Synovial stimulatory protein fragments copurify with woodchuck hepatitis virus: implications for the etiology of arthritis in chronic hepatitis B virus infection.
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Amino Acid Sequence↗
Biomedical subjects
T Block
Publications and source records attributed to T Block.
Limited proteolysis induces woodchuck hepatitis virus infectivity for human HepG2 cells.
Previous work from our laboratory has shown that digestion of hepatitis B virus (HBV) with V8 protease rendered the virus infectious for human hepatoblastoma cell line (HepG2). It was hypothesized that the cleavage exposes a 16 amino acid region that includes a consensus 'fusion' motif necessary to mediate infectivity. Since woodchuck hepatitis virus (WHV) and HBV possess significant homology in this region of their envelope proteins, including the V8 protease cleavage site, the possibility that WHV infectivity for HepG2 cells could be induced by V8 digestion was explored. WHV isolated from the serum of chronically infected woodchucks, digested with V8 protease, was shown to loose its preS domain. V8 digested WHV eluted from gel filtration columns with a size similar to that of undigested virus, suggesting that digestion with V8 protease did not cause significant changes in virion size. The amount of progeny virus secreted into the culture medium following infection of HepG2 cells with V8 digested WHV reached 2.5 pg/ml, after 8 days. Moreover, WHV DNA replicative intermediates could be detected in the cells following infection with protease digested, but not undigested, viruses. These data suggest that protease modification of WHV, a non-human virus, induced infectivity for human tissue culture cells. These results are consistent with the hypothesis that exposure of an amino acid region of the envelope polypeptide that contains a consensus fusion motif is important in Hepadnavirus entry.
Amino Acid Sequence↗
A proteomic approach for the discovery of early detection markers of hepatocellular carcinoma.
Individuals chronically infected with hepatitis B or C virus (HBV, HCV) are at high risk for the development of hepatocellular carcinoma (HCC), with disease progression occurring relentlessly over many years. The diagnosis of HCC usually occurs at late stages in the disease when there are few effective treatment options and the prognosis for patients with HCC is very poor. The long latency period, together with clearly identified at risk populations, provide opportunities for earlier detection that will allow more timely and effective treatment of this devastating cancer. We are using a proteomic approach to test the hypothesis that changes in the amount of certain serum polypeptides, or changes in their post-translational modifications, can be used to predict the onset of HCC. Advances in the standardization of two dimensional gel electrophoresis (2DE) coupled with computerized image analysis now permit the reproducible resolution of thousands of polypeptides per run. Serum polypeptides from individuals at different stages in the disease continuum are being resolved by 2DE to identify those that change with disease progression. Polypeptides found by this method can be further characterized by mass spectrometry. In addition, the potential for changes in the glycan structure of certain polypeptides to serve as a marker for disease progression can be explored. The proteomic approach is expected to liberate us from the need to "cherry pick" or guess the best biomarkers and let the data tell us which are the best indicators of disease. Information may also be gleaned about the pathobiology of the disease process.
Biomarkers↗
Fluorine-18-fluorodeoxyglucose positron emission tomography is useless for the detection of local recurrence after radical prostatectomy.
OBJECTIVE: After radical retropubic prostatectomy a rise of the prostate-specific antigen (PSA) indicates a local recurrent or metastatic disease. If the bone scan shows no apparent bone metastasis, morphological imaging methods like x-ray computed tomography, magnetic resonance imaging or transrectal ultrasound often cannot distinguish between postoperative scar and local recurrence. Therefore we investigated the feasibility of fluorine-18-fluorodeoxyglucose positron emission tomography (F-18 FDG PET) for metabolic characterization of prostatic cancer, especially for differentiation of scar or recurrent prostate cancer after radical prostatectomy. METHODS: Dynamic PET with 370 MBq F-18 deoxyglucose (F-18 FDG) up to 60 min p.i. was performed in 2 patients with biopsy-proven benign prostatic hyperplasia, in 11 patients with a histologically proven prostate cancer prior to radical retropubic prostatectomy (RRP) and 7 patients with suspected local recurrence (with negative bone scan) after RRP prior to biopsy of anastomosis (3 local recurrence, 4 postoperative scar). RESULTS: Prostate cancer showed a very low F-18 FDG uptake. The placement of regions of interest was only possible by the use of other imaging methods. There was not difference between the F-18 FDG uptake of benign prostate hyperplasia, prostate carcinoma, postoperative scar or local recurrence after radical prostatectomy. CONCLUSION: F-18 FDG seems not to be useful to distinguish between postoperative scar and local recurrence after radical prostatectomy.
Adenocarcinoma↗
Preclinical activity of trans-indazolium[tetrachlorobisindazoleruthenate(III)] (NSC 666158; IndCR; KP 1019) against tumour colony-forming units and haematopoietic progenitor cells.
Trans-indazolium[tetrachlorobisindazoleruthenate(III)] (KP 1019) is a new heavy metal complex with promising activity against tumour cell lines and in animal models. We studied the antineoplastic effects of KP 1019 (final concentrations: 1, 10, 100 micrograms/ml) on in vitro proliferation of clonogenic cells from freshly explanted human tumours in a capillary soft agar cloning system, and compared the activity of KP 1019 with conventional antineoplastic agents. 53 of 75 specimens (71%) showed adequate growth in controls. KP 1019 inhibited tumour colony formation in a concentration-dependent manner in both short- (1 h) and long-term (21 d) exposure experiments. KP 1019 at 100 micrograms/ml with 1 h exposure was as active as bleomycin, cisplatin, doxorubicin, etoposide, 5-fluorouracil, methotrexate, mitomycin-C and vinblastine, with only paclitaxel more active than KP 1019 (P = 0.002). The antitumour activity of KP 1019 was more pronounced after long-term exposure, indicating the potential schedule dependency of KP 1019. Activity was observed against non-small cell lung, breast and renal cancer. We conclude that if appropriate plasma levels can be achieved in patients, KP 1019 may have significant clinical activity against a variety of different tumour types.
Cell Division↗
Efficacy of 5'-nor-anhydrovinblastine (vinorelbine), against freshly explanted clonogenic human tumor cells in vitro.
Vinorelbine (5'-nor-anhydrovinblastine) is a semisynthetic vinca alkaloid currently undergoing extensive clinical evaluation. We have studied the antitumor effect of vinorelbine (final concentrations: 8.4-1000.0 ng/ml) against freshly explanted clonogenic cells from 102 human tumors using a capillary soft agar cloning system and have compared the compound's activity with vinblastine, vincristine, vindesine, paclitaxel, docetaxel, and other clinically used anticancer agents. Four specimens were excluded from further analyses (3 bacterial or fungal contamination, 1 benign histology). Fifty-one of the remaining 98 (52%) specimens had adequate colony formation in control capillaries. Vinorelbine showed concentration-dependent antitumor activity against a variety of solid tumors. At clinically relevant concentrations (0.1 x peak plasma concentrations in humans) vinorelbine inhibited 21 of 49 specimens (43%) and was as active as vinblastine, vincristine, vindesine, bleomycin, doxorubicin, 5-fluorouracil, mitomycin-C, cisplatin, methotrexate, and etoposide. However, paclitaxel (71% inhibition, p = 0.006) and docetaxel (78% inhibition, p = 0.002) were significantly more active than vinorelbine. Moreover, vinorelbine showed antitumor activity against several tumor types and in particular against breast cancer but also in non-small cell lung cancer. We conclude that vinorelbine has a wide spectrum of in vitro activity against freshly explanted human tumors and that the clinical activity of this compound against breast cancer and non-small cell lung cancer is reflected in vitro.
Antineoplastic Agents, Phytogenic↗
[Percutaneous cystoscopy in dogs and cats].
Cystoscopy enables a reliable diagnosis of urinary bladder diseases. The use of transurethral or perineal endoscopic technique is limited by anatomical features. Therefore it was examined, if the prepubic percutaneous access shows advantages referring to diagnosis and treatment. Using this technique three dogs and two cats were examined. The endoscopic instrumentarium and the technical procedure are described.
Animals↗
Evidence that N-linked glycosylation is necessary for hepatitis B virus secretion.
Human hepatitis B virus (HBV) envelopes contain three distinct glycoproteins called L, M, and S HBsAg. Each is posttranslationally modified to contain N-linked oligosaccharides. N-linked oligosaccharides, after attachment to a polypeptide backbone, are processed by enzymes within the endoplasmic reticulum (ER). There is uncertainty about what role, if any, these N glycans and their modification in the ER play in the function of the HBV envelope proteins. By treating hepatoblastoma cultures which secrete HBV (HepG 2.2.15 cells) with inhibitors of different steps of the glycosylation and glycan modifying pathway, we provide evidence that glycosylation and the first step in the processing pathway are necessary for virion, but not subviral particle, secretion. That is, using a highly sensitive immunoprecipitation/polymerase chain reaction system, enveloped HBV could not be detected in the medium of HepG2.2.15 cells incubated with tunicamycin. However, HBV subviral particle secretion was not prevented by tunicamycin. Moreover, inhibitors of alpha-glucosidase I (the first step in the glycan processing pathway) also prevented virion secretion. Inhibitors of mannose trimming (a later step) and glycolipid synthesis, did not prevent virion secretion, defining the limits of the glycosylation requirements in secretion. These results demonstrate a requirement for N-glycosylation and glucosidase processing in the secretion of virions and further distinguish between the requirements for virion and subviral particle secretion.
1-Deoxynojirimycin↗
Vertical transport in GaAs/AlxGa1-xAs superlattices by a microwave time-of-flight technique.
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Journal Article↗
Investigation of the comparative effects of 2-chlorodeoxyadenosine on tumor colony forming units in vitro.
2-CdA is a deaminase-resistant purine analogue which has shown clinical activity against various hematological tumors, and is currently undergoing clinical phase II trials. The objectives of our study were to determine the activity of 2-CdA against freshly explanted clonogenic cells from non-hematological human tumors and compare this agent with other clinically useful anticancer agents. We also compared short-term (1 hour) and long-term (21-28 days) exposures. For short-term exposure (1-hour), final concentrations were 0.57, 5.7, 57, and 114 ng/ml. Inhibition of tumor specimens was concentration-dependent: 0.57 ng/ml: 1/51 (2%), 5.7 ng/ml: 4/52 (7%), 57 ng/ml: 11/52 (21%), 114 ng/ml: 27/50 (54%). At concentrations > or = 57 ng/ml, 2-CdA was as active as cisplatin, doxorubicin, 5-fluorouracil, mitomycin-C, vinblastine, and etoposide. For long-term exposures (21-28 days), final concentration of 2-CdA were 0.57, 5.7, and 57 ng/ml. At 0.57 ng/ml, 2-CdA was active in 4/54 (7%) specimens [5.7 ng/ml: 13/54 (24%), 57 ng/ml: 40/54 (74%)]. A head-to-head comparison with short-term exposures demonstrated greater activity if the drug exposure time was extended. Using the strategy for testing other standard agents (in vitro dose of 1/10th achievable peak plasma concentration), one would predict clinical response rates for single agent bolus or short-term administration of 2-CdA to be in the neighborhood of 7%. Longer durations of infusion or multiple doses might increase the response rate to about 24%. If higher peak plasma concentration could be achieved, dose-dependent increases in clinical responses might be achievable. We conclude that 2-CdA is active against clonogenic cells from freshly explanted non-hematological human tumor specimens at high concentrations.
Antineoplastic Agents↗
An HSV-1 containing the rat beta-glucuronidase cDNA inserted within the LAT gene is less efficient than the parental strain at establishing a transcriptionally active state during latency in neurons.
The herpes simplex virus vector 17/LAT-RGUSB has previously been shown to express beta-glucuronidase enzyme activity stably in the trigeminal ganglia and brain stems of beta-glucuronidase-deficient mutant mice. However, the number of beta-glucuronidase expressing cells in trigeminal ganglia latently infected with 17/LAT-RGUSB was smaller than expected. Using normal mice for further characterization of 17/LAT-RGUSB latent infection, no appreciable differences were found between the vector and wild-type virus in: (1) their abilities to replicate in acutely infected ganglia; (2) their abilities to reactivate from latently infected ganglia: or (3) the quantities of viral DNA in tissues during the acute or the latent phases of infection. Using a minor LAT (mLAT)-specific probe to detect transcription by in situ hybridization, it was found that the intensity of the signal from individual cells latently-infected with 17/LAT-RGUSB or wild-type virus was similar. However, the vector-infected ganglia had only 20% as many positive cells as in wild-type infection. These data suggest that 17/LAT-RGUSB virus established latency similarly to wild-type virus, but that the LAT-promoter driven gene expression was compromised.
Animals↗
Long term herpes simplex virus type 1 infection of nerve growth factor-treated PC12 cells.
The behaviour of herpes simplex virus type 1 (HSV-1) strain 17 in tissue cultures of PC12 cells treated with nerve growth factor (NGF) was studied. PC12 cells respond to NGF by ceasing to proliferate and extending long neurites. After differentiation with NGF, cultures were infected with HSV-1 and maintained in the presence of the hormone for several weeks. These long-term infected cultures were tested for HSV DNA, transcripts and the ability to produce virus, before and after NGF removal. Before NGF removal, the cultures were characterized by little or no virus production and the presence of HSV-1 DNA in a predominantly endless form. In situ analysis of long-term infected cultures revealed latency-associated transcript expression in only a portion of the cells. However, as shown by an infectious centre assay, virus was present in almost all cells in the population. Moreover, removal of NGF from long-term cultures resulted in the appearance of significantly increased amounts of virus in the media. The degree to which this system resembles HSV latency in vivo is discussed.
Animals↗
In-vitro cell growth of human urothelial tumor cell lines under exposure with IL-3, GM-CSF, G-CSF and by combined administration with methotrexate, vinblastine, adriamycin and cisplatin.
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Antineoplastic Combined Chemotherapy Protocols↗
[Chemotherapy of bladder carcinoma. Current status and trends].
Cisplatin and methotrexate are the most effective single agents used in the chemotherapy of metastatic transitional cell carcinoma. These agents should be included in polychemotherapy regimens. Polychemotherapy, especially with MVAC, leads to improved rates of complete remission. The attainment of complete remission has a statistically significant association with duration of survival. However, after 5 years there is no further survival advantage. If one quarter of patients achieve a CR, with a duration of more than 3 years in only half of them, a durable response can be expected in only 13% of treated patients. That means a maximal therapeutic benefit of 10-15% in polychemotherapy of bladder cancer, which is associated with relatively high toxicity. Prospective randomized trials are needed to determine the efficacy of treatment with two versus four agents. Dose intensification of the agents in the MVAC regimen has not resulted in significant improved remission rates. This approach is also limited by the appearance of non-haematotoxic side effects.
Antineoplastic Agents↗
Detection of somatic changes in human renal cell carcinomas with oligonucleotide probes specific for simple repeat motifs.
The purpose of our study was to detect somatic changes in renal cell carcinoma by multilocus fingerprinting. DNA fingerprints were generated from the DNA of normal and malignant renal tissue samples of 29 patients with nonhereditary kidney carcinoma by using oligonucleotide probes specific for simple repeat motifs such as (GTG)5, (CA)8, (GACA)4, or (TTAGGG)3. Each probe rendered a typical fingerprint pattern, because it is specific with respect to the target regions recognized in the genome. The restriction enzymes used were HinfI and HaeIII. Changed banding patterns were detected by using (GTG)5 in 20% of the tumors, in 20% for (CA)8 after HinfI digestion, and in 10% after HaeIII digestion. Even more informative probes were (GACA)4, showing 70% changes after HaeIII digestion, and (TTAGGG)3, with 80% changes after digestion with either enzyme. Since the simple repeat motifs recognized by (GACA)4 are localized on the short arms of the acrocentric chromosomes (13, 14, 15, 21, and 22), it is possible that sequences important for renal carcinogenesis are present in these regions. The observation of changes in regions to which (TTAGGG)3 hybridizes points to an involvement of DNA elements in telomeric sequence related regions in human kidney tumor formation.
Adult↗
Inhibitory effects on in vitro cell growth of human urothelial tumor cell lines under the combined administration of hematopoietic growth factors and clinically relevant antineoplastic agents.
In five of eight human transitional carcinoma cell (TCC) lines a proliferative response has been reported during exposure to interleukin-3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF) and granulocyte colony stimulating factor (G-CSF). To elucidate possible growth-modulating effects of these factors combined with clinically relevant antineoplastic agents, cells of the human TCC lines EJ28 and T24 were exposed to methotrexate (MTX), vinblastine (VBL), doxorubicin (DXR) and cisplating (CDDP) with and without single or continuous exposure to IL-3, GM-CSF and G-CSF at concentrations of 1-100 ng/ml. Compared with cells exposed only to chemotherapy, significant inhibitory effects occurred as a result of continuous exposure to IL-3 or GM-CSF at the highest activities with CDDP and MTX in the T24 and EJ28 lines; continuous G-CSF administration (100 ng/ml) in combination with MTX led to significant growth inhibition in the EJ28 line. In contrast, no significant growth modulation was found on combined administration of DXR or VBL with any one of the three colony stimulating factors tested.
Antineoplastic Agents↗
Preclinical activity of taxotere (RP 56976, NSC 628503) against freshly explanted clonogenic human tumour cells: comparison with taxol and conventional antineoplastic agents.
Taxotere (TER) and taxol (TA) are new antitumour agents currently undergoing clinical evaluation. We studied the antineoplastic effects of these agents (final concentrations: 4.0, 0.4, 0.04 mumol/l) on the in vitro proliferation of clonogenic cells from freshly explanted human tumours using a capillary soft agar cloning system. We also compared the activity of these new compounds to conventional antineoplastic agents (bleomycin, cisplatin, dacarbazine, doxorubicin, etoposide, 5-fluorouracil, vinblastine, interferon-alpha 2). Using a 21-28-day continuous drug exposure, 54/81 specimens (67%) were evaluable for comparisons, and using a 1-h drug exposure followed by 21-28 days incubation, 50/80 specimens (63%) were similarly evaluable. With both schedules, TA and TER showed concentration-related antitumour activity. At 0.4 mumol/l, median colony survival was 0.61 x control (range 0.09-0.96) for TA and 0.51 x control (0.15-0.81) for TER in the 1-h incubation (P = 0.0002). Median colony formation was also reduced significantly more by TER as compared to TA in the long-term incubation schedule. Statistical analysis indicated that TER but not TA was significantly more active than cisplatin (P = 0.02), doxorubicin (P = 0.01), 5-fluorouracil (P = 0.01) and interferon-alpha 2 (P = 0.01). We conclude that TER and TA are more active against in vitro tumour colony formation from freshly explanted human tumours. TER appears to be slightly more active than taxol and promises to be active against tumours resistant to conventional antineoplastics.
Antineoplastic Agents↗
[Organ-preserving therapy of muscle-invasive bladder carcinoma].
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Antineoplastic Agents↗