We developed and benchmarked Exome Cancer Test v.2.0 (EXaCT-2), a novel whole-exome sequencing (WES) assay based on Agilent’s SureSelect hybrid-capture technology and expanded with custom probes targeting cancer-informative genomic regions. EXaCT-2 provides ~1,400 cancer genes with the depth of coverage typical of targeted panels, while achieving the genomic breadth to detect somatic copy number alterations (SCNAs), common cancer-related rearrangements, oncogenic viruses and B-cell receptor (BCR) clonotypes. Evaluated with a cancer patient cohort of 244 matched tumor/normal pairs and compared with clinically-validated results, EXaCT-2 achieved a mean sequencing depth of ~400× for critical cancer genes and ~100× for the remainder of the exome, with SCNA characterization showing improved boundary detection and overall segmentation. The assay demonstrated enhanced sensitivity for detecting sub-clonal, low-allele-frequency mutations missed by standard exome assays, such as mutations in GC-rich genes like KRAS. Analysis is performed by a modular, bespoke pipeline that leverages a workflow manager (Nextflow), in combination with containerized open-source tools. In addition to mutations and SCNAs, the pipeline reports common cancer rearrangements, hematologic oncogenic viruses, BCR clonotypes, and global molecular metrics, such as tumor mutational burden (TMB) and microsatellite instability (MSI). Collectively, these results establish EXaCT-2 as a comprehensive platform for integrated cancer genome profiling.

Background:The Inspiration4 (I4) mission, the first all-civilian orbital flight mission, investigated the physiological effects of short-duration spaceflight through a multi-omic approach. Despite advances, there remains much to learn about human adaptation to spaceflight's unique challenges, including microgravity, immune system perturbations, and radiation exposure. Methods:To provide a detailed genetics analysis of the mission, we collected dried blood spots pre-, during, and post-flight for DNA extraction. Telomere length was measured by quantitative PCR, while whole genome and cfDNA sequencing provided insight into genomic stability and immune adaptations. A robust bioinformatic pipeline was used for data analysis, including variant calling to assess mutational burden. Result:Telomere elongation occurred during spaceflight and shortened after return to Earth. Cell-free DNA analysis revealed increased immune cell signatures post-flight. No significant clonal hematopoiesis of indeterminate potential (CHIP) or whole-genome instability was observed. The long-term gene expression changes across immune cells suggested cellular adaptations to the space environment persisting months post-flight. Conclusion:Our findings provide valuable insights into the physiological consequences of short-duration spaceflight, with telomere dynamics and immune cell gene expression adapting to spaceflight and persisting after return to Earth. CHIP sequencing data will serve as a reference point for studying the early development of CHIP in astronauts, an understudied phenomenon as previous studies have focused on career astronauts. This study will serve as a reference point for future commercial and non-commercial spaceflight, low Earth orbit (LEO) missions, and deep-space exploration.

Cancer cohorts are now known to be associated with increased rates of clonal hematopoiesis (CH). We sort to characterize the hematopoietic compartment of patients with melanoma and non-small cell lung cancer (NSCLC) given our recent population level analysis reporting evolving rates of secondary leukemias. The advent of immune checkpoint blockade (ICB) has dramatically changed our understanding of cancer biology and has altered the standards of care for patients. However, the impact of ICB on hematopoietic myeloid clonal expansion remains to be determined. We studied if exposure to ICB therapy affects hematopoietic clonal architecture and if their evolution contributed to altered hematopoiesis. Blood samples from patients with melanoma and NSCLC (n = 142) demonstrated a high prevalence of CH. Serial samples (or post ICB exposure samples; n = 25) were evaluated in melanoma and NSCLC patients. Error-corrected sequencing of a targeted panel of genes recurrently mutated in CH was performed on peripheral blood genomic DNA. In serial sample analysis, we observed that mutations in DNMT3A and TET2 increased in size with longer ICB exposures in the melanoma cohort. We also noted that patients with larger size DNMT3A mutations with further post ICB clone size expansion had longer durations of ICB exposure. All serial samples in this cohort showed a statistically significant change in VAF from baseline. In the serial sample analysis of NSCLC patients, we observed similar epigenetic expansion, although not statistically significant. Our study generates a hypothesis for two important questions: (a) Can DNMT3A or TET2 CH serve as predictors of a response to ICB therapy and serve as a novel biomarker of response to ICB therapy? (b) As ICB-exposed patients continue to live longer, the myeloid clonal expansion may portend an increased risk for subsequent myeloid malignancy development. Until now, the selective pressure of ICB/T-cell activating therapies on hematopoietic stem cells were less known and we report preliminary evidence of clonal expansion in epigenetic modifier genes (also referred to as inflammatory CH genes).

Extended high throughput mutation profiling.

PDF - 3879K, AR-42 gene expression signature displays similarity to PTL and HDAC inhibitors.

The role of intratumor heterogeneity is becoming increasingly apparent in part due to expansion in single cell technologies. Clinically, tumor heterogeneity poses several obstacles to effective cancer therapy dealing with biomarker variability and treatment responses. Matrix stiffening is known to occur during tumor progression and contribute to pathogenesis in several cancer hallmarks, including tumor angiogenesis and metastasis. However, the effects of matrix stiffening on intratumor heterogeneity have not been thoroughly studied. In this study, we applied single-cell RNA sequencing to investigate the differences in the transcriptional landscapes between stiff and compliant MMTV-PyMT mouse mammary tumors. We found similar compositions of cancer and stromal subpopulations in compliant and stiff tumors but differential intercellular communication and a significantly higher concentration of tumor-promoting, M2-like macrophages in the stiffer tumor microenvironments. Interestingly, we found that cancer cells seeded on stiffer substrates recruited more macrophages. Furthermore, elevated matrix stiffness increased Colony Stimulating Factor 1 (CSF-1) expression in breast cancer cells and reduction of CSF-1 expression on stiffer substrates reduced macrophage recruitment. Thus, our results demonstrate that tissue phenotypes were conserved between stiff and compliant tumors but matrix stiffening altered cell-cell interactions which may be responsible for shifting the phenotypic balance of macrophages residing in the tumor microenvironment towards a pro-tumor progression M2 phenotype.

PDF - 3889K, AR-42 demonstrates higher activity against a panel of leukemia cell lines in contrast to PTL

PDF - 306K, Differentially expressed genes upon AR-42 treatment.

PDF - 107K, AR-42, unlike PTL, does not upregulate HMOX-1 as a consequence of ROS induction.

The supplementary methods contain a more detailed description of the analytic and experimental approach beyond the scope of the main methods section. Supplementary Figure S1. Ability of specific genomic lesions to predict epigenetic clustering. Supplementary Figure S2. ERRBS coverage. Supplementary Figure S3. Differential methylation at promoters and active enhancers. Supplementary Figure S4. DMC distribution. Supplementary Figure S5. Transcription factor binding site analysis at differentially methylated active enhancers in IDH2, DNMT3A, and IDH1/DNMT3A AMLs.

Clonal hematopoiesis (CH) represents clonal expansion of mutated hematopoietic stem cells detectable in the peripheral blood or bone marrow through next generation sequencing. The current prevailing model posits that CH mutations detected in the peripheral blood mirror bone marrow mutations with clones widely disseminated across hematopoietic compartments. We sought to test the hypothesis that all clones are disseminated throughout hematopoietic tissues by comparing CH in hip vs peripheral blood specimens collected at the time of hip replacement surgery. Here, we show that patients with osteoarthritis have a high prevalence of CH, which involve genes encoding epigenetic modifiers and DNA damage repair pathway proteins. Importantly, we illustrate that CH, including clones with variant allele frequencies >10%, can be confined to specific bone marrow spaces and may be eliminated through surgical excision. Future work will define whether clones with somatic mutations in particular genes or clonal fractions of certain sizes are either more likely to be localized or are slower to disseminate into the peripheral blood and other bony sites.

Abstract The I4 mission, the first all-civilian orbital flight mission, investigated the physiological effects of short duration spaceflight through a multi-omic approach. We analyzed telomere length, clonal hematopoiesis of indeterminate potential (CHIP), whole genome stability, cell-free DNA (cfDNA) cell lysis, and immune cell gene expression. Our results revealed telomere length dynamics similar to those observed in the NASA Twins Study and in astronauts spending 6 months on the ISS, with lengthening in space and shortening upon return to Earth. Our cell-type of origin analysis of cfDNA fragments revealed an increased presence of innate and adaptive immune cell signatures that persisted over a month after return to earth. No significant relationship between spaceflight and CHIP-related or whole genome abnormalities were observed. Longitudinal mitochondrial, ribosomal and immune function gene expression changes occurred across both adaptive and innate immune cells, suggesting adaptations to the space environment can extend months after return from spaceflight and alter immune function. Our findings provide valuable insights into the physiological consequences of short duration spaceflight and will serve as a reference point for future space tourism, low Earth-orbit (LEO) missions, and deep-space exploration.

Detailed information including ERRBS cluster identity, HELP cluster identity, cytogenetics, molecular profile, and limited profile of mutations and genetic perturbations.

PDF - 1495K, Quantification for the immunoblots shown in figure 5.

PDF - 77K, DAVID pathway analysis for downregulated genes (KEGG pathways).

Abstract The I4 mission, the first all-civilian orbital flight mission, investigated the physiological effects of short duration spaceflight through a multi-omic approach. We analyzed telomere length, clonal hematopoiesis of indeterminate potential (CHIP), whole genome stability, cell-free DNA (cfDNA) cell lysis, and immune cell gene expression. Our results revealed telomere length dynamics similar to those observed in the NASA Twins Study and in astronauts spending 6 months on the ISS, with lengthening in space and shortening upon return to Earth. Our cell-type of origin analysis of cfDNA fragments revealed an increased presence of innate and adaptive immune cell signatures that persisted over a month after return to earth. No significant relationship between spaceflight and CHIP-related or whole genome abnormalities were observed. Longitudinal mitochondrial, ribosomal and immune function gene expression changes occurred across both adaptive and innate immune cells, suggesting adaptations to the space environment can extend months after return from spaceflight and alter immune function. Our findings provide valuable insights into the physiological consequences of short duration spaceflight and will serve as a reference point for future space tourism, low Earth-orbit (LEO) missions, and deep-space exploration.

DMC identity and annotation for mouse Idh2, Dnmt3a, and Idh2/Dnmt3a cohorts.

PDF - 1783K, AR-42, unlike PTL, does not deplete thiols.