PubMed Health⌕ Search

Biomedical subjects

G Scambia

Publications and source records attributed to G Scambia.

At least 127 records · Page 7Linked to original sources
PubMed1999

Tamoxifen induces oxidative stress and apoptosis in oestrogen receptor-negative human cancer cell lines.

Recent data have demonstrated that the anti-oestrogen tamoxifen (TAM) is able to facilitate apoptosis in cancer cells not expressing oestrogen receptor (ER). In an attempt to identify the biochemical pathway for this phenomenon, we investigated the role of TAM as an oxidative stress agent. In two ER-negative human cancer cell lines, namely T-leukaemic Jurkat and ovarian A2780 cancer cells, we have demonstrated that TAM is able to generate oxidative stress, thereby causing thiol depletion and activation of the transcriptional factor NF-kappaB. As described for other oxidative agents, TAM was able to induce either cell proliferation or apoptosis depending on the dose. When used at the lowest dose tested (0.1 microM), a slight proliferative effect of TAM was noticed in terms of cell counts and DNA synthesis rate, whereas at higher doses (10 microM) a consistent occurrence of apoptosis was detected. Importantly, the induction of apoptosis by TAM is not linked to down-regulation or functional inactivation by phosphorylation of the antiapoptotic bcl-2 protein.

Antineoplastic Agents, Hormonal↗
PubMed1999

hMSH2 and GTBP expression in advanced stage epithelial ovarian cancer.

Defects in DNA mismatch repair have been associated with both hereditary and sporadic forms of human cancer. Most of the attention has been focused on the incidence and genetics of mismatch repair defects, while little is known about the expression levels of the mismatch repair proteins and their significance in cancer cell biology. In this study, both the expression levels of hMSH2 and GTBP proteins were investigated by Western blotting in 20 untreated epithelial ovarian cancers. For these analyses, a commercial anti-hMSH2 monoclonal antibody and a newly generated mouse monoclonal anti-GTBP antibody were used. hMSH2 and GTBP proteins were detected by Western blotting in 19 out of 20 (95%) samples analysed and were found to be directly correlated (r= +0.51, P = 0.025). hMSH2 expression was significantly higher in ovarian cancer cells originating from solid tumours than from ascites (H = 4.5, P = 0.033), whereas GTBP content did not significantly differ according to the origin of cancer cells. No statistically significant differences were found in the distribution of hMSH2 and GTBP levels according to the age of the patients, grade of differentiation, histotype and extent of surgical debulking. The amount of hMSH2 protein was demonstrated to be significantly lower in stage IV than in stage III patients (H = 7.35, P = 0.007). Moreover, significantly lower hMSH2 levels were observed in non-responding patients compared to patients who achieved complete or partial response to cisplatin-based chemotherapy (H = 4.88, P = 0.027). Conversely, GTBP levels were not distributed differently according to stage of disease and chemotherapy response. Our study suggests a possible involvement of hMSH2 in ovarian cancer cell biology and susceptibility to chemotherapy. The possible biological and/or clinical role of GTBP expression in ovarian cancer patients remains to be elucidated.

Adult↗
PubMed1999

p53 overexpression is associated with cytoreduction and response to chemotherapy in ovarian cancer.

The aim of this study was to assess the association of p53 status with primary cytoreduction, response to chemotherapy and outcome in stage III-IV primary ovarian cancer patients. Immunohistochemical analysis of p53 was performed on formalin-fixed, paraffin-embedded specimens from 168 primary ovarian carcinomas by using the DO-7 monoclonal antibody. p53 nuclear positivity was found in 84 out of 162 (52%) malignant tumours. A higher percentage of p53 nuclear positivity was observed in patients with advanced stage of disease than in stage I-II (57% vs 23% respectively; P = 0.0022) and in poorly differentiated versus well/moderately differentiated tumours (59% vs 32% respectively; P = 0.0038). The multivariate analysis aimed to investigate the association of FIGO stage, grade and p53 status with primary cytoreduction in 136 stage III-IV patients showed that stage IV disease may influence the possibility to perform primary cytoreduction in ovarian cancer patients. p53-positivity also maintained a trend to be associated with poor chance of cytoreduction. In patients who underwent pathologic assessment of response, cases who did not respond to chemotherapy were much more frequently p53-positive than p53-negative (86% vs 14% respectively; P = 0.012). Moreover, patients with stage III disease and < 2-cm residual tumour were more likely to respond to treatment. In multivariate analysis, FIGO stage and p53 expression were independently correlated with pathologic response to chemotherapy. Time to progression and survival rates were shown not to be different in p53-positive versus p53-negative patients.

Adult↗
PubMed1999

IL-6, M-CSF and IAP cytokines in ovarian cancer: simultaneous assessment of serum levels.

The aim of this study was to simultaneously determine IL-6, M-CSF and IAP levels in 61 serum samples of previously untreated ovarian cancer patients. A direct correlation between IL-6 and M-CSF has been found in our patient population (r = +0.41, p = 0.013), while IAP serum levels failed to correlate with M-CSF (r = +0.15, p = 0. 24) and IL-6 (r = +0.17, p = 0.18) levels. Since IL-6 and M-CSF have been demonstrated to be both induced in response to the same agents, it is conceivable that a mechanism of coregulation in the production of these cytokines by tumor cells and macrophages might occur. The direct correlation between IL-6 and M-CSF also suggests that tumor-derived cytokines can potentially lead to a self-maintaining cytokine network by recruiting cytokine-producing host cells and by perpetuating cytokine production.

Biomarkers, Tumor↗
PubMed1999

Erythropoietin addition to granulocyte colony-stimulating factor abrogates life-threatening neutropenia and increases peripheral-blood progenitor-cell mobilization after epirubicin, paclitaxel, and cisplatin combination chemotherapy: results of a randomized comparison.

PURPOSE AND METHODS: The ability of granulocyte colony-stimulating factor (G-CSF) plus erythropoietin (EPO) treatment was compared in a randomized fashion with that of G-CSF treatment alone in promoting hematologic recovery and peripheral-blood progenitor-cell (PBPC) mobilization in previously untreated patients with advanced ovarian cancer who underwent their first course of epirubicin, paclitaxel, and cisplatin (ETP) chemotherapy during a phase II study of intensive outpatient ETP chemotherapy followed by high-dose carboplatin, etoposide, and melphalan (CEM) late intensification with PBPC support. RESULTS: Comparative analysis of hematologic recovery of 50 randomized patients, after ETP chemotherapy, showed that life-threatening neutropenia occurred in 88% of the patients treated with G-CSF alone, whereas it occurred in only 4% of patients treated with G-CSF + EPO. Significantly different WBC and polymorphonuclear leukocyte (PMN) counts were observed in the two distinct arms on the day of WBC nadir (P <.0001 and P <.0001, respectively). Moreover, the addition of EPO to G-CSF increased PBPC mobilization and collection as compared with that in G-CSF-treated patients (P =.0009 and P =.0026, respectively), who required a significantly higher number of leukaphereses than G-CSF + EPO-treated patients (P =.0076) to obtain the planned minimum dose of PBPCs. Qualitative analysis by cloning assay of PBPCs collected in both arms revealed that G-CSF- and G-CSF + EPO-mobilized PBPCs have comparable in vitro functional properties. CONCLUSION: This randomized comparison revealed that EPO significantly increases most of the hematologic effect produced by G-CSF administration after chemotherapy. This biologic property of EPO translated in vivo into a global improvement of patients' hematologic status.

Adult↗
PubMed1999

Large volume leukapheresis for collecting hemopoietic progenitors: role of CD 34+ precount in predicting successful collection.

In this work we evaluated the efficacy of stem cell collection with Large Volume Procedures. (LVP), and analysed the importance of the CD34+ cell precount in promoting the collection of a sufficient number of CD34+ cells for transplantation, using the Univariate Logistic Regression analysis. Eighty-nine leukapheresis were performed in 49 patients with hematological malignancies and solid tumors, mobilized with chemotherapy plus Granulocyte Colony Stimulating Factor (G-CSF). For each procedure 15.8 liters of blood were processed. The median value of Nucleated Cells (NC) and CD34+ cells precount was respectively 8.29 x 10(9)/ml (range 1.13/45.4) and 43.08 x 103/ml (range 1.06/795.2). Results show the capability of LVP to collect large quantities of hemopoietic progenitors with a median CD34+ cell total yield of 215.02 x 10(6) (range 5.03/2210). The yields per patients' body weight were: CD34+ cells 3.23 x 10(6)/kg (range 0.081/41.58). The regression analysis between blood cell precounts and collection yields gave the following correlations: the CD34+ cell precount correlates with CD34+ yield (r = 0.78 p < 0.00) and with CD34+ cell yield/kg (r = 0.76 p < 0.00). The number of CD34+ cells processed correlated with the number of CD34+ cells collected/kg (r = 0.83 p < 0.000). To investigate the importance of CD 34+ cell precount in promoting CD34+ cell yields > or =2.5 x 10(6)/kg we performed a Univariate Logistic Regression analysis that showed in our patients a probability of collecting > or =2.5 x 10(6) CD34+/kg that rose from 0.6 to 0.95 for CD 34+ precounts that oscillated from 30 to 40 x 10(3) CD34+ cells/ml, respectively. The Univariate Logistic Regression gave a probability of collecting > or =2.5 x 10(6) CD34+ cells/kg that oscillated between 0.64/0.98 for values of CD34+ cells processed from 6 x 10(6)/kg to 8 x 10(6)/kg, p < 0.000. Sixty-three percent of patients reached the target dose of 2.5 x 10(6) CD34+ cells/kg with only one LVP. Until now 12 patients have been transplanted and all have had a prompt and complete lasting recovery. These results confirm the efficacy of LVP in harvesting hemopoietic progenitors and their ability in reconstituting hemopoiesis of transplanted patients, enabling the estimation of CD34+ precounts and CD34+ cells processed values, highly predictive for the collection of > or =2.5 x 10(6) CD34+ cells/kg. Furthermore, the Logistic Model suggests that the best strategy to plan a successful CD34+ cell collection procedure is to identify for each patient the amount of CD34+ cells/kg to be processed rather than the fixed processing of 3/5 blood volumes in all patients.

Adolescent↗
PubMed1999

[A zinc sulfate and usnic acid preparation used as post-surgical adjuvant therapy in genital lesions by Human Papillomavirus].

BACKGROUND: To evaluate the efficacy and safety of intravaginal administration of a zinc sulphate and usnic acid compound as adjuvant therapy of Human Papillomavirus (HPV) genital infection, after radiosurgical treatment (RS). METHODS: One hundred patients affected by HPV genital infection were enrolled in the study from October 1996 to July 1998. Patients were classified according to colposcopic and cytologic criteria and treated with RS. Patients were randomized into three groups: the first group did not follow any therapy after RS (control group), (n = 50); the second group was pharmacologically treated with intravaginal administration of a usnic acid and zinc sulphate compound (Zeta N, Bergamon Italia) before and after RS (n = 25), the third group was pharmacologically treated only after RS (n = 25). The last two groups were considered together for the statistical analysis. Patients were reevaluated after one, two, three and six months from electrocoagulation. The safety of treatment was also investigated. RESULTS: One month after RS. HPV lesions disappeared in 93% of the patients in the control group and in 100% of patients treated with usnic acid and zinc sulphate. After one month, reepithelization was complete in 65% of cases treated with usnic acid and zinc sulphate and in only 28% of the control group (p = 0.001). Two months later reepithelization was 94% in the patients pharmacologically treated compared to 76% of the control group (p = 0.06). Treatment prior to RS resulted in a reduction of the overall area of lesions in 88% of cases. Three months after RS, there was a significant reduction of recurrence in the group treated with usnic acid and zinc sulphate (p = 0.01). This reduction was still significant at six months (p = 0.005). CONCLUSIONS: Usnic acid and zinc sulphate adjuvant treatment improved time of reepithelization and reduce the recurrence with few side effects and a good compliance.

Adult↗
PubMed1999

Biological evaluation on different human cancer cell lines of novel colchicine analogs.

Three new 7-0-substituted deacetamidothiocolchicine derivatives have been evaluated for their antitumor activity against various human tumor cell lines, some of which express the multidrug resistance (MDR) phenotype, for their impact on the cell cycle and their binding to tubulin. Colchicine and thiocolchicine were used as reference compounds. Thiocolchicine was the most active agent on MDR-negative cells in terms of growth inhibition, whereas for multidrug-resistant cells, thiocolchicone was the most active compound (IC50 = 14 nM). As indicated by statistical analysis, a perfect agreement for the potency order (IC50 values) of the compounds between all the MDR-negative cancer cells (k = 1.00), a poor agreement between MDR-positive and MDR-negative cancer lines, and a moderate agreement (k = 0.50) between the two resistant cancer cells MCF-7 ADRr and CEM VBL were observed. To gain further insight into the mechanism of the antitumor activity of colchicinoids, the most active compounds, colchicone and thiocolchicone, were selected to evaluate their effect on cell cycle, apoptosis, and tubulin interaction. The highest recruitment activity into the G21/M phase of the cell cycle was detected in thiocolchicone-treated breast cancer cells. Interestingly, after 72 h of culture, when the cell cycle block subsided, a consistent amount of DNA fragmentation, a hallmark of apoptosis, was evident. Morphological analysis of MCF-7 ADRr cells confirmed this hypothesis and revealed that thiocolchicone was able to induce apoptosis in this MDR-bearing model. We also demonstrated, using flow cytometry, that thiocolchicone interacts with alpha- and beta-tubulin, thereby affecting the expression of both subunits.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Cytotoxic effects toward human hematopoietic progenitor cells and tumor cell lines of paclitaxel, docetaxel, and newly developed analogues IDN5109, IDN5111, and IDN5127.

The growth inhibitory effect of paclitaxel, docetaxel, and newly developed taxanes IDN5109, IDN5111, and IDN5127 was assessed on peripheral blood (PB) CD34+ maintained in liquid culture and on three human cancer cell lines (MDA-MB231, MCF-7 ADRr, CEM VBLr). Concomitantly, DNA analysis was also performed. For unfractionated peripheral blood progenitor cells (PBPC) toxicity was also assessed by clonogenic assay. The cytotoxic effects induced by taxanes toward PBPC as measured by clonogenic assay were correlated with those found for multidrug resistance (MDR)-positive cell lines (IDN5109 > IDN5111 > IDN5127 > docetaxel > paclitaxel). We established a therapeutic index (TI) between the antitumor activity in MDR-positive cells and the toxicity toward PBPC. Paclitaxel and IDN5109, as determined by TI, showed the best value in MDR-negative and MDR-positive cells, respectively. The ranking of the cytotoxic effects observed in PB CD34+ was not correlated with that obtained in clonogenic assay and in cancer cells (IDN5127 > IDN5109 > docetaxel > IDN5111). Remarkably, in DNA analysis docetaxel induced the maximal cell cycle blocking activity. Newly developed taxanes IDN5109 and IDN5111 are endowed of a profile of anticancer activity in MDR-bearing cells and toxicity toward hematopoietic progenitors better than that of docetaxel. However, mechanism(s) underlying toxicity toward hematopoietic progenitors could be, at least in part, different from that of docetaxel and likely dependent on the interaction with P-glycoprotein function in PB CD34+ cells.

Antigens, CD34↗
PubMed1998

Growth-inhibitory effect of tamoxifen and quercetin and presence of type II estrogen binding sites in human laryngeal cancer cell lines and primary laryngeal tumors.

Quercetin and tamoxifen, in a range of concentrations between 0.01 and 5 microM, exert a dose-dependent inhibition on the anchorage-dependent and anchorage-independent cell growth of Hep2 and CO-K3 laryngeal cancer cell lines. Cell cycle analysis revealed that the growth-inhibitory effect was associated with a block of the cells at the G2/M checkpoint of the cell cycle followed by DNA fragmentation. This suggests that the failure of cells to proceed through the G2/M checkpoint can be a trigger for apoptosis. The induction of apoptosis by quercetin and tamoxifen was confirmed immunocytochemically by the in situ nick end labeling (TUNEL) reaction. These compounds also exerted a dose-dependent growth-inhibitory effect on primary tumor cells, as assessed by colony-forming assay and bromodeoxyuridine labeling. Laryngeal cancer cell lines and primary tumor cells expressed Type II estrogen binding sites (Type II EBS) with binding characteristics similar to those of Type II EBS in other tumor cells. Since the affinities of quercetin and tamoxifen for Type II EBS were correlated with their growth-inhibitory potential while ipriflavone neither interacted with these sites nor inhibited cell growth, the possibility exists that the action of these compounds is mediated, at least in part, by the interaction with Type II EBS. In conclusion, our data indicate that quercetin and tamoxifen could be potentially useful in laryngeal cancer treatment.

Apoptosis↗
PubMed1998

Comparative study on the induction of cytostasis and apoptosis by ICI 182,780 and tamoxifen in an estrogen receptor-negative ovarian cancer cell line.

We have compared the effects of a broad range of clinically relevant concentrations (0.1 to 10 microM) of the steroidal pure anti-estrogen ICI 182,780 and the non-steroidal partial anti-estrogen tamoxifen (TAM) on cell proliferation and induction of apoptosis in the estrogen receptor (ER)-negative ovarian carcinoma cell line A2780. Cell proliferation was assessed by evaluating the number of viable cells, changes in cell-cycle distribution and cell replication rate; while apoptosis induction was assessed by examining nuclear morphological changes associated with apoptotic death and DNA cleavage into 300 and 50 kbp units (large DNA fragmentation) and into 180 bp units (internucleosomal DNA fragmentation). We provide evidence that 0.1 to 10 microM ICI 182,780 and TAM significantly inhibit the growth of A2780 cells in a dose-dependent fashion. Cytokinetic analysis revealed that only 10 microM TAM caused a significant blockade in G1 and a diminished replication rate. Conversely, we show that 0.1 to 10 microM ICI 182,780 and TAM induce apoptosis in a dose-dependent fashion. The earliest recognizable apoptotic change induced by treating the cells with these 2 drugs was DNA cleavage into 300 and 50 kbp units. This started to be visible in adherent cells, implying that apoptosis induction by ICI 182,780 and TAM was not determined by the loss of cell-substrate interaction. A further degradation of 300 and 50 kbp DNA fragments occurred in cells that had lost their adhesion to the culture plate. We observed the ladder pattern typical of internucleosomal DNA cleavage by treating A2780 cells with the highest dose (10 microM) of ICI 182,780 and TAM. Lower concentrations of these 2 drugs (0.1 to 1 microM) did not produce such a pattern of DNA fragmentation. Typical features of apoptotic nuclei were detectable after both drug treatments. However, cells undergoing apoptosis induced by ICI 182,780 showed hyper-aggregation of chromatin, whereas TAM-treated cells preferentially exhibited chromatin clumping.

Antineoplastic Agents↗
PubMed1998

Epidermal growth factor receptor (EGFR) is not related to the prognosis of cervical cancer.

We analyzed the prognostic significance of epidermal growth factor receptor (EGFR) in a large prospective series of 90 cervical cancer patients observed for a long follow-up period. EGFR levels ranged from 0 to 52.1 fmol/mg protein, with a median value of 6.0 fmol/mg protein. Patients with an advanced stage of disease expressed lower EGFR levels than those with an early stage of disease (median values were 7.8 fmol/mg protein for patients with stage I-II and 4.2 fmol/mg protein for patients with stage III-IV, P = 0.013). There was no correlation between EGFR expression and other clinicopathological parameters analyzed. No significant relationship was shown between EGFR positivity and overall survival. No significant relationship between EGFR status and disease-free survival was observed. Cox univariate regression analysis using EGFR as a continuous variable showed that EGFR levels are not associated with the risk of disease recurrence after treatment or death (P-value not significant). Our data didn't seem to indicate a prognostic role of EGFR in cervical cancer.

Adult↗
PubMed1998

Analysis of cyclin E and CDK2 in ovarian cancer: gene amplification and RNA overexpression.

Cyclins and their associated kinases (cdks) play a key role in controlling the cell cycle, a process whose disregulation can potentially lead to uncontrolled cell growth and hence to cancer. We have studied the role of both cyclin E and its associated kinase cdk2 in ovarian cancer. Primary, metastatic, recurrent and benign ovarian tumors were screened for cyclin E and cdk2 gene amplification. Cyclin E was shown to be amplified in 21% and cdk2 in 6.4% of the cases analyzed. Cyclin E and cdk2 RNA expression levels were determined by semi-quantitative RT-PCR analysis in a partially overlapping series of samples and compared to the expression levels of normal ovarian surface epithelial cells. Cyclin E RNA was overexpressed in 29.5% and cdk2 in 6.5% of ovarian tumors tested. We determined that in most cases gene amplification leads to higher RNA levels for cyclin E and that the overall levels of cyclin E and cdk2 RNA were correlated. We hypothesize that cyclin E and cdk2 are, in part co-regulated and that they may concur to ovarian tumor development.

Adult↗
PubMed1998

Long-term survival following neoadjuvant chemotherapy and radical surgery in locally advanced cervical cancer.

The aim of this study was to analyse the long-term survival and the relationships between prognostic factors at presentation, chemoresponsiveness and disease outcome in patients with locally advanced cervical cancer treated by neoadjuvant chemotherapy and radical surgery (RS). Two consecutive studies of neoadjuvant chemotherapy containing cisplatin, bleomycin plus/minus methotrexate followed by radical hysterectomy and systematic aortic and pelvic lymphadenectomy were carried out between January 1986 and September 1990 on 130 patients with > or = 4 cm stage IB2-III cervical cancer. Survival analysis was performed using the Kaplan and Meier test and Cox's multivariate regression analysis. 128 (98%) of the patients enrolled were evaluable for clinical response and survival, 83% (106) of the patients responded to chemotherapy, with a 15% complete response rate. Logistic regression analysis demonstrated that International Federation of Gynecology and Obstetrics (FIGO) stage, cervical tumour size, parametrial involvement and histotype are highly predictive of response. Responding patients underwent laparotomy, but 8% were not amenable for radical surgery. The 10-year survival estimates were 91%, 80% and 34.5% for stage IB2-IIA bulky, IIB and III, respectively (P < 0.001). After Cox's regression analysis, the parameters significantly associated with survival were the same factors predicting response to neoadjuvant chemotherapy. No stage IB2-IIA bulky patient has so far relapsed, while 12% stage IIB and 56% stage III patients recurred. The 10-year disease-free survival estimates are 91% and 44% for stage IB2-IIB and III, respectively (P < 0.001). Metastatic nodes and persistent tumour in the parametria were the only two independent factors for disease-free survival after multiple regression analysis. After a long-term follow-up (median follow-up 98 months (20-129+)), our results give new evidence of the prognostic value of response to neoadjuvant chemotherapy and of a possible therapeutic benefit of the sequential treatment adopted which, however, must be verified in a randomised setting.

Adult↗
PubMed1998

Prognostic significance of methyl-p-hydroxy-phenyllactate-esterase activity in laryngeal squamous cell carcinoma.

We assayed methyl-p-hydroxyphenyllactate esterase (MeHPLAase) activity in 63 cases of primary laryngeal squamous cell carcinoma. MeHPLAase activity did not show any correlation with oestrogen, progesterone and epidermal growth factor (EGF) receptor levels. No significant relationship was found between MeHPLAase activity and age, sex, tumour site, T classification, stage of disease and EGFR status, whereas a significant inverse relationship was found between enzymatic activity and neck lymph node positivity at presentation. The median value of MeHPLAase activity tended to be higher in tumours with low histopathological grade than in those with high histopathological grade. During the follow-up period (median 50 months, range 2-90 months) locoregional recurrences were observed in 31 out of 63 (49%) cases. At the end of the study, 27 out of 63 (43%) patients had died of cancer. Cox univariate analysis using MeHPLAase activity as a continuous covariate showed that the levels of enzymatic activity were inversely associated with the risk of death and relapse. Assuming the mean value of enzymatic activity as the cut-off value, we found a statistically significant relationship between high MeHPLAase activity and longer relapse-free and overall survival. MeHPLAase activity status retained its prognostic significance also in the lymph node-negative subgroup of patients. On multivariate analysis, both EGFR and MeHPLAase activity proved to be independent factors for predicting a short relapse and the overall survival.

Carboxylic Ester Hydrolases↗
PubMed1998

In vitro effect of amifostine on haematopoietic progenitors exposed to carboplatin and non-alkylating antineoplastic drugs: haematoprotection acts as a drug-specific progenitor rescue.

We evaluated the protective ability of amifostine on peripheral blood mononuclear cell (PBMC)-derived colony-forming unit (CFU) and PB CD34+ cells which were previously exposed in vitro to etoposide, carboplatin, doxorubicin and taxotere. Amifostine pretreatment protected PBMC-derived CFU from the toxic effect of etoposide, carboplatin and taxotere. A significant detrimental effect was exerted by amifostine on the growth of doxorubicin-treated PBMC-derived CFU. Liquid cultures of PB CD34+ cells reproduced faithfully the effects observed on growth of PBMC-derived CFU and confirmed amifostine chemoprotection against etoposide and carboplatin with its detrimental effect on doxorubicin-treated progenitors. Combining the data of viable cell count, cytometric estimation of apoptosis, cell cycle and viable cell replication rate, we found that amifostine protects from etoposide and carboplatin toxicity mainly through a mechanism of cell rescue. Conversely, the detrimental effect of amifostine on the growth of doxorubicin-treated PB CD34+ cells is apparently due to an increased G2/M arrest. In conclusion, amifostine protects haematopoietic progenitors from etoposide, carboplatin and taxotere. Progenitor rescue is the mechanism through which amifostine reduced etoposide and carboplatin toxicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗