Inhibition of the Wnt/b-catenin pathway using PNU-74654 reduces tumor growth in in vitro and in vivo models of colorectal cancer

BACKGROUND

Colorectal-cancer (CRC) is amongst the most lethal-cancers, mainly due to its metastatic spread and drug chemoresistance. Hence there is a need for new approaches to either increase the efficacy of current therapy or introduce new therapies that have greater efficacy. There is increasing evidence that dysregulation of WNT-signaling-pathway plays an essential role in the development and prognosis of CRC. Here we have investigated the therapeutic potential of targeting the WNT/b-catenin pathway using a novel Wnt/b-catenin inhibitor, PNU-74654, in combination with 5-FU in CRC.

METHODS

The anti-proliferative-effect of PNU-74654 was evaluated in two-/three-dimensional cell models. The activity of agents on cell growth, migration, invasion, cell cycle and apoptosis was evaluated by MTT, wound healing assay, invasion, FACS, and annexin V staining, respectively. The oxidant/antioxidant levels were also assessed by determining the level of MDA, SOD, as well as using the DCFH-DA assay. We used a xenograft model of CRC to investigate PNU-74654 activity alone and in combination with 5-FU follow by histological staining and biochemical and gene expression analyses by RT-PCR and western blot.

RESULTS

PNU-74654 inhibited cell-growth and synergistically affected the anti-tumor properties of 5-FU via modulation of Cyclin D1 and survivin. This agent inhibited the migration/invasion of colorectal cancer cells via perturbation of E-cadherin. Furthermore, PNU-74654 inhibited the tumor growth, which was more pronounced using the PNU-74654 plus 5-FU combination via induction of reactive oxygen species, down-regulation of SOD and modulation of MCP-1, P53, TNF-α.

CONCLUSIONS

Our finding demonstrated that PNU-74654 can target Wnt-pathway, interfere with cell-proliferation, induced-cell death, reduced-migration and interact with 5-FU, supporting further investigations on this therapeutic-approach for colorectal cancer.

Pathogenic role of the SP/ NK1R system in GBM cells through inhibiting the thioredoxin system

OBJECTIVES

Glioblastoma multiforme (GBM), a highly aggressive Grade IV brain tumor, is a significant public health issue due to its poor prognosis and incurability. Neuropeptide substance P (SP) plays a critical role in GBM tumor growth and development via activation of neurokinin-1receptor (NK1R). Moreover, SP is a pro-oxidant factor contributing to oxidative stress in various cell types. However, the link between SP and oxidative stress in cancer cells is not fully investigated. Here, we aimed to identify the effects of SP and NK1R antagonist, aprepitant, on the redox status of GBM cells.

MATERIALS AND METHODS

Resazurin assay was employed to determine the effect of aprepitant on viability of U87 glioblastoma cells. 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay was employed to measure the levels of intracellular reactive oxygen species (ROS). A quantitative real-time polymerase chain reaction was applied to measure the expression of proteins of the thioredoxin system. Commercial kits (ZellBio GmbH) were also used to measure the enzymatic activity of these proteins.

RESULTS

We found that SP increased ROS level in U87 GBM cells, and aprepitant significantly reduced this effect. Furthermore, we found that SP could also affect the thioredoxin system, a central antioxidant enzyme defense system. SP reduced both expression and enzymatic activity of the thioredoxin system's proteins, Trx and thioredoxin reductase (TrxR) and these effects were significantly reduced by aprepitant.

CONCLUSION

Our results indicated that SP activation of NK1R represented a link between oxidative stress and GBM and highlighted the need for further validations in future studies.

Physicochemical Properties of analogs α-Aminophosphonates Drugs Determined via Molecular Dynamics Simulation

Objective: Cyclin-dependent kinases (CDKs, play important roles in cell cycle regulation. Since deregulation of cyclins and/or alteration or absence of inhibitors has been associated with many cancers, there is strong interest in CDKs inhibitors that could play an necessary role in the discovery of a new family of antitumor agents. Material and Methods: Molecular modeling is used to design new materials, which the correct prediction of physical properties of realistic systems is required. Gromacs is an tool to perform molecular dynamics simulations and energy minimization of bimolecular systems which commonly consists of several tens to thousands of amino acid residues. From the simulations the first 100 ps were regarded as equilibration, leaving 900 ps for analysis purposes. Results: Thermodynamic properties density, potential energy, temperature, and pressure are given. In this results tetramethyl ((1,4-phenylenebis (azanediyl)) bis ((4-chlorophenyl) methylene)) bis (phosphonate) was found to be the better selective known inhibitor for cyclin-dependent kinase2 because it shown lowest energy.Conclusion: The phosphoric acid moiety is considered to bind to the affected protein more actively than the corresponding carboxylic acid because of its di anionic character.

Evaluation of the serum prooxidant-antioxidant balance before and after vitamin D supplementation in adolescent Iranian girls

PURPOSE

Oxidative stress is caused by an imbalance between the antioxidant defenses and pro-oxidant production in favor of pro-oxidant production. Vitamin D has the potential for both pro- and anti-oxidative effects. The aim of this study was to assess the effect of high dose vitamin D supplementation on the prooxidant-antioxidant balance (PAB) in Iranian girls attending High School.

MATERIALS AND METHODS

A total of 464 girls aged 12-18 years were asked to take vitamin D capsules containing 50000IU vitamin D₃ once a week for a period of 9 weeks. All variables were determined at baseline and after 9 weeks of intervention. Fasting blood samples were taken from all subjects. The serum levels of 25OHD were measured using an electrochemiluminescence method. Serum PAB levels were determined using an ELISA reader at a wavelength of 450 nm.

RESULTS

Vitamin D supplementation was associated with an increase in serum PAB (P < 0.001) and a reduction in serum LDL-C (P < 0.001), total cholesterol (P < 0.001) and HDL-C (P < 0.01) serum levels in Iranian adolescent girls. The results obtained from the current study show that there were significant improvements in weight (P < 0.001), BMI (P < 0.001) and FBG (P = 0.02) in adolescent girls who had 50-74.9 nmol/L serum 25OHD levels compared to <50 nmol/L ones after the vitamin D supplementation. There was no significant association between the serum PAB and all biochemical factors (P > 0.05 for all variables).

CONCLUSIONS

The results showed that vitamin D supplementation has increased the PAB levels in teenage girls.

Competitive adsorption of proteins on hydrogel contact lenses

PURPOSE

To compare sequential and competitive adsorption of some proteins onto hydrogel contact lenses.

METHODS

New, never-worn, group IV soft contact lenses were incubated in freshly prepared solutions of lysozyme, alpha-lactalbumin, and ribonuclease at room temperature for 5 days with constant shaking, during which time their adsorbed protein was directly measured using UV absorbances at 280 nm. Adsorption isotherms were prepared. The lenses were rinsed with distilled water following a second protein treatment.

RESULTS

We found that the chemical composition of the lens and the charge of the previously adsorbed protein affected sequential and competitive adsorption of proteins on a contact lens surface.

CONCLUSIONS

Sequential adsorption occurs only if the second protein has a more favorable electrostatic interaction; sequential adsorption involves almost total displacement of the preadsorbed protein.