Sedimentation field flow fractionation monitoring of in vitro enrichment in cancer stem cells by specific serum-free culture medium.

The development of methods to enrich cell populations for cancer stem cells (CSC) is urgently needed to help understand tumor progression, therapeutic escape and to evaluate new drugs, in particular for colorectal cancer (CRC). In this work, we describe the in vitro use of OncoMiD for colon, a CRC-specific primary cell culture medium, to enrich CRC cell lines in CSC. Sedimentation field flow fractionation (SdFFF) was used to monitor the evolution of subpopulations composition. In these models, medium induced a loss of adherence properties associated with a balance between proliferation and apoptosis rates and, more important, an increased expression of relevant CSC markers, leading to specific SdFFF elution profile changes.

P75 neurotrophin receptor is sequestered in the Golgi apparatus of the U-87 MG human glioblastoma cell line.

The P75 neurotrophin receptor (p75NTR) is a cell surface receptor that can induce apoptosis in many cell types. This receptor plays a major role in the development of the central nervous system and is expressed in some adult brain cells. Its implication in cell apoptosis or survival is probably of major importance in cellular homeostasis and thus p75NTR could be implicated in tumor resistance to death. In this study, we investigated the intracellular expression of p75NTR in a human glioblastoma cell line. Detection of p75NTR receptor in Golgi apparatus by immunofluorescence microscopy, or after Golgi apparatus extraction, could be correlated with a decrease of cell apoptosis leading cells to become tumorous. This hypothesis is supported by a loss of ligand-induced apoptosis in this cell line. Our observations show that p75NTR can be sequestered in the Golgi complex and could then be, in part, responsible for the cell resistance to apoptosis and for brain tumor formation.

Oncogramme, a new individualized tumor response testing method: application to colon cancer.

Colon cancer is the second leading cause of cancer-related death in industrialized countries. Many anti-cancer researches are consequently performed and individualized tumor response testing (ITRT) methods are now used to individualize patient chemotherapeutic administrations. Then, a new ITRT method, Oncogramme, was developed for colon cancer. Colon tumor fragments from different patients were dissociated and seeded in a defined culture medium. Cell preparation process as well as culture medium allowed high cell viability and a good primary culture success rate. After treatment of isolated tumoral cells by chemotherapeutics alone or in combination, cytotoxicity was determined by cell death assay allowing the Oncogramme establishment, which was validated by statistical analysis. Indeed, significant results were obtained such as different profile for each patient's cells with various drugs, and variability between patient's cells in the response to each drug. Procedure described here to obtain the Oncogramme is a new, fast and technically reliable ITRT method applied to colon cancer. For an individualized cancer treatment use, this test should be further validated by a phase I clinical trial.