Here, we utilized spontaneous models of pancreatic and lung cancer to examine how neoantigenicity shapes tumor immunity and progression. As expected, neoantigen expression during lung adenocarcinoma ...development leads to T cell-mediated immunity and disease restraint. By contrast, neoantigen expression in pancreatic ductal adenocarcinoma (PDAC) results in exacerbation of a fibro-inflammatory microenvironment that drives disease progression and metastasis. Pathogenic TH17 responses are responsible for this neoantigen-induced tumor progression in PDAC. Underlying these divergent T cell responses in pancreas and lung cancer are differences in infiltrating conventional dendritic cells (cDCs). Overcoming cDC deficiency in early-stage PDAC leads to disease restraint, while restoration of cDC function in advanced PDAC restores tumor-restraining immunity and enhances responsiveness to radiation therapy.
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•Neoantigen expression elicits pathogenic T cell response accelerating PDAC•cDC dysfunction precludes early TH1 and CTL response to PDAC neoantigens•Increasing cDCs in early PDAC lesions restores anti-tumor T cell immunity•Restoring cDC function in advanced PDAC improves efficacy of radiation therapy
Hegde et al. identify divergent T cell responses in lung cancer and pancreatic ductal adenocarcinoma (PDAC) caused by differences in conventional dendritic cell (cDC) infiltration. Mobilization of cDCs in PDAC models enhances CD8+ T cell and TH1 activity to reduce tumor growth and increase response to therapy.
Cardiac radiotherapy (RT) may be effective in treating heart failure (HF) patients with refractory ventricular tachycardia (VT). The previously proposed mechanism of radiation-induced fibrosis does ...not explain the rapidity and magnitude with which VT reduction occurs clinically. Here, we demonstrate in hearts from RT patients that radiation does not achieve transmural fibrosis within the timeframe of VT reduction. Electrophysiologic assessment of irradiated murine hearts reveals a persistent supraphysiologic electrical phenotype, mediated by increases in Na
1.5 and Cx43. By sequencing and transgenic approaches, we identify Notch signaling as a mechanistic contributor to Na
1.5 upregulation after RT. Clinically, RT was associated with increased Na
1.5 expression in 1 of 1 explanted heart. On electrocardiogram (ECG), post-RT QRS durations were shortened in 13 of 19 patients and lengthened in 5 patients. Collectively, this study provides evidence for radiation-induced reprogramming of cardiac conduction as a potential treatment strategy for arrhythmia management in VT patients.
PI3K/AKT pathway alterations are associated with incomplete response to chemoradiation in human cervical cancer. This study was performed to test for mutations in the PI3K pathway and to evaluate the ...effects of AKT inhibitors on glucose uptake and cell viability.
Mutational analysis of DNA from 140 pretreatment tumor biopsies and 8 human cervical cancer cell lines was performed. C33A cells (PIK3CAR88Q and PTENR233*) were treated with increasing concentrations of two allosteric AKT inhibitors (SC-66 and MK-2206) with or without the glucose analogue 2-deoxyglucose (2-DG). Cell viability and activation status of the AKT/mTOR pathway were determined in response to the treatment. Glucose uptake was evaluated by incubation with 18F-fluorodeoxyglucose (FDG). Cell migration was assessed by scratch assay.
Activating PIK3CA (E545K, E542K) and inactivating PTEN (R233*) mutations were identified in human cervical cancer. SC-66 effectively inhibited AKT, mTOR and mTOR substrates in C33A cells. SC-66 inhibited glucose uptake via reduced delivery of Glut1 and Glut4 to the cell membrane. SC-66 (1 µg/ml-56%) and MK-2206 (30 µM-49%) treatment decreased cell viability through a non-apoptotic mechanism. Decreases in cell viability were enhanced when AKT inhibitors were combined with 2-DG. The scratch assay showed a substantial reduction in cell migration upon SC-66 treatment.
The mutational spectrum of the PI3K/AKT pathway in cervical cancer is complex. AKT inhibitors effectively block mTORC1/2, decrease glucose uptake, glycolysis, and decrease cell viability in vitro. These results suggest that AKT inhibitors may improve response to chemoradiation in cervical cancer.
Copper plays a dual role as a nutrient and a toxin during bacterial infections. While uropathogenic Escherichia coli (UPEC) strains can use the copper-binding metallophore yersiniabactin (Ybt) to ...resist copper toxicity, Ybt also converts bioavailable copper to Cu(II)-Ybt in low-copper conditions. Although E. coli have long been considered to lack a copper import pathway, we observed Ybt-mediated copper import in UPEC using canonical Fe(III)-Ybt transport proteins. UPEC removed copper from Cu(II)-Ybt with subsequent re-export of metal-free Ybt to the extracellular space. Copper released through this process became available to an E. coli cuproenzyme (the amine oxidase TynA), linking this import pathway to a nutrient acquisition function. Ybt-expressing E. coli thus engage in nutritional passivation, a strategy of minimizing a metal ion's toxicity while preserving its nutritional availability. Copper acquisition through this process may contribute to the marked virulence defect of Ybt-transport-deficient UPEC.
Peptide receptor radionuclide therapy (PRRT) is an important treatment option for patients with somatostatin receptor-2 (SSTR2)-expressing neuroendocrine tumour (NET) though tumour regression occurs ...in only a minority of patients. Therefore, novel PRRT regimens with improved therapeutic activity are needed. Radiation induced DNA damage repair is an attractive therapeutic target to increase PRRT efficacy and consequently, we have characterised a panel of preclinical models for their SSTR2 expression, in vivo growth properties and response to 177Lu-DOTA-octreotate (LuTate) PRRT to identify models with features suitable for evaluating novel therapeutic combinations. In vitro studies using the SSTR2 expressing AR42J model demonstrate that the combination of LuTate and the small molecule Poly(ADP-ribose) polymerase-1 (PARP) inhibitor, talazoparib led to increased DNA double strand breaks, as assessed by γ-H2AX foci formation, as compared to LuTate alone. Furthermore, using the AR42J tumour model in vivo we demonstrate that the combination of LuTate and talazoparib significantly improved the anti-tumour efficacy of LuTate alone. These findings support the clinical evaluation of the combination of LuTate and PARP inhibition in SSTR2-expressing NET.
Alzheimer’s Disease (AD) is the most common neurodegenerative disease, and efficient therapeutic and early diagnostic agents for AD are still lacking. Herein, we report the development of a novel ...amphiphilic compound, LS-4, generated by linking a hydrophobic amyloid-binding distyrylbenzene fragment with a hydrophilic triazamacrocycle, which dramatically increases the binding affinity toward various amyloid β (Aβ) peptide aggregates, especially for soluble Aβ oligomers. Moreover, upon the administration of LS-4 to 5xFAD mice, fluorescence imaging of LS-4-treated brain sections reveals that LS-4 can penetrate the blood-brain barrier and bind to the Aβ oligomers in vivo. In addition, the treatment of 5xFAD mice with LS-4 reduces the amount of both amyloid plaques and associated phosphorylated tau aggregates vs the vehicle-treated 5xFAD mice, while microglia activation is also reduced. Molecular dynamics simulations corroborate the observation that introducing a hydrophilic moiety into the molecular structure of LS-4 can enhance the electrostatic interactions with the polar residues of the Aβ species. Finally, exploiting the Cu2+-chelating property of the triazamacrocycle, we performed a series of imaging and biodistribution studies that show the 64Cu-LS-4 complex binds to the amyloid plaques and can accumulate to a significantly larger extent in the 5xFAD mouse brains vs the wild-type controls. Overall, these results illustrate that the novel strategy, to employ an amphiphilic molecule containing a hydrophilic moiety attached to a hydrophobic amyloid-binding fragment, can increase the binding affinity for both soluble and insoluble Aβ aggregates and can thus be used to detect and regulate various Aβ species in AD.
Significance
Immune checkpoint therapy (ICT) has led to durable responses in a subset of cancer patients. Generally, patients who respond to ICT bear tumors with high mutational burden. Radiation is ...used for treatment of many types of cancers and has been shown to induce new mutations in treated tumor cells and to synergistically facilitate ICT. However, these latter actions have largely been explained by radiation-induced tumor cell death and/or effects on the host. Herein, we show that noncurative irradiation induces mutations in tumor cells lacking neoantigens and that these de novo-generated neoantigens function as targets for CD8
+
T cells, resulting in increased immunogenicity of nonimmunogenic tumor cells. This study thus identifies an additional mechanism that explains synergy between immunotherapy and radiation.
Immunotherapies are a promising advance in cancer treatment. However, because only a subset of cancer patients benefits from these treatments it is important to find mechanisms that will broaden the responding patient population. Generally, tumors with high mutational burdens have the potential to express greater numbers of mutant neoantigens. As neoantigens can be targets of protective adaptive immunity, highly mutated tumors are more responsive to immunotherapy. Given that external beam radiation 1) is a standard-of-care cancer therapy, 2) induces expression of mutant proteins and potentially mutant neoantigens in treated cells, and 3) has been shown to synergize clinically with immune checkpoint therapy (ICT), we hypothesized that at least one mechanism of this synergy was the generation of de novo mutant neoantigen targets in irradiated cells. Herein, we use Kras
G12D
x p53
−/−
sarcoma cell lines (KP sarcomas) that we and others have shown to be nearly devoid of mutations, are poorly antigenic, are not controlled by ICT, and do not induce a protective antitumor memory response. However, following one in vitro dose of 4- or 9-Gy irradiation, KP sarcoma cells acquire mutational neoantigens and become sensitive to ICT in vivo in a T cell-dependent manner. We further demonstrate that some of the radiation-induced mutations generate cytotoxic CD8
+
T cell responses, are protective in a vaccine model, and are sufficient to make the parental KP sarcoma line susceptible to ICT. These results provide a proof of concept that induction of new antigenic targets in irradiated tumor cells represents an additional mechanism explaining the clinical findings of the synergy between radiation and immunotherapy.
While Alzheimer's Disease (AD) is the most common neurodegenerative disease, there is still a dearth of efficient therapeutic and diagnostic agents for this disorder. Reported herein are a series of ...new multifunctional compounds (MFCs) with appreciable affinity for amyloid aggregates that can be potentially used for both the modulation of Aβ aggregation and its toxicity, as well as positron emission tomography (PET) imaging of Aβ aggregates. Firstly, among the six compounds tested
HYR-16
is shown to be capable to reroute the toxic Cu-mediated Aβ oligomerization into the formation of less toxic amyloid fibrils. In addition,
HYR-16
can also alleviate the formation of reactive oxygen species (ROS) caused by Cu
2+
ions through Fenton-like reactions. Secondly, these MFCs can be easily converted to PET imaging agents by pre-chelation with the
64
Cu radioisotope, and the Cu complexes of
HYR-4
and
HYR-17
exhibit good fluorescent staining and radiolabeling of amyloid plaques both
in vitro
and
ex vivo
. Importantly, the
64
Cu-labeled
HYR-17
is shown to have a significant brain uptake of up to 0.99 ± 0.04 %ID per g. Overall, by evaluating the various properties of these MFCs valuable structure-activity relationships were obtained that should aid the design of improved therapeutic and diagnostic agents for AD.
A series of multifunctional compounds and their
64
Cu complexes exhibit good affinity for Aβ aggregates and can also control Aβ toxicity.
Idiopathic pulmonary fibrosis (IPF) is a progressive inflammatory lung disease without effective molecular markers of disease activity or treatment responses. Monocyte and interstitial macrophages ...that express the C-C motif CCR2 (chemokine receptor 2) are active in IPF and central to fibrosis.
To phenotype patients with IPF for potential targeted therapy, we developed
Cu-DOTA-ECL1i, a radiotracer to noninvasively track CCR2
monocytes and macrophages using positron emission tomography (PET).
CCR2
cells were investigated in mice with bleomycin- or radiation-induced fibrosis and in human subjects with IPF. The CCR2
cell populations were localized relative to fibrotic regions in lung tissue and characterized using immunolocalization, single-cell mass cytometry, and
RNA
hybridization and then correlated with parallel quantitation of lung uptake by
Cu-DOTA-ECL1i PET.
Mouse models established that increased
Cu-DOTA-ECL1i PET uptake in the lung correlates with CCR2
cell infiltration associated with fibrosis (
= 72). As therapeutic models, the inhibition of fibrosis by IL-1β blockade (
= 19) or antifibrotic pirfenidone (
= 18) reduced CCR2
macrophage accumulation and uptake of the radiotracer in mouse lungs. In lung tissues from patients with IPF, CCR2
cells concentrated in perifibrotic regions and correlated with radiotracer localization (
= 21). Human imaging revealed little lung uptake in healthy volunteers (
= 7), whereas subjects with IPF (
= 4) exhibited intensive signals in fibrotic zones.
These findings support a role for imaging CCR2
cells within the fibrogenic niche in IPF to provide a molecular target for personalized therapy and monitoring.Clinical trial registered with www.clinicaltrials.gov (NCT03492762).
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