Genetic analysis of single disseminated tumor cells in the lymph nodes and bone marrow of patients with head and neck squamous cell carcinoma

Considering the limited information on the biology and molecular characteristics of disseminated tumor cells (DTCs) in head and neck squamous cell carcinoma (HNSCC), we examined the genomic alterations in DTCs from HNSCCs and their potential clinical relevance. To analyze both the lymphatic and hematogenous routes of tumor cell dissemination, we investigated samples from lymph nodes (LNs) and bone marrow (BM) of 49 patients using immunofluorescence double staining for epithelial cells expressing cytokeratin 18 (KRT18) and/or epithelial cell adhesion molecules (EpCAM, CD326). The identified marker‐positive cells were isolated by micromanipulation followed by single‐cell whole‐genome amplification and metaphase‐based comparative genomic hybridization (mCGH) to determine genome‐wide copy number alterations. The findings were correlated with clinical parameters and follow‐up data. We detected chromosomal aberrations in KRT18‐ and EpCAM‐positive cells from both compartments; BM‐derived cells showed a significantly higher percentage of aberrant genome (PAG) per cell than cells detected in LNs. No significant association was found between DTC data and clinical follow‐up. Genomic profiling of BM‐DTCs revealed genomic alterations typical for HNSCC, suggesting hematogenous dissemination of subclones around the time of surgery. In contrast, DTC data in LNs revealed that several marker‐positive cells were not of malignant origin, indicating the presence of epithelial glandular inclusions in parts of the processed neck LN samples. Therefore, DTC detection of LNs in the neck based only on epithelial markers is not advisable and requires detection of chromosomal instability (CIN), gene mutations, or additional markers, which have yet to be identified. Nevertheless, our investigation paves the way for larger studies to focus on HNSCC BM‐DTCs with high‐resolution methods to gain deeper insights into the biology of hematogenous metastasis in this cancer.

Abstract 3919: Liquid biopsy derived organoids as a potential platform for personalized cancer therapy in metastatic prostate cancer

Introduction

Circulating tumor cells (CTCs) can serve as a source of metastatic tumor material, however their low numbers often limit downstream applications. Diagnostic leukapheresis (DLA) has been shown to substantially increase CTC yield. In this study we isolated CTCs from metastatic prostate cancer (mPCa) patients by DLA to propagate them in vitro as organoid cultures. Furthermore, tumor-derived organoids were used as a model for drug discovery and sensitivity-screening, thereby exploring potential treatment selection.

Methods

We included 44 mPCa patients into the study and 18 were selected for DLA, based on the presence of ≥5 CTCs/ 7.5 mL blood. We optimized the DLA procedure by comparing low versus high density settings and their impact on CTC isolation efficacy. As the DLA product contains a median of 8.6*10^9 white blood cells (WBC), stringent enrichment methods are needed. CTC enrichment from DLA product was performed by antibody-based WBC depletion alone, or combined with subsequent EpCAM based enrichment. Enriched CTC fractions were cultured in vitro under optimized conditions, to initiate organoid expansion.

Results

We show that DLA is a safe and efficient method to collect large amounts of CTCs from mPCa patients. With optimized DLA settings we were able to improve CTC enrichment and observed a non-significant increase in CTC yield from DLA (median CTC recovery 15339 vs 5796, P=0.125). WBC depletion alone was found to reduce WBCs by ~2000-fold while retaining >50% of the CTCs, resulting in a WBC to CTC ratio of 545:1. We were able to culture and confirm CTC-derived organoids in 9/18 samples, including one organoid cell line, EMC-PCa-41. Whole Genome Sequencing (WGS) of EMC-PCa-41 revealed a triploid genome characterized by focal amplification of AR, a TMPRSS2-ERG fusion, a PTEN deletion and multiple inter-chromosomal rearrangements. Next we determined copy number profiles in single CTCs and matched organoids from two patients using shallow WGS. These data confirm prior data that CTCs represent the inherent intra-patient heterogeneity and organoids resemble CTCs from the original DLA product. Moreover, we performed an in vitro drug screen with the organoid cell line EMC-PCa-41, and found that it has a limited response to Enzalutamide, which correlated with the relatively short response to Enzalutamide that was observed in the patient.

Conclusion

Overall our study demonstrates that DLA provides a high CTC yield which enables short-term organoid cultures that preserve the genomic hallmarks of prostate cancer. Viable CTCs obtained by DLA may serve as a (personalized) drug screening system in metastatic prostate cancer.

Citation Format: Lisanne Mout, Lisanne F. van Dessel, Jaco Kraan, Anouk C. de Jong, Rui P. Neves, Sigrun Erkens-Schulze, Anieta M. Siewerts, Job van Riet, Ronald de Wit, Stefan Sleijfer, Paul Hamberg, Yorick Sandberg, Peter A. te Boekhorst, Harmen J. van de Werken, John W. Martens, Nikolas H. Stoecklein, Wytske M. van Weerden, Martijn P. Lolkema. Liquid biopsy derived organoids as a potential platform for personalized cancer therapy in metastatic prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3919.

Detection of circulating tumor cells in colorectal cancer patients using the GILUPI CellCollector: results from a prospective, single-center study

The GILUPI CellCollector (CC) is a novel in vivo circulating tumor cell (CTC) detection device reported to overcome the limitations of small blood sample volumes. The aim of this prospective, blinded study was to evaluate the clinical application of the CC and to compare its performance to the CellSearch (CS) system in M0 and M1 colorectal cancer (CRC) patients. A total of 80 patients (31 M0, 49 M1) with CRC were enrolled. CTCs were simultaneously measured in the peripheral blood using CS and the CC, and the results of both assays were correlated to clinicopathological variables and overall survival. The total number of detected CTCs and CTC‐positive patients did not significantly differ between both assays. In the M0 patients, the CC detected CTCs more frequently than CS. There was no significant difference in total CTC numbers detected with the CC between M0 and M1 patients. In addition, no significant correlation with clinicopathological parameters or overall survival was observed with CC CTCs. In contrast, detection of CTCs with CS was significantly correlated with Union for International Cancer Control stage and reduced overall survival. There was no correlation between CTCs detected by the CC and the CS system. Using in silico analysis, we estimate that CC screens a volume of 0.33–18 mL during in vivo application, in contrast to much higher volumes reported elsewhere. In conclusion, while being safe and easy to use, the CC did not outperform CS in terms of CTC yield or sensitivity. While CTC detection in M0 CRC patients was significantly increased with the CC, the clinical relevance of these CTCs appears inferior to the cells identified by the CS system.

Single-Cell Analyses of Prostate Cancer Liquid Biopsies Acquired by Apheresis

Purpose: Circulating tumor cells (CTCs) have clinical relevance, but their study has been limited by their low frequency.Experimental Design: We evaluated liquid biopsies by apheresis to increase CTC yield from patients suffering from metastatic prostate cancer, allow precise gene copy-number calls, and study disease heterogeneity.Results: Apheresis was well tolerated and allowed the separation of large numbers of CTCs; the average CTC yield from 7.5 mL of peripheral blood was 167 CTCs, whereas the average CTC yield per apheresis (mean volume: 59.5 mL) was 12,546 CTCs. Purified single CTCs could be isolated from apheresis product by FACS sorting; copy-number aberration (CNA) profiles of 185 single CTCs from 14 patients revealed the genomic landscape of lethal prostate cancer and identified complex intrapatient, intercell, genomic heterogeneity missed on bulk biopsy analyses.Conclusions: Apheresis facilitated the capture of large numbers of CTCs noninvasively with minimal morbidity and allowed the deconvolution of intrapatient heterogeneity and clonal evolution. Clin Cancer Res; 24(22); 5635-44. ©2018 AACR.

Toward a real liquid biopsy in metastatic breast and prostate cancer: Diagnostic LeukApheresis increases CTC yields in a European prospective multicenter study (CTCTrap)

Frequently, the number of circulating tumor cells (CTC) isolated in 7.5 mL of blood is too small to reliably determine tumor heterogeneity and to be representative as a “liquid biopsy”. In the EU FP7 program CTCTrap, we aimed to validate and optimize the recently introduced Diagnostic LeukApheresis (DLA) to screen liters of blood. Here we present the results obtained from 34 metastatic cancer patients subjected to DLA in the participating institutions. About 7.5 mL blood processed with CellSearch® was used as “gold standard” reference. DLAs were obtained from 22 metastatic prostate and 12 metastatic breast cancer patients at four different institutions without any noticeable side effects. DLA samples were prepared and processed with different analysis techniques. Processing DLA using CellSearch resulted in a 0–32 fold increase in CTC yield compared to processing 7.5 mL blood. Filtration of DLA through 5 μm pores microsieves was accompanied by large CTC losses. Leukocyte depletion of 18 mL followed by CellSearch yielded an increase of the number of CTC but a relative decrease in yield (37%) versus CellSearch DLA. In four out of seven patients with 0 CTC detected in 7.5 mL of blood, CTC were detected in DLA (range 1–4 CTC). The CTC obtained through DLA enables molecular characterization of the tumor. CTC enrichment technologies however still need to be improved to isolate all the CTC present in the DLA.

What's new?

Circulating tumor cells (CTC) can mirror tumor heterogeneity but a standard blood sample (7.5 mL) is too small to truly represent the tumor. To increase the yield of CTC, the authors used Diagnostic LeukApheresis in which liters of blood are screened for the presence of CTC in metastatic cancer patients. They report a significant increase in CTC yield and consequently, a better molecular characterization of the tumor, encouraging further research into the use of leukapheresis as “liquid biopsy” in cancer patients.

Isolation of circulating tumor cells from pancreatic cancer by automated filtration

It is now widely recognized that the isolation of circulating tumor cells based on cell surface markers might be hindered by variability in their protein expression. Especially in pancreatic cancer, isolation based only on EpCAM expression has produced very diverse results. Methods that are independent of surface markers and therefore independent of phenotypical changes in the circulating cells might increase CTC recovery also in pancreatic cancer. We compared an EpCAM-dependent (IsoFlux) and a size-dependent (automated Siemens Healthineers filtration device) isolation method for the enrichment of pancreatic cancer CTCs. The recovery rate of the filtration based approach is dramatically superior to the EpCAM-dependent approach especially for cells with low EpCAM-expression (filtration: 52%, EpCAM-dependent: 1%). As storage and shipment of clinical samples is important for centralized analyses, we also evaluated the use of frozen diagnostic leukapheresis (DLA) as source for isolating CTCs and subsequent genetic analysis such as KRAS mutation detection analysis. Using frozen DLA samples of pancreatic cancer patients we detected CTCs in 42% of the samples by automated filtration.

Abstract 1723: Diagnostic leukapheresis results in a significant increase in CTC yield in metastatic breast and prostate cancer

Introduction Frequently the number of CTC isolated in 7.5 mL of blood is too small to reliably determine tumor heterogeneity and to be representative as a ‘liquid biopsy’. In the EU FP7 program CTCTrap we aimed to validate and optimize the recently introduced Diagnostic LeukApheresis (DLA; doi: 10.1073/pnas.1313594110) approach to screen liters of blood and thereby substantially increasing the number of CTC available for further characterization. Here we present the results obtained from 32 metastatic cancer patients subjected to DLA in the participating institutions.

Methods Before the DLA procedure, whole blood was drawn in a CellSave blood collection tube and a 7.5 ml aliquot was processed with the ‘gold standard’ reference CellSearch® (Janssen Diagnostics, USA). DLAs from metastatic cancer patients were performed for ≈90 minutes to obtain 40 mL of product containing ≈4x109 mononuclear cells (MNC) representing ≈1 liter of blood. The obtained DLA samples were then divided, fixed with CellSave preservative, prepared and processed with each of the analysis techniques as described in the Standard Operating Procedures developed for DLA in the CTCTrap consortium (https://www.utwente.nl/tnw/mcbp/protocolsandtools/).

Results DLAs were obtained from 20 metastatic prostate cancer patients and 12 metastatic breast cancer patients at four different European academic medical institutions. Using a SOP for the DLA procedure, similar DLA products (MNC concentration: 64x106/mL, SD = 38x106) could be generated without any noticeable side effects. CTC in 7.5 mL of blood ranged from 0 to 324 (mean = 61, median = 18). DLA processed with CellSearch represented 7 to 212 mL of blood (mean = 100, median = 97), CTC ranged from 0 to 2913 (mean = 330, median = 105). Resulting in a significant increase in CTC yield (p = 0.004) ranging from 0x to 40x (mean = 13, median = 9) when comparing 1mL of whole blood to 1mL of DLA. Filtration of 50x106 WBC of DLA, through 5um microsieves yielded only 0 to 12 CTC (mean = 2, median = 0, n = 16). Leukocyte depletion of 18 mL of DLA followed by filtration yielded 0 to 178 CTC (mean = 37, median = 4, n = 22) not yielding a relative increase versus CellSearch DLA. Leukocyte depletion followed by CellSearch yielded 271 to 1620 CTC (mean = 792, median = 484, n = 3) also not yielding a relative increase versus CellSearch DLA. In 7 patients 0 CTC were detected in 7.5mL of blood, in 4 out of these 7 patients CTC were detected in DLA.

Conclusion The yield of CTC can be significantly increased by the use of DLA in patients with CTC detected in 7.5 mL of blood. Technology to select CTC from DLAs will need to be further improved before one can make optimal use of the large processed blood volumes.

Citation Format: Kiki C. Andree, Anouk Mentink, Joost F. Swennenhuis, Leon W. Terstappen, Nikolas H. Stoecklein, Rui P. Neves, Rita Lampignano, Hans Neubauer, Tanja Fehm, Johannes C. Fischer, Elisabetta Rossi, Mariangela Manicone, Umberto Basso, Piero Marson, Rita Zamarchi, Yohann Loriot, Valérie Lapierre, Vincent Faugeroux, Marianne Oulhen, Francoise Farace, Gemma Fowler, Mariane Sousa Fontes, Berni Ebbs, Maryou Lambros, Mateus Crespo, Penelope Flohr, Johann S. de Bono. Diagnostic leukapheresis results in a significant increase in CTC yield in metastatic breast and prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1723. doi:10.1158/1538-7445.AM2017-1723

Abstract 3786: Multicenter evaluation of technology platforms for the enumeration of circulating tumor cells

Metastasis represents the deadliest feature of cancer, which is fueled by circulating tumor cells (CTCs) being released into the bloodstream from the primary tumor. In addition to the clinical value of CTC enumeration for metastatic risk assessment, CTCs are considered to be a minimally invasive source for studying the molecular and genetic features of the disease as well as response to anticancer therapy. Given the molecular heterogeneity of CTCs, which includes loss of epithelial surface marker expression, several microfluidic and filtration technology platforms were developed to overcome the limitations of surface marker dependent CTC enrichment. Here we describe the efforts of the Innovative Medicines Initiative (IMI) consortium CANCER-ID (www.cancer-id.eu), which represents a joint undertaking of experts from academia and pharmaceutical industry, in generating comparative data using different CTC enrichment platforms in a multicenter ring trial.

To address clinically relevant subtypes of Non-Small Cell Lung Cancer (NSCLC), different NSCLC cell lines were profiled for genetic aberrations (mutations and copy number aberrations), expression of epithelial markers (epithelial cell adhesion molecule (EPCAM) and cytokeratins) as well as cell size. Cell lines were selected to generate spike-in samples using blood of healthy volunteers with informed consent in a centralized way. Analysis was performed by at least three CANCER-ID partners using different CTC enrichment technologies including the Siemens filtration device, the Parsortix PR1, VyCap filtration and the CellSearch system.

To ensure quality and comparability of results, CANCER-ID partners established standard operation procedures (SOPs) for pre-analytic sample handling including sample fixation, storage and shipment. Special attention was paid on the development of SOPs for the actual CTC enrichment procedure and the integration of downstream applications including single cell isolation by DEPArray™ followed by Ampli1™ WGA and molecular and genetic characterization of isolated cells. Epitope-independent enrichment by filtration or microfluidic devices was evaluated by using NSCLC cells with substantially different cell size. In addition, comparative data on spike-in samples was generated using the EPCAM-expression dependent CellSearch system, which failed to detect EPCAM-negative tumor cells.

In conclusion, the evaluation of different CTC enrichment technologies and the integration of workflows for downstream analysis of single cells blaze the trail for the next phase of IMI’s CANCER-ID, which includes the analysis of real-life NSCLC patient material.

This work is supported by IMI JU & EFPIA (grant no. 115749).

Citation Format: Sebastian Bender, Merlin V. Lütke-Eversloh, Rui P. Neves, NNikolas H. Stoecklein, Leon W. Terstappen, Barbara Baggiani, Martin H. Neumann, Thomas Krahn, Klaus Pantel, Thomas Schlange, Leonie L. Zeune. Multicenter evaluation of technology platforms for the enumeration of circulating tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3786. doi:10.1158/1538-7445.AM2017-3786

Abstract 513: Standardization of technologies for CTC, ctDNA and miRNA enrichment, isolation and analysis for liquid biopsies during the first year of IMI's CANCER-ID

Within the European Innovative Medicines Initiative (IMI) consortium CANCER-ID (www.cancer-id.eu), scientists at academic, clinical and industrial sites across Europe and in the US joined forces to evaluate innovative technologies in the field of liquid cancer biopsies. This project aims at implementing standard operating procedures (SOPs) for pre-analytical sample handling, enrichment, isolation and analysis of Circulating Tumor Cells (CTCs), circulating free tumor DNA (ctDNA) and microRNAs (miRNAs) as novel blood-based biomarkers, with a focus on Non-Small Cell Lung Cancer (NSCLC) and HER2-treatment refractory breast cancer. In order to determine sensitivity and specificity of different technologies for CTC isolation and analysis (e.g. detection of mutations, amplifications, protein phosphorylation), complex samples comprising a mixture of NSCLC or breast cancer cell lines spiked in healthy donor blood were distributed to different CANCER-ID partner sites. These cell lines have been selected based on their molecular/genetic properties to reflect clinically relevant subtypes of the disease and have been further characterized in terms of cell-surface marker expression and cell size distribution. The use of complex spiked samples better models the heterogeneity of real-life patient material. Furthermore, healthy donor and patient derived plasma samples are investigated using different technology platforms to validate tumor-specific miRNA or ctDNA profiles that might characterize molecular tumor subtypes. To this end, differences in exosome-derived versus free circulating miRNAs are of special interest. As for CTCs the development of ctDNA and miRNA standards that can be used to compare and validate different technologies are in the focus of this effort. In summary, our results pave the way for the next phase of CANCER-ID, which includes the analysis of cancer patient samples in clinical studies using different technologies and thereby advance the concept of liquid biopsy particularly in indications in which conventional tissue biopsies are difficult to obtain.

Citation Format: Thomas Schlange, Nikolas Stoecklein, Rui P. Neves, Sabrina Pleier, Sebastian Bender, Nora Brychta, Merlin V. Luetke-Eversloh, Kiki Andree, Leon Terstappen, Thomas Krahn, Thomas Krahn. Standardization of technologies for CTC, ctDNA and miRNA enrichment, isolation and analysis for liquid biopsies during the first year of IMI's CANCER-ID. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 513.

Abstract 1532: The isolation of CTC from diagnostic leukapheresis

Introduction

At present, the CellSearch system is the only validated method for the detection of circulating tumor cells (CTC) that has been cleared by the U.S. Food and Drug Administration. This system, designed for the enumeration of CTC in 7.5 mL of blood, detects CTC based on their expression of EpCAM and cytokeratins and negativity for CD45. However, the number of CTC that are detected in patients with metastatic carcinomas is in most cases too small to reliably determine tumor heterogeneity and to be representative as a ‘liquid biopsy’. Our aim is to identify and isolate a sufficient number of circulating tumor cells in virtually all metastatic cancer patients to enable their characterization and to represent a real-time liquid biopsy. For this purpose we used Diagnostic LeukApheresis (DLA) to increase the blood volume to be analyzed. We developed several techniques to isolate CTC from DLA to enable a multicenter comparison of CTC detection in DLA products.

Methods

DLAs were performed for ∼1 hour to obtain 40 mL of product containing ∼4 x10⁁9 mononuclear cells representing ∼1 liter of blood. Using CellSearch a maximum of 2 mL of DLA could be processed for EpCAM+ CTC (Fisher et al. doi: 10.1073/pnas.1313594110) and EpCAM- CTC (de Wit et al doi: 10.1038/srep12270). Using filtration through microsieves with 5 μm pores a maximum of 1.0 mL of DLA could be processed. To process 18 mL DLA product protocols were developed for leukocyte depletion using RosetteSep™ (StemCell Technologies, USA) and for EpCAM selection using an anti-EpCAM coated column (Leukocare AG). All enriched cell fractions were stained using CD45 PerCP, Cytokeratins PE and the nuclear dye DAPI, followed by fluorescence microscopy scanning and analysis.

Results

Leukocyte depletion using the RosetteSep™ CTC Enrichment cocktail was first optimized using small sample volumes (1 mL) spiked with cells from cancer cell lines. Depletion of leukocytes ranged from 3.1 to 3.9 logs with an average recovery of spiked cancer cells of 50-60%. Isolation of CTC expressing EpCAM was pursued using anti-EpCAM coated columns and optimized for selection and release of EpCAM expressing cells by passage of cells from cancer cell lines through the column resulting in 34-100% recovery. Both procedures were scaled up to enable processing of 18 mL of DLA. Leukocytes were depleted using RosetteSepTM by 3.1 - 3.9 logs whereas with anti-EpCAM columns only 1.7 - 1.8 logs depletion were reached. Using RosetteSepTM 21% and with the anti-EpCAM coated columns 2% of the tumor cells spiked into 18ml DLA were recovered.

Conclusion

Standard operating procedures were developed to isolate CTC in DLA's from breast, prostate cancer and lung cancer patients for evaluation and comparison in the EU sponsored consortiums CTCTrap (www.utwente.nl/tnw/ctctrap/) and CANCER-ID (www.CANCER-ID.eu). Isolation of EpCAM expressing CTC using the anti-EpCAM coated columns will need further optimization before it can proceed to multicenter comparison.

Citation Format: Kiki C. Andree, Anouk Mentink, Martin Scholz, Roland Kirchner, Rui P. Neves, Christiane Driemel, Rita Lampignano, Hans Neubauer, Dieter Niederacher, Tanja Fehm, Wolfram T. Knoefel, Johannes C. Fischer, Nikolas H. Stoecklein, Leon WMM Terstappen. The isolation of CTC from diagnostic leukapheresis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1532.

Isolation of cellulolytic fungi from waste of castor (Ricinus communis L.)

This is the first report of isolation of fungi present in fatty and defatted castor bean meal as well as the first of crop's selection to test the cellulolytic potential, in order to verify the diversity and potential of cellulolytic fungi in castor bean waste (Ricinus communis L.). For the screening on solid medium, it was used carboxymethylcellulose (CMC) as the sole carbon source. The microcrystalline cellulose (Avicel) was used as a substrate for submerged fermentation for production of cellobiohydrolase (FPase) and the CMC to produce endoglucanases (CMCase) and β-glycosidases (BG). 189 cultures of fungi were isolated, including 40 species of filamentous fungi and three yeasts. The Aspergillus was the most frequent found genus. Regarding the distribution of isolated species from defatted castor bean meal, the A. niger was the most frequent one; and within the fatty castor bean meal, the Emericela variecolor prevailed among other species. Among the 67 fungal cultures tested in the initial screening on solid media to assess the cellulolytic potential, 54 disclosed Cellulolytic Index (CI) ranging from 1.04 to 6.00 mm. The isolates were selected for enzyme production in liquid medium with values above 2.0 CI. They were obtained with A. japonicus URM5620 FPase activity (4.99 U/ml) and BG (0.05 U/ml), and Rhodotorula glutinis URM5724 activity of CMCase 3.58 U/ml. These cases occurred after 168 h of submersion for both species of fungi. In our study, we could conclude that the castor bean is a promising source of fungi capable of producing cellulolytic enzymes.

Antifungal activity of the naphthoquinone beta-lapachone against disseminated infection with Cryptococcus neoformans var. neoformans in dexamethasone-immunosuppressed Swiss mice

The in vivo antifungal activity of the naphthoquinone beta-lapachone against disseminated infection by Cryptococcus neoformans was investigated. Swiss mice were immunosuppressed daily with dexamethasone (0.5 mg per mouse) intraperitoneally for 3 days, the procedure was repeated 4 days later, and the animals were then challenged intravenously with C. neoformans (10(6) CFU/mL) 1 week later. Seven days after infection, the mice were divided into groups and treated daily with beta-lapachone (10 mg/kg, iv) for 7 (N = 6) and 14 days (N = 10). Amphotericin B (0.5 mg/kg) was used as comparator drug and an additional group received PBS. Treatment with beta-lapachone cleared the yeast from the spleen and liver, and the fungal burden decreased approximately 10(4) times in the lungs and brain 14 days after infection when compared to the PBS group (P < 0.05). This result was similar to that of the amphotericin B-treated group. Protection was suggestively due to in vivo antifungal activity of this drug and apparently not influenced by activation of the immune response, due to similar leukocyte cell counts among all groups. This study highlights the prospective use of beta-lapachone for treatment of disseminated cryptococcosis.

Relationship of mercury with aluminum, iron and manganese oxy-hydroxides in sediments from the Alto Pantanal, Brazil

Sediments from nine floodplain lakes in Pantanal were analyzed for a large-scale (300 km) survey of mercury (Hg) load in sediments and soils of the Alto Pantanal and to study the relationship between Hg and reactive aluminum, iron, and manganese oxy-hydroxides. The results were compared with the Hg content in river and stream sediments from the Poconé gold mining area, where Hg has been extensively used and still is in use. The results indicate that the Hg concentrations were elevated in river sediment close to the mining area in Bento Gomes river basin (average in the < 74-microm fraction 88.9 ng Hg g(-1) dry wt.; interquartile range 50.3-119.5), but there was no clear indication that the local Hg emissions have contaminated the remote floodplain lakes, where concentrations were surprisingly low (average in the < 74-microm fraction 33.2 ng Hg g(-1) dry wt. sediment; interquartile range 18.4-46.8), in particular when considering geochemical characteristics of the sediment. The sediment from the floodplain lakes contained less Hg-tot and more reactive iron oxy-hydroxides than soils from the Tapajós area in the Amazon basin. This resulted in a mass ratio between Hg and amorphous oxy-hydroxides of only 5 x 10(-6) for Hg-tot/Fe-oxa (interquartile range 3-7 x 10(-6).