Abstract
Curcumin, a major active component of turmeric, has been recognized as an anticarcinogenic agent because of its propensity to induce apoptosis in vivo and in vitro. Previously, we showed that curcumin protects cells against oligonucleosomal DNA fragmentation and induces a novel apoptosis-like pathway in Jurkat cells (Piwocka et al. Exp Cell Res 249, 299-307, 1999). Here, we have studied the ability of curcumin to induce cell death in other human and rodent transformed as well as normal cells. Normal cells were quiescent or stimulated to proliferate. We showed that 50 microM pigment is able to induce cell death in all studied cells, but cell death symptoms varied for different cells. All the cells died as assessed by the TdT-mediated UTP nick end labeling method or trypan blue exclusion test. No one type of cells showed oligonucleosomal DNA fragmentation (DNA "ladder") due to curcumin action, although in HL-60 cells, we were able to observe sub-G1 formation and caspase-3 activation. Together, these data showed that curcumin induces cell death in all tested cells that can be classified as apoptosis-like, and only in HL-60 cells can it be recognized as classical apoptosis.
