Diosbulbin C, a novel active ingredient in Dioscorea bulbifera L. extract, inhibits lung cancer cell proliferation by inducing G0/G1 phase cell cycle arrest.

BACKGROUND: Despite the critical progress of non-small cell lung cancer (NSCLC) therapeutic approaches, the clinical outcomes remain considerably poor. The requirement of developing novel therapeutic interventions is still urgent. In this study, we showed for the first time that diosbulbin C, a natural diterpene lactone component extracted from traditional Chinese medicine Dioscorea bulbifera L., possesses high anticancer activity in NSCLC. METHODS: A549 and NCI-H1299 cells were used. The inhibitory effects of the diosbulbin C on NSCLC cell proliferation were evaluated using cytotoxicity, clone formation, EdU assay, and flow cytometry. Network pharmacology methods were used to explore the targets through which the diosbulbin C inhibited NSCLC cell proliferation. Molecular docking, qRT-PCR, and western blotting were used to validate the molecular targets and regulated molecules of diosbulbin C in NSCLC. RESULTS: Diosbulbin C treatment in NSCLC cells results in a remarkable reduction in cell proliferation and induces significant G0/G1 phase cell cycle arrest. AKT1, DHFR, and TYMS were identified as the potential targets of diosbulbin C. Diosbulbin C may inhibit NSCLC cell proliferation by downregulating the expression/activation of AKT, DHFR, and TYMS. In addition, diosbulbin C was predicted to exhibit high drug-likeness properties with good water solubility and intestinal absorption, highlighting its potential value in the discovery and development of anti-lung cancer drugs. CONCLUSIONS: Diosbulbin C induces cell cycle arrest and inhibits the proliferation of NSCLC cells, possibly by downregulating the expression/activation of AKT, DHFR, and TYMS.

αKG-driven RNA polymerase II transcription of cyclin D1 licenses malic enzyme 2 to promote cell-cycle progression.

Increased metabolic activity usually provides energy and nutrients for biomass synthesis and is indispensable for the progression of the cell cycle. Here, we find a role for α-ketoglutarate (αKG) generation in regulating cell-cycle gene transcription. A reduction in cellular αKG levels triggered by malic enzyme 2 (ME2) or isocitrate dehydrogenase 1 (IDH1) depletion leads to a pronounced arrest in G1 phase, while αKG supplementation promotes cell-cycle progression. Mechanistically, αKG directly binds to RNA polymerase II (RNAPII) and increases the level of RNAPII binding to the cyclin D1 gene promoter via promoting pre-initiation complex (PIC) assembly, consequently enhancing cyclin D1 transcription. Notably, αKG addition is sufficient to restore cyclin D1 expression in ME2- or IDH1-depleted cells, facilitating cell-cycle progression and proliferation in these cells. Therefore, our findings indicate a function of αKG in gene transcriptional regulation and cell-cycle control.

Antitumor mechanism of combination of Angelica gigas and Torilis japonica in LNCaP prostate cancer cells via G1 arrest and inhibition of Wnt/ß-catenin and androgen receptor signaling.

The goal of the current study is to assess the antitumor mechanism by the combination (7:3) of Angelica gigas and Torilis japonica (AT) that was found most effective through screening against prostate-specific antigen (PSA) in LNCaP prostate cancer cells. Here, AT reduced the viability and the number of colonies in androgen-dependent LNCaP cells more than in androgen independent PC3 and DU145 cells. Also, AT induced G1 phase arrest, cleaved PARP and caspase 3, activated p27 and decreased the expression of Cyclin D1, Cyclin E, cdk2 in LNCaP cells. Furthermore, AT decreased the expression of PSA and androgen receptor (AR) at mRNA and protein levels in LNCaP cells. Interestingly, AT attenuated the expression of AR, PSA and Wnt-3a and the stability of AR and PSA in LNCaP cells. Furthermore, AT reversed dihydrotestosterone (DHT)-induced upregulation of AR and PSA in LnCaP cells. Notably, AT disrupted the protein-protein interaction, nuclear translocation and fluorescent expression of ß-catenin and AR in LNCaP cells. Consistently, ß-catenin depletion enhanced the decreased expression of AR in AT treated LNCaP cells. Taken together, our findings highlight evidence that AT suppresses the proliferation of LNCaP cells via G1 arrest and inhibition of ß-catenin and AR as a potential anticancer agent.

Bergamottin a CYP3A inhibitor found in grapefruit juice inhibits prostate cancer cell growth by downregulating androgen receptor signaling and promoting G0/G1 cell cycle block and apoptosis.

Prostate cancer is the second leading cause of cancer related death in American men. Several therapies have been developed to treat advanced prostate cancer, but these therapies often have severe side effects. To improve the outcome with fewer side effects we focused on the furanocoumarin bergamottin, a natural product found in grapefruit juice and a potent CYP3A inhibitor. Our recent studies have shown that CYP3A5 inhibition can block androgen receptor (AR) signaling, critical for prostate cancer growth. We observed that bergamottin reduces prostate cancer (PC) cell growth by decreasing both total and nuclear AR (AR activation) reducing downstream AR signaling. Bergamottin's role in reducing AR activation was confirmed by confocal microscopy studies and reduction in prostate specific antigen (PSA) levels, which is a marker for prostate cancer. Further studies revealed that bergamottin promotes cell cycle block and accumulates G0/G1 cells. The cell cycle block was accompanied with reduction in cyclin D, cyclin B, CDK4, P-cdc2 (Y15) and P-wee1 (S642). We also observed that bergamottin triggers apoptosis in prostate cancer cell lines as evident by TUNEL staining and PARP cleavage. Our data suggests that bergamottin may suppress prostate cancer growth, especially in African American (AA) patients carrying wild type CYP3A5 often presenting aggressive disease.

Hydroxyphenyl Butanone Induces Cell Cycle Arrest through Inhibition of GSK3ß in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) is among the top three gastrointestinal malignancy in morbidity and mortality. The abnormal activation of Wnt/ß-catenin pathway is considered to be a key factor in the occurrence and development of CRC. Novel inhibitor discovery against key factor in WNT pathway is important for CRC treatment and prevention. METHODS: Cell proliferation was detected after hydroxyphenyl butanone treatment in human colorectal cancer HCT116, LOVO, and normal colonic epithelial NCM460 cells. Colony formation, cell invasion ability, and cell cycle were detected with and without GSK-3ß knockdown. RESULTS: Hydroxyphenyl butanone induces cycle arresting on G1-S phase of colorectal cancer cell line through GSK3ß in Wnt/ß-catenin pathway and inhibits malignant biological manifestations of cell proliferation, colony formation, and invasion. The inhibition in the high concentration group is stronger than that in the low concentration group, and the antitumor effect is different for different tumor cells. Under the same concentration of natural hydroxyphenyl butanone, the inhibition on normal colonic epithelial cells is significantly lower than that on tumor cells. The natural hydroxyphenyl butanone with medium and low concentration could promote the proliferation of normal colonic epithelial cells. CONCLUSION: This study illustrated natural hydroxyphenyl butanone as new inhibitor of GSK3ß and revealed the mechanisms underlying the inhibitory effects in colorectal cancer.

Neuroprotective effects of allocryptopine-rich alkaloid extracts against oxidative stress-induced neuronal damage.

BACKGROUND: Oxidative stress is a significant feature in the pathomechanism of neurodegenerative diseases. Thus, the search for an effective and safe novel antioxidant agent with neuroprotective properties has increased the interest in medicinal plant products as a bioactive phytochemical source. However, little is known about the potential effects of the medically important Glaucium corniculatum as a natural antioxidant. OBJECTIVE: In the present study, it was aimed to investigate the anti-oxidative, anti-apoptotic, and cell cycle regulatory mechanisms underlying the neuroprotective effects of alkaloid extracts (chloroform, methanol, and water) from G. corniculatum, which was profiled for major alkaloid/alkaloids, against H2O2-induced neuronal damage in differentiated PC12 cells. MATERIALS AND METHODS: The profiles of the alkaloid extracts were analyzed by GC-MS. The effects of the alkaloid extracts on intracellular ROS production, level of apoptotic cells, and cell cycle dysregulation were analyzed by flow cytometry; the effects on mRNA expression of apoptosis-related genes were also analyzed by qRT-PCR. RESULTS: The same alkaloid components, allocryptopine, tetrahydropalmatine, and tetrahydroberberine N-oxide were obtained in all three solvents, but the ratios of the components differed according to the solvents. Allocryptopine was determined to be the major alkaloid ingredient in the alkaloid extracts, with the highest amount of allocryptopine (497 µg/mg) being found in the chloroform alkaloid extract (CAE) (*p < 0.05). The best results were obtained from CAE, which has the highest amount of allocryptopine among alkaloid extracts in all studies. CAE suppressed intracellular ROS production (5.7-fold), percentage of apoptotic cells (3.0-fold), and cells in the sub G1 phase (6.8-fold); additionally, it increased cells in the G1 phase (1.5-fold) (**p < 0.01). CAE remarkably reduced the expressions of Bax, Caspase-9/-3 mRNA (2.4-3.5-fold) while increasing the expression of Bcl-2 mRNA (3.0-fold) (*p < 0.05). CONCLUSIONS: Our results demonstrated that alkaloid extracts from G. corniculatum, which contain allocryptopine, tetrahydropalmatine, and tetrahydroberberine N-oxide suppressed oxidative stress-induced neuronal apoptosis, possibly by suppressing the mitochondrial apoptotic pathway and regulating the cell cycle. These results are the first report that related alkaloids have played a neuroprotective role by regulating multiple mechanisms. Thus, our study indicated that these alkaloids especially allocryptopine could offer an efficient and novel strategy to explore novel drugs for neuroprotection and cognitive improvement.

Inhibition of Growth of Colon Tumors and Proliferation of HT-29 Cells by Warburgia ugandensis Extract through Mediating G0/G1 Cell Cycle Arrest, Cell Apoptosis, and Intracellular ROS Generation.

Warburgia ugandensis Sprague (W. ugandensis), widely distributed in Africa, is a traditional medicinal plant used for the treatment of various diseases including cancer. We intended to evaluate the anticolorectal cancer (CRC) activities of the crude extract from W. ugandensis (WUD) and reveal the underlying molecular mechanisms of its action. We found that WUD inhibited the proliferation of HT-29 and HCT116 cells in a time- and dose-dependent manner and induced intracellular ROS generation. The inhibitory effect of WUD on the proliferation of HT-29 and HCT116 cells could be attenuated by NAC (a ROS scavenger) in a dose-dependent manner. WUD induced G0/G1 phase arrest, down-regulated the protein expression of Cyclin D1 via ROS accumulation in HT-29 cells. In search of the molecular mechanism involved in WUD-induced Cyclin D1 down-regulation, it was found that WUD can suppress PI3K/Akt/GSK3ß signaling pathway in HT-29 cells. Next, it was found that WUD also activated apoptosis, poly-ADP ribose polymerase 1 (PARP1) cleavage and down-regulated pro-caspase 3 in HT-29 and HCT116 cells. Besides, WUD decreased the growth of colon tumors in vivo in the xenograft mouse model. We demonstrated for the first time that ROS and their modulation in the corresponding intracellular signaling could play a significant role in the potential activity of WUD against CRC cells.

Synthesis, Characterization, and Biologic Activity of New Acyl Hydrazides and 1,3,4-Oxadiazole Derivatives.

Starting from isoniazid and carboxylic acids as precursors, thirteen new hydrazides and 1,3,4-oxadiazoles of 2-(4-substituted-phenoxymethyl)-benzoic acids were synthesized and characterized by appropriate means. Their biological properties were evaluated in terms of apoptosis, cell cycle blocking, and drug metabolism gene expression on HCT-8 and HT-29 cell lines. In vitro antimicrobial tests were performed by the microplate Alamar Blue assay for the anti-mycobacterial activities and an adapted agar disk diffusion technique for other non-tubercular bacterial strains. The best antibacterial activity (anti-Mycobacterium tuberculosis effects) was proved by 9. Compounds 7, 8, and 9 determined blocking of G1 phase. Compound 7 proved to be toxic, inducing apoptosis in 54% of cells after 72 h, an effect that can be predicted by the increased expression of mRNA caspases 3 and 7 after 24 h. The influence of compounds on gene expression of enzymes implicated in drug metabolism indicates that synthesized compounds could be metabolized via other pathways than NAT2, spanning adverse effects of isoniazid. Compound 9 had the best antibacterial activity, being used as a disinfectant agent. Compounds 7, 8, and 9, seemed to have antitumor potential. Further studies on the action mechanism of these compounds on the cell cycle may bring new information regarding their biological activity.

Aerial Parts of Peucedanum chenur Have Anti-Cancer Properties through the Induction of Apoptosis and Inhibition of Invasion in Human Colorectal Cancer Cells.

Background: The Peucedanum species have many pharmacological effects due to the presence of coumarins, flavonoids, phenolic compounds, and essential fatty acids in these species. In this study, for the first time, the anticancer activity of Peucedanum chenur methanolic extract via the induction of apoptosis and inhibition of invasion in HCT-116 human colon cancer cells was investigated. Methods: P. chenur methanolic extract effect on HCT-116 cells viability and antioxidant activity were evaluated using MTT assay, 1,1-Diphenyl-2-picrylhydrazyl, and iron chelating tests, respectively. Changes in mRNA expression level in a panel of relevant genes were assessed by the quantitative real-time PCR. Also, apoptosis was assessed by cell cycle analysis and Annexin V/PI (propidium iodide) method, and the effect on cell migration was tested using scratch test. Results: P. chenur methanolic extract increased significantly the expression of BAX while decreased the expression of BCL-2, AKT1, FAK, RhoA, and matrix metalloproteinase (MMP) genes compared to the control group. BAX/BCL-2 ratio and apoptosis elevated, whereas cell migration reduced significantly. Besides, our extract showed an appropriate antioxidant activity. Conclusion: P. chenur may be introduced as a new chemopreventive agent in medicine due to its notable power in terms of induction of apoptosis and inhibition of invasion.

Isoliquiritigenin Suppressed Esophageal Squamous Carcinoma Growth by Blocking EGFR Activation and Inducing Cell Cycle Arrest.

Isoliquiritigenin (ILQ) is a natural product isolated from licorice root which has served as traditional Chinese medicine for a long time. Recently, the antitumor effects of ILQ have been widely studied in various cancers, but the role and related mechanisms of ILQ in esophageal squamous carcinoma cells (ESCC) are still poorly understood. In our studies, ILQ showed profound antitumor activities in ESCC cells. In vitro, ILQ substantially inhibited cell proliferation and anchorage-independent growth in a panel of human ESCC cells. Mechanism studies showed that EGFR signaling pathway played an important role for ILQ to exert its antitumor activity in ESCC. Exposure to isoliquiritigenin substantially decreased EGF-induced EGFR activation and its downstream Akt and ERK1/2 signaling pathway. EGFR knockdown with shRNA in ESCC cell significantly reduced the sensitivity of cancer cells to ILQ. Moreover, it was found that ILQ had a significantly inhibitory effect on AP-1 family, the protein of Jun and Fos subfamilies was substantially downregulated, and the transcriptional activity of AP-1 family was dramatically suppressed by ILQ. By reducing the expression of cyclin D1, ESCC cells were induced G0/G1 arrest, and cell division was substantially blocked. Finally, the antitumor potency of ILQ was validated in xenograft models and the tumor growth was prominently restrained by ILQ. Briefly, our study showed that ILQ, or its analogue, appeared to be a promising new therapeutic agent for ESCC management.

Cultivated Orostachys japonicus extract inhibits VEGF-induced angiogenesis via regulation of VEGFR2 signaling pathway in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Orostachys japonicus A. Berger (O. japonicus), so-called Wa-song in Korea, a traditional food and medicine that grows on mountain rocks and roof tiles. Wa-song containing various phenolic compounds have been reported as a medicinal plant for prevention of fibrosis, cancer, inflammation, and oxidative damage. AIM OF THE STUDY: The present study was designed to examine the anti-angiogenic effects of cultivated Orostachys japonicus 70% ethanol extract (CE) in vascular endothelial growth factor (VEGF)-stimulated human umbilical vein endothelial cells (HUVECs). MATERIALS AND METHODS: CE was prepared with 70% ethanol. HUVECs, rat aortic rings, and matrigel plug in mice were treated with CE (10-20 µg/mL) and VEGF (20-50 ng/mL), and the anti-angiogenic activities of CE were analyzed by SRB, wound healing, trans-well invasion, capillary-like tubule formation, rat aortas, Western blot, and matrigel plug assay. Phenolic compounds in CE were analyzed using a high-performance liquid chromatography (HPLC)-PDA system. RESULTS: Treatment of CE (10-20 µg/mL) markedly suppressed proliferation of HUVECs in the presence (from 136.5% to 112.2%) or absence of VEGF (from 100.0% to 92.1%). The proliferation inhibitory effect of CE was caused by G0/G1 cell cycle arrest, and the decrease of CDK-2, CDK-4, Cyclin D1 and Cyclin E1. Furthermore, CE treatment showed significant angiogenesis inhibitory effects on motility, invasion and micro-vessel formation of HUVECs, rat aortic rings and subcutaneous matrigels under VEGF-stimulation condition. In HUVECs, CE-induced anti-angiogenic effect was regulated by inhibition of the PI3K/AKT/mTOR, MAPK/p38, MAPK/ERK, FAK-Src, and VEGF-VEGFR2 signaling pathways. CONCLUSION: This study demonstrated that CE might be used as a potential natural substance, multi-targeted angiogenesis inhibitor, functional food material.

1,8-Cineole promotes G0/G1 cell cycle arrest and oxidative stress-induced senescence in HepG2 cells and sensitizes cells to anti-senescence drugs.

AIMS: 1,8-Cineole is a plant-derived monoterpene and a major constituent of Eucalyptus essential oil. Previously, we demonstrated that 1,8-cineole inhibited hepatocellular carcinoma (HCC) HepG2 cell growth. However, the underlying mechanisms remain unknown. Here, we evaluated the mechanisms of action of 1,8-cineole and the potential benefits of its combination with anticancer compounds harboring "anti-senescence" properties in HepG2 cells. MAIN METHODS: Cell viability was determined by the MTT assay. Cell cycle was assessed through flow cytometry (FC) and western blot (WB). Senescence was determined by the SA-ß-galactosidase assay, and apoptosis by caspase-3 activity, WB, and TUNEL. MAPKs (ERK, JNK, and p38), AMPK, and Akt/mTOR were analyzed by WB. Reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) were evaluated by FC and fluorescence microscopy. KEY FINDINGS: 1,8-Cineole inhibited cell proliferation by promoting G0/G1 arrest. While 1,8-cineole was unable to trigger apoptosis, it induced cellular senescence. 1,8-Cineole promoted ROS production, ΔΨm depolarization, AMPK, ERK, and p38 activation and mTOR inhibition. Antioxidants, like N-acetyl-L-cysteine and vitamins, prevented HepG2 cell growth inhibition and senescence induced by 1,8-cineole. Pre-incubation with 1,8-cineole sensitized HepG2 cells to the anti-senescence compounds, quercetin, simvastatin, U0126, and SB202190. Combinations of 1,8-cineole and each compound synergistically inhibited cell viability, and combined treatment with 1,8-cineole and simvastatin induced apoptosis. SIGNIFICANCE: 1,8-Cineole induces G0/G1 arrest and senescence in HepG2 cells through oxidative stress and MAPK, AMPK, and Akt/mTOR pathways, and sensitizes cells to anti-senescence drugs, suggesting that 1,8-cineole has potential as an antineoplastic and adjuvant compound in combination with anti-senescence drugs in HCC therapy.

Huganpian, a traditional chinese medicine, inhibits liver cancer growth in vitro and in vivo by inducing autophagy and cell cycle arrest.

Huganpian (HGP), a traditional chinese medicine composed of 6 herbs, possesses excellent therapeutic effects in clinical application. In this study, we aimed to elucidate the anti-tumor activity and the underlying mechanisms of HGP in liver cancer. The results of this study indicated that HGP effectively inhibited liver cancer growth in vitro and in vivo in a dose-dependent manner. Mechanistically, HGP exerted its anti-tumor effects by triggering autophagy with increased LC3Ⅱ and beclin1 levels and arrested the cell cycle on G0-G1 phase by downregulating the expressions of cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4) and cyclinE1 in vitro and in vivo. Meanwhile, HGP did not induce apoptosis significantly. Importantly, we also confirmed that there were fewer side effects of HGP on immune system. Taken together, our findings suggest for the first time that HGP may become a promising drug or adjuvant drug with a lower toxicity for liver cancer treatment in the future.

Astragalus Polysaccharide Eases G1 Phase-Correlative Bystander Effects through Mediation of TGF- ß R/MAPK/ROS Signal Pathway After Carbon Ion Irradiation in BMSCs.

Although Astragalus polysaccharide (APS) has been shown to have various pharmacological effects, there have been no studies concerning the inhibitory effects of APS on the radiation-induced bystander effects (RIBE). The aim of this study was to investigate whether APS could suppress RIBE damage by inhibiting cell growth, micronucleus (MN) formation and 53BP1 foci number increased in bone marrow mesenchymal stem cells (BMSCs), named bystander cells, as well as to explore its mechanism. In this study, APS decreased proliferation and colony rate of bystander cells by inducing cell cycle arrest at G1 phase via extrinsic and intrinsic DNA damage. Regarding mechanism, APS inhibited mitogen-activated protein kinase (MAPK) signal pathway by down-regulating the expression of the key proteins, phosphorylated JNK (p-JNK), phosphorylated ERK (p-ERK) but not phosphorylated P38 (p-P38), and down-regulating their downstream function protein and molecule, cyclooxygenase-2 (COX-2) and reactive oxygen species (ROS). Moreover, in bystander cells, APS inhibits expression of transforming growth factor ß receptor II (TGF- ß R II), a cell membrane receptor, resulting in lower ROS production and secretion via TGF- ß R-JNK/ERK-COX-2/ROS not P38 signaling. They gave a hint that the decreased RIBE damage induced by APS treatment involved TGF- ß R-JNK/ERK-COX-2/ROS down-regulation.

Supplementation of All-Trans-Retinoic Acid Below Cytotoxic Levels Promotes Adipogenesis in 3T3-L1 Cells.

Vitamin A, referred to as retinol, is an essential nutrient that affects the cell growth and differentiation including adipogenesis. Although previous studies using supraphysiological doses (over 1 µM) of all-trans-retinoic acid (atRA) demonstrated antiadipogenic activity, effects of atRA at various levels on differentiation of 3T3-L1 preadipocytes have not been extensively investigated. Our study showed that the amount of cellular triacylglycerol (TAG) and intensities of Oil-Red-O staining were decreased by supplementing atRA (1 and 10 µM) but increased by low concentrations of atRA (0.01 to 100 nM) compared with the control. Also PPARγ and FABP4 were gradually overexpressed by atRA up to 1 nM but decreased at over 1 nM concentrations. Moreover, mitotic clonal expansion (MCE) and consequential growth-arrest were analyzed as important steps in adipogenesis of 3T3-L1 cells. The 1 nM group showed more cell proliferation and thereafter a higher ratio of the G0/G1 phase on Day 2. Protein levels of S/G2-phase factors were dose dependently increased by atRA up to 1 nM on Day 1, but the factors were highly expressed in higher doses on Day 2. G0/G1 markers were higher at the higher doses of atRA on Day 1; whereas, they were highly expressed in mild or medium doses on Day 2. These data indicate that atRA controls adipogenesis with accompanied changes in cell proliferation and follow-up growth-arrest. These results indicate that atRA can function both as a negative and positive regulator of adipogenesis depending on dosages, providing a strategy for achieving proper nutritional balance for treatment of obesity.

The Molecular Mechanisms of Protective Role of Se on the G0/G1 Phase Arrest Caused by AFB1 in Broiler's Thymocytes.

This research was designed to explore the protective effects of sodium selenite on G0/G1 phase arrest induced by AFB1 in thymocytes of broilers. Two hundred eighty-eight Cobb broilers were divided into control group, + Se group (0.4 mg/kg Se), AFB1 group (0.6 mg/kg AFB1), and AFB1 + Se group (0.6 mg/kg AFB1 + 0.4 mg/kg Se). The results revealed that 0.4 mg/kg Se supplement in diets could improve the AFB1-induced histological lesions in the thymus consisting of the more vacuoles and nuclear debris in thymic cortical area. The results of flow cytometric detect showed that 0.4 mg/kg Se relieved the G0/G1 phase arrest caused by AFB1 in thymocytes. The results of transcription levels of ATM, p53, p21, p27, p15, p16, CyclinD1, CyclinE, Cdk6, Cdk2, and PCNA genes by qRT-PC, and protein expression level of PCNA by immunohistochemistry demonstrated that 0.4 mg/kg Se could reduce the adverse effects of AFB1 on these parameters. In conclusion, Se could relieve AFB1-induced G0/G1 phase arrest by p15 (or p16)-CyclinD1/Cdk6, ATM-p53-p21-CyclinE/Cdk2, p27-CyclinE/Cdk2 pathways.

Grape seeds and skin induce tumor growth inhibition via G1-phase arrest and apoptosis in mice inoculated with Ehrlich ascites carcinoma.

OBJECTIVES: Chemoprevention or intervention of cancer by means of natural dietary components has shown great promise in controlling malignancy. This study was conducted to investigate the chemopreventive effects of grape seeds (GSE) combined with grape skin (GSK) in mice that were inoculated with Ehrlich ascites carcinoma, and to elucidate the underlying mechanisms. METHODS: GSE + GSK were mixed with the standard diet and supplemented to mice 14 d before Ehrlich ascites carcinoma cell inoculation and continued throughout the experiment. Tumor growth was monitored and cell cycle progression and apoptotic effect of GSE + GSK on tumor cells were evaluated. RESULTS: GSE + GSK intake prevented tumor development in 47% of the animals. Tumor volume and weight were markedly reduced by 93.9 % and 86.3 %, respectively, compared with tumor-bearing mice that were untreated with these agents. GSE + GSK treatment caused a marked increase in the percentage of apoptotic tumor cells as evaluated by flow cytometry and confirmed by histopathologic and electron microscopy examinations. GSE + GSK also caused significant cell cycle arrest at the G1 phase, activation of caspase-3, increase in p53 and Bax expression, and decrease in B-cell lymphoma 2 expression and B-cell lymphoma 2:Bax ratio in tumor cells. Furthermore, the induction of apoptosis and cell proliferation inhibition was indicated immunohistochemically as shown by modulating p53 and Ki67 expression. CONCLUSIONS: The results of this study clearly showed that the combination of GSE and GSK represents a potent chemopreventive and anticancer agent in a mice model of Ehrlich carcinoma. The mechanisms that underlie the effects of these agents include cell cycle arrest, induction of apoptosis, and inhibition of cell proliferation. These findings suggest that GSE + GSK may represent a natural, novel, adjuvant therapeutic strategy for chemoprevention of the growth of solid tumors.

Inhibitory Effect of Damulin B from Gynostemma pentaphyllum on Human Lung Cancer Cells.

Damulin B, a dammarane-type saponin from steamed Gynostemma pentaphyllum, exhibits the strongest activity against human lung carcinoma A549 cells among the isolated active saponins. In this study, the structure-activity relationship of a series of saponin compounds was discussed. The inhibitory effect of damulin B on human lung cancer A549 and H1299 cells was investigated from apoptosis, cell cycle, and migration aspects. In vitro, human lung cancer cells were more susceptible to damulin B treatment than human normal fibroblasts. Damulin B exhibited a strong cytotoxic effect, as evidenced by the increase of apoptosis rate, reduction of mitochondrial membrane potential (MMP), generation of reactive oxygen species, and G0/G1 phase arrest. Furthermore, damulin B activated the following: both intrinsic and extrinsic apoptosis pathways along with early G1 phase arrest via the upregulation of the Bax, Bid, tBid, cleaved caspase-8, and p53 expression levels; downregulation of the procaspase-8/-9, CDK4, CDK6, and cyclin D1 expression levels; and more release of cytochrome c in the cytoplasm. In addition, antimigratory activities and suppressive effects on metastasis-related factors, such as MMP-2 and MMP-9, accompanied by the upregulation of IL-24 were revealed. Altogether, the results proved that damulin B could inhibit human lung cancer cells by inducing apoptosis, blocking the cell cycle at early G0/G1 phase and suppressing the migration. Hence, damulin B has potential therapeutic efficacy against lung cancer.

Cytotoxic and Antiproliferative Activity of Polyisoprenoids in Seventeen Mangroves Species Against WiDr Colon Cancer Cells

Background: Secondary metabolites from the group of isoprenoid compounds are widely distributed in mangrove plants. Polyisoprenoids (dolichol and polyprenol) are known to have benefits as anticancer agents. The present study was conducted to determine the cytotoxic potential of polyisoprenoids in leaves from seventeen selected mangrove species against colon cancer (WiDr) cells. Methods: Cytotoxic activity was evaluated by MTT assay in vitro using WiDr human colon cancer cells and 3T3 fibroblasts from Swiss albino mouse embryo tissue as controls. Mechanisms of action were approached by assessing apoptosis and the cell cycle using flow cytometry and fluorescence microscopy with annexin V-FITC, as well as expression of Bcl-2 and cyclin D1 by immunocytochemistry. Results: Polyisoprenoids from N. fruticans leaves demonstrated the highest anticancer activity, with an IC50 of 180.2 µg/mL, as compared to 397.7 µg/mL against 3T3 normal cells. Significant decrease in the expression of Bcl-2 and cyclin D1 was also noted, facilitating apoptosis and arrest of the cell cycle in the G0-G1 phase in WiDr cells. The present study showed for the first time that polyisoprenoids from N. fruticans exhibit concrete anticancer activity in vitro, decreasing cell proliferation and inducing apoptosis in colon cancer cells. Conclusions: Polyisoprenoids isolated from N. fruticans leaves may have promise as a source of anticancer agents.

Fucoidan Exerts Anticancer Effects Against Head and Neck Squamous Cell Carcinoma In Vitro.

Fucoidans have been reported to exert anticancer effects with simultaneous low toxicity against healthy tissue. That correlation was observed in several cancer models, however, it has never been investigated in head and neck cancer before. To magnify the efficacy of conventional therapy, the administration of agents like fucoidan could be beneficial. The aim of this study was to evaluate the anticancer effect of Fucus vesiculosus (FV) extract alone and with co-administration of cisplatin in head and neck squamous cell carcinoma (HNSCC) in vitro. MTT assay results revealed an FV-induced inhibition of proliferation in all tested cell lines (H103, FaDu, KB). Flow cytometric cell cycle analysis showed an FV-induced, dose-dependent arrest in either S/G2 phase (H103, FaDu) or G1 arrest (KB). Furthermore, a dose-dependent gain in apoptotic fraction was observed. Western blot analysis confirmed the induction of apoptosis. A significant dose-dependent increase in reactive oxygen species (ROS) production was revealed in the H103 cell line, while FaDu cells remained unresponsive. On the contrary, an HPV-positive cell line, KB, demonstrated a dose-dependent decrease in ROS synthesis. Moreover, fucoidan enhanced the response to cisplatin (synergistic effect) in all cell lines with the HPV-positive one (KB) being the most sensitive. These results have been confirmed by flow-cytometric apoptosis analysis. In conclusion, we confirmed that fucoidan exhibits anticancer properties against HNSCC, which are manifested by the induction of apoptosis, regulation of ROS production, cell cycle arrest, and inhibition of proliferation.