Rhesus Theta Defensin 1 Promotes Long Term Survival in Systemic Candidiasis by Host Directed Mechanisms.

Invasive candidiasis is an increasingly frequent cause of serious and often fatal infections in hospitalized and immunosuppressed patients. Mortality rates associated with these infections have risen sharply due to the emergence of multidrug resistant (MDR) strains of C. albicans and other Candida spp., highlighting the urgent need of new antifungal therapies. Rhesus theta (θ) defensin-1 (RTD-1), a natural macrocyclic antimicrobial peptide, was recently shown to be rapidly fungicidal against clinical isolates of MDR C. albicans in vitro. Here we found that RTD-1 was rapidly fungicidal against blastospores of fluconazole/caspofungin resistant C. albicans strains, and was active against established C. albicans biofilms in vitro. In vivo, systemic administration of RTD-1, initiated at the time of infection or 24 h post-infection, promoted long term survival in candidemic mice whether infected with drug-sensitive or MDR strains of C. albicans. RTD-1 induced an early (4 h post treatment) increase in neutrophils in naive and infected mice. In vivo efficacy was associated with fungal clearance, restoration of dysregulated inflammatory cytokines including TNF-α, IL-1ß, IL-6, IL-10, and IL-17, and homeostatic reduction in numbers of circulating neutrophils and monocytes. Because these effects occurred using peptide doses that produced maximal plasma concentrations (Cmax) of less than 1% of RTD-1 levels required for in vitro antifungal activity in 50% mouse serum, while inducing a transient neutrophilia, we suggest that RTD-1 mediates its antifungal effects in vivo by host directed mechanisms rather than direct fungicidal activity. Results of this study suggest that θ-defensins represent a new class of host-directed compounds for treatment of disseminated candidiasis.

Establishment of a platform of non-small-cell lung cancer patient-derived xenografts with clinical and genomic annotation.

BACKGROUND: Preclinical models that can better predict therapeutic activity in clinical trials are needed in this era of personalized cancer treatment. Herein, we established genomically and clinically annotated patient-derived xenografts (PDXs) from non-small-cell lung cancer (NSCLC) patients and investigated whether these PDXs would faithfully recapitulate patient responses to targeted therapy. METHODS: Patient-derived tumors were implanted in immunodeficient mice and subsequently expanded via re-implantation. Established PDXs were examined by light microscopy, genomic profiling, and in vivo drug testing, and the successful engraft rate was analyzed with the mutation profile, histology, or acquisition method. Finally, the drug responses of PDXs were compared with the clinical responses of the respective patients. RESULTS: Using samples from 122 patients, we established 41 NSCLC PDXs [30 adenocarcinoma (AD), 11 squamous cell carcinoma (SQ)], among which the following driver mutation were observed: 13 EGFR-mutant, 4 ALK-rearrangement, 1 ROS1-rearrangement, 1 PIK3CA-mutant, 1 FGFR1-amplification, and 2 KRAS-mutant. We rigorously characterized the relationship of clinical features to engraftment rate and latency rates. The engraft rates were comparable across histologic type. The AD engraft rate tended to be higher for surgically resected tissues relative to biopsies, whereas similar engraft rates was observed for SQ, irrespective of the acquisition method. Notably, EGFR-mutants demonstrated significantly longer latency time than EGFR-WT (86 vs. 37days, P = 0.007). The clinical responses were recapitulated by PDXs harboring driver gene alteration (EGFR, ALK, ROS1, or FGFR1) which regressed to their target inhibitors, suggesting that established PDXs comprise a clinically relevant platform. CONCLUSION: The establishment of genetically and clinically annotated NSCLC PDXs can yield a robust preclinical tool for biomarker, therapeutic target, and drug discovery.