A novel approach combining network pharmacology and experimental validation to study the protective effect of ginsenoside Rb1 against cantharidin-induced hepatotoxicity in mice

Cantharidin (CTD) is a widely used anticancer compound, but its clinical use is mainly limited due to hepatotoxicity. Ginsenoside Rb1 (GRb1) shows potential hepatoprotective effects. Nonetheless, the protective effect and underlying mechanism of GRb1 against CTD-induced hepatotoxicity in mice have not been investigated. This study aims to elucidate the effect and mechanism of GRb1 on CTD-induced hepatotoxicity using network pharmacology and in vivo experiments. Network pharmacology studies have shown that 263 targets were the main mechanisms by which GRb1 alleviates CTD-induced hepatotoxicity. KEGG enrichment analysis revealed that 75 hub genes were mainly enriched in TNF, IL-17 and apoptosis signalling pathways. Molecular docking analysis showed that GRb1 exhibited high affinity with Akt1, Tnf, Il6, Bcl2 and Caspase3. In addition, results from animal studies demonstrated that GRb1 could ameliorate CTD-induced hepatotoxicity by inhibiting protein expression of Caspase-3, Caspase-8, Bcl-2/Bax, GRP78, ATF6, ATF4, CHOP, IRE1α and PERK. This research revealed the mechanism of GRb1 against CTD-induced hepatotoxicity by inhibiting apoptosis and endoplasmic reticulum stress (ERS) and it may provide a scientific rationale for the potential use of GRb1 in the treatment of hepatotoxicity induced by CTD.

Dissecting the role of mitogen-activated protein kinase Hog1 in yeast flocculation

Living organisms are frequently exposed to multiple biotic and abiotic stress forms during their lifetime. Organisms cope with stress conditions by regulating their gene expression programs. In response to different environmental stress conditions, yeast cells activate different tolerance mechanisms, many of which share common signaling pathways. Flocculation is one of the key mechanisms underlying yeast survival under unfavorable environmental conditions, and the Tup1-Cyc8 corepressor complex is a major regulator of this process. Additionally, yeast cells can utilize different mitogen-activated protein kinase (MAPK) pathways to modulate gene expression during stress conditions. Here, we show that the high osmolarity glycerol (HOG) MAPK pathway is involved in the regulation of yeast flocculation. We observed that the HOG MAPK pathway was constitutively activated in flocculating cells, and found that the interaction between phosphorylated Hog1 and the FLO genes promoter region increased significantly upon sodium chloride exposure. We found that treatment of cells with cantharidin decreased Hog1 phosphorylation, causing a sharp reduction in the expression of FLO genes and the flocculation phenotype. Similarly, deletion of HOG1 in yeast cells reduced flocculation. Altogether, our results suggest a role for HOG MAPK signaling in the regulation of FLO genes and yeast flocculation.

Analysis of cantharidin-induced kidney injury and the protective mechanism of resveratrol in mice determined by liquid chromatography/mass spectrometry-based metabonomics

Cantharidin (CTD) is the main active component in the traditional Chinese medicine Mylabris and an effective anti-tumor agent. However, it is relatively toxic and exhibits nephrotoxicity, which limits its clinical use. However, its toxic mechanism is not clear. The toxic effects of CTD exposure on the kidney and the protective effect of resveratrol (RES) were studied in a mouse model, by determination of serum biochemical and renal antioxidant indicators, histopathological and ultrastructural observation, and metabonomics. After CTD exposure, serum uric acid, creatinine, and tissue oxidative stress indicators increased, and the renal glomerular and tubular epithelial cells showed clear pathological damage. Ultrastructure observation revealed marked mitochondrial swelling, endoplasmic reticulum dilation, and the presence of autophagy lysosomes in glomerular epithelial cells. RES ameliorated the renal injury induced by CTD. Metabonomics analysis indicated that CTD can induce apoptosis and oxidative damage in kidney cells, mainly by disrupting sphingolipid and glutathione metabolism, increasing sphingosine and sphingomyelin levels, and decreasing glutathione levels. RES counteracts these effects by regulating renal cell proliferation, the inflammatory response, oxidative stress, and apoptosis, by improving the levels of phosphatidylcholine (PC), LysoPC, and lysophosphatidyl glycerol in the glycerophospholipid metabolism pathway, thereby reducing CTD-induced nephrotoxicity. The mechanisms of CTD-induced renal injury and the protective effect of RES were revealed by metabonomics, providing a basis for evaluating clinical treatment regimens to reduce CTD-induced nephrotoxicity.

Application of cantharidin, retinoic acid cream and salicylic acidy in multiple palmoplantar warts

OBJECTIVE

Multiple palmoplantar warts, caused by human papillomavirus (HPV) infection, were investigated for clinical efficacy using cantharidin, retinoic acid cream, and salicylic acid cream.

METHODS

A total of 110 patients with multiple palmoplantar warts were enrolled. The experimental group (54 cases) received a 1:1:1 combination (CRS) of 0.25% cantharidin, 0.1% retinoic acid cream, and 5% salicylic acid, applied with pressurized encapsulation for 8 h every night, three times per week. The control group (56 cases) underwent conventional liquid nitrogen freezing. Monthly follow-ups assessed cure rate, effective rate, dermatological life quality index (DLQI), visual analog scale (VAS), and cost, with evaluations conducted after 3 months.

RESULTS

The treatment group exhibited a cure rate of 85.19% and a total effective rate of 96.30%, surpassing the control group with rates of 39.29% and 51.79%, respectively (p < 0.05). The treatment group's DLQI score (1.84 ± 1.06) was significantly lower than the control group's score (6.04 ± 1.78) (p = 0.0005). Additionally, the treatment group's VAS score (1.84 ± 1.06) was notably lower than the control group's score (8.56 ± 1.07) (p < 0.0001). The treatment group's total cost (43.20 ± 2.85) was markedly lower than the control group's cost (206.38 ± 90.81), with a statistically significant difference (p < 0.0001).

CONCLUSION

The combination of cantharidin, retinoic acid cream, and salicylic acid with local encapsulation is a safe, effective, economical, and convenient treatment method for multiple palmoplantar warts, exhibiting few side effects and showing promise.

Cantharidin-Based Verbenone Derivatives as a Novel Insecticide against Plutella xylostella: Design, Synthesis, Insecticidal Activity Evaluation, and 3D QSAR Study

The diamondback moth is a detrimental insect pest of brassicaceous crops which was among the first crop insects to be reported as DDT resistant. It has since proven to be significantly resistant to nearly every synthetic insecticide used in the field in many crucifer-producing regions. Due to insecticide control failures in some parts of the world, economically viable crucifer production is now all but impossible. As a result, there has been an increasing effort to identify new compounds with strong pesticidal activity. Cantharidin is one such compound that has been shown to be highly effective against a variety of insect pests. However, its chemical synthesis and potential toxicity to non-target organisms have been a major source of concern. Herein, using rational design approaches, a new series of cantharidin-based verbenone derivatives were synthesized and evaluated for their insecticidal activities against the diamondback moth. Among different compounds screened, compounds 6a, 6h, 6i, and 6q emerged as the most potent compounds exhibiting 100% mortality at a concentration of 100 mg/L after four days. These compounds demonstrated a good anti-feeding effect against the diamondback moth on cabbage leaves. Subsequently, a 3D QSAR study was carried out to identify the key structural features of the synthesized compounds and their correlation with insecticidal activity.

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.

Comparative efficacy of treatments for molluscum contagiosum: A systematic review and network meta-analysis

BACKGROUND AND OBJECTIVES

Various interventions have been applied to treat molluscum contagiosum, but benefits and efficacy remain unclear. To assess the comparative efficacy and safety of interventions for molluscum contagiosum, a network meta-analysis was performed.

PATIENTS AND METHODS

Embase, PubMed, and the Cochrane Library were searched for articles published between January 1, 1990, and November 31, 2020. Eligible studies were randomized clinical trials (RCTs) of interventions in immunocompetent children and adults with genital/non-genital molluscum contagiosum lesions.

RESULTS

Twelve interventions from 25 RCTs including 2,123 participants were assessed. Compared with the placebo, ingenol mebutate had the most significant effect on complete clearance (odds ratio [OR] 117.42, 95% confidence interval [CI] 6.37-2164.88), followed by cryotherapy (OR 16.81, 95% CI 4.13-68.54), podophyllotoxin (OR 10.24, 95% CI 3.36-31.21), and potassium hydroxide (KOH) (OR 10.02, 95% CI 4.64-21.64). Data on adverse effects were too scarce for quantitative synthesis.

CONCLUSIONS

Ingenol mebutate, cryotherapy, podophyllotoxin, and KOH were more effective than the other interventions in achieving complete clearance, but safety concerns regarding ingenol mebutate have recently been reported. Due to the possibility of spontaneous resolution, observation is also justified for asymptomatic infection. Factors including adverse effects, cost, patient preference, and medical accessibility should be considered.

Quality Evaluation of Traditional Chinese Medicine Mylabris Based on Heavy Metal Risk Assessment and Analysis of Pharmacological Component Contents

As a highly representative traditional Chinese anti-tumor medicinal material, the biomass of Mylabris is collected from the wild. However, the living environments of Mylabris is differ, so Mylabris may be contaminated by heavy metal pollution depending on the environment. These environments may also affect the amount of biosynthesis of its medicinal ingredient, cantharidin, there by affecting the quality of Mylabris. In this study, we determined the heavy metal content in Mylabris from different origins by using ICP-MS, evaluated the risk posed by these heavy metals, and recommended theoretical maximum limits of heavy metals in medicinal Mylabris. The results show that the Cu content in Mylabris is substantially higher than that in Cr, As, Pb, Cd, and Hg. A quantitative risk assessment showed that Mylabris poses no noncarcinogenic risks. The results of the total carcinogenic risk value showed that origins S12 and S13 pose carcinogenic risk by Cr and As, and the rest of the origins were in the human-tolerable carcinogenic risk range. We found large differences in the cantharidin content in Mylabris from different origins. In general, the Mylabris from origins S2, S3 and S4 had a higher in vivo cantharidin content, which proved that the quality of the medicinal materials was higher here than in other production areas. Finally, we providing a reference for the quality evaluation of medicinal Mylabris materials.

Cantharidin and Its Analogue Norcantharidin Inhibit Metastasis-Inducing Genes S100A4 and MACC1

Colorectal cancer (CRC) is the third most prevalent and second deadliest cancer worldwide. In addition, metastasis directly causes up to 90% of all CRC deaths, highlighting the metastatic burden of the disease. Biomarkers such as S100A4 and MACC1 aid in identifying patients with a high risk of metastasis formation. High expression of S100A4 or MACC1 and to a greater extent the combination of both biomarkers is a predictor for metastasis and poor patient survival in CRC. MACC1 is a tumor-initiating and metastasis-promoting oncogene, whereas S100A4 has not been shown to initiate tumor formation but can, nevertheless, promote malignant tumor growth and metastasis formation. Cantharidin is a natural drug extracted from various blister beetle species, and its demethylated analogue norcantharidin has been shown in several studies to have an anti-cancer and anti-metastatic effect in different cancer entities such as CRC, breast cancer, and lung cancer. The impact of the natural compound cantharidin and norcantharidin on S100A4 and MACC1 gene expression, cancer cell migration, motility, and colony formation in vitro was tested. Here, for the first time, we have demonstrated that cantharidin and norcantharidin are transcriptional inhibitors of S100A4 and MACC1 mRNA expression, protein expression, and motility in CRC cells. Our results clearly indicate that cantharidin and, to a lesser extent, its analogue norcantharidin are promising compounds for efficient anti-metastatic therapy targeting the metastasis-inducing genes S100A4 and MACC1 for personalized medicine for cancer patients.

Cantharidin-Podophyllin-Salicylic Acid Formulation as a First-Line Treatment for Plantar Warts? A Case Report with Multiple Plantar Warts of Human Papillomavirus Biotype 27 and Previous Failed Treatments

BACKGROUND Plantar warts are benign skin tumors caused by the human papillomavirus (HPV). There are multiple treatments, but none ensure absolute success. Successful treatment depends on several factors, such as the location, number of lesions, HPV biotype, and the patient's health condition. This report presents a 53-year-old woman who had multiple recalcitrant plantar warts with HPV biotype 27 that were treated using a cantharidin-podophyllin-salicylic acid (CPS) formulation after 2 failed treatments. CASE REPORT A 53-year-old woman was seen on October 25, 2021. She had 6 plantar warts due to HPV biotype 27, which was confirmed by polymerase chain reaction using a sample of hyperkeratosis scales obtained from the wart after debridement. Five cryotherapy sessions were applied, without clinical improvement. Two sessions of nitric-acid-zinc complex were then applied, from which the patient reported severe pain, without clinical improvement. Finally, 3 sessions of CPS formulation were applied, and the HPV remitted in all warts. CONCLUSIONS Conservative treatments, such as cryotherapy, have not been effective in a case of multiple recalcitrant plantar warts. The combined action of the 3 compounds of CPS formulation was key in the resolution of this case. Plantar wart treatment should be easy to apply, effective, fast, and efficient. In cases of recalcitrant or numerous warts, treatment should be more aggressive from the beginning if the patient's lifestyle allows it. It would be interesting to conduct randomized clinical trials to find out which patients could be indicated for the CPS formulation as a first line of treatment.

Therapeutic induction of Bcl2-associated athanogene 3-mediated autophagy in idiopathic pulmonary fibrosis

BACKGROUND

Exaggerated fibroblast proliferation is a well-known feature in idiopathic pulmonary fibrosis (IPF) which may be - in part - due to insufficient autophagy, a lysosome dependent cellular surveillance pathway. Bcl2-associated athanogene 3 (BAG3) is a pivotal co-chaperone of the autophagy pathway. Here, we studied whether therapeutic modulation of BAG3-mediated autophagy can rescue insufficient autophagy and impact IPF fibroblast proliferation.

METHODS

Primary interstitial fibroblasts or precision cut lung slices (PCLS) of IPF lungs were treated with (1) the antifibrotic drug pirfenidone (Pirf), (2) the demethylating agent 5-azacytidine (Aza), (3) the BAG3 modulator cantharidin (Ctd). Autophagy flux was measured following pretreatment with the autophagy inhibitors or by GFP-RFP-LC3B transfection followed by drug treatments. Proliferation was measured by 5-bromo-2'-deoxyuridine assay. BAG3, filamin C (FLNC), proliferating-cell-nuclear-antigen (PCNA), collagen1A1 (COL1A1) and autophagy proteins were assessed by immunoblotting or immunofluorescence. Loss of function experiments were performed by siRNA mediated knockdown of BAG3.

RESULTS

In comparison with healthy donors, increased BAG3 protein was observed in IPF lung homogenates and IPF fibroblasts. In addition, the substrate of BAG3-mediated autophagy, FLNC, was increased in IPF fibroblasts, implying insufficient activation of BAG3-dependent autophagy. Therapeutic modulation of this pathway using Aza and Ctd alone or in combination with the IPF therapy drug Pirf rescued the insufficient BAG3-mediated autophagy and decreased fibroblast proliferation. Such effects were observed upon therapeutic modulation of BAG3 but not upon knock down of BAG3 per se in IPF fibroblasts. Similarly, PCLS of IPF patients showed a significant decrease in collagen deposition in response to these drugs, either alone or in a more potent form in combination with Pirf.

CONCLUSIONS

Our study reveals that repurposing drugs that modulate autophagy regulating proteins render therapeutic benefits in IPF. Fine tuning of this pathway may hence signify a promising therapeutic strategy to ameliorate antifibrotic properties and augment the efficacy of current IPF therapy.

New Evidence of Canthariphily: Tilloidea transversalis (Coleoptera: Cleridae) Sequestering Cantharidin From Lydus trimaculatus (Coleoptera: Meloidae)

Cantharidin (CTD) is a defensive compound autogenously and exclusively produced by two phylogenetically related beetle families: Meloidae and Oedemeridae. Although this molecule usually acts as a strong deterrent against potential predators and parasites, some arthropod species, collectively named 'canthariphilous species', are attracted to CTD. Some species can sequester CTD from the CTD-producing species, using it as a chemical defense against enemies. The present paper focuses on the first-ever description of canthariphilous interactions between a checkered beetle species (Coleoptera: Cleridae) and a CTD -producing species. Field observations revealed individuals of the phytophagous beetle Tilloidea transversalis (Charpentier, 1825) (Coleoptera: Cleridae) biting individuals of the blister beetle Lydus trimaculatus (Fabricius, 1775) (Coleoptera: Meloidae). Laboratory behavioral experiments followed to verify if this peculiar behavior of T. transversalis also occurs on other co-occurring species. Moreover, chemical analyses were performed to assess whether T. transversalis can sequester CTD. Our results show that T. transversalis only attacks CTD-producing species. However, while chemical analyses prove that T. transversalis can sequester CTD from the hemolymph of L. trimaculatus, some clues (based on a CTD-baited traps sampling) suggest that this beetle, contrarily to other canthariphilous species, does not appear to show a high attraction to pure synthetic CTD. Thus, other unknown signals, alone or in combination with CTD, could be implicated in triggering the canthariphilous behaviors of T. transversalis.

Serine/Threonine Protein Phosphatase 2A Regulates the Transport of Axonal Mitochondria

Microtubule-based transport provides mitochondria to distant regions of neurons and is essential for neuronal health. To identify compounds that increase mitochondrial motility, we screened 1,641 small-molecules in a high-throughput screening platform. Indirubin and cantharidin increased mitochondrial motility in rat cortical neurons. Cantharidin is known to inhibit protein phosphatase 2A (PP2A). We therefore tested two other inhibitors of PP2A: LB-100 and okadaic acid. LB-100 increased mitochondrial motility, but okadaic acid did not. To resolve this discrepancy, we knocked down expression of the catalytic subunit of PP2A (PP2CA). This long-term inhibition of PP2A more than doubled retrograde transport of axonal mitochondria, confirming the importance of PP2A as a regulator of mitochondrial motility and as the likely mediator of cantharidin's effect.

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.

Oral ulcers in a finger-sucking child after cutaneous wart therapy

Common skin warts frequently appear on the fingers of children, a patient population in whom finger-sucking is a prevalent habit. Despite overlap between these two pediatric conditions, there are no well-reported specific precautions against the use of topical blistering wart treatments, such as trichloroacetic acid and cantharidin, in finger-sucking children with warts. We report the case of oral ulcers in a pediatric patient secondary to thumb-sucking after receiving treatment for multiple finger warts with combination cryotherapy, trichloroacetic acid, and cantharidin.

Safety and Efficacy of VP-102 (Cantharidin, 0.7% w/v) in Molluscum Contagiosum by Body Region: Post hoc Pooled Analyses from Two Phase III Randomized Trials

TRIAL REGISTRATION

>ClinicalTrials.gov identifier nos. NCT03377790 (for CAMP-1) and NCT03377803 (for CAMP-2).

BACKGROUND

VP-102 is drug-device combination product containing cantharidin (0.7% w/v) and has undergone Phase III clinical trials for the treatment of molluscum contagiosum (molluscum). Efficacy and safety may differ by body region due to variable skin anatomy.

OBJECTIVE

We investigated the pooled safety and efficacy of VP-102 by affected body region.

METHODS

Individuals at least two years of age with molluscum were randomized to topical VP-102 or vehicle once every 21 days until clear (maximum of four applications). Participants were assigned to body region groups where lesions were present at baseline. Body region lesion counts were recorded at each visit. Efficacy was measured by the percentage of participants with complete clearance of lesions by region. Pre-specified adverse events (AEs) were analyzed for those treated in the region on that visit.

RESULTS

Participants had a mean of two regions affected at baseline. Complete clearance was significantly higher in the VP-102-treated group than with vehicle application in all regions at the last visit (P<0.01 for each region). The incidence of pre-specified AEs was consistent across regions. However, these analyses were post hoc, and individual lesions were not tracked for efficacy.

CONCLUSION

VP-102 treatment shows consistent safety and efficacy across molluscum body regions.

Antiparasitic Effects of Potentially Toxic Beetles (Tenebrionidae and Meloidae) from Steppe Zones

Arthropods and specifically beetles can synthesize and/or sequester metabolites from dietary sources. In beetle families such as Tenebrionidae and Meloidae, a few studies have reported species with toxic defensive substances and antiparasitic properties that are consumed by birds. Here we have studied the antiparasitic activity of extracts from beetle species present in the habitat of the Great Bustard (Otis tarda) against four pathogen models (Aspergillus niger, Meloidogyne javanica, Hyalomma lusitanicum, and Trichomonas gallinae). The insect species extracted were Tentyria peiroleri, Scaurus uncinus, Blaps lethifera (Tenebrionidae), and Mylabris quadripunctata (Meloidae). M. quadripunctata exhibited potent activity against M. javanica and T. gallinae, while T. peiroleri exhibited moderate antiprotozoal activity. The chemical composition of the insect extracts was studied by gas chromatography coupled with mass spectrometry (GC-MS) analysis. The most abundant compounds in the four beetle extracts were hydrocarbons and fatty acids such as palmitic acid, myristic acid and methyl linoleate, which are characteristic of insect cuticles. The presence of cantharidin (CTD) in the M. quadripunctata meloid and ethyl oleate (EO) in T. peiroleri accounted for the bioactivity of their extracts.

Pharmacokinetics and tissue distribution of cantharidin after oral administration of aqueous extracts from Mylabris in rats

A sensitive gas chromatography-mass spectroscopy method was established for the determination of cantharidin (CTD) in rat plasma and liver homogenates. During the experiment, rats were randomly divided into two groups (low, high) and were administered aqueous extract of Mylabris compound for 7 days. Then, plasma and tissue samples were taken at different time points to study the pharmacokinetics and tissue distribution of CTD in rats. The selected reaction monitoring transitions for CTD and clofibrate (internal standard) were m/z 128 → 85 and m/z 169 → 141, respectively. The calibration curve ranged from 10.26 to 3,078 ng/ml for plasma and from 10.26 to 246.24 ng/ml for liver homogenates. The lower limits of quantification were 10.26 ng/ml for both plasma and liver. The intra- and inter-day precision and accuracy were <20% for both plasma and liver homogenates. Extraction recovery ranged from 89.21 to 103.61% for CTD in rat plasma and liver and from 83.79 to 102.74% for IS in rat plasma and liver. Matrix effects ranged from 93.06 to 110.44% for CTD and from 91.65 to 110.80% for IS.

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.

Cantharidin Induces Apoptosis and Promotes Differentiation of AML Cells Through Nuclear Receptor Nur77-Mediated Signaling Pathway

Background

Acute myeloid leukemia (AML) is a hematopoietic malignancy characterized by uncontrolled proliferation and accumulation of myeloblasts in the bone marrow (BM), blood, and other organs. The nuclear receptors Nur77 is a common feature in leukemic blasts and has emerged as a key therapeutic target for AML. Cantharidin (CTD), a main medicinal component of Mylabris (blister beetle), exerts an anticancer effect in multiple types of cancer cells.

Purpose

This study aims to characterize the anti-AML activity of CTD in vitro and in vivo and explore the potential role of Nur77 signaling pathway.

Study Design/Methods

The inhibition of CTD on cell viability was performed in different AML cells, and then the inhibition of CTD on proliferation and colony formation was detected in HL-60 cells. Induction of apoptosis and promotion of differentiation by CTD were further determined. Then, the potential role of Nur77 signaling pathway was assessed. Finally, anti-AML activity was evaluated in NOD/SCID mice.

Results

In our study, CTD exhibited potent inhibition on cell viability and colony formation ability of AML cells. Moreover, CTD significantly induced the apoptosis, which was partially reversed by Z-VAD-FMK. Meanwhile, CTD promoted the cleavage of caspases 8, 3 and PARP in HL-60 cells. Furthermore, CTD obviously suppressed the proliferation and induced the cell cycle arrest of HL-60 cells at G2/M phase. Meanwhile, CTD effectively promoted the differentiation of HL-60 cells. Notably, CTD transiently induced the expression of Nur77 protein. Interestingly, CTD promoted Nur77 translocation from the nucleus to the mitochondria and enhanced the interaction between Nur77 and Bcl-2, resulting in the exposure of the BH3 domain of Bcl-2, which is critical for the conversion of Bcl-2 from an antiapoptotic to a proapoptotic protein. Importantly, silencing of Nur77 attenuated CTD-induced apoptosis, reversed CTD-mediated cell cycle arrest and differentiation of HL-60 cells. Additionally, CTD also exhibited an antileukemic effect in NOD/SCID mice with the injection of HL-60 cells into the tail vein.

Conclusions

Our studies suggest that Nur77-mediated signaling pathway may play a critical role in the induction of apoptosis and promotion of differentiation by CTD on AML cells.

Anticancer Attributes of Cantharidin: Involved Molecular Mechanisms and Pathways

Cancer is a preeminent threat to the human race, causing millions of deaths each year on the Earth. Traditionally, natural compounds are deemed promising agents for cancer treatment. Cantharidin (CTD)-a terpenoid isolated from blister beetles-has been used extensively in traditional Chinese medicines for healing various maladies and cancer. CTD has been proven to be protein phosphatase 2A (PP2A) and heat shock transcription factor 1 (HSF-1) inhibitor, which can be potential targets for its anticancer activity. Albeit, it harbors some toxicities, its immense anticancer potential cannot be overlooked, as the cancer-specific delivery of CTD could help to rescue its lethal effects. Furthermore, several derivatives have been designed to weaken its toxicity. In light of extensive research, the antitumor activity of CTD is evident in both in vitro as well as in vivo cancer models. CTD has also proven efficacious in combination with chemotherapy and radiotherapy and it can also target some drug-resistant cancer cells. This mini-review endeavors to interpret and summarize recent information about CTD anticancer potential and underlying molecular mechanisms. The pertinent anticancer strength of CTD could be employed to develop an effective anticarcinogenic drug.

18-GA-Suc Modified Liposome Loading Cantharidin for Augmenting Hepatic Specificity: Preparation, Characterization, Antitumor Effects, and Liver-Targeting Efficiency

Cantharidin (CTD), a natural Chinese medicine constituent extracted from mylabris, is a potent drug against hepatocellular carcinoma. However, the clinical application of CTD was limited because of its toxicity and low solubility. In this work, a novel CTD-loaded liposome modified with 3-succinyl-30-stearyl glycyrrhetinic acid (18-GA-Suc-CTD-Lip) was prepared to enhance liver-targeting efficiency and antitumor activity. 18-GA-Suc-CTD-Lip and CTD-Lip were successfully prepared by film dispersion method and totally characterized. The antitumor effects in vitro were evaluated by cell proliferation inhibition assay, transwell assay, cell cycle analysis, and an apoptosis test. Pharmacokinetic and biodistribution were all investigated to precisely reveal liver-targeting efficiency of 18-GA-Suc-CTD-Lip in vivo. The IC₅₀ values of 18-GA-Suc-CTD-Lip in HepG2 (3.417 ± 0.165 nmol/L) and Huh-7 (4.478 ± 0.409 nmol/L) cells were much lower than that of CTD-Lip, indicating that antitumor effects of 18-GA-Suc-CTD-Lip were remarkable because of the modification of 18-GA-Suc. The maximum concentration in the liver of 18-GA-Suc-CTD-Lip (1.72 ± 0.14 μg/g) was more than twice CTD-Lip (0.75 ± 0.08 μg/g) at 30 min, illustrating that 18-GA-Suc-CTD-Lip possesses excellent liver-targeting efficiency. Conclusively, 18-GA-Suc-CTD-Lip could be a potential liver-targeting antitumor drug for hepatocellular carcinoma.

Draft Genome of a Blister Beetle Mylabris aulica

Mylabris aulica is a widely distributed blister beetle of the Meloidae family. It has the ability to synthesize a potent defensive secretion that includes cantharidin, a toxic compound used to treat many major illnesses. However, owing to the lack of genetic studies on cantharidin biosynthesis in M. aulica, the commercial use of this species is less extensive than that of other blister beetle species in China. This study reports a draft assembly and possible genes and pathways related to cantharidin biosynthesis for the M. aulica blister beetle using nanopore sequencing data. The draft genome assembly size was 288.5 Mb with a 467.8 Kb N50, and a repeat content of 50.62%. An integrated gene finding pipeline performed for assembly obtained 16,500 protein coding genes. Benchmarking universal single-copy orthologs assessment showed that this gene set included 94.4% complete Insecta universal single-copy orthologs. Over 99% of these genes were assigned functional annotations in the gene ontology, Kyoto Encyclopedia of Genes and Genomes, or Genbank non-redundant databases. Comparative genomic analysis showed that the completeness and continuity of our assembly was better than those of Hycleus cichorii and Hycleus phaleratus blister beetle genomes. The analysis of homologous orthologous genes and inference from evolutionary history imply that the Mylabris and Hycleus genera are genetically close, have a similar genetic background, and have differentiated within one million years. This M. aulica genome assembly provides a valuable resource for future blister beetle studies and will contribute to cantharidin biosynthesis.

Dual-Functional Liposomes with Carbonic Anhydrase IX Antibody and BR2 Peptide Modification Effectively Improve Intracellular Delivery of Cantharidin to Treat Orthotopic Hepatocellular Carcinoma Mice

Liposomal nanotechnology has a great potential to overcome the current major problems of chemotherapy. However, the lack of penetrability and targetability retards the successful delivery of liposomal carriers. Previously, we showed that BR2 peptide modification endowed cantharidin-loaded liposomes with intracellular penetration that enhanced the drug cytotoxic effects. Here, we aimed to improve the targeting delivery of drugs into cancer cells via highly expressed carbonic anhydrase IX (CA IX) receptors by modifying our previous catharidin-loaded BR2-liposomes with anti-CA IX antibody. A higher cellular uptake of dual-functional liposomes (DF-Lp) than other treatments was observed. Induction of CA IX over-expressing resulted in a higher cellular binding of DF-Lp; subsequently, blocking with excess antibodies resulted in a decreased cancer-cell association, indicating a specific targeting property of our liposomes towards CA IX expressed cells. After 3h tracking, most of the liposomes were located around the nucleus which confirmed the involvement of targeting intracellular delivery. Cantharidin loaded DF-Lp exhibited enhanced cytotoxicity in vitro and was most effective in controlling tumor growth in vivo in an orthotopic hepatocellular carcinoma model compared to other groups. Collectively, our results presented the advantage of the BR2 peptide and CA IX antibody combination to elevate the therapeutic potential of cantharidin loaded DF-liposomes.

Development of 11-DGA-3-O-Gal-Modified Cantharidin Liposomes for Treatment of Hepatocellular Carcinoma

Background: Liver cancer is a common malignant tumor worldwide, and its morbidity and mortality increase each year. The disease has a short course and high mortality, making it a serious threat to human health. Purpose: The objective of this study was to create novel liver-targeting nanoliposomes to encapsulate cantharidin (CTD) as a potential treatment for hepatic carcinoma. Methods: 3-Galactosidase-30-stearyl deoxyglycyrrhetinic acid (11-DGA-3-O-Gal)-modified liposomes (11-DGA-3-O-Gal-CTD-lip) for the liver-targeted delivery of CTD were prepared via the film-dispersion method and characterized. In vitro analyses of the effects on cellular cytotoxicity, cell migration, cell cycle, and cell apoptosis were carried out and an in vivo pharmacokinetics study and tissue distribution analysis were performed. Results: Compared with unmodified liposomes (CTD-lip), 11-DGA-3-O-Gal-CTD-lip showed higher cytotoxicity and increased the inhibition of HepG2 cell migration, but they did not increase the apoptotic rate of cells. The inhibition mechanism of 11-DGA-3-O-Gal-CTD-lip on hepatocellular carcinoma was partly through cell cycle arrest at the S phase. Analysis of pharmacokinetic parameters indicated that 11-DGA-3-O-Gal-CTD-lip were eliminated more rapidly than CTD-lip. Regarding tissue distribution, the targeting efficiency of 11-DGA-3-O-Gal-CTD-lip to the liver was (41.15 ± 3.28)%, relative targeting efficiency was (1.53 ± 0.31)%, relative uptake rate was( 1.69 ± 0.37)%, and peak concentration ratio was (2.68 ± 0.12)%. Conclusion: 11-DGA-3-O-Gal-CTD-lip represent a promising nanocarrier for the liver-targeted delivery of antitumor drugs to treat hepatocellular carcinoma.

Breaking Glucose Transporter 1/Pyruvate Kinase M2 Glycolytic Loop Is Required for Cantharidin Inhibition of Metastasis in Highly Metastatic Breast Cancer

Aerobic glycolysis plays a decisive role in cancer growth. However, its role in cancer metastasis was rarely understood. Cantharidin a natural compound from an arthropod insect cantharis exerts potent anticancer activity. Here we found cantharidin possesses significant anti-metastatic activity on breast cancer dependent on inhibition of aerobic glycolysis. Cantharidin indicates significant inhibition on migration and invasion of breast cancer cells, angiogenesis in vitro, and inhibits breast cancer cells metastasizing to liver and lung in vivo. Subsequent results revealed that cantharidin decreases the extracellular acidification rates (ECAR) but increases the oxygen consumption rates (OCR) in high metastatic cells, leading to suppression of aerobic glycolysis. This was considered to be due to inhibiting the activity of pyruvate kinase (PK) and further blocking pyruvate kinase M2 (PKM2) translocation in nucleus. Fructose-1,6-bisphosphate (FBP) and L-cysteine can significantly reverse cantharidin inhibition on breast cancer cell migration, invasion, and PKM2 translocation. Furthermore, glucose transporter 1 (GLUT1) forming a metabolic loop with PKM2 is downregulated, as well as epidermal growth factor receptor (EGFR), the regulator of the glycolytic loop. Totally, cantharidin inhibits the PKM2 nuclear translocation and breaks GLUT1/PKM2 glycolytic loop, resulting in aerobic glycolysis transformation to oxidation and subsequent reversing the metastases in breast cancer. Based on inhibiting multi signals mediated aerobic glycolysis, cantharidin could be prospectively used for prevention of metastasis in breast cancer patients.

Antiparasitic Properties of Cantharidin and the Blister Beetle Berberomeloe majalis (Coleoptera: Meloidae)

Cantharidin (CTD) is a toxic monoterpene produced by blister beetles (Fam. Meloidae) as a chemical defense against predators. Although CTD is highly poisonous to many predator species, some have evolved the ability to feed on poisonous Meloidae, or otherwise beneficially use blister beetles. Great Bustards, Otis tarda, eat CTD-containing Berberomeloe majalis blister beetles, and it has been hypothesized that beetle consumption by these birds reduces parasite load (a case of self-medication). We examined this hypothesis by testing diverse organisms against CTD and extracts of B. majalis hemolymph and bodies. Our results show that all three preparations (CTD and extracts of B. majalis) were toxic to a protozoan (Trichomonas vaginalis), a nematode (Meloidogyne javanica), two insects (Myzus persicae and Rhopalosiphum padi) and a tick (Hyalomma lusitanicum). This not only supports the anti-parasitic hypothesis for beetle consumption, but suggests potential new roles for CTD, under certain conditions.

Blister beetle dermatitis caused by cantharidin in South Sudan in Op TRENTON: a case series

Cantharidin-producing blister beetles are found worldwide. The pathognomonic feature of their toxin is a blistering dermatitis that presents an environmental health hazard. Cutaneous exposure to cantharidin can produce blistering dermatitis, most commonly seen on exposed skin, in the Bentiu region of South Sudan. This should be treated with appropriate cleaning, debridement and regular dressing changes to cope with extensive initial exudate. The best dressing combinations found were initial treatment with povidone-iodine and hydrocolloid, followed by hydrocolloid only. Hydrocolloid dressings were found to be the most effective at staying in place with South Sudan's high humidity. Prevention strategies should include covering exposed skin, wearing wide-brimmed hats, neck scarves and enclosed footwear, and avoidance of working under white light. Medical personnel should engage with the chain of command to include appropriate force protection education within the arrivals brief.

The natural anticancer agent cantharidin alters GPI-anchored protein sorting by targeting Cdc1-mediated remodeling in endoplasmic reticulum

Cantharidin (CTD) is a potent anticancer small molecule produced by several species of blister beetle. It has been a traditional medicine for the management of warts and tumors for many decades. CTD suppresses tumor growth by inducing apoptosis, cell cycle arrest, and DNA damage and inhibits protein phosphatase 2 phosphatase activator (PP2A) and protein phosphatase 1 (PP1). CTD also alters lipid homeostasis, cell wall integrity, endocytosis, adhesion, and invasion in yeast cells. In this study, we identified additional molecular targets of CTD using a Saccharomyces cerevisiae strain that expresses a cantharidin resistance gene (CRG1), encoding a SAM-dependent methyltransferase that methylates and inactivates CTD. We found that CTD specifically affects phosphatidylethanolamine (PE)-associated functions that can be rescued by supplementing the growth media with ethanolamine (ETA). CTD also perturbed endoplasmic reticulum (ER) homeostasis and cell wall integrity by altering the sorting of glycosylphosphatidylinositol (GPI)-anchored proteins. A CTD-dependent genetic interaction profile of CRG1 revealed that the activity of the lipid phosphatase cell division control protein 1 (Cdc1) in GPI-anchor remodeling is the key target of CTD, independently of PP2A and PP1 activities. Moreover, experiments with human cells further suggested that CTD functions through a conserved mechanism in higher eukaryotes. Altogether, we conclude that CTD induces cytotoxicity by targeting Cdc1 activity in GPI-anchor remodeling in the ER.

Inhibitors of Serine/Threonine Protein Phosphatases: Biochemical and Structural Studies Provide Insight for Further Development

BACKGROUND

The reversible phosphorylation of proteins regulates many key functions in eukaryotic cells. Phosphorylation is catalyzed by protein kinases, with the majority of phosphorylation occurring on side chains of serine and threonine residues. The phosphomonoesters generated by protein kinases are hydrolyzed by protein phosphatases. In the absence of a phosphatase, the half-time for the hydrolysis of alkyl phosphate dianions at 25º C is over 1 trillion years; knon ~2 x 10-20 sec-1. Therefore, ser/thr phosphatases are critical for processes controlled by reversible phosphorylation.

METHODS

This review is based on the literature searched in available databases. We compare the catalytic mechanism of PPP-family phosphatases (PPPases) and the interactions of inhibitors that target these enzymes.

RESULTS

PPPases are metal-dependent hydrolases that enhance the rate of hydrolysis ([kcat/kM]/knon ) by a factor of ~1021, placing them among the most powerful known catalysts on earth. Biochemical and structural studies indicate that the remarkable catalytic proficiencies of PPPases are achieved by 10 conserved amino acids, DXH(X)~26DXXDR(X)~20- 26NH(X)~50H(X)~25-45R(X)~30-40H. Six act as metal-coordinating residues. Four position and orient the substrate phosphate. Together, two metal ions and the 10 catalytic residues position the phosphoryl group and an activated bridging water/hydroxide nucleophile for an inline attack upon the substrate phosphorous atom. The PPPases are conserved among species, and many structurally diverse natural toxins co-evolved to target these enzymes.

CONCLUSION

Although the catalytic site is conserved, opportunities for the development of selective inhibitors of this important group of metalloenzymes exist.

Serine/threonine protein phosphatase 5 is a potential therapeutic target in cholangiocarcinoma

BACKGROUND & AIMS

Few molecules are currently verified to be actionable drug targets in cholangiocarcinoma (CCA). Serine/threonine protein phosphatase 5 (PP5) dysregulation is related to several malignancies. However, the role of PP5 in CCA is poorly defined.

METHODS

Colony and tumorsphere formation assays were conducted to establish the role of PP5 in CCA tumorigenesis. Cantharidin (CTD) and norcantharidin (NCTD), both potent PP5 inhibitors, were used in in vitro and in vivo experiments to validate the potential therapeutic role of PP5.

RESULTS

Increased cell growth, colony formation and tumorsphere formation were observed in PP5-overexpressing CCA cells, whereas PP5 knockdown by shRNA decreased cell growth and colony formation. Tumours from HuCCT1 xenograft-bearing mice treated with PP5-shRNA showed decreased growth and increased AMP-activated protein kinase (AMPK) phosphorylation. Furthermore, CTD treatment decreased cell viability, reduced PP5 activity and enhanced AMPK phosphorylation in CCA cell lines. Overexpressing PP5 or enhancing PP5 activity suppressed AMPK phosphorylation and decreased CTD-induced cell death. Suppressing p-AMPK with siRNA or inhibitors also decreased CTD-induced cell death, suggesting a pivotal role for PP5-AMPK cascades in CCA. Immunoprecipitation revealed that PP5 interacted with AMPK. Importantly, treatment of HuCCT1 xenograft-bearing mice with NCTD, a CTD analogue with a lower systemic toxicity in vivo, suppressed PP5 activity, increased p-AMPK and reduced tumour volume.

CONCLUSIONS

Protein phosphatase 5 negatively regulates AMPK phosphorylation and contributes to CCA aggressiveness; thus, PP5 may be a potential therapeutic target in CCA.

Cantharidin-encapsulated thermal-sensitive liposomes coated with gold nanoparticles for enhanced photothermal therapy on A431 cells

Purpose

Plasmonic nanostructure-mediated photothermal therapy (PTT) is a promising alternative therapy for the treatment of skin cancer and other diseases. However, the insufficient efficiency of PTT at irradiation levels tolerable to tissues and the limited biodegradability of nanomaterials are still crucial challenges. In this study, a novel nanosystem for PTT based on liposome–nanoparticle assemblies (LNAs) was established.

Materials and methods

Thermal-sensitive liposomes (TSLs) encapsulating cantharidin (CTD) were coated with gold nanoparticles (GNPs) and used in near-infrared (NIR) illumination-triggered PTT and thermally induced disruption on A431 cells.

Results

The coated GNPs disintegrated into small particles of 5–6 nm after disruption of TSLs, allowing their clearance by the liver and kidneys. CTD encapsulated in the TSLs was released into cytoplasm after PTT. The released CTD increased the apoptosis of PTT-treated tumor cells by blocking the heat shock response (HSR) and inhibiting the expression of HSP70 and BAG3 inhibiting the expression of HSP70 and BAG3 with the synergistic enhancement of CTD, the new nanosystem CTD-encapsulated TSLs coated with GNPs (CTD-TSL@GNPs) had an efficient PTT effect using clinically acceptable irradiation power (200 mW//cm²) on A431 cells.

Conclusion

The developed CTD-TSL@GNPs may be a promising PTT agent for clinical skin cancer therapy.

Cantharidin suppresses cell growth and migration, and activates autophagy in human non-small cell lung cancer cells

Cantharidin (CTD), a component of Mylabris (blister beetle), is a traditional Chinese medicine that exerts an anticancer effect in multiple types of cancer cells. The aim of the present study was to investigate whether CTD exhibited anti-metastatic and inhibitory cell proliferation effects against human non-small cell lung cancer (NSCLC) A549 cells, and the possible underlying mechanism by which this occurs. The results of the present study demonstrated that CTD arrested proliferation, suppressed invasion and migration and induced apoptosis in A549 cells in vitro. Alterations of apoptosis-associated protein levels, including B-cell lymphoma-2 (Bcl-2), Bcl-associated X (Bax) and active caspase-3, were detected. Furthermore, the present study demonstrated that CTD activated autophagy through downregulation of p62 expression and upregulation of microtubule-associated proteins 1A/1B light chain 3B and Beclin-1 expression. Additionally, western blot analysis identified that CTD inhibited the phosphatidylinositol 3-kinase (PI3K)/RAC serine/threonine protein kinase (Akt)/mechanistic target of rapamycin (mTOR) signaling pathway in NSCLC, demonstrating that the levels of phosphorylated (p-)Akt, p-mTOR, phosphorylated ribosomal p70S6 protein kinase (p-p70-S6K) and cyclin D1 were significantly decreased following treatment with CTD. In conclusion, the results of the present study indicated that CTD impeded cell growth and migration by inhibiting PI3K/Akt/mTOR signaling in NSCLC, and promoted autophagy and apoptosis. CTD exhibited anticancer activity against NSCLC in vitro, revealing it as a potential candidate for the treatment of NSCLC.

Omics-Based Platform for Studying Chemical Toxicity Using Stem Cells

The new strategy for chemical toxicity testing and modeling is to use in vitro human cell-based assays in conjunction with quantitative high-throughput screening (qHTS) technology, to identify molecular mechanisms and predict in vivo responses. Stem cells are more physiologically relevant than immortalized cell lines because of their unique proliferation and differentiation potentials. We established a robust two stem cells-two lineages assay system, encompassing human mesenchymal stem cells (hMSCs) along osteogenesis and human induced pluripotent stem cells (hiPSCs) along hepatogenesis. We performed qHTS phenotypic screening of LOPAC1280 and identified 38 preliminary hits for hMSCs. This was followed by validation of a selected number of hits and determination of their IC₅₀ values and mechanistic studies of idarubicin and cantharidin treatments using proteomics and bioinformatics. In general, hiPSCs were more sensitive than hMSCs to chemicals, and differentiated progenies were less sensitive than their progenitors. We showed that chemical toxicity depends on both stem cell types and their differentiation stages. Proteomics identified and quantified over 3000 proteins for both stem cells. Bioinformatics identified apoptosis and G2/M as the top pathways conferring idarubicin toxicity. Our Omics-based assays of stem cells provide mechanistic insights into chemical toxicity and may help prioritize chemicals for in-depth toxicological evaluations.

Liposomes equipped with cell penetrating peptide BR2 enhances chemotherapeutic effects of cantharidin against hepatocellular carcinoma

A main hurdle for the success of tumor-specific liposomes is their inability to penetrate tumors efficiently. In this study, we incorporated a cell-penetrating peptide BR2 onto the surface of a liposome loaded with the anticancer drug cantharidin (CTD) to create a system targeting hepatocellular carcinoma (HCC) cells more efficiently and effectively. The in vitro cytotoxicity assay comparing the loaded liposomes’ effects on hepatocellular cancer HepG2 and the control Miha cells showed that CTD-loaded liposomes had a stronger anticancer effect after BR2 modification. The cellular uptake results of HepG2 and Miha cells further confirmed the superior ability of BR2-modified liposomes to penetrate cancer cells. The colocalization study revealed that BR2-modified liposomes could enter tumor cells and subsequently release drugs. A higher efficiency of delivery by BR2 liposomes as compared to unmodified liposomes was evident by evaluation of the HepG2 tumor spheroids penetration and inhibition. The biodistribution studies and anticancer efficacy results in vivo showed the significant accumulation of BR2-modified liposomes into tumor sites and an enhanced tumor inhibition. In conclusion, BR2-modified liposomes improve the anticancer potency of drugs for HCC.

Roles of p38 and JNK protein kinase pathways activated by compound cantharidin capsules containing serum on proliferation inhibition and apoptosis of human gastric cancer cell line

The aim of the present study was to investigate the inhibitory effect of compound cantharides capsules (CCCs) on the viability and apoptosis of human gastric cancer cell lines, BGC-823 and SGC-7901, and to detect its regulation of gene expression levels, as well as its inhibition mechanisms. Each cell line was grouped into a control group, CCC serum group, 5-fluorouracil (5-FU) group, combination therapy group (CCC serum + 5-FU) and serum control group. Growth curves were measured and flow cytometry was used to detect cell apoptosis and cell viability. The mRNA expression level of proliferation-related C-MYC and p53 genes were assayed by reverse transcription-quantitative polymerase chain reaction. Protein phosphorylation levels of proliferating cell nuclear antigen, p38 mitogen-activated protein kinase, extracellular signal-related kinase 1/2, c-Jun N-terminal kinase (JNK) and IκB were assayed by western blotting. The combined CCC serum and 5-FU group exhibited a higher inhibition rate in both cell lines and CCC serum therapy demonstrated a similar effect to 5-FU treatment, as demonstrated in the MTT and cell growth assay. Combined therapy significantly decreased the C-MYC mRNA expression levels and increased p53 mRNA expression levels (P<0.05). Combined therapy of 5-FU and CCC was more significant compared with CCC serum or 5-FU only (P<0.05). P38 and JNK-related protein phosphorylation are involved in apoptosis initiated by CCC combined 5-FU therapy. Combined therapy was able to significantly inhibit human gastric cancer cell growth (P<0.05), and advance cell apoptosis compared with CCC serum only. CCC serum resulted in downregulation of the c-Myc gene and upregulation of the p53 gene. p38 and JNK-related protein phosphorylation is involved in the inhibition of cell viability and apoptosis of human gastric cancer cell lines.

Augmented Anticancer Effects of Cantharidin with Liposomal Encapsulation: In Vitro and In Vivo Evaluation

PEGylated liposomes have received much attention as pharmaceutical carriers to deliver chemotherapeutic agents for therapeutic purpose. The aim of this study was to prepare and characterize PEGylated liposome of cantharidin and investigate its therapeutic effect on human hepatocellular carcinoma treatment in vitro and in vivo. Liposomal cantharidin was evaluated for their anticancer effects in vitro using human hepatocellular carcinoma HepG2 cells and in vivo using HepG2-bearing nude mice compared to free drug. PEGylated liposome of cantharidin had a particle size of 129.9 nm and a high encapsulation efficacy of approximately 88.9%. The liposomal cantharidin had a higher anti-proliferative effect vis-à-vis free cantharidin in inducing G2/M cell cycle arrest and apoptosis. Liposomal cantharidin killed more HepG2 cancer cells at the same concentration equivalent to free cantharidin. Further study in vivo also showed that liposomal cantharidin achieved a higher tumor growth inhibition efficacy than free drug on hepatocellular carcinoma. As our study exhibited enhanced cytotoxicity against HepG2 cells and augmented tumor inhibitory effects in vivo, the results validate the potential value of cantharidin-liposome in improving the therapeutic efficacy of cantharidin for liver cancer.

Cantharidin alters the expression of genes associated with the NKG2D-associated immune response in TSGH-8301 human bladder carcinoma cells

Cantharidin (CTD) is a natural toxin in beetles of the Mylabris genus (blister beetle), which has been revealed to induce cell death in various types of human cancer cells. However, to the best of our knowledge, no previous studies have investigated the effect of CTD on the expression of genes and their associated signaling pathways in human bladder carcinoma cells. In the present study, CTD-induced cell morphological changes and apoptosis were observed using phase-contrast microscopy and the terminal deoxynucleotidyl transferase dUTP nick end labeling assay, respectively, in TSGH-8301 human bladder carcinoma cells. In addition, a complementary DNA microarray analysis demonstrated that CTD treatment led to a >2-fold upregulation of 269 genes. For example, the DNA damage-associated gene DNA-damage-inducible transcript 3 had a 4.75-fold upregulation. Furthermore, another 286 genes were >2-fold downregulated in response to CTD treatment. Matrix-remodeling associated 5, which is associated with cell migration and invasion, was downregulated 7.98-fold.

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.

Anticancer effects of cantharidin in A431 human skin cancer (Epidermoid carcinoma) cells in vitro and in vivo

Cantharidin (CTD), a potential anticancer agent of Traditional Chinese Medicine has cytotxic effects in different human cancer cell lines. The cytotoxic effects of CTD on A431 human skin cancer (epidermoid carcinoma) cells in vitro and in A431 cell xenograft mouse model were examined. In vitro, A431 human skin cell were treated with CTD for 24 and 48 h. Cell phase distribution, ROS production, Ca²⁺ release, Caspase activity and the level of apoptosis associated proteins were measured. In vivo, A431 cell xenograft mouse model were examined. CTD-induced cell morphological changes and decreased percentage of viable A431 cells via G0/G1 phase arrest and induced apoptosis. CTD-induced G0/G1 phase arrest through the reduction of protein levels of cyclin E, CDK6, and cyclin D in A431 cells. CTD-induced cell apoptosis of A431 cells also was confirm by DNA gel electrophoresis showed CTD-induced DNA fragmentation. CTD reduced the mitochondrial membrane potential and stimulated release of cytochrome c, AIF and Endo G in A431 cells. Flow cytometry demonstrated that CTD increased activity of caspase-8, -9 and -3. However, when cells were pretreated with specific caspase inhibitors activity was reduced and cell viability increased. CTD increased protein levels of death receptors such as DR4, DR5, TRAIL and levels of the active form of caspase-8, -9 and -3 in A431 cells. AIF and Endo G proteins levels were also enhanced by CTD. In vivo studies showed that CTD significantly inhibited A431 cell xenograft tumors in mice. Taken together, these in vitro and in vivo results provide insight into the mechanisms of CTD on cell growth and tumor production. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 723-738, 2017.

Cantharidin Overcomes Imatinib Resistance by Depleting BCR-ABL in Chronic Myeloid Leukemia

Cantharidin (CTD) is an active compound isolated from the traditional Chinese medicine blister beetle and displayed anticancer properties against various types of cancer cells. However, little is known about its effect on human chronic myeloid leukemia (CML) cells, including imatinib-resistant CML cells. The objective of this study was to investigate whether CTD could overcome imatinib resistance in imatinib-resistant CML cells and to explore the possible underlying mechanisms associated with the effect. Our results showed that CTD strongly inhibited the growth of both imatinib-sensitive and imatinib-resistant CML cells. CTD induced cell cycle arrest at mitotic phase and triggered DNA damage in CML cells. The ATM/ATR inhibitor CGK733 abrogated CTD-induced mitotic arrest but promoted the cytotoxic effects of CTD. In addition, we demonstrated that CTD downregulated the expression of the BCR-ABL protein and suppressed its downstream signal transduction. Real-time quantitative PCR revealed that CTD inhibited BCR-ABL at transcriptional level. Knockdown of BCR-ABL increased the cell-killing effects of CTD in K562 cells. These findings indicated that CTD overcomes imatinib resistance through depletion of BCR-ABL. Taken together, CTD is an important new candidate agent for CML therapy.

3-hydroxy-3-methyl glutaryl coenzyme A reductase: an essential actor in the biosynthesis of cantharidin in the blister beetle Epicauta chinensis Laporte

Cantharidin (C(10)H(12)O(4)) is a monoterpene defensive toxin in insects involved in chemical defence as well as in courtship and mating behaviours. It is relatively well known in the medical literature because of its high anticancer activity and as an effective therapy for molluscum contagiosum. However, little is known about its biosynthesis pathway in vivo, and no enzyme involved in cantharidin biosynthesis has been identified. The purpose of this study was to identify the crucial enzyme that is involved in the biosynthesis of cantharidin. Using the homology cloning method, a 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGR) gene, the rate-limiting enzyme in the mevalonate pathway, was cloned from the blister beetle Epicauta chinensis. Quantitative reverse transcription PCR and gas chromatography methods revealed that the HMGR transcripts had a positive correlation with cantharidin production in the beetles (R = 0.891). RNA interference (RNAi) knockdown of HMGR mRNA expression was achieved by microinjection of a specific double-stranded RNA with more than 90% RNAi efficiency, and an apparent decrease of cantharidin production was observed. Furthermore, the HMGR mRNA was greatly upregulated by exogenous juvenile hormone III (JH III), and cantharidin production was also raised in males; however, when injecting the JH III with RNAi of HMGR mRNA at the same time, cantharidin production did not rise. These results demonstrate that HMGR is an essential enzyme in cantharidin biosynthesis in the blister beetle E. chinensis, which further verifies previous research results demonstrating that cantharidin is synthesized de novo by the mevalonate pathway in blister beetles.

Synthesis of Canthardin Sulfanilamides and Their Acid Anhydride Analogues via a Ring-Opening Reaction of Activated Aziridines and Their Associated Pharmacological Effects

The cantharidinimide derivatives, 5a-h, including sulfanilamides containing pyrimidyl, pyrazinyl, hydrogen, thiazolyl, and oxazolyl groups were synthesized. Modification of cantharidinimide by means of the reaction of activated aziridine ring opening led to the discovery of a novel class of antitumor compounds. The analogues 10i-k, 11l-n, 12o-p, and 16q-s were obtained from treating cantharidinimide 6 and analogues (7, 8, and 13) with activated aziridines, which produced a series of ring-opened products including normal and abnormal types. Some of these compounds showed cytotoxic effects in vitro against HL-60, Hep3B, MCF7, and MDA-MB-231 cancer cells. The most potent cytostatic compound, N-cantharidinimido-sulfamethazine (5a), exhibited anti-HL-60 and anti-Hep3B cell activities. Two compounds 5g and 5h displayed slight effects on the Hep3B cell line, while the other compounds produced no response in these four cell lines.

Synthesis and Biological Evaluation of Norcantharidin Derivatives Possessing an Aromatic Amine Moiety as Antifungal Agents

Based on the structure of naturally produced cantharidin, different arylamine groups were linked to the norcantharidin scaffold to provide thirty six compounds. Their structures were confirmed by melting point, ¹H-NMR, (13)C-NMR and HRMS-ESI studies. These synthetic compounds were tested as fungistatic agents against eight phytopathogenic fungi using the mycelium growth rate method. Of these thirty six derivatives, seven displayed stronger antifungal activity than did norcantharidin, seven showed higher activity than did cantharidin and three exhibited more significant activity than that of thiabendazole. In particular, 3-(3'-chloro-phenyl)carbamoyl norcantharidate II-8 showed the most significant fungicidal activity against Sclerotinia fructigena and S. sclerotiorum, with IC50 values of 0.88 and 0.97 μg/mL, respectively. The preliminary structure-activity relationship data of these compounds revealed that: (1) the benzene ring is critical for the improvement of the spectrum of antifungal activity (3-phenylcarbamoyl norcantharidate II-1 vs norcantharidin and cantharidin); (2) among the three sites, including the C-2', C-3' and C-4' positions of the phenyl ring, the presence of a halogen atom at the C-3'position of the benzene ring caused the most significant increase in antifungal activity; (3) compounds with strongly electron-drawing or electron-donating groups substitutions were found to have a poor antifungal activity; and (4) compared with fluorine, bromine and iodine, chlorine substituted at the C-3' position of the benzene ring most greatly promoted fungistatic activity. Thus, compound II-8 has emerged as new lead structure for the development of new fungicides.

Cantharidin modulates the E2F1/MCM7-miR-106b-93/p21-PTEN signaling axis in MCF-7 breast cancer cells

Cantharidin (CTD) is one of numerous natural products used in traditional Chinese medicine for the treatment of cancer. The aim of the present study was to investigate the effects of CTD on changes in the expression of microRNAs (miRNAs/miRs) and to explore its anti-proliferative effect on MCF-7 breast cancer cells. The proliferation of MCF-7 cells was measured by performing an MTT assay. MCF-7 cells were treated with various concentrations of CTD for 48 h, and the expression profiles of miRNAs in CTD-treated and -untreated MCF-7 cells were detected using miRNA microarray chips. The array data were confirmed by reverse transcription-quantitative polymerase chain reaction and protein expression levels were measured by western blot analysis. The 50% inhibitory concentration of CTD was 1.75 µg/ml following treatment for 48 h and CTD significantly inhibited the proliferation of MCF-7 cells in a dose-dependent manner (P<0.01). Furthermore, microarray analysis identified 35 miRNAs that were up-regulated (fold change ≥2.0 and P<0.01) and 45 miRNAs that were down-regulated (fold change ≤ 0.5 and P<0.01) in response to CTD treatment. Thus, numerous CTD-induced miRNAs appeared to be associated with breast cancer. Notably, CTD repressed the expression of miR-106b-93, its host gene MCM7 and its transcription factor E2F1. In addition, CTD induced an increase in the protein expression levels of miR-106b-93 target genes p21 and phosphatase and tensin homolog. These observations suggested that the modulation of miRNA expression is an important mechanism underlying the biological effects of CTD in breast cancer.

Cantharidin induces DNA damage and inhibits DNA repair-associated protein levels in NCI-H460 human lung cancer cells

Cantharidin is one of the major compounds from mylabris and it has cytotoxic effects in many different types of human cancer cells. Previously, we found that cantharidin induced cell death through cell cycle arrest and apoptosis induction in human lung cancer NCI-H460 cells. However, cantharidin-affected DNA damage, repair, and associated protein levels in NCI-H460 cells have not been examined. In this study, we determined whether cantharidin induced DNA damage and condensation and altered levels of proteins in NCI-H460 cells in vitro. Incubation of NCI-H460 cells with 0, 2.5, 5, 10, and 15 μM of cantharidin caused a longer DNA migration smear (comet tail). Cantharidin also increased DNA condensation. These effects were dose-dependent. Cantharidin (5, 10, and 15 μM) treatment of NCI-H460 cells reduced protein levels of ataxia telangiectasia mutated (ATM), breast cancer 1, early onset (BRCA-1), 14-3-3 proteins sigma (14-3-3σ), DNA-dependent serine/threonine protein kinase (DNA-PK), O(6) -methylguanine-DNA methyltransferase (MGMT), and mediator of DNA damage checkpoint protein 1 (MDC1). Protein translocation of p-p53, p-H2A.X (S140), and MDC1 from cytoplasm to nucleus was induced by cantharidin in NCI-H460 cells. Taken together, this study showed that cantharidin caused DNA damage and inhibited levels of DNA repair-associated proteins. These effects may contribute to cantharidin-induced cell death in vitro.

ISOLATION AND FUNCTIONAL ANALYSIS OF McMenA, A GENE ENCODING A 1,4-DIHYDROXY-2-NAPHTHOATE OCTAPRENYLTRANSFERASE IN Mylabris cichorii

Cantharidin is a biomolecule with a role in host defense that can also be used as an anticancer drug. The in vivo biosynthetic pathway for cantharidin has been the subject of debate for several decades and the mechanism is not yet completely understood. To study the biosynthetic pathway of cantharidin in blister beetles, Mylabris cichori, a full-length MenA (McMenA) cDNA was cloned based on the partial sequence of the MenA gene from a suppression subtractive hybridization (SSH) library of male and female adult M. cichorii. The cDNA was 1264 base pairs (bp) with an open reading frame of 1026 bp nucleotides encoding a 341 amino acid protein. Analysis of the McMenA amino acid sequence showed that the aspartate rich motif N/DDxxD represented binding sites for prenyl diphosphate via a Mg(2+) ion. Phylogenetic analysis showed that McMenA was most closely related to MenA of Tribolium castaneum, and the amino acid sequence similarity was 86%. The expression pattern of McMenA in adults was analyzed using RT-qPCR, and we found that the highest expression of McMenA occurred during 22-25 days in the sex-separate breeding males, while the lowest expression occurred in females at the same time. Injection with a specific double-strand RNA (dsRNA) of McMenA led to a significant reduction of McMenA mRNA levels after 24 h. Cantharidin and ATP concentrations dropped around the same time. Together, our data showed that the McMenA gene might be involved in cantharidin biosynthesis.