Time-lapse video reveals immediate heterogeneity and heritable damage among human ileocecal carcinoma HCT-8 cells treated with raltitrexed (ZD1694).
BACKGROUND
Cellular heterogeneity in drug response has important clinical implications, and is believed to develop over many generations during clonal evolution in human tumors. The purpose of this study was to determine the level of heterogeneity exhibited by sister cells soon after their birth.


METHODS
Human ileocecal carcinoma cells (HCT-8) were followed up to 11 days in vitro after a 2-h exposure to 1 microM raltitrexed (IC(95)) in a time-lapse video system.


RESULTS
Over five experiments, 414 cells were followed after exposure to raltitrexed. Immediate sterility occurred in 74% of treated cells. Only 6% of cells could produce more than two generations of offspring, and heterogeneity in drug response was seen. Comparing sister cells < 24 h old, the more proliferative sibling produced up to 73 times more offspring, with a median ratio of 9.0 (control median = 1.19). Offspring of prolific drug-treated cells had a decreased probability of division (68% compared with 92%) and an increased average interdivision time (19.0 h compared with 15.1 h).


CONCLUSIONS
Short-term exposure to raltitrexed resulted in increased interdivision times and production of sterile offspring extending seven generations. Cellular heterogeneity (difference in proliferation potential comparing drug-treated sister cells) was evident without a period of clonal evolution.
Slocum
H K
HK
Department of Pharmacology and Therapeutics and Grace Cancer Drug Center, Roswell Park Cancer Institute, Buffalo, New York 14263, USA. Harry.Slocum@RoswellPark.org
Parsons
J C
JC
Winslow
E O
EO
Broderick
L
L
Minderman
H
H
Tóth
K
K
Greco
W R
WR
Rustum
Y M
YM
D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects; D019070:Cell Lineage / Q000187:drug effects; D002999:Clone Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007078:Ileal Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D018715:Microscopy, Video / Q000379:methods*; D011336:Probability; D011799:Quinazolines / Q000633:toxicity*; D013876:Thiophenes / Q000633:toxicity*; D014407:Tumor Cells, Cultured
D000964:Antimetabolites, Antineoplastic; D011799:Quinazolines; D013876:Thiophenes; C068874:raltitrexed