Cancer Chemopreventive Compounds Research Articles

Synergic Role of Dietary Bioactive Compounds in Breast Cancer Chemoprevention and Combination Therapies.

Breast cancer is the most common tumor in women. Chemotherapy is the gold standard for cancer treatment; however, severe side effects and tumor resistance are the major obstacles to chemotherapy success. Numerous dietary components and phytochemicals have been found to inhibit the molecular and signaling pathways associated with different stages of breast cancer development. In particular, this review is focused on the antitumor effects of PUFAs, dietary enzymes, and glucosinolates against breast cancer. The major databases were consulted to search in vitro and preclinical studies; only those with solid scientific evidence and reporting protective effects on breast cancer treatment were included. A consistent number of studies highlighted that dietary components and phytochemicals can have remarkable therapeutic effects as single agents or in combination with other anticancer agents, administered at different concentrations and via different routes of administration. These provide a natural strategy for chemoprevention, reduce the risk of breast cancer recurrence, impair cell proliferation and viability, and induce apoptosis. Some of these bioactive compounds of dietary origin, however, show poor solubility and low bioavailability; hence, encapsulation in nanoformulations are promising tools able to increase clinical efficiency.

STUDY OF CHEMOPREVENTIVE ROLE OF PADDY HUSK ON CERVICAL ADENOCARCINOMA HUMAN CELL LINE (HELA CELLS)

Objective: Cervical cancer is the fourth most prevalent cancer type and the fourth primary cause of cancer-related death among women worldwide. The deficiencies of current treatments, including severe side effects and the inability to prevent progression to the metastatic stage, necessitate the investigation of alternative agents. Methods: The chemopreventive approach employing natural products such as Paddy Husk is acquiring considerable traction in the scientific community. This study examined the chemopreventive effects of Paddy Husk on HeLa cervical cancer cells. Using the TBEA method, the IC50 of the husk was determined. To evaluate the antiproliferative activity with prolonged treatment exposure, HeLa cells treated with the IC50 value were incubated for 8 days. Results: The results demonstrated that Paddy Husk extract effectively inhibited the proliferation of HeLa cells throughout the duration of the treatment. Examination under the microscope revealed that Paddy Husk extract induces apoptotic characteristics, including cell contraction, membrane rounding, membrane blebbing, the formation of apoptotic bodies, and vacuolation. A mouse skin fibroblast cell line (L929) was used to assess the in vitro safety of paddy refuse extracts at various concentrations, revealing no toxic effects on normal L929 cells. Conclusion: These findings are essential for advancing our knowledge and recognizing the potential function of Paddy Husk compounds in cervical cancer chemoprevention.

2,4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone from Cleistocalyx nervosum var. paniala seeds attenuated the early stage of diethylnitrosamine and 1,2-dimethylhydrazine-induced colorectal carcinogenesis

BackgroundDichloromethane extract of Cleistocalyx nervosum var. paniala seeds exhibited an anticarcinogenicity against chemically-induced the early stages of carcinogenesis in rats. This study aimed to identify anticarcinogenic compounds from C. nervosum seed extract (CSE). MethodsSalmonella mutation assay was performed to determine mutagenicity and antimutagenicity of partially purified and purified compounds of CSE. The anticarcinogenic enzyme-inducing activity was measured in Hepa1c1c7. Moreover, the anticancer potency was examined on various human cancer cell lines. The anticarcinogenicity of DMC was investigated using dual-organ carcinogenicity model. The number of preneoplastic lesions was evaluated in the liver and colon. The inhibitory mechanisms of DMC on liver- and colorectal carcinogenesis were investigated. ResultsSix partially purified fractions (MK1 – MK6) and purified compounds, including 2,4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) and hariganetin, were obtained from CSE. Among these fractions, MK4 and DMC presented the greatest antimutagenicity against indirect mutagens in bacterial model. Moreover, MK5 possessed an effective anticarcinogenic enzyme inducer in Hepa1c1c7. The MK4, DMC and CSE showed greater anticancer activity on all cell lines and exhibited the most effective toxicity on colon cancer cells. Furthermore, DMC inhibited the formation of colonic preneoplastic lesions in carcinogens-treated rats. It reduced PCNA-positive cells and frequency of BCAC in rat colon. DMC also enhanced the detoxifying enzyme, GST, in rat livers. ConclusionsDMC obtained from CSE may be a promising cancer chemopreventive compound of colorectal cancer process in rats. It could increase detoxifying enzymes and suppress the cell proliferation process resulting in prevention of post-initiation stage of colorectal carcinogenesis.

Current Knowledge and Challenges on the Development of a Dietary Glucosinolate Database in the United States.

Glucosinolates (GSLs) are a group of cancer chemopreventive sulfur-containing compounds found primarily in Brassica vegetables. The goals of this study were to summarize the current knowledge and discuss the challenges of developing a dietary GSL database for US foods. A systematic literature search was conducted for the period 1980-2020. Thirty articles were found to meet all inclusion and exclusion criteria; 27 GSLs were reported in 16 different vegetables. GSLs identified and quantified ranged from 3 for winter cress to 16 for cabbage. In general, the experimental designs of these 30 studies did not fully consider the factors related to the data quality. Enormous variations of GSLs are observed between different vegetables and in the same vegetables. In conclusion, the studies on GSLs in commonly consumed vegetables are still limited, and some data may be outdated. Currently available data are not sufficient to develop a valid GSL database in the United States.

Evaluation of the chemopreventive effect of selected medicinal plants extracts via induction of the Nrf2 in a modified model of breast cancer cells: identification of bioactive lead compounds.

The cancer chemopreventive potential of various solvent extracts from six medicinal plants was evaluated by their ability to activate the transcription factor Nrf2 using AREc32 cells, which contain a luciferase gene under the control of antioxidant responsive element promoters. Nrf2 regulates the expression of many detoxification enzymes, making it an ideal target for cancer prevention. The present research revealed Zanthoxylum zanthoxyloides extracts as promising sources of cancer chemopreventive compounds. Bioassay-guided isolation of the Z. Zanthoxyloides methanol extract resulted in the isolation of N-methylatanine, N-methylplatydesminecation, sesamin and skimmianine. Among these compounds, skimmianine was identified as the most active compound, causing a 2.8-fold increase in luciferase activity. Skimmianine and other related quinolone alkaloids could represent an appropriate starting scaffold for the development of new chemopreventive cancer drugs.

Simultaneous Quantification of Hederacoside C and α-hederin in Hedera Nepalensis K.Koch Using HPLC-UV

This study develops a high performance liquid chromatography with ultraviolet detection (HPLC-UV) for simultaneous quantification of hederacoside C and α-hederin in Hedera nepalensis K. Koch. The method proposed in this study was validated in terms of the analytical parameters such as high repeatability, high accuracy and good sensitivity. The method was used to determine the content of hederacoside C and α-hederin in Hedera nepalensis K. Koch, which had been collected in Ha Giang, Lao Cai and Lai Chau. The study results show that the content of hederacoside C and the content of α-hederin ranged from 0.40 to 4.01% and 0.21 – 0.54% based on absolute dry mass, respectively.
 Keywords
 Hedera nepalensis K. Koch, hederacoside C, α-hederin, HPLC-UV.
 References
 [1] L. Jafri, et al, In vitro assessment of antioxidant potential and determination of polyphenolic compounds of Hedera nepalensis K. Koch, Arabian Journal of Chemistry. 10 (2017) 3699-3706. https://doi.org/10.1016/j.arabjc.2014.05.002.[2] S. Saleem, et al, Plants Fagonia cretica L, and Hedera nepalensis K. Koch contain natural compounds with potent dipeptidyl peptidase-4 (DPP-4) inhibitory activity, Journal of ethnopharmacology. 156 (2014) 26-32. https://doi.org/10.1016/j.jep.2014.08.017[3] D.H. Bich, Medicinal plants and animals for medicine in Vietnam, Vol 1, Science and Technics Publishing House, Hanoi, 2006 (in Vietnamese).[4] National Institute Of Medicinal Materials, List of medicinal plants in Vietnam, Science and Technics Publishing House, Hanoi, 2016 (in Vietnamese).[5] L. Jafri, et al, Hedera nepalensis K. Koch: A Novel Source of Natural Cancer Chemopreventive and Anticancerous Compounds, Phytotherapy research. 30(3) (2016) 447-453. https://doi.org/10.1002/ptr.5546. [6] S. Kanwal, et al, Antioxidant, antitumor activities and phytochemical investigation of Hedera nepalensis K. Koch, an important medicinal plant from Pakistan, Pakistan Journal of Botany. 43 (2011) 85-89. [7] G. Uddin, et al, Biological screening of ethyl acetate extract of Hedera nepalensis stem, African Journal of Pharmacy and Pharmacology. 6(42) (2012) 2934-2937. https://doi.org/10.5897/AJPP12.828 [8] H. Kizu, et al, Studies on Nepalese Crude Drugs, III, On the Saponins of Hedera nepalensis K. Koch, Chemical and Pharmaceutical Bulletin. 33(8) (1985) 3324-3329. https://doi.org/0.1248/cpb.33.3324[9] X. Tong, et al, Extraction and GC-MS Analysis of Volatile Oil from Hedera nepalensis var sinensis, Fine Chemicals. 24(6) (2007) 559-561. [10] EDQM, European Pharmacopoeia, fifth ed., Council of Europe, France, 2015. [11] N.T.H. Mai, et al, Simultaneous Quantification of Hederacoside C and α-Hederin from the Leaves of Hedera helix L. by HPLC, Journal of Medicinal Material. 21(6) (2016). (in Vietnamese).[12] L. Havlíková, et al, Rapid Determination of α-Hederin and Hederacoside C in Extracts of Hedera helix Leaves Available in the Czech Republic and Poland, Natural product communications. 10(9) (2015). https://doi.org/10.1177/1934578X1501000910[13] M. Yu, et al, Determination of Saponins and Flavonoids in Ivy Leaf Extracts Using HPLC-DAD, Journal of Chromatographic Science. 53(4) (2014) 478-483. https://doi.org/10.1093/chromsci/bmu068.[14] EMEA, Validation of analytical procedures: text and methodology Q2 (R1), in International conference on harmonization, Geneva, Switzerland, 2005. [15] W. Horwitz, Official methods of analysis, 12 ed., Vol 1, Association of Official Analytical Chemists, Washington DC, 1975.

Dark sweet cherry (Prunus avium) phenolics enriched in anthocyanins exhibit enhanced activity against the most aggressive breast cancer subtypes without toxicity to normal breast cells

Abstract This study assessed dark sweet cherry (DSC) phenolics as chemopreventive/chemotherapeutics against aggressive breast cancer subtypes. DSC phenolics in whole extract (WE) and fractions enriched in phenolic acids (F1), flavonols (F3) and proanthocyanidins (F4) inhibited breast cancer cell growth with potency MDA-MB-453 > MDA-MB-231 ∼ BT-474, without toxicity to MCF-10A normal breast cells, except F3 that inhibited BT-474 and MCF-10A cells with similar toxicity. DSC anthocyanins (F2) inhibited breast cancer cell lines with similar potencies without toxicity to MCF-10A cells. Mechanisms for WE, F2 and F4 breast anticancer activity may be mediated by reduction of oxidative stress, Akt/mTOR, p38, and survivin regulation, suggesting antiproliferative and apoptotic mechanisms. F2 significantly downregulated mRNA levels of invasive/metastatic biomarkers Sp1, Sp4, and VCAM-1, and Sp1 protein suggesting an enhanced chemopreventive/chemotherapeutic potential of DSC anthocyanins. Further studies are needed to elucidate underlying mechanisms of DSC phenolics as natural breast cancer chemopreventive compounds.

Comparative Analysis of Different DNA Extraction Methods and Preliminary Analysis of Genetic Diversity of Hedera nepalensis K. Koch. in Vietnam Based on GBSSI Marker

Though the ivy (Hedera nepalensis K. Koch.) has long been utilized in traditional medicine, its genome information is very limited. For plants, an effective method of DNA extraction is a very important step which greatly affects subsequent genetic analyses. In this study, four different methods of DNA extraction from dry leaves were used. A comparison of different protocols resulted in the yield of extracted DNA that ranged from 10.5 to 437.4 ng/μl and with a purity ranged from 1.8 to 2.2. Based on the PCR results of GBSSI gene, Gene JET Plant Genomic DNA Purification Mini Kit is the most optimal extraction method for Vietnam ivy’s dry leaves. A preliminary analysis of the phylogenetic tree based on the GBSSI marker showed that ivy growing in a number of northern mountainous provinces of Vietnam belonged to the H. nepalensis K. Koch species. The high - quality total DNA will allow us to amplify different DNA markers, providing valuable genetic information to preserve and develop medicinal resources in Vietnam.
 Keywords
 GBSSI, Hedera nepalensis K. Koch, DNA extraction.
 References
 [1] J. Ackerfield, J. Wen, A morphometric analysis of Hedera L. (the ivy genus, Araliaceae) and its taxonomic implications, Adansonia Sér. 24 (2002) 187-212.[2] U.S. National Plant Germplasm System, Taxon: Hedera nepalensis K. Koch, https://npgsweb.ars -grin.gov/gringlobal/taxonomydetail.aspx?id= 18567, 2019 (accessed 21 March 2019). [3] L. Jafri, S. Saleem, T.P. Kondrytuk, I.Q. Haq, N. Ullah, J.M. Pezzuto, B. Mirza, Hedera nepalensis K. Koch: A Novel Source of Natural Cancer Chemopreventive and Anticancerous Compounds, Phytotherapy Reserch. 30 (2016) 447-453.[4] S. Saleem, L. Jafri, I. Haq, L.C. Chang, D. Calderwood, B.D. Green, B. Mirza, Plants Fagonia cretica L. and Hedera nepalensis K. Koch contain natural compounds with potent dipeptidyl peptidase-4 (DPP-4) inhibitory activity, Journal of Ethnopharmacology. 156 (2014) 26-32.[5] W.J. Hashmi, H. Ismail, F. Mehmood, B. Mirza, Neuroprotective, antidiabetic and antioxidant effect of Hedera nepalensis and lupeol against STZ+ AlCl3 induced rats model, DARU: Journal of faculty of Pharmacy, Tehran University of Medical Sciences. 26 (2018) 179-190.[6] H. Ismail, A. Rasheed, I.U. Haq, L. Jafri, N. Ullah, E. Dilshad, M. Sajd, B. Mirza, Five indigenous plants of Pakistan with Antinociceptive, anti-inflammatory, antidepressant, and anticoagulant properties in Sprague Dawley rats, Evidence-based Complementary and alternative medicine 2017 (2017) 1-10.[7] A. Mitchell, J. Wen. Phylogenetic utility and evidence for multiple copies of granule-bound starch synthase I (GBSSI) in Araliaceae, Taxon 53 (2004) 29-44.[8] M.A. Saghai-Maroof, K.M. Soliman, R.A. Jorgensen, R.W.L. Allard, Ribosomal DNA spacer-length polymorphisms in barley: Mendelian inheritance, chromosomal location, and population dynamics, Proceeding of the National Academy of Sciences of the USA. 81 (1984) 8014-8018.[9] M. Elias, G.S. Mühlen, D. McKey, A.C. Roa, J. Tohme, Genetic diversity of traditional South American landraces of cassava (Manihot esculenta Crantz): an analysis using microsatellites, Economic Botany. 58 (2004) 242-256.[10] B.D. Lade, A.S. Patil, H.M. Paikrao, Efficient genomic DNA extraction protocol from medicinal rich Passiflora foetida containing high level of polysaccharide and polyphenol, Springerplus. 3 (2014) 1-7.[11] J.H. Cota-Sánchez, K. Remarchuk, K. Ubayasena, Ready-to-use DNA extracted with a CTAB method adapted for herbarium specimens and mucilaginous plant tissue, Plant Molecular Biology Reporter. 24 (2006) 161.[12] J. Zhang, J.M. Stewart, Economical and rapid method for extracting cotton genomic DNA, Journal of Cotton Science. 4 (2000) 193-201.[13] T. Li, H. Pan, Y. Feng, H. Li, Y. Zhao, Bioactivity-guided isolation of anticancer constituents from Hedera nepalensis K. Koch, South African Journal of Botany. 100 (2015) 87-93.[14] L. Jafri, S. Saleem, N. Ullah, B. Mirza, In vitro assessment of antioxidant potential and determination of polyphenolic compounds of Hedera nepalensis K. Koch, Arabian Journal of Chemistry. 10 (2017) S3699-S3706.[15] B. Ahmad, N. Munir, S. Bashir, S. Azam, I. Khan, M. Ayub, Biological screening of Hedera nepalensis, Journal of Medicinal Plants Research. 6 (2012) 5250-5257.[16] K.H.E. Koch, Hortus Dendrologicus, F. Schneider & Co., Berlin, 1985, pp 250.[17] A. Rehder, New species, varieties and combinations from the herbarim and the collections of the Arnold arboretum, Journal of the Arnold Arboretum. 4 (1923) 250.

Lung Cancer Chemopreventive Activity of Patulin Isolated from Penicillium vulpinum.

Lung cancer is the most lethal form of cancer in the world. Its development often involves an overactivation of the nuclear factor kappa B (NF-κB) pathway, leading to increased cell proliferation, survival, mobility, and a decrease in apoptosis. Therefore, NF-κB inhibitors are actively sought after for both cancer chemoprevention and therapy, and fungi represent an interesting unexplored reservoir for such molecules. The aim of the present work was to find naturally occurring lung cancer chemopreventive compounds by investigating the metabolites of Penicillium vulpinum, a fungus that grows naturally on dung. Penicillium vulpinum was cultivated in Potato Dextrose Broth and extracted with ethyl acetate. Bioassay-guided fractionation of this extract was performed by measuring NF-κB activity using a HEK293 cell line transfected with an NF-κB-driven luciferase reporter gene. The mycotoxin patulin was identified as a nanomolar inhibitor of TNF-α-induced NF-κB activity. Immunocytochemistry and Western blot analyses revealed that its mechanism of action involved an inhibition of p65 nuclear translocation and was independent from the NF-κB inhibitor α (IκBα) degradation process. Enhancing its interest in lung cancer chemoprevention, patulin also exhibited antiproliferative, proapoptotic, and antimigration effects on human lung adenocarcinoma cells through inhibition of the Wnt pathway.

Apoptotic efficiency of aqueous extracts of turmeric, garlic and their active compounds in combination with Tamoxifen in lung and oral cancers: A comparative study

Anticancer treatment against oral and lung cancers has caught the eye of oncologist and researchers worldwide as most common cause deaths in India and worldwide is due to these cancers and most of the treatment strategies employed are not showing any effectiveness against neoplastic ability of the cancers. One of the reasons for cancer deaths could be because of poor prognosis and associated therapies. The existing cancer agents are being re-evaluated and development of new mechanisms of treatment being explored continuously, but it’s inadequate in offering treatment. Therefore, endeavors for new anticancer agents with high efficacy and considerable side effects still going on. The literature reviews shows numerous medicinal plants exhibiting anti-proliferative, pro-apoptotic, anti-metastatic and anti-angiogenic properties and these effects were reported by conducting both in vitro experiments and animal studies. Use of natural phytochemical compounds in cancer chemoprevention is an emerging strategy to forestall the cancer progression or cure cancer.In the present study we have attempted to evaluate the efficacy of Curcumin longa and Allium sativum aqueous extracts individually and in combination with its active compounds (Curcumin and Quercetin) and also with Tamoxifen hydrochloride. Our results suggest that aqueous extracts of Curcumin longa and Allium sativum were effective in inducing apoptosis and cell death in two immortal cell lines i.e. A549 and SCC-9 (Adeno carcinoma of lung, squamous cell carcinoma of tongue), but there was no apoptosis or cell senescence in normal cell line (HEK 293). There was significant increase in apoptosis and cell senescence in combination therapy. Hence a combination of natural extracts along with Tamoxifen can be considered an alternate in cancer treatments but this requires more research.

Challenges of developing a valid dietary glucosinolate database

Glucosinolates are a group of important cancer chemo-preventive sulfur-containing compounds in cruciferous vegetables. To estimate their dietary intake, there is a great need to develop a valid glucosinolate database. The aim of this study was to investigate the key challenges in developing such database. First, three commonly used enzyme deactivation methods (blanching, steaming and microwaving) were compared with samples of raw untreated broccoli and kale. Steaming and microwaving were found to effectively deactivate myrosinase, both led to significantly higher glucosinolate values that blanching (∼15–50% higher). Glucosinolates in untreated broccoli was similar to that of blanching broccoli, while glucosinolates were not detected in untreated kale. Heat treatment was also shown to alter the profiles of individual glucosinolate. Quantification of total glucosinolates of four common vegetables was compared by the two most commonly used analytical methods (ISO 9167-1 method and cyclocondensation method). Except for kale, the results from ISO 9167-1 were much higher (∼6–8 fold) than that from cyclocondensation method in other three vegetables. In conclusion, the sample preparation procedure, analytical method for quantification and the compounds to be measured must be considered and validated in order to develop a valid dietary glucosinolate database.

Abstract 2240: “Smart” selenium compound ISC-4 inhibits androgen receptor signaling and induces ROS- and p53-dependent apoptosis in LNCaP prostate cancer cells

Abstract “Smart” selenium compound phenylbutyl isoselenocyanate (ISC-4) was developed by substituting sulfur in cancer chemopreventive compound phenylbutyl isothiocyanate (PBITC) with selenium, resulting in increased anti-cancer activity in several melanoma and colon cancer cell lines. The in vivo anticancer beneficial effects of ISC-4 have been reported in both melanoma and colon cancer mouse models as well. To explore the potential chemopreventive attributes of ISC-4 against prostate carcinogenesis, we selected LNCaP cells (with wild type p53 and functional androgen receptor (AR) signaling) to examine the growth suppression and apoptosis responses in cell culture and interrogated signaling mechanisms through pharmacological and siRNA knockdown approaches. Results show that when compared with PBITC, ISC-4 was more potent at suppressing cell growth and inducing apoptotic cell death in LNCaP cells. ISC-4 induced caspase-mediated apoptosis (as evidenced by cleavage of PARP) in dose- and time-dependent manners in association with decreased AR and its best known target prostate specific antigen (PSA) protein abundance and upregulation of p53-DNA damage response (DDR) protein expression levels: p53, its canonical target p21, and p-H2AX that marks DNA double-strand break sites. Similar to the rapid induction of reactive oxygen species (ROS) by isothiocyanates, ISC-4 exposure resulted in increased dihydroethidium-detectable ROS in a concentration-dependent manner. Preincubation with the ROS scavenger N-Acetyl-L-cysteine (NAC, 10 µM to 2 mM), markedly reduced ISC-4-induced cell death and attenuated p53, p21 and p-H2AX. Moreover, siRNA knockdown of p53 did not suppress ROS production, but decreased ISC-4-induced Annexin V-positive apoptosis, PARP cleavage and the DDR proteins. Taken together, these data suggest that ISC-4 inhibits LNCaP cell growth and survival with concomitant suppression of AR signaling and induction of ROS-p53-DDR mediated apoptosis. Given the pivotal significance of AR signaling in prostate epithelial survival, cancer genesis and progression, and the preservation of wild type p53 in precancerous lesions and early stage prostate cancer, our findings suggest attractive chemopreventive potential of ISC-4 against prostate carcinogenesis. Citation Format: Wei Wu, Kartick Pramanik, Cheng Jiang, Shantu Amin, Arun K. Sharma, Junxuan Lu. “Smart” selenium compound ISC-4 inhibits androgen receptor signaling and induces ROS- and p53-dependent apoptosis in LNCaP prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2240. doi:10.1158/1538-7445.AM2017-2240

Gene expression changes in colon tissues from colorectal cancer patients following the intake of an ellagitannin-containing pomegranate extract: a randomized clinical trial

The clinical evidence of dietary polyphenols as colorectal cancer (CRC) chemopreventive compounds is very weak. Verification in humans of tissue-specific molecular regulation by the intake of polyphenols requires complex clinical trials that allow for the procurement of sufficient pre- and postsupplementation tissue samples. Ellagitannins (ETs), ellagic acid (EA) and their gut microbiota-derived metabolites, the urolithins, modify gene expression in colon normal and cancer cultured cells. We conducted here the first clinical trial with 35 CRC patients daily supplemented with 900 mg of an ET-containing pomegranate extract (PE) and evaluated the expression of various CRC-related genes in normal and cancerous colon tissues before (biopsies) and after (surgical specimens) 5–35 days of supplementation. Tissues were also obtained from 10 control patients (no supplementation) that confirmed a large, gene- and tissue-specific interindividual variability and impact of the experimental protocol on gene expression, with some genes induced (MYC, CD44, CDKN1A, CTNNB1), some repressed (CASP3) and others not affected (KRAS). Despite these issues, the consumption of the PE was significantly associated with a counterbalance effect in the expression of CD44, CTNNB1, CDKN1A, EGFR and TYMs, suggesting that the intake of this PE modulated the impact of the protocol on gene expression in a gene- and tissue-specific manner. These effects were not associated with the individuals' capacity to produce specific urolithins (i.e., metabotypes) or the levels of urolithins and EA in the colon tissues and did not reproduce in vitro effects evidencing the difficulty of demonstrating in vivo the in vitro results.

Isolation of Chemoresistant Cell Subpopulations.

Chemoresistance is a major challenge for cancer therapy and drives tumor relapse. The emergence, within the treated tumor mass, of specific cancer cell subpopulations endowed with high tolerance to the microenvironment stress induced by therapy is being growingly recognized as a mechanism of tumor progression. To obtain detailed information with regard to the pathways underlying survival, expansion, and microenvironmental cross talk of such chemoresistant cell subpopulations may be instrumental for cancer chemoprevention. Additionally, the obtained cell subpopulations may be used for direct screening of cancer chemopreventive compounds, in appropriate experimental settings. Here we report detailed experimental procedures that we and others have setup in order to obtain cell cultures enriched for chemoresistant cells from both malignant pleural mesothelioma specimens and primary cell cultures. We provide indications for the purification and characterization of those chemoresistant cell populations and to generally validate the obtained enriched cell populations for their chemoresistance.

Role of natural phenolic compounds in cancer chemoprevention via regulation of the cell cycle.

Natural phenolic compounds have been considered as one of the interesting secondary metabolites for their chemopreventive and chemotherapeutic effects in cancer for a long time. These are a large and diverse family of phytochemicals classified into several subgroups such as simple phenols, lignans, phenylpropanoids, flavonoids, coumarins, etc. The antioxidant potential of phenolic compounds is almost bolded in the treatment and prevention of cancer. Due to the concerns on the diverse effects of antioxidants in cancer, differentiation and clarification of their anti-neoplastic mechanisms are necessary. An important mechanism for phenolic compounds is related to their direct effect on the cell cycle progression, which has not been discussed in detail so far. This study aims to criticize the evidence on regulatory mechanisms of phenolic compounds in the cell cycle. Recent studies indicate that phenolic compounds from several subgroups significantly inhibit the proliferation of different cancer cells. The structural diversity of these compounds influences various components involved in cell cycle regulation. Forming active metabolites and sensitizing cancerous cells to chemotherapeutic medicines are additional values of these compounds. In the recent years, many studies on neoplastic cell cultures have been carried out to investigate the mechanisms of action of these compounds but dissimilarity of in vitro systems in comparison with human body in terms of metabolism and bioavailability is a major concern. Therefore, further studies are still needed.

The Immunomodulation and Anti-Inflammatory Effects of Garlic Organosulfur Compounds in Cancer Chemoprevention

Garlic (Allium sativum) has been used for centuries as a prophylactic and therapeutic medicinal agent. Importantly, garlic has been suggested to have both cancer-preventive potential as well as significant enhancing effects on the immune system. While these observations are supported experimentally both in vitro and in vivo, the impact of garlic in assisting the immune system in the prevention of cancer still lacks experimental confirmation. Studies addressing the immunomodulatory effects of garlic reveal conflicting data as to pro- or anti-inflammatory responses depending on the particular experimental set-ups and the garlic preparation used (i.e. garlic extract versus chemically pure garlic compounds). Here we provide an overview of the chemistry of the major garlic organosulfur compounds, summarize the current understanding and propose a link between the immunomodulating activity of garlic and the prevention of cancer. We hypothesize that garlic rather elicits anti-inflammatory and anti-oxidative responses that aid in priming the organism towards eradication of an emerging tumor.

Cytotoxic mechanism of novel compound jiangxienone from Cordyceps jiangxiensis against cancer cells involving DNA damage response pathway

Jiangxienone is a novel compound recently purified from the traditional Chinese medicinal mushroom Cordyceps jiangxiensis and was reported to show potent cytotoxicity against cancer cells. However, its mechanism of action remains unclear. In this work, the underlying mechanism of jiangxienone against human gastric cancer cells HGC-27 was investigated using whole-genome microarray. The results demonstrated that jiangxienone significantly decreased cell population of various human cancer cell lines, while slightly inhibited the colony formation of stromal cells from murine marrow even at a high concentration. Differential gene expression profiling indicated that the cytotoxic action of jiangxienone against HGC-27 is closely related to the DNA damage response pathway, which was evident by the identification of 23 DNA damage response-associated genes, such as XRCC4/5/6, NBS1, RAD51, and BRCA1/2. By using gel retardation assays, UV absorption spectrometry and single-cell gel electrophoresis, it was found that jiangxienone could bind to DNA and inhibit cancer cell growth. The above results indicated that the cytotoxic mechanism of jiangxienone against cancer cells was involved in the DNA damage response pathway. The findings will be helpful to the development of useful cancer chemopreventive compounds from C. jiangxiensis.

Shrimp lipids: a source of cancer chemopreventive compounds.

Shrimp is one of the most popular seafoods worldwide, and its lipids have been studied for biological activity in both, muscle and exoskeleton. Free fatty acids, triglycerides, carotenoids, and other lipids integrate this fraction, and some of these compounds have been reported with cancer chemopreventive activities. Carotenoids and polyunsaturated fatty acids have been extensively studied for chemopreventive properties, in both in vivo and in vitro studies. Their mechanisms of action depend on the lipid chemical structure and include antioxidant, anti-proliferative, anti-mutagenic, and anti-inflammatory activities, among others. The purpose of this review is to lay groundwork for future research about the properties of the lipid fraction of shrimp.

Evaluation of skin cancer chemoprevention potential of sunscreen agents using the Epstein–Barr virus early antigen activation in vitro assay

In our continuing search for novel cancer chemopreventive compounds of natural and synthetic origin, we have evaluated 14 commonly used ultraviolet (UV) sunscreen agents (designated UV-1 to UV-14) for their skin cancer chemoprevention potential. They belong to 8 different chemical categories: aminobenzoate (UV-5, UV-7, UV-8 and UV-14), benzophenone (UV-1, UV-2, UV-3 and UV-13), benzotriazole (UV-10), benzyloxyphenol (UV-9), cinnamate (UV-6), quinolone (UV-4), salicylate (UV-11) and xanthone (UV-12). In the in vitro assay employed, the sunscreens were assessed by their inhibition of the Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in human lymphoblastoid Raji cells. All sunscreens tested were found to exhibit anti-tumour promoting activity: listed in decreasing order, moderate (UV-11, UV-2, UV-7, UV-12, UV-3, UV-9 and UV-14) to weak (UV-1, UV-6, UV-8, UV-16, UV-5, UV-4 and UV-10) with octyl salicylate (UV-11) as the most potent and drometrizole (UV-10) as the least potent among the compounds evaluated. A plausible relationship between the antioxidant property of sunscreens and their ability to promote anti-tumour activity was noted. The results call for a comprehensive analysis of skin cancer chemoprevention potential of currently used UV sunscreen agents around the globe to identify those with the best clinical profile.

Identifying and Characterizing Binding Sites on the Irreversible Inhibition of Human Glutathione S‐Transferase P1‐1 by S‐Thiocarbamoylation

Human glutathione S-transferase P1-1 (hGST P1-1) is involved in cell detoxification processes through the conjugation of its natural substrate, reduced glutathione (GSH), with xenobiotics. GSTs are known to be overexpressed in tumors, and naturally occurring isothiocyanates, such as benzyl isothiocyanate (BITC), are effective cancer chemopreventive compounds. To identify and characterize the potential inhibitory mechanisms of GST P1-1 induced by isothiocyanate conjugates, we studied the binding of GST P1-1 and some cysteine mutants to the BITC-SG conjugate as well as to the synthetic S-(N-benzylcarbamoylmethyl)glutathione conjugate (BC-SG). We report here the inactivation of GST P1-1 through the covalent modification of two Cys47 residues per dimer and one Cys101. The evidence has been compiled by isothermal titration calorimetry (ITC) and electrospray ionization mass spectrometry (ESI-MS). ITC experiments suggest that the BITC-SG conjugate generates adducts with Cys47 and Cys101 at physiological temperatures through a corresponding kinetic process, in which the BITC moiety is covalently bound to these enzyme cysteines through an S-thiocarbamoylation reaction. ESI-MS analysis of the BITC-SG incubated enzymes indicates that although the Cys47 in each subunit is covalently attached to the BITC ligand moiety, only one of the Cys101 residues in the dimer is so attached. A plausible mechanism is given for the emergence of inactivation through the kinetic processes with both cysteines. Likewise, our molecular docking simulations suggest that steric hindrance is the reason why only one Cys101 per dimer is covalently modified by BITC-SG. No covalent inactivation of GST P1-1 with the BC-SG inhibitor has been observed. The affinities and inhibitory potencies for both conjugates are high and very similar, but slightly lower for BC-SG. Thus, we conclude that the presence of the sulfur atom from the isothiocyanate moiety in BITC-SG is crucial for its irreversible inhibition of GST P1-1.