Fire ignition patterns to manage prescribed fire behavior: Application to Mediterranean pine forests

Climate change and the accumulation of surface fuel are leading to global changes in the occurrence of increasingly severe fires. In light of current budgetary constraints, prescribed fire can be a very cost-efficient tool for both reducing wildfire hazards and managing fire-prone landscapes. However, despite its widespread use in some countries, social and administrative constraints arise when applied at the European or larger scales. Science-based knowledge concerning fire behavior, fuel load reduction, and tree impacts is required to support the use of prescribed fire. Spatial ignition patterns can increase or decrease the spread rate, flame length, and flame residence time according to the objectives of a prescribed fire. This work aims to analyze fire behavior using different fire ignition patterns (strip-heading fire, flanking fire, and spot-heading fire) and meteorological and fuel conditions. Seventy-seven observations or sampling units using twenty-three prescribed fires were established for fire monitoring. Non-linear models based on environmental variables were fitted for the spread rate and flame length. Our study proposes a novel way of sharing scientific knowledge in relation to the most common distances between ignition lines and ignition points used in the southern Iberian Peninsula. The spread rate and flame length can be increased in strip-heading fire, by more than 3.5-fold and more than 1.95-fold, respectively, by modifying only the distance between ignition lines. Flanking fire could lead to a decrease in the spread rate by approximately half. Although spot-heading fire can reduce the spread rate by more than 78% and flame length by more than 41%, the highest distances between points could increase the flame residence time by 39-132%. This research seeks to achieve a trade-off between fire intensity and the impacts of fire on trees, soil, and surface roots.

The role of flagship species in the economic valuation of wildfire impacts: An application to two Mediterranean protected areas

Disturbance events play an important role in ecosystem services management and species biodiversity. In this sense, species biodiversity may constitute a large proportion of the total ecosystem value, mainly in natural protected areas. The present research proposes a methodology for the economic valuation of flagship species; the value of charismatic species was estimated using two complementary approaches based on recovery programs and contingent valuation method (CVM). While recovery programs approach is related to government expenditure, CVM is associated with survey results according to the society's willingness to pay. There are significant differences between both approaches as flagship species are highly valued by the society. In this sense, a difference of 43.75% on the species value can be found depending on the scenario of CVM (all respondents or only affirmative respondents). Our research was done on the integration of economic tools and wildfire severity of two burned areas in order to evaluate the effects caused in their habitat and, as a consequence, in the food chain. The results obtained from both the studied areas emphasized the importance of wildfire impacts on flagship species (209,619.08-445,495.88 € from Doñana wildfire and 634.68-5792.98 € from Segura wildfire) which are often omitted in valuation reports. The use of Geographic Information Systems helps to identify flagship species impacts per unit area (74.89-159.17 €/ha from Doñana wildfire and 0.76-6.98 €/ha from Segura wildfire) and to prioritize restoration activities on the most susceptible areas. This methodology could be extrapolated to any territory and spatial resolution based on the revision of the questionnaires regarding flagship species. The availability of cartography of flagship species´ susceptibility could play a critical role in budget optimization and the decision-making process on restoration planning.

Use of archival versus newly collected tumor samples for assessing PD-L1 expression and overall survival: an updated analysis of KEYNOTE-010 trial

BACKGROUND

In KEYNOTE-010, pembrolizumab versus docetaxel improved overall survival (OS) in patients with programmed death-1 protein (PD)-L1-positive advanced non-small-cell lung cancer (NSCLC). A prespecified exploratory analysis compared outcomes in patients based on PD-L1 expression in archival versus newly collected tumor samples using recently updated survival data.

PATIENTS AND METHODS

PD-L1 was assessed centrally by immunohistochemistry (22C3 antibody) in archival or newly collected tumor samples. Patients received pembrolizumab 2 or 10 mg/kg Q3W or docetaxel 75 mg/m2 Q3W for 24 months or until progression/intolerable toxicity/other reason. Response was assessed by RECIST v1.1 every 9 weeks, survival every 2 months. Primary end points were OS and progression-free survival (PFS) in tumor proportion score (TPS) ≥50% and ≥1%; pembrolizumab doses were pooled in this analysis.

RESULTS

At date cut-off of 24 March 2017, median follow-up was 31 months (range 23-41) representing 18 additional months of follow-up from the primary analysis. Pembrolizumab versus docetaxel continued to improve OS in patients with previously treated, PD-L1-expressing advanced NSCLC; hazard ratio (HR) was 0.66 [95% confidence interval (CI): 0.57, 0.77]. Of 1033 patients analyzed, 455(44%) were enrolled based on archival samples and 578 (56%) on newly collected tumor samples. Approximately 40% of archival samples and 45% of newly collected tumor samples were PD-L1 TPS ≥50%. For TPS ≥50%, the OS HRs were 0.64 (95% CI: 0.45, 0.91) and 0.40 (95% CI: 0.28, 0.56) for archival and newly collected samples, respectively. In patients with TPS ≥1%, OS HRs were 0.74 (95% CI: 0.59, 0.93) and 0.59 (95% CI: 0.48, 0.73) for archival and newly collected samples, respectively. In TPS ≥50%, PFS HRs were similar across archival [0.63 (95% CI: 0.45, 0.89)] and newly collected samples [0.53 (95% CI: 0.38, 0.72)]. In patients with TPS ≥1%, PFS HRs were similar across archival [0.82 (95% CI: 0.66, 1.02)] and newly collected samples [0.83 (95% CI: 0.68, 1.02)].

CONCLUSION

Pembrolizumab continued to improve OS over docetaxel in intention to treat population and in subsets of patients with newly collected and archival samples.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01905657.

Mitochondrial oligomers boost glycolysis in cancer stem cells to facilitate blebbishield-mediated transformation after apoptosis

Apoptosis culminates in secondary necrosis due to lack of ATP. Cancer stem cells form spheres after apoptosis by evoking the blebbishield emergency program. Hence, determining how blebbishields avoid secondary necrosis is crucial. Here we demonstrate that N-Myc and VEGFR2 control transformation from blebbishields, during which oligomers of K-Ras, p27, BAD, Bax, and Bak boost glycolysis to avoid secondary necrosis. Non-apoptotic cancer cells also utilize oligomers to boost glycolysis, which differentiates the glycolytic function of oligomers from their apoptotic action. Smac mimetic in combination with TNF-α or TRAIL but not in combination with FasL abrogates transformation from blebbishields by inducing secondary necrosis. Thus blebbishield-mediated transformation is dependent on glycolysis, and Smac mimetics represent potential candidates to abrogate the blebbishield emergency program.

DNA damage-induced ephrin-B2 reverse signaling promotes chemoresistance and drives EMT in colorectal carcinoma harboring mutant p53

Mutation in the TP53 gene positively correlates with increased incidence of chemoresistance in different cancers. In this study, we investigated the mechanism of chemoresistance and epithelial-to-mesenchymal transition (EMT) in colorectal cancer involving the gain-of-function (GOF) mutant p53/ephrin-B2 signaling axis. Bioinformatic analysis of the NCI-60 data set and subsequent hub prediction identified EFNB2 as a possible GOF mutant p53 target gene, responsible for chemoresistance. We show that the mutant p53-NF-Y complex transcriptionally upregulates EFNB2 expression in response to DNA damage. Moreover, the acetylated form of mutant p53 protein is recruited on the EFNB2 promoter and positively regulates its expression in conjunction with coactivator p300. In vitro cell line and in vivo nude mice data show that EFNB2 silencing restores chemosensitivity in mutant p53-harboring tumors. In addition, we observed high expression of EFNB2 in patients having neoadjuvant non-responder colorectal carcinoma compared with those having responder version of the disease. In the course of deciphering the drug resistance mechanism, we also show that ephrin-B2 reverse signaling induces ABCG2 expression after drug treatment that involves JNK-c-Jun signaling in mutant p53 cells. Moreover, 5-fluorouracil-induced ephrin-B2 reverse signaling promotes tumorigenesis through the Src-ERK pathway, and drives EMT via the Src-FAK pathway. We thus conclude that targeting ephrin-B2 might enhance the therapeutic potential of DNA-damaging chemotherapeutic agents in mutant p53-bearing human tumors.

Restoration of miR-101 suppresses lung tumorigenesis through inhibition of DNMT3a-dependent DNA methylation

The deregulation of miR-101 and DNMT3a has been implicated in the pathogenesis of multiple tumor types, but whether and how miR-101 silencing and DNMT3a overexpression contribute to lung tumorigenesis remain elusive. Here we show that miR-101 downregulation associates with DNMT3a overexpression in lung cancer cell lines and patient tissues. Ectopic miR-101 expression remarkably abrogated the DNMT3a 3′-UTR luciferase activity corresponding to the miR-101 binding site and caused an attenuated expression of endogenous DNMT3a, which led to a reduction of global DNA methylation and the re-expression of tumor suppressor CDH1 via its promoter DNA hypomethylation. Functionally, restoration of miR-101 expression suppressed lung cancer cell clonability and migration, which recapitulated the DNMT3a knockdown effects. Interestingly, miR-101 synergized with decitabine to downregulate DNMT3a and to reduce DNA methylation. Importantly, ectopic miR-101 expression was sufficient to trigger in vivo lung tumor regression and the blockage of metastasis. Consistent with these phenotypes, examination of xenograft tumors disclosed an increase of miR-101, a decrease of DNMT3a and the subsequent DNA demethylation. These findings support that the loss or suppression of miR-101 function accelerates lung tumorigenesis through DNMT3a-dependent DNA methylation, and suggest that miR-101-DNMT3a axis may have therapeutic value in treating refractory lung cancer.

Abstract P3-06-06: Lactate dehydrogenase B in breast cancer contributes to glycolytic phenotype and predicts response to neoadjuvant chemotherapy

Purpose: Although breast cancers are known to be molecularly heterogeneous, their metabolic heterogeneity is less well understood. This study aimed to identify and evaluate metabolic biomarkers in breast cancers and determine their ability to predict outcomes.

Methods: mRNA microarray data from breast cancer cell lines were used to identify bimodal genes, those with the highest potential for robust high/low classification in a clinical setting. Using a panel of breast cancer cell lines, expression and activity of the highest scoring bimodal metabolism gene, lactate dehydrogenase B (LDHB), was quantified and associated with glycolytic phenotype. The contribution of LDHB to glycolysis was evaluated using MDA-MB-231 and HCC1937 cell lines with stable lentiviral knockdown of LDHB. mRNA expression of LDHB was evaluated for association with neoadjuvant chemotherapy response within clinical and PAM50-derived subtypes.

Results: LDHB was highly expressed in cell lines with glycolytic, basal-like phenotypes. Knockdown of LDHB in cell lines reduced glycolytic dependence, linking LDHB expression directly to metabolic function. Using four independent patient datasets, LDHB mRNA expression was positively associated with basal subtype and negatively associated with luminal and HER2 subtypes. Furthermore, LDHB predicted basal phenotype independently of hormone-receptor (HR) clinical status (OR = 21.6 for HR-positive/HER2-negative and OR = 18.2 for triple-negative). While LDHB expression could predict basal phenotype, high LDHB expression identified aggressive breast cancer tumors that were primarily but not exclusively basal. Importantly, high LDHB expression predicted pathological complete response to neoadjuvant chemotherapy for both hormone receptor (HR) positive/HER2-negative (OR = 4.0, P = .0002) and triple-negative (OR = 3.0, P = .003) cancers. Consistent with increased response to chemotherapy, LDHB expression in basal cancers within the triple-negative group was associated with the proliferative marker CCNB1 (P < .0001).

Conclusion: mRNA expression of LDHB as a single marker predicted glycolytic phenotype in cell lines and response to neoadjuvant chemotherapy in breast cancers independently of HR status. These observations support prospective clinical evaluation of LDHB as a predictive marker of response for breast cancer patients treated with neoadjuvant chemotherapy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-06.

Prophylactic cranial irradiation in small-cell lung cancer: findings from a North Central Cancer Treatment Group Pooled Analysis

BACKGROUND

This pooled analysis evaluated the outcomes of prophylactic cranial irradiation (PCI) in 739 small-cell lung cancer (SCLC patients with stable disease (SD) or better following chemotherapy ± thoracic radiation therapy (TRT) to examine the potential advantage of PCI in a wider spectrum of patients than generally participate in PCI trials.

PATIENTS AND METHODS

Three hundred eighteen patients with extensive SCLC (ESCLC) and 421 patients with limited SCLC (LSCLC) participated in four phase II or III trials. Four hundred fifty-nine patients received PCI (30 Gy/15 or 25 Gy/10) and 280 did not. Survival and adverse events (AEs) were compared.

RESULTS

PCI patients survived significantly longer than non-PCI patients {hazard ratio [HR] = 0.61 [95% confidence interval (CI): 0.52-0.72]; P < 0.0001}. The 1- and 3-year survival rates were 56% and 18% for PCI patients versus 32% and 5% for non-PCI patients. PCI was still significant after adjusting for age, performance status, gender, stage, complete response, and number of metastatic sites (HR = 0.82, P = 0.04). PCI patients had significantly more grade 3+ AEs (64%) compared with non-PCI patients (50%) (P = 0.0004). AEs associated with PCI included alopecia and lethargy. Dose fractionation could be compared only for LSCLC patients and 25 Gy/10 was associated with significantly better survival compared with 30 Gy/15 (HR = 0.67, P = 0.018).

CONCLUSIONS

PCI was associated with a significant survival benefit for both ESCLC and LSCLC patients who had SD or a better response to chemotherapy ± TRT. Dose fractionation appears important. PCI was associated with an increase in overall and specific grade 3+ AE rates.

PTEN, NHERF1 and PHLPP form a tumor suppressor network that is disabled in glioblastoma

The PI3K-Akt pathway is activated in cancer by genetic or epigenetic events and efforts are under way to develop targeted therapies. PTEN tumor suppressor is the major brake of the pathway and a common target for inactivation in glioblastoma, one of the most aggressive and therapy-resistant cancers. To achieve potent inhibition of the PI3K-Akt pathway in glioblastoma, we need to understand its mechanism of activation by investigating the interplay between its regulators. We show here that PTEN modulates the PI3K-Akt pathway in glioblastoma within a tumor suppressor network that includes NHERF1 and PHLPP1. The NHERF1 adaptor, previously characterized by our group as a PTEN ligand and regulator, shows also PTEN-independent Akt-modulating effects that led us to identify the PHLPP1/PHLPP2 Akt phosphatases as NHERF1 ligands. NHERF1 interacts via its PDZ domains with PHLPP1/PHLPP2 and scaffolds heterotrimeric complexes with PTEN. Functionally, PHLPP1 requires NHERF1 for membrane localization and growth suppressive effects. PHLPP1 loss boosts Akt phosphorylation only in PTEN-negative cells and cooperates with PTEN loss for tumor growth. In a panel of low-grade and high-grade glioma patient samples, we show for the first time a significant disruption of all three members of the PTEN-NHERF1-PHLPP1 tumor suppressor network in high-grade tumors, correlating with Akt activation and patients’ abysmal survival. We thus propose a PTEN-NHERF1-PHLPP PI3K-Akt pathway inhibitory network that relies on molecular interactions and can undergo parallel synergistic hits in glioblastoma.

Clinical benefits TH-302, a tumor-selective, hypoxia-activated prodrug, and gemcitabine in first-line pancreatic cancer (PanC)

265

Background: Gemcitabine (G) is the standard treatment for first- line PanC. PanC is one of the most hypoxic solid tumors. TH-302 is an inert prodrug of brominated isophosphoramide mustard and undergoes selective activation in deep hypoxia. As a single agent, tumor responses were reported in patients (pts) with metastatic melanoma, SCLC, and head/neck cancer at TH-302 weekly doses of 480-575 mg/m2.

Methods: Eligible pts for the PanC expansion of this phase I/II study ( NCT00743379 ) had ECOG <1, locally advanced or metastatic PanC previously untreated with systemic chemotherapy other than adjuvant G, 5FU, and/or radiation. IV TH-302 was dosed at 240-575 mg/m2 (240 or 340 in expansion) with standard dose G (1000 mg/m2) on days 1, 8 and 15 of a 28-day cycle. Serum protein and microRNA hypoxia biomarkers were analyzed at baseline, start of cycle 3 and end of study.

Results: 46 PanC subjects (12 locally advanced, 34 distant mets); median age: 63 (range 41-83); 24 male; ECOG 0/1 in 29/17 pts; RECIST response rate (RR) of 21%, median PFS of 6.1 mo (95%CI 4.8, 7.7) and median survival of 11.4 mo (95%CI 6.0, not reached) were observed. RR was 23% with median survival of 7.4 mo in pts with distant mets. 52% of pts had a >50% decrease in CA19-9. Common adverse events were skin or mucosal toxicity, nausea, fatigue and vomiting; most grade 1/2. Grade 3/4 neutropenia, thrombocytopenia and anemia in 68%, 64%, and 20% of pts respectively. The dose intensities at 240 mg/m2 and 340 mg/m2 were similar and related to hematologic toxicities. Skin toxicities were less common at 240 mg/m2. A TH-302 dose response was present with higher RR and PFS at 340 mg/m2. Initial serum hypoxia biomarkers did not identify a preferential pt population.

Conclusions: The activity and clinical benefits of the combination of TH-302 with G in first line PanC are promising as compared to previous studies of G alone. TH-302 adds to the hematologic toxicity of G, but the regimen is well tolerated. The safety and activity provided rationale for comparing TH-302 plus G versus G alone in a randomized phase II trial ( NCT01144455 ) and indicate TH-302 may complement G by penetrating into the hypoxic regions of the PanC tumors where activation induces cytotoxicity.

No significant financial relationships to disclose.

Phase II trial of pazopanib in progressive, metastatic, iodine-insensitive differentiated thyroid cancers

3521

Background: Systemic therapies have had little impact on the outcomes of patients with advanced differentiated thyroid cancers. Methods: A three-outcome one-stage Phase II trial was conducted to assess the anti-tumor activity and toxicities of the orally bioavailable VEGF/tyrosine kinase inhibitor pazopanib (800 mg daily) in patients with advanced and progressive radioiodine-insensitive differentiated thyroid cancers. Up to 2 prior therapies were allowed, with measurable disease required. Design: at the 0.10 significance level, there would be a 90% chance of detecting a RECIST response rate of >20% given a true response rate of >5%; with the regimen considered promising if >4 confirmed responses observed. Results: From February to November 2008, 32 patients (53% male) aged 23–79 years (median: 63 years) were enrolled. Common sites of metastases were: lung (100%), nodes (52%), and bone (39%). Measurement data are available for 26 patients, with the median number of cycles administered thus far 4 (range: 1–8, total: 101). Overall, therapy has been well tolerated. Six patients (23%) required dose reduction due to: grade 2+ ALT (3 pts), grade 3 mucositis (1 pt); grade 3 diarrhea and dehydration (1 pt), and grade 3 abdominal pain (1 pt.). Other serious toxicities included grade 3 colon perforation and grade 3 chest pain (1 pt). No thyroglobulin antibody (TGA) negative patient has become TGA positive, and 11 of 16 patients (69%) with initially elevated thyroglobulin levels experienced a decline in thyroglobulin of >50%. Five RECIST partial responses have been confirmed to date (19%). Two patients are alive with disease progression and another has died from disease progression. Conclusions: Pazopanib appears to have both a favorable toxicity profile and promising clinical activity in patients with advanced and progressive differentiated thyroid cancers. Supported in part by NCI CA15083 and CM62205.

No significant financial relationships to disclose.

Comparison of progression-free survival (PFS) and tumor response as endpoints for predicting overall survival (OS) in untreated extensive-stage small cell lung cancer (ED-SCLC): Findings based on North Central Cancer Treatment Group (NCCTG) trials

8085

Background: Historically, tumor response has been the primary endpoint in phase II (P2) trials in ED-SCLC. We investigated the suitability of alternate PFS based endpoints to predict OS as early evidence of efficacy in the P2 setting. Methods: Individual patient (pt) data from 942 pts from 11 previously untreated ED-SCLC P2 and phase III (P3) platinum- or paclitaxel-based treatment trials were pooled. Best response (BR), response confirmed (RC), objective status at 16 weeks (RR16), and PFS rate at 5 and 6 months were considered. Percent agreement (PA) and kappa (k) for PFS5, PFS6, BR, RC, and RR16 with OS at 12 months (OS12) was calculated on a per-pt basis and predictive utility was assessed using the area under the receiver operating characteristic (A- ROC) curve in logistic models. Cox models were used to assess the prognostic impact of the endpoints on subsequent survival, using landmark analysis. Results: The median OS and PFS were 9.6 m and 5.5 m, respectively. PFS5 and PFS6 had the highest PA, k, and A-ROC values, and were predictive of subsequent survival in the landmark analysis (p <0.0001; c-statistics ≥ 0.60). While RR16 and BR were significantly associated with subsequent survival (p<0.0001, c-statistics of 0.61 and 0.57, respectively) the PA, k, and A-ROC values were lower. Conclusions: PFS rate at 5 and 6 months is more predictive of 12-month OS and subsequent survival than tumor response in untreated ED-SCLC. PFS based endpoints should be routinely used as primary endpoints in P2 trials within ED-SCLC.

[Table: see text]

No significant financial relationships to disclose.

A phase I study of lapatinib and topotecan in patients with solid tumors

3598

Background: Drug resistance to topotecan can be the result of BCRP/ABCG2 expression. BCRP is a member of the ABC transporter family that pumps anticancer drugs out of the cell. Lapatinib is a potent and selective dual inhibitor of epidermal growth factor receptor (EGFR or ErbB1) and ErbB2 (Her2/Neu). 4-aminoquinazoline tyrosine kinase inhibitors have been shown to enhance the cytotoxicity of topotecan through inhibition of BCRP-mediated drug efflux in cancer cells. Methods: Thirty-seven patients with advanced stage cancers were enrolled at escalating dose levels of lapatinib and topotecan in cohorts IA, IB and IIB (MTD). Treatment schedule included lapatinib (750 - 1500 mg/d) daily for 21 (cohort IA) or 28 days (cohort IB) and topotecan (2.4 - 4.0 mg/ m2), days 1, 8 and 15; cycles were repeated every 28 days. Three patients were treated at each dose level, 18 on cohort IA, 9 on cohort IB and 10 at MTD (cohort IIB). Assessments of toxicity were performed with each cycle and clinical response was determined per RECIST criteria every other cycle. Results: The MTD for cohorts IA and IB was reached at a dose of 1250 mg of lapatinib and 3.2 mg/m2 of IV topotecan on days 1, 8 and 15. No DLT were seen during the dose escalation stage of cohorts IA and IB. Ten patients were enrolled at the MTD. There were no grade 4+ events. Thirteen grade 3+ events, considered to be related to treatment, were seen in 6 patients. The most common grade 3+ toxicities included dehydration (2) diarrhea (2), nausea (3), vomiting (2), neutropenia (1), thrombocytopenia (1), and fatigue (1). No abnormalities in left ventricular ejection fraction were noted. Stable disease was seen in 46% of the 37 patients. Conclusions: The combination of lapatinib and topotecan is a well-tolerated regimen. The MTD for the combination is lapatinib 1,250 mg orally once daily for 21 or 28 days and topotecan 3.2 mg/m2 on days 1, 8 and 15. Pharmacokinetic analysis for drug interaction will be available for presentation at the meeting. Supported in part by GSK and Mayo Clinic

No significant financial relationships to disclose.

A phase I study with exploratory pharmacodynamic endpoints of XL647, a novel spectrum selective kinase inhibitor, administered orally daily to patients (pts) with advanced solid malignancies

14044

Background: XL647 is an orally bioavailable small molecule inhibitor of multiple receptor tyrosine kinases involved in tumorigenesis, angiogenesis, and metastasis, including EGFR/ErbB1, ErbB2/HER2, VEGFR2/KDR, and EphB4. In a previous Phase I study, the MTD was 350 mg when XL647 was dosed orally for 5 consecutive days every 14 days. Of 41 pts treated, one pt with NSCLC achieved a PR and 14 pts had prolonged stable disease (3.5–14+ months). The purpose of the present study is to determine the MTD of XL647 administered orally on a continuous daily schedule. Methods: Pts are enrolled in successive cohorts to receive XL647 daily for repeated 28 day cycles. PK sampling is performed to determine Cmax, and AUC at each dose level. Plasma samples are analyzed by ELISA for mechanism-of-action related molecules. Eyebrow hair bulbs are being evaluated by IHC to monitor effects of XL647 on signal transduction pathways downstream of EGFR. Tumor response is assessed every 8 weeks by RECIST. Pts remain on study until PD or unacceptable AEs. Results: Twelve pts have been enrolled. The starting dose was 75 mg (n=3) and has been escalated to150 mg (n=3), 200 mg (n=3) and 300 mg (n=3). To date, dose escalation continues as no DLTs have occurred and the MTD has not been determined. Ten pts remain on study, including 4 with stable disease for at least 3 months. In cohort 2, eyebrow samples from 3 pts were analyzed. XL647 caused a significant reduction in the phosphorylation of the EGFR downstream signaling kinases AKT (up to 73%) and ERK (up to 78%) in 2/3 and 3/3 pts, respectively. Preliminary analysis of potential plasma protein biomarkers from pts in cohorts 1 and 2 showed a trend towards upregulation of PlGF plasma levels in 4/6 pts during XL647 treatment. Conclusions: XL647 is well-tolerated when administered daily at doses tested to date. Dose escalation will continue until the MTD is defined. Analysis of eyebrow samples demonstrated its feasibility as a potential surrogate epidermal tissue for assessing inhibition of EGFR downstream targets by XL647. Updated safety, PK and pharmacodynamic results will be presented.

[Table: see text]

A front-line window of opportunity phase II study of sorafenib in patients with advanced non-small cell lung cancer: A North Central Cancer Treatment Group study

7547

Background: Sorafenib is a multikinase inhibitor with single-agent activity in previously treated NSCLC. In an effort to evaluate its single agent activity in previously untreated NSCLC, the NCCTG undertook a front-line “window of opportunity” study. Materials and Methods: Patients with stage IIIB (pleural effusion) or stage IV NSCLC received sorafenib dosed at 400 mg BID continuously, with a cycle defined as 4 weeks. Patients were evaluated weekly during the first 2 cycles with those who progressed rapidly going on to receive standard chemotherapy. Based on a two-stage Fleming design, if only at most 1 confirmed response was observed in the first 20 patients enrolled to stage I, the regimen would be considered ineffective. If 2 or more responses were observed, the study would proceed to stage 2 and accrue an additional 22 patients. If 5 or more confirmed responses were observed, the regimen would be recommended for further testing. Results: The study did not meet the stage I efficacy criteria (only 1 confirmed partial response in the first 20 patients) and was permanently closed after enrolling 25 evaluable patients [15 females, 10 males; 4 stage IIIB, 21 stage IV; median age 67 (45–85)]. 2 patients are still receiving treatment (14 and 15 months). No grade 3 or higher hematologic adverse events were observed. Thirteen (52%) patients had a grade 3 non-hematologic adverse event with fatigue (20%), diarrhea (8%), and dyspnea (8%) being the most common. There was one grade 4 pulmonary hemorrhage. A total of 3 (12%) PRs; and 7 (28%) SD were observed in the 25 patients 7 (28%) patients were progression- free at 24 weeks. Median survival and median time to progression were 8.8 and 2.9 months respectively. Conclusion: While the pre- specified efficacy endpoints were not met, the objective response rate of 12% and median survival of 8.8 months suggest that single agent sorafenib has activity similar to two-drug combinations. The feasibility and utility of the “window of opportunity” design in estimating the activity of novel compounds was demonstrated. Finally, the single-agent activity of sorafenib argues for combination studies with standard chemotherapy agents.

No significant financial relationships to disclose.

Reticulocyte Maturation Parameters Are Reliable Early Predictors of Hematopoietic Engraftment after Allogeneic Stem Cell Transplantation

Early detection of donor-derived hematopoietic restoration after allogeneic stem cell transplantation (allo-SCT) is a crucial issue in the management of heavily immunocompromised patients. The aim of this prospective study was to validate our previously defined cutoff values for reticulocyte maturation parameters as early predictors of hematopoietic engraftment. Importantly, the effect of clinical variables in reticulocyte engraftment was also sought. For this purpose, we prospectively studied 136 consecutive patients undergoing allo-SCT from related (n = 89) or unrelated (n = 47) donors. High fluorescence reticulocytes (RETH), immature reticulocyte fraction (IRF), mean fluorescence index (MFI), and mean reticulocyte volume (MRV) were automatically measured in peripheral blood samples drawn on a daily basis. We previously defined reticulocyte engraftment when MFI > or =10, RETH > or =3%, IRF > or =10%, and MRV > or =110 fL. Median neutrophil engraftment was 18 days (range, 10-35 days); for reticulocyte parameters, the values were 14 days for IRF (range, 7-45 days), 14 days for MFI (range, 7-43 days), 15 days for RETH (range, 7-43 days), and 21 days for MRV (range, 9-74 days). These differences reached statistical significance for MFI and IRF when compared with standard neutrophil recovery, even when analyzing siblings or unrelated donors separately. In univariate analysis, donor-recipient ABO disparity adversely influenced erythroid engraftment (P = .04 for IRF, P = .03 for MFI), but the infusion of >2.9 x 10(6)/kg of CD34+ cells was associated with a shorter time to reach erythroid engraftment (P = .02 for IRF and MFI). In Cox regression analysis, > or =100/microL neutrophils and IRF > or =10% were predictive parameters for standard neutrophil engraftment. Based on these findings, we suggest that serial measurement of IRF or MFI should be routinely used to trace hematopoietic restoration after allo-SCT because these preceded standard neutrophil recovery by a median of 4 days and are therefore very useful to make clinical decisions.

Study design considerations in clinical outcome research of lung cancer using microarray analysis

BACKGROUND

Prognosis following a diagnosis of primary lung cancer is very poor and varies significantly even after adjusting for known predictors. Inherent and acquired gene alterations could cause failure in lung cancer treatment and patient survival. To search for potential molecular markers with significant and independent predictive value in lung cancer survival, we applied oligo-nucleotide microarray analysis, along with patients' phenotypic profile, in a case-control study. The focus of this report is on the methodology used in the identification of potential genes as prognostic factors.

METHODS

Selected from 304 patients at Mayo Clinic, 18 stage I squamous cell lung cancer patients who died within 2 years (high-aggressive) or lived beyond 5 years (low-aggressive) were included in this study. Both a one-to-one matched design (paired) and a two-group design (grouped) were utilized. Matching variables were age, gender, tumor size and grade, smoking status, and treatment. Two-GeneChip-array sets from Affymetrix (HG-U133) were used. We applied multiple analytic approaches including Dchip (Harvard University), SAM (Stanford University), ArrayTools (US National Cancer Institute), and MAS5 (Affymetrix); and integrated multiple results to generate the final candidate genes for further investigation. We evaluated the consistency across the methods and the effects of matched versus grouped design on the results.

RESULTS

Using the same pre-processed data under the same criteria for type I error and fold-change in expression intensity, results are 94-100% concordant in the list of significant genes by Dchip and by ArrayTools, and 53% concordant between the paired and the grouped analysis. If using differently pre-processed data, the concordance rate is under 6% even by the same analytic tool. Combining results from all analyses, we found 23 potentially important genes that may distinguish the high- versus low-aggressive squamous cell tumors of the lung.

CONCLUSION

Given the generally low consistency of results across analytic algorithms and study design, poor agreement is expected from different investigators reporting candidate genes for the same endpoint. A well-designed study with a carefully planned analytic strategy is critical. We are in the process of validating the 23 preliminary candidate genes found from this study among independent yet comparable cases.

Secretion of dopamine and norepinephrine in hypophyseal portal blood and prolactin in peripheral blood of Holstein cattle

The objective was to test the hypothesis that dopamine regulates prolactin (PRL) secretion by determining acute changes in catecholamine concentrations in hypophyseal portal blood of cattle, and their relation to peripheral blood concentration of PRL in hypophyseal stalk-transected (HST) and sham-operated controls (SOC). Holstein heifers (606 +/- 21 kg BW; mean +/- SE) were subjected to neurosurgery for 8 h to collect hypophyseal portal blood with a stainless steel cannula designed with a cuff placed under the pituitary stalk and peripheral blood via a jugular vein catheter. PRL plasma concentration was measured by radioimmunoassay, and dopamine and norepinephrine in portal plasma by radioenzymatic assay. During anesthesia before HST or SOC, PRL plasma concentration ranged from 20-40 ng/ml throughout 255 min. PRL abruptly increased and remained above 90 ng/ml after HST compared with a steady decrease to <20 ng/ml in SOC heifers throughout 440 min. Within 5 min after severing the hypophyseal stalk, dopamine in portal blood (>8 ng/ml) was significantly increased (P < 0.05) compared with peripheral blood (<2 ng/ml). Norepinephrine concentration in portal blood was significantly greater (P < 0.05) than in peripheral blood during the first 60 min. The sustained high PRL level in peripheral plasma after severing the hypophyseal stalk stimulated hypothalamic dopamine secretion from hypophyseal portal vessels during the prolonged period of blood collection. Norepinephrine concentration in these cattle was greater in hypophyseal portal than in peripheral blood, implicating both an important hypothalamic source of the catecholamine as well as an adrenal gland contribution during anesthesia.

Effect of blood sampling and administration of ACTH on cortisol and progesterone levels in ovariectomized zebu cows (Bos indicus)

Four zebu cows were bilaterally ovariectomized through lateral laparotomy. Three months after ovariectomy, blood samples were collected by jugular venipuncture daily for 5 consecutive days prior to a single injection of ACTH to establish baseline concentrations of cortisol and progesterone. Baseline concentrations of cortisol and progesterone were 31 +/- 5 nmol/L and 0.3 +/- 0.01 nmol/L, respectively. On the day of ACTH treatment the cows were allowed to rest for 2 h to reduce the stress of cannulation before the sampling period started. Blood samples were collected every 30 min from 2 h before until 2 h after the injection of 6 micrograms ACTH and hourly between 2-6 h after ACTH injection. A significant increase was observed in cortisol secretion from 90 min before until 120 min after ACTH injection. No significant increase was observed in progesterone secretion before ACTH injection. After ACTH injection progesterone was significantly elevated for 120 min. Four weeks after the ACTH treatment the cows were cannulated again and blood samples were collected following the same bleeding schedule used during the ACTH experiment. Instead of ACTH a saline injection was given via the catheter. A significant increase in cortisol concentration was recorded 90 min before saline injection. This increase was not accompanied by an elevation in progesterone concentration. No significant changes were observed in cortisol and progesterone levels after saline injection. When cortisol was added to a plasma pool having a progesterone concentration of 0.3 nmol/L and a cortisol concentration of 25.4 nmol/L and assayed for progesterone in 2 different assays no increase in progesterone concentration was observed. We conclude that the adrenal glands can be an extra-ovarian source of progesterone during stress in Zebu cows.

Gastric lesions in transforming growth factor beta-1 heterozygous mice

Transforming growth factor beta-1 (TGF beta 1) is known to inhibit the growth of many epithelial cell types in culture. Consequently, it is important to determine whether it has any tumor suppressor activity in vitro. Fifteen heterozygous and eight wild type TGF beta 1-deficient mice were examined to determine if there was a difference in lifespan or lesion development due to the loss of one TGF beta 1 allele. Mice were killed when there was evidence of neoplasia or severe illness. There was no significant difference in the lifespan of the two groups. Hyperplastic lesions in the glandular mucosa were seen in 10 TGF beta 1 (+/-) mice. These lesions were localized to the lesser curvature of the stomach, extending from the limiting ridge to the pylorus. Seven of the 10 glandular hyperplastic lesions in the TGF beta 1 (+/-) mice had features similar to human gastritis cystica profunda. Associated with the glandular invasion of the muscularis were a mixed inflammatory infiltration of the surrounding muscular wall and mucosa with chronic vasculitis in the tissues adjacent to these lesions. In contrast to the distinct genotypic differences in lesion incidence observed in the glandular stomach, there was no significant difference in lesion incidence in other organs. The increased incidence of the hyperplastic lesions in the TGF beta 1 (+/-) mice is highly suggestive that allelic loss of TGF beta 1 plays an important role in the genesis of these lesions. However, allelic loss of TGF beta 1 does not cause alterations in the incidence of neoplasia.

Effects of calf removal at parturition on postpartum ovarian activity in Zebu (Bos indicus) cows in the humid tropics

To assess endocrine and morphological responses of ovaries to total weaning at parturition, 6 Zebu (Bos indicus) cows 5 years or older were investigated. Following parturition, blood samples were collected daily during the first month and twice weekly thereafter until day 60 to determine concentrations of progesterone (P4) and prostaglandin F2 alpha metabolite. It took between 25 to 32 days to complete uterine involution. The prostaglandin metabolite remained elevated for a mean period of 14.2 days (range, 4-21) postpartum. Five of the animals resumed cyclicity with a short estrous cycle starting between days 7 to 34 and lasting between 7 and 14 days. No estrous behavior was recorded prior to the short estrous cycles, but subsequent normal-length estrous cycles were all preceded by signs of estrus. In the 1 animal that resumed cyclicity with an estrous cycle of normal length on day 37 (length 20 days), the cycle was preceded by estrous behavior. Progesterone concentrations reached a mean maximum of 4.8 nmol liter-1 during the short estrous cycles, and prostaglandin metabolite concentrations peaked while P4 concentrations were decreasing. P4 concentrations reached a mean maximum of 12.2 nmol liter-1 during the estrous cycles of normal length. The interval from parturition to the first estrous cycle of normal length varied between 16 and 48 days, and the length of the cycle was 18 to 22 days. Starting 2 days postpartum, ovaries from 5 of the cows were scanned by ultrasonography every second day until day 30 postpartum. Medium-sized follicles were detected between days 4 to 7 postpartum in 4 of the scanned cows that later had short estrous cycles. The time between parturition and the appearance of the first dominant follicle was 7.6 days (range 6-10 days). The interval between parturition and the appearance of the first ovulatory-sized follicle was 10.2 days (range 8-13 days). In 3 of the scanned cows this ovulatory-sized follicle ovulated. We conclude that cyclic ovarian activity in Zebu cows can start early in the postpartum period in the absence of offspring, and that short luteal phases, not preceded by estrous behavior, may play an important role in establishing normal postpartum ovarian activity.

Composite and plain tubular synthetic graft conduits in right ventricle-pulmonary artery position: fate in growing lambs

Our goal was to identify the most appropriate material for right ventricle-pulmonary artery conduits in growing animals. We used 100 lambs that were 3 to 4 weeks old (mean weight 11.7 kg). Follow-up was up to 24 months. Group I received plain tubular conduits: (1) Dacron knitted fabric, (2) collagen-coated knitted fabric, (3) Milliknit and Microknit material, (4) woven Dacron fabric, (5) three-dimensional Dacron fabric (crossweave 500 and 800), or (6) polytetrafluoroethylene. Group II received either a (1) woven Dacron fabric conduit with a built-in tissue valve or (2) polytetrafluoroethylene graft with a built-in St. Jude Medical valve. We did angiograms and catheterizations every 3 to 6 months and killed the lambs at 6, 12, 18, or 24 months. Tubular Dacron fabric woven or knitted grafts, regardless of matrix, pore size, thickness, or coating, caused formation of a thick acellular pseudointima buildup, which led to progressive obstruction starting as early as 3 months. Polytetrafluoroethylene grafts in groups I and II showed the formation of thin inner and outer capsules (0.5 mm) and none developed obstruction despite wall calcification. Conduits of woven Dacron fabric with a built-in tissue valve degenerated rapidly, leading to calcification thrombosis and obstruction within 3 months; no lamb survived 12 months. Polytetrafluoroethylene conduits with a St. Jude Medical valve in lambs receiving anticoagulants remained free of obstruction and continued to function well. It appears that synthetic conduits of polytetrafluoroethylene perform well in either of the situations here tested and may be the best choice at present.

Effects of calf removal at parturition on postpartum ovarian activity in Zebu (Bos indicus) cows in the humid tropics

To assess endocrine and morphological responses of ovaries to total weaning at parturition, 6 Zebu (Bos indicus) cows 5 years or older were investigated. Following parturition, blood samples were collected daily during the first month and twice weekly thereafter until day 60 to determine concentrations of progesterone (P4) and prostaglandin F2 alpha metabolite. It took between 25 to 32 days to complete uterine involution. The prostaglandin metabolite remained elevated for a mean period of 14.2 days (range, 4-21) postpartum. Five of the animals resumed cyclicity with a short estrous cycle starting between days 7 to 34 and lasting between 7 and 14 days. No estrous behavior was recorded prior to the short estrous cycles, but subsequent normal-length estrous cycles were all preceded by signs of estrus. In the 1 animal that resumed cyclicity with an estrous cycle of normal length on day 37 (length 20 days), the cycle was preceded by estrous behavior. Progesterone concentrations reached a mean maximum of 4.8 nmol liter-1 during the short estrous cycles, and prostaglandin metabolite concentrations peaked while P4 concentrations were decreasing. P4 concentrations reached a mean maximum of 12.2 nmol liter-1 during the estrous cycles of normal length. The interval from parturition to the first estrous cycle of normal length varied between 16 and 48 days, and the length of the cycle was 18 to 22 days. Starting 2 days postpartum, ovaries from 5 of the cows were scanned by ultrasonography every second day until day 30 postpartum. Medium-sized follicles were detected between days 4 to 7 postpartum in 4 of the scanned cows that later had short estrous cycles. The time between parturition and the appearance of the first dominant follicle was 7.6 days (range 6-10 days). The interval between parturition and the appearance of the first ovulatory-sized follicle was 10.2 days (range 8-13 days). In 3 of the scanned cows this ovulatory-sized follicle ovulated. We conclude that cyclic ovarian activity in Zebu cows can start early in the postpartum period in the absence of offspring, and that short luteal phases, not preceded by estrous behavior, may play an important role in establishing normal postpartum ovarian activity.

Onset of spermatogenesis in Corriedale ram lambs under extensive rearing conditions in Uruguay

The present study was undertaken to estimate the time for the attainment of spermatogenesis in springborn Corriedale ram lambs under conditions of extensive grazing systems in Uruguay. Clinical (live weight, scrotal circumference, penile/preputial separation), morphological (light and electron microscopy) and endocrinological (testosterone levels) parameters were examined. Two experiments in 2 consecutive years were carried out. In Exp. I, 40 ram lambs were clinically examined, weighed, and blood-sampled at 2 week-intervals between 78 and 216 days of age. Sixteen were castrated in 3 selected periods: 132-162 (n:2), 145-175 (n:6) and 186-216 days (n:8). In Exp. II, 40 ram lambs appertaining to the next generation of the same flock were examined as above at 180-210 days of age, and castrated for morphological studies. The time for attainment of complete spermatogenesis correlated significantly with most corporal parameters (i.e. scrotal circumference (r = 0.52); testicular weight (r = 0.61), epididymal weight (r = 0.60), penile/preputial separation (r = 0.75). The age of castrated ram lambs correlated with the degree of spermatogenesis (r = 0.83), although no significant correlations were found with live weight or with levels of circulating testosterone. The histology showed major variations in the degree of development of the seminiferous epithelium. Cells undergoing degeneration were a common finding through the initial stages of spermatogenesis, coincident to the presence of sperm abnormalities and foreign cells in semen. By day 180 and onwards, both histology and seminal picture normalized. It is concluded that, under these rearing conditions, the onset of puberty (expressed as morphologically established spermatogenesis) in Corriedale ram lambs is attained at 180-216 days of age when they reach 23 cm of scrotal circumference and 191 g of testis weight. The finding of a high correlation between these parameters (r: 0.93) confirms the usefulness of the measurement of scrotal circumference during clinical examination of ram lambs in this breed.

Blood levels of the prostaglandin F2 alpha metabolite during the postpartum period in Bos indicus cows in the humid tropics

Plasma levels of the prostaglandin F2 alpha metabolite (15-ketodihydroprostaglandin F2 alpha) were determined by radioimmunoassay in 26 postpartum multiparous Brahman cows. Variation in the concentrations of the metabolite was high among animals. 15-Ketodihydro-PGF2 alpha concentrations on day 0, 5, 10, 15 and 20 postpartum ranged from 402 to > or = 1000, from 251 to > or = 1000, from 237 to > or = 1000, from 75 to 608 and from 75 to 267 pmol l-1, respectively. The prostaglandin metabolite levels were elevated at parturition and remained elevated thereafter for periods varying up to 10 to 23 days postpartum (16.7 +/- 0.7 days, mean +/- SEM). Uterine involution (UI) was completed by 28.0 +/- 0.8 days (ranging from 20 to 36 days). A markedly linear decrease of 15-ketodihydro-PGF2 alpha levels (P < 0.001) occurred from parturition until Day 23 postpartum. A significant correlation between the duration of the elevated PGF2 alpha metabolite and the time required for completion of UI was observed (r = -0.05, P < 0.01). The effect of parity (PT) on 15-ketodihydro-PGF2 alpha levels was not significant, however the relationship between UI and PT was affected (r = -0.59, P < 0.001). Both PGF2 alpha release and PT had effects on the variability of UI (R2 = 0.62, P < 0.001). No significant relationship was found between elevated levels of 15-ketodihydro-PGF2 alpha UI and PT with postpartum anoestrous interval (PPAI).

[Capture immunoassay for the detection of human IgG against Toxoplasma gondii protein P30]

Toxoplasmosis is a widely distributed disease with prevalence rates ranging between 40 and 80% in different parts of the world. The diagnosis of congenital toxoplasmosis constitutes a health problem since intra-uterine infection can lead to undesirable effects on the fetus. Immunoenzymatic methods are the techniques of choice for the serologic diagnosis of toxoplasmosis. The present paper describes an indirect sandwich ELISA with the murine anti-P30, the main surface antigen of Toxoplasma gondii, monoclonal antibody as the first antibody fixed to the polystyrene 96 wells plate for the capture of P30 molecule from T. gondii extracts and to detect the presence of human anti-P30 IgG. Serum samples from 42 pregnant women were studied and compared to results obtained with a commercial kit (Plastelia Toxo IgG, Institute Pasteur, Lille, France) for the same purpose, in which 83.4% of the serum samples were positives. Our results demonstrated a significant correlation (p < 0.001; r = 0.84) with those obtained with the commercial kit. We conclude that the IgG anti-P30 method should be very useful for screening of seroconversion in pregnant women not sensitized by T. gondii and to evaluate epidemiologically the prevalence rate infection by this parasite which can cause and transmit this disease subclinically.

Radioimmunoassay of bovine, ovine and porcine luteinizing hormone with a monoclonal antibody and a human tracer

A radioimmunoassay for bovine (bLH), ovine (oLH) and porcine (pLH) luteinizing hormone was developed using a human 125ILH tracer from a commercial kit and a monoclonal antibody (518B7) specific for LH but with low species specificity. Standard curves demonstrated similar binding kinetics when bLH, oLH and pLH were incubated with tracer and antibody for 2 h at room temperature. A 30-min delay in the addition of the tracer gave sufficient sensitivity when analysing pLH. Separation of antibody-bound LH from free hormone was achieved by using second antibody-coated micro Sepharose beads. The assay was validated and the performance compared with that of an RIA currently in use for determination of bLH and oLH (coefficient of correlation: 0.99 and 0.98). Regardless of the standards used, intra-assay coefficients of variation were < 10% for LH concentrations exceeding 1 microgram/L. The inter-assay coefficients of variation were < 15%. The assay was used for clinical evaluation demonstrating the pre-ovulatory LH surge in two cyclic cows, LH pulsatility in an oophorectomized ewe and LH response to GnRH injection in a boar.