NOX1 Inhibition Attenuates the Development of a Pro-Tumorigenic Environment in Experimental Hepatocellular Carcinoma

Abstract

Background The poor prognosis of advanced HCC and limited efficacy of current systemic treatments emphasize the need for new or combined targeted therapies. The development of HCC is a multistage process in which liver injury appears in a complex microenvironment associated with oxidative stress. NOX enzymes are the main source of ROS during hepatocarcinogenesis and NOX1 in particular has shown correlation with poor prognosis of HCC patients. This study evaluates the effect of pharmacological NOX1 inhibition on the development and progression of HCC and its effect on the tumor microenvironment.Methods The in vitro cytotoxic effects of the NOX1 inhibitor GKT771 (Genkyotex) on human Huh7 and Hep3B and murine Hepa1-6 HCC cell lines, and murine macrophages were evaluated via MTT, LDH activity and CaspGlo® assays. In order to induce in vivo HCC, male SV129 wild-type mice received weekly IP injections of diethylnitrosamine (DEN) (35 mg/kg) for 20-25 weeks. Mice were treated with vehicle or GKT771 (30 mg/kg) via oral gavage. Treatment duration and frequency (daily or twice daily) varied in the preventive and therapeutic studies. mRNA transcript levels in the tumor and liver tissue were determined by RT-qPCR. Fibrosis was visualized by Sirius Red staining and quantified by the Metavir​ score. Results A concentration-dependent reduction in cellular activity of the human HCC cell lines without cytotoxicity was observed. GKT771 treatment reduced LPS-induced pro-inflammatory bone-marrow derived macrophage polarization. DEN injections resulted in 100% tumor formation and the induction of HCC markers which could be reduced by twice daily dosing of GKT771 at early onset of advanced HCC. DEN-induced HCC resulted in an upregulation of pro-inflammatory, angiogenic and fibrotic markers which was less pronounced in GKT771 treated mice in all treatment regimens. In line, liver fibrosis was induced in HCC mice and this to a lesser extend upon GKT771 treatment.Conclusion NOX1 inhibition showed to be safe and well tolerated and was able to attenuate the induction of a pro-inflammatory, angiogenic and pro-fibrotic microenvironment suggesting that this might be a promising adjuvant therapeutic strategy in the treatment of advanced HCC.

SMOX expression predicts the prognosis of non-small cell lung cancer

“…It was found that SMOX had highlevel expression in most of the 24 pairs of NSCLC tumor and paracancerous tissues, while it had low-level expression in paracancerous tissues (Figure 8A,B) (19). Notably, in 24 pairs of NSCLC tumor tissues and paracancerous tissues, SMOX had high-level expression in tumor tissues and lowlevel expression in normal tissues determined by RT-PCR analysis (Figure 8C) (20,21). Immunohistochemical analysis showed that SMOX was indeed highly expressed in 155 NSCLC patients (Figure 8D) (22).…”