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

Singh RK, Lange TS, Kim KK, Singh AP, Vorsa N, Brard L - Br. J. Cancer (2008)

Bottom Line: In a screen performed by the National Cancer Institute (NCI) (NCI(60) cancer cell-line assay) NB7M (NSC746077) reduced growth up to 100% with an IC(50) between 0.1 and 10 microM depending on the cell line studied.Subcytotoxic doses of NB7M inhibited DNA synthesis, caused G1-phase cell-cycle arrest and upregulated p27 expression.In addition, NB7M acts as a growth/cell-cycle-suppressing agent and may be developed as a potential therapeutic drug to treat ovarian cancer.

View Article: PubMed Central - PubMed

Affiliation: Molecular Therapeutics Laboratory, Program in Women's Oncology, Department of Obstetrics and Gynecology, Women and Infants' Hospital, Brown University, Providence, RI 02905, USA.

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 microM), in contrast to control cells (TCL-1 and HTR-8; IC(50) approximately 15 microM). In a screen performed by the National Cancer Institute (NCI) (NCI(60) cancer cell-line assay) NB7M (NSC746077) reduced growth up to 100% with an IC(50) between 0.1 and 10 microM 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, IKK alpha), transcription factor NF-kappaB, 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.

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Design concept and cytotoxicity of indolyl ethyl isothiocyanate NB7M. (A) Synthesis and structure of 7Me-IEITC derivative NB7M. (see Materials and Methods; Supplementary Information). (B) Comparative analysis of the cytotoxic effect of NB7M in various human cancer and control cell lines. SKOV-3, OVCAR-3 (ovarian epithelial adenocarcinomas), PC-3 (prostate adenocarcinoma), BxPC-3 (pancreatic adenocarcinoma), A-431 (epidermoid carcinoma), HeLa (endometrial), TCL-1 (trophoblasts) and HTR-8 (first-trimester cytotrophoblasts) human cell lines were treated with various concentrations (0–20 μM) of NB7M for 48 h. The MTS viability assay was carried out as described (Materials and Methods). Experiments were performed in triplicates; data are expressed as the mean of the triplicate determinations (X±s.d.) of a representative experiment in % cell viability of samples with untreated cells (100%).
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fig1: Design concept and cytotoxicity of indolyl ethyl isothiocyanate NB7M. (A) Synthesis and structure of 7Me-IEITC derivative NB7M. (see Materials and Methods; Supplementary Information). (B) Comparative analysis of the cytotoxic effect of NB7M in various human cancer and control cell lines. SKOV-3, OVCAR-3 (ovarian epithelial adenocarcinomas), PC-3 (prostate adenocarcinoma), BxPC-3 (pancreatic adenocarcinoma), A-431 (epidermoid carcinoma), HeLa (endometrial), TCL-1 (trophoblasts) and HTR-8 (first-trimester cytotrophoblasts) human cell lines were treated with various concentrations (0–20 μM) of NB7M for 48 h. The MTS viability assay was carried out as described (Materials and Methods). Experiments were performed in triplicates; data are expressed as the mean of the triplicate determinations (X±s.d.) of a representative experiment in % cell viability of samples with untreated cells (100%).

Mentions: The primary objective of this study was to further optimise the structural attributes of 7Me-IEITC (Figure 1A). The rationale of adding a tert-butyl carbamate group (converting the compound into NB7M; Figure 1A) was to protect the amino group in the hope of increasing the bioavailability as the lipophilic protection of a nitrogen atom in various anticancer drugs enhances tissue permeability (Serova et al, 2007). In a recent study, we reported an increased cytotoxicity and rapid induction of apoptosis by NB7M in nervous system cancer cells in vitro (Brard et al, 2008). In the present study, we (1) compared the cytotoxic effects of NB7M on ovarian and other tumour-derived cell lines, (2) identified the mechanisms of programmed cell death of SKOV-3 cells induced by NB7M (3) analysed the expression of key MAPKs and other prosurvival markers and (4) reported inhibitory effects of subcytotoxic doses of NB7M on cell-cycle progression of SKOV-3 cells substantiated by studies on the expression of check-point regulators of the cell cycle.


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

Singh RK, Lange TS, Kim KK, Singh AP, Vorsa N, Brard L - Br. J. Cancer (2008)

Design concept and cytotoxicity of indolyl ethyl isothiocyanate NB7M. (A) Synthesis and structure of 7Me-IEITC derivative NB7M. (see Materials and Methods; Supplementary Information). (B) Comparative analysis of the cytotoxic effect of NB7M in various human cancer and control cell lines. SKOV-3, OVCAR-3 (ovarian epithelial adenocarcinomas), PC-3 (prostate adenocarcinoma), BxPC-3 (pancreatic adenocarcinoma), A-431 (epidermoid carcinoma), HeLa (endometrial), TCL-1 (trophoblasts) and HTR-8 (first-trimester cytotrophoblasts) human cell lines were treated with various concentrations (0–20 μM) of NB7M for 48 h. The MTS viability assay was carried out as described (Materials and Methods). Experiments were performed in triplicates; data are expressed as the mean of the triplicate determinations (X±s.d.) of a representative experiment in % cell viability of samples with untreated cells (100%).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2600706&req=5

fig1: Design concept and cytotoxicity of indolyl ethyl isothiocyanate NB7M. (A) Synthesis and structure of 7Me-IEITC derivative NB7M. (see Materials and Methods; Supplementary Information). (B) Comparative analysis of the cytotoxic effect of NB7M in various human cancer and control cell lines. SKOV-3, OVCAR-3 (ovarian epithelial adenocarcinomas), PC-3 (prostate adenocarcinoma), BxPC-3 (pancreatic adenocarcinoma), A-431 (epidermoid carcinoma), HeLa (endometrial), TCL-1 (trophoblasts) and HTR-8 (first-trimester cytotrophoblasts) human cell lines were treated with various concentrations (0–20 μM) of NB7M for 48 h. The MTS viability assay was carried out as described (Materials and Methods). Experiments were performed in triplicates; data are expressed as the mean of the triplicate determinations (X±s.d.) of a representative experiment in % cell viability of samples with untreated cells (100%).
Mentions: The primary objective of this study was to further optimise the structural attributes of 7Me-IEITC (Figure 1A). The rationale of adding a tert-butyl carbamate group (converting the compound into NB7M; Figure 1A) was to protect the amino group in the hope of increasing the bioavailability as the lipophilic protection of a nitrogen atom in various anticancer drugs enhances tissue permeability (Serova et al, 2007). In a recent study, we reported an increased cytotoxicity and rapid induction of apoptosis by NB7M in nervous system cancer cells in vitro (Brard et al, 2008). In the present study, we (1) compared the cytotoxic effects of NB7M on ovarian and other tumour-derived cell lines, (2) identified the mechanisms of programmed cell death of SKOV-3 cells induced by NB7M (3) analysed the expression of key MAPKs and other prosurvival markers and (4) reported inhibitory effects of subcytotoxic doses of NB7M on cell-cycle progression of SKOV-3 cells substantiated by studies on the expression of check-point regulators of the cell cycle.

Bottom Line: In a screen performed by the National Cancer Institute (NCI) (NCI(60) cancer cell-line assay) NB7M (NSC746077) reduced growth up to 100% with an IC(50) between 0.1 and 10 microM depending on the cell line studied.Subcytotoxic doses of NB7M inhibited DNA synthesis, caused G1-phase cell-cycle arrest and upregulated p27 expression.In addition, NB7M acts as a growth/cell-cycle-suppressing agent and may be developed as a potential therapeutic drug to treat ovarian cancer.

View Article: PubMed Central - PubMed

Affiliation: Molecular Therapeutics Laboratory, Program in Women's Oncology, Department of Obstetrics and Gynecology, Women and Infants' Hospital, Brown University, Providence, RI 02905, USA.

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 microM), in contrast to control cells (TCL-1 and HTR-8; IC(50) approximately 15 microM). In a screen performed by the National Cancer Institute (NCI) (NCI(60) cancer cell-line assay) NB7M (NSC746077) reduced growth up to 100% with an IC(50) between 0.1 and 10 microM 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, IKK alpha), transcription factor NF-kappaB, 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.

Show MeSH
Related in: MedlinePlus