Trichostatin A induces apoptosis in lung cancer cells via simultaneous activation of the death receptor-mediated and mitochondrial pathway

Trichostatin A (TSA), originally developed as an antifungal agent, is one of potent histone deacetylase (HDAC) inhibitors, which are known to cause growth arrest and apoptosis induction of transformed cells, including urinary bladder, breast, prostate, ovary, and colon cancers. However, the effect of HDAC inhibitors on human non-small cell lung cancer cells is not clearly known yet. Herein, we demonstrated that treatment of TSA resulted in a significant decrease of the viability of H157 cells in a dose-dependent manner, which was revealed as apoptosis accompanying with nuclear fragmentation and an increase in sub-G0/G1 fraction. In addition, it induced the expression of Fas/FasL, which further triggered the activation of caspase-8. Catalytic activation of caspase-9 and decreased expression of anti-aptototic Bcl-2 and Bcl-XL proteins were observed in TSA-treated cells. Catalytic activation of caspase-3 by TSA was further confirmed by cleavage of pro-caspase-3 and intracellular substrates, including poly (ADP-ribose) polymerase (PARP) and inhibitor of caspase-activated deoxyribonuclease (ICAD). In addition, a characteristic phenomenon of mitochondrial dysfunction, including mitochondrial membrane potential transition and release of mitochondrial cytochrome c into the cytosol was apparent in TSA-treated cells. Taken together, our data indicate that inhibition of HDAC by TSA induces the apoptosis of H157 cells through signaling cascade of Fas/FasL-mediated extrinsic and mitocondria-mediated intrinsic caspases pathway.

Distinct Patterns of Cleavage and Translocation of Cell Cycle Control Proteins in CD95-induced and p53-induced apoptosis

Apoptotic cell death induced by p53 occurs at a late G1 cell cycle checkpoint termed the restriction(R)point, and it has been proposed that p53-induced apoptosis causes upregulation of CD95. However, as cells with defective in CD95 signaling pathway are still sensitive to p53-induced apoptosis, CD95 cannot be the sole factor resulting in apoptosis. In addition, unlike p53-induced apoptosis, the relationship between CD95-mediated apoptosis and the cell cycle is not clearly understood. It would there-fore be worth investigating whether CD95-mediated cell death is pertinent with p53-induced apoptosis in view of cell cycle related molecules. In this report, biochemical analysis showed that etoposide-induced apoptosis caused the induction and the nuclear translocation of effector molecules involved in G1 cell cycle checkpoint. However, there was no such translocation in the case of CD95-mediated death. Thus, although both types of apoptosis involved caspase activation, the cell cycle related proteins responded differently. This argues against the idea that p53-induced apoptosis occurs through the induction of CD95/CD95L expression.

The Immunohistochemical Analysis for the Expression of Survivin, HSP, and Bcl-2 in Non-small Cell Lung Carcinoma / 결핵

BACKGROUND: Anti-apoptotic proteins may be involved in tumor development, progression and the response to treatment. Bcl-2 is by far the most studied anti-apoptotic protein. A novel infibitor of apoptosis, designat ed survivin, and the heat shock proteins (HSPs) have recently been found in many human cancers. Immunohistochemical methods were used to determine the expression level of survivin, HSP 70 and bcl-2 in non-small cell lung cancer (NSCLC) to evaluate their clinical significance. METHODS: Tissue array slides were obtained from 99 surgically resected NSCLCs. Immunohistochemical staining was performed by an immuno-peroxidase technique using an avidin-biotinylated horseradish peroxidase complex. Anti-survivin rabbit polyclonal antibodies, anti-HSP70 mouse monoclonal antibodies and anti-bcl-2 mouse monoclonal antibodies were used as the primary antibodies. RESULTS: Positive ataining of survivin was detected in 33.3% of the cases. Survivin positivity is associated with to females and recurrence. A nonstatistically significant trend toward increased survivin expression was observed in non-smokers, and its expression inversely correlated with the number of cigarettes smoked in smokers. HSP70 was detected in 84.8% but this did not correlate with the clinicopathologic characteristics. Bcl-2 was detected in 18.2% and its and its expression correlated to tumor recurrence. No significant difference in the median survival time was noted in a comparison of al cases with survivin expression and those without. There was no association betwwen HSP70 or bcl-2 expression and survival. CONCLUSIONS: Survivin expression was significantly associated with females and tumor recurrence. In addition its expression was inversely associated with the number of cigarettes smoked. However, HSP70 and bcl-2 expression were not associated with the clinical parameters or survival. This suggests that measuring the survivin levels may be useful in identifying patients at high risk for disease recurrence. Therefore, survivin might be a new diagnostic/therapeutic target in cancer.

Mechanism by which activation of ?_1-adrenoceptor before is chemia controls myocardial apoptosis / 中国病理生理杂志

AIM: To study the mechanism for biological effect of ? 1-adrenoceptors by inves tigating the molecular mechanism involving in the apoptotic processi on in myocardium. METHODS: The expressions of Bcl-2, Bax, cytochrome C, caspase-3 were determined by means of immunohistochemistry and molecular technique. RESULTS: Bcl-2 was increased but apoptosis, Bax, cytochrome C, caspase-3 were decreased when phenylephrine was used before ischemia. CONCLUSION: ? 1 -adrenoceptors may influence the expression of Bcl-2 ,change the permeabil ity of mitochondrion and adjust the expression of apoptotic protein to control apoptosis.