An omic and multidimensional spatial atlas from serial biopsies of an evolving metastatic breast cancer

Mechanisms of therapeutic resistance and vulnerability evolve in metastatic cancers as tumor cells and extrinsic microenvironmental influences change during treatment. To support the development of methods for identifying these mechanisms in individual people, here we present an omic and multidimensional spatial (OMS) atlas generated from four serial biopsies of an individual with metastatic breast cancer during 3.5 years of therapy. This resource links detailed, longitudinal clinical metadata that includes treatment times and doses, anatomic imaging, and blood-based response measurements to clinical and exploratory analyses, which includes comprehensive DNA, RNA, and protein profiles; images of multiplexed immunostaining; and 2- and 3-dimensional scanning electron micrographs. These data report aspects of heterogeneity and evolution of the cancer genome, signaling pathways, immune microenvironment, cellular composition and organization, and ultrastructure. We present illustrative examples of how integrative analyses of these data reveal potential mechanisms of response and resistance and suggest novel therapeutic vulnerabilities.

Multiomics analysis of serial PARP inhibitor treated metastatic TNBC inform on rational combination therapies

In a pilot study, we evaluated the feasibility of real-time deep analysis of serial tumor samples from triple negative breast cancer patients to identify mechanisms of resistance and treatment opportunities as they emerge under therapeutic stress engendered by poly-ADP-ribose polymerase (PARP) inhibitors (PARPi). In a BRCA-mutant basal breast cancer exceptional long-term survivor, a striking tumor destruction was accompanied by a marked infiltration of immune cells containing CD8 effector cells, consistent with pre-clinical evidence for association between STING mediated immune activation and benefit from PARPi and immunotherapy. Tumor cells in the exceptional responder underwent extensive protein network rewiring in response to PARP inhibition. In contrast, there were minimal changes in the ecosystem of a luminal androgen receptor rapid progressor, likely due to indifference to the effects of PARP inhibition. Together, identification of PARPi-induced emergent changes could be used to select patient specific combination therapies, based on tumor and immune state changes.

Assessment of Global Trends in the Diagnosis of Mesothelioma From 1990 to 2017

IMPORTANCE

It is difficult for policy makers and clinicians to formulate targeted management strategies for mesothelioma because data on current epidemiological patterns worldwide are lacking.

OBJECTIVE

To evaluate the mesothelioma burden across the world and describe its epidemiological distribution over time and by sociodemographic index (SDI) level, geographic location, sex, and age.

DESIGN, SETTING, AND PARTICIPANTS

Annual case data and age-standardized rates of incidence, death, and disability-adjusted life-years associated with mesothelioma among different age groups were obtained from the Global Burden of Disease 2017 database. The estimated annual percentage changes in age-standardized rates were calculated to evaluate temporal trends in incidence and mortality. The study population comprised individuals from 21 regions in 195 countries and territories who were diagnosed with mesothelioma between 1990 and 2017. Data were collected from May 23, 2019, to January 18, 2020.

MAIN OUTCOMES AND MEASURES

Primary outcomes were incident cases, deaths, and their age-standardized rates and estimated annual percentage changes. Secondary outcomes were disability-adjusted life-years and relative temporal trends.

RESULTS

Overall, 34 615 new cases (95% uncertainty interval [UI], 33 530-35 697 cases) of mesothelioma and 29 909 deaths (95% UI, 29 134-30 613 deaths) associated with mesothelioma were identified in 2017, and more than 70% of these cases and deaths were among male individuals. In 1990, the number of incident cases was 21 224 (95% UI, 17 503-25 450), and the number of deaths associated with mesothelioma was 17 406 (95% UI, 14 495-20 660). These numbers increased worldwide from 1990 to 2017, with more than 50% of cases recorded in regions with high SDI levels, whereas the age-standardized incidence rate (from 0.52 [95% UI, 0.43-0.62] in 1990 to 0.44 [95% UI, 0.42-0.45] in 2017) and the age-standardized death rate (from 0.44 [95% UI, 0.37-0.52] in 1990 to 0.38 [95% UI, 0.37-0.39] in 2017) decreased, with estimated annual percentage changes of -0.61 (95% CI, -0.67 to -0.54) for age-standardized incidence rate and -0.44 (95% CI, -0.52 to -0.37) for age-standardized death rate. The proportion of incident cases among those 70 years or older continued to increase (from 36.49% in 1990 to 44.67% in 2017), but the proportion of patients younger than 50 years decreased (from 16.74% in 1990 to 13.75% in 2017) over time. In addition, mesothelioma incident cases and age-standardized incidence rates began to decrease after 20 years of a complete ban on asbestos use. For example, in Italy, a complete ban on asbestos went into effect in 1992; incident cases increased from 1409 individuals (95% UI, 1013-1733 individuals) in 1990, peaked in 2015 after 23 years of the asbestos ban, then decreased from 1820 individuals (95% UI, 1699-1981 individuals) in 2015 to 1746 individuals (95% UI, 1555-1955 individuals) in 2017.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that incident cases of mesothelioma and deaths associated with mesothelioma continuously increased worldwide, especially in resource-limited regions with low SDI levels. Based on these findings, global governments and medical institutions may consider formulating optimal policies and strategies for the targeted prevention and management of mesothelioma.

Abstract 46: A new class of precision therapeutics that inhibit prostate cancer mediated bone destruction

The destructive nature of bone metastases dominates the clinical management of advanced prostate cancer (PCa) and is a common cause of morbidity and mortality. Our current ability to therapeutically target this process is limited. Here we describe the synthesis and functional characterization of the first-in-class Dual Acting Bone Defending agents (DABDs), which couple a small molecule therapeutic that inhibits cell movement to bone trophic bisphosphonates. Upfront in-vitro screens assessed DABD efficacy at inhibiting PCa cell migration and invasion and osteoclast mediated bone destruction. Systemic models of PCa metastasis, inclusive of intracardiac (IC) and intratibial (IT) injection models, were deployed to characterize tolerance and efficacy in-vivo. Finally, in-vitro characterization of DABD molecular mechanism of action was performed, as guided by the existing knowledge base related to the parental compounds. Results demonstrated that DABDs inhibit PCa cell migration and invasion, chemically bind hydroxyappetite, and inhibit osteoclast mediated bone destruction in vitro. Following IC injection of PCa cells, a model where cells are placed into circulation, metastasize to bone, grow and induce bone destruction, emulating the clinical scenario in humans, DABD treatment inhibited circulating PCa cells from forming new bone metastasis and prolonged life in a dose-dependent fashion. In the IT mouse models of established metastatic lesions, DABDs induce reversion of PCa cell growth and disrupt further bone destruction. DABDs at doses 1000 fold higher than those associated with efficacy are well tolerated. At the molecular level, DABDs retain the molecular mechanisms of action of their constituent chemicals. They inhibit farnesyl diphosphate synthase (FDPS), in the mevalonate pathway, leading to decreased prenylation of small GTPases, including the Ras related protein, Rap-1A, as well as inhibit Raf1 activation, inducing apoptosis and impaired cell movement, respectively. DABDs are a new class of agents that inhibit formation of new bone metastasis, revert growth of established metastasis, prolong life, and have a high potential for improving clinical outcome in humans.

Citation Format: Ryan R. Gordon, Abhinandan Pattanayak, Wenqi Li, Raymond Bergan. A new class of precision therapeutics that inhibit prostate cancer mediated bone destruction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 46.

Abstract 357: Cancer associated macrophage like cells predict aggressive disease in local and metastatic prostate cancers

Background:

Prostate cancers (PC) are intrinsically complex, with few prognostic biomarkers that differentiate aggressive and indolent disease. Cancer associated macrophage like cells (CAMLs) have shown to be significant independent prognostic indicators for poor survival in tumors if engorged to ≥50μm. However, no group has examined CAMLs' in PC. In this prospective pilot study, we analyzed PSA & ≥50μm CAML presence in (n=51) Stage I-III & (n=41) metastatic PC (mPC) prior to the start of new treatments to examine CAMLs' on outcomes. We found that ≥50μm CAML presence significantly predicted worse patient survival in mPC. These preliminary results suggest that CAMLs may serve as a cheap, non-invasive prognostic biomarker that predicts for worse outcomes in both local & mPC prior to new therapies.

Methods:

We prospectively recruited (n=92) PC patients in this pilot study to examine CAML's prognostic significance in non-metastatic (stages I-III) and mPC. Of (n=92) total patients, 15% (n=14/92) were stage I, 32% (n=29/92) stage II, 9% (n=8/92) stage III, and 45% (n=41/92) Stage IV. Prior to the induction of new therapy or first line therapy for newly diagnosed patients, 7.5mL peripheral baseline (BL) blood was collected. Blood was filtered via CellSieveTM microfiltration, which excludes cells by size ≥7μm. In parallel, changes in PSA was monitored to compare prognostic significance against ≥50μm CAMLs. Wilcoxon univariate analysis was used to analyze ≥50μm CAMLs and PSA in progression free survival (PFS) and overall survival (OS).

Results:

CAML's were identified in 78.9% (n=71/90) of available BL samples, with two samples failing from clotting. Stage I-III patients had an average of ~3 CAMLs/7.5mL blood, whereas mPCs contained ~6 CAMLs/7.5mL. Average CAML size increased linearly with advancing stage of disease with stage I patients averaging 23μm, stage II 33μm, stage III 65μm, and stage IV 78μm. Of available BL samples, 41% (n=38/90) patients with ≥50μm CAMLs significantly predicted for worse PFS (HR=10.0, p<0.001, 95%CI=0.07-0.31) and OS (HR=34.2, p<0.001, 95%CI=0.03-0.21). Further, ≥50μm CAMLs significantly predicted for poorer survival in mPC with PFS (HR=9.4, p=0.028, 95%CI=0.18-0.84) and OS (HR=5.1, p=0.003, 95%CI=0.07-0.53), but only non-significantly trended in non-metastatic disease. Initial analysis of PSA found that high PSA at BL was a significant predictor for worse outcomes in patients, while changes in PSA was not a predictor.

Conclusions:

CAMLs have shown potential as a predictive non-invasive blood based biomarker across multiple solid malignancies, and here we compared this biomarker in PC. While preliminary, these data suggests that engorged CAML presence prior to the start of new treatment may be a statistically significant predictor of survival in both the local and metastatic setting, and a larger validation cohort should be established.

Citation Format: Daniel J. Gironda, Raymond Bergan, R K. Alpaugh, Daniel C. Danila, Tuan L. Chuang, Brenda Y. Hurtado, Thai Ho, Cha-Mei Tang, Daniel L. Adams. Cancer associated macrophage like cells predict aggressive disease in local and metastatic prostate cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 357.

Bone-on-a-chip: microfluidic technologies and microphysiologic models of bone tissue

Bone is an active organ that continuously undergoes an orchestrated process of remodeling throughout life. Bone tissue is uniquely capable of adapting to loading, hormonal, and other changes happening in the body, as well as repairing bone that becomes damaged to maintain tissue integrity. On the other hand, diseases such as osteoporosis and metastatic cancers disrupt normal bone homeostasis leading to compromised function. Historically, our ability to investigate processes related to either physiologic or diseased bone tissue has been limited by traditional models that fail to emulate the complexity of native bone. Organ-on-a-chip models are based on technological advances in tissue engineering and microfluidics, enabling the reproduction of key features specific to tissue microenvironments within a microfabricated device. Compared to conventional in-vitro and in-vivo bone models, microfluidic models, and especially organs-on-a-chip platforms, provide more biomimetic tissue culture conditions, with increased predictive power for clinical assays. In this review, we will report microfluidic and organ-on-a-chip technologies designed for understanding the biology of bone as well as bone-related diseases and treatments. Finally, we discuss the limitations of the current models and point toward future directions for microfluidics and organ-on-a-chip technologies in bone research.

Snapshot: Trial Types in Precision Medicine

Integrating precision diagnostics into personalized treatments requires understanding how biomarkers relate to clinical outcomes. Various clinical data collection methods exist, each with strengths and weaknesses. Interventional data are high quality but narrowly focused. Real-world data (RWD) provide broader information but with variable quality. Master protocols allow better efficiency in data collection. The master observational trial bridges the gap between interventional and retrospective RWD collection methods. To view this SnapShot, open or download the PDF.

A Randomized Parallel Controlled Phase II Trial of Recombinant Human Endostatin Added to Neoadjuvant Chemotherapy for Stage III Breast Cancer

BACKGROUND

To explore the potential advantage of preoperative anti-angiogenosis therapy, we implemented a study to evaluate the efficacy of recombinant human endostatin (EN) in combination with neoadjuvant chemotherapy in the treatment of stage III breast cancer.

PATIENTS AND METHODS

Eighty-seven patients were randomized to neoadjuvant TEC (docetaxel, epirubicin, and cyclophosphamide) or to EN+TEC, followed by surgery. The primary endpoint was the objective response rate (ORR). Secondary endpoints included pathologic complete response (pCR), relapse-free survival (RFS), overall survival (OS), and safety.

RESULTS

Patients receiving EN+TEC achieved significantly higher ORR (81.82%; 36/44) compared with those receiving TEC (58.14%; 25/43; P=0.016). There was a non-significant trend of increased pCR with EN treatment (15.91% vs. 6.98%). The median follow-up was 54 months and revealed a significantly higher RFS with EN+TEC (median, 67.3 months; 95% confidence interval [CI], 61.0-73.7 months), compared with TEC (median, 55.0 months; 95% CI, 48.3-61.7 months; P =0.014). EN+TEC also significantly improved OS (74.2 months; 95% CI, 68.9-79.6 months), compared with TEC (59.1 months; 95% CI, 52.0-66.1 months; P =0 .006). The 3- and 5-year OS rates are estimated to be 88.5% and 82.8% with EN+TEC and 76.7% and 54.4% with TEC, respectively. Cox proportional regression analyses showed that EN+TEC was associated with improved OS (hazard ratio, 0.377; 95% CI, 0.418-0.959; P =0 .041). There was no significant difference in adverse events between EN+TEC and TEC.

CONCLUSION

The combination of EN+TEC neoadjuvant chemotherapy significantly improved the ORR and OS, suggesting a benefit of adding anti-angiogenesis to standard chemotherapy in the treatment of locally advanced breast cancer.

A way forward for cancer prevention therapy: personalized risk assessment

Cancer is characterized by genetic and molecular aberrations whose number and complexity increase dramatically as cells progress along the spectrum of carcinogenesis. The pharmacologic application of agents in the context of a lower burden of dysregulated cellular processes constitutes an efficient strategy to enhance therapeutic efficacy, and underlies the rationale for using cancer prevention agents in high-risk populations. A longstanding barrier to implementing this strategy is that the risk in the general population is low for any given cancer, many people would have to be treated in order to benefit a few. Therefore, identifying and treating high-risk individuals will improve the risk: benefit ratio. Currently, risk is defined by considering a relatively low number of factors. A strategy that considers multiple factors has the ability to define a much-higher-risk cohort than the general population. This article will review the rationale for evaluating multiple risk factors so as to identify individuals at highest risk. It will use breast and lung cancer as examples, will describe currently available risk assessment tools, and will discuss ongoing efforts to expand the impact of this approach. The high potential of this strategy to provide a way forward for developing cancer prevention therapy will be highlighted.

Abstract LB-C11: Targeting metastatic prostate cancer with a multi-functional therapy approach

Prostate cancer (PCa) cells move throughout the body, hone to and destroy the bone microenvironment, grow and thereby cause death. Our historical inability to target cell movement has precluded our realization of multifunctional therapy wherein each of these processes is targeted. Our group has recently shown that inhibition of intracellular activation of Raf1 with the small molecule therapeutic, KBU2046, permits for the first time selective inhibition of cell motility. Here we demonstrate that simultaneous disruption of multiple distinct functions that drive progression of PCa to induce death results in advanced disease control. Using an orthotopic murine model of human PCa metastasis, KBU2046 combined with docetaxel achieves sustained anti-tumor action and improved inhibition of metastasis, compared to monotherapy. KBU2046 does not interfere with androgen deprivation or androgen receptor antagonist mediated hormone therapy in either in vitro or in vivo models. Cell movement is necessary for osteoclast-mediated bone degradation. KBU2046 inhibits Raf1 and its downstream activation of MEK1/2 and ERK1/2 in osteoclasts, inhibiting cytoskeleton rearrangement, resorptive cavity formation and bone destruction in vitro, with improved effects observed when the bone microenvironment is chemically modified by pretreatment with zoledronic acid. Using a murine cardiac injection model of human PCa bone destruction quantified by computed tomography, KBU2046 plus zoledronic acid exhibited improved inhibitory efficacy, compared to monotherapy. The combined disruption of pathways that drive cell movement, honing to the bone and growth constitutes a multi-functional targeting strategy that provides advanced disease control.

Citation Format: Ryan Gordon, Limin Zhang, Abhinandan Pattanayak, Wenqi Li, Raymond Bergan. Targeting metastatic prostate cancer with a multi-functional therapy approach [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr LB-C11. doi:10.1158/1535-7163.TARG-19-LB-C11

Modeling MEK4 Kinase Inhibitors through Perturbed Electrostatic Potential Charges

MEK4, mitogen-activated protein kinase kinase 4, is overexpressed and induces metastasis in advanced prostate cancer lesions. However, the value of MEK4 as an oncology target has not been pharmacologically validated because selective chemical probes targeting MEK4 have not been developed. With advances in both computer and biological high-throughput screening, selective chemical entities can be discovered. Structure-based quantitative structure-activity relationship (QSAR) modeling often fails to generate accurate models due to poor alignment of training sets containing highly diverse compounds. Here we describe a highly predictive, nonalignment based robust QSAR model based on a data set of strikingly diverse MEK4 inhibitors. We computed the electrostatic potential (ESP) charges using a density functional theory (DFT) formalism of the donor and acceptor atoms of the ligands and hinge residues. Novel descriptors were then generated from the perturbation of the charge densities of the donor and acceptor atoms and were used to model a diverse set of 84 compounds, from which we built a robust predictive model.

A Phase I Trial of Berberine in Chinese with Ulcerative Colitis

The Chinese natural product, berberine, has biological properties that support its potential efficacy as a colon cancer prevention agent. Its longstanding use in China to treat gastrointestinal tract and rheumatologic disorders is generally regarded as safe, supporting initial investigations in an at-risk population, such as individuals with ulcerative colitis. However, the safety of berberine in this population is not established. Individuals living in China with biopsy-proven ulcerative colitis, ≤grade 2 dysplasia, and with a ulcerative colitis disease activity index (UCDAI) score ≤1 on mesalamine, were randomized 3:1 in a double-blind phase I trial to berberine 900 mg/day or placebo for 3 months, with the primary objective of assessing safety. Blood samples and biopsies of the colorectum, from prespecified locations, were collected prior to and following therapy. Secondary endpoints included changes in UCDAI score, and in tissue and plasma markers of inflammation. Of toxicities at least possibly related, one episode of grade 3 elevation in transaminases and one episode of grade 1 nausea were observed among 12 individuals on berberine, and none were observed among 4 on placebo. The mean plasma berberine concentration was 3.5 nmol/L after berberine treatment, significantly higher than 0.5 nmol/L with placebo. Berberine significantly decreased the Geboes grade in colonic tissue, but had a nonsignificant effect on other tissue or blood biomarkers related to cell growth and inflammation. The combination of berberine and mesalamine is well tolerated in Chinese with ulcerative colitis and may enhance mesalamine's anti-inflammatory effects in colonic tissue.

A Multifunctional Therapy Approach for Cancer: Targeting Raf1- Mediated Inhibition of Cell Motility, Growth, and Interaction with the Microenvironment

Prostate cancer cells move from their primary site of origin, interact with a distant microenvironment, grow, and thereby cause death. It had heretofore not been possible to selectively inhibit cancer cell motility. Our group has recently shown that inhibition of intracellular activation of Raf1 with the small-molecule therapeutic KBU2046 permits, for the first time, selective inhibition of cell motility. We hypothesized that simultaneous disruption of multiple distinct functions that drive progression of prostate cancer to induce death would result in advanced disease control. Using a murine orthotopic implantation model of human prostate cancer metastasis, we demonstrate that combined treatment with KBU2046 and docetaxel retains docetaxel's antitumor action, but provides improved inhibition of metastasis, compared with monotherapy. KBU2046 does not interfere with hormone therapy, inclusive of enzalutamide-mediated inhibition of androgen receptor (AR) function and cell growth inhibition, and inclusive of the ability of castration to inhibit LNCaP-AR cell outgrowth in mice. Cell movement is necessary for osteoclast-mediated bone degradation. KBU2046 inhibits Raf1 and its downstream activation of MEK1/2 and ERK1/2 in osteoclasts, inhibiting cytoskeleton rearrangement, resorptive cavity formation, and bone destruction in vitro, with improved effects observed when the bone microenvironment is chemically modified by pretreatment with zoledronic acid. Using a murine cardiac injection model of human prostate cancer bone destruction quantified by CT, KBU2046 plus zoledronic exhibit improved inhibitory efficacy, compared with monotherapy. The combined disruption of pathways that drive cell movement, interaction with bone, and growth constitutes a multifunctional targeting strategy that provides advanced disease control.

Rapid fabrication of vascularized and innervated cell-laden bone models with biomimetic intrafibrillar collagen mineralization

Bone tissue, by definition, is an organic–inorganic nanocomposite, where metabolically active cells are embedded within a matrix that is heavily calcified on the nanoscale. Currently, there are no strategies that replicate these definitive characteristics of bone tissue. Here we describe a biomimetic approach where a supersaturated calcium and phosphate medium is used in combination with a non-collagenous protein analog to direct the deposition of nanoscale apatite, both in the intra- and extrafibrillar spaces of collagen embedded with osteoprogenitor, vascular, and neural cells. This process enables engineering of bone models replicating the key hallmarks of the bone cellular and extracellular microenvironment, including its protein-guided biomineralization, nanostructure, vasculature, innervation, inherent osteoinductive properties (without exogenous supplements), and cell-homing effects on bone-targeting diseases, such as prostate cancer. Ultimately, this approach enables fabrication of bone-like tissue models with high levels of biomimicry that may have broad implications for disease modeling, drug discovery, and regenerative engineering.

Bone tissue is a complex organic-inorganic nanocomposite and strategies that replicate the characteristics of bone tissue are scarce. Here the authors demonstrate the deposition of nanoscale apatite in collagen embedded with mesenchymal, vascular and nerve cells, using a protein-guided biomineralization approach.

Genistein treatment duration effects biomarkers of cell motility in human prostate

BACKGROUND

Long term dietary consumption of genistein by Chinese men is associated with decreased PCa metastasis and mortality. Short term treatment of US men with prostate cancer (PCa) with genistein decreases MMP-2 in prostate tissue. MEK4 regulates MMP-2 expression, drives PCa metastasis, and genistein inhibits MEK4, decreases MMP-2 expression and dietary dosing inhibits human PCa metastasis in mice. This study examines short- versus long-term treatment effects of genistein in humans and in vitro.

METHODS AND FINDINGS

US men with localized PCa were treated on a phase II trial with genistein (N = 14) versus not (N = 14) for one month prior to radical prostatectomy. Prostate epithelial cells were removed from fresh frozen tissue by laser capture microdissection, and the expression of 12,000 genes profiled. Genistein significantly altered the expression of four genes, three had established links to cancer cell motility and metastasis. Of these three, one was a non-coding transcript, and the other two were BASP1 and HCF2. Genistein increased BASP1 expression in humans, and its engineered over expression and knockdown demonstrated that it suppressed cell invasion in all six human prostate cell lines examined. Genistein decreased HCF2 expression in humans, and it was shown to increase cell invasion in all cell lines examined. The expression of MMP-2, MEK4 and BASP1 was then measured in formalin fixed prostate tissue from N = 38 Chinese men living in China and N = 41 US men living in the US, both cohorts with localized PCa. MMP-2 was 52% higher in Chinese compared to US tissue (P < 0.0001), MEK4 was 48% lower (P < 0.0001), and BASP1 was unaltered. Treatment of PC3 human PCa cells in vitro for up to 8 weeks demonstrated that short term genistein treatment decreased MMP-2, while long term treatment increased it, both changes being significant (P<0.05) compared to untreated control cells. Long term genistein-treated cells retained their responsiveness to genistein's anti-motility effect.

CONCLUSIONS

Genistein inhibits pathways in human prostate that drive transformation to a lethal high motility phenotype. Long term treatment induces compensatory changes in biomarkers of efficacy. The current strategy of using such biomarkers after short term intervention as go/no-go determinants in early phase chemoprevention trials should be carefully examined.

Synthesis and Biological Evaluation of 3-Arylindazoles as Selective MEK4 Inhibitors

Herein we report the discovery of a novel series of highly potent and selective mitogen-activated protein kinase kinase 4 (MEK4) inhibitors. MEK4 is an upstream kinase in MAPK signaling pathways that phosphorylates p38 MAPK and JNK in response to mitogenic and cellular stress queues. MEK4 is overexpressed and induces metastasis in advanced prostate cancer lesions. However, the value of MEK4 as an oncology target has not been pharmacologically validated because selective chemical probes targeting MEK4 have not been developed. Optimization of this series via structure-activity relationships and molecular modeling led to the identification of compound 6 ff (4-(6-fluoro-2H-indazol-3-yl)benzoic acid), a highly potent and selective MEK4 inhibitor. This series of inhibitors is the first of its kind in both activity and selectivity and will be useful in further defining the role of MEK4 in prostate and other cancers.

Whole-body Imaging of Cell Death Provides a Systemic, Minimally Invasive, Dynamic, and Near-real Time Indicator for Chemotherapeutic Drug Toxicity

PURPOSE

Response to toxicity in chemotherapies varies considerably from tissue to tissue and from patient to patient. An ability to monitor the tissue damage done by chemotherapy may have a profound impact on treatment and prognosis allowing for a proactive management in understanding and mitigating such events. For the first time, we investigated the feasibility of using whole-body imaging to map chemotherapeutic drug-induced toxicity on an individual basis.

EXPERIMENTAL DESIGN

In a preclinical proof-of-concept, rats were treated with a single clinical dose of cyclophosphamide, methotrexate, or cisplatin. In vivo whole-body imaging data were acquired using ^99mTc-duramycin, which identifies dead and dying cells as an unambiguous marker for tissue injury in susceptible organs. Imaging results were cross-validated using quantitative ex vivo measurements and histopathology and compared with standard blood and serum panels for toxicology.

RESULTS

The in vivo whole-body imaging data detected widespread changes, where spatially heterogeneous toxic effects were identified across different tissues, within substructures of organs, as well as among different individuals. The signal changes were consistent with established toxicity profiles of these chemotherapeutic drugs. Apart from generating a map of susceptible tissues, this in vivo imaging approach was more sensitive compared with conventional blood and serum markers used in toxicology. Also, repeated imaging during the acute period after drug treatment captured different kinetics of tissue injury among susceptible organs in males and females.

CONCLUSIONS

This novel and highly translational imaging approach shows promise in optimizing therapeutic decisions by detecting and managing drug toxicity on a personalized basis.Toxicity to normal tissues is a significant limitation in chemotherapies. This work demonstrated an in vivo imaging-based approach for characterizing toxicity-induced tissue injury in a systemic, dynamic, and near-real time fashion. This novel approach shows promise in optimizing therapeutic decisions by monitoring drug toxicity on a personalized basis.

Abstract 1560: Real-time monitoring of solid tumor progression by circulating stromal cells from early- to late-stage disease

Background: Blood-based biomarkers (PSA, CEA, CA125) are used to track real-time progression of disease in parallel with imaging. However, while numerous blood biomarkers exist, they are specific to cancer type (i.e., PSA to prostate and CEA to colon) and may not appear in all diseased individuals. Recently, cancer-associated macrophage-like cells (CAMLs), a circulating stromal cell subtype, were identified in various solid cancer types, which were observed increasing in size and in hyperploidy during progressive disease. To assess whether CAML enlargement is a biomarker of progression/response, we tracked CAML growth/shrinkage in a pilot study of patients (n=34). Blood was drawn from patients with lung, prostate, or breast cancers over a 3-month period, baseline through 2 treatment cycles, followed by continued monitoring for 2 years. These data suggest that morphologic assessment of CAMLs (growth/hyperploidy) appear to parallel cancer progression, or response to treatment, in multiple solid tumors.

Methods: A prospective multi-institutional study used anonymized peripheral blood samples from 34 cancer patients undergoing therapy [stage I (n=2), II (n=3), III (n=8) & IV (n=21)] with breast (n=10), lung (n=16), & prostate (n=8). Samples were taken prior to therapy (BL), at 1 month (FU1) follow-up and a 3-month (FU2) follow-up, after induction of therapy. Blood was processed by the CellSieve™ microfiltration technique at 4 institutions and stained for cytokeratin 8, 18 and 19, CD14 and CD45. After identification and quantification, CAMLs were measured based on their hyperploidy and cell size.

Results: CAMLs were found in 97% of cancer patients at BL, 97% at FU1 and 91% of FU2. Over the 2-year follow-up, 7 patients showed no signs of clinical disease progression, while 27 patients had observable progression. Of the 7 patients who did not progress, only two had CAMLs of ≥50µm at BL and at FU1, but whose CAMLs shrunk to &lt;50 µm by FU2. Of the 27 patients who progressed, 22 patients had ≥50µm CAMLs at all time points, while 5 patients had small &lt;50µm CAMLs at BL. Interestingly, CAMLs in these 5 patients had enlarged to ≥50µm by the FU2 time point.

Conclusions: We show that increased polynucleation and CAML enlargement indicate shorter progression-free survival in a number of cancer types after baseline. By monitoring CAML changes over time for the 34 individual patients, we demonstrated correlation of ongoing progression, or response, in tumors to the enlargement or shrinkage in CAMLs at follow-up time points from treatment induction. This pilot study suggests that CAMLs have the potential to monitor the progression/regression of malignancy in real time and suggests the need for larger validation studies.

Citation Format: Daniel L. Adams, Raymond Bergan, Martin J. Edelman, Stuart S. Martin, Rena Lapidus, Saranya Chumsri, Cha-Mei Tang, Steven H. Lin. Real-time monitoring of solid tumor progression by circulating stromal cells from early- to late-stage disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1560.

Abstract 3296: SMMART: Serial measurements of molecular and architectural responses to therapy

SMMART is a precision medicine research program focused on understanding the evolution of actionable biology and mechanisms of resistance in human tumors during therapy. This is accomplished through in depth functional, ‘omic and multiscale image analysis of longitudinal samples acquired during treatment. Here we present a case report detailing the insights that can be gained from the comparative analysis of pre- and post-treatment biopsy specimens in a late-stage metastatic breast cancer patient. To understand the molecular evolution of cancer, we interrogated genomics with targeted and whole exome sequencing, transcriptomics with RNA and gene-fusion sequencing, and proteomics with reverse phase protein arrays. To understand cellular organization and architectural changes, we employed multi-scale imaging tools, including scanning electron microscopy (SEM), cyclic immunofluorescence, immune cell profiling with cyclic immunohistochemistry, and traditional pathological assessment. During the course of treatment, we monitored patient response to therapy with clinical imaging, circulating tumor DNA sequencing and cancer protein assessment.

Individual assays revealed key aspects of how this individual's cancer evolved under therapeutic pressure. For example, mutational profiling revealed the patterns of clonal evolution and the acquisition of new genetic driver events. 2D and 3D SEM showed changes in ECM organization, macropinocytosis, mitochondrion size, number and density and number and organization of filopodia-like protrusions. We used a 30-color cyclic immunofluorescence analysis to identify differences in cancer cell proliferation and differentiation state, as well as the composition and organization of infiltrating immune cells. In addition, integrative analyses of multiple data types provided insight into the evolution of actionable biology within this patient's disease. This included changes in the suitability of the patient for immune checkpoint inhibitors as well as specific tyrosine kinase inhibitors. The comprehensive molecular and architectural characterization of an individual patient's cancer at multiple time points provides biologically novel and clinically relevant insight into the ways in which cancers become resistant to treatment.

Citation Format: Brett Johnson, Jamie Keck, Max Morris, Kiara Siex, Annette Kolodzie, Swapnil Parmar, Jessica Riesterer, Koei Chin, Summer Gibbs, Laura Heiser, Paul Spellman, Kyle Ellrott, Ozgun Babur, Emek Demir, Adam Margolin, Jeremy Goecks, Lisa Coussens, Raymond Bergan, Joe Gray. SMMART: Serial measurements of molecular and architectural responses to therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3296.

Precision therapeutic targeting of human cancer cell motility

Increased cancer cell motility constitutes a root cause of end organ destruction and mortality, but its complex regulation represents a barrier to precision targeting. We use the unique characteristics of small molecules to probe and selectively modulate cell motility. By coupling efficient chemical synthesis routes to multiple upfront in parallel phenotypic screens, we identify that KBU2046 inhibits cell motility and cell invasion in vitro. Across three different murine models of human prostate and breast cancer, KBU2046 inhibits metastasis, decreases bone destruction, and prolongs survival at nanomolar blood concentrations after oral administration. Comprehensive molecular, cellular and systemic-level assays all support a high level of selectivity. KBU2046 binds chaperone heterocomplexes, selectively alters binding of client proteins that regulate motility, and lacks all the hallmarks of classical chaperone inhibitors, including toxicity. We identify a unique cell motility regulatory mechanism and synthesize a targeted therapeutic, providing a platform to pursue studies in humans.

In this study, the authors identify and validate a halogen-substituted isoflavanone able to inhibit prostate cancer cell motility, invasion and metastasis in vitro and in vivo. They demonstrate its ability to selectively inhibit activation of client proteins that stimulate cell motility.

The Role of Cruciferous Vegetables and Isothiocyanates for Lung Cancer Prevention: Current Status, Challenges, and Future Research Directions

Lung cancer remains a leading cause of cancer-related deaths in the United States. Although smoking and air pollution exposure are primary risk factors of lung cancer, diet has also been reported to contribute to lung cancer risk. Cruciferous vegetables contain many bioactive compounds that alter the detoxification process of air-borne carcinogenic compounds and, thereby, may decrease lung cancer risk. In the meta-analysis of 31 observational studies, cruciferous vegetable intake is inversely associated with lung cancer risk (summary odds ratio/relative risk = 0.81 and 95% confidence interval = 0.74-0.89 for comparing the highest with lowest intake categories). More observational studies need to measure urinary isothiocyanate (ITC) concentrations and investigate their association with lung cancer risk in populations with relatively high intake of cruciferous vegetables. Current evidence is limited to two phase 2 clinical trials with incomplete reporting. Hence, more short-term clinical phase 2 trials need to examine effects of various amounts and types of cruciferous vegetables on biomarkers of risk and efficacy before a large phase 3 trial can be conducted to assess effects upon lung cancer risk. This would help further elucidate whether the inverse association observed with self-reported cruciferous vegetable intake is indeed due to ITC content or other bioactive compounds.

Prevention of colonic neoplasia with polyethylene glycol: A short term randomized placebo-controlled double-blinded trial

Chemoprevention represents an attractive modality against colorectal cancer (CRC) although widespread clinical implementation of promising agents (e.g. aspirin/NSAIDS) have been stymied by both suboptimal efficacy and concerns over toxicity. This highlights the need for better agents. Several groups, including our own, have reported that the over-the-counter laxative polyethylene glycol (PEG) has remarkable efficacy in rodent models of colon carcinogenesis. In this study, we undertook the first randomized human trial to address the role of PEG in prevention of human colonic neoplasia. This was a double-blind, placebo-controlled, three-arm trial where eligible subjects were randomized to 8g PEG-3350 (n = 27) or 17g PEG-3350 (n = 24), or placebo (n = 24; maltodextrin) orally for a duration of six months. Our initial primary endpoint was rectal aberrant crypt foci (ACF) but this was changed during protocol period to rectal mucosal epidermal growth factor receptor (EGFR). Of the 87 patients randomized, 48 completed study primary endpoints and rectal EGFR unchanged PEG treatment. Rectal ACF had a trend suggesting potentially reduction with PEG treatment (pre-post change 1.7 in placebo versus -0.3 in PEG 8+ 17g doses, p = 0.108). Other endpoints (proliferation, apoptosis, expression of SNAIL and E-cadherin), previously noted to be modulated in rodent models, appeared unchanged with PEG treatment in this clinical trial. We conclude that PEG was generally well tolerated with the trial failing to meet primary efficacy endpoints. However, rectal ACFs demonstrated a trend (albeit statistically insignificant) for suppression with PEG. Moreover, all molecular assays including EGFR were unaltered with PEG underscoring issues with lack of translatability of biomarkers from preclinical to clinical trials. This data may provide the impetus for future clinical trials on PEG using more robust biomarkers of chemoprevention.

Trial registration: ClinicalTrials.gov NCT00828984

Abstract 3798: Multiplex phenotyping of circulating cancer associated macrophage-like cells in patients with solid tumors

Background: Circulating cancer associated macrophage-like cells (CAMLs) are cancer specific giant cells circulating in the blood of patients with solid tumors. Since their discovery, few studies have been done to elucidate their lineage or phenotypic identity. The difficulty in classifying CAMLs is exemplified by their expression of multiple heterogeneous markers that defy conventional identification. Recently, we described a restaining method (QUAS-R) to screen individual cells using an array of up to 15 biomarkers. We used this method to screen CAMLs isolated from 152 cancer patient samples in 4 types of solid tumors to classify CAMLs by phenotypic immunostaining. These data suggest that CAMLs are a morphologically diverse and phenotypically heterogeneous population of cancer specific giant cells with overlapping myeloid, epithelial, and endothelial phenotypes.

Methods: This multi-institutional study used peripheral blood samples from 152 cancer patients (stage I-IV) from breast (n=42), lung (n=39), renal cell carcinoma (36) and prostate (n=35). Blood was processed by the CellSieve™ microfiltration technique at 5 institutions and stained for cytokeratin 8, 18 & 19, EpCAM, and CD45. After identification/imaging, the QUAS-R (Quench, Underivatize, Amine-Strip and Restain) technique was used to quench fluorescence signal of cells and then restain with vimentin/CD146/CD144, CD14/CD11b/CD41, CD11c/CD68/TIE2, or CD34/CD41/CD61. After staining, QUAS-R was again used to remove the fluorescence and samples restained with a third panel. Each patient sample was stained, quenched and restained with the above mentioned panels.

Results: In agreement with a number of studies, CAMLs were found in 86% of cancer patients (n=131/152), with increased detection from stage 1 (71%), followed by stage 2 (94%), stage 3 (88%) to stage 4 (88%). Breast cancer had the most CAMLs per sample (14.1 cells/7.5mL), followed by prostate (6.8), renal cell carcinoma (4.9) and lung (3.2). CD34 was most prevalent, found on 88% of CAMLs, followed by cytokeratin (81%), CD41 (79%), CD61 (78%), CD45 (75%), CD14 (72%), vimentin (63%), EpCAM (56%), CD146 (53%), CD68 (44%), CD11c (38%), TIE-2 (25%) and CD11b (0%). Based on our results, CAMLs seem to express overlapping phenotypes from a variety of lineages i.e. macrophage (CD14/CD68/CD11c), epithelial (cytokeratin/EpCAM), endothelial (CD146/TIE-2) and megakaryocyte (CD41/CD61).

Conclusions: Although identification of CAMLs is straightforward by morphological criteria (size and nuclear profile), their identification and lineage remains undetermined. We report the first mass screening of CAMLs to determine phenotypic expression. These data suggest that CAMLs cannot be grouped into any known cell subtype based on their expression profiles and represent a heterogeneous and variably differentiated population whose biological consequences in cancer remain under investigation.

Citation Format: Daniel L. Adams, R Katherine Alpaugh, Thai H. Ho, Steven H. Lin, Jeffrey R. Marks, Raymond Bergan, Stuart S. Martin, Saranya Chumsri, Cha-Mei Tang, Massimo Cristofanilli. Multiplex phenotyping of circulating cancer associated macrophage-like cells in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3798. doi:10.1158/1538-7445.AM2017-3798

Abstract 778: Identifying, subtyping and classifying tumor associated circulating endothelial cells in patients with solid tumors

Background: Tumor endothelial cells (ECs) are a population of stromal cells required for tumor growth that cooperate with tumors to form angiogenic structures. In blood, circulating ECs (CECs) are normal constituents of healthy individuals, although a Cancer Associated Vascular Endothelial cell (CAVE) subtype has been observed in cancer patients. The CAVE population has been isolated and identified using their large size or multicellular clustering and a pooled mixture of classical EC markers (i.e. CD31 and CD146). However, there has been no attempt to differentiate CAVEs from the many EC subtypes. This is not surprising as in-depth phenotyping of ECs requires an array of biomarkers that until recently has not been feasible. A multi-phenotypic screening of EC markers was tested on CAVEs from 116 blood samples in 3 types of solid tumors. This data suggests that CAVEs exist as a common and diverse subtype of tumor derived CECs that may express cytokeratin (CK) and various EC biomarkers, correlating to disease stage.

Methods: Peripheral blood samples from 116 cancer patients (stage I-IV) were drawn from 2012-2014 including breast (n=42), lung (n=39) and prostate (n=35), as well as blood from 34 healthy controls. Blood was processed by an established filtration approach, i.e. the CellSieveTM microfiltration technique (Creatv MicroTech), filtering blood by size exclusion and staining cells for CK 8, 18 & 19, EpCAM and CD45. After identification and imaging, the QUAS-R (Quench, Underivatize, Amine-Strip and Restain) technique was used to remove fluorescence signal and restain all cells with CD31, CD146, CD144, & DAPI. After reimaging, QUAS-R was again used to remove fluorescence and restain the cells for CD14, CD105, CD34, & DAPI.

Results: Out of 116 patient samples, we identified CAVEs in 63 patients (54%) based on positivity of CD31, CD144 or CD146, but none were found in healthy controls. CAVEs per 7.5mL sample in patients averaged 5.1 (breast), 5.6 (prostate) and 7.9 (lung). Presence of CAVEs appeared related to stage with 26% in stage 1, 61% in stage 2, 68% in stage 3, and 74% in stage 4 patients. No CAVEs were positive for CD14 or CD45. CD31 was the most present marker, found on 93% of CAVEs, followed by CD144 (85%), CD34 (64%), CD146 (45%), & CD105 (4%). In contrast with the previous study on this topic, CK was found in 67% of CAVEs, but was not a universal marker.

Conclusions: It has been reported that CK+ and CD45- CECs are isolated from the blood of cancer patients in colon and lung cancers, prompting some to classify them as circulating tumor cells. However, subtyping these CECs is incomplete when characterized with only 3-4 biomarkers. A multi-phenotypic subtyping technique was used to properly identify and subtype these CECs in cancer patients. This data suggest that a subset of CECs, e.g. CAVEs, are found in circulation as CK+/CD45-, but exist as a heterogeneous population of cancer specific circulating cells that require further study.

Citation Format: Daniel L. Adams, R. Katherine Alpaugh, Steven H. Lin, Jeffrey R. Marks, Raymond Bergan, Stuart S. Martin, Sarany Chumsri, Massimo Cristofanilli, Cha-Mei Tang, Steingrimur Stefansson. Identifying, subtyping and classifying tumor associated circulating endothelial cells in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 778. doi:10.1158/1538-7445.AM2017-778

A Chemical Probe Strategy for Interrogating Inhibitor Selectivity Across the MEK Kinase Family

MEK4 is an upstream kinase in MAPK signaling pathways where it phosphorylates p38 MAPK and JNK in response to mitogenic and cellular stress queues. MEK4 is overexpressed and induces metastasis in advanced prostate cancer lesions. However, the value of MEK4 as an oncology target has not been pharmacologically validated because selective chemical probes targeting MEK4 have not been developed. Despite a high level of sequence homology in the ATP-binding site, most reported MEK inhibitors are selective for MEK1/2 and display reduced potency toward other MEKs. Here, we present the first functional and binding selectivity-profiling platform of the MEK family. We applied the platform to profile a set of known kinase inhibitors and used the results to develop an in silico approach for small molecule docking against MEK proteins. The docking studies identified molecular features of the ligands and corresponding amino acids in MEK proteins responsible for high affinity binding versus those driving selectivity. WaterLOGSY and saturation transfer difference (STD) NMR spectroscopy techniques were utilized to understand the binding modes of active compounds. Further minor synthetic manipulations provide a proof of concept by showing how information gained through this platform can be utilized to perturb selectivity across the MEK family. This inhibitor-based approach pinpoints key features governing MEK family selectivity and clarifies empirical selectivity profiles for a set of kinase inhibitors. Going forward, the platform provides a rationale for facilitating the development of MEK-selective inhibitors, particularly MEK4 selective inhibitors, and repurposing of kinase inhibitors for probing the structural selectivity of isoforms.

Selenomethionine and methyl selenocysteine: multiple-dose pharmacokinetics in selenium-replete men

According to the Nutritional Prevention of Cancer (NPC) trial, a selenized yeast supplement containing selenium, 200 mcg/day, decreased the incidence of total cancer, cancers of the prostate, colon and lung, and cancer mortality. The active agent in the selenized yeast supplement was assumed to be selenomethionine (SEMET), although the supplement had not been well speciated. The SELECT study, largely motivated by the NPC trial, enrolling nearly 40 times as many subjects, showed unequivocally that selenium 200 mcg/day, with selenium in the form of SEMET, does not protect selenium-replete men against prostate or other major cancer. The agent tested by SELECT, pure SEMET, could have been different from the selenized yeast tested in NPC. One of the selenium forms suspected of having chemopreventive effects, and which may have been present in the NPC agent, is methyl selenocysteine (MSC). This study, with 29 selenium-replete patients enrolled in a randomized, double-blind trial, compared the multiple-dose toxicity, pharmacokinetics and pharmacodynamics of MSC and SEMET. Patients were on trial for 84 days. No toxicity was observed. Although SEMET supplementation increased blood selenium concentration more than MSC did, neither form had a more than minimal impact on the two major selenoproteins: selenoprotein P(SEPP1) and glutathione peroxidase(GPX).

A Way Forward for Cancer Chemoprevention: Think Local

As cells progress through carcinogenesis, the associated exponential expansion of genetic and molecular aberrations and resultant heterogeneity make therapeutic success increasingly unattainable. Therapeutic intervention at early stages of carcinogenesis that occurs within the primary organ and in the face of a lower burden of molecular aberrations, constitutes a basic tenet of cancer chemoprevention, and provides a situation that favors a greater degree of therapeutic efficacy compared with that of advanced cancer. A longstanding barrier to chemoprevention relates to the requirement for essentially no systemic toxicity, and the fact that when large numbers of people are treated, the emergence of systemic toxicity is almost universal. A rational means to address this in fact relates to a second basic tenet of the chemopreventive strategy: the focus of therapeutic intervention is to disrupt a process that is in essence localized to a single organ. Based upon this consideration, a strategy which is based upon local delivery of therapeutics to an at-risk organ will achieve therapeutic efficacy while avoiding systemic delivery and its associated toxicity. This article will review the rationale for undertaking such an approach, describe successful clinical achievements based on this strategy, describe ongoing efforts to expand the impact of this approach, and together will highlight the high impact that this approach has already had on the field as well as its extremely high potential for future impact. Cancer Prev Res; 10(1); 14-35. ©2016 AACR.

A randomized phase II presurgical trial of transdermal 4-hydroxytamoxifen gel versus oral tamoxifen in women with ductal carcinoma in situ of the breast

PURPOSE

Local transdermal therapy to the breast may achieve effective target-organ drug delivery, while diminishing systemic effects. We conducted a randomized, double-blind, placebo-controlled phase II trial comparing transdermal 4-hydroxytamoxifen gel (4-OHT) to oral tamoxifen (oral-T) in women with ductal carcinoma in situ (DCIS).

METHODS

Twenty-seven pre- and postmenopausal women were randomized to 4-OHT (4 mg/day) or oral-T (20 mg/day) for 6 to 10 weeks before surgery. Plasma, nipple aspirate fluid, and breast adipose tissue concentrations of tamoxifen and its major metabolites were determined by liquid chromatography/tandem mass spectrometry. The primary endpoint was Ki67 labeling in DCIS lesions, measured by immunohistochemistry. In plasma, insulin-like growth factor-1 (IGFI), sex hormone-binding globulin (SHBG), and coagulation protein concentrations were determined.

RESULTS

Posttherapy Ki67 decreased by 3.4% in the 4-OHT and 5.1% in the oral-T group (P ≤ 0.03 in both, between-group P = 0. 99). Mean plasma 4-OHT was 0.2 and 1.1 ng/mL in 4-OHT and oral groups, respectively (P = 0.0003), whereas mean breast adipose tissue concentrations of 4-OHT were 5.8 ng/g in the 4-OHT group and 5.4 ng/g in the oral group (P = 0.88). There were significant increases in plasma SHBG, factor VIII, and von Willebrand factor and a significant decrease in plasma IGFI with oral-T, but not with 4-OHT. The incidence of hot flashes was similar in both groups.

CONCLUSIONS

The antiproliferative effect of 4-OHT gel applied to breast skin was similar to that of oral-T, but effects on endocrine and coagulation parameters were reduced. These findings support the further evaluation of local transdermal therapy for DCIS and breast cancer prevention.

Improving diversity in cancer research trials: the story of the Cancer Disparities Research Network

The participation of racial and ethnic minorities and underserved populations in clinical trials is a critical link between scientific innovation and improvements in health care delivery and health outcomes. However, these population groups continue to be underrepresented in research. We describe the development of the Cancer Disparities Research Network (CDRN) to improve minority and underserved populations' participation in biobanking research. Between February and October 2011, we conducted a regional assessment to identify challenges and opportunities for cancer trials and biobanking research across the CDRN. Representatives from ten CDRN biorepository facilities completed an online survey assessing their facilities' minority biospecimen collection, biobanking practices, and education/outreach initiatives. Representatives of eight facilities also participated in stakeholder interviews. The majority (70%) of facilities reported that specimens were available for research, although only one tenth of these specimens were from non-White patients. Most facilities collected a patient's age, gender, race, medical history, and ethnicity with samples; however, less than half also collected family health history, education level, household income, or primary language spoken. In addition, few institutions collected Asian or Hispanic subgroup information. Only a few reported biospecimen collection outreach programs specifically targeting minority and underserved populations. Biospecimen directors and administrators indicated that funding, biospecimen sharing procedures, and standardization barriers limited their facilities from collaborating in biospecimen collection programs, despite their great interest. These findings suggest that the CDRN can provide opportunities for collaboration, resource sharing, and fostering of research ideas to address cancer disparities in biospecimen research.

Recruitment strategy cost and impact on minority accrual to a breast cancer prevention trial

BACKGROUND

Recruitment of minorities to cancer prevention trials is difficult and costly. Early-phase cancer prevention trials have fewer resources to promote recruitment. Identifying cost-effective strategies that can replace or supplement traditional recruitment methods and improve minority accrual to small, early-phase cancer prevention trials are of critical importance.

PURPOSE

To compare the costs of accrual strategies used in a small breast cancer prevention trial and assess their impact on recruitment and minority accrual.

METHODS

A total of 1196 potential subjects with a known recruitment source contacted study coordinators about the SOY study, a breast cancer prevention trial. Recruitment strategies for this study included recruitment from within the Northwestern University network (internal strategy), advertisements placed on public transportation (Chicago Transit Authority (CTA)), health-related events, media (print/radio/television), and direct mail. Total recruitment strategy cost included the cost of study personnel and material costs calculated from itemized receipts. Incremental cost-effectiveness ratios (ICERs) were calculated to compare the relative cost-effectiveness of each recruitment strategy. If a strategy was more costly and less effective than its comparator, then that strategy was considered dominated. Scenarios that were not dominated were compared. The primary effectiveness measure was the number of consents. Separate ICERs were calculated using the number of minority consents as the effectiveness measure.

RESULTS

The total cost of SOY study recruitment was US$164,585, which included the cost of materials (US$26,133) and personnel (US$138,452). The internal referral strategy was the largest source of trial contacts (748/1196; 63%), consents (107/150; 71%), and minority consents (17/34; 50%) and was the most expensive strategy (US$139,033). CTA ads generated the second largest number of trial contacts (326/1196; 27%), the most minority contacts (184/321; 57%), and 16 minority consents (16/34; 47%), at a total cost of US$15,562. The other three strategies yielded many fewer contacts and consents. The methods of health events, CTA ads, and the internal strategy showed some evidence of cost-effectiveness (ICER: US$581, US$717, and US$1524, respectively). The CTA strategy was the most cost-effective strategy for minority accrual (ICER: US$908).

LIMITATIONS

Recall bias may have limited the accuracy of estimated time spent on recruitment by study personnel. Also, costs spent specifically on minority accrual were unobtainable; results may not be generalizable to other settings; and cost-effectiveness data for the methods of media, health events, and direct mail should be interpreted with caution since these methods generated few consents.

CONCLUSIONS

Public transportation ads have the potential to generate numerous minority contacts and consents at a reasonable cost within an urban setting. Combined with traditional methods of recruitment, this method can lead to timelier study completion and increased minority accrual. Future research should prospectively track recruitment and costs in order to better assess the cost-effectiveness of recruitment methods used to target minority populations.

Abstract P1-09-07: Topical 4-OHT trial in women with DCIS of the breast: report of plasma and breast tissue concentration of tamoxifen metabolites

Background: Earlier studies have shown that 1–2mg of 4-hydroxytamoxifen (4–OHT) gel applied to the breast skin reduced cell proliferation in estrogen receptor (ER) positive invasive cancers to a similar degree as oral tamoxifen (TAM), with significantly lower plasma levels. We now report results of a Phase IIB pre-surgical window trial of women with DCIS, designed to obtain pilot data in early lesions. Our ultimate goal is to develop transdermal 4-OHT as an alternative to oral TAM for women at high risk for breast cancer and those with DCIS. The study was closed early because the manufacturer discontinued the drug supply, but remains blinded until all biomarker analysis is complete. Here we report the plasma and breast adipose tissue concentration of TAM metabolites from the topical 4-OHT gel group (4 mg) in comparison with the oral TAM group (20mg).

Methods: Women with DCIS were enrolled, and randomized to 4-OHT gel (4mg/day, 2mg per breast, E: Z isomers = 1:1,) or to oral (Z) TAM (20mg/day) for 4–10 weeks before surgery. Blood was collected on the day of surgery, and breast adipose tissue was collected at surgery. There were a total of 22 patients with matched blood and breast adipose tissue. The concentration of TAM metabolites in plasma and breast tissue was determined with liquid chromatography/tandem mass spectrometry. We assumed that the subjects with detectable N-desmethyl TAM (NDT) in plasma belong to the oral TAM group because NDT is not a product of 4-OHT metabolism. Under this assumption, 13 subjects were categorized into oral TAM group, and 9 subjects into the topical 4-OHT group. Wilcoxon rank-sum test was used for statistical analysis.

Results: The results are shown in the table. The concentration is presented as mean ± SD; the lowest quantitation limit (LQL) was 1 ng/mL for plasma, and 3 ng/g for tissue. TAM and its metabolites were found in the plasma of the presumed oral TAM group, with high levels of TAM and NDT. In the presumed 4-OHT gel group, only (Z) 4-OHT was found in the plasma although both (E) and (Z) forms were applied. The mean plasma level of 4-OHT in the gel group was 70% lower than the mean of 4-OHT in the oral TAM group (p = 0.004). In breast tissue, similar amounts of (E) and (Z) forms of 4-OHT were found in the 4-OHT gel group, with the (Z) 4-OHT level being equivalent to that in the oral TAM group (p = 0.48). Endoxifen was only found in the oral TAM group. We saw no evidence of further metabolic transformation of 4-OHT in the breast following topical administration.

Methyl selenocysteine: single-dose pharmacokinetics in men

The recently published report of the SELECT evaluation of selenium and vitamin E provided strong evidence that selenium 200 μg per day in the form of selenomethionine does not protect selenium-replete men against prostate or any other cancer. This seems to refute the result of the much smaller Nutritional Prevention of Cancer (NPC) trial of selenium. Because SELECT did not test the NPC agent, it is possible that the difference between the two trials stems partly from the use of different agents: selenomethionine in SELECT, and selenized yeast in the NPC trial. One of the organic selenium forms suspected of having strong chemopreventive effects, and which may have been present in the NPC agent, is methyl selenocysteine. This study characterizes the single-dose pharmacokinetics of methyl selenocysteine.

Abstract B6: Region Five GMaP/BMaP Network: Preliminary findings from the comprehensive needs assessment biospecimen facility survey

Objective: The Region Five GMaP/BMaP Network is a regional partnership representing 18 NCI funded institutions charged with the implementation of a comprehensive needs assessment (CNAT). This presentation focuses on preliminary findings from the Biospecimen Facility Survey.

Methods: The CNAT consisted of a mixed methods approach utilizing four instruments: A principal Investigator Survey and PI Interview and a Biospecimen Facility Survey and Interview. The surveys were conducted online during the months of March/ April 2011. Interviews will be conducted in July. The goal of the biospecimen facility survey which is the focus of this abstract is to assess minority biospecimen collection, biobanking practices, education, and outreach initiatives. The biospecimen survey consisted of 14 distinct questions, with affiliated subset questions, across five areas. These questions captured details from the institutions’ core facilities and inventory human specimens that were available for research. The survey was completed online by 10 biospecimen facility administrators.

Results: Preliminary findings consistently reported disparities in biospecimen collection among minority populations. Eight out of ten facilities reported the types of cancer and racial and ethnic groups from whom they collected specimens. Upon close review of the data, gaps in specimens collected for populations with a high burden of cancer were commonly identified. Seven facilities reported having collected specimen from 116,417 White patients vs. 12,592 Non-White (minority) patients’ and 1648 Hispanic patients’. Tissue (diseased and healthy) was most commonly collected and bodily fluids were least commonly collected.

While 40% of the biospecimen facilities have collaborated on biospecimen education efforts, we have learned that 60% of these facilities have collaborated on projects that collect specimens for the study of health disparities. The data mirrors similar findings from the PI survey; over half of our PIs are involved in biospecimen education and minority collection efforts.

In reference to bioinformatics and electronic data systems we found that 100% of the Region Five facilities currently use electronic annotation systems for biospecimen collection. However, there is a wide range of data systems/platforms used across the institutions which raise issues of compatibility. Along with this, we have found that 94% of specimens collected by our facilities have associated pathology data available.

Biospecimen facility administrators identified barriers which limit them from collaborating in collection programs. However, they also indicated a high desire to collaborate.

Conclusions: There is a need to focus on minority biospecimen collection efforts and address the gaps in how race and ethnicity and subtypes of biospecimens are collected across our institutions. Region Five is exploring ways to share instruments and methodologies used to collect race and ethnicity and develop strategies to standardize patient information collected. We anticipate implementing Cancer 101 and 102 education and training on research participation, biospecimen donation/biobanking and genetics across our institutions. In addition, there are opportunities for collaboration among principal investigators and biospecimen facilities around minority specimen collection efforts.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B6.

Abstract 5244: Genistein's anti-invasion and anti-metastatic effects are linked to decreases in the expression of several different gene in Human prostate cancer that regulate metastatic behavior

Genistein has been shown by our group to inhibit Human prostate cancer (PCa) cell invasion in vitro and metastasis in vivo. Related studies demonstrate that endoglin (ENG), a TGF b superfamily receptor, suppresses invasion via activation of Smad 1, and that Genistein therapeutically compensated for endoglin loss by activating Smad 1 signaling. The mechanisms underlying these effects by Genistein are not clear. We hypothesized that they resulted from effects by genistein upon multiple genes that together regulate metastatic behavior.

Methods: PC3M cells were treated or not with 10uM Genistein × 3 days, RNA was isolated, treated with DNAse, and effects upon gene expression were screened for using SAbiosciences metastasis specific and extracellular matrix and adhesion molecule specific gene expression array platforms. Array experiments were performed 2-3 separate times. Positive array findings were then evaluated by real time qRT/PCR, using gene-specific primer/probe sets. These experiments were performed 3 separate times. A student's T-test P-value&lt;/= 0.05 was required.

Results: Genistein significantly decreased MMP2, MMP10 and MMP 13 by 2.81, 3.98 and 4.87 fold, respectively, on the metastasis array, and decreased MMP1, MMP10, MMP13 and SPARC (osteonectin) by 2.29, 3.25, 5.36 and 3.57 fold, respectively, on the matrix /adhesion array. With qRT/PCR, Genistein decreased MMP1, MMP2, MMP10, MMP13 and SPARC by 2.13, 2.17, 4.43, 6.82 and 2.57 fold, respectively. We then treated previously characterized stably engineered ENG human PCa cell lines. Hi-ENG, vector control (VC) and NO-ENG, with Genistein or not, followed by qRT/PCR, ENG expression did not alter gene expression in a consistent fashion. Importantly, ENG status had no effect upon Genistein's ability to decrease the expression of any of the five genes.

Conclusions: We demonstrate for the first time that Genistein inhibit MMP1, MMP2, MMP10, MMP13 and SPARC gene expression. Also, Genistein's effect upon these genes is not dependent upon the endoglin pathway. Further, endoglin does not appear to regulate these genes. Finally these data support the notion that Gensitein's anti-invasion and anti-metastatic actions result from effects upon several genes that together affect invasive and metastatic behavior.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5244. doi:10.1158/1538-7445.AM2011-5244

Abstract B58: Discovery of a novel drug KBU2046 that inhibits conversion of human prostate cancer to a metastatic phenotype

Epidemiological evidence, preclinical studies and prospective phase II studies in humans indicate that the isoflavone, genistein, will inhibit the conversion of human prostate cells to an invasive, and ultimately, a metastatic phenotype. Though promising, genistein exerts many additional effects that have the potential for future toxicity in humans. We therefore sought to discover a new drug with improved efficacy and most importantly, with high specificity. Starting from an isoflavone chemical scaffold, we employed a fragment-based chemical synthesis diversification approach, and coupled it to three in vitro screens: 1) cell invasion (efficacy), 2) cell growth inhibition (an indicator of general toxicity), and 3) several measures of estrogenic activity. From multiple synthesis/biological assay iterations we developed a refined structure-activity relationship map, thereby leading us to discover KBU2046. KBU2046 represents a new and chemically distinct class of bioactive compounds. It has greater anti-invasion efficacy than genistein, and more importantly, no cell toxicity or estrogenic activity. Extensive toxicity studies in mice were negative. At low nanomolar blood concentrations, KBU2046 will prevent orthotopically implanted human prostate cancer cells from forming metastasis in a dose-responsive fashion. In summary, we have successfully discovered and developed a compound that prevents progression to a metastatic phenotype for human prostate cancer. We are in the process of bringing KBU2046 into the clinic, with the goal of preventing death from the second most common cause of cancer related death in men.

Citation Information: Cancer Prev Res 2010;3(12 Suppl):B58.

Labeling TiO2 nanoparticles with dyes for optical fluorescence microscopy and determination of TiO2-DNA nanoconjugate stability

Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA nanoconjugates in malignant cells.

Abstract ED05-02: Discovering new drugs to inhibit prostate cancer metastasis

ED05-02

Cancer chemoprevention offers a unique drug discovery opportunity. This is because at its core, chemoprevention involves the interface between pharmacologic agents that induce perturbations in biological systems and early stage cancer biology. The molecular aberrations in early stage cancer are more limited than those in advanced stage cancer. This provides a more permissive environment for understanding the complex relationships between drug, pharmacologic target, and therapeutic result. Thus, agents with therapeutically relevant activity represent important investigative tools that can be used to reveal important underlying biology, to identify new pharmacologic targets, and to develop pathophysiologically relevant models. Initial agents can then serve as starting blocks for new chemical synthesis, and these new compounds in turn can be evaluated for bioactivity in relevant model systems. The same considerations in the field of chemoprevention that facilitate this conventional bench-to-man approach to drug discovery can also be applied to the more novel approach of beginning drug discovery endeavors in man. The impetus for undertaking such an approach stems from the facts that our preclinical models have severe restrictions in emulating the biology in man, that the transition from preclinical to clinical represents a frequent point of failure, that the time to drug approval is not improving, and that the cost of drug discovery continues to rise. With the advent of new methods that permit robust system-wide measurement of cell and molecular parameters on limiting amounts of tissue, a practical barrier to beginning drug discovery efforts in man is now being lifted. Here too, chemoprevention offers a unique opportunity. This is because chemopreventive agent candidates are relatively non-toxic, and because they are tested in well defined risk cohorts. Thus, taken together, it now becomes possible to prospectively administer relatively non-toxic agents to at risk cohorts, and to screen for cell and molecular effects in a target organ harboring a limited spectrum of molecular aberrations. By definition, the resultant findings will have direct relevance to man, as well as to relevant underlying biology. An example of how an integrated approach was pursued by a single research group will be provided, and will serve to highlight the efficiency of interfacing chemoprevention with drug discovery. In particular, a natural product that possesses anti-motility properties has fostered the elucidation of pathways which regulated prostate cancer cell motility, has led to the identification of a pharmacologically relevant target protein, and has provided the chemical scaffold which supported new agent discovery. By coupling administration of the natural product to man, with gene expression profiling of target cells in man, new regulators of prostate cell motility have been identified and then confirmed by in vitro studies.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):ED05-02.

A phase II study of single agent bortezomib in patients with metastatic breast cancer: a single institution experience

PS-341, now known as bortezomib (Velcade[Millenium Pharmaceuticals, Inc., Cambridge, MA; and Johnson & Johnson Pharmaceutical Research & Development, LLC, Spring house, PA]), is a proteasome inhibitor approved for the treatment of refractory multiple myeloma. Preclinical and early clinical studies showed PS-341 to be effective in solid tumors, one of which was breast cancer. We conducted a single institution, phase II study using PS-341 in the treatment of patients with metastatic breast cancer. The primary objective of this study was to determine the objective tumor response in patients with metastatic breast cancer (MBC) receiving PS-341. The secondary objectives were to estimate progression-free survival of patients receiving single-agent PS-341 and to evaluate toxicity related to PS-341. In all 12 patients who met criteria for enrollment, there were no observed objective responses. Further, all 12 patients progressed while receiving therapy with PS-341. This study was terminated after the first stage due to the lack of any objective response.

Gene expression profiling of renal medullary carcinoma

BACKGROUND

Renal medullary carcinoma is a rare kidney tumor with highly aggressive behavior. This tumor occurs exclusively in young patients with sickle cell trait or disease. To the authors' knowledge, very little is known to date regarding the underlying molecular genetics of this tumor, and no effective therapy has been established.

METHODS

The authors analyzed the gene expression profiles of 2 renal medullary carcinomas from patients with sickle cell trait using microarrays containing 21,632 cyclic DNA (cDNA) clones and compared them with the gene expression profiles of 64 renal tumors.

RESULTS

Based on global gene clustering with 3583 selected cDNAs, the authors found a distinct molecular signature of renal medullary carcinoma, which clustered closely with urothelial (transitional cell) carcinoma of the renal pelvis, rather than renal cell carcinoma (RCC). This finding of a significant difference in the gene expression patterns of renal medullary carcinoma compared with RCC suggests that this tumor should not be treated as a conventional RCC but, rather, as a special malignancy. This study also identified genes/proteins that may serve as biomarkers for renal medullary carcinoma or as potential targets of novel therapies. In addition, comparative genomic microarray analysis allowed the authors to predict the lack of chromosomal imbalances in this tumor.

CONCLUSIONS

To the authors' knowledge, the current study is the first molecular profiling of renal medullary carcinoma, a rare but highly aggressive kidney carcinoma. The genes that are expressed specifically in this tumor may lead to not only a better understanding of its molecular pathways and discoveries of novel diagnostic markers but also, more important, to effective therapeutic interventions.

A Phase I study of infusional vinblastine in combination with the P-glycoprotein antagonist PSC 833 (valspodar)

BACKGROUND

PSC 833 is a second-generation P-glycoprotein (Pgp) antagonist developed to reverse multidrug resistance (MDR). The authors conducted a Phase I study of orally administered PSC 833 in combination with vinblastine administered as a 5-day continuous infusion.

METHODS

Seventy-nine patients with advanced malignant disease were enrolled in the trial and treated with escalating doses of PSC 833. Pharmacokinetic interactions between PSC 833 and vinblastine were anticipated. Accordingly, when dose limiting toxicities were observed, the dose of vinblastine was reduced as PSC 833 was escalated. Three schedules and two formulations of PSC 833 were used in the study.

RESULTS

The maximum tolerated doses of PSC 833 were 12.5 mg/kg orally every 12 hours for 8 days for the liquid formulation in combination with 0.9 mg/m(2) per day vinblastine as a continuous intravenous infusion (CIV) for 5 days; and 4 mg/kg orally every 6 hours for 8 days for the microemulsion formulation in combination with 0.6 mg/m(2) per day vinblastine CIV for 5 days. The principal toxicities for PSC 833 were ataxia and paresthesias and for the combination, constipation, fever. and neutropenia. Increased oral bioavailability and increased peak and trough concentrations were observed with the microemulsion formulation. Significant interpatient variability in pharmacokinetic parameters was observed. Ten patients studied at the MTD for PSC 833 (4 mg/kg orally every 6 hours for 8 days) had inhibition of rhodamine efflux from CD56 positive peripheral lymphocytes as a surrogate for Pgp antagonism. Among 43 evaluable patients with clear cell carcinoma of the kidney, 3 patients had complete responses, and 1 patient had a partial response.

CONCLUSIONS

PSC 833 in combination with vinblastine can be administered safely to patients provided the vinblastine dose is adjusted for pharmacokinetic interactions. The high interpatient variability is a significant confounding factor. Surrogate studies with CD56 positive cells suggest that Pgp inhibition in the clinical setting is achievable. Improved methods for predicting pharmacokinetic interactions should improve future studies.