Journal of cancer stem cell research最新文献

Prostate cancer (PCa) is one of the most common neoplasms that metastasize to bone. The aim of this study was to determine if osteoclasts play a role in the seeding of disseminated tumor cells to the bone marrow by mobilizing hematopoietic stem cells (HSCs) out of their marrow niche. Human PC-3^Luc cells were introduced into male SCID mice by intracardiac (i.c.) injection after mice were treated with the antiresorptive agent Zoledronic Acid (bisphosphonate (BP)) and/or AMD3100, which mobilizes HSCs out of the marrow. Short term homing of PC-3 was assessed at 24 hours by QPCR for human Alu and luciferase and HSC number was determined by FACS. Mice also received pre and/or post treatments of BP by intraperiteneal (i.p.) injections, in addition to PC-3 ^luc by intratibial (i.t.) injections. TRAP assays were used to determine the osteoclast (OC) number in both studies. AMD3100 enhanced the release of HSCs from the bone marrow, while BP increased the retention of HSCs. PCa entry into bone was facilitated in AMD3100, BP, and AMD3100+BP treatments. Before PCa injection, the number of TRAP+ OC was increased in mice treated with AMD3100, while treatment with BP resulted in relatively lower TRAP+ OCs. TRAP+ OCs were not detected in the AMD3100 + BP treatment. After PCa injection, however, the number of TRAP+ OCs was dramatically increased, but did not differ significantly amongst the treatment groups. The pre and post BP treatments in the Nude mice decreased the size of PCa lesions in the tibia compared to the control. The results indicate that OC activation is not necessary for PCa metastasis to bone at the earliest stages. These findings are critical in proving that OCs' contribution to metastasis occur during the growth phase of the tumor rather than at the initiation phase.

Breast cancer (BC) cells (BCCs) exist within a hierarchy beginning with cancer stem cells (CSCs). Unsorted BCCs interact with mesenchymal stem cells (MSCs) to induce regulatory T cells (T_regs). This study investigated how distinct BCC subsets interacted with MSCs to polarize T-cell response, T_regs versus T helper 17 (Th17). This study tested BC initiating cells (CSCs) and the relatively more mature early and late BC progenitors. CSCs interacted with the highest avidity to MSCs. This interaction required CXCR4 and connexin 43 (Cx43)-dependant gap junctional intercellular communication (GJIC). This interaction induced T_reg whereas interactions between MSCs and the progenitors induced Th17 response. The increases in T_reg and Th17 depended on MSCs but not CTLA-4, which was increased in the presence of MSCs. Studies with BM stroma (fibroblasts) and MSCs from the same donors, indicated specific effects of MSCs. In total, MSC-CSC interaction required CXCR4 for GJIC. This led to increased T_regs and TGFβ, and decreased Th17. In contrast, late and early BCCs showed reduced formation of GJIC, decreased T_reg and increased Th17 and IL-17. These findings have significance to the methods by which CSCs evade the immune response. The findings could provide methods of intervention to reverse immune-mediated protection and support of BC.

Ectopic gene expression through introduction of cDNA and gene silencing by RNA interference each facilitate the elucidation of molecular pathways in both normal and pathologic states. As transfection efficiency in some primary and established cells is low, lentivirus based expression systems with high infection rates can improve experimental design. For example, glioblastoma cells and particularly the cancer stem cell (CSC) fraction can be difficult to transfect but are amenable to viral infection. Greater utilization of lentivirus for expression of cDNA and shRNA in CSCs may be limited due to technical challenges, including elimination of pro-differentiating fetal bovine serum (FBS). We therefore generated a subline of 293Ts that can proliferate and efficiently produce virus in CSC media, designated CSC293Ts. We provide detailed protocols for the generation of CSC293Ts and for the production of lentivirus for CSC infection using glioblastoma as a model. Our data demonstrate that serum free media from CSC293Ts consistently produces greater than 80% infection rates without virus concentration. We believe that the detailed protocols provided here can be adapted for multiple cell types for broad utility.

Several evidences suggest that a small population of cells known as cancer stem cells (CSCs) or tumor initiating stemlike cells within a tumor is capable of tumor initiation, maintenance and propagation. Recent publications have supported the existence of CSCs in pancreatic tumors. The pancreatic stem/progenitor cells, which express self-renewal markers, are identified to be present in the peribiliary gland. Based on the CSC hypothesis, mutations can lead to the transformation of stem/progenitor cells or differentiated cells into CSCs. The pancreatic CSCs express a wide array of markers such as CD44, CD24, ESA, CD133, c-MET, CXCR4, PD2/Paf1 and ALDH1. The CSCs are isolated based on surface markers or by other methods such as ALDEFLOUR assay or Hoechst 33342 dye exclusion assay. The isolated cells are further characterized by in vitro and in vivo tumorigenic assays. The most important characteristics of CSCs are its ability to self-renew and impart drug resistance towards chemotherapy. Moreover, these distinct cells display alteration of signaling pathways pertaining to CSCs such as Notch, Wnt and Shh to maintain the self-renewal process. Failure of cancer treatment could be attributed to the therapy resistance exhibited by the CSCs. Metastasis and drug resistance in pancreatic cancer is associated with epithelial to mesenchymal transition (EMT). Furthermore, mucins, the high molecular weight proteins are found to be associated with pancreatic CSCs and EMT. Understanding the underlying molecular pathways that aid in the metastatic and drug resistant nature of these distinct cells will aid in targeting these cells. Overall, this review focuses on the various aspects of pancreatic adult/stem progenitors, CSC hypothesis, its markers, pathways, niche, EMT and novel therapeutic drugs used for the elimination of pancreatic CSCs.