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R C Coombes

Publications and source records attributed to R C Coombes.

At least 91 records · Page 5Linked to original sources
PubMed1995

Expression of 2 variant forms of fibroblast growth factor receptor 1 in human breast.

The expression of variant mRNAs encoding isoforms of fibroblast growth factor receptor (FGFR)1 with either 2 or 3 Ig-like loops in the extracellular domain was investigated in human breast tissues and cell lines using a polymerase chain reaction amplification method. Almost all tissues contained both forms of FGFR1, but cancers (n = 137) had a significantly lower proportion of the transcript that encoded the full 3-loop form compared with non-malignant biopsies (n = 34). This was confirmed using microdissected populations of normal and cancerous cells from frozen tissue sections. A high ratio of the 2- to 3-loop form was found to be predictive of reduced relapse-free survival. In both groups, however, the predominant form of FGFR1 was that encoding the 2-loop receptor. Cell lines derived from a variety of tissues, including breast, also co-expressed both variants of FGFR1, suggesting their presence within the same cell type. Again, there was a similar preponderance of the shorter isoform. Our results were confirmed at the protein level, where out of 5 cancers analysed 4 expressed more of the 2-loop form than the 3-loop form. Our findings suggest that cells may normally simultaneously express several splice variants of FGFR1, and aberrant expression or a change in their relative amounts (i.e., in malignancy) could contribute to modified responses to either autocrine or paracrine factors.

Adult↗
PubMed1995

Isolation of pure populations of epithelial and myoepithelial cells from the normal human mammary gland using immunomagnetic separation with Dynabeads.

Monoclonal antibodies to epithelial membrane antigen and common acute lymphoblastic leukemia antigen were bound to second antibody-coated magnetic microspheres. These specific antibody/bead complexes were then used to directly isolate purified epithelial and myoepithelial cells from normal breast organoid cell preparations by magnetic separation. Near homogeneous cell populations were selected with yields of 10-20 x 10(6) epithelial and myoepithelial cells per organoid preparation. Repeated purification steps allowed almost complete depletion of myoepithelial cells for RNA studies. Tissue culture of separated cell populations in appropriate defined media further ensured purity of cell type and was unimpeded by Dynabead attachment.

Antibodies, Monoclonal↗
PubMed1995

bFGF and aFGF induce membrane ruffling in breast cancer cells but not in normal breast epithelial cells: FGFR-4 involvement.

Acidic and basic fibroblast growth factors (aFGF and bFGF) are growth factors which may have a physiological role in the normal breast and in breast cancer. A study of the effects of aFGF and bFGF on a variety of breast cell lines and epithelial cells purified from normal breast organoids showed that whereas normal breast cells did not exhibit membrane ruffling in response to either of these growth factors, some breast cancer cell lines did. This difference was not due to lack of receptor since all the cell lines tested were mitogenically stimulated by bFGF. Dominant negative mutations of FGF receptor 3 (FGFR-3) and the small GTP-binding protein p21rac inhibited membrane ruffling, showing that receptor dimerization and phosphorylation and p21rac activation are prerequisites for membrane ruffling in response to aFGF and bFGF. Transient transfection of individual FGFRs into cos-7 cells showed that FGFR-1, FGFR-2 and FGFR-3 could not mediate a membrane ruffling response whereas FGFR-4 could. These studies elucidate one signalling mechanism of FGF and point to differences in the response of normal and cancer breast epithelial cells which may be important in cell motility.

3T3 Cells↗
PubMed1995

Idoxifene: report of a phase I study in patients with metastatic breast cancer.

Idoxifene, a novel antiestrogen with reduced estrogenic activity when compared to tamoxifen, has been given to 20 women with metastatic breast cancer, 19 of whom had received tamoxifen previously, in doses between 10-60 mg. Idoxifene had an initial half-life of 15 h and a terminal half-life of 23.3 days. At a maintenance dose of 20 mg, a mean steady-state level of 173.5 ng/ml was achieved. Significant falls in luteinizing hormone and follicle-stimulating hormone were seen, but the falls were not dose related. Idoxifene was well tolerated, with 11 patients complaining of mild symptoms similar to those seen with tamoxifen. Fourteen patients continued idoxifene therapy for 1-56 weeks; 4 patients showed stabilization of disease for 6-56 weeks and 2 patients showed a partial response.

Adult↗
PubMed1995

Expression of fibroblast growth factor 1 is lower in breast cancer than in the normal human breast.

We have measured the amount of fibroblast growth factor 1 (FGF-1) mRNA and protein in primary breast cancers and non-malignant breast tissue and have found greatly reduced levels in breast cancer compared with non-malignant tissue. A total of 116 breast cancers and 37 biopsies taken from non-malignant breast were compared for FGF-1 mRNA expression using reverse transcriptase-polymerase chain reaction (RT-PCR) and significantly lower levels were found in the cancer tissues (P < 0.001). These findings were confirmed at the protein level where four out of five breast cancers contained no detectable FGF-1 and a fifth cancer had a low level of FGF-1 compared with three samples from reduction mammoplasties. Similar results were obtained from breast cell lines in which 80% of cancer cell lines had very low levels of FGF-1, whereas all non-malignant breast cell lines contained higher levels of FGF-1. Immunohistochemical analysis indicated that FGF-1 was present in the luminal epithelial cells of the non-malignant breast but was absent from cancer cells. The decreased levels of FGF-1 in breast cancer may indicate that stimulation of cancer cells is resulting in down-regulation of FGF-1 expression or may implicate FGF-1 as a differentiation factor rather than a growth factor at its physiological concentration in the breast.

Adult↗
PubMed1994

Detection of breast cancer micrometastases in axillary lymph nodes by using polymerase chain reaction.

Breast cancer micrometastases in axillary lymph nodes have been detected by serial sectioning and immunohistochemistry, and shown to have prognostic significance. We have used polymerase chain reaction (PCR) to see whether we could further improve the detection rate of micrometastases. Fifty-seven axillary lymph nodes from patients with breast cancer were examined histologically to assess the proportion of tumor involvement. Immunohistochemical staining with the use of an anti-keratin 19 antibody confirmed the histological findings. Reverse transcription PCR was then performed on extracted RNA by using K19 primers, and all 18 histologically involved nodes yielded the expected 460-base pair product. Of 39 histologically negative nodes, 4 (10%) gave K19 bands detectable with ethidium staining and a further 10 (28%) gave K19 bands after Southern hybridization. To further increase the detection sensitivity a two stage amplification was performed by using nested primers, and K19 product was found in lymph nodes from patients without cancer, as well as in all the nodes from cancer patients. This was shown to be genuine low level expression from endogenous mRNA template, and not derived from amplification of a K19 pseudogene. Reducing the number of PCR cycles in the two amplification steps did not allow sufficient discrimination between normal nodes and those involved nodes in which K19 expression was only detectable after Southern hybridization. The optimal "cut-off" point to distinguish involved nodes from normal nodes remained at the level of 40 cycles of PCR and Southern hybridization. PCR, using K19 as a tumor marker, has been demonstrated in this study to improve the detection of micrometastases in axillary lymph nodes in patients with breast cancer: sensitivity is limited by the specificity of the tumor marker.

Adult↗
PubMed1994

Second generation aromatase inhibitor--4-hydroxyandrostenedione.

4-hydroxyandrostenedione is a steroidal, suicide substrate inhibitor of aromatase, which has been widely tested in postmenopausal breast cancer patients. It is highly specific with the only notable endocrine changes other than oestrogen suppression being a dose-related suppression of sex-hormone binding globulin when the drug is given orally (a reflection of the drug's minor androgenic activity). Intramuscular administration of 250 mg every second week is the schedule of choice. This achieves peripheral aromatase inhibition of about 85% and oestradiol suppression of about 65%. The drug is usually used second-line, after tamoxifen, with an overall response rate in unselected patients of 26%. Side-effects are minimal and consist almost entirely of local reactions at the site of injection. 4-hydroxyandrostenedione is therefore a useful new treatment option as the first selective aromatase inhibitor to have wide clinical availability.

Administration, Oral↗
PubMed1994

Endocrine changes with the aromatase inhibitor fadrozole hydrochloride in breast cancer.

Fadrozole hydrochloride is a potent aromatase inhibitor with proven clinical effectiveness. However, its optimal dose and its effects on serum aldosterone levels/electrolyte balance have been disputed. To resolve these issues, a double-blind randomised endocrine study of three doses of fadrozole hydrochloride [0.5 mg twice daily (bd); 1.0 mg bd; 2.0 mg bd] was conducted in 80 (68 evaluable) postmenopausal patients with advanced breast cancer over a period of 3 months. There were substantial falls in the serum levels of oestradiol, oestrone and oestrone sulphate. For oestrone only, there was a significant effect of dose (on-treatment means: 0.5 mg, 38.0 pmol/l; 1.0 mg, 25.0 pmol/l; 2.0 mg, 23.9 pmol/l). All oestrogens showed a similar pattern in relation to time, with the 3-month mean being higher than those at 1 and 2 months, and this was significant for oestradiol (P = 0.012). There was an indication that complete suppression of oestradiol and oestrone was not maintained throughout the 12-h dosing period, but the data and its interpretation are complicated by a minor diurnal rhythm in these parameters. There were significant increases in 17-hydroxyprogesterone and androstenedione which may be due to a block of 11 beta-hydroxylase. There was a statistically non-significant fall in aldosterone levels (P = 0.06) during treatment (median pretreatment, 446 pmol/l; median decrease, 125 pmol/l). However, the concurrent significant fall in the plasma sodium: potassium ratio indicated that changes in aldosterone secretion did occur. None of these effects on adrenal pathways was of a degree which is likely to have clinically relevant consequences. It is concluded that fadrozole hydrochloride achieves near maximal suppression of oestrogens at 1 mg bd, and that its effects on aldosterone synthesis are unlikely to be of clinical significance.

Adult↗
PubMed1994

The effect of endocrine therapy on the levels of oestrogen and progesterone receptor and transforming growth factor-beta 1 in metastatic human breast cancer: an immunocytochemical study.

The levels of oestrogen receptor (ER), progesterone receptor (PR) and transforming growth factor-beta 1 (TGF-beta 1) were measured by immunocytochemistry in 19 patients prior to and 1 month after the start of endocrine therapy (tamoxifen 10 patients; aromatase inhibition 9 patients). A complete or partial response was observed in 10 patients. The proportion of cells showing ER staining was higher in responding patients, but there was no change observed with endocrine therapy in either responding or non-responding patients. In contrast, cells staining for PR in responding patients were significantly reduced following therapy (59 +/- 9% to 24 +/- 9%: P < 0.05). There was no reduction in immunocytochemical PR in non-responding patients, although the numbers of these patients with initially positive PR levels was small. Stromal tissue adjacent to tumour cells stained with the antibody to TGF-beta 1, with particularly intense staining at the periphery of tumour cell aggregates. There was no correlation between the degree of TGF-beta 1 staining and ER or PR status, and no evidence of a change with endocrine therapy. It is concluded that neither tamoxifen nor aromatase inhibitors produce a change in the ER content or TGF-beta 1 content of breast tumours as detected immunocytochemically, but PR levels are significantly reduced after therapy in responding patients.

Adult↗
PubMed1994

Acidic and basic fibroblast growth factors in human breast tissue.

Previously we have reported changes in fibroblast growth factors (FGF) in conditioned medium (CM) derived from rat mammary tumours undergoing remission. We have used a similar approach to assay for the presence of FGFs in human breast tissue and cell lines. The majority of cancer tissues (35/50), benign tissues (8/9) and all cancer adjacent normal tissues (20/20) released heat labile, NR6 transforming activity which coeluted from heparin with acidic FGF (aFGF) at 0.9-1.1 M NaCl and was neutralised by antibodies to aFGF. The conclusion that the majority of breast cancers contain active aFGF was supported by immunoblotting. The CM of a minority (15/50) of cancers and one benign tissue had highly transforming activity for NR6 cells, and was mitogenic for a breast cancer cell line, was heat labile, and strongly heparin binding, eluting at 1.5-2.0 M salt. It was not immunoreactive with antibodies to aFGF, basic FGF (bFGF) or Kaposi's FGF (kFGF) and its activity was reduced by the presence of aFGF, suggesting competition for the same receptor. Very little aFGF was observed in the CM of these tumours, and neither aFGF nor other FGF activity was detected in CM of breast cell lines.

Breast↗
PubMed1994

Lack of inhibition of placental estrone sulfatase and aromatase enzymes by vitamin D3 and its analogs.

The aromatase and estrone sulfatase enzymes are important sources of biologically active estrogens in postmenopausal women with breast cancer. Promising initial results in the treatment of endocrine-responsive breast cancer have been exhibited by 1 alpha 25-dihydroxyvitamin D3 and the synthetic vitamin D analogues MC903 and EB1089. However, these compounds together with vitamin D3 and vitamin D3 sulfate did not inhibit the human placental aromatase enzyme when assayed up to 20 microns. Only vitamin D3 sulfate and 1 alpha 25-dihydroxyvitamin D inhibited the estrone sulfatase activity in human placental microsomes, albeit at high concentration (32 and 37% inhibition, respectively with 50 microns each inhibitor). It is unlikely that inhibition of aromatase or estrone sulfatase enzymes contribute to the inhibitory effect of this group of compounds on breast cancer cells in vivo.

Aromatase Inhibitors↗
PubMed1994

Intratumoral oestrone sulphatase activity as a prognostic marker in human breast carcinoma.

Oestrone sulphatase is an important source of local synthesis of biologically active oestrogens in human breast cancer. The oestrone sulphatase enzyme in the particulate fraction of human breast carcinoma was characterised. The Km was 8.91 microM, and the Vmax was 0.022 nmol min-1 mg-1. Oestrone sulphatase activity was detected in 93 of 104 human breast carcinoma samples (89%), and mean activity was 0.041 nmol min-1 mg-1 (range 0-0.399 nmol min-1 mg-1). There was no significant correlation between intratumoral oestrone sulphatase activity and oestrogen receptor status, or with any other prognostic factors. Intratumoral enzyme levels were not associated with time to recurrence or with overall survival time. It thus appears that, although a useful source of intratumoral oestrogens, oestrone sulphatase activity is not of prognostic significance in breast carcinoma.

Adult↗
PubMed1994

Effectiveness of combined limonene and 4-hydroxyandrostenedione in the treatment of NMU-induced rat mammary tumours.

Limonene, a monocyclic monoterpene, occurs naturally in orange peel oil. It has been shown to exhibit both chemopreventive and chemotherapeutic activity without toxicity in rodent models. In this study we examined the effect of limonene both at maximally optimal and suboptimal doses and in combination with suboptimal doses of 4-hydroxyandrostrenedione on nitrosmethylurea-induced rat mammary tumours. A 10% limonene dose mixed in the diet caused tumour regression in all animals. A 5% limonene dose was only able to cause regression in 50% of the rats (P < 0.05). A suboptimal dose of 4-hydroxyandrostrenedione (12.5 mg kg-1) resulted in tumour regression in 75% of rats. A combination of 5% limonene with 4-hydroxyandrostrenedione (12.5 mg kg-1) resulted in a greater tumour regression (83.3%) than either agent given individually (P < 0.001 and 0.006 for limonene/4-hydroxyandrostrenedione vs limonene alone and 4-hydroxyandrostrenedione alone respectively.

Androstenedione↗
PubMed1994

Randomised trial of epirubicin versus fluorouracil in advanced gastric cancer. An International Collaborative Cancer Group (ICCG) study.

BACKGROUND: It is not yet established whether doses of epirubicin equitoxic to adriamycin are more effective in the treatment of locally advanced or metastatic gastric cancer. PATIENTS AND METHODS: Seventy patients with advanced gastric cancer were randomised to receive fluorouracil (500 mg/m2 days 1-5 every three weeks) or epirubicin (100 mg/m2 every three weeks), with doses escalating to a maximum dose of 700 mg/m2 of fluorouracil or 140 mg/m2 of epirubicin. RESULTS: No patients attained complete response. Partial response was seen in 3 patients in the epirubicin arm (8%) compared with 2 patients in the fluorouracil arm (6%). No statistically significant difference between the two treatments was seen in either response or survival. Severe side effects, particularly alopecia, and nausea and vomiting were more common in the epirubicin arm (45% and 37%, respectively) compared with the fluorouracil arm (12% and 8%, respectively). CONCLUSIONS: Our trial demonstrates that fluorouracil and epirubicin as single agents have comparable but insufficient activity in advanced gastric cancer.

Adult↗
PubMed1994

A pilot study of intraperitoneal cisplatin in the management of gastric cancer.

BACKGROUND: This phase II trial was designed to evaluate the feasibility, toxicity, relapse pattern and survival following adjuvant intraperitoneal cisplatin in patients with gastric cancer at high risk of relapse. PATIENTS AND METHODS: Patients who had undergone complete surgical resection of adenocarcinoma of the stomach and who had positive serosa and/or regional lymph nodes and/or peritoneal washings has insertion of either a Tenckhoff catheter or temporary peritoneal dialysis catheter and were treated with cisplatin 60 mg/m2 intraperitoneally every 21 days for 4-6 courses. Peritoneal lavage or cytology was done before each treatment. RESULTS: Eighteen patients were studied. Seventeen patients had serosal involvement, 11 had regional lymph node involvement and 2 had positive peritoneal washings before treatment. The median number of courses of chemotherapy was 4 (range 2-6). Radioisotope tracer studies (6 patients) showed good distribution throughout the peritoneal cavity. No WHO grade 3/4 toxicity was seen. Twelve patients (67%) have relapsed, 6 (33%) intra-abdominally, 4 (22%) with hepatic metastases and 2 (11%) outside the abdominal cavity. The median survival was 17 months. CONCLUSIONS: Cisplatin can be administered safely as adjuvant therapy to patients with gastric cancer, however, as single agent therapy the pattern of relapse and subsequent death was similar to that expected. The occurrence of distant metastases may argue for systemic rather than local adjuvant treatment.

Adenocarcinoma↗
PubMed1994

Prospective randomized trial of tamoxifen vs surgery in elderly patients with breast cancer.

Between 1982 and 1989, 200 patients aged 70 or over seen in one Breast Unit, who were considered to have a surgically resectable cancer of the breast were prospectively randomized to primary surgery or tamoxifen 20 mg per day. At a median follow-up of 6 years (range 3-11 years) and at the censoring date there were 61 first events in the tamoxifen group. Fifty three patients developed local relapse or progression of the cancer; three patients had simultaneous local progression or relapse and distant metastases. In addition a further five patients developed distant recurrence only. In the surgical arm there were 50 events. Thirty-six patients developed local recurrence only; eight had simultaneous local and distant recurrence. A further six patients developed distant metastases of which two subsequently developed local recurrence. There were 33 deaths in the tamoxifen group and 28 deaths in the surgical group of which 17 and 15, respectively were directly attributable to breast cancer. The disease-free interval did not differ between the two groups. Following treatment with tamoxifen, at the censoring date which was the date of last clinical examination or arbitrarily, the date of death, 39 patients had no evidence of relapse whereas in the surgical arm there were 50 patients who had no evidence of recurrence. Fifty-three patients in the tamoxifen arm had local relapse only and were available for crossover to surgery, 39 accepted surgery. Eight developed further local recurrence, 10 developed distant metastases and 21 remained free of disease. Thirty-six patients in the surgical group developed local relapse only and were available for crossover to tamoxifen. Thirty one accepted treatment with tamoxifen, 14 had progression of their local recurrence, seven developed distant metastases and 10 had no further recurrence. Thus in the tamoxifen group, 39 had no progression of their disease and a further 21 benefited from subsequent surgery: 60% in all. In the surgical group 50 had no recurrence of their disease and a further 10 benefited from subsequent tamoxifen therapy: 60% in all.

Aged↗
PubMed1993

Prediction of response to endocrine therapy in breast cancer using immunocytochemical assays for pS2, oestrogen receptor and progesterone receptor.

Histological sections obtained from 70 patients with breast cancer, all of whom had received endocrine therapy for metastatic or locally advanced disease, were assessed for specific immunocytochemical staining of oestrogen receptor and the oestrogen-induced protein pS2. There was also sufficient material from 25 patients for an assessment of progesterone receptor by immunocytochemistry. We found that, when using a "cut-off" point of 50% for ER and PR, and of 25% for pS2, ER was positive in 22/29 responders and in 12/41 non-responders, and thus was significantly associated with response to endocrine therapy. Similarly, in those subjects in whom PR was measured, PR was positive in 5/14 responders and negative in all 11 non-responders, again being significantly correlated with response. However, pS2 did not relate to response, being only positive in 10/29 responders and negative in 26/41 non-responders. The different response categories varied in their "percentage of positivity" as determined by the 2 tests. Thus, for ER and pS2 we observed: complete response--71% for ER compared with 14% for pS2; partial response--77% compared with 41%; stable disease--36% compared with 64%; and progressive disease--27% compared with 27%. We conclude that at the present time ER appears to be the most reliable indicator for predicting response to endocrine therapy in patients with breast cancer.

Adult↗