RPS15A promotes gastric cancer progression via activation of the Akt/IKK-β/NF-κB signalling pathway

LAIR1 promotes hepatocellular carcinoma cell metastasis and induces M2-macrophage infiltration through activating AKT-IKKβ-p65 axis

LAIR1, a receptor found on immune cells, is capable of binding to collagen and is involved in immune-related diseases. However, the precise contribution of LAIR1 expressed on hepatocellular carcinoma (HCC) cells to tumor microenvironment is still unclear. In our study, bioinformatics analysis and immunofluorescence were employed to study the correlation between LAIR1 levels and clinical indicators. Transwell and scratch tests were used to evaluate how LAIR1 affected the migration and invasion of HCC cells. The chemotactic capacity and alternative activation of macrophages were investigated using RT-qPCR, transwell, and immunofluorescence. To investigate the molecular mechanisms, transcriptome sequencing analysis, Western blot, nucleus/cytoplasm fractionation, ELISA, and cytokine microarray were employed. We revealed a significant correlation between the presence of LAIR1 and an unfavorable outcome in HCC. We indicated that LAIR1 promoted migration and invasion of HCC cells through the AKT-IKKβ-p65 axis. Additionally, the alternative activation and infiltration of tumor-associated macrophages induced by LAIR1 were reliant on the upregulation of IL6 and CCL5 within this axis, respectively. In conclusion, blocking LAIR1 was found to be an effective approach in combating the cancerous advancement of HCC.

Dexmedetomidine Protects Cortical Neurons from Propofol-Induced Apoptosis via Activation of Akt-IKK-NF-κB Signaling Pathway by α2A-adrenoceptor

CONTEXT

Propofol can induce neuroapoptosis. It has been reported that dexmedetomidine (DEX) has a protective effect on propofol-induced neuroapoptosis, but the specific mechanism needs to be further explored to provide a theoretical basis for their combined use.

OBJECTIVE

We aimed to explore the neuroprotective effect of DEX on primary cortical neurons treated by propofol and to elucidate the underlying mechanistic pathways.

METHODS

Cortical neurons were isolated from fetal rats and treated with propofol. MTT assays were performed to detect cell viability, α-tubulin immunofluorescent assays were conducted to observe cell abnormalities, and c-caspase3 immunofluorescent assays and flow cytometry were performed to examine cell apoptosis. Further, neurons were cotreated with propofol and DEX to study DEX's neuroprotective effects on propofol-caused neuronal injuries. Finally, the α2A-adrenoceptor was knocked out and/or the Akt activator (SC-79) was added to cells co-treated with propofol and DEX. The expression levels of Akt-IKK-NF-κB pathway-related proteins were detected by western blot.

RESULTS

Propofol decreased cell viability in a dose-dependent manner, triggered apoptosis, caused morphological abnormalities and down-regulated the phosphorylation levels of Akt, IKK, NF-κB and IκB in cortical neurons. DEX ameliorated the decrease of cell viability, alleviated neuronal apoptosis and promoted the downregulated expression levels of p-Akt, IKK, NF-κB, and IκB proteins which had been induced by propofol treatment. Western blot findings following the transfection of α2A-siRNA and the addition of SC-79 suggested that DEX's neuroprotective functions arose from the stimulation of α2A-adrenoceptors to activate the Akt-IKK-NF-κB signal pathway.

CONCLUSION

DEX protected neurons against propofol-induced apoptosis via activation of the Akt-IKK-NF-κB signal pathway through α2A-adrenoceptors.

Chemo-small extracellular vesicles released in cisplatin-resistance ovarian cancer cells are regulated by the lysosomal function

Chemoresistance is a common problem in ovarian cancer (OvCa) treatment, where resistant cells, in response to chemotherapy, secrete small extracellular vesicles (sEVs), known as chemo-sEVs, that transfer resistance to recipient cells. sEVs are formed as intraluminal vesicles (ILVs) within multivesicular endosomes (MVEs), whose trafficking is regulated by Ras-associated binding (RAB) GTPases that mediate sEVs secretion or lysosomal degradation. A decrease in lysosomal function can promote sEVs secretion, but the relationship between MVEs trafficking pathways and sEVs secretion in OvCa chemoresistance is unclear. Here, we show that A2780cis cisplatin (CCDP) resistant OvCa cells had an increased number of MVEs and ILVs structures, higher levels of Endosomal Sorting Complex Required for Transport (ESCRTs) machinery components, and RAB27A compared to A2780 CDDP-sensitive OvCa cells. CDDP promoted the secretion of chemo-sEVs in A2780cis cells, enriched in DNA damage response proteins. A2780cis cells exhibited poor lysosomal function with reduced levels of RAB7, essential in MVEs-Lysosomal trafficking. The silencing of RAB27A in A2780cis cells prevents the Chemo-EVs secretion, reduces its chemoresistance and restores lysosomal function and levels of RAB7, switching them into an A2780-like cellular phenotype. Enhancing lysosomal function with rapamycin reduced chemo-sEVs secretion. Our results suggest that adjusting the balance between secretory MVEs and lysosomal MVEs trafficking could be a promising strategy for overcoming CDDP chemoresistance in OvCa.

Targeted Sequencing in Gastric Cancer: Association with Tumor Molecular Characteristics and FLOT Therapy Effectiveness

Heterogeneity of gastric cancer (GC) is the main trigger of the disease's relapse. The aim of this study was to investigate the connections between targeted genes, cancer clinical features, and the effectiveness of FLOT chemotherapy. Twenty-one patients with gastric cancers (GCs) were included in this study. Tumor-targeted sequencing was conducted, and real-time PCR was used to assess the expression of molecular markers in tumors. Seven patients with stabilization had mutations that were related to their response to therapy and were relevant to the tumor phenotype. Two patients had two mutations. The number of patients with TP53 mutations increased in HER2-positive tumor status. PD-L1-positive cancers had mutations in KRAS, TP53, PIK3CA, PTEN, and ERBB, which resulted in an increase in PD-1 expression. TP53 mutation and PTEN mutation are associated with changes in factors associated with neoangiogenesis. In concusion, patients who did not have aggressive growth markers that were verified by molecular features had the best response to treatment, including complete morphologic regression.

Cell division cycle 42 effector protein 4 inhibits prostate cancer progression by suppressing ERK signaling pathway

Prostate cancer (PCa) is the most common malignancy among men worldwide. The cell division cycle 42 effector protein 4 (CDC42EP4) functions downstream of CDC42, yet its role and molecular mechanisms in PCa remain unexplored. This study aimed to elucidate the role of CDC42EP4 in the progression of PCa and its underlying mechanisms. Bioinformatical analysis indicated that CDC42EP4 expression was significantly lower in PCa tissue compared to normal prostate tissue. Cellular phenotyping analysis suggested that CDC42EP4 markedly inhibited the proliferation, migration, and invasion of PCa cells. Xenograft tumor assays further demonstrated that CDC42EP4 suppressed the growth of PCa cells in vivo. Mechanistically, the study established that CDC42EP4 inhibited the ERK pathway in PCa cells. Additionally, the ERK pathway inhibitor PD0325901 was employed, revealing that PD0325901 significantly nullified the effects of CDC42EP4 on PCa cell proliferation, migration, and invasion. Collectively, our findings demonstrate that CDC42EP4 acts as a critical tumor suppressor gene, inhibiting PCa cell proliferation, migration, and invasion through the ERK pathway, thereby presenting potential targets for PCa therapy.

In Vivo Investigation of the Effect of Dietary Acrylamide and Evaluation of Its Clinical Relevance in Colon Cancer

Dietary exposure to acrylamide (AA) has been linked with carcinogenicity in the gastrointestinal (GI) tract. However, epidemiologic data on AA intake in relation to cancer risk are limited and contradictory, while the potential cancer-inducing molecular pathways following AA exposure remain elusive. In this study, we collected mechanistic information regarding the induction of carcinogenesis by dietary AA in the colon, using an established animal model. Male Balb/c mice received AA orally (0.1 mg/kg/day) daily for 4 weeks. RNA was extracted from colon tissue samples, followed by RNA sequencing. Comparative transcriptomic analysis between AA and mock-treated groups revealed a set of differentially expressed genes (DEGs) that were further processed using different databases through the STRING-DB portal, to reveal deregulated protein-protein interaction networks. We found that genes implicated in RNA metabolism, processing and formation of the ribosomal subunits and protein translation and metabolism are upregulated in AA-exposed colon tissue; these genes were also overexpressed in human colon adenocarcinoma samples and were negatively correlated with patient overall survival (OS), based on publicly available datasets. Further investigation of the potential role of these genes during the early stages of colon carcinogenesis may shed light into the underlying mechanisms induced by dietary AA exposure.

MicroRNA-147b induces neuroendocrine differentiation of prostate cancer cells by targeting ribosomal protein RPS15A

BACKGROUND

Prostate cancer (PCa) is the leading cause of cancer related deaths in men, often androgen deprivation therapy (ADT) leads to the progression of androgen independent PCa (AIPC) which further leads to Neuroendocrine PCa (NEPC). Identifying the molecular mechanisms which navigate the neuroendocrine differentiation (NED) of PCa cells is clinically relevant. It has been suggested that the micro RNAs (miRNAs) play an important role in the regulation of intrinsic mechanisms relevant to tumor progression, resistance as a result leads to poor prognosis. miR-147b has been transpiring as one of the deregulated miRNAs associated with the occurrence of multiple cancers. The present study has studied the role of miRNA-147b in inducing NEPC.

METHODS

To investigate the functional role of miR-147b in NEPC, we have expressed miRNA mimics or inhibitors in PCa cells and monitored the progression of NEPC along with PCa cell proliferation and survival. The molecular mechanism miRNA-147b follows was studied using western blot and reverse transcription polymerase chain analysis. miRNA target prediction using bioinformatics tools followed by target validation using luciferase reporter assays was performed.

RESULTS

In the present study, we found that miR-147b is highly expressed in AIPC cell lines in particular neuroendocrine cells NCI-H660 and NE-LNCaP derived from LNCaP. Mechanistic studies revealed that overexpression of miR-147b or miRNA mimics induced NED in LNCaP cells in in-vitro while its inhibitor reversed the NE features (increased NE markers and reduced prostate specific antigen) of PC3, NCI-H660 and NE-LNCaP cells. In addition, miR-147b reduced the proliferation rate of LNCaP cells via elevated p27kip1 and lowered cyclin D1 for promoting differentiation. In reporter assays, we have identified ribosomal protein S15A (RPS15A) is a direct target of miRNA-147b and RPS15A expression was negatively regulated by miR-147b in PCa cells. Furthermore, we also report that RPS15A is downregulated in NEPC cells and its expression is inversely correlated with NE markers.

CONCLUSION

Targeting the miR-147b - RPS15A axis may overcome the progression of NEPC and serve as a novel therapeutic target to attenuate NED progression of PCa.

Identifying the Common Cell-Free DNA Biomarkers across Seven Major Cancer Types

Blood-based detection of circulating cell-free DNA (cfDNA) is a non-invasive and easily accessible method for early cancer detection. Despite the extensive utility of cfDNA, there are still many challenges to developing clinical biomarkers. For example, cfDNA with genetic alterations often composes a small portion of the DNA circulating in plasma, which can be confounded by cfDNA contributed by normal cells. Therefore, filtering out the potential false-positive cfDNA mutations from healthy populations will be important for cancer-based biomarkers. Additionally, many low-frequency genetic alterations are easily overlooked in a small number of cfDNA-based cancer tests. We hypothesize that the combination of diverse types of cancer studies on cfDNA will provide us with a new perspective on the identification of low-frequency genetic variants across cancer types for promoting early diagnosis. By building a standardized computational pipeline for 1358 cfDNA samples across seven cancer types, we prioritized 129 shard genetic variants in the major cancer types. Further functional analysis of the 129 variants found that they are mainly enriched in ribosome pathways such as cotranslational protein targeting the membrane, some of which are tumour suppressors, oncogenes, and genes related to cancer initiation. In summary, our integrative analysis revealed the important roles of ribosome proteins as common biomarkers in early cancer diagnosis.

eIF3 mRNA selectivity profiling reveals eIF3k as a cancer-relevant regulator of ribosome content

eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA-selective functions of individual subunits remain poorly defined. Using multiomic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo-complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5'-UTR of RSP15A mRNA negated them. eIF3k and eIF3l are selectively downregulated in response to endoplasmic reticulum and oxidative stress. Supported by mathematical modeling, our data uncover eIF3k-l as a mRNA-specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content, possibly to secure spare translational capacity that can be mobilized during stress.

Taurochenodeoxycholic acid reduces astrocytic neuroinflammation and alleviates experimental autoimmune encephalomyelitis in mice

OBJECTIVE

Multiple sclerosis (MS) is an immune regulatory disease that affects the central nervous system (CNS). The main pathological features include demyelination and neurodegeneration, and the pathogenesis is associated with astrocytic neuroinflammation. Taurochenodeoxycholic acid (TCDCA) is one of the conjugated bile acids in animal bile, and it is not clear whether TCDCA could improve MS by inhibiting the activation of astrocytes. This study was aimed to evaluate the effects of TCDCA on experimental autoimmune encephalomyelitis (EAE)-a classical animal model of MS, and to probe its mechanism from the aspect of suppressing astrocytic neuroinflammation. It is expected to prompt the potential application of TCDCA for the treatment of MS.

RESULTS

TCDCA effectively alleviated the progression of EAE and improved the impaired neurobehavior in mice. It mitigated the hyperactivation of astrocytes and down-regulated the mRNA expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in the brain cortex. In the C6 astrocytic cell line induced by lipopolysaccharide (LPS), TCDCA treatment dose-dependently decreased the production of NO and the protein expression of iNOS and glial fibrillary acidic protein (GFAP). TCDCA consistently inhibited the mRNA expressions of COX2, iNOS and other inflammatory mediators. Furthermore, TCDCA decreased the protein expression of phosphorylated serine/threonine kinase (AKT), inhibitor of NFκB α (IκBα) and nuclear factor κB (NFκB). And TCDCA also inhibited the nuclear translocation of NFκB. Conversely, as an inhibitor of the G-protein coupled bile acid receptor Gpbar1 (TGR5), triamterene eliminated the effects of TCDCA in LPS-stimulated C6 cells.

CONCLUSION

TCDCA improves the progress of EAE by inhibiting the astrocytic neuroinflammation, which might be exerted by the regulation of TGR5 mediated AKT/NFκB signaling pathway. These findings may prompt the potential application of TCDCA for MS therapy by suppressing astrocyte inflammation.

FOXN3 inhibits the progression of ovarian cancer through negatively regulating the expression of RPS15A

Ovarian cancer is the second most common cause of gynecological cancer death and has a high recurrence rate. FOXN3, a transcription inhibitor belonging to FOX family, has anti-tumor effects on several cancers. Bioinformatics analysis revealed that the expression of FOXN3 was downregulated in ovarian cancer specimens. However, the role of FOXN3 in ovarian cancer remains unclear. Herein, we investigated the role of FOXN3 in ovarian cancer using OVCAR3 and A2780 cells. Flow cytometry and CCK-8 analysis showed that overexpression of FOXN3 inhibited the proliferation and cell cycle progression of OVCAR3 cells. Cell invasion and migration abilities were decreased by FOXN3 according to transwell and wound healing assays. The suppression of FOXN3 on angiogenesis in OVCAR3 cells was evidenced by reduced vessel formation and VEGFA protein expression. Taken together, FOXN3 had an inhibitory effect on the proliferation, migration, invasion and angiogenesis of OVCAR3 cells, while its knockdown exhibited an opposite effect in A2780 cells. By inoculation of FOXN3-overexpressing cells into nude mice, tumorigenesis assay demonstrated that FOXN3 could delay the growth of ovarian cancer cells in vivo. The interaction between FOXN3 and RPS15A was preliminarily explored via dual-luciferases assay and ChIP. FOXN3 was confirmed to bind to the promoter (at - 1588/- 1581 and - 1476/- 1467) of gene RPS15A and inhibit its transcriptional expression. We further found that overexpression of RPS15A diminished the inhibition of FOXN3 on ovarian cancer cell malignant behaviors. These findings indicate that FOXN3 negatively regulates the expression of RPS15A and thus suppresses the progression of ovarian cancer.

METTL13 facilitates cell growth and metastasis in gastric cancer via an eEF1A/HN1L positive feedback circuit

Although improved treatment could inhibit progression of gastric cancer (GC), the recurrence and metastasis remain challenging issues. Methyltransferase like 13 (METTL13) has been implicated in most human cancers, but its function and mechanism in GC remain elusive. In the present study, we evaluated its expression in GC samples and found it was aberrantly overexpressed in cancer tissues than that in normal stomach tissues. High expression of METTL13 was closely associated with age, tumor size and T classification. Biological experiments showed that silencing METTL13 suppressed gastric cancer cell proliferation and metastasis in vivo and vitro, whereas opposite effects were observed upon METTL13 overexpression. Further mechanistic explorations revealed that METTL13 regulated the expression of HN1L (Hematological and neurological expressed 1-like), which is reported to be an oncogene in various cancers. Knockdown of HN1L dampened gastric cancer cell growth induced by METTL13. Eukaryotic translation elongation factor-1A (eEF1A), the present sole methylation substrate of METTL13, was involved in the regulation of HN1L by METTL13 in a K55 methylation independent manner. In addition, we also found HN1L could facilitate METTL13 expression in GC cells consistent with a previous report in hepatocellular carcinoma. Thus, these findings demonstrate a METTL13/eEF1A/HN1L positive feedback circuit promoting gastric cancer development and metastasis. It will help develop promising diagnostic and therapeutic targets for this disease.

Tumor-promoting properties of enolase-phosphatase 1 in breast cancer via activating the NF-κB signaling pathway

BACKGROUND

Evidence suggests that enolase-phosphatase 1 (ENOPH1) is involved in the progression of some certain types of cancers and acts as an oncogenic factor in tumor progression. The present study aimed to identify the central role of ENOPH1 in the progression of breast cancer (BC), a highly proliferative and aggressive disease.

METHODS AND RESULTS

ENOPH1 expression in BC tissues was explored based on the online resource and 40 paired fresh BC and para-carcinoma samples. Functional assays were performed to evaluate the biological effect of ENOPH1 on cell proliferation and migration in ENOPH1-silenced or overexpressing BC cell lines. Blockade of NF-κB by BAY11-7082 was performed to evaluate whether ENOPH1 exerted tumor-promoting properties via regulating the NF-κB signaling pathway. Results of the present study demonstrated that ENOPH1 expression was profoundly upregulated in BC tissues compared with adjacent breast tissues, and ENOPH1 expression was associated with cancer stage, node metastasis status, and overall survival. Functional assays demonstrated that ENOPH1 overexpression significantly accelerated BC cell proliferation, migration, and invasion, while genetic knockdown of ENOPH1 yielded the opposite effects. Mechanistically, ENOPH1 activated the NF-κB pathway, as evidenced by increased expression of NF-κB downstream genes and enhanced NF-κB p65 nuclear translocation. Furthermore, the oncogenic properties of ENOPH1 in proliferation, migration, and invasion were restrained following inhibition of the NF-κB signaling pathway.

CONCLUSIONS

These findings indicated the significance of ENOPH1 in promoting cell proliferation and invasion, mainly through activating the NF-κB pathway, suggesting that ENOPH1 might be an attractive prognostic factor and a potential target for BC therapy.

Efficacy and Mechanism of Quercetin in the Treatment of Experimental Colitis Using Network Pharmacology Analysis

Quercetin, a flavonoid that is present in vegetables and fruits, has been found to have anti-inflammatory effects. However, the mechanism by which it inhibits colitis is uncertain. This study aimed to explore the effect and pharmacological mechanism of quercetin on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC). Mice were given a 4% (w/v) DSS solution to drink for 7 days, followed by regular water for the following 5 days. Pharmacological mechanisms were predicted by network pharmacology. High-throughput 16S rDNA sequencing was performed to detect changes in the intestinal microbiota composition. Enzyme-linked immunosorbent assay and western blotting were performed to examine the anti-inflammatory role of quercetin in the colon. Quercetin attenuated DSS-induced body weight loss, colon length shortening, and pathological damage to the colon. Quercetin administration modulated the composition of the intestinal microbiota in DSS-induced mice and inhibited the growth of harmful bacteria. Network pharmacology revealed that quercetin target genes were enriched in inflammatory and neoplastic processes. Quercetin dramatically inhibited the expression of phosphorylated protein kinase B (AKT) and phosphatidylinositol 3-kinase (PI3K). Quercetin has a role in the treatment of UC, with pharmacological mechanisms that involve regulation of the intestinal microbiota, re-establishment of healthy microbiomes that favor mucosal healing, and the inhibition of PI3K/AKT signaling.

RNA binding motif protein 3 (RBM3) promotes protein kinase B (AKT) activation to enhance glucose metabolism and reduce apoptosis in skeletal muscle of mice under acute cold exposure

The main danger of cold stress to animals in cold regions is systemic metabolic changes and protein synthesis inhibition. RBM3, an exceptional cold shock protein, is rapidly upregulated in response to hypothermia to resist the adverse effects of cold stress. However, the mechanism of the protective effect and the rapid upregulation of RBM3 remains unclear. O-GlcNAcylation, an atypical O-glycosylation, is precisely regulated only by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) and participates in the signal transduction of multiple cellular stress responses as a "stress and nutrition receptor." Therefore, our study aimed to explore the mechanism of RBM3 regulating glucose metabolism and promoting survival in skeletal muscle under acute cold exposure. Meanwhile, our study verifies whether O-GlcNAcylation mediated by OGT rapidly upregulates RBM3. The blood and skeletal muscle of mice were collected at the end of cold exposure treatment for 0, 2, and 4 h. Changes in levels of RBM3, AKT, glycolysis apoptosis, and OGT were measured. The results show that acute cold exposure upregulated RBM3, OGT, and AKT phosphorylation and increased energy consumption, which enhanced glycolysis and prevent apoptosis. In the 32 °C mild hypothermia model in vitro, overexpression of RBM3 enhanced AKT phosphorylation. Meanwhile, inactivation of AKT by wortmannin resulted in increased apoptosis and decreased glucose metabolism in skeletal muscle under acute cold exposure. In addition, OGT-mediated O-GlcNAcylation of p65 was confirmed in mouse myoblast cell line (C2C12) cells at mild hypothermia. O-GlcNAcylation level affected p65 activity and nuclear translocation. Compared with wild type (WT) mice, RBM3 and p65 phosphorylation were decreased in specific skeletal muscle Ogt (KO) mice, whereas AKT phosphorylation, glycolysis, and apoptosis were increased. Taken together, O-GlcNAcylation of p65 upregulates RBM3 to promote AKT phosphorylation, enhance glucose metabolism, and reduce apoptosis in skeletal muscle of mice under acute cold exposure.

RPS3 Promotes the Metastasis and Cisplatin Resistance of Adenoid Cystic Carcinoma

Background

Adenoid cystic carcinoma (ACC) is a malignant tumor in salivary gland tissue, that is characterized by strong invasiveness and lung metastasis, leading to poor survival rates. RPS3 is been reported to be associated with the biological functions of tumor cells. This study explored the regulatory effect of RPS3 in ACC to provide new therapeutic targets for ACC therapy.

Methods

We reviewed the clinical and pathologic data of 73 ACC patients. The expression of RPS3 was examined in ACC by immunohistochemistry. Transwell, wound healing, half-maximal inhibitory concentration (IC50) and other experiments were used to determine the regulatory effect of RPS3 on ACC functions. Coimmunoprecipitation and mass spectrometry analysis were used to detect the binding proteins of RPS3, mechanisms by which RPS3/STAT1/NF-kB signaling regulates ACC behavior were assessed using western blotting (WB), qPCR, etc. To explore the regulatory effect of RPS3 on ACC in vivo, we constructed nude mouse sciatic nerve infiltration model and a lung metastasis model for studies.

Results

High RPS3 expression was associated with metastasis and a poor prognosis in ACC patients. Inhibition of RPS3 expression reduced ACC migration, invasion and cisplatin resistance, and overexpression of RPS3 promoted ACC migration, invasion and cisplatin resistance. Further experiments revealed that RPS3 can activate the STAT1/NF-kB signaling pathway and regulate ACC behavior through binding to STAT1. The incidence of sciatic nerve infiltration and lung metastasis in nude mice after RPS3 knockdown was lower than that of the control group in vivo.

Conclusion

RPS3 is highly expressed and associated with the prognosis and survival of ACC patients. The RPS3/STAT1/NF-kB pathway may play an important regulatory role in ACC migration, invasion and chemoresistance. As a new therapeutic target of ACC, its clinical application value is worthy of attention and further exploration.

Systemic Analysis of the Anticancer Effects of Sijunzi Decoction on Gastric Cancer Based on Network Pharmacology

Objective:

Sijunzi decoction (SJZD) has been used for alleviating peptic ulcer or gastric discomfort, and treating spleen disorders since the Song Dynasty, but its pharmacological effect on human gastric cancer (GC) is still unclear. In this research, a network pharmacology-based strategy was applied to explore active ingredients, potential targets, and molecular mechanisms of SJZD against GC.

Methods:

The active compounds and potential targets of SJZD, as well as GC-associated gene targets, were retrieved from publicly available databases. Bioinformatics approaches were used to assess the network interaction, functional regulation, and signaling pathways between SJZD ingredients and GC targets. The anticancer effects of SJZD against GC were verified in vivo by a mouse subcutaneous model.

Results:

The results of network analysis showed that quercetin was the most active ingredient in SJZD. Several prominent target genes of SJZD were identified, such as AKT1 and STAT3. Gene ontology analysis revealed that the core anti-GC targets of SJZD included transcription factor activity and kinase activity. Pathway enrichment analysis indicated that GC patients could be benefited from SJZD treatment via modulation of signaling pathways related to endocrine system, cancer, and infectious disease. Furthermore, in vivo experiments showed that high-dose SJZD could inhibit GC xenograft tumor growth, reduce GC cell proliferation, induce GC cell apoptosis, and decrease the expression of p-AKT1 and p-STAT3.

Conclusions:

Taken together, our results suggest that SJZD can serve as an effective adjuvant therapeutic agent for GC patients.

Natural bear bile powder suppresses neuroinflammation in lipopolysaccharide-treated mice via regulating TGR5/AKT/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

According to the Tang Dynasty classics Dietetic Material Medica and the Ming Dynasty classics Compendium of Materia Medica records, bear bile powder (BBP) has been used to treat a variety of diseases, such as febrile seizures, the pathogenesis of which is associated to neuroinflammation. However, the mechanism of BBP on alleviating neuroinflammation remains unclear.

AIMS OF THE STUDY

Microglia can be activated by peripheral lipopolysaccharide (LPS) and play an important role in the pathogenesis of neuroinflammation. The purpose of this study is to investigate the effects and mechanism of BBP in inhibiting LPS-induced microglia inflammation in vitro and in vivo.

MATERIALS AND METHODS

The anti-microglia inflammatory effects and mechanism of BBP were assessed in LPS-treated BV2 microglial cells and in LPS-treated mice. The mRNA expression levels of the inflammatory factor and the protein expressions of cyclooxygenase-2 (COX2), inducible nitric oxide synthase (iNOS), takeda G-protein coupled receptor 5 (TGR5), nuclear factor-κB (NF-κB), inhibitor of NF-κB (IκBɑ), protein kinase B (AKT) in BV2 cells, mouse hippocampus and cortex were detected. The NF-κB transcription activity and NF-κB nuclear translocation were observed.

RESULTS

Our findings showed that BBP reduces branched process retraction and NO in LPS-treated BV2 cells, inhibits the protein expression of ionized calcium binding adaptor molecule 1 in the hippocampus of LPS-treated mice. Moreover, we observed that BBP decreases tumor necrosis factor α, interleukin (IL)-6 and IL-1β mRNA levels, deceases iNOS and COX-2 protein levels, increases TGR5 protein levels, suppresses the phosphorylation of AKT, NF-κB and IκBɑ protein in microglia both in vitro and in vivo. Further, we found that triamterene, the inhibitor of TGR5, abolishes the effects of BBP in LPS- treated BV2 cells.

CONCLUSION

BBP inhibits LPS-induced microglia activation, and the mechanism of its action is partly through TGR5/AKT/NF-κB signaling pathway.

PSMC2 promotes the progression of gastric cancer via induction of RPS15A/mTOR pathway

As one of the most common malignant tumors, it is particularly important to further understand the development mechanism of gastric cancer and to find more effective therapeutic target genes. The results of immunohistochemical staining showed that PSMC2 was upregulated in gastric cancer. Cell function experiments indicated that PSMC2 knockdown inhibited the proliferation, clone formation and migration of gastric cancer cells, and induced apoptosis. In vivo experiments further showed that PSMC2 knockdown suppressed tumor growth. RPS15A and mTOR pathway were identified the downstream gene and pathway of PSMC2 by GeneChip and IPA. PSMC2 knockdown inhibited RPS15A expression and mTOR pathway, which was neutralized by RPS15A overexpression. Overexpression of RPS15A promoted the proliferation and migration of gastric cancer cells, which alleviated the inhibitory effect caused by PSMC2 knockdown to a certain extent. The mTOR pathway inhibitor Torin1 partially restored the promoting role of RPS15A overexpression on the gastric cancer cell proliferation. Furthermore, bioinformatics analysis and dual-luciferase reporter assays showed that PSMC2 and RPS15A competitively bound to hsa-let-7c-3p. Inhibition of hsa-let-7c-3p promoted the migration of MGC-803 cells and reduced the apoptosis level, while simultaneous inhibition PSMC2 and hsa-let-7c-3p restored the migration and apoptosis levels of gastric cancer cells. In conclusion, PSMC2 and RPS15A were highly expressed in gastric cancer. PSMC2 enhanced RPS15A levels by targeting hsa-let-7c-3p, and then activated mTOR pathway, thereby promoting the progression of gastric cancer.

Exosomal miRNA-455 from Bone Marrow Stromal Cells (BMSCs) Promotes Macrophage Phagocytosis and Restrains Progression of Gastric Cancer (GC)

Multiple miRNAs are differentially expressed in gastric cancer (GC). Herein, this study aims to investigate miR-455’s role in GC and its mechanism. Exosomes (exo) separated from BMSCs after transfection were co-cultured with either phagocytes, GC cells (NCI-N87 cell), or macrophages combined with NCI-N87cells (mixed group) followed by analysis of the expression of PTEN, N-cadherin, E-cadherin, and PI3K, and AKT by RT-qPCR and Western blot. Increased miR-455 expression was observed in GC cells upon transfection. GC cells in the mixed group relative to NCI-N87 group exhibited a lower cell migration and invasion and impaired proliferative capacity (p < 0.05), accompanied with higher expressions of N-cadherin, E-cadherin, PI3K, and AKT, and decreased level of PTEN (p < 0.05). The combined treatment resulted in a higher phagocytic rate (12.38±0.21%) and phagocytic index (14.29±2.11%) compared to treatment with only phagocytes (p < 0.05). In conclusion, BMSC-derived exosomal miR-455 inhibits the growth of GC cells and promotes the phagocytosis through inactivating PI3K/AKT signaling pathway.

Airway Basal Cells Mediate Hypoxia-Induced EMT by Increasing Ribosome Biogenesis

Excessive secretion of airway mucus and fluid accumulation are the common features of many respiratory diseases, which, in turn, induce cell hypoxia in the airway epithelium, resulting in epithelial–mesenchymal transition (EMT) and ultimately fibrosis. However, the mechanisms of EMT induced by hypoxia in the airway are currently unclear. To mimic the status of edematous fluid retention in the airway, we cultured primary mouse tracheal epithelial cells (MTECs) in a liquid–liquid interface (LLI) mode after full differentiation in a classic air–liquid interface (ALI) culture system. The cell hypoxia was verified by the physical characteristics and lactate production in cultured medium as well as HIF expression in MTECs cultured by LLI mode. EMT was evidenced and mainly mediated by basal cells, supported by flow cytometry and immunofluorescence assay. The differently expressed genes of basal and other airway epithelial cells were found to be enriched in the ribosome by our analysis of an MTEC single-cell RNA sequencing data set and Myc, the global regulator of ribosome biogenesis was identified to be highly expressed in basal cells. We next separated basal cells from bulk MTECs by flow cytometry, and the real-time PCR results showed that ribosome biogenesis was significantly upregulated in basal cells, whereas the inhibition of ribosome biogenesis alleviated the phosphorylation of the mammalian target of rapamycin/AKT and abrogated hypoxia-induced EMT in MTECs. Collectively, these observations strongly suggest that basal cells in the airway epithelium may mediate the process of hypoxia-induced EMT, partly through enhancing ribosome biogenesis.

Deregulation of ribosomal proteins in human cancers

The ribosome, the site for protein synthesis, is composed of ribosomal RNAs (rRNAs) and ribosomal proteins (RPs). The latter have been shown to have many ribosomal and extraribosomal functions. RPs are implicated in a variety of pathological processes, especially tumorigenesis and cell transformation. In this review, we will focus on the recent advances that shed light on the effects of RPs deregulation in different types of cancer and their roles in regulating the tumor cell fate.

TMED3/RPS15A Axis promotes the development and progression of osteosarcoma

Background

Osteosarcoma is a primary malignant tumor that mainly affects children and young adults. Transmembrane emp24 trafficking protein 3 (TMED3) may be involved in the regulation of malignant cancer behaviors. However, the role of TMED3 in osteosarcoma remains mysterious. In this study, the potential biological function and underlying mechanism of TMED3 in progression of osteosarcoma was elaborated.

Methods

The expression of TMED3 in osteosarcoma was analyzed by immunohistochemical staining. The biological function of TMED3 in osteosarcoma was determined through loss-of-function assays in vitro. The effect of TMED3 downregulation on osteosarcoma was further explored by xenograft tumor model. The molecular mechanism of the regulation of TMED3 on osteosarcoma was determined by gene expression profile analysis.

Results

The expression of TMED3 in osteosarcoma tissues was significantly greater than that in matched adjacent normal tissues. Knockdown of TMED3 inhibited the progression of osteosarcoma by suppressing proliferation, impeding migration and enhancing apoptosis in vitro. We further validated that knockdown of TMED3 inhibited osteosarcoma generation in vivo. Additionally, ribosomal protein S15A (RPS15A) was determined as a potential downstream target for TMED3 involved in the progression of osteosarcoma. Further investigations elucidated that the simultaneous knockdown of RPS15A and TMED3 intensified the inhibitory effects on osteosarcoma cells. Importantly, knockdown of RPS15A alleviated the promotion effects of TMED3 overexpression in osteosarcoma cells.

Conclusions

In summary, these findings emphasized the importance of TMED3/RPS15A axis in promoting tumor progression, which may be a promising candidate for molecular therapy of osteosarcoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02340-w.

miR-654-5p promotes gastric cancer progression via the GPRIN1/NF-κB pathway

Background

Gastric carcinoma (GC) ranks the fifth most common cancer worldwide, with high incidence and mortality rates. Numerous microRNAs (miRNAs), including miR-654-5p, have been implicated in the pathophysiological processes of tumorigenesis. Nevertheless, the mechanism of miR-654-5p in GC is unclear.

Objectives

Our study is devoted to exploring the function and molecular mechanism of miR-654-5p on the malignant cell behaviors of GC.

Methods

The gene expression was detected by reverse transcription quantitative polymerase chain reaction. GC cell proliferation and motion were assessed by colony formation assay and transwell assay. The binding capacity between miR-654-5p and G protein-regulated inducer of neurite outgrowth 1 (GPRIN1) was explored by luciferase reporter and RNA pulldown assays. The protein levels were detected by Western blotting.

Results

miR-654-5p expression was higher in GC cells and tissues than control cells and tissues. miR-654-5p promoted GC cell growth and motion. Moreover, our findings showed that miR-654-5p was bound with GPRIN1. Importantly, downregulation of GPRIN1 rescued the inhibitory influence of miR-654-5p knockdown on GC cell malignant behaviors. Additionally, miR-654-5p activated the nuclear factor kappa-B (NF-κB) pathway by regulation of GPRIN1.

Conclusions

miR-654-5p facilitated cell proliferation, migration, and invasion in GC via targeting the GPRIN1 to activate the NF-κB pathway.

Application of Genetic Algorithm-Based Support Vector Machine in Identification of Gene Expression Signatures for Psoriasis Classification: A Hybrid Model

BACKGROUND

Psoriasis is a chronic autoimmune disease impairing significantly the quality of life of the patient. The diagnosis of the disease is done via a visual inspection of the lesional skin by dermatologists. Classification of psoriasis using gene expression is an important issue for the early and effective treatment of the disease. Therefore, gene expression data and selection of suitable gene signatures are effective sources of information.

METHODS

We aimed to develop a hybrid classifier for the diagnosis of psoriasis based on two machine learning models of the genetic algorithm and support vector machine (SVM). The method also conducts gene signature selection. A publically available gene expression dataset was used to test the model.

RESULTS

A number of 181 probe sets were selected among the original 54,675 probes using the hybrid model with a prediction accuracy of 100% over the test set. A number of 10 hub genes were identified using the protein-protein interaction network. Nine out of 10 identified genes were found in significant modules.

CONCLUSIONS

The results showed that the genetic algorithm improved the SVM classifier performance significantly implying the ability of the proposed model in terms of detecting relevant gene expression signatures as the best features.

Ribosomal proteins and human diseases: molecular mechanisms and targeted therapy

Ribosome biogenesis and protein synthesis are fundamental rate-limiting steps for cell growth and proliferation. The ribosomal proteins (RPs), comprising the structural parts of the ribosome, are essential for ribosome assembly and function. In addition to their canonical ribosomal functions, multiple RPs have extra-ribosomal functions including activation of p53-dependent or p53-independent pathways in response to stress, resulting in cell cycle arrest and apoptosis. Defects in ribosome biogenesis, translation, and the functions of individual RPs, including mutations in RPs have been linked to a diverse range of human congenital disorders termed ribosomopathies. Ribosomopathies are characterized by tissue-specific phenotypic abnormalities and higher cancer risk later in life. Recent discoveries of somatic mutations in RPs in multiple tumor types reinforce the connections between ribosomal defects and cancer. In this article, we review the most recent advances in understanding the molecular consequences of RP mutations and ribosomal defects in ribosomopathies and cancer. We particularly discuss the molecular basis of the transition from hypo- to hyper-proliferation in ribosomopathies with elevated cancer risk, a paradox termed "Dameshek's riddle." Furthermore, we review the current treatments for ribosomopathies and prospective therapies targeting ribosomal defects. We also highlight recent advances in ribosome stress-based cancer therapeutics. Importantly, insights into the mechanisms of resistance to therapies targeting ribosome biogenesis bring new perspectives into the molecular basis of cancer susceptibility in ribosomopathies and new clinical implications for cancer therapy.

Bioinformatics Analysis and Identification of Genes and Molecular Pathways Involved in Venous Thromboembolism (VTE)

OBJECTIVES

To explore the key genes, and correlated pathways in venous thromboembolism (VTE) via bioinformatic analysis, and expected our findings could contribute to the development of new biomarkers and therapeutic target for VTE.

METHODS

Two VTE-related microarray expression profiles (GSE48000 and GSE19151) were downloaded from the Gene Expression Ominibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using limma package, and overlapping DEGs were identified form the above two expression profiles. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) pathway enrichment analyses were performed by DAVID. Protein-protein interaction (PPI) network was constructed by using STRING and visualized with Cytoscape. Furthermore, module analysis plus centrality analysis of the PPI network were executed to identify the potential key genes. Finally, the pathway analysis was performed using GenCLiP 3.0.

RESULTS

A total of 173 DEGs (125 upregulated and 48 downregulated) were identified. GO analysis demonstrated that DEGs were mainly enriched in viral life cycle, ribosome and structural constituent of ribosome. Meanwhile, KEGG pathway analysis showed that these genes were enriched in ribosome, Parkinson's disease and cell cycle. Additionally, one most significant module and 12 hub genes were found. Finally, 6 key genes, namely ISG15, RPS15A, MRPL13, ICT1, MRPL15 and RPLP0, with high centrality features were identified. These key genes were mainly involved in translation, metabolism of proteins and ribosome pathway.

CONCLUSIONS

In summary, these 6 identified genes and correlated pathways should play an important role in VTE, which can provide new insight into the molecular mechanism, potential biomarkers and therapeutic targets associated with VTE.

Cisplatin-Resistant Gastric Cancer Cells Promote the Chemoresistance of Cisplatin-Sensitive Cells via the Exosomal RPS3-Mediated PI3K-Akt-Cofilin-1 Signaling Axis

Cisplatin is an important agent in first-line chemotherapy against gastric cancer (GC). However, consequential drug resistance limits its effectiveness for the treatment of GC. In this study, a cisplatin resistant gastric cancer cell line SGC7901R was determined by LC-MS/MS with increased exosomal levels of RPS3 protein. SGC7901R cell-derived exosomes were readily taken up by cisplatin-sensitive SGC7901S cells, thus triggering off a phenotype of chemoresistance in the receptor cells. Subsequently, it was demonstrated that exosomal RPS3 was essential for inducing chemoresistance of receptor cells as shown by the acquisition of this phenotype in SGC7901S cells with enforced expression of RPS3. Further mechanism study demonstrated that cisplatin-resistant gastric cancer cell-derived exosomal RPS3 enhanced the chemoresistance of cisplatin-sensitive gastric cancer cells through the PI3K-Akt-cofilin-1 signaling pathway. All these findings demonstrated that cisplatin-resistant gastric cancer cells communicate with sensitive cells through the intercellular delivery of exosomal RPS3 and activation of the PI3K-Akt-cofilin-1 signaling pathway. Targeting exosomal RPS3 protein in cisplatin-resistant gastric cancer cells may thus be a promising strategy to overcome cisplatin resistance in gastric cancer.

Pioglitazone ameliorates neuronal damage after traumatic brain injury via the PPARγ/NF-κB/IL-6 signaling pathway

Traumatic brain injury (TBI) is the major cause of high mortality and disability rates worldwide. Pioglitazone is an activator of peroxisome proliferator-activated receptor-gamma (PPARγ) that can reduce inflammation following TBI. Clinically, neuroinflammation after TBI lacks effective treatment. Although there are many studies on PPARγ in TBI animals, only few could be converted into clinical, since TBI mechanisms in humans and animals are not completely consistent. The present study, provided a potential theoretical basis and therapeutic target for neuroinflammation treatment after TBI. First, we detected interleukin-6 (IL-6), nitric oxide (NO) and Caspase-3 in TBI clinical specimens, confirming a presence of a high expression of inflammatory factors. Western blot (WB), quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) were used to detect PPARγ, IL-6, and p-NF-κB to identify the mechanisms of neuroinflammation. Then, in the rat TBI model, neurobehavioral and cerebral edema levels were investigated after intervention with pioglitazone (PPARγ activator) or T0070907 (PPARγ inhibitor), and PPARγ, IL-6 and p-NF-κB were detected again by qRT-PCR, WB and immunofluorescence (IF). The obtained results revealed that: 1) increased expression of IL-6, NO and Caspase-3 in serum and cerebrospinal fluid in patients after TBI, and decreased PPARγ in brain tissue; 2) pioglitazone could improve neurobehavioral and reduce brain edema in rats after TBI; 3) the protective effect of pioglitazone was achieved by activating PPARγ and reducing NF-κB and IL-6. The neuroprotective effect of pioglitazone on TBI was mediated through the PPARγ/NF-κB/IL-6 pathway.

Curcumin-Loaded Solid Lipid Nanoparticles Bypass P-Glycoprotein Mediated Doxorubicin Resistance in Triple Negative Breast Cancer Cells

Multidrug resistance (MDR) is a critical hindrance to the success of cancer chemotherapy. The main thing responsible for MDR phenotypes are plasma-membranes associated with adenosine triphosphate (ATP) Binding Cassette (ABC) drug efflux transporters, such as the P-glycoprotein (Pgp) transporter that has the broadest spectrum of substrates. Curcumin (CURC) is a Pgp inhibitor, but it is poorly soluble and bioavailable. To overcome these limitations, we validated the efficacy and safety of CURC, loaded in biocompatible solid lipid nanoparticles (SLNs), with or without chitosan coating, with the goal of increasing the stability, homogeneous water dispersibility, and cellular uptake. Both CURC-loaded SLNs were 5–10-fold more effective than free CURC in increasing the intracellular retention and toxicity of doxorubicin in Pgp-expressing triple negative breast cancer (TNBC). The effect was due to the decrease of intracellular reactive oxygen species, consequent inhibition of the Akt/IKKα-β/NF-kB axis, and reduced transcriptional activation of the Pgp promoter by p65/p50 NF-kB. CURC-loaded SLNs also effectively rescued the sensitivity to doxorubicin against drug-resistant TNBC tumors, without signs of systemic toxicity. These results suggest that the combination therapy, based on CURC-loaded SLNs and doxorubicin, is an effective and safe approach to overcome the Pgp-mediated chemoresistance in TNBC.

CMIP promotes Herceptin resistance of HER2 positive gastric cancer cells

Gastric cancer remains one of the most malignant human cancers with poor prognosis. Herceptin is a well-received antibody drug for HER2 positive gastric cancer. Primary Herceptin resistance and acquired Herceptin resistance retarded the use of Herceptin for gastric cancer. We herein reported CMIP (C-Maf-inducing protein) was overexpressed in Herceptin-resistant gastric cancer cells MKN45-HR and NCI-N87-HR; CMIP promoted Herceptin resistance of HER2 positive gastric cancer cells. SOX2 was examined to be positively regulated by CMIP and also promoted Herceptin resistance of HER2 positive gastric cancer cells. SOX2 might mediate the Herceptin resistance promoting role of CMIP in gastric cancer cells. Elevated expression of CMIP was associated with poor clinicopathological features including tumor size, lymph node metastasis and clinical stage in HER2 positive gastric cancer patients. Inhibitors of CMIP could be used as potential adjuvant therapeutic drugs for HER2 positive gastric cancer.

MicroRNA-147b suppresses the proliferation and invasion of non-small-cell lung cancer cells through downregulation of Wnt/β-catenin signalling via targeting of RPS15A

Deregulation of microRNAs (miRNAs) leads to malignant growth and aggressive invasion during cancer occurrence and progression. miR-147b has emerged as one of the cancer-related miRNAs that are dysregulated in multiple cancers. Yet, the relevance of miR-147b in non-small-cell lung cancer (NSCLC) remains unclear. In the present study, we aimed to report the biological function and signalling pathways mediated by miR-147b in NSCLC. Our results demonstrate that miR-147b expression is significantly downregulated in NSCLC tissues and cell lines. Overexpression of miR-147b decreased the proliferative ability, colony-forming capability, and invasive potential of NSCLC cells. Notably, our study identified ribosomal protein S15A (RPS15A), an oncogene in NSCLC, as a target gene of miR-147b. Our results showed that miR-147b negatively modulates RPS15A expression in NSCLC cells. An inverse correlation between miR-147b and RPS15A was evidenced in NSCLC specimens. Moreover, miR-147b overexpression downregulated the activation of Wnt/β-catenin signalling via targeting of RPS15A. Overexpression of RPS15A partially reversed the miR-147b-mediated antitumour effect in NSCLC cells. Collectively, these findings reveal that miR-147b restricts the proliferation and invasion of NSCLC cells by inhibiting RPS15A-induced Wnt/β-catenin signalling and suggest that the miR-147b/RPS15A/Wnt/β-catenin axis is an important regulatory mechanism for malignant progression of NSCLC.

METTL3-mediated N6-methyladenosine modification is critical for epithelial-mesenchymal transition and metastasis of gastric cancer

BACKGROUND

As one of the most frequent chemical modifications in eukaryotic mRNAs, N6-methyladenosine (m6A) modification exerts important effects on mRNA stability, splicing, and translation. Recently, the regulatory role of m6A in tumorigenesis has been increasingly recognized. However, dysregulation of m6A and its functions in tumor epithelial-mesenchymal transition (EMT) and metastasis remain obscure.

METHODS

qRT-PCR and immunohistochemistry were used to evaluate the expression of methyltransferase-like 3 (METTL3) in gastric cancer (GC). The effects of METTL3 on GC metastasis were investigated through in vitro and in vivo assays. The mechanism of METTL3 action was explored through transcriptome-sequencing, m6A-sequencing, m6A methylated RNA immunoprecipitation quantitative reverse transcription polymerase chain reaction (MeRIP qRT-PCR), confocal immunofluorescent assay, luciferase reporter assay, co-immunoprecipitation, RNA immunoprecipitation and chromatin immunoprecipitation assay.

RESULTS

Here, we show that METTL3, a major RNA N6-adenosine methyltransferase, was upregulated in GC. Clinically, elevated METTL3 level was predictive of poor prognosis. Functionally, we found that METTL3 was required for the EMT process in vitro and for metastasis in vivo. Mechanistically, we unveiled the METTL3-mediated m6A modification profile in GC cells for the first time and identified zinc finger MYM-type containing 1 (ZMYM1) as a bona fide m6A target of METTL3. The m6A modification of ZMYM1 mRNA by METTL3 enhanced its stability relying on the "reader" protein HuR (also known as ELAVL1) dependent pathway. In addition, ZMYM1 bound to and mediated the repression of E-cadherin promoter by recruiting the CtBP/LSD1/CoREST complex, thus facilitating the EMT program and metastasis.

CONCLUSIONS

Collectively, our findings indicate the critical role of m6A modification in GC and uncover METTL3/ZMYM1/E-cadherin signaling as a potential therapeutic target in anti-metastatic strategy against GC.

LINC01303 functions as a competing endogenous RNA to regulate EZH2 expression by sponging miR-101-3p in gastric cancer

Long non‐coding RNA (lncRNA) is one of the important regulators of many malignancies. However, the biological function and clinical significance of a large number of lncRNAs in gastric cancer remain unclear. Therefore, we analysed the TCGA data to find that LINC01303 is significantly up‐regulated in gastric cancer tissues. However, the biological function of LINC01303 in GC remains unknown. In our study, we found that the expression of LINC01303 was significantly higher in GC tissues than in adjacent tissues by real‐time quantitative PCR. We can significantly inhibit the malignant proliferation, migration and invasion of GC cells by silencing LINC01303 expression. In addition, LINC01303 knockdown can also inhibit GC growth in vivo. After the bioinformatics analysis, we found that LINC01303 can be used as a miR‐101‐3p sponge to competitively adsorb miR‐101‐3p with EZH2. Therefore, our results indicate that LINC01303 promotes the expression of EZH2 by inhibiting miR‐101‐3p activity and promotes GC progression. In summary, in this study, we demonstrated for the first time that the LINC01303/miR‐101‐3p/EZH2 axis promotes GC progression.

Downregulation of RPS15A by miR-29a-3p attenuates cell proliferation in colorectal carcinoma

miR-29a-3p has been reported to function as a tumor suppressor in several cancers. However, the biological function role of miR-29a-3p in colorectal carcinoma (CRC) has not been well investigated. In this study, we found that miR-29a-3p was at lower level expression in CRC tissues and cell lines. Experimental up-regulation miR-29a-3p with mimic could inhibit cell proliferation, but induced cell cycle arrest at G0/G1 phase and apoptosis in CRC cells. MiR-29a-3p overexpression significantly down-regulated the expression levels of CDK4, Cyclin D1, and Bax, but up-regulated the expression levels of p21 and Bcl-2 in DLD-1 cells. Moreover, ribosomal protein S15A (RPS15A) was predicted and confirmed as a direct target gene of miR-29a-3p. Furthermore, restoration of RPS15A could rescue the phenotypic changes caused by miR-29a-3p. The findings demonstrate miR-29a-3p inhibits CRC cell function possibly by targeting RPS15A, which might be exploited therapeutically in CRC.

RPS15A promotes gastric cancer progression via activation of the Akt/IKK-β/NF-κB signalling pathway

This study aimed to investigate the clinical significance, potential biological function and underlying mechanism of RPS15A in gastric cancer (GC) progression. RPS15A expression was detected in 40 pairs of GC tissues and matched normal gastric mucosae (MNGM) using qRT‐PCR analysis. Immunohistochemistry assay was conducted using a tissue microarray including 186 primary GC samples to characterize the clinical significance of RPS15A. A series of in vitro and in vivo assays were performed to elucidate the biological function of RPS15A in GC development and underlying molecular mechanisms. The expression of RPS15A was significantly up‐regulated in GC samples compared to MNGM, and its expression was closely related to TNM stage, tumour size, differentiation, lymph node metastasis and poor patient survival. Ectopic expression of RPS15A markedly enhanced the proliferation and metastasis of GC cells both in vitro and in vivo. RPS15A overexpression also promoted the epithelial‐mesenchymal transition (EMT) phenotype formation of GC cells. Investigations of underlying mechanisms found that RPS15A activated the NF‐κB signalling pathway by inducing the nuclear translocation and phosphorylation of the p65 NF‐κB subunit, transactivation of NF‐κB reporter and up‐regulating target genes of this pathway. In addition, RPS15A overexpression activated, while RPS15A knockdown inhibited the Akt/IKK‐β signalling axis in GC cells. And both Akt inhibitor LY294002 and IKK inhibitor Bay117082 neutralized the p65 and p‐p65 nuclear translocation induced by RPS15A overexpression. Collectively, our findings suggest that RPS15A activates the NF‐κB pathway through Akt/IKK‐β signalling axis, and consequently promotes EMT and GC metastasis. This newly identified RPS15A/Akt/IKK‐β/NF‐κB signalling pathway may be a potential therapeutic target to prevent GC progression.