Bone marrow fibroblastic progenitors in patients with advanced breast cancer

Mesenchymal stromal cells, colony-forming unit fibroblasts, from bone marrow of untreated advanced breast and lung cancer patients suppress fibroblast colony formation from healthy marrow

We have shown that bone marrow (BM) from untreated advanced lung and breast cancer patients (LCP and BCP) have a reduced number of colony-forming unit fibroblasts (CFU-Fs) or mesenchymal stem cells (MSCs). Factors that regulate the proliferation and differentiation of CFU-F are produced by the patients' BM microenvironment. We have now examined whether conditioned media (CM) from patients' CFU-F-derived stromal cells also inhibits the colony-forming efficiency (CFE) of CFU-F in primary cultures from healthy volunteers (HV)-BM. Thus the number and proliferation potential of HV-CFU-F were also found to be decreased and similar to colony numbers and colony size of patients' CFU-F. Stromal cells from both of these types of colonies appeared relatively larger and lacked the characteristic spindle morphology typically seen in healthy stromal cells. We developed an arbitrary mesenchymal stromal cell maturational index by taking three measures consisting of stromal cell surface area, longitudinal and horizontal axis. All stromal indices derived from HV-CFU-F grown in patients' CM were similar to those from stromal elements derived from patients' CFU-F. These indices were markedly higher than stromal indices typical of HV-CFU-F cultured in healthy CM or standard medium [alpha-medium plus 20% heat-inactivated fetal bovine serum (FBS)]. Patients' CM had increased concentrations of the CFU-F inhibitor, GM-CSF, and low levels of bFGF and Dkk-1, strong promoters of self-renewal of MSCs, compared to the levels quantified in CM from HV-CFU-F. Moreover, the majority of patients' MSCs were unresponsive in standard medium and healthy CM to give CFU-F, indicating that the majority of mesenchymal stromal cells from patients' CFU-F are locked in maturational arrest. These results show that alterations of GM-CSF, bFGF, and Dkk-1 are associated with deficient cloning and maturation arrest of CFU-F. Defective autocrine and paracrine mechanisms may be involved in the BM microenvironments of LCP and BCP.

Enumeration of the colony-forming units-fibroblast from mouse and human bone marrow in normal and pathological conditions

Bone marrow stromal cell populations, containing a subset of multipotential skeletal stem cells, are increasingly contemplated for use in tissue engineering and stem cell therapy, whereas their involvement in the pathogenetic mechanisms of skeletal disorders is far less recognized. We compared the concentrations of stromal clonogenic cells, colony forming units-fibroblast (CFU-Fs), in norm and pathology. Initially, culture conditions were optimized by demonstrating that fetal bovine serum heat inactivation could significantly repress colony formation. Using non-heat-inactivated fetal bovine serum, the concentration of CFU-Fs (colony-forming efficiency, CFE) ranged from 3.5 +/- 1.0 to 11.5 +/- 4.0 per 1 x 10(5) nucleated cells in five inbred mouse strains. In four transgenic lines with profound bone involvement, CFE was either significantly reduced or increased compared to wild-type littermates. In normal human donors, CFE decreased slightly with age and averaged 52.2 +/- 4.1 for children and 32.3 +/- 3.0 for adults. CFE was significantly altered in patients with several skeletal, metabolic, and hematological disorders: reduced in congenital generalized lipodystrophy, achondroplasia (SADDAN), pseudoachondroplasia, and Paget disease of bone and elevated in alcaptonuria and sickle cell anemia. Our findings indicate that under appropriate culture conditions, CFE values may provide useful insights into bone/bone marrow pathophysiology.

Roles of epidermal growth factor family in the regulation of postnatal somatic growth

Ligands of the epidermal growth factor receptor (EGF-R), known to be important for supporting tissue development particularly in the gut and brain, have also been implicated in regulating postnatal somatic growth. Although optimal levels of both milk-borne and endogenous EGF-R ligands are important for supporting postnatal somatic growth through regulating gastrointestinal growth and maturation, supraphysiological levels of EGF-R ligands can cause retarded and disproportionate growth and alter body composition because they can increase growth of epithelial tissues but decrease masses of muscle, fat, and bone. Apart from their indirect roles in influencing growth, possibly via regulating levels of IGF-I and IGF binding proteins, EGF-R ligands can regulate bone growth and modeling directly because they can enhance proliferation but suppress maturation of growth plate chondrocytes (for building a calcified cartilage scaffold for bone deposition), stimulate proliferation but inhibit differentiation of osteoblasts (for depositing bone matrix), and promote formation and function of osteoclasts (for resorption of calcified cartilage or bone). In addition, EGF-like ligands, particularly amphiregulin, can be strongly regulated by PTH, an important regulatory factor in bone modeling and remodeling. Finally, EGF-R ligands can regulate bone homeostasis by regulating a pool of progenitor cells in the bone marrow through promoting proliferation but suppressing differentiation of bone marrow mesenchymal stem cells.

Alteration on the expression of IL-1, PDGF, TGF-beta, EGF, and FGF receptors and c-Fos and c-Myc proteins in bone marrow mesenchymal stroma cells from advanced untreated lung and breast cancer patients

Previously, we reported a deficient cloning capacity of the bone marrow (BM) mesenchymal stem cells to give colony-forming unit fibroblast (CFU-F) and an inefficient confluence capacity of BM stromal cells in advanced untreated lung cancer patients (LCP) and breast cancer patients (BCP). Moreover, a decreased level of bFGF at day 7 in the conditioned media from BM CFU-F cultures was found in both cancer groups when compared to the normal range. The current study was specially undertaken, to evaluate the percentage of subconfluent fibroblasts expressing receptors (R) of interleukin-1 (IL-1), platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), transforming growth factor (TGF-beta), epidermal growth factor (EGF), and the proteins c-Fos and c-Myc in BM primary cultures from untreated LCP and BCP. An immunocytochemical study on subconfluent BM fibroblast cultures from 13 healthy patients, 16 LCP, and 8 BCP was performed, using as primary antibodies, anti-type I of IL-1 R (IL-1R-1), anti-alpha, beta chains of PDGF R (PDGFR-alpha, PDGFR-beta), anti-type I of FGF R (FGFR-I), anti-type I, II, and III of TGF-beta R (TGF-betaR-I, TGF- betaR-II, and TGF-betaR-III), anti-EGF R, anti-c-Fos, and anti-c-Myc. A diminished percentage of subconfluent fibroblasts expressing PDGFR-alpha, TGFbetaR-I, II, III, EGFR, and FGFR-I was found in LCP and BCP compared to healthy patients. A diminished percentage of subconfluent fibroblasts expressing c-Fos and c-Myc was found in patients when compared to healthy patients. The alterations we describe could help to explain the deficiency regarding the proliferative and confluence capacity of BM stroma cells in cancer patients.