Viral-related RNA in Hodgkins' disease and other human lymphomas

The mechanism of interferon effect on cell transformation by murine sarcoma virus

Mouse interferon (IFN) was found to inhibit murine sarcoma virus (MSV)-induced neoplastic transformation of normal rat kidney (NRK) cells. This effect was observed upon examining the formation of foci of morphologically altered cells and colonies of anchorage-independent cells. IFN had no cytotoxic effect on MSV-transformed NRK cells, nor on their focus or colony-forming ability. It was therefore apparent that its inhibitory effect was directed against the viral role in cell transformation. In attempts to define the mechanism of this effect, we found that IFN delayed the initiation of the cytoplasmic viral DNA synthesis. However, the amount of this DNA eventually formed in IFN-treated cells was the same as in the control cells. Furthermore, the transport of this DNA to the nucleus was slower in IFN-treated cells, although all of it was finally transferred. However, while most of the viral DNA integrated into the genome of the control cells, very little integration occurred in IFN-treated cells. The unintegrated viral DNA of these cells was slowly degraded. Therefore, if the cells recovered from the antiviral effect of IFN when intact viral DNA molecules still existed in their nucleus, they could resume viral DNA integration and cell transformation. IFN was found to block viral DNA supercoiling. Since supercoiled viral DNA is considered to be a precursor to integrated provirus, it seems that the inhibition of both integration and cell transformation is due to this impaired coiling.

Effect of mouse interferon on cell transformation and virus production in rat cells exogenously infected with moloney murine sarcoma and leukemia viruses

Foci of transformed cells, produced by MSV(124), appeared to result only from the primary infection, since this virus stock yielded a virus-nonproducing infection. On the other hand, the majority of foci scored in MSV/MLV-infected cultures, were generated by multiple secondary infections with the progenies of the primary infection. Mouse interferon (IF) was highly inhibitory for cell transformation by both virus stocks. However, this inhibition was apparent in MSV(124) infected cultures only if IF was added at least 12 h before infection, whereas in MSV/MLV-infected cultures IF was highly effective even if added 24 h after infection. The inhibition of focus formation by MSV(124) was irreversible after removal of IF, suggesting that IF inhibited an early step before provirus integration into the host genome. By contrast, in MSV/MLV-infected cultures focus formation was almost completely restored after recovery from the IF effect. Nevertheless, examination of virus production after IF removal proved that in MSV/MLV infection, too IF exerted and inhibitory effect before provirus integration.

Molecular evidence of viral-like biochemical activities in human genitourinary malignancies

We have demonstrated previously that core structures of urine samples from patients with genitourinary malignancies contain ribonucleic acid-directed deoxyribonucleic acid polymerase and a high molecular weight ribonucleic acid. If these particles originated from the existing genitourinary malignancies then the malignancies should contain similar characteristics. We examined 13 prostatic carcinomas, 4 bladder carcinomas, 1 urethral carcinoma and 1 hypernephroma. Positive reactions were noted in 10 of the 13 prostatic carcinomas (77 per cent), all 4 bladder carcinomas, the 1 urethral carcinoma and the hypernephroma with the simultaneous detection assay. The control samples consisted of 7 tissues of benign prostatic hypertrophy, and tissue from 2 normal bladders and 1 normal kidney. None of these tissues showed a positive response. Tritium labeled deoxyribonucleic acid probes synthesized from the malignant tissues hybridized to the polysomal ribonucleic acids but not to the corresponding normal tissues. Particles derived from the probes have a density of 1,1620 in sucrose gradient. No sequence homology could be demonstrated with various known oncogenic ribonucleic acid viruses nor with malignancies arising from other organs.

Search for viral nucleic sequences in rheumatoid cells

DNA and RNA were extracted from synovial membranes, synovial fibroblast cells, peripheral blood lymphocytes, and synovial fibroblast cells strains derived from patients with rheumatoid arthritis and other joint conditions. They were hybridised after immobilisation on nitrocellulose filters with iodinated viral nucleic acids extracted from measles, rubella virus, SV--40, and a retrovirus, RD--114. In addition, in situ-hybridisation was carried out on sections of synovial membranes by means of iodinated measles and rubella virus RNA. In no case did any hybridisation occur. Positive control systems included synovial fibroblast strains transformed with SV--40, LLC--MK2 cells chronically infected with rubella virus and RD cells infected with RD--114. It was concluded tht the synovial cells did not contain viral genomes of measles, rubella virus, SV--40, or RD--114, or at least at a level equivalent to the positive control cells.

Viruses and human cancer

The etiologic role of viruses in a great variety of animal tumors has been demonstrated beyond doubt. There is, however, no firm evidence that any malignant disease of man is caused by viruses. Data accumulated on the association of viruses with human cancer are reviewed.

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.

Search for infective mammalian type-C virus-related genes in the DNA of human sarcomas and leukemias

DNA was extracted from two human sarcoma cell lines, TE-32 and TE-418, and the leukemic cells from five children with acute myelocytic leukemia, three children with acute lymphocytic leukemia and four adults with acute myelocytic leukemia. The DNAs, assayed for infectivity by transfection techniques, induced no measurable virus by methods which would detect known mammalian C-type antigens or RNA-directed DNA polymerase in TE-32, D-17 dog cells and other indicator cells, nor did they recombine with or rescue endogenous human or exogenous murine or baboon type-C virus. Model systems used as controls were human sarcoma cells, TE-32 and HT-1080, and human lymphoma cells TE-543, experimentally infected with KiMuLV, GaLV or baboon type-C virus, all of which released infectious virus and whose DNAs were infectious for TE-32 and D-17 dog cells. Other model systems included two baboon placentas and one embryonic cell strain spontaneously releasing infectious endogenous baboon virus and yielding DNAs infectious for D-17 dog cells but not for TE-32 cells. Four other baboon embryonic tissues and two embryonic cell strains, releasing either low levels of virus or no virus, did not yield infectious DNA.

Detection of viral-like cores from the urine of patients with genito-urinary malignancies

Simultaneous detection assays on the core structures derived from the cerebrospinal fluid samples of patients with various types of central nervous system tumors have demonstrated the feasibility of this technique in detecting some of the diagnostic features of RNA tumor viruses. Similar assays done on urine samples from patients iwth various types of tumors in their genitourinary tracts have shown that of the 18 such samples from tumor patients, 15 or 83% were found to be positive. The control samples consisted of three from patients with benign prostatic hypertrophy and four from normal persons. None of these gave a positive reaction. [3H]DNA probes synthesized from the core structures from them hybridized readily to their corresponding polysomal RNAs but no to control tissues. The densities of particles from these samples have been found to be 1.168 g/ml for bladder carcinoma and 1.165 for prostatic carcinoma, the same densities as those found RNA tumor viruses.

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.

Simultaneous detection of reverse transcriptase and high molecular weight RNA in tissue of patients with Hodgkin's disease and patients with leukemia

Complexes of high-molecular-weight RNA and reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) have been detected in 14(77.8%) of 18 spleen from patients with Hodgkin's disease and in all samples tested of peripheral leukocytes and spleens from leukemic patients. The enzyme and its template are localized in a particle having a density between 1.16 and 1.19 g/ml. These observations describe characteristic features of RNA tumor viruses.

Biochemical and electron microscopical evidence for the presence of oncorna viruses in spleen tissue from two patients with haematological malignancies

In extracts of spleen tissue from two patients with haemotological malignancies an RNA dependent DNA polymerase was found in particles with a density of 1.16, that is at the density of oncorna viruses. After treatment with noniomic detergents the enzyme activity was found in particles with a density of 1.23-1.24, similar to the density of oncorna viral cores. A simultaneous detection test with this core fraction material for 70 S RNA and RNA dependent DNA polymerase was positive for both patients. Electron microscopical inspection of the material with a density of 1.16 revealed immature C-type virus like particles, various stages of maturing particles and a number of particles resembling mature C-type oncorna viruses. In two normal spleens from patients with carcinoma of the colon and oesophagus respectively and in three spleens from patients with no history of malignancy no RNA dependent DNA polymerase was found. Material from one normal spleen was examined in the electron microscope and no virus-like particles were seen.

Molecular evidence for a viral etiology of human CNS tumors

The newer methods of molecular virology, including molecular hybridization and the "simultaneous detection test," were used to examine human brain tumors for evidence of RNA tumor viruses. It was found that they contained 70S RNA and RNA-directed DNA polymerase, both encapsulated in a particle possessing a density of 1.17 g/ml. These particles therefore satisfy the three diagnostic features that characterize the animal RNA tumor viruses. Of 26 of the most malignant (glioblastoma and medullo blastoma) brain tumors examined, 24 (92%) contained these virus-like entities. The possible usefulness of these particles as aids in diagnosis and monitoring therapy is briefly discussed.

Bovine leukemia virus: an exogenous RNA oncogenic virus?

Short term cultures of bovine leukemic lymphocytes release virus particles with biochemical properties of RNA oncogenic viruses. These particles, tentatively called Bovine Leukemia Virus (BLV) have a high molecular weight-reverse transcriptase complex and a density averaging 1.155 g/ml in sucrose solutions. Molecular hybridizations between BLV-3H cDNA and several viral RNAs show that BLV is not related to Mason-Pfizer Monkey Virus (MPMV) Simian Sarcoma Associated Virus (SSV-1) Feline Leukemia Virus (FeLV) or Avian Myeloblastosis Virus (AMV). Rauscher Leukemia Virus (RLV) exhibits a slight but reproducible relatednesse to BLV. The high preference of BLV reverse transcriptase for Mg++ as the divalent cation suggests that BLV might be an atypical mammalian leukemogenic type C virus. Hybridization studies using BLV 3H cDNA as a probe suggest that the DNA of bovine leukemic cells contains viral sequences that cannot be detected in normal bovine DNA.

Oncornavirus-like particles released from arginine-deprived human lymphoblastoid cell lines

Type-C RNA tumor virus particles were released from three different human lymphoblastoid cell lines after incubation in arginine-deficient medium. The released virus-like particles were characterized by (a) their ability to band in sucrose gradients at a density of 1.16-1.18 g/ml; (b) the presence of an RNA-directed DNA polymerase activity resembling that of the oncornaviruses; and (c) isolation of cores that band at a density of 1.26-1.27 g/ml in sucrose gradients. Examination of the arginine-deprived human lymphoblastoid cell line strain P3HR-1 by electron microscopy revealed the presence of C-type particles in the intracellular spaces.

Oncornavirus-like particles in human skin cancers

A high-molecular-weight RNA encapsulated with an RNA-instructed DNA polymerase in particles possessing the density characteristic of the RNA tumor viruses has been detected in 13 out of 14 human malignant melanomas. The [3H]DNA synthesized by these particles in an endogenous reaction hybridizes to RNA extracted from the human melanoma particulate structures, but not to RNA from normal skin. Similar particles containing RNA and enzyme have been found in basal cell and squamous cell carcinomas of the skin. The RNA of the melanoma particles is easily distinguishable by hybridization from the RNAs found in the particles of the basal and squamous cell carcinomas.

Transformation of cultured human embryonic fibroblasts by oncornavirus-like particles released from a human carcinoma cell line

A fibroblast-like cell culture was established from a stomach biopsy of a patient with metastatic adenocarcinoma. One of the cultures, at the 6th passage level, left unattended for a month at 37 degrees, produced numerous foci of epithelioid cells. Upon subculturing, an epithelioid cell line, designated HCCL (human carcinoma cell line), was established. The HCCL cells released particles possessing the characteristics of oncornaviruses: density 1.175 g/ml, cores with a density of 1.22-1.26 g/ml, high-molecular-weight RNA (60-70S) and RNA-instructed DNA polymerase activity (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7). Inoculation of particles released from HCCL cells into cultures of human embryo muscle fibroblasts resulted in the appearance of foci of transformed cells.

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.

An antigen in Hodgkin's disease tissue cultures: radioiodine-labeled antibody studies

An antiserum was prepared in rabbits against an antigen obtained by density gradient sedimentation of centrifuged medium from monolayer cultures of spleens involved by Hodgkin's disease. The antiserum was tested by isotopic antibody techniques with cells from each of eight cultures derived from spleens involved by Hodgkin's disease, four cultures derived from normal adult spleen, and one culture each of fetal spleen and thymus. By an indirect radioiodine-labeled antibody assay, anti-Hodgkin's disease globulin reacted with an antigen on the surface of cells from the Hodgkin's disease cultures, the quantity of which was related to the number of target cells and the amount of antibody used. This Hodgkin's disease tissue-culture antigen did not react with a rabbit antiserum against fractionated medium from a normal spleen culture, nor against noncultured Hodgkin's disease tumor tissue. The tumor specificity of the Hodgkin's disease tissue-culture antigen was assessed by a direct technique using (125)I-labeled anti-Hodgkin's disease globulin absorbed with either cultured Hodgkin's disease cells or with cultured normal cells. By this method the quantity of antigen on cells from Hodgkin's disease cultures was 15- to 30-fold greater than that on cells from normal cultures. The Hodgkin's disease tissue-culture antigen is intimately associated with the propagation of the tumor in monolayer cultures, but its identity has not been established: it could be a viral component, a tumor or fetal antigen, or a normal tissue constituent.

Antibodies to Epstein-Barr and other viruses in children with acute lymphoblastic leukaemia

Sixty-eight children with acute lymphoblastic leukaemia were tested for antibodies to Epstein-Barr (EB) virus and to other viruses. The antibody response to the test viruses in these children was unremarkable, with the exception of EB virus, where the presence of complement-fixing antibodies in children tested during the first month of their illness suggested that a higher proportion had previous experience with this virus than was the case in control children. The implications of this observation with regard to leukaemogenesis are discussed.

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.