Allelic imbalance on chromosome 2q and alterations of the caspase 8 gene in neuroblastoma

Abstract

We previously reported a high incidence of loss of heterozygosity (LOH) on chromosome 2q33 in neuroblastoma (NB), observed in various types of human cancers including lung cancer, head and neck cancer and follicular thyroid carcinoma. To better elucidate the role of chromosome 2q aberrations in NB, we examined common allelic imbalance (AI) regions on chromosome 2q in 82 NB patients using 10 polymorphic microsatellite markers. AI on 2q was detected in 26 (32%) of 82 NB cases. There was a distinct common AI region between the D2S115 and D2S307 markers on 2q33. The distance between these markers was about 2.0 cM. Recently, the caspase 8 and caspase 10 genes, both of which encode cystein protease, were mapped to chromosome 2q33. Since the common AI region on 2q33 includes the caspase 8 and caspase 10 genes, the alterations of these genes were examined further. Absent or reduced expression of caspase 8 and caspase 10 were found in 19 (70%) of 27 and two (7%) of 27 NB cell lines by reverse transcription-polymerase chain reaction, respectively. A missense mutation was detected at codon 96, GCT (Alanine) to GTT (Valine), of the caspase 8 gene in one of the NB cell lines lacking caspase 8 expression. Thirteen (68%) of 19 cell lines lacking caspase 8 expression displayed methylation of the CpG island of the caspase 8 gene, whereas only one (13%) of eight cell lines with caspase 8 expression showed caspase 8 methylation (P=0.031). Furthermore, there was a signi®cant association between AI at 2q33 and loss of caspase 8 expression (P=0.026). These results indicated that there was a tumor suppressor gene in the common AI region on chromosome 2q33 involved in the pathogenesis of a subset of NB. It is possible that the caspase 8 gene is one of the candidate tumor suppressor genes for NB and inactivation of this gene plays an important role in the tumorigenesis of NB through mainly its methylation. Oncogene (2001) 20, 4424 ± 4432.

Caspase-9 and Apaf-1 are expressed and functionally active in human neuroblastoma tumor cell lines with 1p36 LOH and amplified MYCN

“…All stage IV and IVS patients without ampli®ed MYCN from this study may have had a single methylated allele, but the remaining allele continued to express caspase-8 (Teitz et al, 2000). Similar observations were made in an independent genetic study of a cohort of Japanese neuroblastoma patient tumors (Takita et al, 2001).…”

“…We found that a high percentage of stage IV neuroblastoma cell lines with MYCN ampli®cation (i.e., 15/16 or 94%), as well as stage IV primary patient tumor samples with MYCN ampli®ca-tion (i.e., 10/16 or 63%), did not express caspase-8 mRNA (Teitz et al, 2000;Takita et al, 2001). Caspase-8 is a cysteine protease that has an essential and non-redundant role in receptor-mediated cell death (Sca di et al, 1997).…”

Aberrant activation of ALK kinase by a novel truncated form ALK protein in neuroblastoma

“…The SCMC-N series was established in our laboratory. 33 The SJNB series and UTP-N-1 cells were provided by Dr AT Look and Dr A Inoue, respectively. Other cell lines were obtained from the Japanese Cancer Resource Cell Bank (http://cellbank.nibio.go.jp/wwwjcrbj.htm).…”

Molecular mediators of cell death in multistep carcinogenesis: a path to targeted therapy

“…Interestingly, loss of caspase-8 is commonly observed in disseminated neuroblastoma. 74,75 Figure 2 The sonic hedghog (shh) signaling pathway. The transmembrane shh receptor ptc functions to inhibit smo.…”