Analysis of the intensity of immune cell infiltration and immunoreactivity of RCAS1 in diffuse large B-cell lymphoma of the palatine tonsil and its microenvironment

Non-Hodgkin lymphoma of Waldeyer's ring constitutes a small percentage of cases of palatine tonsil malignancies and its precise etiology remains unknown. RCAS1 (receptor cancer-binding antigen expressed on SiSo cells) has been demonstrated to be associated with poor prognosis, the development of lymph node metastases and participation in tumor microenvironment remodeling. Our aim is to analyze the potential role of RCAS1 expression in the tumor and tumor microenvironment in the development of early-stage palatine tonsil B-cell lymphomas. We selected 20 patients and analyzed tissue samples from the lymphoma and tumor microenvironment of each patient and from a reference group of 20 patients with chronic tonsillitis. The presence of RCAS1 protein immunoreactivity was demonstrated in 65% of the examined tissue samples of diffuse large B-cell lymphoma and in 25% of the analyzed stromata in which it was exhibited by CD68-positive cells identified as macrophages and dispersed throughout the stroma. RCAS1 immunoreactivity in the lymphoma tissue samples remained at a level comparable with that of the reference and was significantly higher in these samples than in those from the stroma. Chronic inflammation of the palatine tonsils thus results in intensive infiltration by various types of immune system cells and in excessive RCAS1 immunoreactivity, both of which confirm the important regulatory role of RCAS1 in the immune response in the mucosa-associated lymphatic tissue of Waldeyer's ring. RCAS1 seems to be involved in creating tumor-induced inflammation in the tumor and its microenvironment.

Escalation to weekly dosing recaptures response in adalimumab-treated patients with moderately to severely active ulcerative colitis

BACKGROUND

Patients with moderately to severely active ulcerative colitis occasionally do not respond to or lose initial response to maintenance dosing of anti-TNF therapy.

AIM

To report the efficacy of escalation from every other week (EOW) to weekly adalimumab dosing in patients from the clinical trial ULTRA 2 (NCT00408629), by week 8 response (i.e. response after adalimumab induction therapy).

METHODS

Week 52 remission, response, and mucosal healing rates were assessed in ULTRA 2 adalimumab-randomised patients who escalated to weekly dosing. Patients were stratified by week 8 response per partial Mayo score. Kaplan-Meier and logistic regression analyses estimated time to weekly dosing and defined predictors of escalation to weekly dosing, respectively. Adverse events were reported for patients receiving open-label adalimumab.

RESULTS

The rate of escalation to weekly dosing was 16.3% (20/123) for week 8 responders and 38.4% (48/125) for week 8 nonresponders. Week 52 remission, response and mucosal healing rates with weekly dosing were 20%, 45%, and 45% for week 8 responders and 2.1%, 25% and 29.2% for nonresponders, respectively (NRI). The median time to weekly dosing was 288 days for week 8 nonresponders and not estimable for responders. Prior anti-TNF use was a significant predictor of escalation to weekly dosing. Treatment-emergent adverse event rates were similar for patients receiving open-label EOW or weekly adalimumab.

CONCLUSIONS

Escalation to weekly adalimumab dosing demonstrated clinical benefits for patients who lost response to therapy and may be beneficial for patients not initially responding to induction therapy. No new safety risks were identified with weekly dosing.

One-year maintenance outcomes among patients with moderately-to-severely active ulcerative colitis who responded to induction therapy with adalimumab: subgroup analyses from ULTRA 2

BACKGROUND

Patients with moderately-to-severely active ulcerative colitis (UC) are unlikely to continue anti-TNF therapy in the absence of early therapeutic response.

AIM

To assess week 52 efficacy, safety and benefit/risk balance of adalimumab treatment in patients with moderately-to-severely active UC failing conventional therapy who achieved clinical response at week 8 in the 52-week ULTRA 2 trial.

METHODS

Patients randomised to adalimumab (160/80 mg, week 0/2; 40 mg, every other week thereafter) in ULTRA 2 who achieved clinical response at week 8 per partial Mayo score (Mayo score without endoscopy subscore) were assessed for week 52 clinical remission, clinical response, mucosal healing, steroid-free remission and steroid discontinuation rates, overall and by prior anti-TNF use. Benefit/risk balance for the overall ITT population (regardless of week 8 responder status) was assessed using 'net efficacy adjusted for risk' (NEAR) odds ratios. Safety was assessed using adverse event rates.

RESULTS

Of 248 adalimumab-treated patients, 123 (49.6%) achieved clinical response at week 8. Of these, 30.9%, 49.6%, and 43.1% achieved clinical remission, clinical response, and mucosal healing, respectively, at week 52. Of the week 8 responders using corticosteroids at baseline (N = 90), 21.1% achieved steroid-free remission and 37.8% were steroid-free at week 52. NEAR odds ratios indicated a positive benefit/risk balance for achievement of week 8 and week 52 response or remission without serious adverse events or serious infections. No safety concerns were identified.

CONCLUSIONS

Adalimumab treatment was associated with a positive benefit/risk balance in the overall population of patients with moderately-to-severely active ulcerative colitis in ULTRA 2; early response was predictive of a positive outcome at 1 year (NCT00408629).

Hollow fiber bioartificial liver utilizing collagen-entrapped porcine hepatocyte spheroids

A xenogeneic hollow fiber bioreactor utilizing collagen-entrapped dispersed hepatocytes has been developed as an extracorporeal bioartificial liver (BAL) for potential treatment of acute human fulminant hepatitis. Prolonged viability, enhanced liver-specific functions, and differentiated state have been observed in primary porcine hepatocytes cultivated as spheroids compared to dispersed hepatocytes plated on a monolayer. Entrapment of spheroids into the BAL can potentially improve performance over the existing device. Therefore, studies were conducted to evaluate the feasibility of utilizing spheroids as the functionally active component of our hybrid device. Confocal microscopy indicated high viability of spheroids entrapped into cylindrical collagen gel. Entrapment of spheroids alone into collagen gel showed reduced ability to contract collagen gel. By mixing spheroids with dispersed cells, the extent of collagen gel contraction was increased. Hepatocyte spheroids collagen-entrapped into BAL devices were maintained for over 9 days. Assessment of albumin synthesis and ureagenesis within a spheroid-entrapment BAL indicated higher or at least as high activity on a per-cell basis compared to a dispersed hepatocyte-entrapment BAL device. Clearance of 4-methylumbelliferone to its glucuronide was detected throughout the culture period as a marker of phase II conjugation activity. A spheroid-entrapment bioartificial liver warrants further studies for potential human therapy. (c) 1996 John Wiley & Sons, Inc.

Development of a bioartificial liver employing xenogeneic hepatocytes

Liver failure is a major cause of mortality. A bioartificial liver (BAL) employing isolated hepatocytes can potentially provide temporary support for liver failure patients. We have developed a bioartificial liver by entrapping hepatocytes in collagen loaded in the luminal side of a hollow fiber bioreactor. In the first phase of development, liver-specific metabolic activities of biosynthesis, biotransformation and conjugation were demonstrated. Subsequently anhepatic rabbits were used to show that rat hepatocytes continued to function after the BAL was linked to the test animal. For scale-up studies, a canine liver failure model was developed using D-galactosamine overdose. In order to secure a sufficient number of hepatocytes for large animal treatment, a collagenase perfusion protocol was established for harvesting porcine hepatocytes at high yield and viability. An instrumented bioreactor system, which included dissolved oxygen measurement, pH control, flow rate control, an oxygenator and two hollow fiber bioreactors in series, was used for these studies. An improved survival of dogs treated with the BAL was shown over the controls. In anticipated clinical applications, it is desirable to have the liver-specific activities in the BAL as high as possible. To that end, the possibility of employing hepatocyte spheroids was explored. These self-assembled spheroids formed from monolayer culture exhibited higher liver-specific functions and remained viable longer than hepatocytes in a monolayer. To ease the surface requirement for large-scale preparation of hepatocyte spheroids, we succeeded in inducing spheroid formation in stirred tank bioreactors for both rat and porcine hepatocytes. These spheroids formed in stirred tanks were shown to be morphologically and functionally indistinguishable from those formed from a monolayer. Collagen entrapment of these spheroids resulted in sustaining their liver-specific functions at higher levels even longer than those of spheroids maintained in suspension. For use in the BAL, a mixture of spheroids and dispersed hepatocytes was used to ensure a proper degree of collagen gel contraction. This mixture of spheroids and dispersed cells entrapped in the BAL was shown to sustain the high level of liver-specific functions. The possibility of employing such a BAL for improved clinical performance warrants further investigations.

Combined analysis of two phase II trials of imatinib in advanced dermatofibrosarcoma protuberans (DFSP)

10520

Background: DFSP is an infiltrative, low-grade, dermal tumor with propensity to recur locally and occasionally metastasize. Translocation between COL1A1 on chromosome 17 and PDGFB on chromosome 22, which results in transcriptional upregulation of PDGFB, is characteristic of DFSP. Autocrine/paracrine PDGFB-mediated activation of PDGFRB drives DFSP proliferation. Two distinct phase II trials of imatinib in patients (pts) with locally advanced or metastatic DFSP were conducted, 1 in North America (SWOG) with confirmed objective response rate and 1 in Europe (EORTC) with 14 week progression-free rate as primary end-points. Methods: Pts with locally advanced or metastatic DFSP were eligible. In the EORTC trial confirmation of t(17;22) by FISH was prospectively required for participation, imatinib was started at 400mg bid, surgery was undertaken after 14 weeks if feasible and response was assessed at 14 weeks. Full accrual was to be 44 pts in one step. In the SWOG trial confirmation of t(17;22) by RT-PCR was performed after enrollment, imatinib was started at 400mg daily and response was assessed every 8 weeks. Full accrual was to be 40 pts in 2 steps. Results: 16 pts were enrolled in EORTC and 8 pts enrolled in SWOG trial. The studies were closed early because of slow accrual and regulatory approval of imatinib in DFSP. Pts age ranged from 24 to 70 yrs, DFSP was located on head/neck, trunk and extremity in 7, 11 and 6 pts, respectively, ranged in size from 1.2–49 cm and was classic, pigmented and fibrosarcomatous DFSP in 13, 1 and 7 pts, respectively. One patient did not have DFSP on central review, lacked t(17;22) and thus was ineligible. Metastases were present in 7 pts involving lung in 6 pts. 11 pts (46%) had partial response, 9 pts had stable disease and 4 pts had progressive disease as best response. Median time to progression was 1.7 yrs. Response and progression-free at 1 yr rates were similar between studies. Imatinib was stopped in 11 pts for progression, 1 pt for toxicity, 2 pts resected free of gross disease and 1 pt withdrew. Conclusions: Imatinib is active in DFSP harboring t(17;22) with an objective response rate approaching 50% and is active in fibrosarcomatous DFSP. Response rates and time to progression did not appear to differ between pts taking 400 mg daily versus 400 mg bid.

[Table: see text]

Simultaneous gastrointestinal stromal tumor (GIST) and desmoid fibromatosis (DF)

10568

Background: Desmoid Fibromatosis (DF) is one of a group of rare fibrous tissue proliferations (2–4 cases per year per million) which tend to be locally aggressive but have no propensity for metastasis. Gastrointestinal Stromal Tumor (GIST) is the most common mesenchymal tumors of the gastrointestinal tract and also rare (15–20 cases per year per million). Anecdotal reports of individuals with both diseases led us to investigate the number of patients at our institute with both types of cancer and their clinical, and histopathologic features. Methods: We identified four cases of GIST associated with DF at the M. D. Anderson Cancer Center between 1995 and 2008 using an IRB-approved protocol. Two more cases were identified from the patient database at the University of Helsinki. Results: Our patients were three men and three women aged from 39 to 66. Two patients were African Americans and 3 were Caucasians. In 5 cases, the GIST was diagnosed prior to the DF while one case had both tumors synchronous at presentation. The primary site of the GIST was gastric in 4 cases and the others were jejunal and mesenteric. Three patients had their DF occur in the surgical incision site mimicking a recurrence of GIST. The 3 others were intra-abdominal DF. There were no cases of DF occurring outside of the GI tract. One GIST patient was metastatic at presentation and one developed metastasis before DF was diagnosed. In 5 cases, imatinib mesylate was administered to the patients with partial response. In all cases KIT expression was observed immunohistochemically for GIST and but not for DF. Additionally, all cases of DF but no cases of GIST were found to have beta-catenin expression by immunohistochemistry. Conclusions: Our findings suggest that concurrent DF may occur in patients with GIST. Additionally, DF may mimic the recurrence of GIST or imatinib resistance. The association of these two sarcomas should be further explored.

No significant financial relationships to disclose.

Quantitative assessment of AKT activation in melanoma

9022

Background: Activating mutations of BRAF are highly prevalent in melanoma. However, multiple lines of evidence suggest that other pathways must also contribute to this disease. Activation of the PI3K-AKT pathway has been implicated in melanoma by mutations of NRAS and PTEN. Little direct information is known about the activation of the PI3K-AKT signaling pathway in melanoma, particularly in metastases. Methods: Proteins isolated from 99 frozen melanoma tumors were measured by reverse phase protein arrays (RRPA). A total of 53 proteins were assessed using validated antibodies. Activating mutations were assessed by mass spectroscopy-based genotyping. Activation of AKT (phospho-AKT) was compared to mutations and anatomic sites. Results: Samples from 75 regional metastases (LN or in-transit) and 24 distant metastases were analyzed. Technical replicates (same lysate) and biological replicates (same tumor, different lysates) demonstrated average Pearson correlation coefficients (r) of > 0.90, supporting the high technical quality of the analysis. A positive correlation was observed between levels of p-AKT and known AKT substrates p-GSK3 and p-TSC2 (p< 0.001 for both), and a negative correlation with PTEN (p < 0.01), supporting the maintenance of phosphorylation events during sample processing. Relative differences in p-AKT by RPPA were also confirmed by immunohistochemistry of representative tumors. Tumors with BRAF mutations had higher levels of p-AKT than tumors with NRAS mutations (p = 0.03). Indeed, tumors with NRAS mutations had p-AKT levels similar to tumors wild-type for BRAF and NRAS (p =0.73). Detailed analysis demonstrated that all tumors with elevated p-AKT had low PTEN expression. Similar results were seen in human melanoma cell lines. Analysis of distant metastases demonstrated that brain metastases had higher levels of p-AKT, p-GSK3, and p-TSC2, and lower levels of PTEN, compared to metastases to the lung or liver. Conclusions: AKT activation in melanoma correlates with PTEN expression, and does not correlate with NRAS mutation. Activation of the PI3K-AKT pathway may contribute to the aggressiveness of brain metastases. These findings have clinical implications for targeting this pathway, and demonstrate the feasibility and potential of RPPA analysis of signaling pathways in melanoma.

No significant financial relationships to disclose.

Selective activity of dasatinib for the most common KIT mutation in melanoma (L576P)

9019

Background: Point mutations in the KIT receptor tyrosine kinase gene have recently been identified in melanomas from mucosal, acral lentiginous (AL), and chronically sun-damaged (CSD) sites. An improved understanding of the molecular characteristics of melanoma-prevalent KIT mutations may lead to more effective therapeutic approaches. Methods: Human melanoma cell lines were screened by mass-spectroscopy based genotyping for KIT mutations, and a cell line with an endogenous L576P KIT mutation was identified. The cell line was treated in vitro with a panel of small molecule KIT inhibitors and the effects on cell viability were quantified. Molecular modeling of the interaction of the inhibitors with the KIT L576P mutant protein was determined to estimate binding affinity. PET/CT studies were performed on patients with mucosal melanoma harboring the L576P mutation pre- and post-dasatinib treatment. Results: We have identified the first human melanoma cell line with an endogenous L576P mutation, the most common KIT mutation in melanoma. In vitro testing demonstrated that this cell line is resistant to imatinib, nilotinib and sorafenib (0 - 1 uM), KIT inhibitors shown to be effective in non-melanoma cells with other KIT mutations. However, the mutant cell line was inhibited by dasatinib at concentrations as low as 10 nM, and was significantly more sensitive than melanoma cell lines with wild-type KIT (p = 0.02). No difference in sensitivity to Src inhibitors was observed, supporting that this sensitivity was due to KIT inhibition. Molecular modeling demonstrated that the L576P mutation induces structural changes in KIT that reduce the affinity for imatinib but not for dasatinib. Two metastatic melanoma patients with the L576P KIT mutation were treated with dasatinib, including one patient previously treated with imatinib. Both patients had marked reduction and elimination of tumor FDG- avidity by PET imaging after dasatinib treatment. Conclusions: This data supports that dasatinib has a selective inhibitory effect against the most common KITmutation in melanoma and has implications for the development of AL, CSD, and mucosal melanoma treatment.

[Table: see text]

Changes in chlorophyll fluorescence parameters and oxidative stress responses of bush bean genotypes for selecting contrasting acclimation strategies under water stress

Drought resistance of bean landraces was compared in order to select genotypes with either high morphological or high biochemical-physiological plasticity. The lines in the former group exhibited fast reduction in fresh and dry mass, decreased the water potential in primary leaves after irrigation withdrawal and the biomass mobilized from the senescent primary leaves was allocated into the roots. These genotypes had high frequency of primary leaf abscission under water stress. The genotypes with plasticity at the biochemical level maintained high water potential and photochemical efficiency, i.e. effective quantum yield, high photochemical (qP) and low non-photochemical (NPQ) quenching in primary leaves under drought stress. While superoxide dismutase activity was not influenced by the drought and the genotype, catalase activity increased significantly in the primary leaves of the genotypes with efficient biochemical adaptation. Lines with high morphological plasticity exhibited higher quaiacol peroxidase activity under drought. Proline may accumulate in both cases, thus it may be a symptom of protein degradation or a successful osmotic adaptation. On the basis of contrasting responses, the genetic material cannot be screened for a large-scale breeding program by a single physiological parameter but by a set of the methods presented in this work.

Kit-stem cell factor (kit ligand) axis in GIST patients treated with imatinib

10046

Background: Gastrointestinal stromal tumors (GISTs) represent the majority of GI mesenchymal neoplasms. Imatinib (Gleevec; STI571; Novartis, Basel, Switzerland) has marked efficacy in the management of GIST; however, little is known of its exact mechanism in GIST. We sought to elucidate expression patterns of stem cell factor (SCF, Kit ligand) and the Kit receptor tyrosine kinase in GIST and tumor-associated endothelial cells (TECs) from patients treated with imatinib. Methods: We constructed a 54 GIST specimen tissue array from patients with GIST surgically resected who received 400–800 mg/day adjuvant imatinib. Arrays were stained for SCF by immunohistochemistry and scored for expression as 0 (none), 1 (weak), or 2 (strong). Expression was correlated to progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier methods. In a second study we collected pre-imatinib core needle biopsies from 15 patients on a phase II prospective, randomized clinical trial of neo-adjuvant and adjuvant imatinib (600mg/day) for the treatment of primary or advanced, resectable GIST. Specimens were stained for phosphorylated-Kit and CD31 and visualized by immunofluorescence and confocal microscopy. Co-localization of markers was correlated to radiographic response by positron emission tomography (PET) and dynamic computed tomography (dCT). Results: 47 of 54 tumors (87%) expressed SCF but there was no significant correlation between SCF expression or intensity with PFS and OS. Interestingly, the majority of GIST tissue from patients on the prospective clinical trial contained pre-imatinib TECs expressing phosphorylated-Kit. 69% and 79% of patients receiving 3–7 days of imatinib responded by PET scan or dCT, respectively. Conclusions: The majority of GISTs express SCF while pre-imatinib TECs were found to express phosphorylated-Kit. Therefore, our results suggest that within the tumor microenvironment there may be Kit/SCF crosstalk between tumor cells and TECs. Whether disruption of this crosstalk plays a role in tumor response or anti-vascular efficacy requires additional investigation.

No significant financial relationships to disclose.

The clinical role of genetic polymorphisms in drug-metabolizing enzymes

For most drug-metabolizing enzymes (DMEs), the functional consequences of genetic polymorphisms have been examined. Variants leading to reduced or increased enzymatic activity as compared to the wild-type alleles have been identified. This review tries to define potential fields in the therapy of major medical conditions where genotyping (or phenotyping) of genetically polymorphic DMEs might be beneficial for drug safety or therapeutic outcome. The possible application of genotyping is discussed for depression, cardiovascular diseases and thromboembolic disorders, gastric ulcer, malignant diseases and tuberculosis. Some drugs used for relief of these ailments are metabolized with participation of genetically polymorphic DMEs including CYP2D6, CYP2C9, CYP2C19, thiopurine-S-methyltransferase, dihydropyrimidine dehydrogenase, uridine diphosphate glucuronosyltransferase and N-acetyltransferase type 2. Current evidence suggests that taking genetically determined metabolic capacities of DMEs into account has the potential to improve individual risk/benefit relationship. However, more prospective studies with clinical endpoints are needed before the paradigm of 'personalized medicine' based on DME variants can be established.