Nutritional and botanical modulation of the inflammatory cascade--eicosanoids, cyclooxygenases, and lipoxygenases--as an adjunct in cancer therapy

Molecular Targets of Natural Compounds with Anti-Cancer Properties

Cancer is the second leading cause of death in humans. Despite rapid developments in diagnostic methods and therapies, metastasis and resistance to administrated drugs are the main obstacles to successful treatment. Therefore, the main challenge should be the diagnosis and design of optimal therapeutic strategies for patients to increase their chances of responding positively to treatment and increase their life expectancy. In many types of cancer, a deregulation of multiple pathways has been found. This includes disturbances in cellular metabolism, cell cycle, apoptosis, angiogenesis, or epigenetic modifications. Additionally, signals received from the microenvironment may significantly contribute to cancer development. Chemical agents obtained from natural sources seem to be very attractive alternatives to synthetic compounds. They can exhibit similar anti-cancer potential, usually with reduced side effects. It was reported that natural compounds obtained from fruits and vegetables, e.g., polyphenols, flavonoids, stilbenes, carotenoids and acetogenins, might be effective against cancer cells in vitro and in vivo. Several published results indicate the activity of natural compounds on protein expression by its influence on transcription factors. They could also be involved in alterations in cellular response, cell signaling and epigenetic modifications. Such natural components could be used in our diet for anti-cancer protection. In this review, the activities of natural compounds, including anti-cancer properties, are described. The influence of natural agents on cancer cell metabolism, proliferation, signal transduction and epigenetic modifications is highlighted.

Bromelain, a Group of Pineapple Proteolytic Complex Enzymes (Ananas comosus) and Their Possible Therapeutic and Clinical Effects. A Summary

Bromelain is a complex combination of multiple endopeptidases of thiol and other compounds derived from the pineapple fruit, stem and/or root. Fruit bromelain and stem bromelain are produced completely distinctly and comprise unique compounds of enzymes, and the descriptor “Bromelain” originally referred in actuality to stem bromelain. Due to the efficacy of oral administration in the body, as a safe phytotherapeutic medication, bromelain was commonly suited for patients due to lack of compromise in its peptidase efficacy and the absence of undesired side effects. Various in vivo and in vitro studies have shown that they are anti-edematous, anti-inflammatory, anti-cancerous, anti-thrombotic, fibrinolytic, and facilitate the death of apoptotic cells. The pharmacological properties of bromelain are, in part, related to its arachidonate cascade modulation, inhibition of platelet aggregation, such as interference with malignant cell growth; anti-inflammatory action; fibrinolytic activity; skin debridement properties, and reduction of the severe effects of SARS-Cov-2. In this paper, we concentrated primarily on the potential of bromelain’s important characteristics and meditative and therapeutic effects, along with the possible mechanism of action.

Chemical Characterization and Anti-Inflammatory Activity of Phytoconstituents from Swertia alata

Swertia alata C.B Clarke (Gentianaceae) is a well-reported plant in the traditional system of medicine. The present study was intended to isolate the phytoconstituents from the ethanolic extract of the aerial parts of S. alata; and evaluate for in vitro COX-1/COX-2 inhibition activity, in vivo anti-inflammatory and ulcerogenic activity. Phytoisolation involved partitioning of S. alata ethanolic extract into petroleum ether and chloroform soluble fractions using silica gel-based column chromatography. The isolation afforded two phytoisolates, namely oleanolic acid (SA-1) and 3-hydroxylup-12-(13)-ene-17-carboxylic acid (SA-4). Phytoisolates structures were established by melting point, ultraviolet (UV), attenuated total reflection-Fourier-transform infrared (ATR-FTIR), nuclear magnetic resonance (1H-NMR, 13C-NMR and HMBC) and mass spectrometry. Phytoisolates were further evaluated for in vitro cyclooxygenase (COX-1/COX-2) inhibitory activity, in vivo anti-inflammatory and ulcerogenic activity. The study revealed SA-4 (COX-1/COX-2 inhibition activity of 104/61.68 µM with % inhibition of 61.36) to be more effective than SA-1 (COX-1/COX-2 inhibition activity of 128.4/87.25 µM, with % inhibition of 47.72). SA-1 and SA-4, when subjected to ulcerogenic study, exhibited significant gastric tolerance. The current study reports chromatographic isolation and spectrometric characterization of SA-1 and SA-4. The present study concludes that compound SA-4 possess significant anti-inflammatory activity and less irritant property over gastric mucosa with no significant ulcerogenicity in comparison to indomethacin.

The combination of bromelain and curcumin as an immune-boosting nutraceutical in the prevention of severe COVID-19

The coronavirus disease 2019 (COVID-19) pandemic is still ongoing, while no treatment has been proven effective. COVID-19 pathophysiology involves the activation of three main pathways: the inflammatory, the coagulation and the bradykinin cascades. Here, we highlight for the first time the joint potential therapeutic role of bromelain and curcumin, two well-known nutraceuticals, in the prevention of severe COVID-19. Bromelain (a cysteine protease isolated from the pineapple stem) and curcumin (a natural phenol found in turmeric) exert important immunomodulatory actions interfering in the crucial steps of COVID-19 pathophysiology. Their anti-inflammatory properties include inhibition of transcription factors and subsequent downregulation of proinflammatory mediators. They also present fibrinolytic and anticoagulant properties. Additionally, bromelain inhibits cyclooxygenase and modulates prostaglandins and thromboxane, affecting both inflammation and coagulation, and also hydrolyzes bradykinin. Interestingly, curcumin has been shown in silico studies to prevent entry of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into cells as well as viral replication, while a recent experimental study has demonstrated that bromelain may also inhibit viral entry into cells. Notably, bromelain substantially increases the absorption of curcumin after oral administration. To the best of our knowledge, this is the first report highlighting the significance of bromelain and, most importantly, the potential preventive value of the synergistic effects of bromelain and curcumin against severe COVID-19.

Anti-inflammatory and ulcerogenic activity of newer phytoisolates of Swertia alata C.B. Clarke

The present study was intended to evaluate the in vitro (COX-1/COX-2) and in vivo anti-inflammatory and ulcerogenic activity of newer phytoconstituents isolated from the aerial parts of Swertia alata C.B. Clarke (Gentianaceae). For isolation of newer phytoconstituents, the ethanolic extract of aerial parts of S. alata was subjected to column chromatography using mixture of petroleum ether and chloroform in various concentrations, which yielded two phytoisolates characterised as nonacosyl triacontanoate (SA-3) and 8-O-glucpyranosyl-(2-acetyl)-1,3-dihydroxy-5-methoxy-xanthone (SA-9). Identification of compounds was based on melting point, UV, FTIR, ¹H-NMR, ¹³C-NMR and mass spectrometric data. The isolates were screened for in vitro COX-1/COX-2 inhibitory activity, in vivo anti-inflammatory and ulcerogenic activity. Among the two compounds, SA-3 was found to be more effective than SA-9. The ulcerogenic study revealed significant gastric tolerance of SA-3 and SA-9 in comparison to indomethacin.

Linoleic acid supplementation of cell culture media influences the phospholipid and lipid profiles of human reconstructed adipose tissue

Reconstructed human adipose tissues represent novel tools available to perform in vitro pharmaco-toxicological studies. We used adipose-derived human stromal/stem cells to reconstruct, using tissue engineering techniques, such an adipose tridimensional model. To determine to what extent the in vitro model is representative of its native counterpart, adipogenic differentiation, triglycerides accumulation and phospholipids profiles were analysed. Ingenuity Pathway Analysis software revealed pathways enriched with differentially-expressed genes between native and reconstructed human adipose tissues. Interestingly, genes related to fatty acid metabolism were downregulated in vitro, which could be explained in part by the insufficient amount of essential fatty acids provided by the fetal calf serum used for the culture. Indeed, the lipid profile of the reconstructed human adipose tissues indicated a particular lack of linoleic acid, which could interfere with physiological cell processes such as membrane trafficking, signaling and inflammatory responses. Supplementation in the culture medium was able to influence the lipid profile of the reconstructed human adipose tissues. This study demonstrates the possibility to directly modulate the phospholipid profile of reconstructed human adipose tissues. This reinforces its use as a relevant physiological or pathological model for further pharmacological and metabolic studies of human adipose tissue functions.

Triumph and tumult of matrix metalloproteinases and their crosstalk with eicosanoids in cancer

Cancer development and metastasis are associated to perturbation in metabolic functions of tumor cells and surrounding inflammatory and stromal cell responses. Eicosanoids and lipid mediators, in this regard, attract potential attention during cancer development. Eicosanoids, which include prostaglandin, prostacyclin, thromboxane, and leukotriene, are synthesized from arachidonic acid when cells are stimulated by stress, cytokines, or other growth factors. However, the underlying mechanism of eicosanoids in cancer development, specially their interactions with proto-oncogene factors in tumor microenvironment, remain unexplored. On the other hand, matrix metalloproteinases (MMPs) are a group of zinc-dependent endopeptidases which are involved in degradation of different extracellular matrix (ECM) proteins. MMPs are associated with different physiological responses, including embryogenesis, vasculogenesis, and cellular remodeling, as well as different disease pathogenesis. Induced MMP responses are especially associated with cancer metastasis and secondary tumor development through proteolytic cleavage of several ECM and non-ECM proteins. Although both eicosanoids and MMPs are involved with cancer progression and metastasis, the interrelation between these two molecules are less explored. The present review discusses relevant studies that connect eicosanoids and MMPs and highlight the crosstalk between them offering novel therapeutic approach in cancer treatment.

Intravenous vitamin C in the supportive care of cancer patients: a review and rational approach

This article reviews intravenous vitamin C (IV C) in cancer care and offers a rational approach to enable medical oncologists and integrative practitioners to safely provide IV C combined with oral vitamin C to patients. The use of IV C is a safe supportive intervention to decrease inflammation in the patient and to improve symptoms related to antioxidant deficiency, disease processes, and side effects of standard cancer treatments. A proposed rationale, together with relevant clinical safety considerations for the application of IV C in oncologic supportive care, is provided.

Potential role of bromelain in clinical and therapeutic applications

Pineapple has been used as part of traditional folk medicine since ancient times and it continues to be present in various herbal preparations. Bromelain is a complex mixture of protease extracted from the fruit or stem of the pineapple plant. Although the complete molecular mechanism of action of bromelain has not been completely identified, bromelain gained universal acceptability as a phytotherapeutic agent due to its history of safe use and lack of side effects. Bromelain is widely administered for its well-recognized properties, such as its anti-inflammatory, antithrombotic and fibrinolytic affects, anticancer activity and immunomodulatory effects, in addition to being a wound healing and circulatory improvement agent. The current review describes the promising clinical applications and therapeutic properties of bromelain.

Inflammation as Cause for Scar Cancers of the Lung

The molecular and cellular basis of inflammation has become a topic of great interest of late because of the association between mechanisms of inflammation and risk for cancer. Inflammatory-mediated events, such as the production of reactive oxygen species (ROS), the activation of growth factors (for wound repair), and the altering of signal-transduction processes to activate cell-proliferation (to replace necrotic/apoptotic tissue cells), events that also can occur independently of inflammation, are all considered to be components of risk for a variety of cancers. Using scar cancer of the lung as an example, mechanisms of inflammation associated with recurring infections with Mycobacterium tuberculosisare discussed in the context that they may, in fact, be the major or sole cause of a cancer. Production of ROS, prostaglandins, leukotrienes, and cytokines in pulmonary tissues is greatly enhanced due to a cell-mediated immune response against macrophages infected with M. tuberculosis. These responses lead to the extensive fibrosis associated with recurring infections, possibly leading to decreased clearance of lymph and lymph-associated particles from the infected region. They also will enhance rates of cell division by inhibiting synthesis of P21, leading to enhanced progression from G0 arrest to G1 phase, from G1 to Sphase, and from G2 to M phase of the cell cycle. By increasing rates of oxidative DNA damage and inhibiting apoptosis by enhancing synthesis of BCL-2, mutagenesis of progeny cells is enhanced, and these effects coupled with enhanced angiogenesis stimulated by COX-2 products lead to an environment that is highly conducive to tumorigenesis. Based on the evidence, it appears that but for an inflammatory response to recurring infections, some cases of scar cancer would not exist. By making appropriate lifestyle and dietary changes, a variety of anti-inflammatory effects can be produced, which should attenuate inflammation-induced risk for cancer.

Proteasome inhibitors, including curcumin, improve pancreatic β-cell function and insulin sensitivity in diabetic mice

Background:

Type 2 diabetes stems from obesity-associated insulin resistance, and in the genetically susceptible, concomitant pancreatic β-cell failure can occur, which further exacerbates hyperglycemia. Recent work by our group and others has shown that the natural polyphenol curcumin attenuates the development of insulin resistance and hyperglycemia in mouse models of hyperinsulinemic or compensated type 2 diabetes. Although several potential downstream molecular targets of curcumin exist, it is now recognized to be a direct inhibitor of proteasome activity. We now show that curcumin also prevents β-cell failure in a mouse model of uncompensated obesity-related insulin resistance (Lepr^db/db on the Kaliss background).

Results:

In this instance, dietary supplementation with curcumin prevented hyperglycemia, increased insulin production and lean body mass, and prolonged lifespan. In addition, we show that short-term in vivo treatment with low dosages of two molecularly distinct proteasome inhibitors celastrol and epoxomicin reverse hyperglycemia in mice with β-cell failure by increasing insulin production and insulin sensitivity.

Conclusions:

These studies suggest that proteasome inhibitors may prove useful for patients with diabetes by improving both β-cell function and relieving insulin resistance.

Chemopreventive Effects of Dietary Eicosapentaenoic Acid Supplementation in Experimental Myeloid Leukemia

Current therapies for treatment of myeloid leukemia do not eliminate leukemia stem cells (LSC), leading to disease relapse. In this study, we supplemented mice with eicosapentaenoic acid (EPA, C20:5), a polyunsaturated omega-3 fatty acid, at pharmacologic levels, to examine whether the endogenous metabolite, cyclopentenone prostaglandin delta-12 PGJ3 (Δ(12)-PGJ3), was effective in targeting LSCs in experimental leukemia. EPA supplementation for 8 weeks resulted in enhanced endogenous production of Δ(12)-PGJ3 that was blocked by indomethacin, a cyclooxygenase (COX) inhibitor. Using a murine model of chronic myelogenous leukemia (CML) induced by bone marrow transplantation of BCR-ABL-expressing hematopoietic stem cells, mice supplemented with EPA showed a decrease in the LSC population, and reduced splenomegaly and leukocytosis, when compared with mice on an oleic acid diet. Supplementation of CML mice carrying the T315I mutation (in BCR-ABL) with EPA resulted in a similar effect. Indomethacin blocked the EPA effect and increased the severity of BCR-ABL-induced CML and decreased apoptosis. Δ(12)-PGJ3 rescued indomethacin-treated BCR-ABL mice and decreased LSCs. Inhibition of hematopoietic-prostaglandin D synthase (H-PGDS) by HQL-79 in EPA-supplemented CML mice also blocked the effect of EPA. In addition, EPA supplementation was effective in a murine model of acute myeloid leukemia. EPA-supplemented mice exhibited a decrease in leukemia burden and a decrease in the LSC colony-forming unit (LSC-CFU). The decrease in LSCs was confirmed through serial transplantation assays in all disease models. The results support a chemopreventive role for EPA in myeloid leukemia, which is dependent on the ability to efficiently convert EPA to endogenous COX-derived prostanoids, including Δ(12)-PGJ3.

A randomized clinical trial to determine the efficacy of manufacturers' recommended doses of omega-3 fatty acids from different sources in facilitating cardiovascular disease risk reduction

BACKGROUND

Omega-3 fatty acids confer beneficial health effects, but North Americans are lacking in their dietary omega-3-rich intake. Supplementation is an alternative to consumption of fish; however, not all omega-3 products are created equal. The trial objective was to compare the increases in blood levels of omega-3 fatty acids after consumption of four different omega-3 supplements, and to assess potential changes in cardiovascular disease risk following supplementation.

METHODS

This was an open-label, randomized, cross-over study involving thirty-five healthy subjects. Supplements and daily doses (as recommended on product labels) were:Concentrated Triglyceride (rTG) fish oil: EPA of 650 mg, DHA of 450 mgEthyl Ester (EE) fish oil: EPA of 756 mg, DHA of 228 mgPhospholipid (PL) krill oil: EPA of 150 mg, DHA of 90 mgTriglyceride (TG) salmon oil: EPA of 180 mg, DHA of 220 mg.Subjects were randomly assigned to consume one of four products, in random order, for a 28-day period, followed by a 4-week washout period. Subsequent testing of the remaining three products, followed by 4-week washout periods, continued until each subject had consumed each of the products. Blood samples before and after supplementation were quantified for fatty acid analysis using gas chromatography, and statistically analysed using ANOVA for repeated measures.

RESULTS

At the prescribed dosage, the statistical ranking of the four products in terms of increase in whole blood omega-3 fatty acid levels was concentrated rTG fish oil > EE fish oil > triglyceride TG salmon oil > PL krill oil. Whole blood EPA percentage increase in subjects consuming concentrated rTG fish oil was more than four times that of krill and salmon oil. Risk reduction in several elements of cardiovascular disease was achieved to a greater extent by the concentrated rTG fish oil than by any other supplement. Krill oil and (unconcentrated) triglyceride oil were relatively unsuccessful in this aspect of the study.

CONCLUSION

For the general population, the form and dose of omega-3 supplements may be immaterial. However, given these results, the form and dose may be important for those interested in reducing their risk of cardiovascular disease.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01960660.

The Role of Essential Fatty Acids in Human Health

Fatty acid research began about 90 years ago but intensified in recent years. Essential fatty acids (linoleic and α-linolenic) must come from diet. Other fatty acids may come from diet or may be synthesized. Fatty acids are major components of cell membrane structure, modulate gene transcription, function as cytokine precursors, and serve as energy sources in complex, interconnected systems. It is increasingly apparent that dietary fatty acids influence these vital functions and affect human health. While the strongest evidence for influence is found in cardiovascular disease and mental health, many additional conditions are affected. Problematic changes in the fatty acid composition of human diet have also taken place over the last century. This review summarizes current understanding of the pervasive roles of essential fatty acids and their metabolites in human health.

Emerging targets in lipid-based therapy

The use of prostaglandins and NSAIDS in the clinic has proven that lipid mediators and their associated pathways make attractive therapeutic targets. When contemplating therapies involving lipid pathways, several basic agents come to mind. There are the enzymes and accessory proteins that lead to the metabolism of lipid substrates, provided through diet or through actions of lipases, the subsequent lipid products, and finally the lipid sensors or receptors. There is abundant evidence that molecules along this lipid continuum can serve as prognostic and diagnostic indicators and are in fact viable therapeutic targets. Furthermore, lipids themselves can be used as therapeutics. Despite this, the vernacular dialog pertaining to "biomarkers" does not routinely include mention of lipids, though this is rapidly changing. Collectively these agents are becoming more appreciated for their respective roles in diverse disease processes from cancer to preterm labor and are receiving their due appreciation after decades of ground work in the lipid field. By relating examples of disease processes that result from dysfunction along the lipid continuum, as well as examples of lipid therapies and emerging technologies, this review is meant to inspire further reading and discovery.

11β-Hydroxysteroid Dehydrogenase Type II is a Potential Target for Prevention of Colorectal Tumorigenesis

Colorectal cancer (CRC) is a leading cause of cancer death, yet primary prevention remains the best approach to reducing overall morbidity and mortality. There is a clear molecular link between cyclooxygenase-2 (COX-2)-derived prostaglandin E₂ (PGE₂) production and CRC progression. Although selective COX-2 inhibitors as well as non-steroidal anti-inflammatory drugs (NSAIDs) reduce the number and sizes of colonic adenomas, increased cardiovascular risks of selective COX-2 inhibitors and increased gastrointestinal side-effects of NSAIDs limit their use in chemoprevention of CRC. Glucocorticoids induce apoptosis and are endogenous, potent COX-2 inhibitors. Glucocorticoids have been used for the treatment of hematologic malignancies, but not for solid tumors due to adverse side-effects such as immunosuppression and osteoporosis. In tissues, glucocorticoid actions are down-regulated by t y p e 2 1 1 β-hydroxysteroid dehydrogenase (11βHSD2), and inhibition of 11βHSD2 activity will elevate intracellular active glucocorticoid to levels that effectively suppress COX-2 expression. Both COX-2 and 11βHSD2 increase in Apc^+/min mouse intestinal adenomas and human colonic adenomas and either pharmacologic or genetic 11βHSD2 inhibition leads to decreases in COX-2-mediated PGE₂ production in tumors and prevents adenoma formation, tumor growth, and metastasis. 11βHSD2 inhibition may represent a novel approach for CRC chemoprevention by increasing tumor cell intracellular glucocorticoid activity, which in turn inhibits tumor growth by suppressing the COX-2-derived PGE₂ pathway, as well as other pathways, without potential side-effects relating to chronic application of COX-2 inhibitors, NSAIDs and glucocorticoids.

Effect of high-dose intravenous vitamin C on inflammation in cancer patients

BACKGROUND

An inflammatory component is present in the microenvironment of most neoplastic tissues. Inflammation and elevated C-reactive protein (CRP) are associated with poor prognosis and decreased survival in many types of cancer.Vitamin C has been suggested as having both a preventative and therapeutic role in a number of pathologies when administered at much higher-than-recommended dietary allowance levels.Since in vitro studies demonstrated inhibition of pro-inflammatory pathways by millimolar concentrations of vitamin C, we decided to analyze the effects of high dose IVC therapy in suppression of inflammation in cancer patients.

METHODS

45 patients with prostate cancer, breast cancer, bladder cancer, pancreatic cancer, lung cancer, thyroid cancer, skin cancer and B-cell lymphoma were treated at the Riordan Clinic by high doses of vitamin C (7.5 g -50 g) after standard treatments by conventional methods.CRP and tumor markers were measured in serum or heparin-plasma as a routine analysis. In addition, serum samples were collected before and after the IVCs for the cytokine kit tests.

RESULTS

According to our data positive response to treatment, which was demonstrated by measurements of C- reactive protein, was found in 75% of patients and progression of the inflammation in 25% of patients. IVC treatments on all aggressive stage cancer patients showed the poor response of treatment.There was correlation between tumor markers (PSA, CEA, CA27.29 and CA15-3) and changes in the levels of C-reactive protein.Our test of the effect of IVC on pro-inflammatory cytokines demonstrated that inflammation cytokines IL-1α, IL-2, IL-8, TNF-α, chemokine eotaxin and CRP were reduced significantly after treatments.

CONCLUSIONS

The high dose intravenous ascorbic acid therapy affects C-reactive protein levels and pro-inflammation cytokines in cancer patients. In our study, we found that modulation of inflammation by IVC correlated with decreases in tumor marker levels.In summary, our data support the hypothesis that high dose intravenous ascorbate treatments may reduce inflammation in cancer patients. Our results suggest that further investigations into the use of IVC to reduce inflammation in diseases where inflammation is relevant are warranted.

Current nutraceuticals in the management of osteoarthritis: a review

Osteoarthritis (OA) is a progressive degenerative joint disease that has a major impact on joint function and quality of life. Nutraceuticals and dietary supplements derived from herbs have long been used in traditional medicine and there is considerable evidence that nutraceuticals may play an important role in inflammation and joint destruction in OA. We review the biological effects of some medicinal fruits and herbs - pomegranate, green tea, cat's claw, devil's claw, ginger, Indian olibaum, turmeric and ananas - in an attempt to understand the pivotal molecular targets involved in inflammation and the joint destruction process and to summarize their toxicities and efficacy for OA management. So far there is insufficient reliable evidence on the effectiveness of ginger, turmeric and ananas. Pomegranate and green tea only have preclinical evidence of efficacy due to the lack of clinical data. In vivo and clinical studies are required to understand their targets and efficacy in OA. Limited in vitro and in vivo evidence is available for cat's claw and Indian olibaum. More extensive studies are required before long-term controlled trials of whole cat's claw and Indian olibaum extracts, or isolated active compounds, are carried out in patients with OA to determine their long-term efficacy and safety. Devil's claw has not been rigorously tested to determine its antiarthritic potential in in vitro and in vivo models. There is strong clinical evidence of the effectiveness of devil's claw in pain reduction. However, high-quality clinical trials are needed to determine its effectiveness. No serious side effects have been reported for any fruits and herbs. Overall, these studies identify and support the use of nutraceuticals to provide symptomatic relief to patients with OA and to be used as adjunct therapy for OA management. More high-quality trials are needed to provide definitive answers to questions related to their efficacy and safety for OA prevention and/or treatment.

Arachidonic acid metabolism in human prostate cancer

The arachidonic acid pathway is important in the development and progression of numerous malignant diseases, including prostate cancer. To more fully evaluate the role of individual cyclooxygenases (COXs), lipoxygenases (LOXs) and their metabolites in prostate cancer, we measured mRNA and protein levels of COXs and LOXs and their arachidonate metabolites in androgen-dependent (LNCaP) and androgen-independent (PC-3 and DU145) prostate cancer cell lines, bone metastasis-derived MDA PCa 2a and MDA PCa 2b cell lines and their corresponding xenograft models, as well as core biopsy specimens of primary prostate cancer and nonneoplastic prostate tissue taken ex vivo after prostatectomy. Relatively high levels of COX-2 mRNA and its product PGE2 were observed only in PC-3 cells and their xenografts. By contrast, levels of the exogenous 12-LOX product 12-HETE were consistently higher in MDA PCa 2b and PC-3 cells and their corresponding xenograft tissues than were those in LNCaP cells. More strikingly, the mean endogenous level of 12-HETE was significantly higher in the primary prostate cancers than in the nonneoplastic prostate tissue (0.094 vs. 0.010 ng/mg protein, respectively; p=0.019). Our results suggest that LOX metabolites such as 12-HETE are critical in prostate cancer progression and that the LOX pathway may be a target for treating and preventing prostate cancer.

Regulation of inflammation in cancer by eicosanoids

Inflammation in the tumor microenvironment is now recognized as one of the hallmarks of cancer. Endogenously produced lipid autacoids, locally acting small molecule lipid mediators, play a central role in inflammation and tissue homeostasis, and have recently been implicated in cancer. A well-studied group of autacoid mediators that are the products of arachidonic acid metabolism include: the prostaglandins, leukotrienes, lipoxins and cytochrome P450 (CYP) derived bioactive products. These lipid mediators are collectively referred to as eicosanoids and are generated by distinct enzymatic systems initiated by cyclooxygenases (COX 1 and 2), lipoxygenases (5-LOX, 12-LOX, 15-LOXa, 15-LOXb), and cytochrome P450s, respectively. These pathways are the target of approved drugs for the treatment of inflammation, pain, asthma, allergies, and cardiovascular disorders. Beyond their potent anti-inflammatory and anti-cancer effects, non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2 specific inhibitors have been evaluated in both preclinical tumor models and clinical trials. Eicosanoid biosynthesis and actions can also be directly influenced by nutrients in the diet, as evidenced by the emerging role of omega-3 fatty acids in cancer prevention and treatment. Most research dedicated to using eicosanoids to inhibit tumor-associated inflammation has focused on the COX and LOX pathways. Novel experimental approaches that demonstrate the anti-tumor effects of inhibiting cancer-associated inflammation currently include: eicosanoid receptor antagonism, overexpression of eicosanoid metabolizing enzymes, and the use of endogenous anti-inflammatory lipid mediators. Here we review the actions of eicosanoids on inflammation in the context of tumorigenesis. Eicosanoids may represent a missing link between inflammation and cancer and thus could serve as therapeutic target(s) for inhibiting tumor growth.

Chemotherapeutic effects of bioassay-guided extracts of the American cockroach, Periplaneta americana

The organic extract of Periplaneta americana L. (Dictyoptera; Blattidae) has been traditionally used in southwestern China as an alternative medicine against disorders such as hepatitis, trauma, gastric ulcers, burns, and heart disease. The present study describes bioassay-guided purification and chemotherapeutic evaluation of the 60% ethanolic fraction of P americana organic extracts (PAE60). The most effective cytotoxic fraction was determined by way of repeated in vitro screenings against 12 distinct cultured human carcinoma cell lines: Eca 109, BGC823, HO8910, LS174T, CNE, HeLa, K562, PC-3, A549, BEL 7404, HL-60, and KB, followed by in vivo antitumor assays of the lead fraction (PAE60). The complexity of enriched active fraction was qualitatively evaluated using thin layer chromatography. Reconstituted PAE60 was effective at inhibiting HL-60, KB, CNE, and BGC823 cell growth with IC(50) values <20 µg mL-(1). PAE60 reduced tumor growth in S180-bearing immunocompetent mice by 72.62% after 10 days following oral doses of 500 mg kg d-(1) compared with 78.75% inhibition following 40 mg kg d-(1) of cyclophosphamide (CTX). Thymus and spleen indices of S180-bearing mice treated with PAE60 were significantly greater (P < .05) than CTX treatment groups, suggesting potential immunomodulation of antitumor host defenses by PAE60. Antiviral activity was also investigated and PAE60 inhibited herpes simplex type-2 replication (IC(50) = 4.11 ± 0.64 µg mL-(1)) with a selectivity index (CC(50) to IC(50) ratio) of 64.84 in Vero cells but was less effective on type-1 virus (IC(50) of 25.6 ± 3.16 µg mL-(1)). These results support future clinical trials on P. americana as an alternative or complementary medicinal agent.

The phytoestrogen quercetin impairs steroidogenesis and angiogenesis in swine granulosa cells in vitro

Experimental evidence documents that nutritional phytoestrogens may interact with reproductive functions but the exact mechanism of action is still controversial. Since quercetin is one of the main flavonoids in livestock nutrition, we evaluated its possible effects on cultured swine granulosa cell proliferation, steroidogenesis, and redox status. Moreover, since angiogenesis is essential for follicle development, the effect of the flavonoid on Vascular Endothelial Growth Factor output by granulosa cells was also taken into account. Our data evidence that quercetin does not affect granulosa cell growth while it inhibits progesterone production and modifies estradiol 17beta production in a dose-related manner. Additionally, the flavonoid interferes with the angiogenic process by inhibiting VEGF production as well as by altering redox status. Since steroidogenesis and angiogenesis are strictly involved in follicular development, these findings appear particularly relevant, pointing out a possible negative influence of quercetin on ovarian physiology. Therefore, the possible reproductive impact of the flavonoid should be carefully considered in animal nutrition.

Inhibition of lipoxygenases and cyclooxygenases by linoleyl hydroxamic acid: comparative in vitro studies

In this first comparative in vitro study, linoleyl hydroxamic acid (LHA), a simple and stable derivative of linoleic acid, was tested as an inhibitor of several enzymes involved in arachidonic acid metabolism in mammals. The tested enzymes were human recombinant 5-lipoxygenase (h5-LO), porcine leukocyte 12-LO, rabbit reticulocyte 15-LO, ovine cyclooxygenases 1/2 (COX1/COX2), and human microsomal prostaglandin E synthase-1 (mPGES-1). Potato tuber and soybean lipoxygenases (ptLOX and sLOX, respectively) were studied for comparative purposes. LHA inhibited most of the tested enzymes with the exception of mPGES-1. The LHA inhibitory activity increased as follows: mPGES-1 (no inhibition)<<COX1 = COX2<h5-LO = sLOX = ptLOX<12-LO<<15-LO. The IC(50) values for COX1/COX2, h5-LO, 12-LO, and 15-LO were 60, 7, 0.6, and 0.02 muM, respectively. sLOX was the only tested enzyme that was capable of aerobic oxygenation of LHA, producing 13-hydroperoxy-LHA. The enzyme rapidly inactivated during the reaction. Therefore, LHA could be used as an effective LO/LOX inhibitor without affecting COX1/COX2 and mPGES-1. Possible implications of this observation include treating diseases and pathological states that are caused by (or lead to) hyperproduction of LO-derived metabolites, e.g., inflammation, cardiovascular disorders, cancer, asthma, allergies, psoriasis, and stroke.

Effect of altering dietary omega-6/omega-3 fatty acid ratios on prostate cancer membrane composition, cyclooxygenase-2, and prostaglandin E2

PURPOSE

To determine whether altering the dietary content of omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids affects the growth of androgen-sensitive prostate cancer xenografts, tumor membrane fatty acid composition, and tumor cyclooxygenase-2 and prostaglandin E(2) (PGE(2)) levels.

EXPERIMENTAL DESIGN

Individually caged male severe combined immunodeficiency mice were fed isocaloric 20% kcal fat diets with the fat derived either primarily from n-6 fatty acids (n-6 group) or with the fat consisting of n-6 and n-3 fatty acids in a ratio of 1:1 (n-3 group), and injected s.c. with Los Angeles Prostate Cancer 4 (LAPC-4) cells. Tumor volumes and mouse weights were measured weekly, caloric intake was measured 3 days per week, and tumors and serum were harvested at 8 weeks postinjection.

RESULTS

Tumor growth rates, final tumor volumes, and serum prostate-specific antigen levels were reduced in the n-3 group relative to the n-6 group. The n-3 group tumors had decreased proliferation (Ki67 staining) and increased apoptosis (terminal nucleotidyl transferase-mediated nick end labeling staining). In vitro proliferation of LAPC-4 cells in medium containing n-3 group serum was reduced by 22% relative to LAPC-4 cells cultured in medium containing serum from the n-6 group. The n-6/n-3 fatty acid ratios in serum and tumor membranes were lower in the n-3 group relative to the n-6 group. In addition, n-3 group tumors had decreased cyclooxygenase-2 protein and mRNA levels, an 83% reduction in PGE(2) levels, and decreased vascular endothelial growth factor expression.

CONCLUSION

These results provide a sound basis for clinical trials evaluating the effect of dietary n-3 fatty acids from fish oil on tumor PGE(2) and membrane fatty acid composition, and serum and tumor biomarkers of progression in men with prostate cancer.

Students investigating the antiproliferative effects of synthesized drugs on mouse mammary tumor cells

The potential for personalized cancer management has long intrigued experienced researchers as well as the naïve student intern. Personalized cancer treatments based on a tumor's genetic profile are now feasible and can reveal both the cells' susceptibility and resistance to chemotherapeutic agents. In a weeklong laboratory investigation that mirrors current cancer research, undergraduate and advanced high school students determine the efficacy of common pharmacological agents through in vitro testing. Using mouse mammary tumor cell cultures treated with "unknown" drugs historically recommended for breast cancer treatment, students are introduced to common molecular biology techniques from in vitro cell culture to fluorescence microscopy. Student understanding is assessed through laboratory reports and the successful identification of the unknown drug. The sequence of doing the experiment, applying logic, and constructing a hypothesis gives the students time to discover the rationale behind the cellular drug resistance assay. The breast cancer experiment has been field tested during the past 5 yr with more than 200 precollege/undergraduate interns through the Gains in the Education of Mathematics and Science program hosted by the Walter Reed Army Institute of Research.

Biological basis for the use of botanicals in osteoarthritis and rheumatoid arthritis: a review

Osteoarthritis (OA) of the knee and hip is a debilitating disease affecting more women than men and the risk of developing OA increases precipitously with aging. Rheumatoid arthritis (RA), the most common form of inflammatory joint diseases, is a disease of unknown etiology and affects approximately 1% of the population worldwide, and unlike OA, generally involves many joints because of the systemic nature of the disease. Non-steroidal anti-inflammatory drugs (NSAIDs) are the first drugs of choice for the symptomatic treatment of both OA and RA. Because of the risks associated with the use of NSAIDs and other limitations, the use of alternative therapies, such as acupuncture and medicinal herbs, is on the rise and according to reports approximately 60-90% of dissatisfied arthritis patients are likely to seek the option of complementary and alternative medicine (CAM). This paper reviews the efficacy of some of the common herbs that have a history of human use and their anti-inflammatory or antiarthritic properties have been evaluated in animal models of inflammatory arthritis, in studies employing well defined and widely accepted in vitro models that use human chondrocytes/cartilage explants or in clinical trials. Available data suggests that the extracts of most of these herbs or compounds derived from them may provide a safe and effective adjunctive therapeutic approach for the treatment of OA and RA. This, in turn, argues for trials to establish efficacy and optimum dosage of these compounds for treating human inflammatory and degenerative joint diseases.