High DNA Research Articles

Molecular mechanism of high glucose-induced mitochondrial DNA damage in retinal ganglion cells.

Mitochondrial DNA damage in retinal ganglion cells (RGCs) may be closely related to lesions of glaucoma. RGCs were cultured with different concentrations of glucose and grouped into 3 groups, namely normal control (NC) group, Low-Glu group, and High-Glu group. Cell viability was measured with cell counting kit-8, and cell apoptosis was measured using flow cytometry. The DNA damage was measured with comet assay, and the morphological changes of damaged mitochondria in RGCs were observed using TEM. Western blot analyzed the expression of MRE11, RAD50, and NBS1 protein. Cell viability of RGCs in Low-Glu and High-Glu groups were lower than that of NC group in 48 and 96 h. The cell apoptosis in NC group was 4.9%, the Low-Glu group was 12.2% and High-Glu group was 24.4%. The comet imaging showed that NC cells did not have tailings, but the low-Glu and high-Glu group cells had tailings, indicating that the DNA of RGCs had been damaged. TEM, mitochondrial membrane potential, ROS, mitochondrial oxygen consumption, and ATP content detection results showed that RGCs cultured with high glucose occurred mitochondrial morphology changes and dysfunction. MRE11, RAD50, and NBS1 protein expression associated with DNA damage repair pathway in High-Glu group declined compared with Low-Glu group. Mitochondrial DNA damage caused by high glucose will result in apoptosis of retinal ganglion cells in glaucoma.

Abstract 5014: Analytical validation of a complete system for detection and characterization of genomic aberrations in circulating tumor DNA

Abstract Cell-free DNA (cfDNA) fragments are readily detected at a low concentration in the human blood stream. In healthy patients cfDNA is primarily derived from apoptosis of hematopoietic cells. In cancer patients circulating DNA derived from tumor cells (ctDNA) undergoing apoptosis, shedding, and necrosis contribute to total cfDNA. Next generation sequencing (NGS) of cfDNA isolated from patient plasma can be used to fully characterize cancer driven changes in the tumor DNA including the relative contribution of cfDNA, single nucleotide variants (SNVs), small insertions and deletions (Indels), larger deletions, regions of amplified DNA, and structural rearrangements. Frontage has developed a complete lab system for analysis of circulating cfDNA including automated sample extraction, preparation and sequencing of libraries targeting exon sequences of 293 oncology-related genes, and a bioinformatic reporting system. The Frontage sample extraction process uses a post-extraction size selection step to remove high molecular weight DNA derived from lysed blood cells in the plasma sample to increase the sensitivity of detection of ctDNA. The NGS platform couples hybridization-based selection of genomic DNA fragments derived from protein-coding exons with deep sequencing to ~4,000X gross coverage on the NextSeq 2000. The bioinformatic pipeline integrates unique molecular barcode-based generation of consensus reads for each template molecule, somatic variant calling with GATK Mutect2 and FreeBayes, and removal of false positive variants by comparison to a 60 samples healthy patient data set. Analytical validation was performed for each component of the system. For verification of the sample extraction process, cfDNA was extracted in duplicate from four lots of pooled K2 EDTA plasma of healthy patients as well as individual K2 EDTA plasma of colorectal cancer (CRC) patients in four independent extraction runs. The mean yields of cfDNA from healthy samples ranged from 2.3 - 4.2 nanograms per ml plasma and all 32 of the isolated cfDNA aliquots from healthy patient plasma showed a prominent peak around 167 nt with minimal contamination from high molecular weight DNA. For validation of the NGS and bioinformatics platform a set of 8 different reference cfDNAs were processed through four independent runs of library preparation, sequencing, and analysis. For each of the validation runs, greater than 97% of 208 SNVs and Indels with expected allele frequencies (AF) between 2-3% were detected by the platform with higher levels of accuracy for variants at above 3% AF. Two or less false positive variants per run were detected out of 278,000 nucleotides of verified non-mutated sequence that overlapped with the 293 gene panel. Four known DNA amplification events were detected in each of the validation runs. Data from characterization of CRC and other clinical samples with the system will be presented. Citation Format: Ericca Stamper, Weiming Shen, Aman Pruthi, Casey Nagel, Marcin Piechota, Katarzyna Tomala, Qi Wei, David Willoughby. Analytical validation of a complete system for detection and characterization of genomic aberrations in circulating tumor DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5014.

Abstract 6937: High throughput single cell simultaneous DNA and RNA sequencing identified cell-of-origin of breast cancer

Abstract Understanding the relationship between genotype and phenotype in breast cancer cells has been challenging at single cell resolution, mainly because existing high-throughput methods are limited to measuring a single modality and data must be integrated indirectly via computational methods. To address this challenge, we developed wellDR-seq, a high-throughput single cell method that can simultaneously measure the single cell whole genome and transcriptome directly from thousands of single cells in parallel. Using this method, we profiled 17,427 single cells in 6 different ER+ breast cancer patients with either premalignant disease (Ductal-carcinoma-in-situ) or invasive ductal carcinoma (IDC). From these data we identified the epithelial cell-of-origin in 3 cases, showing that ER+ breast cancer cells originated from Luminal Hormone Responsive (LumHR) in the normal breast tissues. We also found that autosomal somatic copy number aberrations were exclusively present in LumSec (< 2%) and LumHR epithelial cells, while chrX gain or loss also occurred in stromal cells (eg fibroblast and endothelial) but a low frequency (<2%) in our datasets. Additionally, our data show the impact of subclonal copy number profiles on gene expression programs, which reflects both gene dosage effects in CNA regions and more complex deregulation in copy-neutral regions. wellDR-seq offers a powerful tool for large-scale single cell genome and transcriptome simultaneous sequencing across different clinical samples, opens new avenue to investigate genotype and phenotypes interactions, identify tumor cells origins, reveal somatic copy number and mutation events, quantify the gene dosage effect and discerning differential genes expression between tumor subclones. Citation Format: Kaile Wang, Rui Ye, Shanshan Bai, Zhenna Xiao, Lei Yano, Jianzhuo Li, Yiyun Lin, Emi Sei, Steven Lin, Alastair Thompson, Savitri Krishnamurthy, Nicholas Navin. High throughput single cell simultaneous DNA and RNA sequencing identified cell-of-origin of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6937.

Abstract 2292: Impact of delayed processing on cfDNA quantity and quality using STRECK cfDNA tubes: Connect Pilot Study

Abstract Interest in cell-free DNA detection for multi-cancer early detection and tumor monitoring is growing.1 Prospective evaluations of liquid biopsy assays are critical, and knowledge gaps in standard collection and preparation practices must be addressed for adequate assay execution.2 The NCI Connect for Cancer Prevention Cohort Study (Connect) aims to study new approaches in early detection. A pilot study was conducted with the STRECK Cell-Free DNA BCT tube to determine the impact of processing time on cfDNA quantity and quality utilizing two complementary quality control assays. 4 STRECK DNA BCT tubes were drawn from 40 donors. Plasma samples were analyzed, with half processed immediately and the other half stored for five days before processing. Two QC assays were performed to compare results at the two processing time points. The Alu EFIRM assay measured Alu element concentration (copies/mL). The Cell-free DNA ScreenTape assay evaluated Qubit DNA concentration (μg/mL) and %cfDNA. Descriptive statistics and paired sample t-tests were performed to compare mean concentrations at the two processing time points, with and without identified samples with cytolysis. Median, mean, and range were recorded for each assay measure (Table 1). A reduction in cfDNA quantity was observed at the 5-day processing time point. Five 5-day processing samples were identified with high DNA quantity and a high Alu element concentration. The five samples experienced hemolysis and clotting as a result of handling and processing at odds with standard protocol. There was a significant difference between the mean DNA quantities of the processing time points following exclusion of the five samples. There was no change in significance between the mean Alu concentration and %cfDNA following exclusion (Table 2). Both assays successfully detected samples with high nuclear DNA, a major contaminant for cfDNA assays, and identified a reduction in cfDNA at the 5-day processing time point. Proper handling and processing procedures are necessary to avoid cell lysis and maximize cfDNA quality and yield. This pilot establishes a starting point for future evaluations of liquid biopsy tube types, processing delays, and preanalytical cfDNA quality variables. Citation Format: Jazmyn Bess, Domonique Hopkins, Norma Diaz Mayoral, Heather Cooley, Angela de Palatis, David T. Wong, Stephanie Weinstein Oshinsky, Christian Abnet, Marie-Josephe Horner, Amanda Black, Michelle Brotzman, Kathleen Wyatt, Lynn Sorbara, Matthew Young, Mia Gaudet, Nicolas Wentzensen, Mickey Williams, Christopher Karlovich, Eric Greenbank, David Elashoff, Fang Wei, Feng Li. Impact of delayed processing on cfDNA quantity and quality using STRECK cfDNA tubes: Connect Pilot Study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2292.

Abstract 3670: Reducing the patient burden for ctDNA biomarkers: Advancing small volume home-based collection technologies

Abstract There is broad consensus from regulatory agencies, clinicians and patients for the need to move to decentralized trials while focusing on patient-centric approaches with the COVID-19 pandemic being the catalyst. This requires the development of new sample collection capabilities and workflows to ensure that the necessary biomarkers can be measured. Circulating tumor DNA (ctDNA) has become an increasingly important biomarker for cancer detection and genetics, and monitoring patients during treatment. Typical measurements of ctDNA involve venous draws of >10mls of whole blood that require patients to be in clinic. Here, we test the feasibility of using a new collection device, Tasso+, to collect capillary blood for ctDNA analysis using the Guardant360 panel. A pilot of whole blood microsamples (< 1 mL) with a cfDNA yield of 0.7-1.4 ng/ml spiked to 0.5% MAF with Seraseq ctDNA reference material. This resulted in detection of ~20% of the total expected variants across variant classes showing the feasibility of using the G360 panel to detect low volume/low MAF samples. Initial testing of Tasso+ collected samples revealed a 5-10x increase in high MW gDNA compared to traditional venipuncture. SPRI bead-based size selection was used in the extraction protocol to remove >95% of the high MW DNA, resulting in a 35% loss of target cfDNA fraction. Traditional venipuncture samples and Tasso+ samples were collected from 5 cancer patients and run using the G360 platform. Microsamples detected 75% of the variants across all variant classes found in venipuncture samples. Tasso+ lost sensitivity of variants when the MAF was <0.5%. To expand usage of Tasso+ to at-home collection of blood for ctDNA analysis, we sought to determine if lyophilization of the Streck DNA BCT RUO tube reagent could still provide stability to samples and a potential framework for at-home collections. Venipuncture and Tasso+ samples were collected from control patients, pooled and spiked with Seraseq cfDNA reference material. Samples were aliquoted into standard liquid Streck tubes or tubes with lyophilized reagent at the concentration per manufacturer’s directions and evaluated for stability over time. The Tasso+ samples with a target MAF between 0.5%-2.0% detected ~26% of all variants compared to the standard samples with a similar MAF. Lyophilization of the Streck reagent had minimal effect (<20% reduction in variants detected) on the reagent’s performance as there were approximately an equal number of total variants detected when comparing liquid and lyophilized samples for both the standard tubes and Tasso+ samples. Overall, these results provide support and a framework for using a home-based patient-centric sampling approach for monitoring ctDNA from cancer patients in clinical development. Citation Format: Brad R. Evans, Robert J. Foley, Steven M. Townson, Emily J. Welch, Kevin P. Bateman. Reducing the patient burden for ctDNA biomarkers: Advancing small volume home-based collection technologies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3670.

Abstract 326: Matched fresh frozen and FFPE patient tissues reveal the enhanced sensitivity and data quality of a novel DNA library prep method

Abstract In cancer genomics, a common source of DNA is formalin-fixed, paraffin-embedded (FFPE) tissue from patient surgical samples, where in most cases high quality fresh or frozen tissue samples are not available. FFPE DNA poses many notable challenges for preparing NGS libraries, including low input amounts and highly variable damage from fixation, storage, and extraction methods. It is difficult to obtain libraries with sufficient coverage and the sequencing artifacts arising from damaged DNA bases confound somatic variant detection. Additionally, many laboratories process FFPE tumor samples alongside matched, high quality, normal DNA and many library prep workflows are not readily compatible with both sample types. We developed a novel NGS library prep method compatible with both high quality and very low quality FFPE DNA samples, employing a novel enzymatic DNA repair mix, enzymatic fragmentation mix, and PCR master mix. To validate this workflow on real patient sample sets, we obtained DNA extracted from matched tumor and normal tissue of various tissue types preserved by both fresh frozen and FFPE methods. The FFPE DNA samples ranged in quality from DNA integrity number (DIN) 1.5 to 6.8, including samples stored for nearly 3 decades. We prepared libraries using this method compared against other library prep workflows and sequenced them by WGS and target capture. We assessed the performance of these workflows by library yield, library quality metrics, depth and evenness of coverage, and somatic variant calling with fresh frozen-extracted DNA providing the gold standard for library quality and mutation content. This new enzymatic fragmentation-based library prep workflow not only reduced the false positive rate in somatic variant detection by repairing damage-derived mutations in FFPE DNA samples but also improved the library yield, library quality metrics (including mapping, chimeras, and properly-paired reads), library complexity, coverage depth and uniformity, and hybrid capture library quality metrics. Comparing the variant calls from matched FFPE and frozen tissues revealed an improved sensitivity and accuracy of variant calling using this library prep method compared to mechanical shearing and other enzymatic fragmentation library prep approaches. This new suite of enzyme mixes allows even highly damaged FFPE samples to achieve high quality libraries with a greater sensitivity for somatic variant identification. The workflow is robust and flexible, compatible with both FFPE DNA and matched high quality DNA samples as well as automation-friendly for convenience in sample processing. Citation Format: Margaret R. Heider, Jian Sun, Brittany Sexton, Bradley W. Langhorst, Laura Blum, Pingfang Liu. Matched fresh frozen and FFPE patient tissues reveal the enhanced sensitivity and data quality of a novel DNA library prep method [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 326.

Abstract 7030: Reference materials for analysis of DNA methylation in cell-free circulating tumor DNA

Abstract Aberrant DNA methylation is associated with many cancers including breast, liver, bone, and colon and has been identified as a biomarker for early cancer screening. Liquid biopsies are beginning to screen for DNA methylation in cancer-derived DNA, but accurate assessment of methylation is not trivial, and methods like bisulfite sequencing can result in biased data. Reference materials for establishing the analytical validity of measurements of CpG methylation are not widely available. In order to prepare such reference materials, genomic DNA (gDNA) was extracted from the well characterized human reference cell line GM24385 and fragmented to a circulating tumor DNA (ctDNA)-like size distribution. This DNA was processed further to prepare CpG-methylated and unmethylated versions. The size distribution was determined by using the Bioanalyzer High Sensitivity DNA Kit (Agilent, Santa Clara, CA). Methylation status in the reference materials was confirmed by both digital PCR (dPCR) and NGS based methods. A digital PCR method was developed to analyze heterozygous single nucleotide polymorphisms (SNPs) using the Bio-Rad QX200™ Droplet Digital PCR (ddPCR) System. To determine methylation levels by NGS, the NEBNext™ Enzymatic Methyl-seq Kit was used (EM-seq). Paired-end sequencing of the libraries was performed on a NextSeq™ 2000 (Illumina, San Diego, CA). Data alignment to hg19 was done with the bwa-meth (Pedersen, BS., et al.) aligner, and assessment of methylation in the aligned data was done with MethylDackel (Ryan, D.). Each reference material had an average peak size of ~160 bp in length, similar to patient cfDNA. By dPCR, the unmethylated reference material had an average of 0.73% DNA methylation, while the methylated reference material had an average of 100.10% DNA methylation. Values can be above 100% by dPCR due to unequal representation of both alleles. By NGS, the unmethylated reference material had an average of 0.93 % CpG methylation, which was similar to the background of 1.13 % and 1.31 % for CHG and CHH methylation, respectively. The methylated reference material had an average of 93.95 % CpG methylation, with a background of 0.69 % and 0.74 % for CHG and CHH methylation, respectively. Because EM-seq relies on enzymatic protection and conversion steps, it may be that these reactions did not allow for full protection and full conversion, which led to values above 0 % for unmethylated and below 100 % for methylated materials. We have developed reference materials for the assessment of DNA methylation in ctDNA. One unmethylated and one methylated reference material was created. These reference materials can be mixed together to the level of methylation required to help aid in assay design, optimization, and validation. Citation Format: Alysha Higgs, Angelique Ryan, Jayanthi Ramprakash, Dana Ruminski Lowe, Yves Konigshofer, Catherine Huang, Andrew Anfora, Russell Garlick, Bharathi Anekella. Reference materials for analysis of DNA methylation in cell-free circulating tumor DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7030.

Abstract 3662: Cell-free DNA dynamics following neuroblastoma resection

Abstract Introduction: Prior studies have demonstrated the utility of circulating tumor DNA (ctDNA) as a biomarker in the postoperative period for oncologic risk stratification. However, its utility may be limited in the early postoperative period by surgical trauma causing an increase in total cell-free DNA (cfDNA) due to tissue destruction, inflammation, and wound healing. No studies have identified the optimal timing of postoperative sample collection in pediatric patients undergoing resection of high-risk neuroblastoma. The purpose of this study is to assess the postoperative dynamics of cfDNA following neuroblastoma resection to determine optimal timing for ctDNA investigations. Methods: An institutional database of banked cell-free DNA samples was retrospectively queried for patients with a diagnosis of neuroblastoma who had blood samples collected prior to resection and postoperative samples collected within 2 months of the operation. Plasma was collected from whole blood samples. cfDNA was extracted from plasma samples using the QIAGEN QIAsymphony SP system, and samples were quantified using the Advanced Analytical Fragment Analyzer Automated CE System with the High Sensitivity Genomic DNA Analysis Kit. Results: Seventeen patients were identified undergoing 18 total operations and 37 total blood draws yielding cfDNA. There were 12 male and 5 female patients. Median age at operation was 5.5 years (range 1.4y to 20.5y). Two patients were INRG stage L2, and 15 patients were stage M. Operative indications were primary tumor resection in 10 patients and resection of recurrence/progression in 8 patients. Three postoperative samples were drawn within 10 days of the operation, and 16 samples were collected between postoperative weeks 4 and 6. There was a statistically significant difference (p=0.029) in cfDNA yield between each timepoint sampled: preoperative (median 6ng/mL, range 2-30ng/mL), 0-10 days postop (median 34ng/mL, range 15 - 85 ng/mL), and 4-6 weeks postop (median 6ng/mL, range 2 - 17ng/mL). Pairing the pre- and post-operative samples for each patient, those drawn within 10 days had a median increased yield of 180% (range +67% to +652%) while the samples collected at 4-6 weeks had a median decreased yield of 23% (range -55% to +491%; p = 0.047). Of note, there were three outliers in the 4-6 week group who had increases in cfDNA yield of >200%. On further review of these charts, each patient was being treated for obstructive uropathy at the time the postoperative sample was collected. Conclusion: Plasma cfDNA yield increases in the early postoperative period before dropping by postoperative week 6. Tumor resection may be associated with an overall decrease in total cfDNA. Postoperative renal pathology may cause a persistent elevation in cfDNA. Further studies are necessary to clarify the role of ctDNA in the management of patients with neuroblastoma. Citation Format: Joshua N. Honeyman, Andrew Chi, Shakeel Modak, Fiorella Iglesias Cardenas, Michael P. La Quaglia, Neerav N. Shukla, J. Ted Gerstle. Cell-free DNA dynamics following neuroblastoma resection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3662.

Abstract 982: Variation of cell-free DNA concentrations in liquid biopsies

Abstract Introduction: Liquid biopsies are promising noninvasive tools for cancer detection. Variation in cell-free DNA concentrations (cfDNA-conc) has been observed between individuals with and without cancer. We assessed cfDNA-conc in 2287 treatment-naive individuals including those without cancer, with benign or high-risk conditions, or with one of eight cancer types. Methods: Plasma (0.3 to 9.8 mL) was separated from whole blood collected in Streck or EDTA tubes from individuals with bile duct, breast, colorectal, gastric, ovarian, liver, lung, pancreatic, or metastatic cancer (n=23, 54, 28, 26, 264, 75, 180, 31, 22, respectively) as well as benign or high-risk conditions (n=550, 133, respectively) such as cirrhosis or hepatitis B or C virus infection (HBV/HCV), and without cancer (n=901). cfDNA was extracted using the Qiagen QIAamp Circulating Nucleic Acid Kit. Quality and quantity were assessed using the High Sensitivity DNA assay on the Agilent Bioanalyzer. Total amount (ng) of cfDNA from all nucleosomal peaks was evaluated per volume (mL) of plasma to assess significance across cohorts using unpaired two-sample Wilcoxon tests. Results: We observed that in individuals without cancer, cfDNA-conc increased with age (Pearson R2=0.59; 18-40yrs vs 41-55yrs, vs 56-65yrs, vs 66-85yrs; p=2.31E-09, 1.50E-12, 8.31E-17, respectively). No difference was observed between cfDNA-conc from EDTA and Streck plasma from the same individual (n=9, p=0.359, Wilcoxon signed-rank test two-tailed). Individuals with benign adnexal masses or cirrhosis had similar cfDNA-conc compared to those without cancer while individuals with benign lung lesions or HBV/HCV had significantly different cfDNA-conc (p=0.70, 0.35, 6.96E-04, 1.88E-09, respectively). These observations were not affected by age. Individuals with cancer had significantly higher cfDNA-conc compared to those without cancer (bile duct p=2.08E-14, breast p=4.44E-16, colorectal p=6.04E-10, gastric p=5.93E-04, ovarian p=9.99E-16, liver p=1.22E-15, lung p=0, pancreatic p=8.57E-03, metastatic p=1.18E-06). Ovarian cancer exhibited higher cfDNA-conc than benign adnexal masses which was more pronounced in later stage disease (I/II p=3.83E-06, III/IV p=8.18E-08). Compared to cirrhosis or HBV/HCV we observed a stepwise increase in cfDNA-conc in liver cancer with progressing stage (0/A p= 6.50E-04, B p= 5.69E-10, C p= 1.47E-08). Higher cfDNA-conc were also observed with higher stage of lung cancer compared to benign lung lesions (I/II p=4.99E-03, III/IV p=3.89E-06). Using cfDNA-conc (ng/mL) as a single feature, we distinguished individuals with and without cancer with an AUC of 0.72 (95% CI=0.70-0.75). Conclusions: In a cohort of 2287 individuals, we observed cfDNA-conc increases with age and cancer stage that varied across cancer types. As a classifier, cfDNA-conc can be predictive of cancer status, yet further work is needed to understand the contribution of other comorbidities. Citation Format: Sarah Short, Akshaya V. Annapragada, Jamie E. Medina, Zachariah H. Foda, Dimitrios Mathios, Carolyn Hruban, Elaine J. Chiao, Kavya Boyapati, Adrianna Bartolomucci, Keerti Boyapati, Vilmos Adleff, Robert B. Scharpf, Victor E. Velculescu, Jillian Phallen. Variation of cell-free DNA concentrations in liquid biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 982.

Abstract 6651: Compromised TGFβ signaling and DNA repair primes immune poor tumors response to immune checkpoint blockade by activating NK cells

Abstract We investigated the interplay between transforming growth factor beta (TGFβ) regulation of immunosuppressive signaling and immunogenic DNA repair. Loss of TGFβ signaling by cancer cells is accompanied by increased use of error-prone repair. We described a transcriptomic score, βAlt, that reports the TGFβ/DNA repair functional relationship. Pan-cancer analysis showed that high βAlt cancers (i.e., low TGFβ and high error-prone DNA repair) are sensitive to chemoradiation and have a greater fraction of genome altered compared to low βAlt cancers. Defective mismatch repair is associated with T cell infiltration and response to immune checkpoint blockade (ICB), hence we investigated the immune context of bAlt. Unsupervised clustering of RNAseq profiles 12 independent immunocompetent mouse tumor derived transplant (mTDT) tumors based on βAlt score indicated that high βAlt was associated with immune poor phenotype and lack of type I interferon signatures. A similar relationship was evident in the bladder, breast, and lung TCGA data. A high βAlt, immune poor mTDT in which T cells were only 20% of 10% CD45 were treated with monotherapy consisting of single fraction 10 Gy radiation, anti-PD-L1 or TGFβ inhibition, dual or triple treatment. Only monotherapy or combinations with radiation significantly increased survival. However, these ICB resistant tumors responded to triple treatment. Response was accompanied by increased tumor infiltrating CD45+ cells (P=0.02), circulating CD8 T cells (P<0.001) and natural killer (NK) cells (P<0.001). As NK cells tripled and TGFβ broadly impairs NK cell effector function, we depleted NK cells to test whether they were required for the response to triple treatment. NK depletion completely abrogated response (P<0.00001) indicating NK cells can provoke an ICB response in high βAlt immune poor tumors. Both mouse tumors and human cancers show that loss of TGFβ signaling resulting in error-prone DNA damage response is strongly associated with immune poor tumors and suggests that TGFβ inhibition can override NK cell dysfunction to create vulnerability to ICB. Citation Format: Jade T. Moore, Jim Gkantalis, Ines Guix, Mary Helen Barcellos-Hoff. Compromised TGFβ signaling and DNA repair primes immune poor tumors response to immune checkpoint blockade by activating NK cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6651.

Abstract 132: DNA-PK inhibition to enhance etoposide therapy in neuroblastoma

Abstract Introduction. Neuroblastoma is the most common extracranial solid tumor in children and accounts for ~15% of all pediatric cancer deaths. DNA-PK, a key regulator of repair responses to double-strand DNA breakages induced by radiation or induction chemotherapy is used in the treatment of high-risk neuroblastomas. Here, we have demonstrated that high DNA-PK expression is associated with poor overall survival in a patient population, DNA-PK is highly activated in neuroblastoma cell lines, and inhibition of DNA-PK enhances therapeutic effects of DNA damaging therapies. Methods. DNA double-strand break damage was induced with etoposide, a topoisomerase II inhibitor. DNA-PK activity was inhibited with peposertib or DNA-PK siRNA. DNA-PK Ser2056 phosphorylation was analyzed in MYCN amplified (SK-NDZ, BE(2)-C, LAN-1) and MYCN non-amplified (SK-N-AS, SK-N-SH) cell lines. Clonogenic and proliferation assays were used to evaluate the efficacy of peposertib in combination with etoposide in BE-2-C and SK-N-DZ neuroblastoma cell lines. DSB-induced DNA repair was visualized with confocal laser scanning microscopy using γ-H2AX immunofluorescence. Western blot was used to confirm inhibition of DNA-PKcs (pDNA-PKcs S2056) and analyze cleaved PARP expression in combination groups. Results. DNA-PK inhibition resulted in enhancement of etoposide cytotoxic therapy (BE-2-C IC50 ET = 2.77 ± 0.2, ET+Pep 0.76 ± 0.04; SK-N-DZ IC50 ET = 0.55 ± 0.06, IC50 ET+Pep = 0.11 ± 0.02) in both BE-2-C and SK-N-DZ cell lines. Immunofluorescence analysis detected γH2AX foci increase in the etoposide and peposertib combination group. DNA-PK inhibition in combination with etoposide treatment significantly increased PARP cleavage in BE-2-C and SK-N-DZ cell lines. The effect of DNA-PK knockdown on neuroblastoma cell survival was even more pronounced compared to DNA-PK inhibition with peposertib. DNA-PK knockdown by siRNA alone increased PARP cleavage to the levels comparable to 2 µM etoposide treatment. The combination of etoposide and DNA-PK knockdown enhanced PARP cleavage even further in neuroblastoma cells. Conclusions. High DNA repair activity is commonly associated with cancer drug resistance. We have shown that DNA-PK activation is continuously supported in both MYCN amplified and MYCN non-amplified neuroblastoma cell lines. The importance of DNA-PK activity in neuroblastoma cell lines is confirmed with DNA-PK knockdown that leads to apoptosis in MYCN amplifiedneuroblastoma cell lines. In addition, the combination of DNA-PK inhibition or DNA-PK knockdown with DNA-damaging therapies stalled DNA damage response and enhanced neuroblastoma cell apoptosis. These findings demonstrate the significance of high DNA-PK activity in neuroblastoma cells and provide a potent therapeutic strategy to enhance neuroblastoma cell apoptosis with selective DNA-PK inhibition. Citation Format: Mahnaz Norouzi, Beibei Zhu, Tadahide Izumi, Eric J. Rellinger, B. Mark Evers, Piotr G. Rychahou. DNA-PK inhibition to enhance etoposide therapy in neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 132.

Abstract 4944: Divergent proteogenomic gene expression is driven by microenvironment across tumor types

Abstract Solid tumors develop through a complex series of genome and downstream expression alterations that interact with the local tissue microenvironment, leading to a transformed cell and malignant phenotype. With massive multi-omic data, recent proteogenomics studies have jointly analyzed RNA and protein expression to uncover new gene regulatory relationships; however, many of these studies focused on single tumor types and lack a generalizable view of joint RNA and protein expression. Here, we present the first pan-cancer analysis of sample-wise RNA to protein correlation (SRPC). We re-analyzed over 1,000 tumors across 10 tumor types from published proteogenomic data from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and the Applied Proteogenomics OrganizationaL Learning and Outcomes (APOLLO) Research Network. We identified a wide range of SRPC across all tumors (ρ range: -0.08 to 0.70, median: 0.45). We then analyzed tumor pathologic and molecular characteristics versus the range of SRPC. High SRPC tumors had high tumor purity by pathology review, by somatic DNA whole exome sequencing, and by RNA and protein purity scores. In contrast, low SRPC tumors had high immune cell and stromal cell expression scores as inferred by either protein or RNA based signatures. We observed marked differences in cell type populations estimated by expression in different SRPC tumor tranches (low SRPC: macrophages, endothelial cells, cancer-associated fibroblasts; high SRPC: CD4+ Th2 cells). Tumors expressed signaling pathways depending on their SRPC (low SRPC: hypoxia, inflammatory response, and KRAS signaling; high SRPC: DNA repair and E2F targets). SRPC also stratifies tumors with distinct somatic DNA alterations (low SRPC: HRAS and NF2; high SRPC: TP53, MEN1, high Tumor Mutational Burden and high DNA chromosomal instability). Finally, we found that cancer driver genes displayed divergent gene-wise RNA to protein correlations (GRPC) among tumor types with a median absolute deviation interquartile range of 0.1 - 0.2, suggesting tumor-type-specific regulation. In summary, divergent RNA and protein expression is driven, in part, by tumor microenvironment composition across tumor types. Tumors with a diverse cellular microenvironment display a summation of RNA and protein expression resulting from this cell type diversity leading to a low SRPC, while tumors predominated by tumor cells display coordinated RNA and protein expression levels resulting from a pure clonal or cell type leading to a high SRPC. This first deep analysis into sample-wise RNA to protein correlation represents a large proteogenomic community resource for informing biomarker analysis by modality and by tranches of tumor microenvironment. The views expressed in this abstract are solely of the authors and do not reflect the official policy of the Departments of Army/Navy/Air Force, Department of Defense, USUHS, HJF, or U.S. Government. Citation Format: Joseph LaMorte, Nicholas Bateman, Thomas Conrads, Robert F. Browning, Craig D. Shriver, Robert L. Kortum, Matthew D. Wilkerson. Divergent proteogenomic gene expression is driven by microenvironment across tumor types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4944.

Rapid Silicification of a DNA Origami with Shape Fidelity.

High-fidelity patterning of DNA origami nanostructures on various interfaces holds great potential for nanoelectronics and nanophotonics. However, distortion of a DNA origami often occurs due to the strong interface interactions, e.g., on two-dimensional (2D) materials. In this study, we discovered that the adsorption of silica precursors in rapid silicification can prevent the distortion caused by graphene and generates a high shape-fidelity DNA origami-silica composite on a graphene interface. We found that an incubation time of 1 min and silicification time of 16 h resulted in the formation of DNA origami-silica composites with the highest shape fidelity of 99%. By comparing the distortion of the DNA origami on the graphene interface with and without silicification, we observed that rapid silicification effectively preserved the integrity of the DNA origami. Statistical analysis of scanning electron microscopy data indicates that compared to bare DNA origami, the DNA origami-silica composite has an increased shape fidelity by more than two folds. Furthermore, molecular dynamics simulations revealed that rapid silicification effectively suppresses the distortion of the DNA origami through the interhelical insertion of silica precursors. Our strategy provides a simple yet effective solution to maintain the shape-fidelity DNA origami on interfaces that have strong interaction with DNA molecules, expanding the applicable interfaces for patterning 2D DNA origamis.

Testing of the Effect of Food Additives on the DNA Isolation from Mackerel and Fish Products

Authentication of fish products by DNA analysis requires the extraction of high quality DNA without the presence of inhibitors. Many nucleic acid isolation methods are currently available; silicate centrifugal columns have become very popular due to their speed and ease of extraction. However, their disadvantage may be the principle based on DNA charge, which may be affected by food composition, or clogging due to a poor sample pretreatment. The aim of this work was to compare three DNA isolation methods using different principles (silicate centrifugal columns, modified magnetic beads, Cetrimonium bromide and chloroform extraction) and to evaluate their suitability for DNA isolation from fish muscle. The criteria assessed were the recovery, purity and amplifiability of the isolated DNA. Mackerel tissue was analysed without and with the addition of additives commonly used in the manufacture of fish products, namely diphosphates (E 450) and colorants (E 110 and E 124), and the selected method was subsequently applied to commercial fish products. The modified method using the detergent CTAB proved to be the most suitable.

Detection of Escherichia coli O157:H7 in Ground Beef Using Long-Read Sequencing.

Foodborne pathogens are a significant cause of illness, and infection with Shiga toxin-producing Escherichia coli (STEC) may lead to life-threatening complications. The current methods to identify STEC in meat involve culture-based, molecular, and proteomic assays and take at least four days to complete. This time could be reduced by using long-read whole-genome sequencing to identify foodborne pathogens. Therefore, the goal of this project was to evaluate the use of long-read sequencing to detect STEC in ground beef. The objectives of the project included establishing optimal sequencing parameters, determining the limit of detection of all STEC virulence genes of interest in pure cultures and spiked ground beef, and evaluating selective sequencing to enhance STEC detection in ground beef. Sequencing libraries were run on the Oxford Nanopore Technologies' MinION sequencer. Optimal sequencing output was obtained using the default parameters in MinKNOW, except for setting the minimum read length to 1 kb. All genes of interest (eae, stx1, stx2, fliC, wzx, wzy, and rrsC) were detected in DNA extracted from STEC pure cultures within 1 h of sequencing, and 30× coverage was obtained within 2 h. All virulence genes were confidently detected in STEC DNA quantities as low as 12.5 ng. In STEC-inoculated ground beef, software-controlled selective sequencing improved virulence gene detection; however, several virulence genes were not detected due to high bovine DNA concentrations in the samples. The growth enrichment of inoculated meat samples in mTSB resulted in a 100-fold increase in virulence gene detection as compared to the unenriched samples. The results of this project suggest that further development of long-read sequencing protocols may result in a faster, less labor-intensive method to detect STEC in ground beef.

Impact of live feed substitution with formulated diets on the development, digestive capacity, biochemical composition, and rearing water quality of European lobster (Homarus gammarus, L.) larvae

The lobster aquaculture industry, constrained by limited access to viable and cost-effective feed sources, prompted an investigation into the potential of replacing live feeds with formulated diets for Homarus gammarus larval culture, exploring alternative protein ingredients. Four diets were tested on newly-hatched H. gammarus: live Artemia nauplii (ART), an extruded control diet with krill meal and fishmeal as main protein sources (CTRL), and diets with 15% of dietary protein replaced by shrimp waste meal (SWM) or black soldier fly meal (BSF).Results revealed significant diet-induced effects on digestive enzymes in H. gammarus larvae. ART-fed lobsters exhibited increased trypsin and amylase activities but lower lipase activity than those fed extruded diets, suggesting more efficient utilization of protein and carbohydrate in ART-fed larvae, while formulated diets compensated with efficient lipid utilization. BSF and SWM diets increased exo- and endochitinase activities, likely due to chitin presence. Additionally, CTRL and BSF-fed larvae exhibited elevated body glycogen content. ART-fed larvae displayed a significantly higher ratio of low DNA to high DNA bacteria in their rearing water, indicative of lower nutrient loading. Despite these diet-induced impacts, there was no dietary effect on growth and survival during H. gammarus larval development.The study suggests successful formulated feed utilization by homarid larvae, even with alternative ingredients like BSF and SWM, offering a promising solution to reduce reliance on live feeds in lobster aquaculture. Further research is crucial to assess the long-term implications of the observed physiological responses to the different diets in later life stages.

(264) Outcome of Intra-Cytoplasmic Sperm Injection ICSI with Testicular Sperm Aspiration (TESA) In Patients with High Sperm DNA fragmentation, Hospital Experience

Abstract Introduction Sperm DNA fragmentation (SDF) is considered as an important biomarker in the assessment of male fertility potential with contradictory results regarding its effect on ICSI. In our study we focus on the outcomes of Intra-Cytoplasmic Sperm Injection (ICSI) in male patients with high SDF using testicular spermatozoa (TESA). Objective To evaluate intra- cytoplasmic sperm injection (ICSI) outcomes in male patients with high SDF using testicular spermatozoa and analysis of the cofactors (Age, Smoking, Chemical Exposure and usage of Anti-oxidants agents) Methods Retrospective study, institutional experience. Results In our study, we evaluated 41 men with high-SDF levels who had a previous ICSI cycle from their ejaculates. A subsequent ICSI cycle was performed using spermatozoa retrieved through testicular sperm aspiration. The mean (SD) SDF level is 33.7%. live birth rate was 29.2% (12 out of 41) In addition of that, we analyzed the cofactors of men such as Age, Smoking, Chemical Exposure and usage of Anti-oxidants agents. The mean age is 33 %. Men received anti oxidants agent prior to TESA were 9 out of 12 (75%) Conclusions Intra-cytoplasmic sperm injection (ICSI) outcomes in male patients with high SDF using testicular spermatozoa has higher clinical pregnancy and higher chance of live-birth. The rate is higher with those who received anti-oxidant supplements for at least 6 moths. Disclosure No.

Lycopene prevents cell death in NRK-52E cells by inhibition of high glucose-activated DNA damage and apoptotic, autophagic, and necrotic pathways.

This study aims to investigate the effects of lycopene on apoptotic, autophagic, and necrotic pathways, oxidative status, and DNA damage in diabetic nephropathy at the molecular level. The sample of the study includes seven groups: lycopene (L), high glucose (G), high glucose + lycopene (GL), and control (C) groups tested at 12 and 24 h. The expression levels of genes in oxidative, apoptotic, autophagic, and necrotic cell death pathways are determined by reverse transcription-quantitative polymerase chain reaction analysis. The comet assay method is used for the analysis of DNA damage. It is observed that adding lycopene to high glucose for protective purposes reduces the expression of genes related to apoptosis, autophagy, and necrosis, as well as the DNA damage index, compared to cells given high glucose alone. Lycopene can be a safe and effective alternative agent.

Low-Toxicity and High-Efficiency Streptomyces Genome Editing Tool Based on the Miniature Type V-F CRISPR/Cas Nuclease AsCas12f1.

Genome editing tools based on SpCas9 and FnCpf1 have facilitated strain improvements for natural product production and novel drug discovery in Streptomyces. However, due to high toxicity, their editing requires high DNA transformation efficiency, which is unavailable in most streptomycetes. The transformation efficiency of an all-in-one editing tool based on miniature Cas nuclease AsCas12f1 was significantly higher than those of SpCas9 and FnCpf1 in tested streptomycetes, which is due to its small size and weak DNA cleavage activity. Using this tool, in Streptomyces coelicolor, we achieved 100% efficiency for single gene or gene cluster deletion and 46.7 and 40% efficiency for simultaneous deletion of two genes and two gene clusters, respectively. AsCas12f1 was successfully extended to Streptomyces hygroscopicus SIPI-054 for efficient genome editing, in which SpCas9/FnCpf1 does not work well. Collectively, this work offers a low-toxicity, high-efficiency genome editing tool for streptomycetes, particularly those with low DNA transformation efficiency.

Evaluation of Automated Magnetic Bead-Based DNA Extraction for Detection of Short Tandem Repeat Expansions With Nanopore Sequencing.

Long-read technologies such as nanopore sequencing provide new opportunities to detect short tandem repeat expansions. Therefore, a DNA extraction method is necessary that minimizes DNA fragmentation and hence allows the identification of large repeat expansions. In this study, an automated magnetic bead-based DNA extraction method and the required EDTA blood storage conditions as well as DNA and sequencing quality were evaluated for their suitability for repeat expansion detection with nanopore sequencing. DNA was extracted from EDTA blood, and subsequently, its concentration, purity, and integrity were assessed. DNA was then subjected to nanopore sequencing, and quality metrics of the obtained sequencing data were evaluated. DNA extracted from fresh EDTA blood as well as from cooled or frozen EDTA blood revealed high DNA integrity whereas storage at room temperature over 7 days had detrimental effects. After nanopore sequencing, the read length N50 values of approximately 9 kb were obtained, and based on adaptive sampling of samples with a known repeat expansion, repeat expansions up to 10 kb could be detected. The automated magnetic bead-based DNA extraction was sufficient to detect short tandem repeat expansions, omitting the need for high-molecular-weight DNA extraction methods. Therefore, DNA should be extracted either from fresh blood or from blood stored in cooled or frozen conditions. Consequently, this study may help other laboratories to evaluate their DNA extraction method regarding the suitability for detecting repeat expansions with nanopore sequencing.