[Molecular detection and subtyping of Blastocystis sp. in pigs in Anhui Province]

OBJECTIVE

To investigate the prevalence and subtype distribution of Blastocystis sp. in pigs in Anhui Province.

METHODS

A total of 500 stool samples were collected from large-scale pig farms in Bozhou, Anqing, Chuzhou, Hefei, Fuyang, and Lu'an cities in Anhui Province from October to December 2015. Blastocystis was detected in pig stool samples using a PCR assay based on the small subunit ribosomal RNA (SSU rRNA) gene, and positive samples were subjected to sequencing and sequence analysis. Blastocystis subtypes were characterized in the online PubMLST database, and verified using phylogenetic tree created with the neighbor-joining algorithm in the Meta software.

RESULTS

The prevalence of Blastocystis infection was 43.2% (216/500) in pigs in 6 cities of Anhui Province, and all pig farms were tested positive for Blastocystis. There was a region-specific prevalence rate of Blastocystis (17.2% to 50.0%) (χ2 = 26.084, P < 0.01), and there was a significant difference in the prevalence of Blastocystis sp. among nursery pigs (39.6%), preweaned pigs (19.1%), and growing pigs (62.3%) (χ2 = 74.951, P < 0.01). Both online inquiry and phylogenetic analysis revealed ST1, ST3, and ST5 subtypes in pigs, with ST5 as the predominant subtype.

CONCLUSIONS

The prevalence of Blastocystis sp. is high in pigs in Anhui Province, with three zoonotic subtypes identified, including ST1, ST3, and ST5.

Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at sqrt[s_{NN}]=200 GeV

The polarization of Λ and Λ[over ¯] hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sqrt[s_{NN}]=200  GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p_{T} dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and p_{T} dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

The effects of palliative care on patients with different classes heart function: A pilot study

The aim of this study was to explore effects of palliative care (PC) on patients with different heart function. Patients with NYHA (New York Heart Association) class II, III, IV were divided into separate groups. The KCCQ (Kansas City Cardiomyopathy Questionnaire) and HADS (Hospital Anxiety and Depression Scale) scores were compared before and 3 months after PC intervention. After 3 months, compared with the control group, PC could further significantly improve the KCCQ, HADS-depression and -anxiety scores of patients in NYHA class IV (P < 0.05); PC could significantly improve the HADS-depression and -anxiety scores of patients with NYHA class III (P < 0.05), and had an improvement tendency on KCCQ score. The study revealed that PC can significantly improve anxiety and depression of patients with NYHA class III or IV, and significantly improve the quality of life of patients with NYHA class IV, but had no effects on patients with NYHA class II.

Manganese Transfer Hydrogenases Based on the Biotin-Streptavidin Technology

Artificial (transfer) hydrogenases have been developed for organic synthesis, but they rely on precious metals. Native hydrogenases use Earth-abundant metals, but these cannot be applied for organic synthesis due, in part, to their substrate specificity. Herein, we report the design and development of manganese transfer hydrogenases based on the biotin-streptavidin technology. By incorporating bio-mimetic Mn(I) complexes into the binding cavity of streptavidin, and through chemo-genetic optimization, we have obtained artificial enzymes that hydrogenate ketones with nearly quantitative yield and up to 98 % enantiomeric excess (ee). These enzymes exhibit broad substrate scope and high functional-group tolerance. According to QM/MM calculations and X-ray crystallography, the S112Y mutation, combined with the appropriate chemical structure of the Mn cofactor plays a critical role in the reactivity and enantioselectivity of the artificial metalloenzyme (ArMs). Our work highlights the potential of ArMs incorporating base-meal cofactors for enantioselective organic synthesis.

Overcoming Radio-Immunotherapy Treatment Resistance through ILT4 Blockade and Reversal of HFRT Induced CXCL1-CXCR2 Axis Activation and Tumor-Associated Macrophage Immunosuppression

PURPOSE/OBJECTIVE(S)

Immunotherapy combined with radiotherapy (iRT) has unlimited potential, but up to 60% of cancer patients do not benefit from it. Enhancing the anti-tumor immune stimulatory effect triggered by radiotherapy is the key to overcome iRT resistance. Immunoglobulin-like transcript (ILT) 4 is a potential immune checkpoint molecule, highly expressed in various tumor cells, but its role in radiotherapy is still unknown. This study confirmed the role and molecular mechanism of ILT4 in suppressing radiotherapy immunosuppressive microenvironment formation and promoting tumor radiotherapy resistance. We propose a new therapeutic strategy that block ILT4 to enhance the efficacy of radiotherapy, and cooperate with radiotherapy to reverse immunotherapy resistance.

MATERIALS/METHODS

Using multiplex immunohistochemistry, we analyzed ILT4 expression, tumor-associated macrophage (TAM) /T cell phenotype and quantity in tumor patient treated with SBRT. Using mice subcutaneous tumor models, Single-cell RNA sequencing and multiplex flowcytometry, we assessed the role of ILT4 inhibition and hyper-fractionated radiotherapy (HFRT) on preventing tumor growth and immune escape. The molecular signaling and cytokines regulated by ILT4 under HFRT were analyzed by transcriptome sequencing and further verified by molecular experiments. By establishing cancer cell/TAM co-culture system in vitro, using CXCL1 protein or CXCR2 inhibitor and macrophage/CD8+ T cell deletion antibody in vivo, we identified the downstream pathway and cytokine of ILT4 to enhancing HFRT -induced TAM immune response.

RESULTS

In the tumor specimens of NSCLC patients treated with SBRT, we found that high ILT4 expression predicted poor progression-free survival and more M2-TAM recruitment. Among the C57BL/6 mice model, ILT4 inhibition in cancer cells reduced HFRT mediated M2-TAMs accumulation, and to sustain activation and proliferation of CD8+ T cells, and eventually suppressed tumor progression. Mechanistically, RT promoted ILT4 expression, which subsequently induced NF-κB pathway activation and CXCL1 secretion to enhance M2-TAMs migration in vitro. Using CXCL1 protein or CXCR2 inhibitor administration, inferring that ILT4 promotes TAMs migration via NF-κB-CXCL1-CXCR2 axis. Consistently, depletion of TAMs blocked the T cell function impairment and radiotherapy resistance induced by ILT4 in vivo. Importantly, targeting ILT4 potentiated the effect of radiotherapy, overcomes radio-immunotherapy treatment resistance.

CONCLUSION

ILT4 mediates HFRT-induced M2-like TAMs recruitment and subsequently T cell response impairment by regulating NF-κB-CXCL1-CXCR2 axis. ILT4 is an attractive drug target for enhancing radiotherapy and overcomes radio-immunotherapy treatment resistance.

Metformin Antagonizes Radiotherapy-Induced Anti-Tumor Effects via Inhibition of cGAS-STING Pathway Mediated Immune Responses

PURPOSE/OBJECTIVE(S)

Radiotherapy induced anti-tumor effects depend on both direct tumor cell death caused by radiation and immune activation mediated by cGAS-STING pathway. Metformin (MTF), which could augment the tumoricidal efficiency of radiation, is indicated to be a radiosensitizer by basic research. However, several large prospective clinical trials proved otherwise. In present study, we intend to interrogate the effects of MTF on radiotherapy-induced anti-tumor immune responses and try to explain the inconsistent outcomings of radiotherapy combined with MTF in basic research and clinical practice.

MATERIALS/METHODS

To explore the effects of MTF on radiotherapy induced anti-tumor effects, tumor models were established using E0771, B16F10 and LLC cell lines in both immunocompetent and immunodeficient mice. To investigate the composition and function of immune cells in tumor microenvironments, single-cell transcriptome sequencing of CD45+ cells sorted from tumor microenvironments were carried out, and flow cytometry and multiple immunofluorescence analysis were then performed for validation. To reveal the possible mechanisms, tumor cells were subjected to radiotherapy in the presence or absence of MTF in vitro, and RNA-sequencing was then employed followed by subsequent validation with western blotting, real-time qPCR and flow cytometry.

RESULTS

We found that systematic administration of MTF could significantly inhibit radiotherapy-induced anti-tumor effects in immunocompetent mouse models. Single cell sequencing of CD45+ cells sorted from tumor microenvironments and further validation showed that administration of MTF dramatically attenuated the infiltration and cytotoxic capacity of CD8+ T cells after radiotherapy. cGAS-STING pathway in tumor cells was required for maximum efficiency of radiotherapy, while MTF curbed cGAS-STING pathway after radiotherapy in a dose-dependent pattern by enhancing autophagy and reducing cytoplasmic mitochondrial DNA accumulation, which contributed to compromised anti-tumor effects.

CONCLUSION

Our findings indicated that MTF could antagonize radiotherapy-mediated anti-tumor effects by inhibiting the activation of cGAS-STING pathway and subsequent immune responses, which may partially explain the unsatisfied outcomes of radiotherapy combined with MTF in clinical practices. Since the anti-tumor effects of radiotherapy rely not only on the tumor-killing efficiency of radiation but also on systematic immune responses, our findings suggest that cautions are needed when MTF is administrated with radiotherapy in clinical practice.

Efficacy of Postoperative Radiotherapy for Patients with New N2 Descriptors of Subclassification in Completely Resected Non-Small Cell Lung Cancer: A Real-World Study

PURPOSE/OBJECTIVE(S)

Patients with N2 non-small cell lung cancer (NSCLC) were heterogeneous groups and required further stratification. The International Society for the Study of Lung Cancer (IASLC) added new descriptors of three sub-stages for stage N2 NSCLC: N2 at a single station without N1 involvement (N2a1), N2 at a single station with N1 involvement (N2a2), and N2 at multiple stations (N2b). This study aimed to investigate the efficacy of postoperative radiotherapy (PORT) for patients with these N2 descriptors.

MATERIALS/METHODS

Patients with histologically confirmed NSCLC after complete resection and divided into PORT group and non-PORT group. The primary endpoint was DFS. The second endpoints were overall survival (OS) and locoregional recurrence-free survival (LRFS). Propensity-score matching (PSM) of baseline characteristics between the PORT and non-PORT groups was used for validation.

RESULTS

Totally 1832 patients were enrolled, including 308 N2a1 patients, 682 N2a2 patients, and 842 N2b patients. The median follow-up time was 50.1 months. The survival outcomes of the PORT and non-PORT groups before PSM were shown in Table 1. For patients with N2a1, PORT could not improve the DFS (median DFS of the PORT group and the non-PORT group: not reached vs. 46.8 months, P = 0.41), OS (P = 0.85), or LRFS (P = 0.32), which were consistent with the multivariate analysis and data after the PSM. For patients with N2a2, PORT significantly improved the DFS (median DFS 29.7 vs. 22.2 months, P = 0.02), OS (P = 0.03), and LRFS (P = 0.01). The multivariate analysis and data after the PSM confirmed the benefits in DFS and LRFS, but no benefit was observed in OS (multivariate analysis: HR 0.79, P = 0.18; median OS after PSM: 103.7 vs. 63.1 months, P = 0.34). For patients with N2b, PORT could not improve the DFS (median DFS 20.6 vs. 21.2 months, P = 0.39) but significantly improved the OS (P<0.001) and LRFS (P<0.001). However, the multivariate analysis showed that PORT significantly improved DFS (HR 0.81, P = 0.03), consistent with the data after the PSM (median DFS 20.6 and 17.6 months, P = 0.04).

CONCLUSION

PORT significantly improved the DFS and LRFS in patients with N2a2 and significantly improved the DFS, LRFS, and OS in patients with N2b. Patients with N2a1 could not benefit from PORT.

Targeting XPO1 Combined with Radiotherapy to Enhance Systemic Anti-tumor Effects in Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

The combination of radiation and radiosensitizing chemotherapeutic agents have shown promising anti-tumor effects in NSCLC. Acting as an oncogenic driver, XPO1 is frequently overexpressed and/or mutated in lung cancer. Thus, suppression of XPO1-mediated nuclear export presents a unique therapeutic strategy. We hypothesize that XPO1 inhibition combined with radiotherapy (XRT) may remodel the tumor immune microenvironment (TIME) and reduce radioresistance, thus enhance systemic anti-tumor effects.

MATERIALS/METHODS

Herein, we optimized a small molecule inhibitor, WJ01024, which can bind to XPO1 and antagonize its activity to inhibit nuclear export. In the C57BL/6 mouse subcutaneous tumor model, we evaluated the ability of different treatment regimens containing oral WJ01014 single or combined with XRT (one fractions of 15 Gy) in tumor control and tumor recurrence inhibition. The effects of each treatment regimen on the alterations of immunophenotypes, including the quantification, activation, proliferative capacity, exhaustion marker expression, and memory status, were evaluated by flow cytometry.

RESULTS

In our study, we found that the overexpression of XPO1 was associated with poor prognosis and survival in radioresistant patients with NSCLC. The combination therapy of WJ01024 and XRT resulted in an increase of apoptosis and a decrease of proliferation compared to monotherapy, which was closely correlated with tumor regression and improved survival in the C57BL/6 mouse subcutaneous tumor model. Notably, we found that WJ01024 were shown to enhance the therapeutic effect of XRT by remodeling TIME. Compared with XRT, the addition of WJ01024 increased the infiltration and proliferation of radiation-stimulated CD8+ T cells, which especially promoted the production of interferon-γ and granzyme B. Moreover, the combination therapy also reversed the immunosuppressive effect of radiation on the percentage of Tregs and exhausted T cells in mouse xenografts. Thus, the TIME was significantly improved in combination therapy. Strikingly, mechanistic studies suggested that the activation of cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) signaling pathway is required to reshape TIME and produce synergistic anti-tumor effect with the combination of WJ01024 and XRT.

CONCLUSION

Our findings suggest that WJ01024 might be a potential synergistic treatment for radiotherapy to control the proliferation of NSCLC cells, promote tumor regression and prolong survival in mouse model of NSCLC by activating cGAS/STING signaling, and this in turn potentiate the immune microenvironment.

Single-Cell RNA Sequencing Reveals a Subset of cMAS can Aggravate RIHD through CXCL1-CXCR2 Axis

PURPOSE/OBJECTIVE(S)

Radiation induced heart disease (RIHD) is any form of cardiac toxicity induced by radiation therapy (RT) for thoracic cancers. Our previous studies have shown that RT obviously contributed to cardiovascular diseases-specific death over 3 years while RT became protective in the short term within 2 years survival in non-small cell lung cancer patients. Here, single cell RNA sequencing (scRNA-seq) was performed to identify various cell subsets and investigate their functions and dynamics in RIHD which offered several targets for early clinical interventions to alleviate RIHD.

MATERIALS/METHODS

Based on evaluation of histopathological characteristics, ejection fraction and serum levels of cardiac injury biomarkers, we have established mouse models during different stages to simulate clinical RIHD progression. Hence, we performed single cell RNA-sequencing of RIHD models to characterize the diversity within specific cell types and obtain basic information of differently expressed genes (DEGs). We investigated the role of several cell clusters and DEGs in RIHD through bioinformatics analysis and experimental verification. In vivo, mouse models were given intraperitoneal injection of CXCR2 inhibitor. Bone marrow macrophages and primary cardiac fibroblasts were extracted for in vitro experiments.

RESULTS

RIHD processes were divided into acute injury, compensation and decompensation stage. Transcriptomes of 31769 single cells from cardiac suspension have been profiled. Analysis of scRNA-seq revealed that there were 30 cell clusters participating in RIHD. The fraction of cell populations varied greatly at three stages which indicated RIHD was a dynamic process and each cell cluster functioned differently at different stages. Notably, we observed cardiac resident macrophages (cMAS) subset accounted for the highest fraction during the compensatory period and decreased in decompensation period. Pseudotime analysis showed cMAS had a different developmental trajectory compared to myeloid derived cells. Moreover, CXCR2 was significantly expressed in cMAS cluster. Ligand-receptor interaction results suggested that CXCL1 secreted by cardiac fibroblasts bind primarily to CXCR2+ cMAS and participated in the formation of the extracellular matrix (ECM) related to cardiac fibrosis. Moreover, cardiac fibrosis of RIHD models were relieved after CXCR2 inhibitor treatment. CXCL1 expression in primary cardiac fibroblast elevated after RT.

CONCLUSION

The identification of main cell clusters provided a new insight to investigate RIHD through dynamics of cell phenotypes and cell-cell communications during RIHD processes. In compensation stage, CXCR2+ cMAS could be activated by CXCL1 secreted by cardiac fibroblasts. Both were associated with ECM and contribute to the decompensation stage.

IL-1β+ Tumor Associated Macrophages Induced by Type I Interferon Initiates Radiotherapy-Mediated Abscopal Effect

PURPOSE/OBJECTIVE(S)

Both experimental and clinical studies have proved that radiotherapy can lead to not only local control of irradiated tumors, but also tumor regression of non-irradiated area, termed as abscopal effect. Abscopal effect has been attributed to radiotherapy-induced innate and adaptive anti-tumor immune responses. However, the detailed molecular mechanisms and key cellular components are still unclear. So, the purpose of this study is to reveal the key molecular mechanisms and essential cells in inducing abscopal effect.

MATERIALS/METHODS

Bilateral MC38 subcutaneous tumor mouse models were established, and primary tumors were subjected to one fraction of 15Gy. CD45+ cells were sorted from both primary and abscopal tumors 3-, 7-, 17- and 24-day post radiotherapy respectively and subjected to single-cell RNA sequencing followed by standard bioinformatic analysis with R studio. To verify the findings, flow cytometry, mIHC and real-time qPCR were carried out to analyze the cellular and molecular components in tumor microenvironments. Cellular depletion experiments and conditional knockout mice were finally employed to confirm key mechanisms that contribute to abscopal effect.

RESULTS

The primary and abscopal immune microenvironments showed different repertoires time-dependently. Radiotherapy induced durable type I interferon (IFN-I) responses with dramatic infiltration and activation of CD8+ T cells and tumor associated macrophages (TAMs) in primary tumors. However, in abscopal tumors, we found that TAMs rather than CD8+ T cells were the predominant population activated in early stages (3- and 7-day post radiotherapy), and functional CD8+ T cells enriched until late stages (24-day post radiotherapy). Thorough analysis of scRNA-seq and experimental validation discovered a unique subset of TAMs characterized by high expression of IL-1β emerged as early as 3-day post radiotherapy in both primary and secondary tumor immune microenvironments, termed as IL-1β+ TAMs herein. IL-1β+ TAMs were the main activated component in abscopal tumors in early stage, and strongest respondent to IFN-I pathway. Abscopal effect was significantly attenuated when IFN-I response was abolished in either primary or abscopal tumors or TAMs were depleted from abscopal tumors.

CONCLUSION

Our data identified a subset of immune cells, IL-1β+ TAMs, and IFN-I as the essential cellular and molecular components that contribute to abscopal effect. Mechanically, radiotherapy-induced dramatical IFN-I response in primary tumors lead to enrichment of IL-1β+ TAMs, which initiated the anti-tumor immune response in abscopal tumors. All these findings provided theoretical basis for understanding and improving radiotherapy-induced abscopal effect.

Spatial Proteome Analysis Identifies Lymphocyte CD44 as a Biomarker Associated with SBRT Resistance in Early-Stage Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

To discover and validate spatially-resolved protein markers associated with resistance to SBRT in early-stage NSCLC patients.

MATERIALS/METHODS

We initially evaluated a discovery cohort of 44 early-stage NSCLC patients treated with SBRT as first-line treatment at the Shandong cancer hospital. Using the GeoMx DSP system, 71 proteins were measured in five molecular compartments (tumor, leukocyte, lymphocyte, macrophage, and stroma) on pre-treatment samples. Candidate biomarkers were orthogonally validated with the Gem AQUA method of quantitative immunofluorescence (QIF). For internal independent cohort validation, we assessed pre-treatment samples derived from 150 NSCLC patients who receive radiotherapy. We further analyzed 100 radiotherapy untreated patients with operable NSCLC to address prognostic significance.

RESULTS

Using continuous log-scaled data, we identified CD44 expression in the lymphocyte compartment (CD3+) as a novel predictor of poor progression-free survival (PFS) (multivariate HR = 7.323, p = 0.0079) and overall survival (OS) (multivariate HR = 8.65, p = 0.028) in the discovery set. High CD44 expression in the tumor compartment (pan-cytokeratin, CK+) predicted significantly shorter OS (multivariate HR = 2.208, p = 0.0212), with no significant difference in PFS. We validated by QIF that lymphocyte CD44 levels were associated with resistance to SBRT therapy and prognostic for poor outcomes. Using QIF in an independent radiotherapy treated cohort, we validated that CD44 levels in the lymphocyte compartment were associated with poor PFS and OS. High lymphocyte cell CD44 was not prognostic in non-radiotherapy-treated cohort. Using DSP data, intratumoral regions with elevated lymphocyte cell CD44 expression showed prominent upregulation of CD127, ARG1 and VISTA in the discovery Cohort.

CONCLUSION

In conclusion, we identified and validated lymphocyte cell CD44 as a biomarker indicative of resistance to SBRT or radiotherapy in patients with NSCLC. Further evaluation is warranted to address the predictive value of lymphocyte cell CD44 in multi-institutional studies and clinical trials.

Irradiated Tumor Cells-Derived Exosomes Modulate Macrophage Polarization by Targeting SHP-2 Mediated Metabolic Reprogramming

PURPOSE/OBJECTIVE(S)

Tumor-associated macrophages (TAMs) constitute a plastic and heterogeneous cell population of the tumor microenvironment (TME) that can regulate tumor proliferation and support resistance to therapy, constituting promising targets for the development of novel anticancer agents. The efficacy of radiotherapy, a mainstay of cancer treatment, can strongly influence TAMs recruitment and phenotype. Our previous results demonstrated that SHP-2 and PD-L1 inhibition combined with radiotherapy enhances systemic antitumor effects in non-small cell lung cancer (NSCLC). Especially, SHP-2 has an important effect on the polarization of TAM in the context of radiotherapy. However, the immune mechanisms of SHP-2 in TAM remain largely unknown, and this leads us to implement this project.

MATERIALS/METHODS

Transmission electron microscopy and differential ultracentrifugation were used to verify the existence of exosomes. The bone marrow-derived macrophages (BMDM) and peritoneal macrophages (PM) were derived from C57BL/6 mice for vitro tests. In vivo and in vitro assays were used to identify roles of exosomal miRNA targeting SHP-2. To investigate the regulating function of SHP-2 in TAMs, co-culture experiments, qPCR, Western Blot, Flow Cytometry and Oxygraph-2k were employed. And we also explore tumor growth and tumor environment changes in SHP-2 flox/floxLyz-Cre+/- (CKO) mice.

RESULTS

We found that irradiated tumor cells-derived exosomes reprogramed their energy metabolism and polarized primary macrophages to an anti-inflammatory phenotype. Furthermore, SHP-2 in macrophages was a direct target of exosomal miR-138-5p from irradiated tumor cells. In vitro study also demonstrates that miR-138-5p can down-regulate SHP-2 in the BMDMs and PMs. Further research has shown that SHP-2 negatively regulated glycolysis through dephosphorylating Pyruvate kinase M2 (PKM2) at the Tyr105 site. In addition, SHP-2 can inhabit PKM2 translocation to the nucleus by dephosphorylating PKM2 at the Ser37 site. Thus, the SHP099 (a SHP-2 inhibitor) can uptake and utilization of glucose by SHP-2/PKM2(Tyr105) (Ser37)/β-catenin/LDHA/Glut-1 axis, suggesting that SHP099 plays positive roles on glycolysis and M1-polarized. In vivo study showed that SHP-2 flox/floxLyz-Cre+/- (CKO) mice display enhanced control of solid tumor growth, accompanied by increased the proportion of M1-like macrophages.

CONCLUSION

Our study demonstrates that exosomal miR-138-5p from irradiated tumor cells can modulate macrophage polarization by targeting SHP-2. And SHP-2 negatively regulates glycolysis and polarize macrophage to an M2 phenotype by SHP-2/PKM2(Tyr105) (Ser37)/β-catenin/LDHA/Glut-1 axis.

Carm1 Inhibition Potentiates Irradiation-Induced Antitumor Immunity via Tumor Intrinsic STING Pathway Activation

PURPOSE/OBJECTIVE(S)

Radiotherapy is commonly applied in multiple cancer types. Besides irradiation induced direct cell death, radiotherapy stimulated significant immune responses for tumor control. Intact and functional cGAS-STING pathway in both tumor cells and host cells is indispensable for efficient irradiation-induced anti-tumor effects. Coactivator-associated arginine methyltransferase 1 (Carm1) is emerging as an attractive therapeutic target and a biomarker for prognosis in various types of cancer. It has been reported that Carm1 inhibition could improve immunotherapy induced anti-tumor effects. However, it remains unclear how tumor cell intrinsic Carm1 affects irradiation-induced anti-tumor immunity.

MATERIALS/METHODS

Carm1 deficient cell lines were established in MC38 and B16F10 murine cancer cells using the CRISPR/Cas9 technology. To verify the effects of tumor `subcutaneous tumor mouse models were established and one fraction of 15Gy was administrated when the tumor volume reached 200mm3, followed by flow cytometry assays. Transcriptome sequencing, protein mass spectrometry, single-cell sequencing, Digital Spatial Profiling (DSP), real-time qPCR, western blotting, immunofluorescence and co-immunoprecipitation were carried out to explore and verify possible molecular mechanisms.

RESULTS

Here we found Carm1 deficiency in tumor cells dramatically enhanced irradiation-induced anti-tumor immune responses. Transcriptome sequencing of irradiated tumor cells and further experiments then validated that cGAS-STING pathway was significantly activated after irradiation in the absence of Carm1 in tumor cells, which contributed to enhance anti-tumor immunity after irradiation. Mechanistically, Carm1 deficiency in tumor cells attenuated autophagy, resulting in increased cytoplasmic mtDNA enrichment and enhanced cGAS-STING pathway activation. On the other hand, we also found that Carm1 caused asymmetric arginine methylation (ADMA) modification of TBK1 with reduced phosphorylation level, and Carm1 deficiency could activate cGAS-STING pathway by reducing AMDA modification and enhancing phosphorylation of TBK1. Finally, Carm1 inhibitor EZM2302 was applied in combination with radiotherapy in vitro, and it's indicated that combination therapy resulted in intensive anti-tumor immunity and prominent abscopal effects.

CONCLUSION

In this study, we identified that Carm1 ablation in tumor cells could promote irradiation-induced antitumor immunity through tumor cell intrinsic STING pathway activation. Mechanically, Carm1 deficiency directly activated the cGAS-STING pathway by interacting with TBK1 and increased mtDNA accumulation in cytoplasm by inhibiting autophagy. These findings provided new strategies for targeting Carm1 to boost the efficacy of radiotherapy.

RUNX1 as a Potential Target for Combined Radioimmunotherapy of Lung Adenocarcinoma

PURPOSE/OBJECTIVE(S)

Radioimmunotherapy for non-small cell lung cancer has good clinical application prospects. The role and mechanism of RUNX1 in DNA damage repair were explored for its potential role in lung adenocarcinoma radioimmunotherapy.

MATERIALS/METHODS

To study the effect of RUNX1 expression level on the expression of DNA damage repair system related factors and radiation sensitivity of lung adenocarcinoma cells. As an important nuclear transcription factor, RUNX1 was explored whether directly regulating the expression of Nrf2, Rad51, BRCA1, and verifying their respective DNA binding sites in the promoter region through relevant databases. To observe the effect of RUNX1 knockout and overexpression on the expression level of PD-L1 in tumor cells at the cell level; The effect of RUNX1 expression level on the sorting and presentation of PD-L1 cells was investigated by the method of nucleocytoplasmic separation. According to literature reports, CMTM6 and ALIX play a key role in the process of PD-L1 cell sorting and presentation, and explore whether RUNX1 plays a role through this factor. The effect of phosphorylation level of different splicing bodies of RUNX1 (RUNX1a/b/c) on the expression level and DNA damage repair system related factors on tumor radiosensitivity were also explored.

RESULTS

According to TCGA database, RUNX1 is highly expressed and phosphorylated in lung adenocarcinoma. Through gene comparison with the database, it was found that RUNX1 binding sites existed in the promoter region of several factors related to this study, including ALIX, Nrf2, BRCA1, RAD51, ATM, H2AX, etc. After being activated by MAPKp38 phosphorylation, RUNX1a can positively regulate Nrf2 signal pathway. The expression of RUNX1 and p-RUNX1 is time-dependent on ionizing radiation. At the same time, it was found that the expression of RUNX1 and p-RUNX1 was dose-dependent on ionizing radiation, and the expression trend of Nrf2 signal pathway related factors was consistent with RUNX1. RUNX1 regulates the expression of PD-L1, BRCA1, ALIX and Nrf2. Bioinformatics analysis and flow cytometry data show that RUNX1 has inhibitory effect on tumor microenvironment of lung adenocarcinoma.

CONCLUSION

RUNX1 regulates DNA damage repair system and has inhibitory effect on tumor immunity. Inhibiting the expression of RUNX1 in lung adenocarcinoma cells can enhance the effect of radioimmunotherapy.

Safety and Efficacy Analysis of Patients with Extensive-Stage Small Cell Lung Cancer (ES-SCLC) Treated with SHR-1316 Plus Chemotherapy and Sequential Chest Radiotherapy as First-Line Therapy from a Phase II Trial

PURPOSE/OBJECTIVE(S)

CAPSTONE-1, a phase 3 trial, showed that SHR-1316 (PD-L1 antibody) combined with standard first-line chemotherapy could prolong overall survival (OS) in patients (pts) with ES-SCLC. The CREST trial reported consolidative thoracic radiotherapy (TRT) of 30 Gy in 10 fractions provided a 10% 2-year OS benefit and more intensive TRT should be investigated in ES-SCLC. In the era of immunotherapy, the role of TRT also needs further exploration. Therefore, we designed this clinical trial to investigate the efficacy and safety of SHR-1316 plus first-line chemotherapy followed by TRT combined with SHR-1316.

MATERIALS/METHODS

Key inclusion criteria were pts aged 18-75 years, with previously untreated histologically or cytologically confirmed ES-SCLC, and an ECOG performance status of 0-1. Eligible pts would receive 4∼6 cycles of SHR-1316 (20mg/kg, D1, q3w) combined with EP/EC (etoposide, 100mg/m2, D1-5, q3w and cisplatin, 75mg/m², D1-3, q3w or carboplatin, AUC = 5, D1, q3w), followed by SHR-1316 combined with TRT (≥3 Gy*10 f or ≥2 Gy*25 f, involved-field irradiation), and then the maintenance therapy with SHR-1316 until disease progression or intolerable adverse events (AEs). The main endpoints included ORR, PFS and safety.

RESULTS

From October 2020 to January 2023, 33 pts received SHR-1316 and sequential consolidative TRT. Among them, 19 pts received high-dose TRT (>3 Gy*10 f or ≥2 Gy*25 f) and 14 pts received low-dose TRT (≤3 Gy*10 f or<2 Gy*25 f). The median age was 62 (range: 38-73). Most pts were male (28, 84.8%), former smokers (22, 66.7%) with an ECOG performance status 1 (32, 97%). Ten (30.3%) pts were diagnosed with brain metastasis and 10 (30.3%) pts had liver metastasis at baseline. At the data cutoff date, 9 pts remained on treatment, the average number of treatment cycles was 9.2. 33 pts had at least one 1 post-treatment tumor assessment. The confirmed ORR and DCR were 90.9% (30/33) and 100% (33/33) in all pts, were 89.5% (17/19) and 100% (19/19) in high-dose TRT group, and were 92.9% (13/14) and 100% (14/14) in low-dose TRT group. The median PFS was 10.2(CI: 5.8∼14.7) months in all pts, was 7 (CI: 3.8∼10.2) months in high-dose TRT group and 10.4 (CI: 8.4∼12.3) months in low-dose TRT group. AEs occurred in 27 (81.8%) pts and grade 3 or 4 AEs occurred in 20 (60.6%) pts. The most common grade 3 or 4 AEs included neutropenia (15, 45.5%), leukopenia (8, 24.2%), lymphocytopenia (5, 15.2%), pneumonia (3, 9.1%), anemia (3, 9.1%) and thrombocytopenia (2, 6.1%).

CONCLUSION

SHR-1316 plus chemotherapy and sequential TRT as first-line therapy for ES-SCLC showed promising efficacy and acceptable safety. There is no significant difference between high-dose and low-dose TRT groups in terms of safety and efficacy according to current data.

Role and Modality of Combining Radiotherapy with Immunotherapy in Stage III-IV Unresectable Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

The combination of radiotherapy and immunotherapy was rarely reported in the management of small cell lung cancer (SCLC). We retrospectively assessed the role and modality of this combination in Stage III-IV unresectable SCLC.

MATERIALS/METHODS

Patients with stage III and IV SCLC were enrolled according to AJCC 8th edition. Both efficacy and safety of immunotherapy combined with radiotherapy were evaluated. Thereinto, patients received first-line chemo-immunotherapy and sequential thoracic consolidation radiotherapy (TCRT) were further evaluated. Survival and descriptive analyses were performed.

RESULTS

Between January 1, 2019 and December 31, 2021, 51 patients were included in our analysis. Median follow-up was 28.0 months (95% CI 22.8-33.2). Patients received radiotherapy in treatment course had a prolonged 2-year overall survival (OS). And in the first-line immunotherapy cohort of 27 patients, the addition of TCRT significantly improved 2y-OS (72.22% vs. 13.89%, p = 0.0048), 2y-locoregional recurrence free survival (LRRFS) (90.00% vs 48.00%, p = 0.011), and 2y-distance progression free survival (DPFS) (66.67% vs. 16.67%, p = 0.039). Subgroup analyses showed that TCRT rendered superior outcomes regardless of brain metastases. Dose-escalation (45 Gy/15f) and earlier radiotherapy seemed to improve the benefit. Of 70.37% (19/27) patients experienced disease progression in the TCRT evaluation cohort, 63.16% (12/19) patients failed in brain. A tendency toward better OS and superior brain metastases free survival (BMFS) were observed after receiving prophylactic cranial irradiation (PCI). Finally, the most common grade 2 or higher toxic effects were pneumonitis in all patients (11.76% of immune-related vs. 7.84% of radiation related).

CONCLUSION

Earlier addition of TCRT to immunotherapy could significantly improve survival and extracranial control for stage IIIA-IVB unresectable SCLC patients, with no increased risk of adverse events. In the era of immunotherapy, PCI may still be a recommended strategy. Further investigation is warranted.

HPK1 Inhibition Enhancing HFRT Anti-Tumor Immune Response

PURPOSE/OBJECTIVE(S)

Radiation therapy, as one of the canonical treatments for classic tumors, results in impressive clinical responses. Stereotactic body radiotherapy (SBRT) has been increasingly used as one main therapy in early-stage non-small-cell lung cancer (NSCLC). SBRT affords good local tumor control, however, recurrence and metastasis are still the main causes of treatment failure. With the continuous deepening of the relationship between radiotherapy (RT) and immunity, reversing RT induced immunosuppression is considered to be a promising strategy to improve radiotherapy efficacy. Hematopoietic progenitor kinase 1 (HPK1) is mainly expressed in immune cells while rarely expressed in tumor cells. It has been proven to play a negative regulatory role in T cell receptor (TCR) signal. Therefore, we hypothesized that the combination of HPK1 inhibitor with SBRT would boost local and systemic anti-tumor immune responses by potentiating the anti-tumor effects of SBRT.

MATERIALS/METHODS

Using Digital Spatial Profiler (DSP), we analyzed HPK1 expression in the tumor specimens of 39 NSCLC patients treated with SBRT. By establishing mice subcutaneous tumor models, we assessed the combination of a HPK1 inhibitor and local hyper-fractionated radiotherapy (HFRT) on local and systemic tumor control and mouse survival. Using Single-cell RNA sequencing, Flow cytometry and pharmacological treatment, we analyzed and verified Tumor-infiltrating lymphocytes (TILs), and excavated the specific mechanism of the HPK1 inhibitor enhancing HFRT -induced anti -tumor immune response.

RESULTS

In the tumor specimens of NSCLC patients treated with SBRT, we found that high expression HPK1 in TILs predicted poor progression-free survival (PFS). Among the C57BL/6 mice model, HFRT combined with a HPK1 inhibitor promoted local response, and improved the survival rate of mice, showing better anti-tumor curative effects. We further showed that HFRT promoted CD8+ T cell cytotoxic activity, and also aggravated CD8+ T cell exhaustion. After the intervention of HPK1 small molecular inhibitors, the proportion of exhaustion CD8+T cells was significantly reduced, while CD8+T cell cytotoxic activity was further enhanced in the later period. Single-cell RNA sequencing and pharmacological inhibition of HPK1 revealed that HPK1 mediated the exhaustion of CD8+T cells by regulating RGS16. In abscopal effects preclinical models, BGB-15025 induced obvious abscopal effect.

CONCLUSION

Thus, we demonstrate that HPK1 mediates HFRT-induced CD8+T cell exhaustion by regulating RGS16, and HPK1 is an attractive drug target for enhancing local and systemic radiotherapy.

Dosimetric Analysis of Proton Beam Therapy vs. Photon Radiotherapy for Cardiac Tumors with or without Deep Inspiratory Breath Holding: A Case Report

PURPOSE/OBJECTIVE(S)

Proton beam therapy (PBT) has been demonstrated to deliver equivalent dosimetric radiation with the benefit of improved sparing of organs at risk (OAR). Deep inspiration breath holding (DIBH) is a commonly used method for reducing the radiation dose to the heart and lungs. However, few studies have ever reported the usage of DIBH combined with proton beam therapy in cardiac tumors. The purpose of this case report is to compare the dosimetric differences between photon radiotherapy and proton radiation therapy (PBT) with or without deep inspiration breath holding.

MATERIALS/METHODS

A 66-year-old female patient with cardiac tumors was recruited, and the prescribed dose of radiotherapy for cardiac tumors was 95%PGTV 50Gy/2.5Gy/20f. Two simulation CT scans were collected during free breath (FB) and DIBH. And the target area was delineated on deep inspiratory breath holding image (DIBH-CT) and free breathing image (FB-CT). The target area of FB-CT was modified by referring to the ten-time phases of 4D-CT. Finally, IMRT, VMAT and PBT plans (DIBH-IMRT, DIBH-VAMT, DIBH-PBT, FB-IMRT, FB-VAMT, FB-PBT) were generated on the above images, and the organs at risk were limited as follows: lungs V20 ≤20%, lungs mean ≤11 Gy, heart V30 ≤40%, coronary artery mean ≤26 Gy, spinal cord ≤30 Gy, and left breast mean ≤5 Gy.

RESULTS

All of the six plans satisfied most of the treatment planning goals. DIBH resulted in a dose reduction in all organs at risk including the heart, lungs, coronary artery (CA), spinal cord and breasts, when compared with FB using IMRT, VMAT, or PBT. Compared with the FB, DIBH provided a significant reduction in the mean dose of coronary artery (CA mean for DIBH-IMRT vs FB-IMRT = 28.32 Gy vs 42.66 Gy, CA mean for DIBH-VMAT vs FB-VAMT = 26.44Gy vs 40.85Gy, CA mean for DIBH-PBT vs FB-PBT = 27.71Gy vs 39.51Gy). Similarly, when compared with IMRT or VMAT in either FB or DIBH, PBT reduced radiation doses for all of the OAR. In comparison, the difference was less significant between IMRT and VMAT technique. Pitmen compared with IMRT and VMAT, reduced significantly the max dose of spinal cord, lungs V5, breast-L/R mean. Totally, DIBH-PBT was observed sufficient dose coverage and better sparing of organs at risk.

CONCLUSION

PBT combined with DIBH technique gained an advantage in the sparing of OAR for cardiac tumors, especially in coronary protection. The possibility of broader application of PBT with DIBH in clinical practice is currently being evaluated and further studies are needed.

IKBKE Promotes Radioresistance of Glioblastoma through AKT/FOXO3a Pathway

PURPOSE/OBJECTIVE(S)

Glioblastoma is an intracranial highly malignant primary tumor, and postoperative radiotherapy is a common treatment of glioblastoma. While radiotherapy resistance of glioblastoma is an important reason for treatment failure. IKBKE is overexpressed in gliomas, but its role in radiotherapy is unknown. This study confirmed that IKBKE can directly phosphorylate AKT protein to regulate FOXO3a, thus promoting the radioresistance of glioblastoma, and proposed a new therapeutic strategy to enhance the efficacy of radiotherapy.

MATERIALS/METHODS

We used flow cytometry, tunel staining, plate cloning, a cell counting kit and WB to confirm the effects of IKBKE and FOXO3a on radioresistance of glioblastoma, and immunofluorescence and WB were used to detect the expression of γ-H2AX. Subcutaneous tumor formation in mice and immunohistochemical staining was performed. IP combined with mass spectrometry, immunofluorescence, endogenous and exogenous IP were used to confirm the interaction between IKBKE and AKT. Point mutation, IP and WB were used to confirm the phosphorylation site of AKT. IP and some small molecule inhibitors were used to confirm the relationship between IKBKE, AKT and PI3K. The effect of IKBKE on FOXO3a was confirmed by WB and qPCR. The protein relationship among IKBKE, FOXO3a and 14-3-3 was confirmed by CHX, MG132, ubiquitin test, immunofluorescence and IP. The above experiments were carried out to verify the effect of Amlexanox, an IKBKE inhibitor, on glioblastoma. And its pharmacokinetics in the brain was determined by LC-MS to provide a theoretical basis for further clinical use.

RESULTS

It was found that IKBKE could increase the radioresistance of glioblastoma in vitro and in vivo. IKBKE could directly phosphorylate AKT, and its phosphorylation sites were Ser473 and Thr308. We also certified that IKBKE activated AKT independent of PI3K. IKBKE inhibited the expression of FOXO3a on protein level, promoted its ubiquitin degradation, enhanced its interaction with 14-3-3, and inhibited its transportation into the nucleus. FOXO3a can increase the radiosensitivity of glioblastoma. Amlexanox, an IKBKE inhibitor, can inhibit the radiosensitivity of glioblastoma and partially pass through the blood-brain barrier to enhance the radiosensitivity of intracranial tumors.

CONCLUSION

IKBKE can activate AKT independent of PI3K by directly phosphorylating AKT Ser473 and Thr308, thus increasing the phosphorylation of FOXO3a. Phosphorylated FOXO3a promoted its ubiquitin degradation, and inhibited its transportation into the nucleus, causing radioresistance in glioblastoma. IKBKE inhibitor Amlexanox can pass through the blood-brain barrier and increase the radiosensitivity of intracranial tumor cells.

Chemoradiotherapy Combined with Nab-Paclitaxel plus Cisplatin in Patients with Locally Advanced Borderline Resectable or Unresectable Esophageal Squamous Cell Carcinoma: A Phase I/II Study

PURPOSE/OBJECTIVE(S)

To evaluate the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-PTX) plus cisplatin as the regimen of conversional chemoradiotherapy (cCRT) in locally advanced borderline resectable or unresectable esophageal squamous cell carcinoma (ESCC).

MATERIALS/METHODS

Patients with locally advanced ESCC (cT3-4, Nany, M0-1, M1 was limited to lymph node metastasis in the supraclavicular area) were enrolled. All the patients received the cCRT of nab-PTX plus cisplatin. After the cCRT, those resectable patients received esophagectomy; those unresectable patients continued to receive the definitive chemoradiotherapy (dCRT). The locoregional control (LRC), overall survival (OS), progression-free survival (PFS), distant metastasis free survival (DMFS), pathological complete response (pCR), R0 resection rate and adverse events (AEs) were calculated.

RESULTS

A total of 45 patients with ESCC treated from October 2019 to May 2021 were finally included. The median follow-up time was 30.3 months. The LRC, OS, EFS, DMFS at 1and 2 years were 81.5%, 86.6%, 64.3%, 73.2% and 72.4%, 68.8%, 44.8%, 52.7% respectively. 21 patients (46.7%) received conversional chemoradiotherapy plus surgery (cCRT+S). The pCR rate and R0 resection rate were 47.6% and 84.0%. The LRC rate at 1 and 2 years were 95.0%, 87.1% in cCRT+S patients and 69.3%, 58.7% in dCRT patients respectively (HR, 5.14; 95% CI, 1.10-23.94; P = 0.021). The OS rate at 1 and 2 years were 95.2% and 84.2% in resectable patients compared to 78.8% and 54.4% in unresectable patients (HR, 3.41; 95% CI, 1.10-10.61; P = 0.024). The toxicities during chemoradiotherapy were tolerated, the most common grade 3-4 toxicities were radiation esophagitis (15.6%).

CONCLUSION

Nab-PTX plus cisplatin were effective and safe as the regimen of conversional chemoradiotherapy of ESCC. The patients receiving conversional chemoradiotherapy plus surgery (cCRT+S) were prone to have a better survival.

The Baseline Serum Lipid Levels and Outcomes of NSCLC Patients Receiving Immunotherapy Combined or Non-Combined with Radiotherapy: A Single Center Retrospective Study

PURPOSE/OBJECTIVE(S)

In recent years, many studies have shown that lipids and lipid-like substances are key regulatory factors in tumor development and play an important role in immune regulation. However, it remains unclear whether serum lipids influence the outcome of immunotherapy. Therefore, determining the serum lipid levels of the immune treatment-beneficiary population may be valuable. The aim of this study is to evaluate the prognostic value of baseline serum lipid levels in non-small cell lung cancer (NSCLC) patients receiving immunotherapy.

MATERIALS/METHODS

We retrospectively included 294 patients with stage III-IV NSCLC who received immunotherapy continuously from December 2018 to November 2021 at our hospital, collecting their pre-treatment lipid levels, such as total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). Of these, 160 receiving immunotherapy without combined radiotherapy (ICIs-nRT) and 134 combined with radiotherapy (iRT). The endpoint was the correlation between pre-treatment serum lipid levels and overall survival (OS), as well as progression-free survival (PFS). The X-tile tool was used to determine the optimal cut-off value of the indicators. The Kaplan-Meier survival curves were used to calculate OS and PFS and log rank tests were used for comparison. And the Cox proportional hazard model were used for univariate and multivariate analysis.

RESULTS

In all 294 patients, low TG, low TC, and low HDL-C predicted poor OS (P<0.001) and poor PFS (P<0.05). Low LDL-C was associated with poor OS (P = 0.0001). Among 160 patients receiving ICIs-nRT and 134 iRT patients, low levels of TG (P = 0.0134, 0.0024), TC (P = 0.0003, 0.0023), HDL-C (P = 0.0004, 0.0043), and LDL-C (P = 0.0003, 0.0419) were associated with worse OS compared to high levels of them. In the ICIs-nRT patients, low HDL-C predicted poor PFS (P = 0.0011). In 134 iRT patients, low levels of TG (P = 0.0017), TC (P = 0.0028), and LDL-C (P = 0.0330) were poor prognostic factors for PFS. In the univariate and multivariate analysis with OS in all patients, TG and HDL-C were independent risk factors, while TG was an independent risk factor in the analysis with PFS. In ICIs-nRT patients, HDL-C was an independent prognostic factor for patients' OS and PFS. In iRT patients, both TG and HDL-C were prognostic risk factors for OS.

CONCLUSION

These data confirm that higher serum lipid levels are associated with better outcomes in patients with NSCLC undergoing immunotherapy. Serum lipids may identify tumors that are more likely to respond to immunotherapy. Radiation therapy may affect lipid metabolism within the body to enhance the efficacy of immunotherapy.

The Updated Landscape of Tumor Microenvironment and Pre-Metastasis Niches for Radiotherapy Resistant Tumors

PURPOSE/OBJECTIVE(S)

In the current clinical work, hypo-fractionated radiotherapy (HFRT) and conventional fractionated radiotherapy (CFRT) are considered to be completely different treatments. However, the difference between the HFRT and CFRT in reprogramming the tumor immune microenvironment (TIME) is still inconclusive. Our previous work found that compared with HFRT, CFRT is more inclined to trigger immunosuppressive phenotype, but the underlying mechanism is still unclear. Based on this, we use single-cell mRNA sequencing to describe the landscape of TIME with HFRT and CFRT, and find the key targets or pathways to combine with radiotherapy.

MATERIALS/METHODS

By simulating the in vivo radiotherapy strategy, we built recurrent murine cell lines mimicking CFRT and HFRT recurrent tumors (CFRT_R and HFRT_R tumors) with small animal radiation research platform (SARRP).

RESULTS

Based on this unique model, we found that CFRT_R tumors can promote local relapse and lung metastasis significantly compared to HFRT_R tumors. Results of single-cell mRNA sequencing and FCAS also indicate that CFRT_R tumors possess more macrophages in the tumor site and neutrophils in the metastatic site. By using quantitative proteomics of secreted proteins, we prove that CFRT_R tumors secret more Ccl2, S100a11 and Slpi. Mechanically, CFRT_R tumors influence the polarization of M2 TAMs leading to tumor growth through secretion of Ccl2 and S100a11. Meanwhile, CFRT_R tumors also augment the infiltration of neutrophils in the lung through Slpi altering the lung immune landscape to support metastasis. ChIP and EMSA results also reveal that RelB is the core transcription factor of Ccl2, S100a11 and Slpi. Furthermore, local relapse and lung metastasis can be reversed by targeting non-canonical NF-kB pathway.

CONCLUSION

The effect of CFRT_R and HFRT_R tumors in reprogramming TIME is different, CFRT_R tumors can trigger immunosuppressive phenotype compared to HFRT_R tumors by possessing more M2 TAMs in the tumor site and neutrophils in the metastatic site. The killing function of tumor infiltrated T cells can be inhibited by accumulated M2 TAMs, and abundant neutrophils in lungs contribute to the formation of the pre-metastatic niche. Targeting non-canonical NF-kB pathway can reverse local relapse and lung metastasis in CFRT_R tumors by suppressing Ccl2, S100a11 and Slpi secretion. In short, our study not only deepens the understanding of the immune landscape of CFRT and HFRT recurrence tumors, but also provides a novel therapy of CFRT recurrence patients.

A Dosimetric Study Indicates the Spinal Cord Irradiation Contributes to Acute Hematologic Toxicities in Non-Small Cell Lung Cancer Patients Receiving Radiotherapy Combined with Immunotherapy

PURPOSE/OBJECTIVE(S)

To assess the radiation therapy (RT) dose to radiation-associated hematologic toxicities (HTs) in patients with non-small cell lung cancer (NSCLC) after RT combined with immunotherapy.

MATERIALS/METHODS

Cases of NSCLC treated with RT combined with immunotherapy at Shandong Cancer Hospital in China were identified. The mean dose and the volume of the spinal cord receiving at least 5 to 40 Gy (V5-V40) were retrospectively recorded. Logistic regression was used to estimate associations between grade ≥3 HT (HT3+) and dosimetric/clinical parameters. Receiver operating characteristic analysis was used to determine dosimetric cut-points.

RESULTS

Ninety-nine patients were analyzed. The majority were male (n = 78, 78.8%) and received chemotherapy (n = 83, 83.9%). All patients received either anti-PD-1 immune checkpoint (n = 89, 89.9%) or anti-PD-L1 immune checkpoint (n = 10, 10.1%) therapy. The rate of HT3+ was 24.2% (n = 24). Spinal cord mean dose, V5 to V40 and BMI parameters associated with HT3+ were included in the multivariate analysis. On multivariate analysis, increasing mean spinal cord dose (per Gy) was associated with higher odds of developing HT3+ (odds ratio 1.053, 95% confidence interval 1.002-1.105, P = .041), as were increasing spinal cord V5 to V20 (As show in the Table below). The optimal cut-points identified were V5 = 52.5%, V10 = 47.5%, V20 = 39.4%, and mean dose = 23.3 Gy. Patients with values above these cut-points had an approximately 2-fold increased risk of HT3+.

CONCLUSION

We found that mean spinal cord dose and low-dose parameters (V5-V20) were associated with HT3+ in NSCLC patients after RT and immunotherapy. The mean dose of the spinal cord should be kept lower than 23.3 Gy for these patients. These data suggested that efforts to spare doses to the spinal cord might reduce rates of severe HT.

Focal Boosted IMRT Treatment of Prostate Cancer to 84 Gy in 28 Fractions: Preliminary Clinical Outcomes and Dosimetry

PURPOSE/OBJECTIVE(S)

The FLAME trial reported that focal boosting of prostate tumor to 95 Gy in 35 fractions improves biochemical control. However, this treatment is not commonly used in the United States. We investigated a focally boosted treatment of 84 Gy in 28 fractions (EQD2 108 Gy, BED 252 Gy).

MATERIALS/METHODS

Between 2019-2022, men with unfavorable intermediate risk (uIR) and high risk (HR) prostate cancer were enrolled on a prospective registry and received a novel IMRT regimen. The dose levels were 84 Gy to the gross tumor volume (GTV) as defined on mpMRI (T2W and ADC) with no added margin, 70 Gy to the prostate and proximal seminal vesicles, and optional 50.4 Gy to elective pelvic lymph nodes (all 28 fractions). Patients received fiducial markers and hydrogel spacer. The treatment planning goal was to cover 95% of the GTV at 84 Gy, and also meet the target and normal tissue dosimetry criteria of the hypofractionated treatment arm of NRG-GU005. VMAT was used for treatment delivery. ADT was given at the discretion of the treating physician.

RESULTS

A total of 20 men were included in the study, 2 (10%) uIR and 18 (90%) HR. 9 (45%) tumors were GS 7, 7 (35%) were GS 8, and 4 (20%) were GS 9. There were 13 (65%) stage cT1, 4 (20%) cT2 and 3 (15%) cT3. One (5%) patient received short term ADT, 18 (95%) long term ADT, and 1 (5%) refused ADT. 18 (90%) men received elective nodal radiation. The mean baseline PSA was 25.1 (range 4.2-73.4). The median baseline IPSS score was 11.1 (IQR 4.5-12), and 4 patients had severe baseline urinary symptoms (IPSS ≥20). The mean baseline prostate volume was 57.4 cc (range 26.8-198.3). The mean volume of the 84 Gy boost target was 7.1 cc (range 2.3-15.0) and the mean proportion of the prostate boosted was 14.8% (range 2% - 47%). There were 10 (50%) men with 1 boost target, 6 (30%) with two, 3 (15%) with three, and 1 (5%) had 4 boost targets. Targets were located in peripheral zone (85%), transition zone (30%), and central zone (5%). Patients met all per-protocol normal tissue criteria of NRG-GU005, except for bladder D0.03cc. The mean±SD (Gy) rectum D15%, D25%, and D30% were 51±5, 45±5, 42±4. The mean±SD (Gy) bladder D0.03cc, D30%, D50% were 79±4, 50±8, 38±10. At a median follow up time of 21.3 months (range 7.1-38.2), no patients have developed biochemical progression, local recurrence, distant progression, or death from prostate cancer. One patient died at 18 months from metastatic colorectal cancer, unrelated to prostate cancer treatment. Acute grade 1-2 GU toxicity occurred in 13 (65%) patients, and acute grade 1-2 GI toxicity occurred in 4 (20%) patients. No patients developed grade 3+ acute or late GU or GI toxicity. Two patients required temporary foley catheter for obstruction during RT, and both had IPSS >20 at baseline. The patient who refused ADT had a PSA bounce of magnitude 2.2 ng/mL at 14 months, PSA values declined without additional treatment.

CONCLUSION

A novel 28-fraction focal boosted IMRT treatment is feasible and has an acceptable early toxicity profile. Oncologic results are promising but require longer follow up.