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Smac mimetic compounds (SMCs) are small molecule drugs that sensitize cancer cells to TNF-α-induced cell death and have multiple immunostimulatory effects through alterations in NF-κB signaling. The combination of SMCs with immunotherapies has been reported to result in durable cures of up to 40% in syngeneic, orthotopic murine glioblastoma (GBM) models. Herein, we find that SMC resistance is not due to a cell-intrinsic mechanism of resistance. We thus evaluated the contribution of GBM and brain stromal components to identify parameters leading to SMC efficacy and resistance. The common physiological features of GBM tumors, such as hypoxia, hyaluronic acid, and glucose deprivation were found not to play a significant role in SMC efficacy. SMCs induced the death of microglia and macrophages, which are the major immune infiltrates in the tumor microenvironment. This death of microglia and macrophages then enhances the ability of SMCs to induce GBM cell death. Conversely, astrocytes promoted GBM cell growth and abrogated the ability of SMCs to induce death of GBM cells. The astrocyte-mediated resistance can be overcome in the presence of exogenous TNF-α. Overall, our results highlight that SMCs can induce death of microglia and macrophages, which then provides a source of death ligands for GBM cells, and that the targeting of astrocytes is a potential mechanism for overcoming SMC resistance for the treatment of GBM.
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Astrocitos , Glioblastoma , Microambiente Tumoral , Glioblastoma/patología , Glioblastoma/tratamiento farmacológico , Glioblastoma/inmunología , Microambiente Tumoral/efectos de los fármacos , Animales , Humanos , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Línea Celular Tumoral , Ratones , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/inmunología , Factor de Necrosis Tumoral alfa/metabolismo , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Macrófagos/inmunología , Inflamación/patología , Inflamación/tratamiento farmacológico , Proteínas Mitocondriales/metabolismo , Proteínas Reguladoras de la Apoptosis/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones Endogámicos C57BLRESUMEN
Adult stem cells (ASCs) can be cultured with difficulty from most tissues, often requiring chemical or transgenic modification to achieve adequate quantities. We show here that mouse primary fibroblasts, grown in suspension, change from the elongated and flattened morphology observed under standard adherent culture conditions of generating rounded cells with large nuclei and scant cytoplasm and expressing the mesenchymal stem cell (MSC) marker (Sca1; Ly6A) within 24 h. Based on this initial observation, we describe here a suspension culture method that, irrespective of the lineage used, mouse fibroblast or primary human somatic cells (fibroblasts, hepatocytes and keratinocytes), is capable of generating a high yield of cells in spheroid form which display the expression of ASC surface markers, circumventing the anoikis which often occurs at this stage. Moreover, mouse fibroblast-derived spheroids can be differentiated into adipogenic and osteogenic lineages. An analysis of single-cell RNA sequence data in mouse fibroblasts identified eight distinct cell clusters with one in particular comprising approximately 10% of the cells showing high levels of proliferative capacity expressing high levels of genes related to MSCs and self-renewal as well as the extracellular matrix (ECM). We believe the rapid, high-yield generation of proliferative, multi-potent ASC-like cells via the process we term suspension-induced stem cell transition (SIST) could have significant implications for regenerative medicine.
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Células Madre Adultas , Células Madre Mesenquimatosas , Adulto , Humanos , Animales , Ratones , Células Madre , Diferenciación Celular , Células Madre Mesenquimatosas/metabolismo , Animales Modificados GenéticamenteRESUMEN
Background: The genesis of SMAC mimetic drugs is founded on the observation that many cancers amplify IAP proteins to facilitate their survival, and therefore removal of these pathways would re-sensitize the cells towards apoptosis. It has become increasingly clear that SMAC mimetics also interface with the immune system in a modulatory manner. Suppression of IAP function by SMAC mimetics activates the non-canonical NF-κB pathway which can augment T cell function, opening the possibility of using SMAC mimetics to enhance immunotherapeutics. Methods: We have investigated the SMAC mimetic LCL161, which promotes degradation of cIAP-1 and cIAP-2, as an agent for delivering transient costimulation to engineered BMCA-specific human TAC T cells. In doing so we also sought to understand the cellular and molecular effects of LCL161 on T cell biology. Results: LCL161 activated the non-canonical NF-κB pathway and enhanced antigen-driven TAC T cell proliferation and survival. Transcriptional profiling from TAC T cells treated with LCL161 revealed differential expression of costimulatory and apoptosis-related proteins, namely CD30 and FAIM3. We hypothesized that regulation of these genes by LCL161 may influence the drug's effects on T cells. We reversed the differential expression through genetic engineering and observed impaired costimulation by LCL161, particularly when CD30 was deleted. While LCL161 can provide a costimulatory signal to TAC T cells following exposure to isolated antigen, we did not observe a similar pattern when TAC T cells were stimulated with myeloma cells expressing the target antigen. We questioned whether FasL expression by myeloma cells may antagonize the costimulatory effects of LCL161. Fas-KO TAC T cells displayed superior expansion following antigen stimulation in the presence of LCL161, suggesting a role for Fas-related T cell death in limiting the magnitude of the T cell response to antigen in the presence of LCL161. Conclusions: Our results demonstrate that LCL161 provides costimulation to TAC T cells exposed to antigen alone, however LCL161 did not enhance TAC T cell anti-tumor function when challenged with myeloma cells and may be limited due to sensitization of T cells towards Fas-mediated apoptosis.
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Mieloma Múltiple , FN-kappa B , Humanos , FN-kappa B/metabolismo , Mieloma Múltiple/tratamiento farmacológico , Línea Celular Tumoral , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/metabolismoRESUMEN
BACKGROUND: Transgenes deliver therapeutic payloads to improve oncolytic virus immunotherapy. Transgenes encoded within oncolytic viruses are designed to be highly transcribed, but protein synthesis is often negatively affected by viral infection, compromising the amount of therapeutic protein expressed. Studying the oncolytic herpes simplex virus-1 (HSV1), we found standard transgene mRNAs to be suboptimally translated in infected cells. METHODS: Using RNA-Seq reads, we determined the transcription start sites and 5'leaders of HSV1 genes and uncovered the US11 5'leader to confer superior activity in translation reporter assays. We then incorporated this 5'leader into GM-CSF expression cassette in oncolytic HSV1 and compared the translationally adapted oncolytic virus with the conventional, leaderless, virus in vitro and in mice. RESULTS: Inclusion of the US11 5'leader in the GM-CSF transgene incorporated into HSV1 boosted translation in vitro and in vivo. Importantly, treatment with US11 5'leader-GM-CSF oncolytic HSV1 showed superior antitumor immune activity and improved survival in a syngeneic mouse model of colorectal cancer as compared with leaderless-GM-CSF HSV1. CONCLUSIONS: Our study demonstrates the therapeutic value of identifying and integrating platform-specific cis-acting sequences that confer increased protein synthesis on transgene expression.
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Herpesvirus Humano 1 , Virus Oncolíticos , Animales , Ratones , Herpesvirus Humano 1/genética , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Virus Oncolíticos/genética , Transgenes , Biosíntesis de ProteínasRESUMEN
Cells have the ability to communicate with their immediate and distant neighbors through the release of extracellular vesicles (EVs). EVs facilitate intercellular signaling through the packaging of specific cargo in all type of cells, and perturbations of EV biogenesis, sorting, release and uptake is the basis of a number of disorders. In this review, we summarize recent advances of the complex roles of the sphingolipid ceramide and lysosomes in the journey of EV biogenesis to uptake.
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Ceramidas , Vesículas Extracelulares , Ceramidas/metabolismo , Transporte de Proteínas , Vesículas Extracelulares/metabolismo , Transporte Biológico , LisosomasRESUMEN
Autophagy is a fundamental catabolic process essential for the maintenance of cellular and tissue homeostasis, as well as directly contributing to the control of invading pathogens. Unsurprisingly, this process becomes critical in supporting cellular dysregulation that occurs in cancer, particularly the tumor microenvironments and their immune cell infiltration, ultimately playing a role in responses to cancer therapies. Therefore, understanding "cancer autophagy" could help turn this cellular waste-management service into a powerful ally for specific therapeutics. For instance, numerous regulatory mechanisms of the autophagic machinery can contribute to the anti-tumor properties of oncolytic viruses (OVs), which comprise a diverse class of replication-competent viruses with potential as cancer immunotherapeutics. In that context, autophagy can either: promote OV anti-tumor effects by enhancing infectivity and replication, mediating oncolysis, and inducing autophagic and immunogenic cell death; or reduce OV cytotoxicity by providing survival cues to tumor cells. These properties make the catabolic process of autophagy an attractive target for therapeutic combinations looking to enhance the efficacy of OVs. In this article, we review the complicated role of autophagy in cancer initiation and development, its effect on modulating OVs and immunity, and we discuss recent progress and opportunities/challenges in targeting autophagy to enhance oncolytic viral immunotherapy.
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Autofagia , Inmunoterapia , Neoplasias/inmunología , Neoplasias/terapia , Carcinogénesis/patología , Humanos , Muerte Celular Inmunogénica , Neoplasias/virología , Virus Oncolíticos/fisiologíaRESUMEN
Deregulation of mRNA translation engenders many human disorders, including obesity, neurodegenerative diseases, and cancer, and is associated with pathogen infections. The role of eIF4E-dependent translational control in macrophage inflammatory responses in vivo is largely unexplored. In this study, we investigated the involvement of the translation inhibitors eIF4E-binding proteins (4E-BPs) in the regulation of macrophage inflammatory responses in vitro and in vivo. We show that the lack of 4E-BPs exacerbates inflammatory polarization of bone marrow-derived macrophages and that 4E-BP-null adipose tissue macrophages display enhanced inflammatory gene expression following exposure to a high-fat diet (HFD). The exaggerated inflammatory response in HFD-fed 4E-BP-null mice coincides with significantly higher weight gain, higher Irf8 mRNA translation, and increased expression of IRF8 in adipose tissue compared with wild-type mice. Thus, 4E-BP-dependent translational control limits, in part, the proinflammatory response during HFD. These data underscore the activity of the 4E-BP-IRF8 axis as a paramount regulatory mechanism of proinflammatory responses in adipose tissue macrophages.
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Proteínas Adaptadoras Transductoras de Señales/genética , Tejido Adiposo/metabolismo , Inflamación/genética , Factores Reguladores del Interferón/genética , Macrófagos/metabolismo , Biosíntesis de Proteínas/genética , Animales , Médula Ósea/metabolismo , Dieta Alta en Grasa/métodos , Factor 4E Eucariótico de Iniciación/genética , Expresión Génica/genética , Inflamación/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
A genome-wide small-interfering RNA-based screen identified the transcription factor Specificity Protein 3 (SP3) as a critical factor for Second mitochondrial-derived activator of caspase (Smac) mimetic-mediated killing of cancer cells. In concert with Nuclear Factor kappa B (NF-κB,) SP3 is required for the expression of the cytokine Tumor Necrosis Factor alpha (TNF-α) under basal and Smac mimetic-stimulated conditions.
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The controlled production and downstream signaling of the inflammatory cytokine tumor necrosis factor-α (TNF-α) are important for immunity and its anticancer effects. Although chronic stimulation with TNF-α is detrimental to the health of the host in several autoimmune and inflammatory disorders, TNF-α-contrary to what its name implies-leads to cancer formation by promoting cell proliferation and survival. Smac mimetic compounds (SMCs), small-molecule antagonists of inhibitor of apoptosis proteins (IAPs), switch the TNF-α signal from promoting survival to promoting death in cancer cells. Using a genome-wide siRNA screen to identify factors required for SMC-to-TNF-α-mediated cancer cell death, we identified the transcription factor SP3 as a critical molecule in both basal and SMC-induced production of TNF-α by engaging the nuclear factor κB (NF-κB) transcriptional pathway. Moreover, the promotion of TNF-α expression by SP3 activity confers differential sensitivity of cancer versus normal cells to SMC treatment. The key role of SP3 in TNF-α production and signaling will help us further understand TNF-α biology and provide insight into mechanisms relevant to cancer and inflammatory disease.
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Materiales Biomiméticos/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Neoplasias/metabolismo , Transducción de Señal/efectos de los fármacos , Factor de Transcripción Sp3/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Línea Celular , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Células Cultivadas , Humanos , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/metabolismo , Ratones , Proteínas Mitocondriales/metabolismo , FN-kappa B/genética , FN-kappa B/metabolismo , Neoplasias/genética , Neoplasias/patología , Interferencia de ARN , Transducción de Señal/genética , Factor de Transcripción Sp3/genética , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Smac mimetic compounds (SMCs) are anti-cancer drugs that antagonize Inhibitor of Apoptosis proteins, which consequently sensitize cancer cells to death in the presence of proinflammatory ligands such as tumor necrosis factor alpha (TNF-α). SMCs synergize with the attenuated oncolytic vesicular stomatitis virus (VSVΔ51) by eliciting an innate immune response, which is dependent on the endogenous production of TNF-α and type I interferon. To improve on this SMC-mediated synergistic response, we generated TNF-α-armed VSVΔ51 to produce elevated levels of this death ligand. Due to ectopic expression of TNF-α from infected cells, a lower viral dose of TNF-α-armed VSVΔ51 combined with treatment of the SMC LCL161 was sufficient to improve the survival rate compared to LCL161 and unarmed VSVΔ51 co-therapy. This improved response is attributed to a bystander effect whereby the spread of TNF-α from infected cells leads to the death of uninfected cells in the presence of LCL161. In addition, the treatments induced vascular collapse in solid tumors with a concomitant increase of tumor cell death, revealing another mechanism by which cytokine-armed VSVΔ51 in combination with LCL161 can kill tumor cells. Our studies demonstrate the potential for cytokine-engineered oncolytic virus and SMCs as a new combination immunotherapy for cancer treatment.
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This corrects the article DOI: 10.1038/ncomms14278.
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Monocytes and macrophages constitute the first line of defense of the immune system against external pathogens. Macrophages have a highly plastic phenotype depending on environmental conditions; the extremes of this phenotypic spectrum are a pro-inflammatory defensive role (M1 phenotype) and an anti-inflammatory tissue-repair one (M2 phenotype). The Inhibitor of Apoptosis (IAP) proteins have important roles in the regulation of several cellular processes, including innate and adaptive immunity. In this study we have analyzed the differential expression of the IAPs, NAIP, cIAP1 and cIAP2, during macrophage differentiation and polarization into M1 or M2. In polarized THP-1 cells and primary human macrophages, NAIP is abundantly expressed in M2 macrophages, while cIAP1 and cIAP2 show an inverse pattern of expression in polarized macrophages, with elevated expression levels of cIAP1 in M2 and cIAP2 preferentially expressed in M1. Interestingly, treatment with the IAP antagonist SMC-LCL161, induced the upregulation of NAIP in M2, the downregulation of cIAP1 in M1 and M2 and an induction of cIAP2 in M1 macrophages.
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Proteína 3 que Contiene Repeticiones IAP de Baculovirus/metabolismo , Diferenciación Celular/fisiología , Proteínas Inhibidoras de la Apoptosis/metabolismo , Macrófagos/metabolismo , Proteína Inhibidora de la Apoptosis Neuronal/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Proteínas Reguladoras de la Apoptosis , Western Blotting , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Citometría de Flujo , Expresión Génica , Perfilación de la Expresión Génica , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Macrófagos/citología , Macrófagos/efectos de los fármacos , Proteínas Mitocondriales/metabolismo , Monocitos/citología , Monocitos/metabolismo , ARN Mensajero/metabolismoRESUMEN
Small-molecule inhibitor of apoptosis (IAP) antagonists, called Smac mimetic compounds (SMCs), sensitize tumours to TNF-α-induced killing while simultaneously blocking TNF-α growth-promoting activities. SMCs also regulate several immunomodulatory properties within immune cells. We report that SMCs synergize with innate immune stimulants and immune checkpoint inhibitor biologics to produce durable cures in mouse models of glioblastoma in which single agent therapy is ineffective. The complementation of activities between these classes of therapeutics is dependent on cytotoxic T-cell activity and is associated with a reduction in immunosuppressive T-cells. Notably, the synergistic effect is dependent on type I IFN and TNF-α signalling. Furthermore, our results implicate an important role for TNF-α-producing cytotoxic T-cells in mediating the anti-cancer effects of immune checkpoint inhibitors when combined with SMCs. Overall, this combinatorial approach could be highly effective in clinical application as it allows for cooperative and complimentary mechanisms in the immune cell-mediated death of cancer cells.
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Antineoplásicos/farmacología , Neoplasias Encefálicas/tratamiento farmacológico , Glioblastoma/tratamiento farmacológico , Interferón-alfa/inmunología , Interferón beta/inmunología , Tiazoles/farmacología , Inmunidad Adaptativa/efectos de los fármacos , Animales , Antineoplásicos/síntesis química , Antígeno B7-H1/genética , Antígeno B7-H1/inmunología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/mortalidad , Línea Celular Tumoral , Femenino , Regulación de la Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/inmunología , Glioblastoma/genética , Glioblastoma/inmunología , Glioblastoma/mortalidad , Humanos , Inmunidad Innata/efectos de los fármacos , Memoria Inmunológica , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/inmunología , Interferón-alfa/genética , Interferón-alfa/farmacología , Interferón beta/genética , Interferón beta/farmacología , Ratones , Poli I-C/farmacología , Transducción de Señal , Análisis de Supervivencia , Linfocitos T Citotóxicos/efectos de los fármacos , Linfocitos T Citotóxicos/inmunología , Tiazoles/síntesis química , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/farmacología , Vesiculovirus/genética , Vesiculovirus/inmunología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Rhabdomyosarcoma (RMS), a neoplasm characterized by undifferentiated myoblasts, is the most common soft tissue tumour in children. Therapeutic resistance is common in RMS and is often caused by acquired defects in the cellular apoptotic program. Smac mimetic compounds (SMCs) are a novel class of inhibitor of apoptosis (IAP) antagonists that are currently under clinical development as cancer therapeutics. We previously reported that cIAP1 is overexpressed in human primary RMS tumours and in patient-derived RMS cell lines where it drives resistance to apoptosis. In this study, we investigated whether inflammatory cytokine production triggered by activators of innate immunity synergizes with LCL161 to induce bystander killing of RMS cells in vitro and in vivo. Indeed, we show that innate immune stimuli (oncolytic virus (VSVΔ51-GFP), interferon γ (IFNγ), and tumour necrosis factor-like weak inducer of apoptosis (TWEAK)) combine with SMCs in vitro to reduce cell viability in the Kym-1 RMS cancer cell line. Other human RMS cell lines (RH36, RH41, RD, RH18, RH28, and RH30) and the murine RMS cell line 76-9 are resistant to treatment with LCL161 alone or in combination with immune stimulants in in vitro cell viability assays. In contrast, we report that the combination of LCL161 and VSVΔ51-GFP reduces tumour volume and prolongs survival in a 76-9 syngeneic murine model. Our results support further exploration of the combined use of IAP antagonists and innate immune stimuli as a therapeutic approach for RMS cancers.
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Imitación Molecular , Viroterapia Oncolítica , Virus Oncolíticos , Rabdomiosarcoma/inmunología , Rabdomiosarcoma/patología , Tiazoles/farmacología , Animales , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/inmunología , Terapia Combinada , Modelos Animales de Enfermedad , Femenino , Humanos , Inmunidad Innata/efectos de los fármacos , Factor 1 Regulador del Interferón/genética , Factor 1 Regulador del Interferón/metabolismo , Ratones , Virus Oncolíticos/genética , Rabdomiosarcoma/genética , Rabdomiosarcoma/terapia , Carga Tumoral , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Members of the inhibitor of apoptosis (IAP) family control several critical aspects of innate immunity, cell death, and tumorigenesis. Small molecule antagonists that target specific IAP oncoproteins, primarily cIAP1 and cIAP2, but potentially also XIAP and Livin, modulate distinct immune signal transduction pathways that can lead to an increased sensitivity of tumors cells to cytokine-mediated apoptosis. These antagonists are based on the structure of an endogenous cellular IAP inhibitor called Smac. Smac is normally sequestered within the mitochondria and is released into the cytoplasm upon cell death stimuli, thereby overcoming the anti-apoptotic action of the IAPs. The therapeutic usefulness of recombinant tumoricidal cytokines to treat cancer patients is principally limited due to their unacceptable adverse side effects. Therefore, investigators have sought to develop alternative regimens that do not rely on exogenously delivered death ligands. These approaches include the stimulation of the immune system with oncolytic virus-based agents or Toll-like receptor agonists in combination with Smac mimetics. Similarly, preclinical combination immunotherapy studies reveal that recombinant interferon synergizes with Smac mimetics to kill cancer. This strategy opens up new therapeutic avenues for anti-cancer therapy by modulating specific immune-mediated death pathways employing unique dual-pronged combinatorial approaches.
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Apoptosis/inmunología , Inmunoterapia/métodos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Mitocondriales/metabolismo , Neoplasias/terapia , Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis , Proteína 3 que Contiene Repeticiones IAP de Baculovirus , Citocinas/inmunología , Humanos , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Proteínas Inhibidoras de la Apoptosis/metabolismo , Interferón alfa-2 , Interferón-alfa/uso terapéutico , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/metabolismo , Neoplasias/inmunología , Proteínas Recombinantes/uso terapéutico , Transducción de Señal/inmunología , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Ubiquitina-Proteína Ligasas/antagonistas & inhibidores , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
A dual immunotherapy approach employing small-molecule inhibitors of apoptosis (IAP) protein antagonists in combination with innate immune stimuli has proven to be highly synergistic and effective in animal tumor models. This strategy overcomes many of the limitations of either single agent therapy and our results suggest that the combination could be easily and effectively translated to the clinic.
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Smac mimetic compounds (SMC), a class of drugs that sensitize cells to apoptosis by counteracting the activity of inhibitor of apoptosis (IAP) proteins, have proven safe in phase 1 clinical trials in cancer patients. However, because SMCs act by enabling transduction of pro-apoptotic signals, SMC monotherapy may be efficacious only in the subset of patients whose tumors produce large quantities of death-inducing proteins such as inflammatory cytokines. Therefore, we reasoned that SMCs would synergize with agents that stimulate a potent yet safe "cytokine storm." Here we show that oncolytic viruses and adjuvants such as poly(I:C) and CpG induce bystander death of cancer cells treated with SMCs that is mediated by interferon beta (IFN-ß), tumor necrosis factor alpha (TNF-α) and/or TNF-related apoptosis-inducing ligand (TRAIL). This combinatorial treatment resulted in tumor regression and extended survival in two mouse models of cancer. As these and other adjuvants have been proven safe in clinical trials, it may be worthwhile to explore their clinical efficacy in combination with SMCs.
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Antineoplásicos/farmacología , Proteínas Reguladoras de la Apoptosis/farmacología , Muerte Celular/efectos de los fármacos , Neoplasias Experimentales/tratamiento farmacológico , Animales , Antineoplásicos/uso terapéutico , Proteínas Reguladoras de la Apoptosis/uso terapéutico , Citocinas/metabolismo , Sinergismo Farmacológico , Femenino , Células HEK293 , Células HT29 , Humanos , Ratones , Ratones Endogámicos BALB C , Oligodesoxirribonucleótidos/farmacología , Oligodesoxirribonucleótidos/uso terapéutico , Viroterapia Oncolítica , Poli I-C/farmacología , Poli I-C/uso terapéuticoRESUMEN
The inhibitor of apoptosis (IAP) genes are critical regulators of multiple pathways that control cell death, proliferation, and differentiation. Several members of the IAP family regulate innate and adaptive immunity through modulation of signal transduction pathways, cytokine production, and cell survival. The regulation of immunity by the IAPs is primarily mediated through the ubiquitin ligase function of cellular IAP (cIAP)1, cIAP2, and X-linked IAP (XIAP), the targets of which impact nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signalling pathways. In addition, neuronal apoptosis inhibitory protein (NAIP), cIAP1, and cIAP2 modulate innate immune responses through control of the inflammasome complex. This review examines the role of mammalian IAPs in regulating immunity and describes the implications of a new class of pan-IAP antagonists for the treatment of immune disorders.
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Apoptosis , Proteínas Inhibidoras de la Apoptosis/inmunología , Transducción de Señal , Inmunidad Adaptativa , Animales , Humanos , Inmunidad Innata , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Proteínas Inhibidoras de la Apoptosis/genética , FN-kappa B/metabolismoRESUMEN
Neurons are an important source of the secreted morphogen Sonic hedgehog (Shh), however, little is known about neuron-specific regulation of Shh transport and secretion. To study this process, we investigated the subcellular distribution of Shh in primary neurons and differentiated cells of a neuroendocrine cell line by fluorescence microscopy and biochemical fractionation. In retinal ganglion cells, endogenous Shh was distributed as intra- and extracellular puncta at the soma, dendrites, axons and neurite terminals. Shh(+) puncta move bidirectionally and colocalize with markers of synaptic vesicles (SVs) and dense core granules. Lipid modification and proteolysis were required for Shh sorting to SVs and cell surface association. Finally, consistent with its association with regulated secretory vesicles, Shh secretion could be induced under depolarizing conditions. Taken together, these observations suggest that long-range Shh transport and signalling in neurons involves trafficking to the regulated secretory pathway and cell surface accumulation of Shh on axons and suggests a link between neuronal activity and Shh release.