Cantharidin-induced liver injuries in mice and the protective effect of vitamin C supplementation

Network toxicology, molecular docking technology, and experimental verification revealed the mechanism of cantharidin-induced testicular injury in mice

As a protein kinase inhibitor, cantharidin (CTD) exhibits antitumor activities. However, CTD is highly toxic, thereby limiting clinical applications. Moreover, relatively few studies have investigated CTD-induced reproductive toxicity, thus the underlying mechanism remains unclear. In this study, the toxic effects of CTD on mouse testis were confirmed in vivo and the potential mechanism was predicted by network toxicology (NT) and molecular docking technology. Proteins involved in the signaling pathways and core targets were verified. The results showed that different concentrations of CTD induced weight loss increased the testicular coefficient, and caused obvious pathological damage to testicular cells. The NT results showed that the main targets of CTD-induced testicular injury (TI) included AKT1, Caspase 3, Bcl-2, and Bax. The results of pathway enrichment analysis showed that CTD-induced TI was closely related to apoptosis and the PI3K/AKT and HIF-1 signaling pathways. Molecular docking methods confirmed high affinity between CTD and key targets. Western blot analysis showed that CTD inhibited expression of PI3K, AKT, and the anti-apoptotic protein Bcl-2, while promoting expression of the pro-apoptotic proteins Bax and Caspase 3. These results suggest that CTD-induced TI involves multiple targets and pathways, and the underlying mechanism was associated with inhibition of the apoptosis-related PI3K/AKT signaling pathway.

Shuganning Injection Suppresses Apoptosis for Protecting Against Cantharidin-Induced Liver Injury by Network Pharmacology and Experiment Validation

Cantharidin (CTD) is a compound of mylabris with antitumor activity, and CTD can potentially cause toxicity, especially hepatotoxicity. The classical Traditional Chinese Medicine prescription Shuganning injection (SGNI) exerts notable anti-inflammatory and hepatoprotective effects. However, the protective property and mechanism of SGNI against CTD-induced liver injury (CTD-DILI) have not yet been elucidated. To investigate the effective compounds, potential targets, and molecular mechanism of SGNI against CTD-DILI, network pharmacology combined with experiments were performed. This study found that SGNI could act with 62 core therapeutic targets, regulate multiple biological processes such as apoptosis, and oxidative stress, and influence apoptotic and p53 signaling pathways to treat CTD-DILI. Subsequently, HepaRG cell experiments demonstrated that SGNI pretreatment significantly increased the levels of GSH-Px and SOD, inhibiting the apoptosis induced by CTD. In vivo, according to H&E staining, SGNI can reduce the degeneration of hepatocytes and cytoplasmic vacuolation in mice exposed to CTD. Western blot analysis results indicated that SGNI pretreatment significantly suppressed the expressions of Caspase-3 and Bax while increasing the expression of Bcl-2. In conclusion, SGNI acted as a protective agent against CTD-DILI by inhibiting apoptosis.

Bibliometric Analysis and Systemic Review of Cantharidin Research Worldwide

BACKGROUND

Cantharidin (CTD), a natural toxic compound from blister beetle Mylabris, has been used for cancer treatment for millenary. CTD and its analogs have become mainstream adjuvant drugs with radiotherapy and chemotherapy in clinical applications. However, the detailed pharmacology mechanism of CTD was not fully elucidated.

METHODS

Publications of CTD were collected from the Web of Science Core Collection database from 1991 to 2023 using CiteSpace, VOSviewer, and Scimago Graphica software.

RESULTS

A total of 1,611 publications of CTD were mainly published in China and the United States. The University of Newcastle has published the most researches. Mcclusey, Adam, Sakoff, Jennette, and Zhang, Yalin had the most CTD publications with higher H. Notably, CTD researches were mainly published in Bioorganic & Medicinal Chemistry Letters and the Journal of Biological Chemistry. Cluster profile results revealed that protein phosphatase 2A (PP2A), human gallbladder carcinoma, Aidi injection, and cell apoptosis were the hotspots. Concentration on the pharmacology function of PP2A subunit regulation, hepatotoxicity, nephrotoxicity, and cardiotoxicity mechanism should be strengthened in the future.

CONCLUSION

Bibliometric analysis combined with a systemic review of CTD research first revealed that PP2A and CTD analogs were the knowledge base of CTD, and PP2A subunit regulation and toxic mechanism could be the frontiers of CTD.

Inflammation and cardiometabolic diseases induced by persistent organic pollutants and nutritional interventions: Effects of multi-organ interactions

The development and outcome of inflammatory diseases are associated with genetic and lifestyle factors, which include chemical and nonchemical stressors. Persistent organic pollutants (POPs) are major groups of chemical stressors. For example, dioxin-like polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFASs), and polybrominated diphenyl ethers (PBDEs) are closely associated with the incidence of inflammatory diseases. The pathology of environmental chemical-mediated inflammatory diseases is complex and may involve disturbances in multiple organs, including the gut, liver, brain, vascular tissues, and immune systems. Recent studies suggested that diet-derived nutrients (e.g., phytochemicals, vitamins, unsaturated fatty acids, dietary fibers) could modulate environmental insults and affect disease development, progression, and outcome. In this article, mechanisms of environmental pollutant-induced inflammation and cardiometabolic diseases are reviewed, focusing on multi-organ interplays and highlighting recent advances in nutritional strategies to improve the outcome of cardiometabolic diseases associated with environmental exposures. In addition, advanced system biology approaches are discussed, which present unique opportunities to unveil the complex interactions among multiple organs and to fuel the development of precision intervention strategies in exposed individuals.

Deciphering the toxicity-effect relationship and action patterns of traditional Chinese medicines from a smart data perspective: a comprehensive review

In Chinese medicine, the primary considerations revolve around toxicity and effect. The clinical goal is to achieve maximize effect while minimizing toxicity. Nevertheless, both clinical and experimental research has revealed a distinct relationship between these two patterns of action in toxic Traditional Chinese Medicines (TCM). These TCM often exhibit characteristic "double-sided" or "multi-faceted" features under varying pathological conditions, transitioning between effective and toxic roles. This complexity adds a layer of challenge to unraveling the ultimate objectives of Traditional Chinese medicine. To address this complexity, various hypotheses have been proposed to explain the toxicity and effect of Traditional Chinese Medicines. These hypotheses encompass the magic shrapnel theory for effect, the adverse outcome pathway framework, and the indirect toxic theory for toxicity. This review primarily focuses on high-, medium-, and low-toxicity Traditional Chinese Medicines as listed in Chinese Pharmacopoeia. It aims to elucidate the essential intrinsic mechanisms and elements contributing to their toxicity and effectiveness. The critical factors influencing the mechanisms of toxicity and effect are the optimal dosage and duration of TCM administration. However, unraveling the toxic-effect relationships in TCM presents a formidable challenge due to its multi-target and multi-pathway mechanisms of action. We propose the integration of multi-omics technology to comprehensively analyze the fundamental metabolites, mechanisms of action, and toxic effects of TCM. This comprehensive approach can provide valuable insights into the intricate relationship between the effect and toxicity of these TCM.

Hepatotoxic mechanism of cantharidin: insights and strategies for therapeutic intervention

Cantharidin (CTD), a natural compound derived from Mylabris, is widely used in traditional Oriental medicine for its potent anticancer properties. However, its clinical application is restricted due to its high toxicity, particularly towards the liver. This review provides a concise understanding of the hepatotoxic mechanisms of CTD and highlights novel therapeutic strategies to mitigate its toxicity while enhancing its anticancer efficacy. We systematically explore the molecular mechanisms underlying CTD-induced hepatotoxicity, focusing on the involvement of apoptotic and autophagic processes in hepatocyte injury. We further discuss the endogenous and exogenous pathways implicated in CTD-induced liver damage and potential therapeutic targets. This review also summarizes the structural modifications of CTD derivatives and their impact on anticancer activity. Additionally, we delve into the advancements in nanoparticle-based drug delivery systems that hold promise in overcoming the limitations of CTD derivatives. By offering valuable insights into the hepatotoxic mechanisms of CTD and outlining potential avenues for future research, this review contributes to the ongoing efforts to develop safer and more effective CTD-based therapies.

The protective effects of vitamins A, C, and E on zinc oxide nanoparticles (ZnO NPs)-induced liver oxidative stress in male Wistar rats

The ever-increasing use of zinc oxide nanoparticles (ZnO NPs) in industrial and consumer products leads to concerns about their safety. Liver is one of the most important target organs of nanoparticles after entering the body. As such, the aim of this study was to evaluate the protective effects of vitamins (Vit) A, C, and E on ZnO NPs-induced liver oxidative stress. For this task, 54 male Wistar rats were randomly divided into nine groups of six: control 1 (water), control 2 (olive oil), Vit A (1000 IU/kg), Vit C (200 mg/kg), Vit E (100 IU/kg), ZnO (200 mg/kg), ZnO + VitA, ZnO + VitC, and ZnO + VitE. The animals received ZnO for 2 weeks while treatment with Vit started one week before the ZnO administration. In order to specify oxidative stress status, total antioxidant capacity (TAC), total oxidative status and malondialdehyde were determined by colorimetric assay. In addition, the activity and gene expression of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were evaluated by colorimetric assay kit and qRT-PCR, respectively. Moreover, histological analysis was conducted to estimate the extent of liver damage. Our results indicate that the oxidative parameters are increased while the content of TAC, antioxidant enzymes activity, and gene expression of SOD, GPX, and CAT show a significant reduction in the liver of ZnO-treated rats compared to the control (p< 0.05). In contrast, the administration of Vit could significantly modulate the aforementioned changes. Overall, Vit A, E, and C can mitigate oxidative stress caused by ZnO NPs.

Mice kidney biometabolic process analysis after cantharidin exposure using widely-targeted metabolomics combined with network pharmacology

Cantharidin (CTD) is a principal bioactive component of traditional Chinese medicine Mylabris used in cancer treatment. However, CTD clinical application is limited due to nephrotoxicity, and the mechanism is unknown. The present study used widely-targeted metabolomics, network pharmacology, and cell experiments to investigate the nephrotoxicity mechanism after CTD exposure. In mice exposed to CTD, serum creatinine and urea nitrogen levels increased with renal injury. Then, 74 differential metabolites were detected, including 51 up-regulated and 23 down-regulated metabolites classified as amino acids, small peptides, fatty acyl, arachidonic acid metabolite, organic acid, and nucleotides. Sixteen metabolic pathways including tyrosine, sulfur, and pyrimidine metabolism were all disrupted in the kidney. Furthermore, network pharmacology revealed that 258 metabolic targets, and pathway enrichment indicated that CTD could activate oxidative phosphorylation and oxidative stress (OS). Subsequently, HK-2 cell experiments demonstrated that CTD could reduce superoxide dismutase while increasing malondialdehyde levels. In conclusion, after CTD exposure, biometabolic processes may be disrupted with renal injury in mice, resulting in oxidative phosphorylation and OS.

Hepatotoxicity of cantharidin is associated with the altered bile acid metabolism

Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague-Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite-gene-enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity.

Protective mechanism of Astragalus Polysaccharides against Cantharidin-induced liver injury determined in vivo by liquid chromatography/mass spectrometry metabolomics

Cantharidin (CTD) is a promising anticancer drug; however, its dosage is limited by hepatotoxicity. We previously showed that Astragalus polysaccharides (APS) effectively improved chemical liver injury. In this study, we established a CTD-induced subacute liver injury mouse model and examined the effects of APS on weight, liver indexes, histopathology, serum biochemical indexes and liver metabolism. Compared with the control group, mice in the CTD model group had obvious liver damage, which was partially prevented by APS. Metabolomics demonstrated that CTD caused liver damage mainly by regulating glycerophospholipid metabolism, ABC transporter pathways and choline metabolism in cancer in vivo. APS regulated primary bile acid biosynthesis and glycerophospholipid metabolism, thus decreasing the liver damage caused by CTD. This study revealed the protective mechanism of APS against CTD-induced liver injury from the perspective of metabolomics. The results provide an important basis for analysing the mechanism of CTD-induced liver toxicity and for assessing clinical treatment options to reduce CTD liver toxicity.

The protective effect of L-glutamine against acute Cantharidin-induced Cardiotoxicity in the mice

Background

Cantharidin (CTD) is a compound which have the potential to be exploited as an antitumor drug, and it has been demonstrated antitumor effects in a variety of cancers. However, the use is limited due to its severe toxicity. It has reported that it can induce fatal cardiac arrhythmias. Fortunately, we found that L-glutamine can alleviate cardiac toxicity caused by cantharidin in mice.

Methods

To investigate the protective effect of L-glutamine, we used a high dose of cantharidin in mice to create a model of cardiotoxicity. In the experimental mice, glutamine was given orally half an hour before they were administrated with cantharidin. The mice of control group were intraperitoneally injected with DMSO solution. The general state of all mice, cardiac mass index, electrocardiogram change and biological markers were determined. Hematoxylin-eosin staining (HE staining) of heart tissue was carried out in each group to reflect the protective effect of glutamine. To investigate the mechanisms underlying the injury and cardio-protection, multiple oxidative stress indexes were determined and succinate dehydrogenase activity was evaluated.

Result

The results showed that L-glutamine (Gln) pretreatment reduced weight loss and mortality. It also decreased the biological markers (p < 0.05), improved electrocardiogram and histological changes that CTD induced cardiotoxicity in mice. Subsequently, the group pretreated with L-glutamine before CTD treatment increases in MDA but decreases in SOD and GSH, in comparison to the group treated with CTD alone. Besides, succinate dehydrogenase activity also was improved when L-glutamine was administrated before cantharidin compared to cantharidin.

Conclusions

This study provided evidence that L-glutamine could protect cardiac cells against the acute cantharidin-induced cardiotoxicity and the protective mechanism of glutamine may be related to the myocardial cell membrane or the tricarboxylic acid cycle in the mitochondria.

Hepatoxicity mechanism of cantharidin-induced liver LO2 cells by LC-MS metabolomics combined traditional approaches

Hepatotoxicity induced by Mylabris has been reported in both clinical and animal experiments. Cantharidin (CTD), the main active compound of Mylabris was responsible for the hepatotoxicity, which aroused widespread concern. However, the mechanism of CTD hepatotoxicity remained unclear. In this study, LO2 cells were exposed to two doses of CTD (6.25 and 25 μM) for 12 h, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were measured. The metabolites in LO2 cells were profiled by LC-MS. Partial least squares discriminant analysis and orthogonal partial least squares discriminant analysis were used for screening potential biomarkers. The MetPA software was used for clustering and pathway analysis. Network pharmacology was used to predict the genes acted with potential biomarkers. Compared with the control group, the levels of ALT, AST, and LDH was significantly increased after CTD treatment. A total of 46 potential biomarkers for hepatotoxicity induced by CTD were identified. And downregulated potential biomarkers reflected the inhibitory effects of CTD toxicity on metabolism of LO2. Moreover, CTD-induced liver toxicity of LO2 cells is mainly related to three pathways: cysteine and methionine metabolism; glutathione metabolism; and glycine, serine, and threonine metabolism. Furtherly, the mRNA expression of CES2, DNMT1, NOS1, NOS3, S1PR2, and CES1 screened by network pharmacology were regulated by CTD. These studies provide valuable mechanistic insights into CTD-associated hepatotoxicity that will aid in the development of therapeutic prevention and treatment options for this liver disease.

Study on the mechanism of cantharidin-induced hepatotoxicity in rat using serum and liver metabolomics combined with conventional pathology methods

Cantharidin (CTD), a compound secreted from Mylabris species, exhibits strong antitumor properties; however, hepatotoxicity restricts its clinical application. The mechanism by which CTD induces toxicity remains unclear. In the present study, the hepatotoxicity of CTD in the rat was investigated using a metabolomic approach combined with conventional pathology methods. A total of 30 rats were intragastrically treated with two doses of CTD (0.75 and 1.5 mg/kg) for 15 days to evaluate hepatotoxicity. Serum and liver samples were collected for biochemical dynamics analyses, histopathological examination and metabolomic analysis. It was found that liver index and serum biochemical indices were significantly increased. Furthermore, the pathology results showed that hepatocytes and subcellular organelles were damaged. Metabolomics analysis found 4 biomarkers in serum and 15 in the liver that were associated with CTD-induced hepatotoxicity. In addition, these were responsible for CTD hepatotoxicity by glycerophospholipid metabolism, sphingolipid metabolism, and steroid hormone biosynthesis. In conclusion, conventional pathology and metabolomics for exploring hepatotoxicity can provide useful information about the safety and potential risks of CTD.

A comprehensive mechanistic review insight into the effects of micronutrients on toll-like receptors functions

Toll-like receptors (TLRs) are the special proteins receptors for recognition of molecules related to the pathogens. In this way, TLRs and secreted cytokines as a result of TLRs activation are involved in the inflammation pathways. So far, in vivo and in vitro studies have demonstrated that micronutrients (vitamins & minerals) with a broad range of effects on body health, can regulate TLRs signaling pathways. Current review aimed at determining the possible mechanisms of micronutrient effects on TLRs functions. In the aspect of gene expression, micronutrients have inconsistent effects on mRNA level of TLRs which are dependent on time, dose and type of studied TLR. Also, some micronutrients affect gene expression of TLRs signaling mediators namely TLRs adaptors like Myeloid differentiation primary response 88 (MyD88). In the aspect of TLRs signaling pathways, nuclear factor-κB (NF-κB) is an important mediator which is regulated by micronutrients. Also, the regulatory effects of micronutrients on phosphorylation reactions may be effective in the activation/inactivation of TLRs signaling mediators. In addition, zinc can regulate TLRs signaling indirectly via the zinc finger proteins which have contradictory effects on TLRs cascade. In conclusion, the relationship between micronutrients and TLRs signaling is complicated and depends on some known internal, external and genetic factors like form of studied micronutrient, cell type, TLR agonist, dose and time of exposure, inflammation, apoptosis, cell cycle, and environmental factors. Some unknown factors may be effective in TLRs response and as a result additional mechanistic studies are needed to elucidate exact effect of micronutrients on TLRs signaling.

UPLC-Q-TOF/MS Based Metabolomics Approach to Study the Hepatotoxicity of Cantharidin on Mice

Cantharidin is the major bioactive compound extracted from the blister beetle, a traditional Chinese medicine, and has been proved to be a natural component with widely antitumor activity. However, clinical application of cantharidin is relatively restricted due to its potential toxic effects, especially hepatotoxicity. Although cantharidin-induced liver injury has been reported, the underlying molecular mechanisms remain unclear. In the present study, an UPLC-Q-TOF/MS based metabolomics approach combined with blood biochemical analysis, histopathological examination, and cell apoptosis assay were used to investigate the mechanisms of cantharidin-induced hepatotoxicity. A total of 54 significantly changed metabolites and 14 disturbed metabolic pathways were identified in the cantharidin exposed groups. Among them, four metabolites (oxidized glutathione, glutathione, 3-sulfinoalanine, and deoxycholic acid 3-glucuronide) were selected based on their high impact value and potential biological function in the process of liver injury post cantharidin treatment. Our study provides a deeper understanding of the mechanisms of cantharidin-induced hepatotoxicity and may contribute to reduce the liver injury and gain more effective and safe clinical use of cantharidin. In addition, our results also demonstrated that cantharidin could impair multiple biological processes in liver, and future studies will be necessary to reveal the detailed molecular mechanisms of cantharidin-induced hepatotoxicity.

Hepatoprotective benefits of vitamin C against perfluorooctane sulfonate-induced liver damage in mice through suppressing inflammatory reaction and ER stress

Our previous studies show that vitamin C (VC) plays promising hepatoprotection in mice. Intrahepatic exposure of perfluorooctane sulfonate (PFOS) can induce dose-dependent cytotoxicity. However, pharmacology-based assessment of VC on PFOS remains uninvestigated. This study aimed to evaluate the therapeutic benefits of VC on inhibiting PFOS-induced liver steatosis in mice, followed by representative biochemical analysis and immunoassay. As results, VC was beneficial for reduced PFOS-induced liver damages, as showed in reductions of serological levels of transaminases (ALT and AST), lipids (TG and TC), fasting glucose and insulin, inflammatory cytokines (TNF-α and IL6), while content of fibroblast growth factor 21 (FGF21) in serum was increased. In addition, VC reduced histiocytic changes of PFOS-lesioned livers, as revealed in reduced TNF-α-labeled cells and increased FGF21-labeled cells in immunofluorescence assay. Further, intrahepatic expressions of endoplasmic reticulum (ER) stress-based ATF6, eIF2α, GRP78, XBP1 proteins were down-regulated by treatments of VC. Taken together, our preliminary findings set forth that VC exerts pharmacological benefits against PFOS-induced liver steatosis in mice, and the underlying biological mechanism may be linked to suppressing hepatocellular inflammatory reaction and ER stress.

Establishment and Validation of an In Vitro Screening Method for Traditional Chinese Medicine-Induced Nephrotoxicity

Renal injury is among the adverse drug reactions (ADRs) caused by herbal medicine products (HMPs). Traditional Chinese medicines (TCMs) have been practiced for over 2000 years in China and East Asia, and herbs are currently used worldwide for the treatment and prevention of chronic and acute disease. Operetta high content analysis (HCA, PerkinElmer, Waltham, MA, USA), which is an in vitro, sensitive, reproducible, multiparametric screening method, was used to evaluate the cytotoxicity of HMPs in cultures of HEK293 human embryo kidney cells. Cytotoxic results were validated by an animal-based subacute toxicity assay. The renal safety of 18 active pharmaceutical agents from 13 TCM herbs with known nephrotoxic potential was evaluated in HEK293 human embryonic kidney cells. A panel of five parameters, cell viability, nuclear area, nuclear roundness, mitochondrial mass, and mitochondrial membrane potential, was utilized to evaluate drug-induced renal mitochondrial and nuclear injury. HCA can be a useful tool for preclinical screening and postclinical evaluation of HMPs. The nephrotoxicity of diosbulbin B and other HMPs was evident at a concentration as low as 0.01 μM.

Cancer Chemotherapy Specific to Acidic Nests

The realization of cancer therapeutics specific to cancer cells with less of an effect on normal tissues is our goal. Many trials have been carried out for this purpose, but this goal is still far from being realized. It was found more than 80 years ago that solid cancer nests are acidified, but in vitro studies under acidic conditions have not been extensively studied. Recently, in vitro experiments under acidic conditions were started and anti-cancer drugs specific to acidic areas have been identified. Many genes have been reported to be expressed at a high level under acidic conditions, and such genes may be potent targets for anti-cancer drugs specific to acidic nests. In this review article, recent in vitro, in vivo, and clinical achievements in anti-cancer drugs with marked efficacy under acidic conditions are summarized, and the clinical use of anti-cancer drugs specific to acidic nests is discussed.

Cantharis by photosynthetic bacteria biotransformation: Reduced toxicity and improved antitumor efficacy

ETHNOPHARMACOLOGICAL RELEVANCE

The blister beetle, also known as Mylabris cichorii, is not only widely used in clinical applications in Chinese anticancer medicine, but is also one of the main ingredients in a variety of traditional Chinese medicinal preparations with anticancer activity. However, the strong toxicity exhibited by this beetle species limits its clinical applicability, with the photosynthetic bacteria featuring a strong biological conversion function. Therefore, in this study we explore the use of photosynthetic bacteria for bioconversion of the blister beetle in order to reduce the toxicity and in effort to enhance the overall antitumor effect.

METHODS AND RESULTS

In the first set of experiments, we utilized an orthogonal experimental design to optimize the culture medium of photosynthetic bacteria. Concurrently, the growth curve of photosynthetic bacteria was used to determine the inoculation amount of the photosynthetic bacteria and the safe concentration of cantharis. Through antitumor activity experiments conducted in vitro we found that the inhibition rate increased through cantharis by PSB biotransformation of HepG2, A549 and BEL-7406 cells. Furthermore, through acute toxicity tests in mice it was found that the blister beetle water extraction liquid exhibits a LD50 value of 1383mg/kg, while the blister beetle transformation liquid exhibits a LD50 value of 206mg/kg. The LD50 value of the blister beetle water extract was found to be 6.7 times higher than the transformation liquid, thus demonstrating that the toxicity of cantharis by PSB biotransformation may be decreased. More strikingly, decreased toxicity was observed in the mouse liver and in pathological sections of the kidneys after transformation.

CONCLUSIONS

In this paper we demonstrate for the first time that PSB bioconversion of the blister beetle is able to reduce the toxicity of a common method used in anticancer treatments as part of the principles in traditional Chinese medicine and may therefore improve antitumor activity in vitro.