Blocking the MIF-CD74 axis augments radiotherapy efficacy for brain metastasis in NSCLC via synergistically promoting microglia M1 polarization

BACKGROUND

Brain metastasis is one of the main causes of recurrence and death in non-small cell lung cancer (NSCLC). Although radiotherapy is the main local therapy for brain metastasis, it is inevitable that some cancer cells become resistant to radiation. Microglia, as macrophages colonized in the brain, play an important role in the tumor microenvironment. Radiotherapy could activate microglia to polarize into both the M1 and M2 phenotypes. Therefore, searching for crosstalk molecules within the microenvironment that can specifically regulate the polarization of microglia is a potential strategy for improving radiation resistance.

METHODS

We used databases to detect the expression of MIF in NSCLC and its relationship with prognosis. We analyzed the effects of targeted blockade of the MIF/CD74 axis on the polarization and function of microglia during radiotherapy using flow cytometry. The mouse model of brain metastasis was used to assess the effect of targeted blockade of MIF/CD74 axis on the growth of brain metastasis.

RESULT

Our findings reveals that the macrophage migration inhibitory factor (MIF) was highly expressed in NSCLC and is associated with the prognosis of NSCLC. Mechanistically, we demonstrated CD74 inhibition reversed radiation-induced AKT phosphorylation in microglia and promoted the M1 polarization in combination of radiation. Additionally, blocking the MIF-CD74 interaction between NSCLC and microglia promoted microglia M1 polarization. Furthermore, radiation improved tumor hypoxia to decrease HIF-1α dependent MIF secretion by NSCLC. MIF inhibition enhanced radiosensitivity for brain metastasis via synergistically promoting microglia M1 polarization in vivo.

CONCLUSIONS

Our study revealed that targeting the MIF-CD74 axis promoted microglia M1 polarization and synergized with radiotherapy for brain metastasis in NSCLC.

Ionizing radiation induces vascular smooth muscle cell senescence through activating NF-κB/CTCF/p16 pathway

Radiation injury of blood vessels (RIBV) is a serious long-term complication of radiotherapy, characterized by the development of atherosclerosis. The involvement of vascular smooth muscle cells (VSMCs) senescence in the pathogenesis of radiation-induced atherosclerosis has been implicated, yet the precise mechanisms governing VSMCs senescence remain inadequately comprehended. In this study, the senescence of VSMCs was examined by employing SA-β-gal staining and assessing the expression of p16 and p21, both in vivo and in vitro. Our findings revealed that ionizing radiation (IR) has the potential to augment cellular senescence. In addition, IR significantly activated the NF-κB pathway, as evidenced by increased p65 nuclear translocation, phospho-p65 expression, and enhanced binding ability of p65 (EMSA). Furthermore, a decrease in HMGB2 expression following exposure to IR was observed via Western blot analysis, while CTCF expression remained unchanged. Interestingly, the formation of CTCF spatial clustering was detected under super-resolution fluorescence microscopy. Concurrently, the ChIP technique identified the facilitation of the interaction between CTCF and p16 gene through IR. The inhibition of CTCF or the overexpression of HMGB2 through lentiviruses effectively eliminates the formation of CTCF clusters and the upregulation of p16 and p21 after IR. Inhibition of NF-κB activation induced by IR by PDTC (100 μM) led to a decrease in the staining of SA-β-gal, a reduction in p16 expression, an increase in HMGB2 protein expression and a decrease in CTCF clusters formation. This study provided significant insights into the role and mechanism of IR in VSMCs senescence by regulating NF-κB/CTCF/p16 pathway.

Genomic alterations associated with pseudoprogression and hyperprogressive disease during anti-PD1 treatment for advanced non-small-cell lung cancer

Introduction

This study aimed to elucidate the relationship between dynamic genomic mutation alteration and pseudoprogression (PsPD)/hyperprogressive disease (HPD) in immunotherapy-treated advanced non-small-cell lung cancer (NSCLC), to provide clinical evidence for identifying and distinguishing between PsPD and HPD.

Method

Patients with advanced NSCLC who were treated with anti-PD1 were enrolled. Whole blood was collected at baseline and post image progression. Serum was separated and sequenced using 425-panel next-generation sequencing analysis (NGS).

Results

NGS revealed that not only single gene mutations were associated with PsPD/HPD before treatment, dynamic monitoring of the whole-blood genome mutation spectrum also varied greatly. Mutational burden, allele frequency%, and relative circulating tumor DNA abundance indicated that the fold change after image progression was much higher in the HPD group.

Discussion

The gene mutation profiles of PsPD and HPD not only differed before treatment, but higher genome mutation spectrum post image progression indicated true disease progression in patients with HPD. This suggests that dynamic whole-genome mutation profile monitoring as NGS can distinguish PsPD from HPD more effectively than single gene detection, providing a novel method for guiding clinical immune treatment.

Classification of the immune microenvironment associated with 12 cell death modes and construction of a prognostic model for squamous cell lung cancer

PURPOSE

An increasing number of patients with lung squamous cell carcinoma (LUSC) are benefiting from immunotherapy. However, the individual immune profile of patients who respond to treatment is unclear. Multiple programmed cell death (PCD) patterns play an important role in the proliferation and differentiation of tumor cells, predicting the efficacy of immunotherapy using a risk model for programmed cell death gene combinations LUSC risk model.

METHODS

Genes associated with 12 types of PCD were analyzed to establish a prognostic model. Risk scores were calculated using PCDG-based expression profiles, and LUSC patients were classified into two groups. Tumor immune microenvironment (TIME) characteristics and immunotherapy responses were compared between the two groups. Finally, staging was predicted using the extreme gradient boosting tree algorithm (eXtreme Gradient Boosting, XGBoost), and an algorithmic model was constructed to predict the prognosis of LUSC patients based on the PCDG risk score.

RESULTS

A stepwise downscaling of 1256 PCDGs was performed to screen out 16 genes associated with LUSC prognosis to construct a risk model. Immune cell infiltration levels, the immunotherapy response, and prognostic differences were different between these two groups of patients. The classification prediction model based on the XGBoost algorithm and the prognostic model based on the risk score were able to distinguish the risk subtypes and individual prognosis of LUSC patients, respectively.

CONCLUSIONS

PCD patterns exert a crucial effect on the development of LUSC. An evaluation of different PCD patterns in LUSC improves the understanding of the characteristics of infiltrating immune cells and mutational features of the TIME, distinguishes LUSC patients who might benefit from immunotherapy, and predicts their future survival.

Maturation, Morphology, and Function: The Decisive Role of Intestinal Flora on Microglia: A Review

Recent studies have shown that the gut microbiota regulates intestinal function and maintains intestinal homeostasis, as well as interacting with the central nervous system to affect brain function and human behavior. Microglia are the most common immune cell type in the central nervous system during homeostasis. These cells play an important role in immune surveillance by responding to infections and other pathological conditions. Microglia also play a major role in maintaining brain homeostasis in both developing and adult mice by phagocytosing cell debris and regulating the formation of neural networks. The specific signaling pathways and cytokines that control the maturation and activation of microglia are currently not fully established. However, research on germ-free (GF) mice and specific pathogen-free (SPF) mice indicate that gut microbiota have important interactions with microglia. Here, we review the latest research findings on how gut microbiota can affect the morphology, maturation, phenotype and function of microglia. We also discuss recent advances in the gut microbiota-microglia-disease axis.

Targeting polymerase θ impairs tumorigenesis and enhances radiosensitivity in lung adenocarcinoma

Radioresistance remains a major obstacle to efficacious radiotherapy in non-small-cell lung cancer (NSCLC). DNA replication proteins are novel targets for radiosensitizers. POLQ is a DNA polymerase involved in DNA damage response and repair. We found that POLQ is overexpressed in NSCLC and is clinically correlated with high tumor stage, poor prognosis, increased tumor mutational burden, and ALK and TP5 mutation status; POLQ inhibition impaired lung tumorigenesis. Notably, POLQ expression was higher in radioresistant lung cancer cells than in wild-type cancer cells. Moreover, POLQ expression was further increased in radioresistant cells after radiation. Enhanced radioresistance is through a prolonged G2/M phase and faster repair of DNA damage, leading to reduced radiation-induced apoptosis. Novobiocin (NVB), a POLQ inhibitor, specifically targeted cancer cells. Genetic knockdown of POLQ or pharmacological inhibition by NVB decreased radioresistance in lung adenocarcinoma while causing little toxicity to normal pulmonary epithelial cells. In conclusion, POLQ is a promising and practical cancer-specific target to impair tumorigenesis and enhance radiosensitivity in NSCLC.

T Cell-Mediated Tumor Killing-Related Classification of the Immune Microenvironment and Prognosis Prediction of Lung Adenocarcinoma

BACKGROUND

Although immune checkpoint inhibitors (ICI) are a promising therapeutic strategy for lung adenocarcinoma (LUAD), individual subgroups that might benefit from them are yet to be identified. As T cell-mediated tumor killing (TTK) is an underlying mechanism of ICI, we identified subtypes based on genes associated with TTK sensitivity and assessed their predictive significance for LUAD immunotherapies.

METHODS

Using high-throughput screening techniques, genes regulating the sensitivity of T cell-mediated tumor killing (GSTTK) with differential expression and associations with prognosis were discovered in LUAD. Furthermore, patients with LUAD were divided into subgroups using unsupervised clustering based on GSTTK. Significant differences were observed in the tumor immune microenvironment (TIME), genetic mutation and immunotherapy response across subgroups. Finally, the prognostic significance of a scoring algorithm based on GSTTK was assessed.

RESULTS

A total of 6 out of 641 GSTTK exhibited differential expression in LUAD and were associated with prognosis. Patients were grouped into two categories based on the expression of the six GSTTK, which represented different TTK immune microenvironments in LUAD. Immune cell infiltration, survival difference, somatic mutation, functional enrichment and immunotherapy responses also varied between the two categories. Additionally, a scoring algorithm accurately distinguished overall survival rates across populations.

CONCLUSIONS

TTK had a crucial influence on the development of the varying TIME. Evaluation of the varied TTK modes of different tumors enhanced our understanding of TIME characteristics, wherein the changes in T cell activity in LUAD are reflected. Thus, this study guides the development of more effective therapeutic methods.

G-Quadruplex Linked DNA Guides Selective Transfection into Nucleolin-Overexpressing Cancer Cells

Gene therapy is a promising approach for treating tumors. Conventional approaches of DNA delivery depending on non-viral or viral vectors are unsatisfactory due to the concerns of biosafety and cell-targeting efficiency. The question how to deliver DNA into tumor cells efficiently and selectively is a major technological problem in tumor gene therapy. Here, we develop a vector-free gene transfer strategy to deliver genes effectively and selectively by taking advantage of targeting nucleolin. Nucleolin, a shuttle protein moving between cell membrane, cytoplasm and nuclei, is overexpressed in tumor cells. It has a natural ligand G-quadruplex (Gq). Gq-linked DNA (Gq-DNA) is likely to be internalized by ligand dependent uptake mechanisms independently of vectors after neutralizing negative charges of cell membrane by targeting nucleolin. This strategy is referred to as Gq-DNA transfection. Benefiting from its high affinity to nucleolin, Gq-DNA can be effectively delivered into nucleolin-positive tumor cells even nuclei. Gq-DNA transfection is characterized by low cytotoxicity, high efficiency, ease of synthesis, high stability in serum, direct access into nuclei, and specific nucleolin-positive tumor cell targeting.

The Predictive Value of PAK7 Mutation for Immune Checkpoint Inhibitors Therapy in Non-Small Cell Cancer

Background

To date, immunotherapy has improved the 5-year survival rate of patients with advanced non-small cell lung cancer (NSCLC) from 4% to 15%. However, only 30%-50% of the NSCLC patients respond to immune checkpoint inhibitors (ICIs) immunotherapy. Therefore, screening patients for potential benefit with precise biomarkers may be of great value.

Methods

First, an immunotherapy NSCLC cohort was analyzed to identify the gene mutations associated with the prognosis of ICI treatment. Further analyses were conducted using NSCLC cohort in The Cancer Genome Atlas (TCGA) project to validate the correlations between the specific gene mutations and tumor immunogenicity, antitumor immunity, and alterations in the tumor-related pathways using Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) and Gene set enrichment analysis (GSEA).

Results

In the immunotherapy NSCLC cohort (n = 266), significantly longer overall survival (OS) rates were observed in the PAK7-mutant type (PAK7-MT) group (n = 13) than the PAK7-wild type (PAK7-WT) group (n = 253) (P = 0.049, HR = 0.43, 95%CI = 0.23-0.79). In the TCGA cohort, PAK7 mutations were correlated with the higher tumor mutation burden (TMB) (14.18 vs. 7.13, P <0.001), increased neoantigen load (NAL) (7.52 vs. 4.30, P <0.001), lower copy number variation (CNV), and higher mutation rate in the DNA damage response (DDR)-related pathways. In addition, PAK7 mutations were also positively correlated with immune-related genes expressions and infiltrating CD8+ T cells (0.079 vs. 0.054, P = 0.005). GSEA results showed that several tumor-related pathways varied in the PAK7-MT group, suggesting the potential mechanisms that regulate the tumor immune-microenvironment.

Conclusions

This study suggested that the PAK7 mutations might be a potential biomarker to predict the efficacy of immunotherapy for NSCLC patients. Considering the heterogeneity among the patients and other confounding factors, a prospective clinical trial is proposed to further validate the impact of PAK7 mutation on the immunotherapy outcomes in NSCLC.

Crosstalk between macrophage-derived PGE2 and tumor UHRF1 drives hepatocellular carcinoma progression

Background: Tumor-associated macrophages (TAMs) and dysregulated tumor epigenetics contribute to hepatocellular carcinoma (HCC) progression. However, the mechanistic interactions between TAMs and tumor epigenetics remain poorly understood. Methods: Immunohistochemistry and multiplexed fluorescence staining were performed to evaluate the correlation between TAMs numbers and UHRF1 expression in human HCC tissues. PGE2 neutralizing antibody and COX-2 inhibitor were used to analyze the regulation of TAMs isolated from HCC tissues on UHRF1 expression. Multiple microRNA prediction programs were employed to identify microRNAs that target UHRF1 3'UTR. Luciferase reporter assay was applied to evaluate the regulation of miR-520d on UHRF1 expression. Chromatin immunoprecipitation (ChIP) assays were performed to assess the abundance of H3K9me2 in the KLF6 promoter and DNMT1 in the CSF1 promoter regulated by UHRF1. The functional roles of TAM-mediated oncogenic network in HCC progression were verified by in vitro colony formation assays, in vivo xenograft experiments and analysis of clinical samples. Results: Here, we find that TAMs induce and maintain high levels of HCC UHRF1, an oncogenic epigenetic regulator. Mechanistically, TAM-derived PGE2 stimulates UHRF1 expression by repressing miR-520d that targets the 3'-UTR of UHRF1 mRNA. In consequence, upregulated UHRF1 methylates H3K9 to diminish tumor KLF6 expression, a tumor inhibitory transcriptional factor that directly transcribes miR-520d. PGE2 reduces KLF6 occupancy in the promoter of miR-520d, dampens miR-520d expression, and sustains robust UHRF1 expression. Moreover, UHRF1 promotes CSF1 expression by inducing DNA hypomethylation of the CSF1 promoter and supports TAM accumulation. Conclusions: Capitalizing on studies on HCC cells and tissues, animal models, and clinical information, we reveal a previously unappreciated TAM-mediated oncogenic network via multiple reciprocal enforcing molecular nodes. Targeting this network may be an approach to treat HCC patients.

217 PROMOTER-SPECIFIC EXPRESSION OF THE IMPRINTED Igf2 GENE IN CATTLE

Insulin-like growth factor II (Igf2) is an imprinted gene crucial to fetal development and maternal/fetal nutrient transfer. Studies in the pig have demonstrated that this quantitative trait locus controls muscle growth, fat deposition, and heart size. Additionally, studies have shown that four splice variants transcribed from promoters (P1–P4) regulate the complex temporal and spatial expression of Igf2 in mice, humans, pigs, and horses. Cattle have a cotyledonary placenta and therefore a distinct type of maternal/fetal interaction. Here we have studied for the first time the promoter-specific expression of Igf2 in cattle, an economically valuable livestock species. Five naturally reproduced animals obtained from an abattoir were used in this study (2 mid-gestation fetuses, 1 calf, and 2 adults) of which all major internal organs were tested. Here we used RT-PCR to show that, like that of the pig and the human, the bovine Igf2 is expressed from four different promoters in a temporal and spatial manner. However, unlike for pigs and humans, we have found that transcripts from promoter P1 were present in several bovine fetal and adult tissues including the liver, heart, kidney, lung, placenta, and spleen. Promoter P2 was expressed only in mid-gestation fetal tissues including the liver, bladder, lung, and kidney. Promoter P2 was not detected in the brain. Promoter P3 was expressed ubiquitously throughout fetal and adult life; however, expression appears to be lower in the heart. Promoter P4 was expressed in all mid-gestation fetal tissues. Transcription from P4 decreased with age until transcripts were detected only in the kidney, lung, heart, and spleen. Using single-stranded conformational polymorphism polyacrylamide gel electrophoresis and a single nucleotide polymorphism in exon 10 of Igf2, we have confirmed that a loss of imprinting occurs with age from all transcripts (P1–P4) and biallelic expression is observed in most adult tissues studied. This work was funded by a grant from the USDA.

Spontaneous apoptosis in human colon tumor cell lines and the relation of wt p53 to apoptosis

OBJECTIVE

To examine spontaneous apoptosis of cultured human colon tumor cell lines in vitro and to investigate the role of wild type (wt) p53 in regulation of apoptosis induced by DNA-damaging treatment.

METHODS

A model system of human tumor progression involving three cell lines was used in this study for examination of apoptosis. They were originally established from human colon villous adenoma, including an early passage of non-tumorigenic cell line, V235E; a late passage of weakly tumorigenic cell line, V235L; and a spontaneous progressing highly tumorigenic cell line. V411. All of them maintain wt p53 expression. For identification of apoptosis, two tests were performed: 1. morphology study using acridine orange (AO)/ethidium bromide (EB) stainning by fluorescence microscopy; 2. DNA electrophoresis on agarose gel. P53 and WAF-1 (a downstream gene of p53) expressions were analysed at mRNA level using Northern blot technique. Apoptotic index of cell lines examined was measured by DNA fluorescence assay.

RESULTS

Spontaneous apoptosis was demonstrated in cell lines of all stages of progression by both morphology and DNA agarose gel electrophoresis. Apoptosis was further induced in V411 after treatment of cells with 137Cs gamma-irradiation and accompanied by increases in p53 and WAF-1 expression. In contrast, a mutant p53 bearing human colon cancer cell line, sw480, lacked spontaneous apoptosis, and upon irradiation neither induction of apoptosis nor increase expression of p53 and WAF-1 were seen.

CONCLUSIONS

Apoptosis can be maintained in some human tumor cell lines despite transformation and carcinogenesis. Wt p53 and WAF-1 products are two of the potential mediators which effect apoptosis. Additionally, since apoptosis was enhanced by irradiation in V411, but not in sw480, it suggests that wt p53 cancer cells are more sensitive to DNA-damaging treatment than mutant p53 cancer cells. These finding may have implications for cancer therapy.

Comparison of 5-mm and 6-mm Ablation Zones in Photorefractive Keratectomy for Myopia

BACKGROUND

Variation in ablation zone diameter may alter visual acuity and/or refractive effect in photorefractive keratectomy. Despite theoretical benefits of using a smaller diameter ablation zone, clinical studies suggest that a larger ablation zone may decrease problems associated with photorefractive keratectomy.

METHODS

The results of our initial 34 consecutive eyes treated with a 5-mm diameter ablation zone using a Summit Technology ExciMed UV200LA excimer laser were compared retrospectively to our initial 34 consecutive eyes treated with a 6-mm diameter ablation zone using a Summit OmniMed excimer laser. Eyes had a spherical equivalent refraction between -1.00 and -6.00 diopters (D) and astigmatism less than 1.00 D. Patients were followed for a minimum of 6 months.

RESULTS

Eyes treated with a 6-mm ablation zone had less hyperopia and a spherical equivalent refraction closer to emmetropia at 1, 2, and 3 months (P = 0.001). Eyes treated with a 6-mm ablation zone had better uncorrected visual acuity at 1 and 2 months (P = 0.001). Less subepithelial haze was noted at 2 months (P = 0.01) and 3 months (P = 0.002) in the 6-mm group. At 6 months postoperatively, 30 of 32 eyes (94%) treated with a 6-mm ablation zone had a spherical equivalent refraction within 0.50 D of emmetropia, and all 32 eyes (100%) were within 1.00 D of emmetropia; in the 5-mm ablation zone group, 28 of 34 eyes (80%) were within 0.50 D and 29 (85%) were within 1.00 D of emmetropia. Patients treated with a 6-mm ablation zone complained less of night halos and had fewer differences between night and day vision.

CONCLUSIONS

In this study of myopia of -1.00 D to -6.00 D, eyes treated with a 6-mm ablation zone achieve a more rapid visual recovery with less variation in refractive outcome and less adverse effects than those treated with a 5-mm ablation zone.