Apoptosis In Liver Cancer Cells Research Articles

HMQ-T-B10 induces human liver cell apoptosis by competitively targeting EphrinB2 and regulating its pathway.

Hepatocellular carcinoma (HCC) is a highly prevalent cancer worldwide and it is necessary to discover and develop novel preventive strategies and therapeutic approaches for HCC. Herein, we report that EphrinB2 expression is correlated with liver cancer progression. Moreover, by using phosphorylated proteomics array, we reveal a pro‐apoptosis protein whose phosphorylation and activation levels are up‐regulated upon EphrinB2 knockdown. These results suggest that EphrinB2 may act as an anti‐apoptotic protein in liver cancer cells. We also explored the therapeutic potential of HMQ‐T‐B10 (B10), which was designed and synthesized in our laboratory, for HCC and its underlying mechanisms in vitro and in vivo. Our data demonstrate that B10 could bind EphrinB2 and show inhibitory activity on human liver cancer cells. Moreover, induction of human liver cancer cell apoptosis by B10 could be augmented upon EphrinB2 knockdown. B10 inhibited HCC cell growth and induced HCC cell apoptosis by repressing the EphrinB2 and VEGFR2 signalling pathway. Growth of xenograft tumours derived from Hep3B in nude mice was also significantly inhibited by B10. Collectively, these findings highlight the potential molecular mechanisms of B10 and its potential as an effective antitumour agent for HCC.

Matrine promotes liver cancer cell apoptosis by inhibiting mitophagy and PINK1/Parkin pathways.

Matrine is a natural alkaloid isolated from the root and stem of the legume plant Sophora. Its anti-proliferative and pro-apoptotic effects on several types of cancer have been well-documented. However, the role of matrine in regulating mitochondrial homeostasis, particularly mitophagy in liver cancer apoptosis, remains uncertain. The aim of our study was to explore whether matrine promotes liver cancer cell apoptosis by modifying mitophagy. HepG2 cells were used in the study and treated with different doses of matrine. Cell viability and apoptosis were determined by MTT assay, TUNEL staining, western blotting, and LDH release assay. Mitophagy was monitored by immunofluorescence assay and western blotting. Mitochondrial function was assessed by immunofluorescence assay, ELISA, and western blotting. The results of our study indicated that matrine treatment dose-dependently reduced cell viability and increased the apoptotic rate of HepG2 cells. Functional studies demonstrated that matrine treatment induced mitochondrial dysfunction and activated mitochondrial apoptosis by inhibiting protective mitophagy. Re-activation of mitophagy abolished the pro-apoptotic effects of matrine on HepG2 cells. Molecular investigations further confirmed that matrine regulated mitophagy via the PINK1/Parkin pathways. Matrine blocked the PINK1/Parkin pathways and repressed mitophagy, whereas activation of the PINK1/Parkin pathways increased mitophagy activity and promoted HepG2 cell survival in the presence of matrine. Together, our data indicated that matrine promoted HepG2 cell apoptosis through a novel mechanism that acted via inhibiting mitophagy and the PINK1/Parkin pathways. This finding provides new insight into the molecular mechanism of matrine for treating liver cancer and offers a potential target to repress liver cancer progression by modulating mitophagy and the PINK1/Parkin pathways.

RBM38 plays a tumor-suppressor role via stabilizing the p53-mdm2 loop function in hepatocellular carcinoma

BackgroundMisregulation of the p53-mdm2 loop function is a major mechanism to promote hepatocellular carcinoma (HCC). RBM38, a member of the RNA recognition motif (RRM) family of RNA binding proteins (RBPs), plays a fundamental role in the posttranscriptional control of gene expression and regulatory functions in human tumors. A novel RBM38-p53-mdm2 autoregulatory feedback loop has been demonstrated. However, its mechanistic role in HCC remains unclear.MethodsIn the present study, we investigated the role and molecular mechanism of misregulation in the p53-mdm2 loop function by RBM38 in HCC. First we investigated the correlation of RBM38 activity and p53-mdm2 loop function in liver cancer cells and HCC tissues by western blot and quantitative RT-PCR. We then conducted functional assays to investigate the molecular roles of RBM38 in inhibiting liver cancer cells aggressiveness in vitro and suppressing tumorigenicity in vivo.ResultsWe observed RBM38 protein expression was commonly silenced coupled with increased mdm2 and decreased wild type (wt) p53 in liver cancer cells and HCC tissues compared to the corresponding normal liver cells and adjacent liver tissues. RBM38 mRNA level was significantly lower in HCC than adjacent liver tissues, whereas mdm2 and wtp53 mRNA levels were similar between HCC and adjacent liver tissues. This implied that deactivation of RBM38 could disrupt the p53-mdm2 loop and promote HCC, even though p53 and mdm2 transcript amounts were stable. Then, we generated stable liver cancer cell lines with overexpressed RBM38 (RBM38-OE) and found that up-regulation of RBM38 could inhibit mdm2 and restore wtp53 expression. Luciferase assay shown that RBM38 destabilized the mdm2 transcript through binding to multiple AU-/U-rich elements in mdm2 3’-UTR. Furthermore, functional assays showed that ectopic expression of RBM38 could induce liver cancer cell apoptosis and senescence, inhibit proliferation and colony growth, and suppress migration and invasion in vitro. Lastly, RBM38 could suppress HCC tumorigenicity in vivo.ConclusionOur findings suggested that RBM38 may be a core contributor in stabilizing the p53-mdm2 loop function to prevent HCC, and a potential novel target to provide a therapeutic strategy for HCC by inhibiting mdm2 and rescuing p53 from inactivation.

Photoperiodic Flower Mimicking Metallic Nanoparticles for Image-Guided Medicine Applications.

Nanoradiosensitizers have been developed to enhance localization and precision of therapeutic radiation delivery. A specific volume of comprising surface atoms is known to be the radiosensitizing region. However, the shape-dependent local dose enhancement of nanoparticles is often underestimated and rarely reported. Here, a noble metal nanostructure, inspired by the photoperiodic day-flowers, was synthesized by metal reduction with bile acid molecules. The impact of high surface area of day-flowermimicking metallicnanoparticles (D-NP) on radiosensitizing effect was demonstrated with assays for ROS generation, cellular apoptosis, and clonogenic survival of human liver cancer cells (HepG2) cells. In comparison with lower-surface-area spherical night-flower mimickingmetallicnanoparticles (N-NP), exposure of our D-NP to external beam radiation doses led to a significant increase in reactive oxygen species (ROS) production and radiosensitizing cell cycle synchronization, resulting in an enhanced cancer-cell-killing effect. In clonogenic survival studies, dose-enhancing factor (DEF) of D-NP was 16.5-fold higher than N-NP. Finally, we demonstrated in vivo feasibility of our D-NP as a potent nanoradiosensitizer and CT contrast agent for advanced image-guided radiation therapy.

Novel oxazolinoanthracyclines as tumor cell growth inhibitors-Contribution of autophagy and apoptosis in solid tumor cells death.

Chemical modification of known, effective drugs are one method to improve the chemotherapy of tumors. We reported ability of oxazoline analogs of doxorubicin (O-DOX) and daunorubicin (O-DAU) to induce apoptosis and autophagy in ovarian and liver cancer cells. Reactive oxygen and nitrogen species (ROS and RNS, respectively), together with intracellular calcium-mediated downstream signaling, are essential for the anticancer effect of these new anthracycline analogs. The changes of mitochondrial membrane potential and induction of the ceramide pathway suggests that these compounds induce cell death by apoptosis. In addition, a significant increase of autophagosome formation was observed by fluorescence assay and acridine orange staining, indicating that the new analogs also induce autophagic cell death. Compared to free DOX- and DAU-treated cells, we observed inhibition of colony formation and migration, a time-dependency between ROS/RNS levels and a greater fall in mitochondrial membrane potential. Altogether, our research broadens the base of molecular oxazolinoanthracyclines targets and reveals that derivatives mediated oxidative stress, ceramide production and increase in intracellular calcium level by mitochondria. Furthermore, our data highlight the importance of mitochondria that simultaneously assume the role of activator of autophagy and apoptosis signals.

Compound K Induces Endoplasmic Reticulum Stress and Apoptosis in Human Liver Cancer Cells by Regulating STAT3.

The ginsenoside compound K (20-O-β-d-glucopyranosyl-20(S)-protopanaxadiol; CK) is an intestinal bacterial metabolite of ginseng protopanaxadiol saponin that has been reported to induce apoptosis in many cancer cells; however, the precise mechanisms of its activity in human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we demonstrated that CK inhibited the growth and colony formation of HepG2 and SMMC-7721 cells, phenotypes that were mediated by inducing apoptosis. Meanwhile, CK showed lower toxicity in normal hepatoma cells. After treating HepG2 and SMMC-7721 cells with CK, p-STAT3 levels decreased, the three branches of the unfolded protein response were activated, and levels of endoplasmic reticulum stress (ERS)-related proteins were increased. We also revealed that CK decreased the DNA-binding capacity of STAT3. Moreover, silencing STAT3 with CRISPR/Cas9 technology enhanced CK-induced ERS and apoptosis. Finally, we showed that CK inhibited the growth of liver cancer xenografts with little toxicity. Mice bearing human HCC xenografts that were treated with CK showed increased GRP78 expression and decreased p-STAT3 levels. Taken together, these data showed that CK induced ERS and apoptosis by inhibiting p-STAT3 in human liver cancer cells; thus, CK might be a potential therapeutic candidate for human HCC.

Taraxasterol suppresses the growth of human liver cancer by upregulating Hint1 expression.

Taraxasterol inhibits growth and induces apoptosis in human liver cancer cells. Taraxasterol enhances Hint1 expression by promoting demethylation in Hint1 promoter. Taraxasterol increases Hint1 levels to regulate Bax, Bcl2, and cyclinD1 expression. The effects of Taraxasterol are abrogated by Hint1 silencing in liver cancer cells. Taraxasterol inhibits the growth of subcutaneously implanted liver cancers in mice.

Anesthetic effects of isoflurane and the molecular mechanism underlying isoflurane‑inhibited aggressiveness of hepatic carcinoma.

Anesthesia is produced by drugs or other methods, and refers to the attenuation of pain via reversible suppression of neuronal transmission in the central and peripheral nervous systems, during surgery. Clinical investigations have indicated that the anesthetic action of isoflurane is efficient to alleviate pain during tumor resection clinical trials. In addition, it has been reported that isoflurane can induce caspase-3 activation and is associated with apoptosis of tumor cells. The present study investigated the anesthetic effects and molecular mechanisms underlying isoflurane-induced apoptosis in patients with hepatic carcinoma. Furthermore, the pain of patients with hepatic carcinoma was evaluated during the perioperative period according to the pain index. The apoptotic rate of hepatic carcinoma cells was analyzed in tumor tissues using TUNEL assay. The expression levels of apoptosis-associated proteins were detected in liver cancer cells following anesthesia in patients. Phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) and nuclear factor (NF)-κB signaling pathways were also analyzed in liver cancer cells following treatment with isoflurane. The results demonstrated that isoflurane inhibited growth and decreased viability of liver cancer cells in vitro and in vivo. In addition, the apoptotic rate was increased in cells obtained from isoflurane-treated patients. The results also demonstrated that isoflurane upregulated the expression levels of proapoptotic genes and downregulated anti-apoptotic mRNA expression. In addition, a molecular mechanism analysis indicated that isoflurane inhibited PI3K and AKT expression in liver cancer cells. Isoflurane also induced caspase-3 activation in liver cancer cells. Furthermore, isoflurane treatment attenuated NF-κB activity and inhibited migration and invasion of liver cancer cells. In conclusion, these findings indicated that isoflurane treatment efficiently attenuated surgical pain and inhibited tumor aggressiveness via regulation of NF-κB activity and the PI3K/AKT signaling pathway, thus suggesting that isoflurane is an efficient anesthetic drug that induces pain remission and promotes apoptosis of liver cancer cells.

Hiwi overexpression does not affect proliferation, migration or apoptosis of liver cancer cells in vitro or in vivo.

Piwi like RNA-mediated gene silencing 1 (Hiwi) is a human homolog of the Piwi gene family that has been reported to be upregulated in hepatocellular carcinoma (HCC). The present study aimed to investigate the role of Hiwi in the initiation and development of HCC in vitro and in vivo. Adenovirus-mediated Hiwi overexpression was established in primary murine hepatocytes and SMMC7721 HCC cells. Cell viability and proliferation were assessed using MTT and EdU assays, respectively. Cell migration was measured using a scratch migration assay. The cell cycle was assessed using flow cytometry, and the expression of genes associated with the epithelial mesenchymal transition (EMT) was assessed using reverse transcription-quantitative polymerase chain reaction. SMMC7721 cells that stably express Hiwi were also generated and injected subcutaneously into the nude mice, and tumor growth was examined. Recombinant adenovirus encoding green fluorescent protein or Hiwi was delivered by injection into the tail vein, and its effect on murine hepatocyte gene expression was studied. The present study revealed that the overexpression of Hiwi did not affect the proliferation or migration of liver cancer cells and failed to suppress perifosine- or doxorubicin-induced apoptosis in vitro. The tumors of mice that were injected with Hiwi-expressing SMMC7721 cells were not significantly larger compared with mice that were injected with control SMMC7721 cells. Hiwi overexpression did not noticeably alter the expression of genes involved in EMT, either in vitro or in vivo. The results of the present study indicate that although expression of Hiwi is associated with HCC development and progression in the clinic, it does not act as an oncogene in liver cancer cells.

Cinchonine activates endoplasmic reticulum stress-induced apoptosis in human liver cancer cells.

Cinchonine is a natural compound present in Cinchona bark. It exerts multidrug resistance reversal activity and synergistic apoptotic effect with paclitaxel in uterine sarcoma cells. Whether cinchonine is effective against human liver cancer, however, remains elusive. A total of five liver cancer cell lines including Bel-7402, MHCC97H, HepG2, Hep3B and SMCC7721 were used. The anti-proliferative effects of cinchonine on these liver cancer cell lines were assessed by MTT assay. The apoptotic effects of cinchonine on liver cancer cell lines were assessed by flow cytometry with Annexin V/propidium iodide assay. Caspase-3 activation, poly (ADP-Ribose) polymerase (PARP) cleavage as well as the endoplasmic-reticulum (ER) stress response was detected by western blotting. Balb/c-nude mice bearing HepG2 xenograft tumors were used to evaluate the in vivo antitumor effect of cinchonine. It was demonstrated that cinchonine inhibited cell proliferation and promoteed apoptosis in liver cancer cells in a dose-dependent manner. Cinchonine promoted caspase-3 activation and PARP1 cleavage in liver cancer cells. Furthermore, cinchonine activated the ER stress response by upregulating GRP78 and promoting PERK and Eukaryotic Translation Initiation Factor 2 α phosphorylation. The Balb/c-nude mice experiment revealed that cinchonine suppressed HepG2 xenograft tumor growth in mice. The findings indicated that cinchonine promoted ER stress-induced apoptosis in liver cancer cells and suggested that cinchonine may have a potential beneficial effect for liver cancer treatment.

Isovitexin (IV) induces apoptosis and autophagy in liver cancer cells through endoplasmic reticulum stress

Liver cancer is a leading cause of cancer death worldwide, and novel chemotherapeutic drugs to suppress liver cancer are urgently required. Isovitexin (IV), a glycosylflavonoid, is extracted from rice hulls of Oryza sativa, and has various biological activities. However, the anti-tumor effect of IV against liver cancer has not yet been demonstrated in vitro or in vivo. In the present study, we showed that IV significantly suppressed the growth of liver cancer cells. Mechanistic studies indicated that IV induced apoptosis by the mitochondrial apoptotic pathway, as evidenced by the increase of Bax, cleaved Caspase-3, poly (ADP-ribose) polymerase (PARP), and cytoplasm Cyto-c released from mitochondria. In addition, IV resulted in autophagy in liver cancer cells, supported by the enhancement of LC3II, autophagy-related protein (Atg) 3, Atg5 and Beclin1. Suppressing autophagy using bafilomycin A1 (BFA) or siRNA Atg-5 reduced apoptotic cells in IV-treated cells, demonstrating that autophagy induction regulated apoptosis. Moreover, IV was found to cause endoplasmic reticulum (ER) stress in liver cancer cells, along with the promotion of ER stress-related molecules, including inositol-requiring enzyme 1α (IRE1α), X-box-binding protein-1s (XBP-1s), C/EBP homologous protein (CHOP) and glucose-regulated protein (GRP)-78. Of note, inhibition of ER stress by use of its inhibitor, tauroursodeoxycholate (TUDCA), significantly reversed IV-induced apoptosis and autophagy. In vivo, IV treatment showed significant tumor growth inhibition compared to the non-treated group. IV could therefore be a strong candidate for liver cancer prevention.

Propranolol suppresses the proliferation and induces the apoptosis of liver cancer cells.

An increasing amount of evidence indicates that the inhibition of β adrenergic signaling can result in the inhibition of tumor growth. However, the role of propranolol in liver cancer and the underlying mechanism remain to be elucidated. The present study aimed to investigate the role of propranolol in liver cancer cell lines and provide evidence for further clinical study. Propranolol was added at different concentrations to HepG2 and HepG2.2.15 liver cancer cells and HL-7702 normal human liver cells. The proliferation of the cell lines was monitored by live-cell imaging at a range of time intervals. Immunofluorescence using DAPI and Hoechst 33342/propidium iodide (PI) staining, Annexin V-FITC/PI double-staining flow cytometry, western blotting and reverse transcription-quantitative polymerase chain reaction were used to investigate the effect of propranolol on liver cancer cell apoptosis. The proliferation of HepG2 and HepG2.2.15 cells was inhibited by 40 and 80 µmol/l propranolol. However, the proliferation of HL-7702 cells was not affected by <160 µmol/l propranolol. Propranolol treatment decreased the expression of adrenergic receptor β-2 to a greater extent than adrenergic receptor β-1, and induced apoptosis in the liver cancer cells. The apoptotic rates of HepG2 and HepG2.2.15 cells increased following treatment with propranolol, while the apoptotic rate of HL-7702 cells was not affected. Propranolol promoted poly (ADP-ribose) polymerase cleavage and decreased the expression of full-length caspase-3 in liver cancer cell lines; it induced S-phase arrest in HepG2 and HepG2.2.15 cell lines, while HL-7702 cells were arrested at the G0/G1 phase of the cell cycle. Thus, it was demonstrated that propranolol inhibited proliferation, promoted apoptosis and induced S-phase arrest in HepG2 and HepG2.2.15 cells.

Metabolic reprogramming by PCK1 promotes TCA cataplerosis, oxidative stress and apoptosis in liver cancer cells and suppresses hepatocellular carcinoma.

Phosphoenolpyruvate carboxykinase (PEPCK or PCK) catalyzes the first rate-limiting step in hepatic gluconeogenesis pathway to maintain blood glucose levels. Mammalian cells express two PCK genes, encoding for a cytoplasmic (PCPEK-C or PCK1) and a mitochondrial (PEPCK-M or PCK2) isoforms, respectively. Increased expressions of both PCK genes are found in cancer of several organs, including colon, lung and skin, and linked to increased anabolic metabolism and cell proliferation. Here, we report that the expressions of both PCK1 and PCK2 genes are downregulated in primary hepatocellular carcinoma (HCC) and low PCK expression was associated with poor prognosis in patients with HCC. Forced expression of either PCK1 or PCK2 in liver cancer cell lines results in severe apoptosis under the condition of glucose deprivation and suppressed liver tumorigenesis in mice. Mechanistically, we show that the proapoptotic effect of PCK1 requires its catalytic activity. We demonstrate that forced PCK1 expression in glucose-starved liver cancer cells induced TCA cataplerosis, leading to energy crisis and oxidative stress. Replenishing TCA intermediate α-ketoglutarate or inhibition of reactive oxygen species production blocked the cell death caused by PCK expression. Taken together, our data reveal that PCK1 is detrimental to malignant hepatocytes and suggest activating PCK1 expression as a potential treatment strategy for patients with HCC.

Deregulation of microRNA-193b affects the proliferation of liver cancer via myeloid cell leukemia-1.

Deregulation of microRNA (miR)-193b has been revealed to be associated with the proliferation of liver cells. However, the interaction between miR-193b and their targets inducing liver cancer remains largely unknown. The aim of the present study was to investigate the hypothesis that miR-193b affects the proliferation of liver cancer cells. In the present study, the overall survival of patients with liver cancer and low fold change of miR-193b was higher compared with that of patients with liver cancer patients and high fold change of miR-193b. The expression level of myeloid cell leukemia-1 (Mcl-1) in patients with liver cancer was lower compared with in the control group. The results of the present study demonstrated that downregulation of miR-193b suppressed the proliferation and induced apoptosis of liver cancer cells, and inhibited the Mcl-1 protein expression level in liver cancer cells. Upregulation of miR-193b increased cell proliferation and decreased apoptosis of liver cancer cells and promoted the expression level of Mcl-1 protein. The results of the present study demonstrated that the expression of miR-193b as a novel tumor suppressor serves an important role in the proliferation of liver cancer cells by mediating Mcl-1 expression.

GTSF1 gene may serve as a novel potential diagnostic biomarker for liver cancer.

The gametocyte-specific factor 1 (GTSF1) gene participates in DNA methylation and retrotransposon activation in germ cells, particularly during cell proliferation. The present study aimed to assess the level of GTSF1 gene expression in liver cancer tumor tissues, and its role in human hepatoma cell lines in vitro and in a nude mouse model in vivo. GTSF1 gene expression was detected in liver cancer tumor tissues, compared with in healthy controls, via reverse transcription quantitative polymerase chain reaction. An adeno-associated virus vector was used to study tumor stem cell proliferation in vivo. A plasmid expressing GTSF1 was constructed and transfected into various human hepatoma cell lines, in order to analyze the cellular proliferation and apoptosis of liver cancer cells using small interfering (si)RNAs in vitro. In the present study, GTSF1 gene expression was detected in 18/24 (75.0%) liver cancer tumor tissues from patients with hepatocellular carcinoma (HCC), and elevated GTSF1 expression was identified in the tissue of one of 32 healthy control samples (3.13%; P<0.05). Notably, the GTSF1 gene was expressed at a higher frequency in AFP-positive HCC samples (14/16, 87.50%) compared with in AFP-negative HCC samples (4/8, 50.0%; P=0.129). In addition, there was no statistical significance between GTSF1 expression in non-HBV-infected (71.42%) and HBV-infected HCC specimens (76.47%), as determined by a χ2 test (P=0.921). It was demonstrated that GTSF1 significantly increased the tumorigenicity of Ad-shNC-transfected (GTSF1-positive) HepG2 cells in the nude mouse xenograft model, whereas the sizes and weights of the tumors in the GTSF1-negative group were dercreased in comparison with the GTSF1-positive group (P<0.05). Reduced levels of GTSF1 mRNA, along with fewer and smaller colonies, were identified in two groups of human liver cancer cells treated with with GTSF1-targeting siRNA, when compared with cells without GTSF1 mRNA interference (P<0.05). In summary, the present study elucidated the GTSF1 mRNA expression pattern in liver cancer, and investigated the potential role of GTSF1 in tumorigenesis. The data suggest an important role for the GTSF1 gene in the molecular etiology of hepatocarcinogenesis, and indicate a potential application of GTSF1 mRNA expression in liver cancer diagnosis and therapy.

The suppressive effects of Britannin (Bri) on human liver cancer through inducing apoptosis and autophagy via AMPK activation regulated by ROS

Britannin (Bri), isolated from Inula aucheriana, is a sesquiterpene lactone (SL), a class of secondary metabolites. Previous studies have suggested the anti-cancer potential of Bri; however, the molecular mechanism remains elusive. The present study investigated the effects of Bri on liver cancer progression. Our findings indicated that Bri significantly suppressed the growth of liver cancer cell lines. Mechanistic researches revealed that Bri induced apoptosis through the extrinsic and intrinsic apoptotic pathways, as evidenced by the increase of Caspase-8, -9 and -3 cleavages. In addition, Bri-triggered autophagy in liver cancer cells, supported by the up-regulation of light chain 3 (LC3) II, p62, autophagy-related 5 (ATG5) and Beclin 1, as well as the occurrence of autophagic vacuoles. Importantly, Bri increased AMPK activation, while decreased the activity of its down-streaming signal, mTOR. Of note, suppression of AMP-activated protein kinase (AMPK) activation using its inhibitor, Compound C, could inhibit both apoptosis and autophagy induced by Bri. Furthermore, Bri was found to induce reactive oxygen species (ROS) generation in hepatic cancer cells. Notably, reducing ROS production by its scavenger, N-acetyl cysteine (NAC), could down-regulate p-AMPK levels, while up-regulate the phosphorylated mechanistic target of rapamycin (p-mTOR) expressions, accompanied with the restored cell viability, as well as the reduced apoptosis and autophagy in Bri-treated liver cancer cells. Finally, Bri inhibited the tumor growth in vivo without side effects. In conclusion, our study illustrated that Bri could induce apoptosis and autophagy by activating AMPK regulated by ROS in liver cancer cells, supplying molecular bases for developing Bri into an effective candidate against liver cancer.

Methylation mediated Gadd45\u03b2 enhanced the chemosensitivity of hepatocellular carcinoma by inhibiting the stemness of liver cancer cells

BackgroundDefects of the growth arrest DNA damage-inducible gene 45β (Gadd45β) play an important role in the progression of tumor and confer resistance to chemotherapy. However, the role of Gadd45β in the apoptosis of hepatocellular carcinoma is still not clear. Purpose of this study was to explore the effect of Gadd45β on the apoptosis of liver cancer cells, and the possible mechanism was examined.ResultIn this study, we first confirmed the decreased expression of Gadd45β in human liver cancer tissues and human liver cancer cell lines, when compared to the peri-tumor liver tissue and normal liver cells. And, it was found that Gadd45β could inhibit the stemness of liver cancer cells, enhancing the apoptosis of cancer cells induced by chemotherapy. Furthermore, the results showed that HCC tissues and cell lines showed a higher methylation status in Gadd45β promoter than that in peri-tumor tissues and normal liver cells. Methylation was then reversed by pretreatment of SMMC-7721 and Hep-3B with 5-azacytidine which is the DNA methyltransferase inhibitor. And the 5-azacytidine decreased the stemness of SMMC-7721 and Hep-3B, enhanced the sensitivity of SMMC-7721 and Hep-3B to cisplatin.ConclusionsMethylation mediated Gadd45β expression inhibited the stemness of liver cancer cells, promoting the chemotherapy-induced apoptosis. Thus Gadd45β may be the potential target for enhancing the chemosensitivity of human hepatocellular carcinoma.

Ag-doping regulates the cytotoxicity of TiO2 nanoparticles via oxidative stress in human cancer cells

We investigated the anticancer potential of Ag-doped (0.5–5%) anatase TiO2 NPs. Characterization study showed that dopant Ag was well-distributed on the surface of host TiO2 NPs. Size (15 nm to 9 nm) and band gap energy (3.32 eV to 3.15 eV) of TiO2 NPs were decreases with increasing the concentration of Ag dopant. Biological studies demonstrated that Ag-doped TiO2 NP-induced cytotoxicity and apoptosis in human liver cancer (HepG2) cells. The toxic intensity of TiO2 NPs was increases with increasing the amount of Ag-doping. The Ag-doped TiO2 NPs further found to provoke reactive oxygen species (ROS) generation and antioxidants depletion. Toxicity induced by Ag-doped TiO2 NPs in HepG2 cells was efficiently abrogated by antioxidant N-acetyl-cysteine (ROS scavenger). We also found that Ag-doped TiO2 NPs induced cytotoxicity and oxidative stress in human lung (A549) and breast (MCF-7) cancer cells. Interestingly, Ag-doped TiO2 NPs did not cause much toxicity to normal cells such as primary rat hepatocytes and human lung fibroblasts. Overall, we found that Ag-doped TiO2 NPs have potential to selectively kill cancer cells while sparing normal cells. This study warranted further research on anticancer potential of Ag-doped TiO2 NPs in various types of cancer cells and in vivo models.

Effects of C heavy ion beam irradiation on the p53 signaling pathway in HepG2 liver cancer cells

The heavy ion beam is considered to be the ideal source for radiotherapy. The p53 tumor suppressor gene senses DNA damage and transducts intracellular apoptosis signals. Previous reports showed that the heavy ion beam can trigger complex forms of damage to cellular DNA, leading to cell cycle arrest and apoptosis of HepG2 human liver cancer cells; however, the mechanisms remains unclear fully. In order to explore whether the intrinsic or extrinsic pathway participates this process, HepG2 cells were treated with 12C6+ HIB irradiation at doses of 0 (control), 1, 2, 4, and 6 Gy with various methods employed to understand relevant mechanisms, such as detection of apoptosis, cell cycle, and Fas expression by flow cytometry, analysis of apoptotic morphology by electron microscopy and laser scanning confocal microscopy, and screening differentially expressed genes relating to p53 signaling pathway by PCR-array assay following with any genes confirmed by western blot analysis. This study showed that 12C6+ heavy ion beam irradiation at a dose of 6 Gy leads to endogenous DNA double-strand damage, G2/M cell cycle arrest, and apoptosis of human HepG2 cells via synergistic effect of the extrinsic and intrinsic pathways. Differentially expressed genes in the p53 signaling pathway related to DNA damage repair, apoptosis, cycle regulation, metastasis, deterioration and radioresistance were also discovered. Consequently, the expressions of Fas, TP53BP2, TP53AIP1, and CASP9 were confirmed upregulated after 12C6+ HIB irradiation treatment. In conclusion, this study demonstrated the mechanisms of inhibition and apoptosis induced by 12C6+ heavy ion beam irradiation on HepG2 cancer cells is mediated by initiation of the biological function of p53 signaling pathway including extrinsic and intrinsic apoptosis pathway.

Pseudogene PDIA3P1 promotes cell proliferation, migration and invasion, and suppresses apoptosis in hepatocellular carcinoma by regulating the p53 pathway

Pseudogenes are a subclass of long non-coding (lnc) RNAs that arose from protein-coding genes, but have lost the ability to produce proteins. Pseudogenes play an important role in the pathogenesis of various tumors; however, the role of pseudogenes in hepatocellular carcinoma (HCC) is poorly understood. In this study, we investigated a novel pseudogene, PDIA3P1, which was upregulated in HCC tissues compared with paired normal adjacent tissues. The expression of PDIA3P1 was significantly correlated with tumor size, metastasis, TNM stage, and overall stage. Knockdown of PDIA3P1decreased proliferation, migration, and invasion of HCC cells. PDIA3P1 knockdown also promoted cell apoptosis and inhibited tumor growth in vivo. We performed a GeneChip assay to investigate the underlying mechanism of PDIA3P1 action on biological function, and our results suggested that PDIA3P1 may promote proliferation and inhibit apoptosis of liver cancer cells by inhibiting the p53 pathway. Thus, our data suggest that PDIA3P1 acts as an oncogene in HCC and could be a potential prognostic marker and therapeutic target for HCC.