shRNA-mediated silencing of Gli2 gene inhibits proliferation and sensitizes human hepatocellular carcinoma cells towards TRAIL-induced apoptosis

Traditional Chinese medicine and natural products in management of hepatocellular carcinoma: Biological mechanisms and therapeutic potential

Hepatocellular carcinoma (HCC), originating from hepatocytes, is the most common type of primary liver cancer. HCC imposes a significant global health burden with high morbidity and mortality, making it a critical public concern. Surgical interventions, including hepatectomy and liver transplantation, are pivotal in achieving long-term survival for patients with HCC. Additionally, ablation therapy, endovascular interventional therapy, radiotherapy, and systemic anti-tumor therapies are commonly employed. However, these treatment modalities are often associated with considerable challenges, including high postoperative recurrence rates and adverse effects. Traditional Chinese medicine (TCM) and natural products have been utilized for centuries as a complementary approach in managing HCC and its complications, demonstrating favorable clinical outcomes. Various bioactive compounds derived from TCM and natural products have been identified and purified, and their mechanisms of action have been extensively investigated. This review aims to provide a comprehensive and up-to-date evaluation of the clinical efficacy of TCM, natural products and their active constituents in the treatment and management of HCC. Particular emphasis is placed on elucidating the potential molecular mechanisms and therapeutic targets of these agents, including their roles in inhibiting HCC cell proliferation, inducing apoptosis and pyroptosis, suppressing tumor invasion and metastasis, and restraining angiogenesis within HCC tissues.

Multifunctional and stimuli-responsive liposomes in hepatocellular carcinoma diagnosis and therapy

Hepatocellular carcinoma (HCC) is the most prevalent type of liver cancer, mainly occurring in Asian countries with an increased incidence rate globally. Currently, several kinds of therapies have been deployed for HCC therapy including surgical resection, chemotherapy, radiotherapy and immunotherapy. However, this tumor is still incurable, requiring novel strategies for its treatment. The nanomedicine has provided the new insights regarding the treatment of cancer that liposomes as lipid-based nanoparticles, have been widely applied in cancer therapy due to their biocompaitiblity, high drug loading and ease of synthesis and modification. The current review evaluates the application of liposomes for the HCC therapy. The drugs and genes lack targeting ability into tumor tissues and cells. Therefore, loading drugs or genes on liposomes can increase their accumulation in tumor site for HCC suppression. Moreover, the stimuli-responsive liposomes including pH-, redox- and light-sensitive liposomes are able to deliver drug into tumor microenvironment to improve therapeutic index. Since a number of receptors upregulate on HCC cells, the functionalization of liposomes with lactoferrin and peptides can promote the targeting ability towards HCC cells. Moreover, phototherapy can be induced by liposomes through loading phtoosensitizers to stimulate photothermal- and photodynamic-driven ablation of HCC cells. Overall, the findings are in line with the fact that liposomes are promising nanocarriers for the treatment of HCC.

Transcriptome analysis reveals molecular mechanisms of lymphocystis formation caused by lymphocystis disease virus infection in flounder (Paralichthys olivaceus)

Lymphocystis disease is frequently prevalent and transmissible in various teleost species worldwide due to lymphocystis disease virus (LCDV) infection, causing unsightly growths of benign lymphocystis nodules in fish and resulting in huge economic losses to aquaculture industry. However, the molecular mechanism of lymphocystis formation is unclear. In this study, LCDV was firstly detected in naturally infected flounder (Paralichthys olivaceus) by PCR, histopathological, and immunological techniques. To further understand lymphocystis formation, transcriptome sequencing of skin nodule tissue was performed by using healthy flounder skin as a control. In total, RNA-seq produced 99.36%-99.71% clean reads of raw reads, of which 91.11%-92.89% reads were successfully matched to the flounder genome. The transcriptome data showed good reproducibility between samples, with 3781 up-regulated and 2280 down-regulated differentially expressed genes. GSEA analysis revealed activation of Wnt signaling pathway, Hedgehog signaling pathway, Cell cycle, and Basal cell carcinoma associated with nodule formation. These pathways were analyzed to interact with multiple viral infection and tumor formation pathways. Heat map and protein interaction analysis revealed that these pathways regulated the expression of cell cycle-related genes such as ccnd1 and ccnd2 through key genes including ctnnb1, lef1, tcf3, gli2, and gli3 to promote cell proliferation. Additionally, cGMP-PKG signaling pathway, Calcium signaling pathway, ECM-receptor interaction, and Cytokine-cytokine receptor interaction associated with nodule formation were significantly down-regulated. Among these pathways, tnfsf12, tnfrsf1a, and tnfrsf19, associated with pro-apoptosis, and vdac2, which promotes viral replication by inhibiting apoptosis, were significantly up-regulated. Visual analysis revealed significant down-regulation of cytc, which expresses the pro-apoptotic protein cytochrome C, as well as phb and phb2, which have anti-tumor activity, however, casp3 was significantly up-regulated. Moreover, bcl9, bcl11a, and bcl-xl, which promote cell proliferation and inhibit apoptosis, were significantly upregulated, as were fgfr1, fgfr2, and fgfr3, which are related to tumor formation. Furthermore, RNA-seq data were validated by qRT-PCR, and LCDV copy numbers and expression patterns of focused genes in various tissues were also investigated. These results clarified the pathways and differentially expressed genes associated with lymphocystis nodule development caused by LCDV infection in flounder for the first time, providing a new breakthrough in molecular mechanisms of lymphocystis formation in fish.

A new 1,2-diketone physalin isolated from Physalis minima and TRAIL-resistance overcoming activity of physalins

A new 1,2-diketone physalin, physalin XII (1), and 13 known compounds were isolated from the methanol extract of Physalis minima whole plant collected in Thailand. Among them, five physalins (2-6) had tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistance overcoming activity, and physalin F (3) was the most active with an IC50 value of 0.39 µM against human gastric adenocarcinoma cell line AGS in the presence of TRAIL (100 ng/mL). An investigation of the TRAIL-resistance overcoming activity of physalins using western blot analysis showed that 3 promoted TRAIL-induced apoptosis by suppressing anti-apoptotic proteins c-FLIP and Bcl-2.

circCD151 promotes GLI2 expression by regulating miR‑30d‑5p and enhancing proliferation, invasion and stemness of lung cancer

To investigate the changes of circular (circ)RNA circCD151 expression in lung cancer tissues and cells and its effects on proliferation, migration and invasion of lung cancer cells. The relative expression levels of circCD151 in lung cancer tissues and lung cancer cells (A549 and NCI‑H292) were determined by reverse transcription‑quantitative PCR. The effects of silencing or upregulation of circCD151 on the activity and clonal forming ability of A549 and NCI‑H292 cells were detected by CCK‑8 and cloning formation experiments. Transwell invasion assay detected the effects of silencing or upregulation of circCD151 on the migration and invasion ability of A549 and NCI‑H292 cells. The regulatory effect of circCD151 on miR‑30d‑5p was detected by dual luciferase reporter gene. The relative expression level of circCD151 in lung cancer tissues was significantly higher compared with that in adjacent tissues. The relative expression level of circCD151 in A549 and NCI‑H292 cells was significantly higher compared with that in human lung epithelial cells. In A549 and NCI‑H292 cells, silencing circCD151 decreased cell activity and clonal formation ability and invasion ability was also significantly decreased. circCD151 was upregulated in A549 and NCI‑H292 cells and the activity and clonal formation ability of A549 and NCI‑H292 cells were significantly increased and the invasion ability was also significantly increased. Double luciferase reporter assay confirmed the ceRNA regulatory mechanism of circCD151/miR‑30d‑5p/GLI2. In the present study, in vivo and in vitro functional studies demonstrated that circCD151 may promote the proliferation, invasion and cell stemness of lung cancer cells. Further molecular mechanism studies demonstrated that circCD151 could promote the malignant proliferation of lung adenocarcinoma by targeting miR‑30d‑5p and upregulating GLI2 expression. From the perspective of circRNA, the present study will provide new clues to the pathogenesis and prognostic judgment of lung adenocarcinoma and provide a new target for clinical treatment.

GLI2 but not GLI1/GLI3 plays a central role in the induction of malignant phenotype of gallbladder cancer

We previously reported that Hedgehog (Hh) signal was enhanced in gallbladder cancer (GBC) and was involved in the induction of malignant phenotype of GBC. In recent years, therapeutics that target Hh signaling have focused on molecules downstream of smoothened (SMO). The three transcription factors in the Hh signal pathway, glioma‑associated oncogene homolog 1 (GLI1), GLI2, and GLI3, function downstream of SMO, but their biological role in GBC remains unclear. In the present study, the biological significance of GLI1, GLI2, and GLI3 were analyzed with the aim of developing novel treatments for GBC. It was revealed that GLI2, but not GLI1 or GLI3, was involved in the cell cycle‑mediated proliferative capacity in GBC and that GLI2, but not GLI1 or GLI3, was involved in the enhanced invasive capacity through epithelial‑mesenchymal transition. Further analyses revealed that GLI2 may function in mediating gemcitabine sensitivity and that GLI2 was involved in the promotion of fibrosis in a mouse xenograft model. Immunohistochemical staining of 66 surgically resected GBC tissues revealed that GLI2‑high expression patients had fewer numbers of CD3+ and CD8+ tumor‑infiltrating lymphocytes (TILs) and increased programmed cell death ligand 1 (PD‑L1) expression in cancer cells. These results suggest that GLI2, but not GLI1 or GLI3, is involved in proliferation, invasion, fibrosis, PD‑L1 expression, and TILs in GBC and could be a novel therapeutic target. The results of this study provide a significant contribution to the development of a new treatment for refractory GBC, which has few therapeutic options.

Transcription activation of circ-STAT3 induced by Gli2 promotes the progression of hepatoblastoma via acting as a sponge for miR-29a/b/c-3p to upregulate STAT3/Gli2

BACKGROUND

Hepatoblastoma (HB) is a common liver malignancy in children. Our previous study has disclosed the crucial role of STAT3 (signal transducer and activator of transcription 3) in HB.

AIM OF THE STUDY

Present study was designed to study the circular RNA (circRNA) STAT3 in HB.

METHODS

Gel electrophoresis revealed the circular characteristics of circ-STAT3. Function assays like EdU, transwell and sphere formation assay disclosed the function of circ-STAT3 in HB cells. Mechanism assays including ChIP, RIP, RNA pull down assay demonstrated the macular mechanism underlying circ-STAT3.

RESULTS

Circ_0043800, which was originated from STAT3, was up-regulated in HB tissues and cells. More importantly, silencing of circ-STAT3 led to the inhibition on HB cell growth, migration and stem-cell characteristics. Circ_0043800 was predominantly located in the cytoplasm of HB cells. Then, circ_0043800 was found to up-regulate STAT3 via sponging miR-29a/b/c-3p. Besides, we identified that STAT3 overexpression partially rescued silenced circ_0043800, while miR-29a/b/c-3p inhibition completely rescued silenced circ_0043800 on HB cellular biological behaviors. Subsequently, Gli2 (GLI family zinc finger 2) was identified as another target of miR-29a/b/c-3p. Circ_0043800 served as a competing endogenous RNA (ceRNA) to up-regulate both Gli2 and STAT3 via sponging miR-29a/b/c-3p. Moreover, we figured out that Gli2 overexpression completely rescued silenced circ_0043800 on HB cell malignant behaviors. After that, we discovered that Gli2 transcriptionally activated circ_0043800. The in-vivo assays further revealed that circ_0043800 promoted HB tumor growth by up-regulation of Gli2 and STAT3.

CONCLUSION

Gli2-induced circ_0043800 served as the ceRNA to promote HB by up-regulation of STAT3 and Gli2 at a miR-29a/b/c-3p dependent manner.

Overexpressed Hsp70 alleviated formaldehyde-induced apoptosis partly via PI3K/Akt signaling pathway in human bronchial epithelial cells

Formaldehyde (FA) is a ubiquitous environmental pollutant, which can induce apoptosis in lung cell and is related to the pathogenesis of asthma, pneumonia, and chronic obstructive pulmonary disease. Heat shock protein 70 (Hsp70) is an ATP-dependent molecular chaperone and exhibits an anti-apoptosis ability in a variety of cells. Previous studies reported that the expression of Hsp70 was induced when organisms were exposed to FA. Whether Hsp70 plays a role in the FA-induced apoptosis and the involved cell signaling pathway remain largely unknown. In this study, human bronchial epithelial cells with overexpressed Hsp70 and the control were exposed to different concentrations of FA (0, 40, 80, and 160 μmol/L) for 24 hours. Apoptosis and the expression levels of PI3K, Akt, p-Akt, MEK, p-MEK, and GLI2 were detected by Annexin-APC/7AAD double-labeled flow cytometry and western blot. The results showed that overexpression of Hsp70 decreased the apoptosis induced by FA and alleviated the decline of PI3k and p-Akt significantly. Inhibitor (LY 294002, a specific inhibitor of PI3K-Akt) test result indicated that PI3K-Akt signaling pathway was involved in the inhibition of FA-induced apoptosis by Hsp70 overexpression and also active in the maintenance of GLI2 level. However, it also suggested that other signaling pathways activated by overexpressed Hsp70 participated in this process, which was needed to be elucidated in further research.

Differential effects of GLI2 and GLI3 in regulating cervical cancer malignancy in vitro and in vivo

Advanced, recurrent, or persistent cervical cancer is often incurable. Therefore, in-depth insights into the molecular mechanisms are needed for the development of novel therapeutic targets and the improvement of current therapeutic strategies. In this study, we investigated the role of GLI2 and GLI3 in the regulation of the malignant properties of cervical cancer. We showed that down-regulation of GLI2, but not GLI3, with an inducible GLI2 shRNA inhibited the growth and migration of cervical cancer cell lines, which could be rescued by ectopic expression of GLI2. GLI2 appeared to support cell growth by regulating the mitosis, but not the apoptosis, of the cervical cancer cells. Mechanistically, these functions of GLI2 were in part mediated by the activation of AKT pathway. Knockdown of GLI2, but not GLI3, also inhibited xenograft growth of cervical cancer cells in vivo. Finally, analysis of TCGA data showed that high levels of GLI2, but not GLI3, conferred a poor prognosis in cervical cancer patients. These observations for the first time suggest that GLI2, but not GLI3, exerts a tumor-promoting role in cervical cancer and may be targeted as a novel therapeutic strategy.

Enhanced radiosensitization of human glioblastoma multiforme cells with phosphorylated peptides derived from Gli2

Glioma-Associated Oncogene Family Zinc Finger 2 (Gli2) seems to be the major nuclear effector of Sonic Hedgehog (SHH) signaling to regulate self-renewal and tumorigenic potential of Glioblastoma multiforme (GBM) cells. Three phosphorylated peptides derived from Gli2 were synthesized and combined with cell-penetrating peptide Tat-(47-57) (AYGRKKRRQRRR). Western Blot was applied to detect the phosphorylation level of Gli2 and cell division protein kinase 6 (CDK6) luciferase reporter was utilized to detect the transcriptional activator function of Gli2. Clonogenic survival assay and apoptosis assay were used to testify the radiosensitization effect. The mixed three phosphorylated peptides derived from Gli2 increased the phosphorylation level of Gli2 and decreased Gli2 transcriptional activator activity significantly than the individually used peptide. The mixed three phosphorylated peptides showed greater radiation-sensitizing effects in GBM cells in clonogenic and survival assay compared with control peptide. We present here a novel rational strategy for developing phosphorylated peptides derived from Gli2 to decrease Gli2 transcriptional activator activity and such administration could radiosensitize GBM.

Advances in differentiation therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignancy of the digestive system, which shows obvious disorders of differentiation. Currently, its pathogenesis is still elusive. Therefore, to figure out the mechanism of disturbed differentiation in HCC is the key to finding out precise therapeutic targets for differentiation therapy. Differentiation therapy of hepatocellular carcinoma refers to making hepatocellular carcinoma cells differentiate into mature hepatocytes, and rebuilding their normal phenotype and normal biological function through promoting HCC cell apoptosis and inhibiting their proliferation in the presence of specific differentiation-inducing agents or signals. In recent years, increasing research results about HCC differentiation therapy have been reported. This article reviews differentiation-inducing agents or targets, differentiation-related signaling pathways and microRNAs, with an aim to provide some clues for HCC differentiation therapy.

Gli2 silencing enhances TRAIL-induced apoptosis and reduces tumor growth in human hepatoma cells in vivo

Our previous studies have showed that Gli2 played a predominant role in proliferation and apoptosis resistance to TRAIL in hepatoma cells. The purpose of this study was to explore whether Gli2 silencing enhances efficiency of TRAIL for hepatoma in vivo. SMMC-7721-shRNA cells were implanted subcutaneously into nude mices and TRAIL was injected into the peritoneal space. TUNEL assay was used to detect apoptosis of tumor cells. The expression of Gli2, c-FLIPL, c-FLIPS, and Bcl-2 protein was determined by immunohistochemistry, respectively. Apoptosis and the level of caspases proteins in SMMC-7721 and HepG2 cells were detected by Flow cytometry and Western blot. Transcriptional activity of c-FLIP induced by Gli2 was measured by luciferase reporter gene assay. The results showed that lower volumes and weights of tumor were found in mice xenografted with SMMC-7721-shRNA cells as compared with control cells in the presence of TRAIL (P < 0.05). TUNEL assay showed significantly higher apoptosis index (AI) in the SMMC-7721-shRNA group than in the control groups (P < 0.05). There were remarkable positive correlations between Gli2 and c-FLIPL, c-FLIPS, Bcl-2 protein expression. Over-expression of c-FLIP or Bcl-2 in HepG2 cells attenuated TRAIL-induced apoptosis via suppression of caspase-8 or caspase-9 activity, respectively. Luciferase reporter gene assay found a regulatory sequence by which Gli2 activated transcription between -1007 to -244 in the c-FLIP promoter region. This study demonstrates that Gli2 showed regulatory activity on transcription of c-FLIP gene, and Gli2 silencing enhances TRAIL-induced apoptosis via down-regulation of c-FLIP and Bcl-2 in human hepatoma cells in vivo.

Pharmacological GLI2 inhibition prevents myofibroblast cell-cycle progression and reduces kidney fibrosis

Chronic kidney disease is characterized by interstitial fibrosis and proliferation of scar-secreting myofibroblasts, ultimately leading to end-stage renal disease. The hedgehog (Hh) pathway transcriptional effectors GLI1 and GLI2 are expressed in myofibroblast progenitors; however, the role of these effectors during fibrogenesis is poorly understood. Here, we demonstrated that GLI2, but not GLI1, drives myofibroblast cell-cycle progression in cultured mesenchymal stem cell-like progenitors. In animals exposed to unilateral ureteral obstruction, Hh pathway suppression by expression of the GLI3 repressor in GLI1+ myofibroblast progenitors limited kidney fibrosis. Myofibroblast-specific deletion of Gli2, but not Gli1, also limited kidney fibrosis, and induction of myofibroblast-specific cell-cycle arrest mediated this inhibition. Pharmacologic targeting of this pathway with darinaparsin, an arsenical in clinical trials, reduced fibrosis through reduction of GLI2 protein levels and subsequent cell-cycle arrest in myofibroblasts. GLI2 overexpression rescued the cell-cycle effect of darinaparsin in vitro. While darinaparsin ameliorated fibrosis in WT and Gli1-KO mice, it was not effective in conditional Gli2-KO mice, supporting GLI2 as a direct darinaparsin target. The GLI inhibitor GANT61 also reduced fibrosis in mice. Finally, GLI1 and GLI2 were upregulated in the kidneys of patients with high-grade fibrosis. Together, these data indicate that GLI inhibition has potential as a therapeutic strategy to limit myofibroblast proliferation in kidney fibrosis.

Heterogeneity of hepatocellular carcinoma contributes to cancer progression

Hepatocellular carcinoma (HCC) is a highly heterogeneous disease displaying differences in angiogenesis, extracellular matrix proteins, the immune microenvironment and tumor cell populations. Additionally, genetic variations and epigenetic changes of HCC cells could lead to aberrant signaling pathways, induce cancer stem cells and enhance tumor progression. Thus, the heterogeneity in HCC contributes to disease progression and a better understanding of its heterogeneity will greatly aid in the development of strategies for the HCC treatment.

Zinc finger protein 139 expression in gastric cancer and its clinical significance

AIM: To investigate the expression of zinc finger protein 139 (ZNF139) in gastric cancer (GC), and to analyze its clinical significance.

METHODS: A total of 108 patients who were diagnosed with GC and underwent surgery between January 2005 and March 2007 were enrolled in this study. Gastric tumor specimens and paired tumor-adjacent tissues were collected and paraffin-embedded, and the clinicopathologic characteristics and prognosis were recorded. The expression of ZNF139, Bcl-2, Bax, and caspase-3 were determined by immunohistochemistry, and apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling. SPSS 13.0 software was used for data processing and analyses, and significance was determined at P < 0.05.

RESULTS: The expression of ZNF139 was stronger in tumors than in tumor-adjacent tissues (66.67% vs 44.44%; P < 0.01). Overexpression of ZNF139 correlated with tumor differentiation, invasion depth, clinical stage, lymphatic metastasis, and blood vessel invasion (all Ps < 0.05). Patients with overexpression of ZNF139 had a poorer prognosis (P < 0.01), and overexpression of ZNF139 was an independent factor for the prognosis of GC patients by a Cox survival analysis (P = 0.02). A negative relationship between ZNF139 and the apoptosis index was observed (r = -0.686; P < 0.01). The expression of Bcl-2 in GC was stronger than in tumor-adjacent tissues (66.67% vs 41.67%), whereas the expression levels of Bax and caspase-3 were lower in primary tumors (54.63% and 47.22%, respectively) than in tumor-adjacent tissues (73.15% and 73.15%, respectively) (all Ps < 0.05). The expression of ZNF139 negatively correlated with caspase-3 (r = -0.370; P < 0.01). The expressions of Bcl-2 and Bax were also negatively correlated (r = -0.231; P = 0.02). The expressions of caspase-3 and Bax protein were positively correlated (r = 0.217; P = 0.024).

CONCLUSION: ZNF139 is related to clinicopathologic characteristics and prognosis of GC. Furthermore, it is overexpressed and involved in apoptosis in GC tissues by regulating caspase-3.

Effect of HMGA2 gene silencing on Wnt/β-Catenin signaling pathway in gastric cancer cells

AIM: To induce HMGA2 gene silencing with shRNAs in gastric cancer cell line MKN-45 and to study the interaction between HMGA2 and the Wnt/β-Catenin signaling pathway.

METHODS: A shRNA eukaryotic expression vector that expresses shRNAs of HMGA2 was constructed and transfected into gastric cancer cell line MKN-45. The mRNA and protein expression of HMGA2 was measured by RT-PCR and Western blot 48 h and 72 h after transfection to evaluate the effect of RNA interference. The mRNA and protein expression of β-Catenin, c-myc and cyclin D1 were also measured by RT-PCR and Western blot.

RESULTS: The expression of HMGA2 mRNA 48 h after transfection was significantly lower in the shHMG-A2-1 group than in the shHMGA2-2 group, shHMGA2-3 group, scrambled group and blank control group (0.58 ± 0.07 vs 0.92 ± 0.13, 0.90 ± 0.16, 1.07 ± 0.14, 1.19 ± 0.09, all P < 0.05), but showed no significant difference among the latter four groups (all P > 0.05). Since HMGA2 expression was most significantly silenced in the shHMGA2-1 group (51.3% at 48 h), the plasmid pLLU2G-shHMGA2-1 was chosen for use in subsequent experiments. The expression of HMGA2 protein 72 h after transfection in the shHMGA2-1 group was significantly lower than that in the scrambled group and blank group (0.11 ± 0.03 vs 0.48 ± 0.12, 0.55 ± 0.08, both P < 0.05). The silencing efficiency of transfection of shHMGA2-1 was 80% at 72 h. After silencing the HMGA2 gene, the expression of β-Catenin, c-myc and cyclin D1 mRNAs and proteins was significantly inhibited in the shHMGA2-1 group compared to the blank control group and the scrambled group (β-Catenin mRNA: 0.53 ± 0.04 vs 1.07 ± 0.02, 0.91 ± 0.02; β-Catenin protein: 0.44 ± 0.05 vs 0.69 ± 0.04, 0.67 ± 0.10; c-myc mRNA: 0.39 ± 0.04 vs 0.88 ± 0.05, 0.84 ± 0.03; c-myc protein: 0.25 ± 0.07 vs 0.75 ± 0.09, 0.66 ± 0.10; cyclin D1 mRNA: 0.31 ± 0.02 vs 0.52 ± 0.03, 0.51 ± 0.01; cyclin D1 protein: 0.12 ± 0.01 vs 0.73 ± 0.12, 0.61 ± 0.07; all P < 0.05).

CONCLUSION: The recombinant plasmid PLLU2G-shHMGA2 could effectively inhibit the expression of HMGA2 gene in gastric cancer cell line MKN-45. Silencing of the HMGA2 gene restrained the expression of β-Catenin and its downstream target genes c-myc and cyclin D1. HMGA2 controls the growth and apoptosis of gastric cancer cells possibly via the Wnt/β-Catenin signal pathway.

Expression of glioma-associated oncogene 2 (Gli 2) is correlated with poor prognosis in patients with hepatocellular carcinoma undergoing hepatectomy

Background

Our previous studies showed that glioma-associated oncogene (Gli)2 plays an important role in the proliferation and apoptosis resistance of hepatocellular carcinoma (HCC) cells. The aim of this study was to explore the clinical significance of Gli2 expression in HCC.

Methods

Expression of Gli2 protein was detected in samples from 68 paired HCC samples, the corresponding paraneoplastic liver tissues, and 20 normal liver tissues using immunohistochemistry. Correlation of the immunohistochemistry results with clinicopathologic parameters, prognosis, and the expression of E-cadherin, N-cadherin, and vimentin were analyzed.

Results

Immunohistochemical staining showed high levels of Gli2 protein expression in HCC, compared with paraneoplastic and normal liver tissues (P < 0.05). This high expression level of Gli2 was significantly associated with tumor differentiation, encapsulation, vascular invasion, early recurrence, and intra-hepatic metastasis (P < 0.05). There was a significantly negative correlation between Gli2 and E-cadherin expression (r = −0.302, P < 0.05) and a significantly positive correlation between expression of Gli2 and expression of vimentin (r = −0.468, P < 0.05) and N-cadherin (r = −0.505, P < 0.05). Kaplan-Meier analysis showed that patients with overexpressed Gli2 had significantly shorter overall survival and disease-free survival times (P < 0.05). Multivariate analysis suggested that the level of Gli2 expression was an independent prognostic factor for HCC.

Conclusions

Expression of Gli2 is high in HCC tissue, and is associated with poor prognosis in patients with HCC after hepatectomy.

Roles of c-FLIP in Apoptosis, Necroptosis, and Autophagy

Cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (c-FLIP) is a major antiapoptotic protein and an important cytokine and chemotherapy resistance factor that suppresses cytokine- and chemotherapy-induced apoptosis. c-FLIP is expressed as long (c-FLIPL), short (c-FLIPS), and c-FLIPR splice variants in human cells. c-FLIP binds to FADD and/or caspase-8 or -10 and TRAIL receptor 5 (DR5). This interaction in turn prevents Death-Inducing Signaling Complex (DISC) formation and subsequent activation of the caspase cascade. c-FLIPL and c-FLIPS are also known to have multifunctional roles in various signaling pathways, as well as activating and/or upregulating several cytoprotective and pro-survival signaling proteins including Akt, ERK, and NF-κB. In addition to its role in apoptosis, c-FLIP is involved in programmed necroptosis (necrosis) and autophagy. Necroptosis is regulated by the Ripoptosome, which is a signaling intracellular cell death platform complex. The Ripoptosome contains receptor-interacting protein-1/Receptor-Interacting Protein-3 (RIP1), caspase-8, caspase-10, FADD, and c-FLIP isoforms involved in switching apoptotic and necroptotic cell death. c-FLIP regulates the Ripoptosome; in addition to its role in apoptosis, it is therefore also involved in necrosis. c-FLIPL attenuates autophagy by direct acting on the autophagy machinery by competing with Atg3 binding to LC3, thereby decreasing LC3 processing and inhibiting autophagosome formation. Upregulation of c-FLIP has been found in various tumor types, and its silencing has been shown to restore apoptosis triggered by cytokines and various chemotherapeutic agents. Hence, c-FLIP is an important target for cancer therapy. This review focuses on (1) the anti-apoptotic role of c-FLIP splice variants in preventing apoptosis and inducing cytokine and chemotherapy drug resistance, as well as its roles in necrosis and autophagy, and (2) modulation of c-FLIP expression as a means to enhance apoptosis and modulate necrosis and autophagy in cancer cells.

Gene regulation is governed by a core network in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide, and the mechanisms that lead to the disease are still relatively unclear. However, with the development of high-throughput technologies it is possible to gain a systematic view of biological systems to enhance the understanding of the roles of genes associated with HCC. Thus, analysis of the mechanism of molecule interactions in the context of gene regulatory networks can reveal specific sub-networks that lead to the development of HCC.

Results

In this study, we aimed to identify the most important gene regulations that are dysfunctional in HCC generation. Our method for constructing gene regulatory network is based on predicted target interactions, experimentally-supported interactions, and co-expression model. Regulators in the network included both transcription factors and microRNAs to provide a complete view of gene regulation. Analysis of gene regulatory network revealed that gene regulation in HCC is highly modular, in which different sets of regulators take charge of specific biological processes. We found that microRNAs mainly control biological functions related to mitochondria and oxidative reduction, while transcription factors control immune responses, extracellular activity and the cell cycle. On the higher level of gene regulation, there exists a core network that organizes regulations between different modules and maintains the robustness of the whole network. There is direct experimental evidence for most of the regulators in the core gene regulatory network relating to HCC. We infer it is the central controller of gene regulation. Finally, we explored the influence of the core gene regulatory network on biological pathways.

Conclusions

Our analysis provides insights into the mechanism of transcriptional and post-transcriptional control in HCC. In particular, we highlight the importance of the core gene regulatory network; we propose that it is highly related to HCC and we believe further experimental validation is worthwhile.

A New Player in the Development of TRAIL Based Therapies for Hepatocarcinoma Treatment: ATM Kinase

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. HCCs are genetically and phenotypically heterogeneous tumors characterized by very poor prognosis, mainly due to the lack, at present, of effective therapeutic options, as these tumors are rarely suitable for radiotherapy and often resistant to chemotherapy protocols. In the last years, agonists targeting the Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL) death receptor, has been investigated as a valuable promise for cancer therapy, based on their selectivity for malignant cells and low toxicity for healthy cells. However, many cancer models display resistance to death receptor induced apoptosis, pointing to the requirement for the development of combined therapeutic approaches aimed to selectively sensitize cancer cells to TRAIL. Recently, we identified ATM kinase as a novel modulator of the ability of chemotherapeutic agents to enhance TRAIL sensitivity. Here, we review the biological determinants of HCC responsiveness to TRAIL and provide an exhaustive and updated analysis of the molecular mechanisms exploited for combined therapy in this context. The role of ATM kinase as potential novel predictive biomarker for combined therapeutic approaches based on TRAIL and chemotherapeutic drugs will be closely discussed.

ShRNA-mediated HMGA2 gene silencing inhibits cell proliferation and promotes apoptosis in human gastric cancer cell line MKN-45

AIM: To investigate the effect of short hairpin RNA (shRNA)-mediated HMGA2 gene silencing on cell growth and apoptosis in human gastric cancer cell line MKN-45.

METHODS: A shRNA eukaryotic expression vector that expresses shRNA targeting the HMGA2 gene was constructed and transfected into MKN-45 cells. HMGA2 protein expression was measured by immunocytochemistry 72 hours after transfection. Cell growth and apoptosis were determined by MTT assay and flow cytometry, respectively.

RESULTS: Compared to the scrambled siRNA group and blank control group, the expression of HMGA2 protein was significantly decreased (171.34 ± 19.61 vs 143.48 ± 19.04, 141.79 ± 18.09, both P < 0.05); cell growth was significantly inhibited (39.32% ± 2.37% vs 5.66% ± 0.63%, P< 0.05); and cell apoptosis was significantly enhanced in the HMGA2-shRNA group (39.67% ± 2.35% vs 4.29% ± 1.33%, 5.05% ± 1.84%, both P < 0.05).

CONCLUSION: ShRNA-mediated HMGA2 gene silencing can effectively induce growth inhibition and apoptosis of MKN-45 cells. HMGA2 might be a potential target for the therapy of gastric cancer.