Eugene Lee

KU675, a Concomitant Heat-Shock Protein Inhibitor of Hsp90 and Hsc70 that Manifests Isoform Selectivity for Hsp90α in Prostate Cancer Cells

The 90-kDa heat-shock protein (Hsp90) assists in the proper folding of numerous mutated or overexpressed signal transduction proteins that are involved in cancer. Inhibiting Hsp90 consequently is an attractive strategy for cancer therapy as the concomitant degradation of multiple oncoproteins may lead to effective antineoplastic agents. Here we report a novel C-terminal Hsp90 inhibitor, designated KU675, that exhibits potent antiproliferative and cytotoxic activity along with client protein degradation without induction of the heat-shock response in both androgen-dependent and -independent prostate cancer cell lines. In addition, KU675 demonstrates direct inhibition of Hsp90 complexes as measured by the inhibition of luciferase refolding in prostate cancer cells. In direct binding studies, the internal fluorescence signal of KU675 was used to determine the binding affinity of KU675 to recombinant Hsp90α, Hsp90β, and Hsc70 proteins. The binding affinity (Kd) for Hsp90α was determined to be 191 μM, whereas the Kd for Hsp90β was 726 μM, demonstrating a preference for Hsp90α. Western blot experiments with four different prostate cancer cell lines treated with KU675 supported this selectivity by inducing the degradation of Hsp90α-dependent client proteins. KU675 also displayed binding to Hsc70 with a Kd value at 76.3 μM, which was supported in cellular by lower levels of Hsc70-specific client proteins on Western blot analyses. Overall, these findings suggest that KU675 is an Hsp90 C-terminal inhibitor, as well as a dual inhibitor of Hsc70, and may have potential use for the treatment of cancer.

MP54-13 MALNUTRITION STATUS AND AN INTERVENTION FOR MALNUTRITION IN PATIENTS UNDERGOING RADICAL CYSTECTOMY

INTRODUCTION AND OBJECTIVES: Underdiagnosing malnutrition in high-risk surgical patients is problematic. Rapid skeletal muscle wasting is a serious and common complication following radical cystectomy (RC) to treat muscle-invasive bladder cancer. Specialized immunonutrition (SIM) intake before and after RC may help counteract muscle wasting in the post-operative period. METHODS: Men with muscle-invasive cancer scheduled for radical cystectomy were randomly assigned to oral SIM providing supplemental L-arginine, fish oil, vitamin A, and nucleotides (n 1⁄4 14) or a calorieand nitrogen-matched oral nutrition supplement [ONS (n 1⁄4 15)] for 5 days before and 5 days after RC. Malnutrition was assessed by a trained research team using the Patient-Generated Subjective Global Assessment (PG-SGA) tool. Dual Energy X-Ray Absorptiometry scans were obtained at baseline, 14 days, and 30 days after surgery to calculate relative skeletal muscle index (RSMI). Discrepancies between the malnutrition diagnoses using the PG-SGA tool and the UHC Billing database on the same patients were compared. RESULTS: Using the PG-SGA tool, 21% of patients were identified as well nourished, 66% were moderately malnourished, and 14% were severely malnourished prior to RC. Billed and coded data showed 86% of patients were well nourished, 7% were moderately malnourished, and 7% were severely malnourished prior to RC. Relative Skeletal Muscle Index (RSMI) was better preserved in the SIM group at 14 days (7% vs. 17% in the ONS group). CONCLUSIONS: The large discrepancy between patients identified as malnourished using the PG-SGA as compared to the billing data suggests a problem of underdiagnosing malnutrition in this population. Improving nutrition status through specialized immunonutrition could be a low risk, high-impact means of counteracting muscle wasting after RC for bladder cancer.

MP15-16 THE ASSOCIATION OF AGE WITH PERIOPERATIVE AND CLINICOPATHOLOGIC OUTCOMES FOLLOWING RADICAL CYSTECTOMY FOR NON-MUSCLE INVASIVE BLADDER CANCER

INTRODUCTION AND OBJECTIVES: Non muscle invasive bladder cancer is a recurrent and progressive disease; currently we are unable to forecast recurrence in the individual patient. Recently we developed a mathematical model that found NLR as a good prognostic tool. The model was tested retrospectively in an additional study and found accurate too. The aim of the current study is to assess its accuracy to forecast recurrence prospectively in patients with NMIBC METHODS: All patients admitted to bladder tumor resection (TURBT) and agreed to participate in the study had blood drawn for blood count 24 hours prior to surgery. Patients with non-muscle invasive tumor were recruited and prospectively followed. Patients had urine cytology and cystoscopy every 3 months for 2 years following resection. Time to recurrence and recurrence free of tumor were recorded. Statistical analysis was done with X2 test for categorical parameters and T test for serial parameters. Logistic regression was performed to forecast prognosis. RESULTS: 123 patients were recruited, mean age was 71 years, all patients had at least 1 year follow up. Twenty nine patients (23.6%) experienced biopsy proven tumor recurrence. The mean time for recurrence was 7.38 months.Neutrophil to Lymphocyte rate > 2 showed direct statistically significant correlation with tumor recurrence (p1⁄40.038), tumor stage showed the same correlation (p1⁄40.048). The specificity of our recurrence forecasting model was 96.8%. EORTC score did not demonstrate significance between the recurrent and nonrecurrent groups. CONCLUSIONS: Our mathematical model that found NLR as a prognostic tool in patients with NMIBC was tested for the first time prospectively. The model demonstrated its ability to forecast recurrence more accurately then tumor stage grade and EORT score in the individual patient with NMIBC.The main limitation of this work is the relatively low number of patients.

MP64-20 COMPLETE PATHOLOGIC RESPONSE TO NEOADJUVANT CHEMOTHERAPY FOR BLADDER CANCER: THE EFFECT OF PRE-TREATMENT CLINICAL STAGE

INTRODUCTION AND OBJECTIVES: We evaluated patients followed with non-muscle invasive, nested variant of urothelial carcinoma and compared progression and survival outcomes to patients with pure urothelial carcinoma. METHODS: We identified 4086 patients with bladder cancer who presented with pTa, pTis, or pT1 at diagnosis. Among this cohort, there were 3897 patients with pure urothelial carcinoma and 92 patients were found to have nested variant features at some point during followup. In order to assess whether there is a difference in progression-free survival (PFS) between NMIBC patients with pure urothelial carcinoma and those with nested features, we utilized multivariable Cox proportional hazards models adjusting for gender, age and tumor stage (pT1 vs pTa/pTis) at diagnosis. A univariate Cox proportional hazards model was used to assess difference in overall survival (OS) based on nested or pure urothelial carcinoma histology. RESULTS: On univariate analysis, nested variant was found to be significantly associated with poorer PFS (HR 6.25; 95% C.I. 4.52, 8.65; p < 0.0001). Hazard ratios were similar after adjusting for standard predictors on multivariable analysis, (HR: 4.12; 95% C.I. 2.98, 5.69; p < 0.0001). Figure 1 displays the PFS curves for UC vs. nestedfeatures estimated from our multivariable Cox proportional hazard models based on the covariate values of the average patient with nested features: 65 year old, male patient with a diagnostic tumor stage of pT1. On univariate analysis, having nested variant was found to be significantly associated with poorer OS (HR 1.97; 95% C.I. 1.45, 2.67; p < 0.0001). CONCLUSIONS: Non-muscle invasive, nested variant of urothelial carcinoma is associated with significantly poorer PFS and OS compared with pure urothelial carcinoma, suggesting that these patients should be considered for more aggressive surveillance and earlier treatment.