Decker, Paul A.

Establishing causal links between inherited polymorphisms and cancer risk is challenging. Here, we focus on the single-nucleotide polymorphism rs55705857, which confers a sixfold greater risk of isocitrate dehydrogenase ( IDH) –mutant low-grade glioma (LGG). We reveal that rs55705857 itself is the causal variant and is associated with molecular pathways that drive LGG. Mechanistically, we show that rs55705857 resides within a brain-specific enhancer, where the risk allele disrupts OCT2/4 binding, allowing increased interaction with the Myc promoter and increased Myc expression. Mutating the orthologous mouse rs55705857 locus accelerated tumor development in an Idh1 R132H -driven LGG mouse model from 472 to 172 days and increased penetrance from 30% to 75%. Our work reveals mechanisms of the heritable predisposition to lethal glioma in ~40% of LGG patients.

AbstractIntroductionThere is some evidence that social media interventions can promote smoking cessation. This randomized controlled pilot study is the first to evaluate the feasibility and potential efficacy of a Facebook smoking cessation intervention among Alaska Native (AN) adults.Aims and MethodsRecruitment and data collection occurred from December 2019 to March 2021. Participants were recruited statewide in Alaska using Facebook advertisements with a targeted sample of 60 enrolled. Participants were stratified by gender, age, and rural or urban residence and randomly assigned to receive referral resources on evidence-based cessation treatments (EBCTs) (control, n = 30) or these resources plus a 3-month, closed (private), culturally tailored, Facebook group (intervention, n = 31) that connected participants to EBCT resources and was moderated by two Alaska Native Trained Tobacco Specialists. Assessments were conducted online post-randomization at 1, 3, and 6 months. Outcomes were feasibility (recruitment, retention, and intervention engagement), self-reported use of EBCTs, and biochemically confirmed seven-day point-prevalence smoking abstinence.ResultsOf intervention participants, 90% engaged (eg posted, commented) more than once. Study retention was 57% at 6 months (no group differences). The proportion utilizing EBCTs was about double for intervention compared with the control group participants at 3 and 6 months. Smoking abstinence was higher for intervention than control participants at 3 months (6.5% vs. 0%, p = .16) but comparable at 6 months (6.4% vs. 6.7%, p = .97).ConclusionsWhile additional research is needed to promote long-term cessation, this pilot trial supports recruitment feasibility during the Coronavirus Disease 2019 (COVID-19) pandemic, consumer uptake, and a signal for intervention efficacy on the uptake of cessation treatment and short-term smoking abstinence.ImplicationsThis study is the first evaluation of a social media intervention for smoking cessation among Indigenous people. We learned that statewide Facebook recruitment of AN adults who smoke was feasible and there was a signal for the efficacy of a Facebook intervention on the uptake of EBCT and short-term (3 months) biochemically verified smoking abstinence. Clinically, social media platforms may complement current care models by connecting AN individuals and others living in hard-to-reach communities to cessation treatment resources.

Abstract Background Risk factors for the pathogenesis of chronic rhinosinusitis (CRS) remain largely undetermined, which is likely due to the heterogeneity of the disease. White blood cell counts have been largely unexplored as a risk factor for CRS even though different types of white blood cells are involved in the inflammatory process of CRS. Objective To investigate causal associations between different types of white blood cells on risk of CRS utilizing a Mendelian randomization (MR) analysis. Methods A two-sample MR analysis was performed using respective GWAS summary statistics for the exposure traits (neutrophil count, eosinophil count, basophil count, lymphocyte count, and monocyte count) and outcome trait (CRS). For the exposure traits, the European Bioinformatics Institute database of complete GWAS summary data was used. For the outcome trait, summary statistics for CRS GWAS were obtained from FinnGen. Primary analysis for MR was performed using inverse-variance weighted two-sample MR. Sensitivity analyses included weighted median, MR-Egger, and MR-PRESSO (raw and outlier-corrected). Results Eosinophils were associated with CRS (OR = 1.55 [95%CI 1.38,1.73]; p = 4.3E-14). Eosinophil results were similar across additional MR methods. MR results did not demonstrate significant causal relationships between neutrophils, lymphocytes, monocytes, or basophils with CRS. No significant pleiotropic bias was observed. Conclusions In a two-sample MR analysis, a potential causal link between blood eosinophil counts and CRS has been demonstrated. In addition, causal relationships between blood counts among other white blood cell types and CRS were not found. Further studies involving genetic variation in CRS are needed to corroborate genetic causal effects for CRS.

Abstract Background EGFR targeting antibody-drug conjugates (ADCs) are highly effective against EGFR-amplified tumors, but poor distribution across the blood–brain barrier (BBB) limits their efficacy in glioblastoma (GBM) when administered systemically. We studied whether convection-enhanced delivery (CED) can be used to safely infuse ADCs into orthotopic patient-derived xenograft (PDX) models of EGFRvIII mutant GBM. Methods The efficacy of the EGFR-targeted ADCs depatuxizumab mafodotin (Depatux-M) and Serclutamab talirine (Ser-T) was evaluated in vitro and in vivo. CED was performed in nontumor and tumor-bearing mice. Immunostaining was used to evaluate ADC distribution, pharmacodynamic effects, and normal cell toxicity. Results Dose-finding studies in orthotopic GBM6 identified single infusion of 2 μg Ser-T and 60 μg Depatux-M as safe and effective associated with extended survival prolongation (>300 days and 95 days, respectively). However, with serial infusions every 21 days, four Ser-T doses controlled tumor growth but was associated with lethal toxicity approximately 7 days after the final infusion. Limiting dosing to two infusions in GBM108 provided profound median survival extension of over 200 days. In contrast, four Depatux-M CED doses were well tolerated and significantly extended survival in both GBM6 (158 days) and GBM108 (310 days). In a toxicity analysis, Ser-T resulted in a profound loss in NeuN+ cells and markedly elevated GFAP staining, while Depatux-M was associated only with modest elevation in GFAP staining. Conclusion CED of Depatux-M is well tolerated and results in extended survival in orthotopic GBM PDXs. In contrast, CED of Ser-T was associated with a much narrower therapeutic window.

Abstract The Mayo Clinic collection of patient-derived xenograft (PDXs) has been developed from the direct implantation of glioblastoma (GBM) samples into immunodeficient mice. Over 105 models have been extensively characterized with regards to histology, invasion, flank and orthotopic growth rates, and molecular profiling. Evaluation of orthotopic tumors demonstrated infiltration of tumor cells into the brain parenchymal in 90% of models with contralateral hemisphere involvement in 64%. Extensive molecular profiling confirmed the PDX collection captures the genetic heterogeneity of GBM, with the majority of typical molecular alterations seen at a frequency similar to the TCGA including gain of chromosome 7 and loss of chromosome 10. TERT promoter mutations (86%) and homozygous deletion of CDKN2A (70%) were the most frequent. Additional alterations in the p53 pathway included TP53 mutations (36%) and MDM2/4 amplification (10%/2%). IDH mutations were found in three models while MGMT promoter methylation was observed in 45% of PDXs. The available molecular sequencing results are viewable on cBioPortal. These genetically diverse models are extremely useful for biomarker discovery and efficacy evaluations. Using an innovative 1x1x1 PDX preclinical trial design, we are establishing a workflow to evaluate control and drug treatment in an individual animal across PDX lines in the flank. As our first use of this strategy, a small molecule MDM2 inhibitor was evaluated in 17 PDX lines with variable MDM2 and TP53 statuses. Tumors harboring MDM2 amplification without TP53 mutation (n=5) showed profound response, with 4 PDXs showing a complete response that lasted >150 days. Response in TP53 wild-type tumors lacking MDM2 amplification was variable, with a 1.9 to 4.8 fold longer time to endpoint (mean 3; median 2.7). A more traditionally powered intracranial efficacy study performed with one MDM2 amplified (GBM108) and two non-amplified (GBM14, GBM10) PDX lines confirmed these findings of reduced and more variable response to therapy in MDM2 non-amplified TP53 wild-type tumors. Future studies will aim to examine novel biomarkers indicative of therapeutic response to better understand molecular features associated with MDM2 inhibitor efficacy. With over 20 years of experience, our group has extensive expertise in development of clinically relevant study designs focused on examining efficacy, tolerability, and pharmacokinetic/pharmacodynamic assessments. Our diverse collection of clinically relevant GBM PDX models provides a highly sought-after resource which has been utilized by the pharmaceutical community with 58 working relationships to date (26 contracts, 32 collaborations). Through these collaborations, we aim to expand the use of our highly characterized GBM PDX panel for biomarker discovery using similar strategies. Citation Format: Danielle M. Burgenske, Ann C. Mladek, Shulan Tian, Mark A. Schroeder, Zeng Hu, Brett L. Carlson, Paul A. Decker, Jeanette E. Eckel-Passow, Rachael Vaubel, Jann N. Sarkaria. Evaluation of novel therapeutics using the Mayo Clinic GBM Patient-Derived Xenograft (PDX) collection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4001.

Abstract Introduction: EGFR targeted antibody-drug conjugates (ADCs) show promise as a novel treatment in a subset of glioblastoma (GBM). Two EGFR targeting ADCs include first generation Depatux-M, with an antimitotic toxin monomethyl auristatin F (MMAF), and ABBV-321, with a DNA crosslinking agent pyrrolobenzodiazepine dimer (PBD) toxin. Due to the large molecular weight, poor drug distribution across the blood-brain barrier significantly limits the efficacy in EGFR-amplified GBM. We studied whether convection enhanced delivery (CED) can be used to safely infuse these two EGFR-targeted ADCs in patient-derived xenograft (PDX) models of EGFR-amplified GBM. Methods: The efficacy of Depatux-M and ABBV-321 was evaluated in vitro and in vivo in two EGFRviii-amplified PDXs (GBM6 and GBM108). Immunofluorescence staining was used to evaluate drug distribution along with pharmacodynamics of the ADCs. CED was performed by stereotactic placement of an infusion catheter in the same location as the original tumor implantation. Immunohistochemistry was used to explore mechanisms of normal cell toxicity. Results: Despite potent activity in vitro (high ng/ml IC50), systemic administration of either ADC conferred minimal extension in survival for either GBM6 or GBM108. In contrast, CED significantly enhanced ADC delivery to tumor and peri-tumoral regions and extended survival. In a pilot study in GBM6 with n=3 mice per group, a single CED infusion of 0.002mg ABBV-321 resulted in extended survival beyond 365 days for two mice, while other doses and placebo were associated with shorter median survival (0 mg - 39 days; 0.03 mg - 105 days; 0.3 mg - 49 days). In a subsequent trial evaluating serial infusions performed every 21 days, four infusions at 0.002 mg ABBV-321 resulted in lethal toxicity. In contrast, limiting ABBV-321 to only two serial CED infusions in GBM108 was associated with extended survival of more than 300 days vs. 53 days for AB095 antibody control infusion. In contrast, serial infusion with Depatux-M was much better tolerated. In a single infusion in GBM6, a 0.06 mg dose was well tolerated and associated with a 49-day extension in median survival. Further, four serial infusions at 0.06 mg given every 21 days in GBM6 and GBM108 was associated with 100 day and more than 250-day extension in survival as compared to AB095 antibody control infusion. To investigate the mechanism of toxicity, infusion of non-tumor bearing C57Bl6 mice with ABBV-321 resulted in a marked loss in NeuN staining and elevated CD68 and GFAP staining 7 days later; Depatux-M infusion was only associated with modest elevation in GFAP without loss of NeuN staining or elevated CD68-positive cells. Conclusion: Depatux-M is well tolerated when infused into normal brain and results in extended survival in orthotopic GBM PDXs. In contrast, ABBV-321, with a distinct PBD toxin, had a much narrower therapeutic window when delivered by CED. Citation Format: Kendra A. Porath, Ann Mladek, Rachael A. Vaubel, Michael S. Regan, Sonia Jain, Danielle Burgenske, Katrina Bakken, Brett Carlson, Margaret Connors, Zeng Hu, Lihong He, Paul A. Decker, Gaspar Kitange, Shiv Gupta, Nathalie Y. Agar, Thomas M. Feldsien, Didier R. Lefebvre, Jann N. Sarkaria. Convection enhanced delivery of EGFR-targeting antibody drug conjugates ABBV-321 and Depatux-M [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 334.

Abstract Glioblastoma (GBM) is a rapidly fatal malignancy typically treated with radiation and temozolomide (TMZ), an alkylating chemotherapeutic. These cytotoxic therapies cause oxidative stress and DNA damage, yielding a senescent-like state of replicative arrest in surviving tumor cells. Unfortunately, recurrence is inevitable and may be driven by surviving tumor cells eventually escaping senescence. A growing number of so-called “senolytic” drugs have been recently identified that are defined by their ability to selectively eliminate senescent cells. A growing inventory of senolytic drugs is under consideration for several diseases associated with aging, inflammation, DNA damage, as well as cancer. Ablation of senescent tumor cells after radiation and chemotherapy could help mitigate recurrence by decreasing the burden of residual tumor cells at risk of recurrence. This strategy has not been previously explored for GBM. We evaluated a panel of 10 previously described senolytic drugs to determine whether any could exhibit selective activity against human GBM persisting after exposure to radiation or TMZ. Three of the 10 drugs have known activity against BCL-XL and preferentially induced apoptosis in radiated or TMZ-treated glioma. This senolytic activity was observed in 12 of 12 human GBM cell lines. Efficacy could not be replicated with BCL-2 inhibition or senolytic agents acting against other putative senolytic targets. Knockdown of BCL-XL decreased survival of radiated GBM cells, whereas knockdown of BCL-2 or BCL-W yielded no senolytic effect. Implications: These findings imply that molecularly heterogeneous GBM lines share selective senescence-induced BCL-XL dependency increase the significance and translational relevance of the senolytic therapy for latent glioma.

Background Hepatocyte growth factor (HGF) is a biomarker with potential for use in the diagnosis, treatment and prognostication of cardiovascular disease (CVD). Elevated HGF is associated with calcification in the coronary arteries. However, knowledge is limited on the role HGF may play in extracoronary calcification (ECC). This study examined whether HGF is associated with ECC in the aortic valve (AVC), mitral annulus (MAC), ascending thoracic aorta and descending thoracic aortic (DTAC). Methods At baseline, adults aged 45–84 years, free of CVD, in the Multi-Ethnic Study of Atherosclerosis had HGF and ECC measured by ELISA and cardiac CT scan, respectively. ECC measurements were repeated after an average of 2.4 years of follow-up. Prevalent ECC was defined as Agatston score >0 at baseline. Incident ECC was defined as Agatston score >0 at follow-up among participants with Agatston score=0 at baseline. We used Poisson and linear mixed-effects regression models to estimate the association between HGF and ECC, adjusted for sociodemographic and CVD risk factors. Results Of 6648 participants, 53% were women. Mean (SD) age was 62 (10) years. Median (IQR) of HGF was 905 (757-1087) pg/mL. After adjustment for CVD risk factors, the highest HGF levels (tertile 3) were associated with greater prevalence and extent of AVC, MAC and DTAC at baseline compared with the lowest tertile (tertile 1). Additionally, the risk of incident AVC and MAC increased by 62% and 45%, respectively, in demographic-adjusted models. However, the associations were not statistically significant in fully adjusted models. The highest HGF levels were also associated with 10% and 13% increase in MAC and DTAC progression, respectively, even after adjustment for CVD risk factors. Conclusion Higher HGF levels were significantly associated with a greater risk of calcification at some extracoronary sites, suggesting an alternate biological pathway that could be targeted to reduce CVD risk.

Abstract Background H3K27M-mutant diffuse midline glioma (DMG) is a lethal brain tumor that usually occurs in children. Despite advances in our understanding of its underlying biology, efficacious therapies are severely lacking. Methods We screened a library of drugs either FDA-approved or in clinical trial using a library of patient-derived H3K27M-mutant DMG cell lines with cell viability as the outcome. Results were validated for clinical relevance and mechanistic importance using patient specimens from biopsy and autopsy, patient-derived cell lines, inhibition by gene knockdown and small molecule inhibitors, and patient-derived xenografts. Results Kinase inhibitors were highly toxic to H3K27M-mutant DMG cells. Within this class, STAT3 inhibitors demonstrated robust cytotoxic activity in vitro. Mechanistic analyses revealed one form of activated STAT3, phospho-tyrosine- 705 STAT3 (pSTAT3), was selectively upregulated in H3K27M-mutant cell lines and clinical specimens. STAT3 inhibition by CRISPR/Cas9 knockout, shRNA or small molecule inhibition reduced cell viability in vitro, and partially restored expression of the polycomb repressive mark H3K27me3, which is classically lost in H3K27M-mutant DMG. Putative STAT3-regulated genes were enriched in an H3K27M-knockout DMG cell line, indicating relative gain of STAT3 signaling in K27M-mutant cells. Treatment of patient-derived intracranial xenografts with WP1066, a STAT3 pathway inhibitor currently in clinical use for pediatric brain tumors, resulted in stasis of tumor growth, and increased overall survival. Finally, pSTAT3(Y705) was detected in circulating plasma extracellular vesicles of patients with H3K27M-mutant DMG. Conclusions STAT3 is a biologically relevant therapeutic target in H3K27M-mutant DMG. STAT3 inhibition should be considered in future clinical trials.

Introduction: Hepatocyte growth factor (HGF) is released in response to endothelial injury, and higher levels of circulating HGF are associated with atherosclerosis. However, the association of HGF with atherosclerosis progression is unknown. Hypothesis: Circulating HGF is positively associated with atherosclerosis progression, measured as progression of 1) carotid artery plaque and 2) coronary artery calcium (CAC). Methods: The Multi-Ethnic Study of Atherosclerosis is a large, population-based cohort study of adults aged 45-84 and free of clinical cardiovascular disease. Participants had HGF measured in serum at baseline (2000-02), and were followed for progression of carotid plaque and CAC through 2012. We defined CAC and carotid plaque progression as dichotomous variables (progression, no progression). Carotid plaque progression is an increase in the number of carotid plaques. We used the Hokanson method to define CAC progression as an increase of ≥ 2.5 mm 3 in the square root-transformed calcium volume score. Relative risk regression quantified the association between HGF and carotid plaque progression. Cox regression models using inverse-probability-of-attrition weights estimated the association of HGF with progression of CAC. All effect estimates are adjusted for potential confounding variables. Results: The cohort included 6714 Americans with HGF measurements: 2593 non-Hispanic white, 797 Chinese, 1848 black, and 1476 Hispanic Americans. In 3363 participants with measurements for both carotid plaque and HGF, each standard deviation (259 pg/ml) increase in HGF was associated with a 4% greater risk (95% CI: 1.01-1.07) of carotid plaque progression (n=1875), which did not differ by race/ethnicity (interaction p = 0.3). Out of 6714 participants with measurements for both CAC and HGF, 2994 had CAC progression during follow-up. The association of HGF with CAC progression differed by race/ethnicity (interaction p = 0.01). Each standard deviation increase of HGF was associated with a 10% greater risk of CAC progression in non-Hispanic white (95% CI: 1.05-1.16) and black Americans (95% CI: 1.03-1.17), while HGF was not associated with CAC progression in Chinese (p = 0.5) nor Hispanic (p = 0.7) American participants. Conclusions: Circulating HGF was associated with a modestly increased risk of atherosclerosis progression in this large and diverse population, with the strongest associations between HGF and CAC progression in non-Hispanic white and black Americans. Our results suggest that HGF may have utility as a marker of atherosclerosis progression in some populations.