Search PubMed⌕ Search

Biomedical subjects

J M Gee

Publications and source records attributed to J M Gee.

At least 37 records · Page 2Linked to original sources
PubMed2000

Gamma linolenic acid with tamoxifen as primary therapy in breast cancer.

Gamma linolenic acid (GLA) has been proposed as a valuable new cancer therapy having selective anti-tumour properties with negligible systemic toxicity. Proposed mechanisms of action include modulation of steroid hormone receptors. We have investigated the effects of GLA with primary hormone therapy in an endocrine-sensitive cancer. Thirty-eight breast cancer patients (20 elderly Stage I-II, 14 locally advanced, 4 metastatic) took 8 capsules of oral GLA/day (total = 2.8 g) in addition to tamoxifen 20 mg od (T+GLA). Quality and duration of response were compared with matched controls receiving tamoxifen 20 mg od alone (n = 47). Serial tumour biopsies were taken to assess changes in oestrogen receptor (ER) and bcl-2 expression during treatment. GLA was well tolerated with no major side effects. T+GLA cases achieved a significantly faster clinical response (objective response vs. static disease) than tamoxifen controls, evident by 6 weeks on treatment (p = 0.010). There was significant reduction in ER expression in both treatment arms with T+GLA objective responders sustaining greater ER fall than tamoxifen counterparts (6-week biopsy p = 0.026; 6-month biopsy p = 0.019). We propose GLA as a useful adjunct to primary tamoxifen in endocrine-sensitive breast cancer. The effects of GLA on ER function and the apparent enhancement of tamoxifen-induced ER down-regulation by GLA require further investigation.

Administration, Oral↗
PubMed2000

Modulation of oestrogen action by receptor gene inhibition.

Selective oestrogen receptor downregulators (SERDs) are a class of highly effective steroidal antitumour agents that reduce cellular levels of the oestrogen receptor (ER). In this study, we compared the efficacy by which three novel molecular approaches: (1) antisense oligonucleotides; (2) antisense RNA; and (3) dominant negative mutants are able to act as SERDs. Using transient and, where appropriate, stable gene transfection experiments we found that constitutive overexpression of ER antisense RNA and a hormone-binding domain compromised dominant-negative ER mutant (DNER-1), were most effective at downregulating ER expression and/or activity in vitro.

Antineoplastic Agents↗
PubMed2000

Increased induction of aberrant crypt foci by 1,2-dimethylhydrazine in rats fed diets containing purified genistein or genistein-rich soya protein.

The isoflavonoid genistein inhibits mitosis and increases apoptosis in a variety of tumour cell lines in vitro, and may exert anticarcinogenic effects in vivo. To assess its effects on the colon, rats were fed a semi-synthetic control diet, or similar diets enriched with genistein (0.25 g/kg), either as the pure isoflavone or as part of a soya protein isolate, for 7 days before receiving subcutaneous injections of saline or 1,2-dimethylhydrazine (DMH). After 48 h, rats given saline were killed and samples of their small and large intestinal mucosa were obtained for assessment of crypt cell mitosis and apoptosis by visual analysis of isolated intact crypts. Rats given DMH were fed control diet and killed after 48 h for assessment of crypt cytokinetics or maintained for 42 days then killed and their colonic mucosa analysed for aberrant crypt foci (ACF). Two further groups were given control diet before DMH, followed by the genistein or soya-based diet for 42 days before assessment of ACF. Neither genistein nor soya protein isolate had a significant effect on crypt cell mitosis or apoptosis in untreated rats, or on the proliferative response to treatment with DMH. However, consumption of pure genistein or the soya protein isolate before treatment with DMH was associated with a 3-fold (P < 0.001) or 2-fold (P < 0.05) increase, respectively, in ACF in the distal colon. There was no significant effect of genistein or soya protein isolate given after DMH treatment. We conclude that genistein has no detectable effect on colonic crypt mitosis or apoptosis in the rat in vivo, but that it promotes induction of ACF by an as yet undefined mechanism when fed immediately before treatment with DMH.

1,2-Dimethylhydrazine↗
PubMed2000

Intestinal transport of quercetin glycosides in rats involves both deglycosylation and interaction with the hexose transport pathway.

Flavonoids are polyphenolic plant secondary metabolites with antioxidant and other biological activities potentially beneficial to health. Food-borne flavonoids occur mainly as glycosides, some of which can be absorbed in the human small intestine; however, the mechanism of uptake is uncertain. We used isolated preparations of rat small intestine to compare the uptake of the quercetin aglycone with that of some quercetin glucosides commonly found in foods, and investigated interactions between quercetin-3-glucoside and the intestinal hexose transport pathway. The nature of any metabolism of quercetin and its glucosides during small intestinal transport in vitro was determined by HPLC. The presence of quercetin-3-glucoside in the mucosal medium suppressed the uptake of labeled galactose by competitive inhibition and stimulated the efflux of preloaded galactose. Quercetin-3-glucoside and quercetin-4'-glucoside, but not quercetin-3,4'-diglucoside, were transported into everted sacs significantly more quickly than quercetin aglycone. Intact quercetin glucosides were not detected in mucosal tissue or within the serosal compartment, but both free quercetin and its metabolites were present, mainly as quercetin-3-glucuronide and quercetin-7-glucuronide. Evidently, quercetin derived from quercetin-3-glucoside passes across the small intestinal epithelium more rapidly than free quercetin aglycone. Monoglucosides of quercetin interact with the sodium-dependent glucose transporter. During passage across the epithelium, quercetin-3-glucoside is rapidly deglycosylated and then glucuronidated.

Analysis of Variance↗
PubMed2000

K-ras mutations, rectal crypt cells proliferation, and meat consumption in patients with left-sided colorectal carcinoma.

It has been suggested that N-nitroso compounds derived from meat may increase the risk of K-ras mutations in the human colon. We sought evidence of associations between red meat consumption, frequency and type of K-ras mutations in resected tumours, and the rate of crypt cell proliferation (CCP) in the normal mucosa of patients with left-sided colorectal carcinoma. Meat consumption was assessed by food frequency questionnaire, and CCP was determined in rectal biopsies obtained prior to surgery. K-ras mutations in the resected tumours were determined using a PCR-based oligonucleotide hybridization assay. Fifteen K-ras mutations were detected in tumours from 43 patients; 13/15 in codon 12, 3/15 in codon 13, and 1/15 in both codons 12 and 13. All mutations were G-->A or G-->T transitions. There was no statistically significant difference between intakes of red meat in patients with a K-ras mutation (92.4 +/- 9.7 g/day) and those without (82.3 +/- 7.7 g/day). Rectal CCP was significantly higher in patients than in healthy controls, but there was no correlation with meat consumption or K-ras mutation. These data do not support the hypothesis that meat consumption is a risk factor for acquisition of K-ras mutations during colorectal carcinogenesis.

Aged↗
PubMed1999

BRCA1 expression levels predict distant metastasis of sporadic breast cancers.

The role of BRCA1 in progression of sporadic breast cancers has to date been equivocal, although preliminary studies on small numbers of samples have suggested an association between expression levels of this gene and acquisition of an invasive phenotype. We have further reasoned that loss of oestrogen receptor positivity may have a detrimental effect on BRCA1 expression. In order to test this hypothesis and extend earlier investigations we have applied a sensitive RT-PCR procedure to determine the associations between BRCA1 expression and a variety of clinical parameters in a sample cohort derived from sporadic breast tumour specimens. We have established that BRCA1 and ER mRNA expression are closely associated (p=0.013), indicating a possible functional relationship between these 2 genes. We have further identified an association between low levels of BRCA1 expression and acquisition of distant metastasis in sporadic disease (p=0.019). In light of our findings, we suggest that suppression of BRCA1 has a role to play in progression of a significant fraction of sporadic breast cancers and may additionally prove to be a useful, novel, prognostic marker for this disease type.

BRCA1 Protein↗
PubMed1999

Endocrine response and resistance in breast cancer: a role for the transcription factor Fos.

We have previously demonstrated that elevated Fos expression may be important in de novo endocrine resistance in breast cancer. However, changes in Fos expression during endocrine response and subsequently on acquisition of resistance are unknown. This study immunocytochemically monitors Fos protein within sequential biopsies from primary human breast cancer patients obtained pre-treatment (T1), during tamoxifen therapy (T2, T3) and on disease progression (T5), examining in parallel proliferation [i.e., MIBI (Ki67) immunostaining, mitotic activity], cellularity and endocrine response. Significantly diminished Fos, proliferation and cellularity were observed after 6 weeks of therapy in patients exhibiting a better quality and/or duration of response, while modest Fos increases and a maintained proliferation and cellularity were seen in poorer responders. Decreases in Fos, proliferation and cellularity at 6 months similarly hallmarked better responders. We confirmed a significant association between de novo resistance and elevated Fos and proliferation. Additionally, however, these parameters increased at the time of disease relapse over pre-treatment and "on therapy" values. Our data indicate that tamoxifen response involves a reduction in both tumor cell proliferation and cell survival, potentially entailing diminished Fos protein expression in better-responding patients. Our data are also supportive of elevated Fos expression being involved in the departure from endocrine control inherent in both primary and acquired resistance.

Aged↗
PubMed1999

p21(WAF1) expression and endocrine response in breast cancer.

An immunocytochemical assay for the p53-regulated protein product of the WAF1/Cip1 gene, p21(WAF1) (p21), was developed and applied to archival primary breast tumour material from 91 patients whose subsequent recurrent disease was treated with assessable courses of endocrine therapy. Nuclear localization of p21 protein was observed in 76 (82.4 per cent) cases. Status cut-offs were established and 29 (31.9 per cent) were deemed negative, 39 (42.9 per cent) weakly positive, and 23 (25.3 per cent) strongly positive. p21 status was inversely correlated with p53 protein (p=0.047) but did not relate to oestrogen receptor (ER) status, response to endocrine therapy, or time to further disease progression (TTP). Highly p21-positive patients had a significantly improved overall survival time (p=0. 020). Co-assessment of p21 and p53 subgroups revealed p21+/p53- patients to have good survival characteristics, whilst p21-/p53+ patients did poorly (p=0.008). The p21-/p53- patients overall did intermediately well, but Ki67-defined cellular proliferation analysis of these revealed two subclasses: those with high proliferation and poor survival times resembling the p21-/p53+ phenotype, and those with less proliferative tumours with good survival, similar to the p21+/p53- group. The significance of these results is discussed in the light of recent research concerning the role of p21 and p53 in breast cancer aetiology.

Adult↗
PubMed1999

Immunohistochemical analysis reveals a tumour suppressor-like role for the transcription factor AP-2 in invasive breast cancer.

This paper describes the generation and characterization of a monoclonal antibody specific for two members of the AP-2 family of transcription factors, AP-2alpha and AP-2beta, and its subsequent application to archival primary breast tumour material. Nuclear localization of AP-2 was found in all expressing cases, but in general levels of immunostaining were low, with only 17 per cent of the 86 tumours examined showing very high expression levels. Nevertheless, data analysis of the whole patient series allowed the identification of significant relationships between levels of AP-2 and other important breast markers. Thus, expression of AP-2alpha/beta was found to correlate significantly with expression of both ER ( p=0.036*) and the universal cell-cycle inhibitor p21(cip) ( p=0.03*), but was inversely related to levels of the proto-oncogene ErbB2 ( p=0.008*). AP-2-positive tumours also showed a low rate of proliferation, with significantly reduced mitotic count and a lower tumour grade. There was no significant relationship with clinical parameters, but samples with adjacent normal tissue indicated that loss of the AP-2 marker was associated with disease progression from normal breast through to invasive disease. This was confirmed by examining separate series of pure normal and pure DCIS samples, both of which expressed significantly higher levels of AP-2 ( p=0.0001* in each case) than the invasive tumours. Overall, these findings implicate AP-2alpha/beta as having a role akin to that of a tumour suppressor in breast cancer.

Antibodies, Monoclonal↗
PubMed1999

The immunohistochemical expression of desmoplakin and its role in vivo in the progression and metastasis of breast cancer.

Desmoplakin (DP) is a protein located at the inner plaque of desmosomes where it associates with the desmosomal cadherins to form a cell adhesion complex. Reduced expression of DP has been correlated with the progression of several cancers, but its role in in vivo breast cancer is yet to be established. The aim of this present paper was to determine the immunohistochemical (IHC) expression of DP in breast cancer specimens (n = 75) in comparison with ductal carcinoma in situ (DCIS) (n = 26), tumour associated normal (n = 29) and normal breast tissue (n = 7). DP expression was correlated with that of desmosomal cadherin, Desmoglein 2 (Dsg2) and other clinical and IHC prognostic markers. DP staining occurred at the sub-plasma membrane level. There was no significant correlation between the level of DP (as assessed by the H-score) and that of Dsg. Significantly stronger staining was demonstrated in normal breast tissue and well differentiated tumours compared with more moderately or poorly differentiated tumours (P = 0.04). A significant inverse correlation was seen between DP staining and tumour size (P = 0.01). In a limited series of 8 cases, primary tumours demonstrated significantly stronger staining than the matched metastatic lymph nodes (P = 0.046). Of all the IHC markers examined, only Ki-67 showed a significant inverse relationship with DP staining (P = 0.01). In summary, the data suggest that loss of DP may be of potential importance in progression of breast cancer in vivo from normal, DCIS, well differentiated through to poorly differentiated, large tumours. In addition, this loss may be associated with metastasis.

Breast Neoplasms↗
PubMed1999

Consumption of fish oil leads to prompt incorporation of eicosapentaenoic acid into colonic mucosa of patients prior to surgery for colorectal cancer, but has no detectable effect on epithelial cytokinetics.

Fish oil (FO) was previously reported to partially normalize colorectal crypt cell cytokinetics in patients with colorectal neoplasms. We determined the effect of FO on the fatty acid composition of colonic mucosa and mesenteric adipose tissue and on rectal crypt cell proliferation in patients undergoing surgery for colonic carcinoma. Patients (49-28 males; 21 females) were randomly assigned to consume FO capsules (2 g b.d.; FO group) containing 1.4 g eicosapentaenoic acid (EPA) and 1.0 g docosahexaenoic acid per day, or safflower oil capsules (2 g b.d.; placebo group) for an average of 12.3 +/- 0.5 d prior to surgery. Rectal biopsies were obtained at entry, at surgery, and 8-12 wk postsurgery. Colonic biopsies and samples of mesenteric adipose tissue were analyzed for fatty acids by gas-liquid chromatography. Mitosis was determined in whole crypt mounts. The proportion of EPA (g/100 g total fatty acids) in mucosal lipids was significantly greater in FO patients compared to the placebo group, but there was no effect on mesenteric adipose tissue. However self-reported use of FO supplements prior to surgery was associated with higher levels of EPA in adipose tissue. There was no significant effect of FO on the frequency or spatial distribution of crypt cell mitosis. EPA from marine oil supplements is rapidly incorporated into the colonic mucosal lipids of humans, but the levels achieved in the present study did not modify colorectal cytokinetics.

Adipose Tissue↗
PubMed1999

Involvement of steroid hormone and growth factor cross-talk in endocrine response in breast cancer.

Multiple lines of evidence implicate steroid hormone and growth factor cross-talk as a modulator of endocrine response in breast cancer and that aberrations in growth factor signaling pathways are a common element in the endocrine resistant phenotype. Delineation of these relationships is thus an important diagnostic goal in cancer research, while the targeting of aberrant growth factor signaling holds the promise of improving therapeutic response rates.

Breast Neoplasms↗
PubMed1999

Overexpression of cyclin D1 messenger RNA predicts for poor prognosis in estrogen receptor-positive breast cancer.

Cyclin D1 is a key cell cycle regulatory protein with demonstrated oncogenic activity in a variety of malignancies. Cyclin D1 mRNA and protein are overexpressed in approximately 50% of primary breast carcinomas; however, the pathophysiological consequences of increased expression remain unclear. To investigate the functional sequelae of cyclin D1 mRNA overexpression, we analyzed clinical outcome in relation to the cyclin D1 mRNA level in 253 primary breast cancer patients (median follow-up, 75 months) with particular reference to estrogen receptor (ER) status and endocrine response. Overall, with the exception of the relationship between cyclin D1 mRNA expression and the ER, cyclin D1 mRNA was not associated with other clinicopathological features such as age, menopausal status, axillary lymph node status, vascular invasion, tumor size, type, and grade. However, in patients with ER-positive tumors (n = 182), high levels of cyclin D1 mRNA were associated with increased risk of relapse (P = 0.0016), local recurrence (P = 0.025), metastasis (P = 0.019), and death (P = 0.025). In contrast, there were no clinical correlations with cyclin D1 expression in ER-negative disease (n = 71). In 33 patients who received endocrine therapy for their primary or recurrent breast cancers, there was an apparent association between a high cyclin D1 mRNA level and a shorter response duration within the ER-positive subgroup (P = 0.04). Our findings indicate that overexpression of cyclin D1 mRNA correlates with a worse prognosis within the ER-positive breast cancer phenotype and may be a contributing factor to the development of endocrine resistance in ER-positive disease.

Adult↗
PubMed1998

c-erbB3 and c-erbB4 expression is a feature of the endocrine responsive phenotype in clinical breast cancer.

We examined c-erbB3 and c-erbB4 mRNA expression in 47 primary breast cancer samples by simultaneous RT-PCR and have investigated correlations between these parameters and the expression of both ER and EGFR mRNA and protein as measured by RT-PCR and ICA and with Ki67 immunostaining. A direct association was found between c-erbB3 and c-erbB4 mRNA and ER marker status measured by either RT-PCR (c-erbB3 P = 0.0003; c-erbB4 P = 0.02) or ICA (c-erbB-3 P = 0.002; c-erbB4 P = 0.01). Inverse associations were seen between c-erbB3 and c-erbB4 mRNA marker status and EGFR membrane protein (c-erbB3: P = 0.003; cerbB4: P = 0.003) and mRNA (c-erbB4: P = 0.009) status. These associations were reinforced by Spearman Rank Correlation Tests. A significant relationship was seen between Ki67 and c-erbB4 mRNA status and level. Measurements of c-erbB3 protein levels in tumour samples removed from a further 89 patients of known response to endocrine therapy: (i) confirmed the relationship between c-erbB3 and ER and (ii) identified that patients whose ER positive tumours expressed high levels of c-erbB3 were most likely to benefit from endocrine measures. A non-significant trend was recorded between c-erbB3 levels and Ki67 immunostaining. These results clearly demonstrate that increased c-erbB3 and c-erbB4 expression appears to be associated with the prognostically-favourable ER phenotype.

Antineoplastic Agents, Hormonal↗
PubMed1998

Quercetin glucosides interact with the intestinal glucose transport pathway.

Flavonols are efficient antioxidants with the potential to protect biological macromolecules from oxidative damage in vivo, and if absorbed into the circulation they may protect against cardiovascular disease. Although flavonol aglycones are present in foods at low concentrations, their glycosides are abundant in onions, apples, beans and tea, and are thought to be stable under the conditions of the human stomach and small bowel. There is, however, recent evidence to suggest that intact glycosides of quercetin may be absorbed from the small intestine by a mechanism involving the glucose transport pathway. In the present study we tested this hypothesis by measuring the effect of quercetin glycosides on the rate of efflux of galactose from the jejunal mucosa. Everted sacs of rat jejunum preloaded with 14C-galactose were exposed to quercetin glycosides isolated from onions. Quercetin mono- and diglucosides were shown to accelerate the carrier-mediated efflux of galactose via a sodium-dependent pathway. HPLC analysis confirmed the stability of the glycosides under conditions simulating those in the upper alimentary tract. These studies suggest that purified quercetin glucosides are capable of interacting with the sodium dependent glucose transport receptors in the mucosal epithelium and may therefore be absorbed by the small intestine in vivo.

Animals↗
PubMed1998

Oestrogen-regulated genes in breast cancer: association of pLIV1 with response to endocrine therapy.

Northern hybridization analyses of the oestrogen-inducible mRNAs pLIV1 and pS2 were compared with oestrogen receptor (ER) immunocytochemistry assessments in 40 untreated primary or early recurrent breast tumours. Significant associations were observed between pLIV1/ER (P < 0.03), pS2/ER (P < 0.001) and pLIV1/pS2 (P < 0.04) status. After disease recurrence, patients were treated with assessable courses of endocrine therapies. Positive pLIV1, pS2 and ER statuses in primary disease were consequently found to be predictive of endocrine responsiveness in the secondary lesions (P < 0.03, P < 0.02, P < 0.005 respectively). However, despite these associations, a number of pLIV1- and/or pS2-positive tumours failed to respond to therapy.

Adult↗