Citations

Abstract OBJECTIVE: We sought to define the mechanisms by which purines regulate DNA repair and therapy response. METHODS: Phosphoproteomics was used to identify GTP-dependent (de)phosphorylation events after radiation (RT) and antibodies generated against novel sites. Animal models of glioblastoma (GBM) and normal tissues were used to assess DNA repair and treatment responses in vivo. RESULTS: Pharmacogenomic inhibition of GTP (but not ATP) synthesis sensitized GBM cells to RT by inhibiting the activity of non-homologous end joining, but not homologous recombination. We found a GTP-dependent RT-induced dephosphorylation event on Abl interactor 1 (Abi-1) serine 323 (S323) using phosphoproteomics. We generated a new antibody for p-Abi-1 (S323), validated its specificity, and confirmed that RT causes a GTP-dependent dephosphorylation of Abi-1 (S323). Knockout of Abi-1 slowed RT-induced double-strand break (DSB) repair, and this was rescued by re-expression of dephosphomimetic Abi-1 (S323A) but not phosphomimetic Abi-1 (S323D). Abi-1 canonically binds to G protein Rac1. Expression of constitutively active Rac1 promoted but dominant negative Rac1 blocked the dephosphorylation of Abi-1 (S323) and DSB repair. Knock-down or inhibition of protein phosphatase 5 reversed the GTP- and Rac1-mediated dephosphorylation of Abi-1 and DSB repair. In GBM PDX samples, p-Abi-1 (S323) levels negatively correlated with Rac1 activity and predicted favorable efficacy of genotoxic treatments. In orthotopic GBM mouse models, inhibiting Rac1 enhanced RT responses and suppressed Abi-1 (S323) dephosphorylation. Abi-1 knockout enhanced efficacy of genotoxic treatments and could be rescued by Abi-1 S323A (but not Abi-1 S323D) re-expression. This regulation is generalizable beyond brain cancer, as GTP supplementation promoted DNA repair and p-Abi1 (S323) dephosphorylation in non-malignant cells and protected mice from RT-mediated gastrointestinal injury and bleomycin-induced pulmonary fibrosis. CONCLUSION: The GTP-Rac1-PP5-Abi-1 signaling axis links metabolism and DNA repair. Disrupting this pathway can overcome cancer resistance to genotoxic therapy while augmenting it can mitigate genotoxic injury of normal tissues. Citation Format: Weihua Zhou, Zitong Zhao, Angelica Lin, John Yang, Jie Xu, Kari Wilder-Romans, Annabel Yang, Andrew J. Scott, Jing Li, Sumeet Solanki, Jennifer Speth, Natalie Walker, Ayesha U. Kothari, Yangyang Yao, Erik R. Peterson, Navyateja Korimerla, Christian K. Werner, Jessica Liang, Janna Jacobson, Sravya Palavalasa, Alexandra M Obrien, Ameer L Elaimy, Sean P. Ferris, Shuang G. Zhao, Jann N. Sarkaria, Balázs Győrffy, Shuqun Zhang, Wajd N. Al-Holou, Yoshie Umemura, Meredith A Morgan, Theodore S. Lawrence, Costas A. Lyssiotis, Marc Peters-Golden, Yatrik M. Shah, Daniel R. Wahl. GTP signaling links metabolism, DNA repair, and responses to genotoxic stress [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr A004.

AbstractIntroductionThis case describes passenger lymphocyte syndrome (PLS) generating human platelet antigen 1a (HPA‐1a) alloantibodies against the recipient's platelets after liver transplant. Given the rarity of PLS, especially in liver transplant with HPA‐1a alloantibodies, disease course and management options are poorly described.MethodsThe patient had cirrhosis secondary to nonalcoholic steatohepatitis complicated by hepatocellular carcinoma, encephalopathy, and severe ascites. The model for end‐stage liver disease (MELD) score was 15 at presentation. The patient developed hepatic artery thrombosis after an orthotopic liver transplant and was relisted for transplant with a MELD score of 40. The patient received a hepatitis C virus antibody positive, hepatitis C virus nucleic amplification test positive donor liver on postoperative day (POD) 7 after first transplant. On POD 7 after the second transplant, the patient developed profound thrombocytopenia refractory to platelet infusion. They were found to have serum antibody to HPA‐1a based upon serum platelet alloantibody testing. The donor was later found to be negative for HPA‐1a by genetic testing. However, the patient's native platelets were HPA‐1a positive. The patient was diagnosed with PLS.ResultsThe patient's treatment course included 57 units of platelets transfused, emergency splenectomy, rituximab, plasma exchange, intravenous immunoglobulin (IVIG), eltrombopag, romiplostim, and efgartigimod.DiscussionThe synergistic effect of efgartigimod with eltrombopag and romiplostim most likely resolved the patient's thrombocytopenia. This case represents a novel use of efgartigimod in the treatment of passenger lymphocyte syndrome following liver transplant.

Key Points In heme protein–mediated AKI (HP-AKI), a senescence phenotype promptly occurs, and increased expression of p16 Ink4a contributes to HP-AKI. Renal p16 Ink4a expression is induced by hemoglobin, myoglobin, and heme in vivo and in renal epithelial cells exposed to heme in vitro . Impairing the binding or degradation of heme by hemopexin deficiency or heme oxygenase-1 deficiency, respectively, further upregulates p16 Ink4a . Background Understanding the pathogenetic basis for AKI involves the study of ischemic and nephrotoxic models of AKI, the latter including heme protein–mediated AKI (HP-AKI). Recently, interest has grown regarding the role of senescence as a mechanism of kidney injury, including AKI. We examined whether senescence occurs in HP-AKI and potential inducers of and the role of a key driver of senescence, namely, p16 Ink4a , in HP-AKI. Methods The long-established murine glycerol model of HP-AKI was used, and indices of senescence were examined. To evaluate the interaction of heme and p16 Ink4a expression, murine models of genetic deficiency of hemopexin ( HPX ) and heme oxygenase-1 ( HO-1 ) were used. To determine the involvement of p16 Ink4a in HP-AKI, the population of p16 Ink4a -expressing cells was reduced using the INK-ATTAC model. Results Using multiple indices, a senescence phenotype appears in the kidney within hours after the induction of HP-AKI. This phenotype includes significant upregulation of p16 Ink4a . p16 Ink4a is upregulated in the kidney after the individual administration of myoglobin, hemoglobin, and heme, as well as in renal epithelial cells exposed to heme in vitro . Genetic deficiencies of HPX and HO-1 , which, independently, are expected to increase heme content in the kidney, exaggerate induction of p16 Ink4a in the kidney and exacerbate HP-AKI, the latter shown in the present studies involving HPX −/− mice and in previous studies involving HO-1 −/− mice. Finally, reduction in the population of p16 Ink4a -expressing cells in the kidney improves renal function in HP-AKI even within 24 hours. Conclusions The pathogenesis of HP-AKI involves senescence and the induction of p16 Ink4a , the latter driven, in part, by hemoglobin, myoglobin, and heme.

AbstractProblemThe COVID‐19 pandemic has been shown to have a detrimental impact on the mental health of pregnant individuals, and chronic stress can alter the immune profile. However, the effects of the COVID‐19 pandemic on the immune system in pregnancy are still poorly understood. We aimed to evaluate the impact of pandemic exposure on the maternal immune profile in uncomplicated pregnancies.Method of studyWe collected blood and placenta samples from pregnant individuals exposed and unexposed to the pandemic to compare their immune and inflammatory profiles. We performed co‐culture with circulating maternal immune cells and endothelial cells to assess endothelial activation. Statistical analysis was performed using unpaired t‐test, Mann‐Whitney, or Fisher's exact test as appropriate.ResultsIn exposed individuals, we observed a decreased proportion of Th2 cells (p < .0001) and Treg/Th17 ratio (p < .05), as well as an increased Th1/Th2 ratio (p < .0001). Levels of IL‐1β (p < .01) and IL‐18 (p < .01) were increased in the circulation of exposed participants, whilst other mediators were significantly decreased (IFNγ, IL‐8, MCP‐1, amongst others). Furthermore, we observed increased production of ICAM, hallmark of endothelial activation, when we co‐cultured endothelial cells with immune cells from exposed individuals. Vaccination status impacted the cellular profile with increased proportions of Th1 and B cells in vaccinated participants.ConclusionOverall, we observed a pro‐inflammatory bias in the circulation of pregnant individuals exposed to the COVID‐19 pandemic, with otherwise uncomplicated pregnancies. Our work also supports an association between the increased risk of endothelial activation/hypertension and SARS‐CoV2 infection, which might be driven in part by exposure to the pandemic and associated stressors.

Abstract High-count monoclonal B-cell lymphocytosis (HCMBL) is a precursor condition to chronic lymphocytic leukemia (CLL). We have shown that among individuals with HCMBL, the CLL-International Prognostic Index (CLL-IPI) is prognostic for time-to-first therapy (TTFT). Little is known about the prognostic impact of somatically mutated genes among individuals with HCMBL. We sequenced DNA from 371 individuals with HCMBL using a targeted sequencing panel of 59 recurrently mutated genes in CLL to identify high-impact mutations. We compared the sequencing results with that of our treatment-naïve CLL cohort (N = 855) and used Cox regression to estimate hazard ratios and 95% confidence intervals (CIs) for associations with TTFT. The frequencies of any mutated genes were lower in HCMBL (52%) than CLL (70%). At 10 years, 37% of individuals with HCMBL with any mutated gene had progressed requiring treatment compared with 10% among individuals with HCMBL with no mutations; this led to 5.4-fold shorter TTFT (95% CI, 2.6-11.0) among HCMBL with any mutated gene vs none, independent of CLL-IPI. When considering individuals with low risk of progression according to CLL-IPI, those with HCMBL with any mutations had 4.3-fold shorter TTFT (95% CI, 1.6-11.8) vs those with none. Finally, when considering both CLL-IPI and any mutated gene status, we observed individuals with HCMBL who were high risk for both prognostic factors had worse prognosis than patients with low-risk CLL (ie, 5-year progression rate of 32% vs 21%, respectively). Among HCMBL, the frequency of somatically mutated genes at diagnosis is lower than that of CLL. Accounting for both the number of mutated genes and CLL-IPI can identify individuals with HCMBL with more aggressive clinical course.

INTRODUCTION: Modeling supporting recommendations for colonoscopy and stool-based colorectal cancer (CRC) screening tests assumes 100% sequential participant adherence. The impact of observed adherence on the long-term effectiveness of screening is unknown. We evaluated the effectiveness of a program of screening colonoscopy every 10 years vs annual high-sensitivity guaiac-based fecal occult blood testing (HSgFOBT) using observed sequential adherence data. METHODS: The MIcrosimulation SCreening ANalysis (MISCAN) model used observed sequential screening adherence, HSgFOBT positivity, and diagnostic colonoscopy adherence in HSgFOBT-positive individuals from the National Colonoscopy Study (single-screening colonoscopy vs ≥4 HSgFOBT sequential rounds). We compared CRC incidence and mortality over 15 years with no screening or 10 yearly screening colonoscopy vs annual HSgFOBT with 100% and differential observed adherence from the trial. RESULTS: Without screening, simulated incidence and mortality over 15 years were 20.9 (95% probability interval 15.8–26.9) and 6.9 (5.0–9.2) per 1,000 participants, respectively. In the case of 100% adherence, only screening colonoscopy was predicted to result in lower incidence; however, both tests lowered simulated mortality to a similar level (2.1 [1.6–2.9] for screening colonoscopy and 2.5 [1.8–3.4] for HSgFOBT). Observed adherence for screening colonoscopy (83.6%) was higher than observed sequential HSgFOBT adherence (73.1% first round; 49.1% by round 4), resulting in lower simulated incidence and mortality for screening colonoscopy (14.4 [10.8–18.5] and 2.9 [2.1–3.9], respectively) than HSgFOBT (20.8 [15.8–28.1] and 3.9 [2.9–5.4], respectively), despite a 91% adherence to diagnostic colonoscopy with FOBT positivity. The relative risk of CRC mortality for screening colonoscopy vs HSgFOBT was 0.75 (95% probability interval 0.68–0.80). Findings were similar in sensitivity analyses with alternative assumptions for repeat colonoscopy, test performance, risk, age, and projection horizon. DISCUSSION: Where sequential adherence to stool-based screening is suboptimal and colonoscopy is accessible and acceptable—as observed in the National Colonoscopy Study—offering screening colonoscopy can increase screening effectiveness.

PURPOSE Patients with biochemically recurrent prostate cancer (BRPC) after radical prostatectomy and a short PSA doubling time are at risk for distant metastases. Apalutamide, an androgen receptor antagonist, and abiraterone acetate plus prednisone (AAP) prolong survival in the metastatic setting. We evaluated whether intensification of androgen-deprivation therapy (ADT) improves outcomes in BRPC. PATIENTS AND METHODS PRESTO is a randomized phase III, open-label trial in patients with BRPC and PSA doubling time ≤9 months (ClinicalTrials.gov identifier: NCT03009981 ). Patients were randomly assigned 1:1:1 to receive a finite 52-week treatment course with ADT control, ADT + apalutamide, or ADT + apalutamide + AAP. The primary end point was PSA progression-free survival (PSA-PFS), defined as serum PSA >0.2 ng/mL after treatment completion. RESULTS Five hundred three patients were enrolled. The median PSA was 1.8 ng/mL (IQR, 1.0-3.6). At the first planned interim analysis, both experimental arms significantly prolonged PSA-PFS compared with the control arm (median, 24.9 months for ADT + apalutamide v 20.3 months for ADT; hazard ratio [HR], 0.52 [95% CI, 0.35 to 0.77]; P = .00047; median, 26.0 months for ADT + apalutamide + AAP v 20.0 months for ADT; HR, 0.48 [95% CI, 0.32 to 0.71]; P = .00008). Median time to testosterone recovery did not differ across treatment arms. The most common grade ≥3 adverse event was hypertension (7.5%, 7.4%, and 18% in ADT, ADT + apalutamide, and ADT + apalutamide + AAP arms, respectively). CONCLUSION Intensified AR blockade for a finite duration prolongs PSA-PFS with a manageable safety profile, without adversely affecting time to testosterone recovery. The addition of apalutamide to ADT should be considered in patients with high-risk BRPC.

AbstractDespite its high prevalence among dementias, Lewy body dementia (LBD) remains poorly understood with a limited, albeit growing, evidence base. The public‐health burden that LBD imposes is worsened by overlapping pathologies, which contribute to misdiagnosis, and lack of treatments. For this report, we gathered and analyzed public‐domain information on advocacy, funding, research outputs, and the therapeutic pipeline to identify gaps in each of these key elements. To further understand the current gaps, we also conducted interviews with leading experts in regulatory/governmental agencies, LBD advocacy, academic research, and biopharmaceutical research, as well as with funding sources. We identified wide gaps across the entire landscape, the most critical being in research. Many of the experts participated in a workshop to discuss the prioritization of research areas with a view to accelerating therapeutic development and improving patient care. This white paper outlines the opportunities for bridging the major LBD gaps and creates the framework for collaboration in that endeavor.Highlights A group representing academia, government, industry, and consulting expertise was convened to discuss current progress in Dementia with Lewy Body care and research. Consideration of expert opinion,natural language processing of the literature as well as publicly available data bases, and Delphi inspired discussion led to a proposed consensus document of priorities for the field.

PURPOSE Oncology advanced practice providers (APPs), including nurse practitioners, clinical nurse specialists, physician assistants, and clinical pharmacists, contribute significantly to quality cancer care. Understanding the research-related roles of APPs in the National Cancer Institute's (NCI) Community Oncology Research Program (NCORP) could lead to enhanced protocol development, trial conduct, and accrual. METHODS The 2022 NCORP Landscape Assessment Survey asked two questions about the utilization and roles of APPs in the NCORP. RESULTS A total of 271 practice groups completed the 2022 survey, with a response rate of 90%. Of the 259 nonpediatric exclusive practice groups analyzed in this study, 92% used APPs for clinical care activities and 73% used APPs for research activities. APPs most often provided clinical care for patients enrolled in trials (97%), followed by assistance with coordination (65%), presenting/explaining clinical trials (59%), screening patients (49%), ordering investigational drugs (37%), and consenting participants (24%). Some groups reported APPs as an enrolling investigator (18%) and/or participating in institutional oversight/selection of trials (15%). Only 5% of NCORP sites reported APPs as a site primary investigator for trials, and very few (3%) reported APPs participating in protocol development. CONCLUSION Practice groups report involving APPs in clinical research within the NCORP network; however, opportunities for growth exists. As team-based care has enhanced clinical practice in oncology, this same approach can be used to enhance successful research. Suggested strategies include supporting APP research-related time, recognition, and education. The findings of this survey and subsequent recommendations may be applied to all adult oncology practices that participate in clinical research.