Clinical profile and outcome of cardiomyopathies in infants and children seen at a tertiary centre

INTRODUCTION

Due to their rare prevalence and marked heterogeneity, pediatric cardiomyopathies (CMPs) are little known and scarcely reported. We report the etiology, clinical profile and outcome of a consecutive cohort of children diagnosed with CMP and followed at Meyer Children's Hospital over a decade.

PATIENTS AND METHODS

We retrospectively reviewed patients consecutively referred from May 2008 to May 2019 for pediatric onset CMP (<18 years). Heart disease caused by arrhythmic disorders, toxic agents, rheumatic conditions and maternal disease were excluded.

RESULTS

We enrolled 110 patients (65 males), diagnosed at a median age of 27 [4-134] months; 35% had an infant onset (<1 year of age). A positive family history was more often associated with childhood-onset (38.8%). Hypertrophic cardiomyopathy (HCM; 48 patients) was the most frequent phenotype, followed by dilated cardiomyopathy (DCM; 35 patients). While metabolic and idiopathic etiologies were preponderant in infants, metabolic and sarcomeric diseases were most frequent in the childhood-onset group. Major adverse cardiac events (MACE) occurred in 31.8% of patients, including hospitalization for acute heart failure in 25.5% of patients, most commonly due to DCM. Overall, the most severe outcomes were documented in patients with metabolic diseases.

CONCLUSIONS

In a consecutive cohort of pediatric patients with CMP, those with infantile onset and with a metabolic etiology had the worst prognosis. Overall, MACE occurred in 41% of the entire population, most commonly associated with DCM, inborn errors of metabolism and genetic syndromes. Systematic NGS genetic testing was critical for etiological diagnosis and management.

Treatment discontinuation following low-dose TKIs in 248 chronic myeloid leukemia patients: Updated results from a campus CML real-life study

TKIs long-term treatment in CML may lead to persistent adverse events (AEs) that can promote relevant morbidity and mortality. Consequently, TKIs dose reduction is often used to prevent AEs. However, data on its impact on successful treatment-free remission (TFR) are quite scarce. We conducted a retrospective study on the outcome of CML subjects who discontinued low-dose TKIs from 54 Italian hematology centers participating in the Campus CML network. Overall, 1.785 of 5.108 (35.0%) regularly followed CML patients were treated with low-dose TKIs, more frequently due to relevant comorbidities or AEs (1.288, 72.2%). TFR was attempted in 248 (13.9%) subjects, all but three while in deep molecular response (DMR). After a median follow-up of 24.9 months, 172 (69.4%) patients were still in TFR. TFR outcome was not influenced by gender, Sokal/ELTS risk scores, prior interferon, number and last type of TKI used prior to treatment cessation, DMR degree, reason for dose reduction or median TKIs duration. Conversely, TFR probability was significantly better in the absence of resistance to any prior TKI. In addition, patients with a longer DMR duration before TKI discontinuation (i.e., >6.8 years) and those with an e14a2 BCR::ABL1 transcript type showed a trend towards prolonged TFR. It should also be emphasized that only 30.6% of our cases suffered from molecular relapse, less than reported during full-dose TKI treatment. The use of low-dose TKIs does not appear to affect the likelihood of achieving a DMR and thus trying a treatment withdrawal, but might even promote the TFR rate.

Salarin C inhibits the maintenance of chronic myeloid leukemia progenitor cells

We previously showed that incubation of chronic myeloid leukemia (CML) cells in very low oxygen selects a cell subset where the oncogenetic BCR/Abl protein is suppressed and which is thereby refractory to tyrosine kinase inhibitors used for CML therapy. In this study, salarin C, an anticancer macrolide extracted from the Fascaplysinopsis sponge, was tested as for its activity on CML cells, especially after their incubation in atmosphere at 0.1% oxygen. Salarin C induced mitotic cycle arrest, apoptosis and DNA damage. Salarin C also concentration-dependently inhibited the maintenance of stem cell potential in cultures in low oxygen of either CML cell lines or primary cells. Surprisingly, the drug also concentration-dependently enforced the maintenance of BCR/Abl signaling in low oxygen, an effect which was paralleled by the rescue of sensitivity of stem cell potential to IM. These results suggest a potential use of salarin C for the suppression of CML cells refractory to tyrosine kinase inhibitors.

Human Preosteoblastic Cell Culture from a Patient with Severe Tumoral Calcinosis-Hyperphosphatemia Due to a New GALNT3 Gene Mutation: Study of In Vitro Mineralization

Human disorders of phosphate (Pi) handling and skeletal mineralization represent a group of rare bone diseases. One of these disease is tumoral calcinosis (TC). In this study, we present the case of a patient with TC with a new GALNT3 gene mutation. We also performed functional studies using an in vitro cellular model. Genomic DNA was extracted from peripheral blood collected from a teenage Caucasian girl affected by TC, and from her parents. A higher capability to form mineralization nodules in vitro was found in human preosteoblastic cells of mutant when compared to wild-type controls. We found a novel homozygous inactivating splice site mutation in intron I (c.516-2a>g). A higher capability to form mineralization nodules in vitro was found in the mutant cells in human preosteoblastic cells when compared to wild-type controls. Understanding the functional significance and molecular physiology of this novel mutation will help to define the role of FGF23 in the control of Pi homeostasis in normal and in pathological conditions.

Differences among young adults, adults and elderly chronic myeloid leukemia patients

BACKGROUND

The incidence of chronic myeloid leukemia (CML) increases with age, but it is unclear how the characteristics of the disease vary with age. In children, where CML is very rare, it presents with more aggressive features, including huge splenomegaly, higher cell count and higher blast cell percentage.

PATIENTS AND METHODS

To investigate if after childhood the disease maintains or loses these characteristics of aggressiveness, we analyzed 2784 adult patients, at least 18 years old, registered by GIMEMA CML WP over a 40-year period.

RESULTS

Young adults (YAs: 18-29 years old) significantly differed from adults (30-59 years old) and elderly patients (at least 60 years old) particularly for the frequency of splenomegaly (71%, 63% and 55%, P < 0.001), and the greater spleen size (median value: 4.5, 3.0 and 1.0 cm, P < 0.001). According to the EUTOS score, that is age-independent, high-risk patients were more frequent among YAs, than among adult and elderly patients (18%, 9% and 6%, P < 0.001). In tyrosine kinase inhibitors-treated patients, the rates of complete cytogenetic and major molecular response were lower in YAs, and the probability of transformation was higher (16%, 5% and 7%, P = 0.011).

CONCLUSIONS

The characteristics of CML or the host response to leukemia differ with age. The knowledge of these differences and of their causes may help to refine the treatment and to improve the outcome.

CLINICAL TRIAL NUMBERS

NCT00510926, NCT00514488, NCT00769327, NCT00481052.

A novel recessive mutation of fibroblast growth factor-23 in tumoral calcinosis

BACKGROUND

Tumoral calcinosis is a rare disease characterized by hyperphosphatemia due to hypophosphaturia and by ectopic calcifications. Phosphatonins are important hormones that regulate phosphorus homeostasis. Tumoral calcinosis is a rare congenital disorder in which the differential diagnosis from other syndromes associated with extraskeletal calcifications may be difficult. Mutations in the UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase-3 (GALNT3) and fibroblast growth factor-23 (FGF23) genes have been described. Mutational analysis is important for the early recognition of the disorder, for prevention of its complications, and for family screening strategies. We examined two unrelated white patients affected by tumoral calcinosis.

METHODS

The first patient was a woman with a history of an ectopic calcification in the left shoulder. The second patient was a man with a history of an ectopic calcification in the right buttock. Routine biochemistry and FGF-23 assays were performed on serum samples. Genomic DNA was extracted from peripheral blood. The FGF23 and GALNT3 genes were analyzed by direct sequencing.

RESULTS

A new homozygous H41Q codon 41, C-->A transversion at position 123 (c.123C>A) in exon 1 of the FGF23 gene was evidenced in both patients. No mutation of the GALNT3 gene was detected in these patients. As determined by an ELISA assay, intact FGF-23 circulating protein was low in both patients.

CONCLUSIONS

This is the fourth mutation of the FGF23 gene described in subjects with tumoral calcinosis.

Selective anti-leukaemic activity of low-dose histone deacetylase inhibitor ITF2357 on AML1/ETO-positive cells

We analysed the in vitro effects of a new hydroxamate derivative, ITF2357, on AML cells. ITF2357 potently induced histone acetylation. ITF2357 0.1 microM blocked proliferation and induced apoptosis in AML1/ETO-positive Kasumi-1 cells, while AML1/ETO-negative HL60, THP1 and NB4 cell lines were sensitive only to 1 microM ITF2357. Apoptosis was induced by 0.1 microM ITF2357 in AML1/ETO-positive primary blasts and U937-A/E cells induced to express AML1/ETO, but not in U937-A/E cells non-expressing AML1/ETO. In Kasumi-1 cells 0.1 microM ITF2357 induced AML1/ETO degradation through a caspase-dependent mechanism. ITF2357 0.1 microM also determined DNMT1 efflux from, and p300 influx to, the nucleus. Moreover, 0.1 microM ITF2357 determined local H4 acetylation and release of DNMT1, HDAC1 and AML1/ETO, paralleled by recruitment of p300 to the IL-3 gene promoter. ITF2357 treatment, however, did not induce re-expression of IL-3 gene. Accordingly, the methylation level of IL-3 promoter, as well as of several other genes, was unmodified. In conclusion, ITF2357 emerged as an anti-leukaemic agent very potent on AML cells, and on AML1/ETO-positive cells in particular. More relevantly, clearly emerged from our results that ITF2357 could be an ideal agent to treat AML subtypes presenting AML1/ETO fusion protein which determine HDAC involvement in leukaemogenesis.

Histone deacetylase inhibitors: molecular and biological activity as a premise to clinical application

Epigenetic modifications are reversible chromatin rearrangements that in normal cells modulate gene expression, without changing DNA sequence. Alterations of this equilibrium, mainly affecting the two interdependent mechanisms of DNA methylation and histone acetylation, are frequently involved in the genesis of cancer. The histone code, regulating gene expression, is constituted by the combination of different acetylated lysine residues of histones. In neoplastic cells, the abundance of deacetylated histones is usually associated with DNA hypermethylation and gene silencing. Several compounds, known to have in vitro antineoplastic activity, have been eventually shown to act as histone deacetylase inhibitors. Thus, HDAC inhibitors have been successfully introduced in clinical trials as antitumour agents. They are classified according to their chemical structures and are endowed with different specificity and affinity for the HDACs of classes 1, 2, 4. Among HDAC inhibitors, the most potent are the hydroxamic acid derivatives, like SAHA, which has been recently approved for therapy of cutaneous T-cell lymphomas. Other classes of HDAC inhibitors are short chain fatty acids (SCFA), benzamides, epoxyketone and non-epoxyketone containing cyclic tetrapeptides, and hybrid molecules. SCFA, although widely used (especially valproic acid) and clinically efficacious, have weak HDAC inhibition constants. Benzamides, like MS-275, and cyclic peptides, like depsipeptide, have been studied in numerous clinical trials and demonstrated low toxicity and activity in solid and haematological neoplasms. HDAC inhibitors are also potent radiation sensitizers. Their future in oncology may thus be based on their activity as single agents and on their synergy with the hypomethylating drugs and with chemo- and radiotherapeutics.

Relationship of volumetric bone mineral density and structural parameters with ERalpha gene polymorphisms

Bone mineral density (BMD) contributes to bone strength, and methods for clinical assessment of bone quality characteristics beyond what can be gathered by BMD are awaited. Peripheral quantitative computed tomography (pQCT) allows for separate assessments of cortical and trabecular bone, providing information on bone geometry. Previous studies examining the relationship between estrogen receptor alpha (ERalpha) gene polymorphisms and BMD have been performed in large populations. However, only limited information is available on the possible segregation of ERalpha gene polymorphisms with bone structural properties. The aim of our study was to evaluate the association of XbaI and PvuII ERalpha gene polymorphisms with QCT parameters. We studied 900 subjects (541 women, 449 men) participating to the InCHIANTI study. By tibial pQCT we evaluated trabecular volumetric BMD, cortical volumetric BMD, cortical bone area, and cortical thickness (CtTh). Subjects were genotyped for ERalpha gene PvuII and XbaI polymorphisms. Analysis of variance was used for statistical analysis. Male subjects with PP and XX genotypes had higher geometric parameters, and female subjects with XX and PP genotypes showed higher densitometric parameters than other genotypes; however, the differences did not reach statistical significance. After adjustment for potential confounders, we found a significant (P = 0.002) CtTh difference across PvuII polymorphism in male subjects, with higher CtTh values in PP genotypes with respect to Pp and pp genotypes. These results show a relationship between the presence of the P allele and higher values of CtTh in male subjects, indicating for ERalpha a role in the control of tibial bone geometry.

FokI polymorphism of the vitamin D receptor gene correlates with parameters of bone mass and turnover in a female population of the Italian island of Lampedusa

One of the most promising genetic approaches to dissecting a multifactorial disease is represented by genetically isolated population studies. We studied a genetic marker in a cohort of women living on the Mediterranean island of Lampedusa, a geographically isolated population. Lampedusa, located between the African coast and Sicily, consists of a young genetic isolate (<20 generations) with an exponential growth in the last generations. We analyzed the association between the FokI vitamin D receptor (VDR) gene polymorphism, previously proposed as a predictor of bone mass, with parameters of bone mass and turnover in a cohort of pre- and postmenopausal women living on Lampedusa. In 424 women (277 postmenopausal and 147 premenopausal), allelic frequencies were 49% for the F allele and 51% for the f allele. Using analysis of covariance, we found that subjects with ff genotype exhibited a significantly (P < 0.001) lower lumbar spine bone mass, by dual-energy X-ray absorptiometry, and lower values of bone ultrasonographic parameters (speed of sound and broadband ultrasound attenuation) relative to those with Ff and FF genotypes. Conversely, osteocalcin and serum cross-laps were significantly higher in ff and Ff compared to FF genotype. Our data suggest that FokI VDR polymorphism may contribute to the determination of bone mass and turnover in both pre- and postmenopausal women in this geographically isolated population.

A comparison of methods for the analysis of low abundance proteins in desmoid tumor cells

The desmoids are a group of rare clinically diverse, deep-seated fibrous neoplasms. The exact etiology is unknown, but several factors are considered to be positively correlated with their development and growth, i.e., genetic and hormonal factors and trauma. These tumors may be sporadic or associated with a genetic disease such as familial adenomatous polyposis (FAP). Devoid of metastatic potential, they tend to form large, infiltrative masses which, if not completely excised, recur repeatedly. Although surgery is widely accepted as the first-line treatment for extra-abdominal and abdominal wall desmoids, a proportion of cases are successfully palliated with either estrogen antagonists (tamoxifen, toremifene, and raloxifene) or nonsteroidal anti-inflammatory drugs. We describe and compare four methods for evaluating the expression of estrogen receptors alpha/beta and COX-1 and COX-2 in desmoid tumor-derived cells and tissues: immunocytochemistry, immunohistochemistry, RT-PCR, and two-color Western blot detection with the Odyssey infrared imaging system. Through this comparative analysis, Western blot with Odyssey was recognized as the best method to analyze the expression particularly of low expressed proteins in desmoid-derived cells. The use of a specific and reliable assessment method becomes fundamental in the evaluation of the presence and modulation of proteins which are important but weakly expressed in these rare tumors.

Characterization of the functional and growth properties of long-term cell cultures established from a human somatostatinoma

In somatostatinoma, a rare malignant somatostatin (SST)-secreting neoplasia, tumour regression is rarely observed, implying the need for novel antiproliferative strategies. Here, we characterized a long-term culture (SST-secreting cancer (SS-C cells)) established from a human somatostatinoma. High concentrations of SST and chromogranin A were released by SS-C cells and SST release was stimulated by depolarizing stimuli and inhibited by the SST analogue, octreotide. SS-C cells expressed mRNA for SST receptor (SSTR) subtypes 1, 2 and 4, being also able to bind native SST. Moreover, SS-C cells were positively stained with an antibody to SSTR2. SS-C cells also expressed interferon-gamma (IFN-gamma) receptor mRNA and measurable telomerase activity. Our findings indicate that in vitro exposure of SS-C cells to native SST-28, to octreotide, to IFN-gamma, or to 3'-azido-3'deoxythymidine (AZT), a telomerase inhibitor, results in inhibition of SS-C cell proliferation. Concomitant with growth inhibition, apoptosis was detected in SST-, octreotide-, IFN-gamma- or AZT-treated SS-C cell cultures. Taken together our results characterized native SST, SST analogues, IFN-gamma and a telomerase inhibitor as growth-inhibiting and proapoptotic stimuli in cultured human somatostatinoma cells. Based on these findings, the potential of SST analogues, IFN-gamma and AZT, alone or in combination, should be further explored in the medical treatment of somatostatinoma.

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.

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.

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.

Stability of resveratrol over time and in the various stages of grape transformation

Research has been carried out with the purpose of verifying whether the resveratrol content in the skins or pomace of grapes stored for a long period of time without any particular protection with regard to temperature and humidity, could lead to a reduction of the content of this product detected at the beginning of the processing of grapes in vinification procedures. The dosages carried out both on the grape skin and on the pomace taken after fermentation and stored for a certain period of time, as well as on the products derived from alcoholic distillation, did not show the expected alterations in resveratrol content, considering their storage in bad environmental conditions for a long period of time. The results obtained confirm that resveratrol, unlike anthocyanins and other polyphenols, is stable and stores well over time.

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.

Plasma and tissue resveratrol concentrations and pharmacological activity

In this study a comparison was made between results obtained from resveratrol dosages which have been shown to be pharmacologically active, in vitro and in vivo, and the results of plasma and tissue concentrations obtained after a single administration or after prolonged administration of red wine with a known resveratrol content. The dosages used by different investigators in the tests are very different and, in general, rather high in relation to the concentrations which are found in wine or grapes. The results of our tests on platelet aggregation confirm that even with modest dosages of resveratrol, a pharmacological effect can be observed, and that these dosages can be compatible with the resveratrol concentrations obtained after oral administration. The data obtained from these tests on animals can lead to the conclusion that even an average drinker of wine can, particularly in the long term, absorb a sufficient quantity of resveratrol to explain the beneficial effect of red wine on health, which has been observed in epidemiological studies carried out in populations whose daily diet includes the drinking of wine.

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.

Apoptotic and antiproliferative effects of gemcitabine and gemcitabine plus Ara-C on blast cells from patients with blast crisis chronic myeloproliferative disorders

BACKGROUND

Blast phase of chronic myeloid leukemia (CML) as well as the rare acute transformation of other chronic myeloproliferative disorders constitute forms of leukemia that are particularly refractory, even to aggressive chemotherapy. Many attempts have thus been made to identify new drugs that could be active in these diseases. We wanted to evaluate whether gemcitabine (dFdC), a pyrimidine analogue widely employed in lung cancer chemotherapy, was able to block in vitro proliferation of bcr/abl-positive and bcr/abl-negative blast cells in primary culture. We already showed that gemcitabine is active in inhibiting proliferation and inducing apoptosis of HL60 cells.

METHODS

We studied the influence of dFdC on the proliferative potential of blasts by means of tritiated thymidine uptake, colony formation in semisolid medium and cell cycle parameters at flow cytometry. The efficacy of dFdC in inducing apoptosis was evaluated by flow cytometry (A0 peak) and by DNA agarose gel electrophoresis.

RESULTS

We demonstrated that dFdC already inhibits tritiated thymidine uptake at doses of 10 microM after 72 hours of culture, and that this effect is dose dependent. The addition of Ara-C 5 microM in the culture medium of dFdC provoked a synergistic inhibitory effect. Consistent results were obtained when cell cycle distribution was studied. In fact, cell incubation in the presence of dFdC resulted in a significant decrease of cells in S phase, although with a certain heterogeneity among cases. The antileukemic activity of dFdC appeared to be specific since it was mediated through apoptosis. We could demonstrate the appearance of the pre-G1 apoptotic peak at cytofluorimetric analysis, and the characteristic DNA fragmentation pattern at agarose electrophoresis in all 10 cases after treatment with different doses of dFdC. Induction of apoptosis was maximal for the highest doses of dFdC (100 mM) and for the combination of dFdC and Ara-C.

INTERPRETATION AND CONCLUSIONS

Following incubation with Gemcitabine leukemic blasts from chronic myeloproliferative disorders are induced to accumulate intracytoplasmatic and nuclear Ara-C and undergo apoptosis. These observations suggest that gemcitabine could be considered a candidate drug, capable of being used in polychemotherapy of refractory acute phase chronic myeloproliferative disorders.