Analysis of gene expression profiles in human HL-60 cell exposed to cantharidin using cDNA microarray

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.

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.

Cantharidic acid induces apoptosis of human leukemic HL-60 cells via c-Jun N-terminal kinase-regulated caspase-8/-9/-3 activation pathway

Cantharidin, a natural toxin from blister beetles, has shown potent anticancer activities on many solid tumor cells. Recently, cantharidin and its analogue, norcantharidin, were also shown to suppress nonsolid tumors such as chronic myeloid leukemia, acute myeloid leukemia (AML), and leukemic stem cells. However, there is no available information to address the effects of cantharidic acid (CAC), a hydrolysis product of cantharidin, on human AML cells. The present study showed that CAC, at a range of concentrations (0-20 μM), concentration-dependently inhibited cell proliferation in the HL-60 AML cell line. Western blot and flow cytometric assays demonstrated that CAC induced several features of apoptosis such as sub G1-phase cell increase, phosphatidylserine (PS) externalization, and significantly activated proapoptotic signaling including caspase-8, -9, and -3 activation and poly(ADP-ribose) polymerase (PARP) cleavage in HL-60 AML cells. Moreover, treatment of HL-60 cells with CAC induced concentration- and time- dependent activation of p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK). Only JNK-, but not p38 MAPK-specific inhibitor can reverse the CAC-induced activation of the caspase-8, -9, and -3. We concluded that CAC can induce apoptosis in human leukemic HL-60 cells via a caspases-dependent pathway, and that the apoptosis-inducing effect of CAC can be regulated by JNK activation signaling.

The targeting effect of Hm2E8b-NCTD-liposomes on B-lineage leukaemia stem cells is associated with the HLF-SLUG axis

To identify an agent with specific activity against B-lineage leukaemia stem cells (B-LSCs), we generated norcantharidin (NCTD)-encapsulated liposomes modified with a novel humanised anti-human CD19 monoclonal antibody, Hm2E8b (Hm2E8b-NCTD-liposomes). These liposomes were specially designed to recognise and kill B-LSCs in vitro, and to decrease non-specific cytotoxicity to untargeted cells. Hm2E8b-NCTD-liposomes selectively ablated B-LSCs through targeting hepatic leukaemia factor (HLF), which is implicated in haematopoietic stem cell regulation and is overexpressed in LSCs. Hm2E8b-NCTD-liposomes decreased HLF protein levels and induced apoptosis in the HAL-01 cell line harbouring the oncoprotein E2A-HLF. This resulted in modulation of the expression of several molecules that govern survival pathways, including HLF, SLUG, NFIL3 and C-Myc, thereby causing the induction of p53 and the mitochondrial caspase cascade. Therefore, the potent in vitro effect of Hm2E8b-NCTD-liposomes on B-LSC activity and survival pathways have the potential to be exploited clinically with appropriate drug combinations.

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-mediated ultrastructural and biochemical changes in mitochondria lead to apoptosis and necrosis in murine Dalton's lymphoma

Cantharidin, a type of terpenoid, is the blistering agent of blister beetles frequently used in traditional medicine. The isolation and anticancer activity of cantharidin from blister beetles, Mylabris cichorii has been recently reported by us. This study deals with changes in mitochondrial structure and function and understanding their significance in the underlying mechanism(s) in cantharidin-mediated antitumor effects in Dalton's lymphoma (DL) bearing mice. Cantharidin treatment caused the appearance of abnormal mitochondrial features which included roundish mitochondria with thickened membranes, irregularity in cristae, and appearance of small and large size vacuoles in mitochondria of DL cells. Cantharidin treatment resulted in a decrease in mitochondrial reduced glutathione, succinate dehydrogenase activity, mitochondrial membrane potential, and induced apoptosis and necrosis in DL cells. The decrease/release of mitochondrial cytochrome c were also observed after cantharidin treatment. Flow cytometry-based cell cycle analysis showed a time-dependent accumulation of the sub-G0 population of DL cells, thus, confirming the involvement of apoptosis in tumor cells in cantharidin-mediated antitumor activity. These finding signify that the apoptosis induced by cantharidin in DL cells should involve mitochondrial-dependent pathways. It is suggested that these cantharidin-mediated changes in mitochondria may play a crucial role in its antitumor activity.

Oral bioavailability of cantharidin-loaded solid lipid nanoparticles

BACKGROUND

The clinical application of cantharidin (CA) is limited by its insolubility, toxicity and short half-life in circulation. This study aims to achieve a steady and sustained blood concentration-time profile, using solid lipid nanoparticles (SLNs) as a drug carrier.

METHODS

CA-SLNs were prepared by a film dispersion-ultrasonication method. The physiochemical properties were studied by transmission electron microscopy. In vitro release and in vivo evaluation of CA-SLNs were studied by GC and GC-MS, while a comparison of the pharmacokinetic properties between CA-SLNs and free CA was performed in rats.

RESULTS

The mean size, drug content and encapsulation yield of CA-SLNs were 121 nm, 13.28 ± 0.12% and 93.83 ± 0.45%, respectively. The results show that CA-SLNs had a sustained release profile without a burst effect, a higher bioavailability than free CA after oral administration, and that the relative bioavailability of CA-SLNs to free CA was 250.8%.

CONCLUSION

CA-SLNs could improve the solubility and oral bioavailability of CA.

E4BP4 facilitates glucocorticoid-evoked apoptosis of human leukemic CEM cells via upregulation of Bim

Background

Synthetic GCs serve as therapeutic agents for some lymphoid leukemias because of their ability to induce transcriptional changes via the GC receptor (GR) and trigger apoptosis. Upregulation of the BH3-only member of Bcl-2 family proteins, Bim, has been shown to be essential for GC-evoked apoptosis of leukemic lymphoblasts. Using human T cell leukemic sister clones CEM-C7-14 and CEM-C1-15, we have previously shown that the bZIP transcriptional repressor, E4BP4, is preferentially upregulated by GCs in CEM-C7-14 cells that are susceptible to GC-evoked apoptosis, but not in refractory CEM-C1-15 cells. E4BP4 is an evolutionarily conserved member of the PAR family of bZIP transcription factors related to the C. elegans death specification gene ces2.

Results

Mouse E4BP4 was ectopically expressed in CEM-C1-15 cells, resulting in sensitization to GC-evoked apoptosis in correlation with restoration of E4BP4 and Bim upregulation. shRNA mediated modest knockdown of E4BP4 in CEM-C7-14 cells resulted in concomitant reduction in Bim expression, although GC-evoked fold-induction and sensitivity to apoptosis was similar to parental cells.

Conclusion

Data presented here suggest that GC-mediated upregulation of E4BP4 facilitates Bim upregulation and apoptosis of CEM cells. Since the Bim promoter does not contain any consensus GRE or EBPRE sequences, induction of Bim may be a secondary response.

Transcriptional responses to cantharidin, a protein phosphatase inhibitor, in Arabidopsis thaliana reveal the involvement of multiple signal transduction pathways

Cantharidin is a natural compound isolated from the blister beetle (Epicauta spp.). It is a potent inhibitor of protein serine/threonine phosphatases (PPPs), especially PP2A and PP4. Protein phosphatases and kinases maintain a sensitive balance between dephosphorylated and phosphorylated forms of appropriate proteins, thereby playing important roles in signal transduction pathways and regulation of gene expression, cellular proliferation, cell differentiation, apoptosis and other processes. The foliage of 12-day-old Arabidopsis thaliana seedlings was treated with 200 µM (IC(30) ) of the PPP inhibitor cantharidin, and the entire transcriptome profile was determined by microarray analysis at 2, 10 and 24 h after treatment. The transcription of approximately 10% (2577) of the 24 000 genes of Arabidopsis changed significantly (P≤ 0.05 and signal log ratios: ≥1 or ≤-1) after treatment. Inhibition of PPPs significantly reduced transcription of genes associated with auxin and light signaling and induced expression of genes involved in the hypersensitive response and in flagellin and abscisic acid signaling. The great variety of up- and downregulated genes in this microarray experiment implied that cantharidin interfered with the activities of PPPs that interact directly or indirectly with receptors or are located near the beginning of signal transduction pathways. In many cases, PPPs interact with protein complexes of various receptors such as ethylene or light sensors localized in different cell compartments. They function as negative regulators modifying receptor functions, thus altering signaling that influences transcriptional responses.

Cantharidin modulates development of human monocyte-derived dendritic cells

Cantharidin (CTD), a naturally occurring small molecule isolated from a medicinal insect, possesses anti-cancer and pro-inflammatory properties. We aimed to examine the effect of CTD on human myeloid dendritic cells (DCs) by examining immature DCs differentiated and maturated from CD14+ monocytes. CTD added into a culture of starting CD14+ monocytes markedly and dose-dependently reduced viability of harvested DC. Mature DCs differentiated in the presence of CTD had much fewer, shorter membranous projections than those without CTD. Changes in morphological features characteristic of necrotic cells were also evident. Furthermore, CTD affected DC differentiation and maturation phenotypes including down-regulation of surface CD1a, CD83 and DC-SIGN. DCs derived in the presence of CTD possessed an impaired allostimulatory activity on naive CD4+CD45+RA+T cell in terms of proliferation and interferon-γ production. It suggests that CTD may redirect DC differentiation toward a less mature stage and that this effect is not solely due to its cytotoxicity. Whether this effect refers to immune suppression or tolerance to disease treatments with unwanted immune reactions needs further evaluation.

Cellular responses and expression profiling of human bone marrow stromal cells stimulated with enamel matrix proteins in vitro

OBJECTIVES

The aim of this study was to investigate biological effects and gene expression profiles of enamel matrix proteins (EMPs), on human bone marrow stromal cells (HBMSCs), for preliminary understanding of mechanisms involved in promoting periodontal regeneration by EMPs.

MATERIALS AND METHODS

EMPs were extracted using the acetic acid method, and HBMSCs from human bone marrow aspirates were cultured. Attachment levels, level of cells morphologically attenuated, cell proliferation, alkaline phosphatase (ALP) activity and staining of HBMSCs were measured in the absence and in the presence of EMPs. Microarray analysis was performed to detect gene profiles of HBMSCs by treatment with 200 microg/ml EMPs, for 5 days. Four differential genes were selected for validation of the microarray data using real-time PCR.

RESULTS

EMPs promoted proliferation and ALP activity of HBMSCs in a time- and dose-dependent manner, and at a concentration of 200 microg/ml significantly enhanced proliferation and ALP expression. However, there were no significant changes between EMP-treated groups and the control group in cell attachment and cell process attenuation levels. Twenty-seven genes were differentially expressed by HBMSCs in the presence of EMPs. Expressions of 18 genes were upregulated and expressions of nine genes were found to be downregulated. There was good consistency between data obtained from the validation group and microarray results.

CONCLUSIONS

EMPs promoted cell proliferation and differentiation and gene expression profiles of HBMSCs were affected. This may help elucidation of mechanisms involved in promoting regeneration of periodontal tissues by EMPs.

Progress in the treatment of hepatitis B and digestive tumors with cantharidin and its analogues

Blister beetle or mylabris, pungent in flavor and toxic in nature, has been used for more than 2000 years as traditional Chinese medicine in China. Cantharidin, an active ingredient of the blister beetle, is an effective therapeutic agent against cancers of the liver, breast, esophagus, lung and intestine, etc. However, it is very toxic. Nocantharidin (NCTD), a derivative of cantharidin first synthesized in China, is a new anti-tumor drug with strong anti-tumor activities and increases the number of while blood cells. Cantharidin can be used in the treatment of hepatitis B and pointed condyloma. This paper reviews the progress in its clinical applications at home and abroad.

Molecular biology of cantharidin in cancer cells

Herbal medicine is one of the forms of traditional medical practice. Traditional Chinese medicine (TCM) and traditional Vietnamese medicine (TVM) are well-known for their long-standing tradition of herbal medicine. Secreted by many species of blister beetle, most notably by the 'Spanish fly' (Lytta vesicatoria), cantharidin inhibits protein phosphatases 1 and 2A (PP1, PP2A). Blister beetle has been used in Asian traditional medicine to treat Molluscum contagiosum virus (MCV) infections and associated warts, and is now also used for cancer treatment. A combination of both genomic and postgenomic techniques was used in our studies to identify candidate genes affecting sensitivity or resistance to cantharidin. Cantharidin was not found to be related to multidrug resistance phenotype, suggesting its potential usefulness for the treatment of refractory tumors. Oxidative stress response genes diminish the activity of cantharidin by inducing DNA strand breaks which may be subject to base excision repair and induce apoptosis in a p53- and Bcl2-dependent manner. Cantharidin is one of many natural products used in traditional Chinese medicine and traditional Vietnamese medicine for cancer treatment. Combined methods of pharmaceutical biology and molecular biology can help elucidate modes of action of these natural products.

Expression profiling of ATP-binding cassette transporters in childhood T-cell acute lymphoblastic leukemia

A major issue in the treatment of T-cell acute lymphoblastic leukemia (T-ALL) is resistance to chemotherapeutic drugs. Multidrug resistance can be caused by ATP-binding cassette (ABC) transporters. The majority of these proteins have not yet been examined in T-ALL. Using a newly developed microarray for the simultaneous quantification of 38 ABC transporter genes, we observed a consistent overexpression of ABCA2/ABCA3 in clinical samples of ALL. Therefore, we analyzed the association of these two genes with drug resistance. Treatment of CCRF-CEM and Jurkat cells with methotrexate, vinblastine, or doxorubicin led to an induction of ABCA3 expression, whereas a significant increase of ABCA2 expression was only observed in Jurkat cells. To study the causal relationship of ABCA2/A3 overexpression with drug resistance, we applied RNA interference (RNAi) technology. RNAi specific for ABCA2 or ABCA3 led to a partial decrease of expression in these two ABC transporters. Upon cotreatment of RNAi for ABCA2 with methotrexate and vinblastine, a partial decrease of ABCA2 expression as well as a simultaneous increase of ABCA3 expression was observed. Vice versa, ABCA3 RNAi plus drugs decreased ABCA3 and increased ABCA2 expression. This indicates that down-regulation of one ABC transporter was compensated by the up-regulation of the other. Application of RNAi for both ABCA2 and ABCA3 resulted in a more efficient reduction of the expression of both transporters. As a consequence, a significant sensitization of cells to cytostatic drugs was achieved. In conclusion, ABCA2 and ABCA3 are expressed in many T-ALL and contribute to drug resistance.

Cap1p is involved in multiple pathways of oxidative stress response in Candida albicans

Cap1p, a transcription factor in Candida albicans, is thought to participate in oxidative stress tolerance, but the pathways involved are still unclear. The study was designed to reveal the possible pathways by examining changes in the transcription profile after H2O2 treatment with both the cap1-deleted strain CJD21 and its parental strain CAI4 using microarray analysis. Of the identified 89 genes differentially expressed in CAI4 after exposure to H2O2, 76 genes were in a Cap1p-dependent expression pattern. We have shown that Cap1p is involved in the oxidative stress response in C. albicans via multiple pathways, including the cellular antioxidant defense system (e.g., thioredoxin reductase, glutathione reductase, glutathione S-transferase), carbohydrate metabolism and energy metabolism (e.g., glucose-6-phosphate dehydrogenase, transaldolase, glyoxalase I, NADH-dependent flavin oxidoreductase), protein degradation (e.g., 26S proteasome regulatory subunit, ubiquitin-specific protease), ATP-dependent RNA helicase (e.g., DEAD box protein ATP-dependent RNA helicase), and resistance pathways (e.g., multidrug resistance protein, ABC transporter essential for cadmium resistance). Real-time reverse transcription-PCR analysis further confirmed the results of microarray. Collectively, this study provides new insight into the biological functions of Cap1p in oxidative stress response.

Cellular cIAP2 gene expression associated with anti-HBV activity of TNF-alpha in hepatoblastoma cells

Hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) can abolish HBV gene expression and replication through a noncytopathic mechanism mediated by tumor necrosis factor-alpha (TNF-alpha). However, the molecular mechanisms of TNF-alpha antiviral activity are not completely understood. To examine TNF-alpha-induced cellular responses and identify genes involved in anti-HBV activity, cDNA microarrays dotted with 14, 112 human genes were used to examine the transcriptional changes in HepG2 after treatment with TNF-alpha for 6 h. The results showed that many genes related to ligands and receptors, signal transduction including the TNF-alpha signaling pathway, mitochondrial and ribosomal proteins, and transcription regulation were induced by TNF-alpha. Interestingly, the TNF-alpha-inducible gene cIAP2 was found to inhibit HBV protein synthesis, viral replication, and transcription. Taken together, our results revealed the global effects of TNF-alpha treatment on hepatocellular gene expression. The antiviral genes identified by microarray could be developed as potential new anti-HBV drugs or for other novel therapies.

Characterization of human LNX, a novel ligand of Numb protein X that is downregulated in human gliomas

Gliomas are major tumors of the central nervous system with a wide spectrum of different tumor types. Ligand of Numb protein X (LNX) is PDZ domain containing protein that interacts with cell fate determinant Numb. cDNA microarray analysis was used to determine the expression of 13,939 genes in a set of 18 gliomas. It showed that human LNX was downregulated in 100% of gliomas including low- and high-grade ones, which was confirmed by Northern blot. In situ hybridization analysis revealed that LNX was lowly expressed in cytoplasm of glioma cells. Thus, LNX might act as a diagnostic marker and a potential therapeutic target for glioma. Two-hybrid screen in yeast was used to identify human LNX interacting proteins important for LNX function. It showed that human LNX interacted with Ski interacting protein (SKIP) via PDZ domains. The co-immunoprecipitation results suggested that LNX interacted with SKIP in HEK293 cells. LNX could affect the subcellular localization of Numb, which indicated that LNX might function as a molecular anchor that localized Numb to the subcellular site of its interaction with Notch. The presence of multiple protein binding domains involved in signal transduction and interaction with Numb and SKIP suggested an important role for LNX in tumorogenesis.

Molecular modes of action of cantharidin in tumor cells

Cancer chemotherapy is often limited by patient's toxicity and tumor drug resistance indicating that new drug development and modification of existing drugs is critical for improving the therapeutic response. Traditional Chinese medicine is a rich source of potential anticancer agents. In particular, cantharidin (CAN), the active principle ingredient from the blister beetle, Mylabris, has anti-tumor activity, but the cytotoxic mechanism is unknown. In leukemia cells, cantharidin induces apoptosis by a p53-dependent mechanism. Cantharidin causes both DNA single- and double-strand breaks. Colony-forming assays with knockout and transfectant cells lines showed that DNA polymerase beta, but not ERCC1, conferred increased cell survival after cantharidin treatment, indicating that base excision repair (BER), rather than nucleotide excision repair (NER), is important for CAN-induced DNA lesions. Oxidative stress-resistant thymic lymphoma-derived WEHI7.2 variants are also more resistant to cantharidin. These data suggest that cantharidin treatment causes oxidative stress that provokes DNA damage and p53-dependent apoptosis.

Classification between normal and tumor tissues based on the pair-wise gene expression ratio

Background

Precise classification of cancer types is critically important for early cancer diagnosis and treatment. Numerous efforts have been made to use gene expression profiles to improve precision of tumor classification. However, reliable cancer-related signals are generally lacking.

Method

Using recent datasets on colon and prostate cancer, a data transformation procedure from single gene expression to pair-wise gene expression ratio is proposed. Making use of the internal consistency of each expression profiling dataset this transformation improves the signal to noise ratio of the dataset and uncovers new relevant cancer-related signals (features). The efficiency in using the transformed dataset to perform normal/tumor classification was investigated using feature partitioning with informative features (gene annotation) as discriminating axes (single gene expression or pair-wise gene expression ratio). Classification results were compared to the original datasets for up to 10-feature model classifiers.

Results

82 and 262 genes that have high correlation to tissue phenotype were selected from the colon and prostate datasets respectively. Remarkably, data transformation of the highly noisy expression data successfully led to lower the coefficient of variation (CV) for the within-class samples as well as improved the correlation with tissue phenotypes. The transformed dataset exhibited lower CV when compared to that of single gene expression. In the colon cancer set, the minimum CV decreased from 45.3% to 16.5%. In prostate cancer, comparable CV was achieved with and without transformation. This improvement in CV, coupled with the improved correlation between the pair-wise gene expression ratio and tissue phenotypes, yielded higher classification efficiency, especially with the colon dataset – from 87.1% to 93.5%. Over 90% of the top ten discriminating axes in both datasets showed significant improvement after data transformation. The high classification efficiency achieved suggested that there exist some cancer-related signals in the form of pair-wise gene expression ratio.

Conclusion

The results from this study indicated that: 1) in the case when the pair-wise expression ratio transformation achieves lower CV and higher correlation to tissue phenotypes, a better classification of tissue type will follow. 2) the comparable classification accuracy achieved after data transformation suggested that pair-wise gene expression ratio between some pairs of genes can identify reliable markers for cancer.