Predicting the long-term risk of prostate cancer-specific mortality after radical prostatectomy

5007

Background: Nomograms that predict prostate-specific antigen (PSA) defined biochemical recurrence (BCR) of prostate cancer after radical prostatectomy are the most widely used prediction tools in oncology for treatment decision making and counseling. While BCR universally antedates prostate cancer-specific mortality (PCSM), it is a limited surrogate endpoint due to its variable natural history. Nomograms that accurately predict the risk of PCSM are needed. Methods: Using Fine and Gray competing risk regression analysis, the clinical data and follow-up information of 11,521 patients treated with radical prostatectomy at four academic centers from 1987 to 2005 were modeled to predict PCSM. The model was externally validated on 12,893 patients treated at a separate institution during the same period. Results: The 15-year PCSM and all-cause mortality was 7% and 33%, respectively. The 15-year PCSM for patients with final pathological Gleason score 2–6, 3+4, 4+3, and 8–10 was 1%, 7%, 8%, and 49%, respectively. By pathologic stage, the risks were 2%, 7%, 29%, and 23% for organ-confined, extraprostatic extension, seminal vesicle invasion, and lymph node-positive prostate cancer. Of 3756 patients with organ-confined and Gleason 2–6 cancer, only 1 (0.03%) died from prostate cancer. Primary and secondary Gleason grade (p < 0.001 for both), seminal vesicle invasion (p < 0.001), and year of surgery (p = 0.002) were significant predictors of PCSM. A nomogram predicting 15-year PCSM based on pathologic parameters was accurate and discriminating with an externally-validated concordance index of 0.92. Conclusions: A nomogram has been constructed that predicts the long-term risk of PCSM after radical prostatectomy based on the pathologic grade and stage of the cancer. The presence of poorly differentiated cancer and seminal vesicle invasion are the prime determinants of PCSM. Our study suggests that biomarkers may have limited empiric prognostic utility as PCSM can be accurately predicted once the pathologic features of prostate cancer are known.

No significant financial relationships to disclose.

Survival following early hormone therapy for men with rapid PSA doubling time within 2 years following radical prostatectomy

5065

Background: Early hormonal therapy has been used in the salvage setting for men with biochemical recurrence following radical prostatectomy (RP), but no studies to date have been able to evaluate whether such treatment prolongs survival. We examined the impact of salvage hormonal therapy on overall survival (OS) in a cohort with long-term follow-up, and attempted to identify the subgroup most likely to benefit. Methods: Retrospective analysis of a cohort of 488 men undergoing RP at Johns Hopkins Hospital from 1982–2004, who experienced biochemical recurrence and received no salvage therapy (n = 386) or salvage hormonal therapy (n = 102); no one received adjuvant therapy. Survival was defined from biochemical recurrence to death from all causes, and analyzed with proportional hazards models with time-dependent covariates. Results: With median follow-up of 6 years after recurrence and 9 years after RP, there were 143 deaths (29%), including 105 from prostate cancer. After adjusting for PSA doubling time (PSADT), RP Gleason score, and year of surgery, hormonal therapy did not significantly improve OS for all men, compared to no salvage therapy: hazard ratio (HR) = 0.72 (95% confidence interval (CI): 0.45–1.17), p = 0.187. However, when restricted to men with early recurrence, i.e. within 2 years of RP, and with a rapid PSADT<6 months, hormonal therapy was associated with a large, significant improvement in OS: HR = 0.25 (95% CI: 0.08–0.71), p = 0.0095. This subgroup comprised 22% of the cohort. In contrast, there was no benefit of salvage hormonal therapy in men with early recurrence and PSADT>6 months: HR = 1.96 (95% CI: 0.89–4.31), p = 0.093, nor those who recurred more than 2 years after RP, regardless of PSADT. Conclusions: This study suggests that early salvage hormonal therapy may significantly and substantially prolong overall survival in the subgroup of men who experience an early biochemical recurrence with a rapid PSADT. These results are consistent with early recurrences being indicative of metastatic disease, while later recurrences are more likely to represent local recurrence. If validated, these results may provide useful stratification criteria for clinical trials.

No significant financial relationships to disclose.

Deviation from Archie's law in partially saturated porous media: Wetting film versus disconnectedness of the conducting phase

We experimentally study the electrical transport in partially water-saturated pore network. The porous medium under investigation is a Fontainebleau sandstone, characterized by x-ray tomography. We show the existence of two electrical conductivity regimes. At high water saturation, the electric resistivity follows a well-known Archie law. Below a water saturation S_{w} approximately 0.2 , a strong negative deviation from this Archie law is observed. We attribute this transition to the existence of "a thick liquid film," assuring the ionic conduction in the low saturation regime. A numerical simulation is proposed to confirm this scenario. Two possible protocols are used to distribute the brine phase in the pore network of a three-dimensional microtomography image. The first one is based on a minimization of the interfacial energy. The second takes into account a quasistatic capillary displacement. The classical random-walk algorithm is used to compute the electric conductivity at various water saturations. Without the "thick film," both of the two fluid-placing protocols show a disconnectedness transition of the brine phase when S_{w}<0.2 . Adding this "film" to solid surface, the electrical continuity is maintained. The bending down trend is correctly reproduced, showing that in this range, the electric response cannot be described by a power law as usual.

Local structural and electrical properties of ferroelectric Bi3.25La0.75Ti3O12 thin films on Pt

Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been grown by a sol-gel method. Annealing conditions after the drying process have been explored over a wide range of temperature. BLT thin films prepared on Pt/TiO2 coated SiO2/Si(100) were investigated by Raman scattering spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy. Raman spectra reveal the growth route of phase-formation of the BLT films. Ferroelectric domains in the thin films are observed by using AFM, registering the electrostatic force response of the thin films in the presence of a low ac field. It is found that the as-grown domain configuration and switching behavior are strongly dependent on growth temperature. Depth-profiling of the electronic states of Bi, Ti, and La atoms shows the oxidation during the growth.

Mismatch repair gene mutations in Chinese HNPCC patients

To explore the characteristics of DNA mismatch repair gene mutations in Chinese patients with hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome, the MLH1 and MSH2 genes from probands of 76 HNPCC families were sequenced. By doing so, two frame-shift mutations, three splice-site mutations and fourteen missense mutations (thirteen missense mutations and one nonsense mutation) were identified in the MLH1 gene. In addition, one splice-site mutation and six missense mutations were detected in the MSH2 gene. None of these mutations were detected in 100 matched healthy controls. The remaining mutation-negative cases were subjected to large fragment deletion analysis using multiplex ligation-dependent probe amplification (MLPA). By doing so, five large fragment deletions were detected in the MSH2 gene. No large fragment deletions were detected in the MLH1 gene. We conclude that the MLH1 and MSH2 genes in Chinese HNPCC families exhibit broad mutation spectra.

Evidence for suppression of electroacupuncture on spinal glial activation and behavioral hypersensitivity in a rat model of monoarthritis

Our previous study demonstrated that single intrathecal (i.t.) application of fluorocitrate, a glial metabolic inhibitor, synergized electroacupuncture (EA) antagonizing behavioral hypersensitivity in complete Freund's adjuvant (CFA)-induced monoarthritic rat. To further investigate the relationship between spinal glial activation and EA analgesia, the present study examined the effects of multiple EA on spinal glial activation evoked by monoarthritis (MA). The results showed that (1) unilateral intra-articular injection of CFA produced a robust glial activation on the spinal cord, which was associated with the development and maintenance of behavioral hypersensitivity; (2) multiple EA stimulation of ipsilateral "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints or i.t. injection of fluorocitrate (1 nmol) significantly suppressed spinal glial activation; (3) inhibitory effects of EA on spinal glial activation and behavioral hypersensitivity were significantly enhanced when EA combined with fluorocitrate, indicating that disruption of glial function may potentiate EA analgesia in inflammatory pain states. These data suggested that analgesic effects of EA might be associated with its counter-regulation to spinal glial activation, and thereby provide a potential strategy for the treatment of arthritis.

Specific interaction between the initiator protein (Rep) and origin of plasmid ColE2-P9

The replication initiator protein (Rep) of plasmid ColE2-P9 (ColE2) is multifunctional. We are interested in how Rep binds to the origin (Ori) to perform various functions. We used the wild type and variants of Rep to study the Rep-Ori interaction by both in vitro and in vivo approaches, including biochemical analyses of protein-DNA interactions and an in vivo replication assay. We identified three regions (I, II, and III) of Rep, located in the C-terminal half, and three corresponding binding sites (I, II, and III) in Ori which are important for Rep-Ori interaction. We showed that region I, containing a putative helix-turn-helix motif, is necessary and sufficient for specific Ori recognition, interacting with site I of the origin DNA from the major groove. Region II interacts with site II of the origin DNA, from the adjacent minor groove in the left half of Ori, and region III interacts with site III, next to the template sequence for primer synthesis, which is one and one-half turn apart from site I on the opposite surface of the origin DNA. A putative linker region located between the two DNA binding domains (regions II and III) was identified, which might provide Rep an extended conformation suitable for binding to the two separate sites in Ori. Based on the results presented in this paper, we propose a model for Rep-Ori interaction in which Rep binds to Ori as a monomer.

Sebum output as a factor contributing to the size of facial pores

BACKGROUND

Many endogenous and exogenous factors are known to cause enlarged pilosebaceous pores. Such factors include sex, genetic predisposition, ageing, chronic ultraviolet light exposure, comedogenic xenobiotics, acne and seborrhoea. This study was an attempt to determine the factors related to enlarged pores.

OBJECTIVES

To assess the relationship of sebum output, age, sex, hormonal factors and severity of acne with pore size.

METHODS

A prospective, randomized, controlled study was designed. A total of 60 volunteers, 30 males and 30 females, were recruited for this study. Magnified images of pores were taken using a dermoscopic video camera and measured using an image analysis program. The sebum output level was measured with a Sebumeter.

RESULTS

Using multiple linear regression analysis, increased pore size was significantly associated with increased sebum output level, sex and age. Among the variables, sebum output level correlated most with the pore size followed by male sex. In comparing male and female participants, males had higher correlation between the sebum output level and the pore size (male: r = 0.47, female: r = 0.38). Thus, additional factors seem to influence pore size in females. Pore size was significantly increased during the ovulation phase (P = 0.008), but severity of acne was not significantly associated with the pore size.

CONCLUSIONS

Enlarged pore sizes are associated with increased sebum output level, age and male sex. In female patients, additional hormonal factors, such as those of the menstrual cycle, affect the pore size.

PPARr agonist, troglitazone induce growth arrest and apoptosis in MDA-MB-231 human breast cancer cell

13155

Background: Estrogen receptor (ER)-negative breast carcinomas do not respond to hormone therapy, making their effective treatment very difficult. It is recently reported that peroxisome proliferator-activated receptor-gamma (PPAR-γ) has become a potential target for the prevention and treatment of human cancer. Therefore, PPAR-γ agonist, troglitazone has been extensively studied as a chemopreventive or therapeutic agent in several types of cancer. The purpose of this study was to assess whether troglitazone (TRO) would induce cell growth arrest and apoptosis in MDA-MB-231 (ER-negative) human breast cancer cells. Methods: Cytostatic/cytotoxic effects of troglitazone were measured with MTT assay. The cell cycle distribution was evaluated with flow cytometer. The expression of cyclin-dependent kinase inhibitors, p21, p27, and cell cycle dependent kinases was measured with Western blotting. Apoptotic cells were determined by Hoechst staining and TUNEL assay. Results: Troglitazone inhibited cell proliferation by inducing 65% G0/G1 arrest after 48 h. Accumulation of cells in G0/G1 was accompanied by a decrease of Rb protein phosphorylation associated with reduced activities of cell cycle dependent kinases (CDKs) such as cdk2 and cyclin D. Troglitazone increased the expression cyclin kinase inhibitors, p21 and p27 as MDA-MB-231 cell underwent G0/G1 arrest. Apoptotic effect by troglitazone demonstrated that apoptotic cells elevated from 2.5-fold of the control level at 10 uM, to 3.6-fold at 50 uM and to 4.7-fold at 75 uM. Conclusion: These results indicate that activation of PPAR-gamma with troglitazone induces apoptosis through cell cycle inhibition in estrogen receptor-negative breast cancer cell MDA-MB-231. PPAR-gamma therefore represents a putative molecular target for chemopreventive therapy or inhibition of breast cancer growth.

No significant financial relationships to disclose.

Novel blood biomarker panel detects human colorectal cancer

3611

Background: Human colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States, and early detection is critical to improve prognosis. To date, we have applied our unique methodology (the Sentinel Principle) to identify blood-based gene expressed biomarkers for several diseases including osteoarthritis, bladder cancer and psychiatric disorders. In the present CRC study, we identified gene signatures from blood cells and characterized a set of biomarkers able to differentiate patients with CRC from controls. Methods: Microarray: 31 blood RNA sample (15 controls; 16 CRC) were profiled using Affymetrix U133Plus2.0 GeneChips. Differentially expressed genes were identified using the non-parametric, Wilcoxon-Mann-Whitney test. SYBR Green real-time RT-PCR: a subset of identified genes was assayed using 115 samples (57 controls; 58 CRC). Logistic regression was used to assess the ability of linear combinations of specific transcripts to distinguish CRC from controls. The diagnostic power for each combination was evaluated by AUC of the Receiver Operating Characteristic (ROC) curve. Blind Test: 83 samples were assayed (45 controls and 38 CRC). Results: Microarray data: 2,779 probes were significantly different in blood gene expression profiles from controls and those from CRC (p<0.05). Real-time RT-PCR: Two up-regulated genes (cytidine deaminase, 1.3 fold with p<0.001; MGC20553 /FERM domain containing 3, 1.2 fold with p=0.031) and three down-regulated genes were validated (B-cell scaffold protein with ankyrin repeats 1, 0.43 fold with p<0.001; B-cell novel protein 1, 0.44 fold with p<0.001; membrane-spanning 4-domains, subfamily A, member 1, 0.44 with p<0.001). Combination analysis: The AUC was 0.883 (95%, C.I. 0.810–0.935) for the best linear combination of these 5 genes. At a cut-off of -1.1, the sensitivity and specificity were 98% and 51%, respectively. Blind Test: The 5-gene set gave sensitivity of 95% (36/38) and specificity of 42% (19/45) with an overall accuracy of 66%. Conclusions: Gene expression signatures from peripheral blood differentiate between CRC patients and controls. The five-gene panel showed high classification performance and could be used as a novel screening tool for CRC.

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Over-expression, purification, and characterization of aminopeptidase N from Escherichia coli

The gene from Escherichia coli encoding aminopeptidase N (PepN) was subcloned into pET-26b, and PepN was over-expressed in BL21(DE3) E. coli and purified using Q-Sepharose chromatography. This protocol yielded over 17 mg of purified, recombinant PepN per liter of growth culture under optimum conditions. Gel filtration chromatography revealed that recombinant PepN exists as a monomer. MALDI-TOF mass spectra showed that the enzyme has a molecular mass of 98,750 Da, and steady-state kinetic studies revealed that as-isolated, recombinant PepN exhibits a k(cat) of 354 +/- 11s(-1) and a K(m) of 376 +/- 39 microM when using L-alanine-p-nitroanilide as the substrate. Metal analyses demonstrated that as-isolated, recombinant PepN binds 0.5 and <0.1 equivalents of iron and zinc, respectively. The addition of Zn(II) to recombinant PepN inhibits catalytic activity, while the addition of iron causes a slight decrease or no change in activity. Further metal binding studies revealed that recombinant PepN tightly binds 5 equivalents of iron and <0.1 equivalents of Zn(II). By using this over-expression and purification system, E. coli PepN can now be obtained in quantities necessary for structural characterization and possibly inhibitor design efforts.

Blood-based biomarkers for detecting mild osteoarthritis in the human knee

OBJECTIVE

This study was designed to test the utility of a blood-based approach to identify mild osteoarthritis (OA) of the knee.

METHODS

Blood samples were drawn from 161 subjects, including 85 subjects with arthroscopically diagnosed mild OA of the knee and 76 controls. Following RNA isolation, an in-house custom cDNA microarray was used to screen for differentially expressed genes. A subset of selected genes was then tested using real-time RT-PCR. Logistic regression analysis was used to evaluate linear combinations of the biomarkers and receiver operating characteristic curve analysis was used to assess the discriminatory power of the combinations.

RESULTS

Genes differentially expressed (3543 genes) between mild knee OA and control samples were identified through microarray analysis. Subsequent real-time RT-PCR verification identified six genes significantly down-regulated in mild OA: heat shock 90kDa protein 1, alpha; inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase complex-associated protein; interleukin 13 receptor, alpha 1; laminin, gamma 1; platelet factor 4 (also known as chemokine (C-X-C motif) ligand 4) and tumor necrosis factor, alpha-induced protein 6. Logistic regression analysis identified linear combinations of nine genes--the above six genes, early growth response 1; alpha glucosidase II alpha subunit; and v-maf musculoaponeurotic fibrosarcoma oncogene homolog B (avian)--as discriminatory between subjects with mild OA and controls, with a sensitivity of 86% and specificity of 83% in a training set of 78 samples. The optimal biomarker combinations were then evaluated using a blind test set (67 subjects) which showed 72% sensitivity and 66% specificity.

CONCLUSIONS

Linear combinations of blood RNA biomarkers offer a substantial improvement over currently available diagnostic tools for mild OA. Blood-derived RNA biomarkers may be of significant clinical value for the diagnosis of early, asymptomatic OA of the knee.