Antitumor activity of syngeneic/autologous graft-versus-host disease.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
R J Jones
Publications and source records attributed to R J Jones.
Pharmacology of bone marrow transplantation conditioning regimens.
Explore the source record for details and available documents.
Bone Marrow Transplantation↗
BCR-ABL-mediated inhibition of apoptosis with delay of G2/M transition after DNA damage: a mechanism of resistance to multiple anticancer agents.
A critical determinant of the efficacy of antineoplastic therapy is the response of malignant cells to DNA damage induced by anticancer agents. The p53 tumor-suppressor gene is a critical component of two distinct cellular responses to DNA damage, the induction of a reversible arrest at the G1/S cell cycle checkpoint, and the activation of apoptosis, a genetic program of autonomous cell death. Expression of the BCR-ABL chimeric gene produced by a balanced translocation in chronic myeloid leukemia, confers resistance to multiple genotoxic anticancer agents. BCR-ABL expression inhibits the apoptotic response to DNA damage without altering either the p53-dependent WAF1/CIP1-mediated G1 arrest or DNA repair. BCR-ABL-mediated inhibition of DNA damage-induced apoptosis is associated with a prolongation of cell cycle arrest at the G2/M restriction point; the delay of G2/M transition may allow time to repair and complete DNA replication and chromosomal segregation, thereby preventing a mitotic catastrophe. The inherent resistance of human cancers to genotoxic agents may result not only by the loss or inactivation of the wild-type p53 gene, but also by genetic alterations such as BCR-ABL that can delay G2/M transition after DNA damage.
Antineoplastic Agents↗
Dynamics of maize endosperm development and DNA endoreduplication.
Endosperm development in Zea mays is characterized by a period of intense mitotic activity followed by a period in which mitosis is essentially eliminated and the cell cycle becomes one of alternating S and G phases, leading to endoreduplication of the nuclear DNA. The endosperm represents a significant contribution to the grain yield of maize; thus, methods that facilitate the study of cellular kinetics may be useful in discerning cellular and molecular components of grain yield. Two mathematical models have been developed to describe the kinetics of endosperm growth. The first describes the kinetics of mitosis during endosperm development; the second describes the kinetics of DNA endoreduplication during endosperm development. The mitotic model is a modification of standard growth curves. The endoreduplication model is composed of six differential equations that represent the progression of nuclei from one DNA content to another during the endoreduplication process. Total nuclei number per endosperm and the number of 3C, 6C, 12C, 24C, 48C, and 96C nuclei per endosperm (C is the haploid DNA content per nucleus) for inbred W64A from 8 to 18 days after pollination were determined by flow cytometry. The results indicate that the change in number of nuclei expressed as a function of the number of days after pollination is the same from one yearly crop to another. These data were used in the model to determine the endosperm growth rate, the maximum nuclei number per endosperm, and transition rates from one C value to the next higher C value. The kinetics of endosperm development are reasonably well represented by the models. Thus, the models provide a means to quantify the complex pattern of endosperm development.
Cell Nucleus↗
Analysis of the V beta T-cell receptor repertoire in autologous graft-versus-host disease.
Explore the source record for details and available documents.
Bone Marrow Transplantation↗
Assessment of aldehyde dehydrogenase in viable cells.
Cytosolic aldehyde dehydrogenase (ALDH), an enzyme responsible for oxidizing intracellular aldehydes, has an important role in ethanol, vitamin A, and cyclophosphamide metabolism. High expression of this enzyme in primitive stem cells from multiple tissues, including bone marrow and intestine, appears to be an important mechanism by which these cells are resistant to cyclophosphamide. However, although hematopoietic stem cells (HSC) express high levels of cytosolic ALDH, isolating viable HSC by their ALDH expression has not been possible because ALDH is an intracellular protein. We found that a fluorescent aldehyde, dansyl aminoacetaldehyde (DAAA), could be used in flow cytometry experiments to isolate viable mouse and human cells based on their ALDH content. The level of dansyl fluorescence exhibited by cells after incubation with DAAA paralleled cytosolic ALDH levels determined by Western blotting and the sensitivity of the cells to cyclophosphamide. Moreover, DAAA appeared to be a more sensitive means of assessing cytosolic ALDH levels than Western blotting. Bone marrow progenitors treated with DAAA proliferated normally. Furthermore, marrow cells expressing high levels of dansyl fluorescence after incubation with DAAA were enriched for hematopoietic progenitors. The ability to isolate viable cells that express high levels of cytosolic ALDH could be an important component of methodology for identifying and purifying HSC and for studying cyclophosphamide-resistant tumor cell populations.
Aldehyde Dehydrogenase↗
Inhibition of apoptosis during development of colorectal cancer.
Colorectal tumorigenesis proceeds through an accumulation of specific genetic alterations. Studies of the mechanism by which these genetic changes effect malignant transformation have focused on the deregulation of cell proliferation. However, colorectal epithelial homeostasis is dependent not only on the rate of cell production but also on apoptosis, a genetically programmed process of autonomous cell death. We investigated whether colorectal tumorigenesis involved an altered susceptibility to apoptosis by examining colorectal epithelium from normal mucosa, adenomas from familial adenomatous polyposis, sporadic adenomas, and carcinomas. The transformation of colorectal epithelium to carcinomas was associated with a progressive inhibition of apoptosis. The inhibition of apoptosis in colorectal cancers may contribute to tumor growth, promote neoplastic progression, and confer resistance to cytotoxic anticancer agents.
Adenomatous Polyposis Coli↗
Cytotoxic T cells overcome BCR-ABL-mediated resistance to apoptosis.
Chronic myeloid leukemia is a disease marked by expanded clonal hematopoiesis; it is incurable by chemotherapy or radiation but is cured in a majority of patients receiving bone marrow transplantation from nonidentical sibling donors, an outcome generally attributed to a T cell-mediated graft-versus-leukemia effect. In this report, we examine the effect of the P210BCR-ABL fusion protein of the BCR-ABL oncogene, the molecular hallmark of chronic myelogenous leukemia, on the sensitivity of mouse cell lines to apoptosis induced by chemotherapy, radiation, or activated cytotoxic T lymphocytes (CTLs). We find that, although cells expressing P210BCR-ABL by gene transfer are more resistant than their normal counterparts to apoptosis induced by chemotherapy or radiation, they are equally susceptible to apoptosis induced by alloreactive CTLs. These results show that CTLs overcome BCR-ABL-mediated resistance to apoptosis and, therefore, provide a biological correlation for the success of allogeneic bone marrow transplantation in chronic myelogenous leukemia.
Animals↗
Minireview: nucleotide prodrugs.
Nucleotides have shown interesting biological activities in a wide variety of antiviral, antiproliferative, immunomodulatory and other biological assays, and they present promising drug candidates. Because of their negative charge(s) nucleotides suffer from some disadvantages which can be successfully overcome by the utilization of nucleotide prodrugs. Nucleotide prodrugs were successfully used to increase oral absorption of nucleotides in vivo. By taking advantage of intracellular triggers (reducing potential, enzyme activity, pH), nucleotide prodrugs can be used in vitro for the intracellular delivery of the nucleotide resulting in enhanced potency and in some cases enhanced selectivity. Nucleotide prodrugs have also been utilized for tissue specific delivery of the nucleotides in vivo resulting in altered selectivity and reduced toxicity. For nucleotide prodrugs, their ultimate intended use is (in most cases) in vivo for the treatment of a disease. Thus, it is important to incorporate adequate assays and design criteria into any prodrug effort. In vivo systems are complicated because of metabolism, excretion and tissue distribution of the prodrug and the parent. Thus, results of in vitro assays have to be interpreted cautiously because they may be unsuitable predictors of the in vivo situation.
Molecular Structure↗
Probable propafenone-induced transient global amnesia.
OBJECTIVE: To describe a probable case of transient global amnesia caused by propafenone. This adverse effect has not been previously described for this agent. CASE SUMMARY: A 61-year old man with a history of sick sinus syndrome with persistent atrial fibrillation and infrequent premature ventricular contractions was admitted to the hospital for symptoms of amnesia and disorientation to time, place, and date. He began taking propafenone only 6 days prior to admission because of uncontrolled atrial fibrillation and symptoms of fatigue. His atrial fibrillation subsequently had converted to normal sinus rhythm while he received propafenone without adverse effects prior to this episode. His symptoms of amnesia resolved approximately 6-7 hours after discontinuing the propafenone therapy. DISCUSSION: Propafenone is a class 1C antiarrhythmic agent that blocks fast sodium channels in heart muscle and Purkinje fibers similar to the action of encainide and flecainide. It also produces weak beta- and calcium-channel blockade. It has a significant adverse effect profile, with 30-45% of patients reporting cardiac adverse effects and 15-20% experiencing noncardiac events. Central nervous system effects that parallel amnesia have been reported in 10-15% of the patients, including dizziness, ataxia, drowsiness, fatigue, confusion, and paranoia. Propafenone's distribution, clearance, and structural similarity to propranolol contribute to its central nervous system effects. CONCLUSIONS: The rapid resolution of this patient's symptoms after discontinuing propafenone therapy and the absence of recurrence lend credence to the probability of this effect. Comparable adverse effects, such as disorientation and temporary amnesia, have been reported in patients in the analogous agent, propranolol. Consequently, this is a likely, although rare, possible adverse effect with propafenone for which patients should be monitored.
Amnesia↗
Association of BK virus with failure of prophylaxis against hemorrhagic cystitis following bone marrow transplantation.
PURPOSE: Hemorrhagic cystitis (HC) after bone marrow transplantation (BMT) has been ascribed to cyclophosphamide metabolites. HC has also been associated with excretion of the BK type of polyomavirus. The relative contributions of cyclophosphamide metabolites and BK virus in the development of HC following BMT are unknown. PATIENTS AND METHODS: We conducted a randomized trial to compare mesna with forced diuresis for prophylaxis against HC in 147 BMT recipients. We studied the association of BK virus with HC in 95 consecutive BMT recipients by prospectively monitoring urinary excretion of BK virus using polymerase chain reaction amplification of viral gene sequences. RESULTS: HC occurred in 37 of 147 (25.2%) transplant recipients. The incidence of HC was similar in patients given mesna (26.8%, 19 of 71) or forced diuresis (23.7%, 18 of 76), and in recipients of allogeneic (27.2%, 18 of 64) or autologous marrow (22.9%, 19 of 83). The incidence of HC was unrelated to primary disease, preparative regimen, or occurrence of graft-versus-host disease (GVHD). Excretion of BK virus was demonstrated in 50 of 95 patients (52.6%); 38 patients (40%) had persistent BK viruria (> or = two consecutive positive samples). HC occurred in 19 of 38 patients (50%) with persistent BK viruria, in one of 12 (8.3%) with only a single urine sample positive for BK virus, and in none of 45 who did not excrete BK virus (P < .0001). Shedding of BK virus also had a strong temporal correlation with onset of HC (r = .95). CONCLUSION: Mesna and forced diuresis are equally effective in abrogating the urothelial toxicity of preparative regimens for BMT. Since HC after BMT is virtually always associated with persistent BK viruria, strategies aimed at the prevention or elimination of viruria in BK seropositive recipients are warranted.
Adult↗
Impact of in vivo administration of interleukin 3 on proliferation, differentiation, and chemosensitivity of acute myeloid leukemia.
Early clinical trials of growth factor augmentation of induction chemotherapy for acute myeloid leukemia have yielded variable results. To test the hypothesis that this heterogeneity is a consequence of the pleiotropic effects of growth factors on leukemic cell biology, we measured the effects of in vivo interleukin 3 (IL-3) administration on leukemic cell proliferation and drug sensitivity. Thirty-four patients with acute myeloid leukemia with high-risk features or advanced myelodysplasia received IL-3 as a continuous infusion beginning 3 days prior to chemotherapy and continuing for the duration of intensive induction therapy. Bone marrow cells were studied prior to and after 3 days of IL-3 administration to assess changes in overall and leukemic progenitor cell [leukemia colony-forming unit (CFU-L)] proliferation, and progenitor cell sensitivity to 1-betad-arabinofuranosylcytosine. The median fold increase in overall leukemic cell proliferation in response to IL-3, assessed as expression of the nuclear antigen Ki67 in 28 patients, was 1.2. The median fold increase in percentage of cells in S phase (assessed in 29 patients) was 1.3. Despite the increase in overall cell proliferation in 70% of cases, CFU-L number increased in only 4 of 20 patients successfully studied (median day 4:day 1 ratio of CFU-L number, 0.6). While this suggests possible terminal differentiation of leukemic progenitor cells, expression of CD34, HLA-DR, c-kit, CD15, and CD14 were not consistently affected by the cytokine. 1-betad-Arabinofuranosylcytosine sensitivity of CFU-L increased significantly in 30% of cases, decreased in 30%, and was unchanged in 40%. Changes in overall cell proliferation (Ki67 expression) and CFU-L were independent predictors of change in 1-beta-d-arabinofuranosylcytosine sensitivity; increase in percentage of cells in S phase in response to IL-3 was correlated with attainment of complete remission. While these findings support the concept of cell cycle recruitment, IL-3 has marked pleiotropic effects on proliferation, differentiation, and survival of leukemic progenitors which make the clinical impact of in vivo cytokine administration for individual patients difficult to predict.
Acute Disease↗
Growth factor-mediated terminal differentiation of chronic myeloid leukemia.
Expression of the BCR-ABL chimeric gene in chronic myeloid leukemia results in the inhibition of apoptosis, a genetically programmed process of autonomous cell death. BCR-ABL and other genetic factors that suppress apoptosis confer cross-resistance to cytotoxic agents with diverse mechanisms of action. Eradication of the chronic myeloid leukemia clone requires strategies that circumvent this inherent resistance to cytotoxic therapy. We have determined that BCR-ABL expression augments the sensitivity of hematopoietic cells to growth factor-mediated signals of differentiation; hematopoietic growth factors induce the selective terminal differentiation of chronic myeloid leukemia progenitors at concentrations that allow optimal growth of normal progenitors. Hematopoietic growth factors may be an effective strategy for the elimination of cytotoxic therapy-resistant leukemic cells by inducing their terminal differentiation while allowing concomitant expansion of coexistent normal hematopoietic progenitors.
Animals↗
Development of antisense therapeutics. Implications for cancer gene therapy.
Explore the source record for details and available documents.
Animals↗
Inhibition of apoptosis by BCR-ABL in chronic myeloid leukemia.
BCR-ABL expression is presumed to effect clonal expansion in chronic myeloid leukemia (CML) by deregulation of cell proliferation. However, most studies have found that relative rates of cell proliferation are not increased in CML. Moreover, we found that CML progenitors display a normal proliferative response to growth factors and do not manifest greater proliferative potential than normal progenitors. Growth of malignancies depends on an imbalance between the rate of cell production and the rate of cell death. We found that BCR-ABL expression inappropriately prolongs the growth factor-independent survival of CML myeloid progenitors and granulocytes by inhibiting apoptosis, a genetically programmed process of active cell death; inhibition of BCR-ABL expression by antisense oligonucleotides reversed the suppression of apoptosis as well as the enhancement of survival. The decreased rate of programmed cell death appears to be the primary mechanism by which BCR-ABL effects expansion of the leukemic clone in CML.
Animals↗
Topoisomerase II levels and drug sensitivity in adult acute myelogenous leukemia.
The topoisomerase (topo) II-directed agents etoposide, daunorubicin (DNR), and amsacrine (m-AMSA) are widely used in the treatment of acute myelogenous leukemia (AML). In the present study, multiple aspects of topo II-mediated drug action were examined in marrows from adult AML patients. Colony-forming assays revealed that the dose of etoposide, DNR, or m-AMSA required to diminish leukemic colony formation by 90% (LD90) varied over a greater than 20-fold range between different pretreatment marrows. Measurement of nuclear DNR accumulation in the absence and presence of quinidine revealed evidence of P-glycoprotein (Pgp) function in 8 of 82 samples at diagnosis and 5 of 36 samples at first relapse, but the largest quinidine-induced increment in DNR accumulation (< 2-fold) was too small to explain the variations in drug sensitivity. Restriction enzyme-based assays and sequencing of partial topo II alpha and topo II beta cDNAs from the most highly resistant specimens failed to demonstrate topo II gene mutations that could account for resistance. Western blotting of marrow samples containing greater than 80% blasts revealed that the content of the two topo II isoenzymes varied over a greater than 20-fold range, but did not correlate with drug sensitivity in vitro or in vivo. In addition, levels of topo II alpha and topo II beta in 46 of 47 clinical samples were lower than in human AML cell lines. Immunoperoxidase staining showed that these low topo II levels were accompanied by marked cell-to-cell heterogeneity, with topo II alpha being abundant in some blasts and diminished or absent from others. There was a trend toward increasing percentages of topo II alpha-positive cells in pretreatment marrows that contained more S-phase cells. Consistent with this observation, treatment of patients with granulocyte-macrophage colony-stimulating factor for 3 days before chemotherapy resulted in increases in topo II alpha-positive cells concomitant with increases in the number of cells traversing the cell cycle. These observations have implications for the regulation of topo II in AML, for the use of topo II-directed chemotherapy, and for future attempts to relate drug sensitivity to topo II levels in clinical material.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Oestrogen-regulated genes in breast cancer: association of pLIV1 with lymph node involvement.
In order to isolate markers of oestrogen responsiveness in breast cancer, we have cloned a number of oestrogen-regulated genes. Two of these, pLIV1 and pLIV2 (pS2), have been shown to be predominantly expressed in oestrogen receptor (ER)+ tumours. In this study, we examined their expression in relation to various clinical and histopathological features of breast cancer, and showed that pLIV1, but not pS2, is significantly associated with lymph node involvement (P < 0.01), while pS2 is more frequently observed in premenopausal patients (P < 0.05). Subdivision of the pLIV1 data by ER and nodal status of the tumour identified a highly significant association between pLIV1 expression and lymph node involvement in ER-positive disease, with 15/24 (63%) ER+ pLIV1+ tumours showing nodal involvement. Conversely, 20/23 (87%) ER+ pLIV1- patients were lymph node-negative (P < 0.001). Subdivision of the pS2 data by ER status did not reach significance. The application of pLIV1 as a marker of lymph node involvement was further exemplified in small tumours (< < 2 cm), where 11/12 (92%) lymph node-positive patients expressed pLIV1, while 17/22 (77%) node-negative patients were pLIV1 negative (P < 0.001). Similarly, pLIV1 expression identified lymph node involvement in moderately differentiated tumours (P < 0.01), but was independent of vascular invasion. pLIV1 may, therefore, represent a candidate gene for metastatic spread in ER+ breast cancer.
Breast Neoplasms↗