Elevation of H3K27me3 level contributes to the radioresistance of nasopharyngeal carcinoma by inhibiting OAS1 expression.

Radiotherapy has long been a main treatment option for nasopharyngeal carcinoma (NPC). However, during clinical treatment, NPC is prone to developing radioresistance, resulting in treatment failure. This study aims to examine the role of histone methylation in the induction of radioresistance. It was found that the radioresistance of NPC cells was related to the increase of the level of histone H3 lysine 27 trimethylation (H3K27me3). Treatment of cells with histone methyltransferase inhibitor GSK126 increased the radiosensitivity of NPC cells by triggering Bcl2 apoptosis regulator/BCL2-associated X, apoptosis regulator (Bcl2/BAX) signaling pathway. Bioinformatics analysis indicated that the expression of 2'-5'-oligoadenylate synthetase 1 (OAS1) was reduced in the radioresistant cells but increased in the GSK126-treated cells. Chromatin immunoprecipitation assay confirmed that the decrease of OAS1 expression in radioresistant cells was mainly due to the enrichment of H3K27me3 in its promoter region. Furthermore, downregulation of OAS1 reduced apoptosis due to the inhibition of Bcl2/BAX pathway after irradiation, while OAS1 overexpression increased radiosensitivity. Our findings revealed for the first time that the increase of H3K27me3 level was associated with the decrease of OAS1 expression, leading to the inhibition of apoptosis and ultimately contributing to the radioresistance of NPC cells. Moreover, the histone methyltransferase inhibitor GSK126 could overcome the radioresistance and thus might be a potential therapeutic strategy for NPC.NEW & NOTEWORTHY Our findings revealed for the first time that the increase of H3K27me3 level was associated with the decrease of OAS1 expression, leading to the inhibition of apoptosis and ultimately contributing to the radioresistance of NPC cells. Moreover, we demonstrated that the histone methyltransferase inhibitor GSK126 could be a promising therapeutic strategy for NPC by overcoming radioresistance, providing valuable insights into the clinical treatment of NPC.

Major changes in prevalence and genotypes of rotavirus diarrhea in Beijing, China after RV5 rotavirus vaccine introduction.

To analyze the epidemiological characteristics of group A rotavirus (RVA) diarrhea in Beijing between 2019 and 2022 and evaluate the effectiveness of the RV5 vaccine. Stool specimens were collected from patients with acute diarrhea, and RVA was detected and genotyped. The whole genome of RVA was sequenced by fragment amplification and Sanger sequencing. Phylogenetic trees were constructed using Bayesian and maximum likelihood methods. Descriptive epidemiological methods were used to analyze the characteristics of RVA diarrhea. Test-negative design was used to evaluate the vaccine effectiveness (VE) of the RV5. Compared with 2011-2018, RVA-positive rates in patients with acute diarrhea under 5 years of age and adults decreased significantly between 2019 and 2022, to 9.45% (249/634) and 3.66% (220/6016), respectively. The predominant genotype of RVA had changed from G9-VIP[8]-III between 2019 and 2021 to G8-VP[8]-III in 2022, and P[8] sequences from G8-VP[8]-III strains formed a new branch called P[8]-IIIb. The complete genotype of G8-VP[8]-III was G8-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. The VE of 3 doses of RV5 was 90.4% (95% CI: 28.8%-98.7%) against RVA diarrhea. The prevalence of RVA decreased in Beijing between 2019 and 2022, and the predominant genotype changed to G8P[8], which may be related to RV5 vaccination. Continuous surveillance is necessary to evaluate vaccine effectiveness and improve vaccine design.

Association between Cardiometabolic Index and Cognitive Function: A Cross-Sectional Study in a Diabetic-Based Population.

INTRODUCTION: Diabetes is a significant risk factor for cognitive impairment. Therefore, early identification of cognitive impairment in diabetic patients is particularly important. The aim of this study was to assess the relationship between Cardiometabolic index (CMI) and cognitive function in a diabetic population. METHODS: A cross-sectional study was conducted by collecting information from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Multiple linear regression models were used to investigate the correlation between CMI and low cognitive function in a diabetic population. Threshold effects analysis and fitted smoothing curves were used to describe the nonlinear links. Interaction tests and subgroup analyses were also performed. RESULTS: A total of 1,050 people participated in this study, including 561 men and 489 women. In the fully corrected model, CMI was positively associated with low cognitive performance as assessed by CERAD Word List Learning Test (CERAD W-L), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST) (OR = 1.37 [1.14, 1.72], p = 7.4 × 10-3), (OR = 1.21 [1.04, 1.51], p = 1.26 × 10-2), and (OR = 1.27 [1.08, 1.63], p = 2.53 × 10-2). Our study found that diabetic patients with higher CMI were at greater risk of developing low cognitive function. The effect of the subgroups on the positive association of CMI with cognitive impairment was not significant. A non-linear association between low cognitive performance and CMI was determined by CERAD W-L, AFT, and DSST (log-likelihood ratio <5 × 10-2). In addition, our also study found that CMI was a better predictor of cognitive impairment in diabetes than weight-adjusted waist index (WWI). CONCLUSION: Increased CMI is associated with an increased risk of cognitive impairment in people with diabetes. CMI can be used as a new anthropometric measure for predicting cognitive impairment in diabetes, with stronger predictive power than WWI.

P21 facilitates macrophage chemotaxis by promoting CCL7 in the lung epithelial cell lines treated with radiation and bleomycin.

BACKGROUND: Interstitial lung diseases (ILDs) can be induced and even exacerbated by radiotherapy in thoracic cancer patients. The roles of immune responses underlying the development of these severe lung injuries are still obscure and need to be investigated. METHODS: A severe lung damage murine model was established by delivering 16 Gy X-rays to the chest of mice that had been pre-treated with bleomycin (BLM) and thus hold ILDs. Bioinformatic analyses were performed on the GEO datasets of radiation-induced lung injury (RILI) and BLM-induced pulmonary fibrosis (BIPF), and RNA-sequencing data of the severely damaged lung tissues. The screened differentially expressed genes (DEGs) were verified in lung epithelial cell lines by qRT-PCR assay. The injured lung tissue pathology was analyzed with H&E and Masson's staining, and immunohistochemistry staining. The macrophage chemotaxis and activity promoted by the stressed epithelial cells were determined by using a cell co-culture system. The expressions of p21 in MLE-12 and Beas-2B cells were detected by qRT-PCR, western blot, and immunofluorescence. The concentration of CCL7 in cell supernatant was measured by ELISA assay. In some experiments, Beas-2B cells were transfected with p21-siRNA or CCL7-siRNA before irradiation and/or BLM treatment. RESULTS: After the treatment of irradiation and/or BLM, the inflammatory and immune responses, chemokine-mediated signaling pathways were steadily activated in the severely injured lung, and p21 was screened out by the bioinformatic analysis and further verified to be upregulated in both mouse and human lung epithelial cell lines. The expression of P21 was positively correlated with macrophage infiltration in the injured lung tissues. Co-culturing with stressed Beas-2B cells or its conditioned medium containing CCL7 protein, U937 macrophages were actively polarized to M1-phase and their migration ability was obviously increased along with the damage degree of Beas-2B cells. Furthermore, knockdown p21 reduced CCL7 expression in Beas-2B cells and then decreased the chemotaxis of co-cultured macrophages. CONCLUSIONS: P21 promoted CCL7 release from the severely injured lung epithelial cell lines and contributed to the macrophage chemotaxis in vitro, which provides new insights for better understanding the inflammatory responses in lung injury.

Hypomethylation of GDNF family receptor alpha 1 promotes epithelial-mesenchymal transition and predicts metastasis of colorectal cancer.

Tumor metastasis is the major cause of poor prognosis and mortality in colorectal cancer (CRC). However, early diagnosis of highly metastatic CRC is currently difficult. In the present study, we screened for a novel biomarker, GDNF family receptor alpha 1 (GFRA1) based on the expression and methylation data in CRC patients from The Cancer Genome Altlas (TCGA), followed by further analysis of the correlation between the GFRA1 expression, methylation, and prognosis of patients. Our results show DNA hypomethylation-mediated upregulation of GFRA1 in invasive CRC, and it was found to be correlated with poor prognosis of CRC patients. Furthermore, GFRA1 methylation-modified sequences were found to have potential as methylation diagnostic markers of highly metastatic CRC. The targeted demethylation of GFRA1 by dCas9-TET1CD and gRNA promoted CRC metastasis in vivo and in vitro. Mechanistically, demethylation of GFRA1 induces epithelial-mesenchymal transition (EMT) by promoting AKT phosphorylation and increasing c-Jun expression in CRC cells. Collectively, our findings indicate that GFRA1 hypomethylation can promote CRC invasion via inducing EMT, and thus, GFRA1 methylation can be used as a biomarker for the early diagnosis of highly metastasis CRC.

Temporal DNA methylation pattern and targeted therapy in colitis-associated cancer.

DNA methylation plays a crucial role in the pathogenesis of various diseases, including colorectal cancer (CRC). However, the global and temporal DNA methylation pattern during initiation and progression of colitis-associated cancer (CAC) are still unknown, including the potential therapeutic strategy of targeting methylation for CAC. In the present study, the global DNA methylation pattern was determined at different time points during CAC using DNA methylation sequencing, followed by the Starburst plot integrating alterations and potential functional prediction analysis. After demonstrating the regulatory role of DNA methyltransferases (DNMTs) on the expression of hub-genes in CRC cells, DNMT inhibitors were administered to treat CAC mice. Our results indicated that 811 genes were hypermethylated at different time points during initiation and progression of CAC. Genes that were downregulated and hypermethylated during CAC, including hub-genes BAD and inositol polyphosphate phosphatase-like 1 (INPPL1), were involved in MAPK signaling pathways, kit receptor signaling pathways, apoptosis and EGF/EGFR signaling pathways. Upregulated DNMTs (DNMT1, DNMT3A and DNMT3B) mediated downregulation and hypermethylation of BAD and INPPL1 in CAC and CRC cells. Low doses of DNMT inhibitors (decitabine (DAC) and azacitidine (AZA)) exerted efficient antitumor effects in CAC, accompanied with upregulation of BAD and INPPL1 expression, and apoptosis induction. In summary, the present study demonstrates the temporal DNA methylation pattern during CAC and provides a novel therapeutic strategy for treating this disease.

MiR-200a promotes epithelial-mesenchymal transition of endometrial cancer cells by negatively regulating FOXA2 expression.

Endometrial cancer is the most common gynecological cancer. Epithelial-mesenchymal transition (EMT) plays a critical role in tumor invasion and metastasis, which limits the success of treatment. Here, we investigated the roles of forkhead box A2 (FOXA2) and microRNA-200a (miR-200a) in regulating the EMT of endometrial cancer cells RL95-2. Empty vector or FOXA2 was stably transfected into RL95-2 cells. MTT assay measured cell proliferation, apoptosis assay measured apoptosis, Transwell invasion assay measured cell invasion, and Western blot measured the protein expression of FOXA2, E-cadherin, and vimentin. ChIP assay determined the binding of FOXA2 to E-cadherin promoter. For miR-200a analysis, the cells with stable FOXA2 expression were transfected with miR-negative control or miR-200a. Forced expression of FOXA2 decreased the proliferation and invasion, and increased the apoptosis of RL95-2 cells. FOXA2 also affected the EMT-associated proteins: FOXA2 increased the protein expression of E-cadherin and decreased the expression of vimentin. Moreover, FOXA2 positively regulated the promoter of E-cadherin in RL95-2 cells. Luciferase reporter assay identified FOXA2 as a target of miR-200a, which negatively regulated FOXA2. Western blot results showed that overexpression of miR-200a decreased the expression of E-cadherin but increased the expression of vimentin in the endometrial cancer cells by downregulating FOXA2 expression. FOXA2 may act as a tumor suppressor and inhibit EMT of endometrial cancer cells. FOXA2 expression is controlled by miR-200a, which promotes EMT of the endometrial cancer cells.

Long-term low-dose α-particle enhanced the potential of malignant transformation in human bronchial epithelial cells through MAPK/Akt pathway.

Since the wide usage of ionizing radiation, the cancer risk of low dose radiation (LDR) (<0.1 Gy) has become attractive for a long time. However, most results are derived from epidemiologic studies on atomic-bomb survivors and nuclear accidents surrounding population, and the molecular mechanism of this risk is elusive. To explore the potential of a long-term LDR-induced malignant transformation, human bronchial epithelial cells Beas-2B were fractionally irradiated with 0.025 Gy α-particles for 8 times in total and then further cultured for 1-2 months. It was found that the cell proliferation, the abilities of adhesion and invasion, and the protein expressions of p-ERK, p-Akt, especially p-P38 were not only increased in the multiply-irradiated cells but also in their offspring 1-2 months after the final exposure, indicating high potentiality of cell malignant transformation. On opposite, the expressions of p-JNK and p-P66 were diminished in the subcultures of irradiated cells and thus may play a role of negative regulation in canceration. When the cells were transferred with p38 siRNA, the LDR-induced enhancements of cell adhesion and invasion were significantly reduced. These findings suggest that long-term LDR of α-particles could enhance the potential of malignant transformation incidence in human bronchial epithelial cells through MAPK/Akt pathway.

Genotypic diversity and recombination of norovirus GI.6[P11] associated acute gastroenteritis outbreaks in Beijing, China, from 2016 to 2019.

Norovirus (NoV) is the leading pathogen responsible for global acute gastroenteritis (AGE) outbreaks and sporadic cases. NoV evolves through gene mutation and recombination, leading to the emergence of new strains capable of causing global epidemics. This study aimed to learn the epidemiological characteristics of 39 GI.6[P11] NoV outbreaks in Beijing, China, from 2016 to 2019 and to analyze the genetic diversity and phylogenetic process of GI.6[P11] strains. The Bayesian phylogenetic analysis of partial VP1 and RNA-dependent RNA polymerase (RdRp) genes showed that GI.6[P11] strains were clustered into four subclades. Eleven whole genome sequences were obtained through the amplicon sequencing with 16 pairs of newly designed primers. The phylogenetic trees based on the whole genome and ORF1, 2, and 3 showed that the clustering of the 11 strains was consistent with that of partial VP1 and RdRp genes. The Bayesian inference revealed that the most recent ancestor (TMRCA) for the four subclades of the phylogenetic tree based on the whole genome sequences was 2012.42, 2014.81, 2011.74, and 2015.53, respectively. The recombination sites of GI.6[P11] strains in Beijing were located near the ORF1/2 junction. The histo-blood group antigens (HBGA) binding sites of GI.6[P11] strains in Beijing were conserved and there were some unique amino acid mutations in non-structural proteins in the ORF1 region.

Split AAV8 Mediated ABCA4 Expression for Gene Therapy of Mouse Stargardt Disease (STGD1).

Adeno-associated virus (AAV)-based gene therapy has been shown to be safe and effective in numerous animal models and clinical trials for various ophthalmic diseases. Stargardt disease (STGD1; MIM #248200) is the most common autosomal recessive macular dystrophy disease, and the most common form is caused by mutations in the ABCA4 gene, a gene with 6.8 kb coding sequence. Split intein approaches increase the capacity of dual AAV gene therapy, but at the cost of reduced protein expression, which may be insufficient to achieve a therapeutic effect. In this study, we designed various dual split intein ABCA4 vectors and showed that the efficiency of expression of full-length ABCA4 protein is dependent on combinations of types and split sites of the intein system. The most efficient vectors were identified through in vitro screening, and a novel dual AAV8-ABCA4 vector was constructed and subsequently proven to express full-length ABCA4 protein at a high level, reducing bisretinoid formation and correcting the visual function of ABCA4-knockout mice. Furthermore, we evaluated therapeutic effects of different dosages by subretinal injection in mice model. Both therapeutic effects and safety were guaranteed under the treatment of 1.00 × 109 GC/eye. These results support the optimized dual AAV8-ABCA4 approach in future clinical translation for treatment of Stargardt disease.

Exploration of radiation-induced lung injury, from mechanism to treatment: a narrative review.

Background and Objective: Radiation-induced lung injury (RILI) is often found in thoracic tumor patients after thoracic radiation therapy, and influences patient quality of life. However, systematic exploration of RILI, including its molecular biological mechanisms and standardized treatment, has not yet been fully elucidated. The main objective of the narrative review was to describe the available evidence concerning RILI, from the biological mechanism to the clinical management. The underlying causes of RILI are multifactorial, including gene-level changes, the influence of signaling pathways, the convergence of various cells, as well as the expression of cytokines and chemokines. Based on the various mechanisms of RILI, several novel treatment strategies have been proposed and gradually applied in clinical practice. Methods: PubMed was used to collect articles about RILI from 1995 to 2021. The papers included clinical trials, reviews, as well as systematic reviews and meta-analyses. Based on the mechanism, diagnosis, and treatment, we synthesized and analyzed these papers to form a clearly logical and normative suggestion to guide clinical application. Key Content and Findings: RILI is a constantly developing and changing process including radiation pneumonitis and radiation lung fibrosis. Different kinds of inflammatory and immune cells such as macrophages, fibroblasts, and T cells play key roles in the development of RILI, and transforming growth factor-ß (TGF-ß), interleukin-4 (IL-4), IL-13, and interferon-γ (IFN-γ) are also participants in this process. At present, glucocorticoids are mainly therapeutic drugs for the early stage of RILI, and drugs treatment should abide early period, sufficient doses, and the individual principles. Other novel drugs such as Azithromycin also have been tried in clinical application. radiation dose, combination therapy modality, the condition of the tumor, and the age and underlying conditions of patients all effect the occurrence of RILI. Importantly, RILI has a relatively higher incidence in patients who received radiotherapy combined with other treatments, especially immunotherapy. Conclusions: The occurrence of RILI after radiotherapy will greatly affect the prognosis and quality of life of patients. In clinical practice, early intervention, active treatment, and more effective therapeutic drugs should be found.

Choline-induced SLC5A7 impairs colorectal cancer growth by stabilizing p53 protein.

The members of the solute carrier (SLC) superfamily are vital membrane transporters in human cells. In the present study, we determine the expression and function of SLC5 family members in colorectal cancer (CRC). Expression analysis based on The Cancer Genome Atlas database and potential clinical relation analysis based on the Oncomine database indicate that SLC5A7 is downregulated and is predicted to correlate with the staging, and prognosis response of CRC. Additional results demonstrate that SLC5A7 is downregulated and correlates with good prognosis in patients with CRC. Ectopic expression of SLC5A7 either by overexpression, or uptake of choline efficiently inhibits CRC growth. Examination of the molecular mechanism reveals that SLC5A7 promotes p53 protein expression by directly interacting with and modifying p53 and disrupting the interaction between p53 and MDM2 in wild type p53 CRC cells. Our findings establish the clear correlation between SLC5A7 and tumour growth, providing a novel potential therapeutic target for CRC.

The efficacy and safety of Zengxiao Jiandu decoction combined with definitive concurrent chemoradiotherapy for unresectable locally advanced non-small cell lung cancer: a randomized, double-blind, placebo-controlled clinical trial.

Background: Traditional Chinese medicine (TCM) makes a synergistic and attenuative effect when combined with chemoradiotherapy. However, strong evidence-based studies are lacking. The study sought to investigate whether Zengxiao Jiandu decoction as an adjunctive therapy is superior to definitive concurrent chemoradiotherapy (DCCRT) alone in unresectable, locally advanced (LA), stage III non-small cell lung cancer (NSCLC). Methods: Patients with unresectable LA-NSCLC were randomly assigned to receive DCCRT either combined with Zengxiao Jiandu decoction (TCM arm) or placebo therapy (Control arm), by computer-generated random assignment lists using a central randomization system. The patients were routinely followed-up every 3 months for the first 2 years after the therapy, and every 6 months for the subsequent 3 years, or earlier if clinically indicated. The primary endpoint was grade ≥3 chemoradiotherapy-related toxicities, while secondary endpoints included the completion rate of chemoradiotherapy, the clinical objective response rate (ORR), and survival. The placebo achieved full consistency in color, aroma, taste and appearance with the Zengxiao Jiandu decoction. Results: From February 2019 to December 2020, 163 patients were randomly allocated to TCM arm (n=82) or Control arm (n=81). Fifty-nine (72.0%) patients in TCM arm finished chemoradiotherapy per protocol and 79 (96.3%) received protocol-specified Zengxiao Jiandu decoction. Forty-two patients in Control arm finished chemoradiotherapy per protocol. The incidence of grade ≥3 chemoradiotherapy-related toxicities was higher in Control arm than TCM arm (44.4% vs. 31.7%, P=0.094). Grade ≥3 radiation pneumonitis occurred more frequently in Control arm than TCM arm (13.6% vs. 3.7%, P=0.024). The completion rate of the protocol-specified chemotherapy was significantly higher in TCM arm than Control arm (79.3% vs. 64.2%, P=0.033), but the completion rates of the definitive-dose radiotherapy were similar. There were no significant differences in ORR between the 2 arms. The progression-free survival (PFS) of TCM arm was significantly better than Control arm (median PFS, 12.0 vs. 9.0 months, P=0.035). However, Zengxiao Jiandu decoction was not found to produce any significant benefit in overall survival. Conclusions: The Zengxiao Jiandu decoction adjunctive therapy, as compared to DCCRT alone, reduced grade ≥3 radiation pneumonitis, improved the completion rate of DCCRT, and prolonged PFS for unresectable LA-NSCLC. Trial Registration: Chinese Clinical Trial Registry ChiCTR2000031667.

A specific upregulated long noncoding RNA in colorectal cancer promotes cancer progression.

Long noncoding RNA (lncRNA) plays a crucial role in the pathogenesis of various diseases, including colorectal cancer (CRC). The gene mutations of adenomatous polyposis coli (APC) were found in most patients with CRC. They function as important inducers of tumorigenesis. Based on our microarray results, we identified a specific upregulated lncRNA in CRC (SURC). Further analysis showed that high SURC expression correlated with poorer disease-free survival and overall survival in patients with CRC. Furthermore, we found that mutated APC genes can promote the transcription of SURC by reducing the degradation of ß-catenin protein in CRC. Functional assays revealed that knockdown of SURC impaired CRC cell proliferation, colony formation, cell cycle, and tumor growth. Additionally, SURC promotes CCND2 expression by inhibiting the expression of miR-185-5p in CRC cells. In conclusion, we demonstrate that SURC is a specific upregulated lncRNA in CRC and the SURC/miR-185-5p/CCND2 axis may be targetable for CRC diagnosis and therapy.

Promising Biomarkers of Radiation-Induced Lung Injury: A Review.

Radiation-induced lung injury (RILI) is one of the main dose-limiting side effects in patients with thoracic cancer during radiotherapy. No reliable predictors or accurate risk models are currently available in clinical practice. Severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) will reduce the quality of life, even when the anti-tumor treatment is effective for patients. Thus, precise prediction and early diagnosis of lung toxicity are critical to overcome this longstanding problem. This review summarizes the primary mechanisms and preclinical animal models of RILI reported in recent decades, and analyzes the most promising biomarkers for the early detection of lung complications. In general, ideal integrated models considering individual genetic susceptibility, clinical background parameters, and biological variations are encouraged to be built up, and more prospective investigations are still required to disclose the molecular mechanisms of RILI as well as to discover valuable intervention strategies.

Macrophage contributes to radiation-induced anti-tumor abscopal effect on transplanted breast cancer by HMGB1/TNF-α signaling factors.

Objectives: The roles of innate immunity including macrophages in radiation-induced abscopal effect (RIAE) are ambiguous. In this study, we evaluated the role of macrophage in RIAE and the interaction of cytokines in tumor microenvironment after irradiation. Materials and Methods: Transplanted tumor of breast cancer cells in BalB/C mice, severe combined immunodeficiency (SCID) mice and non-obese diabetic (NOD)-SCID mice were irradiated with fractionation doses to observe anti-tumor abscopal effect. The underlying mechanism of RIAE was investigated by treating the mice with TNF-α inhibitor or macrophage depletion drug and analyzing the alteration of macrophage distribution in tumors. A co-culture system of breast cancer cells and macrophages was applied to disclose the signaling factors and related pathways involved in the RIAE. Results: The growth of nonirradiated tumor was effectively suppressed in mice with normal or infused macrophages but not in mice with insufficiency/depletion of macrophage or TNF-α inhibition, where M1-macrophage was mainly involved. Investigation of the bystander signaling factors in vitro demonstrated that HMGB1 released from irradiated breast cancer cells promoted bystander macrophages to secret TNF-α through TLR-4 pathway and further inhibited the proliferation and migration of non-irradiated cancer cells by PI3K-p110γ suppression. Conclusions: HMGB1 and TNF-α contributes to M1-macrophages facilitated systemic anti-tumor abscopal response triggered by radiotherapy in breast cancer, indicating that the combination of immunotherapy and radiotherapy may has important implication in enhancing the efficiency of tumor treatment.

Dexamethasone enhances the lung metastasis of breast cancer via a PI3K-SGK1-CTGF pathway.

Dexamethasone (Dex), as a pretreatment agent, is widely used to attenuate the side effects of chemotherapy in breast cancer treatment. However, whether and how Dex affects breast cancer metastasis remain to be furtherly understood. In this study, we established several mouse breast cancer metastatic models to study the effect of Dex in vitro and in vivo. Transwell, Western Blot and RNA interference were applied to study the molecular mechanism of Dex in promoting breast cancer cell migration. Meanwhile, the effect of Dex on lung metastasis of breast cancer in Dex combined with PTX chemotherapy was discussed. Our results confirmed that Dex could promote breast cancer cell metastasis both in vitro and in vivo. Mechanistic studies revealed that this pro-metastatic effect of Dex was mediated by the GR-PI3K-SGK1-CTGF pathway in tumor cells. Ligation of Dex and glucocorticoid receptor (GR) on tumor cells activated the PI3K signaling pathway and upregulated serum glucocorticoid-inducible kinase 1 (SGK1) expression, and then increased the expression of connective tissue growth factor (CTGF) through Nedd4l-Smad2. Moreover, Dex was the leading factor for lung metastasis in a standard regimen for breast cancer treatment with paclitaxel and Dex. Importantly, targeting SGK1 with the inhibitor GSK650394 remarkably reduced lung metastasis in this regimen. Our present data provide new insights into Dex-induced breast cancer metastasis and indicate that SGK1 could be a candidate target for the treatment of breast cancer metastasis.

Role of Endoplasmic Reticulum and Mitochondrion in Proton Microbeam Radiation-Induced Bystander Effect.

It is well known that mitochondria and the endoplasmic reticulum (ER) play important roles in radiation response, but their functions in radiation-induced bystander effect (RIBE) are largely unclear. In this study, we found that when a small portion of cells in a population of human lung fibroblast MRC-5 cells were precisely irradiated through either the nuclei or cytoplasm with counted microbeam protons, the yield of micronuclei (MN) and the levels of intracellular reactive oxygen species (ROS) in nonirradiated cells neighboring irradiated cells were significantly increased. Mito/ER-tracker staining demonstrated that the mitochondria were clearly activated after nuclear irradiation and ER mass approached a higher level after cytoplasmic irradiation. Moreover, the radiation-induced ROS was diminished by rotenone, an inhibitor of mitochondria activation, but it was not influenced by siRNA interference of BiP, an ER regulation protein. While for nuclear irradiation, rotenone-enhanced radiation-induced ER expression, and BiP siRNA eliminated radiation-induced activation of mitochondria, these phenomena were not observed for cytoplasmic irradiation. Bystander MN was reduced by rotenone but enhanced by BiP siRNA. When the cells were treated with both rotenone and BiP siRNA, the MN yield was reduced for nuclear irradiation but was enhanced for cytoplasmic irradiation. Our results suggest that the organelles of mitochondria and ER have different roles in RIBE with respect to nuclear and cytoplasmic irradiation, and the function of ER is a prerequisite for mitochondrial activation.

Macrophage-Mediated Bystander Effects after Different Irradiations through a p53-dependent Pathway.

The goal of this work was to elucidate the mechanisms of bystander effects outside the localized irradiation field and their potential hematological toxicity. In this study, an in vitro multicellular co-culture system was used to investigate the intercellular commutation and related signaling pathways between either irradiated A549 cells or Beas-2B cells and bystander lymphoblast TK6 cells with or without macrophage U937 cells as an intermediator. Results showed that the proliferation ability of bystander TK6 cells was inhibited after co-culture with A549 cells irradiated with γ rays rather than carbon ions. When macrophages were contained in the co-culture system, the cell viability damage to the bystander TK6 cells were further enhanced. However, the proliferation inhibition of bystander TK6 cells after co-culture with irradiated Beas-2B cells was observed only when intermediator macrophages existed in the cell co-culture system. More serious cell injury was detected after carbon-ion irradiation compared with γ-ray irradiation. The p53-relevant apoptosis pathway was activated in both irradiated A549 and Beas-2B cells, each to a different extent. When the p53 pathway of irradiated cells was inhibited by PFT-α, PFTµ or p53 siRNA, the bystander damage to TK6 cells were clearly alleviated. In conclusion, the bystander lymphoblast damage was induced in different cells using different LET radiations. An amplified bystander response was modulated by the intermediator macrophage. The underlying molecular mechanisms of these bystander effects were dependent on the activation of p53 and its relevant apoptosis pathway in the irradiated cells. These results suggest that the bystander and macrophage-mediated bystander effects contribute to the common acute side effect of lymphocytopenia after local irradiation.