Regulation of gonadotropin-releasing hormone (GnRH) gene expression by insulin-like growth factor I in a cultured GnRH-expressing neuronal cell line

A GnRH-expressing neuronal cell line (NLT) was used to determine whether insulin-like growth factor I (IGF-I) regulates GnRH gene expression. A receptor-binding assay demonstrated the expression of IGF-I receptors on NLT cells. Activation of IGF-I receptors induced the Ras/Raf-1/mitogen-activated protein kinase pathway and increased c-fos expression. NLT cells treated with IGF-I underwent cell proliferation and exhibited a growth-independent increase in mouse GnRH mRNA expression. In cells transfected with DNA constructs containing the human GnRH promoter, which includes a consensus AP-1 binding site fused to the luciferase reporter gene, a significant increase in reporter activities was induced by IGF-I, whereas mutation of this AP-1 site significantly reduced IGF-I-induced promoter activation. These results demonstrate that IGF-I serves as an important signal in the regulation of both human and rodent GnRH gene expression.

An alternative gonadotropin-releasing hormone (GnRH) RNA splicing product found in cultured GnRH neurons and mouse hypothalamus

Gonadotropin-releasing hormone (GnRH) is encoded by the proGnRH gene which contains four exons and three introns. In this study, two immortalized GnRH-expressing cell lines (Gn11 and NLT) were characterized. The NLT and Gn11 cells, derived from a same brain tumor in a transgenic mouse, display neuronal morphology and neuron-specific markers. However, NLT cells secrete much higher levels of GnRH than Gn11 cells. To delineate the mechanism underlying this difference, reverse transcriptase-polymerase chain reaction and RNase protection assays were performed to examine proGnRH gene expression. While the mature proGnRH mRNA was predominately expressed in NLT cells, Gn11 cells express an abundant short transcript. Sequence analysis revealed that this short transcript contains exons 1, 3, and 4, but not exon 2, which encodes the GnRH decapeptide. RNase protection assays demonstrated that NLT cells express much higher levels of mature proGnRH mRNA than Gn11 cells. The lower level of GnRH secreting capacity in Gn11 cells is due, in part, to decreased expression of mature proGnRH mRNA. When proGnRH gene expression in the mouse brain was examined, the same short splicing variant was observed in the olfactory area and preoptic area-anterior hypothalamus. But the prevalent transcript in these regions was the mature proGnRH mRNA. In contrast, only the mature proGnRH mRNA was found in the caudal hypothalamus. These results suggest that alternative splicing may be one of the mechanisms regulating proGnRH gene expression in the animal brain.

Rapid arrest of seizures with an inhalation aerosol containing diazepam

Diazepam (DZP) and a mixture of Chinese herbs customarily used to treat epilepsy were prepared as an aerosol under the trade name Aerosolum Diaiepami Compositae or Flvalscop (FVS). FVS was studied in a single-blind trial in 101 patients with seizures preceded by an aura and in 19 without an aura to whom was administered by another person. FVS or a control preparation was administered. In 16-22 s, (average 18.5 s), the aura was interrupted and no seizure ensued in 90% of the cases treated with FVS and in 26% of cases treated with the control preparation. Of the 120 patients, 8 had elementary partial seizures with Jacksonian march, 18 had complex partial seizures (CPS), 7 had simple partial seizures with autonomic symptoms, and 87 had secondarily generalized tonic-clonic seizures. Eleven patients have now received FVS for 2 years (400 ml each). Forty patients for 1 year (150-200 ml each); none of these patients have shown any side effects or abnormal laboratory findings. An aerosol-administered drug may be a valuable adjunct to the antiepileptic drug (AED) arsenal and merits more extensive evaluation.

Tumor suppressor function of BCSC-1 in nasopharyngeal carcinoma

BCSC-1 is dramatically upregulated in CNE-2L2 human nasopharyngeal carcinoma cells with reduced malignancy (AS cells) and is proposed to be a candidate tumor suppressor gene. We therefore examined the effect of BCSC-1 expression on malignant behaviors of CNE-2L2 cells. Growth in vitro and tumorigenesis in nude mice of wild-type CNE-2L2 cells (W cells) were inhibited by ectopic BCSC-1, and those of AS cells were promoted by BCSC-1 suppression. The tumor suppressor function of BCSC-1 was further confirmed by a study showing that intratumor BCSC-1 injection caused growth suppression of the tumor from W cells inoculated in nude mice. Immunohistochemistry exhibited marked reduction of BCSC-1 expression in 11 of 39 human nasopharyngeal carcinoma specimens. Because BCSC-1 expression was as rich as that in normal cells in the rest of the carcinoma specimens and was poor in CNE-2L2 cells, HNE-1 human nasopharyngeal carcinoma cells with rich BCSC-1 expression were used as a control in the study. No effect of BCSC-1 transfection on growth of the cells was observed. The data suggest that BCSC-1 suppression might play roles in tumorigenesis of some nasopharyngeal carcinomas and that BCSC-1 might be a potential gene therapy target in nasopharyngeal carcinomas with poor BCSC-1 expression. Enhanced aggregation of cells together with increased E-cadherin and alpha-catenin expression and reduced Wnt signaling might be involved in the mechanisms of tumor suppressor function of BCSC-1.

The effect of blockade of kappa-opioid receptors in the medial basal hypothalamus and medial preoptic area on luteinizing hormone release during midpregnancy in the rat

The objective of this study was to determine if kappa-opioid receptors present in the medial preoptic area (MPOA) and medial basal hypothalamus (MBH) are involved in opioid peptide suppression of LH secretion during midpregnancy (day 13-16) in the rat. Nor-binaltorphimine (nor-BNI), a selective antagonist of brain kappa-opioid receptors, was applied directly to the MPOA or MBH for 3.5 h by means of push-pull perfusion. Nor-BNI perfusion in the MBH produced a dose-dependent increase in LH pulse frequency as well as increases in blood LH level. The effect on amplitude could not be determined, since too few pulses occurred in cerebrospinal fluid-treated control rats. Nor-BNI perfusion in the MPOA also increased LH pulse frequency. Moreover, in the majority (62%) of rats perfused with nor-BNI in the MPOA, the final 1.5 h of perfusion were unexpectedly characterized by an increase in LH that was of greater magnitude and more prolonged than an LH pulse and produced an elevation in blood LH levels. This delayed LH response did not occur in any rat perfused in the MBH. Perfusion with nor-BNI in the diagonal band of Broca had no significant effect on LH secretion. The LH responses observed during nor-BNI perfusion in the MPOA or MBH were not due to spread to the third ventricle and subsequent diffusion via the cerebrospinal fluid to another brain site, since perfusion with nor-BNI in an area of the ventral thalamus close to the third ventricle had no effect on LH release. These results provide support for the involvement of kappa-opioid receptor-mediated mechanisms in both the MPOA and MBH in the suppression of LH secretion during midgestation in the rat.

Fibroblast activation protein in the tumor microenvironment predicts outcomes of PD-1 blockade therapy in advanced non-small cell lung cancer

PURPOSE

The identification of robust predictive biomarkers of the response to programmed cell death-1 (PD-1) blockade remains a critical concern. Here, we investigated on fibroblast activation protein (FAP) as a microenvironment-derived biomarker of clinical outcomes of PD-1 blockade therapy, and the correlation between FAP expression and T cell infiltration in advanced non-small cell lung cancer (NSCLC).

METHODS

A total of 135 patients with advanced NSCLC who received PD-1 blockade therapy were retrospectively analyzed. The potential associations among FAP expression, CD3 + T cell and CD8 + T cell infiltration, and clinical outcomes of immunotherapy were validated by immunohistochemistry, bioinformatic analyses, and statistical measurements.

RESULTS

FAP was widely expressed in advanced NSCLC tissues. FAP was correlated with decreased density of CD8 + T cells (Spearman's rho  - 0.32, p < 0.001) and immunosuppressive tumor microenvironment (TME) status. No correlations were detected between FAP and PD-L1 expression or with the density of CD3 + T cells. The patients with higher expression of FAP showed worse response rate (16.4% vs. 38.7%, p < 0.001) and worse progression-free survival (HR = 2.56, 95% CI 1.69-3.87, p < 0.001). In addition, FAP contributed to shortened overall survival in subgroups of the patients with squamous cell lung cancer (p = 0.020), PD-1 blockade monotherapy (p = 0.017), and first-line therapy (p = 0.028).

CONCLUSION

FAP is a potential predictive biomarker of resistance to PD-1 blockade. Further investigation is warranted to identify a strategy for targeting FAP to alleviate the immunosuppressive TME and broaden the clinical effectiveness of PD-1 blockade therapy.

Assessment of topical therapy of the burn wound with silver sulphadiazine after its use for 15 years in a burn unit

A comparative study of patients receiving or not receiving topical applications of 1 per cent silver sulphadiazine cream as treatment for burn wounds has shown that the drug is still effective in significantly reducing the amount of bacterial contamination of burn wounds, even after 15 years of use in our Burn Unit. Consequently the overall mortality due to burn wound sepsis has been decreased in this Burn Unit.

Lack of catecholamine involvement in the increased luteinizing hormone release due to blockade of kappa-opioid receptors in the medial basal hypothalamus during midpregnancy in the rat

Blockade of kappa-opioid receptors in the medial basal hypothalamus (MBH) with nor-binaltorphimine (nor-BNI) stimulates luteinizing hormone (LH) release during midpregnancy in the rat [48]. The objective of this study was to determine whether norepinephrine (NE) or dopamine (DA) mediates the LH response to blockade of MBH kappa-opioid receptors on days 13-17 of pregnancy in the rat. Two experiments were conducted. In the first, push-pull perfusion in conjunction with HPLC was used to monitor in vivo NE release in the MBH occurring in response to (a) artificial CSF followed by CSF containing nor-BNI (40 micrograms/h), (b) desipramine (DMI, a NE reuptake blocker, 10 microM) in CSF followed by DMI, and (c) DMI followed by DMI+nor-BNI. Blood samples were taken at 12 min intervals concurrent with push-pull perfusate samples. Plasma LH levels were determined by RIA. Nor-BNI significantly increased LH release compared to CSF alone, but perfusate NE was undetectable in either perfusion period. However, perfusion with CSF containing 100 mM K+ in these rats markedly increased perfusate NE levels, indicating noradrenergic nerve terminals were present at the perfusion sites in the MBH. Addition of DMI to the CSF significantly increased perfusate NE levels, but produced no change in LH release. Nor-BNI+DMI perfusion increased LH secretion similar to nor-BNI alone, but produced no additional increase in MBH perfusate NE levels compared to perfusion with DMI alone.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of norepinephrine in mediating luteinizing hormone release in response to blockade of kappa-opioid receptors in the medial preoptic area

Our previous study [32] indicated that blockade of kappa-opioid receptors with nor-binaltorphimine (nor-BNI) in the medial preoptic area (MPOA) produced two different LH responses during midpregnancy in the rat: an increase in basal pulsatile LH secretion, followed in many cases by a larger and/or sustained increase in LH release. In the present study, two experiments were conducted to examine the role of norepinephrine (NE) in mediating these different LH responses. In experiment 1, the effects of NE synthesis inhibition with FLA-63 on nor-BNI induced LH secretion were examined. In 5 of 9 vehicle pretreated rats, nor-BNI perfusion in the MPOA produced only an increase in basal pulsatile LH secretion. In the remaining 4 animals blockade of MPOA kappa-receptors produced not only an increase in basal LH secretion, but also a large/sustained release of LH. Pretreatment with FLA-63 had no effect on the nor-BNI induced increase in basal pulsatile LH secretion, but completely prevented the occurrence of the large/sustained release of LH. The objective of experiment 2 was to determine whether any change in NE release occurred at the site of nor-BNI perfusion in rats showing this large/sustained increase in plasma LH levels, by measuring in vivo NE release at that site. No significant change in perfusate NE levels was observed during perfusion of the MPOA with nor-BNI alone or in combination with desipramine, a NE reuptake blocker, in rats that showed this type of LH response. These results demonstrate that while NE does not mediate the increase in basal pulsatile LH release produced by nor-BNI perfusion in the MPOA, it is essential for the large/sustained elevation in LH secretion seen in response to blockade of kappa-opioid receptors at this site. This latter type of LH secretory response is not, however, associated with an increase in NE release directly at the site of kappa-opioid receptor blockade in the MPOA in pregnant rats.

Phorbol ester regulation of the gonadotropin-releasing hormone (GnRH) gene in GnRH-secreting cell lines: a molecular basis for species differences

Phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) regulation of the GnRH gene was studied in two mouse GnRH neuronal cell lines, Gn11 and NLT. TPA treatment of NLT cells grown in low serum conditions did not alter endogenous mouse GnRH mRNA levels, indicating that the endogenous mouse gene is not regulated by phorbol esters under these conditions. This result is confirmed in transfection studies in which TPA treatment did not change expression of a mouse GnRH-luciferase reporter gene construct. In contrast, TPA treatment stimulated expression of a human GnRH-luciferase reporter construct, correlating with the expression of the protoon-cogenes c-fos and c-jun. TPA stimulation of the human GnRH gene is mediated by a consensus AP-1 site located at -402 to -396 bp, TGACTCA, which specifically binds c-fos and c-jun in Gn11 and NLT cells and recombinant c-jun in gel mobility shift studies. In contrast, the rodent GnRH genes, when aligned for maximum homology, contain a DNA sequence with a 1-bp difference, TGTCTCA from the human gene. In gel mobility shift studies, this DNA sequence does not form a complex with Gn11 or NLT nuclear extract or with recombinant c-jun. This is the first demonstration of species-specific differences in phorbol ester regulation of GnRH gene transcription and could, in part, explain differences in reproductive function among mammals.

Function of hsa_circ_0006646 as a competing endogenous RNA to promote progression in gastric cancer by regulating the miR-665-HMGB1 axis

Background

Mounting evidences indicate that circular RNAs (circRNAs) are a novel class of non-coding RNAs and play vital roles in the tumorigenesis and aggressiveness including gastric cancer (GC). Nevertheless, the precise functions and underlying mechanisms of circRNAs in GC remain largely unknown.

Methods

The Gene Expression Omnibus (GEO) data set GSE163416 was analyzed to screen the key circRNAs in GC. hsa_circ_0006646 was chosen for further study. GC tissues and matched adjacent normal gastric mucosal epithelial tissues were obtained from the Fourth Hospital of Hebei Medical University. The expressions of hsa_circ_0006646 was detected using quantitative real-time polymerase chain reaction (qRT-PCR). hsa_circ_0006646 was knocked down to identify its effects on GC cells. Bioinformatics algorithms were analyzed to predict the microRNA (miRNAs) potentially sponged by hsa_circ_0006646 and its target genes. Fluorescence in situ hybridization (FISH) was conducted to determine the subcellular location of hsa_circ_0006646 and the predicted miRNA. Then, qRT-PCR, luciferase reporter assay, radioimmunoprecipitation assay, Western blotting, and miRNA rescue experiments were used to confirm the hsa_circ_0006646-related regulatory axis in GC. Cell Counting Kit-8 (CCK-8), colony formation, wound healing, and Transwell experiments were performed to determine the effect of the hsa_circ_0006646-related regulatory axis on GC cells' malignant behaviors in vitro. The xenograft tumor mouse model was established to evaluate the effect of hsa_circ_0006646 in vivo.

Results

hsa_circ_0006646 exhibited a high expression in GC tissues as compared to corresponding adjacent normal gastric mucosal epithelial tissues and its high expression was positively correlated with TNM stage, lymph node invasion and poor prognosis (P<0.05). Knockdown of hsa_circ_0006646 suppressed the proliferation, colony formation, migration, and invasion in GC cells (all P<0.05). hsa_circ_0006646 upregulated high mobility group box 1 (HMGB1) by sponging miR-665 in GC cells (P<0.05). The hsa_circ_0006646-miR-665-HMGB1 axis promoted malignant behaviors and epithelial-mesenchymal transition (EMT) in GC cells by activating the Wnt/β-catenin pathway (P<0.05). The existence of hsa_circ_0006646-miR-665-HMGB1 axis was confirmed in GC specimens (P<0.05). Consequently, down-regulated hsa_circ_0006646 inhibited the progression and EMT of GC cells in vivo (P<0.05).

Conclusions

For the first time, we demonstrated that hsa_circ_0006646-miR-665-HMGB1 axis exerted its tumor-promoting effects in GC, which suggested that hsa_circ_0006646 could be potentially targeted for GC treatment.

C1ql4 regulates breast cancer cell stemness and epithelial-mesenchymal transition through PI3K/AKT/NF-κB signaling pathway

Background

The stemness characteristic of breast cancer (BC) is a crucial factor underlying cancer recurrence and metastasis after operative therapy and chemoradiotherapy. Understanding the potential mechanism of breast cancer stem cells (BCSCs) may ameliorate the prognosis of patients.

Methods

We collected clinical specimens of BC patients for staining and statistical analysis to verify the expression status and clinical significance of complement C1q-like 4 (C1ql4). Western blot and qRT-PCR were employed to detect the expression of molecules. Flow cytometry was used to examine cell cycle, cell apoptosis and the portion of BCSCs. Wound healing and Transwell assays were used to detect cell metastasis. The effect of C1ql4 on breast cancer progression in vivo was examined in a nude mouse tumor bearing model.

Results

Our clinical analysis showed that C1ql4 was highly expressed in BC tissues and cell lines, and the high expression of C1ql4 was significantly corelated with the malignancy of BC patients. Moreover, we also found that C1ql4 was overexpressed in BCSCs. C1ql4 knockdown suppressed the BCSC and EMT properties, promoted cell cycle progression, enhanced BC cell apoptosis, and inhibited cell migration and invasion, whereas the C1ql4 overexpression exhibited the opposite effects. Mechanistically, C1ql4 promoted the activation and nuclear location of NF-κB and the expression of downstream factors TNF-α and IL-1β. Moreover, inhibition of PI3K/AKT signaling suppressed the C1ql4-induced stemness and EMT.

Conclusions

Our findings suggest that C1ql4 promotes the BC cell stemness and EMT via modulating the PI3K/AKT/NF-κB signaling, and provides a promising target for BC treatment.

Ceruloplasmin is associated with the infiltration of immune cells and acts as a prognostic biomarker in patients suffering from glioma

Glioma is regarded as a prevalent form of cancer that affects the Central Nervous System (CNS), with an aggressive growth pattern and a low clinical cure rate. Despite the advancement of the treatment strategy of surgical resection, chemoradiotherapy and immunotherapy in the last decade, the clinical outcome is still grim, which is ascribed to the low immunogenicity and tumor microenvironment (TME) of glioma. The multifunctional molecule, called ceruloplasmin (CP) is involved in iron metabolism. Its expression pattern, prognostic significance, and association with the immune cells in gliomas have not been thoroughly investigated. Studies using a variety of databases, including Chinese Glioma Genome Atlas (CGGA), The Cancer Genome Atlas (TCGA), and Gliovis, showed that the mRNA and protein expression levels of CP in patients suffering from glioma increased significantly with an increasing glioma grade. Kaplan-Meier (KM) curves and statistical tests highlighted a significant reduction in survival time of patients with elevated CP expression levels. According to Cox regression analysis, CP can be utilized as a stand-alone predictive biomarker in patients suffering from glioma. A significant association between CP expression and numerous immune-related pathways was found after analyzing the data using the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). Tumor Immune Estimation Resource (TIMER) and CIBERSORT analyses indicated a substantial correlation between the CP expression and infiltration of immunocytes in the TME. Additionally, immune checkpoints and CP expression in gliomas showed a favorable correlation. According to these results, patients with glioma have better prognoses and levels of tumor immune cell infiltration when their CP expression is low. As a result, CP could be used as a probable therapeutic target for gliomas and potentially anticipate the effectiveness of immunotherapy.

[Effect of SLC7A11 gene downregulation on the gefitinib resistance of lung adenocarcinoma PC9/GR cells and its mechanism]

Objective: To screen the key genes involved in gefitinib resistance of lung adenocarcinoma PC9/GR cells which harbored 19 exon mutation of epidermal growth factor receptor (EGFR) gene, and discuss the effect and mechanism of downregulation of solute carrier family 7 member 11 (SLC7A11) on the gefitinib resistance of PC9/GR cells. Methods: RNA microarray was conducted to detect the gene expressions in PC9 and PC9/GR cells. The differently expressed genes were screened by using limma package of R language and analyzed by Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. Western blotting was performed to determine the expression of SLC7A11 protein in PC9 and PC9/GR cells. PC9/GR cells were infected with lentivirus plasmid containing short hairpin RNA (shRNA) targeting SLC7A11 or negative control shRNA (sh-NC), respectively. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the efficacy of shRNA on the expression of SLC7A11 mRNA. Cell counting kit-8 (CCK-8) assay was conducted to determine the suppressing effect of gefitinib on PC9/GR cells. Mito-Tracker Red CMXRos probe and malondialdehyde (MDA) assay kit were used to evaluate gefitinib-induced ferroptosis in PC9/GR cells. Immunohistochemistry (IHC) was conducted to detect the expression of SLC7A11 protein in the tumor tissues of advanced stage lung adenocarcinoma patients harboring 19 exon mutation of EGFR gene. Thirty-six advanced stage lung adenocarcinoma patients who received EGFR-tyrosihe kinase inhibitor(TKI) as first-line treatment in Fourth Hospital of Hebei Medical Unviersity were enrolled. Kaplan-Meier survival curve was drawn to analyze the correlation between SLC7A11 expression and progression-free survival (PFS) of the patients. Results: RNA array demonstrated that 2 888 genes were differently expressed between PC9 and PC9/GR cells. KEGG analysis showed that ferroptosis-related gene was one of the most enriched region of the differently expressed genes between PC9 and PC9/GR cells. These ferroptosis-related gene cohort contained 13 genes, among which SLC7A11 exhibited the most significant difference. Western blotting showed that the expression of SLC7A11 protein in PC9/GR cells was significantly higher than that in PC9 cells (0.76±0.03 vs. 0.19±0.02, P<0.001). The 50% inhibiting concentration (IC(50)) of gefitinib was 35.08 μmol/L and 64.01 μmol/L for sh-SLC7A11 and sh-NC group PC9/GR cells, respectively. PC9/GR cells in sh-SLC7A11 group exhibited significantly lower density of mitochondria fluorescence after gefitinib treatment, compared to the sh-NC group (213.77±26.50 vs. 47.88±4.55, P<0.001). In addition, PC9/GR cells in sh-SLC7A11 group exhibited significantly higher MDA after gefitinib treatment, compared to the sh-NC group [(15.43±1.60) μmol/mg vs. (82.18±7.77) μmol/mg, P<0.001]. The PFS of the patients with low expression of SLC7A11 (n=18) was significantly longer than the patients with high expression of SLC7A11 (n=18, 16.77 months vs. 9.14 months, P<0.001). Conclusion: Downregulation of SLC7A11 could increase the sensitivity of PC9/GR cells to gefitinib by promoting ferroptosis.

NEAT1_1 confers gefitinib resistance in lung adenocarcinoma through promoting AKR1C1-mediated ferroptosis defence

Gefitinib is one of the most extensively utilized epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) for treating advanced lung adenocarcinoma (LUAD) patients harboring EGFR mutation. However, the emergence of drug resistance significantly compromised the clinical efficacy of EGFR-TKIs. Gaining further insights into the molecular mechanisms underlying gefitinib resistance holds promise for developing novel strategies to overcome the resistance and improve the prognosis in LUAD patients. Here, we identified that the inhibitory efficacy of gefitinib on EGFR-mutated LUAD cells was partially dependent on the induction of ferroptosis, and ferroptosis protection resulted in gefitinib resistance. Among the ferroptosis suppressors, aldo-keto reductase family 1 member C1 (AKR1C1) exhibited significant upregulation in gefitinib-resistant strains of LUAD cells and predicted poor progression-free survival (PFS) and overall survival (OS) of LUAD patients who received first-generation EGFR-TKI treatment. Knockdown of AKR1C1 partially reversed drug resistance by re-sensitizing the LUAD cells to gefitinib-mediated ferroptosis. The decreased expression of miR-338-3p contributed to the aberrant upregulation of AKR1C1 in gefitinib-resistant LUAD cells. Furthermore, upregulated long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1_1 (NEAT1_1) sponged miR-338-3p to neutralize its suppression on AKR1C1. Dual-luciferase reporter assay and miRNA rescue experiment confirmed the NEAT1_1/miR-338-3p/AKR1C1 axis in EGFR-mutated LUAD cells. Gain- and loss-of-function assays demonstrated that the NEAT1_1/miR-338-3p/AKR1C1 axis promoted gefitinib resistance, proliferation, migration, and invasion in LUAD cells. This study reveals the effects of NEAT1_1/miR-338-3p/AKR1C1 axis-mediated ferroptosis defence in gefitinib resistance in LUAD. Thus, targeting NEAT1_1/miR-338-3p/AKR1C1 axis might be a novel strategy for overcoming gefitinib resistance in LUAD harboring EGFR mutation.

Circular RNA hsa_circ_0002938 (circCRIM1) promotes the progression of esophageal squamous cell carcinoma by upregulating transcription factor 12

Growing evidence has indicated that circular RNAs (circRNAs) play crucial roles in the tumorigenesis and progression of diverse malignancies. However, the majority of circRNAs involved in esophageal squamous cell carcinoma (ESCC) remain undefined and the exact functions and underlying mechanisms of circRNAs in ESCC still need further exploration. In this study, we identified a novel onco-circRNA hsa_circ_0002938, derived from the exons of cysteine-rich transmembrane BMP regulator 1 (CRIM1) pre-mRNA, referred to as circCRIM1. We found that the expression of circCRIM1 was higher in ESCC tissues, compared to para-carcinoma tissues. Increased expression of circCRIM1 was positively correlated with clinical parameters of ESCC patients including tumor-node-metastasis (TNM) stage, tumor invasion range, and lymph node metastasis. Functionally, the results from the experiments in vitro showed that the knockdown of circCRIM1 suppressed proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in ESCC cells. By conducting bioinformatics algorithms analyses and microRNA (miRNA) rescue experiments, we found that circCRIM1 could act as a competing endogenous RNA (ceRNA) to sponge miR-342-3p in ESCC cells, and thereby upregulated the expression of transcription factor 12 (TCF12), a key regulator promoting the EMT process. Taken together, circCRIM1 facilitates the progression of ESCC by sponging miR-342-3p to regulate TCF12 and promote EMT, and the circCRIM1/miR-342-3p/TCF12 axis may be regarded as a potential predictive biomarker and therapeutic target for treating ESCC.

circNOX4 activates an inflammatory fibroblast niche to promote tumor growth and metastasis in NSCLC via FAP/IL-6 axis

BACKGROUND

Cancer-associated fibroblasts (CAFs) orchestrate a supportive niche that fuels cancer metastatic development in non-small cell lung cancer (NSCLC). Due to the heterogeneity and plasticity of CAFs, manipulating the activated phenotype of fibroblasts is a promising strategy for cancer therapy. However, the underlying mechanisms of fibroblast activation and phenotype switching that drive metastasis remain elusive.

METHODS

The clinical implications of fibroblast activation protein (FAP)-positive CAFs (FAP+CAFs) were evaluated based on tumor specimens from NSCLC patients and bioinformatic analysis of online databases. CAF-specific circular RNAs (circRNAs) were screened by circRNA microarrays of primary human CAFs and matched normal fibroblasts (NFs). Survival analyses were performed to assess the prognostic value of circNOX4 in NSCLC clinical samples. The biological effects of circNOX4 were investigated by gain- and loss-of-function experiments in vitro and in vivo. Fluorescence in situ hybridization, luciferase reporter assays, RNA immunoprecipitation, and miRNA rescue experiments were conducted to elucidate the underlying mechanisms of fibroblast activation. Cytokine antibody array, transwell coculture system, and enzyme-linked immunosorbent assay (ELISA) were performed to investigate the downstream effectors that promote cancer metastasis.

RESULTS

FAP+CAFs were significantly enriched in metastatic cancer samples, and their higher abundance was correlated with the worse overall survival in NSCLC patients. A novel CAF-specific circRNA, circNOX4 (hsa_circ_0023988), evoked the phenotypic transition from NFs into CAFs and promoted the migration and invasion of NSCLC in vitro and in vivo. Clinically, circNOX4 correlated with the poor prognosis of advanced NSCLC patients. Mechanistically, circNOX4 upregulated FAP by sponging miR-329-5p, which led to fibroblast activation. Furthermore, the circNOX4/miR-329-5p/FAP axis activated an inflammatory fibroblast niche by preferentially inducing interleukin-6 (IL-6) and eventually promoting NSCLC progression. Disruption of the intercellular circNOX4/IL-6 axis significantly suppressed tumor growth and metastatic colonization in vivo.

CONCLUSIONS

Our study reveals a role of the circRNA-induced fibroblast niche in tumor metastasis and highlights that targeting the circNOX4/FAP/IL-6 axis is a promising strategy for the intervention of NSCLC metastasis.

Flaxseed Oil Alleviates PFOS-Induced Liver Injury by Regulating Hepatic Cholesterol Metabolism

Perfluorooctanesulfonate (PFOS) is a widespread, persistent environmental pollutant that exerts apparent liver toxicity. Flaxseed oil (FO), a dietary oil rich in α-linolenic acid, has been demonstrated to possess a diverse array of health benefits. However, whether FO protects against PFOS-induced liver injury and its underlying mechanisms remain unclear. C57/BL6 mice were orally treated with different concentrations of FO alone or in combination with 10 mg/kg of PFOS for 28 consecutive days. Blood and liver tissues were collected for proteomic, histopathological, biochemical, immunohistochemical, and molecular examinations. Results demonstrated that FO supplementation reduced PFOS-induced liver injury, as evidenced by a decrease in histopathological changes, serum transaminase (ALT and AST) levels, levels of oxidative stress, and inflammatory cytokine (TNF-α, IL-1β, and IL-6) levels. Proteomic analyses showed that differentially expressed proteins were enriched in cholesterol metabolic pathways when comparing the PFOS group to the FO supplementation groups. The expression of cholesterol metabolism-related proteins was also subsequently measured, revealing that FO supplementation decreased the protein expressions of SREBP2, HMGCR, and LDLR while increasing the expression of CYP7A1. This study demonstrates that FO can alleviate PFOS-induced hepatotoxicity by regulating hepatic cholesterol metabolism, indicating that FO may serve as an effective dietary intervention for preventing liver injury caused by PFOS.

Screening of Differentially Expressed Genes Based on the ACRG Molecular Subtypes of Gastric Cancer and the Significance and Mechanism of AGTR1 Gene Expression

BACKGROUND

The Asian Cancer Research Group (ACRG) classification is a molecular classification established based on the tissues of gastric cancer (GC) patients in Asia. Patients with different ACRG subtypes differ significantly with regard to treatment response and prognosis, which indicates that the ACRG molecular classification is more valuable than the traditional pathological classification. However, the specific differentially expressed genes (DEGs) and the value of the ACRG molecular subtypes of GC have not been studied in depth.

METHODS

Through the analysis of the GEO database, the DEGs in GC tissues of different ACRG molecular subtypes were investigated. The expression and mechanism of the screened angiotensin II receptor type 1 (AGTR1) gene were bioinformatically analyzed and experimentally verified. The role of AGTR1 in GC cells was mainly investigated using CCK-8, wound-healing, transwell invasion assays, qRT-PCR, and Western blotting.

RESULTS

The bioinformatics results showed the presence of multiple DEGs in GC tissues with different ACRG molecular subtypes. Certain DEGs in GC tissues of different ACRG molecular subtypes have prognostic significance. AGTR1 levels in tumor tissues were significantly higher than in paired paracancerous tissues. The prognosis of GC patients with high expression of AGTR1 was poor (p < 0.05). The AGTR1 gene in GC samples was associated with the expression of immune pathways and immune checkpoint genes. After modifying AGTR1 expression in cell lines, cells' proliferation, invasion, and migration abilities and the expression of related genes changed.

CONCLUSIONS

There were significant DEGs in GC tissues with different ACGR molecular types, among which the increased expression of AGTR1 was a molecular feature of MSS/EMT type gastric cancer. Further study found that AGTR1 was closely related to tumor immune infiltration and invasion and may be a new therapeutic target gene for gastric cancer.