Serum miRNAs are differentially expressed between patients with early-stage NSCLC and controls. The utility of miR-1254 and miR-574-5p serum-based biomarkers as minimally invasive screening and triage tools for subsequent diagnostic evaluation warrants additional validation.

Brain metastasis (BM) can affect ~25% of non-small cell lung cancer (NSCLC) patients during their lifetime. Efforts to characterize patients that will develop BM have been disappointing. microRNAs (miRNAs) regulate the expression of target mRNAs. miRNAs play a role in regulating a variety of targets and, consequently, multiple pathways, which make them a powerful tool for early detection of disease, risk assessment, and prognosis. We investigated miRNAs that may serve as biomarkers to differentiate between NSCLC patients with and without BM. miRNA microarray profiling was performed on samples from clinically matched NSCLC from seven patients with BM (BM+) and six without BM (BM−). Using t-test and further qRT-PCR validation, eight miRNAs were confirmed to be significantly differentially-expressed. Of these, expression of miR-328 and miR-330-3p were able to correctly classify BM+ vs. BM− patients. This classifier was used on a validation cohort (n=15) and it correctly classified 12/15 patients. Gene expression analysis comparing A549 parental and A549 cells stably transfected to over-express miR-328 (A549–328) identified several significantly differentially-expressed genes. PRKCA was one of the genes over-expressed in A549–328 cells. Additionally, A549–328 cells had significantly increased cell migration compared to A549 cells, which was significantly reduced upon PRKCA knockdown. In summary, miR-328 has a role in conferring migratory potential to NSCLC cells working in part through PRKCA and with further corroboration in additional independent cohorts, these miRNAs may be incorporated into clinical treatment decision making to stratify NSCLC patients at higher risk for developing BM.

The spindle checkpoint prevents activation of the anaphase-promoting complex (APC/C) until all chromosomes are correctly attached to the mitotic spindle. Early in mitosis, the mitotic checkpoint complex (MCC) inactivates the APC/C by binding the APC/C activating protein CDC20 until the chromosomes are properly aligned and attached to the mitotic spindle, at which point MCC disassembly releases CDC20 to activate the APC/C. Once the APC/C is activated, it targets cyclin B and securin for degradation, and the cell progresses into anaphase. While phosphorylation is known to drive many of the events during the checkpoint, the precise molecular mechanisms regulating spindle checkpoint maintenance and inactivation are still poorly understood. We sought to determine the role of mitotic phosphatases during the spindle checkpoint. To address this question, we treated spindle checkpointarrested cells with various phosphatase inhibitors and examined the effect on the MCC and APC/C activation. Using this approach we found that 2 phosphatase inhibitors, calyculin A and okadaic acid (1 mM), caused MCC dissociation and APC/C activation leading to cyclin A and B degradation in spindle checkpoint-arrested cells. Although the cells were able to degrade cyclin B, they did not exit mitosis as evidenced by high levels of Cdk1 substrate phosphorylation and chromosome condensation. Our results provide the first evidence that phosphatases are essential for maintenance of the MCC during operation of the spindle checkpoint.

Availability of trained professionals to assist researchers navigating regulatory pathways for new drug and device development is limited within academic institutions. We created ReGARDD (Regulatory Guidance for Academic Research of Drugs and Devices), a regional forum initially involving regulatory professionals from four Clinical and Translational Science Award (CTSA)-funded institutions, to build and capitalize on local expertise and to develop a regulatory guidance website geared toward academic researchers. Since 2015, members organized 15 forums covering topics such as FDA premarket submissions, gene therapy, and intellectual property for devices and therapeutics. Through user feedback, targeted surveys, and ongoing iterative processes, we refined and maintained a shared regulatory website, which reached 6000þ users in 2019. Website updates improved navigation to drug versus device topic areas, provided new educational content and videos to address commonly asked questions, and created a portal for posting upcoming training opportunities. Survey respondents rated the website favorably and endorsed expanding ReGARDD as a centralized resource. ReGARDD strengthened the regional regulatory workforce, increased regulatory efficiency, and promulgated best organizational and operational practices. Broad-scale deployment of the ReGARDD model across the CTSA consortium may facilitate the creation of a network of regional forums and reduce gaps in access to regulatory support.

The spindle assembly checkpoint (SAC) prevents activation of the anaphase-promoting complex (APC/C) until all chromosomes are correctly attached to the mitotic spindle. A defective SAC contributes to errors in chromosome segregation, which promotes aneuploidy and may eventually lead to cancer. Early in mitosis, the mitotic checkpoint complex (MCC) inactivates the APC/C by binding the APC/C activating protein cdc20 until the chromosomes are properly aligned, at which point the MCC dissociates and releases cdc20 to activate the APC/C. Once the APC/C is activated, it targets many substrates for degradation, including cyclin B and securin, and the cell progresses into anaphase. The precise molecular mechanisms regulating SAC inactivation are still poorly understood. We sought to determine the role of mitotic phosphatases in the SAC. To address this question, we treated mitotic cells with various phosphatase inhibitors to examine their effect on APC/C activation. Using this approach we identified two inhibitors, calyculin A and okadaic acid (1uM), that cause MCC dissociation and APC/C activation leading to cyclin A and cyclin B degradation in nocodazole-arrested cells. Although the cells are able to degrade cyclin B, they do not exit mitosis as evidenced by high levels of cdk1 substrate phosphorylation and chromosome condensation. Our results demonstrate that a calyculin A and okadaic acid (1uM) sensitive phosphatase is required for SAC activation. Citation Format: Kristen Foss, Liguo Zhang, Alexander C. Robeson, Sally Kornbluth. The spindle assembly checkpoint requires phosphatase activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3770. doi:10.1158/1538-7445.AM2015-3770