Investigation and Characterization of the RAS/RAF/MEK/ERK Pathway and Other Signaling Pathways in Chronic Sinusitis with Nasal Polyps.

BACKGROUND: The clinical outcomes of drug treatments and surgical interventions for chronic sinusitis with nasal polyps (CRSwNPs) are suboptimal, and the high recurrence rate remains a significant challenge in clinical practice. Targeted therapies such as biologics provide new perspectives and directions for treating CRSwNP. SUMMARY: With the continuous investigation of signaling pathways, RAS/RAF/MEK/ERK signaling pathway and other signaling pathways including Hippo, JAK-STAT, Wnt, TGF-ß, PI3K, Notch, and NF-κB were confirmed to play an important role in the progression of CRSwNP. Among them, the abnormality of RAS/RAF/MEK/ERK signaling pathway is accompanied by the abnormality of this apoptotic component, which may provide new research directions for targeting the components of signaling pathways to mediate apoptosis. KEY MESSAGES: Abnormalities in signaling pathways are particularly important in studying the pathogenesis and treatment of CRSwNP. Therefore, this review summarizes the ongoing investigation and characterization of RAS/RAF/MEK/ERK signaling pathway and other signaling pathways in CRSwNP, which provides constructive ideas and directions for improving the treatment of CRSwNP.

SARS-CoV-2 NSP14 induces AP-1 transcriptional activity via its interaction with MEK.

The NSP14 protein of SARS-CoV-2 not only facilitates viral replication but also plays a pivotal role in activating the host immune system by enhancing cytokine production. In this study, we found that NSP14 markedly activated the activator protein 1 (AP-1) pathway by increasing the phosphorylation of ERK (p-ERK), which enters the nucleus and promotes AP-1 transcription. The screening of the main proteins of the ERK pathway revealed that NSP14 could interact with MEK, a kinase of ERK, and increase the level of phosphorylated MEK. The addition of the MEK inhibitor U0126 suppressed the level of p-ERK induced by NSP14 and partly blocked cytokine production, suggesting that NSP14 activates MEK to enhance AP-1 signaling. Further investigation demonstrated that the ExoN domain of NSP14 might be crucial for the interaction and activation of MEK. These results suggest a novel mechanism by which NSP14 of SARS-CoV-2 induces a proinflammatory response in the host.

CircRAPGEF5 acts as a modulator of RAS/RAF/MEK/ERK signaling during colorectal carcinogenesis.

Mutations in oncogenes such as KRAS, NRAS and BRAF promote the growth and survival of tumors, while excessive RAS/RAF/MEK/ERK activation inhibits tumor growth. In this study we examined the precise regulatory machinery that maintains a moderate RAS/RAF/MEK/ERK pathway activation during CRC. Here, using bioinformatic analysis, transcriptomic profiling, gene silencing and cellular assays we discovered that a circular RNA, circRAPGEF5, is significantly upregulated in KRAS mutant colorectal cancer (CRC) cells. CircRAPGEF5 suppressed mutant and constitutively activated KRAS and the expression of the death receptor TNFRSF10A. Silencing of circRAPGEF5-induced RAS/RAF/MEK/ERK signaling hyperactivation and apoptosis in CRC cells suggesting that an upregulation of circRAPEF5 may suppress the expression of TNFRSF10A and aid CRC progression by preventing apoptosis, while the direct interactions between circRAPGEF5 and elements of the RAS/RAF/MEK/ERK pathway was not identified, which nevertheless can be the basis for future research. Moreover, EIF4A3, was observed to share a similar expression pattern with circRAPEF5 and demonstrated to be a major controller of circRAPGEF5 via the promotion of circRAPGEF5 circularization and its silencing reduced circRAPGEF5 levels. Taken together, our findings reveal a mechanism of accurate RAS/RAF/MEK/ERK signaling regulation during CRC progression maintained by upregulation of circRAPGEF5 which may be a plausible target for future clinical applications that seek to induce CRC cell apoptosis via the RAS/RAF/MEK/ERK signaling pathway.

Trametinib boosts palbociclib's efficacy in breast cancer via autophagy inhibition.

Breast cancer, a predominant global health issue, requires ongoing exploration of new therapeutic strategies. Palbociclib (PAL), a well-known cyclin-dependent kinase (CDK) inhibitor, plays a critical role in breast cancer treatment. While its efficacy is recognized, the interplay between PAL and cellular autophagy, particularly in the context of the RAF/MEK/ERK signaling pathway, remains insufficiently explored. This study investigates PAL's inhibitory effects on breast cancer using both in vitro (MCF7 and MDA-MB-468 cells) and in vivo (tumor-bearing nude mice) models. Aimed at elucidating the impact of PAL on autophagic processes and exploring the potential of combining it with trametinib (TRA), an MEK inhibitor, our research seeks to address the challenge of PAL-induced drug resistance. Our findings reveal that PAL significantly decreases the viability of MCF7 and MDA-MB-468 cells and reduces tumor size in mice while showing minimal cytotoxicity in MCF10A cells. However, PAL also induces protective autophagy, potentially leading to drug resistance via the RAF/MEK/ERK pathway activation. Introducing TRA effectively neutralized this autophagy, enhancing PAL's anti-tumor efficacy. A combination of PAL and TRA synergistically reduced cell viability and proliferation, and in vivo studies showed notable tumor size reduction. In conclusion, the PAL and TRA combination emerges as a promising strategy for overcoming PAL-induced resistance, offering a new horizon in breast cancer treatment.

Targeting the RAS upstream and downstream signaling pathway for cancer treatment.

Cancer often involves the overactivation of RAS/RAF/MEK/ERK (MAPK) and PI3K-Akt-mTOR pathways due to mutations in genes like RAS, RAF, PTEN, and PIK3CA. Various strategies are employed to address the overactivation of these pathways, among which targeted therapy emerges as a promising approach. Directly targeting specific proteins, leads to encouraging results in cancer treatment. For instance, RTK inhibitors such as imatinib and afatinib selectively target these receptors, hindering ligand binding and reducing signaling initiation. These inhibitors have shown potent efficacy against Non-Small Cell Lung Cancer. Other inhibitors, like lonafarnib targeting Farnesyltransferase and GGTI 2418 targeting geranylgeranyl Transferase, disrupt post-translational modifications of proteins. Additionally, inhibition of proteins like SOS, SH2 domain, and Ras demonstrate promising anti-tumor activity both in vivo and in vitro. Targeting downstream components with RAF inhibitors such as vemurafenib, dabrafenib, and sorafenib, along with MEK inhibitors like trametinib and binimetinib, has shown promising outcomes in treating cancers with BRAF-V600E mutations, including myeloma, colorectal, and thyroid cancers. Furthermore, inhibitors of PI3K (e.g., apitolisib, copanlisib), AKT (e.g., ipatasertib, perifosine), and mTOR (e.g., sirolimus, temsirolimus) exhibit promising efficacy against various cancers such as Invasive Breast Cancer, Lymphoma, Neoplasms, and Hematological malignancies. This review offers an overview of small molecule inhibitors targeting specific proteins within the RAS upstream and downstream signaling pathways in cancer.

TCF19 promotes cell proliferation and tumor formation in lung cancer by activating the Raf/MEK/ERK signaling pathway.

OBJECTIVE: This study aimed to investigate TCF19's role in lung cancer development, specifically its involvement in the RAF/MEK/ERK signaling pathway. METHODS: Lung cancer tissue analysis revealed significant TCF19 overexpression. In vitro experiments using A549 and Hop62 cells with TCF19 overexpression demonstrated enhanced cell growth. Transgenic mouse models confirmed TCF19's role in primary tumor development. Transcriptome sequencing identified altered gene expression profiles, linking TCF19 to RAF/MEK/ERK pathway activation. Functional assays elucidated underlying mechanisms, revealing increased phosphorylation of Raf1, MEK1/2, and ERK1/2. Inhibiting RAF1 or ERK through shRaf1 or ERK inhibitor reduced cell cycle-related proteins and inhibited TCF19-overexpressing cell growth. RESULTS: TCF19 was identified as an oncogene in lung carcinoma, specifically impacting the RAF/MEK/ERK pathway. Elevated TCF19 levels in lung cancer suggest targeting TCF19 or its associated pathways as a promising strategy for disease management. CONCLUSION: This study unveils TCF19's oncogenic role in lung cancer, emphasizing its modulation of the RAF/MEK/ERK pathway and presenting a potential therapeutic target for TCF19-overexpressing lung cancers.

Huanglian Jiedu decoction alleviates neurobehavioral damage in mice with chronic alcohol exposure through the RAS-RAF-MEK-ERK pathway.

Objective: Long-term alcohol consumption can cause organic damage to the brain, resulting in mental and nervous system abnormalities and intellectual impairment. Huanglian Jiedu decoction (HLJDD) is the classic representative of clearing heat and detoxifying. This study aimed to explore the effects and possible mechanisms of HLJDD on brain injury in chronic alcohol-exposed mice. Methods: The alcohol-exposed mice were treated with different doses of HLJDD to observe behavioral changes, hippocampal Aß1-42 deposition, number and ultrastructural changes of neurons in the hippocampus and prefrontal cortex, and expressions of synaptic proteins. On this basis, transcriptome sequencing was used to analyze the differentially expressed genes in different treatment groups, and functional enrichment analysis was performed. Then, WB and RT-PCR were used to verify the expression of the pathway. Results: Chronic alcohol exposure reduced body weight in mice, led to motor cognitive impairment, increased Aß1-42 in the hippocampus, decreased the number of neurons in the hippocampus and prefrontal cortex, and the expression of PSD95 and SYN in the hippocampus. HLJDD significantly improved the cognitive dysfunction of mice and alleviated the damage of the hippocampus and prefrontal cortex. Transcriptome sequencing results showed that the regulatory effects of HLJDD on chronic alcohol-exposed mice may be related to the RAS pathway. Further experiments confirmed that chronic alcohol exposure caused a significant increase in protein and gene expressions of the RAS-RAF-MEK-ERK pathway in mouse, and this activation was reversed by HLJDD. Conclusion: HLJDD may ameliorate brain damage caused by chronic alcohol exposure by regulating the RAS-RAF-MEK-ERK pathway.

CRKL but not CRKII contributes to hemin-induced erythroid differentiation of CML.

Destruction of erythropoiesis process leads to various diseases, including thrombocytopenia, anaemia, and leukaemia. miR-429-CT10 regulation of kinase-like (CRKL) axis involved in development, progression and metastasis of cancers. However, the exact role of miR-429-CRKL axis in leukaemic cell differentiation are still unknown. The current work aimed to uncover the effect of miR-429-CRKL axis on erythropoiesis. In the present study, CRKL upregulation was negatively correlated with miR-429 downregulation in both chronic myeloid leukaemia (CML) patient and CR patient samples. Moreover, CRKL expression level was significantly decreased while miR-429 expression level was increased during the erythroid differentiation of K562 cells following hemin treatment. Functional investigations revealed that overexpression and knockdown of CRKL was remarkably effective in suppressing and promoting hemin-induced erythroid differentiation of K562 cells, whereas, miR-429 exhibited opposite effects to CRKL. Mechanistically, miR-429 regulates erythroid differentiation of K562 cells by downregulating CRKL via selectively targeting CRKL-3'-untranslated region (UTR) through Raf/MEK/ERK pathway. Conversely, CRKII had no effect on erythroid differentiation of K562 cells. Taken together, our data demonstrated that CRKL (but not CRKII) and miR-429 contribute to development, progression and erythropoiesis of CML, miR-429-CRKL axis regulates erythropoiesis of K562 cells via Raf/MEK/ERK pathway, providing novel insights into effective diagnosis and therapy for CML patients.

Inhibition of the RAF/MEK/ERK Signaling Cascade in Pancreatic Cancer: Recent Advances and Future Perspectives.

Pancreatic cancer represents a formidable challenge in oncology, primarily due to its aggressive nature and limited therapeutic options. The prognosis of patients with pancreatic ductal adenocarcinoma (PDAC), the main form of pancreatic cancer, remains disappointingly poor with a 5-year overall survival of only 5%. Almost 95% of PDAC patients harbor Kirsten rat sarcoma virus (KRAS) oncogenic mutations. KRAS activates downstream intracellular pathways, most notably the rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling axis. Dysregulation of the RAF/MEK/ERK pathway is a crucial feature of pancreatic cancer and therefore its main components, RAF, MEK and ERK kinases, have been targeted pharmacologically, largely by small-molecule inhibitors. The recent advances in the development of inhibitors not only directly targeting the RAF/MEK/ERK pathway but also indirectly through inhibition of its regulators, such as Src homology-containing protein tyrosine phosphatase 2 (SHP2) and Son of sevenless homolog 1 (SOS1), provide new therapeutic opportunities. Moreover, the discovery of allele-specific small-molecule inhibitors against mutant KRAS variants has brought excitement for successful innovations in the battle against pancreatic cancer. Herein, we review the recent advances in targeted therapy and combinatorial strategies with focus on the current preclinical and clinical approaches, providing critical insight, underscoring the potential of these efforts and supporting their promise to improve the lives of patients with PDAC.

miR-451a suppresses the proliferation and migration of high-grade serous ovarian cancer by targeting RAB5A through the Ras/Raf/MEK/ERK pathway.

BACKGROUND: Ovarian cancer is one of the most common cancers in women. Profiles changes of microRNAs (miRNAs) are closely linked to malignant tumors. In the present study, we investigated expression of miR-451a in high-grade serous ovarian cancer (HGSOC). We also investigated the potential pathological roles and the likely mechanism of miR-451a in the development of HGSOC using animal models and cell lines. METHODS: Using bioinformatics techniques and a real-time PCR, we analyzed differently expressed miRNAs in HGSOC compared to normal tissue. MTT (i.e. 3-[4, 5-dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide), EDU (i.e. 5-ethynyl-2'-deoxyuridine) and transwell assays were performed to investigate the effect of miR-451a on the proliferation and migration of HGSOC SKOV-3 cells. A dual luciferase reporter assay was performed to verify the targeting relationship of miR-451 and RAB5A (one of the Rab GTPase proteins that regulates endocytosis and vesicle transport). Also, we analyzed levels of the RAB5A mRNA and protein by real-time PCR, western blotting and immunohistochemistry assays in HGSOC cells and tissues. Finally, we performed in vivo experiments using HGSOC mice. RESULTS: miR-451a was substantially upregulated in HGSOC and associated with favorable clinical characteristics. miR-451a knockdown significantly increased growth and metastasis of HGSOC cell line SKOV-3 through Ras/Raf/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling. In addition, RAB5A, an early endosome marker, was shown to be a direct target of miR-451a. Moreover, RAB5A is correlated with unfavorable clinical features and shows independent prognostic significance in HGSOC. CONCLUSIONS: We found that the miR-451a/RAB5A axis is associated with tumorigenesis and progression through the Ras/Raf/MEK/ERK pathway, providing prognostic indicators and therapeutic targets for patients with HGSOC.

Influenza A virus replication has a stronger dependency on Raf/MEK/ERK signaling pathway activity than SARS-CoV-2.

The recent COVID-19 pandemic again highlighted the urgent need for broad-spectrum antivirals, both for therapeutic use in acute viral infection and for pandemic preparedness in general. The targeting of host cell factors hijacked by viruses during their replication cycle presents one possible strategy for development of broad-spectrum antivirals. By inhibiting the Raf/MEK/ERK signaling pathway, a central kinase cascade of eukaryotic cells, which is being exploited by numerous viruses of different virus phyla, the small-molecule MEK inhibitor zapnometinib has the potential to address this need. We here performed a side-by-side comparison of the antiviral efficacy of zapnometinib against IAV and SARS-CoV-2 to determine the concentration leading to 50% of its effect on the virus (EC50) and the concentration leading to 50% reduction of ERK phosphorylation (IC50) in a comparable manner, using the same experimental conditions. Our results show that the EC50 value and IC50 value of zapnometinib are indeed lower for IAV compared to SARS-CoV-2 using one representative strain for each. The results suggest that IAV's replication has a stronger dependency on an active Raf/MEK/ERK pathway and, thus, that IAV is more susceptible to treatment with zapnometinib than SARS-CoV-2. With zapnometinib's favorable outcome in a recent phase II clinical trial in hospitalized COVID-19 patients, the present results are even more promising for an upcoming phase II clinical trial in severe influenza virus infection.

Unraveling the interplay between RAS/RAF/MEK/ERK signaling pathway and autophagy in cancer: From molecular mechanisms to targeted therapy.

RAS/RAF/MEK/ERK signaling pathway is one of the most important pathways of Mitogen-activated protein kinases (MAPK), which widely participate in regulating cell proliferation, differentiation, apoptosis and signaling transduction. Autophagy is an essential mechanism that maintains cellular homeostasis by degrading aged and damaged organelles. Recently, some studies revealed RAS/RAF/MEK/ERK signaling pathway is closely related to autophagy regulation and has a dual effect in tumor cells. However, the specific mechanism by which RAS/RAF/MEK/ERK signaling pathway participates in autophagy regulation is not fully understood. This article provides a comprehensive review of the research progress with regard to the RAS/RAF/MEK/ERK signaling pathway and autophagy, as well as their interplay in cancer therapy. The impact of small molecule inhibitors that target the RAS/RAF/MEK/ERK signaling pathway on autophagy is discussed in this study. The advantages and limitations of the clinical combination of these small molecule inhibitors with autophagy inhibitors are also explored. The findings from this study may provide additional perspectives for future cancer treatment strategies.

Quercetin-targeted AKT1 regulates the Raf/MEK/ERK signaling pathway to protect against doxorubicin-induced nephropathy in mice.

BACKGROUND: Doxorubicin is an anthracycline antitumor agent commonly used in clinical practice, which has some nephrotoxicity and is often used to establish mouse models of kidney injury for basic medical research. This study will investigate the protective effect of quercetin on renal function in doxorubicin-induced nephropathy mice. METHODS: C57BL/6 mice were divided into control, model, and quercetin low-, and high-dose groups. Serum and urine were collected to analyze markers of kidney function. H&E staining was used to detect pathological changes in renal tissues. Transmission electron microscopy was performed to observe the ultrastructural changes in renal tissues. Immunohistochemistry was performed to detect the changes of Ang II. RT-qPCR was performed to detect the changes of cytokines. ELISA was used to detect changes in serum inflammatory factors. Molecular docking was performed to verify the targeting relationship between quercetin and AKT1. Western blot was performed to detect Bax, Bcl-2, Cyt-c, AKT1, Raf, MEK, and ERK proteins. RESULTS: Quercetin could induce the recovery of kidney function in kidney-injured mice; H&E results showed that kidney tissue damage and tissue fibrosis were reduced in kidney-injured mice under quercetin. The mitochondrial swollen structure was destroyed by doxorubicin, while the mitochondrial structure was restored under quercetin. The levels of abnormal apoptotic proteins Bax and Bcl-2 were regulated to normal by quercetin. The high expression of Ang II caused by doxorubicin was down-regulated by quercetin. Abnormal inflammatory factors caused by doxorubicin were reversed by quercetin. Western blot experiments showed that quercetin regulated the protein levels of AKT1 and Raf/MEK/ERK and inhibited the detrimental effects of doxorubicin. CONCLUSION: Quercetin may mitigate doxorubicin-induced kidney injury in mice by regulating renal cell inflammatory factors and Raf/MEK/ERK signaling pathway through AKT1 to promote recovery of renal function.

Effect of electroacupuncture on urodynamics and Raf/MEK/ERK signaling pathway in spinal cord tissue of rats with detrusor hyperreflexia after suprasacral spinal cord injury. / ç”µé’ˆå¯¹éª¶ä¸Šè„Šé«“æŸä¼¤åŽé€¼å°¿è‚Œåå°„äº¢è¿›åž‹å¤§é¼ å°¿æµåŠ¨åŠ›å­¦åŠè„Šé«“Raf/MEK/ERK信号通路的影响.

OBJECTIVES: To observe the effect of electroacupuncture (EA) on urodynamics and Raf/MEK/ERK signaling pathway in spine cord tissue of rats after suprasacral spinal cord injury (SSCI), so as to explore its possible mechanism in improving bladder function in rats with detrusor hyperreflexia after SSCI. METHODS: Female SD rats were randomly divided into blank, sham operation, model, EA and EA+PD98059 groups, with 12 rats in each group. Thorax (T) 10 spinal cord transection was performed by surgery. Rats in the EA group were given EA (10 Hz/50 Hz, 20 min) at "Ciliao" (BL32), "Zhongji" (CV3), "Sanyinjiao" (SP6) and "Dazhui" (GV14) once daily for 7 d. Rats of the EA+PD98059 group received intraperitoneal injection of PD98059 (5 mg/kg) 2 h before EA intervention. The urodyna-mics was used to measure the base pressure, leak point pressure, maximum pressure, maximum capacity and comp-liance of bladder, and the morphology of bladder detrusor tissue was observed with HE staining. The TUNEL staining was used to detect the cell apoptosis of the spinal cord tissue. The expression levels of exchange protein directly activated by cAMP 2 (Epac2), Rap, phosphorylated rapidly accelerated fibrosarcoma (p-Raf), phosphorylated mitogen-activated extracellular signal-regulated kinase (p-MEK), phosphorylated extracellular signal regulated kinase 1 and 2 (p-ERK1/2), B-cell lymphoma-2 (Bcl-2), and Bcl-2 associated X protein (Bax) were determined by Western blot. RESULTS: Compared with the sham operation group, the base pressure, leak point pressure and maximum pressure of bladder were significantly increased (P<0.01), the maximum bladder capacity and bladder compliance were decreased (P<0.01), the cell apoptosis rate of spinal cord tissue was increased (P<0.01), and the expression levels of Epac2, Rap, p-Raf, p-MEK, p-ERK1/2, and Bcl-2 protein in spinal cord tissue were decreased (P<0.01), while the expression level of Bax protein was increased (P<0.01) in the model group. After the treatment and compared with the model group, the base pressure, leak point pressure and maximum pressure of bladder, the cell apoptosis rate of spinal cord tissue, the expression level of Bax protein were decreased (P<0.05) in the EA group, while the maximum bladder capacity and bladder compliance, the expression levels of Epac2, Rap, p-Raf, p-MEK, p-ERK1/2, and Bcl-2 protein in spinal cord tissue were all increased (P<0.05, P<0.01). In comparison with the EA group, the base pressure, leak point pressure and maximum pressure of bladder, the cell apoptosis rate, the expression level of Bax protein were significantly increased (P<0.05), whereas the maximum bladder capacity, bladder compliance, and the expression levels of p-MEK, p-ERK1/2, and Bcl-2 protein were decreased (P<0.05) in the EA+PD98059 group. Results of HE staining showed disordered transitional epithelial cells and destroyed lamina propria in bladder detrusor tissue, with the infiltration of monocytes in the model group, which was obviously milder in both EA and EA+PD98059 groups, especially in the EA group. CONCLUSIONS: EA can improve the bladder function in detrusor hyperreflexia rats after SSCI, which may be related to its effect in up-regulating Epac2 and Rap, activating the Raf-MEK-ERK pathway, and reducing the cell apoptosis of spinal cord tissue.

The mechanism of acrolein exposure inhibited the release of neutrophil extracellular traps: By reducing respiratory burst and Raf/MEK/ERK pathway and promote cell apoptosis.

Acrolein (AC) is a highly toxic volatile substance in the environment, and studies have found that excessive AC had a toxic effect on the immune system. Neutrophils are the first line of defense against pathogen invasion. The release of neutrophil extracellular traps (NETs) is a protective mechanism for neutrophils, and its release is affected by environmental pollutants. However, the effect of AC on NETs release and its mechanism remains unclear. In this study, chicken peripheral blood neutrophils were pretreated with 20 µM AC and treated with 5 µM Phorbol 12-myristate 13-acetate (PMA) to stimulate the release of NETs. The results showed that AC exposure significantly inhibited the release of NETs induced by PMA, respiratory burst, and the expression levels of phospho-rapidly accelerated fibrosarcoma (p-Raf), phospho-mitogen-activated extracellular signal-regulated kinase (p-MEK) and phospho-extracellular regulated protein kinases (p-ERK). In addition, AC exposure significantly inhibited the expression of B-cell lymphoma-2 (Bcl-2) and promoted the expression of apoptotic factors Bcl2-Associated X (Bax), cytochrome c (Cyt C), cysteinyl aspartate specific proteinase 9 (Casp 9) and cysteinyl aspartate specific proteinase 3 (Casp 3). Further inhibition of neutrophil apoptosis significantly improved the release of NETs. The above results indicated that AC exposure led to a decrease in the formation of NETs, which is caused by excessive AC-induced neutrophil apoptosis. Our study clarified the immune toxicity mechanism of AC on chickens, which is of great significance and reference value for protecting the ecological environment and poultry health.

RNF173 suppresses RAF/MEK/ERK signaling to regulate invasion and metastasis via GRB2 ubiquitination in Hepatocellular Carcinoma.

BACKGROUND: The role of the membrane-associated RING-CH (MARCH) family in carcinogenesis has been widely studied, but the member of this family, RNF173, has not yet been thoroughly explored in the context of hepatocellular carcinoma (HCC). METHODS: With the use of an HCC tissue microarray and IHC staining, we aim to determine the differential expression of RNF173 in HCC patients and its clinical significance. The biological role of RNF173 is investigated through in vitro and in vivo experiments. RNA sequencing, mass spectrometry, and immunoprecipitation are performed to uncover the underlying mechanism of RNF173's impact on the development of HCC. RESULTS: The mRNA and protein levels of RNF173 were significantly lower in HCC tissues than in normal tissues. HCC patients with low RNF173 expression had shorter overall survival and recurrence-free survival, and RNF173 was significantly correlated with tumor number, tumor capsule, tumor differentiation, and BCLC stage. In addition, in vitro and in vivo experiments showed that RNF173 downregulation exacerbated tumor progression, including migration, invasion, and proliferation. GRB2 is a key molecule in the RAF/MEK/ERK pathway. RNF173 inhibits the RAF/MEK/ERK signaling by ubiquitinating and degrading GRB2, thereby suppressing HCC cell proliferation, invasion and migration. Combining clinical samples, we found that HCC patients with high RNF173 and low GRB2 expression had the best prognosis. CONCLUSION: RNF173 inhibits the invasion and metastasis of HCC by ubiquitinating and degrading GRB2, thereby suppressing the RAF/MEK/ERK signaling pathway. RNF173 is an independent risk factor for the survival and recurrence of HCC patients. RNF173 may serve as a novel prognostic molecule and potential therapeutic target for HCC. Video Abstract Graphical abstract Model of RNF173 on RAF/MEK/ERK signaling. RNF173 knockdown resulted in impaired ubiquitination and degradation of GRB2, leading to the activation of the RAF/MEK/ERK signaling pathway and promotion of invasion and metastasis in HCC cells.

Preclinical evaluation of Mito-LND, a targeting mitochondrial metabolism inhibitor, for glioblastoma treatment.

BACKGROUND: Glioblastoma (GBM) is a brain tumor with the highest level of malignancy and the worst prognosis in the central nervous system. Mitochondrial metabolism plays a vital role in the occurrence and development of cancer, which provides critical substances to support tumor anabolism. Mito-LND is a novel small-molecule inhibitor that can selectively inhibit the energy metabolism of tumor cells. However, the therapeutic effect of Mito-LND on GBM remains unclear. METHODS: The present study evaluated the inhibitory effect of Mito-LND on the growth of GBM cells and elucidated its potential mechanism. RESULTS: The results showed that Mito-LND could inhibit the survival, proliferation and colony formation of GBM cells. Moreover, Mito-LND induced cell cycle arrest and apoptosis. Mechanistically, Mito-LND inhibited the activity of mitochondrial respiratory chain complex I and reduced mitochondrial membrane potential, thus promoting ROS generation. Importantly, Mito-LND could inhibit the malignant proliferation of GBM by blocking the Raf/MEK/ERK signaling pathway. In vivo experiments showed that Mito-LND inhibited the growth of GBM xenografts in mice and significantly prolonged the survival time of tumor-bearing mice. CONCLUSION: Taken together, the current findings support that targeting mitochondrial metabolism may be as a potential and promising strategy for GBM therapy, which will lay the theoretical foundation for further clinical trials on Mito-LND in the future.

BRAF(V600E) mutation together with loss of Trp53 or pTEN drives the origination of hairy cell leukemia from B-lymphocytes.

Hairy cell leukemia (HCL) is a B-lymphoma induced by BRAF(V600E) mutation. However, introducing BRAF(V600E) in B-lymphocytes fails to induce hematological malignancy, suggesting that BRAF(V600E) needs concurrent mutations to drive HCL ontogeny. To resolve this issue, here we surveyed human HCL genomic sequencing data. Together with previous reports, we speculated that the tumor suppressor TP53, P27, or PTEN restrict the oncogenicity of BRAF(V600E) in B-lymphocytes, and therefore that their loss-of-function facilitates BRAF(V600E)-driven HCL ontogeny. Using genetically modified mouse models, we demonstrate that indeed BRAF(V600E)KI together with Trp53KO or pTENKO in B-lymphocytes induces chronic lymphoma with pathological features of human HCL. To further understand the cellular programs essential for HCL ontogeny, we profiled the gene expression of leukemic cells isolated from BRAF(V600E)KI and Trp53KO or pTENKO mice, and found that they had similar but different gene expression signatures that resemble that of M2 or M1 macrophages. In addition, we examined the expression signature of transcription factors/regulators required for germinal center reaction and memory B cell versus plasma cell differentiation in these leukemic cells and found that most transcription factors/regulators essential for these programs were severely inhibited, illustrating why hairy cells are arrested at a transitional stage between activated B cells and memory B cells. Together, our study has uncovered concurrent mutations required for HCL ontogeny, revealed the B cell origin of hairy cells and investigated the molecular basis underlying the unique pathological features of the disease, with important implications for HCL research and treatment.

Raf/MEK/ERK Signaling Pathway Is Involved in the Inhibition of Glioma Cell Proliferation and Invasion in the Ketogenic Microenvironment.

OBJECTIVE: A high-fat, low-carbohydrate ketogenic diet has been used to treat malignant glioma, in which the Raf/MEK/ERK signaling pathway is overactivated. However, whether the Raf/MEK/ERK signaling pathway is involved in the therapeutic effect of ketone bodies remains unknown. In this study, we investigated the effects of a major ketone body, 3-hydroxybutyric acid (3-HBA), on the proliferation and metastasis of malignant glioblastoma cells and the underlying mechanism. METHODS: Two human malignant glioblastoma cell lines (U87 and U251) were treated with different concentrations of 3-HBA with or without the Raf inhibitor PAF C-16 for 24 h. Cell proliferation, cell cycle, cell invasion, and phospholipase D1 (PLD1) activity were determined. Protein and gene expression levels of Raf/MEK/ERK signaling pathway members were examined. RESULTS: 3-HBA significantly decreased cell proliferation, invasion, and intracellular PLD1 activity in both U87 and U251 glioblastoma cell lines. 3-HBA treatment significantly increased the proportion of cells in the G1 phase and decreased the proportion of cells in S phase in U87 cells. In the U251 line, the proportion of treated cells in S phase was increased and proportion of cells in G2 was decreased. 3-HBA treatment also significantly decreased the protein expression levels of Raf, MEK, p-MEK, ERK, p-ERK, and PLD1 while increasing p53 expression; an effect that was similar to treatment with the Raf inhibitor. Co-treatment of 3-HBA with the Raf inhibitor further enhanced the effects of the 3-HBA in both cell lines. CONCLUSION: We confirmed that a ketogenic microenvironment can inhibit glioma cell proliferation and invasion by downregulating the expression of PLD1 through the Raf/MEK/ERK signaling pathway.

The Role of Activation of PI3K/AKT/mTOR and RAF/MEK/ERK Pathways in Aggressive Pituitary Adenomas-New Potential Therapeutic Approach-A Systematic Review.

Pituitary tumors (PT) are mostly benign, although occasionally they demonstrate aggressive behavior, invasion of surrounding tissues, rapid growth, resistance to conventional treatments, and multiple recurrences. The pathogenesis of PT is still not fully understood, and the factors responsible for its invasiveness, aggressiveness, and potential for metastasis are unknown. RAF/MEK/ERK and mTOR signaling are significant pathways in the regulation of cell growth, proliferation, and survival, its importance in tumorigenesis has been highlighted. The aim of our review is to determine the role of the activation of PI3K/AKT/mTOR and RAF/MEK/ERK pathways in the pathogenesis of pituitary tumors. Additionally, we evaluate their potential in a new therapeutic approach to provide alternative therapies and improved outcomes for patients with aggressive pituitary tumors that do not respond to standard treatment. We perform a systematic literature search using the PubMed, Embase, and Scopus databases (search date was 2012-2023). Out of the 529 screened studies, 13 met the inclusion criteria, 7 related to the PI3K/AKT/mTOR pathway, and 7 to the RAF/MEK/ERK pathway (one study was used in both analyses). Understanding the specific factors involved in PT tumorigenesis provides opportunities for targeted therapies. We also review the possible new targeted therapies and the use of mTOR inhibitors and TKI in PT management. Although the RAF/MEK/ERK and PI3K/AKT/mTOR pathways play a pivotal role in the complex signaling network along with many interactions, further research is urgently needed to clarify the exact functions and the underlying mechanisms of these signaling pathways in the pathogenesis of pituitary adenomas and their role in its invasiveness and aggressive clinical outcome.