Expression of Toll-like receptor 4 in the prostate gland and its association with the severity of prostate cancer

Toll-like receptor (TLR) 4 is a potent prognostic factor in prostate cancer associated with proliferation and invasion

Prostate cancer is one of the most common malignancies in men, and there is a need to explore novel biomarkers or therapeutic targets. Toll-like receptor 4 (TLR4) is expressed not only in antigen-presenting cells but also types of human malignancies, contributing to disease progression, although its clinical significance or functional role in prostate cancer remains unclear. Therefore, we immunolocalized TLR4 in 117 prostate cancer tissues to address its clinicopathological significance. Additionally, we performed in vitro assays to examine the effects of TLR4 on proliferation and migration of prostate cancer cell lines (LNCaP, DU-145 and PC-3). TLR4 immunoreactivity was predominantly detected in the cytoplasm of prostate cancer cells, and it was positively associated with proliferation and invasion abilities, as well as Gleason score. Subsequent in vitro experiments revealed that the inhibition of TLR4 by Sparstolonin B (SsnB) significantly suppressed the proliferation and migration of LNCaP, DU-145 and PC-3 cells. Therefore, we concluded that TLR4 was a potent prognostic factor associated with proliferation and invasion, and it might serve as a therapeutic target in prostate cancer.

Current Trends and Challenges of Microbiome Research in Prostate Cancer

PURPOSE OF REVIEW

The role of the gut microbiome in prostate cancer is an emerging area of research interest. However, no single causative organism has yet been identified. The goal of this paper is to examine the role of the microbiome in prostate cancer and summarize the challenges relating to methodology in specimen collection, sequencing technology, and interpretation of results.

RECENT FINDINGS

Significant heterogeneity still exists in methodology for stool sampling/storage, preservative options, DNA extraction, and sequencing database selection/in silico processing. Debate persists over primer choice in amplicon sequencing as well as optimal methods for data normalization. Statistical methods for longitudinal microbiome analysis continue to undergo refinement. While standardization of methodology may help yield more consistent results for organism identification in prostate cancer, this is a difficult task due to considerable procedural variation at each step in the process. Further reproducibility and methodology research is required.

The human microbiome and benign prostatic hyperplasia: Current understandings and clinical implications

The research of the human microbiome in the preceding decade has yielded novel perspectives on human health and diseases. Benign prostatic hyperplasia (BPH) is a common disease in middle-aged and elderly males, which negatively affects the life quality. Existing evidence has indicated that the human microbiome, including urinary, intra-prostate, gut, oral and blood microbiome may exert a significant impact on the natural progression of BPH. The dysbiosis of the microbiome may induce inflammation at either a local or systemic level, thereby affecting the BPH. Moreover, metabolic syndrome (MetS) caused by the microbiome can also be involved in the development of BPH. Additionally, alterations in the microbiome composition during the senility process may serve as another cause of the BPH. Here, we summarize the influence of human microbiome on BPH and explore how the microbiome is linked to BPH through inflammation, MetS, and senility. In addition, we propose promising areas of investigation and discuss the implications for advancing therapeutic approaches.

Exploring the role of the inflammasomes on prostate cancer: Interplay with obesity

Obesity is a weight-related disorder characterized by excessive adipose tissue growth and dysfunction which leads to the onset of a systemic chronic low-grade inflammatory state. Likewise, inflammation is considered a classic cancer hallmark affecting several steps of carcinogenesis and tumor progression. In this regard, novel molecular complexes termed inflammasomes have been identified which are able to react to a wide spectrum of insults, impacting several metabolic-related disorders, but their contribution to cancer biology remains unclear. In this context, prostate cancer (PCa) has a markedly inflammatory component, and patients frequently are elderly individuals who exhibit weight-related disorders, being obesity the most prevalent condition. Therefore, inflammation, and specifically, inflammasome complexes, could be crucial players in the interplay between PCa and metabolic disorders. In this review, we will: 1) discuss the potential role of each inflammasome component (sensor, molecular adaptor, and targets) in PCa pathophysiology, placing special emphasis on IL-1β/NF-kB pathway and ROS and hypoxia influence; 2) explore the association between inflammasomes and obesity, and how these molecular complexes could act as the cornerstone between the obesity and PCa; and, 3) compile current clinical trials regarding inflammasome targeting, providing some insights about their potential use in the clinical practice.

Histone deacetylase inhibitor sodium butyrate regulates the activation of toll-like receptor 4/interferon regulatory factor-3 signaling pathways in prostate cancer cells

CONTEXT

The covalent acetylation and deacetylation of histone proteins by the histone deacetylase (HDAC) enzymes can be considered a novel therapeutic target in prostate cancer (PCa) cells. Sodium butyrate (NaBu) is a HDAC inhibitor (HDACi) which is a promising potential anticancer drug. Toll-like receptor 4 (TLR4) expression is increased in PCa cells and HDACi alter TLR-inducible gene expressions.

AIMS

We aimed to evaluate the effects of NaBu on TLR4 mediating signaling pathways in two different PCa cells (DU-145 and LNCaP) for the first time.

SUBJECTS AND METHODS

The cytotoxic and apoptotic effects of NaBu were determined by the water-soluble tetrazolium salt (WST-1) and Annexin V-AO/PI assays, respectively. Subcellular localization of TLR4, interferon regulatory factor-3 (IRF3) and Nuclear factor kappa B proteins was evaluated by IF assay.

STATISTICAL ANALYSIS USED

All data were statistically analyzed by GraphPad Prism software (V60.1, CA). Obtained data were expressed in a mean ± standard deviation of the three repeated experiments. The differences between control and NaBu treated cells were compared by one-way-ANOVA. P < 0.05 value was considered statistically significant.

RESULTS

Our results showed that NaBu significantly inhibited the viability of PCa cells and increased the percentage of apoptotic cells. However, DU-145 cells were more sensitive to NaBu than LNCaP cells. Furthermore, NaBu can induce the cytoplasmic TLR4 and IRF3 expression in particularly DU-145 cells without affecting nuclear translocation of NF-kB in PCa cells.

CONCLUSIONS

NaBu induces apoptotic cell death and regulated the TLR4/IRF3 signaling pathways in DU-145 cells but not in LNCaP cells. Therefore, PCa cells differentially responded to NaBu treatment due to probably androgen receptor status.

Oral squamous cell carcinoma (OSCC) tumors from heavy alcohol consumers are associated with higher levels of TLR9 and a particular immunophenotype: Impact on patient survival

Oral squamous cell carcinoma (OSCC) is one of the most frequent types of oral cancer in developing countries and its burden correlates with exposure to tobacco and excessive alcohol consumption. Toll like receptors (TLRs) are major sensors of inflammatory stimuli, from both microbial and sterile causes and as such, they have been related to tumor progression and metastasis. Here, we evaluated the expression of TLR2, 4 and 9 as well as CD3+, CD8+ and Granzyme B+ cell infiltration by immunohistochemistry in oral samples of 30 patients with OSCC, classified according to their consumption of alcohol. Our findings indicate that there is a significant association between heavy alcohol consumption and tumors with higher expression levels of TLR9. Moreover, patients with TLR9high tumors, as well as those who indicated high consumption of alcohol exhibited a diminished overall survival. TCGA data analysis indicated that TLR9high tumors express a significant increase in some genes related with the oral cavity itself, inflammation and tumor promotion. Our analysis of tumor infiltrating leukocytes demonstrated that the major differences perceived in heavy alcohol consumers was the location of CD8+ T cells infiltrating the tumor, which showed lower numbers intratumorally. Our data suggest the existence of a pathogenic loop that involves alcohol consumption, high TLR9 expression and the immunophenotype, which might have a profound impact on the progression of the disease.

Inhibition of TLR7 and TLR9 Reduces Human Cholangiocarcinoma Cell Proliferation and Tumor Development

BACKGROUND

Toll-like receptors (TLRs) are key players in innate immunity and modulation of TLR signaling has been demonstrated to profoundly affect proliferation and growth in different types of cancer. However, the role of TLRs in human intrahepatic cholangiocarcinoma (ICC) pathogenesis remains largely unexplored.

AIMS

We set out to determine if TLRs play any role in ICCs which could potentially make them useful treatment targets.

METHODS

Tissue microarrays containing samples from 9 human ICCs and normal livers were examined immunohistochemically for TLR4, TLR7, and TLR9 expression. Proliferation of human ICC cell line HuCCT1 was measured by MTS assay following treatment with CpG-ODN (TLR9 agonist), imiquimod (TLR7 agonist), chloroquine (TLR7 and TLR9 inhibitor) and IRS-954 (TLR7 and TLR9 antagonist). The in vivo effects of CQ and IRS-954 on tumor development were also examined in a NOD-SCID mouse xenograft model of human ICC.

RESULTS

TLR4 was expressed in all normal human bile duct epithelium but absent in the majority (60%) of ICCs. TLR7 and TLR9 were expressed in 80% of human ICCs. However, TLR7 was absent in all cases of normal human bile duct epithelium and only one was TLR9 positive. HuCCT1 cell proliferation in vitro significantly increased following IMQ or CpG-ODN treatment (P < 0.03 and P < 0.002, respectively) but decreased with CQ (P < 0.02). In the mouse xenograft model there was significant reduction in size of tumors from CQ and IRS-954 treated mice compared to untreated controls.

CONCLUSION

TLR7 and TLR9 should be further explored for their potential as actionable targets in the treatment of ICC.

High IRF8 expression correlates with CD8 T cell infiltration and is a predictive biomarker of therapy response in ER-negative breast cancer

Background

Characterization of breast cancer (BC) through the determination of conventional markers such as ER, PR, HER2, and Ki67 has been useful as a predictive and therapeutic tool. Also, assessment of tumor-infiltrating lymphocytes has been proposed as an important prognostic aspect to be considered in certain BC subtypes. However, there is still a need to identify additional biomarkers that could add precision in distinguishing therapeutic response of individual patients. To this end, we focused in the expression of interferon regulatory factor 8 (IRF8) in BC cells. IRF8 is a transcription factor which plays a well-determined role in myeloid cells and that seems to have multiple antitumoral roles: it has tumor suppressor functions; it acts downstream IFN/STAT1, required for the success of some therapeutic regimes, and its expression in neoplastic cells seems to depend on a cross talk between the immune contexture and the tumor cells.

The goal of the present study was to examine the relationship between IRF8 with the therapeutic response and the immune contexture in BC, since its clinical significance in this type of cancer has not been thoroughly addressed.

Methods

We identified the relationship between IRF8 expression and the clinical outcome of BC patients and validated IRF8 as predictive biomarker by using public databases and then performed in silico analysis. To correlate the expression of IRF8 with the immune infiltrate in BC samples, we performed quantitative multiplex immunohistochemistry.

Results

IRF8 expression can precisely predict the complete pathological response to monoclonal antibody therapy or to select combinations of chemotherapy such as FAC (fluorouracil, adriamycin, and cytoxan) in ER-negative BC subtypes. Analysis of immune cell infiltration indicates there is a strong correlation between activated and effector CD8⁺ T cell infiltration and tumoral IRF8 expression.

Conclusions

We propose IRF8 expression as a potent biomarker not only for prognosis, but also for predicting therapy response in ER-negative BC phenotypes. Its expression in neoplastic cells also correlates with CD8⁺ T cell activation and infiltration. Therefore, our results justify new efforts towards understanding mechanisms regulating IRF8 expression and how they can be therapeutically manipulated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01418-7.

Assessment of TLR4 and TLR9 signaling and correlation with human papillomavirus status and histopathologic parameters in oral tongue squamous cell carcinoma

OBJECTIVES

Toll-like receptors (TLRs) may promote or inhibit tumor progression. The aim of this study was to assess the expression of TLR4 and TLR9 and their downstream targets in oral tongue squamous cell carcinoma (OTSCC) in correlation with histopathologic parameters and human papillomavirus (HPV) status.

STUDY DESIGN

OTSCC (fully or superficially invasive and in situ) were studied. Immunohistochemical expression of TLR4, TLR9, nuclear factor-κΒ (NF-κΒ/p65), and interferon-β (IFN-β) was evaluated in tumor and inflammatory cells and in adjacent morphologically normal mucosa. HPV status was also determined.

RESULTS

TLR4 showed increased expression levels in tumor and infiltrating inflammatory cells compared with adjacent mucosa, especially in fully invasive cases; a negative correlation between TLR4 levels in inflammatory cells and tumor grade was observed. TLR9 was upregulated in tumor and infiltrating inflammatory cells compared with the adjacent mucosa; its expression in inflammatory cells was higher in well differentiated tumors. NF-κΒ and IFN-β were elevated in cancerous tissues, especially in fully invasive cases, and positively correlated with TLR4 and/or TLR9. HPV positivity (detected in 15.9% of the cases) demonstrated positive correlation with TLR9 and NF-κΒ levels.

CONCLUSIONS

TLR4 and TLR9 are upregulated in OTSCC and its microenvironment and, by affecting important downstream molecules, such as NF-κB and IFN-β, may play a role in oral cancer development and progression.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.

TLR4 Polymorphisms and Expression in Solid Cancers

Toll-like receptors (TLRs) are a type of pattern-recognition receptor (PRR) that are part of the innate immune system known to recognize pathogen-associated molecular patterns and thereby play a crucial role in host immune response. Among the various known TLRs, TLR4 is one of the most extensively studied PRRs expressed by immune, certain nonimmune, and tumor cells. When TLR4 binds with the bacterial lipopolysaccharide, it induces production of proinflammatory cytokines, chemokines, and effector molecules as part of the immune response. Continuous exposure to pathogens and TLR4 signaling results in chronic inflammation that may further lead to malignant transformation. TLR4 is a highly polymorphic gene, and genetic variations are known to influence host immune response, leading to dysregulation of signaling pathway, which may affect an individual's susceptibility to various diseases, including cancer. Furthermore, TLR4 expression in different tumor types may also serve as a marker for tumor proliferation, differentiation, metastasis, prognosis, and patient survival. This review aims to summarize various reports related to TLR4 polymorphisms and expression patterns and their influences on different cancer types with a special focus on solid tumors.

Growth hormone-releasing hormone antagonists reduce prostatic enlargement and inflammation in carrageenan-induced chronic prostatitis

BACKGROUND

Inflammation plays a key role in the etiology of benign prostatic hyperplasia (BPH) through multiple pathways involving the stimulation of proliferation by cytokines and growth factors as well as the induction of the focal occurrence of epithelial-to-mesenchymal transition (EMT). We have previously reported that GHRH acts as a prostatic growth factor in experimental BPH and in autoimmune prostatitis models and its blockade with GHRH antagonists offer therapeutic approaches for these conditions. Our current study was aimed at the investigation of the beneficial effects of GHRH antagonists in λ-carrageenan-induced chronic prostatitis and at probing the downstream molecular pathways that are implicated in GHRH signaling.

METHODS

To demonstrate the complications triggered by recurrent/chronic prostatic inflammation in Sprague-Dawley rats, 50 μL 3% carrageenan was injected into both ventral prostate lobes two times, 3 weeks apart. GHRH antagonist, MIA-690, was administered 5 days after the second intraprostatic injection at 20 μg daily dose for 4 weeks. GHRH-induced signaling events were identified in BPH-1 and in primary prostate epithelial (PrEp) cells at 5, 15, 30, and 60 min with Western blot.

RESULTS

Inflammation induced prostatic enlargement and increased the area of the stromal compartment whereas treatment with the GHRH antagonist significantly reduced these effects. This beneficial activity was consistent with a decrease in prostatic GHRH, inflammatory marker COX-2, growth factor IGF-1 and inflammatory and EMT marker TGF-β1 protein levels and the expression of multiple genes related to EMT. In vitro, GHRH stimulated multiple pathways involved in inflammation and growth in both BPH-1 and PrEp cells including NFκB p65, AKT, ERK1/2, EGFR, STAT3 and increased the levels of TGF-β1 and Snail/Slug. Most interestingly, GHRH also stimulated the transactivation of the IGF receptor.

CONCLUSIONS

The study demonstrates that GHRH antagonists could be beneficial for the treatment of prostatic inflammation and BPH in part by inhibiting the growth-promoting and inflammatory effects of locally produced GHRH.

Evaluation of the detection of Toll-like receptors (TLRs) in cancer development and progression in patients with colorectal cancer

Background

Toll-like receptors (TLRs) play essential role in innate and acquired immunity, are expressed in various cell types, and are associated with altered susceptibility to many diseases, and cancers. The aim of this study was to investigate TLR2 (-196 to-174del), TLR4 (Asp299Gly and Thr399Ile) and TLR9 (T1237C and T1486C) gene polymorphisms at risk of colorectal cancer (CRC) development and progression.

Methods

Peripheral blood was obtained from 397 patients with adjuvant (stage II/III, n = 202) and metastatic (n = 195) CRC. Moreover, blood samples from 50 healthy volunteers and 40 patients with adenomatous polyps were also included as control groups. DNA from patients and controls was analyzed using PCR and PCR-RFLP for genotyping functional polymorphism within TLR2, TLR4 and TLR9 genotypes.

Results

TLR2–196 to-174del/del genotype was detected in 76.6% of the patients and was significantly higher that the controls groups (p<0.001). TLR4 Asp299Gly, TLR4 Thr399Ile, TLR9 T1237C and T1486C homozygous genotypes were detected in 70.5%, 70.5%, 61.5% and 61.5% of the patients respectively, and were also significantly higher than that in the control groups (p<0.001). All polymorphisms detected were also significantly associated with the metastatic disease (p<0.001) leading to shorter overall survival (p<0.001); whereas, TLR4 Asp299Gly and Thr399Ile polymorphisms were significantly associated with KRAS mutations.

Conclusions

The detection of higher frequencies of the TLR2, TLR4 and/or TLR9 polymorphisms in CRC patients compared with the control groups highlight the role of these polymorphism in CRC development and cancer progression.

The inflammatory microenvironment and microbiome in prostate cancer development

Chronic inflammation promotes the development of several types of solid cancers and might contribute to prostate carcinogenesis. This hypothesis partly originates in the frequent observation of inflammatory cells in the prostate microenvironment of adult men. Inflammation is associated with putative prostate cancer precursor lesions, termed proliferative inflammatory atrophy. Inflammation might drive prostate carcinogenesis via oxidative stress and generation of reactive oxygen species that induce mutagenesis. Additionally, inflammatory stress might cause epigenetic alterations that promote neoplastic transformation. Proliferative inflammatory atrophy is enriched for proliferative luminal epithelial cells of intermediate phenotype that might be prone to genomic alterations leading to prostatic intraepithelial neoplasia and prostate cancer. Studies in animals suggest that inflammatory changes in the prostate microenvironment contribute to reprogramming of prostate epithelial cells, a possible step in tumour initiation. Prostatic infection, concurrent with epithelial barrier disruption, might be a key driver of an inflammatory microenvironment; the discovery of a urinary microbiome indicates a potential source of frequent exposure of the prostate to a diverse number of microorganisms. Hence, current evidence suggests that inflammation and atrophy are involved in prostate carcinogenesis and suggests a role for the microbiome in establishing an inflammatory prostate microenvironment that might promote prostate cancer development and progression.

Characterizing the Association Between Toll-like Receptor Subtypes and Nephrolithiasis With Renal Inflammation in an Animal Model

OBJECTIVE

To show experimentally induced renal stone disease and to evaluate secondary inflammatory responses in vivo, and to characterize changes in the expression of Toll-like receptor (TLR) subtypes in this model.

METHODS

Twenty 5- to 6-week-old male Wistar rats were divided into control and hyperoxaluria groups (n = 10 per group) and were supplied with normal water or 1% ethylene glycol, respectively, for 16 weeks. The animals were then placed in metabolic cages, and urine was collected for a 24-hour urine oxalate level evaluation. Following sacrifice, rats were subjected to bilateral nephrectomy and both kidneys were histopathologically evaluated. A 1-mm³ biopsy section from the right kidney of each rat was subjected to real-time polymerase chain reaction of the TLR expression.

RESULTS

At the end of week 16, the hyperoxaluria group had a higher mean 24-hour urine oxalate level (1.91) than the control group (0.29) (P <.05) and a remarkably increased deposition of renal CaOx crystals (15/20) than the control group (0/20) (P <.05), which was universally accompanied by inflammation (15/15). Twelve and no rats in the hyperoxaluria and control groups, respectively, had macroscopically visible renal pelvic stones (P <.05). Quantitative real-time polymerase chain reaction revealed significant decreases in the expression of several TLRs, particularly TLR11 and TLR7. Decreases in TLR1, TLR3, and TLR6 expressions and an increase in the TLR2 expression did not differ significantly between the groups.

CONCLUSION

We believe that is the first evaluation of TLR expression associated with renal stone formation in an animal model of inflammation. These results might lead to novel TLR-based treatments for nephrolithiasis and related inflammatory renal damage.

Downregulation of adaptor protein MyD88 compromises the angiogenic potential of B16 murine melanoma

The mechanisms that link inflammatory responses to cancer development remain a subject of intense investigation, emphasizing the need to better understand the cellular and molecular pathways that create a tumor promoting microenvironment. The myeloid differentiation primary response protein MyD88 acts as a main adaptor molecule for the signaling cascades initiated from Toll-like receptors (TLRs) and the interleukin 1 receptor (IL-1R). MyD88 has been shown to contribute to tumorigenesis in many inflammation-associated cancer models. In this study, we sought to better define the role of MyD88 in neoplastic cells using a murine melanoma model. Herein, we have demonstrated that MyD88 expression is required to maintain the angiogenic switch that supports B16 melanoma growth. By knocking down MyD88 we reduced TLR-mediated NF-κB activation with no evident effects over cell proliferation and survival. In addition, MyD88 downregulation was associated with a decrease of HIF1α levels and its target gene VEGF, in correlation with an impaired capability to induce capillary sprouting and tube formation of endothelial cells. Melanomas developed from cells lacking MyD88 showed an enhanced secretion of chemoattractant ligands such as CCL2, CXCL10 and CXCL1 and have an improved infiltration of macrophages to the tumor site. Our results imply that cell-autonomous signaling through MyD88 is required to sustain tumor growth and underscore its function as an important positive modulator of tumor angiogenesis.

Androgen regulation of host defenses and response to inflammatory stimuli in the prostate gland

The prostate gland is a strictly androgen-dependent organ which is also the main target of infectious and inflammatory diseases in the male reproductive tract. Host defenses and immunity of the gland have unique features to maintain a constant balance between response and tolerance to diverse antigens. In this context, the effects of reproductive hormones on the male tract are thus complex and have just started to be defined. From the classical description of "the prostatic antibacterial factor," many host defense proteins with potent microbicidal and anti-tumoral activities have been described in the organ. Indeed, it has been proposed a central role for resident cells, that is, epithelial and smooth muscle cells, in the prostatic response against injuries. However, these cells also represent the target of the inflammatory damage, leading to the development of a Proliferative Inflammatory Atrophy-like process in the epithelium and a myofibroblastic-like reactive stroma. Available data on androgen regulation of inflammation led to a model of the complex control, in which the final effect will depend on the tissue microenvironment, the cause of inflammation, and the levels of androgens among other factors. In this paper, we review the current scientific literature about the inflammatory process in the gland, the modulation of host defense proteins, and the influence of testosterone on the resolution of prostatitis.

Decreased expression of Toll-like receptor 4 and 5 during progression of prostate transformation in transgenic adenocarcinoma of mouse prostate mice

Chronic inflammation has been considered an important risk factor for development of prostate cancer. Toll-like receptors (TLRs) recognize microbial moieties or endogenous molecules and play an important role in the triggering and promotion of inflammation. In this study, we examined whether expression of TLR4 and TLR5 was associated with progression of prostate transformation in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. The expression of TLR4 and TLR5 was evaluated by immunohistochemisty in formalin-fixed paraffin-embedded prostate tissue from wild-type (WT) and TRAMP mice. Normal prostate tissue from WT mice showed strong expression of TLR4 and TLR5. However, TLR4 expression in the prostate tissue from TRAMP mice gradually decreased as pathologic grade became more aggressive. TLR5 expression in the prostate tissue from TRAMP mice also decreased in low-grade prostate intraepithelial neoplasia (PIN), high-grade PIN and poorly differentiated adenocarcinoma. Overall, our results suggest that decreased expression of TLR4 and TLR5 may contribute to prostate tumorigenesis.

Tumor progression locus 2 (Tpl2) kinase as a novel therapeutic target for cancer: double-sided effects of Tpl2 on cancer

Tumor progression locus 2 (Tpl2) is a mitogen-activated protein kinase (MAPK) kinase kinase (MAP3K) that conveys various intra- and extra-cellular stimuli to effector proteins of cells provoking adequate adoptive responses. Recent studies have elucidated that Tpl2 is an indispensable signal transducer as an MAP3K family member in diverse signaling pathways that regulate cell proliferation, survival, and death. Since tumorigenesis results from dysregulation of cellular proliferation, differentiation, and apoptosis, Tpl2 participates in many decisive molecular processes of tumor development and progression. Moreover, Tpl2 is closely associated with cytokine release of inflammatory cells, which has crucial effects on not only tumor cells but also tumor microenvironments. These critical roles of Tpl2 in human cancers make it an attractive anti-cancer therapeutic target. However, Tpl2 contradictorily works as a tumor suppressor in some cancers. The double-sided effects of Tpl2 originate from the specific upstream and downstream signaling environment of each tumor, since Tpl2 interacts with various signaling components. This review summarizes recent studies concerning the possible roles of Tpl2 in human cancers and considers its possibility as a therapeutic target, against which novel anti-cancer agents could be developed.

Toll-like receptors and prostate cancer

Prostate cancer is the second leading cause of cancer-related death in men after lung cancer. Immune responses clearly play a critical role in the tumorigenesis and in the efficacy of radiation therapy and chemotherapy in prostate cancer; however, the underlying molecular mechanisms are still poorly understood. Toll-like receptors (TLRs) are a well-known family of pattern recognition receptors that play a key role in host immune system. Recent studies demonstrate that there are links between TLRs and cancer; however, the function and biological importance of TLRs in prostate cancer seems complex. To elucidate the role of TLRs and innate immunity in prostate cancer might provide us with a better understanding of the molecular mechanisms of this disease. Moreover, utilizing the agonists or antagonists of TLRs might represent a promising new strategy against prostate cancer. In this review, we summarize recent advances on the studies of association between TLR signaling and prostate cancer, TLR polymorphisms and prostate cancer risk, and provide some insights about TLRs as potential targets for prostate cancer immunotherapy.

Knockdown of toll-like receptor 4 inhibits human NSCLC cancer cell growth and inflammatory cytokine secretion in vitro and in vivo

Toll-like receptor 4 (TLR4)-mediated signaling has been implicated in tumor cell invasion, survival and metastasis in several types of cancers. However, the expression of TLR4 in patients with non-small cell lung cancer (NSCLC) and its biological function in the development and progression of NSCLC have not been elucidated to date. Here, we sought to characterize the expression of TLR4 in patients with NSCLC and to investigate the biological roles of TLR4 in lung metastasis, cell invasion and survival. In this study, we found that TLR4 expression was elevated in most patients with NSCLC, and its expression levels correlated with key pathological characteristics, including tumor differentiation, stage and metastasis. Our data also showed that downregulation of TLR4 expression using an RNA silencing approach in A549 tumor cells significantly suppressed cell proliferation, cell migration and cell invasion, and induced tumor apoptosis in vitro, and suppressed tumor growth in vivo. In addition, we also found that downregulation of TLR4 expression significantly decreased cell TNF-α and IL-6 levels. Furthermore, we found that knockdown of TLR4 was able to significantly suppress constitutive phosphorylation of Akt and PI3K, which may contribute to the inhibition of tumor growth. These data suggest that TLR4 plays an important role in tumorigenic properties of human NSCLC, and that RNA interference-directed targeting of TLR4 could be used as a potential anticancer therapeutic target in NSCLC.

The double-edged sword: conserved functions of extracellular hsp90 in wound healing and cancer

Heat shock proteins (Hsps) represent a diverse group of chaperones that play a vital role in the protection of cells against numerous environmental stresses. Although our understanding of chaperone biology has deepened over the last decade, the “atypical” extracellular functions of Hsps have remained somewhat enigmatic and comparatively understudied. The heat shock protein 90 (Hsp90) chaperone is a prototypic model for an Hsp family member exhibiting a duality of intracellular and extracellular functions. Intracellular Hsp90 is best known as a master regulator of protein folding. Cancers are particularly adept at exploiting this function of Hsp90, providing the impetus for the robust clinical development of small molecule Hsp90 inhibitors. However, in addition to its maintenance of protein homeostasis, Hsp90 has also been identified as an extracellular protein. Although early reports ascribed immunoregulatory functions to extracellular Hsp90 (eHsp90), recent studies have illuminated expanded functions for eHsp90 in wound healing and cancer. While the intended physiological role of eHsp90 remains enigmatic, its evolutionarily conserved functions in wound healing are easily co-opted during malignancy, a pathology sharing many properties of wounded tissue. This review will highlight the emerging functions of eHsp90 and shed light on its seemingly dichotomous roles as a benevolent facilitator of wound healing and as a sinister effector of tumor progression.

Toll-like receptor 10-1-6 gene cluster polymorphisms are not associated with benign prostatic hyperplasia in korean population

Purpose

Inflammation and infection have been associated with the pathogenesis of benign prostatic hyperplasia (BPH). Toll-like receptors (TLRs) play key roles in the innate immune system and initiate the inflammatory response to foreign pathogens. We investigated the relationship between TLR10-1-6 gene cluster polymorphisms and BPH.

Methods

We genotyped four promoter single nucleotide polymorphisms (SNPs) (TLR10, rs10004195; TLR1, rs5743557; and TLR6, rs1039560 and rs1039559) by directly sequencing (233 BPH patients and 214 control subjects). SNPStats and Haploview version 4.02 were used to analyze the data. Multiple logistic regression models (log-additive, dominant, and recessive) were performed to determine odds ratios (ORs), 95% confidence intervals (CIs), and P-values.

Results

The genotype and allele frequencies of each SNP was not different between the BPH and control groups (P>0.05). Haplotype analysis showed no association between the haplotype in the linkage disequilibrium (LD) block and BPH (P>0.05), although the LD block was constructed.

Conclusions

These results indicate that the TLR10-1-6 gene cluster may be not associated with the development of BPH in the Korean population.

Chlamydia trachomatis infection increases the expression of inflammatory tumorigenic cytokines and chemokines as well as components of the Toll-like receptor and NF-κB pathways in human prostate epithelial cells

Inflammation has been reported to play a major role in prostate carcinogenesis. Several bacterial infections can lead to prostate inflammation; however, until now, the precise molecular and cellular mechanisms linking inflammation to carcinogenesis have remained unclear. We therefore investigated the initiation of inflammation induced by Chlamydia trachomatis (C. trachomatis) infection in human prostate epithelial cells using an in vitro culture system in which human androgen-independent PC-3 prostate cancer epithelial cells were infected with C. trachomatis serovar L2. The expression levels of VEGF, ICAM-1, IL-6, IL-8, IL-1β, TNFα, CCL5, CCL2 and iNOS inflammation-related genes, as well as genes involved in the Toll-like receptor (TLR) pathway (TLR2, TLR4, CD14 and MyD88), were evaluated at the mRNA level in infected PC-3 cells 24 h after infection with C. trachomatis serovar L2. The expression levels of components of the NF-κB pathway (p65 and IκBα) were evaluated at the mRNA level in infected PC-3 cells at different time points (1, 6, 12 and 24 h) after infection. The expression levels of inflammation-related genes, components of the Toll-like receptor pathway and genes involved in NF-κB activation were analyzed in infected and uninfected cells using semi-quantitative RT-PCR. We detected a significant increase (p < 0.001) in inflammation-related cytokines in infected PC-3 cells. During infection, PC-3 cells elicited a proinflammatory response, as shown by NF-κB activation, TLR2 and TLR4 upregulation and the increased expression of inflammation-related genes. Furthermore, we observed significant upregulation of the adhesion molecules ICAM-1 and VEGF, which are two biomarkers correlated with tumor progression and immune system evasion. The present study suggests that human prostate cancer epithelial cells are susceptible to C. trachomatis infection and upregulate proinflammatory markers during infection.

Should a Toll-like receptor 4 (TLR-4) agonist or antagonist be designed to treat cancer? TLR-4: its expression and effects in the ten most common cancers

Toll-like receptor 4 (TLR-4) is well known for its host innate immunity. Despite the fact that TLR-4 activation confers antitumor responses; emerging evidence suggests that TLR-4 is associated with tumor development and progression. It is now clear that overactivation of TLR-4, through various immune mediators, may cause immune response dysfunction, resulting in tumorigenesis. Different cancers could have different extents of TLR-4 involvement during tumorigenesis or tumor progression. In this review, we focus on infection- and inflammation-related TLR-4 activation in noncancer and cancer cells, as well as on the current evidence about the role of TLR-4 in ten of the most common cancers, viz, head and neck cancer, lung cancer, gastrointestinal cancer, liver cancer, pancreatic cancer, skin cancer, breast cancer, ovarian cancer, cervical cancer, and prostate cancer.

Chlamydia trachomatis infection of the male genital tract: an update

Chlamydia trachomatis (CT) is the most prevalent cause of sexually transmitted diseases. Although the prevalence of chlamydial infection is similar in men and women, current research and screening are still focused on women, who develop the most severe complications, leaving the study of male genital tract (MGT) infection underrated. Herein, we reviewed the literature on genital CT infection with special focus on the MGT. Data indicate that CT certainly infects different parts of the MGT such as the urethra, seminal vesicles, prostate, epididymis and testis. However, whether or not CT infection has detrimental effects on male fertility is still controversial. The most important features of CT infection are its chronic nature and the presence of a mild inflammation that remains subclinical in most individuals. Chlamydia antigens and pathogen recognition receptors (PRR), expressed on epithelial cells and immune cells from the MGT, have been studied in the last years. Toll-like receptor (TLR) expression has been observed in the testis, epididymis, prostate and vas deferens. It has been demonstrated that recognition of chlamydial antigens is associated with TLR2, TLR4, and possibly, other PRRs. CT recognition by PRRs induces a local production of cytokines/chemokines, which, in turn, provoke chronic inflammation that might evolve in the onset of an autoimmune process in genetically susceptible individuals. Understanding local immune response along the MGT, as well as the crosstalk between resident leukocytes, epithelial, and stromal cells, would be crucial in inducing a protective immunity, thus adding to the design of new therapeutic approaches to a Chlamydia vaccine.

Immunohistochemical expression of TLR4 and TLR9 in various grades of oral epithelial dysplasia and squamous cell carcinoma, and their roles in tumor progression: a pilot study

Toll-like receptors (TLRs) play an essential role in the activation of innate immunity. TLRs are expressed in B-lymphocytes, monocytes, dendritic cells and epithelial cells. We examined the immunohistochemical expressions of TLR4 and TLR9 in various grades of oral epithelial dysplasia (OED), oral squamous cell carcinoma (OSCC) and normal oral mucosa (NOM) to determine the association between TLR4 and TLR9 in the progression of lesions from dysplasia to carcinoma. Expressions of TLR4 and TLR9 were assessed using immunohistochemistry (IHC) on paraffin embedded tissue blocks of various grades of OED (28 cases), OSCC (27 cases) and NOM (10 cases). Expression of TLR4 was high in all grades of OED and OSCC. Expression of TLR9 was high in well differentiated squamous cell carcinoma and moderately differentiated squamous cell carcinomas, and moderate to low in poorly differentiated squamous cell carcinomas. Although expression was high in case of TLR4, it was not statistically significant. Expression of TLR9 was statistically significant. In OED, expression of TLR9 was less than that of TLR4. Our results indicated that the pattern of expression of TLR4 and TLR9 increased significantly from mild to severe dysplasia compared to controls. Expression of TLR4 and TLR9 reflects progression of OED to OSCC, which suggests that TLR may play a role in tumorigenesis and that it could be used as a target for OSCC prevention and therapy in the future.

Toll-like receptor-4 agonist inhibits motility and invasion of hepatoblastoma HepG2 cells in vitro

BACKGROUND

Expression of toll-like receptor-4 (TLR4) on tumor cells is known to mediate innate immune responses that influence tumor cell growth and migration. This study aimed to characterize TLR4 expression and elucidate its functional significance in human hepatoblastoma (HB) cells.

PROCEDURE

Immunohistochemistry (IHC) was used to determine TLR4 expression level and its distribution pattern in HB liver tissues. Transcripts of tumor necrosis factor (TNF)-α, interleukin (IL)-8, matrix metalloproteinase (MMP)-2, MMP-13, tissue inhibitor of metalloproteinases (TIMP)-1, and TIMP-2 in HB HepG2 cells with lipopolysacharide (LPS) treatment were measured by quantitative PCR. Soluble cytokines and peptides in conditioned media were measured by ELISA. MMP-2 activity was determined by using gelatin zymography. Cell motility and invasiveness was determined using wound healing migration and Matrigel invasion assays, respectively.

RESULTS

TLR4 IHC staining demonstrated that TLR4 overexpression in HB liver tissues dramatically vanished after chemotherapy. In vitro study using an HB cell line, HepG2, showed that TLR4 agonist, LPS, significantly decreased transcripts of IL-8 and TNF-α, but did not affect MMP-13 mRNA level. By contrast, LPS only down-regulated IL-8 production and MMP-2 gelatinolytic activity. The latter might be in part due to the increased levels of MMP-2/TIMP-2 complex in conditioned media, thus leading to the decreased motility and invasiveness of HepG2 cells.

CONCLUSIONS

HB cells overexpress TLR4, whereas TLR4 agonistic treatment inhibits migration and invasion of HB HepG2 cells. These findings suggest that TLR4 signaling pathway is a potential therapeutic target for control of HB tumor progression.

Dual character of Toll-like receptor signaling: pro-tumorigenic effects and anti-tumor functions

As a major class of pattern-recognition receptors, Toll-like receptors (TLRs) play a critical role in defense against invading pathogens. Increasing evidence demonstrates that, in addition to infection, TLRs are involved in other important pathological processes, such as tumorigenesis. Activation of TLRs results in opposing outcomes, pro-tumorigenic effects and anti-tumor functions. TLR signaling can inhibit apoptosis and promote chronic inflammation-induced tumorigenesis. TLR activation in tumor cells and immune cells can induce production of cytokines, increase tumor cell proliferation and apoptosis resistance, promote invasion and metastasis, and inhibit immune cell activity resulting in tumor immune escape. In contrast, the engagement of other TLRs directly induces growth inhibition and apoptosis of tumor cells and triggers activation of immune cells enhancing anti-tumor immune responses. Thus, the interpretation of the precise function of each TLR in tumors is very important for targeting TLRs and using TLR agonists in tumor therapy. We review the role of TLR signaling in tumors and discuss the factors that affect outcomes of TLR activation.

A TLR4-interacting peptide inhibits lipopolysaccharide-stimulated inflammatory responses, migration and invasion of colon cancer SW480 cells

Inflammation is a major risk factor for carcinogenesis in patients affected by chronic colitis, yet the molecular mechanisms underlying the progression from chronic inflammation to cancer are not completely understood. Activation of the Toll-like receptor 4 (TLR4)-NFκB signaling axis is associated with inflammation. Thus, we hypothesized that inhibition of TLR4-NFκB signaling might help in limiting inflammatory responses and inflammation-induced oncogenesis. In this work, we studied the effects of a TLR4-interacting surfactant protein A-derived (SPA4) peptide on lipopolysaccharide (LPS)-induced TLR4-NFκB signaling and cancer progression. We first characterized this peptide for its ability to bind the TLR4 ligand-LPS and for physico-chemical characteristics. Inflammation was induced by challenging the colon cancer SW480 cells with Escherichia coli LPS. Cells were then treated with varying amounts of the SPA4 peptide. Changes in the expression of TLR4, interleukin (IL)-1β and IL-6, in intracellular NFκB-related signal transducers (IKBα, p65, phosphorylated IKBα, phosphorylated p65, RelB, COX-2) as well as in the transcriptional activity of NFκB were studied by immunocytochemistry, immunoblotting and NFκB reporter assay, respectively. Simultaneously, the effects on LPS-induced cell migration and invasion were determined. We found that the SPA4 peptide does not bind to LPS. Rather, its binding to TLR4 inhibits the LPS-induced phosphorylation of p65, production of IL-1β and IL-6, activity of NFκB, migration and invasion of SW480 cells. In conclusion, our results suggest that the inhibition of TLR4-NFκB signaling by a TLR4-binding peptide may help for the treatment of chronic inflammation and prevention of inflammation-induced cancer in patients with colitis.

Pathogenic role of HIF-1α in prostate hyperplasia in the presence of chronic inflammation

Benign prostatic hyperplasia (BPH) commonly occurs in older men with chronic prostatitis. Although BPH is frequently accompanied by inflammation, it is unclear whether inflammation underlies prostate enlargement. Recently, we reported that hypoxia-inducible factor 1α (HIF-1α), which is known to be induced by proinflammatory cytokines, is involved in testosterone-induced prostate hyperplasia. Therefore, we hypothesized that cytokines secreted from infiltrated macrophages under inflammatory conditions stimulate prostate enlargement by up-regulating HIF-1α. In the present study, we injected lipopolysaccharide (LPS) into rat prostates to mimic prostatitis and evaluated prostate hyperplasia 14days later. Epithelial cells of LPS-treated prostates were found to be highly proliferative and HIF-1α levels in prostate tissues to be elevated. When prostate epithelial cells were incubated in conditioned medium from macrophages activated with LPS, they robustly expressed HIF-1α, and under these conditions IL-1β, IL-6, and TNF-α cytokines were found to mediate HIF-1α induction. In addition, HIF-1α was found to enhance the expression of Twist, which initiates epithelial-mesenchymal transition (EMT). Furthermore, profound EMT features were observed in LPS-treated rat prostates, and the natural HIF-1α inhibitors ascorbate and curcumin were found to attenuate EMT and prostate hyperplasia both in vivo and in vitro. Based on these results, we propose that HIF-1α mediates prostate enlargement under inflammatory conditions, and we suggest that HIF-1α be viewed as a promising target for blocking the transition from prostatitis to BPH.

Mucins and toll-like receptors: kith and kin in infection and cancer

Inflammation is underlying biological phenomenon common in infection and cancer. Mucins are glycoproteins which establish a physical barrier for undesirable entry of foreign materials through epithelial surfaces. A deregulated expression and an anomalous glycosylation pattern of mucins are known in large number of cancers. TLRs are class of receptors which recognize the molecular patterns of invading pathogens and activate complex inflammatory pathways to clear them. Aberrant expression of TLRs is observed in many cancers. A highly orchestrated action of mucins and TLRs is well evolved host defence mechanism; however, a link between the two in other non-infectious conditions has received less attention. Here we present an overview as to how mucins and TLRs give protection to the host and are deregulated during carcinogenesis. Further, we propose the possible mechanisms of cross-regulation between them in pathogenesis of cancer. As both mucins and TLRs are therapeutically important class of molecules, an understanding of the underlying molecular mechanisms connecting the two will open new avenues for the therapeutic targeting of cancer.

Exogenous or endogenous Toll-like receptor ligands: which is the MVP in tumorigenesis?

Toll-like receptors (TLRs) are a class of pattern recognition receptors sensing microbial components and triggering an immune response against pathogens. In addition to their role in anti-infection immunity, increasing evidence indicates that engagement of TLRs can promote cancer cell survival and proliferation, induce tumor immune evasion, and enhance tumor metastasis and chemoresistance. Recent studies have demonstrated that endogenous molecules or damage-associated molecular patterns released from damaged/necrotic tissues are capable of activating TLRs and that the endogenous ligands-mediated TLR signaling is implicated in the tumor development and affects the therapeutic efficacy of tumors. Since both exogenous and endogenous TLR ligands can initiate TLR signaling, which is the most valuable player in tumor development becomes an interesting question. Here, we summarize the effect of TLR signaling on the development and progression of tumors, and discuss the role of exogenous and endogenous TLR ligands in the tumorigenesis.

Genetic variation in the toll-like receptor 4 and prostate cancer incidence and mortality

BACKGROUND

Common genetic variants in the Toll-like receptor 4 (TLR4), which is involved in inflammation and immune response pathways, may be important for prostate cancer.

METHODS

In a large nested case-control study of prostate cancer in the Physicians' Health Study (1982-2004), 10 single nucleotide polymorphisms (SNPs) were selected and genotyped to capture common variation within the TLR4 gene as well as 5 kb up and downstream. Unconditional logistic regression was used to assess associations of these SNPs with total prostate cancer incidence, and with prostate cancers defined as advanced stage/lethal (T3/T4, M1/N1(T1-T4), lethal) or high Gleason grade (7 (4 + 3) or greater). Cox-proportional hazards regression was used to assess progression to metastases and death among prostate cancer cases.

RESULTS

The study included 1,267 controls and 1,286 incident prostate cancer cases, including 248 advanced stage/lethal and 306 high grade cases. During a median follow-up of 10.6 years, 183 men died of prostate cancer or developed distant metastases. No statistically significant associations between the TLR4 SNPs were found for total prostate cancer incidence, including SNPs for which an association was reported in other published studies. Additionally, there were no significant associations with TLR4 SNPS and the incidence of advanced stage/lethal, or high grade cancers; nor was there evidence among prostate cancer cases for associations of TLR4 SNPs with progression to prostate cancer specific mortality or bony metastases.

CONCLUSIONS

Results from this prospective nested case-control study suggest that genetic variation across TLR4 alone is not strongly associated with prostate cancer risk or mortality.

Anti-inflammatory effects of resveratrol occur via inhibition of lipopolysaccharide-induced NF-κB activation in Caco-2 and SW480 human colon cancer cells

Resveratrol, a polyphenol abundantly found in grapes and red wine, exhibits beneficial health effects due to its anti-inflammatory properties. In the present study, we evaluated the effect of resveratrol on inflammatory responses induced by lipopolysaccharide (LPS) treatment of human intestinal Caco-2 and SW480 cell lines. In the LPS-treated intestinal cells, resveratrol dose-dependently inhibited the expression of inducible NO synthase (iNOS) mRNA as well as protein expression, resulting in a decreased production of NO. In addition, Toll-like receptor-4 expression was significantly diminished in LPS-stimulated cells after resveratrol pre-treatment. To investigate the mechanisms by which resveratrol reduces NO production and iNOS expression, we examined the activation of inhibitor of κB (IκB) in LPS-stimulated intestinal cells. Results demonstrated that resveratrol inhibited the phosphorylation, as well as the degradation, of the IκB complex. Overall, these results show that resveratrol is able to reduce LPS-induced inflammatory responses by intestinal cells, interfering with the activation of NF-κB-dependent molecular mechanisms.

Toll-like receptor 4 activation in cancer progression and therapy

Cancer immunotherapy has been the focus of intense research since the late 19th century when Coley observed that bacterial components can contribute to cancer regression by eliciting an antitumor immune response. Successful activation and maturation of tumor-specific immune cells is now known to be mediated by bacterial endotoxin, which activates Toll-like receptor 4 (TLR4). TLR4 is expressed on a variety of immune as well as tumor cells, but its activation can have opposing effects. While TLR4 activation can promote antitumor immunity, it can also result in increased tumor growth and immunosuppression. Nevertheless, TLR4 engagement by endotoxin as well as by endogenous ligands represents notable contribution to the outcome of different cancer treatments, such as radiation or chemotherapy. Further research of the role and mechanisms of TLR4 activation in cancer may provide novel antitumor vaccine adjuvants as well as TLR4 inhibitors that could prevent inflammation-induced carcinogenesis.

Chemokine response induced by Chlamydia trachomatis in prostate derived CD45+ and CD45- cells

The role of innate cells and their receptors within the male genital tract remains poorly understood. Much less is known about the relative contribution of different genital tract cells such as epithelial/stromal cells and resident leucocytes. In this study, we examined innate immune responses to Chlamydia trachomatis by prostate epithelial/stromal cells and prostate resident leucocytes. Murine prostate primary cultures were performed and leucocyte and epithelial/stromal cells were sorted based on surface protein expression of CD45 by magnetism-activated cell sorting or fluorescence-activated cell sorting. Prostate derived CD45- and CD45+ cells were infected with C. trachomatis and chemokine secretion assayed by ELISA. Similar experiments were performed using prostate CD45+ and CD45- cells from myeloid differentiation factor 88 (Myd88(-/-)) mice or toll-like receptor (Tlr2(-/-)) and Tlr4(mutant) double-deficient mice. Moreover, a TLR-signalling pathway array was used to screen changes in different genes involved in TLR-signalling pathways by real-time PCR. Prostate derived CD45- and CD45+ cells responded to chlamydial infection with the production of different chemokines. Both populations expressed genes involved in TLR signalling and required to respond to pathogen-associated molecular patterns and to C. trachomatis infection. Both populations required the adaptor molecule MYD88 to elicit chemokine response against C. trachomatis. TLR2-TLR4 was essential for chemokine production by CD45+ prostate derived cells, but in their absence, CD45- cells still produced significant levels of chemokines. We demonstrate that C. trachomatis is differentially recognised by prostate derived CD45+ and CD45- cells and suggest that diverse strategies are taking place in the local microenvironment of the host in response to the infection.

Sequence variants of Toll-like receptor 4 (TLR4) and the risk of prostate cancer in Korean men

PURPOSE

Chronic inflammation has been considered a potential risk factor for prostate cancer. Toll-like receptors (TLRs) are important in the innate immune response to pathogens and in cross talk between innate immunity and adaptive immunity. In this study, sequence variants in the TLR4 gene were investigated to determine whether they were associated with prostate cancer risk in a Korean cohort.

METHODS

An association study between 11 single-nucleotide polymorphisms (SNPs) of the TLR4 gene and prostate cancer was performed in 463 Korean male subjects including 240 prostate cancer patients and 223 healthy controls. SNPs were genotyped using the TaqMan assay, and their association with the risk of prostate cancer was evaluated using logistic regression analysis.

RESULTS

The statistical analysis revealed that one SNP at the 3'UTR (rs11536889) showed significant association with the risk of prostate cancer (P (corr) = 0.005, OR = 1.81). One common haplotype (ht2) was also significantly associated with the risk of prostate cancer (P (corr) = 0.009, OR = 1.77). However, further analysis showed no association between any of the SNPs and prostate cancer prognostic factors such as the Gleason score or tumor stage.

CONCLUSIONS

The findings of this study suggest that polymorphisms of the TLR4 gene might be associated with the risk of prostate cancer in Korean men.

TPL2/COT/MAP3K8 (TPL2) activation promotes androgen depletion-independent (ADI) prostate cancer growth

BACKGROUND

Despite its initial positive response to hormone ablation therapy, prostate cancers invariably recur in more aggressive, treatment resistant forms. The lack of our understanding of underlying genetic alterations for the transition from androgen-dependent (AD) to ADI prostate cancer growth hampers our ability to develop target-driven therapeutic strategies for the efficient treatment of ADI prostate cancer.

METHODOLOGY/PRINCIPAL FINDINGS

By screening a library of activated human kinases, we have identified TPL2, encoding a serine/threonine kinase, as driving ADI prostate cancer growth. TPL2 activation by over-expressing either wild-type or a constitutively activated form of TPL2 induced ADI growth, whereas the suppression of TPL2 expression and its kinase activity in ADI prostate cancer cells inhibited cell proliferation under androgen-depleted conditions. Most importantly, TPL2 is upregulated in ADI prostate cancers of both the Pten deletion mouse model and the clinical prostate cancer specimens.

CONCLUSIONS/SIGNIFICANCE

Together these data suggest that TPL2 kinase plays a critical role in the promotion of ADI prostate cancer progression. Furthermore, the suppression of TPL2 diminishes ADI prostate cancer growth and a high frequency of TPL2 overexpression in human ADI prostate cancer samples validates TPL2 as a target for the treatment of this deadly disease.

Activation of NF-{kappa}B by TMPRSS2/ERG Fusion Isoforms through Toll-Like Receptor-4

The TMPRSS2/ERG (T/E) fusion gene is present and thought to be an oncogenic driver of approximately half of all prostate cancers. Fusion of the androgen-regulated TMPRSS2 promoter to the ERG oncogene results in constitutive high level expression of ERG which promotes prostate cancer invasion and proliferation. Here, we report the characterization of multiple alternatively spliced T/E fusion gene isoforms which have differential effects on invasion and proliferation. We found that T/E fusion gene isoforms differentially increase NF-κB-mediated transcription, which may explain in part the differences in biological activities of the T/E fusion isoforms. This increased activity is due to phosphorylation of NF-κB p65 on Ser536. Tissue microarray immunochemistry revealed that p65 phospho-Ser536 is present in the majority of prostate cancers where it is associated with ERG protein expression. The T/E fusion gene isoforms differentially increase expression of a number of NF-κB associated genes including PAR1, CCL2, FOS, TLR3, and TLR4 (Toll-like receptor). TLR4 activation is known to promote p65 Ser536 phosphorylation and knockdown of TLR4 with shRNA decreases Ser536 phosphorylation in T/E fusion gene expressing cells. TLR4 can be activated by proteins in the tumor microenvironment and lipopolysacharide from Gram (-) bacteria. Our findings suggest that bacterial infection of the prostate and/or endogenous microenvironment proteins may promote progression of high-grade prostatic intraepithelial neoplasia and/or prostate cancers that express the T/E fusion gene, where the NF-κB pathway might be targeted as a rational therapeutic approach.

Innate immunity in the male genital tract: Chlamydia trachomatis induces keratinocyte-derived chemokine production in prostate, seminal vesicle and epididymis/vas deferens primary cultures

Chlamydia trachomatis is an intracellular pathogen that infects mucosal epithelial cells, causing persistent infections. Although chronic inflammation is a hallmark of chlamydial disease, the proinflammatory mechanisms involved are poorly understood. Little is known about how innate immunity in the male genital tract (MGT) responds to C. trachomatis. Toll-like receptors (TLRs) are a family of receptors of the innate immunity that recognize different pathogen-associated molecular patterns (PAMPs) present in bacteria, viruses, yeasts and parasites. The study of TLR expression in the MGT has been poorly investigated. The aim of this work was to investigate the keratinocyte-derived chemokine (KC) response of MGT primary cultures from C57BL/6 mice to C. trachomatis and different PAMPs. KC production by prostate, seminal vesicle and epididymis/vas deferens cell cultures was determined by ELISA in culture supernatants. TLR2, 3, 4 and 9 agonists induced the production of KC by all MGT primary cultures assayed. In addition, we analysed the host response against C. trachomatis and Chlamydia muridarum. Chlamydial LPS (cLPS) as well as C. trachomatis and C. muridarum infection induced KC secretion by all MGT cell cultures analysed. Differences in KC levels were observed between cultures, suggesting specific sensitivity against pathogens among MGT tissues. Chemokine secretion was observed after stimulation of seminal vesicle cells with TLR agonists, cLPS and C. trachomatis. To our knowledge, this is the first report showing KC production by seminal vesicle cells after stimulation with TLR ligands, C. trachomatis or C. muridarum antigens. These results indicate that different receptors of the innate immunity are present in the MGT. Understanding specific immune responses, both innate and adaptive, against chlamydial infections, mounted in each tissue of the MGT, will be crucial to design new therapeutic approaches where innate and/or adaptive immunity would be targeted.

The application of Toll like receptors for cancer therapy

Toll-like receptor (TLR) proteins play key roles in immune responses against infection. Using TLR proteins, host can recognize the conserved molecular structures found in pathogens called pathogen-associated molecular patterns (PAMPs). At the same time, some TLRs are able to detect specific host molecules, such as high-mobility group box protein 1 (HMGB1) and heat shock proteins (hsp), and lead to inflammatory responses. Thus, it has been suggested that TLRs are involved in the development of many pathogenic conditions. Recent advances in TLR-related research not only provide us with scientific information, but also show the therapeutic potential against diseases, such as autoimmune disease and cancer. In this mini review, we demonstrate how TLRs pathways could be involved in cancer development and their therapeutic application, and discuss recent patentable subjects, in particular, that are targeting this unique pathway.

Non-Steroidal Anti-Inflammatory Drugs, Variation in Inflammatory Genes, and Aggressive Prostate Cancer

Increasing evidence suggests that prostatic inflammation plays a key role in the development of prostate cancer. It remains controversial whether non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of prostate cancer. Here, we investigate how a previously reported inverse association between NSAID use and the risk of aggressive prostate cancer is modulated by variants in several inflammatory genes. We found that NSAIDs may have differential effects on prostate cancer development, depending on one’s genetic makeup. Further study of these inflammatory pathways may clarify the mechanisms through which NSAIDs impact prostate cancer risk.

Acute inflammation promotes early cellular stimulation of the epithelial and stromal compartments of the rat prostate

BACKGROUND

It has been proposed that prostatic inflammation plays a pivotal role in the pathophysiology of benign hyperplasia and prostate cancer. However, little information is available about the prostatic reaction to bacterial compounds in vivo. Our aim was therefore to evaluate the early effects of bacterial infection on rat ventral prostate compartments.

METHODS

Using a rat model of acute bacterial prostatitis by Escherichia coli, we analyzed the histological and ultrastructural changes in the prostate at 24, 48, and 72 hr postinfection. Prostatic tissues were immunostained for prostatic binding protein (PBP), ACTA2, ErbB1, and ErbB2 receptors, TUNEL, and markers of cell proliferation. Dot and Western blots for PBP, ACTA2, ErbB1, ErbB2, and TGFbeta1 were also performed.

RESULTS

The prostatic epithelium became hypertrophied, with increases in PBP and ErbB1 expression at 24 hr postinfection. Moreover, inflammation induced the expression of ErbB2, a receptor strongly involved in carcinogenesis. These alterations were more pronounced at 48 hr, but the epithelium also showed apoptosis and finally atrophy at 72 hr postinfection, with a decrease in PBP and ErbB receptors. Interestingly, the epithelial cells exhibited a high level of proliferation in response to the bacteria. The stromal reaction to acute inflammation was initially characterized by smooth muscle hypertrophy. Afterwards, muscle cells acquired a secretory phenotype, with a reduction in ACTA2 at 72 hr postinfection.

CONCLUSIONS

Prostatic inflammation, even at the early stages, promotes atrophic and proliferative changes, and the upregulation of ErbB receptors together with dedifferentiation of smooth muscle cells. These data suggest that repetitive reinfections could lead to uncontrolled growth in the prostate gland.

Expression of toll-like receptor-9 is increased in poorly differentiated prostate tumors

BACKGROUND

Toll-like receptor-9 (TLR9) is a cellular receptor for bacterial and vertebrate DNA. In addition to cells of the immune system, it is also expressed in various human cancer cell lines, including prostate cancer. We demonstrated previously that synthetic TLR9 ligands induce matrix metalloproteinase-13-mediated invasion in TLR9-expressing prostate cancer cells in vitro. Other studies have suggested possible sex steroid regulation of the function of the various TLRs. The role of TLR9 in the pathophysiology of prostate or any cancer is, however, unknown.

METHODS

Expression of TLR9, androgen receptor (AR), or the estrogen receptors alpha (ERalpha) and beta (ERbeta) were studied with immunohistochemistry in prostate cancer (n = 62) and benign prostatic hyperplasia (n = 45) specimens. TLR9 staining scores were compared with tumor stage, Gleason score, prostate-specific antigen (PSA) concentrations before tissue sampling and with the staining scores of AR, ERalpha, and ERbeta.

RESULTS

TLR9 expression was statistically significantly increased in prostate cancer epithelium and stroma, as compared with the same cellular compartments in benign hyperplasia. Significantly increased (P = 0.04) TLR9 expression was detected in cancers with high Gleason score (>7, n = 23), as compared with lower Gleason scores (< or =7, n = 39). No statistically significant associations were detected between TLR9 expression scores and PSA concentrations or tumor staging. Prostate adenocarcinoma cells were all positive for TLR9, AR, and ERbeta but negative for ERalpha expression. In cancer stroma cells, increased TLR9 expression was associated with increased ERalpha expression.

CONCLUSIONS

Expression of TLR9 is increased in prostate cancer specimens, especially in the most poorly differentiated forms.