Applications in RNA analysis

Terminal modifications independent cell-free RNA sequencing enables sensitive early cancer detection and classification. Jun Wang, Jinyong Huang, Yunlong Hu, et al. Nature Communications   15, Article number: 156 (2024) 

(Note: Apostle MiniMax technology is used in this study.) 

Abstract Cell-free RNAs (cfRNAs) offer an opportunity to detect diseases from a transcriptomic perspective, however, existing techniques have fallen short in generating a comprehensive cell-free transcriptome profile. We develop a sensitive library preparation method that is robust down to 100 µl input plasma to analyze cfRNAs independent of their 5’-end modifications. We show that it outperforms adapter ligation-based method in detecting a greater number of cfRNA species. We perform transcriptome-wide characterizations in 165 lung cancer, 30 breast cancer, 37 colorectal cancer, 55 gastric cancer, 15 liver cancer, and 133 cancer-free participants and demonstrate its ability to identify transcriptomic changes occurring in early-stage tumors. We also leverage machine learning analyses on the differentially expressed cfRNA signatures and reveal their robust performance in cancer detection and classification. Our work sets the stage for in-depth study of the cfRNA repertoire and highlights the value of cfRNAs as cancer biomarkers in clinical applications.

(Methods section)  cfRNA extraction

Frozen plasma samples were thawed on ice prior to cfRNA extraction. 200 μl of plasma samples were subjected to cfRNA extraction using the Apostle MiniMax High-Efficiency cfRNA Isolation Kit (Apostle), following the manufacturer’s protocol with minor modifications.

Comprehensive characterization of small noncoding RNA profiles in hypoxia-induced pulmonary hypertension (HPH) rat tissues. Jun Wang,  Jiahao Kuang, Shasha Zhang, et al. iScience 2024 Feb 16; 27(2): 108815.

(Note: Apostle MiniMax technology is used in this study.) 

Abstract 

Hypoxia-induced pulmonary hypertension (HPH) is a fatal cardiovascular disease characterized by an elevation in pulmonary artery pressure, resulting in right ventricular dysfunction and eventual heart failure. Exploring the pathogenesis of HPH is crucial, and small noncoding RNAs (sncRNAs) are gaining recognition as potential regulators of cellular responses to hypoxia. In this study, we conducted a comprehensive analysis of sncRNA profiles in eight tissues of male HPH rats using high-throughput sequencing. Our study unveiled several sncRNAs, with the brain, kidney, and spleen exhibiting the highest abundance of microRNA (miRNA), tRNA-derived small RNA (tDR), and small nucleolar RNA (snoRNA), respectively. Moreover, we identified numerous tissue-specific and hypoxia-responsive sncRNAs, particularly miRNAs and tDRs. Interestingly, we observed arm switching in miRNAs under hypoxic conditions and a significant increase in the abundance of 5′ tRNA-halves among the total tDRs during hypoxia. Overall, our study provides a comprehensive characterization of the sncRNA profiles in HPH rats.

Methods Section

sncRNA sequencing library preparation 

To isolate total RNA from the eight different tissues and plasma, we used RNAiso Plus (Takara, Japan) and Apostle MiniMax High Efficiency cfRNA Isolation Kit (Apostle) according to the manufacturer’s instructions.

Liquid Biopsy for Evaluating Mutations and Chromosomal Aberrations in Cerebrospinal Fluid from Patients with Primary or Metastatic Central Tumors. Ahmad Charifa, Sally Agersborg,  Arash Mohtashamian, Andrew Ip, Andre Goy, Maher Albitar, The Journal of Liquid Biopsy (2024), https://doi.org/10.1016/j.jlb.2024.100281

(Note: Apostle MiniMax technology is used in this study.) 

Abstract 

Background

Cytopathology analysis of cerebrospinal fluid (CSF) is limited in detecting tumors in patients with suspected primary or metastatic central nervous system (CNS) malignancy. We investigated the use of CSF liquid biopsy (LBx) to detect neoplastic processes in the CNS. Methods: Cell-free DNA (cfDNA) from the CSF of patients with suspected metastatic (N=106) or primary CNS (N=23) tumors was deep sequenced using a 302-gene panel.

Results

Four samples (3%) (3 metastatic and 1 primary) failed sequencing quality control criteria. Metastatic tumor was confirmed in 84 (82%) of the 103 patients suspected of metastatic tumor. Primary CNS tumor was confirmed in 11 of 22 (50%) patients suspected of CNS tumor. Chromosomal abnormalities were detected in 55 samples (54%). Germline mutations were detected in 23 (22%) patients with metastatic tumors and in 1 (5%) with a primary CNS tumor. Of the 29 patients with metastatic breast cancers, 2 (7%) had mutations in ESR1 and 9 (31%) had mutations in PIK3CA. Of the 21 patients with metastatic lung cancer, 9 (43%) had EGFR mutations and 5 (24%) had KRAS mutations. Upon comparing CSF LBx with peripheral blood LBx in 14 patients, 13 (93%) showed only CHIP and one patient showed CNS primary tumor mutation. Serial samples from 14 patients demonstrate that CSF LBx can be used for monitoring therapy efficacy.

Conclusions

LBx using CSF is clinically reliable and provides informative results in a substantial proportion of patients with metastatic CNS tumors and to a lesser degree in patients with primary CNS tumors.

(Materials and Methods section)

cfDNA and cfRNA Extraction

We used the Apostle MiniMax High-Efficiency total nucleic acid isolation Kit (Beckman Coulter, Brea, CA, USA) and followed the protocol recommended by the manufacturer as previously described in detail. After extraction, half of the cell-free total nucleic acid was treated with DNase to obtain cfRNA, and the other half was used for cfDNA analysis.

Combining cell-free RNA with cell-free DNA in liquid biopsy for hematologic and solid tumors. Maher Albitar, Hong Zhang, Ahmad Charifa, et al. Heliyon  9 (2023) e16261; May 16, 2023 

(Note: Apostle MiniMax technology is used in this study.) 

Abstract Current use of liquid biopsy is based on cell-free DNA (cfDNA) and the evaluation of mutations or methylation pattern. However, expressed RNA can capture mutations, changes in expression levels due to methylation, and provide information on cell of origin, growth, and proliferation status. We developed an approach to isolate cell-free total nucleic acid (cfDNA) and used targeted next generation sequencing to sequence cell-free RNA (cfRNA) and cfDNA as new approach in liquid biopsy. We demonstrate that cfRNA is overall more sensitive than cfDNA in detecting mutations. We show that cfRNA is reliable in detecting fusion genes and cfDNA is reliable in detecting chromosomal gains and losses. cfRNA levels of various solid tumor biomarkers were significantly higher (P < 0.0001) in samples from solid tumors as compared with normal control. Similarly, cfRNA lymphoid markers and cfRNA myeloid markers were all higher in lymphoid and myeloid neoplasms, respectively as compared with control (P < 0.0001). Using machine learning we demonstrate cfRNA was highly predictive of diagnosis (AUC >0.98) of solid tumors, B-cell lymphoid neoplasms, T-cell lymphoid neoplasms, and myeloid neoplasms. In evaluating the host immune system, cfRNA CD4:CD8B and CD3D:CD19 ratios in normal controls were as expected (median: 5.92 and 6.87, respectively) and were significantly lower in solid tumors (P < 0.0002). This data suggests that liquid biopsy combining analysis of cfRNA with cfDNA is practical and may provide helpful information in predicting genomic abnormalities, diagnosis of neoplasms and evaluating both the tumor biology and the host response.

(Methods section)  We used Apostle MiniMax High Efficiency cfRNA/cfDNA isolation kit and followed the recommended protocol. After extraction, half of the cfDNA was treated with DNase to obtain cfRNA and the other half was used for DNA studies.