Efficient growth inhibition of EGFR over-expressing tumor cells by an anti-EGFR nanobody

Epidermal growth factor receptor (EGFR) is deemed to be one of the main molecular targets for diagnosis and treatment of cancer. It has been identified that EGFR involves in pathogenesis of some forms of human cancers. Monoclonal antibodies targeting EGFR could control the tumor cell growth, proliferation, and apoptosis by suppressing the signal transduction pathways. Nanobodies can be regarded as the smallest intact antigen binding fragments, derived from heavy chain-only antibodies existing in camelids. Here, we describe the identification of an EGFR-specific nanobody, referred to as OA-cb6, obtained from immunized camel with a cell line expressing high levels of EGFR. Utilizing flow cytometry (FACS) and blotting methods, we demonstrated that OA-cb6 nanobody binds specifically to EGFR expressing on the surface of A431 cells. In addition, OA-cb6 nanobody potently causes the inhibition of EGFR over expression, cell growth and proliferation. The antibody fragments can probably be regarded as worthwhile binding block for further rational design of anti-cancer therapy.     

The lipogenic enzymes DGAT1, FAS, and LPL in adipose tissue: effects of obesity, insulin resistance, and TZD treatment

Acyl-coenzyme A:diacylglycerol transferase (DGAT), fatty acid synthetase (FAS), and LPL are three enzymes important in adipose tissue triglyceride accumulation. To study the relationship of DGAT1, FAS, and LPL with insulin, we examined adipose mRNA expression of these genes in subjects with a wide range of insulin sensitivity (SI). DGAT1 and FAS (but not LPL) expression were strongly correlated with SI. In addition, the expression of DGAT1 and FAS (but not LPL) were higher in normal glucose-tolerant subjects compared with subjects with impaired glucose tolerance (IGT) (P < 0.005). To study the effects of insulin sensitizers, subjects with IGT were treated with pioglitazone or metformin for 10 weeks, and lipogenic enzymes were measured in adipose tissue. After pioglitazone treatment, DGAT1 expression was increased by 33 +/- 10% (P < 0.05) and FAS expression increased by 63 +/- 8% (P < 0.05); however, LPL expression was not altered. DGAT1, FAS, and LPL mRNA expression were not significantly changed after metformin treatment. The treatment of mice with rosiglitazone also resulted in an increase in adipose expression of DGAT1 by 2- to 3-fold, as did the treatment of 3T3 F442A adipocytes in vitro with thiazolidinediones. These data support a more global concept suggesting that adipose lipid storage functions to prevent peripheral lipotoxicity.     

Genetic Diversity and Chemical Polymorphism of Some Thymus Species

To ascertain whether there are chemical and genetic relationships among some Thymus species and also to determine correlation between these two sets of data, the essential‐oil composition and genetic variability of six populations of Thymus including: T. daenensis ?elak. (two populations), T. fallax Fisch . & C.A.Mey ., T. fedtschenkoi Ronniger , T. migricus Klokov & Des .‐Shost ., and T. vulgaris L. were analyzed by GC and GC/MS, and also by randomly amplified polymorphic DNA (RAPD). Thus, 27 individuals were analyzed using 16 RAPD primers, which generated 264 polymorphic scorable bands and volatiles isolated by distillation extraction were subjected to GC and GC/MS analyses. The yields of oils ranged from 2.1 to 3.8% (v/w), and 34 components were identified, amounting to a total percentage of 97.8–99.9%. RAPD Markers allowed a perfect distinction between the different species based on their distinctive genetic background. However, they did not show identical clustering with the volatile‐oil profiles.     

Association of interleukin-18 gene variants with susceptibility to visceral leishmaniasis in Iranian population

Host resistance to Leishmania infection is mediated by cellular immune responses leading to macrophage activation and parasite killing. Interleukin-18 (IL-18) known as interferon-γ (IFN-γ) inducing factor, stimulates IFN-γ production by T cells. Taking into account the important role of IL-18 in the defense against visceral leishmaniasis (VL) and the known effect of IL-18 gene polymorphisms on its production, the aim of this study was to investigate the probable relationship between IL-18 gene polymorphisms and the susceptibility to VL. The study groups included 118 pediatric patients who suffered from VL and 156 non-relative healthy people as the controls from the same endemic area. IL-18 gene polymorphisms at the positions ?656 G/T, ?137 G/C and +105A/C (codon 35/3) were analyzed by polymerase chain reaction-restricted fragment length polymorphism (PCR–RFLP). The results showed that the frequency of T allele at the position -656 was significantly higher in the controls, compared with that in the patients (P = 0.047), but it couldn’t tolerate Bonferroni correction. Regarding the IL-18 genotypes, there was no significant difference between the patients and controls. Although the frequencies of ATG single haplotype and AGG/ATG double haplotype were significantly higher in the controls (P = 0.043) and the patients (P = 0.044), respectively, the two P values couldn’t tolerate Bonferroni correction. Furthermore, a strong linkage disequilibrium was observed among the ?656, ?137 and +105 single nucleotide polymorphisms of IL-18 gene (all Ps < 0.001). In conclusion, this study suggests that the inheritance of T allele at the position ?656 may be considered as a genetic factor for resistance to VL.     

Effects of pioglitazone and metformin on beta-cell function in nondiabetic subjects at high risk for type 2 diabetes

Thiazolidinediones (TZDs) and metformin decreased the incidence of diabetes in subjects at risk for developing diabetes and improved peripheral or hepatic insulin sensitivity, respectively. Whether they also directly improved beta-cell function is not clear. In vitro studies showed improved beta-cell function in response to TZDs and metformin; however, the effects of TZDs or metformin on beta-cell function in humans are still uncertain. We hypothesized that both TZDs and metformin directly affect beta-cell function. We evaluated beta-cell function and insulin sensitivity (S(I)) in subjects with impaired glucose tolerance or a history of gestational diabetes using oral and intravenous glucose tolerance tests in addition to the glucose-potentiated arginine stimulation test. In contrast to metformin, pioglitazone improved S(I), glucose tolerance, and insulin-independent glucose disposal [glucose effectiveness (S(G))]. Neither pioglitazone nor metformin significantly improved beta-cell compensation for insulin resistance [disposition index (DI)], but the change in DI significantly correlated with baseline S(I). Insulin secretion in response to arginine at maximally potentiating glucose levels (AIR(max)) tended to increase after metformin and to decrease after pioglitazone; however, when adjusted for S(I), the changes were not significant. Our results demonstrate that, in nondiabetic subjects at risk for diabetes, pioglitazone, but not metformin, significantly improved glucose tolerance by improving S(I) and S(G). We did not find any evidence that either pioglitazone or metformin improved beta-cell function. Improved beta-cell compensation was observed primarily in the subgroup of subjects that had the lowest S(I) at baseline.