Bis(benzoyl) phosphate inactivators of beta-lactamase C from Mtb.

The class A ß-lactamase BlaC is a cell surface expressed serine hydrolase of Mycobacterium tuberculosis (Mtb), one of the causative agents for Tuberculosis in humans. Mtb has demonstrated increased susceptibility to ß-lactam antibiotics upon inactivation of BlaC; thus, making BlaC a rational enzyme target for therapeutic agents. Herein, we present the synthesis and structure-activity-relationship data for the 1st-generation library of bis(benzoyl) phosphates (1-10). Substituent effects ranged from σp = -0.27 to 0.78 for electronic and π = -0.41 to 1.98 for hydrophobic parameters. Compounds 1, 4 and 5 demonstrated the greatest inhibitory potency against BlaC in a time-dependent manner (kobs = 0.212, 0.324, and 0.450 mn-1 respectively). Combined crystal structure data and mass spectrometric analysis of a tryptic digest for BlaC inactivated with 4 provided evidence that the mechanism of inactivation by this bis(benzoyl) phosphate scaffold occurs via phosphorylation of the active-site Ser-70, ultimately leading to an aged form of the enzyme.

Therapist Use of Specific and Nonspecific Strategies Across Two Affect-Focused Psychotherapies for Depression: Role of Adherence Monitoring.

Psychotherapists routinely use both specific and non-specific strategies to deliver empirically supported treatments (ESTs). Psychotherapy adherence monitoring has traditionally focused on assessing therapist use of EST-specific strategies (to distinguish between ESTs), paying less attention to non-specific techniques common to multiple psychotherapies. This study used the Collaborative Study Psychotherapy Rating Scale (CSPRS) to evaluate therapist use of both specific and non-specific techniques in two affect-focused ESTs for depression. Blinded raters evaluated 180 recorded sessions of interpersonal psychotherapy (IPT) and brief supportive psychotherapy (BSP). Because IPT and BSP both emphasize attention to affective states and developing a warm therapy relationship, we expected overlap across scales measuring therapist warmth, empathy, and focus on feelings. In contrast, we expected differences in scales measuring therapist directiveness, as well as IPT- and BST-specific interventions. Results showed raters displayed good inter-rater reliability on primary subscales and could discriminate between two treatments with considerable overlap. Both IPT and BSP therapists used similarly high levels of non-specific, facilitative interventions. Expectedly, IPT therapists were more directive and used more IPT-specific strategies, while BSP therapists utilized more non-directive, supportive strategies. Unexpectedly, BSP therapists showed greater focus on feelings than IPT therapists. Exploratory analyses suggested that greater focus on feelings in early sessions was associated with greater depressive symptom reduction in the first eight weeks of treatment for both ESTs. Additional treatment adherence research is needed to investigate both shared and distinctive features of ESTs, as well as the effect of the relative use of specific versus non-specific interventions on psychotherapy outcomes.

Development of inhibitor-directed enzyme prodrug therapy (IDEPT) for prostate cancer.

Prostate cancer (PCa) is the second most common cause of cancer death among American men after lung cancer. Unfortunately, current therapies do not provide effective treatments for patients with advanced, metastatic, or hormone refractory disease. Therefore, we seek to generate therapeutic agents for a novel PCa treatment strategy by delivering a suicide enzyme (yCDtriple) to a cell membrane bound biomarker found on PCa cells (prostate-specific membrane antigen (PSMA)). This approach has resulted in a new PCa treatment strategy reported here as inhibitor-directed enzyme prodrug therapy (IDEPT). The therapeutic agents described were generated using a click chemistry reaction between the unnatural amino acid (p-azidophenylalanine (pAzF)) incorporated into yCDtriple and the dibenzylcyclooctyne moiety of our PSMA targeting agent (DBCO-PEG4-AH2-TG97). After characterization of the therapeutic agents, we demonstrate significant PCa cell killing of PSMA-positive cells. Importantly, we demonstrate that this click chemistry approach can be used to efficiently couple a therapeutic protein to a targeting agent and may be applicable to the ablation of other types of cancers and/or malignancies.