RESUMEN

Durable tumor responses and significant levels of disease control rates have been described in more than 20 advanced/metastatic cancer types with B7-family immune checkpoint-targeted anti-CTLA-4, anti-PD-1, and anti-PD-L1 monoclonal antibodies. These results and the recent approvals of ipilimumab, pembrolizumab, nivolumab and atezolizumab are currently revolutionizing the way we envision the future of cancer care. However these clinical benefits are not observed in all cancer types and in every patient. Therefore, our clinical challenge is to identify therapeutic strategies which could overcome the primary and secondary resistances to these novel cancer immunotherapies. Pattern recognition receptors (PRRs) are other critical costimulatory molecules of immune cells, notably myeloid cells (macrophages and dendritic cells). They were initially described as sensors for 'danger signals' released by pathogens (e.g. viral DNA and bacterial proteins). We know now that PRRs can also be recruited and activated upon recognition of endogenous stress signals such as molecules released upon self-cell death (e.g. ATP and HMGB1). Natural endo/exogenous or synthetic PRRs agonists have notably the ability to activate phagocytosis and antigen presentation by myeloid cells residing in the tumor micro-environment. In pre-clinical models, these PRRs agonists have also been shown to overcome the resistance to T-cell targeted immune checkpoints anti-CTLA-4 and anti-PD-1/PD-L1. This manuscript reviews the current knowledge on this major family of immune receptors and the molecules targeting them which are currently in clinical development.

Asunto(s)

Inmunoterapia , Neoplasias/terapia , Receptores de Reconocimiento de Patrones/agonistas , Humanos , Neoplasias/inmunología

RESUMEN

Genetic engineering of T cells with chimeric T-cell receptors (CARs) is an attractive strategy to treat malignancies. It extends the range of antigens for adoptive T-cell immunotherapy, and major mechanisms of tumor escape are bypassed. With this strategy we redirected immune responses towards the CD33 antigen to target acute myeloid leukemia. To improve in vivo T-cell persistence, we modified human Epstein Barr Virus-(EBV-) specific cytotoxic T cells with an anti-CD33.CAR. Genetically modified T cells displayed EBV and HLA-unrestricted CD33 bispecificity in vitro. In addition, though showing a myeloablative activity, they did not irreversibly impair the clonogenic potential of normal CD34(+) hematopoietic progenitors. Moreover, after intravenous administration into CD33(+) human acute myeloid leukemia-bearing NOD-SCID mice, anti-CD33-EBV-specific T cells reached the tumor sites exerting antitumor activity in vivo. In conclusion, targeting CD33 by CAR-modified EBV-specific T cells may provide additional therapeutic benefit to AML patients as compared to conventional chemotherapy or transplantation regimens alone.

RESUMEN

A mutation within one allele of the p53 tumor suppressor gene can inactivate the remaining wild-type allele in a dominant-negative manner and in some cases can exert an additional oncogenic activity, known as mutant p53 'gain of function' (GOF). To study the role of p53 mutations in prostate cancer and to discriminate between the dominant-negative effect and the GOF activity of mutant p53, we measured, using microarrays, the expression profiles of three immortalized prostate epithelial cultures expressing wild-type, inactivated p53 or mutated p53. Analysis of these gene expression profiles showed that both inactivated p53 and p53(R175H) mutant expression resulted in the upregulation of cell cycle progression genes. A second group, which was upregulated exclusively by mutant p53(R175H), was predominantly enriched in developmental genes. This group of genes included the Twist1, a regulator of metastasis and epithelial-mesenchymal transition (EMT). Twist1 levels were also elevated in metastatic prostate cancer-derived cell line DU145, in immortalized lung fibroblasts and in a subset of lung cancer samples, all in a mutant p53-dependent manner. p53(R175H) mutant bearing immortalized epithelial cells showed typical features of EMT, such as higher expression of mesenchymal markers, lower expression of epithelial markers and enhanced invasive properties in vitro. The mechanism by which p53(R175H) mutant induces Twist1 expression involves alleviation of the epigenetic repression. Our data suggest that Twist1 expression might be upregulated following p53 mutation in cancer cells.

Asunto(s)

Transición Epitelial-Mesenquimal , Proteínas Nucleares/metabolismo , Neoplasias de la Próstata/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteína 1 Relacionada con Twist/metabolismo , Sustitución de Aminoácidos , Línea Celular Transformada , Línea Celular Tumoral , Epigénesis Genética , Histonas/metabolismo , Humanos , Masculino , Mutación , Proteínas Nucleares/genética , Complejo Represivo Polycomb 1 , Regiones Promotoras Genéticas , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Represoras/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/fisiología , Proteína 1 Relacionada con Twist/genética , Regulación hacia Arriba

RESUMEN

A major obstacle to the expansion of abnormal cells with significant proliferative potential is the induction of programmed cell death. Consequently, oncogene-driven hyperproliferation must be associated with apoptosis inhibition to allow malignant outgrowth. The oncogenic cooperation of N-Myc and Twist-1 in the development of neuroblastoma, the most common and deadly solid tumour of childhood, perfectly illustrates such a process. N-Myc promotes cell proliferation, whereas Twist-1 counteracts its pro-apoptotic properties by knocking-down the ARF/p53 pathway. On the basis of numerous recent studies reporting its overexpression in a variety of human cancers, we discuss in this review the role of Twist-1 as a potent inhibitor of the cell safety programs engaged in response to an abnormal mitogenic activity.

Asunto(s)

Apoptosis , Neoplasias de la Mama/fisiopatología , Neuroblastoma/fisiopatología , Proliferación Celular , Progresión de la Enfermedad , Humanos , Metástasis de la Neoplasia , Proteínas Nucleares , Proteínas Proto-Oncogénicas c-myc/fisiología , Sobrevida , Proteína 1 Relacionada con Twist

RESUMEN

We have previously reported a set of Moloney murine leukemia virus derived envelopes retargeted to the Pit-2 phosphate transporter molecule, by insertion of the Pit-2 binding domain (BD) at the N terminus of the ecotropic retroviral envelope glycoproteins (S. Valsesia-Wittmann et al., J. Virol. 70:2059-2064, 1996). The resulting chimeric envelopes share two BDs: an additional N-terminal BD (Pit-2 BD) and the BD of the ecotropic envelope (mCAT-1 BD). By inserting a variety of different amino acid spacers between the two binding domains, we showed that retroviruses can potentially use the targeted cell surface receptor Pit-2, the ecotropic retroviral receptor mCAT-1, or both receptors cooperatively for entry into target cell (S. Valsesia-Wittmann et al., EMBO J 6:1214-1223, 1997). An extreme example of receptor cooperativity was encountered when envelopes with specific proline-rich interdomain spacers (PRO spacers) were tested: both receptors had to be coexpressed at the surface of the targeted cells to cooperatively allow infection. Here, we characterized the role of PRO spacer in the cooperation of receptors. We have shown that the particular organization of the PRO spacer-a beta-turn polyproline-was responsible for the cooperative effect. In the native configuration of the viruses, the structure masked the regions located downstream of the PRO spacer, thus the mCAT-1 BD. After interaction with the targeted Pit-2 receptor, the BD of the backbone envelope became accessible, and we demonstrated that interaction between the mCAT-1 BD and the mCAT-1 receptor is absolutely necessary. This interaction leads to natural fusion triggering and entry of viruses into targeted cells.

Asunto(s)

Proteínas Portadoras/metabolismo , Productos del Gen env/metabolismo , Virus de la Leucemia Murina/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores Virales/metabolismo , Simportadores , Células 3T3 , Secuencia de Aminoácidos , Animales , Células CHO , Proteínas Portadoras/genética , Línea Celular , Cricetinae , Productos del Gen env/genética , Humanos , Fusión de Membrana , Glicoproteínas de Membrana/genética , Ratones , Datos de Secuencia Molecular , Mutagénesis , Prolina/genética , Receptores Virales/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Cotransportadoras de Sodio-Fosfato , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo III

RESUMEN

We describe retrovirus particles carrying the fowl plague virus (FPV) hemagglutinin (HA). When expressed in cells providing Moloney murine leukemia virus (MoMLV) Gag and Pol proteins and a lacZ retroviral vector, FPV HA was found to be efficiently expressed, correctly processed, and stably incorporated into retroviral particles. HA-bearing retroviruses were infectious with a wide host range and were only 10-fold less infectious than retroviruses carrying wild-type MLV retroviral envelopes. We also coexpressed HA proteins in retroviral particles with chimeric MoMLV-derived envelope glycoproteins that efficiently retarget virus attachment but are only weakly fusogenic. Our results suggest that HA can in some cases enhance the fusion ability of these retroviral particles, depending on the cell surface molecule that is used as a receptor.

Asunto(s)

Hemaglutininas/genética , Virus de la Influenza A/genética , Virus de la Leucemia Murina/genética , Proteínas Virales de Fusión/genética , Animales , Productos del Gen gag/genética , Productos del Gen pol/genética , Operón Lac , Ratones , Recombinación Genética , Virión/genética

RESUMEN

We have constructed Moloney murine leukemia virus (MoMLV)-derived envelope glycoproteins (AMO) displaying an amino-terminal Ram-1-binding domain in which a variety of different amino acid spacers have been inserted between the displayed domain and the MoMLV surface (SU) subunit. Titres of retroviruses generated with these chimeric envelopes were enhanced on cells expressing both Ram-1 and Rec-1 receptors compared with the titres on cells expressing only one or other receptor type. The absolute viral titres and the degree of titre enhancement due to receptor cooperativity were highly variable between the different chimeric envelopes and were determined primarily by the properties of the interdomain spacer. An extreme example of receptor co-operativity was encountered when testing Ram-1-targeted AMOPRO envelopes with specific proline-rich interdomain spacers. AMOPRO viruses could not enter cells expressing only Rec-1 or only Ram-1 but could efficiently infect cells co-expressing both receptors. The data are consistent with a model for receptor co-operativity in which binding to the targeted (Ram-1) receptor triggers conformational rearrangements of the envelope that lead to complete unmasking of the hidden Rec-1-binding domain, thereby facilitating its interaction with the viral (Rec-1) receptor which leads to optimal fusion triggering.

Asunto(s)

Glicoproteínas de Membrana , Proteínas de Transporte de Fosfato , Receptores Virales/metabolismo , Retroviridae/metabolismo , Simportadores , Células 3T3 , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Proteínas Portadoras/química , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Cartilla de ADN/genética , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Datos de Secuencia Molecular , Estructura Molecular , Virus de la Leucemia Murina de Moloney/genética , Virus de la Leucemia Murina de Moloney/patogenicidad , Virus de la Leucemia Murina de Moloney/fisiología , Receptores Virales/química , Receptores Virales/genética , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Retroviridae/genética , Proteínas Cotransportadoras de Sodio-Fosfato , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo III , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/metabolismo

RESUMEN

We previously reported a strategy to redirect the retroviral host range by expressing single-chain antibodies (S. J. Russell, R. E. Hawkins, and G. Winter, Nucleic Acids Res. 21:1081-1085, 1993) or ligands (F.-L. Cosset, F. J Morling, Y. Takeuchi, R. A. Weiss, M. K. L. Collins, and S. J. Russell, J. Virol. 69:6314-6322, 1995) at the N terminus of Moloney murine leukemia virus (MoMLV) surface proteins (SU). Although such chimeric envelopes were able to bind the new receptors, the transduction efficiency of retargeted viruses was generally low. We hypothesized that conformational rearrangements of envelope glycoproteins were not optimally triggered following binding, and to overcome these postbinding blocks, we have generated here a set of chimeric MoMLV-derived envelopes targeted to the Ram-1 phosphate transporter in which we have varied the spacing between the Ram-1-binding domain and the MoMLV SU. All of the recombinant envelopes were correctly expressed on virions, and all bound efficiently to Ram-1. However, the interdomain spacing greatly affected the efficiency of gene transfer by retroviral vectors that had bound to Ram-1 via their chimeric envelopes. Optimal interdomain spacing allowed a 100-fold-increased viral transduction via Ram-1 compared to our previous results.

Asunto(s)

Virus de la Leucemia Murina de Moloney/fisiología , Proteínas de Transporte de Fosfato , Receptores Virales/metabolismo , Proteínas Oncogénicas de Retroviridae/metabolismo , Simportadores , Proteínas del Envoltorio Viral/metabolismo , Células 3T3 , Animales , Secuencia de Bases , Línea Celular , Clonación Molecular , ADN Viral , Humanos , Ratones , Datos de Secuencia Molecular , Virus de la Leucemia Murina de Moloney/genética , Mutagénesis , Receptores Virales/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Oncogénicas de Retroviridae/genética , Proteínas Cotransportadoras de Sodio-Fosfato , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo III , Transformación Genética , Proteínas del Envoltorio Viral/genética

RESUMEN

On the basis of theoretical structural and comparative studies of various avian leukosis virus SU (surface) envelope proteins, we have identified four small regions (I, II, III, and IV) in their receptor-binding domains that could potentially be involved in binding to receptors. From the envelope gene of an avian leukosis virus of subgroup A, we have constructed a set of SU mutants in which these regions were replaced by the coding sequence of FLA16, a 16-amino-acid RGD-containing peptide known to be the target for several cellular integrin receptors. Helper-free retroviral particles carrying a neo-lacZ retroviral vector were produced with the mutant envelopes. SU mutants in which regions III and IV were substituted yielded normal levels of envelope precursors but were not detectably processed or incorporated in viral particles. In contrast, substitutions in regions I and II did not affect the processing and the viral incorporation of SU mutants. When FLA16 was inserted in region II, it could be detected with antibodies against FLA16 synthetic peptide, but only when viral particles were deglycosylated. Viral particles with envelopes mutated in region I or II were able to infect avian cells through the subgroup A receptor at levels similar to those of the wild type. When viruses with envelopes containing FLA16 peptide in region II were applied to plastic dishes, they were found to promote binding of mammalian cells resistant to infection by subgroup A avian leukosis viruses but expressing the integrins recognized by FLA16. Deglycosylated helper-free viruses obtained by mild treatment with N-glycosidase F have been used to infect these mammalian cells, and infections have been monitored by neomycin selection. No neomycin-resistant clones could be obtained after infection by viruses with wild-type envelopes. Conversely, colonies were obtained after infection by viruses with envelopes bearing FLA16 in region II, and the genome of the retroviral vector was found correctly integrated in cell DNA of these colonies. By using a blocking peptide containing the minimal adhesive RGD sequence contained in FLA16, we have shown that preincubation of target cells could specifically inhibit infection by viruses with FLA16.

Asunto(s)

Virus de la Leucosis Aviar/patogenicidad , Proteínas del Envoltorio Viral/metabolismo , Secuencia de Aminoácidos , Animales , Virus de la Leucosis Aviar/genética , Virus de la Leucosis Aviar/metabolismo , Secuencia de Bases , Sitios de Unión , Vectores Genéticos , Humanos , Datos de Secuencia Molecular , Mutación , Oligodesoxirribonucleótidos , Ratas , Receptores Virales/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Homología de Secuencia de Aminoácido , Células Tumorales Cultivadas , Proteínas del Envoltorio Viral/genética , Virión