Citations

Abstract Cytotoxic CD8+ T cells play a key role in response to anti-PD-1/PD-L1 immune checkpoint inhibitors (ICI) therapy. However, the exact effector molecules that are regulated by PD-1 signals in cytotoxic CD8+ T cells have not been completely defined. Lack of this knowledge is a crucial problem in addressing how to overcome the low clinical response rate to ICI therapy. When exploring why certain patients not responding to ICI therapy, we found non-responders did not have an elevated NKG7 expression in CD8+ T cells as responders to ICI therapy. The difference in NKG7 expression in CD8+ T cells between non-responders and responders to anti-PD-1 therapy prompted us to investigate the potential role of PD-1 signaling in regulating NKG7 expression. To that end, we generated a CD8+ T cell-specific Pdcd1 conditional knockout mice (CD8 E8ICre-Pdcd1fl/fl, also known as CD8-PD-1 cKO) where Pdcd1 is deleted after thymic selection of single positive CD8+ T cells. We observed a delayed tumor growth and prolonged survival in CD8-PD-1 cKO mice compared to control mice after B16-OVA melanoma tumor challenge. On Day 12, when the CD8-PD-1 cKO mice demonstrated their ability to control tumor growth, we conducted single cell RNA sequencing on isolated tumor infiltrating CD8+ T cells, revealing a significant increase of Nkg7 expression in effector CD8+ T cells in the Pdcd1 deficient CD8+ T cells compared to the control wild type T cells. Pdcd1-deficient effector CD8+ T cells also had increased expression of genes linked to NFAT/Calcineurin signaling pathway including Nfatc1, S100a4, Tbet and Tox, suggesting Nkg7 could be regulated by Pdcd1 via the NFAT pathway. To determine the impact of increased NKG7 expression in CD8+ T cells, we used OVA protein as a surrogate tumor antigen in vaccination. We found a complete B16-OVA tumor rejection in CD8-PD-1 cKO mice compared to control mice when tumor cells were injected on day 7 after vaccination with OVA protein and poly (I:C) (as an adjuvant), but only a partial rejection on day 21. The CD8-PD-1 cKO mice that were tumor-free for 30-40 days rejected 2nd tumor challenge with B16-OVA tumors. This long-term protection is tumor antigen (OVA) specific because these mice did not reject B16F10 tumor cells that do not express OVA antigen. We also found effector memory CD8+ T cells with high cytotoxicity increased in the spleen of CD8-PD-1 cKO mice after OVA antigen immunization compared to control. In conclusion, we found NKG7 is one of the effector molecules in cytotoxic CD8+ T cells, which can be regulated by PD-1 signals through NFAT signaling. Targeting the PD-1-NFAT pathway may be a new option to overcome low responses of T cells to ICI therapy in treatment of refractory cancer. Citation Format: Zhiming Mao, Joanina Gicobi, Jacob Hirdler, Xin Liu, Michelle Hsu, Emilia Dellacecca, Wenjing Zhang, Fabrice Lucien-Matteoni, Hai dong. PD-1 signals regulate NKG7 that is required for CD8+ T cells to sustain cytotoxicity and durable antitumor memory responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3979.

Abstract Background: Although targeting myeloid cells has become one of the next generation targets for cancer immunotherapy, there is a lack of therapeutic tools to specifically target these cells. Our group has developed a novel humanized PD-L1-targeting antibody, H1A, that induces PD-L1 degradation via blockade of PD-L1 and CMTM6, therefore limiting PD-L1 intrinsic signaling while also preventing interactions with PD-1. In the immune cell compartment, CMTM6 expression is restricted to myeloid cells, making these cells the primary target of H1A. Recently, we unexpectedly found that targeting intrinsic PD-L1 in myeloid cells via H1A resulted in increased release of CCL2 from myeloid cells. In this study, we examined the role of CCL2/CCR2 signaling in CD8 T cell function using human peripheral blood-derived immune cells and evaluated the therapeutic potential of H1A antibody using our humanized PD-L1/PD-1 mouse model. Methods: Human PBMCs derived from healthy donors were treated with H1A or Atezolizumab, a blocking PD-L1 antibody, followed by mass cytometry and flow cytometry to evaluate immune cell phenotype and functional states. PD-L1 expressing myeloid cells isolated from human PBMCs were treated with H1A or Atezolizumab and assessed for CCL2 secretion using multiplex immunoassays. CCL2 production and transcription were confirmed by flow cytometry and single-cell RNA-sequencing. CCR2 blockade was used on human PBMCs to evaluate the effects of CCL2/CCR2 signaling on T cell function alongside H1A treatment. Finally, in vivo antitumor activity of H1A and Atezolizumab were compared in two humanized PD-L1 tumor models. Results: H1A reduced the frequency of regulatory T cells and increased effector T cells, in whole PBMCs upon global T cell activation with anti-CD3/CD28. H1A enhanced the secretion and production of CCL2 from myeloid cells, which was confirmed at a transcript level. CCR2 blockade diminished CD8 T cells’ ability to differentiate into effector cells in H1A treated PBMCs. H1A demonstrated comparable therapeutic effects with Atezolizumab in treatment of immunogenic and ICI-responsive mouse tumor MC38, which is CD8 T cell-dependent, but showed superior therapeutic effects in treatment of ICI-insensitive mouse tumor E0771 compared to Atezolizumab. Both treatments elicited durable memory specific immune responses upon E0771 tumor rechallenge. Conclusion: H1A demonstrated a superior antitumor activity compared to Atezolizumab in our preclinical models via a new mechanism by which H1A caused degradation of intrinsic PD-L1 in myeloid cells. This causes more release of CCL2 to improve T cell function via CCR2 upon T cell activation. Thus, H1A is emerging as a new immunotherapy tool to target PD-L1/CMTM6 in myeloid cells for treatment of cancers that are refractory to current immune checkpoint inhibitor therapy. Citation Format: Michelle Alexandria Hsu, Xin Liu, Ying Li, Whitney Barham, Kevin Pavelko, Jake Hirdler, Fabrice Lucien, Haidong Dong. Targeting PD-L1/CMTM6 in myeloid cells results in elevated release of CCL2 to improve CD8 T cell-mediated antitumor response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2664.

HLA‐DQA1*05:101 differs from HLA‐DQA1*05:01:01:02 by one nucleotide substitution at codon 221 (CGT>TGT) in exon 4.

Abstract Rheumatoid arthritis (RA) causes immunological and metabolic imbalances in tissue, exacerbating inflammation in affected joints. Changes in immunological and metabolic tissue homeostasis at different stages of RA are not well understood. Herein, the changes in the immunological and metabolic profiles in different stages in collagen induced arthritis (CIA), namely, early, intermediate, and late stage is examined. Moreover, the efficacy of the inverse‐vaccine, paKG(PFK15+bc2) microparticle, to restore tissue homeostasis at different stages is also investigated. Immunological analyses of inverse‐vaccine‐treated group revealed a significant decrease in the activation of pro‐inflammatory immune cells and remarkable increase in regulatory T‐cell populations in the intermediate and late stages compared to no treatment. Also, glycolysis in the spleen is normalized in the late stages of CIA in inverse‐vaccine‐treated mice, which is similar to no‐disease tissues. Metabolomics analyses revealed that metabolites UDP‐glucuronic acid and L‐Glutathione oxidized are significantly altered between treatment groups, and thus might provide new druggable targets for RA treatment. Flux metabolic modeling identified amino acid and carnitine pathways as the central pathways affected in arthritic tissue with CIA progression. Overall, this study shows that the inverse‐vaccines initiate early re‐establishment of homeostasis, which persists through the disease span.

ImportanceRedirection of care refers to withdrawal, withholding, or limiting escalation of treatment. Whether maternal social determinants of health are associated with redirection of care discussions merits understanding.ObjectiveTo examine associations between maternal social determinants of health and redirection of care discussions for infants born extremely preterm.Design, Setting, and ParticipantsThis is a retrospective analysis of a prospective cohort of infants born at less than 29 weeks’ gestation between April 2011 and December 2020 at 19 National Institute of Child Health and Human Development Neonatal Research Network centers in the US. Follow-up occurred between January 2013 and October 2023. Included infants received active treatment at birth and had mothers who identified as Black or White. Race was limited to Black and White based on service disparities between these groups and limited sample size for other races. Maternal social determinant of health exposures were education level (high school nongraduate or graduate), insurance type (public/none or private), race (Black or White), and ethnicity (Hispanic or non-Hispanic).Main Outcomes and MeasuresThe primary outcome was documented discussion about redirection of infant care. Secondary outcomes included subsequent redirection of care occurrence and, for those born at less than 27 weeks’ gestation, death and neurodevelopmental impairment at 22 to 26 months’ corrected age.ResultsOf the 15 629 infants (mean [SD] gestational age, 26 [2] weeks; 7961 [51%] male) from 13 643 mothers, 2324 (15%) had documented redirection of care discussions. In unadjusted comparisons, there was no significant difference in the percentage of infants with redirection of care discussions by race (Black, 1004/6793 [15%]; White, 1320/8836 [15%]) or ethnicity (Hispanic, 291/2105 [14%]; non-Hispanic, 2020/13 408 [15%]). However, after controlling for maternal and neonatal factors, infants whose mothers identified as Black or as Hispanic were less likely to have documented redirection of care discussions than infants whose mothers identified as White (Black vs White adjusted odds ratio [aOR], 0.84; 95% CI, 0.75-0.96) or as non-Hispanic (Hispanic vs non-Hispanic aOR, 0.72; 95% CI, 0.60-0.87). Redirection of care discussion occurrence did not differ by maternal education level or insurance type.Conclusions and RelevanceFor infants born extremely preterm, redirection of care discussions occurred less often for Black and Hispanic infants than for White and non-Hispanic infants. It is important to explore the possible reasons underlying these differences.

AbstractBackgroundBreast cancer patients experienced heightened anxiety during the pandemic. Also, modifications to clinical trial activities allowing for virtual platforms, local assessments, and greater flexibility were introduced to facilitate participation. We sought to evaluate the association between pandemic‐related anxiety and willingness to participate in trials and how pandemic‐era modifications to trial activities affect the decision to participate.MethodsWe conducted an online survey from August to September, 2021 of patients with breast cancer assessing pandemic‐related anxiety; clinical trials knowledge and attitudes; willingness to participate during and before the pandemic; and how each modification affects the decision to participate. Fisher's exact tests evaluated differences in proportions and two‐sample t‐tests evaluated differences in means. The association of pandemic‐related anxiety with a decline in willingness to participate during compared to prior to the pandemic was modeled using logistic regression.ResultsAmong 385 respondents who completed the survey, 81% reported moderate–severe pandemic‐related anxiety. Mean willingness to participate in a trial was lower during the pandemic than prior [2.97 (SD 1.17) vs. 3.10 (SD 1.09), (p < 0.001)]. Severe anxiety was associated with higher odds of diminished willingness to participate during the pandemic compared to prior (OR 5.07). Each of the modifications, with the exception of opting out of research‐only blood tests, were endorsed by >50% of respondents as strategies that would increase their likelihood of deciding to participate.ConclusionsWhile pandemic‐related anxiety was associated with diminished willingness to participate in trials, the leading reasons for reluctance to consider trial participation were unrelated to the pandemic but included worries about not getting the best treatment, side effects, and delaying care. Patients view trial modifications favorably, supporting continuation of these modifications, as endorsed by the National Cancer Institute and others.

Abstract Defining prognostic variables in T-lymphoblastic lymphoma (T-LL) remains a challenge. AALL1231 was a Children’s Oncology Group phase 3 clinical trial for newly diagnosed patients with T acute lymphoblastic leukemia or T-LL, randomizing children and young adults to a modified augmented Berlin-Frankfurt-Münster backbone to receive standard therapy (arm A) or with addition of bortezomib (arm B). Optional bone marrow samples to assess minimal residual disease (MRD) at the end of induction (EOI) were collected in T-LL analyzed to assess the correlation of MRD at the EOI to event-free survival (EFS). Eighty-six (41%) of the 209 patients with T-LL accrued to this trial submitted samples for MRD assessment. Patients with MRD &lt;0.1% (n = 75) at EOI had a superior 4-year EFS vs those with MRD ≥0.1% (n = 11) (89.0% ± 4.4% vs 63.6% ± 17.2%; P = .025). Overall survival did not significantly differ between the 2 groups. Cox regression for EFS using arm A as a reference demonstrated that MRD EOI ≥0.1% was associated with a greater risk of inferior outcome (hazard ratio, 3.73; 95% confidence interval, 1.12-12.40; P = .032), which was independent of treatment arm assignment. Consideration to incorporate MRD at EOI into future trials will help establish its value in defining risk groups. CT# NCT02112916.