[Research progress in stent associated respiratory tract infection]

Airway stents are commonly used to treat patients with central airway obstruction, but several complications have been identified, including mucus plugging, granulation tissue, stent migration, and infection. Stent associated respiratory tract infection (SARTI) has often been neglected by the practicing clinicians. Therefore, we reviewed the available current literatures on the diagnosis and management of stent associated respiratory tract infection.

HIF-1α inhibitor YC-1 suppresses triple-negative breast cancer growth and angiogenesis by targeting PlGF/VEGFR1-induced macrophage polarization

Triple negative breast cancer (TNBC) is an invasive and metastatic phenotype of breast cancer with limited treatment options. Published studies have demonstrated an inhibitory effect of HIF-α inhibition by its inhibitor YC-1 (lificiguat) on growth and angiogenesis of TNBC. However, the underlying mechanism remains poorly understood. In the current paper, our results show that HIF-1α inhibitor significantly inhibited TNBC growth by increasing cellular apoptosis and decreasing MVD, independent of a cell-autonomous mechanism in both endothelial and tumor cells. Genetic screening and in vivo experiments showed that a large number of M2-polarized TAMs accumulated in the hypoxic peri-necrotic region (PNR), where placental growth factor (PlGF) and its ligand, vascular endothelial growth factor receptor-1 (VEGFR-1) were upregulated. Furthermore, YC-1 skewed the polarization of TAMs away from M2 to M1 phenotype, therefore inhibiting TNBC angiogenesis and growth. This effect was further abrogated by VEGFR-1 neutralization and TAM depletion following clodronate liposome injection. These findings provide preclinical evidence for an indirect mechanism underlying YC-1-induced suppression of TNBC growth and angiogenesis, thereby offering a treatment option for TNBC.

Iatrogenic femoral artery pseudoaneurysm surgically repaired with combined bovine pericardial roll and autologous great saphenous vein grafts

Iatrogenic femoral artery pseudoaneurysm caused by invasive procedures is one of the common complications for endovascular interventions. We present a case of a young male with a complex iatrogenic femoral artery pseudoaneurysm as a result of iatrogenic femoral artery puncture. The defective femoral artery was repaired with combined bovine pericardial tube and autologous great saphenous vein grafts. Computed tomography angiography showed the grafts were still patent one year after the surgery.

[Treatment outcome of 100 patients with hepatoblastoma based on a new risk stratification]

Objective: To provide the risk stratification method of hepatoblastoma (HB) suitable for implementation in China and explore the new treatment method for high-risk HB patients. Methods: A total of 100 cases of children and adolescents under 18 years old with newly diagnosed HB in Sun Yat-sen University Cancer Center and Sun Yat-sen University First Affiliated Hospital from September 2014 to September 2018 were included. According to the clinical stage, AFP level, pathological subtype and other factors, patients were stratified into four groups: extremely low-, low-, intermediate- and high-risk. The patients at very low risk were treated with surgery only and followed-up. The patients at very low risk were treated with C5V(Cisplatin+ 5-Fluroracil+ Vincristine) regimen for 4 courses. The patients at intermediate risk were treated with C5VD(Cisplatin+ 5-Fluroracil+ Vincristine+ Doxorubicin)regimen before and after surgery for 6-8 courses. The patients at high risk were treated with C5VD and IIV (ifoshamide+ irinotecan+ vincristine) alternately before and after surgery for 8 courses. Results: One hundred patients were stratified into extremely low-risk, low-risk, medium-risk and high-risk groups for 2, 10, 51 and 37 cases, respectively. Eighty three cases had evaluable lesions before chemotherapy. Among them, 65 patients achieved partial remission, stable disease and progressive disease were observed in 10, and 8 cases, respectively, with a response rate of 78.3%. During a median follow-up of 20 months, 30 patients experienced tumor relapse or progression, and 27 of them died. The 2-years progression-free survival (PFS) and overall survival (OS) rates were 69.2% and 72.0%, respectively. The 2-years PFS rates of patients with extremely low risk, low risk, medium risk and high risk were 100%, 88.9%, 75.3% and 43.2%, respectively. The 2-years OS rates were 100%, 100%, 81.0% and 44.8%, respectively. Conclusions: The novel HB risk classification is simple and feasible. With active comprehensive treatment, patients at extremely low-, low- and medium-risk have excellent outcomes. The survival rate of high-risk HB patients remains to be improved, and new treatment strategies need to be explored.

[A single-center retrospective analysis of 85 children and adolescents with limited-stage Hodgkin lymphoma]

Objective: To summarize the efficiency and long-term outcomes of limited-stage Hodgkin lymphoma in children and adolescents with ABVD therapy and determined whether omitting radiotherapy for a low-risk patient enabled the achievement of complete response (CR) after chemotherapy. Methods: We retrospectively analyzed data from 13 y (2004-2016) from patients aged ≤18 y with limited-stage HL admitted to the Sun Yat-sen University Cancer Center. Patients received treatment with ABVD chemotherapy alone or ABVD chemotherapy followed by low-dose involved field radiotherapy. Results: Total 85 subjects were eligible for study inclusion; the median age was 12 (3-18) y; 66 (77.6%) were men, 80 (94.1%) had stage-II disease, 56 (65.9%) were at low-risk, and the median follow-up duration was 72 (8-196) months; 12 relapsed, 2 had secondary neoplasm, and 2 died. The 5-year event free survival (EFS) was (85.6±3.8) %, and the overall survival (OS) was 100%. The 5-year EFS and OS was (89.1±4.2) % and 100%, respectively, for the low-risk cohort and (79.3±7.5) % and 100%, respectively for the intermediate-risk cohort. Among the 39 low-risk patients who achieved CR after chemotherapy, 15 received treatment with chemotherapy followed by LD-IFRT. In the exploratory subset analysis, the low-risk cohort who achieved CR after chemotherapy, the 5-year EFS for comparing ABVD alone with chemotherapy followed by LD-IFRT was (87.0±7.0) % versus 100% (P=0.506) , and the OS was 100% for both the groups. Conclusions: Our retrospective analysis showed excellent survival of limited-stage HL patients with ABVD therapy. For patients who achieving CR after chemotherapy with low-risk HL, received chemotherapy followed by LD-IFRT does not improve 5-year OS and EFS. The use of risk- and response-based stratification may facilitate the development of effective and less toxic protocols.

Percutaneous suture technique with ProGlide to manage vascular access pseudoaneurysm after percutaneous coronary intervention procedure: A case report

Iatrogenic femoral artery pseudoaneurysm is a common complication of the endovascular procedures. Manual compression and thrombin injection are the conventional techniques to occlude the pseudoaneurysms. However, there are still some failed cases that applied these treatment options. The aim of the study is to seek a potential and alternative method with ProGlide system to close the pseudoaneurysm. During April 2018 to February 2019, 2 patients with iatrogenic pseudoaneurysm of the superficial femoral were treated with the suture-base closure device--ProGlide. After punctured the pseudoaneurysm and placed a 6-F sheath, the guide wire was placed in the right femoral artery via the access of the pseudoaneurysm neck. Then the pseudoaneurysm neck was sutured by ProGlide to occlude the blood supply to the pseudoaneurysm. These 2 patients were cured with no complications and complaints, which revealed that percutaneous suture technique with ProGlide at the neck level of pseudoaneurysm provides a novel method for the management of vascular access pseudoaneurysm, especially in those with a wide and short neck.

Metformin inhibits metastatic breast cancer progression and improves chemosensitivity by inducing vessel normalization via PDGF-B downregulation

Background

Vascular maturity and functionality are closely associated with tumor progression and chemosensitivity. The antidiabetic agent metformin has shown its ability to inhibit tumor angiogenesis in metastatic breast cancer models. However, it remains unclear if or how metformin remodels the abnormal vasculature of metastatic breast cancer, while inhibiting angiogenesis.

Methods

Metastatic breast cancer models were constructed to compare microvessel density (MVD), vascular maturity and function, lung metastasis and chemosensitivity in metformin-treated or untreated mice. Protein array assay and transcriptome sequencing were performed for genetic screening. Lentiviral shRNA-PDGF-B transfection was used for observing the contribution of PDGF-B knockdown to metformin’s vascular effects.

Results

Metastatic breast cancers were characterized by an excessively angiogenic, immature and morphologically abnormal vasculature. Compared to control, metformin significantly reduced MVD, leakage and hypoxia, and increased vascular mural cells coverage and perfusion, namely, “vessel normalization”. Metformin at human blood concentrations had no direct effect on the migration and proliferation of cancer cells. Based on that, reduced lung metastasis of the primary tumor and improved chemosensitization by metformin were assumed to be mediated via metformin’s vascular effects. Further results of genetic screening and in vivo experiments showed that the downregulation of platelet-derived growth factor B (PDGF-B) greatly contributed to the metformin-induced vessel normalization.

Conclusions

These findings provide pre-clinical evidences for the vascular mechanism of metformin-induced metastasis inhibition and the chemosensitization of metastatic breast cancers.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1211-2) contains supplementary material, which is available to authorized users.

[Impact of intensified maintenance therapy on the prognosis of children and adolescents with advanced lymphoblastic lymphoma]

目的

探讨增加维持治疗强度对Ⅲ期和Ⅳ期儿童青少年淋巴母细胞淋巴瘤（Lymphoblastic lymphoma, LBL）患者预后的影响。

方法

回顾性分析接受BFM-NHL-90/-95方案治疗且未做纵隔和中枢预防性放疗的Ⅲ期和Ⅳ期儿童青少年LBL患者的治疗结果。研究分组：1998年至2005年收治的患者于维持治疗阶段，在口服巯基嘌呤和甲氨蝶呤的基础上，定期采用“足叶乙甙+阿糖胞苷”和大剂量甲氨蝶呤交替进行化疗，为强化维持治疗组；其余为非强化维持治疗组。

结果

187例LBL患者纳入研究，其中强化维持治疗组52例，非强化维持治疗组135例，两组患者的性别、年龄、免疫分型、临床分期、危险度分层、受累部位的差异均无统计学意义（P值均>0.05）；中位随访48（0.5～221）个月，两组患者的5年无事件生存（EFS）率分别为（76.9±5.8）%和（77.9±4.3）%（χ²＝0.249，P＝0.617），5年总生存（OS）率分别为（78.8±5.7）%和（79.8±4.1）%（χ²＝0.353，P＝0.552），差异均无统计学意义；亚组分析结果显示，两组患者在不同临床分期（Ⅲ/Ⅳ期）、免疫分型（T/B-LBL）和危险分层（中/高危）中的EFS、OS率差异均无统计学意义（P值均>0.05）。维持治疗期间，强化维持治疗组和非强化维持治疗组患者Ⅲ、Ⅳ级骨髓抑制发生率分别为55.8%和18.5%（χ²＝25.363，P<0.05）。

结论

提高维持治疗强度并未提高Ⅲ期和Ⅳ期儿童青少年LBL患者的长期生存且可增加骨髓抑制等治疗相关不良反应。

[Efficacy and safety of decitabine in combination with G-CSF, low-dose cytarabine and aclarubicin in MDS-EB and AML-MRC]

Objective: To evaluate the clinical efficacy and safety of decitabine in combination with lower-dose CAG regimen (G-CSF, cytarabine and aclarubicin; D-CAG regimen) in the treatment of myelodysplastic syndromes with excess blasts (MDS-EB) and acute myeloid leukemia with myelodysplasia-related changes (AML-MRC), compared to standard CAG regimen. Methods: A total of 42 patients with newly diagnosed MDS-EB and AML-MRC from May 2011 to March 2017 were included in the retrospective study. 21 cases were initially treated with G-CSF for priming, in combination with cytarabine of 10 mg/m(2) q12h for 14 days and aclarubicin of 20 mg/d for 4 days (CAG regimen) and the other 21 cases were initially treated with decitabine of 20 mg/m(2) for 5 days and lower-dose CAG regimen (cytarabine of 10 mg/m(2) q12h for 7 days, aclarubicin of 10 mg/d for 4 days, and G-CSF for priming (D-CAG regimen). After two cycles of induction chemotherapy, the patients who obtained complete remission(CR) received consolidation chemotherapy or hematopoietic stem cell transplantation (HSCT). Results: Among a total of 42 patients, the median age was 52.5 years (18-65 years) and 64.3% of them were male. Baseline characteristics of patients between D-CAG group and CAG group showed no significant differences. The CR for patients in D-CAG group was 81.0% (17/21), compared to 52.4% (11/21) in CAG group after 2 cycles of therapy (χ(2)=3.857, P=0.050). The overall response rate (ORR) for patients in D-CAG group and CAG group was 85.7% (18/21) and 76.2% (15/21) respectively, without significant difference (χ(2)=1.273, P=0.259). By December 2017, the median follow-up of D-CAG group and CAG group was 13(6-32) months and 15(2-36) months respectively. Finally, 10 patients in D-CAG group and 7 patients in CAG group received HSCT respectively. Except patients receiving HSCT, the median leukemia-free survival (LFS) time for patients in D-CAG group and CAG group was 18.0 (95%CI 6.6-29.4) months and 11.0 (95%CI 0-23.9) months respectively. Probabilities of 12 months LFS for D-CAG group and CAG group were (63.6±14.5)% and (50.0±13.4)% respectively, without difference (χ(2)=0.049, P=0.824). Except patients receiving HSCT, there were 2 deaths in D-CAG group and 7 deaths in CAG group respectively. The cumulative probabilities of 12 months OS for non-HSCT patients in D-CAG group and CAG group were (90.9±8.7)% and (61.5±13.5)% respectively, without significant difference (χ(2)=1.840, P=0.175). The incidences of side effects between D-CAG group and CAG group did not show significant differences (P=0.479), and the main side effects included cytopenias, pneumonia, infections of skin and soft tissues, neutropenic patients with fever, liver dysfunction. Conclusion: The decitabine in combination with lower-dose CAG regimen improved CR for patients with MDS-EB and AML-MRC, and was a promising choice.

[Influence of gender, age and season on thyroid hormone reference interval]

Objective: Using clinical "big data" , to investigate the factors that affect the levels of thyroid hormones, and to explore the partitioning criteria for reference intervals (RI) of these hormones. Methods: An observation study was conducted. Information of 107 107 individuals undergoing routine physical examination in Peking Union Medical College Hospital from September 1(st,) 2013 to August 31(st,) 2016 was collected, thyroid hormone of these subjects were detected. To explore the test results distribution and differences of TSH, FT4 and FT3 by gender and age; according to the seasonal division standard of China Meteorological Administration, the study period was divided into four seasons, and the seasonal fluctuation on TSH was analyzed.To define the appropriate partition by gender, age and season according to significant difference analysis. Results: In male and female, the distributions of TSH were 1.779(0.578-4.758), 2.023(0.420-5.343)mU/L, respectively, and the level of TSH in female was higher than in male (Z=-37.600, P<0.001). The distributions of FT4 were 0.127(0.098-0.162), 0.117(0.091-0.151) μg/L, the distributions of FT3 were 3.33(2.47-3.74), 3.01(2.35-3.57)ng/L. And the level of FT4, FT3 in female were significantly lower than in male (Z=-94.000, -154.600, all P<0.001). Furthermore, males were divided into two groups by 65 years old and female were divided by 50 years old, respectively, and the distributions of TSH in male and female of older group were 1.818(0.528-5.240), 2.111(0.348-5.735)mU/L, in younger group were 1.778(0.582-4.696), 1.991(0.427-5.316)mU/L. The level of TSH in older group was significantly higher than in younger group (Z=-2.269, -10.400, all P<0.05), and the distribution of TSH in older group was much wider than in younger. The distribution of whole in spring, summer and autumn was 1.869( 0.510-5.042)mU/L, in winter was 1.978(0.527-5.250) mU/L, and the difference between them had statistical significance (Z=-15.000, P<0.001). Conclusions: Gender and age significantly affect the serum levels of TSH, FT4, and FT3, the distribution of TSH in female and elder group are wider than in male, and that of FT4, FT3 are lower.Seasons significantly affect the serum TSH level, the peak value is observed in winter. There are obviously differences between "rough" RIs and manufacture recommended RIs. Each laboratory should establish reference intervals for thyroid hormones on the premise of appropriate grouping.

Metformin's antitumour and anti-angiogenic activities are mediated by skewing macrophage polarization

Beneficial effects of metformin on cancer risk and mortality have been proved by epidemiological and clinical studies, thus attracting research interest in elucidating the underlying mechanisms. Recently, tumour‐associated macrophages (TAMs) appeared to be implicated in metformin‐induced antitumour activities. However, how metformin inhibits TAMs‐induced tumour progression remains ill‐defined. Here, we report that metformin‐induced antitumour and anti‐angiogenic activities were not or only partially contributed by its direct inhibition of functions of tumour and endothelial cells. By skewing TAM polarization from M2‐ to M1‐like phenotype, metformin inhibited both tumour growth and angiogenesis. Depletion of TAMs by clodronate liposomes eliminated M2‐TAMs‐induced angiogenic promotion, while also abrogating M1‐TAMs‐mediated anti‐angiogenesis, thus promoting angiogenesis in tumours from metformin treatment mice. Further in vitro experiments using TAMs‐conditioned medium and a coculture system were performed, which demonstrated an inhibitory effect of metformin on endothelial sprouting and tumour cell proliferation promoted by M2‐polarized RAW264.7 macrophages. Based on these results, metformin‐induced inhibition of tumour growth and angiogenesis is greatly contributed by skewing of TAMs polarization in microenvironment, thus offering therapeutic opportunities for metformin in cancer treatment.

Activation of AMPK by simvastatin inhibited breast tumor angiogenesis via impeding HIF-1α-induced pro-angiogenic factor

Substantial data from preclinical studies have revealed the biphasic effects of statins on cardiovascular angiogenesis. Although some have reported the anti‐angiogenic potential of statins in malignant tumors, the underlying mechanism remains poorly understood. The aim of this study is to elucidate the mechanism by which simvastatin, a member of the statin family, inhibits tumor angiogenesis. Simvastatin significantly suppressed tumor cell‐conditioned medium‐induced angiogenic promotion in vitro, and resulted in dose‐dependent anti‐angiogenesis in vivo. Further genetic silencing of hypoxia‐inducible factor‐1α (HIF‐1α) reduced vascular endothelial growth factor and fibroblast growth factor‐2 expressions in 4T1 cells and correspondingly ameliorated HUVEC proliferation facilitated by tumor cell‐conditioned medium. Additionally, simvastatin induced angiogenic inhibition through a mechanism of post‐transcriptional downregulation of HIF‐1α by increasing the phosphorylation level of AMP kinase. These results were further validated by the fact that 5‐aminoimidazole‐4‐carboxamide ribonucleotide reduced HIF‐1α protein levels and ameliorated the angiogenic ability of endothelial cells in vitro and in vivo. Critically, inhibition of AMPK phosphorylation by compound C almost completely abrogated simvastatin‐induced anti‐angiogenesis, which was accompanied by the reduction of protein levels of HIF‐1α and its downstream pro‐angiogenic factors. These findings reveal the mechanism by which simvastatin induces tumor anti‐angiogenesis, and therefore identifies the target that explains the beneficial effects of statins on malignant tumors.

Suppression of hypoxia-induced excessive angiogenesis by metformin via elevating tumor blood perfusion

The anti-diabetic metformin has been demonstrated to be effective in suppression of tumor progression via multiple mechanisms, in which angiogenic inhibition is involved. Hypoxia is a common feather of malignant tumor and promotes angiogenesis via induction of pro-angiogenic factors. However, the effect of metformin on tumor hypoxia and the association with angiogenic inhibition are still unclear. In the current study, we investigated the effects of metformin on both tumor blood perfusion and hypoxia-induced excessive angiogenesis. In the tumor region adjacent to necrosis, aberrantly excessive angiogenesis resulted from hypoperfusion-induced intense hypoxia and greatly contributed to the high average levels of both microvessel density and vascular branch density. Metformin administration increased the percentage of lectin-perfused vessels and reduced hypoxyprobe-positive area. This metformin-induced amelioration of hypoxia was accompanied by a significant reduction in expressions of both HIF-1α and angiogenesis-associated factors (AAFs). Consequently, inhibited excessive angiogenesis in hypoxic peri-necrotic region was observed in metformin-treated tumor. Further stable knockdown of HIF-1α abrogated hypoxia-induced AAFs in vitro and reduced both microvessel density and area of fitc-conjugated dextran that leaked outside the vascular lumen. Taken together, metformin ameliorated tumor hypoxia and restrained HIF-1α-induced expressions of AAFs through elevating tumor blood perfusion, thus suppressing the excessive tumor angiogenesis.

An improved RT-IPCR for detection of pyrene and related polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous homogeneous chemicals which are well known by carcinogens, mutagens and endocrine disorder. Here, an improved real-time immuno-PCR (RT-IPCR) was developed for detection of pyrene and its homologs in water samples. The PAHs in sample compete with pyrene-modified DNA to bind with monoclonal antibody (McAb) coated on PCR plate. The reporter DNA was exponentially amplified by real-time PCR instrument using Fast Start universal SYBR Green Master (ROX) kit. Only two reaction steps were needed to accomplish the detection. The assay had a good linear range from 5 pmol L(-1) to 5 nmol L(-1) with a detection limit of 3.5 pmol L(-1). For application assay, the average recoveries from tap water, lake water and mineral water were 98.4%, 98.2% and 99.7%, respectively which showed a good correlation (R(2)=0.9906) with those from GC-MS. The results indicated that the improved RT-IPCR seems to be a potential method for simple and ultrasensitive detection of pyrene and some homologues in environment water samples.

Reducing dioxin formation by adding hydrogen in simulated fly ash

In this study, simulated fly ash containing CuO/CuCl2 was heated at 350 °C in a flow of N2 and also in a nitrogen flow containing 10 vol% H2, to evaluate the influence of hydrogen adding on dioxin formation. The total polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) output derived from the CuO sample under N2 and 10 % H2 was 7.382 and 0.708 ng/g, respectively. As for CuCl2, it was 589 and 46.1 ng/g, respectively. The results show that the hydrogen adding has a good inhibition effect on PCDD/F formation; the inhibition rate was higher than 90 % for PCDD/Fs. HCl and NH3 were detected by Gasmet in the flue gas; the probable inhibition mechanism of hydrogen reaction was proposed, based on our measurements and others' researches.

A CD44 specific peptide developed by phage display for targeting gastric cancer

OBJECTIVE

To develop a peptide probe that could be used for gastric cancer detection via binding to CD44 protein with specificity and affinity.

RESULTS

A 12-mer phage peptide library was screened against immobilized CD44 protein. Bound phage counts using ELISA were performed to identify phage clones carrying the most highly selective peptide, which termed RP-1. Immunofluorescence and flow cytometry analysis indicated that the consensus peptide RP-1 could bind to CD44-positive gastric cancer cells with mean fluorescence intensities significantly higher than that of CD44-negative cells. CD44 knockdown led to decreased binding activity of RP-1 to the same cell line. Tissue array technique was used to identify the relationship (r = 0.556) between peptide binding and CD44 detection on gastric cancer tissues. Further, the hyaluronan-binding domain of CD44 was docked with RP-1 using computer modeling/docking approaches, revealing a RP-1/CD44 interaction with geometrical and energy match (-8.6 kcal/mol).

CONCLUSIONS

The RP-1 peptide we screened exhibits affinity and specificity to CD44 on cells and has the potential to be used as a candidate probe for gastric cancer cell targeting.

Recombinant lentivirus with enhanced expression of caudal-related homeobox protein 2 inhibits human colorectal cancer cell proliferation in vitro

Caudal-related homeobox protein 2 (CDX2), a tumor suppressor in the adult colon, is overexpressed under a non-cancer specific cytomegalovirus promoter in certain tumor cells; furthermore, non-specific expression of CDX2 may result in aberrant side effects in normal cells. The human telomerase reverse transcriptase (hTERT) promoter is active in the majority of cancer cells but not in normal cells. Hypoxia is a key feature of solid tumors, and targeted genes may be significantly upregulated by five copies of hypoxia-response elements (HREs) under hypoxic conditions. However, the effect of CDX2 overexpression, as controlled by five copies of HREs and the hTERT promoter, on human colorectal cancer (CRC) cell proliferation in vitro remains to be fully elucidated. In the current study, a recombinant lentivirus containing the CDX2 gene under the control of five HREs and the hTERT promoter was generated. An immunofluorescence assay was used to detect CDX2 expression by the 5HhC lentivirus, whereas an MTT assay was used to detect the effects of CoCl₂ on the viability of LoVo cells. Western blot analysis was conducted in order to determine the relative ratios of recombinant CDX2 protein to the internal control β-actin, following 5HhC/LoVo cell culture under normoxic and hypoxic conditions (100, 200, 300, 400 or 500 µmol/l CoCl₂) for 24 h, then for 12, 24 or 36 h with the optimal concentration (300 µmol/l) of CoCl₂. Reverse transcription polymerase chain reaction analysis was used to determine the transcription of recombinant CDX2 mRNA following culture of 5HhC/LoVo cells under normoxic or hypoxic conditions. Finally, a cloning assay was used to detect the proliferative ability of 5HhC/LoVo and 5Hh cells. High CDX2 expression was observed in hTERT-positive LoVo cells under hypoxic conditions, an effect which was mimicked by treatment with CoCl₂ to inhibit LoVo cell proliferation in vitro. High expression of CDX2 therefore provides a promising strategy for the development of novel targeted treatments and gene therapy for CRC.

Magnetic bead and gold nanoparticle probes based immunoassay for β-casein detection in bovine milk samples

In this work, a double-probe based immunoassay was developed for rapid and sensitive determination of β-casein in bovine milk samples. In the method, magnetic beads (MBs), employed as supports for the immobilization of anti-β-casein polyclonal antibody (PAb), were used as the capture probe. Colloidal gold nanoparticles (AuNPs), employed as a bridge for loading anti-β-casein monoclonal antibody (McAb) and horseradish peroxidase (HRP), were used as the amplification probe. The presence of β-casein causes the sandwich structures of MBs-PAb-β-casein-McAb-AuNPs through the interaction between β-casein and the anti-β-casein antibodies. The HRP, used as an enzymatic-amplified tracer, can catalytically oxidize the substrate 3,3',5,5'-tetramethylbenzidine (TMB), generating optical signals that are proportional to the quantity of β-casein. The linear range of the immunoassay was from 6.5 to 1520ngmL(-1). The limit of detection (LOD) was 4.8ngmL(-1) which was 700 times lower than that of MBs-antibody-HRP based immunoassay and 6-7 times lower than that from the microplate-antibody-HRP based assay. The recoveries of β-casein from bovine milk samples were from 95.0% to 104.3% that had a good correlation coefficient (R(2)=0.9956) with those obtained by an official standard Kjeldahl method. For higher sensitivity, simple sample pretreatment and shorter time requirement of the antigen-antibody reaction, the developed immunoassay demonstrated the viability for detection of β-casein in bovine milk samples.

In vivo tumor co-transfection with superantigen and CD80 induces systemic immunity without tolerance and prolongs survival in mice with hepatocellular carcinoma

BACKGROUND

Since transfection of established tumors with immunostimulatory genes can elicit antitumor immunity, we treat mouse HCC with in vivo transfection of superantigen SEA and/or costimulatory molecule CD80 and evaluated the safety and efficacy.

METHODS

Mice with HCC were treated with lipid-complexed plasmid DNA encoding staphylococcal enterotoxin A and/or CD80. Then the mice were evaluated for tumor regression, systemic immunologic responses, survival times and treatment-associated toxicity.

RESULTS

Of all treated mice, the overall response rates (complete or partial remission) for SEA, CD80 and SEA/CD80 treated mice in this study were 65%, 60% and 75% separately, and were significantly higher than that of untreated mice. Most of the treat mice completed the therapy without any significant reaction. CTL activity increased with time of treatment and correlated temporally with an objective tumor response. Also our results indicated that local intratumoral expression of SEA did not lead to detectable deletion or anergy of SEA-reactive spleen T cells. Survival times for hepatoma mice in this study treated by intratumoral injection of SEA, CD80 and SEA/CD80 were prolonged significantly (P < 0.01) compared with the control mice.

Identification of HLA-A2-restricted CTL epitope encoded by the MAGE-n gene of human hepatocellular carcinoma

BACKGROUND

Identification of the cytotoxic T lymphocytes (CTL) restricted epitopes of tumor antigens opens up possibilities of developing a new cancer vaccine. For the MAGE-n has been demonstrated closely associated with hepatocellular carcinoma (HCC) and HLA-A2.1 is found in over 50% of HCC patients in China, we aim at identifying MAGE-n-encoded peptide presented by HLA-A2.1.

MATERIALS

A HLA-A2.1-restricted CTL epitope was identified by using an improved "reverse immunology" strategy: (a) computer-based epitope prediction from the amino acid sequence of MAGE-n antigen; (b) peptide-binding assay to determine the affinity of the predicted peptide with HLA-A2.1 molecule; (c) stimulation of primary T-cell response against the predicted peptides in vitro; and (d) testing of the induced CTLs toward HCC cells expressing MAGE-n antigen and HLA-A2.1.

RESULTS

Of the five tested peptides, effectors induced by a peptide of MAGE-n at residue position 159-167(QLVFGIEVV) lysed HCC cells expressing both MAGE-n and HLA-A2.1. Our results indicated that peptide QLVFGIEVV was a new HLA-A2.1-restricted CTL epitope capable of inducing MAGE-n specific CTLs in vitro.

CONCLUSIONS

Identification of the MAGE-n /HLA-A2.1 peptide QLVFGIEVV may facilitate peptide-based specific immunotherapy for HCC. The combination of epitope prediction, epitope reconstruction method and immunological methods can improve the efficiency and accuracy of CTL epitope studies.

Enzyme-antibody dual labeled gold nanoparticles probe for ultrasensitive detection of κ-casein in bovine milk samples

A dual labeled probe was synthesized by coating gold nanoparticles (AuNPs) with anti-κ-CN monoclonal antibody (McAb) and horseradish peroxidase (HRP) enzyme on their surface. The McAb was used as detector and HRP was used as label for signal amplification catalytically oxidize the substrate. AuNPs were used as bridges between the McAb and HRP. Based on the probe, an immunoassay was developed for ultrasensitive detection of κ-CN in bovine milk samples. The assay has a linear response range within 4.2-560 ng mL(-1). The limit of detection (LOD) was 4.2 ng mL(-1) which was 10 times lower than that of traditional McAb-HRP based ELISA. The recoveries of κ-CN from three brand bovine milk samples were from 95.8% to 111.0% that had a good correlation (R(2)=0.998) with those obtained by official standard Kjeldahl method. For higher sensitivity and as simple as the traditional ELISA, the developed immunoassay could provide an alternative approach for ultrasensitive detection of κ-CN in bovine milk sample.

A rapid immunomagnetic beads-based immunoassay for the detection of β-casein in bovine milk

An immunomagnetic beads-based enzyme-linked immunosorbent assay (IMBs-ELISA) was developed for the detection of β-casein in bovine milk. Immunomagnetic beads (IMBs) were employed as the solid phase. The anti-β-casein monoclonal antibody (McAb) bound to IMBs was used as capture probe and an anti-β-casein polyclonal antibody (PcAb), labelled with horseradish peroxidase (HRP), was employed as detector probe. Three reaction and two washing steps were needed. Each reaction needed 10 min or less, which significantly shortened detection compared with classic sandwich ELISA. β-Casein in bovine milk was detected across a linear range (2-128 μg mL(-1)). Application results were in accordance with the Kjejdahl method, which suggests the IMBs-ELISA is rapid and reliable for the detection of β-casein in bovine milk.

Production of a monoclonal antibody and development of an immunoassay for detection of Cr(III) in water samples

In this study we report the production of a monoclonal antibody (Mab) specific for Cr(III)-chelate and the development of a competitive immunoassay for detection of Cr(III) in water samples. In the assay, the complete antigen (Cr(III)-ITCBE-BSA) was used as coating antigen, and Cr(III)-ITCBE as competitor competes with coating antigen to bind with Mab. Using this approach, the spiked water samples with Cr(III) were detected. The linear range of the detection was 0.7-12.4 ng mL(-1). The limit of the detection (LOD) was 0.51 ng mL(-1). The spiked results were also confirmed by ICP-MS, which showed a good correlation (R(2)=0.997) between the two methods. The results indicated that the developed assay was reliable and suitable for the detection of Cr(III) in water samples.

Dioxins and furans releases in Iranian mineral industries

In this project, emissions of Poly-Chlorinated Dibenzo-p-Dioxins and Dibenzo-Furans (PCDD/Fs) were investigated and estimated for selected Iranian mining and ore processing industries, such as integrated iron & steel plant, primary production of aluminium and copper metal, and the production of cement. As a first step of this study the annual emission of PCDD/Fs was estimated at 120gTEQannum(-1) on the base of the UNEP standardised Toolkit for identification and quantification of dioxin and furan releases. Steel and cement were identified as major emission sources and earmarked for further scrutiny. For that reason, filter dust arising in these plants was sampled and analysed, as well as all raw materials employed. After extraction and clean-up according to standard methods, the resulting liquid samples were analysed and quantified by HRGC-HRMS. Complementary analyses using methods such as XRF, TGA/DTA were performed and the emission results statistically evaluated, in order to put PCDD/F emissions in perspective. It is concluded that the dioxins load of cement dust is unusually low, following the low carbon in raw materials, the use of natural gas as a fuel and the absence of waste incineration. Also the production of iron by direct reduction of ore is a low dioxins process; dioxin loads in dust are as usual - correlated with the presence of catalytic metals. Loss on ignition and chlorine are anti-correlated with the main earth elements and with sulphur oxides.

Advances in molecular imaging for diagnosis of digestive tract cancers

Digestive tract cancers are common cancer types and have high incidence and mortality. Currently available diagnostic methods have some limitations that make an early and accurate diagnosis and prompt treatment difficult. Molecular imaging, which has been formally defined as visualization, characterization and measurement at the molecular level instead of the anatomic level, significantly increases the sensitivity and specificity of cancer detection. Several modalities have been utilized for molecular imaging in digestive tract cancers, such as endoscopy, scintigraphy (PET/SPECT), magnetic resonance imaging (MRI), and ultrasound (US). Antibodies, peptides, and aptamers are classes of molecular probes that have been extensively used as affinity ligands. After being conjugated with various labels such as radioisotopes, fluorophore, supermagnetic or paramagnetic metals and microbubbles, the probes can specifically target tumor cells and stroma and are used with imaging modalities to detect cancers. Molecular imaging is a methodology for not only the early detection of cancer, but also the judgment of tumor staging and the guidance of therapy. With the development of new instrument and probes, as well as multi-modal platforms, molecular imaging has been gradually perfected and taken from bench to bedside, bringing opportunities for early, accurate and comprehensive diagnosis of digestive tract cancers.

Affinity peptide developed by phage display selection for targeting gastric cancer

AIM: To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.

METHODS: A peptide screen was performed by biopanning the PhD-12 phage display library, clearing non-specific binders against tumor-adjacent normal appearing gastric mucosa and obtaining selective binding against freshly harvested gastric cancer tissues. Tumor-targeted binding of selected peptides was confirmed by bound phage counts, enzyme-linked immunosorbent assay, competitive inhibition, fluorescence microscopy and semi-quantitative analysis on immunohistochemistry using different types of cancer tissues.

RESULTS: Approximately 92.8% of the non-specific phage clones were subtracted from the original phage library after two rounds of biopanning against normal- appearing gastric mucosa. After the third round of positive screening, the peptide sequence AADNAKTKSFPV (AAD) appeared in 25% (12/48) of the analyzed phages. For the control peptide, these values were 6.8 ± 2.3, 5.1 ± 1.7, 3.5 ± 2.1, 4.6 ± 1.9 and 1.1 ± 0.5, respectively. The values for AAD peptide were statistically significant (P < 0.01) for gastric cancer as compared with other histological classifications and control peptide.

CONCLUSION: A novel peptide is discovered to have a specific binding activity to gastric cancer, and can be used to distinguish neoplastic from normal gastric mucosa, demonstrating the potential for early cancer detection on endoscopy.

Differential placental hormone gene expression during pregnancy in a transgenic mouse containing the human growth hormone/chorionic somatomammotropin locus

The human (h) growth hormone/chorionic somatomammotropin (GH/CS) gene locus presents a unique model to gain insight into the molecular mechanisms that have allowed a closely related family of genes to be expressed in two distinct cell lineages/tissues: pituitary somatotrophs and placental syncytiotrophoblasts. However, studies of external factors that regulate gene expression have been somewhat limited by (i) a lack of human cell lines expressing endogenous GH or CS appropriately; and (ii) the fact that the GH/CS locus is unique to primates and thus does not exist in rodents. In the current study, a transgenic (171 h GH/CS-TG) mouse was generated containing the intact hGH/CS gene cluster and hGH locus control region (LCR) in a 171-kilobase DNA fragment. Pituitary and placental-specific expression of hGH/CS RNA was detected at embryonic day (E) 18.5. Immunostaining of hGH was seen in somatotrophs of the anterior pituitary beginning in late gestation. The presence of hCS protein was detected in the placental labyrinth in trophoblasts functionally analogous to the syncytiotrophoblast of the chorionic villi. This pattern of gene expression is consistent with the presence of essential components of the hGH/CS LCR. Transcript levels for hCS-A, hCS-B and placental hGH-variant increased in 171 hGH/CS-TG placenta during gestation (E11.5-E18.5), as previously observed in human placental development. Throughout gestation, hCS-A RNA levels were proportionately higher, accounting for 91% of total CS RNA by E18.5, comparable to term human placenta. Finally, the previous correlation between the transcription factor AP-2alpha and hCS RNA expression observed in developing primary human cytotrophoblast cultures, was extended to pregnancy in the 171 hGH/CS-TG mouse. The 171 hGH/CS-TG mouse thus provides a model to investigate hGH/CS gene expression, including in pregnancy.

PCDD/F concentrations of agricultural soil in the vicinity of fluidized bed incinerators of co-firing MSW with coal in Hangzhou, China

The concentrations of 17PCDD/F congeners as well as tetra- to octa-homologues were determined in 33 soil samples collected within a radius of 7 km from a municipal solid waste (MSW) incineration plant that is equipped with three fluidized bed incinerators (FBIs) of co-firing MSW with coal in Hangzhou, China. The total PCDD/F concentrations ranged from 0.39 to 5.04 pg I-TEQ g(-1) (54-285 pg g(-1)), with an average and a median value of 1.22 and 0.84 pg I-TEQ g(-1) (105 and 86 pg g(-1)), respectively. A systematic decrease of PCDD/F levels was observed with the increasing distances and with the decreasing downwind frequencies from the plant. The comparisons of homologue and congener patterns and multivariate analysis of soil and flue gas samples strongly indicated that most of the soil samples were influenced by the FBIs. Apart from the incineration plant, historical PCDD/F emissions of hazardous waste incinerator (HWI) and motor vehicles as well as the application of 1,3,5-trichloro-2-(4-nitrophenoxy) benzene (CNP) seemed to play an important role in soil samples adjacent to these potential sources.

Characteristic of polychlorinated dibenzo-p-dioxins and dibenzofurans in fly ash from incinerators in china

Fly ash from municipal solid waste (MSW), medical waste (MW) and electrical power plant (EPP) incinerators were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The study showed that the PCDD/F levels in fly ash were EPP<MSW<MW. The homologue profiles of PCDD/Fs in fly ash produced from waste incinerators were similar. However, the homologue profiles of PCDD/Fs in fly ash from electrostatic precipitator (ESP) of electrical power plant were different from that from waste incinerator. The strong correlation was found between the concentration of 2,3,4,7,8-PeCDF and the I-TEQ value of fly ash regardless of the different fly ashes sources.

Effects of calcium-based sorbents on PCDD/F formation from pentachlorophenol combustion process

Calcium-based sorbents are widely employed to reduce the acidic gases emission from combustion processes, and also have effects on trace organic pollutants formation and emission. Batch experiments were conducted to investigate the effects of calcium-based sorbents on pentachlorophenol (PCP) forming PCDDs/Fs during high temperature combustion processes. The results indicated that highly chlorinated PCDD/F homologues were the predominant dioxin products from PCP thermo decomposition, and only minor increasing of PCDDs happened when Ca/Cl ratio was lower than 1, while a major jump occurred when Ca/Cl ratio increased from 1 to 2. The CaO addition clearly promoted the production of all chlorinated dibenzo-p-dioxins homologue and 4-7DFs homologue. Comparison of total PCDD/F emission and its I-TEQ for three different calcium-based sorbents addition (CaO, CaCO3, basic fly ash) indicated that CaO and fly ash containing CaO had almost the same promotion effects on PCDDs/Fs originated from PCP, while CaCO3 inhibit PCDD/F formation greatly with inhibition efficiency up to 70%. Such effects may be partly proved by the observed clearly different micro-surface structures of their reaction residues. The mechanism of CaO on condensation and dechlorination reactions for PCP forming PCDDs and acid-base interaction were proposed to speculate the promotion effects of CaO, and the reaction precedence was used to speculate the inhibition effects of CaCO3 on PCDDs/Fs originated from PCP. The results of the present paper might be useful for the industrial application of calcium-based sorbents to control PCDD/F emission.

Degradation of PCDD/Fs by mechanochemical treatment of fly ash from medical waste incineration

The potential of mechanochemical treatment (MC) to degrade PCDD/Fs contained in fly ash was tested via grounding with and without calcium oxide (CaO) under atmospheric pressure. Three types of fly ash collected from medical waste incineration were compared, originating either from rotary kiln fluidized bed multi-stage incinerator using activated carbon spray (FA1, FA2), or a simple stoker incinerator without activated carbon spray (FA3). In test I: CaO to FA1 mixed at ratio of 6-60% was milled at rotational speed of 350 rpm; in test II: FA2 and FA3 without CaO were milled at rotational speed of 400 rpm. The duration of the tests was 2h. The results from the present study indicate that (1) under two test conditions of with and without CaO, PCDD/Fs contained in real fly ash both can be degraded by mechanochemical treatment, (2) under condition of blending with CaO, the degradation efficiency of PCDD/Fs increased with increasing ratio of CaO, (3) the degradation efficiency of PCDD/Fs may increase with rotational speed increasing and (4) the destruction and dechlorination are major mechanism for PCDD/Fs degradation. These results show that mechanochemical treatment is a high potential technology for PCDD/Fs degradation in fly ash.

P13 of Leucania separata multiple nuclear polyhedrosis virus affected the polyhedra and budded virions yields of AcMNPV

p13 gene was first described by our laboratory in Leucania separata multiple nuclear polyhedrovirus (Ls-p13, ORF114) back to 1995. However, the functions of Ls-P13 and its reported homologues remained unknown. In order to probe the function of Ls-P13, recombinant Autographa californica nucleopolyhedroviruses (rAcMNPVs) were constructed to express Ls-P13 in the Sf9 cells at early, late or early/late phase. Observations of microscope showed that the expression of Ls-P13 could decrease the yield of AcMNPV polyhedra in Sf9 cells, and early expressed Ls-P13 had stronger inhibition efficiency than that of the late expressed. Results of flow cytometry also indicated that Ls-P13 decreased the yield of AcMNPV polyhedra while increased those of budded virions (BVs) in Sf9 cells, but the efficacy was lost when its leucine zipper-like domain was mutated. Ls-P13 is a transmembrane protein, which was early located in the nucleus and late mainly in the cytoplasm membrane at 48 h. When its transmembrane domains were deleted, Ls-P13 distribution was dramatically diverted from cytoplasm membrane to nucleus, its corresponding efficacy on polyhedra yield was further increased while that on BVs was slightly weakened. Bioassay results indicated that Ls-P13 accelerated the larvae-killing rate. The mechanism might be that Ls-P13 increased BV yield.

Micro-reactors for PET tracer labeling

Miniaturization of PET radiosynthesis devices (micro-reactors or microfluidic systems) is an emerging area that has the potential to deliver many advantages, such as more efficient use of hot-cell space for production of multiple radiotracers; use of less non-radioactive precursor for saving precious material and a reduced separation challenge; highly controlled, reproducible and reliable radiotracer production; and cheap, interchangeable, disposable and quality-assured radiochemistry processors. Several 'proof of principle' examples along with basics of micro-reactor flow control, mixing principle and design, and device fabrication are discussed in this chapter.

Evaluation of PCDD/Fs emission from fluidized bed incinerators co-firing MSW with coal in China

The levels and homologue profile of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from stack gas of three typical fluidized bed incinerators co-firing municipal solid waste (MSW) with Chinese coal were measured. The PCDD/Fs emission was in the range of 0.0054-0.1961 ng I-TEQ/N m(3). Comparison of PCDD/Fs detection results by HRGC/HRMS and HRGC/LRMS suggested that it was feasible to detect fly ash with high PCDD/Fs concentration by HRGC/LRMS. Several factors on PCDD/Fs emission were discussed. The primary reason for the lower PCDD/Fs emission was the inhibition mechanism of relatively high sulfur in feeding coal on PCDD/Fs formation. The emission results also showed that there was no directly correlation between PCDD/Fs levels and CO, O(2) and HCl concentration in flue gas. It was estimated that about 0.1034 g I-TEQ was annually emitted to atmosphere from the tested three MSW incinerators (total daily treatment capacity is 800 tonnes MSW).

Treatment of Short Gut Syndrome With Early Living Related Small Bowel Transplantation

AIM

To investigate the results of treating short bowel syndrome with an early living related small bowel transplantation (SBT).

METHODS

A 17-year-old boy with a 20-cm-long residual intestine due to necrotic volvulus received an early living related SBT from his mother. Donor-specific blood transfusion was performed for 8 weeks before transplantation, each time for 50 mL every week. Cytomegalovirus status in both donor and recipient was negative. A 160-cm distal ileal segment was removed from the donor. The graft ilecolic artery and vein were anastomosed to the recipient's infrarenal aorta and caval vein. The proximal end of the graft was anastomosed end-to-end to the residual recipient jejunum; the distal anastomosis, between the distal end of the graft and transverse colon. An ileostomy was also performed. Immunosuppression, infection prophylaxis, and antithrombotic and nutrition support were given postoperatively.

RESULTS

The donor had an uneventful recovery. No technical complications were observed. The recipient was alive and well at 31 weeks after the operation. No graft rejection or infection was observed. He was off TPN 8 weeks after the operation and took low-fat food. The D-xylose test in the recipient was almost normal.

CONCLUSIONS

Early living related small intestine transplantation is a good treatment for short bowel syndrome.

[Construction of recombinant plasmid pIRES2-EGFP/CCK and its expression in vivo and in vitro]

OBJECTIVE

To construct eukaryotic expression plasmid of porcine CCK gene pIRES2-EGFP/ CCK and express it in COS-7 cells and hamsters.

METHODS

The aimed segments were obtained from intermediate vector pMD18-T/CCK by the method of restricted enzymatic resection and were inserted into a eukaryotic expression plasmid pIRES2-EGFP to construct a recombinant expression plasmid pIRES2-EGFP/CCK. The recombinant expression plasmid was transfected into COS-7 cells by liposome-mediated gene transfer method and observed through Fluorescence microscopy. The plasmid was injected into the skeletal muscle of hamsters directly to detect the expression of the recombinant plasmid in vivo.

RESULTS

A recombinant eukaryotic expression plasmid pIRES2-EGFP/CCK was successfully constructed. Green fluorescent protein could be detected in the transfected COS-7 cells 24, 48, and 72 hours post transfection and the expression of green fluorescent protein reached its peak 72 h post transfection. The green fluorescent protein could be detected at the injection site on the 4th day post injection and the fluorescence intensity became stronger on the 14th day. The level of fluorescence became ever stronger on the 42nd day. No expression of green fluorescence was detected in the control group.

CONCLUSION

Porcine CCK cDNA eukaryotic expression plasmid pIRES2-EGFP/CCK has been successfully constructed and expressed in mammal cells COS-7 and hamster in vivo. The research paved the way for cross immunity therapy of hamster pancreatic carcinoma.

Efficient induction of cytotoxic T lymphocytes specific to hepatocellular carcinoma using HLA-A2-restricted MAGE-n peptide in vitro

MAGE-n is a new member of MAGE gene family and has been demonstrated closely associated with hepatocellular carcinoma (HCC). In this study, MAGE-n-derived peptide-specific cytotoxic T lymphocytes (CTL) were induced from the peripheral blood mononuclear cells of healthy donors by multiple stimulations with HLA-A2-restricted MAGE-n peptide-pulsed T2 cells. The induced CTLs exhibited specific lysis against T2 cells pulsed with the peptide and HLA-A2+ HCC cells expressing MAGE-n, while HLA-A2+ HCC cell lines that did not express MAGE-n could not be recognized by the CTLs. The peptide-specific activity was inhibited by anti-MHC class I monoclonal antibody. These results suggested the MAGE-n peptide could be a potential target of specific immunotherapy for HLA-A2 patients with HCC.

Structural genomics efforts at the Chinese Academy of Sciences and Peking University

Structural genomics efforts at the Chinese Academy of Sciences and Peking University are reported in this article. The major targets for the structural genomics project are targeted proteins expressed in human hematopoietic stem/progenitor cells, proteins related to blood diseases and other human proteins. Up to now 328 target genes have been constructed in expression vectors. Among them, more than 50% genes have been expressed in Escherichia coli, approximately 25% of the resulting proteins are soluble, and 35 proteins have been purified. Crystallization, data collection and structure determination are continuing. Experiences accumulated during this initial stage are useful for designing and applying high-throughput approaches in structural genomics.

Superantigen-SEA gene modified tumor vaccine for hepatocellular carcinoma: An in vitro study

AIM: To construct an eukaryotic superantigen gene expression vector containing the recombinant gene of SEA and CD80 molecule transmembrane region (CD80TM), and to express staphylococcus enterotoxin A (SEA) on the membrane of hepatocellular carcinoma (HCC) cell to form a superantigen gene modified tumor vaccine for HCC.

METHODS: SEA and linker-CD80TM gene were amplified through PCR from plasmid containing cDNA of SEA and CD80. Gene fragments were then subcloned into the multiple cloning sites of retroviral vector pLXSN. Recombinant plasmid was transferred into HepG2 cells mediated with lipofectamine, positive clones were selected in culture medium containing G418. RT-PCR and indirect immunofluorescence studies confirmed that SEA was expressed specifically on HCC cell membrane. INFγ -ELISPOT study demonstrated that SEA protein was expressed on the membrane of HCC cells. Cytotoxicity of HepG2-SEA primed CTLs (SEA-T) was analyzed by ⁵¹Cr release assay. T cells cultured with rhIL-2 (IL-2-T) were used as control.

RESULTS: Restriction digestion and sequence analyses confirmed the correctness of length, position and orientation of inserted fusion genes. SEA was expressed on the surface of HepG2 cells, HepG2-SEA had strong stimulating effect on production of HepG2 specific CTL (P < 0.001). SEA-T had enhanced cytotoxicity to HepG2 cells (P < 0.05).

CONCLUSION: Tumor cell membrane expressed superantigen can be used to reinforce the immune effect of tumor cell vaccine for HCC, which provides a new method of the enhanced active immunotherapy for HCC.

Inhibition of the proliferation of smooth muscle cells from human coronary bypass vessels by vasonatrin peptide

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is known to be a key event in the development of atherosclerosis and restenosis. The present study examined the effect of a novel synthetic natriuretic peptide, vasonatrin peptide (VNP), on norepinephrine (NE)-induced proliferation of VSMCs from coronary bypass vessels. Human VSMCs were isolated from an internal mammary artery (IMA) and saphenous vein (SV) by explant culture and stimulated with NE. MTT assay and [3H] thymidine-incorporation were undertaken to analyze cell proliferation and radioimmunoassay was used to determine the level of intracellular cyclic 3',5'-guanosine monophosphate (cyclic GMP). NE (10(-8) - 10(-7) mol/l) had a mitogenic effect in human VSMCs from both SV and IMA. However, NE-stimulated proliferation of VSMCs from SV was greater than that from IMA. Furthermore, low concentration of NE (10(-10) mol/l) promoted cell growth in SV-derived cells but not in IMA-derived cells. VNP (10(-8) - 10(-6) mol/l) reduced NE-induced cell proliferation and increased intracellular cyclic GMP, which were abrogated by HS-142-1. In addition, the growth inhibition of VNP was mimicked by 8-bromo-cGMP. These results indicate that VNP has a significant inhibitory effect on NE-stimulated proliferation of human VSMCs from both IMA and SV, which is mediated by guanylate cyclase-linked receptors by increasing cyclic GMP.

Inhibition of the proliferation of smooth muscle cells from human coronary bypass vessels by vasonatrin peptide

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is known to be a key event in the development of atherosclerosis and restenosis. The present study examined the effect of a novel synthetic natriuretic peptide, vasonatrin peptide (VNP), on norepinephrine (NE)-induced proliferation of VSMCs from coronary bypass vessels. Human VSMCs were isolated from an internal mammary artery (IMA) and saphenous vein (SV) by explant culture and stimulated with NE. MTT assay and [3H] thymidine-incorporation were undertaken to analyze cell proliferation and radioimmunoassay was used to determine the level of intracellular cyclic 3’,5’-guanosine monophosphate (cyclic GMP). NE (10-8 - 10-7 mol/l) had a mitogenic effect in human VSMCs from both SV and IMA. However, NE-stimulated proliferation of VSMCs from SV was greater than that from IMA. Furthermore, low concentration of NE (10-10 mol/l) promoted cell growth in SV-derived cells but not in IMA-derived cells. VNP (10-8 - 10-6 mol/l) reduced NE-induced cell proliferation and increased intracellular cyclic GMP, which were abrogated by HS-142-1. In addition, the growth inhibition of VNP was mimicked by 8-bromo-cGMP. These results indicate that VNP has a significant inhibitory effect on NE-stimulated proliferation of human VSMCs from both IMA and SV, which is mediated by guanylate cyclase-linked receptors by increasing cyclic GMP.

[The construction and expression of a hepatocellular carcinoma-specific superantigen SEA (D227A) expression vector]

AIM

To construct the superantigen SEA (D227A) expression vector modulated by cis-acting element of AFP and express it specifically on AFP(+) hepatocellular carcinoma (HCC) cells.

METHODS

The enhancer and promoter of AFP gene, SEA (D227A) cDNA and linker-CD80tm were amplified by PCR. The gene segments mentioned above were cloned into the multiple cloning sites of retrovirus vector pLXSN to construct an attenuated superantigen expression vector pLXSN-SEA (D227A)-linker-CD80tm modulated by cis-acting element of AFP gene. AFP(+) or AFP(-) HCCs were transfected by the superantigen expression vector through lipofectamine mediation. SEA expression was detected by RT-PCR and indirect immunofluorescence staining.

RESULTS

Promoter, enhancer, SEA (D227A) and linker-CD80tm had been successfully cloned into the multiple cloning site of retrovirus vector pLXSN RT-PCR and indirect immunofluorescence assay were used to prove that SEA (D227A) could specifically express in the AFP(+) HCCs.

CONCLUSION

The successful construction and expression of hepatocellular carcinoma-specific superantigen SEA (D227A) gene expression vector lay the foundation for enhancing immunotherapy of hepatocellular carcinoma.

[Study on immunoreaction induced by DCs loaded with hepatocarcinoma antigen peptide in-vitro]

AIM

To investigate the potency and antitumor effect of specific cytotoxic T lymphocytes induced by hepatocarcinoma antigen peptide EPVTKAEML-loaded dendritic cells (DCs).

METHODS

The healthy donors of HLA-B7 genotype were selected by PCR-SSP. Isolated and cultured DCs from HLA-B7 donors' spleen tissues were loaded with the peptide EPVTKAEML from hepatocarcinoma cell line HHCC. The specific CTL reaction and inhibitory effect of anti-HLA-I molecule mAb on CTL cytotoxicity were detected in-vitro by (51)Cr-release assay.

RESULTS

4 donors with HLA-B7 genotype were found. Their spleen T lymphocytes could be induced to proliferate and differentiate into specific CTLs by DCs loaded with the peptide. Antibody-blocking test demonstrated that the cytotoxity of CTLs was strictly limited by MHC-I molecule.

CONCLUSION

EPVTKAEML-loaded DCs can induce efficient and specific antitumor immune reaction in-vitro.

[Construction of VEGF eukaryotic expression vector and its expression in endothelial cells and cardiac myocytes in-vitro]

AIM

To study the feasibility of VEGF165 gene transfection to endothelial cells and cardiac myocytes in-vitro.

METHODS

The VEGF165 DNA fragment was inserted into a green fluorescent protein fusion vector, which was then transfected into endothelial cells and cardiac myocytes with lipofectamine.

RESULTS

The endothelial cells and cardiac myocytes were successfully transfected with pIRES2-EGFP-hVEGF165 gene, which was confirmed by fluoroscopy and immunohistochemistry.

CONCLUSION

VEGF can be expressed stably in the endothelial cells and cardiac myocytes, which might be useful for the gene therapy of myocardial ischemia.

Construction of a regulable gene therapy vector targeting for hepatocellular carcinoma

AIM: To construct a gene modified hepatocellular carcinoma (HCC) specific EGFP expression vector regulated by abbreviated cis-acting element of AFP gene.

METHODS: The minimal essential DNA segments of AFP gene enhancer and promoter were synthesized through PCR from Genome DNA of HepG2 cells. Gene fragments were then cloned into the multiple cloning site of non-promoter EGFP vector pEGFP-1. Recombinant plasmid was transferred into positive or negative AFP cell lines by means of lipofectamine. The expression of EGFP was tested by fluorescence microscope and flow cytometry. The effect of all-trans retinoic acid (ATRA) on the expression of EGFP was tested in different concentrations.

RESULTS: By the methods of restriction digestion and sequence analyses we confirmed that the length, position and orientation of inserted genes of cis-acting element of AFP were all correct. The transcription of EGFP was under the control of AFP cis-acting element. The expressing EGFP can only been detected in AFP producing hepatoma cells. The expression rate of EGFP in G418 screened cell line was 34.9% ± 4.1%. 48 h after adding 1 × 10^-7 M retinoic acid, EGFP expression rate was 14.7% ± 3.5%. The activity of AFP gene promoter was significantly suppressed by addition of 1 × 10^-7 M retinoic acid (P < 0.05, P = 0.003, t = 6.488).

CONCLUSION: This recombinant expression vector can be used as a gene therapy vector for HCC. The expression of tumor killing gene will be confined within the site of tumor and the activity of which can be regulated by retinoic acid.