Visualizing Borrelia burgdorferi Infection Using a Small-Molecule Imaging Probe.

In vivo diagnostic imaging of bacterial infections is currently reliant on targeting their metabolic pathways, an ineffective method to identify microbial species with low metabolic activity. Here, we establish HS-198 as a small-molecule fluorescent conjugate that selectively targets the highly conserved bacterial protein HtpG (high-temperature protein G), within Borrelia burgdorferi, the bacterium responsible for Lyme disease. We describe the use of HS-198 to target morphologic forms of B. burgdorferi in both the logarithmic growth phase and the metabolically dormant stationary phase as well as in inactivated spirochetes. Furthermore, in a murine infection model, systemically injected HS-198 identified B. burgdorferi as revealed by imaging in postnecropsy tissue sections. These findings demonstrate how small-molecule probes directed at conserved bacterial protein targets can function to identify the microbe using noninvasive imaging and potentially as scaffolds to deliver antimicrobial agents to the pathogen.

The Influential Role of BCL2 Family Members in Synovial Sarcomagenesis.

Synovial sarcomas are deadly soft tissue malignancies associated with t(X;18) balanced chromosomal translocations. Expression of the apoptotic regulator BCL2 is prominent in synovial sarcomas and has prompted the hypothesis that synovial sarcomagenesis may depend on it. Herein, it is demonstrated that Bcl2 overexpression enhances synovial sarcomagenesis in an animal model. Furthermore, we determined increased familial clustering of human synovial sarcoma patients with victims of other BCL2-associated malignancies in the Utah Population Database. Conditional genetic disruption of Bcl2 in mice also led to reduced sarcomagenesis. Pharmacologic inhibition specific to BCL2 had no demonstrable efficacy against human synovial sarcoma cell lines or mouse tumors. However, targeting BCLxL in human and mouse synovial sarcoma with the small molecule BH3 domain inhibitor, BXI-72, achieved significant cytoreduction and increased apoptotic signaling. Thus, the contributory role of BCL2 in synovial sarcomagenesis does not appear to render it as a therapeutic target, but mitochondrial antiapoptotic BCL2 family members may be.Implications: The association of BCL2 expression with synovial sarcoma is found to fit with a subtle, but significant, impact of its enhanced presence or absence during early tumorigenesis. However, specific pharmacologic inhibition of BCL2 does not demonstrate a persistent dependence in fully developed tumors. Conversely, inhibition of the BCL2 family member BCLxL resulted in nanomolar potency against human synovial sarcoma cell lines and 50% tumor reduction in a genetically engineered mouse model. Mol Cancer Res; 15(12); 1733-40. ©2017 AACR.

The Impact of Microenvironment on the Synovial Sarcoma Transcriptome.

Synovial sarcoma (SS) is initiated by a t(X;18) chromosomal translocation and resultant SS18-SSX fusion oncogene. Only a few SS cell lines exist. None has been compared to its source tumor. In order to compare matched tumor and cell line pairs, we performed RNAseq on 3 tumor/cell line pairs from a genetically engineered mouse model of SS, as well as 2 pairs from human SS tumors. Transcriptomes of mouse tumors and derivative cell lines deviated significantly. Differentially expressed genes highlighted inflammatory infiltrates and metabolism. The same was found for the human tumor and cell line pairs. More was shared between different tumors than between any tumor and its cell line. Direct xenografting generated transcriptomes that more closely resembled the primary tumor than did its derivative cell line. SS tumor transcriptomes are powerfully impacted by the environment wherein they reside, especially with regard to immune interaction and metabolism.