Table 6

Effects of TNFα neutralization on the response to ara-C

TreatmentCotreatmentCeramide levelsSAPK activityApoptosis
pmol/106 cells % control % total
ControlCarrier71  ± 18100  ± 82  ± 1
ara-CCarrier393  ± 866-a 846  ± 46-a 31  ± 36-a
ControlAnti-TNFα mAb68  ± 24175  ± 92  ± 1
ara-CAnti-TNFα mAb89  ± 216-b 367  ± 76-b 33  ± 86-a
ControlrhsTNF-RI68  ± 29189  ± 42  ± 1
ara-CrhsTNF-RI75  ± 256-b 178  ± 46-b 28  ± 46-a

HL-60 cells in complete medium were treated with ara-C (10 μm) in the presence of a monoclonal antibody directed against rhTNFα (anti-TNFα mAb; 3.25 μg/ml), soluble type I TNF receptor cytoplasmic domain (rhsTNF-RI; 200 ng/ml), or inactive carrier (0.2% BSA in PBS). Cells were prepared for measurement of cellular ceramide, SAPK activity, and apoptotic cell death as before.

    • 6-a Increased versus vehicle (p < 0.05).

    • 6-b Decreased versus ara-C (p < 0.05).