Androstenediol inhibits the trauma-hemorrhage-induced increase in caspase-3 by downregulating the inducible nitric oxide synthase pathway

2007 ◽  
Vol 102 (3) ◽  
pp. 933-941 ◽  
Author(s):  
Juliann G. Kiang ◽  
Russell M. Peckham ◽  
Leah E. Duke ◽  
Tomoharu Shimizu ◽  
Irshad H. Chaudry ◽  
...  

Soft tissue trauma and hemorrhage (T-H) diminishes various aspects of liver function, while it increases hepatic nitrate/nitrite, inducible nitric oxide synthase (iNOS), and endothelin-1 levels. Treatment with androstenediol (AED) inhibits the T-H-induced alterations of the above parameters. We sought to identify the molecular events underlying the beneficial effect of AED. Exposure of rats to T-H significantly increased the caspase-3 activity and protein, whereas treatment with AED significantly limited these increases. AED treatment also suppressed the T-H-induced increase in iNOS by effectively altering the levels of key transcription factors involved in the regulation of iNOS expression. Immunoprecipitation and immunoblotting analyses indicate that T-H increased apoptosome formation, and AED treatment significantly decreased it. Modulating the iNOS protein by transfecting cells with iNOS gene or small interfering RNA further confirmed the correlation between iNOS and caspase-3. Our data indicate that AED limits caspase-3 expression by suppressing the expression of transcription factors involved in the production of iNOS, resulting in decreased apoptosome. AED can potentially be a useful adjuvant for limiting liver apoptosis following T-H shock.

2007 ◽  
Vol 103 (3) ◽  
pp. 1045-1055 ◽  
Author(s):  
Juliann G. Kiang ◽  
Phillip D. Bowman ◽  
Xinyue Lu ◽  
Yansong Li ◽  
Brian W. Wu ◽  
...  

Hemorrhage has been shown to increase inducible nitric oxide synthase (iNOS) and deplete ATP levels in tissues and geldanamycin limits both processes. Moreover, it is evident that inhibition of iNOS reduces caspase-3 and increases survival. Thus we sought to identify the molecular events responsible for the beneficial effect of geldanamycin. Hemorrhage in mice significantly increased caspase-3 activity and protein while treatment with geldanamycin significantly limited these increases. Similarly, geldanamycin inhibited increases in proteins forming the apoptosome (a complex of caspase-9, cytochrome c, and Apaf-1). Modulation of the expression of iNOS by iNOS gene transfection or siRNA treatment demonstrated that the level of iNOS correlates with caspase-3 activity. Our data indicate that geldanamycin limits caspase-3 expression and protects from organ injury by suppressing iNOS expression and apoptosome formation. Geldanamycin, therefore, may prove useful as an adjuvant in fluids used to treat patients suffering blood loss.


2002 ◽  
Vol 126 (6) ◽  
pp. 686-691
Author(s):  
George G. Chen ◽  
Janet F. Y. Lee ◽  
Ursula P. F. Chan ◽  
Hu Xu ◽  
Ping C. Ip ◽  
...  

Abstract Context.—Disturbance in apoptosis has been proposed as one of the mechanisms involved in the immune response targeting tumor outgrowth. How colorectal cancer cells escape from attack by the immune system is not yet fully understood. Objective.—To investigate apoptotic molecules associated with colorectal cancer counterattack. Design and Setting.—Tissue samples of colon from 12 patients with colorectal cancer were collected and analyzed by immunostaining. In addition to tumorous tissues, corresponding nontumorous specimens of colon were obtained as controls. Main Outcome Measures.—We examined the expression of Bcl-2, Bcl-xl, Bax, caspase-3, and inducible nitric oxide synthase in infiltrating mononuclear cells of colorectal cancer tissues and also in colorectal cancer tissues. The TUNEL assay was used to detect in situ apoptosis. Results.—Apoptosis was barely detectable in specimens of colorectal cancer, which was consistent with an increase in Bcl-2 level and a decrease in caspase-3 level. In contrast, infiltrating mononuclear cells of tumorous tissues showed a marked increase in apoptosis compared with those of nontumorous tissues. The increased apoptosis might have resulted from an imbalance of antiapoptotic and proapoptotic molecules, as reflected by reduction of Bcl-2 level and elevation of Bax level. The elevated caspase-3 levels found in this study could be a downstream effector of the Bcl-2 and Bax apoptotic pathways. A significant increase in inducible nitric oxide synthase observed in the infiltrating mononuclear cells might contribute to immunosuppression seen in colorectal cancer. Conclusion.—It is tempting to speculate that aberrant expression of apoptotic molecules and inducible nitric oxide synthase in infiltrating mononuclear cells provides the underlying mechanism through which colorectal cancer cells escape attack by the immune system and subsequently grow without control.


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