Knockout of caspase-7 gene improves the expression of recombinant protein in CHO cell line through the cell cycle arrest in G2/M phase

BACKGROUND: Chinese hamster ovary cell line has been used routinely as a bioproduction factory of numerous biopharmaceuticals. So far, various engineering strategies have been recruited to improve the production efficiency of this cell line such as apoptosis engineering. Previously, it is reported that the caspase-7 deficiency in CHO cells reduces the cell proliferation rate. But the effect of this reduction on the CHO cell productivity remained unclear. Hence, in the study at hand the effect of caspase-7 deficiency was assessed on the cell growth, viability and protein expression. In addition, the enzymatic activity of caspase-3 was investigated in the absence of caspase-7. RESULTS: Findings showed that in the absence of caspase-7, both cell growth and cell viability were decreased. Cell cycle analysis illustrated that the CHO knockout (CHO-KO) cells experienced a cell cycle arrest in G2/M phase. This cell cycle arrest resulted in a 1.7-fold increase in the expression of luciferase in CHO-KO cells compared to parenteral cells. Furthermore, in the apoptotic situation the enzymatic activity of caspase-3 in CHO-KO cells was approximately 3 times more than CHO-K1 cells. CONCLUSIONS: These findings represented that; however, caspase-7 deficiency reduces the cell proliferation rate but the resulted cell cycle arrest leads to the enhancement of recombinant protein expression. Moreover, increasing in the caspase-3 enzymatic activity compensates the absence of caspase-7 in the caspase cascade of apoptosis.

Caspase-7 deficiency in Chinese hamster ovary cells reduces cell proliferation and viability

BACKGROUND: Chinese hamster ovary (CHO) cells are the most commonly used mammalian host cell In the commercial-scale production of biopharmaceutical proteins. Modification of genes involved in apoptosis may improve the productivity of CHO cells. Executive caspases, including caspases 3 and 7, play critical roles in apoptosis. The effects of the ablation of the caspase 7 gene on proliferation and viability of CHO cells remains unknown. In this study, we applied clustered regularly interspaced short palindromic repeat (CRISPR/Cas9) to target caspase 7 gene of CHO K1 cell via all in one and homology targeted integration strategies. Consequently, the effect of caspase 7 deficiency on cell proliferation, viability, and apoptosis was studied by MTT assay and flow cytometry. RESULTS: Findings of gel electrophoresis, western blotting, and sequencing confirmed the caspase 7 gene silencing in CHO cells (CHO-KO). Proliferation assay revealed that caspase 7 deficiency in CHO cells resulted in the reduction of proliferation in various CHO-KO clones. Besides, the disruption of caspase 7 had negative effects on cell viability in exposure with NaBu which confirmed by MTT assay. Results of flow cytometry using Anexin V/PI demonstrated that Nabu treatment (11 mM) declined the percentage of live CHO-K1 and CHO-KO cells to 70.3% and 5.79%. These results verified that the CHO-K1 cells were more resistant to apoptosis than CHO-KO, however most of CHO-KO cells undergone early apoptosis (91.9%) which seems to be a fascinating finding. CONCLUSION: These results reveal that caspase 7 may be involved in the cell cycle progression of CHO cells. Furthermore, it seems that targeting caspase 7 is not the ideal route as it had previously been imagined within the prevention of apoptosis but the relation between caspase 7 deficiency, cell cycle arrest, and the occurrence of early apoptosis will require more investigation.

Tannic acid-induced apoptosis in FaDu hypopharyngeal squamous cell carcinoma

Tannic acid (TA) is a water-soluble polyphenol compound found in various herbal plants. We investigated the chemopreventive effects of TA on FaDu hypopharyngeal squamous carcinoma cells. In an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, TA showed dose-dependent cytotoxicity with a half maximal inhibitory concentration (IC50) of 50 µM. Cell cycle analysis and immunofluorescence imaging demonstrated that under low-dose (25 µM) treatment, FaDu cells were arrested in G2/M phase, and as the dose of TA was increased, apoptosis was induced with the increase of cell population at sub-G1 phase. The expressions of various cyclins, including cyclin D1 and cyclin-dependent kinases (CDK-1 and CDK-2), were down-regulated at low doses of TA, whereas apoptotic effectors such as cleaved caspase 3, cleaved caspase 7, and poly (ADP-ribose) polymerase (PARP) were expressed in a dose-dependent manner in Western blotting. In addition, TA-induced apoptosis of FaDu cells might be mediated by the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase pathway, with the upregulation of p-AKT/p-PKB (phosphorylated protein kinase B) and p-ERK. Overall, our data support the hypothesis that TA is a potential candidate agent for the treatment of hypopharyngeal cancer.

Cellular Effects of Troglitazone on YD15 Tongue Carcinoma Cells

An FDA approved drug for the treatment of type II diabetes, Troglitazone (TRO), a peroxisome proliferator–activated receptor gamma agonist, is withdrawn due to severe idiosyncratic hepatotoxicity. In the search for new applications of TRO, we investigated the cellular effects of TRO on YD15 tongue carcinoma cells. TRO suppressed the growth of YD15 cells in the MTT assay. The inhibition of cell growth was accompanied by the induction of cell cycle arrest at G₀/G₁ and apoptosis, which are confirmed by flow cytometry and western blotting. TRO also suppressed the expression of cell cycle proteins such as cyclin D1, cdk2, cdk4, cyclin B1, cdk1(or cdc2), cyclin E1 and cyclin A. The inhibition of cell cycle proteins was coincident with the up-regulation of p21(CIP1/WAF1) and p27(KIP1). In addition, TRO induces the activation of caspase-3 and caspase-7, as well as the cleavage of PARP. Further, TRO suppressed the expressions of Bcl-2 without affecting the expressions of Bad and Bax. Overall, our data supports that TRO induces cell cycle arrest and apoptosis on YD15 cells.

Apoptotic effect of cisplatin and cordycepin on OC3 human oral cancer cells / 中国结合医学杂志

<p><b>OBJECTIVE</b>To evaluate apoptotic effects of cisplatin and cordycepin as single agent or in combination with cytotoxicity in oral cancer cells.</p><p><b>METHODS</b>The influences of cisplatin (2.5 μg/mL) and/or cordycepin treatment (10 or 100 μmol/L) to human OC3 oral cancer cell line were investigated by morphological observation for cell death appearance, methylthiazoletetrazolium (MTT) assay for cell viability, flow cytometry assay for cell apoptosis, and Western blotting for apoptotic protein expressions.</p><p><b>RESULTS</b>Data demonstrated that co-administration of cisplatin (2.5 μg/mL) and cordycepin (10 or 100 μmol/L) resulted in the enhancement of OC3 cell apoptosis compared to cisplatin or cordycepin alone treatment (24 h), respectively (P <0.05). In flow cytometry assay, percentage of cells arrested at subG1 phase with co-treatment of cordycepin and cisplatin (30%) was significantly higher than cisplatin (5%) or cordycepin (12%) alone group (P <0.05), confirming a synergistically apoptotic effect of cordycepin and cisplatin. In cellular mechanism study, co-treatment of cordycepin and cisplatin induced more stress-activated protein kinase/Jun terminal kinase (JNK), the expressions of caspase-7, and the cleavage of poly ADP-ribose polymerase (PARP) as compared to cisplatin or cordycepin alone treatment (P <0.05).</p><p><b>CONCLUSION</b>Cisplatin and cordycepin possess synergistically apoptotic effect through the activation of JNK/caspase-7/PARP pathway in human OC3 oral cancer cell line.</p>

The synergistic effect of lidamycin and rituximab on human B cell lymphoma / 药学学报

This study aimed to investigate the synergistic effect of lidamycin (LDM) and rituximab on human B cell lymphoma Ramos cells. Cell proliferation was measured using MTS assay, cell apoptosis was analyzed by Annexin V-FITC/PI assay, the expression of apoptosis related proteins was analyzed by Western blotting, and the in vivo lymphoma inhibition was verified using BALB/c mice inoculated via tail vein using Ramos cells which stably expressed pEGFP-N1 plasmid. The results showed that, after the pretreatment with rituximab for 48 h, rituximab and LDM showed significantly synergistic effects on cell proliferation. Cells in combined treatment group had a higher apoptosis rate than that in LDM treatment group. Compared with the LDM treatment group, the expression of apoptosis-related proteins such as Cleaved caspase-3, Cleaved caspase-7, Cleaved caspase-9 and Cleaved PARP in combined treatment groups increased, and expression of cIAP-2 and Bcl-2 decreased. The result of in vivo experiment showed that, in the combined treatment group, the survival time of BALB/c mice was significantly longer than the mice in control group and LDM treatment group, and the degree of tumor accumulation and metastasis to lymph nodes and spleen was lower.

Apoptotic Effect of Co-treatment with Curcumin and Cisplatin on SCC25 Human Tongue Squamous Cell Carcinoma Cell Line

Curcumin is a widely used flavoring agent in food, and it has been reported to inhibit cell growth, to induce apoptosis, and to have antitumor activity in many cancers. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatment with curcumin and cisplatin on human tongue SCC25 cells. To investigate whether the co-treatment efficiently reduced the viability of the SCC25 cells compared with the two treatments separately, an MTT assay was conducted. The induction and the augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining, and an analysis of DNA hypoploidy. Western blot, MMP and immunofluorescence tests were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following the co-treatment. In this study, following the co-treatment with curcumin and cisplatin, the SCC25 cells showed several forms of apoptotic manifestation, such as nuclear condensation, DNA fragmentation, reduction of MMP, increased levels of Bax, decreased levels of Bcl-2, and decreased DNA content. In addition, they showed a release of cytochrome c into the cytosol, translocation of AIF and DFF40 (CAD) to the nuclei, and activation of caspase-7, caspase-3, PARP, and DFF45 (ICAD). In contrast, separate treatments of 5 microM of curcumin or 4 microg/ml of cisplatin, for 24 hours, did not induce apoptosis. Therefore, our data suggest that combination therapy with curcumin and cisplatin could be considered as a novel therapeutic strategy for human oral squamous cell carcinoma.

Knockdown of Bcl-xL Enhances Growth-Inhibiting and Apoptosis-Inducing Effects of Resveratrol and Clofarabine in Malignant Mesothelioma H-2452 Cells

Mcl-1 and Bcl-xL, key anti-apoptotic proteins of the Bcl-2 family, have attracted attention as important molecules in the cell survival and drug resistance. In this study, we investigated whether inhibition of Bcl-xL influences cell growth and apoptosis against simultaneous treatment of resveratrol and clofarabine in the human malignant mesothelioma H-2452 cells. Resveratrol and clofarabine decreased Mcl-1 protein levels but had little effect on Bcl-xL levels. In the presence of two compounds, any detectable change in the Mcl-1 mRNA levels was not observed in RT-PCR analysis, whereas pretreatment with the proteasome inhibitor MG132 led to its accumulation to levels far above basal levels. The knockdown of Bcl-xL inhibited cell proliferation with cell accumulation at G2/M phase and the appearance of sub-G0/G1 peak in DNA flow cytometric assay. The suppression of cell growth was accompanied by an increase in the caspase-3/7 activity with the resultant cleavages of procaspase-3 and its substrate poly (ADP-ribose) polymerase, and increased percentage of apoptotic propensities in annexin V binding assay. Collectively, our data represent that the efficacy of resveratrol and clofarabine for apoptosis induction was substantially enhanced by Bcl-xL-lowering strategy in which the simultaneous targeting of Mcl-1 and Bcl-xL could be a more effective strategy for treating malignant mesothelioma.

Mechanism Underlying Curcumin-induced Apoptosis and Cell Cycle Arrest on SCC25 Human Tongue Squamous Cell Carcinoma Cell Line

Several studies have shown that curcumin, which is derived from the rhizomes of turmeric, possesses antimicrobial, antioxidant and anti-inflammatory properties. The antitumor properties of curcumin have also now been demonstrated more recently in different cancers. This study was undertaken to investigate the modulation of cell cycle-related proteins and the mechanisms underlying apoptosis induction by curcumin in the SCC25 human tongue squamous cell carcinoma cell line. Curcumin treatment of the SCC25 cells resulted in a time- and dose-dependent reduction in cell viability and cell growth, and onset of apoptotic cell death. The curcumin-treated SCC25 cells showed several types of apoptotic manifestations, such as nuclear condensation, DNA fragmentation, reduced MMP and proteasome activity, and a decreased DNA content. In addition, the treated SCC25 cells showed a release of cytochrome c into the cytosol, translocation of AIF and DFF40/CAD into the nuclei, a significant shift in the Bax/Bcl-2 ratio, and the activation of caspase-9, caspase-7, caspase-6, caspase-3, PARP, lamin A/C, and DFF45/ICAD. Furthermore, curcumin exposure resulted in a downregulation of G1 cell cycle-related proteins and upregulation of p27KIP1. Taken together, our findings demonstrate that curcumin strongly inhibits cell proliferation by modulating the expression of G1 cell cycle-related proteins and inducing apoptosis via proteasomal, mitochondrial, and caspase cascades in SCC25 cells.

Inhibition of Jumi extraction on growth of human cervical cancer cell line HeLa / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the inhibition of Jumi (traditional Chinese medicine) extraction on the growth of human cervical cancer cell line HeLa.</p><p><b>METHODS</b>Nude mouse model of human cervical cancer HeLa cell transplantation was established. The nude mice bearing cancer were randomly divided into control group and Jumi treated groups with different concentration (0.001, 0.002, 0.005, 0.01 mg/ml). The growth of cervical cancer cell in experimental mice were measured. Cultured HeLa cells were incubated in culture media with or without Jumi extract for 48 hours. Cell proliferation rate, cell apoptosis, caspase-3/7 and caspase-6 activity were determined by MTT colorimetric assay, flow cytometry analysis and spectrophotometric detection, respectively.</p><p><b>RESULTS</b>With the increase of the concentration of Jumi extract, tumor-bearing mice tumor inhibition rate gradually increased. The proliferation of cultured HeLa cells were significantly inhibited by Jumi extract in a dose-dependent manner. IC50 was 0.004 mg/ml. Apoptosis rates in the cells treated with Jumi extract were higher than those of the control group. Compared with the control group, except for lower Jumi treated group (0.001 mg/ml), caspase-3/7 and caspase-6 activity were significantly increased in the all Jumi treated groups.</p><p><b>CONCLUSION</b>Jumi extract can inhibit the proliferation of human cervical cancer cell line HeLa in vitro in a dose-dependent manner and promote cell apoptosis through caspase-3, caspase-7 and caspase-6 pathway.</p>

Apoptotic Effects of Co-Treatment with a Chios Gum Mastic and Eugenol on G361 Human Melanoma Cells

We investigated the synergistic apoptotic effects of co-treatments with Chios gum mastic (CGM) and eugenol on G361 human melanoma cells. An MTT assay was conducted to investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining, and analyses of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate expression and translocation of apoptosis-related proteins following CGM and eugenol co-treatment. Proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed.The results indicated that the co-treatment of CGM and eugenol induces multiple pathways and processes associated with an apoptotic response in G361 cells. These include nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, an increase of Bax and decrease of Bcl-2, a decreased DNA content, cytochrome c release into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of 40 microg/ml CGM or 300 microM eugenol for 24 hours did not induce apoptosis. Our present data thus suggest that a combination therapy of CGM and eugenol is a potential treatment strategy for human melanoma.

Effects of hydroquinone on retinal and vascular cells in vitro.

Aim: To explore the molecular pathophysiology that might explain the epidemiologic association between cigarette smoke and age-related macular degeneration (AMD) by examining the effects of hydroquinone (HQ), a toxic compound present in high concentration in cigarette smoke-related tar, on human retinal pigment epithelial cells (ARPE-19), rat retinal neurosensory cells (R-28), and human microvascular endothelial cells (HMVEC). Materials and Methods: ARPE-19, R-28, and HMVEC were treated for 24 h with four different concentrations of HQ (500 μM, 200 μM, 100 μM, 50 μM). Cell viability, caspase-3/7 activation, DNA laddering patterns, and lactate dehydrogenase (LDH) levels were analyzed. Results: At 50 μM HQ, R-28 cells showed a significant decrease in cell viability compared with the dimethyl sulfoxide (DMSO)-treated controls. At the 100–500 μM concentrations, all three cell lines showed significant cell death (P < 0.001). In the ARPE-19, R-28, and HMVEC cultures, the caspase-3/7 activities were not increased at any of the HQ concentration. Conclusion: Our findings suggest that the mechanism of cell death in all three cell lines was through non-apoptotic pathway. In addition, neuroretinal R-28 cells were more sensitive to HQ than the ARPE-19 and HMVEC cultures.

Mechanism of hepatocyte apoptosis in rats with liver fibrosis induced by lipogenic methionine-choline-deficient diet / 中华病理学杂志

<p><b>OBJECTIVE</b>To clarify the effects of endoplasmic reticulum stress (ER stress) and mitogen-activated protein kinase (MAPK) on hepatocyte apoptosis in rats with non-alcoholic fatty liver fibrosis induced by methionine-choline-deficient diet (MCDD).</p><p><b>METHODS</b>Nonalcoholic steatohepatitis with advanced fibrosis was induced in rats by giving a MCDD for 10 weeks (group M). A methionine-choline-control diet (MCCD) instead of MCDD was given for the last 2 weeks to the experimental group (group R). Steatosis, fibrosis and inflammation were determined by tissue staining. The activation of hepatic stellate cells and oxidative stress were determined by immunostaining, immunoblotting or real time-PCR (RT-PCR), respectively. Hepatocyte apoptosis was determined by TUNEL staining. Expressions of glucose-regulated protein 78 (GRP78), caspase-12, caspase-7, cleaved caspase-7, caspase-3, cleaved caspase-3, and caspase-9 were evaluated to clarify the presence of ER stress. Expressions of c-Jun, ERK1/2, p-ERK1/2 were evaluated to clarify the states of MAPK signaling.</p><p><b>RESULTS</b>Changing the diet from MCDD to MCCD triggered the reduction of fat in hepatocytes, a decrease in inflammatory response, oxidative stress, and fibrosis. The protein expressions of ERP78, caspase-12, caspase-7, and cleaved caspase-7 were increased significantly in group M compared with normal control group (group N, P < 0.05 or P < 0.01), the mRNA expressions of ERP78, caspase-12, and caspase-7 were also increased significantly in group M compared with group N (3.03 ± 0.41 vs 2.12 ± 0.37, 1.86 ± 0.36 vs 0.78 ± 0.20, and 2.38 ± 0.19 vs 1.84 ± 0.13, respectively, P < 0.05 or P < 0.01), while they recovered immediately in group R. In contrast, the protein levels of caspase-3, cleaved caspase-3 and mRNA expressions of caspase-3 and caspase-9 revealed no significant differences in three groups (P > 0.05). The mRNA expressions of c-Jun and protein levels of ERK1 and p-ERK1 were increased significantly in group M compared with group N (P < 0.01), while they recovered immediately after changing the diet from MCDD to MCCD.</p><p><b>CONCLUSIONS</b>ER stress plays a role in the development and regression of non-alcoholic fatty liver fibrosis induced by MCDD, however, ER stress-related caspase-12 pathway may not be the main mechanism of hepatic apoptosis, and MAPK signaling may play an important role in hepatic apoptosis in the model.</p>

11'-Deoxyverticillin A induces caspase-dependent cell apoptosis in PC3M cells / 生物工程学报

Recent years, the incidence and mortality of prostate cancer have increased dramatically in China. At earlier stages, most diagnosed prostate cancers are responsive to androgen depletion treatment, yet, nearly all patients will eventually progress to metastatic androgen-independent prostate cancer (AIPC), which still has no effective therapeutic method or drug to deal with. 11'-Deoxyverticillin A (C42) belongs to the family of epipolythiodioxopiperazines (ETPs), an interesting class of fungal toxins that inhibit farnesyl transferase. Compounds holding such a property have been explored as putative anticancer agents. In this study, using PC3M cells, an AIPC cell line, we investigated the effect of the compound on apoptosis and explored the underlying mechanism. It revealed that C42 markedly enhanced the activity of caspase-3/7 and increased the accumulation of the cleaved PARP, all of which are the markers of apoptosis. It also revealed that C42 either decreased cell viability or inhibited the growth of PC3M cells. Moreover, we observed that the loss of cell viability and cell growth inhibition induced by C42 were both time- and dosage dependent. Taken together, we indicated that C42 can induce caspase-dependent apoptosis in AIPC cells, and the results presented here will broaden our knowledge about the molecular mechanisms by which C42 exerts its anticancer activity, and future work in this direction may provide valuable information in the development of these compounds into effective cancer therapeutic strategies against androgen-independent prostate cancer.

Role of NF-κB in factor VIIa-induced proliferation and migration of colon cancer cell line SW620 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the roles of NF-κB in factor VIIa-induced proliferation and migration of a colon cancer cell line (SW620) in vitro and its possible mechanism.</p><p><b>METHODS</b>The expression levels of NF-κB (p65), inhibitory protein of NF-κB (IκB-α), caspase-7, interleukin 8 (IL-8) and tissue factor (TF) in SW620 cells treated with factor VIIa, PDTC (an inhibitor of NF-κB) and other factors were measured by Western-blotting and real-time PCR. Proliferation and migration of the cells were analyzed by flow cytometry and Transwell assay, respectively.</p><p><b>RESULTS</b>Factor VIIa down-regulated the IκB-α level in SW620 cells and increased the intranuclear level of NF-κB. Those effects of factor VIIa were blocked by anti-TF or anti-PAR2 antibodies. The effects of factor VIIa on proliferation and migration of SW620 cells, expression of IL-8, TF as well as caspase-7, were interfered by PDTC (the inhibitor of NF-κB).</p><p><b>CONCLUSIONS</b>TF/VIIa complex activates NF-κB pathway via PAR2, thereby up-regulates IL-8 and down-regulates caspase-7 expression in SW620 cells, finally promotes proliferation and migration of colon cancer cells. In addition, TF/VIIa/PAR2/NF-κB pathway also upregulates TF expression, thus to create a positive feedback loop of TF/VIIa/PAR2/NF-κB/TF.</p>

Apoptotic Effects of A Cisplatin and Eugenol Co-treatment of G361 Human Melanoma Cells

Eugenol (4-allyl-2-methoxyphenol) is a naturally occurring phenolic compound that is widely used in dentistry as a component of zinc oxide eugenol cement that is commonly applied to the mouth environment. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatments with eugenol and cisplatin on human melanoma (G361) cells. To investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment, an MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed. The results indicated that a co-treatment with eugenol and cisplatin induced multiple pathways and processes associated with an apoptotic response in G361 cells including nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, the increase and decrease of Bax and Bcl-2, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of 300 microM eugenol or 3 microM cisplatin for 24 h did not induce apoptosis. Our present data thus suggest that a combination therapy of eugenol and cisplatin is a potential treatment strategy for human melanoma.

Mechanism Underlying NaF-induced Apoptosis and Cell Cycle Arrest on G361 Human Melanoma Cell Line / 체질인류학회지

Fluoride is widely used in dentistry to prevent dental caries, even though the safety of fluoride is a controversial issue. There are no known adverse effects of long-term fluoride ingestion for caries prevention, but an overdose can cause serious acute toxicity. Nevertheless it is accepted that fluoride is an important material for oral health. This study was undertaken to investigate the modulation of cell cycle-related proteins and apoptosis induction underlying mechanism by NaF treatment on G361 human melanoma cell line. The viability of G361 cells and the growth inhibition of G361 cells were assessed by MTT assay and clonogenic assay respectively. Hoechst staining, DNA electrophoresis and TUNEL staining were conducted to observe G361 cells undergoing apoptosis. G361 cells were treated with NaF, and Western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, MMP activity and proteasome activity were performed. NaF treatment in G361 cells resulted in a time- and does-dependent decrease of cell viability and a does-dependent inhibition of cell growth, and induced apoptotic cell death. And tested G361 cells showed several lines of apoptotic manifestation such as nuclear condensation, DNA fragmentation, the reduction of MMP and proteasome activity, the decrease of DNA contents, the release of cytochrome c into cytosol, the translocation of AIF and DFF40 (CAD) onto nuclei, a significant shift of Bax/Bcl-2 ratio, and the activation of caspase-9, caspase-7, caspase-6, caspase-3, PARP, Lamin A/C and DFF45 (ICAD). Furthermore, NaF resulted in down-regulation of the G1 cell cycle-related proteins, and up-regulation of p53. Taken collectively, our present findings demonstrate that NaF strongly inhibits cell proliferation by modulating the expression of the G1 cell cycle-related proteins and induces apoptosis via proteasome, mitochondria and caspase cascades in G361 cells.

Ethanol Extracts of Angelica decursiva Induces Apoptosis in Human Oral Cancer Cells

Angelica decursiva has been used in Korean traditional medicine as an antitussive, an analgesic, an antipyretic and a cough remedy. However, its anti-cancer properties have not yet been well defined. In our current study, we report the cytotoxic activity and the mechanism of cell death induced by ethanol extracts of Angelica decursiva (EEAD) against the human oral cancer cell line, KB. Treatment of KB cells with EEAD induced apoptotic cell death in both a dose- and time-dependent manner as determined by MTT assay and DNA fragmentation. However, no cytotoxic effects of EEAD against human normal oral keratinocytes (HNOK) were evident. By western blot analysis, we found that apoptosis in KB cells is associated with a decrease in procaspase-7 and -9. In addition, the activation of caspase-7 was detectable in living KB cells by fluorescence microscopy. These results suggest that EEAD exhibits anti-cancer activity in KB cells via apoptosis and thus has potential as an anticancer agent in future drug development strategies.

Investigation of the mechanisms of coagulation factor VIIa-induced colon cancer SW620 cell proliferation and migration / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms that coagulation factor VIIa promotes proliferation and migration of a colon cancer cell line (SW620 cells) in vitro.</p><p><b>METHODS</b>The expression of interleukin 8 (IL-8), tissue factor (TF), caspase-7 and p-p38 MAPK in SW620 cells treated with factor VIIa or protease activated receptor 2 agonist (PAR2-AP) was measured by ELISA, Western-blotting and QT-PCR.</p><p><b>RESULTS</b>Factor VIIa and PAR2-AP induced IL-8 expression at both mRNA and protein levels, upregulated TF mRNA expression and TF activity, but down-regulated caspase-7 mRNA and p-p38 MAPK levels in SW620 cells. The effects of factor VIIa were not only blocked by anti-TF but also by anti-PAR2 antibodies.</p><p><b>CONCLUSION</b>Factor VIIa binds to TF on cell surface, forming a complex which activates PAR2, then provoking IL-8 and TF expression, and suppresses caspase-7 expression, thus promotes the tumor cell proliferation and migration. p38 MAPK may negatively regulate this process.</p>

Induction of G2 /M phase arrest and apoptosis of MCF-7 cells by novel benzofuran lignan via suppressing cell cycle proteins / 药学学报

In the present study, a newly synthesized benzofuran lignan 4-formyl-2-(4-hydroxy-3methoxyphenyl)-5-(2-methoxycarbonyethyl)-7-methoxy-benzo [b] furan (ERJT-12) was tested for its antiproliferative activity on human tumor cells. The related mechanisms were also investigated. In vitro growth inhibitory effects of ERJT-12 on various cancer cell lines were determined by MTT assay. Cell cycle distribution and apoptosis were detected by flow cytometry. The integrity of DNA was assessed by agarose gel electrophoresis. Activation of Caspase-3/7 and Caspase-6 was measured by colorimetric assay. The expressions of cell cycle proteins cell divide cycle 25c (Cdc25c), cyclin dependent kinase 1 (CDK1), CyclinB1 and apoptosis-related proteins Bax and Bcl-2 were detected by Western blotting. MTT assay showed that ERJT-12 inhibited the proliferation of several cancer cell lines including multidrug resistant cells. MCF-7 cells were markedly arrested at gap2/mitosis (G2/M) phase after treatment with ERJT-12 and progressed into apoptosis. The increased activities of Caspase-3/7 and Caspase-6 in MCF-7 cells were observed. The expression of CyclinB1 was down-regulated. The activities of Cdc25c and CDK1 protein were suppressed and Bcl-2 protein was phosphorylated. ERJT-12 displays potent antiproliferative activity towards cancer cells through suppressing cell cycle proteins, arresting cell cycle at G2/M phase and inducing apoptosis. It might be a novel candidate for cancer therapy.