Steve A Kay

Climate change is a global concern for all life on our planet, including humans and plants. Plants’ growth and development are significantly affected by abiotic stresses, including adverse temperature, inadequate or excess water availability, nutrient deficiency, and salinity. The circadian clock is a master regulator of numerous developmental and metabolic processes in plants. In an effort to identify new clock-related genes and outputs through bioinformatic analysis, we have revealed that CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) play a crucial role in regulating a wide range of abiotic stress responses and target ABSCISIC ACID RESPONSIVE ELEMENTS-BINDING FACTOR3 (ABF3), a key transcription factor in the plant hormone Abscisic acid (ABA)-signaling pathway. Specifically, we found that CCA1 and LHY regulate the expression of ABF3 under diel conditions …

Collegiate athletes must satisfy the academic obligations common to all undergraduates, but they have the additional structural and social stressors of extensive practice time, competition schedules, and frequent travel away from their home campus. Clearly such stressors can have negative impacts on both their academic and athletic performances as well as on their health. These concerns are made more acute by recent proposals and decisions to reorganize major collegiate athletic conferences. These rearrangements will require more multi-day travel that interferes with the academic work and personal schedules of athletes. Of particular concern is additional east-west travel that results in circadian rhythm disruptions commonly called jet lag that contribute to the loss of amount as well as quality of sleep. Circadian misalignment and sleep deprivation and/or sleep disturbances have profound effects on physical …

Circadian clock genes are emerging targets in many types of cancer, but their mechanistic contributions to tumor progression are still largely unknown. This makes it challenging to stratify patient populations and develop corresponding treatments. In this work, we show that in breast cancer, the disrupted expression of circadian genes has the potential to serve as biomarkers. We also show that the master circadian transcription factors (TFs) BMAL1 and CLOCK are required for the proliferation of metastatic mesenchymal stem-like (mMSL) triple-negative breast cancer (TNBC) cells. Using currently available small molecule modulators, we found that a stabilizer of cryptochrome 2 (CRY2), the direct repressor of BMAL1 and CLOCK transcriptional activity, synergizes with inhibitors of proteasome, which is required for BMAL1 and CLOCK function, to repress a transcriptional program comprising circadian cycling genes in mMSL TNBC cells. Omics analyses on drug-treated cells implied that this repression of transcription is mediated by the transcription factor binding sites (TFBSs) features in the cis-regulatory elements (CRE) of clock-controlled genes. Through a massive parallel reporter assay, we defined a set of CRE features that are potentially repressed by the specific drug combination. The identification of cis-element enrichment may serve as a new way of defining and targeting tumor types through the modulation of cis-regulatory programs, and ultimately provide a new paradigm of therapy design for cancer types with unclear drivers like TNBC.

Anti VEGF A antibody Bevacizumab combined with standard chemotherapy has improved outcomes for CRC patients. However, a subset of CRC patients acquires resistance to anti-VEGF treatment and underlying mechanism is poorly understood. Our recent study reported that circadian clock transcription factor BMAL1 drives transcription of VEGFA conferring resistance to bevacizumab treatment. Our rational is to stabilize negative regulator of circadian clock CRY protein to inhibit BMAL1 activity in a negative feedback loop. In this study, we evaluated whether CRY stabilizers SHP656 and SHP1705 in combination with bevacizumab can synergistically enhance anti-tumor effect in CRC mouse models. Methods: In vitro tube formation assay was performed with HUVECs cells to investigate the effect of CRY stabilizer on tube formation. For in vivo experiments, 106 HCT116 human CRC cells were injected …

Despite the extensive efforts of researchers and physicians over the past two decades, glioblastoma (GBM) remains the most prevalent brain tumor type with a grim average survival time of 8 months following diagnosis irrespective of treatment. Additionally, the current standard-of-care has not changed from maximal surgical resection followed by concurrent chemoradiation from its establishment in 2005. One of the major challenges that limits progress in treating GBM is the presence of GBM stem cells (GSCs) that are highly invasive, reaching far past the tumor margins, are resistant to both chemotherapy and radiation, and can recapitulate the primary tumor following resection. Recent studies have found that GSCs, however, are highly sensitive to targeting of core circadian clock components, particularly positive regulators of the clock Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output …

Pharmacological Strategies to Target Circadian Clock Genes in TNBC Yuanzhong Pan, Priya Jayachandran, Evanthia T. Roussos Torres, Steve A. Kay Background: Triple-negative breast cancer (TNBC) remains the most aggressive form of breast cancer and more targeted treatment options remain challenging. Our recent analysis of clinical data showed that circadian clock genes (including positive regulators BMAL1 and CLOCK, and negative regulators CRYs, PERs, and REV-ERBs) play important roles in breast cancer, and most prominently in TNBC. We have also shown in other cancer types that cells with a mesenchymal signature and stem-cell like state rely on BMAL1/CLOCK activity to support proliferation. BMAL1 and CLOCK are transcription factors that have remained “undruggable” to date. Alternatively, our lab developed small molecule compounds that target the negative regulators CRY, REV-ERB and …

Transcription factors (TFs) are key regulators of homeostasis and cancer. Recent advances in pharmacological targeting of TFs makes them valuable targets in various diseases, but systems-level understanding of the function and regulation of TFs from different families in cancers remains lacking. Our lab and collaborators have been developing new small molecules to modulate the functions of key regulators of the circadian clock BMAL1 and CLOCK, which are bHLH family TFs that activate gene expression by binding to a DNA motif called E-box, with a consensus sequence of CANNTG. E-boxes are ubiquitous in the genome and broadly regulate essential physiological processes of the cell, but their molecular biology in cancer is largely unknown. In the current work we tested the ability of small molecules to regulate the expression of BMAL1 and CLOCK target genes. Across different cell lines of various cancer …

Background: Disruption of circadian processes has been linked to cancer initiation, progression, metastasis, resistance, and mortality. Clock proteins are an emerging target for therapy in breast cancer. Circadian rhythms are controlled by a network of transcription/translation feedback loops primarily driven by BMAL and CLOCK and the transcriptional repressors period (PER1-3) and cryptochrome (CRY1-2). We investigated the molecular and clinical associations of clock genes in breast cancer. Methods: A total of 9563 breast tumors underwent molecular profiling (Caris Life Sciences). Analyses included next-generation sequencing of DNA (592 genes-NextSeq, WES-NovaSeq) and RNA (NovaSeq). Clock gene Score (CS) was determined using expression of clock pathway gene Z scores (positives of BMAL, CLOCK and negatives of PER1/2 and CRY1/2) and then stratified into quartiles. xCell was used to quantify …