Faculty Publications

BACKGROUND: The scientific potential of animal models of carcinogenesis has not been fully realized because of our limited ability to monitor tumor growth in vivo. OBJECTIVE: To develop an endoscopy-based protocol for the accurate estimation of adenoma size in vivo from images obtained during colonoscopy. DESIGN: To compare estimates of lesion size acquired during endoscopy with those obtained from magnetic resonance imaging (MRI) and at necropsy. SETTING: A small-animal imaging facility. SUBJECTS: Adenomatous polyposis coli multiple intestinal metaplasia Fox Chase Cancer Center mice that develop multiple colorectal adenomas. METHODS: The mice received colonoscopic examination by using a rigid endoscope, and high-resolution images of colon adenomas were captured by using a charge-coupled-device camera. Lesion size was estimated by comparing the dimensions of the adenoma relative to a reference rod by using a novel geometric construction. The resulting areas were compared with estimates from MRIs and validated at necropsy. MAIN OUTCOME MEASUREMENTS: Cross-sectional area of colon adenomas. RESULTS: The cross-sectional area of 20 adenomas was measured in vivo during colonoscopy and compared with the size as measured at necropsy, which yielded a Pearson correlation coefficient of 0.94 (P = 6.52 x 10(-9)). Assessment of interoperator variability, when using measurements from 11 adenomas, yielded a Pearson correlation coefficient of 0.85 (P = 4.35 x 10(-3)) and demonstrated excellent reproducibility. LIMITATIONS: Only the distal colon could be viewed, and endoscopic measurements were 2-dimensional. CONCLUSIONS: An endoscopic method for the reliable measurement of colorectal adenomas in vivo was established. The application of this technique to mouse models of colon carcinogenesis will provide unique insight into the dynamics of adenoma growth.

This article presents methods for testing covariate effect in the Cox proportional hazards model based on Kullback-Leibler divergence and Renyi's information measure. Renyi's measure is referred to as the information divergence of order gamma (gamma not equal 1) between two distributions. In the limiting case gamma -> 1, Renyi's measure becomes Kullback-Leibler divergence. In our case, the distributions correspond to the baseline and one possibly due to a covariate effect. Our proposed statistics are simple transformations of the parameter vector in the Cox proportional hazards model, and are compared with the Wald, likelihood ratio and score tests that are widely used in practice. Finally, the methods are illustrated using two real-life data sets.

Background: The impact of the antiinflammatory agent 5-aminosalicylic acid (5-ASA) on the risk for colitis-associated colorectal cancer remains controversial. The chemopreventive activity of 5-ASA was evaluated in the Swiss Webster model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated neoplasia. Methods: Mice were injected with AOM (7.4 mg/kg i.p.) and randomized to receive either vehicle or 5-ASA (75, 150, and 225 mg/kg) for the remainder of the study. DSS treatment began at 9 weeks of age and continued for 3 cycles. At the time of sacrifice (18 weeks of age), the entire colon and rectum were processed for histopathologic examination. Results: An inverse trend was observed between dose and Multiplicity of colonic dysplasias in all drug-treated groups (P = 0.03), with animals receiving 75 mg/kg 5-ASA exhibiting 56% of the number of dysplasias of the AOM/DSS controls (mean +/- SEM: 7.6 +/- 1.4 and 13.6 +/- 2.7. respectively). Administration of 75 mg/kg 5-ASA decreased both the mean multiplicity of flat dysplasias (1.8 +/- 0.4 for drug-treated versus 5.6 +/- 1.2 for AOM/DSS control) and the burden of polypoid dysplasias (tumor burden: 6.7 +/- 2.7 for drug-treated versus 14.9 +/- 3.9 units for AOM/DSS controls) significantly (P = 0.002 and 0.04. respectively). Inflammation was least severe in the 75 mg/kg group. which exhibited the fewest number of colorectal tumors. Conclusions: These data suggest that low-dose 5-ASA may be efficacious in preventing colitis-associated dysplasias and provide strong support for optimizing this therapy for the prevention of colonic neoplasms in patients with ulcerative colitis. (Inflamm Bowel Dis 2008; 14:1341-1347)

Background: Studies show that holding single antithrombotic agents perioperatively increases the risk of acute thrombotic events and does not significantly decrease the risk of bleeding complications in dermatological surgery. Recent data suggest that selected patients may benefit from combination therapy in preventing acute thrombotic events. Objective: We sought to evaluate postoperative bleeding complications in patients who underwent Mohs micrographic surgery while using multiple agents perioperatively compared with patients using a single agent or none at all. Methods: We conducted a retrospective chart review of patients treated in one academic Mohs micrographic surgery department during 1 year. Results: Patients taking two or more agents at the time of surgery were more likely to bleed than those taking one agent or none at all (P = .0016, Fisher's exact). Limitations: Small sample size and retrospective nature were limitations. Conclusion: Perioperative use of more than one antithrombotic agent increases postoperative bleeding risk.

BACKGROUND: The impact of the antiinflammatory agent 5-aminosalicylic acid (5-ASA) on the risk for colitis-associated colorectal cancer remains controversial. The chemopreventive activity of 5-ASA was evaluated in the Swiss Webster model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated neoplasia. METHODS: Mice were injected with AOM (7.4 mg/kg i.p.) and randomized to receive either vehicle or 5-ASA (75, 150, and 225 mg/kg) for the remainder of the study. DSS treatment began at 9 weeks of age and continued for 3 cycles. At the time of sacrifice (18 weeks of age), the entire colon and rectum were processed for histopathologic examination. RESULTS: An inverse trend was observed between dose and multiplicity of colonic dysplasias in all drug-treated groups (P = 0.03), with animals receiving 75 mg/kg 5-ASA exhibiting 56% of the number of dysplasias of the AOM/DSS controls (mean +/- SEM: 7.6 +/- 1.4 and 13.6 +/- 2.7, respectively). Administration of 75 mg/kg 5-ASA decreased both the mean multiplicity of flat dysplasias (1.8 +/- 0.4 for drug-treated versus 5.6 +/- 1.2 for AOM/DSS control) and the burden of polypoid dysplasias (tumor burden: 6.7 +/- 2.7 for drug-treated versus 14.9 +/- 3.9 units for AOM/DSS controls) significantly (P = 0.002 and 0.04, respectively). Inflammation was least severe in the 75 mg/kg group, which exhibited the fewest number of colorectal tumors. CONCLUSIONS: These data suggest that low-dose 5-ASA may be efficacious in preventing colitis-associated dysplasias and provide strong support for optimizing this therapy for the prevention of colonic neoplasms in patients with ulcerative colitis.

The p21-activated kinases (Paks) serve as effectors of the Rho family GTPases Rac and Cdc42. The six human Paks are divided into two groups based on sequence similarity. Group I Paks (Pak1 to -3) phosphorylate a number of substrates linking this group to regulation of the cytoskeleton and both proliferative and anti-apoptotic signaling. Group II Paks (Pak4 to -6) are thought to play distinct functional roles, yet their few known substrates are also targeted by Group I Paks. To determine if the two groups recognize distinct target sequences, we used a degenerate peptide library method to comprehensively characterize the consensus phosphorylation motifs of Group I and II Paks. We find that Pak1 and Pak2 exhibit virtually identical substrate specificity that is distinct from that of Pak4. Based on structural comparisons and mutagenesis, we identified two key amino acid residues that mediate the distinct specificities of Group I and II Paks and suggest a structural basis for these differences. These results implicate, for the first time, residues from the small lobe of a kinase in substrate selectivity. Finally, we utilized the Pak1 consensus motif to predict a novel Pak1 phosphorylation site in Pix (Pak-interactive exchange factor) and demonstrate that Pak1 phosphorylates this site both in vitro and in cultured cells. Collectively, these results elucidate the specificity of Pak kinases and illustrate a general method for the identification of novel sites phosphorylated by Paks.

This study examined the efficacy of a couple-focused group intervention on psychological adaptation of women with early stage breast cancer and evaluated whether perceived partner unsupportive behavior or patient functional impairment moderated intervention effects. Two hundred thirty-eight women were randomly assigned to receive either 6 sessions of a couple-focused group intervention or usual care. Intent-to-treat growth curve analyses indicated that participants assigned to the couples' group reported lower depressive symptoms. Women rating their partners as more unsupportive benefited more from the intervention than did women with less unsupportive partners, and women with more physical impairment benefited more from the intervention group than did women with less impairment. Subgroup analyses comparing women attending the couple-focused group intervention with women not attending groups and with usual care participants indicated that women attending sessions reported significantly less distress than did women receiving usual care and women who dropped out of the intervention. ((c) 2005 APA, all rights reserved). PURPOSE: To compare several characteristics of alternative definitions of biochemical failure (BF) in men with extended follow-up after radiotherapy (RT) with or with androgen deprivation therapy (ADT) for prostate cancer. METHODS AND MATERIALS: From December 1, 1991, to April 30, 1998, 688 men with Stage T1c-T3NX-N0M0 prostate cancer received RT alone (n = 586) or RT plus ADT (n = 102) with a minimal follow-up of 4 years and five or more "ADT-free" posttreatment prostate-specific antigen levels. BF was defined by three methods: (1) the ASTRO definition (three consecutive rises in prostate-specific antigen level); (2) a modified American Society for Therapeutic Radiology Oncology (ASTRO) definition requiring two additional consecutive rises when a decline immediately subsequent to three consecutive rises occurred; and (3) the "Houston" or nadir plus 2-ng/mL definition (a rise of at least 2 ng/mL greater than the nadir). The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were determined for each using clinical progression as the endpoint. Furthermore, the misclassification rates for a steadily rising prostate-specific antigen level, ability to satisfy the proportional hazards (RT with or without ADT), effects of short follow-up, and intervals to the diagnosis of BF were compared. RESULTS: The misclassification rate for BF using the nadir plus 2-ng/mL definition was 2% for RT alone and 0% for RT plus ADT compared with 0% and 0% for the modified ASTRO definition, and 5% and 23% for the ASTRO definition, respectively. The hazard rates for RT alone and RT plus ADT were proportional only for the nadir plus 2 ng/mL definition and seemingly unaffected by the length of follow-up. For RT with or without ADT, the nadir plus 2 ng/mL definition was the most specific (RT, 80% vs. RT plus ADT, 75%) with the greatest positive predictive value (RT, 36% vs. RT plus ADT, 25%) and overall accuracy (RT, 81% vs. RT plus ADT, 77%). A greater proportion of BF was diagnosed in the first 2 years of follow-up with the nadir plus 2 ng/mL definition compared with the ASTRO definition (13% vs. 5%, p = 0.0138, chi-square test). CONCLUSION: The nadir plus 2 ng/mL definition was the best predictor of sustained, true, biochemical, and clinical failure, and was not affected by the use of ADT or follow-up length. Clinical experience has resulted in the identification of a relatively small number of absolute contraindications to breast-conserving therapy (BCT). These contraindications are readily identified by a clinical evaluation and diagnostic mammography. Local failure rates of less than 10% at 10 years support the idea that patients can be reliably selected for BCT with standard clinical modalities. The availability of magnetic resonance (MR) imaging has raised questions about its role in patient selection for BCT. MR imaging identifies additional cancer in 10-54% of patients with apparently localized disease, resulting in mastectomies that would not otherwise have been done. Clinical experience suggests that the majority of this disease is controlled by radiotherapy. Studies demonstrating clinical benefit in terms of decreased rates of local recurrence or fewer surgeries are needed before MR is used for routine selection of patients for BCT. It is well known that the biological and carcinogenic effects of 17beta-estradiol (E(2)) are mediated via nuclear estrogen receptors (ERs) by regulating nuclear gene expression. Several rapid, non-nuclear genomic effects of E(2) are mediated via plasma membrane-bound ERs. In addition, there is accumulating evidence suggesting that mitochondria are also important targets for the action of estrogens and ERs. This review summarized the studies on the effects of estrogens via ERs on mitochondrial structure and function. The potential physiological and pathophysiological implications of deficiency and/or overabundance of these E(2)/ER-mediated mitochondrial effects in stimulation of cell proliferation, inhibition of apoptosis, E(2)-mediated cardiovascular and neuroprotective effects in target cells are also discussed. Proprotein convertases (PCs) are a group of Ca(2+)-dependent serine proteases that have homology to the endoproteases subtilisin (bacteria) and kexin (yeast). This group is comprised of less than a dozen members, known as furin/PACE, PC1/PC3, PC2, PC4, PACE4, PC5/PC6, PC7/PC8/LPC, SKI/S1P, and NARC-1/PCSK9. Four PCs (Furin, PACE4, PC5, and PC7) have been localized to several different tissues and epithelial or nervous system tumors. PCs activate their cognate substrates by limited proteolysis at the consensus sequence RXR/KR downward arrow. Many PC substrates are well known cancer-associated proteins such as growth factors, growth factor receptors, integrins, and matrix metalloproteases (MMPs). For example, IGF-1 and its receptor, TGF-beta, VEGF-C, and MT-MMPs have direct roles in tumor progression and metastasis. Furin, a well-studied member of the PC family, has been associated with enhanced invasion and proliferation in head and neck, breast, and lung cancer. Conversely, inhibition of PC activity by PDX or several PC pro-segments, resulted in reduced processing of these key cancer-related substrates in human squamous cell carcinomas (SCC), colon adenocarcinoma, and astrocytoma cell lines. In parallel to these changes in cell proliferation and invasiveness as well as metastatic ability were markedly impaired. By controlling the maturation/activation of key cancer-associated proteins, PCs act as "master switches" at different levels during tumor development and progression. The manifold effects of PCs, influencing tumor cell proliferation, motility, adhesiveness, and invasiveness, should be exploited by further developing competitive/inhibitory therapeutic strategies that would be able to neutralize simultaneously the most salient cancer cell properties. (c) 2005 Wiley-Liss, Inc. Squamous cell cancer of the head and neck is a debilitating disease. Combined modality treatments with surgery, chemotherapy, and radiation have been evaluated in multiple settings over the past 30 years. While surgery and radiation remain the potentially curative modalities, the addition of chemotherapy can in some cases decrease the rate of distant metastasis. When concurrent chemoradiation is employed, overall survival is improved, although toxicity can be higher. Studies have also shown a role for concurrent treatment in an effort to avoid total laryngectomy and preserve organ function. Multidisciplinary evaluation should be a routine part of care in this patient population. Future areas of research include the epidermal growth factor inhibitors, which have shown promise in early studies. Malignant mesothelioma has been linked to asbestos exposure and generally has a poor prognosis because it is often diagnosed in advanced stages and is refractory to conventional therapy. Human malignant mesotheliomas accumulate multiple somatic genetic alterations, including inactivation of the NF2 and CDKN2A/ARF tumor suppressor genes. To better understand the significance of NF2 inactivation in malignant mesothelioma and identify tumor suppressor gene alterations that cooperate with NF2 loss of function in malignant mesothelioma pathogenesis, we treated Nf2 (+/-) knockout mice with asbestos to induce malignant mesotheliomas. Asbestos-exposed Nf2 (+/-) mice exhibited markedly accelerated malignant mesothelioma tumor formation compared with asbestos-treated wild-type (WT) littermates. Loss of the WT Nf2 allele, leading to biallelic inactivation, was observed in all nine asbestos-induced malignant mesotheliomas from Nf2 (+/-) mice and in 50% of malignant mesotheliomas from asbestos-exposed WT mice. For a detailed comparison with the murine model, DNA analyses were also done on a series of human malignant mesothelioma samples. Remarkably, similar to human malignant mesotheliomas, tumors from Nf2 (+/-) mice showed frequent homologous deletions of the Cdkn2a/Arf locus and adjacent Cdkn2b tumor suppressor gene, as well as reciprocal inactivation of Tp53 in a subset of tumors that retained the Arf locus. As in the human disease counterpart, malignant mesotheliomas from the Nf2 (+/-) mice also showed frequent activation of Akt kinase, which plays a central role in tumorigenesis and therapeutic resistance. Thus, this murine model of environmental carcinogenesis faithfully recapitulates many of the molecular features of human malignant mesothelioma and has significant implications for the further characterization of malignant mesothelioma pathogenesis and preclinical testing of novel therapeutic modalities. Brain metastases are an important sequelae of many types of cancer, most commonly lung cancer. Current treatment options include whole-brain radiation therapy (WBRT), surgical resection, stereotactic radiosurgery, and chemotherapy. Corticosteroids and antiepileptic medications are commonly used for palliation of mass effect and seizures, respectively. The overall median survival is only 4 months after WBRT. Combined-modality strategies of WBRT with either chemotherapy or novel anticancer agents are under clinical investigation. Promising results have been obtained with several experimental agents and confirmatory phase III trials are underway. Although improvement in overall survival has not been seen universally, reduction in death due to progression of brain metastases and prolongation of the time to neurologic and neurocognitive progression have been reported in selected series. On the basis of these findings, it might be possible to identify new agents that may enhance the efficacy of WBRT. PURPOSE: Laparoscopic renal and adrenal surgery is an accepted standard of care. This can be accomplished by a transperitoneal or retroperitoneal approach. In patients with extensive prior intra-abdominal surgery with or without radiation the retroperitoneal laparoscopic approach may avoid bowel adhesions and potential operative complications. We compared clinical outcomes of the laparoscopic retroperitoneal approach in patients with prior open abdominal surgery with or without radiation to outcomes in those with no surgical history. MATERIALS AND METHODS: We evaluated clinical and functional parameters in 78 consecutive patients undergoing retroperitoneoscopic renal or adrenal surgery performed by a single surgeon in a 36-month period, including radical nephrectomy with or without ureterectomy in 50, nerve sparing surgery in 8, ablation in 16 and adrenalectomy in 4. All transperitoneal procedures during the same period were excluded from analysis. Patients were divided into 48 who underwent prior abdominal surgery with or without radiation (group 1) and 30 who did not (group 2). Prior abdominal surgeries in group 1 patients were open and they were major in 42 and/or minor in 39. An additional 6 patients in group 1 received prior abdominal radiation overlapping the planned surgical field. RESULTS: No statistically significant differences were noted between the groups in any parameter assessed, including operative time, blood loss, time to first oral intake, hospital stay or the complication rate (p >0.05). There were no enterotomies in either group. There were no open conversions in group 1, while there were 2 in group 2 (renal vein injury and splenorrhaphy secondary to lymphoma, respectively). Pathological findings showed malignancy in 57 cases (renal cell carcinoma, transitional cell carcinoma, carcinoid disease and metastases) and benign disease in 21 (oncocytoma, adenoma, pyelonephritis and complex cysts). All margins were negative except in 1 group patient with carcinoma in situ at the bladder cuff margin. CONCLUSIONS: The retroperitoneoscopic approach to the kidney and adrenal glands can be used in patients with extensive prior open abdominal surgery and/or radiation without significant increases in morbidity or convalescence. SUMMARY: Molecular Integrated Development Environment (MolIDE) is an integrated application designed to provide homology modeling tools and protocols under a uniform, user-friendly graphical interface. Its main purpose is to combine the most frequent modeling steps in a semi-automatic, interactive way, guiding the user from the target protein sequence to the final three-dimensional protein structure. The typical basic homology modeling process is composed of building sequence profiles of the target sequence family, secondary structure prediction, sequence alignment with PDB structures, assisted alignment editing, side-chain prediction and loop building. All of these steps are available through a graphical user interface. MolIDE's user-friendly and streamlined interactive modeling protocol allows the user to focus on the important modeling questions, hiding from the user the raw data generation and conversion steps. MolIDE was designed from the ground up as an open-source, cross-platform, extensible framework. This allows developers to integrate additional third-party programs to MolIDE. AVAILABILITY: http://dunbrack.fccc.edu/molide/molide.php CONTACT: rl_dunbrack@fccc.edu. Two-hybrid screening is a standard method used to identify and characterize protein-protein interactions and has become an integral component of many proteomic investigations. The two-hybrid system was initially developed using yeast as a host organism. However, bacterial two-hybrid systems have also become common laboratory tools and are preferred in some circumstances, although yeast and bacterial two-hybrid systems have never been directly compared. We describe here the development of a unified yeast and bacterial two-hybrid system in which a single bait expression plasmid is used in both organismal milieus. We use a series of leucine zipper fusion proteins of known affinities to compare interaction detection using both systems. Although both two-hybrid systems detected interactions within a comparable range of interaction affinities, each demonstrated unique advantages. The yeast system produced quantitative readout over a greater dynamic range than that observed with bacteria. However, the phenomenon of "autoactivation" by baits was less of a problem in the bacterial system than in the yeast. Both systems identified physiological interactors for a library screen with a cI-Ras test bait; however, non-identical interactors were obtained in yeast and bacterial screens. The ability to rapidly shift between yeast and bacterial systems provided by these new reagents should provide a marked advantage for two-hybrid investigations. In addition, the modified expression vectors we describe in this report should be useful for any application requiring facile expression of a protein of interest in both yeast and bacteria. Defining Biochemical Failure after Radiotherapy with and without Androgen Deprivation for Prostate Cancer Limiting breast surgery to the proper minimum Regulation of mitochondrial respiratory chain structure and function by estrogens/estrogen receptors and potential physiological/pathophysiological implications Proprotein convertases: "Master switches" in the regulation of tumor growth and progression Combined modality treatment of squamous cell cancer of the head and neck A mouse model recapitulating molecular features of human mesothelioma Regulation of cell death in oncogenesis Current management of brain metastases, with a focus on systemic options Prior abdominal surgery and radiation do not complicate the retroperitoneoscopic approach to the kidney or adrenal gland MollDE: a homology modeling framework you can click with A combined yeast/bacteria two-hybrid system: development and evaluation