Silencing of NADPH Oxidase 4 Attenuates Hypoxia Resistance in Neuroblastoma Cells SH-SY5Y by Inhibiting PI3K/Akt-Dependent Glycolysis

Abstract

Hypoxia-induced chemoresistance is a major obstacle in the development of effective cancer therapy. In our study, the reversal abilities of NADPH oxidase 4 (NOX4) silence on the hypoxia resistance and the potential mechanism were investigated. Our data showed that the expression of NOX4 was up-regulated in human neuroblastoma cells SHSY-5Y under hypoxia condition time-dependently. Knockdown of NOX4 expression by siRNA inhibited glycolysis induced by hypoxia through decreasing the expression of glycolysis related proteins (HIF-1α, LDHA, PDK1), decreasing glucose uptake, lactate production, ROS production while increasing mitochondria membrane potential. Moreover, NOX4 silence inhibited cell viability under hypoxia condition through suppressing cell proliferation and proliferation related proteins (Ki67, PCNA) compared with hypoxia 24h + siRNA NC group. Further, western blot experiments exhibited that NOX4 siRNA could down-regulate the rate of p-Akt/Akt. Treatment with PI3K/Akt signaling activator IGF-I blocked while treatment with Akt inhibitor Perifosine enhanced the inhibitory effect of si-NOX4 on glycolysis and cell viability. In summary, knockdown of NOX4 had an ability of reversing hypoxia resistance, and the major mechanism is considered to be the inhibition of glycolysis and cell viability via PI3K/Akt signaling pathway. Therefore, NOX4 could be a novel target against hypoxia resistance in neuroblastoma.

NOX4 Signaling Mediates Cancer Development and Therapeutic Resistance through HER3 in Ovarian Cancer Cells

“…In this study, as showed in the overall model of Figure 7 , we showed that NOX4 expression levels were increased in human ovarian cancer tissues, compared with the adjacent tissues, and higher expression of NOX4 was associated with poor survival and progression of ovarian cancer. Interestingly, this study showed that HIF-1α directly regulated NOX4 expression, which is consistent with the previous report that NOX4 was induced by hypoxia [ 20 , 21 ]. NOX4 was reported to produce different isoforms by cutting off exons containing NAD(P)H/FADH binding regions.…”

Downregulation of microRNA‑25‑3p inhibits the proliferation and promotes the apoptosis of multiple myeloma cells via targeting the PTEN/PI3K/AKT signaling pathway

“…PTEN is a key upstream of the PI3K/Akt signaling pathway (36,38) and activated PI3K/Akt signaling contributes to cell growth and apoptosis in a number of tumors, including MM (37). In MM, PI3K/Akt is constitutively active and contributes to the the proliferation of MM cells, which suggests that the inhibition of this pathway may be a potential therapeutic approach for MM (39)(40)(41)(42). Jiang et al demonstrated that miR-20a inhibited the proliferation, migration and apoptosis of MM cells, and that these effects were associated with PI3K/AKT signaling pathway inactivation (37).…”

Quantitative ubiquitylome analysis and crosstalk with proteome/acetylome analysis identified novel pathways and targets of perifosine treatment in neuroblastoma

“…As perifosine is an Akt inhibitor, there is evidence that perifosine impedes glycolysis and therefore improve chemosensitivity in non-small lung cancer cells (50). In a recently published study of human NB cells (SH-SY-5Y), researchers found that silencing of NADPH oxidase 4 inhibited glycolysis, and this was enhanced when combined with perifosine reversing hypoxia induced chemo-resistance (51). However, the underlying mechanism remains unclear.…”