Current guidelines in defining therapeutic strategies

Emerging therapeutic options for B-cell disorders: idiopathic thrombocytopenic purpura and chronic lymphocytic leukemia

B-cell disorders include a large group of malignant and nonmalignant diseases with tremendous variation in incidence, natural history, treatment, and prognosis. This article will focus on adult idiopathic thrombocytopenic purpura (ITP) and chronic lymphocytic leukemia (CLL). Clinicians must individualize treatment for ITP and CLL to each patient. Observation without intervention is appropriate for some patients, whereas immediate treatment is indicated for others. Deciding when to treat and which agents to use can be difficult, but new therapeutic options are emerging for both conditions.

Xanthohumol kills B-chronic lymphocytic leukemia cells by an apoptotic mechanism

B-chronic lymphocytic leukemia (B-CLL) is an indolent lymphoid malignancy with variable prognosis. Adverse prognostic factors comprise treatment resistance, cytogenetics (11q- and 17p-), the presence of unmutated Ig genes, and the more comprehensive activation marker Zap 70. In contrast to diminished sensitivity to chemotherapy, Zap 70+ B-CLL cells retain their responsiveness to manipulation of signal transduction and monoclonals. Xanthohumol (XA) has recently been documented to have an impact on breast cancer cell growth and invasiveness in vitro. Based on these observations, lymphocytes from patients with B-CLL were cultured in the presence of XA in vitro. XA induced a dose-dependent killing of B-CLL cells at an LD(50) ((24 h)) of 24.4 +/- 6.6 microM, independent of known adverse prognostic factors including functional loss of p53. Cell death was associated with poly (ADP)-ribose polymerase cleavage and annexin V positivity, suggestive of an apoptotic mechanism. Surprisingly, p 70(S 6 K) phosphorylation was stimulated upon XA treatment. In conclusion, XA has an antitumor activity on B-CLL cells in vitro. The molecular mechanisms behind this pro-apoptotic effect deserve further investigation.