HighTUBB2Aexpression in childhood T-ALL is correlated with the clinical outcome

Abstract

Introduction Microtubules are polymers that perform functions such as mitosis, intracellular transport, cell morphology, and ciliary and flagellar motility. Since microtubules are taking active part in cell division, they are among direct targets of several antimitotic drugs. Methods Expression levels of tubulin isotypes were analyzed in microarray data of childhood diagnostic T-ALL samples (n = 31) and healthy thymocytes (n = 7). Findings were validated with qPCR in separate T-ALL cohort (n = 48), and clinical correlation analyses were performed.TUBB2A's effects were tested with siRNA-mediated knockdown in MOLT4 cell line, and apoptosis assay was carried out at 24, 48, and 72 hours time points. Results In microarray data,TUBB2Awas found to be the only differentially expressed tubulin isotype (adj.Pvalue = .01), which was validated by qPCR (P = .02). Samples representing differentiation stages of T cell showed an increasing trend ofTUBB2Atoward mature T-cell stage.TUBB2Aexpression was significantly higher in high-risk group patients (P = .026) and in a group with WBC counts >100 (x10(9)cells/L) (P = .029). HighTUBB2Awas also found to be a predictor of shorter OS (P = .029) and RFS (P = .042). Conclusion Aberrant expression of TUBB isotypes can affect the balance of microtubules or microtubule-associated proteins, which might lead to drug resistance/relapse. Contribution of cytoskeleton proteins to drug resistance needs further investigation, and understanding aberrant expression and mode of action of microtubules will improve therapy strategies.