Activation of IGF1R by DARPP-32 promotes STAT3 signaling in gastric cancer cells

Elucidation of the anti-gastric cancer mechanism of Guiqi Baizhu Formula by integrative approach of chemical bioinformatics

Gastric cancer (GC) has posed a great threat to the lives of people around the world. To date, safer and more cost-effective therapy for GC is lacking. Traditional Chinese medicine (TCM) may provide some new options for this. Guiqi Baizhu Formula (GQBZF), a classic TCM formula, has been extensively used to treat GC, while its bioactive components and therapeutic mechanisms remain unclear. In this study, we evaluated the underlying mechanisms of GQBZF in treating GC by integrative approach of chemical bioinformatics. GQBZF lyophilized powder (0.0625 mg/mL, 0.125 mg/mL) significantly attenuated the expression of p-IGF1R, PI3K, p-PDK1, p-VEGFR2 to inhibit the proliferation, migration and induce apoptosis of gastric cancer cells, which was consistent with the network pharmacology. Additionally, atractylenolide Ⅰ, quercetin, glycyrol, physcione and aloe-emodin, emodin, kaempferol, licoflavone A were found to be the key compounds of GQBZF regulating IGF1R and VEGFR2, respectively. And among which, glycyrol and emodin were determined as key active compounds against GC by farther vitro experiments and LC/MS. Meanwhile, we also found that glycyrol inhibited MKN-45 cells proliferation and enhanced apoptosis, which might be related to the inhibition of IGF1R/PI3K/PDK1, and emodin could significantly attenuate the MKN-45 cells migration, which might be related to the inhibition of VEGFR2-related signaling pathway. These results were verified again by molecular dynamics simulation and binding interaction pattern. In summary, this study suggested that GQBZF and its key active components (glycyrol and emodin) can suppress IGF1R/PI3K/PDK1 and VEGFR2-related signaling pathway, thereby inhibiting tumor cell proliferation and migration and inducing apoptosis. These findings provided an important strategy for developing new agents and facilitated clinical use of GQBZF against GC.

Circumventing drug resistance in gastric cancer: A spatial multi-omics exploration of chemo and immuno-therapeutic response dynamics

BACKGROUND

Gastric Cancer (GC) characteristically exhibits heterogeneous responses to treatment, particularly in relation to immuno plus chemo therapy, necessitating a precision medicine approach. This study is centered around delineating the cellular and molecular underpinnings of drug resistance in this context.

METHODS

We undertook a comprehensive multi-omics exploration of postoperative tissues from GC patients undergoing the chemo and immuno-treatment regimen. Concurrently, an image deep learning model was developed to predict treatment responsiveness.

RESULTS

Our initial findings associate apical membrane cells with resistance to fluorouracil and oxaliplatin, critical constituents of the therapy. Further investigation into this cell population shed light on substantial interactions with resident macrophages, underscoring the role of intercellular communication in shaping treatment resistance. Subsequent ligand-receptor analysis unveiled specific molecular dialogues, most notably TGFB1-HSPB1 and LTF-S100A14, offering insights into potential signaling pathways implicated in resistance. Our SVM model, incorporating these multi-omics and spatial data, demonstrated significant predictive power, with AUC values of 0.93 and 0.84 in the exploration and validation cohorts respectively. Hence, our results underscore the utility of multi-omics and spatial data in modeling treatment response.

CONCLUSION

Our integrative approach, amalgamating mIHC assays, feature extraction, and machine learning, successfully unraveled the complex cellular interplay underlying drug resistance. This robust predictive model may serve as a valuable tool for personalizing therapeutic strategies and enhancing treatment outcomes in gastric cancer.

LncRNA JHDM1D-AS1 promotes osteogenic differentiation of periodontal ligament cells by targeting miR-532-5p to activate IGF1R signaling

OBJECTIVE

The aim of this study was to explore the mechanism underlying periodontal ligament cells (PDLCs) osteogenic differentiation.

BACKGROUND

Periodontitis causes damage to tooth-supporting apparatus and eventually leads to tooth loss. PDLCs hold great promise in periodontal regeneration due to their osteogenic features.

METHODS

The expression of osteogenic markers, lncRNA JHDM1D-AS1, miR-532-5p and IGF1R was examined. For osteogenic differentiation, primary human PDLCs (hPDLCs) were cultured in an osteogenic medium, and it was assessed by ALP activity and Alizarin Red staining. The interaction between JHDM1D-AS1, miR-532-5p and IGF1R was analyzed via dual luciferase, RIP and RNA pull-down assays.

RESULTS

JHDM1D-AS1 was up-regulated during osteogenic differentiation and its silencing inhibited hPDLC osteogenic differentiation. JHDM1D-AS1 worked as a miR-532-5p sponge in hPDLCs. miR-532-5p directly targeted IGF1R to suppress its expression, and miR-532-5p knockdown facilitated osteogenic differentiation of hPDLCs. Overexpression of IGF1R promoted osteogenic differentiation of hPDLCs via activating Notch/HES1 signaling in hPDLCs.

CONCLUSION

JHDM1D-AS1 promotes osteogenic differentiation of hPDLCs via sponging miR-532-5p to facilitate IGF1R expression and activate Notch/HES1 signaling.

cAMP-PKA/EPAC signaling and cancer: the interplay in tumor microenvironment

Cancer is a complex disease resulting from abnormal cell growth that is induced by a number of genetic and environmental factors. The tumor microenvironment (TME), which involves extracellular matrix, cancer-associated fibroblasts (CAF), tumor-infiltrating immune cells and angiogenesis, plays a critical role in tumor progression. Cyclic adenosine monophosphate (cAMP) is a second messenger that has pleiotropic effects on the TME. The downstream effectors of cAMP include cAMP-dependent protein kinase (PKA), exchange protein activated by cAMP (EPAC) and ion channels. While cAMP can activate PKA or EPAC and promote cancer cell growth, it can also inhibit cell proliferation and survival in context- and cancer type-dependent manner. Tumor-associated stromal cells, such as CAF and immune cells, can release cytokines and growth factors that either stimulate or inhibit cAMP production within the TME. Recent studies have shown that targeting cAMP signaling in the TME has therapeutic benefits in cancer. Small-molecule agents that inhibit adenylate cyclase and PKA have been shown to inhibit tumor growth. In addition, cAMP-elevating agents, such as forskolin, can not only induce cancer cell death, but also directly inhibit cell proliferation in some cancer types. In this review, we summarize current understanding of cAMP signaling in cancer biology and immunology and discuss the basis for its context-dependent dual role in oncogenesis. Understanding the precise mechanisms by which cAMP and the TME interact in cancer will be critical for the development of effective therapies. Future studies aimed at investigating the cAMP-cancer axis and its regulation in the TME may provide new insights into the underlying mechanisms of tumorigenesis and lead to the development of novel therapeutic strategies.

α5-nAChR/STAT3/CD47 axis contributed to nicotine-related lung adenocarcinoma progression and immune escape

OBJECTIVES

The CHRNΑ5 gene, which encodes the α5-nicotinic acetylcholine receptor (α5-nAChR), is related to lung cancer and nicotine addiction. Smoking is closely related to the immunosuppressive effect of macrophages. CD47, a phagocytosis checkpoint in macrophages, is a therapeutic target in various cancer types. Nevertheless, the relationship between α5-nAChR and CD47 in lung cancer is still unclear.

METHODS AND RESULTS

The present study showed that α5-nAChR-mediated CD47 expression via STAT3 signaling, consequently leading to tumor progression and immune suppression in lung adenocarcinoma (LUAD). α5-nAChR expression was correlated with STAT3 expression, CD47 expression, smoking status and poor prognosis of LUAD in vivo. In vitro, α5-nAChR expression mediated the phosphorylation of STAT3, and phosphorylated STAT3 bound to the CD47 promoter and mediated CD47 expression. Downregulation of α5-nAChR and/or CD47 significantly reduced cell proliferation, migration, invasion, stemness and IL-10 expression, but increased TNF-α expression and phagocytosis of macrophages in LUAD. Furthermore, α5-nAChR/CD47 signaling contributed to the growth of subcutaneous xenograft tumors and liver metastasis of tumors in mice.

CONCLUSION

The α5-nAChR/STAT3/CD47 axis contributed to the progression and immune escape of lung cancer and may be a potential target for LUAD immunotherapy.

P2RY13 is a prognostic biomarker and associated with immune infiltrates in renal clear cell carcinoma: A comprehensive bioinformatic study

Background and Aims

Clear cell renal cell carcinoma (ccRCC) is a common and aggressive form of cancer with a high incidence globally. This study aimed to investigate the role of P2RY13 in the progression of ccRCC and elucidate its mechanism of action.

Methods

Gene Expression Omnibus and The Cancer Genome Atlas databases were used to extract gene expression profiles of ccRCC. These profiles were annotated and visualized by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses, as well as Gene Set Enrichment Analysis (GSEA). The STRING database was used to establish a protein-protein interaction network and to analyze the functional similarity. The GEPIA2 database was used to predict survival associated with hub genes. Meanwhile, the TIMER2.0 database was used to assess immune cell infiltration and its link with the hub genes. Immunohistochemistry (IHC) was used to determine the difference between ccRCC and adjacent normal tissue.

Results

We identified 272 differentially expressed genes (DEGs). GO and KEGG analyses suggested that DEGs were primarily involved in lymphocyte activation, inflammatory response, immunological effector mechanism pathways. By cytohubba, the 20 highest-scoring hub genes were screened to identify critical genes in the protein-protein interaction network linked with ccRCC. Resting dendritic cells, CD8 T cells, and activated mast cells all showed a significant positive correlation with these hub genes. Moreover, a higher immune score was associated with increased prognostic risk scores, which in turn correlated with a poorer prognosis. IHC revealed that P2RY13 was expressed at higher levels in ccRCC compared to para-cancer tissues.

Conclusion

Identifying the DEGs will aid in the understanding of the causes and molecular mechanisms involved in ccRCC. P2RY13 may play a pivotal role in the progression and prognosis of ccRCC, potentially driving carcinogenesis though immune system mechanisms.

Dopamine and cyclic adenosine monophosphate-regulated phosphoprotein with an apparent Mr of 32000 promotes colorectal cancer growth

BACKGROUND

Dopamine and cyclic adenosine monophosphate (cAMP)-regulated phosphoprotein with an apparent Mr of 32000 (DARPP-32) is a protein that is involved in regulating dopamine and cAMP signaling pathways in the brain. However, recent studies have shown that DARPP-32 is also expressed in other tissues, including colorectal cancer (CRC), where its function is not well understood.

AIM

To explore the effect of DARPP-32 on CRC progression.

METHODS

The expression levels of DARPP-32 were assessed in CRC tissues using both quantitative polymerase chain reaction and immunohistochemistry assays. The proliferative capacity of CRC cell lines was evaluated with Cell Counting Kit-8 and 5-ethynyl-2’-deoxyuridine assays, while apoptosis was measured by flow cytometry. The migratory and invasive potential of CRC cell lines were determined using wound healing and transwell chamber assays. In vivo studies involved monitoring the growth rate of xenograft tumors. Finally, the underlying molecular mechanism of DARPP-32 was investigated through RNA-sequencing and western blot analyses.

RESULTS

DARPP-32 was frequently upregulated in CRC and associated with abnormal clinicopathological features in CRC. Overexpression of DARPP-32 was shown to promote cancer cell proliferation, migration, and invasion and reduce apoptosis. DARPP-32 knockdown resulted in the opposite functional effects. Mechanistically, DARPP-32 may regulate the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway in order to carry out its biological function.

CONCLUSION

DARPP-32 promotes CRC progression via the PI3K/AKT signaling pathway.

Dopamine receptors gene overexpression in the microenvironment of invasive gastric cancer and its potential implications

BACKGROUND

Gastric cancer (GC) is the fifth most common cancer worldwide and the most commonly diagnosed cancer in Iran. The nervous system provides proximity to tumor cells by releasing neurotransmitters such as dopamine and presenting them to the corresponding receptor-bearing tumors. While nerve fibers infiltrate the tumor microenvironment, little is known about the expression levels of dopamine (DA), dopamine receptors (DRs), and catechol-O-methyltransferase (COMT) in GC patients.

METHODS

DRs and COMT expression were analyzed in 45 peripheral blood mononuclear cells (PBMCs) and 20 paired tumor and adjacent tissue of GC patients by quantitative polymerase chain reaction. DA was measured in plasma specimens using enzyme-linked immunosorbent assay. Protein-protein interaction analysis was carried out to identify GC-related hub genes.

RESULTS

Increased expression of DRD1-DRD3 was found in tumor specimens compared with adjacent non-cancerous specimens (P < 0.05). A positive correlation was found between DRD1 and DRD3 expression (P = 0.009); DRD2 and DRD3 expression (P = 0.04). Plasma levels of dopamine were significantly lower in patients (1298 pg/ml) than in controls (4651 pg/ml). DRD1-DRD4 and COMT were up-regulated in PBMCs of patients compared with controls (P < 0.0001). Bioinformatic analyses showed 30 hub genes associated with Protein kinase A and extracellular signal-regulated kinase signaling pathways.

CONCLUSIONS

The findings indicated dysregulation of DRs and COMT mRNA expression in GC and suggest that the brain- gastrointestinal axis may mediate gastric cancer development. Network analysis revealed that combination treatments could be considered for optimizing and improving the precision treatment of GC.

Combining of immunotherapeutic approaches with chemotherapy for treatment of gastric cancer: Achievements and limitations

Evidence reveals that gastric cancer (GC) is the fifth most common malignancy in humans, and about 770,000 people die from this cancer yearly. It has been reported that new cases and deaths from GC are more common in men than women. Therapeutic approaches, such as surgery, chemotherapy, and radiotherapy, have been common for treating GC. Nevertheless, due to the complications and limitations of these methods, researchers use novel approaches, such as immunotherapeutic or target therapies, to evaluate the effectiveness of treatment in patients with metastatic GC. Studies have shown that monotherapy is usually associated with unpromising outcomes, and combination therapy can be a more practical option for treating metastatic GC. Therefore, to clarify different aspects of chemotherapy and immunotherapy in patients with metastatic GC, this review discussed the achievements and challenges of combining immunotherapeutic methods with chemotherapeutic agents.

CDK1 bridges NF-κB and β-catenin signaling in response to H. pylori infection in gastric tumorigenesis

Infection with Helicobacter pylori (H. pylori) is the main risk factor for gastric cancer, a leading cause of cancer-related death worldwide. The oncogenic functions of cyclin-dependent kinase 1 (CDK1) are not fully understood in gastric tumorigenesis. Using public datasets, quantitative real-time PCR, western blot, and immunohistochemical (IHC) analyses, we detect high levels of CDK1 in human and mouse gastric tumors. H. pylori infection induces activation of nuclear factor κB (NF-κB) with a significant increase in CDK1 in in vitro and in vivo models (p < 0.01). We confirm active NF-κB binding sites on the CDK1 promoter sequence. CDK1 phosphorylates and inhibits GSK-3β activity through direct binding with subsequent accumulation and activation of β-catenin. CDK1 silencing or pharmacologic inhibition reverses these effects and impairs tumor organoids and spheroid formation. IHC analysis demonstrates a positive correlation between CDK1 and β-catenin. The results demonstrate a mechanistic link between infection, inflammation, and gastric tumorigenesis where CDK1 plays a critical role.

Gastric organoids: Advancing the study of H. pylori pathogenesis and inflammation

For decades, traditional in vitro and in vivo models used for the study of Helicobacter pylori infection have relied heavily on the use of gastric cancer cell lines and rodents. Major challenges faced by these methods have been the inability to study cancer initiation in already cancerous cell lines, and the difficulty in translating results obtained in animal models due to genetic differences. These challenges have prevented a thorough understanding of the pathogenesis of disease and slowed the development of cancer therapies and a suitable vaccine against the pathogen. In recent years, the development of gastric organoids has provided great advantages over the traditional in vivo and in vitro models due to their similarities to the human stomach in vivo, their ease of use, and the capacity for long-term culture. This review discusses the advantages and limitations of existing in vivo and in vitro models of H. pylori infection, and how gastric organoids have been applied to study H. pylori pathogenesis, with a focus on how the pathogen interacts with the gastric epithelium, inflammatory processes, epithelial repair, and cancer initiation. The potential applications of organoids to address more complex questions on the role of hormones, vaccine-induced immunity are also discussed.

JAK/STAT Signaling: Molecular Targets, Therapeutic Opportunities, and Limitations of Targeted Inhibitions in Solid Malignancies

JAK/STAT signaling pathway is one of the important regulatory signaling cascades for the myriad of cellular processes initiated by various types of ligands such as growth factors, hormones, and cytokines. The physiological processes regulated by JAK/STAT signaling are immune regulation, cell proliferation, cell survival, apoptosis and hematopoiesis of myeloid and non-myeloid cells. Dysregulation of JAK/STAT signaling is reported in various immunological disorders, hematological and other solid malignancies through various oncogenic activation mutations in receptors, downstream mediators, and associated transcriptional factors such as STATs. STATs typically have a dual role when explored in the context of cancer. While several members of the STAT family are involved in malignancies, however, a few members which include STAT3 and STAT5 are linked to tumor initiation and progression. Other STAT members such as STAT1 and STAT2 are pivotal for antitumor defense and maintenance of an effective and long-term immune response through evolutionarily conserved programs. The effects of JAK/STAT signaling and the persistent activation of STATs in tumor cell survival; proliferation and invasion have made the JAK/STAT pathway an ideal target for drug development and cancer therapy. Therefore, understanding the intricate JAK/STAT signaling in the pathogenesis of solid malignancies needs extensive research. A better understanding of the functionally redundant roles of JAKs and STATs may provide a rationale for improving existing cancer therapies which have deleterious effects on normal cells and to identifying novel targets for therapeutic intervention in solid malignancies.

DARPP-32 promotes ERBB3-mediated resistance to molecular targeted therapy in EGFR-mutated lung adenocarcinoma

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-refractory lung adenocarcinoma (LUAD) progression is a major clinical problem. New approaches to predict and prevent acquired resistance to EGFR TKIs are urgently needed. Here, we show that dopamine and cyclic AMP-regulated phosphoprotein, Mr 32000 (DARPP-32) physically recruits ERBB3 (HER3) to EGFR to mediate switching from EGFR homodimers to EGFR:ERBB3 heterodimers to bypass EGFR TKI-mediated inhibition by potentiating ERBB3-dependent activation of oncogenic signaling. In paired LUAD patient-derived specimens before and after EGFR TKI-refractory disease progression, we reveal that DARPP-32 and kinase-activated EGFR and ERBB3 proteins are overexpressed upon acquired resistance. In mice, DARPP-32 ablation sensitizes gefitinib-resistant xenografts to EGFR TKIs, while DARPP-32 overexpression increases gefitinib-refractory LUAD progression in gefitinib-sensitive lung tumors. We introduce a DARPP-32-mediated, ERBB3-dependent mechanism the LUAD cells use to evade EGFR TKI-induced cell death, potentially paving the way for the development of therapies to better combat therapy-refractory LUAD progression.

MicroRNA‑153‑3p suppresses retinoblastoma cell growth and invasion via targeting the IGF1R/Raf/MEK and IGF1R/PI3K/AKT signaling pathways

Mounting evidence has demonstrated that microRNAs (miRNAs or miRs) play significant roles in various types of human tumors, including retinoblastoma (RB). However, the biological role and regulatory mechanisms of miRNAs in RB remain to be fully elucidated. The present study was designed to identify the regulatory effects of miRNAs in RB and the underlying mechanisms. Differentially expressed miRNAs in RB tissue were screened out based on the Gene Expression Omnibus (GEO) dataset, GSE7072, which revealed that miR-153 in particular, displayed the highest fold change in expression. It was identified that miR-153 was significantly downregulated in RB tissues, and its downregulation was closely associated with a larger tumor base and differentiation. Functional analysis revealed that the overexpression of miR-153 inhibited RB cell proliferation, migration and invasion, and promoted the apoptosis of WERI-RB-1 and Y79 cells. In addition, insulin-like growth factor 1 receptor (IGF1R) was identified as a target of miR-153 in RB cells. More importantly, it was demonstrated that miR-153 upregulation inhibited the expression of its target gene, IGF1R, which inhibited the activation of the Raf/MEK and PI3K/AKT signaling pathways. Collectively, the present study demonstrates for the first time, to the best of our knowledge, that miR-153 functions as a tumor suppressor in RB by targeting the IGF1R/Raf/MEK and IGF1R/PI3K/AKT signaling pathways. Collectively, the findings presented herein demonstrate that miR-153 targets IGF1R and blocks the activation of the Raf/MEK and PI3K/AKT signaling pathway, thus preventing the progression of RB. Thus, this miRNA may serve as a novel prognostic biomarker and therapeutic target for RB.

PP1, PKA and DARPP-32 in breast cancer: A retrospective assessment of protein and mRNA expression

Cyclic AMP–dependent protein kinase A (PKA) and protein phosphatase 1 (PP1) are proteins involved in numerous essential signalling pathways that modulate physiological and pathological functions. Both PP1 and PKA can be inhibited by dopamine‐ and cAMP‐regulated phosphoprotein 32 kD (DARPP‐32). Using immunohistochemistry, PKA and PP1 expression was determined in a large primary breast tumour cohort to evaluate associations between clinical outcome and clinicopathological criteria (n > 1100). In addition, mRNA expression of PKA and PP1 subunits was assessed in the METABRIC data set (n = 1980). Low protein expression of PKA was significantly associated with adverse survival of breast cancer patients; interestingly, this relationship was stronger in ER‐positive breast cancer patients. PP1 protein expression was not associated with patient survival. PKA and PP1 subunit mRNA was also assessed; PPP1CA, PRKACG and PRKAR1B were associated with breast cancer–specific survival. In patients with high expression of DARPP‐32, low expression of PP1 was associated with adverse survival when compared to high expression in the same group. PKA expression and PP1 expression are of significant interest in cancer as they are involved in a wide array of cellular processes, and these data indicate PKA and PP1 may play an important role in patient outcome.

Dopamine D1 Receptor in Cancer

Simple Summary

Circulating hormones and their specific receptors play a significant role in the development and progression of various cancers. This review aimed to summarize current knowledge about the dopamine D1 receptor’s biological role in different cancers, including breast cancer, central nervous system tumors, lymphoproliferative disorders, and other neoplasms. Treatment with dopamine D1 receptor agonists was proven to exert a major anti-cancer effect in many preclinical models. We highlight this receptor’s potential as a target for the adjunct therapy of tumors and discuss possibilities and necessities for further research in this area.

Abstract

Dopamine is a biologically active compound belonging to catecholamines. It plays its roles in the human body, acting both as a circulating hormone and neurotransmitter. It acts through G-protein-coupled receptors divided into two subgroups: D1-like receptors (D1R and D5R) and D2-like receptors (D2R, D3R, D4R). Physiologically, dopamine receptors are involved in central nervous system functions: motivation or cognition, and peripheral actions such as blood pressure and immune response modulation. Increasing evidence indicates that the dopamine D1 receptor may play a significant role in developing different human neoplasms. This receptor’s value was presented in the context of regulating various signaling pathways important in tumor development, including neoplastic cell proliferation, apoptosis, autophagy, migration, invasiveness, or the enrichment of cancer stem cells population. Recent studies proved that its activation by selective or non-selective agonists is associated with significant tumor growth suppression, metastases prevention, and tumor microvasculature maturation. It may also exert a synergistic anti-cancer effect when combined with tyrosine kinase inhibitors or temozolomide. This review provides a comprehensive insight into the heterogeneity of dopamine D1 receptor molecular roles and signaling pathways in human neoplasm development and discusses possible perspectives of its therapeutic targeting as an adjunct anti-cancer strategy of treatment. We highlight the priorities for further directions in this research area.

Systematic Elucidation of the Mechanism of Quercetin against Gastric Cancer via Network Pharmacology Approach

This study was aimed at elucidating the potential mechanisms of quercetin in the treatment of gastric cancer (GC). A network pharmacology approach was used to analyze the targets and pathways of quercetin in treating GC. The predicted targets of quercetin against GC were obtained through database mining, and the correlation of these targets with GC was analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Next, the protein-protein interaction (PPI) network was constructed, and overall survival (OS) analysis of hub targets was performed using the Kaplan–Meier Plotter online tool. Finally, the mechanism was further analyzed via molecular docking of quercetin with the hub targets. Thirty-six quercetin-related genes were identified, 15 of which overlapped with GC-related targets. These targets were further mapped to 319 GO biological process terms and 10 remarkable pathways. In the PPI network analysis, six hub targets were identified, including AKT1, EGFR, SRC, IGF1R, PTK2, and KDR. The high expression of these targets was related to poor OS in GC patients. Molecular docking analysis confirmed that quercetin can bind to these hub targets. In conclusion, this study provided a novel approach to reveal the therapeutic mechanisms of quercetin on GC, which will ease the future clinical application of quercetin in the treatment of GC.

Silencing of miR490-3p by H. pylori activates DARPP-32 and induces resistance to gefitinib

Infection with Helicobacter pylori (H. pylori) is the main risk factor for gastric carcinogenesis. In this study, we investigated the expression, molecular functions, and downstream effectors of miR490-3p in gastric cancer. We used in vitro and in vivo models to investigate the role of H. pylori in regulating miR490-3p, DARPP-32-dependent functions, and therapeutic resistance. Human and mouse neoplastic gastric lesions demonstrated a negative correlation between DARPP-32 and miR490-3p expression (R = -0.58, P < 0.01). This was also detected following infection with H. pylori (R = -0.66, P < 0.01). Molecular assays confirmed DARPP-32 as a direct target of miR490-3p. CHRM2, the host gene of miR490-3p, was hypermethylated and downregulated in neoplastic gastric tissues (P < 0.05). H. pylori induced methylation and downregulation of CHRM2 and miR490-3p. Functionally, the reconstitution of miR490-3p sensitized cancer cells to gefitinib by inactivating DRAPP-32-dependent AKT and STAT3 pathways. Patients with low miR490-3p or high DARPP-32 expression had decreased overall survival (P < 0.05). Hypermethylation-mediated silencing of CHRM2 and miR490-3p by H. pylori increased DARPP-32 expression. Downregulation of miR490-3p in gastric cancer plays a role in gefitinib response by inducing DARPP-32-mediated activation of PI3K/AKT, STAT3 signaling pathways.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.

Gastro-Protective Effects of Calycosin Against Precancerous Lesions of Gastric Carcinoma in Rats

Aim

Gastric cancer is a leading cause of cancer death worldwide. In-depth research of precancerous lesions of gastric carcinoma (PLGC) with malignant transformation potential is a key measure to prevent the development of gastric carcinoma. Recently, calycosin has been shown to have anticancer effects in vitro and in vivo. The molecular mechanism by which calycosin affects PLGC, however, has not yet been elucidated. The purpose of this study was to evaluate the effect and mechanism of calycosin in N‐methyl‐Nʹ‐nitro‐N‐nitrosoguanidine (MNNG)-induced PLGC rats.

Methods

The effects of calycosin in the gastric mucosa of rats with PLGC were evaluated using histopathology and transmission electron microscopy (TEM). For further characterization, the expression levels of integrin β1, nuclear factor kappa B (NF-κB), p-NF-κB, DARPP-32 and signal transducer and activator of transcription 3 (STAT3) were determined by Western blot assay and immunohistochemistry.

Results

Hematoxylin–eosin and high iron diamine–Alcian blue–periodic acid-Schiff (HID-AB-PAS) staining showed that intestinal metaplasia and dysplasia were significantly ameliorated in the calycosin intervention groups compared with the model group. Further, TEM results showed that calycosin intervention tempered microvascular abnormalities and cell morphology of primary and parietal cells in PLGC tissues. The results suggested that calycosin had gastro-protective effects in MNNG-induced PLGC rats. Western blot and immunohistochemistry analysis showed that the increased protein expression levels of NF-κB, p-NF-κB, DARPP-32 and STAT3 in the model group were downregulated by calycosin. The upregulation of integrin β1 expression induced by MNNG was decreased in the calycosin groups.

Conclusion

Collectively, calycosin protected against gastric mucosal injury in part via regulation of the integrin β1/NF-κB/DARPP-32 pathway and suppressed the expression of STAT3 in PLGC. The elucidation of this effect and mechanism of calycosin in PLGC provides a potential therapeutic strategy for treatment of gastric precancerous lesions.

ASCL1-regulated DARPP-32 and t-DARPP stimulate small cell lung cancer growth and neuroendocrine tumour cell proliferation

Background

Small cell lung cancer (SCLC) is the most aggressive form of lung cancer, and new molecular insights are necessary for prognostic and therapeutic advances.

Methods

Dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32) and its N-terminally truncated splice variant, t-DARPP, were stably overexpressed or ablated in human DMS-53 and H1048 SCLC cells. Functional assays and immunoblotting were used to assess how DARPP-32 isoforms regulate SCLC cell growth, proliferation, and apoptosis. DARPP-32-modulated SCLC cells were orthotopically injected into the lungs of SCID mice to evaluate how DARPP-32 and t-DARPP regulate neuroendocrine tumour growth. Immunostaining for DARPP-32 proteins was performed in SCLC patient-derived specimens. Bioinformatics analysis and subsequent transcription assays were used to determine the mechanistic basis of DARPP-32-regulated SCLC growth.

Results

We demonstrate in mice that DARPP-32 and t-DARPP promote SCLC growth through increased Akt/Erk-mediated proliferation and anti-apoptotic signalling. DARPP-32 isoforms are overexpressed in SCLC patient-derived tumour tissue, but undetectable in physiologically normal lung. Achaete-scute homologue 1 (ASCL1) transcriptionally activates DARPP-32 isoforms in human SCLC cells.

Conclusions

We reveal new regulatory mechanisms of SCLC oncogenesis that suggest DARPP-32 isoforms may represent a negative prognostic indicator for SCLC and serve as a potential target for the development of new therapies.

A close relationship between Helicobacter pylori infection and the serum level of CD47 in adults

Objectives: Although Helicobacter pylori (H. pylori) infection is one of the most important risk factors for gastric cancer, the molecular mechanisms underlying the progression of H. pylori-induced gastric cancer remain unclear. Previous studies have demonstrated that Integrin-associated protein (CD47) plays an important role in the development of gastric cancer. Hence, the aim of this study was to preliminarily explore the relationship between CD47 and H. pylori infection.Methods: A total of 417 adults who underwent health checkups at a hospital were recruited in 2018. Serum levels of CD47 and tumor necrosis factor-α (TNF-α) were determined using an enzyme-linked immunosorbent assay. ¹³C urea breath test (¹³C-UBT) was carried out to diagnose H. pylori infection in all participants.Results: Compared with H. pylori-negative participants, H. pylori-positive participants have higher levels of serum CD47 and TNF-α. H. pylori infection, the levels of serum TNF-α and low density lipoprotein (LDL) are the independent predictors of serum level of CD47 in adults. In addition, a potential diagnostic value of serum CD47 level for H. pylori infection has been demonstrated in our study.Conclusion: H. pylori infection is closely associated with the serum level of CD47 in adults, suggesting that H. pylori may promote gastric cancer progression by activating CD47-mediated oncogenic pathways.