p53/MDM2 signaling pathway in aging, senescence and tumorigenesis.

A wealth of evidence has emerged that there is an association between aging, senescence and tumorigenesis. Senescence, a biological process by which cells cease to divide and enter a status of permanent cell cycle arrest, contributes to aging and aging-related diseases, including cancer. Aging populations have the higher incidence of cancer due to a lifetime of exposure to cancer-causing agents, reduction of repairing DNA damage, accumulated genetic mutations, and decreased immune system efficiency. Cancer patients undergoing cytotoxic therapies, such as chemotherapy and radiotherapy, accelerate aging. There is growing evidence that p53/MDM2 (murine double minute 2) axis is critically involved in regulation of aging, senescence and oncogenesis. Therefore, in this review, we describe the functions and mechanisms of p53/MDM2-mediated senescence, aging and carcinogenesis. Moreover, we highlight the small molecular inhibitors, natural compounds and PROTACs (proteolysis targeting chimeras) that target p53/MDM2 pathway to influence aging and cancer. Modification of p53/MDM2 could be a potential strategy for treatment of aging, senescence and tumorigenesis.

Prognostic heterogeneity of Ki67 in non-small cell lung cancer: A comprehensive reappraisal on immunohistochemistry and transcriptional data.

In the present study, the debatable prognostic value of Ki67 in patients with non-small cell lung cancer (NSCLC) was attributed to the heterogeneity between lung adenocarcinoma (LUAD) and lung squamous carcinoma (LUSC). Based on meta-analyses of 29 studies, a retrospective immunohistochemical cohort of 1479 patients from our center, eight transcriptional datasets and a single-cell datasets with 40 patients, we found that high Ki67 expression suggests a poor outcome in LUAD, but conversely, low Ki67 expression indicates worse prognosis in LUSC. Furthermore, low proliferation in LUSC is associated with higher metastatic capacity, which is related to the stronger epithelial-mesenchymal transition potential, immunosuppressive microenvironment and angiogenesis. Finally, nomogram model incorporating clinical risk factors and Ki67 expression outperformed the basic clinical model for the accurate prognostic prediction of LUSC. With the largest prognostic assessment of Ki67 from protein to mRNA level, our study highlights that Ki67 also has an important prognostic value in NSCLC, but separate evaluation of LUAD and LUSC is necessary to provide more valuable information for clinical decision-making in NSCLC.

Effects of Nurse-Led Interventions on Comprehensive Rehabilitation of Atrial Fibrillation: A Systematic Review And Meta-Analysis.

Objective: This meta-analysis aimed to assess and evaluate the effect of nurse-led health management on the quality of life of patients with atrial fibrillation. Methods: We compared the outcomes of patients who received nurse-led intervention during hospitalization with those who did not, using a systematic retrospective and randomized controlled trial (RCT) analysis. We searched the studies in Cochrane Central Register, including PubMed, EmBase, Web of Science, Cochrane Library, WAN Data, CBM, CNKI, etc. Bias risks included in the study were evaluated by Cochrane Bias risk tool , and combined risk estimates were calculated. The main endpoints are the SF-36 and HADS scores and endpoints after surgery. We used a random effects model to combine the data. For continuous variables (such as SF-36 and HADS scores), we used standard mean difference for analysis, and for binary variables (such as the presence or absence of mental health problems), we used hazard ratio for analysis. The data are based on fixed or stochastic effects models, with standard mean differences and risk ratios for continuous and heterotaxic variables. Results: 3064 patients from 7 clinical studies were included in this meta-analysis. Postoperative SF-36 scores at 6 months in the nurse-led group were significantly higher than those in the routine nursing group in Role-Physical and Mental health. Postoperative SF-36 scores at 12 months in the nurse-led group were not significantly higher than those in the routine nursing group. The nurse-led group had a significantly lower HADS depression score than the conventional care group, but there was no significant difference in HADS anxiety score between the two groups. Conclusion: The main findings of this meta-analysis are that the nurse-led comprehensive management of atrial fibrillation can significantly improve the role-physical and mental health status of SF-36, reduce the HADS depression score, the incidence of cardiovascular hospitalization and atrial fibrillation at 6 months atrial fibrillation surgery. Additional high-quality RCTs should be conducted in the future. nurse-led interventions have the potential to significantly impact the care of patients with atrial fibrillation. By providing comprehensive management, education, and support, nurses can improve patient outcomes, enhance quality of life, and reduce healthcare burdens for both patients and providers. While this meta-analysis provides valuable insights, there are limitations that should be considered. Standardizing interventions and outcome measures, conducting larger studies with longer follow-up periods, including diverse populations and settings, and assessing the economic impact of nurse-led interventions are potential directions for future research in this field. Addressing these limitations would provide a more comprehensive understanding of the role of nurse-led interventions in the care of patients with atrial fibrillation.

Retracted: Upregulation of Serine Proteinase Inhibitor Clade B Member 3 (SERPINB3) Expression by Stromal Cell-Derived Factor (SDF-1)/CXCR4/Nuclear Factor kappa B (NF-κB) Promotes Migration and Invasion of Gastric Cancer Cells.

The Editors of Medical Science Monitor wish to inform you that the above manuscript has been retracted from publication due to concerns with the credibility and originality of the study, the manuscript content, and the Figure images. Reference: Jing Gong, Yongxi Song, Ling Xu, Xiaofang Che, Kezuo Hou, Tianshu Guo, Yu Cheng, Yunpeng Liu, Xiujuan Qu. Upregulation of Serine Proteinase Inhibitor Clade B Member 3 (SERPINB3) Expression by Stromal Cell-Derived Factor (SDF-1)/CXCR4/Nuclear Factor kappa B (NF-kB) Promotes Migration and Invasion of Gastric Cancer Cells. Med Sci Monit, 2020; 26: e927411. DOI: 10.12659/MSM.927411.

Nitazoxanide induced myocardial injury in zebrafish embryos by activating oxidative stress response.

Nitazoxanide (NTZ) is a broad-spectrum antiparasitic and antiviral drug (thiazole). However, although NTZ has been extensively used, there are no reports concerning its toxicology in vertebrates. This study used the zebrafish as a vertebrate model to evaluate the safety of NTZ and to analyse the related molecular mechanisms. The experimental results showed that zebrafish embryos exposed to NTZ had cardiac malformation and dysfunction. NTZ also significantly inhibited proliferation and promoted apoptosis in cardiomyocytes. Transcriptomic analysis used compared gene expression levels between zebrafish embryos in the NTZ treatment and the control groups identified 200 upregulated genes and 232 downregulated genes. Analysis by Kyoto encyclopaedia of genes and genomes (KEGG) and gene ontology (GO) showed that signal pathways on cardiomyocyte development were inhibited while the oxidative stress pathways were activated. Further experiments showed that NTZ increased the content of reactive oxygen species (ROS) in the hearts of zebrafish. Antioxidant gadofullerene nanoparticles (GFNPs) significantly alleviated the developmental toxicity to the heart, indicating that NTZ activated the oxidative stress response to cause embryonic cardiomyocyte injury in zebrafish. This study provides evidence that NTZ causes developmental abnormalities in the cardiovascular system of zebrafish.

Knockdown of G-protein-signaling modulator 2 promotes metastasis of non-small-cell lung cancer by inducing the expression of Snail.

Non-small-cell lung cancer (NSCLC) is the leading global cause of cancer-related death. Due to the lack of reliable diagnostic or prognostic biomarkers, the prognosis of NSCLC remains poor. Consequently, there is an urgent need to explore the mechanisms underlying this condition in order to identify effective biomarkers. G-protein-signaling modulator 2 (GPSM2) is widely recognized as a determinant of mitotic spindle orientation. However, its role in cancer, especially NSCLC, remains uncertain. In this study, we found that GPSM2 was downregulated in NSCLC tissues and was correlated with a poor prognosis. Furthermore, the knockdown of GPSM2 promoted NSCLC cell metastasis in vitro and in vivo and accelerated the process of epithelial-mesenchymal transition (EMT). Mechanistically, we showed that silencing GPSM2 induced cell metastasis and EMT through the ERK/glycogen synthase kinase-3ß/Snail pathway. These results confirm that GPSM2 plays an important role in NSCLC. Moreover, GPSM2, as an independent prognostic factor, could be a potential prognostic biomarker and drug target for NSCLC.

Activation of IGF-1R pathway and NPM-ALK G1269A mutation confer resistance to crizotinib treatment in NPM-ALK positive lymphoma.

ALK-positive anaplastic large cell lymphoma (ALCL) represents a subset of non-Hodgkin's lymphoma that is treated with crizotinib, a dual ALK/MET inhibitor. Despite the remarkable initial response, ALCLs eventually develop resistance to crizotinib. ALK inhibitor resistance in tumors is a complex and heterogeneous process with multiple underlying mechanisms, including ALK gene amplification, ALK kinase domain mutation, and the activation of various bypass signaling pathways. To overcome resistance, multiple promising next-generation ALK kinase inhibitors and rational combinatorial strategies are being developed. To determine how cancers acquire resistance to ALK inhibitors, we established a model of acquired crizotinib resistance by exposing a highly sensitive NPM-ALK-positive ALCL cell line to increasing doses of crizotinib until resistance emerged. We found that the NPM-ALK mutation was selected under intermediate-concentration drug stress in resistant clones, accompanied by activation of the IGF-1R pathway. In the crizotinib-resistant ALCL cell model, the IGF-1R pathway was activated, and combined ALK/IGF-1R inhibition improved therapeutic efficacy. Furthermore, we also detected the NPM-ALK G1269A mutation, which had previously been demonstrated to result in decreased affinity for crizotinib, in the resistant cell model. Although crizotinib was ineffective against cells harboring the NPM-ALK G1269A mutation, five structurally different ALK inhibitors, alectinib, ceritinib, TAE684, ASP3026 and AP26113, maintained activity against the resistant cells. Thus, we have shown that second-generation ALK tyrosine kinase inhibitors or IGF-1R inhibitors are effective in treating crizotinib-resistant tumors.

FEN1 mediates miR-200a methylation and promotes breast cancer cell growth via MET and EGFR signaling.

Flap endonuclease 1 (FEN1) is recognized as a pivotal factor in DNA replication, long-patch excision repair, and telomere maintenance. Excessive FEN1 expression has been reported to be closely associated with cancer progression, but the specific mechanism has not yet been explored. In the present study, we demonstrated that FEN1 promoted breast cancer cell proliferation via an epigenetic mechanism of FEN1-mediated up-regulation of DNA methyltransferase (DNMT)1 and DNMT3a. FEN1 was proved to interact with DNMT3a through proliferating cell nuclear antigen (PCNA) to suppress microRNA (miR)-200a-5p expression mediated by methylation. Furthermore, miR-200a-5p was identified to repress breast cancer cell proliferation by inhibiting the expression of its target genes, hepatocyte growth factor (MET), and epidermal growth factor receptor (EGFR). Overall, our data surprisingly demonstrate that FEN1 promotes breast cancer cell growth via the formation of FEN1/PCNA/DNMT3a complex to inhibit miR-200a expression by DNMT-mediated methylation and to recover the target genes expression of miR-200a, MET, and EGFR. The novel epigenetic mechanism of FEN1 on proliferation promotion provides a significant clue that FEN1 might serve as a predictive biomarker and therapeutic target for breast cancer.-Zeng, X., Qu, X., Zhao, C., Xu, L., Hou, K., Liu, Y., Zhang, N., Feng, J., Shi, S., Zhang, L., Xiao, J., Guo, Z., Teng, Y., Che, X. FEN1 mediates miR-200a methylation and promotes breast cancer cell growth via MET and EGFR signaling.

Lymecycline reverses acquired EGFR-TKI resistance in non-small-cell lung cancer by targeting GRB2.

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) were first-line treatments for NSCLC patients with EGFR-mutations. However, about 30 % of responders relapsed within six months because of acquired resistance. In this study, we used Connectivity Map (CMap) to discover a drug capable of reversing acquired EGFR-TKIs resistance. To investigate Lymecycline's ability to reverse acquired EGFR-TKIs resistance, two Icotinib resistant cell lines were constructed. Lymecycline's ability to suppress the proliferation of Icotinib resistant cells in vitro and in vivo was then evaluated. Molecular targets were predicted using network pharmacology and used to identify the molecular mechanism. Growth factor receptor-bound protein 2 (GRB2) is an EGFR-binding adaptor protein essential for EGFR phosphorylation and regulation of AKT/ERK/STAT3 signaling pathways. Lymecycline targeted GRB2 and inhibited the resistance of the cell cycle to EGFR-TKI, arresting disease progression and inducing apoptosis in cancer cells. Combined Lymecycline and Icotinib treatment produced a synergistic effect and induced apoptosis in HCC827R5 and PC9R10 cells. Cell proliferation in resistant cancer cells was significantly inhibited by the combined Lymecycline and Icotinib treatment in mouse models. Lymecycline inhibited the resistance of the cell cycle to EGFR-TKI and induced apoptosis in NSCLC by inhibiting EGFR phosphorylation and GRB2-mediated AKT/ERK/STAT3 signaling pathways. This provided strong support that Lymecycline when combined with EGFR targeting drugs, enhanced the efficacy of treatments for drug-resistant NSCLC.

Positive Cross-Talk Between CXC Chemokine Receptor 4 (CXCR4) and Epidermal Growth Factor Receptor (EGFR) Promotes Gastric Cancer Metastasis via the Nuclear Factor kappa B (NF-kB)-Dependent Pathway.

BACKGROUND Previous studies have established cross-talk between CXC chemokine receptor 4 (CXCR4) and epidermal growth factor receptor (EGFR) in gastric cancer, however, the effect of dual CXCR4/EGFR tumor status on patient survival and mechanisms regulating expression has yet to be investigated. MATERIAL AND METHODS A total of 56 gastric cancer patients were recruited to reveal the relationship between CXCR4 and EGFR expression, and the clinic-pathological features of samples were investigated by immunohistochemical staining. Two gastric cancer cell lines were treated with CXCL12 or EGF, and expression levels of CXCR4 and EGFR were detected by reverse-transcription-polymerase chain reaction and western blotting. Cells were treated with an NF-kappaB pathway inhibitor to investigate its role in the regulation of CXCL12 or EGF-mediated CXCR4 and EGFR expression and migration ability. RESULTS The results show that CXCL12 upregulated CXCR4 and EGFR. Similarly, EGF could induce the expression of CXCR4 and contribute to gastric cancer cell metastasis. In addition, both CXCL12 and EGF could induce the activation of IKKalphaß and P65. Conversely, suppression of the NF-kappaB pathway remarkably decreased the expression of CXCR4/EGFR and migration ability induced by EGF or CXCL12. Furthermore, a significantly positive correlation between CXCR4 and EGFR expression was observed in gastric cancer patient tissues (r=0.372, P=0.005). Samples expressing both receptors had significantly poorer patient prognosis than other patient groups (P=0.002). CONCLUSIONS Our results showed that the CXCL12/CXCR4 and EGF/EGFR axis can regulate the expression of each other through the NF-kappaB pathway to promote metastasis. These data suggested that simultaneous inhibition of EGFR and CXCR4 may be a potential therapeutic strategy in gastric cancer.

Upregulation of Serine Proteinase Inhibitor Clade B Member 3 (SERPINB3) Expression by Stromal Cell-Derived Factor (SDF-1)/CXCR4/Nuclear Factor kappa B (NF-κB) Promotes Migration and Invasion of Gastric Cancer Cells.

BACKGROUND Serine proteinase inhibitor clade B member 3 (SERPINB3) is a neutral glycoprotein. Its overexpression is related to the promotion of cell proliferation and activation via the nuclear factor kappa B (NF-kappaB) pathway in several tumors. Whether it can participate in stromal cell-derived factor (SDF-1)/NF-kappaB-induced metastasis of gastric cancer has not been reported. MATERIAL AND METHODS We analyzed the ability of SDF-1 to induce migration and invasion in vitro by knocking down the expression of SERPINB3 with siRNAs in gastric cancer cells. We also explored the effects of a CXCR4 antagonist and NF-kappaB inhibitor on SERPINB3 expression. We verified the effect of SERPINB3 on prognosis in gastric cancer specimens by immunohistochemistry. RESULTS In vitro experiments confirmed that SDF-1 upregulated the expression of SERPINB3 and promoted metastasis in gastric cancer cells. This phenomenon was reversed by knockdown of SERPINB3, a chemokine receptor 4 (CXCR4) antagonist, and an NF-kappaB inhibitor, which downregulated the expression of SERPINB3. In patients with gastric cancer, a significant positive correlation was observed between CXCR4 and SERPINB3 expression (r=0.222, P=0.029). Moreover, double positivity for SERPINB3 and CXCR4 was certified to be an independent prognostic factor (HR=3.332, P<0.001). CXCR4-positive patients who also expressed SERPINB3 were inclined to suffer from lymph node metastasis, confirming that SERPINB3 is a downstream molecule of CXCR4. CONCLUSIONS In vitro and pathological results showed that SDF-1/CXCR4 activated the NF-kappaB pathway and upregulated SERPINB3 to facilitate the migration and invasion of gastric cancer cells.

Signal transducer and activator of transcription 3 inhibition enhances vemurafenib sensitivity in colon cancers harboring the BRAFV600E mutation.

The BRAFV600E inhibitor vemurafenib is widely used to treat melanomas harboring the activated BRAFV600E mutation; however, vemurafenib showed poor efficacy in colon cancer, which impeded its clinical application for colon cancer patients with this mutation. The specific mechanism of vemurafenib resistance is not clear in colon cancer. In this study, we demonstrated that signal transducer and activator of transcription 3 (STAT3) activation influenced vemurafenib sensitivity in BRAFV600E mutant colon cancer cells. When vemurafenib was applied to two colon cancer cell lines with the BRAFV600E mutation, STAT3 was continuously activated after 6 hours. Furthermore, BCL-2 was upregulated in RKO colon cancer cells, while STAT3 remained unchanged in HT-29 colon cancer cells. This suggested that STAT3 signaling might be involved in vemurafenib sensitivity. Combining the STAT3 inhibitor STATTIC with vemurafenib further inhibited cell proliferation and promoted apoptosis by downregulating STAT3 and BCL-2 expression in RKO cells. Further studies showed that interleukin 6 (IL-6) secretion increased after RKO cells were treated with vemurafenib. STAT3 activation was induced by adding IL-6 to the supernatant, and IL-6 increased STAT3 and BCL-2 expression and antagonized vemurafenib sensitivity in HT-29 cells. Together, these results suggest that STAT3 activation maybe related to vemurafenib sensitivity in colon cancer cells, and that combining STAT3 inhibitors with vemurafenib may be a promising treatment for BRAFV600E mutant colon cancers.

Leucine-rich repeat neuronal protein-1 suppresses apoptosis of gastric cancer cells through regulation of Fas/FasL.

Gastric cancer (GC) is a common cause of cancer-related death worldwide. As a result of the lack of reliable diagnostic or prognostic biomarkers for GC, patient prognosis is still poor. Therefore, there is an urgent need for studies examining the underlying pathogenesis of GC in order to find effective biomarkers. LRRN1 (leucine-rich repeat neuronal protein-1) is a type I transmembrane protein that plays an important role in the process of nerve development and regeneration. However, its role in cancer, especially in GC, remains unclear. In the present study, we found that LRRN1 expression is upregulated in GC tissues and that high LRRN1 expression is associated with poor prognosis. siRNA and shRNA-mediated knockdowns of LRRN1 expression promoted GC cell apoptosis and activation of the Fas/FasL pathway. LRRN1 knockdown also resulted in upregulation of JUN, a subunit of the transcription factor AP-1 (activator protein-1). This suggests that LRRN1 suppresses GC cell apoptosis by downregulating AP-1, resulting in inhibition of the Fas/FasL pathway. These results confirm that LRRN1 plays a significant role in GC pathogenesis. Moreover, LRRN1 may be a potential prognostic biomarker and therapeutic target for GC.

Exosomal PD-L1 Retains Immunosuppressive Activity and is Associated with Gastric Cancer Prognosis.

BACKGROUND: A recent study showed that circulating exosomal PD-L1 is an effective predictor for anti-PD-1 therapy in melanomas. Exosomal PD-L1 induced immunosuppression microenvironments in cancer patients. However, its prognostic value and immunosuppressive effect in gastric cancer (GC) were poorly understood. METHODS: We retrospectively evaluated the prognostic value of exosomal PD-L1 and soluble PD-L1 in preoperative plasma of 69 GC patients. The correlation between exosomal PD-L1 and the T cell counts or cytokine in the plasma was evaluated in 31 metastatic GC patients before chemotherapy. RESULTS: Overall survival (OS) was significantly lower in the high exosomal PD-L1 group compared with the low exosomal PD-L1 group (P = 0.004). Exosomal PD-L1 was an independent prognostic factor in GC (n = 69, 95% confidence interval = 1.142-7.669, P = 0.026). However, soluble PD-L1 showed no correlation with OS (P = 0.139). Additionally, exosomal PD-L1 in the plasma samples of 31 metastatic GC patients was negatively associated with CD4+ T cell count (P = 0.001, R = - 0.549), CD8+ T-cell count (P = 0.054, R = - 0.349), and granzyme B (P = 0.002, R = - 0.537), indicating that exosomal PD-L1 was associated with immunosuppressive status of GC patients. GC cells also secreted exosomal PD-L1 and were positively associated with the amount of PD-L1 in corresponding GC cell lines. Besides, exosomal PD-L1 significantly decreased T-cell surface CD69 and PD-1 expressions compared with soluble PD-L1 due to its stable and MHC-I expression. CONCLUSIONS: Overall, exosomal PD-L1 predicts the worse survival and reflects the immune status in GC patients, resulting from a stronger T-cell dysfunction due to its stable and MHC-I expression.

Bufalin induces protective autophagy by Cbl-b regulating mTOR and ERK signaling pathways in gastric cancer cells.

Bufalin, a natural small-molecule compound derived from the traditional Chinese medicine Chan su, has shown promising anti-cancer effects against a broad variety of cancer cells through different mechanisms. It has been reported to induce autophagy in gastric cancer cells. However, the molecular mechanism involved is not fully elucidated. In the present study, we aimed to investigate the molecular mechanism by which bufalin induce autophagy in human gastric cancer cells. We found that bufalin induced apoptosis and autophagy in gastric cancer cells, and autophagy prevented human gastric cancer cells from undergoing apoptosis. Bufalin treatment changed the expression of autophagy-related proteins. Moreover, phosphorylated Akt, mTOR, and p70S6K were all significantly decreased, while phosphorylated ERK1/2 was increased by bufalin. Pretreatment of MGC803 cells with the ERK1/2-specific inhibitor PD98059 led to the down-regulation of LC3 II. Further study showed that Cbl-b positively regulated autophagy by suppressing mTOR and enhancing ERK1/2 activation. Therefore, our data provide evidence that bufalin induces autophagy in MGC803 cells via both Akt/mTOR/p70S6K and ERK signaling pathways, and Cbl-b-mediated suppression of mTOR and activation of ERK1/2 might play an important role.

Suppressed expression of Cbl-b by NF-κB mediates icotinib resistance in EGFR-mutant non-small-cell lung cancer.

Although epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) could greatly improve the prognosis of NSCLC patients harboring activating EGFR mutations, drug resistance still remains a major obstacle to successful treatment. Our previous study found that the EGFR-TKI icotinib could upregulate the expression of Casitas-B-lineage lymphoma protein-B (Cbl-b), an E3 ubiquitin ligase. In the present study, we aimed to clarify the potential role of Cbl-b in the resistance to icotinib, and the underlying mechanisms using EGFR-mutant cell lines. We found that icotinib inhibited the proliferation of mutant-EGFR NSCLC cells (PC9 and HCC827), and upregulated the expression of Cbl-b at both the protein and mRNA levels. Cbl-b knockdown decreased the sensitivity of PC9 and HCC827 cells to icotinib, and partially restored icotinib-inhibited AKT activation in PC9 cells. On the contrary, Cbl-b overexpression could partly reverse the drug resistance in PC9 icotinib-resistant cells (PC9/IcoR). Moreover, overexpressing p65, the main member of transcription factor NF-κB family, reversed the icotinib-mediated upregulation of Cbl-b. Collectively, these data suggest that icotinib could upregulate Cbl-b mediated by NF-κB inhibition, and Cbl-b contribute to the icotinib sensitivity in EGFR-mutant NSCLC cells. This study highlights that low expression of Cbl-b might be the key obstacles in the efficacy of icotinib therapy.

MiR-940 promotes the proliferation and migration of gastric cancer cells through up-regulation of programmed death ligand-1 expression.

Although anti-programmed death ligand-1 (PD-L1) therapy has shown light in treatment of gastric cancer, only a limited number of patients respond to the treatment. In addition to its immunosuppressive effect, PD-L1 is involved in other functions of tumor cells. Previously study showed that PD-L1 promoted EMT in lung cancer cells. However, the other effect and role of PD-L1 in gastric cancer remains unclear. In the present study, we first demonstrated that PD-L1 promoted the proliferation and migration in gastric cancer cell lines. We found that another STAT family member, STAT5a, is involved in regulating the expression of PD-L1 in gastric cancer. Additionally, Cbl-b interacted and ubiquitated STAT5a, down-regulated the expression of STAT5a and PD-L1. Moreover, bioinformatics predictions and experimental data showed that Cbl-b is a target gene of the microRNA miR-940. We further found that miR-940 promoted the proliferation and migration of gastric cancer in vivo and in vitro. Taken together, our findings suggest that miR-940/Cbl-b/STAT5a axis regulated the expression of PD-L1, which promotes the proliferation and migration of gastric cancer cells.

Cancer-associated fibroblasts-stimulated interleukin-11 promotes metastasis of gastric cancer cells mediated by upregulation of MUC1.

Cancer-associated fibroblasts (CAFs) are major components of the tumor stroma and regulators of tumor progression. However, the molecular mechanism by which CAFs promote gastric cancer progression should be further explored. In our study, we found that interleukin-11 (IL-11) secretion was significantly increased when CAFs were co-cultured with gastric cancer cells. Co-culture system-derived IL-11 promoted the migration and invasion of gastric cancer cells, whereas the increase of migration and invasion was attenuated by a neutralizing antibody of IL-11 or inhibition of JAK/STAT3 and MAPK/ERK pathways with specific inhibitors. Taken together, these results revealed that CAFs play a significant role in the gastric cancer progression in the tumor microenvironment through IL-11-STAT3/ERK signaling by upregulating MUC1. Also, IL-11 targeted therapy can achieve an effective treatment against gastric cancer indirectly by exerting their action on stromal fibroblasts.

Long non-coding RNA UCA1 upregulation promotes the migration of hypoxia-resistant gastric cancer cells through the miR-7-5p/EGFR axis.

A variety of solid tumors are surrounded by a hypoxic microenvironment, which is known to be associated with high metastatic capability and resistance to various clinical therapies, contributing to a poor survival rate for cancer patients. Although the majority of previous studies on tumor-associated hypoxia have focused on acute hypoxia, chronic hypoxia more closely mimics the actual hypoxic microenvironment of a tumor. In this study, two novel hypoxia-resistant gastric cancer (HRGC) cell lines which could grow normally in 2% oxygen were established. The long non-coding RNA UCA1 was upregulated in HRGC cells, which promoted their migration. Bioinformatics analysis and a luciferase reporter assay showed that miR-7-5p could bind to specific sites of UCA1 to regulate the target EGFR through competitive endogenous RNA function. UCA1 directly interacted with miR-7-5p and decreased the binding of miR-7-5p to the EGFR 3'-untranslated region, which suppressed the degradation of EGFR mRNA by miR-7-5p. Therefore, long-term hypoxia induced UCA1 to promote cell migration by enhancing the expression of EGFR. This study thus reveals a new mechanism by which a hypoxic microenvironment promotes tumor metastasis, and highlights UCA1 as a potential biomarker for predicting the metastasis of gastric cancer to guide clinical treatment.

ß-Elemene inhibits peritoneal metastasis of gastric cancer cells by modulating FAK/Claudin-1 signaling.

Peritoneal metastasis is common in advanced gastric cancer patients and is typically associated with a worse prognosis. ß-Elemene is a natural compound that can be isolated from the Curcuma wenyujin plant and has been widely used in China to treat a variety of cancers. However, the anti-metastatic impacts of ß-elemene on gastric cancer remain unknown. In our study, we found that ß-elemene significantly inhibited the migration and invasive capacity of gastric cells in vitro and inhibited the capacity of gastric cancer cells to peritoneally diffuse and metastasize in vivo. Mechanistically, we demonstrated that the anti-metastatic effects of ß-elemene were exerted by downregulating the expression of Claudin-1. Furthermore, ß-elemene was found to inhibit the metastatic capacity of cells by downregulating FAK phosphorylation, which regulated Claudin-1. Overall, our result revealed that ß-elemene inhibited peritoneal metastases from gastric cancer by modulating the FAK/Claudin-1 pathway.