Disease relevance of Ponasterone A

• The WWOX gene was expressed in lung cancer cell lines through recombinant adenovirus (Ad) infection (Ad-WWOX), and through a drug [ponasterone A, (ponA)]-inducible system [1].
• We also used a FHIT-expressing cancer cell line (H460) induced by ponasterone A and two FHIT small interfering RNA-treated colorectal cancer cell lines (CCK81 and DLD1) [2].
• A similar block was observed when ecdysone receptor-containing RKO cells were infected with a replication-defective recombinant adenovirus containing an inducible KLF4 and treated with ponasterone A [3].
• The rate of proliferation of a stably transfected colon cancer cell line, RKO, was significantly decreased following addition of ponasterone A when compared with untreated cells [3].
• Sertoli cells isolated from 6-day postpartum mouse testes were conditionally immortalized with the simian virus 40 large tumor antigen gene (SV40-LTAg) under the control of a promoter inducible with ponasterone A, an analog of ecdysone [4].

High impact information on Ponasterone A

• Ponasterone A is a potent regulator of gene expression in cells and transgenic animals, enabling reporter genes to be turned on and off rapidly [5].
• To address the physiologic significance of 53BP2 induction, we utilized stable cell lines with a ponasterone A-regulated 53BP2 cDNA [6].
• In contrast, in vitro-transcribed-translated USP-1 and USP-2 both formed heterodimeric complexes with EcR-B1 that bound ponasterone A with the same Kd (7 x 10(-10) M) and bound to both EcRE1 and heat shock protein 27 EcRE [7].
• To additionally understand the significance of the MAD2 to mitotic checkpoint control, we established an inducible expression system in which MAD2 was induced by the addition of ponasterone A [8].
• Pharmacokinetic analysis of a highly bioactive ligand (ponasterone A), identified through screening ecdysteroids from local plants, demonstrated sustained release and transgene expression in vivo [9].

Biological context of Ponasterone A

• In current studies, the nature of the heterodimers was investigated by producing the phenotypes of the 1:1 heterodimers formed between the constitutively expressed mu-opioid receptor (MOR) and the ponasterone A-induced expression of delta-opioid receptor (DOR) in EcR293 cells [10].
• The crystal structures of the ligand-binding domains (LBDs) of the EcR/USP heterodimer, complexed to the ecdysteroid ponasterone A (ponA) and to the lepidopteran specific bisacylhydrazine BYI06830 used in the agrochemical pest control, provide the first insight at atomic level for these important functional complexes [11].
• Both wild type and T187A mutant protein induced by 5 microM ponasterone A inhibited cell growth and increased cell number at the G1 phase [12].
• Stereoselective synthesis of (22R)- and (22S)-castasterone/ponasterone A hybrid compounds and evaluation of their molting hormone activity [13].
• After incubation of intact Kc cells, 200-300 specific binding sites were detected for both 20-OH ecdysone and ponasterone A [14].

Anatomical context of Ponasterone A

• We determined that reporter gene activity was induced by ponasterone A in myotubes, a differentiated muscle phenotype, but not in myoblasts (undifferentiated cells) [15].
• Brains and subesophageal ganglia from day 3.5 fifth stadium larvae of Manduca sexta were incubated in vitro with 4 nM tritiated ponasterone A, a 20-hydroxyecdysone analog, to determine whether uptake and specific binding of ecdysteroids occur at a cellular level [16].
• In fat body, even after an incubation of 60 min at 22 degrees C, the majority of specifically bound ponasterone A was located in the cytoplasm [14].
• Consistent with the presence of these enzymes in peripheral tissues, ecdysteroid products identified in the hemolymph were 20E, 3D20E, and 25-deoxy-20-hydroxyecdysone (25d20E; ponasterone A) [17].
• In gastrolith epithelium, ponasterone A binding sites first appeared in the cytoplasm, and then in the nuclei and cytoplasm [18].

Associations of Ponasterone A with other chemical compounds

• The concomitant production of these 2 molecules by Y-organs and their subsequent hydroxylation at C-20 by peripheral tissues, provide an explanation for the presence of both 20-hydroxyecdysone and ponasterone A (25-deoxy-20-hydroxyecdysone) in the circulating haemolymph of crabs [19].
• Two stereoisomers of a castasterone/ponasterone A hybrid compound, the (20R,22R) and (20R,22S)-isomers of 2alpha,3alpha,20,22-tetrahydroxy-5alpha-cholestan-6-one, were synthesized stereoselectively and their binding activity to the ecdysteroid receptor was determined [13].
• The simultaneous determination of four test ecdysteroids, 20-hydroxyecdysone, ajugasterone C, polypodine B and ponasterone A has been investigated by using the normal stacking mode in MEKC with UV detection [20].
• The ecdysone inducible gene expression system: unexpected effects of muristerone A and ponasterone A on cytokine signaling in mammalian cells [21].
• Here we report the crystal structures of the ligand-binding domains of the moth Heliothis virescens EcR-USP heterodimer in complex with the ecdysteroid ponasterone A and with a non-steroidal, lepidopteran-specific agonist BYI06830 used in agrochemical pest control [22].

Gene context of Ponasterone A

• Treatment of cells with the synthetic ecdysone analog ponasterone A induced expression of GFP-MKK7(3E) and resulted in sustained activation of endogenous JNK, but neither of the other endogenous MAPKs, ERK or p38 [23].
• Expression of both ABCA1 and ABCA7 was induced linearly proportional to ponasterone A concentration in the medium [24].
• Induction of cyclin D1 antisense mRNA by the ecdysteroid, ponasterone A, resulted in a 55% decrease in cyclin D1 mRNA and a 58% decrease in CD1 protein levels [25].
• The BACE1 protein level was increased in a time- and dosage-dependent manner in the inducible BACE1 stable cells by treatment with inducer ponasterone A [26].
• USP and EcR fusion proteins could be expressed in separate cell lines and then recombined following isolation to yield a ligand binding preparation with a dissociation constant (K(D)) for Ponasterone A of 1.5 nM and a total yield of 1.9 pmol ligand binding sites/mg protein [27].

Analytical, diagnostic and therapeutic context of Ponasterone A

• RESULTS: After treatment with ponasterone A, we could find an induction of both p27(Kip1) wild type and T187A mutant protein [12].
• Using cDNA arrays and quantitative PCR, we discovered nine genes whose expression was increased, but no genes whose expression was reduced, following 24 h of induction with Ponasterone A (PonA), a ligand for EcR [28].
• However, other minor compounds have been detected (some unknown, others migrating like ecdysone and ponasterone A in HPLC) [29].
• Following the onset of feeding, there appeared both specific ponasterone A binding and two major EcR bands detected by Western blot analysis [30].
• DU145 cell cultures in complete medium exhibited a maximum of approximately 28% of apoptotic cells after 96 h of exposure to an ecdysone analog, Ponasterone A [31].

References