Norcantharidin-induced apoptosis in oral cancer cells is associated with an increase of proapoptotic to antiapoptotic protein ratio

The impact of Trifolium pratense extract on apoptosis and autophagy in NALM-6 cells: implications for B-ALL intervention

B-cell acute lymphoblastic leukemia (B-ALL), a prevalent malignancy predominantly affecting children, poses challenges such as drug resistance and cytotoxicity despite available treatment methods. The persistence of these challenges underscores the necessity for innovative therapeutic approaches to enhance efficacy. Natural compounds derived from plants, recognized for their potential to inhibit cancer cell growth, have drawn attention. Trifolium pratense extract, known for its significant anticancer properties in previous studies, was the focus of this investigation. This experimental study aimed to explore the impact of T. pratense extract on apoptosis and autophagy in NALM-6 cells. The cells were exposed to varying concentrations of the extract at specific time intervals, with viability and metabolic activity assessed using Trypan blue exclusion and MTT assays. Flow cytometry was employed to evaluate apoptosis using Annexin V/PI staining and ROS production using DCFH-DA staining. Real-time PCR was used to quantify gene expression related to apoptosis, autophagy, and oxidative stress, with data analysis performed using GraphPad PRISM software. Trifolium pratense extract demonstrated the capacity to induce apoptosis, autophagy, and significantly increase ROS production in NALM-6 cells. These effects were facilitated by the upregulation of corresponding genes. The MTT assay revealed an IC50 of 231 μg/mL at 48 h, and Flow cytometry analysis showed a 51.8% increase in apoptosis in this cell line. Overall, this study emphasizes the effectiveness of T. pratense extract in inducing autophagy and apoptosis pathways in NALM-6 cells derived from B-cell acute lymphoblastic leukemia, suggesting its potential as a candidate for further investigation as a supplement in ALL treatment.

Unlocking nature's arsenal: Nanotechnology for targeted delivery of venom toxins in cancer therapy

AIM

The aim of the present review is to shed light on the nanotechnological approaches adopted to overcome the shortcomings associated with the delivery of venom peptides which possess inherent anti-cancer properties.

BACKGROUND

Venom peptides although have been reported to demonstrate anti-cancer effects, they suffer from several disadvantages such as in vivo instability, off-target adverse effects, limited drug loading and low bioavailability. This review presents a comprehensive compilation of different classes of nanocarriers while underscoring their advantages, disadvantages and potential to carry such peptide molecules for in vivo delivery. It also discusses various nanotechnological aspects such as methods of fabrication, analytical tools to assess these nanoparticulate formulations, modulation of nanocarrier polymer properties to enhance loading capacity, stability and improve their suitability to carry toxic peptide drugs.

CONCLUSION

Nanotechnological approaches bear great potential in delivering venom peptide-based molecules as anticancer agents by enhancing their bioavailability, stability, efficacy as well as offering a spatiotemporal delivery approach. However, the challenges associated with toxicity and biocompatibility of nanocarriers must be duly addressed.

PERSPECTIVES

The everlasting quest for new breakthroughs for safer delivery of venom peptides in human subjects is fuelled by unmet clinical needs in the current landscape of chemotherapy. In addition, exhaustive efforts are required in obtaining and purifying the venom peptides followed by designing and optimizing scale up technologies.

Mapping the landscape of oral cancer research trends: a systematic scientometric review of global efforts

PURPOSE

The primary goal of this study was to assess the growth, most influential articles, countries, journals, authors, and papers published in the field of global oral cancer. Research articles on oral cancer, published between 1989 and 2022, were identified through the Web of Science database to achieve this.

METHODS

A comprehensive dataset comprising 7,178 documents was meticulously extracted from the Web of Science, forming the basis for scientometric analysis. A refined subset of 4,901 documents was judiciously selected following a rigorous screening process for meticulous, in-depth analysis.

RESULTS

The field has witnessed a remarkable publication surge, with the United States taking the lead in productivity. The journal Oral Oncology has become the foremost publication, renowned for its prolific output and widespread citation. This trend highlights the growing importance and interest in this domain, with researchers and experts worldwide contributing to the expanding body of knowledge. The United States' dominance in productivity suggests its strong commitment to advancing research in the field, while Oral Oncology's recognition underscores its influential role in disseminating cutting-edge findings and fostering scientific progress.

CONCLUSION

This scientometric analysis is a valuable resource for researchers, funding agencies, industry, and institutions, offering guidance and insights.

CLINICAL TRIAL NUMBER

Not Applicable.

Bibliometric Analysis and Systemic Review of Cantharidin Research Worldwide

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Tumor microenvironment remodeling in oral cancer: Application of plant derived-natural products and nanomaterials

Oral cancers consist of squamous cell carcinoma (SCC) and other malignancies in the mouth with varying degrees of invasion and differentiation. For many years, different modalities such as surgery, radiation therapy, and classical chemotherapy drugs have been used to control the growth of oral tumors. Nowadays, studies have confirmed the remarkable effects of the tumor microenvironment (TME) on the development, invasion, and therapeutic resistance of tumors like oral cancers. Therefore, several studies have been conducted to modulate the TME in various types of tumors in favor of cancer suppression. Natural products are intriguing agents for targeting cancers and TME. Flavonoids, non-flavonoid herbal-derived molecules, and other natural products have shown promising effects on cancers and TME. These agents, such as curcumin, resveratrol, melatonin, quercetin and naringinin have demonstrated potency in suppressing oral cancers. In this paper, we will review and discuss about the potential efficacy of natural adjuvants on oral cancer cells. Furthermore, we will review the possible therapeutic effects of these agents on the TME and oral cancer cells. Moreover, the potential of nanoparticles-loaded natural products for targeting oral cancers and TME will be reviewed. The potentials, gaps, and future perspectives for targeting TME by nanoparticles-loaded natural products will also be discussed.

Strategies for Targeting Serine/Threonine Protein Phosphatases with Small Molecules in Cancer

Among numerous posttranslational regulation patterns, phosphorylation is reversibly controlled by the balance of kinases and phosphatases. The major form of cellular signaling involves the reversible phosphorylation of proteins on tyrosine, serine, or threonine residues. However, altered phosphorylation levels are found in diverse diseases, including cancer, making kinases and phosphatases ideal drug targets. In contrast to the success of prosperous kinase inhibitors, design of small molecules targeting phosphatase is struggling due to past bias and difficulty. This is especially true for serine/threonine phosphatases, one of the largest phosphatase families. From this perspective, we aim to provide insights into serine/threonine phosphatases and the small molecules targeting these proteins for drug development, especially in cancer. Through highlighting the modulation strategies, we aim to provide basic principles for the design of small molecules and future perspectives for the application of drugs targeting serine/threonine phosphatases.

Norcantharidin induces G2/M arrest and apoptosis via activation of ERK and JNK, but not p38 signaling in human renal cell carcinoma ACHN cells

Renal cell carcinoma (RCC) is generally acknowledged as the most resistant primary malignancy unresponsive to conventional radiotherapy and chemotherapy treatments. Norcantharidin (NCTD), a therapeutic compound derived from medicinal plants, has been shown to trigger apoptosis, as well as antimetastatic and antioxidant activities in several tumor cells. However, NCTD's mechanism of antitumor activity in the RCC cell line remains unclear. In this study, we report that NCTD led to a time- and dose-dependent inhibition of cell proliferation. It had also markedly induced apoptosis and G2/M phase cell cycle arrest in a dose-dependent manner by decreasing the expressions of pro-caspase-3, pro-caspase-9, cyclin B1, and pCDC25C while increasing active caspase-3, cleaved-PARP, P21, and pCDC2 levels. Interestingly, NCTD treatment provoked the phosphorylation of extracellular-regulated protein kinase (ERK) and c-Jun-N-terminal kinase (JNK), but not of p38 MAPK. Moreover, SCH772984 and SP600125, ERK and JNK inhibitors, respectively, could partially abolish NCTD-induced apoptosis and G2/M phase cell cycle arrest. Collectively, these findings suggest that NCTD might activate JNK and ERK signaling pathways, consequently inducing apoptosis and G2/M arrest through the modulation of related proteins. This study provided evidence that NCTD is a promising therapeutic drug for the treatment of RCC.

Small-Molecule Drug Discovery in Triple Negative Breast Cancer: Current Situation and Future Directions

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, but an effective targeted therapy has not been well-established so far. Considering the lack of effective targets, where do we go next in the current TNBC drug development? A promising intervention for TNBC might lie in de novo small-molecule drugs that precisely target different molecular characteristics of TNBC. However, an ideal single-target drug discovery still faces a huge challenge. Alternatively, other new emerging strategies, such as dual-target drug, drug repurposing, and combination strategies, may provide new insight into the improvement of TNBC therapeutics. In this review, we focus on summarizing the current situation of a series of candidate small-molecule drugs in TNBC therapy, including single-target drugs, dual-target drugs, as well as drug repurposing and combination strategies that will together shed new light on the future directions targeting TNBC vulnerabilities with small-molecule drugs for future therapeutic purposes.

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.

Downregulation of c‑FLIP and upregulation of DR‑5 by cantharidin sensitizes TRAIL‑mediated apoptosis in prostate cancer cells via autophagy flux

Tumor necrosis factor (TNF)-related apop-tosis-inducing ligand (TRAIL), a type II transmembrane protein, is a part of the TNF superfamily of cytokines. Cantharidin, a type of terpenoid, is extracted from the blister beetles (Mylabris genus) used in Traditional Chinese Medicine. Cantharidin elicits antibiotic, antiviral and antitumor effects, and can affect the immune response. The present study demonstrated that a cantharidin and TRAIL combination treatment regimen elicited a synergistic outcome in TRAIL-resistant DU145 cells. Notably, it was also identified that cantharidin treatment initiated the downregulation of cellular FLICE-like inhibitory protein (c-FLIP) and upregulation of death receptor 5 (DR-5), and sensitized cells to TRAIL-mediated apoptosis by initiating autophagy flux. In addition, cantharidin treatment increased lipid-modified microtubule-associated proteins 1A/1B light chain 3B expression and significantly attenuated sequestosome 1 expression. Attenuation of autophagy flux by a specific inhibitor such as chloroquine and genetic modification using ATG5 small interfering RNA abrogated the cantharidin-mediated TRAIL-induced apoptosis. Overall, the results of the present study revealed that cantharidin effectively sensitized cells to TRAIL-mediated apoptosis and its effects are likely to be mediated by autophagy, the downregulation of c-FLIP and the upregulation of DR-5. They also suggested that the combination of cantharidin and TRAIL may be a successful therapeutic strategy for TRAIL-resistant prostate cancer.

Regulation of collagen type XVII expression by miR203a-3p in oral squamous cell carcinoma cells

Collagen type XVII (COL17) is expressed in various tissues and its aberrant expression is associated with tumour progression. In this study, we investigated the regulation of COL17 expression in oral squamous cell carcinoma (OSCC) using the cell lines NA, SAS, Ca9-22, and Sa3. COL17 was induced upon p53 activation by cisplatin in SAS; however, this effect was more limited in NA and hardly in Ca9-22 and Sa3, with mutated p53. Moreover, COL17 was found to be regulated by miR203a-3p in all cell lines. Our data suggest that COL17 expression in OSCC cell lines is regulated by p53 and miR203a-3p.

Antitumor evaluation of carboxymethyl chitosan based norcantharidin conjugates against gastric cancer as novel polymer therapeutics

Novel polymer-drug conjugates (CNC) were prepared from carboxymethyl chitosan (CMCS) and norcantharidin (NCTD) via amidation reaction and characterized by FTIR and ¹H NMR spectroscopy. The aim of this study was to elucidate the antitumor efficacy of CNC on gastric cancer and the possible underlying mechanisms. The CNC conjugates possessed significant inhibitory effects on the proliferation of SGC-7901 cells and suppressed the migration as well as tube formation of HUVECs. Besides, Hoechst 33258 staining and Annexin V-FITC/PI detection suggested that the conjugates were more effective in triggering apoptosis of SGC-7901 cells compared with free NCTD. Moreover, CNC remarkably reduced systemic toxicity and enhanced the antitumor efficacy in vivo with a tumor suppression rate of 59.57% against SGC-7901 gastric tumor in BALB/c nude mice. Further investigation about the underlying mechanisms indicated that CNC could upregulate expressions of TNF-α and Bax, and downregulate expressions of VEGF, Bcl-2, MMP-2 and MMP-9, thereby inhibiting tumor metastasis and inducing apoptosis in vivo. Overall, our results demonstrated that CNC might be a promising and feasible polymer therapeutics for gastrointestinal tumor therapy.

Targeting the unfolded protein response in head and neck and oral cavity cancers

Many FDA-approved anti-cancer therapies, targeted toward a wide array of molecular targets and signaling networks, have been demonstrated to activate the unfolded protein response (UPR). Despite a critical role for UPR signaling in the apoptotic execution of cancer cells by many of these compounds, the authors are currently unaware of any instance whereby a cancer drug was developed with the UPR as the intended target. With the essential role of the UPR as a driving force in the genesis and maintenance of the malignant phenotype, a great number of pre-clinical studies have surged into the medical literature describing the ability of dozens of compounds to induce UPR signaling in a myriad of cancer models. The focus of the current work is to review the literature and explore the role of the UPR as a mediator of chemotherapy-induced cell death in squamous cell carcinomas of the head and neck (HNSCC) and oral cavity (OCSCC), with an emphasis on preclinical studies.

Dual inhibition of Akt and ERK signaling induces cell senescence in triple-negative breast cancer

Activated Akt and ERK signaling pathways are closely related to breast cancer progression, and Akt or ERK inhibition induces cell senescence. However, the crosstalk between the Akt and ERK signaling pathways in cell senescence and how to simultaneously suppress Akt and ERK signaling in triple-negative breast cancer (TNBC) are undefined. In this study, we found that norcantharidin (NCTD) effectively induced cell senescence and cell cycle arrest in TNBC in vitro, which was accompanied by a decline in phosphorylated Akt and ERK1/2 and a rise in p21 and p16. The inhibitors LY294002 and U0126 imitated the effect of NCTD when these two inhibitors were combined regardless of crosstalk between these two signaling pathways. In addition, NCTD inhibited the growth of xenografts via downregulation of phosphorylated Akt and ERK1/2 and upregulation of p21 in vivo. However, NCTD upregulated the level of soluble signaling factors of the senescence-associated secretory phenotype (SASP) in a NF-κB-independent manner. Collectively, these findings demonstrate that NCTD induced cell senescence and cell cycle arrest mainly by simultaneously blocking Akt and ERK signaling in TNBC, suggesting that NCTD may be used as a potential adjuvant therapy in TNBC.

Venom as therapeutic weapon to combat dreadful diseases of 21st century: A systematic review on cancer, TB, and HIV/AIDS

Cancer and infectious diseases are the preeminent causes of human morbidities and mortalities worldwide. At present, chemotherapy, radiotherapy, immunotherapy, and gene therapy are considered as predominant options in order to treat cancer. But these therapies provide inadequate consequences by affecting both the normal and tumor cells. On the other hand, tuberculosis (TB), and HIV (human immunodeficiency virus) infections are significant threats, causing over a million mortalities each year. The extensive applications of antibiotics have caused the microbes to acquire resistance to the existing antibiotics. With the emerging dilemma of drug resistant microbes, it has become imperative to identify novel therapeutic agents from natural sources as emphatic alternative approach. Over the past few decades, venoms derived from several reptiles, amphibians, and arthropods including snakes, scorpions, frogs, spiders, honey bees, wasps, beetles, caterpillars, ants, centipedes, and sponges have been identified as efficient therapeutics. Venoms constitute plethora of bioactive components, particularly peptides, enzymes, and other chemical entities, which exhibit a large array of anticancer and anti-pathogenic activities. This review highlights the panorama of bioactive components of animal venoms divulging the anticancer, anti-tubercular, and anti-HIV activities. In a nutshell, this context discloses the decisive role of animal venoms as alternative natural resources to combat these deadly diseases of 21^st century, and propounding the plausible development of new therapeutic drugs in the present era.

Norcantharidin enhances antitumor immunity of GM-CSF prostate cancer cells vaccine by inducing apoptosis of regulatory T cells

Norcantharidin (NCTD) is a promising antitumor drug with low toxicity. It was reported to be able to regulate immunity, but the mechanism is not yet clear. Here we explored whether NCTD could enhance the antitumor immunity induced by prostate cancer cell vaccine. The results of the in vitro study showed that NCTD induced apoptosis and inhibited proliferation of regulatory T cells (Tregs). Mechanistic research showed that NCTD inhibited Akt activation and activated FOXO1 transcription, resulting in a pro‐apoptotic effect. The results of the in vivo study showed that more tumor‐infiltrating Tregs existed within peripheral blood and tumor tissue after treatment with the vaccine. Adding NCTD to vaccine treatment could decrease the number of tumor‐infiltrating Tregs and increase the number of CD4⁺ and CD8⁺ T cells. Combination therapy with NCTD and vaccine was more effective in inhibiting tumor growth than the vaccine alone. In general, this is the first report that NCTD could induce apoptosis of Tregs and enhance the vaccine‐induced immunity.

NCTD promotes Birinapant-mediated anticancer activity in breast cancer cells by downregulation of c-FLIP

Second mitochondria-derived activator of caspases (SMAC) mimetics is a class of new anticancer agents. However, most cancers exhibit de novo or acquired resistance to SMAC mimetics, posting a problem for broad applications in clinic, and highlighting the necessity of exploring combinational strategies to circumvent SMAC mimetic-resistance. We here showed that Norcantharidin, a drug that is currently being used in cancer treatment, significantly enhanced SMAC mimetic Birinapant-mediated cell viability inhibition and robustly promoted apoptosis in established breast carcinoma cell lines, as well as in primary breast carcinoma cells. Mechanistically, we revealed that Norcantharidin effectively reduced the levels of two major protein isoforms of cellular FLICE-like inhibitor protein(c-FLIP), namely c-FLIP long (c-FLIPL) and c-FLIP short (c-FLIPS). Moreover, Norcantharidin markedly enhanced Birinapant-triggered caspase-8/caspase-3 cascade. Inhibition of caspase-8 activity by a synthetic peptide Z-IETD-FMK significantly attenuated cell death induction by the combination, suggesting that caspase-8 plays a critical role in the anticancer action. In conclusion, our study suggests that the combination of SMAC mimetics with Norcantharidin represents a novel strategy in breast cancer therapy and warrants further studies.

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.

Induction of oxidative stress and cell apoptosis by selenium: the cure against oral carcinoma

Oral carcinoma (OC) remains one of the most difficult malignancies to cure. selenium (Se) is an essential trace mineral for human and animals, but high concentrations of Se induce apoptosis and oxidative effects. Although cell apoptosis has been evidenced as a critical mechanism mediating the anticancer activity of Se, the underlying molecular mechanisms remain elusive. To explore the role of Se in rat OC, we examined the weather the oxidative stress-mediated apoptotic pathway induced by Se was involved in the development of OC. In this study, we successfully constructed the OC rat model by 4-Nitroquinoline-1-oxide (4-NQO) exposure which reflected from histopathological observations. Se-induced the productions of methane dicarboxylic aldehyde (MDA) and reactive oxygen species (ROS), which was accompanied by the inhibition of superoxide dismutase (SOD) both in vivo and vitro. The anti-apoptotic gene (Bcl-2) was down-regulated and pro-apoptosis members (Bax, Bak, Cyt-c, caspase9 and caspase3) were up-regulated by Se in OC cells. Meanwhile, we also found that Se could strongly inhibited the cell proliferation of OC lines in vitro. These results suggested that excessive Se could effectively cause oxidative stress and induce apoptosis in OC cells, as a result the OC was also inhibited to some extent. Therefore, the information presented in this study is believed to be helpful in supplementing data for further therapy of OC.

Norcantharidin combined with Coix seed oil synergistically induces apoptosis and inhibits hepatocellular carcinoma growth by downregulating regulatory T cells accumulation

The immune system plays a critical role in exerts effects in the growth and progression of hepatocellular carcinoma (HCC), which needs interacting approaches for effective therapy. In this study, we have found that the Norcantharidin (NCTD) + Coix lacryma-jobi seed oil (CLSO) combination exhibited more potent antitumor effects in an terms of cytotoxicity and apoptotic induction in human HepG2 and HepG2/ADM cells than NCTD or CLSO alone. In vivo, administration of NCTD+CLSO combinations significantly suppressed the formation of tumor in Hepal-1 hepatoma-bearing mice. Furthermore, we found that the in vitro co-cultures of HepG2 or HepG2/ADM cells with PBMCs from healthy donors led to an increase in the number of CD4 + CD25 + T cells. This increase was down-regulated by the combination effectively. Down-regulation of FoxP3 mRNA and protein expression occurred during the combination in the co-cultures. The amount of Tregs of Hepal-1 hepatoma-bearing mice was significantly decreased in the combination treated group. The combination down-regulated the expression of FoxP3, CTLA-4 and Tregs related cytokine (TGF-β and IL-10) in the serum of tumor bearing mice. Taken together, these results suggest that the most valuable aspect of the NCTD+CLSO combined use improves the anti-tumor activity and regulates tumor infiltrating Tregs.

Norcantharidin induces mitochondrial-dependent apoptosis through Mcl-1 inhibition in human prostate cancer cells

Norcantharidin (NCTD) is the demethylated form of cantharidin that exhibits anticancer potential in many cancer cell types. Recent reports suggest that NCTD targeting ROS/AMPK and DNA replication signaling pathway could be an effective strategy for the treatment of PCa cells. However, supportive evidence is limited to the effect of NCTD that induction of apoptosis through suppression of the Mcl-1. Here, we show that NCTD induced PCa cell apoptosis and triggered caspase activation, which was associated with mitochondria dysfunction. Mechanistic investigations suggested that NCTD modulated the Akt signaling via increased nuclear translocation and interaction with the myeloid cell leukemia-1 (Mcl-1) promoter by FOXO4, resulting in an apoptotic effect. Moreover, miR-320d, which targets Mcl-1, was significantly upregulated after NCTD treatment. Overexpression of miR-320d by NCTD induced mitochondria dysfunction and apoptosis, which was notably attenuated with a miR-320d inhibitor. In vivo xenograft analysis revealed that NCTD significantly reduced tumor growth in mice with PC3 tumor xenografts. Taken together, our results provide new insights into the critical role of NCTD in suppressing Mcl-1 via epigenetic upregulation of miR-320d, resulting in PCa cell apoptosis.

Norcantharidin inhibits IL-6-induced epithelial‑mesenchymal transition via the JAK2/STAT3/TWIST signaling pathway in hepatocellular carcinoma cells

Epithelial-mesenchymal transition (EMT), plays a vital role in hepatocellular carcinoma (HCC) development and metastasis. Norcantharidin (NCTD; 7-oxabicyclo (2.2.1) heptane-2,3-dicarboxylic anhydride) plays anticancer roles in the regulation of tumor cell proliferation, apoptosis and migration. However, the molecular mechanism of HCC EMT and the effects of NCTD in the HCC EMT process have been either poorly elucidated or not studied. In this study, HCC EMT was induced by the treatment of IL-6 and various concentrations of NCTD (0, 30, 60 and 120 µM) were treated with HCC cell lines, HCCLM3 and SMMC-7721. We investigated the effect of NCTD on the invasion of HCC cells by using Transwell assay. Immunofluorescence staining, western blot analysis and quantitative RT-PCR were performed to evaluate the protein and mRNA expression levels of HCC cells. Here, using cell line models, our data demonstrated that interleukin 6 (IL-6) induced EMT through the JAK/STAT3/TWIST pathway in HCC. Moreover, our studies revealed that NCTD markedly inhibited IL-6-induced EMT and cell invasiveness. Signaling studies revealed that NCTD sufficiently suppressed JAK/STAT3/TWIST signaling to reverse the IL-6-promoting effects. Collectively, these data provide evidence for the use of NCTD as a potential anticancer drug in HCC metastatic patients.

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.

FAM46C is critical for the anti-proliferation and pro-apoptotic effects of norcantharidin in hepatocellular carcinoma cells

Norcantharidin (NCTD), a demethylated analog of cantharidin derived from Chinese traditional medicine blister beetle, has been currently used as an anticancer drug for various cancers including hepatocellular carcinoma (HCC). In this study, for a more comprehensive understanding of the targets of NCTD in HCC, next-generation RNA-Seq was utilized. We revealed that the expression of FAM46C, which has been reported as a tumor suppressor for multiple myeloma, was enhanced after NCTD treatment. Re-analysis of TCGA (The Cancer Genome Atlas) LIHC (liver hepatocellular carcinoma) dataset demonstrated that FAM46C expression was significantly lower in HCC tissues than in normal liver tissues. NCTD injection or FAM46C overexpression could mitigate diethylnitrosamine (DEN)-initiated HCC in mice. Ectopic expression of FAM46C in two HCC cell lines, SMCC-7721 and SK-Hep-1, significantly repressed cell proliferation, and increased cells population in G2/M phase and cell apoptotic rate. We also found that FAM46C overexpression caused a notable decrease in Ras expression, MEK1/2 phosphorylation and ERK1/2 phosphorylation. More importantly, FAM46C knockdown significantly weakened the biological effects of NCTD on HCC cells, which suggested NCTD exerted the anticancer functions partially through up-regulating FAM46C. In conclusion, FAM46C, a tumor suppressor for HCC, is important for the anti-proliferation and proapoptotic effects of NCTD.

Cantharidin Induced Oral Squamous Cell Carcinoma Cell Apoptosis via the JNK-Regulated Mitochondria and Endoplasmic Reticulum Stress-Related Signaling Pathways

Oral cancer is a subtype of head and neck cancer which represents 2.65% of all human malignancies. Most of oral cancer is histopathologically diagnosed as oral squamous cell carcinoma (OSCC). OSCC is characterized by a high degree of local invasion and a high rate of metastasis to the cervical lymph nodes. How to prevention and treatment of OSCC is important and imperative. Here, we investigated the therapeutic effect and molecular mechanism of cantharidin, an active compound isolated from blister beetles, on OSCC in vitro. Results showed that cantharidin significantly decreased cell viability in human tongue squamous carcinoma-derived SAS, CAL-27, and SCC-4 cell lines. The further mechanistic studies were carried out in SAS cells. Cantharidin also significantly increased apoptosis-related signals, including caspase-9, caspase-7 and caspase-3 proteins. Besides, cantharidin decreased mitochondrial transmembrane potential (MMP) and induced cytochrome c and apoptosis inducing factor (AIF) release. Cantharidin also increased Bax, Bid, and Bak protein expressions and decreased Bcl-2 protein expression. Cantharidin could also increase the endoplasmic reticulum (ER) stress signals, including the expressions of phosphorylated eIF-2α and CHOP, but not Grp78 and Grp94. Furthermore, cantharidin reduced pro-caspase-12 protein expression. In signals of mitogen-activated protein kinases, cantharidin increased the phosphorylation of JNK, but not ERK and p38. Transfection of shRNA-JNK to OSCC cells effectively reversed the cantharidin-induced cell apoptotic signals, including the mitochondrial and ER stress-related signaling molecules. Taken together, these findings suggest that cantharidin induces apoptosis in OSCC cells via the JNK-regulated mitochondria and ER stress-related signaling pathways.

Norcantharidin induces apoptosis in human prostate cancer cells through both intrinsic and extrinsic pathways

BACKGROUND

Norcantharidin, a modified pure compound from blister beetles, was previously demonstrated to induce apoptosis of cancer cells. This study investigated its anti-cancer activity in prostate cancer cells and the mechanisms involved.

METHODS

Two human prostate cancer cell lines, 22Rv1 and Du145, were treated with norcantharidin at concentrations ranging from 3 to 30μg/ml. Cytotoxic effect of norcantharidin was determined by use of the 3-(4,5-dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) assay. The effects of apoptosis were evaluated by cell death assay, Caspase-3, -8, -9 activity and cytochrome c release. The apoptotic related protein expressions (Bcl-2 family and inhibitor of apoptosis proteins) were determined using western blotting.

RESULTS

An MTT assay revealed that norcantharidin induced cytotoxicity against both prostate cancer cells in dose- and time-dependent manners. Treatment with norcantharidin at 3μg/ml or higher significantly increased oligonucleosomal formation with concomitant appearance of PARP cleavage, implicating the induction of apoptosis. Norcantharidin intrinsically elevated cytosolic cytochrome c levels and activated caspase-3, -8, and -9. Extrinsically, it upregulated the expression of not only the death receptors Fas and DR5 in 22Rv1 cells, but also of RIP and TRADD adaptor proteins in Du145 cells. Mechanistically, norcantharidin increased ratios of pro-/anti-apoptotic proteins and decreased expression of IAP family member proteins, including cIAP1 and survivin, regardless of the distinct status of androgen receptor expression in both cells.

CONCLUSIONS

Norcantharidin exhibited cytotoxicity against 22Rv1 and Du145 prostate cancer cells by inducing both intrinsic and extrinsic apoptotic pathways and could thus potentially be a remedy for prostate cancer.

Folate receptor-targeted liposomes loaded with a diacid metabolite of norcantharidin enhance antitumor potency for H22 hepatocellular carcinoma both in vitro and in vivo

The diacid metabolite of norcantharidin (DM-NCTD) is clinically effective against hepatocellular carcinoma (HCC), but is limited by its short half-life and high incidence of adverse effects at high doses. We developed a DM-NCTD-loaded, folic acid (FA)-modified, polyethylene glycolated (DM-NCTD/FA-PEG) liposome system to enhance the targeting effect and antitumor potency for HCC at a moderate dose based on our previous study. The DM-NCTD/FA-PEG liposome system produced liposomes with regular spherical morphology, with mean particle size approximately 200 nm, and an encapsulation efficiency >80%. MTT cytotoxicity assays demonstrated that the DM-NCTD/FA-PEG liposomes showed significantly stronger cytotoxicity effects on the H22 hepatoma cell line than did PEG liposomes without the FA modification (P<0.01). We used liquid chromatography–mass spectrometry for determination of DM-NCTD in tissues and tumors, and found it to be sensitive, rapid, and reliable. In addition, the biodistribution study showed that DM-NCTD liposomes improved tumor-targeting efficiency, and DM-NCTD/FA-PEG liposomes exhibited the highest efficiency of the treatments (P<0.01). Meanwhile, the results indicated that although the active liposome group had an apparently increased tumor-targeting efficiency of DM-NCTD, the risk to the kidney was higher than in the normal liposome group. With regard to in vivo antitumor activity, DM-NCTD/FA-PEG liposomes inhibited tumors in H22 tumor-bearing mice better than either free DM-NCTD or DM-NCTD/PEG liposomes (P<0.01), and induced considerably more significant cellular apoptosis in the tumors, with no obvious toxicity to the tissues of model mice or the liver tissue of normal mice, as shown by histopathological examination. All these results demonstrate that DM-NCTD-loaded FA-modified liposomes might have potential application for HCC-targeting therapy.

High-Throughput Phenotypic Screening of Human Astrocytes to Identify Compounds That Protect Against Oxidative Stress

Astrocytes are the predominant cell type in the nervous system and play a significant role in maintaining neuronal health and homeostasis. Recently, astrocyte dysfunction has been implicated in the pathogenesis of many neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Astrocytes are thus an attractive new target for drug discovery for neurological disorders. Using astrocytes differentiated from human embryonic stem cells, we have developed an assay to identify compounds that protect against oxidative stress, a condition associated with many neurodegenerative diseases. This phenotypic oxidative stress assay has been optimized for high-throughput screening in a 1,536-well plate format. From a screen of approximately 4,100 bioactive tool compounds and approved drugs, we identified a set of 22 that acutely protect human astrocytes from the consequences of hydrogen peroxide-induced oxidative stress. Nine of these compounds were also found to be protective of induced pluripotent stem cell-differentiated astrocytes in a related assay. These compounds are thought to confer protection through hormesis, activating stress-response pathways and preconditioning astrocytes to handle subsequent exposure to hydrogen peroxide. In fact, four of these compounds were found to activate the antioxidant response element/nuclear factor-E2-related factor 2 pathway, a protective pathway induced by toxic insults. Our results demonstrate the relevancy and utility of using astrocytes differentiated from human stem cells as a disease model for drug discovery and development.

SIGNIFICANCE

Astrocytes play a key role in neurological diseases. Drug discovery efforts that target astrocytes can identify novel therapeutics. Human astrocytes are difficult to obtain and thus are challenging to use for high-throughput screening, which requires large numbers of cells. Using human embryonic stem cell-derived astrocytes and an optimized astrocyte differentiation protocol, it was possible to screen approximately 4,100 compounds in titration to identify 22 that are cytoprotective of astrocytes. This study is the largest-scale high-throughput screen conducted using human astrocytes, with a total of 17,536 data points collected in the primary screen. The results demonstrate the relevancy and utility of using astrocytes differentiated from human stem cells as a disease model for drug discovery and development.

Cantharidin inhibits cell proliferation and induces apoptosis through G2/M phase cell cycle arrest in hepatocellular carcinoma stem cells

The present study was designed to investigate the effect of cantharidin on cell proliferation, ability of selfrenewal, cell cycle arrest and induction of apoptosis in HepG2 hepatocellular carcinoma stem cells (HCSCs). It was observed that cantharidin treatment exhibited dose- and time-dependent inhibitory effect on the viability of HCSCs. The inhibition of cell viability by cantharidin in HepG2 CD133+ and parental cells was significant at the concentration 5 and 15 µM, respectively after 48 h. Cantharidin treatment inhibited the self-renewal ability of the HCSCs and the expression of β-catenin and cyclin D1. Flow cytometry revealed that cantharidin treatment at 5 µM concentration significantly increased the cell population in G2/M phase and decreased the population in the G1 phase. Cantharidin treatment in the HCSCs for 48 h increased expression of histone H2AX, Myt1, cyclin A2, cyclin B1, p53 and cdc2 (Tyr15) phosphorylation significantly compared to the parental cells. Exposure of the HCSCs to cantharidin for 48 h at a concentration of 5 µM caused a significant increase in the proportion of apoptotic cells. Therefore, cantharidin is a promising agent for the hepatocellular carcinoma treatment.

Synergistic Effect and Molecular Mechanisms of Traditional Chinese Medicine on Regulating Tumor Microenvironment and Cancer Cells

The interaction of tumor cells with the microenvironment is like a relationship between the “seeds” and “soil,” which is a hotspot in recent cancer research. Targeting at tumor microenvironment as well as tumor cells has become a new strategy for cancer treatment. Conventional cancer treatments mostly focused on single targets or single mechanism (the seeds or part of the soil); few researches intervened in the whole tumor microenvironment and achieved ideal therapeutic effect as expected. Traditional Chinese medicine displays a broad range of biological effects, and increasing evidence has shown that it may relate with synergistic effect on regulating tumor microenvironment and cancer cells. Based on literature review and our previous studies, we summarize the synergistic effect and the molecular mechanisms of traditional Chinese medicine on regulating tumor microenvironment and cancer cells.

The proapoptotic protein Bim is up regulated by 1α,25-dihydroxyvitamin D3 and its receptor agonist in endothelial cells and transformed by viral GPCR associated to Kaposi sarcoma

We have previously shown that 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] and its less calcemic analog TX 527 induce apoptosis via caspase-3 activation in endothelial cells (SVEC) and endothelial cells transformed by the viral G protein-coupled receptor associated to Kaposi sarcoma (vGPCR). In this work, we studied whether intrinsic apoptotic pathway could be activated by changing the balance between anti and pro-apoptotic proteins. Time response qRT-PCR analysis demonstrated that the mRNA level of anti-apoptotic gene Bcl-2 decreased after 12h and increased after 48h treatment with 1α,25(OH)2D3 or TX 527 in SVEC and vGPCR cells, whereas its protein level remained unchanged through time. mRNA levels of pro-apoptotic gene Bax significantly increased only in SVEC after 24 and 48h treatment with 1α,25(OH)2D3 and TX 527 although its protein levels remained unchanged in both cell lines. Bim mRNA and protein levels increased in SVEC and vGPCR cells. Bim protein increase by 1α,25(OH)2D3 and TX 527 was abolished when the expression of vitamin D receptor (VDR) was suppressed. On the other hand, Bortezomib (0.25-1nM), an inhibitor of NF-κB pathway highly activated in vGPCR cells, increased Bim protein levels and induced caspase-3 cleavage. Altogether, these results indicate that 1α,25(OH)2D3 and TX 527 trigger apoptosis by Bim protein increase which turns into the activation of caspase-3 in SVEC and vGPCR cells. Moreover, this effect is mediated by VDR and involves NF-κB pathway inhibition in vGPCR.

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.

Insights into the key interactions between human protein phosphatase 5 and cantharidin using molecular dynamics and site-directed mutagenesis bioassays

Serine/threonine protein phosphatase 5 (PP5) is a promising novel target for anticancer therapies. This work aims to uncover the key interactions at the atomic level between PP5 and three inhibitors (cantharidin, norcantharidin and endothall). We found that, unlike previous report, Arg 100 contributes less to PP5-inhibitor binding, and the residues His 69, Asn 128, His 129, Arg 225, His 252 and Arg 250 are of importance to PP5-inhibitor binding. The hydrophobic interactions established between the residues Val 254, Phe 271 and Tyr 276, especially Glu 253, are very important to enhance the inhibitive interaction. We suggested that, to increase the inhibitory activity, the interactions of inhibitor with three negatively charged unfavorable interaction residues, Asp 99, Glu 130 and Asp 213, should be avoided. However, the interactions of inhibitor with favorable interaction residue Arg 250 could enhance the inhibitory activity. The Manganese ion 2 (MN2) unfavorably contribute to the total interaction free energies. The coordination between MN2 and chemical group of inhibitor should be eliminated. This work provides insight into how cantharidin and its analogs bind to PP5c at the atomic level and will facilitate modification of cantharidin-like chemicals to rationally develop more specific and less cytotoxic anti-cancer drugs.

A potential small-molecule synthetic antilymphangiogenic agent norcantharidin inhibits tumor growth and lymphangiogenesis of human colonic adenocarcinomas through blocking VEGF-A,-C,-D/VEGFR-2,-3 "multi-points priming" mechanisms in vitro and in vivo

Background

Tumor lymphangiogenesis plays an important role in promoting growth and metastasis of tumors, but no antilymphangiogenic agent is used clinically. Based on the effect of norcantharidin (NCTD) on lymphangiogenesis of human lymphatic endothelial cells (LECs), we firstly investigated the antilymphangiogenic activity of NCTD as a tumor lymphangiogenic inhibitor for human colonic adenocarcinomas (HCACs).

Methods

In vivo and in vitro experiments to determine the effects of NCTD on tumor growth and lymphangiogenesis of the in-situ colonic xenografts in nude mice, and lymphatic tube formation of the three-dimensional (3-D) of the co-culture system of HCAC HT-29 cells and LECs were done. Proliferation, apoptosis, migration, invasion, Ki-67, Bcl-2 and cell cycle of LECs and the co-culture system in vitro were respectively determined. Streparidin-peroxidase staining, SABC, western blotting and RT-PCR were respectively used to examine the expression of LYVE-1, D2-40, CK20 (including their LMVD), and VEGF-A, VEGF-C, VEGF-D, VEGFR-2 and VEGFR-3 in vitro and in vivo.

Results

NCTD inhibited tumor growth and lymphangiogenesis of the in-situ colonic xenografts in vivo, and these observations were confirmed by facts that lymphatic tube formation, proliferation, apoptosis, migration, invasion, S-phase cell cycle, and Ki-67 and Bcl-2 expression in vitro, and LYVE-1, D2-40, CK20 expression and their LMVD in vitro and in vivo were inhibited and affected. Furthermore, the expression of VEGF-A, VEGF-C, VEGF-D, VEGFR-2 and VEGFR-3 at protein/mRNA levels in the process of lymphatic tube formation in vitro and tumor lymphangiogenesis in vivo was downregulated; NCTD in combination with mF4-31C1 or Sorafenib enhanced these effects.

Conclusions

NCTD inhibits tumor growth and lymphangiogenesis of HCACs through “multi-points priming” mechanisms i.e. affecting related malignant phenotypes, inhibiting Ki-67 and Bcl-2 expression, inducing S-phase cell cycle arrest, and directly or indirectly downregulating VEGF-A,-C,-D/VEGFR-2,-3 signaling pathways. The present finding strongly suggests that NCTD could serve as a potential antilymphangiogenic agent for tumor lymphangiogenesis and is of importance to explore NCTD is used for antitumor metastatic comprehensive therapy for HCACs.

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.

Norcantharidin enhances ABT-263-mediated anticancer activity in neuroblastoma cells by upregulation of Noxa

Neuroblastoma is an aggressive childhood disease. Even with intensive conventional treatments, the long term survival rate for children with neuroblastoma remains less than 40%, highlighting the importance of finding new therapies. Bcl-2 family proteins play crucial roles in survival, proliferation and chemotherapeutic resistance of neuroblastoma cells. Therefore, targeting Bcl-2 with small molecule inhibitor ABT-263 could be a novel strategy for treatment of neuroblastoma. However, previous studies indicated that most neuroblastoma cell lines are resistant to ABT-263-mediated apoptosis. Thus, it is crucial to discover approaches that could overcome ABT-263 resistance. In this study, we examined the anticancer activity of ABT-263 in combination with norcantharidin (NCTD), a small-molecule anticancer drug derived from a traditional Chinese medicine, in human malignant neuroblastoma cells. We found that NCTD substantially enhanced ABT-263-mediated apoptosis induction, cell viability inhibition, and clonal formation inhibition in neuroblastoma SH-SY5Y and CHLA-119 cell lines. Moreover, the combination anticancer activity was accompanied by upregulation of Noxa, and was associated with characteristics of mitochondrial apoptosis signaling, such as cytosolic release of cytochrome c, activation of caspase-9,-3, and cleavage of PARP. Notably, we observed that knockdown of Noxa significantly attenuated cell death induction by cotreatment with ABT-263 and NCTD, indicating Noxa essentially contributes to the combination anticancer effect. Collectively, our study demonstrated that NCTD could overcome ABT-263-resistance in neuroblastoma cells, and suggested that combinational treatment of ABT-263 with NCTD might be a novel therapeutic option for children with neuroblastoma.

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.

Determination and pharmacokinetic study of the diacid metabolite of norcantharidin in beagle plasma by use of liquid chromatography-tandem mass spectrometry

Because norcantharidin (NCTD) is unstable and subject to ring opening and hydrolysis, the diacid metabolite of norcantharidin (DM-NCTD) is the stable form of NCTD found in normal saline solution. Conversion of NCTD to DM-NCTD is almost 100%, making it possible to determine and investigate the pharmacokinetics of DM-NCTD converted from NCTD. In this paper, a sensitive, simple and selective liquid chromatographic-tandem mass spectrometric method was developed and validated for determination of DM-NCTD in beagle plasma. DM-NCTD was detected in multiple-reaction monitoring (MRM) mode by using the dehydrated ion 169.3 as precursor ion and its product ion 123.1 as the detected ion. Ribavirin was used as internal standard and detected in MRM mode by use of precursor ions, resulting in a product ion transition of m/z 267.1 → 135.1. This method was successfully used for a pharmacokinetic study of DM-NCTD in beagles after intravenous administration of DM-NCTD in normal saline solution at doses of 0.39, 0.78, and 1.6 mg kg(-1). DM-NCTD had dose-dependent kinetics across the dosage range investigated, with enhanced T(1/2α) and AUC(0-12) and apparently decreasing V(d) and CL with increasing dosage. After single-dose administration, T(1/2α) ranged from 0.20 to 0.55 h, AUC(0-12) from 1.81 to 43.6 μg mL(-1) h(-1), V(d) from 228 to 55.9 mL kg(-1), and CL from 220 to 36.5 mL kg(-1) h(-1) (P < 0.01). The results indicated nonlinear pharmacokinetic behavior of DM-NCTD in beagles, suggesting that the risk of DM-NCTD in normal saline solution intoxication may be non-proportionally increased at higher doses.

Roles of autophagy-related genes Beclin-1 and LC3 in the development and progression of prostate cancer and benign prostatic hyperplasia

Prostate cancer (PCa) is common in Western populations and the second leading cause of cancer-related mortality among males in North America, with an increasing morbidity in China and other Asian countries. The aim of this study was to evaluate the protein expression of autophagy-related genes Beclin-1 and LC3 in patients with prostate cancer (PCa) and benign prostatic hyperplasia (BPH) and elucidate their association with p53 and Bcl-2. The total protein of 34 PCa and 50 BPH samples was extracted and the expression of Beclin-1 and LC3 was analyzed by western blotting assay. Subsequently, a total of 96 paraffin-embedded BPH tissue samples was subdivided into 2 groups, one group in which patients had received 5α-reductase inhibitor, due to its effect of androgen ablation, and the control group, in which patients had not received the 5α-reductase inhibitor. The samples were randomly collected and examined using immunohistochemical (IHC) analysis. The western blot analysis demonstrated that Beclin-l and LC3 expression was higher in BPH tissues compared to PCa tissues (P<0.001). There was no statistically significant difference between PCas of different Gleason scores (P>0.05). The result of IHC revealed that Beclin-l and LC3 expression in the group of patients who had received the 5α-reductase inhibitor was significantly higher compared to that in the control group; however, the expression of Bcl-2 and p53 was lower (P<0.05). Beclin-1 expression exhibited a negative correlation with Bcl-2 (r=-0.402, P<0.001), whereas LC3 expression exhibited a positive correlation with Beclin-1 (r=0.345, P=0.001) and a negative correlation with Bcl-2 (r=-0.216, P=0.035). It was suggested that autophagy-related genes Beclin-l and LC3 may be involved in the development and progression of PCa. In addition, the expression of these genes was higher in patients with BPH who had received a 5α-reductase inhibitor, due to androgen reduction. As a result, the induced autophagy may reduce the risk of PCa.

Norcantharidin, derivative of cantharidin, for cancer stem cells

Cancer stem cells (CSCs) existing in human cancers have been demonstrated to be a major cause of cancer treatment resistance, invasion, metastasis, and relapse. Self-renewal pathways, Wnt/β-catenin, Sonic hedgehog (Shh), and the Notch signaling pathway play critical roles in developing CSCs and lead to angiogenesis, migration, invasion, and metastasis. Multidrug resistance (MDR) is an unfavorable factor causing the failure of treatments against cancer cells. The most important and thoroughly studied mechanism involved in MDR is the active efflux of chemotherapeutic agents through membrane drug transporters. There is growing evidence that Norcantharidin (NCTD), a water-soluble synthetic small molecule derivative of naturally occurring cantharidin from the medicinal insect blister beetle (Mylabris phalerata Pallas), is capable of chemoprevention and tumor inhibition. We summarize investigations into the modulation of self-renewal pathways and MDR in CSCs by NCTD. This review may aid in further investigation of using NCTD to develop more effective strategies for cancer treatment to reduce resistance and recurrence.

Suppressions of Migration and Invasion by Cantharidin in TSGH-8301 Human Bladder Carcinoma Cells through the Inhibitions of Matrix Metalloproteinase-2/-9 Signaling

Cancer metastasis becomes an initial cause of cancer death in human population. In many cancers, it has been shown that the high levels of matrix metalloproteinase (MMP)-2 and/or MMP-9 are associated with the invasive phenotypes of cancer cells. In this study, we investigated the effects of cantharidin, a derivative of blister beetles which is one of the traditional Chinese medicines, on the adhesion, migration, and invasion of human bladder cancer TSGH-8301 cells. Cantharidin effectively suppressed TSGH-8301 cell adhesion, migration, and invasion in a concentration-dependent manner. Results from Western blotting, RT-PCR, and gelatin zymography assays indicated that cantharidin blocked the protein levels, gene expression (mRNA), and activities of MMP-2 and -9 in TSGH-8301 cells. Cantharidin also significantly suppressed the protein expressions of p-p38 and p-JNK1/2 in TSGH-8301 cells. Taken together, cantharidin was suggested to present antimetastatic potential via suppressing the levels of MMP-2 and MMP-9 expression that might be mediated by targeting the p38 and JNK1/2 MAPKs pathway in TSGH-8301 human bladder cancer cells.

Regulation of the FOXO3a/Bim signaling pathway by 5,7-dihydroxy-8-nitrochrysin in MDA-MB-453 breast cancer cells

We previously demonstrated that 5,7-dihydroxy-8-nitrochrysin (NOC), a novel synthetic chrysin analog, preferentially inhibits HER-2/neu-overexpressing MDA-MB-453 breast cancer cell growth by inducing apoptosis; however, the precise molecular mechanism was unclear. In this study, we demonstrated that NOC significantly induces apoptosis of MDA-MB-453 cells and that this is primarily mediated through a mitochondrial death cascade. This was presented as a loss of mitochondrial membrane potential, release of cytochrome c and activation of caspase-9. NOC induces a significant increase in levels of the BH3-only protein Bim. Small interfering RNA-mediated knockdown of Bim markedly attenuated NOC-induced apoptosis. An upstream transcriptional regulator of Bim, forkhead box O3a transcription factor (FOXO3a), experienced a decrease in phosphorylation and nuclear translocation. Silencing of FOXO3a resulted in a marked attenuation in the expression of Bim, as well as protection against NOC-mediated apoptosis. Furthermore, NOC-induced activation and nuclear localization of FOXO3a was associated with reduced levels of Akt phosphorylation. These results suggest that NOC induces apoptosis in MDA-MB-453 human breast cancer cells via caspase activation and modulation of the Akt/FOXO3a pathway.

Effects of serum containing Chinese medicine Sanpi Pingwei () formula on proliferation and apoptosis of human SGC-7901 cells

OBJECTIVE

To investigate the effects of serum containing Chinese medicine (CM) Sanpi Pingwei (, SPPW) formula on the proliferation and apoptosis of human SGC-7901 cells and the possible mechanism.

METHODS

Serum containing CM SPPW formula (SPPW serum) was prepared by a serum pharmacology method. Human SGC-7901 cells were incubated with SPPW serum at three different concentrations and with the anticancer drug 5-fluorouracil (5-FU), respectively. Cell proliferation was assessed by MTT assay, and cell apoptosis was detected by flow cytometry assay. Real-time quantitative polymerase chain reaction (RT-PCR) and Western blot assay were employed to confirm the expressions of Bcl-2, Bax and p53 in SGC-7901 cells at mRNA and protein levels, respectively.

RESULTS

SPPW serum suppressed the proliferation of SGC-7901 cells in a time- and dose-dependent manner. The colony forming rate of negative control was 48.2%, while those in the three SPPW serum groups and the 5-FU group decreased significantly (P<0.01). The number of colony forming units in the SPPW high dosage group was significantly smaller than that in the 5-FU group (P<0.01). MTT assay showed that SPPW serum restrained the proliferation of SGC-7901 cells, and the inhibition rate increased significantly in a dose-dependent manner. Annexin V/PI Assay suggested that SPPW serum induced the apoptosis of SGC-7901 cells significantly. RT-PCR and western blot assay indicated that SPPW serum upregulated the protein and mRNA expression levels of Bax and p53 in SGC-7901 cells, but downregulated the protein and mRNA expressions of Bcl-2.

CONCLUSIONS

SPPW formula inhibits the proliferation of SGC-7901 cells in vitro and induces the cell apoptosis. It plays an anticancer role by regulating the expressions of Bax, p53 and Bcl-2 in SGC-7901 cells.

Norcantharidin facilitates LPS-mediated immune responses by up-regulation of AKT/NF-κB signaling in macrophages

Norcantharidin (NCTD), a demethylated analog of cantharidin, is a common used clinical drug to inhibit proliferation and metastasis of cancer cells. But the role of NCTD in modulating immune responses remains unknown. Here, we investigated the function and mechanism of NCTD in regulation of TLR4 associated immune response in macrophages. We evaluated the influence of NCTD on host defense against invaded pathogens by acute peritonitis mouse model, ELISA, Q-PCR, nitrite quantification, phagocytosis assay and gelatin zymography assay. Our data showed that the survival and the serum concentrations of IL-6 and TNF-α were all enhanced by NCTD significantly in peritonitis mouse model. Accordingly, LPS-induced cytokine, nitric oxide and MMP-9 production as well as the phagocytosis of bacteria were all up-regulated by NCTD in a dose dependent manner in both RAW264.7 cells and bone marrow-derived macrophages (BMMs). Then we further analyzed TLR4 associated signaling pathway by Western blot, Immunofluorescence and EMSA in the presence or absence of LPS. The phosphorylation of AKT and p65 at serine 536 but not serine 468 was enhanced obviously by NCTD in a dose dependent manner, whereas the degradation of IκBα was little effected. Consequently, the nuclear translocation and DNA binding ability of NF-κB was also increased by NCTD obviously in RAW264.7 cells. Our results demonstrated that NCTD could facilitate LPS-mediated immune response through promoting the phosphorylation of AKT/p65 and transcriptional activity of NF-κB, thus reprofiling the traditional anti-tumor drug NCTD as a novel immune regulator in promoting host defense against bacterial infection.