Restriction of cisplatin induction of acute apoptosis to a subpopulation of cells in a three-dimensional carcinoma culture model.
Cisplatin is a clinically important chemotherapeutical agent used to treat epithelial malignancies. High concentrations (20-100 microM) of cisplatin have been used in numerous studies to induce apoptosis of carcinoma cells grown in monolayer culture over 24-48 hr. These conditions may not be relevant to 3-D tumor tissue in vivo and the importance of apoptosis for tumor response is controversial. We here studied the effects of cisplatin on a 3-D colon carcinoma in vitro model (multicellular spheroids). Cisplatin at a dose of 40 microM induced active caspase-3 preferentially in the peripheral 30 microm cell layer of spheroids, mainly during late stages (72-96 hr). The p53 response to cisplatin was also largely confined to peripheral cell layers. Despite the use of a high cisplatin concentration, a significant fraction of the cells in the spheroids survived treatment. A high proportion of surviving cells stained positive for beta-galactosidase, a marker of premature senescence. Cells growth-arrested by cisplatin treatment showed a higher spontaneous cell death rate than untreated proliferating cells. We propose that acute apoptosis is of minor significance for the overall response of carcinoma cells to cisplatin treatment.
Fayad
Walid
W
Department of Oncology and Pathology, Karolinska Institute and Hospital, Cancer Center Karolinska, Stockholm, Sweden.
Brnjic
Slavica
S
Berglind
Daniel
D
Blixt
Susanna
S
Shoshan
Maria C
MC
Berndtsson
Maria
M
Olofsson
Maria Hägg
MH
Linder
Stig
S
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D018929:Cell Culture Techniques; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D004249:DNA Damage / Q000187:drug effects; D006801:Humans; D007124:Immunoenzyme Techniques; D051379:Mice; D016513:Mice, SCID; D018874:Spheroids, Cellular; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D016159:Tumor Suppressor Protein p53; D002945:Cisplatin