AIM2 inhibits colorectal cancer cell proliferation and migration through suppression of Gli1

Absent in melanoma 2: a potent suppressor of retinal pigment epithelial-mesenchymal transition and experimental proliferative vitreoretinopathy

Epithelial-to-mesenchymal transition (EMT) is a critical and complex process involved in normal embryonic development, tissue regeneration, and tumor progression. It also contributes to retinal diseases, such as age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR). Although absent in melanoma 2 (AIM2) has been linked to inflammatory disorders, autoimmune diseases, and cancers, its role in the EMT of the retinal pigment epithelium (RPE-EMT) and retinal diseases remains unclear. The present study demonstrated that AIM2 functions as a potent suppressor of RPE cell proliferation and EMT to maintain retinal homeostasis. Transcriptome analysis using RNA-sequencing (RNA-Seq) revealed that AIM2 was significantly downregulated in primary human RPE (phRPE) cells undergoing EMT and proliferation. Consequently, Aim2-deficient mice showed morphological changes and increased FN expression in RPE cells under physiological conditions, whereas AIM2 overexpression in phRPE cells inhibited EMT. In a retinal detachment-induced PVR mouse model, AIM2 deficiency promotes RPE-EMT, resulting in severe experimental PVR. Clinical samples further confirmed the downregulation of AIM2 in the PVR membranes from patients. Kyoto Encyclopedia of Genes and Genome analysis revealed that the PI3K-AKT signaling pathway was significantly related to RPE-EMT and that AIM2 inhibited AKT activation in RPE cells by reducing its phosphorylation. Moreover, treatment with eye drops containing an AKT inhibitor alleviated RPE-EMT and the severity of experimental PVR. These findings provide new insights into the complex mechanisms underlying RPE-EMT and PVR pathogenesis, with implications for rational strategies for potential therapeutic applications in PVR by targeting RPE-EMT.

The Role of the AIM2 Gene in Obesity-Related Glucose and Lipid Metabolic Disorders: A Recent Update

Absent in melanoma 2 (AIM2) is a protein encoded by the AIM2 gene located on human chromosomes, AIM2 can recognize and bind to double stranded DNA (dsDNA), leading to the assembly of the AIM2 inflammasome. The AIM2 inflammasome plays important proinflammation role in many diseases, and can induce pyroptotic cell death. It has also been closely linked to the development and progression of metabolic diseases and can be activated in obesity, diabetes, nonalcoholic fatty liver disease, and atherosclerosis. In this article, we mainly review the role of AIM2 in glucose metabolism, especially in obesity-related disorders of glucose and lipid metabolism, and provide insights to better understand the role of AIM2 in the pathogenesis, and clinical treatment of metabolic disease.

Hedgehog pathway and cancer: A new area (Review)

In years of research on classical pathways, the composition, information transmission mechanism, crosstalk with other pathways, and physiological and pathological effects of hedgehog (HH) pathway have been gradually clarified. HH also plays a critical role in tumor formation and development. According to the update of interpretation of tumor phenotypes, the latest relevant studies have been sorted out, to explore the specific mechanism of HH pathway in regulating different tumor phenotypes through gene mutation and signal regulation. The drugs and natural ingredients involved in regulating HH pathway were also reviewed; five approved drugs and drugs under research exert efficacy by blocking HH pathway, and at least 22 natural components have potential to treat tumors by HH pathway. Nevertheless, there is a deficiency of existing studies. The present review confirmed the great potential of HH pathway in future cancer treatment with factual basis.

NLRP3 and AIM2 inflammasomes expression is modified by LPS and titanium ions increasing the release of active IL-1β in alveolar bone-derived MSCs

Periodontitis and peri-implantitis are inflammatory diseases of infectious etiology that lead to the destruction of the supporting tissues located around teeth or implants. Although both pathologies share several characteristics, it is also known that they show important differences which could be due to the release of particles and metal ions from the implant surface. The activation of the inflammasome pathway is one of the main triggers of the inflammatory process. The inflammatory process in patients who suffer periodontitis or peri-implantitis has been mainly studied on cells of the immune system; however, it is also important to consider other cell types with high relevance in the regulation of the inflammatory response. In that context, mesenchymal stromal cells (MSCs) play an essential role in the regulation of inflammation due to their ability to modulate the immune response. This study shows that the induction of NLRP3 and absent in melanoma 2 (AIM2) inflammasome pathways mediated by bacterial components increases the secretion of active IL-1β and the pyroptotic process on human alveolar bone-derived mesenchymal stromal cells (hABSCs). Interestingly, when bacterial components are combined with titanium ions, NLRP3 expression is further increased while AIM2 expression is reduced. Furthermore, decrease of NLRP3 or AIM2 expression in hABSCs partially reverses the negative effect observed on the progression of the inflammatory process as well as on cell survival. In summary, our data suggest that the progression of the inflammatory process in peri-implantitis could be more acute due to the combined action of organic and inorganic components.

AIM2 fosters lung adenocarcinoma immune escape by modulating PD-L1 expression in tumor-associated macrophages via JAK/STAT3

This work was devised to discuss the effect of AIM2 on the immunosuppression of LUAD tumors, as well as its molecular mechanism. An allograft mouse model was built. Mouse macrophages were isolated and collected. The infiltration level of Mø and expression of M1 Mø, M2 Mø markers, and PD-L1 were assayed by IHC and flow cytometry. Expression levels of M1 Mø and M2 Mø marker genes and PD-L1 were detected by qPCR. The expression of proteins linked with JAK/STAT3 was tested by western blot. CD8+T cells and NK cells were activated in vitro and co-cultured with mouse macrophages, and their cytotoxicity was detected by LDH method. The proportion of CD206+PD-L1+ cells and the activation and proliferation of CD8+T cells were assayed by flow cytometry. Multicolor immunofluorescence was utilized to assay the co-localization of proteins. AIM2 demonstrated a high expression in LUAD, exhibiting a conspicuous positive correlation with the expression of the M2 Mø markers as well as PD-L1. Expression of M1 markers was upregulated after knockdown of AIM2, while M2 markers expression and PD-L1 were downregulated, and the colocalization of proteins linked with PD-L1 and M2 Mø was decreased. The infiltration and cytotoxicity of CD8+T cells and NK cells increased after silencing AIM2. After the knockdown of AIM2, which was enriched in the JAK/STAT3 pathway, the phosphorylation levels of JAK1, JAK2, and STAT3 were reduced, the immune infiltration level of CD8+T cells increased, and the co-localization level of PD-L1 and PD-1 dropped. The activity and proliferation level of CD8+T cells were increased with the reduced PD-1 expression. AIM2 fosters M2 Mø polarization and PD-L1 expression via the JAK/STAT3 pathway. Moreover, AIM2 promotes the immune escape of LUAD via the PD-1/PD-L1 axis. Our work may blaze a trail for the clinical treatment of LUAD.

FUNDC2, a mitochondrial outer membrane protein, mediates triple-negative breast cancer progression via the AKT/GSK3β/GLI1 pathway

Triple-negative breast cancer (TNBC) lacks effective therapeutic targets and has a poor prognosis, easy recurrence and metastasis. It is urgent and important to explore TNBC treatment targets. Through mass spectrometry combined with qRT-PCR validation in luminal A cells and TNBC cells, high-content screening and clinical sample analysis, FUNDC2 was discovered as a novel target. The function of the outer mitochondrial membrane protein FUNDC2 in breast cancer is still unclear. In this study, we find that FUNDC2 expression in TNBC tissues is significantly higher than that in luminal subtype breast cancer tissues. FUNDC2 silencing in TNBC cells significantly reduces cell proliferation, migration and invasion. As demonstrated in vivo using subcutaneous tumor xenografts in mice, FUNDC2 suppression significantly inhibits tumor growth. The underlying mechanism might be mediated by inactivating its downstream signal AKT/GSK3β and GLI1, a key factor of the Hedgehog signaling pathway. Therefore, FUNDC2 may promote TNBC progression and provide a therapeutic target for treating TNBC.

Macrophage IL-1β contributes to tumorigenesis through paracrine AIM2 inflammasome activation in the tumor microenvironment

Intracellular recognition of self and non-self -nucleic acids can result in the initiation of effective pro-inflammatory and anti-tumorigenic responses. We hypothesized that macrophages can be activated by tumor-derived nucleic acids to induce inflammasome activation in the tumor microenvironment. We show that tumor conditioned media (CM) can induce IL-1β production, indicative of inflammasome activation in primed macrophages. This could be partially dependent on caspase 1/11, AIM2 and NLRP3. IL-1β enhances tumor cell proliferation, migration and invasion while coculture of tumor cells with macrophages enhances the proliferation of tumor cells, which is AIM2 and caspase 1/11 dependent. Furthermore, we have identified that DNA-RNA hybrids could be the nucleic acid form which activates AIM2 inflammasome at a higher sensitivity as compared to dsDNA. Taken together, the tumor-secretome stimulates an innate immune pathway in macrophages which promotes paracrine cancer growth and may be a key tumorigenic pathway in cancer. Broader understanding on the mechanisms of nucleic acid recognition and interaction with innate immune signaling pathway will help us to better appreciate its potential application in diagnostic and therapeutic benefit in cancer.

A pyroptosis-related signature predicts prognosis and indicates immune microenvironment infiltration in glioma

BACKGROUND

Glioma, the most common malignant brain tumor, leads to high recurrence rates and disabilities in patients. Pyroptosis is an inflammasomes-induced programmed cell death in response to infection or chemotherapy. However, the role of pyroptosis in glioma has not yet been elucidated.

METHODS

RNA-seq data and clinical information of 660 gliomas and 847 samples were downloaded from the TCGA and CGGA, respectively. Then, data of 104 normal brain tissues was retrieved from the GTEx for differential expression analysis. Twelve pairs of peritumoral tissue and glioma samples were used for validation. Gene alteration status of differentially expressed pyroptosis-related regulators in gliomas was detected in cBioPortal algorithm. Consensus clustering was employed to classify gliomas based on differentially expressed pyroptosis-related regulators. Subsequently, a PS-signature was constructed using LASSO-congressional analysis for clinical application. The immune infiltration of glioma microenvironment (TME) was explored using ESTIMATE, CIBERSORT, and the other immune signatures.

RESULTS

cBioPortal algorithm revealed alteration of these regulators was correlated to better prognosis of gliomas. Then, our study showed that pyroptosis-related regulators can be used to sort out patients into two clusters with distinct prognostic outcome and immune status. Moreover, a PS-signature for predicting the prognosis of glioma patients was developed based on the identified subtypes. The high PS-score group showed more abundant inflammatory cell infiltration and stronger immune response, but with poorer prognosis of gliomas.

CONCLUSION

The findings of this study provide a therapeutic basis for future research on pyroptosis and unravel the relationship between pyroptosis and glioma prognosis. The risk signature can be utilized as a prognostic biomarker for glioma.

Inflammasome signaling in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths in the world. Inflammation is often an underlying risk factor for developing CRC. Maintaining gut homeostasis and balancing inflammation is therefore critical to prevent CRC development. One key class of molecular complexes that impact gut homeostasis are inflammasomes, cytosolic multiprotein immune complexes that assemble upon sensing various intracellular alterations. Inflammasomes regulate inflammation, cell death, cytokine release, signaling cascades, and other cellular processes. Roles for inflammasomes in colitis and colitis-associated CRC have been shown in multiple animal models. The activation of inflammasomes leads to the release of the bioactive forms of interleukin (IL)-1β and IL-18, the inflammasome effector cytokines. These cytokines ensure an optimal inflammatory immune response during colitis and colitis-associated CRC. The activation of some inflammasome sensors, including NLRP3, NLRP1, NLRP6, and Pyrin, provides protection from colitis-associated CRC via effector cytokine-dependent mechanisms. Additionally, activation of other inflammasome sensors, such as AIM2, NLRC4, and NAIPs, provides mostly effector cytokine-independent protection. Inflammasomes can also act as integral components of PANoptosomes, which are multifaceted complexes that integrate components from other cell death pathways and regulate a unique form of innate immune inflammatory cell death called PANoptosis. Furthermore, IRF1, a key regulator of some inflammasomes and PANoptosomes, has been implicated in CRC. It is therefore critical to consider the role of inflammasomes in effector cytokine-dependent and -independent protection as well as their role in PANoptosis to modulate CRC for therapeutic targeting. Here, we discuss the mechanisms of inflammasome activation, the functions of inflammasomes in CRC, and current obstacles and future perspectives in inflammasome and CRC research.

Resveratrol Induces Apoptosis, Suppresses Migration, and Invasion of Cervical Cancer Cells by Inhibiting the Hedgehog Signaling Pathway

To investigate the effect and mechanism of resveratrol on the biological behavior of cervical cancer cells (HeLa cells), the apoptosis, migration, and invasion of HeLa cells were detected by flow cytometry, wound healing, and transwell assays. The expression levels of Hedgehog signal pathway proteins (smoothened (SMO), zinc finger transcription factors (Gli1), and sonic hedgehog homolog (Shh)) were detected by quantitative real-time PCR (qPCR) and western blotting. Compared with that control group, resveratrol (RES) significantly induced apoptosis, inhibited the migration and invasion of the HeLa cells. The expression of SMO, Gli1, and Shh were downregulated in the HeLa cells treated with RES. The Hedgehog agonist purmorphamine (PUR) reversed the RES-induced increase of apoptosis and reduction of migration and invasion in the HeLa cells. In conclusion, RES induced the apoptosis and suppressed the migration and invasion of HeLa cells by inhibiting Hedgehog signal pathway.

PANoptosis-based molecular clustering and prognostic signature predicts patient survival and immune landscape in colon cancer

PANoptosis is a newly-discovered cell death pathway that involves crosstalk and co-ordination between pyroptosis, apoptosis, and necroptosis processes. However, the roles of PANoptosis-related genes (PRGs) in prognosis and immune landscape of colon cancer remain widely unknown. Here, we performed a bioinformatics analysis of expression data of nineteen PRGs identified from previous studies and clinical data of colon cancer patients obtained from TCGA and GEO databases. Colon cancer cases were divided into two PRG clusters, and prognosis-related differentially expressed genes (PRDEGs) were identified. The patient data were then separated into two corresponding distinct gene clusters, and the relationship between the risk score, patient prognosis, and immune landscape was analyzed. The identified PRGs and gene clusters correlated with patient survival and immune system and cancer-related biological processes and pathways. A prognosis signature based on seven genes was identified, and patients were divided into high-risk and low-risk groups based on the calculated risk score. A nomogram model for prediction of patient survival was also developed based on the risk score and other clinical features. Accordingly, the high-risk group showed worse prognosis, and the risk score was related to immune cell abundance, cancer stem cell (CSC) index, checkpoint expression, and response to immunotherapy and chemotherapeutic drugs. Results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that LGR5 and VSIG4 were differentially expressed between normal and colon cancer samples. In conclusion, we demonstrated the potential of PANoptosis-based molecular clustering and prognostic signatures for prediction of patient survival and tumor microenvironment (TME) in colon cancer. Our findings may improve our understanding of the role of PANoptosis in colon cancer, and enable the development of more effective treatment strategies.

Induction of GLI1 by miR-27b-3p/FBXW7/KLF5 pathway contributes to pulmonary arterial hypertension

Glioma-associated oncogene homolog 1 (GLI1), a zinc-finger transcription factor, is upregulated in tumors and promotes cancer cell proliferation and migration. However, whether GLI1 involves in pulmonary artery smooth muscle cells (PASMCs) proliferation and migration and the detailed molecular mechanisms underlying GLI1 in pulmonary arterial hypertension (PAH) are not yet clear. Primary cultured rat PASMCs and monocrotaline (MCT)-induced PAH rats model were applied to address these issues in the present study. We found that the expression of GLI1 was significantly increased in endothelin-1 (ET-1) treated PASMCs, accompanied with the activation of microRNA (miR)-27b-3p/F-box and WD repeat domain containing 7 (FBXW7)/kruppel-like factor 5 (KLF5)/GLI1 pathway through endothelin-1 receptor type A (ETAR). Elevated miR-27b-3p suppressed FBXW7 expression, which led to KLF5 accumulation by decreasing its ubiquitinated degradation, KLF5 further induced GLI1 upregulation leading to PASMCs proliferation and migration. In addition, in MCT-induced PAH rats, targeting ETAR/miR-27b-3p/FBXW7/KLF5/GLI1 pathway effectively prevented the pulmonary vascular remodeling and the development of PAH in rats. Our study indicates that interfering ETAR/miR-27b-3p/FBXW7/KLF5/GLI1 signaling axis might have a potential value in the prevention and treatment of PAH.

GLI-1 polymorphisms of Hedgehog pathway as novel risk and prognostic biomarkers in melanoma patients

In adult organisms, deregulation of the sonic hedgehog (SHH) signaling pathway is significantly correlated with different malignancies. Currently, data associating genetic polymorphisms in the SHH pathway with melanoma are scarce and largely unknown. The objective of our study was to elucidate an association between gene polymorphisms in the SHH pathway and prognosis of melanoma skin cancer patients. The current study investigated the association of PTCH1 (rs357564), SMO (rs2228617) and GLI1 (rs2228224, rs2228226), polymorphisms with melanoma predisposition and prognosis. Single-nucleotide polymorphisms were assessed by TaqMan SNP Genotyping Assays. The study involved 93 melanoma patients and 97 individuals in the control group. Melanoma patients with the variant mutant genotype GG of GLI1 rs2228226 polymorphism had poorer overall survival and recurrence-free survival (P = 0.0001 and P = 0.037, respectively). The multivariate analysis revealed that disease progression [hazard ratio (HR) = 14.434, P = 0.0001] and the GLI1 rs2228226 polymorphism (HR = 4.161, P = 0.006) persisted as independent prognostic factors. Mutated allele carriers (combined heterozygous and mutated genotypes) for GLI1 rs2228224 G and GLI1 rs2228226 G allele significantly increased melanoma risk [odds ratio (OR) = 2.261, P = 0.007; OR = 2.176, P = 0.010]. Our study demonstrated that genetic variants in GLI1, downstream member of the HH signaling pathway, are the risk factors for melanoma susceptibility and it can be a novel marker for melanoma prognosis. As a crucial SHH signaling member, GLI1 can also be regarded as a novel drug target for anti-cancer treatment in melanoma.

Construction and validation of a novel pyroptosis-related signature to predict prognosis in patients with cutaneous melanoma

Skin cutaneous melanoma (SKCM) is one of the most malignant skin cancers and remains a health concern worldwide. Pyroptosis is a newly recognized form of programmed cell death and plays a vital role in cancer progression. We aim to construct a prognostic model for SKCM patients based on pyroptosis-related genes (PRGs). SKCM patients from The Cancer Genome Atlas (TCGA) were divided into training and validation cohorts. We used GSE65904 downloaded from GEO database as an external validation cohort. We performed Cox regression and the least absolute shrinkage and selection operator (LASSO) regression to identify prognostic genes and built a risk score. Patients were divided into high- and low-risk groups based on the risk score. Differently expressed genes (DEGs), immune cell infiltration and immune-related pathways activation were compared between the two groups. We established a model containing 4 PRGs, i.e., GSDMA, GSDMC, AIM2 and NOD2. The overall survival (OS) time was significantly different between the 2 groups. The risk score was an independent predictor for prognosis in both the uni- and multi-variable Cox regressions. Gene ontology (GO) and Kyoto Encylopedia of Genes and Genomes (KEGG) analyses showed that DEGs were enriched in immune-related pathways. Most types of immune cells were highly expressed in the low risk group. All immune pathways were significantly up-regulated in the low-risk group. In addition, low-risk patients had a better response to immune checkpoint inhibitors. Our novel pyroptosis-related gene signature could predict the prognosis of SKCM patients and their response to immune checkpoint inhibitors.

AIM2 inhibits the proliferation, invasion and migration, and promotes the apoptosis of osteosarcoma cells by inactivating the PI3K/AKT/mTOR signaling pathway

Osteosarcoma is a primary bone tumor that mainly occurs in children and adolescents. Absent in melanoma 2 (AIM2) has been demonstrated to be involved in regulating the occurrence and development of cancer, exerting oncogenic and pro-cancer effects; however, its role in osteosarcoma is poorly understood. The present study aimed to explore the function and molecular mechanism of AIM2 in the progression of osteosarcoma. In the present study, AIM2 expression was predicted using the Cancer Cell Line Encyclopedia database and examined in several osteosarcoma cell lines using reverse transcription-quantitative PCR and western blotting. Following AIM2 overexpression, cell proliferation and apoptosis were examined using Cell Counting Kit-8, colony formation and TUNEL staining assays. The expression levels of proteins related to apoptosis, epithelial-mesenchymal transition (EMT) and the PI3K/AKT/mTOR signaling pathway were determined by western blotting. Additionally, cell invasion and migration were assessed using Transwell and wound healing assays. After addition of the PI3K/AKT/mTOR signaling pathway inhibitor LY294002 or activator 740Y-P, cell function analysis was performed. The results demonstrated that AIM2 was expressed at low levels in osteosarcoma cell lines. AIM2 overexpression inhibited proliferation, invasion, migration and EMT, and promoted apoptosis in osteosarcoma cells. Furthermore, the levels of phosphorylated (p)-PI3K, p-AKT and p-mTOR were markedly downregulated following AIM2 overexpression. Furthermore, LY294002 treatment had the same effects as AIM2 upregulation on osteosarcoma cell proliferation, apoptosis, invasion, migration and EMT. By contrast, 740Y-P reversed the effects of AIM2 overexpression on the behavior of osteosarcoma cells. Overall, the findings of the present study demonstrated that AIM2 may inhibit the progression of osteosarcoma by inactivating the PI3K/AKT/mTOR signaling pathway, and suggested that AIM2 may be a promising marker for the treatment of osteosarcoma.

Targeting Cancer Stem Cells by Dietary Agents: An Important Therapeutic Strategy against Human Malignancies

As a multifactorial disease, treatment of cancer depends on understanding unique mechanisms involved in its progression. The cancer stem cells (CSCs) are responsible for tumor stemness and by enhancing colony formation, proliferation as well as metastasis, and these cells can also mediate resistance to therapy. Furthermore, the presence of CSCs leads to cancer recurrence and therefore their complete eradication can have immense therapeutic benefits. The present review focuses on targeting CSCs by natural products in cancer therapy. The growth and colony formation capacities of CSCs have been reported can be attenuated by the dietary agents. These compounds can induce apoptosis in CSCs and reduce tumor migration and invasion via EMT inhibition. A variety of molecular pathways including STAT3, Wnt/β-catenin, Sonic Hedgehog, Gli1 and NF-κB undergo down-regulation by dietary agents in suppressing CSC features. Upon exposure to natural agents, a significant decrease occurs in levels of CSC markers including CD44, CD133, ALDH1, Oct4 and Nanog to impair cancer stemness. Furthermore, CSC suppression by dietary agents can enhance sensitivity of tumors to chemotherapy and radiotherapy. In addition to in vitro studies, as well as experiments on the different preclinical models have shown capacity of natural products in suppressing cancer stemness. Furthermore, use of nanostructures for improving therapeutic impact of dietary agents is recommended to rapidly translate preclinical findings for clinical use.

Advances in immune therapies for the treatment of microsatellite instability‑high/deficient mismatch repair metastatic colorectal cancer (Review)

Microsatellite instability-high/deficient mismatch repair colorectal cancer (MSI-H/dMMR CRC) is a molecular subtype characterized by high-frequency mutations within DNA mismatch repair genes. Defects in the DNA mismatch repair machinery lead to subsequent frame-shift mutations, resulting in the generation of frame-shift peptides that serve as neoantigens. This has translated into exquisite sensitivity to immune checkpoint inhibitors (ICIs) and a significant clinical benefit from immune therapies in this patient population. The present article provides a comprehensive review of the advances in the field of immune therapies for MSI-H/dMMR metastatic CRC, with a focus on the major randomized clinical trials that led to Food and Drug Administration approval of specific ICIs for this population, a detailed review of the molecular background responsible for tumor response, as well as the mechanisms of resistance to ICI therapy. Finally, ongoing investigations of other immunotherapeutic strategies to address and overcome the challenges that currently limit response and long-term response to ICIs were presented.

Rab1A promotes cell proliferation and migration by upregulating Gli1 in colorectal cancer

Rab1A, as a highly conserved small guanosine triphosphatase (GTPase), plays contentious roles in different types of cancers. The role of Rab1A in colorectal cancer (CRC) has been described in previous studies, but the molecular mechanisms of Rab1A in CRC remain far from being addressed. In the present study, we found that Rab1A expression was significantly upregulated in CRC tissues and increased Rab1A expression correlated with tumor size, lymph node metastasis (LNM) and tumor-node-metastasis (TNM) stage of CRC patients. We also found that Rab1A exerts its promotive effect on CRC cell proliferation, migration and EMT progress. Further mechanistic experiments showed that glioma-associated oncogene-1 (Gli1), as a key transcriptional factor of the Hedgehog pathway, was implicated in Rab1A-mediated regulation of CRC cell proliferation and migration. In addition, Rab1A upregulated Gli1 expression through Smoothened homolog (SMO)-independent pathway. Finally, Rab1A activated mechanistic target of rapamycin (mTOR) signaling in CRC cells. Collectively, our results define Rab1A as a novel regulator of Gli1 to promote CRC cell proliferation and migration, and suggest that the Rab1A/mTOR/Gli1 axis may serve as a promising therapeutic target for the treatment of CRC.

Absent in melanoma 2 suppresses gastric cancer cell proliferation and migration via inactivation of AKT signaling pathway

Gastric cancer (GC) is the third leading cause of cancer-related mortality worldwide, and poses a great threat to public health. Absent in melanoma 2 (AIM2), a member of the pyrin-HIN family proteins, plays various roles across different types of cancers. However, the possible role of AIM2 in GC, as well as the underling mechanisms, are equivocal and need to be further explored. Herein, we identified that AIM2 expression was significantly down-regulated in GC tissues. Furthermore, loss of AIM2 was significantly associated with tumor size, lymph node metastasis (LNM) and tumor, node, metastases (TNM) staging, as well as poor prognosis in GC patients. Knockdown of AIM2 in GC cells significantly promoted cellular proliferation and migration, whereas AIM2 overexpression did the opposite. Mechanistically, we discovered that AIM2 regulates the AKT signaling pathway. In fact, the enhanced proliferation and migration ability induced by AIM2 knockdown was partially impaired in cells treated with the AKT inhibitor. Overall, our findings suggests that AIM2 is an independent prognostic marker and highlights a new entry point for targeting the AIM2/AKT signaling axis for GC treatment.

Screening and identification of potential biomarkers and therapeutic drugs in melanoma via integrated bioinformatics analysis

Melanoma is a highly aggressive malignant skin tumor with a high rate of metastasis and mortality. In this study, a comprehensive bioinformatics analysis was used to clarify the hub genes and potential drugs. Download the GSE3189, GSE22301, and GSE35388 microarray datasets from the Gene Expression Omnibus (GEO), which contains a total of 33 normal samples and 67 melanoma samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) approach analyze DEGs based on the DAVID. Use STRING to construct protein-protein interaction network, and use MCODE and cytoHubba plug-ins in Cytoscape to perform module analysis and identified hub genes. Use Gene Expression Profile Interactive Analysis (GEPIA) to assess the prognosis of genes in tumors. Finally, use the Drug-Gene Interaction Database (DGIdb) to screen targeted drugs related to hub genes. A total of 140 overlapping DEGs were identified from the three microarray datasets, including 59 up-regulated DEGs and 81 down-regulated DEGs. GO enrichment analysis showed that these DEGs are mainly involved in the biological process such as positive regulation of gene expression, positive regulation of cell proliferation, positive regulation of MAP kinase activity, cell migration, and negative regulation of the apoptotic process. The cellular components are concentrated in the membrane, dendritic spine, the perinuclear region of cytoplasm, extracellular exosome, and membrane raft. Molecular functions include protein homodimerization activity, calmodulin-binding, transcription factor binding, protein binding, and cytoskeletal protein binding. KEGG pathway analysis shows that these DEGs are mainly related to protein digestion and absorption, PPAR signaling pathway, signaling pathways regulating stem cells' pluripotency, and Retinol metabolism. The 23 most closely related DEGs were identified from the PPI network and combined with the GEPIA prognostic analysis, CDH3, ESRP1, FGF2, GBP2, KCNN4, KIT, SEMA4D, and ZEB1 were selected as hub genes, which are considered to be associated with poor prognosis of melanoma closely related. Besides, ten related drugs that may have therapeutic effects on melanoma were also screened. These newly discovered genes and drugs provide new ideas for further research on melanoma.