Histone variant H2AFV expression defines functionally distinct cancer subpopulations [RNA-seq]

Tumors are composed of cellular subpopulations with varying degree of proliferative and tumorigenic potential. Here, we identify inter- and intra-tumor heterogeneous expression of histone variant H2AFV in numerous cancer types, with high H2AFV expression correlating with cancer stem cells, poorly differentiated tumors and inferior patient survival. Depletion of H2AFV impairs proliferation, invasiveness, tumorigenicity and tumor initiating cell frequency of glioblastoma. Mechanistically, H2AFV regulates chromatin accessibility of both active and repressive complexes at the promoters and enhancers of genes: the former activates genes involved in cell proliferation/self-renewal and invasiveness while the latter suppresses cellular differentiation in cancer stem cells. Our studies uncover H2AFV as an important epigenetic determinant in cancer stem cell fate and a significant contributor of intratumor heterogeneity. RNA-seq from glioblastoma stem cell specimens (TS-543) following treatment either with non-targeting or targeting shRNA.