Systemic Approaches Identify a Garlic-Derived Chemical, Z-ajoene, as a Glioblastoma Multiforme Cancer Stem Cell-Specific Targeting Agent

Abstract

Glioblastoma multiforme (GBM) is one of the most common brain malignancies and has a very poor prognosis. Recent evidence suggests that the presence of cancer stem cells (CSC) in GBM and the rare CSC subpopulation that is resistant to chemotherapy may be responsible for the treatment failure and unfavorable prognosis of GBM. A garlic-derived compound, Z-ajoene, has shown a range of biological activities, including anti-proliferative effects on several cancers. Here, we demonstrated for the first time that Z-ajoene specifically inhibits the growth of the GBM CSC population. CSC sphere-forming inhibition was achieved at a concentration that did not exhibit a cytotoxic effect in regular cell culture conditions. The specificity of this inhibitory effect on the CSC population was confirmed by detecting CSC cell surface marker CD133 expression and biochemical marker ALDH activity. In addition, stem cell-related mRNA profiling and real-time PCR revealed the differential expression of CSC-specific genes, including Notch, Wnt, and Hedgehog, upon treatment with Z-ajoene. A proteomic approach, i.e., reverse-phase protein array (RPPA) and Western blot analysis, showed decreased SMAD4, p-AKT, 14.3.3 and FOXO3A expression. The protein interaction map (http://string-db.org/) of the identified molecules suggested that the AKT, ERK/p38 and TGFβ signaling pathways are key mediators of Z-ajoene's action, which affects the transcriptional network that includes FOXO3A. These biological and bioinformatic analyses collectively demonstrate that Z-ajoene is a potential candidate for the treatment of GBM by specifically targeting GBM CSCs. We also show how this systemic approach strengthens the identification of new therapeutic agents that target CSCs.

Inactivation of AKT, ERK and NF-κB by genistein derivative, 7-difluoromethoxyl-5,4′-di-n-octylygenistein, reduces ovarian carcinoma oncogenicity

“…Various molecules are associated with tumor development. For example, phosphorylation of AKT, activation of ERK1 and ERK2, and NF-κBp65 proteins lead to cancer cell development (24). In the present study, we ascertained whether a newly synthesized potential anticancer genistein analogue, DFOG, possesses inhibitory effects on p-AKT and p-ERK1/2 expression, and NF-κB activity, as well as on the suppression of oncogenicity in vitro in SKOV3-derived OVCSLCs.…”

“…Since the FoxO3a function is closely associated with OVCSLC oncogenicity inhibition related to suppressed AKT and/or ERK and/or NF-κB pathway (1,24,25), whether oncogenicity reduction by DFOG in vitro depended on FoxO3a expression in OVCSLCs from SKOV3 cells was assessed. Fig.…”

Selective Targeting of Cancer Stem Cells by 2-Aminodihydroquinoline Analogs

“…16) After 48 h of treatment, MAPK signaling was suppressed (phosphorylated extracellular signal-regulated kinase (pErk)/Erk) by both chemicals dose dependently. Akt signaling did not change differently by these two compounds either (data not shown).…”

“…The bulk cell culture and CSC culture and analyses of sphere formation inhibition and cytotoxicity was decribed previously. 16) Briefly, the bulk cultured cell toxicity was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay following 3 d of cultured in FBS containing (10%) medium, with or without the compounds. The bulk cultured cells were seeded onto a well of 96 well plates (2000/well) before the drug treatment.…”

“…The bulk cultured cells were seeded onto a well of 96 well plates (2000/well) before the drug treatment. CSCs (1500/a 96 well) were cultured in suspension in poly(2-hydroxyethyl methacrylate) coated 96 well plate 16) with CSC specific medium, described previously 12) with or without the compounds. The CSC spheres were counted when the most of the sphere's diameter in control group reached to 100 µm (after 6 d).…”