脂质体包裹MUC2反义核酸抑制胃癌细胞增殖的初步探讨

背景与目的：我们前期研究发现粘蛋白MUC2在胃癌组织中的表达与肿瘤的生物学行为密切相关。本研究拟观察MUC2反义脱氧寡核苷酸(antisense oligodeoxynucleotide,ASODN)对人胃癌细胞SGC7901生长抑制作用。方法：应用硫代磷酸修饰的MUC2 ASODN经阳离子脂质体包裹后转染入SGC7901细胞,采用MTT法、形态学观察测定MUC2 ASODN对SGC27901细胞的增殖抑制作用,免疫组化检测细胞中MUC2和p16蛋白的表达情况。结果：不同浓度ASODN均能抑制SGC7901细胞的增殖,在48h抑制作用最强,0．5μmol／L ASODN对细胞的抑制率为55％,随时间延长抑制作用逐渐减弱。SGC7901细胞转染MUC2 ASODN后,与对照组相比,光镜下观察到细胞数量减少、体积变小、核分裂明显减少、可见较多的坏死。透射电镜下见线粒体肿胀、细胞内脂滴增多、髓样结构、染色质边集等。免疫组化SP法染色显示转染ASODN后,SGC7901细胞MUC2蛋白表达水平明显降低,p16蛋白表达明显增强。结论：使用人工合成MUC2 ASODN能有效抑制人胃癌细胞SGC790l的增殖。     

Anti-Tumor Effect of Curcumin on Human Cervical Carcinoma HeLa Cells In Vitro and In Vivo

Objective: To investigate the anti-tumor effect of curcumin on human cervical carcinoma HeLa cells in vitro and in vivo. Methods: (1) Human cervical carcinoma cell line HeLa was cultured in vitro. HeLa cells were treated with 5-50 μmol/L curcumin for 24. 48, 72 h and the growth inhibition rates of HeLa cells were measured by MTT method. Cell apoptosis was inspected by electron microscopy and flow cytometry (FCM). (2) A transplanted tumor model by injecting HeLa cells into subcutaneous tissue of BABL/C mice was established and its growth curve was measured. 30 BABL/C mice with tumors were divided into 2 groups at random and 0.2 ml saline or 0.2 ml 250 μmol/L curcumin was injected into abdominal cavity respectively once everyday and lasted for ten days. The changes of tumor volume were measured continuously and tumor inhibition rate was calculated. At last the expressions of caspase-3 and bax protein in transplanted tumors were detected by immunohistochemistry. Results: (1) Curcumin inhibited the proliferation of Lela cells on a dose-depending manner. Apoptosis of cells could be observed by FCM. Partial cells presented the characteristic morphological changes of apoptosis under electron microseope. (2) When 1×107 HeLa cells were inoculated for each mouse, 100% of the mice developed growing tumors after seven days. An inhibition effect was observed in treatment group, and the inhibition rate of curcumin was 74.33%. The expressions of caspase-3 and bax in the transplanted tumors were increased in curcumin group. Conclusion: Curcumin is effective as an anti-cancer drug not only in vitro but also in vivo.     

ADENOVIRUS－MEDIATED P53 GENE TRANSFER INCREASES THE THERMOSENSITIVITY OF HUMAN GASTRIC CARCINOM ACELL LINES （IN VITRO AND IN VIVO）

Objective: To investigate the effect of adenovirus-mediated p53 (Adp53) transfer on thermosensitivity of human gastric carcinoma cell lines (BGC823). Methods: Two human gastric carcinoma cell lines with different p53 status, BGC823-wtp53 cell (abbreviate W) bearing the wilt-type p53 and BGC823-mutp53 cell (abbreviate M) bearing the mutant p53, were cultured with DMEM medium and were infected with Adp53 at a viral multiplicity of infection of 100 (1:100MOI) for 48h before heating. Cell cycle redistribution and apoptosis of two human gastric carcinoma cell lines in 24h at 37°C after heat treatment at 42°C for 2h or 43°C for 0.5h were analyzed by flow cytometry. Relative tumor volume growth curves were used in a nude mouse tumor model of the two cell lines following hyperthermia at 43 C for 0.5h after 48h intratumoral injection of 1×108 pfu of Adp53 to evaluate thermoenhancemet effectin vivo. Results:In vitro study showed that both W and M cells infected with Adp53 and treated with heating had strong arrest in G2 (after heating at 42°C for 2h, 34.0% of original population for W cells and 25.3% of original population for M cells) and produced obvious apoptotic response. The apoptosis rate showed 230% increased (for W cells) and 110% increase (for M cells) compared with heating only control.In vivo study showed that the growth of tumor of both W cells and M cells was significantly delayed by hyperthemia combining with Adp53 as compared to tumors receiving either treatment alone. Conclusion: This study demonstrated that Adp53 transfer increased cellular apoptosis and thermo- sensitivityin vitro and tumor thermosensitivityin vivo independent of cellular intrinsic p53 status. These results support the combined used of p53 gene therapy with hyperthermia in clinical trials. Foundation item: This work was supported by the National Natural Foundation of China (No. 39670234 ) Biography: ZHANG Shan-wen(1946–), male, professor, Department of Radiotherapy, Peking University School of Oncology, majors in radiation oncology and gene therapy.     

Effects of Triptolide on Cell Proliferation and CXCR4 Expression in Burkitt＇s Lymphoma Raji Cells In Vitro

Objective： To investigate the inhibitory effects of triptolide on cell proliferation and CXCR4 expression in Burkitt＇s lymphoma cell line Raji cells. Methods： The effects of triptolide on the growth of Raji cells were studied by 3-（4, 5-Dimethyl-2-thiazolyl）-2, 5-diphenyl-2H-tetrazolium（MTT） assay. The effects of triptolide on CXCR4 expression on Raji cells were studied by flow cytometric analysis. Chemotaxis assays were performed to observe the effects of triptolide on migration of Raji cells towards recombinant human SDF-1α （rhSDF-1α） in vitro. Results： Triptolide inhibited the proliferation of Raji cells in a dose- and time-dependent way with a 24-h IC50 value of 43.06 nmol/L and a 36-h IC50 value of 25.08 nmol/L. Triptolide could downregulate the CXCR4 expression on Raji cells in a dose-dependent manner. Furthermore, chemotaxis assays showed that triptolide could block the migration of Raji cells to rhSDF-1α in vitro, and the inhibition was dose-dependent. Conclusion： Triptolide could inhibit the proliferation and migration of Raji cells in vitro. The underlying anti-tumor mechanism of triptolide might be related to the anti-proliferative effect and the blockage of SDF-1/CXCR4 axis.     

Anti-tumor effect and its mechanisms of ursolic acid on human esophageal carcinoma cell Eca-109 <Emphasis Type="Italic">in vivo</Emphasis>

Objective： To investigate the anti-tumor effect and possible mechanisms of ursolic acid on human esophageal carcinoma in vivo. Methods： Atransplanted tumor model by injecting Eca-109 cells into subcutaneous tissue of BALB/c nude mice was established. 40 nude mice bearing tumors were randomly divided into 4 groups and 0.2 ml saline or 0.2 ml ursolic acid （25-100 mg·kg^-1·d^-1） was injected into abdominal cavity respectively once everyday and lasted for fourteen days. The changes of tumor volume were measured continuously and tumor inhibition rate was calculated. The morphological changes of apoptosis were observed by electron microscope. The expressions of COX-2, bcl-2 and Bax protein in transplanted tumors were detected by immunohistochemistry. At last the PGE2 level of transplanted tumors was detected byradioimmunoassay. Results： Treatment of nude mice with 25, 50, or 100 mg·kg^-1·d^-1 of ursolic acid significantly inhibited the growth of the human esophageal carcinoma tumor in nude mice and induced Eca-109 cells apoptosis as demonstrated by electron microscopy analyses. The expressions of COX-2 and bcl-2 in the transplanted tumors were decreased in ursolic acid groups, while the Bax increased. The PGE2 level of transplanted tumors was decreased in ursolic acid groups with adose-relatedmanner. Conclusion： Ursolic acid has anti-tumor effects against human esophageal carcinoma cells in vivo, which are likely mediated via induction of tumor cell apoptosis and inhibition of COX-2 and PGE2.     

Effects of Various Factors on Proliferation Capacity and Cytotoxicity of Induced CIK of Patients with Tumor In Vitro

Objective： To evaluate effects of different factors on proliferation capacity and cytotoxicity of induced cytokine induced killer （CIK） cells in vitro, so as to provide experimental basis for cell therapy of CIK in tumor. Methods： Cytometry and MTT assay were used in detecting proliferation capacity and cytotoxicity of CIK. Results： The proliferation capacity and cytotoxicity of CIK in vitro were stronger in the group of low age and serum free medium than in the group of advanced age or serum medium. And the proliferation of CIK in vitro increased with time during a certain period of incubation. Furthermore, CIK had equal cytotoxicity to various tumor cells. Conclusion： Various factors might influence the proliferation capacity and cytotoxicity of CIK of tumor patients in vitro.     

Genetic mutations of <Emphasis Type="Italic">p53</Emphasis> and <Emphasis Type="Italic">k-ras</Emphasis> in gastric carcinoma patients from Hunan,China

This case–control study investigated the mutations in p53 and k-ras genes of 123 gastric carcinoma patients and 129 normal individuals from Hunan, China. By isolating genomic DNA from peripheral blood and employing polymerase chain reaction–single strand conformation polymorphism and DNA sequencing, the mutations of p53 exons-5, 6, 7, and 8 and k-ras were detected. The overall mutation frequency of p53 was 29.3%, and mutation was found in all four exons studied. The point mutations were predominant and among them, G:C→A:T was the highest (41.7%), followed by A:T→G:C (25%), G:C→C:G (11.1%), G:C→T:A (8.3%), and A:T→T:A (2.8%). The frameshift mutation was 11.1%. Mutations were detected in codons-131, 132, 133, 135, 149, 151, 162, 167, 173, 174, and 175 of exon 5, codons-193, 197, 213, and 215 of exon 6, codons-245, 246, 248, 249, and 270 of exon 7, and codons-271, 272, 273, and 282 of exon 8 of p53. The overall frequency of mutation in k-ras was 9.8%, mostly in codon-12 (91.7%) and in codon-13 (8.3%). There was no significant relationship between p53 and k-ras gene mutation in gastric carcinoma patients. Also, the relationships between p53 mutation and age, sex, smoking or drinking, and tumor metastasis were not significant. However, the patients with high/high-middle differentiated gastric carcinoma had a higher association with of p53 mutations. This study identified some novel p53 mutations in gastric cancer and showed mutation pattern and frequency of p53 and k-ras in the population of the central southern region of China.     

Cathepsin B inhibition interferes with metastatic potential of human melanoma: an <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis> study

Background  

Cathepsins represent a group of proteases involved in determining the metastatic potential of cancer cells. Among these are cysteinyl- (e.g. cathepsin B and cathepsin L) and aspartyl-proteases (e.g. cathepsin D), normally present inside the lysosomes as inactive proenzymes. Once released in the extracellular space, cathepsins contribute to metastatic potential by facilitating cell migration and invasiveness.     

Carcinogenesis of gastric endocrine cell carcinoma: analysis of histopathology and <Emphasis Type="Italic">p53</Emphasis> gene alteration

Background Endocrine cell carcinoma of the stomach is characterized by endocrine differentiation and aggressive biological behavior, and is frequently accompanied by an adenocarcinoma component. Because the carcinogenic pathway and genetic alterations remain unclear, we investigated the histogenesis of this tumor by histopathological and p53 gene analysis.Methods The materials were 68 gastric endocrine cell carcinomas and 30 carcinoid tumors, which were resected from 93 Japanese patients for histopathological and immunohistochemical investigation. We also analyzed the concordance of p53 mutational status between the associated adenocarcinoma and endocrine cell carcinoma components, using microdissection and direct sequencing techniques.Results An adenocarcinoma component was associated with 70.6% (48/68) of endocrine cell carcinomas, of which 42 (87.5%) were of well- to moderately differentiated type, while 36 of these 42 (85.7%) demonstrated histological continuity with the endocrine cell carcinoma components. Overexpression of p53 protein was observed in 58.8% (20/34) of cases. Common p53 mutational status between the two components was revealed in 73.3% (11/15) of cases analyzed. In contrast, carcinoid tumors did not exhibit p53 protein overexpression (0/15) or gene mutation (0/5).Conclusions These data suggest that gastric endocrine cell carcinomas predominantly arise from endocrine precursor cell clones occurring in preceding adenocarcinoma components (particularly the differentiated type), transforming into endocrine cell carcinoma during rapid clonal expansion under the influence of p53 gene alteration.     

Treatment of low-grade gastric MALT-lymphoma unresponsive to <Emphasis Type="Italic">Helicobacter</Emphasis> <Emphasis Type="Italic">pylori</Emphasis> therapy

The most favourable therapeutic strategy for gastric MALT-lymphoma not responding to Helicobacter pylori eradication still remains unclear, neither official guidelines nor randomised studies being available. We therefore performed a systematic review of the literature to evaluate the efficacy of different therapeutic approaches in these patients. Data regarding 315 patients were valuable, and lymphoma remission following the first therapeutic attempt was achieved in 90.1% cases. The most used therapy was radiotherapy (112 patients), followed by surgery (80 patients) and chemotherapy (68 patients), whilst a combination therapy was less frequent. Radiotherapy achieved a higher remission rate as compared to chemotherapy (97.3 vs. 85.3%; P = 0.007), being similar to surgery (97.3 vs. 92.5%; P = 0.2). No difference emerged when comparing lymphoma remission rate achieved by a single therapy with that of combined treatments (89.6 vs. 96.4%; P = 0.6). This is the first pooled-data analysis assessing the efficacy of different oncologic therapeutic approaches to treat gastric MALT-lymphoma unresponsive to H. pylori eradication. Radiotherapy seems to be the most suitable treatment in these patients.     

Triphala inhibits both <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis> xenograft growth of pancreatic tumor cells by inducing apoptosis

Background  

Triphala is commonly used in Ayurvedic medicine to treat variety of diseases; however its mechanism of action remains unexplored. This study elucidates the molecular mechanism of Triphala against human pancreatic cancer in the cellular and in vivo model.     

The immunomodulator PSK induces <Emphasis Type="Italic">in vitro</Emphasis> cytotoxic activity in tumour cell lines <Emphasis Type="Italic">via</Emphasis> arrest of cell cycle and induction of apoptosis

Background  

Protein-bound polysaccharide (PSK) is derived from the CM-101 strain of the fungus Coriolus versicolor and has shown anticancer activity in vitro and in in vivo experimental models and human cancers. Several randomized clinical trials have demonstrated that PSK has great potential in adjuvant cancer therapy, with positive results in the adjuvant treatment of gastric, esophageal, colorectal, breast and lung cancers. These studies have suggested the efficacy of PSK as an immunomodulator of biological responses. The precise molecular mechanisms responsible for its biological activity have yet to be fully elucidated.     

A novel circular invasion assay mimics <Emphasis Type="Italic">in vivo</Emphasis> invasive behavior of cancer cell lines and distinguishes single-cell motility <Emphasis Type="Italic">in vitro</Emphasis>

Background  

Classical in vitro wound-healing assays and other techniques designed to study cell migration and invasion have been used for many years to elucidate the various mechanisms associated with metastasis. However, many of these methods are limited in their ability to achieve reproducible, quantitative results that translate well in vivo. Such techniques are also commonly unable to elucidate single-cell motility mechanisms, an important factor to be considered when studying dissemination. Therefore, we developed and applied a novel in vitro circular invasion assay (CIA) in order to bridge the translational gap between in vitro and in vivo findings, and to distinguish between different modes of invasion.     

The Biology of <Emphasis Type="Italic">K-Ras</Emphasis> and <Emphasis Type="Italic">B-Raf</Emphasis> Mutations in Colorectal Cancer

Ras and Raf proteins are two major players in the MAP kinase pathway. They are crucial downstream regulators of multiple receptor tyrosine kinase-mediated cell growth, transformation, and maintenance of the malignant phenotype in human cancers. Mutations have been identified in K-Ras and B-Raf in patients with colorectal cancer. Clinical studies in colorectal cancers demonstrate that the therapeutic efficacy of cetuximab, a chimeric monoclonal antibody against epidermal growth factor receptor, depends on the presence of wild-type K-Ras. However, mutations in B-Raf do not predict cetuximab resistance. These observations have led to the use of K-Ras as a predictive biomarker, allowing clinicians to direct the therapy of cancer patients based on their K-Ras mutational status.