Targeting PI3K Signaling in Cancer: A Cautionary Tale of Two AKTs

The Role of Xenobiotics and Anelloviruses in Colorectal Cancer: Mechanisms and Perspectives

Xenobiotics are non-natural chemical compounds to which the human population is exposed. Chronic exposure to certain xenobiotics is associated with various diseases, including cancer development. Anelloviruses (AVs), including Torque Teno Virus (TTV), Torque Teno Mini Virus (TTMV), and Torque Teno Midi Virus (TTMDV), are ubiquitous viruses found in the general population. As no disease has been definitively associated with AVs, they are sometimes referred to as "viruses awaiting a disease". This review explores the potential roles of xenobiotics and AVs in colorectal cancer (CRC) development and suggests a potential interplay between them. Evidence suggests an association between certain xenobiotics (like pesticides, cigarette smoke components, and dietary factors) and CRC, while such an association is less clear for AVs. The high prevalence of AVs suggests these infections alone may be insufficient to disrupt homeostasis; thus, additional factors might be required to promote disease, potentially including cancer.

Time restricted feeding with or without ketosis influences metabolism-related gene expression in a tissue-specific manner in aged rats

Many of the 'hallmarks of aging' involve alterations in cellular and organismal metabolism. One pathway with the potential to impact several traditional markers of impaired function with aging is the PI3K/AKT metabolic pathway. Regulation of this pathway includes many aspects of cellular function, including protein synthesis, proliferation and survival, as well as many downstream targets, including mTOR and FOXOs. Importantly, this pathway is pivotal to the function of every organ system in the human body. Thus, we investigated the expression of several genes along this pathway in multiple organs, including the brain, liver and skeletal muscle, in aged subjects that had been on different experimental diets to regulate metabolic function since mid-life. Specifically, rats were fed a control ad lib diet (AL), a time restricted feeding diet (cTRF), or a time restricted feeding diet with ketogenic macronutrients (kTRF) for the majority of their adult lives (from 8-25 months). We previously reported that regardless of macronutrient ratio, TRF-fed rats in both macronutrient groups required significantly less training to acquire a biconditional association task than their ad lib fed counterparts. The current experiments expand on this work by quantifying metabolism-related gene expression across tissues and interrogating for potential relationships with cognitive performance. AKT expression was significantly reduced in kTRF fed rats within liver and muscle tissue. However, AKT expression within the perirhinal cortex (PER) was higher in kTRF rats with the best cognitive performance. Within CA3, higher levels of FOXO1 gene expression correlated with poorer cognitive performance in ad libitum fed rats. Together, these data demonstrate diet- and tissue-specific alterations in metabolism-related gene expression and their correlation with cognitive status.

Targeting non-histone methylation in gastrointestinal cancers: From biology to clinic

Gastrointestinal (GI) cancers, encompassing a range of malignancies within the digestive tract, present significant challenges in both diagnosis and treatment, reflecting a dire need for innovative therapeutic strategies. This article delves into the profound influence of non-histone methylation on the pathogenesis and evolution of gastrointestinal (GI) cancers. Non-histone proteins, undergoing methylation by enzymes such as Protein Arginine Methyltransferases (PRMTs) and Lysine Methyltransferases (KMTs), play pivotal roles in cellular signaling, metabolism, chromatin remodeling, and other processes crucial for cancer development. This review illuminates the complex mechanisms by which non-histone methylation affects key aspects of tumor biology, including oncogenesis, growth, proliferation, invasion, migration, metabolic reprogramming, and immune escape in GI malignancies. Highlighting recent discoveries, this work underscores the importance of non-histone methylation in cancer biology and its potential as a target for innovative therapeutic strategies aimed at improving outcomes for patients with GI cancers.

HN1-mediated activation of lipogenesis through Akt-SREBP signaling promotes hepatocellular carcinoma cell proliferation and metastasis

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide, with more than 800,000 deaths each year, and its 5-year survival rate is less than 12%. The role of the HN1 gene in HCC has remained elusive, despite its upregulation in various cancer types. In our investigation, we identified HN1's heightened expression in HCC tissues, which, upon overexpression, fosters cell proliferation, migration, and invasion, unveiling its role as an oncogene in HCC. In addition, silencing HN1 diminished the viability and metastasis of HCC cells, whereas HN1 overexpression stimulated their growth and invasion. Gene expression profiling revealed HN1 silencing downregulated 379 genes and upregulated 130 genes, and suppressive proteins associated with the lipogenic signaling pathway networks. Notably, suppressing HN1 markedly decreased the expression levels of SREBP1 and SREBP2, whereas elevating HN1 had the converse effect. This dual modulation of HN1 affected lipid formation, hindering it upon HN1 silencing and promoting it upon HN1 overexpression. Moreover, HN1 triggers the Akt pathway, fostering tumorigenesis via SREBP1-mediated lipogenesis and silencing HN1 effectively curbed HCC tumor growth in mouse xenograft models by deactivating SREBP-1, emphasizing the potential of HN1 as a therapeutic target, impacting both external and internal factors, it holds promise as an effective therapeutic strategy for HCC.

The mechanism of action of myricetin against lung adenocarcinoma based on bioinformatics, in silico and in vitro experiments

Myricetin is a natural flavonoid with anti-cancer and anti-inflammatory effects, but its mechanism for treating lung adenocarcinoma (LUAD) remains unclearly. Therefore, bioinformatics, in silico and in vitro experiments were employed to elucidate this issue in this study. The core targets of myricetin against LUAD were screened by PharmaMapper (v2017), Assistant for Clinical Bioinformatics, STRING (v11.5) and Cytoscape (v3.8.1). Using Kaplan-Meier Plotter (v2022.04.20), UALCAN (v2021.12.13) and GEPIA (v2.0) databases, the correlation between core genes and the prognosis of LUAD patients were analyzed, and the expression levels of core genes were verified. In silico studies were used to analyze the binding energies and sites of myricetin with core genes. The effects of myricetin on H1975 cells were explored through thiazolyl blue (MTT), cell migration, colony formation and western blot assays. A total of 72 potential targets of myricetin against LUAD were identified through bioinformatics. Among the four core targets obtained by multiple networks and in silico assays, the up-regulated MMP9 (HR = 1.14 (1-1.29), logrank P = 0.046) and down-regulated PIK3R1 (HR = 0.58 (0.51-0.66), logrank P < 1E-16) were positively correlated with poor survival outcomes in LUAD patients. In vitro experiments demonstrated that myricetin inhibited the proliferation and migration of H1975 cells, promoting their apoptosis. Myricetin inhibits the proliferation of H1975 cells and induces cell apoptosis through its influence on the expression levels of MMP1, MMP3, MMP9, and PIK3R1 and regulating the multiple pathways these genes participate in. Both MMP9 and PIK3R1 are potential biomarkers for LUAD.

Molecular and Metabolic Phenotyping of Hepatocellular Carcinoma for Biomarker Discovery: A Meta-Analysis

Identifying and translating hepatocellular carcinoma (HCC) biomarkers from bench to bedside using mass spectrometry-based metabolomics and lipidomics is hampered by inconsistent findings. Here, we investigated HCC at systemic and metabolism-centric multiomics levels by conducting a meta-analysis of quantitative evidence from 68 cohorts. Blood transcript biomarkers linked to the HCC metabolic phenotype were externally validated and prioritized. In the studies under investigation, about 600 metabolites were reported as putative HCC-associated biomarkers; 39, 20, and 10 metabolites and 52, 12, and 12 lipids were reported in three or more studies in HCC vs. Control, HCC vs. liver cirrhosis (LC), and LC vs. Control groups, respectively. Amino acids, fatty acids (increased 18:1), bile acids, and lysophosphatidylcholine were the most frequently reported biomarkers in HCC. BAX and RAC1 showed a good correlation and were associated with poor prognosis. Our study proposes robust HCC biomarkers across diverse cohorts using a data-driven knowledge-based approach that is versatile and affordable for studying other diseases.

SPP1 overexpression is associated with poor outcomes in ALK fusion lung cancer patients without receiving targeted therapy

The screening of non-small cell lung cancer (NSCLC) tumors for anaplastic lymphoma receptor tyrosine kinase (ALK) gene rearrangements is important because of the dramatically favorable therapy response to ALK inhibitor. However, the exact mechanism of poor survival in ALK fusion lung cancer patients without receiving targeted therapy is unclear. In this study, total of 521 tumor specimens from Chinese patients with lung cancer were screened for ALK fusion by immunohistochemistry (IHC) and confirmed by fluorescence in situ hybridization (FISH). As results, there were no cases of coexisting EGFR and ALK mutations identified. Fourteen cases (2.7%) harbored ALK fusion, including eight solid adenocarcinomas with signet ring cell features, four acinar adenocarcinomas with cribriform pattern containing mucin, one adenosquamous carcinoma and one micropapillary adenocarcinoma with mucin. Six (42.9%) of fourteen patients with ALK-positive lung cancer had stage IV disease, and five ALK-positive patients treated with platinum-based chemotherapy had poor outcome (all patients were dead and the mean survival time was 12 months), compared to 72 months for patients with ALK inhibitor therapy. Furthermore, Five ALK-positive cases were analyzed by whole exome sequencing (WES) and via direct transcript counting using a digital probe-base (NanoString) to explore the driver genes. Deregulation of PI3K/AKT signaling pathway in ALK-positive lung cancer was demonstrated by WES analysis, and significantly increased mRNA of ALK, ROS1, MET, SPP1 and PI3K signaling pathway was identified by NanoString assay. The concordance between NanoString, IHC and FISH methodologies for detecting ALK fusion was 100%. Significant overexpression of SPP1 protein in ALK-positive lung cancer was confirmed by IHC compared to paired adjacent normal tissues and ALK-negative cancers. Thus we concluded that SPP1 overexpression is associated with poor outcomes for patients with ALK fusion lung cancer without receiving targeted therapy and PI3K/AKT/SPP1 pathway may become the promising targets in patients with aggressive lung cancer.

Phosphoinositide 3-Kinase (PI3K) Reactive Oxygen Species (ROS)-Activated Prodrug in Combination with Anthracycline Impairs PI3K Signaling, Increases DNA Damage Response and Reduces Breast Cancer Cell Growth

RIDR-PI-103 is a novel reactive oxygen species (ROS)-induced drug release prodrug with a self-cyclizing moiety linked to a pan-PI3K inhibitor (PI-103). Under high ROS, PI-103 is released in a controlled manner to inhibit PI3K. The efficacy and bioavailability of RIDR-PI-103 in breast cancer remains unexplored. Cell viability of RIDR-PI-103 was assessed on breast cancer cells (MDA-MB-231, MDA-MB-361 and MDA-MB-453), non-tumorigenic MCF10A and fibroblasts. Matrigel colony formation, cell proliferation and migration assays examined the migratory properties of breast cancers upon treatment with RIDR-PI-103 and doxorubicin. Western blots determined the effect of doxorubicin ± RIDR-PI-103 on AKT activation and DNA damage response. Pharmacokinetic (PK) studies using C57BL/6J mice determined systemic exposure (plasma concentrations and overall area under the curve) and T1/2 of RIDR-PI-103. MDA-MB-453, MDA-MB-231 and MDA-MB-361 cells were sensitive to RIDR-PI-103 vs. MCF10A and normal fibroblast. Combination of doxorubicin and RIDR-PI-103 suppressed cancer cell growth and proliferation. Doxorubicin with RIDR-PI-103 inhibited p-AktS473, upregulated p-CHK1/2 and p-P53. PK studies showed that ~200 ng/mL (0.43 µM) RIDR-PI-103 is achievable in mice plasma with an initial dose of 20 mg/kg and a 10 h T1/2. (4) The prodrug RIDR-PI-103 could be a potential therapeutic for treatment of breast cancer patients.

Network pharmacology and molecular docking reveal the mechanism of Scopoletin against non-small cell lung cancer

AIMS

Scopoletin is a natural anticarcinogenic and antiviral coumarin component. Many studies have proved its anti-cancer effect, and after the preliminary screening of this study, Scopoletin had the best inhibitory effect on Non-small cell lung cancer (NSCLC). But its mechanism for treating NSCLC is still unclear. Therefore, network pharmacology and molecular docking technology were used to explore the potential anti-NSCLC targets and pathways of Scopoletin. The results were verified in vitro.

MAIN METHODS

First, Scopoletin was isolated from Fennel and screened to conduct cell proliferation assay on Human lung cancer cell line A549, Human colon cancer cell line HCT-116 and Human hepatoma cell line HepG2 respectively, through the MTT test. Then, the key targets and related pathways were screened through Protein-protein Interaction (PPI) network and "component-target-pathway" (C-TP) network constructed by network pharmacology. And the key targets were selected to dock with Scopoletin via molecular docking. A549 and Human normal lung epithelial cell BEAS-2B were used to verify the results, finally.

KEY FINDINGS

Through MTT, A549 was chosen as the test cancer cell. From network pharmacology, 16 targets, 27 signaling pathways and 16 GO items were obtained (P < 0.05). The results of PPI network and molecular docking showed that EGFR, BRAF and AKT1 were the key targets of Scopoletin against NSCLC, which were consistent with the western-blot results.

SIGNIFICANCE

Through network pharmacology, molecular docking and experiments in vitro, Scopoletin was verified to against NSCLC through RAS-RAF-MEK-ERK pathway and PI3K/AKT pathway.

PCGF3 promotes the proliferation and migration of non-small cell lung cancer cells via the PI3K/AKT signaling pathway

The Polycomb Group Ring Finger 3 (PCGF3) protein has been reported to be significantly upregulated in pancreatic islet tumors and related to signal transduction; however, its detailed mechanisms and biological roles in other tumors, including non-small cell lung cancer (NSCLC), remain unclear. This study investigated the function of PCGF3 in NSCLC and further elucidated its mechanism of action. The immunohistochemical analysis of 86 selected lung cancer tissues revealed that PCGF3 was highly expressed in NSCLC tissues and positively correlated with lymph node metastasis and p-TNM staging. Additionally, PCGF3 promoted cell proliferation in lung cancer by regulating CyclinB1, CyclinD1, and CDK4 expression, and also promoting their migration by regulating RhoA, RhoC, and CDC42. Furthermore, PCGF3 affected both the proliferation and migration of lung cancer cells by regulating the PI3K/AKT pathway, as verified by inhibiting this pathway using LY294002. The findings of this study suggested that PCGF3 is associated with poor prognosis in patients with NSCLC and could therefore be an important biomarker for treating and preventing NSCLC.

Hydrazinocurcumin and 5-fluorouracil enhance apoptosis and restrain tumorigenicity of HepG2 cells via disrupting the PTEN-mediated PI3K/Akt signaling pathway

Hydrazinocurcumin (HZC), a curcumin analogue, serves as a tumor suppressor in breast cancer and lung cancer. In this study, we investigate the role and mechanism of HZC in regulating HepG2 cell apoptosis and tumorigenicity, and its synergistic effects with 5-fluorouracil (5-Fu). HepG2 cells were treated with HZC and/or 5-Fu to analyze the possible synergistic effects on cell proliferation, apoptosis and cell cycle distribution in vitro using EdU staining, Hoechst staining and flow cytometry, respectively. For mechanistic investigation we used pic, a phosphatase and tensin homolog (PTEN) inhibitor, and in other studies assessed the expression pattern of PTEN and PI3K/Akt signaling pathway-related genes. Additionally, we tested in vivo effects of HZC and 5-Fu treatment on growth of HepG2 cell tumors in nude mice. We found that HZC or 5-Fu induced apoptosis and repressed proliferation of HepG2 cells by upregulating the expression of PTEN and disrupting the PI3K/Akt signaling pathway activation. Moreover, HZC had a higher pro-apoptotic effect than 5-Fu. HZC and 5-Fu induced HepG2 cell apoptosis and inhibited their tumorigenicity in vivo. Inhibition of PTEN expression activated the PI3K/Akt signaling pathway and reversed the protective effects of HZC or 5-Fu. Thus, HZC and 5-Fu increase PTEN, which blocks the PI3K/Akt signaling pathway, ultimately inducing HepG2 cell apoptosis. Importantly, the synergistic combination of HZC and 5-Fu may present promising strategy for the treatment of HCC.

Dietary Carbohydrate Promotes Cell Survival in Cancer Via the Up-Regulation of Fat Mass and Obesity-Associated Gene Expression Level

Cancer cells are mainly dependent on glycolysis for their growth and survival. Dietary carbohydrates play a critical role in the growth and proliferation of cancer and a low-carbohydrate diet may help slow down the growth of tumours. However, the exact mechanisms behind this effect are unclear. This review study aimed to investigate the effect of fat mass and obesity-associated (FTO) gene in the association between dietary carbohydrates and cancer. This study was carried out using keywords such as polymorphism and/or cancer and/or dietary carbohydrate and/or FTO gene. PubMed and Science Direct databases were used to collect all related articles published from 1990 to 2018. Recent studies showed that the level of FTO gene expression in cancer cells is dramatically increased and may play a role in the growth of these cells through the regulation of the cellular metabolic pathways, including the phosphoinositide 3-kinases/protein kinaseB (PI3K/AKT) signaling pathway. Dietary carbohydrate may influence the FTO gene expression by eliminating the inhibitory effect of adenosine monophosphate-activated protein kinase (AMPK) on the FTO gene expression. This review summarised what has been recently discovered about the effects of dietary carbohydrate on cancer cells and tried to determine the mediating role of the FTO gene in these effects.

Dysregulated long non‑coding RNAs in pleomorphic adenoma tissues of pleomorphic adenoma gene 1 transgenic mice

Long non-coding RNAs (lncRNAs) have been proven to serve vital roles in various human diseases. However, their involvement in the development of pleomorphic adenoma (PA) in the salivary gland has yet to be examined. In the present study, microarray analysis of the lncRNA and mRNA expression profiles in pleomorphic adenoma gene 1 (PLAG1) transgenic mice was performed. Next, bioinformatics tools were used to predict the differentially expressed genes associated with PA, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and lncRNA-mRNA co-expression network analyses. Comparison of the transgenic and control mice demonstrated that a total of 9,110 lncRNAs and 7,750 mRNAs were significantly differentially expressed (fold change >2; P<0.05). Subsequently, six lncRNAs were randomly selected for further analysis, and five of these were validated as differentially expressed in PA by quantitative polymerase chain reaction, supporting the methodology employed in the current study. The GO and KEGG enrichment analysis of the differentially expressed mRNAs revealed that these mRNAs were closely associated with a number of processes involved in the development of PA. Furthermore, the lncRNA-mRNA co-expression network indicated that certain lncRNAs may serve vital roles in the pathogenesis of PA by interacting with a number of core genes. Taken together, these results indicated that lncRNAs and mRNAs were differentially expressed in PA tissues obtained from PLAG1 transgenic mice as compared with those from control mice. These differentially expressed lncRNAs may act as novel biomarkers and therapeutic targets for PA.

Identification of CAV1 and DCN as potential predictive biomarkers for lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common histological form of lung cancer that is clinically diagnosed. The aim of this study is to explore the novel genes associated with LUAD tumorigenesis. Comprehensive bioinformatics analyses of the data were obtained from several publicly available databases, such as the Gene Expression Omnibus, the Human Protein Atlas project, and the Cancer Cell Line Encyclopedia. The clinical relevance of these novel genes in LUAD was further examined by immunohistochemistry. We identified the overlapping differentially expressed genes (DEGs) in five independent microarray data sets from the Gene Expression Omnibus database ( GSE75037 , GSE85716 , GSE85841 , GSE63459 , and GSE32867 ). Using the criteria of |log (fold change)| ≥ 1 and P value <0.05, 167 genes were preliminarily validated as co-DEGs. Protein-protein interaction network analysis indicated that caveolin 1 (CAV1) and decorin (DCN) levels were significantly reduced and that these genes were the most promising predictive biomarkers for the occurrence and prognosis of LUAD. A cell proliferation assay indicated that overexpressed CAV1 and DCN could significantly inhibit the proliferation rate of A549 and H157 cells. Additionally, these two downregulated candidate genes were further verified by immunohistochemistry conducted on a LUAD tissue array and comprehensive bioinformatics analyses, including those using the Oncomine platform and the Cancer Cell Line Encyclopedia. Our study demonstrates low levels of CAV1 and DCN in LUAD. An understanding of their functional roles in LUAD biology would give us important insights that would be useful in further investigations.

TREM2 acts as a tumor suppressor in hepatocellular carcinoma by targeting the PI3K/Akt/β-catenin pathway

Triggering receptor expressed on myeloid cells 2 (TREM2) is involved in nonmalignant pathological processes. However, TREM2’s function in malignant diseases, especially in hepatocellular carcinoma (HCC) remains unknown. In the present study, we report that TREM2 is a novel tumor suppressor in HCC. TREM2 expression was obviously decreased in hepatoma cells (especially metastatic HCC cells), and in most human HCC tissues (especially extrahepatic metastatic tumors). Reduced tumor TREM2 expression was correlated with poor prognosis of HCC patients, and with aggressive pathological features (BCLC stage, tumor size, tumor encapsulation, vascular invasion, and tumor differentiation). TREM2 knockdown substantially promoted cell growth, migration, and invasion in vitro and in vivo, while TREM2 overexpression produced the opposite effect. TREM2 suppressed HCC metastasis by inhibiting epithelial-mesenchymal transition, accompanied by abnormal expression of epithelial and mesenchymal markers. Further study revealed that downregulation of TREM2 in HCC was regulated by miR-31-5p. Moreover, by directly interacting with β-catenin, TREM2 attenuated oncogenic and metastatic behaviors by inhibiting Akt and GSK3β phosphorylation, and activating β-catenin. TREM2 suppressed carcinogenesis and metastasis in HCC by targeting the PI3K/Akt/β-catenin pathway. Thus, we propose that TREM2 may be a candidate prognostic biomarker in malignant diseases and TREM2 restoration might be a prospective strategy for HCC therapy.

XB130 Knockdown Inhibits the Proliferation, Invasiveness, and Metastasis of Hepatocellular Carcinoma Cells and Sensitizes them to TRAIL-Induced Apoptosis

Background

XB130 is a recently discovered adaptor protein that is highly expressed in many malignant tumors, but few studies have investigated its role in hepatocellular carcinoma (HCC). Therefore, this study explored the relationship between this protein and liver cancer and investigated its molecular mechanism of action.

Methods

The expression of XB130 between HCC tissues and adjacent nontumor tissues was compared by real-time polymerase chain reaction, immunochemistry, and Western blotting. XB130 silencing was performed using small hairpin RNA. The effect of silencing XB130 was examined using Cell Counting Kit-8, colony assay, wound healing assay, and cell cycle analysis.

Results

We found that XB130 was highly expressed in HCC tissues (cancer tissues vs. adjacent tissues: 0.23 ± 0.02 vs. 0.17 ± 0.02, P < 0.05) and liver cancer cell lines, particularly MHCC97H and HepG2 (MHCC97H and HepG2 vs. normal liver cell line LO-2: 2.35 ± 0.26 and 2.04 ± 0.04 vs. 1.00 ± 0.04, respectively, all P < 0.05). The Cell Counting Kit-8 assay, colony formation assay, and xenograft model in nude mice showed that silencing XB130 inhibited cell proliferative ability both in vivo and in vitro, with flow cytometry demonstrating that the cells were arrested in the G0/G1 phase in HepG2 (HepG2 XB130-silenced group [shA] vs. HepG2 scramble group [NA]: 74.32 ± 5.86% vs. 60.21 ± 3.07%, P < 0.05) and that the number of G2/M phase cells was decreased (HepG2 shA vs. HepG2 NA: 8.06 ± 2.41% vs. 18.36 ± 4.42%, P < 0.05). Furthermore, the cell invasion and migration abilities were impaired, and the levels of the epithelial-mesenchymal transition-related indicators vimentin and N-cadherin were decreased, although the level of E-cadherin was increased after silencing XB130. Western blotting showed that the levels of phosphorylated phosphoinositide 3-kinase (PI3K) and phospho-protein kinase B (p-Akt) also increased, although the level of phosphorylated phosphatase and tensin homolog increased, indicating that XB130 activated the PI3K/Akt pathway. Furthermore, we found that a reduction in XB130 increased liver cancer cell sensitivity to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis.

Conclusions

Our findings suggest that XB130 might be used as a predictor of liver cancer as well as one of the targets for its treatment.

Spermine oxidase is upregulated and promotes tumor growth in hepatocellular carcinoma

AIM

The polyamine catabolic enzyme, spermine oxidase (SMOX) is upregulated in chronic inflammatory conditions and linked to increased reactive oxygen species and DNA damage in various forms of cancers. The present study aims to explore the expression pattern and biological function of SMOX in hepatocellular carcinoma (HCC).

METHODS

We used quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry to examine SMOX expression in four HCC cell lines and 120 HCC clinical samples, and the clinical significance of SMOX was analyzed. The biological function of SMOX on HCC cells was detected both in vitro and in vivo.

RESULTS

Results showed that SMOX was overexpressed in HCC cell lines and clinical HCC tissues. Moreover, SMOX expression levels were gradually increased in normal liver, chronic hepatitis, and HCC tissues. Increased SMOX expression was correlated with poor clinical features of HCC. Patients with positive SMOX expression in tumor tissues indicated worse overall survival (P = 0.008) and shorter relapse-free survival (P = 0.002). Knockdown of SMOX inhibited HCC cell proliferation, arrested cell cycle at S phase, and resulted in an increase of apoptosis. The in vivo study showed that inhibition of SMOX in HCC cells significantly repressed tumor growth in nude mice. Furthermore, we showed that SMOX might exert its function by regulating the phosphatidylinositol 3'-kinase/protein kinase B signaling pathway.

CONCLUSION

Our data indicated that SMOX upregulation could be a critical oncogene in HCC and might serve as a valuable prognostic marker and potential therapeutic target for HCC.

Colorectal carcinogenesis: Insights into the cell death and signal transduction pathways: A review

Colorectal carcinogenesis (CRC) imposes a major health burden in developing countries. It is the third major cause of cancer deaths. Despite several treatment strategies, novel drugs are warranted to reduce the severity of this disease. Adenomatous polyps in the colon are the major culprits in CRC and found in 45% of cancers, especially in patients 60 years of age. Inflammatory polyps are currently gaining attention in CRC, and a growing body of evidence denotes the role of inflammation in CRC. Several experimental models are being employed to investigate CRC in animals, which include the APC^min/+ mouse model, Azoxymethane, Dimethyl hydrazine, and a combination of Dextran sodium sulphate and dimethyl hydrazine. During CRC progression, several signal transduction pathways are activated. Among the major signal transduction pathways are p53, Transforming growth factor beta, Wnt/β-catenin, Delta Notch, Hippo signalling, nuclear factor erythroid 2-related factor 2 and Kelch-like ECH-associated protein 1 pathways. These signalling pathways collaborate with cell death mechanisms, which include apoptosis, necroptosis and autophagy, to determine cell fate. Extensive research has been carried out in our laboratory to investigate these signal transduction and cell death mechanistic pathways in CRC. This review summarizes CRC pathogenesis and the related cell death and signal transduction pathways.

Proteinase-activated receptor 2 promotes tumor cell proliferation and metastasis by inducing epithelial-mesenchymal transition and predicts poor prognosis in hepatocellular carcinoma

AIM

To clarify the role of proteinase-activated receptor 2 (PAR2) in hepatocellular carcinoma, especially in the process of metastasis.

METHODS

PAR2 expression levels were assessed by qRT-PCR and immunohistochemistry (IHC) in patient tissues and in hepatocellular carcinoma cell lines SMMC-7721 and HepG2. Cell proliferation and metastasis were assessed both in vitro and in vitro. Immunoblotting was carried out to monitor the levels of mitogen-activated protein kinase (MAPK) and epithelial-mesenchymal transition markers.

RESULTS

The prognosis was significantly poorer in patients with high PAR2 levels than in those with low PAR2 levels. Patients with high PAR2 levels had advanced tumor stage (P = 0.001, chi-square test), larger tumor size (P = 0.032, chi-square test), and high microvascular invasion rate (P = 0.037, chi-square test). The proliferation and metastasis ability of SMMC-7721 and HepG2 cells was increased after PAR2 overexpression, while knockdown of PAR2 decreased the proliferation and metastasis ability of SMMC-7721 and HepG2 cells. Knockdown of PAR2 also inhibited hepatocellular carcinoma tumor cell growth and liver metastasis in nude mice. Mechanistically, PAR2 increased the proliferation ability of SMMC-7721 and HepG2 cells via ERK activation. Activated ERK further promoted the epithelial-mesenchymal transition of these cells, which endowed them with enhanced migration and invasion ability.

CONCLUSION

These data suggest that PAR2 plays an important role in the proliferation and metastasis of hepatocellular carcinoma. Therefore, targeting PAR2 may present a favorable target for treatment of this malignancy.

Blocking PI3K/AKT signaling inhibits bone sclerosis in subchondral bone and attenuates post-traumatic osteoarthritis

PI3K/AKT signaling is essential in regulating pathophysiology of osteoarthritis (OA). However, its potential modulatory role in early OA progression has not been investigated yet. Here, a mouse destabilization OA model in the tibia was used to investigate roles of PI3K/AKT signaling in the early subchondral bone changes and OA pathological process. We revealed a significant increase in PI3K/AKT signaling activation which was associated with aberrant bone formation in tibial subchondral bone following destabilizing the medial meniscus (DMM), which was effectively prevented by treatment with PI3K/AKT signaling inhibitor LY294002. PI3K/AKT signaling inhibition attenuated articular cartilage degeneration. Serum and bone biochemical analyses revealed increased levels of MMP-13, which was found expressed mainly by osteoblastic cells in subchondral bone. However, this MMP-13 induction was attenuated by LY294002 treatment. Furthermore, PI3K/AKT signaling was found to enhance preosteoblast proliferation, differentiation, and expression of MMP-13 by activating NF-κB pathway. In conclusion, inhibition of PI3K/AKT/NF-κB axis was able to prevent aberrant bone formation and attenuate cartilage degeneration in OA mice.

The chemokine receptor CCR10 promotes inflammation-driven hepatocarcinogenesis via PI3K/Akt pathway activation

G-protein-coupled receptor (GPCR)-related proteins are dysregulated and the GPCR CC-chemokine receptor 10 (CCR10) is significantly upregulated in inflammation-driven HCC. However, CCR10′s role in inflammation-driven hepatocarcinogenesis remains unknown. The aim of this study was to evaluate the role of CCR10 in inflammation-driven hepatocarcinogenesis. Via a targeted gene expression microarray screening alterations in GPCR family gene expression, we found CCR10 to be significantly upregulated in hepatocytes isolated from inflammation-driven human HCC tumors and matching paracancerous tissues. Tetrachloromethane (CCl4)-induced and diethylnitrosamine (DEN)-induced murine models of inflammatory hepatocarcinogenesis displayed significant hepatocellular TNF and CCR10 upregulation. Exogenous TNF applied to HepG2 and LO2 cell lines as well as wild-type (WT) mice significantly upregulated hepatocellular CCR10 expression, Akt phosphorylation, PCNA expression, and hepatocellular proliferation. Additionally, exogenous TNF significantly upregulated secretion of the natural CCR10 ligand-agonist CCL28 from both cell lines. Transgenic CCR10-knockout (CCR10 KO) in DEN-treated mice significantly increased hepatocellular apoptosis levels and significantly lowered compensatory hepatocellular proliferation but did not affect upstream TNF expression. In addition, DEN-treated CCR10 KO mice showed a significantly lower liver weight/body weight ratio, significantly lower liver tumor incidence, and significantly smaller tumors. Moreover, exogenous CCR10 expression significantly raised xenograft tumor growth in Balb/c nude mice. In vitro, CCR10 transfection or CCL28 treatment in HepG2 and LO2 cell lines significantly increased Akt phosphorylation, PCNA expression, and cell proliferation, while CCR10 silencing or Akt inhibition produced the opposite effects. In vivo, hepatocytes isolated from HCC tumor tissue and matching paracancerous tissue in DEN-treated CCR10 KO mice showed significantly lower Akt phosphorylation and PCNA expression relative to WT hepatocytes. In conclusion, inflammation-induced TNF promotes hepatocellular CCR10 expression and downstream PI3K/Akt-mediated hepatocarcinogenesis. CCR10 appears to function as a linkage between TNF stimulation and downstream PI3K/Akt pathway activation and shows promise as a potential therapeutic target for inflammation-driven HCC.

Kctd20 promotes the development of non-small cell lung cancer through activating Fak/AKT pathway and predicts poor overall survival of patients

Kctd20 (potassium channel tetramerization protein domain containing 20) is a positive regulator of Akt signaling. However, the role of Kctd20 during the course of tumorigenesis and development is unclear. Using immunohistochemistry, we demonstrated that, in non-small cell lung cancer (NSCLC) patients, Kctd20 protein expression significantly correlates with advanced TNM stage (P < 0.001), positive status for regional lymph node metastasis (P = 0.019), and poor overall survival (P = 0.013). Proliferation and invasion assays showed that Kctd20 dramatically promotes the proliferation and invasion of NSCLC cells (P = 0.007 and P < 0.001, respectively). Subsequent Western Blot and qPCR experiments revealed an upregulation of Cyclin D1 and downregulation of E-cadherin in Kctd20-overexpressing cells. After depleting Kctd20, downregulaton of Cyclin D1, and upegulation of E-cadherin was observed. After overexpressing Kctd20, the levels of phosphorylated Fak (Tyr397) and Akt (Thr308) increased, while after transfection with Kctd20-siRNA these phosporylated proteins were downregulated. Moreover, in Kctd20-overexpressing cells, treatment with an Akt inhibitor reduced expression of p-Akt and Cyclin D1, enhanced E-cadherin expression, and did not impact p-Fak levels. When Kctd20-overexpressing cells were treated with a Fak inhibitor, the same effects were seen, and the level of p-Akt was reduced. Our results suggest that Kctd20 impacts proliferation and invasion of NSCLC through enhancing Fak (Tyr397) and Akt (Thr 308) phosphorylation. Kctd20 may predict prognosis and be targeted therapeutically in NSCLC.

The Antibiotic Drug Tigecycline: A Focus on its Promising Anticancer Properties

Tigecycline (TIG), the first member of glycylcycline bacteriostatic agents, has been approved to treat complicated infections in the clinic because of its expanded-spectrum antibiotic potential. Recently, an increasing number of studies have emphasized the anti-tumor effects of TIG. The inhibitory effects of TIG on cancer depend on several activating signaling pathways and abnormal mitochondrial function in cancer cells. The aim of this review is to summarize the cumulative anti-tumor evidence supporting TIG activity against different cancer types, including acute myeloid leukemia (AML), glioma, non-small cell lung cancer (NSCLC), among others. In addition, the efficacy and side effects of TIG in cancer patients are summarized in detail. Future clinical trials are also to be discussed that will evaluate the security and validate the underlying the tumor-killing properties of TIG.