Showing papers by "Rakesh K. Jain published in 2010"

Delivering nanomedicine to solid tumors

Abstract: Recent advances in nanotechnology have offered new hope for cancer detection, prevention, and treatment. While the enhanced permeability and retention effect has served as a key rationale for using nanoparticles to treat solid tumors, it does not enable uniform delivery of these particles to all regions of tumors in sufficient quantities. This heterogeneous distribution of therapeutics is a result of physiological barriers presented by the abnormal tumor vasculature and interstitial matrix. These barriers are likely to be responsible for the modest survival benefit offered by many FDA-approved nanotherapeutics and must be overcome for the promise of nanomedicine in patients to be realized. Here, we review these barriers to the delivery of cancer therapeutics and summarize strategies that have been developed to overcome these barriers. Finally, we discuss design considerations for optimizing the delivery of nanoparticles to tumors.

Malignant cells facilitate lung metastasis by bringing their own soil

Abstract: Metastatic cancer cells (seeds) preferentially grow in the secondary sites with a permissive microenvironment (soil). We show that the metastatic cells can bring their own soil—stromal components including activated fibroblasts—from the primary site to the lungs. By analyzing the efferent blood from tumors, we found that viability of circulating metastatic cancer cells is higher if they are incorporated in heterotypic tumor–stroma cell fragments. Moreover, we show that these cotraveling stromal cells provide an early growth advantage to the accompanying metastatic cancer cells in the lungs. Consistent with this hypothesis, we demonstrate that partial depletion of the carcinoma-associated fibroblasts, which spontaneously spread to the lung tissue along with metastatic cancer cells, significantly decreases the number of metastases and extends survival after primary tumor resection. Finally, we show that the brain metastases from lung carcinoma and other carcinomas in patients contain carcinoma-associated fibroblasts, in contrast to primary brain tumors or normal brain tissue. Demonstration of the direct involvement of primary tumor stroma in metastasis has important conceptual and clinical implications for the colonization step in tumor progression.

Phase II Study of Cediranib, an Oral Pan–Vascular Endothelial Growth Factor Receptor Tyrosine Kinase Inhibitor, in Patients With Recurrent Glioblastoma

Abstract: Purpose Glioblastoma is an incurable solid tumor characterized by increased expression of vascular endothelial growth factor (VEGF). We performed a phase II study of cediranib in patients with recurrent glioblastoma. Methods Cediranib, an oral pan-VEGF receptor tyrosine kinase inhibitor, was administered (45 mg/d) until progression or unacceptable toxicity to patients with recurrent glioblastoma. The primary end point was the proportion of patients alive and progression free at 6 months (APF6). We performed magnetic resonance imaging (MRI) and plasma and urinary biomarker evaluations at multiple time points. Results Thirty-one patients with recurrent glioblastoma were accrued. APF6 after cediranib was 25.8%. Radiographic partial responses were observed by MRI in 17 (56.7%) of 30 evaluable patients using three-dimensional measurements and in eight (27%) of 30 evaluable patients using two-dimensional measurements. For the 15 patients who entered the study taking corticosteroids, the dose was reduced (n = 10...

Tumor Microvasculature and Microenvironment: Novel Insights Through Intravital Imaging in Pre‐Clinical Models

Abstract: Intravital imaging techniques have provided unprecedented insight into tumor microcirculation and microenvironment. For example, these techniques allowed quantitative evaluations of tumor blood vasculature to uncover its abnormal organization, structure and function (e.g., hyper-permeability, heterogeneous and compromised blood flow). Similarly, imaging of functional lymphatics has documented their absence inside tumors. These abnormalities result in elevated interstitial fluid pressure and hinder the delivery of therapeutic agents to tumors. In addition, they induce a hostile microenvironment characterized by hypoxia and acidosis, as documented by intravital imaging. The abnormal microenvironment further lowers the effectiveness of anti-tumor treatments such as radiation therapy and chemotherapy. In addition to these mechanistic insights, intravital imaging may also offer new opportunities to improve therapy. For example, tumor angiogenesis results in immature, dysfunctional vessels--primarily caused by an imbalance in production of pro- and anti-angiogenic factors by the tumors. Restoring the balance of pro- and anti-angiogenic signaling in tumors can "normalize" tumor vasculature and thus, improve its function, as demonstrated by intravital imaging studies in preclinical models and in cancer patients. Administration of cytotoxic therapy during periods of vascular normalization has the potential to enhance treatment efficacy.

A Nanoparticle Size Series for In Vivo Fluorescence Imaging

Abstract: Any design of nanoparticle vectors for cancer therapy or imaging must take into account the interaction of the nanoparticles with the tumor microenvironment. Size, charge, and shape have been shown to dominate this interaction.[1, 2] In vivo probing of solid tumors with particles of different sizes simultaneously has thus far been challenging due to the limitations of available nano-sized probes.[3–5] Fluorescent dextrans and other macromolecule probes have been used in studies with intravital microscopy, but heterogeneities across samples has prevented their use for the simultaneous imaging of a size series of probes within the same tumour.[5] MRI contrast agents are another attractive set of probes due to the minimally-invasive nature of the technology,[6, 7] but the lower spatial resolution of MRI limits the imaging of heterogeneity within tumors, and the technique does not allow for simultaneous imaging and tracking of a size series of probes within the same tumor.

A nanoparticle size series for in vivo fluorescence imaging

Abstract: Any design of nanoparticle vectors for cancer therapy or imaging must take into account the interaction of the nanoparticles with the tumor microenvironment. Size, charge, and shape have been shown to dominate this interaction.[1, 2] In vivo probing of solid tumors with particles of different sizes simultaneously has thus far been challenging due to the limitations of available nano-sized probes.[3–5] Fluorescent dextrans and other macromolecule probes have been used in studies with intravital microscopy, but heterogeneities across samples has prevented their use for the simultaneous imaging of a size series of probes within the same tumour.[5] MRI contrast agents are another attractive set of probes due to the minimally-invasive nature of the technology,[6, 7] but the lower spatial resolution of MRI limits the imaging of heterogeneity within tumors, and the technique does not allow for simultaneous imaging and tracking of a size series of probes within the same tumor.

Compact Biocompatible Quantum Dots via RAFT-Mediated Synthesis of Imidazole-Based Random Copolymer Ligand

Abstract: We present a new class of polymeric ligands for quantum dot (QD) water solubilization to yield biocompatible and derivatizable QDs with compact size (∼10−12 nm diameter), high quantum yields (>50%), excellent stability across a large pH range (pH 5−105), and low nonspecific binding To address the fundamental problem of thiol instability in traditional ligand exchange systems, the polymers here employ a stable multidentate imidazole binding motif to the QD surface The polymers are synthesized via reversible addition−fragmentation chain transfer-mediated polymerization to produce molecular weight controlled monodisperse random copolymers from three types of monomers that feature imidazole groups for QD binding, polyethylene glycol (PEG) groups for water solubilization, and either primary amines or biotin groups for derivatization The polymer architecture can be tuned by the monomer ratios to yield aqueous QDs with targeted surface functionalities By incorporating amino-PEG monomers, we demonstrate cova

Recruitment of myeloid but not endothelial precursor cells facilitates tumor regrowth after local irradiation.

Abstract: Tumor neovascularization and growth might be promoted by the recruitment of bone marrow–derived cells (BMDC), which include endothelial precursor cells and “vascular modulatory” myelomonocytic (CD11b+) cells. BMDCs may also drive tumor regrowth after certain chemotherapeutic and vascular disruption treatments. In this study, we evaluated the role of BMDC recruitment in breast and lung carcinoma xenograft models after local irradiation (LI). We depleted the bone marrow by including whole-body irradiation (WBI) of 6 Gy as part of a total tumor dose of 21 Gy, and compared the growth delay with the one achieved after LI of 21 Gy. In both models, the inclusion of WBI induced longer tumor growth delays. Moreover, WBI increased lung tumor control probability by LI. Exogenous delivery of BMDCs from radiation-naive donors partially abrogated the WBI effect. Myeloid BMDCs, primarily macrophages, rapidly accumulated in tumors after LI. Intratumoral expression of stromal-derived factor 1α (SDF-1α), a chemokine that promotes tissue retention of BMDCs, was noted 2 days after LI. Conversely, treatment with an inhibitor of SDF-1α receptor CXCR4 (AMD3100) with LI significantly delayed tumor regrowth. However, when administered starting from 5 days post-LI, AMD3100 treatment was ineffective. Lastly, with restorative bone marrow transplantation of Tie2-GFP–labeled BMDC population, we observed an increased number of monocytes but not endothelial precursor cells in tumors that recurred following LI. Our results suggest that an increase in intratumoral SDF-1α triggered by LI recruits myelomonocytes/macrophages which promotes tumor regrowth. Cancer Res; 70(14); 5679–85. ©2010 AACR.

Diffusion of Particles in the Extracellular Matrix: The Effect of Repulsive Electrostatic Interactions

Abstract: Diffusive transport of macromolecules and nanoparticles in charged fibrous media is of interest in many biological applications, including drug delivery and separation processes Experimental findings have shown that diffusion can be significantly hindered by electrostatic interactions between the diffusing particle and charged components of the extracellular matrix The implications, however, have not been analyzed rigorously Here, we present a mathematical framework to study the effect of charge on the diffusive transport of macromolecules and nanoparticles in the extracellular matrix of biological tissues The model takes into account steric, hydrodynamic, and electrostatic interactions We show that when the fiber size is comparable to the Debye length, electrostatic forces between the fibers and the particles result in slowed diffusion However, as the fiber diameter increases the repulsive forces become less important Our results explain the experimental observations that neutral particles diffuse faster than charged particles Taken together, we conclude that optimal particles for delivery to tumors should be initially cationic to target the tumor vessels and then change to neutral charge after exiting the blood vessels

p53 Controls Radiation-Induced Gastrointestinal Syndrome in Mice Independent of Apoptosis

Abstract: Acute exposure to ionizing radiation can cause lethal damage to the gastrointestinal (GI) tract, a condition called the GI syndrome. Whether the target cells affected by radiation to cause the GI syndrome are derived from the epithelium or endothelium and whether the target cells die by apoptosis or other mechanisms are controversial issues. Studying mouse models, we found that selective deletion of the proapoptotic genes Bak1 and Bax from the GI epithelium or from endothelial cells did not protect mice from developing the GI syndrome after sub-total-body gamma irradiation. In contrast, selective deletion of p53 from the GI epithelium, but not from endothelial cells, sensitized irradiated mice to the GI syndrome. Transgenic mice overexpressing p53 in all tissues were protected from the GI syndrome after irradiation. These results suggest that the GI syndrome is caused by the death of GI epithelial cells and that these epithelial cells die by a mechanism that is regulated by p53 but independent of apoptosis.

Simultaneous measurement of RBC velocity, flux, hematocrit and shear rate in vascular networks

Abstract: Not all tumor vessels are equal. Tumor-associated vasculature includes immature vessels, regressing vessels, transport vessels undergoing arteriogenesis and peritumor vessels influenced by tumor growth factors. Current techniques for analyzing tumor blood flow do not discriminate between vessel subtypes and only measure average changes from a population of dissimilar vessels. We developed methodologies for simultaneously quantifying blood flow (velocity, flux, hematocrit and shear rate) in extended networks at single-capillary resolution in vivo. Our approach relies on deconvolution of signals produced by labeled red blood cells as they move relative to the scanning laser of a confocal or multiphoton microscope and provides fully resolved three-dimensional flow profiles within vessel networks. Using this methodology, we show that blood velocity profiles are asymmetric near intussusceptive tissue structures in tumors in mice. Furthermore, we show that subpopulations of vessels, classified by functional parameters, exist in and around a tumor and in normal brain tissue.

InAs(ZnCdS) quantum dots optimized for biological imaging in the near-infrared.

Abstract: We present the synthesis of InAs quantum dots (QDs) with a ZnCdS shell with bright and stable emission in the near-infrared (NIR, 700-900 nm) region for biological imaging applications. We demonstrate how NIR QDs can image tumor vasculature in vivo at significantly deeper penetration depths and with higher contrast than visible emitting CdSe(CdS) QDs. Targeted cellular labeling is also presented and may enable multiplexed and low autofluorescence cellular imaging.

In vivo wide-area cellular imaging by side-view endomicroscopy

Abstract: In vivo imaging of small animals offers several possibilities for studying normal and disease biology, but visualizing organs with single-cell resolution is challenging. We describe rotational side-view confocal endomicroscopy, which enables cellular imaging of gastrointestinal and respiratory tracts in mice and may be extensible to imaging organ parenchyma such as cerebral cortex. We monitored cell infiltration, vascular changes and tumor progression during inflammation and tumorigenesis in colon over several months.

In vivo imaging of tumors.

Abstract: INTRODUCTION Light microscopy of tumors, as for other thick, scattering tissues such as the brain or the developing embryo, is limited by light penetration and optical access. because of these problems, epifluorescence and confocal microscopy are typically limited to the outer 50-100 microm of the accessible tumor tissue. Most mouse tumors must be exteriorized for examination under the light microscope, a procedure that limits the duration and repeatability of imaging. this protocol describes the generation of chronic window preparations in the mouse. These preparations allow an implanted tumor to grow for several weeks in an optically accessible location in vivo, making it possible to examine the living tumor with high-resolution light microscopy in a repetitive manner. Two chronic window preparations are described: (1) the dorsal skinfold chamber, which allows in vivo imaging of tumors growing in the subcutaneous space, and (2) the cranial window, which allows in vivo imaging of tumors growing on the brain surface.

Infiltrative patterns of glioblastoma spread detected via diffusion MRI after treatment with cediranib

Abstract: To evaluate the role of apparent diffusion coefficient (ADC) imaging in assessing tumor cell infiltration after treatment with the antivascular endothelial growth factor (anti-VEGF) agent, cediranib, we prospectively analyzed diffusion MRI scans from 30 patients participating in a Phase II trial of cediranib for recurrent glioblastoma. A patient-specific threshold was selected below which ADC values were determined to be abnormally low and suggestive of tumor. We determined the percent of low ADC in the FLAIR hyperintensity surrounding the enhancing tumor and then visualized the location of these low ADC voxels. The percent volume of the FLAIR hyperintensity comprised by low ADC increased significantly from baseline (2.3%) to day 28 (2.9%), day 56 (5.0%), and day 112 (6.3%) of treatment with cediranib suggesting increasing infiltrative tumor in some patients. Visualization of the location of the low ADC voxels suggested regions of tumor growth that were not visible on contrast-enhanced MRI. ADC maps can be used to suggest regions of infiltrative tumor cells with anti-VEGF therapy and should be validated in future studies.

Angiopoietin-2 Interferes with Anti-VEGFR2–Induced Vessel Normalization and Survival Benefit in Mice Bearing Gliomas

Abstract: Purpose: In brain tumors, cerebral edema is a significant source of morbidity and mortality. Recent studies have shown that inhibition of vascular endothelial growth factor (VEGF) signaling induces transient vascular normalization and reduces cerebral edema, resulting in a modest survival benefit in glioblastoma patients. During anti-VEGF treatment, circulating levels of angiopoietin (Ang)-2 remained high after an initial minor reduction. It is not known, however, whether Ang-2 can modulate anti-VEGF treatment of glioblastoma. Here, we used an orthotopic glioma model to test the hypothesis that Ang-2 is an additional target for improving the efficacy of current anti-VEGF therapies in glioma patients. Experimental Design: To recapitulate high levels of Ang-2 in glioblastoma patients during anti-VEGF treatment, Ang-2 was ectopically expressed in U87 glioma cells. Animal survival and tumor growth were assessed to determine the effects of Ang-2 and anti–VEGF receptor 2 (VEGFR2) treatment. We also monitored morphologic and functional vascular changes using multiphoton laser scanning microscopy and immunohistochemistry. Results: Ectopic expression of Ang-2 had no effect on vascular permeability, tumor growth, or survival, although it resulted in higher vascular density, with dilated vessels and reduced mural cell coverage. On the other hand, when combined with anti-VEGFR2 treatment, Ang-2 destabilized vessels without affecting vessel regression and compromised the survival benefit of VEGFR2 inhibition by increasing vascular permeability. VEGFR2 inhibition normalized tumor vasculature whereas ectopic expression of Ang-2 diminished the beneficial effects of VEGFR2 blockade by inhibiting vessel normalization. Conclusion: Cancer treatment regimens combining anti-VEGF and anti-Ang-2 agents may be an effective strategy to improve the efficacy of current anti-VEGF therapies. Clin Cancer Res; 16(14); 3618–27. ©2010 AACR.

Simultaneous measurement of RBC velocity, flux, hematocrit and shear rate in vascular networks in vivo

Abstract: nAture methods | VOL.7 NO.8 | august 2010 | 655 not all tumor vessels are equal. tumor-associated vasculature includes immature vessels, regressing vessels, transport vessels undergoing arteriogenesis and peritumor vessels influenced by tumor growth factors. current techniques for analyzing tumor blood flow do not discriminate between vessel subtypes and only measure average changes from a population of dissimilar vessels. We developed methodologies for simultaneously quantifying blood flow (velocity, flux, hematocrit and shear rate) in extended networks at single-capillary resolution in vivo. our approach relies on deconvolution of signals produced by labeled red blood cells as they move relative to the scanning laser of a confocal or multiphoton microscope and provides fully resolved three-dimensional flow profiles within vessel networks. using this methodology, we show that blood velocity profiles are asymmetric near intussusceptive tissue structures in tumors in mice. Furthermore, we show that subpopulations of vessels, classified by functional parameters, exist in and around a tumor and in normal brain tissue.

Degradation of 4-Nitrophenol, 2-Chloro-4-nitrophenol, and 2,4-Dinitrophenol by Rhodococcus imtechensis Strain RKJ300

Abstract: A bacterial strain Rhodococcus imtechensis RKJ300 (= MTCC 7085(T) = JCM 13270(T)) was isolated from pesticide-contaminated soil of Punjab by the enrichment technique on minimal medium containing 4-nitrophenol. Strain RKJ300 is capable of utilizing 4-nitrophenol, 2-chloro-4-nitrophenol, and 2,4-dinitrophenol as sole sources of carbon and energy. The strain involved both oxidative and reductive catabolic mechanisms for initial transformation of these compounds. In the case of 2-chloro-4-nitrophenol, colorimetric analysis indicated that nitrite release was followed by stoichiometric elimination of chloride ions. Experiments using whole cells and cell-free extracts showed chlorohydroquinone and hydroquinone as the intermediates of 2-chloro-4-nitrophenol degradation. This is the first report of degradation on 2-chloro-4-nitrophenol by a bacterium under aerobic condition to the best of our knowledge. However, pathways for degradation of 4-nitrophenol and 2,4-dinitrophenol were similar to those reported in other strains of Rhodococcus. Laboratory-scale soil microcosm studies demonstrated that the organism was capable of degrading a mixture of nitrophenols simultaneously, indicating its applicability toward in situ bioremediation of contaminated sites. The fate of the augmented strain as monitored by the plate-counting method and hybridization technique was found to be fairly stable throughout the period of microcosm experiments.

Plasma soluble VEGFR-1 is a potential dual biomarker of response and toxicity for bevacizumab with chemoradiation in locally advanced rectal cancer.

Abstract: We explored plasma and urinary concentrations of two members of the vascular endothelial growth factor (VEGF) family and their receptors as potential response and toxicity biomarkers of bevacizumab with neoadjuvant chemoradiation in patients with localized rectal cancer. The concentrations of VEGF, placental growth factor (PlGF), soluble VEGF receptor 1 (sVEGFR-1), and sVEGFR-2 were measured in plasma and urine at baseline and during treatment. Pretreatment values and changes over time were analyzed as potential biomarkers of pathological response to treatment as well as for acute toxicity in patients with locally advanced rectal cancer treated prospectively in 2002-2008 with neoadjuvant bevacizumab, 5-fluorouracil, radiation therapy, and surgery in a phase I/II trial. Of all biomarkers, pretreatment plasma sVEGFR-1-an endogenous blocker of VEGF and PlGF, and a factor linked with "vascular normalization"-was associated with both primary tumor regression and the development of adverse events after neoadjuvant bevacizumab and chemoradiation. Based on the findings in this exploratory study, we propose that plasma sVEGFR-1 should be further studied as a potential biomarker to stratify patients in future studies of bevacizumab and/or cytotoxics in the neoadjuvant setting.

Anti–Vascular Endothelial Growth Factor Therapies as a Novel Therapeutic Approach to Treating Neurofibromatosis-Related Tumors

Abstract: Patients with bilateral vestibular schwannomas associated with neurofibromatosis type 2 (NF2) experience significant morbidity such as complete hearing loss. We have recently shown that treatment with bevacizumab provided tumor stabilization and hearing recovery in a subset of NF2 patients with progressive disease. In the current study, we used two animal models to identify the mechanism of action of anti-vascular endothelial growth factor (VEGF) therapy in schwannomas. The human HEI193 and murine Nf2(-/-) cell lines were implanted between the pia and arachnoid meninges as well as in the sciatic nerve to mimic central and peripheral schwannomas. Mice were treated with bevacizumab (10 mg/kg/wk i.v.) or vandetanib (50 mg/kg/d orally) to block the VEGF pathway. Using intravital and confocal microscopy, together with whole-body imaging, we measured tumor growth delay, survival rate, as well as blood vessel structure and function at regular intervals. In both models, tumor vessel diameter, length/surface area density, and permeability were significantly reduced after treatment. After 2 weeks of treatment, necrosis in HEI193 tumors and apoptosis in Nf2(-/-) tumors were significantly increased, and the tumor growth rate decreased by an average of 50%. The survival of mice bearing intracranial schwannomas was extended by at least 50%. This study shows that anti-VEGF therapy normalizes the vasculature of schwannoma xenografts in nude mice and successfully controls the tumor growth, probably by reestablishing a natural balance between VEGF and semaphorin 3 signaling.

Estimating the prevalence of dry eye among Indian patients attending a tertiary ophthalmology clinic.

Abstract: McMonnies' and Ocular Surface Disease Index (OSDI) questionnaires were used to estimate the prevalence of dry eye among 400 consecutive patients aged >40 years attending the ophthalmology outpatient department of the Lady Hardinge Medical College and associated Smt Sucheta Kriplani Hospital, in New Delhi, India. These estimates were then compared with the results of various clinical tests and examinations of the same patients, including Schirmer's tests, evaluations of tear-film breakup times and fluorescein staining of corneas. Although the overall prevalence of dry eye based on OSDI was 29.25%, there was considerable age- and gender-related variation in this parameter. Compared with the younger patients, those aged >or=80 years were more likely to have OSDI that were indicative of dry eye (41.2%), and the women investigated were more likely to have dry eye (as indicated by OSDI) than the men (27% v. 12%). Occupation, however, appeared to have no effect on the risk of dry eye (P=0.952). Grittiness was the commonest complaint reported. McMonnies' indices (MMI), OSDI and the values recorded in Schirmer's tests were all significantly and positively correlated with the probability of a clinical diagnosis of dry eye (P<0.001 for each). Only patients with a Schirmer's value of <8 mm showed fluorescein staining of the cornea (P<0.005). This appears to be the first report from India in which MMI and OSDI have been significantly correlated with the probability of a clinical diagnosis of dry eye. Although the subjects were recruited in an ophthalmology department and may not have been very representative of the general population of New Delhi, dry-eye syndrome is probably common in the study area and probably has a considerable socio-economic impact. The early detection and timely management of this syndrome is important, as they can help prevent long-term sequelae and sight-threatening complications.

An antibiotic, heavy metal resistant and halotolerant Bacillus cereus SIU1 and its thermoalkaline protease

Abstract: Background: Many workers have reported halotolerant bacteria from saline conditions capable of protease production. However, antibiotic resistance and heavy metal tolerance pattern of such organisms is not documented very well. Similarly, only a few researchers have reported the pattern of pH change of fermentation medium during the course of protease production. In this study, we have isolated a halotolerant Bacillus cereus SIU1 strain from a non-saline environment and studied its antibiotic and heavy metal resistance pattern. The isolate produces a thermoalkaline protease and changes the medium pH during the course of fermentation. Thermostability of protease was also studied for 30 min. Results: Seventy bacterial strains isolated from the soils of Eastern Uttar Pradesh, India were screened for protease production. All of them exhibited protease activity. However, 40% bacterial isolates were found good protease producers as observed by caseinolytic zones on milk agar plates. Among them, culture S-4 was adjudged as the best protease producer, and was identified as Bacillus cereus by morphological, biochemical and 16 S rDNA sequence analyses. The isolate was resistant to heavy metals (As 2+ ,P b 2+ ,C s 1+ ) and antibiotics (penicillin, lincomycin, cloxacillin, pefloxacin). Its growth behavior and protease production was studied at 45°C and pH 9.0. The protease units of 88 ml -1 were noted in unoptimized modified glucose yeast extract (GYE) medium during early stationary phase at 20 h incubation period. The enzyme was stable in the temperature range of 35°-55°C. Conclusions: An antibiotic and heavy metal resistant, halotolerant Bacillus cereus isolate is capable of producing thermoalkaline protease, which is active and stable at pH 9.0 and 35°-55°C. This isolate may be useful in several industrial applications owing to its halotolerance and antibiotic and heavy metal resistance characteristics.

p-Nitrophenol Degradation via 4-Nitrocatechol in Burkholderia sp. SJ98 and Cloning of Some of the Lower Pathway Genes

Abstract: Microbial degradation studies have pointed toward the occurrence of two distinct PNP catabolic pathways in Gram positive and Gram negative bacteria. The former involves 4-nitrocatechol (4-NC), 1,2,4-benzenetriol (BT), and maleylacetate (MA) as major degradation intermediates, whereas the later proceeds via formation of 1,4-benzoquinone (BQ) and hydroquinone (HQ). In the present study we identified a Gram negative organism viz. Burkholderia sp. strain SJ98 that degrades PNP via 4NC, BT, and MA. A 6.89 Kb genomic DNA fragment of strain SJ98 that encompasses seven putatively identified ORFs (orfA, pnpD, pnpC, orfB, orfC, orfD, and orfE) was cloned. PnpC is benzenetriol dioxygenase belonging to the intradiol dioxygenase superfamily, whereas PnpD is identified as maleylacetate reductase, a member of the Fe-ADH superfamily showing NADH dependent reductase activity. The in vitro activity assays carried out with purified pnpC and pnpD (btd and mar) gene products transformed BT to MA and MA to beta-ketoadipate, respectively. The cloning, sequencing, and characterization of these genes along with the functional PNP degradation studies ascertained the involvement of 4-NC, BT, and MA as degradation intermediates of PNP pathway in this strain. This is one of the first conclusive reports for 4-NC and BT mediated degradation of PNP in a Gram negative organism.

A Safety and Survival Analysis of Neoadjuvant Bevacizumab with Standard Chemoradiation in a Phase I/II Study Compared with Standard Chemoradiation in Locally Advanced Rectal Cancer

Abstract: Introduction. Bevacizumab is increasingly being tested with neoadjuvant regimens in patients with localized cancer, but its effects on metastasis and survival remain unknown. This study examines the long-term outcome of clinical stage II/III rectal cancer patients treated in a prospective phase II study of bevacizumab with chemoradiation and surgery. As a benchmark, we used data from an analysis of 42 patients with locally advanced rectal cancer treated with a contemporary approach of preoperative fluoropyrimidine-based radiation therapy.

Biomarkers of Antiangiogenic Therapy: How Do We Move From Candidate Biomarkers to Valid Biomarkers?

Abstract: With the increasing use of antiangiogenic agents for the treatment of cancers, establishing biomarkers of response and resistance has become a priority for oncologists and pharmaceutical companies This urgency comes from the need to select the patients most likely to benefit from these high-cost therapies It also stems from the necessity of identifying new targets to prevent the invariable escape from these therapies, which target specifically or primarily the vascular endothelial growth factor (VEGF) pathway But the much needed biomarkers remain elusive One of the reasons is the still unclear mechanism(s) of action of these drugs Blocking VEGF can have antivascular and normalizing effects on the tumor vasculature, which may not necessarily translate into clinical responses as evaluated by criteria based on tumor size measurements such as the Response Evaluation Criteria in Solid Tumors Moreover, excessive antivascular effects (when using high doses) might induce a transient response, but could lead to severe toxicities, as well as to more aggressive tumors, as seen in mouse models Similarly, vascular normalization alone (with no cytotoxic treatment) might not be sufficient to shrink tumors or halt their growth, as demonstrated in mice Finally, some of the actions of antiangiogenic agents could be systemic For example, antiangiogenic agents could affect trafficking and function of hematopoietic progenitor cells and effector immune cells This could result in promotion or delay in tumor growth depending on the hematopoietic cell type involved Given this complexity, it is most likely that for each cancer and each agent, we might need a specific set of biomarkers for good prediction, and that these biomarkers will be mechanism specific Ideally, these biomarkers should be relatively easy to measure by imaging or in bodily fluids using standardized protocols For plasma or serum biomarkers, this could be achieved readily, given the multiple and reliable options to measure various proteins To date, only a few randomized trials have retrospectively integrated circulating biomarker evaluations, and unfortunately, none have yet identified a valid circulating biomarker candidate In non–small-cell lung cancer (NSCLC), the anti-VEGF antibody bevacizumab was shown to be effective when combined with chemotherapy in two randomized phase III trials In a phase II/III study of bevacizumab with chemotherapy in NSCLC patients, a high baseline circulating plasma VEGF level did not predict patient survival, despite correlating with the response evaluated by Response Evaluation Criteria in Solid Tumors Similarly, baseline soluble intracellular adhesion molecule 1 (sICAM1) was an independent prognostic factor of overall survival in patients treated with chemotherapy with chemotherapy alone or with bevacizumab No correlation was seen with other intuitive biomarker candidates, such as basic fibroblast growth factor or sE-Selectin Therefore, identifying biomarker candidates for prospective evaluation in randomized antiangiogenic trials remains an outstanding challenge in NSCLC and other cancers The comprehensive biomarker study by Hanrahan et al published in this issue of Journal of Clinical Oncology is a step in the right direction These investigators explored a set of 35 plasma biomarkers in NSCLC patients at four time-points after antiangiogenic therapy alone with the VEGF receptor 2 tyrosine kinase inhibitor (TKI) vandetanib, chemotherapy alone, or a combination of the two Vandetanib monotherapy transiently increased the levels of circulating interleukin 8 (IL-8; at day 8) and VEGF (at day 43), and decreased the levels of its soluble receptor VEGF receptor 2 (sVEGFR2; at day 43) In contrast, chemotherapy alone did not change circulating VEGF or IL-8, but transiently decreased sVEGFR2, IL–1 receptor antagonist, matrix metalloproteinase 9, and IL-12, and increased monocyte chemotactic protein-1 plasma levels at day 8 Surprisingly, vandetanib with chemotherapy did not significantly change circulating VEGF, sVEGFR2 or IL-8 levels, but transiently decreased IL-12 and matrix metalloproteinase 9, and increased monocyte chemotactic protein-1 in plasma at day 8 Hanrahan et al also explored possible correlations between the changes in these biomarkers after treatment and the outcome in individual patients They report that lower levels of sICAM1 at day 8 after treatment were significantly associated with poorer treatment outcome in the groups of patients who received vandetanib Although exploratory in nature and with a relatively modest sample size, Hanrahan et al report data from a randomized, threearm trial The study has important implications First, it confirms that pursuing mechanistic biomarkers (ie, circulating proteins with known proor antiangiogenic activity) shortly after treatment initiation might be a fruitful approach, as many of the biomarker changes occur rapidly after the onset of therapy Consistent with this, we have shown JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 28 NUMBER 2 JANUARY 1

In vivo validation of MRI vessel caliber index measurement methods with intravital optical microscopy in a U87 mouse brain tumor model

Abstract: The vessel caliber index (VCI), a magnetic resonance imaging biomarker of the average blood vessel diameter, is increasingly being used as a tool for assessing tumor angiogenesis and response to antiangiogenic therapy. However, although the VCI has been correlated with histological vessel diameters, good quantitative agreement with histology has been lacking. In addition, no VCI validation studies have been performed in vivo where the structural deformations frequently associated with histological tissue preparation are not present. This study employs intravital optical microscopy (IVM) measurements of cerebral blood vessel diameters in a mouse orthotopic glioma model to provide the first such in vivo validation. Two VCI correlation models, both a linear and a 3/2-power dependence on the ΔR2*/ΔR2 ratio, were compared with the IVM data. The linear VCI model, determined from steady-state susceptibility contrast (SSC) images, was found to be in excellent quantitative agreement with the intravitally determined VCI for separate tumor size matched groups of mice. In addition, preliminary data indicate that the VCI is independent of whether a dynamic susceptibility contrast or SSC measurement method is used.

The Ontario Osteoporosis Strategy: implementation of a population-based osteoporosis action plan in Canada

Abstract: In the last decade, there have been a number of action plans published to highlight the importance of preventing osteoporosis and related fractures. In the province of Ontario Canada, the Ministry of Health provided funding for the Ontario Osteoporosis Strategy. The goal is to reduce morbidity, mortality, and costs from osteoporosis and related fractures through an integrated and comprehensive approach aimed at health promotion and disease management. This paper describes the components of the Ontario Osteoporosis Strategy and progress on implementation efforts as of March 2009. There are five main components: health promotion; bone mineral density testing, access, and quality; postfracture care; professional education; and research and evaluation. Responsibility for implementation of the initiatives within the components is shared across a number of professional and patient organizations and academic teaching hospitals with osteoporosis researchers. The lessons learned from each phase of the development, implementation, and evaluation of the Ontario Osteoporosis Strategy provides a tremendous opportunity to inform other jurisdictions embarking on implementing similar large-scale bone health initiatives.