Expression of Caveolin-1 reduces cellular responses to TGF-beta1 through down-regulating the expression of TGF-beta type II receptor gene in NIH3T3 fibroblast cells.

Transcriptional repression of Transforming Growth Factor-beta type II receptor (TbetaRII) gene has been proposed to be one of the major mechanisms leading to TGF-beta resistance. In this study, we demonstrate that expression of Caveolin-1 (Cav-1) gene in NIH3T3 fibroblast cells down-regulates the expression of TbetaRII gene in the transcriptional level, eventually resulting in the decreased responses to TGF-beta. The reduced expression of TbetaRII gene by Cav-1 appeared to be due to the changes of the sequence-specific DNA binding proteins to either Positive Regulatory Element 1 (PRE1) or PRE2 of the TbetaRII promoter. In addition, Cav-1 expression inhibited TGF-beta-mediated cellular proliferation and Plasminogen Activator Inhibitor (PAI)-1 gene expression as well as TGF-beta-induced luciferase activity. Furthermore, the inhibition of endogeneous Cav-1 by small interfering RNA increased the expression of TbetaRII gene. These findings strongly suggest that expression of Cav-1 leads to the decreased cellular responsiveness to TGF-beta through down-regulating TbetaRII gene expression.

Tumor carbonic anhydrase 9 expression is associated with the presence of lymph node metastases in uterine cervical cancer.

Tumor hypoxia has a pronounced effect on malignant progression and metastatic spread of human tumors. As carbonic anhydrases (CA) 9 and 12 are induced by the low-oxygen environment within tumors, we investigated the relationship between the expression of these two CA and the presence of metastatic lymph nodes (LN) in uterine cervical cancer. CA9/CA12 expression was evaluated histochemically in primary cervical cancer tissues of 73 patients who underwent laparoscopic LN staging and two patients with clinical staging before definitive radiotherapy at the National Cancer Center, Korea. We also evaluated CA9 expression in 33 patients with pathologically confirmed metastatic LN. CA9 expression in the primary tumors was significantly associated with LN metastasis (P = 0.03) and poorer disease-free survival (relative risk, 6.1; 95% confidence interval, 1.3-28.3, P = 0.02, multivariate analysis), whereas CA12 expression did not show such a relationship. In addition, 21 of 24 metastatic LN revealed similar CA9 expression (P = 0.001), suggesting that CA9-expressing tumor cells had a higher metastatic potential. CA9 was expressed in 45 of 75 (60%) primary tumors, with positive tumor cells observed predominantly in the area away from the blood vessels. In contrast, CA12 expression was observed in only 29 of 74 primary tumors (39%), without a specific pattern. These findings indicate that expression of CA9, but not CA12, in tumors is associated with the presence of LN metastases and poorer prognosis. Selective application of new treatment modalities based on CA9 expression to prevent LN metastases may improve overall treatment outcome in patients with uterine cervical cancer.

A new anti-inflammatory agent KL-1037 represses proinflammatory cytokine and inducible nitric oxide synthase (iNOS) gene expression in activated microglia.

Excessive proinflammatory cytokine and NO production by activated microglia play a role in neurodegenerative disorders. In this study, we found that a new compound KL-1037 suppressed LPS-induced NO release/inducible nitric oxide synthase expression in BV2 mouse microglial cells. In addition, KL-1037 prominently diminished LPS-induced production of pro-inflammatory cytokines such as TNF-alpha, IL-1 beta and IL-6, while it increased anti-inflammatory IL-10 and TGF-beta 1 production. By RNase protection assay and RT-PCR, we showed that KL-1037 regulated iNOS and cytokines at transcriptional or post-transcriptional level. Further analysis of molecular mechanisms revealed that KL-1037 prominently increased intracellular cAMP levels and potentiated LPS-induced pCREB expression. However, LPS-induced MAP kinase or NF-kappa B activities were slightly or little changed by KL-1037. Treatment with cAMP antagonist or IL-10 neutralizing antibody completely reversed upregulation of IL-10 and partially repression of TNF-alpha or NO induced by KL-1037. These data suggest that microglial inactivation by KL-1037 is at least in part due to activation of PKA pathway and/or upregulation of IL-10. Thus, repressing proinflammatory cytokines and iNOS gene expression in activated microglia by KL-1037 may provide potential therapeutic strategies for various neurodegenerative diseases including ischemic cerebral disease.