Biomedical subjects

J Titley

Publications and source records attributed to J Titley.

12 recordsLinked to original sources

PubMed1996

Interleukin-4 enhances the survival of severe combined immunodeficient mice engrafted with human B-cell precursor leukemia.

Human interleukin-4 (huIL-4) has been shown to inhibit the growth in vitro of cells from patients with acute lymphoblastic leukemia (ALL). With the aim of determining whether this cytokine might be useful in the treatment of patients with ALL, the effects of huIL-4 on human B-cell precursor ALL engrafted in severe combined immunodeficient (SCID) mice were examined. The inhibition of [3H] thymidine uptake of primary ALL cells by huIL-4 was maintained following engraftment and passage of leukemia in SCID mice. Five of seven xenograft leukemias showed significant inhibition in vitro by huIL-4 at concentrations as low as 0.5 ng/mL; furthermore, huIL-4 counteracted the proliferative effects of IL-7. When used to treat two human leukemias engrafted in SCID mice, huIL-4 200 microgram/kg/d, as a continuous 14-day subcutaneous infusion, suppressed the appearance of circulating lymphoblasts and extended survival of mice by 39% and 108%, respectively, the first demonstration of IL-4 activity against human leukemia in vivo. The mean steady-state huIL-4 level in mouse plasma during the infusion was 1.46 ng/mL (SEM +/- 0.14 ng/mL), which was similar to concentrations found to be effective in vitro. ALL cells obtained from mice relapsing after huIL-4 treatment continued to show inhibition by the cytokine in vitro. These data suggest that IL-4 may be useful in the treatment of patients with ALL.

Animals↗

PubMed1996

Comparison of MIB-1 proliferation index with S-phase fraction in human breast carcinomas.

The MIB-1 antibody has been raised against recombinant parts of the Ki-67 antigen and, unlike Ki-67, has wider application to routinely fixed specimens. The aim of this study was to compare the usefulness of MIB-1 with S-phase fraction (SPF) as a measure of proliferation. A total of 75 patients with operable breast cancer were studied, 44 (median age 56 years) before any treatment and 31 (median age 68 years) after primary medical hormonal therapy. Sections from formalin-fixed paraffin-embedded tissue were stained with the MIB-1 antibody and a percentage score of positively stained cells obtained. SPF was measured by flow cytometry in fine-needle aspiration samples taken from the same lesion in each patient. Median MIB-1 score was 9% and median SPF was 11.1%. A close correlation was found between MIB-1 score and SPF (rho=0.59, P<0.0001). There was a difference in the strength of the correlation found between the no treatment group and the treatment group, however, 95% confidence intervals for the rho values overlapped, indicating that there was no significant statistical difference. When analysed for ploidy status a correlation was found only in aneuploid tumours. MIB-1 immunostaining can be used as an effective method of assessing proliferation in human breast carcinomas. This can be done using simple, widely available technology and provides the opportunity to perform large-scale retrospective analyses of archival materials.

Aged↗

PubMed1996

Application of a bromodeoxyuridine-Hoechst/ethidium bromide technique for the analysis of radiation-induced cell cycle delays in asynchronous cell populations.

A flow cytometric technique utilizing the continuous incorporation of bromodeoxyuridine (BrdU) into asynchronous cells to measure radiation-induced cell cycle delay is described. Following the incorporation of the BrdU label the cells are stained with ethidium bromide and the bis-benzimidazole Hoechst 33258. These fluorochromes have differential staining patterns. Hoechst 33258 fluoresces blue and is quenched by BrdU incorporated into cellular DNA during S phase. Ethidium bromide fluoresces red and is not quenched by BrdU. Therefore in cells that are cycling and synthesizing DNA new G1 and G2 compartments are created and this can be used to measure cell cycle delays following ionizing radiation to asynchronous cells. We have used this technique to evaluate two cell lines: a normal diploid human embryo fibroblast cell line MRC 5, which has inducible p53 and shows delays at both G1 and G2 checkpoints, and the human cervix carcinoma cell line HX 156. This cell line has been infected with human papilloma virus (HPV) 16, and therefore has inactivated p53 function and is blocked only at the G2 checkpoint. Using this method, cell cycle-dependent effects relating to the G2 block can be observed. The radiation-induced G2 block differs from that induced by drugs or heating in that cells are blocked in G2 irrespective of the phase of the cell cycle they are treated in. This method allows these different types of G2 block to be quantified.

Bisbenzimidazole↗

PubMed1995

Determining factors which predict response to primary medical therapy in breast cancer using a single fine needle aspirate with immunocytochemical staining and flow cytometry.

The increasing use of neoadjuvant chemotherapy and endocrine therapy in the management of breast cancer has lead us to evaluate and optimise the standard technique of cytocentrifugation of a single fine needle aspirate (FNA) taken from a breast tumour in-vivo, to determine a range of both immunocytochemical and flow cytometric factors which are predictive of response to primary medical therapy. Some of these factors are also of prognostic significance in early stage disease. An analysis of the cellularity and immunocytochemical staining characteristics of FNAs obtained from a series of 206 patients with palpable breast cancers indicate that in a sample of 46 cases it is possible to measure oestrogen receptor, progesterone receptor and c-erbB-2 providing over 400 cells per slide are obtained, with material obtained in a single FNA prepared by cytocentrifugation, using standard immunocytochemical methods. The staining results obtained were comparable to those obtained using frozen or paraffin embedded tissue sections taken from the same tumour. In addition an estimate of the proliferation indices could be made by flow cytometric analysis of the residual cell suspension fluid with measurement of DNA index and S-phase fraction in 131/164 (80%) and 110/164 (67%) of cases respectively. Providing all FNAs obtained for cytocentrifugation were taken at first presentation rather than immediately following a standard FNA, then it was possible to obtain adequately cellular (> 400 cells/slide) samples in 96 out of 126 (75%) of the last cohort of breast aspirates. These effects may be independent of T stage but not histological type as patients with lobular tumours only produced cellular aspirates in 1/7 (14%) of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy, Needle↗

PubMed1995

Programmed cell death in response to chemotherapeutic agents in human germ cell tumour lines.

Testicular germ cell tumours are amongst the most chemosensitive neoplasms both in vivo and in vitro. In the present study we demonstrate that following exposure to drugs used in chemotherapeutic treatment of testicular germ cell cancer tumour cells undergo death by apoptosis. Thus, after exposure of the GCT27 embryonal carcinoma cell line to cisplatin, we observed the degradation of DNA into oligonucleosomal fragments, which is a hallmark of apoptosis. Furthermore, light, fluorescence and electron microscopy reveal the presence of condensed abnormal shaped nuclear chromatin which is characteristic of apoptosis. Changes diagnostic of apoptosis were also observed following (a) cisplatin treatment of the GCT48 and Susa embryonal carcinoma cell lines and the GCT44 yolk sac tumour cell line and (b) etoposide treatment of the GCT27 and Susa cell lines. When the GCT27 cell line was treated with 15 microns cisplatin, apoptosis was first observed at 6-9 h and greater than 90% of cells were dead within 24 h. Apoptosis was not blocked when cisplatin-treated cells were incubated in the presence of cycloheximide, although this agent did cause a 4-6 h delay in the onset of cell death. In addition, we demonstrated that the GCT27 cell line can be induced to undergo apoptosis by exposure to low concentrations of the calcium ionophore, ionomycin. These observations show that germ cell tumours are remarkably sensitive to a range of agents that act by different mechanisms. They are triggered to undergo apoptosis rapidly by a mechanism that is not blocked by inhibitors of protein synthesis.

Apoptosis↗

PubMed1994

Differentiation or immune destruction: two pathways for therapy of squamous cell carcinomas with antibodies to the epidermal growth factor receptor.

We have carried out an immunohistochemical investigation of xenografts of epidermal growth factor receptor (EGFR)-overexpressing tumors that have been induced to regress by treatment with rat monoclonal antibodies (mAbs) to the human EGFR [ICR16 (IgG2a), ICR62 (IgG2b), and ICR64 (IgG1)]. When mice bearing xenografts of the HN5 squamous cell carcinoma were treated for 5 days with mAb ICR62 or ICR16, the antibodies were found to be localized uniformly on the tumor cell membranes. However, the foci of tumor cells that remained following treatment with ICR62 were smaller than with ICR16 and the former showed a more pronounced host mononuclear cell infiltrate. Examination of the few tumors that had not regressed completely and were still present as static nodules 77 days following the final treatment with anti-EGFR mAbs revealed significant levels of therapeutic mAb in the nonviable areas of the tumors. The microscopic areas of apparently viable tumor cells that did not stain when only secondary antibody was used stained positive when the sections were treated first with an anti-EGFR antibody. This suggests that loss of the target antigen was not a significant factor and that these residual cells might be eradicated by further treatment with mAb. Furthermore, the finding of keratinized areas in the tumors undergoing regression suggested that the carcinoma cells had undergone terminal differentiation following exposure to antibody. This possibility was supported by the finding that treatment of HN5 cells in vitro with mAbs ICR16, ICR62, or ICR64 resulted in the accumulation of cells in the G0-G1 phases of the cell cycle and expression of the terminal differentiation markers involucrin and cytokeratin 10. We found no evidence of apoptosis in such cells. We conclude that antibodies which block the binding of EGF and transforming growth factor alpha to the EGFR can inhibit the growth of EGFR-overexpressing tumors by directing terminal differentiation and that a further therapeutic benefit may be obtained via immunological mechanisms with rat IgG2b mAbs such as ICR62.

Animals↗

PubMed1994

Ectoenzyme regulation by phenotypically distinct fibroblast sub-populations isolated from the human mammary gland.

Inter- and intralobular mammary fibroblasts have been separated from normal human breast tissue and cultured to study the differential expression of ectoenzymes present within the stroma of the normal gland and associated with breast cancers. Specific ectoenzymes were identified by indirect immunofluorescence and quantified by flow cytometry and semi-quantitative PCR. A consistent difference was noted between the two fibroblast sub-populations at early passage in respect of dipeptidyl peptidase IV (DPP IV) and aminopeptidase N (APN) expression. Early passage intralobular fibroblasts were positive for APN but negative for DPP IV, as seen in the intact tissue. However, with continued sub-culture they gradually began to express DPP IV, until at later passages they became indistinguishable from the interlobular fibroblasts, which were APN and DPP IV-positive at all stages in culture, as they are in intact tissue. Neutral endopeptidase (NEP/CALLA/CD10) is not expressed by normal adult breast fibroblasts but is found in the stroma associated with over 60% of breast cancers. It was up-regulated in vitro on both inter- and intralobular fibroblasts, with final levels that were significantly (< 14 times) higher on the former in all pairs of preparations from individual donors analysed. This difference persisted with continued passage, and levels of the ectoenzyme and its messenger RNA were further up-regulated by hydrocortisone in both populations. These results demonstrate that phenotypically distinct cultures of human mammary fibroblast sub-populations can be used to study the regulation of these stromal ectoenzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Growth of primary human acute lymphoblastic and myeloblastic leukemia in SCID mice.

The in vivo growth of 8 human primary acute lymphoblastic (ALL) and 17 primary acute myeloblastic (AML) cell populations was investigated in severe combined immunodeficient (SCID) mice. Bone marrow (BM) or peripheral blood (PB) samples, either fresh or cryopreserved, were implanted i.v. into irradiated SCID mice. The cells from 5/8 patients with ALL resulted in engraftment with systemic proliferation and dissemination leading to morbidity and mortality of the animals within 12-18 weeks from implantation. In contrast, none of the 17 AML samples resulted in sustained engraftment. Four of the 5 engrafted ALL populations have been successfully passaged into fresh recipients and phenotypic and karyotypic characteristics remain unaltered. The data presented indicate that the SCID mouse may be a useful model for studying the pathogenesis of ALL and may also enable the development and investigation of new therapies for this disease.

Adult↗

PubMed1994

An immunomagnetic separation method using superparamagnetic (MACS) beads for large-scale purification of human mammary luminal and myoepithelial cells.

A comparison has been made between different immunomagnetic techniques for separating normal human mammary epithelial cells based on the exclusive expression of EMA (epithelial membrane antigen) by luminal cells and CALLA (CD10) by myoepithelial cells. When cells labelled with antibodies to these antigens were incubated with Dynabeads, they rosetted myoepithelial but not luminal cells. However, both luminal and myoepithelial cells could be positively separated using the MACS system. Purity was established by analyzing the expression of CALLA and EMA using flow cytometry, and of cell-type specific cytokeratins using indirect immunofluorescence. Dynabead-separated myoepithelial cell populations were of high purity (> 98%) but the beads could not be removed from the cells. Luminal cell populations separated by the MACS method were also highly purified (> 95%), as were myoepithelial cell populations (> 90%). Using this immunomagnetic separation method, up to 10(7) cells of each type could be obtained from individual preparations.

Adolescent↗

PubMed1993

Cell-cycle progression during continuous low dose rate irradiation of a human bladder carcinoma cell line.

At very low radiation dose rates, the proliferation of mammalian cells continues unaffected but as the dose rate is increased there comes a point at which it is interrupted. The dose rate at which this happens is often thought to be a significant factor in the effects of brachytherapy: it may determine the range from an implanted source at which cell-cycle redistribution and repopulation effects will occur. By means of mitotic counts and DNA flow cytometry, we have examined the dose rate effect in a human bladder carcinoma cell line (MGH-U1). Irradiation at dose rate 0.1 cGy/min had little or no effect on cell-cycle progression. Suppression of mitosis and arrest of cells in G2 was observed at 0.4 cGy/min and above. Surprisingly, the duration of mitotic arrest showed little dose rate dependence; it was followed by an overshoot of cells in mitosis after 24-39 h of irradiation. An even more pronounced overshoot of cells in G2 occurred and persisted throughout the irradiation period. The cell kinetic data indicate that after the temporary block in cell-cycle progression, cell proliferation continued at all dose rates up to 1.4 cGy/min. We have evaluated these results in the light of previous studies in this department of the dose rate effect for cell survival in the MGH-U1 cell line. After 24 h irradiation at 1.4 cGy/min the surviving fraction was below 10(-2), also after 30 h at 1.0 cGy/min. When cell-cycle blockade is considerable, so is the level of cell killing. Flow-cytometric data therefore are dominated by the properties of cells that are doomed to die.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Cycle↗

PubMed1993

DNA ploidy in early gastric carcinoma (T1): a flow cytometric study of 100 European cases.

DNA ploidy of 100 early gastric carcinomas (T1) was analysed by flow cytometry on archival material from five European centres and was correlated to morphological features and clinical behaviour. Tumours were classified according to the macroscopic appearance, histological type, and growth pattern. Aneuploidy was observed in 39% of tumours. Aneuploidy was more frequent in submucosal than in mucosal tumours (p = 0.04), in raised than in flat or ulcerated lesions (p = 0.001), and in the intestinal histological than in the diffuse types (p = 0.016). The presence of lymph node metastasis in 10 cases had no obvious relation to DNA ploidy. Five related deaths occurred during the follow up (6 months--16 years) of 84 patients. These results are similar to those reported in a large Japanese series suggesting no major differences between the two populations. Although follow up data were insufficient to relate DNA ploidy to tumour behaviour in this study, the Japanese experience shows that particular attention should be paid to early direction and complete surgical excision of raised intestinal type T1 carcinomas that have a Pen A growth pattern and are aneuploid.

Adult↗

PubMed1991

Growth of primary human acute leukemia in severe combined immunodeficient mice.

Seven populations of human leukaemic cells were implanted i.v. into sublethally irradiated severe combined immunodeficient (scid) mice. Growth of leukaemia was monitored by labelling murine peripheral blood (PB) cells with an anti-HLA monoclonal antibody and flow cytometric analysis. Two of the populations transplanted were fresh acute lymphoblastic leukaemia (ALL) bone marrow (BM) cells which both caused sustained proliferative growth in scid mice. Human cells accounted for up to a mean of 87% of the total nucleated cells (TNC) in the PB of these mice between weeks 12-15. One of these populations was passaged into fresh mice and frank leukaemia was again established. Three populations of cryopreserved acute myeloblastic leukaemia (AML) cells (2 obtained from PB and 1 from BM) and one population of cryopreserved biphenotypic acute leukaemia BM cells, only grew to a maximum of 4% within the 15 week period of the experiment. A cell population from an AML cell line (HL60), however, did engraft and proliferate resulting in a rapid deterioration of these mice between weeks 3-6 when the proportion of human cells accounted for 9% of the TNC in the PB.

Acute Disease↗