Reduced expression of DKK3 is associated with adverse clinical outcomes of uterine cervical squamous cell carcinoma.

OBJECTIVE: The aim of this study was to assess the expression of DKK3 protein and its target, beta-catenin, in uterine cervical squamous cell carcinoma and to determine potential clinical correlations. MATERIALS AND METHODS: Six carcinoma in-situ (CIS) tissues and 88 invasive cervical cancer tissues were included in the study. Twenty-two normal cervical tissues and one gastric cancer tissue were used as controls. The expression of DKK3 and beta-catenin proteins was evaluated by immunohistochemical analysis. Clinical and pathological parameters were obtained from medical records. Survival data were estimated using Kaplan-Meier estimates and compared with a log-rank test. Multivariate analysis was performed using the Cox regression method. RESULTS: DKK3 was predominantly present in the cytoplasm. Beta-catenin was observed only on the cellular membrane of both normal and cancer cells in contrast to earlier reports, in which beta-catenin was localized to the cytoplasm and nucleus of cancer cells. The expressions of beta-catenin and DKK3 were not correlated. Three of 6 CIS (50%) and 57 of 88 invasive cancer specimens (64.8%) had lower DKK3 expression than normal controls. DKK3 expression was decreased in a stage-dependent manner (P = 0.021). The patients with low expression of DKK3 were older than those with high expression of DKK3 (P < 0.01). Moreover, the patients with low DKK3 expression had a significantly lower 5-year disease-free survival rate than those with high DKK3 expression (P = 0.026). A multivariate analysis showed that International Federation of Gynecology and Obstetrics clinical stage and parametrial involvement were independent prognostic factors. CONCLUSION: Decreased DKK3 expression was associated with advanced International Federation of Gynecology and Obstetrics clinical stages and was predictive of lower disease-free survival in patients with cervical squamous cell carcinoma. DKK3 may be implicated in cervical carcinogenesis through a beta-catenin-independent mechanism.

Angiotensin II-induced differentiation of adipose tissue-derived mesenchymal stem cells to smooth muscle-like cells.

Angiotensin II (Ang II) is involved in the development of cardiovascular disease and vascular remodeling. In this study, we demonstrate that treatment of human adipose tissue-derived mesenchymal stem cells (hADSCs) with Ang II increased the expression of smooth muscle-specific genes, including alpha-smooth muscle actin (alpha-SMA), calponin, h-caldesmon, and smooth muscle myosin heavy chain (SM-MHC), and also elicited the secretion of transforming growth factor-beta1 (TGF-beta1) and delayed phosphorylation of Smad2. The Ang II-induced expression of alpha-SMA and delayed phosphorylation of Smad2 were blocked by pretreatment of the cells with a TGF-beta type I receptor kinase inhibitor, SB-431542, small interference RNA-mediated depletion of endogenous Smad2, and adenoviral expression of Smad7. Furthermore, the Ang II-induced TGF-beta1 secretion, alpha-SMA expression, and delayed phosphorylation of Smad2 in hADSCs were abrogated by the MEK inhibitor U0126, suggesting a pivotal role of MEK/ERK pathway in the Ang II-induced activation of TGF-beta1-Smad2 signaling pathway. The smooth muscle-like cells which were differentiated from hADSCs by Ang II treatment exhibited contraction in response to 60mM KCl. These results suggest that Ang II induces differentiation of hADSCs to contractile smooth muscle-like cells through ERK-dependent activation of the autocrine TGF-beta1-Smad2 crosstalk pathway.

Downregulation of protein kinase CKII is associated with cellular senescence.

Protein kinase CKII (CKII) plays a critical role in cell growth and proliferation. In this study, we examine how CKII activity is regulated during cellular senescence. Our results demonstrate that CKII activity apparently decreases during both replicative and H2O2-induced senescence in human diploid fibroblast IMR-90 cells. The mRNA and protein levels of CKIIalpha decreases significantly during replicative and H2O2-induced senescence, while only slight reduction in those of CKIIbeta is observed during replicative senescence. Treatment of IMR-90 cells with CKII inhibitors 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole and apigenin led cells to acquire a senescent phenotype as judged by the senescence-associated beta-galactosidase marker and overexpression of p53 and p21(Waf-1). Knockdown of CKIIalpha in IMR-90 cells by RNA interference also dramatically induced the senescent phenotype. In parallel, CKII activity was transcriptional downregulated in rat liver and testis with advancing age. Taken together, these results suggest that downregulation of CKII activity is tightly associated not only with cellular senescence but also with organism aging.

Curcumin suppresses the induction of indoleamine 2,3-dioxygenase by blocking the Janus-activated kinase-protein kinase Cdelta-STAT1 signaling pathway in interferon-gamma-stimulated murine dendritic cells.

Indoleamine 2,3-dioxygenase (IDO) catalyzes the initial and rate-limiting step in the degradation of tryptophan and is strongly induced in interferon-gamma (IFNgamma)-stimulated dendritic cells (DCs). IDO has recently been established as a key enzyme in T-cell suppression-mediated immune tolerance to tumors. STAT1 phosphorylation appears to play an important role in the control of IDO expression by IFNgamma, but the precise regulatory mechanism remains obscure. Here we present a novel mechanism of IFNgamma-induced IDO expression in bone marrow-derived dendritic cells. In addition, we demonstrate that curcumin, an active component of turmeric, significantly inhibited the induction of IDO expression and activity by IFNgamma. We found that curcumin suppressed STAT1 activation by directly inhibiting Janus-activated kinase 1/2 and protein kinase Cdelta phosphorylation in bone marrow-derived DCs, suppressing the subsequent translocation and binding of STAT1 to the GAS element of the IRF-1 promoter. Coincident with these inhibitory effects on IFNgamma-induced IDO expression, curcumin reversed IDO-mediated suppression of T-cell responses. Our results, thus, suggest that down-regulation of IDO in DCs is an important immunomodulatory property of curcumin that may be exploited therapeutically in the control of cancers.