Involvement of mitochondrial pathway in NCTD-induced cytotoxicity in human hepG2 cells

Advancements in nano drug delivery system for liver cancer therapy based on mitochondria-targeting

Based on poor efficacy and non-specific toxic side effects of conventional drug therapy for liver cancer, nano-based drug delivery system (NDDS) offers the advantage of drug targeting delivery. Subcellular targeting of nanomedicines on this basis enables more precise and effective termination of tumor cells. Mitochondria, as the crucial cell powerhouse, possesses distinctive physical and chemical properties in hepatoma cells different from that in hepatic cells, and controls apoptosis, tumor metastasis, and cellular drug resistance in hepatoma cells through metabolism and dynamics, which serves as a good choice for drug targeting delivery. Thus, mitochondria-targeting NDDS have become a recent research focus, showcasing the design of cationic nanoparticles, metal nanoparticles, mitochondrial peptide modification and so on. Although many studies have shown good results regarding anti-tumor efficacy, it is a long way to go before the successful translation of clinical application. Based on these, we summarized the specificity and importance of mitochondria in hepatoma cells, and reviewed the current mitochondria-targeting NDDS for liver cancer therapy, aiming to provide a better understanding for current development process, strengths and weaknesses of mitochondria-targeting NDDS as well as informing subsequent improvements and developments.

Animal-derived natural products for hepatocellular carcinoma therapy: current evidence and future perspectives

Hepatocellular carcinoma (HCC) has a high morbidity and mortality rate, and the survival rate of HCC patients remains low. Animal medicines have been used as potential therapeutic tools throughout the long history due to their different structures of biologically active substances with high affinity to the human body. Here, we focus on the effects and the mechanism of action of animal-derived natural products against HCC, which were searched in databases encompassing Web of Science, PubMed, Embase, Science Direct, Springer Link, and EBSCO. A total of 24 natural products from 12 animals were summarized. Our study found that these natural products have potent anti-hepatocellular carcinoma effects. The mechanism of action involving apoptosis induction, autophagy induction, anti-proliferation, anti-migration, and anti-drug resistance via phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), Ras/extracellular signal regulated kinases (ERK)/mitogen-activated protein kinase (MAPK), Wnt/β-catenin, and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways. Huachansu injection and sodium cantharidate have been used in clinical applications with good efficacy. We review the potential of animal-derived natural products and their derivatives in the treatment of HCC to date and summarize their application prospect and toxic side effects, hoping to provide a reference for drug development for HCC.

Norcantharidin Enhances the Antitumor Effect of 5-Fluorouracil by Inducing Apoptosis of Cervical Cancer Cells: Network Pharmacology, Molecular Docking, and Experimental Validation

The high recurrence rate of cervical cancer is a leading cause of cancer deaths in women. 5-Fluorouracil (5-FU) is an antitumor drug used to treat many types of cancer, but its diminishing effectiveness and side effects limit its use. Norcantharidin (NCTD), a demethylated derivative of cantharidin, exhibits various biological activities. Here, we investigated whether NCTD could potentiate 5-FU to induce cervical cancer cell death. To assess the cell viability and synergistic effects of the drugs, cell counting kit-8 and colony formation assays were performed using HR-HPV-positive cervical cancer cell lines. Annexin V-FITC/PI staining and TUNEL assays were performed to confirm the induction of apoptosis. The synergistic effect of NCTD on the antitumor activity of 5-FU was analyzed using network pharmacology, molecular docking, and molecular dynamics simulations. Apoptosis-related proteins were examined using immunoblotting. The combination of NCTD and 5-FU was synergistic in cervical cancer cell lines. Network pharmacological analysis identified 10 common targets of NCTD and 5-FU for cervical cancer treatment. Molecular docking showed the strong binding affinity of both compounds with CA12, CASP9, and PTGS1. Molecular dynamics simulations showed that the complex system of both drugs with caspase-9 could be in a stable state. NCTD enhanced 5-FU-mediated cytotoxicity by activating apoptosis-related proteins. NCTD acts synergistically with 5-FU to inhibit cervical cancer cell proliferation. NCTD enhances 5-FU-induced apoptosis in cervical cancer cell lines via the caspase-dependent pathway.

Tea and Citrus maxima complex induces apoptosis of human liver cancer cells via PI3K/AKT/mTOR pathway in vitro

Objective

In this study, black tea and Citrus maxima (BT-CM), yellow tea and C. maxima (YT-CM), green tea and C. maxima (GT-CM) as subjects, the active ingredient content and antioxidant activity of three tea and C. maxima (T-CM) were analyzed. The effects of three T-CMs on apoptosis of liver cells in vitro and its mechanism were further explored.

Methods

National standard method and HPLC were used for active ingredient analysis. MTT, cell flow cytometry and Western blot were used to analyze the effects of three T-CMs on cell proliferation, apoptosis, and its underlying molecular mechanism.

Results

The content of tea polyphenols, free amino acids, ratio of polyphenols and amino acids, ester catechins, non-ester catechins and caffeine in YT-CM and GT-CM was significantly higher than that of BT-CM. The in vitro antioxidant capacity of YT-CM and GT-CM was also significantly stronger than that of BT-CM. Three T-CMs had the effects of inhibiting proliferation, arresting cell cycle and inducing apoptosis in HepG2 and Bel7402 cells, especially YT-CM and GT-CM. Western blot analysis showed three T-CMs activated PI3K/AKT/mTOR signaling pathway and regulated the expression levels of apoptosis-related proteins Bax, Bcl-2 and Caspase-3/9. YT-CM and GT-CM had better ability to change the signal pathway than BT-CM.

Conclusion

In short, T-CMs, which combined different degrees of fermentation tea with C. maxima, were rich in nutrients and biologically active substances. T-CMs, especially YT-CM and GT-CM, are healthy drinks that help to prevent and treat liver cancer.

Grape Seed Proanthocyanidins play the roles of radioprotection on Normal Lung and radiosensitization on Lung Cancer via differential regulation of the MAPK Signaling Pathway

Radiation-induced lung injury (RILI) is a common serious complication and dose-limiting factor caused by radiotherapy for lung cancer. This study was to investigate radioprotective effects of grape seed proanthocyanidins (GSP) on normal lung as well as radiosensitizing effects on lung cancer. In vitro, we demonstrated radioprotective effects of GSP on normal alveolar epithelial cells (MLE-12 and BEAS/2B) and radiosensitizing effects on lung cancer cells (LLC and A549). In vivo, we confirmed these two-way effects in tumor-bearing mice. The results showed that GSP inhibited tumor growth, and played a synergistic killing effect with radiotherapy on lung cancer. Meanwhile, GSP reduced radiation damage to normal lung tissues. The two-way effects related to the differential regulation of the MAPK signaling pathway by GSP on normal lung and lung cancer. Moreover, GSP regulated secretion of cytokines IL-6 and IFN-γ and expression of p53 and Ki67 on normal lung and lung cancer. Our findings suggest that GSP is expected to be an ideal radioprotective drug for lung cancer patients who are treated with radiotherapy.

NCTD elicits proapoptotic and antiglycolytic effects on colorectal cancer cells via modulation of Fam46c expression and inhibition of ERK1/2 signaling

Colorectal cancer is a digestive tract malignancy and the third leading cause of cancer‑related mortality worldwide. Norcantharidin (NCTD), the demethylated form of cantharidin, has been reported to possess anticancer properties. Family‑with‑sequence‑similarity‑46c (Fam46c), a non‑canonical poly(A) polymerase, has been reported to be critical in NCTD‑mediated effects in numerous types of cancer, including hepatoma. In the current study, it was found that Fam46c expression was reduced in colorectal cancer tissues and cells. Treatment with NCTD was observed to significantly enhance apoptosis and inhibit glycolysis in colorectal cancer cells. In addition, Fam46c and cleaved caspase 3 expression levels were found to be increased in response to NCTD treatment, in contrast to tumor‑specific pyruvate kinase M2 and phosphorylated ERK expression, which was reduced. Importantly, overexpression of Fam46c exerted similar effects as NCTD treatment on the apoptosis and glycolysis of colorectal cancer cells, whereas Fam46c knockdown strongly attenuated the effect of NCTD. Moreover, epidermal growth factor, which acts as an agonist of ERK1/2 signaling, weakened the effects of NCTD on colorectal cancer cells. Taken together, the results indicated that NCTD promotes apoptosis and suppresses glycolysis in colorectal cancer cells by possibly targeting Fam46c and inhibiting ERK1/2 signaling, hence suggesting that Fam46c may act as a tumor suppressor in colorectal cancer. Thus, the present study identified a novel therapeutic target of NCTD in the clinical treatment of colorectal cancer.

Insight into norcantharidin, a small-molecule synthetic compound with potential multi-target anticancer activities

Norcantharidin (NCTD) is a demethylated derivative of cantharidin, which is an anticancer active ingredient of traditional Chinese medicine, and is currently used clinically as a routine anti-cancer drug in China. Clarifying the anticancer effect and molecular mechanism of NCTD is critical for its clinical application. Here, we summarized the physiological, chemical, pharmacokinetic characteristics and clinical applications of NCTD. Besides, we mainly focus on its potential multi-target anticancer activities and underlying mechanisms, and discuss the problems existing in clinical application and scientific research of NCTD, so as to provide a potential anticancer therapeutic agent for human malignant tumors.

Targeting Reactive Oxygen Species in Cancer via Chinese Herbal Medicine

Recently, reactive oxygen species (ROS), a class of highly bioactive molecules, have been extensively studied in cancers. Cancer cells typically exhibit higher levels of basal ROS than normal cells, primarily due to their increased metabolism, oncogene activation, and mitochondrial dysfunction. This moderate increase in ROS levels facilitates cancer initiation, development, and progression; however, excessive ROS concentrations can lead to various types of cell death. Therefore, therapeutic strategies that either increase intracellular ROS to toxic levels or, conversely, decrease the levels of ROS may be effective in treating cancers via ROS regulation. Chinese herbal medicine (CHM) is a major type of natural medicine and has greatly contributed to human health. CHMs have been increasingly used for adjuvant clinical treatment of tumors. Although their mechanism of action is unclear, CHMs can execute a variety of anticancer effects by regulating intracellular ROS. In this review, we summarize the dual roles of ROS in cancers, present a comprehensive analysis of and update the role of CHM—especially its active compounds and ingredients—in the prevention and treatment of cancers via ROS regulation and emphasize precautions and strategies for the use of CHM in future research and clinical trials.

FCY-302, a Novel Small Molecule, Induces Apoptosis in Leukemia and Myeloma Cells by Attenuating Key Antioxidant and Mitochondrial Enzymes

Arylidene analogs are well proven for biological activities. FCY-302, a novel small molecule belonging to this class, was screened for its biological efficacy in leukemia and myeloma cells. FCY-302 selectively inhibited proliferation of cancer cells with GI₅₀ values of 395.2 nM, 514.6 Nm, and 642.4 nM in HL-60, Jurkat, and RPMI-8226 cells, respectively. The compound also increased sub-G₀ peak in the cancer cell cycle and favored apoptosis determined by annexin V assay. The compound decreased the antiapoptotic Bcl-2 levels and increased proapoptotic Bax proteins in leukemia and myeloma cell lines. FCY-302 attenuated the mitochondrial membrane-bound Na⁺/K⁺ ATPase, Ca²⁺ ATPase, and Mg²⁺ ATPase enzyme activities and significantly decreased activities of antioxidant enzymes like SOD, CAT, G_R, and GST in all the three cancer cells tested. Our findings suggest that FCY-302 inhibits the proliferation of leukemia and myeloma cancer cells by altering key mitochondrial and antioxidant enzymes, eventually driving them to apoptosis. These results drive focus on FCY-302 and its analogs to be developed as potential small molecules with bioactivities against cancer.

Norcantharidin induce apoptosis in human nasopharyngeal carcinoma through caspase and mitochondrial pathway

While Nasopharyngeal carcinoma (NPC) is uncommon in western countries, it is endemic in Southeast Asia and Southern China. Previous study of norcantharidin (NCTD), isolated from blister beetles, has proved its anticancer effect on various tumors. However, the effect of NCTD in NPC has never been studied. The purpose of this study is to inspect the suppression activity of NCTD on NPC, along with the underlying mechanism. NPC cell line NPC-BM was treated with NCTD. NCTD remarkably inhibited proliferation and induce apoptosis in NPC-BM cell. Activation of caspase-3, -8, -9 was observed through western blotting. The expression of antiapoptotic protein Bcl-XL was significantly reduced, but expression of proapoptotic protein Bak was increased after treatment of NCTD. The cytotoxic effect of NCTD on NPC-BM cell is mainly due to apoptosis, mediated by caspase and mitochondrial pathway. These results suggested that NCTD could be a potential anticancer agent for NPC.

Dihydroartemisinin Exerts Anti-Tumor Activity by Inducing Mitochondrion and Endoplasmic Reticulum Apoptosis and Autophagic Cell Death in Human Glioblastoma Cells

Glioblastoma (GBM) is the most advanced and aggressive form of gliomas. Dihydroartemisinin (DHA) has been shown to exhibit anti-tumor activity in various cancer cells. However, the effect and molecular mechanisms underlying its anti-tumor activity in human GBM cells remain to be elucidated. Our results proved that DHA treatment significantly reduced cell viability in a dose- and time-dependent manner by CCK-8 assay. Further investigation identified that the cell viability was rescued by pretreatment either with Z-VAD-FMK, 3-methyladenine (3-MA) or in combination. Moreover, DHA induced apoptosis of GBM cells through mitochondrial membrane depolarization, release of cytochrome c and activation of caspases-9. Enhanced expression of GRP78, CHOP and eIF2α and activation of caspase 12 were additionally confirmed that endoplasmic reticulum (ER) stress pathway of apoptosis was involved in the cytotoxicity of DHA. DHA-treated GBM cells exhibited the morphological and biochemical changes typical of autophagy. Co-treatment with chloroquine (CQ) significantly induced the above effects. Furthermore, ER stress and mitochondrial dysfunction were involved in the DHA-induced autophagy. Further study revealed that accumulation of reactive oxygen species (ROS) was attributed to the DHA induction of apoptosis and autophagy. The illustration of these molecular mechanisms will present a novel insight for the treatment of human GBM.

Mechanisms of inhibiting human leukemia cell lines by serum of rats treated with compound banmao capsule

Compound banmao capsule (CBC) is a traditional Chinese medicinal formula composed of extracts from 11 organisms. The present study investigated the mechanism of CBC on the biological behavior of human leukemia cell lines using seropharmacological methods. CBC-containing rat serum was prepared by intragastrical administration of CBC to rats. The proliferation of human leukemia HL60 and K562 cell lines was assayed by measuring cell viability with the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium method, while cell cycle distribution and the rate of apoptosis were evaluated with flow cytometry. The mRNA expression of vascular endothelial growth factor A (VEGF-A) and chemotactic and inflammatory genes in human leukemia cell lines was examined using reverse transcription quantitative-polymerase chain reaction methods. It was revealed that the proliferation of K562 and HL60 cells was significantly inhibited by the CBC-containing rat serum at 72 h. The CBC-containing serum also promoted the apoptosis of K562 and HL60 cell lines. The CBC-containing serum altered the cell cycle progression of K562 and HL60, increasing the proportion of the cells in G1 phase and decreasing the proportion of the cells in S phase. Attenuated expression of VEGF-A and a decreasing trend in the expression of chemotactic and inflammatory genes were identified following treatment with CBC-containing serum in HL60 and K562 cells. In conclusion, CBC-containing serum exerted an inhibitory effect on the growth of K562 and HL60 cells by decreasing cellular proliferation, promoting apoptosis and cell cycle arrest, and decreasing the expression of VEGF-A, and chemotactic and inflammatory genes.

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.

An indolylquinoline derivative promotes apoptosis in human lung cancer cells by impairing mitochondrial functions

A number of effective anti-cancer drugs contain either indole or quinoline group. Compounds fused indole and quinoline moieties altogether as indolylquinoline were rarely reported as anti-cancer agents. We reported here that a synthetic indolylquinoline derivative, 3-((7-ethyl-1H-indol-3-yl)-methyl)-2-methylquinoline (EMMQ), inhibited the growth of human non-small cell lung cancer (NSCLC) cells in dose- and time-dependent manners. The cytotoxicity was mediated through apoptotic cell death that began with mitochondrial membrane potential interruption and DNA damage. EMMQ caused transient elevation of p53 that assists in cytochrome c release, cleavage of downstream PARP and procaspase-3 and mitochondria-related apoptosis. The degree of apoptotic cell death depends on the status of tumor suppressor p53 of the target cells. H1299 cells with stable ectopic expression of p53 induced cytotoxicity by disrupting mitochondria functions that differed with those transfected with mutant p53. Knocking-down of p53 attenuated drug effects. EMMQ suppressed the growth of A549 tumor cells in xenograft tumors by exhibiting apoptosis characteristics. Given its small molecular weight acting as an effective p53 regulator in NSCLC cells, EMMQ could be an addition to the current list of lung cancer treatment.

Preventive and Therapeutic Effects of Chinese Herbal Compounds against Hepatocellular Carcinoma

Traditional Chinese Medicines, unique biomedical and pharmaceutical resources, have been widely used for hepatocellular carcinoma (HCC) prevention and treatment. Accumulated Chinese herb-derived compounds with significant anti-cancer effects against HCC have been identified. Chinese herbal compounds are effective in preventing carcinogenesis, inhibiting cell proliferation, arresting cell cycle, inducing apoptosis, autophagy, cell senescence and anoikis, inhibiting epithelial-mesenchymal transition, metastasis and angiogenesis, regulating immune function, reversing drug resistance and enhancing the effects of chemotherapy in HCC. This paper comprehensively reviews these compounds and their effects on HCC. Finally, the perspectives and rational application of herbal compounds for HCC management are discussed.

In vitro evaluation of anticancer and biological activities of synthesized manganese oxide nanoparticles

This paper presents the results from a systematic study into the characterization and anticancer and biological activity of synthesized super-paramagnetic manganese oxide nanoparticles (Mn₃O₄-NPs).

Evaluation of DNA damage induced by norcantharidin in human cultured lymphocytes

Norcantharidin (NCTD) is currently used in the treatment of several cancers such as leukemia, melanoma and hepatoma. The mechanism of action of NCTD is suggested to involve induction of apoptosis of cancer cells via production of reactive oxygen species. In this study, the genotoxic effect of different concentrations of NCTD (1, 10 and 20 μm) in human lymphocytes was investigated using sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) assays. The results revealed that NCTD significantly increased the rate of SCEs (p < 0.05) in a dose-dependent manner. In addition, NCTD significantly increased the number of high-frequency cells (SCEs ≥ 8, p < 0.05). However, NCTD did not have any significant effect on the rate of CAs (p > 0.05). In addition, no significant differences were detected in the mitotic index or proliferative index at examined doses (up to 20 μm). In conclusion, NCTD is genotoxic to human cultured lymphocytes as measured by SCE assay.

Induction of Suicidal Erythrocyte Death by Cantharidin

The natural phosphoprotein phosphatase inhibitor cantharidin, primarily used for topical treatment of warts, has later been shown to trigger tumor cell apoptosis and is thus considered for the treatment of malignancy. Similar to apoptosis of tumor cells, erythrocytes may undergo eryptosis, a suicidal cell death characterized by cell shrinkage and translocation of cell membrane phosphatidylserine to the erythrocyte surface. Signaling of eryptosis includes increase of cytosolic Ca²⁺-activity ([Ca²⁺]_i), ceramide, oxidative stress and dysregulation of several kinases. Phosphatidylserine abundance at the erythrocyte surface was quantified utilizing annexin-V-binding, cell volume from forward scatter, [Ca²⁺]_i from Fluo3-fluorescence, ceramide from antibody binding, and reactive oxidant species (ROS) from 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence. A 48 h treatment of human erythrocytes with cantharidin significantly increased the percentage of annexin-V-binding cells (≥10 μg/mL), significantly decreased forward scatter (≥25 μg/mL), significantly increased [Ca²⁺]_i (≥25 μg/mL), but did not significantly modify ceramide abundance or ROS. The up-regulation of annexin-V-binding following cantharidin treatment was not significantly blunted by removal of extracellular Ca²⁺ but was abolished by kinase inhibitor staurosporine (1 μM) and slightly decreased by p38 inhibitor skepinone (2 μM). Exposure of erythrocytes to cantharidin triggers suicidal erythrocyte death with erythrocyte shrinkage and erythrocyte membrane scrambling, an effect sensitive to kinase inhibitors staurosporine and skepinone.

Atg5 siRNA inhibits autophagy and enhances norcantharidin-induced apoptosis in hepatocellular carcinoma

Cantharidin is a terpenoid isolated from Chinese blister beetles, and norcantharidin (NCTD) is a demethylated analog of cantharidin. It has been reported that cantharidin and norcantharidin have anticancer activities. Growing evidence suggests that inhibiting autophagy can induce apoptosis in the human hepatoma cell line HepG2. The objective of the present study was to determine whether inhibition of autophagy enhances NCTD-induced apoptosis in HepG2 cells. HepG2 cells were cultured in DMEM containing NCTD. Autophagy was upregulated in the presence of HBSS media supplemented with Ca2+ and Mg2+ and 10 mM HEPES and downregulated in the presence of 3-methyladenine (3-MA) and Atg5 siRNA. Autophagy, cell viability, and the expression of apoptotic proteins were assessed in HepG2 cells. Our data showed that cell apoptosis generally increased after norcantharidin treatment in HepG2 cells. Expression of LC3-II, an autophagosome marker, increased when cells were treated with HBSS media. It also increased cell viability. However, in the presence of 3-MA and Atg5 siRNA, autophagy was inhibited, LC3-II expression decreased and cell apoptosis increased. There was increased expression of Bax, cytochrome c, cleaved caspase-3, caspase-9 and PARP and the mitochondrial membrane potential was disrupted. Additionally, increased apoptosis was accompanied by increased reactive oxygen species (ROS) production. NCTD has anticancer activity, and Atg5 siRNA-mediated downregulation of autophagy enhanced its anticancer actions due to ROS generation and activation of the mitochondrial apoptosis pathway.

Traditional Chinese medicine for prevention and treatment of hepatocarcinoma: From bench to bedside

Traditional Chinese medicine (TCM) has played a positive role in the management of hepatocarcinoma. Hepatocarcinoma patients may present Qi-stagnation, damp-heat, blood stasis, Qi-deficiency, Yin-deficiency and other TCM syndromes (Zheng). Modern treatments such as surgery, transarterial chemoembolization (TACE) and high intensity focus ultrasound treatment would influence the manifestation of TCM syndromes. Herbs with traditional efficacy of tonifying Qi, blood and Yin, soothing liver-Qi stagnation, clearing heat and detoxifying and dissolving stasis, have been demonstrated to be potent to prevent hepatocarcinogenesis. TCM has been widely used in all aspects of integrative therapy in hepatocarcinoma, including surgical resection, liver transplantation, TACE, local ablative therapies and even as monotherapy for middle-advanced stage hepatocarcinoma. Clinical practices have confirmed that TCM is effective to alleviate clinical symptoms, improve quality of life and immune function, prevent recurrence and metastasis, delay tumor progression, and prolong survival time in hepatocarcinoma patients. The effective mechanism of TCM against hepatocarcinoma is related to inducing apoptosis, autophagy, anoikis and cell senescence, arresting cell cycle, regulating immune function, inhibiting metastasis and angiogenesis, reversing drug resistance and enhancing effects of chemotherapy. Along with the progress of research in this field, TCM will contribute more to the prevention and treatment of hepatocarcinoma.

cDNA microarray analysis of the effect of cantharidin on DNA damage, cell cycle and apoptosis-associated gene expression in NCI-H460 human lung cancer cells in vitro

Cantharidin (CTD) induces cytotoxic effects in different types of human cancer cell; however, to date, there have been no studies on the effects of CTD on gene expression in human lung cancer cells and the potential associated signaling pathways. Therefore, the present study aimed to investigate how CTD affects the expression of key genes and functional pathways of human H460 lung cancer cells using complementary DNA microarray analysis. Human H460 lung cancer cells were cultured for 24 h in the presence or absence of 10 µM CTD; gene expression was then examined using microarray analysis. The results indicated that 8 genes were upregulated > 4-fold, 29 genes were upregulated >3-4-fold and 156 genes were upregulated >2-3-fold. In addition, 1 gene was downregulated >4 fold, 14 genes were downregulated >3-4-fold and 150 genes were downregulated >2-3 fold in H460 cells following exposure to CTD. It was found that CTD affected DNA damage genes, including DNIT3 and GADD45A, which were upregulated 2.26- and 2.60-fold, respectively, as well as DdiT4, which was downregulated 3.14-fold. In addition, the expression of genes associated with the cell cycle progression were altered, including CCND2, CDKL3 and RASA4, which were upregulated 2.72-, 2.19- and 2.72-fold, respectively; however, CDC42EP3 was downregulated 2.16-fold. Furthermore, apoptosis-associated genes were differentially expressed, including CARD6, which was upregulated 3.54-fold. In conclusion, the present study demonstrated that CTD affected the expression of genes associated with DNA damage, cell cycle progression and apoptotic cell death in human lung cancer H460 cells.

Biogenic metal nanoformulations induce Bax/Bcl2 and caspase mediated mitochondrial dysfunction in human breast cancer cells (MCF 7)

Green synthesized metal NPs can potentially inhibit the proliferation of MCF-7 cells and trigger apoptosis through Bax/Bcl2 and caspase–cascade mediated mitochondrial dysfunction.

Dual effect of oxidative stress on leukemia cancer induction and treatment

Oxidative stress (OS) has been characterized by an imbalance between the production of reactive oxygen species (ROS) and a biological system's ability to repair oxidative damage or to neutralize the reactive intermediates including peroxides and free radicals. High ROS production has been associated with significant decrease in antioxidant defense mechanisms leading to protein, lipid and DNA damage and subsequent disruption of cellular functions. In humans, OS has been reported to play a role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Lou Gehrig's disease, multiple sclerosis and Parkinson's disease, as well as atherosclerosis, autism, cancer, heart failure, and myocardial infarction. Although OS has been linked to the etiology and development of chronic diseases, many chemotherapeutic drugs have been shown to exert their biologic activity through induction of OS in affected cells. This review highlights the controversial role of OS in the development and progression of leukemia cancer and the therapeutic application of increased OS and antioxidant approaches to the treatment of leukemia patients.

Design, synthesis and 3D-QSAR studies of new diphenylamine containing 1,2,4-triazoles as potential antitubercular agents

A new series of new diphenylamine containing 1,2,4-triazoles were synthesized from 4-arylideneamino-5-[2-(2,6-dichlorophenylamino) benzyl]-2H-1,2,4-triazole-3(4H)-thiones 3a-f. The synthesized compounds were screened for in-vitro antimycobacterial and antibacterial activities. The synthesized compounds 4a, 4e and 4d have shown potential activity against Mycobacterium tuberculosis H37Rv strain with MIC of 0.2, 1.6 and 3.125 μM respectively. To investigate the SAR of diphenylamine containing 1,2,4-triazole derivatives in more details, CoMFA (q(2)-0.432, r(2)-0.902) and CoMSIA (q(2)-0.511, r(2)-0.953) models on M. tuberculosis H37Rv were established. The generated 3D-QSAR models are externally validated and have shown significant statistical results, and these models can be used for further rational design of novel diphenylamine containing 1,2,4-triazoles as potent antitubercular agents.

Norcantharidin induces growth inhibition and apoptosis of glioma cells by blocking the Raf/MEK/ERK pathway

Background

Malignant gliomas represent the most common primary brain tumors. The prognosis of patients with malignant gliomas is poor in spite of current intensive therapy and novel therapeutic modalities are needed. Here we report that norcantharidin is effective in growth inhibition of glioma cell lines in vitro.

Methods

Glioma cell lines (U87 and C6) were treated with norcantharidin. The effects of norcantharidin on the proliferation and apoptosis of glioma cells were measured by 3-[4,5-dimethylthiazol-2-thiazolyl]-2,5-diphenyl-tetrazolium bromide (MTT) assay and flow cytometry. Western blotting was employed to determine the signaling pathway changes.

Results

The results showed that norcantharidin effectively inhibited cell growth and induced apoptosis in glioma cells, which was concurrent with inhibition of the expression of phospho-MEK and phospho-ERK. Furthermore, the expression anti-apoptotic proteins Bcl-2 and Mcl-1 significantly reduced, but no changes in Bcl-xL and Bax.

Conclusions

Our findings demonstrate that norcantharidin is effective for growth inhibition of glioma cell lines and suggest that norcantharidin may be a new therapeutic option for patients with glioma.

Synthesis of novel lipophilic N-substituted norcantharimide derivatives and evaluation of their anticancer activities

This research attempted to study the effect of lipophilicity on the anticancer activity of N-substituted norcantharimide derivatives. Twenty-three compounds were synthesized and their cytotoxicities against five human cancer cell lines studied. The lipophilicity of each derivative was altered by its substituent, an alkyl, alkyloxy, terpenyl or terpenyloxy group at the N-position of norcantharimide. Further, among all synthesized derivatives studied, the compounds N-farnesyloxy-7-oxabicyclo[2.2.1]heptane-2,3-dicarboximide (9), and N-farnesyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboximide (18), have shown the highest cytotoxicity, anti-proliferative and apoptotic effect against human liver carcinoma HepG2 cell lines, yet displayed no significant cytotoxic effect on normal murine embryonic liver BNL CL.2 cells. Their overall performance led us to believe that these two compounds might be potential candidates for anticancer drugs development.

Inhibition of tumor vasculogenic mimicry and prolongation of host survival in highly aggressive gallbladder cancers by norcantharidin via blocking the ephrin type a receptor 2/focal adhesion kinase/paxillin signaling pathway

Vasculogenic mimicry (VM) is a newly-defined tumor microcirculation pattern in highly aggressive malignant tumors. We recently reported tumor growth and VM formation of gallbladder cancers through the contribution of the ephrin type a receptor 2 (EphA2)/focal adhesion kinase (FAK)/Paxillin signaling pathways. In this study, we further investigated the anti-VM activity of norcantharidin (NCTD) as a VM inhibitor for gallbladder cancers and the underlying mechanisms. In vivo and in vitro experiments to determine the effects of NCTD on tumor growth, host survival, VM formation of GBC-SD nude mouse xenografts, and vasculogenic-like networks, malignant phenotypes i.e., proliferation, apoptosis, invasion and migration of GBC-SD cells. Expression of VM signaling-related markers EphA2, FAK and Paxillin in vivo and in vitro were examined by immunofluorescence, western blotting and real-time polymerase chain reaction (RT-PCR), respectively. The results showed that after treatment with NCTD, GBC-SD cells were unable to form VM structures when injecting into nude mouse, growth of the xenograft was inhibited and these observations were confirmed by facts that VM formation by three-dimensional (3-D) matrix, proliferation, apoptosis, invasion, migration of GBC-SD cells were affected; and survival time of the xenograft mice was prolonged. Furthermore, expression of EphA2, FAK and Paxillin proteins/mRNAs of the xenografts was downregulated. Thus, we concluded that NCTD has potential anti-VM activity against human gallbladder cancers; one of the underlying mechanisms may be via blocking the EphA2/FAK/Paxillin signaling pathway.

Norcantharidin induced DU145 cell apoptosis through ROS-mediated mitochondrial dysfunction and energy depletion

Norcantharidin (NCTD), a demethylated analog of cantharidin derived from blister beetles, has attracted considerable attentions in recent years due to their definitely toxic properties and the noteworthy advantages in stimulating bone marrow and increasing the peripheral leukocytes. Hence, it is worth studying the anti-tumor effect of NCTD on human prostate cancer cells DU145. It was found that after the treatment of NCTD with different concentrations (25-100 μM), the cell proliferation was significantly inhibited, which led to the appearance of micronucleus (MN). Moreover, the cells could be killed in a dose-/ time-dependent manner along with the reduction of PCNA (proliferating cell nuclear antigen) expression, destruction of mitochondrial membrane potential (MMP), down-regulation of MnSOD, induction of ROS, depletion of ATP, and activation of AMPK (Adenosine 5‘-monophosphate -activated protein kinase) . In addition, a remarkable release of cytochrome c was found in the cells exposed to 100 μM NCTD and exogenous SOD-PEG could eliminate the generation of NCTD-induced MN. In conclusion, our studies indicated that NCTD could induce the collapse of MMP and mitochondria dysfunction. Accumulation of intercellular ROS could eventually switch on the apoptotic pathway by causing DNA damage and depleting ATP.

Applications of flow cytometry to toxicological mycotoxin effects in cultured mammalian cells: a review

This review gives an overview of flow cytometry applications to toxicological studies of several physiological target sites of mycotoxins on different mammalian cell lines. Mycotoxins are secondary metabolites of fungi that may be present in food, feed, air and water. The increasing presence of mycotoxins in crops, their wide distribution in the food chain, and their potential for toxicity demonstrate the need for further knowledge. Flow cytometry has become a valuable tool in mycotoxin studies in recent years for the rapid analysis of single cells in a mixture. In toxicology, the power of these methods lies in the possibility of determining a wide range of cell parameters, providing valuable information to elucidate cell growth and viability, metabolic activity, mitochondrial membrane potential and membrane integrity mechanisms. There are studies using flow cytometry technique on Alternaria, Aspergillus, Fusarium and Penicillium mycotoxins including information about cell type, assay conditions and functional parameters. Most of the studies collected in the literature are on deoxynivalenol and zearalenone mycotoxins. Cell cycle analysis and apoptosis are the processes more widely investigated.

Involvement of enniatins-induced cytotoxicity in human HepG2 cells

Enniatins (ENNs) are mycotoxins found in Fusarium fungi and they appear in nature as mixtures of cyclic depsipeptides. The ability to form ionophores in the cell membrane is related to their cytotoxicity. Changes in ion distribution between inner and outer phases of the mitochondria affect to their metabolism, proton gradient, and chemiosmotic coupling, so a mitochondrial toxicity analysis of enniatins is highly recommended because they host the homeostasis required for cellular survival. Two ENNs, ENN A and ENN B on hepatocarcinoma cells (HepG2) at 1.5 and 3 μM and three exposure times (24, 48 and 72 h) were studied. Flow cytometry was used to examine their effects on cell proliferation, to characterize at which phase of the cell cycle progression the cells were blocked and to study the role of the mitochondrial in ENNs-induced apoptosis. In conclusion, apoptosis induction on HepG2 cells allowed to compare cytotoxic effects caused by both ENNs, A and B. It is reported the possible mechanism observed in MMP changes, cell cycle analysis and apoptosis/necrosis, identifying ENN B more toxic than ENN A.

Norcantharidin triggers cell death and DNA damage through S-phase arrest and ROS-modulated apoptotic pathways in TSGH 8301 human urinary bladder carcinoma cells

Norcantharidin (NCTD) is one of the ingredients of blister beetles which have been used in Chinese medicine for a long time. The purpose of this study was to investigate the inhibitory effects of NCTD on TSGH 8301 human bladder cancer cells in vitro and the mechanisms through which it exerts its anticancer action. Cell morphological analysis was performed using a phase-contrast microscope. The percentage of viable cells, cell cycle distribution, sub-G1 phase (apoptosis), reactive oxygen species (ROS) production and the levels of mitochondrial membrane potential (∆Ψ(m)) were analyzed by flow cytometry. DNA condensation and damage were determined by DAPI staining and comet assay. Apoptosis-associated protein level changes in TSGH 8301 cells following exposure to NCTD were examined, measured and determined by western blotting. Analysis of protein translocation was conducted by immunostaining and confocal laser microscopy. The results indicated that NCTD promoted cytotoxic effects, including the induction of cell morphological changes and the decrease in the percentage of viability, the induction of S-phase arrest as well as sub-G1 phase (apoptosis) in TSGH 8301 cells. The activities of caspase-3 and -9 were upregulated following NCTD treatment. Western blotting indicated that NCTD upregulated Fas, FasL, Bax, Bid, cytochrome c, caspase-3, -8 and -9 that led to the induction of apoptosis through the Fas extrinsic pathway. Furthermore, NCTD induced AIF and Endo G that were released from mitochondria to induce apoptosis through the mitochondrial-independent pathway. NCTD upregulated ROS production, downregulated ∆Ψ(m) and ERK, JNK, p38 protein kinases in TSGH 8301 cells. These findings suggest that NCTD triggers apoptosis in TSGH 8301 human bladder cancer cells via the Fas receptor, activation of the caspse-8, -9 and -3, mitochondrial-dependent and -independent pathways. NCTD may be useful for developing new therapeutic regimens for the treatment of bladder cancer.

Norcantharidin enhances ABT-737-induced apoptosis in hepatocellular carcinoma cells by transcriptional repression of Mcl-1

Small-molecule cell-permeable Bcl-2/Bcl-xL antagonist ABT-737 has recently emerged as a novel cancer therapeutic agent because it potently induces apoptosis in certain cancer cells. However, since ABT-737 binds to Mcl-1 with low affinity, ABT-737-mediated apoptosis signaling is inhibited in hepatocellular carcinoma (HCC) cells and other solid cancer cells due to the elevated expression of Mcl-1. Accordingly, strategies that target Mcl-1 are explored for overcoming ABT-737-resistance. In this study, we reported that Norcantharidin (NCTD), a small-molecule anticancer drug derived from Chinese traditional medicine blister beetle (Mylabris), induced transcriptional repression of Mcl-1 and considerably enhanced ABT-737-triggered cell viability inhibition and apoptosis in multiple HCC cell lines. Moreover, we observed that the enhancement of ABT-737-mediated apoptosis by NCTD was associated with activation of mitochondrial apoptosis signaling pathway, which involved cytosolic release of cytochrome c, cleavage of caspase-9 and caspase-3. Additionally, knockdown of Bax/Bak, the key effectors permeabilizing mitochondrial outer membrane significantly attenuated the enhancement, indicating mitochondrial apoptosis pathway played an essential role in the execution of the apoptosis. Finally, knockdown of Mcl-1 substantially potentiated ABT-737-mediated apoptotic cell death, confirming the potency of Mcl-1 repression by NCTD in enhancing ABT-737-induced apoptosis. These results therefore suggest that combination treatment with NCTD can overcome ABT-737 resistance and enhance ABT-737 therapeutic efficacy in treating human HCC.

Fighting fire with fire: poisonous Chinese herbal medicine for cancer therapy

ETHNOPHARMACOLOGICAL RELEVANCE

Following the known principle of "fighting fire with fire", poisonous Chinese herbal medicine (PCHM) has been historically used in cancer therapies by skilled Chinese practitioners for thousands of years. In fact, most of the marketed natural anti-cancer compounds (e.g., camptothecin derivatives, vinca alkaloids, etc.) are often known in traditional Chinese medicine (TCM) and recorded as poisonous herbs as well. Inspired by the encouraging precedents, significant researches into the potential of novel anticancer drugs from other PCHM-derived natural products have been ongoing for several years and PCHM is increasingly being recognized as a gathering place for promising anti-cancer drugs. The present review aimed at giving a rational understanding of the toxicity of PCHM and, especially, providing the most recent developments on PCHM-derived anti-cancer compounds.

MATERIALS AND METHODS

Information on the toxicity and safety control of PCHM, as well as PCHM-derived anti-cancer compounds, was gathered from the articles, books and monographs published in the past 20 years.

RESULTS

Based on an objective introduction to the CHM toxicity, we clarified the general misconceptions about the safety of CHM and summarized the traditional experiences in dealing with the toxicity. Several PCHM-derived compounds, namely gambogic acid, triptolide, arsenic trioxide, and cantharidin, were selected as representatives, and their traditional usage and mechanism of anti-cancer actions were discussed.

CONCLUSIONS

Natural products derived from PCHM are of extreme importance in devising new drugs and providing unique ideas for the war against cancer. To fully exploit the potential of PCHM in cancer therapy, more attentions are advocated to be focused on their safety evaluation and mechanism exploration.

Anticancer drugs from traditional toxic Chinese medicines

Many anticancer drugs are obtained from natural sources. Nature produces a variety of toxic compounds, which are often used as anticancer drugs. Up to now, there are at least 120 species of poisonous botanicals, animals and minerals, of which more than half have been found to possess significant anticancer properties. In spite of their clinical toxicity, they exhibit pharmacological effects and have been used as important traditional Chinese medicines for the different stages of cancer. The article reviews many structures such as alkaloids of Camptotheca acuminata, Catharanthus roseus and Cephalotaxus fortunei, lignans of Dysosma versipellis and Podophyllum emodi, ketones of Garcinia hanburyi, terpenoids of Mylabris and Ginkgo biloba, diterpenoids of Tripterygium wilfordii, Euphorbia fischeriana, Euphorbia lathyris, Euphorbia kansui, Daphne genkwa, Pseudolarix kaempferi and Brucea javanica, triterpenoids of Melia toosendan, steroids of Periploca sepium, Paris polyphylla and Venenum Bufonis, and arsenic compounds including Arsenicum and Realgar. By comparing their related phytochemistry, toxic effects and the recent advances in understanding the mechanisms of action, this review puts forward some ideals and examples about how to increase antitumour activity and/or reduce the side effects experienced with Chinese medicine.

Antimetastatic effects of norcantharidin on hepatocellular carcinoma by transcriptional inhibition of MMP-9 through modulation of NF-kB activity

BACKGROUND

The rate of morbidity and mortality of hepatocellular carcinoma (HCC) in Taiwan has not lessened because of difficulty in treating tumor metastasis. Norcantharidin (NCTD) is currently used as an anticancer drug for hepatoma, breast cancer, and colorectal adenocarcinoma. NCTD possesses various biological anticancer activities, including apoptosis. However, detailed effects and molecular mechanisms of NCTD on metastasis are unclear. Thus, HCC cells were subjected to treatment with NCTD and then analyzed to determine the effects of NCTD on cell metastasis.

METHODOLOGY/PRINCIPAL FINDINGS

Modified Boyden chamber assays revealed that NCTD treatment inhibited cell migration and invasion capacities of HCC cells substantially. Results of zymography and western blotting showed that activities and protein levels of matrix metalloproteinase-9 (MMP-9) and urokinase plasminogen activator (u-PA) were inhibited by NCTD. Western blot analysis showed that NCTD inhibits phosphorylation of ERK1/2. Testing of mRNA level, quantitative real-time PCR, and promoter assays evaluated the inhibitory effects of NCTD on MMP-9 and u-PA expression in HCC cells. The chromatin immunoprecipitation (ChIP) assay for analyzing the genomic DNA sequences bound to these proteins was reactive to the transcription protein nuclear factor (NF)-kappaB, which was inhibited by NCTD. The expression of NF-kappa B was measured by western blot analysis, which revealed decreased nuclear-factor DNA-binding activity after NCTD treatment.

CONCLUSIONS

NCTD inhibited MMP-9 and u-PA expression through the phosphorylation of ERK1/2 and NF-kappaB signaling pathway which serves as a powerful chemopreventive agent in HCC cell metastasis.