Root-associated bacteria strengthen their community stability against disturbance of antibiotics on structure and functions.

Antibiotics affect bacterial community structure and functions in soil. However, the response and adaptation of root-associated bacterial communities to antibiotic stress remains poorly understood. Here, rhizobox experiments were conducted with maize (Zea mays L.) upon exposure to antibiotics ciprofloxacin or tetracycline. High-throughput sequencing analysis of bacterial community and quantitative PCR analysis of nitrogen cycling genes show that ciprofloxacin and tetracycline significantly shift bacterial community structure in bulk soil, whereas plant host may mitigate the disturbances of antibiotics on bacterial communities in root-associated niches (i.e., rhizosphere and rhizoplane) through the community stabilization. Deterministic assembly, microbial interaction, and keystone species (e.g., Rhizobium and Massilia) of root-associated bacterial communities benefit the community stability compared with those in bulk soil. Meanwhile, the rhizosphere increases antibiotic dissipation, potentially reducing the impacts of antibiotics on root-associated bacterial communities. Furthermore, rhizospheric effects deriving from root exudates alleviate the impacts of antibiotics on the nitrogen cycle (i.e., nitrification, organic nitrogen conversion and denitrification) as confirmed by functional gene quantification, which is largely attributed to the bacterial community stability in rhizosphere. The present study enhances the understanding on the response and adaptation of root-associated bacterial community to antibiotic pollution.

A linear and circular dual-conformation noncoding RNA involved in oxidative stress tolerance in Bacillus altitudinis.

Circular RNAs have been extensively studied in eukaryotes, but their presence and/or biological functionality in bacteria are unclear. Here, we show that a regulatory noncoding RNA (DucS) exists in both linear and circular conformation in Bacillus altitudinis. The linear forms promote B. altitudinis tolerance to H2O2 stress, partly through increased translation of a stress-responsive gene, htrA. The 3' end sequences of the linear forms are crucial for RNA circularization, and formation of circular forms can decrease the levels of the regulatory linear cognates. Bioinformatic analysis of available RNA-seq datasets from 30 bacterial species revealed multiple circular RNA candidates, distinct from DucS, for all the examined species. Experiments testing for the presence of selected circular RNA candidates in four species successfully validated 7 out of 9 candidates from B. altitudinis and 4 out of 5 candidates from Bacillus paralicheniformis; However, none of the candidates tested for Bacillus subtilis and Escherichia coli were detected. Our work identifies a dual-conformation regulatory RNA in B. altitutidinis, and indicates that circular RNAs exist in diverse bacteria. However, circularization of specific RNAs does not seem to be conserved across species, and the circularization mechanisms and biological functionality of the circular forms remain unclear.

Isolation and characterization of a novel goose ovaritis-associated cluster 3 Tembusu virus.

Tembusu virus (TMUV) is a member of the genus Flavivirus in the family Flaviviridae. Currently, TMUV was classified into 4 distinct clusters, with cluster 2 strains widely distributed in duck and goose populations in Asia, causing significant economic losses to the producing industries. In this study, a novel TMUV strain TMUV/goose/CHN/2019/HNU-NX2 (HNU-NX2-2019) was isolated and characterized from geese with ovaritis from Hunan province, China. Phylogenetic analyses of genome and the E gene indicated the present TMUV could be grouped into the newly defined TMUV cluster 3. The genome of HNU-NX2-2019 showed the highest identities of 98.1% to 98.2% to the cluster 3 TMUVs newly identified in 2020 and 2021 from chickens with a severe egg-drop syndrome from Guangdong, Guangxi and Shandong provinces of China, which were all showing a close relation to a mosquito-origin TMUV (KT607936) identified in 2012. Further experiments confirmed HNU-NX2-2019 could grow well in chicken fibroblast cell line DF-1 and in SPF chicken embryos, with titers varied from 107.3 to 108.8 viral genomic copies per mL in the culture solutions. A pilot virus challenge study in 3-day-old chicks demonstrated that this virus could efficiently infect chicks with virus distributed in the brains, small intestines and other visceral organs, with titers varied from 105.4 to 106.7viral genomic copies per gram of the tissues. Furthermore, HNU-NX2-2019 can induce specific antibody in ducklings but with no obvious disease and virus shedding, and on necropsy no TMUV was detected in the tissues in the present study. This is the first report to identify a novel cluster 3 TUMV from goose, and further demonstrated this goose TMUV strain could infect chicken efficiently but not in ducklings under the present experimental conditions, which highlighted intensive attentions may be paid to this novel mosquito-origin cluster 3 TMUV.

Id4 Suppresses the Growth and Invasion of Colorectal Cancer HCT116 Cells through CK18-Related Inhibition of AKT and EMT Signaling.

Id4 is one of the inhibitors of DNA-binding proteins (Id) and involved in the pathogenesis of numerous cancers. The specific mechanism underlying the Id4-mediated regulation of proliferation, invasion, and metastasis of colorectal cancer (CRC) cells is still largely unclear. In the present study, results showed CRC cells had a lower baseline Id4 expression than normal intestinal epithelial NCM460 cells. In order to explore the role of Id4 in the tumorigenicity, CRC HCT116 cells with stable Id4 expression were used, and results showed Id4 overexpression arrested the cell cycle at the G0/G1 phase, inhibited the cell proliferation and the colony formation, as well as suppressed the migration and invasion. In the in vivo model, Id4 overexpression inhibited the tumor growth and metastasis in the nude mice. Furthermore, Id4 overexpression upregulated the expression of proteins associated with cell proliferation, inhibited the PI3K/AKT pathway, and suppressed epithelial-mesenchymal transition (EMT) of HCT116 cells. Moreover, Id4 significantly decreased cytokeratin 18 (CK18) expression, but CK18 overexpression in Id4 expressing HCT116-Id4 cells rescued the activation of AKT, p-AKT, MMP2, MMP7, and E-cadherin. Collectively, our study indicated Id4 may inhibit CRC growth and metastasis through inhibiting the PI3K/AKT pathway in a CK18-dependent manner and suppressing EMT. Id4 may become a target for the treatment of CRC.

Isolation and evolutionary analyses of gout-associated goose astrovirus causing disease in experimentally infected chickens.

Astroviruses are a common cause of gastroenteritis in humans and animals. They are also associated with extraintestinal infections, including hepatitis in ducklings, nephritis in chickens, as well as fatal meningitis and encephalitis in humans and other mammals. Since 2014, outbreaks of disease characterized by visceral gout and swelling of kidneys have been reported in goslings and ducklings in China, with the causative agent revealed to be a novel avian astrovirus designated goose astrovirus (GoAstV). In the present study, this novel gout-associated GoAstV was identified in diseased goslings from 2 farms in Hunan province, China. Three genomes were successfully sequenced and analyzed and were shown to have high identities of 99.7 to 99.8% between each other, with some specific amino acid alterations revealed in open reading frame 2 when compared with other gout-associated GoAstVs. Two strains were further efficiently isolated in the DF-1 chicken fibroblast cell line with high virus titers of 1011 viral genomic copies per mL of culture media. A pilot virus challenge study using GoAstV in chickens demonstrated that this virus can cause clinical visceral gout in chickens, indicating its ability to cross the species barrier. Based on the phylogenetic analyses of capsid sequences, the identified GoAstVs were proposed to be classified into 2 genotypes, GoAstV1 and GoAstV2, and the novel gout-associated GoAstVs were all clustered in GoAstV2. Further Bayesian inference analyses indicated a nucleotide substitution rate of 1.46 × 10-3 substitutions/site/year for avian astrovirus based on open reading frame 2 sequences, and the time to the most recent common ancestor of GoAstVs was estimated to be around 2011. This is the first report to confirm GoAstV can infect chickens while also providing an estimation of the evolutionary rates of Avastroviruses.

Novel circovirus species identified in farmed pigs designated as Porcine circovirus 4, Hunan province, China.

In pigs, three circovirus species within the genus Circovirus have been identified so far, including the non-pathogenic Porcine circovirus 1 (PCV1), the pathogenic Porcine circovirus 2 (PCV2) and the recently identified Porcine circovirus 3 (PCV3). In April 2019, a new circovirus with a distinct relationship to other circoviruses was identified in several pigs with severe clinical disease in Hunan province, China. The size of the viral genome, tentatively designated as porcine circovirus type 4 (PCV4), is 1,770 nucleotides (nt). PCV4 shows the highest genomic identity to mink circovirus (66.9%) and has identities of 43.2%-51.5% to the other PCV genomes. Two major genes, a replicase (Rep) gene spanning 891 nt and a capsid (Cap) gene spanning 687 nt, were predicted. Furthermore, a TaqMan® real-time polymerase chain reaction (PCR) targeting the replicase gene was developed to investigate the prevalence of PCV4 in 187 clinical samples from Hunan province, China. The results revealed an overall PCV4 prevalence of 12.8%, with the highest positive rates in nasal swabs (28.5%, 6/21) followed by serum samples (13.4%, 11/82). The clinical significance and pathogenesis of this virus needs further investigation.

Intratumoral IL-12 Gene Therapy Inhibits Tumor Growth In A HCC-Hu-PBL-NOD/SCID Murine Model.

PURPOSE: This study aimed to evaluate the efficacy and safety of intratumoral IL-12 gene therapy in an HCC-hu-PBL-NOD/SCID mouse model. MATERIALS AND METHODS: The HCC murine model was generated in NOD/SCID mice, and mice with grafted tumors were injected intraperitoneally with 2 × 107 human peripheral blood lymphocytes 14 days after modeling. After 4 days, mice were randomly divided into the 9597/IL-12 group, the 9597/plasmid group and the PBS group. The changes of tumor volume were measured and mouse peripheral blood was sampled post-treatment for ELISA and CBA analyses, and the grafted tumors were collected 28 days post-treatment for immunohistochemistry, ELISA, CBA and detection of cell cycle and apoptosis. RESULTS: The tumor volume was smaller in the 9597/IL-12 group than in the 9597/plasmid and PBS groups on days 7, 14, 21, and 28 post-treatment (P < 0.05). Higher IL-12 levels were detected in the peripheral blood and the supernatants of grafted tumor homogenates in the 9597/IL-12 group than in the 9597/plasmid and PBS groups 7, 14, 21 and 28 days post-treatment (P < 0.05). IHC revealed higher counts of CD3+T cells, CD4+T helper cells, IFN-γ Th1 cells+ and S-100 protein positive dentric cells and lower MVD in the 9597/IL-12 group than in the 9597/plasmid and PBS groups (P < 0.05). Flow cytometry showed a significantly higher proportion of HCC cells at the G0/G1 phase and a significantly lower proportion of HCC cells at the S phase in the 9597/IL-12 group than in the PBS group (P < 0.05) and a greater apoptotic rate of HCC cells in the 9597/IL-12 group than in the 9597/plasmid and PBS groups (P < 0.05). CONCLUSION: Intratumoral IL-12 gene therapy may inhibit tumorigenesis with mild adverse effects in a HCC-hu-PBL-NOD/SCID murine model through inhibiting angiogenesis, arresting cells in G0/G1 phase and inducing apoptosis.

Genomic characterization of a novel astrovirus identified in Amur tigers from a zoo in China.

Astroviruses (AstVs) have a very wide range of hosts and are associated with enteric and extra-enteric disease in mammals and birds. Cross-species transmission of AstVs has been observed frequently. In the present study, the genome of a novel astrovirus from Amur tigers (Panthera tigris) from a zoo in China was characterized and was found to have the typical genomic features of other mammal AstVs. It showed the highest nucleotide sequence similarity (46.1-87.3% identity) to AstVs from cats, indicating a close phylogenetic relationship and possible cross-species transmission between them. To our knowledge, this is the first identification and characterization of AstV from tigers, and this virus is the third astrovirus identified in hosts of the family Felidae. The results of this study will be helpful for understanding the origin, genetic diversity, and cross-species transmission of AstV.

High genetic diversity and recombination events of porcine astrovirus strains identified from ill and asymptomatic pigs in 2017, Hunan Province, China.

Astroviruses (AstV) are associated with enteric and systemic disease in mammals and birds. Astroviruses have received increased attention recently as they have been found to be associated with sporadic neurologic disease in mammals including humans. In pigs, porcine astrovirus (PoAstV) can be widely detected and has been grouped in five genotypes (PoAstV1 to PoAstV5). In the present study, we detected multiple PoAstVs in serum samples, nasal swabs, and fecal swabs collected from pigs suffering from respiratory disease or diarrhea but also from asymptomatic pigs, indicating a wide tissue tropism of the identified PoAstV genotypes. Coinfection of different genotypes in the same pig was commonly observed, and within an individual pig a high genetic diversity was observed for viruses belonging to the same PoAstV genotype. Two complete genomes of PoAstV2-WG-R2/2017 and PoAstV4-WG-R2/2017 were successfully obtained and characterized, with genome sizes of 6396 and 6643 nucleotides, respectively. The PoAstV2-WG-R2/2017 genome showed identities of 67.2-77.4% to other known PoAstV2 genomes, and the PoAstV4-WG-R2/2017 genome showed identities of 72.8-80.5% to other known PoAstV4 genomes. The predicted spike domain of open reading frame 2 (ORF2) of these strains showed the highest genetic heterogeneity, with amino acid identities of 13.7-70.9% for PoAstV2-WG-R2/2017 to other known PoAstV2 strains, and identities of 24.4-63.3% for the PoAstV4-WG-R2/2017 to other known PoAstV4 strains. Possible recombination events were identified in each of the two sequences. Two subclades of PoAstV2 and three subclades of PoAstV4 were defined in the present analyses. The obtained data provide further evidence for extraintestinal infectivity of PoAstVs, and confirmed the high genetic diversity of PoAstVs and the coinfection potential of different PoAstV types in a single pig.

[Expression and significance of the NK cell receptors in primary hepatocellular carcinoma and paracancerous tissues].

AIM: To investigate the expression of the activating and inhibitory receptors on the surface of NK cells of primary hepatocellular carcinoma and its adjacent tissues, and the relationship between these two receptors and occurrence and development of primary liver cancer was analyzed. METHODS: The number and activity of the NK cells, the expression of the activating and the inhibitory receptors on the surface of those cells were detected flow cytometry and immunohistochemistry, which were obtained from 52 cases of primary hepatocellular carcinoma and its adjacent tissues. The relative analysis was done between those results and clinical relative factors. RESULTS: In the tissues of primary hepacellular carcinoma, the number of NK cells is lower than that in the adjacent tissues obviously (P<0.01); the expression of activating receptors, NKG2D and NKP44, is also lower than that in the adjacent tissues obviously (P<0.05); the expression of inhibitory receptors, CD158b and CD159a, is significantly higher than that in the adjacent tissues (P<0.05). A negative correlation was found between the expression of NKG2D, NKP30 and NKP44 and the clinical stage of the liver cancer. The expression of NKG2D, NKP30 and NKP44 was higher in patients with early and middle stages (P<0.05). The content of the inhibitory receptors of NK cells, CD158b and CD159a, is higher in tissues from patients with advanced cancer stage (P<0.05). That's also correlated with the level of AFP and the HBsAg. There is no significant statistical difference between the expression of NK receptors and the distant metastasis, tumor differentiation as well as the tumor size (P>0.05). CONCLUSION: The decrease of NK cell numbers and the activating NK cell receptors and the increase of the inhibitory receptors would be relevant to the incidence of primary hepacellular carcinoma.

Irradiated haploidentical donor leukocyte infusions as an adoptive immunotherapy strategy to induce host-versus-tumor effects.

AIMS AND BACKGROUND: Previous research has shown that irradiated splenocytes preserve the antitumor effect and induce relatively weaker graft-versus-host disease in parent C57BL/6~CB6F1 transplantation. The present study was designed to investigate the antitumor effect of 5-Gy-irradiated haploidentical donor leukocyte infusions (DLI) without prior bone marrow transplantation and the possibly involved mechanism in (H-2d/k)~(H-2b/d) infusion model systems. METHODS: Hepa 1-6 tumor-bearing mice were used to evaluate the antitumor effect and the possible mechanism of irradiated haploidentical DLI treatment. Changes in tumor volume, lymphocyte proliferation and cytotoxicity, IFN-gamma and IL-2 secretion and donor cell survival in vivo were analyzed. RESULTS: After irradiated haploidentical DLI treatment of the poorly immunogeneic Hepa 1-6 tumor mouse model, the donor cells were rejected and disappeared within 4 days. Surprisingly, an antitumor response was still observed. The infusion treatment effectively inhibited tumor growth and prolonged the survival of recipients, and this effect could be enhanced by combined treatment with cyclophosphamide and impaired by deleting donor-derived T cells. Moreover, the infusion treatment increased the levels of type 1 cytokines including IFN-gamma and IL-2, and enhanced the proliferation of lymphocyte subsets, particularly CD8 + T and NK cells. Specifically, multiple infusions proved to enhance the antitumor effect without inducing graft-versus-host disease. CONCLUSIONS: As an adoptive therapy, irradiated haploidentical DLI without bone marrow transplantation might be a promising and safe treatment for cancer.

[Significance of the expression of lymphocytes and cytokines infiltrating in HCC].

AIM: To reveal the classification of lymphocytes and expression of cytokines infiltrating in HCC, and investigate the significance of changes of immune microenvironment in HCC. METHODS: 76 tumor and non-tumor tissues of HCC were collected to detect the amount of immune cells in the tissues by FCM and immunohistochemistry (IHC). Th1/Th2 cytokines in tissues were detected by Cytometric bead array (CBA), and TGF-1, VEGF detected by ELISA. RESULTS: There were more CD3(+); T cells, CD4(+); Th cells, Treg cells, and CD45RO(+); memory T cells in tumors than in non-tumor tissues. On the contrary there were less CD8(+); CTLs in tumors. There was negative correlation between Treg and Th or CTL cells. CD69, which is the early activating factor, expressed less on CD3(+); T cells and NK cells in tumors than non-tumor tissues. Whereas HLA-DR, which is the late activating factor, expressed more on CD3(+); T cells in tumors than non-tumor tissues. More IL-10, TGF-1 and VEGF were secreted in tumors than non-tumor tissues. CONCLUSION: Along with the decrease of effective immune cells and increase of suppressor immune cells and cytokines, the lymphocytes infiltrating in the tumor were immune incompitence, which contributed to the tumorigenesis.

The combined administration of partially HLA-matched irradiated allogeneic lymphocytes and thalidomide in advanced renal-cell carcinoma: a case report.

Renal-cell carcinoma (RCC) is susceptible to immune therapy including the use of the nonmyeloablative allogeneic transplantation (NST). However, NST can produce severe toxicity, might not be appropriate for many patients with metastatic RCC. Other novel allogeneic immunotherapies are designed to induce an autologous immune response directed against the malignancy. In single-arm phase II trials, thalidomide has demonstrated a modest activity in the treatment of advanced RCC. Here we present a case report in which a patient with advanced RCC in the absence of transplant conditioning, that was receiving thalidomide, was infused with partially HLA-matched irradiated allogeneic lymphocytes. In this patient a complete response with weak acute graft-versus-host disease (GVHD) was observed. No evidence of the disease was present over the subsequent 36 months survival of the patient, suggesting that the infusions may have played a major role in the antineoplastic effect. A potential mechanism of this protocol may involve a host-versus-graft reactions-mediated antitumor effect against the malignancy. In addition, the present results suggest that a combination protocol with alternate treatment (e.g., chemotherapy) schedules merit further investigation in the management of various malignancies.

The regulating role of mutant IkappaBalpha in expression of TIMP-2 and MMP-9 in human glioblastoma multiform / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Our previous studies demonstrated that mutant IkappaBalpha (IkappaBalphaM) inhibited the occurrence, growth and angiogenesis of human glioblastoma multiform (GBM). However, the specific mechanism by which IkappaBalphaM regulates protein-degrading enzymes secreted from GBM to inhibit invasion and metastasis has remained unclear. The aim of the present study was to investigate the regulatory role and significance of IkappaBalphaM genes in the expression of tissue inhibitor of metalloproteinase (TIMP)-2 and matrix metalloproteinase (MMP)-9 in human GBM.</p><p><b>METHODS</b>We established the following four GBM cell lines stably expressing IkappaBalphaM by plasmid construction, gene transfection and screening for IkappaBalphaM protein expression: mutant IkappaBalpha-transfected cells (G36Delta-M), wild-type IkappaBalpha-transfected cells (G36Delta-W), empty plasmid transfected cells (G36Delta-P) and untransfected cells (G36Delta). The TIMP-2 and MMP-9 expression was detected by RT-PCR and Western blotting. Tumor cells were then implanted subcutaneously into nude mice to establish an animal model of ectopic tumor growth, and TIMP-2 and MMP-9 expression was determined by immunohistochemical methods.</p><p><b>RESULTS</b>The results showed that there was a significant increase in TIMP-2 expression and a significant decrease in MMP-9 expression in the G36Delta-M group at both the RNA and protein levels compared with the G36Delta-W group, G36Delta-P group and G36Delta group. Similar results were observed in the immunohistochemical staining analysis of tumor tissues. In the G36Delta-M group, TIMP-2 expression was significantly higher while MMP-9 expression was significantly lower than in the other three groups.</p><p><b>CONCLUSIONS</b>Our findings indicate that IkappaBalphaM inhibits the activation of NF-kappaB. It significantly up-regulates TIMP-2 expression in human malignant glioma cells and down-regulates the expression of MMP-9. Thus, IkappaBalphaM maintains the integrity of the extracellular matrix and further inhibits the growth and metastasis of tumor tissues.</p>

[The roles of soluble MICA in immune escape of breast tumor].

AIM: To determine the expression of soluble MICA (sMICA) in serum of patients with breast tumor, and explore the roles of sMICA in immune escape. METHODS: ELISA was used to examine the sMICA in peripheral blood. The expression of NKG2D were identified by Flow cytometry. The cytotoxicity of NK cells to breast cancer cells was observed with MTT assay. RESULTS: sMICA was not detected in the serum of healthy person, but(76.8+/-22.3) ng/L in breast benign tumor patients and (205.4+/-71.3) ng/L in breast malignant tumor patients. There was positive correlation between sMICA levels and breast cancer stage. After incubation with sMICA, NK cells got decrease in cytotoxicity from (76.2+/-6.7) % to (48.4+/-4.1) % .The expression of NKG2D and secretion of IFN-gamma decreased at the same time. IL-15 up-regulated the expression of NKG2D on NK cells and increased NK cells cytotoxicity to breast cancer cells. CONCLUSION: sMICA level is positive correlated with breast cancer TNM stage. sMICA reduced the expression of NKG2D, impaired NK-mediated immune surveillance and led to immune escape of breast tumor. IL-15 could up-regulate the expression of NKG2D and increase NK cells cytotoxicity.

The cytotoxicity of a Grb2-SH3 inhibitor in Bcr-Abl positive K562 cells.

Chronic myelogenous leukemia (CML) is characterized by the presence of Bcr-Abl oncoprotein. Gleevec has been designed to treat many CML patients by specifically targeting Bcr-Abl, but resistance to it is already apparent in many cases. In CML cells, Bcr-Abl activates several signaling pathways, including the Ras-dependent pathway, in which growth factor receptor binding 2 (Grb2) acts as an adaptor protein. A specific Grb2-SH3 inhibitor (denoted as peptidimer-c) that disrupts Grb2-Sos complex was designed and synthesized in our laboratory. In this study, we investigated the effect and the molecular mechanism of this inhibitor. Peptidimer-c was shown to bind to Grb2 in K562 cells, a cell line over-expressing Bcr-Abl oncoprotein. It caused cytotoxicity in the cells, and inhibited their ability of colony formation in the semi-solid medium. It was shown to induce apoptosis of K562 cells in a dose-dependent mode, the apoptotic effect of peptidimer-c being associated with caspase-3 activation. The effect of peptidimer-c on growth inhibition was also shown to be accompanied by S-phase arrest of cell cycle mediated by down-regulation of cyclin A and Cdk2, as well as phospho-Cdk2. The above results indicated that peptidimer-c may be another potential therapeutic agent for CML, which can induce S-phase arrest in the Bcr-Abl positive K562.

Effect of shRNA-mediated silence of H-ras gene on proliferation of human SACC-M cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To examine the effects of H-ras gene silence on cell cycle, proliferation and apoptosis of salivary adenoid cystic carcinoma -M (SACC-M) cell lines.</p><p><b>METHODS</b>The plasmid H-ras-shRNA, containing the sequence of shRNA targeting H-ras, and HK-shRNA (without interfering effect) were constructed and transfected into SACC-M cells. The cell line with shRNA plasmid stable expression was isolated by G418. The expression levels of H-ras were detected by RT-PCR and protein immunofluorescent assay; cell cycle and cell apoptosis were analyzed by flow cytometry (FCM). The proliferation of cell was also determined by subcutaneous tumor formation in nude mice.</p><p><b>RESULTS</b>After transfection of H-ras-shRNA plasmid, the mRNA expression of H-ras in SACC-M cells was down-regulated by 61.80% and protein expression of H-ras was inhibited by 62.76%; the cell proliferation was inhibited obviously; the G0G1 phase cells were increased. The cell apoptosis rate of H-ras-shRNA group was significantly higher than that of HK-shRNA group (P <0.05). The volume of subcutaneous tumor in nude mice was significantly smaller in Hras-shRNA group than in control group.</p><p><b>CONCLUSIONS</b>The recombinant plasmid HRAS-shRNA could efficiently down-regulate the expression of H-ras gene and protein, induce apoptosis of SACC-M cells and simultaneously inhibit proliferation of these cells in vitro and in vivo.</p>

Construction of eukaryotic expression vector of short hairpin RNA targeting human xylosyltransferase-I gene / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To design and construct the plasmids expressing short hairpin RNA (shRNA) targeting human xylosyltransferase- I (XT- I) which is the initiating enzyme in the biosynthesis of proteoglycans (PC).</p><p><b>METHODS</b>Short chain oligonucleotides were designed according to the sequence of XT-I provided by GenBank. The DNA segments were gained through annealing after chemosynthesis, and were cloned into Pgenesil-1 vector. The recombinant XT- I shRNA expression vectors were identified by digestion and sequencing analysis. At last the constructed XT-I expression vectors were transfected into salivary adenoid cystic carcinoma cell line (ACC-M) by Lipofectomine 2000. The expression of green fluorescent protein (GFP) was detected by inverted fluorescent microscope and the rates of transfection were detected by flow cytometer. Semiquantitative RT-PCR was used to detect the expression of mRNA level of XT- I in transfected ACC-M cells and the protein expression of XT- I was detected by Western blot.</p><p><b>RESULTS</b>The plasmids expressing shRNA targeting XT-I gene are called WJ1, WJ2, WJ3, WJ4, WJ5 and WJ6. Successful constructions were identified by digestion and sequencing. The mean rate of transfection was 50.26%. ACC-M cells transfected with WJ1-WJ6 expressed GFP successfully. And by RT-PCR and Western blot, WJ3 showed the most powerful RNAi gene silencing of inhibitory. The inhibition rate was 72.39% of mRNA level and 70.18% of protein level respectively.</p><p><b>CONCLUSION</b>The XT-I shRNA expression vectors were constructed successfully which lays the foundation for RNAi study on the biosynthesis of PG in salivary gland tumors.</p>

[Effects of NKG2D and its ligands RAE-1 and H60 on graft-versus-tumor response].

The study was purposed to explore the effects of NKG2D receptor and its ligands RAE-1 and H60 on graft-versus-tumor (GVT) response induced by MHC haploidentical bone marrow/spleen cell transplantation. Female (BALB/c x C57BL/6) F1 mice (CB6F1, H-2K(b/d)) inoculated with H22 cells to develop a solid tumor model were the recipients, and bone marrow mixed with spleen cells of the healthy male C57BL/6 (H-2K(b)) mice were the donor cells. GVT response was observed after transplantation that from donor cells T and NK cells were purged with anti-CD3 and anti-NK monoclonal antibody, and the NKG2D receptor was blocked with anti-NKG2D monoclonal antibody, the expression levels of RAE-1 and H60 mRNA in tumor tissue were measured by means of semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) at different time points after transplantation. The results showed that the GVT response of transplantation was reduced after in vitro depletion of T and NK cells or blocking NKG2D receptor in donor cells of the graft, the expression levels of RAE-1 and H60 mRNA in tumor tissue increased after transplantation of haploidential bone marrow mixed with spleen cells. It is concluded that NKG2D and its ligands RAE-1 and H60 may play important roles in GVT response.

An experimental study on porcine fibroblasts transfected by dental matrix protein-1 gene / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the expression of dental matrix protein-l (DMP1) in porcine oral mucosa fibroblasts (POMF) transfected by DMP1 and the influences of the transfection.</p><p><b>METHODS</b>The full length of porcine DMP1 cDNA was linked into an eukaryotic expression vector pEGFP-C1. POMF and mesenchymal stem cells (MSC) were transfected with the pEGFP-DMP1. The expression of DMP1, dental sialoprotein (DSP), amelin and ameloblastin (Ambn) gene of transfected POMF and MSC were detected by RT-PCR. The expression of DMP1 and DSP protein was examined by immunocytochemical staining. The formation ratio of mineralized nodules of transfected cells was compared with un-transfected ones after mineralized induction. The formation of mineralized nodules of three-dimensional pellet transfected cells was compared with un-transfected ones after hematoxylin and eosin staining.</p><p><b>RESULTS</b>The constructed pEGFP-DMP1 could produce 4.7 kb and 1.5 kb fragments. DMP1 gene, DSP gene and Ambn gene were expressed by POMF after transfection. Immunohistochemical staining and the quantitative analysis of protein showed that DMP1 and DSP protein was positive in transfected POMF and MSC. The formation ratio of mineralized nodules of transfected POMF and MSC was higher than that of un-transfected ones (P < 0.05).</p><p><b>CONCLUSIONS</b>The expression of porcine DMP1 in POME after gene transfection can induce the expression of tooth-development-associated gene Ambn and DSP and enhance the formation of mineralized nodules.</p>