Theoretical study on effect of confinement on flexural ductility of normal and high-strength concrete beams

Compared with normal concrete, high-strength concrete has higher strength but is generally more brittle. Its use in a reinforced concrete structure, if not properly controlled, could lead to an unsustainable reduction in ductility. However, confinement could be provided to improve the ductility of the structure. In this study, the effects of concrete strength and confinement on the flexural ductility of reinforced concrete beams have been evaluated by means of complete moment-curvature analysis of beam sections cast in different concretes and provided with different confinements. The results reveal that the use of high-strength concrete at a constant tension steel ratio would increase the flexural ductility, but at a constant tension to balanced steel ratio would decrease the flexural ductility. In contrast, the provision of confinement would always increase the flexural ductility. It does this in two ways: first, it increases the balanced steel ratio so that, at the same tension steel ratio, the tension to balanced steel ratio is decreased; and second, it increases the residual strength and ductility of the concrete so that, at the same tension to balanced steel ratio, the flexural ductility of the beam section is increased.published_or_final_versio

Cancer Immunotherapy : Evolving Oncolytic viruses and CAR T-cells

In the last decade cancer immunotherapy has taken huge strides forward from bench to bedside and being approved as drugs. Cancer immunotherapy harnesses the power of patient’s own immune system to fight cancer. Approaches are diverse and include antibodies, therapeutic vaccines, adoptively transferred T-cells, immune checkpoint inhibitors, oncolytic viruses and immune cell activators such as toll-like receptor (TLR) agonists. Excellent clinical responses have been observed for certain cancers with checkpoint antibodies and chimeric antigen receptor (CAR)-engineered T-cells. It is however becoming evident that strategies need to be combined for broader effective treatment responses because cancers evolve to escape immune recognition. A conditionally replication-competent oncolytic adenovirus (Ad5PTDf35-[Δ24]) was engineered to secrete Helicobacter pylori Neutrophil Activating Protein (HP-NAP, a TLR-2 agonist) to combine viral oncolysis and immune stimulation. Treatment with Ad5PTDf35-[Δ24-sNAP] improved survival of mice bearing human neuroendocrine tumors (BON). Expression of HP-NAP in the tumor microenvironment promoted neutrophil infiltration, proinflammatory cytokine secretion and increased necrosis. We further studied the ability of HP-NAP to activate dendritic cells (DCs) a key player in priming T-cell responses. HP-NAP phenotypically matured and activated DCs to secrete the T-helper type-1 (Th-1) polarizing cytokine IL-12. HP-NAP-matured DCs were functional; able to migrate to draining lymph nodes and prime antigen-specific T-cell proliferation. CAR T-cells were engineered to secrete HP-NAP upon T-cell activation. Secreted HP-NAP was able to mature DCs, leading to a reciprocal effect on the CAR T-cells with improved cytotoxicity in vitro. Semliki Forest virus (SFV), an oncolytic virus with natural neuro-tropism was tagged with central nervous system (CNS)-specific microRNA target sequences for miR124, miR125 and miR134 to selectively attenuate virus replication in healthy CNS cells. Systemic infection of mice with the SFV4miRT did not cause encephalitis, while it retained its ability to replicate in tumor cells and cure a big proportion of mice bearing syngeneic neuroblastoma and gliomas. Therapeutic efficacy of SFV4miRT inversely correlated with type-I antiviral interferon response (IFN-β) mounted by tumor cells. In summary, combining immunotherapeutic strategies with HP-NAP is a promising approach to combat cancers and SFV4miRT is an excellent candidate for treatment of neuroblastomas and gliomas

Cancer Immunotherapy : Evolving Oncolytic viruses and CAR T-cells

In the last decade cancer immunotherapy has taken huge strides forward from bench to bedside and being approved as drugs. Cancer immunotherapy harnesses the power of patient’s own immune system to fight cancer. Approaches are diverse and include antibodies, therapeutic vaccines, adoptively transferred T-cells, immune checkpoint inhibitors, oncolytic viruses and immune cell activators such as toll-like receptor (TLR) agonists. Excellent clinical responses have been observed for certain cancers with checkpoint antibodies and chimeric antigen receptor (CAR)-engineered T-cells. It is however becoming evident that strategies need to be combined for broader effective treatment responses because cancers evolve to escape immune recognition. A conditionally replication-competent oncolytic adenovirus (Ad5PTDf35-[Δ24]) was engineered to secrete Helicobacter pylori Neutrophil Activating Protein (HP-NAP, a TLR-2 agonist) to combine viral oncolysis and immune stimulation. Treatment with Ad5PTDf35-[Δ24-sNAP] improved survival of mice bearing human neuroendocrine tumors (BON). Expression of HP-NAP in the tumor microenvironment promoted neutrophil infiltration, proinflammatory cytokine secretion and increased necrosis. We further studied the ability of HP-NAP to activate dendritic cells (DCs) a key player in priming T-cell responses. HP-NAP phenotypically matured and activated DCs to secrete the T-helper type-1 (Th-1) polarizing cytokine IL-12. HP-NAP-matured DCs were functional; able to migrate to draining lymph nodes and prime antigen-specific T-cell proliferation. CAR T-cells were engineered to secrete HP-NAP upon T-cell activation. Secreted HP-NAP was able to mature DCs, leading to a reciprocal effect on the CAR T-cells with improved cytotoxicity in vitro. Semliki Forest virus (SFV), an oncolytic virus with natural neuro-tropism was tagged with central nervous system (CNS)-specific microRNA target sequences for miR124, miR125 and miR134 to selectively attenuate virus replication in healthy CNS cells. Systemic infection of mice with the SFV4miRT did not cause encephalitis, while it retained its ability to replicate in tumor cells and cure a big proportion of mice bearing syngeneic neuroblastoma and gliomas. Therapeutic efficacy of SFV4miRT inversely correlated with type-I antiviral interferon response (IFN-β) mounted by tumor cells. In summary, combining immunotherapeutic strategies with HP-NAP is a promising approach to combat cancers and SFV4miRT is an excellent candidate for treatment of neuroblastomas and gliomas

The cancer-immunity cycle as rational design for synthetic cancer drugs : Novel DC vaccines and CAR T-cells

Cell therapy is an advanced form of cancer immunotherapy that has had remarkable clinical progress in the past decade in the search for cure of cancer. Most success has been achieved for chimeric antigen receptor (CAR) T-cells where CAR T-cells targeting CD19 show very high complete response rates for patients with refractory acute B-cell acute lymphoblastic leukemia (ALL) and are close to approval for this indication. CD19 CAR T-cells are also effective against B-cell chronic lymphoblastic leukemia (CLL) and B-cell lymphomas. Although encouraging, CAR T-cells have not yet proven clinically effective for solid tumors. This is mainly due to the lack of specific and homogenously expressed targets to direct the T-cells against and a hostile immunosuppressive tumor microenvironment in solid tumors. Cancer vaccines based on dendritic cells (DC) are also making progress although clinical efficacy is still lacking. The likelihood of success is however increasing now when individual tumors can be sequences and patient-specific neoepitopes identified. Neoepitopes and/or neoantigens can then be included in patient based DC vaccines. This review discusses recent advancements of DC vaccines and CAR T-cells with emphasis on the cancer-immunity cycle, and current efforts to design novel cell therapies

Tumor angiogenesis : causes, consequences, challenges and opportunities

Tumor vascularization occurs through several distinct biological processes, which not only vary between tumor type and anatomic location, but also occur simultaneously within the same cancer tissue. These processes are orchestrated by a range of secreted factors and signaling pathways and can involve participation of non-endothelial cells, such as progenitors or cancer stem cells. Anti-angiogenic therapies using either antibodies or tyrosine kinase inhibitors have been approved to treat several types of cancer. However, the benefit of treatment has so far been modest, some patients not responding at all and others acquiring resistance. It is becoming increasingly clear that blocking tumors from accessing the circulation is not an easy task to accomplish. Tumor vessel functionality and gene expression often differ vastly when comparing different cancer subtypes, and vessel phenotype can be markedly heterogeneous within a single tumor. Here, we summarize the current understanding of cellular and molecular mechanisms involved in tumor angiogenesis and discuss challenges and opportunities associated with vascular targeting

Insertion of the Type-I IFN Decoy Receptor B18R in a miRNA-Tagged Semliki Forest Virus Improves Oncolytic Capacity but Results in Neurotoxicity

Oncolytic Semliki Forest virus (SFV) has been suggested as a potential candidate for the treatment of glioblastoma and neuroblastoma. However, the oncolytic capacity of SFV is restricted by the anti-viral type-I interferon (IFN) response. The aim of this study was to increase the oncolytic capacity of a microRNA target tagged SFV against glioblastoma by arming it with the Vaccinia-virus-encoded type-I IFN decoy receptor B18R (SFV4B18RmiRT) to neutralize type-I IFN response. Expression of B18R by SFV4B18RmiRT aided neutralization of IFN-b, which was shown by reduced STAT-1 phosphorylation and improved virus spread in plaque assays. B18R expression by SFV4 increased its oncolytic capacity in vitro against murine glioblastoma (CT-2A), regardless of the presence of exogenous IFN-b. Both SFV4B18RmiRT and SFV4miRT treatments controlled tumor growth in mice with syngeneic orthotopic gliomablastoma (CT-2A). However, treatment with SFV4B18RmiRT induced severe neurological symptoms in some mice because of virus replication in the healthy brain. Neither neurotoxicity nor virus replication in the brain was observed when SFV4miRT was administered. In summary, our results indicate that the oncolytic capacity of SFV4 was improved in vitro and in vivo by incorporation of B18R, but neurotoxicity of the virus was increased, possibly due to loss of microRNA targets

An infection-enhanced oncolytic adenovirus secreting H. pylori neutrophil-activating protein with therapeutic effects on neuroendocrine tumors

Helicobacter pylori Neutrophil Activating Protein (HP-NAP) is a major virulence factor involved in H. pylori infection. HP-NAP can mediate anti-tumor effects by recruiting neutrophils and inducing Th1-type differentiation in the tumor microenvironment. It therefore holds strong potential as a therapeutic gene. Here, we armed a replication-selective, infection-enhanced adenovirus with secretory HP-NAP, Ad5PTDf35-[Δ24-sNAP], and evaluated its therapeutic efficacy against neuroendocrine tumors. We observed that it could specifically infect and eradicate a wide range of tumor cells lines from different origin in vitro. Insertion of secretory HP-NAP did not affect the stability or replicative capacity of the virus and infected tumor cells could efficiently secrete HP-NAP. Intratumoral administration of the virus in nude mice xenografted with neuroendocrine tumors improved median survival. Evidence of biological HP-NAP activity was observed 24 hours after treatment with neutrophil infiltration in tumors and an increase of proinflammatory cytokines such as TNF-α and MIP2-α in the systemic circulation. Furthermore, evidence of Th1-type immune polarization was observed as a result of increase in IL-12/23 p40 cytokine concentrations 72 hours post-virus administration. Our observations suggest that HP-NAP can serve as a potent immunomodulator in promoting anti-tumor immune response in the tumor microenvironment and enhance the therapeutic effect of oncolytic adenovirus.De två (2) sista författarna delar sistaförfattarskapet.Open access under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License (CC BY-NC-ND). 2013.Supported funds:The Swedish Children Cancer Foundation(PROJ10/027), Gunnar Nilsson’s Cancer Foundation, Marcus and Marianne Wallenberg’sFoundation</p

CAR T cells expressing a bacterial virulence factor trigger potent bystander antitumour responses in solid cancers

Chimeric antigen receptor T cells (CAR T cells) are effective against haematologic malignancies. However, in solid tumours, their potency is hampered by local immunosuppression and by the heterogeneous expression of the antigen that the CAR targets. Here we show that CAR T cells expressing a pluripotent pro-inflammatory neutrophil-activating protein (NAP) from Helicobacter pylori trigger endogenous bystander T-cell responses against solid cancers. In mice with subcutaneous murine pancreatic ductal adenocarcinomas, neuroblastomas or colon carcinomas, CAR(NAP) T cells led to slower tumour growth and higher survival rates than conventional mouse CAR T cells, regardless of target antigen, tumour type and host haplotype. In tumours with heterogeneous antigen expression, NAP secretion induced the formation of an immunologically 'hot' microenvironment that supported dendritic cell maturation and bystander responses, as indicated by epitope spreading and infiltration of cytotoxic CD8(+) T cells targeting tumour-associated antigens other than the CAR-targeted antigen. CAR T cells armed with NAP neither increased off-tumour toxicity nor hampered the efficacy of CAR T cells, and hence may have advantageous translational potential. T cells expressing a pluripotent pro-inflammatory neutrophil-activating protein from Helicobacter pylori trigger endogenous bystander T-cell responses against solid cancers

Safe engineering of CAR T cells for adoptive cell therapy of cancer using long-term episomal gene transfer

Chimeric antigen receptor (CAR) T-cell therapy is a new successful treatment for refractory B-cell leukemia. Successful therapeutic outcome depends on long-term expression of CAR transgene in T cells, which is achieved by delivering transgene using integrating gamma retrovirus (RV) or lentivirus (LV). However, uncontrolled RV/LV integration in host cell genomes has the potential risk of causing insertional mutagenesis. Herein, we describe a novel episomal long-term cell engineering method using non-integrating lentiviral (NILV) vector containing a scaffold/matrix attachment region (S/MAR) element, for either expression of transgenes or silencing of target genes. The insertional events of this vector into the genome of host cells are below detection level. CD19 CAR T cells engineered with a NILV-S/MAR vector have similar levels of CAR expression as T cells engineered with an integrating LV vector, even after numerous rounds of cell division. NILV-S/MAR-engineered CD19 CAR T cells exhibited similar cytotoxic capacity upon CD19(+) target cell recognition as LV-engineered T cells and are as effective in controlling tumor growth in vivo We propose that NILV-S/MAR vectors are superior to current options as they enable long-term transgene expression without the risk of insertional mutagenesis and genotoxicity.GT och MR delar på andraförfattarskapet.</p