Programmed death ligand-1 over-expression correlates with malignancy and contributes to immune regulation in ovarian cancer

The programmed death-1 (PD-1) pathway is important in the maintenance of peripheral tolerance and homeostasis through suppression of T cell receptor signaling. As such, it is employed by many tumors as a means of immune escape. We have investigated the role of this pathway in human ovarian cancer (OC) to assess its potential role as a diagnostic and/or prognostic marker and therapeutic target, following recent clinical trial success of antibody therapy directed at this pathway. We show programmed death ligand-1 (PD-L1) expression on monocytes in the ascites and blood of patients with malignant OC is strikingly higher than those with benign/borderline disease, with no overlap in the values between these groups. We characterize the regulation of this molecule and show a role of IL-10 present in ascitic fluid. Flow cytometric analysis of T cells present in the ascites and blood showed a correlation of PD-1 expression with malignant tumors versus benign/borderline, in a similar manner to PD-L1 expression on monocytes. Finally, we demonstrate functional links between PD-L1 expression on monocytes and OC tumor cells with suppression of T cell responses. Overall, we present data based on samples obtained from women with ovarian cancer, suggesting the PD-1 pathway may be used as a reliable diagnostic marker in OC, as well as a viable target for use with PD-1/PD-L1-directed antibody immunotherapy.     

Molecular identification of blood meal sources of ticks (Acari,Ixodidae) using cytochrome b gene as a genetic marker

Blood meal analysis (BMA) from ticks allows for the identification of natural hosts of ticks (Acari: Ixodidae). The aim of this study is to identify the blood meal sources of field collected on-host ticks using PCR analysis. DNA of four genera of ticks was isolated and their cytochrome b (Cyt b) gene was amplified to identify host blood meals. A phylogenetic tree was constructed based on data of Cyt b sequences using Neighbor Joining (NJ) and Maximum Parsimony (MP) analysis using MEGA 5.05 for the clustering of hosts of tick species. Twenty out of 27 samples showed maximum similarity (99%) with GenBank sequences through a Basic Local Alignment Search Tool (BLAST) while 7 samples only showed a similarity range of between 91–98%. The phylogenetic trees showed that the blood meal samples were derived from small rodents (Leopoldamys sabanus, Rattus tiomanicus and Sundamys muelleri), shrews (Tupaia glis) and mammals (Tapirus indicus and Prionailurus bengalensis), supported by 82–88% bootstrap values. In this study, Cyt b gene as a molecular target produced reliable results and was very significant for the effective identification of ticks’ blood meal. The assay can be used as a tool for identifying unknown blood meals of field collected on-host ticks.     

The stingless bee honey protects against hydrogen peroxide-induced oxidative damage and lipopolysaccharide-induced inflammation in vitro

Oxidative stress, DNA damage, and unresolved inflammation are the predisposing factors of many chronic and degenerative diseases, including cancer. Stingless bee honey (SBH) is recognized to have high medicinal value by traditional medicine practitioners and has been used to treat various illnesses traditionally. This study aimed to determine the antioxidant, anti-inflammatory, and genoprotective effects of SBH by using in vitro cell culture models. The sugar content, total phenolic content, radical scavenging activity, and ferric reducing antioxidant power (FRAP) of SBH were determined in this study. Then, the protective effect of SBH against hydrogen peroxide (H₂O₂)-induced cell death and DNA damage was studied by using WIL2-NS human lymphoblastoid cell line, while the lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages cell line was used to study the anti-inflammatory effects of SBH. Results from this present study showed that the major sugar contents of SBH were fructose (19.39 + 0.01%) and glucose (14.03 ± 0.03%). Besides, the total phenolic content, the radical scavenging activity, and the FRAP value of SBH were 15.38 ± 0.02 mg GAE/100 g of honey, 34.04 ± 0.21%, and 206.77 + 1.76 μM AAE/100 g honey respectively. Pretreatment with SBH protected WIL2-NS cells from H₂O₂-induced cell death and DNA damage (p < 0.001). Moreover, SBH was also able to attenuate the production of nitric oxide by inhibiting the expression of inducible nitric oxide synthase in LPS-induced RAW 264.7 cells (p < 0.001). In conclusion, SBH is rich in total phenolic content and possesses strong antioxidant, anti-inflammatory, and genoprotective properties. Our current findings suggest that SBH might be useful in the prevention and treatment of many diseases caused by oxidative stress and inflammation assuming the observed effects are also achievable in vivo.