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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Basic Knowledge in Soft Tissue Sarcoma

Sarcoma is rare and heterogenous with various subtypes having a different prognostic. Desmoid is a tumour with a local aggressiveness; GIST with KIT mutation responds massively to target treatment as IMATINIB, whereas soft tissue sarcoma and leiomyosarcoma are very aggressive with poor response to systemic therapies. Interventional radiology plays an important role in the diagnosis of sarcomas with image-guided percutaneous core needle biopsy being the most commonly used biopsy technique in the diagnosis of sarcomas. Biopsy access routes discussed with the surgeon, and skin access is tattooed. Surgery is a mainstay of sarcoma treatment; the resection can be large. Indeed, resection objective is R0 because quality of surgical margins impacts local control and survival. Radiotherapy is possible in neoadjuvant or in adjuvant treatment to improve local control rate. Recently radiotherapy enhancer injected percutaneously in soft tissue sarcoma has proven benefit in increasing the rate of R0 complete surgical resection. Several studies showed better local control rate linked with post-operative radiotherapy. In patients affected by oligometastatic disease, complete surgical resection of all metastatic sites is in fact considered the primary treatment because complete remission is critical for cure. The decision making to use local therapies is complex, depends upon diverse presentations and histologies, and should always be taken in a multidisciplinary discussion. Today, percutaneous image-guided treatments with ablation technologies (radiofrequency ablation, cryotherapy, microwaves ablation) provide high rate of durable local control for small-sized malignant deposit in many organs including lung, liver and bones. Sarcoma must be managed by multimodality treatment in expert reference centres. Such management has a considerable impact on the prognosis.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Watch and Wait Approach for Re-excision After Unplanned Yet Macroscopically Complete Excision of Extremity and Superficial Truncal Soft Tissue Sarcoma is Safe and Does Not Affect Metastatic Risk or Amputation Rate

Background: The benefits of systematic re-excision (RE) after initial unplanned excision (UE) of soft tissue sarcoma (STS) are unknown. Objective: The aim of this study was to evaluate the impact of delayed RE versus systematic RE after UE on overall survival (OS), metastatic relapse-free survival (MRFS), local relapse-free survival (LRFS), and rate of amputation. Methods: Patients who underwent complete UE, without metastasis or residual disease, for primary extremity or superficial STS between 2007 and 2013 were analyzed. The amputation rate, LRFS, MRFS, and OS were assessed in cases of systematic RE in sarcoma referral centers (Group A), systematic RE outside of community centers (Group B), or without RE (Group C). Results: Groups A, B, and C included 300 (48.2%), 71 (11.4%), and 251 (40.4%) patients, respectively. Median follow-up was 61 months and 5-year OS was 88.4%, 87.3%, and 88% in Groups A, B, and C, respectively (p = 0.22), while 5-year MFRS was 85.4%, 86.2%, and 84.9%, respectively (p = 0.938); RE (p = 0.55) did not influence MRFS. The 5-year LRFS was 83%, 73.5%, and 63.8% in Groups A, B and C, respectively (p = 0.00001). Of the 123 local recurrences observed, 0/28, 1/15, and 5/80 patients in Groups A, B, and C, respectively, required amputation (p = 0.41). Factors influencing LRFS were adjuvant radiotherapy [hazard ratio (HR) 0.21; p = 0.0001], initial R0 resection (HR 0.24, p = 0.0001), and Group A (HR 0.44; p = 0.01). Conclusion: Systematic RE in sarcoma centers offers best local control but does not impact OS. Delayed RE at the time of local relapse, if any, could be an option.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Modeling inter‐reader variability in clinical target volume delineation for soft tissue sarcomas using diffusion model

Abstract Background Accurate delineation of the clinical target volume (CTV) is essential in the radiotherapy treatment of soft tissue sarcomas. However, this process is subject to inter‐reader variability due to the need for clinical assessment of risk and extent of potential microscopic spread. This can lead to inconsistencies in treatment planning, potentially impacting treatment outcomes. Most existing automatic CTV delineation methods do not account for this variability and can only generate a single CTV for each case. Purpose This study aims to develop a deep learning‐based technique to generate multiple CTV contours for each case, simulating the inter‐reader variability in the clinical practice. Methods We employed a publicly available dataset consisting of fluorodeoxyglucose positron emission tomography (FDG‐PET), x‐ray computed tomography (CT), and pre‐contrast T1‐weighted magnetic resonance imaging (MRI) scans from 51 patients with soft tissue sarcoma, along with an independent validation set containing five additional patients. An experienced reader drew a contour of the gross tumor volume (GTV) for each patient based on multi‐modality images. Subsequently, two additional readers, together with the first one, were responsible for contouring three CTVs in total based on the GTV. We developed a diffusion model‐based deep learning method that is capable of generating arbitrary number of different and plausible CTVs to mimic the inter‐reader variability in CTV delineation. The proposed model incorporates a separate encoder to extract features from the GTV masks, leveraging the critical role of GTV information in accurate CTV delineation. Results The proposed diffusion model demonstrated superior performance with the highest Dice Index (0.902 compared to values below 0.881 for state‐of‐the‐art models) and the best generalized energy distance (GED) (0.209 compared to values exceeding 0.221 for state‐of‐the‐art models). It also achieved the second‐highest recall and precision metrics among the compared ambiguous image segmentation models. Results from both datasets exhibited consistent trends, reinforcing the reliability of our findings. Additionally, ablation studies exploring different model structures and input configurations highlighted the significance of incorporating prior GTV information for accurate CTV delineation. Conclusions The proposed diffusion model successfully generates multiple plausible CTV contours for soft tissue sarcomas, effectively capturing inter‐reader variability in CTV delineation.

Dong, Yafei [Yale Biomedical Imaging Institute Yal↗
DOE OSTI2021

Mithramycin A Radiosensitizes EWS:Fli1+ Ewing Sarcoma Cells by Inhibiting Double Strand Break Repair

The oncogenic EWS:Fli1 fusion protein is a key transcriptional mediator of Ewing sarcoma initiation, progression, and therapeutic resistance. Mithramycin A (MithA) is a potent and specific inhibitor of transcription mediated by the EWS:Fli1. We tested the hypothesis that pretreatment with MithA could selectively radiosensitize EWS:Fli1{sup +} tumor cells by altering the transcriptional response to radiation injury.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Local Control For High-Grade Nonrhabdomyosarcoma Soft Tissue Sarcoma Assigned to Radiation Therapy on ARST0332: A Report From the Childrens Oncology Group

The ARST0332 trial for pediatric and young adults with nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) used risk-based treatment including primary resection with lower-than-standard radiation doses to optimize local control (LC) while minimizing long-term toxicity in those requiring radiation therapy (RT). RT for high-grade NRSTS was based on extent of resection (R0: negative margins, R1: microscopic margins, R2/U: gross disease/unresectable); those with >5 cm tumors received chemotherapy (CT; ifosfamide/doxorubicin). This analysis evaluates LC for patients assigned to RT and prognostic factors associated with local recurrence (LR).

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Combined Preoperative Hypofractionated Radiotherapy With Doxorubicin-Ifosfamide Chemotherapy in Marginally Resectable Soft Tissue Sarcomas: Results of a Phase 2 Clinical Trial

There is no standard treatment for marginally resectable soft tissue sarcomas (STSs) of the extremities and trunk wall, and current approaches produce unsatisfactory results. We hypothesized that the combination of doxorubicin-ifosfamide (AI) chemotherapy and 5 × 5 Gy hypofractionated radiotherapy can generate a higher ratio of limb-sparing or conservative surgeries with negative microscopic margins (R0) and acceptable treatment toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Structural switching dynamically controls the doubly pseudoknotted Rous sarcoma virus–programmed ribosomal frameshifting element

A hallmark of retrovirus replication is the translation of two different polyproteins from one RNA through programmed –1 frameshifting. This is a mechanism in which the actively translating ribosome is induced to slip in the 5′ direction at a defined codon and then continues translating in the new reading frame. Programmed frameshifting controls the stoichiometry of viral proteins and is therefore under stringent evolutionary selection. Forty years ago, the first frameshifting stimulatory element was discovered in the Rous sarcoma virus. The ~120 nt RNA segment was predicted to contain a pseudoknot, but its 3D structure has remained elusive. Now, we have determined cryoEM and X-ray crystallographic structures of this classic retroviral element, finding that it adopts a butterfly-like double-pseudoknot fold. One “wing” contains a dynamic pyrimidine-rich helix, observed crystallographically in two conformations and in a third conformation via cryoEM. The other wing encompasses the predicted pseudoknot, which interacts with a second unexpected pseudoknot through a toggle residue, A2546. This key purine switches conformations between structural states and tunes the stability of interacting residues in the two wings. We find that its mutation can modulate frameshifting by as much as 50-fold, likely by altering the relative abundance of different structural states in the conformational ensemble of the RNA. Taken together, our structure–function analyses reveal how a dynamic double pseudoknot junction stimulates frameshifting by taking advantage of conformational heterogeneity, supporting a multistate model in which high Shannon entropy enhances frameshifting efficiency.

Science & Technology - Other Topics↗
DOE OSTI2024

Kaposi's sarcoma herpesvirus exploits the DNA damage response to circularize its genome

Abstract To establish lifelong, latent infection, herpesviruses circularize their linear, double-stranded, DNA genomes through an unknown mechanism. Kaposi's sarcoma (KS) herpesvirus (KSHV), a gamma herpesvirus, is tightly linked with KS, primary effusion lymphoma, and multicentric Castleman's disease. KSHV persists in latently infected cells as a multi-copy, extrachromosomal episome. Here, we show the KSHV genome rapidly circularizes following infection, and viral protein expression is unnecessary for this process. The DNA damage response (DDR) kinases, ATM and DNA-PKcs, each exert roles, and absence of both severely compromises circularization and latency. These deficiencies were rescued by expression of ATM and DNA-PKcs, but not catalytically inactive mutants. In contrast, γH2AX did not function in KSHV circularization. The linear viral genomic ends resemble a DNA double strand break, and non-homologous DNA end joining (NHEJ) and homologous recombination (HR) reporters indicate both NHEJ and HR contribute to KSHV circularization. Last, we show, similar to KSHV, ATM and DNA-PKcs have roles in circularization of the alpha herpesvirus, herpes simplex virus-1 (HSV-1), while γH2AX does not. Therefore, the DDR mediates KSHV and HSV-1 circularization. This strategy may serve as a general herpesvirus mechanism to initiate latency, and its disruption may provide new opportunities for prevention of herpesvirus disease.

Li, Shijun↗
DOE OSTI2021

Current status and future outlook for patient‐derived cancer models from a rare cancer research perspective

Abstract Rare cancers are a group of approximately 200 malignancies with extremely low incidences and with a wide variety of genotypes and phenotypes. Collectively, they are more common than any single malignancy. However, given the small numbers of individuals diagnosed with rare cancers, it is difficult to design clinical trials with sufficient patient numbers. Therefore, few effective anticancer drugs have been developed, and evidence‐based medicine is not always feasible for rare cancers. Consequently, their clinical outcomes are generally poorer. Cancer research requires adequate models that faithfully recapitulate molecular features and reproduce treatment responses of the original tumors. Such models allow us to focus on more efficacious drugs in the clinical studies. For rare cancers, patient‐derived cancer models are particularly important because the enrollment of sufficient patients is rarely attainable within a reasonable period of time. However, extremely few models are available for rare cancers. For example, cell lines and xenografts are available for only a limited number of histological subtypes of sarcomas; therefore, most sarcoma research is performed without such models, and a lack of adequate cancer models causes a lag in therapeutic development. The establishment of novel rare cancer models will dramatically facilitate rare cancer research and treatment development in the near future. This review focuses on the status of patient‐derived rare cancer models and discusses their pivotal problems and possibilities, using sarcomas as a representative rare cancer type. Multi‐institutional collaboration will help address the scarcity of patient‐derived rare cancer models.

Kondo, Tadashi↗
DOE OSTI2021

Chromosome 8 gain is associated with high-grade transformation in MPNST

One of the most common malignancies affecting adults with Neurofibromatosis type 1 (NF1) is the malignant peripheral nerve sheath tumor (MPNST), an aggressive and often fatal sarcoma which most often arises from within benign plexiform neurofibromas. Despite advances in our understanding of the pathobiology of MPNST, there are few effective therapeutic options, and no investigational agents have proven successful in clinical trials. To further understand the genomic heterogeneity of MPNST, and to generate a preclinical platform that encompasses this heterogeneity, we developed a collection of NF1-MPNST patient derived xenografts (PDX). These PDX were compared to the primary tumors from which they were derived using copy number analysis, whole exome and RNA sequencing. We identified chromosome 8 gain as a recurrent genomic event in MPNST and validated its occurrence by FISH in the PDX and parental tumors, in a validation cohort, and by single cell sequencing in the PDX. Finally, we show that chromosome 8 gain is associated with inferior overall survival in soft tissue sarcomas. Taken together, these data suggest that chromosome 8 gain is a critical event in MPNST pathogenesis, and may account for the aggressive nature and poor outcomes in this sarcoma subtype.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Development of a Novel Humanized Monoclonal Antibody to Secreted Frizzled-Related Protein-2 That Inhibits Triple-Negative Breast Cancer and Angiosarcoma Growth In Vivo

Background: We previously reported that secreted frizzled-related protein-2 (SFRP2) is expressed in a variety of tumors, including sarcoma and breast carcinoma, and stimulates angiogenesis and inhibits tumor apoptosis. Therefore, we hypothesized that a humanized SFRP2 monoclonal antibody (hSFRP2 mAb) would inhibit tumor growth. Methods: The lead hSFRP2 antibody was tested against a cohort of 22 healthy donors using a time course T-cell assay to determine the relative risk of immunogenicity. To determine hSFRP2 mAb efficacy, nude mice were subcutaneously injected with SVR angiosarcoma cells and treated with hSFRP2 mAb 4 mg/kg intravenously every 3 days for 3 weeks. We then injected Hs578T triple-negative breast cells into the mammary fat pad of nude mice and treated for 40 days. Control mice received an immunoglobulin (Ig) G1 control. The SVR and Hs578T tumors were then stained using a TUNEL assay to detect apoptosis. Results: Immunogenicity testing of hSFRP2 mAb did not induce proliferative responses using a simulation index (SI) ≥ 2.0 (p < 0.05) threshold in any of the healthy donors. SVR angiosarcoma tumor growth was inhibited in vivo, evidenced by significant tumor volume reduction in the hSFRP2 mAb-treated group, compared with controls (n = 10, p < 0.001). Likewise, Hs578T triple-negative breast tumors were smaller in the hSFRP2 mAb-treated group compared with controls (n = 10, p < 0.001). The hSFRP2 mAb treatment correlated with an increase in tumor cell apoptosis (n = 11, p < 0.05). Importantly, hSFRP2 mAb treatment was not associated with any weight loss or lethargy. Conclusion: We present a novel hSFRP2 mAb with therapeutic potential in breast cancer and sarcoma that has no effect on immunogenicity.

60 APPLIED LIFE SCIENCES↗