Norcantharidin, derivative of cantharidin, for cancer stem cells

Targeting the autophagy-miRNA axis in prostate cancer: toward novel diagnostic and therapeutic strategies

Since prostate cancer is one of the leading causes of cancer-related death, a better understanding of the molecular pathways guiding its development is imperative. A key factor in prostate cancer is autophagy, a cellular mechanism that affects both cell survival and death. Autophagy is essential in maintaining cellular homeostasis. Autophagy is a physiological mechanism wherein redundant or malfunctioning cellular constituents are broken down and recycled. It is essential for preserving cellular homeostasis and is implicated in several physiological and pathological conditions, including cancer. Autophagy has been linked to metastasis, tumor development, and treatment resistance in prostate cancer. The deregulation of miRNAs related to autophagy appears to be a crucial element in the etiology of prostate cancer. These miRNAs influence the destiny of cancer cells by finely regulating autophagic mechanisms. Numerous investigations have emphasized the dual function of specific miRNAs in prostate cancer, which alter autophagy-related pathways to function as either tumor suppressors or oncogenes. Notably, miRNAs have been linked to the control of autophagy and the proliferation, apoptosis, and migration of prostate cancer cells. To create customized therapy approaches, it is imperative to comprehend the dynamic interplay between autophagy and miRNAs in prostate cancer. The identification of key miRNAs provides potential diagnostic and prognostic markers. Unraveling the complex network of lncRNAs, like PCA3, also expands the repertoire of molecular targets for therapeutic interventions. This review explores the intricate interplay between autophagy and miRNAs in prostate cancer, focusing on their regulatory roles in cellular processes ranging from survival to programmed cell death.

Mechanisms of norcantharidin against renal tubulointerstitial fibrosis

Renal tubulointerstitial fibrosis (RTIF) is a common feature and inevitable consequence of all progressive chronic kidney diseases, leading to end-stage renal failure regardless of the initial cause. Although research over the past few decades has greatly improved our understanding of the pathophysiology of RTIF, until now there has been no specific treatment available that can halt the progression of RTIF. Norcantharidin (NCTD) is a demethylated analogue of cantharidin, a natural compound isolated from 1500 species of medicinal insect, the blister beetle (Mylabris phalerata Pallas), traditionally used for medicinal purposes. Many studies have found that NCTD can attenuate RTIF and has the potential to be an anti-RTIF drug. This article reviews the recent progress of NCTD in the treatment of RTIF, with emphasis on the pharmacological mechanism of NCTD against RTIF.

Downregulation of hepcidin by norcantharidin in macrophage

Norcantharidin (NCTD) is a demethylated analogue of cantharidin. It was recently demonstrated that NCTD reduces iron contents in the liver and spleen of mice in vivo, indicating that NCTD can affect iron metabolism via hepcidin. Here, we investigated the effects of NCTD on expression of iron storage protein ferritin-light chain (Ft-L), transferrin receptor 1 (TfR1), divalent metal transporter 1 (DMT1), ferroportin 1 (Fpn1), hepcidin, iron regulatory protein 1 (IRP1), IL-6, p-JAK2 and p-STAT3 in lipopolysaccharides (LPS)-treated RAW264.7 cells in vitro via Real-time PCR and Western blotting analysis. We demonstrate that NCTD down-regulates Ft-L, hepcidin, IL-6, pJAK2, pSTAT3 and up-regulates TfR1, DMT1, Fpn1 and IRP1 expression in LPS treated cells, showing that NCTD can inhibit hepcidin via the IL-6/JAK2/STAT3 signalling pathway and also increase TfR1, DMT1 and Fpn1 expression via down-regulating hepcidin and up-regulating IRP1. Our findings provide further evidence in vitro for the role of NCTD in iron metabolism.

The novel norcantharidin derivative DCZ5417 suppresses multiple myeloma progression by targeting the TRIP13-MAPK-YWHAE signaling pathway

BACKGROUND

Multiple myeloma (MM), an incurable disease owing to drug resistance, requires safe and effective therapies. Norcantharidin (NCTD), an active ingredient in traditional Chinese medicines, possesses activity against different cancers. However, its toxicity and narrow treatment window limit its clinical application. In this study, we synthesized a series of derivatives of NCTD to address this. Among these compounds, DCZ5417 demonstrated the greatest anti-MM effect and fewest side effects. Its anti-myeloma effects and  the mechanism were further tested.

METHODS

Molecular docking, pull-down, surface plasmon resonance-binding, cellular thermal shift, and ATPase assays were used to study the targets of DCZ5417. Bioinformatic, genetic, and pharmacological approaches were used to elucidate the mechanisms associated with DCZ5417 activity.

RESULTS

We confirmed a highly potent interaction between DCZ5417 and TRIP13. DCZ5417 inhibited the ATPase activity of TRIP13, and its anti-MM activity was found to depend on TRIP13. A mechanistic study verified that DCZ5417 suppressed cell proliferation by targeting TRIP13, disturbing the TRIP13/YWHAE complex and inhibiting the ERK/MAPK signaling axis. DCZ5417 also showed a combined lethal effect with traditional anti-MM drugs. Furthermore, the tumor growth-inhibitory effect of DCZ5417 was demonstrated using in vivo tumor xenograft models.

CONCLUSIONS

DCZ5417 suppresses MM progression in vitro, in vivo, and in primary cells from drug-resistant patients, affecting cell proliferation by targeting TRIP13, destroying the TRIP13/YWHAE complex, and inhibiting ERK/MAPK signaling. These results imply a new and effective therapeutic strategy for MM treatment.

Norcantharidin-Encapsulated C60-Modified Nanomicelles: A Potential Approach to Mitigate Cytotoxicity in Renal Cells and Simultaneously Enhance Anti-Tumor Activity in Hepatocellular Carcinoma Cells

OBJECTIVE

The objective of this study was to examine the preparation process of DSPE-PEG-C60/NCTD micelles and assess the impact of fullerenol (C60)-modified micelles on the nephrotoxicity and antitumor activity of NCTD.

METHOD

The micelles containing NCTD were prepared using the ultrasonic method and subsequently optimized and characterized. The cytotoxicity of micelles loaded with NCTD was assessed using the CCK-8 method on human hepatoma cell lines HepG2 and BEL-7402, as well as normal cell lines HK-2 and L02. Acridine orange/ethidium bromide (AO/EB) double staining and flow cytometry were employed to assess the impact of NCTD-loaded micelles on the apoptosis of the HK-2 cells and the HepG2 cells. Additionally, JC-1 fluorescence was utilized to quantify the alterations in mitochondrial membrane potential. The generation of reactive oxygen species (ROS) following micelle treatment was determined through 2',7'-dichlorofluorescein diacetate (DCFDA) staining.

RESULTS

The particle size distribution of the DSPE-PEG-C60/NCTD micelles was determined to be 91.57 nm (PDI = 0.231). The zeta potential of the micelles was found to be -13.8 mV. The encapsulation efficiency was measured to be 91.9%. The in vitro release behavior of the micelles followed the Higuchi equation. Cellular experiments demonstrated a notable decrease in the toxicity of the C60-modified micelles against the HK-2 cells, accompanied by an augmented inhibitory effect on cancer cells. Compared to the free NCTD group, the DSPE-PEG-C60 micelles exhibited a decreased apoptosis rate (12%) for the HK-2 cell line, lower than the apoptosis rate observed in the NCTD group (36%) at an NCTD concentration of 75 μM. The rate of apoptosis in the HepG2 cells exhibited a significant increase (49%), surpassing the apoptosis rate observed in the NCTD group (24%) at a concentration of 150 μM NCTD. The HK-2 cells exhibited a reduction in intracellular ROS and an increase in mitochondrial membrane potential (ΔψM) upon exposure to C60-modified micelles compared to the NCTD group.

CONCLUSIONS

The DSPE-PEG-C60/NCTD micelles, as prepared in this study, demonstrated the ability to decrease cytotoxicity and ROS levels in normal renal cells (HK-2) in vitro. Additionally, these micelles showed an enhanced antitumor activity against human hepatocellular carcinoma cells (HepG2, BEL-7402).

Traditional Chinese medicine for colorectal cancer treatment: potential targets and mechanisms of action

Colorectal cancer (CRC) is a disease with complex pathogenesis, it is prone to metastasis, and its development involves abnormalities in multiple signaling pathways. Surgery, chemotherapy, radiotherapy, target therapy, and immunotherapy remain the main treatments for CRC, but improvement in the overall survival rate and quality of life is urgently needed. Traditional Chinese medicine (TCM) has a long history of preventing and treating CRC. It could affect CRC cell proliferation, apoptosis, cell cycle, migration, invasion, autophagy, epithelial-mesenchymal transition, angiogenesis, and chemoresistance by regulating multiple signaling pathways, such as PI3K/Akt, NF-κB, MAPK, Wnt/β-catenin, epidermal growth factor receptors, p53, TGF-β, mTOR, Hedgehog, and immunomodulatory signaling pathways. In this paper, the main signaling pathways and potential targets of TCM and its active ingredients in the treatment of CRC were systematically summarized, providing a theoretical basis for treating CRC with TCM and new ideas for further exploring the pathogenesis of CRC and developing new anti-CRC drugs.

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

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

Review targeted drug delivery systems for norcantharidin in cancer therapy

Norcantharidin (NCTD) is a demethylated derivative of cantharidin (CTD), the main anticancer active ingredient isolated from traditional Chinese medicine Mylabris. NCTD has been approved by the State Food and Drug Administration for the treatment of various solid tumors, especially liver cancer. Although NCTD greatly reduces the toxicity of CTD, there is still a certain degree of urinary toxicity and organ toxicity, and the poor solubility, short half-life, fast metabolism, as well as high venous irritation and weak tumor targeting ability limit its widespread application in the clinic. To reduce its toxicity and improve its efficacy, design of targeted drug delivery systems based on biomaterials and nanomaterials is one of the most feasible strategies. Therefore, this review focused on the studies of targeted drug delivery systems combined with NCTD in recent years, including passive and active targeted drug delivery systems, and physicochemical targeted drug delivery systems for improving drug bioavailability and enhancing its efficacy, as well as increasing drug targeting ability and reducing its adverse effects.

Graphical Abstract

Efficacy of Aidi Injection Combined With Radiotherapy for the Treatment of Nasopharyngeal Carcinoma: A Systematic Review and Meta-Analysis

Objective: Radiotherapy (RT) is the first choice in the treatment of nasopharyngeal carcinoma (NPC) but there are many adverse reactions. There is evidence that Aidi injection can improve the effect of RT and reduce the occurrence of adverse reactions after RT, but there is still a lack of evidence-based study. The objective of this study was to evaluate the efficacy and safety of Aidi injection combined with RT in the treatment of NPC. Methods: The PubMed, Cochrane Library, CNKI, EMBASE, Web of Science, CBM, Wanfang, and VIP data were thoroughly searched for randomized controlled trials (RCTs) on Aidi injection combined with RT against NPC until February 2021. The literature was screened, extracted, and evaluated by 2 investigators independently. Meta-analysis was performed by RevMan5.3 and Stata 14.0, and the quality of evidence was evaluated by Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Results: In this study, we included 9 RCT studies involving 422 patients. The results showed significant between-group differences in complete remission rate (CRR) [relative risk (RR) = 1.17, 95% CI (1.04, 1.31), P = .009], Karnofsky Performance Status Scale (KPS) score [RR = 1.30, 95% CI (1.19, 1.42), P < .00001], leukopenia [RR = 0.65, 95% CI (0.54, 0.78), P < .00001], hemoglobin reduction [RR = 0.60, 95% CI (0.43, 0.84), P = .003], nausea and vomiting [RR = 0.60, 95% CI (0.45, 0.80), P = .0004], oropharyngeal mucosa injury (OMI) [RR = 0.25, 95% CI (0.15, 0.44), P < .00001], but the differences were not statistically significant in total effective rate (TER) [RR = 1.03, 95% CI (0.98, 1.08), P = .20 > 0.05], thrombocytopenia [RR = 0.78, 95%CI (0.52,1.16), P = .22 > .05], and skin injury [RR = 0.81, 95% CI (0.64, 1.04), P = .1 > .05]. Conclusion: Aidi injection combined with RT can improve patients’ quality of life (KPS score) and reduce the adverse reactions caused by RT (such as leukopenia, hemoglobin reductio，OMI，nausea, and vomiting). However, limited by the quality and quantity of the included trials，more high-quality studies should be performed to verify our conclusions.

Wnt-β-catenin Signaling Pathway, the Achilles' Heels of Cancer Multidrug Resistance

BACKGROUND

Most of the anticancer chemotherapies are hampered via the development of multidrug resistance (MDR), which is the resistance of tumor cells against cytotoxic effects of multiple chemotherapeutic agents. Overexpression and/or over-activation of ATP-dependent drug efflux transporters is a key mechanism underlying MDR development. Moreover, enhancement of drug metabolism, changes in drug targets and aberrant activation of the main signaling pathways, including Wnt, Akt and NF-κB are also responsible for MDR.

METHODS

In this study, we have reviewed the roles of Wnt signaling in MDR as well as its potential therapeutic significance. Pubmed and Scopus have been searched using Wnt, β-catenin, cancer, MDR and multidrug resistance as keywords. The last search was done in March 2019. Manuscripts investigating the roles of Wnt signaling in MDR or studying the modulation of MDR through the inhibition of Wnt signaling have been involved in the study. The main focus of the manuscript is regulation of MDR related transporters by canonical Wnt signaling pathway.

RESULT AND CONCLUSION

Wnt signaling has been involved in several pathophysiological states, including carcinogenesis and embryonic development. Wnt signaling is linked to various aspects of MDR including P-glycoprotein and multidrug resistance protein 1 regulation through its canonical pathways. Aberrant activation of Wnt/β- catenin signaling leads to the induction of cancer MDR mainly through the overexpression and/or over-activation of MDR related transporters. Accordingly, Wnt/β-catenin signaling can be a potential target for modulating cancer MDR.

Contribution of p38 MAPK Pathway to Norcantharidin-Induced Programmed Cell Death in Human Oral Squamous Cell Carcinoma

Norcantharidin (NCTD), a demethylated analog of cantharidin isolated from blister beetles, has been used as a promising anticancer agent; however, the underlying function of NCTD against human oral squamous cell carcinoma (OSCC) has not been fully understood. Here, this study was aimed to investigate the apoptotic effect and molecular targets of NCTD in human OSCC in vitro and in vivo. The anticancer effects of NCTD and its related molecular mechanisms were evaluated by trypan blue exclusion assay, live/dead assay, western blotting, 4-6-Diamidino-2-Phenylindole (DAPI) staining, flow cytometric analysis, Terminal Deoxynucleotidyl Transferase dUTP Nick end Labeling (TUNEL) assay, and immunohistochemistry. NCTD significantly inhibited cell growth and increased the number of dead cells in HSC-3 and HN22 cell lines. It induced the following apoptotic phenomena: (1) the cleavages of poly (ADP-ribose) polymerase and casepase-3; (2) increase in apoptotic morphological changes (nuclear condensation and fragmentation); (3) increase in annexin V-positive cells or sub-G₁ population of cells. NCTD significantly activated the p38 mitogen-activated protein kinase (MAPK) pathway but inactivated the signal transducer and activator of transcription (STAT)3 pathway. A p38 MAPK inhibitor (SB203580) partially attenuated NCTD-induced programmed cell death (apoptosis) in both cell lines, whereas ectopic overexpression of STAT3 did not affect it. NCTD strongly suppressed tumor growth in the tumor xenograft bearing HSC-3 cells, and the number of TUNEL-positive cells increased in NCTD-treated tumor tissues. In addition, NCTD did not cause any histopathological changes in the liver nor the kidney. NCTD induced programmed cell death via the activation of p38 MAPK in OSCC. Therefore, these results suggest that NCTD could be a potential anticancer drug candidate for the treatment of OSCC.

Norcantharidin regulates ERα signaling and tamoxifen resistance via targeting miR-873/CDK3 in breast cancer cells

MiR-873/CDK3 has been shown to play a critical role in ERα signaling and tamoxifen resistance. Thus, targeting this pathway may be a potential therapeutic approach for the treatment of ER positive breast cancer especially tamoxifen resistant subtype. Here we report that Norcantharidin (NCTD), currently used clinically as an ani-cancer drug in China, regulates miR-873/CDK3 axis in breast cancer cells. NCTD decreases the transcriptional activity of ERα but not ERβ through the modulation of miR-873/CDK3 axis. We also found that NCTD inhibits cell proliferation and tumor growth and miR-873/CDK3 axis mediates cell proliferation suppression of NCTD. More important, we found that NCTD sensitizes resistant cells to tamoxifen. NCTD inhibits tamoxifen induced the transcriptional activity as well ERα downstream gene expressions in tamoxifen resistant breast cancer cells. In addition, we found that NCTD restores tamoxifen induced recruitments of ERα co-repressors N-CoR and SMRT. Knockdown of miR-873 and overexpression of CDK3 diminish the effect of NCTD on tamoxifen resistance. Our data shows that NCTD regulates ERα signaling and tamoxifen resistance by targeting miR-873/CDK3 axis in breast cancer cells. This study may provide an alternative therapy strategy for tamoxifen resistant breast cancer.

Norcantharidin Suppresses YD-15 Cell Invasion Through Inhibition of FAK/Paxillin and F-Actin Reorganization

Norcantharidin (NCTD), a demethylated derivative of cantharidin, has been reported to exhibit activity against various types of cancers. However, the anti-invasive effects of NCTD and its molecular mechanism in human mucoepidermoid carcinoma (MEC) remain incompletely elucidated. Clonogenic, wound healing, invasion, zymography, western blotting and immunocytochemistry assays were performed in YD-15 cells to investigate the anti-invasive effect of NCTD and its molecular mechanism of action. The inhibitory effects of NCTD on invasiveness were compared with those of a novel focal adhesion kinase (FAK) kinase inhibitor, PF-562271. NCTD markedly suppressed the colony formation, migration, and invasion of YD-15 cells as well as the activities of MMP-2 and MMP-9. It disrupted F-actin reorganization through suppressing the FAK/Paxillin axis. Moreover, NCTD exhibited a powerful anti-invasive effect compared with that of PF-562271 in YD-15 cells. Collectively, these results suggest that NCTD has a potential anti-invasive activity against YD-15 cells. This study may clarify the impact of NCTD on migration and invasion of human MEC cells.

Norcantharidin reverses cisplatin resistance and inhibits the epithelial mesenchymal transition of human non‑small lung cancer cells by regulating the YAP pathway

Non-small cell lung cancer (NSCLC) accounts for >80% of all lung cancer cases, which are the leading cause of cancer-related mortality worldwide. The clinical efficacy of available therapies for NSCLC is often limited due to the development of resistance to anticancer drugs, particularly to cisplatin (DDP). Norcantharidin (NCTD) is a traditional Chinese medicine used in the treatment of many types of cancer, to which patients do not develop resistance. The aim of the present study was to examine the potential synergistic effects of NCTD and DPP on the viability of the the DDP-resistant NSCLC cell line, A549/DDP. We further explored the potential underlying mechanisms by examining the expression of the oncogene, Yes-associated protein 1 (YAP), whose activation was recently found to be associated with drug resistance. We further examined a series of human lung cancer cell lines and tissues from patients with lung cancer, which revealed that YAP activation contributed to lung cancer initiation, progression and metastasis, and was associated with a poor prognosis, and confering resistance against targeted therapies. Moreover, YAP expression was evaluated in the A549/DDP cells treated with NCTD, DDP, or both drugs. The combined treatment significantly sensitized the A549/DDP cells to DDP-induced growth inhibition by reducing YAP promoter activity (based on transcriptional expression) and the expression of its target genes, connective tissue growth factor (CTGF) and cysteine rich angiogenic inducer 61 (CYR61). Furthermore, compared to the individual treatments, combined treatment increased cell apoptosis and senescence, and decreased epithelial-to-mesenchymal transition and the cell migratory and invasive ability. On the whole, our data indicate that the application of NCTD with reverses DDP resistance and thus, this combined treatment may have promising prospects for use in improving the outcome of patients with NSCLC.

Norcantharidin, a clinical used chemotherapeutic agent, acts as a powerful inhibitor by interfering with fibrinogen-integrin αIIb β3 binding in human platelets

During platelet activation, fibrinogen binds to its specific platelet receptor, integrin α_IIb β₃ , thus completing the final common pathway for platelet aggregation. Norcantharidin (NCTD) is a promising anticancer agent in China from medicinal insect blister beetle. In this study, we provided the evidence to demonstrate NCTD (0.1-1.0 μM) possesses very powerful antiplatelet activity in human platelets; nevertheless, it had no effects on surface P-selectin expression and only slight inhibition on ATP-release reaction in activated platelets. Moreover, NCTD markedly hindered integrin α_IIb β₃ activation by interfering with the binding of FITC-labelled PAC-1. It also markedly reduced the number of adherent platelets and the single platelet spreading area on immobilized fibrinogen as well as clot retraction. Additionally, NCTD attenuated phosphorylation of proteins such as integrin β₃ , Src and FAK in platelets spreading on immobilized fibrinogen. These results indicate that NCTD restricts integrin α_IIb β₃ -mediated outside-in signalling in human platelets. Besides, NCTD substantially prolonged the closure time in human whole blood and increased the occlusion time of thrombotic platelet plug formation and prolonged the bleeding time in mice. In conclusion, NCTD has dual activities, it can be a chemotherapeutic agent for cancer treatment, and the other side it possesses powerful antiplatelet activity for treating thromboembolic disorders.

Mantle cell lymphoma in the era of precision medicine-diagnosis, biomarkers and therapeutic agents

Despite advances in the development of clinical agents for treating Mantle Cell Lymphoma (MCL), treatment of MCL remains a challenge due to complexity and frequent relapse associated with MCL. The incorporation of conventional and novel diagnostic approaches such as genomic sequencing have helped improve understanding of the pathogenesis of MCL, and have led to development of specific agents targeting signaling pathways that have recently been shown to be involved in MCL. In this review, we first provide a general overview of MCL and then discuss about the role of biomarkers in the pathogenesis, diagnosis, prognosis, and treatment for MCL. We attempt to discuss major biomarkers for MCL and highlight published and ongoing clinical trials in an effort to evaluate the dominant signaling pathways as drugable targets for treating MCL so as to determine the potential combination of drugs for both untreated and relapse/refractory cases. Our analysis indicates that incorporation of biomarkers is crucial for patient stratification and improve diagnosis and predictability of disease outcome thus help us in designing future precision therapies. The evidence indicates that a combination of conventional chemotherapeutic agents and novel drugs designed to target specific dysregulated signaling pathways can provide the effective therapeutic options for both untreated and relapse/refractory MCL.

Insects: an underrepresented resource for the discovery of biologically active natural products

Nature has been the source of life-changing and -saving medications for centuries. Aspirin, penicillin and morphine are prime examples of Nature׳s gifts to medicine. These discoveries catalyzed the field of natural product drug discovery which has mostly focused on plants. However, insects have more than twice the number of species and entomotherapy has been in practice for as long as and often in conjunction with medicinal plants and is an important alternative to modern medicine in many parts of the world. Herein, an overview of current traditional medicinal applications of insects and characterization of isolated biologically active molecules starting from approximately 2010 is presented. Insect natural products reviewed were isolated from ants, bees, wasps, beetles, cockroaches, termites, flies, true bugs, moths and more. Biological activities of these natural products from insects include antimicrobial, antifungal, antiviral, anticancer, antioxidant, anti-inflammatory and immunomodulatory effects.

Sonic hedgehog, Wnt, and brain-derived neurotrophic factor cell signaling pathway crosstalk: potential therapy for depression

There are various theories to explain the pathophysiology of depression and support its diagnosis and treatment. The roles of monoamines, brain-derived neurotrophic factor (BDNF), and Wnt signaling are well researched, but sonic hedgehog (Shh) signaling and its downstream transcription factor Gli1 are not well studied in depression. Shh signaling plays a fundamental role in embryonic development and adult hippocampal neurogenesis and also involved in the growth of cancer. In this article, we summarize the evidence for the Shh signaling pathway in depression and the potential crosstalk of Shh with Wnt and BDNF. Antidepressants are known to upregulate the adult hippocampal neurogenesis to treat depression. Shh plays an important role in adult hippocampal neurogenesis, and its downstream signaling components regulate the synthesis of Wnt proteins. Moreover, the expression of Gli1 and Smo is downregulated in depression. BDNF and Wnt signaling are also regulated by various available antidepressants, so there is the possibility that Shh may be involved in the pathophysiology of depression. Therefore, the crosstalk between the Shh, Wnt, and BDNF signaling pathways is being discussed to identify the potential targets. Specifically, the potential role of the Shh signaling pathway in depression is explored as a new target for better therapies for depression.

Targeting acute myeloid leukemia stem cell signaling by natural products

Acute myeloid leukemia (AML) is the most commonly diagnosed leukemia in adults (25%) and comprises 15-20% in children. It is a genetically heterogeneous aggressive disease characterized by the accumulation of somatically acquired genetic changes, altering self-renewal, proliferation, and differentiation of hematopoietic progenitor cells, resulting in uncontrolled clonal proliferation of malignant progenitor myeloid cells in the bone marrow, peripheral blood, and occasionally in other body tissues. Treatment with modern chemotherapy regimen (cytarabine and daunorubicin) usually achieves high remission rates, still majority of patients are found to relapse, resulting in only 40-45% overall 5 year survival in young patients and less than 10% in the elderly AML patients. The leukemia stem cells (LSCs) are characterized by their unlimited self-renewal, repopulating potential and long residence in a quiescent state of G0/G1 phase. LSCs are considered to have a pivotal role in the relapse and refractory of AML. Therefore, new therapeutic strategies to target LSCs with limited toxicity towards the normal hematopoietic population is critical for the ultimate curing of AML. Ongoing research works with natural products like parthenolide (a natural plant extract derived compound) and its derivatives, that have the ability to target multiple pathways that regulate the self-renewal, growth and survival of LSCs point to ways for a possible complete remission in AML. In this review article, we will update and discuss various natural products that can target LSCs in AML.

Norcantharidin Inhibits cell growth by suppressing the expression and phosphorylation of both EGFR and c-Met in human colon cancer cells

BACKGROUND

Norcantharidin (NCTD) is a Chinese FDA approved, chemically synthesized drug for cancer treatment. The effect of NCTD on signaling proteins of EGFR and c-Met was systematically elucidated in current study.

METHODS

Two human colon cancer cell lines, HCT116 and HT29, were used as model systems to investigate the anti-cancer molecular mechanism of NCTD. Cell cycle arrest and early/late apoptosis were analyzed by flow cytometry. The levels of EGFR, phospho-EGFR, c-Met, phospho-c-Met and other related proteins were quantified by western blot analysis.

RESULTS

NCTD induced cell cycle arrest at G2/M phase in both cell lines. The early and late apoptosis was also observed. Further investigation indicated that NCTD suppressed not only the expression of the total EGFR and the phosphorylated EGFR but also the expression of the total c-Met and the phosphorylated c-Met in colon cancer cells. Moreover, EGFR expression could be mostly restored by co-treatment with MG132, a proteasome inhibitor. In addition, NCTD-induced cell death was comparable to that of the anti-cancer drug gefitinib, a tyrosine kinase inhibitor for EGFR, based on the immunoblot analysis of the expressed proteins after the drug treatment.

CONCLUSIONS

NCTD might be a useful and inexpensive drug candidate to substitute for gefitinib to serve the treatment needs of cancer patients.

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.

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.

Amphiphilic nanoparticles of resveratrol-norcantharidin to enhance the toxicity in zebrafish embryo

Direct coupling of a hydrophobic drug and a hydrophilic natural product via an ester bond produced an amphiphilic adduct that formed liposomes. Liposomes of resveratrol-norcantharidin adduct are capable of forming a tadpole-like nanoparticle and exhibited high toxicity in zebrafish embryos to give the better transportation and the effective concentration into cells. Using fluorescent chromophore showed the liposome in the stomach and intestinal villi rather than in the skin and muscle. This result may provide an insight into the mechanism of action of traditional Chinese medicines, which often contain a significant amount of flavonoids and polyphenol analogs.

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.

New Norcantharidin Analogs: Synthesis and Anticancer Activity

The reaction of direct condensation between S-ethyl-N-(7-oxabicyclo-[2.2.1]heptane-2,3-dicarbonyl)isothiosemicarbazide (1) and primary amines was used for synthesizing new N-substituted amides of 3-(3-ethylthio-1,2,4-triazol-5-yl)-7-oxabicyclo-[2.2.1]heptane-2-carboxylic acid (2-12) as norcantharadin analogs. Moreover, the anticancer activity of the obtained compounds was studied. Among all compounds, the N-3-methylbutyl amide of 3-(3-ethylthio-1,2,4-triazol-5-yl)-7-oxabicyclo-[2.2.1]heptane-2-carboxylic acid (4) presented selective in vitro toxic and antiproliferative effects against the human hepatoma cell line Hep3B, without affecting normal human liver stellate cells (LX-2 cell line).

Repurposing the antipsychotic trifluoperazine as an antimetastasis agent

Because cancer cell invasion is a critical determinant of metastasis, targeting invasion is a viable approach to prevent metastasis. Utilizing a novel three-dimensional high-throughput invasion assay, we screened a National Cancer Institute compound library and discovered compounds demonstrating inhibitory effects on cancer cell invasion. One hit, trifluoperazine, suppresses invasion of human cancer cell lines while displaying a limited cytotoxicity profile. This inhibition is due to the interference with cancer cell migratory ability but not proteolytic activity. Treatment of cancer cells with trifluoperazine significantly reduces angiogenesis and prevents cancer cell invasion through a chorioallantoic basement membrane. Mechanistically, treatment results in decreased phosphorylated AKT (Ser(473) and Thr(308)) and β-catenin (Ser(552)). Lack of phosphorylation of Ser(552) of β-catenin prevents β-catenin nuclear relocation, resulting in decreased expression of vascular endothelial growth factor, likely mediated through dopamine receptor D2. Taken together, we demonstrated that trifluoperazine is responsible for reducing the angiogenic and invasive potential of aggressive cancer cells through dopamine receptor D2 to modulate the β-catenin pathway and propose that trifluoperazine may be used as an antimetastasis chemotherapeutic.

Helminthes and insects: maladies or therapies

By definition, parasites cause harm to their hosts. But, considerable evidence from ancient traditional medicine has supported the theory of using parasites and their products in treating many diseases. Maggots have been used successfully to treat chronic, long-standing, infected wounds which failed to respond to conventional treatment by many beneficial effects on the wound including debridement, disinfection, and healing enhancement. Maggots are also applied in forensic medicine to estimate time between the death and discovery of a corpse and in entomotoxicology involving the potential use of insects as alternative samples for detecting drugs and toxins in death investigations. Leeches are segmented invertebrates, famous by their blood-feeding habits and used in phlebotomy to treat various ailments since ancient times. Leech therapy is experiencing resurgence nowadays in health care principally in plastic and reconstructive surgery. Earthworms provide a source of medicinally useful products with potential antimicrobial, antiviral, and anticancer properties. Lumbrokinases are a group of fibrinolytic enzymes isolated and purified from earthworms capable of degrading plasminogen-rich and plasminogen-free fibrin and so can be used to treat various conditions associated with thrombotic diseases. Helminth infection has been proved to have therapeutic effects in both animal and human clinical trials with promising evidence in treating many allergic diseases and can block the induction of or reduce the severity of some autoimmune disorders as Crohn's disease or ulcerative colitis. What is more, venomous arthropods such as scorpions, bees, wasps, spiders, ants, centipedes, snail, beetles, and caterpillars. The venoms and toxins from these arthropods provide a promising source of natural bioactive compounds which can be employed in the development of new drugs to treat diseases as cancer. The possibility of using these active molecules in biotechnological processes can make these venoms and toxins a valuable and promising source of natural bioactive compounds. The therapeutic use of helminthes and insects will be of great value in biomedicine and further studies on insect toxins will contribute extensively to the development of Biomedical Sciences.

The therapeutic potential of targeting the epithelial-mesenchymal transition in cancer

INTRODUCTION

The process of epithelial-to-mesenchymal transition (EMT) has long been advocated as a process during tumor progression and the acquisition of metastatic potential of human cancers. EMT has also been linked with resistance to cancer therapies.

AREAS COVERED

Basic research has provided evidence connecting EMT to increased invasion, angiogenesis and metastasis of cancer cells. A number of signaling pathways such as notch, wnt, hedgehog and PI3K-AKT, and various other individual factors therein, have been intricately connected to the onset of EMT. Here, we provide latest updates on the evidences that further highlight an association between various signaling pathways and EMT, with a focus on therapeutic targets that may have the potential to reverse EMT.

EXPERT OPINION

Our understanding of EMT and its underlying causes is rapidly evolving and a number of putative targets have been identified. It is crucial, now than ever before, to design novel translational and clinical studies for the benefit of advanced stage cancer patients with metastatic disease.

A novel cantharidin analog N-benzylcantharidinamide reduces the expression of MMP-9 and invasive potentials of Hep3B via inhibiting cytosolic translocation of HuR

Invasion and metastasis are major causes of malignant tumor-associated mortality. The present study aimed to investigate the molecular events underlying inhibitory effect of N-benzylcantharidinamide, a novel synthetic analog of cantharidin, on matrix metalloproteinase-9 (MMP-9)-mediated invasion in highly metastatic hepatocellular carcinoma Hep3B cells. In this investigation, among six analogs of cantharidin, only N-benzylcantharidinamide has the inhibitory action on MMP-9 expression at non-toxic dose. The MMP-9 expression and invasion of Hep3B cells were significantly suppressed by treatment of N-benzylcantharidinamide in a dose-dependent manner. On the other hand, the transcriptional activity of MMP-9 promoter and nuclear levels of NF-κB and AP-1 as the main transcriptional factors inducing MMP-9 expression were not affected by it although the level of MMP-9 mRNA was reduced by treatment of N-benzylcantharidinamide. Interestingly, the stability of MMP-9 mRNA was significantly reduced by N-benzylcantharidinamide-treatment. In addition, the cytosolic translocation of human antigen R (HuR), which results in the increase of MMP-9 mRNA stability through interaction of HuR with 3'-untranslated region of MMP-9 mRNA, was suppressed by treatment of N-benzylcantharidinamide, in a dose-dependent manner. Taken together, it was demonstrated, for the first time, that N-benzylcantharidinamide suppresses MMP-9 expression by reducing HuR-mediated MMP-9 mRNA stability for the inhibition of invasive potential in highly metastatic Hep3B cells.