Terfenadine resensitizes doxorubicin activity in drug-resistant ovarian cancer cells via an inhibition of CaMKII/CREB1 mediated ABCB1 expression.

Ovarian cancer is one of the most lethal gynecological malignancies. Recurrence or acquired chemoresistance is the leading cause of ovarian cancer therapy failure. Overexpression of ATP-binding cassette subfamily B member 1 (ABCB1), commonly known as P-glycoprotein, correlates closely with multidrug resistance (MDR). However, the mechanism underlying aberrant ABCB1 expression remains unknown. Using a quantitative high-throughput combinational screen, we identified that terfenadine restored doxorubicin sensitivity in an MDR ovarian cancer cell line. In addition, RNA-seq data revealed that the Ca2+-mediated signaling pathway in the MDR cells was abnormally regulated. Moreover, our research demonstrated that terfenadine directly bound to CAMKIID to prevent its autophosphorylation and inhibit the activation of the cAMP-responsive element-binding protein 1 (CREB1)-mediated pathway. Direct inhibition of CAMKII or CREB1 had the same phenotypic effects as terfenadine in the combined treatment, including lower expression of ABCB1 and baculoviral IAP repeat-containing 5 (BIRC5, also known as survivin) and increased doxorubicin-induced apoptosis. In this study, we demonstrate that aberrant regulation of the Ca2+-mediated CAMKIID/CREB1 pathway contributes to ABCB1 over-expression and MDR creation and that CAMKIID and CREB1 are attractive targets for restoring doxorubicin efficacy in ABCB1-mediated MDR ovarian cancer.

The Value of MicroRNA-375 Detection for Triaging Primary Human Papillomavirus Positive Women: A Cross-Sectional Study in a General Population.

PURPOSE: This study aims to validate the value of microRNA (miRNA) detection for triaging human papillomavirus (HPV)-positive women in the general population. PATIENTS AND METHODS: miR-375 detection in cervical exfoliated cells has been demonstrated to have the superior value to cytology in triaging primary HPV-positive women in the hospital population. In this study, residual samples of cervical exfoliated cells from 10,951 women in a general population were used to detect miRNA. The performance efficiency of miRNA detection in identifying high-grade cervical intraepithelial neoplasia (CIN) was evaluated. Pearson chi-square test and McNemar pairing test were used to compare miRNA detection and cytology. RESULTS: In valid 9,972 women aged 25-65, miR-375 expression showed a downward trend along with an increase in cervical lesion severity. The expression level of miR-375 ≤1.0 × 10-3 was identified as positive. In the HPV-positive and 12 HPV genotypes other than 16/18 (HR12)-positive women, miR-375 detection showed equivalent sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) to that of cytology (≥ASC-US) and higher or similar sensitivity and NPV but lower specificity and PPV than that of cytology (≥ASC-H) in identifying CIN3+ and CIN2+. In HPV 16-positive women, miR-375 positivity had higher sensitivity and NPV but lower specificity and PPV than that of cytology (≥ASC-H and HSIL) in identifying CIN3+ and CIN2+. The immediate CIN3+ risk of miR-375 positivity was 19.8% (61/308) in HPV-positive, 10.8% (22/204) in HR12-positive, and 43.5% (37/85) in HPV16-positive women, respectively. CONCLUSION: The detection of miR-375 in cervical exfoliated cells may be an optional method for triaging primary HPV-positive women in population-based cervical cancer screening.

Quantitative Chemotherapeutic Profiling of Gynecologic Cancer Cell Lines Using Approved Drugs and Bioactive Compounds.

Heterogeneous response to chemotherapy is a major issue for the treatment of cancer. For most gynecologic cancers including ovarian, cervical, and placental, the list of available small molecule therapies is relatively small compared to options for other cancers. While overall cancer mortality rates have decreased in the United States as early diagnoses and cancer therapies have become more effective, ovarian cancer still has low survival rates due to the lack of effective treatment options, drug resistance, and late diagnosis. To understand chemotherapeutic diversity in gynecologic cancers, we have screened 7914 approved drugs and bioactive compounds in 11 gynecologic cancer cell lines to profile their chemotherapeutic sensitivity. We identified two HDAC inhibitors, mocetinostat and entinostat, as pan-gynecologic cancer suppressors with IC50 values within an order of magnitude of their human plasma concentrations. In addition, many active compounds identified, including the non-anticancer drugs and other compounds, diversely inhibited the growth of three gynecologic cancer cell groups and individual cancer cell lines. These newly identified compounds are valuable for further studies of new therapeutics development, synergistic drug combinations, and new target identification for gynecologic cancers. The results also provide a rationale for the personalized chemotherapeutic testing of anticancer drugs in treatment of gynecologic cancer.

Small Molecules Identified from a Quantitative Drug Combinational Screen Resensitize Cisplatin's Response in Drug-Resistant Ovarian Cancer Cells.

Drug resistance to chemotherapy occurs in many ovarian cancer patients resulting in failure of treatment. Exploration of drug resistance mechanisms and identification of new therapeutics that overcome the drug resistance can improve patient prognosis. Following a quantitative combination screen of 6060 approved drugs and bioactive compounds in a cisplatin-resistant A2780-cis ovarian cancer cell line, 38 active compounds with IC50s under 1 µM suppressed the growth of cisplatin-resistant ovarian cancer cells. Among these confirmed compounds, CUDC-101, OSU-03012, oligomycin A, VE-821, or Torin2 in a combination with cisplatin restored cisplatin's apoptotic response in the A2780-cis cells, while SR-3306, GSK-923295, SNX-5422, AT-13387, and PF-05212384 directly suppressed the growth of A2780-cis cells. One of the mechanisms for overcoming cisplatin resistance in these cells is mediated by the inhibition of epidermal growth factor receptor (EGFR), though not all the EGFR inhibitors are equally active. The increased levels of total EGFR and phosphorylated-EGFR (p-EGFR) in the A2780-cis cells were reduced after the combined treatment of cisplatin with EGFR inhibitors. In addition, a knockdown of EGFR mRNA reduced cisplatin resistance in the A2780-cis cells. Therefore, the top active compounds identified in this work can be studied further as potential treatments for cisplatin-resistant ovarian cancer. The quantitative combinational screening approach is a useful method for identifying effective compounds and drug combinations against drug-resistant cancer cells.

Neural stem cells for disease modeling and evaluation of therapeutics for infantile (CLN1/PPT1) and late infantile (CLN2/TPP1) neuronal ceroid lipofuscinoses.

BACKGROUND: Infantile and late infantile neuronal ceroid lipofuscinoses (NCLs) are lysosomal storage diseases affecting the central nervous system (CNS). The infantile NCL (INCL) is caused by mutations in the PPT1 gene and late-infantile NCL (LINCL) is due to mutations in the TPP1 gene. Deficiency in PPT1 or TPP1 enzyme function results in lysosomal accumulation of pathological lipofuscin-like material in the patient cells. There is currently no small-molecular drug treatment for NCLs. RESULTS: We have generated induced pluripotent stem cells (iPSC) from three patient dermal fibroblast lines and further differentiated them into neural stem cells (NSCs). Using these new disease models, we evaluated the effect of δ-tocopherol (DT) and hydroxypropyl-ß-cyclodextrin (HPBCD) with the enzyme replacement therapy as the control. Treatment with the relevant recombinant enzyme or DT significantly ameliorated the lipid accumulation and lysosomal enlargement in the disease cells. A combination therapy of δ-tocopherol and HPBCD further improved the effect compared to that of either drug used as a single therapy. CONCLUSION: The results demonstrate that these patient iPSC derived NCL NSCs are valid cell- based disease models with characteristic disease phenotypes that can be used for study of disease pathophysiology and drug development.

Focal adhesion kinases crucially regulate TGFß-induced migration and invasion of bladder cancer cells via Src kinase and E-cadherin.

Focal adhesion kinase (FAK) is a non-receptor protein-tyrosine kinase that is triggered off by special extracellular signals such as some growth factors and integrins. FAK is found in cell-matrix attachment sites and implicated in cell migration, invasion, movement, gene expression, survival and apoptosis. In this study, we aimed to investigate whether FAK plays a role in invasion and migration of bladder cancer cells. Using an FAK-specific small interfering RNA (siRNA) and an FAK inhibitor PF-228, we found that inhibition of FAK tyrosine phosphorylation or knockdown of FAK suppressed invasion and migration of bladder cancer cells. Src is an important mediator of FAK-regulated migratory and invasive activity. Tyrosine phosphorylation of Src and FAK is mutually dependent and plays a key role in transforming growth factor beta (TGFß)-induced invasion and migration. E-cadherin acts downstream of FAK and is a critical negative regulator in FAK-regulated invasion and migration of bladder cancer cells. These findings imply that FAK is involved in oncogenic signaling of invasion and migration, which can be a novel therapeutic target to treat patients with bladder cancer.

The overexpression of scaffolding protein NEDD9 promotes migration and invasion in cervical cancer via tyrosine phosphorylated FAK and SRC.

NEDD9, a focal adhesion scaffolding protein, has been recently proposed to regulate invasion and metastasis in some cancer types, but unknown in cervical cancer. The aim of this study was to determine if NEDD9 was involved in the progression and metastasis of cervical cancer. The experimental results showed NEDD9 protein was overexpressed in cervical cancer compared with normal cervical epithelium tissues. Overexpression of NEDD9 was correlated with histological grading, lymph node metastasis, and FIGO stage of cervical cancer. Silencing NEDD9 resulted in tyrosine dephosphorylation of FAK and SRC oncoproteins, and decreased cell migration and invasion in the cervical carcinoma SiHa and HeLa cells. Overexpression of NEDD9 led to tyrosine phosphorylation of FAK and SRC oncoproteins, and increased cell migration and invasion. Moreover, tyrosine phosphorylation of NEDD9 was significantly decreased via suppressing tyrosine phosphorylation of FAK or SRC, suggesting a positive feedback loop of tyrosine phosphorylation between NEDD9 and FAK or SRC. In addition, our data showed that silencing NEDD9 decreased Vimentin expression and increased E-cadherin expression in cervical cancer cells, and vice versa. E-cadherin was subject to regulation of NEDD9, FAK and SRC, but altered neither tyrosine-phosphorylated nor total NEDD9. Our findings suggest that NEDD9 is overexpressed in cervical cancer tissues and cells, and overexpressed NEDD9 promotes migration and invasion in cervical carcinoma cells, probably via a positive feedback loop of tyrosine phosphorylation between NEDD9 and FAK or SRC.

The preparation of human papillomavirus type 58 vaccine and exploring its biological activity and immunogenicity in vitro.

OBJECTIVES: Human papillomavirus (HPV) type 58 is the second most prevalent virus infection among Chinese women. To develop an HPV58 vaccine that combines both prophylactic and therapeutic functions, we generate a chimeric virus-like particle (cVLP). METHODS: The cVLPs contain both whole length L1 and parts of E7 peptides either from E7 amino acids (aa) 50 to aa72 or from E7 aa4 to aa12. The HPV58 L1-E7aa50-72 and L1-E7aa4-12 fusion proteins were revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and confirmed by Western blot (Supplementary Digital Content 1, http://links.lww.com/IGC/A40, which shows alignment of the protein sequence between HPV58 L1-E7aa50-72/4-12 and standard sequence). Protein folding and location of cVLPs were identified by transmission electron microscope. The immunogenicity of the fusion protein was tested by enzyme-linked immunospot assay. RESULTS: Transmission electron microscope showed that the fusion protein formed cVLPs by self-assembly and the majority of particles located in the nucleus of the sf-9 insect cells. The cVLPs displayed a strong ability to agglutinate erythrocytes, which is distinguished from the parental VLPs. In addition, the purified HPV58 L1-E7aa50-72 or L1-E7aa4-12 fusion protein induced significant numbers of interferon γ-expressing E7aa50-72- or E7aa4-12-specific CD8 T cells. DISCUSSION: Our results indicate that the insertion of the E7aa50-72 or E7aa4-12 peptides behind L1 did not disrupt the assembly of cVLPs and provided potent immunogenicity and bioactivity, which created a powerful basis for further preparations of HPV58 vaccines with prophylactic and therapeutic effects for the treatment of HPV58-related diseases including cervical cancer.

Early proteins E6 and E7 of human papillomavirus may attenuate ischemia-reperfusion injury.

It is well known that human papillomaviruses (HPVs) involve in the pathogenesis of some specific carcinomas such as cervical cancer. Experimental and clinical studies have shown that early proteins E6 and E7 played the most important role in the cervical carcinogenesis. Early proteins E6 and E7 of HPV both are oncoproteins for they disable specific tumor suppressor proteins, p53 and pRb, and disturb apoptosis against carcinogenesis. Both p53 and pRb play an important role in regulating apoptosis and preventing cell immortalization, but they also mediate ischemia/reperfusion-associated apoptosis and give rise to ischemia-reperfusion injury (IRI). Several studies showed inhibition of apoptosis may provide promising approaches to ameliorating IRI in ischemia/reperfusion. Both small-molecule chemical inhibitor and siRNA against p53 block p53-dependent apoptosis and protect organ function from IRI. Similarly, inhibiting pRb can restrain ischemia/reperfusion-associated apoptosis. Based on these studies, we propose a novel hypothesis that early proteins E6 and E7 of HPV attenuate ischemia-reperfusion injury by inhibiting apoptosis and inactivating p53 and pRb. It is possible that the two oncoproteins can be used to protect organ function from ischemia-reperfusion injury in special clinical conditions such as organ transplant, stroke, cardiopulmonary bypass, and myocardial infarction.

Triggering of death receptor apoptotic signaling by human papillomavirus 16 E2 protein in cervical cancer cell lines is mediated by interaction with c-FLIP.

Human papillomavirus (HPV) E2 gene disruption is one of the key features of HPV-induced cervical malignant transformation. Though it is thought to prevent progression of carcinogenesis, the pro-apoptotic function of E2 protein remains poorly understood. This study shows that expression of HPV16 E2 induces apoptosis both in HPV-positive and -negative cervical cancer cell lines and leads to hyperactivation of caspase-8 and caspase-3. Activation of these signaling factors is responsible for the observed sensitivity to apoptosis upon treatment with anti-Fas antibody or TNF-α. In addition, immunoprecipitation experiments clearly show an interaction between HPV16 E2 and c-FLIP, a key regulator of apoptotic cell death mediated by death receptor signaling. Moreover, c-FLIP and a caspase-8 inhibitor protect cells from HPV16 E2-mediated apoptosis. Overexpression of c-FLIP rescues cervical cancer cells from apoptosis induced by HPV16 E2 protein expression. The data suggest that HPV16 E2 abrogates the apoptosis-inhibitory function of c-FLIP and renders the cell hypersensitive to the Fas/FasL apoptotic signal even below threshold concentration. This suggests a novel mechanism for deregulation of cervical epithelial cell growth upon HPV-induced transformation, which is of great significance in developing therapeutic strategies for intervention of cervical carcinogenesis.

Selective targeting of HPV-16 E6/E7 in cervical cancer cells with a potent oncolytic adenovirus and its enhanced effect with radiotherapy in vitro and vivo.

Recent studies have shown that oncolytic adenovirus specifically targeted tumor cells while sparing normal cells. Here, we report a novel E1A-mutant adenovirus (M6) with antisense HPV16 E6 E7 DNA inserted into the deleted 6.7K/gp19K region of E3. The target effects of M6 on HPV16-positive cervical cancer cells were evaluated in vivo and in vitro. By using cytopathic effect (CPE) and viral replication assays, we verified M6 was competent to selectively replicate in cervical cancer cells in vitro. Moreover, we found infection of M6 was able to inhibit the expression of HPV16 E6 and E7 oncogenes and induce apoptosis of HPV16-positive cervical cancer cells. Further analysis in vitro revealed that the invasive ability of SiHa cells was significantly inhibited by M6. To determine if M6 synergized with radiotherapy-induced anti-tumor activity against HPV16-related cancer cells, we transfected SiHa cells with M6 followed by a single exposure to radiation. A significantly suppression of cell growth and induced apoptosis was observed in SiHa cells received M6 transfection combined with radiotherapy. Animal experiments showed that M6 transfection notably improved the survival of tumor-bearing mice in combination with radiotherapy, much superior to that of those treated by Adv5/dE1A plus radiation or M6 alone. These findings indicated the anti-tumoral efficacy of M6 on HPV16-positive cervical cancer cells and its synergic therapeutic application in radiation for cervical cancer.

Short hairpin RNA targeting c-FLIP sensitizes human cervical adenocarcinoma Hela cells to chemotherapy and radiotherapy.

c-FLIP inhibits caspase-8 activation and cell apoptosis mediated by death receptors. The present study aims at determining the effects of c-FLIP targeted vector-based short hairpin RNA (shRNA) on cell growth and evaluating its modulation of responsiveness to drugs and radiotherapy in cervical adenocarcinoma Hela cells. cFLIP expression of the cells transfected with shRNA against c-FLIP was significantly down-regulated after 72 h. c-FLIP silencing markedly suppressed cell proliferation and increased cell apoptosis. The activation of caspase-8 and caspase-3 was induced with shRNA targeting cFLIP with the passage of time after transfection. Furthermore, Vector-based shRNA against c-FLIP subsequently increased the sensitivity to cisplatin, iritican and Co60 radiotherapy by about 4- to 6-folds in Hela cells. Our data suggest that vector-based shRNA effectively inhibited c-FLIP expression, enhanced the expression level of caspase-8 and caspase-3 to induce cell apoptosis, probably with the higher efficacy in combination therapies with conventional chemotherapy and radiotherapy in cervical adenocarcinoma.

RNA interference against HPV16 E7 oncogene leads to viral E6 and E7 suppression in cervical cancer cells and apoptosis via upregulation of Rb and p53.

The simultaneous expression of human papillomavirus type 16 (HPV16) E6 and E7 oncogenes is pivotal for malignant transformation and maintenance of malignant phenotypes. Silencing these oncogenes is considered to be applicable in molecular therapies of human cervical cancer. However, it remains to be determined whether HPV16 E6 and E7 could be both silenced to obtain most efficient antitumor activity by using RNA interference (RNAi) technology. Herein, we designed a small interfering RNA (siRNA) targeting HPV16-E7 region to degrade either E6, or truncated E6 (E6*) and E7 mRNAs and to simultaneously knockdown both E6 and E7 expression. Firstly, the sequence targeting HPV16-E7 region was inserted into the shRNA packing vector pSIREN-DNR, yielding pSIREN-16E7 to stably express corresponding shRNA. HPV16-transformed SiHa and CaSki cells were used as a model system; RT-PCR, Western Blotting, MTT assay, TUNEL staining, Annexin V apoptosis assay and flow cytometry were applied to examine the effects of pSIREN-16E7. Our results indicated that HPV16-E7 specific shRNA (16E7-shRNA) induced selective degradation of E6 and E7 mRNAs and proteins. E6 silencing induced accumulation of cellular p53 and p21. In contrast, E7 silencing induced hypophosphorylation of retinoblastoma (Rb) protein. The loss of E6 and E7 reduced cell growth and ultimately resulted in massive apoptotic cell death selectively in HPV-positive cancer cells, compared with the HPV-negative ones. We demonstrated that 16E7-shRNA can induce simultaneous E6 and E7 suppression and lead to striking apoptosis in HPV16-related cancer cells by activating cellular p53, p21 and Rb. Therefore, RNAi using E7 shRNA may have the gene-specific therapy potential for HPV16-related cancers.

[Antisense targeting to human papillomavirus 18 E6/E7 affects the proliferation and apoptosis of human cervical carcinoma: an in vitro experiment with HeLa cells].

OBJECTIVE: To investigate the effect of eukaryotic fluorescent expression vector carrying antisense human papillomavirus (HPV) 18 E6/E7 on the growth and proliferation of human cervical carcinoma. METHODS: The HPV18 E6E7 with the length of 716 bp was amplified by PCR, the PCR product was inversely inserted into the eukaryotic fluorescent expression vector pEGFP-C1 so as to construct the recombinant eukaryotic expression plasmid pEGFP-HPV18E6E7as (EGFP-18AS). Human cervical carcinoma cells of the line HeLa were cultured and randomly divided into 3 groups: Group A transfected with the recombinant plasmid EGFP-18AS, Group B transfected with the blank plasmid pEGFP-C1, and Group C without transfection used as control group. The mRNA expression of HPV 18 E6/E7 in the HeLa cells was detected by RT-PCR and protein expression of HPV18 E6/E7 HPV 18 E6/E7 in the HeLa cells was detected by. Western blotting MTT assay was performed to dynamically monitor the surviving cells and the cell apoptosis was observed by flow cytometry and fluorescence microscopy. RESULTS: The protein and mRNA expression levels of HPV18 E6/E7 in the HeLa cells transfected with HeLa/18AS were both remarkably lower than those in the HeLa cells transfected with blank plasmid and those of the control group. The numbers of surviving HeLa cells of Group A was significantly lower than those of Groups B and C (both P < 0.05). The phenomenon of arrest of G(1) phase was remarkable in Group A. The apoptotic rate of the cells of Group A was 47.21%, significantly higher than those of Groups B and C (14.18% and 3.36% respectively, both P < 0.05). An increased number of cells with chromosome condensation and fragmentation was found in Group A as compared with Groups B and C. CONCLUSION: The recombinant pEGFP-HPV18E6E7as can effectively inhibit the growth and proliferation of human cervical carcinoma HeLa cells, and further induce the cell apoptosis. The antisense RNA technology is available and may provide a new way to gene therapy of the cervical carcinoma.

Relationship between the expression of telomerase and human papillomavirus infection in invasive uterine cervical carcinoma.

Telomerase activity was examined in invasive cervical carcinoma to assess whether it is activated during cervical malignant transformation and to look for its possible association with human papillomavirus (HPV) infection. Histologically confirmed invasive cervical carcinomas and benign cervices were assayed for telomerase activity by using a modified telomere repeat amplification protocol (TRAP). The same cases were subjected to polymerase chain reaction (PCR) detection of HPV by using consensus primers and type-specific (HPV types 16 and 18) primers. Telomerase activity was detected in 40 of 45 (88.9%) invasive cervical carcinomas and 2 (all chronic cervicitis) of 50 (4%) benign cervical lesions. HPV was detected in 36 (24 HPV-16 and 4 HPV-18 cases) of 45 (80%) invasive cervical carcinomas and 20 (11 HPV-16 and 1 HPV-18 cases) of 50 (40%) benign cervical changes. There was a significant correlation between the expression of telomerase with histological grade (omega=0.44, P<0.005), but no correlation was found between telomerase expression and HPV-18 (P>0.05). Although larger sample studies are needed, there seems to be a clear association between telomerase upregulation and HPV status, mainly HPV-16 infection.

Antisense targeting human papillomavirus type 16 E6 and E7 genes contributes to apoptosis and senescence in SiHa cervical carcinoma cells.

OBJECTIVE: Human papillomavirus type 16 (HPV-16) is a high-risk DNA tumor virus involved in the development of cervical carcinomas. Substantial studies have demonstrated that E6 and E7 oncoproteins of HPV-16 could induce cell proliferation and immortalization. Repression of E6 and/or E7 oncogenes may induce cervical cancer cells to undergo apoptosis or senescence. The purpose of this study was to determine whether activation of the p53 and retinoblastoma (Rb) pathway by HPV-16 E6 and E7 repression was responsible for apoptosis and senescence of cervical cancer cells and to explore the potential of an antisense RNA (AS) transcript for gene therapy of cervical cancer. METHOD: The antisense RNA directed against HPV-16 E6 and E7 (16AS) was constructed, and its effects on cell apoptosis and senescence of SiHa cervical carcinoma cells harboring HPV-16 were analyzed. The efficiency of 16AS was evaluated with RT-PCR, Western blotting, flow cytometry analysis, Hoechst 33258 staining, senescent cell morphology observation and senescence-associated beta-galactosidase staining. RESULTS: The sufficient repression of HPV-16 E6 and E7 oncogenes were achieved in 16AS-transfected SiHa cells, which led to obvious apoptosis and replicative senescence of tumor cells. Furthermore, the downregulation of HPV-16 E6 and E7 by 16AS transfection resulted in remarkable increase of both p53 expression and hypophosphorylated p105Rb level in SiHa cells. CONCLUSION: These results demonstrate that reduction of E6 and E7 expression is sufficient to induce SiHa cells to undergo apoptosis and senescence and suggest that transfection of cervical cancer cells with HPV-16 E6 and E7 antisense RNA is a potential approach to treat HPV-16-positive cervical cancers.

The relationship between c-FLIP expression and human papillomavirus E2 gene disruption in cervical carcinogenesis.

OBJECTIVE: Human papillomavirus (HPV) is the essential causative factor in cervical carcinogenesis, and apoptosis inhibition is one of the key features of HPV-induced malignant transformation. This study is to investigate the possible cause-effect association between high-risk HPV and cellular FLICE-like inhibitory protein (c-FLIP), an important apoptosis regulator, during cervical carcinogenesis. METHODS: A series of 80 archival samples, including 20 squamous cervical carcinomas (SCC) 54 cervical intraepithelial neoplasia (CIN) lesions and 6 normal cervical tissues, were subjected for c-FLIP immunohistochemical staining and HPV HC-II analysis. Typing HPV-16 infection was analyzed by the polymerase chain reaction (PCR), and its status was assessed with the integrity and disruption of the HPV-16 E2 gene, which was amplified in three overlapping fragments. RESULTS: The types of HR-HPV infection and E2 disruption were associated closely with cervical lesion severity. There was a significant relationship between lesion grade and c-FLIP expression level. c-FLIP overexpression was also closely associated with HR-HPV infection and its integration status. Multivariate regression analysis revealed c-FLIP as a strong independent predictor for CIN, with 100% PPV, and showed 90.9% PPV in detecting HR-HPV, and remained a significance factor to rule out which case has no HR-HPV integration, with a 94.7% sensitivity and a 90.0% NPV. CONCLUSIONS: The present data approved that c-FLIP overexpression is related significantly to the presence of HR-HPV infection and its integration status during progression of cervical squamous cell cancer and confirmed the role of c-FLIP as an early marker of cervical carcinogenesis.

[Reversal effect of antisense RNA targeting human papillomavirus 16 (HPV16) E6E7 on malignancy of human cervical cancer cell line SiHa].

BACKGROUND & OBJECTIVE: The ubiquitinated degradation of p53 can be induced by human papillomavirus type 16 (HPV16) early gene 6 (E6); the phosphorylated inactivation of pRb can be induced by HPV16 E7. They are closely associated with the carcinogenesis and progression of cervical cancer. This study was to investigate the effects of HPV16 E6E7 antisense RNA on the expression of oncogene E6 and E7 and apoptosis of human cervical cancer cell line SiHa harboring HPV16 genome. METHODS: The antisense sequence of HPV16 E6E7 was cloned into eukaryotic expression vector pEGFP to prepare recombinant plasmid containing E6E7AS, which was transfected into SiHa cells. The mRNA and protein levels of E6 and E7 gene were detected by Western blot and reverse transcription-polymerase chain reaction (RT-PCR). Cell proliferation after transfection was evaluated by MTT assay. The apoptosis of transfected SiHa cells was assessed by flow cytometry (FCM) and confocal laser microscopy. RESULTS: After transfection of HPV16 E6E7 antisense RNA, the mRNA and protein levels of HPV16 E6 and E7 in SiHa cells were obviously decreased. The proliferation activity of SiHa/E6E7AS cells was significantly lower than that of SiHa/EGFP and SiHa cells (0.50+/-0.05 vs. 1.01+/-0.06, 1.28+/-0.06, P<0.05). The apoptosis rate was significantly higher in SiHa/E6E7AS cells than in SiHa/EGFP and SiHa cells [(59.3+/-11.3)% vs. (9.4+/-1.8)%, (2.1+/-0.4)%, P<0.05]. The apoptotic cells increased noticeably after transfection. CONCLUSION: Down-regulating HPV16 E6 and E7 with antisense RNA induces apoptosis in SiHa cells, and may be useful for HPV-associated malignancy gene therapy.