Tumor radioresistance and severe toxicity make reirradiation for recurrent nasopharyngeal carcinoma (NPC) a significant clinical challenge. This study aims to investigate the ability of the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib to sensitize recurrent NPC cells irradiated with photon or carbon ion (C-ion), and to explore the underlying mechanism of the synergistic promotion of cell death by olaparib and ionizing radiation. The results show that olaparib has significant X-ray and C-ion radiosensitization effects on recurrent NPC cells and the associated HK-RR photon-resistant model. Radiation, particularly C-ion exposure, induces a homologous recombination (HR)-deficient gene signature in HR-proficient NPC cells, potentially increasing their sensitivity to PARP inhibition. C-ion and X-ray irradiation induces similar modes of cell death, and multiple cell death pathways [including apoptosis, necrosis, ferroptosis, senescence, and autophagic cell death (ACD)] contribute to the cytotoxic effects of radiation combined with olaparib, with ACD being the dominant pathway. Both the pharmacological and genetic inhibition of autophagy significantly attenuate the radiosensitization effect of olaparib. In conclusion, olaparib effectively sensitizes recurrent NPC cells to both X-ray irradiation and C-ion irradiation, with autophagy playing a central role in mediating this effect.

Glioblastoma (GBM), the most prevalent and lethal primary malignancy of the central nervous system, remains refractory to conventional photon radiotherapy due to inherent limitations in dose distribution. Although carbon ion radiotherapy offers distinct advantages, including its characteristic Bragg peak deposition and superior relative biological effectiveness, its clinical application is constrained by high costs and increased toxicity. This study explores the radiobiological interactions underlying a mixed carbon ion-photon irradiation regimen, a promising strategy in advanced particle therapy. Our findings demonstrate that combined irradiation exerts synergistic cytotoxic effects in GBM models. Mechanistic analysis reveals that this combination induces clustered DNA double-strand breaks, leading to the cytoplasmic accumulation of double-stranded DNA (dsDNA) fragments. This, in turn, activates the cGAS-STING-mediated cytosolic DNA sensing pathway, which facilitates NCOA4-FTH1 axis-driven ferritinophagy and ultimately triggering iron-dependent ferroptosis. These findings offer a new mechanistic perspective on optimizing combined particle therapy regimens for GBM treatment, with significant implications for translational applications in clinical radiation oncology.

INTRODUCTION:Despite significant advances in the comprehensive treatment of nasopharyngeal carcinoma (NPC), local recurrence or distant metastasis still occurs in a considerable proportion of patients, leading to poor outcomes and posing a significant clinical challenge. The current therapeutic agent, Triptonide (TN), has shown potential efficacy in modulating cellular autophagy, suggesting its therapeutic promise for treating NPC. However, the precise molecular targets and mechanisms underlying TN's role in NPC remain to be elucidated. METHODS:Initially, relevant targets for TN in the treatment of NPC were identified through public databases. Next, network pharmacology and bioinformatics analyses were employed to pinpoint the top 15 hub targets and critical signaling pathways involved in TN's therapeutic action. Finally, experimental validation, including a range of molecular assays, was conducted to investigate the cellular effects of TN treatment, such as apoptosis induction, migration inhibition, Caspase-3 activation, mitochondrial dysfunction, autophagy-related gene expression, and TFAM level detection, thereby confirming the essential genes and pathways. RESULTS:A total of 31 potential molecular targets for TN in NPC were identified, with 27 genes confirmed through autophagy-related gene analysis. Among these, the top 15 hub genes included RELA, CASP8, NFKBIA, PPARG, PTGS2, MAPK14, MAPK8, HDAC1, ERBB2, CASP1, TERT, AR, CDK1, PGR, and HDAC6. TN was found to activate the MAPK signaling pathway. In vitro, TN induced NPC cell apoptosis via increased ROS, MAPK14 activation, and Caspase-3 cleavage. It disrupted mitochondrial function (reduced membrane potential, decreased copy number, enhanced fission), inhibited mTOR and RELA phosphorylation, and promoted autophagy. TN also caused S-phase arrest, reduced CDH3, and increased CDH1. Lipoic acid partially reversed TN-induced cytotoxicity. DISCUSSION:TN exerts anti-NPC effects primarily through MAPK pathway activation and autophagy induction. Key targets mediating these effects include RELA, CASP8, PPARG, MAPK14, MAPK8, HDAC1, ERBB2, and CASP1. The reversal by lipoic acid implicates ROS in TN's mechanism. The disruption of mitochondrial function represents a critical facet of its action. CONCLUSION:TN demonstrates potential as a therapeutic agent for NPC, primarily through activation of the MAPK signaling pathway and autophagy. Key targets, including RELA, CASP8, PPARG, MAPK14, MAPK8, HDAC1, ERBB2, and CASP1, have been identified as critical mediators of TN's effects, highlighting its role in promoting autophagy and enhancing NPC treatment.

Nasopharyngeal carcinoma (NPC) is highly sensitive to ionizing radiation, and radiation therapy is the mainstay treatment modality for nonmetastatic disease. For decades, NPC radiation therapy has utilized conventional treatment using two-dimensional, and lately three-dimensional, techniques and intensity-modulated radiation therapy (IMRT). Disease control using conventional radiotherapy techniques has been acceptable; however, insufficient dose to parts of the targets owing to the proximity of the primary disease to critical structures such as optic chiasm, spinal cord, and/or brainstem may result in reduced disease control in locally advanced NPC. Although the local control of T1 and T2 NPC ranges between 76.6% and 93%, the reported overall local control rates were between 58% and 79% in patients with locally advanced NPC treated with conventional radiation (Hunt et al. 2001; Leung et al. 2005; Au et al. 2003; Chua et al. 2001; Lee et al. 2005).

Although radiotherapy continues to evolve as a mainstay of the oncological armamentarium, research and innovation in radiotherapy in low-income and middle-income countries (LMICs) faces challenges. This third Series paper examines the current state of LMIC radiotherapy research and provides new data from a 2022 survey undertaken by the International Atomic Energy Agency and new data on funding. In the context of LMIC-related challenges and impediments, we explore several developments and advances—such as deep phenotyping, real-time targeting, and artificial intelligence—to flag specific opportunities with applicability and relevance for resource-constrained settings. Given the pressing nature of cancer in LMICs, we also highlight some best practices and address the broader need to develop the research workforce of the future. This Series paper thereby serves as a resource for radiation professionals.

BACKGROUND:Salivary Adenoid Cystic Carcinoma (ACC) is characterized by a highly invasive and slow-growing pattern, and its etiology remains unidentified. Triptonide (TN) has demonstrated efficacy as a pharmacotherapeutic agent against ACC. Nonetheless, the specific targets and mechanism of molecular action underlying the effectiveness of TN in treating ACC have not been elucidated. OBJECTIVES:By integrating network pharmacology within laboratory experiments, this research delves into the prospective targets and molecular mechanisms associated with the application of TN in treating ACC. METHODS:Initially, pertinent targets associated with TN against ACC were acquired from public databases. Subsequently, a combination of network pharmacology and bioinformatics analysis was utilized to screen the top 10 hub targets and key signal pathways of TN-treating ACC. Finally, in vitro experiments involving various molecular assays were conducted to evaluate the biological phenotypes of cells following TN treatment, encompassing assessments of apoptosis levels, plate migration, and other parameters, thereby validating pivotal genes and pathways. RESULTS:A total of 23 pertinent targets for TN in relation to ACC were identified, with the top 10 hub genes being MAPK8, PTGS2, RELA, MAPK14, NR3C1, HDAC1, PPARG, NFKBIA, AR, and PGR. There was a significant correlation between the TNF signaling pathway and the treatment of ACC with TN. In vitro experiments demonstrated that TN treatment elevated RELA phosphorylation while concurrently reducing MAPK14 phosphorylation and inducing G2/M arrest. TN exhibited the ability to enhance the apoptosis rate through increased caspase-3 activity, elevated levels of Reactive Oxygen Species (ROS), mitochondrial dysfunction, and inhibition of cell migration. CONCLUSION:There is a potential therapeutic role for TN in the treatment of ACC through the activation of the TNF signaling pathway. Among the identified candidates, MAPK8, HDAC1, PTGS2, RELA, NR3C1, PPARG, NFKBIA, AR, and PGR emerge as the most pertinent therapeutic targets for TN in the context of ACC treatment.

Tribbles pseudokinase 3 (TRIB3) has been identified recently as a novel oncogene in several cancers. Still, further extensive research is imperative to elucidate its function and the molecular mechanisms underlying its involvement in the progression of head and neck squamous cell carcinoma (HNSCC). In our study, we found that TRIB3 silencing significantly promoted cell death by inducing ferroptosis. The interaction of TRIB3 with Transcription Factor 4 (TCF4) and β-catenin created a heterotrimeric complex, which directly interacts with the ALOXE3 promoter, detrimentally impacting its activation. The consequential partial neutralization of ferroptosis induced by TRIB3 deficiency is observed through the implementation of ALOXE3 knockdown. Furthermore, the study demonstrated that the molecular inhibitor hesperidin, targeting TRIB3, not only reduced cell malignancy but also induced ferroptosis, thereby suppressing tumor growth. Overall, our findings unequivocally validate the proposition that TRIB3 deficiency precipitates the iron death mechanism, thereby indicating that the strategic targeting of TRIB3 could emerge as an innovative therapeutic strategy for HNSCC.

Background Concurrent chemoradiotherapy has been standard of care for unresectable esophageal carcinoma. There were no reports on proton radiotherapy (PRT) plus carbon-ion radiotherapy (CIRT) with pencil beam scanning (PBS) for esophageal carcinoma. This study evaluated the tolerability and efficiency of proton and sequential carbon-ion boost radiotherapy for esophageal carcinoma. Methods From April 2017 to July 2020, 20 patients with primary esophageal carcinoma at stages II–IV were treated with PRT plus sequential CIRT with PBS. A median relative biological effectiveness-weighted PRT dose of 50 Gy in 25 fractions, and a sequential CIRT dose of 21 Gy in 7 fractions were delivered. Respiratory motion management was used if the tumor moved > 5 mm during the breathing cycle. A dosimetric comparison of photon intensity-modulated radiotherapy (IMRT), PRT, and CIRT was performed. The median times and rates of survivals were estimated using the Kaplan–Meier method. Comparison of the dose-volume parameters of the organs at risk employed the Wilcoxon matched-pairs test. Results Twenty patients (15 men and 5 women, median age 70 years) were included in the analysis. With a median follow-up period of 25.0 months, the 2-year overall survival and progression-free survival rates were 69.2% and 57.4%, respectively. The patients tolerated radiotherapy and chemotherapy well. Grades 1, 2, 3, and 4 acute hematological toxicities were detected in 25%, 30%, 10%, and 30% of patients, respectively. Grades 3–5 acute non-hematological toxicities were not observed. Late toxicity events included grades 1, 2, and 3 in 50%, 20%, and 10% (pulmonary and esophageal toxicity in each) of patients. Grades 4–5 late toxicities were not noted. PRT or CIRT produced lower doses to organs at risk than did photon IMRT, especially the maximum dose delivered to the spinal cord and the mean doses delivered to the lungs and heart. Conclusions PRT plus CIRT with PBS appears to be a safe and effective treatment for esophageal carcinoma. PRT and CIRT delivered lower doses to organs at risk than did photon IMRT. Further investigation is warranted.

As medical facilities are usually built at urban areas, special concrete aggregates and evaluation methods are needed to optimize the design of concrete walls by balancing density, thickness, material composition, cost, and other factors. Carbon treatment rooms require a high radiation shielding requirement, as the neutron yield from carbon therapy is much higher than the neutron yield of protons. In this case study, the maximum carbon energy is 430 MeV/u and the maximum current is 0.27 nA from a hybrid particle therapy system. Hospital or facility construction should consider this requirement to design a special heavy concrete. In this work, magnetite is adopted as the major aggregate. Density is determined mainly by the major aggregate content of magnetite, and a heavy concrete test block was constructed for structural tests. The compressive strength is 35.7 MPa. The density ranges from 3.65 g/cm3 to 4.14 g/cm3, and the iron mass content ranges from 53.78% to 60.38% from the 12 cored sample measurements. It was found that there is a linear relationship between density and iron content, and mixing impurities should be the major reason leading to the nonuniform element and density distribution. The effect of this nonuniformity on radiation shielding properties for a carbon treatment room is investigated by three groups of Monte Carlo simulations. Higher density dominates to reduce shielding thickness. However, a higher content of high-Z elements will weaken the shielding strength, especially at a lower dose rate threshold and vice versa. The weakened side effect of a high iron content on the shielding property is obvious at 2.5 μSv/h. Therefore, we should not blindly pursue high Z content in engineering. If the thickness is constrained to 2 m, then the density can be reduced to 3.3 g/cm3, which will save cost by reducing the magnetite composition with 50.44% iron content. If a higher density of 3.9 g/cm3 with 57.65% iron content is selected for construction, then the thickness of the wall can be reduced to 174.2 cm, which will save space for equipment installation.

Purpose To investigate the efficacy and safety of particle beam radiotherapy (PBRT) in the management of patients with WHO grade 2 and 3 meningiomas. Methods Thirty-six consecutive and non-selected patients with WHO grade 2 (n = 28) and grade 3 (n = 8) meningiomas were treated at the Shanghai Proton and Heavy Ion Center, from May 2015 to March 2022. The median age of the cohort at PBRT was 48 years. There were 25 and 11 patients treated with PBRT in the setting of newly diagnosed diseases and progressive/recurrent diseases, respectively. PBRT was utilized as re-irradiation in 5 patients. Proton radiotherapy (PRT) and carbon-ion radiotherapy (CIRT), with a median dose of 60 Gy-Equivalent (GyE), were provided to 30 and 6 patients, respectively. Results With a median follow-up of 23.3 months, the local control rates were 92.0%, 82.0%, and 82.0% at 1, 2, and 3 years for the entire cohort, respectively. Patients with WHO grade 2 meningiomas (100%, 94.1%, 94,1% at 1,2,3 years) had a much better local control than those with WHO grade 3 meningiomas (50%, 25%, 25% at 1,2,3 years; P < 0.001). Three patients, all with WHO grade 3 meningiomas, had deceased at the time of this analysis. Multivariate analyses revealed that WHO grade (grade 2 vs. 3) (p = 0.016) was a significant prognosticator for local control. No severe toxicities (G3 or above) were observed. Conclusions Treatment-induced efficacy and toxicities to PBRT in WHO grade 2 and 3 meningiomas were both highly acceptable. Longer follow-up is needed to evaluate the long-term outcome in terms of disease control, survival, as well as potential late effects.

The recently described role of RNA methylation in regulating immune cell infiltration into tumors has attracted interest, given its potential impact on immunotherapy response. YTHDF1 is a versatile and powerful m6A reader, but the understanding of its impact on immune evasion is limited. Here, we reveal that tumor-intrinsic YTHDF1 drives immune evasion and immune checkpoint inhibitor (ICI) resistance. Additionally, YTHDF1 deficiency converts cold tumors into responsive hot tumors, which improves ICI efficacy. Mechanistically, YTHDF1 deficiency inhibits the translation of lysosomal genes and limits lysosomal proteolysis of the major histocompatibility complex class I (MHC-I) and antigens, ultimately restoring tumor immune surveillance. In addition, we design a system for exosome-mediated CRISPR/Cas9 delivery to target YTHDF1 in vivo, resulting in YTHDF1 depletion and antitumor activity. Our findings elucidate the role of tumor-intrinsic YTHDF1 in driving immune evasion and its underlying mechanism.

Additional file 1. The clinical information of LGG patients obtained from TCGA, CGGA, and GEO database.

Photon-based radiotherapy upregulates Notch signaling in cancer, leading to the acquisition of the stem cell phenotype and induction of invasion/migration, which contributes to the development of resistance to therapy. However, the effect of carbon ion radiotherapy (CIRT) on Notch signaling in glioma and its impact on stemness and migration is not explored yet. Human glioma cell lines (LN229 and U251), stable Notch1 intracellular domain (N1ICD) overexpressing phenotype of LN229 cells, and Notch inhibitor resistant LN229 cells (LN229R) were irradiated with either photon (X-rays) or (carbon ion irradiation) CII, and expressions of Notch signaling components were accessed by RT-PCR, Western blotting, and enzymatic assays and flow cytometry. Spheroid forming ability, cell migration, and clonogenic assay were used to evaluate the effect of modulated Notch signaling by irradiation. Our results show that X-ray irradiation induced the expression of Notch signaling components such as Notch receptors, target genes, and ADAM17 activity, while CII reduced it in glioma cell lines. The differential modulation of ADAM17 activity by CII and X-rays affected the cell surface levels of NOTCH1 and NOTCH2 receptors, as they were reduced by X-ray irradiation but increased in response to CII. Functionally, CII reduced the spheroid formation and migration of glioma cells, possibly by downregulating the N1ICD, as stable overexpression of N1ICD rescued these inhibitory effects of CII. Moreover, LN229R that are less reliant on Notch signaling for their survival showed less response to CII. Therefore, downregulation of Notch signaling resulting in the suppression of stemness and impaired cell migration by CII seen here may reduce tumor regrowth and disease dissemination, in addition to the well-established cytotoxic effects.

Background:To present and analyze the current status of registered clinical trials on particle beam (including proton and carbon ion beam) radiation therapy (PBRT) for head and neck (H&N) malignancies, and to provide insights for future clinical research, we designed the cross-sectional analysis.Methods:We identified and analyzed all clinical trials of interest registered on ClinicalTrials.gov and PTCOG.ch until March 22, 2020.Results:We identified 57 registered clinical trials related to the use of proton therapy or carbon ion radiation therapy (CIRT) in H&N malignancies. There were 20, 27, and 5 trials focused on CIRT, proton therapy, and both ions, respectively. The eligible trials were registered between 2007 and 2020, mainly focused on adenoid cystic carcinoma (ACC), squamous cell carcinoma (SCC), sinonasal malignancies (SNM), skull base tumors, locally advanced, and recurrent tumors. The nature of 23 (40%) trials were not stated and could not be identified. A total of 25 (44%) registered trials were phase II, including randomized controlled trials (RCTs). There were 14 RCTs (7 phase II, 2 phase II/III, 2 phase III, 1 phase I/II, and 2 phase not applicable), and 25 studies including RCTs were registered before the first enrolment. There were 11 completed clinical trials among the eligible trials, including 7 with published trial-related results.Conclusions:Less than 10% of the countries with PBRT treatment facilities in operation have initiated clinical trials on H&N cancer. Furthermore, among all registered trials, less than 10% have been completed with results published. More clinical trials, especially high quality trials, are needed for optimizing and standardizing treatment techniques of PBRT for H&N malignancies.

As of December 31, 2020, there were 12 facilities located in Asia and Europe which were treating cancer patients with carbon ion radiotherapy (CIRT). Between June 1994 and December 2020, 37,548 patients were treated with CIRT worldwide. Fifteen of these patients were United States (U.S.) citizens. Using the Surveillance, Epidemiology, and End Results cancer statistics database, the Mayo Clinic in Rochester, MN has conservatively estimated that there are approximately 44,340 people diagnosed each year in the U.S. with malignancies that would benefit from treatment with CIRT. The absence of CIRT facilities in the U.S. not only limits access to CIRT for cancer care but also prevents inclusion of U.S. citizens in phase III clinical trials that will determine the comparative effectiveness and cost effectiveness of CIRT for a variety of malignancies for FDA approval and insurance coverage. Past and present phase III clinical trials have not been able to enroll U.S. citizens due to their unwillingness or inability to travel abroad for CIRT for an extended period. These barriers could be overcome with a limited number of CIRT facilities in the U.S.

Purpose According to the presence or absence of isocitrate dehydrogenase (IDH) mutation, the 2021 WHO classification system bisected diffuse gliomas into IDH-mutant tumors and IDH-wildtype tumors. This study was aimed to evaluate the outcomes of proton radiotherapy treating IDH-mutant diffuse gliomas. Patients and Methods Between May 2015 and May 2022, a total of 52 consecutive patients with IDH-mutant diffuse gliomas were treated at Shanghai Proton and Heavy Ion Center. Tumor histologies were 33 cases of astrocytoma and 19 cases of oligodendroglioma. Tumor classified by WHO grade 2, 3 and 4 were 22, 25, and 5 cases, respectively. All 22 patients with WHO grade 2 tumors and one patient with brain stem WHO grade 4 tumor were irradiated with 54GyE. The other 29 patients with WHO grade 3 and 4 tumors were irradiated with 60GyE. Temozolomide was recommended to all patients, and was eventually conducted in 50 patients. Results The median follow-up time was 21.7 months. The 12/24-month progression-free survival (PFS) and overall survival (OS) rates for the entire cohort were 97.6%/78.4% and 100%/91.0% group. Examined by both univariate and multivariate analysis, WHO grade of tumor were of the most significant impact for both PFS and OS. No severe acute toxicity (grade 3 or above) was found. In terms of late toxicity, grade 3 radio-necrosis was developed in one case of oligodendroglioma, WHO grade 3. Conclusion Proton radiotherapy produced a favorable outcome with acceptable adverse-effects in patients with IDH-mutant diffuse gliomas.

Abstract OBJECTIVES Tumor Treating Fields (TTFields) is increasingly provided to patients with WHO grade 4 gliomas following radiotherapy. Particle beam radiotherapy (PBRT) represents a novel promising radiation approach with improved therapeutic ratio. This study was aimed to report an early result of TTFields in combination with PBRT for treating WHO grade 4 gliomas based on a prospective phase 2 trial from Shanghai Proton and Heavy Ion Center. METHODS This phase 2 trial was designed as a single-arm study to test the outcome of PBRT plus TTFields. Six patients with newly diagnosed WHO grade 4 gliomas receiving surgery, PBRT, temozolomide, and TTFields, from August 2021 to May 2022, were enrolled and analyzed. Tumor histologies based on the WHO CNS5 classification system were IDH-wild glioblastoma (n=4), IDH-mutant astrocytoma (n=1), and H3G34-mutant diffuse hemispheric glioma (n=1). For PBRT, all patients were irradiated with a baseline standard dose of 60GyE/30 utilizing proton. Carbon-ion boost of 15GyE/3 for tumor residual was performed for one patient prior to proton radiation. TTFields treatment was recommended to start soon after PBRT. RESULTS With a median follow-up of 5.5 months, all patients were alive at the time of this analysis; one patient with left thalamic glioblastoma had tumor progression of distant failure outside the radiation field at 4 months after partial tumor resection. The median interval between PBRT and TTFields was 2 days (range 1-22 days). No patient had dermatitis during PBRT. No severe TTField-related skin toxicity (Grade 3 or above) was observed. Five patients (83.3%, 5/6) developed mild skin toxicities (Grade 1) during TTField treatments. CONCLUSIONS Starting TTField early following PBRT is feasible for treating WHO grade 4 gliomas, the overall side effects are mild. Prospective studies with further follow-up are warranted to identify the outcomes of PBRT in combination with TTField in terms of survival and side effects.

Background: Nasopharyngeal adenoid cystic carcinoma (NACC) is a distinct subgroup of adenoid cystic carcinoma (ACC) with limited surgical access but predilection of regional and distant metastasis. Although radiotherapy is an integral treatment for patients with NACC, photon-based radiotherapy yielded suboptimal local control. Because of its advantages in biology and physics properties, carbon-ion radiotherapy (CIRT) was attempted for the treatment of head and neck ACC; however, the use of CIRT specifically for NACC has not been investigated. Methods: Patients with NACC that received CIRT alone or a combination of CIRT and proton beam therapy (PBT) at the Shanghai Proton and Heavy Ion Center (SPHIC) between July 2016 and March 2019 were included in the analysis. Patients with newly diagnosed NACC received combined therapy of CIRT (as boost) and PBT, and those with recurrent disease received CIRT alone. Overall survival (OS), local progression-free survival (LPFS), regional progression-free survival (RPFS), and distant metastasis-free survival (DMFS) were calculated by Kaplan-Meier method. Results: A total of 22 patients were included in this analysis. Among those, 18 patients had newly diagnosed NACC (17 with locally advanced disease), and 4 had recurrent NACC including 2 failed previous irradiation. After a median follow-up of 30.9 months, the 2-year OS rate, PFS rate, LPFS rate, RPFS rate and DMFS rate were 100%, 84.8%, 94.4%, 100%, and 84.8%, respectively. Three patients experienced grade 3 mucositis or xerostomia. No late toxicity of grade ≥3 was observed. Conclusions: CIRT alone or in combination with PBT appeared to be a promising modality for the treatment of NACC and produced satisfactory local disease control and toxicity profile. Distant metastasis remained to be a substantial mode for treatment failure. Further follow-up is necessary to evaluate long-term survivals and late toxicity profile.