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Biomedical subjects

V Santini

Publications and source records attributed to V Santini.

At least 19 recordsLinked to original sources
PubMed2001

Homoharringtonine: history, current research, and future direction.

BACKGROUND: Cephalotoxine esters, including homoharringtonine (HHT), have shown encouraging activity in leukemia in initial studies in China and in later studies in the U.S. METHODS: The authors conducted a review of the literature to examine the studies pertinent to HHT in relation to preclinical studies and Phase I-II trials in patients with hematologic malignancies and solid tumors. RESULTS: HHT and analogues appear to induce differentiation and apoptosis. Studies from China reported high response rates in patients with leukemia. Trials in the U.S. using short HHT infusions (3-4 mg/m(2) daily for 5 days) resulted in a high incidence of cardiovascular complications that were reduced using continuous infusion schedules of 3-7 mg/m(2) daily for 5-7 days initially, and later lower dose schedules of 2.5 mg/m(2) daily for 7-14 days. Results in solid tumors were negative. However encouraging results were reported in patients with acute myeloid leukemia, myelodysplastic syndrome, acute promyelocytic leukemia, and, most important, chronic myeloid leukemia (CML). In CML patients, HHT has been investigated alone and in combination with interferon-alpha and low-dose cytarabine in late and early chronic phases, with positive results. Additional areas of interest include the potential use of HHT for the treatment of central nervous system leukemia, polycythemia vera, and other nonmalignant conditions such as malaria. New semisynthetic preparations and HHT derivatives that bypass multidrug resistance may improve the efficacy and toxicity profiles, and broaden the range of antitumor efficacy. CONCLUSIONS: HHT and its derivatives appear to have promising activity in hematologic malignancies, a finding that needs to be pursued.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Changes in DNA methylation in neoplasia: pathophysiology and therapeutic implications.

Methylation of DNA is a biochemical modification that can influence gene expression and is involved in inactivating one of the two X chromosomes in women. Evidence that has accumulated in the past 10 years suggests that cancer cells usurp this physiologic mechanism and use it to their benefit by inactivating tumor suppressor genes and related proteins. However, the primary structure of the affected proteins remains intact; reversal of abnormalities in DNA methylation may therefore restore the tumor-suppressive function of these genes and provide a novel approach to cancer therapy. Two demethylating drugs, 5-azacytidine and 5-aza-deoxycytidine, are currently being tested in clinical trials, and several others are in preclinical development. In this article, the biological rationale for targeting aberrant methylation in cancer therapy is reviewed and completed phase I and II trials of this approach, some of which show promise for treatment of hematologic malignancies, are summarized.

5-Methylcytosine↗
PubMed2001

Amifostine: chemotherapeutic and radiotherapeutic protective effects.

Amifostine (Ethyoltrade mark, Alza Pharmaceuticals) is an inorganic thiophosphate cytoprotective agent known chemically as ethanethiol, 2-[3- aminopropyl)amino]dihydrogen phosphate. It is a prodrug of free thiol (WR-1065) that may act as a scavenger of free radicals generated in tissues exposed to cytotoxic drugs and binds to reactive metabolites of such drugs. Amifostine was originally developed as a radioprotective agent in a classified nuclear warfare project. Following declassification of the project it was evaluated as a cytoprotective agent against toxicity of the alkylating drugs and cisplatin. Differences in the alkaline phosphatase concentration of normal versus tumour tissues can result in greater conversion of amifostine in normal tissues. Inside the cell, WR-1065 provides an alternative target to DNA and RNA for the reactive molecules of alkylating or platinum agents and acts as a potent scavenger of the oxygen free radicals induced by ionizing radiation and some chemotherapy agents. Preclinical animal studies have demonstrated that the administration of amifostine protects against a variety of chemotherapy-related toxicities including cisplatin-induced nephrotoxicity, cisplatin-induced neurotoxicity, cyclophosphamide- and bleomycin-induced pulmonary toxicity and the cytotoxicities (including cardiotoxicity) induced by doxorubicin and related chemotherapeutic agents. Amifostine has been shown to protect a variety of animal species from lethal doses of radiation. Amifostine gives haematological protection from cyclophosphamide, carboplatin, mitomycin C, fotemustine and radiotherapy; renal and peripheral nerve protection from cisplatin; mucosa, skin and salivary gland protection from radiotherapy. Multiple Phase I studies were carried out with amifostine in combination with chemotherapy for various neoplasms. Appropriate doses of amifostine were found to be 740 - 910 mg/m(2) in single-dose regimens and 340 mg/m(2) in multiple-dose regimens. In radioprotection, doses are generally 200 - 350 mg/m(2). For all these characteristics, amifostine has been recently approved and suggested in ASCO clinical practice guidelines as a radioprotector for head and neck cancer treatment and supportive agent during cisplatin-based chemotherapy, in lymphomas and solid tumours. Moreover, its spectrum of possible applications is enlarging. As data have been provided indicating that amifostine stimulates haematopoiesis, it has been employed with intriguing results in the treatment of myelodysplastic syndromes (MDS).

Amifostine↗
PubMed2001

Searching for the magic bullet against cancer: the butyrate saga.

n-Butyric acid and its "polymorphic" derivatives have been largely but somehow "blindly" studied in oncology and in red cell diseases with consistent results through decades indicating a strong maturative effect determined by enhancement of gene transcription. Although these effects have been observed mainly in vitro, the relative absence of systemic toxicity of butyrates render these compounds appealing as specific therapeutic agents. More interestingly, their specific mechanism of action, i.e. inhibition of histone deacetylase and de-repression of transcription represents at present an unique tool for diseases such as acute leukemias which are characterised by a disregulation of co-repressors and co-activators of gene transcription. More insight into specificity and modalities of action of different butyrate derivatives may be a guarantee for excellent tailored antileukemic therapy in the future.

Antineoplastic Agents↗
PubMed2000

Amifostine in the treatment of low-risk myelodysplastic syndromes.

BACKGROUND AND OBJECTIVE: The phosphorylated aminothiol agent amifostine (Ethyol) protects bone marrow and other tissues from toxicity due to ionizing radiation and antineoplastic drugs, and stimulates progenitors from normal and myelodysplastic bone marrow. Contrasting results have been published so far on the effectiveness of amifostine in correcting cytopenia in patients with myelodysplastic syndromes (MDS). DESIGN AND METHODS: In a pilot phase II study we treated 26 patients with low risk MDS (13 RA, 2 RARS, 2 CMML, 9 RAEB with blasts < 10%) with amifostine (200 mg/m(2 )x 3/week for 4 weeks). RESULTS: Hemoglobin concentration, reticulocyte, neutrophil and platelet counts increased respectively in 6 (23%), 11 (42%), 13 (50%) and 9 (34%) of patients. Red cell transfusions were reduced (> 50%) in 4/26 patients and abolished in 1/26. Unexpectedly a significant decrease in soluble transferrin receptor level at week 4 of therapy, compared to the basal level (p<0.04), was observed in the whole population of patients. INTERPRETATION AND CONCLUSIONS: Amifostine can ameliorate cytopenia in some patients with MDS, with few and mild side effects. Neutropenia is more likely to be corrected than anemia or thrombocytopenia. Mechanisms underlying this biological effect remain to be clarified.

Aged↗
PubMed1999

Activity of vinorelbine on B-chronic lymphocytic leukemia cells in vitro.

Vinorelbine (VNR) is a new semi-synthetic Vinca rosea alkaloid that has been employed both in combination and as a single agent, showing a significant antitumour activity. Since little is known about VNR in human leukemia, we studied the in vitro cytotoxic effect of VNR on peripheral blood lymphocytes from 18 patients affected by B-chronic lymphocytic leukemia (CLL), employing the INT assay. VNR inhibited fresh B-CLL cells from 15/18 patients in primary cultures, the ID50 doses ranging from 4 ng/ml to 83 micrograms/ml. These data strongly suggest that VNR could be effective in the treatment of B-CLL.

Aged↗
PubMed1999

Regioselective synthesis and biological profiling of butyric and phenylalkylcarboxylic esters derivated from D-mannose and xylitol: influence of alkyl chain length on acute toxicity.

Regiospecific synthesis of 12 novel n-butyric and phenylalkylcarboxylic monoesters of mannose and xylitol was achieved. The strategy adopted, avoided a tedious intramolecular transesterification step, previously described for the synthesis of analogous compounds and permitted the facile synthesis of a new generation of stable derivatives. The general tolerance of the drugs has been assayed after intravenous administration of a bolus dose into mice. Monobutyric esters showed a low toxicity commensurate with the requirements for future development. A relationship was observed between chain length and toxicity. In contrast, phenylacetic, 3-phenylpropionic and 4-phenylbutyric esters were found to be toxic. Phenylbutyric esters induced marked and specific neuromuscular damage. Preliminary biological investigations of the new series of monobutyric esters showed them to retain the benificial biological properties of butyric acid whilst remaining relatively non toxic. They induced an inhibition of in vitro proliferation of 10 human cases of de novo acute myeloid leukemia (AML) primary cultures and AML established cell lines. AML blasts growth appeared to be blocked and cell differentiation was established. Transcription and expression of maturation markers and finally apoptosis were observed. Moreover, human gamma-chain hemoglobin (HbF) synthesis in erythroleukemia cells was stimulated by monobutyric esters. Mannose and xylitol butyric derivatives would appear to have exciting potential in treatment of beta-Hemoglobinopathies, sickle cell anemia and cancer.

Animals↗
PubMed1999

Sequential cis-platinum and fludarabine with or without arabinosyl cytosine in patients failing prior fludarabine therapy for chronic lymphocytic leukemia: a phase II study.

Patients with chronic lymphocytic leukemia (CLL) who fail fludarabine (Fluda) therapy have a poor response to subsequent salvage regimens and a poor prognosis. This study was undertaken to determine the efficacy and toxicity of a cis-platinum, (cis-p)fluda and arabinosyl cytosine (ara-C) combination in patients who were refractory to fluda or had relapsed following prior fluda therapy for CLL. Forty-one patients who had progressive CLL were treated on study. Eleven patients (27%) were sensitive to fluda and thirty (73%) refractory prior to study entry. Therapy consisted of cis-p 100 mg/m2 continuous intravenous (i.v.) infusion over 4 days, fluda 30 mg/m2 i.v. over 15 minutes on Days 3 and 4 either given alone (PF) or with ara-C 500 mg/m2 i.v. over 1 hour on Day 4 (PFA). The median number of PF or PFA courses received was two. No patient achieved a complete response. Eight patients (19%) achieved a partial response (PR), 28 were taken off study with progressive or refractory disease and 5 had induction deaths. The overall median survival was 6 months, 15 months in responding patients, and 4 months in non-responding patients. Rai stage I-II patients had a median survival of 7 months and stage III-IV patients had a median survival of 3 months. Major toxicities (myelosuppression, sepsis, renal failure and tumor lysis syndrome) were frequent. In conclusion, it can be said that the PF and PFA regimens have equivalent modest activity in patients with progressive CLL following prior fluda therapy, predominantly among patients whose disease was sensitive to fluda at last prior exposure. Ara-C did not add to the activity of the cis-p/fluda combination in this study group.

Adult↗
PubMed1999

Maturation and apoptosis of primary human acute myeloblastic leukemia cells are determined by TNF-alpha exclusively through CD120A stimulation.

BACKGROUND AND OBJECTIVE: Tumor necrosis factor-a plays an important role in hematopoiesis. Its effects are mediated through two membrane-bound receptors: TNF-R I (p55; CD 120a) and TNF-R II (p75; CD 120b). The aim of our study was to investigate the relative roles of these receptors. DESIGN AND METHODS: We analyzed in 16 acute myeloid leukemia cases whether TNF-alpha could induce in vitro maturation and apoptosis. We then investigated which of the two receptors was provoking monocytic maturation and which was responsible for apoptosis by using the agonistic MoAb HTR-9, directed at CD120a, and the CD120b antagonistic MoAb UTR-1. RESULTS: Monocytic maturation (morphologic and immunologic) was induced in all cases studied, although to different rates, by TNF-alpha and by HTR-9 incubation. The addition of UTR-1 to TNF-alpha did not abolish maturation, nor did it affect apoptosis, which was present in primary AML cultures after 4 and 10 days. INTERPRETATION AND CONCLUSIONS: We present here evidence that the sole stimulation of CD 120a, but not of CD120b, by TNF-alpha is responsible for bot monocytic maturation and apoptosis of primary AML blasts.

Antigens, CD↗
PubMed1999

Induction of apoptosis by monosaccharide butyrate stable derivatives in chronic lymphocytic leukemia cells.

BACKGROUND AND OBJECTIVE: Different therapeutic approaches are needed to restore apoptotic mechanisms in CLL cells, as present ones are not successful. We assessed the apoptotic effects of stable butyrate derivatives on CLL lymphocytes: in these molecules a mannose molecule is bound as ester to one-five butyrate moieties, conferring pharmacological stability to the pro-drugs which are able to induce apoptosis in primary AML blasts. DESIGN AND METHODS: Peripheral blood samples obtained from 17 patients with typical B-CLL were cultured in the presence of 0.5-1mM D1 (O-n-butanoyl-2, 3-O-isopropylidene-a-D-mannofuranoside), F1 (1-O-n-butanoyl-2, 3-O-isopropylidene-D,L-xylitol) and G1 (1-O-n-butanoyl-D,L-xylitol) derivatives for 4 days and equimolar sodium butyrate as comparison. After culture, apoptosis was evaluated by cell morphology, cellular DNA content, pattern of DNA fragmentation, annexin V exposure on cell membrane, and cell cycle parameters. Bcl2, bax, and fas oncogene expression were also evaluated by the APAAP method. RESULTS: The addition to cell cultures of D1 or F1 or G1 butyrate monosaccharides as well as sodium butyrate 0.5 and 1 mM determined to different extents an increase in the percentage of apoptotic cells in all CLL samples, relatively to the method and butyrate molecule added in culture. Heterogeneity in CLL cell sensitivity to the three butyrates was observed. Up to 60-68% apoptotic bodies were present in treated cultures after exposure to D1 0.5-1 mM, 60-72% after F1 0.5-1 mM and 48-60% after G1 0.5-1 mM. Comparison of untreated versus treated cultures yielded important significance (p< 0.001). At DNA content analysis, analyzed by flow cytometry, apoptotic events were accounting for up to 70-77% of D1-treated and 68-74% of F1-treated CLL cells at 0.5 and 1 mM concentrations (p= 0. 0001, vs controls 0-39%), and for 72-81% of G1 (0.5-1 mM) treated cells (overall, p=0.005). Cell cycle parameters were not altered by addition of butyrates, but expression of Annexin V was greatly enhanced. In a limited number of CLL cases fas, bcl2/bax ratio was analyzed and found unmodified. INTERPRETATION AND CONCLUSIONS: Monosaccharide butyrate stable derivatives are potent inducers of primary CLL cell apoptosis, both in untreated and alkylating agent pre-treated cases. Our results suggest that the apoptotic pathways elicited by butyrate in CLL lymphocytes are direct, specific and most probably do not involve bcl2/bax. Pro-apoptotic agents like the stable monosaccharide butyrate derivatives here studied could bring more insights into CLL biology and resistance to apoptosis, and possibly originate alternative treatments for CLL.

Aged↗
PubMed1999

The potential of amifostine: from cytoprotectant to therapeutic agent.

BACKGROUND AND OBJECTIVE: Amifostine is an inorganic thiophosphate cytoprotective agent known chemically as ethanethiol, 2-[(3-aminopropyl)amino]dihydrogen phosphate. It is a pro-drug of free thiol that may act as a scavenger of free radicals generated in tissues exposed to cytotoxic drugs, and binds to reactive metabolites of such drugs. Amifostine was originally developed as a radioprotective agent in a classified nuclear warfare project. Following declassification of the project it was evaluated as a cytoprotective agent against toxicity of the alkylating drugs and cisplatin. In fact, pretreatment with amifostine was well tolerated and reduced the cumulative hematologic, renal and neurological toxicity associated with cisplatin, cyclophosphamide and vinblastine therapy of advanced and metastatic solid tumors. The objective of this review is to focus the importance of amifostine as a myeloprotective and cytoprotective drug during treatment with chemotherapeutics, presenting the most recent results, and to discuss the application of amifostine in the therapy of myelodysplastic syndromes. EVIDENCE AND INFORMATION SOURCES: The material analyzed in this study includes data published or under publication by the authors as full papers or clinical protocols. Articles and abstracts published in Journals covered by Medline constitute the other source of information. STATE OF THE ART AND PERSPECTIVES: Amifostine, formerly known as WR-2721, is an organic thiophosphate that was developed to protect normal tissues selectively against the toxicities of chemotherapy and radiation. Amifostine is a pro-drug that is dephosphorylated at the tissue site to its active metabolite by alkaline phosphatase. Differences in the alkaline phosphatase concentrations of normal versus tumor tissues can result in greater conversion of amifostine in normal tissues. Once inside the cell the free thiol provides an alternative target to DNA and RNA for the reactive molecules of alkylating or platinum agents and acts as a potent scavenger of the oxygen free radicals induced by ionizing radiation and some chemotherapies. Preclinical animal studies demonstrated that the administration of amifostine protected against a variety of chemotherapy-related toxicities including cisplatin-induced nephrotoxicity, cisplatin-induced neurotoxicity, cyclophosphamide- and bleomycin-induced pulmonary toxicity, and the cytotoxicities (including cardiotoxicity) induced by doxorubicin and related chemotherapeutic agents. Amifostine was shown to protect a variety of animal species from lethal doses of radiation. Studies in tumor-bearing animals demonstrated that the administration of amifostine results in cytoprotection without loss of antitumor activity. Multiple phase I studies were carried out with amifostine in combination with chemotherapy for various neoplasms. Appropriate doses of amifostine resulted to be 740-910 mg/m(2) in a single dose regimen, and 340 mg/m(2) in a multiple dose regimen. Amifostine afforded not only hematologic protection, but also other organ protection from cytotoxic agents such as nephrotoxicity, mucositis and peripheral neuropathy from cisplatin. Many studies have been performed to investigate cytoprotective efficacy of amifostine. In brief, amifostine gives hematologic protection from cyclophosphamide, carboplatin, mitomycin C, fotemustine and radiotherapy; renal and peripheral nerve protection from cisplatin; mucosa, skin, and salivary gland from radiotherapy. In phase I/II studies these properties have been confirmed, together with a generally good tolerability of the drug, hypotension being the most common side effect. It has been observed that amifostine possibly enhances the anti-tumor effect of carboplatin, nitrogen mustard, melphalan, and cisplatin combined with 5-FU or vinblastine. For all these characteristics, amifostine is at present broadly used as supportive treatment during chemotherapy, in lymphomas and solid tumors, and its spec

Amifostine↗
PubMed1999

Immunohistochemistry applied to the study of bone marrow Gaucher's cells: a case report.

Gaucher's disease is frequently associated with immunologic abnormalities, e.g. hypergammaglobulinemia, polyclonal gammopathy and benign monoclonal gammopathy. A patient with Gaucher's disease and a selective accumulation of IgM k in Gaucher's cells without serum monoclonal gammopathies is described. The selective accumulation is detected by immunohistochemistry analysis performed on cryostat bone marrow biopsies.

Adult↗
PubMed1998

Proliferation signaling and activation of Shc, p21Ras, and Myc via tyrosine 764 of human granulocyte colony-stimulating factor receptor.

The membrane-distal region of the cytoplasmic domain of human granulocyte colony-stimulating factor receptor (G-CSF-R) contains four conserved tyrosine residues: Y704, Y729, Y744, and Y764. Three of these (Y729, Y744, and Y764) are located in the C-terminal part of G-CSF-R, previously shown to be essential for induction of neutrophilic differentiation. To determine the role of the tyrosines in G-CSF-mediated responses, we constructed tyrosine-to-phenylalanine (Y-to-F) substitution mutants and expressed these in a differentiation competent subclone of 32D cells that lacks endogenous G-CSF-R. We show that all tyrosines can be substituted essentially without affecting the differentiation signaling properties of G-CSF-R. However, substitution of one specific tyrosine, ie, Y764, markedly influenced proliferation signaling as well as the timing of differentiation. 32D cells expressing wild-type (WT) G-CSF-R (or mutants Y704F, Y729F, or Y744F) proliferated in G-CSF-containing cultures until day 8 and then developed into mature neutrophils. In contrast, 32D/Y764F cells arrested in the G1 phase of the cell cycle within 24 hours and showed complete neutrophilic differentiation after 3 days of culture. This resulted in an average 30-fold reduction of neutrophil production as compared with the 32D/WT controls. Importantly, G-CSF-mediated activation of Shc, p21Ras and the induction of c-myc were severely reduced by substitution of Y764. These findings indicate that Y764 of G-CSF-R is crucial for maintaining the proliferation/differentiation balance during G-CSF-driven neutrophil development and suggest a role for multiple signaling mechanisms in maintaining this balance.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Butyrate-stable monosaccharide derivatives induce maturation and apoptosis in human acute myeloid leukaemia cells.

The rapid degradation and subsequent lack of efficacy of n-butyric acid in vivo has been improved by the synthesis of monosaccharide stable pro-drugs of butyric acid. We studied the effects of D1 (O-n-butanoyl-2,3-O-isopropylidene-alpha-D-mannofuranoside), G1 (1-O-n-butanoyl-D,L-xylitol), and F1 (1-O-n-butanoyl 2,3-O-isopropylidene-D,L-xylitol) on the maturation and proliferation of AML cell lines HL 60 and FLG 29.1 and of purified blast cells from 10 cases of de novo acute myeloid leukaemia (AML). AML cell maturation was measured by surface antigen expression, morphology and cytochemistry. Toxicology in mice was also evaluated (DL50 1000 mg/kg). In HL 60 cells G1 and D1 increased the expression of CD15 and CD11a (presenting 62% of promyelo-metamyelocytes), and in 7/10 cases of primary AMLs that of CD11a, CD11b, CD15, and myeloperoxidase. D1, G1 and F1 induced a dose-dependent inhibition of tritiated thymidine uptake. Apoptosis (evaluated by flow cytometry and agarose gel electrophoresis) was induced in AML blasts by D1 and F1 (79% and 94% respectively for HL 60 cells) and, with less effect, by G1 (27%). The persistence of maturative and apoptotic activity in these new pro-drugs of butyric acid, hydrolysed only inside the tumour cell, suggests a possible use in differentiation therapy of myelodysplastic syndromes and AMLs.

Acute Disease↗
PubMed1998

Coexpression of erythroid and megakaryocytic genes in acute erythroblastic (FAB M6) and megakaryoblastic (FAB M7) leukaemias.

There is evidence to suggest a close relationship between the erythroid and megakaryocytic lineages. Using RT-PCR, we evaluated the coexpression of erythroid and megakaryocytic genes in blasts from 25 acute myeloid leukaemia (AML) cases (FAB M1-M7) and three unclassifiable leukaemias with trilineage dysplasia (trilineal AML). All FAB M6 and M7 and trilineal leukaemias expressed mRNAs for alpha-globin, glycoprotein IIb (GpIIb), erythropoietin receptor (Epo-R) and thrombopoietin receptor (c-mpl), but not for myeloperoxidase (MPO) which in contrast was expressed in the other FAB-subtype leukaemias. These data support the hypothesis that blasts from M7 and M6 leukaemias may derive from (or represent) a common progenitor cell with resident bipotentiality towards the megakaryocytic and erythrocytic lineages.

Base Sequence↗