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

The roles of cancer stem cell-derived secretory factors in shaping the immunosuppressive tumor microenvironment in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide and has a poor prognosis. Although immune checkpoint inhibitors have entered a new era of HCC treatment, their response rates are modest, which can be attributed to the immunosuppressive tumor microenvironment within HCC tumors. Accumulating evidence has shown that tumor growth is fueled by cancer stem cells (CSCs), which contribute to therapeutic resistance to the above treatments. Given that CSCs can regulate cellular and physical factors within the tumor niche by secreting various soluble factors in a paracrine manner, there have been increasing efforts toward understanding the roles of CSC-derived secretory factors in creating an immunosuppressive tumor microenvironment. In this review, we provide an update on how these secretory factors, including growth factors, cytokines, chemokines, and exosomes, contribute to the immunosuppressive TME, which leads to immune resistance. In addition, we present current therapeutic strategies targeting CSC-derived secretory factors and describe future perspectives. In summary, a better understanding of CSC biology in the TME provides a rational therapeutic basis for combination therapy with ICIs for effective HCC treatment.

Protein arginine methyltransferases (PRMTs): Orchestrators of cancer pathogenesis, immunotherapy dynamics, and drug resistance

Protein Arginine Methyltransferases (PRMTs) are a family of enzymes regulating protein arginine methylation, which is a post-translational modification crucial for various cellular processes. Recent studies have highlighted the mechanistic role of PRMTs in cancer pathogenesis, immunotherapy, and drug resistance. PRMTs are involved in diverse oncogenic processes, including cell proliferation, apoptosis, and metastasis. They exert their effects by methylation of histones, transcription factors, and other regulatory proteins, resulting in altered gene expression patterns. PRMT-mediated histone methylation can lead to aberrant chromatin remodeling and epigenetic changes that drive oncogenesis. Additionally, PRMTs can directly interact with key signaling pathways involved in cancer progression, such as the PI3K/Akt and MAPK pathways, thereby modulating cell survival and proliferation. In the context of cancer immunotherapy, PRMTs have emerged as critical regulators of immune responses. They modulate immune checkpoint molecules, including programmed cell death protein 1 (PD-1), through arginine methylation. Drug resistance is a significant challenge in cancer treatment, and PRMTs have been implicated in this phenomenon. PRMTs can contribute to drug resistance through multiple mechanisms, including the epigenetic regulation of drug efflux pumps, altered DNA damage repair, and modulation of cell survival pathways. In conclusion, PRMTs play critical roles in cancer pathogenesis, immunotherapy, and drug resistance. In this overview, we have endeavored to illuminate the mechanistic intricacies of PRMT-mediated processes. Shedding light on these aspects will offer valuable insights into the fundamental biology of cancer and establish PRMTs as promising therapeutic targets.

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.

Norcantharidin potentiates sorafenib antitumor activity in hepatocellular carcinoma rat model through inhibiting IL-6/STAT3 pathway

In hepatocellular carcinoma (HCC), sorafenib (Sora) efficacy is limited by primary and/or acquired resistance. Emerging evidence shows that the inflammatory factor interleukin 6 (IL-6) plays a role in Sora resistance. Norcantharidin (NCTD), a derivative of cantharidine, was identified as a potent IL-6 inhibitor. Thus, in this study, we evaluated NCTD ability to improve the Sora efficacy in HCC and its underlying molecular mechanisms. Male Sprague Dawely rats were administered NCTD (0.1 mg/kg/day; orally) or Sora (10 mg/kg day; orally) or combination for 6 weeks after HCC induction using thioacetamide (200 mg/kg; ip; 2 times/wk) for 16 weeks. Our results showed that NCTD greatly enhanced Sora activity against HCC and potentiated Sora-induced oxidative stress. NCTD enhanced Sora-induced tumor immunity reactivation by decreasing both fibrinogen-like protein 1 level and increasing both tumor necrosis factor-α gene expression along with CD8+ T cells number. Also, NCTD augmented Sora attenuation activity against TAA-induced angiogenesis and metastasis by decreasing VEGFA, HIF-1α, serum lactate dehydrogenase enzyme, and vimentin levels. The combined use of NCTD/Sora suppressed drug resistance and stemness by downregulating ATP-binding cassette subfamily G member 2, neurogenic locus notch homolog protein, spalt-like transcription factor 4, and CD133. NCTD boosted Sora antiproliferative and apoptotic activities by decreasing Ccnd1 and BCL2 expressions along with increasing BAX and caspase-3 expressions. To our knowledge, this study represents the first study providing evidence for the potential novel therapeutic use of NCTD/Sora combination for HCC. Moreover, no previous studies have reported the effect of NCTD on FGL1.

Harnessing function of EMT in hepatocellular carcinoma: From biological view to nanotechnological standpoint

Management of cancer metastasis has been associated with remarkable reduction in progression of cancer cells and improving survival rate of patients. Since 90% of mortality are due to cancer metastasis, its suppression can improve ability in cancer fighting. The EMT has been an underlying cause in increasing cancer migration and it is followed by mesenchymal transformation of epithelial cells. HCC is the predominant kind of liver tumor threatening life of many people around the world with poor prognosis. Increasing patient prognosis can be obtained via inhibiting tumor metastasis. HCC metastasis modulation by EMT and HCC therapy by nanoparticles are discussed here. First of all, EMT happens during progression and advanced stages of HCC and therefore, its inhibition can reduce tumor malignancy. Moreover, anti-cancer compounds including all-trans retinoic acid and plumbaging, among others, have been considered as inhibitors of EMT. The EMT association with chemoresistance has been evaluated. Moreover, ZEB1/2, TGF-β, Snail and Twist are EMT modulators in HCC and enhancing cancer invasion. Therefore, EMT mechanism and related molecular mechanisms in HCC are evaluated. The treatment of HCC has not been only emphasized on targeting molecular pathways with pharmacological compounds and since drugs have low bioavailability, their targeted delivery by nanoparticles promotes HCC elimination. Moreover, nanoparticle-mediated phototherapy impairs tumorigenesis in HCC by triggering cell death. Metastasis of HCC and even EMT mechanism can be suppressed by cargo-loaded nanoparticles.

Deciphering STAT3 signaling potential in hepatocellular carcinoma: tumorigenesis, treatment resistance, and pharmacological significance

Hepatocellular carcinoma (HCC) is considered one of the greatest challenges to human life and is the most common form of liver cancer. Treatment of HCC depends on chemotherapy, radiotherapy, surgery, and immunotherapy, all of which have their own drawbacks, and patients may develop resistance to these therapies due to the aggressive behavior of HCC cells. New and effective therapies for HCC can be developed by targeting molecular signaling pathways. The expression of signal transducer and activator of transcription 3 (STAT3) in human cancer cells changes, and during cancer progression, the expression tends to increase. After induction of STAT3 signaling by growth factors and cytokines, STAT3 is phosphorylated and translocated to the nucleus to regulate cancer progression. The concept of the current review revolves around the expression and phosphorylation status of STAT3 in HCC, and studies show that the expression of STAT3 is high during the progression of HCC. This review addresses the function of STAT3 as an oncogenic factor in HCC, as STAT3 is able to prevent apoptosis and thus promote the progression of HCC. Moreover, STAT3 regulates both survival- and death-inducing autophagy in HCC and promotes cancer metastasis by inducing the epithelial-mesenchymal transition (EMT). In addition, upregulation of STAT3 is associated with the occurrence of chemoresistance and radioresistance in HCC. Specifically, non-protein-coding transcripts regulate STAT3 signaling in HCC, and their inhibition by antitumor agents may affect tumor progression. In this review, all these topics are discussed in detail to provide further insight into the role of STAT3 in tumorigenesis, treatment resistance, and pharmacological regulation of HCC.

FOXK1 regulates epithelial-mesenchymal transition and radiation sensitivity in nasopharyngeal carcinoma via the JAK/STAT3 signaling pathway

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common head and neck tumor in China. Forkhead box (FOX) proteins have 19 subfamilies, which can maintain cell metabolism, regulate cell cycle and cell growth, etc. FOXK1 is a member of the FOX family, and studies have found that FOXK1 is closely related to tumors.

OBJECTIVE

This experiment aims to study the effects of FOXK1 interference on proliferation, apoptosis, invasion, epithelial-mesenchymal transition (EMT), and radiosensitivity, by regulating the Janus kinas/signal translator and activator of the transfer 3 (JAK/STAT3) pathway.

METHODS

The expression of FOXK1 was detected via immunohistochemistry using clinical nasopharyngeal carcinoma tissues and adjacent tissues. The relationship between FOXK1 expression and tumor stage was subsequently evaluated. The colony formation rate was calculated through the colony formation experiment. Cell apoptosis and cell cycle distribution were detected using flow cytometry, while cell invasion was detected using the Transwell method. The number of cells in the nucleus of each group after 30 min, 4 h, and 24 h of radiotherapy with the 2 Gy dose was counted using immunofluorescence under γ-H2AX focal points of a laser confocal microscope.

RESULTS

FOXK1 is clearly expressed in the patients' cancer tissues. The expression of FOXK1 was significantly correlated with the patient's sex. FOXK1 interference or Peficitinib can upregulate the apoptosis rate of 5-8 F and CNE-2 cells; increase the G2 phase of cells; and inhibit the invasion, migration, and EMT of cells. At the same time, FOXK1 interference can downregulate the protein expression of p-JAK1, p-JAK2, and p-STAT3 in cells. Interference from FOXK1 or Peficitinib alone can reduce the rate of cell colony formation under different radiation doses, and enhance the green fluorescence intensity of γ-H2AX in the nucleus after 4 and 24 h of the 2 Gy dose of radiotherapy. These results are optimal when FOXK1 interference and Peficitinib are used together.

CONCLUSION

FOXK1 interference in NPC cells can regulate EMT through the JAK/STAT3 signal pathway, enhance the radiosensitivity of cells, and thus inhibit tumor cell progression.

Potential of Compounds Originating from the Nature to Act in Hepatocellular Carcinoma Therapy by Targeting the Tumor Immunosuppressive Microenvironment: A Review

Hepatocellular carcinoma (HCC), the most prevalent subtype of liver cancer, is the second main reason for cancer-related deaths worldwide. In recent decades, sufficient evidence supported that immunotherapy was a safe and effective treatment option for HCC. However, tolerance and frequent recurrence and metastasis occurred in patients after immunotherapy due to the complicated crosstalk in the tumor immunosuppressive microenvironment (TIME) in HCC. Therefore, elucidating the TIME in HCC and finding novel modulators to target TIME for attenuating immune suppression is critical to optimize immunotherapy. Recently, studies have shown the potentially immunoregulatory activities of natural compounds, characterized by multiple targets and pathways and low toxicity. In this review, we concluded the unique role of TIME in HCC. Moreover, we summarized evidence that supports the hypothesis of natural compounds to target TIME to improve immunotherapy. Furthermore, we discussed the comprehensive mechanisms of these natural compounds in the immunotherapy of HCC. Accordingly, we present a well-grounded review of the naturally occurring compounds in cancer immunotherapy, expecting to shed new light on discovering novel anti-HCC immunomodulatory drugs from natural sources.

Norcantharidin down-regulates iron contents in the liver and spleen of lipopolysaccharide-treated mice

Objective

The inhibiting effect of Norcantharidin (NCTD) on IL-6 (interleukin-6) and STAT3 and the involvement of the IL-6/STAT3 pathway in hepcidin expression prompted us to speculate that NCTD could affect iron metabolism.

Methods

We examined the effects of NCTD on serum iron (SI) and transferrin (Tf) saturation, iron and ferritin light chain (FTL), transferrin receptor 1 (TfR1), divalent metal transporter 1 (DMT1), ferroportin 1 (Fpn1), iron regulatory protein 1 (IRP1) and hepcidin, as well as IL-6 and STAT3 in the liver, spleen and duodenum of mice treated with lipopolysaccharide (LPS) in vivo, using RT-PCR, Western blotting and immunofluorescence analysis.

Results

NCTD could increase SI and Tf saturation and reduce tissue iron and FTL content by affecting expression of cell-iron transport proteins TfR1, DMT1 and Fpn1. The impact of NCTD on TfR1, DMT1 and Fpn1 expression is mediated by up-regulating IRP1 and down-regulating hepcidin expression, while NCTD-induced down-regulation of hepcidin is mediated by the IL-6/STAT3 signalling pathway in LPS-treated mice.

Conclusions

NCTD affects iron metabolism by modifying the expression of IL-6/JAK2/STAT3/hepcidin and IRP1 and suggest that the ability of NCTD to reduce tissue iron contents may be a novel mechanism associated with the anti-cancer effects of NCTD.

Norcantharidin overcomes vemurafenib resistance in melanoma by inhibiting pentose phosphate pathway and lipogenesis via downregulating the mTOR pathway

Melanoma is the most aggressive type of skin cancer with a high incidence and low survival rate. More than half of melanomas present the activating BRAF mutations, along which V600E mutant represents 70%–90%. Vemurafenib (Vem) is an FDA-approved small-molecule kinase inhibitor that selectively targets activated BRAF V600E and inhibits its activity. However, the majority of patients treated with Vem develop acquired resistance. Hence, this study aims to explore a new treatment strategy to overcome the Vem resistance. Here, we found that a potential anticancer drug norcantharidin (NCTD) displayed a more significant proliferation inhibitory effect against Vem-resistant melanoma cells (A375R) than the parental melanoma cells (A375), which promised to be a therapeutic agent against BRAF V600E-mutated and acquired Vem-resistant melanoma. The metabolomics analysis showed that NCTD could, especially reverse the upregulation of pentose phosphate pathway and lipogenesis resulting from the Vem resistance. In addition, the transcriptomic analysis showed a dramatical downregulation in genes related to lipid metabolism and mammalian target of the rapamycin (mTOR) signaling pathway in A375R cells, but not in A375 cells, upon NCTD treatment. Moreover, NCTD upregulated butyrophilin (BTN) family genes, which played important roles in modulating T-cell response. Consistently, we found that Vem resistance led to an obvious elevation of the p-mTOR expression, which could be remarkably reduced by NCTD treatment. Taken together, NCTD may serve as a promising therapeutic option to resolve the problem of Vem resistance and to improve patient outcomes by combining with immunomodulatory therapy.

Two Zn(II) coordination polymers with anticancer drug norcantharidin as ligands for cancer chemotherapy

Here two Zn(II) coordination polymers [Zn₂₀(DMCA)₁₂]O₁₂ (DMCA = demethylcantharic acid, DMCA-Zn1) and [Zn(DMCA)](H₂O)₂ (DMCA-Zn2) are synthesized from a broad-spectrum anticancer drug norcantharidin (NCTD) and Zn(NO₃)₂·6H₂O under solvothermal conditions. By mechanical grinding with a biocompatible polymeric surfactant F127, ultrasonic treatment and filtration, DMCA-Zn1 and DMCA-Zn2 can be transformed into stable nanoparticles (DMCA-Zn1 NPs and DMCA-Zn2 NPs) suspended in water with average diameters of around 190 nm and 162 nm for drug delivery. The in vitro evaluation indicates that DMCA-Zn1 NPs and DMCA-Zn2 NPs can enter into HepG2 and Hep3B cancer cells via endocytosis and inhibit their proliferation. Meanwhile they exhibit relatively low toxicity to L927 normal cells. The in vivo evaluation confirms that DMCA-Zn1 NPs and DMCA-Zn2 NPs can more effectively inhibit the growth of Hep3B tumors with relatively few side effects compared with free NCTD. This approach can be extended to other anticancer drugs to construct nanodrug delivery systems for cancer treatment.

Downregulation of amine oxidase copper containing 1 inhibits tumor progression by suppressing IL-6/JAK/STAT3 pathway activation in hepatocellular carcinoma

Amine oxidase copper containing 1 (AOC1) is a copper-containing amine oxidase that catalyzes the deamination of polyamines. AOC1 functions as an oncogene in human gastric cancer. There is little information available regarding the function of AOC1 in hepatocellular carcinoma (HCC). In the present study, reverse transcription-quantitative PCR was used to detect the expression levels of AOC1 in HCC tissues, and the role of AOC1 in HCC progression was determined using western blot, Cell Counting Kit 8, clone formation, wound-healing and Transwell assays. An AOC1 survival curve was generated with data downloaded from The Cancer Genome Atlas, and Gene Set Enrichment Analysis was performed to investigate the potential biological mechanisms of AOC1 in HCC. AOC1 was found to be upregulated in HCC tissues, which was associated with a poor prognosis. Furthermore, AOC1-knockdown inhibited HCC cell proliferation, migration and invasiveness, suppressed IL-6 expression, as well as decreasing JAK2 and STAT3 phosphorylation. Ultimately, the results of the present study illustrate that AOC1 promoted the proliferation, migration and invasiveness of HCC cells by regulating the IL-6/JAK/STAT3 pathway.

Silencing of ISLR inhibits tumour progression and glycolysis by inactivating the IL‑6/JAK/STAT3 pathway in non‑small cell lung cancer

Lung cancer is the second most frequent cancer type in both men and women, and it is considered to be one of the major causes of cancer-related mortality worldwide. However, few biomarkers are currently available for the diagnosis of lung cancer. The aim of the present study was to investigate the function of the immunoglobulin superfamily containing leucine-rich repeat (ISLR) gene in non-small cell lung cancer (NSCLC) cells, and to elucidate the underlying molecular mechanism of its action. The current study analysed ISLR expression in NSCLC tumour and normal tissues using The Cancer Genome Atlas cohort datasets. ISLR expression in NSCLC cell lines was determined using reverse transcription-quantitative PCR. Cell Counting Kit-8, soft agar colony formation, wound healing, Transwell, flow cytometry and glycolysis assays were performed to determine the effects of ISLR silencing or overexpression on cells. The expression levels of the genes involved in epithelial-mesenchymal transition (EMT), apoptosis and glycolysis were evaluated via western blotting. Transfected cells were exposed to the pathway activator, IL-6, to validate the regulatory pathway. ISLR was overexpressed in NSCLC tissues and cell lines. Overall, patients with high ISLR expression had lower survival rates. In addition, small interfering RNA-ISLR inhibited the proliferation, EMT, migration, invasion and glycolysis of NSCLC cells, and promoted their apoptosis. ISLR overexpression had the opposite effect on tumour progression and glycolysis in NSCLC cells. Gene set enrichment analysis and western blotting results indicated that the IL-6/Janus kinase (JAK)/STAT3 pathway was enriched in ISLR-related NSCLC. Knockdown of ISLR inhibited IL-6-induced proliferation, invasion, migration and glycolysis in human NSCLC cells. In summary, ISLR silencing can inhibit tumour progression and glycolysis in NSCLC cells by activating the IL-6/JAK/STAT3 signalling pathway, which is a potential molecular target for NSCLC diagnosis and treatment.

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.

Ginsenoside Compound K Regulates HIF-1α-Mediated Glycolysis Through Bclaf1 to Inhibit the Proliferation of Human Liver Cancer Cells

This study aimed to demonstrate that ginsenoside compound K (20 (S)-ginsenoside CK; CK) downregulates Bcl-2-associated transcription factor 1 (Bclaf1), which inhibits the hypoxia-inducible factor-1α (HIF-1α)-mediated glycolysis pathway to inhibit the proliferation of liver cancer cells. Treatment of hepatoma cells (Bel-7404 and Huh7) under hypoxic conditions with different concentrations of CK showed that CK inhibited the proliferation of hepatoma cells in a time- and concentration-dependent manner; furthermore, the ability of the cells to form colonies was reduced, and cell growth was blocked in the G0/G1 phase. CK promoted the degradation of HIF-1α ubiquitination in liver cancer cells by regulating the expression of HIF-1α and related ubiquitination proteins; moreover, it reduced the activity of key enzymes involved in glycolysis, the pressure of cellular glycolysis, and the rate of real-time ATP production, thereby inhibiting the glycolysis pathway. It also decreased the expression of Bclaf1 in hypoxic liver cancer cells and thus reduced the ability of Bclaf1 to bind to HIF-1α. CK treatment of Bel-7404 and Huh7 cells with CRISPR/Cas9-engineered knock out of Bclaf1 gene under hypoxic conditions further suppressed the expression of HIF-1α, promoted HIF-1α ubiquitination, and inhibited the glycolysis pathway. In a rat model of primary liver cancer induced by diethylnitrosamine, positron emission tomography and computed tomography scans showed that after CK administration, tumor tissue volumes were reduced and glucose uptake capacity decreased. Increased Bclaf1 and HIF-1α expression promoted the ubiquitination of HIF-1α and inhibited the glycolysis pathway, thereby inhibiting the proliferation of liver cancer cells. In summary, this study confirmed by in vitro and in vivo experiments that in hypoxic liver cancer cells CK downregulates the expression of Bclaf1, inhibits the HIF-1α-mediated glycolysis pathway, and inhibits cell proliferation, suggesting that the CK-mediated effects on Bclaf1 may represent a novel therapeutic approach for the treatment of liver cancer patients.

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.

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.

Knockdown of interferon-stimulated gene 15 affects the sensitivity of hepatocellular carcinoma cells to norcantharidin

Interferon-stimulated gene 15 (ISG15) serves a crucial role in hepatocellular carcinoma (HCC) progression. The present study explored the effect of ISG15 knockdown on the sensitivity of HCC cells to norcantharidin. The expression of ISG15 in HCC tissues and cell lines was assessed by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. Pearson's χ² test was conducted to analyze the correlation between the clinicopathological features and ISG15 expression of patients with HCC. In addition, HCC cells were transfected with small interfering RNA against ISG15, ISG15 overexpression plasmid or respective negative controls. Cell proliferation, clonogenic ability and apoptosis were examined by Cell Counting Kit-8, colony formation and Annexin V/propidium iodide staining assays, respectively. Protein expression was assessed by western blot analysis. The results revealed that ISG15 was overexpressed in HCC tissues, and that ISG15 expression was positively correlated with HCC differentiation and metastasis. Downregulation of ISG15 increased the sensitivity of HCC cells to norcantharidin, and norcantharidin treatment reversed the tumor-promoting effects of ISG15 overexpression exerted in HCC cells. Furthermore, the expression levels of apoptosis-associated proteins were regulated by ISG15 and norcantharidin. Taken together, the observed increase in the sensitivity of HCC cells to norcantharidin was facilitated by ISG15 knockdown and may provide novel insights for HCC therapy.

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.

Traditional Chinese medicine combined with hepatic targeted drug delivery systems: A new strategy for the treatment of liver diseases

Liver diseases are clinically common and present a substantial public health issue. Many of the currently available drugs for the treatment of liver diseases suffer from limitations that include low hepatic distribution, lack of target effects, poor in vivo stability and adverse effects on other organs. Consequently, conventional treatment of hepatic diseases is ineffective. TCM is commonly used in the treatment of liver diseases worldwide, particularly in China, and has advantages over conventional therapy. HTDDS can be designed to enhance clinical efficacy in the treatment of liver diseases. We have conducted an extensive review of 335 studies reported since 1964. These included about 166 references involving the treatment of liver diseases with TCM (covering active components of TCM, single TCM and Chinese medicine formulas), 169 reports on HTDDS and background studies on liver-related diseases. Here we review the long history of TCM in the treatment of liver diseases.We have also reviewed the status of studies on active components of TCM using nanotechnology-based targeted delivery systems to provide support for further research and development of TCM-based targeted preparations for the treatment of liver disease.

Compound K Induces Endoplasmic Reticulum Stress and Apoptosis in Human Liver Cancer Cells by Regulating STAT3

The ginsenoside compound K (20-O-β-d-glucopyranosyl-20(S)-protopanaxadiol; CK) is an intestinal bacterial metabolite of ginseng protopanaxadiol saponin that has been reported to induce apoptosis in many cancer cells; however, the precise mechanisms of its activity in human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we demonstrated that CK inhibited the growth and colony formation of HepG2 and SMMC-7721 cells, phenotypes that were mediated by inducing apoptosis. Meanwhile, CK showed lower toxicity in normal hepatoma cells. After treating HepG2 and SMMC-7721 cells with CK, p-STAT3 levels decreased, the three branches of the unfolded protein response were activated, and levels of endoplasmic reticulum stress (ERS)-related proteins were increased. We also revealed that CK decreased the DNA-binding capacity of STAT3. Moreover, silencing STAT3 with CRISPR/Cas9 technology enhanced CK-induced ERS and apoptosis. Finally, we showed that CK inhibited the growth of liver cancer xenografts with little toxicity. Mice bearing human HCC xenografts that were treated with CK showed increased GRP78 expression and decreased p-STAT3 levels. Taken together, these data showed that CK induced ERS and apoptosis by inhibiting p-STAT3 in human liver cancer cells; thus, CK might be a potential therapeutic candidate for human HCC.

Cantharidic acid induces apoptosis through the p38 MAPK signaling pathway in human hepatocellular carcinoma

Cantharidin analogs exhibit anticancer activities, including apoptosis. However, the molecular mechanisms underlying the effects of cantharidic acid (CA), a cantharidin analog, on apoptosis in hepatocellular carcinoma (HCC) cells are unclear. Thus, in this study, we evaluated the anticancer activities of CA by investigating its ability to trigger apoptosis in SK-Hep-1 cells. Our data demonstrated that CA effectively inhibited the proliferation of SK-Hep-1 cells in a dose-dependent manner. Furthermore, CA effectively triggered cell cycle arrest and induced apoptosis, as determined by flow cytometric analysis. Western blotting revealed that CA significantly activated proapoptotic signaling including caspase-3, -8, and -9 in SK-Hep-1 cells. Moreover, treatment of SK-Hep-1 cells with CA induced the activation of ERK, p38, and c-Jun N-terminal kinase. Moreover, the inhibition of p38 by specific inhibitors abolished CA-induced cell apoptosis. In conclusion, our results indicated that CA induces apoptosis in SK-Hep-1 cells through a p38-mediated apoptotic pathway and could be a new HCC therapeutic agent.