An integrated approach to the prediction of chemotherapeutic response in patients with breast cancer.

BACKGROUND: A major challenge in oncology is the selection of the most effective chemotherapeutic agents for individual patients, while the administration of ineffective chemotherapy increases mortality and decreases quality of life in cancer patients. This emphasizes the need to evaluate every patient's probability of responding to each chemotherapeutic agent and limiting the agents used to those most likely to be effective. METHODS AND RESULTS: Using gene expression data on the NCI-60 and corresponding drug sensitivity, mRNA and microRNA profiles were developed representing sensitivity to individual chemotherapeutic agents. The mRNA signatures were tested in an independent cohort of 133 breast cancer patients treated with the TFAC (paclitaxel, 5-fluorouracil, adriamycin, and cyclophosphamide) chemotherapy regimen. To further dissect the biology of resistance, we applied signatures of oncogenic pathway activation and performed hierarchical clustering. We then used mRNA signatures of chemotherapy sensitivity to identify alternative therapeutics for patients resistant to TFAC. Profiles from mRNA and microRNA expression data represent distinct biologic mechanisms of resistance to common cytotoxic agents. The individual mRNA signatures were validated in an independent dataset of breast tumors (P = 0.002, NPV = 82%). When the accuracy of the signatures was analyzed based on molecular variables, the predictive ability was found to be greater in basal-like than non basal-like patients (P = 0.03 and P = 0.06). Samples from patients with co-activated Myc and E2F represented the cohort with the lowest percentage (8%) of responders. Using mRNA signatures of sensitivity to other cytotoxic agents, we predict that TFAC non-responders are more likely to be sensitive to docetaxel (P = 0.04), representing a viable alternative therapy. CONCLUSIONS: Our results suggest that the optimal strategy for chemotherapy sensitivity prediction integrates molecular variables such as ER and HER2 status with corresponding microRNA and mRNA expression profiles. Importantly, we also present evidence to support the concept that analysis of molecular variables can present a rational strategy to identifying alternative therapeutic opportunities.

High-throughput identification of chemical inhibitors of E. coli Group 2 capsule biogenesis as anti-virulence agents.

Rising antibiotic resistance among Escherichia coli, the leading cause of urinary tract infections (UTIs), has placed a new focus on molecular pathogenesis studies, aiming to identify new therapeutic targets. Anti-virulence agents are attractive as chemotherapeutics to attenuate an organism during disease but not necessarily during benign commensalism, thus decreasing the stress on beneficial microbial communities and lessening the emergence of resistance. We and others have demonstrated that the K antigen capsule of E. coli is a preeminent virulence determinant during UTI and more invasive diseases. Components of assembly and export are highly conserved among the major K antigen capsular types associated with UTI-causing E. coli and are distinct from the capsule biogenesis machinery of many commensal E. coli, making these attractive therapeutic targets. We conducted a screen for anti-capsular small molecules and identified an agent designated "C7" that blocks the production of K1 and K5 capsules, unrelated polysaccharide types among the Group 2-3 capsules. Herein lies proof-of-concept that this screen may be implemented with larger chemical libraries to identify second-generation small-molecule inhibitors of capsule biogenesis. These inhibitors will lead to a better understanding of capsule biogenesis and may represent a new class of therapeutics.

A PK2/Bv8/PROK2 antagonist suppresses tumorigenic processes by inhibiting angiogenesis in glioma and blocking myeloid cell infiltration in pancreatic cancer.

Infiltration of myeloid cells in the tumor microenvironment is often associated with enhanced angiogenesis and tumor progression, resulting in poor prognosis in many types of cancer. The polypeptide chemokine PK2 (Bv8, PROK2) has been shown to regulate myeloid cell mobilization from the bone marrow, leading to activation of the angiogenic process, as well as accumulation of macrophages and neutrophils in the tumor site. Neutralizing antibodies against PK2 were shown to display potent anti-tumor efficacy, illustrating the potential of PK2-antagonists as therapeutic agents for the treatment of cancer. In this study we demonstrate the anti-tumor activity of a small molecule PK2 antagonist, PKRA7, in the context of glioblastoma and pancreatic cancer xenograft tumor models. For the highly vascularized glioblastoma, PKRA7 was associated with decreased blood vessel density and increased necrotic areas in the tumor mass. Consistent with the anti-angiogenic activity of PKRA7 in vivo, this compound effectively reduced PK2-induced microvascular endothelial cell branching in vitro. For the poorly vascularized pancreatic cancer, the primary anti-tumor effect of PKRA7 appears to be mediated by the blockage of myeloid cell migration/infiltration. At the molecular level, PKRA7 inhibits PK2-induced expression of certain pro-migratory chemokines and chemokine receptors in macrophages. Combining PKRA7 treatment with standard chemotherapeutic agents resulted in enhanced effects in xenograft models for both types of tumor. Taken together, our results indicate that the anti-tumor activity of PKRA7 can be mediated by two distinct mechanisms that are relevant to the pathological features of the specific type of cancer. This small molecule PK2 antagonist holds the promise to be further developed as an effective agent for combinational cancer therapy.

Experimental evaluation of evolution and coevolution as agents of ecosystem change in Trinidadian streams.

Evolution has been shown to be a critical determinant of ecological processes in some systems, but its importance relative to traditional ecological effects is not well known. In addition, almost nothing is known about the role of coevolution in shaping ecosystem function. Here, we experimentally evaluated the relative effects of species invasion (a traditional ecological effect), evolution and coevolution on ecosystem processes in Trinidadian streams. We manipulated the presence and population-of-origin of two common fish species, the guppy (Poecilia reticulata) and the killifish (Rivulus hartii). We measured epilithic algal biomass and accrual, aquatic invertebrate biomass, and detrital decomposition. Our results show that, for some ecosystem responses, the effects of evolution and coevolution were larger than the effects of species invasion. Guppy evolution in response to alternative predation regimes significantly influenced algal biomass and accrual rates. Guppies from a high-predation site caused an increase in algae relative to guppies from a low-predation site; algae effects were probably shaped by observed divergence in rates of nutrient excretion and algae consumption. Rivulus-guppy coevolution significantly influenced the biomass of aquatic invertebrates. Locally coevolved populations reduced invertebrate biomass relative to non-coevolved populations. These results challenge the general assumption that intraspecific diversity is a less critical determinant of ecosystem function than is interspecific diversity. Given existing evidence for contemporary evolution in these fish species, our findings suggest considerable potential for eco-evolutionary feedbacks to operate as populations adapt to natural or anthropogenic perturbations.

Diasporic Agents and Trans-Asian Flows in the Making of Asian Modernity: The Case of Thailand

How do our everyday actions shape and transform the world economy? This volume of original essays argues that current scholarship in international political economy (IPE) is too highly focused on powerful states and large international institutions. The contributors examine specific forms of â everyday' actions to demonstrate how small-scale actors and their decisions can shape the global economy. They analyse a range of seemingly ordinary or subordinate actors, including peasants, working classes and trade unions, lower-middle and middle classes, female migrant labourers and Eastern diasporas, and examine how they have agency in transforming their political and economic environments. This book offers a novel way of thinking about everyday forms of change across a range of topical issues including globalisation, international finance, trade, taxation, consumerism, labour rights and regimes. It will appeal to students and scholars of politics, international relations, political economy and sociology.

Copper signaling axis as a target for prostate cancer therapeutics.

Previously published reports indicate that serum copper levels are elevated in patients with prostate cancer and that increased copper uptake can be used as a means to image prostate tumors. It is unclear, however, to what extent copper is required for prostate cancer cell function as we observed only modest effects of chelation strategies on the growth of these cells in vitro. With the goal of exploiting prostate cancer cell proclivity for copper uptake, we developed a "conditional lethal" screen to identify compounds whose cytotoxic actions were manifested in a copper-dependent manner. Emerging from this screen was a series of dithiocarbamates, which, when complexed with copper, induced reactive oxygen species-dependent apoptosis of malignant, but not normal, prostate cells. One of the dithiocarbamates identified, disulfiram (DSF), is an FDA-approved drug that has previously yielded disappointing results in clinical trials in patients with recurrent prostate cancer. Similarly, in our studies, DSF alone had a minimal effect on the growth of prostate cancer tumors when propagated as xenografts. However, when DSF was coadministered with copper, a very dramatic inhibition of tumor growth in models of hormone-sensitive and of castrate-resistant disease was observed. Furthermore, we determined that prostate cancer cells express high levels of CTR1, the primary copper transporter, and additional chaperones that are required to maintain intracellular copper homeostasis. The expression levels of most of these proteins are increased further upon treatment of androgen receptor (AR)-positive prostate cancer cell lines with androgens. Not surprisingly, robust CTR1-dependent uptake of copper into prostate cancer cells was observed, an activity that was accentuated by activation of AR. Given these data linking AR to intracellular copper uptake, we believe that dithiocarbamate/copper complexes are likely to be effective for the treatment of patients with prostate cancer whose disease is resistant to classical androgen ablation therapies.

D-Amino acid peptide residualizing agents bearing N-hydroxysuccinimido- and maleimido-functional groups and their application for trastuzumab radioiodination.

INTRODUCTION: Proteins that undergo receptor-mediated endocytosis are subject to lysosomal degradation, requiring radioiodination methods that minimize loss of radioactivity from tumor cells after this process occurs. To accomplish this, we developed the residualizing radioiodination agent N(ϵ)-(3-[(*)I]iodobenzoyl)-Lys(5)-N(α)-maleimido-Gly(1)-D-GEEEK (Mal-D-GEEEK-[(*)I]IB), which enhanced tumor uptake but also increased kidney activity and necessitates generation of sulfhydryl moieties on the protein. The purpose of the current study was to synthesize and evaluate a new D-amino acid based agent that might avoid these potential problems. METHODS: N(α)-(3-iodobenzoyl)-(5-succinimidyloxycarbonyl)-D-EEEG (NHS-IB-D-EEEG), which contains 3 D-glutamates to provide negative charge and a N-hydroxysuccinimide function to permit conjugation to unmodified proteins, and the corresponding tin precursor were produced by solid phase peptide synthesis and subsequent conjugation with appropriate reagents. Radioiodination of the anti-HER2 antibody trastuzumab using NHS-IB-D-EEEG and Mal-D-GEEEK-IB was compared. Paired-label internalization assays on BT474 breast carcinoma cells and biodistribution studies in athymic mice bearing BT474M1 xenografts were performed to evaluate the two radioiodinated D-peptide trastuzumab conjugates. RESULTS: NHS-[(131)I]IB-D-EEEG was produced in 53.8%±13.4% and conjugated to trastuzumab in 39.5%±7.6% yield. Paired-label internalization assays with trastuzumab-NHS-[(131)I]IB-D-EEEG and trastuzumab-Mal-D-GEEEK-[(125)I]IB demonstrated similar intracellular trapping for both conjugates at 1h ((131)I, 84.4%±6.1%; (125)I, 88.6%±5.2%) through 24h ((131)I, 60.7%±6.8%; (125)I, 64.9%±6.9%). In the biodistribution experiment, tumor uptake peaked at 48 h (trastuzumab-NHS-[(131)I]IB-D-EEEG, 29.8%±3.6%ID/g; trastuzumab-Mal-D-GEEEK-[(125)I]IB, 45.3%±5.3%ID/g) and was significantly higher for (125)I at all time points. In general, normal tissue levels were lower for trastuzumab-NHS-[(131)I]IB-D-EEEG, with the differences being greatest in kidneys ((131)I, 2.2%±0.4%ID/g; (125)I, 16.9%±2.8%ID/g at 144 h). CONCLUSION: NHS-[(131)I]IB-D-EEEG warrants further evaluation as a residualizing radioiodination agent for labeling internalizing antibodies/fragments, particularly for applications where excessive renal accumulation could be problematic.

In vivo small animal micro-CT using nanoparticle contrast agents.

Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research.

Photophysique et photochimie de complexes mono- et bifonctionnels du ruthénium (II), photosondes de l'adn et agents inhibiteurs de la transcription

Doctorat en Sciences

A phase 1-2 clinical trial of gene therapy for recurrent glioblastoma multiforme by tumor transduction with the herpes simplex thymidine kinase gene followed by ganciclovir.

This study has investigated the effects of herpes simplex thymidine kinase gene (HSV-tk) transfer followed by ganciclovir treatment as adjuvant gene therapy to surgical resection in patients with recurrent glioblastoma multiforme (GBM). The study was open and single-arm, and aimed at assessing the feasibility and safety of the technique and indications of antitumor activity. In 48 patients a suspension of retroviral vector-producing cells (VPCs) was administered by intracerebral injection immediately after tumor resection. Intravenous ganciclovir was infused daily 14 to 27 days after surgery. Patients were monitored for adverse events and for life by regular biosafety assaying. Tumor changes were monitored by magnetic resonance imaging (MRI). Reflux during injection was a frequent occurrence but serious adverse events during the treatment period (days 1-27) were few and of a nature not unexpected in this population. One patient experienced transient neurological disorders associated with postganciclovir MRI enhancement. There was no evidence of replication-competent retrovirus in peripheral blood leukocytes or in tissue samples of reresection or autopsy. Vector DNA was shown in the leukocytes of some patients but not in autopsy gonadal samples. The median survival time was 8.6 months, and the 12-month survival rate was 13 of 48 (27%). On MRI studies, tumor recurrence was absent in seven patients for at least 6 months and for at least 12 months in two patients, one of whom remains recurrence free at more than 24 months. Treatment-characteristic images of injection tracks and intracavity hemoglobin were apparent. In conclusion, the gene therapy is feasible and appears to be satisfactorily safe as an adjuvant to the surgical resection of recurrent GBM, but any benefit appears to be marginal. Investigation of the precise effectiveness of this gene therapy requires prospective, controlled studies.

A dose-finding study of lanreotide (a somatostatin analog) in patients with colorectal carcinoma

BACKGROUND. Laboratory data suggest that insulin-like growth factor-1 (IGE-1) may stimulate the growth of different human tumors. At least in acromegalic patients, somatostatin (SMS) analogs, such as lanreotide, suppress the serum levels of growth hormone (GH) and IGE-1. METHODS. To evaluate the tolerability and biologic activity of different doses of lanreotide in patients with advanced colorectal carcinoma, consecutive groups of 3 patients each were subcutaneous treated with lanreotide at doses of 1, 2, 3, 4, 5, or 6 mg three times a day for 2 months. In the event of Grade 3 side effects, 3 additional patients were treated with the same dose before the next dose escalation. Serum samples were obtained on Days 0, 15, 30, and 60 for serum GH, IGF-1, and lanreotide assessment. RESULTS. Twenty-four patients were enrolled and all were evaluable. Except for the 3 and 6 mg doses, for which the observation of a Grade 3 side effect required that an additional three patients be treated, it was sufficient to treat 3 patients at each dose. The overall incidence of side effects was as follows: changes in bowel habits, 83%; abdominal cramps, 79%; diarrhea, 17%; vomiting, 17%; nausea, 21%; steatorrhea, 78%; hyperglycemia, 35%; laboratory hypothyroidism, 39%; gallstones, 13%; and weight loss, 17%. No evidence of an increase in the incidence, intensity, or duration of side effects was observed with dose escalation. Serum IGF-1 levels were as follows: Day 13: 63%, 60%, and 67% of the baseline values for the low (12 mg), intermediate (3-4 mg), and high (5- 6 mg) dose groups, respectively; Day 30: 63%, 59%, and 51%, respectively; and Day 60: 73%, 69%, and 47%, respectively. Serum lanreotide levels declined during treatment in all of the dose groups (90 ng/mL on Day 15, and 35 ng/mL on Day 60 for the 5-6 mg group; 10 ng/mL on Day 15, and 1.5 ng/mL on Day 60 for the 1-2 mg group). No antitumor activity or tumor marker reduction was observed. CONCLUSIONS. No increase in toxicity was observed when subcutaneous lanreotide doses were escalated to 6 mg three times a day for 2 months. The highest doses seemed to maintain reduced serum IGF-1 levels; with the lowest doses, a 'rebound' in serum IGF-1 levels was observed during treatment. Nevertheless, intermittent subcutaneous injections do not ensure constant serum drug concentrations over time.