Ruijing Xiao

The invasion of tobacco mosaic virus RNA induces endoplasmic reticulum stress-related autophagy in HeLa cells.

The ability of human cells to defend against viruses originating from distant species has long been ignored. Owing to the pressure of natural evolution and human exploration, some of these viruses may be able to invade human beings. If their ‘fresh’ host had no defences, the viruses could cause a serious pandemic, as seen with HIV, SARS (severe acute respiratory syndrome) and avian influenza virus that originated from chimpanzees, the common palm civet and birds, respectively. It is unknown whether the human immune system could tolerate invasion with a plant virus. To model such an alien virus invasion, we chose TMV (tobacco mosaic virus) and used human epithelial carcinoma cells (HeLa cells) as its ‘fresh’ host. We established a reliable system for transfecting TMV-RNA into HeLa cells and found that TMV-RNA triggered autophagy in HeLa cells as shown by the appearance of autophagic vacuoles, the conversion of LC3-I (light chain protein 3-I) to LC3-II, the up-regulated expression of Beclin1 and the accumulation of TMV protein on autophagosomal membranes. We observed suspected TMV virions in HeLa cells by TEM (transmission electron microscopy). Furthermore, we found that TMV-RNA was translated into CP (coat protein) in the ER (endoplasmic reticulum) and that TMV-positive RNA translocated from the cytoplasm to the nucleolus. Finally, we detected greatly increased expression of GRP78 (78 kDa glucose-regulated protein), a typical marker of ERS (ER stress) and found that the formation of autophagosomes was closely related to the expanded ER membrane. Taken together, our data indicate that HeLa cells used ERS and ERS-related autophagy to defend against TMV-RNA.

Uncovering the roles of long non-coding RNAs in cancer stem cells

Cancer has been a major public health problem that has threatened human life worldwide throughout history. The main causes that contribute to the poor prognosis of cancer are metastasis and recurrence. Cancer stem cells are a group of tumor cells that possess self-renewal and differentiation ability, which is a vital cause of cancer metastasis and recurrence. Long non-coding RNAs refer to a class of RNAs that are longer than 200xa0nt and have no potential to code proteins, some of which can be specifically expressed in different tissues and different tumors. Long non-coding RNAs have great biological significance in the occurrence and progression of cancers. However, how long non-coding RNAs interact with cancer stem cells and then affect cancer metastasis and recurrence is not yet clear. Therefore, this review aims to summarize recent studies that focus on how long non-coding RNAs impact tumor occurrence and progression by affecting cancer stem cell self-renewal and differentiation in liver cancer, prostate cancer, breast cancer, and glioma.

EBV-Induced Human CD8(+) NKT Cells Synergise CD4(+) NKT Cells Suppressing EBV-Associated Tumours upon Induction of Th1-Bias

CD8+ natural killer T (NKT) cells from EBV-associated tumour patients are quantitatively and functionally impaired. EBV-induced CD8+ NKT cells drive syngeneic T cells into a Th1-bias response to suppress EBV-associated malignancies. IL-4-biased CD4+ NKT cells do not affect either syngeneic T cell cytotoxicity or Th cytokine secretion. Circulating mDC1 cells from patients with EBV-associated malignancies impair the production of IFN-γ by CD8+ NKT cells. In this study, we have established a human-thymus-SCID chimaera model to further investigate the underlying mechanism of EBV-induced CD8+ NKT cells in suppressing EBV-associated malignancies. In the human-thymus-SCID chimera, EBV-induced CD8+ NKT cells suppress EBV-associated malignancies in a manner dependent on the Th1-bias response and syngeneic CD3+ T cells. However, adoptive transfer with CD4+ NKT cells alone inhibits T cell immunity. Interestingly, CD4+ NKT cells themselves secrete high levels of IL-2, enhancing the persistence of adoptively transferred CD8+ NKT cells and T cells, thereby leading to a more pronounced T cell anti-tumour response in chimaeras co-transferred with CD4+ CD8+ NKT cells. Thus, immune reconstitution with EBV-induced CD4+ and CD8+ NKT cells synergistically enhances T cell tumour immunity, providing a potential prophylactic and therapeutic treatment for EBV-associated malignancies.

Anti-CCL25 Antibody Prolongs Skin Allograft Survival by Blocking CCR9 Expression and Impairing Splenic T-Cell Function

Chemokines, by virtue of their ability to recruit immune cells into allografts, play critical roles in acute transplantation rejection. CCR9 and its ligand, CCL25, is one of the key regulators of thymocyte migration and maturation in normal and inflammatory conditions. Moreover, several studies have revealed that high expression of CCR9 and CCL25 participated in many kinds of diseases. However, the role of CCR9 in allograft rejection is still unclear. In this study, we established a murine skin transplantation model of acute rejection. Our findings showed that the proportion of CCR9-expressing T cells was significantly increased in the spleen of allotransplanted mice compared with syngeneic transplantation. Furthermore, expression of CCL25 in allograft was similarly increased. Neutralization of CCL25 by intravenous injection of anti-CCL25 monoclonal antibody significantly prolonged skin allograft survival, decreased the number of infiltrating cells, and simultaneously suppressed the chemotactic ability and the proliferation of the splenic T cells in response to allogeneic antigens. Finally, blockade of CCL25 also diminished the secretion of IFN-γ by splenic T cells. These studies indicated that CCR9/CCL25 was involved in acute transplantation rejection and anti-CCL25 strategies might be useful in preventing acute rejection.

Expression profile of human immune-responsive gene 1 and generation and characterization of polyclonal antiserum

Murine immune-responsive gene 1 (IRG1) plays significant roles in embryonic implantation and neurodegeneration. The expression pattern of the human IRG1 gene, however, has not yet been established, and the predicted gene sequence has been revised several times according to computed expressed sequence tags (ESTs). To determine the human IRG1 gene expression profile, human fetal tissue samples, peripheral blood mononuclear cells (PBMCs) from normal healthy subjects, and the human leukemia cell lines THP-1 and K-562 challenged with lipopolysaccharide (LPS) were subjected to RT-PCR using degenerate primers. The results indicated that the IRG1 gene is differentially expressed in human fetal PBMCs and LPS-stimulated adult PBMCs. The amplified gene fragment was cloned into the pET32a(+) vector and fusion-expressed with a His-tag in a prokaryotic system. After affinity chromatography, human IRG1h fusion proteins were isolated by SDS-PAGE and identified by mass spectrometric analysis for use as an immunogen to immunize rabbits. The titer and specificity of the purified rabbit antiserum were sufficient to measure human IRG1 gene expression in various tissues and cultures. This purified polyclonal antiserum will allow us to initiate studies to elucidate the biological roles of the human IRG1 gene.

Wnt5a and CCL25 promote adult T-cell acute lymphoblastic leukemia cell migration, invasion and metastasis

Adult T-cell acute lymphoblastic leukemia (T-ALL) is a refractory leukemia. We previously showed that CCL25/CCR9 promotes T-ALL metastasis. In the present study, we assessed the effects of CCL25 on Wnt expression and the effects of Wnt5a and CCL25 on PI3K/Akt and RhoA activation. Transwell assays and mouse xenograft experiments were utilized to assess the effects of Wnt5a and CCL25 on MOLT4 cell invasion, migration and metastasis. The effects of Wnt5a on MOLT4 cell actin polarization and pseudopodium formation were examined using laser scanning confocal microscopy and scanning electron microscopy. CCL25 induced Wnt5a expression in MOLT4 cells by promoting protein kinase C (PKC) expression and activation. Wnt5a promoted MOLT4 cell migration, invasion, actin polarization, and lamellipodium and filopodia formation via PI3K/Akt-RhoA pathway activation. These effects were rescued by PI3K/Akt or RhoA knockdown or inhibition. Additionally, Wnt5a in cooperation with CCL25 promoted MOLT4 cell mouse liver metastasis and stimulated RhoA activation. These results show that CCL25/CCR9 upregulates Wnt5a by promoting PKC expression and activation in MOLT4 cells. This in turn promotes cell migration and invasion via PI3K/Akt-RhoA signaling, enhancing cell polarization and pseudopodium formation. These findings indicate that the PI3K/Akt-RhoA pathway is likely responsible for Wnt5a-induced adult T-ALL cell migration and invasion.

High dose lipopolysaccharide triggers polarization of mouse thymic Th17 cells in vitro in the presence of mature dendritic cells

Lipopolysaccharide (LPS) plays an important role in the activation of innate immune cells, leading to secretion of proinflammatory factors and bridging the adaptive immune system. Exposing total mouse thymic cells culture to LPS induced a unique expression profile of cytokines (IL-17A, IL-17F, and IL-22) and the essential ROR-γt master transcription factor, which suggested a preferential differentiation of thymocytes towards the Th17 cell phenotype. Th17-polarizing molecules (IL-23, IL-23R, IL-6, and TGF-β) and IL-17A(+)CD4(+) thymocytes were also specifically produced by the in vitro LPS-stimulation of thymic cells. Furthermore, both the expression of Th17 differentiation-related molecules and the frequency of Th17 cells were significantly up-regulated with increasing doses of LPS, as evidenced by quantitative RT-PCR and flow cytometric analysis, respectively. The expressions and frequency reached maximum levels when LPS exposure had been maintained at an extremely high concentration (100 μg/mL) for 48 h. On the other hand, depletion of thymic dendritic cells (DCs) blocked the LPS-induced polarization of thymus-derived Th17 cell lineage. Addition of bone marrow-derived DCs (BMDCs) to the purified immature CD4(+) CD62L(low) thymocytes culture recovered the switch towards Th17 cells, which synergistically prompted the cytotoxic activity of CD8(+) T cells. Taken together, our data indicates that high doses of LPS can promote the differentiation of mouse thymus-derived Th17 cells by a mechanism involving components associated with mature DCs.

NHE1 has a notable role in metastasis and drug resistance of T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) represents a spectrum of hematological malignancies that affect human health. Metastasis and chemotherapeutic drug resistance are the primary causes of mortality in patients with T-ALL. Sodium-hydrogen antiporter 1 (NHE1) is established to serve a role in metastasis and drug resistance in numerous types of cancer; however, the function of NHE1 in T-ALL remains to be elucidated. Previously, the C-C-motif chemokine ligand 25 (CCL25) was identified to be involved in metastasis and drug resistance in the MOLT4 T-ALL cell line, as was the ezrin protein. The present study investigated the role of NHE1 in the metastasis of T-ALL using a Transwell assay and scanning electron microscopy, using MOLT4 cells as a model. The association between NHE1 and ezrin was assessed using laser scanning confocal microscopy. The effect of NHE1 on resistance to the chemotherapy drug doxorubicin (DOX) was also investigated using a cell viability and cytotoxicity assay. Expression of NHE1 increased following treatment with CCL25, accompanied by morphological changes in MOLT4 cells and the co-localization of NHE1 with ezrin. In addition, wild-type MOLT4 cells exhibited an increased polarization ability compared with NHE1- or ezrin-silenced cells. NHE1- or ezrin-silenced cells exhibited higher sensitivity to DOX compared with wild-type MOLT4 cells. In conclusion, the increased expression or activity of NHE1 may potentially be a poor prognostic indicator for human T-ALL.

Synergistic effects of baicalein with gemcitabine or docetaxel on the proliferation, migration and apoptosis of pancreatic cancer cells

Baicalein, a type of flavonoids extracted from Scutellaria baicalensis Georgi, has been reported to be a very promising drug for pancreatic cancer. However, it is unclear whether combination of baicalein with gemcitabine or docetaxel is synergistic to the treatment for pancreatic cancer (PC). We investigated the combinational effects of baicalein with gemcitabine or docetaxel on proliferation, cell cycle, migration and apoptosis of human PC cells. Administration of baicalein alone significantly inhibit the proliferation of PC cells. Notably, when it is combined with gemcitabine or docetaxel, combination index (CI) values calculated by Calcusyn software are smaller than 1, indicating the synergism of baicalein with gemcitabine or docetaxel for the treatment of PC cells. Consistently, EdU assay showed that administration of baicalein significantly enhanced the capacity of gemicitabine to inhibit proliferation of PC cells. Cell cycle analysis showed that high-concentration of baicalein was able to arrest PC cells in the Sxa0phase. Furthermore, low concentration of baicalein in combination with either gemcitabine or docetaxel exhibited strong suppression on the migration of PC cells. A further study using transmission electron microscope (TEM), DAPI staining and western blot showed that baicalein induced-apoptosis of PC cells might be via caspase-3/PARP signaling pathway. Notably, combination treatment was able to induce more severe cell apoptosis of PC cells. In conclusion, baicalein exhibited synergistic effects with gemcitabine or docetaxel on the treatment of PC cells.

Bioinformatic analysis of prognostic value of ZW10 interacting protein in lung cancer

Background ZWINT is a crucial component of the mitotic checkpoint. However, its possible role in lung cancer is unclear. In this study, we determined its correlation with lung cancer. Methods Real-time PCR and immunohistochemistry (IHC) were used to determine 40 collected clinical lung cancer samples. Chi-square test was used to examine possible correlations between ZWINT expression and clinicopathological factors. The prognostic significance of mRNA expression of ZWINT in lung cancer was evaluated using the Kaplan–Meier plotter. Univariate and multivariate Cox proportional hazards regression analysis were performed to determine whether ZWINT is an independent risk factor for overall survival (OS) and disease-free survival (DFS) of lung cancer patients. Additionally, STRING database was used to analyze protein-protein interactions. Results In this study, we screened 13 GSE datasets and detected that ZWINT is highly expressed in multiple carcinomas including lung, melanoma, prostate, nasopharyngeal, gastric, pancreatic, colon, esophageal, ovarian, renal, breast and liver cancer. Real-time PCR and IHC results of collected clinical lung cancer samples confirmed that ZWINT is highly expressed in tumor tissues compared with adjacent non-tumor tissues. Additionally, high expression of ZWINT might predict poor OS and DFS in lung cancer patients. Moreover, disease stage and expression level of ZWINT were correlated with recurrence-free survival and OS in lung cancer. Analysis of protein-protein interaction based on STRING database gained 8 top genes which could interact with ZWINT, including PMF1, MIS12, DSN1, ZW10, BUB1, BUB1B, CASC5, NDC80, NSL1 and NUF2. Conclusion ZWINT is aberrantly highly expressed in lung tumor tissues and might be involved in the pathogenesis of lung cancer.