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

Antiproliferative activity and p53 upregulation effects of chalcones on human breast cancer cells

Chalcones are valuable structures for drug discovery due to their broad bioactivity spectrum. In this study, we evaluated 20 synthetic chalcones against estrogen-receptor-positive breast cancer cells (MCF-7 line) and triple-negative breast cancer (TNBC) cells (MDA-MB-231 line). Antiproliferative screening by MTT assay resulted in two most active compounds: 2-fluoro-4’-aminochalcone (11) and 3-pyridyl-4’-aminochalcone (17). Their IC₅₀ values ranged from 13.2 to 34.7 µM against both cell lines. Selected chalcones are weak basic compounds and maintained their antiproliferative activity under acidosis conditions (pH 6.7), indicating their resistance to ion-trapping effect. The mode of breast cancer cells death was investigated and chalcones 11 and 17 were able to induce apoptosis rather than necrosis in both lines. Antiproliferative target investigations with MCF-7 cells suggested 11 and 17 upregulated p53 protein expression and did not affect Sp1 protein expression. Future studies on chalcones 11 and 17 can define their in vivo therapeutic potential.

Targeted regulation of PI3K/Akt/mTOR/NF-κB signaling by indole compounds and their derivatives: mechanistic details and biological implications for cancer therapy

Indole compounds, found in cruciferous vegetables, are potent anti-cancer agents. Studies with indole-3-carbinol (I3C) and its dimeric product, 3,3'-diindolylmethane (DIM) suggest that these compounds have the ability to deregulate multiple cellular signaling pathways, including PI3K/Akt/mTOR signaling pathway. These natural compounds are also effective modulators of downstream transcription factor NF-κB signaling which might help explain their ability to inhibit invasion and angiogenesis, and the reversal of epithelial-to-mesenchymal transition (EMT) phenotype and drug resistance. Signaling through PI3K/Akt/mTOR and NF-κB pathway is increasingly being realized to play important role in EMT through the regulation of novel miRNAs which further validates the importance of this signaling network and its regulations by indole compounds. Here we will review the available literature on the modulation of PI3K/Akt/mTOR/NF-κB signaling by both parental I3C and DIM, as well as their analogs/derivatives, in an attempt to catalog their anticancer activity.

7 Methyl indole ethyl isothiocyanate causes ROS mediated apoptosis and cell cycle arrest in endometrial cancer cells

OBJECTIVE

Chemotherapy options for advanced endometrial cancer are limited and newer therapeutic agents are urgently needed. This study describes the therapeutic potential of 7 Methyl-indole ethyl isothiocyanate (7Me-IEITC) in endometrial cancer cell lines.

METHODS

7Me-IEITC was synthesized in our laboratory. The cell viability of 7Me-IEITC treated ECC-1 and KLE endometrial cancer cell was determined by MTS assay. Morphology and apoptosis were further confirmed by DAPI-staining and TUNEL assay. The measurement of reactive oxygen species (ROS), mitochondrial transmembrane depolarization potential (ΔΨm) and cell cycle phase was determined by FACS analysis. Expression of proteins involved in apoptosis, survival and cell-cycle progression was analyzed by Western blotting.

RESULTS

7Me-IEITC reduced the viability of the ECC-1 and KLE cancer cell-lines (IC(50)~2.5-10 μM) in a dose dependent fashion. 7Me-IEITC treatment caused mitochondrial transmembrane potential reduction, elevated the production of ROS, leading to activation of apoptosis in endometrial cancer KLE and ECC-1 cells. 7Me-IEITC treatment activated Bad, suppressed Bcl2 phosphorylation followed by PARP-1 deactivation and caspase 3 and 7 activation. 7Me-IEITC treatment arrested the progression of KLE cells in S-phase and caused CDC25 and cyclin-D1 downregulation. Pre-treatment with ascorbic acid abrogated 7Me-IEITC induced apoptosis in ECC-1 and KLE cells, suggesting that 7Me-IEITC mediated cytotoxicity is primarily through ROS production.

CONCLUSION

7Me-IEITC demonstrated promising cytotoxic effects in endometrial cancer cell line model.

Description of the cytotoxic effect of a novel drug Abietyl-Isothiocyanate on endometrial cancer cell lines

The objective of the present study was to determine the in-vitro effect of Abietyl-Isothiocyanate (ABITC), a representative of a new class of anti-cancer drugs, on endometrial cancer (EC) cell lines. ABITC at concentrations ≥1 μM displayed dose-dependent and selective cytotoxicity to EC cell lines (ECC-1, AN3CA, RL95-2) in comparison to other cancer cell lines. After treatment with ABITC, ECC-1 unlike control cells displayed hallmark features of apoptosis including chromatin condensation and nuclear fragmentation. At concentrations below the IC50, ABITC exerted anti-proliferative effects by blocking cell-cycle progression through G0/G1 and S-phase. In addition, cells attempted to counteract drug treatment by pro-survival signaling such as deactivation of JNK/SAPK and p38 MAPK and activation of AKT and ErK1/2. ABITC also altered EGF-receptor phosphorylation. At a concentration of 5 μM ABITC generated an excess amount of reactive oxygen species (ROS) and displayed pro-apoptotic signaling such as activation of caspase-8, JNK-SAPK and deactivation of PARP-1. Co-treatment with an antioxidant blocked the drug effects by reducing ROS generation, cytotoxicity and pro-apoptotic signaling. In summary, novel isothiocyanate ABITC is an anti-proliferative and selectively cytotoxic drug to EC cells in-vitro. Key mechanisms during cell death are predominantly correlated to excess generation of ROS. We suggest the further development of ABITC as a potential therapeutic by studying the drug efficacy in EC in-vivo models.

Sulforaphane induces cell cycle arrest by protecting RB-E2F-1 complex in epithelial ovarian cancer cells

Background

Sulforaphane (SFN), an isothiocyanate phytochemical present predominantly in cruciferous vegetables such as brussels sprout and broccoli, is considered a promising chemo-preventive agent against cancer. In-vitro exposure to SFN appears to result in the induction of apoptosis and cell-cycle arrest in a variety of tumor types. However, the molecular mechanisms leading to the inhibition of cell cycle progression by SFN are poorly understood in epithelial ovarian cancer cells (EOC). The aim of this study is to understand the signaling mechanisms through which SFN influences the cell growth and proliferation in EOC.

Results

SFN at concentrations of 5 - 20 μM induced a dose-dependent suppression of growth in cell lines MDAH 2774 and SkOV-3 with an IC50 of ~8 μM after a 3 day exposure. Combination treatment with chemotherapeutic agent, paclitaxel, resulted in additive growth suppression. SFN at ~8 μM decreased growth by 40% and 20% on day 1 in MDAH 2774 and SkOV-3, respectively. Cells treated with cytotoxic concentrations of SFN have reduced cell migration and increased apoptotic cell death via an increase in Bak/Bcl-2 ratio and cleavage of procaspase-9 and poly (ADP-ribose)-polymerase (PARP). Gene expression profile analysis of cell cycle regulated proteins demonstrated increased levels of tumor suppressor retinoblastoma protein (RB) and decreased levels of E2F-1 transcription factor. SFN treatment resulted in G1 cell cycle arrest through down modulation of RB phosphorylation and by protecting the RB-E2F-1 complex.

Conclusions

SFN induces growth arrest and apoptosis in EOC cells. Inhibition of retinoblastoma (RB) phosphorylation and reduction in levels of free E2F-1 appear to play an important role in EOC growth arrest.

A coumarin derivative (RKS262) inhibits cell-cycle progression, causes pro-apoptotic signaling and cytotoxicity in ovarian cancer cells

Coumarin derivative RKS262 belongs to a new class of potential anti-tumor agents. RKS262 was identified by structural optimization of Nifurtimox which is currently undergoing phase II clinical trials to treat high-risk neuroblastoma. In a NCI(60) cell-line assay RKS262 exhibited significant cytotoxicity in ovarian cancer cells and a variety of other cell lines exceeding effects of commercial drugs such as cisplatin, 5-FU, cyclophosphamide or sapacitabine. Various leukemia cell-lines were most sensitive (GI(50): ~ 10 nM) while several non-small cell lung cancer cell lines and few cell lines from other tissues were relatively resistant (GI(50) > 1 µM) to RKS262 treatment. The mechanism of cytotoxicity was examined using ovarian cancer cell-line OVCAR-3 as a model. RKS262 treatment resulted in a reduced mitochondria-transmembrane-depolarization potential. RKS262 effects included up-regulation of apoptotic markers and were not correlated with activation of pro-apoptotic MAP-Kinases (p38, SAP/JNK). RKS262 exerted strong inhibitory effects on oncogene ras, down-regulated DNA-pk KU-80 subunit expression and caused activation of Akt. A signature effect of RKS262 is the regulation of the mitochondrial Bcl2-family pathway. Pro-apoptotic factors Bid, Bad and Bok were up-regulated while expression of pro-survival factors Bcl-xl and Mcl-1 was inhibited. Moreover, at sub-cytotoxic doses RKS262 delayed OVCAR-3 cell-cycle progression through G2 phase and up-regulated p27 while cyclin-D1 and Cdk-6 were down-regulated, indicating that RKS262 is a specific cyclin/CDK inhibitor. In summary, RKS262 has been identified as a molecule belonging to a new class of potential chemotherapeutic agents affecting the viability of multiple cancer cell-lines and causing selective adverse effects on the viability of ovarian cancer cells.