Nucleolar Changes and Fibrillarin Redistribution Following Apatone Treatment of Human Bladder Carcinoma Cells

Abstract

(KS) S U M M A R Y Ascorbate and menadione (Apatone) in a ratio of 100:1 kills tumor cells by autoschizis. In this study, vitamin-induced changes in nucleolar structure were evaluated as markers of autoschizis. Human bladder carcinoma (T24) cells were overlain with vitamins or with culture medium. Supernatants were removed at 1-hr intervals from 1 to 4 hr, and the cells were washed with PBS and prepared for assay. Apatone produced marked alterations in nucleolar structure including redistribution of nucleolar components, formation of ringshaped nucleoli, condensation and increase of the proportion of perinucleolar chromatin, and the enlargement of nucleolar fibrillar centers. Immunogold labeling of the nucleolar rRNA revealed a granular localization in treated and sham-treated cells, and immunogold labeling of the rDNA revealed a shift from the fibrillar centers to the condensed perinucleolar chromatin. Fibrillarin staining shifted from the fibrillar centers and adjacent regions to a more homogeneous staining of the entire nucleolus and was consistent with the percentage of autoschizic cells detected by flow cytometry. Because autoschizis entails sequential reactivation of DNase I and DNase II, and because the fibrillarin redistribution following DNase I and Apatone treatment is identical, it appears that the nucleolar and fibrillarin changes are markers of autoschizis. (J Histochem Cytochem 58:635-651, 2010)

The TERE1 protein interacts with mitochondrial TBL2: Regulation of trans‐membrane potential, ROS/RNS and SXR target genes

“…This is in agreement with menaquinone 0 s capacity to facilitate electron transport in anaerobic states [Tielens et al, 2002;Nowicka and Kruk, 2010] and findings for the Drosophila homolog of TERE1, heix, in which expression enhanced mitochondrial electron transport and ATP production [Bhalerao and Clandinin, 2012;Vos et al, 2012]. This shows that TERE1 expression can mimic some of the reported effects of pharmacological dosing of vitamins K-2 and K-3 that lead to different types of growth inhibition, autoschizis, necrosis, or apoptosis in different tumor cell lines [Lamson and Plaza, 2003;Shibayama-Imazu et al, 2008;Jamison et al, 2010]. We also found that ectopic TERE1 can increase caspase 3/7 activity two-fold.…”

“…Mutations in human TERE1 cause Schnyder 0 s Corneal Dystrophy, (SCD), in which patients suffer from elevated corneal cholesterol and lipid deposition [Weiss et al, 2007;Nickerson et al, 2010]. Vitamin K-2, also known as menaquinone, and vitamin K-3, also known as menadione, are redox-cycling and alkylating quinones known to inhibit the growth of tumor cells via activating oxidative stress responsive signaling cascades such as EGFR and AKT ( [Nishikawa et al, 1999;Lamson and Plaza, 2003;Gilloteaux et al, 2010] and references therein). Vitamin K-2, also known as menaquinone, and vitamin K-3, also known as menadione, are redox-cycling and alkylating quinones known to inhibit the growth of tumor cells via activating oxidative stress responsive signaling cascades such as EGFR and AKT ( [Nishikawa et al, 1999;Lamson and Plaza, 2003;Gilloteaux et al, 2010] and references therein).…”

“…In parallel, TERE1 was also re-discovered as a long sought after prenyltransferase enzyme in the vitamin K-2 biosynthetic pathway in which vitamin K-1 is converted to K-2 with K-3 as an intermediate [Nakagawa et al, 2010]. Vitamin K-2, also known as menaquinone, and vitamin K-3, also known as menadione, are redox-cycling and alkylating quinones known to inhibit the growth of tumor cells via activating oxidative stress responsive signaling cascades such as EGFR and AKT ( [Nishikawa et al, 1999;Lamson and Plaza, 2003;Gilloteaux et al, 2010] and references therein). Vitamin K-2 is also a potent activator of SXR nuclear hormone receptor signaling which regulates transcription of multiple genes in pathways such as lipid metabolism and cholesterol efflux, a finding consistent with the SCD phenotype in human TERE1 mutants [Zhou et al, 2009a].…”

The Bladder Tumor Suppressor Protein TERE1 (UBIAD1)Modulates Cell Cholesterol: Implications for Tumor Progression

“…We did observe an increase in H 2 O 2 in fresh lysates from Ad-TERE1-infected J82 cells consistent with TERE1-mediated synthesis of vitamins K-2 or K-3. Both vitamin K-2 and K-3 are redox-cycling and alkylating quinones known to generate oxidative stress (superoxide and H 2 O 2 ), alkylate thiols and amines (O'Brien, 1991) and lead to different types of growth inhibition, autoschizis, necrosis, or apoptosis (Lamson and Plaza, 2003;Shibayama-Imazu et al, 2006;Jamison et al, 2010). This also suggests the possibility that TERE1 expression may be an oxidative stress liability that is selected against during tumor cell metabolic reprogramming to the invasive phenotype.…”

Gold nanoparticles induce nuclear damage in breast cancer cells, which is further amplified by hyperthermia

“…Furthermore, nucleolar size correlates with the aggressiveness of breast tumors, and enlarged nucleoli correspond to a poor clinical outcome [23][24][25], validating the use of nucleoli as targets in cancer therapy [28]. The subcellular redistribution of the nucleolar protein fibrillarin has been linked to autoschizis in cancer cells [29]; fibrillarin was therefore selected to monitor the impact of GNPs on nucleolar organization. Like nucleoli, molecular chaperones, exemplified by the constitutively synthesized hsc70, and the nuclear transporter cellular apoptosis susceptibility protein (CAS [30]) are critical to nuclear functions and essential for cancer cell viability, proliferation, or migration [31][32][33][34][35][36].…”