title: Inactivation of CHEK1 and EI24 is associated with the development of invasive cervical carcinoma: clinical and prognostic implications.
abstract: To understand the importance of frequent deletion of chromosomal 11q23.3-24.3 region in cervical carcinogenesis, alterations (deletion/methylation/mutation/expression) of the candidate genes LOH11CR2A, EI24 and CHEK1 located in the region were analyzed in 29 cervical intraepithelial neoplasia (CIN), 112 cervical carcinoma (CACX) samples and two CACX cell lines. The deletion frequency of these genes was low in CIN than in CACX [CIN: CHEK1: 28%, EI24: 21%, LOH11CR2A: 15% and CACX: CHEK1: 51%, EI24: 41%, LOH11CR2A: 36%]. Similar trend was seen in promoter methylation of these genes [CIN: CHEK1: 10%, EI24: 3%, LOH11CR2A: 3% and CACX: CHEK1: 55%, EI24: 31%, LOH11CR2A: 14%]. Mutations of the genes are a rare event. Overall alterations (deletion and methylation) of CHEK1 and EI24 were associated with progression of CACX. Quantitative mRNA expression analysis showed reduced expression of the three genes in concordance to their molecular alterations. A shorter isoform of CHEK1 lacking exon 8, hence impaired in substrate binding capacity, was found in two samples. Immunohistochemical analysis showed nuclear expression of Chek1, p-Chek1 and Ei24 in tumor tissues, whereas the cell lines exhibited both nuclear and cytoplasmic expression of Chek1 and Ei24, as is also evident from Western blot analysis suggesting differential localization of the proteins. Alterations of CHEK1 and EI24 coupled with tumor stage and early sexual debut (≤ 19 years) predicted worst prognosis. Thus, our data suggest that inactivation of EI24 and CHEK1 through two independent mechanisms contributes to the development of CACX.
authors.affiliation: Department of Oncogene Regulation, Chittaranjan National Cancer Institute, Kolkata, India.
authors.forename: Dipanjana
authors.initials: D
authors.lastname: Mazumder Indra
authors.forename: Sraboni
authors.initials: S
authors.lastname: Mitra
authors.forename: Ratnesh Kumar
authors.initials: RK
authors.lastname: Singh
authors.forename: Sankhadeep
authors.initials: S
authors.lastname: Dutta
authors.forename: Anup
authors.initials: A
authors.lastname: Roy
authors.forename: Ranajit Kumar
authors.initials: RK
authors.lastname: Mondal
authors.forename: Partha Sarathi
authors.initials: PS
authors.lastname: Basu
authors.forename: Susanta
authors.initials: S
authors.lastname: Roychoudhury
authors.forename: Chinmay Kumar
authors.initials: CK
authors.lastname: Panda
mesh_terms: D000328:Adult; D051017:Apoptosis Regulatory Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D002880:Chromosomes, Human, Pair 11; D019175:DNA Methylation; D018450:Disease Progression; D005260:Female; D020868:Gene Silencing; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D011379:Prognosis; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000235:genetics*; D012008:Recurrence; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000401:mortality; D002578:Uterine Cervical Dysplasia / Q000235:genetics
chemical_list: D051017:Apoptosis Regulatory Proteins; C402592:EI24 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C109969:VWA5A protein, human; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1