Serum Monitoring and Phenotype Identification of Stage I Non-Small Cell Lung Cancer Patients.

A stage I non-small cell lung cancer (NSCLC) serum profiling platform is presented which is highly efficient and accurate. Test sensitivity (0.95) for stage I NSCLC is the highest reported so far. Test metrics are reported for discriminating stage I adenocarcinoma vs squamous cell carcinoma subtypes. Blinded analysis identified 23 out of 24 stage I NSCLC and control serum samples. Group-discriminating mass peaks were targeted for tandem mass spectrometry peptide/protein identification, and yielded a lung cancer phenotype. Bioinformatic analysis revealed a novel lymphocyte adhesion pathway involved with early-stage lung cancer.

DCLK1 is detectable in plasma of patients with Barrett's esophagus and esophageal adenocarcinoma.

BACKGROUND: Doublecortin-like kinase 1 (DCLK1), a putative tumor stem cell marker has been shown to be highly expressed in the stromal and epithelial compartments in colon and pancreatic cancer as well as Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). AIM: To prospectively investigate whether the immunohistochemical expression of DCLK1 was associated with detectable DCLK1 plasma expression in patients with existing BE and EAC. METHODS: Immunohistochemistry was performed on paraffin-embedded sections using DCLK1 antibody and scored based on staining intensity and tissue involvement. Purified human plasma samples were subjected to Western blot and ELISA analysis. RESULTS: Forty (40) patients were enrolled: 10 controls (normal endoscopy) and 30 with BE/EAC (13 nondysplastic BE [NDBE], 9 dysplastic BE [DBE] and 8 EAC). Mean epithelial DCLK1 staining was as follows: controls = 0.11, NDBE = 3.83, DBE = 6.0, EAC = 7.17. Mean stromal DCLK1 staining was as follows: NDBE = 5.83, DBE = 5.375, EAC = 10.83. DCLK1 was detected by plasma Western blot in 1 control and in all patients with BE/EAC p < 0.0005. Plasma DCLK1 was elevated by ELISA in EAC compared to other groups, p < 0.05. CONCLUSIONS: Increased expression of DCLK1 was observed in the epithelium, stroma and plasma of patients with BE/EAC. Furthermore, the presence of detectable DCLK1 in plasma of BE/EAC patients may provide a less invasive, detection tool in those patients as well as represent a novel molecular marker distinguishing between normal esophageal mucosa and BE or EAC.

Distinguishing patients with stage I lung cancer versus control individuals using serum mass profiling.

Serum mass profiling can discern physiological changes associated with specific disease states and their progression. Sera (86 total) from control individuals and patients with stage I nonsmall cell lung cancer or benign small pulmonary nodules were discriminated retrospectively by serum changes discerned by mass profiling. Control individuals were distinguished from patients with Stage I lung cancer or benign nodules with test sensitivities of 89% and 83%. Lung cancer patients versus those with benign nodules were distinguished with 80% sensitivity. This study exhibits progress toward a minimally-invasive aid in early detection of lung cancer and monitoring small pulmonary nodules for malignancy.

Mass profiling of serum to distinguish mice with pancreatic cancer induced by a transgenic Kras mutation.

Mass spectrometry (MS) has the unique ability to profile, in an easily accessible body tissue (peripheral blood/serum,) the sizes and relative amounts of a wide variety of biomolecules in a single platform setting. Using electrospray ionization (ESI)-MS, we distinguished individual serum from wild-type control mice from serum of mice containing an oncogenic Kras mutation, which leads to development of pancreatic ductal adenocarcinoma (PDAC) similar to that observed in humans. Identification of differences in significant ESI-MS sera mass peaks between Kras-activated mice and control mice was performed using t tests and a "nested leave one out" cross-validation procedure. Peak distributions in serum of control mice from mice with Kras-mutant-dependent PDAC were distinguished from those of pancreatic intraepithelial neoplasia (PanIN) lesions (p = 0.00024). In addition, Kras mutant mice with PDAC were distinguished from Kras mutant mice with PanIN alone (p = 0.0057). Test specificity, a measure of the false positives, was greater for the control vs. Kras mutated mice, and the test sensitivity, a measure of false negatives, was greater for the PDAC vs. PanIN containing mice. Receiver-operating characteristic (ROC) curve discriminatory values were 0.85 for both comparisons. These studies indicate ESI-MS serum mass profiling can detect physiological changes associated with pancreatic cancer initiation and development in a GEM (genetic engineered mouse) model that mimics pancreatic cancer development in humans. Such technology has the potential to aid in early detection of pancreatic cancer and in developing therapeutic drug interventions.

Distinguishing non-small cell lung adenocarcinoma patients from squamous cell carcinoma patients and control individuals using serum profiling.

Goals of this study were to analyze the ability of mass spectrometry serum profiling to distinguish non-small cell lung adenocarcinoma from squamous cell carcinoma patients and healthy controls. Sera were obtained from 19 adenocarcinoma patients, 24 squamous cell carcinoma patients, and 21 controls. Identifications of significant mass-to-charge ratio (m/z) peak differences between these groups were performed using t-tests. A "leave one out" cross-validation procedure yielded discriminatory lung adenocarcinoma versus squamous cell carcinoma p and ROC curve values of <.0001 and 0.92, respectively. Test sensitivity and specificity were 84% and 79%, respectively. This approach could aid in lung cancer diagnosis and sub-typing.

Serum profiling to distinguish early- and late-stage ovarian cancer patients from disease-free individuals.

Sera mass spectrometry (MS) peak differences were analyzed from 35 ovarian cancer patients and 16 disease-free individuals. "Leave one out" cross validation was used to assign "% cancer peaks" in control and ovarian cancer sera samples. Sera MS discriminated stage I/II and stage III/V ovarian cancer patients versus controls with ROC curve area values of 0.82 and 0.92. Test sensitivities for ovarian cancer stage I/II and III/V were 80% and 93% respectively. These results indicate that MS is useful for distinguishing sera from early-stage ovarian cancer patients, and has potential as a test for early detection of this disease.

Identification of the putative intestinal stem cell marker doublecortin and CaM kinase-like-1 in Barrett's esophagus and esophageal adenocarcinoma.

BACKGROUND AND AIM: In Barrett's esophagus (BE), the normal esophageal squamous epithelium is replaced with a specialized metaplastic columnar epithelium. BE is a premalignant lesion that can progress to esophageal adenocarcinoma (EAC). Currently, there are no early molecular indicators that would predict progression from BE to EAC. As the only permanent residents of the epithelium, stem cells have been implicated in this metaplastic progression. The aim of the present study was to determine the expression of doublecortin and CaM kinase-like-1 (DCAMKL-1) and other putative gastrointestinal stem cell markers in normal esophageal mucosa (NEM), BE, and EAC. METHODS: Human NEM, BE, EAC, and multitissue microarrays were analyzed for DCAMKL-1, and immunohistochemically scored based on staining intensity and tissue involvement, with epithelia and stroma scored separately. Total RNA isolated from BE and paired NEM was subjected to real-time reverse-transcription-polymerase chain reaction analysis for DCAMKL-1, leucine-rich repeat-containing G-protein-coupled receptor (LGR5), and Musashi-1 (Msi-1) mRNA expression. RESULTS: DCAMKL-1 was minimally expressed in squamous NEM, but increased in BE (with and without dysplasia) and EAC tissues. In EAC, we found increased stromal DCAMKL-1 staining compared to adjacent epithelia. Within the submucosa of dysplastic BE tissues, an increase in the endothelial cell expression of DCAMKL-1 was observed. Finally, an upregulation of DCAMKL-1, LGR5, and Msi-1 mRNA was seen in BE compared to squamous NEM. CONCLUSIONS: In the present study, we report the progressive increase of DCAMKL-1 expression in BE from dysplasia to EAC. Furthermore, there was an increase in putative stem cell markers DCAMKL-1, LGR5, and Msi-1 mRNA. Taken together, these data suggest that the regulation of resident stem cells might play an important role in the progression of BE to EAC.

Distinguishing early-stage pancreatic cancer patients from disease-free individuals using serum profiling.

This study evaluated the usefulness of electrospray mass spectrometry to distinguish sera of early-stage pancreatic cancer patients from disease-free individuals. Sera peak data were generated from 33 pancreatic cancer patients and 30 disease-free individuals. A "leave one out" cross-validation procedure discriminated stage I/II pancreatic cancer versus disease-free sera with a p value <.001 and a receiver-operator characteristic curve area value of 0.85. Predictive values for cancer stage I/II test efficiency, specificity, and sensitivity were 78%, 77%, and 79%, respectively. These studies indicate that electrospray mass spectrometry is useful for distinguishing sera of early-stage pancreatic cancer patients from disease-free individuals.

Distinguishing Alzheimer's Disease Patients and Biochemical Phenotype Analysis Using a Novel Serum Profiling Platform: Potential Involvement of the VWF/ADAMTS13 Axis.

It is important to develop minimally invasive biomarker platforms to help in the identification and monitoring of patients with Alzheimer's disease (AD). Assisting in the understanding of biochemical mechanisms as well as identifying potential novel biomarkers and therapeutic targets would be an added benefit of such platforms. This study utilizes a simplified and novel serum profiling platform, using mass spectrometry (MS), to help distinguish AD patient groups (mild and moderate) and controls, as well as to aid in understanding of biochemical phenotypes and possible disease development. A comparison of discriminating sera mass peaks between AD patients and control individuals was performed using leave one [serum sample] out cross validation (LOOCV) combined with a novel peak classification valuation (PCV) procedure. LOOCV/PCV was able to distinguish significant sera mass peak differences between a group of mild AD patients and control individuals with a p value of 10-13. This value became non-significant (p = 0.09) when the same sera samples were randomly allocated between the two groups and reanalyzed by LOOCV/PCV. This is indicative of physiological group differences in the original true-pathology binary group comparison. Similarities and differences between AD patients and traumatic brain injury (TBI) patients were also discernable using this novel LOOCV/PCV platform. MS/MS peptide analysis was performed on serum mass peaks comparing mild AD patients with control individuals. Bioinformatics analysis suggested that cell pathways/biochemical phenotypes affected in AD include those involving neuronal cell death, vasculature, neurogenesis, and AD/dementia/amyloidosis. Inflammation, autoimmunity, autophagy, and blood-brain barrier pathways also appear to be relevant to AD. An impaired VWF/ADAMTS13 vasculature axis with connections to F8 (factor VIII) and LRP1 and NOTCH1 was indicated and is proposed to be important in AD development.

Identification of a novel putative pancreatic stem/progenitor cell marker DCAMKL-1 in normal mouse pancreas.

Stem cells are critical in maintaining adult homeostasis and have been proposed to be the origin of many solid tumors, including pancreatic cancer. Here we demonstrate the expression patterns of the putative intestinal stem cell marker DCAMKL-1 in the pancreas of uninjured C57BL/6 mice compared with other pancreatic stem/progenitor cell markers. We then determined the viability of isolated pancreatic stem/progenitor cells in isotransplantation assays following DCAMKL-1 antibody-based cell sorting. Sorted cells were grown in suspension culture and injected into the flanks of athymic nude mice. Here we report that DCAMKL-1 is expressed in the main pancreatic duct epithelia and islets, but not within acinar cells. Coexpression was observed with somatostatin, NGN3, and nestin, but not glucagon or insulin. Isolated DCAMKL-1+ cells formed spheroids in suspension culture and induced nodule formation in isotransplantation assays. Analysis of nodules demonstrated markers of early pancreatic development (PDX-1), glandular epithelium (cytokeratin-14 and Ep-CAM), and isletlike structures (somatostatin and secretin). These data taken together suggest that DCAMKL-1 is a novel putative stem/progenitor marker, can be used to isolate normal pancreatic stem/progenitors, and potentially regenerates pancreatic tissues. This may represent a novel tool for regenerative medicine and a target for anti-stem cell-based therapeutics in pancreatic cancer.

Doublecortin and CaM kinase-like-1 and leucine-rich-repeat-containing G-protein-coupled receptor mark quiescent and cycling intestinal stem cells, respectively.

It is thought that small intestinal epithelia (IE) undergo continuous self-renewal primarily due to their population of undifferentiated stem cells. These stem cells give rise to transit amplifying (daughter/progenitor) cells, which can differentiate into all mature cell types required for normal gut function. Identification of stem cells in IE is paramount to fully understanding this renewal process. One major obstacle in gastrointestinal stem cell biology has been the lack of definitive markers that identify small intestinal stem cells (ISCs). Here we demonstrate that the novel putative ISC marker doublecortin and CaM kinase-like-1 (DCAMKL-1) is predominantly expressed in quiescent cells in the lower two-thirds of intestinal crypt epithelium and in occasional crypt-based columnar cells (CBCs). In contrast, the novel putative stem cell marker leucine-rich-repeat-containing G-protein-coupled receptor (LGR5) is observed in rapidly cycling CBCs and in occasional crypt epithelial cells. Furthermore, functionally quiescent DCAMKL-1+ crypt epithelial cells retain bromo-deoxyuridine in a modified label retention assay. Moreover, we demonstrate that DCAMKL-1 is a cell surface expressing protein; DCAMKL-1+ cells, isolated from the adult mouse small intestine by fluorescence activated cell sorting, self-renew and ultimately form spheroids in suspension culture. These spheroids formed glandular epithelial structures in the flanks of athymic nude mice, which expressed multiple markers of gut epithelial lineage. Thus, DCAMKL-1 is a marker of quiescent ISCs and can be distinguished from the cycling stem/progenitors (LGR5+). Moreover, DCAMKL-1 can be used to isolate normal small intestinal stem cells and represents a novel research tool for regenerative medicine and cancer therapy.

Systemic molecular and cellular changes induced in rats upon inhalation of JP-8 petroleum fuel vapor.

Limited information is available regarding systemic changes in mammals associated with exposures to petroleum/hydrocarbon fuels. In this study, systemic toxicity of JP-8 jet fuel was observed in a rat inhalation model at different JP-8 fuel vapor concentrations (250, 500, or 1000 mg/m(3), for 91 days). Gel electrophoresis and mass spectrometry sequencing identified the alpha-2 microglobulin protein to be elevated in rat kidney in a JP-8 dose-dependent manner. Western blot analysis of kidney and lung tissue extracts revealed JP-8 dependent elevation of inducible heat shock protein 70 (HSP70). Tissue changes were observed histologically (hematoxylin and eosin staining) in liver, kidney, lung, bone marrow, and heart, and more prevalently at medium or high JP-8 vapor phase exposures (500-1000 mg/m(3)) than at low vapor phase exposure (250 mg/m(3)) or non-JP-8 controls. JP-8 fuel-induced liver alterations included dilated sinusoids, cytoplasmic clumping, and fat cell deposition. Changes to the kidneys included reduced numbers of nuclei, and cytoplasmic dumping in the lumen of proximal convoluted tubules. JP-8 dependent lung alterations were edema and dilated alveolar capillaries, which allowed clumping of red blood cells (RBCs). Changes in the bone marrow in response to JP-8 included reduction of fat cells and fat globules, and cellular proliferation (RBCs, white blood cells-WBCs, and megakaryocytes). Heart tissue from JP-8 exposed animals contained increased numbers of inflammatory and fibroblast cells, as well as myofibril scarring. cDNA array analysis of heart tissue revealed a JP-8 dependent increase in atrial natriuretic peptide precursor mRNA and a decrease in voltage-gated potassium (K+) ion channel mRNA.

Serum discrimination and phenotype assessment of coronary artery disease patents with and without type 2 diabetes prior to coronary artery bypass graft surgery.

Diabetes Mellitus (DM) accelerates coronary artery disease (CAD) and atherosclerosis, the causes of most heart attacks. The biomolecules involved in these inter-related disease processes are not well understood. This study analyzes biomolecules in the sera of patients with CAD, with and without type (T) 2DM, who are about to undergo coronary artery bypass graft (CABG) surgery. The goal is to develop methodology to help identify and monitor CAD patients with and without T2DM, in order to better understand these phenotypes and to glean relationships through analysis of serum biomolecules. Aorta, fat, muscle, and vein tissues from CAD T2DM patients display diabetic-related histologic changes (e.g., lipid accumulation, fibrosis, loss of cellularity) when compared to non-diabetic CAD patients. The patient discriminatory methodology utilized is serum biomolecule mass profiling. This mass spectrometry (MS) approach is able to distinguish the sera of a group of CAD patients from controls (p value 10-15), with the CAD group containing both T2DM and non-diabetic patients. This result indicates the T2DM phenotype does not interfere appreciably with the CAD determination versus control individuals. Sera from a group of T2DM CAD patients however are distinguishable from non-T2DM CAD patients (p value 10-8), indicating it may be possible to examine the T2DM phenotype within the CAD disease state with this MS methodology. The same serum samples used in the CAD T2DM versus non-T2DM binary group comparison were subjected to MS/MS peptide structure analysis to help identify potential biochemical and phenotypic changes associated with CAD and T2DM. Such peptide/protein identifications could lead to improved understanding of underlying mechanisms, additional biomarkers for discriminating and monitoring these disease conditions, and potential therapeutic targets. Bioinformatics/systems biology analysis of the peptide/protein changes associated with CAD and T2DM suggested cell pathways/systems affected include atherosclerosis, DM, fibrosis, lipogenesis, loss of cellularity (apoptosis), and inflammation.

A Comparative Study of Modern and Heirloom Wheat on Indicators of Gastrointestinal Health.

Wheat consumption has declined amid growing concerns about gluten-sensitivity. To determine if genetic manipulation of wheat contributes to systemic and localized gut inflammation, we compared the effects of the modern variety Gallagher and a blend of two heirloom varieties, Turkey and Kharkof, on measures of gut inflammation, structural characteristics, and barrier integrity under normal and Western diet (WD) conditions in C57BL/6 mice. Indicators of gut inflammation, including lymphocyte infiltration and cytokine expression, were largely unaffected by WD or wheat, although WD elevated interferon-γ (Ifng) and heirloom varieties modestly reduced interleukin-17 (Il17) in the context of WD. WD negatively affected jejunal villi structure, while the modern variety improved villi structure in the ileum. Relative mRNA and tight junction proteins and serum lipopolysaccharide binding protein were unaltered by WD or wheat. These findings indicate that the modern variety did not compromise barrier function or contribute to gut inflammation compared to its heirloom predecessor.

Evolution of Brunner gland hamartoma associated with Helicobacter pylori infection.

The pathogenesis of Brunner gland hamartoma of the duodenum is unknown. This case report describes the chronology of the development of Brunner gland hamartoma from Brunner gland hyperplasia over a 12-year interval. The study subject, a 64-year-old man with chronic iron deficiency anemia, underwent serial upper endoscopies during this period. Repeated endoscopies demonstrated the evolution of Brunner gland hyperplasia, as manifest endoscopically by a submucosal mass, to a pedunculated polyp with histologic features of Brunner gland hamartoma. The duodenal polypoid mass was removed by snare polypectomy. The patient also had a chronic Helicobacter pylori infection of the stomach. This report details the time-dependent evolution of Brunner gland hyperplasia to hamartoma in association with chronic gastric H. pylori infection.

Obscure GI bleeding due to gastrointestinal stromal tumor (GIST) diagnosed by capsule endoscopy.

Gastrointestinal stromal tumor (GIST) is a submucosal tumor which is most commonly found in the stomach and less commonly in small bowel. Small bowel GIST can be difficult to diagnose by conventional imaging and endoscopy techniques. We report a case of obscure GI bleeding due to a stromal tumor (GIST) of the jejunum diagnosed by video capsule endoscopy.

Upregulation of PSMD10 caused by the JMJD2A histone demethylase.

PSMD10, also known as gankyrin, is associated with the proteasome and has been shown to be an oncoprotein in the liver. Here, we report that PSMD10 expression is stimulated by the histone demethylase JMJD2A/KDM4A and its interaction partner, the ETV1 transcription factor, in LNCaP prostate cancer cells. Global analysis of expression patterns revealed that PSMD10 mRNA levels are positively correlated with those of both JMJD2A and ETV1. In human prostate tumors, PSMD10 is highly overexpressed at the protein level and correlates with JMJD2A overexpression; further, PSMD10 expression is enhanced in the prostates of transgenic JMJD2A mice. Moreover, PSMD10 is particularly overexpressed in high Gleason score prostate tumors. Downregulation of PSMD10 in LNCaP prostate cancer cells impaired their growth, indicating that PSMD10 may exert a pro-oncogenic function in the prostate. Lastly, we observed that PSMD10 expression is correlated to YAP1, a component of the Hippo signaling pathway and whose gene promoter is regulated by JMJD2A, and that PSMD10 can cooperate with YAP1 in stimulating LNCaP cell growth. Altogether, these data indicate that PSMD10 is a novel downstream effector of JMJD2A and suggest that inhibition of the JMJD2A histone demethylase by small molecule drugs may be effective to curtail the oncogenic activity of PSMD10 in various PSMD10-overexpressing tumors.

Histone demethylase JMJD2A drives prostate tumorigenesis through transcription factor ETV1.

Histone demethylase upregulation has been observed in human cancers, yet it is unknown whether this is a bystander event or a driver of tumorigenesis. We found that overexpression of lysine-specific demethylase 4A (KDM4A, also known as JMJD2A) was positively correlated with Gleason score and metastasis in human prostate tumors. Overexpression of JMJD2A resulted in the development of prostatic intraepithelial neoplasia in mice, demonstrating that JMJD2A can initiate prostate cancer development. Moreover, combined overexpression of JMJD2A and the ETS transcription factor ETV1, a JMJD2A-binding protein, resulted in prostate carcinoma formation in mice haplodeficient for the phosphatase and tensin homolog (Pten) tumor-suppressor gene. Additionally, JMJD2A cooperated with ETV1 to increase expression of yes associated protein 1 (YAP1), a Hippo pathway component that itself was associated with prostate tumor aggressiveness. ETV1 facilitated the recruitment of JMJD2A to the YAP1 promoter, leading to changes in histone lysine methylation in a human prostate cancer cell line. Further, YAP1 expression largely rescued the growth inhibitory effects of JMJD2A depletion in prostate cancer cells, indicating that YAP1 is a downstream effector of JMJD2A. Taken together, these data reveal a JMJD2A/ETV1/YAP1 axis that promotes prostate cancer initiation and that may be a suitable target for therapeutic inhibition.

Antitumor activity of SS(dsFv)PE38 and SS1(dsFv)PE38, recombinant antimesothelin immunotoxins against human gynecologic cancers grown in organotypic culture in vitro.

PURPOSE: Mesothelin, a cell surface glycoprotein overexpressed in ovarian cancer, mesotheliomas, and some squamous cell carcinomas, is an attractive candidate for targeted therapy because it is not shed in significant amounts into the bloodstream and is not present in significant amounts on normal human tissues except for mesothelial cells. The objective of this study was to determine the antitumor activity of SS1(dsFv)PE38, a recombinant antimesothelin immunotoxin, against human gynecologic tumors grown in short-term culture in vitro. EXPERIMENTAL DESIGN: Tumor cells obtained from primary cultures of five ovarian and one cervical tumor were mixed with an equal proportion of NIH-3T3 fibroblasts and plated inside collagen gels in tissue culture plates. After 4-7 days of growth, these organotypic cultures were treated with media alone, SS1(dsFv)PE38, and a control immunotoxin RFB4(dsFv)PE38, which targets the CD22 antigen not present on gynecologic tumors, every other day x 3. The organotypic culture gels were then formalin fixed, paraffin embedded, and evaluated for immunotoxin sensitivity using light microscopic examination of H&E-stained slides and also evaluated for apoptosis using the terminal deoxynucleotidyl transferase-mediated nick end labeling assay. RESULTS: Tumors expressing mesothelin showed a significant dose-dependent sensitivity to SS1(dsFv)PE38 even at concentrations as low as 1 ng/ml, whereas no antitumor activity was seen at 100 ng/ml in tumors that did not express mesothelin. This activity was specifically attributable to mesothelin targeting because RFB4 (dsFv)-PE38 had no activity against mesothelin-expressing tumors. CONCLUSIONS: These results demonstrate that ovarian and cervical tumor cells obtained from patients can be grown in short-term culture using an organotypic culture model. Our results also show low concentrations of an immunotoxin targeting mesothelin is cytotoxic to mesothelin-expressing human tumors by inducing apoptosis.

Dietary Pectin Increases Intestinal Crypt Stem Cell Survival following Radiation Injury.

Gastrointestinal (GI) mucosal damage is a devastating adverse effect of radiation therapy. We have recently reported that expression of Dclk1, a Tuft cell and tumor stem cell (TSC) marker, 24h after high dose total-body gamma-IR (TBI) can be used as a surrogate marker for crypt survival. Dietary pectin has been demonstrated to possess chemopreventive properties, whereas its radioprotective property has not been studied. The aim of this study was to determine the effects of dietary pectin on ionizing radiation (IR)-induced intestinal stem cell (ISC) deletion, crypt and overall survival following lethal TBI. C57BL/6 mice received a 6% pectin diet and 0.5% pectin drinking water (pre-IR mice received pectin one week before TBI until death; post-IR mice received pectin after TBI until death). Animals were exposed to TBI (14 Gy) and euthanized at 24 and 84h post-IR to assess ISC deletion and crypt survival respectively. Animals were also subjected to overall survival studies following TBI. In pre-IR treatment group, we observed a three-fold increase in ISC/crypt survival, a two-fold increase in Dclk1+ stem cells, increased overall survival (median 10d vs. 7d), and increased expression of Dclk1, Msi1, Lgr5, Bmi1, and Notch1 (in small intestine) post-TBI in pectin treated mice compared to controls. We also observed increased survival of mice treated with pectin (post-IR) compared to controls. Dietary pectin is a radioprotective agent; prevents IR-induced deletion of potential reserve ISCs; facilitates crypt regeneration; and ultimately promotes overall survival. Given the anti-cancer activity of pectin, our data support a potential role for dietary pectin as an agent that can be administered to patients receiving radiation therapy to protect against radiation-induces mucositis.