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1.  Universal Order Parameters and Quantum Phase Transitions: A Finite-Size Approach 
Scientific Reports  2015;5:7673.
We propose a method to construct universal order parameters for quantum phase transitions in many-body lattice systems. The method exploits the H-orthogonality of a few near-degenerate lowest states of the Hamiltonian describing a given finite-size system, which makes it possible to perform finite-size scaling and take full advantage of currently available numerical algorithms. An explicit connection is established between the fidelity per site between two H-orthogonal states and the energy gap between the ground state and low-lying excited states in the finite-size system. The physical information encoded in this gap arising from finite-size fluctuations clarifies the origin of the universal order parameter. We demonstrate the procedure for the one-dimensional quantum formulation of the q-state Potts model, for q = 2, 3, 4 and 5, as prototypical examples, using finite-size data obtained from the density matrix renormalization group algorithm.
PMCID: PMC4286789  PMID: 25567585
2.  Comparison of Outcomes After Fluorouracil-Based Adjuvant Therapy for Stages II and III Colon Cancer Between 1978 to 1995 and 1996 to 2007: Evidence of Stage Migration From the ACCENT Database 
Journal of Clinical Oncology  2013;31(29):3656-3663.
With improved patient care, better diagnosis, and more treatment options after tumor recurrence, outcomes after fluorouracil (FU) -based treatment are expected to have improved over time in early-stage colon cancer. Data from 18,449 patients enrolled onto 21 phase III trials conducted from 1978 to 2002 were evaluated for potential differences in time to recurrence (TTR), time from recurrence to death (TRD), and overall survival (OS) with regard to FU-based adjuvant regimens.
Trials were predefined as old versus newer era using initial accrual before or after 1995. Outcomes were compared between patients enrolled onto old- or newer-era trials, stratified by stage.
Within the first 3 years, recurrence rates were lower in newer- versus old-era trials for patients with stage II disease, with no differences among those with stage III disease. Both TRD and OS were significantly longer in newer-era trials overall and within each stage. The lymph node (LN) ratio (ie, number of positive nodes divided by total nodes harvested) in those with stage III disease declined over time. TTR improved slightly, with larger number of LNs examined in both stages.
Improved TRD in newer trials supports the premise that more aggressive intervention (oxaliplatin- and irinotecan-based chemotherapy and/or surgery for recurrent disease) improves OS for patients previously treated in the adjuvant setting. Lower recurrence rates with identical treatments in those with stage II disease enrolled onto newer-era trials reflect stage migration over time, calling into question historical data related to the benefit of FU-based adjuvant therapy in such patients.
PMCID: PMC3804289  PMID: 23980089
3.  The Predictive and Prognostic Value of Sex in Early-Stage Colon Cancer: A Pooled Analysis of 33,345 Patients from the ACCENT Database 
Clinical colorectal cancer  2013;12(3):179-187.
Our study compares the outcomes of men and women with early stage colon cancer by analyzing the ACCENT database. Overall, men experienced inferior prognoses when compared with women for time to recurrence after adjusting for age, stage, and treatment. Sex was not a predictive factor of treatment efficacy. In exploratory analyses, worse outcomes in men were more prominent in older patients, but the stage of disease and type of adjuvant regimen did not modify the prognostic value of sex.
To compare long-term outcomes between men and women in a large cohort of clinical trial participants with early-stage colon cancer, specifically by examining whether the prognostic effect of sex varies based on age, stage of disease, and type of adjuvant therapy received.
A pooled analysis of individual patient data from 33,345 patients with colon cancer enrolled in 24 phase III studies of various adjuvant systemic therapies was conducted. Chemotherapy consisted of (1) fluorouracil (5-FU), (2) 5-FU variations, (3) 5-FU plus oxaliplatin, (4) 5-FU plus irinotecan, or (5) oral fluoropyrimidine-based regimens. The primary endpoint was disease-free survival; secondary endpoints included overall survival and time to recurrence. Stratified Cox models were used to assess the effect of sex on outcomes. Multivariate models were used to assess adjusted effects and to explore the interaction among sex and other factors.
A total of 18,244 (55%) men and 15,101 (45%) women were included. In the entire cohort, the median age was 61 years; 91% (24,868) were white; 31% (10,347) and 69% (22,964) had stage I/II and III disease, respectively. Overall, men had inferior prognoses when compared with women for time to recurrence (hazard ratio [HR] 1.05 [95% CI, 1.01–1.09]) and other endpoints after adjusting for age, stage, and treatment. Sex was not a predictive factor of treatment efficacy (P for interaction between sex and treatment when adjusting for age and stage were .40, .67, and .77 for disease-free survival, overall survival, and time to recurrence, respectively). In exploratory analyses, worse outcomes in men were more prominent in the older patients when adjusting for stage and treatment (HR 1.08 in age ≤ 65 years vs. HR 1.18 in age > 65 years; interaction P = .016 for disease-free survival). The stage of disease and type of adjuvant regimen did not modify the prognostic value of sex.
Sex is a modest independent prognostic marker for patients with early-stage colon cancer, particularly in older patients.
PMCID: PMC3760214  PMID: 23810482
Sex; Colon cancer; Survival; Outcomes
4.  Mutation-Specific Antibody Detects Mutant BRAFV600E Protein Expression in Human Colon Carcinomas 
Cancer  2013;119(15):2765-2770.
A point mutation (V600E) in the BRAF oncogene is a prognostic biomarker and may predict for non response to anti-EGFR antibody therapy in colon carcinomas. BRAFV600E mutations are also frequently detected in tumors with microsatellite instability and indicate a sporadic origin. Using a mutation-specific antibody, we examined mutant BRAFV600E protein expression and its concordance with BRAFV600E mutation data.
Resected, primary stage III colon carcinomas were analyzed for BRAFV600E mutations in exon 15, and 50 BRAFV600E mutation carriers and 25 wild-type cases were selected for immunohistochemistry (IHC). IHC was performed in archival tissue specimens using a pan-BRAF antibody and a mutation-specific antibody against BRAFV600E proteins. Staining was scored by two pathologists blinded to clinical and mutation data.
Using a pan-BRAF antibody, total BRAF protein expression was observed in the tumor cell cytoplasm in 74 of 75 colon carcinomas. A mutation-specific antibody identified diffuse cytoplasmic staining of mutant BRAFV600E proteins in 49 of 74 cancers. All 49 of these cases were shown to carry BRAFV600E mutations by a PCR-based assay. In contrast, BRAFV600E staining was absent in all 25 tumors found to carry wild-type copies of BRAFV600E.
A BRAF mutation-specific (V600E) antibody detects tumors with BRAFV600E mutations and shows complete concordance with a DNA-based method. These results support the use of IHC as a simplified strategy to screen colorectal cancers for mutant BRAFV600E proteins in clinical practice.
PMCID: PMC3720760  PMID: 23657789
colon cancer; BRAFV600E mutation; immunohistochemistry; MSI; BRAFV600E protein
5.  Statistical evaluation of the use of concurrent controls in treatment screening studies 
A well-designed pilot study can advance science by providing essential preliminary data to support or motivate further research, refine study logistics, and demonstrate proof of concept. Often, the outcomes of such studies can be quantified by a success/failure dichotomy. For example, a novel compound may show activation of a neural pathway, or it may not. When an intervention’s efficacy is quantified using a dichotomous outcome, probability mass functions can be enumerated to determine the probability that the observed result from a pilot study supports further evaluation of the intervention since there is only a finite, and often small, number of sample configurations possible. The purpose of this research was to determine the probability of an ‘efficacy signal’ for pilot studies using one- and two-sample pilot study designs. Efficacy signal was defined as the probability of observing a more favorable response proportion relative to a historical control (one-sample setting) or to a concurrent control (two-sample setting). An enumeration study (exact simulation) was conducted to calculate the efficacy signal probability. One-sample study designs yielded higher probability of determining an efficacy signal than the two-sample setting; however, sampling variation must be accounted for. A 68% score confidence interval is recommended for this purpose.
PMCID: PMC3740457  PMID: 23919371
pilot study; randomization; study design; confidence interval
6.  Associations Between Cigarette Smoking Status and Colon Cancer Prognosis Among Participants in North Central Cancer Treatment Group Phase III Trial N0147 
Journal of Clinical Oncology  2013;31(16):2016-2023.
By using data from North Central Cancer Treatment Group Phase III Trial N0147, a randomized adjuvant trial of patients with stage III colon cancer, we assessed the relationship between smoking and cancer outcomes, disease-free survival (DFS), and time to recurrence (TTR), accounting for heterogeneity by patient and tumor characteristics.
Patients and Methods
Before random assignment to infusional fluorouracil, leucovorin, and oxaliplatin (FOLFOX) or FOLFOX plus cetuximab, 1,968 participants completed a questionnaire on smoking history and other risk factors. Cox models assessed the association between smoking history and the primary trial outcome of DFS (ie, time to recurrence or death), as well as TTR, adjusting for other clinical and patient factors. The median follow-up was 3.5 years among patients who did not experience events.
Compared with never-smokers, ever smokers experienced significantly shorter DFS (3-year DFS proportion: 70% v 74%; hazard ratio [HR], 1.21; 95% CI, 1.02 to 1.42). This association persisted after multivariate adjustment (HR, 1.23; 95% CI, 1.02 to 1.49). There was significant interaction in this association by BRAF mutation status (P = .03): smoking was associated with shorter DFS in patients with BRAF wild-type (HR, 1.36; 95% CI, 1.11 to 1.66) but not BRAF mutated (HR, 0.80; 95% CI, 0.50 to 1.29) colon cancer. Smoking was more strongly associated with poorer DFS in those with KRAS mutated versus KRAS wild-type colon cancer (HR, 1.50 [95% CI, 1.12 to 2.00] v HR, 1.09 [95% CI, 0.85 to 1.39]), although interaction by KRAS mutation status was not statistically significant (P = .07). Associations were comparable in analyses of TTR.
Overall, smoking was significantly associated with shorter DFS and TTR in patients with colon cancer. These adverse relationships were most evident in patients with BRAF wild-type or KRAS mutated colon cancer.
PMCID: PMC3661936  PMID: 23547084
7.  HER-2/neu Gene Amplification in Relation to Expression of HER2 and HER3 Proteins in Patients With Esophageal Adenocarcinoma 
Cancer  2013;120(3):415-424.
Human epidermal growth factor receptor 2 (HER2) is a therapeutic target in patients with esophageal adenocarcinoma (EAC), with gene amplification used as a selection criterion for treatment, although to the authors’ knowledge the concordance between amplification and HER2 protein expression remains undefined in EAC. Furthermore, the association between HER2 and its interacting partner, human epidermal growth factor receptor 3 (HER3), is unknown yet appears to be of potential therapeutic relevance.
Patients with untreated EACs (N 5 673) were analyzed for HER2 amplification and polysomy 17 by fluorescence in situ hybridization in parallel with immunohistochemistry (IHC) (IHC scores of 0–1+, 2+, and 3+). Amplification was defined as HER2=CEP17 ≥2. HER3 expression by IHC was analyzed in randomly selected cases (n 5 224). IHC and fluorescence in situ hybridization results were compared using least squares linear regression.
Overall, 17% of the EACs (116 of 673 EACs) were HER2-amplified with an amplification frequency that was highest among IHC3+ cases (89%) and declined among IHC2+ cases (13%) and IHCO to IHC1+ cases (4%). Among HER2-amplified cases, the level of amplification increased linearly with HER2 membranous expression (HER2/CEP17 ratio: 7.9 in IHC3+ and 5.5 in IHC2+ vs 2.8 in IHCO to IHC11 [P<.0001]), with 14% of amplified tumors demonstrating absent/faint expression (IHCO to IHC1+). Polysomy 17 was not found to be associated with HER2 expression. Cytoplasmic HER3 expression was detected in 87% of tumors (195 of 224 tumors) and was found to be significantly associated with better differentiation (P<.0001). Stepwise increases in HER3 expression were associated with higher HER2 expression levels (P = .0019).
Levels of HER2 protein expression and amplification were found to be linearly associated and highly concordant. Among amplified tumors with absent/faint expression, the level of amplification was low. Frequent expression of HER3 suggests its relevance as a therapeutic target, and its significant association with HER2 supports ongoing efforts to inhibit HER2/HER3 in patients with EAC.
PMCID: PMC3932765  PMID: 24151090
human epidermal growth factor receptor 2 (HER2); ERBB2; concordance; fluorescence in situ hybridization; HER2 gene amplification; HER2 expression; HER3/ERBB3; esophageal cancer; esophageal adenocarcinoma; esophagogastric cancer
8.  Adverse Prognostic Impact of Intratumor Heterogeneous HER2 Gene Amplification in Patients With Esophageal Adenocarcinoma 
Journal of Clinical Oncology  2012;30(32):3932-3938.
There is increasing recognition of the existence of intratumoral heterogeneity of the human epidermal growth factor receptor (HER2), which affects interpretation of HER2 positivity in clinical practice and may have implications for patient prognosis and treatment. We determined the frequency and prognostic impact of heterogeneous HER2 gene amplification and polysomy 17 in patients with esophageal adenocarcinoma (EAC).
Patients and Methods
HER2 amplification (by fluorescence in situ hybridization) was examined in surgical EAC specimens (n = 675). HER2 heterogeneity was defined according to consensus guidelines as gene amplification (HER2/CEP17 ratio ≥ 2.0) in more than 5% but less than 50% of cancer cells. No patient received neoadjuvant or HER2-targeted therapy. Cox models were used to assess disease-specific survival (DSS) and overall survival (OS).
Overall, 117 EACs (17%) demonstrated HER2 amplification, of which 20 (17%) showed HER2 heterogeneity. All HER2-heterogeneous tumors were amplified. Among HER2-amplified tumors, heterogeneous tumors had significantly higher frequency of poor histologic grade and polysomy 17. In multivariable models that included number of metastatic lymph nodes, grade, tumor stage, and polysomy 17, only HER2 heterogeneity and node number were prognostic among HER2-amplified tumors, with heterogeneity showing worse DSS (hazard ratio, 2.04; 95% CI, 1.09 to 3.79; P = .025) and OS (P = .026). Among HER2-nonamplified EACs, polysomy 17 was independently associated with worse DSS (P = .012) and OS (P = .023).
Among HER2-amplified EACs, 17% show HER2 heterogeneity, which independently predicts for worse cancer-specific death. Among HER2-nonamplified EACs, polysomy 17 is independently associated with worse survival. These novel findings demonstrate aggressive subgroups in HER2-amplified and -nonamplified EACs that have important implications for HER2 analysis and determination of benefit from HER2-targeted therapy.
PMCID: PMC3675687  PMID: 22987085
9.  Combination of Human Leukocyte Antigen and Killer Cell Immunoglobulin-Like Receptor Genetic Background Influences the Onset Age of Hepatocellular Carcinoma in Male Patients with Hepatitis B Virus Infection 
To investigate whether killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) genetic background could influence the onset age of hepatocellular carcinoma (HCC) in patients with hepatitis B virus (HBV) infection, one hundred and seventy-one males with HBV-related HCC were enrolled. The presence of 12 loci of KIR was detected individually. HLA-A, -B, and -C loci were genotyped with high resolution by a routine sequence-based typing method. The effect of each KIR locus, HLA ligand, and HLA-KIR combination was examined individually by Kaplan-Meier (KM) analysis. Multivariate Cox hazard regression model was also applied. We identified C1C1-KIR2DS2/2DL2 as an independent risk factor for earlier onset age of HCC (median onset age was 44 for C1C1-KIR2DS2/2DL2 positive patients compared to 50 for negative patients, P = 0.04 for KM analysis; HR = 1.70, P = 0.004 for multivariate Cox model). We conclude that KIR and HLA genetic background can influence the onset age of HCC in male patients with HBV infection. This study may be useful to improve the current HCC surveillance program in HBV-infected patients. Our findings also suggest an important role of natural killer cells (or other KIR-expressing cells) in the progress of HBV-related HCC development.
PMCID: PMC3842051  PMID: 24312130
10.  Antitumor Agents 295. E-ring Hydroxylated Antofine and Cryptopleurine Analogs as Antiproliferative Agents: Design, Synthesis, and Mechanistic Studies 
Journal of medicinal chemistry  2012;55(15):6751-6761.
Various E-ring hydroxylated antofine and cryptopleurine analogs were designed, synthesized, and tested against five human cancer cell lines. Interesting structure-activity relationship (SAR) correlations were found among these new compounds. The most potent compound 13b was further tested against a series of non-small cell lung cancer (NSCLC) cell lines, in which it showed impressive antiproliferative activity. Mechanistic studies revealed that 13b is able to down-regulate HSP90 and β-catenin in A549 lung adenocarcinoma cells in a dose-dependent manner, suggesting a potential use for treating Hedgehog pathway-driven tumorigenesis.
PMCID: PMC3422873  PMID: 22823514
11.  Antitumor agents 294. Novel E-ring-modified camptothecin–4β-anilino-4′-O-demethylepipodophyllotoxin conjugates as DNA topoisomerase I inhibitors and cytotoxic agents 
Bioorganic & medicinal chemistry  2012;20(14):4489-4494.
Two conjugates (1 and 2) of camptothecin (CPT) and 4β-anilino-4′-O-demethylepipodophyllotoxin were previously shown to exert antitumor activity through inhibition of topoisomerase I (topo I). In this current study, two novel conjugates (1E and 2E) with an open E-ring in the CPT moiety were first synthesized and evaluated for biological activity in comparison with their intact E-ring congeners. This novel class of CPT derivatives exhibits its antitumor effect against CPT-sensitive and -resistant cells, in part, by inhibiting topo I-linked DNA (TLD) religation. An intact E-ring was not essential for the inhibition of TLD religation, although conjugates with an open E-ring were less potent than the closed ring analogs. This lower religation potency resulted in decreased formation of protein-linked DNA breaks (PLDBs), and hence, less cell growth inhibition. In addition to their impact on topo I, conjugates 1E, 2, and 2E exhibited a minor inhibitory effect on topo II-induced DNA cleavage. The novel structures of 1E and 2E may present scaffolds for further development of dual function topo I and II inhibitors with improved pharmacological profiles and physicochemical properties.
PMCID: PMC3389137  PMID: 22698783
Topoisomerase; cytotoxicity; camptothecin (CPT); etoposide (VP-16); epipodophyllotoxin; conjugates
12.  Antitumor agents 290. † Design, synthesis, and biological evaluation of new LNCaP and PC-3 cytotoxic curcumin analogs conjugated with anti-androgens 
Bioorganic & medicinal chemistry  2012;20(13):4020-4031.
In our continuing study of curcumin analogs as potential anti-prostate cancer drug candidates, 15 new curcumin analogs were designed, synthesized and evaluated for cytotoxicity against two human prostate cancer cell lines, androgen-dependent LNCaP and androgen-independent PC-3. Twelve analogs (5-12, 15, 16, 19, and 20) are conjugates of curcumin (1) or methyl curcumin (2) with a flutamide- or bicalutamide-like moiety. Two compounds (22 and 23) are C4-mono- and difluoro-substituted analogs of dimethyl curcumin (DMC, 21). Among the newly synthesized conjugates compound 15, a conjugate of 2 with a partial bicalutamide moiety, was more potent than bicalutamide alone and essentially equipotent with 1 and 2 against both prostate tumor cell lines with IC50 values of 41.8 μM (for LNCaP) and 39.1 μM (for PC-3). A cell morphology study revealed that the cytotoxicity of curcumin analogs or curcumin-antiandrogen conjugates detected from both prostate cancer cell lines might be due to the suppression of pseudopodia formation. A molecular intrinsic fluorescence experiment showed that 1 accumulated mainly in the nuclei, while conjugate 6 was distributed in the cytosol. At the tested conditions, antiandrogens suppressed pseudopodia formation in PC-3 cells, but not in LNCaP cells. The evidence suggests that distinguishable target proteins are involved, resulting in the different outcomes toward pseudopodia suppression.
PMCID: PMC3376200  PMID: 22672984
Synthesis; Curcumin analogs; Conjugates; Cytotoxicity; Anti-prostate cancer; Morphology
13.  Distribution of Body Fat and its Influence on Esophageal Inflammation and Dysplasia in Patients with Barrett's Esophagus 
Background & Aims
Increased waist circumference and visceral fat are associated with increased risk of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). This association might be mediated by mechanical and endocrine mechanisms. We investigated the distribution of fat in subjects with BE and its association with esophageal inflammation and dysplasia.
We collected data from 50 BE cases and 50 controls (matched for age and sex, identified from a radiology trauma database) seen at the Mayo Clinic in 2009. Abdominal (subcutaneous and visceral) and gastroesophageal junction (GEJ) fat area was measured using computed tomography with standard techniques. Esophageal inflammation (based on a histological score) and dysplasia grade were assessed from esophageal biopsies of BE cases by a gastrointestinal pathologist. Conditional logistic regression was used to assess the association of body fat depot area with BE status, esophageal inflammation and dysplasia.
All BE subjects had controlled reflux symptoms without esophagitis, based on endoscopy. GEJ fat area (odds ratio [OR], 6.0; 95% confidence interval [CI], 1.3–27.7; P=.02), visceral fat area (OR, 4.9; 95% CI, 1.0–22.8; P=.04) and abdominal circumference (OR=9.1; 95% CI, 1.4–57.2; P=0.02) were associated with BE, independent of BMI. Subcutaneous fat area was not associated with BE. Visceral and GEJ fat were significantly greater in BE subjects with esophageal inflammation (compared to those without, P=.02) and high-grade dysplasia (HGD) (compared to those without, P=.01), independent of BMI.
GEJ and visceral fat are associated with BE, and with increased esophageal inflammation and HGD in BE subjects, independent of BMI. Visceral fat might therefore promote esophageal metaplasia and dysplasia.
PMCID: PMC3381999  PMID: 22433923
Barrett's Esophagus; Central Obesity; Inflammation; Dysplasia; CT imaging; risk factor; esophageal carcinoma; obesity
14.  Benefits and Adverse Events in Younger Versus Older Patients Receiving Adjuvant Chemotherapy for Colon Cancer: Findings From the Adjuvant Colon Cancer Endpoints Data Set 
Journal of Clinical Oncology  2012;30(19):2334-2339.
Limited data exist regarding the outcomes of adjuvant therapy in younger patients with stage II and III colon cancer. We examined disease-free survival (DFS), overall survival (OS), recurrence-free interval (RFI), and grade 3+ adverse events (AEs) in younger patients in the 33,574 patient Adjuvant Colon Cancer Endpoints Group data set.
Patients and Methods
Individual patient data from 24 randomized phase III clinical trials were obtained for survival outcomes, which included 10 clinical trials for AE outcomes. Two age-based cutoff points were used to define younger patients: age younger than 40 years and younger than 50 years. Adjuvant therapy benefit analyses were limited to the nine clinical trials in which the investigational chemotherapeutic arm demonstrated benefit.
One thousand seven hundred fifty-eight patients (5.2%) were younger than 40 years, 5,817 patients (17.3%) were younger than 50 years, and only 299 patients (0.9%) were younger than 30 years. No meaningful differences in sex or stage were noted in younger versus older patients. Younger and older patients did not differ in RFI (age, < 40 years: hazard ratio [HR], 1.0; P = .62 and age < 50 years: HR, 1.02; P = .35). Younger patients (both cutoff points), had longer OS and DFS than older patients. In trials demonstrating adjuvant therapy benefit, similar DFS benefit was observed by age. Younger patients experienced less leukopenia and stomatitis, but more frequent nausea/vomiting.
Among patients on clinical trials, younger and older patients with stage II and III colon cancer had similar RFI and adjuvant therapy benefit. Younger patients have longer OS and DFS, which is likely primarily because of fewer competing causes of death. Adjuvant therapy is beneficial for colon cancer in patients younger than 50 years who meet typical clinical trial eligibility criteria.
PMCID: PMC3675692  PMID: 22614981
15.  Anti-AIDS agents 89. Identification of DCX derivatives as anti-HIV and chemosensitizing dual function agents to overcome P-gp-mediated drug resistance for AIDS therapy 
In this study, 19 dicamphanoyl-dihydropyranochromone (DCP) and dicamphanoyl-dihydropyranoxanthone (DCX) derivatives, previously discovered as novel anti-HIV agents, were evaluated for their potential to reverse multi-drug resistance (MDR) in a cancer cell line over-expressing P-glycoprotein (P-gp). Seven compounds fully reversed resistance to vincristine (VCR) at 4 μM, a 20-fold enhancement compared to the first generation chemosensitizer, verapamil (4 μM). The mechanism of action of DCPs and DCXs was also resolved, since the most active compounds (3, 4, and 7) significantly increased intracellular drug accumulation due, in part, to inhibiting the P-gp mediated drug efflux from cells. We conclude that DCPs (3 and 4) and DCXs (7, 11, and 17) can exhibit polypharmacologic behavior by acting as dual inhibitors of HIV replication and chemoresistance mediated by P-gp. As such, they may be useful in combination therapy to overcome P-gp-associated drug resistance for AIDS treatment.
PMCID: PMC3331909  PMID: 22465634
pyranochromone derivatives; chemoresistance; P-glycoprotein (P-gp) inhibitors; anti-HIV agents; dual function inhibitors
16.  Treatment of Colorectal Peritoneal Carcinomatosis With Systemic Chemotherapy: A Pooled Analysis of North Central Cancer Treatment Group Phase III Trials N9741 and N9841 
Journal of Clinical Oncology  2011;30(3):263-267.
Symptoms and complications of metastatic colorectal cancer (mCRC) differ by metastatic sites. There is a paucity of prospective survival data for patients with peritoneal carcinomatosis colorectal cancer (pcCRC). We characterized outcomes of patients with pcCRC enrolled onto two prospective randomized trials of chemotherapy and contrasted that with other manifestations of mCRC (non-pcCRC).
A total of 2,095 patients enrolled onto two prospective randomized trials were evaluated for overall survival (OS) and progression-free survival (PFS). A Cox proportional hazard model was used to assess the adjusted associations.
The characteristics of the pcCRC group (n = 364) were similar to those of the non-pcCRC patients in median age (63 v 61 years, P = .23), sex (57% males v 61%, P = .23), and performance status (Eastern Cooperative Oncology Group performance status 0 or 1 94% v 96%, P = .06), but differed in frequency of liver (63% v 82%, P < .001) and lung metastases (27% v 34%, P = .01). Median OS (12.7 v 17.6 months, hazard ratio [HR] = 1.3; 95% CI, 1.2 to 1.5; P < .001) and PFS (5.8 v 7.2 months, HR = 1.2; 95% CI, 1.1 to 1.3; P = .001) were shorter for pcCRC versus non-pcCRC. The unfavorable prognostic influence of pcCRC remained after adjusting for age, PS, liver metastases, and other factors (OS: HR = 1.3, P < .001; PFS: HR = 1.1, P = .02). Infusional fluorouracil, leucovorin, and oxaliplatin was superior to irinotecan, leucovorin, and fluorouracil as a first-line treatment among pcCRC (HR for OS = 0.62, P = .005) and non-pcCRC patients (HR = 0.66, P < .001).
pcCRC is associated with a significantly shorter OS and PFS as compared with other manifestations of mCRC. Future trials for mCRC should consider stratifying on the basis of pcCRC status.
PMCID: PMC3269953  PMID: 22162570
17.  Association of HER2/ErbB2 Expression and Gene Amplification with Pathological Features and Prognosis in Esophageal Adenocarcinomas 
Clinical Cancer Research  2012;18(2):546-554.
We examined the frequency, tumor characteristics, and prognostic impact of HER2 protein expression and gene amplification in patients with curatively resected esophageal adenocarcinoma (EAC).
Experimental Design
HER2 expression was analyzed by immunohistochemistry (IHC) in surgical EAC specimens (n=713). Gene amplification was examined by fluorescence in situ hybridization (FISH) in a large subset (n=344). Most tumors were T3–4 (66%) or node-positive (72%); 95% were located in the esophagus or gastroesophageal junction. No patient received neoadjuvant therapy. Cox models were used.
Overall, 17% of EACs were HER2-positive (ie, IHC3+ or IHC2+ with amplification), with strong agreement between HER2 amplification (HER2/CEP17 ratio ≥2) and expression (κ=.83). HER2-positivity was significantly associated with lower tumor grade, less invasiveness, fewer malignant nodes, and the presence of adjacent Barrett’s esophagus (BE). EACs with BE had higher odds of HER2-positivity compared to EACs without BE, independent of pathologic features (odds ratio 1.8 [95% confidence interval (CI) 1.1–2.8], p=.014). Among all cases, HER2-positivity was significantly associated with disease-specific survival (DSS) in a manner that differed by the presence or absence of BE (p for interaction=.0047). In EACs with BE, HER2-positivity was significantly associated with improved DSS (hazard ratio 0.54 [95% CI 0.35–0.84], p=.0065) and overall survival (p=.0022) independent of pathologic features, but was not prognostic among EACs without BE.
HER2-positivity was demonstrated in 17% of resected EACs and associated with reduced tumor aggressiveness. EACs with BE had nearly twice the odds of being HER2-positive and, within this subgroup, HER2-positivity was independently associated with improved survival.
PMCID: PMC3261584  PMID: 22252257
esophageal adenocarcinoma; Barrett’s esophagus; HER2; ErbB2; prognosis
18.  Anti-AIDS agents 85. Design, synthesis, and evaluation of 1R,2R-dicamphanoyl-3,3-dimethyldihydropyrano-[2,3-c]xanthen-7(1H)-one (DCX) derivatives as novel anti-HIV agents 
In this study, 1R,2R-dicamphanoyl-3,3-dimethydihydropyrano[2,3-c]xanthen-7(1H)-one (DCX) derivatives were designed and synthesized as novel anti-HIV agents against both wild-type and nonnucleoside reverse transcriptase (RT) inhibitor-resistant HIV-1 (RTMDR-1) strains. Twenty-four DCX analogs (6-29) were synthesized and evaluated against the non-drug-resistant HIV-1 NL4-3 strain, and selected analogs were also screened for their ability to inhibit the RTMDR-1 strain. Compared with the control 2-ethyl-3′,4′-di-O-(-)-camphanoyl-2′,2′-dimethyldihydropyrano[2,3-f]chromone (2-EDCP, 2), one of the best anti-HIV coumarin derivatives in our prior study, three DCX compounds (7, 12, and 22) showed better activity against both HIV strains with an EC50 range of 0.062 – 0.081 μM, and five additional compounds (8, 11, 16, 18, and 21) exhibited comparable anti-HIV potency. Six DCX analogs (7, 11-12, 18, and 21-22) also showed enhanced selectivity index (SI) values in comparison to the control. Structure-activity relationship (SAR) information suggested that the extended conjugated system of the pyranoxanthone skeleton facilitates the interaction of the small DCX molecule within the viral binding pocket, consequently leading to enhanced anti-HIV activity and selectivity. Compared to DCP compounds, DCX analogs are a more promising new class of anti-HIV agents.
PMCID: PMC3259201  PMID: 22063755
1R,2R-dicamphanoyl-3,3-dimethydihydropyrano[2,3-c]xanthen-7(1H)-one (DCX); Anti-HIV activity; Structure-activity relationship (SAR)
19.  Cryptopleurine Analogs with Modification of E Ring Exhibit Different Mechanism to Rac-Cryptopleurine and Tylophorine 
PLoS ONE  2012;7(12):e51138.
Tylophorine analogs exhibit a broad range of pharmacological activities, including anti-cancer, anti-inflammatory, anti-autoimmune, and anti-virus effects. Structure-activity relationship study of different structure tylophorine analogs can provide further understanding of their biological activity. Modifications on the E ring of the quinolizidine moiety of cryptopleurine analogs changed the potency and the selective inhibitory effect on NF-κB, AP-1, and CRE signaling pathways. Functional cryptopleurine analogs showed potent inhibition of NF-κB signaling pathway in both HepG2 and HEK-293 cell lines. The E ring structure analogs also differed in suppression of protein translation, and expression of cyclin D1. Our results showed that DCB-3503 or Rac-cryptopleurine could be a scaffold for modification to yield compounds with different mechanisms of action.
PMCID: PMC3519526  PMID: 23251437
20.  Prognostic Impact of Body Mass Index Stratified by Smoking Status in Patients With Esophageal Adenocarcinoma 
Journal of Clinical Oncology  2011;29(34):4561-4567.
Given that smoking affects body mass index (BMI) and survival, stratification by smoking status may be required to determine the true prognostic impact of BMI. Although obesity increases risk for developing esophageal adenocarcinoma (EAC), the prognostic influence of obesity and its potential modification by smoking status is unknown in this disease.
Patients and Methods
All patients (N = 778) underwent potentially curative esophagectomy. BMI was calculated using measured height and weight at surgery and categorized as obese (≥ 30 kg/m2), overweight (25 to 29.9 kg/m2), or normal (18.5 to 24.9 kg/m2). Cigarette smoking was categorized as never or ever. The association of BMI with disease-specific survival (DSS), disease-free survival (DFS), and overall survival (OS) was determined by Cox regression.
Excess BMI was significantly associated with DSS in a manner that differed substantially by smoking status (P for interaction = .023). Among never smokers, obesity was significantly associated with adverse DSS (hazard ratio [HR] = 2.11; 95% CI, 1.31 to 3.43; P = .002), DFS (HR = 2.03; 95% CI, 1.30 to 3.18; P = .002), and OS (HR = 1.97; 95% CI, 1.24 to 3.14; P = .004), as compared with normal weight, after adjusting for covariates. By contrast, among ever smokers, obesity was not prognostic, and overweight status was significantly associated with favorable survival in univariate, but not multivariate, analysis.
Obesity among never smokers was independently associated with two-fold worsening of DSS, DFS, and OS after surgery for EAC, after adjusting for known prognostic factors. These data, in one of the largest reported resected EAC cohorts, are the first to show an adverse prognostic impact of obesity in EAC.
PMCID: PMC3236656  PMID: 21990414
21.  The Relationship of the Intensity of Posttreatment Prostate-Specific Antigen Surveillance and Prostate Cancer Outcomes: Results From a Population-Based Cohort 
Mayo Clinic Proceedings  2012;87(6):540-547.
To determine whether higher intensity of prostate-specific antigen (PSA) surveillance was associated with earlier detection of biochemical recurrence (BCR) or survival.
Patients and Methods
We identified a population-based cohort of 832 men diagnosed with nonmetastatic prostate cancer between January 1, 1995, and July 31, 2006. These men were treated with radical prostatectomy (RP), brachytherapy or external beam radiation therapy (RT), or primary androgen deprivation therapy or chose watchful waiting. To test the associations of intensity in PSA surveillance with study outcomes, we used a 2-year landmark analysis to assess whether the number of PSA tests during the first 2 years after treatment was associated with earlier detection of BCR, prostate cancer–related mortality, and all-cause mortality. We used landmark analysis to assess the association of PSA intensity, adjusting for clinicopathologic covariate, with outcome.
Median follow-up time for the entire cohort was 6.7 years. Higher Gleason score was the only clinicopathologic variable associated with higher PSA frequency in multivariable analysis for both the RP and RT groups (P value of .001 and .05, respectively). After adjustment for other covariates, the frequency of PSA tests during the first 2 years after RP did not increase the ability to detect BCR (hazard ratio, 1.00; 95% confidence interval, 0.84-1.19) or all-cause mortality (hazard ratio, 0.95; 95% confidence interval, 0.70-1.30) in the landmark analysis.
Higher intensity of PSA surveillance during the 2 years after RP or RT did not improve earlier detection of BCR or survival. Evidence-based guidelines for PSA surveillance after primary treatment are needed.
PMCID: PMC3498058  PMID: 22677074
ACM, all-cause mortality; ADT, androgen deprivation therapy; BCR, biochemical recurrence; HR, hazard ratio; PCSM, prostate cancer–specific mortality; PSA, prostatic-specific antigen; RP, radical prostatectomy; RT, radiation therapy; WW, watchful waiting
22.  The DNA Replication Factor RFC1 Is Required for Interference-Sensitive Meiotic Crossovers in Arabidopsis thaliana 
PLoS Genetics  2012;8(11):e1003039.
During meiotic recombination, induced double-strand breaks (DSBs) are processed into crossovers (COs) and non-COs (NCO); the former are required for proper chromosome segregation and fertility. DNA synthesis is essential in current models of meiotic recombination pathways and includes only leading strand DNA synthesis, but few genes crucial for DNA synthesis have been tested genetically for their functions in meiosis. Furthermore, lagging strand synthesis has been assumed to be unnecessary. Here we show that the Arabidopsis thaliana DNA REPLICATION FACTOR C1 (RFC1) important for lagging strand synthesis is necessary for fertility, meiotic bivalent formation, and homolog segregation. Loss of meiotic RFC1 function caused abnormal meiotic chromosome association and other cytological defects; genetic analyses with other meiotic mutations indicate that RFC1 acts in the MSH4-dependent interference-sensitive pathway for CO formation. In a rfc1 mutant, residual pollen viability is MUS81-dependent and COs exhibit essentially no interference, indicating that these COs form via the MUS81-dependent interference-insensitive pathway. We hypothesize that lagging strand DNA synthesis is important for the formation of double Holliday junctions, but not alternative recombination intermediates. That RFC1 is found in divergent eukaryotes suggests a previously unrecognized and highly conserved role for DNA synthesis in discriminating between recombination pathways.
Author Summary
Meiotic recombination is important for pairing and sustained association of homologous chromosomes (homologs), thereby ensuring proper homolog segregation and normal fertility. DNA synthesis is thought to be required for meiotic recombination, but few genes coding for DNA synthesis factors have been studied for possible meiotic functions because their essential roles in the mitotic cell cycle make it difficult to study their meiotic functions due to the lethality of corresponding null mutations. Current models for meiotic recombination only include leading strand DNA synthesis. We found that the Arabidopsis gene encoding the DNA REPLICATION FACTOR C1 (RFC1) important for lagging strand synthesis promotes meiotic recombination via a specific pathway for crossovers (COs) that involves the formation of double Holliday Junction (dHJ) intermediates. Therefore, lagging strand DNA synthesis is likely important for meiotic recombination. Because DNA synthesis is a highly conserved process and meiotic recombination is highly similar among budding yeast, mammals, and flowering plants, the proposed function of lagging strand synthesis for meiotic recombination might be a general feature of meiosis.
PMCID: PMC3493451  PMID: 23144629
23.  Glycyrrhetic Acid Synergistically Enhances β2-Adrenergic Receptor-Gs Signaling by Changing the Location of Gαs in Lipid Rafts 
PLoS ONE  2012;7(9):e44921.
Glycyrrhetic acid (GA) exerts synergistic anti-asthmatic effects via a β2-adrenergic receptor (β2AR)-mediated pathway. Cholesterol is an important component of the structure and function of lipid rafts, which play critical roles in the β2AR-Gs-adenylate cyclase (AC)-mediated signaling pathway. Owing to the structural similarities between GA and cholesterol, we investigated the possibility that GA enhances β2AR signaling by altering cholesterol distribution. Azide-terminal GA (ATGA) was synthesized and applied to human embryonic kidney 293 (HEK293) cells expressing fusion β2AR, and the electron spin resonance (ESR) technique was utilized. GA was determined to be localized predominantly on membrane and decreased their cholesterol contents. Thus, the fluidity of the hydrophobic region increased but not the polar surface of the cell membrane. The conformations of membrane proteins were also changed. GA further changed the localization of Gαs from lipid rafts to non-raft regions, resulting the binding of β2AR and Gαs, as well as in reduced β2AR internalization. Co-localization of β2AR, Gαs, and AC increased isoproterenol-induced cAMP production and cholesterol reloading attenuated this effect. A speculation wherein GA enhances beta-adrenergic activity by increasing the functional linkage between the subcomponents of the membrane β2AR-protein kinase A (PKA) signaling pathway was proposed. The enhanced efficacy of β2AR agonists by this novel mechanism could prevent tachyphylaxis.
PMCID: PMC3459958  PMID: 23028680
24.  Palmitoylation Regulates Intracellular Trafficking of β2 Adrenergic Receptor/Arrestin/Phosphodiesterase 4D Complexes in Cardiomyocytes 
PLoS ONE  2012;7(8):e42658.
β2 adrenergic receptor (β2AR) is a prototypical G-protein coupled receptor that stimulates the classic cAMP-protein kinase A (PKA) signaling pathway. Recent studies indicate that the cAMP-PKA activities are spatiotemporally regulated in part due to dynamic association of β2AR with phosphodiesterase 4D (PDE4D), a group of cAMP degradation enzymes. Here, we demonstrate that in cardiomyocytes, palmitoylation of β2AR, the covalent acylation of cysteine residue 341, plays a critical role in shaping subcellular cAMP-PKA activities in cardiomyocytes via regulating β2AR association with arrestin/PDE4D. Replacing cysteine 341 on β2AR with alanine (C341A) leads to an impaired binding to β arrestin 2. Surprisingly, the C341A mutant is able to internalize via an arrestin-independent pathway at saturated concentration of agonist stimulation; the internalization becomes caveolae-dependent and requires dynamin GTPase. However, the impaired binding to β arrestin 2 also leads to an impaired recruitment of PDE4D to the C341A mutant. Thus, the mutant C341A β2AR is transported alone from the plasma membrane to the endosome without recruiting PDE4D. This alteration leads to an enhanced cytoplasmic cAMP signal for PKA activation under β2AR stimulation. Functionally, Mutation of the C341 residue or inhibition of palmitoylation modification of β2AR enhances the receptor-induced PKA activities in the cytoplasm and increases in myocyte contraction rate. Our data reveal a novel function of palmitoylation in shaping subcellular cAMP-PKA signaling in cardiomyocytes via modulating the recruitment of β arrestin 2-PDE4D complexes to the agonist-stimulated β2AR.
PMCID: PMC3415400  PMID: 22912718
25.  Diaquadi-μ-formato-bis­{μ-2,2′-[propane-1,3-diylbis(nitrilo­methanylyl­idene)]diphenolato}cadmium(II)dinickel(II) dihydrate 
In the centrosymmetric title compound, [CdNi2(C17H16N2O2)2(HCOO)2(H2O)2]·2H2O, The NiII cation is chelated by a 2,2′-[propane-1,3-diylbis(nitrilo­methanylyl­idene)]diphen­olate (salpn) anion, and further coordinated by a formate anion and a water mol­ecule in a distorted NiN2O4 octa­hedral geometry. The CdII cation, located on an inversion center, is coordinated by four deprotonated hy­droxy groups from two salpn anions and two carboxyl­ate O atoms from formate anions in a distorted octa­hedral geometry. Both formate and salpn anions bridge the Cd and Ni cations, forming a trinuclear complex. Within the salpn anion, the benzene rings are twisted to each other at a dihedral angle of 61.46 (18)°. Inter­molecular O—H⋯O hydrogen bonding is present in the crystal structure. The lattice water mol­ecule is disorder over two positions with an occupancy ratio of 0.75:0.25.
PMCID: PMC3414165  PMID: 22904772

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