Suppression of macrophages- Induced inflammation via targeting RAS and PAR-4 signaling in breast cancer cell lines.

Tumor associated macrophages (TAMs) have a crucial role in cancer progression, metastasis and drug response. Piroxicam and sulindac sulfide are non-steroidal anti-inflammatory drugs (NSAID) that decrease the incidence and progression of several types of cancer. However, their role in suppressing the interactions between TAMs and cancer cells remain unclear. Herein, we studied the impact of human monocytes conditioned media (CM) on cellular proliferation of ER-dependent MCF-7 and ER-independent MDA-MB-231 cells, and the effects of piroxicam and sulindac sulfide on the expression levels of RAS, COX-2, IL-6, IL-1ß and PAR-4 (qRT-PCR), BCL-2 and BAX (western blot), Caspase-3, VEGF-a and PGE2 (ELISA), MMP-2 and -9 (zymography) in the stimulated cells. Our results showed that CM caused a significant increase in cells survival through significant increase in RAS expression which resulted in upregulation of COX-2, PGE2, BCL-2, IL-6, IL-1ß, VEGF-A and MMP-9 and down regulation of PAR-4. Treatment with one of the NSAIDs used in this study produced a time and concentration dependent growth inhibition of stimulated cells by inhibiting RAS expression. Suppression of RAS was accompanied by downregulation of its downstream signaling of IL-1ß, IL-6, COX-2 and PGE2, activation of apoptotic machinery through upregulation of PAR-4 and caspase-3, as well as, inhibition of BCL-2, VEGF-A, MMP-2 and MMP-9. In conclusion, our data support the role of piroxicam and sulindac sulfide in suppressing inflammation-driven breast cancer progression and identifies promising novel target in RAS and PAR-4 signaling.

Combining Bevacizumab with Knocked-Down ß-Catenin Reduces VEGF-A and Slug mRNA in HepG2 but not in Caco-2 Cell Lines.

BACKGROUND: Bevacizumab (Bev) resistance is hypothesized to be overcome by combining inhibitors of other signalling pathways. OBJECTIVE: We aimed to study the effect of combining Bev with knocked down ß-catenin (Bev-ß-cat-siRNA) on the expression of VEGF-A, Slug, NFκB, and its two target genes, c-Flip and FasR, in HepG2. Expression of VEGF-A and Slug was also studied in Caco-2 cells. METHODS: Cultured cells were divided into six groups 1) cells treated with Bev, 2) cells treated with ß-catenin-siRNA, 3) cells treated with Bev-ß-cat-siRNA, 4) cells treated with negative control, 5) cells treated with Bev-negative control, and 6) untreated cells. Expressions were assessed using qPCR and western blotting. RESULTS: Bev-ß-cat-siRNA significantly reduced the mRNA level of VEGF-A, which was initially increased in response to Bev alone in HepG2 but not in Caco-2. Additionally, Bev-ß-cat-siRNA significantly decreased Slug mRNA level compared to Bev treated HepG2 cells. In contrast, VEGF-A and Slug mRNA levels in Bev group were remarkably lower than Bev-ß-cat-siRNA in Caco-2 cells. Distinct ß-catenin and Slug protein expressions were noticed in HepG2 and Caco-2 cells. On the other hand, Bev-ß-catsiRNA remarkably reduced the level of NFκB, FasR, and c-Flip compared to Bev treated HepG2 cells, although the difference was not statistically significant. CONCLUSION: We conclude that combining Bevacizumab with knocked down ß-catenin reduces the expression of VEGF-A and Slug in HepG2 but not in Caco-2 cells.

Possible Use of miR-223-3p as a Prognostic Marker in Transarterial Chemoembolization Treatment of Hepatocellular Carcinoma Patients.

INTRODUCTION AND OBJECTIVES: Transcatheter chemoembolization (TACE) is the recommended therapy for intermediate stage hepatocellular carcinoma patients. Unfortunately, one of the main reasons for its failure is the emergence of multidrug resistance (MDR). Therefore, this study explored the possibility of using MDR-related miRNA as a response biomarker in HCC patients treated with doxorubicin drug-eluting bead TACE (DEB-TACE). PATIENTS AND METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to evaluate the expression level of 14 MDR-related miRNAs in doxorubicin-resistant HepG2 cells (HepG2/Dox) developed by single-dose of doxorubicin mimicking the situation of liver cells surviving TACE. The sera level of miR-223-3p, which was the most significantly downregulated in the HepG2 cells, was determined in 60 primary HCC patients undergoing TACE. Restoring miR-223-3p in HepG2/Dox cell line was achieved by its mimic transfection. Cell sensitivity was measured by SRB assay. Cell apoptosis and doxorubicin uptake were assessed by flow cytometry. The expression of miR-223-3p target protein, P-glycoprotein, was evaluated using qRT-PCR and western blotting. RESULTS: We detected a significant downregulation of circulating miR-223-3p in patients non-responders to TACE treatment compared with responders. The expression of miR-223-3p was markedly decreased in resistant HepG2/Dox cells compared to the parental control. In addition, the expression of miR-223-3p was found to be inversely correlated with P-glycoprotein expression thus confirming the role of miR-223-3p in MDR. Furthermore, overexpression of miR-223-3p suppressed P-glycoprotein which promoted cellular uptake of doxorubicin and increased apoptosis. CONCLUSIONS: Our data suggest a potential role for miR-233-3p as a prognostic as well as a therapeutic target for HCC.

Infection with Toxoplasma gondii results in dysregulation of the host cell cycle.

Mammalian cells infected with Toxoplasma gondii are characterized by a profound reprogramming of gene expression. We examined whether such transcriptional responses were linked to changes in the cell cycle of the host. Human foreskin fibroblasts (HFFs) in the G(0)/G(1) phase of the cell cycle were infected with T. gondii and FACS analysis of DNA content was performed. Cell cycle profiles revealed a promotion into the S phase followed by an arrest towards the G(2)/M boundary with infection. This response was markedly different from that of growth factor stimulation which caused cell cycle entry and completion. Transcriptional profiles of T. gondii-infected HFF showed sustained increases in transcripts associated with a G(1)/S transition and DNA synthesis coupled to an abrogation of cell cycle regulators critical in G(2)/M transition relative to growth factor stimulation. These divergent responses correlated with a distinct temporal modulation of the critical cell cycle regulator kinase ERK by infection. While the kinetics of ERK phosphorylation by EGF showed rapid and sustained activation, infected cells displayed an oscillatory pattern of activation. Our results suggest that T. gondii infection induces and maintains a 'proliferation response' in the infected cell which may fulfill critical growth requirements of the parasite during intracellular residence.

Novel CYP1B1 mutations and a possible prognostic use for surgical management of congenital glaucoma.

AIM: To identify CYP1B1 gene mutations and evaluate their possible role as a prognostic factor for success rates in the surgical management of Egyptian congenital glaucoma patients. METHODS: Totally 42 eyes of 29 primary congenital glaucoma patients were operated on with combined trabeculotomy/trabeculectomy with mitomycin-C and followed up at 1d, 1wk, 1, 6 and 12mo postoperatively. Genomic DNA was extracted from peripheral blood leukocytes. Coding regions of CYP1B1 gene were amplified using 13 pairs of primers, screened for mutations using single-strand conformation polymorphism followed by sequencing of both strands. Efficacy of the operation was graded as either a success [maintaining intraocular pressure (IOP) less than 21 mm Hg with or without anti-glaucoma medication], or a failure (IOP more than 21 mm Hg with topical antiglaucoma medications). RESULTS: Seven novel mutations out of a total of 15 different mutations were found in the CYP1B1 genes of 14 patients (48.2%). The presence of CYP1B1 gene mutations did not correlate with the failure of the surgery (P=0.156, odds ratio=3.611, 95%CI, 0.56 to 22.89); while the positive consanguinity strongly correlated with failure of the initial procedure (P=0.016, odds ratio=11.25, 95%CI, 1.57 to 80.30). However, the Kaplan-Meier survival analysis revealed a significantly lower time of IOP control in the subgroup with mutations in CYP1B1 versus the congenital primary glaucoma group without mutations (log rank test, P=0.015). CONCLUSION: Seven new CYP1B1 mutations are identified in Egyptian patients. Patients harboring confirmed mutations suffered from early failure of the initial surgery. CYP1B1 mutations could be considered as a prognostic factor for surgery in primary congenital glaucoma.

Identification of a unique core domain of par-4 sufficient for selective apoptosis induction in cancer cells.

Recent studies indicated that the leucine zipper domain protein Par-4 induces apoptosis in certain cancer cells by activation of the Fas prodeath pathway and coparallel inhibition of NF-kappaB transcriptional activity. However, the intracellular localization or functional domains of Par-4 involved in apoptosis remained unknown. In the present study, structure-function analysis indicated that inhibition of NF-kappaB activity and apoptosis is dependent on Par-4 translocation to the nucleus via a bipartite nuclear localization sequence, NLS2. Cancer cells that were resistant to Par-4-induced apoptosis retained Par-4 in the cytoplasm. Interestingly, a 59-amino-acid core that included NLS2 but not the C-terminal leucine zipper domain was necessary and sufficient to induce Fas pathway activation, inhibition of NF-kappaB activity, and apoptosis. Most important, this core domain had an expanded target range for induction of apoptosis, extending to previously resistant cancer cells but not to normal cells. These findings have identified a unique death-inducing domain selective for apoptosis induction in cancer cells (SAC domain) which holds promise for identifying key differences between cancer and normal cells and for molecular therapy of cancer.

The Liver MicroRNA Expression Profiles Associated With Chronic Hepatitis C Virus (HCV) Genotype-4 Infection: A Preliminary Study.

BACKGROUND: MicroRNAs (miRNAs) have been repeatedly shown to play important roles in liver pathologies, including hepatitis, liver cirrhosis, and liver cancer. Egypt has the highest hepatitis C virus (HCV) infection rate worldwide, predominantly involving genotype-4. OBJECTIVES: In this study, we attempted to characterize the miRNA profile of the poorly studied genotype 4 of HCV in chronically infected Egyptian patients to obtain a better understanding of the disease and its complications and help in the design of better management protocols. PATIENTS AND METHODS: We analyzed the expression levels of a selected panel of 94 miRNAs in fresh liver biopsies collected from 50 Egyptian patients diagnosed with chronic HCV infection using quantitative real-time polymerase chain reaction (PCR) assay. Non-parametric tests were used to analyze the expression level of each miRNA and association with the clinicopathological features of enrolled patients in this study. RESULTS: Our results revealed differential expression levels of the analyzed miRNAs compared to the normal controls. Twenty-seven miRNAs (including miR-105, miR-147, miR-149-3p, and miR-196b) showed up-regulation, while 17 miRNAs (including miR-21, miR-122, miR-199a-3p, and miR-223) showed down-regulation. An inverse correlation was observed between levels of miR-95, miR-130a, and miR-142-5p with the blood albumin level. Increased expression levels of seven miRNAs (miR-29c, miR-30c, miR-126, miR-145, miR-199a, miR-199a-3p, and miR-222) were observed with severe chronic hepatic inflammation. Several deregulated miRNAs found in this study have been previously linked to chronic liver inflammation and the risk of hepatocellular carcinoma (HCC) development. CONCLUSIONS: The identified expression profiles of some examined miRNAs might offer important points to consider for the treatment of naive patients and the management of chronically infected HCV patients in Egypt and around the world.

Mutational hotspots in the mitochondrial D-loop region of cancerous and precancerous colorectal lesions in Egyptian patients.

Mutations in the mitochondrial genome (mtDNA) are associated with different types of cancer, specifically colorectal cancer (CRC). However, few studies have been performed on precancerous lesions, such as ulcerative colitis (UC) lesions and adenomatous polyps (AP). The aim of this study was to identify mtDNA mutations in the cancerous and precancerous lesions of Egyptian patients. An analysis of the mutations found in six regions of the mtDNA genome (ND1, ND5, COI, tRNAser, D-loop 1, and 2) in 80 Egyptian patients (40 CRC, 20 UC, and 20 AP) was performed using polymerase chain reaction-single-strand conformational polymorphism techniques and followed up by direct sequencing. The overall incidence of mutations was 25%, 25%, and 35% in CRC, UC, and AP cases, respectively. Although there was no common mutation pattern within each group, a large number of mutations were detected in the D-loop region in all of the groups. Some mutations (e.g., T414G) were detected repeatedly in precancerous (UC and AP) and cancerous lesions. Mutations detected in patients with CRC were predominantly found in the ND1 gene (40%). Our preliminary study suggests that Egyptian patients with CRC have a large number of mtDNA mutations, especially in the D-loop region, which have not been previously reported. Mutations in the mtDNA of precancerous lesions (i.e., AP and UC) may contribute to transformation events that lead to CRC.

Potential problems inherent in cell-based stable NF-kappaB-GFP reporter systems.

The nuclear factor-kappaB (NF-kappaB) family of transcription factors plays a central role in numerous physiological processes including development, cell survival, immunity, and inflammation. We generated a series of stable clonal lines in mouse embryonic fibroblasts carrying NF-kappaB-GFP plasmid as a reporter. These cell lines were selected by flow cytometry for their high responsiveness to tumor necrosis factor (TNFalpha) or lipopolysaccharide (LPS), two classic NF-kappaB-inducing stimuli. Although all clones were generated from the same parental cell line, they each had a distinctive pattern of response to NF-kappaB stimuli. While exhibiting distinct profiles with regard to the GFP reporter, analysis of endogenous NF-kappaB downstream targets did not always show the same variability. This suggests that in the absence of confirmation of the signaling outcomes using endogenous outputs, considerable caution must be exercised in the interpretation of data using stable reporter systems.

Apoptosis by Par-4 in cancer and neurodegenerative diseases.

Prostate apoptosis response-4 (par-4) is a pro-apoptotic gene identified in prostate cancer cells undergoing apoptosis. Par-4 protein, which contains a leucine zipper domain at the carboxy-terminus, functions as a transcriptional repressor in the nucleus. Par-4 selectively induces apoptosis in androgen-independent prostate cancer cells and Ras-transformed cells but not in androgen-dependent prostate cancer cells or normal cells. Cells that are resistant to apoptosis by Par-4 alone, however, are greatly sensitized by Par-4 to the action of other pro-apoptotic insults such as growth factor withdrawal, tumor necrosis factor, ionizing radiation, intracellular calcium elevation, or those involved in neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and stroke. Apoptosis induction by Par-4 involves a complex mechanism that requires activation of the Fas death receptor signaling pathway and coparallel inhibition of cell survival NF-kappaB transcription activity. The unique ability of Par-4 to induce apoptosis in cancer cells but not normal cells and the ability of Par-4 antisense or dominant-negative mutant to abrogate apoptosis in neurodegenerative disease paradigms makes it an appealing candidate for molecular therapy of cancer and neuronal diseases.