Citations

Abstract AZD6244 (ARRY 142886) is a potent and selective mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitor currently in early clinical trials. We examined the activity of AZD6244 in a panel of non–small cell lung cancer and a panel of cell lines representing many cancer types using in vitro growth assays. AZD6244 induced G0-G1 cell cycle arrest in sensitive cell lines that primarily included cells containing the BRAF V600E mutation. In these cells, G0-G1 arrest is accompanied by the up-regulation of the cell cycle inhibitors p21WAF1 and p27Kip1 and down-regulation of cyclin D1. In the majority of cell lines tested, including those with K-ras or non-V600E BRAF mutations, AZD6244 induced the accumulation of phospho-MEK, an effect not observed in the most sensitive BRAF V600E-containing cells. Accumulation of phospho-MEK in non–V600E-containing cell lines is due to abrogation of negative feedback pathways. BRAF V600E disrupts negative feedback signaling, which results in enhanced baseline phospho-MEK expression. Exogenous expression of BRAF V600E disrupts feedback inhibition but does not sensitize cells to AZD6244. Specific suppression of endogenous BRAF V600E does not confer resistance to AZD6244 but enhances sensitivity to AZD6244. Thus, our findings show that BRAF V600E marks cells with an in vitro requirement for MAPK signaling to support proliferation. These cells are exquisitely sensitive to AZD6244 (IC50, <100 nmol/L), have high baseline levels of phospho-MEK, and lack feedback inhibition between ERK and Raf. These data suggest an approach to identifying cells that may be sensitive to AZD6244 and other MEK inhibitors. [Cancer Res 2008;68(15):6145–53]

Abstract B7x is the newest member of the B7-CD28 family and is thought to dampen immune responses via negative costimulation. Tumor expression of B7x was recently described in renal cell carcinoma (RCC) and was associated with poor outcome. We developed an assay to detect serum-soluble B7x (sB7x) and investigated 101 patients with clear cell RCC who underwent nephrectomy between 2003 and 2007. For controls, we obtained serum from 101 sex-matched blood donors within the same age range. Following an ELISA for sB7x, detectable levels (>0.1 ng/mL) of sB7x were observed in 53 RCC patients compared with 18 controls (P < 0.001). Median (range) concentrations of sB7x for RCC patients and controls were 14.4 ng/mL (0.1–56.9) and 2.7 ng/mL (0.2–37.1), respectively. For RCC patients with detectable sB7x, median levels were significantly higher for patients with a tumor thrombus (19.2 versus 6.6 ng/mL; P = 0.007), positive lymph nodes (41.3 versus 10.3 ng/mL; P = 0.018), and distant metastases at nephrectomy (43.3 versus 8.5 ng/mL; P = 0.002) and tended to be higher in patients with high-grade tumors (18.8 versus 8.5; P = 0.090). Additionally, median sB7x levels for tumor-node-metastasis stage I to IV RCC were 6.6, 10.3, 14.5, and 43.3 ng/mL, respectively (P = 0.012). In this first evaluation of sB7x in RCC, we show that RCC patients are more likely to have detectable sB7x compared with controls and higher sB7x levels correlate with advanced tumor stage. These early results merit further investigation of this serum marker for potential diagnostic and prognostic purposes. [Cancer Res 2008;68(15):6054–8]

Abstract Purpose: Aberrant expression of T-cell coregulatory molecules has been investigated as a mechanism by which certain cancers may evade host immune surveillance. We evaluated expression of the T-cell coregulators B7-H1, B7-H3, and PD-1 in urothelial cell carcinoma (UCC) of the bladder. Experimental Design: Immunohistochemistry for B7-H1, B7-H3, and PD-1 was done on paraffin-embedded sections from 318 consecutive patients with UCC who underwent radical cystectomy. Expression was correlated with clinicopathologic outcomes and postoperative survival. Results: B7-H3 was widely expressed in UCC, as 222 of 314 (70.7%) tumors showed positive staining. Expression of B7-H3 in UCC was significantly increased compared with adjacent, nontumor urothelium, as a median of 70% of tumor cells expressed B7-H3, compared with 20% of cells in nontumor specimens (P < 0.001). The increase in B7-H3 expression was independent of tumor stage (P = 0.13). Expression of B7-H1 by UCC tumors (P < 0.001) and PD-1 by tumor-infiltrating lymphocytes (P = 0.012) were significantly associated with increased pathologic stage. Patients who had received intravesical bacillus Calmette-Guerin before cystectomy tended to show increased expression of B7-H3 (P = 0.023) and PD-1 (P = 0.071) but were less likely to express B7-H1 (P = 0.027). Moreover, for the subset of patients with organ-confined disease (n = 167), B7-H1 expression independently predicted all-cause mortality after cystectomy (hazard ratio, 3.18; 95% confidence interval, 1.74-5.79; P < 0.001). Conclusions: B7-H3 is highly expressed in UCC across tumor stages, whereas B7-H1 and PD-1 expression are associated with advanced disease. B7-H1 expression predicts mortality after cystectomy for patients with organ-confined tumors. These molecules may represent novel diagnostic or prognostic markers, as well as therapeutic targets, for patients with UCC.

Abstract Purpose: To assess the effects of external beam radiotherapy (EBRT) on adenoviral-mediated transgene expression in vitro and in vivo and to define an optimal strategy for combining sodium iodide symporter (NIS)–mediated 131I therapy with EBRT. Experimental Design: Expression of reporter genes [NIS, green fluorescent protein (GFP), β-galactosidase (lacZ), and luciferase (Luc)] from replication-deficient adenoviruses was assessed in tumor cell lines under basal conditions and following irradiation. The effects of viral multiplicity of infection (MOI) and EBRT dose on the magnitude and duration of gene expression were determined. In vivo studies were done with Ad-CMV-GFP and Ad-RSV-Luc. Results: EBRT increased NIS, GFP, and β-galactosidase expression in colorectal, head and neck, and lung cancer cells. Radiation dose and MOI were important determinants of response to EBRT, with greatest effects at higher EBRT doses and lower MOIs. Radiation exerted both transductional (through increased coxsackie-adenoviral receptor and integrin αv) and nontransductional effects, irrespective of promoter sequence (CMV, RSV, hTR, or hTERT). Analysis of the schedule of EBRT followed by viral infection revealed maximal transduction at 24 hours. Radiation maintained increasing radioiodide uptake from Ad-hTR-NIS over 6 days, in direct contrast to reducing levels in unirradiated cells. The effects of EBRT in increasing and maintaining adenovirus-mediated transgene expression were also seen in vivo using GFP- and luciferase-expressing adenoviral vectors. Conclusions: Radiation increased the magnitude and duration of NIS gene expression from replication-deficient adenoviruses. The transductional effect is maximal at 24 hours, but radioiodide uptake is maintained at an elevated level over 6 days after infection.

Abstract Pathogenic causes underlying nonischemic cardiomyopathies are increasingly being resolved, yet repair therapies for these commonly heritable forms of heart failure are lacking. A case in point is human dilated cardiomyopathy 10 (CMD10; Online Mendelian Inheritance in Man #608569), a progressive organ dysfunction syndrome refractory to conventional therapies and linked to mutations in cardiac ATP-sensitive K+ (KATP) channel subunits. Embryonic stem cell therapy demonstrates benefit in ischemic heart disease, but the reparative capacity of this allogeneic regenerative cell source has not been tested in inherited cardiomyopathy. Here, in a Kir6.2-knockout model lacking functional KATP channels, we recapitulated under the imposed stress of pressure overload the gene-environment substrate of CMD10. Salient features of the human malignant heart failure phenotype were reproduced, including compromised contractility, ventricular dilatation, and poor survival. Embryonic stem cells were delivered through the epicardial route into the left ventricular wall of cardiomyopathic stressed Kir6.2-null mutants. At 1 month of therapy, transplantation of 200,000 cells per heart achieved teratoma-free reversal of systolic dysfunction and electrical synchronization and halted maladaptive remodeling, thereby preventing end-stage organ failure. Tracked using the lacZ reporter transgene, stem cells engrafted into host heart. Beyond formation of cardiac tissue positive for Kir6.2, transplantation induced cell cycle activation and halved fibrotic zones, normalizing sarcomeric and gap junction organization within remuscularized hearts. Improved systemic function induced by stem cell therapy translated into increased stamina, absence of anasarca, and benefit to overall survivorship. Embryonic stem cells thus achieve functional repair in nonischemic genetic cardiomyopathy, expanding indications to the therapy of heritable heart failure. Disclosure of potential conflicts of interest is found at the end of this article.

Abstract Rationale An efficacious medical therapy for idiopathic pulmonary fibrosis (IPF) remains elusive. Objectives To explore the efficacy and safety of etanercept in the treatment of IPF. Methods This was a randomized, prospective, double-blind, placebo-controlled, multicenter exploratory trial in subjects with clinically progressive IPF. Primary endpoints included changes in the percentage of predicted FVC and lung diffusing capacity for carbon monoxide corrected for hemoglobin (DlCOHb) and change in the alveolar to arterial oxygen pressure difference P(a–a)O2 at rest from baseline over 48 weeks. Measurements and Main Results Eighty-eight subjects received subcutaneous etanercept (25 mg) or placebo twice weekly as their sole treatment for IPF. No differences in baseline demographics and disease status were detected between treatment groups; the mean time from first diagnosis was 13.6 months and mean FVC was 63.9% of predicted. At 48 weeks, no significant differences in efficacy endpoints were observed between the groups. A nonsignificant reduction in disease progression was seen in several physiologic, functional, and quality-of-life endpoints among subjects receiving etanercept. There was no difference in adverse events between treatment groups. Conclusions In this exploratory study in patients with clinically progressive IPF, etanercept was well tolerated. Although there were no differences in the predefined endpoints, a decreased rate of disease progression was observed on several measures. Further evaluation of TNF antagonists in the treatment of IPF may be warranted. Clinical trial registered with www.clinicaltrials.gov (NCT 00063869).

Transfer of pectoralis major has evolved as the most favoured option for the management of the difficult problem of irreparable tears of subscapularis. We describe our experience with this technique in 30 patients divided into three groups. Group I comprised 11 patients with a failed procedure for instability of the shoulder, group II included eight with a failed shoulder replacement and group III, 11 with a massive tear of the rotator cuff. All underwent transfer of the sternal head of pectoralis major to restore the function of subscapularis. At the latest follow-up pain had improved in seven of the 11 patients in groups I and III, but in only one of eight in group II. The subjective shoulder score improved in seven patients in group I, in one in group II and in six in group III. The mean Constant score improved from 40.9 points (28 to 50) in group I, 32.9 (17 to 47) in group II and 28.7 (20 to 42) in group III pre-operatively to 60.8 (28 to 89), 41.9 (24 to 73) and 52.3 (24 to 78), respectively. Failure of the tendon transfer was highest in group II and was associated with pre-operative anterior subluxation of the humeral head. We conclude that in patients with irreparable rupture of subscapularis after shoulder replacement there is a high risk of failure of transfer of p?ctoralis major, particularly if there is pre-operative anterior subluxation of the humeral head.