Mukherjee, U. | Search bioRxiv

bioRxiv2022

Integrating pharmacogenomics data-driven prediction with bulk and single-cell RNAseq to demonstrate the efficacy of an NAMPT inhibitor against aggressive, taxane-resistant, and stem-like cells in lethal prostate cancer

Metastatic prostate cancer is the second leading cause of cancer deaths in US men. Resistance to standard medical castration and secondary taxane-based chemotherapy is nearly universal. Further, presence of cancer stem-like cells (EMT/epithelial to mesenchymal transdifferentiation) and neuroendocrine PCa (NEPC) subtypes significantly contribute to aggressive/advanced/lethal variants of PCa (AVPC). In this study, first we used single-cell RNA sequencing (scRNAseq) analysis to demonstrate that ARlow PCa cells in metastatic prostate cancer, including castration-sensitive tumors, harbored signatures of EMT, and cancer stemness. Next, we introduced a novel pharmacogenomics data-driven computational approach and identified several potential agents that can be re-purposed as novel secondary drugs ("secDrugs") to treat advance variants of Prostate cancer. Using scRNAseq as a biomarker-based drug screen, we demonstrated that a majority of the single-cell subclones in mCRPC and mCSPC cell lines also showed significantly high expression of the NAMPT pathway genes, indicating that the secDrug FK866, which targets NAMPT, is potentially effective against drug-resistant and stem-cell-like subpopulation cluster. Next, we showed significant in vitro cytotoxicity of FK866 as single-agent and in combination with the taxanes or Enzalutamide against models of clinically-advanced PCa. We performed bulk- and single-cell RNAseq to identify several pathways underlining FK866 mechanism of action and found that in addition to NAMPT inhibition, FK866 regulates tumor metastasis, cell migration, invasion, DNA repair machinery, redox homeostasis, autophagy, as well as cancer stemness-related genes HES1 and CD44. Further, we performed a microfluidic chip-based cell migration assay that demonstrated that FK866 reduces cancer cell invasion and motility, indicating abrogation of metastasis. Finally, using multiple PCa patient datasets, we showed that FK866 is potentially capable of reversing expression of several genes associated with biochemical recurrence and inter-ethnic differences, including IFITM3 and LTB4R. Thus, using FK866 as a proof-of-concept drug, we introduced a novel, universally applicable preclinical drug development pipeline to circumvent subclonal aggressiveness, drug resistance, and stemness in lethal PCa.

molecular biology↗

bioRxiv2021

Endoplasmic Reticulum Chaperone Genes Encode Effectors of Long-Term Memory

The mechanisms underlying memory loss associated with Alzheimers disease and related dementias (ADRD) remain unclear, and no effective treatments exist. Fundamental studies have shown that a set of transcriptional regulatory proteins of the nuclear receptor 4a (Nr4a) family serve as molecular switches for long-term memory. Here, we show that Nr4a proteins regulate the transcription of a group of genes encoding chaperones that localize to the endoplasmic reticulum (ER), which function to traffic plasticity-related proteins to the cell surface during long lasting forms of synaptic plasticity and memory. Nr4a transcription factors and ER chaperones are linked to ADRD in human samples as well as mouse models, and overexpressing Nr4a1 or the ER chaperone Hspa5 ameliorates the long-term memory deficits in a tau-based mouse model of ADRD, pointing towards novel therapeutic approaches for treating memory loss. Thus, our findings establish protein folding in the ER as a novel molecular concept underlying long-term memory, providing new insights into the mechanistic basis of cognitive deficits in dementia. One-Sentence SummaryMolecular approaches establish protein folding in the endoplasmic reticulum as a novel molecular concept underlying synaptic plasticity and memory, serving as a switch to regulate protein folding and trafficking, and driving cognitive deficits in neurodegenerative disorders.

neuroscience↗