A novel indole ethyl isothiocyanate (7Me-IEITC) with anti-proliferative and pro-apoptotic effects on platinum-resistant human ovarian cancer cells.
OBJECTIVE
A novel indole ethyl isothiocyanate derivative (7Me-IEITC) was defined as a potent growth-suppressing agent to cell lines derived from ovarian cancers. Key mechanisms of the cellular response in vitro were studied and suggest a potential of 7Me-IEITC as a therapeutic drug.


METHODS
The viability of ovarian cancer cell lines (SKOV-3, OVCAR-3) in comparison to pancreatic and prostate cancer cell lines, primary fibroblast and immortalized trophoblasts after treatment with 7Me-IEITC was analyzed. Morphological and apoptotic responses of SKOV-3 were studied by fluorescence microscopy (DAPI staining, TUNEL assay). SKOV-3 proliferation was estimated by a standardized BrdU incorporation assay. The phosphorylation of MAP-Kinases, pro-survival factors and the activation of caspases and PARP-1 were analyzed by western blotting. Changes of the mitochondrial transmembrane-potential and in cell-cycle progression were studied by FACS analysis. MAP-Kinase and caspase inhibitors were employed in cytotoxicity studies.


RESULTS
7Me-IEITC selectively reduced the viability of SKOV-3, OVCAR-3, BXPC-3 and PC-3 cells (IC(50) values < or = 5 microM), while the viability of fibroblasts or trophoblasts remained un-affected at concentrations below 20 microM. 7Me-IEITC treatment down-regulated pro-survival kinases and transcription factors (STAT-3, IKKalpha and NF-kappaB), caused rapid loss of the mitochondrial transmembrane-potential and inactivation of PARP-1 along with activation of caspases. The use of p38 MAP-Kinase-and caspase inhibitors suppressed the cytotoxicity of the drug. 7Me-IEITC acted as an anti-proliferative agent and arrested the cell-cycle progression of SKOV-3 in G2/M phase.


CONCLUSIONS
7Me-IEITC is a potent and growth-suppressing agent to cell lines derived from ovarian cancers by causing deactivation of survival signals, apoptosis, and cell-cycle arrest.
Singh
Rakesh K
RK
Molecular Therapeutics Laboratory, Program in Women's Oncology, Department of Obstetrics and Gysnecology, Women and Infants' Hospital, Brown University, Providence, RI 02905, USA.
Lange
Thilo S
TS
Kim
Kyu Kwang
KK
Shaw
Sunil K
SK
Brard
Laurent
L
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D017209:Apoptosis / Q000187:drug effects*; D015415:Biomarkers / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D017953:Isocyanates / Q000494:pharmacology*; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000503:physiopathology; D010984:Platinum / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000503:physiopathology
C529237:7-methyl-indole ethyl isothiocyanate; D015415:Biomarkers; D007211:Indoles; D017953:Isocyanates; D010984:Platinum; D020928:Mitogen-Activated Protein Kinases