Modification of carboplatin by Jurkat cells

Using [¹H,¹⁵N] heteronuclear single quantum coherance (HSQC) NMR and ¹⁵N-labeled carboplatin, 1, we show that Jurkat cells affect the rate of disappearance of the HSQC NMR peak in culture medium for this Pt²⁺ anticancer drug. The decay or disappearance rate constant for 1 in culture medium containing cells is k₁ = k_c [CO₃^{2 -}] + k_m + k_u N, where k_c is the rate constant for reaction of 1 with carbonate in the medium, k_m is the rate constant for reaction of 1 with all other components of the medium, and k_u is the rate constant for reaction of 1 with cells having a number density N in the medium. Since Jurkat cells only take up a small amount of the platinum present in the medium (<1%), the observed disappearance of the HSQC NMR peak for 1 cannot be due to uptake of carboplatin by the cells.