title: Overexpression of the dynein light chain km23-1 in human ovarian carcinoma cells inhibits tumor formation in vivo and causes mitotic delay at prometaphase/metaphase.
abstract: km23-1 is a dynein light chain that was identified as a TGFβ receptor-interacting protein. To investigate whether km23-1 controls human ovarian carcinoma cell (HOCC) growth, we established a tet-off inducible expression system in SKOV-3 cells in which the expression of km23-1 is induced upon doxycycline removal. We found that forced expression of km23-1 inhibited both anchorage-dependent and anchorage-independent growth of SKOV-3 cells. More importantly, induction of km23-1 expression substantially reduced the tumorigenicity of SKOV-3 cells in a xenograft model in vivo. Fluorescence-activated cell sorting analysis of SKOV-3 and IGROV-1 HOCCs demonstrated that the cells were accumulating at G2/M. Phospho-MEK, phospho-ERK and cyclin B1 were elevated, as was the mitotic index, suggesting that km23-1 suppresses HOCCs growth by inducing a mitotic delay. Immunofluorescence analyses demonstrated that the cells were accumulating at prometaphase/metaphase with increases in multipolar and multinucleated cells. Further, although the mitotic spindle assembly checkpoint protein BubR1 was present at the prometaphase kinetochore in Dox+/- cells, it was inappropriately retained at the metaphase kinetochore in Dox- cells. Thus, the mechanism by which high levels of km23-1 suppress ovarian carcinoma growth in vitro and inhibit ovary tumor formation in vivo appears to involve a BubR1-related mitotic delay.
authors.affiliation: Department of Biochemistry and Molecular Biology, Penn State Hershey College of Medicine, Hershey, PA 17033, USA.
authors.forename: Nageswara R
authors.initials: NR
authors.lastname: Pulipati
authors.forename: Qunyan
authors.initials: Q
authors.lastname: Jin
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Baodong
authors.initials: B
authors.lastname: Sun
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Pandey
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Huber
authors.forename: Wei
authors.initials: W
authors.lastname: Ding
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Mulder
mesh_terms: D000818:Animals; D002455:Cell Division; D045744:Cell Line, Tumor; D056445:Cytoplasmic Dyneins / Q000378:metabolism*; D004398:Dyneins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008677:Metaphase; D051379:Mice; D008819:Mice, Nude; D008938:Mitosis; D009368:Neoplasm Transplantation; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000517:prevention & control; D049468:Prometaphase; D014183:Transplantation, Heterologous; D015854:Up-Regulation
chemical_list: C504797:DYNLRB1 protein, human; D056445:Cytoplasmic Dyneins; D004398:Dyneins