Long non-coding RNAs (lncRNAs) and methods of using them diagnostically and therapeutically for treatment of cancer, stem cell therapy, or regenerative medicine are disclosed. In particular, the invention relates to lncRNAs that that play roles in regulation of genes involved in cell proliferation, differentiation, and apoptosis. Such lncRNAs can be used as biomarkers to monitor cell proliferation and differentiation during cancer progression or tissue regeneration. One of the identified lncRNAs, referred to as PANDA (a P21-Associated NcRNA, DNA damage Activated), inhibits the expression of apoptotic genes normally activated by the transcription factor NF-YA. Inhibitors of PANDA sensitize cancerous cells to chemotherapy and can be used in combination with chemotherapeutic agents for treatment of cancer.
