Purpose Patients with ulcerative colitis (UC) are at increased risk for colorectal cancer, although mechanisms underlying neoplastic transformation are poorly understood. We sought to evaluate the role of microRNAs in neoplasia development in this high-risk population. Experimental Design Tissue from 12 controls, 9 UC patients without neoplasia, and 11 UC patients with neoplasia was analyzed. miRNA array analysis was performed and select miRNAs assayed by real-time PCR on the discovery cohort and a validation cohort. DNA methylation of miR-193a was assessed. Following transfection of miR-193a-3p, proliferation, IL17RD expression, and luciferase activity of the 3’UTR of IL17RD were measured. Tumor growth in xenografts as well as EGFR signaling were assessed in HCT116 cells expressing IL17RD with either a mutant 3’ untranslated region (UTR) or wild-type (WT) 3’UTR. Results miR-31, miR-34a, miR-106b, and miR-193a-3p were significantly dysregulated in UC-neoplasia and adjacent tissue. Significant down-regulation of miR-193a-3p was also seen in an independent cohort of UC-cancers. Changes in methylation of miR-193a or expression of pri-miR-193a were not observed in UC-cancer. Transfection of miR-193a-3p resulted in decreased proliferation, and identified IL17RD as a direct target of miR-193a-3p. IL17RD expression was increased in UC-cancers, and miR-193a-3p treatment decreased growth and EGFR signaling of HCT116 cells in xenografts expressing both IL17RD with WT 3’UTR compared to cells expressing IL17RD with mutant 3’UTR. Conclusions miR-193a-3p is down-regulated in UC-neoplasia, and its loss promotes carcinogenesis through up-regulation of IL17RD. These findings provide novel insight into inflammation-driven CRC and could suggest new therapeutic targets in this high-risk population.
Purpose Epidermal growth factor receptors (EGFR) are required for tumor promotion by Western diet (WD). The metalloprotease, ADAM17 activates EGFR by releasing pro-EGFR ligands. ADAM17 is regulated by G-protein coupled receptors, including CXCR4. Here we investigated CXCR4-ADAM17 crosstalk and examined the role of ADAM17 in tumorigenesis. Experimental Design We used CXCR4 inhibitor, AMD3100 and ADAM17 inhibitor, BMS566394 to assess CXCR4-ADAM17 crosstalk in colon cancer cells. We compared expression of CXCR4 ligand, CXCL2, and ADAM17 in mice fed WD versus standard diet. Separately, mice were treated with marimastat, a broad-spectrum ADAM17 inhibitor, or AMD3100 to assess EGFR activation by ADAM17 and CXCR4. Using Apc mutant Min mice, we investigated effects of ADAM17/10 inhibitor INCB3619 on tumorigenesis. To assess effects of colonocyte ADAM17, mice with ADAM17 conditional deletion were treated with azoxymethane (AOM). ADAM17 expression was also compared in colonocytes from primary human colon cancers and adjacent mucosa. Results CXCL12 treatment activated colon cancer cell EGFR signals, and CXCR4 or ADAM17 blockade reduced this activation. In vivo, WD increased CXCL12 in stromal cells and TGFα in colonocytes. Marimastat or AMD3100 caused >50% reduction in EGFR signals (p<0.05). In Min mice, INCB3619 reduced EGFR signals in adenomas and inhibited intestinal tumor multiplicity (p<0.05). In the AOM model, colonocyte ADAM17 deletion reduced EGFR signals and colonic tumor development (p<0.05). Finally, ADAM17 was up-regulated >2.5-fold in human malignant colonocytes. Conclusions ADAM17 is a WD-inducible enzyme activated by CXCL12-CXCR4 signaling, suggesting the pathway: Western diet->CXCL12->CXCR4->ADAM17->TGFα‐>EGFR. ADAM17 might serve as a druggable target in chemoprevention strategies.
Hypertension is a risk factor for the cardiovascular diseases. Although, several drugs are used to treat hypertension, the success of the antihypertensive therapy is limited. Resveratrol decreases blood pressure in animal models of hypertension. This study researched the mechanisms behind the effects of resveratrol on hypertension. Hypertension was induced by using the deoxycorticosterone acetate (DOCA)-induced (15 mg/kg twice per week, subcutaneously) salt-sensitive hypertension model of Wistar rats. Hypertension caused a decrease in endotheliumdependent relaxations of the isolated thoracic aorta. Resveratrol treatment (50 mg/l in drinking water) prevented DOCA salt-induced hypertension, but did not improve endothelial dysfunction. Plasma nitric oxide (NO), asymmetric dimethylarginine (ADMA), total antioxidant capacity (TAC) and hydrogen sulfide (H 2 S) levels were not changed by DOCA salt application. However, treatment of resveratrol significantly decreased ADMA and increased TAC and H 2 S levels. NO level in circulation was not significantly changed by resveratrol. DOCA salt application and resveratrol treatment also caused an alteration in the epigenetic modification of vessels. Staining pattern of histone 3 lysine 27 methylation (H3K27me3) in the aorta and renal artery sections was changed. These results show that preventive effect of resveratrol on DOCA salt-induced hypertension might due to its action on the production of some blood biomarkers and the epigenetic modification of vessels that would focus upon new aspect of hypertension prevention and treatment.
Telomerase activity is essential for the continued growth and survival of malignant cells, therefore inhibition of this activity presents an attractive target for anti-cancer therapy. The telomerase inhibitor GRN163L, was shown to inhibit the growth of cancer cells both in vitro and in vivo. Mesenchymal stem cells (MSCs) also show telomerase activity in maintaining their self-renewal; therefore the effects of telomerase inhibitors on MSCs may be an issue of concern. MSCs are multipotent cells and are important for the homeostasis of the organism. In this study, we sought to demonstrate in vitro effects of GRN163L on rat MSCs. When MSCs were treated with 1 µM GRN163L, their phenotype changed from spindle-shaped cells to rounded ones and detached from the plate surface, similar to cancer cells. Quantitative-RT-PCR and immunoblotting results revealed that GRN163L holds MSCs at the G1 state of the cell cycle, with a drastic decrease in mRNA and protein levels of cyclin D1 and its cdk counterparts, cdk4 and cdk6. This effect was not observed when MSCs were treated with a mismatch control oligonucleotide. One week after GRN163L was removed, mRNA and protein expressions of the genes, as well as the phenotype of MSCs returned to those of untreated cells. Therefore, we concluded that GRN163L does not interfere with the self-renewal and differentiation of MSCs under short term in vitro culture conditions. Our study provides additional support for treating cancers by administrating GRN163L without depleting the body's stem cell pools.
Mesenchymal Stem Cells (MSCs) have high therapeutic value for regenerative medicine and tissue engineering due to their differentiation potential and nonimmunogenic characteristics. They are also considered as an effective in vivo delivery agent because of their ability to migrate to the site of injury. A major roadblock in their use for cell-based therapies is their rareness in vivo. Therefore, it is important to obtain increased number of functional MSCs in vitro in order to have adequate numbers for therapeutic regiments. We aimed to investigate the role of estrogen and its mechanism in obtaining more MSCs. MSCs were isolated from female and ovariectomized rats and cultured in the presence and absence of 10 −7 M estrogen. In the presence of estrogen, not only their CFU-F activity increased but also apoptotic rate decreased as shown by TUNEL staining leading to obtain more MSCs. Also the number of the cells in the colonies increased upon estrogen treatment. To reveal the mechanism of this effect, we focused on Bcl-2 family of proteins. Our immunoblotting experiments combined with knockdown studies suggested a critical role for anti-apoptotic Bcl-x L and Bcl-2. Estrogen treatment up regulated the expression Bcl-x L and Bcl-2. When we knocked down the expression of bcl-x L and bcl-2, MSCs lacking these genes showed an increase in the apoptotic rate in contrast to normal MSCs following estrogen treatment. Therefore, estrogen treatment will be of great advantage for cell-based therapies in order to get more functional MSCs and may provide opportunities to develop new strategies for debilitating diseases.
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