Deep sequencing reveals two Jurkat subpopulations with distinct miRNA profiles during camptothecin-induced apoptosis

Abstract

microRNAs (miRNAs) are small non-coding RNAs of about 19-25 nt that regulate gene expression post-transcriptionally under various cellular conditions, including apoptosis. The miRNAs involved in modulation of apoptotic events in T cells are partially known. However, heterogeneity associated with cell lines makes it difficult to interpret gene expression signatures especially in cancer-related cell lines. Treatment of Jurkat T cell leukemia cell line with the universal apoptotic drug, camptothecin, resulted in identification of two Jurkat sub-populations: one that is sensitive to camptothecin and the other being rather intrinsically resistant. We sorted apoptotic Jurkat cells from the non-apoptotic ones prior to profiling miRNAs through deep sequencing. Our data showed that a total of 184 miRNAs were dysregulated. Interestingly, apoptotic and non-apoptotic sub-populations exhibited a distinct miRNA expression profile. In particular, 6 miRNAs were inversely expressed in these two sub-populations. The pyrosequencing results were validated by real time qPCR. Altogether these results suggest that miRNAs modulate apoptotic events in T cells and that cellular heterogeneity requires careful interpretation of miRNA expression profiles obtained from drug-treated cell lines.