STELLA: a Feasibility Study on Stem Cells Sensitivity Assay

Patients Patients with LC, CRC and BC with good performance status and with tumor tissue available, at failure of conventional therapies or without possibility to be treated with therapy of proven efficacy, will be included in the study. Initial patient characterization will include detailed information on the following items: gender, age, clinical history, co-morbidity, physical examination, blood cell counts, complete blood analyses for liver and renal function, coagulation, serological tumor markers, tumor location and stage, tumor mass, metastases.

LC, CRC and BC CSCs identification Isolation and characterization of CSCs will be made starting from samples of tumor tissue obtained from patients with LC, CRC and BC. Tumor tissue will be collected before study entry, i.e tissue obtained during a diagnostic or therapeutical procedure, like surgery or biopsies with other purposes than the protocol.The surgical samples collected will be classified according to the specific histological characteristics of the tumor. From each sample, by means of enzymatic and mechanical procedures, the CSCs will be obtained and then cultivated in adequate culture mediums to be subsequently used for biochemical and molecular studies. Each sample will be associated with the patient history at the surgical time and an appropriate follow-up program consisting of periodic clinical and instrumental controls that in order to assign a prognostic value to the biological characteristics of the CSCs. Stem cells derived from the selected epithelial tumors will then undergo analysis of surface and intracellular markers in order to provide a definitive characterization of cellular phenotype. Stem cells derived from lung cancer, CRC and BC are identified as a subset of tumor cells positive for the marker CD133.

Tumor specimens will be washed several times and left over night in DMEM:F12 medium supplemented with high doses of Penicillin/Streptomycin and Fungizone in order to avoid contamination. Tissue dissociation will be carried out by enzymatic digestion and recovered cells cultured in serum-free medium containing 25 microg/ml insulin, 100 microg/ml apo-transferrin, 10 microg/ml putrescine, 0.03 mM sodium selenite, 20nM progesterone, 0.6% glucose, 5mM hepes, 0.1% sodium bicarbonate, 0.4% BSA, glutamine and antibiotics, dissolved in DMEM-F12 medium and supplemented with 20 ng/ml EGF and 10 ng/ml bFGF. Flasks non-treated for tissue culture will be used in order to reduce cell adherence and favourite growth of undifferentiated tumour-spheres. These culture conditions select for immature tumour cells, while non malignant or differentiated cells are negatively selected as assessed for CSCs of different origin. Surviving immature tumor cells slowly proliferate giving rise to tumour cell aggregates, "spheres", within 1-2 months in these culture conditions. Sphere-forming cells can be expanded by mechanical dissociation of spheres, followed by re-plating of single cells and residual small cell aggregates in complete fresh medium.

Differentiation of LC, CRC and BC sphere-forming cells will be obtained by cell culture in specific medium (Cambrex). Phenotype of LC, CRC and BC spheres and their differentiated progeny will be analyzed by flow cytometric analysis or immunofluorescence. In particular stem cell markers such as CD133, CD34 and BCRP1 will be analyzed.

Successively, cancer spheres will be analyzed in order to define the status of pathways involved in the process of proliferation, self-renewal and survival. In particular, tumor-specific analysis will be carried out to investigate the activity and the possible alteration of pathways responsible for stem cell homeostasis and global analysis (phosphoproteomic and signal transduction analysis,innovative drug testing, analysis of processes metastatization in vivo) aimed to provide an overall picture of the activation state of the key cellular pathways.