Genes of cell-cell interactions, chemotherapy detoxification and apoptosis are induced during chemotherapy of acute myeloid leukemia

<p>Abstract</p> <p>Background</p> <p>The molecular changes <it>in vivo </it>in acute myeloid leukemia cells early after start of conventional genotoxic chemotherapy are incompletely understood, and it is not known if early molecular modulations reflect clinical response.</p> <p>Methods</p> <p>The gene expression was examined by whole genome 44 k oligo microarrays and 12 k cDNA microarrays in peripheral blood leukocytes collected from seven leukemia patients before treatment, 2–4 h and 18–24 h after start of chemotherapy and validated by real-time quantitative PCR. Statistically significantly upregulated genes were classified using gene ontology (GO) terms. Parallel samples were examined by flow cytometry for apoptosis by annexin V-binding and the expression of selected proteins were confirmed by immunoblotting.</p> <p>Results</p> <p>Significant differential modulation of 151 genes were found at 4 h after start of induction therapy with cytarabine and anthracycline, including significant overexpression of 31 genes associated with p53 regulation. Within 4 h of chemotherapy the BCL2/BAX and BCL2/PUMA ratio were attenuated in proapoptotic direction. FLT3 mutations indicated that non-responders (5/7 patients, 8 versus 49 months survival) are characterized by a unique gene response profile before and at 4 h. At 18–24 h after chemotherapy, the gene expression of p53 target genes was attenuated, while genes involved in chemoresistance, cytarabine detoxification, chemokine networks and T cell receptor were prominent. No signs of apoptosis were observed in the collected cells, suggesting the treated patients as a physiological source of pre-apoptotic cells.</p> <p>Conclusion</p> <p>Pre-apoptotic gene expression can be monitored within hours after start of chemotherapy in patients with acute myeloid leukemia, and may be useful in future determination of therapy responders. The low number of patients and the heterogeneity of acute myeloid leukemia limited the identification of gene expression predictive of therapy response. Therapy-induced gene expression reflects the complex biological processes involved in clinical cancer cell eradication and should be explored for future enhancement of therapy.</p

Cavity-Enhanced Overtone Spectroscopy of Methanol in Aprotic Solvents: Probing Solute-Solvent Interactions and Self-Associative Behavior

Methanol in aprotic solvents can serve as a case study for self-association via hydrogen-bonding, which is an important process in many biological and environmental systems. Incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS), which provides enhanced sensitivity relative to conventional single-pass absorption techniques, has been used to characterize the third “free” O–H stretching overtone of methanol in four aprotic solvents (CCl4, CHCl3, CH2Cl2, and C6H6), including the transition wavenumber, bandwidth, and molar absorptivity. The absorption band characteristics indicate an increasing degree of nonspecific methanol–solvent interaction with increasing solvent dielectric constant, except in the case of benzene, which shows evidence of a specific, H−π interaction. Density functional theory with the polarizable continuum model was used to complement the results by assessing the accuracy of computational methods for calculating anharmonic O–H stretching frequencies. Finally, the self-association of methanol in these solvents at 298 K was also investigated using the concentration dependence of the overtone absorption intensity. The propensity for methanol’s self-association in the solvents studied increases in the order: CH2Cl2 ∼ CHCl3 \u3c C6H6 \u3c CCl4