Study of apoptosis in human liver cancers

Research progress on chemical components and pharmacological action of Solanum lyratum Thunb

OBJECTIVES

Solanum lyratum Thunb (SLT) is a perennial plant of the Solanaceae family, and is extensively used in the clinical practice of traditional Chinese medicine. Malaria, oedema, gonorrhoea, cancer, wind and fever, jaundiced hepatitis, cholecystitis and rheumatoid arthritis are among the diseases that it is used to treat. To offer a foundation for further development and usage of SLT, the pieces of literature about the chemical composition and pharmacological action of SLT were reviewed and analysed.

KEY FINDINGS

The chemical constituents of SLT mainly included steroids, alkaloids, flavonoids, terpenoids, anthraquinones, phenylpropanoids and others. Pharmacological action mainly contains anti-tumour, antibacterial, anti-inflammatory, anti-oxidation and other pharmacological actions, among them, the anti-tumour effect is particularly outstanding.

SUMMARY

At present, studies on the pharmacological effects of SLT mainly focus on alkaloids and steroidal saponins. In the follow-up studies, studies on the pharmacological activities of other chemical components in SLT, such as flavonoids and terpenoids, should be strengthened. It has the potential to pave the way for more research and development of novel SLT medicines.

A Computational Approach to Identify Novel Potential Precursor miRNAs and their Targets from Hepatocellular Carcinoma Cells

Background:

Recent advances in next-generation sequencing technology allow highthroughput RNA-Sequencing to be widely applied in studying coding and non-coding RNA profiling in cells. RNA-Seq data usually contains functional transcriptomic and other small and larger non-coding (nc) RNA sequences. </P><P> Objective: MicroRNAs (miRNAs), a small nc-RNA act as epigenetic markers and the expression of their target genes and pathways that regulate Hepatocellular Carcinoma (HCC), a primary malignancy of the liver. The unreported potential novel miRNAs targeting HCC pathways can be identified from the sequenced data.

Methods:

In this study, we performed a computational identification of novel putative miRNAs and their targets from publicly available high-throughput sequencing Fastq data of human HCC cells HepG2, NorHep and SKHep1, retrieved from NCBI-SRA.

Results:

Totally, 572 unique known precursor miRNAs and 1062 unique novel miRNAs were identified from HepG2, Nor and SKHep1 HCC cell lines. Interestingly, 140 novel miRNAs were predicted to be extensively involved in targeting genes of HCC related pathways such as apoptosis, cell signaling, cell division, cell-cycle arrest, GPCR, MAPK cascade, TOR signaling, TNFSF11 signaling and liver development.

Conclusion:

The predicted novel miRNAs reported in the paper might have a vital role in regulating the molecular mechanism of HCC and thus, further studies on these miRNAs will provide significant clues for researchers into the complex biological process of liver cancer.

Induction of cell cycle arrest and apoptosis in human osteosarcoma U-2 OS cells by Solanum lyratum extracts

This research focused on a Chinese herb medicine, Solanum lyratum Thunb (Solanaceae) by ethanol extracts (SLE) for investigating the molecular anticancer mechanism in vitro for exploring the means of cell death through the effects on mitochondrial function. We found that SLE induced cytotoxic effects in human osteosacroma U-2 OS cells, and these effects include cell morphological changes, a decrease of the percentage of viable cells and induction of apoptosis. The results suggest that cell death induced by SLE is closely related to apoptosis based on the observations of DAPI staining and sub-G1 phase in U-2 OS cells. Flow cytometric assays also showed that SLE promoted the production of reactive oxygen species and nitric oxide but decreased the levels of mitochondrial membrane potential and promoted the activations of caspase-8 and -9 in U-2 OS cells. SLE inhibited the level of Bcl-2 but promoted the Bax level, and both proteins led to the release of cytochrome c from mitochondria to cytosol and activation of caspase-9 and -3, resulting in the apoptotic death which is mediated through the mitochondrial pathway. Taken together, SLE was demonstrated to be effective in killing U-2 OS osteosacroma cells via the ROS-promoted and mitochondria- and caspase-dependent apoptotic pathways.

Solanum lyratum Extracts Induce Extrinsic and Intrinsic Pathways of Apoptosis in WEHI-3 Murine Leukemia Cells and Inhibit Allograft Tumor

We investigated the molecular mechanisms of cell cycle arrest and apoptotic death induced by Solanum lyratum extracts (SLE) or diosgenin in WEHI-3 murine leukemia cells in vitro and antitumor activity in vivo. Diosgenin is one of the components of SLE. Our study showed that SLE and diosgenin decreased the viable WEHI-3 cells and induced G₀/G₁ phase arrest and apoptosis in concentration- or time-dependent manners. Both reagents increased the levels of ROS production and decreased the mitochondrial membrane potential (ΔΨ_m). SLE- and diosgenin-triggered apoptosis is mediated through modulating the extrinsic and intrinsic signaling pathways. Intriguingly, the p53 inhibitor (pifithrin-α), anti-Fas ligand (FasL) mAb, and specific inhibitors of caspase-8 (z-IETD-fmk), caspase-9 (z-LEHD-fmk), and caspase-3 (z-DEVD-fmk) blocked SLE- and diosgenin-reduced cell viability of WEHI-3 cells. The in vivo study demonstrated that SLE has marked antitumor efficacy against tumors in the WEHI-3 cell allograft model. In conclusion, SLE- and diosgenin-induced G₀/G₁ phase arrest and triggered extrinsic and intrinsic apoptotic pathways via p53 activation in WEHI-3 cells. SLE also exhibited antitumor activity in vivo. Our findings showed that SLE may be potentially efficacious in the treatment of leukemia in the future.

Solannm lyratum extract affected immune response in normal and leukemia murine animal in vivo

Solanum lyratum Thunberg (Solanaceae) has been used as a folk medicine for treating liver, lung and esophagus in the Chinese population. Our previous studies have shown that the crude extract of S. lyratum Thunberg (SLE) induced apoptosis in colo 205 human colon adenocarcinoma cells; however, there is no report to show SLE affect immune responses in vivo. In this study, the in vivo effects of SLE on leukemia WEHI-3 cells and immune responses such as phagocytosis and natural killer (NK) cell activity in normal and leukemia mice were investigated. The SLE treatment decreases surface markers of CD3 and Mac-3 in normal and leukemia mice but promoted the cell markers of CD19 and CD11b in normal mice and CD11b in leukemia mice indicating that the precursors of T cells was inhibited and B cells and macrophage were promoted. The SLE treatment promoted the activity of macrophage phagocytosis in the peripheral blood mononuclear cells (PBMC) and peritoneal cells from normal and leukemia mice. The results also showed that NK cells from the normal and leukemia mice after treatment with SLE can kill the YAC-1 target cells. Therefore, the SLE treatment increased macrophage and NK cell activities. These consistent results indicate SLE could be a potent immune responses agent.

Crude extracts of Solanum lyratum protect endothelial cells against oxidized low-density lipoprotein-induced injury by direct antioxidant action

BACKGROUND

Oxidized low-density lipoprotein (oxLDL) is a proatherogenic molecule that accumulates in the vascular wall and contributes to the pathogenesis of vascular dysfunction early in the development of atherosclerosis. The whole plant of Solanum lyratum is a traditional Chinese medicine that has been used for centuries to treat cancer, tumors, and herpes. However, the cellular and molecular mechanisms of its antioxidant effects are still largely unknown. This study tested the hypothesis that Solanum lyratum Thunberg extract (SLE) could block oxLDL-induced endothelial dysfunction in cultured human umbilical vein endothelial cells (HUVECs). Possible mechanisms were explored.

METHODS

Antioxidative activities of SLE were assayed by measuring the scavenging of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical and the inhibition of copper-mediated or cell-mediated LDL oxidation. Production of reactive oxygen species (ROS) and the expression of adhesion molecules were evaluated in HUVECs after exposure to oxLDL and treatment with SLE. Several apoptotic signaling pathways were investigated.

RESULTS

SLE scavenged DPPH and also delayed the kinetics of LDL oxidation in a dose-dependent manner. SLE attenuated the level of oxLDL-induced ROS generation, diminished the expression of endothelial NO synthase (eNOS), and enhanced the expression of adhesion molecules (vascular cellular adhesion molecule-1, E-selectin, and monocyte chemotactic protein-1) and the adherence of monocytic THP-1 cells to HUVECs. OxLDL increased the concentration of intracellular calcium, disturbed the balance of the Bcl-2 protein family, destabilized the mitochondrial membrane potential, increased the amount of cytochrome c released into the cytosol, and increased the activation of caspase 3. These detrimental effects were ameliorated dose-dependently by SLE (P < .05).

CONCLUSION

Crude extracts of Solanum lyratum protect against oxLDL-induced injury in endothelial cells by direct antioxidant action.

CLINICAL RELEVANCE

Atherosclerosis is a chronic inflammatory disease characterized by lipid-laden lesions within arterialblood vessel walls. Inhibiting the oxidation of low-density lipoprotein may be an effective way to prevent or delay theprogression of atherosclerosis. This study underscores the potential clinical benefits and application of Solanum lyratumextract in controlling oxidized low-density lipoprotein-associated vascular injury and cardiovascular disease.

Ethnobotanical study of medicinal plants used by Hakka in Guangdong, China

ETHNOPHARMACOLOGICAL RELEVANCE

An ethnobotanical survey was conducted to collect information on the use of medicinal plants by the Hakka living in Guangdong.

AIM OF THE STUDY

This investigation was to document valuable knowledge represented by Hakka herbal medicine.

MATERIALS AND METHODS

Information was obtained from semi-structured interviews, personal conversations with practitioners, direct observations, and by reviewing studies of Hakka and Cantonese reported in the literature.

RESULTS

Our data covered 94 species belonging to 77 genera in 40 families. We found that most species used for medical purposes were for hepatitis (14 species) and skin diseases (12 species). These disorders are prevalent and are primarily treated with medicinal plants. For treatment, the plants were mainly used as teas (Luica, Bugingca and Lopêdca), medicinal baths and soups. The Hakka and non-Hakka people living in Guangdong use different medicinal plants and, in some cases, use the same medicinal plants differently.

CONCLUSIONS

The fast disappearance of traditional culture and natural resources due to urbanization and industrialization suggests that unrecorded information may be lost forever. Thus, there is an urgent need both to record this valuable Hakka medicinal knowledge and to encourage its transfer to the next generation.

Effects of Terminalia arjuna bark extract on apoptosis of human hepatoma cell line HepG2

AIM: To investigate the effects of Terminalia arjuna (T. arjuna) extract on human hepatoma cell line (HepG2) and its possible role in induction of apoptosis.

METHODS: Human hepatoma cells were treated with different concentrations of ethanolic extract of T. arjuna and its cytotoxicity effect was measured by trypan blue exclusion method and lactate dehydrogenase leakage assay. Apoptosis was analyzed by light and fluorescence microscopic methods, and DNA fragmentation. The mechanism of apoptosis was studied with expression of p53 and caspase-3 proteins. Glutathione (GSH) content was also measured in HepG2 cells after T. arjuna treatment.

RESULTS: T. arjuna inhibited the proliferation of HepG2 cells in a concentration-dependent manner. Apoptotic morphology was observed in HepG2 cells treated with T. arjuna at the concentrations of 60 and 100 mg/L. DNA fragmentation, accumulation of p53 and cleavage of procaspase-3 protein were observed in HepG2 cells after the treatment with T. arjuna. The depletion of GSH was observed in HepG2 cells treated with T. arjuna.

CONCLUSION: T. arjuna induced cytotoxicity in HepG2 cells in vitro. Apoptosis of HepG2 cells may be due to the DNA damage and expression of apoptotic proteins. Depletion of GSH may be involved in the induction of apoptosis of HepG2 cells.

The inhibitory effect of a herbal formula comprising ginseng and carthamus tinctorius on breast cancer

A compound (Zhu-xiang) from herbal extracts containing ginseng and carthamus tinctorius was used to treat the MDA-MB-231 breast cancer cell and normal human mammary gland cell lines. The inhibition of cell proliferation by Zhu-xiang, epirubicin, 5-fluorouracil and cyclophosphamide was determined by WST-1 assays. The apoptotic effect was studied by flow cytometry analysis of DNA strand breaks and ApopTag Peroxidase In Situ Apoptosis kit by the TUNEL assay. The proliferation index as well as cell cycle progression were also evaluated by flow cytometry using Ki-67 and propidium iodide respectively as markers. The Zhu-xiang showed significantly inhibition in cell proliferation and the inhibition was dose dependent. The inhibitory effect of Zhu-xiang was significantly greater than commonly used cytotoxic drugs. The inhibitory effect is a result of the induction of apoptosis, which is concentration- and time-dependent. DNA histograms indicate that the compound causes accumulation of cells mainly in the S phase. The viability of cells in breast solid tumours was measured by ATP bioluminescence assay to determine the drug-induced cytotoxicity of Zhu-xiang. The three different concentrations of Zhu-xiang all exhibited the ability to inhibit proliferation in solid tumour. Zhu-xiang could be a useful anti-cancer compound against breast cancer.

Inhibitory effects of celecoxib on proliferation of human liver and gastric carcinoma cells in vitro

AIM: To study the inhibitory effects of celecoxib on proliferation of human hepatoma SMMC-7721 cells and gastric cancer SGC-7901 cells in vitro.

METHODS: The two carcinoma cells were cultured with celecoxib at various concentrations(0, 20, 40, 80, 160 and 320 mmol/L). Growth suppression was detected with MTT colorimetric assay, cell apoptotic alterations were evaluated by transmission electron microscopy(TEM), and quantity of Cox-2 was evaluated by cytochemical staining.

RESULTS: The inhibition of proliferation on two carcinoma cells was observed(49.1% and 42.9% by 320 mmol/L celecoxib). The inhibitory effect was dose-dependent. Apoptotic cells were observed under transmission electron microscope. The different quantities of Cox-2 protein in cells were observed by cytochemical staining.

CONCLUSION: Celecoxib inhibits proliferation, induces apoptosis of human two carcinoma cells in vitro, and the effects have close relation to the quantities of Cox-2 protein in cells.

Establishment of apoptotic model induced by hydroxyapatite nanoparticles in human hepatoma cell line BEL-7402

AIM

To establish an apoptotic model induced by hydroxyapatite (HAP) nanoparticles in human hepatoma cell line in vitro in order to explore the mechanism of nanoparticles-induced apoptosis.

METHODS

The selected human hepatoma cell line BEL-7402 was treated with HAP nanoparticles at different concentrations and for various durations of time. Growth suppression was evaluated by MTT method. Apoptosis-related alterations in morphology and biochemistry were ascertained under cytochemical staining (Hoechst 33 258), transmission electron microscopy (TEM), and DNA agarose gel electrophoresis. Flow cytometry (FCM) was used to investigate the apoptotic rate.

RESULTS

HAP nanoparticles inhibited the growth of hepatoma cells in a dose and time-dependent manner. After BEL-7402 cells were treated with 50-200 mg/L HAP nanoparticles for 48 h, apoptosis with nuclear chromatin condensation and fragmentation as well as cell shrinkage were observed using fluorescent staining and TEM. DNA ladder could be demonstrated on DNA electrophoresis. By FCM analysis, the apoptotic rates at concentrations of 0 mg/L, 50 mg/L,75 mg/L, 100 mg/L, 150 mg/L, 200 mg/L were 2.2%, 20.3%, 25.3%, 29.8%, 45.1% and 53.1%, respectively. Cell apoptosis began approximately at 12h after administration of 50 mg/L and peaked at 48 h following treatment. The rates at 12, 24, 36, and 48 h were 2.7%, 3.5%, 6.3%, and 21.4%, respectively.

CONCLUSION

HAP nanoparticles not only inhibit proliferation but also induce apoptosis of human hepatoma cell line BEL-7402 in vitro. The successful establishment of this model will help further explore the molecular mechanism of hepatoma cells apoptosis.

Effects of hydroxyapatite nanoparticles on proliferation and apoptosis of human hepatoma BEL-7402 cells

AIM: To study the effect of hydroxyapatite (HAP) nanoparticles on human hepatoma cell line BEL-7402 in vitro.

METHODS: The human hepatoma cell line BEL-7402 was cultured and treated with HAP nanoparticles at various concentrations. Growth suppression was detected with MTT colorimetric assay, cell apoptotic alterations were evaluated by cytochemical staining (Hoechst 33258), transmission electron microscopy (TEM), and flow cytometry (FCM).

RESULTS: HAP nanoparticles inhibited the growth of hepatoma cells in a dose-dependent manner, with IC₅₀ values of 29.30 mg/L. Treated with 50-200 mg/L HAP nanoparticles for 48 h, BEL-7402 cells apoptosis with nuclear chromatin condensation and fragmentation as well as cell shrinkage and the formation of apoptotic bodies were observed under cytochemical staining and transmission electron microscopy. FCM analysis showed hypodiploid peaks on histogram, the apoptotic rates at the concentrations of 50, 75, 100, 150 and 200 mg/L of HAP nanoparticles were 20.35 ± 2.23%, 25.35 ± 1.92%, 29.34 ± 4.61%, 44.92 ± 3.78% and 53.64 ± 3.49%, respectively, which were all significantly higher than that of control group 2.23 ± 0.14%. There was a significant correlation between HAP nanoparticle concentration and apoptotic rate (r = 0.994, P < 0.01).

CONCLUSION: HAP nanoparticles not only inhibit proliferation but also induce apoptosis of human hepatoma cell line BEL-7402 in vitro.

In situ quantitative study of BAG-1 and BAD in extrahepatic cholangiocarcinoma

AIM

To detect the expression of apoptosis related proteins BAG-1 and BAD and to investigate their functions of apoptosis modulation and relations to tumor differentiation in extrahepatic cholangiocarcinoma.

METHODS

Quantitative in situ methods of DAKO EnvisionTM Systems immunohistochemistry in combination with computer-assisted image analysis and apoptotic cells counting were used to observe the expression levels of BAG-1 and BAD and the apoptosis indexes in 42 cases of extrahepatic cholangiocarcinoma.

RESULTS

The expression levels of BAG-1 and BAD were measured with average absorbance (A) derived from the quantitative image analysis. Among 24, 13 and 5 cases of well, moderately and poorly differentiated extrahepatic cholangiocarcinomas, the average A of BAG-1 was respectively 0.068±0.037, 0.112±0.057 and 0.152±0.062, of BAD was respectively 0.079±0.053, 0.138±0.058 and 0.165±0.061, and the apoptotic indexes examined in the hematoxylin-and-eosin-stained specimens were respectively 1.1±0.5, 1.7±0.3 and 3.5±1.3. The expression levels of BAG-1 and BAD and the apoptotic indexes were increased obviously from well, moderately to poorly differentiated extrahepatic cholangiocarcinoma (P<0.05). The expression level of BAD was correlated to the apoptotic indexes (P<0.01).

CONCLUSION

Expressions of BAG-1 and BAD and apoptosis indexes were all associated with differentiation of extrahepatic cholangiocarcinoma. BAG-1 and BAD may take part in the apoptosis modulation of the tumor.

Expression of survivin in human gastric carcinoma and gastric carcinoma model of rats

AIM: To study the expression of survivin, an inhibitor of apoptosis protein, in human gastric carcinomas and gastric carcinoma models of rats.

METHODS: With the method of immunohistochemical staining, we studied the expression of survivin in 20 cases of chronic gastritis and 56 cases of gastric carcinomas. We used N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and high dose sodium-chloride diet to induce rat gastric carcinomas. Survivin expression was studied in glandular stomachs of normal rats, adenocarcinomas and tissues adjacent to the tumor, as well as in rats during the induction period.

RESULTS: Survivin was expressed in 27 of 56 (48.2%) cases of human gastric carcinoma tissues and 1 of 20 (5%) cases of chronic gastritis. It was found that the expression of survivin had no relation with the elements of age, tumor depth, tumor size, and disease stage, but was significantly related to histological type. The positive rate of survivin expression in cases of intestinal type was significantly higher than that in cases of diffuse type (P < 0.05). In animal experiments, survivin expression in glandular stomachs of normal rats, of rats in middle induction period, in adenocarcinomas and tissues adjacent to tumor were 0, 40.0%, 78.3% and 38.9%, respectively. Compared with the survivin expression in normal rats, the differences were significant.

CONCLUSION: These data imply that survivin plays an important role in the onset of gastric carcinoma and that high survivin expression is an early event of gastric carcinoma.

Expression of survivin protein in hepatocellular carcinoma tissues and its relationship with clinical pathological features and prognosis

AIM

To investigate the expression of survivin protein in human hepatocellular carcinoma (HCC) and its relationship with clinical features and prognosis of patients with HCC.

METHODS

The expression of survivin protein and the proliferation of tumor cells marked by PCNA in 48 cases of HCC were assessed by immunohistochemical method. TUNEL method was used to detect apoptosis.

RESULTS

The survivin protein was expressed in 31 of 48 cases of HCC (64.6%). Expression of survivin protein was significantly higher in those of Edmondson grade Ⅲ-Ⅳ than in those of grade Ⅰ-Ⅱ (88.0% vs 39.1%, P = 0.013). The ratio of proliferative index to apoptotic index was significantly higher in HCC with positive survivin expression than that with negative survivin expression (1.8 vs 1.1, P = 0.045). The survival rate of three years of patients with positive survivin expression was significantly lower than that of patients with negative survivin expression (70.6% vs 35.5%, P = 0.011).

CONCLUSION

The expression of survivin may play an important role in breaking the balance of proliferation and apoptosis of HCC cells and is closely associated with prognosis of patients with HCC.