Good Quality RNA Research Articles

Methods to Enable Spatial Transcriptomics of Bone Tissues.

Understanding the relationship between the cells and their location within each tissue is critical to uncover the biological processes associated with normal development and disease pathology. Spatial transcriptomics is a powerful method that enables the analysis of the whole transcriptome within tissue samples, thus providing information about the cellular gene expression and the histological context in which the cells reside. While this method has been extensively utilized for many soft tissues, its application for the analyses of hard tissues such as bone has been challenging. The major challenge resides in the inability to preserve good quality RNA and tissue morphology while processing the hard tissue samples for sectioning. Therefore, a method is described here to process freshly obtained bone tissue samples to effectively generate spatial transcriptomics data. The method allows for the decalcification of the samples, granting successful tissue sections with preserved morphological details while avoiding RNA degradation. In addition, detailed guidelines are provided for samples that were previously paraffin-embedded, without demineralization, such assamples collected from tissue banks. Using these guidelines, high-quality spatial transcriptomics data generated from tissue bank samples of primary tumor and lung metastasis of bone osteosarcoma are shown.

Standardisation of an efficient RNA isolation protocol from the seeds of Momordica charantia var. muricata (Willd.): A Comparative Evaluation

Extraction of high-quality total RNA from Momordica charantia var. muricata seeds is difficult due to the presence of polyphenolic and polysaccharide compounds which bind to nucleic acids and thus they co-precipitate and contaminate the RNA samples. The current study aimed to find out a reliable and reproducible RNA extraction method for obtaining good-quality RNA from the seeds of Momordica charantia var. muricata (Willd). The RNA was isolated from seed tissues with four different extraction protocols including the cetyltrimethylammonium bromide (CTAB) method, TRIzol (Invitrogen) method, GenElute™ total RNA purification kit (Sigma-Aldrich) and Plant RNeasy mini kit (Qiagen). The Qiagen RNeasy plant mini kit was the most efficient extraction method providing the highest RNA yield and good quality. The method successfully enhanced the yield of RNA to 923.27 ± 58.64 ng/μl and electrophoresis revealed two distinct bright 28S and 18S rRNA bands and spectrophotometric quantification detected A260/ A280 ratio of 2.04±0.01 within the desired range of 1.8-2. To verify that the RNA quality obtained was appropriate for downstream molecular applications, the isolated RNA samples were converted into cDNA and PCR amplification of the cDNA was performed using a housekeeping gene (Actin 7) and a dormancy-specific gene (DOG1). The current investigation reports on a method for isolating high-quality RNA from M. charantia var. muricata seeds for future dormancy gene expression studies.

Comparison of three different RNA extraction kits for transcriptome analysis of Indonesian rice (Oryza sativa L) explant for anther culture

Recalcitrancy is the main problem in rice anther culture, especially in an Indica subspecies. It is well known that recalcitrancy is genotype dependent, and the effort to tackle this problem is mostly in the manipulations of media. Uncovering the genes responsible for recalcitrancy will benefit to enhance the success of this technique to accelerate the breeding process of Indonesian rice varieties which mostly belong to the indica subspecies. RNA-Seq is considered one of the best approaches to finding candidate genes responsible for specific traits including recalcitrant in anther culture. The aim of this study was to obtain the high concentration and good quality of RNA extracted methods using various extraction kits. The RNA extraction was carried out using Tripure, Promega, and RibospinTM Plant (Geneall) kit methods. Quality of RNA provided by the Promega kit showed good quality of RNA in all three genotypes tested ranging from 2.06±0.01-2.11±0.00 for A260/280 and 1.86±0.14-1.95±0.10 for A260/230.

DNA-free high-quality RNA extraction from 39 difficult-to-extract plant species (representing seasonal tissues and tissue types) of 32 families, and its validation for downstream molecular applications

BackgroundHigh-purity RNA serves as the basic requirement for downstream molecular analysis of plant species, especially the differential expression of genes to various biotic and abiotic stimuli. But, the extraction of high-quality RNA is usually difficult from plants rich in polysaccharides and polyphenols, and their presence usually interferes with the downstream applications. The aim of the study is to optimize the extraction of high-quality RNA from diverse plant species/tissues useful for downstream molecular applications.ResultsExtraction of RNA using commercially available RNA extraction kits and routine hexadecyltrimethylammonium bromide (CTAB) methods did not yield good quality DNA-free RNA from Prosopis cineraria, Conocarpus erectus, and Phoenix dactylifera. A reliable protocol for the extraction of high-quality RNA from mature leaves of these difficult-to-extract trees was optimized after screening nine different methods. The DNase I-, and proteinase K treatment-free modified method, consisting of extraction with CTAB method followed by TRIzol, yielded high-quality DNA-free RNA with an A260/A280 and A260/A230 ratios > 2.0. Extraction of RNA from Conocarpus, the most difficult one, was successful by avoiding the heat incubation of ground tissue in a buffer at 65 oC. Pre-warming of the buffer for 5–10 min was sufficient to extract good-quality RNA. RNA integrity number of the extracted RNA samples ranged between 7 and 9.1, and the gel electrophoresis displayed intact bands of 28S and 18S RNA. A cDNA library constructed from the RNA of P. cineraria was used for the downstream applications. Real-time qPCR analysis using the cDNA from P. cineraria RNA confirmed the quality. The extraction of good quality RNA from samples of the desert-growing P. cineraria (> 20-years-old) collected in alternate months of the year 2021 (January to December covering winter, spring, autumn, and the very dry and hot summer) proved the efficacy of the protocol. The protocol’s broad applicability was further validated by extracting good-quality RNA from 36 difficult-to-extract plant species, including tissues such as roots, flowers, floral organs, fruits, and seeds.ConclusionsThe modified DNase I and Proteinase K treatment-free protocol enables to extract DNA-free, high-quality, intact RNA from a total of 39 difficult-to-extract plant species belonging to 32 angiosperm families is useful to extract good-quality RNA from dicots and monocots irrespective of tissue types and growing seasons.

Tumor microenvironment modifications induced by afatinib in squamous cell carcinoma of the head and neck - a window-of-opportunity study (EORTC90111-24111).

The EORTC-90111-24111 phase II window study evaluated afatinib versus no preoperative treatment in patients with primary squamous cell carcinoma of the head and neck (HNSCC). We investigated afatinib-induced tumor and microenvironment modifications by comparing pre- and post-treatment tumor biopsies. Thirty treatment-naïve patients with primary HNSCC were randomized. Twenty-five patients received afatinib for 14 days before surgery (40mg 1x/day) and five patients were attributed to the control arm. Biopsies were taken at work-up and during surgery. Good quality RNA samples were used for omics analyses. The control arm was enlarged by samples coming from our previous similar window study (Schmitz et al. 2013). Immunohistochemistry analyses of afatinib-treated tumor biopsies showed a decrease in pEGFR (P≤.05) and pERK (P≤.05); an increase in CD3+ (P≤.01) and CD8+ (P≤.01) T-cell infiltration, and in CD3+ (P≤.05) T-cell density. RNA sequencing analyses of afatinib-treated tumor samples showed upregulation of inflammatory genes and increased expression scores of signatures predictive of response to PD-1 blockade (P≤.05). In post-treatment biopsies of afatinib-treated patients, two clusters were observed. Cluster 1 showed a higher expression of markers and gene sets implicated in epithelial-to-mesenchymal transition (EMT) and activation of cancer-associated fibroblasts (CAFs) compared to cluster 2 and controls. Short-term treatment with afatinib in primary HNSCC induces CD3+ and CD8+ tumor infiltration and, in some patients, EMT and CAFs activation. These results open perspectives to overcome resistance mechanisms to anti-HER therapy and to potentiate the activity of immune checkpoint inhibitors.

Development and validation of most efficient RNA isolation method from buffalo bull spermatozoa.

Being highly fragmented and low in concentration, isolation of good quality RNA from sperm cells is a big challenge. Attempts have been made to evaluate various sperm RNA isolation methods from purified buffalo bull sperm cells. Both, non-membrane and membrane-based methods have been evaluated for isolating RNA from Murrah buffalo sperms and compared for their respective efficacies. The traditional TRIzol, TRIzol-heat lysed (H-TRIzol) and cocktail of TCEP-RLT lysis buffer (Qiagen RNeasy mini kit)-TRIzol (C-TRIzol) based isopropanol isolation methods have been evaluated. H-TRIzol yielded best results among conventional methods. The combined T-RLT RNA isolation protocol yielded best quality and quantity compared to other membrane-based methods, due to high lytic property of cocktail of lysis reagents, necessary for complete breakdown of sperm membrane and RNA binding membrane for RNA isolation. Combined lysis performed by treatment with RLT-T and T-RLT differing in order of reagents used were also evaluated. T-RLT combination giving better results compared to RLT-T due to high gDNA contamination and membrane clogging in later protocol steps. Overall, in terms of total RNA quantity and quality per million spermatozoa, the heat-lysed TRIzol method (H-TRIzol) performs best among RNA separation techniques employed and is also quite easy to perform. This comparative evaluation of sperm RNA isolation protocols can be useful in deciding the best protocol for isolation of good quality and high concentration sperm RNA from buffalo semen, for transcriptome and other downstream studies.

Simplified protocol modification of TRIzol method for extraction of high-quality RNA yield from RNase-rich rat pancreas

The extraction of a sufficient quantity of intact RNA from RNase-rich rat pancreas for estimation of gene transcript levels has been a long-standing challenge. This study provided simple modifications in the steps involved in the standard TRIzol RNA extraction method to set up a reproducible, applicable, and efficient protocol to be routinely used in the laboratory. A Nanodrop spectrophotometer was used to evaluate the RNA concentration, and purity (A260/A280, and A260/A230 absorbent ratios). Gel electrophoresis was used to assess RNA integrity. Further analysis included sequential RT-qPCR of a housekeeping gene to evaluate the optimized protocol. The current study demonstrated that the modified protocol rendered significantly more RNA concentration (mean: 635.8 ± 210.5 ng/μL) compared to the standard protocol (mean: 77.2 ± 25.9 ng/μL). Moreover, the modified protocol produced an improvement in the RNA purity (mean :A260/A280 ratio = 1.89 ± 0.13; A260/A230 ratio = 1.7 ± 0.16) compared to the standard protocol (mean: A260/A280 ratio = 1.7 ± 0.26; A260/A230 ratio = 2.5 ± 1.9). Additionally, RT-qPCR analysis revealed that the RNA extracted using the modified protocol resulted in significantly decreased (P < 0.001) Ct values (decreased by 6 Ct units) compared to the standard protocol, reflecting the good quality of the RNA. Conclusion: This study succeeded in providing golden tips to extract a high yield of good-quality RNA from RNase-rich rat pancreas for the sequential gene expression assays.

Comparison of NTRK fusion detection methods in microsatellite-instability-high metastatic colorectal cancer

Tropomyosin receptor kinase (TRK) inhibitors have been approved for metastatic solid tumors harboring NTRK fusions, but the detection of NTRK fusions is challenging. International guidelines recommend pan-TRK immunohistochemistry (IHC) screening followed by next generation sequencing (NGS) in tumor types with low prevalence of NTRK fusions, including metastatic colorectal cancer (mCRC). RNA-based NGS is preferred, but is expensive, time-consuming, and extracting good-quality RNA from FFPE tissue is challenging. Alternatives in daily clinical practice are warranted. We assessed the diagnostic performance of RNA-NGS, FFPE-targeted locus capture (FFPE-TLC), fluorescence in situ hybridization (FISH), and the 5′/3′ imbalance quantitative RT-PCR (qRT-PCR) after IHC screening in 268 patients with microsatellite-instability-high mCRC, the subgroup in which NTRK fusions are most prevalent (1–5%). A consensus result was determined after review of all assay results. In 16 IHC positive tumors, 10 NTRK fusions were detected. In 33 IHC negative samples, no additional transcribed NTRK fusions were found, underscoring the high sensitivity of IHC. Sensitivity of RNA-NGS, FFPE-TLC, FISH, and qRT-PCR was 90%, 90%, 78%, and 100%, respectively. Specificity was 100% for all assays. Robustness, defined as the percentage of samples that provided an interpretable result in the first run, was 100% for FFPE-TLC, yet more limited for RNA-NGS (85%), FISH (70%), and qRT-PCR (70%). Overall, we do not recommend FISH for the detection of NTRK fusions in mCRC due to its low sensitivity and limited robustness. We conclude that RNA-NGS, FFPE-TLC, and qRT-PCR are appropriate assays for NTRK fusion detection, after enrichment with pan-TRK IHC, in routine clinical practice.

Comparison of Eleven RNA Extraction Methods for Poliovirus Direct Molecular Detection in Stool Samples.

Direct detection by PCR of poliovirus RNA in stool samples provides a rapid diagnostic and surveillance tool that can replace virus isolation by cell culture in global polio surveillance. The sensitivity of direct detection methods is likely to depend on the choice of RNA extraction method and sample volume. We report a comparative analysis of 11 nucleic acid extraction methods (7 manual and 4 semiautomated) for poliovirus molecular detection using stool samples (n = 59) that had been previously identified as poliovirus positive by cell culture. To assess the effect of RNA recovery methods, extracted RNA using each of the 11 methods was tested with a poliovirus-specific reverse transcription-quantitative PCR (RT-qPCR), a pan-poliovirus RT-PCR (near-whole-genome amplification), a pan-enterovirus RT-PCR (entire capsid region), and a nested VP1 PCR that is the basis of a direct detection method based on nanopore sequencing. We also assessed extracted RNA integrity and quantity. The overall effect of extraction method on poliovirus PCR amplification assays tested in this study was found to be statistically significant (P < 0.001), thus indicating that the choice of RNA extraction method is an important component that needs to be carefully considered for any diagnostic based on nucleic acid amplification. Performance of the methods was generally consistent across the different assays used. Of the 11 extraction methods tested, the MagMAX viral RNA isolation kit used manually or automatically was found to be the preferable method for poliovirus molecular direct detection considering performance, cost, and processing time. IMPORTANCE Poliovirus, the causative agent of poliomyelitis, is a target of global eradication led by the World Health Organization since 1988. Direct molecular detection and genomic sequencing without virus propagation in cell culture is arguably a critical tool in the final stages of polio eradication. Efficient recovery of good-quality viral RNA from stool samples is a prerequisite for direct detection by nucleic acid amplification. We tested 11 nucleic acid extraction methods to identify those facilitating sensitive, fast, simple, and cost-effective extraction, with flexibility for manual and automated protocols considered. Several different PCR assays were used to compare the recovered viral RNA to test suitability for poliovirus direct molecular detection. Our findings highlight the importance of choosing a suitable RNA extraction protocol and provide useful information to diagnostic laboratories and researchers facing the choice of RNA extraction method for direct molecular virus detection from stool.

Longitudinal Effects of 1-Year Smoking Cessation on Human Bronchial Epithelial Transcriptome

Longitudinal Effects of 1-Year Smoking Cessation on Human Bronchial Epithelial Transcriptome

Use of dissected paraffin block tissue as a source of mRNA for transcriptional profiling and biomarker identification: a review, with preliminary findings in adrenocortical carcinoma tissue.

Cancer tissue obtained by biopsy or at surgery is usually handled and stored as formalin-fixed, paraffin-embedded (FFPE) blocks. While primarily prepared for histological examination, this material represents a valuable resource that is stable and transportable, and which is ideal for examination in 3 dimensions. It has been used for DNA and protein analysis but the potential for transcriptional profiling has been little exploited: the quality of the extracted RNA is uncertain and there are few reports of its efficient use. We review the background and practicalities of this approach and describe a pilot study as a worked example in which RNA of good yield and quality could be consistently obtained from differentiated areas of adrenocortical carcinoma (ACC) tissue.

Single-cell transcriptomics provides insights into hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetic heart disease that is characterized by unexplained segmental hypertrophy that is usually most pronounced in the septum. While sarcomeric gene mutations are often the genetic basis for HCM, the mechanistic origin for the heterogeneous remodeling remains largely unknown. A better understanding of the gene networks driving the cardiomyocyte (CM) hypertrophy is required to improve therapeutic strategies. Patients suffering from HCM often receive a septal myectomy surgery to relieve outflow tract obstruction due to hypertrophy. Using single-cell RNA sequencing (scRNA-seq) on septal myectomy samples from patients with HCM, we identify functional links between genes, transcription factors, and cell size relevant for HCM. The data show the utility of using scRNA-seq on the human hypertrophic heart, highlight CM heterogeneity, and provide a wealth of insights into molecular events involved in HCM that can eventually contribute to the development of enhanced therapies.

Development of an optimal protocol for isolation and purification of human granulosa cells in patients with different ovarian reserves.

The aim of the current study was to develop an accurate and reproducible method for isolation of granulosa cells (GCs) in patients with different ovarian reserves. The cells of healthy individuals and patients with polycystic ovary syndrome (PCOS) were isolated using a modified two-step Percoll density gradient centrifugation. The cells of patients with poor ovarian response (POR) were isolated using a one-step method suitable for samples containing few cells. Cells extracted using these purification techniques were compared regarding cell yield, viability and purity using immunocytochemistry, flow cytometry, Cell Counting Kit-8, western blotting and RNA integrity analysis. The purity and activity of the cells in the POR group were comparable with those in the healthy and PCOS groups and no statistically significant differences were identified. Furthermore, isolated cells analyzed for RNA integrity indicated good quality RNA and presented an RNA integrity number of 8-10, demonstrating that the technique enabled the isolation of GCs from different types of patients. Thus, a reliable and reproducible technique for the isolation of pure GCs with high yield is described in the present study. This protocol provides an efficient method targeted to patients with different ovarian reserve functions that enables the preparation of GCs for evaluating their molecular functions.

A Comprehensive Analysis of Northern versus Liquid Hybridization Assays for mRNAs, Small RNAs, and miRNAs Using a Non-Radiolabeled Approach.

Northern blotting (NB), a gold standard for RNA detection, has lost its charm due to its hands-on nature, need for good quality RNA, and radioactivity. With the emergence of the field of microRNAs (miRNAs), the necessity for sensitive and quantitative NBs has again emerged. Here, we developed highly sensitive yet non-radiolabeled, fast, economical NB, and liquid hybridization (LH) assays without radioactivity or specialized reagents like locked nucleic acid (LNA)- or digoxigenin-labeled probes for mRNAs/small RNAs, especially miRNAs using biotinylated probes. An improvised means of hybridizing oligo probes along with efficient transfer, cross-linking, and signal enhancement techniques was employed. Important caveats of each assay were elaborated upon, especially issues related to probe biotinylation, use of exonuclease, and bioimagers not reported earlier. We demonstrate that, while the NBs were sensitive for mRNAs and small RNAs, our LH protocol could efficiently detect these and miRNAs using less than 10–100 times the total amount of RNA, a sensitivity comparable to radiolabeled probes. Compared to NBs, LH was a faster, more sensitive, and specific approach for mRNA/small RNA/miRNA detection. A comparison of present work with six seminal studies is presented along with detailed protocols for easy reproducibility. Overall, our study provides effective platforms to study large and small RNAs in a sensitive, efficient, and cost-effective manner.

Detection of SARS-CoV-2 infection by RT-PCR test: factors influencing interpretation of results.

In this current pandemic of coronavirus disease 2019 (COVID-19), prompt interventions in terms of early detection and clinical management along with isolation of positive cases is of utmost importance. This helps to limit not only the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections but also the morbidity and mortality associated with it. Different strategies for screening of COVID-19 in containment zones and non-containment areas include testing of symptomatic patients and their contacts in fever clinics, hospital-based testing, testing on demand and population-based screening. The choice of tests like reverse-transcription polymerase chain reaction (RT-PCR), rapid antigen testing (RAT) or antibody test depends upon these strategies and also the turnaround time. Currently, RT-PCR is considered the gold standard for COVID-19 detection. This commentary provides the insights and experiences on COVID-19 diagnosis by RT-PCR. The utility of this test is limited by several false positive, false negative and inconclusive results at early stages of infection, scarcity of reagents and lack of well-equipped labs including trained staff. Moreover, appropriate sample collection and transport, standard laboratory protocols, stringent quality control norms, good quality RNA extraction kits, PCR kits with suitable primers can help in improving accuracy of the test results. A careful assessment of clinical, radiological and molecular findings is required for identifying potential cases of COVID-19.

Glyoxal fixation facilitates transcriptome analysis after antigen staining and cell sorting by flow cytometry.

A simple method for extraction of high quality RNA from cells that have been fixed, stained and sorted by flow cytometry would allow routine transcriptome analysis of highly purified cell populations and single cells. However, formaldehyde fixation impairs RNA extraction and inhibits RNA amplification. Here we show that good quality RNA can be readily extracted from stained and sorted mammalian cells if formaldehyde is replaced by glyoxal-a well-characterised fixative that is widely compatible with immunofluorescent staining methods. Although both formaldehyde and glyoxal efficiently form protein-protein crosslinks, glyoxal does not crosslink RNA to proteins nor form stable RNA adducts, ensuring that RNA remains accessible and amenable to enzymatic manipulation after glyoxal fixation. We find that RNA integrity is maintained through glyoxal fixation, permeabilisation with methanol or saponin, indirect immunofluorescent staining and flow sorting. RNA can then be extracted by standard methods and processed into RNA-seq libraries using commercial kits; mRNA abundances measured by poly(A)+ RNA-seq correlate well between freshly harvested cells and fixed, stained and sorted cells. We validate the applicability of this approach to flow cytometry by staining MCF-7 cells for the intracellular G2/M-specific antigen cyclin B1 (CCNB1), and show strong enrichment for G2/M-phase cells based on transcriptomic data. Switching to glyoxal fixation with RNA-compatible staining methods requires only minor adjustments of most existing staining and sorting protocols, and should facilitate routine transcriptomic analysis of sorted cells.

Plasmodium falciparum Allelic Diversity: A Comparison of DNA Extraction from Isolates Collected on Rapid Diagnostic Tests (Rdts) and Filter Paper

Background:To perform molecular epidemiologic studies based on large cohorts, material such as RDTs or filter papers are useful for biological sample collection and extraction of RNA or DNA of good quality. Thus, we aimed to assess the quality of DNA extracted from malaria rapid diagnostic tests (RDTs) stored at various temperatures for the analysis of Plasmodium falciparum genetic diversity.Methods:Febrile patients benefitted from free malaria diagnosis using microscopy in a malaria sentinel site, at the Regional Hospital Estuaire-Melen, in Gabon, in 2015. P. falciparum isolates were collected onto one filter paper and 2 similar RDTs devices (Acon®) per patient. Nucleic acids were extracted with QiAmp Qiagen kit from paper and RDTs and the quality of the DNA was analyzed by msp1 gene amplification.Results:Msp1gene amplification was achieved in nucleic acids extracted from all filter papers and RDTs devices (n = 45, 100%). K1 alleles were detected in 93.3% (n = 42/45) of the samples and Mad20 alleles in 73.3% (n = 33/45). The number and the intensity of K1 and/or Mad20 fragments were comparable according to the sample collection material and the storage conditions (room temperature vs −20°C) of the samples. The size of the fragments indicating allelic diversity was comparable in 80% (n=36) of the samples.Conclusion:These data show that RDTs are a valuable source of DNA for malaria parasite genetic polymorphism analysis. Storage conditions of the devices did not influence the quality of DNA extracted from RDTs device, although some alleles may be missed.

Extraction of High-quality RNA from Metabolite and Pectin Rich Recalcitrant Calyx Tissue of Hibiscus sabdariffa L.

Hibiscus sabdariffa L. is no stranger to the field of pharmacology, as its calyx extract is highly rich in beneficial compounds and has been demonstrated to possess antihyperglycemic, antihypertension, anticancer and antioxidant properties. Thus, it is labeled it as a functional food with great health benefits and therapeutic potentials. The medicinal and nutritional components of the calyx are well reported. On the contrary, not much is known about the molecular machineries governing the biosynthesis of beneficial compounds in this plant. Obtaining good yields of high-quality RNA is crucial for the success of downstream research pertaining to molecular biology. However, the presence of high quantities of phenolic compounds, polysaccharides, mucilage and pectin in the fibrous calyx tissue poses major challenges for RNA extraction in H. sabdariffa. Here, we modified a CTAB-based method for efficient extraction of high-quality RNA from the calyx tissue. High quality RNA samples having RNA integrity number of more than eight were successfully extracted. The purities of RNA samples were also confirmed by the A260/280 and A260/230 values. Subsequent successful preparation of a sequencing library using one of the RNA samples extracted via the modified CTAB method further emphasized the efficiency of this extraction protocol and quality of the RNA samples. The results showed that the modified CTAB method was effective in extracting good quality RNA from the challenging calyx tissue of Hibiscus sabdariffa L. suitable for sensitive downstream application.

RNA Extraction from Endoscopic Ultrasound-Acquired Tissue of Pancreatic Cancer Is Feasible and Allows Investigation of Molecular Features.

Transcriptome analyses allow the distinguishing of pancreatic ductal adenocarcinoma (PDAC) subtypes, exhibiting different prognoses and chemotherapy responses. However, RNA extraction from pancreatic tissue is cumbersome and has been performed mainly from surgical samples, which are representative of < 20% of cases. The majority of PDAC patients undergo endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA), but RNA has been rarely extracted from EUS-TA with scanty results. Herein, we aimed to determine the best conditions for RNA extraction and analysis from PDAC EUS-TA samples in order to carry out molecular analyses. PDAC cases underwent diagnostic EUS-TA, with needles being a 25G fine needle aspiration (FNA) in all patients and then either a 20G lateral core-trap fine needle biopsy (FNB) or a 25G Franseen FNB; the conservation methods were either snap freezing, RNALater or Trizol. RNA concentration and quality (RNA integrity index; RIN) were analyzed and a panel of genes was investigated for tissue contamination and markers of molecular subtype and aggressivity through qRT-PCR. Seventy-four samples from 37 patients were collected. The median RNA concentration was significantly higher in Trizol samples (10.33 ng/uL) compared with snap frozen (0.64 ng/uL; p < 0.0001) and RNALater (0.19 ng/uL; p < 0.0001). The RIN was similar between Trizol (5.15) and snap frozen samples (5.85), while for both methods it was higher compared with RNALater (2.7). Among the needles, no substantial difference was seen in terms of RNA concentration and quality. qRT-PCR analyses revealed that samples from all needles were suitable for the detection of PDAC subtype markers (GATA6 and ZEB1) and splice variants associated with mutational status (GAP17) as well as for the detection of contaminating tissue around PDAC cells. This is the first study that specifically investigates the best methodology for RNA extraction from EUS-TA. A higher amount of good quality RNA is obtainable with conservation in Trizol with a clear superiority of neither FNA nor FNB needles. RNA samples from EUS-TA are suitable for transcriptome analysis including the investigation of molecular subtype and splice variants expression.

Optimized liquid-based cytology for the cellular and molecular analysis of oral keratinocytes: A promising diagnostic tool.

Liquid-based cytology (LBC) has improved exfoliative cytology by facilitating the extraction of more precise information from epithelial cells. The aim of this study was to optimize a protocol using a conventional cytobrush to perform LBC, obtaining oral keratinocytes for their further cellular and molecular analysis. LBC was performed in 30 healthy donors from buccal mucosa. We evaluated the use of diethyl pyrocarbonate (DEPC)-treated Dulbecco's Modified Eagle Medium (DMEM) medium right after the collection of the cells. Cell morphology and viability were determined by Orcein staining and flow cytometry, respectively. RNA was extracted by the trizol method, and evaluated with spectrometry and electrophoresis. Finally, RNA was copied into cDNA and GAPDH and TLR2 genes were amplified by reverse transcription polymerase chain reaction (RT-PCR) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) using specific primers. Only DEPC-treated DMEM preserved the viability of intact intraepithelial keratinocytes. RNA quantity and quality improves in samples treated with DEPC. RNA integrity is comparable with a cell line control. GAPDH gene was successfully amplified by RT-PCR and RT-qPCR. Therefore, LBC performed under these conditions becomes a reproducible technique for the retrieval of intraepithelial oral keratinocytes with good cell viability for cytomorphometric analysis, and extraction of good RNA quality suitable for molecular analyses such as PCR. We propose this LBC protocol as a complementary method to the cellular and molecular study of oral mucosa pathologies; however, it requires further study.