ERK and c-Myc signaling in host-derived tumor endothelial cells is essential for solid tumor growth

UPS and Kinases-Gatekeepers of the G1/S Transition

The G1/S transition is a highly regulated and pivotal checkpoint in the cell cycle, where the cell decides whether to commit to DNA replication and subsequent division or enter a non-dividing state. This checkpoint serves as a critical control point for preventing uncontrolled cell proliferation and maintaining genomic stability. The major driving force underlying the G1/S transition is the sequential activation of Cyclin-dependent kinases (CDKs), which is regulated by the coordinated binding of Cyclin partners, as well as the phosphorylation and ubiquitin-mediated degradation of both Cyclin partners and Cyclin-dependent kinase inhibitors (CKIs). Various E3 ligase families govern the timely degradation of these regulatory proteins, with their activity intricately controlled by phosphorylation events. This coordination enables the cells to efficiently translate the environmental cues and molecular signaling inputs to determine their fate. We explore the evolution of three distinct models describing the G1/S transition, highlighting how the traditional linear model is being challenged by recent paradigm shifts and conflicting findings. These advances reveal emerging complexity and unresolved questions in the field, particularly regarding how the latest insights into coordinated phosphorylation and ubiquitination-dependent degradation integrate into contemporary models of the G1/S transition.

ERK pathway reactivation prevents anthrax toxin lethality in mice

Lethal toxin (LT), the major virulence factor of Bacillus anthracis, proteolytically inactivates MEKs and disables downstream ERK, p38 and JNK pathway signalling leading to tissue damage and mortality. Therapies for LT-induced damage after host cell internalization of the toxin are lacking. Here we constructed MEK variants in which the LT proteolytic site was modified: MEK2(P10V/A11D), MEK3(I27D) and MEK6(I15D). These variants were resistant to proteolysis by LT. Expression in cells enabled sustained activation of ERK and p38 pathways and promoted cell survival upon LT treatment. Survival of LT- or B. anthracis-challenged MEK variant transgenic mice also increased compared with controls. We found that LT-mediated disruption of both ERK and p38 pathway is essential for anthrax pathogenesis. We show that engagement of upstream receptor tyrosine kinases reactivated the LT-disrupted ERK pathway, as did administering a cocktail of EGF, GM-CSF and FGF2 growth factors, which significantly increased survival of LT- or B. anthracis-challenged mice. These findings offer potential towards developing damage-limiting therapeutic strategies for anthrax.

L-741626 inhibits hepatocellular carcinoma progression by targeting Ref-1 to suppress MAPK/ERK signalling pathway activity

Hepatocellular carcinoma (HCC) is a common and challenging malignancy of the digestive tract. Unfortunately, patients with advanced HCC frequently experience limited long-term benefits from current treatments, highlighting the critical need for innovative therapeutic agents. The discovery and development of new small-molecule compounds that target tumours have become crucial aspects of cancer research. In this study, we report on L-741626, a compound that has significant inhibitory effects on HCC. Both in vivo and in vitro experiments confirmed that L-741626 inhibited the growth of HCC by suppressing the MAPK/ERK signalling pathway. Molecular docking simulations and drug affinity responsive target stability assays further identified redox Factor 1 (Ref-1) as a target of L-741626. Ref-1 is overexpressed in HCC and is correlated with poor prognosis and high stage. Further studies demonstrated that Ref-1 interacts with CRAF, a crucial component of the MAPK/ERK signalling pathway. Knockdown of Ref-1 in HCC cells led to inhibition of the MAPK/ERK pathway. Sorafenib is a well-established targeted therapy for the treatment of HCC, with its primary antitumor mechanism being the inhibition of the MAPK/ERK signalling pathway. However, the presence of tumor stem cells is a key factor contributing to resistance to sorafenib. Our study demonstrates that L-741626 can suppress tumor stemness in HCC. The combination of L-741626 and sorafenib significantly enhances the sensitivity of HCC, resulting in increased tumoricidal effects. Our findings reveal a novel pharmacological effect of L-741626, which inhibits MAPK/ERK signalling activity in HCC by targeting Ref-1. Furthermore, L-741626 exhibits a synergistic effect when combined with sorafenib, suggesting a new potential approach for HCC treatment.

Targeting endothelial MYC using siRNA or miR-218 nanoparticles sensitizes chemo- and immuno-therapies by recapitulating the Notch activation-induced tumor vessel normalization

Background: The chaotic, over-activated tumor vasculature promotes tumor growth and erodes most current therapies. Although Notch activation critically regulates angiogenesis, the broad roles of Notch has dampened its druggability. Methods: Gene-modified mice with a Cdh5-CreERT transgene were employed to activate/block Notch signaling in endothelial cells (ECs). Multiple transcriptome analyses were conducted to compare gene expression profiles. qRT-PCR and western blotting were used to determine gene expression level. Immunofluorescence and flow cytometry were used to observe morphological alterations and immune microenvironment in tumors. Nanoparticles (PEI-PEG-cRGD) were used to deliver siRNA into tumor ECs (TECs) in vivo. Results: Genetic Notch activation or blockade in TECs normalizes or deteriorates tumor vessels, respectively. Single-cell RNA sequencing showed that Notch activation selectively reduced the proliferating TEC subset, which accounted for about 30% of TECs and gave rise to other TEC subsets. Notch activation or blockade downregulated or upregulated MYC, respectively. MYC overexpression canceled Notch activation-induced proliferation arrest of TECs in vitro, and a MYC inhibitor normalized tumor vessels in RBPj deficient mice, suggesting that MYC is the authentic Notch target in normalizing tumor vessels. Nanoparticles encapsulated with MYC siRNA (EC-siMYC) or miR-218 (EC-miR-218), a Notch-downstream miRNA suppressing MYC, were able to mitigate Notch inhibition-induced tumor vessel defects. Combination of cisplatin with MYC blockade exhibited improved therapeutic effects. Moreover, MYC blockade promoted T cell infiltration and enhanced anti-PD1 immunotherapy. Conclusions: Together, our data have demonstrated that Notch activation normalizes tumor vessels by repressing the proliferating TEC subset via MYC, and targeting endothelial MYC using nanoparticles bearing siRNA or miRNA is an efficient strategy for tumor anti-angiogenic therapy.

ATP depletion in anthrax edema toxin pathogenesis

Anthrax lethal toxin (LT) and edema toxin (ET) are two of the major virulence factors of Bacillus anthracis, the causative pathogen of anthrax disease. While the roles of LT in anthrax pathogenesis have been extensively studied, the pathogenic mechanism of ET remains poorly understood. ET is a calmodulin-dependent adenylate cyclase that elevates intracellular cAMP by converting ATP to cAMP. Thus, it was postulated that the ET-induced in vivo toxicity is mediated by certain cAMP-dependent events. However, mechanisms linking cAMP elevation and ET-induced damage have not been established. Cholera toxin is another bacterial toxin that increases cAMP. This toxin is known to cause severe intestinal fluid secretion and dehydration by cAMP-mediated activation of protein kinase A (PKA), which in turn activates cystic fibrosis transmembrane conductance regulator (CFTR). The cAMP-activated PKA phosphorylation of CFTR on the surface of intestinal epithelial cells leads to an efflux of chloride ions accompanied by secretion of H2O into the intestinal lumen, causing rapid fluid loss, severe diarrhea and dehydration. Due to similar in vivo effects, it was generally believed that ET and cholera toxin would exhibit a similar pathogenic mechanism. Surprisingly, in this work, we found that cAMP-mediated PKA/CFTR activation is not essential for ET to exert its in vivo toxicity. Instead, our data suggest that ET-induced ATP depletion may play an important role in the toxin's pathogenesis.

Shared molecular, cellular, and environmental hallmarks in cardiovascular disease and cancer: Any place for drug repurposing?

Cancer and cardiovascular disease (CVD) are the 2 biggest killers worldwide. Specific treatments have been developed for the 2 diseases. However, mutual therapeutic targets should be considered because of the overlap of cellular and molecular mechanisms. Cancer research has grown at a fast pace, leading to an increasing number of new mechanistic treatments. Some of these drugs could prove useful for treating CVD, which realizes the concept of cancer drug repurposing. This review provides a comprehensive outline of the shared hallmarks of cancer and CVD, primarily ischemic heart disease and heart failure. We focus on chronic inflammation, altered immune response, stromal and vascular cell activation, and underlying signaling pathways causing pathological tissue remodeling. There is an obvious scope for targeting those shared mechanisms, thereby achieving reciprocal preventive and therapeutic benefits. Major attention is devoted to illustrating the logic, advantages, challenges, and viable examples of drug repurposing and discussing the potential influence of sex, gender, age, and ethnicity in realizing this approach. Artificial intelligence will help to refine the personalized application of drug repurposing for patients with CVD. SIGNIFICANCE STATEMENT: Cancer and cardiovascular disease (CVD), the 2 biggest killers worldwide, share several underlying cellular and molecular mechanisms. So far, specific therapies have been developed to tackle the 2 diseases. However, the development of new cardiovascular drugs has been slow compared with cancer drugs. Understanding the intersection between pathological mechanisms of the 2 diseases provides the basis for repurposing cancer therapeutics for CVD treatment. This approach could allow the rapid development of new drugs for patients with CVDs.

Synthesis of Thiazolidinedione- and Triazole-Linked Organoselenocyanates and Evaluation of Anticancer Activities Against Breast Cancer with Mechanistic Investigations

Organoselenocyanates are important classes of organoselenium compounds having potential pharmaceutical applications in cancer biology. In the present study, two different series of organoselenocyanates (15 a-15 c and 16 a-16 c) incorporating crucial heterocyclic pharmacophores such as 2,4-thiazolidine-1,3-dione and 1,2,3-triazole were rationally designed. The organoselenocyanates were synthesized using multi-step organic synthesis and investigated for their anticancer activities against triple-negative breast cancer cells. Based on the preliminary anti-proliferative activities and the selectivity index towards cancer cells over the normal cells, 2,4-thiazolidine-1,3-dione-based selenocyanate 15 a was identified as the lead analogue for detailed investigations. In addition to the anti-migratory activity, compound 15 a induced G1-phase arrest of the cell cycle and led to early apoptosis. Further studies on the redox balance of MDA-MB-231 cells indicated the antioxidant nature of 15 a with the quenching of ROS level and upregulation of TrxR1 expression. Detailed mechanistic investigations with the expression levels of key-cancer marker proteins revealed that the selenocyanate 15 a induced the activation of ERK pathway by upregulating p-ERK expression with the subsequent downregulation of p-Akt and c-Myc levels leading to the inhibition of cellular proliferation. Therefore, the primary outcomes of the study would be valuable in the development of chemotherapeutic agents towards the treatment of triple-negative breast cancer.

Anthrax lethal toxin exerts potent metabolic inhibition of the cardiovascular system

Bacillus anthracis causes anthrax through a combination of bacterial infection and toxemia. As a major virulence factor of B. anthracis, anthrax lethal toxin (LT) is a zinc-dependent metalloproteinase, exerting its cytotoxicity through proteolytic cleavage of the mitogen-activated protein kinase kinases, thereby shutting down the MAPK pathways. Anthrax lethal toxin induces host lethality mostly by targeting the cardiovascular system. Although the enzymatic activity and the molecular targets of LT have long been known, the detailed mechanisms underlying cellular/tissue/organ toxicity are still poorly understood. In this work, we sought to investigate the mechanism of LT-induced cellular damage in the cardiovascular system. We demonstrate for the first time that anthrax lethal toxin has potent inhibitory effects on the central metabolism of cardiomyocytes and endothelial cells. This is likely due to the observed downregulating of c-Myc expression through the toxin-induced inhibition of the ERK pathway. Since c-Myc is a master transcription factor controlling the expression of many rate-limiting metabolic enzymes in glycolysis and the tricarboxylic acid cycle, LT's downregulation of c-Myc may lead to the observed bioenergetic collapse, particularly, in cardiomyocytes. Since cardiac cell contraction requires continuous production of large amounts of ATP, potent inhibition of the bioenergetics of cardiomyocytes would be incompatible with life. Thus, LT-induced lethality through targeting cardiomyocytes and endothelial cells appears to be a consequence of a bioenergetic collapse, likely due to the toxin's potent inhibitory activity on the MEK-ERK-c-Myc-metabolic/bioenergetic axis within these target cells of cardiovascular system.IMPORTANCEAnthrax lethal toxin (LT) is a major virulence factor of Bacillus anthracis, the causative pathogen of anthrax disease. Anthrax lethal toxin is a metalloproteinase that cleaves and inactivates MEKs, thereby shutting down MAPK pathways, leading to host mortality primarily through targeting of the cardiovascular system. However, the detailed mechanisms underlying the toxin's cellular and tissue toxicity are still poorly understood. Here, we found that anthrax lethal toxin has potent inhibitory activity on glycolysis and oxidative phosphorylation of cardiomyocytes and endothelial cells. These effects appear to be the consequence of downregulation of c-Myc, a master transcription factor that controls many rate-limiting enzymes of glycolysis and the tricarboxylic acid cycle. With the high demand on energy for cardiac contraction, the potent inhibition of cardiomyocyte metabolism by LT would be incompatible with life. This work provides critical insights into why the cardiovascular system is the major in vivo target of LT-induced lethality.

Zuojin Pill Alleviates Precancerous Lesions of Gastric Cancer by Modulating the MEK/ERK/c-Myc Pathway: An Integrated Approach of Network Pharmacology, Molecular Dynamics Simulation, and Experimental Validation

Background

Precancerous lesions of gastric cancer (PLGC) represent critical stages in gastric cancer progression, with a high risk of malignancy. Current treatments, such as Helicobacter pylori eradication, show limited efficacy in reversing precancerous molecular changes. Zuojin Pill (ZJP), a traditional Chinese medicine, has demonstrated potential for treating digestive disorders and may offer a promising approach for PLGC intervention.

Objective

This study aims to investigate the therapeutic effects and mechanisms of ZJP in treating PLGC, focusing on its active components, target pathways, and molecular interactions. By using advanced analytical techniques, we provide a scientific foundation for ZJP's potential application in early gastric cancer intervention.

Methods

Using ultra-high performance liquid chromatography-quadrupole orbitrap high-resolution mass spectrometry (UPLC-Q-Orbitrap HRMS), we identified active components in ZJP. A network pharmacology approach was then applied to construct a "ZJP-compound-target-disease" network. Molecular docking and molecular dynamics simulations were conducted to analyze the stability and interactions of the main active components of ZJP with core protein targets in PLGC. Animal experiments were used to validate significant targets and pathways in vivo.

Results

Tangeritin, Isorhamnetin, Caffeic Acid, Azelaic Acid, and Adenosine were identified as the main active components of ZJP in the treatment of PLGC, with key targets including PIK3R1, MAPK3, SRC, JAK2, STAT3, and PIK3CA. Molecular docking and molecular dynamics simulations further confirmed the relationship between compounds and target proteins. The potential molecular mechanism of ZJP predicted by network pharmacology analysis was confirmed in PLGC rats. ZJP downregulated IL-6, TNF-α, c-myc, p-MEK1 and p-ERK1/2, effectively reversing the progression of PLGC.

Conclusion

ZJP can reverse MNNG-induced PLGC, potentially through inhibition of the MEK/ERK/c-myc pathway and regulation of cellular proliferation and apoptosis.

Activation of MEK-ERK-c-MYC signaling pathway promotes splenic M2-like macrophage polarization to inhibit PHcH-liver cirrhosis

INTRODUCTION

Portal hypertension combined with hypersplenism (PHcH) is the main cause of hypocytosis and esophagogastric variceal hemorrhage in patients with liver cirrhosis. Activated macrophages that destroy excess blood cells are the main cause of hypersplenism, but the activating pathway is not very clear. This study aims to investigate the activation types of splenic macrophages and their activation mechanisms, to provide experimental evidence for the biological treatment of splenomegaly, and to find a strategy to improve liver fibrosis and inflammation by intervening in splenic immune cells. This study revealed the occurrence of M2-like polarization of macrophages and upregulation of c-Myc gene expression in the PH spleen.

METHODS

RNAseq, protein chip, western blot, and chip-seq were performed on macrophages and the in vitro MEK inhibitor rafametinib was used. Carbon tetrachloride and thioacetamide induced mouse cirrhosis models were separately constructed.

RESULTS

c-Myc gene knockout in splenic macrophages reduced M2-like polarization and exacerbated liver fibrosis inflammation. c-Myc activated the MAPK signaling pathway and upregulated the expression of IL-4 and M2-like related genes in PH hypersplenism through the MEK-ERK-c-Myc axis. In addition, the c-Myc gene exerted anti-inflammatory effects by upregulating IL-4-mediated signal transduction to promote M2-like differentiation and anti-inflammatory cytokine secretion.

CONCLUSIONS

Activation of MEK-ERK-c-MYC signaling pathway promotes splenic M2-like macrophage polarization to inhibit PHcH-liver cirrhosis. Therefore, the induction of macrophage depolarization might represent a new therapeutic approach in the cure of PH hypersplenism, making c-Myc a potential candidate for macrophage polarization therapy.

Vilazodone Alleviates Neurogenesis-Induced Anxiety in the Chronic Unpredictable Mild Stress Female Rat Model: Role of Wnt/β-Catenin Signaling

Defective β-catenin signaling is accompanied with compensatory neurogenesis process that may pave to anxiety. β-Catenin has a distinct role in alleviating anxiety in adolescence; however, it undergoes degradation by the degradation complex Axin and APC. Vilazodone (VZ) is a fast, effective antidepressant with SSRI activity and 5-HT1A partial agonism that amends somatic and/or psychic symptoms of anxiety. Yet, there is no data about anxiolytic effect of VZ on anxiety-related neurogenesis provoked by stress-reduced β-catenin signaling. Furthermore, females have specific susceptibility toward psychopathology. The aim of the present study is to uncover the molecular mechanism of VZ relative to Wnt/β-catenin signaling in female rats. Stress-induced anxiety was conducted by subjecting the rats to different stressful stimuli for 21 days. On the 15th day, stressed rats were treated with VZ(10 mg/kg, p.o.) alone or concomitant with the Wnt inhibitor: XAV939 (0.1 mg/kg, i.p.). Anxious rats showed low β-catenin level turned over by Axin-1 with unanticipated reduction of APC pursued with elevated protein levels of neurogenesis-stimulating proteins: c-Myc and pThr183-Erk likewise gene expressions of miR-17-5p and miR-18. Two weeks of VZ treatment showed anxiolytic effect figured by alleviation of hippocampal histological examination. VZ protected β-catenin signal via reduction in Axin-1 and elevation of APC conjugated with modulation of β-catenin downstream targets. The cytoplasmic β-catenin turnover by Axin-1 was restored by XAV939. Herein, VZ showed anti-anxiety effect, which may be in part through regaining the balance of the reduced β-catenin and its subsequent exaggerated response of p-Erk, c-Myc, Dicer-1, miR-17-5p, and miR-18.

PPP1r18 promotes tumor progression in esophageal squamous cell carcinoma by regulating the calcineurin-mediated ERK pathway

Esophageal cancer is one of the most common malignant tumors, and the 5-year overall survival rate is only 20%. Esophageal squamous cell carcinoma (ESCC) is the primary histological type of esophageal carcinoma in China. Protein phosphatase 1 regulatory subunit 18 (PPP1r18) is one of the actin-regulatory proteins and is able to bind to protein phosphatase 1 catalytic subunit alpha (PPP1CA). Yet, little is known about the role of PPP1r18 in ESCC. This study aimed to elucidate the biological functions of PPP1r18 in the ESCC progression. Clinical samples first confirmed that PPP1r18 expression was upregulated in ESCC, and PPP1r18 was correlated with tumor invasion depth, lymph node metastasis, distant metastasis and reduced overall survival. We then observed that PPP1r18 overexpression enhanced cell proliferation in vitro and in vivo. Mechanistically, PPP1r18 regulated tumor progression of ESCC through activating the calcineurin-mediated ERK pathway, rather than binding to PPP1CA. Collectively, our results suggest that PPP1r18 promotes ESCC progression by regulating the calcineurin-mediated ERK pathway. PPP1r18 might be a potential target for the diagnosis and treatment of ESCC.

A positive feedback loop between PFKP and c-Myc drives head and neck squamous cell carcinoma progression

BACKGROUND

The aberrant expression of phosphofructokinase-platelet (PFKP) plays a crucial role in the development of various human cancers by modifying diverse biological functions. However, the precise molecular mechanisms underlying the role of PFKP in head and neck squamous cell carcinoma (HNSCC) are not fully elucidated.

METHODS

We assessed the expression levels of PFKP and c-Myc in tumor and adjacent normal tissues from 120 HNSCC patients. A series of in vitro and in vivo experiments were performed to explore the impact of the feedback loop between PFKP and c-Myc on HNSCC progression. Additionally, we explored the therapeutic effects of targeting PFKP and c-Myc in HNSCC using Patient-Derived Organoids (PDO), Cell Line-Derived Xenografts, and Patients-Derived Xenografts.

RESULTS

Our findings indicated that PFKP is frequently upregulated in HNSCC tissues and cell lines, correlating with poor prognosis. Our in vitro and in vivo experiments demonstrate that elevated PFKP facilitates cell proliferation, angiogenesis, and metastasis in HNSCC. Mechanistically, PFKP increases the ERK-mediated stability of c-Myc, thereby driving progression of HNSCC. Moreover, c-Myc stimulates PFKP expression at the transcriptional level, thus forming a positive feedback loop between PFKP and c-Myc. Additionally, our multiple models demonstrate that co-targeting PFKP and c-Myc triggers synergistic anti-tumor effects in HNSCC.

CONCLUSION

Our study demonstrates the critical role of the PFKP/c-Myc positive feedback loop in driving HNSCC progression and suggests that simultaneously targeting PFKP and c-Myc may be a novel and effective therapeutic strategy for HNSCC.

A network pharmacology-based approach to explore the molecular mechanism of Aidi injection against prostate cancer

Objective

To explore the molecular mechanism of Aidi injection in the treatment of prostate cancer (PCa).

Materials and methods

CCK-8 and colony formation assays were used to detect the effects of Aidi on PC3 and DU145 cells; effects on the cell cycle and apoptosis of DU145 cells were detected by flow cytometry; effects on migration and invasion of PC3 and DU145 cells were detected by wound healing and transwell assay, respectively. The main active components of Aidi, their corresponding targets, and PCa associated pathways were predicted and analyzed by network pharmacology. Then predicted key targets and related signaling pathways were further verified by western blotting. The potential active components of Aidi were predicted by molecular docking technology.

Results

Aidi significantly inhibited the proliferation, colony formation, migration, and invasion of PC3 and DU145 cells; Aidi induced apoptosis and cell cycle G2/M phase arrest of DU145 cells. Network pharmacology analysis yielded 36 potential core targets of Aidi against PCa, and the top 10 signaling pathways including MAPK, PI3K-Akt, and HIF-1α and so on were enriched. Western blotting confirmed that Aidi upregulated the expression levels of p-JNK, p-p38, p-ERK, and ERK in DU145 cells. Molecular docking study showed that kaempferol, (Z)-1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one, 7-O-methylisomucronulatol, calycosin, and N-salicylidene-salicylamine can be well binding with JNK and p38.

Conclusion

Aidi could inhibit PCa cell proliferation and metastasis through induction of apoptosis and cell cycle arrest, which may be related to activating JNK and p38 signaling pathway.

Design, Synthesis, and Anti-Leukemic Evaluation of a Series of Dianilinopyrimidines by Regulating the Ras/Raf/MEK/ERK and STAT3/c-Myc Pathways

Although the long-term survival rate for leukemia has made significant progress over the years with the development of chemotherapeutics, patients still suffer from relapse, leading to an unsatisfactory outcome. To discover the new effective anti-leukemia compounds, we synthesized a series of dianilinopyrimidines and evaluated the anti-leukemia activities of those compounds by using leukemia cell lines (HEL, Jurkat, and K562). The results showed that the dianilinopyrimidine analog H-120 predominantly displayed the highest cytotoxic potential in HEL cells. It remarkably induced apoptosis of HEL cells by activating the apoptosis-related proteins (cleaved caspase-3, cleaved caspase-9 and cleaved poly ADP-ribose polymerase (PARP)), increasing apoptosis protein Bad expression, and decreasing the expression of anti-apoptotic proteins (Bcl-2 and Bcl-xL). Furthermore, it induced cell cycle arrest in G2/M; concomitantly, we observed the activation of p53 and a reduction in phosphorylated cell division cycle 25C (p-CDC25C) / Cyclin B1 levels in treated cells. Additionally, the mechanism study revealed that H-120 decreased these phosphorylated signal transducers and activators of transcription 3, rat sarcoma, phosphorylated cellular RAF proto-oncogene serine / threonine kinase, phosphorylated mitogen-activated protein kinase kinase, phosphorylated extracellular signal-regulated kinase, and cellular myelocytomatosis oncogene (p-STAT3, Ras, p-C-Raf, p-MEK, p-MRK, and c-Myc) protein levels in HEL cells. Using the cytoplasmic and nuclear proteins isolation assay, we found for the first time that H-120 can inhibit the activation of STAT3 and c-Myc and block STAT3 phosphorylation and dimerization. Moreover, H-120 treatment effectively inhibited the disease progression of erythroleukemia mice by promoting erythroid differentiation into the maturation of erythrocytes and activating the immune cells. Significantly, H-120 also improved liver function in erythroleukemia mice. Therefore, H-120 may be a potential chemotherapeutic drug for leukemia patients.

Identification of COQ2 as a regulator of proliferation and lipid peroxidation through genome-scale CRISPR-Cas9 screening in myeloma cells

Multiple myeloma (MM) is the second most common malignant haematological disease with a poor prognosis. The limit therapeutic progress has been made in MM patients with cancer relapse, necessitating deeper research into the molecular mechanisms underlying its occurrence and development. A genome-wide CRISPR-Cas9 loss-of-function screening was utilized to identify potential therapeutic targets in our research. We revealed that COQ2 plays a crucial role in regulating MM cell proliferation and lipid peroxidation (LPO). Knockout of COQ2 inhibited cell proliferation, induced cell cycle arrest and reduced tumour growth in vivo. Mechanistically, COQ2 promoted the activation of the MEK/ERK cascade, which in turn stabilized and activated MYC protein. Moreover, we found that COQ2-deficient MM cells increased sensitivity to the LPO activator, RSL3. Using an inhibitor targeting COQ2 by 4-CBA enhanced the sensitivity to RSL3 in primary CD138+ myeloma cells and in a xenograft mouse model. Nevertheless, co-treatment of 4-CBA and RSL3 induced cell death in bortezomib-resistant MM cells. Together, our findings suggest that COQ2 promotes cell proliferation and tumour growth through the activation of the MEK/ERK/MYC axis and targeting COQ2 could enhance the sensitivity to ferroptosis in MM cells, which may be a promising therapeutic strategy for the treatment of MM patients.

Efficacy of Butyrate to Inhibit Colonic Cancer Cell Growth Is Cell Type-Specific and Apoptosis-Dependent

Increasing dietary fiber consumption is linked to lower colon cancer incidence, and this anticancer effect is tied to elevated levels of short-chain fatty acids (e.g., butyrate) because of the fermentation of fiber by colonic bacteria. While butyrate inhibits cancer cell proliferation, the impact on cancer cell type remains largely unknown. To test the hypothesis that butyrate displays different inhibitory potentials due to cancer cell type, we determined half-maximal inhibitory concentrations (IC50) of butyrate in HCT116, HT-29, and Caco-2 human colon cancer cell proliferation at 24, 48, and 72 h. The IC50 (mM) butyrate concentrations of HCT116, HT-29, and Caco-2 cells were [24 h, 1.14; 48 h, 0.83; 72 h, 0.86], [24 h, N/D; 48 h, 2.42; 72 h, 2.15], and [24 h, N/D; 48 h, N/D; 72 h, 2.15], respectively. At the molecular level, phosphorylated ERK1/2 and c-Myc survival signals were decreased by (>30%) in HCT116, HT-29, and Caco-2 cells treated with 4 mM butyrate. Conversely, butyrate displayed a stronger potential (>1-fold) for inducing apoptosis and nuclear p21 tumor suppressor in HCT116 cells compared to HT-29 and Caco-2 cells. Moreover, survival analysis demonstrated that a cohort with high p21 gene expression in their colon tissue significantly increased survival time compared to a low-p21-expression cohort of colon cancer patients. Collectively, the inhibitory efficacy of butyrate is cell type-specific and apoptosis-dependent.

Ginsenoside Rg1 promotes β‑amyloid peptide degradation through inhibition of the ERK/PPARγ phosphorylation pathway in an Alzheimer's disease neuronal model

β-Amyloid peptide (Aβ) deposition in the brain is an important pathological change in Alzheimer's disease (AD). Insulin-degrading enzyme (IDE), which is regulated transcriptionally by peroxisome proliferator-activated receptor γ (PPARγ), is able to proteolyze Aβ. One of the members of the MAPK family, ERK, is able to mediate the phosphorylation of PPARγ at Ser112, thereby inhibiting its transcriptional activity. Ginsenoside Rg1 is one of the active ingredients in the natural medicine ginseng and has inhibitory effects on Aβ production. The present study was designed to investigate whether ginsenoside Rg1 is able to affect the regulation of PPARγ based on the expression of its target gene, IDE, and whether it is able to promote Aβ degradation via inhibition of the ERK/PPARγ phosphorylation pathway. In the present study, primary cultured rat hippocampal neurons were treated with Aβ1-42, ginsenoside Rg1 and the ERK inhibitor PD98059, and subsequently TUNEL staining was used to detect the level of neuronal apoptosis. ELISA was subsequently employed to detect the intra- and extracellular Aβ1-42 levels, immunofluorescence staining and western blotting were used to detect the translocation of ERK from the cytoplasm to the nucleus, immunofluorescence double staining was used to detect the co-expression of ERK and PPARγ, and finally, western blotting was used to detect the phosphorylation of PPARγ at Ser112 and IDE expression. The results demonstrated that ginsenoside Rg1 or PD98059 were able to inhibit primary cultured hippocampal neuron apoptosis induced by Aβ1-42 treatment, reduce the levels of intra- and extraneuronal Aβ1-42 and inhibit the translocation of ERK from the cytoplasm to the nucleus. Furthermore, administration of ginsenoside Rg1 or PD98059 resulted in attenuated co-expression of ERK and PPARγ, inhibition of phosphorylation of PPARγ at Ser112 mediated by ERK and an increase in IDE expression. In addition, the effects when PD98059 to inhibit ERK followed by treatment with ginsenoside Rg1 were found to be more pronounced than those when using PD98059 alone. In conclusion, ginsenoside Rg1 was demonstrated to exert neuroprotective effects on AD via inhibition of the ERK/PPARγ phosphorylation pathway, which led to an increase in IDE expression, the promotion of Aβ degradation and the decrease of neuronal apoptosis. These results could provide a theoretical basis for the clinical application of ginsenoside Rg1 in AD.

A Comprehensive Review of Small Interfering RNAs (siRNAs): Mechanism, Therapeutic Targets, and Delivery Strategies for Cancer Therapy

Small interfering RNA (siRNA) delivery by nanocarriers has been identified as a promising strategy in the study and treatment of cancer. Short nucleotide sequences are synthesized exogenously to create siRNA, which triggers RNA interference (RNAi) in cells and silences target gene expression in a sequence-specific way. As a nucleic acid-based medicine that has gained popularity recently, siRNA exhibits novel potential for the treatment of cancer. However, there are still many obstacles to overcome before clinical siRNA delivery devices can be developed. In this review, we discuss prospective targets for siRNA drug design, explain siRNA drug properties and benefits, and give an overview of the current clinical siRNA therapeutics for the treatment of cancer. Additionally, we introduce the siRNA chemical modifications and delivery systems that are clinically sophisticated and classify bioresponsive materials for siRNA release in a methodical manner. This review will serve as a reference for researchers in developing more precise and efficient targeted delivery systems, promoting ongoing advances in clinical applications.

HBV precore G1896A mutation promotes growth of hepatocellular carcinoma cells by activating ERK/MAPK pathway

Chronic hepatitis B virus (HBV) infection is one of the leading causes of hepatocellular carcinoma (HCC). The HBV genome is prone to mutate and several variants are closely related to the malignant transformation of liver disease. G1896A mutation (G to A mutation at nucleotide 1896) is one of the most frequently observed mutations in the precore region of HBV, which prevents HBeAg expression and is strongly associated with HCC. However, the mechanisms by which this mutation causes HCC are unclear. Here, we explored the function and molecular mechanisms of the G1896A mutation during HBV-associated HCC. G1896A mutation remarkably enhanced the HBV replication in vitro. Moreover, it increased tumor formation and inhibited apoptosis of hepatoma cells, and decreased the sensitivity of HCC to sorafenib. Mechanistically, the G1896A mutation could activate ERK/MAPK pathway to enhanced sorafenib resistance in HCC cells and augmented cell survival and growth. Collectively, our study demonstrates for the first time that the G1896A mutation has a dual regulatory role in exacerbating HCC severity and sheds some light on the treatment of G1896A mutation-associated HCC patients.

The Triple Crown: NO, CO, and H2S in cancer cell biology

Nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) are three endogenously produced gases with important functions in the vasculature, immune defense, and inflammation. It is increasingly apparent that, far from working in isolation, these three exert many effects by modulating each other's activity. Each gas is produced by three enzymes, which have some tissue specificities and can also be non-enzymatically produced by redox reactions of various substrates. Both NO and CO share similar properties, such as activating soluble guanylate cyclase (sGC) to increase cyclic guanosine monophosphate (cGMP) levels. At the same time, H2S both inhibits phosphodiesterase 5A (PDE5A), an enzyme that metabolizes sGC and exerts redox regulation on sGC. The role of NO, CO, and H2S in the setting of cancer has been quite perplexing, as there is evidence for both tumor-promoting and pro-inflammatory effects and anti-tumor and anti-inflammatory activities. Each gasotransmitter has been found to have dual effects on different aspects of cancer biology, including cancer cell proliferation and apoptosis, invasion and metastasis, angiogenesis, and immunomodulation. These seemingly contradictory actions may relate to each gas having a dual effect dependent on its local flux. In this review, we discuss the major roles of NO, CO, and H2S in the context of cancer, with an effort to highlight the dual nature of each gas in different events occurring during cancer progression.