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1.  Bladder Preservation Therapy for Muscle-Invading Bladder Cancers on Radiation Therapy Oncology Group Trials 8802, 8903, 9506, and 9706: Vascular Endothelial Growth Factor B Overexpression Predicts for Increased Distant Metastasis and Shorter Survival 
The Oncologist  2013;18(6):685-686.
From 1988 to 1999, the Radiation Therapy Oncology Group (RTOG) conducted four prospective studies (8802, 8903, 9506, 9706) of patients with clinical stage T2–4a muscle-invasive bladder cancer. Treatment was selective bladder preservation using transurethral surgery (TURBT) plus cisplatin-based induction and consolidation chemoradiation regimens, reserving radical cystectomy for invasive tumor recurrence. We investigated vascular endothelial growth factor (VEGF) pathway biomarkers in this unique clinical dataset (median follow-up of 3.1 years).
A total of 43 patients with tissue available from the entry TURBT were included in this analysis. Expression of VEGF ligands and receptors were quantified and scored by the AQUA platform (HistoRX, now Genoptix, Carlsbad, CA) and analyzed after median split.
VEGF expression levels were not associated with increased rates of complete response to induction chemoradiation. Higher levels of cytoplasmic VEGF-B, VEGF-C, and VEGF-R2 were associated with decreased overall survival rates. The 3-year overall survival estimates for high and low expressers were 43.7% and 75% for VEGF-B cytoplasm (p = .01), 40.2% and 86.7% for VEGF-C cytoplasm (p = .01), and 49.7% and 66.7% for VEGF-R2 cytoplasm (p = .02). Higher expression levels of cytoplasm VEGF-B were associated with higher rates of distant failure (p = .01).
Although VEGF ligands and receptors do not appear to be associated with complete response to induction chemoradiation for muscle-invasive bladder cancer, we report significant associations with overall survival and distant failure for certain VEGF family members.
PMCID: PMC4063394  PMID: 23728940
2.  Late Pelvic Toxicity After Bladder-Sparing Therapy in Patients With Invasive Bladder Cancer: RTOG 89-03, 95-06, 97-06, 99-06 
Journal of Clinical Oncology  2009;27(25):4055-4061.
In selected patients with muscle-invasive bladder cancer, combined-modality therapy (transurethral resection bladder tumor [TURBT], radiation therapy, chemotherapy) with salvage cystectomy, if necessary, can achieve survival rates similar to radical cystectomy. We investigated late pelvic toxicity after chemoradiotherapy for patients treated on prospective protocols.
Patients and Methods
Between 1990 and 2002, 285 eligible patients enrolled on four prospective protocols (Radiation Therapy Oncology Group [RTOG] 8903, 9506, 9706, 9906) and 157 underwent combined-modality therapy, surviving ≥ 2 years from start of treatment with their bladder intact. Rates of late genitourinary (GU) and GI toxicity were assessed using the RTOG Late Radiation Morbidity Schema, with worst toxicity grade (scale 0 to 5) occurring ≥ 180 days after start of consolidation therapy reported for each patient. Persistence of toxicity was defined as grade 3+ toxicity not decreasing by at least one grade. Logistic and Cox regression analyses were performed to evaluate relationship between clinical characteristics, frequency, and time to late grade 3+ pelvic toxicity. Covariates included age, sex, stage, presence of carcinoma in situ, completeness of TURBT, and protocol.
Median follow-up was 5.4 years (range, 2.0 to 13.2 years). Seven percent of patients experienced late grade 3+ pelvic toxicity: 5.7% GU and 1.9% GI. In only one of nine patients did a grade 3+ GU toxicity persist. Notably there were no late grade 4 toxicities and no treatment-related deaths. None of the clinical variables studied predicted for late grade 3+ pelvic toxicity.
Rates of significant late pelvic toxicity for patients completing combined-modality therapy for invasive bladder cancer and retaining their native bladder are low.
PMCID: PMC2734419  PMID: 19636019
3.  MEK1/2 inhibitors and 17AAG synergize to kill human GI tumor cells in vitro via suppression of c-FLIP-s levels and activation of CD95 
Molecular cancer therapeutics  2008;7(9):2633-2648.
Prior studies have noted that inhibitors of MEK1/2 enhanced geldanamycin lethality in malignant hematopoietic cells by promoting mitochondrial dysfunction. The present studies focused on defining the mechanism(s) by which these agents altered survival in carcinoma cells. MEK1/2 inhibitors (PD184352; AZD6244 (ARRY-142886)) interacted in a synergistic manner with geldanamycins (17AAG, 17DMAG) to kill hepatoma and pancreatic carcinoma cells that correlated with inactivation of ERK1/2 and AKT and with activation of p38 MAPK; p38 MAPK activation was ROS-dependent. Treatment of cells with MEK1/2 inhibitors and 17AAG reduced expression of c-FLIP-s that was mechanistically connected to loss of MEK1/2 and AKT function; inhibition of caspase 8 or over-expression of c-FLIP-s abolished cell killing by MEK1/2 inhibitors and 17AAG. Treatment of cells with MEK1/2 inhibitors and 17AAG caused a p38 MAPK-dependent plasma membrane clustering of CD95 without altering the levels or cleavage of FAS ligand. In parallel, treatment of cells with MEK1/2 inhibitors and 17AAG caused a p38 MAPK-dependent association of caspase 8 with CD95. Inhibition of p38 MAPK or knock down of BID, FADD or CD95 expression suppressed MEK1/2 inhibitor and 17AAG lethality. Similar correlative data were obtained using a xenograft flank tumor model system. Our data demonstrate that treatment of tumor cells with MEK1/2 inhibitors and 17AAG induces activation of the extrinsic pathway and that suppression of c-FLIP-s expression is crucial in transduction of the apoptotic signal from CD95 to promote cell death.
PMCID: PMC2585522  PMID: 18790746
CD95; caspase; extrinsic; FLIP
4.  Lapatinib resistance in HCT116 cells is mediated by elevated MCL-1 expression, decreased BAK activation, and not by ERBB receptor mutation 
Molecular pharmacology  2008;74(3):807-822.
We have defined some of the mechanisms by which the kinase inhibitor Lapatinib kills HCT116 cells. Lapatinib inhibited radiation-induced activation of ERBB1/2, ERK1/2 and AKT, and radiosensitized HCT116 cells. Prolonged incubation of HCT116 cells with Lapatinib caused cell killing followed by outgrowth of Lapatinib adapted cells. Adapted cells were resistant to serum-starvation –induced cell killing and were cross resistant to multiple therapeutic drugs. Lapatinib was competent to inhibit basal and EGF-stimulated ERBB1 phosphorylation in adapted cells. Co-expression of dominant negative ERBB1 and dominant negative ERBB2 inhibited basal and EGF-stimulated ERBB1 and ERBB2 phosphorylation in parental cells. However in neither parental nor adapted cells did expression of dominant negative ERBB1 and dominant negative ERBB2 recapitulate the cell death promoting effects of Lapatinib. Adapted cells had increased expression of MCL-1, decreased expression of BAX, and decreased activation of BAX and BAK. Over-expression of BCL-XL protected parental cells from Lapatinib toxicity. Knock down of MCL-1 expression enhanced Lapatinib toxicity in adapted cells that was reverted by knock down of BAK expression. Inhibition of caspase function modestly reduced Lapatinib toxicity in parental cells whereas knock down of AIF expression suppressed Lapatinib toxicity. Thus in HCT116 cells Lapatinib adaptation can be mediated by altered expression of pro- and anti-apoptotic proteins that maintain mitochondrial function.
PMCID: PMC2574656  PMID: 18544666
Lapatinib; Ras; cell death
5.  Monte Carlo dose verification of prostate patients treated with simultaneous integrated boost intensity modulated radiation therapy 
To evaluate the dosimetric differences between Superposition/Convolution (SC) and Monte Carlo (MC) calculated dose distributions for simultaneous integrated boost (SIB) prostate cancer intensity modulated radiotherapy (IMRT) compared to experimental (film) measurements and the implications for clinical treatments.
Twenty-two prostate patients treated with an in-house SIB-IMRT protocol were selected. SC-based plans used for treatment were re-evaluated with EGS4-based MC calculations for treatment verification. Accuracy was evaluated with-respect-to film-based dosimetry. Comparisons used gamma (γ)-index, distance-to-agreement (DTA), and superimposed dose distributions. The treatment plans were also compared based on dose-volume indices and 3-D γ index for targets and critical structures.
Flat-phantom comparisons demonstrated that the MC algorithm predicted measurements better than the SC algorithm. The average PTVprostate D98 agreement between SC and MC was 1.2% ± 1.1. For rectum, the average differences in SC and MC calculated D50 ranged from -3.6% to 3.4%. For small bowel, there were up to 30.2% ± 40.7 (range: 0.2%, 115%) differences between SC and MC calculated average D50 index. For femurs, the differences in average D50 reached up to 8.6% ± 3.6 (range: 1.2%, 14.5%). For PTVprostate and PTVnodes, the average gamma scores were >95.0%.
MC agrees better with film measurements than SC. Although, on average, SC-calculated doses agreed with MC calculations within the targets within 2%, there were deviations up to 5% for some patient's treatment plans. For some patients, the magnitude of such deviations might decrease the intended target dose levels that are required for the treatment protocol, placing the patients in different dose levels that do not satisfy the protocol dose requirements.
PMCID: PMC2701954  PMID: 19527515
6.  OSU-03012 Stimulates PKR-Like Endoplasmic Reticulum-Dependent Increases in 70-kDa Heat Shock Protein Expression, Attenuating Its Lethal Actions in Transformed Cells 
Molecular pharmacology  2008;73(4):1168-1184.
We have further defined mechanism(s) by which 2-amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]-phenyl}acetamide [OSU-03012 (OSU)], a derivative of the cyclooxygenase-2 (COX2) inhibitor celecoxib but lacking COX2 inhibitory activity, kills transformed cells. In cells lacking expression of protein kinase R-like endoplasmic reticulum kinase (PERK-/-), the lethality of OSU was attenuated. OSU enhanced the expression of Beclin 1 and ATG5 and cleavage of pro-caspase 4 in a PERK-dependent fashion and promoted the Beclin 1- and ATG5-dependent formation of vacuoles containing LC3, followed by a subsequent caspase 4-dependent cleavage of cathepsin B and a cathepsin B-dependent formation of low pH intracellular vesicles; cathepsin B was activated and released into the cytosol and genetic suppression of caspase 4, cathepsin B, or apoptosis-inducing factor function significantly suppressed cell killing. In parallel, OSU caused PERK-dependent increases in 70-kDa heat shock protein (HSP70) expression and decreases in 90-kDa heat shock protein (HSP90) and Grp78/BiP expression. Changes in HSP70 expression were post-transcriptional. Knockdown or small-molecule inhibition of HSP70 expression enhanced OSU toxicity, and overexpression of HSP70 suppressed OSU-induced low pH vesicle formation and lethality. Our data demonstrate that OSU-03012 causes cell killing that is dependent on PERK-induced activation of multiple toxic proteases. OSU-03012 also increased expression of HSP70 in a PERK-dependent fashion, providing support for the contention that OSU-03012-induced PERK signaling promotes both cell survival and cell death processes.
PMCID: PMC2674576  PMID: 18182481

Results 1-6 (6)