Polyphenols isolated from Allium cepa L. induces apoptosis by suppressing IAP-1 through inhibiting PI3K/Akt signaling pathways in human leukemic cells

Cancer and Traditional Plant Knowledge, an Interesting Field to Explore: Data from the Catalan Linguistic Area

Cancer is the second cause of death in the world and is foreseen to be responsible for about 16 million deaths in 2040. Approximately, 60% of the drugs used to treat cancer are of natural origin. Besides the extensive use of some of these drugs in therapies, such as those derived from the genus Taxus, a significant number of plants have revealed themselves as useful against cancer in recent years. The field of ethnobotany focuses on documenting traditional knowledge associated with plants, constituting a starting point to uncover the potential of new plant-based drugs to treat or prevent, in this case, tumour diseases and side effects of chemotherapy and radiotherapy. From a series of extensive ethnobotanical prospections across the Catalan linguistic area (CLA), we have recorded uses for 41 taxa with antitumour effects. The two most quoted botanical families are Asteraceae and Ranunculaceae, and the most frequently reported species is Ranunculus parnassifolius, a high-mountain species, which is widely collected for this purpose. The reported species have been used to treat an important number of cancer types, focusing on preventive, palliative, and curative uses, as well as to deal with the side effects of conventional treatments. Comparing our results in CLA with previous data available in the most comprehensive databases of pharmacology and a review of cytotoxicity assays revealed that for the several species reported here, there was no previous evidence of traditional uses against cancer. Despite the need for further analyses to experimentally validate the information presented here, combining traditional uses and phylogenetically-informed strategies to phytochemical and pharmacological research would represent new avenues to establish more integrative approaches, hence improving the ability to select new candidate taxa in cancer research.

Recent advances in research on Allium plants: functional ingredients, physiological activities, and applications in agricultural and food sciences

Fruits and vegetables (FVs) have long been a major source of nutrients and dietary phytochemicals with outstanding physiological properties that are essential for protecting humans from chronic diseases. Moreover, the growing demand of consumers for nutritious and healthy foods is greatly promoting the increased intake of FVs. Allium (Alliaceae) is a perennial bulb plant genus of the Liliaceae family. They are customarily utilized as vegetable, medicinal, and ornamental plants and have an important role in agriculture, aquaculture, and the pharmaceutical industry. Allium plants produce abundant secondary metabolites, such as organosulfur compounds, flavonoids, phenols, saponins, alkaloids, and polysaccharides. Accordingly, Allium plants possess a variety of nutritional, biological, and health-promoting properties, including antimicrobial, antioxidant, antitumor, immunoregulatory, antidiabetic, and anti-inflammatory effects. This review aims to highlight the advances in the research on the bioactive components, physiological activities and clinical trials, toxicological assessment for safety, and applications of different Allium plants. It also aims to cover the direction of future research on the Allium genus. This review is expected to provide theoretical reference for the comprehensive development and utilization of Allium plants in the fields of functional foods, medicine, and cosmetics.

Allium vegetables: Traditional uses, phytoconstituents, and beneficial effects in inflammation and cancer

The genus Allium comprises of at least 918 species; the majority grown for dietary and medicinal purposes. This review describes the traditional uses, phytoconstituents, anti-inflammatory and anticancer activity, and safety profile of six main species, namely Allium sativum L. (garlic), Allium cepa L. (onions), Allium ampeloprasum L. (leek), Allium fistulosum L. (scallion), Allium schoenoprasum L. (chives) and Allium tuberosum Rottler (garlic chives). These species contain at least 260 phytoconstituents; mainly volatile compounds-including 63 organosulfur molecules-, saponins, flavonoids, anthocyanins, phenolic compounds, amino acids, organic acids, fatty acids, steroids, vitamins and nucleosides. They have prominent in vitro anti-inflammatory activity, and in vivo replications of such results have been achieved for all except for A. schoenoprasum. They also exert cytotoxicity against different cancer cell lines. Several anticancer phytoconstituents have been characterized from all except for A. fistulosum. Organosulfur constituents, saponins and flavonoid glycosides have demonstrated anti-inflammatory and anticancer activity. Extensive work has been conducted mainly on the anti-inflammatory and anticancer activity of A. sativum and A. cepa. The presence of anti-inflammatory and anticancer constituents in these two species suggests that similar bioactive constituents could be found in other species. This provides future avenues for identifying new Allium-derived anti-inflammatory and anticancer agents.

A review of anti-inflammatory, antioxidant, and immunomodulatory effects of Allium cepa and its main constituents

CONTEXT

Allium cepa L. (Liliaceae), known as onion, is consumed throughout the world. Onion and its derivatives including saponins, aglycones, quercetin, cepaenes, flavonoids, organosulfurs, and phenolic compounds, showed various pharmacological properties and therapeutic effects.

OBJECTIVE

Anti-inflammatory, antioxidant, and immunomodulatory effects of A. cepa and its main constituents, along with the underlying molecular mechanisms are presented.

METHODS

Databases including, Web of Knowledge, Medline/PubMed, Scopus, and Google Scholar were checked for articles published between 1996 and the end of July 2020, using the key-words Allium cepa, quercetin, anti-inflammatory, antioxidant and immunomodulatory.

RESULTS

A. cepa and its constituents mainly quercetin showed anti-inflammatory effects mediated via reduction of total and differential WBC counts, inhibition of chemotaxis of polymorphonuclear leukocytes, COX, and LOX pathways and prevented formation of leukotrienes and thromboxanes, prostaglandin E2 (PGE2) as onVCAM-1, NF-κB, MARK,d STAT-1, JNK, p38 and osteoclastogenesis. A. cepa and its derivatives showed antioxidant effect by decreasing lipid peroxidation, NAD(P)H, MDA, NO, LPO and eNOS but enhancing antioxidants such as SOD, CAT, GSH, GPx, GSPO, TrxR, SDH, GST and GR activities and thiol level. Immunomodulatory effects of the plant and quercetin was also shown by reduction of Th2 cytokines, IL-4, IL-5, and IL-13 as well as IL-6, IL-8, IL-10, IL-1β and TNF-α and IgE levels, but increased CD4 cells, IFN-γ level and IFN-γ/IL4 ratio (Th1/Th2 balance).

CONCLUSIONS

The effect of onion and its constituents on oxidative stress, inflammatory and immune system were shown indicating their therapeutic value in treatment of various diseases associated with oxidative stress, inflammation, and immune-dysregulation.

Molecular Action of Polyphenols in Leukaemia and Their Therapeutic Potential

Leukaemia is a malignant disease of the blood. Current treatments for leukaemia are associated with serious side-effects. Plant-derived polyphenols have been identified as potent anti-cancer agents and have been shown to work synergistically with standard chemotherapy agents in leukaemia cell lines. Polyphenols have multiple mechanisms of action and have been reported to decrease cell proliferation, arrest cell cycle and induce apoptosis via the activation of caspase (3, 8 and 9); the loss of mitochondrial membrane potential and the release of cytochrome c. Polyphenols have been shown to suppress activation of transcription factors, including NF-kB and STAT3. Furthermore, polyphenols have pro-oxidant properties, with increasing evidence that polyphenols inhibit the antioxidant activity of glutathione, causing oxidative DNA damage. Polyphenols also induce autophagy-driven cancer cell death and regulate multidrug resistance proteins, and thus may be able to reverse resistance to chemotherapy agents. This review examines the molecular mechanism of action of polyphenols and discusses their potential therapeutic targets. Here, we discuss the pharmacological properties of polyphenols, including their anti-inflammatory, antioxidant, anti-proliferative, and anti-tumour activities, and suggest that polyphenols are potent natural agents that can be useful therapeutically; and discuss why data on bioavailability, toxicity and metabolism are essential to evaluate their clinical use.

Pharmacological Properties of Allium cepa, Preclinical and Clinical Evidences; A Review

Onion or Allium cepa (A. cepa) is one of the most important condiment plants grown and consumed all over the world. This plant has various therapeutic effects attributed to its constituents, such as quercetin, thiosulphinates and phenolic acids. In the present article, various pharmacological and therapeutic effects of A. cepa were reviewed. Different online databases using keywords such as onion, A. cepa, therapeutic effects, and pharmacological effects until the end of December 2019 were searched for this purpose. Onion has been suggested to be effective in treating a broad range of disorders, including asthma, inflammatory disorders, dysentery, wounds, scars, keloids and pain. In addition, different studies have demonstrated that onion possesses numerous pharmacological properties, including anti-cancer, anti-diabetic and anti-platelet properties as well as the effect on bone, cardiovascular, gastrointestinal, nervous, respiratory, and urogenital systems effects such as anti-osteoporosis, anti-hypertensive, antispasmodic, anti-diarrheal, neuro-protective, anti-asthmatic and diuretic effects. The present review provides detailed the various pharmacological properties of onion and its constituents and possible underlying mechanisms. The results of multiple studies suggested the therapeutic effect of onion on a wide range of disorders.

Allium Flavonols: Health Benefits, Molecular Targets, and Bioavailability

Allium species are revered worldwide as vegetables, condiments, and spices as well as the therapeutic agents in traditional medicine. The bioactive compounds in alliums mainly include organosulfur compounds, polyphenols, dietary fibers, and saponins. Flavonoids, particularly flavonols from alliums, have been demonstrated to have the antioxidant, anticancer, hypolipidemic, anti-diabetic, cardioprotective, neuroprotective, and antimicrobial activities. However, flavonols are mostly characterized from onions and have not been comprehensively reviewed across different species. This article therefore focuses on flavonol profiles from different Allium species, their health effects, underlying molecular mechanisms, and bioavailability. Intriguingly, the functional health effects of flavonols were mainly ascribed to their antioxidant and anti-inflammatory activities involving a cascade of multiple signaling pathways. Although the Allium-derived flavonols offer tremendous potential in preventing chronic disease risks, in-depth studies are needed to translate their clinical application.

Leukemia therapy by flavonoids: Future and involved mechanisms

Flavonoids are a varied family of phytonutrients (plant chemicals) usually are detected in fruits and vegetables. In this big family, there exist more than 10,000 members that is separated into six chief subtypes: isoflavonols, flavonoenes, flavones, flavonols, anthocyanins, and chalcones. The natural compounds, such as fruits, have visible positive effects in regulating of survival involved signaling pathways that performance as the regulator of cell survival, growth, and proliferation. Researchers have established that commonly consumption up flavonoids decreases incidence and development risk of certain cancers, especially leukemia. Flavonoids have been able to induce apoptosis and stimulate cell cycle arrest in cancer cells via different pathways. Similarly, they have antiangiogenesis and antimetastasis capability, which were shown in wide ranges of cancer cells, particularly, leukemia. It seems that flavonoid because of their widespread approval, evident safety and low rate of side effects, have hopeful anticarcinogenic potential for leukemia therapy. Based on the last decade reports, the most important acting mechanisms of these natural compounds in leukemia cells are stimulating of apoptosis pathways by upregulation of caspase 3, 8, 9 and poly ADP-ribose polymerase (PARP) and proapoptotic proteins, particularly Bax activation. As well, they can induce cell cycle arrest in target cells not only via increasing of activated levels of p21 and p53 but also by inhibition of cyclins and cyclin-dependent kinases. Furthermore, attenuation of neclear factor-κB and signal transducer and activator of transcription 3 activation, suppression of signaling pathway and downregulation of intracellular antiapoptotic proteins are other significant antileukemic function mechanism of flavonoids. Overall, it appears that flavonoids are promising and effective compounds in the field of leukemia therapy. In this review, we tried to accumulate and revise most promising flavonoids and finally declared their major working mechanisms in leukemia cells.

Natural Compound Licochalcone B Induced Extrinsic and Intrinsic Apoptosis in Human Skin Melanoma (A375) and Squamous Cell Carcinoma (A431) Cells

Licochalcone B (Lico B), which is normally isolated from the roots of Glycyrrhiza inflata (Chinese Licorice), generally classified into organic compounds including retrochalcones. Potential pharmacological properties of Lico B include anti-inflammatory, anti-bacterial, anti-oxidant, and anti-cancer activities. However, its biological effects on melanoma and squamous cell carcinoma (SCC) are unknown. Based on these known facts, this study investigated the role of Lico B in apoptosis, through the extrinsic and intrinsic pathways and additional regulation of specificity protein 1 in human skin cancer cell lines. Annexin V/7-aminoactinomycin D staining, western blot analysis, mitochondrial membrane potential assay, and an anchorage-independent cell transformation assay demonstrated that Lico B treatment of human melanoma and SCC cells significantly inhibited cell proliferation and induced apoptotic cell death. More specifically, Lico B induced apoptosis through the regulation of specificity protein 1 and apoptosis-related proteins including CCAAT/enhancer-binding protein homologous protein, death receptors, and poly (ADP-ribose) polymerase. These results indicate that Lico B has apoptotic effect on A375 and A431 skin cancer cells, suggesting the potential value of Lico B for the treatment of human melanoma and SCC. Copyright © 2017 John Wiley & Sons, Ltd.

Lonicera japonica Thunb. Induces caspase-dependent apoptosis through death receptors and suppression of AKT in U937 human leukemic cells

Decoctions obtained from the dried flowers of Lonicera japonica Thunb. (Indongcho) have been utilized in folk remedies against inflammatory diseases. Recently, many agents that have used for inflammatory diseases are showing anticancer effects. Here, we have isolated polyphenols extracted from lyophilized Lonicera japonica Thunb (PELJ) and investigated the anticancer effects of PELJ on U937 cells. Here, we demonstrated that PELJ induced apoptosis by upregulation of DR4 and Fas, and further it is augmented by suppression of XIAP. In addition, The PELJ-induced apoptosis is at least in part by blocking PI3K/Akt pathway. These findings suggest that PELJ may provide evidence of anticancer activities on U937 cells. Further study for detailed mechanism and the effects on animal models is warranted to determine whether PELJ provide more conclusive evidence that PELJ which may provide a beneficial effect for treating cancer.

Anthocyanins from the Fruit of Vitis Coignetiae Pulliat Inhibit TNF-Augmented Cancer Proliferation, Migration, and Invasion in A549 Cells

Objective:

Anthocyanins belong to a class of flavonoids, exhibiting antioxidant and anti-inflammatory actions have been reported to have anti-cancer effects. Here, we investigated whether anthocyanins can inhibit cancer cell proliferation, invasion, and angiogenesis in human lung cancer A549 cells, which are critically involved in cancer metastasis.

Methods:

We used anthocyanins from fruits of Vitis coignetiae Pulliat (AIMs) which has been used in Korean folk medicine for the treatment of inflammatory diseases and cancers. We have performed cell proliferation assays, cell invasion assay, gelatin zymography, wound healing assay and western blotting to examine whether anthocyanins can inhibit cancer cell proliferation, invasion, and angiogenesis in A549 cells.

Result:

AIMs did not inhibit cancer cell proliferation on A549 cells. Also, AIMs suppressed cancer migration, and invasion by supressing MMP-2 and MMP-9 expression. The Immuno-blotting results also revealed that AIMs suppressed the proteins involved in cancer proliferation (COX-2, C-myc, cyclin D1), migration and invasion (MMP-2, MMP-9), anti-apoptosis (XIAP, and c-IAP2), adhesion and angiogenesis (ICAM-1, VEGF).

Conclusion:

This study demonstrates that the anthocyanins isolated from fruits of Vitis coignetiae Pulliat inhibit cancer proliferation, cancer migration, and invasion that is involve in cancer-metastasis. This study provides evidence that AIMs might have anti-cancer effects on human lung cancer.

Induction of apoptosis by Dae-Hwang-Mok-Dan-Tang in HCT-116 colon cancer cells through activation of caspases and inactivation of the phosphatidylinositol 3-kinase/Akt signaling

BACKGROUND

Dae-Hwang-Mok-Dan-Tang (DHMDT), a traditional Korean medicine, contains five species of medicinal plants and has been used to treat patients with digestive tract cancer for hundreds of years; however, its anticancer mechanism is poorly understood. In the present study, we investigated the proapoptotic effects of DHMDT in human colon cancer HCT-116 cells.

METHODS

Cytotoxicity was evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Apoptosis was detected using 4,6-diamidino-2-phenyllindile staining, agarose gel electrophoresis, and flow cytometry. The protein levels were determined using Western blot analysis. Caspase activity was measured using a colorimetric assay.

RESULTS

Treatment with DHMDT resulted in a growth inhibition coupled with apoptosis induction, which was associated with the downregulation of members of IAP (inhibitor of apoptosis protein) family, including XIAP and survivin, and the activation of caspase-9 and -3 accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase and phospholipase C-γ1. DHMDT treatment also showed a correlation with the translocation of proapoptotic Bax to mitochondria, the loss of mitochondrial membrane permeabilization, and the cytochrome c release from the mitochondria to the cytosol. Moreover, DHMDT increased the levels of death receptor-associated ligands and enhanced activation of caspase-8 and cleavage of its substrate, Bid. However, the pan-caspase inhibitor could reverse DHMDT-induced apoptosis. In addition, DHMDT suppressed the phosphoinositide 3-kinase (PI3K)/Akt pathway, and treatment with a potent inhibitor of PI3K further increased the apoptotic activity of DHMDT.

CONCLUSION

Our data showed that DHMDT induces HCT-116 cell apoptosis by activating intrinsic and extrinsic apoptosis pathways and by suppressing the PI3K/Akt signal pathway; however, further studies are needed to identify the active compounds.

Ursodeoxycholic Acid Induces Death Receptor-mediated Apoptosis in Prostate Cancer Cells

Background

Bile acids have anti-cancer properties in a certain types of cancers. We determined anticancer activity and its underlying molecular mechanism of ursodeoxycholic acid (UDCA) in human DU145 prostate cancer cells.

Methods

Cell viability was measured with an MTT assay. UDCA-induced apoptosis was determined with flow cytometric analysis. The expression levels of apoptosis-related signaling proteins were examined with Western blotting.

Results

UDCA treatment significantly inhibited cell growth of DU145 in a dose-dependent manner. It induced cellular shrinkage and cytoplasmic blebs and accumulated the cells with sub-G1 DNA contents. Moreover, UDCA activated caspase 8, suggesting that UDCA-induced apoptosis is associated with extrinsic pathway. Consistent to this finding, UDCA increased the expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, death receptor 4 (DR4) and death receptor 5 (DR5), and TRAIL augmented the UDCA-induced cell death in DU145 cells. In addition, UDCA also increased the expressions of Bax and cytochrome c and decreased the expression of Bcl-xL in DU145 cells. This finding suggests that UDCA-induced apoptosis may be involved in intrinsic pathway.

Conclusions

UDCA induces apoptosis via extrinsic pathway as well as intrinsic pathway in DU145 prostate cancer cells. UDCA may be a promising anti-cancer agent against prostate cancer.

Prodelphinidins isolated from Chinese bayberry leaves induces apoptosis via the p53-dependent signaling pathways in OVCAR-3 human ovarian cancer cells

Chinese bayberry leaves are rich in prodelphinidins. Since the isolation and purification of prodelphinidins is difficult, the association between the degree of prodelphinidin polymerization and their anti-carcinogenic activity remains ambiguous. The cytotoxic and apoptotic activities of prodelphinidin Chinese bayberry leaf extracts (PCBLs), oligomeric proanthocyanidins (OPAs) and polymeric proanthocyanidins (PPAs), isolated by normal-phase preparative high-performance liquid chromatography were investigated in OVCAR-3 human ovarian cancer cells. The PCBLs, OPAs and PPAs inhibited cancer cell growth and induced apoptosis via the caspase-dependent pathway. Apoptosis was triggered through the intrinsic pathway by upregulating the expression of several B-cell lymphoma-2 (Bcl-2) family proapoptotic proteins, including p53-upregulated modulator of apoptosis (PUMA), Bcl-2-associated X protein and Bcl-2-associated agonist of cell death, and by downregulating the antiapoptotic protein Bcl-extra large. Apoptosis was also triggered through the extrinsic pathway via the upregulation of death receptor 5 (DR5) and Fas expression. In addition, OPAs and PPAs induced caspase-dependent apoptosis at least partially through the inhibition of the protein kinase B signaling pathway. The knockdown of p53 by specific small interfering RNA resulted in the depletion of p53, and inhibited the OPA and PPA treatment-induced increases in p53, which led to a decrease in the expression of p21, DR5, Fas, PUMA and phosphatase and tensin homolog proteins. These observations demonstrate that p53 is a mediator of OPA and PPA-induced apoptosis in OVCAR-3 cells. The PPAs exhibited stronger anti-proliferative and pro-apoptotic activities compared with OPAs and PCBLs. These results suggest that PCBLs, OPAs and PPAs may be useful for the treatment of ovarian cancer.

Polyphenols from Korean prostrate spurge Euphorbia supina induce apoptosis through the Fas-associated extrinsic pathway and activation of ERK in human leukemic U937 cells

The Korean prostrate spurge Euphorbia supina (Euphorbiaceae family) has been used as a folk medicine in Korea against a variety of ailments such as bronchitis, hemorrhage, jaundice and multiple gastrointestinal diseases. Polyphenols from Korean E. supina (PES) which include quercetin and kaempferol derivatives have anticancer properties. Hence, we investigated the anticancer effects of PES on U937 human leukemic cells. Firstly, PES significantly inhibited the proliferation of U937 cells in a dose-dependent manner. PES induced accumulation of the sub-G1 DNA content (apoptotic cell population), apoptotic bodies and chromatin condensation and DNA fragmentation in the U937 cells. PES also induced activation of caspase-3, -8 and -9, subsequent cleavage of PARP, and significantly suppressed XIAP, cIAP-1 and cIAP-2 in a dose-dependent manner. Furthermore, PES activated Bid, and induced the loss of mitochondrial membrane potential (MMP, ΔΨm) along with upregulation of pro-apoptotic proteins (Bax and Bad), and downregulation of anti-apoptotic proteins (Bcl-2 and Bcl-xL) and cytochrome c release. The Fas receptor was upregulated by PES in a dose-dependent manner, suggesting that the extrinsic pathway was also involved in the PES-induced apoptosis. Moreover, the PES-induced apoptosis was at least in part associated with extracellular signal-regulated kinase (ERK) activation in the U937 human leukemic cells. This study provides evidence that PES may be useful in the treatment of leukemia.

Licochalcone B induces apoptosis of human oral squamous cell carcinoma through the extrinsic- and intrinsic-signaling pathways

Licochalcone B (Lico B), which belongs to the retrochalcone family, is isolated from the roots of Chinese licorice. Lico B has been reported to have several other useful pharmacological properties, such as anti-inflammatory, antibacterial, antioxidant, antiulcer, anticancer, and anti-metastasis activities. We elucidated the underlying mechanism by which Lico B can induce apoptosis in oral squamous cell carcinoma (OSCC). Our results showed that exposure of OSCC cells (HN22 and HSC4) to Lico B significantly inhibited cell proliferation in a time- and concentration-dependent manner. Lico B caused cell cycle arrest at G1 phase along with downregulation of cyclin D1 and upregulation of p21 and p27 proteins. Lico B also facilitated the diffusion of phospholipid phosphatidylserine (PS) from inner to outer leaflets of the plasma membrane with chromatin condensation, DNA fragmentation, accumulated sub-G1 population in a concentration-dependent manner. Moreover, Lico B promoted the generation of reactive oxygen species (ROS), which, in turn, can induce CHOP, death receptor (DR) 4 and DR5. Lico B treatment induced downregulation of anti-apoptotic proteins (Bid and Bcl-xl and Mcl-1), and up-regulation of pro-apoptotic protein (Bax). Lico B also led to the loss of mitochondrial membrane potential (MMP), resulting in cytochrome c release. As can be expected from the above results, the apoptotic protease activating factor-1 (Apaf-1) and survivin were oppositely expressed in favor of apoptotic cell death. This notion was supported by the fact that Lico B activated multi-caspases with cleavage of poly (ADP-ribose) polymerase (PARP) protein. Therefore, it is suggested that Lico B is a promising drug for the treatment of human oral cancer via the induction of apoptotic cell death.

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Poncirin Induces Apoptosis in AGS Human Gastric Cancer Cells through Extrinsic Apoptotic Pathway by up-Regulation of Fas Ligand

Poncirin, a natural bitter flavanone glycoside abundantly present in many species of citrus fruits, has various biological benefits such as anti-oxidant, anti-microbial, anti-inflammatory and anti-cancer activities. The anti-cancer mechanism of Poncirin remains elusive to date. In this study, we investigated the anti-cancer effects of Poncirin in AGS human gastric cancer cells (gastric adenocarcinoma). The results revealed that Poncirin could inhibit the proliferation of AGS cells in a dose-dependent manner. It was observed Poncirin induced accumulation of sub-G1 DNA content, apoptotic cell population, apoptotic bodies, chromatin condensation, and DNA fragmentation in a dose-dependent manner in AGS cells. The expression of Fas Ligand (FasL) protein was up-regulated dose dependently in Poncirin-treated AGS cells Moreover, Poncirin in AGS cells induced activation of Caspase-8 and -3, and subsequent cleavage of poly(ADP-ribose) polymerase (PARP). Inhibitor studies’ results confirm that the induction of caspase-dependent apoptotic cell death in Poncirin-treated AGS cells was led by the Fas death receptor. Interestingly, Poncirin did not show any effect on mitochondrial membrane potential (ΔΨm), pro-apoptotic proteins (Bax and Bak) and anti-apoptotic protein (Bcl-xL) in AGS-treated cells followed by no activation in the mitochondrial apoptotic protein caspase-9. This result suggests that the mitochondrial-mediated pathway is not involved in Poncirin-induced cell death in gastric cancer. These findings suggest that Poncirin has a potential anti-cancer effect via extrinsic pathway-mediated apoptosis, possibly making it a strong therapeutic agent for human gastric cancer.

The flavonoid morin from Moraceae induces apoptosis by modulation of Bcl-2 family members and Fas receptor in HCT 116 cells

It is evident based on literature that flavonoids from fruit can safely modulate cancer cell biology and induce apoptosis. Therefore, we investigated the anticancer activity of morin, a flavonoid which is plentiful in twigs of mulberry focusing on apoptosis, and its mechanisms. Morin upregulated the Fas receptor, and activates caspase-8, -9 and -3 in HCT-116 cells. Morin also activates Bid, and induced the loss of mitochondrial membrane potential (MMP, ∆Ψm) with Bax protein activation and cytochrome c release. In addition, morin induced ROS generation which was not blocked by N-acetylcysteine. Morin also suppressed Bcl-2 and cIAP-1, anti-apoptotic proteins, which may contribute to augmentation of morin-triggered apoptosis. As an upstream signaling pathway, suppressed Akt activity by morin was associated to apoptosis. This study suggests that morin induces caspase-dependent apoptosis through extrinsic pathway by upregulating Fas receptor as well as through the intrinsic pathway by modulating Bcl-2 and IAP family members, and ROS generation, and that Akt is the critical upstream signaling that regulates the apoptotic effect of morin in human colon cancer HCT-116 cells.

So-Cheong-Ryong-Tang induces apoptosis through activation of the intrinsic and extrinsic apoptosis pathways, and inhibition of the PI3K/Akt signaling pathway in non-small-cell lung cancer A549 cells

Background

So-Cheong-Ryong-Tang (SCRT), a traditional Korean medicine containing eight species of medicinal plant, has been used to treat patients with bronchial asthma and allergic rhinitis for hundreds of years; however, its anti-cancer potential is poorly understood. The present study was designed to evaluate the apoptotic effect of SCRT against human non-small-cell lung cancer (NSCLC) A549 cells.

Methods

The effects of SCRT on cell growth and viability were evaluated by trypan blue dye exclusion and 3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazoliumbromide (MTT) assays, respectively. Apoptosis was detected using 4,6-diamidino-2-phenyllindile (DAPI) staining, agarose gel electrophoresis and flow cytometry. The protein levels were determined by Western blot analysis. Caspase activity was measured using a colorimetric assay.

Results

SCRT treatment resulted in significantly decreased A549 cell growth and viability by induction of apoptosis. SCRT induced the translocation of pro-apoptotic Bax to the mitochondria, mitochondrial membrane permeabilization, cytochrome c release from mitochondria to cytosol, and activated caspase-9 and caspase-3. SCRT also increased death receptor-associated ligands and enhanced the activation of caspase-8 and cleavage of its substrate Bid. However, the pan-caspases inhibitor significantly blocked the SCRT-induced apoptosis, suggesting that it is a caspase-dependent pathway. In addition, SCRT suppressed the phosphorylation of phosphoinositide 3-kinase (PI3K) and Akt, and treatment with a potent inhibitor of PI3K further increased the apoptotic activity of SCRT.

Conclusions

These findings suggest that SCRT may play its anti-cancer actions partly through a suppression of the PI3K/Akt signal pathway in A549 cells, and further in vivo studies on the potential of SCRT for prevention and therapy of NSCLCs are warranted.

Polyphenols Isolated from Allium cepa L. Induces Apoptosis by Induction of p53 and Suppression of Bcl-2 through Inhibiting PI3K/Akt Signaling Pathway in AGS Human Cancer Cells

Background:

The extract of Allium cepa Linn is commonly used as adjuvant food for cancer therapy. We assumed that it includes a potential source of anti-cancer properties.

Methods:

We investigated anti-cancer effects of polyphenols extracted from lyophilized A. cepa Linn (PEAL) in AGS human cancer cells.

Results:

PEAL inhibited cell growth in a dose-dependent manner. It was related to caspase-dependent apoptosis. We confirmed this finding with annexin V staining. PEAL up-regulated p53 expression, and subsequent Bax induction, down regulated Bcl-2 protein, anti-apoptotic protein. In addition, PEAL suppressed Akt activity and PEAL-induced apoptosis were significantly accentuated with Akt inhibitor (LY294002).

Conclusions:

Our data suggested that PEAL induce caspase-dependent apoptosis through mitochondrial pathway by up-regulating p53 protein, and subsequent Bax protein as well as by modulating Bcl-2 protein, and that PEAL induces caspase-dependent apoptosis at least in part through the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. This study provides evidence that PEAL might be useful for the treatment of cancer.