Synthesis and Preliminary Biological Assessment of Carborane-Loaded Theranostic Nanoparticles to Target Prostate-Specific Membrane Antigen.

Boron neutron capture therapy (BNCT) is an encouraging therapeutic modality for cancer treatment. Prostate-specific membrane antigen (PSMA) is a cell membrane protein that is abundantly overexpressed in prostate cancer and can be targeted with radioligand therapies to stimulate clinical responses in patients. In principle, a spatially targeted neutron beam together with specifically targeted PSMA ligands could enable prostate cancer-targeted BNCT. Thus, we developed and tested PSMA-targeted poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-b-PEG) nanoparticles (NPs) loaded with carborane and tethered to the radiometal chelator deferoxamine B (DFB) for simultaneous positron emission tomography (PET) imaging and selective delivery of boron to prostate cancer. Monomeric PLGA-b-PEGs were covalently functionalized with either DFB or the PSMA ligand ACUPA. Different nanoparticle formulations were generated by nanoemulsification of the corresponding unmodified and DFB- or ACUPA-modified monomers in varying percent fractions. The nanoparticles were efficiently labeled with 89Zr and were subjected to in vitro and in vivo evaluation. The optimized DFB(25)ACUPA(75) NPs exhibited strong in vitro binding to PSMA in direct binding and competition radioligand binding assays in PSMA(+) PC3-Pip cells. [89Zr]DFB(25) NPs and [89Zr]DFB(25)ACUPA(75) NPs were injected to mice with bilateral PSMA(-) PC3-Flu and PSMA(+) PC3-Pip dual xenografts. The NPs demonstrated twofold superior accumulation in PC3-Pip tumors to that of PC3-Flu tumors with a tumor/blood ratio of 25; however, no substantial effect of the ACUPA ligands was detected. Moreover, fast release of carborane from the NPs was observed, resulting in a low boron delivery to tumors in vivo. In summary, these data demonstrate the synthesis, characterization, and initial biological assessment of PSMA-targeted, carborane-loaded PLGA-b-PEG nanoparticles and establish the foundation for future efforts to enable their best use in vivo.

Residents-as-Teachers Curriculum for Radiation Oncology: A Targeted Needs Assessment.

PURPOSE: Achieving competency as educators is increasingly recognized as a critical part of residents' training in graduate medical education across specialties. In addition to teaching medical students, radiation oncology residents often play a vital role in peer and interprofessional education. We conducted a survey to identify the needs of radiation oncology residents for developing skills in teaching. METHODS AND MATERIALS: An anonymous, web-based survey was developed and distributed to resident physicians at US radiation oncology programs. Analyses describe respondent demographics, experiences with teaching, and interest in various aspects of a formal "residents-as-teachers" curriculum. RESULTS: There were 171 completed survey responses (27.5% response rate). A total of 146 residents (85.4%) reported receiving no formal training in teaching before residency, and 121 (70.8%) reported no formal training during residency. Residents who had formal training in teaching were significantly more likely to be "quite" or "extremely" confident about teaching compared with residents who had no prior formal training (76.0% vs 51.4%; P = .022). Residents most commonly taught other residents and medical students (163 [95.3%] and 160 [93.6%] respondents, respectively). The most common settings for teaching were one-on-one teaching (164 respondents [95.9%]), small-group lectures (135 respondents [78.9%]), and intradepartmental lectures (136 respondents [79.5%]). In response to open-ended questions regarding desired teaching opportunities and domains for teaching development, many residents expressed a lack of confidence in teaching and were interested in improvement across many aspects of teaching. CONCLUSIONS: Radiation oncology residents are expected and desire to teach in a multitude of settings across a wide variety of audiences. However, a significant proportion of radiation oncology residents lack formal training and rarely receive feedback for their teaching skills. The results of this national survey support the development of a residents-as-teachers curriculum for radiation oncology residents that would address the needs for and significant interest in this area.