Biology subjects

Gabrielson, K. L.

Publications and source records attributed to Gabrielson, K. L..

7 recordsLinked to original sources

bioRxiv2026

Spatial Regulation of CAR Signaling Enables Logic-Gated Activity

Chimeric antigen receptors (CARs) can induce T cells to kill cancer cells but also to kill normal cells that express the same antigens1. Designing CARs to recognize combinations of antigens, via Boolean logic, can simultaneously expand the scope of targetable antigens and make CAR T cells more specific to cancer2. For example, one antigen may be expressed on cancer cells and normal bone marrow cells, while a second antigen may be present on the same cancer cells but only in normal lungs. If recognition of both antigens is required for T cell activation, only the cancer cells will be killed. Creating such AND-gated CAR T cells has been challenging given the need to engineer non-natural signaling mechanisms that integrate two ligand binding events into a single T cell activation stimulus3-6. Here, we design a fundamentally new AND-gated receptor called Multi-ANtigen Triggered Immune Synapse (MANTIS), which leverages differences in extracellular receptor dimensions to regulate CAR signaling. MANTIS initially prevents CAR activity by steric blocking with a bulky extracellular domain. Upon engagement of the first antigen, MANTIS sheds this blocking domain, releasing a free CAR that can bind a second antigen and activate the T cell in an AND-gated manner. This work demonstrates how differences in extracellular receptor size can be leveraged to spatially regulate intracellular signaling pathways in response to antigen patterns, paving the way for new applications in synthetic biology and cell engineering. One sentence summaryDifferences in extracellular size can be leveraged to regulate CAR T cell activity for precise recognition of antigen patterns.

synthetic biology↗

bioRxiv2025

Guiding treatment response by spatiotemporal control of α-particle deposition in solid tumors: the case for 'affinity cocktails' of antibody-radioconjugates

Antibody-radioconjugates are leading the investigational targeted alpha-particle (-particle) therapies for the treatment of solid tumors that do not respond to approved therapies. Yet, there is still treatment failure in the clinic largely attributed to the heterogenous patterns of tumor irradiation by -particles. Although -particles are essentially impervious to resistance, attributed to the complex double-strand DNA breaks they cause while traversing cells, cells not being directly hit by -particles will likely not be killed. The diffusion-limited poor tumor penetration of high-affinity (strongly-binding) antibody-radioconjugates combined with -particles short-range in tissue (only 40-80m), let tumor regions far from vasculature inadequately irradiated, therefore, possibly escaping treatment. METHODSTo improve penetration of delivered activity within tumors, we engineered separate actinium-225 antibody-radioconjugates of variable affinities ( affinity cocktails) targeting the same marker on cancer cells, that were chosen based on their preferential irradiation of complementary regions of the same tumors. The cocktails comprise: (a) high-affinity antibody-radioconjugates (as the ones on clinical trials), which mostly deliver their cargo in tumor cells close to the vasculature, where the low(er)-affinity antibody-radioconjugates fail to deliver effective doses, due to their fast clearance; and (b) low(er)-affinity antibody-radioconjugates, that penetrate the deeper parts of tumors farther from the vasculature, where the high-affinity antibodies fail to reach. The efficacy of affinity cocktails was assessed in spheroids, that were employed as surrogates of tumor avascular regions, and on mice with subcutaneous xenografts of different cancer origin, expression levels and/or type of the targeted receptor: HER2 highly-expressing BT-474 breast cancer cells, HER2 moderately-expressing HEPG2 hepatoma cells, and/or HER1 low-expressing BxPC-3 pancreatic cancer cells. RESULTSAlthough the high-affinity antibody-radioconjugates were most lethal against cancer cells in monolayers, affinity cocktails were most effective in inhibiting spheroid growth, due to better collective spreading of the antibody-conjugates within the spheroids volume. On all mouse models, and for the same total injected activity, affinity cocktails resulted in the best tumor growth inhibition, even at lower tumor absorbed doses, compared to the high-affinity antibody-radioconjugates alone. CONCLUSIONSThis proof-of-concept study in -particle antibody-delivery to solid tumors demonstrates that separating the two key processes of diffusion and reaction/binding improves treatment efficacy. This generalizable approach may augment antibody-radioconjugates already in clinical trials.

bioengineering↗

bioRxiv2025

Actinium-225 dendrimer-radioconjugates combined with low-dose standard-of-care chemotherapy: site-independent treatment of triple negative breast cancer metastases

PURPOSEMetastatic triple negative breast cancer (mTNBC) is incurable largely due to the development of drug resistance, the lack of selective cell targeting, and/or limitations in tumor drug delivery that vary depending on the different (metastatic) tumor locations. METHODSThe potential of a single type of systemic, targeted alpha-particle therapy (TAT) was investigated for addressing the above challenges of TNBC tumors implanted at different anatomic sites in mice. Actinium-225 dendrimer-radioconjugates alone, and/or after pretreatment with low-dose standard-of-care cisplatin, were assessed in vitro and on immune-competent 4T1-Balb/c mouse models with tumors implanted intracranially, orthotopically or subcutaneously. RESULTSIn vitro, TATs efficacy was enhanced by cisplatin. In vivo, treatment was initiated well after tumors had grown (Vto = 39 {+/-} 14 mm3 in the intracranial model, and Vto=100mm3 in the orthotopic and subcutaneous models). Across all tumor implantation sites, a unified correlation was observed between animal mean survival and the dendrimer-delivered tumor absorbed doses, which were selectively increased by low-dose cisplatin pretreatment. Importantly, in all animal models, the mean survival following systemic treatment with both modalities was significantly longer vs. each modality alone and/or vs. no treatment, at injected doses that did not cause long-term (10-month) toxicities in tumor-free mice. CONCLUSIONSystemically-injected dendrimer-delivered TAT, combined with low-dose cisplatin pretreatment, can safely extend survival independent of mTNBC tumors anatomic site, potentially presenting a single type of therapy to simultaneously treat multi-site mTNBC.

bioengineering↗

bioRxiv2024

Glioblastoma Treatment by Systemic Actinium-225 alpha-particle Dendrimer-radioconjugates is Improved by Chemotherapy

RATIONALEThe poor prognosis of glioblastoma is largely due to drug resistance and tumor location that, together, make it difficult to treat aggressively without affecting the rest of the brain. METHODOLOGYHigh-energy, short-range (40-80{micro}m) dendrimer-delivered -particles could address both challenges, because (1) they cause complex, highly cytotoxic double-strand DNA breaks, and (2) irradiation of the neighboring brain is minimal, since dendrimers selectively delivers them to tumors. Since cancer cells that are not directly hit by -particles will likely not be killed, the patterns of tumor irradiation affect efficacy. Systemically injected dendrimers extensively accumulate in glioblastomas, where they are taken up by tumor associated macrophages (TAMs), which tend to infiltrate tumors. We hypothesized that dendrimers labeled with -particle emitters, when being carried by TAMs, could more evenly irradiate glioblastomas, improving survival. In this study, the efficacy of dendrimers radiolabeled with the -particle emitter actinium-225 (dendrimer-radioconjugates) was evaluated when administered alone and/or after temozolomide, in a syngeneic immune-competent orthotopic GL261-C57BL/6 mouse model. RESULTSSystemically-administered dendrimer-radioconjugates, at activities that did not result in long-term toxicities, prolonged survival of mice with orthotopic GL261 tumors, compared to standard-of-care temozolomide (39 vs 31 days mean survival, p=0.0061) and non-treated animals (30 days, p=0.0009). Importantly, injection of temozolomide 24 hours before administration of dendrimer-radioconjugates further improved survival remarkably (44 days). This improvement in efficacy was attributed to: (1) the significant increase (by 33%) in tumor absorbed doses delivered by dendrimer-radioconjugates when injected after chemotherapy, without altering normal organ dosimetry, while sparing the tumor-surrounding healthy brain; (2) the potentially deeper tumor penetration of dendrimer-radioconjugates, suggested by the enhancement of dendrimer penetration within GL261-spheroids, employed as model tumor-avascular regions and/or TAM-free regions; and/or (3) the formation of a more lethal cocktail when both modalities acted on same cancer cells, that was correlated with increased levels of dendrimer-radioconjugates associating with GL261 cells in vitro and with greater incidences of karyomegaly in vivo. CONCLUSIONSThis study demonstrates the potential of a brain tumor targeted systemic actinium-225 radiopharmaceutical therapy that inhibits growth of glioblastoma cells and prolongs survival of mice with orthotopic brain tumors, further improved by standard-of-care temozolomide, without notable toxicities.

bioengineering↗

bioRxiv2023

Combined, yet Separate: cocktails of carriers (not drugs) for α-particle therapy of solid tumors expressing moderate-to-low levels of targetable markers

Alpha-particle radionuclide-antibody conjugates are being clinically evaluated against solid cancers expressing moderate levels of the targeted markers, with promising results. These findings are attributed to the high killing power of alpha-particles in spite of the expected decrease in antibody tumor uptake, that reduces tumor absorbed doses. However, when tumor absorbed doses are reduced, addressing the heterogeneities in delivery of alpha-particles within solid tumors (i.e. enabling uniform irradiation patterns) becomes critical: to maintain efficacy, the fewer alpha-particles delivered within tumors need to traverse/hit as many different cancer cells as possible. This proof-of-concept study describes an approach to complement the antibody- targeted radiotherapy by using a separate carrier to deliver a fraction of the injected radioactivity to tumor regions geographically different than those affected by the antibody; collectively, the two carriers should distribute the alpha-particle emitters, Actinium-225 in particular, more uniformly within tumors maintaining efficacy. MethodsWe monitored the extent(s) of tumor growth inhibition, onset delay of spontaneous metastases and/or survival on orthotopic MDA-MB-213 and MDA-MB-436 triple negative breast cancer mouse models and on an ectopic BxPC3 pancreatic cancer mouse model, treated systemically with the two separate carriers. Tumors were chosen to express different (but low) levels of HER1, utilized as a model antibody-targeted marker. ResultsIndependent of tumor origin and/or resistance to chemotherapy, the two separate carriers: (a) improved the primary tumor growth inhibition, (b) eliminated the formation of spontaneous metastases, and/or (c) prolonged survival, at lower or comparable tumor delivered doses relative to the antibody alone, without noticeable off-target toxicities. ConclusionThis tumor-agnostic strategy is timely and could be used to enhance the efficacy of existing alpha-particle radionuclide-antibody treatments without increasing, possibly even reducing, the total administered radioactivity.

bioengineering↗

bioRxiv2023

ME3BP-7 is a targeted cytotoxic agent that rapidly kills pancreatic cancer cells expressing high levels of monocarboxylate transporter MCT1

Nearly 30% of Pancreatic ductal adenocarcinoma (PDAC)s exhibit a marked overexpression of Monocarboxylate Transporter 1 (MCT1) offering a unique opportunity for therapy. However, biochemical inhibitors of MCT1 have proven unsuccessful in clinical trials. In this study we present an alternative approach using 3-Bromopyruvate (3BP) to target MCT1 overexpressing PDACs. 3BP is a cytotoxic agent that is known to be transported into cells via MCT1, but its clinical usefulness has been hampered by difficulties in delivering the drug systemically. We describe here a novel microencapsulated formulation of 3BP (ME3BP-7), that is effective against a variety of PDAC cells in vitro and remains stable in serum. Furthermore, systemically administered ME3BP-7 significantly reduces pancreatic cancer growth and metastatic spread in multiple orthotopic models of pancreatic cancer with manageable toxicity. ME3BP-7 is, therefore, a prototype of a promising new drug, in which the targeting moiety and the cytotoxic moiety are both contained within the same single small molecule. One Sentence SummaryME3BP-7 is a novel formulation of 3BP that resists serum degradation and rapidly kills pancreatic cancer cells expressing high levels of MCT1 with tolerable toxicity in mice.

cancer biology↗

bioRxiv2021

Bionized nanoferrite particles alter the course of experimental Cryptococcus neoformans pneumonia

Cryptococcosis is a devastating fungal disease associated with high morbidity and mortality even when treated with antifungal drugs. Bionized nanoferrite (BNF) nanoparticles are powerful immunomodulators, but their efficacy for infectious diseases has not been investigated. Administration of BNF nanoparticles to mice with experimental cryptococcal pneumonia altered the outcome of infection in a dose response manner as measured by colony forming units and survival. The protective effects were higher at lower doses, with reductions in IL-2, IL-4 and TNF-, consistent with immune modulation whereby reductions in inflammation translate into reduced host damage, clearance of infection and longer survival.

microbiology↗