Kaposi's sarcoma herpesvirus is associated with osteosarcoma in Xinjiang populations.

Osteosarcoma is the most common malignant tumor of bone predominately affecting adolescents and young adults. Based on animal studies, a viral etiology of osteosarcoma was proposed more than a half-century ago, but no viral association with human osteosarcoma has been found. The Uyghur ethnic population in Xinjiang, China, has an unusually high prevalence of Kaposi's sarcoma-associated herpesvirus (KSHV) infection and elevated incidence of osteosarcoma. In the current study, we explored the possible association of KSHV infection and osteosarcoma occurrence. Our seroepidemiological study revealed that KSHV prevalence was significantly elevated in Uyghur osteosarcoma patients versus the general Uyghur population (OR, 10.23; 95%CI, 4.25, 18.89). The KSHV DNA genome and viral latent nuclear antigen LANA were detected in most osteosarcoma tumor cells. Gene expression profiling analysis showed that KSHV-positive osteosarcoma represents a distinct subtype of osteosarcomas with viral gene-activated signaling pathways important for osteosarcoma development. We conclude that KSHV infection is a risk factor for osteosarcoma, and KSHV is associated with some osteosarcomas, representing a newly identified viral-associated endemic cancer.

Activity of CK2α protein kinase is required for efficient replication of some HPV types.

Inhibition of human papillomavirus (HPV) replication is a promising therapeutic approach for intervening with HPV-related pathologies. Primary targets for interference are two viral proteins, E1 and E2, which are required for HPV replication. Both E1 and E2 are phosphoproteins; thus, the protein kinases that phosphorylate them might represent secondary targets to achieve inhibition of HPV replication. In the present study, we show that CX4945, an ATP-competitive small molecule inhibitor of casein kinase 2 (CK2) catalytic activity, suppresses replication of different HPV types, including novel HPV5NLuc, HPV11NLuc and HPV18NLuc marker genomes, but enhances the replication of HPV16 and HPV31. We further corroborate our findings using short interfering RNA (siRNA)-mediated knockdown of CK2 α and α' subunits in U2OS and CIN612 cells; we show that while both subunits are expressed in these cell lines, CK2α is required for HPV replication, but CK2α' is not. Furthermore, we demonstrate that CK2α acts in a kinase activity-dependent manner and regulates the stability and nuclear retention of endogenous E1 proteins of HPV11 and HPV18. This unique feature of CK2α makes it an attractive target for developing antiviral agents.

ZAP's stress granule localization is correlated with its antiviral activity and induced by virus replication.

Cellular antiviral programs encode molecules capable of targeting multiple steps in the virus lifecycle. Zinc-finger antiviral protein (ZAP) is a central and general regulator of antiviral activity that targets pathogen mRNA stability and translation. ZAP is diffusely cytoplasmic, but upon infection ZAP is targeted to particular cytoplasmic structures, termed stress granules (SGs). However, it remains unclear if ZAP's antiviral activity correlates with SG localization, and what molecular cues are required to induce this localization event. Here, we use Sindbis virus (SINV) as a model infection and find that ZAP's localization to SGs can be transient. Sometimes no apparent viral infection follows ZAP SG localization but ZAP SG localization always precedes accumulation of SINV non-structural protein, suggesting virus replication processes trigger SG formation and ZAP recruitment. Data from single-molecule RNA FISH corroborates this finding as the majority of cells with ZAP localization in SGs contain low levels of viral RNA. Furthermore, ZAP recruitment to SGs occurred in ZAP-expressing cells when co-cultured with cells replicating full-length SINV, but not when co-cultured with cells replicating a SINV replicon. ZAP recruitment to SGs is functionally important as a panel of alanine ZAP mutants indicate that the anti-SINV activity is correlated with ZAP's ability to localize to SGs. As ZAP is a central component of the cellular antiviral programs, these data provide further evidence that SGs are an important cytoplasmic antiviral hub. These findings provide insight into how antiviral components are regulated upon virus infection to inhibit virus spread.

Indirect Effects of COVID on Oncology Patients.

The interaction of coronavirus disease-2019 (COVID-19) and chemotherapy may result in worse outcomes. However, there may be more indirect effects of COVID. We report 3 cases in which treatment was delayed because of COVID-related inability or reluctance to travel. Oncology programs should consider such indirect effects when devising treatments.

Respiratory Failure in a Child With Pulmonary Metastatic Osteosarcoma and COVID-19.

The novel coronavirus, SARS-CoV-2, causes much more severe disease in adults than in children. Although it is anticipated that immune compromised children and children with cancer may be at higher risk of developing severe or fatal COVID-19, there are no currently published reports of fatal disease in a child with cancer. Because of the discrepancy in disease severity between adult and pediatric patients, we report the case of an adolescent with pulmonary metastatic osteosarcoma who died of COVID-19 early in the course of the pandemic in New York City in the hope that heightening awareness that pulmonary metastatic disease may predispose to a more severe outcome will increase surveillance in this vulnerable population.

Polyostotic osteosarcoma associated with avian leukosis virus infection in a captive bare-faced curassow (Crax fasciolata).

BACKGROUND: Osteosarcoma is a malignant mesenchymal bone tumor. Although it is a common tumor in the appendicular skeleton of dogs and cats, it is rarely reported in birds. Retroviruses are usually associated with solid tumor development in different avian species. CASE PRESENTATION: This report aims to describe a case of osteosarcoma associated with the avian leukosis virus in a captive bare-faced curassow (Crax fasciolata). A captive adult female bare-faced curassow presented with lameness, hyporexia, and a non-ulcerative and firm tumor in the right femur. The bird was euthanized due to the poor prognosis. Histopathology revealed an infiltrative mesenchymal neoplasm consisting of spindle cells with moderate cell pleomorphism, organized in bundles and interspersed by marked deposition of the osteoid matrix, which was compatible with osteosarcoma affecting both femur and tibiotarsus, with renal metastasis. Immunohistochemistry of the primary and metastatic tumor demonstrated vimentin expression by neoplastic cells. Samples of the neoplasm, bone marrow, and spleen were processed for PCR, which enabled the demonstration of proviral avian leukosis virus (ALV) DNA. CONCLUSIONS: To the best of our knowledge, this is the first report of an osteosarcoma in a bare-faced curassow with an unusual polyostotic manifestation and associated with ALV infection.

Cellular Zinc Finger Protein 622 Hinders Human Adenovirus Lytic Growth and Limits Binding of the Viral pVII Protein to Virus DNA.

Human adenovirus (HAdV) encodes a multifunctional DNA-binding protein pVII, which is involved in virus DNA packaging and extracellular immune signaling regulation. Although the pVII is an essential viral protein, its exact role in the virus life cycle and interplay with cellular proteins have remained to a large extent unclear. We have recently identified the cellular zinc finger protein 622 (ZNF622) as a potential pVII-interacting protein. In this study, we describe the functional consequences of the ZNF622-pVII interplay and the role of ZNF622 in the HAdV life cycle. ZNF622 protein expression increased, and it accumulated similarly to the pVII protein in the nuclei of virus-infected cells. The lack of the ZNF622 protein specifically increased pVII binding to viral DNA in the infected cells and elevated the pVII protein levels in the purified virions. In addition, ZNF622 knockout cells showed an increased cell lysis and enhanced accumulation of the infectious virus particles. Protein interaction studies revealed that ZNF622 forms a trimeric complex with the pVII protein and the cellular histone chaperon protein nucleophosmin 1 (NPM1). The integrity of this complex is important since ZNF622 mutations and NPM1 deficiency changed pVII ability to bind viral DNA. Collectively, our results implicate that ZNF622 may act as a cellular antiviral protein hindering lytic HAdV growth and limiting pVII protein binding to viral DNA.IMPORTANCE Human adenoviruses (HAdVs) are common human pathogens causing a wide range of acute infections. To counteract viral pathogenicity, cells encode a variety of antiviral proteins and noncoding RNAs to block virus growth. In this study, we show that the cellular zinc finger protein 622 (ZNF622) interacts with an essential HAdV protein known as pVII. This mutual interaction limits pVII binding to viral DNA. Further, ZNF622 has a role in HAdV life cycle since the lack of ZNF622 correlates with increased lysis of the infected cells and accumulation of the infectious virions. Together, our study reveals a novel cellular antiviral protein ZNF622, which may impede lytic HAdV growth.

Co-expression of Epstein-Barr virus-encoded RNA1 and viral latent membrane protein 1 in osteosarcoma: A novel insight of predictive markers.

Epstein-Barr virus is an etiologic agent of several malignancies. In this study, we explored the association of Epstein-Barr virus-encoded RNA1 and Epstein-Barr virus latent membrane protein 1 co-expression with osteosarcoma. Epstein-Barr virus-encoded RNA1 expression in tumor cells was quantified using reverse transcriptase polymerase chain reaction and in situ hybridization and Epstein-Barr virus latent membrane protein 1 expression was measured using immunohistochemistry staining. There was a statistically significant association between Epstein-Barr virus latent membrane protein 1 and Epstein-Barr virus-encoded RNA1 co-expression and characteristics of osteosarcoma such as nodal stage (p < 0.04), metastasis (p < 0.04), Ki67 index (p < 0.03), and tumor stage (p < 0.05). Co-expression of Epstein-Barr virus-encoded RNA1 and Epstein-Barr virus latent membrane protein 1 in tumors correlated with advanced osteosarcoma and indicated the aggressiveness of bone sarcoma.

Inactivated Sendai virus strain Tianjin induces apoptosis and autophagy through reactive oxygen species production in osteosarcoma MG-63 cells.

Sendai virus strain Tianjin, a novel genotype of Sendai virus, has been proven to possess potent antitumor effect on certain cancer cell types although inactivated by ultraviolet (UV). This study was carried out to investigate the in vitro anticancer properties of UV-inactivated Sendai virus strain Tianjin (UV-Tianjin) on human osteosarcoma cells and the underlying molecular mechanism. Our studies demonstrated UV-Tianjin significantly inhibited the viability of human osteosarcoma cell lines and triggered apoptosis through activation of both extrinsic and intrinsic pathways in MG-63 cells. Meanwhile, autophagy occurred in UV-Tianjin-treated cells. Blockade of autophagy with 3-methyladenine remarkably attenuated the inhibition of cell proliferation by UV-Tianjin, suggesting that UV-Tianjin-induced autophagy may be contributing to cell death. Furthermore, UV-Tianjin induced reactive oxygen species (ROS) production, which was involved in the execution of MG-63 cell apoptosis and autophagy, as evidenced by the result that treatment of N-acetyl-L-cysteine, a ROS scavenger, attenuated both apoptosis and autophagy. In addition, inhibition of apoptosis promoted autophagy, whereas suppression of autophagy attenuated apoptosis. Our results suggest that UV-Tianjin triggers apoptosis and autophagic cell death via generation of the ROS in MG-63 cells, which might provide important insights into the effectiveness of novel strategies for osteosarcoma therapy.

Anticancer effect of inactivated Sendai virus strain Tianjin on human osteosarcoma HOS cells.

Ultraviolet-inactivated Sendai virus strain Tianjin (UV-Tianjin) has been proved to have antitumor effects in many kinds of tumor cells. Here, we investigated the anticancer properties of UV-Tianjin on human osteosarcoma HOS cells and the underlying molecular mechanism. Apoptosis, intracellular reactive oxygen species (ROS) levels and mitochondrial membrane potential were determined by flow cytometry analysis. The expression levels of apoptosis-related proteins were tested by western blotting. The results showed that UV-Tianjin concentration-dependently induced apoptosis in HOS cells. UV-Tianjin-induced apoptosis was mediated by the mitochondrial pathway, which was confirmed by mitochondrial dysfunction, downregulation of B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-xL (Bcl-xL) and myeloid cell leukemia-1 (Mcl-1), upregulation of B-cell lymphoma 2 associated X protein (Bax) and Bcl-2 Homologous Antagonist/Killer (Bak), as well as the cleavage of caspase-9 and -3. Further analysis showed that UV-Tianjin augmented the phosphorylation of c-Jun N-terminal kinase, the extracellular-regulated kinase and p38, the major components of mitogen-activated protein kinase (MAPK) pathways, as well as the generation of ROS. Moreover, UV-Tianjin-induced apoptosis was remarkably attenuated by MAPK inhibitors and ROS inhibitor. Taken together, our results indicated that UV-Tianjin exerts antitumor effects by inducing mitochondria-dependent apoptosis involving ROS generation and MAPK pathway in human osteosarcoma HOS cells.

Impaired STING Pathway in Human Osteosarcoma U2OS Cells Contributes to the Growth of ICP0-Null Mutant Herpes Simplex Virus.

Human herpes simplex virus 1 (HSV-1) is a widespread pathogen, with 80% of the population being latently infected. To successfully evade the host, the virus has evolved strategies to counteract antiviral responses, including the gene-silencing and innate immunity machineries. The immediately early protein of the virus, infected cell protein 0 (ICP0), plays a central role in these processes. ICP0 blocks innate immunity, and one mechanism is by degrading hostile factors with its intrinsic E3 ligase activity. ICP0 also functions as a promiscuous transactivator, and it blocks repressor complexes to enable viral gene transcription. For these reasons, the growth of a ΔICP0 virus is impaired in most cells, except cells of the human osteosarcoma cell line U2OS, and it is only partially impaired in cells of the human osteosarcoma cell line Saos-2. We found that the two human osteosarcoma cell lines that supported the growth of the ΔICP0 virus failed to activate innate immune responses upon treatment with 2'3'-cyclic GAMP (2'3'-cGAMP), the natural agonist of STING (i.e., stimulator of interferon genes) or after infection with the ΔICP0 mutant virus. Innate immune responses were restored in these cells by transient expression of the STING protein but not after overexpression of interferon-inducible protein 16 (IFI16). Restoration of STING expression resulted in suppression of ΔICP0 virus gene expression and a decrease in viral yields. Overexpression of IFI16 also suppressed ΔICP0 virus gene expression, albeit to a lesser extent than STING. These data suggest that the susceptibility of U2OS and Saos-2 cells to the ΔICP0 HSV-1 is in part due to an impaired STING pathway.IMPORTANCE The DNA sensor STING plays pivotal role in controlling HSV-1 infection both in cell culture and in mice. The HSV-1 genome encodes numerous proteins that are dedicated to combat host antiviral responses. The immediate early protein of the virus ICP0 plays major role in this process as it targets hostile host proteins for degradation with its E3 ligase activity, and it disrupts repressor complexes via protein-protein interaction to enable viral gene transcription. Therefore, the ΔICP0 HSV-1 virus is defective for growth in most cells, except the human osteosarcoma cell lines U2OS and Saos-2. We found that both cell lines that support ΔICP0 virus infection have defects in the STING DNA-sensing pathway, which partially accounts for the rescue of the ΔICP0 virus growth. Restoration of STING expression in these cells rescued innate immunity and suppressed ΔICP0 virus infection. This study underscores the importance of STING in the control of HSV-1.

Antitumor effect of the Newcastle disease viral hemagglutinin-neuraminidase gene is expressed through an oncolytic adenovirus effect in osteosarcoma cells.

Newcastle disease virus (NDV) can specifically kill cancer cells and has less toxicity to normal cells. The hemagglutinin-neuraminidase (HN) protein is an important structural protein in NDV pathogenesis and has been postulated as a promising candidate for antitumor therapy. The aim of this study was to investigate the anticancer potential of recombinant adenovirus Ad-HN-PEG3p-E1a. An MTS assay was performed to determine viral proliferation after viral infection, the data showed that the proliferation ability of osteosarcoma cells decreased, whereas there was no significant change in normal hepatic cells. DAPI and Annexin V experiments showed that osteosarcoma cells were killed because of apoptosis, active oxygen content, and augmented mitochondrial membrane potential loss. Caspase Activity Assay Kits were used to detect the caspase-3 activities of the treated OS-732 for increased expression. Western blot analysis showed that cytochrome C increased significantly and apoptosis of the virus was confirmed in tumor cells. In-vivo experiments show that NDV has an inhibitory effect on tumor growth. The recombinant adenovirus, which is composed of a HN protein and progressive increment promoter PEG3p, could inhibit the growth of OS-732 and promote the apoptosis of tumor cells. However, there was no clear relationship with normal cell (L02) apoptosis.

Oncolytic Maraba Virus MG1 as a Treatment for Sarcoma.

The poor prognosis of patients with advanced bone and soft-tissue sarcoma has not changed in the past several decades, highlighting the necessity for new therapeutic approaches. Immunotherapies, including oncolytic viral (OV) therapy, have shown great promise in a number of clinical trials for a variety of tumor types. However, the effective application of OV in treating sarcoma still remains to be demonstrated. Although few pre-clinical studies using distinct OVs have been performed and demonstrated therapeutic benefit in sarcoma models, a side-by-side comparison of clinically relevant OV platforms has not been performed. Four clinically relevant OV platforms (Reovirus, Vaccinia virus, Herpes-simplex virus and Rhabdovirus) were screened for their ability to infect and kill human and canine sarcoma cell lines in vitro, and human sarcoma specimens ex vivo. In vivo treatment efficacy was tested in a murine model. The rhabdovirus MG1 demonstrated the highest potency in vitro. Ex vivo, MG1 productively infected more than 80% of human sarcoma tissues tested, and treatment in vivo led to a significant increase in long-lasting cures in sarcoma-bearing mice. Importantly, MG1 treatment induced the generation of memory immune response that provided protection against a subsequent tumor challenge. This study opens the door for the use of MG1-based oncolytic immunotherapy strategies as treatment for sarcoma or as a component of a combined therapy.

Kaposi's sarcoma herpesvirus microRNAs induce metabolic transformation of infected cells.

Altered cell metabolism is inherently connected with pathological conditions including cancer and viral infections. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS). KS tumour cells display features of lymphatic endothelial differentiation and in their vast majority are latently infected with KSHV, while a small number are lytically infected, producing virions. Latently infected cells express only a subset of viral genes, mainly located within the latency-associated region, among them 12 microRNAs. Notably, the metabolic properties of KSHV-infected cells closely resemble the metabolic hallmarks of cancer cells. However, how and why KSHV alters host cell metabolism remains poorly understood. Here, we investigated the effect of KSHV infection on the metabolic profile of primary dermal microvascular lymphatic endothelial cells (LEC) and the functional relevance of this effect. We found that the KSHV microRNAs within the oncogenic cluster collaborate to decrease mitochondria biogenesis and to induce aerobic glycolysis in infected cells. KSHV microRNAs expression decreases oxygen consumption, increase lactate secretion and glucose uptake, stabilize HIF1α and decreases mitochondria copy number. Importantly this metabolic shift is important for latency maintenance and provides a growth advantage. Mechanistically we show that KSHV alters host cell energy metabolism through microRNA-mediated down regulation of EGLN2 and HSPA9. Our data suggest that the KSHV microRNAs induce a metabolic transformation by concurrent regulation of two independent pathways; transcriptional reprograming via HIF1 activation and reduction of mitochondria biogenesis through down regulation of the mitochondrial import machinery. These findings implicate viral microRNAs in the regulation of the cellular metabolism and highlight new potential avenues to inhibit viral latency.

SAFETY AND TOXICITY OF AN ACCELERATED COARSELY FRACTIONATED RADIATION PROTOCOL FOR TREATMENT OF APPENDICULAR OSTEOSARCOMA IN 14 DOGS: 10 GY × 2 FRACTIONS.

Coarsely fractionated radiation is commonly used as a method for pain control in dogs with appendicular osteosarcoma, however there is little published information on optimal protocols. The aim of this retrospective, descriptive study was to report safety and toxicity findings in a sample of dogs with appendicular osteosarcoma that had been treated with a radiation scheme of 10 Gy delivered over two consecutive days for a total of 20 Gy. Dogs were included in the study if they had osteosarcoma that was treated with the aforementioned protocol. Dogs were excluded if treated with the same protocol for any other bone tumor besides osteosarcoma or inadequate follow-up. Thirteen of the 14 patients received adjuvant therapy with pamidronate and a nonsteroidal anti-inflammatory. Nine dogs received adjuvant chemotherapy with carboplatin after radiation was complete. Within a median of 14 days, 92.8% of dogs subjectively had improved pain control. Median duration of response (DOR) was 80 days (range 20-365). The majority of patients developed VRTOG grade one toxicity, primarily alopecia. Five dogs (35.7%) developed pathologic fracture postradiation treatment. Timing of fracture was variable ranging from 24 to 250 days. This radiation protocol was well tolerated, with minimal toxicity, subjectively improved survival time, and had the benefit of being completed in two consecutive days.

Proteomic analysis of the herpes simplex virus 1 virion protein 16 transactivator protein in infected cells.

The herpes simplex virus 1 virion protein 16 (VP16) tegument protein forms a transactivation complex with the cellular proteins host cell factor 1 (HCF-1) and octamer-binding transcription factor 1 (Oct-1) upon entry into the host cell. VP16 has also been shown to interact with a number of virion tegument proteins and viral glycoprotein H to promote viral assembly, but no comprehensive study of the VP16 proteome has been performed at early times postinfection. We therefore performed a proteomic analysis of VP16-interacting proteins at 3 h postinfection. We confirmed the interaction of VP16 with HCF-1 and a large number of cellular Mediator complex proteins, but most surprisingly, we found that the major viral protein associating with VP16 is the infected cell protein 4 (ICP4) immediate-early (IE) transactivator protein. These results raise the potential for a new function for VP16 in associating with the IE ICP4 and playing a role in transactivation of early and late gene expression, in addition to its well-documented function in transactivation of IE gene expression.

Significant association between human osteosarcoma and simian virus 40.

BACKGROUND: Simian virus 40 (SV40) has been considered to be an oncogenic viral agent in the development of osteosarcoma (OS), which to the authors' knowledge continues to be of unknown etiology. METHODS: In the current study, serum samples from patients with OS were investigated with an indirect enzyme-linked immunoadsorbent assay (ELISA) to test for the presence of immunoglobulin G antibodies, which react with SV40 antigens. In ELISA, SV40 antigens were represented by 2 synthetic polypeptides that mimic epitopes of the viral capsid proteins 1 to 3. Additional sera from patients with breast cancer and undifferentiated nasopharyngeal carcinoma as well as healthy subjects were the controls. RESULTS: Immunologic results suggested that antibodies that react with SV40 mimotopes were more prevalent (44%) in serum samples from patients with OS compared with healthy subjects (17%). The difference in prevalence between these cohorts was statistically significant (P<.001). It is interesting to note that in the patients with OS, significance indicated the difference between OS versus breast cancer (44% vs 15%; P<.001) and OS versus undifferentiated nasopharyngeal carcinoma (44% vs 25%; P<.05). CONCLUSIONS: The data from the current study indicate an association between OS and SV40. These data could be transferred to clinical applications for innovative therapies to address SV40-positive OS.

Recombination-dependent oligomerization of human papillomavirus genomes upon transient DNA replication.

We describe the extensive and progressive oligomerization of human papillomavirus (HPV) genomes after transfection into the U2OS cell line. The HPV genomic oligomers are extrachromosomal concatemeric molecules containing the viral genome in a head-to-tail orientation. The process of oligomerization does not depend on the topology of the input DNA, and it does not require any other viral factors besides replication proteins E1 and E2. We provide evidence that oligomerization of the HPV18 and HPV11 genomes involves homologous recombination. We also demonstrate oligomerization of the HPV18 and HPV11 genomes in SiHa, HeLa, and C-33 A cell lines and provide examples of oligomeric HPV genomes in clinical samples obtained from HPV-infected patients.

Papillomavirus binding factor (PBF) is an intrinsically disordered protein with potential participation in osteosarcoma genesis, in silico evidence.

BACKGROUND: Papillomavirus binding factor (PBF) or zinc finger protein 395 is a transcription factor associated to a poor prognosis in patients with osteosarcoma, an aggressive bone cancer that predominantly affects adolescents. To investigate the role of the PBF protein in the osteosarcoma genesis, in this paper we present the bioinformatics analysis of physicochemical properties of PBF and its probable interactions with several key cellular targets. RESULTS: The physicochemical characteristics determined to PBF, disorder-promoting amino acids, flexibility, hydrophobicity, prediction of secondary and tertiary structures and probability to be crystallized, supported that this protein can be considered as an intrinsically disordered protein (IDP), with a zinc finger-like domain. The in silico analysis to find out PBF interactions with cellular factors, confirmed the experimentally demonstrated interaction of PBF with two key cellular proteins involved in regulation of cellular apoptosis, 14-3-3ß and Scythe/BAT3 proteins. Furthermore, other interactions were found with proteins like HDAC1 and TPR which are known to be deregulated in several cancers. Experimental confirmation of specific interactions will contribute to understand the osteosarcoma process and might lead to the identification of new targets for diagnosis and treatments. CONCLUSIONS: According to the in silico PBF analyses, this protein can be considered as an IDP capable to bind several key cellular factors, and these interactions might play an important role in the osteosarcoma process.

Combination of targeting gene-viro therapy with recombinant Fowl-pox viruses with HN and VP3 genes on mouse osteosarcoma.

BACKGROUND: Osteosarcoma is an aggressive cancerous neoplasm arising from primitive transformed cells of mesenchymal origin that exhibit osteoblastic differentiation and produce malignant osteoid. With the rapid development of tumor molecular biology, gene and viral therapy, a highly promising strategy for the treatment, has shown some therapeutic effects. OBJECTIVES: To study the strategy of cooperative cancer gene therapy, previously, we explored the antitumor effects of recombinant Fowl-pox viruses (FPVs) with both HN (hemagglutinin-neuramidinase) and VP3 genes on mouse osteosarcoma. MATERIALS AND METHODS: We constructed vFV-HN, vFV-VP3 and vFV-HN-VP3 inserting CAV VP3 gene, NDV HN gene into fowlpox virus. S180 osteosarcoma were transfected with Recombinant Fowl-pox viruses (FPVs). These cell lines stably expressing tagged proteins were selected by culturing in medium containing puromycin (2 µg/ml) and confirmed by immunoblotting and immunostaining. S180 osteosarcoma model with BALB/c mice and nude mice were established and the vFPV viruses as control, vFV-HN, vFV-VP3, vFV-HN-VP3 were injected into the tumor directly. The rate of tumor growth, tumor suppression and the sialic acid levels in serum were examined and the tumor tissues were analyzed by the method of immunohistochemistry. Flow cytometric analysis was performed using a FACSCalibur flow cytometer. A total of 100,000 events were analyzed for each sample and the experiment was repeated at least twice. RESULTS: Our data indicated that vFV-HN, vFV-VP3 and vFV-HN-VP3 all had growth inhibition effects, the inhibition rate of vFV-HN-VP3 group was 51.7%, which was higher than that of vFV-HN, vFV-VP3 group and control group (p < 0.01). The sialic acid level of vFV-HN-VP3 group in mouse serum was 4.22±0.27 mmol/l, which was lower than that of other groups (p < 0.01). CONCLUSIONS: These results suggest that genes into mouse osteosarcoma cancer cells can cause cell a specificity anti-tumor immune activity, suppress tumor growth, and increase the survival rate of the tumor within host.