Preclinical assessment of MAGMAS inhibitor as a potential therapy for pediatric medulloblastoma

Medulloblastoma, the most common pediatric brain malignancy, has Sonic Hedgehog (SHH) and non-SHH group3 subtypes. MAGMAS (Mitochondrial Associated Granulocyte Macrophage colony-stimulating factor Signaling molecules) encode for mitochondrial import inner membrane translocase subunit and is responsible for translocation of matrix proteins across the inner membrane. We previously reported that a small molecule MAGMAS inhibitor, BT9, decreases cell proliferation, migration, and oxidative phosphorylation in adult glioblastoma cell lines. The aim of our study was to investigate whether the chemotherapeutic effect of BT9 can be extended to pediatric medulloblastoma.

Methods

Multiple in vitro assays were performed using human DAOY (SHH activated tp53 mutant) and D425 (non-SHH group 3) cells. The impact of BT9 on cellular growth, death, migration, invasion, and metabolic activity were quantified using MTT assay, TUNEL staining, scratch wound assay, Matrigel invasion chambers, and seahorse assay, respectively. Survival following 50mg/kg BT9 treatment was assessed in vivo in immunodeficient mice intracranially implanted with D425 cells.

Results

Compared to control, BT9 treatment led to a significant reduction in medulloblastoma cell growth (DAOY, 24hrs IC50: 3.6uM, 48hrs IC50: 2.3uM, 72hrs IC50: 2.1uM; D425 24hrs IC50: 3.4uM, 48hrs IC50: 2.2uM, 72hrs IC50: 2.1uM) and a significant increase in cell death (DAOY, 24hrs p=0.0004, 48hrs p<0.0001; D425, 24hrs p=0.0001, 48hrs p=0.02). In DAOY cells, 3uM BT9 delayed migration, and significantly decreased DAOY and D425 cells invasion (p < 0.0001). Our in vivo study, however, did not extend survival in xenograft mouse model of group3 medulloblastoma compared to vehicle-treated controls.

Conclusions

Our in vitro data showed BT9 antitumor efficacy in DAOY and D425 cell lines suggesting that BT9 may represent a promising targeted therapeutic in pediatric medulloblastoma. These data, however, need to be further validated in animal models.

Identification of new hit to lead magmas inhibitors as potential therapeutics for glioblastoma

In continuation of our previous efforts for the development of potent small molecules against brain cancer, herein we synthesized seventeen new compounds and tested their anti-gliomapotential against established glioblastoma cell lines, namely, D54MG, U251, and LN-229 as well as patient derived cell lines (DB70 and DB93). Among them, the carboxamide derivatives, BT-851 and BT-892 were found to be the most active leads in comparison to our established hit compound BT#9.The SAR studies of our hit BT#9 compound resulted in the development of two new lead compounds by hit to lead strategy. The detailed biological studies are currently underway. The active compounds could possibly act as template for the future development of newer anti-glioma agents.

Medical student exam performance and perceptions of a COVID-19 pandemic-appropriate pre-clerkship medical physiology and pathophysiology curriculum

BACKGROUND

Medical schools were compelled to abruptly transition pre-clerkship curricula to remote learning formats due to the emergence of the Coronavirus Disease 2019 (COVID-19) pandemic. We evaluated student perceptions of remote learning, exam performance, and utilization of third-party learning resources to assess the implementation of a newly developed pandemic-appropriate physiology curriculum.

METHODS

This was an observational study based on a survey conducted in the Spring of 2021 at the University of California, Irvine, School of Medicine (UCISOM). This study aimed to assess first (MS1) and second year (MS2) medical students' perceptions of satisfaction, support, academic performance, and connectedness before and during the COVID-19 pandemic. The MS1 class began medical school during the first year of the COVID-19 pandemic, whereas the MS2 class did so prior to the start of the pandemic. A survey instrument was developed and validated to identify the impact remote learning had on student self-perceptions of the Medical Physiology and Pathophysiology course. Surveys were distributed to all students and responses were collected on a voluntary basis. Exam scores on a customized National Board of Medical Examiners (NBME) physiology shelf exam were also compared to objectively identify how the remote curriculum during the pandemic impacted academic performance.

RESULTS

Of 204 students enrolled, 74 responses were analyzed, with 42 MS1 (40% of MS1s) and 32 MS2 (31% of MS2s) responses. Overall, MS1s and MS2s were satisfied with the curriculum they received (95 and 97% respectively) and the school's support of their concerns (86 and 100% respectively). Notably, only 50% of MS1s felt connected to their peers, compared to 94% of MS2s. Lecture attendance and self-perception of their academic performance were similar between both classes. Interestingly, the intra-pandemic class's NBME exam average in 2020 (60.2% ± 8.9, n = 104) was significantly higher than the pre-pandemic class average in 2019 (56.8% ± 11.3, n = 100). Both classes primarily used course materials over third-party learning resources. An additional set of survey questions distributed only to the MS1 class found that the majority of MS1s reported minimal barriers with regards to accessibility, including internet connectivity, study-conducive environments, and balancing family commitments. Overall, pre-clerkship medical students had positive perceptions of the newly developed pandemic-appropriate physiology curriculum.

CONCLUSIONS

Changes to the pre-clerkship physiology curriculum during the COVID-19 pandemic were met with overall satisfaction from the students and an increase in NBME scores. More attention to student connectedness is needed to improve how remote learning can be best optimized into future curricula development.

Freshly Thawed Cryobanked Human Neural Stem Cells Engraft within Endogenous Neurogenic Niches and Restore Cognitive Function after Chronic Traumatic Brain Injury

Human neural stem cells (hNSCs) have potential as a cell therapy after traumatic brain injury (TBI). While various studies have demonstrated the efficacy of NSCs from ongoing culture, there is a significant gap in our understanding of freshly thawed cells from cryobanked stocks-a more clinically relevant source. To address these shortfalls, the therapeutic potential of our previously validated Shef-6.0 human embryonic stem cell (hESC)-derived hNSC line was tested after long-term cryostorage and thawing before transplant. Immunodeficient athymic nude rats received a moderate unilateral controlled cortical impact (CCI) injury. At four weeks post-injury, 6 × 105 freshly thawed hNSCs were transplanted into six injection sites (two ipsi- and four contra-lateral) with 53.4% of cells surviving three months post-transplant. Interestingly, most hNSCs were engrafted in the meninges and the lining of lateral ventricles, associated with high CXCR4 expression and a chemotactic response to SDF1alpha (CXCL12). While some expressed markers of neuron, astrocyte, and oligodendrocyte lineages, the majority remained progenitors, identified through doublecortin expression (78.1%). Importantly, transplantation resulted in improved spatial learning and memory in Morris water maze navigation and reduced risk taking in an elevated plus maze. Investigating potential mechanisms of action, we identified an increase in ipsilateral host hippocampus cornu ammonis (CA) neuron survival, contralateral dentate gyrus (DG) volume, and DG neural progenitor morphology as well as a reduction in neuroinflammation. Together, these findings validate the potential of hNSCs to improve function after TBI and demonstrate that long-term biobanking of cells and thawing aliquots before use may be suitable for clinical deployment.

Transforming University of California, Irvine medical physiology instruction into the pandemic era

At the University of California, Irvine, School of Medicine (UCISOM), the COVID-19 pandemic is accelerating the transition of face-to-face didactic lectures to online platforms. Institutions nationwide have opted to transition their lectures into remote instruction for the upcoming Fall 2020 academic year. UCISOM's pre-clerkship Medical Immunology course in the Spring 2020 serves as a template for other medical courses to successfully transform lecture content into virtual presentations. To help facilitate successful large-scale transition to online courses, UCI developed institutional support and implemented a Division of Teaching Excellence and Innovation (DTEI) Fellowship and iMedEd programs to support medical educators throughout Summer. Previously developed E-learning modules for renal and acid-base physiology serve as the foundation for novel pulmonary E-learning modules at UCISOM. In preparation for the new academic year, in a collaboration between faculty, UCISOM's top performing second-year medical students (MS2s) and DTEI fellows worked together during the summer to transition UCISOM's Medical Physiology and Pathophysiology course online. With over 100 first-year medical students attending the Medical Physiology course over live synchronous Zoom instruction, formative and summative assessments were incorporated into Canvas modules along with peer-led review sessions and new E-learning modules to educate and monitor student progress. The course will maintain existing in-person active learning activities for students to get hands-on experience using the latest medical devices while maintaining social distancing. Successful transition to online medical education at UCISOM will depend on increasing use of formative assessments, increased utilization of peer-led review sessions, and efficient communication to help foster self-directed learning.