A major polyphenol of green tea, epigallocatechin-3-gallate (EGCG), has previously been shown to induce cell-cycle arrest and apoptosis in various cancers. However, little is known about its effects ...on hepatocellular carcinomas (HCCs).
Four HCC cell lines, HLE, HepG2, HuH-7 and PLC/PRF/5, were treated with EGCG or vehicle. Cell viability was assessed by trypan blue staining and WST-8 assay. Cell-cycle, apoptosis and apoptosis-related proteins in HLE cells were evaluated by flow cytometry and Western blotting. The effect of EGCG was also studied in vivo using a xenograft model. The effect of co-treatment with EGCG and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was also assessed.
EGCG inhibited the growth of all HCC cell lines at concentrations of 50–100
μg/ml. In HLE cells, EGCG induced apoptosis but not cell-cycle arrest and appears to have down-regulated Bcl-2α and Bcl-xl by inactivation of NF-κB. Oral administration of EGCG showed similar effects in HLE xenograft tumors. Co-treatment with EGCG and TRAIL synergistically induced apoptosis in HLE cells.
EGCG induced apoptosis in HLE cells, both in vitro and in vivo. Moreover, it enhanced TRAIL-induced apoptosis. Therefore, EGCG treatment may be useful for improving the prognosis of HCCs.
: Aims: The risk factors associated with poor prognosis of nonalcoholic fatty liver disease (NAFLD) are not fully understood. Our aim was to assess the role of progressive hepatocellular telomere ...shortening in the clinical course of NAFLD.
Methods: We measured average telomere lengths in liver tissue samples from 44 patients with NAFLD by quantitative fluorescence in situ hybridization using a telomere‐specific probe. Patients in which telomeres measured at least 80% of the lengths of age‐matched controls were categorized as group A. Those patients with telomeres measuring less than 80% of the control lengths formed group B.
Results: Within group B, some samples showed a remarkable shortening of hepatocyte telomeres in younger patients, whereas some group A patients showed almost normal telomere lengths until their seventies. Among clinicopathological factors, body mass index (BMI), homeostasis model assessment insulin resistance (HOMA‐IR), histological degree of steatosis and intensity of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) immunostaining were all significantly higher in group B than in group A. Ki‐67 immunohistochemistry demonstrated that group B liver tissues were significantly less proliferative than those from group A, despite no significant difference in the necroinflammatory activities of group A and B samples. In group B patients, the ratios of Ki‐67 positive index to alanine aminotransferase value were significantly lower than group A.
Conclusions: Greater insulin resistance can result in more severe hepatic steatosis among group B patients, leading to an overproduction of reactive oxygen species, which may accelerate telomere erosion. Furthermore the regenerative response of hepatocytes with prominent telomere shortening may be impaired, making these cells vulnerable to the effect of a ‘second‐hit’ insult.
: Aim: Our aim was to clarify the significance of expression levels and post‐transcriptional splicing patterns of survivin during multistep hepatocarcinogenesis and tumor progression.
Methods: Using ...immunohistochemistry, we first elucidated the expression of survivin protein in tissues of hepatocellular carcinoma (HCC) and the adjacent non‐cancerous tissues. Furthermore, we investigated survivin gene expression patterns in these tissues.
Results: Survivin protein was expressed not only in most HCC tissues but also in some cirrhotic nodules. In non‐cancerous regions, the levels of survivin mRNA increased in proportion to their stage of progression. Survivin protein was expressed mainly in periportal areas, where proliferating cells were localized. In HCC, mRNA levels of survivin and survivin ΔEx3 correlated with high proliferative activity, whereas the levels of surviving 2B did not.
Discussion: These findings of mRNA and protein expressions of survivin in chronically injured avers indicate that it has an important role in hepatocarcinogenesis. A lack of correlation between proliferative activity and survivin 2B mRNA levels in HCC is suggestive of a previous hypothesis that this variant decreases sruvivin function in a dominan negative manner. Thus, our data suggest different functions of these splicing variants and their important roles in tumor progression.
Centrosome duplication is controlled in a cell cycle-specific manner and occurs once every cell cycle, thereby ensuring the balanced segregation of chromosomes during the mitotic phase. Numerical or ...structural abnormalities can arise in the centrosomes of malignant cells. Under defective cell cycle checkpoint systems, cancer cells with abnormal centrosomes can survive and re-enter the cell cycle, promoting unbalanced chromosome segregation and genetic instability. We investigated the centrosome aberrations in 33 patients diagnosed with hepatocellular carcinoma (HCC), using fluorescent pericentrin immunostaining. We also studied the p53 mutation, proliferative activity, and DNA ploidy in these cases. In normal hepatocytes, one centrosome was identified per cell as a round dot, usually in the vicinity of the nuclear membrane. However, in cancer cells from HCC tissue, several patterns of centrosome abnormalities occurred, including supernumerary centrosomes and centrosomes with an abnormal shape and size. Although the frequency of abnormal centrosomes in each tissue was relatively low compared with previous reports in other cancers, nevertheless, centrosome aberration was found in 30 out of 33 HCC tissues. The percentage of tumor cells with abnormal centrosomes was significantly higher in the nondiploid tumors (15.8±15.9‰) than in the diploid tumors (5.4±5.1‰) (P<0.05), and tended to be higher in the tumors with p53 mutation (11.6±13.1‰) than in those with wild-type p53 (5.6±6.8‰). Furthermore, 82% of nondiploid tumors exhibited p53 mutation, whereas only 41% of diploid tumors showed p53 mutation. The percentage of tumor cells with centrosome abnormalities were not related to tumor stage, size or proliferative activity. Therefore, our results indicate that hepatic cancer cells, under centrosome aberration and a defective checkpoint system possibly caused by p53 mutation, have the potential for genetic instability and aggressive behavior. This potential effect occurs irrespective of the tumor size or stage.
Using quantitative fluorescence in situ hybridization (Q-FISH), the average telomere length of hepatoma cells was assessed by the average telomeric signal intensity of cancer cells relative to that ...of stromal cells. We demonstrated first the applicability of Q-FISH for tissue sections by comparing Q-FISH and Southern blotting results. Tumors less than 50
mm in diameter and with a relative telomeric intensity of less than 0.6 were categorized as group A and the remainder as group B. In group A, the telomere length correlated negatively with tumor size, whereas in group B there was no correlation. Compared with the group A tumors, the group B tumors were of significantly more advanced stage, showed higher telomerase and proliferative activities, and exhibited less differentiated histology. Therefore, we considered that a lack of correlation between telomere length and tumor size, namely, size-independence of telomere length, is associated with unfavorable clinicopathological features of hepatocellular carcinomas.
We report two patients with gastrointestinal stromal tumors (GISTs) of the small intestine that expressed c-kit protein (CD117). One was a 68-year-old woman with epigastralgia and vomiting. A ...submucosal tumor of the upper jejunum was detected, and partial resection was carried out. The histology revealed a GIST negative for CD34 but positive for CD117. The other was a 42-year-old woman with progressive anemia, melena and lower abdominal pain. Intussusception was detected, and a partial resection was carried out. A submucosal tumor of the lower jejunum was noted. The histology revealed a GIST positive for both CD34 and CD117. (Internal Medicine 39: 914-919, 2000)
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