Naproxen Induces Cell-Cycle Arrest and Apoptosis in Human Urinary Bladder Cancer Cell Lines and Chemically Induced Cancers by Targeting PI3K

Abstract

Naproxen ((S)-6-methoxy-α-methyl-2-naphthaleneacetic acid) is a potent nonsteroidal anti-inflammatory drug that inhibits both COX-1 and COX-2 and is widely used as an over-the-counter medication. Naproxen exhibits analgesic, anti-pyretic, and anti-inflammatory activities. Naproxen, as well as other NSAIDS, has been reported to be effective in the prevention of urinary bladder cancer in rodents. However, potential targets other than the COX isozymes have not been reported. We examined potential additional targets in urinary bladder cancer cells and in rat bladder cancers. Computer kinase profiling results suggested that phosphatidylinositol 3-kinase (PI3-K) is a potential target for naproxen. In vitro kinase assay data revealed that naproxen interacts with PI3-K and inhibits its kinase activity. Pull-down binding assay data confirmed that PI3-K directly binds with naproxen in vitro and ex vivo. Western blot data showed that naproxen decreased phosphorylation of Akt, and subsequently decreased Akt signaling in UM-UC-5 and UMUC-14 urinary bladder cancer cells. Furthermore, naproxen suppressed anchorage-independent cell growth and decreased cell viability by targeting PI3-K in both cell lines. Naproxen caused an accumulation of cells at the G1 phase mediated through CDK4, cyclin D1 and p21. Moreover, naproxen induced significant apoptosis, accompanied with increased levels of cleaved caspase 3, caspase 7, and poly (ADP-ribose) polymerase (PARP) in both cell types. Naproxen-induced cell death was mainly due to apoptosis in which a prominent down-regulation of Bcl-2 and up-regulation of Bax were involved. Naproxen also caused apoptosis and inhibited Akt phosphorylation in rat urinary bladder cancers induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine (OH-BBN).

Prevention of Chemically Induced Urinary Bladder Cancers by Naproxen: Protocols to Reduce Gastric Toxicity in Humans Do Not Alter Preventive Efficacy

“…However, the magnitude of the changes in AKT and PI3K phosphorylation are limited, and would be difficult to use as a biomarker clinically. The changes observed in caspases and in AKT and PI3K phosphorylation are in agreement with our recent cell culture studies employing NPX (38). Since rats were treated for five days with NPX it may be that all of the observed changes are secondary to alterations in prostaglandins following COX inhibition.…”

Simultaneous presentation of pancreatic cancer in a genetically unrelated couple

“…Naproxen can induce cell apoptosis by downregulating bcl-2 and upregulating Bax 23. A similar outcome with reduced risk of pancreatic cancer in patients using non-steroidal anti-inflammatory drugs has been demonstrated in one study 24.…”

Genipin inhibits the growth of human bladder cancer cells via inactivation of PI3K/Akt signaling

“…Qin et al (26) demonstrated that (-)-epigallocatechin-3-gallate, a component of green tea, promotes apoptosis in T24 bladder cancer cells through the inhibition of the PI3K/Akt pathway. Kim et al (27) revealed that naproxen [(S)-6-methoxy-α-methyl-2-naphthaleneacetic acid] induces cell-cycle arrest and apoptosis in bladder cancer cells through the inhibition of PI3K activity. To confirm the role of the PI3K/Akt pathway in mediating the action of genipin, constitutively active Akt was overexpressed in bladder cancer cells prior to genipin exposure.…”