Redox-modulating agents target NOX2-dependent IKKε oncogenic kinase expression and proliferation in human breast cancer cell lines

Abstract

Oxidative stress is considered a causative factor in carcinogenesis, but also in the development of resistance to current chemotherapies. The appropriate usage of redox-modulating compounds is limited by the lack of knowledge of their impact on specific molecular pathways. Increased levels of the IKKε kinase, as a result of gene amplification or aberrant expression, are observed in a substantial number of breast carcinomas. IKKε not only plays a key role in cell transformation and invasiveness, but also in the development of resistance to tamoxifen. Here, we studied the effect of in vitro treatment with the redox-modulating triphenylmethane dyes, Gentian Violet and Brilliant Green, and nitroxide Tempol on IKKε expression and cell proliferation in the human breast cancer epithelial cell lines exhibiting amplification of IKKε, MCF-7 and ZR75.1. We show that Gentian Violet, Brilliant Green and Tempol significantly decrease intracellular superoxide anion levels and inhibit IKKε expression and cell viability. Treatment with Gentian Violet and Brilliant Green was associated with a reduced cyclin D1 expression and activation of caspase 3 and/or 7. Tempol decreased cyclin D1 expression in both cell lines, while activation of caspase 7 was only observed in MCF-7 cells. Silencing of the superoxide-generating NOX2 NADPH oxidase expressed in breast cancer cells resulted in the significant reduction of IKKε expression. Taken together, our results suggest that redox-modulating compounds targeting NOX2 could present a particular therapeutic interest in combination therapy against breast carcinomas exhibiting IKKε amplification.

Down-Regulation of SOX2 Underlies the Inhibitory Effects of the Triphenylmethane Gentian Violet on Melanoma Cell Self-Renewal and Survival

“…Previous studies indicated that GV affects ROS production by targeting NOX enzymes (Bhandarkar et al, 2009;Mukawera et al, 2015;Perry et al, 2006). Nevertheless, here we show that GV blocks melanoma cell growth in vitro and negatively affects the melanoma stem cell compartment without reducing ROS production.…”

“…GV has been used as an antibacterial, antimycotic, and antiangiogenic agent. More recently, GV has shown a strong anticancer activity both in vitro and in vivo (Bhandarkar et al, 2009;Cunniff et al, 2015;Mukawera et al, 2015;Perry et al, 2006;Yamaguchi et al, 2015) with minimal adverse effects, thus making it safe for use in humans (Arbiser, 2009). Taken together, our data suggest that GV could be a good candidate for both chemoprevention and therapeutic treatment of human melanoma.…”

“…Triphenylmethane dyes have been show to inhibit ROS production by targeting Nox4 and Nox2 in different biological contexts (Bhandarkar et al, 2009;Mukawera et al, 2015;Perry et al, 2006). Expression of NOX genes was investigated in six patient-derived primary melanoma cells, in four melanoma cell lines and in normal human epidermal melanocytes.…”

Paradoxical roles of dual oxidases in cancer biology

“…prostate [75, 76], hairy cell leukemia[77], esophageal [78], ALK lymphoma [79], and others[80, 81]. NOX2 has also been implicated in promoting the oncogenic phenotype in various cancers such as breast cancer[82], myelomonocytic leukemia[83], rectal cancer cells[84], prostate[85], and expression of NOX2 mRNA or protein was found to correlate with an invasive phenotype and poor prognosis in gastric cancer[86]. However, the explicit role for NOX-generated ROS in cancer-related outcomes is typically not demonstrated.…”

Analysis of the Effect of Gentian Violet on Apoptosis and Proliferation in Cutaneous T-Cell Lymphoma in an In Vitro Study

“…In addition to its role as an antifungal and antibacterial agent, GV has anticancer properties. [25][26][27][28][29][30] Prior work 27, [31][32][33] has found that GV inhibits nicotimamide adenine dinucleotide phosphate oxidases, NF-κB, and ANG-2 while inducing p53 and IκB in various cell types. Our current findings add to this knowledge base by detailing the association between GV and CTCL cells.…”