Citations

Abstract Brain metabolism perturbation can contribute to traits and diseases. We conducted the first large-scale CSF and brain genome-wide association studies, which identified 219 independent associations (59.8% novel) for 144 CSF metabolites and 36 independent associations (55.6% novel) for 34 brain metabolites. Most of the novel signals (97.7% and 70.0% in CSF and brain) were tissue specific. We also integrated MWAS-FUSION approaches with Mendelian Randomization and colocalization to identify causal metabolites for 27 brain and human wellness phenotypes and identified eight metabolites to be causal for eight traits (11 relationships). Low mannose level was causal to bipolar disorder and as dietary supplement it may provide therapeutic benefits. Low galactosylglycerol level was found causal to Parkinson’s Disease (PD). Our study expanded the knowledge of MQTL in central nervous system, provided insights into human wellness, and successfully demonstrates the utility of combined statistical approaches to inform interventions.

Abstract Enhanced DNA repair is an important mechanism of inherent and acquired resistance to DNA targeted therapies, including poly ADP ribose polymerase inhibition. Spleen associated tyrosine kinase (Syk) is a non-receptor tyrosine kinase known to regulate immune cell function, cell adhesion, and vascular development. Here, we report that Syk can be expressed in high grade serous ovarian cancer and triple negative breast cancers and promotes DNA double strand break resection, homologous recombination (HR) and therapeutic resistance. We found that Syk is activated by ATM following DNA damage and is recruited to DNA double strand breaks by NBS1. Once at the break site, Syk phosphorylates CtIP, a key mediator of resection and HR, at Thr-847 to promote repair activity, specifically in Syk expressing cancer cells. Syk inhibition or genetic deletion abolished CtIP Thr-847 phosphorylation and overcame the resistant phenotype. Collectively, our findings suggest that Syk drives therapeutic resistance by promoting DNA resection and HR through a novel ATM-Syk-CtIP pathway, and that Syk is a new tumor-specific target to sensitize Syk-expressing tumors to PARPi and other DNA targeted therapy.

Abstract Introduction Cigarette smoking is highly prevalent among Asian American immigrant subgroups. Previously, Asian-language telephone Quitline services were only available in California. In 2012, the Centers for Disease Control and Prevention (CDC) funded the national Asian Smokers’ Quitline (ASQ) to expand Asian-language Quitline services nationally. However, there are relatively few calls to the ASQ from outside California. Aims and Methods This pilot study assessed the feasibility of two proactive outreach interventions to connect Vietnamese-speaking participants who smoke to the ASQ. Both interventions, (1) proactive telephone outreach with a counselor trained in motivational interviewing (PRO-MI) and (2) proactive telephone outreach with interactive voice response (PRO-IVR), were adapted to be culturally and linguistically appropriate for Vietnamese-speaking participants. Participants were randomly assigned 2:1 to PRO-IVR versus PRO-MI. Assessments were conducted at baseline and 3 months post-enrollment. Feasibility indicators were the recruitment rate and initiation of ASQ treatment. Results Using the HealthPartners electronic health record, a large health system in Minnesota, we identified approximately 343 potentially eligible Vietnamese participants who were mailed invitation letters and baseline surveys with telephone follow-up. We enrolled 86 eligible participants (25% recruitment rate). In the PRO-IVR group 7/58 participants were directly transferred to the ASQ (12% initiation rate) and in the PRO-MI group 8/28 participants were warm transferred to the ASQ (29% initiation rate). Conclusions This pilot study demonstrates the feasibility of our recruitment methods and of implementing proactive outreach interventions to promote the initiation of smoking cessation treatment with the ASQ. Implications This pilot study contributes novel data on the uptake of Asian Smokers’ Quitline (ASQ) services among Vietnamese-speaking people who smoke (PWS) with two proactive outreach interventions: (1) proactive telephone outreach with a counselor trained in motivational interviewing (PRO-MI) and (2) proactive telephone outreach with interactive voice response (PRO-IVR). We found that it is feasible to implement these proactive outreach interventions to promote the initiation of ASQ cessation treatment among Vietnamese-language speaking PWS. Future large trials are needed to rigorously compare PRO-MI and PRO-IVR and conduct budget impact analyses to understand the most efficient strategies for incorporation into health system settings.

Abstract An important aspect to determine the efficacy of a targeted macromolecule in treating brain tumors is penetration and activity in tumor across a heterogeneously intact blood-brain barrier. In this study, novel epidermal growth factor receptor (EGFR)-targeted antibody drug conjugates (ADCs) were constructed with a focus on cytotoxicity in glioblastoma (GBM) with an EGFR heterogeneous cell population. Initially, the cytotoxicity of free payloads with multiple mechanisms of cell kill was assessed. These included tesirine (TS, induces DNA cross-links), deruxtecan (Dxd) and SN38 (inhibit topoisomerase I), and an auristatin (MMAE) and maytansinoid (DM1) (inhibit microtubule polymerization). Across four GBM PDXs with varied EGFR expression (GBM6, 39 and 108- EGFRviii amplified; GBM10 - non-amplified), free TS and MMAE were consistently potent with EC50 values ranging from 0.50-45.9 pM and 7.9-229.1 pM, respectively. In contrast, the other free toxins were less potent; EC50 values: Dxd, 0.21-13.1 nM; SN38, 0.87-5.6 nM; DM1, 2.1-19.9 nM. Based on these results, the 40H3 EGFR-specific IgG was used to construct ADCs with TS and MMAE. 40H3-TS had a drug:antibody ratio (DAR) of 2.5 and was potently cytotoxic in GBM6, GBM39 and GBM108, while minimal cytotoxicity was observed in GBM10 or normal astrocyte SVG-A cells. 40H3-MMAE had a DAR of 3 and was similarly effective in GBM6 and GBM39 but less potent in GBM108, GBM10, and SVG-A. Bystander cytotoxicity was evaluated U87 cells expressing eGFP/fLuc2 (U87eGFP/fluc2) or EGFRviii (U87EGFRviii). Using live-cell imaging, U87EGFRviii cells treated with 40H3-TS or 40H3-MMAE had significantly reduced cell confluence relative to control. The same drug treatments in U87eGFP/fLuc2 cells had no effect on growth/confluence. However, in a 1:1 mixed culture, overall confluence was reduced from 89% in control to 35% and 32% after 40H3-TS (p<0.0001) or 40H3-MMAE (p<0.0001) treatment, respectively. This bystander killing of U87eGFP/fLuc2 cells was indicated by a reduction in confluence of green-fluorescent cells from 50% in control versus 29% with 40H3-TS (p<0.0001) and 26% with 40H3-MMAE (p<0.0001) treatment. In GBM39 orthotopic tumors, a single infusion of 10 or 20 µg 40H3-TS via convection enhanced delivery (CED) reduced the bioluminescence signal 7 days post treatment by ~10-fold (p=0.03) as compared to 40H3 control. However, 50% and 80% mortality was observed within a week of infusing 10 and 20 µg 40H3-TS, respectively. Neurotoxicity was associated with neuron loss in treated hemisphere as determined by NeuN staining. In summary, these data highlight the potential for novel EGFR-targeted ADCs to provide potent direct and bystander cytotoxicity to GBM cells. However, further selection and optimization of the conjugated toxins will be required to balance potency and bystander killing with toxicity for EGFR-targeted ADCs. Citation Format: Sonia Jain, Eric Chun Ho, Kendra A. Porath, Antonella Antignani, David J. FitzGerald, Jann N. Sarkaria. Bystander effects of EGFR-targeting 40H3 antibody-drug conjugates in glioblastoma with heterogeneous EGFR expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 556.