Induction Of Apoptotic Cells Research Articles

Inhibitory effects of Centella asiatica on azoxymethane-induced aberrant crypt focus formation and carcinogenesis in the intestines of F344 rats

Effects of the water extract of Centella asiatica Linn. on formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF) and intestinal tumorigenesis in male F344 rats were investigated. Treatment with the extract significantly decreased the number of larger ACF (with four or more crypts per focus) in the large intestine in the early stage, while the number of methylated DNA adducts was not decreased compared with that in the AOM-treated group. In the post-initiation stage, the extract significantly decreased the total number of ACF and the number of larger ACF, accompanied by a decrease in the 5-bromo-2′-deoxyuridine-labeling index and an increase in the induction of apoptotic cells in the colonic mucosa. The incidences of neoplasms, the numbers of adenocarcinomas in the small intestines and entire intestines, and sizes of neoplasms in the entire intestines in rats fed C. asiatica extract at a dose of 10mg/kg were smaller than those in rats given AOM alone (p<0.05). The extract at a dose of 100mg/kg significantly reduced the multiplicity of neoplasms in the small intestine (p<0.05). These results suggest that inhibition of the formation of AOM-induced ACF by C. asiatica extract is associated with modification of cell proliferation and induction of apoptosis in colonic crypts and that the extract has a chemopreventive effect on colon tumorigenesis.

DNA fragmentation, DNA repair and apoptosis induced in primary rat hepatocytes by dienogest, dydrogesterone and 1,4,6-androstatriene-17β-ol-3-one acetate

Four steroids that share the 17-hydroxy-3-oxopregna-4,6-diene structure – cyproterone acetate, chlormadinone acetate, megestrol acetate, and potassium canrenoate – have been shown previously to behave with different potency as liver-specific genotoxic agents, the response being markedly higher in female than in male rats, but similar in humans of both genders. In this study, performed to better define the relationship between chemical structure and genotoxicity, dydrogesterone (DGT) with double bonds C4 C5 and C6 C7, dienogest (DNG) with double bonds C4 C5 and C9 C10, and 1,4,6-androstatriene-17β-ol-3-one acetate (ADT) with double bonds C1 C2, C4 C5 and C6 C7, were compared with cyproterone acetate (CPA) for their ability to induce DNA fragmentation and DNA repair synthesis in primary cultures of hepatocytes from three rats of each sex. At subtoxic concentrations, ranging from 10 to 90 μM, all four steroids consistently induced a dose-dependent increase of DNA fragmentation, which in all cases was higher in females than in males; their DNA damaging potency decreased in the order CPA > DNG > ADT > DGT. Under the same experimental conditions, the responses provided by the DNA repair-synthesis assay were positive or inconclusive in hepatocytes from female rats and consistently negative in hepatocytes from male rats. In the induction of apoptotic cells, examined in primary hepatocytes from female rats, CPA was more active than ADT and DGT, and DNG was inactive. Considered as a whole these findings suggest that a liver-specific genotoxic effect more marked in female than in male rats might be a common property of steroids with two or three double bonds.

Metallothionein (I/II) suppresses genotoxicity caused by dimethylarsinic acid

Arsenic is an environmental chemical of considerable concern due to its association with an increased risk of human cancer. Dimethylarsinic acid (DMAA) is one of the major methylated metabolites of ingested arsenicals in most mammals. To better clarify the role of metallothionein (MT) in modifying DMAA genotoxicity, MT-I/II null mice, and the corresponding wild-type mice, were exposed to DMAA (0, 188, 375 or 750 mg/kg body weight) via a single oral dose. Twenty-four hours after the DMAA injection, there was increased formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in serum and urine and a higher number of DNA strand breaks in peripheral blood cells. These increased levels were concomitant with increasing dose concentrations of DMAA in both strains of mice and they were significantly higher in MT-I/II null mice than in wild-type mice. Furthermore, the induction of apoptotic cells in the urinary bladder epithelium of MT-I/II null mice was significantly higher than in dose-matched wild-type mice exposed to DMAA. On the other hand, in both liver and in the alveolar and bronchial areas of the lung, the extent of DMAA-induced apoptosis was not different between wild-type and MT-I/II null mice and was increased in both strains. In addition, the concentration of hepatic MT in wild-type mice increased in a DMAA dose-dependent manner but was undetectable in MT-I/II null mice and could not subsequently be induced by DMAA. In conclusion, DMAA exposure causes oxidative stress, DNA damage and specific induction of apoptosis in target organs of arsenic carcinogenesis, which may be attributable to the mechanism(s) of arsenic-induced carcinogenesis in rodents. MT exhibited some protective roles during DNA damage presumably by acting as an antioxidant.

Expression of insulin-like growth factor binding protein-3 before and after neoadjuvant hormonal therapy in human prostate cancer tissues: correlation with histopathologic effects and biochemical recurrence

Objectives To determine the effects of neoadjuvant hormonal therapy (NHT) on insulin-like growth factor binding protein (IGFBP)-3 expression and whether IGFBP-3 expression influences the pathologic effect of NHT and biochemical recurrence after radical prostatectomy in patients with prostate cancer. IGFBP-3 has pro-apoptotic activity, and its expression correlates negatively with prostate cancer cell growth. Castration induces IGFBP-3 expression and apoptosis in the rat prostate. Methods We used tissue specimens from 42 patients who underwent NHT and radical prostatectomy. The pre-NHT and post-NHT specimens were examined for expression of IGFBP-3 using an immunohistochemical technique and for apoptosis using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method. The histopathologic effect was evaluated by the standardized rules for estimating the response of prostate cancer to NHT, determined by the percentage of remaining viable cancer cells, as advocated by the General Rule for Clinical and Pathological Study on Prostate Cancer published by the Japanese Urological Association. Results NHT resulted in a statistically significant increase in IGFBP-3 expression compared with baseline ( P = 0.01). Such an increase in expression correlated significantly with the induction of apoptotic cells ( r = 0.40 and P = 0.01). The post-NHT/pre-NHT IGFBP-3 ratio was significantly greater in the NHT-effective group than in the NHT-noneffective group ( P = 0.02). Patients with high IGFBP-3 expression in the post-NHT specimens had a good prognosis ( P = 0.03, log-rank test). Conclusions Induction of IGFBP-3 by NHT was associated with apoptosis and a histopathologic effect. IGFBP-3 expression in post-NHT specimens is a potentially useful predictor of biochemical recurrence in patients with prostate cancer.

A major constituent of green tea, EGCG, inhibits the growth of a human cervical cancer cell line, CaSki cells, through apoptosis, G(1) arrest, and regulation of gene expression.

A constituent of green tea, (-)-epigallocatechin-3-gallate (EGCG) has been known to possess antiproliferative properties. In this study, we investigated the anticancer effects of EGCG in human papillomavirus (HPV)-16 associated cervical cancer cell line, CaSki cells. The growth inhibitory mechanism(s) and regulation of gene expression by EGCG were also evaluated. EGCG showed growth inhibitory effects in CaSki cells in a dose-dependent fashion, with an inhibitory dose (ID)(50) of approximately 35 microM. When CaSki cells were further tested for EGCG-induced apoptosis, apoptotic cells were significantly observed after 24 h at 100 microM EGCG. In contrast, an insignificant induction of apoptotic cells was observed at 35 microM EGCG. However, cell cycles at the G1 phase were arrested at 35 microM EGCG, suggesting that cell cycle arrests might precede apoptosis. When CaSki cells were tested for their gene expression using 384 cDNA microarray, an alteration in the gene expression was observed by EGCG treatment. EGCG downregulated the expression of 16 genes over time more than twofold. In contrast, EGCG upregulated the expression of four genes more than twofold, suggesting a possible gene regulatory role of EGCG. This data supports that EGCG can inhibit cervical cancer cell growth through induction of apoptosis and cell cycle arrest as well as regulation of gene expression in vitro. Furthermore, in vivo antitumor effects of EGCG were also observed. Thus, EGCG likely provides an additional option for a new and potential drug approach for cervical cancer patients.

Protective role of metallothionein (I/II) against pathological damage and apoptosis induced by dimethylarsinic acid.

To better clarify the main target organs of dimethylarsinic acid toxicity and the role of metallothionein (MTs) in modifying dimethylarsinic acid (DMAA) toxicity. MT-I/II null (MT(-/-)) mice and the corresponding wild-type mice (MT(+/+)), six in each group, were exposed to DMAA (0-750 mg/kg body weight) by a single oral injection. Twenty four hours later, the lungs, livers and kidneys were collected and undergone pathological analysis, induction of apoptotic cells as determined by TUNEL and MT concentration was detected by radio-immunoassay. Remarkable pathological lesions were observed at the doses ranging from 350 to 750 mg/kg body weight in the lungs, livers and kidneys and MT(+/+) mice exhibited a relatively slight destruction when compared with that in dose matched MT(-/-) mice. The number of apoptotic cells was increased in a dose dependent manner in the lungs and livers in both types of mice. DMAA produced more necrotic cells rather than apoptotic cells at the highest dose of 750 mg/kg, however, no significant increase was observed in the kidney. Hepatic MT level in MT(+/+) mice was significantly increased by DMAA in a dose-dependent manner and there was no detectable amount of hepatic MT in untreated MT(-/-) mice. DMAA treatment can lead to the induction of apoptosis and pathological damage in both types of mice. MT exhibits a protective effect against DMAA toxicity.

Lung cancer prevention with (-)-epigallocatechin gallate using monitoring by heterogeneous nuclear ribonucleoprotein B1

Considering the problems involved in prevention of human lung cancer, growth inhibition of human lung cancer cell line A549 was studied with emphasis on two parameters: green tea polyphenols, such as (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG); and heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1), a new biomarker of human lung cancer which is highly expressed in the very early stages of human lung cancer. The inhibitory potencies of green tea polyphenols were compared with those of genistein as a control. EGCG or ECG and genistein as a control dose-dependently inhibited the growth of A549 cells, which strongly elevated hnRNP B1 protein, and increased G2/M phase cells associated with induction of apoptotic cells. The results were confirmed by previous evidence with human lung cancer cell line PC-9. Some larger differences in mechanisms of action between green tea polyphenols and genistein were presented. Treatment of A549 cells with EGCG, ECG or genistein significantly inhibited the expression levels of hnRNP B1 mRNA and the elevated levels of hnRNP B1 protein, both of which are constitutively elevated in cancer cells. Furthermore, both EGCG and genistein inhibited the promoter activity of hnRNP A2/B1 gene expression, with IC50 values 29 microM for EGCG and 66 microM for genistein, suggesting the interaction of EGCG or genistein with the transcriptional complex. Looking at our results here, and those of previously reported epidemiological studies with green tea, we discuss the steadily accumulating evidence that clinical trials with green tea extract would be an efficient means of lung cancer prevention.

Evaluation of Apoptotic Cells Induced by Ultraviolet Light B Radiation in Epidermal Sheets Stained by the TUNEL Technique

Two major components of epidermal cells, keratinocytes and Langerhans cells, are injured by ultraviolet light B radiation, resulting in sunburn cell (apoptotic cell) formation, impaired function, and a reduced number of Langerhans cells. Quantitative analysis of Langerhans cell damage is usually performed using epidermal sheets, whereas that of keratinocytes has been performed by counting the number of sunburn cells in vertical tissue sections. In this study we assessed the influences of ultraviolet light B radiation on epidermal cells by apoptotic cell formation, using murine epidermal sheets stained by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique. Ten to 75 mJ per cm2 of ultraviolet light B radiation induced apoptotic cells in abdominal skin of C3H mice. The cells were induced in 6 h after 50 mJ per cm2 of ultraviolet light B irradiation with the peak in number in 24 h, 18.8 +/- 5.0 per mm2 and 97.7 +/- 7.4 per mm2, respectively. One week later, the apoptotic cells were not visualized. As C3H/He, BALB/C, and C57BL/6 mice showed almost the same frequency of apoptosis in epidermal sheets from 50 mJ per cm2 ultraviolet light B-irradiated skin, the induction of the cells by ultraviolet light B radiation did not depend on the genetic trait of the mouse. Xeroderma pigmentosum type A gene-deficient mice, however, showed a greater induction of apoptotic cells (216.9 +/- 25.2 per mm2) by ultraviolet light B radiation than xeroderma pigmentosum type A wild-type mice (89.5 +/- 13.6 per mm2) and conventional mice. Pretreatment with a SPF 60 sunscreen agent was quite effective in reducing the induction of apoptotic cells. Using confocal laser scanning microscopy and double staining, 1.5 +/- 2.7% of apoptotic cells were Ia-positive cells in 24 h after 50 mJ per cm2 of ultraviolet light B radiation. Apoptotic Ia-positive cells were not observed 48 h after the radiation. On the other hand, no apoptotic dendritic epidermal T cells were observed in up to 75 mJ per cm2 of ultraviolet light B radiated skin. Thus, nearly all apoptotic cells were keratinocytes, and Langerhans cells and dendritic epidermal T cells appeared resistant to ultraviolet light B-induced apoptosis. Compared with the assessment in vertical tissue sections, the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique with epidermal sheets appeared to be a more physiologically relevant method for quantitative evaluation of apoptotic epidermal cells induced by ultraviolet light B radiation.

Apoptosis and Ki-67 Expression in Adenomyotic Lesions and in the Corresponding Eutopic Endometrium

In Brief Objective To examine biologic and proliferative properties of adenomyotic lesions and to determine whether adenomyotic lesions originate in the basal layer of the eutopic endometrium. Methods We examined eutopic and ectopic endometria from 23 patients with adenomyosis. To obtain evidence for the induction of programmed cell death, apoptotic cells were identified using a modified terminal deoxynucleotidyltransferase-biotin nick end-labeling method. To evaluate cell death repressor activity, bcl-2 gene expression was examined using immunohistochemical staining. As a proliferative marker, Ki-67 expression was also examined immunohistochemically. Results In the eutopic endometrium, apoptosis was most frequently observed in epithelial cells during mid- to late secretory phases, although it was rarely found during early proliferative through early secretory phases (P < .01). In contrast, bcl-2 gene expression inversely correlated with the appearance of apoptosis. A similar tendency was observed in stromal cells. In the ectopic endometrium of adenomyosis, endometrial dating revealed that secretory change was rare, even in the secretory phase, and that induction of apoptotic cells as well as bcl-2 gene expression showed no cyclic change. In stromal cells of the ectopic endometrium, apoptosis was more frequent than was seen in the eutopic endometrium, in all menstrual phases (P < .05). Ki-67 was constantly expressed in the glandular epithelium of the ectopic endometrium, irrespective of the menstrual phases, whereas in the secretory phase it was less expressed in the eutopic endometrium of functional and basal layers (P < .01). Conclusion The induction of apoptosis seems to be regulated by hormonal changes in the eutopic endometrium and has an inverse correlation with bcl-2 gene expression. The ectopic endometrium in adenomyosis is rarely influenced by hormonal change and has different biologic and proliferative properties than events observed in the eutopic endometrium findings, which strongly suggest that the adenomyotic lesion does not originate in the basal endometrium. Ectopic endometrium in adenomyotic lesions is influenced rarely by hormonal change and has different biologic and proliferative properties than these events in the eutopic endometrium.

Apoptosis and Ki-67 expression in adenomyotic lesions and in the corresponding eutopic endometrium

Objective: To examine biologic and proliferative properties of adenomyotic lesions and to determine whether adenomyotic lesions originate in the basal layer of the eutopic endometrium. Methods: We examined eutopic and ectopic endometria from 23 patients with adenomyosis. To obtain evidence for the induction of programmed cell death, apoptotic cells were identified using a modified terminal deoxynucleotidyltransferase-biotin nick end-labeling method. To evaluate cell death repressor activity, bcl-2 gene expression was examined using immunohistochemical staining. As a proliferative marker, Ki-67 expression was also examined immunohistochemically. Results: In the eutopic endometrium, apoptosis was most frequently observed in epithelial cells during mid- to late secretory phases, although it was rarely found during early proliferative through early secretory phases ( P < .01). In contrast, bcl-2 gene expression inversely correlated with the appearance of apoptosis. A similar tendency was observed in stromal cells. In the ectopic endometrium of adenomyosis, endometrial dating revealed that secretory change was rare, even in the secretory phase, and that induction of apoptotic cells as well as bcl-2 gene expression showed no cyclic change. In stromal cells of the ectopic endometrium, apoptosis was more frequent than was seen in the eutopic endometrium, in all menstrual phases ( P < .05). Ki-67 was constantly expressed in the glandular epithelium of the ectopic endometrium, irrespective of the menstrual phases, whereas in the secretory phase it was less expressed in the eutopic endometrium of functional and basal layers ( P < .01). Conclusion: The induction of apoptosis seems to be regulated by hormonal changes in the eutopic endometrium and has an inverse correlation with bcl-2 gene expression. The ectopic endometrium in adenomyosis is rarely influenced by hormonal change and has different biologic and proliferative properties than events observed in the eutopic endometrium findings, which strongly suggest that the adenomyotic lesion does not originate in the basal endometrium.

Inhibitory effects of ginsenoside Rh2 on tumor growth in nude mice bearing human ovarian cancer cells.

Ginsenoside Rh2 (Rh2), isolated from an ethanol extract of the processed root of Panax ginseng CA Meyer, inhibits the growth of B16 melanoma cells. This study was designed to evaluate the ability of Rh2 to inhibit growth of human ovarian cancer cells (HRA) in vitro and in nude mouse. Rh2 inhibited proliferations of various established human ovarian cancer cell lines in a dose‐dependent manner between 10 and 60 μM in vitro and induced apoptosis at around the IC50 dose. When HRA cells were inoculated s.c. into the right flank of nude mice, all mice formed a palpable tumor within 14 days. Although i.p. administration of Rh2 alone hardly inhibited the tumor growth, when Rh2 was combined with cis‐diamminedichloroplatinum(II) (CDDP) the tumor growth was significantly inhibited, compared to treatment with CDDP alone. When mice were treated p.o. with Rh2 daily (but not weekly), the tumor growth was significantly (P<0.01) inhibited, compared to CDDP treatment alone. When Rh2 was combined with CDDP, the degree of tumor growth retardation was not potentiated. The survival time was significantly (P<, we examined whether p.o. administration of Rh2 has a dose‐dependent inhibitory effect on the tumor growth. I.p. and weekly administration of CDDP had more potent antitumor activity in the order of 1 mg/kg, 2 mg/kg and 4 mg/kg, whereas p.o. and daily administration of Rh2 (0.4 to 1.6 mg/kg) not only had antitumor activity comparable to that of 4 mg/kg CDDP, but also resulted in a significant increase of the survival. Doses of Rh2 used in this study did not result in any adverse side‐effects as confirmed by monitoring hematocrit values and body weight, unlike 4 mg/kg CDDP, which had severe side‐effects. It is noteworthy that p.o. but not i.p. treatment with Rh2 resulted in induction of apoptotic cells in the tumor in addition to augmentation of the natural killer activity in spleen cells from tumor‐bearing nude mice. Thus, particularly in view of the toxicity of CDDP, Rh2 alone would seem to warrant further evaluation for treatment of recurrent or refractory ovarian tumor.