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.

Parallel G-quadruplexes recruit the HSV-1 transcription factor ICP4 to promote viral transcription in herpes virus-infected human cells.

G-quadruplexes (G4s) are four-stranded nucleic acid structures abundant at gene promoters. They can adopt several distinctive conformations. G4s have been shown to form in the herpes simplex virus-1 (HSV-1) genome during its viral cycle. Here by cross-linking/pull-down assay we identified ICP4, the major HSV-1 transcription factor, as the protein that most efficiently interacts with viral G4s during infection. ICP4 specific and direct binding and unfolding of parallel G4s, including those present in HSV-1 immediate early gene promoters, induced transcription in vitro and in infected cells. This mechanism was also exploited by ICP4 to promote its own transcription. Proximity ligation assay allowed visualization of G4-protein interaction at the single selected G4 in cells. G4 ligands inhibited ICP4 binding to G4s. Our results indicate the existence of a well-defined G4-viral protein network that regulates the productive HSV-1 cycle. They also point to G4s as elements that recruit transcription factors to activate transcription in cells.

Combination immunotherapy using G-CSF and oncolytic virotherapy reduces tumor growth in osteosarcoma.

BACKGROUND: Osteosarcoma is the most common malignant solid tumor that affects bones, however, survival rates of patients with relapsed osteosarcoma have not improved in the last 30 years. Oncolytic virotherapy, which uses viruses designed to selectively replicate in cancer cells, has emerged as a promising treatment for solid tumors. Our group uses mesenchymal stem cells (MSCs) to transport oncolytic adenoviruses (OAds) to the tumor site, a therapeutic strategy called Celyvir. This treatment has been already applied in human patients, canine patients and different mouse models. In parallel, previous results have probed that administration of granulocyte-colony stimulating factor (G-CSF) increased immune infiltration in tumors. We then hypothesized that the mobilization of immune cells by G-CSF may increase the antitumor efficacy of Celyvir treatment by increasing the immune infiltration into the tumors. METHODS: In this study, we use a murine version of Celyvir consisting in murine MSCs carrying the murine OAd dlE102-here called OAd-MSCs-in an immunocompetent model of osteosarcoma. We tested the antitumoral efficacy of the combination of OAd-MSCs plus G-CSF. RESULTS: Our results show that treatment with OAd-MSCs or the union of OAd-MSCs with G-CSF (Combination) significantly reduced tumor growth of osteosarcoma in vivo. Moreover, treated tumors presented higher tumor infiltration of immune cells-especially tumor-infiltrating lymphocytes-and reduced T cell exhaustion, which seems to be enhanced in tumors treated with the Combination. The comparison of our results to those obtained from a cohort of pediatric osteosarcoma patients showed that the virotherapy induces immunological changes similar to those observed in patients with good prognosis. CONCLUSIONS: The results open the possibility of using cellular virotherapy for the treatment of bone cancers. Indeed, its combination with G-CSF may be considered for the improvement of the therapy.

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.

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.

Musculoskeletal oncology: patient triage and management during the COVID-19 pandemic.

Sarcoma treatment during the covid-19 pandemic is a new challenge. This patient population is often immunocompromised and potentially more susceptible to viral complications. Government guidelines highlight the need to minimize patient exposure to unnecessary hospital visits. However, those guidelines lack practical recommendations on ways to manage triage and diagnosis expressly for new cancer patients. Furthermore, there are no reports on the efficiency of the guidelines. One of the main issues in treating musculoskeletal tumours is the complexity and variability of presentation. We offer a triage model, used in a quaternary-referral musculoskeletal oncology centre, that allows us to maintain an open pathway for referral of new patients while minimizing exposure risks. A multidisciplinary approach and analysis of existing investigations allow for a pre-clinic evaluation. The model identifies 3 groups of patients: ■ Patients with suspected high-grade malignancy, or benign cases with aggressive features, both in need of further evaluation in the clinic and prompt treatment■ Patients with low-grade malignancy, and benign cases whose treatment is not urgent, that are managed during the pandemic by telemedicine, with reassurance and information about their illness■ Patients who can be managed by their local medical professionals In comparison to a pre-pandemic period, that approach resulted in a higher ratio of malignant-to-benign conditions for new patients seen in the clinic (3:4 vs. 1:3 respectively), thus using available resources more efficiently and prioritizing patients with suspected high-grade malignancy. We believe that this triage system could be applied in other surgical oncology fields during a pandemic.

Incidence and outcomes of severe acute respiratory syndrome coronavirus 2 infection in patients with metastatic castration-resistant prostate cancer.

BACKGROUND: Patients with cancer are at increased risk of complicated severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, but it is still unclear if the risk of mortality is influenced by cancer type or ongoing anti-cancer treatments. An interesting debate concerning the potential relationship between androgen deprivation therapy (ADT) and SARS-CoV-2 infection has recently been opened in the case of prostate cancer (PC), and the aim of this multi-centre cohort study was to investigate the incidence and outcomes of SARS-CoV-2 infection in patients with metastatic castration-resistant prostrate cancer (mCRPC). PATIENTS AND METHODS: We retrospectively reviewed the clinical records of patients with mCRPC who developed SARS-CoV-2 infection, and recorded their baseline clinical characteristics, their history of PC and SARS-CoV-2 infection, and their oncological status and treatment at the time of infection. The primary study end point was the death rate and the possible impact of the patients' PC-related history and treatments on mortality. RESULTS: Thirty-four of the 1433 patients with mCRPC attending the participating centres (2.3%) developed SARS-CoV-2 infection, 22 (64.7%) of whom were hospitalised. Most of the patients were symptomatic, the most frequent symptoms being fever (70.6%), dyspnoea (61.8%), cough (52.9%) and fatigue (38.2%). After a median follow-up of 21 days (interquartile range: 13-41), 13 patients had died (38.2%), 17 recovered (50.0%) and four (11.7%) were still infected. The number of treatments previously administered for mCRPC had a significant impact on mortality (p = 0.004). CONCLUSIONS: Our findings contribute additional data to the current debate concerning the postulated protective role of ADT, which seems to be less in patients with metastatic PC.

High-resolution analysis of Merkel Cell Polyomavirus in Merkel Cell Carcinoma reveals distinct integration patterns and suggests NHEJ and MMBIR as underlying mechanisms.

Merkel Cell Polyomavirus (MCPyV) is the etiological agent of the majority of Merkel Cell Carcinomas (MCC). MCPyV positive MCCs harbor integrated, defective viral genomes that constitutively express viral oncogenes. Which molecular mechanisms promote viral integration, if distinct integration patterns exist, and if integration occurs preferentially at loci with specific chromatin states is unknown. We here combined short and long-read (nanopore) next-generation sequencing and present the first high-resolution analysis of integration site structure in MCC cell lines as well as primary tumor material. We find two main types of integration site structure: Linear patterns with chromosomal breakpoints that map closely together, and complex integration loci that exhibit local amplification of genomic sequences flanking the viral DNA. Sequence analysis suggests that linear patterns are produced during viral replication by integration of defective/linear genomes into host DNA double strand breaks via non-homologous end joining, NHEJ. In contrast, our data strongly suggest that complex integration patterns are mediated by microhomology-mediated break-induced replication, MMBIR. Furthermore, we show by ChIP-Seq and RNA-Seq analysis that MCPyV preferably integrates in open chromatin and provide evidence that viral oncogene expression is driven by the viral promoter region, rather than transcription from juxtaposed host promoters. Taken together, our data explain the characteristics of MCPyV integration and may also provide a model for integration of other oncogenic DNA viruses such as papillomaviruses.

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.

Comparative RNA sequencing reveals that HPV16 E6 abrogates the effect of E6*I on ROS metabolism.

High-risk Human Papillomavirus infections are responsible for anogenital and oropharyngeal cancers. Alternative splicing is an important mechanism controlling HPV16 gene expression. Modulation in the splice pattern leads to polycistronic HPV16 early transcripts encoding a full length E6 oncoprotein or truncated E6 proteins, commonly named E6*. Spliced E6*I transcripts are the most abundant RNAs produced in HPV-related cancers. To date, the biological function of the E6*I isoform remains controversial. In this study, we identified, by RNA sequencing, cellular targets deregulated by E6*I, among which genes related to ROS metabolism. Concomitantly, E6*I-overexpressing cells display high levels of ROS. However, co-overexpression of both E6 and E6*I has no effect on ROS production. In HPV16-infected cells expressing different E6/E6*I levels, we show that the newly identified targets CCL2 and RAC2 are increased by E6*I but decreased by E6 expression, suggesting that E6 abrogates the effect of E6*I. Taken together, these data support the idea that E6*I acts independently of E6 to increase ROS production and that E6 has the ability to counteract the effects of E6*I. This asks the question of how E6*I can be considered separately of E6 in the natural history of HPV16 infection.

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.

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.

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.

A herpes simplex virus type 2-encoded microRNA promotes tumor cell metastasis by targeting suppressor of cytokine signaling 2 in lung cancer.

Certain viruses use microRNAs to regulate the expression of their own genes, host genes, or both. A number of microRNAs expressed by herpes simplex virus type 2 have been confirmed by previous studies. However, whether these microRNAs play a role in the metastasis of lung cancers and how these viral microRNAs precisely regulated the tumor biological process in lung cancer bone metastasis remain obscure. We recently identified the high expression of an acutely and latently expressed viral microRNA, Hsv2-miR-H9-5p, encoded by herpes simplex virus type 2 latency-associated transcript through microarray and quantitative polymerase chain reaction analyses which compared the expression of microRNAs in bone metastasis from lung cancer with primary lung cancers. We now reported that Hsv2-miR-H9-5p was highly expressed in bone metastasis and closely associated with pathological and metastatic processes of lung cancers. The functions of Hsv2-miR-H9-5p were determined by overexpression which results in an increase in survival, migration, and invasion of lung cancer cells in vitro. We determined that Hsv2-miR-H9-5p directly targeted SOCS2 mechanistically by dual-luciferase reporter assay. Then, we investigated the functions of SOCS2 in the progress of lung cancers. Reduction of SOCS2 dosage by hsv2-miR-H9-5p induced increased migration and invasion of lung cancer cells. Overexpression of SOCS2 inverted these phenotypes generated by hsv2-miR-H9-5p, indicating the potential roles of SOCS2 in Hsv2-miR-H9-5p-driven metastasis in lung cancers. The results highlighted that Hsv2-miR-H9-5p regulated and contributed to bone metastasis of lung cancers. We proposed that Hsv2-miR-H9-5p could be used as a potential target in lung cancer therapy.

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.

HIV-related Kaposi's Sarcoma with Musculoskeletal Involvement in the Modern Antiretroviral Era.

AIM: To describe the patterns of disease and clinical outcomes of MSK-KS in people living with HIV in the era of (combination anti-retroviral therapy cART). PATIENTS AND METHODS: We reviewed our prospectively collected dataset of patients with HIV with biopsy-proven KS; 17 out of 1,489 seropositive patients were identified with subsequent evidence of MSK involvement by KS. We collected data with regards to clinicopathological parameters and radiological patterns of disease. RESULTS: Fourteen patients (82.4%) had AIDS Clinical Trials Group T1 stage disease at presentation including four (23.5%) with non-nodal visceral disease. At the time of MSK-KS diagnosis, more than 80% of 14 patients had excellent HIV control. The median interval between initial KS to MSK-KS diagnosis was 3.3 years. Five-year overall survival rate from initial KS diagnosis was 76%, and 60% from MSK-KS diagnosis. The majority of patients were asymptomatic and MSK-KS involvement was demonstrated during imaging prompted by progression of their mucocutaneous KS. The majority of lesions were lytic with cortical involvement on cross-sectional imaging, whereas a soft-tissue component was commonly associated with long-bone involvement. CONCLUSION: MSK-KS continues to be a rare entity in the modern era of cART, however patients appear to experience significantly improved survival.

The Oncolytic Adenovirus VCN-01 as Therapeutic Approach Against Pediatric Osteosarcoma.

PURPOSE: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Despite aggressive chemotherapy, more than 30% of patients do not respond and develop bone or lung metastasis. Oncolytic adenoviruses engineered to specifically destroy cancer cells are a feasible option for osteosarcoma treatment. VCN-01 is a replication-competent adenovirus specifically engineered to replicate in tumors with a defective RB pathway, presents an enhanced infectivity through a modified fiber and an improved distribution through the expression of a soluble hyaluronidase. The aim of this study is to elucidate whether the use of VCN-01 would be an effective therapeutic strategy for pediatric osteosarcoma. EXPERIMENTAL DESIGN: We used osteosarcoma cell lines established from patients with metastatic disease (531MII, 678R, 588M, and 595M) and a commercial cell line (143B). MTT assays were carried out to evaluate the cytotoxicity of VCN-01. Hexon assays were used to evaluate the replication of the virus. Western blot analysis was performed to assess the expression levels of viral proteins and autophagic markers. The antitumor effect of VCN-01 was evaluated in orthotopic and metastatic osteosarcoma murine animal models. RESULTS: This study found that VCN-01, a new generation genetically modified oncolytic adenovirus, administered locally or systemically, had a potent antisarcoma effect in vitro and in vivo in mouse models of intratibial and lung metastatic osteosarcoma. Moreover, VCN-01 administration showed a safe toxicity profile. CONCLUSIONS: These results uncover VCN-01 as a promising strategy for osteosarcoma, setting the bases to propel a phase I/II trial for kids with this disease. Clin Cancer Res; 22(9); 2217-25. ©2015 AACR.