The authors thank Gr&#225;inne Tierney and Silvia Bellissimo for their editorial assistance.

The protocol follows the guidelines of the IRST Human Research Ethics Committee.
NOTE: In this protocol, we isolated DNA from urine samples to perform a UCF DNA integrity analysis. Lncap and MRC cell lines were used to construct standards. Techniques such as DNA extraction, DNA quantification (spectrophotometer and real-time PCR for the control gene, STOX1), and real-time PCR for specific oncogenes were performed (Figure 1).
1. Urine Collection and Pr...

<ol>
	<li>Francis, G., Stein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+Cell-Free+Tumour+DNA+in+the+Management+of+Cancer.">Circulating Cell-Free Tumour DNA in the Management of Cancer.</a> Int.J.Mol.Sci. 16 (6), 14122-14142 (2015).</li><li>Bryzgunova, O. E., Laktionov, P. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+Nucleic+Acids+in+Urine:+Sources,+Structure,+Diagnostic+Potential.">Extracellular Nucleic Acids in Urine: Sources, Structure, Diagnostic Potential.</a> Acta Naturae. 7 (3), 48-54 (2015).</li><li>Szarvas, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deletion+analysis+of+tumor+and+urinary+DNA+to+detect+bladder+cancer:+urine+supernatant+versus+urine+sediment.">Deletion analysis of tumor and urinary DNA to detect bladder cancer: urine supernatant versus urine sediment.</a> Oncol.Rep. 18 (2), 405-409 (2007).</li><li>Togneri, F. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+complexity+of+urothelial+bladder+cancer+revealed+in+urinary+cfDNA.">Genomic complexity of urothelial bladder cancer revealed in urinary cfDNA.</a> Eur.J.Hum.Genet. , (2016).</li><li>Zonta, E., Nizard, P., Taly, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+DNA+Integrity,+Applications+for+Cancer+Research.">Assessment of DNA Integrity, Applications for Cancer Research.</a> Adv.Clin.Chem. 70, 197-246 (2015).</li><li>Hao, T. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+cell-free+DNA+in+serum+as+a+biomarker+for+diagnosis+and+prognostic+prediction+of+colorectal+cancer.">Circulating cell-free DNA in serum as a biomarker for diagnosis and prognostic prediction of colorectal cancer.</a> Br.J.Cancer. 111 (8), 1482-1489 (2014).</li><li>Salvi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Urine+Cell-Free+DNA+Integrity+Analysis+for+Early+Detection+of+Prostate+Cancer+Patients.">Urine Cell-Free DNA Integrity Analysis for Early Detection of Prostate Cancer Patients.</a> Dis.Markers. 2015, 574120 (2015).</li><li>Casadio, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Urine+cell-free+DNA+integrity+as+a+marker+for+early+prostate+cancer+diagnosis:+a+pilot+study.">Urine cell-free DNA integrity as a marker for early prostate cancer diagnosis: a pilot study.</a> Biomed.Res.Int. 2013, 270457 (2013).</li><li>Casadio, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Urine+cell-free+DNA+integrity+as+a+marker+for+early+bladder+cancer+diagnosis:+preliminary+data.">Urine cell-free DNA integrity as a marker for early bladder cancer diagnosis: preliminary data.</a> Urol.Oncol. 31 (8), 1744-1750 (2013).</li><li>Salvi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+cell-free+AR+and+CYP17A1+copy+number+variations+may+associate+with+outcome+of+metastatic+castration-resistant+prostate+cancer+patients+treated+with+abiraterone.">Circulating cell-free AR and CYP17A1 copy number variations may associate with outcome of metastatic castration-resistant prostate cancer patients treated with abiraterone.</a> Br.J.Cancer. 112 (10), 1717-1724 (2015).</li><li>Ishkanian, A. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+array+CGH+identifies+novel+regions+of+genomic+alteration+in+intermediate-risk+prostate+cancer.">High-resolution array CGH identifies novel regions of genomic alteration in intermediate-risk prostate cancer.</a> Prostate. 69 (10), 1091-1100 (2009).</li><li>Oxley, J. D., Winkler, M. H., Gillatt, D. A., Peat, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Her-2/neu+oncogene+amplification+in+clinically+localised+prostate+cancer.">Her-2/neu oncogene amplification in clinically localised prostate cancer.</a> J.Clin.Patho. 55 (2), 118-120 (2002).</li><li>Nord, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Focal+amplifications+are+associated+with+high+grade+and+recurrences+in+stage+Ta+bladder+carcinoma.">Focal amplifications are associated with high grade and recurrences in stage Ta bladder carcinoma.</a> Int.J.Cancer. 126 (6), 1390-1402 (2010).</li><li>Tabach, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amplification+of+the+20q+chromosomal+arm+occurs+early+in+tumorigenic+transformation+and+may+initiate+cancer.">Amplification of the 20q chromosomal arm occurs early in tumorigenic transformation and may initiate cancer.</a> PLoS One. 6 (1), e14632 (2011).</li></ol>

UCF DNA integrity analysis is a new, non-invasive method for assessing DNA integrity in urine. It was recently proposed for the early diagnosis of bladder9 and prostate cancers7,8. A number of advantages and disadvantages of the UCF DNA integrity test are discussed here, together with future prospects.
The main advantage of the approach is that it offers an inexpensive, non-invasive method and a simple protocol to study urine as a potential source of biomarkers, requiring...

Cell-free DNA can be detected in blood and urine due to cell death by apoptotic or necrotic mechanisms. Cell-free DNA in blood has been widely studied for diagnostic and prognostic purposes in various diseases, especially cancer1. However, less is known about the role of urinary cell-free (UCF) DNA. UCF DNA may originate from blood passing through the glomerular filtration system or from cells that come directly into contact with this body fluid 2 (e.g., urothelial cells or prostatic cells). The use of UCF DNA as a source of biomarkers has mainly been investigated for the early diagnosis of renal, bladder, and prostate cancer due to the high percentage of UCF DNA coming directly from urinary tract cells3,4.
Little is known about UCF DNA and the best methods for isolating and characterizing it. Given the hypothesis that tumor cells release longer DNA fragments than normal cells, the evaluation of cell-free DNA integrity has been studied in an attempt to elucidate the origin of DNA in the blood circulation5. Some studies have demonstrated that cell-free DNA integrity in blood represents a good diagnostic test for many types of cancer6, and the same hypothesis has been proposed in relation to urine7-9.
This paper describes a new method for UCF DNA integrity analysis with a potential application to bladder and prostate cancer detection. In particular, the integrity of UCF DNA fragments longer than 250 bp was tested in 4 regions known to have an increased DNA copy number in solid tumors, including prostate and bladder cancer: c-MYC (8q24.21), HER2 (17q12.1), BCAS1 (20q13.2), and AR (Xq12)10-14. Specific oncogenes, rather than random sequences, were chosen to increase the probability of finding them in the cell-free fraction of cancer patients. One of the main advantages of this method is that it is flexible and that other regions can also be selected on the basis of tumor type and characteristics.

<table border="0" cellpadding="0" cellspacing="0" width="779">
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:277px;">QIAamp DNA Mini Kit 
			&#160;</td>
			<td style="width:216px;">Qiagen</td>
			<td style="width:119px;">51304</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:277px;">iQ SYBR&#160;Green Supermix, 100 x 50 &#181;l rxns, 2.5 ml (2 x 1.25 ml)</td>
			<td style="width:216px;">Biorad</td>
			<td style="width:119px;">1708880</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:277px;">IDT custom DNA oligos&#160;</td>
			<td style="width:216px;">IDT&#160;</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">HPLC purification, 100nMole DNA oligo</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;">NanoDrop 1000 Spectrophotometer</td>
			<td style="width:216px;">Thermo Scientific</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Other spectrophotometric methods could also be used to quantify DNA</td>
		</tr>
		<tr height="74">
			<td height="74" style="height:74px;width:277px;">Rotor-Gene 6000</td>
			<td style="width:216px;">Corbett</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Another Real Time PCR instrument could also be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">microcentrifuge</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">one centrifuge for 50 ml tubes</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">incubator</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">&#160;-80&#176;C freezer</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">-20&#176;C freezer</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">10 ul pipette</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">20 ul pipette</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">200 ul pipette</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">1000 ul pipette</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">pipette tips (10;20;200;1000)</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">1,5 ml tubes</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">50ml tubes</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">15 ml tubes</td>
			<td style="width:216px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">Rotor-Disc 72 Rotor</td>
			<td style="width:216px;">Corbett</td>
			<td>&#160;9018899</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Strip Tubes and Caps, 0.1 ml (250)</td>
			<td style="width:216px;">Qiagen</td>
			<td style="width:119px;">981103</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">Collection Tubes (2 ml)</td>
			<td style="width:216px;">Qiagen</td>
			<td style="width:119px;">19201</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">Buffer AL (264 ml)</td>
			<td style="width:216px;">Qiagen</td>
			<td style="width:119px;">19075</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:277px;">Proteinase K (10ml)</td>
			<td style="width:216px;">Qiagen</td>
			<td style="width:119px;">19133</td>
			<td></td>
		</tr>
	</tbody>
</table>

cell-free dna integrity analysis in urine samples

Although the presence of circulating cell-free DNA in plasma or serum has been widely shown to be a suitable source of biomarkers for many types of cancer, few studies have focused on the potential use of urine cell-free (UCF) DNA. Starting from the hypotheses that normal apoptotic cells produce highly fragmented DNA and that cancer cells release longer DNA, the potential role of UCF DNA integrity was evaluated as an early diagnostic marker capable of distinguishing between patients with prostate or bladder cancer and healthy individuals.
A UCF DNA integrity analysis is proposed on the basis of four quantitative real-time PCRs of four sequences longer than 250 bp: c-MYC, BCAS1, HER2, and AR. Sequences that frequently have an increased DNA copy number in bladder and prostate cancers were chosen for the analysis, but the method is flexible, and these genes could be substituted with other genes of interest. The potential utility of UCF DNA as a source of biomarkers has already been demonstrated for urologic malignancies, thus paving the way for further studies on UCF DNA characterization. The UCF DNA integrity test has the advantage of being non-invasive, rapid, and easy to perform, with only a few milliliters of urine needed to carry out the analysis.

The total free DNA concentration was quantifiable by spectrophotometry for all samples analyzed, showing a range of between 1.51 and 138 ng/&#181;L. Five control samples were used for reproducibility of the data: two independent real-time experiments were performed for c-MYC, HER2, BCAS1, AR, and STOX1. The coefficients of variation (CV) were then calculated for each gene (Table 2), with a good degree of reproducibility between...

Watch this Scientific Journal Video about Cell-Free DNA Integrity Analysis in Urine Samples at JoVE.com

Cell-Free DNA Integrity Analysis in Urine Samples

A method for analyzing DNA integrity in the cell-free supernatant fraction of urine samples is proposed. The method is suitable for early detection of urological malignancies and has proven accurate for the early diagnosis of bladder cancer.

Although the presence of circulating cell-free DNA in plasma or serum has been widely shown to be a suitable source of biomarkers for many types of ...

The overall goal of this method is to assess the integrity of urine cell-free DNA at specific oncogene sequences. This method can help answer key questions in the urological cancer field, such as early non-invasive diagnosis of bladder and prostate cancer. The main advantage of this technique is that it is easy to do and to analyze.The implications of this technique extend towards diagnosis of urological malignancies, because they normally release cells and free nucleic acids in urine. Though this method can provide insight into urinary samples, it can also be applied to other systems such as serum or plasma. Generally, individuals new to this method would struggle because the concentration of urine cell-free DNA is often low.We first had the idea for this method when we tried to find a simple method for non-invasive early detection of bladder cancer. To begin the procedure, obtain a 50 milliliter clean catch first morning urine sample that has been stored at four degrees Celsius for no more than three hours. Invert the sample twice and then partition the sample into two 50 milliliter conical centrifuge tubes.Centrifuge the sample at 850 times G for 10 minutes at four degrees Celsius. Then, for each tube transfer 10 milliliters of the upper part of the supernatant to two five milliliter tubes, leaving at least two milliliters of supernatant above the pellet. Discard the pellets and store the supernatant at minus 80 degrees Celsius.Repeat this process for additional urine samples as needed. To begin DNA purification, for each sample thaw an aliquot of urine supernatant. Vortex the thawed sample and invert the tube twice.Place one milliliter of the sample into a five milliliter tube, and store the remainder at minus 80 degrees Celsius. Prepare a DNA purification kit suitable for urine samples according to the manufacturer's instructions. Add 100 microliters of proteinase K and one milliliter of lysis buffer to the sample and mix well with a pipette.Incubate the sample at 56 degrees Celsius for 15 minutes. During incubation, prepare the wash buffers in a spin column. After incubation, allow the sample to cool to room temperature and then add one milliliter of absolute ethanol and mix well by pipetting.Transfer 650 microliters of the sample to the column. Centrifuge at 6000 times G for one minute. Replace the collection tube and repeat this process until all of the sample has been loaded onto the column.Then add 500 microliters of the first wash buffer and centrifuge the column at 6000 times G for one minute. Replace the collection tube, add 500 microliters of the second wash buffer, and centrifuge the column at max speed for three minutes. Place the column in a clean collection tube and centrifuge at max speed for another three minutes to remove residual wash buffer.Transfer the column to a clean 1.5 milliliter micro centrifuge tube. Load 50 microliters of elution buffer onto the column and allow the buffer to soak into the column for seven minutes. Then centrifuge the column at 6000 times G for one minute.Pipette the eluate back into the column and centrifuge the column at max speed for one minute to obtain the urine cell-free DNA. To begin preparing the standards, first isolate DNA from an appropriate cell line using a purification kit. Quantify the DNA from each purified urine sample in the cell line with a spectrophotometer per the kit manufacturer's instructions.Dilute the UCF DNA to one nanogram per microliter and store the diluted samples at minus 20 degrees Celsius until ready for the integrity test. Dilute the cell line DNA to create six, 100 microliter standards of different concentrations. Store the standards at minus 20 degrees Celsius.To begin the DNA integrity test, thaw the UCF DNA samples, the standards, the appropriate PCR primers, and green supermix on ice. Then set up the 72-well rotor disc plate with strip tubes. Place two, 10 microliter aliquots of standard and then each sample into wells.Prepare two wells of 10 microliter RNase-free water as negative controls. For each filled well, prepare a mix of one microliter of each primer, 12.5 microliters of green supermix, and 6.5 microliters of RNase-free water. Transfer 15 microliters of the mix into each filled well, and then transfer the wells into a 72-well rotor disc.Perform the PCR with a realtime instrument according to the manufacturer's specifications. Using the instrument software, check if any replicates have a cycling threshold value difference of one or more. Discard those samples from the analysis and evaluate the median cycling threshold for the remaining samples.Perform melting analysis on each sample with a median cycling threshold value of 36 or less to evaluate the PCR product specificity. Then use the standard curve to determine a concentration in nanograms per microliter for each applicon. Urine cell-free DNA was isolated and the DNA integrity was evaluated in four regions that show increased DNA copy number in solid tumors.A control sequence was also evaluated to verify that the DNA quantity in each sample was sufficient for the integrity test. The total free DNA concentration and the coefficients of variation were calculated for each gene. This method shows 73%sensitivity and 84%specificity for detecting bladder cancer, but only 58%sensitivity and 44%specificity for prostate cancer.Once mastered, this technique can be done in one working day if it is performed properly. Following this procedure, other methods like digital PCR or next generation sequencing can be performed in order to answer additional questions like copy number inducer of the genes of interest. After watching this video you should have a good understanding of how to isolate cell free DNA from urine in a very simple manner, and how to study the integrity of specific regions of interest using real time PCR approaches.

cell-free-dna-integrity-analysis-in-urine-samples

Research

JoVE Journal

Cancer Research

13.7K vues.  Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS. The overall goal of this method is to assess the integrity of urine cell-free DNA at specific oncogene sequences. This method can help answer key questions in the urological cancer field, such as early non-invasive diagnosis of bladder and prostate cancer. The main advantage of this technique is that it is easy to do and to analyze.The implications of this technique extend towards diagnosis of urological malignancies, because they normally release cells and free nucleic acids in urine....