Characterization of aroma-active compounds in Chinese quince (Pseudocydonia sinensis Schneid) by aroma dilution analyses.

Aroma-active compounds in the peel and pulp of Chinese quince fruits were extracted by high-vacuum distillation (HVD) and headspace solid-phase microextraction (HS-SPME) methods and identified by gas chromatography-olfactometry (GC-O) combined with aroma dilution analyses. Ethyl 2-methylpropanoate, ethyl (E)-2-butenoate, ethyl 2-methylbutanoate, methional, (Z)-3-hexenyl acetate, ß-ionone, ethyl nonanoate, and γ-decalactone were detected as the potent aroma-active compounds (log3FD factors≥5) in the peel of Chinese quince, while hexanal, (Z)-3-hexenal, and (Z)-3-hexenol, which have a green odor note, were potent aroma-active compounds with high log3FD factors (≥3) in the pulp of Chinese quince. In particular, ethyl propanoate, ethyl (E)-2-butenoate, and (Z)-3-hexenyl acetate-which had sweet and fruity aroma notes with relatively high FD factors-were detected in the samples extracted by HS-SPME.

3,3'-Diindolylmethane suppresses high-fat diet-induced obesity through inhibiting adipogenesis of pre-adipocytes by targeting USP2 activity.

SCOPE: Indole-3-carbinol (I3C), a derivative abundant in cruciferous vegetables such as cabbage, is well known for its various health benefits such as chemo-preventive and anti-obesity effects. I3C is easily metabolized to 3,3'-diindolylmethane (DIM), a more stable form, in acidic conditions of the stomach. However, the anti-obesity effect of DIM has not been investigated clearly. We sought to investigate the effect of DIM on diet-induced obesity and to elucidate its underlying mechanisms. METHODS AND RESULTS: High-fat diet (HFD)-fed obese mouse and MDI-induced 3T3-L1 adipogenesis models were used to study the effect of DIM. We observed that the administration of DIM (50 mg/kg BW) significantly suppressed HFD-induced obesity, associated with a decrease in adipose tissue. Additionally, we observed that DIM treatment (40 and 60 µM), but not I3C treatment, significantly inhibited MDI-induced adipogenesis by reducing the levels of several adipogenic proteins such as PPAR-γ and C/EBPα. DIM, but not I3C, suppressed cell cycle progression in the G1 phase, which occurred in the early stage of adipogenesis, inducing post-translational degradation of cyclin D1 by inhibiting ubiquitin specific peptidase 2 (USP2) activities. CONCLUSION: Our findings indicate that cruciferous vegetables, which can produce DIM as a metabolite, have the potential to prevent or treat chronic obesity.

Rg3-enriched ginseng extract ameliorates scopolamine-induced learning deficits in mice.

BACKGROUND: Ginseng (Panax ginseng C.A. Meyer) has been used as a traditional herb in the treatment of many medical disorders. Ginsenosides, which are triterpene derivatives that contain sugar moieties, are the main pharmacological ingredients in ginseng. This study was designed to investigate the effect of ginsenoside Rg3-enriched ginseng extract (Rg3GE) on scopolamine-induced memory impairment in mice. METHODS: Rg3GE (50 and 100 mg/kg) were administered to C57BL/6 mice by oral gavage for 14 days (days 1-14). Memory impairment was induced by scopolamine (1 mg/kg, intraperitoneal injection) for 6 days (days 914). The Morris water maze test was used to assess hippocampus-dependent spatial memory. The effects of scopolamine with or without Rg3GE on acetylcholinesterase and nuclear factor-κB (NF-κB) in the hippocampus were also examined. RESULTS: Mice with scopolamine treatment alone showed impairments in the acquisition and retention of spatial memory. Mice that received Rg3GE and scopolamine showed no scopolamine-induced impairment in the acquisition of spatial memory. Oral administration of Rg3GE suppressed the scopolamine-mediated increase in acetylcholinesterase activity and stimulation of the NF-κB pathway (i.e., phosphorylation of p65) in the hippocampus. CONCLUSION: These findings suggest that Rg3GE may stabilize scopolamine-induced memory deficits through the inhibition of acetylcholinesterase activity and NF-κB signaling in the hippocampus.

Dehydroglyasperin C suppresses TPA-induced cell transformation through direct inhibition of MKK4 and PI3K.

Bioactive natural compounds from plant-derived sources have received substantial interest due to their potential therapeutic and preventive effects toward various human diseases. Licorice (Glycyrrhiza), a frequently-used component in traditional oriental medicines, has been incorporated into recipes not only to enhance taste, but also to treat various conditions including inflammation, chronic fatigue syndrome, and even cancer. Dehydroglyasperin C (DGC) is a major isoflavone found in the root of licorice. In the present study, we investigated the cancer chemopreventive effect of DGC and the underlying molecular mechanisms involved, by analyzing its effects on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic cell transformation and cyclooxygenase (COX)-2 expression in JB6 P+ mouse epidermal cells. DGC treatment attenuated TPA-induced activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) transcriptional activation, two major regulators of TPA-induced cell transformation, and COX-2 expression. TPA-induced phosphorylation of p38, JNK1/2 and Akt was also suppressed by DGC. Kinase assay data revealed that DGC inhibited the kinase activity of MKK4 and PI3K and this outcome was due to direct physical binding with DGC. Notably, DGC bound directly to MKK4 and PI3K in an ATP-competitive manner. Taken together, these results suggest that DGC exhibits cancer chemopreventive potential via its inhibitory effect on TPA-induced neoplastic cell transformation and COX-2 modulation through regulation of the MKK4 and PI3K pathways.

The retinoic acid derivative, ABPN, inhibits pancreatic cancer through induction of Nrdp1.

Combination chemotherapy for the treatment of pancreatic cancer commonly employs gemcitabine with an EGFR inhibitor such as erlotinib. Here, we show that the retinoic acid derivative, ABPN, exhibits more potent anticancer effects than erlotinib, while exhibiting less toxicity toward noncancerous human control cells. Low micromolar concentrations of ABPN induced apoptosis in BxPC3 and HPAC pancreatic cancer cell lines, concomitant with a reduction in phosphorylated EGFR as well as decreased ErbB3, Met and BRUCE protein levels. The degradation of ErbB3 is a result of proteasomal degradation, possibly due to the ABPN-dependent upregulation of Nrdp1. Administration of ABPN showed significant reductions in tumor size when tested using a mouse xenograft model, with higher potency than erlotinib at the same concentration. Analysis of the tumors demonstrated that ABPN treatment suppressed ErbB3 and Met and induced Nrdp1 in vivo. The data suggest that ABPN may be more suitable in combination chemotherapy with gemcitabine than the more widely used EGFR inhibitor, erlotinib.

Identification of a Dual Inhibitor of Janus Kinase 2 (JAK2) and p70 Ribosomal S6 Kinase1 (S6K1) Pathways.

Bioactive phytochemicals can suppress the growth of malignant cells, and investigation of the mechanisms responsible can assist in the identification of novel therapeutic strategies for cancer therapy. Ginger has been reported to exhibit potent anti-cancer effects, although previous reports have often focused on a narrow range of specific compounds. Through a direct comparison of various ginger compounds, we determined that gingerenone A selectively kills cancer cells while exhibiting minimal toxicity toward normal cells. Kinase array screening revealed JAK2 and S6K1 as the molecular targets primarily responsible for gingerenone A-induced cancer cell death. The effect of gingerenone A was strongly associated with relative phosphorylation levels of JAK2 and S6K1, and administration of gingerenone A significantly suppressed tumor growth in vivo. More importantly, the combined inhibition of JAK2 and S6K1 by commercial inhibitors selectively induced apoptosis in cancer cells, whereas treatment with either agent alone did not. These findings provide rationale for dual targeting of JAK2 and S6K1 in cancer for a combinatorial therapeutic approach.

Transient receptor potential vanilloid type-1 channel regulates diet-induced obesity, insulin resistance, and leptin resistance.

Insulin resistance is a major characteristic of obesity and type 2 diabetes, but the underlying mechanism is unclear. Recent studies have shown a metabolic role of capsaicin that may be mediated via the transient receptor potential vanilloid type-1 (TRPV1) channel. In this study, TRPV1 knockout (KO) and wild-type (WT) mice (as controls) were fed a high-fat diet (HFD), and metabolic studies were performed to measure insulin and leptin action. The TRPV1 KO mice became more obese than the WT mice after HFD, partly attributed to altered energy balance and leptin resistance in the KO mice. The hyperinsulinemic-euglycemic clamp experiment showed that the TRPV1 KO mice were more insulin resistant after HFD because of the ∼40% reduction in glucose metabolism in the white and brown adipose tissue, compared with that in the WT mice. Leptin treatment failed to suppress food intake, and leptin-mediated hypothalamic signal transducer and activator of transcription (STAT)-3 activity was blunted in the TRPV1 KO mice. We also found that the TRPV1 KO mice were more obese and insulin resistant than the WT mice at 9 mo of age. Taken together, these results indicate that lacking TRPV1 exacerbates the obesity and insulin resistance associated with an HFD and aging, and our findings further suggest that TRPV1 has a major role in regulating glucose metabolism and hypothalamic leptin's effects in obesity.

MLK3 is a novel target of dehydroglyasperin D for the reduction in UVB-induced COX-2 expression in vitro and in vivo.

Dehydroglyasperin D (DHGA-D), a compound present in licorice, has been found to exhibit anti-obesity, antioxidant and anti-aldose reductase effects. However, the direct molecular mechanism and molecular targets of DHGA-D during skin inflammation remain unknown. In the present study, we investigated the effect of DHGA-D on inflammation and its mechanism of action on UVB-induced skin inflammation in HaCaT human keratinocytes and SKH-1 hairless mice. DHGA-D treatment strongly suppressed UVB-induced COX-2 expression, PGE2 generation and AP-1 transactivity in HaCaT cells without affecting cell viability. DHGA-D also inhibited phosphorylation of the mitogen-activated protein kinase kinase (MKK) 3/6/p38, MAPK/Elk-1, MKK4/c-Jun N-terminal kinase (JNK) 1/2/c-Jun/mitogen, and stress-activated protein kinase (MSK), whereas phosphorylation of the mixed-lineage kinase (MLK) 3 remained unaffected. Kinase and co-precipitation assays with DHGA-D Sepharose 4B beads showed that DHGA-D significantly suppressed MLK3 activity through direct binding to MLK3. Knockdown of MLK3 suppressed COX-2 expression as well as phosphorylation of MKK4/p38 and MKK3/6/JNK1/2 in HaCaT cells. Furthermore, Western blot assay and immunohistochemistry results showed that DHGA-D pre-treatment significantly inhibits UVB-induced COX-2 expression in vivo. Taken together, these results indicate that DHGA-D may be a promising anti-inflammatory agent that mediates suppression of both COX-2 expression and the MLK3 signalling pathway through direct binding and inhibition of MLK3.

Butein, a novel dual inhibitor of MET and EGFR, overcomes gefitinib-resistant lung cancer growth.

Lung cancer is a leading cause of death worldwide and MET amplification is a major therapeutic limitation in acquired-resistance lung cancer. We hypothesized that butein, a phytochemical, can overcome gefitinib-induced resistance by targeting both EGFR and MET in non-small cell lung cancer (NSCLC). To investigate the ability of butein to target EGFR and MET, we used in silico docking, a library of natural compounds and kinase assays. The effects of butein on growth, induction of apoptosis and expression of EGFR/MET signaling targets were examined in HCC827 (gefitinib-sensitive) and HCC827GR (gefitinib-resistant) NSCLC cells. Results were confirmed in vivo by a HCC827 or HCC827GR cell xenograft mouse model, each treated with vehicle, butein or gefitinib. Butein inhibited phosphorylation and kinase activity of EGFR and MET as well as soft agar colony formation and decreased viability of HCC827 and HCC827GR cells. Butein increased apoptosis-related protein expression in these cells. Results were confirmed by co-treatment with inhibitors of EGFR/MET or double knock-down. Finally, xenograft study results showed that butein strongly suppressed HCC827 and HCC827GR tumor growth. Immunohistochemical data suggest that butein inhibited Ki-67 expression. These results indicate that butein has potent anticancer activity and targets both EGFR and MET in acquired-resistance NSCLC.

Hirsutenone in Alnus extract inhibits akt activity and suppresses prostate cancer cell proliferation.

Although specific compounds found in some East Asian traditional medicines have been shown to exhibit bioactive properties, their molecular mechanisms of action remain elusive. The bark of the Alnus species has been used for the treatment of various pathological conditions including hemorrhage, alcoholism, fever, diarrhea, skin diseases, inflammation, and cancer in East Asia for centuries. In this study, we show that hirsutenone, a bioactive compound in Alnus japonica, exhibits anti-cancer effects against prostate cancer through a direct physical inhibition of Akt1/2. Hirsutenone suppressed anchorage-dependent and independent cell growth of PC3 and LNCaP human prostate cancer cells. Annexin V and Propidium iodide (PI) staining results demonstrated that hirsutenone strongly induces apoptotic cell death in both PC3 and LNCaP cells. Furthermore, treatment of hirsutenone attenuated phosphorylation of mammalian target of rapamycin (mTOR), a downstream substrate of Akt, without affecting Akt phosphorylation. Kinase and pull-down assay results clearly show that hirsutenone inhibits Akt1 and 2 by direct binding in an adenosine triphosphate (ATP)-noncompetitive manner in vitro and ex vivo. Our results show that hirsutenone suppresses human prostate cancer by targeting Akt1 and 2 as a key component to explain for anti-cancer activity of Alnus species.

20-O-ß-D-glucopyranosyl-20(S)-protopanaxadiol suppresses UV-Induced MMP-1 expression through AMPK-mediated mTOR inhibition as a downstream of the PKA-LKB1 pathway.

Various health effects have been attributed to the ginsenoside metabolite 20-O-ß-D-glucopyranosyl-20(S)-protopanaxadiol (GPD); however, its effect on ultraviolet (UV)-induced matrix metalloproteinase (MMP)-1 expression and the mechanism underlying this effect are unknown. We examined the inhibitory effect of GPD on UV-induced MMP-1 expression and its mechanisms in human dermal fibroblasts (HDFs). GPD attenuated UV-induced MMP-1 expression in HDFs and suppressed the UV-induced phosphorylation of mammalian target of rapamycin (mTOR) and p70(S6K) without inhibiting the activity of phosphatidylinositol 3-kinase and Akt, which are well-known upstream kinases of mTOR. GPD augmented the phosphorylation of liver kinase B1 (LKB1) and adenosine monophosphate-activated protein kinase (AMPK), which are inhibitors of mTOR, to a greater extent than UV treatment alone. Similar to GPD, 5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranosyl 5'-monophosphate (AICAR), an activator of AMPK, augmented UV-induced AMPK phosphorylation to a greater extent than UV treatment alone, resulting in the inhibition of MMP-1 expression. AICAR also decreased the phosphorylation of mTOR and p70(S6K). However, compound C, an antagonist of AMPK, increased MMP-1 expression. In HDF cells with AMPK knock-down using shRNA, MMP-1 expression was increased. These results indicate that AMPK activation plays a key role in MMP-1 suppression. Additionally, the cAMP-dependent protein kinase (PKA) inhibitor, H-89, antagonized GPD-mediated MMP-1 suppression via the inhibition of LKB1. Our results suggest that the suppressive activity of GPD on UV-induced MMP-1 expression is due to the activation of AMPK as a downstream of the PKA-LKB1 pathway.

Recovery effect of onion peel extract against H2 O2 -induced inhibition of gap-junctional intercellular communication is mediated through quercetin.

UNLABELLED: Cellular oxidative damage mediated by reactive oxygen species has been reported to inhibit gap-junctional intercellular communication (GJIC). In turn, the inhibition of GJIC can be attenuated by functional food compounds with antioxidant properties. In this study, we compared the protective effects of onion peel extract (OPE) and onion flesh extract (OFE) on oxidative stress-mediated GJIC inhibition, and investigated the mechanisms of action responsible. OPE restored H2 O2 -induced GJIC inhibition to a higher degree than OFE in WB-F344 rat liver epithelial cells. OPE was found to inhibit H2 O2 -induced phosphorylation of ERK1/2 and Cx43. A radical scavenging assay demonstrated superiority of OPE over OFE, suggesting that the observed effects might be mediated via an antioxidant mechanism. Quercetin is the major compound that is likely to be responsible for the protective effect against H2 O2 -mediated GJIC inhibition. This study suggests that OPE, a material often discarded, may be of value for the future development of functional food products. PRACTICAL APPLICATION: This study demonstrates that onion peel extract (OPE) exhibits a protective effect against the inhibition of gap-junctional intercellular communication (GJIC) mediated by H2 O2 , which is likely to occur via its antioxidant activity. OPE contains significant concentrations of bioactive phenolic compounds. Reductions in oxidative stress can lead to recovery of GJIC, which has been reported to be implicated in the prevention and treatment of cancers. These findings suggest that onion peel, a common waste product, could be used as potential resources for functional food development. Onion peel could be processed into a quercetin-rich powder or a pill for the prevention of cancer and other oxidative stress-related diseases.

Near-infrared reflectance spectroscopy as a rapid and non-destructive analysis tool for curcuminoids in turmeric.

INTRODUCTION: Turmeric has been widely used in curry powders as the main spice. Conventional chemical analysis such as high-performance liquid chromatography (HPLC) may take several hours to extract curcuminoids and prepare samples in many turmeric processing industries. OBJECTIVE: This study was conducted to evaluate curcuminoids in turmeric powder using near-infrared reflectance spectroscopy (NIRS). METHODS: All spectral acquisition ranged from 1100 to 2500 nm and a chemometrics analysis using partial least-squares (PLS) regression was performed to quantify the contents of individual curcuminoids. The HPLC was carried out (n = 129) to develop a PLS model based on the reference values. RESULTS: High correlation coefficient (R(2) > 0.93) and low standard error of cross-validation (SECV < 0.20 g/100 g) and standard error of prediction (SEP < 0.13 g/100 g) values were obtained for precision and accuracy. In addition, the ratio of prediction to deviation (RPD > 2.65) values was also calculated. CONCLUSION: Our results indicate that NIRS could be utilised as a control procedure or as an alternative rapid and effective quantification method.

Caffeic acid phenethyl ester, a major component of propolis, suppresses high fat diet-induced obesity through inhibiting adipogenesis at the mitotic clonal expansion stage.

In the present study, we aimed to investigate the antiobesity effect of CAPE in vivo, and the mechanism by which CAPE regulates body weight in vitro. To confirm the antiobesity effect of CAPE in vivo, mice were fed with a high fat diet (HFD) with different concentrations of CAPE for 5 weeks. CAPE significantly reduced body weight gain and epididymal fat mass in obese mice fed a HFD. In accordance with in vivo results, Oil red O staining results showed that CAPE significantly suppressed MDI-induced adipogenesis of 3T3-L1 preadipocytes. FACS analysis results showed that CAPE delayed MDI-stimulated cell cycle progression, thereby contributing to inhibit mitotic clonal expansion (MCE), which is a prerequisite step for adipogenesis. Also, CAPE regulated the expression of cyclin D1 and the phosphorylation of ERK and Akt, which are upstream of cyclin D1. These results suggest that CAPE exerts an antiobesity effect in vivo, presumably through inhibiting adipogenesis at an early stage of adipogenesis.

Pelargonidin attenuates PDGF-BB-induced aortic smooth muscle cell proliferation and migration by direct inhibition of focal adhesion kinase.

Pelargonidin is a natural red pigment found in fruits and vegetables, and has been reported to exhibit various effects potentially beneficial for human health. However, the possible preventive effects of pelargonidin toward atherosclerosis and mechanisms involved have not been investigated to date. Here, we compared the effects of pelargonidin and its glucoside-conjugated form, pelargonidin-3-glucoside (P3G), on proliferation and migration induced by platelet-derived growth factor (PDGF)-BB in human aortic smooth muscle cells (HASMCs). Pelargonidin, but not P3G, exhibited strong inhibitory effects against PDGF-BB-induced HASMC proliferation and migration, while suppressing PDGF-BB-induced ex vivo rat aortic ring sprouting. Immunoblot analysis revealed that pelargonidin inhibited PDGF-BB-induced phosphorylation of focal adhesion kinase (FAK) as well as F-actin reduction, whereas Src, mitogen-activated protein kinases (MAPKs) and Akt phosphorylation status were not altered. We also observed that the anti-proliferative and migratory effects of both pelargonidin and P3G corresponded with the extent of FAK inhibition. Both in vitro and ex vivo pull-down assays revealed that pelargonidin binds directly with FAK in an adenosine triphosphate-competitive manner, suggesting that FAK could be a molecular target of pelargonidin. Interestingly, pelargonidin did not exhibit inhibitory effects on the proliferation, migration or FAK phosphorylation of human umbilical vein endothelial cells (HUVECs). Taken together, our results suggest that pelargonidin exhibits potential preventive effects toward atherosclerosis through the attenuation of HASMC proliferation and migration, as well as aortic sprouting via the direct inhibition of FAK activity.

Cocoa phytochemicals: recent advances in molecular mechanisms on health.

Recent reports on cocoa are appealing in that a food commonly consumed for pure pleasure might also bring tangible benefits for human health. Cocoa consumption is correlated with reduced health risks of cardiovascular diseases, hypertension, atherosclerosis, and cancer, and the health-promoting effects of cocoa are mediated by cocoa-driven phytochemicals. Cocoa is rich in procyanidins, theobromine, (-)-epicatechin, catechins, and caffeine. Among the phytochemicals present in consumed cocoa, theobromine is most available in human plasma, followed by caffeine, (-)-epicatechin, catechin, and procyanidins. It has been reported that cocoa phytochemicals specifically modulate or interact with specific molecular targets linked to the pathogenesis of chronic human diseases, including cardiovascular diseases, cancer, neurodegenerative diseases, obesity, diabetes, and skin aging. This review summarizes comprehensive recent findings on the beneficial actions of cocoa-driven phytochemicals in molecular mechanisms of human health.

Increased expression of the receptor for advanced glycation end products in neurons and astrocytes in a triple transgenic mouse model of Alzheimer's disease.

The receptor for advanced glycation end products (RAGE) has been reported to have a pivotal role in the pathogenesis of Alzheimer's disease (AD). This study investigated RAGE levels in the hippocampus and cortex of a triple transgenic mouse model of AD (3xTg-AD) using western blotting and immunohistochemical double-labeling to assess cellular localization. Analysis of western blots showed that there were no differences in the hippocampal and cortical RAGE levels in 10-month-old adult 3xTg-AD mice, but significant increases in RAGE expression were found in the 22- to 24-month-old aged 3xTg-AD mice compared with those of age-matched controls. RAGE-positive immunoreactivity was observed primarily in neurons of aged 3xTg-AD mice with very little labeling in non-neuronal cells, with the notable exception of RAGE presence in astrocytes in the hippocampal area CA1. In addition, RAGE signals were co-localized with the intracellular amyloid precursor protein (APP)/amyloid beta (Aß) but not with the extracellular APP/Aß. In aged 3xTg-AD mice, expression of human tau was observed in the hippocampal area CA1 and co-localized with RAGE signals. The increased presence of RAGE in the 3xTg-AD animal model showing critical aspects of AD neuropathology indicates that RAGE may contribute to cellular dysfunction in the AD brain.

3,3'-Diindolylmethane inhibits lipopolysaccharide-induced microglial hyperactivation and attenuates brain inflammation.

Recent studies have revealed that microglial hyperactivation and neuroinflammation are implicated in development and progression of neurodegenerative diseases. In this study, we examined the beneficial effects of 3,3'-diindolylmethane (DIM) and indole-3-carbinol (I3C), dietary components found in cruciferous vegetables, on brain inflammation. DIM, a major metabolite of I3C, suppressed lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 in BV-2 microglia, but I3C did not. DIM, but not I3C, attenuated DNA-binding activity of nuclear factor-κB (NF-κB) and phosphorylation of inhibitor of κB, suggesting that DIM might inhibit microglial hyperactivation by attenuating inflammatory transcription factor NF-κB. In addition, DIM, but not I3C, protected primary cortical neurons from inflammatory toxicity induced by the conditioned media from LPS-stimulated BV-2 microglia, indicating that DIM might attenuate microglial hyperactivation-mediated neuronal death. In an in vivo model of neuroinflammation, DIM suppressed LPS-induced brain inflammation in mouse hippocampus, as determined by the number of Iba-1-positive cells and the mRNA expression of F4/80. Taken together, these results suggest that DIM may have beneficial potential against brain inflammation and neurodegenerative diseases through the negative regulation of the NF-κB signal pathway in microglia.

Quercetin suppresses invasion and migration of H-Ras-transformed MCF10A human epithelial cells by inhibiting phosphatidylinositol 3-kinase.

Quercetin is a major flavonoid compound found in red wine at a much higher concentration than the phytoalexin resveratrol. In this study, we examined potential anti-metastatic effects and found that compared to resveratrol, quercetin more potently inhibits H-Ras-induced invasion and migration in MCF10A human epithelial cells, an effect likely mediated by the mitigation of matrix metalloproteinase (MMP)-2 activation. We then measured Akt phosphorylation to investigate whether the decreased MMP-2 activation was attributable to the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt signalling. Quercetin, but not resveratrol at equivalent concentrations, suppressed the phosphorylation of Akt and was a more potent inhibitor of PI3K activity than resveratrol. An ex vivo binding assay further revealed that quercetin directly binds to PI3K. Collectively, these results suggest that PI3K is a molecular target of quercetin for the inhibition of H-Ras-induced invasion and migration of MCF10A cells.

The diarylheptanoid hirsutenone sensitizes chemoresistant ovarian cancer cells to cisplatin via modulation of apoptosis-inducing factor and X-linked inhibitor of apoptosis.

Cisplatin (CDDP) and its derivatives are considered first-line treatments for ovarian cancer (OVCA). However, despite initial results that often appear promising, in most cases patients will return with recurrent disease that fails to respond to further chemotherapy. We assayed a number of food phytochemicals with reported PI3K inhibitory ability to identify candidates that can influence CDDP treatment outcomes in chemoresistant OVCA cell lines. A direct comparison revealed that the diarylheptanoid hirsutenone from the tree bark of Alnus hirsuta var. sibirica was superior at inducing CDDP sensitivity in a number of chemoresistant cancer cell lines. Whereas hirsutenone treatment activated p53, its modest efficacy in p53-mutant and -null cell lines suggested the existence of a p53-independent mode of action. Further investigation revealed that hirsutenone causes CDDP-dependent apoptosis in chemoresistant cells by ubiquitin-proteasome-dependent X-linked inhibitor of apoptosis degradation and by enhancing the translocation of apoptosis-inducing factor from the mitochondria to the nucleus. This was found to be, at least in part, under the influence of upstream Akt activity, linking hirsutenone-dependent PI3K inhibition with downstream effects on apoptosis-inducing factor, X-linked inhibitor of apoptosis, and apoptosis. Our findings provide rationale for further investigation of the effects of hirsutenone on chemoresistant OVCA in clinical studies.