[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]. / Wplyw beta-karotenu na ekspresje proapoptotycznych genów BAX i CAPN2 w komórkach linii ostrej bialaczki szpikowej HL-60, U-937 i TF-1; analiza technika mikromacierzy, ilosciowej PCR i Western Blot.

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.

The effect of beta-carotene and its derivatives on cytotoxicity, differentiation, proliferative potential and apoptosis on the three human acute leukemia cell lines: U-937, HL-60 and TF-1.

The influence of beta-carotene (BC) and its derivatives on differentiation, proliferation and apoptosis in three human acute leukemia cell lines was studied. We investigated: (i) the cellular uptake of BC, (ii) the cytotoxicity, (iii) the effect on cell cycle progression and/or apoptosis. The dose- and time-dependent pattern of cellular BC uptake in all studied cell lines was seen. We did not observe any cytotoxic effect of BC and ATRA in the chosen concentrations. There was only limited effect of BC on gene expression. The microarrray analysis of U-937 cell line exposed to BC for 72 h showed an increased expression of BAX gene. This finding was confirmed by real-time Q-PCR analysis, and supported by a flow cytometry apoptosis tests. We did not observe any influence of studied components on cellular proliferation. The induction of differentiation after incubation with ATRA in HL-60 cells was noted. The induction of cellular apoptosis by BC was seen in all studied cell lines. We demonstrated that BC used in the concentrations achievable in vivo does not affect the proliferation and differentiation process of the studied leukemic cell lines, but can influence and enhance the apoptosis by modulating the expression of the regulatory genes.