Differential Suppression of Human Cervical Cancer Cell Growth by Adenovirus Delivery of p53 in vitro: Arrest Phase of Cell Cycle Is Dependent on Cell Line

It has been reported that overexpression of wild-type p53 protein induces suppression of tumor cell growth in vivo and in vitro. In this study, we further evaluated the differential effects of p53 delivered in an adenovirus vector on the cell growth, apoptosis and cell cycle progression in cervical cancer cell lines. We constructed a recombinant adenovirus expressing p53 and then delivered this into cervical carcinoma cell lines (CaSki, SiHa, and HeLa, HeLaS3) along with adenovirus expressing β-galactosidase as a negative control. Adenovirus-delivered p53 overexpression resulted in a more significant suppression of cell growth in HPV 18-infected cells (HeLa and HeLaS3) and a lesser suppression in HPV 16-infected cells (CaSki and SiHa). However, no suppression was observed in cells infected with a negative control virus. p53 overexpression also induced apoptosis and cell cycle arrest, as determined by annexin V and propidium iodide staining. In particular, the cell cycle was arrested in the G₂/M phase in CaSki cells. In contrast, cell cycles were arrested in the G₁ phase in HeLa cells, suggesting that the arrest phase is dependent upon the cervical cancer cell line. Taken together, these data support the idea that overexpressed p53 protein plays a differential role in suppressing cervical cancer cell growth through apoptosis and cell cycle arrest in either G₁ or G₂/M phase, depending on the cancer cell line.     

TRICHOSTATIN A INHIBITS PROLIFERATION, INDUCES APOPTOSIS AND CELL CYCLE ARREST IN HELA CELLS

Objective： The histone deacetylase inhibitors （HDACIS） have been shown to inhibit cancer cell proliferation, stimulate apoptosis, an induce cell cycle arrest. Our purpose was to investigate the antiproliferative effects of a HDACI, trichostatin A （TSA）, against human cervical cancer cells （HeLa）. Methods： HeLa cells were treated in vitro with various concentrations of TSA. The inhibitory effect of TSA on the growth of HeLa cells was measured by MTT assay. To detect the characteristic of apoptosis chromatin condensation, HeLa cells were stained with Hoechst 33258 in the presence of TSA. Induction of cell cycle arrest was studied by flow cytometry. Changes in gene expression of p53, p21wafl and p27Kipl were studied by semiquantitative RT-PCR. Results： TSA inhibited cell growth in a time- and dose-dependent manner. Hoechst 33258 staining assay showed that TSA induced apoptosis. Cell cycle analysis indicated that treatment with TSA decreased the proportion of cells in S phase and increased the proportion of cells in G0/G1 and/or G2/M phases of the cell cycle. This was concomitant with overexpression of genes related to malignant phenotype, including an increase in p53, p21wall and p27Kipl. Conclusion： These results suggest that TSA is effective in inhibiting growth of HeLa cells in vitro. The findings raise the possibility that TSA may prove particularly effective in treatment of cervical cancers.     

Changes in p21WAF1, pRb, Mdm-2, Bax and Bcl-2 expression in cervical cancer cell lines transfected with a p53 expressing adenovirus

The aim of this study was to provide some insights into the molecular mechanisms involved in p53-dependent apoptosis and growth arrest. Changes in the levels of p53 protein and proteins regulated by p53 were studied in relation to events of the cell cycle and apoptosis in cervical cancer cell lines upon transfection with a p53 expressing adenovirus (Ad5-p53). The post-transfection level of p53 protein in SiHa cells was found to be unchanged during the 24-48 h period. In contrast, the level of p21WAF1 protein was shown to increase to its highest level at 24 h, and decreased gradually up to 48 h after the Ad5-p53 transfection. We further noted that the increase of p21WAF1 was accompanied by G1 arrest at 24 h and the decrease of p21WAF1 was associated with apoptosis at 36-48 h after transfection. An anti-p21WAF1 antibody cross-reactive protein band of approximately 14 kDa was observed in HeLa and C-33A cells when these cells were committed to apoptosis upon Ad5-p53 transfection. In SiHa cells, phosphorylation of pRb was inhibited during the early stage of Ad5-p53 transfection. This was followed by the cleavage of pRb. However, Ad5-p53 transfection did not change the levels of Bax and Bcl-2 proteins. Our results suggested that, Bax and Bcl-2 may not be important for the apoptosis of these cells, whereas cleavage of Rb, and the decrease of p21WAF1 could play important roles in p53-dependent apoptosis.     

Efficient growth inhibition of HPV 16 E6-expressing cells by an adenovirus-expressing p53 homologue p73beta

Tumor suppressor p53 functions are downregulated in most cervical cancers, because the product of human papilloma virus (HPV) oncogene E6 binds to and inactivates p53 by promoting its degradation. p73, a p53 homologue, is similar to p53 in structure and function but yet not degraded by HPV E6 gene product. In this study, we have developed a replication-deficient recombinant adenovirus, which expresses p73beta (Ad-p73). Infection of human cancer cells with Ad-p73 results in several fold increase of p73beta levels as well as its known target genes like p21(WAF1/CIP1). Ad-p73-infected cells showed reduced cellular DNA synthesis, arrest in G1 phase of cell cycle and induction of apoptosis. Ad-p73 inhibited the growth of cancer cells of different types. More importantly, Ad-p73 inhibited the growth of cell lines carrying HPV E6 gene, which was introduced by stable integration, more efficiently in comparison to an Ad-p53. Furthermore, Ad-p73 also inhibited the growth of HeLa cells, a cell line derived from cervical cancer, very efficiently. The ability of Ad-p73 to inhibit the growth of HPV E6-expressing cells and HeLa cells correlated with the stable expression of functional p73 in the presence of E6. These results suggest that Ad-p73 could be used as a potential gene therapy agent against cervical cancer.     

Anticancer Activity of Solvent Extracts of Hexogonia glabra against Cervical Cancer Cell Lines

Objective: In this study, we aimed to harness some solvent extracts of one wild mushroom Hexagonia glabra and test their anti-cancer activity against cervical human cell lines, namelyHeLa, SiHa, and CaSki. Methods: It includes cell morphological study by microscope, nuclear morphology by DAPI staining under fluorescence microscopy, apoptosis assay by fluorescence technique, anti-proliferation by MTT assay and expression of apoptotic and anti-apoptotic genes by Western blotting and cell cycle analysis was done. Results: The selected cervical cancer cells were treated separately with 150 µg/mL of three extracts, namely of ethanolic (EE), ethyl acetate (EAE), and water extract (WE) and exhibited features like round, shrink and dead. All extracts caused apoptosis in cell lines and EE had the highest effect in this regard. The percentages of apoptotic cells in HeLa, SiHa and CaSki, at the same concentration of EE were 79.23, 75.42, and 76.36% respectively. Cytotoxicity assay showed that all three extracts (50 – 250 μg/mL) were potent for inhibition of cell growth of three cell lines and again EE had the highest effect. The percentages of cell growth inhibition in HeLa, SiHa, and CaSki cells treated with EE at 24 h at 50 µg/mL were 45.79±4.11, 41.66±4.03, and 36.72±2.67, while they were 74.23±7.45, 62.31±5.97, and 54.23±5.04 at 150 µg/mL concentration. At 250 µg/mL concentration, the percentages of cell growth inhibition were 94.25 ±8.11, 90.02 ±8.67, and 85.43±6.21, respectively. The expression of apoptotic gene (Caspase 3, 9) and tumor guard gene (p53), as their proteins in Western blotting increased . However, anti-apoptotic BcL2 gene of all cell lines was decreased following treatment with extracts. In addition, the cell cycle analysis (CaSki cell) showed that treatment (EE) arrested at G2/M check point cell cycle. Conclusion: All extracts of this mushroom were active in arresting growth of three cell lines and EE had the highest effect, indicating that this mushroom can be a valuable source of anticancer agents.     

Methyl jasmonate induces cell death with mixed characteristics of apoptosis and necrosis in cervical cancer cells

In the present study the effectiveness of methyl jasmonate (MJ) against cervical cancer cell lines was investigated. We show that MJ is cytotoxic to a range of cervical cancer lines including SiHa, CaSki and HeLa that carry human papillomavirus (HPV) DNA and wild type p53, and C33A that is negative for HPV and contains mutant p53. Primary human foreskin keratinocytes were almost resistant to the drug. Cytotoxicity of MJ was dose and time dependent, and associated mainly with the induction of cell death and to a less extent with inhibition of cell growth. Cell death induced by MJ displayed features characteristic to both apoptosis and necrosis, and was associated with different changes in the levels of p53, p21, bcl-2 and bax in the various cervical cancer lines. In conclusion, MJ a novel anticancer agent, acts via multiple pathways to induce death of cervical cancer cells, thus making it a promising candidate for treatment of cervical cancer.     

Diallyl sulfide induces cell cycle arrest and apoptosis in HeLa human cervical cancer cells through the p53, caspase- and mitochondria-dependent pathways

Diallyl sulfide (DAS), one of the main active constituents of garlic, causes growth inhibition of cancer cells in vitro and promotes immune responses in vivo in experimental settings. However, its effects on the induction of cell cycle and apoptosis in human cervical cancer cells are still unclear. The aims of this study were to explore the anti-cancer effects of DAS in HeLa human cervical cancer cells and to investigate the underlying mechanisms in vitro. Cytotoxicity and apoptosis in HeLa human cervical cancer cells were examined by the morphological changes, viability assay, 4',6-Diamidino-2-phenylindole dihydrochloride (DAPI) staining, comet assay, Western blotting and confocal microscopy examination. The results showed that DAS treatment for 24-72 h resulted in a marked decrease in cell viability time- and dose-dependently. Flow cytometric analysis showed that a 48-h treatment of 75 μM DAS induced G0/G1 cell cycle arrest and sub-G1 phase (apoptosis) in HeLa cells. Typical apoptotic nucleus alterations were observed by fluorescence microscopy in HeLa cells after exposure to DAS using DAPI staining. Cells treated with different concentrations of DAS also showed changes typical of apoptosis such as morphological changes, DNA damage and fragmentation, dysfunction of mitochondria, cytochrome c release and increased expression of pro-caspase-3 and -9. DAS also promoted the release of AIF and Endo G from mitochondria in HeLa cells. In conclusion, DAS induced G0/G1 cell cycle arrest and apoptosis in HeLa cells through caspase- and mitochondria and p53 pathways providing further understanding of the molecular mechanisms of DAS action in cervical cancer. This study, therefore, revealed that DAS significantly inhibits the growth and induces apoptosis of human cervical cancer HeLa cells in vitro.     

Proteasome inhibitor MG132 sensitizes HPV-positive human cervical cancer cells to rhTRAIL-induced apoptosis

In cervical carcinogenesis, the p53 tumor suppressor pathway is disrupted by HPV (human papilloma virus) E6 oncogene expression. E6 targets p53 for rapid proteasome-mediated degradation. We therefore investigated whether proteasome inhibition by MG132 could restore wild-type p53 levels and sensitize HPV-positive cervical cancer cell lines to apoptotic stimuli such as rhTRAIL (recombinant human TNF-related apoptosis inducing ligand). In a panel of cervical cancer cell lines, CaSki was highly, HeLa intermediate and SiHa not sensitive to rhTRAIL-induced apoptosis. MG132 strongly sensitized HeLa and SiHa to rhTRAIL-induced apoptosis in a caspase-dependent and time-dependent manner. MG132 massively induced TRAIL receptor DR4 and DR5 membrane expression in HeLa, whereas in SiHa only DR5 membrane expression was upregulated from almost undetectable to high levels. Antagonistic DR4 antibody partially inhibited apoptosis induction by rhTRAIL and MG132 in HeLa but had no effect on apoptosis in SiHa. Inhibition of E6-mediated p53 proteasomal degradation by MG132 resulted in elevated levels of active p53 as demonstrated by p53 small interfering RNA (siRNA) sensitive p21 upregulation. Although p53 siRNA partially inhibited MG132-induced DR5 upregulation in HeLa and SiHa, no effect on rhTRAIL-induced apoptosis was observed. MG132 plus rhTRAIL enhanced caspase 8 and caspase 3 activation and concomitant cleavage of X-linked inhibitor of apoptosis (XIAP), particularly in HeLa. In addition, caspase 9 activation was only observed in HeLa. Downregulation of XIAP using siRNA in combination with rhTRAIL induced high levels of apoptosis in HeLa, whereas MG132 had to be added to the combination of XIAP siRNA plus rhTRAIL to induce apoptosis in SiHa. In conclusion, proteasome inhibition sensitized HPV-positive cervical cancer cell lines to rhTRAIL independent of p53. Our results indicate that not only DR4 and DR5 upregulation but also XIAP inactivation contribute to rhTRAIL sensitization by MG132 in cervical cancer cell lines. Combining proteasome inhibitors with rhTRAIL may be therapeutically useful in cervical cancer treatment.     

Hydralazine inhibits human cervical cancer cell growth in vitro in association with APC demethylation and re-expression

Purpose  The tumor suppressor adenomatous polyposis coli (APC) is frequently silenced by promoter hypermethylation in human cervical cancer. Clinically, it has been approved that DNA methylation inhibitors, such as 5-aza-2′-deoxycytidine (5-Aza-dC), can reverse APC promoter methylation, but widespread clinical use of these inhibitors is limited by their toxicity and instability in aqueous solution. Hydralazine is a stable DNA methylation inhibitor that has minimal toxicity in vitro and in vivo. The purpose of this study was to evaluate the effects of hydralazine on APC reactivation and the inhibition of human cervical cancer cells in vitro. Methods  Expression of APC gene, and methylation status were analyzed by RT-PCR, quantitative real time RT-PCR, and methylation-specific PCR methods. β-Catenin protein that correlates closely with APC was detected by immunohistochemistry method after treatment with hydralazine. MTT and FCM assays were used to observe the changes of proliferation activity, cell cycle, and apoptosis of the cells. Results  Methylated APC was not expressed in HeLa cell, hemimethylated APC was expressed in CaSki cells, and unmethylated APC was expressed normally in SiHa cells. Hydralazine induces APC expression and promotes demethylation in HeLa and CaSki cells. After treatment with 40 μmol/L hydralazine for 72 h, growth inhibitive rates (%) of HeLa, CaSki, and SiHa cell lines were 52.12 ± 3.78, 44.31 ± 2.59, and 47.73 ± 4.73, respectively. On the contrary, the normal cell ECV304 growth inhibitory rate was only 27.18 ± 0.79. The expression of APC mRNA in HeLa, CaSki, and SiHa cell lines increased 10.35-, 11.40-, and 0.73-fold, respectively. HeLa and CaSki cells were arrested in S phase of the cell cycle by hydralazine, and the percentage of apoptotic cells in the two cell lines treated with hydralazine was increased significantly compared to the untreated cells (P < 0.01). The expression of β-catenin protein in the cell membrane was observed after the treatment with hydralazine. Conclusions  Hydralazine, an effective inhibitor of APC methylation and promoter of APC re-expression, can inhibit cell growth in human cervical cancer in vitro and be potentially used for the clinical treatment of human cervical cancer.     

pRb-expressing adenovirus Ad5-Rb attenuates the p53-induced apoptosis in cervical cancer cell lines

The retinoblastoma protein (pRb), the gene product of the first reported tumour suppressor gene, is functionally inactivated by the E7 protein of high-risk human papillomavirus (HPV) found in most human cervical cancers. We have, in this study, constructed an adenoviral vector expressing wild-type pRb (Ad5-Rb) and used the constructed Ad5-Rb to transfect the osteosarcoma cell line Saos-2, and three cervical cancer cell lines HeLa, SiHa and C-33A. Our results showed that pRb caused G1 arrest in Saos-2 cells after transfection with Ad5-Rb. The number of colonies formed by the Ad5-Rb-transfected Saos-2 cells in soft agar was also found to be significantly lower (P<0.05) than those transfected with the adenoviral control expressing Escherichia coli β-galactosidase (Ad5-LacZ). The transfection of Ad5-Rb caused an increase in the population of SiHa and C-33A cells in the G1 phase from 53.0 and 52.9% to 72.4 and 64.3%, respectively, but not in the HeLa cells. However, Ad5-Rb did not show any inhibitory effect on the growth of SiHa, HeLa and C-33A cells, and inhibition of colony formation in soft agar was not observed either. In contrast, flow cytometric analysis showed that Ad5-p53, a p53-expressing adenovirus, induced apoptosis, i.e. the appearance of sub-G1 peak, in all three tested cervical cancer cell lines. Nevertheless, the Ad5-p53-induced apoptosis was partially inhibited when Ad5-Rb was added simultaneously. These findings suggested that pRb may not be a good candidate for cervical cancer gene therapy. Our data also showed that the use of full-length pRb in combination with TP53 might not be a suitable strategy for cancer gene therapy.     

miRNA-34a过表达对4种人宫颈癌细胞放射敏感性研究

目的 研究miRNA-34a过表达对4种人宫颈癌细胞放射敏感性的影响。方法 运用脂质体2000转染试剂盒将pGenesil-1-miRNA-34a表达质粒转染宫颈癌细胞系C33A、HeLa、SiHa和CaSki,通过G418筛选构建过表达miRNA-34a宫颈癌细胞系(miRNA-34a/C33A、miRNA-34a/HeLa、miRNA-34a/SiHa和miRNA-34a/CaSki)。细胞经不同剂量⁶⁰Coγ射线照射;运用TaqManRT-PCR和蛋白印迹法测定细胞中miRNA-34a表达;运用MTT法和克隆形成实验分别测定细胞增殖抑制率和克隆形成能力,流式细胞仪测定细胞凋亡率和蛋白印迹法测定细胞凋亡相关蛋白表达变化。结果 宫颈癌细胞系中miRNA-34a表达量显著高于阴性对照组(P<0.05),过表达miRNA-34a宫颈癌细胞增殖抑制率显著高于阴性对照组(P<0.05),细胞克隆形成率显著低于阴性对照组(P<0.05)。流式细胞仪结果显示过表达miRNA-34a宫颈癌细胞凋亡率显著高于对照组(P<0.05)。蛋白印迹法结果显示4 Gy+过表达miRNA-34a细胞中cleaved caspase 9和cleaved PARP蛋白表达量高于过表达miRNA-34a细胞。结论 本研究成功构建miRNA-34a过表达宫颈癌细胞系,miRNA-34a过表达增强宫颈癌细胞放射敏感性,其机制与激活细胞凋亡通路有关。     

Celecoxib,a COX-2 Selective Inhibitor,Induces Cell Cycle Arrest at the G2/M Phase in HeLa Cervical Cancer Cells

Celecoxib, a selective inhibitor of COX-2, showed cytotoxic effects in many cancer cell lines including cervical cancer cells. This study investigated the effect of celecoxib on cell cycle arrest in HeLa cervical cancer cells through p53 expression. In vitro anticancer activity was determined with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method. A double staining method was applied to investigate the mechanism of cell death, cell cycling was analyzed by flow cytometryand immunocytochemistry was employed to stain p53 expression in cells. Celecoxib showed strong cytotoxic effects and induced apoptosis with an IC50 value of 40 M. It induced cell cycle arrest at G2/M phase by increasing level of p53 expression on HeLa cells.     

肼苯哒嗪对宫颈癌细胞系侵袭力的影响

目的探讨肼苯哒嗪去甲基化作用对人宫颈癌细胞系HeLa（HPV18型）、CaSki和SiHa（HPV16型）细胞侵袭力的抑制影响。方法Transwell侵袭小室法检测肼苯哒嗪处理前后人宫颈癌细胞系HeLa、CaSki和SiHa的侵袭力。甲基化特异性PCR（MSP）法检测肼苯哒嗪处理前后各细胞系中APC基因和CDH1基因5′端启动子区CpG岛甲基化状态。实时荧光定量PCR（FQ-PCR）法检测肼苯哒嗪处理前后,上述三种细胞系中APC和CDH1 mRNA表达情况。结果与未处理组比较,10 μmol/L肼苯哒嗪对人宫颈癌细胞系HeLa、CaSki和SiHa的侵袭力抑制作用差异无统计学意义,20 μmol/L与40 μmol/L肼苯哒嗪对人宫颈癌细胞系HeLa、CaSki和SiHa的侵袭力抑制作用差异有统计学意义(P<0.05,P<0.01);且不同浓度之间有差异,以40 μmol/L肼苯哒嗪抑制作用最强。40 μmol/L肼苯哒嗪处理后,上述三种细胞系中APC和CDH1基因呈现不同程度的去甲基化现象。经40 μmol/L肼苯哒嗪处理后,上述三种细胞系中APC mRNA表达分别是处理前的5.89倍、8.46倍及0.97倍,CHD1mRNA表达分别是处理前的4.82倍、5.90倍及8.46倍。结论一定浓度的肼苯哒嗪能明显抑制宫颈癌细胞系HeLa、CasKi和SiHa的侵袭力,其作用机制之一是通过去甲基化作用影响APC和CHD1的表达。     

Activation of the retinoblastoma tumor suppressor mediates cell cycle inhibition and cell death in specific cervical cancer cell lines

High-risk human papilloma virus (HPV) encodes two oncoproteins, E6 and E7, which are vital to viral replication and contribute to the development of cervical cancer. HPV16 E7 can target over 20 cellular proteins, but is best known for inactivating the retinoblastoma (RB) tumor suppressor. RB functions by restraining cells from entering S-phase of the cell cycle, thus preventing aberrant proliferation. While it is well established that HPV16 E7 facilitates the degradation of the RB protein, the ability of the RB pathway to overcome E7 action is less well understood. In this study the RB-pathway was activated via the overexpression of the p16ink4a tumor suppressor or ectopic expression of an active allele of RB (PSM-RB). While p16ink4a had no influence on cell cycle progression, PSM-RB expression was sufficient to induce a cell cycle arrest in both SiHa and HeLa cells, HPV positive cervical cancer cell lines. Strikingly, this arrest led to the downregulation of E2F target gene expression, which was antagonized via enhanced HPV-E7 expression. Since downmodulation of E7 function is associated with chronic growth arrest and senescence, the effect of PSM-RB on proliferation and survival was evaluated. Surprisingly, sustained PSM-RB expression impeded the proliferation of SiHa cells, resulting in both cell cycle inhibition and cell death. From these studies we conclude that active RB expression can sensitize specific cervical cancer cells to cell cycle inhibition and cell death. Thus, targeted therapies involving activation of RB function may be effective in inducing cell death in cervical cancer.     

Chemoradiation of cervical cancer cells: targeting human papillomavirus E6 and p53 leads to either augmented or attenuated apoptosis depending on the platinum carrier ligand

Recent clinical trials comparing concurrent chemotherapy and radiation with radiation alone in cervical cancer have shown that chemoradiation reduces the risk of death by 30-50%. Despite the clinical success, treatment responses at the cellular level are still inadequately explored. A key event in cervical carcinogenesis is the disruption of p53 tumor suppressor pathway by human papillomavirus (HPV) E6 oncogene. We found that regardless of the HPV type in SiHa (HPV 16+) CaSki (HPV 16+), HeLa (HPV 18+), and UT-DEC-1 (HPV 33+) cell lines, cisplatin, carboplatin, and a novel platinum compound, oxaliplatin, activated a p53 reporter and reduced the HPV E6 mRNA. Carboplatin and oxaliplatin treatment led also to stabilization of p53, whereas none of the platinums changed p73 levels. After irradiation (IR) alone, a decrease in HPV E6 mRNA levels and an activation of the p53-reporter were detected in SiHa, CaSki, and HeLa cells, but not in UT-DEC-1 cells. Concomitant platinum treatment and IR led to poly(ADP-ribose) polymerase cleavage as a sign of caspase-3 activation and apoptosis. Clonogenic survival was enhanced by expressing a dominant negative p53 or ectopic HPV16 E6 in SiHa and HeLa cells treated with IR, carboplatin, or oxaliplatin or with a combination of IR + carboplatin or oxaliplatin. In contrast, dominant negative p53 or ectopic HPV 16 E6 sensitized the cells to cisplatin. Pt chemotherapeutics and radiation had a synergistic cytotoxic effect as determined by Bliss independence criterion. Taken together, p53 has a significant role in the cellular response to chemoradiation treatment in cervical cancer cell lines, but p53 activity may have a dramatically different effect on cell survival depending on the platinum carrier ligand.     

重组RA538,反义c—myc腺病毒对bcl—2高表达细胞系的作用及分子 …

目的 研究重组ＲＡ５３８（Ａｄ－ＲＡ５３８）、反义ｃ－ｍｙｃ腺病毒（Ａｄ－ＡＳｃ－ｍｙｃ）在ｂｃｌ－２高表达细胞系中的作用及其分析机制。方法 采用细胞形态学观察、ＭＴＴ、ＲＴ－ＰＣＲ和Ｎｏｒｔｈｅｒｎ ｂｌｏｔ等方法,研究ＲＡ５３８,反义ｃ０ｍｙｃ重组腺病毒在ｂｃｌ－２高表达的人宫颈癌细胞系ＨｅＬａ－ｂｃｌ２和ＳｉＨａ－ｂｃｌ２以及在其亲本细胞中的生物学作用及其分子机制。结果 以ｌｉｐｏｆｅｃｔｉ     

Therapeutic potential of an adenovirus expressing p73 beta, a p53 homologue, against human papilloma virus positive cervical cancer in vitro and in vivo

Human papilloma virus (HPV) infection is the most important risk factor for cervical cancer development. p53 based gene therapy is not suitable for cervical cancer because HPV oncoprotein E6 inactivates p53 protein by targeting it for ubiquitin mediated degradation. Here we evaluated the efficiency of Ad-p73, a replication deficient adenovirus expressing p73beta a p53 homologue, to inhibit the growth of HPV positive cervical cancer cells in vitro using tissue culture system and in vivo using human xenografts in nude mice. Ad-p73, but not Ad-p53 (p53 adenovirus), inhibited the growth in vitro of three different HPV positive cervical cancer cell lines, HeLa, ME180, and SiHa, efficiently, which correlated with stable expression of functional p73 protein. However, the growth of a HPV negative cervical cancer cell line, C33A, was inhibited equally by both Ad-p73 and Ad-p53. In addition, we show that Ad-p73 preinfected HeLa cells and HCT116 E6 cells, an E6 stable cell line, failed to form tumors in nude mice unlike Ad-p53 or Ad-LacZ preinfected cells. Moreover, Ad-p73, but not Ad-p53, inhibited completely the growth of already established tumors of HeLa or HCT116 E6 cells. Furthermore, the ability of p73 to inhibit the growth of these tumors correlated with the stable expression of p73 protein with the concomitant induction of its target gene p21(WAF1/CIP1) and induction of apoptosis in tumor cells. These results suggest that Ad-p73 inhibits efficiently the growth in vitro and tumorigenicity and tumor growth in vivo of HPV positive cervical cancer cells and that p73-based approach should be explored as a potential therapeutic model for the treatment of cervical cancer.     

Reversal of Resistance towards Cisplatin by Curcumin in Cervical Cancer Cells

Epigenetic regulators like histone deacetylases (1 and 2), and viral onco-proteins (E6/E7) are known to beoverexpressed in cervical cancer cells. The present study was designed to investigate the effect of curcumin onHDACs (1 and 2) and HPV E6/E7 in the cervical cancer cell line SiHa and a drug resistant clone SiHaR (derivedfrom SiHa). It was further intended to investigate whether curcumin could sensitize the cells towards cisplatininduced cell killing by modulation of multi drug resistant proteins like MRP1 and Pgp1. Curcumin inhibitedHDACs, HPV expression and differentially increased acetylation and up-regulation of p53 in SiHa and SiHaR,leading to cell cycle arrest at G1-S phase. Up-regulation of pRb, p21, p27 and corresponding inhibition of cyclinD1 and CDK4 were observed. Cisplatin resistance in SiHaR due to over-expression of MRP1 and Pgp1 wasovercome by curcumin. Curcumin also sensitized both the cervical cancer cells towards cisplatin induced cellkilling. Inhibition of HDACs and HPVs led to cell cycle arrest at G1/S phase by alteration of cell cycle regulatoryproteins. Suppression of MRP1 and Pgp1 by curcumin resulted in sensitization of cervical cancer cells, loweringthe chemotherapeutic dose of the drug cisplatin.     

Leptomycin B enhances CDDP-sensitivity via nuclear accumulation of p53 protein in HPV-positive cells

Cervical cancer, which commonly contains a wild-type p53 gene, is highly correlated with human papilloma virus (HPV) infection. Because the oncoprotein E6, derived from HPV, inhibits the function of p53 protein, the inhibition of apoptosis via the p53 pathway by HPV may be related to cisplatin (CDDP)-sensitivity in cervical cancer. We conducted the present study to determine whether and how HPV is related to CDDP-sensitivity in HPV-positive cervical cancer cells. We used cervical carcinoma cell lines HeLa with integrated HPV 18 and SiHa with integrated HPV 16. An HPV-negative cell line, Yumoto, with wild-type p53 gene was used as a control. Leptomycin B (LMB) enhanced sensitivity to CDDP and CDDP-induced apoptosis in HeLa and SiHa cells, but not in Yumoto cells. After exposure to LMB or CDDP alone, we observed weak p53 staining in HeLa, SiHa and Yumoto cells. Nuclear p53 staining was significantly increased by combined treatment with CDDP and LMB in HeLa and SiHa cells, but not in Yumoto cells. The expression of p53 and Bax protein increased with exposure to CDDP and was enhanced by LMB in HeLa and SiHa cells. The present study demonstrated that LMB enhanced CDDP-sensitivity via nuclear accumulation of p53 protein in HPV-positive cells.     

脂肪抑制素对宫颈癌细胞增殖、克隆形成、侵袭、迁移的抑制作用及相关机制研究

目的:探究脂肪抑制素对宫颈癌细胞增殖、克隆形成能力、侵袭及迁移能力以及细胞周期、细胞凋亡的影响。方法:选取宫颈癌细胞系SiHa,利用不同浓度脂肪抑制素进行培养。通过MTT实验、平板克隆形成实验、Transwell实验及流式细胞术检测实验分别检测脂肪抑制素对宫颈癌细胞增殖、克隆形成能力、侵袭/迁移能力以及细胞周期/细胞凋亡的影响,探究脂肪抑制素对宫颈癌细胞的抗肿瘤作用。结果:MTT实验显示,脂肪抑制素对SiHa细胞的增殖/生长具有明显抑制作用,存在时间和剂量依赖性(P＜0.05);根据细胞增殖率得出72 h时SiHa细胞的IC50为16.98 μmol/L。平板克隆形成实验显示,脂肪抑制素明显降低了SiHa细胞的克隆形成能力,具有剂量依赖性（P＜0.01）。Transwell实验显示,脂肪抑制素也明显降低SiHa细胞侵袭/迁移能力,具有剂量依赖性（P＜0.001）。流式细胞术检测实验显示,较高浓度脂肪抑制素可诱导宫颈癌细胞SiHa的细胞周期停滞在G2/M期,促进其细胞凋亡（P＜0.05）。结论:脂肪抑制素对宫颈癌细胞具有明显抗肿瘤作用,可作为宫颈癌治疗的新药物。