ISSN 16076729, Doklady Biochemistry and Biophysics, 2011, Vol. 437, pp. 105–108. © Pleiades Publishing, Ltd., 2011. Original Russian Text © K.N. Kashkin, E.A. Musatkina, A.V. Komelkov, D.A. Sakharov, E.V. Trushkin, E.A. Tonevitsky, T.V. Vinogradova, E.P. Kopantzev, M.V. Zinovyeva, O.V.Kovaleva, K.A. Arkhipova, I.B. Zborovskaya, A.G. Tonevitsky, E.D. Sverdlov, 2011, published in Doklady Akademii Nauk, 2011, Vol. 437, No. 6, pp. 837–841. 105 Paclitaxel is a natural substance from the group of taxanes and one of the most widely used drugs in che motherapy of malignant tumors, including the non small cell lung cancer (NSCLC). Treatment of patients with advanced NSCLC with paclitaxel alone or in combination with other drugs led to complete or partial tumor regression in at most 41% of patients [1]. Individual selection of drugs that are effective for a particular patient is one of the hottest approaches in the strategy to improve the results of chemotherapeu tic treatment of cancer patients. This work is dedicated to finding new markers and studying the resistance mechanisms of lung cancer to paclitaxel. The main mechanism of action of paclitaxel is the blockade of cell division due to its specific binding to β3 tubulin and stabilization of microtubules. An increased expression of some βtubulin isotypes corre lates with resistance to paclitaxel and the degree of malignancy of tumors of the lung, prostate, ovary and other tissues. The same result can be caused by muta tions of βtubulins, although the clinical significance of mutations is controversial (see reviews [2, 3]). It is known that the resistance of tumor cells to paclitaxel may be associated with an increased expres sion or polymorphism of some ABCtransporters responsible for multidrug resistance [4] as well as with activity of growth factor receptors (EGFR and HER 2), proteins LIMK1, LIMK2, TGFB1, STMN1, spin dle checkpoint proteins, apoptosis regulators, and others [2, 3]. The use of DNA microchips [5–10] made it possi ble to reveal the sets of genes whose expression corre lates with chemoresistance of lung cancer cells. How ever, the sets of genes that, with a certain probability, may be involved in resistance development, which were proposed by different authors, differ. In addition, the genes detected in cell cultures may be uninforma tive for predicting the response of patients to chemo therapy [11]. At the same time, studies of clinical specimens only may give ambiguous results due to polymorphisms, which lead to a high interindividual variability of systems involved in the development of chemoresistance of cancer patients, as well as because of chemotherapy regimens that usually include several drugs. To search for new informative markers and to reveal the molecular mechanisms of drug resistance in tumors, we studied the relationship between the sensi tivity of lung cancer cells to paclitaxel and the expres sion of a wide range of genes using the new microchip platform Affymetrix Human GeneChip ST1.0, which contained probes for over 28000 human mRNAs. As a biological model, we used lung cancer cells of six lines derived from ATCC (A549, NCIH292, NCI H460, and NCIH1299) and ECACC (NCIH322 and NCIH358). Although the sensitivity of certain lines to various drugs is known (http://dis cover.nci.nih.gov/cellminer/), we redefined the IC50 of paclitaxel for all cells using the MTT technique [12] in order to eliminate the effect of subculturing of cells on their sensitivity to the drug. For each cell line, we analyzed the results of at least three significant mea surements (Fig. 1). Hybridization of labeled samples prepared from total cell RNA with microchips was performed using the equipment and method of Affymetrix. The results of hybridization were processed by the RMA algo rithm using the xps library (Christian Stratowa; http://www.bioconductor.org) in R system. Fluores cence signals were filtered using I/INI algorithm [13]; signals with random variation were ignored. Genes Potentially Associated with Resistance of Lung Cancer Cells to Paclitaxel K. N. Kashkin a , E. A. Musatkina b , A. V. Komelkov b , D. A. Sakharov c , E. V. Trushkin c , E. A. Tonevitsky c , T. V. Vinogradova a , E. P. Kopantzev a , M. V. Zinovyeva a , O. V. Kovaleva b , K. A. Arkhipova b , I. B. Zborovskaya b , Corresponding Member of the RAS A. G. Tonevitsky c , and Academician E. D. Sverdlov a Received December 24, 2010 DOI: 10.1134/S1607672911020153 a Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. MiklukhoMaklaya 16/10, Moscow, 117997 Russia b Blokhin Cancer Research Center, Russian Academy of Medical Sciences, Kashirskoe sh. 24, Moscow, 115478 Russia c AllRussia Institute of Physical Culture and Athletics, Elizavetinskii per. 10, Moscow, 105005 Russia BIOCHEMISTRY, BIOPHYSICS AND MOLECULAR BIOLOGY