[Beta-carotene regulates the expression of proapoptotic BAX and CAPN2 in HL-60, U-937 and TF-1 - human acute myeloid leukemia cell lines; microarray, RQ-PCR and Western Blot analysis].

Beta carotene (BC) is a nutritional compound widespread in foods which can influence vital cellular functions--differentiation, proliferation and apoptosis of normal and cancer cells. However its role in the carcinogenesis remains controversial. We performed a microarray expression analysis in three human acute leukemia cell lines (HL-60, U937 and TF-1) exposed to 10mM BC and found that BC stimulated the apoptosis in all studied cell lines. This effect was most evident in the HL-60 cell line and correlated with increased expression of proapoptotic BAX and CAPN2 genes. The micro-array findings were replicated by the quantitative BAX and CAPN2 expression analysis using real-time PCR and by Western Blot on protein level. The biological tests (TUNEL method) for apoptosis showed consistent proapoptotic effects in all studied cell lines. In this paper the stimulatory effect of BC on apoptosis (enhanced expression of proapoptotic genes and proteins) in human acute myeloid leukemia cells was confirmed. The most potent activation of apoptosis in the HL-60 cells is in line with other investigators observations suggesting distinct molecular mechanism of apoptosis stimulation by BC in different human acute myeloid leukemia cells.