Document Detail

Quantitative measurement of human papillomavirus type 16 e5 oncoprotein levels in epithelial cell lines by mass spectrometry.
MedLine Citation:
PMID:  22740411     Owner:  NLM     Status:  MEDLINE    
The high-risk human papillomavirus type 16 (HPV-16) E5 protein (16E5) induces tumors in a transgenic mouse model and may contribute to early stages of cervical carcinogenesis. Although high-risk E5 expression is generally thought to be lost during the progression to cervical carcinoma following integration of HPV DNA into the host genome, episomal viral DNA has been documented in a subset of HPV-16-positive malignant lesions. Numerous studies have shown that transcripts that could potentially encode 16E5 are present in cervical biopsy specimens and cervical cancer cell lines, but the presence of E5 protein has been demonstrated in only two reports that have not been corroborated. In the present study, we show that trypsin cleavage of 16E5 generates a unique four-amino-acid C-terminal peptide (FLIT) that serves as a marker for E5 expression in transfected cells and epithelial cell lines containing integrated and episomal HPV-16 DNA. Following trypsin cleavage, reversed-phase chromatography and mass spectrometry (MS) were used to detect FLIT. Immunoprecipitation assays using a newly generated anti-16E5 antibody confirmed that 16E5 was solely responsible for the FLIT signal, and deuterated FLIT peptide provided an internal standard that enabled us to quantify the number of 16E5 molecules per cell. We show that 16E5 is expressed in the Caski but not in the SiHa cervical cancer cell line, suggesting that 16E5 may contribute to the malignant phenotype of some cervical cancers, even in cells exclusively containing an integrated HPV genome.
Ziad Sahab; Sawali R Sudarshan; Xuefeng Liu; YiYu Zhang; Alexander Kirilyuk; Christopher M Kamonjoh; Vera Simic; Yuhai Dai; Stephen W Byers; John Doorbar; Frank A Suprynowicz; Richard Schlegel
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-06-27
Journal Detail:
Title:  Journal of virology     Volume:  86     ISSN:  1098-5514     ISO Abbreviation:  J. Virol.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-08-10     Completed Date:  2012-11-05     Revised Date:  2014-11-11    
Medline Journal Info:
Nlm Unique ID:  0113724     Medline TA:  J Virol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  9465-73     Citation Subset:  IM    
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MeSH Terms
Amino Acid Sequence
Cell Line, Transformed
Cell Line, Tumor
Epithelial Cells / chemistry*,  metabolism
Human papillomavirus 16 / chemistry*,  genetics,  metabolism
Mass Spectrometry / methods
Molecular Sequence Data
Oncogene Proteins, Viral / analysis*,  genetics,  metabolism
Peptide Mapping
Uterine Cervical Neoplasms / chemistry,  genetics,  metabolism,  virology
Grant Support
MC_U117584278//Medical Research Council; P30 CA051008/CA/NCI NIH HHS; R01 CA106400/CA/NCI NIH HHS; R01-CA053371/CA/NCI NIH HHS
Reg. No./Substance:
0/Oncogene Proteins, Viral; 0/oncogene protein E5, Human papillomavirus type 16

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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