title: KIF1Bbeta functions as a haploinsufficient tumor suppressor gene mapped to chromosome 1p36.2 by inducing apoptotic cell death.
abstract: Deletion of the distal region of chromosome 1 frequently occurs in a variety of human cancers, including aggressive neuroblastoma. Previously, we have identified a 500-kb homozygously deleted region at chromosome 1p36.2 harboring at least six genes in a neuroblastoma-derived cell line NB1/C201. Among them, only KIF1Bbeta, a member of the kinesin superfamily proteins, induced apoptotic cell death. These results prompted us to address whether KIF1Bbeta could be a tumor suppressor gene mapped to chromosome 1p36 in neuroblastoma. Hemizygous deletion of KIF1Bbeta in primary neuroblastomas was significantly correlated with advanced stages (p = 0.0013) and MYCN amplification (p < 0.001), whereas the mutation rate of the KIF1Bbeta gene was infrequent. Although KIF1Bbeta allelic loss was significantly associated with a decrease in KIF1Bbeta mRNA levels, its promoter region was not hypermethylated. Additionally, expression of KIF1Bbeta was markedly down-regulated in advanced stages of tumors (p < 0.001). Enforced expression of KIF1Bbeta resulted in an induction of apoptotic cell death in association with an increase in the number of cells entered into the G2/M phase of the cell cycle, whereas its knockdown by either short interfering RNA or by a genetic suppressor element led to an accelerated cell proliferation or enhanced tumor formation in nude mice, respectively. Furthermore, we demonstrated that the rod region unique to KIF1Bbeta is critical for the induction of apoptotic cell death in a p53-independent manner. Thus, KIF1Bbeta may act as a haploinsufficient tumor suppressor, and its allelic loss may be involved in the pathogenesis of neuroblastoma and other cancers.
authors.affiliation: Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan.
authors.forename: Arasambattu K
authors.initials: AK
authors.lastname: Munirajan
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Ando
authors.forename: Akira
authors.initials: A
authors.lastname: Mukai
authors.forename: Masato
authors.initials: M
authors.lastname: Takahashi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Suenaga
authors.forename: Miki
authors.initials: M
authors.lastname: Ohira
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Koda
authors.forename: Toru
authors.initials: T
authors.lastname: Hirota
authors.forename: Toshinori
authors.initials: T
authors.lastname: Ozaki
authors.forename: Akira
authors.initials: A
authors.lastname: Nakagawara
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics / Q000378:metabolism; D016195:G2 Phase / Q000235:genetics; D005784:Gene Amplification; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D019656:Loss of Heterozygosity; D051379:Mice; D008819:Mice, Nude; D000071447:N-Myc Proto-Oncogene Protein; D009368:Neoplasm Transplantation; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: C091053:KIF1B protein, human; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D016547:Kinesins