Circular RNA circFBXO7 attenuates non-small cell lung cancer tumorigenesis by sponging miR-296-3p to facilitate KLF15-mediated transcriptional activation of CDKN1A

BACKGROUND

Accumulating evidence indicates that circular RNAs (circRNAs) play important roles in various cancers. Hsa_circ_0008832 (circFBXO7) is a circRNA generated from the second exon of the human F-box only protein 7 (FBXO7). Mouse circFbxo7 is a circRNA generated from the second exon of mouse F-box only protein 7 (Fbxo7). The role of human circFBXO7 and mouse circFbxo7 in non-small cell lung cancer (NSCLC) has not been reported.

METHODS

The expression of circFBXO7 was measured by quantitative real-time PCR. Survival analysis was performed to explore the association between the expression of circFBXO7 and the prognosis of patients with NSCLC. Lung cancer cell lines were transfected with plasmids. Cell proliferation, cell cycle, and tumorigenesis were evaluated to assess the effects of circFBXO7. Fluorescence in situ hybridization assay was used to identify the location of circFBXO7 and circFbxo7 in human and mouse lung cancer cells. Luciferase reporter assay was conducted to confirm the relationship between circFBXO7 and microRNA.

RESULTS

In this study, we found that circFBXO7 was downregulated in NSCLC tissues and cell lines. NSCLC patients with high circFBXO7 expression had prolonged overall survival. Overexpression of circFBXO7 inhibited cell proliferation both in vitro and in vivo. Mechanistically, we demonstrated that circFBXO7 upregulated the expression of miR-296-3p target gene Krüppel-like factor 15 (KLF15) and KLF15 transactivated the expression of CDKN1A.

CONCLUSIONS

CircFBXO7 acts as a tumor suppressor by a novel circFBXO7/miR-296-3p/KLF15/CDKN1A axis, which may serve as a potential biomarker and therapeutic target for NSCLC.

Altered phenotypic and metabolic characteristics of FOXP3+CD3+CD56+ natural killer T (NKT)-like cells in human malignant pleural effusion

Malignant pleural effusion (MPE) is a functional 'cold' tumor microenvironment in which the antitumor activity of CD8⁺ T cells and natural killer T (NKT)-like cells is suppressed and the function of regulatory T (T_reg) cells is enhanced. Using flow cytometry and immunofluorescence staining, we detected a distinct subset of NKT-like cells expressing FOXP3 in MPE. Through single-cell RNA sequencing (scRNA-seq) analysis, we found that the glycolysis pathway and pyruvate metabolism were highly activated in FOXP3⁺ NKT-like cells. Similar to T_reg cells, FOXP3⁺ NKT-like cells highly expressed monocarboxylate transporter 1 (MCT1) and lactate dehydrogenase B to uptake and utilize lactate, thereby maintaining their immunosuppressive function and hyperlactylation in MPE. Furthermore, we found that MCT1 small molecule inhibitor 7ACC2 significantly reduced FOXP3 expression and histone lactylation levels in NKT-like cells in vitro. In conclusion, we reveal for the first time the altered phenotypic and metabolic features of FOXP3⁺ NKT-like cells in human MPE.

High-risk early-stage lung adenocarcinoma patients are identified by an immune-related circadian clock gene signature

Background

Twenty-four-hour oscillations of circadian rhythms control comprehensive biological processes in the human body. In lung adenocarcinoma (LUAD), chronic circadian rhythm disruption is positively associated with tumorigenesis. However, few studies focus on circadian clock gene signatures (CGSs) for prognosis evaluation of patients with early-stage LUAD.

Methods

In this study, we aimed to construct a robust prognostic circadian rhythm-related biomarker from multiple public databases, including the Gene Expression Omnibus database and The Cancer Genome Atlas database. The least absolute shrinkage and selection operator (LASSO)-penalized Cox regression model was performed to select optimal circadian clock gene pairs. Bioinformatic analyses were performed to estimate the abundance of different immune cells and immunohistochemical analyses were conducted to validate the differential proportion of tumor-infiltrating lymphocytes in different groups.

Results

Results demonstrated that the CGS could accurately identify patients with early-stage LUAD at a high risk in the training dataset [hazard ratio (HR) =3.06; 95% confidence interval (CI): 2.47–3.78; P<0.001], testing dataset (HR =2.44; 95% CI: 1.74–3.43; P<0.001), and validation dataset (HR =2.09, 95% CI: 1.09–4.00; P=0.023). Bioinformatic and immunohistochemical analyses demonstrated that the abundance of tumor-infiltrating CD4⁺ T cells was higher in the low-CGS groups. Integration of the CGS and clinical characteristics improved the accuracy of the CGS in predicting overall survival (OS) of patients with early-stage LUAD.

Conclusions

In conclusion, the CGS was an independent immune-related circadian biomarker that could identify early-stage LUAD patients with different OS.

Lactate in the tumour microenvironment: From immune modulation to therapy

Disordered metabolic states, which are characterised by hypoxia and elevated levels of metabolites, particularly lactate, contribute to the immunosuppression in the tumour microenvironment (TME). Excessive lactate secreted by metabolism-reprogrammed cancer cells regulates immune responses via causing extracellular acidification, acting as an energy source by shuttling between different cell populations, and inhibiting the mechanistic (previously ‘mammalian’) target of rapamycin (mTOR) pathway in immune cells. This review focuses on recent advances in the regulation of immune responses by lactate, as well as therapeutic strategies targeting lactate anabolism and transport in the TME, such as those involving glycolytic enzymes and monocarboxylate transporter inhibitors. Considering the multifaceted roles of lactate in cancer metabolism, a comprehensive understanding of how lactate and lactate-targeting therapies regulate immune responses in the TME will provide insights into the complex relationships between metabolism and antitumour immunity.

Development and Validation of a Prognostic Autophagy-Related Gene Pair Index Related to Tumor-Infiltrating Lymphocytes in Early-Stage Lung Adenocarcinoma

The role of autophagy in lung cancer is context-dependent and complex. Recent studies have reported the important role of autophagy in tumor immune escape. However, the association between autophagy and tumor-infiltrating lymphocytes (TILs) in early-stage lung adenocarcinoma (LUAD) remains unclear. In this study, we aimed to develop and validate the autophagy-related gene pair index (ATGPI) and autophagy clinical prognostic index (ACPI) in multiple LUAD cohorts, including The Cancer Genome Atlas (TCGA) cohort, Gene Expression Omnibus cohorts, and one cohort from Union Hospital, Wuhan (UH cohort), using a Cox proportional hazards regression model with the least absolute shrinkage and selection operator. Multivariate Cox regression analysis demonstrated that there was a significant difference in overall survival (OS) between patients with high and low ATGPI in the testing [hazard ratio (HR) = 1.97; P < 0.001] and TCGA validation (HR = 2.25; P < 0.001) cohorts. Time-dependent receiver operating characteristic curve analysis was also performed. We found that high ATGPI could accurately identify patients with early-stage LUAD with shorter OS, with the areas under the curve of 0.703 and 0.676 in the testing and TCGA validation cohorts, respectively. Concordance index (C-index) was used to evaluate the efficiency of ATGPI and ACPI. The C-index of ACPI was higher than that of ATGPI in the testing (0.71 vs. 0.66; P < 0.001), TCGA validation (0.69 vs. 0.65; P = 0.028), and UH (0.80 vs. 0.70; P = 0.015) cohorts. TIL analysis demonstrated that the proportions of tumor-infiltrating CD4⁺ T cells were lower in the high-ATGPI group than in the low-ATGPI group in both the TCGA validation and UH cohorts. These results indicate the potential clinical use of ATG signatures which are associated with TILs, in identifying patients with early-stage LUAD with different OS.

[Value of PET/MRI in the diagnosis of malignant pleural effusion in comparison with PET/CT]

Objective: To investigate the diagnostic value of PET/MRI for malignant pleural effusion (MPE), and compare its diagnostic difference with PET/CT. Methods: The data of 57 patients with suspected MPE admitted into Union Hospital of Tongji Medical College of Huazhong University of Science and Technology from October 2017 to January 2020 was analyzed. A total of 53 patients were included in the prospective study, and the whole body PET/CT and thoracic PET/MRI were performed on them respectively. Two physicians used a blind method to evaluate the morphological features of PET/CT and PET/MRI images, delineate the region of interest (ROI), obtain the maximum standard uptake value (SUVmax) of the ROI in the PET/CT and PET/MRI images. The target-to-background ratio (TBR) of the lesion was calculated. The diffusion-weighted imaging (DWI) characteristics of the pleura in PET/MRI images were analyzed. Taking pathological diagnosis as the gold standard, the diagnostic effect of PET/CT and PET/MRI on MPE were evaluated. Results: The 53 patients who were finally included were (62.8±1.7) years old, consisting of 31 males. Pathological results showed that 41 cases were MPE and 12 cases were benign pleural effusion (BPE). There were no statistical differences in age, gender and smoking history between the two groups (P>0.05). Bland-Altman analysis showed that the SUVmax of pleural lesions by PET/MRI was higher than that by PET/CT (6.4±0.6 vs 5.3±0.5, P<0.001). The TBR of PET/MRI was higher than that of PET/CT (2.2±0.2 vs 1.8±0.2, P<0.001). The sensitivity, specificity, and accuracy of PET/MRI in the diagnosis of MPE by combining imaging features such as SUVmax and DWI of pleural lesions were 75.6%, 100%, and 81.1%, respectively. The sensitivity, specificity, and accuracy of PET/CT combined with SUVmax and imaging features of pleural lesions in the diagnosis of MPE were 85.4%, 83.3%, and 77.4%, respectively. There was no statistically significant difference between PET/MRI and PET/CT in the area under the curve (AUC) for diagnosing MPE (0.934 vs 0.873, P>0.05). Conclusions: PET/MRI and PET/CT have the equivalent diagnostic efficiency for MPE. However, PET/MRI shows higher SUVmax and TBR for pleural lesions, and has specific pleural DWI imaging characteristics, which is worthy of further clinical research.

Accumulation of TNFR2-expressing regulatory T cells in malignant pleural effusion of lung cancer patients is associated with poor prognosis

Background

Regulatory T cells (Tregs) may represent a major cellular mechanism in immune suppression by dampening the anti-tumor response in malignant pleural effusion (MPE). Tumor necrosis factor receptor type II (TNFR2) has emerged as a novel identification for the maximally suppressive subset of Tregs in the tumor environment. At present, the significance of TNFR2 expression on Tregs in MPE remains unclear.

Methods

The distribution of TNFR2⁺cells in Tregs and effector T cells (Teffs) in MPE, peripheral blood (PB), and tuberculosis pleural effusion (TPE) were determined. The associations between TNFR2⁺Tregs frequencies present in MPE and the clinical and laboratorial characteristics of patients with lung cancer were investigated. The immunosuppressive phenotype of TNFR2⁺Tregs in MPE was analyzed. The effects of the TNF-TNFR2 interaction on the immunosuppressive function of Tregs was explored. The efficacy of targeting TNFR2 for MPE therapy was examined. The source of TNF in MPE was identified.

Results

We observed that markedly higher levels of TNFR2 were expressed in MPE Tregs compared with the levels expressed in MPE Teffs, PB Tregs, or in TPE Tregs. The frequencies of TNFR2⁺Tregs were positively correlated with the number of tumor cells in MPE, as well as the volume of MPE. High frequencies of TNFR2⁺Tregs in MPE indicated short survival time and poor performance status for MPE patients. Compared to TNFR2^-Tregs, TNFR2⁺Tregs expressed higher levels of immunosuppressive molecules cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death-ligand 1 (PD-L1), and replicating marker Ki-67. Consequently, the proportions of interferon gamma (IFN-γ)-producing cytotoxic T lymphocytes (CTLs) were significantly increased after TNFR2 blockade. Furthermore, tumor necrosis factor (TNF), through interaction with TNFR2, enhanced the suppressive capacity of Tregs by up-regulating CTLA-4 and PD-L1 expression. Interestingly, T helper 1 (Th1) and T helper 17 (Th17) cells are the major source of TNF in MPE, suggesting that MPE Teffs may paradoxically promote tumor growth by boosting MPE Treg activity via the TNF-TNFR2 pathway.

Conclusions

Our data expanded the immunosuppressive mechanism present in MPE induced by Tregs, and provides novel insight for the diagnosis, disease evaluation, and treatment of MPE patients.

Interleukin-26 upregulates interleukin-22 production by human CD4+ T cells in tuberculous pleurisy

IL-26 is a potentially important player in host defense and may be a pathogenic factor in the chronic inflammatory disorders of humans. However, the involvement of IL-26 in tuberculous pleural effusion (TPE) has not been investigated. The concentration of IL-26 was determined in pleural fluids and sera from patients with pleural effusions. Flow cytometry was performed to identify the cell origin of IL-26. The effects of tuberculosis-specific antigen (ESAT-6/CFP-10) on IL-26 expression of CD4+ T cell were explored. The impacts of IL-26 on modulating CD4+ T cell polarization were also investigated. The concentrations of IL-26 were much higher in tuberculous, malignant, and infectious PE than those in the corresponding serum. The expression of IL-26 on CD4+ T cells was much higher in tuberculous PE than those in the corresponding serum, and pleural Th1 and Th17 cells might be the major cell sources of IL-26. The addition of ESAT-6/CFP-10 to CD4+ T cells led to increasing the number of IL-26-producing CD4+ T cells and IL-26 expression on Th1 and Th17 cells. IL-26 could induce the differentiation and generation of IL-22 by memory and naive CD4+ T cells. IL-26 also upregulated the mRNA encoding CC-chemokine ligand 20 (CCL20) and CCL22 by mononuclear cells isolated from TPE. This study implies that pleural Th1 and Th17 cells are the major cell sources of IL-26, which could induce the differentiation and generation of Th22 cells by CD4+ T cells, suggesting the involvement of IL-26 in the pathogenesis of human TPE. KEY MESSAGES: IL-26 is overexpressed in TPE patients and presents a higher concentration in pleural effusion than the corresponding peripheral blood. Pleural Th1 and Th17 cells might be the major cell sources of IL-26 in TPE patients. IL-26 promotes IL-22 secretion and Th22 generation by CD4+ T cells isolated from TPE patients. IL-26 may play an active role in the pathogenesis of tuberculous pleurisy.

Hypertension: What are the self-care and health-care-seeking behaviours in women over time?

The aim of this study was to estimate the prevalence and incidence of hypertension in women, and describe their self-care and health-seeking behaviours. This research was conducted as part of the Australian Longitudinal Study on Women's Health, a study comprising a nationally representative sample of Australian women in three age groups. The focus of this research is 14 099 women born in 1946-1951, who have been surveyed six times (1996-2010). Student t-tests were used to compare women who did or did not have hypertension by their health-care utilization. Longitudinal analyses were conducted using a Poisson generalized estimating equation model. The incidence of hypertension among this cohort during 1996 to 2010 ranged from 400 to 597 participants per survey, resulting in an increase in prevalence of hypertension from 20.9% in 1996 to 41.3% in 2010. For all survey periods, women with hypertension had a significantly higher average number of visits to doctors and allied health practitioners compared with women without hypertension (P<0.005). The use of complementary medicine (practitioners and self-prescribed treatments) by women with hypertension was significantly lower compared to women without hypertension (P<0.005). Over time, conventional health-care utilization was higher for women with hypertension compared with women without hypertension (adjusted RR=1.18; 95% CI: 1.14, 1.22; P<0.0001). Our findings show that women with hypertension are using a range of conventional and complementary and alternative medicine: with hypertensive women using more conventional medicine and less complementary and alternative medicine than non-hypertensive women. As such, health-care providers should communicate with their patients regarding their use of complementary and alternative medicine in their efforts to provide safe, effective and coordinate care.