Processing 2‑Methyl‑l‑Tryptophan through Tandem Transamination and Selective Oxygenation Initiates Indole Ring Expansion in the Biosynthesis of Thiostrepton

Thiostrepton (TSR), an archetypal member of the family of ribosomally synthesized and post-translationally modified thiopeptide antibiotics, possesses a biologically important quinaldic acid (QA) moiety within the side-ring system of its characteristic thiopeptide framework. QA is derived from an independent l-Trp residue; however, its associated transformation process remains poorly understood. We here report that during the formation of QA, the key expansion of an indole to a quinoline relies on the activities of the pyridoxal-5′-phosphate-dependent protein TsrA and the flavoprotein TsrE. These proteins act in tandem to process the precursor 2-methyl- l-Trp through reversible transamination and selective oxygenation, thereby initiating a highly reactive rearrangement in which selective C2–N1 bond cleavage via hydrolysis for indole ring-opening is closely coupled with C2′–N1 bond formation via condensation for recyclization and ring expansion in the production of a quinoline ketone intermediate. This indole ring-expansion mechanism is unusual, and represents a new strategy found in nature for l-Trp-based functionalization

Molecular Profiling of Pooled Circulating Tumor Cells from Prostate Cancer Patients Using a Dual-Antibody-Functionalized Microfluidic Device

To capture both epithelial and mesenchymal subpopulations of CTCs at different metastatic stages of PCa patients, here we constructed a novel dual-antibody-functionalized microfluidic device by employing antibodies against PSMA and EpCAM. In vitro experiments with the dual capture system for capturing both LnCAP and LnCAP-EMT cells have shown significantly enhanced capture efficiency as compared to that of the EpCAM single capture system. Furthermore, the dual capture system could successfully identify CTCs in 20 out of 24 (83.3%) PCa patients, and the CTCs counts from the dual capture system were statistically correlated with the TNM stage of patients (<i>P</i> < 0.05), while conventional diagnostic methods, such as serum PSA level and Gleason score, failed to correlate to patient TNM stages. To further explore potential clinical application of our dual capture system, captured CTCs were recovered and subjected to qRT-PCR to quantify known factors involved in PCa development and therapy. The results demonstrated that the combined detection of SChLAP1 and PSA in CTCs is a potential marker for identifying patients with metastatic PCa, while detection of AR and PD-L1 in CTCs may have the potential to determine the sensitivity of PCa patients to androgen deprivation therapy and immunotherapy, respectively. Taken together, the dual-antibody-functionalized microfluidic device established in our study overcomes the limitations of some CTC capture platforms that only detect epithelial or mesenchymal CTCs in PCa patients, and detection of the PCa-related RNA signatures from purified CTCs holds great promise to offer warnings for early metastasis of PCa and may provide guidance for therapy decisions

Significant covariate-parameter correlations after inclusion of single genetic covariates.

<p>Comparison of OFV was made between models with single genetic covariates and the base model, using the reduced dataset with deletion of subjects having missing values on each individual genetic covariate. Δ OFV, change in objective function value.</p

Association of PGx, PK and bilirubin from the phase I dataset.

<p>Flavo-G PK parameter estimates from 27 patients were evaluated for relationships with PGx. Fewer TA repeats in the UGT1A1 promoter were weakly associated with lower flavo-G Cmax (Panel A) and AUC (Panel B). For SLCO1B1, the rs2306283 SNP correlated with flavo-G plasma concentrations (the total time flavo-G plasma concentrations were below 1.5 µM, p = .019; Panel C, one outlier removed). For ABCG2, the rs1564481 SNP was associated with flavo-G AUC (p = .050; Panel D) and the rs2231142 SNP was associated with flavopiridol AUC (p = 0.08, Panel E). The SLCO1B1 rs3829310 minor C allele was associated with higher baseline total bilirubin (p = .011; Panel F). For plots A and B, the x-axis indicates the number of promoter TA repeats for both gene copies (6.7 = 6 and 7 TA repeats; 7 = 7 TA repeats for each gene copy; 7.8 = 7 and 8 TA repeats; 8 = 8 TA repeats for each gene copy).</p

Final model parameter estimates.

<p>The reduced dataset with 35 subjects and 388 plasma concentrations was used. Parameters: CL, clearance; V1, volume of central compartment; Q, intercompartmental clearance; V2, volume of peripheral compartment (units are noted in parenthesis). BSV and BOV are listed as %CV. Θ, typical value of the PK parameters; BSV, between-subject variability; BOV, between-occasion variability.</p

Demographics and baseline labs of patients included in pharmacogenetic analyses (n = 35).

<p>Demographics and baseline labs of patients included in pharmacogenetic analyses (n = 35).</p

List of primers used for cloning, sequencing, and mutagenesis of SLCO1B1.

<p>List of primers used for cloning, sequencing, and mutagenesis of SLCO1B1.</p

Population estimates from final model and bootstrap analysis.

<p>Relative bias,i(%) = (Pbs,i−Pest,i)/Pest,I×100; Pbs,i: mean of parameter i estimate from bootstrap; Pest,i: final parameter i estimate.</p

Six significant covariate-parameter correlations after inclusion of single demographic or lab covariates.

<p>Comparison of OFV is made between model with single covariate and the base model. Δ OFV, change in objective function value.</p

Association of PGx and PK from the phase II dataset.

<p>Flavopiridol and flavo-G PK parameter estimates from the phase II study was evaluated for relationships with PGx. Presented are flavopiridol CL associations with ABCG2 rs2622624 (p = 0.008, Panel A) and rs3114018 (p = 0.004, Panel B); UGT1A1*28 (promoter) polymorphisms associated with flavo-G Cmax (p = 0.02, Panel C) and AUC (p = 0.04, Panel D); the ABCG2 rs2231142 SNP was weakly associated with flavopiridol AUC (Panel E, p = .08); For plots C and D, the x-axis indicates the number of promoter TA repeats for both gene copies (6.7 = 6 and 7 TA repeats; 7 = 7 TA repeats for each gene copy; 7.8 = 7 and 8 TA repeats; 8 = 8 TA repeats for each gene copy).</p