Rapid induction of pancreatic cancer cells to cancer stem cells via heterochromatin modulation.

Mounting evidence supports that CSCs (cancer stem cells) play a vital role in cancer recurrence. Therefore elimination of CSCs is currently considered to be an important therapeutic strategy for complete remission. A major obstacle in CSC research is the obtainment of sufficient numbers of functional CSC populations. Here, we established a method to induce bulk pancreatic cancer cells to CSCs via heterochromatin modulation. Two pancreatic cancer cell lines Panc1 and Bxpc3 were cultured for 4 days in inducing medium (mTeSR containing FBS, B27, MEK inhibitor, GSK3 inhibitor, and VPA), and another 2 days in sphere culture medium (mTeSR supplemented with B27). Then the induced cells were dissociated into single cells and cultured in suspension in sphere culture medium. It was found that the majority of induced cells formed spheres which could grow larger and be passaged serially. Characterization of Panc1 sphere cells demonstrated that the sphere cells expressed increased pancreatic cancer stem cell surface markers and stem cell genes, were more resistant to chemotherapy, and were more tumorigenic in vivo, indicating that the induced sphere cells acquired CSC properties. Thus, the inducing method we developed may be used to obtain a sufficient number of CSCs from cancer cells, and contribute to the research for CSC-targeting therapy.