Regulation of Fas-mediated apoptosis by N-ras in melanoma.

Oncogenic ras has been shown to downregulate Fas receptor expression and increase Fas ligand expression and thus contribute to resistance to Fas-mediated cell death in several cell types. The effects of ras on Fas-mediated apoptosis have not been studied in melanoma. We studied the effects of activated N-ras by measuring Fas, Fas ligand, and FLIP expression as well as susceptibility to Fas-ligand-induced cell death in transfectants of WM35, a radial growth phase human melanoma cell line. Based on quantitative polymerase chain reaction and fluorescence-activated cell sorter analysis, we found that the ras transfectants expressed less Fas mRNA and surface Fas receptor. Cr51 release cytotoxicity assays demonstrated less susceptibility to Fas-mediated apoptosis in ras transfectants, correlating with the Fas mRNA and protein expression results. Ras inhibition with the specific inhibitor FTI-277 showed that downregulation of Fas in the ras transfectants could be reversed. This correlates with cytotoxicity experiments showing that ras inhibition increases susceptibility to Fas-mediated apoptosis. The control transfectants expressed FLIP but ras did not affect FLIP expression. The control and ras transfectants did not express Fas ligand as demonstrated by reverse transcriptase polymerase chain reaction and fluorescence-activated cell sorter analysis. Cytotoxicity assays further confirmed that these melanoma ras transfectants do not express functional Fas ligand. These results suggest that ras contributes to tumor progression by decreasing susceptibility to Fas-mediated cell death at least in part through downregulation of Fas receptor at the transcriptional level.

Association of expression of CD44v6 with systemic anaplastic large cell lymphoma: comparison with primary cutaneous anaplastic large cell lymphoma.

CD44 is a ubiquitous multifunctional cell surface adhesion molecule family. High expression of the standard form, CD44s (CD44), and its variant form, CD44v6, has been reported to be associated with tumor dissemination in non-Hodgkin lymphoma. To evaluate the potential role of CD44 and/or CD44v6 in different entities of anaplastic large cell lymphoma (ALCL), 30 cases of systemic ALCL (sALCL; 20 cases) and primary cutaneous ALCL (cALCL; 10 cases) were compared for expression of CD44 and CD44v6 by immunohistochemical staining. Expression of CD44v6 also was analyzed with respect to expression of anaplastic lymphoma kinase (ALK) in sALCL. No difference of CD44 expression was noted between sALCL and cALCL In contrast, expression of CD44v6 was found in 18 (90%) of sALCL cases and in 5 (50%) of cALCL cases. There was no correlation between expression of CD44v6 and expression of ALK in sALCL. These results indicate that expression of CD44v6 rather than CD44 correlates with sALCL. Furthermore, these results suggest that CD44v6 and ALK may be independent predictors of risk for the systemic phenotype of ALCL.

Assessment of t(2;5)(p23;q35) translocation and variants in pediatric ALK+ anaplastic large cell lymphoma.

To evaluate t(2;5) and its variants, we studied 21 pediatric cases of anaplastic lymphoma kinase (ALK)+ anaplastic large cell lymphoma (ALCL) by using immunohistochemical staining, fluorescence in situ hybridization, cytogenetics, and reverse transcriptase-polymerase chain reaction. Results showed 7 (33%) cases with t(2;5), 6 (29%) with variant gene rearrangements, 7 (33%) with uncharacterized rearrangements, and 1 with ALK protein expression but no ALK rearrangement. Among 6 variant gene rearrangements, 1 had TPM4-ALK/t(2;19)(p23;p13) and 2 had inv(2) with the breakpoint proximate to ATIC-ALK and an unknown partner gene separately. The genetic features of the remaining 3 cases were as follows: ins(8;2) with an unknown partner gene; conversion from ALK- at diagnosis to ALK+ at recurrence with unspecified gene rearrangement; complex karyotype without involvement of 2p23, suggesting a cryptic translocation. Concordance between different laboratory results varied from 47% to 81%. These data suggest that ALK variants are not uncommon and underscore the necessity of integrating immunohistochemical, cytogenetic, and molecular genetic approaches to detect, characterize, and confirm t(2;5) and its variant translocations.

Phase 2 trial of erlotinib with or without PF-3512676 (CPG 7909, a Toll-like receptor 9 agonist) in patients with advanced recurrent EGFR-positive non-small cell lung cancer.

This phase 2 study assessed PF-3512676 plus erlotinib in patients with epidermal growth factor receptor-positive advanced non-small cell lung cancer after prior chemotherapy failure. Patients were randomized 1:1 to PF-3512676 (0.20 mg/kg injected subcutaneously once weekly) plus erlotinib (150 mg daily) or erlotinib alone. The primary objective was to estimate progression-free survival (PFS). Patients received PF-3512676 plus erlotinib (n = 18) or erlotinib alone (n = 21). The study was halted because an unplanned interim analysis indicated that large improvement in PFS with addition of PF-3512676 would be unlikely. In the PF-3512676-plus-erlotinib and erlotinib-alone arms, median PFS was 1.6 and 1.7 mo (hazard ratio, 1.00; 95% confidence interval, 0.5-2.0; P = 0.9335), respectively. Salient grade ≥ 3 adverse events in PF-3512676-plus-erlotinib and erlotinib-alone arms were diarrhea (5/0), dyspnea (5/6), fatigue (4/1), other flu-like symptoms (2/0), anemia (2/1), and lymphocytopenia (based on laboratory values, 1/4). Adding PF-3512676 to erlotinib did not show potential for increased progression-free survival over erlotinib alone in patients with advanced recurrent epidermal growth factor receptor-positive non-small cell lung cancer.

Opportunities and challenges in the development of experimental drug combinations for cancer.

It is becoming increasingly evident that cancers are dependent on a number of altered molecular pathways and can develop diverse mechanisms of resistance to therapy with single agents. Therefore, combination regimens may provide the best hope for effective therapies with durable effects. Despite preclinical data to support this notion, there are many challenges to the development of targeted combinations including scientific, economic, legal, and regulatory barriers. A discussion of these challenges and identification of models and best practices are presented with intent of aiding the research community in addressing real and perceived barriers to the development of combination therapies for cancer.

Randomized phase III trial of paclitaxel/carboplatin with or without PF-3512676 (Toll-like receptor 9 agonist) as first-line treatment for advanced non-small-cell lung cancer.

PURPOSE: This phase III study examined efficacy of the synthetic Toll-like receptor 9-activating oligodeoxynucleotide PF-3512676 in combination with standard paclitaxel/carboplatin chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Chemotherapy-naive patients with stage IIIB or IV NSCLC were randomly assigned (1:1) to receive up to six courses of paclitaxel/carboplatin (intravenous paclitaxel 200 mg/m(2) and carboplatin at area under the [concentration-time] curve 6 on day 1 of a 3-week cycle) alone (control arm) or in combination with 0.2 mg/kg subcutaneous PF-3512676 on days 8 and 15 (investigational arm). Primary end point was overall survival (OS). RESULTS: Baseline demographics were similar across arms (N = 828). Most patients (88%) had stage IV disease. Median OS and median progression-free survival (PFS) were similar (OS: investigational arm, 10.0 months v control arm, 9.8 months; P = .56; PFS: investigational arm, 4.8 months v control arm, 4.7 months; P = .79). Most commonly reported PF-3512676-related adverse events (AEs) were mild-to-moderate local injection site reactions, pyrexia, and flu-like symptoms. In the investigational arm, grades 3 to 4 AEs, including neutropenia, thrombocytopenia, and anemia, were more frequent, and more patients had one or more sepsis-related AEs versus controls (17 v 3). At first interim analysis, the Data Safety Monitoring Committee recommended study discontinuation because of lack of incremental efficacy and more sepsis-related serious AEs in the PF-3512676 arm. Administration of PF-3512676, but not chemotherapy, was halted. CONCLUSION: Addition of PF-3512676 to paclitaxel/carboplatin did not improve OS or PFS versus paclitaxel/carboplatin alone for first-line treatment of patients with advanced NSCLC but did increase toxicity. This regimen cannot be recommended for treating patients with advanced NSCLC.

Advanced small cell carcinoma of the ovary in a pediatric patient with long-term survival and review of the literature.

Advanced small cell carcinoma of the ovary is very aggressive tumor with an overall poor prognosis. The authors describe an 11-year-old girl who presented with advanced-stage disease. She was treated with gross total surgical resection and multiagent chemotherapy and remains free of disease more than 2.5 years from diagnosis. The treatment regimen is discussed in detail and was well tolerated, with minimal toxicity. This is the first case report of a pediatric patient with advanced-stage disease to achieve long-term survival.

Combined computed tomography-guided radiofrequency ablation and brachytherapy in a child with multiple recurrences of Wilms' tumor.

BACKGROUND: Treatment of relapsed Wilms' tumor remains a challenge. We describe a case of an 11-year-old girl with multiply relapsed Wilms' tumor in whom combined percutaneous computed tomography (CT)-guided radiofrequency ablation and brachytherapy directed at a retroperitoneal tumor mass resulted in pain palliation and local tumor control. OBSERVATIONS: Over the course of few weeks, her requirement for narcotic pain medications dramatically decreased. A contrast-enhanced CT scan obtained at 8 months after the procedure showed no evidence for local tumor recurrence. However, she subsequently developed myelodysplasia with evolution into leukemia, presumably secondary to chemotherapy, and died 9.5 months after the procedure. CONCLUSION: Combined CT-guided radiofrequency ablation and brachytherapy is a promising new minimally invasive palliative treatment of recurrent Wilms' tumor.

Fas ligand-dependent suppression of autoimmunity via recruitment and subsequent termination of activated T cells.

Signals transmitted by binding of Fas ligand (FasL) to the Fas receptor (CD95/Apo-1) have pleiotropic effects on cellular function that present opportunities for therapeutic applications. For example, depending on the circumstances, overexpression of FasL can enhance, prevent, or reverse growth of spontaneous or transplantable tumors. Furthermore, local administration of FasL into a single paw in susceptible mice protects from or reduces the severity of collagen-induced arthritis (CIA) in all paws. Here, we define mechanisms that mediate systemic protection induced by locally delivered FasL. Protection is not solely dependent on local interactions between Fas and FasL, but rather requires induction of a paradoxical inflammatory response that not only destroys Fas-resistant tumors, but also recruits motile, activated, Fas-bearing T cells that are Fas sensitive. We demonstrate by following the antigen-specific recruitment and subsequent termination of transgenic T cells that activated T cells, including autoreactive cells responsible for CIA, are eliminated within this inflammatory environment through the overexpressed FasL. The nature of the inflammatory response, which depends on the Fas ligand being cell bound and not soluble, and the magnitude of FasL expression within the inflammatory milieu are essential for this effect, as arthritogenic inflammation alone resulting from CIA induction is insufficient to ameliorate the disease or eliminate antigen-specific T cells, even upon systemic delivery of soluble FasL. These data show that gene delivery of membrane-bound FasL can effectively recruit and eliminate autoreactive T cells.