• Molecules and Cells
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• v.38 no.4
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• pp.327-335
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• 2015

Piperlongumine, a natural alkaloid isolated from the long pepper, selectively increases reactive oxygen species production and apoptotic cell death in cancer cells but not in normal cells. However, the molecular mechanism underlying piperlongumine-induced selective killing of cancer cells remains unclear. In the present study, we observed that human breast cancer MCF-7 cells are sensitive to piperlongumine-induced apoptosis relative to human MCF-10A breast epithelial cells. Interestingly, this opposing effect of piperlongumine appears to be mediated by heme oxygenase-1 (HO-1). Piperlongumine upregulated HO-1 expression through the activation of nuclear factor-erythroid-2-related factor-2 (Nrf2) signaling in both MCF-7 and MCF-10A cells. However, knockdown of HO-1 expression and pharmacological inhibition of its activity abolished the ability of piperlongumine to induce apoptosis in MCF-7 cells, whereas those promoted apoptosis in MCF-10A cells, indicating that HO-1 has anti-tumor functions in cancer cells but cytoprotective functions in normal cells. Moreover, it was found that piperlongumine-induced Nrf2 activation, HO-1 expression and cancer cell apoptosis are not dependent on the generation of reactive oxygen species. Instead, piperlongumine, which bears electrophilic ${\alpha},{\beta}$-unsaturated carbonyl groups, appears to inactivate Kelch-like ECH-associated protein-1 (Keap1) through thiol modification, thereby activating the Nrf2/HO-1 pathway and subsequently upregulating HO-1 expression, which accounts for piperlongumine-induced apoptosis in cancer cells. Taken together, these findings suggest that direct interaction of piperlongumine with Keap1 leads to the upregulation of Nrf2-mediated HO-1 expression, and HO-1 determines the differential response of breast normal cells and cancer cells to piperlongumine.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.679-682
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• 2002

The alkaloids, piperlongumine, piperine, pipernonaline, and piperoctadecalidine, isolated from Piper longum L., were found to inhibit the biosynthesis of aflatoxin $B_1$ (AF$B_1$) in Aspergillus flavus WRRC 3-90-42-12. Piperlongumine was the most active among the compounds tested, with a 96% inhibition of AF$B_1$biosynthesis at 0.2% (w/v) supplement in a potato dextrose agar (PDA) medium. The three other piperidine alkaloids, pipeline, pipernonaline, and piperoctadecalidine, also inhibited the biosynthesis of AF$B_1$. Of these three alkaloids, piperoctadecalidine exhibited a potent inhibitory activity with a 100% inhibition of AF$B_1$ production at 0.7% (w/v) supplement in a PDA medium. Therefore, piperlongumine and piperoctadecalidine could be used as antiaflatoxigenic agents in agricultural industries. To determine the antiaflatoxigenic mode of action of piperlongumine, further studies are needed.

• Molecules and Cells
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• v.42 no.12
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• pp.884-892
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• 2019

Piperlongumine (PL), a natural alkaloid compound isolated from long pepper (Piper longum), can selectively kill cancer cells, but not normal cells, by accumulation of reactive oxygen species (ROS). The objective of this study was to investigate functional roles of expression of SETDB1 and FosB during PL treatment in MCF7 breast cancer cells. PL downregulates SETDB1 expression, and decreased SETDB1 expression enhanced caspase 9 dependent-PARP cleavage during PL-induced cell death. PL treatment generated ROS. ROS inhibitor NAC (N-acetyl cysteine) recovered SETDB1 expression decreased by PL. Decreased SETDB1 expression induced transcriptional activity of FosB during PL treatment. PARP cleavage and positive annexin V level were increased during PL treatment with FosB overexpression whereas PARP cleavage and positive annexin V level were decreased during PL treatment with siFosB transfection, implying that FosB might be a pro-apoptotic protein for induction of cell death in PL-treated MCF7 breast cancer cells. PL induced cell death in A549 lung cancer cells, but molecular changes involved in the induction of these cell deaths might be different. These results suggest that SETDB1 mediated FosB expression may induce cell death in PL-treated MCF7 breast cancer cells.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.361-366
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• 2003

Anti-aflatoxigenic studies on synthetic pyridione alkaloids were conducted. Seven derivatives using piperlongumine as a leading compound were prepared from 3,4,5-trimethoxycinnamic acid (TMCA). These derivatives were analyzed for their structural confrmation and purity by HPLC, GC, GC/MS and $1^H-NMR$. 1-piperidin-1-yl-3-(3,4,5-trimethoxyphenyl)propenone (1) reaction with piperidine; 1-morpholin-4-yl-3-(3,4,5-trimethoypenyl)propenone (2) with morpholine; 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (3) with 3,5-dimethylpiperdine; 1-(2-methylpiperidine-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (4) with 2-methylpiperidine; 1-(3-hydroxypiperidin-1-yl)-3- (3,4,5-trimethoxyphenyl)propenone (5) with 3-hydroxypiperidine hydrochloride; 1-[3- (3,4,5-trimethoxyphenyl)acryloyl]piperidin-2-one (6) with ${\delta}-valerolactam;\; and\;ethyl\;1-[3-(3,4,5-trimethoxyphenyl)acyloyl]piperidine-4-carboxylate$ (7) with ethyl isonipectotate were synthesized respectively. All derivatives showed an inhibitory activity on aflatoxin $B_1$ production. In conclusion, we believe that they might be an agent for the control of mycotoxin in agricultural commodities.

• International Journal of Oral Biology
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• v.44 no.3
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• pp.89-95
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• 2019

Piperlongumine (PL) is a natural product found in long pepper (Piper longum). The pharmacological effects of PL are well known, and it has been used for pain, hepatoprotection, and asthma in Oriental medicine. No studies have examined the effects of PL on bone tissue or bone-related diseases, including osteoporosis. The current study investigated for the first time the inhibitory effects of PL on osteoclast differentiation, bone resorption, and osteoclastogenesis-related factors in RAW264.7 macrophages stimulated by the receptor activator for nuclear factor-${\kappa}B$ ligand (RANKL). Cytotoxicity was examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and osteoclast differentiation and bone resorption were confirmed by tartrate-resistant acid phosphatase (TRAP) staining and pit formation analysis. Osteoclast differentiation factors were confirmed by western blotting. PL exhibited toxicity in RAW264.7 macrophages, inhibiting osteoclast formation and bone resorption, in addition to inhibiting the expression of osteoclastogenesis-related factors, such as tumor necrosis factor receptor-associated factor 6 (TRAF6), c-Fos, and NFATc1, in RANKL-stimulated RAW264.7 macrophages. These findings suggest that PL is suitable for the treatment of osteoporosis, and it serves as a potential therapeutic agent for various bone diseases.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2003.11a
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• pp.53-57
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• 2003

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3211-3217
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• 2014

Background: The current study investigated the effects of Piper longumine on radio-sensitization of human breast cancer MDA-MB-231 cells and underlying mechanisms. Materials and Methods: Human breast cancer MDA-MB-231 cells were cultured in vitro and those in logarithmic growth phase were selected for experiments divided into four groups: control, X-ray exposed, Piper longumine, and Piper longumine combined with X-rays. Conogenic assays were performed to determine the radio-sensitizing effects. Cell survival curves were fitted by single-hit multi-target model and then the survival fraction (SF), average lethal dose ($D_0$), quasi-threshold dose ($D_q$) and sensitive enhancement ratio (SER) were calculated. Cell apoptosis was analyzed by flow cytometry (FCM). Western blot assays were employed for expression of apoptosis-related proteins (Bc1-2 and Bax) after treatment with Piper longumine and/or X-ray radiation. The intracellular reactive oxygen species (ROS) level was detected by FCM with a DCFH-DA probe. Results: The cloning formation capacity was decreased in the group of piperlongumine plus radiation, which displayed the values of SF2, D0, Dq significantly lower than those of radiation alone group and the sensitive enhancement ratio (SER) of D0 was1.22 and 1.29, respectively. The cell apoptosis rate was increased by the combination treatment of Piper longumine and radiation. Piper longumine increased the radiation-induced intracellular levels of ROS. Compared with the control group and individual group, the combination group demonstrated significantly decreased expression of Bcl-2 with increased Bax. Conclusions: Piper longumine at a non-cytotoxic concentration can enhance the radio-sensitivity of MDA-MB-231cells, which may be related to its regulation of apoptosis-related protein expression and the increase of intracellular ROS level, thus increasing radiation-induced apoptosis.

• Journal of Life Science
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• v.31 no.10
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• pp.929-936
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• 2021

In the present study, we screened candidate natural compounds which possess the strong anti-proliferative effects on human colorectal HCT116 cells using the commercial natural product library (Selleckchem, L1400) based on cell viability assay. Human colorectal cancer HCT116 cells were incubated with 50 μM of each compound from the natural product library, and then cell viability was measured by MTT assay. From the first screening, five different kinds of natural products (chrysin, diosmetin, emodin, piperlongumine, and tanshinone I) were selected based on cell viability assay in HCT116 cells and commercial availability. All selected natural products significantly decreased cell viabilities in HCT116 cells, whereas pro-apoptotic protein NAG-1 is strongly induced by chrysin or emodin treatment. Chrysin and emodin decreased cell viability in a dose-dependent manner. Moreover, chrysin and emodin increased the expression of pro-apoptotic NAG-1 protein in a dose- and time-dependent manner. In addition, PARP cleavage induced by chrysin or emodin was recovered in part by the transfection of NAG-1 siRNA indicating that NAG-1 may be one of the genes responsible for apoptosis induced by chrysin or emodin. Overall, our findings may provide basic screening data on natural products which possess anti-proliferative activities and may help to understand the molecular mechanisms of anti-proliferative and pro-apoptotic activities mediated by chrysin and emodin.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8041-8046
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• 2014

In-depth analysis of how TRAIL signals through death receptors to induce apoptosis in cancer cells using high throughput technologies has added new layers of knowledge. However, the wealth of information has also highlighted the fact that TRAIL induced apoptosis may be impaired as evidenced by experimental findings obtained from TRAIL resistant cancer cell lines. Overwhelmingly, increasing understanding of TRAIL mediated apoptosis has helped in identifying synthetic and natural compounds which can restore TRAIL induced apoptosis via functionalization of either extrinsic or intrinsic pathways. Increasingly it is being realized that biologically active phytochemicals modulate TRAIL induced apoptosis, as evidenced by cell-based studies. In this review we have attempted to provide an overview of how different phytonutrients have shown efficacy in restoring apoptosis in TRAIL resistant cancer cells. We partition this review into how the TRAIL mediated signaling landscape has broadened over the years and how TRAIL induced signaling machinery crosstalks with autophagic protein networks. Subsequently, we provide a generalized view of considerable biological activity of coumarins against a wide range of cancer cell lines and how coumarins (psoralidin and esculetin) isolated from natural sources have improved TRAIL induced apoptosis in resistant cancer cells. We summarize recent updates on piperlongumine, phenethyl isothiocyanate and luteolin induced activation of TRAIL mediated apoptosis. The data obtained from pre-clinical studies will be helpful in translation of information from benchtop to the bedside.