting as a bait to inhibit phosphorylation of the cognate linear isoform PKCβ.

CONCLUSIONS

We discovered a hidden circRNA-encoded proteome in the human placenta, which offers new insights into the mechanisms underlying placental development, as well as placental disorders such as preeclampsia. Key points A hidden circRNA-encoded proteome in the human placenta was extensively identified and systematically characterised. The circRNA-encoded proteins (CEPs) are potentially related to placental development and associated disorders. A novel conserved CEP circPRKCB119aa enhanced trophoblast autophagy by inhibiting phosphorylation of its cognate linear-spliced isoform protein kinase C (PKC) β in preeclampsia.

The double-edged effects of IL-6 in liver regeneration, aging, inflammation, and diseases

Interleukin-6 (IL-6) is a pleiotropic cytokine and exerts its complex biological functions mainly through three different signal modes, called cis-, trans-, and cluster signaling. When IL-6 binds to its membrane or soluble receptors, the co-receptor gp130 is activated to initiate downstream signaling and induce the expression of target genes. In the liver, IL-6 can perform its anti-inflammatory activities to promote hepatocyte reprogramming and liver regeneration. On the contrary, IL-6 also exerts the pro-inflammatory functions to induce liver aging, fibrosis, steatosis, and carcinogenesis. However, understanding the roles and underlying mechanisms of IL-6 in liver physiological and pathological processes is still an ongoing process. So far, therapeutic agents against IL‑6, IL‑6 receptor (IL‑6R), IL-6-sIL-6R complex, or IL-6 downstream signal transducers have been developed, and determined to be effective in the intervention of inflammatory diseases and cancers. In this review, we summarized and highlighted the understanding of the double-edged effects of IL-6 in liver homeostasis, aging, inflammation, and chronic diseases, for better shifting the "negative" functions of IL-6 to the "beneficial" actions, and further discussed the potential therapeutic effects of targeting IL-6 signaling in the clinics.

Beyond traditional translation: ncRNA derived peptides as modulators of tumor behaviors

Within the intricate tapestry of molecular research, noncoding RNAs (ncRNAs) were historically overshadowed by a pervasive presumption of their inability to encode proteins or peptides. However, groundbreaking revelations have challenged this notion, unveiling select ncRNAs that surprisingly encode peptides specifically those nearing a succinct 100 amino acids. At the forefront of this epiphany stand lncRNAs and circRNAs, distinctively characterized by their embedded small open reading frames (sORFs). Increasing evidence has revealed different functions and mechanisms of peptides/proteins encoded by ncRNAs in cancer, including promotion or inhibition of cancer cell proliferation, cellular metabolism (glucose metabolism and lipid metabolism), and promotion or concerted metastasis of cancer cells. The discoveries not only accentuate the depth of ncRNA functionality but also open novel avenues for oncological research and therapeutic innovations. The main difficulties in the study of these ncRNA-derived peptides hinge crucially on precise peptide detection and sORFs identification. Here, we illuminate cutting-edge methodologies, essential instrumentation, and dedicated databases tailored for unearthing sORFs and peptides. In addition, we also conclude the potential of clinical applications in cancer therapy.

Tumor-associated macrophage-induced circMRCKα encodes a peptide to promote glycolysis and progression in hepatocellular carcinoma

The tumor-associated macrophages (TAMs) play multifaceted roles in the progression of hepatocellular carcinoma (HCC). However, the involvement of circular RNAs in the interplay between TAMs and HCC remains unclear. Based on Transwell co-culturing and circular RNA sequencing, this study revealed that TAMs enhanced tumor glycolysis and progression by upregulating circMRCKα in HCC cells. Patients with HCC who exhibited elevated circMRCKα levels presented significantly reduced overall survival and greater cumulative recurrence. Notably, we identified a novel functional peptide of 227 amino acids named circMRCKα-227aa, encoded by circMRCKα. Mechanistically, circMRCKα-227aa bound to USP22 and enhanced its protein level to obstruct HIF-1α degradation via the ubiquitin-proteasome pathway, thereby augmenting HCC glycolysis and progression. In clinical HCC samples, a positive correlation was observed between the expression of circMRCKα and the number of infiltrating CD68+ TAMs and expression of USP22. Furthermore, circMRCKα emerged as an independent prognostic risk factor both individually and in conjunction with CD68+ TAMs and USP22. This study illustrated that circMRCKα-227aa, a novel TAM-induced peptide, promotes tumor glycolysis and progression via USP22 binding and HIF-1α upregulation, suggesting that circMRCKα and TAMs could be combined as therapeutic targets in HCC.

The Diagnostic and Prognostic Potentials of Non-Coding RNA in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare biliary tract tumor with high malignancy. CCA is the second most common primary hepatobiliary cancer after hepatocarcinoma. Despite its rarity, the incidence of CCA is steadily increasing globally. Most patients with CCA are asymptomatic in the early stages, resulting in a late-stage diagnosis and poor prognosis. Finding reliable biomarkers is essential to improve CCA's early diagnosis and survival rate. Non-coding RNAs (ncRNAs) are non-protein coding RNAs produced by genomic transcription. This includes microRNAs, long non-coding RNAs, and circular RNAs. ncRNAs have multiple functions in regulating gene expression and are crucial for maintaining normal cell function and developing diseases. Many studies have shown that aberrantly expressed ncRNAs can regulate the occurrence and development of CCA. ncRNAs can be easily extracted and detected through tumor tissue and liquid biopsies, representing a potential tool for diagnosing and prognosis CCA. This review will provide a detailed update on the diagnostic and prognostic potentials of lncRNAs and cirRNAs as biomarkers in CCA.

Biological functions of circRNA in regulating the hallmarks of gastrointestinal cancer (Review)

Circular RNA (circRNA) was first observed in the cytoplasm of eukaryotic cells in 1979, but it was not characterized in detail until 2012, when high‑throughput sequencing technology was more advanced and available. Consequently, the mechanism of circRNA formation and its biological function have been progressively elucidated by researchers. circRNA is abundant in eukaryotic cells and exhibits a certain degree of organization, timing and disease‑specificity. Additionally, it is poorly degradable, meeting the characteristics of an ideal clinical biomarker. In the present review, the recent research progress of circRNAs in digestive tract malignant tumors was primarily discussed. This included the roles, biological functions and clinical significance of circRNA, providing references for its research value and clinical potential in gastrointestinal cancer.

Mesenchymal stem cells-derived IL-6 promotes invasion and metastasis of oral squamous cell carcinoma via JAK-STAT3 signalling

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is often diagnosed with cervical lymph node metastasis. Mesenchymal stem cells (MSCs) and interleukin-6 (IL-6) signalling are considered to play important roles in promoting tumour malignancy. The detailed biological interaction of MSCs and IL-6 and the subsequent effect on OSCC metastasis remain largely unclear. This study aimed to determine the effects and molecular mechanism of MSCs-derived IL-6 on tumour invasion and metastasis.

SUBJECTS AND METHODS

The effects of MSC-derived IL-6 and tocilizumab on the proliferation, mobility, and epithelial-mesenchymal transition (EMT) of OSCC cells and potential pathways were detected in vitro. In addition, a murine xenograft model was generated to verify the biological mechanism in vivo.

RESULTS

The results showed that the expression of MSCs and EMT-related signals was increased in poorly differentiated OSCC tissues. MSCs released a higher level of IL-6 and promoted the proliferation, invasion, and metastasis of OSCC cells and solid neoplasms, which were activated by the downstream molecules JAK and STAT3.

CONCLUSIONS

The results indicated that MSCs-derived IL-6-promoted tumour invasion and metastasis via JAK-STAT3 signalling. Blockade of this pathway by tocilizumab may be a potential treatment to improve the prognosis and survival rate of patients with OSCC.

N6-methyladenosine-modified circSLCO1B3 promotes intrahepatic cholangiocarcinoma progression via regulating HOXC8 and PD-L1

BACKGROUND

Refractoriness to surgical resection and chemotherapy makes intrahepatic cholangiocarcinoma (ICC) a fatal cancer of the digestive system with high mortality and poor prognosis. Important function invests circRNAs with tremendous potential in biomarkers and therapeutic targets. Nevertheless, it is still unknown how circRNAs contribute to the evolution of ICC.

METHODS

CircRNAs in paired ICC and adjacent tissues were screened by circRNAs sequencing. To explore the impact of circRNAs on ICC development, experiments involving gain and loss of function were conducted. Various experimental techniques, including quantitative real-time PCR (qPCR), western blotting, RNA immunoprecipitation (RIP), luciferase reporter assays, RNA pull-down, chromatin immunoprecipitation (ChIP), ubiquitination assays and so on were employed to identify the molecular regulatory role of circRNAs.

RESULTS

Herein, we reported a new circRNA, which originates from exon 9 to exon 15 of the SLCO1B3 gene (named circSLCO1B3), orchestrated ICC progression by promoting tumor proliferation, metastasis and immune evasion. We found that the circSLCO1B3 gene was highly overexpressed in ICC tissues and related to lymphatic metastasis, tumor sizes, and tumor differentiation. Mechanically, circSLCO1B3 not only promoted ICC proliferation and metastasis via miR-502-5p/HOXC8/SMAD3 axis, but also eradicated anti-tumor immunity via suppressing ubiquitin-proteasome-dependent degradation of PD-L1 by E3 ubiquitin ligase SPOP. We further found that methyltransferase like 3 (METTL3) mediated the m6A methylation of circSLCO1B3 and stabilizes its expression. Our findings indicate that circSLCO1B3 is a potential prognostic marker and therapeutic target in ICC patients.

CONCLUSIONS

Taken together, m6A-modified circSLCO1B3 was correlated with poor prognosis in ICC and promoted ICC progression not only by enhancing proliferation and metastasis via potentiating HOXC8 expression, but also by inducing immune evasion via antagonizing PD-L1 degradation. These results suggest that circSLCO1B3 is a potential prognostic marker and therapeutic target for ICC.

circUBE3C modulates myoblast development by binding to miR-191 and upregulating the expression of p27

Noncoding RNAs, including miRNAs (microRNAs) and circRNAs (circular RNA), are crucial regulators of myoblast proliferation and differentiation during muscle development. However, the specific roles and molecular mechanisms of circRNAs in muscle development remain poorly understood. Based on the existing circRNA-miRNA-mRNA network, our study focuses on circUBE3C, exploring its differential expression in fetal and adult muscle tissue of the cattle and investigating its impact on myoblast proliferation, apoptosis, and differentiation. The functional analysis of overexpression plasmids and siRNAs (small interfering RNAs) targeting circUBE3C was comprehensively evaluated by employing an array of advanced assays, encompassing CCK-8 (cell counting kit-8), EdU (5-ethynyl-20-deoxyuridine), flow cytometry, western blot analysis, and RT-qPCR. In vivo investigations indicated that overexpression of circUBE3C impedes the process of skeletal muscle regeneration. Mechanistically, we demonstrated that circUBE3C interacts with miR-191 and alleviates the suppression of p27 through cytoplasmic separation, bioinformatics prediction, dual-luciferase reporter assay, and RIP (RNA immunoprecipitation). Our findings indicate that the novel circRNA circUBE3C competitively binds to miR-191, thereby inhibiting proliferation and promoting apoptosis in bovine primary myoblasts and unveiling a regulatory pathway in bovine skeletal muscle development. These findings expand our understanding of circRNA functions in mammals and provide a basis for further exploration of their role in myogenesis and muscle diseases.

Circular RNAs in Breast Cancer: An Update

Breast cancer (BC), characterized by high heterogeneity, is the most commonly reported malignancy among females across the globe. Every year, many BC patients die owing to delayed diagnosis and treatment. Increasing researches have indicated that aberrantly expressed circular RNAs (circRNAs) are implicated in the tumorigenesis and progression of various tumors, including BC. Hence, this article provides a summary of the biogenesis and functions of circRNAs, as well as an examination of how circRNAs regulate the progression of BC. Moreover, circRNAs have aroused incremental attention as potential diagnostic and prognostic biomarkers for BC. Exosomes enriched with circRNAs can be secreted into the tumor microenvironment to mediate intercellular communication, affecting the progression of BC. Detecting the expression levels of exosomal circRNAs may provide reference for BC diagnosis and prognosis prediction. Illuminating insights into the earlier diagnosis and better treatment regimens of BC will be potentially available following elucidation of deeper regulatory mechanisms of circRNAs in this malignancy.

circGlis3 promotes β-cell dysfunction by binding to heterogeneous nuclear ribonucleoprotein F and encoding Glis3-348aa protein

Circular RNAs (circRNAs) are crucial regulators of β-cell function and are involved in lipotoxicity-induced β-cell damage in type 2 diabetes mellitus (T2DM). We previously identified that circGlis3, a circRNA derived from exon 4 of the diabetes susceptibility gene Glis3, was upregulated in lipotoxic β cells. However, the functional role and molecular mechanism of circGlis3 in β cells remain largely unknown. Here, we revealed that the splicing factor CUGBP Elav-Like Family Member 1 (CELF1) facilitated the biogenesis of circGlis3. Moreover, we established a transgenic mouse model and confirmed that the overexpression of circGlis3 impaired β-cell function. Mechanistically, circGlis3 bound to heterogeneous nuclear ribonucleoprotein F (hnRNPF) and blocked its nuclear translocation, thereby reducing Sirt1 levels. Additionally, circGlis3 encoded a 348aa protein that interacted with GLIS3 and inhibited its transcriptional activity. Our data uncover a critical role of circGlis3 in β-cell dysfunction, suggesting that circGlis3 may be a potential therapeutic target for T2DM.

Spleen tyrosine kinase facilitates the progression of papillary thyroid cancer regulated by the hsa_circ_0006417/miR-377-3p axis

Papillary thyroid cancer (PTC) is a prevalent malignancy worldwide. Spleen tyrosine kinase (SYK) is a crucial enzyme that participates in various biological processes, including cancer progression. This study aims to uncover the biological function of SYK in PTC. SYK expression patterns in PTC were evaluated using quantitative real time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC), and western blot. Cell function assays were performed to assess the effects of SYK on PTC. Bioinformatics analysis was conducted to identify intriguing microRNA (miRNA) and circular RNA (circRNA). Dual-Luciferase Reporter or RNA immunoprecipitation assays were used to investigate the correlation among SYK, miR-377-3p, and hsa_circ_0006417. SYK was upregulated in PTC. Overexpression of SYK exhibited a positive correlation with tumor size, lymph node metastasis, and unfavorable disease-free survival. Functional assays revealed that SYK exerted tumorigenic effect on PTC cells through mTOR/4E-BP1 pathway. Mechanistically, hsa_circ_0006417 and miR-377-3p regulated SYK expression, offering modulating its tumor-promoting effects. Collectively, SYK acts as an oncogene in PTC through mTOR/4E-BP1 pathway, which is regulated by the hsa_circ_0006417/miR-377-3p axis, thereby providing a potential alternative for PTC treatment.

Hsa_circ_0050900 affects ferroptosis in intrahepatic cholangiocarcinoma cells by targeting hsa‑miR-605‑3p to regulate SLC3A2

Intrahepatic cholangiocarcinoma (ICC) is a highly lethal hepatobiliary tumor with high aggressiveness. The role of circular RNA (circRNA) in ICC remains to be explored. The present study aimed to investigate whether hsa_circ_0050900 affected ferroptosis in ICC cells by regulating hsa-microRNA (miR)-605-3p/solute carrier family 3 member 2 (SLC3A2). Human ICC cells were cultured and hsa_circ_0050900 expression was evaluated by reverse transcription-quantitative PCR. hsa_circ_0050900 was knocked down and ferroptosis inhibitor ferrostatin-1 was added to HuCCT-1 cells. Following knockdown or overexpression of hsa-miR-605-3p, Fe2+, reactive oxygen species (ROS), glutathione peroxidase 4 and SLC3A2 levels were assessed using iron and ROS assay kit or RT-qPCR and western blotting, respectively. Cell function experiments were performed to examine proliferation and migration abilities. Dual-luciferase reporter gene and argonaute2-RNA immunoprecipitation assay verified the relationship among hsa_circ_0050900, hsa-miR-605-3p, and SLC3A2. hsa_circ_0050900 was derived from actinin alpha 4 gene and was elevated in ICC cells. Among HuCCT-1, QBC-939, HCCC-9810, and RBE cell lines, the highest expression was in HuCCT-1 cells. Inhibition of hsa_circ_0050900 inhibited proliferation and migration by facilitating ICC cell ferroptosis. hsa-miR-605-3p expression was elevated after knocking down hsa_circ_0050900 and hsa-miR-605-3p was negatively regulated by hsa_circ_0050900. In addition, hsa-miR-605-3p targeted SLC3A2. Overexpression of hsa-miR-605-3p regulated SLC3A2 to promote ICC cell ferroptosis and inhibit proliferation and migration. Taken together, knockdown of hsa_circ_0050900 inhibited SLC3A2 expression via sponging hsa-miR-605-3p to promote ICC cell ferroptosis, and finally suppressed proliferation and migration. The present study suggested that hsa_circ_0050900 was a potential therapeutic target for ICC.

TGFβ-induced circLTBP2 predicts a poor prognosis in intrahepatic cholangiocarcinoma and mediates gemcitabine resistance by sponging miR-338-3p

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (iCCA) is a deadly cancer worldwide with an increasing incidence and limited therapeutic options. Therefore, there is an urgent need to open the field to new concepts for identifying clinically relevant therapeutic targets and biomarkers. Here, we explored the role and the clinical relevance of circular RNA (circRNA) circLTBP2 in iCCA.

METHODS

Transforming growth factor β (TGFβ)-regulated circRNAs were identified by dedicated microarrays in human HuCC-T1 iCCA cell line, and their clinical relevance was evaluated in independent cohorts of patients. Gain and loss of function of circLTBP2 combined with functional tests was performed in vitro and in vivo in mice. RNA pulldown, microRNA sequencing, and RNA immunoprecipitation were performed to explore the sponging activity of circLTBP2.

RESULTS

CircLTBP2 (has_circ_0032603) was identified as a novel TGFβ-induced circRNA in several cholangiocarcinoma cell lines. CircLTBP2 promotes tumour cell proliferation, migration, and resistance to gemcitabine-induced apoptosis in vitro and tumour growth in vivo. Mechanistically, circLTBP2 acts as a competitive RNA regulating notably the activity of the tumour suppressor microRNA miR-338-3p, leading to the overexpression of its pro-metastatic targets. The restoration of miR-338-3p levels in iCCA cells reversed the pro-tumourigenic effects driven by circLTBP2, including the resistance to gemcitabine-induced apoptosis. In addition, circLTBP2 expression predicted a reduced survival, as detected in not only tumour tissues but also serum extracellular vesicles isolated from patients with iCCA.

CONCLUSIONS

CircLTBP2 is a novel effector of the pro-tumourigenic arm of TGFβ and a clinically relevant biomarker easily detected from liquid biopsies in iCCA.

IMPACT AND IMPLICATIONS

Intrahepatic cholangiocarcinoma (iCCA) is an aggressive cancer with limited therapeutic options. Opening the field to new concepts is urgently needed to improve the survival of patients. Here, we evaluated the role and the clinical relevance of circular RNA. We report that TGFβ-induced circLTBP2 contributes to CCA carcinogenesis and may constitute a clinically relevant prognostic biomarker detected in liquid biopsies.

A novel protein encoded by circVPS13D attenuates antiviral innate immunity by targeting MAVS in teleost fish

IMPORTANCE

The expression of circVPS13D was upregulated with SCRV invasion, which proved that circVPS13D was involved in the regulation of the antiviral immune response. Our study revealed that the existence of circVPS13D promoted the replication of SCRV. Functionally, circVPS13D negatively regulates the antiviral responses of fish. Mechanistically, we confirmed that circVPS13D inhibited RLRs antiviral signaling pathway via the encoded protein VPS13D-170aa by targeting MAVS. Our study provided novel insights into the roles of protein-coding circRNAs and supported VPS13D-170aa as a negative regulator in the antiviral immune responses of teleost fish.

Norcantharidin potentiates sorafenib antitumor activity in hepatocellular carcinoma rat model through inhibiting IL-6/STAT3 pathway

In hepatocellular carcinoma (HCC), sorafenib (Sora) efficacy is limited by primary and/or acquired resistance. Emerging evidence shows that the inflammatory factor interleukin 6 (IL-6) plays a role in Sora resistance. Norcantharidin (NCTD), a derivative of cantharidine, was identified as a potent IL-6 inhibitor. Thus, in this study, we evaluated NCTD ability to improve the Sora efficacy in HCC and its underlying molecular mechanisms. Male Sprague Dawely rats were administered NCTD (0.1 mg/kg/day; orally) or Sora (10 mg/kg day; orally) or combination for 6 weeks after HCC induction using thioacetamide (200 mg/kg; ip; 2 times/wk) for 16 weeks. Our results showed that NCTD greatly enhanced Sora activity against HCC and potentiated Sora-induced oxidative stress. NCTD enhanced Sora-induced tumor immunity reactivation by decreasing both fibrinogen-like protein 1 level and increasing both tumor necrosis factor-α gene expression along with CD8+ T cells number. Also, NCTD augmented Sora attenuation activity against TAA-induced angiogenesis and metastasis by decreasing VEGFA, HIF-1α, serum lactate dehydrogenase enzyme, and vimentin levels. The combined use of NCTD/Sora suppressed drug resistance and stemness by downregulating ATP-binding cassette subfamily G member 2, neurogenic locus notch homolog protein, spalt-like transcription factor 4, and CD133. NCTD boosted Sora antiproliferative and apoptotic activities by decreasing Ccnd1 and BCL2 expressions along with increasing BAX and caspase-3 expressions. To our knowledge, this study represents the first study providing evidence for the potential novel therapeutic use of NCTD/Sora combination for HCC. Moreover, no previous studies have reported the effect of NCTD on FGL1.

Circ-RAPGEF5 promotes intrahepatic cholangiocarcinoma progression by stabilizing SAE1 to facilitate SUMOylation

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy with a poor prognosis. The underlying functions and mechanisms of circular RNA and SUMOylation in the development of ICC remain poorly understood.

METHODS

Circular RNA hsa_circ_0001681 (termed Circ-RAPGEF5 hereafter) was identified by circular RNA sequencing from 19 pairs of ICC and adjacent tissue samples. The biological function of Circ-RAPGEF5 in tumor proliferation and metastasis was examined by a series of in vitro assays. A preclinical model was used to validate the therapeutic effect of targeting Circ-RAPGEF5. RNA pull-down and dual-luciferase reporter assays were used to access the RNA interactions. Western blot and Co-IP assays were used to detect SUMOylation levels.

RESULTS

Circ-RAPGEF5, which is generated from exons 2 to 6 of the host gene RAPGEF5, was upregulated in ICC. In vitro and in vivo assays showed that Circ-RAPGEF5 promoted ICC tumor proliferation and metastasis, and inhibited apoptosis. Additionally, high Circ-RAPGEF5 expression was significantly correlated with a poor prognosis. Further investigation showed that SAE1, a potential target of Circ-RAPGEF5, was also associated with poor oncological outcomes. RNA pull-down and dual-luciferase reporter assays showed an interaction of miR-3185 with Circ-RAPGEF5 and SAE1. Co-IP and western blot assays showed that Circ-RAPGEF5 is capable of regulating SUMOylation.

CONCLUSION

Circ-RAPGEF5 promotes ICC tumor progression and SUMOylation by acting as a sponge for miR-3185 to stabilize SAE1. Targeting Circ-RAPGEF5 or SAE1 might be a novel diagnostic and therapeutic strategy in ICC.

Tumor-derived CircRNA_102191 promotes gastric cancer and facilitates M2 macrophage polarization

BACKGROUND

Gastric cancer is a common malignant tumor of the digestive tract and the fourth leading cause of death from cancer-related diseases. In recent years, many studies have found that circular RNAs play an important role in cancer. Tumor-associated macrophages (TAMs) are also critical for tumor progression.

OBJECTIVE

This study examined the role of circRNA_102191 in gastric cancer progression.

METHODS

The relative mRNA levels were determined by qRT-PCR. Western blotting and ELISA were used to detect the protein levels. In vitro proliferation was assessed using CCK8 and clonogenic assays. The migration and invasion of cell lines were assessed by transwell-based assays. The interactions between molecules were detected using a luciferase reporter assay. M0 macrophages were induced with PMA. M1 macrophages were induced with LPS and IFN-γ, and M2 macrophages were induced with IL-4.

RESULTS

The expression of circRNA_102191 was enhanced significantly in gastric cancer cell lines and clinical tumor tissues. CircRNA_102191 promotes gastric cancer cell progression by regulating miR-493-3p and its downstream target gene XPR1. CircRNA_102191 can enhance the EMT process of gastric cancer cells by promoting the M2 polarization of macrophages.

CONCLUSION

CircRNA_102191 promotes the biological function of gastric cancer cells by regulating the miR-493-3p/XPR1 axis and M2 macrophage polarization.

Noncoding RNAs as regulators of STAT3 pathway in gastrointestinal cancers: Roles in cancer progression and therapeutic response

Gastrointestinal (GI) tumors (cancers of the esophagus, gastric, liver, pancreas, colon, and rectum) contribute to a large number of deaths worldwide. STAT3 is an oncogenic transcription factor that promotes the transcription of genes associated with proliferation, antiapoptosis, survival, and metastasis. STAT3 is overactivated in many human malignancies including GI tumors which accelerates tumor progression, metastasis, and drug resistance. Research in recent years demonstrated that noncoding RNAs (ncRNAs) play a major role in the regulation of many signaling pathways including the STAT3 pathway. The major types of endogenous ncRNAs that are being extensively studied in oncology are microRNAs, long noncoding RNAs, and circular RNAs. These ncRNAs can either be tumor-promoters or tumor-suppressors and each one of them imparts their activity via different mechanisms. The STAT3 pathway is also tightly modulated by ncRNAs. In this article, we have elaborated on the tumor-promoting role of STAT3 signaling in GI tumors. Subsequently, we have comprehensively discussed the oncogenic as well as tumor suppressor functions and mechanism of action of ncRNAs that are known to modulate STAT3 signaling in GI cancers.

The present roles and future perspectives of Interleukin-6 in biliary tract cancer

Biliary tract cancer (BTC) is a highly malignant tumor that originates from bile duct epithelium and is categorized into intrahepatic cholangiocarcinoma (iCCA), perihilar cholangiocarcinoma (pCCA), distal cholangiocarcinoma (dCCA) and gallbladder cancer (GBC) according to the anatomic location. Inflammatory cytokines generated by chronic infection led to an inflammatory microenvironment which influences the carcinogenesis of BTC. Interleukin-6 (IL-6), a multifunctional cytokine secreted by kupffer cells, tumor-associated macrophages, cancer-associated fibroblasts (CAFs) and cancer cells, plays a central role in tumorigenesis, angiogenesis, proliferation, and metastasis in BTC. Besides, IL-6 serves as a clinical biomarker for diagnosis, prognosis, and monitoring for BTC. Moreover, preclinical evidence indicates that IL-6 antibodies could sensitize tumor immune checkpoint inhibitors (ICIs) by altering the number of infiltrating immune cells and regulating the expression of immune checkpoints in the tumor microenvironment (TME). Recently, IL-6 has been shown to induce programmed death ligand 1 (PD-L1) expression through the mTOR pathway in iCCA. However, the evidence is insufficient to conclude that IL-6 antibodies could boost the immune responses and potentially overcome the resistance to ICIs for BTC. Here, we systematically review the central role of IL-6 in BTC and summarize the potential mechanisms underlying the improved efficacy of treatments combining IL-6 antibodies with ICIs in tumors. Given this, a future direction is proposed for BTC to increase ICIs sensitivity by blocking IL-6 pathways.

Circular RNA in cholangiocarcinoma: A systematic review and bibliometric analysis

BACKGROUND

Cholangiocarcinoma (CCA) is a common primary liver malignancy with a poor prognosis. Many studies have demonstrated the involvement of circular RNAs (circRNAs) in tumorigenesis and progression.

METHODS

Four online databases (PubMed, Web of Science, Embase, and Scopus) were searched on May 04, 2023, for original papers regarding CCA and circRNAs. Bibliometric analysis of included studies was performed on R Studio and GraphPad Prism.

RESULTS

Thirty studies were included in the systematic review and bibliometric analysis. The systematic review showed that circRNAs were involved in CCA proliferation, invasion, metastasis, chemotherapy resistance, and other biological processes and were related to the prognosis of patients and many clinicopathological features. Exosomal circRNAs provide a new idea for the early diagnosis of CCA. The bibliometric analysis showed a significant upward trend in the number of studies on CCA and circRNAs. The 30 included papers had 201 authors and were published in 22 English journals. The first paper was published in 2018, and the second paper was the most cited (148 citations).

CONCLUSION

This systematic review and bibliometric analysis demonstrates that circRNAs in CCA have not been studied enough. CircRNAs play an important role in the occurrence and progression of CCA. They may become new targets for the diagnosis, treatment, and prognostic monitoring of CCA.

DeepCIP: A multimodal deep learning method for the prediction of internal ribosome entry sites of circRNAs

Circular RNAs (circRNAs) have been found to have the ability to encode proteins through internal ribosome entry sites (IRESs), which are essential RNA regulatory elements for cap-independent translation. Identification of IRES elements in circRNA is crucial for understanding its function. Previous studies have presented IRES predictors based on machine learning techniques, but they were mainly designed for linear RNA IRES. In this study, we proposed DeepCIP (Deep learning method for CircRNA IRES Prediction), a multimodal deep learning approach that employs both sequence and structural information for circRNA IRES prediction. Our results demonstrate the effectiveness of the sequence and structure models used by DeepCIP in feature extraction and suggest that integrating sequence and structural information efficiently improves the accuracy of prediction. The comparison studies indicate that DeepCIP outperforms other comparative methods on the test set and real circRNA IRES dataset. Furthermore, through the integration of an interpretable analysis mechanism, we elucidate the sequence patterns learned by our model, which align with the previous discovery of motifs that facilitate circRNA translation. Thus, DeepCIP has the potential to enhance the study of the coding potential of circRNAs and contribute to the design of circRNA-based drugs. DeepCIP as a standalone program is freely available at https://github.org/zjupgx/DeepCIP.

The DDUP protein encoded by the DNA damage-induced CTBP1-DT lncRNA confers cisplatin resistance in ovarian cancer

Sustained activation of DNA damage response (DDR) signaling has been demonstrated to play vital role in chemotherapy failure in cancer. However, the mechanism underlying DDR sustaining in cancer cells remains unclear. In the current study, we found that the expression of the DDUP microprotein, encoded by the CTBP1-DT lncRNA, drastically increased in cisplatin-resistant ovarian cancer cells and was inversely correlated to cisplatin-based therapy response. Using a patient-derived human cancer cell model, we observed that DNA damage-induced DDUP foci sustained the RAD18/RAD51C and RAD18/PCNA complexes at the sites of DNA damage, consequently resulting in cisplatin resistance through dual RAD51C-mediated homologous recombination (HR) and proliferating cell nuclear antigen (PCNA)-mediated post-replication repair (PRR) mechanisms. Notably, treatment with an ATR inhibitor disrupted the DDUP/RAD18 interaction and abolished the effect of DDUP on prolonged DNA damage signaling, which resulted in the hypersensitivity of ovarian cancer cells to cisplatin-based therapy in vivo. Altogether, our study provides insights into DDUP-mediated aberrant DDR signaling in cisplatin resistance and describes a potential novel therapeutic approach for the management of platinum-resistant ovarian cancer.

CircRNAs regulate the crosstalk between inflammation and tumorigenesis: The bilateral association and molecular mechanisms

Inflammation, a hallmark of cancer, has been associated with tumor progression, transition into malignant phenotype and efficacy of the chemotherapeutic agents in cancer. Chronic inflammation provides a favorable environment for tumorigenesis by inducing immunosuppression, whereas acute inflammation prompts tumor suppression by generating anti-tumor immune responses. Inflammatory factors derived from interstitial cells or tumor cells can stimulate cell proliferation and survival by modulating oncogenes and/or tumor suppressors. Recently, a new class of RNAs, i.e., circular RNAs (circRNAs), has been implicated in inflammatory diseases. Although there are reports on circRNAs imparting functions in inflammatory insults, whether these circularized transcripts hold the potential to regulate inflammation-induced cancer or tumor-related inflammation, and modulate the interactions between tumor microenvironment (TME) and the inflammatory stromal/immune cells, awaits further elucidation. Contextually, the current review describes the molecular association between inflammation and cancer, and spotlights the regulatory mechanisms by which circRNAs can moderate TME in response to inflammatory signals/triggers. We also present comprehensive information about the immune cell(s)-specific expression and functions of the circRNAs in TME, modulation of inflammatory signaling pathways to drive tumorigenesis, and their plausible roles in inflammasomes and tumor development. Moreover, the therapeutic potential of these circRNAs in harnessing inflammatory responses in cancer is also discussed.

Newly discovered mechanisms that mediate tumorigenesis and tumour progression: circRNA-encoded proteins

Proteins produced by cap-independent translation mediated by an internal ribosome entry site (IRES) in circular RNAs (circRNAs) play important roles in tumour progression. To date, numerous studies have been performed on circRNAs and the proteins they encode. In this review, we summarize the biogenesis of circRNAs and the mechanisms regulating circRNA-encoded proteins expression. We also describe relevant research methods and their applications to biological processes such as tumour cell proliferation, metastasis, epithelial-mesenchymal transition (EMT), apoptosis, autophagy and chemoresistance. This paper offers deeper insights into the roles that circRNA-encoded proteins play in tumours. It also provides a theoretical basis for the use of circRNA-encoded proteins as biomarkers of tumorigenesis and for the development of new targets for tumour therapy.