3-Acetyl-bis(2-chloro-4-nitrophenyl)triazene is a potent antitumor agent that induces oxidative stress and independently activates the stress-activated protein kinase/c-Jun NH2-terminal kinase pathway

Abstract

Previously, we described the synthesis and biological activity of a new class of anticancer molecules that preferentially target malignant cells and may serve as potential antitumor agents. Among several synthesized agents, we selected 3-acetyl-1,3-bis(2-chloro-4-nitrophenyl)-1-triazene (8b) as a representative of the group of 4-nitro-substituted 1,3-diaryltriazenes. The aim of this study was to further investigate the mechanism of cell response to the 8b compound. The HeLa human cervical carcinoma cell line was used as an experimental model to further investigate the mechanism of cell response to the 8b compound. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay was used to address cell survival, and western blot (immunoblotting) was used for the expression of relevant proteins after 8b drug exposure. The pretreatment of HeLa cells with salubrinal, a specific inhibitor of endoplasmic reticulum (ER) stress, confirmed the importance of ER stress in apoptosis induced by 8b. We also demonstrate that 8b triggers the activation of stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) in a time-dependent and dose-dependent manner. Moreover, the inhibition of SAPK/JNK activity by JNK II before 8b treatment increased the survival rate of HeLa cells relative to survival in the presence of 8b alone, indicating the importance of this kinase in cell death. The simultaneous inhibition of ER stress induction and SAPK/JNK activation increased the survival of HeLa cells upon 8b treatment more than inhibition of both pathways independently, suggesting the separate triggering of both signaling pathways. Our data indicate that cytotoxic activity of the novel compound 8b is based on its ability to induce ER stress and SAPK/JNK signaling pathways independently, driving cells to cell death.

Biological Activity of Flavonoids and Rare Sesquiterpene Lactones Isolated From Centaurea ragusina L.

“…For that purpose, HeLa cells were either pre-treated with 5 mM NAC, the precursor for GSH synthesis, for 2 h prior to treatment with compound 5 or overnight with a specific inhibitor of GSH synthesis, i.e., 0.001 mM BSO. The conditions used were tested previously to be effective ( Brozovic et al, 2008 ; Brozovic et al, 2014 ). The obtained data showed that an increased level of GSH protects HeLa cells from ragusinin’s toxicity ( Figure 8A ).…”

“…This redox cycling of GSH plays a role in the maintenance of cellular redox homeostasis. GSH binds to endogenous and diverse xenobiotic electrophilic compounds either catalytically, through the action of glutathione S-transferase, or non-catalytically ( Townsend and Tew, 2003 ; Brozovic et al, 2014 ). The formed GSH conjugates can be exported from cells, resulting in the loss of cellular GSH.…”

Discovery of ‘click’ 1,2,3-triazolium salts as potential anticancer drugs

“…Literature data indicate that diverse compounds can induce cell damage due to formation of ROS. 38 , 39 ROS may irreversibly oxidize DNA, nucleic acids, proteins, and lipids, thereby representing the primary source of damage in biological systems that may eventually lead to cell death. 40 , 41 Accordingly, we directly measured the induction of ROS formation following the treatment with 2b.…”

Organometallic ruthenium(II)-arene complexes with triphenylphosphine amino acid bioconjugates: Synthesis, characterization and biological properties

“…For that purpose, HeLa cells were either pre-treated with specific inhibitor of GSH synthesis, 0.01μg/mL buthionine sulfoximine (BSO) overnight or with precursor of GSH synthesis, 5 mM N-acetylcysteine (NAC) for two hours prior to treatment with 2 pG , 2 pA , 2 mG or 2 mA . The conditions used were tested previously to be effective (Brozovic et al 2008, Brozovic et al 2014. The obtained data showed decreased survival of HeLa cells in the case when GSH was depleted by BSO and increased survival of cells in the case when the level of GSH was increased due to the NAC (Figure 5A-D).…”