circCORO1C promotes the proliferation and metastasis of hepatocellular carcinoma by enhancing the expression of PD-L1 through NF-κB pathway

Circular RNA Circ_0002762 promotes cell migration and invasion in cervical squamous cell carcinoma via activating RelA/nuclear factor kappa B (Nf-kB) signalling pathway

Cervical cancer is a leading cause of cancer-related deaths, with cervical squamous cell carcinoma (CSCC) accounting for a majority of cases. Circular RNAs (circRNAs) have been repeatedly suggested as crucial effectors in modulating the development of multiple malignancies. The expression of circ_0002762 was predicted to be high in CSCC tissues in GEO dataset, but the functional role and underlying regulatory mechanism of circ_0002762 in CSCC was unclear. By series of functional assays and mechanism assays, supported by bioinformatics analysis, reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis and western blot assays, we identified that circ_0002762 aberrantly up-regulated in CSCC, promoting CSCC cell migration and invasion. Mechanically, circ_0002762 was transcriptionally activated by Fork head box A1 (FOXA1). Moreover, the involvement of nuclear factor kappa B (NF-kB) signalling in circ_0002762 regulation mechanism in CSCC cells was ascertained. Additionally, circ_0002762, predominantly accumulated in cell cytoplasm, was proved to recruit Mov10 RISC complex RNA helicase (MOV10) to enhance RelA mRNA stability, thus affecting CSCC cell migration and invasion. In summary, FOXA1-mediated circ_0002762 up-regulation could enhance the migratory and invasive abilities of CSCC cells via the MOV10/RelA/NF-kB pathway.

Olaparib Combined with Anti-PD1 Enhances Immunotherapy of Gastric Cancer Via NF-κB/c-Myc/PD-L1 Signaling

BACKGROUND

PARP inhibitors, effective in BRCA-mutated cancers, show potential in gastric cancer (GC) where homologous recombination defects (e.g., BRCA1/2 mutations) are common. Olaparib, a PARP inhibitor, upregulates PD-L1, suggesting synergy with PD-1 inhibitors for enhanced GC therapy.

METHODS

Using CCK-8 screening of 867 drugs, olaparib demonstrated potent GC cell inhibition. Western blot and qRT-PCR assessed PD-L1, c-MYC, COX-2, and NF-κB pathway proteins (p65/p-p65). Functional assays (Transwell, wound healing, colony formation) evaluated olaparib's effects on GC cell proliferation, migration, and invasion. A GC mouse model tested olaparib combined with anti-PD1. TCGA and Kaplan-Meier analyzed PARP expression-prognosis correlations.

RESULTS

Olaparib suppressed GC cell proliferation, migration, and invasion in vitro. Western blot revealed upregulated c-MYC, COX-2, p65, p-p65, and PD-L1, confirmed by qRT-PCR for PD-L1. Low PARP expression correlated with better GC patient survival. In vivo, olaparib synergized with anti-PD1 to enhance tumor suppression.

CONCLUSION

Olaparib activates the NF-κB/c-MYC pathway to elevate PD-L1, supporting its combination with PD-1 inhibitors as a promising GC therapeutic strategy.

ESRP1-mediated biogenesis of circPTPN12 inhibits hepatocellular carcinoma progression by PDLIM2/ NF-κB pathway

BACKGROUND

Emerging evidence indicates the pivotal involvement of circular RNAs (circRNAs) in cancer initiation and progression. Understanding the functions and underlying mechanisms of circRNAs in tumor development holds promise for uncovering novel diagnostic indicators and therapeutic targets. In this study, our focus was to elucidate the function and regulatory mechanism of hsa-circ-0003764 in hepatocellular carcinoma (HCC).

METHODS

A newly discovered hsa-circ-0003764 (circPTPN12) was identified from the circbase database. QRT-PCR analysis was utilized to assess the expression levels of hsa-circ-0003764 in both HCC tissues and cells. We conducted in vitro and in vivo experiments to examine the impact of circPTPN12 on the proliferation and apoptosis of HCC cells. Additionally, RNA-sequencing, RNA immunoprecipitation, biotin-coupled probe pull-down assays, and FISH were employed to confirm and establish the relationship between hsa-circ-0003764, PDLIM2, OTUD6B, P65, and ESRP1.

RESULTS

In HCC, the downregulation of circPTPN12 was associated with an unfavorable prognosis. CircPTPN12 exhibited suppressive effects on the proliferation of HCC cells both in vitro and in vivo. Mechanistically, RNA sequencing assays unveiled the NF-κB signaling pathway as a targeted pathway of circPTPN12. Functionally, circPTPN12 was found to interact with the PDZ domain of PDLIM2, facilitating the ubiquitination of P65. Furthermore, circPTPN12 bolstered the assembly of the PDLIM2/OTUD6B complex by promoting the deubiquitination of PDLIM2. ESRP1 was identified to bind to pre-PTPN12, thereby fostering the generation of circPTPN12.

CONCLUSIONS

Collectively, our findings indicate the involvement of circPTPN12 in modulating PDLIM2 function, influencing HCC progression. The identified ESRP1/circPTPN12/PDLIM2/NF-κB axis shows promise as a novel therapeutic target in the context of HCC.

The role of circular RNAs in regulating resistance to cancer immunotherapy: mechanisms and implications

Cancer immunotherapy has rapidly transformed cancer treatment, yet resistance remains a significant hurdle, limiting its efficacy in many patients. Circular RNAs (circRNAs), a novel class of non-coding RNAs, have emerged as pivotal regulators of gene expression and cellular processes. Increasing evidence indicates their involvement in modulating resistance to cancer immunotherapy. Notably, certain circRNAs function as miRNA sponges or interact with proteins, influencing the expression of immune-related genes, including crucial immune checkpoint molecules. This, in turn, shapes the tumor microenvironment and significantly impacts the response to immunotherapy. In this comprehensive review, we explore the evolving role of circRNAs in orchestrating resistance to cancer immunotherapy, with a specific focus on their mechanisms in influencing immune checkpoint gene expression. Additionally, we underscore the potential of circRNAs as promising therapeutic targets to augment the effectiveness of cancer immunotherapy. Understanding the role of circRNAs in cancer immunotherapy resistance could contribute to the development of new therapeutic strategies to overcome resistance and improve patient outcomes.

A therapeutical insight into the correlation between circRNAs and signaling pathways involved in cancer pathogenesis

Pre-messenger RNA molecules are back-spliced to create circular RNAs, which are non-coding RNA molecules. After a thorough investigation, it was discovered that these circRNAs have critical biological roles. CircRNAs have a variety of biological functions, including their ability to operate as microRNA sponges, interact with proteins to alter their stabilities and activities, and provide templates for the translation of proteins. Evidence supports a link between the emergence of numerous diseases, including various cancer types, and dysregulated circRNA expression. It is commonly known that a significant contributing element to cancer development is the disruption of numerous molecular pathways essential for preserving cellular and tissue homeostasis. The dysregulation of multiple biological processes is one of the hallmarks of cancer, and the molecular pathways linked to these processes are thought to be promising targets for therapeutic intervention. The biological and carcinogenic effects of circRNAs in the context of cancer are thoroughly reviewed in this article. Specifically, we highlight circRNAs' involvement in signal transduction pathways and their possible use as novel biomarkers for the early identification and prognosis of human cancer.

Mechanisms of immune checkpoint inhibitors: insights into the regulation of circular RNAS involved in cancer hallmarks

Current treatment strategies for cancer, especially advanced cancer, are limited and unsatisfactory. One of the most substantial advances in cancer therapy, in the last decades, was the discovery of a new layer of immunotherapy approach, immune checkpoint inhibitors (ICIs), which can specifically activate immune cells by targeting immune checkpoints. Immune checkpoints are a type of immunosuppressive molecules expressed on immune cells, which can regulate the degree of immune activation and avoid autoimmune responses. ICIs, such as anti-PD-1/PD-L1 drugs, has shown inspiring efficacy and broad applicability across various cancers. Unfortunately, not all cancer patients benefit remarkably from ICIs, and the overall response rates to ICIs remain relatively low for most cancer types. Moreover, the primary and acquired resistance to ICIs pose serious challenges to the clinical application of cancer immunotherapy. Thus, a deeper understanding of the molecular biological properties and regulatory mechanisms of immune checkpoints is urgently needed to improve clinical options for current therapies. Recently, circular RNAs (circRNAs) have attracted increasing attention, not only due to their involvement in various aspects of cancer hallmarks, but also for their impact on immune checkpoints in shaping the tumor immune microenvironment. In this review, we systematically summarize the current status of immune checkpoints in cancer and the existing regulatory roles of circRNAs on immune checkpoints. Meanwhile, we also aim to settle the issue in an evidence-oriented manner that circRNAs involved in cancer hallmarks regulate the effects and resistance of ICIs by targeting immune checkpoints.

The current status and future of PD-L1 in liver cancer

The application of immunotherapy in tumor, especially immune checkpoint inhibitors (ICIs), has played an important role in the treatment of advanced unresectable liver cancer. However, the efficacy of ICIs varies greatly among different patients, which has aroused people's attention to the regulatory mechanism of programmed death ligand-1 (PD-L1) in the immune escape of liver cancer. PD-L1 is regulated by multiple levels and signaling pathways in hepatocellular carcinoma (HCC), including gene variation, epigenetic inheritance, transcriptional regulation, post-transcriptional regulation, and post-translational modification. More studies have also found that the high expression of PD-L1 may be the main factor affecting the immunotherapy of liver cancer. However, what is the difference of PD-L1 expressed by different types of cells in the microenvironment of HCC, and which type of cells expressed PD-L1 determines the effect of tumor immunotherapy remains unclear. Therefore, clarifying the regulatory mechanism of PD-L1 in liver cancer can provide more basis for liver cancer immunotherapy and combined immune treatment strategy. In addition to its well-known role in immune regulation, PD-L1 also plays a role in regulating cancer cell proliferation and promoting drug resistance of tumor cells, which will be reviewed in this paper. In addition, we also summarized the natural products and drugs that regulated the expression of PD-L1 in HCC.

Circ_0124208 Promotes the Progression of Hepatocellular Carcinoma by Regulating the miR-338-3p/LAMC1 Axis

Hundreds of circular RNAs (circRNAs) have been identified as key regulators in biological processes; however, only few of these circRNAs have been functionally described to participate in the development of hepatocellular carcinoma (HCC). The present study aimed to reveal the function and molecular mechanisms of circ_0124208 in HCC. Real-time quantitative PCR revealed the upregulation of circ_0124208 in HCC tissues and cells. Based on cell functional experiments, silencing circ_0124208 attenuated proliferation and migration, but boosted the apoptosis of Hep 3B and Huh7 cells in vitro. The in vivo experiment further validated the repression of tumor growth via circ_0124208 knockdown. RNA immunoprecipitation and dual-luciferase reporter assays showed that circ_0124208 sponged miR-338-3p and reduced its expression. miR-338-3p inhibition was found to partially reverse the tumor-suppressive effects caused by circ_0124208 in Hep 3B and Huh7 cells. Furthermore, miR-338-3p directly targeted laminin subunit gamma 1 (LAMC1). The malignancy of Hep 3B and Huh7 cell was decreased by LAMC1 knockdown, and this effect was mitigated by miR-338-3p suppression. Overall, circ_0124208 was demonstrated for the first time to play a crucial role as an oncogene in HCC, implying that it could be a useful biomarker for HCC diagnosis. Furthermore, the circ_0124208/miR-338-3p/LAMC1 axis can be used as a potential therapeutic target for HCC treatment.

Multifaceted role of NF-κB in hepatocellular carcinoma therapy: Molecular landscape, therapeutic compounds and nanomaterial approaches

The predominant kind of liver cancer is hepatocellular carcinoma (HCC) that its treatment have been troublesome difficulties for physicians due to aggressive behavior of tumor cells in proliferation and metastasis. Moreover, stemness of HCC cells can result in tumor recurrence and angiogenesis occurs. Another problem is development of resistance to chemotherapy and radiotherapy in HCC cells. Genomic mutations participate in malignant behavior of HCC and nuclear factor-kappaB (NF-κB) has been one of the oncogenic factors in different human cancers that after nuclear translocation, it binds to promoter of genes in regulating their expression. Overexpression of NF-κB has been well-documented in increasing proliferation and invasion of tumor cells and notably, when its expression enhances, it induces chemoresistance and radio-resistance. Highlighting function of NF-κB in HCC can shed some light on the pathways regulating progression of tumor cells. The first aspect is proliferation acceleration and apoptosis inhibition in HCC cells mediated by enhancement in expression level of NF-κB. Moreover, NF-κB is able to enhance invasion of HCC cells via upregulation of MMPs and EMT, and it triggers angiogenesis as another step for increasing spread of tumor cells in tissues and organs. When NF-κB expression enhances, it stimulates chemoresistance and radio-resistance in HCC cells and by increasing stemness and population of cancer-stem cells, it can provide the way for recurrence of tumor. Overexpression of NF-κB mediates therapy resistance in HCC cells and it can be regulated by non-coding RNAs in HCC. Moreover, inhibition of NF-κB by anti-cancer and epigenetic drugs suppresses HCC tumorigenesis. More importantly, nanoparticles are considered for suppressing NF-κB axis in cancer and their prospectives and results can also be utilized for treatment of HCC. Nanomaterials are promising factors in treatment of HCC and by delivery of genes and drugs, they suppress HCC progression. Furthermore, nanomaterials provide phototherapy in HCC ablation.

Circular RNAs in Parkinson's Disease: Reliable Biological Markers and Targets for Rehabilitation

In clinical practice, the underlying pathogenesis of Parkinson's disease (PD) remains unknown. Circular RNAs (circRNAs) have good biological properties and can be used as biological marker. Rehabilitation as a third treatment alongside drug and surgery has been shown to be clinically effective, but biomarkers of rehabilitation efficiency at genetic level is still lacking. In this study, we identified differentially expressed circRNAs in peripheral blood exosomes between PD patients and health controls (HCs) and determined whether these circRNAs changed after rehabilitation, to explore the competing RNA networks and epigenetic mechanisms affected. We found that there were 558 upregulated and 609 downregulated circRNAs in PD patients compared to HCs, 3398 upregulated and 479 downregulated circRNAs in PD patients after rehabilitation compared to them before rehabilitation, along with 3721 upregulated and 635 downregulated circRNAs in PD patients after rehabilitation compared to HCs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that differentially expressed circRNAs may affect the stability of the cellular actin backbone and synaptic structure by influencing the aggregation of α-synuclein (a-syn). We selected two circRNAs overexpressed in PD patients for validation (hsa_circ_0001535 and hsa_circ_0000437); the results revealed that their expression levels were all reduced to varying degrees (p < 0.05) after rehabilitation. After network analysis, we believe that hsa_circ_0001535 may be related to the aggregation of a-syn, while hsa_circ_0000437 may act on hsa-let-7b-5p or hsa-let-7c-5p through sponge effect to cause inflammatory response. Our findings suggest that rehabilitation can mitigate the pathological process of PD by epigenetic means.

The Interaction of Programmed Cell Death Protein and Its Ligands with Non-Coding RNAs in Neoplasms: Emerging Anticancer Immunotherapeutics

Recent studies have demonstrated that cancer cells can elude immune cells by creating a sanctuary within the tumor’s microenvironment. Large amounts of immune-suppressing signaling proteins can be expressed by cancer cells. One of the most important mechanisms in this system is immune suppression caused by tumors and the modulation of the immune checkpoint. The immune checkpoint is modulated by both the programmed cell death protein 1 (PD-1) and its ligands, programmed death ligand 1 (PD-L1) and PD-L2. Non-coding RNAs (ncRNA), including the more well-known microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), all play roles in the regulation of biological processes and extensive diseases such as cancer. Thus, the focus of this study is on the interactions between the programmed death protein and its ligands with miRNAs, lncRNAs, and circRNAs during tumorigenesis and tumor progression. Furthermore, some FDA-approved drugs for the treatment of various cancers were based on their interactions with PD-1, PD-Ls, and ncRNAs. This promising strategy is still in the production stages, with additional results and clinical trials being processed.

Circular RNAs in cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most common primary biliary malignancy with an adverse prognosis. Although its incidence is relatively low, early diagnosis is difficult due to the lack of specific symptoms. Current treatment options for CCA are limited, resulting in a low curative rate. Circular RNAs (circRNAs) have become a new research hotspot in recent years, and they are frequently dysregulated in CCA and may become therapeutic targets and prognostic biomarkers of CCA. Accumulating evidence has demonstrated that numerous dysregulated circRNAs are vital players in the etiopathogenesis of CCA. Aberrant expression of specific circRNAs was correlated with unfavourable clinical characteristics in CCA. Many studies have found that circRNAs are involved in the progression and development of CCA through various mechanisms, including competitive inhibition of miRNAs via the competing endogenous RNA (ceRNA) network, interaction with RNA-binding proteins (RBPs), activation of cancer-related signalling pathways, and regulation of proteins and peptides. Additionally, some circRNAs are involved in the inflammatory microenvironment of CCA and play a crucial role in chemotherapy drug resistance. Thus, they are essential for the early diagnosis and prediction of CCA, and more attention should be given to the roles and mechanisms of circRNAs in CCA. In this review, we summarize the abnormal expression of circRNAs in CCA and the specific inflammatory microenvironment involved, as well as the roles and mechanisms of circRNAs in the occurrence and development of CCA. We also review the latest knowle dge on circRNAs in CCA and discuss the challenges associated with the introduction of circRNAs into clinical practice and their potential clinical value.

The roles and mechanisms of circular RNAs related to mTOR in cancers

BACKGROUND

Circular RNAs (circRNAs) are stable molecules with covalently closed structures that have an irreplaceable role in the occurrence, progression, and even treatment of plenty of cancers. Mammalian/mechanistic target of rapamycin (mTOR) is a key regulator in cancers and plays several biological functions, such as proliferation, migration, invasion, autophagy, and apoptosis.

METHODS

All data were collected through PubMed and CNKI, using terms including "circRNA," "mTOR," "caner," "signaling pathway," "biomarker," "diagnosis," "treatment." Articles published in Chinese and English were included.

RESULTS

In this review, the expression, function, and mechanism of circRNA-associated mTOR in cancers were described. CircRNA-associated-mTOR can regulate the progression and therapy of a variety of cancers in multiple signaling pathways, such as phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mTOR, mitogen-activated protein kinase (MAPK)/mTOR, and AMP-activated protein kinase (AMPK)/mTOR axis. These cancers including esophageal carcinoma (circLPAR3, ciRS-7), gastric cancer (circNRIP1, hsa_circ_0010882, hsa_circ_0000117, hsa_circ_0072309, and circST3GAL6), colorectal cancer (hsa_circ_0000392, hsa_circ_0084927, hsa_circ_0104631, and circFBXW7), liver cancer (circC16orf62, hsa_circ_100338, hsa_circ_0004001, hsa_circ_0004123, hsa_circ_0075792, hsa_circ_0079299, and hsa_circ_0002130), pancreatic cancer (circ-IARS and circRHOBTB3), renal carcinoma (ciRS-7), bladder cancer (circUBE2K), prostate cancer (circMBOAT2 and circ-ITCH), ovarian cancer (circEEF2, circRAB11FIP1, circMYLK, and circTPCN), endometrial cancer (hsa_circ_0002577 and circWHSC1), lung cancer (circHIPK3, hsa_circ_0001666), thyroid cancer (hsa_circ_0007694 and hsa_circ_0008274), glioma (circGFRA1, circ-MAPK4, circPCMTD1, and hsa_circ_0037251), osteosarcoma (circTCF25), leukemia (circ-PRKDC), and breast cancer (hsa_circ_0000199, circUBAP2, and circWHSC1).

Circular RNAs Involved in the Regulation of the Age-Related Pathways

Circular RNAs (circRNAs) are a class of covalently circular noncoding RNAs that have been extensively studied in recent years. Aging is a process related to functional decline that is regulated by signal transduction. An increasing number of studies suggest that circRNAs can regulate aging and multiple age-related diseases through their involvement in age-related signaling pathways. CircRNAs perform several biological functions, such as acting as miRNA sponges, directly interacting with proteins, and regulating transcription and translation to proteins or peptides. Herein, we summarize research progress on the biological functions of circRNAs in seven main age-related signaling pathways, namely, the insulin-insulin-like, PI3K-AKT, mTOR, AMPK, FOXO, p53, and NF-κB signaling pathways. In these pathways, circRNAs mainly function as miRNA sponges. In this review, we suggest that circRNAs are widely involved in the regulation of the main age-related pathways and are potential biomarkers for aging and age-related diseases.

LINC00244 suppresses cell growth and metastasis in hepatocellular carcinoma by downregulating programmed cell death ligand 1

The role of programmed cell death ligand 1 (PD-L1) in suppressing antitumor immune responses has been widely reported, and recent studies showed that PD-L1 also plays an important role in epithelial-mesenchymal transition (EMT), determination of tumor cell phenotypes, metastasis, and drug resistance. Long non-coding RNAs (lncRNAs) are involved in a variety of epigenetic regulatory processes. The tumorigenesis and development of most cancers cannot be studied separately from their regulation by lncRNAs. To explore the epigenetic regulation of PD-L1, we identified an lncRNA, LINC00244, which reduced PD-L1 expression and predicted good clinical outcomes in hepatocellular carcinoma (HCC). LINC00244 inhibited the proliferation, invasion, and metastasis of HCC by downregulating PD-L1 expression. In addition, low LINC00244 expression activated epithelial-mesenchymal transition (EMT) pathways and facilitated the rapid growth and metastasis of HCC cells. Thus, LINC00244 is a potential therapeutic target for HCC.