Inhibition of Akt signaling by the lignan matairesinol sensitizes prostate cancer cells to TRAIL-induced apoptosis

The What and Who of Dietary Lignans in Human Health: Special Attention to Estrogen Effects and Safety Evaluation

Lignans are a group of phenolic compounds found in plant-based diets. The human body can obtain lignans through diet, which are then metabolized into enterolignans. The enterolignans have been linked to several health benefits, including anticancer, anti-inflammatory, antioxidant effects, and estrogen effects. This review explores the relationship between the estrogenic effects of lignans and health. This review not only considers the estrogen-like activity of lignans but also discusses the safe dosage of lignans at different life stages. In addition, this review also identified other types of bioactive compounds that can act synergistically with lignans to promote health. Studies have shown that lignan administration during pregnancy and lactation reduces the risk of breast cancer in offspring. Further studies are needed to investigate the estrogenic safety effects of lignan on pregnant women and children. Whether lignans combine with other nutrients in complex food substrates to produce synergistic effects remains to be investigated. This review provides a basis for future studies on the safe dose of lignan and recommended dietary intake of lignan. We believe that the acquired as discussed here has implications for developing dietary therapies that can promote host nutrition and modulate estrogenic diseases.

Honokiol inhibits the growth of hormone-resistant breast cancer cells: its promising effect in combination with metformin

Background and purpose

Primary and metastatic breast cancers still represent an unmet clinical need for improved chemotherapy and hormone therapy. Considerable attention has been paid to natural anticancer compounds, especially lignans. The study aimed to evaluate the activity of several lignans against breast cancer cells and assess the effect of leading lignans on signaling pathways in combination with metformin.

Experimental approach

Human breast cancer cell lines MCF7 (hormone-dependent), MDA-MB-231, and SKBR3 (hormone-independent) were used. A hormone-resistant MCF7/hydroxytamoxifen (HT) subline was obtained by long-term cultivation of the MCF7 line with hydroxytamoxifen. Antiproliferative activity was assessed by the MTT test; the expression of signaling pathway proteins was evaluated by immunoblotting analysis.

Findings/Results

We evaluated the antiproliferative activity of lignans in breast cancer cells with different levels of hormone dependence and determined the relevant IC50 values. Honokiol was chosen as the leading compound, and its IC50 ranged from 12 to 20 μM, whereas for other tested lignans, the IC50 exceeded 50 μM. The accumulation of cleaved PARP and a decrease in the expression of Bcl-2 and ERα in MCF7/HT were induced following the combination of honokiol with metformin.

Conclusions and implications

Honokiol demonstrated significant antiproliferative activity against both hormone-dependent breast cancer cells and lines with primary and acquired hormone resistance. The combination of honokiol with metformin is considered an effective approach to induce death in hormone-resistant cells. Honokiol is of interest as a natural compound with antiproliferative activity against breast cancers, including resistant tumors.

A systematic review on botany, ethnopharmacology, quality control, phytochemistry, pharmacology and toxicity of Arctium lappa L. fruit

ETHNOPHARMACOLOGICAL RELEVANCE

Arctium lappa L., is a biennial plant that grows around the Eurasia. Many parts of Arctium lappa L. (roots, leaves and fruits, etc.) are medically used in different countries. Arctium lappa L. fruit, also called Arctii Fructus, is traditionally applied to dispel wind-heat, ventilate lung to promote eruption, remove toxicity substance and relieve sore throat.

THE AIM OF THE REVIEW

The review aims to integrate the botany, ethnopharmacology, quality control, phytochemistry, pharmacology, derivatives and toxicity information of Arctii Fructus, so as to facilitate future research and explore the potential of Arctii Fructus as an agent for treating diseases.

MATERIALS AND METHODS

Related knowledge about Arctii Fructus were acquired from Science Direct, GeenMedical, PubMed, China National Knowledge Infrastructure (CNKI), Web of Science, Pharmacopoeia of the People's Republic of China, Doctoral and Master's thesis, ancient books, etc. RESULTS: Arctii Fructus as an herb used for medicine and food was pervasively distributed and applicated around the world. It was traditionally used to treat anemopyretic cold, dyspnea and cough, sore throat, etc. To date, more than 200 compounds have been isolated and identified from Arctii Fructus. It contained lignans, phenolic acids and fatty acids, terpenoids, volatile oils and others. Lignans, especially arctigenin and arctiin, had the extensive pharmacological effects such as anti-cancer, antiviral, anti-inflammatory activities. The ester derivatives of arctigenin had the anti-cancer, anti-Alzheimer's disease and immunity enhancing effects. Although Arctii Fructus extract had no toxicity, arctigenin was toxic at a certain dose. The alleviating effects of Arctii Fructus on chronic inflammation and ageing have been demonstrated by clinical studies.

CONCLUSION

Arctii Fructus is regarded as a worthy herb with many chemical components and various pharmacological effects. Several traditional applications have been supported by modern pharmacological research. However, their action mechanisms need to be further studied. Although many chemical components were isolated from Arctii Fructus, the current research mainly focused on lignans, especially arctiin and arctigenin. Therefore, it is very important to deeply clarify the pharmacological activities and action mechanism of the compounds and make full medicinal use of the resources of Arctii Fructus.

Identification of potential inhibitory analogs of metastasis tumor antigens (MTAs) using bioactive compounds: revealing therapeutic option to prevent malignancy

The deeper understanding of metastasis phenomenon and detection of drug targets could be a potential approach to minimize cancer mortality. In this study, attempts were taken to unmask novel therapeutics to prevent metastasis and cancer progression. Initially, we explored the physiochemical, structural and functional insights of three metastasis tumor antigens (MTAs) and evaluated some plant-based bioactive compounds as potent MTA inhibitors. From 50 plant metabolites screened, isoflavone, gingerol, citronellal and asiatic acid showed maximum binding affinity with all three MTA proteins. The ADME analysis detected no undesirable toxicity that could reduce the drug likeness properties of top plant metabolites. Moreover, molecular dynamics studies revealed that the complexes were stable and showed minimum fluctuation at molecular level. We further performed ligand-based virtual screening to identify similar drug molecules using a large collection of 376,342 compounds from DrugBank. The results suggested that several structural analogs (e.g., tramadol, nabumetone, DGLA and hydrocortisone) may act as agonist to block the MTA proteins and inhibit cancer progression at early stage. The study could be useful to develop effective medications against cancer metastasis in future. Due to encouraging results, we highly recommend further in vitro and in vivo trials for the experimental validation of the findings.

Matairesinol Induces Mitochondrial Dysfunction and Exerts Synergistic Anticancer Effects with 5-Fluorouracil in Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive types of cancer and exhibits a devastating 5-year survival rate. The most recent procedure for the treatment of PDAC is a combination of several conventional chemotherapeutic agents, termed FOLFIRINOX, that includes irinotecan, leucovorin, oxaliplatin, and 5-fluorouracil (5-FU). However, ongoing treatment using these agents is challenging due to their severe side effects and limitations on the range of patients available for PDAC. Therefore, safer and more innovative anticancer agents must be developed. The anticarcinoma activity of matairesinol that can be extracted from seagrass has been reported in various types of cancer, including prostate, breast, cervical, and pancreatic cancer. However, the molecular mechanism of effective anticancer activity of matairesinol against pancreatic cancer remains unclear. In the present study, we confirmed the inhibition of cell proliferation and progression induced by matairesinol in representative human pancreatic cancer cell lines (MIA PaCa-2 and PANC-1). Additionally, matairesinol triggers apoptosis and causes mitochondrial impairment as evidenced by the depolarization of the mitochondrial membrane, disruption of calcium, and suppression of cell migration and related intracellular signaling pathways. Finally, matairesinol exerts a synergistic effect with 5-FU, a standard anticancer agent for PDAC. These results demonstrate the therapeutic potential of matairesinol in the treatment of PDAC.

Chemotherapeutics activities of dietary phytoestrogens against prostate cancer: From observational to clinical studies

Prostate cancer remains one of the most frequent and deadliest malignancies in males, where the rate of disease progression is closely associated with the type of dietary intake, specifically Western-style diet. Indeed intake of the Asian diet, which contains abundant phytoestrogens, is inversely correlated with a higher risk of prostate cancer, suggesting a chemoprotective effect of phytoestrogen against cancer progression. Although the role of phytoestrogens in cancer treatment was well documented, their impact on prostate cancer is not well understood. Therefore, the present review discusses the possible chemopreventive effect of phytoestrogens, emphasizing their efficacy at the different stages of carcinogenesis. Furthermore, phytoestrogens provide a cytoprotective effect in conventional chemotherapy and enhance chemosensitivity to tumor cells, which have also been discussed. This compilation provides a solid basis for future research on phytoestrogens as a promising avenue for anticancer drug development and also recommends these beneficiary compounds in the daily diet to manage and prevent prostate cancer.

Phytochemical analysis of Daphne pontica L. stems with their pro-apoptotic properties against DU-145 and LNCaP prostate cancer cells

BACKGROUND

Daphne pontica is an endemic plant grown wild in the North part of Iran, with anticancer activities.

OBJECTIVES

This study aims to analyze the phytochemistry and screen the cytotoxic activity of new bioactive compounds against a panel of cancer cells, in addition to proapototic properties against prostate cancer cells.

METHOD

Purification procedure was done using repeated column chromatographies by MPLC and HPLC systems. The structures were elucidated by the NMR and exact mass spectroscopy, stereochemistry by NOESY, and absolute configuration by electronic circular dichroism (ECD) spectra. Cytotoxicity was done against DU 145, LNCaP, HeLa, MCF-7, and MDA-MB 231 cells by standard MTT assay. An annexin V/PI assay was performed to measure the type of death following treatment with these compounds for 48 h, followed by the caspase-3 activity test.

RESULTS

In this study, one new dilignan named lignopontin A (9), in addition to 13 known compounds including two phenolic acids (3, 5), one flavanone (6), one bis flavonoid (1), one cumarin glycoside (2), one mono (4) and two dicumarins (10, 11), two lignans (7, 8), and three daphnane diterpenoids (12-14) were isolated for the first time from D. pontica stems. Complete spectral data of compound 12, named as 6,7α-epoxy-5β-hydroxy-9,13,14-ortho-(4,2E)-pentadeca-2,4-diene-1-yl)-resiniferonol, and compound 14, named as 6,7α-epoxy-5β-hydroxy-9,3,14-ortho-(2,4E)-pentadeca-2,4-di-1-yl)-resiniferonol-12β-yl-acetate are reported for the first time. In the MTT assay of newly described compounds against a panel of cancer cells, compounds 9, 12, and 14 possessed moderate to potent cytotoxicity against prostate, breast, and cervical cancer cells in a dose-dependent manner. Flow cytometry analysis against prostate cancer cells indicated that the cytotoxicity of compounds 12 and 14 was due to their ability to induce apoptosis. In the case of compound 9, in Du 145 cells, cell death was mainly through apoptosis. In contrast, LNCaP cells showed both apoptosis and necrotic cell death, predominated by necrosis at the higher concentrations. Caspase-3 activity confirmed apoptosis observed in these compounds through the caspase pathway in prostate cancer cells.

CONCLUSION

D. pontica is a new source of dimeric phenolic compounds, including bisflavonoids, phenylpropanoid-cumarin adduct, and dilignans, as well as daphnane diterpenoids with resiniferonol core with long-chain orthoester moieties. In cytotoxicity screening, compounds 9, 12, and 14 inhibited the growth of DU-145 and LNCaP cells in a dose-dependent manner with IC₅₀ varied from 0.9 - 27.3 and 25.2 - 87.4 μM, respectively. Among them, 9 exhibited selective growth inhibition against DU 145 treated cells. LNCaP cells demonstrated the highest sensitivity to treatment with compound 12.

Phytochemical, Antiplasmodial, Cytotoxic and Antimicrobial Evaluation of a Southeast Brazilian Brown Propolis Produced by Apis mellifera Bees

Seven phenolic compounds (ferulic acid, caffeic acid, 4-methoxycinnamic acid, 3,4-dimethoxycinnamic acid, 3-hydroxy-4-methoxybenzaldehyde, 3-methoxy-4-hydroxypropiophenone and 1-O,2-O-digalloyl-6-O-trans-p-coumaroyl-β-D-glucopyranoside), a flavanonol (7-O-methylaromadendrin), two lignans (pinoresinol and matairesinol) and six diterpenic acids/alcohol (19-acetoxy-13-hydroxyabda-8(17),14-diene, totarol, 7-oxodehydroabietic acid, dehydroabietic acid, communic acid and isopimaric acid) were isolated from the hydroalcoholic extract of a Brazilian Brown Propolis and characterized by NMR spectral data analysis. The volatile fraction of brown propolis was characterized by CG-MS, composed mainly of monoterpenes and sesquiterpenes, being the major α-pinene (18.4 %) and β-pinene (10.3 %). This propolis chemical profile indicates that Pinus spp., Eucalyptus spp. and Araucaria angustifolia might be its primary plants source. The brown propolis displayed significant activity against Plasmodium falciparum D6 and W2 strains with IC₅₀ of 5.3 and 9.7 μg/mL, respectively. The volatile fraction was also active with IC₅₀ of 22.5 and 41.8 μg/mL, respectively. Among the compounds, 1-O,2-O-digalloyl-6-O-trans-p-coumaroyl-β-D-glucopyranoside showed IC₅₀ of 3.1 and 1.0 μg/mL against D6 and W2 strains, respectively, while communic acid showed an IC₅₀ of 4.0 μg/mL against W2 strain. Cytotoxicity was determined on four tumor cell lines (SK-MEL, KB, BT-549, and SK-OV-3) and two normal renal cell lines (LLC-PK1 and VERO). Matairesinol, 7-O-methylaromadendrin, and isopimaric acid showed an IC₅₀ range of 1.8-0.78 μg/mL, 7.3-100 μg/mL, and 17-18 μg/mL, respectively, against the tumor cell lines but they were not cytotoxic against normal cell lines. The crude extract of brown propolis displayed antimicrobial activity against C. neoformans, methicillin-resistant Staphylococcus aureus, and P. aeruginosa at 29.9 μg/mL, 178.9 μg/mL, and 160.7 μg/mL, respectively. The volatile fraction inhibited the growth of C. neoformans at 53.0 μg/mL. The compounds 3-hydroxy-4-methoxybenzaldehyde, 3-methoxy-4-hydroxypropiophenone and 7-oxodehydroabietic acid were active against C. neoformans, and caffeic and communic acids were active against methicillin-resistant Staphylococcus aureus.

Matairesinol, an active constituent of HC9 polyherbal formulation, exhibits HDAC8 inhibitory and anticancer activity

Histone deacetylase 8 (HDAC8) has emerged as a promising drug target for cancer therapeutics development. HDAC8 has been reported to regulate cancer cell proliferation, invasion and promote metastasis through modulation of cell cycle associated proteins. Of late, phytocompounds have been demonstrated to exhibit anticancer and anti-HDAC8 activity. Here, we have shown the HDAC8 inhibitory potential of an active phytocompound from HC9 (herbal composition-9), a polyherbal anticancer formulation based on the traditional Ayurvedic drug, Stanya Shodhan Kashaya. HC9 was recently reported to exhibit anticancer activity against breast cancer cells through induction of cell cycle arrest, decrease in migration and invasion as well as regulation of inflammation and chromatin modulators. In silico studies such as molecular docking, molecular dynamics (MD) simulation and binding free energy analyses showed greater binding energy values and interaction stability of MA with HDAC8 compared to other phytocompounds of HC9. Interestingly, in vitro validation confirmed the anti-HDAC8 activity of MA. Further, in vitro studies showed that MA significantly decreased the viability of breast and prostate cancer cell lines, thereby confirming its anticancer potential.

Phytochemicals from Ayurvedic plants as potential medicaments for ovarian cancer: an in silico analysis

Ovarian cancer is one of the highly prominent gynecological malignancies after breast cancer. Although myriad literature is available, there is no specific biomarker available for the personalized treatment strategy. The unavailability of effective drug therapy for ovarian cancer calls for an urgent push in its development from the multidisciplinary scientific community. Indian Ayurvedic medicine pharmacology is widely appreciated and accepted for its immense healthcare benefits. Bioinformatics and cheminformatics approaches can be effectively used to screen phytochemicals present in the Indian Ayurvedic plants against ovarian cancer target receptors. Recent studies discern that POTE, a cancer-testis antigen (CTA) family, plays a crucial role in the proliferation and progression of cancers including ovarian cancer. Specifically, POTEE paralog has been observed to be hypermethylated in ovarian cancer. This study undertakes an in silico analysis of Indian Ayurvedic plants for their anticancer efficacy against ovarian cancer proliferation target receptor POTEE. Structures of 100 phytochemicals from 11 Ayurvedic plants were screened with ADME criteria, and qualified phytochemicals were subjected to molecular docking and interaction analysis. Only 6 phytochemicals having a high affinity to the target receptor (POTEE) were then subjected to an all-atom replica exchange molecular dynamics simulation for 50 ns. Binding affinities of 6 phytochemicals cedeodarin, deodarin, hematoxylin, matairesinol, quercetin, and taxifolin with POTEE were -8.1, -7.7, -7.7, -7.9, -8.0, and - 7.7 kcal/mol, respectively, and their RMSD were recorded as zero. This study concludes that phytochemicals present in Indian Ayurvedic plants namely Cedrus deodara and Asparagus racemosus possess inhibitory effects against ovarian cancer proliferation receptor POTEE.

HPLC phenolic profile and induction of apoptosis by Linum usitatissimum extract in LNCaP cells by caspase3 and Bax pathways

Linum usitatissimum is a candidate as a remedy to treat prostate problems in some folklore medicines. In this study, we have reported the phenolic and flavonoid constituents, antioxidant activity, and potential of the plant extract against prostate cancer cells. The phenolic and flavonoid compound profile of the extract were established using HPLC analysis. While the total phenolic and flavonoid content (TPC and TFC) were analyzed using classic methods. The antioxidant activity of the extract was also evaluated. MTT assay and flow cytometry technique was used to evaluate antiproliferation activity and induction apoptosis of the plant extract on prostate cancer cells of LNCaP. We also evaluated the gene expression of Bax and caspase-3 using the real-time qPCR assay. HPLC result revealed that L. usitatissimum extract (LUE) was rich in phenolic acids such as gallic, ferulic, and vanillic acid with the amount of 3.56, 2.12, 1.24 μg/g extract respectively. 383.4 mg GAE/g and 47.1 mgRuE/g were calculated for total phenolic and flavonoid content. LUE exhibited radical scavenging activity with IC50 = 19.3 ± 1.1 µg/mL. LUE chelated ferrous ions with IC50 = 121.1 ± 1.3 µg/mL. LUE showed anti-proliferative activity on LNCaP cells with the IC50 values of 8.3, 6.3, and 5.4 μg/mL after 24, 48, and 72 h treatment. LUE also increased cell mortality by inducing apoptosis (15.3-29.8%). The real-time qPCR results exhibited an increase in gene expression of Bax and caspase-3. Our in vitro study demonstrates that L. usitatissimum can be considered as an effective agent to inhibit the growth and invasion the human prostate cancer cells.

Inhibition of CSF1R and AKT by (±)-kusunokinin hinders breast cancer cell proliferation

Kusunokinin, a lignan compound, inhibits cancer cell proliferation and induces apoptosis; however, the role of kusunokinin is not fully understood. Here, we aimed to identify a target protein of (-)-kusunokinin and determine the protein levels of its downstream molecules. We found that (-)-kusunokinin bound 5 possible target proteins, including CSF1R, MMP-12, HSP90-α, CyclinB1 and MEK1 with ΔG_bind less than -10.40 kcal/mol. MD simulation indicated (-)-kusunokinin and pexidartinib (P31, a specific CSF1R binding compound) shared some extents of functional similarity in which (-)-kusunokinin bound CSF1R at the juxtamembrane (JM) region with aromatic amino acids similar to pexidartinib using π-π interaction, as well as hydrogen bond. Both P31 and (-)-kusunokinin moved into the same CSF1R region and W7 was a mutual key residue. However, the P31 binding site differed from the (-)-kusunokinin binding site. For in vitro study, the synthetic (±)-kusunokinin exhibited stronger cytotoxicity than picropodophyllotoxin, silibinin and etoposide on MCF-7 cells and represented less toxicity than picropodophyllotoxin and doxorubicin on L-929 and MCF-12A cells. Knocking down CSF1R using a specific siRNA combination with (±)-kusunokinin demonstrated levels of cell proliferation proteins slightly higher than siRNA-CSF1R treatment. However, siRNA-CSF1R combination with P31 represented the number of cell viability and cell proliferation proteins, like in the control groups (Lipofectamine and siRNA-Luciferase). Moreover, (±)-kusunokinin suppressed CSF1R and its downstream proteins, including AKT, CyclinD1 and CDK1. Meanwhile, both P31 and siRNA-CSF1R dramatically suppressed CSF1R, MEK1, AKT, ERK, CyclinB1, CyclinD1 and CDK1. Our overall results indicate that the mechanism of (±)-kusunokinin differed fairly from P31. We have concluded that (±)-kusunokinin inhibited breast cancer cell proliferation partially through the binding and suppression of CSF1R, which consequently affected AKT and its downstream molecules.

Evaluation of the anti-cancer potential of Cedrus deodara total lignans by inducing apoptosis of A549 cells

BACKGROUND

Cedrus deodara (Roxb.) Loud (normally called as deodar), one out of four species in the genus Cedrus, exhibits widely biological activities. The Cedrus deodara total lignans from the pine needles (CTL) were extracted. The aim of the study was to investigate the anticancer potential of the CTL on A549 cell line.

METHODS

We extracted the CTL by ethanol and assessed the cytotoxicity by CCK-8 method. Cell cycle and apoptosis were detected by a FACS Verse Calibur flow cytometry.

RESULTS

The CTL were extracted by means of ethanol hot refluxing and the content of total lignans in CTL was about 55.77%. By the CCK-8 assays, CTL inhibited the growth of A549 cells in a dose-dependent fashion, with the IC50 values of 39.82 ± 1.74 μg/mL. CTL also inhibited the growth to a less extent in HeLa, HepG2, MKN28 and HT-29 cells.

CONCLUSION

At low doses, the CTL effectively inhibited the growth of A549 cells. By comparison of IC50 values, we found that A549 cells might be more sensitive to the treatment with CTL. In addition, CTL were also able to increase the population of A549 cells in G2/M phase and the percentage of apoptotic A549 cells. CTL may have therapeutic potential in lung adenocarcinoma cancer by regulating cell cycle and apoptosis.

Flaxseed Lignans as Important Dietary Polyphenols for Cancer Prevention and Treatment: Chemistry, Pharmacokinetics, and Molecular Targets

Cancer causes considerable morbidity and mortality across the world. Socioeconomic, environmental, and lifestyle factors contribute to the increasing cancer prevalence, bespeaking a need for effective prevention and treatment strategies. Phytochemicals like plant polyphenols are generally considered to have anticancer, anti-inflammatory, antiviral, antimicrobial, and immunomodulatory effects, which explain their promotion for human health. The past several decades have contributed to a growing evidence base in the literature that demonstrate ability of polyphenols to modulate multiple targets of carcinogenesis linking models of cancer characteristics (i.e., hallmarks and nutraceutical-based targeting of cancer) via direct or indirect interaction or modulation of cellular and molecular targets. This evidence is particularly relevant for the lignans, an ubiquitous, important class of dietary polyphenols present in high levels in food sources such as flaxseed. Literature evidence on lignans suggests potential benefit in cancer prevention and treatment. This review summarizes the relevant chemical and pharmacokinetic properties of dietary polyphenols and specifically focuses on the biological targets of flaxseed lignans. The consolidation of the considerable body of data on the diverse targets of the lignans will aid continued research into their potential for use in combination with other cancer chemotherapies, utilizing flaxseed lignan-enriched natural products.

Xanthohumol increases death receptor 5 expression and enhances apoptosis with the TNF-related apoptosis-inducing ligand in neuroblastoma cell lines

High-risk neuroblastoma (NB) is lethal childhood cancer. Published data including ours have reported the anti-proliferative effect of Xanthohumol (XN), a prenylated chalcone, in various cancer types suggesting that XN could be a useful small molecule compound against cancer. The TNF-Related Apoptosis-Inducing Ligand (TRAIL) is an endogenous ligand that is expressed in various immune cells. TRAIL mediates apoptosis through binding of transmembrane receptors, death receptor 4 (DR4) and/or death receptor 5 (DR5). Cancer cells are frequently resistant to TRAIL-mediated apoptosis, and the cause of this may be decreased expression of death receptors. This study aimed to identify combination therapies that exploit XN for NB. First, the effect of XN on cellular proliferation in human NB cell lines NGP, SH-SY-5Y, and SK-N-AS were determined via MTT assay, colony forming assay, and real-time live cell imaging confluency. XN treatment causes a statistically significant decrease in the viability of NB cells with IC50 values of approximately 12 μM for all three cell lines. Inhibition of cell proliferation via apoptosis was evidenced by an increase in pro-apoptotic markers (cleaved PARP, cleaved caspase-3/-7, and Bax) and a decrease in an anti-apoptotic marker, Bcl-2. Importantly, XN treatment inhibited PI3K/Akt pathway and associated with increased expression of DR5 by both mRNA and protein levels. Furthermore, a statistically significant synergistic reduction was observed following combination treatment (50%) compared to either TRAIL (5%) or XN (15%) alone in SK-N-AS cells. Therefore, this study shows XN treatment reduces NB cell growth via apoptosis in a dose-dependent manner, and enhanced growth reduction was observed in combination with TRAIL. This is the first study to demonstrate that XN alters the expression of DR5 as well as the synergistic effect of XN on TRAIL in NB and provides a strong rationale for further preclinical analysis.

Flaxseed Lignans Enhance the Cytotoxicity of Chemotherapeutic Agents against Breast Cancer Cell Lines MDA-MB-231 and SKBR3

Systemic cytotoxic chemotherapy remains the mainstay of metastatic breast cancer; however, prognosis and overall survival is unfavorable due to inadequate treatment response and/or unacceptable toxicity. Natural compounds and their active metabolites receive increasing attention as possible adjuvant therapy with cancer chemotherapeutics to improve treatment response, survival rates, and quality of life of breast cancer patients. This study investigated the combination of flaxseed lignans (Secoisolariciresinol and Enterolactone) with classic chemotherapeutic agents (Docetaxel, Doxorubicin, and Carboplatin) with different mechanisms of action to determine whether flaxseed lignans could enhance the cytotoxic effect of such drugs in the metastatic breast cancer cell lines, SKBR3 and MDA-MB-231. The experimental data suggests that flaxseed lignans significantly enhanced the ability of chemotherapeutic agents to cause cytotoxicity in SKBR3 and MDA-MB-231 breast cancer cells. A three compound combination study found that enterolactone and metformin together in combination with relatively low concentrations of chemotherapeutic drugs were able to significantly decrease cancer cell viability, compared to low concentrations of the individual chemotherapeutic drug alone. Our in vitro evaluation suggests a future direction in improving chemotherapeutic efficacy in breast cancer by adjuvant therapy with the flaxseed lignans.

Restoring TRAIL Induced Apoptosis Using Naturopathy. Hercules Joins Hand with Nature to Triumph Over Lernaean Hydra

Cancer is a multifaceted disease. Our deepened knowledge about genetic and biological mechanisms of cancer cells presents an opportunity to explore the inter-individual differences in the body’s ability to metabolize and respond to different nutrients. It is becoming progressively more understandable that the deregulation of several signaling pathways and the alterations in apoptotic response are some of the major determinants that underpin carcinogenesis. Tumor necrosis factor-Related Apoptosis-Inducing Ligand (TRAIL)-mediated signaling has gained a remarkable appreciation because of its ability to selectively induce apoptosis in cancer cells leaving normal cells intact. However, technological advances have started to shed light on underlying mechanisms of resistance against TRAIL-induced apoptosis in cancer cells. The impairment of TRAIL-mediated apoptosis includes various factors ranging from the loss or down regulation of TRAIL receptors or pro-apoptotic proteins to the up regulation of anti-apoptotic proteins. Intriguingly to mention that there is an ever-increasing number of natural herbal extracts (phytometabolites), which have been explored to date for their potential action in restoring apoptosis TRAIL-mediated in cancer cells. In this review, we will highlight the progress in understanding the mechanisms opted by phenolic compounds in overcoming TRAIL resistance.

Chronic over-nutrition and dysregulation of GSK3 in diseases

Loss of cellular response to hormonal regulation in maintaining metabolic homeostasis is common in the process of aging. Chronic over-nutrition may render cells insensitive to such a hormonal regulation owing to overstimulation of certain signaling pathways, thus accelerating aging and causing diseases. The glycogen synthase kinase 3 (GSK3) plays a pivotal role in relaying various extracellular and intracellular regulatory signals critical to cell growth, survival, regeneration, or death. The main signaling pathway regulating GSK3 activity through serine-phosphorylation is the phosphoinositide 3-kinase (PI3K)/phosphoinositide-dependent kinase-1 (PDK1)/Akt relay that catalyzes serine-phosphorylation and thus inactivation of GSK3. In addition, perilipin 2 (PLIN2) has recently been shown to regulate GSK3 activation through direct association with GSK3. This review summarizes current understanding on environmental and nutritional factors contributing to GSK3 regulation (or dysregulation) through the PI3K/PDK1/Akt/GSK3 axis, and highlights the newly discovered role that PLIN2 plays in regulating GSK3 activity and GSK3 downstream pathways.

Xanthohumol inhibits the extracellular signal regulated kinase (ERK) signalling pathway and suppresses cell growth of lung adenocarcinoma cells

Aberrant activation of the Ras/MEK/ERK signaling pathway has been frequently observed in non-small-cell lung carcinoma (NSCLC) and its important role in cancer progression and malignant transformation has been documented. Hence, the ERK1/2 kinase cascade becomes a potential molecular target in cancer treatment. Xanthohumol (XN, a prenylated chalcone derived from hope cones) is known to possess a broad spectrum of chemopreventive and anticancer activities. In our studies, the MTT and BrdU assays revealed that XN demonstrated greater antiproliferative activity against A549 lung adenocarcinoma cells than against the lung adenocarcinoma H1563 cell line. We observed that XN was able to suppress the activities of ERK1/2 and p90RSK kinases, followed by inhibition of phosphorylation and activation of the CREB protein. Additionally, the XN treatment of the cancer cells caused upregulation of key cell cycle regulators p53 and p21 as well as downregulation of cyclin D1. As a result, the cytotoxic effect of XN was attributed to the cell cycle arrest at G1 phase and induction of apoptosis indicated by increased caspase-3 activity. Thus, XN might be a promising anticancer drug candidate against lung carcinomas.

2'-Hydroxy-4-methylsulfonylchalcone enhances TRAIL-induced apoptosis in prostate cancer cells

Prostate cancer is the most common malignant cancer in men and the second leading cause of cancer deaths. Previously, we have shown that 2'-hydroxy-4-methylsulfonylchalcone (RG003) induced apoptosis in prostate cancer cell lines PC-3 and DU145. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent, some cancer cells are resistant to TRAIL treatment. PC-3 and LNCaP prostatic cancer cell lines have been reported to be resistant to TRAIL-induced apoptosis. Here, we show for the first time that RG003 overcomes TRAIL resistance in prostate cancer cells. RG003 can enhance TRAIL-induced apoptosis through DR5 upregulation and downregulation of Bcl-2, PI3K/Akt, NF-κB, and cyclooxygenase-2 (COX-2) survival pathways. When used in combined treatment, RG003 and TRAIL amplified TRAIL-induced activation of apoptosis effectors and particularly activation of caspase-8 and the executioner caspase-3, leading to increased poly-ADP-ribose polymerase cleavage and DNA fragmentation in prostate cancer cells. Furthermore, we showed that RG003 reduced COX-2 expression in cells. Previously, we showed that COX-2 was involved in resistance to an apoptosis mechanism; then, its inhibition by RG003 could render cells more sensitive to TRAIL treatment. We showed that nuclear factor-κB activation was inhibited after RG003 treatment. This inhibition was correlated with reduction in COX-2 expression and induction of apoptosis. Overall, we conclude, for the first time, that RG003 can enhance TRAIL-induced apoptosis in human prostate cancer cells. The significance of our in-vitro study with RG003 and TRAIL combined is very encouraging, suggesting the relevance of testing this combined treatment in xenograft animal models.

Akt inhibitors in cancer treatment: The long journey from drug discovery to clinical use (Review)

Targeted cancer therapies are used to inhibit the growth, progression, and metastasis of the tumor by interfering with specific molecular targets and are currently the focus of anticancer drug development. Protein kinase B, also known as Akt, plays a central role in many types of cancer and has been validated as a therapeutic target nearly two decades ago. This review summarizes the intracellular functions of Akt as a pivotal point of converging signaling pathways involved in cell growth, proliferation, apoptotis and neo‑angiogenesis, and focuses on the drug design strategies to develop potent anticancer agents targeting Akt. The discovery process of Akt inhibitors has evolved from adenosine triphosphate (ATP)‑competitive agents to alternative approaches employing allosteric sites in order to overcome the high degree of structural similarity between Akt isoforms in the catalytic domain, and considerable structural analogy to the AGC kinase family. This process has led to the discovery of inhibitors with greater specificity, reduced side-effects and lower toxicity. A second generation of Akt has inhibitors emerged by incorporating a chemically reactive Michael acceptor template to target the nucleophile cysteines in the catalytic activation loop. The review outlines the development of several promising drug candidates emphasizing the importance of each chemical scaffold. We explore the pipeline of Akt inhibitors and their preclinical and clinical examination status, presenting the potential clinical application of these agents as a monotherapy or in combination with ionizing radiation, other targeted therapies, or chemotherapy.

Anticancer effect of ethanol Lycium barbarum (Goji berry) extract on human breast cancer T47D cell line

The anticancer activity of ethanol extract isolated from Goji berry (EEGB) on T47D human breast cancer cell line has been reported. Cell viability and cell proliferation were examined with the use of BrdU, MTT and NR methods. Induction of apoptosis was assessed by propidium iodide and Hoechst 33342 staining. Expression of genes involved in cell proliferation, apoptosis, cell cycle control and regulation of transcription was estimated using Western blotting analysis. EEGB inhibited the proliferation of breast cancer cells in a time-, and dose-dependent manner. The study confirmed the lack of EEGB cytotoxic activity to normal human skin fibroblasts. Western blot analysis demonstrated an increase in pro-apoptotic and a decrease in anti-apoptotic proteins' expression in cells treated with the extract. Anticancer activity and lack of toxicity against normal cells indicate a chemopreventive potential of Goji berries in breast cancer treatment.

A novel inactivating mutation of the LH/chorionic gonadotrophin receptor with impaired membrane trafficking leading to Leydig cell hypoplasia type 1

OBJECTIVE

The LH/chorionic gonadotrophin receptor (LHCGR) is a G protein-coupled receptor (GPCR) that plays a central role in male sexual differentiation, regulation of ovarian follicular maturation, ovulation and maintenance of corpus luteum and pregnancy, as well as maintenance of testicular testosterone production. Mutations in the LHCGR gene are very rare. The aim of this work was to study the clinical and molecular characteristics of a rare familial LHCGR mutation.

METHODS

Five affected members of a family, including a phenotypically female, but genotypically male (46,XY), patient with Leydig cell hypoplasia type 1 and four genotypically female siblings with reproductive abnormalities, were studied genetically. Cell trafficking studies as well as signalling studies of mutated receptor were performed.

RESULTS

The five affected patients were all homozygous for a novel mutation in the LHCGR gene, a deletion of guanine in position 1850 (1850delG). This resulted in a frameshift affecting most of the C-terminal intracellular domain. In vitro studies demonstrated that the 1850delG receptor was completely incapable of transit to the cell membrane, becoming trapped within the endoplasmic reticulum. This could not be rescued by small-molecule agonist treatment or stimulated intracellularly by co-expression of a yoked human chorionic gonadotrophin.

CONCLUSIONS

This novel LHCGR mutation leads to complete inactivation of the LHCGR receptor due to trafficking and signalling abnormalities, which improves our understanding of the impact of the affected structural domain on receptor trafficking and function.

Cyclin-dependent kinase 5 acts as a critical determinant of AKT-dependent proliferation and regulates differential gene expression by the androgen receptor in prostate cancer cells

CDK5 acts as a signaling hub in prostate cancer cells by controlling androgen responses through AR stabilization and specific gene targeting, maintaining and accelerating cell proliferation through activation of the oncogenic AKT kinase, and releasing cell cycle breaks in a variety of prostate cancer cell lines.

Contrary to cell cycle–associated cyclin-dependent kinases, CDK5 is best known for its regulation of signaling processes in differentiated cells and its destructive activation in Alzheimer's disease. Recently, CDK5 has been implicated in a number of different cancers, but how it is able to stimulate cancer-related signaling pathways remains enigmatic. Our goal was to study the cancer-promoting mechanisms of CDK5 in prostate cancer. We observed that CDK5 is necessary for proliferation of several prostate cancer cell lines. Correspondingly, there was considerable growth promotion when CDK5 was overexpressed. When examining the reasons for the altered proliferation effects, we observed that CDK5 phosphorylates S308 on the androgen receptor (AR), resulting in its stabilization and differential expression of AR target genes including several growth-priming transcription factors. However, the amplified cell growth was found to be separated from AR signaling, further corroborated by CDK5-depdent proliferation of AR null cells. Instead, we found that the key growth-promoting effect was due to specific CDK5-mediated AKT activation. Down-regulation of CDK5 repressed AKT phosphorylation by altering its intracellular localization, immediately followed by prominent cell cycle inhibition. Taken together, these results suggest that CDK5 acts as a crucial signaling hub in prostate cancer cells by controlling androgen responses through AR, maintaining and accelerating cell proliferation through AKT activation, and releasing cell cycle breaks.

Natural lignans from Arctium lappa modulate P-glycoprotein efflux function in multidrug resistant cancer cells

Arctium lappa is a well-known traditional medicinal plant in China (TCM) and Europe that has been used for thousands of years to treat arthritis, baldness or cancer. The plant produces lignans as secondary metabolites which have a wide range of bioactivities. Yet, their ability to reverse multidrug resistance (MDR) in cancer cells has not been explored. In this study, we isolated six lignans from A. lappa seeds, namely arctigenin, matairesinol, arctiin, (iso)lappaol A, lappaol C, and lappaol F. The MDR reversal potential of the isolated lignans and the underlying mechanism of action were studied using two MDR cancer cell lines, CaCo2 and CEM/ADR 5000 which overexpress P-gp and other ABC transporters. In two-drug combinations of lignans with the cytotoxic doxorubicin, all lignans exhibited synergistic effects in CaCo2 cells and matairesinol, arctiin, lappaol C and lappaol F display synergistic activity in CEM/ADR 5000 cells. Additionally, in three-drug combinations of lignans with the saponin digitonin and doxorubicin MDR reversal activity was even stronger enhanced. The lignans can increase the retention of the P-gp substrate rhodamine 123 in CEM/ADR 5000 cells, indicating that lignans can inhibit the activity of P-gp. Our study provides a first insight into the potential chemosensitizing activity of a series of natural lignans, which might be candidates for developing novel adjuvant anticancer agents.

Novel Lignan and stilbenoid mixture shows anticarcinogenic efficacy in preclinical PC-3M-luc2 prostate cancer model

Prostate cancer is the most common cancer of men in the Western world, and novel approaches for prostate cancer risk reduction are needed. Plant-derived phenolic compounds attenuate prostate cancer growth in preclinical models by several mechanisms, which is in line with epidemiological findings suggesting that consumption of plant-based diets is associated with low risk of prostate cancer. The objective of this study was to assess the effects of a novel lignan-stilbenoid mixture in PC-3M-luc2 human prostate cancer cells in vitro and in orthotopic xenografts. Lignan and stilbenoid –rich extract was obtained from Scots pine (Pinus sylvestris) knots. Pine knot extract as well as stilbenoids (methyl pinosylvin and pinosylvin), and lignans (matairesinol and nortrachelogenin) present in pine knot extract showed antiproliferative and proapoptotic efficacy at ≥40 μM concentration in vitro. Furthermore, pine knot extract derived stilbenoids enhanced tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced apoptosis already at ≥10 μM concentrations. In orthotopic PC-3M-luc2 xenograft bearing immunocompromized mice, three-week peroral exposure to pine knot extract (52 mg of lignans and stilbenoids per kg of body weight) was well tolerated and showed anti-tumorigenic efficacy, demonstrated by multivariate analysis combining essential markers of tumor growth (i.e. tumor volume, vascularization, and cell proliferation). Methyl pinosylvin, pinosylvin, matairesinol, nortrachelogenin, as well as resveratrol, a metabolite of pinosylvin, were detected in serum at total concentration of 7−73 μM, confirming the bioavailability of pine knot extract derived lignans and stilbenoids. In summary, our data indicates that pine knot extract is a novel and cost-effective source of resveratrol, methyl pinosylvin and other bioactive lignans and stilbenoids. Pine knot extract shows anticarcinogenic efficacy in preclinical prostate cancer model, and our in vitro data suggests that compounds derived from the extract may have potential as novel chemosensitizers to TRAIL. These findings promote further research on health-related applications of wood biochemicals.

Pinoresinol inhibits proliferation and induces differentiation on human HL60 leukemia cells

Pinoresinol (PIN), one of the simplest lignans, is the precursor of other dietary lignans that are present in whole-grain cereals, legumes, fruits, and other vegetables. Several experimental and epidemiological evidences suggest that lignans may prevent human cancer in different organs. In this study we investigated the chemopreventive properties of PIN on cell lines derived from different sites either expressing or not the functional tumor suppressor protein p53. It was found that PIN inhibited the proliferation of p53 wild type colon and prostate tumor cells (HCT116 and LNCaP) while in breast cells the inhibition of growth was observed only in p53 mutant cells (MDA-MB-231). A potent antiproliferative activity of PIN was also observed on p53 null cells HL60 (IC50% 8 μM), their multidrug resistant variant HL60R (IC50% 32 μM) and K562. On HL60 cells, PIN caused a block of cell cycle in the G0/G1 phase, induced a weak proapoptotic effect but it was a good trigger of differentiation (NBT reduction and CD11b expression). PIN caused an upregulation of the CDK inhibitor p21(WAF1/Cip1) both at mRNA and protein levels so suggesting that this could be a mechanism by which PIN reduced proliferation and induced differentiation on HL60 cells.

The antitumor lignan Nortrachelogenin sensitizes prostate cancer cells to TRAIL-induced cell death by inhibition of the Akt pathway and growth factor signaling

Prostate cancer cells frequently develop resistance toward androgen-deprivation and chemotherapy. To identify new approaches to treat androgen-dependent prostate cancer, we have performed a structure-activity analysis of lignan polyphenols for cancer cell specific sensitization to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a death ligand that has ability to induce tumor-specific cell death. In this study, we report that the lignan nortrachelogenin (NTG) is the most efficient of the 27 tested lignan compounds in sensitizing prostate cancer cells to TRAIL-induced apoptosis. Importantly, pretreatment with NTG does not sensitize a non-malignant prostate cell line to TRAIL-induced cell death. The structural comparison of lignans reveals that the dibenzylbutyrolactone skeleton is required for the apoptosis-sensitizing activity, while substitutions at the aromatic rings do not seem to play a critical role in this lignan function. Our study also characterizes the cellular effects and molecular mechanisms involved in NTG anticancer activity. We previously reported that specific lignans inhibit the Akt survival-signaling pathway in concert with TRAIL sensitization. While NTG is also shown to be a effective inhibitor of Akt signaling, in this study we further demonstrate that NTG potently inhibits tyrosine kinase (RTK) activation in response to growth factors, such as insulin and insulin-like growth factor I (IGF-I). Our results identify NTG as a novel agent for prostate cancer therapy with ability to inhibit Akt membrane localization and activity as well as the activation of growth factor receptors (GFRs), thereby efficiently synergizing with TRAIL exposure.

De Novo transcriptome assembly (NGS) of Curcuma longa L. rhizome reveals novel transcripts related to anticancer and antimalarial terpenoids

Herbal remedies are increasingly being recognised in recent years as alternative medicine for a number of diseases including cancer. Curcuma longa L., commonly known as turmeric is used as a culinary spice in India and in many Asian countries has been attributed to lower incidences of gastrointestinal cancers. Curcumin, a secondary metabolite isolated from the rhizomes of this plant has been shown to have significant anticancer properties, in addition to antimalarial and antioxidant effects. We sequenced the transcriptome of the rhizome of the 3 varieties of Curcuma longa L. using Illumina reversible dye terminator sequencing followed by de novo transcriptome assembly. Multiple databases were used to obtain a comprehensive annotation and the transcripts were functionally classified using GO, KOG and PlantCyc. Special emphasis was given for annotating the secondary metabolite pathways and terpenoid biosynthesis pathways. We report for the first time, the presence of transcripts related to biosynthetic pathways of several anti-cancer compounds like taxol, curcumin, and vinblastine in addition to anti-malarial compounds like artemisinin and acridone alkaloids, emphasizing turmeric's importance as a highly potent phytochemical. Our data not only provides molecular signatures for several terpenoids but also a comprehensive molecular resource for facilitating deeper insights into the transcriptome of C. longa.

TRAIL-activated EGFR by Cbl-b-regulated EGFR redistribution in lipid rafts antagonises TRAIL-induced apoptosis in gastric cancer cells

Most gastric cancer cells are resistant to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Since TRAIL resistance is associated with lipid rafts, in which both death receptors and epidermal growth factor receptors (EGFR) are enriched, our aim is to identify how lipid raft-regulated receptor redistribution influences the sensitivity of TRAIL in gastric cancer cells. In TRAIL-resistant gastric cancer cells, TRAIL did not induce effective death-inducing signalling complex (DISC) formation in lipid rafts, accompanied with EGFR translocation into lipid rafts, and activation of EGFR pathway. Knockdown of casitas B-lineage lymphoma-b (Cbl-b) enhanced TRAIL-induced apoptosis by promoting DISC formation in lipid rafts. However, knockdown of Cbl-b also enhanced EGFR translocation into lipid rafts and EGFR pathway activation induced by TRAIL. Either using inhibitors of EGFR or depletion of EGFR with small interfering RNA (siRNA) prevented EGFR pathway activation, and thus increased TRAIL-induced apoptosis, especially in Cbl-b knockdown clones. Taken together, TRAIL-induced EGFR activation through Cbl-b-regulated EGFR redistribution in lipid rafts antagonised TRAIL-induced apoptosis. The contribution of DISC formation and the inhibition of EGFR signal triggered in lipid rafts are both essential for increasing the sensitivity of gastric cancer cells to TRAIL.

Regulating TRAIL receptor-induced cell death at the membrane : a deadly discussion

The use of TRAIL/APO2L and monoclonal antibodies targeting TRAIL receptors for cancer therapy holds great promise, due to their ability to restore cancer cell sensitivity to apoptosis in association with conventional chemotherapeutic drugs in a large variety of tumors. TRAIL-induced cell death is tightly regulated right from the membrane and at the DISC (Death-Inducing Signaling Complex) level. The following patent and literature review aims to present and highlight recent findings of the deadly discussion that determines tumor cell fate upon TRAIL engagement.

TRAIL-mediated signaling in prostate, bladder and renal cancer

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a death receptor ligand that has the ability to preferentially initiate apoptosis in malignant cells with minimal toxicity to normal cells. TRAIL-based therapeutics, including recombinant TRAIL, TRAIL-receptor agonistic antibodies and TRAIL gene therapy, have now entered clinical trials. Although these therapeutics are promising, concerns regarding TRAIL resistance are causing research efforts to shift towards the identification of effective combination therapies. Small-molecule inhibitors, natural compounds, and drugs approved for treatment of diseases other than cancer have been shown to affect TRAIL receptors, antiapoptotic proteins and survival pathways in prostate, bladder and renal cell lines and in preclinical models. Changes in endogenous TRAIL and TRAIL receptor expression during the development of genitourinary malignancies and the way in which the expression pattern is affected by treatment are of great interest, and understanding the biological consequences of such changes will be important to maximize the potential of TRAIL-based therapeutics.

Assessment of information to substantiate a health claim on the prevention of prostate cancer by lignans

Lignans and their in vivo metabolites, especially enterolactone (ENL), have attracted substantial interest as potential chemopreventive agents for prostate cancer. Preclinical and clinical interventions performed with lignan-rich flaxseed that use surrogate biomarkers as endpoints suggest that lignans may attenuate prostate carcinogenesis in individuals with increased risk or with diagnosed cancer. No unequivocal prostate cancer risk reduction has been found for lignans in epidemiological studies, suggesting that lignan concentrations found in populations consuming a regular non-supplemented diet are not chemopreventive in prostate cancer. Presumably, the main obstacles in assessing the efficacy of food lignans is limited knowledge of the serum and tissue lignan concentrations required for the putative prevention. Further clinical studies performed with the purified compounds are required to substantiate a health claim.