Whole Abdominal Irradiation Research Articles

Microbiota-derived I3A protects the intestine against radiation injury by activating AhR/IL-10/Wnt signaling and enhancing the abundance of probiotics

ABSTRACT The intestine is prone to radiation damage in patients undergoing radiotherapy for pelvic tumors. However, there are currently no effective drugs available for the prevention or treatment of radiation-induced enteropathy (RIE). In this study, we aimed at investigating the impact of indole-3-carboxaldehyde (I3A) derived from the intestinal microbiota on RIE. Intestinal organoids were isolated and cultivated for screening radioprotective tryptophan metabolites. A RIE model was established using 13 Gy whole-abdominal irradiation in male C57BL/6J mice. After oral administration of I3A, its radioprotective ability was assessed through the observation of survival rates, clinical scores, and pathological analysis. Intestinal stem cell survival and changes in the intestinal barrier were observed through immunofluorescence and immunohistochemistry. Subsequently, the radioprotective mechanisms of I3A was investigated through 16S rRNA and transcriptome sequencing, respectively. Finally, human colon cancer cells and organoids were cultured to assess the influence of I3A on tumor radiotherapy. I3A exhibited the most potent radioprotective effect on intestinal organoids. Oral administration of I3A treatment significantly increased the survival rate in irradiated mice, improved clinical and histological scores, mitigated mucosal damage, enhanced the proliferation and differentiation of Lgr5+ intestinal stem cells, and maintained intestinal barrier integrity. Furthermore, I3A enhanced the abundance of probiotics, and activated the AhR/IL-10/Wnt signaling pathway to promote intestinal epithelial proliferation. As a crucial tryptophan metabolite, I3A promotes intestinal epithelial cell proliferation through the AhR/IL-10/Wnt signaling pathway and upregulates the abundance of probiotics to treat RIE. Microbiota-derived I3A demonstrates potential clinical application value for the treatment of RIE.

Probiotic Consortia Protect the Intestine Against Radiation Injury by Improving Intestinal Epithelial Homeostasis

PurposeRadiation-induced intestinal injuries (RIII) commonly occur during abdomin-pelvic cancer radiotherapy; however, no effective prophylactic or therapeutic agents are available to manage RIII currently. This study aimed to clarify the potential of probiotic consortium supplementation in alleviating RIII. Materials and MethodsMale C57BL/6J mice were orally administered a probiotic mixture comprising Bifidobacterium longum BL21, Lactobacillus paracasei LC86, and Lactobacillus plantarum Lp90 for 30 days before exposure to 13 Gy of whole abdominal irradiation (WAI). The survival rates, clinical scores, and histological changes in the intestines of mice were assessed. The impacts of probiotic consortium treatment on intestinal stem cells (ISCs) proliferation, differentiation, and epithelial barrier function, oxidative stress, and inflammatory cytokines were evaluated. A comprehensive examination of the gut microbiota composition was conducted through 16S rRNA sequencing, while changes in metabolites were identified using liquid chromatography-mass spectrometry. ResultsThe probiotic consortium alleviated RIII, as reflected by increased survival rates, improved clinical scores, and mitigated mucosal injury. The probiotic consortium treatment exhibited enhanced therapeutic effects at the histological level when compared to individual probiotic strains, although there was no corresponding improvement in survival rates and colon length. Moreover, probiotic consortium stimulated ISCs proliferation and differentiation, enhanced the integrity of the intestinal epithelial barrier, and regulated redox imbalance and inflammatory responses in irradiated mice. Notably, the treatment induced a restructuring of gut microbiota composition, particularly enriching short-chain fatty acid-producing bacteria. Metabolomic analysis revealed distinctive metabolic changes associated with probiotic consortium, including elevated levels of anti-inflammatory and anti-radiation metabolites. ConclusionsThe probiotic consortium attenuated RIII by modulating the gut microbiota and metabolites, improving inflammatory symptoms, and regulating oxidative stress. These findings provide new insights into the maintenance of intestinal health with the probiotic consortium supplementation and will facilitate the development of probiotic-based therapeutic strategies for RIII in clinical practice.

Nocardia rubra cell-wall skeleton mitigates whole abdominal irradiation-induced intestinal injury via regulating macrophage function.

Ionizing radiation (IR)-induced intestinal injury is a major side effect and dose-limiting toxicity in patients receiving radiotherapy. There is an urgent need to identify an effective and safe radioprotectant to reduce radiation-induced intestinal injury. Immunoregulation is considered an effective strategy against IR-induced injury. The purpose of this article was to investigate the protective effect of Nocardia rubra cell wall skeleton (Nr-CWS), an immunomodulator, on radiation-induced intestinal damage and to explore its potential mechanism. C57BL/6J male mice exposed to 12Gy whole abdominal irradiation (WAI) were examined for survival rate, morphology and function of the intestine and spleen, as well as the gut microbiota, to comprehensively evaluate the therapeutic effects of Nr-CWS on radiation-induced intestinal and splenetic injury. To further elucidate the underlying mechanisms of Nr-CWS-mediated intestinal protection, macrophages were depleted by clodronate liposomes to determine whether Nr-CWS-induced radioprotection is macrophage dependent, and the function of peritoneal macrophages stimulated by Nr-CWS was detected in vitro. Our data showed that Nr-CWS promoted the recovery of intestinal barrier function, enhanced leucine-rich repeat-containing G protein-coupled receptor 5+ intestinal stem cell survival and the regeneration of intestinal epithelial cells, maintained intestinal flora homeostasis, protected spleen morphology and function, and improved the outcome of mice exposed to 12Gy WAI. Mechanistic studies indicated that Nr-CWS recruited macrophages to reduce WAI-induced intestinal damage. Moreover, macrophage depletion by clodronate liposomes blocked Nr-CWS-induced radioprotection. In vitro, we found that Nr-CWS activated the nuclear factor kappa-B signaling pathway and promoted the phagocytosis and migration ability of peritoneal macrophages. Our study suggests the therapeutic effect of Nr-CWS on radiation-induced intestinal injury, and provides possible therapeutic strategy and potential preventive and therapeutic drugs to alleviate it.

Probiotic Consortia and their Metabolites Protect Intestine Against Radiation Injury by Improving Intestinal Epithelial Homeostasis

The intestine is a highly radiosensitive tissue that is susceptible to structural and functional damage due to systemic as well as localized radiation exposure. Unfortunately, no therapeutic agents are available at present to manage radiation-induced intestinal injuries (RIII). Probiotics, especially Lactobacillus or Bifidobacterium, are orally taken as food supplements or microbial drugs by patients with gastrointestinal disorders due to their safety, efficacy, and power to restore the gut microenvironment. Our results demonstrate that probiotic consortia and their metabolites could exert protective roles in the RIII mouse model by restoring the structure of the gut microbiota and regulating redox imbalance. Moreover, the effect of probiotic consortia is better than that of any single probiotic strain. Male C57BL/6J mice were treated with 13 Gy of whole abdominal irradiation (WAI). Probiotics were administered by gavage before (once a day for 30 days) WAI. The survival and body weight were recorded, while the severity of RIII was evaluated by HE staining, immunohistochemistry (IHC) and TUNEL assay of gut tissues. Meanwhile, stool samples were obtained 3.5 d after irradiation. Gut microbiome were measured by 16S rRNA sequencing, and metabolites were detected by LC-MS analysis. For sterile fecal filtrate (SFF), the supernatants were collected and passed through 70 and 0.2μm filters. Compared to the control, probiotic consortia (Lactobacillus plantarum, Bifidobacterium longum, Lactobacillus paracasei) treatment significantly increased survival rates by 50% (P<0.05) and improved clinical scores of mice after WAI. HE staining showed that probiotics mitigated RIII, as reflected by the dramatic attenuation of crypt-villus architecture destruction. IHC results showed that probiotic consortia treatment markedly increased the Lgr5+ cells, Paneth cells, and Ki67+ cells (P<0.001) per crypt, indicating that probiotics promoted the proliferation and differentiation of ISCs after WAI. Consistent with the H&E staining, the level of CD4/CD8 was increased by the probiotic consortia compared with that of the control group. The probiotic consortia modulated the structure of the gut microbiota and metabolites in the RIII mouse model. To further investigate the impact of metabolites on RIII, crude probiotic fermentation metabolites were administered to the RIII mouse model. Specifically, mice fed the mixed-metabolite daily for 7 days before IR had significantly more Lgr5+ and Ki67+cells in the SI crypt than mice of control. Moreover, treatment with mixed metabolites resulted in insignificant changes in SOD, MDA, GSH and T-AOC activity compared to the control group in intestinal tissues. In the present study, we demonstrate that probiotic consortia and their metabolites treatment attenuate RIII by modulating the structure and composition of the gut microbiota and regulating redox imbalance.

7-Hydroxy-6-Methoxycoumarin 8-Glucoside (Fraxin) Confers Protection against Ionizing Radiation-Induced Intestinal Epithelial Cell Death Both In Vitro and In Vivo

The small intestine is highly sensitive to ionizing radiation. Radiation-induced intestinal injury (RIII) limits the therapeutic effect of tumor radiotherapy. However, there are currently few effective treatments available for the prevention or mitigation of RIII. Fraxin, structurally a derivative of a coumarin glucoside extracted from the herbal Cortex Qinpi, has the advantages of low toxicity and relatively low cost. Some studies have proven that Fraxin has anti-inflammatory and antibacterial effects. Our results show that Fraxin can not only promote the regeneration of intestinal stem cells and repair the intestinal structure caused by irradiation but also regulate the composition of gut microbiota and then play an immunomodulatory role through IL-22 signaling pathways, resulting in radioprotective effects. Human intestinal epithelial cells (HIECs) and intestinal organs were used as experimental models in vitro. The experimental group was irradiated with 6 Gy, detected by a cell counting kit, cell cloning, apoptosis, γ-H2AX and 8-OHdG IF. Male C57BL/6 mice aged 6-8 weeks were given a single dose of whole abdominal irradiation (WAI) at 13 Gy, detected by HE staining, IHC, IF and TUNEL methods, and survival and body weight changes were recorded, fecal samples and small intestinal tissue samples were collected 6 hours and 3 days after irradiation, and the gut microbiota was detected by 16S rRNA sequencing. Whole small intestinal tissue was analyzed by genomic transcript spectrum and RNA sequencing. Compared with vehicle treatment, Fraxin administration significantly improved the quality of life after WAI and maintained the body weight of mice. In addition, the crypt-villus architecture of the intestinal tracts in mice treated with Fraxin was well preserved, and the number of goblet cells, Lgr5+ intestinal stem cells (ISCs) and their daughter cells, Ki67+ proliferating cells increased significantly, reducing the structural damage caused by radiation. Meanwhile, Fraxin improved the expression of tight junction proteins such as E-cadherin and Claudin-3 after WAI, strikingly reduced the levels of FITC-dextran in serum, maintained the integrity of the intestinal barrier. In addition, we have confirmed that Fraxin can increase the cell viability of HIECs, reduce the 8OHdG fluorescence intensity induced by IR, and reduce γ H2AX lesions and apoptosis. Fraxin administration recovered the disorder of the structure of gut microbiota after irradiation and promoted the expression of probiotics, and KEGG pathway analysis suggested that it was related to immunity. Transcriptional sequencing showed that the IL-22 signaling pathway was significantly activated in the Fraxin treatment group, suggesting that Fraxin may have a protective effect on intestinal radiation through IL-22. In conclusion, Fraxin treatment attenuate RIII by modulating the composition of the gut microbiota and activate the IL-22 signaling pathway to reduce RIII.

Postoperative Radiotherapy to Abdominal and Pelvic Lymphatic Drainage Area for Stage III Epithelial Ovarian Cancer: A Sharp Tool to Prolong Disease-Free Survival Time

For patients with stage III epithelial ovarian cancer, there are limited studies on the effects of postoperative adjuvant radiotherapy (RT) after standard cytoreductive surgery (CRS) and full treatment of first-line adjuvant chemotherapy (CT). The aims of our study were to assess the therapeutic efficacy and toxicity of our special postoperative radiotherapy to abdominal and pelvic lymphatic drainage area for stage III epithelial ovarian cancer patients. We retrospectively collected patients with stage III epithelial ovarian cancer after CRS and full-course adjuvant chemotherapy. The CT+RT group patients were treated with intensity modulated radiotherapy (IMRT) to abdominal and pelvic lymphatic drainage area (which has been shown to be an alternative to whole abdominal radiotherapy (WART) both on the basis of clinical result and dosimetric verification from our prior study). The CT group data was obtained from the PUMCH's electronic medical record analytical database between 2010 and 2020. A propensity score matching analysis was performed 1:2 between CT+RT group and CT group. A total of 132 patients with median follow-up of 73.9 months (9.1-137.7 months) were included (44 and 88 for the CT+RT and CT groups, retrospectively). The baseline characteristics of age, histology, level of CA12-5, surgical staging, residual tumor, courses of adjuvant CT, and courses to reduce CA12-5 to normal were all balanced. The median disease-free survival (DFS) time, 5-year overall survival (OS), and local recurrence free survival (LRFS) of CT+RT group and CT group were 100.0 months versus 25.9 months (p = 0.020), 69.2% versus 49.9% (p = 0.002), 85.9% versus 50.5% (p = 0.020), respectively. Distant metastasis was still the primary reason (57.6%), and local failure rate was 42.3%, the local recurrence rate was significantly lower in CT+RT group, compared with CT group (13.6% versus 45.5%, p = 0.016). In terms of toxicity, CT+RT group mainly presented with acute hematological toxicities, with no statistically significant difference with CT group when compared with grade III intestinal adverse effects (3/44 versus 6/88, p = 0.480). This report demonstrates that long-term disease-free survival could be achieved in stage III epithelial ovarian cancer patients treated with IMRT preventive radiation to abdominal and pelvic lymphatic area. Compared with CT group, DFS and OS were significantly prolonged and adverse effects were acceptable.

Kidney Disease in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

Kidney injury is a known late and potentially devastating complication of abdominal radiation therapy (RT) in pediatric patients. A comprehensive Pediatric Normal Tissue Effects in the Clinic review by the Genitourinary (GU) Task Force aimed to describe RT dose-volume relationships for GU dysfunction, including kidney, bladder, and hypertension, for pediatric malignancies. The effect of chemotherapy was also considered. We conducted a comprehensive PubMed search of peer-reviewed manuscripts published from 1990 to 2017 for investigations on RT-associated GU toxicities in children treated for cancer. We retrieved 3271 articles with 100 fulfilling criteria for full review, 24 with RT dose data and 13 adequate for modeling. Endpoints were heterogenous and grouped according to National Kidney Foundation: grade ≥1, grade ≥2, and grade ≥3. We modeled whole kidney exposure from total body irradiation (TBI) for hematopoietic stem cell transplant and whole abdominal irradiation (WAI) for patients with Wilms tumor. Partial kidney tolerance was modeled from a single publication from 2021 after the comprehensive review revealed no usable partial kidney data. Inadequate data existed for analysis of bladder RT-associated toxicities. The 13 reports with long-term GU outcomes suitable for modeling included 4 on WAI for Wilms tumor, 8 on TBI, and 1 for partial renal RT exposure. These reports evaluated a total of 1191 pediatric patients, including: WAI 86, TBI 666, and 439 partial kidney. The age range at the time of RT was 1 month to 18 years with medians of 2 to 11 years in the various reports. In our whole kidney analysis we were unable to include chemotherapy because of the heterogeneity of regimens and paucity of data. Age-specific toxicity data were also unavailable. Wilms studies occurred from 1968 to 2011 with mean follow-ups 8 to 15 years. TBI studies occurred from 1969 to 2004 with mean follow-ups of 4 months to 16 years. We modeled risk of dysfunction by RT dose and grade of toxicity. Normal tissue complication rates ≥5%, expressed as equivalent doses, 2 Gy/fx for whole kidney exposures occurred at 8.5, 10.2, and 14.5 Gy for National Kidney Foundation grades ≥1, ≥2, and ≥3, respectively. Conventional Wilms WAI of 10.5 Gy in 6 fx had risks of ≥grade 2 toxicity 4% and ≥grade 3 toxicity 1%. For fractionated 12 Gy TBI, those risks were 8% and <3%, respectively. Data did not support whole kidney modeling with chemotherapy. Partial kidney modeling from 439 survivors who received RT (median age, 7.3 years) demonstrated 5 or 10 Gy to 100% kidney gave a <5% risk of grades 3 to 5 toxicity with 1500 mg/m2 carboplatin or no chemo. With 480 mg/m2 cisplatin, a 3% risk of ≥grade 3 toxicity occurred without RT and a 5% risk when 26% kidney received ≥10 Gy. With 63 g/m2 of ifosfamide, a 5% risk of ≥grade 3 toxicity occurred with no RT, and a 10% toxicity risk occurred when 42% kidney received ≥10 Gy. In patients with Wilms tumor, the risk of toxicity from 10.5 Gy of WAI is low. For 12 Gy fractionated TBI with various mixtures of chemotherapy, the risk of severe toxicity is low, but low-grade toxicity is not uncommon. Partial kidney data are limited and toxicity is associated heavily with the use of nephrotoxic chemotherapeutic agents. Our efforts demonstrate the need for improved data gathering, systematic follow-up, and reporting in future clinical studies. Current radiation dose used for Wilms tumor and TBI appear to be safe; however, efforts in effective kidney-sparing TBI and WAI regimens may reduce the risks of renal injury without compromising cure.

Oral konjac glucomannan for prevention of ionizing radiation-induced injury by regulating gut microbiota and increasing short chain fatty acids

Ionizing radiation-induced injury commonly happens in radiotherapy, leading to damages of the hematopoietic and gastrointestinal systems. Radioprotective medications are mainly applied in hospitals, although only injections are available and their gut protection is limited. Here, oral konjac glucomannan (KGM), a natural macromolecule and soluble dietary fiber, was used against ionizing radiation-induced injury. The mice were fed with KGM (0.4 g/kg) for 3 days or injected with a clinical medication amifostine before 6.5 Gy γ-ray whole body irradiation (WBI) or 13 Gy whole abdominal irradiation (WAI). In the WBI experiments, KGM improved blood cell recovery and bone marrow cell proliferation in the femur and spleen, though its effect was weaker than or similar to that of amifostine. In the WBI experiments, the gut protection of KGM was similar to or a little better than that of amifostine, involving regenerated crypts numbers, villus length, and gut permeability. Moreover, KGM remarkably enhanced the survival rates of WBI and WAI mice, consistent with amifostine. KGM, as a prebiotic, enhanced gut microbiota abundance, probiotic numbers, and short chain fatty acid production, maintaining gut homeostasis. Moreover, KGM inhibited the apoptosis of irradiated human intestinal epithelial cells. KGM is a promising natural macromolecule against ionizing radiation-induced injury.

High-fat diet alters the radiation tolerance of female mice and the modulatory effect of melatonin.

High-fat diet (HFD) increases the risk of developing malignant tumors. Ionizing radiation (IR) is used as an adjuvant treatment in oncology. In this study, we investigated the effects of an 8-week 35% fat HFD on the tolerance to IR and the modulatory effect of melatonin (MLT). The results of lethal dose irradiation survival experiments revealed that the 8-week HFD altered the radiation tolerance of female mice and increased their radiosensitivity, whereas it had no comparable effects on males. Pre-treatment with MLT was, however, found to attenuate the radiation-induced hematopoietic damage in mice, promote intestinal structural repair after whole abdominal irradiation (WAI), and enhance the regeneration of Lgr5+ intestinal stem cells. 16S rRNA high-throughput sequencing and untargeted metabolome analyses revealed that HFD consumption and WAI sex-specifically altered the composition of intestinal microbiota and fecal metabolites and that MLT supplementation differentially modulated the composition of the intestinal microflora in mice. However, in both males and females, different bacteria were associated with the modulation of the metabolite 5-methoxytryptamine. Collectively, the findings indicate that MLT ameliorates the radiation-induced damage and sex-specifically shapes the composition of the gut microbiota and metabolites, protecting mice from the adverse side effects associated with HFD and IR.

Sex Differences of Radiation Damage in High-Fat-Diet-Fed Mice and the Regulatory Effect of Melatonin.

The consumption of a high-fat diet (HFD) and exposure to ionizing radiation (IR) are closely associated with many diseases. To evaluate the interaction between HFDs and IR-induced injury, we gave mice whole abdominal irradiation (WAI) to examine the extent of intestinal injury under different dietary conditions. Melatonin (MLT) is a free radical scavenger that effectively prevents hematopoietic, immune, and gastrointestinal damage induced by IR. However, its effects on WAI-induced intestinal injury in HFD-fed mice remain unclear. We demonstrated that MLT can promote intestinal structural repair following WAI and enhance the regeneration capacity of Lgr5+ intestinal stem cells. In addition, we investigated the effects of radiation damage on sexual dimorphism in HFD-fed mice. The results showed that the degree of IR-induced intestinal injury was more severe in the HFD-fed female mice. MLT preserved the intestinal microbiota composition of HFD-fed mice and increased the abundance of Bacteroides and Proteobacteria in male and female mice, respectively. In conclusion, MLT may reduce the negative effects of HFD and IR, thereby providing assistance in preserving the structure and function of the intestine.

Microbiota-Derived I3A Accelerates Intestinal Stem-Cell-Mediated Epithelial Development after Ionizing Radiation

<h3>Purpose/Objective(s)</h3> The intestine is a highly radiosensitive tissue that is susceptible to structural and functional damage due to systemic as well as localized radiation exposure. Unfortunately, no effective prophylactic or therapeutic agents are available at present to manage radiation-induced intestinal injuries (RIII). Gut microbiome play pivotal roles in intestinal homeostasis. Several studies have demonstrated the potential of gut microbiome and metabolites as a therapeutic for RIII. Our results demonstrate that microbiota-derived Indole-3-carboxaldehyde (I3A) plays a pivotal role in promoting ISC-mediated epithelial development. <h3>Materials/Methods</h3> Male C57BL/6J mice were treated with 13Gy of Whole abdominal irradiation (WAI). Probiotics or I3A were gavage before (once a day for 30 days) WAI. The survival and body weight were recorded, while the severity of RIII was evaluated by HE staining, Immunohistochemistry (IHC) and TUNEL assay of gut tissues for each irradiated group. Meanwhile, stool samples were obtained 6h and 3.5d after irradiation. Gut microbiome were measured by 16S rRNA sequencing, and metabolites were detected by LC-MS analysis. <h3>Results</h3> Compared to the control, probiotics (Lactobacillus plantarum, Bifidobacterium longum, Lactobacillus paracasei) treatment significantly increased survival rates by 50% (P<0.05) and improved clinical scores of mice after WAI. HE staining of jejunum tissues showed that probiotics mitigated RIII, as reflected by the dramatic attenuation of crypt-villi architecture destruction. IHC results showed that probiotics treatment remarkably increased the Lgr5⁺ cells, Paneth cells, and Ki67+cells (P<0.001) per crypt, indicating that probiotics promoted proliferation and differentiation of ISC after WAI. The most highly enriched metabolites from the feces of probiotics treatment mice in the tryptophan metabolic pathway, with a threefold change seen in level of I3A. Specifically, I3A -treated groups showed survival rates of ∼20%%, with the protection persisting for >200 days after radiation. In addition, mice fed the I3A daily for 3 days before IR had significantly more Lgr5+, Paneth cells, Goblet cells, and Ki67⁺cells in the SI crypt than mice of control. Moreover, treatment with I3A resulted in enhanced numbers of Lgr5⁺ cells and Paneth cells and Wnt3 expression in SI organoids. <h3>Conclusion</h3> Collectively, our findings suggested that microbiota-derived I3A protects against RIII by promote the proliferation and differentiation of Lgr5+ intestinal stem cells via Wnt signaling pathway.

Abstract 811: Pharmacologic ascorbate opens a therapeutic window for ATM inhibition and radiotherapy in colorectal cancer

Abstract Purpose/Objective(s): The ATM protein is key to DNA double strand break (DSB) repair and ATM inhibitors are potent radiosensitizers. Clinical translation of these agents in combination with radiotherapy (RT) has been limited due to concerns for increased normal tissue toxicity. Pharmacologic Ascorbate (P-AscH-) radiosensitizes cancer cells via generation of a H2O2 flux while acting as a radioprotector in normal tissue via free radicle scavenging. We hypothesized that P-AscH- could open a therapeutic window for the combination of RT and ATM inhibition in colorectal cancer (CRC). Materials/Methods: Multiple human and murine CRC cell lines were used in vitro. Clonogenic survival was assessed after combinations of RT +/- P-AscH and DNA Repair Inhibitors (DRIs). Catalase expression was induced using HCT116 cells expressing a doxycycline-inducible catalase transgene. DSBs were quantified using neutral comet assays. Cell cycle distribution were assessed using flow cytometry. ATM localization/activation were assessed using IF. Normal tissue toxicity in vivo was assessed using IHC following whole-abdominal RT. Survival and tumor growth delay was assessed following 5Gyx3 +/- drug treatment to unilateral flank tumors in syngeneic/xenograft models. Results: DRIs were potent radiosensitizers in most CRC cell lines and the addition of P-AscH- further reduced clonogenic survival. In contrast, P-AscH- did not radiosensitize HUVEC or FHs-74int normal cell lines. P-AscH- significantly increased the number of DSBs in tumors after RT in vitro. P-AscH- simultaneously decreased nuclear localization and activation of pATM after RT and perturbed G2+M phase progression. In vivo, the addition of P-AscH- to RT + KU60019 significantly increased survival delayed tumor growth in syngeneic/xenograft models while ameliorating increased normal bowel toxicity as measured by jejunal crypt density, acute weight loss, rectal injury, and markers of oxidative stress following whole-abdominal RT. The effects of P-AscH were reversed by inducing the overexpression of catalase. Conclusion: P-AscH- improves both aspects of the therapeutic window of RT+ATM inhibition in CRC by simultaneously enhancing tumor efficacy while decreasing RT-mediated bowel toxicity. The effects of P-AscH- on clonogenic survival, initial and persistent DSBs, G2+M phase perturbations, ATM activation/localization, and in vivo survival and tumor growth delay were dependent on H202 flux. Normal tissue protection appears to be related to decreased oxidative stress. Citation Format: Cameron M. Callaghan, Ibrahim M. Abukhiran, Richard V. Van Rheeden, Amanda L. Kalen, Samuel N. Rodman, Michael S. Petronek, Kranti A. Mapuskar, Sarah L. Mott, Mitchell C. Coleman, Prabhat C. Goswami, John M. Buatti, Bryan G. Allen, Douglas R. Spitz, Joseph M. Caster. Pharmacologic ascorbate opens a therapeutic window for ATM inhibition and radiotherapy in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 811.

Abdominopelvic Lymphatic Drainage Area Irradiation for Consolidative Radiotherapy of Advanced Ovarian Carcinoma: Analysis of Clinical Application Efficacy and Dosimetric Verification.

BackgroundThe aim of the study was to evaluate the efficacy of abdominopelvic lymphatic drainage area irradiation (APLN), instead of whole abdominal radiotherapy (WART), in the consolidative radiotherapy of advanced ovarian carcinoma patients.MethodsWe conducted a retrospective analysis collecting 99 patients with locally advanced ovarian cancer treated by APLN with 45 - 50 Gy/25- 28 fractions/5-7#, instead of WART. We evaluated the clinical outcome of APLN. Five patients were selected for dosimetric verifications verses WART (30 Gy/20 fractions). The normal tissue complication probability (NTCP) was calculated for the two treatment methods.ResultsThe mean follow-up time was 64.10 months (5.5 - 113.2 months), after APLN consolidative radiotherapy, 1-, 3-, and 5-year overall survival (OS) was 87.9%, 81.3%, and 61.5%, median disease-free survival (DFS) was 40.8 months, 5-year local recurrence free survival (LRFS) was 75.9%, and 5-year distant metastasis free survival (DMFS) was 49.2%. One patient died due to intestinal perforation. Local recurrence in the area between WART and APLN was rare (3/99 patients). The number of surgical procedures < 2 was an independent risk factor for LRFS (P = 0.023). Dosimetric comparison showed that comparing with WART, APLN significantly reduced the organ at risk (OAR) dose: 25.37 ± 3.63 Gy (25%) for liver, 8.77 ± 5.03 Gy (25%) for kidney, 8.14 ± 1.51 Gy (25%) for small intestine, etc. NTCP was reduced by 0.04-1.04% for liver, kidney, and small intestine.ConclusionFor consolidative radiotherapy in locally advanced ovarian cancer, APLN (intensity-modulated radiotherapy 45 - 50 Gy/25 - 28 fractions) could be an alternative to WART, resulting in excellent LRFS and DFS, with acceptable toxicities, comparing with previous literature reports. Dosimetric analysis also showed the benefits of APLN in NTCP.

Sitagliptin Alleviates Radiation-Induced Intestinal Injury by Activating NRF2-Antioxidant Axis, Mitigating NLRP3 Inf--lammasome Activation, and Reversing Gut Microbiota Disorder.

Radiation-induced intestinal injury is a common and critical complication of radiotherapy for pelvic or abdominal tumors, with limited therapeutic strategies and effectiveness. Sitagliptin, a dipeptidyl peptidase IV (DPP4) inhibitor, has previously been reported to alleviate total body irradiation- (TBI-) induced damage of hematopoietic system in mice, but its effect on radiation-induced intestinal injury remains unclear. In this study, we confirmed that Sitagliptin could not only protect mice from death and weight loss caused by whole abdominal irradiation (WAI) but also improve the morphological structure of intestine and the regeneration ability of enterocytes. In addition, Sitagliptin significantly inhibited the production of radiation-induced proinflammatory cytokines and reduced the number of apoptotic intestinal epithelial cells and γ-H2AX expression. In vitro, we demonstrated that Sitagliptin protected HIEC-6 cells from ionizing radiation, resulting in increased cell viability and reduced DNA damage. Mechanistically, the radiation protection of Sitagliptin might be related to the upregulation of NRF2 level and the decrease of NLRP3 inflammasome activity. Importantly, Sitagliptin significantly restored radiation-induced changes in bacterial composition. In conclusion, our results suggested that Sitagliptin could reduce WAI-induced intestinal injury in mice, which may provide novel therapeutic strategy for radiation-induced intestinal injury.

Preventive effect of sanguinarine on intestinal injury in mice exposed to whole abdominal irradiation

Intestinal injury is one of the major side effects that are induced by medical radiation exposure, and has limited effective therapies. In this study, we investigated the beneficial effects of sanguinarine (SAN) on intestinal injury induced by ionizing radiation (IR) both in vitro and in vivo. Mice were exposed to whole abdominal irradiation (WAI) to mimic clinical scenarios. SAN was injected intraperitoneally to mitigate IR-induced injury. Histological examination was performed to assess the tissue injuries of the spleen and small intestine. A small intestinal epithelial cell line-6 (IEC-6) was analyzed for its viability and apoptosis in vitro under different treatments. Inflammation-related pathways and serum inflammatory cytokines were detected via Western blot analysis and ELISA, respectively. High-throughput sequencing was used to characterize the gut microbiota profile. High-performance liquid chromatography was performed to assess short-chain fatty acid contents in the colon. In vitro, SAN pretreatment protected cell viability and reduced apoptosis in IEC-6 cells. In vivo, SAN pretreatment protected immune organs, alleviated intestinal injury, and promoted intestinal recovery. SAN also reduced the levels of inflammatory cytokines, suppressed high mobility group box 1 (HMGB1)/ Toll-like receptor 4 (TLR4) pathway activation, and modulated gut microbiota composition. Our findings demonstrate that the beneficial properties of SAN alleviated intestinal radiation injury. Thus, SAN represents a therapeutic option for protecting against IR-induced intestinal injury in preclinical settings.

De-Escalated Radiotherapy for Advanced Stage Wilms Tumor: A Single-Center Experience

<h3>Purpose/Objective(s)</h3> Survival rates have dramatically improved in Wilms tumor (WT) with multimodal treatment. Herein, we aimed to compare the efficacy of 9 Gy to 10.8 Gy flank RT or whole abdominal irradiation (WAI) in patients with WT treated in a single tertiary treatment center. <h3>Materials/Methods</h3> This study includes 42 patients with a unilateral or bilateral WT with a local stage III disease who received a low-dose (10.8 Gy) or lower-dose (9 Gy) flank RT or WAI between 1998 and 2018. Patients had undergone either upfront surgery followed by adjuvant chemotherapy (CXT) or neoadjuvant CXT followed by surgery. Patients with lung metastasis without a complete response to CXT also received whole lung irradiation (WLI) of 9-12 Gy. <h3>Results</h3> The disease was staged as III in 22, IV in 12, and V in 9 patients, respectively. After a median follow-up of 75 months, the 2- and 5-year overall survival, locoregional relapse-free survival, and distant metastasis-free survival rate was 92% and 79%, 87% and 76%, and 75% and 69%, respectively. None of these survival rates were different among 9 Gy and 10.8 Gy doses. Among patients receiving WLI, the lung relapse rate was also similar between < 12 Gy and 12 Gy of irradiation. Late toxicity was observed in four (10%) patients as scoliosis, cardiac dysfunction, renal injury and hypertension, and short stature. <h3>Conclusion</h3> De-escalated RT of 9 Gy to the flank or abdomen does not compromise oncologic outcomes in patients with a local stage III WT.

Utility of adjuvant whole abdominal radiation therapy in ovarian clear cell cancer (OCCC): a pragmatic cohort study of women with classic immuno-phenotypic signature

BackgroundTo evaluate the initial experience and clinical utility of first-line adjuvant intensity-modulated whole abdominal radiation therapy (WART) in women with ovarian clear cell cancer (OCCC) referred to an academic center.MethodsProgression-free and overall survival was analyzed in a pragmatic observational cohort study of histologically pure OCCC patients over-expressing HNF-1ß treated between 2013 and end-December 2018. An in-house intensity-modulated WART program was developed from a published pre-clinical model. Radiation dose-volume data was curated to American Association of Physics in Medicine (AAPM) Task Group 263 recommendations. A dedicated database prospectively recorded presenting characteristics and outcomes in a standardized fashion.ResultsFive women with FIGO (2018) stage IA to IIIA2 OCCC were treated with first-line WART. Median age was 58 years (range 47–68 years). At diagnosis CA-125 was elevated in 4 cases (median 56 kU/L: range 18.4–370 kU/L) before primary de-bulking surgery. Severe premorbid endometriosis was documented in 3 patients. At a median follow-up of 77 months (range 16–83 mo.), all patients remain alive and progression-free on clinical, biochemical (CA-125), and 18Fluoro-deoxyglucose (FDG) PET/CT re-evaluation. Late radiation toxicity was significant (G3) in 1 case who required a limited bowel resection and chronic nutritional support at 9 months post-WART; 2 further patients had asymptomatic (G2) osteoporotic fragility fractures of axial skeleton at 12 months post-radiation treated with anti-resorptive agents (denosumab).ConclusionsThe clinical utility of intensity-modulated WART in OCCC over-expressing HNF-1β was suggested in this small observational cohort study. The hypothesis that HNF-1β is a portent of platinum-resistance and an important predictive biomarker in OCCC needs further confirmation. Curating multi-institutional cohort studies utilizing WART by means of “Big Data” may improve OCCC care standards in the future.

Radiotherapy in women with epithelial ovarian cancer: historical role, current advances, and indications.

Epithelial ovarian cancer (OC) is known to be a neoplasm responsive to radiotherapy (RT). Nevertheless, the role of RT in the management of this disease represent a topic of controversy, and the indications for its use are not fully established. Initial studies suggested that the addition of RT in the form of intraperitoneal (IP) radioisotopes was useful. Indications for this treatment were peritoneal cytology with tumor cells, peritoneal implants, and capsule rupture. The instillation of radioisotopes was contraindicated when macroscopic residual disease was present. Pelvic RT was used after surgery in patients with an absence of gross residual disease. Early studies established the inadequacy of this technique and the need for treating the whole abdomen. Whole abdominal irradiation (WAI) was a therapeutic tool used in the prechemotherapy era to eradicate large amounts of microscopic peritoneal disease. Ideal candidates for WAI were stage I patients with grade 2 or 3 tumors; stage II patients with grade 1 or 2 tumors and residual disease, and stage III, grade 1 patients with <2 cm residual disease. The disadvantages of WAI were the dose-limiting toxicities, which were predominantly acute hematologic and late gastrointestinal. The era of aggressive debulking and platinum agents made WAI fall out of favor as a treatment of OC. Selective approaches with highly conformal radiotherapy (CRT) have been used in case of limited recurrent or unresectable disease with the potential for long-term disease control. Currently, the role of RT in OC applies for patients with recurrent oligometastatic or oligoprogressive disease and in the palliative setting for symptom control. We performed a nonsystematic review and included data from both retrospective and prospective studies focusing on the use of RT for OC and its biological rationale. Furthermore, ongoing trials on this issue are reported.

At What Dose Can Total Body and Whole Abdominal Irradiation Cause Lethal Intestinal Injury Among C57BL/6J Mice?

Purpose and Methods:To investigate the doses of total body (TBI) and whole abdominal irradiation (WAI) induced lethal intestinal injury, healthy C57BL/6 J mice were divided randomly into 7 groups: control group; 6, 7, and 8 Gy TBI groups; and 5, 10, and 15 Gy WAI groups. The survival length, general conditions, body weight, daily food and water intake of the mice and the histopathological changes of small intestine were observed.Results:Lethal injury among C57BL/6 J mice was caused by ≥6 Gy TBI and 15 Gy WAI. Their body weight and food intake decreased, the structure of their small intestinal villi was destroyed, and the number of surviving crypts per circumference of the jejunum decreased in ≥6 Gy TBI groups and 15 Gy WAI group. The mice in the 10 Gy WAI group significantly lost weight within 5 days but recovered slowly thereafter. They also had poor appetite and reversibly damaged intestinal mucosa.Conclusions:Nonlethal intestinal injury could be induced by 10 Gy WAI, whereas lethal intestinal injury could be triggered by ≥6 Gy TBI and >15 Gy WAI in mice. Our results provided a basis for establishing radiation-induced intestinal injury models with C57BL/6 J mice.

Adjuvant intensity modulated whole-abdominal radiation therapy for high-risk patients with ovarian cancer FIGO stage III: final results of a prospective phase 2 study

BackgroundTo assess late toxicity, quality of life and oncological outcome after consolidative whole abdominal radiotherapy (WART) following cytoreductive surgery and carboplatin/paclitaxel chemotherapy in high risk patients with advanced ovarian cancer FIGO stage III using IMRT (Intensity modulated radiation therapy).MethodsThe OVAR-IMRT-02 study is a multi-center single-arm phase-II-trial. Twenty patients with optimally debulked ovarian cancer stage FIGO III with complete remission after chemotherapy were treated with intensity modulated WART. A total dose of 30 Gy in 20 fractions was applied to the entire peritoneal cavity. Primary endpoint was treatment tolerability; secondary objectives were acute and chronic toxicities, quality of life, rates of therapy disruption/abortion, progression-free survival (PFS) and overall survival (OS).ResultsAll patients completed treatment and 10/20 patients (50%) reached the final study follow-up of 36 months. Late side effects consisted of °1-°2 lower limb edema (44.5%), with one patient (5.6%) showing °3 edema. Three patients (16.7%) showed elevated gamma-Glutamyltransferase. There were no severe late side effects regarding renal or hepatic function or any gastrointestinal toxicity greater than °2. During WART, mean global health status decreased by 18.1 points (95%-CI: 7.1–29.0), but completely normalized after 6 months. The same trend was observed for the function scale scores. Kaplan-Meier-estimated 1-, 2- and 3-year PFS was 74, 51 and 40%, respectively. 1-, 2- and 3-year OS was 89, 83 and 83%, respectively.ConclusionsIntensity modulated WART after aggressive surgery and carboplatin/paclitaxel chemotherapy is associated with an acceptable risk of acute and late toxicity and minor impact on long-term quality of life. Together with the promising results for PFS and OS, intensity modulated WART could offer a new therapeutic option for consolidation treatment of patients with advanced ovarian cancer.Trial registrationThe study is registered with ClinicalTrials.gov (NCT01180504). Registered 12 August 2010 – retrospectively registered.