title: Clonal cell populations unresponsive to radiosensitization induced by telomerase inhibition.
abstract: A combination of a radiotherapeutic regimen with telomerase inhibition is valuable when tumor cells are to be sensitized to radiation. Here, we describe cell clones unresponsive to radiosensitization after telomere shortening. After extensive division of individual transformed clones of mTERC-/- cells, about 22% of clones were unresponsive to radiosensitization even though telomerase action was inhibited. The telomere lengths of unsensitized mTERC-/- clones were reduced, as were those of most sensitized clones. However, the unsensitized clones did not exhibit chromosomal end-to-end fusion to the extent noted in all sensitized clones. Thus, a defense mechanism preventing telomere erosion is operative even when telomeres become shorter under conditions of telomerase deficiency, and results in unresponsiveness to the radiosensitization generally mediated by telomere shortening.
authors.affiliation: Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences, Seoul 139-706, Republic of Korea.
authors.forename: Yeun-Jin
authors.initials: YJ
authors.lastname: Ju
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Shin
authors.forename: Jeong-Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Kyoung-Mi
authors.initials: KM
authors.lastname: Juhn
authors.forename: Seon Rang
authors.initials: SR
authors.lastname: Woo
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Han
authors.forename: Sang-Gu
authors.initials: SG
authors.lastname: Hwang
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Hong
authors.forename: Chang-Mo
authors.initials: CM
authors.lastname: Kang
authors.forename: Young-Do
authors.initials: YD
authors.lastname: Yoo
authors.forename: Won-Bong
authors.initials: WB
authors.lastname: Park
authors.forename: Myung-Haing
authors.initials: MH
authors.lastname: Cho
authors.forename: Gil Hong
authors.initials: GH
authors.lastname: Park
authors.forename: Kee-Ho
authors.initials: KH
authors.lastname: Lee
mesh_terms: D000818:Animals; D002999:Clone Cells; D005347:Fibroblasts / Q000201:enzymology / Q000528:radiation effects; D051379:Mice; D008817:Mice, Mutant Strains; D011836:Radiation Tolerance; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000235:genetics; D016615:Telomere / Q000378:metabolism*
chemical_list: D019098:Telomerase