Telomerase activity and Bcl-2 expression in human breast cancer

p53, BCL-2 and BAX in non-small cell lung cancer brain metastases: a comparison of real-time RT-PCR, ELISA and immunohistochemical techniques

OBJECTIVES

Metastasis to the brain is a severe and common complication in non-small cell lung cancer (NSCLC). The examination of cell cycle associated genes in these lesions may contribute to the understanding of metastatic growths in the central nervous system. The aim of this study was to evaluate the p53, BCL-2 and BAX mRNA and protein expression in NSCLC brain metastases in comparison with matched primary tumors.

METHODS

For quantitative TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), fresh frozen tumor specimens from 12 patients with NSCLC brain metastases were available. For immunohistochemical staining, 78 surgically removed NSCLC brain metastases were used. PCR results were analysed using the DeltaDeltaCT method. Staining was analysed using a modified immunoreactive score (IRS).

RESULTS

Overall, p53, BCL-2 and BAX expression values in brain metastases and primary tumors showed a wide variety. The comparison of different techniques revealed different findings on the mRNA and protein level. Herein, PCR and ELISA revealed no clear tendencies. In contrast, immunohistochemistry showed significant overexpression of BAX and underexpression of BCL-2 in brain metastases.

CONCLUSION

A high variability in the expression of p53, BCL-2 and BAX in NSCLC exists in brain metastases. Immunohistochemistry revealed overexpression of BAX and underexpression of BCL-2 in brain metastases, whereas there were no clear tendencies using PCR and ELISA techniques. More insights into the BAX/BCL-2 interaction are needed before reasonable conclusions can be drawn from the existing data.

Reduced mRNA and protein expression of BCL-2 versus decreased mRNA and increased protein expression of BAX in breast cancer brain metastases: a real-time PCR and immunohistochemical evaluation

OBJECTIVES

Brain metastases are an increasingly common complication in breast cancer patients. Apoptosis regulating genes are promising candidates for further treatment options. We examined the mRNA and protein expression of p53, BCL-2 and BAX in breast cancer brain metastases versus primary tumors.

METHODS

In a two-step approach p53, BCL-2 and BAX mRNA expression in ductal invasive breast cancer brain metastases was examined by: (1) reverse transcription-polymerase chain reaction (RT-PCR) mRNA expression screening (band appearance in relation to an internal standard) and (2) quantitative real-time RT-PCR (CT-values in relation to an internal standard). Protein expression using immunohistochemistry. Results were compared with primary tumors.

RESULTS

We found significantly lower BCL-2 mRNA and protein expression in breast cancer brain metastases versus primary tumors. P53 mRNA and protein expression was also lower in metastases. However, this difference was only significant on mRNA but not on the protein level. BAX expression evaluation revealed was contradictory results: mRNA expression was significantly lower whereas protein expression was significantly higher in metastatic lesions.

DISCUSSION

The mRNA and protein expression of p53 and BCL-2 seems to be reduced in breast cancer brain metastases. BAX mRNA and protein may be regulated differentially in metastatic lesions.

Fumagillin treatment of hepatocellular carcinoma in rats: An in vivo study of antiangiogenesis

AIM: To investigate the effect and possible mechanisms of antiangiogenesis therapy for HCC in rats.

METHODS: Adult male LEW/SsN rats were divided into 3 groups, 25 animals each. Group A was the control group. Groups B and C were given diethylnitrosamine, 5 mg/kg/d. In addition, group C rats received an intraperitoneal injection of fumagillin, 30 mg/(kg·d). Five animals in each group were killed at 6^th, 12^th, 18^th, 20^th and 24^th wk to evaluate the development of HCC and metastasis. Weight of the rats, liver tumors, and number of organs involved by HCC were measured at each stage. We compared methionine aminopeptidase-2 (MetAP-2) mRNA, Bcl-2 mRNA, telomerase mRNA, and telomerase activity at 24^th wk in the liver tissue of group A rats and tumor tissue of HCC from group B and C rats.

RESULTS: No HCC developed in group A, but tumors were present in group B and C rats by the 18^th wk. At wk 20 and 24, the median liver weight in group B was 0.64 g (range: 0.58-0.70 g) and 0.79 g (range: 0.70-0.90 g) (P = 0.04), and that in group C was 0.37 g (range: 0.35-0.42 g) and 0.39 g (range: 0.35-0.47 g) (P = 0.67). The liver weight in group C rats was significantly lower than that in group B rats (P = 0.009). At the same time, the median metastasis score (number of organ systems involved) was 3 (range 2-3) in group B, and 1 (range 1-2) in group C, a significant difference between the groups (P = 0.007, 0.004). The levels of MetAP-2 mRNA were significantly higher in groups B and C than in group A (P = 0.025), and significantly higher in group C than in group B (P = 0.047). The level of Bcl-2 mRNA was significantly higher in group B than in group A (P = 0.024), but lower in group C than in group B, although not significantly (P = 0.072). Telomerase mRNA was significantly higher in group B than in group A (P = 0.025), but significantly lower in group C than in group B (P = 0.016). The same inter-group relationship was also true for telomerase activity (P = 0.025 and 0.046).

CONCLUSION: Fumagillin effectively inhibits both liver tumor growth and metastasis in rats in vivo. A possible mechanism is fumagillin-induced inhibition of MetAP-2, which plays an essential role in endothelial cell proliferation. Inhibition of MetAP-2 also results in inhibition of Bcl-2 and telomerase activity.