Lung regeneration: diverse cell types and the therapeutic potential.

Lung tissue has a certain regenerative ability and triggers repair procedures after injury. Under controllable conditions, lung tissue can restore normal structure and function. Disruptions in this process can lead to respiratory system failure and even death, causing substantial medical burden. The main types of respiratory diseases are chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and acute respiratory distress syndrome (ARDS). Multiple cells, such as lung epithelial cells, endothelial cells, fibroblasts, and immune cells, are involved in regulating the repair process after lung injury. Although the mechanism that regulates the process of lung repair has not been fully elucidated, clinical trials targeting different cells and signaling pathways have achieved some therapeutic effects in different respiratory diseases. In this review, we provide an overview of the cell type involved in the process of lung regeneration and repair, research models, and summarize molecular mechanisms involved in the regulation of lung regeneration and fibrosis. Moreover, we discuss the current clinical trials of stem cell therapy and pharmacological strategies for COPD, IPF, and ARDS treatment. This review provides a reference for further research on the molecular and cellular mechanisms of lung regeneration, drug development, and clinical trials.

Eradication of large established tumors by drug-loaded bacterial particles via a neutrophil-mediated mechanism.

The treatment of large established tumors remains a significant challenge and is generally hampered by poor drug penetration and intrinsic drug resistance of tumor cells in the central tumor region. In the present study, we developed bacterial particles (BactPs) to deliver chemotherapeutics into the tumor mass by hijacking neutrophils as natural cell-based carriers. BactPs loaded with doxorubicin, 5-fluorosuracil, or paclitaxel induced significantly greater tumor regression than unconjugated drugs. This effect was mediated by the ability of BactPs to incorporate chemotherapeutics and serve as vascular disrupting agents that trigger innate host responses and recruit phagocytic neutrophils. Vascular disruption resulted in extensive cell death in the central areas of the tumor mass. Recruited neutrophils acted as natural cellular carriers to deliver engulfed BactPs, which ensured drug delivery into the tumor mass and cytotoxic effects in areas that are normally inaccessible to traditional chemotherapy. Thus, BactPs eradicate large established tumors by functioning as vascular disrupters and natural drug carriers for neutrophil-mediated chemotherapy.

Bacterial particles retard tumor growth as a novel vascular disrupting agent.

Due to hypoxia and poor circulation in the tumor interior, malignant cells in solid tumors are resistant to traditional therapies. In the present study, we reported that bacterial particles (BactPs) functioned effectively in retarding tumor growth as a novel vascular disrupting agent. The BactPs were inactivated intact bacteria. Intravenous administration of BactPs extensively disrupted vessels in the tumor interior, but not in normal organs, and resulted in tumor hemorrhage and necrosis in six hours. We revealed that the extensive disruption of tumor vasculature was due to drastic changes in the inflammatory factors in mice sera and the tumor microenvironments, indicating the critical role of the host immune response to the BactPs. Furthermore, we showed that a combination of six inflammatory cytokines was capable of inducing tumor hemorrhage and necrosis, similar to the effects of the BactPs. Together, these results suggest that BactPs are a novel kind of tumor vascular disruptor with a promising potential for solid tumor treatment.

Long noncoding RNA GAS5 does not regulate HBV replication.

Hepatitis B virus (HBV) infection remains a severe health burden worldwide. Emerging long noncoding RNAs (lncRNAs) are hijacked to enhance virus replication or employed by the host to stimulate immune responses to clear the virus. LncRNA growth arrest-specific transcript 5 (GAS5) can regulate RNA virus by suppressing the replication of both hepatitis C virus and human immunodeficiency virus. In this study, we explored the changes of HBV replication by overexpressing or knocking down GAS5 in HepAD38 cell and HepG2 cell transfected with pHBV1.2. We found HBV can induce the expression of GAS5. However, GAS5 had no effect on extracellular HBsAg and HBeAg, nor intracellular HBV RNA and HBV DNA. In addition, GAS5 possessed similar expression levels between stable HBV-producing cell lines and hepatoma cell lines. Furthermore, GAS5 showed no difference between healthy subjects and patients with chronic HBV in multiple GEO microarray data sets by GEO2R analysis. Taken together these results, GAS5 does not modulate the replication of HBV but it inhibits cell proliferation in HepAD38. This provides insights into the possible roles of GAS5 in HBV infection.

Integrated microarray meta-analysis identifies miRNA-27a as an oncogene in ovarian cancer by inhibiting FOXO1.

AIMS: Survival of ovarian cancer patients is generally poor, partly because most of them are already at an advanced stage when diagnosed. The purpose of this study was to screen prognostic miRNAs for ovarian cancer, and to explore the underlying mechanisms. MAIN METHODS: Integrated meta-analysis of miRNA microarrays retrieved from public repositories was employed to identify clinically significant miRNAs involved in ovarian cancer. Targets of candidate miRNA were predicted using four online databases, and validated with dual luciferase assay. Loss and gain of function were performed to investigate the role of miR27a in the growth of ovarian cancer cell lines. KEY FINDINGS: Based on cross-validation results in multiple datasets, we recognized hsa-miR-27a as an oncogenic molecular and a prognostic factor for ovarian cancer patients. Dual luciferase assay indicated tumor suppressor FOXO1 was a direct target of miR-27a. In addition, hsa-miR-27a could stimulate SKOV3 and A2780 cell proliferation and migration by regulating the expression of FOXO1. SIGNIFICANCE: In summary, our results indicate that miR-27a can promote progression of ovarian cancer by mediating FOXO1. To our knowledge, this is the first study focusing on the role of miR-27a/FOXO1 axis using the microarray meta-analysis in ovarian cancer. Furthermore, inhibiting miR-27a expression may be a new strategy for the treatment of ovarian cancer.

Targeting the vascular and perivascular niches as a regenerative therapy for lung and liver fibrosis.

The regenerative capacity of lung and liver is sometimes impaired by chronic or overwhelming injury. Orthotopic transplantation of parenchymal stem cells to damaged organs might reinstate their self-repair ability. However, parenchymal cell engraftment is frequently hampered by the microenvironment in diseased recipient organs. We show that targeting both the vascular niche and perivascular fibroblasts establishes "hospitable soil" to foster the incorporation of "seed," in this case, the engraftment of parenchymal cells in injured organs. Specifically, ectopic induction of endothelial cell (EC)-expressed paracrine/angiocrine hepatocyte growth factor (HGF) and inhibition of perivascular NOX4 [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase 4] synergistically enabled reconstitution of mouse and human parenchymal cells in damaged organs. Reciprocally, genetic knockout of Hgf in mouse ECs (HgfiΔEC/iΔEC) aberrantly up-regulated perivascular NOX4 during liver and lung regeneration. Dysregulated HGF and NOX4 pathways subverted the function of vascular and perivascular cells from an epithelially inductive niche to a microenvironment that inhibited parenchymal reconstitution. Perivascular NOX4 induction in HgfiΔEC/iΔEC mice recapitulated the phenotype of human and mouse liver and lung fibrosis. Consequently, EC-directed HGF and NOX4 inhibitor GKT137831 stimulated regenerative integration of mouse and human parenchymal cells in chronically injured lung and liver. Our data suggest that targeting dysfunctional perivascular and vascular cells in diseased organs can bypass fibrosis and enable reparative cell engraftment to reinstate lung and liver regeneration.

Mitochondrial C11orf83 is a potent Antiviral Protein Independent of interferon production.

Mitochondria have a central position in innate immune response via the adaptor protein MAVS in mitochondrial outer membrane to limit viral replication by inducing interferon production. Here, we reported that C11orf83, a component of complex III of electronic transfer chain in mitochondrial inner membrane, was a potent antiviral protein independent of interferon production. C11orf83 expression significantly increased in response to viral infection, and endows cells with stronger capability of inhibiting viral replication. Deletion of C11orf83 permits viral replication easier and cells were more vulnerable to viral killing. These effects mainly were mediated by triggering OAS3-RNase L system. C11orf83 overexpression induced higher transcription of OAS3, and knockdown either OAS3 or RNase L impaired the antiviral capability of C11orf83. Interestingly, the signaling from C11orf83 to OAS3-RNase L was independent of interferon production. Thus, our findings suggested a new antiviral mechanism by bridging cell metabolic machinery component with antiviral effectors.

Long Noncoding RNA LINC00092 Acts in Cancer-Associated Fibroblasts to Drive Glycolysis and Progression of Ovarian Cancer.

The majority of patients with epithelial ovarian cancer are diagnosed at a late stage when the peritoneal metastases exist; however, there is little knowledge of the metastatic process in this disease setting. In this study, we report the identification of the long noncoding RNA LINC00092 as a nodal driver of metastatic progression mediated by cancer-associated fibroblasts (CAF). Prometastatic properties of CAFs in vitro and in vivo were found to associate with elevated expression of the chemokine CXCL14. In clinical specimens, elevated levels of CXCL14 in CAFs also correlated with poor prognosis. Notably, CXCL14-high CAFs mediated upregulation of LINC00092 in ovarian cancer cells, the levels of which also correlated with poor prognosis in patients. Mechanistic studies showed that LINC00092 bound a glycolytic enzyme, the fructose-2,6-biphosphatase PFKFB2, thereby promoting metastasis by altering glycolysis and sustaining the local supportive function of CAFs. Overall, our study uncovered a positive feedback loop in the metabolism of CXCL14-positive CAFs and ovarian cancer cells that is critical for metastatic progression. Cancer Res; 77(6); 1369-82. ©2017 AACR.

Endothelial Cords Promote Tumor Initial Growth prior to Vascular Function through a Paracrine Mechanism.

The angiogenic switch is an important oncogenic step that determines whether microtumors remain dormant or progresses further. It has been generally perceived that the primary function of this tumorgenic event is to supply oxygen and nutrients through blood circulation. Using in vivo imaging of zebrafish and mouse tumor models, we showed that endothelial cords aggressively penetrated into microtumors and remained non-circulatory for several days before undergoing vascular blood perfusion. Unexpectedly, we found that initial tumor growth in both models was significantly reduced if endothelial cords were removed by blocking VEGF-VEGFR2 signaling or using a vascular deficient zebrafish mutant. It was further shown that soluble factors including IL-8, secreted by endothelial cells (ECs) were responsible for stimulating tumor cells proliferation. These findings establish that tumor angiogenesis play a much earlier and broader role in promoting tumor growth, which is independent of vascular circulation. Understanding this novel mechanism of angiogenic tumor progression offers new entry points for cancer therapeutics.