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Nonhematopoietic malignant cells may express receptors for hematopoietic growth factors and respond to these peptides. The aim of the present study was to investigate whether small cell lung cancer (SCLC) cells may be stimulated to proliferate by hematopoietic growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), which are currently used in clinical trials in combination with cytotoxic chemotherapy. We studied two SCLC cell lines, H69 and N417. The effects of GM-CSF and IL-3 were evaluated by studying clonal growth, 3H-thymidine incorporation, BUDR/DNA bivariate flow cytometry, c-myc and N-myc oncogene expression, and myeloid surface markers. Our experiments show that both GM-CSF and IL-3 can increase 3H-thymidine incorporation and cloning efficiency and reduce DNA synthesis time of H69 and, to a lesser extent, N417 cells, supporting the hypothesis that hematopoietic growth factors can stimulate the growth of some malignant nonhematopoietic cells in vitro. Further in vitro and in vivo studies are needed to determine whether clinical trials applying these factors for bone marrow recovery after chemotherapy of solid tumors may be hazardous by potentially stimulating growth of remaining tumor tissue.

Recovery of total T cell numbers after in vivo T-cell depletion in humans is accompanied by complex perturbation within the CD8+ subset. We aimed to elucidate the reconstitution of CD8+ T cells by separate analysis of putative naive CD95− CD28+, memory CD95+ CD28+ and CD28− T cell compartments after acute maximal depletion by high-dose chemotherapy (HD-ChT) in women with high-risk breast cancer. We found that recovery of putative naive CD8+ CD95− CD28+ and CD4+ CD95− CD28+ T cells, was compatible with a thymus-dependent regenerative pathway since their recovery was slow and time-dependent, their values were tightly related to each other, and their reconstitution patterns were inversely related to age. By analysing non-naive T cells, a striking diversion between putative memory T cells and CD28− T cells was found. These latter increased early well beyond normal values, thus playing a pivotal role in total T-cell homeostasis, and contributed to reduce the CD4 : CD8 ratio. In contrast, putative memory T cells returned to values not significantly different from those seen in patients at diagnosis, indicating that this compartment may recover after HD-ChT. At 3–5 years after treatment, naive T cells persisted at low levels, with expansion of CD28− T cells, suggesting that such alterations may extend further. These findings indicate that CD28− T cells were responsible for ‘blind’ T-cell homeostasis, but support the notion that memory and naive T cells are regulated separately. Given their distinct dynamics, quantitative evaluation of T-cell pools in patients undergoing chemotherapy should take into account separate analysis of naive, memory and CD28− T cells.

Hematopoietic growth factors (HGFs) are glycoproteins that control hemopoiesis. They have potential usefulness in a range of clinical conditions including the treatment of patients with myelosuppression induced by chemotherapy. Among HGFs, Stem Cell Factor (SCF) and Interleukin 6 (IL-6) are attracting interest for their capacity to stimulate early hematopoietic progenitors. Furthermore, their use in combination with late-acting growth factors with a more lineage-restricted potential (such as granulocyte colony-stimulating factor, G-CSF) might be expected to offer optimal marrow stimulation and usefulness in clinical oncology. Since non-hematopoietic malignant cells may express receptors for HGFs and respond to these peptides in vitro, we investigated clonal growth 3H-thymidine incorporation and cell cycle analysis by flow cytometry of 5 human solid tumor cell lines under the influence of SCF and IL-6 with or without G-CSF. Our experiments show that these cytokines have no effects on the proliferative capacity of the cell lines tested. Based on our and previously reported data, the use of these HGFs can be considered safe in cancer patients.

An MCF-7 human breast cancer line variant (MCF-7/MPA), resistant to medroxyprogesterone-acetate (MPA), was obtained by continuous exposure in vitro to the drug. MCF-7/MPA cells were grown in the presence of 12.5 x 10(-6) M MPA and were selected by increasing the concentration of the drug in the growth medium in a stepwise manner from 0.025 x 10(-6) M up to 12.5 x 10(-6) M. Comparative studies of cellular morphology, cytosolic steroid receptor content and P-Glycoprotein expression were performed on both MCF-7 parental line and MCF-7/MPA variant. MCF-7/MPA cells, when compared to the parental line, exhibit a different morphology in terms of membrane alterations, reduced content of cytosolic progesterone receptor, increased expression of P-glycoprotein along with reduction of Doxorubicin (Dx) activity on the growth of MCF-7/MPA resistant cells.

Several clinical studies have shown that recombinant human erythropoietin (rHuEpo) can ameliorate the anemia associated with hematologic malignancies and solid tumors. On the other hand, only a few studies have been performed to investigate whether rHuEpo can affect or modulate the growth of malignant cells.We studied the effects of rHuEpo (0.5 to 10 IU/mL) on clonogenic growth and cell kinetics in ten cell lines derived from both hematologic malignancies and solid tumors. Clonogenic assays were performed by plating 5 x 10(3) cells in agar, while the percentage of cells in S phase was assessed by DNA flow cytometry.rHuEpo did not affect either in vitro colony formation or S phase percentage in the human erythroid cell lines K-562 and HEL expressing erythropoietin receptors (40 receptors per cell). No effect of rHuEpo was observed in the remaining hematopoietic cell lines or in five solid tumor cell lines.These findings indicate that rHuEpo, even at very high concentrations, does not affect either clonogenic growth or DNA synthesis in the cell lines tested. Available evidence suggests that rHuEpo can be safely employed in all malignancies except acute myeloid leukemia.

We established and characterized two cell lines derived from glioblastoma multiforme. Both cell lines exhibited tumor cell morphology and growth kinetics and showed variable expression of glial fibrillary acidic protein (GFAP), S-100, fibronectin and vimentin. Cytofluorimetrical analysis of tumor samples showed a diploid DNA distribution, whereas permanent culture cells evolved to the hyperdiploid DNA content. Karyotype studies revealed cytogenetical abnormalities described in glial tumors including gain of chromosome 7, loss of chromosome 10 and presence of double minutes (DMs). Enhanced expression of Ha-ras and c-myc genes resulted from high p-21 and p-62 levels. The contemporary presence of TGF-alpha and EGF-Rc transcripts suggested an autocrine mechanism in the cell lines growth.

✓ Tissue samples from 57 patients with neuroepithelial tumors (25 glioblastomas, 18 anaplastic astrocytomas, and 14 astrocytomas) were analyzed in order to evaluate the presence of estrogen, progesterone, glucocorticoid, and androgen receptors. Glucocorticoid- and androgen-specific binding proteins were present in 38.6% and 21.6% of the cases, respectively. Only a few tumors showed estrogen or progesterone receptors. A correlation was found between grade of anaplasia, patient's sex and age, and presence of glucocorticoid and androgen receptors. The biological role of these two receptors was investigated in 10 primary cell cultures derived from neuroepithelial tumors. For this purpose, dexamethasone and testosterone were added to culture medium at different concentrations (from 50 to 0.016 µg/ml). A significant stimulation of the cell growth was observed in four of five glucocorticoid receptor-positive cultures when dexamethasone in doses ranging from 2 to 0.016 µg/ml was added to the culture. No modulation of the growth was observed in glucocorticoid receptor-negative cultures at the same doses. Higher dexamethasone doses induced a significant decrease of the growth index independently from the glucocorticoid receptor status. All of the cultures tested for testosterone activity were negative for androgen receptors. This hormone induced an inhibition of the growth index at doses ranging from 50 to 0.4 µg/ml. The data suggest that neuroepithelial tumors contain specific glucocorticoid and androgen binding proteins. Glucocorticoid receptors modulate the growth of cultured neuroepithelial tumors in the presence of different concentrations of dexamethasone.

Tissue samples derived from two neuroepithelial tumours and five meningiomas were obtained at surgery from seven patients and cultured in order to study the effect of dexamethasone (DEX) and testosterone acetate (TA) on cell proliferation. Glucocorticoid and androgen receptors (GR, AR) were determined both on tissue samples (7 cases) and on five out of the seven cell cultures obtained by tumours. GR and AR were present respectively in 5 and in 4 out of the tumour specimens assayed and in 4/5 and 2/3 of the tested cell cultures. DEX activity on cell growth was tested on six cell cultures. Four of them showed a significant growth inhibition at the highest drug concentration. On the contrary, a significant growth stimulation was observed in four out of the five cultures, where GR were present, using low hormone concentrations. Treatment with pharmacological doses of TA caused a significant cytotoxicity in all the tested cultures. Low TA concentrations inhibited cell growth in one out of the two cell cultures which contained AR, but were ineffective in cultures lacking AR. Our preliminary results suggest a possible role in growth regulation by DEX and TA in intracranial tumours, on the basis of the presence of specific hormone receptors.