Publications

Many cancers are refractory to immune checkpoint therapy (ICT), but the causes of ICT resistance remain unknown. Despite low mutational burden, hepatocellular carcinoma (HCC) responds to PD-1 blockade, but prostate cancer (PCa) does not. RNA-seq analysis revealed that, unlike HCC, PCa cells poorly express MHC-I molecules and components of the MHC-I antigen processing and presentation machinery. We found that treatment of PCa cells and other tumor types with platin-based drugs, especially low dose Oxaliplatin, led to a pronounced upregulation of MHC-I molecules and their antigen generating and loading machinery. Most importantly, Oxaliplatin synergistically potentiated the effect of exogenous IFNγ; a conclusion based on two cumulative observations. First, ATAC-seq analyses revealed that Oxaliplatin activates MHC machinery through different pathways compared to well-known IFNγ signaling. Second, Oxaliplatin upregulates IFNγR2 expression in cancer cells. Induction of IFNγR2, which was needed for Oxaliplatin-potentiation of ICT-induced tumor rejection in vivo, depended on NF-κB signaling. Induction of IFNγR2, which was needed for Oxaliplatin-potentiation of ICT-induced tumor rejection in vivo, depended on NF-κB signaling. Moreover, we found that Oxaliplatin activates histone acetyltransferases (HATs) which alter chromatin structure of genes encoding MHC-I complex components, thereby enabling recruitment of a diverse array of activating transcription factors.Our data indicates that combining ICT with an appropriate low dose platinoid chemotherapeutic agent is useful in reinvigorating the immune response to tumors that have escaped immune destruction due to MHC-I downregulation and do not respond to single agent therapy.Citation Format: Ingmar Niels Bastian, Weihua Li, Qui Phung, Kathleen Fisch, Jennie Lill, Michael Karin, Shabnam Shalapour. Platinoid-induced MHCI antigen presentation enables checkpoint inhibitor responsiveness [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 2247.

The transcriptional activity of c-Jun is augmented through phosphorylation at two sites by a c-Jun amino-terminal kinase (JNK). All cells express two distinct JNK activities, 46 and 55 kD in size. It is not clear which of them is the more important c-Jun kinase and how they specifically recognize c-Jun. The 46-kD form of JNK was identified as a new member of the MAP kinase group of signal-transducing enzymes, JNK1. Here, we report the molecular cloning of the 55-kD form of JNK, JNK2, which exhibits 83% identity and similar regulation to JNK1. Despite this close similarity, the two JNKs differ greatly in their ability to interact with c-Jun. JNK2 binds c-Jun approximately 25 times more efficiently than JNK1, and as a result has a lower Km toward c-Jun than JNK1. The structural basis for this difference was investigated and traced to a small beta-strand-like region near the catalytic pocket of the enzyme. Modeling suggests that this region is solvent exposed and therefore is likely to serve as a docking site that increases the effective concentration of c-Jun near JNK2. These results explain how two closely related MAP kinases can differ in their ability to recognize specific substrates and thereby elicit different biological responses.

Although activation of Toll-like receptor 4 (TLR4)-positive cells is essential for eliminating Gram-negative bacteria, overactivation of these cells by the TLR4 ligand LPS initiates a systemic inflammatory reaction and shock. Here we demonstrate that SPRET/Ei mice, derived from Mus spretus, exhibit a dominant resistance against LPS-induced lethality. This resistance is mediated by bone marrow-derived cells. Macrophages from these mice exhibit normal signaling and gene expression responses that depend on the myeloid differentiation factor 88 adaptor protein, but they are impaired in IFN-beta production. The defect appears to be specific for IFN-beta, although the SPRET/Ei IFN-beta promoter is normal. In vivo IFN-beta induction by LPS or influenza virus is very low in SPRET/Ei mice, but IFN-beta-treatment restores the sensitivity to LPS, and IFN type 1 receptor-deficient mice are also resistant to LPS. Because of the defective induction of IFN-beta, these mice are completely resistant to Listeria monocytogenes and highly sensitive to Leishmania major infection. Stimulation of SPRET/Ei macrophages leads to rapid down-regulation of IFN type 1 receptor mRNA expression, which is reflected in poor induction of IFN-beta-dependent genes. This finding indicates that the resistance of SPRET/Ei mice to LPS is due to disruption of a positive-feedback loop that amplifies IFN-beta production. In contrast to TLR4-deficient mice, SPRET/Ei mice resist both LPS and sepsis induced with Klebsiella pneumoniae.

544 Project GRAD is a randomized, controlled trial to determine the efficacy of a cognitive/behavioral intervention to increase or maintain physical activity among young adults. 338 undergraduate seniors were randomly assigned to either a behavioral intervention or to a control group. An objective measure of physical activity, the Tritrac Accelerometer was worn by a subsample of students (n=32 control, n=38 intervention; 57% female, 40% ethnic minority) approximately one year following the intervention. The accelerometer is a motion sensor that assesses movement in three planes, (vertical, horizontal, and side to side). Participants wore the tritrac for at least 8 hours/day for 7 consecutive days. The purpose of this study is to examine the intervention effects on this objective measure of physical activity, specifically minutes spent in light, moderate, and vigorous physical activity per week. The number of 10 and 20 minute boats of moderate and vigorous physical activity were calculated. The cutoffs used to define intensity were derived in another study. Groups were compared using independent t-tests separately by sex. Men in the intervention group completed more bouts of moderate physical activity(both 10 and 20 minute) than men in the control group (2.8 vs 0.8, p<.03 and 1.7 vs 0.3, p<.04 bouts, respectively). There were no significant differences for vigorous physical activity and no differences for women. There were no significant differences between intervention and control groups for the number of minutes spent in physical activity of any intensity. For women, the average min/wk spent in moderate and vigorous physical activity was 128.2 (87.7) and 18.5 (39.0), respectively, for control and 146.4 (67.3) and 31.3 (82.5), respectively, for intervention groups. For men, the average minutes spent in moderate or vigorous activity was 171.2 (93.0) and 23.4 (34.6), respectively, for control and 211.0 (88.7) and 22.2 (31.2), respectively, for intervention groups. The intervention appeared to increase continuous bouts of PA in men, but the total minutes of physical activity in all groups assessed by an objective measure, were much lower than expected.

Overweight and obesity are established risk factors for insulin resistance in youth. A number of behavioral recommendations have been publicized with the goal of improving glycemic control. However, there is limited information about whether meeting these behavioral recommendations actually reduces insulin resistance. 92 youths 11 - 16 years with BMI ≥ 85% underwent oral glucose tolerance testing. HOMA-IR and AUCInsulin/AUCGlucose were calculated as measures of insulin resistance. Dietary and physical activity (PA) measures were performed. Assessments included whether or not participants met recommended levels of diet, PA and sedentary behaviors. 62% youths met criteria for insulin resistance. 82% (75/92) met at least one behavioral recommendation. Participants who met ≥ 1 dietary, sedentary, or PA recommendations had significantly reduced insulin resistance as compared with youth who did not. This relationship remained significant in multivariate modeling of insulin resistance adjusting for age, sex, and BMI. Even relatively minor behavior change may reduce insulin resistance in youth at risk for diabetes. Our findings support the relevance of current behavioral interventions for glycemic control. Clinical Trials #NCT00412165 .

In the age of digital healthcare, passively collected physical activity profiles from wearable sensors are a preeminent tool for evaluating health outcomes. In order to fully leverage the vast amounts of data collected through wearable accelerometers, we propose to use quantile functional regression to model activity profiles as distributional outcomes through quantile responses, which can be used to evaluate activity level differences across covariates based on any desired distributional summary. Our proposed framework addresses two key problems not handled in existing distributional regression literature. First, we use spline mixed model formulations in the basis space to model nonparametric effects of continuous predictors on the distributional response. Second, we address the underlying missingness problem that is common in these types of wearable data but typically not addressed. We show that the missingness can induce bias in the subject-specific distributional summaries that leads to biased distributional regression estimates and even bias the frequently used scalar summary measures, and introduce a nonparametric function-on-function modeling approach that adjusts for each subject's missingness profile to address this problem. We evaluate our nonparametric modeling and missing data adjustment using simulation studies based on realistically simulated activity profiles and use it to gain insights into adolescent activity profiles from the Teen Environment and Neighborhood study.