TY - JOUR
T1 - The relative resistance of non-cycling cells in 9L multicellular spheroids to spirohydantoin mustard
AU - Sano, Yoshinori
AU - Hoshino, Takao
AU - Bjerkvig, Rolf
AU - Deen, Dennis F.
N1 - Funding Information:
Accepted 13 April 1983. *Supported by NIH Grants CA-13525 and CA-19992 anda gift from the Morris Stulsaft Foundation. §To whom requests for reprints should be addressed at: Brain Tumor Research Center, 783 HSW, University of California, San Francisco, CA 94143, U.S.A. Abbreviations: SHM, spirohydantoin mustard; CENU, chloroethylnitrosourea; PLD, potentially lethal damage; EBSS, Earle’s balanced salt solution; BCNU, 1,3-bis(2-chloroethyl)-1-nitrosourea; MEM, Eagle’s minimum essential medium: CMEM, complete growth medium; [rH]-TdR, tritiated thymidine; CFE, colony-forming efficiency; PE, plating efficiency; SF, surviving fraction; DMSO, dimethyl 5ulfoxide; FCM, flow cytometry.
PY - 1983/10
Y1 - 1983/10
N2 - Surviving fractions of 9L spheroid cells treated with 1.5, 3.0 and 6.0 μg/ml of spirohydantoin mustard (SHM) decreased when assayed 6 hr after treatment but increased thereafter. Flow cytometric analysis showed that exponentially growing 9L monolayer cells treated with SHM accumulated at the G2/M border within 24 hr. Cells dissociated from spheroids treated with 3 and 6.0 μg/ml of SHM accumulated at the G2/M border during the first 24 hr after treatment and remained there for the next 12 hr. However, 50% of the cells remained at the 2C DNA peak. Spheroid cells with 2C DNA content 24 hr after treatment were assumed to be non-cycling cells at the time of treatment, and cells that accumulated at the G2/M peak appeared to be cycling cells at the time of treatment; approximately 50% of cells in untreated 9L spheroids are in the noncycling pool. G1 and/or early S phase 9L cells in exponential growth elutriated immediately after treatment with SHM had significantly lower (P > 0.001) plating efficiencies than 9L cells in S and G2/M phases. When spheroids were dissociated, elutriated and plated for colony-forming efficiency 24 hr after treatment with 3 μg/ml of SHM, fractions enriched in 2C DNA content had significantly higher (P > 0.001) plating efficiencies than elutriated cells enriched in 4C DNA. These results indicate that SHM is less effective against non-cycling 9L spheroid cells with 2C DNA content than against cycling 9L spheroids cells.
AB - Surviving fractions of 9L spheroid cells treated with 1.5, 3.0 and 6.0 μg/ml of spirohydantoin mustard (SHM) decreased when assayed 6 hr after treatment but increased thereafter. Flow cytometric analysis showed that exponentially growing 9L monolayer cells treated with SHM accumulated at the G2/M border within 24 hr. Cells dissociated from spheroids treated with 3 and 6.0 μg/ml of SHM accumulated at the G2/M border during the first 24 hr after treatment and remained there for the next 12 hr. However, 50% of the cells remained at the 2C DNA peak. Spheroid cells with 2C DNA content 24 hr after treatment were assumed to be non-cycling cells at the time of treatment, and cells that accumulated at the G2/M peak appeared to be cycling cells at the time of treatment; approximately 50% of cells in untreated 9L spheroids are in the noncycling pool. G1 and/or early S phase 9L cells in exponential growth elutriated immediately after treatment with SHM had significantly lower (P > 0.001) plating efficiencies than 9L cells in S and G2/M phases. When spheroids were dissociated, elutriated and plated for colony-forming efficiency 24 hr after treatment with 3 μg/ml of SHM, fractions enriched in 2C DNA content had significantly higher (P > 0.001) plating efficiencies than elutriated cells enriched in 4C DNA. These results indicate that SHM is less effective against non-cycling 9L spheroid cells with 2C DNA content than against cycling 9L spheroids cells.
UR - http://www.scopus.com/inward/record.url?scp=0020555585&partnerID=8YFLogxK
U2 - 10.1016/0277-5379(93)90015-W
DO - 10.1016/0277-5379(93)90015-W
M3 - Article
C2 - 6685631
AN - SCOPUS:0020555585
SN - 0277-5379
VL - 19
SP - 1451
EP - 1456
JO - European Journal of Cancer and Clinical Oncology
JF - European Journal of Cancer and Clinical Oncology
IS - 10
ER -