Human sarcomas contain RNA related to the RNA of a mouse leukemia virus

Soft tissue sarcoma of the pleural cavity

Seventeen cases of soft tissue sarcoma (STS) developing in the pleural cavity were collected from Japanese hospitals, and their clinical and pathologic findings summarized. Eight of the 17 patients had a 15-year to 50-year (mean, 28.8) history of chronic pleural inflammatory disease (pleuritis, pyothorax, and pulmonary tuberculosis) before the onset of the pleural sarcoma. Histologically, malignant fibrous histiocytoma was the most common tumor type (11 cases), followed by angiosarcoma (four). The age at diagnosis of the sarcoma ranged from 15 to 74 years (mean, 58); the male-to-female ratio was 3.3:1. In the eight cases of sarcoma associated with chronic pleural inflammatory disease, male preponderance was more marked (7:1). The commonest presenting symptom was chest pain. A mass could be detected by chest roentgenograms in 13 patients and computed tomographic scans in 15 patients. No patient had distant metastases at first admission. Thirteen patients were treated by surgery, chemotherapy, and/or radiation therapy. Thirteen of the 17 patients died 1 to 87 months (mean, 14.2) after therapy for STS. The actuarial 1-year survival rate was 38.5%. These findings suggest that long-standing pleural inflammation might be an etiologic factor for development of pleural STS.

Time course of C-type retrovirus expression in mice submitted to osteosarcomagenic doses of 224radium

Virus particles with the biochemical properties of C-type retroviruses appeared transiently in bone tissues of (C3H x 101) f1 hybrid mice early after treatment with 224 Radium; such particles were then again detected in the bones of the irradiated animals at the onset of osteosarcoma formation and in the osteosarcomas. Antibodies against a murine retrovirus isolated from a 224 Ra-induced osteosarcoma were produced and detected in the serum of the 224 Ra-treated animals within a month after treatment began. The antibody levels plateaued to a maximum after about 2 months and remained elevated until the tumors started to develop. The antibody concentration in the serum of these irradiated animals decreased then progressively to reach levels similar to those observed in untreated controls. It thus appears that the imminence of osteosarcoma development can be predicted by monitoring the anti-C-type virus antibody levels in the serum of the irradiated mice. These experiments also strongly suggest that treatment with 224Radium induces expression of endogenous viruses in the animals.

Purification and biochemical characterization of a virus-specific reverse transcriptase from human osteosarcoma tissue

A RNA-dependent DNA polymerase (RTase) was purified from human osteosarcoma tissue by successive column chromatography of the microsomal fraction on DEAE-cellulose (DE-23 and DE-52) and phosphocellulose. The purified enzyme has a molecular weight of about 68,000, a pH optimum of 8.1, a Mg2+ optimum of 0.8 mM, Mn2+ optimum of 1.0 mM and a KCl optimum of 60 mM. The enzyme transcribes (rA)n . (dT)12, (rC)n . (dG)12-18 and (2-O-methyl C)n . (dG)18, but is unable to transcribe (dA)n . (dT)10. The enzyme has no catalytic activity in the presence of oligodeoxynucleotide initiators alone, indicating the absence of terminal deoxynucleotidyl transferase. The purified enzyme is able to transcribe the heteropolymeric regions of a 70S RNA from R(Mu)LV. The presented data support the presence of a RNA-dependent DNA polymerase in human osteosarcoma tissue with biochemical properties, resembling those of C-type RNA tumor viruses.

Serological characterization of a purified reverse transcriptase from osteosarcoma of a child

Serological analysis of the reverse transcriptase (RTase), purified from human osteosarcoma tissue, has shown that it is antigenically related to DNA polymerases from BEV and from RD-114. No cross-reactivity of the osteosarcoma RTase was observed with RTases purified from AMV, RLV, SiSV, GaLV and from human spleen of a patient with myelofibrosis.

Particles from mouse melanoma B16 containing reverse transcriptase and 70S RNA related to human melanoma cytoplasmic RNA

The mouse melanoma B16 contains particles encapsulating high molecular weight RNA of 60--70S size associated with a reverse transcriptase. The [3H]DNA synthesized by these particles possesses homology with RNA isolated from a hamster melanoma and from three human malignant melanomas.

RNA-reverse transcriptase complex from cultured human myeloma-leukemia cells

A high molecular weight RNA-reverse transcriptase complex in the culture media of peripheral leukocytes obtained from two Japanese patients with myeloma-leukemia was detected by demonstration of a 3H-uridine peak and a peak of DNA polymerizing activity banding at a density of 1.15-1.19g/ml. The enzyme in the complex was able to utilize poly(rA)-d(pT)10 or poly (rC)-d(pG) 12-18, but not poly (dA)-d(pT) 10 or (dT) 12-18 as template-primers. The sucrose density sedimentation analysis revealed that RNA in the complex sedimented at a location of approximately 50s and 20-30s.

Biochemical evidence for viral-like characteristics in cerebrospinal fluids of brain tumor patients

Previous work done in this laboratory has shown that human Central Nervous System tumors possess attributes in common with those found in RNA tumor viruses. Because of the intimate physical relationship between the circulating cerebro-spinal fluid and the Central Nervous System, particles derived from tumors in this system may very well be shedded into the surrounding fluid system thus displaying similar biochemical attributes. Twenty samples of cerebro-spinal fluids were examined. Fifteen were from patients with various types of tumors in various location of the Central Nervous System. Five were from patients with unrelated diseases. Eleven or 74% of those from tumor patients were found to be positive when simultaneous detection assays were done on their core structures. None of the control was positive. The [3H]DNA synthesized from core structures hybridized readily to polysomal RNAs from a solid tumor. Particles from them were found to have a density of 1.867 g/ml sucrose gradient.

Proviral sequences of baboon endogenous type C RNA virus in DNA of human leukaemic tissues

Hybridisation of RNA from a baboon endogenous type C RNA virus to DNA from tissues of leukaemic patients indicates that a virus of this type is horizontally transmitted among humans. DNA from several patients with leukaemia hybridised 70% of the hybridisable RNA from baboon endogenous type C RNA virus (BaEV) and yielded hybrids of high tm, whereas DNA from normal human tissues hybridised only 23% of the BaEV RNA, and the tm of these hybrids was lower.

Oncornaviruslike particles in human malignancies

Mesenchymal and epithelial human malignancies were examined in the simultaneous detection test for the presence of particles with 70 S RNA and reverse transcriptase. Out of the 23 tumors tested 14 were found to be positive (61%). The finding that 2 uterine cancers contained 70 S RNA and reverse transcriptase indicates that uterine cancers may belong to the list of malignancies where the involvement of oncornaviruses is suspected. Out of the 10 human sarcomas examined in this study 4 were shown to contain particles with properties of oncornaviruses.

Evidence of particle-associated RNA-directed DNA polymerase and high molecular weight RNA in human gastrointestinal and lung malignancies

Previous communications have demonstrated that neoplastic cells of human breast cancers, leukemias, lymphomas, sarcomas, and brain tumors contain particles with similar diagnostic attributes as those found in RNA oncornaviruses. The present paper concerns malignancies of the gastrointestinal and pulmonary systems for which, like brain tumors, no suitable animal model or corresponding virus exists. By means of the simultaneous detection assay, these tumors have been found to contain 70S RNA and RNA-directed DNA polymerase encapsulated in particulate components possessing densities of 1.16-1.17 g/ml. Twelve out of 17 (70%) colon carcinomas, three out of five (60%) gastric carcinomas, all of three rectal carcinomas, and seven out of ten (70%) lung carcinomas contained detectable levels of these virus-like entities. None of the corresponding normal tissues was positive.

Specificity of the DNA product of RNA-dependent DNA polymerase in type C viruses. II. Quantitative analysis

A number of mammalian Type C viruses were analyzed for relatedness by the technique of DNA.RNA hybridization. Viral DNAs were prepared in single-stranded form from complexes with 70S viral RNA formed during endogenous polymerase reactions. Extent of hybridization was assayed with the single-strand nuclease (S-1) from Aspergillus oryzae. Results obtained indicated a high degree of viral specificity, with significant cross-reactions being observed only with viruses obtained from within a species, as in the case of mouse and cat viruses, or in the special case of woolly monkey-gibbon comparisons. Comparisons of RD-114 virus, recently determined to be of feline origin, and conventional feline Type C viruses (FeLV), revealed minimal relatedness, especially when feline virus was grown on human cells, thus indicating the possibility of coexistence of greatly disparate Type C viruses within one species. A rat-specific virus, recovered from tumors induced by murine sarcoma virus, was found to contain genetic material common to both the original mouse virus and viruses indigenous to the rat, even though only rat-specific proteins have been detected during infection by this virus.

Unique nuclear DNA sequences in the involved tissues of Hodgkin's and Burkitt's lymphomas

Previous studies have demonstrated that Hodgkin's, Burkitt's, and other human lymphomas contain particulate elements encapsulating 70S RNA and RNA-dependent DNA polymerase. [(3)H]DNA probes endogenously synthesized by these particles were used to demonstrate that the nuclear DNA of the lymphomas contain particle-related sequences that cannot be detected (less than 1/20th of a copy per genome) in the DNA of normal cells. This result agrees with our earlier findings in human leukemias. The data are inconsistent with any etiologic concept that invokes germ-line transmission of at least one complete copy of the particulate information associated with the malignancy. The unique sequences found in the nuclear DNA of Burkitt's and Hodgkin's tissues are related to each other but not to the DNA of the Epstein-Barr virus.

Strandedness and complementarity of DNA from long-term RNA-dependent DNA polymerase reactions of Soehner-Dmochowski murine sarcoma virus

The DNA product of the endogenously instructed RNA-dependent DNA polymerase reaction of murine sarcoma virus continued to be synthesized for as long as 64 h in the presence of 0.008% Triton X-100. Higher detergent concentrations and actinomycin D inhibited DNA product synthesis. The DNA product from long-term polymerase reactions consisted of small DNA fragments as shown by sedimentation in alkaline sucrose gradients. The enzymatic DNA product was separated into a slow sedimenting fraction and a fast sedimenting fraction by rate-zonal centrifugation. Fast sedimenting DNA was the predominant fraction made in viral polymerase reactions containing 262 mM NaCl. By using a combination of S-1 nuclease and pancreatic RNase A, the amount of single-stranded DNA, double-stranded DNA, and DNA-RNA hybrid present in the slow-sedimenting and fast-sedimenting fractions was determined. Under standard polymerase conditions of 70 mM NaCl, single-stranded DNA was the major form of DNA found in both fractions. In contrast, the prevalent form of DNA made in the presence of 262 mM NaCl was DNA-RNA hybrid. Hybridization studies in which either S-1 nuclease or pancreatic RNase A was used to measure hybrid formation demonstrated not only that the DNA product was complementary in base sequence to the RNA genome, but also that at least 79 to 84% of the RNA genome was transcribed into complementary DNA.

Biological and biochemical evidence for an interaction between Marek's disease herpesvirus and avian leukosis virus in vivo

The DNA-containing Epstein-Barr herpesvirus has been implicated in the etiology of Burkitt's lymphoma, a malignant tumor of children in Africa. Recently, however, particles possessing four biochemical characteristics of RNA tumor viruses have also been identified in these tumors. The fact that both types of viruses are found suggests that an interaction between them may be playing a role in the etiology of Burkitt's lymphoma. To explore this possibility with a defined animal model, experiments were performed with the avian Marek's disease, a malignant lymphoproliferative disease associated with a herpesvirus. Controlled contact studies demonstrated that tumorigenesis in a line of isolator-derived, barrier-sustained, specific pathogen-free chickens requires exposure to both the Marek's disease herpesvirus and an avian leukosis virus, Rous-associated virus, type 2. Exposure to either agent alone did not result in tumors. Molecular hybridization experiments to cytoplasmic RNA from similarly contact-exposed conventional Cornell S-line chickens provided further evidence for the occurrence of an interaction between Marek's disease herpesvirus and the avian leukosis virus.

In vitro production of mouse mammary tumor virus in a mouse mammary tumor ascites line

An ascites line derived from a spontaneous mouse mammary carcinoma produces, on explantation and cultivation in vitro, large amounts of oncornavirus particles. The biochemical, biophysical, and electron microscopic characteristics of the virions are described. Molecular hybridization and immunological methods identify these virions as mouse mammary tumor virus.

Particles with RNA of high molecular weight and RNA-directed DNA polymerase in human brain tumors

We have previously shown that neoplastic cells of human breast cancers, leukemias, lymphomas, and sarcomas contain particles similar to the viruses that have been established as etiologic agents of these diseases in mice. The present paper concerns tumors of the central nervous system for which no suitable animal model or corresponding virus exists. Nevertheless, using the simultaneous detection test, we showed that human brain tumors contain 70S RNA and RNA-directed DNA polymerase encapsulated in a particulate component possessing a density of 1.17 g/ml. These particles satisfy the three diagnostic criteria that characterize RNA tumor viruses of animals. 24 Out of 26 (92%) of the most malignant (glioblastoma and medulloblastoma) brain tumors examined contained these virus-like entities.

Leukemia-specific DNA sequences in leukocytes of the leukemic member of identical twins

The discovery in human leukemic cells of particulate elements encapsulating 70S RNA and RNA-directed DNA polymerase made possible the synthesis of a [(3)H]DNA probe that could detect leukemia-specific sequences in the DNA of normal and leukemic individuals. In an earlier study of a series of unrelated leukemic patients, we established that the nuclear DNA of their leukemic cells contain particle-related sequences that cannot be detected in leukocytes of normal individuals. This result is inconsistent with the virogene concept that demands the inclusion of one complete copy of oncogenic information in the genome of every normal cell. The present study carries this analysis one step further by showing, with two sets of identical twins, that the leukemic member contains particle-related sequences in the DNA of his leukocytes that cannot be detected in the leukocytes of his healthy identical sibling. This finding implies that the additional leukemia-specific information found in the DNA of the leukemic individuals must have been inserted subsequent to fertilization. This outcome argues against the virogene hypothesis or any other etiologic concept that invokes vertical transmission through the germ line of the particle-related information found uniquely in the DNA of leukemic cells.

Determination of natural host taxonomy of RNA tumor viruses by molecular hybridization: application to RD-114, a candidate human virus

The lysogenic bacteriophages and the RNA tumor viruses have in common the ability to add their genetic information to the genome of their host cells. The biological similarity extends further; data summarized here indicate that they both possess homology to the DNA of their uninfected indigenous hosts. Sharing of common sequences with normal host DNA has been established with avian, murine, feline, and primate oncornaviruses. This finding provides a method for determining the taxonomic position of the natural host of any new RNA tumor virus isolated. Application of this approach to RD-114 revealed extensive hybridization to normal cat DNA and little, if any, hybridization to human DNA. We conclude that the data assign a feline origin rather than a human origin to RD-114.

Burkitt's tumors contain particles encapsulating RNA-instructed DNA polymerase and high molecular weight virus-related RNA

Burkitt's lymphomas, linked by previous studies with the DNA-containing Epstein-Barr virus, contain an RNA related in sequence to that of Rauscher leukemia virus. The present study establishes that the viral-related RNA found in Burkitt's tumors is a 70S component encapsulated with RNA-instructed DNA polymerase in a particle possessing a density characteristic of RNA tumor viruses. Further, the DNA synthesized by the Burkitt particles hybridizes specifically to the RNA of Rauscher leukemia virus. Thus, four features characteristic of a known oncogenic RNA agent are also exhibited by particles found with a high (87%) frequency in Burkitt's tumors. The relation between the RNA particle and the Epstein-Barr virus and their etiological roles remains to be elucidated. However, relevant to these issues is the finding reported here that the presence of Epstein-Barr virus information in nonneoplastic cells does not lead to the production of the RNA particles that have been detected now in three different human neoplasias, including leukemias, breast cancer, and Burkitt's disease.

RNA related to that of a murine leukemia virus in Burkitt's tumors and nasopharyngeal carcinomas

RNA homologous to that of the Rauscher leukemia virus has been detected in Burkitt's lymphomas and nasopharyngeal carcinomas. Earlier excellent experimental evidence has linked these two human tumors with the Epstein-Barr virus, a DNA-containing agent.

Nuclear DNA sequences present in human leukemic cells and absent in normal leukocytes

The central purpose of the present study was to test the proposition that the nuclear DNA of every human cell contains whatever information is necessary and sufficient for transformation to malignancy. The experiments were made possible by our earlier identification in human leukemic cells of particulate elements encapsulating 70S RNA and RNA-directed DNA polymerase. The [(3)H]DNA synthesized by these particles was used as a probe, through molecular hybridization, to normal and leukemic DNA. The results obtained establish that leukemic nuclear DNA contains particle-related sequences that cannot be detected in normal leukocytes. This outcome does not support the virogene-oncogene theory, which postulates the inclusion of at least one complete copy of oncogenic information in the genome of every normal cell. The data suggest that we may not be forced to cope with an omnipresent DNA segment coding for malignancy. Under the circumstances, we can perhaps entertain more hopeful pathways leading to the control and cure of cancer.