Biobanks of fresh, unfixed human tissue represent a valuable source for gene expression analysis in translational research and molecular pathology. The aim of this study was to evaluate the impact of thawing on RNA integrity and gene expression in fresh frozen tissue specimens. Portions of snap frozen tonsil tissue, unfixed or immersed in RNAlater, were thawed at room temperature for 0 minute, 5 minutes, 30 minutes, 45 minutes, 1 hour, 3 hours, 6 hours, and 16 hours before RNA extraction. Additionally, tonsil tissue underwent repetitive freezing and thawing cycles. RNA integrity was analyzed by microchip gel electrophoresis and gene expression by quantitative real-time polymerase chain reaction for selected genes (FOS, TGFB1, HIF1A, BCL2, and PCNA). Minimal RNA degradation was detected after 30 minutes of thawing in unfixed samples. This degradation was accompanied by relevant changes in gene expression for FOS and BCL2 at 45 minutes. Modified primer design or the use of different housekeeping genes could not rectify the changes for FOS. Repetitive thawing cycles had similar effects on RNA integrity. The incubation of the tissue in RNAlater efficiently prevented RNA degradation. In conclusion, degradation of RNA in frozen tissue occurs first after several minutes of thawing. Already minimal decrease in RNA quality may result in significant changes in gene expression patterns in clinical tissue samples.
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http://dx.doi.org/10.1097/PDM.0b013e3181857e92 | DOI Listing |
Brief Bioinform
November 2024
Center for Artificial Intelligence Research, Wake Forest University School of Medicine, Winston-Salem, NC 27101, United States.
Pathway analysis plays a critical role in bioinformatics, enabling researchers to identify biological pathways associated with various conditions by analyzing gene expression data. However, the rise of large, multi-center datasets has highlighted limitations in traditional methods like Over-Representation Analysis (ORA) and Functional Class Scoring (FCS), which struggle with low signal-to-noise ratios (SNR) and large sample sizes. To tackle these challenges, we use a deep learning-based classification method, Gene PointNet, and a novel $P$-value computation approach leveraging the confusion matrix to address pathway analysis tasks.
View Article and Find Full Text PDFClin Cancer Res
January 2025
Stanford University, Palo Alto, CA, United States.
Purpose: After failing primary and secondary hormonal therapy, castration-resistant and neuroendocrine prostate cancer metastatic to the bone is invariably lethal, although treatment with docetaxel and carboplatin can modestly improve survival. Therefore, agents targeting biologically relevant pathways in PCa and potentially synergizing with docetaxel and carboplatin in inhibiting bone metastasis growth are urgently needed.
Experimental Design: Phosphorylated (activated) AXL expression in human prostate cancer bone metastases was assessed by immunohistochemical staining.
STAR Protoc
January 2025
Department of Statistics, University of Georgia, 310 Herty Drive, Athens, GA 30602, USA. Electronic address:
Spatial transcriptomics enhances our understanding of cellular organization by mapping gene expression data to precise tissue locations. Here, we present a protocol for using weighted ensemble method for spatial transcriptomics (WEST), which uses ensemble techniques to boost the robustness and accuracy of existing algorithms. We describe steps for preprocessing data, obtaining embeddings from individual algorithms, and ensemble integrating all embeddings as a similarity matrix.
View Article and Find Full Text PDFSci Transl Med
January 2025
Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
Sci Transl Med
January 2025
Graduate Program in Human Genetics, University of Miami Miller School of Medicine, 1501 NW 10th Avenue (M-860), Miami, FL 33136, USA.
Primary mitochondrial disorders are most often caused by deleterious mutations in the mitochondrial DNA (mtDNA). Here, we used a mitochondrial DddA-derived cytosine base editor (DdCBE) to introduce a compensatory edit in a mouse model that carries the pathological mutation in the mitochondrial transfer RNA (tRNA) alanine (mt-tRNA) gene. Because the original m.
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