Biomedical subjects

G Zon

Publications and source records attributed to G Zon.

At least 19 recordsLinked to original sources

PubMed2001

Safety of intracoronary administration of c-myc antisense oligomers after percutaneous transluminal coronary angioplasty (PTCA).

We wished to assess the clinical safety and pharmacokinetics of ascending doses of a synthetic oligodeoxynucleotide (LR-3280) administered after coronary angioplasty. Antisense oligodeoxynucleotides designed to hybridize with target messenger ribonucleic acid (mRNA) in a complementary fashion to inhibit the expression of corresponding protein also have the ability to bind to extracellular growth factors. LR-3280 has been shown to reduce c-myc expression, inhibit growth and collagen biosynthesis in human vascular cells, and reduce neointimal formation in animal models of vascular injury. After successful percutaneous transluminal coronary angioplasty (PTCA), 78 patients were randomized to receive either standard care (n = 26) or standard care and escalating doses of LR-3280 (n = 52) (doses from 1 to 24 mg), administered into target vessel through a guiding catheter. Overall safety was evaluated by clinical adverse events, laboratory tests, and electrocardiograms. Patency was evaluated by quantitative coronary angiography. There were no clinically significant differences between treated and control patients. No adverse effects of LR-3280 on the patency of dilated coronary arteries were observed. Pharmacokinetic data revealed that peak plasma concentrations of LR-3280 occurred at 1 minute over the studied dose range and rapidly decreased after approximately1 hour, with little LR-3280 detected in the urine between 0-6 hours and 12-24 hours. The intracoronary administration of LR-3280 is well tolerated at doses up to 24 mg and produces no adverse effects in dilated coronary arteries. These results provide the basis for the evaluation of local delivery of this phosphorothioate oligodeoxynucleotide for the prevention of human vasculoproliferative disease.

Aged↗

PubMed1999

Enhanced anti-tumor effects with microencapsulated c-myc antisense oligonucleotide.

A phosphorothioate c-myc antisense oligonucleotide was complexed with zinc and encapsulated into injectable biodegradable microspheres. The efficacy of this novel formulation was compared with intravenous administration of the unencapsulated drug in human melanoma and leukemia xenografts in immunocompromised mice. The microencapsulated formulation was more effective as shown by reduced tumor growth, a decreased number of metastases, reduced c-myc expression, and increased survival in the melanoma model, and decreased metastatic potential and increased survival in the leukemia model. These results show that, as has been demonstrated previously with protein and peptide drugs, greater therapeutic efficacy can be obtained when antisense oligonucleotides are delivered from sustained-release formulations.

Animals↗

PubMed1999

Comparison of binding of N3'-->P5' phosphoramidate and phosphorothioate oligonucleotides to cell surface proteins of cultured cells.

The binding of uniformly modified N3'-->P5' phosphoramidate and stereorandom and stereopure phosphorothioate oligonucleotides (ODN) to cell surface proteins was studied, using both a fibroblast and an epithelial cell line, to assess the effect of different analog backbone types and base composition on cell surface protein binding. Marked differences were observed, both quantitative and qualitative, in the proteins to which individual ODN bound. One phosphoramidate, antisense to the insulin-like growth factor-1 (IGF-1) receptor (IGF-1R), bound to different proteins than did either a 6-base mismatch phosphoramidate IGF-1R sequence or a sense N-ras sequence. The latter bound poorly to the fibroblast line and predominantly to a 46 kDa protein in the epithelial line, as did many of the other ODN. This binding was not so marked as that of the isosequential end-capped phosphodiester N-ras sequence, which bound to this protein in both cell lines. Stereopure and stereorandom phosphorothioates containing a G-quartet (shown in other studies to form high-order tetrad structures), antisense to c-myc, exhibited considerable nonspecific binding to many proteins, as did the isosequential phosphoramidate. In particular, this ODN sequence gave notable binding to high molecular weight proteins. In general, binding of the c-myc ODN to proteins of 28-30, 46, 67, and 70-90 kDa was found in this study.

3T3 Cells↗

PubMed1999

Preclinical and clinical experience of antisense therapy for solid tumors.

The mechanisms by which the therapeutic window and clinical utility of antisense drugs can be fully optimized are discussed. Recent preclinical and clinical efforts are focusing on defining and optimizing the combination therapy regimes in which ONs are most efficacious. However, additional research is required to define which, and how, oncogenes interact with each other and the circumstances under which synergistic therapeutic benefit might be achieved using antisense drugs. The therapeutic window of antisense drugs is also being expanded by the use of novel delivery systems, including lipid-based carriers for systemic delivery. Taken together, molecular therapeutics based on antisense technology, coupled with effective delivery systems increasing drug potency, are anticipated to substantially improve the treatment of human neoplasms.

Animals↗

PubMed1998

c-myc antisense oligodeoxynucleotides enhance the efficacy of cisplatin in melanoma chemotherapy in vitro and in nude mice.

This study was designed to assess the efficacy of a new antimelanoma therapeutic strategy that relies on the use of a c-myc antisense 15-mer phosphorothioate oligodeoxynucleotide ([S]ODN), in combination with cisplatin (cis-diamminedichloroplatinum; DDP), which is currently used in the clinical management of melanoma patients. Proliferation and colony formation of melanoma cells were both inhibited by the DDP/c-myc antisense [S]ODN combination to a greater extent than that observed with either agent alone. Inhibition was most effective when DDP was followed by c-myc antisense [S]ODNs. Cell cycle flow cytometric analysis of cells exposed to the two agents either alone or in combination demonstrated that (a) c-myc antisense [S]ODNs induced an accumulation of cells in S phase and apoptosis in a fraction of the cells, detectable at day 5 after the beginning of treatment; (b) DDP induced a block in G2-M phase detectable at day 1, which was partially recovered, and apoptosis similar in extent to that induced by c-myc antisense [S]ODNs; and (c) DDP and c-myc antisense [S]ODNs together induced arrest in G2-M phase, which was maximum at day 3, i.e., delayed as compared to the block induced by DDP. The combination induced a higher percentage of apoptosis, evident at day 3 from the start of treatment, that correlated with a marked reduction in Bcl-2 expression. Mice bearing human melanoma xenografts and treated sequentially with DDP and c-myc antisense [S]ODNs showed a higher inhibition of tumor growth, reduction in the number of lung metastases, and increase in life span compared with those treated with either agent alone. Together, these data lend support to the development of anticancer therapies involving oncogene-targeted antisense ODNs and conventional antineoplastic drugs.

Animals↗

PubMed1997

Hydration effects on the duplex stability of phosphoramidate DNA-RNA oligomers.

Recent studies on uniformly modified oligonucleotides containing 3'-NHP(O)(O-)O-5'internucleoside linkages (3'amidate) and alternatively modified oligonucleotides containing 3'-O(O-)(O)PNH-5'internucleoside linkages (5'amidate) have shown that 3'amidate duplexes, formed with DNA or RNA complementary strands, are more stable in water than those of the corresponding phosphodiesters. In contrast, 5'amidates do not form duplexes at all. There is no steric reason that the 5'amidate duplex should not form. We demonstrate that these differences arise from differential solvation of the sugar-phosphate backbones. By molecular dynamics calculations on models of 10mer single-stranded DNA and double-stranded DNA-RNA molecules, both with and without the phosphoramidate backbone modifications, we show that the single-stranded 3'amidate and 5'amidate backbones are equally well solvated, but the 5'amidate backbone is not adequately solvated in an A-form duplex. These results are supported by quantum chemical free energy of solvation calculations which show that the 3'amidate backbone is favored relative to the 5'amidate backbone.

Amides↗

PubMed1997

Phosphorothioate oligodeoxynucleotides: large-scale synthesis and analysis, impurity characterization, and the effects of phosphorus stereochemistry.

Large-scale synthesis of phosphorothioate oligodeoxynucleotides on Tentagel using a 'batch mode' synthesizer and beta-cyanoethyl phosphoramidite coupling followed by sulfurization with bis(O,O-diisopropoxy phosphinothioyl) disulfide (S-tetra) provides stepwise yields of 98-99% and results in phosphorothioate oligodeoxynucleotides that are 93-97% pure, as determined by PAGE, after reverse-phase high performance liquid chromatography (RP-HPLC) and 'downstream' processing. The purity of phosphorothioate oligodeoxynucleotides synthesized on Tentagel is significantly higher than those synthesized on controlled pore glass. Electrospray ionization mass spectrometry of the n-1 impurity isolated by preparative PAGE was used to establish that the n-1 impurity is a heterogeneous mixture of all possible single-deletion sequences, relative to the parent phosphorothioate oligodeoxynucleotide, and results from minor, though repetitive, imperfections in the synthesis cycle. Acid-catalysed depurination was found to occur both during the synthesis and during the post-synthesis detritylation, following RP-HPLC. Studies of hybridization affinity and biological mechanism of action using independently synthesized n-1 phosphorothioate oligodeoxynucleotides relative to the 15 mer LR-3280 showed that, in this case, the majority of the n-1 sequences had more than a 10 degrees C decrease in melting temperature with sense RNA compared to the n-mer, and they did not cause detectable cleavage of RNA by RNase H in HL-60 human promyelocytic leukaemia cells. P stereoregular phosphorothioate oligodeoxynucleotides are not significantly more active than their stereorandom counterparts and thus their use in clinical studies seems unwarranted.

Humans↗

PubMed1996

Antisense oligodeoxynucleotide combination therapy of primary chronic myelogenous leukemia blast crisis in SCID mice.

The proliferation of chronic myelogenous leukemia (CML) cells and the transformation of normal hematopoietic cells by BCR-ABL appear to require the expression of a functional MYC protein, suggesting an approach to treatment of Philadelphia leukemias based on simultaneous targeting of BCR-ABL and c-MYC. To test this hypothesis, CML-blast crisis (CML-BC) primary cells were treated in vitro with bcr-abl and c-myc antisense phosphorothioate oligodeoxynucleotides ([S]ODNs), individually or in combination. Compared with antisense ODNs targeting of individual oncogenes, downregulation of both BCR-ABL and c-MYC by specific antisense [S]ODNs resulted in a synergistic antiproliferative effect. Colony formation of normal bone marrow cells was not affected by either treatment. To assess the therapeutic potential of multiple oncogene downregulation, SCID mice injected with CML-BC primary cells were treated systematically with equal doses of bcr-abl or c-myc antisense [S]ODNs or with a combination of both antisense [S]ODNs. Compared with mice treated with individual compounds, the disease process was significantly retarded in the group treated with both [S]ODNs as revealed by flow cytometry, clonogenic assay, and RT-PCR analysis to detect leukemic cells in mouse tissue cell suspensions. These effects correlated with a markedly increased survival of leukemic mice treated with both antisense [S]ODNs. Leukemic cells harvested from antisense [S]ODN-treated mice were sensitive to the effects of antisense [S]ODNs in vitro, suggesting that the treatment can be successfully repeated. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.

Animals↗

PubMed1996

Antitumor effect of c-myc antisense phosphorothioate oligodeoxynucleotides on human melanoma cells in vitro and and in mice.

BACKGROUND: Phosphorothioate oligodeoxynucleotides ([S]ODNs) contain a modified internucleoside phosphate backbone. Antisense [S]ODNs targeted to specific oncogenes have been used with some therapeutic success in animal models human leukemia; however, the potential for antisense [S]ODN treatment of solid tumors has only recently been explored. PURPOSE: We evaluated the effects of antisense [S]ODNs targeted to the c-myc oncogene on the proliferation of human melanoma cells in vitro and on the growth of human melanoma xenografts in CD-1 nude (nu/nu) mice, METHODS: The effects of 15-mer [S]ODNs containing c-myc sense, c-myc antisense, and two different scrambled sequences on the proliferation and viability of cultures of three established human melanoma cell lines (M14, JR8, and PLF2) were determined by measuring cell numbers and use of the trypan blue exclusion test. The induction of apoptosis in these cells following treatment with [S]ODNs was evaluated by fluorescence-activated cell sorter (FACS) analysis. FACS analysis was also used to determine the effects of [S]ODN treatment on the proliferation of primary cultures of a human melanoma explant (NG cells). The expression of c-Myc protein in cultured NG cells after treatment with [S]ODNs was examined by western blot analysis. The antitumor activity and the toxic effects of several [S]ODN treatment regimens were monitored by measuring differences in tumor weight (percent tumor weight inhibition), tumor growth rate (tumor growth inhibition), animal lifespan (percent increase in lifespan), the number of toxic deaths and the median number of long metastases in treated and control mice bearing NG xenografts. c-Myc protein expression in NG tumor cells following [S]ODN treatment was evaluated by FACS analysis, and the extent of apoptosis in these cells was determined by FACS analysis and morphologic examination. RESULTS: Treatment with antisense [S]ODNs, but not the others, inhibited the growth of all tested melanoma cultures in vitro; FACS analysis revealed that growth inhibition was associated with the induction of apoptosis. Antisense [S]ODN treatment also led to reduced celluLar levels of c-Myc protein. In vivo, [S]ODN antitumor activity and toxicity were dose and schedule dependent; however, only antisense [S]ODNs exhibited antitumor activity. Mice bearing NG xenografts treated with antisense [S]ODNs showed a marked inhibition of tumor growth, a reduction in the number of long metastases, and an increase in life span. Reduced levels of c-Myc protein and increased levels of apoptosis were also observed in NG tumor cells following antisense [S]ODN treatment. CONCLUSIONS: treatment of human melanoma cells and solid tumors with antisense [S]ODNs targeted to c-Myc inhibits their growth and is associated with the induction of apoptosis.

Animals↗

PubMed1996

Development of a novel scintillation proximity competitive hybridization assay for the determination of phosphorothioate antisense oligonucleotide plasma concentrations in a toxicokinetic study.

A novel scintillation proximity competitive hybridization assay was developed for determining plasma concentrations of compound 4003W94, a 15-base phosphorothioate antisense deoxyribonucleotide that is currently under preclinical evaluation for the treatment of restenosis following coronary artery angioplasty. The principle of the assay involves the hybridization binding of antisense (4003W94) to a biotinylated sense oligonucleotide to form a double-stranded nucleic acid complex on the surface of scintillation proximity beads derivatized with streptavidin. As in a competitive radioimmunoassay, there is an inverse relationship between the amount of radioactivity in the final binding complex and the amount of 4003W94 present in the sample being analyzed. Because this is a homogenous assay, no physical separation of bound from free radioligand is necessary. Conventional cross-reactivity studies with either 3'- or 5'-deletion oligomers of 4003W94 indicated that cross-reactivity generally decreased with each base deletion. The assay was used to determine plasma concentrations of 4003W94 equivalents in rhesus monkeys during an exploratory 14-day toxicity study. This method conceivably could be adapted for use as an effective in vitro screening tool for the identification of potential antisense oligonucleotide drug candidates or as a diagnostic tool for the detection of pathological disorders.

Analysis of Variance↗

PubMed1996

B-cell proliferation and differentiation in common variable immunodeficiency patients produced by an antisense oligomer to the rev gene of HIV-1.

The immunostimulatory activity of a phosphorothioate oligodeoxynucleotide (27 mer) that is antisense to the rev gene of HIV-1 was studied on normal human lymphocytes and on cells from patients with common variable immunodeficiency (CVI). For peripheral blood mononuclear cells from nine normal individuals, the proliferation index (16.8 +/- 12.5) after anti-rev oligomer exposure was proportional to the percentage of peripheral B-cells (r = 0.76, P = 0.02). In five experiments, enriched B- or T-cell populations had proliferation indices of 47.2 +/- 32.9 and 2.4 +/- 1.9, respectively. The addition of T-cells to anti-rev oligomer treated B-cells had no effect (proliferation index = 47.5 +/- 38.1). After anti-rev oligomer stimulation, autoradiography, and counterstaining for B- and T-cell markers, all detectable [3H]thymidine uptake was by CD19-positive cells. Eight of the 14 CVI patients had a proliferation index and secreted levels of IgM and IgG comparable to cells from normal individuals. In contrast to normal cells, the direct correlation between proliferation of peripheral blood mononuclear cells and the percentage of peripheral B-cells was weak in samples from 13 CVI patients (r = 0.4, P = 0.2). These findings indicate that peripheral blood B-cells from about half of CVI patients proliferate and produce immunoglobulin after exposure to anti-rev oligomer. These data demonstrate that under the appropriate circumstances, B-cells of some CVI patients can proliferate and differentiate normally.

B-Lymphocytes↗

PubMed1996

Amplification of antibody production by phosphorothioate oligodeoxynucleotides.

A phosphorothioate oligodeoxynucleotide that is complementary (antisense) to the initiation region of the rev gene of HIV-1 causes hypergammaglobulinemia and splenomegaly in mice, and it induces B cell proliferation and differentiation in mouse spleen mononuclear cells (SMNCs) and human peripheral blood mononuclear cells in vitro. The current studies were performed to investigate the specificity of these immunomodulatory effects. Both the sense and antisense rev oligomers stimulated tritiated thymidine incorporation and secretion of immunoglobulin M (IgM) and immunoglobulin G (IgG) by mouse SMNCs in a concentration-dependent fashion, but the antisense oligomer produced greater immune effects. Studies comparing phosphorothioate oligomers (anti-rev, c-myc, and c-myb) either methylated or unmethylated at CpG dinucleotides showed that methylation effectively abrogated the proliferative effect and tended to reduce the immunoglobulin secretory activity, but the latter was not statistically significant except in the case of IgG in anti-rev oligomer-treated cultures. Mice were injected with the sense or antisense rev oligomers singly or in combination. The animals then were immunized with tetanus toxoid and received a booster 21 days later. Oligodeoxynucleotide-treated mice had significantly higher levels of IgM antibodies on days 28 and 35 and of IgG antibodies on days 14 and 35 as compared with mice that were immunized but received vehicle alone. There was no evidence for additive, synergistic, or antagonistic interactions of the sense and antisense rev oligomers. These results indicate that the unmethylated anti-rev oligomer is the most potent of the phosphorothioate oligomers tested at activating lymphocyte proliferation and differentiation and that a single intravenous injection of this oligodeoxynucleotide augments antibody production to a specific antigen as long as 35 days later.

Animals↗

PubMed1996

Effect of cisplatin and c-myb antisense phosphorothioate oligodeoxynucleotides combination on a human colon carcinoma cell line in vitro and in vivo.

We investigated the effect of c-myb antisense phosphorothioate oligodeoxynucleotides [(S)ODNs] and cisplatin (CDDP) combination on the human colon carcinoma cell line LoVo Dx both in vitro and in nude mice bearing LoVo Dx solid tumour. We show that antisense (S)ODN treatment decreases c-myb mRNA and protein expression, induces growth arrest in the G1 phase of the cell cycle, and inhibits cell proliferation. In vivo treatment with c-myb antisense (S)ODNs results in a reduction in tumour growth. A greater inhibition of cell proliferation in vitro and a higher increase of tumour growth inhibition and growth delay in vivo were obtained with the combination of (S)ODNs and CDDP than when the two agents were administered separately. This comparative study, using the same tumour cell line in vitro and in vivo, suggests that c-myb antisense (S)ODNs might be useful in the therapy of colon cancer in combination with antineoplastic drugs.

Animals↗

PubMed1996

An in vitro messenger RNA binding assay as a tool for identifying hybridization-competent antisense oligonucleotides.

The apparent dissociation constants for 32 phosphodiester and 5 phosphorothioate antisense oligodeoxyribonucleotides (ODN) targeted to murine tumor necrosis factor-alpha (mTNF-alpha) mRNA were determined using a gel-shift binding assay. In this assay, radiolabeled ODN were hybridized in solution to a structured mRNA transcript generated in vitro. Free ODN was resolved from bound ODN on a two-phase discontinuous polyacrylamide gel. Excision of gel slices containing free ODN or bound ODN, followed by Cerenkov counting of the slices, was used to prepare apparent binding isotherms for each ODN. Apparent dissociation constants for the anti-mTNF-alpha ODN varied from > 100 microM to 0.4 nM. Slight differences in RNA target site position resulted in significant differences in apparent affinity, particularly for shorter (12-mer) ODN. This binding assay provides an empirical means for selecting ODN sequences possessing high affinity for a target RNA and lends itself to a high throughput assay in which all possible antisense sequences of a given length can be evaluated to obtain the better binders for use in cell culture or in vivo.

Electrophoresis, Polyacrylamide Gel↗

PubMed1996

Phase I trial of an antisense oligonucleotide OL(1)p53 in hematologic malignancies.

PURPOSE: The phosphoprotein p53 is involved in transcriptional regulation and is detected in hematologic malignancies. In vitro incubation of acute myelogenous leukemia with OL(1)p53, a 20-mer phosphorothioate oligonucleotide complementary to p53 mRNA, results in leukemic cell death. A phase I dose-escalating trial was conducted to determine the toxicity of OL(1)p53 following systemic administration to patients with hematologic malignancies. PATIENTS AND METHODS: Sixteen patients with either refractory acute myelogenous leukemia (n = 6) or advanced myelodysplastic syndrome (n = 10) participated in the trial. Patients were given OL(1)p53 at doses of 0.05 to 0.25 mg/kg/h for 10 days by continuous intravenous infusion. RESULTS: No specific toxicity was directly related to the administration of OL(1)p53. One patient developed transient nonoliguric renal failure. One patient died of anthracycline-induced cardiac failure. Approximately 36% of the administered dose of OL(1)p53 was recovered intact in the urine. Plasma concentrations and area under the plasma concentration curves were linearly correlated with dose. Leukemic cell growth in vitro was inhibited as compared with pretreatment samples. There were no clinical complete responses. CONCLUSION: A phosphorothioate oligonucleotide, OL(1)p53, can be administered systemically without complications. This type of modified oligonucleotide can be administered without complete degradation, as it was recovered from the urine intact. This oligonucleotide may be useful in combination with currently available chemotherapy agents for the treatment of malignancies.

Adult↗

PubMed1995

Leukemia treatment in severe combined immunodeficiency mice by antisense oligodeoxynucleotides targeting cooperating oncogenes.

Transformation of hematopoietic cells by the p210bcr/abl tyrosine kinase appears to require the expression of a functional MYC protein, suggesting that simultaneous targeting of BCR-ABL and c-myc might be a rational strategy for attempting treatment of Phil-adelphia leukemia. To test this hypothesis, severe combined immunodeficiency mice injected with Philadelphia leukemic cells were treated systemically with equal doses of bcr-abl or c-myc antisense oligodeoxynucleotides (ODNs) or with both ODNs in combination. Compared with the mice treated with individual agents, the disease process was much slower in the group treated with both ODNs, as revealed by flow cytometry, clonogenic assay, and reverse transcriptase-polymerase chain reaction analysis to detect leukemic cells in mouse tissue cell suspensions, and by enumeration of liver metastases. The retardation of the disease process was positively correlated with a markedly increased survival of leukemic mice treated with both ODNs. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.

Animals↗

PubMed1995

Phosphatidylinositol-3 kinase activity is regulated by BCR/ABL and is required for the growth of Philadelphia chromosome-positive cells.

The BCR/ABL oncogenic tyrosine kinase is responsible for initiating and maintaining the leukemic phenotype of Philadelphia chromosome (Ph1)-positive cells. Phosphatidylinositol-3 (PI-3) kinase is known to interact with and be activated by receptor and nonreceptor tyrosine kinases. We investigated whether PI-3 kinase associates with and/or is regulated by BCR/ABL, whether this interaction is functionally significant for Ph1 cell proliferation, and, if so, whether inhibition of PI-3 kinase activity can be exploited to eliminate Ph1-positive cells from bone marrow. We show that the p85 alpha subunit of PI-3 kinase associates with BCR/ABL and that transient expression of BCR/ABL in fibroblasts and down-regulation of BCR/ABL expression using antisense oligodeoxynucleotides (ODNs) in Ph1 cells activates and inhibits, respectively, PI-3 kinase enzymatic activity. The use of specific ODNs or antisense constructs to downregulate p85 alpha expression showed a requirement for p85 alpha subunit in the proliferation of BCR/ABL-dependent cell lines and chronic myelogenous leukemia (CML) primary cells. Similarly, wortmannin, a specific inhibitor of the enzymatic activity of the p110 subunit of PI-3 kinase, inhibited growth of these cells. The growth of normal bone marrow and erythromyeloid, but not megakaryocyte, progenitors was inhibited by p85 alpha antisense [S]ODNs, but wortmannin, at the concentrations tested, did not affect normal hematopoiesis. The proliferation of two BCR/ABL- and growth factor-independent cell lines was not affected by downregulation of the expression of the p85 alpha subunit or inhibition of p110 enzymatic activity, confirming the specificity of the observed effects on Ph1 cells. Thus, PI-3 kinase is one of the downstream effectors of BCR/ABL tyrosine kinase in CML cells. Moreover, reverse transcriptase-polymerase chain reaction performed on single colonies to detect BCR-ABL transcripts showed that wortmannin was able to eliminate selectively CML-blast crisis cells from a mixture of normal bone marrow and Ph1 cells.

Androstadienes↗

PubMed1995

Sequence specificity on the growth suppression and induction of apoptosis of chronic myeloid leukemia cells by BCR-ABL anti-sense oligodeoxynucleoside phosphorothioates.

Sequence specificity of inhibitory effects of various BCR-ABL anti-sense oligodeoxynucleoside phosphorothioates (AS PS-ODN) on the proliferation of the chronic myeloid-leukemia cell line BV173 was examined. We confirmed that 26, 18, and 16mer B2A2 AS PS-ODN had strong inhibitory effects on the proliferation of BV173 cells with B2A2 mRNA expression, and that B3A2 AS PS-ODN were equally inhibitory when cultures were initiated at lower cell concentrations. However, at higher cell concentrations, the inhibitory effects by B3A2 AS PS-ODN were reduced and B2A2 AS PS-ODNs could suppress the proliferation of BV173 cells with much more relative sequence specificity. The 26mer B2A2 AS PS-ODN induced apoptosis of BV173 cells following reduction of BCR-ABL mRNA expression and p210 protein synthesis. Various sense (S), reverse order, and random sequences had no inhibitory effects except 16mer B2A2 S and B3A2 S that revealed significant suppressive effects. Furthermore, 26mer B3A2 AS also reduced B2A2 mRNA expression and p210 protein synthesis, while 16mer S sequences did not. These results suggest that B2A2 AS may be cross-reactive with B3A2 AS on the growth suppression of CML cells under certain culture conditions, possibly due to their partial hybridization to the ABL portion of the target mRNA, although other non-sequence-specific mechanisms are also possible.

Base Sequence↗