mAbs: Monoclonal antibodies; EF2: elongation factor 2; ITs: Immunotoxins; DT: Diphtheria toxin; PE: Pseudomonas exotoxin; dgA: de-glycosylated A-chain of ricin; rGel: recombinant de-glycosylated form of gelonin; NKC: natural killer cells; HTR: human transferrin receptor; EGF: epidermal growth factor; GM-CSF: granulocyte-macrophage colony-stimulating factor; DAB389: truncated Diphtheria toxin; B-CCL: B-cell chronic lymphocytic leukemia; RCC: renal cell carcinoma; GVHD: Graft-versus-host disease; EGFR: epidermal growth factor receptor; AML: acute myeloid leukemia; Fab: fragment antigen-binding; dsFv: disulfide-stabilized fragment variable; scFv: single-chain fragment variable; B-ALL: B-lineage Acute Lymphoblastic Leukemia; Fv: fragment variable; HCL: hairy cell leukemia; IL-2R: Interleukin-2 receptor; CR: complete response; CLL: chronic lymphocytic leukemia; ATL: adult T-cell leukemia; DARPins: designed Ankyrin repeat proteins; pmol: picomolar; HAMA: human-anti mouse antibody.

Background:Pseudomonas aeruginosa is a leading cause of nosocomial infections worldwide. Resistance of P. aeruginosa strains to the broad-spectrum cephalosporins may be caused by extended-spectrum β-lactamases (ESBLs).Objectives:The aim of this study was to determine the antimicrobial resistance patterns and prevalence of PER-1 and VEB-1 type genes among ESBL producing strains of P. aeruginosa.Material and Methods:A total of 106 P. aeruginosa isolates were collected from two university hospitals in Hamadan, Iran, during a7-month study (2009). The antimicrobial susceptibility of isolates was determined by disc diffusion method and interpreted according to the clinical and laboratory standards institute (CLSI) recommendations. Production of ESBL was determined by combined disk test and presence of PER-1 and VEB-1 type ESBL genes was identified by PCR.Results:The resistance against broad-spectrum cephalosporins and monobactames were: cefepime (97%), cefotaxime (92.5%) ceftazidime (51%), and aztreonam (27%). Ciprofloxacin (91.5%), imipenem (84.9%) and meropenem (82.1%) were the most effective anti-pseudomonas agents in this study. The results revealed that 88.7% of the isolates were multidrug resistant, 58.25% of those were ESBL positive. Sixteen (26.6%), 9 (15%) and 3 (5%) strains among ESBL-producing strains contained blaPER-1, blaVEB and blaPER-1-blaVEB, respectively.Conclusions:This study highlighted the need to establish antimicrobial resistance surveillance networks for P. aeruginosa to determine the appropriate empirical treatment regimens. The high prevalence of multidrug resistance and production of ESBLs in P. aeruginosa isolates confirms the necessity of protocols considering these issues in the hospitals.

Recombinant antibodies are increasingly being employed as therapeutic agents especially in combination with anti-cancer drugs. The single-chain antibody fragments are small antigen-binding proteins which provide the most commonly used antibody formats for diagnostic and therapeutic purposes. These antibody fragments have more rapid tumor penetration and clearance from the serum relative to full-length monoclonal antibodies. There are in vitro antibody-display technologies such as phage display, cell surface display, ribosome display and mRNA display that can be used to isolate high specificity and affinity single-chain antibodies against a wide variety of targets. We review these strategies for generation of stable and active antibody fragments in the present article.

Lung cancer is the leading cause of cancer-related mortality with about 1.6 million deaths every year worldwide. Gene mutations and overexpression of oncogenes play a central role in malignant transformation in NSCLC. Conventional approaches for treatments of NSCLC have shown low levels of success while showing severe side effects. Target therapy using siRNA has recently emerged as a new strategy for cancer treatment by specific targeting of genes involved in the development and metastasis of cancer. This article dedicated to an update review of molecular targets could potentially be used for target therapy of lung cancer using SiRNA technology.

No abstract

Overexpression of epidermal growth factor receptor (EGFR) plays a significant role in the development and metastasis of many solid tumors. Strategies based on anti-EGFR immunotoxins have shown promising results in several studies, but immunogenicity of antibody and toxin moieties is a limitation of this type of therapeutics. In the present study, a novel humanized anti-EGFR immunotoxin (huscFv-PE25) was developed by genetic fusing of a humanized anti-EGFR single-chain variable fragment (huscFv) with a modified Pseudomonas aeruginosa exotoxin A (PE25KDEL). The reactivity and toxicity of this immunotoxin with tumor cells were assessed by dot-blot, enzyme-linked immunosorbent assay, and MTT procedures. Results of enzyme-linked immunosorbent assay and dot-blot assay indicated that the immunotoxin recognizes and efficiently binds to EGFR-overexpressing tumor cells. MTT assay showed a specific growth-inhibitory effect of huscFv-PE25 on EGFR-overexpressing A431 cells, without any inhibitory effect on EGFR-negative cells. In conclusion, the results of this study indicated that huscFv-PE25 can recognize and exert an inhibitory effect on EGFR-overexpressing cancer cells, despite its smaller size and lower immunogenicity. This may provide a basis for the development of novel clinical therapeutic agents against EGFR-overexpressing tumor cells.

The results of this study revealed that co-expression of chaperones with hscFv leads to remarkable increase in the solubility of the recombinant hscFv, which could be of great consideration for large scale production of recombinant single chain antibodies.

Epidermal growth factor receptor (EGFR) as a transmembrane tyrosine kinase receptor frequently overexpresses in tumors with epithelial origin. The L2 domain from extracellular part of EGFR is involved in ligand binding and the blockage of this domain prevents activation of related signaling pathways. This study was aimed to develop a novel human scFv against EGFR L2 domain as a promising target for cancer therapy. The L2 recombinant protein was purified and used for panning a human scFv phage library (Tomlinson I). In this study, a novel screening strategy was applied to select clones with high binding and enrichment of rare specific phage clones of the L2 protein. After five biopanning rounds several specific clones were isolated which among them one phage clone with high binding was purified for further analysis. The specific interaction of selected clone against target antigen was confirmed by ELISA and western blotting. Immunofluorescence staining showed that purified scFv binds to A431 cells surface, displaying EGFR surface receptor. In the present study, we isolated for the first time a novel human scFv against EGFR L2 domain. This study can be the groundwork for developing more effective diagnostic and therapeutic agents against EGFR overexpressing cancers using this novel human anti-L2 ScFv.