Realgar bioleaching solution is a less toxic arsenic agent in suppressing the Ras/MAPK pathway in Caenorhabditis elegans

Uncovering the Molecular Pathways Implicated in the Anti-Cancer Activity of the Imidazoquinoxaline Derivative EAPB02303 Using a Caenorhabditis elegans Model

Imiqualines are analogues of the immunomodulatory drug imiquimod. EAPB02303, the lead of the second-generation imiqualines, is characterized by significant anti-tumor effects with IC50s in the nanomolar range. We used Caenorhabditis elegans transgenic and mutant strains of two key signaling pathways (PI3K-Akt and Ras-MAPK) disrupted in human cancers to investigate the mode of action of EAPB02303. The ability of this imiqualine to inhibit the insulin/IGF1 signaling (IIS) pathway via the PI3K-Akt kinase cascade was explored through assessing the lifespan of wild-type worms. Micromolar doses of EAPB02303 significantly enhanced longevity of N2 strain and led to the nuclear translocation and subsequent activation of transcription factor DAF-16, the only forkhead box transcription factor class O (Fox O) homolog in C. elegans. Moreover, EAPB02303 significantly reduced the multivulva phenotype in let-60/Ras mutant strains MT2124 and MT4698, indicative of its mode of action through the Ras pathway. In summary, we showed that EAPB02303 potently reduced the activity of IIS and Ras-MAPK signaling in C. elegans. Our results revealed the mechanism of action of EAPB02303 against human cancers associated with hyperactivated IIS pathway and oncogenic Ras mutations.

Recent advances in the potential effects of natural products from traditional Chinese medicine against respiratory diseases targeting ferroptosis

Respiratory diseases, marked by structural changes in the airways and lung tissues, can lead to reduced respiratory function and, in severe cases, respiratory failure. The side effects of current treatments, such as hormone therapy, drugs, and radiotherapy, highlight the need for new therapeutic strategies. Traditional Chinese Medicine (TCM) offers a promising alternative, leveraging its ability to target multiple pathways and mechanisms. Active compounds from Chinese herbs and other natural sources exhibit anti-inflammatory, antioxidant, antitumor, and immunomodulatory effects, making them valuable in preventing and treating respiratory conditions. Ferroptosis, a unique form of programmed cell death (PCD) distinct from apoptosis, necrosis, and others, has emerged as a key area of interest. However, comprehensive reviews on how natural products influence ferroptosis in respiratory diseases are lacking. This review will explore the therapeutic potential and mechanisms of natural products from TCM in modulating ferroptosis for respiratory diseases like acute lung injury (ALI), asthma, pulmonary fibrosis (PF), chronic obstructive pulmonary disease (COPD), lung ischemia-reperfusion injury (LIRI), pulmonary hypertension (PH), and lung cancer, aiming to provide new insights for research and clinical application in TCM for respiratory health.

Pharmacology, Toxicology, and Rational Application of Cinnabar, Realgar, and Their Formulations

Ethnopharmacological Relevance. Mineral medicines are widely used traditional Chinese medicines with curative effects. These medicines are used for many refractory diseases. Aim of the Review. In this review, cinnabar (HgS) and realgar (As₂S₂) serve as examples of mineral medicines, and their pharmacology, therapeutic toxicity, use in traditional medicine mixtures, and research perspectives are discussed. Materials and Methods. A search was performed for the literature on cinnabar and realgar in PubMed, the Chinese Pharmacopeia, Google, and other sources. The search included studies using single herbs, traditional formulations, or novel dosage forms. Results. Cinnabar and cinnabar formulas exhibit good efficacy for sedation, sleep improvement, anxiety alleviation, and brain protection. However, previous studies on neurotransmitters have reached different conclusions, and detailed pharmacological mechanisms are lacking. Realgar and its formulas exert promising antitumor activity through regulation of cell cycle arrest, intrinsic and extrinsic apoptosis, induction of differentiation, autophagy, metabolic reprogramming, matrix metalloproteinase-9 (MMP-9) signaling, and reactive oxygen species (ROS) generation. In addition, realgar can be used to treat a variety of refractory diseases by regulating immunity and exerting antibacterial, antiviral, and other effects. However, the existing pharmacological research on the use of realgar for epidemic prevention is insufficient, and animal experiments and research at the cellular level are lacking. Inappropriate applications of cinnabar and realgar can cause toxicity, including neurotoxicity, liver toxicity, kidney toxicity, and genotoxicity. The toxicological mechanism is complex, and molecular-level research is limited. For clinical applications, theory and clinical experience must be combined to guide scientific and rational drug use and to achieve reduced toxicity and increased efficacy through the use of modern preparation methods or combined drugs. Notably, when cinnabar and realgar are used to treat targeted diseases, these agents have a bidirectional effect of “treatment” and “toxicity” on the central nervous system in pathological and normal states. The pharmacological and toxicological mechanisms need to be elucidated in greater detail in the future. Overall, systematic research is needed to provide a basis for better promotion of the rational use of cinnabar and realgar in the clinic. Conclusion. Mineral medicines are multicomponent, multiactivity, and multitargeted substances. The pharmacology and mechanisms of the toxicity and action of realgar and cinnabar are extremely complex. A number of Chinese medicinal preparations of realgar and cinnabar have demonstrated unique efficacy in the treatment of refractory diseases.

Realgar increases defenses against infection by Enterococcus faecalis in Caenorhabditis elegans

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar has been used in traditional remedies for a long history in China and India. It is clinically used to treat diverse cancers, especially acute promyelocytic leukemia (APL), chronic myelogenous leukemia (CML) in China. However, paradoxic roles of realgar to increase or decrease immunity are reported. It is urgent to address this question, due to immune depression can be strongly benefit to cancer development, but detrimental to patients.

AIM OF THE STUDY

This present work is to explore whether realgar promote or suppress immune responses, and shed light on its mode of action. Our results should provide cues for rational strategy to explore realgar for clinical use.

MATERIAL AND METHODS

Infection model in vivo was established by using Enterococcus faecalis to attack Caenorhabditis elegans, then realgar was used to treat the infected worms to investigate its effects on infectivity and the underlying mechanism. Killing analysis was carried out to test whether realgar can mitigate worm infection. Thermotolerance resistance analysis was used to evaluate if realgar functions hormetic effect. Quantification of live E. faecalis in nematode intestine was employed to ascertain if realgar alleviate the bacterial load in worm gut. Quantitative real-time PCR (qRT-PCR) was used to test the expression of antibacterial effectors. Western blot was used to test the effect of realgar on the expressions of p38 and phospho-p38 in worms infected by E. faecalis.

RESULTS

Realgar alleviated the infected worms in strains of N2, glp-4, and daf-2, but failed in sek-1, glp-4; sek-1, and daf-2; daf-16 when p38 MAPK or daf-16 was blocked or inactivated. Western blot assay demonstrated that realgar increased the expression of phosph-p38. Thermotolerance assay showed that realgar played a hormetic role on nemtodes, triggered protective response and reduced bacterial load after realgar treatment for 120 h qRT-PCR demonstrated that realgar significantly increased antibacterial effectors, thus leading to pathogen elimination.

CONCLUSION

Realgar increased defenses against E. faecalis in C. elegans by inducing both immune responses and protective responses. It was regulated by p38 MAPK pathway and DAF-16.

Grape seed proanthocyanidin extract alleviates arsenic-induced lung damage through NF-κB signaling

IMPACT STATEMENT

Arsenic-induced respiratory inflammatory damage is an important occupational hazard in many areas of the world, particularly in underdeveloped and developing countries. Effective treatments are lacking and expensive. Therefore, the aim of the study was to examine the anti-inflammatory effects of proanthocyanidin (PC) and the molecular mechanisms in vivo and in vitro. The present study showed that PC extracted from grape seed could attenuate the lung damage in a mouse model of arsenic poisoning. The effects were observed at the level of lung histology and inflammasome expression. This study suggests that a natural compound is effective in mitigating the toxic effects of arsenic in the lungs, providing an inexpensive and more readily accessible method for treating arsenic exposure in some parts of the world.

Target lipidomics approach to reveal the resolution of inflammation induced by Chinese medicine combination in Liu-Shen-Wan against realgar overexposure to rats

ETHNOPHARMACOLOGICAL RELEVANCE

Liu-Shen-Wan (LSW) is one of the popular over-the-counter drugs in Asia, which contains realgar (As₄S₄), used for the treatment of upper respiratory tract inflammation and skin infections. However, the safety and potential risk of this arsenic remain unknown.

AIM OF THE STUDY

The aim of this study was to determine total arsenic in tissue and investigate effects of regular dose and overdose LSW exposure on rat liver.

MATERIALS AND METHODS

We used a target lipidomics approach to quantify inflammatory eicosanoids and employed ICP-MS to determine total arsenic in tissue.

RESULTS

The results showed that oral administration of 8 and 40 mg/kg LSW (1 and 5 fold human-equivalent dose) induced light changes of liver lipidomic profile in rats, which was associated with anti-inflammatory function of LSW. In our recent report, we observed that 41 and 134 mg/kg realgar (40 and 132 fold human-equivalent dose) stimulated rat liver inflammation through up-regulation of pro-inflammatory LOX-derived, CYP-derived HETEs and COX-derived PGs. However, we found that LSW in the form of drug combination, containing 41 and 134 mg/kg realger, could not stimulate these similar inflammatory responses in rats, although the liver total arsenic levels of the realger and LSW groups were same.

CONCLUSION

The downregulation of pro-inflammatory response showed that the LSW containing realger is safer than realger alone administrated to rats. These results suggested that Chinese medicines combination could reduce realgar-derived arsenic toxicity in rats.

Arsenic Disulfide Combined with L-Buthionine-(S, R)-Sulfoximine Induces Synergistic Antitumor Effects in Two-Dimensional and Three-Dimensional Models of MCF-7 Breast Carcinoma Cells

Three-dimensionally (3D) cultured tumor cells (spheroids) exhibit more resistance to therapeutic agents than the cells cultured in traditional two-dimensional (2D) system (monolayers). We previously demonstrated that arsenic disulfide (As₂S2) exerted significant anticancer efficacies in both 2D- and 3D-cultured MCF-7 cells, whereas 3D spheroids were shown to be resistant to the As₂S₂ treatment. L-buthionine-(S, R)-sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, has been regarded to be a potent candidate for combinatorial treatment due to its GSH modulation function. In the present study, we introduced BSO in combination with As₂S₂ at a low concentration to investigate the possible enhancing anticancer efficacy by the combinatorial treatment on 2D- and 3D-cultured MCF-7 cells. Our results presented for the first time that the combination of As₂S₂ and BSO exerted potent anticancer synergism in both MCF-7 monolayers and spheroids. The IC50 values of As₂S₂ in combinatorial treatment were significantly lower than those in treatment of As₂S₂ alone in both 2D- and 3D-cultured MCF-7 cells (P<0.01, respectively). In addition, augmented induction of apoptosis and enhanced cell cycle arrest along with the regulation of apoptosis- and cell cycle-related proteins, as well as synergistic inhibitions of PI3K/Akt signals, were also observed following co-treatment of As₂S₂ and BSO. Notably, the combinatorial treatment significantly decreased the cellular GSH levels in both 2D- and 3D-cultured MCF-7 cells in comparison with each agent alone (P<0.05 in each). Our results suggest that the combinatorial treatment with As₂S₂ and BSO could be a promising novel strategy to reverse arsenic resistance in human breast cancer.

Lipidomic profiling of subchronic As4S4exposure identifies inflammatory mediators as sensitive biomarkers in rats

Arsenic sulfide compounds provide nearly all of the world's supply of arsenic.

Kushui Rose (R. Setate x R. Rugosa) decoction exerts antitumor effects in C. elegans by downregulating Ras/MAPK pathway and resisting oxidative stress

Kushui rose (R. Setate x R. Rugosa) (KR) is a traditional Chinese medicine proven to be a potent antioxidant, and used for thousands of years. Approximately 30% of all human cancers relevant to mutational activated Ras, and over-activated Ras are accompanied by increased accumulation of reactive oxygen species (ROS). Thus, one way of developing anticancer drugs is to reduce ROS accumulation. Therefore, KR was predicted to have potential to combat over-activated Ras-related cancer. C. elegans with let‑60(gf)/ras mutant, which exhibited tumor-like symptoms of the multivulva phenotype, was employed to determine the effect of KR on Ras/MAPK pathway. Other strains of worms and H2DCF-DA dye were also applied to study the antioxidant stress capacity of KR. This study was aimed to determine whether KR has a potential effect on combat over-activated Ras-related cancer through resistance to oxidative stress. Our results showed that Kushui rose decoction (KRD) has potent antioxidant activity in vitro, and can inhibit over-activated Ras in vivo. Further, KRD significantly suppressed over-activated Ras/MAPK pathway by regulating oxidative stress-related proteins, such as forkhead transcription factor (DAF-16), glutathione S-transferase-4 (GST-4), superoxide dismutases (SODs) and heat shock protein-16.2 (HSP-16.2). However, essential oil and hydrosol of KR had no effect on over-activated Ras. Thus these results reminded us that people usually soak rose in hot water to prepare 'rose tea' as an effective way for health care. Thus, KRD was demonstrated to be a potential drug candidate for combating over-activated Ras-related cancer as an antioxidant.

Realgar transforming solution suppresses angiogenesis and tumor growth by inhibiting VEGF receptor 2 signaling in vein endothelial cells

Realgar (As₄S₄), as an arsenic sulfide mineral drug, has a good therapeutic reputation for anticancer in Traditional Chinese Medicine, and has recently been reported to inhibit angiogenesis in tumor growth. However, considering the poor solubility and low bioavailability of realgar, large dose of realgar and long period of treatment are necessary for achieving the effective blood medicine concentration. In present study, we resolved the crucial problem of poor solubility of realgar by using intrinsic biotransformation in microorganism, and investigated underlying mechanisms of realgar transforming solution (RTS) for antiangiogenesis. Our results demonstrated that RTS had a strong activity to inhibit HUVECs proliferation, migration, invasion, and tube formation. Moreover, RTS inhibited VEGF/bFGF-induced phosphorylation of VEGFR2 and the downstream protein kinases including ERK, FAK, and Src. In vivo zebrafish and chicken chorioallantoic membrane model experiments showed that RTS remarkably blocked angiogenesis. Finally, compared with the control, administration of 2.50 mg/kg RTS reached more than 50% inhibition against H22 tumor allografts in KM mice, but caused few toxic effects in the host. The antiangiogenic effect was indicated by CD31 immunohistochemical staining and alginate-encapsulated tumor cell assay. In summary, our findings suggest that RTS inhibits angiogenesis and may be a potential drug candidate in anticancer therapy.

Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent

Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.

Shengmai Formula suppressed over-activated Ras/MAPK pathway in C. elegans by opening mitochondrial permeability transition pore via regulating cyclophilin D

Since about 30% of all human cancers contain mutationally activated Ras, down regulating the over-activation of Ras/MAPK pathway represents a viable approach for treating cancers. Over-activation of Ras/MAPK pathway is accompanied by accumulation of reactive oxygen species (ROS). One approach for developing anti-cancer drugs is to target ROS production and their accumulation. To test this idea, we have employed C. elegans of let-60 (gf) mutant, which contain over-activated let-60 (the homolog of mammalian ras) and exhibit tumor-like symptom of multivulva phenotype, to determine whether anti-oxidants can affect their tumor-like phenotype. Specifically we studied the effect of Shengmai formula (SM), a traditional Chinese medicine that has strong anti-oxidant activity, on the physiology of let-60 (gf) mutants. Unexpectedly, we found that SM treatment led to the opening of mitochondrial permeability transition pore by regulating cyclophilin D and then triggered oxidative stress and related signaling pathway activation, including p53, JNK, and p38/MAPK pathways. Finally, SM induced mitochondrial pathway of apoptosis and inhibited the tumor-like symptom of the multivulva phenotype of let-60(gf) mutants. Our results provide evidences to support that SM act as a pro-oxidant agent and could serve as a potential drug candidate for combating over-activated Ras-related cancer.