Adiponectin Deficiency Suppresses Rhabdomyosarcoma Associated with Gut Microbiota Regulation.

The gut microbiota is very important in the initiation, progression, and dissemination of cancer, and the regulation of microbiota has been employed as a novel strategy to enhance the effect of immunotherapy. Adiponectin (APN), an adipocyte-derived hormone, plays a vital role in regulating the immune response of innate immune cells. The deficiency of APN inhibits rhabdomyosarcoma growth. However, whether this function is associated with regulating gut microbiota remains unknown. To investigate, we performed 16S ribosomal RNA (rRNA) gene sequencing on the fecal microbiome of APN gene knockout mice to determine whether APN deletion affects the gut microbiota. We found APN deficiency alters gut microbial functions involved in metabolism, genetic information processing, and cellular processes. In addition, a decreased abundance of Bacteroides and an increased abundance of Prevotella and Helicobacter were observed in rhabdomyosarcoma-bearing APN knockout mice; these bacteria were associated with the inhibition of rhabdomyosarcoma growth. These findings suggest that gut microbiota may be a potential target of APN deficiency against rhabdomyosarcoma.

Activation of viruses in human tumors by 5-iododeoxyuridine and dimethyl sulfoxide.

Dimethyl sulfoxide added to cultures first treated with 5-iododeoxyuridine increased C-type virus production approximately tenfold in a human rhabdomyosarcoma cell line. 5-Iododeoxyuridine followed by dimethyl sulfoxide also activated a similar C-type virus in a metastatic tumor from a bronchial node taken from a 52-year-old male.

Reverse transcriptases of primate viruses as immunological markers.

Antibodies were prepared against the DNA polymerases (reverse transcriptases) of three potentially oncogenic RNA viruses of primates. Two type C viruses, isolated from a woolly monkey fibrosarcoma and from a gibbon ape lymphosarcoma, have polymerases that are immunologically related to each other and are distinct from the type C viruses isolated from other mammals.

Clostridium spores as anti-tumour agents.

The successful treatment of cancer remains a huge challenge. Consequently, efforts are being made to develop alternative methods of tumour therapy. One of these is the use of live Clostridium species, based on the observation that obligatory anaerobic bacteria specifically colonize the hypoxic and necrotic regions that are present in solid tumours but normally absent in other parts of the body. Although past results have fuelled scepticism about its clinical use, recent promising findings emphasize the potential of Clostridium-directed tumour therapy. These recent developments are reviewed and the reintroduction of this tumour-targeting protein delivery system into clinical settings is discussed.

Transformation of human embryo cells with the use of cell-free extracts of a human rhabdomyosarcoma cell line (HUS-2): brief communication.

Cell-free extracts of the human rhabdomyosarcoma cell line HUS-2 caused the transformation of human embryo fibroblasts. This transformation included morphologic alteration, karyotypic change, and an increase in culture longevity. With the use of sex markers, multiple karyotypes confirmed that the human embryo fibroblasts were transformed, and the use of cell-free material further suggested the presence of a transforming virus. RNA-dependent DNA polymerase activity in a particle with a specific gravity of 1.16 g/cm3 indicated the presence of an RNA type C virus. Evidence also suggested that the known mammalian type C viruses, routine cytopathic effect-inducing viruses, or mycoplasma were not the agents responsible for the transformation. That both the donor (HUS-2) and converted (HUE-T) cell lines cross-reacted with antisera prepared against HUE-T indicated a common antigen arising in the process of conversion of HUS-2 cells to HUE-T cells.

Studies on a transplantable murine rhabdomyosarcoma.

Well-differentiated rhabdomyosarcomas developed in 8 of 10 BALB/c mice inoculated with cell-free extracts of two lesions arising in bats previously inoculated with the Moloney strain of murine sarcoma virus. The tumors could be transplanted in BALB/c mice and other strains of mice compatible at the H-2 locus. A tumorigenic clonal cell culture line (R2) was established from a transplanted tumor. Ultrastructural studies of the primary and transplanted tumors and R2 cells revealed thick and thin myofilaments characteristic of myoblasts. These cells contained numerous cisternal type-A virus-like particles, but no type-C particles were found. Attempts to recover, rescue, or chemically induce transforming or nontransforming viruses from transplantable tumors and the R2 cell line were unsuccessful. The tumor cells lacked the murine type-C virus gs antigen. Hybridization data confirmed the apparent lack of viral RNA in the tumor cells.

Autogenous immunity to endogenous RNA tumor virus: reactivity of natural immune sera to antigenic determinants of several biologically distinct murine leukemia viruses.

Sera from normal (C57BL/6XC3H/Anf)F1(B6C3F1) mice reacted with several biologically distinct murine leukemia virus(es) (MuLV) by radioimmune precipitation assays with the use of purified tritiated leucine-labeled virus. The reactivities of this natural antibody to viral envelope antigens of two laboratory strains (Rauscher and Moloney) and two endogenous mouse C-type viruses (AKR and BALB:virus-2) were further analyzed and compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Similar patterns of antibody reactivities to AKR MuLV and the two member viruses of the Friend-Moloney-Rauscher group were found. Three major antigenic determinants of the virus envelope, gp71, gp43, and p15, were recognized by and precipitated natural antibody. In all viruses examined, normal B6C3F1 sera precipitated comparable amounts of gp71 and gp43. However, compared with the other viruses, the amount of p15 (relative to the glycoproteins) precipitating from BALB:virus-2 was significantly lower. This appears to be due to a lesser amount of p15 on the xenotropic virus. While heterologous antisera to purified gp71 and p15 of MuLV reacted to a certain degree with rhabdomyosarcoma virus 114 and rat leukemia virus, natural mouse antibody did not. These results suggest that MuLV have common antigenic determinants recognized by natural antibody, and that the reactivities of natural antibody in an autogenous immune response are restrictive in contrast to immune antibody produced in a heterologous host.

Mapping of the RD phenotype of the Nancy strain of coxsackievirus B3.

The RD variants of group B coxsackieviruses differ from their parental strains in having the ability to replicate in a human rhabdomyosarcoma cell line, RD. The nucleotide sequence of the P1 region of the RD variant of coxsackievirus B3 strain Nancy (CB3NRD) was determined by sequencing cloned cDNAs, obtained by PCR amplification. A comparison between the established nucleotide sequence and that of the P1 region from the parental virus revealed 12 point mutations which corresponded to six amino acid replacements. To identify if the P1 region is responsible for the phenotype of CB3NRD, a chimeric virus was constructed, using an infectious cDNA clone of CB3. The P1 region of the infectious cDNA was replaced by cDNA fragments from CB3N (parental strain Nancy) or CB3NRD and the resulting recombinants were assayed for their ability to infect and replicate in RD cells. The results showed that the RD phenotype of CB3NRD maps in the P1 region. Furthermore, a chimera which only contained the 5' part of the P1 region derived from CB3NRD and the remaining P1 sequence from CB3N was able to replicate in RD cells, suggesting that the VP2 polypeptide contains at least one determinant for the RD phenotype.

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.

Search for proviral simian sarcoma associated virus sequences in bone marrow cells from children with neoplasms of mesenchymal origin.

DNAs obtained from bone marrow cells of 31 children with neoplasms of mesenchymal origin were tested for the presence of proviral simian sarcoma associated virus by southern blot-hybridization. The lower limit of detection in this method was one provirus per 20-30 cells. Applying stringent conditions of hybridization, no proviral DNA could be detected in any of the samples tested, most of which were from children with leukemia or with bone marrow invading lymphosarcomas. Relaxed conditions of hybridization revealed a diffuse pattern of hybridizing fragments which was similar in all DNAs tested, including normal human DNA.

Tumor promoter-stimulated synthesis of Mason-:Pfizer monkey virus.

The tumor promoter 12-0-tetradecanoyl-phorbol-14-acetate (TPA) increases by severalfold the synthesis of Mason-Pfizer monkey virus (MPMV), a type D retrovirus, when the virus is growing in human embryo kidney (HEK) cells. The effect is transient and paralleled by a striking morphological alteration of the cells. The optimal TPA concentration for stimulation is 5 ng. ml-1. Contrary to infected HEK cells, TPA induces at similar concentrations neither stimulation of MPMV synthesis nor altered morphology in persistently MPMV-infected cells of the continuous human tumor cell line A 204.

Improvement of Clostridium tumour targeting vectors evaluated in rat rhabdomyosarcomas.

Previous studies have demonstrated the feasibility of using apathogenic clostridia as a promising strategy for hypoxia-specific tumour targeting. The present study shows that the use of the vascular targeting compound combretastatin A-4 phosphate could significantly (P<0.001) increase the number of Clostridium vegetative cells in rat rhabdomyosarcomas with sizes between 0.2 cm(2) and 3 cm(2). Furthermore, this study showed that administration of metronidazole for a 9-day period was sufficient to eliminate systemically administered Clostridium from the tumour. Moreover, previous Clostridium spore administration did not effect tumour colonisation, regardless of the immune response status of the host.

Optimization of tumor-targeted gene delivery by engineered attenuated Salmonella typhimurium.

BACKGROUND: Attenuated Salmonella typhimurium has been demonstrated as a potential gene delivery vector. Previous findings induce the necessity to optimize tumor selectivity and bacterial dosing in relation to tumor volume and intratumoral therapeutic gene expression. MATERIALS AND METHODS: Attenuated Salmonella VNP20009 and VNP20047 (expressing cytosine deaminase) were systemically administered to tumor-bearing rats. The bacteria were quantified in tumor and normal organs. Conversion of 5-fluorocytosine to 5-fluorouracil was evaluated using thin layer chromatography. RESULTS: Tumor colonization efficiency was dependent on Salmonella density, administration route and tumor volume. Colonization of normal tissues gradually decreased with time, while intratumoral proliferation of bacteria remained high during the follow-up period. The Optimal Therapeutic Dose (OTD) was found to be 5.10(7) cfu/rat. Intratumoral VNP20047-expressed CDase leading to the conversion of 5-FC to 5-FU was detected in vivo. CONCLUSION: Our results indicate the need to define an OTD, probably for each species, when using genetically engineered Salmonella as a tumor- and species-selective vector in cancer therapy.

[Reproduction of leukovirus RD-114 in diploid and heteroploid human cells]. / Reproduktsiia leikovirusa RD-114 v diploidnykh i geteroploidnykh kletkakh cheloveka

The capacity of leukovirus RD-114 to replicate in human embryo lung diploid cell cultures and continuous human angiosarcoma cell cultures (AS and 709 lines). Differences in the capacity to support the virus reproduction were observed in the two strains of human embryo lung cells (HEL-1 and HEL-3) and the two continuous angiosarcoma cell lines. No virus reporduction was observed in mouse and rat cell cultures. No cytopathic or transformation changes were caused by the virus in any of the systems examined.