Isolation and identification of patient-derived liver cancer stem cells and development of personalized treatment strategies
Liver cancer is a devastating disease characterized by its molecular complexity and the insidious behavior of liver cancer stem cells (LCSCs), which drive the metastasis and recurrence. However, the heterogeneity of molecular markers of LCSCs has hindered the development of effective methods to isolate them. This study introduced a pioneering approach to isolate and culture LCSCs from primary tumor tissues, leveraging mouse embryonic fibroblasts (MEFs) as a feeder cell to provide the niche in conjunction with using defined medium, which stands in stark contrast to traditional techniques, and promised to revolutionize our understanding of LCSCs. Total seventeen cell strains were directly isolated from 24 patients' tissues without sorting, seven of which could be maintained long-term culture as colony growth on MEFs, which is unique characteristics of stem cells. Cloned cells formed a round packed morphology on MEFs and could be cryopreserved and re-cultured. Even 10 of cloned cells could form xenografts of human liver cancers in immunodeficient mice, indicating high tumorigenicity. Thus, cloned cells could be designated as liver cancer stem cells. Our further investigation found that reported putative liver cancer stem cell markers were all expressed in cloned cells, and stemness of cancer stem cells could well maintained under our developed culture conditions when compared to those under traditional suspension conditions. Furthermore, our findings revealed a distinct molecular landscape within hepatocellular carcinomas (HCCs), pinpointing a C2 subtype with profound implications for personalized medicine and the development of targeted therapies. By illuminating the unique responses of this subtype to chemotherapeutic agents, our research not only advances the frontiers of liver cancer biology but also charts a course for more effective, patient-specific treatment strategies. Overall design: ALDH-positive HCC2 CSCs were cultured in three different ways: on MEFs, in suspension conditions, and in differentiation conditions using DMEM medium containing 10% FBS.