Hsa_circ_0007312 Promotes Third-Generation Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Resistance through Pyroptosis and Apoptosis via the MiR-764/MAPK1 Axis in Lung Adenocarcinoma Cells

Transcription factor MAFK binds to circRPPH to regulate SIRT gene-mediated cellular pyroptosis and lung adenocarcinoma progression

OBJECTIVE

Lung adenocarcinoma (LUAD) represents the most prevalent subtype of lung cancer (LC), accounting for 50% of all LC cases, with its occurrence continuing to rise. Multiple pyroptotic pathway mediators are implicated in LC initiation. The study delved into the mechanism of circRPPH1 in pyroptosis in LUAD.

METHODS

We first examined the relationship between circRPPH1 and the clinical features of LUAD patients by analyzing circRNA gene expression profiles from the GEO database and validating findings with clinical samples. Downstream pathways influenced by circRPPH1 were identified and assessed for their roles in LUAD cell growth and pyroptosis using gain-and-loss-of-function assays.

RESULTS

circRPPH1 was significantly upregulated in LUAD and associated with poor prognosis. It binds to the transcription factor MAFK, enhancing SIRT1 expression and activating the MAFK-Keap1 signaling pathway. Reducing circRPPH1 expression decreased SIRT1 levels, inhibited cell proliferation both in vivo and ex vivo, and increased markers of cellular pyroptosis. Additionally, overexpressing SIRT1 mitigated the effects of circRPPH1 silencing.

CONCLUSION

circRPPH1 promotes LUAD progression by binding to MAFK, enhancing SIRT1 expression, and inhibiting cellular pyroptosis.

Pyroptosis in lung cancer: The emerging role of non-coding RNAs

Lung cancer remains an intractable malignancy worldwide, prompting novel therapeutic modalities. Pyroptosis, a lethal form of programmed cell death featured by inflammation, has been involved in cancer progression and treatment response. Simultaneously, non-coding RNA has been shown to have important roles in coordinating pattern formation and oncogenic pathways, including long non-coding RNA (lncRNAs), microRNA (miRNAs), circular RNA (circRNAs), and small interfering RNA (siRNAs). Recent studies have revealed that ncRNAs can promote or inhibit pyroptosis by interacting with key molecular players such as NLRP3, GSDMD, and various transcription factors. This dual role of ncRNAs offers a unique therapeutic potential to manipulate pyroptosis pathways, providing opportunities for innovative cancer treatments. In this review, we integrate current research findings to propose novel strategies for leveraging ncRNA-mediated pyroptosis as a therapeutic intervention in lung cancer. We explore the potential of ncRNAs as biomarkers for predicting patient response to treatment and as targets for overcoming resistance to conventional therapies.

Targeting non-coding RNAs to overcome osimertinib resistance in EGFR-mutated non-small cell lung cancer

Osimertinib, a third-generation inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, exhibits remarkable efficacy in prolonging the survival of patients with non-small cell lung cancer (NSCLC) carrying EGFR mutations, surpassing the efficacy of first- and second-generation EGFR tyrosine kinases. Nevertheless, the emergence of osimertinib resistance is inevitable, necessitating an investigation into the underlying mechanisms. Increasing evidence has revealed that non-coding RNAs (ncRNAs), including microRNAs, long ncRNAs, and circular RNAs, play a significant role in the development and progression of lung cancer. These ncRNAs regulate essential signaling pathways, offering a novel avenue for understanding the fundamental mechanisms of osimertinib resistance. Recent studies have reported the significant impact of ncRNAs on osimertinib resistance, achieved through various mechanisms that modulate treatment sensitivity. We provide a concise overview of the functions and underlying mechanisms of extensively researched ncRNAs in the development of osimertinib resistance and emphasize their potential clinical application in EGFR-mutated NSCLC resistant to osimertinib. Finally, we discuss the obstacles that must be addressed to effectively translate ncRNA-based approaches into clinical practice.

Role of non-coding RNAs mediated pyroptosis on cancer therapy: a review

INTRODUCTION

Non-coding RNAs (ncRNAs), which are incapable of encoding proteins, are involved in the progression of numerous tumors by altering transcriptional and post-transcriptional processing. Recent studies have revealed prominent features of ncRNAs in pyroptosis, a type of non-apoptotic programmed cellular destruction linked to an inflammatory reaction. Drug resistance has arisen gradually as a result of anti-apoptotic proteins, therefore strategies based on pyroptotic cell death have attracted increasing attention. We have observed that ncRNAs may exert significant influence on cancer therapy, chemotherapy, radio- therapy, targeted therapy and immunotherapy, by regulating pyroptosis.

AREAS COVERED

Literatures were searched (December 2023) for studies on cancer therapy for ncRNAs-mediated pyroptotic cell death.

EXPERT OPINION

The most universal mechanical strategy for ncRNAs to regulate target genes is competitive endogenous RNAs (ceRNA). Besides, certain ncRNAs could directly interact with proteins and modulate downstream genes to induce pyroptosis, resulting in tumor growth or inhibition. In this review, we aim to display that ncRNAs, predominantly long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs), could function as potential biomarkers for diagnosis and prognosis and produce new insights into anti-cancer strategies modulated by pyroptosis for clinical applications.

Emerging roles of circular RNAs in regulating the hallmarks of thyroid cancer

Thyroid cancer is a prevalent endocrine malignancy with increasing incidence in recent years. Although most thyroid cancers grow slowly, they can become refractory, leading to a high mortality rate once they exhibit recurrence, metastasis, resistance to radioiodine therapy, or a lack of differentiation. However, the mechanisms underlying these malignant characteristics remain unclear. Circular RNAs, a type of closed-loop non-coding RNAs, play multiple roles in cancer. Several studies have demonstrated that circular RNAs significantly influence the development of thyroid cancers. In this review, we summarize the circular RNAs identified in thyroid cancers over the past decade according to the hallmarks of cancer. We found that eight of the 14 hallmarks of thyroid cancers are regulated by circular RNAs, whereas the other six have not been reported to be correlated with circular RNAs. This review is expected to help us better understand the roles of circular RNAs in thyroid cancers and accelerate research on the mechanisms and cure strategies for thyroid cancers.

Non-coding RNAs as potential therapeutic targets for receptor tyrosine kinase signaling in solid tumors: current status and future directions

This review article presents an in-depth analysis of the current state of research on receptor tyrosine kinase regulatory non-coding RNAs (RTK-RNAs) in solid tumors. RTK-RNAs belong to a class of non-coding RNAs (nc-RNAs) responsible for regulating the expression and activity of receptor tyrosine kinases (RTKs), which play a critical role in cancer development and progression. The article explores the molecular mechanisms through which RTK-RNAs modulate RTK signaling pathways and highlights recent advancements in the field. This include the identification of potential new RTK-RNAs and development of therapeutic strategies targeting RTK-RNAs. While the review discusses promising results from a variety of studies, encompassing in vitro, in vivo, and clinical investigations, it is important to acknowledge the challenges and limitations associated with targeting RTK-RNAs for therapeutic applications. Further studies involving various cancer cell lines, animal models, and ultimately, patients are necessary to validate the efficacy of targeting RTK-RNAs. The specificity of ncRNAs in targeting cellular pathways grants them tremendous potential, but careful consideration is required to minimize off-target effects, the article additionally discusses the potential clinical applications of RTK-RNAs as biomarkers for cancer diagnosis, prognosis, and treatment. In essence, by providing a comprehensive overview of the current understanding of RTK-RNAs in solid tumors, this review emphasizes their potential as therapeutic targets for cancer while acknowledging the associated challenges and limitations.

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.

miR-125b-5p-MAPK1-C/EBPα feedback loop regulates all-trans retinoic acid resistance in acute promyelocytic leukemia

BACKGROUND

Various studies have highlighted the significance of miR-125b-5p in tumour chemotherapy resistance; However, whether miR-125b-5p is associated with all-trans retinoic acid (ATRA) resistance in acute promyelocytic leukemia (APL) has not been reported.

METHODS

Drug-resistance-related factors in APL were predicted using the DRESIS database. The expression levels of miR-125b-5p in ATRA-sensitive and ATRA-resistant APL cells were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR). A nitrotetrazolium blue (NBT) reduction assay and flow cytometry (FCM) were used to detect the effect of miR-125b-5p on ATRA resistance in APL cells. An APL xenograft tumour mouse model was established to determine the effect of miR-125b-5p on ATRA resistance. A dual-luciferase gene reporter assay, qRT-PCR, and western blotting verified the regulation by miR-125b-5p of its target gene, MAPK1, and the MAPK1 downstream factor, C/EBPα. An NBT reduction assay and FCM were used to detect the effect of C/EBPα on ATRA resistance in APL cells. Western blotting and qRT-PCR were used to assess the regulation of miR-125b-5p and MAPK1 by C/EBPα.

RESULTS

miR-125b-5p expression levels were dramatically increased in ATRA-resistant APL cells. Both in vitro and in vivo experiments revealed that miR-125b-5p overexpression enhanced ATRA resistance in APL. miR-125b-5p promoted ATRA resistance by sponging MAPK1. C/EBPα was negatively regulated by miR-125b-5p, which in addition, regulated ATRA resistance in APL cells. C/EBPα also regulated the miR-125b-5p-MAPK1 axis.

CONCLUSION

The findings of this study indicate that the miR-125b-5p-MAPK1-C/EBPα feedback loop regulated ATRA resistance in APL. Thus, miR-125b-5p may be a promising target for treating ATRA resistance in APL.

Characterization of circRNAs in established osimertinib‑resistant non‑small cell lung cancer cell lines

Drug resistance is an urgent problem to be solved in the treatment of non‑small‑cell lung cancer (NSCLC). Osimertinib is a third‑generation EGFR‑tyrosine kinase inhibitor, which can improve the efficacy and quality of life of patients; however, the inevitable resistance after long‑term use of osimertinib often leads to treatment failure. Cell lines are key tools for basic and preclinical studies. At present, few osimertinib‑resistant cell lines (HCC827‑OR and H1975‑OR) have been established. In the present study, osimertinib‑resistant cell lines were established by gradually increasing the drug concentration. Half‑maximal inhibitory concentration (IC50), cell morphology, whole exon sequencing, Cell Counting Kit‑8 assay, EdU staining and flow cytometry were used to evaluate the osimertinib‑resistant cell lines. Western blot analysis was used to detect the expression levels of key proteins involved in osimertinib resistance. The circular RNA (circRNA) expression profile was identified by RNA sequencing (RNA‑seq) analysis of HCC827, HCC827‑OR, H1975 and H1975‑OR cells. Subsequently, the biological roles of differentially expressed circRNAs were explored in in vitro studies. Osimertinib‑resistant cell lines were successfully established via treatment with an increasing concentration of osimertinib. Osimertinib IC50 and proliferation of resistant cells were much higher than those of sensitive cells. Notably, phosphorylated (p)‑AKT and p‑ERK were markedly activated in resistant cells, and the inhibitory effect of osimertinib on p‑AKT and p‑ERK was weaker in resistant cells than that in parental cells. RNA‑seq analysis identified differentially expressed circRNAs in HCC827, HCC827‑OR, H1975 and H1975‑OR cells. The most dysregulated circRNAs (circPDLIM5 and circPPP4R1) were selected for further functional study. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the host genes of differentially expressed circRNAs were associated with 'endocytosis' and 'regulation of autophagy'. In conclusion, the present study established osimertinib‑resistant cell lines and revealed that circRNAs may serve as a promising biomarker in NSCLC osimertinib resistance.

Long non-coding RNAs in non-small cell lung cancer: implications for EGFR-TKI resistance

Non-small cell lung cancer (NSCLC) is one of the most common types of malignant tumors as well as the leading cause of cancer-related deaths in the world. The application of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) has dramatically improved the prognosis of NSCLC patients who harbor EGFR mutations. However, despite an excellent initial response, NSCLC inevitably becomes resistant to EGFR-TKIs, leading to irreversible disease progression. Hence, it is of great significance to shed light on the molecular mechanisms underlying the EGFR-TKI resistance in NSCLC. Long non-coding RNAs (lncRNAs) are critical gene modulators that are able to act as oncogenes or tumor suppressors that modulate tumorigenesis, invasion, and metastasis. Recently, extensive evidence demonstrates that lncRNAs also have a significant function in modulating EGFR-TKI resistance in NSCLC. In this review, we present a comprehensive summary of the lncRNAs involved in EGFR-TKI resistance in NSCLC and focus on their detailed mechanisms of action, including activation of alternative bypass signaling pathways, phenotypic transformation, intercellular communication in the tumor microenvironment, competing endogenous RNAs (ceRNAs) networks, and epigenetic modifications. In addition, we briefly discuss the limitations and the clinical implications of current lncRNAs research in this field.

Pyroptosis: A promising target for lung cancer therapy

Pyroptosis is a type of programed cell death that differs from apoptosis, ferroptosis, or necrosis. Numerous studies have reported that it plays a critical role in tumorigenesis and modification of the tumor microenvironment in multiple tumors. In this review, we briefly describe the canonical, non-canonical, and alternative mechanisms of pyroptotic cell death. We also summarize the potential roles of pyroptosis in oncogenesis, tumor development, and lung cancer treatment, including chemotherapy, radiotherapy, targeted therapy, and immunotherapy. Pyroptosis has double-edged effects on the modulation of the tumor environment and lung cancer treatment. Further exploration of pyroptosis-based drugs could provide novel therapeutic strategies for lung cancer.

Landscape of circular RNAs in different types of lung cancer and an emerging role in therapeutic resistance (Review)

Lung cancer is one of the most common malignant tumor types and the leading cause of cancer‑associated death worldwide. Different types of lung cancer exhibit differences in terms of pathophysiology and pathogenesis, and also treatment and prognosis. Accumulating evidence has indicated that circular RNAs (circRNAs) are abnormally expressed among different types of lung cancer and confer important biological functions in progression and prognosis. However, studies comparing different circRNAs in lung cancer subtypes are scarce. Furthermore, circRNAs have an important role in drug resistance and are related to clinicopathological features in lung cancer. Summaries of the association of circRNAs with drug resistance are also scarce in the literature. The present study outlined the biological functions of circRNAs and focused on discriminating differential circRNA patterns and mechanisms in three different types of lung cancer. The emerging roles of circRNAs in the resistance to chemotherapy, targeted therapy, radiotherapy and immunotherapy were also highlighted. Understanding these aspects of circRNAs sheds light on novel physiological and pathophysiological processes of lung cancer and suggests the application of circRNAs as biomarkers for diagnosis and prognosis, as well as therapeutic resistance.