Zerumbone, a bioactive sesquiterpene, induces G2/M cell cycle arrest and apoptosis in leukemia cells via a Fas- and mitochondria-mediated pathway

Anti-cancer potential of zerumbone in cancer and glioma: current trends and future perspectives

Plant-derived immunomodulators and antitumor factors have appealed lots of attention from natural product scientists for their efficiency and safety and their important contribution to well-designed targeted drug action and delivery mechanisms. Zerumbone (ZER), the chief component of Zingiber zerumbet rhizomes, has been examined for its wide-spectrum in the treatment of multi-targeted diseases. The rhizomes have been used as food flavoring agents in numerous cuisines and in flora medication. Numerous in vivo and in vitro experiments have prepared confirmation of ZER as a potent immunomodulator as well as a potential anti-tumor agent. This review is an interesting compilation of all the important results of the research carried out to date to investigate the immunomodulatory and anticancer properties of ZER. The ultimate goal of this comprehensive review is to supply updated information and a crucial evaluation on ZER, including its chemistry and immunomodulating and antitumour properties, which may be of principal importance to supply a novel pathway for subsequent investigation to discover new agents to treat cancers and immune-related sickness. In addition, updated information on the toxicology of ZER has been summarized to support its safety profile.

Biosynthesis of Zinc Oxide-Zerumbone (ZnO-Zer) Nanoflakes Towards Evaluating Its Antibacterial and Reactive Oxygen Species (ROS)-Dependent Cytotoxic Activity

Being the second most prevalent metal oxide, zinc oxide (ZnO) nanomaterials have been widely studied and found to exhibit promising applications in various domains of biomedicine and agriculture. Considering the enhanced bioactivities displayed by secondary metabolite (SM) derived ZnO nanomaterials, present study was undertaken to evaluate the efficacy of ZnO nanoflake (NF) derived from Zerumbone (Zer), a sesquiterpenoid from Zingiber zerumbet rhizome with diverse pharmacological properties. ZnO NF prepared by homogeneous precipitation method using ZnSO4.7H2O (0.1 M) and NaOH (0.2 M) as precursors with and without the addition of Zer (0.38 mM) were characterized by powder UV-visible spectroscopy, X-ray diffraction (XRD), FT-IR spectroscopy and Field emission scanning electron microscope (FESEM) analysis. Optical and physical properties of ZnO-Zer NF were found to match with the typical ZnO nanomaterial properties. XRD analysis revealed reduction in size (15 nm) of the green synthesized ZnO-Zer NF compared to ZnO NF (21 nm). ZnO-Zer NF displayed linear correlation between concentration and antimicrobial activity to Salmonella typhi, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Determination of cytotoxic potential of the synthesized ZnO-Zer NF in cervical cancer cells (HeLa) showed higher cytotoxicity of ZnO-Zer NF (39.32 ± 3.01%) compared to Zer alone (27.02 ± 1.22%). Present study revealing improvement in bioactivity of Zer following conjugation with ZnO NF signifies potential of NF formation in improving therapeutic application of Zer that otherwise displays low solubility limiting its bioavailability.

Anticancer bioactivity of zerumbone on pediatric rhabdomyosarcoma cells

PURPOSE

Natural products are generally regarded as safe and have been shown to mediate anticancer activities against a variety of cell types. Zerumbone is a natural cyclic sesquiterpene derived from the rhizome of Zingiber zerumbet, which has attracted extensive attention in the recent decade for anticancer activities. The present study investigates the in vitro effect of zerumbone on rhabdomyosarcoma cells.

METHODS

Two rhabdomyosarcoma cell lines (RD and RH30) were used as the model system. The growth inhibition of zerumbone was measured by MTT-assay, apoptosis via flow cytometry, gene expression by real-time PCR, the migration by transwell assay, and intracellular signaling by Western blotting.

RESULTS

Zerumbone shows anticancer effects on RD and RH30 cells in a dose-dependent manner via cell growth inhibition and induction of apoptosis. Exposure of RD and RH30 cells on zerumbone also resulted in a decrease of migration and downregulation of the hedgehog pathway.

CONCLUSIONS

Taken together, our study provided the first evidence that zerumbone imparted strong inhibitory and apoptotic effects on pediatric rhabdomyosarcoma cell lines and merit further investigation as a promising candidate for the anticancer therapy.

Zerumbone acts as a radiosensitizer in head and neck squamous cell carcinoma

Introduction. Zerumbone is a phytochemical compound of the ginger plant Zingiber zerumbet with cytotoxic effects in various cancer cell lines. To date, zerumbone has shown an antiproliferative effect in oral squamous cell carcinoma cells lines. However, the effect of combination with radiation or cisplatin in head and neck squamous cell carcinoma (HNSCC) is unclear. The aim of this study was to investigate the effect of zerumbone alone, and in combination with irradiation and cisplatin on HNSCC cell lines. Methods. The three HNSCC cell lines SCC25, Cal27 and FaDu were treated with zerumbone, radiation and/or cisplatin. Cell viability and clonogenic assays were performed. The interaction between zerumbone and radiation or cisplatin was evaluated using the combination index. Apoptosis was measured by flow cytometry and cell migration was assessed using a wound healing assay. Results. Treatment with zerumbone resulted in a dose dependent induction of cytotoxicity and apoptosis in all three cell lines. The combination with cisplatin revealed a synergistic to additive effect in Cal27. The clonogenic assay showed a significant radiosensitizing effect in all three cell lines. The wound healing assay showed a reduction of cell migration in Cal27. Conclusion. The natural compound zerumbone shows a cytotoxic and proapoptotic effect on HNSCC cell lines. Furthermore, zerumbone enhances the radiation effect in all three cell lines and thus may be a suitable candidate for combination therapy in HNSCC.

Comparison of Chemical Composition and Bioactivities of Essential Oils from Fresh and Dry Rhizomes of Zingiber zerumbet (L.) Smith

The chemical constituents and the antioxidant, antimicrobial, and cytotoxic activities of fresh rhizome essential oil (FR-EO) and dry rhizome essential oil (DR-EO) of Zingiber zerumbet (L.) Smith obtained from Southwest China were compared. Zerumbone was the predominant component in both FR-EO and DR-EO (75.0% and 41.9%, respectively). FR-EO, DR-EO, and zerumbone were all demonstrated to have significant antimicrobial capacity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Proteus vulgaris, with minimum inhibitory concentration (MIC) ranging from 31.25 to 156.25 μg/mL and minimum bactericidal concentration (MBC) ranging from 62.50 to 625.00 μg/mL. Zerumbone showed the strongest antimicrobial potential against all tested microorganisms compared with the fresh and dry rhizome essential oils. FR-EO was found to be more active than DR-EO against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Proteus vulgaris. FR-EO, DR-EO, and zerumbone all showed significant cytotoxic activity against K562, PC-3, and A549 human tumor cell lines in a time- and concentration-dependent manner. Zerumbone exhibited the strongest antiproliferative activity against all tested human tumor cell lines with an IC₅₀ of 4.21–11.09 μg/mL for 72 h incubation, as compared with the fresh and dry rhizome oils. The cytotoxic activity of FR-EO (IC₅₀: 10.48–14.51 μg/mL for 72 h) was found to be significantly higher (p < 0.05) than that of DR-EO (IC₅₀: 13.83–33.24 μg/mL for 72 h). FR-EO, DR-EO, and zerumbone exhibited selective cytotoxic activity to tumor cells, with a significantly low cytotoxicity to normal cells (MRC-5, IC₅₀: 56.98–147.29 μg/mL). However, FR-EO, DR-EO, and zerumbone all exhibited weak free-radical-scavenging activity according to DPPH and ABTS analysis. The findings highlighted in this study show that FR-EO provides appreciably higher content of the bioactive compound, zerumbone, and has higher antimicrobial and cytotoxic properties than DR-EO. Thus, fresh Z. zerumbet rhizome should be preferred in cosmetic, food, and pharmaceutical applications.

Gingers and Their Purified Components as Cancer Chemopreventative Agents

Chemoprevention by ingested substituents is the process through which nutraceuticals and/or their bioactive components antagonize carcinogenesis. Carcinogenesis is the course of action whereby a normal cell is transformed into a neoplastic cell. This latter action involves several steps, starting with initiation and followed by promotion and progression. Driving these stages is continued oxidative stress and inflammation, which in turn, causes a myriad of aberrant gene expressions and mutations within the transforming cell population and abnormal gene expressions by the cells within the surrounding lesion. Chemoprevention of cancer with bioreactive foods or their extracted/purified components occurs primarily via normalizing these inappropriate gene activities. Various foods/agents have been shown to affect different gene expressions. In this review, we discuss how the chemoprevention activities of gingers antagonize cancer development.

Potential of Zerumbone as an Anti-Cancer Agent

Cancer is still a major risk factor to public health globally, causing approximately 9.8 million deaths worldwide in 2018. Despite advances in conventional treatment modalities for cancer treatment, there are still few effective therapies available due to the lack of selectivity, adverse side effects, non-specific toxicities, and tumour recurrence. Therefore, there is an immediate need for essential alternative therapeutics, which can prove to be beneficial and safe against cancer. Various phytochemicals from natural sources have been found to exhibit beneficial medicinal properties against various human diseases. Zerumbone is one such compound isolated from Zingiber zerumbet Smith that possesses diverse pharmacological properties including those of antioxidant, antibacterial, antipyretic, anti-inflammatory, immunomodulatory, as well as anti-neoplastic. Zerumbone has shown its anti-cancer effects by causing significant suppression of proliferation, survival, angiogenesis, invasion, and metastasis through the molecular modulation of different pathways such as NF-κB, Akt, and IL-6/JAK2/STAT3 (interleukin-6/janus kinase-2/signal transducer and activator of transcription 3) and their downstream target proteins. The current review briefly summarizes the modes of action and therapeutic potential of zerumbone against various cancers.

Zerumbone, a cyclic sesquiterpene, exerts antimitotic activity in HeLa cells through tubulin binding and exhibits synergistic activity with vinblastine and paclitaxel

Objectives

The aim of this study was to elucidate the antimitotic mechanism of zerumbone and to investigate its effect on the HeLa cells in combination with other mitotic blockers.

Materials and methods

HeLa cells and fluorescence microscopy were used to analyse the effect of zerumbone on cancer cell lines. Cellular internalization of zerumbone was investigated using FITC‐labelled zerumbone. The interaction of zerumbone with tubulin was characterized using fluorescence spectroscopy. The Chou and Talalay equation was used to calculate the combination index.

Results

Zerumbone selectively inhibited the proliferation of HeLa cells with an IC₅₀ of 14.2 ± 0.5 μmol/L through enhanced cellular uptake compared to the normal cell line L929. It induced a strong mitotic block with cells exhibiting bipolar spindles at the IC₅₀ and monopolar spindles at 30 μmol/L. Docking analysis indicated that tubulin is the principal target of zerumbone. In vitro studies indicated that it bound to goat brain tubulin with a Kd of 4 μmol/L and disrupted the assembly of tubulin into microtubules. Zerumbone and colchicine had partially overlapping binding site on tubulin. Zerumbone synergistically enhanced the anti‐proliferative activity of vinblastine and paclitaxel through augmented mitotic block.

Conclusion

Our data suggest that disruption of microtubule assembly dynamics is one of the mechanisms of the anti‐cancer activity of zerumbone and it can be used in combination therapy targeting cell division.

Effects of zerumbone on proliferation and apoptosis of esophageal cancer cells and on P53 and Bcl-2 expression levels

The effects of zerumbone on the proliferation and apoptosis of esophagus cancer cells and on the P53 and Bcl-2 expression levels were studied. The esophagus cancer EC-109 cells were cultured and inoculated. The effect of zerumbone on proliferation of EC-109 cells was detected via the Cell Counting Kit-8 (CCK-8) method. Cell apoptosis was detected via TdT-mediated dUTP nick end-labeling (TUNEL) staining. Moreover, the mRNA expression levels of P53 and Bcl-2 were detected via reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression levels of P53 and Bcl-2 were evaluated via western blotting. CCK-8 detection results showed that compared with control group, zerumbone in different concentrations could inhibit the activity of EC-109, and the proliferation inhibition rate was significantly increased in a concentration-dependent manner with the increase of concentration. TUNEL staining showed that cell apoptosis gradually occurred in administration group, and the number of apoptotic cells was increased in a concentration-dependent manner with the increase of concentration. RT-PCR detection results showed that the mRNA expression level of P53 in administration group was significantly increased compared with that in control group, but that of Bcl-2 was significantly decreased. Western blotting showed that the protein expression level of Bcl-2 in administration group in different concentrations was significantly increased with the increase of zerumbone concentration, but that of Bcl-2 was significantly decreased in a concentration-dependent manner. Zerumbone can inhibit the proliferation and induce apoptosis of esophageal cancer EC-109 cells, and its induction of apoptosis may be realized through upregulating the mRNA expression of P53 and downregulating the mRNA expression of Bcl-2, and upregulating the protein expression of P53 and downregulating the protein expression of Bcl-2.

Hepatoprotective Effects of Zerumbone against Paracetamol-Induced Acute Hepatotoxicity in Rats

Background

Zerumbone (ZER) is a major bioactive compound of Zingiber zerumbet, a wild ginger plant that has been documented to have anti-proliferative, anti-inflammatory and anti-oxidant properties. To investigate its hepatoprotective potential, this study was designed to determine the treatment effects of ZER on acute hepatotoxicity induced by paracetamol (PCM) in rats.

Methods

The control group was administered with phosphate buffer solution (PBS) while the other two groups received PCM alone (1000 mg/kg) and PCM + 25 mg/kg ZER, respectively, at 0 h and 4 h after PCM injection. After 24 h, the blood and liver were collected for differential white blood cell count, liver histological observation and biochemical analysis including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total protein concentration in serum and liver.

Results

Treatment with ZER was found to significantly reduce ALT (P = 0.041), AST (P = 0.044) and total hepatic protein (P = 0.045) in comparison to PCM-induced rats. Rats treated with ZER exhibited the normal structure of hepatocytes with no vacuolisation or necrosis and showed significantly reduced neutrophil count (P = 0.037). This finding suggests its ability to suppress the inflammatory processes caused by PCM overdosage and decrease the hepatocytes tendency to go through necrotic processes.

Conclusion

ZER possessed protective activity against PCM-induced acute hepatotoxicity in a rat model.

Zerumbone ameliorates high-fat diet-induced adiposity by restoring AMPK-regulated lipogenesis and microRNA-146b/SIRT1-mediated adipogenesis

Obesity is characterized by increased fat mass, as adipose tissue serves as a storage site for excess energy from food consumption. In obesity, altered lipid metabolism of adipose tissue, characterized by fatty acid uptake, de novo lipogenesis, and lipolysis, are induced. In this study, we examined the effect of zerumbone, a major sesquiterpene from wild ginger, on high-fat diet (HF)-induced obesity and dysregulated lipid metabolism in the white adipose tissues (WAT) of C57BL/6N mice. Dietary supplementation with zerumbone ameliorated HF-induced obesity and improved impaired lipid metabolism in WAT. Zerumbone additionally induced AMPK activation and phosphorylation of acetyl-CoA carboxylase, and effectively decreased adipogenic differentiation, in a concentration-dependent manner in the 3T3-L1 cells. Dysregulated microRNAs in obese WAT and adipocytes were examined, and zerumbone treatment was found to effectively reverse the robust upregulation of microRNA-146b. An increase in the levels of SIRT1, the direct target of microRNA-146b, was observed in zerumbone-treated differentiated adipocytes. This increase was additionally observed in WAT of zerumbone-supplemented mice. The antiadipogenic effect of zerumbone was found to be abolished in SIRT1-silenced 3T3-L1 cells. The increase in SIRT1 levels induced by zerumbone led to deacetylation of FOXO1 and PGC1α in WAT and differentiated 3T3-L1 cells. These findings indicate that zerumbone ameliorated diet-induced obesity and inhibited adipogenesis, and that the underlying mechanisms involved AMPK and the microRNA-146b/SIRT1 pathway. Zerumbone may represent a potential therapeutic candidate for the prevention and treatment of metabolic diseases, particularly obesity.

Zerumbone, a Cyclic Sesquiterpene from Zingiber zerumbet Induces Apoptosis, Cell Cycle Arrest, and Antimigratory Effects in SW480 Colorectal Cancer Cells

Zerumbone isolated from the rhizomes of Zingiber zerumbet was investigated for the mechanisms by which it exhibits antiproliferative activity in colorectal cancer cells (SW480). The results indicated that the zerumbone suppressed cell growth and enhanced cell apoptosis. Exposure to zerumbone induced generation of reactive oxygen species, reduced the cellular antioxidant status, decreased mitochondrial membrane potential, and activated caspase 3, caspase 8, and caspase 9 (p < 0.001). It was also found that there was a decrease in the expression of Bcl 2 and elevation of Bax (p < 0.001) on exposure to zerumbone. Furthermore, treatment with 50, 75, and 100 μM zerumbone resulted in cell cycle arrest at the G2/M phase with a value of 17.2 ± 0.1, 19.63 ± 0.25, and 26.66 ± 0.25, respectively, and also distorted the microfilament network and effectively inhibited cellular migration.

Zerumbone targets the CXCR4-RhoA and PI3K-mTOR signaling axis to reduce motility and proliferation of oral cancer cells

BACKGROUND

The CXCR4-RhoA and PI3K-mTOR signaling pathways play crucial roles in the dissemination and tumorigenesis of oral squamous cell carcinoma (OSCC). Activation of these pathways have made them promising molecular targets in the treatment of OSCC. Zerumbone, a bioactive monocyclic sesquiterpene isolated from the rhizomes of tropical ginger, Zingiber zerumbet (L.) Roscoe ex Sm. has displayed promising anticancer properties with the ability to modulate multiple molecular targets involved in carcinogenesis. While the anticancer activities of zerumbone have been well explored across different types of cancer, the molecular mechanism of action of zerumbone in OSCC remains largely unknown.

PURPOSE

Here, we investigated whether OSCC cells were sensitive towards zerumbone treatment and further determined the molecular pathways involved in the mechanism of action.

METHODS

Cytotoxicity, anti-proliferative, anti-migratory and anti-invasive effects of zerumbone were tested on a panel of OSCC cell lines. The mechanism of action of zerumbone was investigated by analysing the effects on the CXCR4-RhoA and PI3K-mTOR pathways by western blotting.

RESULTS

Our panel of OSCC cells was broadly sensitive towards zerumbone with IC₅₀ values of less than 5 µM whereas normal keratinocyte cells were less responsive with IC₅₀ values of more than 25 µM. Representative OSCC cells revealed that zerumbone inhibited OSCC proliferation and induced cell cycle arrest and apoptosis. In addition, zerumbone treatment inhibited migration and invasion of OSCC cells, with concurrent suppression of endogenous CXCR4 protein expression in a time and dose-dependent manner. RhoA-pull down assay showed reduction in the expression of RhoA-GTP, suggesting the inactivation of RhoA by zerumbone. In association with this, zerumbone also inhibited the PI3K-mTOR pathway through the inactivation of Akt and S6 proteins.

CONCLUSION

We provide evidence that zerumbone could inhibit the activation of CXCR4-RhoA and PI3K-mTOR signaling pathways leading to the reduced cell viability of OSCC cells. Our results suggest that zerumbone is a promising phytoagent for development of new therapeutics for OSCC treatment.

Blocking autophagy enhances the pro-apoptotic effect of bufalin on human gastric cancer cells through endoplasmic reticulum stress

Bufalin has been used to treat cancer for several years. However, the molecular mechanisms for its anti-tumor function are not fully understood. This work aimed to investigate the effect of bufalin on the proliferation and apoptosis of human gastric cancer (HGC) cells and the roles of endoplasmic reticulum (ER) stress and autophagy in bufalin-induced apoptosis. HGC cell lines, SGC7901 and BGC823, were treated with different concentrations of bufalin or 80 nmol/l bufalin for 1, 2, 3 and 4 days. Cell counting kit-8 (CCK-8) assay and direct cell counting method were used to detect proliferation. Cell cycle arrest and apoptosis was detected using flow cytometry. Protein levels of caspase-3, -8, Bax/Bcl-2, Beclin-1, LC3, inositol-requiring enzyme 1 (IRE1) and C/EBP homologous protein (CHOP) were determined using western blotting. Autophagy was blocked using 3-methyladenine (3MA) or Atg5 siRNA to evaluate the effect of autophagy on bufalin-induced apoptosis. The IRE1 and CHOP were knocked down using specific siRNA to determine the pathway involved in bufalin-induced autophagy. It was found that bufalin significantly suppressed proliferation of SGC7901 and BGC823 cells and induced apoptosis in a time- and dose-dependent manner. The mechanism responsible for bufalin-induced apoptosis was the formation of ER stress via the IRE1-JNK pathway. Moreover, autophagy was activated during ER stress, and blocking autophagy significantly exacerbated bufalin-induced apoptosis.

Summary: Bufalin suppressed human gastric cancer cells and induced apoptosis. The mechanism was related to ER stress formation via the IRE1-JNK pathway. Blocking autophagy exacerbated bufalin-induced apoptosis.

A Review of the Biomedical Applications of Zerumbone and the Techniques for Its Extraction from Ginger Rhizomes

Zerumbone (ZER) is a phytochemical isolated from the subtropical Zingiberaceae family and as a natural compound it has different biomedical properties such as antioxidant, anti-inflammatory anti-proliferative activity. ZER also has effects on angiogenesis and acts as an antitumor drug in the treatment of cancer, showing selective toxicity toward various cancer cell lines. Several techniques also have been established for extraction of ZER from the rhizomes of ginger. This review paper is an overview of recent research about different extraction methods and their efficiencies, in vivo and vitro investigations of ZER and also its prominent chemopreventive properties and treatment mechanisms. Most of the studies mentioned in this review paper may be useful use as a knowledge summary to explain ZER extraction and anticancer activities, which will show a way for the development of strategies in the treatment of malignancies using ZER.

Zerumbone reduced the inflammatory response of acute lung injury in endotoxin-treated mice via Akt-NFκB pathway

Zerumbone, a cyclic eleven-membered sesquiterpene, is the major component of the essential oil isolated from the wild ginger, Zingiber zerumbet. There are several beneficial pharmacological activities of zerumbone including anti-inflammatory, antioxidant, and anticancer activities. Acute lung injury (ALI) is an acute pulmonary inflammatory disorder with high morbidity and mortality rate. In present study, we aimed to investigate the protective effects and mechanisms of zerumbone on endotoxin, lipopolysaccharide (LPS)-induced ALI. Mice were pretreated with zerumbone at various concentrations for 30 min followed by intratracheal administration of LPS for 6 h. Pretreatment with zerumbone not only reduced leukocytes infiltration into the alveolar space but also inhibited lung edema in LPS-induced ALI. Decreased secretion of proinflammatory cytokines such as TNFα and IL-6 caused by LPS were reversed by zerumbone. LPS-induced expressions of proinflammatory mediators, iNOS and COX-2, were inhibited by zerumbone. In addition, NFκB activation and Akt phosphorylation were inhibited by zerumbone in LPS-induced ALI. All these results suggested that the protective mechanisms of zerumbone on endotoxin-induced ALI were via inhibition of Akt-NFκB activation.

Emerging Anti-Mitotic Activities and Other Bioactivities of Sesquiterpene Compounds upon Human Cells

We review the bio-activities of natural product sesquiterpenes and present the first description of their effects upon mitosis. This type of biological effect upon cells is unexpected because sesquiterpenes are believed to inactivate proteins through Michael-type additions that cause non-specific cytotoxicity. Yet, certain types of sesquiterpenes can arrest cells in mitosis as measured by cell biology, biochemical and imaging techniques. We have listed the sesquiterpenes that arrest cells in mitosis and analyzed the biological data that support those observations. In view of the biochemical complexity of mitosis, we propose that a subset of sesquiterpenes have a unique chemical structure that can target a precise protein(s) required for mitosis. Since the process of mitotic arrest precedes that of cell death, it is possible that some sesquiterpenes that are currently classified as cytotoxic might also induce a mitotic arrest. Our analysis provides a new perspective of sesquiterpene chemical biology.

Zerumbone inhibits melanoma cell proliferation and migration by altering mitochondrial functions

It has been reported that zerumbone (ZER) has marked effects on the regulation of cell proliferation and migration in multiple types of cancer, and has anti-cancer effects on various types of malignant cell. However, the effects and underlying molecular mechanisms of treatment with ZER on melanoma cells remain unclear. In the present study, the effect of treatment with ZER on the proliferation, migration and mitochondrial function of the human melanoma cell line CHL-1 was investigated. The results of the present study indicated that treatment with ZER significantly inhibited CHL-1 cell proliferation (P<0.001). Cell migration analysis further demonstrated that ZER inhibited the migration of CHL-1 cells (P<0.001). Treatment with ZER significantly increased cellular reactive oxygen species levels (P<0.001), reduced matrix membrane potential (P<0.001), decreased ATP (P<0.001) and mitochondrial DNA (P<0.001) levels, and decreased mitochondrial transcription factor A mRNA levels (P=0.002). The results of the present study suggested that the inhibition of proliferation and migration was mediated by altered mitochondrial function. In conclusion, the results of the present study suggested that ZER has chemotherapeutic effects on human melanoma cells by altering mitochondrial function.

Exploring the immunomodulatory and anticancer properties of zerumbone

Plant-derived immunomodulators and anti-cancer agents have attracted a lot of interest from natural product scientists for their efficacy and safety, and their significant contribution towards understanding targeted drug action and drug delivery mechanisms.

Zerumbone suppresses the motility and tumorigenecity of triple negative breast cancer cells via the inhibition of TGF-β1 signaling pathway

Aberrant transforming growth factor-β (TGF-β) plays an important role in the development of cancer such as tumor metastasis and invasion. TGF-β-responsive gene signature is highly activated in chemotherapy-treated triple negative breast cancer (TNBC). Here, we investigated the effect of zerumbone (ZER) on TGF-β1 signaling pathway and tumorigenecity of TNBC cells. Our results showed that the level of TGF-β1 mRNA expression and cell invasiveness were higher in TNBC cells than in non-TNBC cells. On the other hand, the cell motility of TNBC cells was completely suppressed by LY2109761, a novel selective TGF-β receptor type I/II (TβRI/II) dual inhibitor. In addition, FN and MMP-2 expression, which play an important role on cell motility in various cancer cells, were dose-dependently decreased by LY2109761. TGF-β1 increased FN, MMP-2 and MMP-9 expression in HCC1806 TNBC cells. TGF-β1-induced MMP-9 expression was decreased by both a MEK inhibitor, UO126, and a smad3 inhibitor, SIS3. Induction of FN and MMP-2 by TGF-β1 was just decreased by SIS3. Overexpression of smad3 significantly increased FN, MMP-2, and MMP-9 expression. Interestingly, ZER significantly suppressed TGF-β1-induced FN, MMP-2, and MMP-9 expression in HCC1806 cells. In addition, ZER completely decreased TGF-β1-induced the phosphorylation of smad3. Finally, we observed that ZER suppressed the tumorigenecity such as tumor volume, weight, Ki67 expression, and metastasis in TNBC cells xenograft models. Taken together, we demonstrated that ZER suppresses TGF-β1-induced FN, MMP-2, and MMP-9 expression through the inactivation of smad3 and inhibits the tumorigenecity of TNBC cells. Therefore, we suggest that ZER may act as a promising drug for treatment of TNBC.

Galiellalactone induces cell cycle arrest and apoptosis through the ATM/ATR pathway in prostate cancer cells

Galiellalactone (GL) is a fungal metabolite that presents antitumor activities on prostate cancer in vitro and in vivo. In this study we show that GL induced cell cycle arrest in G₂/M phase, caspase-dependent apoptosis and also affected the microtubule organization and migration ability in DU145 cells. GL did not induce double strand DNA break but activated the ATR and ATM-mediated DNA damage response (DDR) inducing CHK1, H2AX phosphorylation (fH2AX) and CDC25C downregulation. Inhibition of the ATM/ATR activation with caffeine reverted GL-induced G₂/M cell cycle arrest, apoptosis and DNA damage measured by fH2AX. In contrast, UCN-01, a CHK1 inhibitor, prevented GL-induced cell cycle arrest but enhanced apoptosis in DU145 cells. Furthermore, we found that GL did not increase the levels of intracellular ROS, but the antioxidant N-acetylcysteine (NAC) completely prevented the effects of GL on fH2AX, G₂/M cell cycle arrest and apoptosis. In contrast to NAC, other antioxidants such as ambroxol and EGCG did not interfere with the activity of GL on cell cycle. GL significantly suppressed DU145 xenograft growth in vivo and induced the expression of fH2AX in the tumors. These findings identify for the first time that GL activates DDR in prostate cancer.

Chemotherapeutic effect of Zerumbone on melanoma cells through mitochondria-mediated pathways

BACKGROUND

Zerumbone (ZER) is a phytochemical that appears to regulate cell proliferation and apoptosis. It has been reported to have an anti-tumour effect in various malignant cells; however, the effect and the mechanism of ZER on melanoma cells needs to be clarified.

AIM

To explore whether ZER has an effect on human melanoma cells and to identify the mechanisms involved.

METHODS

We determined the chemotherapeutic action of ZER on the human malignant melanoma (MM) A375 cell line by CCK-8 immunohistochemistry, Hoechst 33342 staining and flow cytometry analysis. We also investigated the signalling pathways by which ZER induces apoptosis in A375 cells, using western blotting, reverse transcription PCR and caspase-3 activity analysis.

RESULTS

ZER induced significant cytotoxic action in A375 cells. Hoechst 33342 staining and flow cytometry apoptosis analysis further demonstrated that ZER induced apoptosis in A375 cells. Treatment with ZER downregulated Bcl-2 gene and protein levels, upregulated Bax and Cytochrome c gene and protein levels, and activated Caspase-3.

CONCLUSIONS

ZER might have a chemotherapeutic effect on human melanoma cells through mitochondria-mediated pathways.

Elevated IL-1β expression induces invasiveness of triple negative breast cancer cells and is suppressed by zerumbone

Aberrant interleukin-1 beta (IL-1β) expression is associated with cancer development, metastasis, and poor prognosis. Here, we have investigated the regulatory mechanism of IL-1β expression, and the inhibitory effect of zerumbone (ZER) on IL-1β expression and IL-1β-induced signatures, including cell invasion and signaling activation in triple negative breast cancer (TNBC) cells. The basal IL-1β and cell invasiveness levels were significantly higher in TNBC cells, compared with non-TNBC cells. The invasiveness of TNBC cells was also increased following IL-1β treatment. In contrast, the invasiveness of TNBC cells was decreased following IL-1 receptor antagonist (IL-1RA) treatment. Additionally, the basal IL-1β level and the invasiveness of TNBC cells were decreased by Bay11-7085. In contrast, overexpression of NF-κB (p65) caused an increase in IL-1β expression in TNBC cells. Our results showed that treatment with ZER decreased the basal IL-1β expression level, and the phosphorylation level of NF-κB, in TNBC cells. Furthermore, we found that ZER completely suppressed IL-1β-induced NF-κB phosphorylation, but did not suppress IL-1β-induced Akt phosphorylation, in TNBC cells. Our results also demonstrate that IL-1β-induced cell invasion is suppressed by ZER in TNBC cells. Taken together, we demonstrated that IL-1β expression is regulated by the NF-κB-dependent pathway, and that elevated IL-1β is directly influencing the invasiveness of TNBC cells. ZER down-regulates IL-1β expression through the inhibition of NF-κB activity, and then suppresses cell invasiveness of TNBC.

Zerumbone induces gastric cancer cells apoptosis: Involving cyclophilin A

Gastric cancer is one of the leading causes for cancer death. There is an urgent need to develop new therapeutic approaches targeting metastatic gastric cancer. It has been reported that zerumbone has the anti-cancer effects in various malignant cells. However, the effect and the mechanism of zerumbone on melanoma cells is still largely unknown. In the study, we determined the actions of zerumbone on the human gastric cancer cell line SGC-7901.We also observed the mechanism by which zerumbone induced gastric cancer cell apoptosis. Our data indicated that zerumbone significantly inhibited the growth of human gastric cancer cells in a dose-dependent manner and apoptosis was the main cause of decreased cell viability in zerumbone -treated cells. The treatment with zerumbone downregulated Cyp A and Bcl-2 levels, upregulated Bax levels, and caused Cytochrome c (Cyt-C) to release, activating Caspase-3. In summary, our study suggests that zerumbone mightinduced human gastric cancer cells apoptosis through down-regulating Cyp A and mitochondria-mediated pathways.

Zerumbone, a Sesquiterpene, Controls Proliferation and Induces Cell Cycle Arrest in Human Laryngeal Carcinoma Cell Line Hep-2

Zerumbone (ZER), a sesquiterpene found in Zingiber zerumbet Smith, has been shown to possess antiproliferative, anticancer, antioxidant, and anti-inflammatory activity against various types of human carcinoma. The molecular mechanism by which ZER mediates its activity against many cancer types is revealed by many studies. Upregulation of proapoptotic molecules and suppression of antiapoptotic gene expression are few of the mechanisms by which ZER mediates its effect. The present study is focused on investigating the effect of ZER on proliferation of laryngeal carcinoma cells (Hep-2). MTT assay results showed that ZER (0.01-100 μM) induced death of Hep-2 cells in a concentration-dependent manner; significant suppression of proliferation of Hep-2 cells was seen with a IC50 value of 15 µM. ZER at a concentration of 15 and 30 μM for 48 h showed early signs of apoptosis as evidenced by confocal microscopy imaging. Flow cytometry studies showed that ZER induced cell cycle arrest. ZER arrested Hep-2 proliferation at S and G2/M phases of cell cycle. In conclusion, these results indicate that ZER has antiproliferative effect and arrests cell cycle in Hep-2 cells in vitro. This could be a potential anticancer drug against laryngeal carcinoma.

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Zerumbone, a ginger sesquiterpene, induces apoptosis and autophagy in human hormone-refractory prostate cancers through tubulin binding and crosstalk between endoplasmic reticulum stress and mitochondrial insult

Zerumbone, a natural monocyclic sesquiterpene, is the main component of the tropical plant Zingiber zerumbet Smith. Zerumbone induced antiproliferative and apoptotic effects against PC-3 and DU-145, two human hormone-refractory prostate cancer (HRPC) cell lines. Zerumbone inhibited microtubule assembly and induced an increase of MPM-2 expression (specific recognition of mitotic proteins). It also caused an increase of phosphorylation of Bcl-2 and Bcl-xL, two key events in tubulin-binding effect, indicating tubulin-binding capability and mitotic arrest to zerumbone action. Furthermore, zerumbone induced several cellular effects distinct from tubulin-binding properties. First, zerumbone significantly increased, while paclitaxel (as a tubulin-binding control) decreased, Mcl-1 protein expression. Second, paclitaxel but not zerumbone induced Cdk1 activity. Third, zerumbone other than paclitaxel induced Cdc25C downregulation. The data suggest that, in addition to targeting tubulin/microtubule, zerumbone may act on other targets for signaling transduction. Zerumbone induced mitochondrial damage and endoplasmic reticulum (ER) stress as evidenced by the loss of mitochondrial membrane potential and upregulation of GRP-78 and CHOP/GADD153 expression. Zerumbone induced an increase of intracellular Ca(2+) levels, a crosstalk marker between ER stress and mitochondrial insult, associated with the formation of active calpain I fragment. It induced apoptosis through a caspase-dependent way and caused autophagy as evidenced by dramatic LC3-II formation. In summary, the data suggest that zerumbone is a multiple targeting compound that inhibits tubulin assembly and induces a crosstalk between ER stress and mitochondrial insult, leading to apoptosis and autophagy in HRPCs.

Antileukemic effect of zerumbone-loaded nanostructured lipid carrier in WEHI-3B cell-induced murine leukemia model

Cancer nanotherapy is progressing rapidly with the introduction of many innovative drug delivery systems to replace conventional therapy. Although the antitumor activity of zerumbone (ZER) has been reported, there has been no information available on the effect of ZER-loaded nanostructured lipid carrier (NLC) (ZER-NLC) on murine leukemia cells. In this study, the in vitro and in vivo effects of ZER-NLC on murine leukemia induced with WEHI-3B cells were investigated. The results from 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, Hoechst 33342, Annexin V, cell cycle, and caspase activity assays showed that the growth of leukemia cells in vitro was inhibited by ZER-NLC. In addition, outcomes of histopathology, transmission electron microscopy, and Tdt-mediated dUTP nick-end labeling analyses revealed that the number of leukemia cells in the spleen of BALB/c leukemia mice significantly decreased after 4 weeks of oral treatment with various doses of ZER-NLC. Western blotting and reverse-transcription quantitative polymerase chain reaction assays confirmed the antileukemia effects of ZER-NLC. In conclusion, ZER-NLC was shown to induce a mitochondrial-dependent apoptotic pathway in murine leukemia. Loading of ZER in NLC did not compromise the anticancer effect of the compound, suggesting ZER-NLC as a promising and effective delivery system for treatment of cancers.

Zerumbone increases oxidative stress in a thiol-dependent ROS-independent manner to increase DNA damage and sensitize colorectal cancer cells to radiation

Locally advanced rectal cancers are treated with neoadjuvant chemoradiation therapy followed by surgery. In a minority (~20%) of patients, no tumor is present at the time of surgery; these patients with a complete pathologic response (pathCR) to neoadjuvant therapy have better treatment outcomes. Unfortunately, the inherent radioresistance of colorectal cancer (CRC) cells dictates that the majority of patients do not achieve a pathCR. Efforts to improve these odds have fueled the search for novel, relatively less-toxic radiosensitizers with distinct molecular mechanism(s) and broad-spectrum anticancer activities. Here, we use zerumbone, a sesquiterpene from the edible ginger (Zingiber zerumbet Smith), to enhance radiosensitivity of CRC cells. Short exposure to zerumbone (7 h) profoundly sensitized CRC cells, independent of their p53 or k-RAS status. Zerumbone enhanced radiation-induced cell cycle arrest (G2/M), increased radiation-induced apoptosis, but induced little apoptosis by itself. Zerumbone significantly enhanced radiation-induced DNA damage, as evident by delayed resolution of post-irradiation nuclear γH2AX foci, whereas zerumbone treatment alone did not induce γH2AX foci formation. Zerumbone pretreatment inhibited radiation-induced nuclear expression of DNA repair proteins ataxia-telangiectasia mutated (ATM) and DNA-PKcs. Interestingly, zerumbone-mediated radiosensitization did not involve reactive oxygen species (ROS), but was mediated through depletion of cellular glutathione (GSH). Ability of only thiol-based antioxidants to abrogate zerumbone-mediated radiosensitization further corroborated this hypothesis. The α,β-unsaturated carbonyl group in zerumbone was found to be essential for its bioactivity as zerumbone analog α-Humulene that lacks this functional group, could neither radiosensitize CRC cells, nor deplete cellular GSH. Our studies elucidate novel mechanism(s) of zerumbone's ability to enhance CRC radiosensitivity.

Zerumbone suppresses EGF-induced CD44 expression through the inhibition of STAT3 in breast cancer cells

Expression of the CD44 gene is upregulated in breast cancer cells and is correlated with patient survival. Aberrant CD44 expression promotes tumor progression and metastasis. In the present study, we investigated the role of zerumbone (ZER) on regulatory mechanisms of CD44 expression in breast cancer cells. Our results showed that CD44 expression was significantly increased by epidermal growth factor receptor (EGFR) ligands in SKBR3 breast cancer cells. In contrast, EGF-induced CD44 expression was decreased by a MEK1/2 inhibitor, UO126, or STAT3 inhibitor, STAT3 VI, respectively. Notably, ZER downregulated the basal level of CD44 expression in CD44+ breast cancer cells. In addition, the induction of CD44 expression by EGFR ligands, EGF or TGF-α, was markedly decreased by ZER treatment. Finally, we investigated the inhibitory mechanism of ZER on EGF-induced CD44 expression. Our results showed that EGF-induced phosphorylation of STAT3 was completely suppressed by ZER. Collectively, ZER suppressed EGF-induced CD44 expression through inhibition of the STAT3 pathway. Therefore, we suggested that ZER may act as a promising therapeutic drug for the treatment of breast cancer.

Zerumbone Induces G2/M Cell Cycle Arrest and Apoptosis via Mitochondrial Pathway in Jurkat cell Line

This investigation determined the anticancer properties of zerumbone (ZER) on the human T-cell (Jurkat) line using the MTT assay, microscopic evaluations, flow cytometric analyses, and caspase activity estimations. The results showed that ZER is selectively cytotoxic to Jurkat cells in a dose and time-dependent manner with IC50 of 11.9 ± 0.2, 8.6 ± 0.5 and 5.4 ± 0.4 μg/mL at 24, 48 and 72 hours of treatment, respectively. ZER did not produce an adverse effect on normal human peripheral blood mononuclear cells (PBMC). ZER is not as cytotoxic as doxorubicin, which imposed an inhibitory effect on Jurkat cells with IC50 of 2.1 ± 0.2, 1.8 ± 0.15, 1.5 ± 0.07 μg/mL after 24, 48 and 72 hours treatment, respectively. ZER significantly (P<0.05 ) arrested Jurkat cells at the G2/M phase of the cell cycle. The antiproliferative effect of ZER on Jurkat cells was through the apoptotic intrinsic pathway via the activation of caspase-3 and -9. The results showed that ZER can be further developed into a safe chemotherapeutic compound for the treatment of cancers, especially leukemia.

Notch2 activation is protective against anticancer effects of zerumbone in human breast cancer cells

We showed previously that zerumbone (ZER), a sesquiterpene isolated from subtropical ginger, inhibited in vitro (MCF-7 and MDA-MB-231cells) and in vivo (MDA-MB-231 cells) growth of human breast cancer cells in association with apoptosis induction. Here, we investigated the role of Notch receptors in anticancer effects of ZER (cell migration inhibition and apoptosis induction) using breast cancer cells. Western blotting was performed to determine protein expression changes. Effect of ZER on transcriptional activity of Notch was assessed by luciferase reporter assays. Transfection with small hairpin RNA or small interfering RNA was performed for knockdown of Notch2 or Presenilin-1 protein. Cell migration and apoptosis were quantitated by Boyden chamber assay and flow cytometry, respectively. Exposure of MDA-MB-231, MCF-7, and SUM159 cells to ZER resulted in increased cleavage of Notch2 in each cell line. On the other hand, levels of cleaved Notch1 and Notch4 proteins were decreased following ZER treatment. Increased cleavage of Notch2 in ZER-treated cells was accompanied by induction of Presenilin-1 protein and transcriptional activation of Notch. Inhibition of cell migration as well as apoptosis induction resulting from ZER exposure was significantly augmented by knockdown of Notch2 protein. ZER-mediated cleavage of Notch2 protein in MDA-MB-231 cells was markedly attenuated upon RNA interference of Presenilin-1. Knockdown of Presenilin-1 protein also resulted in escalation of ZER-induced apoptosis. The present study indicates that Notch2 activation by ZER inhibits its proapoptotic and anti-migratory response at least in breast cancer cells.

Assessment of cell cycle phase-specific effects of zerumbone on mitotically synchronous surface cultures of Physarum polycephalum

Zerumbone, a natural cyclic sesquiterpene, has been the focus of recent research as it has been found to exhibit selective toxicity towards cancer cells compared to normal cells. Studies on the cell cycle phase-specific effects of this interesting compound, however, remain sparse. Hence, concentration and time-dependent effects of zerumbone were evaluated employing a suitable model system, the naturally synchronous surface cultures of Physarum polycephalum. Zerumbone treatment in S, early, and late G2 phases resulted in G2 arrest. Early G2 phase exhibited the highest sensitivity (P < 0.001) to the compound. Protein profiles showed a complete inhibition of cyclin B1 expression following zerumbone treatment. Furthermore, FACS and comet analysis revealed that zerumbone inhibited DNA synthesis (P < 0.001) without being genotoxic at the concentrations tested. Differential display of mRNA showed distinct zerumbone-induced variations in transcript profiles, an analysis of which suggested a likely link between cellular networks involving stress-related gene expression and G2 arrest in P. polycephalum.

Biomedical properties of a natural dietary plant metabolite, zerumbone, in cancer therapy and chemoprevention trials

Zerumbone (ZER) is a naturally occurring dietary compound, present in many natural foods consumed today. The compound derived from several plant species of the Zingiberaceae family that has been found to possess multiple biomedical properties, such as antiproliferative, antioxidant, anti-inflammatory, and anticancer activities. However, evidence of efficacy is sparse, pointing to the need for a more systematic review for assessing scientific evidence to support therapeutic claims made for ZER and to identify future research needs. This review provides an updated overview of in vitro and in vivo investigations of ZER, its cancer chemopreventive properties, and mechanisms of action. Therapeutic effects of ZER were found to be scientifically plausible and could be explained partially by in vivo and in vitro pharmacological activities. Much of the research outlined in this paper will serve as a foundation to explain ZER anticancer bioactivity, which will open the door for the development of strategies in the treatment of malignancies using ZER.

Apoptosis mediated anti-proliferative effect of compound isolated from Cassia auriculata leaves against human colon cancer cell line

A compound was isolated from Cassia auriculata leaves and characterized by high-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC-MS), UV-vis spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The in vitro anticancer effect of the compound isolated from C. auriculata was evaluated in human colon cancer cells HCT 15 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cytotoxicity, nuclear morphology analysis and measurement of lactate dehydrogenase. The isolated compound 4-(2,5 dichlorobenzyl)-2,3,4,5,6,7 hexahydro7(4 methoxyphenyl)benzo[h][1,4,7] triazecin8(1H)-one showed 50% inhibition of HCT 15 cells when tested at 20μg/ml after 24h incubation. Cytotoxicity, nuclear morphology and lactate dehydrogenase assays clearly show potent anticancer activity of the isolated compound against colon cancer. Thus, the in vitro findings suggest that the compound isolated from C. auriculata leaves have potent anti-cancer properties with possible clinical applications.

Zerumbone inhibits angiogenesis by blocking NF-κB activity in pancreatic cancer

OBJECTIVES

Because angiogenesis is essential for tumor growth and metastasis, the development of antiangiogenic agents is an urgent issue in cancer treatment. Zerumbone, a component of subtropical ginger, has been shown to exhibit anticancer activities in various cancer cells; however, little is known about its biological mechanisms against angiogenesis in pancreatic cancer (PaCa). Here, we evaluated the effects of zerumbone on PaCa angiogenesis.

METHODS

The cytotoxicity of zerumbone in PaCa was measured using premix WST-1 cell proliferation assays. The influence of zerumbone on the angiogenic factors vascular endothelial growth factor and interleukin 8 was measured using the reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assays. Changes in nuclear factor-κB (NF-κB) activities were measured using NF-κB transcription factor assays. We also examined the effects of zerumbone on PaCa-induced angiogenesis using angiogenesis assays.

RESULTS

Zerumbone inhibited mRNA expression and protein secretion of angiogenic factors and NF-κB activity. Tube formation in human umbilical vein endothelial cells was enhanced by coculture with PaCa cells, and these enhancements were significantly inhibited by zerumbone treatment.

CONCLUSIONS

Zerumbone blocked the PaCa-associated angiogenesis through the inhibition of NF-κB and NF-κB-dependent proangiogenic gene products.

Zerumbone-loaded nanostructured lipid carrier induces G2/M cell cycle arrest and apoptosis via mitochondrial pathway in a human lymphoblastic leukemia cell line

This investigation evaluated the antileukemia properties of a zerumbone (ZER)-loaded nanostructured lipid carrier (NLC) prepared by hot high-pressure homogenization techniques in an acute human lymphoblastic leukemia (Jurkat) cell line in vitro. The apoptogenic effect of the ZER-NLC on Jurkat cells was determined by fluorescent and electron microscopy, Annexin V-fluorescein isothiocyanate, Tdt-mediated dUTP nick-end labeling assay, cell cycle analysis, and caspase activity. An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide) assay showed that ZER-NLC did not have adverse effects on normal human peripheral blood mononuclear cells. ZER-NLC arrested the Jurkat cells at G2/M phase with inactivation of cyclin B1 protein. The study also showed that the antiproliferative effect of ZER-NLC on Jurkat cells is through the intrinsic apoptotic pathway via activation of caspase-3 and caspase-9, release of cytochrome c from the mitochondria into the cytosol, and subsequent cleavage of poly (adenosine diphosphate-ribose) polymerase (PARP). These findings show that the ZER-NLC is a potentially useful treatment for acute lymphoblastic leukemia in humans.

Zerumbone from Ginger (Monoterpenoid)

Natural products have been regarded as safe and have been shown to have anticancer activities against a variety of cancer cell types. Zerumbone was initially isolated from the rhizome of a subtropical wild shampoo ginger (Zingiber zerumbet Smith) and was determined to be an anti-inflammatory agent. Carcinogenesis is a multistep process involving the transformation, survival, proliferation, invasion, and angiogenesis. The pathways associated with this process have been linked to inflammation. Zerumbone inhibits carcinogenesis via reduction of inflammatory signaling, such as nuclear factor-κB (NF-κB). In various cancers, zerumbone inhibits tumor proliferation, invasion, and angiogenesis by reducing NF-κB activity. In the near future, we should focus on both careful and accurate characterization of zerumbone and better elucidation of the molecular mechanisms involved in their actions. Furthermore, we should determine the efficacy of zerumbone by in vivo studies using proper animal models of cancer and demonstrate their safety and effectiveness in clinical trials.

Geraniin induces apoptotic cell death in human lung adenocarcinoma A549 cells in vitro and in vivo

Geraniin has previously been reported to possess extensive biological activity. In this study, we reported that geraniin is an inhibitor of tumor activity in vitro and in vivo. Geraniin suppressed the proliferation of A549 cells in a dose- and time-dependent manner. Geraniin arrested the cell cycle in the S phase and induced a significant accumulation of reactive oxygen species (ROS), as well as an increased percentage of cells with mitochondrial membrane potential (MMP) disruption. Western blot analysis showed that geraniin inhibited Bcl-2 expression and induced Bax expression to disintegrate the outer mitochondrial membrane and cause cytochrome c release. Mitochondrial cytochrome c release was associated with the activation of caspase-9 and caspase-3 cascades. Additionally, geraniin resulted in tumor growth inhibition in A549 xenografts. Our results indicate cytotoxic activity of geraniin towards cancer cells in vitro and in vivo.

Zerumbone inhibits tumor angiogenesis via NF-κB in gastric cancer

Zerumbone derived from a subtropical ginger, Zingiber zerumbet Smith, was previously reported to have antitumor growth and anti-inflammatory properties in some types of cancer. However, the effects of zerumbone against cancer angiogenesis have not been fully elucidated. In this study, we clarified the role of zerumbone in gastric cancer angiogenesis. We examined the expression of vascular endothelial growth factor (VEGF) in gastric cancer cell lines both in the basal state and following zerumbone treatment by real-time RT-PCR and enzyme-linked immunosorbent assay (ELISA). Changes in gastric cancer cell proliferation in response to zerumbone treatment were measured by WST-1 assay. Additionally, the effects of zerumbone on NF-κB activity were examined in AGS cells. Finally, the effects of zerumbone on angiogenesis in AGS cells were measured by in vitro angiogenesis assay in which human umbilical vein endothelial cells (HUVECs) and fibroblasts were cocultured with AGS cells. Among the 6 gastric cancer cell lines tested, AGS cells exhibited the highest expression of VEGF. Cell proliferation, VEGF expression and NF-κB activity in AGS cells were all significantly inhibited by zerumbone. Moreover, the tube formation area of HUVECs was increased by coculture with AGS cells, and this effect was inhibited by zerumbone. Both VEGF expression and NF-κB activity in AGS cells were reduced by treatment with zerumbone, thereby inhibiting angiogenesis. Thus, zerumbone may become a new anti-angiogenic and antitumor drug in the treatment of gastric cancer.