Lavanya Reddivari

Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

BackgroundObesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4, 5,-trihydroxystilbene), a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established.MethodsWe investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity) and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis.ResultsResveratrol (100-150 μM) exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G0/G1-S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway.ConclusionsFor the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and activation of p53, suggesting its potential role as a chemotherapeutic agent.

Cooking methods and storage treatments of potato: effects on carotenoids, antioxidant activity, and phenolics.

The influence of genotype, cooking method, and storage treatments on potato compounds associated with improved human health was analyzed. Antioxidant activity (AA), total phenolics (TP), and total carotenoids (xanthophyll carotenoids, CAR) were determined in eight genotypes using 2,2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu reagent, and spectrophotometric absorbance, respectively. Individual phenolic and carotenoid composition was analyzed using high performance liquid chromatography (HPLC) in three genotypes of potato. Samples were subjected to a combination of storage conditions for approximately 4xa0months (non-stored or stored for 110xa0days at either 4°C, 4°C with an additional 10xa0days of reconditioning at 20°C, or 20°C storage) and cooking methods (baking, boiling, frying, or microwaving); an uncooked sample was used as a control. The non-stored samples had lower amounts of CAR, AA, and TP along with the individual compounds compared to the various storage regimes, while the recondition storage treatment produced equal or higher levels of TP and individual phenolics than any other storage regime. No cooking and boiling resulted in significantly lower AA and TP, as compared to baking, frying and/or microwaving. Baking, frying and/or microwaving also increased the levels of chlorogenic acid, caffeic acid, (-) epicatechin, p-coumaric acid and vanillic acid, but decreased quercetin dihydrate when compared to uncooked samples. Most health promoting compounds were enhanced by one or both postharvest processing parameters (storage and cooking); however, t-cinnamic acid, and lutein were not affected.ResumenSe analizó la influencia del genotipo, del método de cocinado y de tratamientos en el almacén, sobre los compuestos de papa asociados con el mejoramiento de la salud humana. Se determinó la actividad antioxidante (AA), fenoles totales (TP), y carotenoides totales (carotenoides xantofílicos, CAR), en ocho genotipos, usando 2,2-difenil-1-picrilhidrazilo (DPPH), el reactivo de Folin-Ciocalteau, y la absorbancia espectrofotométrica, respectivamente. Se analizaron los fenoles individuales y la composición de los carotenoides usando cromatografía de líquidos de alta resolución (HPLC) en tres genotipos de papa. Las muestras estuvieron sujetas a una combinación de condiciones de almacenamiento por aproximadamente cuatro meses (sin almacenar, o almacenadas por 110 días ya fuera a 4°C, a 4°C con diez días adicionales de reacondicionamiento a 20°C, o a 20°C en el almacén), y métodos de cocinado (horneadas, hervidas, fritas, o en el horno de microondas); se usó una muestra sin cocinar como testigo. Las muestras sin almacenar tuvieron las cantidades más bajas de CAR, AA, y TP, junto con los compuestos individuales comparados a los diversos regímenes de almacenamiento, mientras que el tratamiento de reacondicionamiento en el almacén produjo niveles iguales o mayores de TP y de fenoles individuales que cualquier otro régimen de almacenamiento. Sin cocinar y hervidas resultaron en contenido más bajo de AA y TP, comparadas con el horneado, fritas, y/o en el horno de microondas. Horneadas, fritas y en microondas también aumentaron los niveles de ácido clorogénico, ácido caféico, (-) epicatequina, ácido p-coumárico, y ácido vainillico, pero disminuyó la quercetina dihidratada cuando se les comparó con las muestras sin cocinar. Se incrementaron la mayoría de los compuestos que promueven la salud por uno o los dos parámetros de procesamiento postcosecha (almacenamiento y cocinado); no obstante, no se afectaron el ácido t-cinnamico y la luteína.

The Bioactive Compounds α-Chaconine and Gallic Acid in Potato Extracts Decrease Survival and Induce Apoptosis in LNCaP and PC3 Prostate Cancer Cells

We recently reported that colored potato extracts and an anthocyanin rich fraction suppressed lymph-node carcinoma of the prostate (LNCaP) and prostate cancer-3 (PC-3) prostate cancer cell proliferation and induced apoptosis via caspase-dependent and caspase-independent pathways. Chlorogenic acid, caffeic acid, gallic acid, catechin, malvidin, and glycoalkaloids (α-chaconine and solanine) have now been identified as the major bioactive components of potato, and their effects on LNCaP and PC-3 cell proliferation and apoptosis have been investigated. α-chaconine (5 μg/ml) and gallic acid (15 μg/ml) exhibited potent antiproliferative properties and increased cyclin-dependent kinase inhibitor p27 levels in both cell lines. Both α-chaconine and gallic acid induced poly [adenosine diphosphate (ADP)] ribose polymerase cleavage and caspase-dependent apoptosis in LNCaP cells; however, caspase-independent apoptosis through nuclear translocation of endonuclease G was observed in both LNCaP and PC-3 cells. α-chaconine and gallic acid activated c-Jun N-terminal protein kinase (JNK), and this response played a major role in induction of caspase-dependent apoptosis in LNCaP cells; whereas modulation of JNK and mitogen-activated protein kinase did not affect α-chaconine- and gallic acid-induced caspase-independent apoptosis. These results suggest that apoptosis induced by whole potato extracts in prostate cancer cell lines may be in part due to α-chaconine and gallic acid.

Resveratrol suppresses human colon cancer cell proliferation and induces apoptosis via targeting the pentose phosphate and the talin-FAK signaling pathways-A proteomic approach

BackgroundWe and others have previously reported that resveratrol (RSV) suppresses colon cancer cell proliferation and elevates apoptosis in vitro and/or in vivo, however molecular mechanisms are not fully elucidated. Particularly, little information is available on RSVs effects on metabolic pathways and the cell-extra cellular matrix (ECM) communication that are critical for cancer cell growth. To identify important targets of RSV, we analyzed whole protein fractions from HT-29 advanced human colon cancer cell line treated with solvent control, IGF-1 (10 nM) and RSV (150 μM) using LC/MS/MS-Mud PIT (Multidimensional Protein Identification Technology).ResultsPentose phosphate pathway (PPP), a vital metabolic pathway for cell cycle progression, was elevated and suppressed by IGF-1 and RSV, respectively in the HT-29 cell line. Enzymatic assays confirmed RSV suppression of glucose-6 phosphate dehydrogenase (rate limiting) and transketolase, key enzymes of the PPP. RSV (150 μM) suppressed, whereas IGF-1 (10 nM) elevated focal adhesion complex (FAC) proteins, talin and pFAK, critical for the cell-ECM communication. Western blotting analyses confirmed the suppression or elevation of these proteins in HT-29 cancer cells treated with RSV or IGF-1, respectively.ConclusionsProteomic analysis enabled us to establish PPP and the talin-pFAK as targets of RSV which suppress cancer cell proliferation and induce apoptosis in the colon cancer cell line HT-29. RSV (150 μM) suppressed these pathways in the presence and absence of IGF-1, suggesting its role as a chemo-preventive agent even in obese condition.

Interspecific Variability for Antioxidant Activity and Phenolic Content Among Solanum Species

Total antioxidant activity was evaluated in 40 tuber-bearing Solanum species. Accessions identified in a broad screen as having high antioxidant activity were fine screened via high performance liquid chromatography (HPLC) to determine specific phenolic compounds present. The objective of the study was to identify tuber-bearing Solanum species that are higher in antioxidants than in currently available cultivated varieties and breeding lines, and to investigate the variability for this trait among accessions within species and genotypes within accessions. The identified accessions will be used as a source of germplasm to develop potato cultivars containing increased levels of antioxidant compounds. In a broad screen for total antioxidant activity, the 40 tuber-bearing species showed a wider range of variability than cultivated varieties and breeding lines. Solanum pinnatisectum and S. jamesii accessions consistently ranked among the highest in antioxidant activity and phenolic content. Based on the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, antioxidant activity in the wild species ranged from 48 to 824xa0μg trolox eq/gfw. HPLC analysis revealed that the phenolic content of these species was primarily composed of chlorogenic and caffeic acids. Other phenolics identified were p-coumaric acid, rutin hydrate, vanillic acid, epicatechin, t-cinnamic acid, gallic acid, and salicylic acid. The highest phenolic content found among the accessions was five-fold higher than the highest of the cultivated genotypes.ResumenLa actividad antioxidante total fue evaluada en 40 especies tuberíferas de Solanum. Las accesiones que mostraron actividad antioxidante en un tamizado amplio fueron sometidas a un tamizado más fino por medio de cromatografía líquida (HPCL) para determinar los compuestos fenólicos específicos presentes. El objetivo de este estudio fue identificar las especies tuberíferas de Solanum que tienen contenido más alto de antioxidantes que las variedades y líneas de mejoramiento e investigar la variabilidad de esta característica entre las accesiones dentro de especies y genotipos. Las accesiones identificadas serán usadas como fuente de germoplasma para desarrollar cultivares de papa que contengan niveles altos de compuestos antioxidantes. En un tamizado amplio para actividad total antioxidante, las 40 especies tuberíferas mostraron un rango más amplio de variabilidad que las variedades cultivadas y que las líneas mejoradas. Las accesiones de Solanum pinnatisectum y S. jamesii dieron consistentemente grados más altos en actividad antioxidante y contenido fenólico. En base a la prueba 2, 2-difenil-1-picrilhidrazil (DPPH), la actividad antioxidante en las especies silvestres fue de 48 a 824xa0μg trolox eq/gfw. El análisis HPLC reveló que el contenido de estas especies estaba principalmente compuesto de los ácidos clorogénico y cafeico. Otros fenoles identificados fueron ácido p-cumárico, rutina hidrato, ácido vanílico, epicatequín, ácido t-cinámico, ácido gálico y ácido salicílico. El contenido fenólico en las accesiones fue cinco veces más alto que en los genotipos cultivados.

Mitigation of Obesity-Promoted Diseases by Nigella sativa and Thymoquinone

Obesity is closely associated with increased incidence of cardiovascular diseases, cancer, insulin resistance, and immune dysfunction, and thus obesity-mitigation strategies should take into account these secondary pathologies in addition to promoting weight loss. Recent studies indicate that black cumin (Nigella sativa) has cardio-protective, anti-cancer, anti-diabetic, antioxidant, and immune-modulatory properties. While black cumin and/or its major bioactive constituent, thymoquinone have demonstrated bioactivity in a variety of disease models, the mechanisms of action are largely unknown. Given the growing interest in and the use of functional foods and nutraceuticals, as well as the increase in obesity and chronic diseases worldwide, further research into the therapeutic/preventive effects of black cumin may be beneficial.

Anthocyanins as Apoptotic Regulators

Bioactive compounds have been used traditionally in different cultures to promote human health. Anthocyanins (ACNs) are one of the most abundant dietary bioactive compounds and are responsible for the bright red, blue and purple colors of fruits and vegetables. There are over 600 different types of ACNs in nature, featuring six common aglycone structures, with different side chains attached. Although ACN bioavailability is low, ACNs and their gut metabolites possess biological activities that positively impact a variety of chronic diseases including cancer. This book chapter provides a brief summary of the synthesis and the bioavailability of ACNs and discusses the molecular mechanisms involved in ACN-induced apoptosis in cell culture, animal models and human clinical studies. Furthermore, ACN metabolism in vivo is also discussed, as the evidence indicates that the ACN metaxadbolites are important pro-apoptotic agents. We hope that the presented evidence will help influence future research in the direction of furthering the scientific understanding of ACN pro-apoptotic properties in cancer.

The Use of Low-Dose Electron-Beam Irradiation and Storage Conditions for Sprout Control and their Effects on Xanthophylls, Antioxidant Capacity, and Phenolics in the Potato Cultivar Atlantic

Low-dose electron-beam (e-beam) irradiation and storage conditions were evaluated for effectiveness in sprout control and their influence on health-promoting compounds in the potato cultivar Atlantic. Tubers were subjected to zero and 200xa0Gy and stored at either 4xa0°C or ambient temperature for 0, 10, 20, 75, and 110xa0days before evaluation. Xanthophyll content (Xan), antioxidant capacity (AOC), and phenolic content (PC) were quantified by spectrophotometric absorbance; xanthophyll and phenolic compounds were quantified with HPLC-DAD analysis. Tubers held at ambient conditions during storage lost weight and were visibly dehydrated. Tubers exposed to irradiation did not sprout; non-irradiated tubers sprouted, regardless of storage temperature. The exterior layer of tubers had greater total Xan, AOC, and PC than the interior layer, regardless of treatment. Storage time was the most influential factor, affecting Xan, AOC, and PC content. AOC, PC, and chlorogenic acid content increased within the first 10xa0days of storage, then declined with extended storage. Initially, the AOC and PC increased in irradiated tubers when compared to non-irradiated samples; however, little to no differences were observed once tubers were held in storage. Some exterior layer samples experienced an increase in Xan and PC during the later stages of storage and was believed to be associated with a concentration effect due to dehydration. E-beam irradiation inhibited sprouting during storage and prominent potato health promoting compounds were retained.ResumenSe evaluaron la irradiación con bajas dosis de un haz de electrones (e-beam) y las condiciones de almacenamiento para su efectividad en el control del brotamiento y su influencia en compuestos que promueven la salud en la variedad de papa Atlantic. Los tubérculos se expusieron a cero y 200xa0Gy y se almacenaron ya fuera a 4xa0°C o a temperatura ambiente por 0, 10, 20, 75, y 110 días antes de la evaluación. Se cuantificaron los contenidos de xantofilas (Xan), capacidad antioxidante (AOC) y el contenido fenólico (PC) por absorbancia espectrofotométrica; se cuantificaron las xantofilas y los compuestos fenólicos con un análisis de HPLC-DAD. Los tubérculos mantenidos en condiciones ambientales durante el almacenamiento perdieron peso y fueron visiblemente deshidratados. Los tubérculos expuestos a la radiación no brotaron; los no irradiados brotaron independientemente de la temperatura de almacenamiento. La capa exterior de tubérculos tuvieron más Xan, AOC, y PC totales que la capa interior, independientes del tratamiento. El tiempo de almacenamiento fue el factor de mayor influencia, afectando el contenido de Xan, AOC y PC. El contenido de AOC, PC, y ácido clorogénico aumentaron dentro de los primeros diez días de almacenamiento, después declinaron con almacenamiento extendido. Inicialmente, AOC y PC aumentaron en tubérculos irradiados cuando se compararon con mezclas no irradiadas; no obstante, se observaron pequeñas diferencias o ninguna una vez que los tubérculos se mantuvieron en almacén. Algunas muestras de la capa exterior experimentaron un incremento en Xan y PC durante las últimas etapas de almacenamiento y se pensó que pudieran asociarse con un efecto de concentración debido a la deshidratación. La irradiación inhibió el brotamiento durante el almacenamiento y se retuvieron los compuestos prominentes promotores de la salud en papa.

Abstract 2867: Anthocyanin and carotenoid rich fresh vs. processed colored potatoes suppress human colon cancer cell proliferation and elevate apoptosis via suppression of inducible nitric oxide synthase (iNOS) pathway

The potato (Solanum tuberosum L.) is the world9s 3rd largest food crop and the leading vegetable crop in the United States, with per capita consumption of about 126 lbs annually. Specialty/colored potatoes rich in anti-proliferative, pro-apoptotic and anti-inflammatory anthocyanins and/or carotenoids can be an attractive “delivery system” for these bioactive compounds in humans. Unlike other carotenoid- or anthocyanin-rich sources such as blueberries or pears, potatoes are stored and processed before consumption (80 lbs industrially processed potatoes/capita/year in the US). We previously demonstrated that colored potato extracts suppress cancer cell proliferation and induce apoptosis via both caspase-dependent and independent pathways; however, the effect of processing methods on these functional compounds is unknown. We hypothesized that potato bioactive compounds retain their chemoprotective properties against human colon cancer cells even after processing (chipping and baking) compared to the DMSO solvent controls. To test this hypothesis the anti-proliferative (WST assay), pro-apoptotic (cell death detection ELISA) and anti-inflammatory (iNOS pathway; immunoblots) properties of Atlantic (white; phenolics), Yukon Gold (yellow; carotenoids) and Purple Majesty (purple; anthocyanins) potato extracts before and after processing were determined using HCT116 p53+/+ and p53−/− human colon cancer cells. Potato extracts from processed potatoes (5 −15μg/ml) suppressed both p53+/+ and p53−/− human colon cancer cell proliferation and elevated apoptosis compared to the DMSO control after 24 hr incubation period. Similar results were observed after 48 and 72 hr of incubation. However, processing suppressed (p Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2867.

Abstract 1882: Resveratrol and grape seed extract synergistically elevate human colon cancer cell apoptosis and suppress cell proliferation via upregulation of p53 and suppression of Wnt/b-catenin signaling pathways

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DCnnThe health benefits of a diet rich in fruits and vegetables is partly due to the presence of a complex mixture of phytochemicals. The synergistic effect of phytochemicals may be responsible for chemopreventive/protective properties of fruits and vegetables. Resveratrol (RSV), a dietary stilbenoid and grape seed extract (GSE), rich in proanthocyanidins, are marketed as popular dietary supplements and have shown to suppress carcinogenesis in vivo. However, we and others have shown that both RSV (> 100 μM) and GSE (at or > 50 μg/ml) exert anti-cancer properties against human colon cancer cells only at very high doses. We hypothesized that RSV and GSE work together synergistically, at low doses (RSV 50 µM) suppressed (p < 0.05) proliferation in both p53 +/+ and -/- cell lines. RSV and GSE combination (RSV- 25 μM and GSE − 50 µg/ml - combination index value ∼ 0.7) synergistically suppressed (p < 0.05) colon cancer cell proliferation. RSV and GSE in combination also elevated (p < 0.05) apoptosis irrespective of p53 status in colon cancer cell lines, however the effect was more pronounced (p < 0.001) in p53 +/+ cells. RSV and GSE in combination suppressed (p < 0.05) nuclear translocation of β-catenin, a downstream effector of Wnt pathway, that plays a critical role in colon cancer cell proliferation in both p53 +/+ and -/- cell lines. Apoptosis strongly correlated (p < 0.001 in both cell lines) with pp53 levels and Bax/Bcl-2 ratio that play a crucial role in mitochondrial apoptotic pathway. For the first time, we report that addition of resveratrol to grape seed extract synergistically elevates apoptosis and suppresses human colon cancer cell proliferation via upregulation of p53 and suppression of Wnt/β-catenin pathways. This explains why no magic bullet approach can provide health benefits similar to the synergistic combination of numerous phytochemicals in fruits and vegetables. Focal adhesion kinase (Fak) mediated integrin signaling pathway lies upstream of the well studied p53, PI3K/Akt, Wnt/β-catenin and Ras signaling pathways, and might provide insight into how RSV and GSE combination governs colon cancer cell apoptosis and proliferation. We will examine this possibility in future studies using appropriate in vitro and in vivo models.nnCitation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1882.