Tumor growth and metastasis suppression by Glipr1 gene-modified macrophages in a metastatic prostate cancer model

Glioma pathogenesis-related protein 1 performs dual functions in tumor cells

Glioma pathogenesis-related protein 1 (GLIPR1) was identified as an oncoprotein in some cancer types including gliomas, breast cancers, melanoma cancers, and Wilms tumors, but as a tumor suppressor in some other types of cancers, such as prostate cancers, lung cancers, bladder cancers, and thyroid cancers. In gliomas, GLIPR1 promotes the migration and invasion of glioma cells by interaction with the actin polymerization regulator Neural Wiskott-Aldrich syndrome protein (N-WASP) and then abolishes the negative effects of Heterogeneous nuclear ribonuclear protein K (hnRNPK). In prostate cancers, high levels of GLIPR1 induce apoptosis and destruction of oncoproteins. In lung cancers, overexpression of GLIPR1 inhibits the growth of lung cancer cells partially through inhibiting the V-ErbB avian erythroblastic leukemia viral oncogene homolog3 (ErbB3) pathway. However, the mechanisms that GLIPR1 performs its function in other tumors still remain unclear. The tumor suppressing role of GLIPR1 has been explored to the cancer treatment. The adenoviral vector-mediated Glipr1 (AdGlipr1) gene therapy and the GLIPR1-transmembrane domain deleted (GLIPR1-ΔTM) protein therapy both showed antitumor activities and stimulated immune response in prostate cancers. Whether GLPIR1 can be used to treat other tumors is an important topic to be explored. Among which, whether GLPIR1 can be used to treat lung cancer by atomizing inhalation is the key topic we care about. If it does, this therapy has a wide application prospect and is a great progression in lung cancer treatment.

Yeast-mediated mRNA delivery polarizes immuno-suppressive macrophages towards an immuno-stimulatory phenotype

Macrophages have increasingly gained interest as a therapeutic target since they represent an integral component of the tumor microenvironment. In fact, M2 macrophage accumulation in solid tumors is associated with poor prognosis and therapy failure. Therefore, reprogramming M2 macrophages towards an M1 phenotype with anti-tumor activity by gene therapy represents a promising therapeutic approach. Herein, we describe recombinant Saccharomyces cerevisiae as a novel gene delivery vehicle for primary human macrophages. Opsonized S. cerevisiae was taken up efficiently by M2 macrophages and initiated the expression of pro-inflammatory cytokines. Recombinant yeast delivered functional nucleic acids to macrophages, especially when constitutively biosynthesized mRNA was used as cargo. Interestingly, expression of the protein encoded for by the delivered nucleic acid was higher in M2 cells when compared to M1 macrophages. Finally, the delivery of mRNA coding for the pro-inflammatory regulators MYD88 and TNF to M2 macrophages induced a prolonged upregulation of pro-inflammatory and cytotoxic cytokines in these cells, suggesting their successful re-education towards an anti-tumor M1 phenotype. Our results suggest the use of yeast-based gene delivery as a promising approach for the treatment of pathologic conditions that may benefit from the presence of M1-polarized macrophages, such as cancer.

GLIPR1-ΔTM synergizes with docetaxel in cell death and suppresses resistance to docetaxel in prostate cancer cells

Background

Docetaxel is the first chemotherapy agent approved for treatment of metastatic castration-resistant prostate cancer (mCRPC). The limited survival benefit associated with the quick emergence of resistance and systemic toxicity diminished its efficacy. JNK-mediated apoptosis is one of the mechanisms of docetaxel activity whereas ERK1/2-c-Myc-CXCR4 signaling is implicated in the development of resistance and induction of migration. The aim of this study was to evaluate the hypothesis that the combination treatment with docetaxel and GLIPR1-ΔTM will synergistically induce greater cell death and inhibit the emergence of resistance and development of metastatic potential in prostate cancer (PCa) cells.

Methods

The synergistic effects of the docetaxel and GLIPR1-ΔTM were evaluated with DNA fragmentation, DAPI staining and MTS using paired t-test and isobologram study. The effects of the drugs on JNK and ERK1/2-c-Myc-CXCR4 signaling were evaluated with Western blot, DNA fragmentation, and MTS assays using the JNK inhibitor SP600125, and CXCR4 siRNA. The results of docetaxel and GLIPR1-ΔTM combination on migration were examined with scratch assay using the CXCR4 inhibitor AMD3100 while our hypothesis was examined in vivo using VCaP orthotopic xenograft model.

Results

We found that GLIPR1-ΔΤΜ synergized with docetaxel to induce apoptosis in VCaP and PC-3 PCa cells through induction of JNK signaling and concomitant inhibition of ERK1/2-c-Myc-CXCR4 signaling. We showed that JNK activation mediates the apoptotic effects of the drug combination and that CXCR4 knockdown increases its efficacy. We also found that the addition of GLIPR1-ΔΤΜ to docetaxel decreases the migration of VCaP and PC-3 cells. The combination treatment with docetaxel and GLIPR1-ΔTM inhibited tumor growth and decreased metastatic potential in VCaP xenografts more than single agents did.

Conclusions

Our data suggested that addition of GLIPR1-ΔTM treatment in PCa cells increases the efficacy of docetaxel and may inhibit the emergence of drug resistance; potentially permitting a decrease of docetaxel dose for patients with mCRPC eliminating its systemic toxicities.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0395-0) contains supplementary material, which is available to authorized users.

Macrophage-targeted delivery systems for nucleic acid therapy of inflammatory diseases

Inflammation is an immune response that marks several pathophysiological conditions in our body. Though adaptive immune cells play a major role in the progression of the disease, components of innate immune system, mainly monocytes and macrophages play the central role in onset of inflammation. Tissue-associated macrophages are widely distributed in the body showing tremendous anatomical and functional diversity and are actively involved in maintaining the homeostasis. They exhibit different phenotypes depending on their residing tissue microenvironment and the two major functional phenotypes are classically activated M1 phenotype showing pro-inflammatory characteristics and alternatively activated M2 phenotype demonstrating anti-inflammatory nature. Several cytokines, chemokines and other regulatory mediators delicately govern the balance of the two phenotypes in a tissue. This balance, however, is subverted during infection, injury or autoimmune response leading to increased population of M1 phenotype and subsequent chronic inflammatory disease states. This review underlines the role of macrophages in inflammatory diseases with an insight into potential molecular targets for nucleic acid therapy. Finally, some recent nanotechnology-based approaches to devise macrophage-specific targeted therapy have been highlighted.

Systemic GLIPR1-ΔTM protein as a novel therapeutic approach for prostate cancer

GLIPR1 is a p53 target gene known to be downregulated in prostate cancer, and increased endogenous GLIPR1 expression has been associated with increased production of reactive oxygen species, increased apoptosis, decreased c-Myc protein levels and increased cell cycle arrest. Recently, we found that upregulation of GLIPR1 in prostate cancer cells increases mitotic catastrophe through interaction with heat shock cognate protein 70 (Hsc70) and downregulation of Aurora kinase A and TPX2. In this study, we evaluated the mechanisms of recombinant GLIPR1 protein (glioma pathogenesis-related protein 1-transmembrane domain deleted [GLIPR1-ΔTM]) uptake by prostate cancer cells and the efficacy of systemic GLIPR1-ΔTM administration in a prostate cancer xenograft mouse model. GLIPR1-ΔTM was selectively internalized by prostate cancer cells, leading to increased apoptosis through reactive oxygen species production and to decreased c-Myc protein levels. Interestingly, GLIPR1-ΔTM was internalized through clathrin-mediated endocytosis in association with Hsc70. Systemic administration of GLIPR1-ΔTM significantly inhibited VCaP xenograft growth. GLIPR1-ΔTM showed no evidence of toxicity following elimination from mouse models 8 hr after injection. Our results demonstrate that GLIPR1-ΔTM is selectively endocytosed by prostate cancer cells, leading to increased reactive oxygen species production and apoptosis, and that systemic GLIPR1-ΔTM significantly inhibits growth of VCaP xenografts without substantial toxicity.

Combined therapeutic effects of adenoviral vector-mediated GLIPR1 gene therapy and radiotherapy in prostate and bladder cancer models

OBJECTIVES

The objectives of this study are to explore the potential benefits of combining AdGlipr1 (or AdGLIPR1) gene therapy with radiotherapy using subcutaneous prostate and bladder cancer models.

MATERIALS AND METHODS

Combination adenoviral vector-mediated gene therapy and radiotherapy were applied to 178-2 BMA and TSU-Pr1 cells in vitro and colony formation and apoptosis were analyzed. In addition, combination therapies were administered to mice bearing subcutaneous 178-2 BMA and TSU-Pr1 tumors, and tumor growth suppression and survival extension were compared with the monotherapies (AdGlipr1/AdGLIPR1 and radiotherapy) or control vector Adv/CMV/βgal, as well as single-cycle treatment with 2-cycle treatment.

RESULTS

Combination treatment significantly suppressed colony formation and increased apoptosis in vitro. In vivo, combination therapy produced significant 178-2 BMA and TSU-Pr1 tumor growth suppression and survival extension compared with the monotherapies or the control. Further tumor growth suppression and survival extension were observed after 2 cycles of the combination treatment.

CONCLUSIONS

Combining AdGlipr1 (AdGLIPR1) with radiotherapy may achieve additive or synergistic tumor control in selected prostate and bladder tumors, and additional therapeutic effects may result with repeated treatment cycles.