Research
Project 1: GLIPR1–ΔTM Protein Therapy for Prostate Cancer
Project 2: Ligand-Directed Targeting in Prostate Cancer Metastasis
Project 3: Src as a Therapeutic Target in Prostate Cancer Bone Metastases
Project 4: Targeting FGF Signaling in Prostate Cancer Progression
Project 5: Separating the Chaff from the Wheat: Identifying Patients at Minimal Risk for Prostate Cancer Progression
Core A: Administrative Core
Core B: Biostatistics and Bioinformatics Core
Core C: Specimen Core
Project 1: GLIPR1–ΔTM Protein Therapy for Prostate Cancer
Timothy C. Thompson, Ph.D., Leader
Christopher J. Logothetis, M.D., Co-Leader
Extensive studies have defined GLIPR1 (glioma pathogenesis-related protein) as a secreted cytostatic/pro-apoptotic tumor suppressor protein that is down-regulated during prostate cancer progression through epigenetic mechanisms. Mechanistic studies have shown that GLIPR1 manifests tumor suppressor functions through coordinated cell type specific activities, including direct, tumor cell selective, pro-apoptotic activities mediated through reactive oxygen species (ROS)-c-jun-NH2 kinase (JNK) signaling. Recently we showed that GLIPR1 expression leads to down-regulation of specificity protein 1 (Sp1). Additional analysis showed that GLIPR1 expression suppressed c-myc through transcriptional repression that was dependent on Sp1-responsive GC/GT sites in the c-myc promoter and resulted in down-regulation of additional Sp1 target genes, including copper/zinc superoxide dismutase (CuZnSOD/SOD1) and manganese superoxide dismutase (MnSOD/SOD2). These data are in agreement with previous findings that Sp1 directly stimulates expression of multiple anti-oxidant proteins including CuZnSOD, MnSOD, and extracellular superoxide dismutase (ECSOD/SOD3). Western blotting analysis of c-myc targets showed that GLIPR1 overexpression resulted in significant suppression of key cell cycle regulatory proteins and also γ-glutamyl-cysteine synthetase, which catalyzes the first rate-limiting step in the synthesis of glutathione. Overall, GLIPR1 suppression of Sp1 activities represents a molecular switch that debilitates the anti-oxidant mechanisms/pathways that prevent cancer cells from ROS-mediated “self-destruction” and inhibits c-myc-mediated cancer cell proliferation. In preclinical studies we have found that recombinant GLIPR1 protein treatment results in tumor cell selective growth arrest and/or apoptotic cell death in multiple prostate cancer cell lines in vitro. Further preclinical studies using VCaP and/or PC-3 xenograft models demonstrated that recombinant GLIPR1 protein suppressed tumor growth and increased tumor cell apoptosis when administered intratumorally or intraperitoneally. In addition, effects on stromal cells were observed in treated tumors, including significant suppression of angiogenesis and macrophage infiltration.
Our first step in developing GLIPR1 protein therapy for prostate cancer is to test in situ delivery of a modified GLIPR1 protein (GLIPR1-ΔTM). This Phase Ib clinical trial will accomplish two important goals:
- Establish the safety of this therapeutic protein in a clinical setting (intraprostatic treatment prior to radical prostatectomy)
- Establish proof of principle for systemic use of GLIPR1-ΔTM
Specific Aims
Aim 1
Use orthotopic prostate cancer xenograft models to test the efficacy of GLIPR1-ΔTM treatment and to characterize the molecular and cellular changes that accompany suppression of primary tumor growth and lymph node (LN) metastasis induced by intratumoral (IT) or intraperitoneal (IP) delivery of GLIPR1-ΔTM protein.
- Test selected prostate cancer cell lines and established prostate cancer xenografts for suppression of primary tumor growth and LN metastasis following IT GLIPR1-ΔTM treatment.
- Test selected prostate cancer cell lines and established prostate cancer xenografts for suppression of primary tumor growth and LN metastasis following repeated IT and IP GLIPR1-ΔTM treatment.
- Analyze tumor cell cytotoxicity (apoptosis, necrosis, autophagy), alterations in tumor microenvironment, including angiogenic activities, immune cell infiltration, and bone marrow derived cell infiltration, and serum markers following IT or IP GLIPR1-ΔTM treatment (Aims 1.1 and 1.2) by using immunohistochemical and biochemical techniques. Changes in stromal cell activities will be correlated with suppression of tumor growth and LN metastasis.
- Analyze changes in stromal (mouse) and tumor cell (human) gene expression profiles and identify interactive stromal–epithelial genetic pathways following IT or IP GLIPR1-ΔTM treatment.
Aim 2
Determine selected pharmacokinetics and toxicological parameters of GLIPR1-ΔTM and submit IND for clinical trial.
- Determine specific pharmacokinetics parameters of GLIPR1-ΔTM following IT or IP administration.
- Conduct FDA-required preclinical studies and submit an IND.
Aim 3
Conduct a Phase Ib preoperative clinical trial for in situ GLIPR1-ΔTM in men who will undergo radical prostatectomy for prostate cancer.
- Assess the feasibility and safety of intraprostatic GLIPR1-ΔTM treatment.
- Assess the effect of GLIPR1-ΔTM in index cancer.
- Analyze the effect of GLIPR1-ΔTM on the tumor microenvironment.
Project 2: Ligand-Directed Targeting in Prostate Cancer Metastasis
Renata Pasqualini, Ph.D., Leader
Randall E. Millikan, M.D.,Ph.D., Co-Leader
Our laboratory has used in vivo phage display to (1) demonstrate how the vascular endothelium of organs is modified in a tissue-specific manner and (2) prove that the development of cancer is accompanied by specific abnormalities in the cells that form tumor-associated blood vessels. From previous work in an IRB-approved protocol involving phage-display screening with a random library injected intravenously into an irreversibly injured patient, a homing peptide was isolated from post-injection prostate biopsies. The selected sequence mimicked a motif of interleukin 11 (IL-11), and it in fact was bound to IL-11 receptor alpha (IL-11Rα.). Subsequent studies, including an extensive immunohistochemical analysis of primary and metastatic prostate cancer samples, showed increased expression of IL-11Rα. during disease progression, particularly in bone metastases. The seminal observation that the vasculature of human prostate cancer selectively binds a small peptide motif via IL-11Rα. raises many potential directions for both basic and translational research. In particular, it engenders the novel hypothesis that IL-11Rα.-mediated signaling is biologically important in the progression of prostate cancer (PCa) to a lethal phenotype and that understanding how this expression is regulated—particularly in relation to progression to a castrate-resistant state—will provide novel and relevant insights into the biology of human prostate cancer. The discovery of this prostate-homing peptide also suggests the use of novel imaging and therapeutic agents based on the selective binding. We have chosen to pursue aggressively a therapeutic application: We have produced an agent, BMTP-11 (Bone Metastasis Targeting Peptide 11), in which the selected peptide motif is combined with the mitochondrial-disrupting, and therefore apoptosis-inducing, moiety. The most important translational research issues in this context are.
- Does BMTP-11 selectively distribute to prostate cancer in human patients?
- How is IL-11R expression regulated? (This information is important for the selection of patients and the modulation of effective BMTP-11 treatment.)
- What are the toxicities of this agent, and how can they be mechanistically understood and thereby mitigated?
Specific Aims
Aim 1
Study the induction and activity of IL-11 and the IL-11Rα within the tumor microenvironment during prostate cancer progression.
Aim 2
Determine the stimuli mediating up-regulation and activation of the IL-11Rα. Potential interplay linking IL-11, IL-11Rα., and castrate-resistant tumor growth will be investigated.
Aim 3
Develop preclinical and clinical assays to evaluate BMTP-11 activity in patients.
Project 3: Src as a Therapeutic Target in Prostate Cancer Bone Metastases
Gary Gallick, Ph.D., Leader
John C. Araujo, M.D., Ph.D., Co-Leader
Current strategies for treatment of prostate cancer metastases in the bone that target mainly the primary tumor or preserve bone have only modestly affected survival. However, signaling pathways mediated by the Src family of tyrosine kinases affect not only tumor growth and invasion, but functions of osteoclasts and endothelial cells that contribute to metastatic growth. This project will test the central hypothesis that therapeutic strategies using Src inhibitors currently in clinical trial will prove efficacious in the treatment of prostate cancer metastases in the bone. The rationale for this hypothesis is that Src inhibitors affect tumor cell/microenvironment interactions that contribute to the “vicious cycle” of bone formation, degradation, and tumor growth. The studies are based, in part, and is based, in part, on the promise of an ongoing phase I/II clinical trial for metastatic prostate cancer using the combination of dasatinib (an SFK/Abl inhibitor) and docetaxel. This project will combine mechanistic-based strategies in preclinical mouse model systems with a phase III clinical trial using dasatinib plus docetaxel to examine the specific contributions of Src in the host and tumor cell contributing to metastatic to growth in the bone.
Specific Aims
Aim 1
Determine the role of SFK inhibition in tumor cells, host cells, and both in affecting growth of PCa cells following intratibial injection into nude mice.
Aim 2
Determine molecular alterations in the tumor and host correlating with the effectiveness of dasatinib.
Aim 3
Integrate this knowledge with a phase III trial using dasatinib in combination with docetaxel in select patients with castrate-resistant prostate cancer and bone metastases and correlate changes in molecular markers of Src and bone preservation with clinical course of the disease.
The trial will serve as a platform to associate markers of Src activation with baseline and serial change(s) in bone turnover markers. Thus, the experiments in Project 3 are novel in that they build on a promising therapeutic strategy, which we also view as reiterative, where our increased knowledge of Src’s effects in tumor/bone interaction will help dictate clinical trial design, and the clinical trials will help refine modeling the disease in preclinical studies.
Project 4: Targeting FGF Signaling in Prostate Cancer Progression
Nora M. Navone, M.D., Ph.D., Leader
Paul Corn, M.D., Ph.D., Co-Leader
Wallace McKeehan, Ph.D., Subcontract Leader
Prostate cancer is the second leading cause of cancer death in men in the United States. Localized prostate cancer can be cured by androgen ablation, but when the disease escapes the confines of the gland, the prospects for cure decrease drastically and the disease becomes “castrate resistant.” Bone is the primary site of castrate-resistant disease progression, which is associated with a poor prognosis. The fibroblast growth factor (FGF)/FGF receptor (FGFR) complex, a signaling axis involving multiple FGF ligands and receptors, mediates tumor–stromal interactions and is one of the most commonly altered signaling pathways during prostate cancer progression. Expression of FGFR1, multiple FGF ligands, and FGFR adaptor FRS2a has been observed in prostate cancer epithelial cells. Our recent studies have defined a mouse model of prostate cancer highly dependent on FGF signaling and have implicated FGF9 in the osteoblastic progression of human prostate cancer cells in bone. The results of our preliminary studies support a notion that during bone metastasis, the prostate cancer cells that aberrantly express both FGF and FGFRs create a new “compartment” in bone as source and recipient of additional FGF-mediated signaling, thus subverting homeostasis.
The implication of the FGF axis in prostate cancer progression suggests that FGFR blockade represents a new therapeutic opportunity for men with castrate-resistant prostate cancer. Recently, TKI258, a receptor tyrosine kinase inhibitor (TKI) with strong activity against FGFR1-3 (IC50 < 40 nM), has become available and is being used as an experimental new drug for solid tumors. The main goal of this proposed project is to establish the feasibility of using TKI258 to modulate FGF signaling in men with castrate-resistant prostate cancer and to correlate FGF signaling modulation with clinical disease progression. We will assess the effect of TKI258 on human prostate cancer xenografts growing in the prostate and bone of castrated immunodeficient male mice (Aim 1) and also on mouse models of prostate cancer (Aim 2) to identify markers of response to TKI258 therapy directly related to FGF signaling. We will then perform a proof-of-principle clinical study with TKI258 in men with castrate-resistant prostate cancer and bone marrow infiltration (Aim 3). The study will create an annotated tissue resource and will permit validation of FGF signaling responsive markers emerging from Aims 1 and 2. This will be the first clinical study to assess the effect of TKI258 in prostate cancer.
Project 5: Separating the Chaff from the Wheat: Identifying Patients at Minimal Risk for Prostate Cancer Progression
Christopher Amos, Ph.D., Leader
Jeri Kim, M.D., Co-Leader, Clinical
Ivan P. Gorlov, Ph.D., Co-Leader, Scientific
Data supporting conservative management of cases of clinically localized prostate cancer (PCa) can be gleaned from autopsy series, population-based studies, and meta-analyses. Despite limitations, these studies show that the course of low-grade PCa is protracted and that the risk of disease-specific death, even after 20 years of follow-up, is low. Considerable PCa tumor heterogeneity makes individualization of cancer therapy imperative. Data from both primary prevention trials (with finasteride or dutasteride) and the results from treating patients who have cancers with favorable prognoses demonstrate that 5-α reductase inhibition reduces the frequency of detected low-grade prostate cancers. Taken together, these clinical observations suggest the existence of a subset of PCas sensitive to dihydrotestosterone (DHT) depletion. Identifying DHT-dependent (5-α reductase inhibition–sensitive) cancers may spare patients the complications of radiation or surgery. We postulate that cancers that are not DHT-dependent (finasteride insensitive) are likely to be biologically different from finasteride-sensitive cancers. We further postulate that the finasteride-insensitive tumors are more aggressive than are those that are finasteride sensitive. Therefore, discrimination between finasteride-sensitive and -insensitive tumors may help to separate indolent from aggressive cases.
We helped develop a preoperative model to explore PCa’s complexities. We established the feasibility of conducting clinical investigations of low-volume and low-grade PCa in a cell type–specific manner and showed that short-term exposure of PCa to a preventive or therapeutic agent can be used to inform the long-term consequences of therapy. We used the published gene expression data to evaluate the biologic effect of a 4-month intervention with dutasteride in men with clinically localized PCa who were undergoing prostatectomy. Our initial analysis showed interindividual variation in the response to dutasteride treatment, and in some patients the expression profile was normalized, whereas in others it was not. Our goal is develop an approach to discriminate between indolent and aggressive PCas (i.e., 5-α reductase inhibition–sensitive versus 5-α reductase inhibition–insensitive) by observing a gene response to provocative short-term finasteride treatment of early stage disease. Successful completion of this project will enable testing of a short-term intervention with finasteride in men with early PCa, followed by marker profiles to determine the biologic potential of tumors, which then may yield two dynamic stratification strategies: (1) If marker profiles are predictive of therapeutic benefit, then men with finasteride-sensitive tumors may continue to be treated with the drug; (2) however, should these marker profiles prove to have prognostic value, then men with finasteride-sensitive tumors may undergo active surveillance.
Specific Aims
Aim 1
Identify a gene expression signature of short-term finasteride exposure. We will use archived fresh-frozen tissues from a randomized placebo-controlled presurgical trial of finasteride in men with clinically localized PCa. Patients were randomly assigned to one of two treatment groups: for 4–6 weeks before surgery, 100 patients received 5 mg finasteride daily, and 100 received placebo daily. Ex vivo core biopsies performed postprostatectomy were used as the source of tissue for laser capture microdissection and gene expression arrays, and samples from this trial are available. PCas in treated versus untreated patients will be used to identify a molecular signature of finasteride treatment that may be linked to the cancer-suppression potential of 5-α reductase inhibition. Samples will be stratified within Gleason grade to reduce heterogeneity in tumor markers associating with grade rather than treatment. In achieving this aim, we will identify genes sensitive to the treatment and those that are associated with PCa initiation and progression.
Aim 2
Validate the molecular signature identified in Aim 1 in men with low-risk PCa undergoing active surveillance, who are being treated with dutasteride. Results from Aim 1 should allow us to develop a panel of at most 20 markers that predict response to 5-α reductase inhibition. We will develop mRNA expression signatures or immunohistochemical markers that can be applied to biopsy specimens from men with clinically localized intermediate-grade PCa who are undergoing active surveillance to validate the markers’ predictive accuracy for benefit from 5- reductase inhibition (decreased cancer rate in the repeat biopsies, avoiding unnecessary treatment and local therapy’s potential toxicity, including impotence and urinary incontinence).
Aim 3
Characterize the biomarkers developed in Aims 1 and 2 to determine whether these primarily predict response to treatment or have a role as prognostic markers. We anticipate that some of these markers may be associated with disease progression or survival (prognostic markers). Studies will identify a subset of nascent DHT-dependent tumors (indolent tumors). We propose to study a cohort of active-surveillance participants at MD Anderson Cancer Center and other PCa SPORE sites.
Core A: Administrative Core
Christopher J. Logothetis, M.D., Director
Timothy C. Thompson, Ph.D., Co-Director
The principal role of the Administrative Core of the MD Anderson Cancer Center Prostate SPORE is to expand the integration of investigators from diverse scientific disciplines who have joined the translational research effort in prostate cancer. It is the purpose of the Administrative Core to provide continuous leadership and general administrative support for all SPORE-related activities. Dr. Christopher Logothetis, Director, and Dr. Timothy Thompson, Co-Director, provide support for all SPORE research projects, cores, and programs and ensure compliance with all governmental regulations, policies, and requirements. The Administrative Core coordinates data quality control and quality assurance in conjunction with the Biostatistics and Bioinformatics and Specimen Cores and the Internal and External Advisory Boards. The Administrative Core convenes all meetings of the SPORE, including seminars and lectures presented by scientific leaders in basic, translational, and clinical prostate cancer research brought to the SPORE by the directors. With the program directors, the Administrative Core monitors the selection of projects and trainees for the Developmental Research and Career Development Programs, respectively. Dr. Logothetis chairs the Executive Committee, composed of the co-principal investigator and senior scientific leaders with extensive SPORE experience. To address the ongoing needs of the minority and medically underserved communities in Houston and Harris County, Texas, Dr. Curtis Pettaway (collaborator) has developed the Prostate Outreach Program integrated into SPORE research through the Administrative Core. Special contributor Dr. Randall Millikan has developed the MD Anderson Prostate Research database (Research Repository), which serves the increasing data and bioinformatics needs of SPORE investigators, in collaboration with the Biostatistics and Bioinformatics and Specimen Cores. The Patient Advocacy Program brings patient representation to the SPORE and increases awareness and education of prostate cancer research, treatment, and prevention in the community.
Core B: Biostatistics and Bioinformatics Core
Kim-Anh Do, Ph.D., Director
Kevin Coombes, Ph.D., Co-Director
The research proposed by The University of Texas MD Anderson Cancer Center SPORE in Prostate Cancer encompasses a broad range of activities, including studies in cell lines, animal models, and clinical trials. These studies will generate many different types of data, including clinical, epidemiological, biochemical, immunohistochemical, pharmacokinetics, genotype, and immunologic. The Biostatistics and Bioinformatics Core provides comprehensive biostatistics and bioinformatics expertise to ensure the statistical integrity and to optimize data analysis of the studies by the SPORE. It will incorporate sound experimental design principles within each project that will enhance interpretability of study results, will carry out data analyses using appropriate statistical methodology, and will contribute to interpretation of results through written reports and frequent interaction with project investigators. Members of the Core will participate in monthly SPORE meetings with all project investigators, ensuring that proper consideration is taken of biostatistics and data management issues during all phases of SPORE experiments. The Biostatistics and Bioinformatics Core will further provide an integrated data management system to facilitate communication between all projects and cores, which will be customized to meet the needs of the Prostate Cancer SPORE. This process includes prospective data collection, data quality control, data security, and patient confidentiality. Thus, from inception to reporting, translational experiments will benefit from SPORE resources that will be used to augment existing MD Anderson Cancer Center biostatistics resources.
Specific Aims
Aim 1
To provide valid statistical designs of laboratory research, clinical trials, and translational experiments arising from the ongoing research of the SPORE.
Aim 2
To develop and conduct the innovative statistical modeling, simulations, and data analyses needed by the projects, developmental projects, and other cores to achieve their specific aims.
Aim 3
To ensure that the results of all projects are based on well-designed experiments and are appropriately interpreted and to assist in the preparation of manuscripts describing these results.
Aim 4
To develop integrated computational libraries and tools for producing documented, reproducible statistical analyses and to make these tools available to all SPORE participants.
Core C: Specimen Core
Patricia Troncoso, M.D., Director
Randall Millikan, M.D., Co-Director
The Specimen Core will provide SPORE investigators with well-characterized biologic specimens, including tissues, blood, and tissue derivatives that are essential for achieving the aims of the projects. The Specimen Core has a large repository of paraffin blocks, frozen samples, plasma, serum, and bone marrow that spans the entire spectrum of prostate cancer. The repository includes primary tumors and metastases from therapy-resistant tumors and tumors derived from radical prostatectomy specimens from patients given novel preoperative therapies as part of studies conducted at The University of Texas MD Anderson Cancer Center and other, multi-institutional efforts. This material, supplemented in select cases with matching biopsy specimens, plasma, serum, and bone marrow aspirates collected before therapy, will provide SPORE investigators with optimal tissue samples with which to address the proposed basic and translational research tissue requirements of the projects. We have also established biologic models (cell lines and xenografts) relevant to the projects. Tissue requests and approval by the Tissue Acquisition and Distribution Committee will be handled electronically. Tissue derivatives, including tissue microarrays, cRNA, and DNA, will optimize the use of limited samples and enhance collaboration among investigators at MD Anderson and other institutions. Structured information derived from standardized, high-throughput assays of differential gene expression, both of protein (immunohistochemistry) and RNA (oligonucleotide arrays and multiplexed PCR), will be available to individual SPORE investigators to facilitate modular and gene network analysis in specific clinical contexts. A unique feature of the Specimen Core will be the ability to link comprehensive clinical and pathologic information to the morphologic and molecular characterization of selected pathways. This linkage will be accomplished in cooperation with the Biostatistics and Bioinformatics Core by using a Web-based portal. By using this Web-based system to access and query SPORE data, we will pool laboratory resources, facilitate the translational research proposed in the projects, and accelerate successful achievement of the proposed aims.
Specific Aims
Aim 1
Collect, process, annotate, characterize, store, and distribute human biospecimens related to prostate cancer.
Aim 2
Create well-characterized and quality-controlled tissue derivatives for translational research (including xenografts, cell lines, tissue microarrays, protein lysates, RNA, and DNA) and conduct selected studies, including immunohistochemical, reverse-transcription polymerase chain reaction (RT-PCR), and reverse-phase protein array (RPPA) evaluations.
Aim 3
Provide investigators with expertise to optimally select and use biospecimen resources and analytical techniques for tissue-based studies.
Aim 4
Provide longitudinal clinical annotation for biospecimens, consisting of structured data on comorbidity, family history, diagnosis, treatment, and outcome.
Aim 5
Provide an integrated information system that supports a secure archive (for both clinical data and datasets from translational studies) along with a corresponding application for browsing and querying data related to biospecimen repositories, clinical annotation, and translational experiments.
