Compelling evidence have demonstrated that bulk tumors can arise from a unique subset of cells commonly termed “cancer stem cells” that has been proposed to be a strong driving force of tumorigenesis and a key mechanism of therapeutic resistance. Recent advances in epigenomics have illuminated key mechanisms by which epigenetic regulation contribute to cancer progression. In this review, we present a discussion of how deregulation of various epigenetic pathways can contribute to cancer initiation and tumorigenesis, particularly with respect to maintenance and survival of cancer stem cells. This information, together with several promising clinical and preclinical trials of epigenetic modulating drugs, offer new possibilities for targeting cancer stem cells as well as improving cancer therapy overall.
Objective: As the current therapeutic strategies for human hepatocellular carcinoma (HCC) have been proven to have limited effectiveness, immunotherapy becomes a compelling way to tackle the disease. We aim to provide humanised mouse (humice) models for the understanding of the interaction between human cancer and immune system, particularly for human-specific drug testing. Design: Patient-derived xenograft tumours are established with type I human leucocyte antigen matched human immune system in NOD-
scid Il2rg
−/− (NSG) mice. The longitudinal changes of the tumour and immune responses as well as the efficacy of immune checkpoint inhibitors are investigated. Results: Similar to the clinical outcomes, the human immune system in our model is educated by the tumour and exhibits exhaustion phenotypes such as a significant declination of leucocyte numbers, upregulation of exhaustion markers and decreased the production of human proinflammatory cytokines. Notably, cytotoxic immune cells decreased more rapidly compared with other cell types. Tumour infiltrated T cells have much higher expression of exhaustion markers and lower cytokine production compared with peripheral T cells. In addition, tumour-associated macrophages and myeloid-derived suppressor cells are found to be highly enriched in the tumour microenvironment. Interestingly, the tumour also changes gene expression profiles in response to immune responses by upregulating immune checkpoint ligands. Most importantly, in contrast to the NSG model, our model demonstrates both therapeutic and side effects of immune checkpoint inhibitors pembrolizumab and ipilimumab. Conclusions: Our work provides a model for immune-oncology study and a useful parallel-to-human platform for anti-HCC drug testing, especially immunotherapy.
Chemoresistance is a primary cause of treatment failure in cancer and a common property of tumor-initiating cancer stem cells. Overcoming mechanisms of chemoresistance, particularly in cancer stem cells, can markedly enhance cancer therapy and prevent recurrence and metastasis. This study demonstrates that the delivery of Epirubicin by nanodiamonds is a highly effective nanomedicine-based approach to overcoming chemoresistance in hepatic cancer stem cells. The potent physical adsorption of Epirubicin to nanodiamonds creates a rapidly synthesized and stable nanodiamond–drug complex that promotes endocytic uptake and enhanced tumor cell retention. These attributes mediate the effective killing of both cancer stem cells and noncancer stem cells in vitro and in vivo. Enhanced treatment of both tumor cell populations results in an improved impairment of secondary tumor formation in vivo compared with treatment by unmodified chemotherapeutics. On the basis of these results, nanodiamond-mediated drug delivery may serve as a powerful method for overcoming chemoresistance in cancer stem cells and markedly improving overall treatment against hepatic cancers.
Liver cancer is the second most lethal cancer in the world with limited treatment options. Hepatocellular carcinoma (HCC), which accounts for more than 80% of all liver cancers, has had increasing ...