Rap1A (IC50 = 3 μM, in vivo), Ha-Ras (IC50 > 20 μM, in vivo)[3]

The apical K+ conductance increased by cAMP agonist is considerably reduced by RhoA inhibitor (GGTI298 Trifluoroacetate)[1]. When GGTI298 Trifluoroacetate and TRAIL are used to cause DR5-dependent apoptosis, DR4 knockdown eliminates NF-κB activation and makes the cell more susceptible to this process. Trifluoroacetate/TRAIL (GGTI298 ) inhibits Akt and increases NF-κB. IκBα and p-Akt reduction produced by GGTI298/TRAIL are prevented by DR5 knockdown, indicating that DR5 mediates the reduction of these molecules induced by GGTI298/TRAIL. On the other hand, DR4 knockdown makes GGTI298 /TRAIL-induced p-Akt decrease even easier[2].

In vivo mouse ileal loop experiments demonstrate that injections of TRAM-34, GGTI298 Trifluoroacetate, or H1152 in conjunction with cholera toxin reduce fluid accumulation in a dose-dependent manner[1].

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 A major barrier towards the study of the effects of drugs on Giant Cell Tumor of Bone (GCT) has been the lack of an animal model. In this study, we created an animal model in which GCT stromal cells survived and functioned as proliferating neoplastic cells. A proliferative cell line of GCT stromal cells was used to create a stable and luciferase-transduced cell line, Luc-G33. The cell line was characterized and was found that there were no significant differences on cell proliferation rate and recruitment of monocytes when compared with the wild type GCT stromal cells. We delivered the Luc-G33 cells either subcutaneously on the back or to the tibiae of the nude mice. The presence of viable Luc-G33 cells was assessed using real-time live imaging by the IVIS 200 bioluminescent imaging (BLI) system. The tumor cells initially propagated and remained viable on site for 7 weeks in the subcutaneous tumor model. We also tested in vivo antitumor effects of Zoledronate (ZOL) and Geranylgeranyl transferase-I inhibitor (GGTI-298) alone or their combinations in Luc-G33-transplanted nude mice. ZOL alone at 400 µg/kg and the co-treatment of ZOL at 400 µg/kg and GGTI-298 at 1.16 mg/kg reduced tumor cell viability in the model. Furthermore, the anti-tumor effects by ZOL, GGTI-298 and the co-treatment in subcutaneous tumor model were also confirmed by immunohistochemical (IHC) staining. In conclusion, we established a nude mice model of GCT stromal cells which allows non-invasive, real-time assessments of tumor development and testing the in vivo effects of different adjuvants for treating GCT.[4]

Researchers have used specific inhibitors for farnesyltransferase (FTase) and geranylgeranyltransferase (GGTase) I as well as combinations of lovastatin with geranylgeraniol (GGOH) or farnesol (FOH) to investigate the role of protein prenylation in platelet-derived growth factor (PDGF)-induced PDGF receptor tyrosine phosphorylation. NIH-3T3 cells treated with the highly specific FTase inhibitor FTI-277 had no effect on PDGF receptor tyrosine phosphorylation or PDGF activation of mitogen-activated protein kinase (MAPK) at doses that completely inhibit FTase-dependent processing. In contrast, treatment of these cells with GGTase I inhibitor GGTI-298 strongly inhibited receptor tyrosine phosphorylation, and co-treatment with FTI-277 had no additional effect. Interestingly, the inhibitory effect of GGTI-298 on PDGF activation of MAPK was only partial. Furthermore, although lovastatin, which inhibits both protein geranylgeranylation and protein farnesylation, blocked PDGF receptor tyrosine phosphorylation, co-treatment with GGOH, but not FOH, reversed the lovastatin block. In addition, although lovastatin was observed to block MAPK activation by PDGF, co-treatment with GGOH, but not FOH, restored its activation. Further investigations indicated that inhibition of receptor tyrosine phosphorylation was not due to decreased expression of the receptor or to inhibition of GGTase II. Thus, these results demonstrate that PDGF receptor tyrosine phosphorylation requires protein geranylgeranylation but not protein farnesylation and that the tyrosine phosphorylation levels of the receptor are modulated by a protein that is a substrate for GGTase I.[3]

Cell Survival Assay[2]
Cells were seeded in 96-well cell culture plates and treated the next day with the agents indicated. The viable cell number was determined using the sulforhodamine B assay, as previously described.

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Detection of Apoptosis[2]
Apoptosis was evaluated by Annexin V staining using Annexin V-PE apoptosis detection kit purchased commercially following the manufacturer's instructions. Caspase activation was also detected by Western blotting (as described below) as an additional indicator of apoptosis.

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Western Blot Analysis[2]
Whole-cell protein lysates were prepared and analyzed by Western blotting as described previously

Mouse Ileal Loop Experiment[1]
The ileal loop experiment was performed in 6–8-week-old mice by a modified rabbit ileal loop assay originally described by De and Chatterje. Following gut sterilization, the animals were kept fasted for 24 h prior to surgery and fed only water ad libitum. Anesthesia was induced by a mixture of ketamine (35 mg/kg of body weight) and xylazine (5 mg/kg of body weight). A laparotomy was performed, and the experimental loops of 5-cm length were constricted at the terminal ileum by tying with non-absorbable silk. The following fluids were instilled in each loop by means of a tuberculin syringe fitted with a disposable needle through the ligated end of the loop as the ligatured was tightened: pure CT (1 μg; positive control), saline (negative control), CT (1 μg) + TRAM-34 (different concentrations in μm as indicated in Fig. 7), CT (1 μg) + H1152 (1 μm), and CT (1 μg) + GGTI298 (different concentrations in μm), a specific inhibitor of Rap1A. The intestine was returned to the peritoneum, and the mice were sutured and returned to their cages. After 6 h, these animals were sacrificed by cervical dislocation, and the loops were excised. The fluid from each loop was collected, and the ratio of the amount of fluid contained in the loop with respect to the length of the loop (fluid accumulation ratio in g/cm) was calculated as a reflection of the efficacy of various inhibitors.

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dissolved in DMSO, dilute in saline; 1.16 mg/kg; s.c. injection

Nude mice

[1]. The Epac1 signaling pathway regulates Cl- secretion via modulation of apical KCNN4c channels in diarrhea. J Biol Chem. 2013 Jul 12;288(28):20404-15.

[2]. Dissecting the roles of DR4, DR5 and c-FLIP in the regulation of geranylgeranyltransferase I inhibition-mediated augmentation of TRAIL-induced apoptosis. Mol Cancer. 2010 Jan 29;9:23.

[3]. Platelet-derived growth factor receptor tyrosine phosphorylation requires protein geranylgeranylation but not farnesylation. J Biol Chem. 1996 Nov 1;271(44):27402-7.

[4]. A mouse model of luciferase-transfected stromal cells of giant cell tumor of bone. Connect Tissue Res. 2015 Nov;56(6):493-503.

The apical membrane of intestinal epithelia expresses intermediate conductance K(+) channel (KCNN4), which provides the driving force for Cl(-) secretion. However, its role in diarrhea and regulation by Epac1 is unknown. Previously we have established that Epac1 upon binding of cAMP activates a PKA-independent mechanism of Cl(-) secretion via stimulation of Rap2-phospholipase Cε-[Ca(2+)]i signaling. Here we report that Epac1 regulates surface expression of KCNN4c channel through its downstream Rap1A-RhoA-Rho-associated kinase (ROCK) signaling pathway for sustained Cl(-) secretion. Depletion of Epac1 protein and apical addition of TRAM-34, a specific KCNN4 inhibitor, significantly abolished cAMP-stimulated Cl(-) secretion and apical K(+) conductance (IK(ap)) in T84WT cells. The current-voltage relationship of basolaterally permeabilized monolayers treated with Epac1 agonist 8-(4-chlorophenylthio)-2'-O- methyladenosine 3',5'-cyclic monophosphate showed the presence of an inwardly rectifying and TRAM-34-sensitive K(+) channel in T84WT cells that was absent in Epac1KDT84 cells. Reconstructed confocal images in Epac1KDT84 cells revealed redistribution of KCNN4c proteins into subapical intracellular compartment, and a biotinylation assay showed ∼83% lower surface expression of KCNN4c proteins compared with T84WT cells. Further investigation revealed that an Epac1 agonist activates Rap1 to facilitate IK(ap). Both RhoA inhibitor (GGTI298) and ROCK inhibitor (H1152) significantly reduced cAMP agonist-stimulated IK(ap), whereas the latter additionally reduced colocalization of KCNN4c with the apical membrane marker wheat germ agglutinin in T84WT cells. In vivo mouse ileal loop experiments showed reduced fluid accumulation by TRAM-34, GGTI298, or H1152 when injected together with cholera toxin into the loop. We conclude that Rap1A-dependent signaling of Epac1 involving RhoA-ROCK is an important regulator of intestinal fluid transport via modulation of apical KCNN4c channels, a finding with potential therapeutic value in diarrheal diseases.[1]

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Background: Geranylgeranyltransferase I (GGTase I) has emerged as a cancer therapeutic target. Accordingly, small molecules that inhibit GGTase I have been developed and exhibit encouraging anticancer activity in preclinical studies. However, their underlying anticancer mechanisms remain unclear. Here we have demonstrated a novel mechanism by which GGTase I inhibition modulates apoptosis.
Results: The GGTase I inhibitor GGTI-298 induced apoptosis and augmented tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human lung cancer cells. GGTI-298 induced DR4 and DR5 expression and reduced c-FLIP levels. Enforced c-FLIP expression or DR5 knockdown attenuated apoptosis induced by GGTI-298 and TRAIL combination. Surprisingly, DR4 knockdown sensitized cancer cells to GGTI298/TRAIL-induced apoptosis. The combination of GGTI-298 and TRAIL was more effective than each single agent in decreasing the levels of IkappaBalpha and p-Akt, implying that GGTI298/TRAIL activates NF-kappaB and inhibits Akt. Interestingly, knockdown of DR5, but not DR4, prevented GGTI298/TRAIL-induced IkappaBalpha and p-Akt reduction, suggesting that DR5 mediates reduction of IkappaBalpha and p-Akt induced by GGTI298/TRAIL. In contrast, DR4 knockdown further facilitated GGTI298/TRAIL-induced p-Akt reduction.
Conclusions: Both DR5 induction and c-FLIP downregulation contribute to GGTI-298-mediated augmentation of TRAIL-induced apoptosis. Moreover, DR4 appears to play an opposite role to DR5 in regulation of GGTI/TRAIL-induced apoptotic signaling.[2]

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C27H33N3O3S.C2HF3O2

593.66

593.217

C, 58.67; H, 5.77; F, 9.60; N, 7.08; O, 13.47; S, 5.40

1217457-86-7

GGTI298;180977-44-0; GGTI298 Trifluoroacetate; 1217457-86-7; 205590-41-6 (HCl)

16078971

White to off-white solid powder

6.474

5

11

11

41

745

2

CC(C)C[C@@H](C(OC)=O)NC(C1=CC=C(NC[C@@H](N)CS)C=C1C2=C3C=CC=CC3=CC=C2)=O.O=C(O)C(F)(F)F

WALKWJPZELDSKT-UFABNHQSSA-N

InChI=1S/C27H33N3O3S.C2HF3O2/c1-17(2)13-25(27(32)33-3)30-26(31)23-12-11-20(29-15-19(28)16-34)14-24(23)22-10-6-8-18-7-4-5-9-21(18)22;3-2(4,5)1(6)7/h4-12,14,17,19,25,29,34H,13,15-16,28H2,1-3H3,(H,30,31);(H,6,7)/t19-,25+;/m1./s1

methyl (2S)-2-[[4-[[(2R)-2-amino-3-sulfanylpropyl]amino]-2-naphthalen-1-ylbenzoyl]amino]-4-methylpentanoate;2,2,2-trifluoroacetic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: 2.5 mg/mL (4.21 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 2.5 mg/mL (4.21 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (4.21 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)