Victoria Palau

Chemical differences in gamma-tocotrienol including the presence of an isoprenoid side chain are responsible for differences in cytotoxic potency of gamma-tocotrienol compared to alpha-tocopherol. Alpha-tocopherol has been shown to be ineffective in prostate cancer chemoprevention in the SELECT trial; in fact, there was an increased incidence of prostate cancer in the alpha-tocopherol arm indicative of deleterious effects. Therefore, we explored the cytotoxic effects of alpha-tocopherol (AT), gamma-tocopherol (GT) and gamma-tocotrienol (GT3) in prostate cancer cell lines, PC-3 (androgen independent) and LNCaP (androgen dependent). Prostate cancer cell lines were grown in culture and treated with various concentrations and duration with the vitamin E isoforms. Cytotoxicity was determined by MTT and cell viability assays. We also explored possible molecular mechanisms to further understand differences in effects between the tocopherols and tocotrienols. GT3 showed cytotoxic effects in a dose and time-dependent manner, in both cell lines. PC-3 cells were noted to be more sensitive to growth suppression effects of GT3 than LNCaP cells. GT did not show significant cytotoxicity on cell growth at any given dose or time end point, whereas AT may promote prostate cancer cell growth. We also found that the combination of AT (40um) with increasing dose concentration of GT3 showed less pronounced cytotoxicity at 24 hours, when compared with various concentrations of GT3 alone, again suggesting a possible antagonistic role of AT. Exposure of PC-3 and LNCaP cells to increasing dose of GT3 was also examined for p-AKT, p-Erk, p-ERBB2 and phospho-c-Jun activity via Western blot at various time points. Our results show a dose dependent up regulation of pc-Jun and p-Erk in GT3 treated cells. No effects were noted on p-Akt or p-ERBB2 at the time points and concentrations studied. Some earlier studies found JNK and MAPK/Erk activation as playing a central role in the tocopherol induced apoptosis. C-Jun is downstream effector in JNK signaling pathway, activates transcription factors, which in turn modulate gene expression, to generate appropriate biological responses leading to apoptosis. In contrast to Erk recognized role in cancer cells proliferation we found Erk 1/2 up-regulation in GT3 induced apoptosis. This finding has also been reported earlier in some studies on prostate and other cancer cell lines. Our work shows that GT3 has cytotoxic effects on prostate cancer cells and induces cellular apoptosis through the modulation of phospho-c-Jun and MAPK pathways, while AT has either none or promotes prostate cancer cell growth in culture. Further studies are under way to dissect the molecular mechanisms of c-Jun and Erk activation by gamma-tocotrienol in prostate cancer cells. Citation Format: Rashid Mahboob, Victoria P. Ramsauer, Janet W. Lightner, William L. Stone, Koyamangalath Krishnan. Gamma-tocotrienol not alpha-tocopherol is cytotoxic to prostate cancer cells through modulation of phospho-c-Jun and phospho-Erk. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4351. doi:10.1158/1538-7445.AM2013-4351

Photodynamic therapy (PDT) is a cutting edge cancer treatment that is currently being researched with great interest. PDT uses an agent, commonly a porphyrin molecule, thatis activated when it is exposed to specific wavelenghths of light. Upon activation, the agent produceds a form of oxygen that causes cellular apoptosis or tissue necrosis. Some of our current results indicate that cationic porphyrins at certain wavelengtths can produce differente outcomes depending on the type of cancer. For example, while cationic porphyrins such as meso-Tetra (N-methyl-2-pyridyl) porphyine and meso-Tetra (N-methyl-3-pyridyl) porphine seem to accelerate the growth of pancreatic cancer cells (Panc 28). It doesn\u27t seem to affec the Mia Paca-w. This seems to confirm that differences in conformation and polaritiy makes a substantial difference in the outcome. Protonation enhances the excited state absorption of porphyrins probably because of changes to the expected saddle conformation. Therefore, further analysis of excitation, emission of several N-methyl substituted free base porphyrins and their respective dications would elucidate the connection between conformation, polarity and expected effect for different cancer lines

Colorectal and pancreatic cancer are leading causes of cancer related mortality, suggesting the need for further development of treatment approaches. Gnaphalin, a flavone derived from Gnaphalium gracile H. B. K. which is found in the Andean regions of South America, has shown anti-proliferative properties in solid tumors. Further investigation has shown this compound interferes with signaling conducive to proliferation and cell adhesion, inducing the cell to undergo apoptosis. The primary objective of the study was to look at key regulatory proteins in the cell survival and proliferative pathways to determine Gnaphalin’s mechanism of action. Cytotoxic activity was measured using MTT analysis on the colon cancer cell lines Caco2 and HCT-116, and on the pancreatic cancer cell lines MIA PaCa and Panc28. Apoptosis was determined by the presence of fragmented DNA via TUNEL and cleaved effector caspase 3. Finally, immunoblots were used to determine the mechanism of action using key proteins involved in both the intrinsic and extrinsic apoptotic pathways. Gnaphalin showed the highest activities in colon cancer HCT-116 and pancreatic cancer Panc 28 cells with a half maximal effective concentrations of 25.82±1.0887 and 30.07 ± 1.553 µM respectively. Gnaphalin impediment of cell viability involves the inhibition of phospho-ERK proliferation of the MAPK pathway along with phospho-FAK and c-Met, which are adhesion molecules. Gnaphalin has shown cytotoxic activity towards several colon cancer and pancreatic cancer cell lines by targeting cell proliferation and adhesion, and ultimately causing apoptosis

e13043 Background:  A goal of precision chemoprevention is to prevent or delay cancer progression by using minimally toxic agents guided by knowledge of alterations in oncogenic molecular pathways and signaling cascades. Indolent prostate cancer can benefit from chemopreventive agents by delaying growth. Vitamin E is not a single compound and refers to four tocopherols and four tocotrienols. The use of all-racemic-alpha tocopheryl acetate in preventing cancer was studied in the SELECT clinical trial. This trial found it was not chemopreventive and could promote prostate cancer. We compared the abilities of RRR-alpha-tocopherol (AT), RRR-gamma-tocopherol (GT), and gamma-tocotrienol (GT3) in preventing growth of two prostate cancer cell lines (LNCaP and PC-3) and a control prostate cell line (RWPE-1) by quantifying their effects on two signaling pathways known to be pivotal in prostate carcinogenesis, AKT and MAP Kinase (pERK). Methods:  LNCaP, PC-3, and RWPE-1 cell lines were treated with increasing concentrations of AT, GT and GT3 in DMEM, and cytotoxicity determined by MTS cell culture experiments. We determined the effect of GT3 on signaling pathways by analyzing B-actin, P-AKT and p-ERK in combination with AKT and/or MEK inhibitors via Western immunoblot and PCR analysis. Results:  Initial experiments with LNCaP and PC-3 cells showed GT3 induced the expression of pERK and p-c-JUN, inhibited cell growth and promoted apoptotic cell death. Neither AT nor GT had these effects. AKT was not activated by AT, GT or GT3. Inhibition of AKT activation via MK-2206 did not block GT3 growth inhibition in LNCaP cells. No growth inhibition was found with RWPE-1 control cells in presence of AT, GT or GT3 yet GT3 induced pERK expression. AT did not interfere with cancer growth inhibition and did not block the anticancer effects of GT3. Conclusions: GT3 induces the activation of pERK but this effect is not sufficient to account for the in vitro chemopreventive effects of this form of vitamin E. The AKT pathway is not modulated by GT3 and does not appear to be relevant to GT3 killing of PC-3 or LNCaP. Of five signaling pathways implicated in prostate carcinogenesis, we explored AKT and pERK. Future research will explore B-catenin, mTOR and PI3K.

This chapter focuses on the role of antioxidant vitamins in protecting the gastrointestinal (GI) tract from oxidative stress. A systems medicine approach is used since it alone is sufficiently comprehensive to capture the broad range of relevant complexities and interrelationships relevant to GI protection. Systems medicine utilizes and integrates the vast amount of information gained from genomics and metagenomics, as well as environmental factors, and applies this information to better patient care. A major goal of system medicine is to develop paradigms to treat or slow the progression of chronic diseases, that is, disease prevention. GI disorders are quintessential examples of chronic inflammation with its attendant oxidative stress. Genomics and metagenomics have provided great insight into the underlying molecular mechanisms for GI disorders and will eventually help define individualized diets to minimize chronic inflammation. While the role of antioxidant nutrients and micronutrients is promising, there is a need for large-scale well-designed clinical trials supported by studies using animal models.

MUC1 and MUC4 are the two membrane mucins that have been best characterized. Although they have superficially similar structures and have both been shown to provide steric protection of epithelial surfaces, recent studies have also implicated them in cellular signaling. They act by substantially different mechanisms, MUC4 as a receptor ligand and MUC1 as a docking protein for signaling molecules. MUC4 is a novel intramembrane ligand for the receptor tyrosine kinase ErbB2/HER2/Neu, triggering a specific phosphorylation of the ErbB2 in the absence of other ErbB ligands and potentiating phosphorylation and signaling through the ErbB2/ErbB3 heterodimeric receptor complex formed in the presence of neuregulin. In contrast, MUC1 has a highly conserved cytoplasmic tail, which binds beta-catenin, a key component of adherens junctions and a regulator of transcription, in a process that is tightly regulated by MUC1 phosphorylation. The specific localization of these membrane mucins to the apical surfaces of epithelial cells suggests that their signaling functions may be important as sensor mechanisms in response to invasion or damage of epithelia.

Mammary function is dependent on its three-dimensional organization, which is established and maintained by cell adhesive junctions linked through the membrane to the cell cytoskeleton. These junctions serve not only as structural elements, but also function as initiators and integrators of cell signals. In this review we discuss three types of glycoproteins whose interactions impinge on the function of mammary cell-cell junctions, cadherins, ErbB receptor tyrosine kinases and membrane mucins, as a microcosm of events regulating mammary cell behaviors. Actions of these components are integrated by the critical signaling element beta-catenin. When functioning properly, these glycoproteins, beta-catenin and associated signaling pathways mesh into a highly structured program for development and function of the gland. However, disruption or dysfunction of these glycoproteins or the signaling elements can lead to disorganization of the epithelia and ultimately to neoplasia.

Colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most common cancer in men and women. Vitamin E is a lipid soluble antioxidant that exists as eight structurally different isoforms of tocopherols and tocotrienols. Recent experimental, and molecular studies suggest that γ-tocotrienol (GT3) may be a more potent cancer-preventive form of vitamin E. 15-lipoxygenase-1 (15-LOX-1) and its product 13-S-hydroxyoctadecadienoic acid (13-S-HODE) are decreased in colon cancer cells. 15 LOX-1 is considered a tumor suppressor gene in colon carcinogenesis. Non-steroidal anti-inflammatory drug (NSAID)-induced 15-LOX-1 expression is critical to aspirin and NSAID-induced apoptosis in colorectal cancer cells. HCT-116 is a microsatellite-instability (MSI) colon cancer cell line. MSI is a marker of chemo-resistance but is associated with improved survival as compared to microsatellite-stable (MSS) colon cancers. The effects of GT3 on cytotoxicity and 15 LOX-1 expression was studied on the human colon cancer cell line HCT-116. HCT-116 colon cancer cell lines were cultured in DMEM media and dosed with increasing concentrations of GT3 (20µM-50µM). Cytotoxicity of the drugs was studied using Cell Titer Glo and MTS assays 24 hours after dosing. Cells were then plated in 6-well plates and grown for 24 hours. Cells were then dosed with 2 mL of GT3 at 20 uM at the respective time periods (2h, 4h, 6h, 12h, 16h, 24h) and lysates were harvested. Gel electrophoresis was run according to BCA protein assay from the time-dependent lysates and blots were tagged with a rabbit 15-lox antibody. Ongoing experiments include RNA PCR. RNA is being isolated at 2, 4, 6 and 12 hours. The RNA as reversed transcribed using a 15 lox 1 primer and that cDNA is being quantified using Quantitative PCR. GT3 induced cytotoxicity in MTS assay and Cell Titer Glo assay when added to HCT-116 cell line. 15 LOX 1 protein expression was found to be up-regulated in the colon cancer cell line HCT-116 when GT3 was added at 12h, 16h and 24h with the maximum expression at 16 hours. Chemotherapeutic drugs can have significant side effects. Understanding the role of GT3 on colon cancer cell lines could lead to the development of novel drugs to supplement current chemotherapy regimens and allow for lower doses of chemotherapeutic agents. Modulation of 15-LOX-1 suggests that GT3 may induce apoptosis through induction of the lipoxygenase pathway. Further experiments are under way to study the mechanism of action of GT3 on the 15 LOX-1 pathway. Since HCT-116 is a MSI- colon cancer cell line, effects of GT3 on MSS- colon cancer cell lines will also be studied

ABSTRACT Prostate cancer is the most common noncutaneous malignancy in men. It is an excellent target for primary prevention. Vitamin E trials conducted for prevention of prostate cancer have had conflicting results with a lower incidence of prostate cancer in the ATBC trial and a higher incidence in the vitamin E arm of the SELECT trial. Most of the clinical trials with vitamin E have been limited to the alpha-tocopherol isoform alone. An increasing body of evidence suggests, however, that the gamma- and delta-isoforms of tocopherol and tocotrienols are more promising with regard to cancer prevention. This review tries to justify our assertion that the gamma- and delta-isoforms of tocopherol and tocotrienol might be superior as prostate cancer preventers.

Abstract: Pancreatic cancer is the fifth leading cause of cancer death in the United States. Alternate strategies to treat and prevent this cancer are urgently required. In this regard, novel therapeutic agents that can inhibit signaling pathways implicated in the proliferation and survival of pancreatic cancer cells are of immense interest. Tocotrienols are members of the Vitamin E family but, unlike tocopherols, possess an unsaturated isoprenoid side-chain that confers superior anti-cancer properties. The ability of tocotrienols to selectively inhibit the HMG CoA reductase pathway through post-translational degradation of HMG CoA reductase and to suppress the activity of transcription factor NFκβ could be the basis for some of these properties. Data: Our studies indicate that γ- and Δ-tocotrienol have potent anti-proliferative activity in pancreatic cancer cells (Panc-28, MIA-PACA-2 and BXPC-3). Indeed both tocotrienols induced cell death (> 50%) by the MTT cell viability assay in all three pancreatic cancer cell lines. We also examined the effects of the tocotrienols on the Akt and the Ras/Raf/MEK/ERK signaling pathways by Western blotting analysis. γ- and Δ-Tocotrienol treatment of cells reduced the activation of ERK MAP kinase and that of its downstream mediator RSK (ribosomal protein S6k) in addition to suppressing the activation of protein kinase, Akt. Suppression of activation of Akt by gamma-tocotrienol led to downstream upregulation of Fox-03 and GSK-3b. These effects were mediated by the downregulation of Her2/ErbB2 at the messenger level. Tocotrienols but not tocopherols were able to induce the observed effects. Conclusion: Our results suggest that the tocotrienol isoforms of vitamin E can induce apoptosis in pancreatic cancer cells through the suppression of vital cell survival and proliferative signaling pathways such as those mediated by the PI3/Akt and ERK/MAP kinases via downregulation of Her2/ErbB2 expression. The molecular components for this mechanism are not completely elucidated and needs further investigation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4490. doi:10.1158/1538-7445.AM2011-4490

Previous results in our laboratory suggest that the (CG) 4 segments whether present in a right-handed or a left-handed conformation form distinctive junctions with adjacent random sequences. These junctions and their associated sequences have unique structural and thermodynamic properties that may be recognized by DNA-binding molecules. This study probes these sequences by using the following small ligands: actinomycin D, 1,4-bis(((di(aminoethyl)amino)ethyl)amino)anthracene-9,10-dione, ametantrone, and tris(phenanthroline)ruthenium (II). These ligands may recognize the distinctive features associated to the (CG)4 segment and its junctions and thus interact preferentially near these sequences. Restriction enzyme inhibition assays were used to determine whether or not binding interactions took place, and to approximate locations of these interactions. These binding studies are first carried out using two small synthetic oligomers BZ-III and BZ-IV. The (5meCG)4 segment present in BZ-III adopts the Z-conformation in the presence of 50 m M Co(NH3)63+. In BZ-IV, the unmethylated (CG)4 segment changes to a non-B conformation in the presence of 50 m M Co(NH3)63+. BZ-IV, containing the (CG)4 segment, was inserted into a clone plasmid then digested with the restriction enzyme Hinf I to produce a larger fragment that contains the (CG)4 segment. The results obtained on the small oligomers and on the larger fragment for restriction enzyme Mbo I indicate that 1,4-bis(((di(aminoethyl)amino)ethyl)amino)anthracene-9,10-dione binds more efficiently at or near the (CG)4 segment. Restriction enzymes EcoRV, Sac I and Not I with cleavage sites upstream and downstream of the (CG)4 insert were used to further localize binding interactions in the vicinity of the (CG)4 insert. RNA polymerase activity was studied in a plasmid which contained the (CG)4 insert downstream from the promoter sites of SP6 and T7 RNA polymerases. Activities of these two polymerases were studied in the presence of each one of the ligands used throughout the study. Only actinomycin D and spider, which bind at or near the (CG)4 segment, alter the activities of SP6 and T7 RNA polymerases. Surprisingly, enhancement of polymerase activity was observed in the presence of very low concentrations of actinomycin D. These results suggest that the conformational features of (CG) segments may serve in regulatory functions of DNA. ^

Introduction Statins and tocotrienols modulate the cholesterol biosynthesis pathway by inhibiting the 3-hydroxy-3- methylglutaryl coenzyme A (HMG-CoA) reductase. Tocotrienols modulate HMG-CoA reductase by post-transcriptional downregulation. In addition, tocotrienols contain a farnesol moiety in its side-chain that triggers degradation of HMG-CoA reductase. These effects lead to suppression of cell proliferation, cell cycle arrest, and apoptosis. Several studies have shown that statins have suppressive effects in in vitro experiments on acute myelocytic leukemia cell lines. Since both statins and gamma-tocotrienol are associated with decreased cholesterol biosynthesis, we hypothesized that if the cytotoxicity of these drugs on cancer cells is related to impaired biosynthesis of cholesterol, combination of them could synergize in cytotoxicity on leukemic cells. Materials and Methods K-562 and HL-60 leukemia cells were grown in…

Multiple Myeloma is cancer of plasma cells and is known to be highly invasive. Multiple Myeloma makes up 1% of cancer diagnosis in western countries and affects men more predominantly than women. The American Cancer Association estimates that 32,110 new cases will be diagnosed in the United States in 2019. Lenalidomide is one of the main therapies used for multiple myeloma patients, but it has toxic side effects such as thrombocytopenia, neutropenia, and anemia. The purpose of the study is to investigate new cytotoxic agents for the treatment of multiple myeloma. In addition to lenalidomide alone, this study examined the effects of doxycycline alone and in combination with lenalidomide. Lenalidomide cell cultures were treated at concentrations from 0.5μM to 10μM on untreated 24 well plates and doxycycline concentration ranging from 10μM-80μM. Following incubation, cell viability was tested using MTT assay and the samples were analyzed using spectrophotometry. When compared to lenalidomide, doxycycline monotherapy showed a greater decrease in overall cell viability in preliminary results. Our results show that there is benefit of using 10μM of Doxycycline at higher concentration of 5μM and 10μM of lenalidomide. The potential decrease in the concentration of lenalidomide used by adding doxycycline, may reduce the toxic side effects of lenalidomide. Further studies are necessary to confirm these preliminary results and investigate the mechanism of action in order to determine optimal combinations of these drugs

Abstract Oxidative stress is a documented factor in the pathogenesis of inflammation and cancer. Vitamin E with its antioxidant properties holds promise for use in clinical practice. There are two main forms of vitamin E, tocopherols and tocotrienols. Palm oil contains almost 70% of tocotrienols. Tocotrienols exerts its antiproliferative activity against malignant cells but not on normal cells. Tocotrienols play an important role in counteracting cellular inflammatory response secondary to oxidative stress, thus exerting an anticancer property. Tocotrienols mediate function of NF-kappa B, STAT3 (signal transduction and activators), and COX-2. In addition to its role as an antioxidant and anti-inflammatory agent, tocotrienols also mediate multiple cell cycle pathways. More work needs to be done on animal models and in genetic models of pancreatic cancer to gather more data to eventually consider phase III clinical trial in human subjects.

Additional Hydroxyl group on CT6 (3,4-dihydroxy-5,7-dimethoxyflavone), a flavone extracted from Chromolaena Tacotana potentially confers additional activity against pancreatic cancer as compared to CT7 (4-hydroxy-5,7-dimethoxyflavone) Parker Wade1, Miranda Green1, April Weaver1, Omri Coke1, Ruben D. Torrenegra2, and Victoria Palau1 1Department of Pharmaceutical Sciences, College of Pharmacy, East Tennessee State University, Johnson City, TN. 2Department of Chemistry, Universidad de Ciencias Aplicadas y Ambientales, Bogota, Colombia and Pancreatic cancer is one of the deadliest types of cancers, with a mortality rate of about 95%. This high mortality rate signifies there is a need for further research into finding treatment options for those affected by pancreatic cancer. Recent studies have found cytotoxic effects on cancerous cells elicited from compounds, such as flavones, in plants indigenous to Western South America, specifically Colombia. The flavones 3,4-dihydroxy-5,7-dimethoxyflavone (CT6) and 4-hydroxy-5,7-dimethoxyflavone (CT7) were isolated from Chromolaena Tacotana, member of the asteraceae family. The molecular structures of the flavones differ only by an additional hydroxyl group on CT6. Both of these compounds were tested on MIA PaCa2 and Panc28 pancreatic cancer cells at concentrations ranging from 5μM to 80μM. Cell viability after dosing of CT6 and CT7 was determined using MTT and spectrophotometry analysis. MIA PaCa2 is more poorly differentiated than Panc28. CT6 conferred greater activity on both cell lines compared to CT7. Percent cell viability of the Panc28 cell line reached a low of 35.55% (p=0.0001) with CT6, compared to 84.25% (p=0.0275) with CT7. Percent cell viability of the MIA PaCa2 cell line reached a low of 46.72% (p=0.000001)with CT6. However, CT7 showed no significant difference, with percent cell viability reaching 103.73% (p=0.5605) when compared to the control for this cell line. While CT6 exerted cytotoxic activity on both Panc28 and MIA PaCa2, CT6 had significantly more cytotoxic activity on Panc28, which could be related to the greater differentiation status of this cell line. More in depth studies will need to be conducted to determine the exact reasons for greater activity of CT6 on Panc28 cells. This could be due to the compound’s target, mitochondrial activity of the cell lines, and the minor structural differences between the two compounds

Introduction: Breast cancer is the most frequently diagnosed cancer found in women across the world, with an estimated 2.3 million new cases occurring in 2020. Additionally, over 684,000 deaths annually are attributed to breast cancer across the globe, making it the most common cause of cancer-related death in women. Further, treatment of breast cancer relies heavily on whether or not the cancer cells express estrogen, progesterone, and HER 2 receptors and this expression profile is often related to how quickly the cells grow and spread. In the United States, breast cancer cells that are hormone receptor positive and HER-2 negative make up about 73% of breast cancer cases, and cells that do not express any receptor and are known as triple negative, make up around 12% of cases (American Cancer Society, 2019). With that being said, CT1 and CT3 are novel compounds that have a cytotoxic effect on cell lines representing up to 85% of all breast cancer subtypes in the United States. Methods: The leaves of Chromolaena tacotana that contains the flavonoids CT1 and CT3 were dried and placed in a soxhlet extractor using dichloromethane (CH2Cl2) to extract the chlorophyll. The flavonoids were extracted using a column chromatography eluted with trichloromethane (CHCl3), a 1:1 dilution of CHCl3:methanol and methanol, followed by isolation and purification of the compounds. Human breast cancer cell lines MCF7, MDA-MB-231, and SKBr3 were treated with CT1 and CT3 at concentrations of 5, 10, 20, 40 and 80 µM, followed by incubation for 24 hours. To assess cell viability an MTT assay was conducted by adding a 5-diphenyl-tetrazolium bromide reagent. The purple-colored formazan crystals were solubilized with acidified isopropanol, then analyzed by spectrophotometry. Results: CT1 appeared to have the most cytotoxic effects compared to CT3 on MCF7. The opposite effect was observed for SKBr3 with CT3 showing the most effects as compared to CT1. No differential effect was observed on MDA-MB-231 since both CT1 and CT3 showed similar inhibition of cell viability. Conclusions: The results from the different breast cancer cell lines SKBr3, MCF7, and MDA-MB-231 vary based on how they responded to CT1 and CT3. CT3 was more effective on SKBr3 than CT1. CT1 was more effective on MCF7 than CT3. For MDA-MB-231, both CT1 and CT3 showed similar significant cytotoxic effects. The antiproliferative effects of CT1 and CT3 appear to be concentration dependent on all cells studied. In view of the results from MDA-MB-231 triple negative breast cancer cell line, the cytotoxic effect of the flavonoids is not dependent on the presence of estrogen, progesterone, or HER2 receptors on breast cancer cells. Further studies on the mechanism of action are necessary to elucidate the molecular targets of CT1 and CT3

Over 5000 flavonoids have been identified so far and many of these are known to have antineoplastic properties. The relationships between the targeting activities by these compounds on cancer cells and the specific features that determine their molecular structures are not completely elucidated. Here we report the differential cytotoxic effects of two unsubstituted ring B flavonoids that differ solely in the presence of a C2, C3 double bond in ring C, on human cancer cells of the lung (A549), pancreas (MIA PaCa-2, Panc28), colon (HCT 116, CaCo-2), Liver (HepG2), and breast (SKBr3). These compounds were extracted from Chromolaena leivensis (Hieron) a plant belonging to the genus Chromolaena reputed to have antitumor activities. 3, 5 dihydroxy-7-methoxyflavone induce apoptosis in cancer cells of the lung A549, pancreas MIA PaCa-2 and Panc28, and colon HCT116, but not on Caco-2; whereas 3,5 dihydroxy-7-methoxyflavanone display proliferative effects in A549, Panc 28, MIA PaCa, and HCT11...

Ethanol and n-hexane extracts obtained from the leaves and inflorescences of Gnaphalium gracile, were tested at different concentrations to evaluate their antineoplastic activities on pancreatic, colon, and prostate cancer cell lines by examining mitochondrial function. The polar extracts of both, leaves and inflorescences which contain gnaphalin, quercetin, and 3-methoxy quercetin, exhibited cytotoxicity against every cell line tested with EC50 values ranging between 20.23±1.185 μg/mL and 70.71±1.1419 μg/mL. The most remarkable values were observed in pancreatic cancer Panc 28 and androgen-dependent prostate LnCaP cells, with EC50 values of 20.23±1.185 and ˂25μg/mL, and androgen-independent prostate cancer PC-3, colon HCT-116 and pancreatic MIA PaCa cells with values ranging between 28.84±1.1766 and 34.41±1.057 μg/mL. The non-polar extract derived from leaves demonstrated significant cytotoxicity towards colon cancer HCT-116 cells, with an EC50 of 39.46±1.0617 μg/mL. However, the n...

Targeting the mutant BRAF and immunotherapy are new approaches to the treatment of metastatic malignant melanoma that has significantly improved survival but is associated with significant toxicity and cost. Potent and specific BRAF inhibitors like vemurafenib and dabrafenib are superior to chemotherapy in treatment of BRAF mutant melanomas which represent nearly 50% of all melanomas. A less toxic approach to treatment of malignant melanoma is hence appealing. Delta-tocotrienol (DT3), an unsaturated vitamin E isoform, and simvastatin, an HMG-CoA reductase inhibitor have been shown to have anti-neoplastic properties. We studied the effects of these chemicals in both BRAF-mutated SK-MEL-28 and BRAF-wild type SK-MEL-2 melanoma cells. MTS assays were used to analyze cytotoxicity. SK-MEL-28 and SK-MEL-2 cells were cultured in MEM media containing 10% serum and plated in 96-well culture plates for 48 hours then treated with DT3 (0-80 µM), simvastatin (0-10 µM), or a combination and dosed again at 72 hours. SK-MEL-28 and SK-MEL-2 cells were grown in 60 mm plates and treated with DT3 at concentrations of 30 µM, simvastatin at concentrations of 10 µM and combination of DT3 and simvastatin at concentrations of 10 µM and 2 µM. Cell were lysed with RIPPA buffer with protease and phosphatase inhibitor after 6 hours of treatment. Protein concentration of cell lysates was measured spectrophotometrically (GLO Max Multi+, Promega), using a BCA protein assay kit. The samples were run in SDS PAGE and blotted onto nitrocellulose membranes. Membranes were incubated with antibodies against Hsp 70 (Enzo Life Sciences, Farmingdale, NY), Hsp 90 (Santa Cruz, Dallas, TX), pS6 and pERK (Cell Signaling, Danvers, MA) and pAKT. Using MTS assay, we found that DT3 (IC50 75.2 μM) and simvastatin (IC50 8.3μM) have cytotoxic effects on melanoma cell line SK-MEL-2, but not on the SK-MEL-28 cells DT3 and simvastatin at the concentrations studied (10-80 μM DT3) and (0.625- 10 μM simvastatin). Further studies determined that simvastatin decreased expression of pS6, pERK on SK-MEL-2 and not DT3. However, these effects are different in SK-MEL-28 cells where there is only decrease in expression of pS6; treated SK-MEL-2 cells also show over-expression of Hsp70 suggestive of a rescue effect leading to lesser cytotoxic activity. The selective cytotoxicity observed in wild type BRAF melanoma cell lines by DT3 and simvastatin warrants further research into the potential therapeutic use of these drugs. A differential cytotoxicity is shown by DT3 and simvastatin in malignant melanoma cells with selective more potency in wild type BRAF melanoma compared to mutant BRAF melanoma cells. Further studies will be undertaken to dissect the mechanistic basis of this differential response

Targeting the mutant BRAF protein is an accepted approach to the treatment of metastatic melanoma. Potent and specific BRAF inhibitors like vemurafenib and dabrafenib are superior to chemotherapy in treatment of BRAF mutant melanomas which represent nearly 50% of all melanomas. Previous studies have shown that certain isoforms of vitamin E and statins can have synergistic anti-cancer activity. We determined whether a combination of delta-tocotrienol (DT3), an unsaturated vitamin E isoform, and simvastatin, an HMG-CoA reductase inhibitor, can exert an anti-neoplastic activity on BRAF-mutated SK-MEL-28 and BRAF-wild type SK-MEL-2 melanoma cell lines and whether a differential effect would be evident. MTS assays were used to analyze cytotoxicity. SK-MEL-28 and SK-MEL-2 cells were cultured in MEM media containing 10% serum and plated in 96-well culture plates for 24 hours then treated with DT3 (0-40 μM), simvastatin (0-5 μM), or a combination and dosed again at 48 hours. SK-MEL-28 and SK-MEL-2 cells grown in 60 mm plates and were treated with DT3 at concentrations of 40, 30, 20 μM, simvastatin at a concentrations of 20, 10, 5 μM or dissolution vehicle as a control for 6 h. Protein concentration of cell lysates was measured spectrophotometrically (GLO Max Multi+, Promega), using a BCA protein assay kit. The samples were run in SDS PAGE and blotted onto nitrocellulose membranes. Membranes were incubated with antibodies against Hsp 70 (Enzo Life Sciences, Farmingdale, NY), Hsp 90 (Santa Cruz, Dallas, TX), pS6 and pBAD (Cell Signaling, Danvers, MA). Using MTS assay, we found that DT3 (IC50 38.8 μM) and simvastatin (IC50 22.7μM) have cytotoxic effects on melanoma cell line SK-MEL-28, but on the SK-MEL-2 cells DT3 does not have an effect at the concentrations studied (10-40 μM DT3) yet simvastatin (IC50 16.9 μM) does have cytotoxicity. Further studies determined that combinations of these drugs display a synergistic effect on SK-MEL-28 by inhibition of pS6 and pBAD and subsequent apoptosis. However, these effects are not observed in SK-MEL-2 cells; treated SK-MEL-2 cells show over-expression of Hsp70 and Hsp90 suggestive of a rescue effect leading to lesser cytotoxic activity. The selective cytotoxicity observed in BRAF-mutated cells and not in wild type BRAF melanoma cell lines by both DT3 and simvastatin warrants further research into the potential therapeutic use of these combinations. This observation has added importance in the light of recent findings that show the acquisition of BRAF mutation is an early event in melanogenesis and hence these compounds may have a key role in chemoprevention approaches to melanoma. Citation Format: Kelley Cross, Victoria Palau, Marianne Brannon, Janet Lightner, Megan Dycus, William Stone, Koyamangalath Krishnan. Delta-tocotrienol and simvastatin induce cytotoxicity and synergy in BRAF mutant SK-MEL-28 but not in wild type BRAF SK-MEL-2 melanoma cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3568.

INTRODUCTION. Muc4(SMC) is a cell surface glycoprotein composed of two non-covalently bound subunits: an O-glycosylated mucin subunit, ASGP-1, and a mainly N-glycosylated transmembrane subunit ASGP-2 that anchors the molecule to the plasma membrane. The latter serves as an intramembrane ligand for the receptor tyrosine kinase ErbB2 via an EGF-like domain. This interaction occurs shortly after synthesis of the proteins, and yields a stable complex. The ErbB2 present in the complex appears activated, but it displays a limited state of phosphorylation. The Muc4 ErbB2 complex has been demonstrated on ascites tumors, normal lactating mammary gland, isolated rat mammary epithelial cells, Muc4-transfected MCF-7 breast cancer cells, and insect cells infected via the baculovirus expression system. Muc4 is constutively expressed in many tissues, where it serves mainly a protective function. It is tightly regulated in the mammary gland and the female reproductive tract. In some adenocarcinomas...

e13043 Background:  A goal of precision chemoprevention is to prevent or delay cancer progression by using minimally toxic agents guided by knowledge of alterations in oncogenic molecular pathways and signaling cascades. Indolent prostate cancer can benefit from chemopreventive agents by delaying growth. Vitamin E is not a single compound and refers to four tocopherols and four tocotrienols. The use of all-racemic-alpha tocopheryl acetate in preventing cancer was studied in the SELECT clinical trial. This trial found it was not chemopreventive and could promote prostate cancer. We compared the abilities of RRR-alpha-tocopherol (AT), RRR-gamma-tocopherol (GT), and gamma-tocotrienol (GT3) in preventing growth of two prostate cancer cell lines (LNCaP and PC-3) and a control prostate cell line (RWPE-1) by quantifying their effects on two signaling pathways known to be pivotal in prostate carcinogenesis, AKT and MAP Kinase (pERK). Methods:  LNCaP, PC-3, and RWPE-1 cell lines were treated...

Antineoplastic activity has been previously shown for two isomeric flavones, 5,7-dihydroxy-3,6,8-trimethoxy flavone (flavone A) and 3,5-dihydroxy-6,7,8-trimethoxy flavone (flavone B), against colon cancer cell lines (Thomas et al. in PLoS ONE 7:e39806, 5). Here, we present modified methods for the extraction and quantification of flavones A and B in rat colon tissue after intravenous dosing via high performance liquid chromatography, from the originally described procedure for extraction and quantification in rat plasma (Whitted et al. in J Chromatogr B Analyt Technol Biomed Life Sci 1001:150-155, 7). Modifications included tissue homogenization (1 g tissue: 2 mL water), filtration of the supernatant with a PVDF membrane, and the use of only one calibration curve to determine the concentration of each flavone in colon tissue. Good separation was achieved and representative equations were linear with r (2)  ≥ 0.99 for both flavones. Precision and accuracy for flavone A ranged from 0....

The mevalonate pathway plays an important role in cancer biology and has been targeted with farnesyl transferase inhibitors, although their efficacy is limited due to significant adverse effects. Statins and bisphosphonates inhibit the mevalonate pathway at different steps, thus having negative effects at various levels on cancer cells. A combination of these drugs may result in an amplified cytotoxic effect and allow for use of significantly lower doses of the drugs involved. Statins inhibit the mevalonate pathway at 3-hydroxy-3-methylglutaryl coenzyme A reductase and bisphosphonates at farnesyl pyrophosphate synthase. Our results show that low-dose combinations of simvastatin and alendronate have a synergistic cytotoxic effect on androgen-independent prostate cancer PC-3 cells, but not on androgen-dependent LNCaP or DU 145 prostate cancer cells. These two drugs cause a sequential blockade of the mevalonate pathway and significantly affect survival and apoptotic pathways by down-re...

Observing alteration of restriction enzyme activity has been employed frequently to determine the sequence specificity of the binding of many types of molecules to DNAs. Generally, these studies employed restriction enzymes which cut the target DNA several times. The effects of binding to sequences flanking the restriction enzyme cleavage sites may have been obscured. In this study, we report on restriction enzyme activity assays of the binding of the intercalators actinomycin D, ametantrone and ethidium, the groove binder netropsin, and the covalent binding cisplatin to a mixture of supercoiled and relaxed phiX 174 RF DNA using restriction enzymes which cleave this DNA once or twice. Sequence selectivities and topological selectivities were observed for these ligands. In some cases restriction enzymes not containing the reported preferred binding sites had altered activities, suggesting binding to flanking sequences affects activity in neighboring DNA sequences.

Over the last two decades an enormous amount of scientific effort has been devoted to studying the relationship between vitamin E and prostate cancer. This effort is well justified since prostate cancer remains the most common cancer in American men after skin cancer and is the second leading cause of cancer deaths: over 220,000 men will develop prostate each year (U.S. Cancer Statistics Working Group 2011). Nevertheless, large scale, well designed clinical intervention studies have not shown that alpha-tocopherol prevents prostate cancer or cancer in general (Lippman et al. 2008, Ju et al. 2010a, Wada 2011a). Alpha-tocopherol is the primary form of vitamin E in the plasma of fasting subjects and the primary form of vitamin E in most vitamin supplements. Gamma-tocopherol is, however, the primary dietary form of vitamin E. Vitamin E is a term that refers to at least eight different compounds that fall into two general categories, tocopherols and tocotrienols. Tocotrienols are normall...