BH3 peptidomimetics potently activate apoptosis and demonstrate single agent efficacy in neuroblastoma.

The major impediment to cure for many malignancies is the development of therapy resistance with resultant tumor progression. Genetic alterations leading to subversion of inherent apoptosis pathways are common themes in therapy resistance. Bcl-2 family proteins play a critical role in regulating mitochondrial apoptosis that governs chemotherapeutic effects, and defective engagement of these pathways contributes to treatment failure. We have studied the efficacy of BH3 peptidomimetics consisting of the minimal death, or BH3, domains of the proapoptotic BH3-only proteins Bid and Bad to induce apoptosis using neuroblastoma (NB) as a model system. We demonstrate that BH3 peptides, modified with an arginine homopolymer for membrane transduction (called r8-BidBH3 and r8-BadBH3, respectively), potently induce apoptosis in NB cells, including those with MYCN amplification. Cell death is caspase 9 dependent, consistent with a requirement for the intrinsic mitochondrial pathway. Substitutions at highly conserved residues within the r8-BidBH3 peptide abolish apoptotic efficacy supporting activity through specific BH domain interactions. Concomitant exposure to r8-BadBH3 and r8-BidBH3 at sublethal monotherapy doses revealed potent synergy consistent with a competitive displacement model, whereby BH3 peptides displace sequestered BH3 proteins to induce cell death. Further, BH3 peptides demonstrate antitumor efficacy in a xenograft model of NB in the absence of additional genotoxic or trophic stressors. These data provide proof of principle that targeted re-engagement of apoptosis pathways may be of therapeutic utility, and BH3-like compounds are attractive lead agents to re-establish therapy-induced apoptosis in refractory malignancies.

Findings on a relationship between type A behavior and headaches.

Based on answers to a headache questionnaire college women were classified on a two-dimensional array according to their relative frequencies of both vascular (migraine) and tension (muscle contraction) pain. The various groups were then compared on a measure of the coronary-prone Type A behavior pattern. In two independent surveys, one with 237 respondents and one with 206 respondents, increasing frequencies of both types of headaches were significantly associated with higher scores on the Type A scale from the Jenkins Activity Survey. The findings support prior data from a client population, also reported, and suggest appropriate therapeutic interventions for headache relief. They also clearly show that a behavior pattern which has been associated with coronary artery disease now can be considered to have implications for other problems as well.