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Biomedical subjects

D I Quinn

Publications and source records attributed to D I Quinn.

At least 19 recordsLinked to original sources

EphB4 receptor tyrosine kinase is expressed in bladder cancer and provides signals for cell survival.

We sought to evaluate the biological function of the receptor tyrosine kinase EphB4 in bladder cancer. All of the nine bladder cancer cell lines examined express EphB4 and the receptor could be phosphorylated following stimulation with its cognate ligand, EphrinB2. Out of the 15 fresh bladder cancer specimens examined, 14 expressed EphB4 with a mean sevenfold higher level of expression compared to adjacent normal urothelium. EphB4 expression was regulated by several mechanisms: EPHB4 gene locus was amplified in 27% tumor specimens and 33% cell lines studied; inhibition of EGFR signaling downregulated EphB4 levels; and forced expression of wild-type p53 reduced EphB4 expression. EphB4 knockdown using specific siRNA and antisense oligodeoxynucleotides molecules led to a profound inhibition in cell viability associated with apoptosis via activation of caspase-8 pathway and downregulation of antiapoptotic factor, bcl-xl. Furthermore, EphB4 knockdown significantly inhibited tumor cell migration and invasion. EphB4 knockdown in an in vivo murine tumor xenograft model led to a nearly 80% reduction in tumor volume associated with reduced tumor proliferation, increased apoptosis and reduced tumor microvasculature. EphB4 is thus a potential candidate as a predictor of disease outcome in bladder cancer and as target for novel therapy.

Base Sequence↗

Expression analysis of genes involved in oxaliplatin response and development of oxaliplatin-resistant HT29 colon cancer cells.

The interrelationship between platinum resistance and clinical response is not well established. The purpose of this study is to evaluate the expression of 14 genes involved in platinum resistance in a colon cancer cell line (HT29) and its oxaliplatin (OXA)-resistant sublines. Resistant cells exhibited lower expression of many of these genes suggesting that several pathways may be implicated in OXA resistance. Particularly, OXA resistance is accompanied by defects in drug uptake (downregulation of the hCTR1 transporter) and enhanced DNA repair (upregulation of the XPD gene). Our data also confirmed that copper transporters and chaperones are involved in OXA resistance in colorectal cancer cells as evidenced by the overexpression of ATP7A and CCS in response to OXA exposure. Moreover, increased CCS expression suggests a role for SOD1 in OXA detoxification. Whereas exposure to OXA in HT29 induced significant changes in expression of many of the genes analyzed, only ATP7A, XPD and SRPK1 gene expression was increased in OXA-treated HTOXAR3 resistant cells. To our knowledge, this is the first report of implicating SRPK1 in OXA resistance. This study provides the basis for further evaluation of these putative markers of OXA response and resistance in colorectal cancer patients who are candidates for treatment with OXA.

Adenosine Triphosphatases↗

Phase II trial of tesmilifene plus mitoxantrone and prednisone for hormone refractory prostate cancer: high subjective and objective response in patients with symptomatic metastases.

PURPOSE: Symptomatic, hormone refractory prostate cancer (HRCAP) is a major cause of morbidity with a median survival of less than 12 months and a 2-year survival of only up to 10% in most series. Mitoxantrone has been approved by the Food and Drug Administration for HRCAP. Preliminary data suggest that DPPE (N,N-diethyl-2-[4-(phenylmethyl) phenoxy]-ethanamine) or tesmilifene modulates cytotoxics to enhance the anticancer effect. In this phase II trial we assessed whether there is sufficient evidence of enhanced efficacy of DPPE and mitoxantrone to lead to a phase III clinical trial. MATERIALS AND METHODS: A total of 29 patients with a median age of 73 years, of whom 10% were older than 80 years, with progressive HRCAP received 5.3 mg/kg DPPE intravenously every 3 weeks, 12 mg/m mitoxantrone intravenously every weeks and 5 mg prednisone orally twice daily. All patients had pain at presentation, while 97% had bone metastases, 10% had liver metastases and 17% had lung metastases. Median prostate specific antigen (PSA) was 210 ng/ml (IQR 77 to 430). RESULTS: Of the patients 75% had some pain improvement, 66% had decreased analgesia, 59% had a PSA decrease of 50% or greater and 45% had a PSA decrease of 75% or greater. Actual (not actuarial) 2-year survival was 21%. CONCLUSIONS: Despite major limitations of historical comparison the PSA decrease and decreased symptoms with DPPE-mitoxantrone-prednisone compare favorably to those of mitoxantrone-prednisone and docetaxel-estramustine in the literature. The 2-year survival rate of 21% mandates further assessment. This will be tested in a phase III Southwest Oncology Group trial.

Adenocarcinoma↗

Molecular prognostication in bladder cancer--a current perspective.

The optimal management of bladder cancer depends on the accurate assessment of the tumour's biological potential. Advances in molecular biology and cytogenetics have spurred intense research in identifying and characterising prognostic markers for patients with transitional cell carcinoma (TCC) of the bladder. The molecular changes that occur can be categorised into (1) chromosomal alterations leading to carcinogenesis, (2) cellular proliferation as a result of dysregulation of cell cycle control, and (3) growth control processes such as angiogenesis leading to metastasis. The accumulation of these changes ultimately determines a tumour's clinical behaviour and response to therapy. As the understanding of bladder cancer evolves, novel molecular markers for prognostication will make their way from the research laboratory to the clinical setting with the promise to improve patient care and outcomes.

Biomarkers, Tumor↗

Downregulation of KAI1 mRNA in localised prostate cancer and its bony metastases does not correlate with p53 overexpression.

Recent data have proposed that transcription of the KAI1 metastasis suppressor gene is directly mediated by p53 and that loss of KAI1 expression in advanced prostate cancer is simply due to loss of p53 function after mutation. To investigate this possibility, we have examined KAI1 mRNA (by in situ hybridisation) and p53 protein expression (by immunohistochemistry) as an indicator of wildtype or mutant p53, in a series of 77 paraffin-embedded prostate tissue samples, including post-mortem normal prostates (2), benign prostatic hyperplasia (10), localised cancer (grades 4-6, 25; grades 7-9, 21) and prostate-derived bony metastases (19). Overall, we confirmed that expression of KAI1 mRNA decreased from normal tissue, through localised cancer to bony metastases (P=0.055, tending to significance), while levels of p53 staining significantly increased with cancer progression (P=0.046). These were consistent with the possibility that loss of p53 function might be responsible for loss of KAI1 mRNA. However, by close examination of KAI1 and p53 in adjacent tissue sections, we found no correlation between decreased levels of KAI1 mRNA and overexpression of p53 protein (P=0.497). In addition, high levels of KAI1 mRNA could be identified in samples irrespective of p53 staining. Our data suggest that mutation of p53 is independent of the loss of KAI1 mRNA, and do not support a role for p53 in regulating the expression of KAI1.

Adult↗

Prognostic significance of pathologic features in localized prostate cancer treated with radical prostatectomy: implications for staging systems and predictive models.

PURPOSE: Although predicting outcome for men with clinically localized prostate cancer (PC) has improved, the staging system and nomograms used to do this are based on results from the North American health system. To be internationally applicable, these models require testing in cohorts from a variety of different health systems based on the predominant PC case identification methods used. PATIENTS AND METHODS: We studied 732 men with localized PC treated with radical prostatectomy and no preoperative therapy between 1986 and 1999 at one Australian institution to determine the effect of clinicopathologic features on disease-free survival. RESULTS: Preoperative serum prostate-specific antigen (PSA) concentration, Gleason score, pathologic stage, and year of surgery were independent predictors of outcome. Although margin status demonstrated only a trend toward significance in multivariate modeling overall, it proved to be independent in subgroups based on later year of surgery (1986 to 1994 v 1995 to 1998), preoperative PSA of less than 10 ng/mL, and Gleason score > or = 7. Adjuvant radiation therapy improved disease-free survival rates in patients with multiple surgical margin involvement. CONCLUSION: This work confirms the prognostic significance of pathologic stage, Gleason score, and preoperative serum PSA. In the context of a contemporaneous screening effect in Australia, these findings may have implications for methods that predict outcome following surgery as screening becomes more prevalent in a population. The independent prognostic effect of margin status may alter with an increase in the proportion of screening-identified PCs. Staging systems and nomograms that predict outcome following surgery require validation in cohorts with different health practices before being universally applied.

Adenocarcinoma↗

Frequent loss of estrogen receptor-beta expression in prostate cancer.

The role of estrogen and its receptors in the etiology and progression of prostate cancer (PC) is poorly understood. In normal and malignant human prostate, estrogen receptor-alpha is expressed only in the stroma, whereas estrogen receptor-beta (ERbeta) is present in both normal stroma and epithelium. Because loss of ERbeta expression is associated with prostate hyperplasia in ERbeta-null mice, this study determined patterns of ERbeta expression in normal, hyperplastic, and malignant human prostate and associations with clinical outcome. Five normal prostates from organ donors and 159 radical prostatectomy specimens from patients with clinically localized PC were assessed for ERbeta expression using immunohistochemistry. ERbeta-positivity was defined as > or =5% of cells demonstrating nuclear immunoreactivity. All of the five normal prostates showed strong ERbeta-nuclear staining in >95% of the epithelium and 35% of the stromal cells. The number of ERbeta-positive cases declined to 24.2% (38/157) in hyperplasia adjacent to carcinoma and 11.3% (18/159) in PCs. ERbeta-positivity was related to decreased relapse-free survival (log-rank P = 0.04). Thus, loss of ERbeta expression is associated with progression from normal prostate epithelium to PC, whereas those cancers that retained ERbeta expression were associated with a higher rate of recurrence. These data identify the need to further investigate the potential role of ERbeta in the regulation of prostate epithelial cell proliferation and the functional consequences of decreased ERbeta expression in the evolution of PC.

Adult↗

Altered expression of androgen receptor in the malignant epithelium and adjacent stroma is associated with early relapse in prostate cancer.

The molecular basis of androgen-independent prostate cancer is unknown; however, functional androgen receptor (AR) signaling is maintained after the acquisition of hormone-refractory disease. Because normal and malignant prostate epithelial cell proliferation is regulated by androgen stimulation via both the AR-positive stroma and epithelium, we sought to evaluate patterns of AR expression in these cells and to determine any relationships with prostate cancer progression. AR expression in the malignant epithelium and associated periepithelial and nonperiepithelial stroma was measured in a cohort of 96 patients with clinically localized prostate cancer treated with radical prostatectomy. Data were evaluated for disease relapse using the Kaplan-Meier method and in a Cox proportional hazards model with other variables of known clinical relevance, including Gleason score, pathological stage, clinical stage, and pretreatment prostate-specific antigen concentration. Concurrent overexpression of AR (> or = 70% positive nuclei) in the malignant epithelium and loss of AR immunoreactivity in the adjacent periepithelial stroma (< or = 30%) was associated with higher clinical stage (P = 0.01), higher pretreatment prostate-specific antigen level (P = 0.03), and earlier relapse after radical prostatectomy (log-rank P = 0.009). These data identify a pattern of AR expression in malignant epithelium and adjacent stroma that is associated with a poor clinical outcome in prostate cancer. Equally important, they identify the need to further investigate the mechanistic basis of loss of AR expression in the malignant stroma and its potential role in deregulation of prostate epithelial cell proliferation.

Aged↗

Overexpression of the cell cycle inhibitor p16INK4A in high-grade prostatic intraepithelial neoplasia predicts early relapse in prostate cancer patients.

Prostate cancer (PC) is the most commonly diagnosed male cancer in industrialized societies. No molecular markers of PC progression or outcome with proven clinical utility have been described. Because the loss of normal cell cycle control is an early event in the evolution of cancer, we sought to determine whether changes in expression of the cyclin-dependent kinase inhibitor, p16INK4A, predicted outcome in this disease. We screened a cohort of 206 patients with clinically localized PC treated with radical prostatectomy for overexpression of the INK4A gene, the product of which inactivates the G1-phase cyclin dependent kinases, Cdk4 and Cdk6. p16INK4A protein expression was evaluated by immunohistochemistry in areas of high-grade intraepithelial neoplasia (HGPIN), a precursor to invasive disease, and of cancer in the same specimen. Data were evaluated for disease relapse using the Kaplan-Meier method and in a Cox proportional hazards model by assessing p16INK4A status in areas of HGPIN and cancer with other variables of known clinical relevance. Overexpression of p16INK4A in HGPIN and cancer was correlated with, but independent of, pathological stage and was associated with early relapse in PC patients treated with radical prostatectomy (log-rank test, P < 0.001). In a multivariate model adjusted for Gleason grade, pretreatment prostate-specific antigen levels, pathological stage, and margin status, overexpression of p16INK4A in HGPIN was an independent predictor of disease relapse and increased the risk of recurrence 2.24-fold (95% confidence interval, 1.28-3.93). These data provide the first evidence for a prognostic marker in HGPIN. The clinical utility of p16INK4A status in stratifying patients for aggressive treatment very early in the disease process, potentially several years prior to the onset of invasive disease, requires further investigation.

Age Factors↗

Prognostic significance of p53 nuclear accumulation in localized prostate cancer treated with radical prostatectomy.

The role of p53 in the pathogenesis of, and as a predictive biomarker for, localized prostate cancer (PCa) is contested. Recent work has suggested that patterns of p53 nuclear accumulation determined by immunohistochemistry are prognostic, whereas studies using other methods question the role of p53 mutations in predicting outcome. We studied 263 men with localized PCa treated with radical prostatectomy to determine whether p53 nuclear accumulation predicts relapse and disease-specific mortality. We combined two p53 immunohistochemistry scoring systems: (a) percentage of p53-positive tumor nuclei in all major foci of cancer within the prostate; and (b) clustering, where the presence of 12 or more p53-positive cells within a x 200 power field was deemed "cluster positive." Analysis was undertaken using chi2, Kruskal-Wallis, and Mann-Whitney tests for clinicopathological variables and the Kaplan-Meier method, log-rank test, and univariate and multivariate Cox regression modeling for evaluation of contribution to relapse and disease-specific survival. At mean follow-up of 55.1 months (range, 4.9-123.0 months), 39% (102 of 263) of patients had relapsed and 2.3% (6 of 253) had died of PCa. Pretreatment serum prostate-specific antigen concentration, pathological tumor stage, lymph node involvement, Gleason score, and p53 nuclear accumulation, as determined by either percentage score or cluster status, were independent predictors of relapse in multivariate analysis. Clustering of p53-positive cells distinguished between favorable and poor prognosis patients within the lowest p53-positive stratum (>0 to <2%) and was the most discriminatory threshold for predicting relapse in the entire cohort. p53 status predicted outcome in patients with a Gleason score of 5 and above but not those with a score of 4 and below. In patients treated with neoadjuvant hormonal therapy, p53 cluster positivity carried a 90% (19 of 21) risk of relapse by 36 months. All six patients who died from PCa in the period of the study exhibited p53 nuclear accumulation in 20% or more tumor nuclei. This study demonstrates strong relationships between p53 nuclear accumulation and relapse and disease-specific mortality in a large series of localized PCas. Furthermore, the presence of clusters of p53-positive nuclei delineates a group of patients with poor prognosis not identified by traditional scoring methods and supports the hypothesis that p53 dysfunction within PCa may exist in foci of tumor cells that are clonally expanded in metastases.

Aged↗

Elevated levels of peritumoral chondroitin sulfate are predictive of poor prognosis in patients treated by radical prostatectomy for early-stage prostate cancer.

The disease course of localized prostate cancer is highly variable, and patients potentially curable by aggressive management are not readily identified by current clinical practice. Chondroitin sulfate (CS) glycosaminoglycan is a candidate biomarker as elevated levels of CS in peritumoral stroma of prostate cancer have been associated with prostate-specific antigen (PSA) failure. Immunoreactive CS was measured using image analysis of archived radical prostatectomy tissues, obtained from 157 men with a median of 47 months (range, 16-111 months) clinical follow-up. CS level, Gleason score, and preoperative serum PSA levels were independent predictors of PSA failure by Cox's multivariate analysis. Patients with low CS levels had significantly fewer PSA failures after radical prostatectomy than patients with high levels of CS (Kaplan-Meier plot; 32% PSA failures at 5 years for CS mean integrated absorbance cut point < 7.0 versus 50% for CS > or = 7.0, P = 0.0001). In the subgroup of patients with preoperative serum PSA levels < 10 ng/ml, CS was particularly useful in discriminating retrospectively those patients most suited for surgery (Kaplan-Meier plot; 14% PSA failures at 5 years for CS mean integrated absorbance cut point < 7.0 versus 47% for CS > or = 7.0, P = 0.0001). We conclude that measurements of CS level can assist in predicting patient outcome after surgery. Additionally, our data suggest that the combination of CS and PSA measurements may improve outcome prediction for patients with intermediate Gleason scores.

Adenocarcinoma↗

Aggressive cutaneous malignancies following cardiothoracic transplantation: the Australian experience.

BACKGROUND: The development of malignancies in recipients of a cardiothoracic transplant (CTT)--that is, heart, lung, or heart and lung recipients-is of concern. Cutaneous and lymphoproliferative malignancies comprise the two major groups of malignancies encountered. A small subgroup of patients will develop potentially life-threatening aggressive cutaneous malignancies (ACM); these are poorly defined and documented in the literature. The authors report the results for 619 CTT recipients from a single institution. METHODS: Between 1984 and 1995, 619 recipients received a CTT. With a minimum follow-up of 2 years, 66 patients (10.7%) were diagnosed with a major malignancy, and 27 of these 66 patients developed ACM. ACM were defined as having one or more of the following characteristics: local invasion and/or regional metastases at diagnosis, poor differentiation, and locoregional and/or systemic relapse following therapy. All malignant melanomas were considered ACM. Data on malignancy occurrence were documented in the clinical notes of the heart and lung transplant unit. A retrospective analysis was undertaken from these notes. RESULTS: Tumor histology was predominantly poorly differentiated squamous cell carcinoma (55%) (SCC) and malignant melanoma (30%) (MM). No patient developed Kaposi sarcoma (KS). The median time from transplant to diagnosis of ACM was 52 months (range, 8-127 months). Thirteen of 27 patients have died; 10 of them died of metastatic disease. The mean time to death was 20 months (range, 8-54 months). Of 14 patients alive, 5 have disease. All but one of the 19 patients diagnosed with nonmelanoma ACM received radiotherapy, either as part of initial treatment or on relapse. Eight patients have subsequently suffered an infield relapse. CONCLUSIONS: The development of ACM in CTT recipients resulted in substantial morbidity and mortality. Poor results were obtained with standard surgery and radiotherapy. Treatment modalities for and the underlying pathobiology of ACM in organ transplant recipients require detailed research if improved outcomes are to be achieved.

Adult↗

Cyclin D1 and p16INK4A expression predict reduced survival in carcinoma of the anterior tongue.

Cyclin D1 and p16INK4A are molecules with pivotal roles in cell cycle control and the development of diverse human cancers, and overexpression of cyclin D1 and loss of p16INK4A expression are common genetic events in head and neck squamous cell carcinoma. The prognostic significance of these molecular events at different sites within the head and neck, however, remains controversial. Thus, we sought to determine the relationship between cyclin D1 and/or p16INK4A expression and disease outcome in squamous cell carcinoma of the anterior tongue. Immunohistochemical detection of nuclear proteins cyclin D1, p53, and p16INK4A, and the Ki-67 labeling index was undertaken in tissue sections from 148 tongue cancers treated by surgical resection. Nuclear antigen status was analyzed in relation to pathological variables, tumor recurrence, and patient survival. Statistical significance was assessed using chi2 analysis for pathological variables and the Kaplan-Meier method, log rank test, and the Cox proportional hazards model for survival parameters. Overexpression of cyclin D1 occurred in 68% of tumors (100 of 147) and was associated with increased lymph node stage (P = 0.014), increased tumor grade (P = 0.003), and reduced disease-free (P = 0.006) and overall (P = 0.01) survival. Loss of p16INK4A expression was demonstrated in 55% of tumors (78 of 143) and was associated with reduced disease-free (P = 0.007) and overall (P = 0.014) survival. Multivariate analysis confirmed that in addition to pathological stage and regional lymph node status, cyclin D1 overexpression and loss of p16INK4A expression are independent predictors of death from tongue cancer. Loss of p16INK4A in the presence of cyclin D1 overexpression conferred a significantly worse disease-free (P = 0.011) and overall (P = 0.002) survival at 5 years. p53 nuclear accumulation and the Ki-67 labeling index were not prognostic. These data indicate that cyclin D1 overexpression and loss of p16INK4A expression predict early relapse and reduced survival in squamous cell carcinoma of the anterior tongue. Simultaneous assessment of cyclin D1 and p16INK4A protein levels define subgroups of patients at increased risk of relapse and may be of clinical utility in optimizing therapy.

Carcinoma, Squamous Cell↗

Granulosa cell tumors express erbB4 and are sensitive to the cytotoxic action of heregulin-beta2/PE40.

The molecular genetic events involved in the etiology of human granulosa cell (GC) tumors, which represent approximately 7% of all malignant ovarian neoplasms, are unknown. Amplification and/or overexpression of the ERBB genes are a feature of many cancer types, and overexpression of erbB2 correlates with poor prognosis in epithelial ovarian cancer. In the present study, we used immunohistochemistry to determine the level and frequency of expression of different erbB receptors in GC tumors. Ten of 12 tumors expressed erbB4 at moderate to high levels in >50% of cancer cells, whereas erbB2 (6 of 12) and erbB3 (2 of 12) were expressed less frequently. Western blot experiments showed that the only available GC tumor cell line, COV434, also expressed erbB receptors. Heregulin (HRG)-beta2, a ligand for erbB3 and erbB4 receptors, stimulated tyrosine phosphorylation of the erbB receptors, which was accompanied by activation of Erk1 and Erk2, two mitogen-activated protein kinases with a functional role in mitogenesis. Importantly, HRG increased cell proliferation in COV434 cells, and treatment with HRG/PE40, a ligand toxin shown previously to be cytotoxic against human breast cancer cells overexpressing erbB receptors, led to a dramatic and irreversible decrease in cell number. These results indicate that erbB receptor signaling pathways may be critical in the control of GC tumor cell proliferation and that HRG/PE40 is a potential therapeutic agent for the treatment of GC tumors.

Blotting, Northern↗

Pharmacokinetic and pharmacodynamic principles of illicit drug use and treatment of illicit drug users.

Many clinicians are confronted by the use of illicit drugs on a daily basis. The unsanctioned use of opioids, psychostimulants, benzodiazepines, alcohol and nicotine is a major cause of morbidity and mortality. Multiple factors have inhibited the scientific study of these agents including prohibition, public denial and lack of commercial interests. In dealing with problems related to these drugs, clinicians need a scientific understanding of their pharmacology, quantifiable effects and potential adverse effects. Illicit drug users select drugs with particular pharmacokinetic parameters and pharmacodynamic properties. Generally, rapid absorption, rapid entry into the central nervous system, high bioavailability, short half-life, small volume of distribution and high free drug clearance are pharmacokinetic characteristics which predict a high potential for harmful use because these factors increase positive reinforcement. Drug users adapt the method and route of drug administration to optimise the delivery of the drug to the brain while attempting to maximise the bioavailability of the drug. Inhalation and smoking are the routes of administration which allow the most rapid delivery of drug to the brain, while intravenous injection maximises the bioavailability of an administered drug. Each route of administration results in attendant complications related to mucosal damage, carcinogenesis and risk of infection. Negative reinforcement or withdrawal is a major drive to recurrent use. Many illicit drugs have pharmacological features that promote dependence, including long half-life, low free drug clearance and sufficient drug exposure to allow development of tolerance. The preventive or reductive pharmacotherapeutics of illicit drug use makes use of several subsets of agents: those which act on the same receptor or system as the illicit drug (such as methadone), those which produce an adverse reaction on consumption of the illicit drug (such as disulfiram) and those which symptomatically attenuate illicit drug withdrawal symptoms (such as clonidine). Many new agents are being trialled as potential preventive or reductive agents. It is important to consider pharmacotherapy as only one potential part of the treatment of illicit drug users. The complications of illicit drug use present many therapeutic challenges. As with all patients consuming multiple drugs, illicit drug users are prone to developing drug interactions. The most common interactions seen in practice are pharmacodynamic in nature, most often due to the additive effects of different drugs on the central nervous system. However, alcohol, cocaine, disulfiram, methadone and tricyclic antidepressants may be involved in important pharmacokinetic interactions. Of these the effect of long term alcohol consumption in increasing the hepatotoxicity of paracetamol and of cytochrome P450 3A microsomal enzyme stimulating drugs in diminishing the efficacy of methadone are the most commonly encountered.

Drug Interactions↗