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Nature Communications Jun 2017Radiotherapy is under investigation for its ability to enhance responses to immunotherapy. However, the mechanisms by which radiation induces anti-tumour T cells remain...
Radiotherapy is under investigation for its ability to enhance responses to immunotherapy. However, the mechanisms by which radiation induces anti-tumour T cells remain unclear. We show that the DNA exonuclease Trex1 is induced by radiation doses above 12-18 Gy in different cancer cells, and attenuates their immunogenicity by degrading DNA that accumulates in the cytosol upon radiation. Cytosolic DNA stimulates secretion of interferon-β by cancer cells following activation of the DNA sensor cGAS and its downstream effector STING. Repeated irradiation at doses that do not induce Trex1 amplifies interferon-β production, resulting in recruitment and activation of Batf3-dependent dendritic cells. This effect is essential for priming of CD8 T cells that mediate systemic tumour rejection (abscopal effect) in the context of immune checkpoint blockade. Thus, Trex1 is an upstream regulator of radiation-driven anti-tumour immunity. Trex1 induction may guide the selection of radiation dose and fractionation in patients treated with immunotherapy.
Topics: Animals; Basic-Leucine Zipper Transcription Factors; CD8-Positive T-Lymphocytes; CTLA-4 Antigen; Cell Line, Tumor; Dendritic Cells; Exodeoxyribonucleases; Female; Gene Expression Regulation; HEK293 Cells; Humans; Immunotherapy; Interferon-beta; Mammary Neoplasms, Animal; Membrane Proteins; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Neoplasms; Nucleotidyltransferases; Phosphoproteins; Receptor, Interferon alpha-beta; Repressor Proteins
PubMed: 28598415
DOI: 10.1038/ncomms15618 -
Journal of Nuclear Medicine : Official... May 2021Treatment of advanced metastatic castration-resistant prostate cancer after failure of approved therapy options remains challenging. Prostate-specific membrane antigen...
Treatment of advanced metastatic castration-resistant prostate cancer after failure of approved therapy options remains challenging. Prostate-specific membrane antigen (PSMA)-targeting β- and α-emitters have been introduced, with promising response rates. Here, we present the first-to our knowledge-clinical data for PSMA-targeted α-therapy (TAT) using Ac-PSMA imaging and therapy (I&T). Fourteen patients receiving Ac-PSMA-I&T were included in this retrospective analysis. Eleven of the 14 had prior second-line antiandrogen treatment with abiraterone or enzalutamide, prior chemotherapy, and prior Lu-PSMA treatment. Patients were treated at bimonthly intervals until progression or intolerable side effects. Prostate-specific antigen (PSA) was measured for response assessment. Hematologic and nonhematologic side effects were recorded according to the Common Terminology Criteria for Adverse Events, version 5.0. Thirty-four cycles of Ac-PSMA-I&T were applied (median dose, 7.8 MBq; range, 6.0-8.5), with 1 cycle in 3 patients, 2 cycles in 7 patients, 4 cycles in 3 patients, and 5 cycles in 1 patient. No acute toxicity was observed during hospitalization. Baseline PSA was 112 ng/mL (range, 20.5-818 ng/mL). The best PSA response after TAT (a PSA decline ≥ 50%) was observed in 7 patients, and a PSA decline of any amount was observed in 11 patients. Three patients had no PSA decline at any time. A subgroup analysis of 11 patients with prior Lu-PSMA treatment showed any PSA decline in 8 patients and a decline of at least 50% in 5 patients. After TAT, grade 3 anemia was observed in 3 of the 14 patients, with 2 of them presenting with grade 2 anemia already at baseline. Grade 3 leukopenia was observed in 1 patient. Eight patients with preexisting xerostomia after Lu-PSMA showed no worsening after TAT. Newly diagnosed grade 1 or 2 xerostomia after TAT was observed in 5 patients. One patient reported no xerostomia at all. Our first clinical data for TAT using Ac-PSMA-I&T showed a promising antitumor effect in advanced metastatic castration-resistant prostate cancer. These results are highly comparable to data on Ac-PSMA-617 TAT.
Topics: Actinium; Antigens, Surface; Beta Particles; Glutamate Carboxypeptidase II; Humans; Male; Middle Aged; Molecular Targeted Therapy; Neoplasm Metastasis; Prostatic Neoplasms, Castration-Resistant; Retrospective Studies; Treatment Outcome
PubMed: 33008928
DOI: 10.2967/jnumed.120.251017 -
Journal of Nuclear Medicine : Official... Dec 2016Prostate-specific membrane antigen (PSMA) is a promising target in prostate cancer. Recently, we started the first-in-human treatment with an α-radionuclide-labeled...
UNLABELLED
Prostate-specific membrane antigen (PSMA) is a promising target in prostate cancer. Recently, we started the first-in-human treatment with an α-radionuclide-labeled PSMA ligand. Although the case series is still ongoing, we here report in advance about two patients in highly challenging clinical situations who showed a complete response to Ac-PSMA-617 therapy.
METHODS
Ga-PSMA-11 PET/CT validated the presence of the PSMA-positive tumor phenotype. A 100-kBq activity of Ac-PSMA-617 per kilogram of body weight was administered bimonthly. Prostate-specific antigen response and hematologic toxicity were measured at least every 4 wk. Restaging was performed with Ga-PSMA-11 PET/CT.
RESULTS
Both patients experienced a prostate-specific antigen decline to below the measurable level and showed a complete response on imaging. No relevant hematologic toxicity was observed. Xerostomia was the only mentionable clinical side effect.
CONCLUSION
Targeted α-therapy with Ac-PSMA-617, although still experimental, obviously has strong potential to significantly benefit advanced-stage prostate cancer patients.
Topics: Actinium; Alpha Particles; Antigens, Surface; Beta Particles; Dipeptides; Glutamate Carboxypeptidase II; Heterocyclic Compounds, 1-Ring; Humans; Lutetium; Male; Neoplasm Metastasis; Positron Emission Tomography Computed Tomography; Prostate-Specific Antigen; Prostatic Neoplasms, Castration-Resistant; Radioisotopes
PubMed: 27390158
DOI: 10.2967/jnumed.116.178673 -
Cancers Aug 2021Prostate cancer (PCa) causes significant morbidity and mortality in men globally. While localized PCa may be managed with curative intent by surgery and/or radiation... (Review)
Review
Prostate cancer (PCa) causes significant morbidity and mortality in men globally. While localized PCa may be managed with curative intent by surgery and/or radiation therapy, the management of advanced hormone resistant metastatic disease (mCRPC) is more challenging. Theranostics is a principle based on the ability to use an organ specific ligand and label it to both a diagnostic and a therapeutic agent. The overexpression of prostate specific membrane antigen (PSMA) on prostate cancer cells creates a unique opportunity for development of targeted radionuclide therapy. The use of both beta and alpha emitting particles has shown great success. Several clinical trials have been initiated assessing the efficacy and safety profile of these radionuclide agents. The results are encouraging with PSMA directed radioligand therapy performing well in patients who have exhausted all other standard treatment options. Future studies need to assess the timing of introduction of these radionuclide therapies in the management schema of mCRPC. Drugs or therapies are not without side effects and targeted radionuclide therapies presents a new set of toxicities including xerostomia and myelosuppression. New therapeutic strategies are being explored to improve outcomes while keeping toxicities to a minimum. This review aims to look at the various PSMA labelled tracers that form part of the theragnostic approach and subsequently delve into the progress made in the area of radionuclide therapy.
PubMed: 34359805
DOI: 10.3390/cancers13153904 -
Frontiers in Medicine 2022According to the 2021 World Health Organization Classification of Tumors of the Central Nervous System, glioblastoma (GB) is a primary brain tumor and presents with the... (Review)
Review
According to the 2021 World Health Organization Classification of Tumors of the Central Nervous System, glioblastoma (GB) is a primary brain tumor and presents with the worst prognosis. Due to its infiltrating characteristic, molecular heterogeneity, and only partly preserved function of the blood-brain barrier, the median overall survival time is short (9-15 months), regardless of comprehensive treatment including surgery, radiotherapy, and chemotherapy. Several novel treatment strategies are under investigation. Unfortunately, none of them produced successful results; 90% of patients have a recurrence of the disease within 6 months. Local administration of the drug could be a promising approach to delivering treatment with minimized side effects, due to the recurrence of 95% glioblastomas in a margin of 2 cm at the primary site. Several ligand-receptor systems have been evaluated, such as targeting tenascin, the extracellular matrix protein, or radiolabeled somatostatin analogs, as it is overexpressed with the SSTR-2 receptor system in around 80% of gliomas. Moreover, this study revealed that the NK-1 receptor is overexpressed in GB, suggesting that substance P (SP) may serve as a ligand. A variety of radioisotopes, beta- (I, Y, or Lu) and alpha emitters (Bi, Ac, or At), with different physical properties were tested for treatment. Alpha particles have many advantages over beta radiation such as short range with higher linear energy transfer. According to that characteristic, it is extremely dose delivered to the targeted cells, while reducing harm to nearby healthy tissue. Additionally, the biological effect of alpha radiation is independent of the cell cycle phase, cell oxygenation and O-6-methylguanine-DNA methyltransferase () gene promoter methylation status. In this article, we summarize the experience with local treatment of primary and secondary GBs with locally used radioisotopes such as [Bi]Bi-DOTA-SP or [Ac]Ac-DOTA-SP.
PubMed: 36590948
DOI: 10.3389/fmed.2022.1085245 -
Seminars in Interventional Radiology Oct 2021Transarterial radioembolization with yttrium-90 ( Y) is a mainstay for the treatment of liver cancer. Imaging the distribution following delivery is a concept that... (Review)
Review
Transarterial radioembolization with yttrium-90 ( Y) is a mainstay for the treatment of liver cancer. Imaging the distribution following delivery is a concept that dates back to the 1960s. As β particles are created during Y decay, bremsstrahlung radiation is created as the particles interact with tissues, allowing for imaging with a gamma camera. Inherent qualities of bremsstrahlung radiation make its imaging difficult. SPECT and SPECT/CT can be used but suffer from limitations related to low signal-to-noise bremsstrahlung radiation. However, with optimized imaging protocols, clinically adequate images can still be obtained. A finite but detectable number of positrons are also emitted during Y decay, and many studies have demonstrated the ability of commercial PET/CT and PET/MR scanners to image these positrons to understand Y distribution and help quantify dose. PET imaging has been proven to be superior to SPECT for quantitative imaging, and therefore will play an important role going forward as we try and better understand dose/response and dose/toxicity relationships to optimize personalized dosimetry. The availability of PET imaging will likely remain the biggest barrier to its use in routine post- Y imaging; thus, SPECT/CT imaging with optimized protocols should be sufficient for most posttherapy subjective imaging.
PubMed: 34629714
DOI: 10.1055/s-0041-1735569 -
Iranian Journal of Pharmaceutical... 2019Depleted uranium (DU) is an important by product in uranium enrichment process. Due to its applications in civilian and also military activity, DU emerged as... (Review)
Review
Depleted uranium (DU) is an important by product in uranium enrichment process. Due to its applications in civilian and also military activity, DU emerged as environmental pollutant. The exposure to DU can occur via external or internal pathways. In external exposure, mainly beta radiation from the decay products contributes to DU toxicity. Internal exposure to DU is more important and can occur through ingestion of DU-contaminated water and food and inhalation of DU aerosols. There is limited information about health effects and mechanism of DU after environmental exposure. Kidney is reported as the main target organ for the chemical toxicity of this metal that was reported in Persian Gulf syndrome. Alterations in behavior, some neurologic adverse effects, immunotoxicity, embryo-toxicity and hepatotoxicity were observed in chronic exposure to DU. Also, the increased risk of cancer was revealed in epidemiological and experimental studies. Several mechanisms were suggested for DU toxicity such as oxidative stress, mitochondrial toxicity and inflammation. In fact, uranium like other toxic heavy metals can induce oxidative damage and apoptosis via mitochondrial pathway and inflammatory response. In this review, we have discussed the kinetic of DU including source and exposure pathway. In addition, the health effects of DU and also its toxic mechanism have been highlighted.
PubMed: 32802091
DOI: 10.22037/ijpr.2020.113045.14085