SMARCB1 regulates the hypoxic stress response in sickle cell trait

Renal medullary carcinoma (RMC) is an aggressive kidney cancer that almost exclusively develops in individuals with sickle cell trait (SCT) and is always characterized by loss of the tumor suppressor SMARCB1. Because renal ischemia induced by red blood cell sickling exacerbates chronic renal medullary hypoxia in vivo, we investigated whether the loss of SMARCB1 confers a survival advantage under the setting of SCT. Hypoxic stress, which naturally occurs within the renal medulla, is elevated under the setting of SCT. Our findings showed that hypoxia-induced SMARCB1 degradation protected renal cells from hypoxic stress. SMARCB1 wild-type renal tumors exhibited lower levels of SMARCB1 and more aggressive growth in mice harboring the SCT mutation in human hemoglobin A (HbA) than in control mice harboring wild-type human HbA. Consistent with established clinical observations, SMARCB1-null renal tumors were refractory to hypoxia-inducing therapeutic inhibition of angiogenesis. Further, reconstitution of SMARCB1 restored renal tumor sensitivity to hypoxic stress in vitro and in vivo. Together, our results demonstrate a physiological role for SMARCB1 degradation in response to hypoxic stress, connect the renal medullary hypoxia induced by SCT with an increased risk of SMARCB1-negative RMC, and shed light into the mechanisms mediating the resistance of SMARCB1-null renal tumors against angiogenesis inhibition therapies.

PRMT1-dependent regulation of RNA metabolism and DNA damage response sustains pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that has remained clinically challenging to manage. Here we employ an RNAi-based in vivo functional genomics platform to determine epigenetic vulnerabilities across a panel of patient-derived PDAC models. Through this, we identify protein arginine methyltransferase 1 (PRMT1) as a critical dependency required for PDAC maintenance. Genetic and pharmacological studies validate the role of PRMT1 in maintaining PDAC growth. Mechanistically, using proteomic and transcriptomic analyses, we demonstrate that global inhibition of asymmetric arginine methylation impairs RNA metabolism, which includes RNA splicing, alternative polyadenylation, and transcription termination. This triggers a robust downregulation of multiple pathways involved in the DNA damage response, thereby promoting genomic instability and inhibiting tumor growth. Taken together, our data support PRMT1 as a compelling target in PDAC and informs a mechanism-based translational strategy for future therapeutic development.Statement of significancePDAC is a highly lethal cancer with limited therapeutic options. This study identified and characterized PRMT1-dependent regulation of RNA metabolism and coordination of key cellular processes required for PDAC tumor growth, defining a mechanism-based translational hypothesis for PRMT1 inhibitors.

Targeting CDK4 overcomes EMT-mediated tumor heterogeneity and therapeutic resistance in KRAS mutant lung cancer

Lack of sustained response to therapeutic agents in patients with KRAS-mutant lung cancer poses a major challenge and arises partly due to intratumor heterogeneity that defines phenotypically distinct tumor subpopulations. To attain better therapeutic outcomes, it is important to understand the differential therapeutic sensitivities of tumor cell subsets. Epithelial-mesenchymal transition is a biological phenomenon that can alter the state of cells along a phenotypic spectrum and cause transcriptional rewiring to produce distinct tumor cell subpopulations. We utilized functional shRNA screens, in in vitro and in vivo models, to identify and validate an increased dependence of mesenchymal tumor cells on cyclin-dependent kinase 4 (CDK4) for survival, as well as a mechanism of resistance to MEK inhibitors. High zinc finger E-box binding homeobox 1 levels in mesenchymal tumor cells repressed p21, leading to perturbed CDK4 pathway activity. Increased dependence on CDK4 rendered mesenchymal cancer cells particularly vulnerable to selective CDK4 inhibitors. Coadministration of CDK4 and MEK inhibitors in heterogeneous tumors effectively targeted different tumor subpopulations, subverting the resistance to either single-agent treatment.

Sequential Administration of XPO1 and ATR Inhibitors Enhances Therapeutic Response in TP53-mutated Colorectal Cancer

BACKGROUND & AIMS

Understanding the mechanisms by which tumors adapt to therapy is critical for developing effective combination therapeutic approaches to improve clinical outcomes for patients with cancer.

METHODS

To identify promising and clinically actionable targets for managing colorectal cancer (CRC), we conducted a patient-centered functional genomics platform that includes approximately 200 genes and paired this with a high-throughput drug screen that includes 262 compounds in four patient-derived xenografts (PDXs) from patients with CRC.

RESULTS

Both screening methods identified exportin 1 (XPO1) inhibitors as drivers of DNA damage-induced lethality in CRC. Molecular characterization of the cellular response to XPO1 inhibition uncovered an adaptive mechanism that limited the duration of response in TP53-mutated, but not in TP53-wild-type CRC models. Comprehensive proteomic and transcriptomic characterization revealed that the ATM/ATR-CHK1/2 axes were selectively engaged in TP53-mutant CRC cells upon XPO1 inhibitor treatment and that this response was required for adapting to therapy and escaping cell death. Administration of KPT-8602, an XPO1 inhibitor, followed by AZD-6738, an ATR inhibitor, resulted in dramatic antitumor effects and prolonged survival in TP53-mutant models of CRC.

CONCLUSIONS

Our findings anticipate tremendous therapeutic benefit and support the further evaluation of XPO1 inhibitors, especially in combination with DNA damage checkpoint inhibitors, to elicit an enduring clinical response in patients with CRC harboring TP53 mutations.

ZEB1 suppression sensitizes KRAS mutant cancers to MEK inhibition by an IL17RD-dependent mechanism

Mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitors have failed to show clinical benefit in Kirsten rat sarcoma (KRAS) mutant lung cancer due to various resistance mechanisms. To identify differential therapeutic sensitivities between epithelial and mesenchymal lung tumors, we performed in vivo small hairpin RNA screens, proteomic profiling, and analysis of patient tumor datasets, which revealed an inverse correlation between mitogen-activated protein kinase (MAPK) signaling dependency and a zinc finger E-box binding homeobox 1 (ZEB1)-regulated epithelial-to-mesenchymal transition. Mechanistic studies determined that MAPK signaling dependency in epithelial lung cancer cells is due to the scaffold protein interleukin-17 receptor D (IL17RD), which is directly repressed by ZEB1. Lung tumors in multiple Kras mutant murine models with increased ZEB1 displayed low IL17RD expression, accompanied by MAPK-independent tumor growth and therapeutic resistance to MEK inhibition. Suppression of ZEB1 function with miR-200 expression or the histone deacetylase inhibitor mocetinostat sensitized resistant cancer cells to MEK inhibition and markedly reduced in vivo tumor growth, showing a promising combinatorial treatment strategy for KRAS mutant cancers. In human lung tumor samples, high ZEB1 and low IL17RD expression correlated with low MAPK signaling, presenting potential markers that predict patient response to MEK inhibitors.

Abstract B104: Combined inhibition of DDR1 and CDK4/6 induces synergistic effects in ER-positive, HER2-negative breast cancer with PIK3CA/AKT1 mutations

Molecular alterations in the PI3K/AKT/mTOR pathway occur frequently in estrogen receptor-positive (ER-positive) breast tumors. Patients with ER-positive, human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer (MBC) are often treated with palbociclib, an FDA approved CDK4/6 inhibitor, in combination with endocrine therapy. In clinical studies (NCT01942135), the combination of fulvestrant plus palbociclib was associated with improved progression-free survival compared with fulvestrant plus placebo, irrespective of PIK3CA mutational status. The purpose of this study is to identify synthetic lethality partner that can be targeted in combination with palbociclib to improve its therapeutic response. We demonstrate that the in vitro efficacy of CDK4/6 inhibitor is reduced in the presence of PIK3CA/AKT1 mutations using ER-positive isogenic breast cancer cell lines. Utilizing a shRNA library screen targeting cancer related human kinases, we identified that genomic suppression of discoidin domain receptor 1 (DDR1), a tyrosine kinase active in various cancers, is synthetic lethal with palbociclib. Performing sulforhodamine B (SRB) proliferation assay, DDR1 knockdown by shRNA significantly reduced growth of PIK3CA/AKT1 mutant as well as wild type ER-positive cell lines. In addition, DDR1 pharmacological inhibitor, 7rh benzamide, activated the P53/P21 pathway and enhanced the sensitivity of PIK3CA/AKT1 mutant cells to palbociclib. Likewise, we found that combined treatment of palbociclib and 7rh further induced cell cycle arrest through decreasing G2-M phase population and reducing FoxM1 and Rb phosphorylation in mutant cell lines. Our data indicate that DDR1 inhibition can augment cell cycle suppressive effect of palbociclib and could be an effective rational strategy approach for targeted therapy of ER-positive, HER2-negative breast cancer harboring PIK3CA/AKT1 mutations.

Citation Format: Maryam Shariati, Christopher A Bristow, Alessandro Carugo, Tim Heffernan, Xiaofeng Zheng, Michael D Peoples, Debu Tripathy, Funda Meric-Bernstam. Combined inhibition of DDR1 and CDK4/6 induces synergistic effects in ER-positive, HER2-negative breast cancer with PIK3CA/AKT1 mutations [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 B104. doi:10.1158/1535-7163.TARG-19-B104

Abstract C036: Discovery of IACS-13909, an allosteric SHP2 inhibitor that overcomes multiple mechanisms underlying osimertinib resistance

Osimertinib, a third generation EGFR inhibitor, is a front-line therapy for EGFR mutated non-small lung cancer (NSCLC). The long-term effectiveness of osimertinib is limited by acquired resistance. Clinically identified resistance mechanisms include EGFR-dependent mechanisms such as mutations on EGFR that preclude drug binding, and EGFR-independent activation of the MAPK pathway, for instance via activation of alternate RTKs. It has also been noted that frequently a tumor from a single patient harbors more than one resistance mechanism, and the plasticity between the multiple resistance mechanisms will restrict the effectiveness of therapies targeting a single node of the oncogenic signaling network. SHP2 (Src homology 2 domain-containing phosphatase) is a phosphatase that mediates the signaling of multiple RTKs and is required for full activation of the MAPK pathway. Here we report IACS-13909 - a specific and potent allosteric inhibitor of SHP2 - suppresses the signaling of RTK/MAPK pathway. IACS-13909 potently impedes the proliferation of tumors with a broad spectrum of RTKs as the oncogenic driver. Importantly, in NSCLC models with acquired resistance to osimertinib, IACS-13909 administered as a single agent or in combination with osimertinib potently reduces tumor cell proliferation in vitro and in vivo. Together, our findings provide preclinical evidence for using a SHP2 inhibitor as a therapeutic strategy in acquired EGFR inhibitor-resistant NSCLC. Currently, a compound that potently inhibits SHP2 has been selected as the clinical development candidate and is undergoing IND-enabling studies with a projected first-in-human target of early 2020.

Citation Format: Yuting Sun, Brooke A Meyers, Sarah B Johnson, Angela L Harris, Barbara Czako, Jason B Cross, Paul G Leonard, Faika Mseeh, Maria E Di Francesco, Connor A Parker, Qi Wu, Christopher A Bristow, Jason P Burke, Caroline C Carrillo, Christopher L Carroll, Qing Chang, Ningping Feng, Sonal Gera, Gao Guang, Justin Kwang-Lay Huang, Yongying Jiang, Zhijun Kang, Jeffrey J Kovacs, Xiaoyan Ma, Pijus K Mandal, Timothy McAfoos, Robert A Mullinax, Michael D Peoples, Vandhana Ramamoorthy, Sahil Seth, Erika Suzuki, Christopher Conrad Williams, Simon S Yu, Andy M Zuniga, Giulio F Draetta, Joseph R Marszalek, Timothy P Heffernan, Nancy E Kohl, Philip Jones. Discovery of IACS-13909, an allosteric SHP2 inhibitor that overcomes multiple mechanisms underlying osimertinib resistance [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 C036. doi:10.1158/1535-7163.TARG-19-C036

ZEB1/NuRD complex suppresses TBC1D2b to stimulate E-cadherin internalization and promote metastasis in lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, due in part to the propensity of lung cancer to metastasize. Aberrant epithelial-to-mesenchymal transition (EMT) is a proposed model for the initiation of metastasis. During EMT cell-cell adhesion is reduced allowing cells to dissociate and invade. Of the EMT-associated transcription factors, ZEB1 uniquely promotes NSCLC disease progression. Here we apply two independent screens, BioID and an Epigenome shRNA dropout screen, to define ZEB1 interactors that are critical to metastatic NSCLC. We identify the NuRD complex as a ZEB1 co-repressor and the Rab22 GTPase-activating protein TBC1D2b as a ZEB1/NuRD complex target. We find that TBC1D2b suppresses E-cadherin internalization, thus hindering cancer cell invasion and metastasis.

Non-small cell lung cancer (NSCLC) is often associated with metastasis to the lungs. Here, the authors perform independent screens and identify NuRD as a co-repressor of ZEB1, and demonstrate TBC1D2b as a downstream target of ZEB1/NuRD complex regulating NSCLC metastasis.

Abstract 317: Vecabrutinib inhibits C481 mutated Bruton's tyrosine kinase and its downstream signaling in vitro

Inhibition of Bruton’s Tyrosine Kinase (BTK) by ibrutinib, an irreversible inhibitor, has dramatically improved the outcomes in both previously treated and naïve chronic lymphocytic leukemia (CLL) patients. Ibrutinib inactivates BTK through covalently binding to the cysteine 481 residue (C481) which then leads to the inhibition of autophosphorylation of BTK and the inactivation of downstream survival nexus. Although ibrutinib demonstrated >90% overall and event-free survival, about 25% of patients discontinue ibrutinib due to leukemia progression and intolerance. Patients that initially respond to treatment may develop resistance and the most prevalent resistance mechanism of ibrutinib is described as the point mutation affecting the C481 residue of BTK that results in disruption of ibrutinib binding and acquired ibrutinib resistance. Most common mutations are C481S and C481R. Vecabrutinib is a potent reversible BTK inhibitor that binds to BTK through noncovalent interactions. As vecabrutinib does not require binding to C481 residue, it retains its efficacy with mutant BTK in vitro. To better understand differential biology of Wild-Type (WT) and serine and arginine substituted BTK, we labelled MEC-1 cell line with green fluorescence protein (GFP) and overexpressed either BTKWT, BTKC481Sor BTKC481R that contributes to ibrutinib resistance. We selected MEC-1 cell line as it represents CLL disease and the phenotype of the cells share several characteristics of ex vivo CLL cells. We performed Reverse Phase Protein Array (RPPA) and mRNA-sequencing to determine and compare the proteomic and transcriptomic profiles of the MEC-1 cells harboring WT and mutant BTK. Ingenuity Pathway Analysis (IPA) of RPPA data revealed that overexpression of BTK WT leads to the enrichment of protein alterations involved in cell cycle regulation, B cell receptor signaling, PI3K/AKT signaling, PTEN signaling and ERK/MAPK signaling. IPA of RNAseq data upon BTK WT overexpression unraveled the top canonical pathways that include signaling through axonal guidance, ephrin receptor, c-AMP mediated, CXCR4 signaling and PTEN signaling. Comparative analysis of MEC-1 cells with mutant BTK (C481S vs C481R) using IPA distinguished the activated pathways in BTKC481Sharboring cells from cells that express BTKC481R. These results are being validated by western blot and qRT-PCR assays. Immunoblotting results showed that following 24, 48, and 72 hour of vecabrutinib (at 1 µM) treatment reduced p-BTK (Tyr223), p-PLCG2 (Tyr759) and p-ERK (Thr 202/Tyr 204) levels in MEC-1 cells with mutant BTK. These data indicate that vecabrutinib effectively inhibits BTK and its downstream signaling in the presence of mutant BTK, suggesting that vecabrutinib treatment may be a rational approach to overcome ibrutinib resistance.

Citation Format: Burcu Aslan, Mikhila Mahendra, Michael D Peoples, Joe R. Marszalek, Christopher P Vellano, Xiaofeng Zheng, Jing Wang, Pietro Taverna, Varsha Gandhi. Vecabrutinib inhibits C481 mutated Bruton's tyrosine kinase and its downstream signaling in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 317.

Ntrk1 Promotes Resistance to PD-1 Checkpoint Blockade in Mesenchymal Kras/p53 Mutant Lung Cancer

The implementation of cancer immunotherapeutics for solid tumors including lung cancers has improved clinical outcomes in a small percentage of patients. However, the majority of patients show little to no response or acquire resistance during treatment with checkpoint inhibitors delivered as a monotherapy. Therefore, identifying resistance mechanisms and novel combination therapy approaches is imperative to improve responses to immune checkpoint inhibitors. To address this, we performed an in vivo shRNA dropout screen that focused on genes encoding for FDA-approved drug targets (FDAome). We implanted epithelial and mesenchymal Kras/p53 (KP) mutant murine lung cancer cells expressing the FDAome shRNA library into syngeneic mice treated with an anti-PD-1 antibody. Sequencing for the barcoded shRNAs revealed Ntrk1 was significantly depleted from mesenchymal tumors challenged with PD-1 blockade, suggesting it provides a survival advantage to tumor cells when under immune system pressure. Our data confirmed Ntrk1 transcript levels are upregulated in tumors treated with PD-1 inhibitors. Additionally, analysis of tumor-infiltrating T cell populations revealed that Ntrk1 can promote CD8+ T cell exhaustion. Lastly, we found that Ntrk1 regulates Jak/Stat signaling to promote expression of PD-L1 on tumor cells. Together, these data suggest that Ntrk1 activates Jak/Stat signaling to regulate expression of immunosuppressive molecules including PD-L1, promoting exhaustion within the tumor microenvironment.

Abstract P6-18-13: Identification of optimal combination therapy partners for PI3K/Akt/mTOR pathway inhibitor in triple negative breast cancer

Triple-negative breast cancer (TNBC) is among the most aggressive subtypes, accounts for 10-15% of all breast cancer cases and is characterized by a lack of hormone receptors with a low overall survival rate. Due to the heterogeneity nature of this disease, the absence of validated molecular targets makes it unresponsive to conventional therapies. PI3K/Akt/mTOR pathway is aberrantly activated in TNBC, but single agent therapy is commonly subject to resistance. The goal of this study is to identify the genes that can be targeted to enhance the efficacy of mTOR inhibitor TAK228, an agent that is being investigated as a treatment for advanced solid tumors, in TNBC with PI3K pathway activation. We utilized an in vivo pooled barcoded shRNA library screening to determine the genes that have the potential to be used as TAK228 synthetic lethal partners. Using deep sequencing analysis of the shRNA profiles, we identified several genes whose loss of function conferred synthetic lethality in the presence of TAK228. We found that targeting the candidate genes (WEE1, BMX and MAPK15) with their inhibitors (AZD1775, Ibrutinib and Sunitinib) did not significantly affect the viability, however combination treatment of these agents with TAK228 induced a robust growth inhibition and demonstrated a significant synergy in MDA-MB-468 cell lines. Investigating the activation of relevant survival signaling pathways will further elucidate the mechanism of synthetic lethal interaction. These observations provide a promising rational strategy for the treatment of TNBC with PI3K pathway aberration.

Citation Format: Shariati M, Paez-Arango N, Bristow CA, Evans KW, Peoples MD, Carugo A, Heffernan TP, Meric-Bernstam F. Identification of optimal combination therapy partners for PI3K/Akt/mTOR pathway inhibitor in triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-13.

Increased Tumor Glycolysis Characterizes Immune Resistance to Adoptive T Cell Therapy

Adoptive T cell therapy (ACT) produces durable responses in some cancer patients; however, most tumors are refractory to ACT and the molecular mechanisms underlying resistance are unclear. Using two independent approaches, we identified tumor glycolysis as a pathway associated with immune resistance in melanoma. Glycolysis-related genes were upregulated in melanoma and lung cancer patient samples poorly infiltrated by T cells. Overexpression of glycolysis-related molecules impaired T cell killing of tumor cells, whereas inhibition of glycolysis enhanced T cell-mediated antitumor immunity in vitro and in vivo. Moreover, glycolysis-related gene expression was higher in melanoma tissues from ACT-refractory patients, and tumor cells derived from these patients exhibited higher glycolytic activity. We identified reduced levels of IRF1 and CXCL10 immunostimulatory molecules in highly glycolytic melanoma cells. Our findings demonstrate that tumor glycolysis is associated with the efficacy of ACT and identify the glycolysis pathway as a candidate target for combinatorial therapeutic intervention.

Abstract IA12: An in vivo high throughput shRNA screening platform for identifying ways to target genomic alterations

Comprehensive characterization of genomic alterations prevalent in head and neck squamous cell carcinoma (HNSCC) has been performed by our group and others, and more recently by The Cancer Genome Atlas (TCGA) project. A significant barrier towards targeting the genomic alterations collectively found in HNSCC is that the genomic landscape of this disease is dominated by mutations to tumor suppressor genes that are inherently difficult to target, with very few mutated oncogenes present. Although potentially targetable oncogenic drivers may exist within chromosomal regions of copy number gain, the large number of genes within these regions makes identifying the precise targets challenging. To overcome some of these difficulties, we have been leveraging high throughput loss of function shRNA screens performed in vivo in order to identify co-dependencies and potential ways to target genomic alterations in HNSCC. Using a large panel of genomically characterized established HNSCC cell lines in conjunction with several different shRNA libraries, including ones that target druggable genes (i.e. FDAome), genes involved in DNA repair, and candidate HNSCC driver genes, we hope to link shRNA targets that are vital for in vivo growth and survival to specific genomic subtypes present within HNSCC. Following pooled in vitro infection with these libraries, HNSCC cell lines are injected into the flanks of mice where in vivo selection takes place, and dropout of barcoded shRNAs targeting genes advantageous for tumor growth is subsequently analyzed from harvested tumors by next generation sequencing. The FDAome library contains shRNAs to nearly 200 genes immediately targetable by FDA approved drugs, allowing identification of druggable co-dependent pathways through simple lethality. By comparing dropout of shRNAs from tumors of mice treated with or without carboplatin, genes that chemosensitize tumors in vivo are also being identified within the FDAome and DNA repair shRNA libraries. Screens performed with our custom HNSCC shRNAs library targeting many genes from regions recurrently amplified in large subsets of patient tumors should identify which genes within these regions are true drivers and potentially interesting drug candidates. Thus far, we have completed in vivo screens employing the FDAome and DNA damage libraries on four different HNSCC cell lines, comprised of 3 different NOTCH1 mutants and one NOTCH1 wild type cell line, which collectively include two HPV-positive and two HPV-negative cell lines. Data analysis has identified a number of druggable targets that inhibit the growth of NOTCH1 mutant cell lines or that seem to be specific for HPV+ tumors. Some of these targets have been further validated through in vivo experiments employing single shRNAs to genes of interest, employing targeting sequences distinct from the libraries. The growth inhibitory effects for some of the hits are apparent in vivo, but not in vitro, highlighting the ability of this unique platform to identify genes or pathways that drive the three-dimensional growth of tumors in the microenvironment of the host. We have also completed an in vivo screen on two of the cell lines using the custom shRNA library that targets genes recurrently amplified in HNSCC, and are currently analyzing data. Preliminary analysis indicates that this high throughput in vivo shRNA screening platform is a promising and relevant approach for identifying co-dependencies and ways to target genomic alterations in cancer.

Citation Format: Tongxin Xie, Ramya L. Parimi, Manish F. Kumar, Liang P. Yang, Jiping Wang, Sahil Seth, Carugo Alessandro, Christopher A. Bristow, Frederick Scott Robinson, Michael D. Peoples, Heath Skinner, Jeffrey N. Myers, Curtis R. Pickering, Mitchell J. Frederick. An in vivo high throughput shRNA screening platform for identifying ways to target genomic alterations [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr IA12.

Production of transgenic calves expressing an shRNA targeting myostatin

Myostatin (MSTN) is a well-known negative regulator of muscle growth. Animals that possess mutations within this gene display an enhanced muscling phenotype, a desirable agricultural trait. Increased neonatal morbidity is common, however, resulting from complications arising from the birth of offspring with increased fetal muscle mass. The objective of the current research was to generate an attenuated MSTN-null phenotype in a large-animal model using RNA interference to enhance muscle development without the detrimental consequences of an inactivating mutation. To this end, we identified a series of short interfering RNAs that demonstrated effective suppression of MSTN mRNA and protein levels. To produce transgenic offspring capable of stable MSTN suppression in vivo, a recombinant lentiviral vector expressing a short hairpin RNA (shRNA) targeting MSTN for silencing was introduced into bovine fetal fibroblasts. These cells were used as nucleus donors for somatic cell nuclear transfer (SCNT). Twenty blastocysts were transferred into seven recipient cows resulting in five pregnancies. One transgenic calf developed to term, but died following delivery by Caesarean-section. As an alternative strategy, microinjection of recombinant lentiviral particles into the perivitelline space of in vitro-produced bovine zygotes was utilized to produce 40 transgenic blastocysts that were transferred into 14 recipient cows, resulting in 7 pregnancies. Five transgenic calves were produced, of which three expressed the transgene. This is the first report of transgenic livestock produced by direct injection of a recombinant lentivirus, and expressing transgenes encoding shRNAs targeting an endogenous gene (myostatin) for silencing.

Evaluation of the effects of the North Carolina Improved Pregnancy Outcome Project: implications for state-level decision-making

This study was designed to assess the effects of the North Carolina Improved Pregnancy Outcome (IPO) Project on use of prenatal care and incidence of low birthweight among its primarily Black registrants . Weighted least squares and stratified analysis procedures were used to scrutinize vital statistics data for subpopulation effects. IPO services were received by 51.7 per cent of Black women in the counties served by the project. For all Black registrants , the risk of receiving less than adequate prenatal care was 55.1 per cent of that of the comparison group. For Black teenage registrants , the risk was even less: 37.2 per cent of that of the comparison group. Nevertheless, no corresponding effects on the incidence of low birthweight could be detected. The evaluation methods used in this study can be applied to programs for mothers and infants in other locales to generate useful and practical information for state-level decision-making.

Measuring the impact of programs for mothers and infants on prenatal care and low birth weight: the value of refined analyses

During the past two decades, intervention strategies designed to improve the health status of mothers and infants have been widely disseminated, yet relatively few have been evaluated for effectiveness. Moreover, most reported investigations have involved straightforward comparisons of aggregate data, employing various degrees of methodological control. In this study, vital statistics data were used to assess the effects of the North Carolina Maternity and Infant Care (MIC) Project on use of prenatal care and low birth weight. A weighted least squares procedure was used to control for selected maternal characteristics and identify significant interactions. Analyses of total population data indicated only minor MIC effects. However, more careful scrutiny of subpopulation data suggests that MIC impacts differed across categories of maternal risk status, with the greatest influence observed among mothers and infants at greatest risk. These findings raise several questions regarding the genesis of differential effects and suggest areas of special concern in conducting, interpreting, and using evaluations of programs for mothers and infants.

Monitoring and assessment in maternal and child health: recommendations for action at the state level

Recent administration-sponsored changes in federal health policy and funding may harbor adverse effects for the health of mothers and children, and for the capabilities of state-level programs to serve them appropriately. Careful monitoring is required to assess the nature, extent, and impact of those changes. This paper examines several monitoring efforts in maternal and child health and recommends additional action at the state level to meet urgent information requirements.

A model for the delivery of health care to pregnant adolescents. Part I: assessment and planning

The development and implementation of a health care delivery system for pregnant adolescents is described. The setting was an already functioning urban obstetrical outpatient facility for maternal and infant care. The successes and failures that were experienced are shared with the reader. In Part I the specifics involved in planning and putting into operation an adolescent clinic session are enumerated. In Part II the actual implementation, evaluation, and replanning are discussed. Both parts are based on the nursing process and the manner in which it was utilized in planning and development.