Profilin 1, negatively regulated by microRNA-19a-3p,serves as a tumor suppressor in human hepatocellular carcinoma

Profilin 1 (PFN1) is a critical actin-regulatory protein; however, its functional role in hepatocellular carcinoma (HCC) progression remains to be further elucidated. In the present study, we observed that the expression levels of PFN1 were significantly decreased in HCC tissues and cell lines. Low PFN1 expression was significantly correlated with aggressive clinicopathological characteristics and poor prognosis of HCC patients. Further in vitro experiments demonstrated that overexpression of PFN1 remarkably inhibited the proliferation, migration, invasion and EMT of HCC cells. Moreover, we also found that PFN1 was a direct target gene of miR-19a-3p, and in HCC tissues, and there was a significantly inverse correlation between PFN1 mRNA and miR-19a-3p expression. Collectively, our results showed that PFN1 functions as a tumor suppressor in HCC, and might serve as a diagnostic and therapeutic target for HCC patients.     

Interactions between epidermal growth factor-mediated autocrine regulation and linoleic acid-stimulated growth of a human prostate cancer cell line.

Human prostate cancer (PC) cell lines possess epidermal growth factor (EGF) receptors and secrete EGF-related polypeptides. We used an EGF receptor-blocking antibody (anti-EGF.R) to demonstrate a functional autocrine loop, as well as the interaction between this and the effects of linoleic acid (LA), an omega-6 fatty acid, on PC cell growth. The anti-EGF.R competed effectively with [125I]EGF for receptors on DU145 PC cells, and on a high-passage DU145 variant (DU145M); when added to the culture medium, it suppressed both DU145 and DU145M cell growth in a dose-dependent manner. LA, a precursor for eicosanoid synthesis, had little effect on DU145 cell growth rate but stimulated DU145M growth in a concentration-related manner over a range of 0.25-2.0 micrograms/ml. anti-EGF.R (10(-9) M) caused suppression of LA-stimulated growth of DU145M cells in serum-free medium, which was prevented by the addition of 2 nM EGF. We conclude that an EGF.R-mediated autocrine loop is involved in PC cell growth regulation and that at least one site of action may be the synthesis of eicosanoids from their LA precursor.     

Presence of hepatitis B surface antigen mutant G145R DNA in the peripheral blood leukocytes of the family members of an asymptomatic carrier and evidence of its horizontal transmission

An asymptomatic carrier and all six of his family members were detected positive for HBV DNA in their peripheral blood leukocytes (PBL), by polymerase chain reaction. Direct sequencing of the amplified DNA revealed that the HBV DNA from the carrier and his wife was of subtype ayw. Interestingly, the amplified HBV DNA from the five other members of the family was found to be not only of subtype adw but also contained G to A mutation at nucleotide position 587. This indicates the presence of established vaccine escape mutant of the virus (G145R) and suggests two different sources of infection within the family. Southern blot hybridization of EcoR1 digested DNA from PBL indicated presence of HBV DNA, integrated into cellular DNA and also in the form of free viral DNA. The study not only establishes the persistence of surface mutant G145R HBV DNA, within the PBL of HBsAg negative individuals from the non-vaccinated random population, but also suggests possible horizontal transmission of the mutant among the family members although none of the family members has received immunoprophylaxis against HBV or had clinically apparent disease or any other known risk factors of HBV infection. As all of them were seronegative for HBsAg/antiHBc, the presence of G145R mutant in the PBL signaled possibility of spread of the vaccine escape mutant virus by blood transfusion, unsafe injection practices or through sexual root.     

Biosynthesis of two stage-specific membrane proteins during transformation of Plasmodium gallinaceum zygotes into ookinetes

We have studied the synthesis and expression of surface proteins in zygotes of Plasmodium gallinaceum during their transformation to mature ookinetes. The cells were biosynthetically labelled in vitro using [35S]methionine and proteins were immunoprecipitated with rabbit anti-ookinete serum or monoclonal antibodies. Early zygotes (approx. 2 h post-gametogenesis and fertilization) synthesized and expressed on their surface a protein of Mr 26 000 as observed under reducing conditions on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) (31 000 under non-reducing conditions) and continued to do so for 8-10 h; thereafter synthesis of the Mr 26 000 protein declined and little or none was synthesized in the mature ookinetes (greater than 20 h post-gametogenesis). Between 3-5 h post-gametogenesis, zygotes also began to synthesize a protein of Mr 28 000 (34 000 under non-reducing conditions). Synthesis and expression of this surface protein continued throughout development; and the Mr 28 000 protein was the predominant surface protein synthesized by the mature ookinete. Mr 26 000 and Mr 28 000 proteins have been designated earlier as PgO-1 and PgO-2 respectively (Carter and Kaushal, Mol. Biochem. Parasitol. (1984) 13, 235-241). Neither protein was synthesized in the gametocytes prior to gametogenesis. Both proteins could be labelled with [3H]glucosamine or [3H]mannose. When zygotes were incubated with [3H]palmitic acid both PgO-1 and PgO-2 bound fatty acids in covalent linkage. The two proteins do not otherwise appear to be structurally related. They were differentially immunoprecipitated by different monoclonal antibodies and gave rise to distinct patterns of peptides following digestion with proteases such as Staphylococcus aureus V-8, trypsin and chymotrypsin.     

In vitro evidence for participation of DEC-205 expressed by thymic cortical epithelial cells in clearance of apoptotic thymocytes

Binding of apoptotic cells was compared after incubation of thymocytes with two clones of murine thymic stromal cells to which CD4(+)/CD8(+) thymocytes attach. With the BA/10, but not the BA/2, clone, thymocytes with apoptotic morphology were bound irreversibly. These tightly bound thymocytes were further identified as apoptotic in terms of active caspase-3 and DNA fragmentation assayed in situ. FACS analysis indicated that the apoptotic thymocytes are at an early double-positive stage and results with mice mutant for the Fas gene showed that the Fas-Fas ligand system is not involved. Comparison of BA/10 and BA/2 cells showed that the former, but not the latter, can be induced to express CDR-1 antigen which is characteristic of cortical epithelial thymic stroma and constitutively express DEC-205, a surface protein common to cortical thymic epithelium and dendritic cells. Antibody NLDC-145 that is specific for the DEC-205 protein strongly reduced the number of stromal cells with bound apoptotic thymocytes. Preincubation of thymocytes in dexamethasone dramatically increased the number of bound apoptotic cells, indicating that the thymic cortical epithelial cells can participate in clearance of apoptotic thymocytes through involvement of DEC-205.     

MADP-1基因对前列腺癌细胞系DU145体外生长的影响

[目的]探讨新基因MADP-1对雄激素非依赖性前列腺癌细胞系DU145增殖的影响,了解其功能.[方法]采用脂质体和绿色荧光蛋白基因标记的质粒载体pIRES-hrGFP-1α,将MADP-1基因导入前列腺癌细胞系DU145中.应用荧光显微镜、流式细胞仪分析和分选术及细胞生长曲线动态观察MADP-1基因对DU145细胞系的影响.[结果]转染细胞在荧光显微镜下显示绿色荧光.转染MADP-1基因组细胞生长加速,与转染空载体组及对照组相比,有显著差异(P＜0.05).[结论]新基因MADP-1在体外具有促进前列腺癌细胞系DU145增殖的作用.     

Phase I pharmacokinetic trial of the selective oral epidermal growth factor receptor tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839) in Japanese patients with solid malignant tumors.

BACKGROUND: This phase I dose-escalating study investigated the tolerability and toxicity of the selective epidermal growth factor receptor tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839) in Japanese patients with solid tumors. Thirty-one patients were included. PATIENTS AND METHODS: Patients initially received a single oral dose of gefitinib followed by 10-14 days of observation. Oral gefitinib was subsequently administered on 14 consecutive days, every 28 days. Dose escalation was from 50 mg/day to a maximum of 925 mg/day or dose-limiting toxicity (DLT). RESULTS: Most adverse events were mild (grade 1/2); the most frequent were an acne-like rash and gastrointestinal effects. Two of six patients at 700 mg/day had DLT; no further dose escalation occurred. C(max) was reached within 3-7 h and exposure to gefitinib increased with dose. Mean terminal half-life following multiple dosing was 50.1 h (range 27.8-79.7 h). A partial response (duration 35-361 days) was observed in five of the 23 patients with non-small-cell lung cancer over a range of doses (225-700 mg/day), and seven patients with a range of tumors had disease stabilization (duration 40-127 days). CONCLUSIONS: In conclusion, gefitinib showed a favorable tolerability profile in Japanese patients. The safety profile, pharmacokinetic parameters and antitumor activity observed in our study are comparable to those observed in patients from the USA and Europe.     

人巨细胞病毒UL145基因在先天感染患儿临床株中的多态性研究

目的：研究人巨细胞病毒（HCMV）UL145序列在先天感染患儿临床株中的基因多态性，探讨HCMV基因多态性与先天感染引起的不同临床症状之间的关系。方法：对16株临床低传代分离株和15株未传代临床株的HCMV临床标本分别进行UL145全序列PCR扩增，对PCR扩增阳性的31例标本进行序列测定及分析，并且与9株已在GenBank递交的HCMVUL145序列进行比较分析。结果：序列分析结果表明31株HCMV临床株的UL145基因是高度保守的。所有临床株的HCMVUL145开放阅读框架均为393bp，编码蛋白含有130个氨基酸。所有临床株的核苷酸同源率为95．9％～100％，编码蛋白的同源率为97．7％～100％。临床症状不同的患儿其HCMVUL145基因及其编码蛋白具有相似的结构。所有先天感染患儿临床株的UL145编码蛋白具有蛋白激酶C（PKC）磷酸化功能位点和酪蛋白激酶（CK2）磷酸化功能位点。结论：HCMVUL145基因在临床株中是高度保守，未发现其与HCMV先天感染不同临床症状间存在明显的关系。HCMV UL145基因的高度保守性在先天感染中具有重要作用。     

胰腺导管腺癌中microRNA-21与TGF-β1信号通路相关

目的：对胰腺导管腺癌样本进行基因分析,筛选与胰腺导管腺癌相关的microRNA(miRNA),并初步分析目标miRNA与胰腺癌转化生长因子-β1(TGF-β1)信号通路的相关性。方法：收集在海南省中医院住院的胰腺导管癌患者术前外周静脉血血清标本19份,健康体检人群的外周静脉血血清标本21份作为非胰腺导管癌对照组。利用GCBI(Gene-Cloud Biotechnology Information)数据平台筛选与胰腺导管腺癌样本有关的基因并对其进行生物信息学分析,将筛选出的基因作为研究对象,用real-time PCR和蛋白质印迹法验证该基因在胰腺导管腺癌中的表达。通过改变胰腺导管腺癌细胞中该基因的表达水平观察其与TGF-β1之间的关系。结果：通过聚类分析和基因功能富集分析筛选出miRNA-21为胰腺导管癌相关基因。MiRNA-21在胰腺导管腺癌患者体内高表达。在miRNA-21过表达的PANC-1细胞中,TGF-β1表达受到抑制;但当miRNA-21的表达受到抑制时,TGF-β1的表达明显上升。结论：MiRNA-21在胰腺导管腺癌患者体内高表达,可调控TGF-β1的表达,从而参与胰腺导管腺癌的发生发展。