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VOL. 72 (1), 27-36, 2006 ANTIAPOPTOTIC PROTEINS BCL2 AND BCLX...

significantly inhibited the growth of Kbcl2v and KbclX cells, athough
to a lesser extent than K562.

It was conceivable that imatinib impaired the expression of the
ectopic Bcl2 or BclX genes. To test this possibility we analysed the
Bcl2 mRNA in Kbcl2v cells treated with imatinib. The results (Fig.
1B) showed that imatinib did not affect Bcl2 expression at
concentrations that were effective on the growth of Kbcl2v cells. As
previously described, parental K562 do not express Bcl-2 (9).

FIGURE 1. Effect of imatinib on K562 expressing Bcl-2 and Bcl-XL. (A) Inhibition of
proliferation determined by DNA synthesis in K562, Kbcl2v and KbclX treated for
the indicated period of times with 0.5 µM and 2.5 µM imatinib. (B) BCL2 expression
in K562 and Kbcl2v cells treated for 1, 2 or 3 days with 0.5 µM imatinib, as analyzed by
Northern blot analysis. A picture of the filter after transfer showing the rRNAs
stained with ethidium bromide is shown to assess the loading and integrity of the RNAs.

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