Norcantharidin Inhibits SK-N-SH Neuroblastoma Cell Growth by Induction of Autophagy and Apoptosis

Functional hydrogels for hepatocellular carcinoma: therapy, imaging, and in vitro model

Hepatocellular carcinoma (HCC) is among the most common malignancies worldwide and is characterized by high rates of morbidity and mortality, posing a serious threat to human health. Interventional embolization therapy is the main treatment against middle- and late-stage liver cancer, but its efficacy is limited by the performance of embolism, hence the new embolic materials have provided hope to the inoperable patients. Especially, hydrogel materials with high embolization strength, appropriate viscosity, reliable security and multifunctionality are widely used as embolic materials, and can improve the efficacy of interventional therapy. In this review, we have described the status of research on hydrogels and challenges in the field of HCC therapy. First, various preparation methods of hydrogels through different cross-linking methods are introduced, then the functions of hydrogels related to HCC are summarized, including different HCC therapies, various imaging techniques, in vitro 3D models, and the shortcomings and prospects of the proposed applications are discussed in relation to HCC. We hope that this review is informative for readers interested in multifunctional hydrogels and will help researchers develop more novel embolic materials for interventional therapy of HCC.

Pentoxifylline and Norcantharidin Modify p62 Expression in 2D and 3D Cultures of B16F1 Cells

Three-dimensional cell cultures have improved the evaluation of drugs for cancer therapy, due to their high similarity to solid tumors. In melanoma, autophagy appears to show a dual role depending on the progression of the disease. p62 protein has been proposed for the evaluation of autophagic flux since its expression is an indicator of the state of autophagy. Pentoxifylline (PTX) and Norcantharidin (NCTD) are drugs that have been shown to possess anticancer effects. In this work, we used B16F1 mouse melanoma cells in two-dimensional (2D) monolayer cultures and three-dimensional (3D) spheroids to test the effect of PTX and NCTD over the p62 expression. We analyzed the effect on p62 expression through Western blot and immunofluorescence assays. Our results indicate that PTX decreases p62 expression in both cell culture models, while Norcantharidin increases its expression in 3D cultures at 24 h. Therefore, these drugs could have a potential therapeutic use for the regulation of autophagy in melanoma, depending on the state of evolution of the disease.

Intratumoral injection of norcantharidin liposome emulsion hybrid delivery system amplifies the cancer-fighting effects of oral sorafenib against hepatocellular carcinoma

Interventional therapies are increasingly used in clinical trials for hepatocellular carcinoma (HCC). Sorafenib is the front-line remedy for HCC, however, chemoresistance occurs immutably and affects the effectiveness of treatment. In a previous study, a norcantharidin liposome emulsion hybrid (NLEH) delivery system for HCC was developed. This study aims to examine the therapeutic effects of the combination of intratumoral injection of NLEH and sorafenib in treating HCC. Sorafenib combined with NLEH activated the apoptosis pathway by synergistically upregulating caspase-9, promoting cytotoxicity, apoptosis (64.57%), and G2/M cell cycle arrest (48.96%). Norcantharidin could alleviate sorafenib resistance by counteracting sorafenib-induced phosphorylation of Akt. Additionally, intratumoral injection of NLEH exhibited a sustained accumulation in the tumor within 24 h and didn't distribute to other major organs. Intratumoral injection of NLEH in combination with oral sorafenib displayed the most potent tumor growth inhibitory effect (77.91%) in vivo. H&E staining results and the indicators of the renal and liver function tests demonstrated the safety of this combination therapy. Overall, these results showed that intratumoral injection of NLEH in combination with oral sorafenib treatment represented a rational potential therapeutic option for HCC.

Strategies for Solubility and Bioavailability Enhancement and Toxicity Reduction of Norcantharidin

Cantharidin (CTD) is the main active ingredient isolated from Mylabris, and norcantharidin (NCTD) is a demethylated derivative of CTD, which has similar antitumor activity to CTD and lower toxicity than CTD. However, the clinical use of NCTD is limited due to its poor solubility, low bioavailability, and toxic effects on normal cells. To overcome these shortcomings, researchers have explored a number of strategies, such as chemical structural modifications, microsphere dispersion systems, and nanodrug delivery systems. This review summarizes the structure-activity relationship of NCTD and novel strategies to improve the solubility and bioavailability of NCTD as well as reduce the toxicity. This review can provide evidence for further research of NCTD.

Norcantharidin Induces Immunogenic Cell Death of Bladder Cancer Cells through Promoting Autophagy in Acidic Culture

The acidic tumor microenvironment stands as a major obstacle to the efficient elimination of tumor cells. Norcantharidin (NCTD) is a powerful antitumor agent with multiple bioactivities. However, the effect of NCTD under acidic conditions is still unclear. Here, we report that NCTD can efficiently kill bladder cancer (BC) cells in acidic culture, and more intriguingly, NCTD can induce immunogenic cell death (ICD), thereby promoting antitumor immunity. In NCTD-treated BC cells, the surface-exposed calreticulin (ecto-CALR) was significantly increased. Consistently, co-culture with these cells promoted dendritic cell (DC) maturation. The NCTD-induced ICD is autophagy dependent, as autophagy inhibition completely blocked the NCTD-induced ecto-CALR and DC maturation. In addition, the DC showed a distinct maturation phenotype (CD80^high CD86^low) in acidic culture, as compared to that in physiological pH (CD⁸⁰ high CD86^high). Finally, the NCTD-induced ICD was validated in a mouse model. NCTD treatment significantly increased the tumor-infiltrating T lymphocytes in MB49 bladder cancer mice. Immunizing mice with NCTD-treated MB49 cells significantly increased tumor-free survival as compared to control. These findings demonstrate that NCTD could induce ICD in an acidic environment and suggest the feasibility to combine NCTD with anticancer immunotherapy to treat BC.

Micelles in Cancer Therapy: An Update on Preclinical and Clinical Status

BACKGROUND

In the recent years, Micelles represent a promising carrier for the treatment and diagnosis of cancer. Architecturally, micelles are self-assembled nanosized colloidal aggregates prepared from amphiphilic surfactant with a hydrophobic core and hydrophilic shell. Such a composition makes them a potential carrier for delivery of hydrophobic anticancer drugs with in their core.

METHODS

Micelles have received increasing interest as an enhanced permeability and retention (EPR) targeted drug delivery systems for cancer treatment. Micelles can be modified to contribute various attractive properties, for instance, active targeting, stimuli-responsiveness. They have also proven their ability in drug targeting to tumor tissue, enhanced drug accumulation, drug stabilization, tissue penetration, prolong circulation, in vivo biocompatibility, biodegradability and reduced side effects. Micelles have displayed a vital role in multidrug delivery for cancer therapy.

RESULTS AND DISCUSSION

The aim of the present review is to provide an overview on the status of micellar nanoformulations for anticancer agents, including their pre-clinical and clinical researches. Emphasis is placed on presenting the newer strategies to enhance the therapeutic efficacy of anticancer drug at the target site. The type of co-polymers used and methods for the preparation of micelles are also highlighted in the paper.

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.

Antitumor potential of the protein phosphatase inhibitor, cantharidin, and selected derivatives

Cantharidin is a potent natural protein phosphatase monoterpene anhydride inhibitor secreted by several species of blister beetle, with its demethylated anhydride analogue, (S)-palasonin, occurring as a constituent of the higher plant Butea frondosa. Cantharidin shows both potent protein phosphatase inhibitory and cancer cell cytotoxic activities, but possible preclinical development of this anhydride has been limited thus far by its toxicity. Thus, several synthetic derivatives of cantharidin have been prepared, of which some compounds exhibit improved antitumor potential and may have use as lead compounds. In the present review, the potential antitumor activity, structure-activity relationships, and development of cantharidin-based anticancer drug conjugates are summarized, with protein phosphatase-related and other types of mechanisms of action discussed. Protein phosphatases play a key role in the tumor microenvironment, and thus described herein is also the potential for developing new tumor microenvironment-targeted cancer chemotherapeutic agents, based on cantharidin and its naturally occurring analogues and synthetic derivatives.

Norcantharidin: research advances in pharmaceutical activities and derivatives in recent years

Cantharidin (CTD) is the main bioactive component of Cantharides, which is called Banmao in Traditional Chinese Medicine (TCM). Norcantharidin (NCTD) is a structural modifier of CTD. To compare with CTD, NCTD has lighter side effects and stronger bioactivity in anti-cancer through inhibiting cell proliferation, causing apoptosis and autophagy, overwhelming migration and metastasis, affecting immunity as well as lymphangiogenesis. Examples of these effects include suppressing Protein Phosphatase 2A and modulating Wnt/beta catenin signal, with Caspase family proteins, AMPK pathway and c-Met/EGFR pathway involving respectively. Moreover, NCTD has the effects of immune enhancement, anti-platelet aggregation and inhibition of renal interstitial fibrosis with distinct signaling pathways. The immunological effects induced by NCTD are related to the regulation of macrophage polarization and LPS-mediated immune response. The antiplatelet activity that NCTD induced is relevant to the inhibition of platelet signaling and the downregulation of α2 integrin. Furthermore, some of novel derivatives designed and synthesized artificially show stronger biological activities (e.g., anticancer effect, enzyme inhibition effect, antioxidant effect) and lower toxicity than NCTD itself. Plenty of literatures have reported various pharmacological effects of NCTD, particularly the anticancer effect, which has been widely concerned in clinical application and laboratory research. In this review, the pharmaceutical activities and derivatives of NCTD are discussed, which can be reference for further study.

The antitumour drug ABTL0812 impairs neuroblastoma growth through endoplasmic reticulum stress-mediated autophagy and apoptosis

Neuroblastoma is the leading cause of cancer death in children aged 1 to 4 years. Particularly, five-year overall survival for high-risk neuroblastoma is below 50% with no curative options when refractory or relapsed. Most of current therapies target cell division and proliferation, thereby inducing DNA damage and programmed cell death. However, aggressive tumours often present alterations of these processes and are resistant to therapy. Therefore, exploring alternative pathways to induce tumour cell death will provide new therapeutic opportunities for these patients. In this study we aimed at testing the therapeutic potential of ABTL0812, a novel anticancer drug that induces cytotoxic autophagy to eliminate cancer cells, which is currently in phase II clinical trials of adult tumours. Here, we show that ABTL0812 impaired the viability of clinical representative neuroblastoma cell lines regardless of genetic alterations associated to bad prognosis and resistance to therapy. Oral administration of ABTL0812 to mice bearing neuroblastoma xenografts impaired tumour growth. Furthermore, our findings revealed that, in neuroblastoma, ABTL0812 induced cancer cell death via induction of endoplasmic reticulum stress, activation of the unfolded protein response, autophagy and apoptosis. Remarkably, ABTL0812 potentiated the antitumour activity of chemotherapies and differentiating agents such as irinotecan and 13-cis-retinoic acid. In conclusion, ABTL0812 distinctive mechanism of action makes it standout to be used alone or in combination in high-risk neuroblastoma patients.

Neuroblastoma patient-derived cultures are enriched for a mesenchymal gene signature and reflect individual drug response

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient‐derived cell cultures (PDCs) from chemo‐naïve and post–treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo‐response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal‐type gene expression signature and showed upregulation of pro‐angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard‐of‐care cytotoxics at human C_max‐equivalent concentrations, MYCN‐amplified and non‐MYCN‐amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients’ responses, and correlated with gene signatures of chemosensitivity. In this translational proof‐of‐concept study, early‐phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug‐response testing.

The Inhibitory Effect of Carboplatin Injection on Human Neuroblastoma SK-N-SH

The purpose of our study was to investigate the inhibitory effect of carboplatin injection on human neuroblastoma human neuroblastoma cell (SK-N-SH) cells and to clarify its action mechanism. In this study, human neuroblastoma SK-N-SH cells were divided into two groups. The treatment group was intervened by carboplatin injection (25 μM), while the control group was intervened by drug solvent. After treating separately for 24 and 72 h, the cells were collected, and western blot (WB) and real-time PCR were used to detect the expression of the proliferation marker protein (Ki67); cells grown on cover slips were prepared and immunocytochemistry (ICC) and hematoxylin-eosin (HE) staining were adopted to observe the protein expression of Ki67 and the morphological changes of the cells; clone formation assay was used to detect the clonality of each cell group. The cytotoxicity of carboplatin on SK-N-SH cell was checked by AlamarBlue viability test. Both WB and PCR results showed that after cells were injected with carboplatin for 24 and 72 h, the expression levels of both Ki67 gene and protein were decreased, and they had a significant difference from those of the control group. Carboplatin injection inhibited the expression of Ki67, and the inhibitory effect was particularly significant as the action time prolonged. ICC results showed that the protein expression of Ki67 in the treatment group was lower than that in the control group, and there was a significant difference in expression between them. As shown by HE results, the number of cell necrosis and apoptosis in the treatment group was significantly higher than that in the control group, while the results of clone formation assay showed that in the treatment group, after being injected with carboplatin, the proliferation ability of cells was inhibited, so the number of cells was significantly reduced compared with that of the control group. Carboplatin at the tested concentration displayed no cytotoxicity on SK-N-SH cell. The conclusions are that carboplatin injection can inhibit human neuroblastoma SK-N-SH cells, and the longer it acts on SK-N-SH cells, the more obvious the inhibitory effect would be.

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.

Organoseleno cytostatic derivatives: Autophagic cell death with AMPK and JNK activation

Selenocyanates and diselenides are potential antitumor agents. Here we report two series of selenium derivatives related to selenocyanates and diselenides containing carboxylic, amide and imide moieties. These compounds were screened for their potency and selectivity against seven tumor cell lines and two non-malignant cell lines. Results showed that MCF-7 cells were especially sensitive to the treatment, with seven compounds presenting GI₅₀ values below 10 μM. Notably, the carboxylic selenocyanate 8b and the cyclic imide 10a also displayed high selectivity for tumor cells. Treatment of MCF-7 cells with these compounds resulted in cell cycle arrest at S phase, increased levels of pJNK and pAMPK and caspase independent cell death. Autophagy inhibitors wortmannin and chloroquine partially prevented 8b and 10a induced cell death. Consistent with autophagy, increased Beclin1 and LC3-IIB and reduced SQSTM1/p62 levels were detected. Our results point to 8b and 10a as autophagic cell death inducers.

Promising positive liver targeting delivery system based on arabinogalactan-anchored polymeric micelles of norcantharidin

Liver cancer is the third most common cause of global cancer-related deaths. This study focused on newly developed drug delivery systems with hepatocyte asialoglycoprotein receptor binding targeting the liver. Although norcantharidin (NCTD) is effective in primary liver cancer treatment, its toxicity in the urinary system remains. Positive liver-targeting effect could be achieved by preparing polymer micelles by arabinogalactan on the surface of N-(4-methylimidazole)-hydroxyethyl-chitosan (MHC). HepG2 cells were used to analyze the cytotoxicity, invasion, apoptosis and uptake of NCTD-loaded micelles. The in vivo antitumor efficacy of NCTD-M was evaluated using tumor-bearing nude mice. Successful preparation of NCTD-M was shown. In vivo imaging showed that micelles significantly increased positive liver drug targeting. Laser confocal microscopy showed increased cellular uptake of micelles. NCTD-M also enhanced cell invasion and the proportion of apoptotic cells. Compared with the other groups, the micelles showed better antitumor effects in vivo. Therefore, the positive liver-targeting NCTD-M, which can enhance antitumor efficacy and reduce toxicity, could be a promising and effective therapeutic agent for liver cancer treatment.

Norcantharidin inhibits viability and induces cell cycle arrest and apoptosis in osteosarcoma

Osteosarcoma is the most frequent malignant bone tumor in children and adolescents. Norcantharidin (NCTD) is a purified component from blister beetles and has been identified to exert antitumor effects in a variety of cancer types. However, the antitumor effect of NCTD in osteosarcoma remains to be elucidated. In the current study, it was first demonstrated that NCTD inhibited proliferation and induced G2/M-phase arrest and cell apoptosis in human osteosarcoma cells. Furthermore, NCTD significantly decreased the phosphorylation of Akt and the mammalian target of rapamycin in human osteosarcoma cells. These results suggest that NCTD is a promising candidate for the treatment of osteosarcoma patients in the future.