Involvement of human beta-defensin-2 in regulation of malignant potential of cultured human melanoma cells

BACKGROUND AND AIM

Human beta-defensin-2 (hBD-2) is an antimicrobial cationic peptide capable to control human carcinoma cell growth via cell cycle regulation. The present study was aimed on determination of hBD-2 influence on the growth patterns and malignant potential of cultured human melanoma cells.

METHODS

The study was performed on cultured human melanoma cells of mel Z and mel Is lines treated with recombinant hBD-2 (rec-hBD-2); cell viability, proliferation, cell cycle distribution, and anchorage-independent growth were analyzed using MTT test, direct cell counting, flow cytometry, and colony forming assay respectively. Expression and/or phosphorylation levels of proteins involved in cell cycle control were evaluated by Western blotting.

RESULTS

The treatment of mel Z and mel Is cells with rec-hBD-2 in a concentration range of 100-1000 nM resulted in a concentration-dependent suppression of cell proliferation, viability, and colony forming activity. It has been shown that rec-hBD-2 exerts its growth suppression effects via significant downregulation of B-Raf expression, activation of pRB and upregulation of p21(WAF1) expression, downregulation of cyclin D1 and cyclin E resulting in cell cycle arrest at G1/S checkpoint.

CONCLUSION

According to obtained results, hBD-2 exerts its growth suppression effect toward human melanoma cells via downregulation of B-Raf, cyclin D1 and cyclin E expression, upregulation of p21(WAF1) expression and activation of pRB.

Effects of N-acylethanolamines and various antimitotic agents on apoptotic DNA fragmentation in conventionally normal and tumor tissue of human adrenals

AIM

To study effects of N-acylethanolamines (NAE) and various antimitotic agents: taxol, colchicine, and cytochalasin B on the DNA fragmentation extent in conventionally normal (CNT) and tumor tissue of human adrenal cortex.

METHODS

Six types of adrenal tumor tissue of 84 patients were analyzed. Slices of tissue was incubated at 37 degrees C for 3 h in the presence of NAEs and antimitotics, DNA was extracted and analysed in agarose gel.

RESULTS

It was established that NAEs enhanced apoptosis in conventionally normal and tumor tissue of adrenal glands. In general, tumor tissue was more sensitive to NAEs and antimitotic compounds than conventionally normal tissue. NAEs in combination with colchicine and cytochalasin B enhanced DNA fragmentation in some types of tumor tissue and did not influence, or even reduced it in CNT. Taxol revealed selective action depending on tumor tissue type. Considerable individual differences were reported in sensitiveness of different types of tumors to the NAEs and antimitotic agents.

CONCLUSIONS

Taxol and combination of NAEs with colchicine and cytochalasin B are inductors of apoptosis in the adrenal tumor cells and thus promising for further investigation.