FADD and TRADD expression and apoptosis in primary hepatocellular carcinoma

Achillea fragrantissima (Forssk.) Sch.Bip instigates the ROS/FADD/c-PARP expression that triggers apoptosis in breast cancer cell (MCF-7)

Achillea fragrantissima is a shrub plant that belongs to the Asteraceae family in Arabia and Egypt. It is used as folk medicine and is a good source of phenolic acids, flavonoids, and some active compounds. To investigate the anti-cancer effect of A.fragrantissima on breast cancer MCF-7 cells and find the critical mechanism involved in apoptosis. The toxicity and pharmacokinetic studies of ethanolic extract of A.fragrantissima was examined for anti-breast cancer properties. In turn, cytotoxicity and cell viability were achieved by the MTT method. Furthermore, the trypan blue exclusion and microscopy examination proved the presence of apoptotic cells. Again, fluorescent staining such as AO/EtBr, DCFH-DA, Rho-123, and Hoechst-33342 reveals the cellular cytoplasmic disciplines upon A. fragrantissima effect. Moreover, cellular functioning tests like wound healing, colony formation, and Transwell invasion assay were demonstrated. In addition, the qRT-PCR technique authenticates the A. fragrantissima -induced apoptotic network genes (Caspase-3, Caspase-8, Caspase-9, Cytochrome c, BCL-2, BID, BAX, PARP, PTEN, PI3K, and Akt) expression were evaluated. Mainly, the Immunoblot technique proved the expressed level of apoptotic proteins such as cleaved PARP, CYCS, and FADD. This study confirmed that the A. fragrantissima exerts cytotoxicity at 20 μg/mL for 24 hrs in MCF-7 cells. Also, decreases cellular viability, producing apoptotic cells and damaged cellular surfaces with dead matter. Consequently, it creates ROS species accumulation, loss of mitochondrial membrane potential, and fragmentation of DNA in MCF-7 cells. Furthermore, it arrests cell migration, induces colony-forming ability loss, and suppresses cell invasion. In addition, A. fragrantissima significantly upregulates genes such as caspase-3, 9, cytochrome c, BID, BAX, and PTEN while downregulating the Pi3K/ Akt signaling. Nonetheless, A.fragrantissima induced cleaved PARP, CYCS, and FADD proteins in MCF-7 cells to avail apoptosis.

Regulation of apoptosis by ubiquitination in liver cancer

Apoptosis is a programmed cell death process critical to cell development and tissue homeostasis in multicellular organisms. Defective apoptosis is a crucial step in the malignant transformation of cells, including hepatocellular carcinoma (HCC), where the apoptosis rate is higher than in normal liver tissues. Ubiquitination, a post-translational modification process, plays a precise role in regulating the formation and function of different death-signaling complexes, including those involved in apoptosis. Aberrant expression of E3 ubiquitin ligases (E3s) in liver cancer (LC), such as cellular inhibitors of apoptosis proteins (cIAPs), X chromosome-linked IAP (XIAP), and linear ubiquitin chain assembly complex (LUBAC), can contribute to HCC development by promoting cell survival and inhibiting apoptosis. Therefore, the review introduces the main apoptosis pathways and the regulation of proteins in these pathways by E3s and deubiquitinating enzymes (DUBs). It summarizes the abnormal expression of these regulators in HCC and their effects on cancer inhibition or promotion. Understanding the role of ubiquitination in apoptosis and LC can provide insights into potential targets for therapeutic intervention.

Comparative single-cell profiling reveals distinct cardiac resident macrophages essential for zebrafish heart regeneration

Zebrafish exhibit a robust ability to regenerate their hearts following injury, and the immune system plays a key role in this process. We previously showed that delaying macrophage recruitment by clodronate liposome (-1d_CL, macrophage-delayed model) impairs neutrophil resolution and heart regeneration, even when the infiltrating macrophage number was restored within the first week post injury (Lai et al., 2017). It is thus intriguing to learn the regenerative macrophage property by comparing these late macrophages vs. control macrophages during cardiac repair. Here, we further investigate the mechanistic insights of heart regeneration by comparing the non-regenerative macrophage-delayed model with regenerative controls. Temporal RNAseq analyses revealed that -1d_CL treatment led to disrupted inflammatory resolution, reactive oxygen species homeostasis, and energy metabolism during cardiac repair. Comparative single-cell RNAseq profiling of inflammatory cells from regenerative vs. non-regenerative hearts further identified heterogeneous macrophages and neutrophils, showing alternative activation and cellular crosstalk leading to neutrophil retention and chronic inflammation. Among macrophages, two residential subpopulations (hbaa+ Mac and timp4.3+ Mac 3) were enriched only in regenerative hearts and barely recovered after +1d_CL treatment. To deplete the resident macrophage without delaying the circulating macrophage recruitment, we established the resident macrophage-deficient model by administrating CL earlier at 8 d (-8d_CL) before cryoinjury. Strikingly, resident macrophage-deficient zebrafish still exhibited defects in revascularization, cardiomyocyte survival, debris clearance, and extracellular matrix remodeling/scar resolution without functional compensation from the circulating/monocyte-derived macrophages. Our results characterized the diverse function and interaction between inflammatory cells and identified unique resident macrophages prerequisite for zebrafish heart regeneration.

Health benefits of flaxseed and its peptides (linusorbs)

Flaxseed (Linum usitatissimum L.) has been associated with numerous health benefits. The flax plant synthesizes an array of biologically active compounds including peptides or linusorbs (LOs, a.k.a., cyclolinopeptides), lignans, soluble dietary fiber and omega-3 fatty acids. The LOs arise from post-translational modification of four or more ribosome-derived precursors. These compounds exhibit an array of biological activities, including suppression of T-cell proliferation, excessive inflammation, and osteoclast replication as well as induction of apoptosis in some cancer cell lines. The mechanisms of LO action are only now being elucidated but these compounds might interact with other active compounds in flaxseed and contribute to biological activity attributed to other flax compounds. This review focuses on both the biological interaction of LOs with proteins and other molecules and comprehensive knowledge of LO pharmacological and biological properties. The physicochemical and nutraceutical properties of LOs, as well as the biological effects of certain LOs, and their underlying mechanisms of action, are reviewed. Finally, strategies for producing LOs by either peptide synthesis or recombinant organisms are presented. This review will be the first to describe LOs as a versatile scaffold for the action of compounds to deliver physiochemically/biologically active molecules for developing novel nutraceuticals and pharmaceuticals.

Activation of death receptor, DR5 and mitochondria-mediated apoptosis by a 3,4,5-trimethoxybenzyloxy derivative in wild-type and p53 mutant colorectal cancer cell lines

The rationale of designing compounds containing a (3,4,5-trimethoxybenzyloxy) phenyl moiety is largely due to its potential antioxidant and cytotoxic activities. A previous study focused on its antioxidant mechanism, whereas in this study, we investigated the cytotoxicity of a series of 28 analogues and the mechanism of apoptosis of the most cytotoxic compound against wild-type (HCT-116) and p53 mutant (HT-29) colorectal cancer cell lines. The series of analogues comprise of different families, namely hydrazone, oxadiazole, thiosemicarbazides and triazoles. In the initial cytotoxicity screening, N-(3,4,5-trimethoxybenzylidene)-4-(3,4,5-trimethoxybenzyloxy) benzohydrazide, henceforth known as, P5H, was found to be most cytotoxic against human colorectal cancer cell lines (IC₅₀ for HCT-116 = 11.79 μM and HT-29 = 18.52 μM). Additionally, P5H was found to have some degree of selectivity towards cancer cells compared to normal human colon cells (CCD-112 CoN). Subsequent investigation had brought insight on P5H ability to induce apoptosis in both HCT-116 and HT-29 cell lines. Cell cycle analysis showed both cell lines were arrested at the G2/M phase upon treatment. Our study concluded that P5H induced the death receptor, DR5 in HCT-116 and mitochondria-mediated apoptosis pathway in HT-29. Therefore, P5H may be a promising candidate as a chemotherapy agent against colon cancer. Graphical abstract The apoptotic pathways induced in HT-29 and HCT-116 cells upon P5H treatment.

New Drugs from the Sea: Pro-Apoptotic Activity of Sponges and Algae Derived Compounds

Natural compounds derived from marine organisms exhibit a wide variety of biological activities. Over the last decades, a great interest has been focused on the anti-tumour role of sponges and algae that constitute the major source of these bioactive metabolites. A substantial number of chemically different structures from different species have demonstrated inhibition of tumour growth and progression by inducing apoptosis in several types of human cancer. The molecular mechanisms by which marine natural products activate apoptosis mainly include (1) a dysregulation of the mitochondrial pathway; (2) the activation of caspases; and/or (3) increase of death signals through transmembrane death receptors. This great variety of mechanisms of action may help to overcome the multitude of resistances exhibited by different tumour specimens. Therefore, products from marine organisms and their synthetic derivates might represent promising sources for new anticancer drugs, both as single agents or as co-adjuvants with other chemotherapeutics. This review will focus on some selected bioactive molecules from sponges and algae with pro-apoptotic potential in tumour cells.

Diethylnitrosamine Increases Proliferation in Early Stages of Hepatic Carcinogenesis in Insulin-Treated Type 1 Diabetic Mice

Diethylnitrosamine (DEN) induces hepatocarcinogenesis, increasing mitotic hepatocytes and leading to chronic inflammation. In addition, type 1 diabetes mellitus (T1DM) is also characterized by a proinflammatory state and by requiring insulin exogenous treatment. Given the association of diabetes, insulin treatment, and cell proliferation, our specific goal was to determine whether the liver in the diabetic state presents a greater response to DEN-induced cell cycle alteration, which is essential for the malignant transformation. Male C57BL/6 mice (four-week-old) were divided into 4 groups: C, C + DEN, T1DM, and T1DM + DEN. Mice were euthanized ten weeks after DEN injection. DEN per se produced an increase in liver lipid peroxidation levels. Besides, in T1DM + DEN, we found a greater increase in the proliferation index, in comparison with C + DEN. These results are in agreement with the increased expression observed in cell cycle progression markers: cyclin D1 and E1. In addition, a proapoptotic factor, such as activated caspase-3, evidenced a decrease in T1DM + DEN, while the Vascular Endothelial Growth Factor (VEGF) and the protooncogene p53 showed a higher increase with respect to C + DEN. Overall, the results allow us to highlight a major DEN response in T1DM, which may explain in part the greater predisposition to the development of hepatocarcinoma (HCC) during the diabetic state.

Silencing of Pokemon enhances caspase-dependent apoptosis via fas- and mitochondria-mediated pathways in hepatocellular carcinoma cells

The role of Pokemon (POK erythroid myeloid ontogenic actor), a recently identified POK transcription factor with proto-oncogenic activity, in hepatocellular carcinogenesis has only been assessed by a few studies. Our previous study revealed that Pokemon is overexpressed in hepatocellular carcinomas (HCC) and promotes HCC cell proliferation and migration via an AKT- and ERK- dependent manner. In the present study, we used the TUNEL assay and FACS analysis to demonstrate that oxaliplatin induced apoptosis was significantly increased in cells with silenced Pokemon. Western blots showed that p53 expression and phosphorylation were significantly increased in Pokemon defective cells, thereby initiating the mitochondria-mediated and death receptor-mediated apoptotic pathways. In the mitochondria-mediated pathway, expression of pro-apoptotic Bcl-2 family members (including Bad, Bid, Bim and Puma) as well as AIF was increased and decreasing the mitochondrial membrane potential resulted in cytochrome C released from mitochondrial in HepG2 si-Pokemon cells. In addition, upon oxaliplatin treatment of Pokemon-silenced cells, the FAS receptor, FADD and their downstream targets caspase-10 and caspase-8 were activated, causing increased release of caspase-8 active fragments p18 and p10. Increased activated caspase-8-mediated cleavage and activation of downstream effector caspases such as caspase-9 and caspase-3 was observed in HepG2 si-Pokemon cells as compared to control. Therefore, Pokemon might serve as an important mediator of crosstalk between intrinsic and extrinsic apoptotic pathways in HCC cells. Moreover, our findings suggest that Pokemon could be an attractive therapeutic target gene for human cancer therapy.

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.

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.

Role of inducible nitric oxide synthase expression in aberrant crypt foci-adenoma-carcinoma sequence

AIM: To investigate the expression of inducible nitric oxide synthase (iNOS) in aberrant crypt foci (ACF) -adenoma-carcinoma sequence and its relation with tumor cell apoptosis, proliferation and angiogenesis.

METHODS: The expression of iNOS, proliferating cell nuclear antigen (PCNA) and microvessel density (MVD) in different stages of colorectal cancer were studied by immunohistochemical method from 30 normal tissues, 30 nonhyperplastic ACF, 30 hyperplastic ACF, 30 dysplastic ACF, 30 adenomas and 60 carcinomas. The apoptotic cells were detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method using an Apop Tag in situ detection kit.

RESULTS: The immunoreactivity of iNOS significantly increased in the transition from hyperplastic ACF to dysplastic ACF. This transition was associated with a significant decrease in the apoptotic index (AI) (0.73 ± 0.37 vs 0.61 ± 0.35, P < 0.05) and significant increases in the PCNA labeling index (LI) (27.3 ± 2.80 vs 40.3 ± 3.11, P < 0.01) and microvessel density (MVD) (55 ± 11.5 vs 70 ± 13.2, P < 0.01). The expression of iNOS was in low levels and positively correlated with PCNA-LI (r = 0.812, P < 0.01) and MVD (r = 0.863, P < 0.01) during transition from normal mucosa to nonhyperplastic ACF and hyperplastic ACF. The expression of iNOS was in high levels and positively correlated with AI (r = 0.901, P < 0.01) after transition from hyperplastic ACF to dysplastic ACF, adenoma and carcinoma.

CONCLUSION: The results suggest that the transition from hyperplastic ACF to dysplastic ACF may be a crucial step in the ACF-adenoma-carcinoma sequence, in which iNOS plays an important role by regulating tumor cell apoptosis, proliferation and angiogenesis.

Experimental study on ultrasound-guided intratumoral injection of “Star-99” in treatment of hepatocellular carcinoma of nude mice

AIM: To investigate the anti-cancer effect and the immunological mechanism of ultrasound-guided intratumoral injection of Chinese medicine “Star-99” in hepatocellular carcinoma (HCC) of nude mice.

METHODS: Twenty-eight human hepatocellular carcinoma SMMC-7721 transplanted nude mice, 14 of hypodermically implanted and 14 of orthotopic liver transplanted, were randomly divided into three groups of which 14 mice with Star-99, and 7 with ethanol and saline respectively. Ten days after the transplantation the medicines were injected into the tumors of all the nude mice once every 5 d. After 4 injections the nude mice were killed. The diameters of three dimension of the tumors were measured by high frequency ultrasound before and after the treatment and the tumor growth indexes^* (TGI) were calculated. Radioimmunoassay was used to detect the serum levels of interleukin-2 (IL-2) and tumor necrosis factor (TNF)-alpha. The tumor tissues were sent for flow cytometry (FCM) DNA analysis. Apoptotic cells were visualized by TUNEL assay. All the experiments were carried out by double blind method.

RESULTS: The TGI of Star-99 group (0.076 ± 0.024) was markedly lower than that of the saline group (4.654 ± 1.283) (P < 0.01). It also seemed to be lower than that of the ethanol group (0.082 ± 0.028), but not significantly different (P > 0.05). Serum levels of IL-2 and TNF-α were markedly higher than those of ethanol group and saline groups (P < 0.05). The mean apoptotic index (AI: percentage of TUNEL signal positive cells) in Star-99 group (48.98% ± 5.09%) was significantly higher than that of the ethanol group (11.95% ± 2.24%) and the saline group (10.48% ± 3.85%) (P < 0.01). FCM DNA analysis showed that the appearance rate of the apoptosis peak in Srar-99 group was 92.9%, markedly higher than that of the ethanol group (14.3%) and the saline group (0.0%) (P < 0.01). Correlation (r = 0.499, P < 0.05) was found between AI and serum level of TNF-α.

CONCLUSION: Star-99 has an effect on the elevation of the serum levels of IL-2 and TNF-α. It indicates that Star-99 has the function of enhancing the cellular immunity and inducing cancer cell apoptosis. The correlation between AI and serum level of TNF-α indicates that the elevation of the serum of TNF-α induced by Star-99 may be an important factor in the promotion of the hepatic cancer cell apoptosis. Star-99 has strong effects on the inhibition and destruction of cancer cells. Its curative effect is as good as ethanol. Its major mechanisms can be as follows: (1) it increases the serum levels of IL-2 and TNF-α and triggers cellular immunity. (2) It can induce cancer cells apoptosis, the effective mechanism of the Star-99 is different from that of the ethanol. The mechanisms of triggering the immunologic function of the organism and inducing cell apoptosis are, of particular significance. This study will provide a new pathway of drug administration and an experimental basis for the treatment of HCC with Chinese herbal, and the study of Star-99 in the treatment of tumor is of profound significance with good prospects.

Relationship between Egr-1 gene expression and apoptosis in esophageal carcinoma and precancerous lesions

AIM: To study the expression of early growth response gene-1 (Egr-1 gene) and Bcl-X/_L protein and its relationship with the cell apoptosis in human esophageal carcinoma(EC) and precancerous lesions.

METHODS: In situ hybridization(ISH), immunohistochemistry (IHC) and TUNEL method were used respectively to detect Egr-1mRNA,Egr-1 protein, apoptosis related-protein Bcl-X/_L and cell apoptosis in situ from 66 cases of esophageal squamous cell carcinoma and their upper cut edge and paracancerous mucosa.

RESULTS: Egr-1 gene in situ hybridization, Bcl-X/_L immunohistochemistry positive products were located in the cytoplasm, while Egr-1 immunohistochemistry and TUNEL positive signal were located in the nuclei. The apoptosis index(AI) and the frequency of apoptosis occurrence were increased gradually from precancerous lesion to cancer (P < 0.01) and the expression of Egr-1mRNA and Egr-1 protein in dysplasia was the highest among all specimens (P < 0.01). The AI of Egr-1 positive cancer tissues was much higher than that of Egr-1 negative cancer tissues (P < 0.01), while the AI of Bcl-X/_L positive cancer tissues was much lower than that of Bcl-X/_L negative cancer tissues (P < 0.01). The AI and Egr-1 expression were not correlated with invasiveness and lymphatic metastasis in EC.

CONCLUSION: Cell apoptosis was present through esophageal carcinogenesis. The expression of Egr-1 mRNA and Egr-1 protein were high in precancerous lesion of esophagus. The AI was increased significantly in Egr-1 positive squamous cell carcinoma. Egr-1 might promote apoptotic effect. Egr-1 expression and cell apoptosis may have an important biological significance in esophageal carcinogenesis.

Roles of Fas signaling pathway in vitamin E succinate-induced apoptosis in human gastric cancer SGC-7901 cells

AIM

To investigate the roles of Fas signaling pathway in vitamin E succinate-induced apoptosis in human gastric cancer SGC-7901 cells.

METHODS

Human gastric cancer SGC-7901 cells were treated with VES at 5, 10, 20 mg x L(-1), succinic acid and vitamin E as vehicle control and condition media only as untreated (UT) control. Apoptotic morphology was observed by DAPI staining. Western blot analysis was applied to measure the expression of Fas, FADD and caspase-8 proteins. After the cells were transiently transfected with Fas and FADD antisense oligonucleotides, respectively, caspase-8 activity was determined by flurometric method.

RESULTS

The morphologically apoptotic changes were observed after VES treatment by DAPI staining. 23.7 % and 89.6 % apoptosis occurred after 24 h and 48 h of 20 mg x L(-1) VES treatment, respectively. The protein levels of Fas, FADD and caspase-8 were evidently increased in a dose-dependent manner after 24 h of VES treatment. The blockage of Fas by transfection with Fas antisense oligonucleotides obviously inhibited the expression of FADD protein. After SGC-7901 cells were transfected with Fas and FADD antisense oligonucleotides, caspase-8 activity was obviously decreased (P<0.01), whereas Fas blocked more than FADD.

CONCLUSION

VES-induced apoptosis in human gastric cancer SGC-7901 cells involves Fas signaling pathway including the interaction of Fas, FADD and caspase-8.

The effects of vitamin E succinate on the expression of c-jun gene and protein in human gastric cancer SGC-7901 cells

AIM

To investigate the effects of vitamin E succinate (VES) on the expression of c-jun gene and protein in human gastric cancer SGC-7901 cells.

METHODS

After SGC-7901 cells were treated with VES at different doses (5,10,20 mg x L(-1)) at different time, reverse transcription-PCR technique was used to detect the level of c-jun mRNA; Western Blot was applied to measure the expression of c-jun protein.

RESULTS

After the cells were treated with VES at 20 mg x L(-1) for 3 h, the expression rapidly reached its maximum that was 3.5 times of UT control (P<0.01). The level of c-jun mRNA was also increased following treatment of VES for 6 h. However,the expression after treatment of VES at 5 mg x L(-1) for 24 h was 1.6 times compared with UT control (P<0.01). Western blot analysis showed that the level of c-jun protein was obviously elevated in VES-treated SGC-7901 cells at 20 mg x L(-1) for 3 h. The expression of c-jun protein was gradually increased after treatment of VES at 20 mg x L(-1) for 3, 6, 12 and 24 h, respectively, with an evident time-effect relationship.

CONCLUSION

The levels of c-jun mRNA and protein in VES-treated SGC-7901 cells were increased in a dose- and time-dependent manner; the expression of c-jun was prolonged by VES, indicating that c-jun is involved in VES-induced apoptosis in SGC-7901 cells.

Seek protein which can interact with hepatitis B virus X protein from human liver cDNA library by yeast two-hybrid system

AIM: To seek the X associated protein (XAP) with the constructed bait vector pAS2-1X from normal human liver cDNA library.

METHODS: The X region of the HBV gene was amplied by PCR and cloned into the eukaryotic expression vector pAS2-1.The reconstituted plasmid pAS2-1X was transformed into the yeast cells and the expression of X protein (pX) was confirmed by Western blot analysis. Yeast cells were cotransformed with pAS2-1X and the normal human liver cDNA library and were grown in selective SC/-trp-leu-his-ade medium, the second screen was performed with the LacZ report gene. Furthermore, segregation analysis and mating experiment were performed to eliminate the false positive and the true positive clones were selected for PCR and sequencing.

RESULTS: Reconstituted plasmid pAS2-1X including the anticipated fragment of X gene was proved by auto-sequencing assay. Western blot analysis showed that reconstituted plasmid pAS2-1X expressed BD:X fusion protein in yeast cells. Of 5 × 10⁶ transformed colonies screened, 65 grew in the selective SC/-trp-leu-his-ade medium, 5 scored positive for β-gal activity, and only 2 remaining clones passed through the segregation analysis and mating experiment. Sequence analysis identified that two clones contained similar cDNA fragment: GAACTTGCG.

CONCLUSION: The short peptide (glutacid-leucine-alanine)is a possible required site for XAP binding to pX. Normal human liver cDNA library has difficulties in expressing the integrated XAP on yeast cells.

RRR-alpha-tocopheryl succinate inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM

To investigate the effects of growth inhibition of human gastric cancer SGC-7901 cell with RRR-alpha-tocopheryl succinate (VES), a derivative of natural Vitamin E, via inducing apoptosis and DNA synthesis arrest.

METHODS

Human gastric cancer SGC-7901 cells were regularly incubated in the presence of VES at 5, 10 and 20mg x L(-1) (VES was dissolved in absolute ethanol and diluted in RPMI 1640 complete condition media correspondingly to a final concentration of VES and 1 mL x L(-1) ethanol), succinic acid and ethanol equivalents as vehicle (VEH) control and condition media only as untreated (UT) control. Trypan blue dye exclusion analysis and MTT assay were applied to detect the cell proliferation. Cells were pulsed with 37kBq of tritiated thymidine and (3H) TdR uptake was measured to observe DNA synthesis. Apoptotic morphology was observed by electron microscopy and DAPI staining. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect VES-triggered apoptosis.

RESULTS

VES inhibited SGC-7901 cell growth in a dose-dependent manner. The growth curve showed suppression by 24.7%, 49.2% and 68.7% following 24h of VES treatment at 5, 10 and 20 mg x L(-1), respectively, similar to the findings from MTT assay. DNA synthesis was evidently reduced by 35%, 45% and 98% after 24h VES treatment at 20mg x L(-1) and 48 h at 10 and 20mg x L(-1), respectively. VES induced SGC-7901 cells to undergo apoptosis with typically apoptotic characteristics, including morphological changes of chromatin condensation, chromatin crescent formation/margination, nucleus fragmentation and apoptotic body formation, typical apoptotic sub-G1 peak by flow cytometry and increase of apoptotic cells by TUNEL assay in which 90% of cells underwent apoptosis after 48 h of VES treatment at 20 mg x L(-1).

CONCLUSION

VES can inhibit human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest. Inhibition of SGC-7901 cell growth by VES is dose- and time-dependent. Therefore VES can function as a potent chemotherapeutic agent against human gastric carcinogenesis.

Expression of liver cancer associated gene HCCA3

AIM: To study and clone a novel liver cancer related gene, and to explore the molecular basis of liver cancer genesis.

METHODS: Using mRNA differential display polymerase chain reaction (DDPCR), we investigated the difference of mRNA in human hepatocellular carcinoma (HCC) and paired surrounding liver tissues, and got a gene probe. By screening a human placenta cDNA library and genomic homologous extend, we obtained a full-length cDNA named HCCA3. We analyzed the expression of this novel gene in 42 pairs of HCC and the surrounding liver tissues, and distribution in human normal tissues by means of Northern blot assay.

RESULTS: A full-length cDNA of liver cancer associated gene HCCA3 has been submitted to the GeneBank nucleotide sequence databases (Accession No. AF276707). The positive expression rate of this gene was 78.6% (33/42) in HCC tissues, and the clinical pathological data showed that the HCCA3 was closely associated with the invasion of tumor capsule (P = 0.023) and adjacant small metastasis satellite nodules lesions (P = 0.041). The HCCA3 was widely distributed in the human normal tissues, which was intensively expressed in lungs, brain and colon tissues, while lowly expressed in the liver tissues.

CONCLUSION: A novel full-length cDNA was cloned and differentiated, which was highly expressed in liver cancer tissues. The high expression was closely related to the tumor invasiveness and metastasis, that may be the late heredited change in HCC genesis.

Extraction and purification of TGFβ and its effect on the induction of apoptosis of hepatocytes

AIM: To extract and purify the transforming growth factor β (TGFβ), and to demonstrate its biological activity in vivo and induction of apoptosis of hepatocytes in vitro.

METHODS: TGFβ was isolated from fresh bovine platelets by acid/ethanol extraction method and purified with ion exchange and gel chromatography. The extracted TGFβ as injected subcutaneously to mice, and its biological activity in vivo was observed 72 hrs post-injection by HE staining. The morphological changes were observed by HE staining and the occurrence of apoptosis was detected by TUNEL method after the human normal hepatic cell line QZG was treated with 8 μg·L^-1TGFβ for 12 hrs in vitro.

RESULTS: The molecular mass 25 ku TGFβ protein was successfully extracted. It was able to induce localized granulation tissue formation in vivo. TGFβ-treated hepatocytes showed obvious apoptotic morphological changes, including the pyknosis and dense-stained nuclei and cytoplasm, the fragmentary, annular or crescent nuclei, and the “bubbling” cytoplasm. Moreover, its apoptotic rate was significantly higher than that of the control group (P < 0.05).

CONCLUSION: Biological active TGFβ protein is extracted and purified successfully from bovine platelets, and it is able to induce the apoptosis of hepatocytes.

Abnormal β-catenin gene expression with invasiveness of primary hepatocellular carcinoma in China

AIM: To study the abnormal expression of β-catenin gene and its relationship with invasiveness of primary hepatocellular carcinoma among Chinese people.

METHODS: Thirty-four hepatocellular carcinoma (HCC) specimens and adjacent paracancerous tissues, 4 normal liver tissues were immunohistochemically stained to study subcellular distribution of β-catenin. Semiquantitive analysis of expression of β-catenin gene exon 3 mRNA was examined by RT-PCR and in situ hybridization. The relationship between expressions of both β-catenin protein, mRNA and clinicopathological characteristics of HCC was also analyzed.

RESULTS: Immunohistochemistry showed that all normal liver tissues and para-cancerous tissues examined displayed membranous type staining for β-catenin protein, occasionally with weak expression in the cytoplasm. While 21 cases (61.8%) of HCC examined showed accumulated type in cytoplasms or nuclei. The accumuled type Labling Index (LI) of cancer tissue and para-cancarous tissue was (59.9 ± 26.3) and (18.3 ± 9.7) respectively (P < 0.01). Higher accumulated type LI was closely related with invasiveness of HCC. Results of RT-PCR showed the β-catenin gene exon 3 mRNA Expression Index (EI) of 34 HCCs was higher than that of para-cancerous tissue and normal liver tissue. Using in situ hybridization, the signal corresponding to β-catenin gene exon 3 mRNA was particularly strong in cytoplasm of HCC when compared with those of para-cancerous and normal liver tissues. Over expression of β-catenin exon 3 was also found to be correlated with high metastatic potential of HCC.

CONCLUSION: Abnormal expression of β-catenin gene may contribute importantly to the invasiveness of HCC among Chinese people.

Molecular mechanism about lymphogenous metastasis of hepatocarcinoma cells in mice

AIM: To investigate the correlation between lymphogenous metastasis and matrix metalloproteinases (MMPs) activity and the expression of Fas ligand of tumor cells in lymph nodes.

METHODS: Fifty-six inbred 615-mice were equally divided into 2 groups and inoculated with Hca-F and Hca-P cells. Their lymph node metastatic rates were examined. Growth fraction of lymphocytes in host lymph nodes was detected by flow cytometry. The Hca-F and Hca-P cells were cultured with extract of lymph node, liver or spleen. The quantity of MMPs in these supernatants was examined by zymographic analysis. The expression of Fas ligand, PCNA, Bcl-2 protein of Hca-F and Hca-P cells in the mice were examined by immunohistochemistry. The apoptosis signals of macrophages in lymph nodes were observed with in situ DNA fragmentation.

RESULTS: On the 28^th day post-inoculation, the lymph node metastatic rate of Hca-F was 80% (16/20), whereas that of Hca-P was 25% (5/20). The growth fraction of lymphocytes was as follows: in the Hca-F cells, the proliferating peak of lymphocytes appeared on the 14^th day post-inoculation and then decreased rapidly, while in Hca-P cells, the peak appeared on the 7^th day post inoculation and then kept at a high level. With the extract of lymph node, the quantity of the MMP-9 activity increased (P < 0.01) and active MMP-9 and MMP-2 were produced by both Hca-F and Hca-P tumor cells, which did not produce MMPs without the extract of lymph node or with the extracts of the liver and spleen. The expression of Fas Ligand of Hca-F cells was stronger than that of Hca-P cells (P < 0.01). The expressions of PCNA and Bcl-2 protein of Hca-F cells in the tumors of inoculated area were the same as that of Hca-P cells. In situ DNA fragmentation showed that the positive signals of macrophages were around Hca-F cells.

CONCLUSION: Secretion of MMPs which was associated with metastatic ability of Hca-F and Hca-P tumor cells depends on the environment of lymph nodes. The increased expression of Fas ligand protein of Hca-F tumor cells with high lymphogenous metastatic potential in lymph nodes may help tumor cells escape from being killed by host lymphocytes.

Effect of arsenic trioxide on human hepatoma cell line BEL-7402 cultured in vitro

AIM: To study the effect of a varying concentrations of arsenic trioxide on human hepatoma cell line BEL-7402 cultured in vitro and its mechanism of action.

METHODS: The BEL-7402 cells were treated with arsenic trioxide (at the concentrations of 0.5, 1, 2 μmol/L, respectively) for 4 successive days. The cell growth and proliferation were observed by cell counting and cell-growth curve. Morphologic changes were studied with electronmicroscopy. Flow cytometry was used to assay cell-DNA distribution and the protein expression of Bcl-2 and Bax detected by immuno cytochemical method.

RESULTS: The cell growth was significantly inhibited by varying concentrations of arsenic trioxide as revealed by cell counting and cell-growth curve, which was dose- and time-dependent. Arsenic trioxide treatment at 0.5, 1 and 2 μmol/L resulted in a sub G1 cell peak, the apoptosis rate of the control group was 9.31% and that of 0.5 μmol/L arsenic trioxide 15.53%, no significant difference was seen between the two. The apoptosis rates of 1, 2 μmol/L arsenic trioxide were 19.10% and 21.87% respectively, which were much higher (both P < 0.05). Decrease of G₀/G₁ phase cells and increase of S phase cells were observed by flow cytometry, suggesting the inhibition effect of 0.5, 1, 2 μmol/L arsenic trioxide on BEL-7402 cell lay in the G₀/G₁ phase. Morphologic changes such as intact cell membrane, nucleic condensation, apoptotic body formation were seen under transmission electronmicrescopy, whereas the 0.5 mol/L arsenic trioxide-treated BEL-7402 cells showed decrease of nucleocytoplasmic ratio, round nucleus, well-differentiated organelles in the cytoplasm. The processes and microvilli on the cell surface of the experimental groups under scanning electron microscopy were significantly decreased. High expressions of Bcl-2 and Bax were detected in 1 and 2 μmol/L arsenic trioxide-treated cells, these were 46%, 87.33% and 83.08%, 95.83% respectively, among which that of Bax was more significant. Arsenic trioxide treatment at 0.5 μmol/L resulted in a higher expression level of Bcl-2 and lower expression level of Bax, which were 8.81% and 3.83% respectively, as compared with that of the control group (15.33%) (P₁ <0.01, P₂ < 0.01).

CONCLUSION: Arsenic trioxide not only inhibited proliferation but also induced apoptosis of human hepatoma cell line BEL-7402. The induced-apoptosis effect of 1, 2 μmol/L arsenic trioxide was related to the expression level of Bcl-2 and Bax.