Fifth Round

(Abstracts provided by applicants)

Development of a New Antiangiogenic Tumor Blocker SBD 1
Krzysztof Bojanowski, Principal Investigator Sunny BioDiscovery, Inc., Oakland, CA	R43 CA 96058-01
Inhibition of tumor angiogenesis-the growth of new blood vessels towards the tumor mass-is a new and promising approach to anti-cancer therapy. The results of Phase I/II clinical trials completed so far with several angiogenesis inhibitors validate the concept of tumor angiogenesis as effective target for anti-cancer therapy. However, the same studies stress the need for novel, more potent angiogenesis inhibitors. We addressed this need by isolating the human urine a new protein (SBD.1), which specifically blocks the proliferation of capillary endothelial cells in vitro (ID50=15NG/ML), angiogenesis in chorioallentoic membrane assay, and two growth in vivo (Lewis Lung Carcinoma, T/C=0.04 at 20umum/kg/day), placing SBD.1 among the most potent known angiogenesis inhibitors. Sequencing of SBD/1 showed it is a novel protein and its mild proteolysis resulted in the generation of smaller peptides without losing the inhibitory activity. Here, we propose to a) clone and express SBD.1 in a recombinant system; b) isolate and sequence the activity SBD.1 fragments; c) test the purified SBD.1 on prostate, lung and breast carcinoma human xenografts in nude mice to further assess its anti-tumor activity This project will result in the cloning of a novel therapeutically-active protein, which may be an important endogenous regulator of angio- and tumorigenesis in humans. PROPOSED COMMERCIAL APPLICATIONS: The development of SBD.1 addresses a pressing need in the pharmaceutical industry for a new, better angiogenesis inhibitor. Currently targeting anti-cancer therapy, the use of SBD.1 might be later extended to the treatment of vascular pathologies, such as macular degeneration and certain cardiovascular diseases. Meanwhile, SBD.1 can also be commercialized as reagent for laboratory research on angiogenesis. Taken together, these applications represent a substantial potential market for SBD.1

Developing Ligand/Receptor Systems with Infinite Affinity
A.J. Chmura, Principal Investigator1 Lexrite Labs., Dixon, CA	R43 CA 96084-01
Developing technology to target therapeutic agents to cancer cells, while sparing normal cells, is a promising approach to improved treatment. The specific targeting reagents of choice are monoclonal antibodies and their derivatives. Currently there is a good selection of such molecules that bind to highly expressed tumor antigens. The anticancer antibodies Rituxan and Herceptin have been approved by the FDA for use as therapeutic drugs, and several more antibody-based drugs are expected to be approved soon. The binding affinities of many antibodies to characteristic cancer antigens are strikingly low; they depend on multivalent binding for their practical utility. For this reason, the utility of engineered proteins with single binding sites-such as single chain Fv molecules or Fab fragments-is limited. The use of modern combinatorial genetic techniques has led to improvements in the antigen-binding properties of engineered proteins, but further advances are needed. We propose a combined genetic/chemical approach to radically improve one such ligand/receptor interaction to the point of specific, irreversible binding. This research will ultimately lead to products that are themselves therapeutic drugs, or that serve as the first step in targeting drugs, radionuclides, or other effectors, to sites of disease. PROPOSED COMMERCIAL APPLICATION: Target-selective, irreversibly bindig platform for drug delivery, suitable for use in targeted therapy, radiotherapy, prodrug delivery, and other applications where long-lived specific binding is preferred.

Improving the Activation of CPT-11 by hCE-2
Aldis Darzins, Principal Investigator Enchira Biotechnology Corp., Woodlands, TX	R43 CA 96076-01
Selective delivery of drugs to tumors continues to be a major goal in cancer chemotherapy. Pro-drugs activated by enzymes positioned at tumor sites either through ADEPT or GDEPT approaches offer great promise for enhancing the selectivity of cancer therapy. One such promising candidate is CPT-11 (irinotecan), a clinically approved cancer pro-drug, which is converted to the active form SN-38 by the major human liver carboxylesterase hCE-2. However, the inefficient conversion of CPT-11 by hCE-2 limits its development as the enzymatic component of an ADEPT-GDEPT strategy. Therefore, the primary objective of this study will be to evolve, through a variety of molecular techniques, a human CE-2 enzyme with significantly improved catalytic efficiency towards the pro-drug CPT-11. The aims of this proposal are to generate diverse hCE-2 gene libraries, identify improved variants by employing high-throughput screening and perform biochemical/kinetic analyses on the improved enzymes. It is anticipated that the engineering of a highly evolved, human carboxylesterase will be of immense benefit clinically by maximizing the exposure of tumor cells to the cytotoxic agent, potentially limiting the systemic concentrations and reducing the toxicity associated with conventional CPT-11 therapy as well as circumventing potential problems associated with immunogenicity, particularly when used in an ADEPT therapeutic strategy. PROPOSED COMMERCIAL APPLICATIONS: Site-selective CPT-11 activation using an evolved human carboxylesterase conjugated to a monoclonal antibody directed against tumor-specific antigens or delivered by gene therapy formulations will lead to higher SN-38 levels than could be achieved through conventional CPT-11 therapy. This will result in a better therapeutic efficacy at well tolerated doses.

Human Anti-PSMA Antibodies for Prostate Cancer Therapy
Gerald Donovan, Principal Investigator Progenics Pharmaceuticals, Inc., Tarrytown, NY	R43 CA 96075-01
Prostate cancer is the second leading cause of cancer death in American males. Although androgen therapy can temporarily control metastatic disease, most tumors become hormone refractory and then rapidly progress since there is no other effective therapy. Thus, there is an urgent need for new therapies. Prostate-specific membrane antigen (PSMA) is a well-characterized glycoprotein whose expression is largely restricted to epithelial cells. In normal tissues, PSMA exists as a splice variant that lacks the transmembrane domain and is thereby retained in the cytoplasm. But on tumor cells, PSMA contains a single transmembrane domain and a large extracellular domain. This cell-type specificity makes the large extracellular domain of PSMA an ideal candidate for immunotherapy. We propose development of fully human anti-PSMA monoclonal antibodies for the treatment of prostate cancer. Using Xenomice that are transgenic for the human immunoglobulin gone locus and proven immunization/screening strategies, we will generate a panel of human antibodies that recognize native, cell-surface SMA. Antibodies will be evaluated for specificity and antitumor properties in "naked" form and when conjugated to novel alpha- and beta-emitting therapeutic radionuclides. Furthermore, we will examine antibody efficacy in the best available models of human prostate cancer to identify a lead candidate to advance into human clinical trials. PROPOSED COMMERCIAL APPLICATION: The overall goal of this poposal is to identify the most promising anti-PSMA antibody for treating prostate cancer and advance that therapeutic into clinical testing. The lead antibody construct identified with this proposed research will be moved into clinical trials and, if effective in humans, will be manufactured for commercial sale for the treatment of prostate cancer. The market for a successful immunotherapy includes men at risk for the development of recurrent or metastatic diseases. THis would include a significant fraction of individuals diagnosed with prostate cancer, or 179,000 individuals in the U.S. The ex-U.S. market is approximately equal in magnitutde.

Allogeneic TGF-Beta-Antisensed Cell Vaccine for Lung Cancer
Habib Fakhrai, Principal Investigator Novarx, San Diego, CA	R44 CA 96025-01
The purpose of this study is to conduct a Phase II clinical trial in patients with incurable non-small cell lung cancer (NSCLC). Our aim is to induce antitumor immune responses by immunizing patients with an experimental vaccine comprised of four allogeneic NSCLC cell lines genetically modified with a TGFbeta 2 antisense vector. By blocking secretion of the immunosuppressive molecule TGF-beta in this manner we inhibit one of the major mechanisms by which tumor cells evade immune surveillance. Developing an effective therapy for the disease that accounts for 30 percent of all cancer-related deaths will benefit the approximately 180,000 new patients that develop lung cancer in the United States each year. In a previous clinical trial, we have shown that injections with gene-modified allogeneic tumor cells induced cellular immune responses to autologous tumor cells. In this trial, 18 patients will be randomized into three cohorts that will receive 1.25 x 10exp7, 2.5 x 10exp7, or 5 x 10exp7 TGF-beta antisensemodified vaccine cells. Following completion of this phase of the trial, an additional 48 patients will be enrolled in the two cohorts that demonstrate the best clinical responses. We anticipate that our treatment will induce measurable clinical responses in some of the treated patients. PROPOSED COMMERCIAL APPLICATIONS: The potential patient pool for this study is 180,000 patients annually in the United States. When considering other parts of the world, the potential patient pool is significantly larger. Once the Phase II clinical trial is completed, and the efficacy of our method is proved, we will perform the subsequent phases of our clinical trial phases, as well as the commercialization of our method in partnership with a pharmaceutical company that has the facility to mass produce and market our vaccine.

Alphavirus prime-boost Vaccines for Prostate Cancer
Jason Gardner, Principal Investigator Progenics Pharmaceuticals, Inc., Tarrytown, NY	R43 CA 95928-01
Prostate cancer is the second leading cause of cancer death in American males, and there is an urgent need for novel therapeutics. Although androgen ablation temporarily controls metastatic disease, almost all tumors eventually become hormone-refractory and then rapidly progress since there is no other effective treatment. Prostate-specific membrane antigen (PSMA) is a splice variant that lacks the transmembrane domain and is thereby retained in the cytoplasm in normal prostate epithelial cells. In contrast, on prostate cancer cells, PSMA exists as a membrane glycoprotein with a large extracellular domain. This pattern of expression makes PSMA a compelling target for active immunotherapy. Our overall goal is to develop and clinically evaluate PSMA-based vaccines. We are pursuing both traditional purified protein vaccines and novel viral vector vaccines for eventual use alone and in heterologous prime-boost combinations in man. Alphavirus replicons and adjuvanted protein vaccines are ideal complements with the potential to mediate a wide array of potent, protective cellular and humoral immune responses in vivo. In this Phase I project, we will perform critical preclinical development activities to produce and characterize new alphavirus replicons, based on Semliki Forest virus, that express distinct forms of PSMA. A human HLA-A2 transgenic animal model will be employed to measure the quality and the magnitude of immune responses elicited in vivo by prime-boost combinations of PSMA vaccines, and these data will drive the selection of novel immunotherapies for clinical trials.

Cytotoxic FnRH Derivatives
L. Michael Glode, Principal Investigator Gonex, Denver, CO	R41 CA 96049-01
Hormonally responsive cancers, such as prostate and breast, are a major cause of morbidity and mortality in the aging population in the United States. These cancers can be treated by sex steroid antagonists by these compounds are costly and mutational escape occurs. Recent innovative approaches have used hormonotoxins to specifically target the cancer cells. Several such approaches are already in human clinical testing. We previously demonstrated that GnRH-toxin conjugates selectively kill pituitary gonadotrophs. Optimizing cell death by this method could result in a novel, single treatment modality for hormonally responsive cancers. In the current proposal, we will look at the toxicity of GnRH- PAP conjugate to fusion protein in a variety of cancer cell lines, and will correlate binding of GnRH-toxins to GnRHR mRNA expression in microdissected tumor and adjacent normal tissue. We hypothesize that cancer cells bearing the receptor will be killed upon exposure to GnRH toxins, and that the conjugate will be more cytotoxic than the fusion protein. This approach will extend the spectrum of utility of GnRH- toxins to hormone-resistant prostate and breast cancer and to cancers not thought of as hormone-responsive which nevertheless express the GnRH receptor, such as ovarian, and possibly pancreatic and hepatocellular carcinoma. PROPOSED COMMERCIAL APPLICATIONS: Use of GnRH-toxin may provide a single-shot approach to treat hormonally responsive as well as some hormone-resistant cancers. This would result in a superior, non-surgical and cost-effective means of treating these cancers.

Isolation of Novel Tumor Antigens
Hans Herweijer, Principal Investigator Mirus Corp., Madison, WI	R43 CA 95929-01
In vivo delivery of plasmid DNA expression vectors has shown to be an efficient means of inducing an immune response against the expressed gene sequence. Stimulating host immune responses against tumors using this method is an attractive cancer therapy approach. The effectiveness of genetic immunotherapy will depend on the properties of the tumor-associated antigen (TAA) used to induce the anti-tumor immune response, as well as the site and level of TAA expression. Mirus' intravascular non-viral gene delivery techniques have shown especially efficient at inducing transgene-directed immune responses, due to the types of cells that are transfected (including antigen presenting cells) and the high levels of expression that are obtained. The main Aim of this grant proposal is to use these proven highly efficient gene transfer techniques to evaluate TAAs in relevant in vivo tumor models, and to select novel TAAs from human tumor expression libraries. In Phase I, we will determine if these in vivo non-viral gene transfer techniques result in prophylactic and therapeutic anti-tumor immune responses in the B16 murine melanoma model. In parallel, we will determine the optimal genetic vaccination conditions (e.g., co-delivery of cytokine genes, minimal amount of pDNA required). In Phase II, subtracted expression libraries will be constructed from human tumor cells. TAA genes in the library that illicit anti-tumor responses will be selected by transferring individual clones or (partial) libraries into mice, followed by tumor challenge. Through successive rounds, specific and highly active TAAs will be isolated. Successful selection and evaluation of novel TAAs can be performed because of the very efficient immune response obtained following Mirus' intravascular gene delivery techniques, which can also be used to deliver TAAs to cancer patients.

A Hypoxia Activated HIF-1 & Inhibitor for Cancer Therapy
Lynn Kirkpatrick, Principal Investigator ProlX Pharmaceuticals, Pittsburgh, PA	R44 CA 78003-02
ProlX Pharmaceuticals, a company focusing on redox targets for development of anti-cancer therapies, has identified PX-478 as a novel hypoxia inducible factor (HIF) inhibitor and hypoxic bystander anti-cancer agent. The initial Phase I SBIR proposal, with aims to synthesize and evaluate novel agents that would be activated within a hypoxic tumor environment, provided strong evidence that PX-478 is selectively activated by hypoxic cancer cells and is an inhibitor of increased HIF-1 alpha and vascular endothelial growth factor (VEGF) production by the cells. The objective of this Phase II SBIR proposal is to move PX-478 through more extensive pre-clinical development. The specific aims of the proposal are: 1) to synthesize three salt preparations of PX-478 and to evaluate the physical chemical properties and properties and pharmacokinetics of each preparation to select a candidate for formulation and bioavailability studies; 2) to expand animal model evaluation of PX-478 and develop a biological endpoint assay based upon inhibition of HIF/VEGF expression; 3) to perform GLP toxicological evaluation of PX-478 in rodent and dog species. The conclusion of this Phase II SBIR will see ProIX Pharmaceuticals move PX-478 through complete pre-clinical development to IND submission to the FDA. PROPOSED COMMERCIAL APPLICATION: One in every five deaths in the US is doe to cancer. The overall cancer drug market exceeds $2 billion in the USA. There is a significant need to identify novel and selective small molecule-based cancer therapies. This proposal seeks to undertake full preclinical development of a novel anti HIF/hypoxic bystander, PX-478, and initiate a Phase I clinical trial for its eventual use as a therapy against cancer.

Development of Tumor-Targeted Drug Conjugates
Christopher Leaman, Principal Investigator Endocyte, Inc., West Lafayette, IN	R43 CA 96020-01
The objective of this proposal is to advance the development of a novel tumor- targeted antineoplastic drug conjugate. Our concept is based on the use of the vitamin folate to deliver a potent, covalently-attached chemotherapeutic drug to folate receptor (FR)-positive tumors in vivo and to potentiate a greater anti-tumor response in syngeneic animal models relative to that obtained with the un-conjugated drug. It is well-known that many types of human cancers vastly over-express FR and that folate-macromolecule conjugates specifically bind to and enter FR-expressing tumor cells via an endocytosis mechanism. Importantly, internalized folate-drug conjugates are exposed to both acidic and reducing environments within these intracellular endocytic compartments. Thus, high therapeutic efficacy may result from the use of potent folate-drug conjugates constructed with endosome-labile linkers. As such, the following specific aims are proposed: i) synthesize a novel acid-cleavable folate-drug conjugate, ii) synthesize a related thiol-labile folate- drug conjugate, iii) conduct in vitro dose-response cytotoxicity studies, and iv) conduct an initial therapeutic animal study with the more potent folate-drug conjugate. Following the completion of these specific aims, a Phase II project will be initiated which will include the submission of a corporate IND application for a folate-drug conjugate to the FDA and the initiation of an IND Phase I clinical study.

Poly (ADP-ribose) Polymerase & Doxorubicin Cardiotoxicity
Jon Mabley, Principal Investigator Inotek Corp., Beverly, MA	R43 CA 95807-01
There is solid and increasing experimental evidence for the role of oxidative stress, DNA injury and the activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP) in the pathogenesis of cardiac myocyte injury induced by various cytotoxic drugs. We hypothesize that the PARP pathway is involved in the cardiotoxic action of the cytotoxic anti-cancer drug doxorubican. Since cardiotoxicity is the main limiting factor, which restricts the use of this powerful approaches to counteract this toxicity are of great practical importance. In this proposal, we present evidence that (1) the developmental of doxorubican-induced myocardial depression is associated with the expression of iNOS and the production of peroxynitrite in the myocardium; (2) that PARP activation participate in free-radical in free-radical mediated myocardial injury; (3) that certain forms of drug-induced myocardial depression are associated with PARP activation in the myocardium and (4) that PARP deficient mice are resistant against doxorubican-induced myocardial depression. Using a combination approach of PARP deficient mice and potent pharmacological PARP inhibitors, here we proposed to (1) investigated the role of PARP in doxorubican-induced cardiotoxicity in rodent hearts in vivo; (2) to explore the molecular mechanisms of doxorubican- induced cardiotoxicity in cardiac myocytes in vitro, with focus on the involvement of PARP and (3) to investigated whether PARP inhibition influences the cytotoxicity of doxorubican in various human cancer cells in vitro. The current project will extend our understanding on the mechanism of doxorubican-induced cardiotoxicity, and will facilitate the preclinical development of potent PARP inhibitors to ameliorate this severe side effects of doxorubican. PROPOSED COMMERCIAL APPLICATIONS: The annual anticipated revenues for an effective therapeutic to prevent anti-cancer-drug induced cardiodepression is over $100 million in the US alone.

A-Z Cinntm Tarps: A single Treatment Cure for Cancer
Eleanor McGowan, Principal Investigator Aurazyme Pharmaceuticals, Inc., Marietta, GA	R43 CA 95937-01
Cancer is the second leading cause of death in the United States. In 2001, nearly 1.3 million Americans were diagnosed with cancer. The goal of this proposal is to establish the pre-clinical relevancy of a proprietary reversible linker, A-Z-CINN/TM, in creating a novel class of targeted pro-drugs (TARPs) as a single treatment cure for cancer. A-Z-CINN TARPs are modular constructs, which combine the targeting capabilities of monoclonal antibodies with the killing effectiveness of chemotherapy drugs. If the research is successful, A-Z-CINN TARPs will become a revolutionary anti-cancer therapy: conjugates that yield targeted destruction of tumor cells in a single treatment. This will lead to creation of a library of A-Z-CINN TARPs for treatment of primary and metastatic tumors. Specific aims of our research are: 1) Establish A-Z-CINN Linker as a viable platform technology for targeted anti-cancer drug delivery in vitro; 2) Create an initial library of five A-Z-CINN TARP conjugates in preparation for pre-clinical animal studies, and 3) Establish pre-clinical efficacy of TARPs in destroying tumors in a single treatment. Following successful completion of this research, AuraZyme will initiate pre- clinical safety and toxicology studies in support of an investigational New Drug Application with the FDA. PROPOSED COMMERCIAL APPLICATIONS: A-Z-CINN TARPS will become a platform technology for anti-cancer treatments. We will enter joint development and marketed partnerships with biotech and pharmaceutical companies. For Biotech companies A- Z-CINN will enhance the therapeutic benefit of their chemotherapy drugs.

Anti-angiogeneic and Anti-Tumor Drug for Human Glioma
Peter Mento, Principal Investigator Angio Biomedica Corp., Great Neck, NY	R43 CA 96077-01
Numerous novel approaches to cancer therapy are currently being examined including gene therapy, immunotherapy and combinations of traditional and novel therapies. By targeting multiple events in the proliferation and spread of cancer cells the effectiveness of treatments may be improved and resistance to therapy avoided. Since SF/HGF may promote tumor growth through multiple actions both on cancer cells as well as endothelial cells in the vasculature supplying the tumors., it provides an excellent therapeutic target. Many glioma cell lines contain c-met, the receptor for SF/HGF and are therefore promising targets for SH/HGF antagonism. In addition SF/HGF antagonists would also prevent proliferation of endothelial cells which are more easily accessible than tumor cells, may be targeted specifically without significant side effects, are not likely to develop drug resistance because of their genetic stability and can be targeted for different tumor types. The current grant proposes to use the novel approach of inhibition of the angiogenic and growth activities of scatter factor/hepatocyte growth factor (SF/HGF) using small molecules designed by phase display and computer modeling in order to inhibit cancer growth and enhance the effectiveness of chemotherapy. In these studies we will continue development of a compound we have already identified with SF/HGF antagonistic activity and pursue a directed screening process to identify additional SF/HGF antagonists with the goal of improved efficacy and minimal toxicity. PROPOSED COMMERCIAL APPLICATIONS: The Phase I and Phase II projects are designed to provide the key pre- clinical data to support regulatory filing and launch of clinical trials of SF/HGF and mimetic molecules for therapeutic angiogenesis. The company expects to pursue clinical development and commercialization with a pharmaceutical industry partner.

Development of DNA Methyltransferase Inhibitors as Anticancer Agents
Judy Mikovits, Principal Investigator Epigenx Pharmaceuticals, Inc., Santa Barbara, CA	R43 CA 92828-01A1
We propose to develop a new class of anticancer therapeutics based on inhibiting DNA cytosine methyltransferase (DNMT). Such compounds will form the basis for subsequent drug development, with potential applications to cancer therapy. DNA methylation plays an essential role in regulating gene expression; inhibiting the enzyme is a validated anticancer strategy. Sporadic forms of cancer have an epigenetic component, which are amenable to reversible intervention; thus are inherently less cytotoxic. We have developed an enzyme-based high throughput screen and identified small molecule DNMT inhibitors in an initial 8,000 compound screen. We have purchased a 50,000 compound library, and from this historical library will be submitted to a secondary cell-based screen to detect inhibition of methylation of a promoter containing a green fluorescence protein (GFP) reporter. Lead compounds will be tested in cell-based assays to determine their ability to alter the methylation pattern and expression of specific genes, in which hypermethylation has been suggested to play a role in tumorigenesis. The best candidates will be submitted to a panel of cytotoxicity studies and used as a design platform for the synthesis of new compounds. We expect to develop small molecule inhibitors with acceptable efficacy and toxicity profiles for testing in animal models of human cancers. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE

Creating clinically relevant Epidermal Growth Factor receptor antagonists
David Monticello, Principal Investigator Enchira Biotechnology Corp., The Woodlands, TX	R43 CA 95930-01
Proposed is the first application of an innovative and powerful protein engineering technique to create clinically relevant epidermal growth factor (EGF) antagonist variants that will inhibit signaling from the epidermal growth factor receptor (EGFr). The developed combinatorial biosynthesis technique is the first DNA shuffling method applicable to such small, diverse genes, and has generated demonstrably better DNA shuffled EGF libraries than has been done for any other DNA shuffling technique for any gene, regardless of size. We propose to screen this diverse combinatorial library to generate high affinity proteins that inhibit signaling from the ErbBl receptor Enabling an approach to create antagonistic growth factors will complement receptor blocking strategies involving antibodies or small molecules. Our collaboration partner at the University of Texas M.D. Anderson Cancer Center, Dr. Mien-Chie Hung, has the expertise to thoroughly evaluate each of our candidates in xenograft tumor animal studies. Successful outcome on this project will provide the impetus to pursue a host of broadly applicable small protein ligands against similar receptor-dependant malignancies. PROPOSED COMMERCIAL APPLICATION: We aim to engineer EGF variants for use as cancer therapeutics. Upon Phase I success, Phae II would result in an Investigative New Drug. Benefits to the treatment of cancer and thus the commercial applications of this therapy are clear. However, we are also attempting to use novel protein engineering tools to more generally enable a relatively neglected class of human therapeutics. The potential for improvements in human health and the range of commercial applications would be enormous.

Design & Discovery of Novel Antimetastatic MMP Inhibitors
Raj K. Singh, Principal Investigator Diversified Scientific, Inc., Birmingham, AL	R43 CA 86167-01A2
Metastatic spread of cancer via proteolytic degradation of host biomatrix continues to be the greatest barrier to cancer cure. Two key matrix-degrading metalloproteinases (MMPs), MMP-2 and -9, are implicated in these tumor progression events in humans. They are, therefore, targets for potential anticancer drug design because of their unique substrate specificity and tumor-related activities. The overall goal of this project is to design, synthesize and develop novel nonpeptidyl inhibitors selective for human MMP-2 and -9 as potential antimetastatic agents. A concerted approach based on novel chemical templates, enzyme-inhibitor analysis and a new human bioscreening model will be employed. The synthesis of new conformationally-restrained MMP inhibitors will involve specific substitutions at the P1-P1subsites of sulfonamide molecules. Based on pilot studies, we postulate that our active site-directed molecular modifications will render high potency and selectivity to inhibitors in target MMPs. Our team effort will have two specific goals: 1. Develop novel MMP-selective nonpeptidyl inhibitors using conformational-restriction chemistry and structure-assisted modeling strategies, and 2. Evaluate functional efficacy of lead MMP inhibitors using our defined human bioassays of tumor angiogenesis, invasion and metastasis, and initiate pharmacological studies. Phase I tasks will identify new inhibitor templates necessary for the synthesis of second-generation potent MMP-specific compounds. Parallel structure-function studies of MMP-2 and -9 with model inhibitors will provide new insights to improve pharmacokinetics and bioefficacy. Human tumor bioassays will elucidate the consequences of selective MMP inhibition on early (angiogenesis) and later (invasion) stages of metastasis. 3-D structural studies of MMP catalytic domains will also be exploited to further assist our drug design strategy. This bioevaluation will be clinically relevant for subsequent in vivo testing of potential anticancer agents. Thus, the scientific basis for future clinical trials and rationale for commercialization of new therapeutic drugs should be established for patients with cancers susceptible to MMP-2 and -9 inhibition. PROPOSED COMMERCIAL APPLICATION: Successful development of potent MMP-selective inhibitors as anticancer agents will impact both basic & clinical research and be translated into the therapeutic arena. A bioactive antiangiogenic/antimetastic agent would have a potentially large world-wide market. Synthetic inhibitors of key MMPs will also benefit other related biomedical fields including arthritis, fibrosis and vascular biology.

Novel Azabicyclooctance Inhibitors of P-glycoprotein
Zuping Xia, Principal Investigator Apogee Biotechnology Corp., Hersey, PA	R43 CA 96073-01
Cancer chemotherapy often provides temporary clinical improvement. However, tumor cells that survive the initial treatment often develop into cancers with multiple drug resistance (MDR). This is most often mediated by increased levels of the transport protein P-glycoprotein (PgP). A related family of transporters called MRPs are expressed by most normal tissues, and have complicated the development of therapies against MDR. Inhibitors of Pgp that do not concurrently inhibit MRPs are likely to be more effective clinical agents that previously tested non- selective MDR modulators. The overall goal of this project is to identify and characterize new compounds which are able to selectively overcome MDR. We have identified a new class of selective inhibitors of Pgp. Compound PGP-3005 is a substituted azabicyclo[2.2.2]octane that demonstrates excellent antagonism of Pgp in vitro, without affecting MRP1 activity. Further development of this class of MDR modulator supported by this SBIR Phase I grant will include: the design, synthesis and evaluation of additional azabicyclooctanes; and in vivo testing of either PGP-3005 or a superior analog for acute and delayed toxicity, pharmacokinetics and biodistribution and anti-MDR activity. These studies should allow a critical evaluation of the potential utility of this novel compound as a clinical agent. PROPOSED COMMERCIAL APPLICATIONS: P-glycoprotein mediated drug resistance is a very frequent limitation to successful chemotherapy of cancer. Compounds that effectively block this mechanism of resistance without altering the activities of related transport proteins could provide important therapeutic agents for a very large number of cancer patients. These compounds also have potential utility for improving drug delivery to the brain and enhancing the oral absorption of drugs.