Alterations of biomechanics in cancer and normal cells induced by doxorubicin.

Mechanical properties of biological structures play an important role in regulating cellular activities and are critical for understanding metabolic processes in cancerous cells and the effects of drugs. For some cancers, such as acute myeloid leukaemia, chemotherapy is one of preferential methods. However, due to the lack of selectivity to cancer cells, cytostatic agents cause toxicity to normal tissues. Here, we study the effect of doxorubicin (DOX) on the mechanical properties of DNA molecules, leukemic blast cells and erythrocytes, using optical tweezers. In addition, we controlled the subcellular distribution of the drug by confocal microscopy. Our results indicated that doxorubicin affects mechanical properties of cellular structures. In all cases the drug reduced mechanical strength of examined objects. For the leukemic cells the drug subcellular distribution was predominantly nuclear with some particulate cytoplasmic fluorescence. In erythrocytes, doxorubicin showed fluorescence mainly in cytoplasm and plasma membrane. The lowering of blast cells stiffness may be due to the interaction of doxorubicin with nuclear structures, especially with nucleic acids, as our studies with DNA confirmed. In addition, it is known that DOX inhibits the polymerization of actin and thus cytoskeletal modification may also be important in reducing of cell mechanical strength. In the case of erythrocytes - the non-nucleated cells, a significant effect on the decrease of cell stiffness, besides the cytoskeleton, may have the interaction of the drug with the cell membrane. Experiments with model phospholipid membranes confirmed that observed increase in cell elasticity originates, among other things, from the drug incorporation in the lipid membrane itself. The lowering of mechanical strength of leukemic cells may have an significant impact on the effectiveness of chemotherapy. However, the fact that doxorubicin interacts not only with proliferating cancer cells, but also with the health ones may explains the high toxicity of the drug at the therapeutic concentrations. Our observations also suggest that chemotherapy with doxorubicin may decrease the risk of vascular complications in acute leukemia, due to increasing the cell elasticity.

Significance of OCT1 Expression in Acute Myeloid Leukemia.

Organic cation transporter 1 (OCT1) is one of the membrane proteins in the large solute carrier (SLC) family. It participates in the transport of organic cations, i.e. nutrients, neurotransmitters, metabolites or drugs in an electrogenic manner and translocate various cationic cytostatics. Knowledge concerning the expression of drug transporters in tumor cells may help to develop cytotoxic agents that are targeted to specific tumors. OCT1 expression and its relationship to the proliferation of cancer cells, development of metastases and resistance to chemotherapy has been observed in solid tumors. There is no data concerning the significance of OCT1 expression in the clinical course and treatment results in acute myeloid leukemia (AML). The objective of the study was firstly to evaluate OCT1 mRNA expression in patients with newly diagnosed de novo AML, and secondly to compare the obtained results to the healthy control group as well as analyze them according to leukemia subtypes, CD34 expression, cytogenetic and molecular factors and treatment results. 101 patients with AML, excluding the subtype classified as M3 by French-American-British (FAB) criteria, were analyzed. The control group consisted of 26 healthy individuals. The evaluated material was bone marrow (BM). Real-time quantitative polymerase chain reaction (RQ-PCR) was used in the study as a method of evaluating OCT1 mRNA expression. The study showed a statistically significant lower expression of OCT1 mRNA in patients with AML in comparison to the control group. The level of OCT1 mRNA expression was lowest for CD34+ leukemia. No significant correlation between OCT1 mRNA expression and cytogenetic and molecular factors was observed. A significant influence of OCT1 mRNA expression on the clinical outcome of the disease was observed: patients with lower expression had higher chances of achieving complete remission (CR) and longer overall survival (OS).

The expression of Toll-like receptors in patients with acute myeloid leukemia treated with induction chemotherapy.

Toll-like receptors play an important role in the host defense against microorganisms. TLRs are mainly expressed in human immune-related cells, such as monocytes, neutrophils, macrophages, dendritic cells, T cells, B cells and NK cells. The expression or up-regulation of TLRs has been demonstrated in some tumors and tumor cell lines but the role of TLRs in pathogenesis and development of acute leukemias remains unclear. The aim of this study was to evaluate the expression of TLR2, TLR4 and TLR9 and their significance as prognostic factors in patients with acute leukemias treated with induction chemotherapy. 103 patients with newly diagnosed acute myeloid leukemia (AML) were evaluated (47 females and 56 males). The median age of patients was 51 years. Using quantitative reverse transcriptase PCR, the mRNA expression of genes TLR2, TLR4 and TLR9 was measured. The mRNA expression of TLR2 and TLR4 was significantly higher in patients with NR than in patients with CR and CRi. We especially observed that mRNA expression of TLR2 and TLR4 was significantly higher in patients with myelomonocytic and monoblastic acute leukemia than in patients with other types of AML. The mRNA expression of TLR2 and TLR4 was higher in AML patients than in healthy individuals, although there was no statistically significant difference. Patients with higher mRNA expression of TLR2 and TLR4 had significantly shorter OS than patients with lower mRNA expression of TLR2 and TLR4. Multivariate analysis showed that mRNA expression of TLR2 and the age of patients were independent factors associated with treatment response. Our results suggest that TLRs could be an independent prognostic factor for response rate after induction therapy in patients with acute myeloid leukemias.

Azacitidine in outpatient treatment - single center experience.

AIM OF THE STUDY: Azacitidine is a hypomethylating agent which is used in the treatment of myelodysplastic syndromes, acute myeloid leukemia and chronic myelomonocytic leukemia. Because of good tolerance to the drug, azacitidine can be administered both during hospitalization and in an outpatient setting. The aim of our retrospective analysis was to assess the efficacy of azacitidine treatment in patients with a myelodysplastic syndrome and with acute myeloid leukemia who had received treatment in hospital and in an ambulatory care setting. Offsets in the course of azacitidine administration and discontinuations of treatment have a negative impact on patients' response to the therapy. MATERIAL AND METHODS: The study included 31 patients. Sixteen patients received azacitidine in an ambulatory care setting, 15 patients within their hospitalization. RESULTS: A hematologic response was achieved in 48% of the patients. Forty-one percent of the cycles were delayed. In an outpatient setting, 62% of the cycles were administered systematically, while during hospitalization the patients received 54% of cycles on time. Administrative problems caused the delay of 26% of the cycles. CONCLUSIONS: Azacitidine has a high tolerance level and a high safety profile which allows for its use in an outpatient care setting. Outpatient administration of azacitidine is feasible and safe without compromising efficacy.

The expression of Toll-like receptors and development of severe sepsis in patients with acute myeloid leukemias after induction chemotherapy.

Toll-like receptors play an important role in the host defense against microorganisms. Sepsis remains a common cause of mortality in patients with acute myeloid leukemia (AML) treated with intensive induction chemotherapy. The expression of TLRs and their association with the development of sepsis in patients with acute myeloid leukemia remains unclear. The aim of this study was to investigate the associations between expression of TLR2, TLR4 and TLR9 and occurrence of sepsis in patients treated with intensive induction chemotherapy for AML. A total of 103 patients with newly diagnosed AML were evaluated. Bone marrow samples were taken before induction therapy. Using quantitative reverse transcriptase PCR, the mRNA expression of genes TLR2, TLR4 and TLR9 was measured. Neutropenic fever occurred in 98 patients. We identified 20 episodes of severe sepsis (20%). In patients with neutropenic fever, the mRNA expression of TLR2 and TLR4 was significant higher in septic patients than in patients without sepsis symptoms (ΔCt TLR2 0.93 ± 0.82 vs 0.78 ± 0.85 and ΔCt TLR4 0.38 ± 0.29 vs 0.34 ± 0.25). Moreover, we observed that expression of TLR2 and TLR4 was significantly higher in patients with AML and bacterial infection in comparison with group with separate fungal infection (ΔCt TLR2 1.15 ± 1.06 vs 0.66 ± 0.51 and ΔCt TLR4 0.45 ± 0.38 vs 0.21 ± 0.19). Our results suggest that TLRs could be an independent factor for the development of sepsis in patients with acute myeloid leukemias after intensive induction chemotherapy. This observation should be validated by larger study.

Expression of Eph A4, Eph B2 and Eph B4 receptors in AML.

Eph receptors represent the largest subfamily of receptor tyrosine kinases (RTKs). The up- regulation of Eph receptors has been documented in various solid tumors, where it often correlates with poor prognosis. Their significance in hematologic malignancies is still unclear. This study aimed to investigate the expression of Eph A4, Eph B2, and Eph B4 mRNA in non - M3 AML patients and determine their prognostic significance. Bone marrow samples from 101 newly diagnosed non - M3 AML patients and 26 healthy controls for comparison were quantified by real time reverse transcriptase polymerase chain reaction (RT-PCR), and the comparative cycle threshold (Ct) method was used to determine their relative expression levels to GUS control gene. The results showed that expression of all selected Eph receptors was significantly lower in AML patients comparing to controls. It also differed according to FAB subtypes. The decreased expression levels of Eph A4 were associated with higher leukocytes (p = 0.022) and blast cell counts (p = 0.001), and unfavorable FLT3-ITD mutation. Our study revealed significant correlation between lower EphB2 expression levels, and higher complete remission rate (p = 0.009724) and longer overall survival. Additionally, we found that patients with shorter RFS had decreased EphB4 expression (p = 0.00). In conclusion, the results suggest the prognostic impact of decreased expression levels of some Eph receptors in AML patients.