Early apoptosis in intestinal and diffuse gastric carcinomas

Cytostatic and Antiproliferative Activities of F5 Fraction of Crinum amabile Leaf Chloroform Extract Showed Its Potential as Cancer Chemotherapeutic Agent

Medicinal plants have been considered as promising sources of drugs in treating various cancers. Crinum amabile (C. amabile), a plant species from the Amaryllidaceae family, is claimed to be a potential source for cancer chemotherapeutic compounds. Here, we aimed to investigate the potential of C. amabile as an anticancer agent. Dried leaves of C. amabile were serially extracted and our findings showed that chloroform extract (CE) was shown to exhibit cytotoxic effect against all cancer cell lines used. This active extract was further fractionated in which F5 fraction was shown to possess the highest cytotoxicity among all fractions. F5 fraction was then tested in-depth through Annexin V/FITC apoptosis and DNA fragmentation assays to determine its apoptotic effect on MCF-7 cells. Results revealed that F5 fraction only showed induction of cell apoptosis starting at 72-hour treatment while DNA fragmentation was not detected at any of the concentrations and treatment periods tested. Meanwhile, cell proliferation assay revealed that F5 fraction was able to inhibit normal cell proliferation as well as VEGF-induced cell proliferation of normal endothelial cell (HUVECs). In conclusion, F5 fraction from C. amabile leaf CE was able to exhibit cytostatic effect through antiproliferation activity rather than induction of cell apoptosis and therefore has the potential to be further investigated as an anticancer agent.

Xiao Tan He Wei Decoction reverses MNNG-induced precancerous lesions of gastric carcinoma in vivo and vitro: Regulation of apoptosis through NF-κB pathway

In recent years, Chinese medicine has played an important role in the prognosis of gastric cancer. Precancerous lesions of gastric carcinoma (PLGC) is a class of gastric cancer which is closely related to the gastric mucosal pathology changes in the role of carcinogenic incentives, and plays key role in the progression of normal gastric mucosal cells into gastric cancerous cells. In current experiment, we explore the relationship between Chinese traditional medicine (Xiao Tan He Wei Decoction) and gastric cancer in the PLGC rat animal models and epithelial-mesenchymal transitioned GES-1 cells which were induced useing 1- Methyl-3-nitro-1-nitrosoguanidine (MNNG). PLGC rat model showed significant deterioration in the gastric mucosa with terrible growth rate in body weight and more atypical hyperplasia in gastric mucosa. MC cells, MNNG induced GES-1 cells which epithelial- mesenchymal-transition (EMT)-related proteins have a great change compare with normal GES-1 cells. The cells had characteristics of malignant cells including proliferation, invasion and metastasis ability. Our research founds that Xiao Tan He Wei Decoction could inhibit cell proliferation and increased apoptosis by increase the level of pro-apoptotic proteins like Bax and caspase-3 and decreased the level of anti-apoptotic protein Bcl-2, block the cells in G0/G1 phase simultaneously. Furthermore, Xiao Tan He Wei Decoction could inhibit nuclear factor kappa-light-chain-enhancer (NF-kB) activity and inhibit its transfer from the cytoplasm to the nucleus. However, when we incubated with NF-κB activator PMA, the effect of Xiao Tan He Wei Decoction was reversed. These results suggested that Xiao Tan He Wei Decoction could be used as a method for the treatment of gastric precancerous lesions, and possibly provide a theoretical basis for the clinical treatment of gastric cancer and gastric precancerous lesions.

RESISTIN EFFECT ON TELOMERASE GENE EXPRESSION IN GASTRIC CANCER CELL LINE AGS

Background

Resistin, as an adipokine, has been shown to be increased in serum plasma of gastric cancer patients and suggested to be a major factor in gastric carcinogenesis. However, it is still not clear how Resistin influences gastric cancer progression. The aim of this study was to evaluate Resistin effect on cell proliferation and expression of telomerase gene in gastric cancer cell line (AGS).

Methods

In this study, the proliferating activity of AGS cells stimulated with Resistin was also evaluated by using 2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) assay and trypan blue staining method. To investigate telomerase gene expression affected by Resistin, total RNA was extracted, cDNA was synthesized and expression of hTERT mRNA was carried out by real-time reverse transcription polymerase chain reaction.

Results

Exogenous Resistin has induced gastric cancer cells proliferation in a dose-dependent manner and could improve cell viability. Also the expression of Human Telomerase Reverse Transcriptase (hTERT) was upregulated in 24 hours, after Resistin treatment.

Conclusions

This study has shown Resistin induces exogenously gastric cancer cell proliferation and increases hTERT gene expression. These findings may clarify the role of Resistin in gastric carcinogenesis. Therefore blocking Resistin signaling and limiting its secretion may be valuable for the treatment of gastric cancer.

Mutations of mitochondrial 12S rRNA in gastric carcinoma and their significance

AIM: To detect the variations of mitochondrial 12S rRNA in patients with gastric carcinoma, and to study their significance and the relationship between these variations and the genesis of gastric carcinoma.

METHODS: PCR amplified mitochondrial 12S rRNA of 44 samples including 22 from gastric carcinoma tissues and 22 from adjacent normal tissues, was detected by direct DNA sequencing. Then laser capture microdissection technique (LCM) was used to separate the cancerous cells and dysplasia cells with specific mutations. Denaturing high performance liquid chromatography (DHPLC) plus allele-specific PCR (AS-PCR), nest-PCR and polyacrylamide gel electrophoresis (PAGE) were used to further evaluate this mutant property and quantitative difference of mutant type between cancerous and dysplasia cells. Finally, RNAdraw biosoft was used to analyze the RNA secondary structure of mutant-type 12S rRNA.

RESULTS: Compared with Mitomap database, some new variations were found, among which np652 G insertion and np716 T-G transversion were found only in cancerous tissues. There was a statistic difference in the frequency of 12S rRNA variation between intestinal type (12/17, 70.59%) and diffusive type (5/17, 29.41%) of gastric carcinoma (P<0.05). DHPLC analysis showed that 12S rRNA np652 G insertion and np716 T-G transversion were heteroplasmic mutations. The frequency of 12S rRNA variation in cancerous cells was higher than that in dysplasia cells (P<0.01). 12S rRNA np652 G insertion showed obviously negative effects on the stability of 12S rRNA secondary structure, while others such as T-G transversion did not.

CONCLUSION: The mutations of mitochondrial 12S rRNA may be associated with the occurrence of intestinal-type gastric carcinoma. Most variations exist both in gastric carcinomas and in normal tissues, and they might not be the characteristics of tumors. However, np652 G insertion and np716 T-G transversion may possess some molecular significance in gastric carcinogenesis. During the process from normality to dysplasia, then to carcinoma, 12S rRNA tends to convert from homoplasmy (wild type) to heteroplasmy, then to homoplasmy (mutant type, np717 T-G).

Morphology of apoptosis of human hepatocellular carcinoma cell line induced by 2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose

AIM: To investigate the changes of apoptosis in hepatocellular carcinoma cells induced by 2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose.

METHODS: Fluorescent microscopy and transmission electron microscopy were used to observe the morphologic changes of apoptosis with different concentration of2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose at different time.

RESULTS: The morphologic changes of apoptosis were exhibited, including shrinkage of cell, condensation of chromatin, breakage of nuclear and formation of apoptotic bodies, but the number of apoptosis increased with the concentration 2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose and time.

CONCLUSION: 2-[(3-carboxy-1-oxoprogy1) amino]-2-deoxy-D-glucose can induce apoptosis of human hepatocelluar carcinoma cells (HepG2).

Variations of mitochondrial D-loop region plus downstream gene 12S rRNA-tRNAphe and gastric carcinomas

AIM: To explore the instabilities, polymorphisms and other variations of mitochondrial D-loop region and downstream gene 12S rRNA-tRNA^phe in gastric cancers, and to study their relationship with gastric cancer.

METHODS: Three adjacent regions (D-loop, tRNA^phe and 12S rRNA) were detected for instabilities, polymorphisms and other variations via PCR amplification followed by direct DNA sequencing in 22 matched gastric cancerous tissues and para-cancerous normal tissues.

RESULTS: PolyC or (CA)_n instabilities were detected in 13/22(59.1%) gastric cancers and 9/22(40.9%) in the control (P > 0.05). There existed 2/12(16.7%) and 6/10(60%) alterations of 12S rRNA-tRNA^phe in well differentiated gastric cancers and poorly differentiated ones, respectively (P < 0.05). Some new variations were found, among which np 318 and np 321 C-T transitions in D-loop region were two of the five bases for H-strand replication primer. np 523 AC-deletion and np 527 C-T transition occurred at mtTF1 binding site (mtTFBS), which were associated with the transcription of downstream mitochondrial genome. Seven samples showed the np 16182 polyC instabilities, five of which simultaneously showed np 16189 T-C transitions.

CONCLUSION: There is no statistic significance of instabilities and polymorphisms in mitochondrial D-loop region between gastric cancerous and para-cancerous normal tissues, which suggests that the instability might relate to heredity or be dependent on aging. There is a significant correlation between differentiation degree of gastric cancer and variant frequencies of 12S rRNA-tRNA^phe. The poorly differentiated gastric cancers are more prone to 12S rRNA-tRNA^phe variations, or gastric cancers with 12S rRNA-tRNA^phe variations are more likely to be poorly differentiated. np 16189 T-C transition may be one of the important reasons for polyC instability in gastric cancer.

Effects of allicin on both telomerase activity and apoptosis in gastric cancer SGC-7901 cells

AIM: To investigate the effects of allicin on both telomerase activity and apoptosis in gastric cancer SGC-7901 cells.

METHODS: The gastric cancer SGC-7901 adenocarcinoma cells were treated with allicin and the cell cycle, inhibitory rate, apoptosis, telomerase activity and morphologic changes were studied by MTT assay, flow cytometry (FCM), TRAP-PCR-ELISA assay, light microscope, electron microscope respectively. Results were compared with that of AZT (3’-Azido-3’-deoxythymidine).

RESULTS: SGC-7901 cells were suppressed after exposure to allicin of 0.016 mg/mL, 0.05 mg/mL, and 0.1 mg/mL for 48 h. Compared with the control, the difference was significant (P < 0.05). Allicin could induce apoptosis of the cells in a dose-dependent and non-linear manner and increase the proportion of cells in the G₂/M phase. Compared with the control, the difference was significant in terms of the percentage of cells in the G₂/M phase (P < 0.05). Allicin could inhibit telomerase activity in a time-dependent and dose-dependent pattern. After exposure to allicin at 0.016 mg/mL for 24 hours, SGC-7901 cells showed typical morphologic change.

CONCLUSION: Allicin can inhibit telomerase activity and induce apoptosis of gastric cancer SGC-7901 cells. Allicin may be more effective than AZT.

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.

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Tributyrin inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM

To evaluate the effects of tributyrin, a pro-drug of natural butyrate and a neutral short-chain fatty acid triglyceride, on the growth inhibition of human gastric cancer SGC-7901 cell.

METHODS

Human gastric cancer SGC-7901 cells were exposed to tributyrin at 0.5, 1, 2, 5, 10 and 50 mmol/L(-1) for 24-72 h. MTT assay was applied to detect the cell proliferation. [(3)H]-TdR uptake was measured to determine DNA synthesis. Apoptotic morphology was observed by electron microscopy and Hoechst-33258 staining. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect tributyrin-triggered apoptosis. The expressions of PARP, Bcl-2 and Bax were examined by Western blot assay.

RESULTS

Tributyrin could initiate growth inhibition of SGC-7901 cell in a dose- and time-dependent manner. [(3)H]-TdR uptake by SGC-7901 cells was reduced to 33.6 % after 48 h treatment with 2 mmol/L(-1) tributyrin, compared with the control (P<0.05). Apoptotic morphology was detected by TUNEL assay. Flow cytometry revealed that tributyrin could induce apoptosis of SGC-7901 cells in dose-dependent manner. After 48 hours incubation with tributyrin at 2 mmol/L(-1), the level of Bcl-2 protein was lowered, and the level of Bax protein was increased in SGC-7901, accompanied by PARP cleavage.

CONCLUSION

Tributyrin could inhibit the growth of gastric cancer cells effectively in vitro by inhibiting DNA synthesis and inducing apoptosis, which was associated with the down-regulated Bcl-2 expression and the up-regulated Bax expression. Therefore, tributyrin might be a promising chemopreventive and chemotherapeutic agent against human gastric carcinogenesis.

The effects of the formula of amino acids enriched BCAA on nutritional support in traumatic patients

AIM: To investigate the formula of amino acid enriched BCAA on nutritional support in traumatic patients after operation.

METHODS: 40 adult patients after moderate or large abdominal operations were enrolled in a prospective, randomly and single-blind-controlled study, and received total parenteral nutrition (TPN) with either formula of amino acid (AA group, 20 cases) or formula of amino acid enriched BCAA (BCAA group, 20 cases). From the second day after operation, total parenteral nutrition was infused to the patients in both groups with equal calorie and equal nitrogen by central or peripheral vein during more than 12 hours per day for 6 days. Meanwhile, nitrogen balance was assayed by collecting 24 hours urine for 6 days. The markers of protein metabolism were investigated such as amino acid patterns, levels of total protein, albumin, prealbumin, transferrin and fibronectin in serum.

RESULTS: The positive nitrogen balance in BCAA group occurred two days earlier than that in AA group. The serum levels of total protein and albumin in BCAA group were increased more obviously than that in AA group. The concentration of valine was notably increased and the concentration of arginine was markedly decreased in BCAA group after the formula of amino acids enriched BCAA transfusion.

CONCLUSION: The formula of amino acid enriched BCAA may normalize the levels of serum amino acids, reduce the proteolysis, increase the synthesis of protein, improve the nutritional status of traumatic patients after operation.

Intravenous chemotherapy for resected gastric cancer: meta-analysis of randomized controlled trials

AIM: To assess the safety and efficacy of different intravenous chemotherapeutic regimens in patients with gastric carcinomas who had undergone gastrectomy.

METHODS: A meta-analysis of all the relevant randomized controlled trials (RCTs) was performed. Language was restricted to Chinese and English. RCTs were identified from Medline and Embase (1980-2001/4), and Chinese Bio-medicine Database (1990-2001/1). Literature references were checked at the same time. We included randomized and quasi-randomized trials comparing the efficacy of intravenous chemotherapy after gastrectomy with that of surgery alone in patients with confirmed gastric carcinomas who had undergone gastrectomy. Selection criteria were: randomized or quasi-randomized trials with following-up results; Trials could be double-blind, single-blind or not blind; Chemotherapy groups were given intravenous chemotherapy after gastrectomy without neo-adjuvant chemotherapy, intraperitoneal hyperthermic perfusion, radiotherapy or chemoimmunotherapy; Controlled group included those receiving gastrectomy alone. The following data were extracted: the number of survival and death by the end of the follow-up; the different agents and doses of the intravenous chemotherapy; the baseline of the chemotherapy group and the controlled arm; the serious adverse events; the statistical consideration; cost-effectiveness analysis. The statistical analysis was performed by RevMan4.1 software which was provided by the Cochrane Collaboration. A P value of < 0.05 was considered statistically significant. Meta-analysis was done with random effects model. Heterogeneity was checked by chi-square test. Sensitivity analysis was performed by excluding the trials in which Jadad-scale was only 1 score. The result was expressed with odds ratio (OR) for the categorical variable.

RESULTS: Fourteen trials involving 4543 patients were included. Meta-analysis was done with random effects model Heterogeneity and sensitivity analysis were performed also. The effect of intravenous chemotherapy after gastrectomy was better than surgery alone (odds ratio 0.56, 95%CI 0.40-0.79). There was a significant difference between the two groups by u-test (P = 0.0008). Sensitivity analysis revealed the same difference (odds ratio 0.81, 95%CI 0.70-0.94). Of fourteen trials, only three studies were of high quality according to the Jadad-scale (with three score). There was one meta-analysis trial and the others, about ten trials, were of low quality. There was no trial which mentioned sample-size calculation, allocation concealment, intention-to-treat analysis. Most of the trials didn’t describe the blind-procedure. There were five trials which detailed the side-effects according to the toxicity grade by WHO standard. The side-effects halting treatment were haematologic and biochemical toxicity, debilitating nausea and vomiting. There were two patients died of chemotherapy toxicity.

CONCLUSION: Based on the review, intravenous chemotherapy after gastrectomy may have positive treatment effect on gastric cancer. However, the evidence is not strong because of the general low methodologic quality of the RCTs. Therefore, we can’t make the conclusion that intravenous chemotherapy after gastrectomy may have better treatment effect on gastric cancer than that of surgery alone. Rigorously designed, randomised, double-blind, placebo-controlled trials are required.

The expression of hTERT mRNA and cellular immunity in gastric cancer and precancerosis

AIM: To observe the expression of Human telomerase reverse transcriptase (hTERT) in gastric carcinomas and precancerosis lesions, to evaluate the immune state of such patients, and to then study the clinical significance of hTERT and immune state for the diagnosis, treatment and prognosis of gastric cancer.

METHODS: In situ hybridization was used to detect the expression of hTERT mRNA in 116 endoscopic of gastric mucosa. Analyzed tissue samples were as follows: 30 cases of chronic superficial gastritis (CSG), 44 of precancerosis lesions (including 27 of chronic atrophic gastritis, 8 of adenomatous polyp and 9 of gastric ulcer) and 42 of gastric cancer (GC). In addition, the T lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺) and natural killer cells (NK) in peripheral blood were determined by flow cytometric analysis (FCM) in 30 cases of CSG, 27 of precancerosis (chronic atrophic gastritis, CAG), and 42 of GC. The data were compared with those of normal control (NC).

RESULTS: The detected positive rate of hTERT varied as follows: 86% (36/42) in GC, 36% (16/44) in precancerosis lesions and 0% (0/30) in CSG. The expression of hTERT mRNA was not associated with patient gender, tumor location, macroscopic type, lymph node metastasis, or degree of differentiation. It was found that the CD3⁺, CD4⁺ of the CSG group were lower than that of NC (P < 0.05). Meanwhile, the T lymphocyte subsets (CD3⁺, CD4⁺, CD4⁺/CD8⁺ ratio) and NK cells of CAG were remarkably lower than that of NC and CSG groups (P < 0.05-0.01). Values of T cells and NK cells of the GC group were significantly abnormal when compared with the CAG group (P < 0.05-0.01). Furthermore, with tumor progression, the function of T cells was weakened gradually.

CONCLUSION: The expression of telomerase may be a crucial step in gastric carcinogenesis and increased hTERT mRNA may serve as a novel marker for diagnosis of GC. The immune state of patients with GC and precancerosis was somewhat depressed, which indicates the importance of cellular immunological assays in cancer patients.

Effect of cis-9, trans-11-conjugated linoleic acid on cell cycle of gastric adenocarcinoma cell line (SGC-7901)

AIM

To determine the effect of cis -9, trans -11-conjugated linoleic acid (c9, t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth.

METHODS

Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B(1), D(1), p16(ink4a) and p21(cip/waf1) of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25, 50, 100 and 200 micromol.L(-1))of c 9, t 11-CLA for 24 and 48h, with a negative control (0.1% ethane).

RESULTS

The cell growth and DNA synthesis of SGC-7901 cells were inhibited by c9, t11-CLA.SGC-7901 cells. Eight day after treatment with various concentrations of c9, t11-CLA mentioned above, the inhibition rates were 5.92%, 20.15%, 75.61% and 82.44%, respectively and inhibitory effect of c9, t11-CLA on DNA synthesis (except for 25 micromol.L, 24h) showed significantly less (3)H-TdR incorporation than that in the negative controls (P<0.05 and P<0.01). Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations at various times significantly decreased the expressions of PCNA (the expression rates were 7.2-3.0%, 24h and 9.1-0.9% at 48h, respectively), Cyclin A (11.0-2.3%, 24h and 8.5-0.5%,48h), B(1) (4.8-1.8% at 24h and 5.5-0.6% at 48h)and D(1) (3.6-1.4% at 24h and 3.7%-0 at 48h) as compared with those in the negative controls(the expressions of PCNA, Cyclin A, B(1) and D(1) were 6.5% at 24h and 9.0% at 48h, 4.2% at 24h and 5.1% at 48h, 9.5% at 24h and 6.0% at 48h,respectively)(P<0.01), whereas the expressions of P16(ink4a) and P21(cip/waf1), cyclin-dependent kinases inhibitors(CDKI), were increased.

CONCLUSION

The cell growth and proliferation of SGC-7901 cell is inhibited by c9, t11-CLA via blocking the cell cycle, with reduced expressions of cyclin A,B(1) and D(1) and enhanced expressions of CDKI(P16(ink4a) and p21(cip/waf1)).