药用真菌抗肿瘤作用机制研究进展

药用真菌在抗肿瘤、免疫调节等方面作用明显且不良反应较小,然而,药用真菌活性成分与药理作用的关系及作用机理仍需进一步研究。     

药用真菌抗肿瘤作用机制研究进展

药用真菌在抗肿瘤、免疫调节等方面作用明显且不良反应较小,然而,药用真菌活性成分与药理作用的关系及作用机理仍需进一步研究.     

干扰素治疗肿瘤机制研究的进展

干扰素是一类具有广泛生物学活性的蛋白质,具有调节机体免疫功能、抗病毒、抗肿瘤等多种作用,是机体防御系统的重要组成部分。1957年,Isaacs和Lindermann首先发现了病毒干扰现象,即病毒感染细胞能产生一种细胞因子,作用于其他细胞干扰病毒的复制,因而命名为干扰素(interferons,     

六种天然皂苷抗肿瘤作用的研究进展

目前寻找高效低毒的天然植物成分是抗癌药物研究的重要方向。天然皂苷是存在于自然界的一类复杂的苷类化合物,具有抗肿瘤、抗炎、免疫调节等广泛的药理学活性。近年报道多种皂苷具有显著的抗肿瘤活性,其抗肿瘤作用和机制在不断深入研究中,天然皂苷有望成为一类抗癌新药。     

蚯蚓提取物抗肿瘤作用的研究进展

蚯蚓,又名地龙,是我国传统中药材之一,已有4000余年入药历史。蚯蚓可用于高血压、出血、溃疡、烧烫伤、癫痫等疾病的治疗。近年来蚯蚓提取物的抗肿瘤作用已引起广泛重视。从鲜蚯蚓中提取的蚯蚓提取物含有多肽、蛋白质及RNA、DNA、维生素等多种活性成分。近年来,蚯蚓提取物的抗肿瘤作用引起国内外学者的重视,成为目前研究的热点,本文旨在对蚯蚓提取物的抗肿瘤作用及其机制作一综述。1蚯蚓提取物概述蚯蚓提取物是从鲜蚯蚓中提取的活性成分,具有活血化瘀、清热解毒、提高机体免疫功能的作用,长期以来可用于细菌、病毒感染性疾病、免疫性疾病…     

六种天然皂苷抗肿瘤作用的研究进展

目前寻找高效低毒的天然植物成分是抗癌药物研究的重要方向。天然皂苷是存在于自然界的一类复杂的苷类化合物,具有抗肿瘤、抗炎、免疫调节等广泛的药理学活性。近年报道多种皂苷具有显著的抗肿瘤活性,其抗肿瘤作用和机制在不断深入研究中,天然皂苷有望成为一类抗癌新药。     

中药五加皮抗肿瘤活性成分的分离

背景与目的:分离中药五加皮抗肿瘤活性成分,确定其分子量,为抗肿瘤新药开发研制提供依据.材料与方法:采用3H-TdR掺入法测定五加皮有效成分对肿瘤细胞增殖反应的影响;经凝胶层析进一步分离五加皮抗肿瘤成分;用SDS-PAGE电泳、二次元电泳分离并确定其成分和分子量;经蛋白酶E和NaIO4处理分析了有效成分的化学组成.结果:经凝胶层析和SDS-PAGE电泳分析,我们从五加皮提取物(S200F2)中分离得到分子量约64kDa的单一成分,该成分对MT-2细胞增殖有抑制作用.经蛋白酶E和NaIO4处理分析,该成分的抗肿瘤作用与蛋白质成分有关,与糖成分无关,说明该成分是蛋白质.经二次元电泳法分离后确认该成分是单一蛋白质.结论:以上结果提示,五加皮抗肿瘤活性是一种分子量约64kDa的单纯蛋白质成分,该成分的进一步纯化将为抗肿瘤新药物的开发和中药有效成分的研究提供实验依据.     

阿魏菇抗肿瘤作用的研究进展

阿魏菇是一种有药用价值的名贵珍稀食用菌, 具有抗肿瘤的生物活性.本文从诱导肿瘤细胞凋亡、抑制肿瘤细胞增殖及核酸和蛋白质合成等方面对阿魏菇的抗肿瘤机制研究进展作一综述.     

棉酚抗肿瘤作用的研究进展

棉酚是一种多酚类化合物，具有抗肿瘤的生物学活性。文章从棉酚的化学结构、理化性质、抗肿瘤机制及抗肿瘤效果等方面作一综述。     

足叶乙(弋甘)(vp16-213)，治疗晚期肿瘤的观察(摘要)

足叶乙甙(VP16—213),是一种半合成的鬼臼酯素衍生物,抑制核苷转移,抑制DNA、RNA及蛋白质的合成,具有广谱的抗肿瘤活性。我院自1985年元月开始,在多种癌症患者身上使用VP16—213,使用剂量由小到大。     

Downregulation of Cdk1 and CyclinB1 Expression Contributes to Oridonin-induced Cell Cycle Arrest at G2/M Phase and Growth Inhibition in SGC-7901 Gastric Cancer Cells

Background: Oridonin isolated from Rabdosia rubescens, a plant used to treat cancer in Chinese folk medicine, is one of the most important antitumor active ingredients. Previous studies have shown that oridonin has antitumor activities in vivo and in vitro, but little is known about cell cycle effects of oridonin in gastric cancer. Materials and Methods: MTT assay was adopted to detect the proliferation inhibition of SGC-7901 cells, the cell cycle was assessed by flow cytometry and protein expression by Western blotting. Results: Oridonin couldinhibit SGC-7901 cell proliferation, the IC50 being 15.6 μM, and blocked SGC-7901 cell cycling in the G2/M phase. The agent also decreased the protein expression of cyclinB1 and CDK1. Conclusions: Oridonin may inhibit SGC-7901 growth and block the cells in the G2/M phase by decreasing Cdk1 and cyclinB1 proteins.     

华蟾素注射液及其活性成份抗肿瘤机制的研究进展

华蟾素注射液是临床应用较广的抗肿瘤中药制剂，具有抗肿瘤、增强机体免疫力等作用，但对其确切的有效成份仍需进一步研究。本文将近年国内外华蟾素注射液及其活性成份在抑制肿瘤细胞增殖、诱导肿瘤细胞分化、促进肿瘤细胞凋亡、提高机体免疫力等方面的实验研究进行综述，供临床应用参考。     

Histone H3 and heat shock protein GRP78 are selectively cross-linked to DNA by photoactivated gilvocarcin V in human fibroblasts

Gilvocarcin V (GV) is an antitumor antibiotic with a coumarin-based aromatic structure that promotes protein-DNA cross-linking when photoactivated by near-UV light. We have now identified several proteins that are selectively cross-linked to DNA in human fibroblasts by photoactivated GV, using NH2-terminal amino acid sequencing and Western blot analysis of the purified cross-linked proteins. The selectively cross-linked proteins are histone H3 and GRP78, a heat shock protein belonging to the heat shock protein-70 family. The hydrophobic leader sequence is missing from the cross-linked GRP78, suggesting that only the processed form of the protein is cross-linked to DNA. It is primarily the phosphorylated form of histone H3 that is cross-linked to DNA. Gel retardation analysis from four different GV-treated human fibroblast cell lines revealed two distinct shifted bands, and subsequent immunoblotting confirmed in situ that the slower and the faster bands, respectively, contained GRP78 and histone H3 cross-linked to DNA. The selective cross-linking of these particular proteins is dependent on UV irradiation in the presence of GV, which may help to clarify the unique molecular mechanism of this potent antitumor agent.     

Action of interferons in hairy cell leukemia

We have investigated the direct effects of interferon (IFN) on hairy cells (HCs) isolated from patients with hairy cell leukemia using one- and two-dimensional gel electrophoresis. We have previously characterized the induction of synthesis of 10-16 specific proteins by IFN-alpha 2b in HCs, as analyzed by one-dimensional electrophoresis. By two-dimensional electrophoresis, we have now confirmed this induction and shown that the synthesis of the same number of specific proteins is down-regulated in HCs exposed to IFN-alpha 2b. When compared to HCs, fewer proteins are induced by IFN-alpha 2b in other normal, or neoplastic, lymphoid cells. We also report that protein induction occurs in HCs exposed in vivo to IFN-alpha 2b. We have demonstrated the presence of tubuloreticular structures in the cytoplasm of HCs exposed to IFN-alpha 2b in vitro, using transmission electron microscopy. We now report that these too are seen in HCs exposed to IFN in vivo during therapy. We investigated the effects of IFN-gamma on HCs and found that it also induces specific proteins. The pattern of induced proteins is distinctly different after IFN-gamma exposure in vitro. The fact that such induction occurs suggests that HCs possess also a receptor for IFN-gamma. These results demonstrate that there are direct effects of IFN-alpha on HCs and that such direct effects might be important in the antitumor activity of IFN-alpha in hairy cell leukemia.     

A peptide fraction from germinated soybean protein down-regulates PTTG1 and TOP2A mRNA expression, inducing apoptosis in cervical cancer cells

The aim of this study was to evaluate the effect of a peptide fraction, obtained from a germinated soybean protein hydrolysate, on the viability, apoptosis and cancer related gene expression in HeLa cells. Soybean was germinated for 0-6 days and proteins were isolated from the seeds. Protein isolates, without ethanol-soluble phytochemicals, were hydrolyzed with digestive enzymes and their effect on growth in HeLa cells was evaluated. The most active hydrolysate was separated by ultrafiltration into five peptide fractions. A >10 kDa fraction was the most active against cancer cells. This fraction down-regulated PTTG1 and TOP2A mRNA expression (two genes considered as therapeutic targets) and induced apoptosis in cancer cells activating the caspase cascade and causing DNA fragmentation. Germinated soy protein isolates could be a bioactive ingredient of functional food.     

Bufalin exerts antitumor effects by inducing cell cycle arrest and triggering apoptosis in pancreatic cancer cells

As one of the most aggressive human malignancies, pancreatic cancer is a leading cause of cancer-related deaths worldwide and only about 4 % of patients will live 5 years after diagnosis. Eighty to approximately eighty-five percent of patients are diagnosed with an unresectable or metastatic disease, which is correlated with poor prognosis and low survival rate. Therefore, it is tremendously significant to exploit novel chemicals to prevent and treat pancreatic cancer. Previous research and clinical studies have demonstrated that many natural products derived from traditional Chinese medicine (TCM) such as camptothecin derivatives and vinca alkaloids could be effective antitumor compounds, hinting that TCM is a promising source for developing new antitumor drugs. In this report, we investigated the effects of bufalin, a primary active ingredient of the traditional Chinese medicine Chan-Su, on pancreatic cancer cell lines PANC-1 and CFPAC-1 and studied the underlying molecular mechanism. We found that exposure to bufalin could suppress the proliferation of pancreatic cancer cells time and dose dependently. We used flow cytometry to study the effects of bufalin on apoptosis and cell cycle distribution in PANC-1 and CFPAC-1 cells. The results indicated that bufalin could significantly induce both apoptosis and G2/M cell cycle arrest in pancreatic cancer cells. With western blotting, we found that the expression level of an antiapoptotic protein heat shock protein 27 (Hsp27) and its partner molecule p-Akt was decreased upon the treatment with bufalin. Besides, bufalin activated pro-caspase-3 and pro-caspase-9 and modulated the expression level of Bcl-2 and Bax. These data suggested that bufalin may trigger apoptosis by targeting Hsp27, which could inhibit apoptosis by interfering with key apoptotic proteins. The influence on the level of cylinB1, CDK1, and p21 was also observed after bufalin treatment, and the relationship between Hsp27 and the cell cycle-related proteins mentioned above deserves much more research. In addition, our data showed that bufalin could enhance the growth inhibition effect of gemcitabine in above pancreatic cancer cells. Taken together, bufalin might be worthy of further study for its potential as a therapeutic agent for pancreatic cancer treatment.     

Experimental pharmacology of auromomycin in L1210 tumor cells in vitro and in vivo

The antibiotic protein auromomycin (AUR) is composed of a chromophore and an apoprotein. The in vitro cytotoxic activity of AUR is associated with the chromophore, whereas the apoprotein is not cytotoxic. Exposure to AUR blocks cell cycle traverse in G2-M phase. Both AUR and the chromophore exhibit antitumor activity against murine L1210 leukemia, both in vitro and in vivo. Similarly, neocarzinostatin and its chromophore also show antitumor activity against L1210 tumor cells in vitro and in vivo. AUR and neocarzinostatin apoproteins have no antitumor activity. The pharmacokinetics of 125I-labeled AUR in L1210 tumor-bearing mice shows a triexponential drug decay and initial rapid clearance of drug from the blood. The distribution of AUR-associated radioactivity into various tissues is rapid, and at the end of 24 hr, there is little drug accumulation in the tissues. During the first hr, greater than 50% of the administered drug is eliminated in the urine. As the chromophores alone possess antitumor activity, the effect of these antitumor proteins in cancer chemotherapy might be significantly increased by the administration of protein preparations containing biologically active and stable chromophores.     

Antitumor agent, physalin F from Physalis angulata L.

Physalin F and physalin D were isolated and characterized from the ethanolic extract of the whole plant of Physalis angulata L. (Solanaceae). Systematic fractionation of the ethanolic extract of the plant led to characterization of physalin F from the fraction PAIV-2 as an active ingredient which showed cytotoxicity in vitro by DEA and MTT assays on 8 cancer cell lines, five human cancer cell lines: HA22T(hepatoma), HeLa(cervix uteri), KB(nasopharynx), Colo-205(colon) and Calu-1(lung); and three animal cancer cell lines: H1477(melanoma), Hep-2(laryngeal) and 8401(glioma). It was found that the anti-hepatoma action is the strongest, and the anti-HeLa is the next. Physalin F also had an antitumor effect in vivo against P388 lymphocytic leukemia in mice whereas physalin D was inactive both in vitro and in vivo.     

Effect of low-intensity laser radiation on the functional potential of neutrophilic granulocytes in blood of tumor-bearing animals

Peripheral blood was sampled for cytochemical assay of cationic proteins from three groups of animals--intact ones, those with tumor C45 and bearers of the same tumor treated with helium-laser radiation and chemotherapy. Radiotherapy involved such manifestations of enhanced nonspecific antitumor resistance and, in particular, mobilization of the cellular component, as increased number of neutrophils containing cationic protein granules and relatively high levels of such proteins in them. Cytochemical assay of cationic proteins in neutrophil granules may serve as a criterion of nonspecific antitumor resistance assessment.     

Characterization of a duocarmycin-DNA adduct-recognizing protein in cancer cells.

Duocarmycins have been reported to derive their potent antitumor activity through a sequence-selective minor groove alkylation of N3 adenine in double-stranded DNA. We have used gel mobility shift assays to detect proteins that bind to DNA treated in vitro with duocarmycin SA and identified a protein, named duocarmycin-DNA adduct recognizing protein (DARP), which binds with increased affinity to duocarmycin-damaged DNA. Examination with partially purified DARP revealed that the protein recognized not only the DNA adduct of structurally related drug, CC-1065, but unexpectedly, the protein also recognized the DNA adduct of another chemotype of minor groove binder, anthramycin. These results demonstrate that DARP recognizes the structural alteration of DNA induced by these potent DNA-alkylating drugs, suggesting the possibility that the protein might modulate the antitumor activity of these drugs.