Isothiocyanate NB7M causes selective cytotoxicity, pro-apoptotic signalling and cell-cycle regression in ovarian cancer cells

Abstract

The present report identifies indole-3-ethyl isothiocyanate NB7M as a potent cytotoxic agent with selective activity against cell lines derived from various tumour types. Ovarian cancer cell lines showed sensitivity to NB7M (60 -70% cytotoxicity at 2.5 mM), in contrast to control cells (TCL-1 and HTR-8; IC 50 B15 mM). In a screen performed by the National Cancer Institute (NCI) (NCI 60 cancer cellline assay) NB7M (NSC746077) reduced growth up to 100% with an IC 50 between 0.1 and 10 mM depending on the cell line studied. Using SKOV-3 ovarian cancer cells as a model, mechanisms of cytotoxicity were analysed. NB7M caused hallmarks of apoptosis such as PARP-1 deactivation, chromatin condensation, DNA nicks, activation of caspases-9, -8, -3, loss of mitochondrial transmembrane depolarisation potential and upregulation of pro-apoptotic mitogen activated protein kinases (p38, SAP/JNK). NB7M downregulated phosphorylation of prosurvival kinases (PI-3K, AKT, IKKa), transcription factor NF-kB, and expression of DNA-Pk and AXL receptor tyrosine kinase. Subcytotoxic doses of NB7M inhibited DNA synthesis, caused G1-phase cell-cycle arrest and upregulated p27 expression. The present report suggests that NB7M is a selective cytotoxic agent in vitro for cell lines derived from ovarian and certain other tumours. In addition, NB7M acts as a growth/cell-cycle-suppressing agent and may be developed as a potential therapeutic drug to treat ovarian cancer.

Purified cranberry proanthocyanidines (PAC-1A) cause pro-apoptotic signaling, ROS generation, cyclophosphamide retention and cytotoxicity in high-risk neuroblastoma cells

“…Viability of cell lines treated as indicated (Result Section) with PAC-1A was determined by the CellTiter 96 ® AQueous One Solution Assay (Promega Corp., Madison, WI) following the manufacturer's recommendations with suitable modifications as described previously (17).…”

“…SMS-KCNR cells were seeded into 100 mm 2 tissue culture dishes (3x10 6 cells/dish) and treated with PAC-1A (25 µg/ml) as indicated (Results). Preparation of cell lysates, PAGE and immunoblotting was carried out as described previously (17). Primary antibodies were all purchased from (Cell Signaling Technology, Beverly, MA).…”

“…Analysis of the ∆Ψm of SMS-KCNR cells (1x10 6 /well) seeded into 6-well plates and treated with 10 µg/ml PAC-1A for 12 or 24 h was carried out as described previously (17).…”

Synthetic isothiocyanate indole-3-ethyl isothiocyanate (homoITC) enhances sensitivity of human ovarian carcinoma cell lines A2780 and A2780/CP to cisplatin

“…The antitumor activities of various ITCs have been reported recently including growth inhibiting properties in human ovarian [11,19,31,32] and breast [33,34] cancers, where also their anti-angiogenic and anti-metastatic effects have been described [35,36].…”

“…The reactivity of homoITC (alkyl neutral ITC) towards thiols is similar to reactivity of PEITC (unpublished data), and it has been expected that homoITC may also act as an antiproliferative agent. Recently, homoITC and its analogs were screened to evaluate their cytotoxicity against neuroblastoma cell and human ovarian SKOV-3 and OVCAR-3 cells [18,19]. 7-methyl-indole-3-ethyl isothiocyanate had stronger cytotoxic effect then homoITC.…”