Haiyan Cui

Increased expression of thioredoxin-1 in human colorectal cancer is associated with decreased patient survival

Thioredoxin-1 is a redox protein that, when overexpressed, causes increased cancer-cell growth and inhibited apoptosis. Thioredoxin-1 expression has been reported to be increased in several human primary tumors, but its relationship to tumor progression and patient survival has not been established. We studied the expression of thioredoxin-1 as measured with immunohistochemical staining in paraffin-embedded human normal colonic mucosa, adenomatous polyps, and primary and metastatic colorectal cancer. Thioredoxin-1 expression was not increased in 12 colorectal adenomatous polyps, compared with 8 samples of normal colonic mucosa, but was significantly increased in 12 primary colorectal cancers (P <.01). Thioredoxin-1 expression was not significantly different in primary lymph-node metastases and the primary colorectal cancer. Using colorectal cancer samples from 37 subjects for whom survival data was available, we found that thioredoxin-1 expression increased with Dukes stage, although the association was not statistically significant (P =.077). We noted a significant association between thioredoxin-1 expression and patient survival (P =.004); higher score was associated with decreased survival. When adjusted for Dukes stage, thioredoxin-1 expression showed a statistically significant association with survival (P =.012). The work shows that increased thioredoxin-1 expression is a relatively late event in colorectal carcinogenesis and provides evidence in a small group of subjects with colorectal cancer of Dukes stages A through D that thioredoxin-1 expression may be an independent marker of patient prognosis.

Increased Expression and Secretion of Interleukin-6 in Patients with Barrett’s Esophagus

Purpose: Barrett’s esophagus (BE) is a common premalignant lesion of the distal part of the esophagus that arises as a consequence of chronic duodenogastroesophageal reflux. Interleukin (IL)-6 is a pleiotropic cytokine that regulates immune defense mechanisms and hematopoiesis. In addition, IL-6 may also be involved in malignant transformation and tumor progression. IL-6 has been shown to inhibit apoptosis. The major aim of this study was to evaluate expression of IL-6 in BE at the protein and mRNA levels. In addition, we tested whether proteins that are associated with IL-6 signaling, phosphorylated signal transducer and activator of transcription 3 and two antiapoptotic proteins, Bcl-xL and Mcl-1, are also expressed in the same tissues. Experimental Design: Biopsies of duodenum, BE, and squamous epithelium were evaluated by using a human cytokine protein array, ELISA, real-time PCR, and immunohistochemistry. Results: Increased IL-6 levels were found to be secreted from BE tissue compared with duodenum or squamous epithelium from sites adjacent or 5 cm away from the BE lesion. IL-6 mRNA was also elevated in BE compared with duodenum or squamous epithelium in five of seven patients. Immunohistochemical studies confirmed IL-6 expression in intestinal glandular epithelium in BE tissue. Activated signal transducer and activator of transcription 3, Mcl-1, and Bcl-xL are present at higher levels in BE glands, with lower levels being found in duodenum or squamous epithelium Conclusions: These data, taken together, suggest that elevated IL-6 levels in BE may contribute to the development of apoptosis resistance, thereby placing this epithelium at higher risk of developing malignancy.

Evaluation of cold knife urethrotomy for the treatment of anastomotic stricture after radical retropubic prostatectomy.

PURPOSE We evaluated the efficacy of cold knife urethrotomy for anastomotic stricture after radical retropubic prostatectomy. MATERIALS AND METHODS We contacted all patients who underwent cold knife urethrotomy for a symptomatic anastomotic stricture from May 1, 1992 through January 1, 2000 at our institution. A control group of patients who underwent radical retropubic prostatectomy but did not complain of a decreased urine stream was similarly evaluated. Maximum urinary flow rate, post-void residual urine volume, American Urological Association (AUA) symptom index for benign prostatic hyperplasia, and continence status with a questionnaire adapted from the RAND-University of California-Los Angeles Prostate Cancer Index were determined in each study participant. RESULTS We identified and contacted 61 patients. Complete data were collected on 36 of the 52 patients (59%) who agreed to participate. Mean time after urethrotomy was 31 months (range 1 to 77). In the control group the mean time after prostatectomy was 18.6 months (range 3 to 95). There was no statistically significant difference in the measured urinary parameters of maximum flow rate, post-void residual urine volume, AUA symptom index or continence status in the study and control groups. CONCLUSIONS Cold knife urethrotomy provides a safe and effective response for the initial treatment of patients with anastomotic stricture after radical retropubic prostatectomy. Maximum urinary flow, post-void residual volume, AUA symptom score and perceptions of continence are similar to those in patients who underwent radical retropubic prostatectomy and had no complaints of a weak urine stream.

Overexpression of Tumor Vascular Endothelial Growth Factor A May Portend an Increased Likelihood of Progression in a Phase II Trial of Bevacizumab and Erlotinib in Resistant Ovarian Cancer

Purpose: This phase II trial evaluated bevacizumab plus erlotinib in platinum-resistant ovarian cancer; exploratory biomarker analyses, including that of tumor vascular endothelial growth factor A (VEGF-A), were also done. Experimental Design: Forty heavily pretreated patients received erlotinib (150 mg/d orally) and bevacizumab (10 mg/kg i.v.) every 2 weeks until disease progression. Primary end points were objective response rate and response duration; secondary end points included progression-free survival (PFS), toxicity, and correlations between angiogenic protein levels, toxicity, and efficacy. Results: Grade 3 toxicities included skin rash (n = 6), diarrhea (n = 5), fatigue (n = 4), and hypertension (n = 3). Grade 4 toxicities were myocardial infarction (n = 1) and nasal septal perforation (n = 1). Only one grade 3 fistula and one grade 2 bowel perforation were observed. Nine (23.1%) of 39 evaluable patients had a response (median duration, 36.1+ weeks; one complete response), and 10 (25.6%) patients achieved stable disease, for a disease control rate of 49%. Median PFS was 4 months, and 6-month PFS was 30.8%. Biomarker analyses identified an association between tumor cell VEGF-A expression and progression (P = 0.03); for every 100-unit increase in the VEGF-A score, there was a 3.7-fold increase in the odds of progression (95% confidence interval, 1.1-16.6). Conclusions: Bevacizumab plus erlotinib in heavily pretreated ovarian cancer patients was clinically active and well tolerated. Erlotinib did not seem to contribute to efficacy. Our study raises the intriguing possibility that high levels of tumor cell VEGF-A, capable of both autocrine and paracrine interactions, are associated with resistance to bevacizumab, emphasizing the complexity of the tumor microenvironment. Clin Cancer Res; 16(21); 5320–8. ©2010 AACR.

Unique dietary‐related mouse model of colitis

Background: A high‐fat diet is a risk factor for the development of inflammatory bowel disease (IBD) in humans. Deoxycholate (DOC) is increased in the colonic contents in response to a high‐fat diet. Thus, an elevated level of DOC in the colonic lumen may play a role in the natural course of development of IBD. Methods: Wild‐type B6.129 mice were fed an AIN‐93G diet, either supplemented with 0.2% DOC or unsupplemented and sacrificed at 1 week, 1 month, 3 months, 4 months, and 8 months. Colon samples were assessed by histopathological, immunohistochemical, and cDNA microarray analyses. Results: Mice fed the DOC‐supplemented diet developed focal areas of colonic inflammation associated with increases in angiogenesis, nitrosative stress, DNA/RNA damage, and proliferation. Genes that play a central role in inflammation and angiogenesis and other related processes such as epithelial barrier function, oxidative stress, apoptosis, cell proliferation/cell cycle/DNA repair, membrane transport, and the ubiquitin‐proteasome pathway showed altered expression in the DOC‐fed mice compared with the control mice. Changes in expression of individual genes (increases or reductions) correlated over time. These changes were greatest 1 month after the start of DOC feeding. Conclusions: The results suggest that exposure of the colonic mucosa to DOC may be a key etiologic factor in IBD. The DOC‐fed mouse model may reflect the natural course of development of colitis/IBD in humans, and thus may be useful for determining new preventive strategies and lifestyle changes in affected individuals.

Combination Chemoprevention of Intestinal Carcinogenesis in a Murine Model of Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited syndrome in humans. The Apc Min/+ mouse, which expresses a mutant homolog of the adenomatous polyposis coli gene, is a model of FAP in humans. Treatment with the nonsteroidal anti-inflammatory drugs (NSAIDS) sulindac or celecoxib can suppress polyp development in FAP patients, but responses are generally transient and incomplete. Combination chemoprevention with the ornithine decarboxylase inhibitor difluoromethylornithine (DFMO) and either celecoxib or sulindac was evaluated in the Apc Min/+ mouse. Combinations of DFMO and either NSAID reduced intestinal tumor number by more than 80% (P < 0.0001) compared to untreated controls. In addition to the dramatic reduction in tumor number, the combination of DFMO and sulindac reduced the development of high-grade intestinal adenomas compared to sulindac alone (P = 0.003). The fraction of high-grade intestinal adenomas remaining after treatment was similar for the combination of DFMO and celecoxib and celecoxib alone. Only combinations of DFMO plus sulindac reduced total intestinal polyamine contents compared to untreated mice. These data support the rationale for treatment of FAP patients postcolectomy with DFMO combined with either celecoxib or sulindac but indicate that sulindac may be more effective than celecoxib in reducing intestinal polyamine contents and the incidence of high-grade intestinal adenomas when combined with DFMO.

The role of NO synthases in arginine-dependent small intestinal and colonic carcinogenesis

Arginine is catabolized by NOS2 and other nitric oxide synthases to form nitric oxide. We evaluated the roles of dietary arginine and Nos2 in Apc‐dependent intestinal tumorigenesis in Min mice with and without a functional Nos2 gene. NOS2 protein was expressed only in intestinal tissues of ApcMin/+ Nos2+/+ mice. NOS3 expression was higher in intestinal tissues of mice lacking Nos2, mainly in the small intestine. When diet was supplemented with arginine (0.2% and 2% in drinking water), lack of Nos2 results in decreased tumorigenesis in both small intestine and colon. In Nos2 knockout mice, supplemental arginine (up to 2%) caused a decrease in small intestinal tumor number and size. The arginine‐dependent decrease was associated with an increase in nitrotyrosine formation and apoptosis in the region of intestinal stem cells. Mice expressing Nos2 did not show these changes. These mice did, however, show an arginine‐dependent increase in colon tumor number and incidence, while no effect on apoptosis was seen. These changes were associated with increased nitrotyrosine formation in epithelial cells. Mice lacking Nos2 did not show changes in tumorigenesis or nitrotyrosine formation, while demonstrating an arginine‐dependent increase in apoptosis. These data suggest that Nos2 and dietary arginine have significant effects on intestinal and colonic tumorigenesis in Min mice. In both tissues, loss of Nos2 is associated with decreased tumorigenesis when mice are supplemented with dietary arginine. In the small intestine, Nos2 prevents the arginine‐induced decrease in tumor number and size, which is associated with NOS3 expression and increased apoptosis. In the colon, Nos2 is required for the arginine‐induced increase in tumor number and incidence.

Relationship between rate of change in acid exposure along the esophagus and length of Barrett's epithelium

OBJECTIVE:Gastroesophageal reflux disease (GERD) plays a major role in the development of Barretts esophagus. Recently, we demonstrated that duration of esophageal acid exposure in the distal esophagus correlates with the length of Barretts mucosa. The aim of this study was to determine whether there is a relationship between the rate of the change in acid exposure along the esophagus and the length of Barretts esophagus.METHODS:A total of 17 patients (16 men and one woman; mean age 66 ± 15 yr, range 41–83 yr) with varying lengths of biopsy-proven Barretts esophagus were recruited prospectively into the study. Ambulatory 24-h esophageal pH monitoring was performed using a commercially available pH probe with four sensors located 5 cm apart. For each patient, a least squares regression line of the fraction of the study that the pH was <4 against the height of the sensor above the lower esophageal sphincter was fit. The slope of the regression line was used to represent the rate of change in acid exposure. Linear regression analysis was conducted to analyze the relationship between the rate of change in acid exposure and the length of Barretts mucosa.RESULTS:The mean Barretts length was 5 ± 3 cm (range 1–11 cm). Linear regression demonstrated a statistically significant relationship between the rate of change in acid exposure and the length of Barretts esophagus for the 24-h duration of the study, as well as for the fraction of the study that patients were in the upright position (p = 0.0096 and 0.0076, respectively). For the supine position, the relationship did not reach statistical significance (p = 0.095).CONCLUSIONS:We demonstrated a significant relationship between the rate of change in acid exposure and the length of Barretts mucosa. Thus, as the rate at which recorded acid exposure values increases from the proximal to distal esophagus, the length of Barretts esophagus significantly increases (for percent total time and upright position).

Phase I Trial of Intraperitoneal Pemetrexed, Cisplatin, and Paclitaxel in Optimally Debulked Ovarian Cancer

Purpose: This phase I trial evaluated intraperitoneal (i.p.) pemetrexed, cisplatin, and paclitaxel in optimally debulked ovarian cancer. Experimental Design: Dose escalation of day 1 i.p. pemetrexed accrued three patients to each of five dose levels (60–1,000 mg/m2), along with day 2 i.p. cisplatin (75 mg/m2) and day 8 i.p. paclitaxel (60 mg/m2). The goals were to determine maximum tolerated dose (MTD), 18-month progression-free survival (PFS), and pharmacokinetics of i.p. pemetrexed. Results: Cycles, given every 21 days, had an 80% 6-cycle completion rate. There was minimal grade III toxicity in the first 4 dose levels and remarkably an almost complete absence of peripheral neuropathy and alopecia. At the highest dose level, two of three patients experienced ≥grade III and dose-limiting toxicity (DLT; hematologic, infection, gastrointestinal). There was a pharmacokinetic advantage for i.p. pemetrexed with an intraperitoneal:plasma area under the concentration–time curve ratio of 13-fold. Neither analysis of pharmacokinetic nor homocysteine levels explains the unexpected severity of toxicity in those two patients. On the basis of plasma C24h levels, the 42 cycles at ≥500 mg/m2 i.p. pemetrexed without DLT, the MTD appears to be 500 mg/m2. Median PFS is 30.1 months; 18-month PFS is 78.6% (median follow-up 22.4 months). Conclusions: This i.p.-only regimen in front-line ovarian cancer is feasible with PFS in line with recent literature. We suggest phase II trials of this regimen in this population with i.p. pemetrexed at 500 mg/m2. The favorable toxicity profile at doses <1,000 mg/m2, which needs to be confirmed, appears to compare well with standard combination i.v./i.p. platinum/taxane chemotherapy in this disease. Clin Cancer Res; 18(9); 2668–78. ©2012 AACR.

The effects of dietary selenomethionine on polyamines and azoxymethane-induced aberrant crypts

We evaluated the effects of dietary selenomethionine supplementation on colonic polyamine levels and the ability of L-selenomethionine supplementation to modulate the carcinogenic activity of azoxymethane (AOM) in the rat colon. Four-week-old male F344 rats were treated with 15 mg/kg body weight of AOM once a week for 2 weeks. Dietary selenomethionine at a concentration of either 1 or 2 ppm was administered in AIN-76A rodent diet to AOM-treated animals for 16 weeks. Aberrant crypt foci (ACF), precursor lesions of colon cancer, were investigated after the 16 week treatment course. Selenomethionine given in the diet at 2 ppm markedly reduced the number of aberrant crypt foci. The multiplicity of ACFs (i.e. the number of aberrant crypts/focus) and the percentage of microadenomas were also affected by selenomethionine in a dose dependent manner. However, evaluation of the colonic tissue polyamine levels between control and treated groups showed no significant difference. These results demonstrate that selenomethionine can modulate the development of AOM-induced premalignant lesions through a polyamine-independent mechanism.