Radiation Biological Toximetry Using Circulating Cell-Free DNA (cfDNA) for Rapid Radiation/Nuclear Triage

Optimal triage biodosimetry would include risk stratification within minutes, and it would provide useful triage despite heterogeneous dosimetry, cytokine therapy, mixed radiation quality, race, and age. For regulatory approval, the U.S. Food and Drug Administration (FDA) Biodosimetry Guidance requires suitability for purpose and a validated species-independent mechanism. Circulating cell-free DNA (cfDNA) concentration assays may provide such triage information. To test this hypothesis, cfDNA concentrations were measured in unprocessed monkey plasma using a branched DNA (bDNA) technique with a laboratory developed test. Therefore, cfDNA concentration measurements are increasingly used in radiation oncology clinics to predict side effect risk. The cfDNA levels, along with hematopoietic parameters, were measured over a 7-day period in Rhesus macaques receiving total body radiation doses ranging from 1 to 6.5 Gy. Low-dose irradiation (0-2 Gy) was easily distinguished from high-dose whole-body exposures (5.5 and 6.5 Gy). Fold changes in cfDNA in the monkey model were comparable to those measured in a bone marrow transplant patient receiving a supralethal radiation dose, suggesting that the lethal threshold of cfDNA concentrations may be similar across species. Average cfDNA levels were 50 ± 40 ng/mL [±1 standard deviation (SD)] pre-irradiation, 120 ± 13 ng/mL at 1 Gy; 242 ± 71 ng/mL at 2 Gy; 607 ± 54 at 5.5 Gy; and 1585 ± 351 at 6.5 Gy (±1 SD). There was an exponential increase in cfDNA concentration with radiation dose. Comparison of the monkey model with the mouse model and the Guskova model, developed using Chernobyl responder data, further demonstrated correlation across species, supporting a similar mechanism of action. The test is available commercially in a Clinical Laboratory Improvement Amendments (CLIA) ready form in the U.S. and the European Union. The remaining challenges include developing methods for further simplification of specimen processing and assay evaluation, as well as more accurate calibration of the triage category with cfDNA concentration cutoffs.

Florida-California Cancer Research, Education and Engagement (CaRE2) Health Equity Center: Structure, Innovations, and Initial Outcomes

INTRODUCTION

The Florida-California Cancer Research, Education, and Engagement (CaRE2) Health Equity Center is a triad partnership committed to increasing institutional capacity for cancer disparity research, the diversity of the cancer workforce, and community empowerment. This article provides an overview of the structure, process innovations, and initial outcomes from the first 4 years of the CaRE2 triad partnership.

METHODS

CaRE2 serves diverse populations in Florida and California using a "molecule to the community and back" model. We prioritize research on the complex intersection of biological, environmental, and social determinants health, working together with scientific and health disparities communities, sharing expertise across institutions, bidirectional training, and community outreach. Partnership progress and outcomes were assessed using mixed methods and four Program Steering Committee meetings.

RESULTS

Research capacity was increased through development of a Living Repository of 81 cancer model systems from minority patients for novel cancer drug development. CaRE2 funded 15 scientific projects resulting in 38 publications. Workforce diversity entailed supporting 94 cancer trainees (92 URM) and 34 ESIs (32 URM) who coauthored 313 CaRE2-related publications and received 48 grants. Community empowerment was promoted via outreaching to more than 3000 individuals, training 145 community cancer advocates (including 28 Community Scientist Advocates), and publishing 10 community reports. CaRE2 members and trainees together have published 639 articles, received 61 grants, and 57 awards.

CONCLUSION

The CaRE2 partnership has achieved its initial aims. Infrastructure for translational cancer research was expanded at one partner institution, and cancer disparities research was expanded at the two cancer centers.

Circulating Cell-Free DNA Correlates with Body Integral Dose and Radiation Modality in Prostate Cancer

Purpose

The RadTox assay measures circulating cell-free DNA released in response to radiotherapy (RT)-induced tissue damage. The primary objectives for this clinical trial were to determine whether cell-free DNA numbers measured by the RadTox assay are (1) correlated with body integral dose, (2) lower with proton RT compared with photon RT, and (3) higher with larger prostate cancer RT fields.

Patients and Methods

Patients planned to receive proton or photon RT for nonmetastatic prostate cancer in the setting of an intact prostate or postprostatectomy were eligible for the trial. Plasma was collected pre-RT and at 5 additional daily collection points beginning 24 hours after the initiation of RT. Data from 54 evaluable patients were analyzed to examine any correlations among RadTox scores with body-integral dose, RT modality (photon versus proton), and RT field size (prostate or prostate bed versus whole pelvis).

Results

Body integral dose was significantly associated with the peak post-RT RadTox score (P = .04). Patients who received photon RT had a significant increase in peak post-RT RadTox score (P = .04), average post-RT RadTox score (P = .04), and day-2 RadTox score (all minus the pre-RT values for each patient) as compared with patients who received proton RT. Field size was not significantly associated with RadTox score.

Conclusion

RadTox is correlated with body integral dose and correctly predicts which patients receive proton versus photon RT. Data collection remains ongoing for patient-reported RT toxicity outcomes to determine whether RadTox scores are correlated with toxicity.

Concomitant Radiation Recall Dermatitis and Organizing Pneumonia following Breast Radiotherapy: A Case Report

Purpose

Radiation recall dermatitis (RRD) is a rare complication that occurs after completion of radiation therapy (RT) and initiation of a precipitating agent, most commonly chemotherapeutic medications. Various theories attempt to explain the mechanism, including activation of the body's inflammatory pathways through nonimmune activation. Likewise, radiation-induced organizing pneumonia (RIOP) is an infrequent but potentially life-threatening complication of RT that, while not fully understood, is suspected to be partly an autoimmune reaction.

Patient

We present the case of a 71-year-old female with a history of type 2 diabetes mellitus, hypothyroidism, interstitial cystitis, and osteoarthritis who presented with clinical stage T1N0M0 ER+/PR–/HER2– invasive ductal carcinoma of the lower outer quadrant of the left breast, for which she underwent left segmental mastectomy and sentinel lymph node biopsy followed by completion axillary lymph node dissection. Her final pathologic stage was T1N1M0.

Result

The patient developed RRD and later RIOP following receipt of radiation and chemotherapy, which resolved with steroid administration.

Conclusions

The rarity of both RRD and RIOP occurring in a patient, as in our case, suggests a shared pathophysiology behind these two complications. As both reactions involve some degree of inflammation and respond to corticosteroids, it seems likely that the etiologies of RRD and RIOP lie within the inflammatory pathway. However, further investigation should evaluate the frequency, duration, and triggering of concomitant RRD and RIOP.

Abstract A084: Personalized prediction of radiation sensitivity

Purpose/Objective: Patients of different races with similar cancers are often treated with radiation according to safety criteria largely collected from patients of European origin. However, even among those patients, toxicities are not predictable. Patients of African origin appear to have more severe skin radiation reactions, particularly Black women with breast cancer, than other populations. We have developed a technique using circulating cell-free DNA (cfDNA) that appears to predict toxicity in patients with otherwise similar radiation dosimetry, allowing for early intervention to prevent side effects (marketed as RadToxTM, DiaCarta, Inc.). Methods: Pre-clinical studies were performed in mice with white (BALB/c), brown (C3H/HeJ), or black (C57BL/6) fur. Radiation was delivered to the hind limb, and the skin reaction was evaluated. Blood was collected to evaluate changes in cfDNA as compared to severity of cutaneous toxicity. A phase I/II clinical study (n=54) was also performed to determine if plasma cfDNA measured early in a radiotherapy course can predict the subset of patients who experience grade 2 or higher radiotoxicity. Results: The most severe toxicity was seen in the C57BL/6 mice, and at similar doses the increase in cfDNA was higher than in the other two strains. Fifty-four patients were evaluable for the clinical study. Radiation significantly increased cfDNA on all days following the first radiation session. Acute maximum GI toxicity score, but not acute GU toxicity, was significantly correlated with cfDNA levels obtained on days 1, 2, 3, 4, and 5 of radiotherapy (p<0.005). Conclusions: Plasma cfDNA levels predicted the mouse strain that experienced more severe toxicity, and in a small study detected acute bowel toxicity. A larger study is needed to confirm the results and the value of the test for identifying patients who need special interventions to reduce toxicity. Further testing of this hypothesis is under evaluation in an NCI-funded multi-institutional study.

Citation Format: Natalie Lockney, Steven G Swarts, Jennifer Li, Christopher Morris, Randal Henderson, Steven B Zhang, Zhenhuan Zhang, Sadasivan Vidyasagar, Reshu Gupta, Katherine Casey-Sawicki, Robert Zlotecki, Paul Okunieff. Personalized prediction of radiation sensitivity [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A084.

Abstract A083: Detection of personalized oncogenic risk after genotoxic exposures

Purpose: Despite reduced sensitivity to sun exposure, many Black patients treated with ionizing radiation appear to experience increased skin toxicity as compared to White patients. The cause is unknown, yet some studies have suggested that DNA repair is reduced in these patients. Therefore, we developed a technology to examine organ-specific differences in mutation rate after irradiation. In this study, we demonstrate the feasibility of personalized quantitative measurements of single base errors in DNA using a saline skin swab after irradiation. We believe this technology will have the potential to identify patients at higher risk for skin toxicity and, therefore, for whom preventative measures are most important. Methods/Results: We have developed a method for quantification of point mutations using xeno-DNA clamps. This method exceeds the theoretical limit for quantitation of base errors using standard deep-gene sequencing by several orders of magnitude. It can be performed on an organ-specific basis with less than 1 ng of DNA (≈100 cells). We have developed both a mouse and a human clamp set. Measurements of mouse organs, including the liver, brain, skin, spleen, and small bowel, were performed before and at various times after irradiation (0.5 to 10 Gy). Human cell culture studies parallel the mouse studies, and human clinical trials are underway using cotton swabs of skin and oral mucosa. The brain is highly efficient at damage repair, whereas mature lymphocytes repair poorly; epithelial cells (GI and skin) have intermediate accumulation of mutations after irradiation. Mutation accumulation can be higher at a low dose and does not monotonically increase with dose. Conclusions: Our xeno-DNA clamp methodology can easily, inexpensively, and quantitatively measure incremental point changes in the non-coding silent DNA that makes up 98.5% of the human genome. The test is ready for clinical application and a clinical trial is beginning in Black and White patients with head and neck cancers. Preliminary data will be presented.

Citation Format: Paul Okunieff, Steven B Zhang, Zhenhuan Zhang, Steven G Swarts, Natalie A Lockney, Katherine Casey-Sawicki, Sadasivan Vidyasagar. Detection of personalized oncogenic risk after genotoxic exposures [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A083.

Single-Fraction Radiosurgery Using Conservative Doses for Brain Metastases: Durable Responses in Select Primaries With Limited Toxicity

BACKGROUND

Optimal doses for single-fraction stereotactic radiosurgery (SRS) in the treatment of brain metastases are not well established. Our institution utilized conservative dosing compared to maximum-tolerated doses from the Radiation Therapy Oncology Group 90-05 Phase I study.

OBJECTIVE

To report individual lesion control (LC) from conservative single-fraction doses and determine factors affecting LC.

METHODS

From 2003 to 2015, patients who underwent linear accelerator-based single-fraction SRS for cerebral/cerebellar metastases and receiving at least 1 follow-up magnetic resonance imaging (MRI) were identified. Lesion response was assessed by a size-based rating system and modified "Response Assessment in Neuro-Oncology Brain Metastases" (RANO-BM) criteria.

RESULTS

Among 188 patients with 519 lesions, median survival was 13.1 mo; median follow-up time with MRI was 9.6 mo per course. Median tumor-periphery dose was 15 Gy (range: 7.5-20.7). Median lesion volume was 0.5 cc and diameter was 9 mm (range: 2-45). Concordance between RANO-BM and size-based system was 93%. Crude 1-yr LC was 80%, 73%, 56%, and 38% for lesions 1 to 10, 11 to 20, 21 to 30, >31 mm, respectively. On multivariate analysis, increased size, melanoma and colorectal histology, and progression after whole brain radiation therapy predicted worse LC. When excluding lesions treated as a boost, dose was a significant predictor of LC in multivariate models (hazard ratio 0.89, P = .01). Symptomatic radiation necrosis occurred in 10 lesions in 10 patients.

CONCLUSION

Histology predicts LC after conservative SRS doses with evidence of a dose-response relationship. Conservative single-fraction SRS doses confer minimal toxicity and acceptable control in certain subgroups (breast cancer, <5 mm), with suboptimal control in larger lesions and in combination with whole brain radiation therapy.

Cellular senescence and radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis (RIPF) is a serious treatment complication that affects about 9%-30% cancer patients receiving radiotherapy for thoracic tumors. RIPF is characterized by progressive and irreversible destruction of lung tissues and deterioration of lung function, which can compromise quality of life and eventually lead to respiratory failure and death. Unfortunately, the mechanisms by which radiation causes RIPF have not been well established nor has an effective treatment for RIPF been developed. Recently, an increasing body of evidence suggests that induction of senescence by radiation may play an important role in RIPF and clearance of senescent cells (SnCs) with a senolytic agent, small molecule that can selectively kill SnCs, has the potential to be developed as a novel therapeutic strategy for RIPF. This review discusses some of these new findings to promote further study on the role of cellular senescence in RIPF and the development of senolytic therapeutics for RIPF.

Radiation-induced tumor immunity in patients with non-small cell lung cancer

Background

Radiation‐induced tumor immunity (RITI) influences primary tumor growth and development of metastases in preclinical cancer models with conventional radiotherapy. Antigen‐specific immune responses have also been shown for prostate cancer treated with radiotherapy. We examined whether RITI can be induced in patients with non‐small cell lung cancer (NSCLC) following proton radiotherapy.

Methods

Pre‐ and post‐radiotherapy plasma samples from 26 patients with nonmetastatic NSCLC who received radiotherapy between 2010 and 2012 were evaluated by western blotting for IgG and IgM bands to assess RITI response to tumor antigens from lung cancer cell lines. Statistical analysis was used to evaluate any correlation among IgG or IgM and clinical outcomes.

Results

Twenty‐one patients received proton therapy at 2 GyRBE/fraction (n = 17) or 6–12 Gy/fraction (n = 4); five received photon therapy at 2–2.5 GyRBE/fraction. Compared with the pretreatment baseline, new IgG or IgM binding was detected in 27% and 50% of patients, respectively. New IgG bands were detected in the 25–37 kD, 50–75 kD, and 75–100 kD ranges. New IgM bands were detected in the 20–25 kD, 25–37 kD, 37–50 kD, 50–75 kD, and 75–100 kD ranges. There was no difference in IgG and/or IgM RITI response in patients treated with photons versus protons, or in patients who received SBRT compared to standard fractionation (P > 0.05). There was no difference in overall survival, metastasis‐free survival, or local control based on IgG and/or IgM RITI response (P > 0.05).

Conclusion

RITI can be induced in patients with NSCLC through upregulated IgG and/or IgM. RITI response was not associated with proton versus photon therapy or with clinical outcomes in this small cohort and should be examined in a larger cohort in future studies.

Hypofractionated Stereotactic Radiotherapy for Non-breast or Prostate Cancer Oligometastases: A Tail of Survival Beyond 10 Years

Purpose and Objective(s): We sought to analyze the long-term follow-up of patients treated with hypofractionated, stereotactic radiotherapy (HSRT) for oligometastases from malignancies other than breast or prostate cancer. Materials and Methods: From 2001 to 2006, 82 cancer patients with 1-5 radiographically apparent metastatic lesions (in 1-3 organs) from primary sites other than breast or prostate cancer, were enrolled on a prospective study of HSRT. Freedom from widespread metastasis (FFWM) was defined from date of enrollment until death, an event (i.e., widespread distant metastasis not amenable to local therapy), or last radiographic study. Local recurrence was scored as an event if pathologically confirmed or if a treated lesion increased by ≥20% using RECIST criteria. Prognostic variables were assessed using Cox regression analysis. Results: The mean age was 61 ± 11 years, with a male to female ratio of 46:36. The most common metastatic sites were liver (50%), lung (48%), thoracic lymph nodes (18%), and bone (5%). Sixty-one patients (74%) had 1 involved organ and 18 (22%) had 1 lesion treated. The preferred dose-fractionation scheduled was 50 Gy in 10 fractions (52 patients). The median follow-up was 1.7 years. Eleven patients lived >5 years, and 6 lived >10 years. The 5-year OS, PFS, FFWM, and LC rates were 13.4, 7.3, 18.3, and 63.4%, and the 10-years OS, PFS, FFWM, and patient LC rates were 7.3, 6.1, 13.4, and 62.2%, respectively. A greater net gross tumor volume (GTV) was significantly adverse for OS (p < 0.01) and LC (p < 0.01). For FFWM, net GTV was not a significant factor (p = 0.14). Four patients remain alive at >13 years from enrollment and treatment, without evidence of active disease. Conclusion: A small subset of select non-breast, non-prostate cancer patients with limited metastasis treated with HSRT are long-term survivors. Net GTV is a significant factor for tumor control and survival. Further research is needed to help better select patients most likely to benefit from local therapy for metastatic disease.

An in-silico quality assurance study of contouring target volumes in thoracic tumors within a cooperative group setting

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We aimed at quantifying inter-observer Pancoast tumors delineation variability.

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Experts’ delineations were used to define ground truth.

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Other observers’ delineations were compared against ground truth.

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High degree of variability was noted for most target volumes except GTV_P.

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This unveils potentials for protocol modification for future IMRT studies.

Introduction

Target delineation variability is a significant technical impediment in multi-institutional trials which employ intensity modulated radiotherapy (IMRT), as there is a real potential for clinically meaningful variances that can impact the outcomes in clinical trials. The goal of this study is to determine the variability of target delineation among participants from different institutions as part of Southwest Oncology Group (SWOG) Radiotherapy Committee’s multi-institutional in-silico quality assurance study in patients with Pancoast tumors as a “dry run” for trial implementation.

Methods

CT simulation scans were acquired from four patients with Pancoast tumor. Two patients had simulation 4D-CT and FDG-FDG PET-CT while two patients had 3D-CT and FDG-FDG PET-CT. Seventeen SWOG-affiliated physicians independently delineated target volumes defined as gross primary and nodal tumor volumes (GTV_P & GTV_N), clinical target volume (CTV), and planning target volume (PTV).

Six board-certified thoracic radiation oncologists were designated as the ‘Experts’ for this study. Their delineations were used to create a simultaneous truth and performance level estimation (STAPLE) contours using ADMIRE software (Elekta AB, Sweden 2017). Individual participants’ contours were then compared with Experts’ STAPLE contours.

Results

When compared to the Experts’ STAPLE, GTV_P had the best agreement among all participants, while GTV_N showed the lowest agreement among all participants. There were no statistically significant differences in all studied parameters for all TVs for cases with 4D-CT versus cases with 3D-CT simulation scans.

Conclusions

High degree of inter-observer variation was noted for all target volume except for GTV_P, unveiling potentials for protocol modification for subsequent clinically meaningful improvement in target definition. Various similarity indices exist that can be used to guide multi-institutional radiotherapy delineation QA credentialing.

A novel approach for fast detection of sepsis with Gram-negative bacterial infection

Sepsis, a life-threatening systemic infection, requires quick treatment. Gram-negative bacteria (GNB) are the major causative pathogens and their endotoxin can be a surrogate biomarker for diagnosis. We explored a fast identification of GNB by first culturing blood to increase endotoxin levels and then detecting endotoxin by Tachypleus amebocyte lysate (TAL) with kinetic turbidimetric assay (KT-TAL). Heating samples could significantly increase the endotoxin released from GNB; speed and time of centrifugation, and sample dilution could affect the endotoxin results. At a high GNB load, endotoxin was detected 3 h after culture, 6.5 h earlier than the BD BACTEC blood culture system detecting GNB. At a low GNB load, endotoxin was detected at 9 h after culture, 13 h earlier than by the BD BACTEC system. In a sepsis patient with Acinetobacter baumannii, we detected endotoxin at 12 h after culture, while the BD BACTEC system needed 28.5 h for detection, allowing physicians an earlier decision on appropriate treatment.

Stereotactic Ablative Body Radiotherapy for Primary Non-Small-Cell Lung Cancer: Achieving Local Control with a Lower Biologically Effective Dose

We conducted a retrospective study of stereotactic ablative radiotherapy (SABR) for 94 patients with non-small-cell lung cancer at our institution. The patients were treated with either 50 Gy in five treatments or 48 Gy in four treatments, corresponding to biologically effective doses (BED) of 100 Gy or 105.6 Gy, respectively. The results demonstrate that, with relatively low BEDs, we can achieve excellent local control with minimal toxicity.

Triptolide mitigates radiation-induced pneumonitis via inhibition of alveolar macrophages and related inflammatory molecules

Ionizing radiation-induced pulmonary injury is a major limitation of radiotherapy for thoracic tumors. We have demonstrated that triptolide (TPL) could alleviate IR-induced pneumonia and pulmonary fibrosis. In this study, we explored the underlying mechanism by which TPL mitigates the effects of radiotoxicity. The results showed that:

(1) Alveolar macrophages (AMs) were the primary inflammatory cells infiltrating irradiated lung tissues and were maintained at a high level for at least 17 days, which TPL could reduce by inhibiting of the production of macrophage inflammatory protein-2 (MIP-2) and its receptor CXCR2.

(2) Stimulated by the co-cultured irradiated lung epithelium, AMs produced a panel of inflammative molecules (IMs), such as cytokines (TNF-α, IL-6, IL-1α, IL-1β) and chemokines (MIP-2, MCP-1, LIX). TPL-treated AMs could reduce the production of these IMs. Meanwhile, AMs isolated from irradiated lung tissue secreted significantly high levels of IMs, which could be dramatically reduced by TPL.

(3) TPL suppressed the phagocytosis of AMs as well as ROS production.

Our results indicate that TPL mitigates radiation-induced pulmonary inflammation through the inhibition of the infiltration, IM secretion, and phagocytosis of AMs.

Report from the SWOG Radiation Oncology Committee: Research Objectives Workshop 2017

The Radiation Therapy Committee of SWOG periodically evaluates its strategic plan in an effort to maintain a current and relevant scientific focus, and to provide a standard platform for future development of protocol concepts. Participants in the 2017 Strategic Planning Workshop included leaders in cancer basic sciences, molecular theragnostics, pharmaceutical and technology industries, clinical trial design, oncology practice, and statistical analysis. The committee discussed high-priority research areas, such as optimization of combined modality therapy, radiation oncology-specific drug design, identification of molecular profiles predictive of radiation-induced local or distant tumor responses, and methods for normal tissue-specific mitigation of radiation toxicity. The following concepts emerged as dominant questions ready for national testing: (i) what is the role of radiotherapy in the treatment of oligometastatic, oligorecurrent, and oligoprogressive disease? (ii) How can combined modality therapy be used to enhance systemic and local response? (iii) Can we validate and optimize liquid biopsy and other biomarkers (such as novel imaging) to supplement current response criteria to guide therapy and clinical trial design endpoints? (iv) How can we overcome deficiencies of randomized survival endpoint trials in an era of increasing molecular stratification factors? And (v) how can we mitigate treatment-related side effects and maximize quality of life in cancer survivors? The committee concluded that many aspects of these questions are ready for clinical evaluation and example protocol concepts are provided that could improve rates of cancer cure and quality of survival. Clin Cancer Res; 24(15); 3500-9. ©2018 AACR.

Stereotactic Body Radiotherapy for Lung Metastases from Colorectal Cancer: Prognostic Factors for Disease Control and Survival

OBJECTIVES

To evaluate disease control and survival after stereotactic body radiotherapy (SBRT) for lung metastases from colorectal cancer and to identify prognostic factors after treatment.

METHODS

Patients with metastatic colorectal cancer to the lungs treated with SBRT from 2002 to 2013 were identified from a prospectively maintained database. Patients may have received prior systemic therapy, radiotherapy to nonthoracic sites and/or resection of thoracic and/or nonthoracic metastases. Endpoints were timed from end of SBRT and included overall survival (OS), progression-free survival, distant metastases-free survival, and local failure-free survival. Univariate and multivariate analysis using Cox proportional hazard modeling was used to identify prognostic factors.

RESULTS

Sixty-five patients were identified. Before SBRT, 69.2% and 33.8% of patients received systemic therapy and lung-directed local therapy, respectively, for metastatic disease. At the time of SBRT, 64.6% had lung-only involvement. Median survivals were: OS of 20.3 months (95% confidence intervals [CI], 15.9-27.0 mo), progression-free survival of 5.7 months (95% CI, 3.2-7.0 mo), distant metastases-free survival of 5.8 months (95% CI, 3.2-7.6 mo), and local failure-free survival of 15.4 months (95% CI, 8.5-21.1 mo). Nearly all (98%) patients developed distant progression. Extra lung and liver involvement at the time of initial metastases (hazard ratios [HR] 2.10) and extra lung involvement at SBRT (HR 2.67) were the only independent predictors of OS. Net gross target volume of >14.1 mL (HR 2.49) was the only independent predictor of local failure-free survival.

CONCLUSIONS

Reasonable survival and local control can be achieved with SBRT. We identified several prognostic factors testable in future prospective trials that may help improve patient selection.

Ensuring sample quality for blood biomarker studies in clinical trials: a multicenter international study for plasma and serum sample preparation

Background

Sample quality is critical for biomarker detection in oncology, and platelet degradation and contamination in plasma have a remarkable impact on the ability to accurately quantify many blood-based biomarkers. Platelet factor 4 (PF4) can be used as an indicator to monitor sample quality. This multicenter study aimed to determine the impact of critical components of the blood sample handling process on platelet degradation/contamination and to establish an optimal method for collecting platelet-poor plasma samples.

Methods

At each of six participating centers, blood samples were drawn from 12-13 healthy volunteers. Serum and plasma samples were prepared from whole blood samples using nine different methods that have been commonly used in ongoing multicenter trials. PF4 levels in the prepared samples were measured by enzyme-linked immunosorbent assay (ELISA). Paired t-tests were used for statistical analysis.

Results

Blood samples were collected from 74 subjects enrolled in six centers. PF4 levels were significantly higher in serum samples than in plasma samples (P<0.001), in plasma samples from blood that sat at room temperature for 5 minutes (P=0.021), in plasma samples prepared at an insufficient centrifugal force (P<0.001), and in plasma samples prepared from blood that sat for longer than 4 hours on ice (P=0.001). For each method, the PF4 levels did not differ significantly among the centers or between Chinese and American subjects. The methods that resulted in normal levels of PF4 involved keeping blood samples on ice for 30 minutes to <4 hours and centrifugation at 2,500-3,000 ×g for 30 min.

Conclusions

This multicenter study evaluated multiple blood sample handling conditions for minimizing platelet degradation during plasma serum preparation and determined an optimal method for preparing platelet-poor plasma. The findings of this study can be applied in future blood biomarker studies.

Glucose enhances rotavirus enterotoxin-induced intestinal chloride secretion

Rotavirus causes severe diarrhea in small children and is typically treated using glucose-containing oral rehydration solutions; however, glucose may have a detrimental impact on these patients, because it increases chloride secretion and presumably water loss. The rotavirus enterotoxin nonstructural protein 4 (NSP4) directly inhibits glucose-mediated sodium absorption. We examined the effects of NSP4 and glucose on sodium and chloride transport in mouse small intestines and Caco-2 cells. Mouse small intestines and Caco-2 cells were incubated with NSP4_114-135 in the presence/absence of glucose. Absorption and secretion of sodium and chloride, fluid movement, peak amplitude of intracellular calcium fluorescence, and expression of Ano1 and sodium-glucose cotransporter 1 were assessed. NHE3 activity increased, and chloride secretory activity decreased with age. Net chloride secretion increased, and net sodium absorption decreased in the intestines of 3-week-old mice compared to 8-week-old mice with NSP4. Glucose increased NSP4-stimulated chloride secretion. Glucose increased NSP4-stimulated increase in short-circuit current measurements (I _sc) and net chloride secretion. Ano1 cells with siRNA knockdown showed a significant difference in I _sc in the presence of NSP4 and glucose without a significant difference in peak calcium fluorescence intracellular when compared to non-silencing (N.S.) cells. The failure of glucose to stimulate significant sodium absorption was likely due to the inhibition of sodium-hydrogen exchange and sodium-glucose cotransport by NSP4. Since glucose enhances intestinal chloride secretion and fails to increase sodium absorption in the presence of NSP4, glucose-based oral rehydration solutions may not be ideal for the management of rotaviral diarrhea.

Comparison of three different methods for the detection of circulating tumor cells in mice with lung metastasis

Circulating tumor cells (CTCs) represent the key step of cancer cell dissemination. The alteration of CTCs correlates with the treatment outcome and prognosis. To enrich and identify CTCs from billions of blood cells renders a very challenging task, which triggers development of several methods, including lysis of RBC plus negative or positive enrichment using antibodies, and filter membrane or spiral microfluidics to capture CTCs. To compare the advantages of different enrichment methods for CTCs, we utilized the 4T1 breast cancer cells transfected with both green fluorescent protein (GFP) and luciferase to trace CTCs in the experimental lung metastasis model. Three methods were used to detect CTCs at the same time: bioluminescence assay, smearing method, and membrane filter method. The in vivo alive mouse imaging was used to dynamically monitor the growth of lung metastases. The sensitivity and accuracy of three detection methods were compared side-by-side. Our results showed that 1) the sensitivity of bioluminescence assay was the highest, but there was no information of CTC morphology; 2) the smearing method and membrane filter method could observe the detail of CTC morphology, such as in single or in cluster, while their sensitivity was lower than bioluminescence assay; 3) A dynamic observation at a 7-day intervals, the lung metastatic cancer grew at a log speed, while CTCs were increased at a low speed. This might be due to the activated immune cells eliminating the CTCs at a speed much faster than CTCs were generated. This comparison of three CTC detection methods in mouse model suggests that bioluminescence assay could be used in quantitative study of the effect of certain agent on the suppression of CTCs, while GFP-based morphological assays could be used to study the dissemination mechanism of CTCs. The combination of both bioluminescence assay and GFP-based assay would generate more information for quantity and quality of CTCs.

TLR9 mediated regulatory B10 cell amplification following sub-total body irradiation: Implications in attenuating EAE

Autoimmunity and inflammation are controlled in part by regulatory B (Breg) cells, including the recently identified IL-10-competent B10 cell subset that represents 1%-3% of mouse spleen B cells. In this study, the influence of irradiation on Breg/B10 cell generation and IL-10 production mediated by TLR9 signaling pathways was investigated. Spleen and peritoneal cavity Breg/B10 cell frequencies were significantly expanded three weeks after sub-total body irradiation (sub-TBI, 5Gy or 10Gy) in adult male wild type (WT) C57BL/6(B6) mice but not in TLR9^-/- mice. TLR9 agonist ODN1826 stimulation in vitro for 5h induced more B10 cells to express cytoplasmic IL-10 in sub-TBI WT mice than in TLR9^-/- mice. Prolonged ODN1826 stimulation (48h) induced additional spleen CD19^hiCD5⁺CD1d^hi B cells to express IL-10. TLR9-dependent signaling molecules, MyD88, TRAF6 and IRF8 are involved in sub-TBI induced Breg/B10 cells development and expansion. Furthermore, using a mouse model for multiple sclerosis, we show here that sub-TBI induced Breg/B10 cells dramatically inhibit disease onset and severity when transferred into mice with established experimental autoimmune encephalomyelitis (EAE). Adoptively transferred sub-TBI induced Breg cells significantly suppress inflammatory T cell responses of TH17 and TH1 types in EAE mice. In conclusion, sub-TBI can drive Breg/B10 cell development and expansion, which could be used as a novel tool for suppressing undesirable immunity. The ex vivo expansion and reinfusion of autologous Breg/B10 cells may provide a novel and effective in vivo treatment for severe autoimmune diseases that are resistant to current therapies.

Stereotactic body radiation therapy for oligoprogression of metastatic disease from gastrointestinal cancers: A novel approach to extend chemotherapy efficacy

Chemotherapy and targeted therapies are effective palliative options for numerous unresectable or metastatic cancers. However, treatment resistance inevitably develops leading to mortality. In a subset of patients, systemic therapy appears to control the majority of tumors leaving 5 or less to progress, a phenomenon described as oligoprogression. Reasoning that the majority of lesions remain responsive to ongoing systemic chemotherapy, we hypothesized that local treatment of the progressing lesions would confer a benefit. The present study describes the cases of 5 patients whose metastatic disease was largely controlled by chemotherapy. The oligoprogressive lesions (≤5) were treated with stereotactic body radiotherapy (SBRT), justifying continued use of an effective systemic regimen. A total of 5 patients with metastatic disease on chemotherapy, with ≤5 progressing lesions amenable to SBRT, were treated with ablative intent. Primary tumor site and histology were as follows: 2 with metastatic colon adenocarcinoma, 2 with metastatic rectal adenocarcinoma and 1 with metastatic pancreatic adenocarcinoma. Imaging was performed prior to SBRT and every 3 months after SBRT. In total, 4 out of the 5 patients achieved disease control for >7 months with SBRT, without changing chemotherapy regimen. The median time to chemotherapy change was 9 months, with a median follow-up time of 9 months. The patient who failed to respond developed progressive disease outside of the SBRT field at 3 months. In conclusion, the addition of SBRT to chemotherapy is an option for the overall systemic control of oligoprogressive disease.

An amino acid-based oral rehydration solution (AA-ORS) enhanced intestinal epithelial proliferation in mice exposed to radiation

Destruction of clonogenic cells in the crypt following irradiation are thought to cause altered gastrointestinal function. Previously, we found that an amino acid-based oral rehydration solution (AA-ORS) improved gastrointestinal function in irradiated mice. However, the exact mechanisms were unknown. Electrophysiology, immunohistochemistry, qPCR, and Western blot analysis were used to determine that AA-ORS increased proliferation, maturation, and differentiation and improved electrolyte and nutrient absorption in irradiated mice. A single-hit, multi-target crypt survival curve showed a significant increase in crypt progenitors in irradiated mice treated with AA-ORS for six days (8.8 ± 0.4) compared to the saline-treated group (6.1 ± 0.3; P < 0.001) without a change in D₀ (4.8 ± 0.1 Gy). The D_q values increased from 8.8 ± 0.4 Gy to 10.5 ± 0.5 Gy with AA-ORS treatment (P < 0.01), indicating an increased radiation tolerance of 1.7 Gy. We also found that AA-ORS treatment (1) increased Lgr5⁺, without altering Bmi1 positive cells; (2) increased levels of proliferation markers (Ki-67, p-Erk, p-Akt and PCNA); (3) decreased apoptosis markers, such as cleaved caspase-3 and Bcl-2; and (4) increased expression and protein levels of NHE3 and SGLT1 in the brush border membrane. This study shows that AA-ORS increased villus height and improved electrolyte and nutrient absorption.

Triptolide mitigates radiation-induced pulmonary fibrosis via inhibition of axis of alveolar macrophages-NOXes-ROS-myofibroblasts

PURPOSE

IR-induced pulmonary fibrosis is one of the most severe late complications of radiotherapy for lung cancer. It is urgently needed to discover a new drug for anti-IR lung fibrosis. Our previous studies have indicated that TPL exhibits both anti-IR lung fibrosis and anti-tumor activities. To reveal the mechanism of TPL on anti-IR lung fibrosis, alveolar macrophages (AMs) were examined for TPL effect on their axis of Nicotinamide adenine dinucleotide phosphate oxidase-reactive oxygen species (NOXes-ROS) and myofibroblast activation.

METHODS AND MATERIALS

The fibrosis-prone C57BL/6 mice were irradiated with 15 Gy on whole chest, then one day later, mice were treated without or with TPL (i.v. 0.25 mg/kg, qod for 1 month). The AMs were collected from bronchoalveolar lavage fluids and studied for the production of ROS and the levels of NOXes. The effect of AMs on myofibroblast activation as labeled with F4/80 or α-SMA (α-smooth muscle actin) were examined using flow cytometry, Western blotting, or immunohistochemical staining.

RESULTS

TPL effectively reduced the IR-induced lung fibrosis as evidenced by the less myofibroblasts, less collagen deposit and less ROS in the IR-lung tissues. We found that ROS which responsible for myofibroblasts activation was mainly from AMs and was NOX2 and NOX4 dependent. TPL significantly reduced the infiltrated AMs in IR-lung tissues, and in addition, down regulated the level of NOX2 and NOX4 in AMs both in vitro and in vivo. Furthermore, by inhibiting NOXes dependent ROS in AMs, TPL deprived AMs' paracrine activation of myofibroblasts.

CONCLUSIONS

Our work demonstrated that the anti-fibrotic effect of TPL on IR-induced pulmonary fibrosis was related to its inhibition on the axis of alveolar macrophages-NOXes-ROS-myofibroblasts.

Triptolide Mitigates Radiation-Induced Pulmonary Fibrosis

Triptolide (TPL) may mitigate radiation-induced late pulmonary side effects through its inhibition of global pro-inflammatory cytokines. In this study, we evaluated the effect of TPL in C57BL/6 mice, the animals were exposed to radiation with vehicle (15 Gy), radiation with TPL (0.25 mg/kg i.v., twice weekly for 1, 2 and 3 months), radiation and celecoxib (CLX) (30 mg/kg) and sham irradiation. Cultured supernatant of irradiated RAW 264.7 and MLE-15 cells and lung lysate in different groups were enzyme-linked immunosorbent assays at 33 h. Respiratory rate, pulmonary compliance and pulmonary density were measured at 5 months in all groups. The groups exposed to radiation with vehicle and radiation with TPL exhibited significant differences in respiratory rate and pulmonary compliance (480 ± 75/min vs. 378 ± 76/min; 0.6 ± 0.1 ml/cm H2O/p kg vs. 0.9 ± 0.2 ml/cm H2O/p kg). Seventeen cytokines were significantly reduced in the lung lysate of the radiation exposure with TPL group at 5 months compared to that of the radiation with vehicle group, including profibrotic cytokines implicated in pulmonary fibrosis, such as IL-1β, TGF- β1 and IL-13. The radiation exposure with TPL mice exhibited a 41% reduction of pulmonary density and a 25% reduction of hydroxyproline in the lung, compared to that of radiation with vehicle mice. The trichrome-stained area of fibrotic foci and pathological scaling in sections of the mice treated with radiation and TPL mice were significantly less than those of the radiation with vehicle-treated group. In addition, the radiation with TPL-treated mice exhibited a trend of improved survival rate compared to that of the radiation with vehicle-treated mice at 5 months (83% vs. 53%). Three radiation-induced profibrotic cytokines in the radiation with vehicle-treated group were significantly reduced by TPL treatment, and this partly contributed to the trend of improved survival rate and pulmonary density and function and the decreased severity of pulmonary fibrosis at 5 months. Our findings indicate that TPL could be a potential new agent to mitigate radiation-induced pulmonary fibrosis.

Performance of the HPV-16 L1 methylation assay and HPV E6/E7 mRNA test for the detection of squamous intraepithelial lesions in cervical cytological samples

HPV-16 L1 methylation and E6/E7 mRNA have suggested that they had close relationship with cervical neoplastic progression. This study aimed to evaluate the clinical performance of the HPV-16 L1 methylation assay and E6/E7 mRNA test for detecting high-grade cervical lesions (CIN2+). A total of 81 women with liquid-based cytology (LBC) samples, histological results, and positive HPV-DNA test for HPV type 16 only were included in this study. HPV-16 L1 methylation and E6/E7 mRNA levels were measured using methylation-sensitive high resolution melting (MS-HRM) analysis and Quantivirus®HPV E6/E7 RNA 3.0 assay (bDNA), respectively, in the same residue of LBC samples. The current date showed a positive correlation between the HPV-16 L1 methylation and the E6/E7 mRNA levels. The L1 methylation and mRNA levels both increased with disease severity. The mRNA test method showed higher sensitivity and NPV (98.0 and 91.7% vs. 89.8 and 80.8%), while lower specificity and PPV (34.4 and 69.6% vs. 65.6 and 80.0%), than the L1 methylation assay for detecting histology-confirmed CIN2+. When using the detection method of mRNA test combined with L1 methylation assay, we obtained a sensitivity of 89.8% and a specificity of 71.9%. These findings suggest that assessment of HPV-16 L1 methylation testing combined with E6/E7 mRNA testing may be a promising method for the triage of women with HPV type 16 only.

PicoGreen assay of circular DNA for radiation biodosimetry

We developed a simple, rapid and quantitative assay using the fluorescent probe PicoGreen to measure the concentration of ionizing radiation-induced double-stranded DNA (dsDNA) in mouse plasma, and we correlated this concentration with the radiation dose. With 70 μl of blood obtained by fingerstick, this 30 min assay reduces protein interference without extending sample processing time. Plasma from nonirradiated mice (BALB/c and NIH Swiss) was pooled, diluted and spiked with dsDNA to establish sensitivity and reproducibility of the assay to quantify plasma dsDNA. The assay was then used to directly quantify dsDNA in plasma at 0-48 h after mice received 0-10 Gy total-body irradiation (TBI). There are three optimal conditions for this assay: 1:10 dilution of plasma in water; 1:200 dilution of PicoGreen reagent in water; and calibration of radiation-induced dsDNA concentration through a standard addition method using serial spiking of samples with genomic dsDNA. Using the internal standard calibration curve of the spiked samples method, the signal developed within 5 min, exhibiting a linear signal (r(2) = 0.997). The radiation-induced elevation of plasma DNA in mice started at 1-3 h, peaked at 9 h and gradually returned to baseline at 24 h after TBI (6 Gy). DNA levels in plasma collected from mice 9 h after 0-10 Gy TBI correlated strongly with dose (r(2) = 0.991 and 0.947 for BALB/c and NIH Swiss, respectively). Using the PicoGreen assay, we observed a radiation dose-dependent response in extracellular plasma DNA 9 h after irradiation with an assay time ≤ 30 min.

Design and synthesis of isosteviol triazole conjugates for cancer therapy

One of the keys for successfully developing drugs against the broad spectrum of cancer cell types is structural diversity. In the current study, we focused on a family of isosteviol derivatives as potential novel antitumor agents. Isosteviol is a tetracyclic diterpenoid obtained by acid hydrolysis of steviol glycoside extracts isolated from abundant Stevia rebaudiana plants. In this work, we have designed and synthesized a panel of isosteviol triazole conjugates using "click" chemistry methodology. Evaluation of these compounds against a series of cancer cell lines derived from primary and metastatic tumors demonstrated that these conjugates exhibit cytotoxic activities with IC50 in the low μM range. In addition, their anti-proliferative activities are cancer cell type specific. Taken together, our studies underscore the importance of structural diversity in achieving cancer cell type specific drug development.

A basic fibroblast growth factor analog for protection and mitigation against acute radiation syndromes

The effects of fibroblast growth factors and their potential as broad-spectrum agents to treat and mitigate radiation injury have been studied extensively over the past two decades. This report shows that a peptide mimetic of basic fibroblast growth factor (FGF-P) protects and mitigates against acute radiation syndromes. FGF-P attenuates both sepsis and bleeding in a radiation-induced bone marrow syndrome model and reduces the severity of gastrointestinal and cutaneous syndromes; it should also mitigate combined injuries. FGF-2 and FGF-P induce little or no deleterious inflammation or vascular leakage, which distinguishes them from most other growth factors, angiogenic factors, and cytokines. Although recombinant FGFs have proven safe in several ongoing clinical trials, they are expensive to synthesize, can only be produced in limited quantity, and have limited shelf life. FGF-P mimics the advantageous features of FGF-2 without these disadvantages. This paper shows that FGF-P not only has the potential to be a potent yet safe broad-spectrum medical countermeasure that mitigates acute radiotoxicity but also holds promise for thermal burns, ischemic wound healing, tissue engineering, and stem-cell regeneration.

An amino acid mixture mitigates radiation-induced gastrointestinal toxicity

Electrolyte and nutrient absorption occur in villous epithelial cells. Radiation often results in reduced electrolyte and nutrient absorption, which leads to gastrointestinal toxicity. Therefore, the authors studied: (1) radiation-induced changes in glucose and amino acid absorption across ileal tissues and (2) the effect of amino acid mixtures on absorptive capacity. NIH Swiss mice were irradiated (0, 1, 3, 5, or 7 Gy) using a ¹³⁷Cs source at 0.9 Gy min⁻¹. Transepithelial short circuit current (I(sc)), dilution potential, and isotope flux determinations were made in Ussing chamber studies and correlated to plasma endotoxin and IL-1β levels. Amino acids that increased electrolyte absorption and improved mucosal barrier functions were used to create a mitigating amino acid mixture (MAAM). The MAAM was given to mice via gastric gavage; thereafter, body weight and survival were recorded. A significant decrease in basal and glucose-stimulated sodium absorption occurred after 0, 1, 3, 5, and 7 Gy irradiation. Ussing chamber studies showed that paracellular permeability increased following irradiation and that the addition of glucose resulted in a further increase in permeability. Following irradiation, certain amino acids manifested decreased absorption, whereas others were associated with increased absorption. Lysine, aspartic acid, glycine, isoleucine, threonine, tyrosine, valine, tryptophan, and serine decreased plasma endotoxins were selected for the MAAM. Mice treated with the MAAM showed increased electrolyte absorption and decreased paracellular permeability, IL-1β levels, and plasma endotoxin levels. Mice treated with MAAM also had increased weight gain and better survival following irradiation. The MAAM has immediate potential for use in mitigating radiation-induced acute gastrointestinal syndrome.

Mitochondrial DNA and functional investigations into the radiosensitivity of four mouse strains

We investigated whether genetic radiosensitivity-related changes in mtDNA/nDNA ratios are significant to mitochondrial function and if a material effect on mtDNA content and function exists. BALB/c (radiosensitive), C57BL/6 (radioresistant), and F1 hybrid mouse strains were exposed to total body irradiation. Hepatic genomic DNA was extracted, and mitochondria were isolated. Mitochondrial oxygen consumption, ROS, and calcium-induced mitochondrial swelling were measured. Radiation influenced strain-specific survival in vivo. F1 hybrid survival was influenced by maternal input. Changes in mitochondrial content corresponded to survival in vivo among the 4 strains. Calcium-induced mitochondrial swelling was strain dependent. Isolated mitochondria from BALB/c mice were significantly more sensitive to calcium overload than mitochondria from C57BL/6 mice. Maternal input partially influenced the recovery effect of radiation on calcium-induced mitochondrial swelling in F1 hybrids; the hybrid with a radiosensitive maternal lineage exhibited a lower rate of recovery. Hybrids had a survival rate that was biased toward maternal input. mtDNA content and mitochondrial permeability transition pores (MPTP) measured in these strains before irradiation reflected a dominant input from the parent. After irradiation, the MPTP opened sooner in radiosensitive and hybrid strains, likely triggering intrinsic apoptotic pathways. These findings have important implications for translation into predictors of radiation sensitivity/resistance.