COX-derived prostanoid pathways in gastrointestinal cancer development and progression : novel targets for prevention and intervention

Arachidonic acid metabolism through cyclooxygenase (COX) pathways leads to the generation of biologically active eicosanoids. Eicosanoid expression levels vary during development and progression of gastrointestinal (GI) malignancies. COX-2 is the major COX-isoform responsible for G.I. cancer development/progression. COX-2 expression increases during progression from a normal to cancerous state. Evidence from observational studies has demonstrated that chronic NSAID use reduces the risk of cancer development, while both incidence and risk of death due to G.I. cancers were significantly reduced by daily aspirin intake. A number of randomized controlled trials (APC trial, Prevention of Sporadic Adenomatous Polyps trial, APPROVe trial) have also shown a significant protective effect in patients receiving selective COX-2 inhibitors. However, chronic use of selective COX-2 inhibitors at high doses was associated with increased cardiovascular risk, while NSAIDs have also been associated with increased risk. More recently, downstream effectors of COX-signaling have been investigated in cancer development/progression. PGE 2, which binds to both EP and PPAR receptors, is the major prostanoid implicated in the carcinogenesis of G.I. cancers. The role of TXA 2 in G.I. cancers has also been examined, although further studies are required to uncover its role in carcinogenesis. Other prostanoids investigated include PGD 2 and its metabolite 15d-PGJ2, PGF 1α and PGI 2. Targeting these prostanoids in G.I. cancers has the promise of avoiding cardiovascular toxicity associated with chronic selective COX-2 inhibition, while maintaining anti-tumor reactivity.A progressive sequence from normal to pre-malignant to a malignant state has been identified in G.I. cancers. In this review, we will discuss the role of the COX-derived prostanoids in G.I. cancer development and progression. Targeting these downstream prostanoids for chemoprevention and/or treatment of G.I. cancers will also be discussed. Finally, we will highlight the latest pre-clinical technologies as well as avenues for future investigation in this highly topical research field. © 2011 Elsevier B.V.

Quality of life and survival in patients treated with radical chemoradiation alone for oesophageal cancer

Aims: To report cancer-specific and health-related quality-of-life outcomes in patients undergoing radical chemoradiation (CRT) alone for oesophageal cancer. Materials and methods: Between 1998 and 2005, 56 patients with oesophageal cancer received definitive radical CRT, due to local disease extent, poor general health, or patient choice. Data from European Organization for Research and Treatment of Cancer quality-of-life questionnaires QLQ-30 and QLQ-OES24 were collected prospectively. Questionnaires were completed at diagnosis, and at 3, 6 and 12 months after CRT where applicable. Results: The median follow-up was 18 months. The median overall survival was 14 months, with a 51, 26 and 13% 1-, 3- and 5-year survival, respectively. At 12 months after treatment there was a significant improvement compared with before treatment with respect to dysphagia and pain. Global health scores were not significantly affected. Conclusions: Considering the relatively short long-term survival for this cohort of patients, maximising the quality of those final months should be very carefully borne in mind from the outset. The health-related quality-of-life data reported herein helps to establish benchmarks for larger evaluation within randomised clinical trials. © 2007 The Royal College of Radiologists.

Crizotinib versus chemotherapy in advanced ALK-positive lung cancer

BACKGROUND: In single-group studies, chromosomal rearrangements of the anaplastic lymphoma kinase gene (ALK ) have been associated with marked clinical responses to crizotinib, an oral tyrosine kinase inhibitor targeting ALK. Whether crizotinib is superior to standard chemotherapy with respect to efficacy is unknown. METHODS: We conducted a phase 3, open-label trial comparing crizotinib with chemotherapy in 347 patients with locally advanced or metastatic ALK-positive lung cancer who had received one prior platinum-based regimen. Patients were randomly assigned to receive oral treatment with crizotinib (250 mg) twice daily or intravenous chemotherapy with either pemetrexed (500 mg per square meter of body-surface area) or docetaxel (75 mg per square meter) every 3 weeks. Patients in the chemotherapy group who had disease progression were permitted to cross over to crizotinib as part of a separate study. The primary end point was progression-free survival. RESULTS: The median progression-free survival was 7.7 months in the crizotinib group and 3.0 months in the chemotherapy group (hazard ratio for progression or death with crizotinib, 0.49; 95% confidence interval [CI], 0.37 to 0.64; P<0.001). The response rates were 65% (95% CI, 58 to 72) with crizotinib, as compared with 20% (95% CI, 14 to 26) with chemotherapy (P<0.001). An interim analysis of overall survival showed no significant improvement with crizotinib as compared with chemotherapy (hazard ratio for death in the crizotinib group, 1.02; 95% CI, 0.68 to 1.54; P=0.54). Common adverse events associated with crizotinib were visual disorder, gastrointestinal side effects, and elevated liver aminotransferase levels, whereas common adverse events with chemotherapy were fatigue, alopecia, and dyspnea. Patients reported greater reductions in symptoms of lung cancer and greater improvement in global quality of life with crizotinib than with chemotherapy. CONCLUSIONS: Crizotinib is superior to standard chemotherapy in patients with previously treated, advanced non-small-cell lung cancer with ALK rearrangement. (Funded by Pfizer; ClinicalTrials.gov number, NCT00932893.) Copyright © 2013 Massachusetts Medical Society.

Phase II trial of Oxaliplatin and 5-Fluorouracil/Leucovorin combination in epithelial ovarian carcinoma relapsing within 2 years of platinum-based therapy

Objective To evaluate the efficacy and toxicity of Oxaliplatin and 5-Fluorouracil (5-FU)/Leucovorin (LV) combination in ovarian cancer relapsing within 2 years of prior platinum-based chemotherapy in a phase II trial. Methods Eligible patients had at least one prior platinum-based chemotherapy regimen, elevated CA-125 ≥ 60 IU/l, radiological evidence of disease progression and adequate hepatic, renal and bone marrow function. Patients with raised CA-125 levels alone as marker of disease relapse were not eligible. Oxaliplatin (85 mg/m 2) was given on day 1, and 5-Fluorouracil (370 mg/m 2) and Leucovorin (30 mg) was given on days 1 and 8 of a 14-day cycle. Results Twenty-seven patients were enrolled. The median age was 57 years (range 42-74 years). The median platinum-free interval (PFI) was 5 months (range 0-17 months) with only 30% of patients being platinum sensitive (PFI > 6 months). Six patients (22%) had two prior regimens of chemotherapy. A total of 191 cycles were administered (median 7; range 2-12). All patients were evaluable for toxicity. The following grade 3/4 toxicities were noted: anemia 4%; neutropenia 15%; thrombocytopenia 11%; neurotoxicity 8%; lethargy 4%; diarrhea 4%; hypokalemia 11%; hypomagnesemia 11%. Among 27 enrolled patients, 20 patients were evaluable for response by WHO criteria and 25 patients were evaluable by Rustin's CA-125 criteria. The overall response rate (RR) by WHO criteria was 30% (95% CI: 15- 52) [three complete responses (CRs) and three partial responses (PRs)]. The CA-125 response rate was 56% (95% CI: 37-73). Significantly, a 25% (95% CI: 9-53) radiological and a 50% (95% CI: 28-72) CA-125 response rate were noted in platinum resistant patients (PFI < 6 months). The median response duration was 4 months (range 3-12) and the median overall survival was 10 months. Conclusion Oxaliplatin and 5-Fluorouracil/ Leucovorin combination has a good safety profile and is active in platinum-pretreated advanced epithelial ovarian cancer. © 2004 Elsevier Inc. All rights reserved.

Chemotherapy for upper gastrointestinal tumours

The aim of this review is to identify current chemotherapy treatment for tumours of the oesophagus, stomach, pancreas, and liver. The role of both neoadjuvant, adjuvant, and palliative chemotherapy regimens will be discussed. This review will be of interest to oncologists in clarifying current issues regarding chemotherapy, and to physicians in other medical specialties, to increase their general understanding of benefits and drawbacks of chemotherapy in this patient group.

Risks for HIV infection among male street laborers in urban Vietnam

Risks for HIV infection remain unknown in male street laborers. This research investigates patterns of self-reported risk behaviors among these men in urban Vietnam. In a cross-sectional survey using a social mapping technique, 450 men, mostly low-skilled and unregistered migrant laborers across 13 districts in Hanoi were approached for interviews. The study revealed that male street laborers were at high risk of acquiring and transmitting HIV. One in every 12 men reported homosexual or bisexual behavior. These men on average had three sexual partners within the preceding year, and condom use was inconsistent. Close to 95 % of the men had reported sexual encounters with regular partners. One-third with commercial sex workers (CSW) and 24.2 % with casual partners, but just under one-third had ever used condoms with regular partners and CSWs and very few (17.6 %) with casual partners at their last sexual encounter. 17.11 % used illicit drugs sometimes, with 66.7 % of them frequently sharing injecting equipment with peers. These men had limited HIV knowledge; 51.4 % incorrectly believed that, once you trust your partner, you no longer need to use condoms and 42.4 % believed that you can tell by looking at someone if they have HIV. Access to HIV prevention was also limited; only 19.8 % of men had been tested for HIV during the previous 12 months, almost 10 % of whom neither returned for the result nor knew their HIV status. The study provides interesting directions for future research and suggests ways to effectively design prevention strategies for these men.

Oral immunization with a novel lipid-based adjuvant protects against genital Chlamydia infection

Oral immunization is attractive as a delivery route because it is needle-free and useful for rapid mass vaccination programs to target pandemics or bioterrorism. This potential has not been realized for human vaccination, due to the requirement of large antigen doses and toxic (to humans) adjuvants to overcome the induction of oral tolerance and potential degradation of antigens in the stomach. To date, only oral vaccines based on live attenuated organisms have been approved for human use. In this study we describe the use of a lipid-based delivery system/adjuvant, Lipid C, for oral immunization to protect mice against genital tract chlamydial infection. Lipid C is formulated from food-grade purified and fractionated triglycerides. Bacterial shedding following vaginal challenge with Chlamydia muridarum was reduced by 50% in female mice orally immunized with the chlamydial major outer membrane protein (MOMP) formulated in Lipid C, protection equivalent to that seen in animals immunized with MOMP admixed with both cholera toxin (CT) and CpG oligodeoxynucleotides (CpG-ODN). Protection was further enhanced when MOMP, CT and CpG were all combined in the Lipid C matrix. Protection correlated with production of gamma interferon (IFN) by splenic T cells, a serum MOMP-specific IgG response and low but detectable levels of MOMP-specific IgA in vaginal lavage.

Transcutaneous immunization with combined cholera toxin and CpG adjuvant protects against Chlamydia muridarum genital tract infection

Chlamydia trachomatis is a pathogen of the genital tract and ocular epithelium. Infection is established by the binding of the metabolically inert elementary body (EB) to epithelial cells. These are taken up by endocytosis into a membrane-bound vesicle termed an inclusion. The inclusion avoids fusion with host lysosomes, and the EBs differentiate into the metabolically active reticulate body (RB), which replicates by binary fission within the protected environment of the inclusion. During the extracellular EB stage of the C. trachomatis life cycle, antibody present in genital tract or ocular secretions can inhibit infection both in vivo and in tissue culture. The RB, residing within the intracellular inclusion, is not accessible to antibody, and resolution of infection at this stage requires a cell-mediated immune response mediated by gamma interferon-secreting Th1 cells. Thus, an ideal vaccine to protect against C. trachomatis genital tract infection should induce both antibody (immunoglobulin A [IgA] and IgG) responses in mucosal secretions to prevent infection by chlamydial EB and a strong Th1 response to limit ascending infection to the uterus and fallopian tubes. In the present study we show that transcutaneous immunization with major outer membrane protein (MOMP) in combination with both cholera toxin and CpG oligodeoxynucleotides elicits MOMP-specific IgG and IgA in vaginal and uterine lavage fluid, MOMP-specific IgG in serum, and gamma interferon-secreting T cells in reproductive tract-draining caudal and lumbar lymph nodes. This immunization protocol resulted in enhanced clearance of C. muridarum (C. trachomatis, mouse pneumonitis strain) following intravaginal challenge of BALB/c mice.

The IL-6 response to Chlamydia from primary reproductive epithelial cells is highly variable and may be involved in differential susceptibility to the immunopathological consequences of chlamydial infection

Background Chlamydia trachomatis infection results in reproductive damage in some women. The process and factors involved in this immunopathology are not well understood. This study aimed to investigate the role of primary human cellular responses to chlamydial stress response proteases and chlamydial infection to further identify the immune processes involved in serious disease sequelae. Results Laboratory cell cultures and primary human reproductive epithelial cultures produced IL-6 in response to chlamydial stress response proteases (CtHtrA and CtTsp), UV inactivated Chlamydia, and live Chlamydia. The magnitude of the IL-6 response varied considerably (up to 1000 pg ml-1) across different primary human reproductive cultures. Thus different levels of IL-6 production by reproductive epithelia may be a determinant in disease outcome. Interestingly, co-culture models with either THP-1 cells or autologous primary human PBMC generally resulted in increased levels of IL-6, except in the case of live Chlamydia where the level of IL-6 was decreased compared to the epithelial cell culture only, suggesting this pathway may be able to be modulated by live Chlamydia. PBMC responses to the stress response proteases (CtTsp and CtHtrA) did not significantly vary for the different participant cohorts. Therefore, these proteases may possess conserved innate PAMPs. MAP kinases appeared to be involved in this IL-6 induction from human cells. Finally, we also demonstrated that IL-6 was induced by these proteins and Chlamydia from mouse primary reproductive cell cultures (BALB/C mice) and mouse laboratory cell models. Conclusions We have demonstrated that IL-6 may be a key factor for the chlamydial disease outcome in humans, given that primary human reproductive epithelial cell culture showed considerable variation in IL-6 response to Chlamydia or chlamydial proteins, and that the presence of live Chlamydia (but not UV killed) during co-culture resulted in a reduced IL-6 response suggesting this response may be moderated by the presence of the organism.

Mycobacterium abscessus isolated from municipal water : a potential source of human infection

Background Mycobacterium abscessus is a rapidly growing mycobacterium responsible for progressive pulmonary disease, soft tissue and wound infections. The incidence of disease due to M. abscessus has been increasing in Queensland. In a study of Brisbane drinking water, M. abscessus was isolated from ten different locations. The aim of this study was to compare genotypically the M. abscessus isolates obtained from water to those obtained from human clinical specimens. Methods Between 2007 and 2009, eleven isolates confirmed as M. abscessus were recovered from potable water, one strain was isolated from a rainwater tank and another from a swimming pool and two from domestic taps. Seventy-four clinical isolates referred during the same time period were available for comparison using rep-PCR strain typing (Diversilab). Results The drinking water isolates formed two clusters with ≥97% genetic similarity (Water patterns 1 and 2). The tankwater isolate (WP4), one municipal water isolate (WP3) and the pool isolate (WP5) were distinctly different. Patient isolates formed clusters with all of the water isolates except for WP3. Further patient isolates were unrelated to the water isolates. Conclusion The high degree of similarity between strains of M. abscessus from potable water and strains causing infection in humans from the same geographical area, strengthens the possibility that drinking water may be the source of infection in these patients.

Immunity against a Chlamydia infection and disease may be determined by a balance of IL-17 signaling

Most vaccines developed against Chlamydia using animal models provide partial protection against a genital tract infection. However, protection against the oviduct pathology associated with infertility is highly variable and often has no defining immunological correlate. When comparing two adjuvants (CTA1-DD and a combination of Cholera toxin plus CpG- oligodeoxynucleotide–CT/CpG) combined with the chlamydial major outer membrane protein (MOMP) antigen and delivered via the intranasal (IN), sublingual (SL) or transcutaneous (TC) routes, we identified two vaccine groups with contrasting outcomes following infection. SL immunization with MOMP/CTA1-DD induced a 70% reduction in the incidence of oviduct pathology, without significantly altering the course of infection. Conversely, IN immunization with MOMP/CT/CpG prevented an ascending infection, but not the oviduct pathology. This anomaly presented a unique opportunity to study the mechanisms by which vaccines can prevent oviduct pathology, other than by controlling the infection. The IL-17 signaling in the oviducts was found to associate with both the enhancement of immunity to infection and the development of oviduct pathology. This conflicting role of IL-17 may provide some explanation for the discordance in protection between infection and disease and suggests that controlling immunopathology, as opposed to the rapid eradication of the infection, may be essential for an effective human chlamydial vaccine that prevents infertility.

The mouse model of Chlamydia genital tract infection: a review of infection, disease, immunity and vaccine development

Chlamydia trachomatis is the most common sexually transmitted bacterial infection worldwide. The impact of this pathogen on human reproduction has intensified research efforts to better understand chlamydial infection and pathogenesis. Whilst there are animal models available that mimic the many aspects of human chlamydial infection, the mouse is regarded as the most practical and widely used of the models. Studies in mice have greatly contributed to our understanding of the host-pathogen interaction and provided an excellent medium for evaluating vaccines. Here we explore the advantages and disadvantages of all animal models of chlamydial genital tract infection, with a focus on the murine model and what we have learnt from it so far.

Preliminary characterisation of tumor necrosis factor alpha and interleukin-10 responses to chlamydia pecorum infection in the koala (Phascolarctos cinereus)

Debilitating infectious diseases caused by Chlamydia are major contributors to the decline of Australia's iconic native marsupial species, the koala (Phascolarctos cinereus). An understanding of koala chlamydial disease pathogenesis and the development of effective strategies to control infections continue to be hindered by an almost complete lack of species-specific immunological reagents. The cell-mediated immune response has been shown to play an influential role in the response to chlamydial infection in other hosts. The objective of this study, hence, was to provide preliminary data on the role of two key cytokines, pro-inflammatory tumour necrosis factor alpha (TNFα) and anti-inflammatory interleukin 10 (IL10), in the koala Chlamydia pecorum response. Utilising sequence homology between the cytokine sequences obtained from several recently sequenced marsupial genomes, this report describes the first mRNA sequences of any koala cytokine and the development of koala specific TNFα and IL10 real-time PCR assays to measure the expression of these genes from koala samples. In preliminary studies comparing wild koalas with overt chlamydial disease, previous evidence of C. pecorum infection or no signs of C. pecorum infection, we revealed strong but variable expression of TNFα and IL10 in wild koalas with current signs of chlamydiosis. The description of these assays and the preliminary data on the cell-mediated immune response of koalas to chlamydial infection paves the way for future studies characterising the koala immune response to a range of its pathogens while providing reagents to assist with measuring the efficacy of ongoing attempts to develop a koala chlamydial vaccine.

Immunization with a MOMP-based vaccine protects mice against a Pulmonary Chlamydia challenge and identifies a disconnection between infection and pathology

Chlamydia pneumoniae is responsible for up to 20% of community acquired pneumonia and can exacerbate chronic inflammatory diseases. As the majority of infections are either mild or asymptomatic, a vaccine is recognized to have the greatest potential to reduce infection and disease prevalence. Using the C. muridarum mouse model of infection, we immunized animals via the intranasal (IN), sublingual (SL) or transcutaneous (TC) routes, with recombinant chlamydial major outer membrane protein (MOMP) combined with adjuvants CTA1-DD or a combination of cholera toxin/CpG-oligodeoxynucleotide (CT/CpG). Vaccinated animals were challenged IN with C. muridarum and protection against infection and pathology was assessed. SL and TC immunization with MOMP and CT/CpG was the most protective, significantly reducing chlamydial burden in the lungs and preventing weight loss, which was similar to the protection induced by a previous live infection. Unlike a previous infection however, these vaccinations also provided almost complete protection against fibrotic scarring in the lungs. Protection against infection was associated with antigen-specific production of IFNγ, TNFα and IL-17 by splenocytes, however, protection against both infection and pathology required the induction of a similar pro-inflammatory response in the respiratory tract draining lymph nodes. Interestingly, we also identified two contrasting vaccinations capable of preventing infection or pathology individually. Animals IN immunized with MOMP and either adjuvant were protected from infection, but not the pathology. Conversely, animals TC immunized with MOMP and CTA1-DD were protected from pathology, even though the chlamydial burden in this group was equivalent to the unimmunized controls. This suggests that the development of pathology following an IN infection of vaccinated animals was independent of bacterial load and may have been driven instead by the adaptive immune response generated following immunization. This identifies a disconnection between the control of infection and the development of pathology, which may influence the design of future vaccines.