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Heterogeneity Pattern of Apoptosis Mediators in Cervical Carcinoma Cells
Author(s) -
GarcíaAguiar Israel,
Del MoralHernández Oscar,
MartínezCastillo Macario,
BonillaMoreno Raúl,
VillegasSepúlveda Nicolás
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb157
Subject(s) - rna splicing , biology , alternative splicing , messenger rna , intron , microbiology and biotechnology , gene , gene expression , cancer cell , apoptosis , rna , genetics , cancer
Alternative splicing is one important regulatory posttranscriptional mechanism for control of gene expression. It produces several mature messenger RNAs (mRNAs) from single immature pre‐messenger RNA (pre‐mRNA) by using alternatively donor or acceptor splicing sites. Viruses use this posttranscriptional mechanism to increase their coding capacity, because they usually contain small genomes. The infection with the Human Papillomavirus (HPV), mainly with the types 16 (HPV‐16) and 18 (HPV‐18), is etiologically related to cervical cancer. The HPV transcripts are bicistronic or polycistronic and contain suboptimal splicing sites, which favor alternative splicing in its intron‐1; it is located in the E6/E7 oncogenes which are responsible for the transformation of host epithelial cells. Interestingly, alternatively spliced forms of the E6/E7 oncogenes are heterogeneously expressed in tumor cells and the mechanism producing the heterogeneity is still unknown. In our laboratory, it has been observed that the E6/E7 heterogeneous profile might result of differential use of acceptor sites in different cellular contexts, for example, cervical carcinoma cells with differential expression of splicing factors. Cancer cells are heterogeneous and show differential expression profiles in some metabolic markers. This fact raises the question whether the E6/E7 splicing profile heterogeneity is produced by the same mechanisms which produce tumor cell heterogeneity. Besides, some proteins involved in apoptosis are also regulated by alternative splicing; this mechanism produces alternative proteins with altered subcellular localization, as well as antagonist or dominant‐negative functions, which affect the apoptotic cell signaling and produces the phenotype of apoptosis‐resistant cancer cells. Thus, our goal was to investigate the variation in the expression profile of apoptotic mediators among cervical carcinoma cell lines. In this work we investigate the expression of alternative splicing forms of proteins involved in apoptosis, by using RT‐PCR and western blot assays in four carcinoma cell lines: C33‐A (HPV‐), CaSki (HPV‐16), HeLa (HPV‐18) and SiHa (HPV‐16). Our results revealed that some of the alternative splicing forms of the apoptotic markers were expressed differentially in both, HPV negative or positive cervical carcinoma cells; the differentially expressed alternative transcripts not presented exact correlation with the level of proteins that they encode; all these results suggested that the expression heterogeneity was produced by a complex mechanism involving several steps of post‐transcriptional control. Support or Funding Information This work was supported in part by funds allocated to NVS by CINVESTAV and by CONACYT