Citations

Abstract Senescent cells drive age-related tissue dysfunction partially via the induction of a chronic senescence-associated secretory phenotype (SASP). Mitochondria are major regulators of the SASP; however, the underlying mechanisms have not been elucidated. Mitochondria also control apoptosis, a cell fate generally perceived as distinct from cellular senescence, which is apoptosis resistant. Here, we show that mitochondrial outer membrane permeability (MOMP) occurring in a small subset of mitochondria is a feature of cellular senescence. This process, called minority MOMP (miMOMP), depends on the formation of BAX and BAK macropores and results in release of mitochondrial DNA (mtDNA) into the cytosol, which in turn activates the cGAS/STING pathway, a major regulator of the SASP. Importantly, we found that inhibition of MOMP in vivo decreases inflammatory markers and improves healthspan parameters in aged mice. Our results propose the novel concept that apoptosis and senescence are regulated by similar mitochondrial-dependent mechanisms, and that sub-lethal mitochondrial apoptotic stress is a major driver of the SASP. We also provide proof-of-concept that inhibition of miMOMP may be a new therapeutic avenue to improve healthspan.

Abstract Background: Engineered toxin bodies (ETBs) are composed of a de-immunized Shiga-like Toxin A subunit genetically fused to an antibody-like binding domain. ETBs can force receptor internalization, induce potent cell-kill via enzymatic and permanent inactivation of ribosomes, and may not be subject to resistance mechanisms of other therapeutics. MT-5111 is a 55 kD ETB targeting HER2 in solid tumors that binds to an epitope distinct from trastuzumab and pertuzumab, offering potential combination strategies with other HER2-targeting agents. MT-5111 may demonstrate efficacy in patients (pts) resistant to other HER2-targeting agents, as its mechanism of action does not rely on inhibition of kinase signaling or cytoskeletal or DNA damage. Methods: The primary objective is to determine the maximum tolerated dose (MTD) of MT-5111 monotherapy in adult pts with advanced HER2+ solid tumors. Secondary objectives are pharmacokinetics (PK), efficacy, and immunogenicity. Using a modified 3+3 design, the dose-escalation part of the study enrolls pts with HER2+ tumors into 7 cohorts: 0.5, 1, 2, 3, 4.5, 6.75, and 10 µg/kg/dose. Three dose-expansion cohorts will follow for HER2+ breast cancer, gastro-esophageal cancer, and other HER2+ tumors. All pts receive MT-5111 weekly as 30-min IV infusions in each 21-day treatment (tx) cycle (C) until disease progression (PD), unacceptable toxicity, death, or withdrawn consent (NCT04029922). Results: Per data cut in June 2021, 21 pts (mean age 64 years, range 34-78; 38% male) in cohorts 1-6 with breast (n=7), biliary (n=6), gastric (n=3), pancreatic (n=2), lung (n=2), and colon (n=1) cancer were treated (Table 1). Pts had a median of 4 prior lines of systemic therapies (range, 1-8) and 2 prior lines of HER2-targeting treatments (range, 0-6). No Grade (G)4 or 5 tx-emergent (TE) adverse events (AEs) occurred. Tx-related AEs occurred in 11 (52%) pts; the most common was fatigue (n=7, 33%). One pt (4.5 µg/kg) had a possibly (per PI) related G3 serious AE (SAE) of dyspnea and hypoxia, but also lymphangitic carcinomatosis and H. influenzae infection. The other related SAE occurred in a pt (6.75 µg/kg) who had a G1 transient troponin increase without concomitant cardiac symptoms or ECG/ECHO changes. All other related AEs were ≤G2. There were no clinically significant changes in cardiac biomarkers (troponin, ECG, left ventricular ejection fraction) nor were there cases of capillary leak syndrome. Two pts (3 µg/kg and 4.5 µg/kg) had reversible G2 infusion-related reactions. Best response to date has been stable disease. AUClast data matched PK simulations based on non-human primate studies, and Cmax data at 6.75 µg/kg indicated that current in-human exposure was between the IC50 values of high and medium HER2-expressing cell lines (approximately 10-89 ng/mL). Thus, a dose of at least 10 µg/kg may be required to achieve effective exposure. To date, no dose-limiting toxicities have been observed and the 10 µg/kg/dose cohort is now accruing. Conclusions: MT-5111 was well tolerated with no clinically significant immuno- or cardiotoxicity. Dose escalation is ongoing and nearing levels expected to be required for efficacious exposure. Table 1.Metastatic HER2 status and MT-5111 treatment by cohortDose0.5 µg/kg1.0 µg/kg2.0 µg/kg3.0 µg/kg4.5 µg/kg6.75 µg/kgCohort123456Number of patients treated with MT-5111433335Metastatic HER2 2+ by IHC: ALL/BC1/11/11/01/10/04/0Metastatic HER2 3+ by IHC: ALL/BC3/12/02/12/13/01/1BC, breast cancer. Citation Format: Brian A. Van Tine, Monica Mita, Minal A. Barve, Erika P. Hamilton, Andrew J. Brenner, Frances Valdes, Daniel Ahn, Joleen Hubbard, Jason Starr, Angela Georgy, Joshua Pelham, Banmeet S. Anand, Thomas Strack, Andrés Machado Sandri, Zev A. Wainberg. Interim results of a phase 1 study of the novel immunotoxin MT-5111 in patients with HER2+tumors [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-13-45.

297 Background: MT-5111 is a 55 kD engineered toxin body (ETB) targeting HER2 in solid tumors that binds to an epitope distinct from trastuzumab and pertuzumab, offering potential combination strategies with other HER2-targeting agents. MT-5111 may demonstrate efficacy in patients (pts) resistant to other HER2-targeting agents, as its mechanism of action induces direct cell kill via enzymatic and permanent ribosome destruction and does not rely on inhibition of kinase signaling or cytoskeletal or DNA damage. Methods: This is a phase 1 study in adult pts with advanced HER2+ solid tumors. The dose-escalation portion (modified 3+3 design) enrolls pts into sequential cohorts followed by expansion cohorts for HER2+ breast cancer (BC), gastric or gastroesophageal junction adenocarcinoma (GEA), and other HER2+ tumors. MT-5111 is dosed weekly IV over 30 min in each 21-day treatment (tx) cycle until disease progression, unacceptable toxicity, death, or withdrawn consent. Results: As of Sep 2021 (contains preliminary data), 24 pts (mean age 64 yrs) were treated, 13 (54%) of whom had gastrointestinal (GI) tumors (6 biliary, 3 GEA, 2 pancreatic, 2 colo/rectal) (Table). Pts with GI tumors had a median of 3 prior systemic tx and 1 prior HER2-targeting tx. No Grade (G) 4/5 tx-emergent adverse events (AEs) occurred. Tx-related AEs occurred in 13 (54%) pts, most commonly fatigue (n=7, 29%). One pt with biliary cancer and concurrent lymphangitic carcinomatosis and H. influenzae infection (4.5 µg/kg) had a possibly related G3 serious AE (SAE) of dyspnea, which resolved 9 days later. Another related SAE occurred in a pt with GEA (6.75 µg/kg) who had a G1 transient troponin increase that resolved during hospitalization, with no clinical symptoms or ECG/ECHO changes; the pt withdrew from study before further dosing. All other related AEs were ≤G2. No other clinically significant changes in cardiac biomarkers (troponin, ECG, LVEF) or cases of capillary leak syndrome occurred. Two pts (3 and 4.5 µg/kg) had reversible G2 infusion-related reactions. Best response to date has been stable disease. AUClast data matched PK simulations based on non-human primate studies. Cmax data at 10 µg/kg indicate that current in-pt exposure was between IC50 values of high and medium HER2-expressing cell lines (approx 10-89 ng/mL). Thus, at least 10 µg/kg may be required to achieve effective exposure. No dose-limiting toxicities have been observed. The 10 µg/kg cohort is now accruing. Following this cohort, an expansion cohort for pts with BC will open. Conclusions: MT-5111 was well tolerated with no clinically significant immuno/cardiotoxicity. Dose escalation is ongoing and is nearing levels expected to be required for efficacious exposure. Clinical trial information: NCT04029922. [Table: see text]

Abstract Objective To describe and demonstrate use of pediatric data collected by the All of Us Research Program. Materials and Methods All of Us participant physical measurements and electronic health record (EHR) data were analyzed including investigation of trends in childhood obesity and correlation with adult body mass index (BMI). Results We identified 19 729 participants with legacy pediatric EHR data including diagnoses, prescriptions, visits, procedures, and measurements gathered since 1980. We found an increase in pediatric obesity diagnosis over time that correlates with BMI measurements recorded in participants’ adult EHRs and those physical measurements taken at enrollment in the research program. Discussion We highlight the availability of retrospective pediatric EHR data for nearly 20 000 All of Us participants. These data are relevant to current issues such as the rise in pediatric obesity. Conclusion All of Us contains a rich resource of retrospective pediatric EHR data to accelerate pediatric research studies.

Objective Determination of possible sex differences in mechanisms promoting migraine progression and the contribution of prolactin and the prolactin long (PRLR-L) and short (PRLR-S) receptor isoforms. Background The majority of patients with chronic migraine and medication overuse headache are female. Prolactin is present at higher levels in women and increases migraine. Prolactin signaling at the PRLR-S selectively sensitizes nociceptors in female rodents, while expression of the PRLR-L is protective. Methods Medication overuse headache was modeled by repeated sumatriptan administration in male and female mice. Periorbital and hindpaw cutaneous allodynia served as a surrogate of migraine-like pain. PRLR-L and PRLR-S isoforms were measured in the trigeminal ganglion with western blotting. Possible co-localization of PRLR with serotonin 5HT1B and 5HT1D receptors was determined with RNAscope. Cabergoline, a dopamine receptor agonist that inhibits circulating prolactin, was co-administered with sumatriptan. Nasal administration of CRISPR/Cas9 plasmid was used to edit expression of both PRLR isoforms. Results PRLR was co-localized with 5HT1B or 5HT1D receptors in the ophthalmic region of female trigeminal ganglion. A single injection of sumatriptan increased serum PRL levels in female mice. Repeated sumatriptan promoted cutaneous allodynia in both sexes but down-regulated trigeminal ganglion PRLR-L, without altering PRLR-S, only in females. Co-administration of sumatriptan with cabergoline prevented allodynia and down-regulation of PRLR-L only in females. CRISPR/Cas9 editing of both PRLR isoforms in the trigeminal ganglion prevented sumatriptan-induced periorbital allodynia in females. Interpretation We identified a sexually dimorphic mechanism of migraine chronification that involves down-regulation of PRLR-L and increased signaling of circulating prolactin at PRLR-S. These studies reveal a previously unrecognized neuroendocrine mechanism linking the hypothalamus to nociceptor sensitization that increases the risk of migraine pain in females and suggest opportunities for novel sex-specific therapies including gene editing through nasal delivery of CRISPR/Cas9 constructs.

Abstract Quantitative volumetric brain MRI measurement is important in research applications, but translating it into patient care is challenging. We explore the incorporation of clinical automated quantitative MRI measurements in statistical models predicting outcomes of surgery for temporal lobe epilepsy. Four hundred and thirty-five patients with drug-resistant epilepsy who underwent temporal lobe surgery at Cleveland Clinic, Mayo Clinic and University of Campinas were studied. We obtained volumetric measurements from the pre-operative T1-weighted MRI using NeuroQuant, a Food and Drug Administration approved software package. We created sets of statistical models to predict the probability of complete seizure-freedom or an Engel score of I at the last follow-up. The cohort was randomly split into training and testing sets, with a ratio of 7:3. Model discrimination was assessed using the concordance statistic (C-statistic). We compared four sets of models and selected the one with the highest concordance index. Volumetric differences in pre-surgical MRI located predominantly in the frontocentral and temporal regions were associated with poorer outcomes. The addition of volumetric measurements to the model with clinical variables alone increased the model’s C-statistic from 0.58 to 0.70 (right-sided surgery) and from 0.61 to 0.66 (left-sided surgery) for complete seizure freedom and from 0.62 to 0.67 (right-sided surgery) and from 0.68 to 0.73 (left-sided surgery) for an Engel I outcome score. 57% of patients with extra-temporal abnormalities were seizure-free at last follow-up, compared to 68% of those with no such abnormalities (P-value = 0.02). Adding quantitative MRI data increases the performance of a model developed to predict post-operative seizure outcomes. The distribution of the regions of interest included in the final model supports the notion that focal epilepsies are network disorders and that subtle cortical volume loss outside the surgical site influences seizure outcome.

Abstract Background: Engineered toxin bodies (ETBs), composed of an engineered Shiga-like Toxin A subunit genetically fused to an antibody-binding domain, can force receptor internalization, induce potent cell-kill via enzymatic and permanent inactivation of ribosomes, and may not be subject to resistance mechanisms of other targeted agents. MT-5111, a de-immunized 55 kD ETB targeting HER2 in solid tumors, also binds to an epitope distinct from trastuzumab and pertuzumab, which may permit combination strategies with other HER2 targeting agents. Methods: The primary objective is to determine maximum tolerated dose (MTD) of MT-5111 monotherapy in adult patients (pts) with advanced HER2+ solid tumors. Secondary objectives are PK, efficacy, and immunogenicity. Using a modified 3+3 design, the dose-escalation part of the study includes the following 7 cohorts: 0.5, 1, 2, 3, 4.5, 6.75, and 10 µg/kg. Three dose-expansion cohorts will follow for HER2+ breast cancer, gastro-esophageal cancer, and any other HER2+ tumors. All pts will receive MT-5111 weekly as a 30-min IV infusion in each 21-d treatment (tx) cycle (C) until disease progression (PD), unacceptable toxicity, death, or withdrawn consent (NCT04029922). Results: As of the data cut in December 2020, 16 pts were treated; cancer types included breast (n=6), gastric (n=1), colon (n=1), gallbladder (n=5), and other solid tumors (n=3). Mean age was 64 years (range, 34-78); 37.5% were male. Pts received a median of 4 prior lines of systemic therapies (range, 1-8). No G4 or G5 TEAEs occurred. Six pts had 11 G3 TEAEs; the most common were increased AST and dyspnea (both n=2). Three pts had tx-emergent serious adverse events (abdominal distension [n=1]; dyspnea [n=2]). Tx-related TEAEs occurred in 8 (50%) pts; the most common was fatigue (n=5, 31.3%) and all were ≤ grade 2 in nature, except for one grade 3 event of dyspnea. No cardiac TEAEs, clinically significant changes in cardiac biomarkers (troponin, electrocardiogram, left ventricular ejection fraction), or cases of capillary leak syndrome were observed. Fifteen pts discontinued with PD; 1 pt in cohort 5 (4.5 µg/kg) is on tx with stable disease. To date, no DLTs have been observed and the MTD has not been reached. One pt in cohort 2 (1 µg/kg) had resolution of all hepatic lesions (sub-centimeter lesions pre-tx) at the end of C8; however, the pt came off study due to clinical progression at the end of C10. PK data for the first 5 cohorts matched simulations based on non-human primate studies. Conclusions: MT-5111 was well tolerated with no clinically significant cardiotoxicity. Continued dose escalations are ongoing. Citation Format: Zev A. Wainberg, Monica M. Mita, Minal A. Barve, Erika P. Hamilton, Andrew J. Brenner, Frances Valdes, Daniel Ahn, Joleen Hubbard, Jason Starr, Christine Burnett, Joshua Pelham, Eric T. Williams, Banmeet S. Anand, Thomas Strack, Andrés Machado Sandri, Brian A. Van Tine. Phase 1 study of the novel immunotoxin MT-5111 in patients with HER-2+tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT130.