P2X7 receptor: a critical regulator and potential target for breast cancer.

Breast cancer is currently the most common cancer and the leading cause of cancer death among women worldwide. Advanced breast cancer is prone to metastasis, and there is currently no drug to cure metastatic breast cancer. The purinergic ligand-gated ion channel 7 receptor is an ATP-gated nonselective cation channel receptor and is involved in signal transduction, growth regulation, cytokine secretion, and tumor cell development. Recent studies have shown that upregulation of the P2X7 receptor in breast cancer can mediate AKT signaling pathways, Ca2 þ-activated SK3 potassium channels, and EMT and regulate the secretion of small extracellular vesicles to promote breast cancer invasion and migration, which are affected by factors such as hypoxia and ATP. In addition, studies have shown that microRNAs can bind to the 3' untranslated region of the P2X7 receptor, which affects the occurrence and development of breast cancer by upregulating and downregulating P2X7 receptor expression. Studies have shown that new P2X7 receptor inhibitors, such as emodin and Uncaria tomentosa, can inhibit P2X7 receptor-mediated breast cancer invasion and are expected to be used clinically. This article reviews the research progress on the relationship between the P2X7 receptor and breast cancer to provide new ideas and a basis for clinical diagnosis and treatment.

The phytoestrogens daidzein and equol inhibit the drug transporter BCRP/ABCG2 in breast cancer cells: potential chemosensitizing effect.

PURPOSE: The soy isoflavone genistein has been described to up-regulate breast cancer resistance protein (BCRP) and, thus, enhance chemoresistance in breast cancer cells. The aim of this work was to assess the effect of long- and short-term incubation with daidzein, the second most abundant soy isoflavone and its metabolite equol on the expression and activity of P-glycoprotein, multidrug resistance-associated proteins 1 and 2 (MRP1 and MRP2) and BCRP in breast cancer cells. METHODS: MCF-7 and MDA-MB-231 cells were treated with phytoestrogen concentrations within the range achieved in individuals with a high isoflavone intake. Transporter expression was evaluated at protein and mRNA level through western blot and qRT-PCR, respectively. Transporter activity was determined using doxorubicin, mitoxantrone and carboxy-dichlorofluorescein as substrates. RESULTS: Daidzein (5 µM) up-regulated MRP2- and down-regulated MRP1 protein expressions in MCF-7 and MDA-MB-231 cells, respectively. Both effects were ER-dependent, as determined using the antagonist ICI 182,780. The decrease in MRP1 mRNA in MDA-MB-231 cells indicates a transcriptional mechanism. On the contrary, MRP2 induction in MCF-7 cells takes place post-transcriptionally. Whereas changes in the transporter expression had a minor effect on the transporter activity, acute incubation with daidzein, R-equol and S-equol led to a strong inhibition of BCRP activity and an increase in the IC50 of BCRP substrates. CONCLUSIONS: In contrast to previous reports for genistein, daidzein and equol do not provoke a major up-regulation of the transporter expression but instead an inhibition of BCRP activity and sensitization to BCRP substrates.

Icariin inhibits autophagy and promotes apoptosis in SKVCR cells through mTOR signal pathway.

Autophagy is a conserved biological process, which is regulated by mTOR pathway and is reported to be a self-protective process of cancer cells to counteract apoptosis. Icariin is an active flavonoid that is reported to inhibit autophagy. In this study, we investigated whether Icariin could induce a reduction of cell proliferation by inhibiting autophagy. SKVCR cells, which are resistant to vincristine, were used for the investigation. We used CCK8 test and flow cytometry assay to study the effects of Icariin on cell proliferation, cell apoptosis and cell circle. We performed transmission electron microscope (TEM), immunohistochemical assay and western blotting assay to study the level of autophagy after Icariin treatment. Finally, we investigated whether the mTOR pathway is a target of Icariin by using mTOR inhibitor rapamycin and detected autophagy and apoptosis via flow cytometry assay, TEM, immunohistochemical assay and western blotting assay. Decreased proliferation and increased apoptosis was observed after Icariin treatment in SKVCR cells, together with decreased level of autophagy. Application of rapamycin could reverse the anti-autophagic and pro- apoptotic effect of Icariin. Icariin can inhibit autophagy and promote apoptosis in SKVCR cells by activating mTOR signal pathway. Icariin attenuates tumorigenesis by inhibiting autophagy and inducing apoptosis.

Central injection of fibroblast growth factor 1 induces sustained remission of diabetic hyperglycemia in rodents.

Type 2 diabetes (T2D) is among the most common and costly disorders worldwide. The goal of current medical management for T2D is to transiently ameliorate hyperglycemia through daily dosing of one or more antidiabetic drugs. Hypoglycemia and weight gain are common side effects of therapy, and sustained disease remission is not obtainable with nonsurgical approaches. On the basis of the potent glucose-lowering response elicited by activation of brain fibroblast growth factor (FGF) receptors, we explored the antidiabetic efficacy of centrally administered FGF1, which, unlike other FGF peptides, activates all FGF receptor subtypes. We report that a single intracerebroventricular injection of FGF1 at a dose one-tenth of that needed for antidiabetic efficacy following peripheral injection induces sustained diabetes remission in both mouse and rat models of T2D. This antidiabetic effect is not secondary to weight loss, does not increase the risk of hypoglycemia, and involves a novel and incompletely understood mechanism for increasing glucose clearance from the bloodstream. We conclude that the brain has an inherent potential to induce diabetes remission and that brain FGF receptors are potential pharmacological targets for achieving this goal.

The phytoestrogen genistein enhances multidrug resistance in breast cancer cell lines by translational regulation of ABC transporters.

Breast cancer is the most frequent malignancy in women. Multidrug resistance due to overexpression of ABC drug transporters is a common cause of chemotherapy failure and disease recurrence. Genistein (GNT) is a phytoestrogen present in soybeans and hormone supplements. We investigated the effect of GNT on the expression and function of ABC transporters in MCF-7 and MDA-MB-231 breast cancer cell lines. Results demonstrated an induction at the protein level of ABCC1 and ABCG2 and of ABCC1 in MCF-7 and MDA-MB-231, respectively. MCF-7 cells showed a concomitant increase in doxorubicin and mitoxantrone efflux and resistance, dependent on ABCG2 activity. ABCC1 induction by GNT in MDA-MB-231 cells modified neither drug efflux nor chemoresistance due to simultaneous acute inhibition of the transporter activity by GNT. All inductions took place at the translational level, as no increment in mRNA was observed and protein increase was prevented by cycloheximide. miR-181a, already demonstrated to inhibit ABCG2 translation, was down-regulated by GNT, explaining translational induction. Effects were independent of classical estrogen receptors. Results suggest potential nutrient-drug interactions that could threaten chemotherapy efficacy, especially in ABCG2-expressing tumors treated with substrates of this transporter.

Tumor-selective proteotoxicity of verteporfin inhibits colon cancer progression independently of YAP1.

Yes-associated protein 1 (YAP1) is a transcriptional coactivator in the Hippo signaling pathway. Increased YAP1 activity promotes the growth of tumors, including that of colorectal cancer (CRC). Verteporfin, a drug that enhances phototherapy to treat neovascular macular degeneration, is an inhibitor of YAP1. We found that verteporfin inhibited tumor growth independently of its effects on YAP1 or the related protein TAZ in genetically or chemically induced mouse models of CRC, in patient-derived xenografts, and in enteroid models of CRC. Instead, verteporfin exhibited in vivo selectivity for killing tumor cells in part by impairing the global clearance of high-molecular weight oligomerized proteins, particularly p62 (a sequestrome involved in autophagy) and STAT3 (signal transducer and activator of transcription 3; a transcription factor). Verteporfin inhibited cytokine-induced STAT3 activity and cell proliferation and reduced the viability of cultured CRC cells. Although verteporfin accumulated to a greater extent in normal cells than in tumor cells in vivo, experiments with cultured cells indicated that the normal cells efficiently cleared verteporfin-induced protein oligomers through autophagic and proteasomal pathways. Culturing CRC cells under hypoxic or nutrient-deprived conditions (modeling a typical CRC microenvironment) impaired the clearance of protein oligomers and resulted in cell death, whereas culturing cells under normoxic or glucose-replete conditions protected cell viability and proliferation in the presence of verteporfin. Furthermore, verteporfin suppressed the proliferation of other cancer cell lines even in the absence of YAP1, suggesting that verteporfin may be effective against multiple types of solid cancers.

Oligomer procyanidins (F2) isolated from grape seeds inhibits tumor angiogenesis and cell invasion by targeting HIF-1α in vitro.

Overexpression of hypoxia-inducible factor-1 (HIF-1) α, a transcription factor which immortalizes tumors by inducing expression of the genes involved in cell survival, migration and angiogenesis, is closely associated with poor prognosis, increased risk of metastasis and increased mortality. Oligomer procyanidins (F2), a natural fraction from grape seeds, has been demonstrated to have antioxidant and antitumor activities, however the antitumor effect of F2 targeting HIF-1α remains unknown. The present study showed that F2 markedly decreased HIF-1α and the expression of its target genes in cancer cells through inactivating the EGFR-PI3K-AKT-mTOR and MAPK-ERK1/2 pathways. Moreover, F2 suppressed vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 expressions, followed by the inhibition of tumor angiogenesis and cell invasion in a HIF-1α-dependent manner. Collectively, these findings indicate that the antitumor effect of F2 is, at least in part, mediated by suppressing HIF-1α-dependent pathway, and suggest that F2 may be a potentially useful agent for treatment of human cancer.

Targeting apoptosis pathways in cancer with alantolactone and isoalantolactone.

Alantolactone and isoalantolactone, main bioactive compounds that are present in many medicinal plants such as Inula helenium, L. Inula japonica, Aucklandia lappa, Inula racemosa, and Radix inulae, have been found to have various pharmacological actions including anti-inflammatory, antimicrobial, and anticancer properties, with no significant toxicity. Recently, the anticancer activity of alantolactone and isoalantolactone has been extensively investigated. Here, our aim is to review their natural sources and their anticancer activity with specific emphasis on mechanism of actions, by which these compounds act on apoptosis pathways. Based on the literature and also on our previous results, alantolactone and isoalantolactone induce apoptosis by targeting multiple cellular signaling pathways that are frequently deregulated in cancers and suggest that their simultaneous targeting by these compounds could result in efficacious and selective killing of cancer cells. This review suggests that alantolactone and isoalantolactone are potential promising anticancer candidates, but additional studies and clinical trials are required to determine their specific intracellular sites of actions and derivative targets in order to fully understand the mechanisms of therapeutic effects to further validate in cancer chemotherapy.

Differentially expressed proteins of MCF-7 human breast cancer cells affected by Zilongjin, a complementary Chinese herbal medicine.

PURPOSE: Zilongjin, a complementary Chinese herbal medicine, has been used to alleviate the adverse effects of chemotherapeutic drugs in cancer therapy. However, the mechanisms of anti-cancer activity of Zilongjin are still largely unkonwn. EXPERIMENTAL DESIGN: First, the proteomic approach of combined 2-DE and ESI-MS/MS was used to investigate the effect of Zilongjin on the protein expression in MCF-7 cells. Then, the differential expression of some proteins was confirmed by Western blot, cytoimmunofluoresecnce, and quantitative real-time RT-PCR analysis. RESULTS: The identified proteins with differential expression, involved in such events as protein translation, cellular signal transduction, cytoskeleton formation and transportation, include seven downregulating proteins, such as Eukaryotic translation initiation factor 3 subunit I, Eukaryotic translation initiation factor 1A Y-chromosomal, Ran-specific GTPase-activating protein, Ubiquitin-conjugating enzyme E2 N, Tropomodulin-3, Macrophage-capping protein, and Tumor protein D52, as well as two upregulating proteins, HSP ß-1 and keratin18. Moreover, the differential expression of three proteins was confirmed. CONCLUSIONS AND CLINICAL RELEVANCE: (i) These results provide a new insight into the molecular mechanisms of Zilongjin on therapy for breast cancer. (ii) The application of the proteomic approaches will result in the more extended appreciation of Chinese medicine than those known at present.

All trans retinoic acid nanodisks enhance retinoic acid receptor mediated apoptosis and cell cycle arrest in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is characterized by translocation t(11;14)(q13;q32), aggressive clinical behaviour, and poor patient outcomes following conventional chemotherapy. New treatment approaches are needed that target novel biological pathways. All trans retinoic acid (ATRA) is a key retinoid that acts through nuclear receptors that function as ligand-inducible transcription factors. The present study evaluated cell killing effects of ATRA-enriched nanoscale delivery particles, termed nanodisks (ND), on MCL cell lines. Results show that ATRA-ND induced cell death more effectively than naked ATRA (dimethyl sulphoxide) or empty ND. ATRA-ND induced reactive oxygen species (ROS) generation to a greater extent than naked ATRA. The antioxidant, N-acetylcysteine, inhibited ATRA-ND induced apoptosis. Compared to naked ATRA, ATRA-ND enhanced G1 growth arrest, up-regulated p21and p27, and down regulated cyclin D1. At ATRA concentrations that induced apoptosis, expression levels of retinoic acid receptor-alpha (RARalpha) and retinoid X receptor-gamma (RXRgamma) were increased. Compared to naked ATRA, ATRA-ND significantly stimulated transcriptional activity of RARA in a model carcinoma cell line. Furthermore, the RAR antagonist, Ro 41-5253, inhibited ATRA-ND induced ROS generation and prevented ATRA-ND induced cell growth arrest and apoptosis. In summary, incorporation of ATRA into ND enhanced the biological activity of this retinoid in cell culture models of MCL.

Pomegranate juice inhibits sulfoconjugation in Caco-2 human colon carcinoma cells.

Several fruit juices have been reported to cause food-drug interactions, mainly affecting cytochrome P450 activity; however, little is known about the effects of fruit juices on conjugation reactions. Among several fruit juices tested (apple, peach, orange, pineapple, grapefruit, and pomegranate), pomegranate juice potently inhibited the sulfoconjugation of 1-naphthol in Caco-2 cells. This inhibition was both dose- and culture time-dependent, with a 50% inhibitory concentration (IC(50)) value calculated at 2.7% (vol/vol). In contrast, no obvious inhibition of glucuronidation of 1-naphthol in Caco-2 cells was observed by any of the juices examined. Punicalagin, the most abundant antioxidant polyphenol in pomegranate juice, was also found to strongly inhibit sulfoconjugation in Caco-2 cells with an IC(50) of 45 microM, which is consistent with that of pomegranate juice. These data suggest that punicalagin is mainly responsible for the inhibition of sulfoconjugation by pomegranate juice. We additionally demonstrated that pomegranate juice and punicalagin both inhibit phenol sulfotransferase activity in Caco-2 cells in vitro, at concentrations that are almost equivalent to those used in the Caco-2 cells. Pomegranate juice, however, shows no effects on the expression of the sulfotransferase SULT1A family of genes (SULT1A1 and SULT1A3) in Caco-2 cells. These results indicate that the inhibition of sulfotransferase activity by punicalagin in Caco-2 cells is responsible for the reductions seen in 1-naphthyl sulfate accumulation. Our data also suggest that constituents of pomegranate juice, most probably punicalagin, impair the enteric functions of sulfoconjugation and that this might have effects upon the bioavailability of drugs and other compounds present in food and in the environment. These effects might be related to the anticarcinogenic properties of pomegranate juice.

Targeting survivin in cancer therapy.

BACKGROUND: Survivin is a structurally unique member of the inhibitor of apoptosis protein (IAP) family that acts as a suppressor of apoptosis and plays a central role in cell division. Owing to its massive upregulation in human tumors and its involvement in cancer progression and treatment resistance, survivin is currently undergoing extensive investigation as a novel therapeutic target. OBJECTIVE: The purpose of this review is to define the potential of survivin as a therapeutic target for new anticancer interventions. METHODS: The literature dealing with the therapeutic targeting of survivin has been carefully reviewed. RESULTS/CONCLUSION: Several preclinical studies have demonstrated that downregulation of survivin expression or function, accomplished by means of various strategies, reduced tumor growth potential, increased the apoptotic rate and sensitized tumor cells to chemotherapeutic drugs and radiation in different human tumor models. Moreover, the first survivin inhibitors are being currently evaluated in clinical settings.

Effects of curcumin on bladder cancer cells and development of urothelial tumors in a rat bladder carcinogenesis model.

Curcumin, a well-known dietary pigment derived from Curcuma longa, inhibited growth of several types of malignant cells both in vivo and in vitro. Its effects on cell proliferation and the induction of apoptosis in human bladder cancer cell lines and intravesical activity in a rat bladder tumor model were studied. Exposure of human bladder cancer cells to curcumin resulted in the induction of apoptotic cell death and caused cells to arrest in the G2/M phase. The anti-apoptotic Bcl-2 and Survivin protein was downregulated by the curcumin treatment together with enhancement of the Bax and p53 expression. The inhibitory activities of curcumin were stronger than those of cisplatin and could not be prevented by catalase pretreatment in T24 cells. Clonal assay indicated large-dose and short-term curcumin was lethal to bladder cancer cells. Moreover, the in vivo study revealed curcumin did induce apoptosis in situ, inhibit and slow the development of bladder cancer. These observations suggest that curcumin could prove an effective chemopreventive and chemotherapy agent for bladder cancer.

Honokiol, a constituent of oriental medicinal herb magnolia officinalis, inhibits growth of PC-3 xenografts in vivo in association with apoptosis induction.

PURPOSE: This study was undertaken to determine the efficacy of honokiol, a constituent of oriental medicinal herb Magnolia officinalis, against human prostate cancer cells in culture and in vivo. EXPERIMENTAL DESIGN: Honokiol-mediated apoptosis was assessed by analysis of cytoplasmic histone-associated DNA fragmentation. Knockdown of Bax and Bak proteins was achieved by transient transfection using siRNA. Honokiol was administered by oral gavage to male nude mice s.c. implanted with PC-3 cells. Tumor sections from control and honokiol-treated mice were examined for apoptotic bodies (terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay), proliferation index (proliferating cell nuclear antigen staining), and neovascularization (CD31 staining). Levels of Bcl-2 family proteins in cell lysates and tumor supernatants were determined by immunoblotting. RESULTS: Exposure of human prostate cancer cells (PC-3, LNCaP, and C4-2) to honokiol resulted in apoptotic DNA fragmentation in a concentration- and time-dependent manner irrespective of their androgen responsiveness or p53 status. Honokiol-induced apoptosis correlated with induction of Bax, Bak, and Bad and a decrease in Bcl-xL and Mcl-1 protein levels. Transient transfection of PC-3 cells with Bak- and Bax-targeted siRNAs and Bcl-xL plasmid conferred partial yet significant protection against honokiol-induced apoptosis. Oral gavage of 2 mg honokiol/mouse (thrice a week) significantly retarded growth of PC-3 xenografts without causing weight loss. Tumors from honokiol-treated mice exhibited markedly higher count of apoptotic bodies and reduced proliferation index and neovascularization compared with control tumors. CONCLUSION: Our data suggest that honokiol, which is used in traditional oriental medicine for the treatment of various ailments, may be an attractive agent for treatment and/or prevention of human prostate cancers.

Melatonin stimulates HSP27 phosphorylation in human pancreatic carcinoma cells (PANC-1).

UNLABELLED: Heat shock protein 27 (HSP27) is a cytoprotective chaperone, activated by stressful stimuli. HSP27 modulates aggregation and degradation of many proteins. Recent evidence suggests that HSP27 could be involved in the progression of tumor growth and in the development of resistance of various tumors to chemo- and radiotherapy. It has been reported that melatonin protects pancreatic cells and various tissues against inflammatory damage. Previous experimental studies have shown that melatonin stimulates pancreatic enzyme secretion and improves the outcome of experimental pancreatitis. To investigate whether melatonin could affect HSP27 protein level in human pancreatic carcinoma cells (PANC-1). PANC-1 cells were incubated in the standard medium DMEM supplemented with 10% fetal bovine serum at 37 degrees C with 5% CO2 and humidified atmosphere under basal conditions or in the presence of decreasing doses of melatonin (10(-6) - 10(-12)M). Control experiments were performed with the vehicle only (0,1% DMSO) without melatonin. After 24 h and 48 h the cells were harvested, the cytoplasmic and nuclear proteins were isolated for western blot and immunoblotting studies. Incubation of the PANC-1 cells with melatonin resulted in the stimulation both cytoplasmic and nuclear nonphosphorylated HSP27 protein levels after 24 h of incubation, however, above pools of nonphosphorylated chaperone protein levels were strongly diminished after subsequent 24 h. These changes were accompanied by marked rise of nuclear phosphorylated HSP27. The significant increase of this nuclear protein was observed after 48h of incubation. CONCLUSION: Melatonin stimulates phosphorylation of HSP27 in human pancreatic carcinoma cells (PANC-1).

Calcium and survivin are involved in the induction of apoptosis by dihydroartemisinin in human lung cancer SPC-A-1 cells.

Dihydroartemisinin (DHA), a semisynthetic derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua, is an effective novel antimalarial drug. Recent studies suggest that it also has anticancer effects. The present study investigated the apoptosis activity of DHA in cultured human lung cancer cells by terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay and flow cytometry. Intracellular free calcium concentrations in the lung cancer cells were evaluated by laser scanning confocal microscopy using Fura-3/AM as probe. The observations also indicated that DHA downregulated the mRNA and protein expression level of survivin in the lung cancer cell line SPC-A-1 cells, whereas it did not affect those of caspase-4. These results demonstrated that DHA can induce apoptosis of lung cancer cell line SPC-A-1 cells and that calcium and survivin participated in the apoptotic signalling pathways.

Mechanisms of selenium down-regulation of androgen receptor signaling in prostate cancer.

Prevention trials showed that selenium reduced prostate cancer incidence by 50%, establishing selenium as a promising chemopreventive agent for prostate cancer. Selenium inhibited human prostate cancer cell growth, blocked cell cycle progression at multiple transition points, and induced apoptotic cell death. Previous studies showed a novel mechanism of selenium anticancer action in which selenium markedly reduces androgen signaling and androgen receptor (AR)-mediated gene expression, including prostate-specific antigen (PSA), in human prostate cancer cells. The molecular mechanisms of selenium-mediated down-regulation of AR signaling are not clear. In this study, a systemic approach was taken to examine the modification of androgen signaling by selenium in human prostate cancer cells. In addition to reduced AR mRNA expression, selenium was found to initially increase the stability of AR mRNA within 6 hours while decreasing the stability of AR mRNA after 8 hours. Selenium increased AR protein degradation and reduced AR nuclear localization. Scatchard analysis indicated that selenium did not affect ligand binding to AR in LNCaP cells. Chromatin immunoprecipitation analyses showed that DHT increased the recruitment of AR and coactivators, such as SRC-1 and TIF-2, to the promoter of the PSA gene, and that recruitment was greatly diminished in the presence of 5 micromol/L selenium. On the other hand, selenium enhanced the recruitment of corepressors, such as SMRT, to the promoter of the PSA gene. Taken together, these results suggest that selenium disrupts AR signaling at multiple stages, including AR mRNA expression, mRNA stability, protein degradation, nuclear translocation, and recruitment of coregulators.

Ponicidin, an ent-kaurane diterpenoid derived from a constituent of the herbal supplement PC-SPES, Rabdosia rubescens, induces apoptosis by activation of caspase-3 and mitochondrial events in lung cancer cells in vitro.

Ponicidin, an ent-kaurane diterpenoid derived from a constituent of the herbal supplement PC-SPES, Rabdosia rubescens, is recently reported to have anti-tumor effects on a large variety of cancers. In this study, we demonstrate that ponicidin exhibits cytotoxicity, induces apoptosis, disrupts the mitochondrial membrane potential, and triggers the activation of caspase-3, -8 and -9 in lung cancer A549 and GLC-82 cells. Ponicidin treatment of lung cancer cells caused downregulation of anti-apoptotic protein Bcl-2 and survivin as well as upregulaton of pro-apoptotic protein Bax in a time dependent manner when apoptosis ocurred. Ponicidin induced activation of caspase-3 can be blocked by a caspase-3-specific inhibitor z-DEVD-FMK Furthermore, the caspase-8-specific inhibitor z-IETD-FMK could block the ponicidin-induced activation of caspase-3, PARP cleavage, and prevented the release of cytochrome c from mitochondria into the cytoplasm. This indicate that activated caspase-8 initiates the release of cytochrome c during ponicidin-induced apoptosis. We therefore conclude that ponicidin has significant apoptosis-inducing effects by activation of caspase-3 -8, and -9 as well as downregulation of anti-apoptotic protein Bcl-2, survivin and upregulation of pro-apoptotic protein Bax, with caspase-8 acting as an upstream activator. The data offer a potential mechanism for ponicidin-induced apoptosis in lung cancer cells, suggesting that ponicidin may severve as an effective reagent for the treatment of lung cancer, and that in vivo anti-cancer effects as well as its potential clinical effectiveness need further investigation.

Site specific therapy: an integrative approach to treating melanoma.

There have been many proposed theories for effectively treating melanoma, especially through the regulation of histamine. Histamine has been proven to be a major regulator of the immune system's T-helper cell subset balance and major shifts in this balance towards TH2 cytokines have contributed to diseases such as asthma, lupus and cancer. Histamine also causes suppression of interferon-induced proteins needed for anti-tumor response and activates T-suppressor cell function in cancers such as squamous cell carcinoma and melanoma. Scientific evidence has suggested the possibility of an anthistamine approach as treatment to these diseases and for melanoma, there has been great promise. This is due to the fact that melanotic cells have been elucidated to express histamine receptors and as a result, regulation of histamine could occur specifically at the site of these epidermal growths. Another factor to consider is how effective an inflammatory response can be when combined with regulation of histamine. Inflammation is a very powerful tool against pathogenic environments by causing cytokine recruitment and migration of dendritic cells to infected sites. Adequate stimulation of an inflammatory response at the specific site of any cancerous region would greatly weaken its evasive mechanisms. However, there are no reports showing high efficacy utilizing the benefits of regulating inflammation and histamine that could cause TH1 subset levels to predominate, down-regulate T-suppressor cells, up-regulate interferon-induced proteins and properly sustain migration of dendritic cells concurrently. These benefits have been proven in separate instances for a range of diseases but have not been assessed as a combined modality for melanoma therapy. Therefore successful melanoma treatment should integrate these principles involving: the use of H2 antagonists for preventing the negative effects of histamine, monoclonal antibodies to ensure an effective dendritic cell response, and routine pro-inflammatory induction at the specific site of the melanotic tissue to ensure recognition of the cancer that has evaded immunity.

Medicinal mushroom modulators of molecular targets as cancer therapeutics.

Empirical approaches to discover anticancer drugs and cancer treatments have made limited progress in the past several decades in finding a cure for cancer. The expanded knowledge of the molecular basis of tumorigenesis and metastasis, together with the inherently vast structural diversity of natural compounds found in mushrooms, provided unique opportunities for discovering new drugs that rationally target the abnormal molecular and biochemical signals leading to cancer. This review focuses on mushroom low-molecular-weight secondary metabolites targeting processes such as apoptosis, angiogenesis, metastasis, cell cycle regulation, and signal transduction cascades. Also discussed in this review are high-molecular-weight polysaccharides or polysaccharide-protein complexes from mushrooms that appear to enhance innate and cell-mediated immune responses, exhibit antitumor activities in animals and humans, and demonstrate the anticancer properties of selenium compounds accumulated in mushrooms.