Evaluation of combined h-TERT, bcl-2, and caspases 3 and 8 expression in cutaneous malignant melanoma based on tissue microarrays and computerized image analysis.

PURPOSE: Deregulation of apoptotic pathways in cutaneous malignant melanoma appears to be correlated with chemoresistance and poor prognosis. Furthermore, telomerase (especially h-TERT) expression induces proliferation and also represents a potential target for vaccination regarding some types of malignancies. MATERIALS AND METHODS: Using tissue microarrays (TMA) technology, 25 paraffin-embedded tissue samples of histologically confirmed malignant melanomas were cored at a diameter of 2 mm and re-embedded into one recipient block (final TMA density 24/25-96%). Immunohistochemistry (IHC) was performed by the use of anti-bcl-2, anti-caspase 3, anti-caspase 8 and anti- h-TERT antibodies. Protein expression levels were evaluated using a computerized image analysis system (CIA). SPSS (chi square test and inter-rater kappa) was used for statistical analysis. RESULTS: Strong protein expression was observed in 1/24 (4.1%), 1/24 (4.1%), 2/24 (8.2%), and 4/24 (16.4%) cases regarding h-TERT, caspase 3, caspase 8 and bcl-2, respectively. Moderate was observed in 7/24 (29.1%), 8/24 (32.2%), 5/24 (20.2%), and 8/24(32.2%) cases, whereas reduced or absent expression demonstrated 16/24 (65%), 15/24 (60.2%), 17/24 (68.5%), and 12/24 (50 %) cases. Statistical significance was assessed correlating age to caspase 3 (p=0.05), Breslow's thickness to telomerase (p=0.013) and to bcl-2 (p=0.053), Clark's level to telomerase (p=0.008) and to bcl-2 (p=0.022), and finally ulceration to telomerase expression (p=0.007). CONCLUSION: bcl-2 and telomerase expression are correlated to critical parameters of malignant melanoma, affecting its biological behavior. Furthermore, downregulation of proteins such as caspases 3/8, which normally induce apoptosis, is perhaps associated with resistance of the applied chemotherapeutic strategies in this type of malignancy.

The effects of enalapril on p53 expression in left ventricular cardiomyocytes after aortic stenosis.

ACE-inhibitors prevent the development of left ventricular hypertrophy (LVH). The tumor suppressor gene p53 up-regulates the cellular renin-angiotensin system, resulting in ANG II synthesis, which activates p53 creating a positive feedback loop. One hundred and fourteen rabbits were separated into groups A (control), B (sham-operated), C and D. In groups C and D, an aortic stenosis was performed, and in group D the animals were treated with enalapril. For p53 determination, LV specimens were examined by Western blot analysis and an immunohistochemical study was performed, except for samples from group D. In conclusion, LVH was significantly induced at 7 and 28 days after aortic stenosis with no difference between the two periods, while enalapril prevented hypertrophy in these two groups. p53 was transcriptionally activated and immunoreactively present after acute pressure overload as well as in the sham-operated group. Enalapril decreased the p53 expression at 180 min, 7 and 28 days following aortic stenosis.