Epigallocatechin-3-gallate induces apoptosis and cell cycle arrest in HTLV-1-positive and -negative leukemia cells

The Effects of Green Tea Catechins in Hematological Malignancies

Green tea catechins are bioactive polyphenol compounds which have attracted significant attention for their diverse biological activities and potential health benefits. Notably, epigallocatechin-3-gallate (EGCG) has emerged as a potent apoptosis inducer through mechanisms involving caspase activation, modulation of Bcl-2 family proteins, disruption of survival signaling pathways and by regulating the redox balance, inducing oxidative stress. Furthermore, emerging evidence suggests that green tea catechins can modulate epigenetic alterations, including DNA methylation and histone modifications. In addition to their apoptotic actions, ROS signaling effects and reversal of epigenetic alterations, green tea catechins have shown promising results in promoting the differentiation of leukemia cells. This review highlights the comprehensive actions of green tea catechins and provides valuable insights from clinical trials investigating the therapeutic potential of green tea catechins in leukemia treatment. Understanding these multifaceted mechanisms and the outcomes of clinical trials may pave the way for the development of innovative strategies and the integration of green tea catechins into clinical practice for improving leukemia patient outcomes.

The influence of antioxidant dietary-derived polyphenolic combination on breast cancer: Molecular study

Breast cancer remains a leading cause of female mortality worldwide. Therefore, novel complementary treatments have been sought. Recently, there has been a growing interest in investigating the possible complementary effects of polyphenolic compounds against various malignancies. In the present study, using MCF-7 and MDA-MB-231 human breast adenocarcinoma cells, the anticancer efficacy of a polyphenolic mixture (PFM) was investigated. PFM is composed of curcumin, resveratrol, epigallocatechin gallate, and quercetin. PFM treatment led to a dose-dependent inhibition of cell proliferation, with IC₅₀ values of 25.9 ± 3 µg/ml and 29.4 ± 0.9 µg/ml for MCF-7 and MDA-MB-231 cells, respectively. In addition, PFM induced apoptosis in MDA-MB-231 cells and cell cycle arrest at the S phase in MCF-7 cells. Using RT-qPCR, PFM treatment was observed to result in significant downregulation of the oncogenic miR-155 (P < 0.05), as well as significant downregulation of the rate-limiting glycolytic enzyme, hexokinase 2 (HK2) (P < 0.05), while upregulating the expression of the zinc finger E-box binding homeobox 2 gene (P < 0.01). PFM was also found to exert an anti-migration effect in breast cancer cells using the wound healing assay, as well as significantly (P < 0.05) increasing the median survival of Ehrlich ascites carcinoma (EAC) tumor-bearing mice. These results suggest that PFM possesses potential antitumor effects against breast cancer. A possible mechanism of action could be due to PFM's effect in modulating the expression of the glycolytic enzyme HK2 through suppression of miR-155 in MCF-7 cells. Combining polyphenolic compounds that interact with one another could result in synergistic effects that potentially target various tumour hallmarks.

A comprehensive review of the influence of Epigallocatechin gallate on Sjögren's syndrome associated molecular regulators of exocytosis (Review)

Sjögren's syndrome (SS) is an autoimmune disorder that affects the salivary glands, leading to reduced secretory functions and oral and ocular dryness. The salivary glands are composed of acinar cells that are responsible for the secretion and production of secretory granules, which contain salivary components, such as amylase, mucins and immunoglobulins. This secretion process involves secretory vesicle trafficking, docking, priming and membrane fusion. A failure during any of the steps in exocytosis in the salivary glands results in the altered secretion of saliva. Soluble N-ethylmaleimide-sensitive-factor attachment protein receptors, actin, tight junctions and aquaporin 5 all serve an important role in the trafficking regulation of secretory vesicles in the secretion of saliva via exocytosis. Alterations in the expression and distribution of these selected proteins leads to salivary gland dysfunction, including SS. Several studies have demonstrated that green tea polyphenols, most notably Epigallocatechin gallate (EGCG), possess both anti-inflammatory and anti-apoptotic properties in normal human cells. Molecular, cellular and animal studies have indicated that EGCG can provide protective effects against autoimmune and inflammatory reactions in salivary glands in diseases such as SS. The aim of the present article is to provide a comprehensive and up-to-date review on the possible therapeutic interactions between EGCG and the selected molecular mechanisms associated with SS.

Two Worlds Colliding: The Interplay Between Natural Compounds and Non-Coding Transcripts in Cancer Therapy

Cancer is a devastating disease and has recently become the leading cause of death in western countries, representing an immense public health burden. When it comes to cancer treatment, chemotherapy is one of the main pillars, especially for advanced stage tumors. Over the years, natural compounds have emerged as one of the most valuable resources for new chemotherapies. It is estimated that more than half of the currently used chemotherapeutic agents are derived from natural compounds. Usually, natural compounds are discovered empirically and an important limitation of introducing new anti-cancer natural products is lack of knowledge with regard to their mechanism of action. Recent data has proven that several natural compounds may function via modulating the expression and function of non-coding RNAs (ncRNAs). NcRNAs are a heterogenous class of RNA molecules which are usually not translated into proteins but have an important role in gene expression regulation and are involved in multiple tumorigenic processes, including response/resistance to pharmacotherapy. In this review, we will discuss how natural compounds function via ncRNAs while summarizing the available data regarding their effects on over 15 types of cancer. Moreover, we will critically analyze the current advances and limitations in understanding the way natural compounds exert these health-promoting effects by acting on ncRNAs. Finally, we will propose several hypotheses that may open new avenues and perspectives regarding the interaction between natural compounds and ncRNAs, which could lead to improved natural compound-based therapeutic strategies in cancer.

Pien Tze Huang inhibits the growth of hepatocellular carcinoma cells by upregulating miR-16 expression

Hepatocellular carcinoma (HCC) is characterized by uncontrolled proliferation and the deregulation of apoptotic signaling, although its molecular pathogenesis is not fully characterized. The ability to inhibit excessive proliferation and induce the apoptosis of cancer cells are crucial characteristics of anticancer drugs. Pien Tze Huang (PZH) is a widely used traditional Chinese medicine for the treatment of various types of cancer, and has exhibited promising therapeutic effects in clinical trials of HCC. However, the underlying mechanisms for its action are unclear. In the present study, the aim was to explore the effect of PZH on the proliferation and apoptosis of the BEL-7402 HCC cell line, and the associated mechanisms. PZH treatment significantly inhibited BEL-7402 cell viability, confluence and clonogenicity, inducing cell cycle arrest and promoting apoptosis. In addition, PZH treatment suppressed the expression of the pro-proliferative genes cyclin D1 and cyclin-dependent kinase 4, and decreased the expression of the anti-apoptotic gene Bcl-2. PZH treatment also upregulated the expression of a key microRNA (miR), miR-16. The study demonstrated that PZH can effectively inhibit cancer cell proliferation and induce apoptosis in BEL-7402 HCC cells via the upregulation of the tumor suppressor miR-16.

THE HERBAL MIXTURE XIAO-CHAI-HU TANG (XCHT) INDUCES APOPTOSIS OF HUMAN HEPATOCELLULAR CARCINOMA HUH7 CELLS IN VITRO AND IN VIVO

Background:

Xiao-Chai-Hu Tang (XCHT) is an extract of seven herbs with anticancer properties, but its mechanism of action is unknown. In this study, we evaluated XCHT-treated hepatocellular carcinoma (HCC) for anti-proliferative and pro-apoptotic effects.

Materials and Methods:

Using a hepatic cancer xenograft model, we investigated the in vivo efficacy of XCHT against tumor growth by evaluating tumor volume and weight, as well as measuring apoptosis and cellular proliferation within the tumor. To study the effects of XCHT in vitro, we measured the cell viability of XCHT-treated Huh7 cells, as well as colony formation and apoptosis. To identify a potential mechanism of action, the gene and protein expression levels of Bax, Bcl-2, CDK4 and cyclin-D1 were measured in XCHT-treated Huh7 cells.

Results:

We found that XCHT reduced tumor size and weight, as well as significantly decreased cell viability both in vivo and in vitro. XCHT suppressed the expression of the proliferation marker Ki-67 in HCC tissues and inhibited Huh7 colony formation. XCHT induced apoptosis in HCC tumor tissues and in Huh7 cells. Finally, XCHT altered the expression of Bax, Bcl-2, CDK4 and cyclin-D1, which halted cell proliferation and promoted apoptosis.

Conclusion:

Our data suggest that XCHT enhances expression of pro-apoptotic pathways, resulting in potent anticancer activity.

Established Human Cell Lines as Models to Study Anti-leukemic Effects of Flavonoids

Despite the extensive work on pathological mechanisms and some recent advances in the treatment of different hematological malignancies, leukemia continues to present a significant challenge being frequently considered as incurable disease. Therefore, the development of novel therapeutic agents with high efficacy and low toxicity is urgently needed to improve the overall survival rate of patients. In this comprehensive review article, the current knowledge about the anticancer activities of flavonoids as plant secondary polyphenolic metabolites in the most commonly used human established leukemia cell lines (HL-60, NB4, KG1a, U937, THP-1, K562, Jurkat, CCRF- CEM, MOLT-3, and MOLT-4) is compiled, revealing clear anti-proliferative, pro-apoptotic, cell cycle arresting, and differentiation inducing effects for certain compounds. Considering the low toxicity of these substances in normal blood cells, the presented data show a great potential of flavonoids to be developed into novel anti-leukemia agents applicable also in the malignant cells resistant to the current conventional chemotherapeutic drugs.

Anticancer Efficacy of Polyphenols and Their Combinations

Polyphenols, found abundantly in plants, display many anticarcinogenic properties including their inhibitory effects on cancer cell proliferation, tumor growth, angiogenesis, metastasis, and inflammation as well as inducing apoptosis. In addition, they can modulate immune system response and protect normal cells against free radicals damage. Most investigations on anticancer mechanisms of polyphenols were conducted with individual compounds. However, several studies, including ours, have indicated that anti-cancer efficacy and scope of action can be further enhanced by combining them synergistically with chemically similar or different compounds. While most studies investigated the anti-cancer effects of combinations of two or three compounds, we used more comprehensive mixtures of specific polyphenols and mixtures of polyphenols with vitamins, amino acids and other micronutrients. The mixture containing quercetin, curcumin, green tea, cruciferex, and resveratrol (PB) demonstrated significant inhibition of the growth of Fanconi anemia head and neck squamous cell carcinoma and dose-dependent inhibition of cell proliferation, matrix metalloproteinase (MMP)-2 and -9 secretion, cell migration and invasion through Matrigel. PB was found effective in inhibition of fibrosarcoma HT-1080 and melanoma A2058 cell proliferation, MMP-2 and -9 expression, invasion through Matrigel and inducing apoptosis, important parameters for cancer prevention. A combination of polyphenols (quercetin and green tea extract) with vitamin C, amino acids and other micronutrients (EPQ) demonstrated significant suppression of ovarian cancer ES-2 xenograft tumor growth and suppression of ovarian tumor growth and lung metastasis from IP injection of ovarian cancer A-2780 cells. The EPQ mixture without quercetin (NM) also has shown potent anticancer activity in vivo and in vitro in a few dozen cancer cell lines by inhibiting tumor growth and metastasis, MMP-2 and -9 secretion, invasion, angiogenesis, and cell growth as well as induction of apoptosis. The presence of vitamin C, amino acids and other micronutrients could enhance inhibitory effect of epigallocatechin gallate (EGCG) on secretion of MMPs. In addition, enrichment of NM with quercetin (EPQ mix) enhanced anticancer activity of NM in vivo. In conclusion, polyphenols, especially in combination with other polyphenols or micronutrients, have been shown to be effective against multiple targets in cancer development and progression, and should be considered as safe and effective approaches in cancer prevention and therapy.

In vitro and in vivo inhibition of human Fanconi anemia head and neck squamous carcinoma by a phytonutrient combination

Head and neck squamous cell carcinoma (HNSCC) and acute myeloid leukemia are the major causes of mortality and morbidity in Fanconi anemia (FA) patients. The objective of this study was to investigate the antineoplastic activity of PB, an antineoplastic nutrient mixture (containing quercetin, curcumin, green tea, cruciferex and resveratrol) on human FA HNSCC in vitro and in vivo. Human FA HNSCC cell line OHSU-974 (Fanconi Anemia Research Fund) was cultured in RPMI medium supplemented with 20% FBS and anti-biotics. At near confluence, cells were treated in triplicate with different concentrations of PB: 0, 10, 25, 50, 75 and 100 µg/ml. Cells were also treated with PMA to induce MMP-9 activity. Cell proliferation was detected by MTT assay, secretion of MMPs by gelatinase zymography, invasion through Matrigel, migration by scratch test and morphology by hematoxylin and eosin (H&E) staining. In vivo, athymic male nude mice (n=12) were inoculated with 3x106 OHSU-974 cells subcutaneously and randomly divided into two groups: group A was fed a regular diet and group B a regular diet supplemented with 1% PB. Four weeks later, the mice were sacrificed and their tumors were excised, weighed and processed for histology. NM inhibited the growth of OHSU-974 tumor by 67.6% (p<0.0001) and tumor burden by 63.6% (p<0.0001). PB demonstrated dose-dependent inhibition of cell proliferation, with 27% (p=0.0003) and 48% (p=0.0004) toxicity at 75 and 100 µg/ml, respectively. Zymography revealed MMP-2 and PMA-induced MMP-9 secretion. PB suppressed secretion of both MMPs in a dose-dependent manner, with total block of both at 50 µg/ml. PB inhibited cell migration (by scratch test) and OHSU-974 invasion through Matrigel in a dose-dependent fashion with total block at 50 µg/ml. H&E staining showed no morphological changes below 50 µg/ml. The results suggest that PB has potential therapeutic use in the treatment of human FA HNSCC.

pecific nutrient combination effects on tax, NF- κB and MMP-9 in human T-cell lymphotropic virus -1 positive malignant T-lymphocytes

BACKGROUND

Adult T-cell Leukemia (ATL) is a disease with no known cure. The disease manifests itself as an aggressive proliferation of CD4+ cells with the human T-cell Lymphotropic virus type 1 (HTLV-1). The leukemogenesis of the virus is mainly attributed to the viral oncoprotein. Tax activates the Nuclear Factor kappa B (NF-κB) which stimulates the activity and expression of the matrix metalloproteinase-9 (MMP-9). The objective of this study was to investigate the efficacy of a specific nutrient synergy (SNS) on proliferation, Tax expression, NF-κB levels as well as on MMP-9 activity and expression both at the transcriptional and translational levels in two HTLV-1 positive cell lines, HuT-102 and C91-PL at 48h and 96h of incubation. Cytotoxicity of Epigallocatechin-3-gallate (EGCG) was assayed using CytoTox 96 Non-radioactive and proliferation was measured using Cell Titer96TM Nonradioactive Cell Proliferation kit (MTT- based assay). Enzyme linked immunosorbant assay (ELISA) and electrophoretic mobility shift assay (EMSA) were used to assess the effect of SNS on NF-κB mobility. Zymography was used to determine the effects of SNS on the activity and secretion of MMP-9. The expression of MMP-9 was done using RT-PCR at the translational level and Immunoblotting at the transcriptional level.

RESULTS

A significant inhibition of proliferation was seen in both cell lines starting at a concentration of 200μg/ml and in a dose dependent manner. SNS induced a dose dependent decrease in Tax expression, which was paralleled by a down-regulation of the nuclearization of NF-κB. This culminated in the inhibition of the activity of MMP-9 and their expression both at the transcriptional and translational levels.

CONCLUSIONS

The results of this study indicate that a specific nutrient synergy targeted multiple levels pertinent to the progression of ATL. Its activity was mediated through the NF-κB pathway, and hence has the potential to be integrated in the treatment of this disease as a natural potent anticancer agent.

A short-term preservation of human cultured periosteal sheets, osteogenic grafting materials, using a commercial preservation solution containing epigallocatechin-3-gallate (Theliokeep(®)) under hypothermic conditions

In the past decade, it has increasingly been reported that epigallocatechin-3-gallate (EGCG), a major catechin derivative extracted from Green tea, has various bioactivities, including a cell-protective action on mammalian cells and tissues. In this study, we have tested a commercial preservation solution containing EGCG (Theliokeep(®)) in both two- and three-dimensional cultures of human periosteal sheets, which have been used as an osteogenic grafting material for periodontal regenerative therapy. When periosteal sheets were 3D-cultured on collagen mesh, cell viability was maintained for 2 days using the hypothermic EGCG preservation solution. Replenishment of EGCG solution with 2-day intervals prevented the time-dependent decline in cell viability at 3 days and later. As observed in nonpreserved control cultures, most cells were positive for proliferating cell-nuclear antigen (PCNA) in the cultures preserved at 4°C in the EGCG solution, whereas PCNA-negative cells were increased in the cultures preserved at 4°C in the MesenPRO medium. In periosteal sheets 2D-cultured in plastic dishes, the EGCG solution occasionally was associated with vacuole formation in the cytoplasm, but cells could again expand in the culture medium at 37°C. As observed in the nonpreserved periosteal sheets control, the osteogenic induction upregulated alkaline phosphatase in those cells and tissues preserved in the EGCG solution. The EGCG solution protected cells from the cold shock-induced membrane phospholipid peroxidation. Our data suggest that the EGCG solution acts as an antioxidant to protect periosteal cells from cold shock and preserves cells under chilled conditions. The limited period of preservation time could be expanded by repeating replenishment of the EGCG solution or by optimizing the formula to be more favorable for human periosteal sheets without sacrificing cell viability. This methodology of preserving human cultured periosteal sheets with EGCG would be expected to support and spread the clinical use of regenerative therapy with autologous periosteal sheets.

Overexpression of miR-126 sensitizes osteosarcoma cells to apoptosis induced by epigallocatechin-3-gallate

Background

miR-126 plays an important role in the proliferation, invasion, migration, and chemotherapeutics resistance in cancer. Epigallocatechin-3-gallate (EGCG), as the major polyphenolic constituent present in green tea, is a promising anticancer agent. However, the role of miR-126 in EGCG anticancer remains unclear. Here, we investigated the effects of miR-126 and EGCG on cell viability, apoptosis, cell cycle distribution of osteosarcoma cells and the sensitization of miR-126 on osteosarcoma cells to EGCG.

Methods

The cell viability, apoptosis and cycle distribution were analyzed using MTT assay and flow cytometry.

Results

Our results showed that EGCG (0.025, 0.05, 0.1, 0.2 g/L) suppresses proliferation of osteosarcoma MG63 and U2OS cells in a concentration-dependent and time-dependent manner and the inhibitory effects of 0.05 g/L EGCG on U2OS cells were roughly equivalent to 20 μM cisplatin (DDP); miR-126 could promote apoptosis and inhibit proliferation in U2OS cells but without significant effects on cell cycle G1 phase arrest; EGCG suppressed proliferation of U2OS cells through induction of cell cycle G1 arrest and apoptotic death; overexpression of miR-126 enhanced the inhibitory effects of EGCG on proliferation in U2OS cells via promotion of apoptosis.

Conclusions

Our results demonstrate that enhanced expression of miR-126 increased the sensitivity of osteosarcoma cells to EGCG through induction of apoptosis.

Epigallocatechin-3-gallate inhibits tax-dependent activation of nuclear factor kappa B and of matrix metalloproteinase 9 in human T-cell lymphotropic virus-1 positive leukemia cells

Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol molecule from green tea and is known to exhibit antioxidative as well as tumor suppressing activity. In order to examine EGCG tumor invasion and suppressing activity against adult T-cell leukemia (ATL), two HTLV-1 positive leukemia cells (HuT-102 and C91- PL) were treated with non-cytotoxic concentrations of EGCG for 2 and 4 days. Proliferation was significantly inhibited by 100 μM at 4 days, with low cell lysis or cytotoxicity. HTLV-1 oncoprotein (Tax) expression in HuT- 102 and C91-PL cells was inhibited by 25 μM and 125 μM respectively. The same concentrations of EGCG inhibited NF-kB nuclearization and stimulation of matrix metalloproteinase-9 (MMP-9) expression in both cell lines. These results indicate that EGCG can inhibit proliferation and reduce the invasive potential of HTLV-1- positive leukemia cells. It apparently exerted its effects by suppressing Tax expression, manifested by inhibiting the activation of NF-kB pathway and induction of MMP-9 transcription in HTLV-1 positive cells.

Nitidine chloride inhibits hepatic cancer growth via modulation of multiple signaling pathways

Background

The development of hepatic cancer is tightly regulated by multiple intracellular signaling pathways. Therefore, most currently-used anti-tumor agents, which typically target single intracellular pathway, might not always be therapeutically effective. Additionally, long-term use of these agents probably generates drug resistance and unacceptable adverse effects. These problems increase the necessity for the development of new chemotherapeutic approaches. Nitidine chloride (NC), a natural benzophenanthridine alkaloid, has been shown to inhibit cancer growth via induction of cell apoptosis and suppression of cancer angiogenesis. But the precise mechanisms of its tumorcidal activity are not well understood.

Methods

To further elucidate the precise mechanisms of its anti-tumor activity, using a hepatic cancer mouse xenograft model, the human hepatic cancer cell lines (HepG2, HCCLM3, Huh7), and umbilical vein endothelial cells (HUVEC), here we evaluate the effect of NC on tumor growth in vivo and in vitro and investigated the underlying molecular mechanisms.

Results

We found that NC treatment resulted in significant decrease in tumor volume and tumor weight respectively, but didn’t affect body weight changes. Additionally, NC treatment dose- and time-dependently reduced the cell viability of all three hepatic cell lines. Moreover, NC suppressed the activation of STAT3, ERK and SHH pathways; and altered the expression of critical target genes including Bcl-2, Bax, Cyclin D1, CDK4, VEGF-A and VEGFR2. These molecular effects resulted in the promotion of apoptosis, inhibition of cell proliferation and tumor angiogenesis.

Conclusions

Our findings suggest that NC possesses a broad range of anti-cancer activities due to its ability to affect multiple intracellular targets, suggesting that NC could be a novel multi-potent therapeutic agent for the treatment of hepatic cancer and other cancers.

Effects of nutrients on matrix metalloproteinases in human T-lymphotropic virus type 1 positive and negative malignant T-lymphocytes

Experimental and clinical studies have revealed the effectiveness of a specific nutrient synergy (SNS) mixture composed of ascorbic acid (AA), lysine, proline, arginine, epigallocatechin gallate (EGCG) and other micronutrients in targeting crucial physiological mechanisms involved in cancer progression and metastasis. HTLV-1 causes adult T-cell leukemia (ATL). The spread and metastases of ATL as well as other tumors has been associated with matrix metalloproteinases, especially the gelatinases MMP-2 and MMP-9. The objective of this study was to investigate whether SNS, AA and EGCG affects the gelatinolytic activity of MMP-2 and its transcriptional and translational levels in HTLV-1-positive and -negative malignant T-cells. The results indicated that SNS and EGCG caused a dose-dependent decline in the activity, transcription and translation of MMP-2 after treatment with SNS and EGCG, while AA was only able to inhibit the activity at maximum doses tested and to some extent, the protein expression levels of MMP-2, without affecting their transcriptional levels. The highest activity was noted in the case of SNS which is likely to be due to a synergistic effect of the different constituents in the formulation. These results point towards the potential integration of SNS in the anti-invasive treatment of ATL and related diseases.

Spica prunellae promotes cancer cell apoptosis, inhibits cell proliferation and tumor angiogenesis in a mouse model of colorectal cancer via suppression of stat3 pathway

Background

Constitutive activation of STAT3 is one of the major oncogenic pathways involved in the development of various types of malignancies including colorectal cancer (CRC); and thus becomes a promising therapeutic target. Spica Prunellae has long been used as an important component in many traditional Chinese medicine formulas to clinically treat CRC. Previously, we found that Spica Prunellae inhibits CRC cell growth through mitochondrion-mediated apoptosis. Furthermore, we demonstrated its anti-angiogenic activities in vivo and in vitro. To further elucidate the precise mechanism of the potential tumoricidal activity of Spica Prunellae, using a CRC mouse xenograft model, in this study we evaluated its therapeutic efficacy against CRC and investigated the underlying molecular mechanisms.

Methods

CRC mouse xenograft model was generated by subcutaneous injection of human colon carcinoma HT-29 cells into nude mice. Animals were given intra-gastric administration with 6 g/kg of the ethanol extract of Spica Prunellae (EESP) daily, 5 days a week for 16 days. Body weight and tumor growth were measured every two days. Tumor growth in vivo was determined by measuring the tumor volume and weight. HT-29 cell viability was examined by MTT assay. Cell apoptosis and proliferation in tumors from CRC xenograft mice was evaluated via immunohistochemical staining (IHS) for TUNEL and PCNA, and the intratumoral microvessel density (MVD) was examined by using IHS for the endothelial cell-specific marker CD31. The activation of STAT3 was evaluated by determining its phosphorylation level using IHS. The mRNA and protein expression of Bcl-2, Bax, Cyclin D1, VEGF-A and VEGFR2 was measured by RT-PCR and IHS, respectively.

Results

EESP treatment reduced tumor volume and tumor weight but had no effect on body weight change in CRC mice; decreased HT-29 cell viability in a dose-dependent manner, suggesting that EESP displays therapeutic efficacy against colon cancer growth in vivo and in vitro, without apparent toxicity. In addition, EESP significantly inhibited the phosphorylation of STAT3 in tumor tissues, indicating its suppressive action on the activation of STAT3 signaling. Consequently, the inhibitory effect of EESP on STAT3 activation resulted in an increase in the pro-apoptotic Bax/Bcl-2 ratio, decrease in the expression of the pro-proliferative Cyclin D1 and CDK4, as well as down-regulation of pro-angiogenic VEGF-A and VEGFR-2 expression. Finally, these molecular effects led to the induction of apoptosis, the inhibition of cell proliferation and tumor angiogenesis.

Conclusions

Spica Prunellae possesses a broad range of anti-cancer activities due to its ability to affect STAT3 pathway, suggesting that Spica Prunellae could be a novel potent therapeutic agent for the treatment of CRC.

(-)-Epigallocatechin-3-gallate induces apoptosis and inhibits invasion and migration of human cervical cancer cells

Invasion and metastasis are the major causes of cancer-related death. Pharmacological or therapeutic interventions such as chemoprevention of the progression stages of neoplastic development could result in substantial reduction in the incidence of cancer mortality. (-)-Epigallocatechin-3-gallate (EGCG), a promising chemopreventive agent, has attracted extensive interest for cancer therapy utilizing its antioxidant, anti- proliferative and inhibitory effects on angiogenesis and tumor cell invasion. In this study, we assessed the influence of EGCG on the proliferative potential of HeLa cells by cell viability assay and authenticated the results by nuclear morphological examination, DNA laddering assay and cell cycle analysis. Further we analyzed the anti-invasive properties of EGCG by wound migration assay and gene expression of MMP-9 and TIMP-1 in HeLa cells. Our results indicated that EGCG induced growth inhibition of HeLa cells in a dose- and time- dependent manner. It was observed that cell death mediated by EGCG was through apoptosis. Interestingly, EGCG effectively inhibited invasion and migration of HeLa cells and modulated the expression of related genes (MMP-9 and TIMP-1) . These results indicate that EGCG may effectively suppress promotion and progression stages of cervical cancer development.

Chemical constituents of volatile oil from Pyrolae herba and antiproliferative activity against SW1353 human chondrosarcoma cells

The objective of the present study was to identify chemical constituents of volatile oil from Pyrolae herba (PHVO) and evaluate the antiproliferative activity of PHVO against SW1353 human chondrosarcoma cells. The volatile oil from Pyrolae herba was prepared by hydrodistillation and characterized by gas chromatography-mass spectroscopy (GC-MS). A total of 12 components in PHVO were identified representing 81.62% of the total integrated chromatographic peaks. The major compounds were found to be n-hexadecanoic acid (29.29%), cedrol (17.08%), 6,10,14-trimethyl-2-pentadecanone (9.59%) and cis-9-octadecadienoic acid (8.23%). The antiproliferative activity of PHVO against SW1353 cells was investigated using MTT assay, flow cytometry and western blot analysis. Our results demonstrated that PHVO inhibited SW1353 cell viability in a dose- and time-dependent manner. Furthermore, PHVO treatment decreased the number of cells entering the S phase and caused a reduction in the expression of cyclin D1, cyclin-dependent kinase (CDK)4 and CDK6, whereas it caused an increase in the expression of p21. PHVO demonstrated potent antitumor activity against SW1353 cells, suggesting its potential use as a therapeutic agent in the treatment of chondrosarcoma.

Cancer chemoprevention by polyphenols and their potential application as nanomedicine

Today cancer is a leading cause of death among the developed countries. Its highly complex nature makes it difficult to understand as it entails multiple cellular physiological systems such as cell signaling and apoptosis. The biggest challenges faced by cancer chemoprevention/chemotherapy is maintaining drug circulation and avoiding multidrug resistance. Overall there is modest evidence regarding the protective effects of nutrients from supplements against a number of cancers. Numerous scientific literatures available advocate the use of polyphenols for chemoprevention. Some groups have also suggested use of combination of nutrients in cancer prevention. However, we have yet to obtain the desired results in the line of cancer chemotherapy research. Nanotechnology can play a pivotal role in cancer treatment and prevention. Moreover, nanoparticles can be modified in various ways to prolong circulation, enhance drug localization, increase drug efficacy, and potentially decrease the chances of multidrug resistance. In this communication, we will cover the use of various polyphenols and nutrients in cancer chemoprevention. The application of nanotechnology in this regard will also be included. In view of available reports on the potential of nanoparticles, we suggest their usage along with different combination of nutrients as cancer chemotherapeutic agents.

Epigallocatechin-3-gallate up-regulates tumor suppressor gene expression via a reactive oxygen species-dependent down-regulation of UHRF1

Ubiquitin-like containing PHD and Ring finger 1 (UHRF1) contributes to silencing of tumor suppressor genes by recruiting DNA methyltransferase 1 (DNMT1) to their hemi-methylated promoters. Conversely, demethylation of these promoters has been ascribed to the natural anti-cancer drug, epigallocatechin-3-gallate (EGCG). The aim of the present study was to investigate whether the UHRF1/DNMT1 pair is an important target of EGCG action. Here, we show that EGCG down-regulates UHRF1 and DNMT1 expression in Jurkat cells, with subsequent up-regulation of p73 and p16(INK4A) genes. The down-regulation of UHRF1 is dependent upon the generation of reactive oxygen species by EGCG. Up-regulation of p16(INK4A) is strongly correlated with decreased promoter binding by UHRF1. UHRF1 over-expression counteracted EGCG-induced G1-arrested cells, apoptosis, and up-regulation of p16(INK4A) and p73. Mutants of the Set and Ring Associated (SRA) domain of UHRF1 were unable to down-regulate p16(INK4A) and p73, either in the presence or absence of EGCG. Our results show that down-regulation of UHRF1 is upstream to many cellular events, including G1 cell arrest, up-regulation of tumor suppressor genes and apoptosis.

Pien Tze Huang inhibits the proliferation of human colon carcinoma cells by arresting G1/S cell cycle progression

Pien Tze Huang (PZH), a well-known traditional Chinese formula prescribed 450 years ago in the Ming Dynasty, has been used in China and Southeast Asia for centuries as a folk remedy for various types of cancer, including colorectal cancer (CRC). Recently, we reported that PZH is capable of inhibiting colon cancer growth both in vivo and in vitro via the promotion of apoptosis and inhibition of tumor angiogenesis. To elucidate the mechanism of the tumoricidal activity of PZH, its effect on the proliferation of human colon carcinoma Caco-2 cells was evaluated and the underlying molecular mechanism was investigated. Results showed that PZH inhibited Caco-2 cell viability and survival in a dose- and/or time-dependent manner. In addition, PZH treatment was found to block the G1/S cell cycle progression. Moreover, PZH suppressed the mRNA and protein expression of pro-proliferative Cyclin D1 and CDK4. Findings of the present study suggest that inhibition of cell proliferation via the G1/S cell cycle arrest is a potential mechanism by which PZH can be effective in the treatment of cancer.

WITHDRAWN: Epigallocatechin-3-gallate up-regulates tumor suppressor gene expression via a reactive oxygen species-dependent down-regulation of UHRF1

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Neuroepithelial transforming protein 1 short interfering RNA-mediated gene silencing with microbubble and ultrasound exposure inhibits the proliferation of hepatic carcinoma cells in vitro

OBJECTIVES

Short interfering RNA (siRNA) has been used to knock down the expression of targeted genes in a process known as RNA interference. However, the key to RNA interference is the efficient intracellular delivery of the siRNA. In this study, we sought to enhance the efficiency of transduction and find a novel therapy for hepatic carcinoma.

METHODS

Three types of neuroepithelial transforming protein 1 (NET-1) siRNAs (labeled fluorescent) were designed and transduced into HepG2 cells. Then the most effective one in silencing NET-1 was determined. The HepG2 cells were divided into 5 groups: untreated control; delivery of siRNA; delivery of siRNA using Lipofectamine 2000 (Invitrogen, Carlsbad, CA; group L); delivery of siRNA using ultrasound exposure and microbubbles (group US); and delivery of siRNA using Lipofectamine, ultrasound exposure, and microbubbles (group LUS). The efficiency of siRNA transfer was determined by detection of luciferase activity on microscopy; NET-1 expression was assayed by reverse transcription-polymerase chain reaction and western blotting; and proliferation investigations of the HepG2 cells were performed. RESULTS- The transfection efficiency of microbubbles combined with ultrasound exposure was nearly equal to Lipofectamine-mediated transfection (P = .609). More importantly, the combination of Lipofectamine, microbubbles, and ultrasound exposure effectively reduced NET-1 expression compared with the other groups (P < .01). Furthermore, the proliferation of cells in groups L, US, and LUS was visibly inhibited between 24 and 72 hours.

CONCLUSIONS

The use of a microbubble contrast agent combined with ultrasound exposure could be a potent physical method for increasing gene delivery efficiency. This technique is a promising nonviral approach that can be used in liver cancer.

Hedyotis diffusa Willd inhibits colorectal cancer growth in vivo via inhibition of STAT3 signaling pathway

Signal Transducer and Activator of Transcription 3 (STAT3), a common oncogenic mediator, is constitutively activated in many types of human cancers; therefore it is a major focus in the development of novel anti-cancer agents. Hedyotis diffusa Willd has been used as a major component in several Chinese medicine formulas for the clinical treatment of colorectal cancer (CRC). However, the precise mechanism of its anti-tumor activity remains largely unclear. Using a CRC mouse xenograft model, in the present study we evaluated the effect of the ethanol extract of Hedyotis diffusa Willd (EEHDW) on tumor growth in vivo and investigated the underlying molecular mechanisms. We found that EEHDW reduced tumor volume and tumor weight, but had no effect on body weight gain in CRC mice, demonstrating that EEHDW can inhibit CRC growth in vivo without apparent adverse effect. In addition, EEHDW treatment suppressed STAT3 phosphorylation in tumor tissues, which in turn resulted in the promotion of cancer cell apoptosis and inhibition of proliferation. Moreover, EEHDW treatment altered the expression pattern of several important target genes of the STAT3 signaling pathway, i.e., decreased expression of Cyclin D1, CDK4 and Bcl-2 as well as up-regulated p21 and Bax. These results suggest that suppression of the STAT3 pathway might be one of the mechanisms by which EEHDW treats colorectal cancer.

Comparative in vitro bioactivities of tea extracts from six species of Ardisia and their effect on growth inhibition of HepG2 cells

AIM OF THE STUDY

Ardisia species, notably A. compressa, are used in some regions of the world as food or in traditional medicine for prevention and treatment of certain health conditions including liver disease. We investigated the chemical composition and relative anticancer potential of six Ardisia species [A. japonica (AJ), A. escallonioides (AES), A. mamillata (AM), A. compressa (AC), A. crenata (ACR), and A. elliptica (AE)].

MATERIALS AND METHODS

Antioxidant capacity, DNA human topoisomerase II catalytic inhibition, and cytotoxicity on human liver cancer cells (HepG2) were determined in vitro in tea extracts of the 6 Ardisia species evaluated. Selected pure phenolic compounds present in Ardisia species were also evaluated.

RESULTS

AC showed the highest topoisomerase II catalytic inhibition (IC(50)=12 microg/ml) and cytotoxicity (IC(50)=117 microg/ml) against HepG2 cells, followed by ACR and AJ. Total polyphenols ranged from 21 to 72 mg equivalents of gallic acid (GA)/g solid extract (SE). LC-MS analysis revealed the presence of GA, quercetin derivatives, ardisenone, ardisiaquinone, ardisianone, bergenin, norbergenin, and embelin. However, neither total polyphenol concentration nor antioxidant capacity correlated with anticancer capacity. Significant HepG2 cytotoxicity was also achieved by bergenin (IC(50)=18 microM) and embelin (IC(50)=120 microM). AC, bergenin, embelin, and quercetin showed a tendency to accumulate cells in the G1 phase and reduced G2/M leading to apoptosis.

CONCLUSIONS

Although the mechanism is not entirely clear, AC, ACR, and AJ are the Ardisia species with the greatest anticancer potential against liver cancer cells in vitro and deserve further investigation.

Induction of apoptosis in human hepatocarcinoma SMMC-7721 cells in vitro by flavonoids from Astragalus complanatus

AIM OF THE STUDY

Flavonoids extracted from the seeds of Astragalus complanatus R.Br. reduce the proliferation of many cancer cells. The present study was carried out to evaluate the effects of these flavonoids from Astragalus complanatus (FAC) on human hepatocarcinoma cell viability and apoptosis and to investigate its mechanisms of action in SMMC-7721 cells.

MATERIALS AND METHODS

Cell viability was measured using the MTT assay. To detect apoptotic cells, SMMC-7721 cells treated with FAC were stained with Hoechst 33258 and subjected to agarose gel electrophoresis. Quantitative detection of apoptotic cells was performed by flow cytometry. The effects of FAC on apoptosis and cell cycle regulatory genes and proteins in SMMC-7721 cells were examined using an S series apoptosis and cell cycle gene array and Western blot analysis.

RESULTS

The growth of SMMC-7721 and HepG2 cells was inhibited by treatment with FAC. Cell death induced by FAC was characterized by nuclear condensation and DNA fragmentation. Moreover, the cell cycle was arrested in the G0/G1 and S phases in FAC-treated SMMC-7721 cells. A sub-G1 peak with reduced DNA content was also formed. The activity of caspase-3 was significantly increased following FAC treatment. Microarray data indicated that the expression levels of 76 genes were changed in SMMC-7721 cells treated with FAC: 35 genes were up-regulated and 41 were down-regulated. Western blot analysis showed that caspase-3, caspase-8, Bax, P21, and P27 protein levels in SMMC-7721 cells were increased after 48 h of FAC treatment, while cyclinB1, cyclinD1, CDK1, and CDK4 protein levels were decreased.

CONCLUSIONS

These results suggest that FAC may play an important role in tumor growth suppression by inducing apoptosis in human hepatocarcinoma cells via mitochondria-dependent and death receptor-dependent apoptotic pathways.

Anticancer effects of phenoxazine derivatives revealed by inhibition of cell growth and viability, disregulation of cell cycle, and apoptosis induction in HTLV-1-positive leukemia cells

Adult T-cell leukemia (ATL) is a malignant tumor of human CD4(+) T cells infected with a human retrovirus, T lymphotropic virus type-1 (HTLV-1). The aim of the present study was to investigate the apoptotic effects of phenoxazines, 2-amino-4,4alpha-dihydro-4alpha,7-dimethyl-3H-phenoxazine-3-one (Phx-1), 3-amino-1,4alpha-dihydro-4alpha,8-dimethyl-2H-phenoxazine-2-one (Phx-2), and 2-aminophenoxazine-3-one (Phx-3) on a T cell leukemia cell line from ATL patients, MT-1 cells; HTLV-1 transformed T-cell lines, HUT-102 cells and MT-2 cells; and an HTLV-1-negative rat sarcoma cell line, XC cells. Among these phenoxazines, Phx-3 at concentrations of less than 10 microg/ml extensively inhibited growth and cell viability; arrested cell cycles at sub G(0)/G(1) phase; and augmented apoptosis of MT-1, HUT-102, and MT-2 cells. However, these phenoxazines did not affect the cell viability of an HTLV-1-negative rat sarcoma cell line, XC cells, and phytohemaggutinin-activated human peripheral blood mononuclear cells, although they markedly inhibited the growth of these cells. The transmission of HTLV-1 from HTLV-1-positive cells (MT-2 cells) to HTLV-1-negative cells (XC cells) was considered to be prevented by Phx-1, Phx-2, or Phx-3 because the syncytium formation between these cells was inhibited markedly in the presence of these phenoxazines. The present results suggest that Phx-1, Phx-2, and, in particular, Phx-3 may be useful as therapeutic agents against ATL, which is extremely refractory to current therapies.

Enhancement of survivin gene downregulation and cell apoptosis by a novel combination: liposome microbubbles and ultrasound exposure

Ultrasound-mediated microbubble destruction (sonoporation) is an efficient and safe nonviral technique for gene delivery. In the present work, we hypothesized that short hairpin RNA (shRNA) interference therapy targeting human Survivin gene could be transfected by the novel combination of ultrasound exposure (USE) and liposome microbubbles (LM). ShRNA vectors targeting Survivin were constructed and transfected under USE and LM conditions. The optimal transfection efficiency and cell injury were compared with those of polyethylenimine (PEI)-mediated transfection in different cancer cell lines (HeLa, HepG2, Ishikawa, MCF-7, and B16-F10). The effects of gene downregulation and cell apoptosis were further investigated. The results indicated that P + USE + LM group could significantly increase the gene expression as compared with plasmid group, plasmid + USE group, plasmid + LM group (P < 0.001). The transfection efficiency of the novel combination was nearly equal to PEI-mediated transfection in some cancer cell lines while the cell viability did not decrease markedly. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis also confirmed that Survivin mRNA and protein expression could be knocked down significantly by shRNA transfection under USE and LM condition (P < 0.001). This is the first study to verify the role of shRNA therapy in vitro with novel combination of USE and LM. We concluded that this nonviral technique would be valuable in the gene transfection of shRNA and Survivin gene downregulation would lead to apparent cell apoptosis.

HTLV-1 and apoptosis: role in cellular transformation and recent advances in therapeutic approaches

A universal cellular defense mechanism against viral invasion is the elimination of infected cells through apoptotic cell death. To counteract host defenses many viruses have evolved complex apoptosis evasion strategies. The oncogenic human retrovirus HTLV-1 is the etiological agent of adult-T-cell leukemia/lymphoma (ATLL) and the neurodegenerative disease known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The poor prognosis in HTLV-1-induced ATLL is linked to the resistance of neoplastic T cells against conventional therapies and the immuno-compromised state of patients. Nevertheless, several studies have shown that the apoptotic pathway is largely intact and can be reactivated in ATLL tumor cells to induce specific killing. A better understanding of the molecular mechanisms employed by HTLV-1 to counteract cellular death pathways remains an important challenge for future therapies and the treatment of HTLV-1-associated diseases.