Antitumor effects of low‐dose tipifarnib on the mTOR signaling pathway and reactive oxygen species production in HIF‐1α‐expressing gastric cancer cells. Issue 5 (8th April 2021)

• Record Type: Journal Article
• Authors: Egawa, Noriyuki; Tanaka, Tomokazu; Matsufuji, Shohei; Yamada, Kohei; Ito, Kotaro; Kitagawa, Hiroshi; Okuyama, Keiichiro; Kitajima, Yoshihiko; Noshiro, Hirokazu
• Is Part Of: FEBS open bio. Volume 11:Issue 5(2021)
• Page Start: 1465
• Page End: 1475
• Publication Date: 2021-04-08
• Subjects: farnesyltransferase inhibitor -- gastric cancer -- HIF‐1α -- mTOR -- ROS -- tipifarnib; Molecular biology -- Periodicals; Cytology -- Periodicals; Life sciences -- Periodicals; Biological Science Disciplines -- Periodicals; Molecular Biology -- Periodicals; Cell Biology -- Periodicals; Cytology; Life sciences; Molecular biology; Periodicals; 572.805
• DOI: 10.1002/2211-5463.13154
• Languages: English
• ISSNs: 2211-5463

Abstract

Abstract : Farnesyltransferase inhibitors (FTIs) suppress tumor aggressiveness in several malignancies by inhibiting Ras signaling. However, treatment of cells with a low dose of the FTI tipifarnib suppresses the expression of hypoxia‐inducible factor‐1α (HIF‐1α) and results in antitumor effects without inhibiting the Ras pathway. Although we previously reported that elevated HIF‐1α expression is associated with an aggressive phenotype in gastric cancer (GC), little is known about the antitumor effects of FTIs on GC. In this study, we examined the relationship between the antitumor effects of low‐dose tipifarnib and HIF‐1α expression in GC cells. Under normoxic conditions, HIF‐1α was expressed only in MKN45 and KATOIII cells. The inhibitory effect of tipifarnib on HIF‐1α was observed in HIF‐1α‐positive cells. Low‐dose tipifarnib had antitumor effects only on HIF‐1α‐positive cells both in vitro and in vivo . Furthermore, low‐dose tipifarnib inactivated ras homolog enriched in brain (Rheb)/mammalian target of rapamycin (mTOR) signaling and decreased intracellular reactive oxygen species (ROS) levels in HIF‐1α‐positive GC cells. Our results that the antitumor effects of low‐dose tipifarnib are at least partially mediated through suppression of mTOR signaling and HIF‐1α expression via inhibition of Rheb farnesylation and reduction in ROS levels. These findings suggest that low‐dose tipifarnib may be capable of exerting an antitumor effect that is dependent on HIF‐1α expression in GC cells. Tipifarnib may have potential as a novel therapeutic agent for HIF‐1α‐expressing GC exhibiting an aggressive phenotype. Abstract : Low‐dose tipifarnib has antitumor effects on gastric cancer (GC) cells via suppression of mammalian target of rapamycin signaling and reactive oxygen species production. The effects of tipifarnib depend on hypoxia‐inducible factor‐1α (HIF‐1α) expression status. HIF‐1α expression is associated with cancer aggressiveness in GC. Tipifarnib may represent a novel therapeutic agent for GC exhibiting an aggressive phenotype.