Simultaneous stimulation of growth of malignant tumors with epithelioid and sarcomatous nature in experiment.

e23517 Background: The relevance of studying multiple primary malignant tumors (MPMTs) is determined by poor understanding of their pathogenesis. Our purpose was to create an experimental model of synchronous MPMTs with the stimulation of malignant growth of tumors with different histostructure. Methods: The study included 20 male BALB/c Nude mice. The main group included mice with simultaneous subcutaneous inoculation of tumors: murine B16/F10 melanoma (0.5 ml of suspension diluted 1:20 in saline solution) below the left scapula and rat sarcoma 45 (0.5 million tumor cells in 0.5 ml of saline solution) below the right scapula. Control groups included males with melanoma or sarcoma inoculated at the same dosage and volume as in the main group. Results: In the model of synchronous MPMTs, tumors appeared faster than in controls: melanoma–by 3 times, sarcoma–by 2 times; their volume was larger: melanoma–by 2.2 times, sarcoma–by 3.2 times. Melanoma metastasized, in addition to typical sites (the lungs, spleen, liver), into sarcoma 45 to the side adjacent to the chest, under the tumor node. The survival of mice with MPMTs was lower. The morphological structure of melanoma metastasis into sarcoma 45 was represented by large lamellar-rounded epithelium-like cells of melanosarcoma type with transparent cytoplasm and nuclei with a high frequency of pathological mitosis figures. Bundles of elongated spindle-shaped melanocytes with processes of the cytoplasm were determined in some melanoma areas, as well as alveolar and concentric structures. Conclusions: Synchronous subcutaneous inoculation of murine B16/F10 melanoma and rat sarcoma 45 to male BALB/c Nude mice increases their malignant potential due to an exchange of “structural information"; as a result, sarcoma acquires impulses of proliferative activity of melanoma, which, in turn, adapts and “mimics” a tumor into which it is going to metastasize.

Suppression of tumor development by another tumor in primary immunodeficiency in experiment.

e21583 Background: Multiple primary malignant tumors (MPMTs) are characterized by the presence of several primary neoplasms in one patient. The purpose of the study was to create an experimental model of MPMTs with one dominating tumor. Methods: The study included 21 female BALB/c Nude mice. The main group included mice with simultaneous subcutaneous inoculation of tumors: Guerin's carcinoma (0.5 million tumor cells in 0.5 ml of saline solution) under the right scapula and B16/F10 melanoma (0.5 ml of suspension diluted 1:20 in saline solution) under the left scapula. Control groups included females with melanoma or carcinoma inoculated at the same dosage and volume as in the main group. Results: In a MPMT model, tumors appeared 3 times faster than in controls and demonstrated larger volumes: melanoma – by 7.5 times, carcinoma – by 2.2 times; the survival of mice with MPMTs decreased. Carcinoma in a MPMT model metastasized to melanoma and almost completely suppressed its growth. Melanoma was represented by a small “island” of tumor tissue 3-4 mm in diameter and was located just under the skin at the site of injection of melanoma cells. The light part of the same loose pasty consistency as the dark part, with a diameter of 6-7 mm, was located around the dark “center” of melanoma. The rest part of the tumor located under the left scapula looked like an elongated grayish-pink node of a dense elastic consistency - just like the tumor located under the right scapula, which was much larger in volume. The right and left tumors did not merge with each other; there was a small distance of about 2-3 mm between them. A small lesion of caseous necrosis, 6–7 mm in diameter, was recorded in the center of the right tumor node of Guerin's carcinoma; there was no necrosis in the left tumor. Smaller size, the absence of necrosis and visually more “young” carcinoma tissue on the left indicated its later appearance than that on the right, which, in combination with the remnants of melanoma fused to the left tumor and the absence of “contact” between the left tumor and the right one, indicated the metastatic nature of Guerin’s carcinoma on the left. B16/F10 melanoma did not metastasize. Conclusions: In simultaneous subcutaneous inoculation of murine B16/F10 melanoma and rat Guerin’s carcinoma to female BALB/c Nude mice, carcinoma cells metastasized to melanoma and suppressed its growth.

Immunotherapy-induced antibodies to endogenous retroviral envelope glycoprotein confer tumor protection in mice

Following curative immunotherapy of B16F10 tumors, ~60% of mice develop a strong antibody response against cell-surface tumor antigens. Their antisera confer prophylactic protection against intravenous challenge with B16F10 cells, and also cross-react with syngeneic and allogeneic tumor cell lines MC38, EL.4, 4T1, and CT26. We identified the envelope glycoprotein (env) of a murine endogenous retrovirus (ERV) as the antigen accounting for the majority of this humoral response. A systemically administered anti-env monoclonal antibody cloned from such a response protects against tumor challenge, and prophylactic vaccination against the env protein protects a majority of naive mice from tumor establishment following subcutaneous inoculation with B16F10 cells. These results suggest the potential for effective prophylactic vaccination against analogous HERV-K env expressed in numerous human cancers.

Precision modeling of gall bladder cancer patients in mice based on orthotopic implantation of organoid-derived tumor buds

Genetically engineered mice (GEM) are the gold standard for cancer modeling. However, strict recapitulation of stepwise carcinogenesis from a single tumor-initiating epithelial cell among genetically intact cells in adults is not feasible with the currently available techniques using GEM. In previous studies, we partially overcame this challenge by physically isolating organs from adult animals, followed by genetic engineering in organoids and subcutaneous inoculation in nude mice. Despite the establishment of suitable ex vivo carcinogenesis models for diverse tissues, tumor development remained ectopic and occurred under immunodeficient conditions. Further refinement was, therefore, necessary to establish ideal models. Given the poor prognosis and few models owing to the lack of gall bladder (GB)-specific Cre strain, we assumed that the development of authentic models would considerably benefit GB cancer research. Here, we established a novel model using GB organoids with mutant Kras and Trp53 loss generated in vitro by lentiviral Cre transduction and CRISPR/Cas9 gene editing, respectively. Organoid-derived subcutaneous tumor fragments were sutured to the outer surface of the GB in syngeneic mice, which developed orthotopic tumors that resembled human GB cancer in histological and transcriptional features. This model revealed the infiltration of similar subsets of immune cells in both subcutaneous and orthotopic tumors, confirming the appropriate immune environment during carcinogenesis. In addition, we accurately validated the in vivo efficacy of gemcitabine, a common therapeutic agent for GB cancer, in large cohorts. Taken together, this model may serve as a promising avatar of patients with GB cancer in drug discovery and precision medicine.

Experimental Challenge of Sheep and Cattle with Dugbe Orthonairovirus, a Neglected African Arbovirus Distantly Related to CCHFV

Dugbe orthonairovirus (DUGV) is a tick-borne arbovirus within the order Bunyavirales. DUGV was first isolated in Nigeria, but virus isolations in ten further African countries indicate that DUGV is widespread throughout Africa. Humans can suffer from a mild febrile illness, hence, DUGV is classified as a biosafety level (BSL) 3 agent. In contrast, no disease has been described in animals, albeit serological evidence exists that ruminants are common hosts and may play an important role in the transmission cycle of this neglected arbovirus. In this study, young sheep and calves were experimentally inoculated with DUGV in order to determine their susceptibility and to study the course of infection. Moreover, potential antibody cross-reactivities in currently available diagnostic assays for Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) were assessed as DUGV is distantly related to CCHFV. Following subcutaneous inoculation, none of the animals developed clinical signs or viremia. However, all ruminants seroconverted, as demonstrated by two DUGV neutralization test formats (micro-virus neutralization test (mVNT), plaque reduction (PRNT)), by indirect immunofluorescence assays and in bovines by a newly developed DUGV recombinant N protein ELISA. Sera did not react in commercial CCHFV ELISAs, whereas cross-reactivities were observed by immunofluorescence and immunoblot assays.

Effects of Subcutaneous Ochratoxin-A Exposure on Immune System of Broiler Chicks

Ochratoxin A (OTA), an immunosuppressive mycotoxin, can increase the risk of many infectious diseases and contribute to economic losses to the poultry industry. The immunosuppressive effect has mainly been investigated through oral exposure; however, birds may also be contaminated through skin absorption. The present study investigated the influence of OTA exposure on the defense system of broiler chicks through the subcutaneous route and including low doses. Groups of broiler chicks (Cobb), 05 days old, were exposed to subcutaneous inoculation of OTA at concentrations of 0.1; 0.5; 0.9; 1.3; and 1.7 mg OTA/kg body weight. The size of the lymphoid organs, circulating immune cells, and total IgY and IgA levels were evaluated 21 days post inoculation. Subcutaneous OTA exposure decreased the weight of the thymus, spleen, and bursa of Fabricius, and leukocytopenia (p < 0.05) was detected in chicks of the OTA treated groups. In a dose-dependent way, decreased levels of circulating lymphocytes and heterophils (p < 0.05), and increased levels of monocytes (p < 0.05) were detected. Decreased IgY and IgA serum concentrations were noted in the OTA treated groups (p < 0.05). In conclusion, subcutaneous OTA exposure induces immunosuppression even at low levels.

Urine proteome changes in rats with approximately ten tumor cells subcutaneous inoculation

Biomarkers are changes associated with the disease. Without homeostatic control, urine accumulates very early changes and is an ideal biomarker source. Usually, we performed urinary biomarker studies involving at least thousands of tumor cells. But no tumor starts from a thousand tumor cells. Can we observe any urine proteome changes in rats with approximately ten tumor cells subcutaneous inoculation? Here, we serially diluted Walker-256 carcinosarcoma cells to a concentration of 102/mL and subcutaneously inoculated 0.1 mL of these cells into nine rats. Urine proteomes on days 0, 13 and 21 were profiled by LC-MS/MS analysis and studied with unsupervised clustering analysis. Samples at three time points were almost clustered together, indicating a good consistency in these nine rats. Differential proteins on days 13 and 21 were mainly associated with cell adhesion, autophagic cell death, changes in extracellular matrix organization, angiogenesis, and the pentose phosphate pathway. All of these enriched functional processes were reported to contribute to tumor progression and could not be enriched through random allocation analysis. Our results indicated that 1) the urine proteome reflects changes associated with cancer even with approximately ten tumor cells in the body and that 2) the urine proteome reflects pathophysiological changes in the body with extremely high sensitivity and provides potential for a very early screening process of clinical patients.

Identification of Austwickia chelonae as cause of cutaneous granuloma in endangered crocodile lizards using metataxonomics

The crocodile lizard (Shinisaurus crocodilurus Ahl, 1930) is an endangered reptile species, and in recent years many have died from diseases, especially the rescued and breeding individuals. However, pathogens underlying these diseases are unclear. In this study, we report our effort in rapidly identifying and isolating the pathogen that causes high mortality in crocodile lizards from Guangdong Luokeng Shinisaurus crocodilurus National Nature Reserve. The typical symptom is cutaneous granuloma in the infected crocodile lizards. Metagenomic next-generation sequencing (mNGS) is a comprehensive approach for sequence-based identification of pathogenic microbes. In this study, 16S rDNA based mNGS was used for rapid identification of pathogens, and microscopy and microbe isolation were used to confirm the results. Austwickia chelonae was identified to be the dominant pathogen in the granuloma using 16S rDNA based mNGS. Chinese skinks were used as an animal model to verify the pathogenicity of A. chelonae to fulfill Koch’s postulates. As expected, subcutaneous inoculation of A. chelonae induced granulomas in the healthy Chinese skinks and the A. chelonae was re-isolated from the induced granulomas. Therefore, A. chelonae was the primary pathogen that caused this high mortality disease, cutaneous granuloma, in crocodile lizards from Guangdong Luokeng Shinisaurus crocodilurus National Nature Reserve. Antibiotics analysis demonstrated that A. chelonae was sensitive to cephalothin, minocycline and ampicillin, but not to kanamycin, gentamicin, streptomycin and clarithromycin, suggesting a possible treatment for the infected crocodile lizards. However, surgical resection of the nodules as early as possible was recommended. This study is the first report of pathogenic analysis in crocodile lizards and provides a reference for disease control and conservations of the endangered crocodile lizards and other reptiles. In addition, this study indicated that mNGS of lesions could be used to detect the pathogens in animals with benefits in speed and convenient.