Involvement of TNF-alpha changes in human cancer development, prevention and palliative care

Breast tumor tissue inflammation but not lobular involution is associated with survival among breast cancer patients in the Multiethnic Cohort

BACKGROUND

This study investigated the association of breast lobular involution status and three inflammatory markers as predictors of survival among breast cancer patients in the Multiethnic Cohort.

METHODS

Lobular involution was evaluated in tissue sections of normal breast tissue and COX-2, TNF-α, and TGF-β proteins were assessed by immunohistochemistry in tumor microarrays. A summary score added the expression levels of the three markers. Cox regression was applied to estimate hazard ratios (HRs) and 95 % confidence intervals (CI) with age as the time metric and adjustment for factors known to affect mortality.

RESULTS

Among 254 women (mean age = 61.7 ± 8.7 years) with pathologic blocks and follow-up information, 54 all-cause and 10 breast cancer-specific deaths were identified after a mean follow-up time of 16.0 ± 3.1 years. For 214 participants, an inflammatory score was available and 157 women had information on lobular involution. Lobular involution was not significantly associated with survival. Expression of both COX-2 and TNF-α were significant predictors of lower survival (p = 0.02 and 0.04), while the association for TGF-β was weaker (p = 0.09). When combined into one overall inflammation score, both intermediate (HR = 2.72; 95 % CI 0.90-8.28) and high (HR = 4.21; 95 % CI 1.51-11.8) scores were associated with higher mortality but only the latter was statistically significant. No significant association with breast cancer-specific mortality was detected.

CONCLUSIONS

These results suggest that strong expression of inflammatory markers in breast tissue predicts a poorer prognosis possibly due to a system-wide state of chronic inflammation.

DNA methylation and hydroxymethylation profiles reveal possible role of highly methylated TLR signaling on Fasciola gigantica excretory/secretory products (FgESPs) modulation of buffalo dendritic cells

BACKGROUND

Excretory/secretory products (ESPs) released by parasites influence the development and functions of host dendritic cells (DCs). However, little is known about changes of DNA (hydroxy)methylation on DC development during Fasciola gigantica infection. The present study aimed to investigate whether F. gigantica ESPs (FgESPs) affects the development and functions of buffalo DCs through altering the DNA (hydroxy)methylation of DCs.

METHODS

Buffalo DCs were prepared from peripheral blood mononuclear cells (PBMCs) and characterized using scanning and transmission electron microscopy (SEM/TEM) and quantitative reverse transcriptional PCR (qRT-RCR). DCs were treated with 200 μg/ml of FgESPs in vitro, following DNA extraction. The DNA methylome and hydroxymethylome were profiled based on (hydroxy)methylated DNA immunoprecipitation sequencing [(h)MeDIP-Seq] and bioinformatics analyses. qRT-RCR was also performed to assess the gene transcription levels of interest.

RESULTS

FgESPs markedly suppressed DC maturation evidenced by morphological changes and downregulated gene expression of CD1a and MHC II. Totals of 5432 and 360 genes with significant changes in the 5-methylcytosine (5-mC) and the 5-hydroxymethylcytosine (5-hmC) levels, respectively, were identified in buffalo DCs in response to FgESPs challenge. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these differentially expressed genes were highly enriched in pathways associated with immune response. Some cancer-related pathways were also indicated. There were 111 genes demonstrating changes in both 5-mC and 5-hmC levels, 12 of which were interconnected and enriched in 12 pathways. The transcription of hypermethylated genes TLR2, TLR4 and IL-12B were downregulated or in a decreasing trend, while the mRNA level of high-hydroxymethylated TNF gene was upregulated in buffalo DCs post-exposure to FgESPs in vitro.

CONCLUSIONS

To our knowledge, the present study provides for the first time a unique genome-wide profile of DNA (hydroxy)methylation for DCs that interact with FgESPs, and suggests a possible mechanism of FgESPs in suppressing DC maturation and functions that are involved in TLR signaling.

Peptic Ulcer Disease: A Brief Review of Conventional Therapy and Herbal Treatment Options

Peptic ulcer is a chronic disease affecting up to 10% of the world's population. The formation of peptic ulcers depends on the presence of gastric juice pH and the decrease in mucosal defenses. Non-steroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori (H. pylori) infection are the two major factors disrupting the mucosal resistance to injury. Conventional treatments of peptic ulcers, such as proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists, have demonstrated adverse effects, relapses, and various drug interactions. On the other hand, medicinal plants and their chemical compounds are useful in the prevention and treatment of numerous diseases. Hence, this review presents common medicinal plants that may be used for the treatment or prevention of peptic ulcers.

Immunotoxicity and Sensitizing Capacity of Metal Compounds Depend on Speciation

Immunotoxicity of metal compounds is an issue of great importance due to the recent industrial application of metals with unknown toxicity on the immune system and the discovery of metal intermediary compounds not sufficiently studied yet. In this report we show results of our study on the immunotoxicity of the following metals: the Platinum group elements (Platinum, Palladium, Rhodium), Titanium and Arsenic. We applied functional and non functional assays and investigated both innate and adaptive immune systems, in particular, cell proliferation, cytokine production by PBMCs and O−2 production by neutrophils. We obtained the following results: only some Ti compounds (Titanocene, Ti ascorbate and Ti oxalate) show immunotoxicity. Trivalent As compounds (Sodium arsenite and tetraphenyl arsonium chloride) are more immunotoxic than the other investigated As compounds. Genotoxicity of Pt group compounds is in the following order: Pt < Rh < Pd. Immunotoxicity of Pt group compounds is in the following order: Pd < Pt < Rh. Lymphocytes and macrophages show a different reaction of neutrophils to metal toxicity. We can conclude that these studies show that metal immunotoxicity depends on speciation. In general speciation provides additional and often essential information in evaluating metal toxicity. However, there are many difficulties in applying speciation in investigating toxico-kinetic aspects to many metals, mainly due to the lack of information about the existence and significance of species and to the lack of analytical methods for measuring species in biological samples.

“In Vitro” Comparative Immune Effects of Different Titanium Compounds

Exposure to Ti compounds is today an occupational and environmental health hazard. Object of this study was to determine “in vitro” effects of different Ti salts on cultured human peripheral blood mononuclear cells (PBMC) proliferation and cytokine release. 10−4 and 10−7 M Ti compounds did not modify spontaneous PBMC proliferation. Ti dioxide (a biocompatible material and sunscreen component) did not exert effects on phytoemagglutinin (PHA) stimulated PBMC proliferation and on PHA stimulated IFN-γ and TNF-α release from PBMC. On the other hand, 10−4 M Ti oxalate (with wide industrial applications) and Ti ascorbate (used mainly in agriculture) inhibited about 70 % the PHA stimulated PBMC proliferation; both these Ti compounds at 10−4 and 10−7 M concentrations significantly inhibited TNF-α release, while only Ti oxalate inhibited that of IFN-γ. Titanocene (used in chemotherapy) did not exert effects on PBMC proliferation but markedly inhibited IFN-γ and TNF-α release. On the whole, this study demonstrates that Ti dioxide is not immunotoxic; Ti oxalate shows marked immunotoxicity; titanocene exerts selective toxicity on cytokine release but not on PBMC proliferation, while Ti ascorbate affects TNF-α release from PBMC but not IFN-γ release. In conclusion, these data show that immunotoxicity of Ti depends on speciation.

EGCG, green tea polyphenols and their synthetic analogs and prodrugs for human cancer prevention and treatment

Cancer-preventive effects of tea polyphenols, especially epigallocatechin-3-gallate (EGCG), have been demonstrated by epidemiological, preclinical, and clinical studies. Green tea polyphenols such as EGCG have the potential to affect multiple biological pathways, including gene expression, growth factor-mediated pathways, the mitogen-activated protein kinase-dependent pathway, and the ubiquitin/proteasome degradation pathway. Therefore, identification of the molecular targets of EGCG should greatly facilitate a better understanding of the mechanisms underlying its anticancer and cancer-preventive activities. Performing structure-activity relationship (SAR) studies could also greatly enhance the discovery of novel tea polyphenol analogs as potential anticancer and cancer-preventive agents. In this chapter, we review the relevant literature as it relates to the effects of natural and synthetic green tea polyphenols and EGCG analogs on human cancer cells and their potential molecular targets as well as their antitumor effects. We also discuss the implications of green tea polyphenols in cancer prevention.

Green tea: nature's defense against malignancies

The current practice of introducing phytochemicals to support the immune system or fight against diseases is based on centuries old traditions. Nutritional support is a recent advancement in the domain of diet-based therapies; green tea and its constituents are one of the important components of these strategies to prevent and cure various malignancies. The anti-carcinogenic and anti-mutagenic activities of green tea were highlighted some years ago suggesting that it could reduce the prevalence of cancer and even provide protection. The pharmacological actions of green tea are mainly attributed to polyphenols that includes epigallocatechin-3-gallate (EGCG), epicatechin, epicatechin-3-gallate, epigallocatechin. Green tea and its components effectively mitigate cellular damage arising due to oxidative stress. Green tea is supposed to enhance humoral and cell-mediated immunity, decreasing the risk of certain cancers, and may have certain advantage in treating inflammatory disorders. Much of the cancer chemopreventive properties of green tea are mediated by EGCG that induces apoptosis and promotes cell growth arrest, by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing nuclear factor kappa-B activation. Besides, it regulates and promotes IL-23 dependent DNA repair and stimulates cytotoxic T cells activities in a tumor microenvironment. It also blocks carcinogenesis by modulating the signal transduction pathways involved in cell proliferation, transformation, inflammation and metastasis. The review is intended to highlight the chemistry of green tea, its antioxidant potential, its immunopotentiating properties and mode of action against various cancer cell lines that showed its potential as a chemopreventive agent against colon, skin, lung, prostate, and breast cancer.

Phytoceuticals: mighty but ignored weapons against Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection causes peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas, for which the pathogenesis of chronic gastric inflammation prevails and provides the pathogenic basis. Since the role of H. pylori infection is promoting carcinogenesis rather than acting as a direct carcinogen, as several publications show, eradication alone cannot be the right answer for preventing H. pylori-associated gastric cancer. Therefore, a non-antimicrobial approach has been suggested to attain microbe-associated cancer prevention through controlling H. pylori-related chronic inflammatory processes and mediators responsible for carcinogenesis. Phytoceutical is a term for plant products that are active on biological systems. Phytoceuticals such as Korean red ginseng, green tea, red wine, flavonoids, broccoli sprouts, garlic, probiotics and flavonoids are known to inhibit H. pylori colonization, decrease gastric inflammation by inhibiting cytokine and chemokine release, and repress precancerous changes by inhibiting nuclear factor-kappa B DNA binding, inducing profuse levels of apoptosis and inhibiting mutagenesis. Even though further unsolved issues are awaited before phytoceuticals are accepted as a standard treatment for H. pylori infection, phytoceuticals can be a mighty weapon for either suppressing or modulating the disease-associated footprints of H. pylori infection.

Molecular mechanism of PPAR in the regulation of age-related inflammation

Evidence from many recent studies has linked uncontrolled inflammatory processes to aging and aging-related diseases. Decreased a nuclear receptor subfamily of transcription factors, peroxisome proliferator-activated receptors (PPARs) activity is closely associated with increased levels of inflammatory mediators during the aging process. The anti-inflammatory action of PPARs is substantiated by both in vitro and in vivo studies that signify the importance of PPARs as major players in the pathogenesis of many inflammatory diseases. In this review, we highlight the molecular mechanisms and roles of PPARalpha, gamma in regulation of age-related inflammation. By understanding these current findings of PPARs, we open up the possibility of developing new therapeutic agents that modulate these nuclear receptors to control various inflammatory diseases such as atherosclerosis, vascular diseases, Alzheimer's disease, and cancer.

5-LOX inhibitor modulates the inflammatory responses provoked by Helicobacter pylori infection

BACKGROUND

Arachidonic acid metabolites have been considered as pivotal mediators in Helicobacter pylori-induced inflammatory response, which are mainly metabolized by two distinct enzymes: cyclooxygenase (COX) and lipoxygenase (LOX). While COX has become well known to play a key role in either carcinogenesis or inflammation related to H. pylori infection, little is known regarding the implication of LOX in H. pylori infection. In this study, we evaluated the roles of 5-LOX and its metabolites in H. pylori-induced host responses and further a potential beneficial action of specific LOX inhibitors against H. pylori infection.

MATERIALS AND METHODS

Expressions of cytosolic phospholipase A(2) (cPLA(2)), COX-2, and 5-LOX after H. pylori infection were evaluated by immunofluorescence staining and Western blotting. Synthesis of LOX metabolites was measured with reversed-phase high-performance liquid chromatography. For analyzing the influence of 5-LOX inhibitors, nordihydroguaiaretic acid (NDGA) and geraniin, on H. pylori-induced inflammatory responses, RNase protection assay and RT-PCR were performed.

RESULTS

H. pylori stimulated the translocation of cPLA(2) from cytoplasm to nucleus and increased the biosynthesis of hydroxyeicosatetraenoic acids (HETEs) as a predominant form of 5S-HETE in gastric epithelium. NDGA exerted a strong suppression activity of H. pylori-induced 5-LOX signaling. The administration of LOX inhibitors was related with down-expression of proinflammatory mediators such as interleukin-8 and tumor necrosis factor-alpha in both H. pylori-infected gastric epithelial cells and macrophage cells.

CONCLUSION

LOX modulation with its specific inhibitors could impose significant anti-inflammatory responses after H. pylori infection, based on the fact that H. pylori infection provoked gastric inflammation through metabolizing arachidonic acid by the 5-LOX pathway.

Helicobacter pylori-secreting protein Tipalpha is a potent inducer of chemokine gene expressions in stomach cancer cells

PURPOSE

Stomach cancer has a high mortality rate in East Asia, and is strongly associated with Helicobacter pylori (H. pylori) infection. H. pylori is known to express chemokine genes in the gastric mucosa, chemokines that are important host immune factors facilitating inflammation and tumor growth. To investigate the mechanism of carcinogenesis in the stomach, it is essential to determine which molecule of H. pylori is involved in induction of chemokines, but this has remained unclear. We previously reported that a tumor necrosis factor-alpha (TNF-alpha) inducing protein (Tipalpha) secreted from H. pylori acts as a tumor promoter in stomach cancer development, and thus started to investigate whether Tipalpha is involved in induction of chemokine genes.

METHODS

Comprehensive gene expression analysis was conducted using DNA microarray and KeyMolnet analyses. The gene expression was quantitatively analyzed by real-time RT-PCR.

RESULTS

Comprehensive and quantitative gene expression analyses revealed that Tipalpha induces gene expression of the chemokines Ccl2, Ccl7, Ccl20, Cxcl1, Cxcl2, Cxcl5 and Cxcl10 extensively and simultaneously in mouse stomach cancer cells, MGT-40. Tipalpha induced high levels of chemokine gene expression, whereas inactive deleted Tipalpha, del-Tipalpha, showed only marginal expression, suggesting a correlation between tumor promotion and chemokine gene expression by Tipalpha. MG-132, a proteasome inhibitor which represses NF-kappaB-activation, inhibited chemokine gene expressions.

CONCLUSION

We report here that Tipalpha of H. pylori gene product is a strong inducer of chemokine gene expressions, providing a new model for stomach cancer development.

The effects of genetic polymorphisms of IL-1 and TNF-A on Helicobacter pylori-induced gastroduodenal diseases in Korea

OBJECTIVE

To evaluate whether or not genetic polymorphism of IL-1B, IL-1RN, and TNF-Alpha is an important factor in the different expression of gastroduodenal diseases after Helicobacter pylori infection.

METHODS

This study consisted of 1360 subjects: control, gastric cancer (GC, intestinal type, and diffuse type), benign gastric ulcer (BGU), duodenal ulcer, and first-degree gastric cancer relative (GCR). IL-1Beta-511 and TNF-A-308 biallelic polymorphism were genotyped by 5' nuclease polymerase chain reaction (PCR) assays, and PCR-restriction fragment length polymorphism (PCR-RFLP). IL-1RN penta-allelic variable number of tandem repeats was genotyped by PCR.

RESULTS

There was no difference in the genetic polymorphism of IL-1Beta-511, IL-1RN and TNF-A in the patients with gastric cancer regardless of H. pylori positivity compared with control. However, the frequencies of IL-1B-511 C/T (OR: 0.5, 95% CI: 0.3-0.7) and T carrier (OR: 0.6, 95% CI: 0.4-0.8) were lower in the H. pylori-positive BGU patients. The IL-1RN 2/2 was higher (OR: 5.5, 95% CI: 1.1-28.5) in the H. pylori-positive GCR. There was no significance in the polymorphism of TNF-Alpha-308 regardless of H. pylori-induced gastroduodenal diseases.

CONCLUSIONS

The IL-1Beta-511 T-carrier polymorphism has a negative effect on the development of H. pylori-positive BGU, and high frequency of IL-1RN 2/2 was found in the H. pylori-positive relatives of GC patients, which suggest that this genetic polymorphism could play some role in the H. pylori-induced gastroduodenal diseases in Korea.

Presence of a motif conserved between Helicobacter pylori TNF-alpha inducing protein (Tipalpha) and penicillin-binding proteins

Here we report a primary structure conserved between Helicobacter pylori (H. pylori)-tumor necrosis factor-alpha inducing protein (Tipalpha) and bacterial penicillin-binding proteins. H. pylori is a Gram-negative bacterium which plays a key part in carcinogenesis in the human stomach. We previously reported that Tipalpha has a carcinogenic potential as tumor promoter, and that it has no obvious homologue in other species. To investigate the structure-function relationship of Tipalpha and to predict its ancestral protein, we searched among proteins which have weak homology to Tipalpha in their primary structures, using Psi-Blast, and we identified numerous Gram-positive bacterial penicillin-binding proteins as weakly homologous to Tipalpha. Among these, several unique amino acids are conserved and form a motif-like structure. Phylogenic tree analysis indicated that Tipalpha is closer to the penicillin-binding proteins of Gram-positive bacteria, based on their primary structures, than to H. pylori. This finding suggests that Tipalpha and penicillin-binding proteins are derived from a common ancestral protein, and that Tipalpha gene may be transferred horizontally from Gram-positive bacteria to H. pylori.

Apoptosis and production of TNF-alpha by tumor-associated inflammatory cells in histological grade III breast cancer

Tumor necrosis factor alpha (TNF-alpha) is a cytokine that acts as an important mediator of the apoptotic process that also demonstrates selective citotoxicity against malignant breast tumor cells. In the present study, the presence of apoptotic tumor cells and the synthesis of TNF-alpha by inflammatory cells were investigated in tissue samples from grade III invasive breast cancer with long-term follow-up. In situ detection of tumor apoptotic cells was investigated by direct immuno-peroxidase of digoxigenin-labeled genomic DNA. The production of TNF-alpha and tumor cell proliferation were investigated by immunohistochemical procedures. Our data demonstrated that patients with a clinical history of cancer recurrence and metastasis presented a lower number of cancerous apoptotic cells, higher tumor proliferation rates, and lower TNF-alpha expression rates by inflammatory cells than what is observed among patients diagnosed with the same histopathological breast cancer type but in the absence of tumor recurrence and metastasis.

New tumor necrosis factor-alpha-inducing protein released from Helicobacter pylori for gastric cancer progression

PURPOSE

To investigate the association between Helicobacter pylori infection and its inflammatory reaction in gastritis, gastric ulcer, and gastric cancer, a new tumor necrosis factor-alpha (TNF-alpha)-inducing protein of H. pylori was studied.

METHODS

The HP0596 gene of H. pylori was identified as the TNF-alpha-inducing protein (Tipalpha) gene from genome sequence of H. pylori strain 26695. Using recombinant Tipalpha (rTipalpha) and deleted Tipalpha (rdel-Tipalpha) proteins, the latter of which lacks six amino acids containing two cysteines in the N-terminal domain, we examined their activities in TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 (v-H-ras transfected BALB/3T3) cells and mouse gastric epithelial cell line MGT-40, and in vitro transformation of Bhas 42 cells.

RESULTS

Tipalpha protein as a homodimer form (38 kDa) was found in both extracts and culture medium of various H. pylori strains. rTipalpha significantly induced TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 cells and MGT-40, and induced in vitro transformation of Bhas 42 cells. However, rdel-Tipalpha did not. Treatment with MG-132, a proteasome inhibitor, inhibited translocation of NF-kappaB p65, and abrogated TNF-alpha induction induced by Tipalpha protein.

CONCLUSION

Tipalpha is a new carcinogenic factor released from H. pylori mediated through NF-kappaB activation.

New tumor necrosis factor-alpha-inducing protein released from Helicobacter pylori for gastric cancer progression

PURPOSE

To investigate the association between Helicobacter pylori infection and its inflammatory reaction in gastritis, gastric ulcer, and gastric cancer, a new tumor necrosis factor-alpha (TNF-alpha)-inducing protein of H. pylori was studied.

METHODS

The HP0596 gene of H. pylori was identified as the TNF-alpha-inducing protein (Tipalpha) gene from genome sequence of H. pylori strain 26695. Using recombinant Tipalpha (rTipalpha) and deleted Tipalpha (rdel-Tipalpha) proteins, the latter of which lacks six amino acids containing two cysteines in the N-terminal domain, we examined their activities in TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 (v-H-ras transfected BALB/3T3) cells and mouse gastric epithelial cell line MGT-40, and in vitro transformation of Bhas 42 cells.

RESULTS

Tipalpha protein as a homodimer form (38 kDa) was found in both extracts and culture medium of various H. pylori strains. rTipalpha significantly induced TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 cells and MGT-40, and induced in vitro transformation of Bhas 42 cells. However, rdel-Tipalpha did not. Treatment with MG-132, a proteasome inhibitor, inhibited translocation of NF-kappaB p65, and abrogated TNF-alpha induction induced by Tipalpha protein.

CONCLUSION

Tipalpha is a new carcinogenic factor released from H. pylori mediated through NF-kappaB activation.

Immunomodulating Effects of CKBM on the Cytokine Production in Peripheral Blood Mononuclear Cells (PBMCs) from Healthy Volunteers

The current study investigated the immunomodulating effect of CKBM on cytokine induction in peripheral blood mononuclear cells (PBMCs) isolated from 20 healthy volunteers. Cytometric Bead Analysis (CBA) was used to study IL-2, IL-4, IL-6, IL-10, TNF-alpha and IFN-gamma. TNF-alpha and IL-6 were significantly increased in a CKBM dose- and time-dependent manner. Flow cytometry analysis showed an increased intracellular staining of IL-6 but not of TNF-alpha in CKBM treated PBMCs. In addition, MTT cell cytotoxicity assay showed that CKBM concentrations below 5% did not significantly affect the metabolic activities of PBMCs. The current study indicated that CKBM may modulate the immune response by inducing the secretions of TNF-alpha and IL-6, which are cytokine mediators of innate immunity and inflammation preparing or "priming" the body to combat diseases.

Carcinogenic potential of tobacco tar-resistant Staphylococcus aureus in buccal cavity

PURPOSE

The effects of cigarette smoking on the association between inflammation and cancer were studied, since some bacteria induce the production of tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine and endogenous tumor promoter, in cells.

METHODS

Bacteria from a gargled solution from the buccal cavity of 20 individuals were cultured in the presence of 4 mg/ml cigarette-smoke condensates. Although cigarette-smoke condensates inhibited growth of Staphylococcus aureus strongly and that of Staphylococcus warneri weakly, tobacco tar-resistant S. aureus and S. warneri were obtained.

RESULTS

One tobacco tar-resistant S. aureus strain (Sa-TA10) induced expression of the TNF-alpha gene in both Bhas 42 cells (v-Ha-ras transfected BALB/3T3 cells) and human lung cancer cell line H226B, while one tobacco tar-resistant S. warneri (Sw-TA75) did not induce it significantly. Moreover, Sa-TA10 induced formation of transformed foci and soft-agar colony in Bhas 42 cells in cooperation with the v-Ha-ras gene. The results suggested that Sa-TA10 has carcinogenic potential, whereas Sw-TA75 does not.

CONCLUSION

These data suggest that tobacco tar-resistant S. aureus, with carcinogenic potential, is present in the buccal cavity of some individuals, and that cigarette smoking simultaneously inhibits growth of most of the bacteria and selects carcinogenic bacteria.

Tryptophan consumption and indoleamines production by peritoneal cavity macrophages

Melatonin has been shown to regulate several immune functions, and some authors showed that leukocytes are also able to produce the indolamine. In fact, it seems to take part in some immunoregulatory axis, including that related to interferon (IFN) production. So, we evaluated the rate of tryptophan consumption and melatonin and serotonin production in peritoneal cavity-isolated macrophages and the effect of IFN-alpha and -gamma, lipopolysaccharide (LPS), and phorbol myristate acetate (PMA) on such parameters. Our results indicate that macrophages obtained from the peritoneal cavity of normal rats when incubated with tryptophan show an increase in arylalkylamine N-acetyltransferase activity that corresponds to an increased melatonin production, as determined in the incubation medium. This process is regulated by IFN-alpha and -gamma, PMA, LPS, and the serum from tumor-bearing rats, opening the possibility of speculation about different immunoregulatory loops acting through the balance of melatonin/serotonin production by such cells.