Is phenytoin a safe agent for staple line recovery after gastric sleeve surgery in rats?

BACKGROUND: The most challenging and mortal complication of gastric sleeve surgery (SG) is staple line leakage. Although many agents have been used for increasing tissue healing on the stapler line, there is still no consensus on its effectiveness and efficacy. The aim of study is to determine the effect of phenytoin on the healing process of gastric sleeve surgery in rats. METHODS: On the 10th post-operative day, the effects of phenytoin on bursting pressure in the stapler line were evaluated along-side pathohistological examinations. To investigate the molecular impact of phenytoin on the expression of TGF-ß, VEGF, FGF2, and p53 genes, quantitative real-time polymerase chain reaction was utilized. In addition, gene expressions at the protein level were deter-mined by immunohistochemical analysis. RESULTS: No signs of intra-abdominal leakage were observed in the resected samples. A statistically essential extend in stable line bursting pressure measure was observed between the control group and the group treated with phenytoin application. Pathohisto-logical results indicate that the mean score of collagens of the study group (3.2±0.42) was significantly higher than the control group (2.3±0.48) (P=0.003). In addition, the mean epithelization score of the study group (3.4±0.52) was significantly higher than the control group (2.1±0.57) (P=0.001). mRNA of TGFß, FGF2, VEGF, and p53 genes drastically increased phenytoin treated group. High FGF2 protein expression levels were determined from phenytoin use compared to the control group. CONCLUSION: Molecular studies suggest that phenytoin may increase the healing process of Gastric sleeve following SG in rats and may become a new agent for the prevention of human gastric leaks.

Investigation of the effects of post-operative intraperitoneal, oral, and rectal phenytoin administration on colorectal anastomosis in rats.

BACKGROUND: Anastomotic leakage is the most feared complication after colonic anastomosis. The purpose of the study is to determine the effects of phenytoin applied by different application routes, on the healing process of colorectal anastomoses. METHODS: Wistar Albino rats were divided into Intraperitoneal Phenytoin Group, Oral Phenytoin Group (OAP), Rectal Phenytoin Group (RAP), and control groups. The molecular effect of phenytoin on the expression of vascular endothelial growth factor (VEGF), transforming growth factor-beta (TGF-ß), fibroblast growth factor 2 (FGF2), and p53 genes was evaluated at mRNA and protein level. The effects of phenytoin on anastomotic bursting pressure analysis measured as well as pathohistological examinations. RESULTS: There are statistically significant increase in anastomotic bursting pressure values between control and application groups. Inflammatory cell infiltration of all groups increased in the intestinal anastomosis region compared to control. Collagen scores were found to be significantly higher in the OAP and RAP groups compared to the control group. mRNA of TGF-ß and FGF2 expression increased in all routes of phenytoin applications. CONCLUSION: Three different administration routes show considerably increase on the bursting pressure. Regarding the results of the expression of FGF2, TGF-ß, p53, and VEGF genes, there is a significant increase FGF2 and TGF-ß at mRNA and protein level in most administration routes.

Strigolactone Analogs: Two New Potential Bioactiphores for Glioblastoma.

Strigolactones (SLs), carotenoid-derived phytohormones, control the plant response and signaling pathways for stressful conditions. In addition, they impact numerous cellular processes in mammalians and present new scaffolds for various biomedical applications. Recent studies demonstrated that SLs possess potent antitumor activity against several cancer cells. Herein, we sought to elucidate the inhibitory effects of SL analogs on the growth and survival of human brain tumor cell lines. Among four tested SLs, we showed for the first time that two lead bioactiphores, indanone-derived SL and EGO10, can inhibit cancer cell proliferation, induce apoptosis, and induce G1 cell cycle arrest at low concentrations. SL analogs were marked by increased expression of Bax/Caspase-3 genes and downregulation of Bcl-2. In silico studies were conducted to identify drug-likeness, blood-brain barrier penetrating properties, and molecular docking with Bcl-2 protein. Taken together, this study indicates that SLs may be promising antiglioma agents, presenting novel pharmacophores for further preclinical and clinical assessment.

TNF-α Induces URG-4/URGCP Gene Expression in Hepatoma Cells through Starvation Dependent Manner.

URG-4/URGCP is a gene that may be associated with the onset of tumorigenesis and cell cycle regulation. In the literature, there is no study about inflammatory cytokine-mediated URG-4/URGCP regulation. In this study, the effect of TNF-α cytokine was investigated on URG-4/URGCP expression in serum-starved and serum-cultured hepatoma cells. The effect of TNF-α on hepatoma cells was shown using MTT and Annexin-V/PI staining with flow cytometer analyses. As a result, TNF-α leads to the cytotoxicity of hepatoma cells in serum-starved condition whereas no decrease was detected from serum-cultured condition. TNF-α-mediated URG-4/URGCP expression was determined at mRNA and protein level with qRT-PCR analyses and Western blotting method. URG-4URGCP mRNA expression was upregulated in both serum-starved and serum-cultured hepatoma cells. The transfection studies were carried out with URG-4/URGCP promoter constructs for determining the transcriptional activity. TNF-α caused to the upregulation of the activities of URG/URGCP promoter constructs. The basal activities of the URG-4/URGCP promoter conditions are differential according to serum conditions. In addition, some pathway inhibitors were added into hepatoma cells for blocking specific pathways to find out TNF-α-mediated URG-4/URGCP upregulation at mRNA and protein level. TNF-α used JNK and PI3K pathways for regulating URG-4/URGCP gene at serum-starved Hep3B cells. In serum-cultured condition, wortmannin (PI3K inhibitor), MEK-1 (MAPK inhibitor), and SP600125 (JNK inhibitor) did not inhibit the activation response of TNF-α on URGCP.

Prodrugs for nitroreductase based cancer therapy-4: Towards prostate cancer targeting: Synthesis of N-heterocyclic nitro prodrugs, Ssap-NtrB enzymatic activation and anticancer evaluation.

In this study, various N-heterocyclic nitro prodrugs (NHN1-16) containing pyrimidine, triazine and piperazine rings were designed and synthesized. The final compounds were identified using FT-IR, 1H NMR, 13C NMR as well as elemental analyses. Enzymatic activities of compounds were conducted by using HPLC analysis to investigate the interaction of substrates with Ssap-NtrB nitroreductase enzyme. MTT assay was performed to evaluate the toxic effect of compounds against Hep3B and PC3 cancer cell lines and healthy HUVEC cell. It was observed that synthesized compounds NHN1-16 exhibited different cytotoxic profiles. Pyrimidine derivative NHN3 and triazine derivative NHN5 can be good drug candidates for prostate cancer with IC50 values of 54.75 µM and 48.9 µM, respectively. Compounds NHN6, NHN10, NHN12, NHN14 and NHN16 were selected as prodrug candidates because of non-toxic properties against three different cell models. The NHN prodrugs and Ssap-NtrB combinations were applied to SRB assay to reveal the prodrug capabilities of these selected compounds. SRB screening results showed that the metabolites of all selected non-toxic compounds showed remarkable cytotoxicity with IC50 values in the range of 1.71-4.72 nM on prostate cancer. Among the tested compounds, especially piperazine derivatives NHN12 and NHN14 showed significant toxic effect with IC50 values of 1.75 nM and 1.79 nM against PC3 cell compared with standart prodrug CB1954 (IC50: 1.71 nM). Novel compounds NHN12 and NHN14 can be considered as promising prodrug candidates for nitroreductase-prodrug based prostate cancer therapy.

Prodrugs for nitroreductase-based cancer therapy-3: Antitumor activity of the novel dinitroaniline prodrugs/Ssap-NtrB enzyme suicide gene system: Synthesis, in vitro and in silico evaluation in prostate cancer.

Prodrugs for targeted tumor therapies have been extensively studied in recent years due to not only maximising therapeutic effects on tumor cells but also reducing or eliminating serious side effects on healthy cells. This strategy uses prodrugs which are safe for normal cells and form toxic metabolites (drugs) after selective reduction by enzymes in tumor tissues. In this study, prodrug candidates (1-36) containing nitro were designed, synthesized and characterized within the scope of chemical experiments. Drug-likeness properties of prodrug candidates were analyzed using DS 2018 to investigate undesired toxicity effects. In vitro cytotoxic effects of prodrug canditates were performed with MTT assay for human hepatoma cells (Hep3B) and prostate cancer cells (PC3) and human umbilical vein endothelial cells (HUVEC) as healthy control. Non-toxic compounds (3, 5, 7, 10, 12, 15, 17, 19 and 21-23), and also compounds (1, 2, 5, 6, 9, 11, 14, 16, 20 and 24) which had low toxic effects, were selected to examine their suitability as prodrug canditates. The reduction profiles and kinetic studies of prodrug/Ssap-NtrB combinations were performed with biochemical analyses. Then, selected prodrug/Ssap-NtrB combinations were applied to prostate cancer cells to determine toxicity. The results of theoretical, in vitro cytotoxic and biochemical studies suggest 14/Ssap-NtrB, 22/Ssap-NtrB and 24/Ssap-NtrB may be potential prodrug/enzyme combinations for nitroreductase (Ntr)-based prostate cancer therapy.

PRODRUGS FOR NITROREDUCTASE BASED CANCER THERAPY- 2: Novel amide/Ntr combinations targeting PC3 cancer cells.

The use of nitroreductases (NTR) that catalyze the reduction of nitro compounds by using NAD(P)H in GDEPT (Gene-directed enzyme prodrug therapy) studies which minimize toxicity at healthy cells and increases concentration of drugs at cancer cells is remarkable. Discovery of new prodrug/NTR combinations is necessary to be an alternative to known prodrug candidates such as CB1954, SN23862, PR-104A. For this aim, nitro containing aromatic amides (A1-A23)2 were designed, synthesized, performed in silico ADMET and molecular docking techniques in this study. Prodrug candidates were studied on reduction potentials with Ssap-NtrB by HPLC system. Also, cyototoxic properties and prodrug ability of these amides were investigated using different cancer cell lines such as Hep3B and PC3. As a result of theoretical and biological studies, combinations of A5, A6 and A20 with Ssap-NtrB can be suggested as potential prodrugs/enzyme combinations at NTR based cancer therapy compared with CB1954/NfsB.

Prodrugs for Nitroreductase Based Cancer Therapy- 1: Metabolite Profile, Cell Cytotoxicity and Molecular Modeling Interactions of Nitro Benzamides with Ssap-NtrB.

BACKGROUND: Directed Enzyme Prodrugs Therapy (DEPT) as an alternative method against conventional cancer treatments, in which the non-toxic prodrugs is converted to highly cytotoxic derivative, has attracted an ample attention in recent years for cancer therapy studies. OBJECTIVE: The metabolite profile, cell cytotoxicity and molecular modeling interactions of a series of nitro benzamides with Ssap-NtrB were investigated in this study. METHOD: A series of nitro-substituted benzamide prodrugs (1-4) were synthesized and firstly investigated their enzymatic reduction by Ssap-NtrB (S. saprophyticus Nitroreductase B) using HPLC analysis. Resulting metabolites were analyzed by LC-MS/MS. Molecular docking studies were performed with the aim of investigating the relationship between nitro benzamide structures (prodrugs 1-4) and Ssap-NtrB at the molecular level. Cell viability assay was conducted on two cancer cell lines, hepatoma (Hep3B) and colon (HT-29) cancer models and healthy cell model HUVEC. Upon reduction of benzamide prodrugs by Ssap-NtrB, the corresponding amine effectors were tested in a cell line panel comprising PC-3, Hep3B and HUVEC cells and were compared with the established NTR substrates, CB1954 (an aziridinyl dinitrobenzamide). RESULTS: Cell viability assay resulted in while prodrugs 1, 2 and 3 had no remarkable cytotoxic effects, prodrug 4 showed the differential effect, showing moderate cytotoxicity with Hep3B and HUVEC. The metabolites that obtained from the reduction of nitro benzamide prodrugs (1-4) by Ssap-NtrB, showed differential cytotoxic effects, with none toxic for HUVEC cells, moderate toxic for Hep3B cells, but highly toxic for PC3 cells. CONCLUSION: Amongst all metabolites of prodrugs after Ssap-NtrB reduction, N-(2,4- dinitrophenyl)-4-nitrobenzamide (3) was efficient and toxic in PC3 cells as comparable as CB1954. Kinetic parameters, molecular docking and HPLC results also confirm that prodrug 3 is better for Ssap-NtrB than 1, 2 and 4 or known cancer prodrugs of CB1954 and SN23862, demonstrating that prodrug 3 is an efficient candidate for NTR based cancer therapy.

SP1 is a transcriptional regulator of URG-4/URGCP gene in hepatocytes.

URG-4/URGCP gene was implicated as an oncogene that contributes hepatocarcinogenesis regulated by Hepatitis-B-virus-encoded X antigen. However, the mechanism of transcriptional regulation of this gene remains largely unknown. For this reason, we focused on the functional analyses of URG4/URGCP promoter site. First, 545 bp of URG-4/URGCP, -482/+63, and three different 5'-truncated constructs, -109/+63, -261/+63, -344/+63 were cloned by PCR-based approach into pMetLuc luciferase reporter vector. Transient transfection assay showed that, -109/+63 construct has the highest activity. The promoter of URG-4/URGCP gene contained a CpG island region spanning 400 bp from translation start site. Many SP1/GC boxes, named GC-1 to GC-10 are present in 545 bp of URG-4/URGCP promoter. Because of presence of multiple SP1/GC boxes, promoter constructs were transiently co-transfected with SP1 expression vector to determine the effect of SP1 on URG-4/URGCP promoter activity. Co-transfection analyses induced the basal activity of -268/+63, -344/+63 and -482/+63 constructs. EMSA analysis of GC-4, GC-5, GC-6 and GC-7 binding sites located in -128/-148 bases, showed two DNA-protein binding complexes. Competition assay and super-shifted complexes indicated these complexes are resulted from SP1 binding. Also, site-directed mutagenesis of potential SP1 binding sites diminished both DNA-protein complexes and SP1-mediated upregulation of URG-4 promoter activity. These findings are valuable for understanding transcriptional regulation of URG4/URGCP that has a pivotal role in cancer progression.

Identification of intracellular pathways through which TGF-ß1 upregulates URG-4/URGCP gene expression in hepatoma cells.

AIMS: Up-regulated gene 4 (URG-4/URGCP) was strongly expressed in Hepatitis B infected liver and correlated with HBxAG (Hepatitis B x Antigen) protein and found to promote hepatocellular cancer. Transforming growth factor (TGF-ß1) is a multifunctional protein that effects cell proliferation, growth inhibition, differentiation and other functions. However, the mechanism of URG-4/URGCP regulation by TGF-ß1 and its significance in cancer progression remains largely unknown. MAIN METHODS: The effect of TGF-ß1 on URG-4/URGCP gene was determined using REAL TIME PCR at mRNA level and Western blotting/immunofluorescence at protein level. Transient transfection assays were carried out to find out which site of promoter is upregulated by TGF-ß1. KEY FINDINGS: We report the upregulation of URG-4/URGCP gene expression by TGF-ß1 in hepatoma cells along with prostate cancer cells, PC3. Transient transfection assays showed that the -109 to +63 promoter region contained the minimal TGF-ß1 response elements. TGF-ß1 markedly stimulated the URG-4/URGCP mRNA and protein that was blocked by MEK1 [MAPK (Mitogen-Activated Protein Kinase)/ERK (extracellular signal-regulated kinase) kinase 1] inhibitor, PD98059 and PI3K inhibitor, wortmannin. SIGNIFICANCE: These studies show for the first time that TGF-ß1 upregulates the expression of URG-4/URGCP in human hepatocytes and identifies the signaling pathways underlying this response.