Hyper-activation of Aurora kinase a-polo-like kinase 1-FOXM1 axis promotes chronic myeloid leukemia resistance to tyrosine kinase inhibitors.

BACKGROUND: Chronic myeloid leukemia (CML) is a myeloproliferative disease caused by the constitutive tyrosine kinase (TK) activity of the BCR-ABL1 fusion protein. Accordingly, TK inhibitors have drastically changed the disease prognosis. However, persistence of the transformed hematopoiesis even in patients who achieved a complete response to TK inhibitors and the disease relapse upon therapy discontinuation represent a major obstacle to CML cure. METHODS: Thiostrepton, Danusertib and Volasertib were used to investigate the effects of FOXM1, AKA and Plk1 inhibition in K562-S and K562-R cells. Apoptotic cell death was quantified by annexin V/propidium iodide staining and flow cytometry. Quantitative reverse transcription (RT)-PCR was used to assess BCR-ABL1, FOXM1, PLK1 and AURKA expression. Protein expression and activation was assessed by Western Blotting (WB). Clonogenic assay were performed to confirm K562-R resistance to Imatinib and to evaluate cells sensitivity to the different drugs. RESULTS: Here we proved that BCR-ABL1 TK-dependent hyper-activation of Aurora kinase A (AURKA)-Polo-like kinase 1 (PLK1)-FOXM1 axis is associated with the outcome of Imatinib (IM) resistance in an experimental model (K562 cell line) and bone marrow hematopoietic cells. Notably, such a biomolecular trait was detected in the putative leukemic stem cell (LSC) compartment characterized by a CD34+ phenotype. Constitutive phosphorylation of FOXM1 associated with BCR-ABL1 TK lets FOXM1 binding with ß-catenin enables ß-catenin nuclear import and recruitment to T cell factor/lymphoid enhancer-binding factor (TCF/LEF) transcription complex, hence supporting leukemic cell proliferation and survival. Lastly, the inhibition of single components of AURKA-PLK1-FOXM1 axis in response to specific drugs raises the expression of growth factor/DNA damage-inducible gene a (GADD45a), a strong inhibitor of AURKA and, as so, a critical component whose induction may mediate the eradication of leukemic clone. CONCLUSIONS: Our conclusion is that AURKA, PLK1 and FOXM1 inhibition may be considered as a promising therapeutic approach to cure CML.

Modulation of apoptotic signalling by 9-hydroxystearic acid in osteosarcoma cells.

9-hydroxystearic acid (9-HSA) belongs to the class of endogenous lipid peroxidation by-products that greatly diminish in tumors, causing as a consequence the loss of one of the control mechanisms on cell division. We have previously shown that 9-HSA controls cell growth and differentiation by inhibiting histone deacetylase 1 (HDAC1) activity. In this paper our attention has not only been focused on HDAC1 inhibition but also on the hyperacetylation of other substrates such as p53, that is involved in inducing cell cycle arrest and/or apoptosis, and whose activity and stability are known to be regulated by posttranslational modifications, particularly by acetylation at the C-terminus region. 9-HSA administration to U2OS, an osteosarcoma cell line p53 wt, induces a growth arrest of the cells in G2/M and apoptosis via a mitochondrial pathway. In particular hyperacetylation of p53 induced by the HDAC1 inhibitory activity of 9-HSA has been demonstrated to increase Bax synthesis both at the transcriptional and the translational level. The subsequent translocation of Bax to the mitochondria is associated to a significant increase in caspase 9 activity. Our data demonstrate that the effects of 9-HSA on U2OS correlate with posttranslational modifications of p53.

9-Hydroxystearic acid upregulates p21(WAF1) in HT29 cancer cells.

Growing evidence supports the critical role of lipid peroxidation products in the control of cell proliferation. In previous studies we demonstrated the efficient restriction of the proliferation rate in several cell lines resulting from the in vitro treatment with endogenous lipid polar components of cell membranes. Among these, 9-hydroxystearic acid (9-HSA), a primary intermediate of lipid peroxidation, induced a significant arrest in G0/G1 in HT29 colon cancer cells. In response to 9-HSA treatment of HT29 we observed cell growth arrest and increase in p21(WAF1) expression both at the transcriptional and the translational levels. Growth of p21(WAF1)-deleted HCT116 human colon carcinoma cells was not inhibited by 9-HSA. We present evidence that p21(WAF1) is required for 9-HSA mediated growth arrest in human colon carcinoma cells.

Expression of P21(WAF1/CIP1/SID1) cyclin-dependent kinase inhibitor in hematopoietic progenitor cells.

P21(Waf1/Cip1/Sid1) is a critical component of biomolecular pathways leading to the G(1) arrest evoked in response to DNA damage, growth arrest signals and differentiation commitment. It belongs to the Cip/Kip class of cyclin-dependent kinase inhibitors and is at least partly regulated by p53. P21(Waf1/Cip1/Sid1) functional inactivation possibly resulting from mutations of the gene itself or, more likely, from p53 mutations may be critical for either the cell fate following DNA-damaging insults or clonal evolution toward malignancy. In the study presented here we describe a competitive polymerase chain reaction (PCR) strategy whose sensitivity and reproducibility enable us to attain a precise quantitation of p21(Waf1/Cip1/Sid1) expression levels in hematopoietic progenitors, the cell compartment which mostly suffers from the side effects of genotoxic drugs in use for cancer cure. The strategy was set in the M07 factor-dependent hematopoietic progenitor cell line. We confirmed that its p21(waf1/cip1/sid1) constitutive expression level is very low and up-modulated by DNA-damaging agents: ionizing radiations and ultraviolet light. Gene up-modulation resulted in checkpoint activation and, in particular, in a significant G(1) arrest, required for either the repair of damaged DNA sequences or apoptotic cell death. Our competitive PCR strategy was further validated in CD34(+) purified hematopoietic progenitors from healthy donors mobilized into the peripheral blood by granulocyte colony-stimulating factor and intended for allogeneic bone marrow transplantation. The constitutive p21(WAF1/CIP1/SID1) expression levels, measured in three separate harvests, were very low and no significant differences were apparent. Our results support the use of a competitive PCR strategy as a useful tool for clinical purposes, to assess the individual biomolecular response of early hematopoietic progenitors to antiblastic drugs.

Competitive polymerase chain reaction as a method to detect the amplification of bcr-abl gene of chronic myeloid leukemia.

BACKGROUND AND OBJECTIVES: The chimeric product of the bcr-abl rearranged gene is critical in the pathogenesis of chronic myeloid leukemia (CML), yet its role in the progression of the disease remains unclear. There is some evidence that increased bcr-abl expression levels, possibly due to gene amplification, precede the clonal evolution of CML hematopoietic progenitors toward a fully transformed phenotype and might be involved in their resistance to interferon-alpha or tyrosine kinase inhibitors. DESIGN AND METHODS: To quantify the bcr-abl gene both at the genomic and at the transcriptional levels we developed a competitive polymerase chain reaction (PCR) strategy. The competitive PCR technique is based upon the co-amplification of the sample template (target) together with increasing amounts of a DNA fragment (competitor) sharing with the target the primer recognition sites, but differing in size. We constructed a competitor for the quantification of both b2a2 and b3a2 alternative splicing forms of the bcr-abl chimera and established the accuracy and reproducibility of our competitive strategy in a clone of the murine 32DG hematopoietic cell line (32D LG7), which bears a stable integration of a single copy of p210 bcr-abl fusion gene. We utilized this technique to follow, over a period of 200 days, the fusion gene copy numbers and transcription rates in several p210 bcr-abl-transduced 32D cell clones, an experimental condition mimicking the evolution of CML myeloid progenitors in vivo. RESULTS: Our results are consistent with p210 bcr-abl overexpression but not gene amplification associated with their clonal evolution. Increased p210 bcr-abl transcription rate is associated with the abrogation of radiation-induced apoptotic cell death, suggesting a role for the chimeric gene expression level in cell life expectancy after a genotoxic insult. INTERPRETATION AND CONCLUSIONS: We conclude that the assessment of gene amplification and expression might serve to improve prognostic classification and follow-up of CML patients.

Perceptions about advance directives by nurses in a community hospital.

Despite the legal mandate for hospitals to comply with the Patient Self-Determination Act and recommendations by the American Nurses' Association for nurses to advocate for the participation of patients in end-of-life decisions, nurses' compliance has been less than enthusiastic. This study used an exploratory descriptive design and a 10-item self-reported questionnaire, which included both multiple-choice and open-ended questions. This study examined nurses' knowledge and comfort with the implementation of the Patient Self-Determination Act. An analysis of this research shows that two major themes emerged: a need for more education involving advance directives and a desire to have other healthcare workers involved in informing patients about advance directives.

Radiation-induced gadd45 expression correlates with clinical response to radiotherapy of cervical carcinoma.

BACKGROUND: Recent work has identified a category of genes devoted to the control of genomic stability and prevention of cellular evolution. They encode components of cell cycle checkpoint, i.e., regulatory pathways committed to ordered cell cycle transition and fidelity of replicated DNA under adverse environmental conditions, such as those following exposure to genotoxic agents. Gadd45 belongs to the class II family of DNA damage-inducible (DDI) gene, and its role in DNA repair has been proved in many experimental models. The aim of our study was to correlate gadd45 radio-induction with the responsiveness to radiotherapy of cervical carcinomas, a type of cancer most commonly treated with radiotherapy alone. METHODS: By means of a competitive polymerase chain reaction strategy, we compared in 14 patients the gene expression levels before and during external beam radiotherapy, when a dose ranging from 18 to 25 Gy was delivered to the target. RESULTS: We found a correlation between the lack of gadd45 induction and a good clinical response to radiotherapy, in terms of both local control and disease-free survival. CONCLUSION: Our results support the measure of the induction of gadd45, and possibly of other genes required for regulated G1-S checkpoint, as a method useful for prognostic evaluation of cervical carcinoma patients.

Procedure for the quantitation of Gadd45 expression levels in clonal hematopoietic progenitor cells by competitive polymerase chain reaction.

OBJECTIVE: The growth arrest and DNA damage-inducible (gadd) genes represent a family of stress-inducible genes that are coordinately regulated at transcriptional level. Gadd45, in particular, has been linked to a p53-dependent inducible network required for regulated transition from G1 to S phase of cell cycle following genotoxic insult and growth arrest treatments and has seemingly a pivotal role in DNA repair. DESIGN AND METHODS: Here we show that competitive polymerase chain reaction (PCR) is an adequate method to quantitate gadd45 expression levels in hematopoietic progenitor cell line 32D, whose constitutive gene expression is very low. RESULTS: The sensitivity and reproducibility of our strategy support its usefulness for clinical purposes, to assess the DNA repair capacity of highly purified early myeloid progenitors, whose failure may be responsible for either short-term chemotherapy side effects (bone marrow hypoplasia and peripheral blood cytopenia) or long-term consequences of antiblastic drugs (leukemia and myelodysplasia).

Long-term bone marrow cultures in Diamond-Blackfan anemia reveal a defect of both granulomacrophage and erythroid progenitors.

The hematopoietic defect of Diamond-Blackfan anemia (DBA) results in selective failure of erythropoiesis. Thus far, it is not known whether this defect originates from an intrinsic impediment of hematopoietic progenitors to move forward along the erythroid pathway or to the impaired capacity of the bone marrow (BM) microenvironment to support proliferation and differentiation of hematopoietic cells. Reduced longevity of long-term bone marrow cultures, the most physiologic in vitro system to study the interactions of hematopoietic progenitors and hematopoietic microenvironment, is consistent with a defect of an early hematopoietic progenitor in DBA. However, stromal adherent layers from DBA patients generated in a long-term culture system, the in vitro counterpart of BM microenvironment, did not show evidence of any morphologic, phenotypic, or functional abnormality. Our major finding was an impaired capacity of enriched CD34+ BM cell fraction from DBA patients, cultured in the presence of normal BM stromal cells, to proliferate and differentiate along the erythroid pathway. A similar impairment was observed in some DBA patients along the granulomacrophage pathway. Our result points to an intrinsic defect of a hematopoietic progenitor with bilineage potential that is earlier than previously suspected as a relevant pathogenetic mechanism of the disease. The finding of impaired granulopoiesis in some DBA patients underlines the heterogeneity of this rare disorder.

Prior treatment with alpha-interferon does not adversely affect the outcome of allogeneic BMT in chronic phase chronic myeloid leukemia.

BACKGROUND AND OBJECTIVE: Controlled clinical trials have shown that Interferon-alpha (IFN-alpha) is able to control myeloid proliferation and to suppress the Ph+ clonal hemopoiesis in early chronic phase chronic myeloid leukemia (CML): a growing number of patients are treated with this agent from diagnosis. However, if a CML patient has an HLA-identical sibling, bone marrow transplant (BMT) represents the best choice of treatment. Since IFN-alpha is known to modify the immunologic response and to increase marrow fibrosis, information is needed on the outcome of patients transplanted after IFN-alpha treatment. DESIGN AND METHODS: We analyzed retrospectively 32 Ph+ CML patients submitted to BMT in the last 6 years in Institute "Serágnoli". All the patients were in 1st chronic phase, their median age was 37 years, the donors were HLA-identical (27/32) or 1 Ag-mismatched (5/32) siblings. Big BuCy was the conditioning regimen employed for all and GVHD prophylaxis was based on CsA in 4 patients and Csa+MTX in 28 patients; all patients received homogeneous pre and post-transplant supportive care, antimicrobial and antiviral prophylaxis. These patients were divided into 2 groups according to the treatment before BMT: 16 received IFN from diagnosis to BMT (mean dose 6.9 MU/daily) for at least 6 mos (mean 23 mos, range 8-75) and 16 received chemotherapy alone (hydroxyurea [HU]). RESULTS: Hematological recovery was comparable in the two groups: time to 0.5 x 10(9)/L PMN was 20.5 days (range 11-32) in the IFN group and 20 days (range 10-32) in the HU group; time to 50 x 10(9)/L platelets was 28 days (range 20-117) in the IFN group and 27 days (range 20-112) in the HU group. The incidence of acute GVHD was not different in the two groups for any grade of the disease; in patients who survived more than 100 days, chronic GVHD occurred in the two groups with the same frequency. Seven patients died of transplant related mortality (TRM), 4 in the IFN group and 3 in the HU group. Hematological relapse was observed in only one case in the HU group; no cytogenetic relapse occurred. Disease free survivals at 7 years are 61% and 72%, respectively; the difference is not significant. INTERPRETATIONS AND CONCLUSIONS: Notwithstanding the low number of patients included in this study, the data reported here confirm that prior treatment with alpha-IFN does not adversely affect transplant outcome.

Peripheral blood mobilization of hematopoietic stem cells: cytokine-mediated regulation of adhesive interactions within the hematopoietic microenvironment.

Peripheral blood (PB) mobilization of hematopoietic progenitors, presently regarded as an alternative source of cells intended for autologous or allogeneic bone marrow (BM) transplantation, supports a role for cytokines in the regulated adhesion of hematopoietic compartments to the BM microenvironment. Two major consequences might result from cytokine-induced rearrangements of adhesive interactions within the hematopoietic tissue, both potentially relevant for clinical purposes of PB grafts. The first one, arising from abrogated adhesion of hematopoietic stem cells to their microenvironmental 'niche', which is critical for the maintenance of cell cycle quiescence and endurability, might result in some impairment of the long-term repopulating potential of PB grafts. The second and possibly more harmful one is due to the inability of the cytokine to distinguish between normal and transformed cells, and would likely result in graft contamination by tumor cells, increasing the metastasizing potential of hematological malignancies and solid tumors.

Study of second messenger levels and of sugar catabolism enzyme activities in transformed cells resistant to ionizing radiations.

We measured the level of second messengers, the activity of carbohydrate metabolism enzymes, and the resistance to ionizing radiations in normal 32D hematopoietic cells, in v-erbB transformants and in spontaneous transformants. v-erbB and spontaneous transformants were resistant to radiations as compared with their normal counterpart. The second messenger diacylglycerol was elevated in radioresistant clones. Only v-erbB transformants showed increase of the activities of enolase and glucose-6-phosphate dehydrogenase. v-erbB-transformed NIH/3T3 cells, selected as control, showed identical correlation between radioresistance, increase of diacylglycerol, and of enolase and glucose-6-phosphate dehydrogenase activity. These results indicate that increase of diacylglycerol is correlated with resistance to the killing effect of ionizing radiations and could be proposed as a marker of radioresponse.

Erythropoietin increases the radioresistance of a clonal hematopoietic progenitor cell line expressing a transgene for the erythropoietin receptor.

Erythropoietin (Epo) is a serum glycoprotein growth factor required for the survival, proliferation and differentiation of committed erythroid progenitor cells. In the present study, we sought to determine whether the action of Epo via its receptor is also implicated in the repair of radiation-induced cell damage. Overexpression of the Epo receptor (Epo-R) was achieved as a result of transfection of the 32D cl 3 clonal hematopoietic cell line. These clonal lines allowed us to investigate the effects of Epo on the radiation sensitivity in vitro of a clonal murine hematopoietic progenitor cell line. Low level expression of Epo-R on many hematopoietic cell types was thus circumvented. Ligand binding of Epo resulted in increased radioresistance of 32D cl 3 subclonal lines expressing the Epo-R transgene. The D0 of 32D Epo-R cells at 1.49 Gy/min was 1.33 Gy and n was 1.39. The D0 of parental clonal cell line 32D cl 3 cells at 1.49 Gy/min was 1.36 Gy and n was 1.39. In contrast, at the low dose rate of 0.0595 Gy/min, the D0 of 32D Epo-R cells was 2.0 Gy and n was 1.24, while parental clonal line 32D cl 3 showed a D0 of 1.35 Gy and n was 1.39. The increased radioresistance was statistically significant at low dose rate (p < 0.05). Combined exposure to Epo and interleukin 3 (IL-3) increased proliferation of 32D Epo-R cells but did not induce a detectable further increase in radioresistance. Temporal dissociation between growth factor-activated tyrosine phosphorylation of intracellular substrates, and the radioprotective effect was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of p210 bcr/abl increases hematopoietic progenitor cell radiosensitivity.

PURPOSE: The cytogenetic finding of the Ph1+ chromosome and its molecular biologic marker bcr/abl gene rearrangement in cells from patients with chronic myeloid leukemia are associated with a proliferative advantage of the Ph1+ clone in vivo. Although the transition to the acute terminal phase or blastic crisis is often associated with additional cytogenetic abnormalities, the molecular events which correlate the initial cytogenetic lesion with the terminal phase are poorly understood. Defective cellular DNA repair capacity is often associated with chromosomal instability, increased mutation frequency, and biologic alterations. METHODS AND MATERIALS: We, therefore, tested whether the protein product of the bcr/abl translocation (p210) could alter DNA repair after gamma-irradiation of murine cell lines expressing the bcr/abl cDNA. RESULTS: The 32D cl 3 parent, 32D cl 3 pYN (containing the control vector plasmid) and each of two sources of 32D cl 3 cells expressing p210 bcr/abl cDNA (32D-PC1 cell line and 32D-LG7 subclone) showed a D0 of 1.62, 1.57, 1.16, and 1.27 Gy, respectively. Thus, expression of the p210 bcr/abl product induced a significant (p < 0.05) increase in radiosensitivity at the clinically relevant radiation therapy dose-rate (1.16 Gy/min). The increased radiosensitivity of p210 bcr/abl expressing cells persisted if cells were held before plating in a density-inhibited state for 8 hr after gamma-irradiation, indicating little effect on the repair of potentially lethal gamma-irradiation damage. The IL-3 dependent parent 32D cl 3 cells demonstrated programmed cell death in the absence of growth factor or following gamma-irradiation to 200 cGy. Expression of bcr/abl cDNA in the 32D-PC1 and 32D-LG7 sub clones abrogated IL-3 requirement of these cell lines and inhibited gamma-irradiation induced programmed cell death. CONCLUSION: These data suggest a role for bcr/abl p210 in amplifying gamma-irradiation DNA damage or broadly inhibiting DNA repair, conditions that may stimulate further cytogenetic alterations in hematopoietic cells.

M-07e cell bioassay detects stromal cell production of granulocyte-macrophage colony stimulating factor and stem cell factor in normal and in Diamond-Blackfan anemia bone marrow.

Ten healthy donors and four patients with Diamond-Blackfan anemia (DBA) have been investigated for granulocyte-macrophage colony stimulating factor (GM-CSF) and stem cell factor (SCF) production by bone marrow-enriched fibroblasts (BMEF) in a highly sensitive biological assay on growth factor-dependent M-07e cells. M-07e cells detected active soluble kit-ligand from normal bone marrow fibroblasts as well as from DBA BMEF which produce constitutively significant amounts of SCF. Interleukin 1 beta (IL-1 beta) induced a significant increase of soluble SCF from both normal and DBA BMEF. GM-CSF was undetectable in unstimulated cultures, while its production by bone marrow microenvironmental cells was documented for both normal and DBA patients after IL-1 beta stimulation in vitro.