Intentions to Use Cannabis Postpartum: A Qualitative Study of Pregnant Individuals Who Used Cannabis During Early Pregnancy.

Objective: To examine plans for postpartum cannabis use among pregnant individuals who used cannabis during early pregnancy. Materials and Methods: Eighteen virtual focus groups were conducted from November 17, 2021, to December 17, 2021, with 23 Black and 30 White pregnant adults in Kaiser Permanente Northern California, who self-reported prenatal cannabis use during early pregnancy. Focus groups were recorded, transcribed, and analyzed using thematic analysis. Results: The sample (N = 53) had a mean age of 30.3 years (standard deviation = 5.2) at recruitment; 70% reported daily, 25% weekly, and 6% ≤ monthly cannabis use at entrance to prenatal care. Some participants viewed cannabis as critical for coping with postpartum mental and physical health challenges, while others questioned whether cannabis use would fit with their parental lifestyle, and some planned to abstain altogether. Most planned to use cannabis postpartum, but with lower frequency than before pregnancy, and in ways consistent with harm reduction (e.g., smoking outside to avoid secondhand or thirdhand smoke exposure). Many were motivated to abstain from cannabis while breastfeeding, and some desired more data on the safety of cannabis and breastfeeding, or intended to "pump and dump," believing it would reduce potential transfer of Δ9-tetrahydrocannabinol (THC) to their infant. Responses from Black and White participants were generally similar, but White participants were more likely to report plans to use cannabis while breastfeeding and to want information about cannabis and breastfeeding. Conclusions: Pregnant individuals with prenatal cannabis use had varied plans for cannabis use postpartum. Many were motivated to abstain or use cannabis less frequently than pre-pregnancy, especially during lactation.

Patterns of Substance Use During Early Pregnancy and Associations With Behavioral Health Characteristics.

OBJECTIVES: The aims of the study are to identify patterns of early pregnancy substance use and to examine how these patterns relate to behavioral health conditions measured in early pregnancy. METHODS: We conducted a retrospective observational study (N= 265,274 pregnancies) screened for alcohol, cannabis, nicotine, pharmaceutical opioids, and stimulants during the first trimester via self-report and urine toxicology tests in Kaiser Permanente Northern California from January 1, 2012, to December 31, 2019. To identify patterns of prenatal substance use, we conducted latent class analysis. We then calculated the prevalence of depression, anxiety, intimate partner violence, and family drug use history for each prenatal substance use group and compared the prevalences by estimating prevalence ratios using modified Poisson regression, adjusting for sociodemographic characteristics. RESULTS: We identified the following 4 latent groups with different patterns of substance use: ( a ) predominantly alcohol and no other substances (9.30%), ( b ) predominantly cannabis and no other substances (4.88%), ( c ) predominantly nicotine and some pharmaceutical opioids (1.09%), and ( d ) high-polysubstance (alcohol, cannabis, nicotine, and stimulants; 0.36%); these pregnancies were compared with ( e ) no prenatal substance use (84.37%). The prevalence of all behavioral health conditions was elevated in all prenatal substance use groups compared with the no substance use group. Furthermore, the prevalence of depressive and anxiety disorders, intimate partner violence and family drug use history were greater in the high-polysubstance cluster than the alcohol and cannabis clusters. CONCLUSIONS: Results highlight the importance of screening and interventions for all types of substance use during early pregnancy and suggest a particularly high need to prioritize targeting early interventions to pregnant and reproductive age individuals with polysubstance use.

Pregnant individual's lived experience of cannabis use during the COVID-19 pandemic: a qualitative study.

Introduction: Quantitative studies indicate that the COVID-19 pandemic has contributed to increased rates of prenatal cannabis use. However, little is known about how the pandemic has impacted cannabis use from the perspective of pregnant individuals themselves. Our objective was to characterize COVID-19-related changes in cannabis use among pregnant individuals who used cannabis during the pandemic. Methods: We conducted 18 focus groups (from 11/17/2021 to 12/17/2021) with Black and White pregnant individuals aged 18+ who self-reported prenatal cannabis use during universal screening at entrance to prenatal care (at ~8 weeks gestation) in Kaiser Permanente Northern California. Virtual focus groups were transcribed and analyzed using thematic analysis. Results: The sample of 53 pregnant individuals (23 Black, 30 White) was 30.3 years old (SD = 5.2) on average, and most (70%) self-reported daily versus weekly or monthly prenatal cannabis use. Major themes regarding the impact of the pandemic on cannabis use included increases in use (resulting from depression, anxiety, stress, boredom), and changes in social use (less sharing of smoked cannabis products), modes of use (from smoking to other modes due to respiratory concerns) and source (from storefront retailers to delivery). Conclusion: Coping with mental health symptoms and stress were identified drivers of perceived pandemic-related increases in prenatal cannabis use in 2021. Pregnant individuals adapted their use in ways consistent with public health recommendations to decrease social contact and reduce or quit smoking to mitigate COVID-19 transmission and harms. Proactive, mental health outreach for pregnant individuals during future pandemic waves may reduce prenatal cannabis use.

The ETS transcription factor ETV6 constrains the transcriptional activity of EWS-FLI to promote Ewing sarcoma.

Transcription factors (TFs) are frequently mutated in cancer. Paediatric cancers exhibit few mutations genome-wide but frequently harbour sentinel mutations that affect TFs, which provides a context to precisely study the transcriptional circuits that support mutant TF-driven oncogenesis. A broadly relevant mechanism that has garnered intense focus involves the ability of mutant TFs to hijack wild-type lineage-specific TFs in self-reinforcing transcriptional circuits. However, it is not known whether this specific type of circuitry is equally crucial in all mutant TF-driven cancers. Here we describe an alternative yet central transcriptional mechanism that promotes Ewing sarcoma, wherein constraint, rather than reinforcement, of the activity of the fusion TF EWS-FLI supports cancer growth. We discover that ETV6 is a crucial TF dependency that is specific to this disease because it, counter-intuitively, represses the transcriptional output of EWS-FLI. This work discovers a previously undescribed transcriptional mechanism that promotes cancer.

Transcriptional Antagonism by CDK8 Inhibition Improves Therapeutic Efficacy of MEK Inhibitors.

Aberrant RAS/MAPK signaling is a common driver of oncogenesis that can be therapeutically targeted with clinically approved MEK inhibitors. Disease progression on single-agent MEK inhibitors is common, however, and combination therapies are typically required to achieve significant clinical benefit in advanced cancers. Here we focused on identifying MEK inhibitor-based combination therapies in neuroblastoma with mutations that activate the RAS/MAPK signaling pathway, which are rare at diagnosis but frequent in relapsed neuroblastoma. A genome-scale CRISPR-Cas9 functional genomic screen was deployed to identify genes that when knocked out sensitize RAS-mutant neuroblastoma to MEK inhibition. Loss of either CCNC or CDK8, two members of the mediator kinase module, sensitized neuroblastoma to MEK inhibition. Furthermore, small-molecule kinase inhibitors of CDK8 improved response to MEK inhibitors in vitro and in vivo in RAS-mutant neuroblastoma and other adult solid tumors. Transcriptional profiling revealed that loss of CDK8 or CCNC antagonized the transcriptional signature induced by MEK inhibition. When combined, loss of CDK8 or CCNC prevented the compensatory upregulation of progrowth gene expression induced by MEK inhibition. These findings propose a new therapeutic combination for RAS-mutant neuroblastoma and may have clinical relevance for other RAS-driven malignancies. SIGNIFICANCE: Transcriptional adaptation to MEK inhibition is mediated by CDK8 and can be blocked by the addition of CDK8 inhibitors to improve response to MEK inhibitors in RAS-mutant neuroblastoma, a clinically challenging disease.

BAF Complex Maintains Glioma Stem Cells in Pediatric H3K27M Glioma.

Diffuse midline gliomas are uniformly fatal pediatric central nervous system cancers that are refractory to standard-of-care therapeutic modalities. The primary genetic drivers are a set of recurrent amino acid substitutions in genes encoding histone H3 (H3K27M), which are currently undruggable. These H3K27M oncohistones perturb normal chromatin architecture, resulting in an aberrant epigenetic landscape. To interrogate for epigenetic dependencies, we performed a CRISPR screen and show that patient-derived H3K27M-glioma neurospheres are dependent on core components of the mammalian BAF (SWI/SNF) chromatin remodeling complex. The BAF complex maintains glioma stem cells in a cycling, oligodendrocyte precursor cell-like state, in which genetic perturbation of the BAF catalytic subunit SMARCA4 (BRG1), as well as pharmacologic suppression, opposes proliferation, promotes progression of differentiation along the astrocytic lineage, and improves overall survival of patient-derived xenograft models. In summary, we demonstrate that therapeutic inhibition of the BAF complex has translational potential for children with H3K27M gliomas. SIGNIFICANCE: Epigenetic dysregulation is at the core of H3K27M-glioma tumorigenesis. Here, we identify the BRG1-BAF complex as a critical regulator of enhancer and transcription factor landscapes, which maintain H3K27M glioma in their progenitor state, precluding glial differentiation, and establish pharmacologic targeting of the BAF complex as a novel treatment strategy for pediatric H3K27M glioma. See related commentary by Beytagh and Weiss, p. 2730. See related article by Mo et al., p. 2906.

Transition to a mesenchymal state in neuroblastoma confers resistance to anti-GD2 antibody via reduced expression of ST8SIA1.

Immunotherapy with anti-GD2 antibodies has advanced the treatment of children with high-risk neuroblastoma, but nearly half of patients relapse, and little is known about mechanisms of resistance to anti-GD2 therapy. Here, we show that reduced GD2 expression was significantly correlated with the mesenchymal cell state in neuroblastoma and that a forced adrenergic-to-mesenchymal transition (AMT) conferred downregulation of GD2 and resistance to anti-GD2 antibody. Mechanistically, low-GD2-expressing cell lines demonstrated significantly reduced expression of the ganglioside synthesis enzyme ST8SIA1 (GD3 synthase), resulting in a bottlenecking of GD2 synthesis. Pharmacologic inhibition of EZH2 resulted in epigenetic rewiring of mesenchymal neuroblastoma cells and re-expression of ST8SIA1, restoring surface expression of GD2 and sensitivity to anti-GD2 antibody. These data identify developmental lineage as a key determinant of sensitivity to anti-GD2 based immunotherapies and credential EZH2 inhibitors for clinical testing in combination with anti-GD2 antibody to enhance outcomes for children with neuroblastoma.

Trends in Cannabis Polysubstance Use During Early Pregnancy Among Patients in a Large Health Care System in Northern California.

Importance: Rates of prenatal cannabis use are increasing alongside perceptions that cannabis is a harmless therapeutic for pregnancy-related ailments, while rates of prenatal use of alcohol and tobacco are decreasing. It is important to examine whether cannabis use during pregnancy is increasing similarly among patients with and patients without co-occurring substance use. Objectives: To examine trends in cannabis polysubstance use during pregnancy and to test differences in cannabis use over time among pregnant individuals who use only cannabis vs those who use cannabis and other substances. Design, Setting, and Participants: This cross-sectional time-series study used data from 367 138 pregnancies among 281 590 unique pregnant patients universally screened for prenatal substance use as part of standard care in Kaiser Permanente Northern California from January 1, 2009, to December 31, 2018. Statistical analysis was performed from October 5, 2021, to April 18, 2022. Exposures: Time (calendar year). Main Outcomes and Measures: Use of substances during early pregnancy was assessed via universal screening with a self-administered questionnaire (for cannabis, alcohol, stimulants, and nicotine) and/or positive results of a urine toxicology test (for cannabis, alcohol, stimulants, and pharmaceutical opioids), and data were extracted from the electronic health record. Results: The study sample of 367 138 pregnancies from 281 590 unique pregnant patients (median gestation at time of screening, 8.6 weeks [IQR, 7.3-10.6 weeks]) was 25.9% Asian or Pacific Islander, 6.6% Black, 25.8% Hispanic, 38.0% non-Hispanic White, and 3.6% other race or ethnicity; 1.1% were aged 11 to 17 years, 14.9% were aged 18 to 24 years, 61.9% were aged 25 to 34 years, and 22.1% were aged 35 years or older; and the median neighborhood household income was $70 455 (IQR, $51 563-$92 625). From 2009 to 2018, adjusted rates of use of only cannabis during pregnancy (no other substances) increased substantially from 2.39% (95% CI, 2.20%-2.58%) in 2009 to 6.30% (95% CI, 6.00%-6.60%) in 2018, increasing at an annual relative rate of 1.11 (95% CI, 1.10-1.12). The rate of use of cannabis and 1 other substance also increased (annual relative rate, 1.04 [95% CI, 1.03-1.05]), but not as rapidly (P < .001 for difference), while the rate of use of cannabis and 2 or more other substances decreased slightly (annual relative rate, 0.97 [95% CI, 0.96-0.99]). Adjusted rates of prenatal use of cannabis and alcohol (1.04 [95% CI, 1.03-1.06]) and cannabis and stimulants (1.03 [95% CI, 1.01-1.06]) increased over time, while rates of prenatal use of cannabis and nicotine (0.97 [95% CI, 0.96-0.98]) decreased. Conclusions and Relevance: In this cross-sectional time-series study, rates of prenatal cannabis use during early pregnancy increased significantly more rapidly among patients without co-occurring substance use, which could reflect increased acceptability of cannabis and decreased perceptions of cannabis-related harms. Furthermore, increased rates of use of cannabis with alcohol and stimulants warrant continued monitoring.

Unleashing Cell-Intrinsic Inflammation as a Strategy to Kill AML Blasts.

Leukemic blasts are immune cells gone awry. We hypothesized that dysregulation of inflammatory pathways contributes to the maintenance of their leukemic state and can be exploited as cell-intrinsic, self-directed immunotherapy. To this end, we applied genome-wide screens to discover genetic vulnerabilities in acute myeloid leukemia (AML) cells implicated in inflammatory pathways. We identified the immune modulator IRF2BP2 as a selective AML dependency. We validated AML cell dependency on IRF2BP2 with genetic and protein degradation approaches in vitro and genetically in vivo. Chromatin and global gene-expression studies demonstrated that IRF2BP2 represses IL1ß/TNFα signaling via NFκB, and IRF2BP2 perturbation results in an acute inflammatory state leading to AML cell death. These findings elucidate a hitherto unexplored AML dependency, reveal cell-intrinsic inflammatory signaling as a mechanism priming leukemic blasts for regulated cell death, and establish IRF2BP2-mediated transcriptional repression as a mechanism for blast survival. SIGNIFICANCE: This study exploits inflammatory programs inherent to AML blasts to identify genetic vulnerabilities in this disease. In doing so, we determined that AML cells are dependent on the transcriptional repressive activity of IRF2BP2 for their survival, revealing cell-intrinsic inflammation as a mechanism priming leukemic blasts for regulated cell death. See related commentary by Puissant and Medyouf, p. 1617. This article is highlighted in the In This Issue feature, p. 1599.

Modes of cannabis administration in the year prior to conception among patients in Northern California.

Cannabis use among individuals before and during pregnancy is increasing alongside the proliferation of new products with various modes of administration. Preconception cannabis use is a strong predictor of prenatal cannabis use. Yet little is known about how individuals administer cannabis during the preconception period, particularly in socioeconomically vulnerable populations. This study examined the prevalence and correlates of modes of cannabis administration (smoke, vape, blunts, edible/oral, dabs/wax, lotion/topical) during the year before conception, among patients who self-reported preconception cannabis use during universal screening in prenatal care. Descriptive statistics included sociodemographic characteristics, preconception cannabis use frequency, and modes of administration. Chi-square tests examined whether mode was associated with sociodemographic characteristics and use frequency. The sample (N = 11,936, screened from February 2020-May 2021) was 59.8% non-White and 26.1% were < 26 years old; 50.7% reported monthly or less, 21.8% weekly, and 27.4% daily preconception cannabis use; 69.7% smoked (any method), 34.5% smoked blunts, 53.4% used edibles/oral, 28.2% vaped, 9.9% used lotion/topical; 54.2% reported 1 mode, 30.4% reported 2 modes, 15.4% reported 3+ modes. Smoking was more common among daily users, younger patients, those with greater neighborhood deprivation, and Black and Hispanic patients, while edibles/oral were more common among ≤ monthly users, older patients, those with less neighborhood deprivation, and Asian patients. Use of other modes also varied by sociodemographic characteristics and use frequency. Research is needed to understand preconception cannabis use in vulnerable subpopulations, continuation of use during pregnancy, and whether health risks associated with preconception and prenatal cannabis use differ by administration mode.

EP300 Selectively Controls the Enhancer Landscape of MYCN-Amplified Neuroblastoma.

Gene expression is regulated by promoters and enhancers marked by histone H3 lysine 27 acetylation (H3K27ac), which is established by the paralogous histone acetyltransferases (HAT) EP300 and CBP. These enzymes display overlapping regulatory roles in untransformed cells, but less characterized roles in cancer cells. We demonstrate that the majority of high-risk pediatric neuroblastoma (NB) depends on EP300, whereas CBP has a limited role. EP300 controls enhancer acetylation by interacting with TFAP2ß, a transcription factor member of the lineage-defining transcriptional core regulatory circuitry (CRC) in NB. To disrupt EP300, we developed a proteolysis-targeting chimera (PROTAC) compound termed "JQAD1" that selectively targets EP300 for degradation. JQAD1 treatment causes loss of H3K27ac at CRC enhancers and rapid NB apoptosis, with limited toxicity to untransformed cells where CBP may compensate. Furthermore, JQAD1 activity is critically determined by cereblon (CRBN) expression across NB cells. SIGNIFICANCE: EP300, but not CBP, controls oncogenic CRC-driven transcription in high-risk NB by binding TFAP2ß. We developed JQAD1, a CRBN-dependent PROTAC degrader with preferential activity against EP300 and demonstrated its activity in NB. JQAD1 has limited toxicity to untransformed cells and is effective in vivo in a CRBN-dependent manner. This article is highlighted in the In This Issue feature, p. 587.

An In Vivo CRISPR Screening Platform for Prioritizing Therapeutic Targets in AML.

CRISPR-Cas9-based genetic screens have successfully identified cell type-dependent liabilities in cancer, including acute myeloid leukemia (AML), a devastating hematologic malignancy with poor overall survival. Because most of these screens have been performed in vitro using established cell lines, evaluating the physiologic relevance of these targets is critical. We have established a CRISPR screening approach using orthotopic xenograft models to validate and prioritize AML-enriched dependencies in vivo, including in CRISPR-competent AML patient-derived xenograft (PDX) models tractable for genome editing. Our integrated pipeline has revealed several targets with translational value, including SLC5A3 as a metabolic vulnerability for AML addicted to exogenous myo-inositol and MARCH5 as a critical guardian to prevent apoptosis in AML. MARCH5 repression enhanced the efficacy of BCL2 inhibitors such as venetoclax, further highlighting the clinical potential of targeting MARCH5 in AML. Our study provides a valuable strategy for discovery and prioritization of new candidate AML therapeutic targets. SIGNIFICANCE: There is an unmet need to improve the clinical outcome of AML. We developed an integrated in vivo screening approach to prioritize and validate AML dependencies with high translational potential. We identified SLC5A3 as a metabolic vulnerability and MARCH5 as a critical apoptosis regulator in AML, both of which represent novel therapeutic opportunities.This article is highlighted in the In This Issue feature, p. 275.

Targeting serine hydroxymethyltransferases 1 and 2 for T-cell acute lymphoblastic leukemia therapy.

Despite progress in the treatment of acute lymphoblastic leukemia (ALL), T-cell ALL (T-ALL) has limited treatment options, particularly in the setting of relapsed/refractory disease. Using an unbiased genome-scale CRISPR-Cas9 screen we sought to identify pathway dependencies for T-ALL which could be harnessed for therapy development. Disruption of the one-carbon folate, purine and pyrimidine pathways scored as the top metabolic pathways required for T-ALL proliferation. We used a recently developed inhibitor of SHMT1 and SHMT2, RZ-2994, to characterize the effect of inhibiting these enzymes of the one-carbon folate pathway in T-ALL and found that T-ALL cell lines were differentially sensitive to RZ-2994, with the drug inducing a S/G2 cell cycle arrest. The effects of SHMT1/2 inhibition were rescued by formate supplementation. Loss of both SHMT1 and SHMT2 was necessary for impaired growth and cell cycle arrest, with suppression of both SHMT1 and SHMT2 inhibiting leukemia progression in vivo. RZ-2994 also decreased leukemia burden in vivo and remained effective in the setting of methotrexate resistance in vitro. This study highlights the significance of the one-carbon folate pathway in T-ALL and supports further development of SHMT inhibitors for treatment of T-ALL and other cancers.

TRIM8 modulates the EWS/FLI oncoprotein to promote survival in Ewing sarcoma.

Fusion-transcription factors (fusion-TFs) represent a class of driver oncoproteins that are difficult to therapeutically target. Recently, protein degradation has emerged as a strategy to target these challenging oncoproteins. The mechanisms that regulate fusion-TF stability, however, are generally unknown. Using CRISPR-Cas9 screening, we discovered tripartite motif-containing 8 (TRIM8) as an E3 ubiquitin ligase that ubiquitinates and degrades EWS/FLI, a driver fusion-TF in Ewing sarcoma. Moreover, we identified TRIM8 as a selective dependency in Ewing sarcoma compared with >700 other cancer cell lines. Mechanistically, TRIM8 knockout led to an increase in EWS/FLI protein levels that was not tolerated. EWS/FLI acts as a neomorphic substrate for TRIM8, defining the selective nature of the dependency. Our results demonstrate that fusion-TF protein stability is tightly regulated and highlight fusion oncoprotein-specific regulators as selective therapeutic targets. This study provides a tractable strategy to therapeutically exploit oncogene overdose in Ewing sarcoma and potentially other fusion-TF-driven cancers.

STAG2 loss rewires oncogenic and developmental programs to promote metastasis in Ewing sarcoma.

The core cohesin subunit STAG2 is recurrently mutated in Ewing sarcoma but its biological role is less clear. Here, we demonstrate that cohesin complexes containing STAG2 occupy enhancer and polycomb repressive complex (PRC2)-marked regulatory regions. Genetic suppression of STAG2 leads to a compensatory increase in cohesin-STAG1 complexes, but not in enhancer-rich regions, and results in reprogramming of cis-chromatin interactions. Strikingly, in STAG2 knockout cells the oncogenic genetic program driven by the fusion transcription factor EWS/FLI1 was highly perturbed, in part due to altered enhancer-promoter contacts. Moreover, loss of STAG2 also disrupted PRC2-mediated regulation of gene expression. Combined, these transcriptional changes converged to modulate EWS/FLI1, migratory, and neurodevelopmental programs. Finally, consistent with clinical observations, functional studies revealed that loss of STAG2 enhances the metastatic potential of Ewing sarcoma xenografts. Our findings demonstrate that STAG2 mutations can alter chromatin architecture and transcriptional programs to promote an aggressive cancer phenotype.

Targeting acute myeloid leukemia dependency on VCP-mediated DNA repair through a selective second-generation small-molecule inhibitor.

The development and survival of cancer cells require adaptive mechanisms to stress. Such adaptations can confer intrinsic vulnerabilities, enabling the selective targeting of cancer cells. Through a pooled in vivo short hairpin RNA (shRNA) screen, we identified the adenosine triphosphatase associated with diverse cellular activities (AAA-ATPase) valosin-containing protein (VCP) as a top stress-related vulnerability in acute myeloid leukemia (AML). We established that AML was the most responsive disease to chemical inhibition of VCP across a panel of 16 cancer types. The sensitivity to VCP inhibition of human AML cell lines, primary patient samples, and syngeneic and xenograft mouse models of AML was validated using VCP-directed shRNAs, overexpression of a dominant-negative VCP mutant, and chemical inhibition. By combining mass spectrometry-based analysis of the VCP interactome and phospho-signaling studies, we determined that VCP is important for ataxia telangiectasia mutated (ATM) kinase activation and subsequent DNA repair through homologous recombination in AML. A second-generation VCP inhibitor, CB-5339, was then developed and characterized. Efficacy and safety of CB-5339 were validated in multiple AML models, including syngeneic and patient-derived xenograft murine models. We further demonstrated that combining DNA-damaging agents, such as anthracyclines, with CB-5339 treatment synergizes to impair leukemic growth in an MLL-AF9-driven AML murine model. These studies support the clinical testing of CB-5339 as a single agent or in combination with standard-of-care DNA-damaging chemotherapy for the treatment of AML.

Selective Modulation of a Pan-Essential Protein as a Therapeutic Strategy in Cancer.

Cancer dependency maps, which use CRISPR/Cas9 depletion screens to profile the landscape of genetic dependencies in hundreds of cancer cell lines, have identified context-specific dependencies that could be therapeutically exploited. An ideal therapy is both lethal and precise, but these depletion screens cannot readily distinguish between gene effects that are cytostatic or cytotoxic. Here, we use a diverse panel of functional genomic screening assays to identify NXT1 as a selective and rapidly lethal in vivo relevant genetic dependency in MYCN-amplified neuroblastoma. NXT1 heterodimerizes with NXF1, and together they form the principal mRNA nuclear export machinery. We describe a previously unrecognized mechanism of synthetic lethality between NXT1 and its paralog NXT2: their common essential binding partner NXF1 is lost only in the absence of both. We propose a potential therapeutic strategy for tumor-selective elimination of a protein that, if targeted directly, is expected to cause widespread toxicity. SIGNIFICANCE: We provide a framework for identifying new therapeutic targets from functional genomic screens. We nominate NXT1 as a selective lethal target in neuroblastoma and propose a therapeutic approach where the essential protein NXF1 can be selectively eliminated in tumor cells by exploiting the NXT1-NXT2 paralog relationship.See related commentary by Wang and Abdel-Wahab, p. 2129.This article is highlighted in the In This Issue feature, p. 2113.

Matched Targeted Therapy for Pediatric Patients with Relapsed, Refractory, or High-Risk Leukemias: A Report from the LEAP Consortium.

Despite a remarkable increase in the genomic profiling of cancer, integration of genomic discoveries into clinical care has lagged behind. We report the feasibility of rapid identification of targetable mutations in 153 pediatric patients with relapsed/refractory or high-risk leukemias enrolled on a prospective clinical trial conducted by the LEAP Consortium. Eighteen percent of patients had a high confidence Tier 1 or 2 recommendation. We describe clinical responses in the 14% of patients with relapsed/refractory leukemia who received the matched targeted therapy. Further, in order to inform future targeted therapy for patients, we validated variants of uncertain significance, performed ex vivo drug-sensitivity testing in patient leukemia samples, and identified new combinations of targeted therapies in cell lines and patient-derived xenograft models. These data and our collaborative approach should inform the design of future precision medicine trials. SIGNIFICANCE: Patients with relapsed/refractory leukemias face limited treatment options. Systematic integration of precision medicine efforts can inform therapy. We report the feasibility of identifying targetable mutations in children with leukemia and describe correlative biology studies validating therapeutic hypotheses and novel mutations.See related commentary by Bornhauser and Bourquin, p. 1322.This article is highlighted in the In This Issue feature, p. 1307.

Rapid and direct control of target protein levels with VHL-recruiting dTAG molecules.

Chemical biology strategies for directly perturbing protein homeostasis including the degradation tag (dTAG) system provide temporal advantages over genetic approaches and improved selectivity over small molecule inhibitors. We describe dTAGV-1, an exclusively selective VHL-recruiting dTAG molecule, to rapidly degrade FKBP12F36V-tagged proteins. dTAGV-1 overcomes a limitation of previously reported CRBN-recruiting dTAG molecules to degrade recalcitrant oncogenes, supports combination degrader studies and facilitates investigations of protein function in cells and mice.

Trends and correlates of self-reported alcohol and nicotine use among women before and during pregnancy, 2009-2017.

OBJECTIVE: To examine trends and correlates of frequency of self-reported alcohol and nicotine use among pregnant women. METHODS: Cross-sectional study of 363,240 pregnancies from 2009 to 2017 screened for self-reported substance use at their first prenatal visit in Kaiser Permanente Northern California. Poisson regression with a log link function was used to estimate the annual prevalences of self-reported daily, weekly, and ≤ monthly alcohol and nicotine use, adjusting for socio-demographics. Generalized estimating equation models were used to estimate the adjusted odds ratios (aOR) of any self-reported prenatal alcohol or nicotine use among those who self-reported use in the year prior to pregnancy, by frequency of pre-pregnancy substance use and socio-demographics. RESULTS: The sample was 64 % non-White [mean (SD) age = 30.1 (5.6)]. From 2009-2017, alcohol use before pregnancy increased from 63.4%-65.9% (trend p-value = .008), and prenatal alcohol use decreased from 11.6%-8.8% (trend p-value<.0001). Nicotine use before pregnancy decreased from 12.7 % to 7.7 % (trend p-value<.0001), and prenatal use decreased from 4.3 % to 2.0 % (trend p-value<.0001). Trends by use frequency were similar to overall trends. The odds of continued use of alcohol and nicotine during pregnancy were higher among those who used daily or weekly (versus monthly or less) in the year before pregnancy and varied with socio-demographics. DISCUSSION: Prenatal alcohol and nicotine use decreased from 2009 to 2017. More frequent pre-pregnancy use predicted higher odds of prenatal use. Results suggest that interventions and education about the harms of prenatal substance use for frequent users prior to conception may reduce substance use during pregnancy.