Necrotic Regions Research Articles

Cell proliferation, drug distribution and therapeutic effects in relation to the vascular system of solid tumours.

In this perspective, the authors summarise some properties of the solid tumour micro-environment that have been explored during the last 55 years. It is well established that the concentrations of nutrients, including oxygen, decrease with increasing distance from tumour blood vessels, and that low extracellular pH is found in nutrient-poor regions. Cell proliferation is dependent on nutrient metabolites and decreases in regions distal from patent blood vessels. Proliferating cells cause migration of neighbouring cells further from blood vessels where they may die, and their breakdown products pass into regions of necrosis. Anticancer drugs reach solid tumours via the vascular system and establish concentration gradients such that drug concentration within tumours may be quite variable. Treatment with chemotherapy such as doxorubicin or docetaxel can kill well-nourished proliferating cells close to blood vessels, thereby interrupting migration toward necrotic regions and lead to re-oxygenation and renewed proliferation of distal cells, as can occur with radiotherapy. This effect leads to the paradox that cancer treatment can rescue cells that were destined to die in the untreated tumour. Renewed and sometimes accelerated repopulation of surviving tumour cells can counter the effects of cell killing from repeated treatments, leading to tumour shrinkage and regrowth without changes in the intrinsic sensitivity of cells to the administered treatment. Strategies to prevent these effects include the combined use of chemotherapy with agents that selectively kill hypoxic tumour cells, including inhibitors of autophagy, since this is a process that may allow recycling of cellular macromolecules from dying cells and improve their survival.

Multi-dimensional modeling of nanoparticles transportation from capillary bed into the tumor microenvironment

In this study, we examined the extravasation of pharmaceutical inorganic nanoparticles (NPs) with a new approach from the leaky endothelium of tumor microvasculature (TMV) into the tumor microenvironment (TME) multi-dimensionally. We proposed a combination of prevailing macroscopic and microscopic methods and addressed the effect of interstitial fluid (IF) retention in solid tumor as an imperative parameter in drug delivery modeling. The Navier-Stokes equations and Darcy's law were utilized for blood flow and porous media, and the Starling's law was brought in for coupling effect. The blood flow was simulated as a non-Newtonian fluid alongside the Newtonian IF. We applied the Galerkin finite element method for the simulations. Our parametric study includes examining the effect of IF retention and TMV pressure on the distribution of tumor interstitial fluid pressure (TIFP), NPs concentration, and diameter on the penetration process, together with the time effect, on two-dimensional (2D) delivery of NPs. Our findings indicate that the IF retention in tumor cells increases TIFP depending on the amount of TMV pressure and IF retained. In addition to doubling pressure in the tumor necrotic region rather than the rest of TME, it enhances the TIFP which is an important parameter in drug delivery to solid tumors. By decreasing pressure drop within the TMV, pressure distribution within the TME becomes more uniform, creating a better condition for homogeneous penetration of NPs. Increasing both inlet pressure and NPs concentration leads to a nonlinear increase in the average concentration of tumor. Decreasing the diameter of NPs increases the penetration of NPs with a higher ratio in the TME.

Distal phalanx intraosseous epidermoid inclusioncyst: A rare thing!

Pathological structures called epidermoid bone inclusion cysts are surrounded by a layer of stratified squamous epithelium that contains keratin debris. They go by the name epidermal bone cysts as well. Intraosseous epidermoid cysts are uncommon lesions that can develop as a result of trauma (puncture wound or pressure erosion). They typically affect the toes, phalanges, and head. The distal phalanx of the fingers is where phalangeal involvement most frequently occurs. Despite the fact that the cause of intraosseous epidermal inclusion cysts is still unknown, the majority of patients do recall a prior traumatic event, supporting the post-traumatic origin theory. Following digital trauma or surgery, it is hypothesised that surface epithelial cells are pushed into the underlying osseous compartment.Following the initiating event, symptoms may start to appear months to years later. It is challenging to distinguish intraosseous epidermoid inclusion cysts on radiographs from other radiolucent lesions, necessitating tissue diagnosis.We present a case of a 45-year-old man with right middle finger distal phalanx edoema for five months and a known history of minor blunt trauma. A well-defined expansile hypodense lytic lesion with eccentric phalanx erosion was discovered during radiological analysis. A creamy substance was found inside the lesion after surgery, and it was later determined by histology to be an epidermoid inclusion cyst.Gross examination of the surgical specimen indicated a cystic lesion with significant necrotic regions and pale, creamy material. A burst intraosseous epidermoid inclusion cyst was discovered upon microscopic inspection and was effectively removed.

Recognition of necrotic regions in MRI images of chronic spinal cord injury based on superpixel

Background and objectiveThe cystic cavity and its surrounding dense glial scar formed in chronic spinal cord injury (SCI) hinder the regeneration of nerve axons. Accurate location of the necrotic regions formed by the scar and the cavity is conducive to eliminate the re-growth obstacles and promote SCI treatment. This work aims to realize the accurate and automatic location of necrotic regions in the chronic SCI magnetic resonance imaging (MRI). MethodsIn this study, a method based on superpixel is proposed to identify the necrotic regions of spinal cord in chronic SCI MRI. Superpixels were obtained by a simple linear iterative clustering algorithm, and feature sets were constructed from intensity statistical features, gray level co-occurrence matrix features, Gabor texture features, local binary pattern features and superpixel areas. Subsequently, the recognition effects of support vector machine (SVM) and random forest (RF) classification model on necrotic regions were compared from accuracy (ACC), positive predictive value (PPV), sensitivity (SE), specificity (SP), Dice coefficient and algorithm running time. ResultsThe method is evaluated on T1- and T2-weighted MRI spinal cord images of 24 adult female Wistar rats. And an automatic recognition method for spinal cord necrosis regions was established based on the SVM classification model finally. The recognition results were 1.00±0.00 (ACC), 0.89±0.09 (PPV), 0.88±0.12 (SE), 1.00±0.00 (SP) and 0.88±0.07 (Dice), respectively. ConclusionsThe proposed method can accurately and noninvasively identify the necrotic regions in MRI, which is helpful for the pre-intervention assessment and post-intervention evaluation of chronic SCI research and treatments, and promoting the clinical transformation of chronic SCI research.

NIMG-50. ASSOCIATION BETWEEN SALINITY, ACIDITY, DIFFUSIVITY, AND HYPOXIA IN HUMAN GLIOMAS USING MULTI-NUCLEAR MRI

Abstract INTRODUCTION Sodium MRI has been recently explored in brain tumors to potentially reveal complementary information with proton MRI about the tumor microenvironment. However, there remains limited investigation combining sodium and quantitative proton MRI techniques. This pilot study explored the associations of sodium MRI with diffusion-, pH-, and hypoxia-weighted MRI biomarkers in gliomas. METHODS Eleven patients with gliomas (n=8 IDH-wild-type; n=3 IDH-mutant) who obtained sodium, anatomical, diffusion-, pH-, and hypoxia-weighted MRI were studied. All images were obtained on a 3T Siemens Prisma with a dedicated multi-nuclear head coil. Regions-of-interest were segmented on the contrast-enhancing (CE) (n=10), FLAIR (n=11), and necrotic regions (n=9). Sodium values were normalized to the mean values of the eyes. Median sodium, apparent diffusion coefficient (ADC), ADC(L) from bimodal histogram analyses, MTRasym (acidity), and R2’ (hypoxia) values were obtained. RESULTS There was increased sodium in necrosis compared to FLAIR regions (mean difference=0.24; P/i>< 0.05) and compared to CE regions (mean difference=0.17; P/i>=0.07). There were significant positive correlations between sodium and ADC in CE (R=0.94; P/i>< 0.0001) and FLAIR regions (ρ=0.77; P/i>< 0.01), but not in necrosis (R=0.44; P/i>=0.24). There was also a significant positive correlation with ADC(L) in CE regions (R=0.90; P< 0.001) but not in FLAIR regions (ρ=0.50; P/i>=0.12). Furthermore, there was a significant positive correlation between sodium and MTRasym in necrosis (R=0.74; P/i>< 0.05) and a positive trend in CE regions (R=0.55; P=0.10). There was also a negative trend between sodium and R2’ in FLAIR regions (ρ=-0.58; P/i>=0.11). CONCLUSIONS Because ADC and ADC(L) are inversely related to cell density, increased sodium in gliomas may reflect increased extracellular space stemming from lower cell density, as sodium concentration is higher extracellularly. Positive associations between sodium and acidity as well as negative associations between sodium and hypoxia may reflect alterations in coupled sodium-pH and sodium-hypoxia homeostasis in gliomas.

Visible near-infrared hyperspectral imaging and supervised classification for the detection of small intestinal necrosis tissue in vivo.

Complete recognition of necrotic areas during small bowel tissue resection remains challenging due to the lack of optimal intraoperative aid identification techniques. This research utilizes hyperspectral imaging techniques to automatically distinguish normal and necrotic areas of small intestinal tissue. Sample data were obtained from the animal model of small intestinal tissue of eight Japanese large-eared white rabbits developed by experienced physicians. A spectral library of normal and necrotic regions of small intestinal tissue was created and processed using six different supervised classification algorithms. The results show that hyperspectral imaging combined with supervised classification algorithms can be a suitable technique to automatically distinguish between normal and necrotic areas of small intestinal tissue. This new technique could aid physicians in objectively identify normal and necrotic areas of small intestinal tissue.

Morphological description of infective larval stage of Physaloptera (Spirurida: Physalopteridae), and histological lesions in the paratenic host Leptodactylus macrosternum (Anura: Leptodactylidae) in Caatinga biome, Brazil

The present study aimed to describe the infective larval stage of Physaloptera sp. parasitizing Leptodactylus macrosternum and the microscopic lesions of these larvae in the stomach wall. Forty-five specimens of L. macrosternum were collected during the rainy season in May 2018, in the municipality of Petrolina, sub-middle São Francisco region, state of Pernambuco, Brazil. Twenty-seven infective larval stage (L3) specimens of Physaloptera sp. were collected attached in the stomach mucosa of 11 specimens (24.4%) of L. macrosternum. No other larval stages (L4) or adult of Physaloptera was found among the necropsied hosts. The stomach’s L3 attachment site showed macroscopic and histological lesions such as hyperaemic and ulcerated sites, mucous tunic necrotic regions, and inflammatory infiltrate eosinophilic. This is the first morphological study of Physaloptera infective larvae parasitizing L. macrosternum, and the first record of this paratenic host in the Caatinga biome. Additionally, it is also the first histopathological study of lesions caused by infective larvae of Physaloptera in this host species.

Three-Dimensional Mass Spectrometry Imaging Reveals Distributions of Lipids and the Drug Metabolite Associated with the Enhanced Growth of Colon Cancer Cell Spheroids Treated with Triclosan.

The application of mass spectrometry imaging (MSI) to explore the responses of cancer cell spheroids (CCS) after treatment of exogenous molecules has attracted growing attention. Increasing studies have utilized MSI to image the two-dimensional distributions of exogenous and endogenous molecules in planar CCS sections. However, because CCS are volumetric and heterogenous, maintaining their three-dimensional (3D) information is essential for acquiring a better understanding of the tumor microenvironment and mechanisms of action of exogenous molecules. Here, an established method of 3D MSI was applied to distinguish the distributions of triclosan sulfate and endogenous lipids in three microregions of colon CCS with an enhanced growth induced by the treatment of triclosan, a common antimicrobial agent. The results of 3D MSI showed that triclosan sulfate gradually accumulated from the periphery to the entire structure of CCS and finally localized in the core region. Spatial lipidomics analysis revealed that the upregulated phosphatidylethanolamine (fold change (FD) = 1.26, p = 0.0021), phosphatidylinositol (FD = 1.17, p = 0.0180), and phosphatidylcholine (FD = 1.22, p = 0.0178) species mainly distributed in the outer proliferative region, while the upregulated sphingomyelin (FD = 1.18, p = 0.024) species tended to distribute in the inner necrotic region. Our results suggest that a competitive mechanism between inhibiting and promoting CCS growth might be responsible for the proliferation of CCS treated with triclosan.

CEST MR fingerprinting (CEST-MRF) for brain tumor quantification using EPI readout and deep learning reconstruction.

To develop a clinical CEST MR fingerprinting (CEST-MRF) method for brain tumor quantification using EPI acquisition and deep learning reconstruction. A CEST-MRF pulse sequence originally designed for animal imaging was modified to conform to hardware limits on clinical scanners while keeping scan time under 2min. Quantitative MRF reconstruction was performed using a deep reconstruction network (DRONE) to yield the water relaxation and chemical exchange parameters. The feasibility of the six parameter DRONE reconstruction was tested in simulations using a digital brain phantom. A healthy subject was scanned with the CEST-MRF sequence, conventional MRF and CEST sequences for comparison. Reproducibility was assessed via test-retest experiments and the concordance correlation coefficient calculated for white matter and gray matter. The clinical utility of CEST-MRF was demonstrated on four patients with brain metastases in comparison to standard clinical imaging sequences. Tumors were segmented into edema, solid core, and necrotic core regions and the CEST-MRF values compared to the contra-lateral side. DRONE reconstruction of the digital phantom yielded a normalized RMS error of ≤7% for all parameters. The CEST-MRF parameters were in good agreement with those from conventional MRF and CEST sequences and previous studies. The mean concordance correlation coefficient for all six parameters was 0.98 ± 0.01 in white matter and 0.98 ± 0.02 in gray matter. The CEST-MRF values in nearly all tumor regions were significantly different (P=0.05) from each other and the contra-lateral side. Combination of EPI readout and deep learning reconstruction enabled fast, accurate and reproducible CEST-MRF in brain tumors.

S2.4a Pythiosis: An emerging disease in Hong Kong

S2.4 Veterinary mycology research, September 21, 2022, 3:00 PM - 4:30 PMOomycosis is an emerging disease of humans and animals caused by oomycetes in the Stramenopiles-Alveolata-Rhizaria super group, mainly Pythium insidiosum and occasionally Lagenidium giganteum or Paralagenidum species. In surface freshwater, oomycetes produce motile biflagellate asexual zoospores with marked chemotactic attraction to epithelial surfaces of vertebrate hosts. Infection is the result of encystation and invasion of damaged skin or gastrointestinal mucosa.Of ∼ 4200 cases of pythiosis reported globally between 1980 and 2021 only ∼ 20% involved humans while 80% involved animals, mainly horses, dogs, and cattle. Most human cases occur in India and Thailand, whereas most animal infections were reported in the United States and Brazil. Pythiosis has been reported in mainland China, but the burden of the disease is low and comprises <1% of overall cases in humans.Neither pythiosis nor lagenidiosis has been previously reported in humans or animals in Hong Kong. From January 2018 to January 2022, the Veterinary Diagnostic Laboratory of City University of Hong Kong diagnosed 10 cases of oomycosis (5 canine, 5 feline) after identification of non-parallel walled, irregularly branching, and poorly septate hyphae in the center of necrotic regions of histological sections of formalin-fixed paraffin-embedded tissues (FFPET). Species identity was confirmed by PCR and sequencing of 28S rDNA from DNA extracts of FFPET. There were 8 cases of P. insidiosum and 2 of L. giganteum infection. Serum ELISA was positive for Pythium antibodies in 5/6 cases tested and negative for Pythium/Lagenidium/Paralagenidum antibodies in a German shepherd dog (GSD) with disseminated disease caused by L. giganteum.Affected dogs were young to middle-aged at presentation (9 months to 5 years old). Two dogs had focal cutaneous infections, two had extensive gastrointestinal involvement, and the GSD had disseminated disease with cutaneous, mediastinal, and abdominal involvement.Affected cats were young (8 weeks to 18 months) and presented with subcutaneous/cutaneous disease. Three cats had a distinctive perianal ring of bulging subcutaneous granulation tissue, including one that also had an ulcerated, proliferative and necrotic lesion involving two adjacent hind-limb digits. One cat had facial subcutaneous swelling with mandibular lymph node enlargement and the remaining cat presented with extensive circumferential swelling of one hind limb from the distal paw to the mid-stifle.All cats tested negative for the Feline leukemia virus and Feline immunodeficiency virus. Traumatic or surgical wounds preceding infection were identified in a kitten caught in a rodent glue-trap with skin wounds, in a cat with facial involvement that had an injured globe surgically enucleated, and in a dog with cutaneous pythiosis that had chronic dermatitis.Treatment data were available for one canine case. The GSD with lagenidiosis was treated with combination antimicrobial therapy including voriconazole, terbinafine, minocycline, and azithromycin. The dog responded poorly. Mefenoxam was substituted for voriconazole and hyperbaric oxygen therapy was administered. After initial response, the dog succumbed 4 months from diagnosis. We have had success with the treatment of four feline cases using combination therapy including surgical debridement, immunotherapy with a Pythium vaccine, and combinations of antifungal drugs (posaconazole and terbinafine), and/or antimicrobials (doxycycline/minocycline and azithromycin).

PL01.6.A Radiomics outperforms semantic features for prediction of response to stereotactic radiosurgery in brain metastases

Abstract Background Brain metastases show different patterns of contrast enhancement, potentially reflecting hypoxic and necrotic tumor regions with reduced radiosensitivity. An objective evaluation of these patterns might allow a prediction of response to radiotherapy. We therefore investigated the potential of MRI radiomics in comparison with the visual assessment of semantic features to predict early response to stereotactic radiosurgery in patients with brain metastases. Material and Methods In this retrospective study, 150 patients with 308 brain metastases from solid tumors (NSCLC in 53% of patients) treated by stereotactic radiosurgery (single dose of 17-20 Gy) were evaluated. The response of each metastasis (partial or complete remission vs. stabilization or progression) was assessed within 180 days after radiosurgery. Patterns of contrast enhancement in the pre-treatment T1-weighted MR images were either visually classified (homogenous, heterogeneous, necrotic ring-like) or subjected to a radiomics analysis. Random forest models were optimized by cross-validation and evaluated in a hold-out test data set (30% of metastases). Results In total, 221/308 metastases (72%) responded to radiosurgery. The optimal radiomics model comprised 10 features and outperformed the model solely based on semantic features in the test data set (AUC, 0.71 vs. 0.56; accuracy, 69% vs. 54%). The diagnostic performance could be further improved by combining semantic and radiomics features resulting in an AUC of 0.74 and an accuracy of 75% in the test data set. Conclusion The developed radiomics model allowed prediction of early response to radiosurgery in patients with brain metastases and outperformed the visual assessment of patterns of contrast enhancement.

Gram Negative Bacteria Key Role in the Therapy of Cancer

Bacteria promoting cancer development and tumor progression are gramnegative bacteria like Salmonella’s species and can play key role in the therapy of cancer. As tumor site are oxygenated so it when systematically gramnegative bacteria rushed into the tumor site, then their necrotic region produced by the reduction of oxygen and declination of nutrients. In the patients of lung cancer, NSCLC mostly, diagnosing the persons which suffer with NSCLC showed that in advanced stage gram negative bacteria play major role in the infection of patients with (NSCLC). In NSCLC patients’ infection of lungs along with gram negative bacteria are usually issues after having surgical operation. Assembling proof specify a participation of gram-negative bacteria within the non-small cell lung cancer succession, fundamental processes endure unrevealed. This article would explain the consequence of GN bacteria on the progression of tumor tissues of NSCLC victims. After observance it is concluded that the process of infecting by gram negative bacteria predicted in preliminary stages. The increment and metastasis of non-small cell lung cells caused by incubation by NSCLC with Gram negative bacteria. The mechanism explored that Gram negative bacteria operated tall-like receptor no, 4 which signaling to NSCLC cells, which caused to increase the production of messenger-RNA and expression of protein of interleukin 33 by MyD88-passageway. The destruction of IL-33 revokes the participation of gram-negative bacteria to non-small cell lung cancer succession by controlling cancer metabolic occupation. The increment of IL-33 expression, CD133 expression was directly proportional to TLR4 expression. This information explains the molecular technique of gramnegative bacteria moderate tumor succession.

Lipidomic comparison of 2D and 3D colon cancer cell culture models.

Altered lipid metabolism is one of the hallmarks of cancer. Cellular proliferation and de novo synthesis of lipids are related to cancer progression. In this study, we evaluated the lipidomic profile of two‐dimensional (2D) monolayer and multicellular tumor spheroids from the HCT 116 colon carcinoma cell line. We utilized serial trypsinization on the spheroid samples to generate three cellular populations representing the proliferative, quiescent, and necrotic regions of the spheroid. This analysis enabled a comprehensive identification and quantification of lipids produced in each of the spheroid layer and 2D cultures. We show that lipid subclasses associated with lipid droplets form in oxygen‐restricted and acidic regions of spheroids and are produced at higher levels than in 2D cultures. Additionally, sphingolipid production, which is implicated in cell death and survival pathways, is higher in spheroids relative to 2D cells. Finally, we show that increased numbers of lipids composed of polyunsaturated fatty acids (PUFAs) are produced in the quiescent and necrotic regions of the spheroid. The lipidomic signature for each region and cell culture type highlights the importance of understanding the spatial aspects of cancer biology. These results provide additional lipid biomarkers in colon cancer cells that can be further studied to target pivotal lipid production pathways.

Microfluidic Model to Evaluate Astrocyte Activation in Penumbral Region following Ischemic Stroke.

Stroke is one of the main causes of death in the US and post-stroke treatment options remain limited. Ischemic stroke is caused by a blood clot that compromises blood supply to the brain, rapidly leading to tissue death at the core of the infarcted area surrounded by a hypoxic and nutrient-starved region known as the penumbra. Recent evidence suggests that astrocytes in the penumbral region play a dual role in stroke response, promoting further neural and tissue damage or improving tissue repair depending on the microenvironment. Thus, astrocyte response in the hypoxic penumbra could promote tissue repair after stroke, salvaging neurons in the affected area and contributing to cognitive recovery. However, the complex microenvironment of ischemic stroke, characterized by gradients of hypoxia and nutrients, poses a unique challenge for traditional in vitro models, which in turn hinders the development of novel therapies. To address this challenge, we have developed a novel, polystyrene-based microfluidic device to model the necrotic and penumbral region induced by an ischemic stroke. We demonstrated that when subjected to hypoxia, and nutrient starvation, astrocytes within the penumbral region generated in the microdevice exhibited long-lasting, significantly altered signaling capacity including calcium signaling impairment.

Abstract 1202: A repository of PDX histology images for exploring spatial heterogeneity and cancer dynamics

Abstract Patient-derived xenografts (PDXs) recapitulate intratumoral spatial heterogeneity and simulate a tumor microenvironment in which human immune and stromal cells in the PDX are replaced over passages by murine cells partially lacking immune function. Histological imaging enables exploring the spatial heterogeneity and dynamics of cancer, stromal, and immune cell interactions as correlates of tumor stage and therapeutic response over passages. We created a repository of curated, haematoxylin and eosin (H&amp;E) images as a community resource for addressing these questions. Images were generated at five sites within the NCI’s PDX Development and Trial Centers Research Network (PDXNet) and the NCI Patient-Derived Models Repository. Over 900 images, including 739 from PDXs and 190 from paired patients, are hosted on the Seven Bridges Genomics Cancer Genomics Cloud. They represent 42 cancer subtypes, including breast cancer (n=134), colon adenocarcinoma (COAD; n=94), pancreatic cancer (n=87), lung adenocarcinoma (LUAD; n=80), melanoma (n=71), and squamous cell lung cancer (LUSC; n=65). Paired human/PDX images are available for each of these cancers. Human and/or PDX images generated following patient treatment are available for 37 of the subtypes. Most images are from early passages (P0: 158; P1: 292; P2: 152; P3: 69; &amp;gt;P3: 55). Annotations include sex, age, race, ethnicity, and, for most images, pathological assessment of tissue-level percent cancer, stromal, and necrotic cell content (n=639) and tumor stage (n=650). RNA and exome sequencing data are available for 99 and 228 images, respectively, matched at the patient or sample level. Quality control was performed using HistoQC. Cells were segmented and labeled as neoplastic, necrotic, immune, stromal, or other using Hover-Net and predictions of total neoplastic cell area correlated with whole-slide pathological assessment of cancer cell percentage (COAD: r=0.51; LUSC: r=0.59). HD-Staining, another classification approach, was applied to a subset of images and our clinical annotations will facilitate validation of this and related methods. Features of 512 x 512 pixel tiles were computed using the Inception V3 convolutional neural network pre-trained on ImageNet. Unsupervised clustering of these features demonstrate inter-patient heterogeneity within pathologist-annotated tumor regions. A classifier developed using pathologist-annotated cancer, stromal, and necrotic regions and trained on the features in LUSC images (n=10 images) achieved a cross-validation accuracy of 96% for cancer tiles across (n=5) LUAD images. Accuracy was lower for stromal classification (90%), likely reflecting current limitations of our small, but growing, labeled training set. Our repository of clinically-annotated PDX H&amp;E images should aid the community in studying spatial heterogeneity and in training deep learning-based image analysis methods. Citation Format: Brian S. White, Xingyi Woo, Soner Koc, Todd Sheridan, Steven B. Neuhauser, Akshat M. Savaliya, Lacey E. Dobrolecki, John D. Landua, Matthew H. Bailey, Maihi Fujita, Kurt W. Evans, Bingliang Fang, Junya Fujimoto, Maria Gabriela Raso, Shidan Wang, Guanghua Xiao, Yang Xie, Sherri R. Davies, Ryan C. Fields, R Jay Mashl, Jacqueline L. Mudd, Yeqing Chen, Min Xiao, Xiaowei Xu, Melinda G. Hollingshead, Shahanawaz Jiwani, PDXNet Consortium, Yvonne A. Evrard, Tiffany A. Wallace, Jeffrey A. Moscow, James H. Doroshow, Nicholas Mitsiades, Salma Kaochar, Chong-xian Pan, Moon S. Chen, Luis G. Carvajal-Carmona, Alana L. Welm, Bryan E. Welm, Michael T. Lewis, Ramaswamy Govindan, Li Ding, Shunqiang Li, Meenhard Herlyn, Michael A. Davies, Jack A. Roth, Funda Meric-Bernstam, Carol J. Bult, Brandi Davis-Dusenbery, Dennis A. Dean, Jeffrey H. Chuang. A repository of PDX histology images for exploring spatial heterogeneity and cancer dynamics [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 1202.

Modeling the Effect of Hyperoxia on the Spin-Lattice Relaxation Rate R1 of Tissues.

PurposeInducing hyperoxia in tissues is common practice in several areas of research, including oxygen‐enhanced MRI (OE‐MRI), which attempts to use the resulting signal changes to detect regions of tumor hypoxia or pulmonary disease. The linear relationship between PO2 and R1 has been reproduced in phantom solutions and body fluids such as vitreous fluid; however, in tissue and blood experiments, factors such as changes in deoxyhemoglobin levels can also affect the ΔR1.Theory and MethodsThis manuscript proposes a three‐compartment model for estimating the hyperoxia‐induced changes in R1 of tissues depending on B0, SO2, blood volume, hematocrit, oxygen extraction fraction, and changes in blood and tissue PO2. The model contains two blood compartments (arterial and venous) and a tissue compartment. This model has been designed to be easy for researchers to tailor to their tissue of interest by substituting their preferred model for tissue oxygen diffusion and consumption. A specific application of the model is demonstrated by calculating the resulting ΔR1 expected in healthy, hypoxic and necrotic tumor tissues. In addition, the effect of sex‐based hematocrit differences on ΔR1 is assessed.ResultsThe ΔR1 values predicted by the model are consistent with reported literature OE‐MRI results: with larger positive changes in the vascular periphery than hypoxic and necrotic regions. The observed sex‐based differences in ΔR1 agree with findings by Kindvall et al. suggesting that differences in hematocrit levels may sometimes be a confounding factor in ΔR1.ConclusionThis model can be used to estimate the expected tissue ΔR1 in oxygen‐enhanced MRI experiments.

Population-based retrospective analysis of response assessment criteria in patients with glioblastoma.

2041 Background: Patients with glioblastoma are often treated with radiation and chemotherapy following surgery. Disease recurrence often occurs early in the disease course and during initial therapy, yet assessment of treatment response with MRI is highly variable in some situations. We sought to describe the clinical and imaging assessment and outcomes of an unselected cohort of patients with glioblastoma following the publication of the Response Assessment in Neuro-Oncology criteria. Methods: Patients diagnosed with glioblastoma in Manitoba, Canada, from 2012-2018 were identified from the Manitoba Cancer Registry. Chart review was performed to identify treatments given and decisions made by the treating team, and imaging analysis was performed to assess based on RANO and mRANO criteria. Determination of progression versus pseudoprogression according to these criteria was performed using clinical decision-making and review of follow-up imaging for confirmation. At time of the response assessment visit, patients were assessed by a primary oncologist (Radiation or Medical) and were also discussed at multidisciplinary Case Conference (comprised of Medical and Radiation Oncology, Neurosurgery, Neuropathology, and Neuroradiology). Treatment decisions were made with patient and primary oncologist, guided by input from the Case Conference. Tumour measurements were performed both in 2D using Product of Perpendicular Diameter analysis (PPD) and 3D volumetric measurements with/without necrotic region. Overall Survival (OS) and Progression Free Survival (PFS) were estimated to evaluate the effectiveness of response assessments and Kaplan-Meier method was used to compare the time to progression resulted from RANO, mRANO, and clinical impression. Results: A total of 285 patients were identified with a pathological diagnosis of glioblastoma. Of those, 199 (35% male, 65% female) were treated with concurrent temozolomide and radiation (75% 60Gy and 25% &lt; 60Gy), and more than 90% went on to receive adjuvant temozolomide. Median Overall Survival of the 199 was 13.2 months. Of those treated with concurrent therapy, 122 (61%) had MRI studies with equivocal results within the first 6 months, with confirmatory MRI showing true progression in 73 (59.8%), pseudoprogression in 45 (36.9%), and 4 patients with undetermined outcome. Formal RANO and mRANO comparison is ongoing. Conclusions: Response assessment for patients with glioblastoma remains a frequent challenge despite the use of MRI and established response criteria, with more than half of patients having equivocal imaging changes and a high frequency of pseudoprogression.

A multimodal pipeline using NMR spectroscopy and MALDI-TOF mass spectrometry imaging from the same tissue sample.

NMR spectroscopy and matrix assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) are both commonly used to detect large numbers of metabolites and lipids in metabolomic and lipidomic studies. We have demonstrated a new workflow, highlighting the benefits of both techniques to obtain metabolomic and lipidomic data, which has realized for the first time the combination of these two complementary and powerful technologies. NMR spectroscopy is frequently used to obtain quantitative metabolite information from cells and tissues. Lipid detection is also possible with NMR spectroscopy, with changes being visible across entire classes of molecules. Meanwhile, MALDI MSI provides relative measures of metabolite and lipid concentrations, mapping spatial information of many specific metabolite and lipid molecules across cells or tissues. We have used these two complementary techniques in combination to obtain metabolomic and lipidomic measurements from triple-negative human breast cancer cells and tumor xenograft models. We have emphasized critical experimental procedures that ensured the success of achieving NMR spectroscopy and MALDI MSI in a combined workflow from the same sample. Our data show that several phospholipid metabolite species were differentially distributed in viable and necrotic regions of breast tumor xenografts. This study emphasizes the power of combined NMR spectroscopy-MALDI imaging to advance metabolomic and lipidomic studies.

Abstract A027: Exploring the effect of hypoxia and spatial interactions on the dynamics between gefitinib resistant and naïve NSCLC cell lines

Abstract Hypoxia and the development of spatially heterogeneous hypoxic and/or necrotic regions in non-small cell lung cancer (NSCLC) and other solid tumors is associated with chemotherapy and radiation resistance. One mechanism by which this could occur is through modification of the cell-cell interactions (or games) between the resistant and naïve cells within the tumor. Cell-cell interactions can modify the fitness of cells and thereby change the evolutionary dynamics of a tumor. Hypoxia may, in this way, change the game dynamics between cells and directly support maintenance of a population of resistant cells. To understand the mechanism by which hypoxic heterogeneity modulates evolutionary dynamics and therapy response, we combine computational modeling and in vitro experiments under a spatial hypoxia gradient. We utilize in-house game assay protocols to probe the evolutionary games between cell types. The experimental system is adapted from Carmona-Fontaine's MEMIC plate. This system allows us to create stable oxygen and nutrient gradients for 12 evolutionary replicates of NSCLC PC-9 cells. Fluorescence labeled gefitinib-resistant PC-9 cells and naïve parental PC-9 cells are co-cultured in a closed chamber with limited availability to oxygen and nutrient supply at one end. A green hypoxia probe is used to verify the establishment of a hypoxia gradient and a red Annexin V probe monitors apoptosis. Once microenvironmental gradients are established due to cellular consumption of oxygen and nutrients, images of cells are taken every 1.5 hours for 5 days. We carry out multiple experiments in which we vary the initial proportions of parental and resistant cells. Computationally, green and red fluorescence from the images captured by the microscopy system is quantified by an in-house image processing pipeline. We apply a random forest machine learning classifier, illumination correction, and object identification to each image to gather fluorescence counts for each well. These counts are used to compute the background rate of cell death and absolute vs. relative oxygen levels. The subsequent cell counts over time were used to calculate the growth rate (fitness) of the cell types in different environments and therefore the strength of environmental and frequency dependent interactions between the cell types. This framework allows for tightly coupled computational and in vitro experiments aimed at understanding and predicting the clinical implications of hypoxia resistance across a range of tumor types and microenvironments. We have measured the effect of hypoxia upon game interactions between gefinib-resistant and susceptible NSCLC cells. The evolutionary game changes with changing levels of hypoxia–and for the first time we are able to write down a continuous equation representing the game as a function of oxygen. Citation Format: Mina Dinh, Bezhou Feng, Jeff Maltas, Emily Dolson, Masahiro Hitomi, Steph Owen, Jacob Scott. Exploring the effect of hypoxia and spatial interactions on the dynamics between gefitinib resistant and naïve NSCLC cell lines [abstract]. In: Proceedings of the AACR Special Conference on the Evolutionary Dynamics in Carcinogenesis and Response to Therapy; 2022 Mar 14-17. Philadelphia (PA): AACR; Cancer Res 2022;82(10 Suppl):Abstract nr A027.

Iron- and erythropoietin-resistant anemia in a spontaneous breast cancer mouse model.

Anemia of cancer (AoC) with its multifactorial etiology and complex pathology is a poor prognostic indicator for cancer patients. One of the main causes of AoC is cancer-associated inflammation that activates mechanisms, commonly observed in anemia of inflammation, whereby functional iron deficiency and iron-restricted erythropoiesis are induced by increased hepcidin levels in response to raised levels of interleukin-6. So far only a few AoC mouse models have been described, and most of them did not fully recapitulate the interplay of anemia, increased hepcidin levels and functional iron deficiency in human patients. To test if the selection and the complexity of AoC mouse models dictates the pathology or if AoC in mice per se develops independently of iron deficiency, we characterized AoC in Trp53floxWapCre mice that spontaneously develop breast cancer. These mice developed AoC associated with high levels of interleukin-6 and iron deficiency. However, hepcidin levels were not increased and hypoferremia coincided with anemia rather than causing it. Instead, an early shift in the commitment of common myeloid progenitors from the erythroid to the myeloid lineage resulted in increased myelopoiesis and in the excessive production of neutrophils that accumulate in necrotic tumor regions. This process could not be prevented by either iron or erythropoietin treatment. Trp53floxWapCre mice are the first mouse model in which erythropoietin-resistant anemia is described and may serve as a disease model to test therapeutic approaches for a subpopulation of human cancer patients with normal or corrected iron levels who do not respond to erythropoietin.