ABSTRACT
INTRODUCTION: Single nucleotide polymorphisms (SNPs) of DNA repair and apoptosis genes have been associated with outcome in head and neck squamous cell carcinoma (HNSCC) patients receiving radiotherapy (RT). Our goal was to conduct a candidate gene study in HNSCC patients receiving RT or chemoRT. METHODS: 122 non-resectable HNSCC patients undergoing RT (N=38) or chemoRT (N=84) between 1992 and 2006 were retrospectively analyzed. ERCC1 Lys259Thr (rs735482), ERCC2 Lys751Gln (rs13181), ERCC5 His46His C>T (rs1047768), XRCC1 Arg399Gln (rs25487), TP53 Arg72Pro (rs1042522) and MDM2 309T>G (rs2279744) were analyzed on tumor DNA. SNP profile was considered to assess RT-related toxicity. RESULTS: All 120 evaluable patients experienced RT-related toxicity at any time. Among them, 83% had G3-4 acute side-effects during RT, mainly dysphagia, mucositis, epithelitis and/or xerostomia (DMEX). 28/105 patients (27%) had early G3-4 toxicity up to 3months after the end of RT. 29/96 patients (30%) had G3-4 late toxicity thereafter. The presence of G allele of MDM2 or Thr allele of ERCC1 was associated with a significantly higher risk of acute and/or early DMEX toxicity. The MDM2 309GG genotype was linked to a higher risk of acute G3-4 dermatitis. The ERCC5 TT genotype was associated with more frequent G3-4 late cervical skin fibrosis or xerostomia. Pro allele of TP53 72 was associated with a higher risk of G3-4 osteoradionecrosis. CONCLUSION: Relevant SNPs in DNA repair (ERCC1 and ERCC5) and apoptosis (MDM2 and TP53) genes might influence the severity of radiation-related side-effects in HNSCC patients. Prospective clinical SNP-based validation studies are needed on these bases.
Subject(s)
Apoptosis/genetics , DNA Repair/genetics , DNA-Binding Proteins/genetics , Endonucleases/genetics , Head and Neck Neoplasms/radiotherapy , Nuclear Proteins/genetics , Proto-Oncogene Proteins c-mdm2/genetics , Transcription Factors/genetics , Tumor Suppressor Protein p53/genetics , Adult , Aged , Aged, 80 and over , Female , Head and Neck Neoplasms/metabolism , Humans , Male , Middle Aged , Polymorphism, Single NucleotideABSTRACT
In fish, a layer of mucus covers the external body surface contributing therefore, among other important biological functions, to the defense system of fish. The prevention of colonization by aquatic parasites, bacteria and fungi is mediated both by immune system compounds (IgM, lysozyme, etc.) and by antibacterial peptides and polypeptides. We have recently shown that only the hydrophobic components of crude epidermal mucus of fresh water and sea water fish exhibit strong pore-forming properties, which were well correlated with antibacterial activity [N. Ebran, S. Julien, N. Orange, P. Saglio, C. Lemaitre, G. Molle, Comp. Biochem. Physiol. 122 (1999)]. Here, we have isolated novel glycosylated proteins from the hydrophobic supernatant of tench (Tinca tinca), eel (Anguilla anguilla) and rainbow trout (Oncorhynchus mykiss) mucus. The study of their secondary structure was performed by circular dichroism and revealed structures in random coil and alpha-helix in the same proportions. When reconstituted in planar lipid bilayer, they induced the formation of ion channels. This pore-forming activity was well correlated with a strong antibacterial activity (minimal inhibitory concentration < 1 microM for the three proteins) against both gram-negative and gram-positive bacteria. Our results suggest that fish secrete antibacterial glycoproteins able to kill bacteria by forming large pores (several hundreds to thousands of pS) in the target membrane.
Subject(s)
Fishes/metabolism , Glycoproteins/isolation & purification , Mucus/chemistry , Anguilla , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Circular Dichroism , Cyprinidae , Epidermis/chemistry , Glycoproteins/chemistry , Glycoproteins/pharmacology , In Vitro Techniques , Ion Channels/drug effects , Lipid Bilayers/chemistry , Membranes, Artificial , Oncorhynchus mykiss , Protein Structure, SecondaryABSTRACT
Among several biological functions, the epidermal mucus of fish may play an important role in host defense, particularly in the prevention of colonization by parasites, bacteria and fungi. In previous work, two hydrophobic proteins of 27 and 31 kDa were isolated from carp mucus. This study identified a strong antibacterial activity (0.16-0.18 microM) well correlated with pore-forming properties. Here this work was extended to other fish species, four fresh water fish and one sea water fish. After a first step of purification, water-soluble and hydrophobic material were separated, and both fractions were analyzed by SDS-PAGE and capillary electrophoresis. Only the hydrophobic component induced pore-forming activity, when reconstituted in planar lipid bilayers. This pore-forming activity was well correlated to a strong antibacterial activity against several bacteria strains. These results suggest that fish secrete antibacterial proteins able to permeabilize the membrane of the target cell and thus act as a defense barrier.
