Mark Pagel, PhD - US grants

A new hypothesis has been proposed for the function of conspicuous sexual traits in female primates. The conventional view has been that certain female traits that occur in sexual contexts, such as sexual skin swellings, are designed to attract the attention of or incite competition between males in multi-male species. However, this view does not explain why females in these species would need to advertise their reproductive state so conspicuously or why conspicuous traits would incite more competition among males than would otherwise occur. In contrast, Pagel argues that conspicuous sexual males because they advertise the female's quality or condition. The signals evolve in response to male mate choice and competition among females to attract males (the mirror image of what has been normally accepted). While the female competition hypothesis is the most developed hypothesis to date for the function of conspicuous sexual advertisement in female primates, no tests have been made of its predictions. This dissertation project will examine variation in female sexual traits and their influence on female attractiveness to males in wild olive baboons at Gombe national Park in Tanzania. No study to date has been designed to test the hypothesis that male sexual interest is influenced by variation in any of these female traits in the wild, although it has been apparent that males mate selectively. This study will make a substantial first step towards understanding the evolutionary and social significance of female sexual signals and sexual attractiveness, a topic clearly of vital importance for understanding human evolution. It will also result in the training of young experts in the area of social behavior.

DESCRIPTION (provided by applicant): Proteases are important biomarkers for many pathologies and biological processes and are often targets of chemotherapeutics. Magnetic Resonance Imaging (MRI) is an outstanding diagnostic tool for identifying suspicious lesions, but suffers from many false-positive results due to a lack of specificity for pathological tissues versus normal tissues. The development of MRI contrast agents that can detect protease biomarkers of metastatic tumors or the response to anti-tumor therapies would greatly improve the specificity of MRI for detecting and evaluating cancer. We have developed a fundamentally new type of protease-responsive MRI contrast agent that is detected through PARAmagnetic Chemical Exchange Saturation Transfer (PARACEST). This mechanism allows each PARACEST contrast agent to be selectively detected, so that multiple PARACEST contrast agents may be simultaneously detected during a single MRI scan session, such as a protease-unresponsive PARACEST contrast agent that can serve as a `control'to account for the pharmacokinetics of the agents. Furthermore, we are the first research team to demonstrate the detection of PARACEST contrast agents within in vivo animal models. We will combine our accomplishments with PARACEST contrast agents to detect multiple enzyme-responsive PARACEST contrast agents within in vivo animal models. More specifically, we will design and apply PARACEST contrast agents to detect caspase-3 during TRAIL-induced tumor cell apoptosis in an in vivo mouse model of MCF-7c3 human mammary carcinoma. We will also design and apply PARACEST contrast agents to simultaneously detect cathepsin B and urokinase Plasminogen Activator in an in vivo mouse model of MCF-7 and MBA-MB-231 mammary carcinoma. The successful achievement of our specific aims will result in new platform technology that can be immediately used during many pre-clinical studies, and that can be used as a foundation for further studies to gain clinical approval for this new type of diagnostic molecular imaging agent to detect protease biomarkers in cancer and other pathological tissues. Narrative: A fundamentally new type of protease-responsive MRI contrast agent has been developed that is detected through PARAmagnetic Chemical Exchange Saturation Transfer (PARACEST). Furthermore, PARACEST contrast agents can be detected within in vivo animal models. This research application will combine these accomplishments with PARACEST contrast agents to detect multiple enzyme-responsive PARACEST contrast agents within in vivo animal models.

0958790
Romanowski

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."

This proposal describes acquisition of a broadly tunable femtosecond laser system, which includes an optical parametric oscillator pumped by a titanium-sapphire laser and associated instrumentation. It will enable a broad range of experimental work on the interface of nanotechnology, materials sciences and medicine. This highly advanced instrumentation is prohibitively expensive to be acquired through individual research funding. The requested instrument will be installed in a novel type of a laser beam facility, which will provide open access to the laser beam, and room for multiple experimental installations as required by researchers sharing the research focus on optical spectroscopy and imaging. Research in many areas of chemistry, materials sciences, biology and medicine relies on using light for probing structure and function of individual molecules, their assemblies, and living systems. Increasingly important is understanding of photophysics and photochemistry at the time scale as short as femtoseconds, and in the broad spectral range spanning ultraviolet, visible and near infrared. The shared laser facility is requested by a core user base representing a broad range of research expertise and active projects. When installed, it will accelerate the pace of research in medical diagnosis and intervention, analytical methods for bio-threat agents, solar energy harvesting and conversion, and basic sciences.

DESCRIPTION (provided by applicant): Enzyme activities are important biomarkers for cancer diagnoses and assessing chemotherapies. We have developed MRI contrast agents that are detected via Chemical Exchange Saturation Transfer (CEST) and that are responsive to enzyme activity. We have also developed CEST MRI methods that can detect these agents within in vivo tumor tissues in mouse models of human cancers. Importantly, we can selectively detect an enzyme-responsive agent and an unresponsive control agent during the same study in the same tissue location, which improves our evaluation of enzyme activity within the mouse model. Just as multiple fluorophores have revolutionized the evaluation of enzyme activities during in vitro and ex vivo studies, CEST agents and CEST MRI has potential to revolutionize the evaluation of enzyme activities in vivo. We propose to build on our recent research successes by linking enzyme-responsive and control agents to create a dimeric agent, by comparing paramagnetic and diamagnetic CEST agents, and by optimizing the saturation period of the CEST MRI acquisition protocol in order to improve the detection sensitivity of CEST MRI. We also propose to develop enzyme-responsive CEST agents that semi-quantitatively detect the activities of urokinase Plasminogen Activator (uPA) in mouse models of pancreatic cancer, Prostate Specific Membrane Antigen (PSMA) in mouse models of prostate cancer, and transglutaminase (TG2) in mouse models of breast cancer. We propose to use these CEST agents and our in vivo CEST MRI methodology to investigate three biomedical aims: A) to predict the effect of chemotherapies before they are administered to mouse models; B) to evaluate early response to chemotherapies; C) to investigate our hypothesis that enzyme activity is a more accurate biomarker than enzyme expression for predicting and evaluating therapeutic effects. Together, these studies address our overarching goal of eventually using CEST agents and CEST MRI to tailor the choice of chemotherapy and treatment regimen for each individual patient, in order to support the paradigm of personalized medicine. PUBLIC HEALTH RELEVANCE: We propose to continue to develop CEST agents and CEST MRI methods that detect enzyme activities within in vivo mouse models of cancer. We propose to use our CEST agents and CEST MRI methods to evaluate chemotherapies and to assess whether enzyme activity is a better biomarker than enzyme expression.

DESCRIPTION (provided by applicant): This proposal will continue the development of an innovative MRI method that can measure the extracellular pH (pHe) of the tumor microenvironment. Our MRI method uses Chemical Exchange Saturation Transfer (CEST) agents that accurately and precisely measure pH. We have used our CEST agents and CEST MRI methods to map tumor pHe in mouse tumor models. We propose to improve the detection sensitivity of CEST MRI to facilitate our pre-clinical studies eventual clinical translation. Our research has strong impact because tumor pHe measurements may be used to predict the effects of weak-base and weak-acid chemotherapies before they are administered to a patient. Tumor pHe measurements may also be used to monitor alkalinizing therapies that can increase survival and decrease metastasis. We propose to establish that our CEST MRI method can measure tumor pHe with sufficient accuracy and precision to impact the choice of cancer therapies. ¿ Specific Aim 1: To improve the detection sensitivity of CEST MRI methods and CEST agents that measure tumor pHe. We will optimize the saturation period of the CEST MRI pulse sequence, and improve our paramagnetic CEST agents to have larger chemical shifts. ¿ Specific Aim 2: To monitor the effect of alkalinizing therapy using tumor pHe measurements. We hypothesize that monitoring pHe can be used to optimize the dose of an alkalinizing therapy to raise tumor pHe without affecting kidney pHe. ¿ Specific Aim 3: To quantitatively predict chemotherapeutic effects with tumor pHe measurements. We hypothesize that a single tumor pHe measurement before initiating chemotherapy can quantitatively predict the therapeutic effect on tumor growth. Our deliverable is a clinically-translatable imaging method that can profoundly impact personalized medicine. By quantitatively measuring the acidity of a solid tumor, a physician may then select the weak-base or weak- acid chemotherapy that should have a better therapeutic effect for that individual patient. By monitoring the pHe of the tumor and kidney, a physician may adjust an alkalinizing treatment dosage to provide an optimal therapeutic effect for an individual patient. Although our research focuses on breast cancer, our methodology can impact personalized medicine for many other cancers and other pathologies. PUBLIC HEALTH RELEVANCE: This research project will refine CEST agents and CEST MRI methods that measure extracellular pH (pHe) in pre-clinical tumor models. These methods will be used to optimize the dose of an alkalinizing therapy and to predict the efficacy of weak-base and weak-acid chemotehrapies.

This research plan will continue our development of Chemical Exchange Saturation Transfer (CEST) MRI acquisition and analysis methods for imaging patients with cancer. AcidoCEST MRI with an exogenous contrast agent is an innovative variation of this technique that measures extracellular pH in solid tumors. We have also developed an exceptionally innovative method that acquires endogenous CEST MR images with multiple powers, which can measure the chemical exchange rate of endogenous proteins that can assess relative differences in pH. We will improve our CEST MRI acquisition methods by accelerating the imaging speed, reducing and eliminating complications due to patient motion, eliminating complications caused by fat signal, and expanding to 3D imaging methods. We will also improve image analysis methods that are required for CEST contrast from endogenous proteins and exogenous contrast agents. Our research has strong impact because acidoCEST MRI can track changes in tumor acidosis in response to chemotherapy and chemoradiation therapy in patients who have breast cancer and head & neck cancer. Endogenous CEST MRI can improve the diagnoses of brain tumor recurrence vs. pseudoprogression, and evaluations of lung cancer vs. lung infection. We will perform clinical studies with our endogenous and exogenous CEST MRI methods to image patients with brain, breast, lung, and head & neck cancers. To amplify the impact of our research, we will develop versions of our CEST MRI acquisition methods for the many versions of the 13 Siemens hardware platforms and software operating systems at the MD Anderson Cancer Center. We will also develop user-friendly CEST analysis methods for many researchers at MD Anderson. We will leverage our unique research environment and expertise with intra-institutional dissemination to provide inter-institutional dissemination, by sharing share these acquisition and analysis tools with other CEST MRI researchers. We will collaborate with NIST to provide the first CEST MRI phantom that can standardize the development and implementation of intra- and inter-institutional CEST MRI methods. Our team of outstanding investigators includes experts in CEST saturation methods, CEST MR image analysis, clinical contrast agents, rapid MRI acquisition methods, high field 7T MRI, clinical radiology, biostatistics, histopathology and oncology. Based on our expertise and years of productivity in clinical CEST MRI, we have developed an exceptional research approach. As the world's largest cancer center and a health destination, the MD Anderson Cancer Center has the patient population that provides very strong institutional support for our clinical studies.

Our goal is to quantitatively measure extracellular pH (pHe) in the tumor microenvironment to assess tumor acidosis. These assessments can be used to improve evaluations of solid tumors, to aid in predicting the response to immunotherapy before the treatment is initiated, and to evaluate the early response of tumors to many types of drug treatment. These multiple applications can provide strong impact for studies of mouse tumor models, and eventually for patients who have solid tumors. To meet this goal, we propose to develop PET/MRI contrast agents that can quantitatively measure pHe, and apply these agents during simultaneous PET/MRI studies in mouse models of human cancers. Dynamic changes in the relaxation-based MR image contrast are sensitive to tumor pHe as well as the concentration of the agent in tumor tissue, while the PET image can be used to measure the concentration of the agent in the tumor. Therefore, the PET results can be used to account for the effect of concentration on MR image contrast, which can improve the quantitative measurement of tumor pHe. To overcome the difference in detection sensitivities of PET and MRI, we will co-inject 0.01% ?hot? radiolabeled agent and 99.99% ?cold? MRI contrast agent. Notably, this approach would fail to image cell receptors or intracellular biomarkers, but is ideally suited to interrogate the extracellular tumor microenvironment. In particular, these agents are designed to have the same pharmacokinetic delivery to the extracellular tumor microenvironment during the first 10 minutes after co- injection, so that the MBq radioactivity measurement with PET can be used to evaluate the ?M concentration of the MRI contrast agent. Therefore, our development of contrast agents for simultaneous PET/MRI has strong innovation for cancer imaging. Accurate and precise measurements of tumor pHe requires great attention to rigor, especially to address potential inaccuracies and imprecisions with both imaging modalities. Therefore, we have designed a strong research approach with careful attention to rigor. We have assembled a team of strong investigators who have extensive experience in developing ?smart? MRI contrast agents and PET tracers, and performing molecular imaging studies with small animal tumor models especially for imaging tumor acidosis. We have recently obtained one of the few commercial PET/MRI systems for small animal imaging world-wide, and MD Anderson has an extensive infrastructure for radiochemistry and small animal imaging, which attests to our strong environment. Our deliverable is a fundamentally new class of contrast agents for molecular imaging with PET/MRI. As a longer term goal, our PET/MRI contrast agents have outstanding potential for clinical translation, which will provide a transformative ?game changing technology? for clinical PET/MRI.

Our goal is to improve the localization of solid tumors that express and secrete high levels of protease enzymes. Proteases degrade the extracellular matrix and cellular stroma, increasing tumor proliferation, invasion, and metastasis. Our research will focus on the detection of tumors with cathepsin B and urokinase Plasminogen Activator, which are protease biomarkers of malignant tumors. Yet our technology can detect many types of proteases, and therefore can be a flexible platform technology for detecting many types of tumors. To meet our goal, we propose to develop a new type of contrast agent that is cleaved by a protease, then undergoes spontaneous disassembly, and finally spontaneously forms eumelanin or pheomelanin. Our contrast agents consist of peptides and melanins that are natural, biocompatible materials. Our spontaneous disassembling linkers are used for drug delivery, so that these linkers are also biocompatible. Therefore, our contrast agents have strong potential for eventual clinical translation. We propose to use our melanin-generating contrast agents to improve tumor localization with noninvasive Multispectral Optoacoustic Tomography (MSOT), also known as photoacoustic imaging. Pre-clinical MSOT can image an entire torso of mouse tumor models, and clinical MSOT has been used to image many tumor types including breast cancer. We will develop and use an innovative dynamic MSOT imaging protocol that will monitor the generation of melanins in tumors, which improves the specificity of protease-active tumors vs. normal tissues. We also propose to use our melanin-generating contrast agents to improve tumor localization during surgery. Other research has developed fluorescent contrast agents that are trapped or activated in tumors with high protease activity. These tumors can then be visualized during surgery, when the tumors can be imaged with fluorescence imaging instrumentation. Our technology will cause melanins to accumulate in tumors with high protease activity, causing the tumors to become black. Simple visual inspection, without expensive and cumbersome fluorescence imaging instrumentation, can identify the black tumors against the beige-to-red background of normal tissues. These black tumors can then be excised from the body during surgery. As a longer-term goal, we propose that MSOT could eventually be used to localize protease-active tumors as deep as 3 cm from tissue surfaces that are exposed during surgery, further improving surgical resection of tumors. To meet our objectives, we will synthesize each contrast agent, demonstrate that cleavage with a specific enzyme results in synthesis of a melanin, and perform Michaelis-Menten enzyme kinetics studies to validate the detection of enzyme activity. For Aim 1, we will perform in vivo MSOT studies to detect protease activities in mouse models of human tumors. For Aim 2, we will simulate optical guided surgery with mouse tumor models to detect black tumors that have high melanin accumulation. Our deliverable is a foundation for pursuing clinical translation of our contrast agents for clinical MSOT exams and during clinical surgery.