Name: RNA Fluorescence In Situ Hybridization to Localize the lncRNAs in Human Osteosarcoma Cells
Uploaded: 2023-06-16T14:30:00
Description: Watch this Scientific Journal Video about RNA Fluorescence In Situ Hybridization to Localize the lncRNAs in Human Osteosarcoma Cells at JoVE.com

rna fluorescence in situ hybridization to localize the lncrnas in human osteosarcoma cells

FISH for Long Non-Coding RNA Localization in Human Osteosarcoma Cells

Our understanding of the human genome has been greatly expanded by recent advances in whole-genome technology. About 93% of the human genome can be transcribed into RNAs, but only 2% of the RNAs can be translated into proteins; the remaining 98% of RNAs that have no protein translation function are called non-coding RNA (ncRNA)1. As a class of noncoding RNAs (ncRNAs), long ncRNAs (lncRNAs), containing over 200 nucleotides2, have attracted increasing attention due to their involvement in many physiological and pathological processes of the cells, such as differentiation, cycle control, apoptosis, migration, and invasion3,4,5. LncRNAs play their roles through various mechanisms, such as regulating chromatin structure and nuclear gene expression, controlling the mRNA splicing process, and posttranscriptional modification6. LncRNAs regulate the occurrence, development, and metastasis of malignancies at both the transcriptional and posttranscriptional levels. Transcriptional regulation is realized in the nucleus by affecting RNA transcription via binding to the chromosomal structures, while posttranscriptional regulation is realized in the cytoplasm by controlling the target genes via an endogenous competitive RNA (ceRNA) mechanism5, 7, 8. CeRNA has revealed a new mechanism of RNA interaction, namely that lncRNAs can act as a sponge to adsorb miRNAs and inhibit the miRNA-mediated degradation of related target genes9. Therefore, the information regarding the subcellular localization of lncRNAs, whether a specific lncRNA is located in the cytoplasm or nucleus, is important to help identify their biological functions.
At present, lncRNA localization is mainly detected by two methods, one is by nucleus/cytoplasm fraction isolation assay, and the other is by RNA FISH. In the former, RNAs in the cytoplasmic and the nuclear fractions are extracted respectively, and then PCR amplification is performed with specific lncRNA primers to detect the ratio of lncRNAs in the cytoplasm and nucleus. The advantage of this method is time efficiency, while the disadvantage is that the actual lncRNA localization is not directly reflected by the relative proportion of lncRNAs in the cytoplasm and nucleus. RNA FISH can detect lncRNA localization in cells through the design of lncRNA-specific antisense chain sequences followed by labeling with fluorescent dyes10. The RNA FISH methods have been improved with advances in probe techniques and detection methods, including fluorophore-labeled multiple oligo probe sets11, LNA probes12, and branched-DNA (bDNA) probes13. RNA FISH can not only detect the localization of lncRNA, but also detect the colocalization of other RNAs, DNA, or proteins by using double-color or multicolor immunofluorescence14.
In this work, we have included the detailed intracellular localization detection protocol of lncRNA small nucleolar RNA host gene 6 (SNHG6) in osteosarcoma cells (143B) by RNA FISH as an example. SNHG6 is a 600-730 nucleotide lncRNA in its mature spliced form and identified as a novel oncogene in diverse human cancers, including colorectal cancer, gastric cancer, ovarian clear cell carcinoma, osteosarcoma, and hepatocellular carcinoma15,16,17,18. Studies have confirmed the involvement of SNHG6 in biological behaviors of cancer cells, such as proliferation, EMT, and autophagy, and shown the cytoplasmic localization of SNHG6 where it may affect the target genes by binding (sponging) the miRNAs15,16,17. This detailed detection protocol of SNHG6 intracellular localization by RNA FISH is presented herein.

Author Spotlight: RNA FISH for Locating lncRNA-SNHG6 in Osteosarcoma Cells 

RNA Fluorescence In Situ Hybridization for Long Non-Coding RNA Localization in Human Osteosarcoma Cells

The scope of our research is to provide a detailed RNA FISH protocol that's providing a reference for scientists who want to perform RNA FISH experiments. Our research has established that RNA FISH can be used to localize lncRNA in human osteosarcoma cells. Our protocol provided a comprehensive experimental procedure and the precautions for RNA FISH using lncRNA-SNHG6 in human osteosarcoma cells as a reference.

Watch this Scientific Journal Video about RNA Fluorescence In Situ Hybridization to Localize the lncRNAs in Human Osteosarcoma Cells at JoVE.com

RNA Fluorescence In Situ Hybridization to Localize the lncRNAs in Human Osteosarcoma Cells  

To begin, after acquiring the long non-coding RNA of interest, incubate the hybridization buffer at 37 degrees Celsius for two hours. Next, dissolve the four optical density probe in 160 microliters of diethyl pyrocarbonate treated deionized water away from the light. Prepare 200 microliters of the probe mixture for each well, and set up a series of 50, 25, 12.5, and six micrograms per milliliter.Denature the probe mix at 73 degrees Celsius for five minutes. Take a 12-well cell culture plate containing 143B cells on sterile glass cover slips. Remove the medium and wash twice for five minutes with PBS.Place the cells on a shaker. Then remove the PBS and add 200 microliters of 100%ethanol to each well, fixing for 15 minutes at room temperature. Then remove the ethanol, add 200 microliters of 0.1%Triton X-100 to each well, and incubate for 15 minutes at room temperature.Remove 0.1%Triton X-100 and wash two times for five minutes with PBS. Next, remove PBS, add 200 microliters of two times sodium-saline citrate or SSC buffer into each well, and incubate for 30 minutes at 37 degrees Celsius. Remove two times SSC buffer, add 200 microliters of 70%ethanol into each well, and incubate for three minutes at room temperature.Discard the 70%ethanol, then add 200 microliters of 85%ethanol into each well and incubate for three minutes at room temperature. Next, discard the 85%ethanol, add 200 microliters of 100%ethanol to each well, and incubate for three minutes at room temperature. Afterward, absorb and discard the 100%ethanol and allow the wells to dry.Next, add 200 microliters of denatured probe mixture to each well, then incubate at 37 degrees Celsius overnight. The following day, remove samples from 37 degrees Celsius, discard the probe mixture, and add 200 microliters of preheated 0.4 times SSC 0.3%Tween 20 buffer to each well and wash for two minutes at room temperature. Remove the 0.4 times SSC 0.3%Tween 20 buffer.Add 200 microliters of two times SSC 0.1%Tween 20 buffer to each well and wash for two minutes at room temperature. Next, discard the two times SSC 0.1%Tween 20 buffer. Add 200 microliters of DAPI staining solution and stain for 20 minutes in the dark on a shaker.After staining, discard the DAPI solution and wash it with PBS for two minutes at room temperature. Lastly, add 50 microliters of mounting medium containing gum to the slide and place the glass cover slip to fix the slide. Representative SNHG6 FISH images in human osteosarcoma cells are shown.SNHG6 probe labeled with Cy3, which emits red fluorescence, showed that SNHG6 is mainly localized in the cytoplasm. A background color was observed when using a high concentration of probe.

Research

JoVE Journal

Cancer Research

The important roles of long non-coding RNAs (lncRNAs) in cancer have been studied, such as regulating the proliferation, epithelial-mesenchymal transition ...