Identification of tumor suppressive activity by irradiation microcell-mediated chromosome transfer and involvement of alpha B-crystallin in nasopharyngeal carcinoma.
In previous studies, we successfully refined nasopharyngeal carcinoma (NPC) critical regions (CRs) mapping to chromosome 11q13 and 11q22-23. The chromosome 11 fragment containing the 1.8 Mb NPC CR at 11q13 (CR1), the CR at 11q22.3 mapped near D11S2000 (CR2), part of the CR at 11q23.1-11q23.2 overlapping with D11S1300 and D11S1391 (CR3), and the CR at cell adhesion molecule 1 (CADM1) locus (CR4), was chosen as the chromosome 11 donor cell line for the present study. Gamma irradiation was applied to cleave this truncated chromosome into smaller fragments and a new panel of donor cells containing further deleted fragments was produced. Subclones XMCH3.2 and XMCH3.4 were chosen for subsequent transfer to HONE1 cells; each contains a single copy of deleted chromosome 11 fragment with or without CR2 and the THY1 locus, previously shown to be involved in NPC. Both resultant chromosome 11 fragments in XMCH3.2 and XMCH3.4 caused tumor suppression. The association of alpha B-crystallin (CRYAB), a gene identified as being differentially expressed by gene profiling of NPC and an immortalized nasopharyngeal epithelial cell line, and which is located near CR3, was found to be associated with tumor suppression in all the tumor-suppressive hybrids. In addition, the expression level of this gene was down-regulated in the 7 NPC cell lines and in 5 out of 14 normal/tumor tissue pairs in the present study. Both promoter hypermethylation and allelic loss may be involved in the inactivation of this gene, suggesting its possible role in NPC development.
Lung
Hong Lok
HL
Department of Biology and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (SAR), People's Republic of China.
Lo
Cathy Carfield
CC
Wong
Carmen Chak Lui
CC
Cheung
Arthur Kwok Leung
AK
Cheong
Ka Fu
KF
Wong
Nathalie
N
Kwong
Fung Mei
FM
Chan
King Chi
KC
Law
Evan Wai Lok
EW
Tsao
Sai Wah
SW
Chua
Daniel
D
Sham
Jonathan Shuntong
JS
Cheng
Yue
Y
Stanbridge
Eric J
EJ
Robertson
Gavin P
GP
Lung
Maria Li
ML
D000818:Animals; D001483:Base Sequence; D002880:Chromosomes, Human, Pair 11; D019175:DNA Methylation; D017931:DNA Primers; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018895:Microsatellite Repeats / Q000235:genetics; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D038203:alpha-Crystallin B Chain / Q000502:physiology*
D017931:DNA Primers; D038203:alpha-Crystallin B Chain