A multi-stage process including transient polyploidization and EMT precedes the emergence of chemoresistent ovarian carcinoma cells with a dedifferentiated and pro-inflammatory secretory phenotype.
DNA-damaging drugs induce a plethora of molecular and cellular alterations in tumor cells, but their interrelationship is largely obscure. Here, we show that carboplatin treatment of human ovarian carcinoma SKOV3 cells triggers an ordered sequence of events, which precedes the emergence of mitotic chemoresistant cells. The initial phase of cell death after initiation of carboplatin treatment is followed around day 14 by the emergence of a mixed cell population consisting of cycling, cell cycle-arrested and senescent cells. At this stage, giant cells make up >80% of the cell population, p21 (CDKN1A) in strongly induced, and cell numbers remain nearly static. Subsequently, cell death decreases, p21 expression drops to a low level and cell divisions increase, including regular mitoses of giant cells and depolyploidization by multi-daughter divisions. These events are accompanied by the upregulation of stemness markers and a pro-inflammatory secretory phenotype, peaking after approximately 14 days of treatment. At the same time the cells initiate epithelial to mesenchymal transition, which over the subsequent weeks continuously increases, concomitantly with the emergence of highly proliferative, migratory, dedifferentiated, pro-inflammatory and chemoresistant cells (SKOV3-R). These cells are anchorage-independent and grow in a 3D collagen matrix, while cells on day 14 do not survive under these conditions, indicating that SKOV3-R cells were generated thereafter by the multi-stage process described above. This process was essentially recapitulated with the ovarian carcinoma cell line IGROV-1. Our observations suggest that transitory cells characterized by polyploidy, features of stemness and a pro-inflammatory secretory phenotype contribute to the acquisition of chemoresistance.
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Verena
V
Rohnalter
Cell Imaging Core Facility, Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Katrin
K
Roth
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Florian
F
Finkernagel
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Till
T
Adhikary
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Julia
J
Obert
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Kristina
K
Dorzweiler
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Maike
M
Bensberg
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Sabine
S
Müller-Brüsselbach
Institute of Molecular Biology and Tumor Research (IMT), Center for Tumor Biology and Immunology, Philipps University, Marburg 35043, Germany.
Rolf
R
Müller
D000970:Antineoplastic Agents / Q000494:pharmacology; D016190:Carboplatin / Q000494:pharmacology*; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D054337:Cell Dedifferentiation / Q000187:drug effects* / Q000235:genetics; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D016922:Cellular Senescence / Q000187:drug effects / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects* / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011123:Polyploidy; D013997:Time Factors; D059008:Time-Lapse Imaging
D000970:Antineoplastic Agents; C400423:Ciz1 protein, human; D018836:Inflammation Mediators; D009687:Nuclear Proteins; D016190:Carboplatin
chemoresistance; epithelial-mesenchymal transition (EMT); giant cancer cells; polyploidy; senescence-associated secretory phenotype (SASP)