Faculty Publications

Intracellular organic osmolytes are present in certain organisms adapted to harsh environments. These osmolytes protect intracellular macromolecules against denaturing environmental stress. In contrast to the usually benign effects of most organic osmolytes, the waste product urea is a well-known perturbant of macromolecules. Although urea is a perturbing solute which inhibits enzyme activity and stability, it is employed by some species as a major osmolyte. The answer to this paradox was believed to be the discovery of protective osmolytes (methylamines). We review the current state of knowledge on the various ways of counteracting the harmful effects of urea in nature and the mechanisms for this. This review ends with the mechanistic idea that cellular salt (KCl/NaCl) plays a crucial role in counteracting the effects of urea, either by inducing required chaperones or methylamines, or by thermodynamic interactions with ureadestabilised proteins. We also propose future opportunities and challenges in the field.

BACKGROUND: The aim of the study was to determine whether tumor-infiltrating lymphocytes and/or tumor mitotic activity could identify subgroups of patients with advanced serous epithelial ovarian cancer who would maximally benefit from aggressive surgical cytoreduction. METHODS: Snap-frozen specimens from 134 consecutive patients with stage III or IV serous or poorly differentiated ovarian adenocarcinoma undergoing primary debulking surgery from a single US institution were characterized based on CD3(+), CD8(+), FoxP3(+) tumor-infiltrating lymphocytes, and Ki67 expression. Kaplan-Meier survival curves were estimated and compared using a log-rank statistic. A multivariate Cox model was used to estimate adjusted hazard ratios. Interactions were modeled using recursive partitioning based on maximal prognostic differentiation. RESULTS: Brisk intraepithelial CD8+ cells (P = .035) and low Ki67 expression (P = .042) portended prolonged survival. The T-cell infiltration was more likely to occur in tumors with high proliferation index. Patients whose tumors exhibited low Ki67 expression and high intraepithelial CD8+ frequency had a 5-year survival rate of 73.3%. Patients with aggressive tumor behavior, that is, whose tumors exhibited low frequency of intraepithelial CD8+ T cells or high Ki67 expression were more likely to draw benefit from aggressive surgical cytoreduction. Survival was similar for patients with brisk CD8+ T cells who had optimal or suboptimal debulking. Likewise, survival was similar for patients with low Ki67 expression who had optimal or suboptimal debulking. CONCLUSIONS: For the first time, these novel interactions of T cells, tumor proliferation index, and surgical treatment reveal that biological prognosticators may be useful for surgical decision making in ovarian cancer. Cancer 2009;115:2891-902. (C) 2009 American Cancer Society.

Purpose: We determined whether a relationship exists between primary tumor size and histopathological features in cases of localized renal cancer. Materials and Methods: SEER data were used to create a cohort of patients who were diagnosed with localized node negative renal masses from 1988 to 2004. Nuclear grade was divided into low and high grade groups. We used a multinomial logistic model to predict the probability of nuclear grade and histological subtype with increasing primary tumor size. Results: SEER data showed that 19,932 patients with localized renal masses were evaluated. The overall nuclear grade distribution was 80% and 20% for low and high grade tumors, respectively. A multinomial logistic model revealed that the probability of a high grade tumor increased with size. For each I cm increase in size of a primary localized renal cell carcinoma the odds of high grade disease increased by 13% (OR 1.13, p <0.001). Multinomial models also predicted that the odds of papillary vs clear cell renal cell carcinoma decreased with tumor size. Conversely the odds of chromophobe vs clear cell renal cell carcinoma increased with increasing tumor size. Conclusions: Most localized node negative renal cell carcinomas are low grade. Although the probability of a high grade tumor increases with size, almost 85% of renal cell carcinomas smaller than 4 cm and 70% of localized renal cell carcinomas larger than 7 cm demonstrate low nuclear grade. The probability of detecting particular histological subtypes also varies with increasing tumor size. These data suggest that many localized renal tumors can grow large locally without acquiring metastatic potential.

Having substantial missing data is a common problem in administrative and cancer registry data. We propose a sensitivity analysis to evaluate the impact of a covariate that is potentially missing not at random in survival analyses using Weibull proportional hazards regressions. We apply the method to an investigation of the impact of missing grade on post-surgical mortality outcomes in individuals with metastatic kidney cancer. Data came from the Surveillance Epidemiology and End Results (SEER) registry which provides population-based information on those undergoing cytoreductive nephrectomy. Tumor grade is an important component of risk stratification for patients with both localized and metastatic kidney cancer. Many individuals in SEER with metastatic kidney cancer are missing tumor grade information. We found that surgery was protective, but that the magnitude of the effect depended on assumptions about the relationship of grade with missingness. Copyright (c) 2009 John Wiley &amp; Sons, Ltd.

Merlin loss causes benign tumours of the nervous system, mainly schwannomas and meningiomas. Schwannomas show enhanced Rac1 and Cdc42 activity, the p21-activated kinase 2 (PAK2) activation and increased ruffling and cell adhesion. PAK regulates activation of merlin. PAK has been proposed as a potential therapeutic target in schwannomas. However where PAK stands in the Rac pathway is insufficiently characterised. We used a novel small-molecule PAK inhibitor, IPA-3, to investigate the role of PAK activation on Rac1/Cdc42 activity, cell spreading and adhesion in human primary schwannoma and Schwann cells. We show that IPA-3 blocks activation of PAK2 at Ser192/197 that antagonises PAK's interaction with Pix. Accordingly, Pix-mediated Rac1 activation is decreased in IPA-3 treated schwannoma cells, indicating that PAK acts upstream of Rac. We show that this Rac activation at the level of focal adhesions in schwannoma cells is essential for cell spreading and adhesion in Schwann and schwannoma cells. (C) 2009 Elsevier Inc. All rights reserved.

T-cell lymphomas (TCLs) classically have a poorer response to therapy when compared with B-cell lymphomas and account for only 10-15% of all lymphoid malignancies. Hepatosplenic TCLs are a rare subset of this group that usually present with hepatosplenomegaly, B-symptoms, and only rarely with lymphadenopathy. This disease process, also known as gamma/delta (gamma/delta) TCL because of the expression of the T-cell receptor gamma/delta chain, tends to present in young male patients. Hepatosplenic TCLs have recently gained notoriety because of the realization that patients with long-term treatment of some immunomodulators can develop this potentially fatal disease. These facts are exacerbated by the fact that patients with this disease rarely enjoy remissions of more than brief duration with common chemotherapeutic agents or bone marrow transplants. A novel agent, pralatrexate, has recently been found to have a dramatic activity in this patient population with refractory/relapsed disease. Unfortunately, patients with hepatosplenic TCL often present with thrombocytopenia and this new agent is contraindicated in these patients because of the potential exacerbation of thrombocytopenia with this agent. Because of this we attempted a laparoscopic-assisted splenectomy in one patient with grade 4 thrombocytopenia. Postoperatively the patient's thrombocytopenia resolved, permitting him to begin treatment with this potentially life-saving agent. Due to the lethality of this disease and potential efficacy of new therapies, we believe splenectomy should be considered in patients with hepatosplenic lymphoma in an effort to improve the treatment options and survival of patients with this challenging disease.

Many human diseases are caused by missense substitutions that result in misfolded proteins that lack biological function. Here we express a mutant form of the human cystathionine beta-synthase protein, I278T, in Saccharomyces cerevisiae and show that it is possible to dramatically restore protein stability and enzymatic function by manipulation of the cellular chaperone environment. We demonstrate that Hsp70 and Hsp26 bind specifically to I278T but that these chaperones have opposite biological effects. Ethanol treatment induces Hsp70 and causes increased activity and steady-state levels of I278T. Deletion of the SSA2 gene, which encodes a cytoplasmic isoform of Hsp70, eliminates the ability of ethanol to restore function, indicating that Hsp70 plays a positive role in proper I278T folding. In contrast, deletion of HSP26 results in increased I278T protein and activity, whereas overexpression of Hsp26 results in reduced I278T protein. The Hsp26-I278T complex is degraded via a ubiquitin/proteosome-dependent mechanism. Based on these results we propose a novel model in which the ratio of Hsp70 and Hsp26 determines whether misfolded proteins will either be refolded or degraded.

Purpose: To report a case of a choroidal melanoma that presented with painful scleritis and choroidal effusion. Methods: Interventional case report with cytopathologic correlation. Results: A 78-year-old otherwise healthy woman presented with sudden, severe painful ocular inflammation and marked injection of the right eye over a 3-day period, consistent with scleritis. Upon referral, 360 degrees of scleral and Conjunctival injection and peripheral choroidal effusion were found. In addition, a solid hemorrhagic, choroidal mass was evident, Suspicious for Melanoma. Fine needle aspiration biopsy of the choroidal mass confirmed necrotic melanoma. The melanoma was treated with iodine 125 plaque radiotherapy, and during surgery, the temporal sclera was markedly edematous and the orbital tissue was fibrotic, presumed related to inflammation. Two months after radiotherapy, the scleritis and choroidal effusion had resolved. Conclusion: Uveal effusion can rarely occur With uveal melanoma. particularly when the tumor is necrotic.

Purpose: To examine the influence of selected demographic and clinical variables on the intensity of symptoms in two previously identified symptom clusters (psychoneurological and upper gastrointestinal) across the treatment trajectory for breast cancer. Design: A secondary analysis was conducted with a sample of 282 female breast-cancer patients who were receiving chemotherapy or radiation therapy in two American cancer centers. Data were collected three times across the treatment trajectory: baseline (before chemotherapy or radiation treatment) and two follow-up times after treatment initiation. Method: Multiple regression analyses were done at each time point to examine the influence of selected demographic and clinical variables on the intensity of symptoms in each cluster. Findings: Baseline physical performance status was a consistent predictor of symptom intensity in the psychoneurological cluster across time whereas age and treatment modality were consistent predictors of symptom intensity in the upper gastrointestinal cluster. Poor physical performance at baseline predicted more intense psychoneurological symptoms. Younger women and women undergoing chemotherapy experienced more intense gastrointestinal symptoms. In addition, at the second follow-up treatment modality also influenced intensity of symptoms in the psychoneurological cluster and race and baseline physical performance status also influenced the intensity of symptoms in the upper gastrointestinal cluster. Conclusions: Clinicians can anticipate that younger patients, patients with poor baseline physical performance status, and patients who receive chemotherapy will have more intense treatment-related gastrointestinal and psychoneurological symptoms during adjuvant breast cancer therapy. Further research is needed to determine whether collective management for symptoms in a cluster may be beneficial. Clinical Relevance: Clinicians can use findings from the present study to identify patients who need greater attention to symptom assessment and management, including anticipatory counseling of patients and families.

A core set of oncoproteins is overexpressed or functionally activated in many types of cancer, and members of this group have attracted significant interest as subjects for development of targeted therapeutics. For some oncoproteins such as EGFR/ErbB1, both small molecule and antibody agents have been developed and applied in the clinic for over a decade. Analysis of clinical outcomes has revealed an initially unexpected complexity in the response of patients to these agents. Diverse factors, including developmental lineage of the tumor progenitor cell, co-mutation or epigenetic modulation of genes encoding proteins in an extended EGFR signaling network or regulating core survival responses in individual tumors, and environmental factors including inflammatory agents and viral infection, all have been identified as modulating response to treatment with EGFR-targeted drugs. Second and third generation therapeutic strategies increasingly incorporate knowledge of cancer type-specific signaling environments, in a more personalized treatment approach. This review takes squamous cell carcinoma of the head and neck (SCCHN) as a specific example of an EGFR-involved cancer with idiosyncratic biological features that influence design of treatment modalities, with particular emphasis on commonalities and differences with other cancer types. (C) 2009 Elsevier Inc. All rights reserved.

Studies of the formation of pancreas and liver progenitors have focused on individual inductive signals and cellular responses. Here, we investigated how bone morphogenetic protein, transforming growth factor-beta (TGFbeta), and fibroblast growth factor signaling pathways converge on the earliest genes that elicit pancreas and liver induction in mouse embryos. The inductive network was found to be dynamic; it changed within hours. Different signals functioned in parallel to induce different early genes, and two permutations of signals induced liver progenitor domains, which revealed flexibility in cell programming. Also, the specification of pancreas and liver progenitors was restricted by the TGFbeta pathway. These findings may enhance progenitor cell specification from stem cells for biomedical purposes and can help explain incomplete programming in stem cell differentiation protocols.