Use of competitive pcr to monitor expression of the bcl-2. bcl-x. mcl-1. box. bak and bfl-1 genes during the induction of apoptosis in human haematopoietic cell lines

We have developed a competitive PCR system to follow changes in the relative abundance of the major mRNAs encoding Bcl-2, Bel-XL, Bcl-xs, Mcl-1, Bax, Bak and Bfl-1. These proteins are all members of the family of human proteins related to the Ccenorhabditis elegans apoptosis-regulating protein Ced-9. Bcl2 and BC!-XL (and probably also Mcl-1 and Bfl-1) inhibit or delay apoptosis, whereas Bax, Bak and Bcl-xs promote apoptosis. Using this system we have monitored changes in the expression of these genes in three human haematopoietic cell lines following treatments that induce cell death by apoptosis. The human cell lines used were Jurkat (T-cell leukaemia), HL60 (promyelocytic leukaemia) and TF1 (IL-3-dependent erythroleukaemia). The treatments used to induce apoptosis were X-irradiation, treatment with the topoisomerase II-inhibiting chemotherapeutic agent etoposide (VP-16) and cytokine deprivation (IL-3 withdrawal).