Features of the interaction of antitumor mitoxantrone compounds with sarcoma 45 tumor DNA]

The interaction of antitumoral drug mitoxantrone with DNA of the tumor sarcoma 45 and healthy animals liver has been investigated according to the character of changes on the absorption spectra at binding at 30 degrees C and 0.11 M NaCl. The investigation shows that the interaction of mitoxantrone with DNA of sarcoma 45 differs from that with DNA of healthy animals liver. The calculations show that the saturation stoichiometry by both DNA is one mitoxantrone molecule per 2.5 base pairs with the binding constant k = 4 x 10(5) M-1 (for binding mitoxantrone with liver DNA) and k = 3 x 10(6) M-1 (with tumor DNA). Possible reason of such a difference is discussed on the basis of structural peculiarities of tumor DNA.     

The influence of low-energy millimeter electromagnetic waves on the stability of DNA molecules in solution

The influence of low-energy millimeter electromagnetic waves on aqueous saline solution of DNA from the liver of healthy rats and rats with sarcoma 45 has been investigated. The characteristic parameters of irradiated and unirradiated DNA, melting temperature, and the range of melting were obtained from melting curves. The duration of exposure did not practically affect the range of melting, while the thermostability of DNA increased; as irradiation duration increased to 90 min, the melting temperature of tumor increased by approximately 1.5 degrees C. It was assumped that the increase in the thermostability of DNA is due to a more effective stabilization of the DNA double helix caused by the dehydration of Na(+)- ions present in the solution.     

A case of interdigitating dendritic cell sarcoma studied by whole-exome sequencing

Interdigitating dendritic cell sarcoma (IDCS) is an aggressive neoplasm and is an extremely rare disease, with a challenging diagnosis. Etiology of IDCS is also unknown and most studies with only case reports. In our case, immunohistochemistry showed that the tumor cells were positive for S100, CD45, and CD68, but negative for CD1a and CD21. This study aimed to investigate the causative factors of IDCS by sequencing the protein-coding regions of IDCS. We performed whole-exome sequencing with genomic DNA from blood and sarcoma tissue of the IDCS patient using the Illumina Hiseq 2500 platform. After that, we conducted Sanger sequencing for validation of sarcoma-specific variants and gene ontology analysis using DAVID bioinformatics resources. Through comparing sequencing data of sarcoma with normal blood, we obtained 15 nonsynonymous single nucleotide polymorphisms (SNPs) as sarcoma-specific variants. Although the 15 SNPs were not validated by Sanger sequencing due to tumor heterogeneity and low sensitivity of Sanger sequencing, we examined the function of the genes in which each SNP is located. Based on previous studies and gene ontology database, we found that POLQ encoding DNA polymerase theta enzyme and FNIP1 encoding tumor suppressor folliculin-interacting protein might have contributed to the IDCS. Our study provides potential causative genetic factors of IDCS and plays a role in advancing the understanding of IDCS pathogenesis.     

Protein synthesizing cell apparatus in malignant growth and pharmacotherapy by chlofiden

Data on the influence of a new antitumor preparation chlofiden on the general contents of rat liver ribosomes and sarcoma 45 and their division on free and membrane of membrane bound and decrease of free ribosomes during tumor growth supposed synthesis of specific proteins bound are given in the paper. It was shown that in the liver of tumor bearing rats total and membrane bound ribosomes decreased and the level of free ribosomes increased. High contents of free ribosomes in sarcoma 45 may testify increase of intracellular protein synthesis including processes of cell growth and division as well as the tendency for increase. Chlofiden normalized total contents, increased free and decreased liver membrane bound ribosomes contents, during tumor growth supposed synthesis of specific proteins. Increase of free ribosomes and decrease of their specific radioactivity in sarcoma 45 testified membrane damage by chlofiden and inhibition of intracellular protein synthesis which are essential in cell division.     

Analysis of DNA distribution in Kaposi's sarcoma in patients with and without the acquired immune deficiency syndrome

While Kaposi's sarcoma in patients with the acquired immune deficiency syndrome (AIDS) may present as a multicentric disease with progressive organ involvement, the classic form of Kaposi's sarcoma is an indolent tumor seldom affecting extracutaneous areas and almost never responsible for the patient's demise. An attempt was made to correlate these clinical differences with the nuclear DNA content of tumor cells in histologic sections from 15 patients (9 with AIDS and 6 without AIDS). All tumors showed a similar DNA distribution pattern, with most cells appearing diploid, indicative of a low malignant potential. These findings indicate that Kaposi's sarcoma of both AIDS and non-AIDS patients is a tumor of intrinsically low malignancy and that lack of immune surveillance is most probably responsible for its aggressive biologic behavior in many AIDS patients.     

Effect of low-energy microwaves on DNA stability in solution

DNA isolated from liver of healthy and tumor-bearing (sarcoma 45) rats was irradiated in water-salt solution with weak microwaves (64.5 GHz, 50 μW/cm²). The heat stability of DNA increased with irradiation time (a raise of 1.5°C in T _m for “tumor” DNA after 90 min, without changes in ΔT), which may be associated with dehydration of the surrounding Na⁺ ions.     

Neutral cytoplasmatic deoxyribonuclease of the rat liver and spleen in carcinogenesis

The activity of cytoplasmic neutral DNA in the liver and spleen of albino rats is studied when the tumour process develops after fast neutrons irradiation, when tumour is induced by 3,4-benzpyrene and after sarcoma 45 transplantation. It is shown that an increase in the enzymic activity with a further decrease during the process development is observed for all studied types of carcinogenesis in the pretumour period. Changes in the activity of natural inhibitor and the enzyme form bound with the inhibitor were not found (except for one or another index in the spleen of animals with sarcoma 45). The enzyme activation in the pretumour period is considered as a tumour defence response of the organism aimed at elimination of damages in DNA which arise as a result of direct or indirect action of carcinogen.     

Rat sequences of the Kirsten and Harvey murine sarcoma virus genomes: nature, origin, and expression in rat tumor RNA.

Two murine sarcoma viruses, the Kirsten and the Harvey, were isolated by passage of mouse type C leukemia viruses through rats. These sarcoma viruses have genomes containing portions of their parental type C mouse leukemia virus genomes, in stable association with specific rat cellular sequences that we find to be quite likely not those of a rat type C leukemia virus. To determine if these murine sarcoma viruses provide a model relevant to the events occurring in spontaneous tumors, we have hybridized DNA and RNA prepared from rat tumors and normal rat tissues to [3H]DNA prepared from the Kirsten murine sarcoma virus. We have also hybridized these rat tissue nucleic acids to [3H]DNA prepared from a respresentative endogenous rat type C leukemia virus, the WFU (Wistar-Furth). Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected in the DNA of both tumor and normal tissues, with no evidence of either gene amplification or additional sequences being present in tumor DNA. Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected at elevated concentrations in the RNA of many rat tumors and in specific groups of normal tissues.     

Viral oncogene-induced DNA damage response is activated in Kaposi sarcoma tumorigenesis

Kaposi sarcoma is a tumor consisting of Kaposi sarcoma herpesvirus (KSHV)-infected tumor cells that express endothelial cell (EC) markers and viral genes like v-cyclin, vFLIP, and LANA. Despite a strong link between KSHV infection and certain neoplasms, de novo virus infection of human primary cells does not readily lead to cellular transformation. We have studied the consequences of expression of v-cyclin in primary and immortalized human dermal microvascular ECs. We show that v-cyclin, which is a homolog of cellular D-type cyclins, induces replicative stress in ECs, which leads to senescence and activation of the DNA damage response. We find that antiproliferative checkpoints are activated upon KSHV infection of ECs, and in early-stage but not late-stage lesions of clinical Kaposi sarcoma specimens. These are some of the first results suggesting that DNA damage checkpoint response also functions as an anticancer barrier in virally induced cancers.     

THE IN VIVO REUTILIZATION OF LYMPHOCYTIC AND SARCOMA DNA BY CELLS GROWING IN THE PERITONEAL CAVITY

An ascites tumor, Sarcoma I, was transplanted to isologous and homologous mice which had been labeled with tritiated thymidine from 1 to 24 hours previously. Radioautographic preparations revealed labeled host lymphocytes emerging to mingle with the transplanted tumor and the subsequent appearance of nuclear radioactivity in the sarcoma. Sarcoma cells cultured subcutaneously or in Millipore diffusion chambers in previously labeled mice did not demonstrate significant radioactivity. Transplantation of washed, H³-thymidine-labeled lymphocytes to non-radioactive, sarcoma-bearing mice was followed by the gradual appearance of nuclear radioactivity in the sarcoma. The label in the sarcoma was entirely removed by deoxyribonuclease but not by ribonuclease treatment prior to radioautography. Intraperitoneal injections of purified, H³-thymidine-labeled sarcoma or lymphoid DNA in normal or tumor-bearing mice were followed by radioactivity appearing in sarcoma or normal peritoneal mononuclear cells. It was concluded that reutilization of DNA and its metabolites may occur in vivo, and the conditions under which reutilization may be detected are discussed.     

Bone marrow subsets differentiate into endothelial cells and pericytes contributing to Ewing's tumor vessels

Hematopoietic progenitor cells arising from bone marrow (BM) are known to contribute to the formation and expansion of tumor vasculature. However, whether different subsets of these cells have different roles in this process is unclear. To investigate the roles of BM-derived progenitor cell subpopulations in the formation of tumor vasculature in a Ewing's sarcoma model, we used a functional assay based on endothelial cell and pericyte differentiation in vivo. Fluorescence-activated cell sorting of human cord blood/BM or mouse BM from green fluorescent protein transgenic mice was used to isolate human CD34+/CD38(-), CD34+/CD45+, and CD34(-)/CD45+ cells and mouse Sca1+/Gr1+, Sca1(-)/Gr1+, VEGFR1+, and VEGFR2+ cells. Each of these progenitor subpopulations was separately injected intravenously into nude mice bearing Ewing's sarcoma tumors. Tumors were resected 1 week later and analyzed using immunohistochemistry and confocal microscopy for the presence of migrated progenitor cells expressing endothelial, pericyte, or inflammatory cell surface markers. We showed two distinct patterns of stem cell infiltration. Human CD34+/CD45+ and CD34+/CD38(-) and murine VEGFR2+ and Sca1+/Gr1+ cells migrated to Ewing's tumors, colocalized with the tumor vascular network, and differentiated into cells expressing either endothelial markers (mouse CD31 or human vascular endothelial cadherin) or the pericyte markers desmin and alpha-smooth muscle actin. By contrast, human CD34(-)/CD45+ and mouse Sca1(-)/Gr1+ cells migrated predominantly to sites outside of the tumor vasculature and differentiated into monocytes/macrophages expressing F4/80 or CD14. Our data indicate that only specific BM stem/progenitor subpopulations participate in Ewing's sarcoma tumor vasculogenesis.     

Preparation of tissues for DNA flow cytometric analysis

A method for measuring DNA in tissue cells by flow cytometry utilizing a one step combination nuclear isolation-DNA fluorochrome staining procedure is described. A variety of cells and tissues, both in vivo and in vitro, was used to illustrate the universal nature of this technique. These included murine bone marrow, liver testicle, sarcoma brain tumor, rat pancreatic islets, human peripheral blood, colon mucosa, colon cancer, sarcoma and brain tumor tissues. A special nuclear isolation medium, which contained either of the DNA fluorochromes, 4',6-diamidino-2 phenylindole-2 HCl or propidium iodide, was utilized successfully to isolate single suspensions of DNA fluorochrome stained nuclei in a rapid (5-10 min), consistent manner from a variety of tissues and cells. Multiple sampling of the same tissue or comparison between whole tissues and their single cell isolates showed that a representative sample was being obtained.     

人疱疹病毒8型KS330基因片段的检出与Kaposi肉瘤的关系

HHV-8 sequences were recently identified in 100% of the amplifiable samples from AIDS patients with Kaposi's sarcoma(KS)and in 15% of the non-KS tissue samples from AIDS patients, so there is a strong correlation of Kaposi's sarcoma with HHV-8. Serum and DNA samples from a clinically diagnosed Kaposi's sarcoma Chinese patient were tested. HHV-8 antibody was tested positive by IFA and HIV-I antibody was negative by Western blot. The KS330 PCR product was found both in peripheral blood mononuclear cells and in KS tumor cells from this Chinese patient. This supports the hypothesis that Kaposi's sarcoma results from infection of HHV-8.     

Detection of circulating tumor-derived material in peripheral blood of pediatric sarcoma patients: A systematic review

BackgroundDetection of circulating tumor-derived material (cTM) in the peripheral blood (PB) of cancer patients has been shown to be useful in early diagnosis, prediction of prognosis, and disease monitoring. However, it has not yet been thoroughly evaluated for pediatric sarcoma patients.MethodsWe searched the PubMed and EMBASE databases for studies reporting the detection of circulating tumor cells, circulating tumor DNA, and circulating RNA in PB of pediatric sarcoma patients. Data on performance in identifying cTM and its applicability in diagnosis, and evaluation of tumor characteristics, prognostic factors, and treatment response was extracted from publications.ResultsA total of 79 studies were assigned for the present systematic review, including detection of circulating tumor cells (116 patients), circulating tumor DNA (716 patients), and circulating RNA (2887 patients). Circulating tumor cells were detected in 76% of patients. Circulating DNA was detected in 63% by targeted NGS, 66% by shallow WGS, and 79% by digital droplet PCR. Circulating RNA was detected in 37% of patients.ConclusionOf the cTM from Ewing's sarcoma and rhabdomyosarcoma ctDNA proved to be the best target for clinical application including diagnosis, tumor characterization, prognosis, and monitoring of disease progression and treatment response. For osteosarcoma the most promising targets are copy number alterations or patient specific micro RNAs, however, further investigations are needed to obtain consensus on clinical utility.     

Radioprotective action of a GGS-10 gaseous hypoxic mixture on the DNA supramolecular complex of normal tissues and sarcoma 45 of rats

Gas hypoxic mixture (GHM-10) inhaled by rats during gamma-irradiation (2 to 20 Gy) effectively protects the supramolecular complex of DNA (SC DNA) in bone marrow and spleen, but fails to protect this complex in sarcoma 45. GHM-10 itself has been shown to induce rapid and prolonged, but irreversible, decrease in SC DNA elastic viscosity in normal tissues.     

Combinations of PARP Inhibitors with Temozolomide Drive PARP1 Trapping and Apoptosis in Ewing’s Sarcoma

Ewing’s sarcoma is a malignant pediatric bone tumor with a poor prognosis for patients with metastatic or recurrent disease. Ewing’s sarcoma cells are acutely hypersensitive to poly (ADP-ribose) polymerase (PARP) inhibition and this is being evaluated in clinical trials, although the mechanism of hypersensitivity has not been directly addressed. PARP inhibitors have efficacy in tumors with BRCA1/2 mutations, which confer deficiency in DNA double-strand break (DSB) repair by homologous recombination (HR). This drives dependence on PARP1/2 due to their function in DNA single-strand break (SSB) repair. PARP inhibitors are also cytotoxic through inhibiting PARP1/2 auto-PARylation, blocking PARP1/2 release from substrate DNA. Here, we show that PARP inhibitor sensitivity in Ewing’s sarcoma cells is not through an apparent defect in DNA repair by HR, but through hypersensitivity to trapped PARP1-DNA complexes. This drives accumulation of DNA damage during replication, ultimately leading to apoptosis. We also show that the activity of PARP inhibitors is potentiated by temozolomide in Ewing’s sarcoma cells and is associated with enhanced trapping of PARP1-DNA complexes. Furthermore, through mining of large-scale drug sensitivity datasets, we identify a subset of glioma, neuroblastoma and melanoma cell lines as hypersensitive to the combination of temozolomide and PARP inhibition, potentially identifying new avenues for therapeutic intervention. These data provide insights into the anti-cancer activity of PARP inhibitors with implications for the design of treatment for Ewing’s sarcoma patients with PARP inhibitors.     

RNA complementary to the genome of RNA tumor viruses in virions and virus-producing cells.

Cells producing type C (avain sarcoma virus) or type B (mouse mammary tumor virus) RNA tumor viruses contain small amounts of RNA complementary to the viral genomes. The negative strands are complementary to at least 30 to 45% of the viral genomes and are found as RNA-RNA duplexes in the nucleus and cytoplasm of infected cells and in mature virions.     

The effect of x-ray radiation and hypoxia on the proteolytic activity of the normal rat spleen and during tumor growth

The influence of X-radiation on activity of lysosomal enzymes (D, L, H cathepsins) in rat spleen tissue and in inoculated rat sarcoma 45 has been investigated. Intact rats and rats with tumors were subjected to whole-body and sarcoma 45 to local irradiation with doses of 0.155 C/kg and 0.31 C/kg in conditions of breathing gas hypoxic mixture containing 90% of nitrogen and 10% of oxygen (GHM-10). The combined exposure to radiation and GHM-10 was shown to produce a certain protective action (e.g. normalized cathepsin activity) in the spleen. In the tumor tissue the protective effect of GHM-10 was absent.