Pixelwise H-score: A novel digital image analysis-based metric to quantify membrane biomarker expression from immunohistochemistry images.

Immunohistochemistry (IHC) assays play a central role in evaluating biomarker expression in tissue sections for diagnostic and research applications. Manual scoring of IHC images, which is the current standard of practice, is known to have several shortcomings in terms of reproducibility and scalability to large scale studies. Here, by using a digital image analysis-based approach, we introduce a new metric called the pixelwise H-score (pix H-score) that quantifies biomarker expression from whole-slide scanned IHC images. The pix H-score is an unsupervised algorithm that only requires the specification of intensity thresholds for the biomarker and the nuclear-counterstain channels. We present the detailed implementation of the pix H-score in two different whole-slide image analysis software packages Visiopharm and HALO. We consider three biomarkers P-cadherin, PD-L1, and 5T4, and show how the pix H-score exhibits tight concordance to multiple orthogonal measurements of biomarker abundance such as the biomarker mRNA transcript and the pathologist H-score. We also compare the pix H-score to existing automated image analysis algorithms and demonstrate that the pix H-score provides either comparable or significantly better performance over these methodologies. We also present results of an empirical resampling approach to assess the performance of the pix H-score in estimating biomarker abundance from select regions within the tumor tissue relative to the whole tumor resection. We anticipate that the new metric will be broadly applicable to quantify biomarker expression from a wide variety of IHC images. Moreover, these results underscore the benefit of digital image analysis-based approaches which offer an objective, reproducible, and highly scalable strategy to quantitatively analyze IHC images.

First-in-Human Study of PF-06647020 (Cofetuzumab Pelidotin), an Antibody-Drug Conjugate Targeting Protein Tyrosine Kinase 7, in Advanced Solid Tumors.

PURPOSE: We investigated safety, tolerability, pharmacokinetics, and antitumor activity of the protein tyrosine kinase 7 (PTK7)-targeted, auristatin-based antibody-drug conjugate (ADC) PF-06647020/cofetuzumab pelidotin (NCT02222922). PATIENTS AND METHODS: Patients received PF-06647020 intravenously every 3 weeks at 0.2-3.7 mg/kg or every 2 weeks at 2.1-3.2 mg/kg, in sequential dose escalation, following a modified toxicity probability interval method. In dose expansion, pretreated patients with advanced, platinum-resistant ovarian cancer, non-small cell lung cancer (NSCLC), or triple-negative breast cancer (TNBC) received PF-06647020 2.8 mg/kg every 3 weeks. RESULTS: The most common, treatment-related adverse events for PF-06647020 administered every 3 weeks were nausea, alopecia, fatigue, headache, neutropenia, and vomiting (45%-25%); 25% of patients had grade ≥ 3 neutropenia. Two patients experienced dose-limiting toxicities (grade 3 headache and fatigue) at the highest every 3 weeks dose evaluated. The recommended phase II dose was 2.8 mg/kg every 3 weeks. The overall safety profile observed with PF-06647020 administered every 2 weeks was similar to that of the every 3 weeks regimen. Systemic exposure for the ADC and total antibody generally increased in a dose-proportional manner. Antitumor activity was observed in treated patients with overall objective response rates of 27% in ovarian cancer (n = 63), 19% in NSCLC (n = 31), and 21% in TNBC (n = 29). Responders tended to have moderate or high PTK7 tumor expression by IHC. CONCLUSIONS: This PTK7-targeted ADC demonstrated therapeutic activity in previously treated patients with ovarian cancer, NSCLC, and TNBC at a dose range of 2.1-3.2 mg/kg, supporting further clinical evaluation to refine dose, schedule, and predictive tissue biomarker testing in patients with advanced malignancies.

Ovarian cancer: new strategies and emerging targets for the treatment of patients with advanced disease.

Recently approved therapies have contributed to a significant progress in the management of ovarian cancer; yet, more options are needed to further improve outcomes in patients with advanced disease. Here we review the rationale and ongoing clinical trials of novel combination strategies involving chemotherapy, poly ADP ribose polymerase, programmed death 1 (PD-1)/PD-ligand 1 immune checkpoint and/or vascular endothelial growth factor receptor inhibitors. Further, we discuss novel agents aimed at targets associated with ovarian cancer growth or progression that are emerging as potential new treatment approaches. Among them, agents targeted to folate receptor α, tissue factor, and protein kinase-mediated pathways (WEE1 kinase, phosphatidylinositol-3 kinase α, cell cycle checkpoint kinase 1/2, ATR kinase) are currently in clinical development as mono- or combination therapies. If successful, findings from these extensive development efforts may further transform treatment of patients with advanced ovarian cancer.

Tobacco-Free Ambassador Partnership: Empowering Youth Advocates in Appalachian Communities.

Kentucky youth (14.3%) smoke more cigarettes as compared to the U.S. average (8.8%), and Appalachian communities suffer disproportionately from tobacco-related diseases such as lung cancer. Training youth to become advocates is an effective strategy to improve health equity. This article describes the development and impact of a youth advocacy program to promote tobacco control policies in Appalachian Kentucky. Phase I (2017-2018): two ½-day trainings followed by monthly meetings with one high school (n = 20 youth). Trainings provided information on tobacco use, consequences, industry tactics, evidence-based tobacco control, and advocacy skills. Results provided support for expansion to Phase II (2018-20119): A 1-day training followed by monthly information sharing implemented in three counties (N = 80). Youth were surveyed before and 6-months posttraining during both phases. Phase I: At posttraining, 85% of youth believed they could reduce the amount of tobacco use in their community versus 66% at baseline. More students tried at least once to convince school or government officials to be more concerned about tobacco use (77% vs. 47%). Phase II: More students supported tobacco policies at posttraining survey and realized policies are an effective strategy to reduce tobacco use. At posttraining survey, students reported greater interpersonal confidence talking with others about tobacco-related issues, with a 24% increase in confidence talking with adults in their communities, as well as greater advocacy self-efficacy. Youth in Appalachia demonstrate desire to influence tobacco use and policy to improve health equity. Findings reinforce the need for collaborative public health interventions to promote ongoing training and support for youth living in high-risk communities.

The Potential for Screening for Intimate Partner Violence in Community Pharmacies: An Exploratory Study of Female Consumers' Perspectives.

Intimate partner violence (IPV) is a substantial public health problem. The U.S. Preventive Services Task Force recently updated guidelines to recommend IPV screening for all women of childbearing age. Expansion of screening efforts to the community pharmacy setting could provide an opportunity to substantially impact the health of consumers. To date, no research has explored consumers' perspective on IPV screening in the community pharmacy environment. To address this gap, a descriptive survey research study was conducted to examine female consumers' attitudes and preferences for IPV screening in community pharmacies. Female pharmacy customers ( N = 60) completed an online survey assessing knowledge of and attitudes about community pharmacies as sources of health care advice, beliefs about IPV and IPV screening, and perspectives on IPV screening in the community pharmacy environment. Consumers who utilized pharmacies with more patient care services were more likely to report interest in IPV screening in the pharmacy environment. The majority of respondents thought IPV screening is an important thing to do (85.0%), and 33.3% agreed that it should happen in a pharmacy. A statistically significant relationship between the belief that the pharmacy is a good place for health education and preference for IPV screening in the community pharmacy environment was found, r(58) = .43, p < .001. Concern regarding the time required to conduct screenings and about the availability of appropriate space were identified as potential barriers to screening in the pharmacy environment.

Gemtuzumab Ozogamicin (GO) Inclusion to Induction Chemotherapy Eliminates Leukemic Initiating Cells and Significantly Improves Survival in Mouse Models of Acute Myeloid Leukemia.

Gemtuzumab ozogamicin (GO) is an anti-CD33 antibody-drug conjugate for the treatment of acute myeloid leukemia (AML). Although GO shows a narrow therapeutic window in early clinical studies, recent reports detailing a modified dosing regimen of GO can be safely combined with induction chemotherapy, and the combination provides significant survival benefits in AML patients. Here we tested whether the survival benefits seen with the combination arise from the enhanced reduction of chemoresidual disease and leukemic initiating cells (LICs). Herein, we use cell line and patient-derived xenograft (PDX) AML models to evaluate the combination of GO with daunorubicin and cytarabine (DA) induction chemotherapy on AML blast growth and animal survival. DA chemotherapy and GO as separate treatments reduced AML burden but left significant chemoresidual disease in multiple AML models. The combination of GO and DA chemotherapy eliminated nearly all AML burden and extended overall survival. In two small subsets of AML models, chemoresidual disease following DA chemotherapy displayed hallmark markers of leukemic LICs (CLL1 and CD34). In vivo, the two chemoresistant subpopulations (CLL1+/CD117- and CD34+/CD38+) showed higher ability to self-renewal than their counterpart subpopulations, respectively. CD33 was coexpressed in these functional LIC subpopulations. We demonstrate that the GO and DA induction chemotherapy combination more effectively eliminates LICs in AML PDX models than either single agent alone. These data suggest that the survival benefit seen by the combination of GO and induction chemotherapy, nonclinically and clinically, may be attributed to the enhanced reduction of LICs.

Discovery of 1-{(3R,4R)-3-[({5-Chloro-2-[(1-methyl-1H-pyrazol-4-yl)amino]-7H-pyrrolo[2,3-d]pyrimidin-4-yl}oxy)methyl]-4-methoxypyrrolidin-1-yl}prop-2-en-1-one (PF-06459988), a Potent, WT Sparing, Irreversible Inhibitor of T790M-Containing EGFR Mutants.

First generation EGFR TKIs (gefitinib, erlotinib) provide significant clinical benefit for NSCLC cancer patients with oncogenic EGFR mutations. Ultimately, these patients' disease progresses, often driven by a second-site mutation in the EGFR kinase domain (T790M). Another liability of the first generation drugs is severe adverse events driven by inhibition of WT EGFR. As such, our goal was to develop a highly potent irreversible inhibitor with the largest selectivity ratio between the drug-resistant double mutants (L858R/T790M, Del/T790M) and WT EGFR. A unique approach to develop covalent inhibitors, optimization of reversible binding affinity, served as a cornerstone of this effort. PF-06459988 was discovered as a novel, third generation irreversible inhibitor, which demonstrates (i) high potency and specificity to the T790M-containing double mutant EGFRs, (ii) minimal intrinsic chemical reactivity of the electrophilic warhead, (iii) greatly reduced proteome reactivity relative to earlier irreversible EGFR inhibitors, and (iv) minimal activity against WT EGFR.

GLI2 inhibition abrogates human leukemia stem cell dormancy.

BACKGROUND: Dormant leukemia stem cells (LSC) promote therapeutic resistance and leukemic progression as a result of unbridled activation of stem cell gene expression programs. Thus, we hypothesized that 1) deregulation of the hedgehog (Hh) stem cell self-renewal and cell cycle regulatory pathway would promote dormant human LSC generation and 2) that PF-04449913, a clinical antagonist of the GLI2 transcriptional activator, smoothened (SMO), would enhance dormant human LSC eradication. METHODS: To test these postulates, whole transcriptome RNA sequencing (RNA-seq), microarray, qRT-PCR, stromal co-culture, confocal fluorescence microscopic, nanoproteomic, serial transplantation and cell cycle analyses were performed on FACS purified normal, chronic phase (CP) chronic myeloid leukemia (CML), blast crisis (BC) phase CML progenitors with or without PF-04449913 treatment. RESULTS: Notably, RNA-seq analyses revealed that Hh pathway and cell cycle regulatory gene overexpression correlated with leukemic progression. While lentivirally enforced GLI2 expression enhanced leukemic progenitor dormancy in stromal co-cultures, this was not observed with a mutant GLI2 lacking a transactivation domain, suggesting that GLI2 expression prevented cell cycle transit. Selective SMO inhibition with PF-04449913 in humanized stromal co-cultures and LSC xenografts reduced downstream GLI2 protein and cell cycle regulatory gene expression. Moreover, SMO inhibition enhanced cell cycle transit and sensitized BC LSC to tyrosine kinase inhibition in vivo at doses that spare normal HSC. CONCLUSION: In summary, while GLI2, forms part of a core HH pathway transcriptional regulatory network that promotes human myeloid leukemic progression and dormant LSC generation, selective inhibition with PF-04449913 reduces the dormant LSC burden thereby providing a strong rationale for clinical trials predicated on SMO inhibition in combination with TKIs or chemotherapeutic agents with the ultimate aim of obviating leukemic therapeutic resistance, persistence and progression.

Contrast agents for quantitative microCT of lung tumors in mice.

The identification and quantitative evaluation of lung tumors in mouse models is challenging and an unmet need in preclinical arena. In this study, we developed a noninvasive contrast-enhanced microCT (µCT) method to longitudinally evaluate and quantitate lung tumors in mice. Commercially available µCT contrast agents were compared to determine the optimal agent for visualization of thoracic blood vessels and lung tumors in naïve mice and in non-small-cell lung cancer models. Compared with the saline control, iopamidol and iodinated lipid agents provided only marginal increases in contrast resolution. The inorganic nanoparticulate agent provided the best contrast and visualization of thoracic vascular structures; the density contrast was highest at 15 min after injection and was stable for more than 4 h. Differential contrast of the tumors, vascular structures, and thoracic air space by the nanoparticulate agent enabled identification of tumor margins and accurate quantification. µCT data correlated closely with traditional histologic measurements (Pearson correlation coefficient, 0.995). Treatment of ELM4-ALK mice with crizotinib yielded 65% reduction in tumor size and thus demonstrated the utility of quantitative µCT in longitudinal preclinical trials. Overall and among the 3 agents we tested, the inorganic nanoparticulate product was the best commercially available contrast agent for visualization of thoracic blood vessels and lung tumors. Contrast-enhanced µCT imaging is an excellent noninvasive method for longitudinal evaluation during preclinical lung tumor studies.

Antitumor Efficacy of the Dual PI3K/mTOR Inhibitor PF-04691502 in a Human Xenograft Tumor Model Derived from Colorectal Cancer Stem Cells Harboring a PIK3CA Mutation.

PIK3CA (phosphoinositide-3-kinase, catalytic, alpha polypeptide) mutations can help predict the antitumor activity of phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway inhibitors in both preclinical and clinical settings. In light of the recent discovery of tumor-initiating cancer stem cells (CSCs) in various tumor types, we developed an in vitro CSC model from xenograft tumors established in mice from a colorectal cancer patient tumor in which the CD133+/EpCAM+ population represented tumor-initiating cells. CD133+/EpCAM+ CSCs were enriched under stem cell culture conditions and formed 3-dimensional tumor spheroids. Tumor spheroid cells exhibited CSC properties, including the capability for differentiation and self-renewal, higher tumorigenic potential and chemo-resistance. Genetic analysis using an OncoCarta™ panel revealed a PIK3CA (H1047R) mutation in these cells. Using a dual PI3K/mTOR inhibitor, PF-04691502, we then showed that blockage of the PI3K/mTOR pathway inhibited the in vitro proliferation of CSCs and in vivo xenograft tumor growth with manageable toxicity. Tumor growth inhibition in mice was accompanied by a significant reduction of phosphorylated Akt (pAKT) (S473), a well-established surrogate biomarker of PI3K/mTOR signaling pathway inhibition. Collectively, our data suggest that PF-04691502 exhibits potent anticancer activity in colorectal cancer by targeting both PIK3CA (H1047R) mutant CSCs and their derivatives. These results may assist in the clinical development of PF-04691502 for the treatment of a subpopulation of colorectal cancer patients with poor outcomes.

Evaluation and initial in vitro and ex vivo characterization of the potential positron emission tomography ligand, BU99008 (2-(4,5-dihydro-1H-imidazol-2-yl)-1- methyl-1H-indole), for the imidazoline2 binding site.

The density of the Imidazoline2 binding site (I2BS) has been shown to change in psychiatric conditions such as depression and addiction, along with neurodegenerative disorders such as Alzheimer's disease and Huntington's chorea. The presence of I2BS on glial cells and the possibility that they may in some way regulate glial fibrillary acidic protein has led to increased interest into the role of I2BS and I2BS ligands in conditions characterized by marked gliosis. In addition, it has been suggested that I2BS may be a marker for human glioblastomas. Therefore, the development of a positron emission tomography (PET) radioligand for the I2BS would be of major benefit in our understanding of these conditions. We now report the successful synthesis and initial pharmacological evaluation of potential PET radioligands for the I2BS as well as the tritiation and characterization of the most favorable of the series, BU99008 (6), both in vitro and ex vivo in rat. The series as a whole demonstrated excellent affinity and selectivity for the I2BS, with BU99008 (6) selected as the lead candidate to be taken forward for in vivo assessment. BU99008 (6) showed very good affinity for the I2BS (K(i) of 1.4 nM; K(d) = 1.3 nM), good selectivity compared with the α2 -adrenoceptor (909-fold). In addition, following peripheral administration, [³H]BU99008 demonstrated a heterogenous uptake into the rat brain consistent with the known distribution of the I2BS in vivo. This, and the amenability of BU99008 (6) to radiolabeling with a positron-emitting radioisotope, indicates its potential as a PET radioligand for imaging the I2BS in vivo.

ErbB3 is required for ductal morphogenesis in the mouse mammary gland.

INTRODUCTION: The receptor ErbB3/HER3 is often over-expressed in human breast cancers, frequently in conjunction with over-expression of the proto-oncogene ERBB2/HER2/NEU. Although the prognostic/predictive value of ErbB3 expression in breast cancer is unclear, ErbB3 is known to contribute to therapeutic resistance. Understanding ErbB3 functions in the normal mammary gland will help to explain its role in cancer etiology and as a modulator of signaling responses to the mammary oncogene ERBB2. METHODS: To investigate the roles of ErbB3 in mouse mammary gland development, we transplanted mammary buds from ErbB3-/- embryos into the cleared mammary fat pads of wild-type immunocompromised mice. Effects on ductal outgrowth were analyzed at 4 weeks, 7 weeks and 20 weeks after transplantation for total ductal outgrowth, branch density, and number and area of terminal end buds. Sections of glands containing terminal end buds were analyzed for number and epithelial area of terminal end buds. Terminal end buds were also analyzed for presence of mitotic figures, apoptotic figures, BrdU incorporation, and expression of E-cadherin, P-cadherin, alpha-smooth muscle actin, and cleaved caspase-3. RESULTS: The mammary ductal trees developed from ErbB3-/- buds only partly filled the mammary fat pad. In contrast to similar experiments with ErbB2-/- mammary buds, this phenotype was maintained through adulthood, pregnancy, and parturition. In addition, and in contrast to similar work with ErbB4-/- mammary buds, lobuloalveolar development of ErbB3-/- transplanted glands was normal. The ErbB3-/- mammary outgrowth defect was associated with a decrease in the size of the terminal end buds, and with increases in branch density, in the number of terminal end buds, and in the number of luminal spaces. Proliferation rates were not affected by the lack of ErbB3, but there was an increase in apoptosis in ErbB3-/- terminal end buds. CONCLUSIONS: Endogenous ErbB3 regulates morphogenesis of mammary epithelium.

ErbB2 is required for ductal morphogenesis of the mammary gland.

The ERBB2/HER2/NEU receptor tyrosine kinase gene is amplified in up to 30% of human breast cancers. The frequent and specific selection of this receptor kinase gene for amplification in breast cancer implies that it has important normal functions in the mammary gland. To investigate the functions of ErbB2 during normal mouse mammary gland development, we transplanted mammary buds from genetically rescued ErbB2(-/-) embryos that express ErbB2 in the cardiac muscle. ErbB2(-/-) mammary buds transplanted to a wild-type mammary fat pad support outgrowth of an epithelial tree that advances only slowly through the mammary fat pad at puberty. This penetration defect is associated with structural defects in terminal end buds, characterized by a decrease in body cell number, an increased presence of cap-like cells in the prelumenal compartment, and the presence of large luminal spaces. Lobuloalveolar development was not affected in glands that developed from ErbB2(-/-) transplanted tissue. The results may have implications for the aggressive phenotypes associated with ERBB2-overexpressing mammary carcinomas.

Increased neurogenesis and brain-derived neurotrophic factor in neurokinin-1 receptor gene knockout mice.

It has previously been shown that chronic treatment with antidepressant drugs increases neurogenesis and levels of brain-derived neurotrophic factor in the hippocampus. These changes have been correlated with changes in learning and long-term potentiation and may contribute to the therapeutic efficacy of antidepressant drug treatment. Recently, antagonists at the neurokinin-1 receptor, the preferred receptor for the neuropeptide substance P, have been shown to have antidepressant activity. Mice with disruption of the neurokinin-1 receptor gene are remarkably similar both behaviourally and neurochemically to mice maintained chronically on antidepressant drugs. We demonstrate here that there is a significant elevation of neurogenesis but not cell survival in the hippocampus of neurokinin-1 receptor knockout mice. Neurogenesis can be increased in wild-type but not neurokinin-1 receptor knockout mice by chronic treatment with antidepressant drugs which preferentially target noradrenergic and serotonergic pathways. Hippocampal levels of brain-derived neurotrophic factor are also two-fold higher in neurokinin-1 receptor knockout mice, whereas cortical levels are similar. Finally, we examined hippocampus-dependent learning and memory but found no clear enhancement in neurokinin-1 receptor knockout mice. These data argue against a simple correlation between increased levels of neurogenesis or brain-derived neurotrophic factor and mnemonic processes in the absence of increased cell survival. They support the hypothesis that increased neurogenesis, perhaps accompanied by higher levels of brain-derived neurotrophic factor, may contribute to the efficacy of antidepressant drug therapy.

Drosophila screening model for metastasis: Semaphorin 5c is required for l(2)gl cancer phenotype.

Cancer metastasis is a complex process involving many genes and pathways. This complexity hinders the identification of molecules functionally required for this process. We have developed and used a Drosophila screening system to identify genes that are functionally important for tumorigenicity and metastasis. Deletion of Drosophila lethal giant larvae (l(2)gl) leads to highly invasive and widely metastatic tumors on transplantation into adult flies. Random homozygous P element insertions were screened for the ability to modulate the l(2)gl phenotype. Analysis of metastasis patterns of the lines containing P element insertions and lacking wild-type l(2)gl expression identified three homozygous mutations that dramatically alter tumorigenesis and/or metastasis. Semaphorin 5c (Sema 5c) is required for tumorigenicity, apontic overexpression suppresses metastasis but not tumorigenicity, and pointed up-regulation accelerates lethality of l(2)gl tumors. Furthermore, class 5 semaphorins are shown to be expressed in cancer cells and localized to the membrane. Drosophila Sema-5c and the mammalian homologs are transmembrane proteins with extracellular thrombospondin type I (TspI) repeats. TspI repeats are known in some proteins to bind and activate transforming growth factor (TGF)-beta ligand. Phospho-Mad and the downstream target gene vestigial were elevated in l(2)gl tumors, thus linking Drosophila neoplasia to the Dpp (TGF-beta-like) signal pathway. The activation of the Dpp pathway in l(2)gl tumors occurred only in the presence of Sema-5c. This study demonstrates that the power of Drosophila genetics can be applied to screen, identify, and characterize molecules that are functionally required for invasion and metastasis.

Neural and mammary gland defects in ErbB4 knockout mice genetically rescued from embryonic lethality.

Mice lacking the epidermal growth factor receptor family member ErbB4 exhibit defects in cranial neural crest cell migration but die by embryonic day 11 because of defective heart development. To examine later phenotypes, we rescued the heart defects in ErbB4 mutant mice by expressing ErbB4 under a cardiac-specific myosin promoter. Rescued ErbB4 mutant mice reach adulthood and are fertile. However, during pregnancy, mammary lobuloalveoli fail to differentiate correctly and lactation is defective. Rescued mice also display aberrant cranial nerve architecture and increased numbers of large interneurons within the cerebellum.