Advances in the development of therapeutic nucleic acids against cervical cancer

Role and Mechanism of Exosome CircRNA Eukaryotic Translation Initiation Factor 4γ2 (EIF4G2) in Cervical Cancer

Our work was to evaluate Exosome CircRNA EIF4G2 in cervical cancer development. Methods: Using Hela and Siha in our present study. Transfection vector, exosome cirEIF4G2, exosome si-NC or exosome si-circEIF4G2 in cells. Using RT-qPCR to measure circEIF4G2 gene expression in difference cell groups. Evaluating cell proliferation, apoptosis, invasion and wound healing rate by MTT, flow cytometry, transwell and wound healing assay. The relative proteins, HPV16 E6 and HPV16 E7, were evaluated by WB assay. With Exosome CircRNA EIF4G2 transfection, Hela and Siha cells proliferation, invasion cells number and wound healing rates were significantly increased and cells apoptosis were significantly depressed (P < 0.001, respectively) with HPV16 E6 and HPV16 E7 proteins expression were significantly up-regulation (P < 0.001, respectively). However, with Exosome si-CircRNA EIF4G2 transfection, Hela and Siha cells proliferation, invasion cells number and wound healing rates were significantly depressed and cells apoptosis were significantly increased (P < 0.001, respectively) with HPV16 E6 and HPV16 E7 proteins expression were significantly down-regulation (P < 0.001, respectively). Exosome CircRNA EIF4G2 as an oncology role in cervical cancer via regulation HPV16 E6/E7 up-regulation in vitro study.

CRISPR/Cas9 nanoeditor of double knockout large fragments of E6 and E7 oncogenes for reversing drugs resistance in cervical cancer

Drug resistance of tumor cells is always a headache problem in clinical treatment. In order to combat chemotherapy-resistance in cervical cancer and improve treatment effect, we design a CRISPR/Cas9 nanoeditor to knock out two key oncogenes E6 and E7 that lead to drug tolerance. Meanwhile, the deletion of these two oncogenes can effectively reactivate p53 and pRB signaling pathways that inhibit the growth of tumor cells. Our results demonstrated the nanoeditor could simultaneously delete two oncogenes, and the size of DNA fragments knocked out reaches an unprecedented 563 bp. After the preparation of cationic liposomes combined with chemotherapy drug docetaxel (DOC), this nanosystem can significantly inhibit the drug tolerance of cancer cells and improve the therapeutic effect of cervical cancer. Therefore, this study provides a promising strategy for the treatment of cervical cancer by combining chemotherapy and double-target gene therapy. This strategy can also be applied in other disease models to customize personalized anti-tumor strategies by simply changing chemotherapy drugs and targeted genes.

miR‑302c‑3p and miR‑520a‑3p suppress the proliferation of cervical carcinoma cells by targeting CXCL8

The aim of the present study was to identify the differentially expressed microRNAs (miRs) in cervical carcinoma (CC) tissues and cells and to explore the function of miR-302c-3p and miR-520a-3p in the proliferation of CC cells. Potential dysregulated miRNAs in CC tissues and tumour-adjacent tissues were detected. Reverse transcription-quantitative PCR (RT-qPCR) was performed to determine the expression of miR-302c-3p, miR-520a-3p and CXCL8 in CC tissues and cell lines. The target genes of the miRNAs were predicted using miRTarBase and verified by luciferase reporter assays. RT-qPCR and western blotting were performed to measure the expression of C-X-C motif ligand (CXCL)8 after transfection. The effect on proliferation was verified by Cell Counting Kit assay and ethynyl-2-deoxyuridine staining. Flow cytometry was utilised to assess the effect on apoptosis. In the present study, miR-302c-3p and miR-520a-3p were markedly downregulated in CC cell lines compared to the normal cervical cell line H8. Functionally, overexpression of miR-302c-3p and/or miR-520a-3p inhibited proliferation and promoted the apoptosis of CC cell lines in vitro, while the knockdown of miR-302c-3p and/or miR-520a-3p had the opposite effect. Furthermore, miR-302c-3p and miR-520a-3p could both bind to CXCL8. Inhibition of CXCL8 in combination with miR-302c-3p and/or miR-520a-3p overexpression exerted proliferation-suppressive and apoptosis-stimulating effects on CC cells, whereas restoring CXCL8 attenuated the miR-302c-3p- and miR-520a-3p-induced anti-proliferative and pro-apoptotic effects. miR-302c-3p and miR-520a-3p suppress the proliferation of CC cells by downregulating the expression of CXCL8, which may provide a novel target for the treatment of CC.

Idaein chloride induced p53 dependent apoptosis in cervical cancer cells through inhibition of viral oncoproteins

Host dependent expression of early HPV oncoproteins, E6 and E7 play central role in the formation of cervical carcinoma. Presently, we have shown that the cyanidin analog, idaein chloride treatment induced dose dependent apoptosis (IC50 = 2.579 μg/ml) in HPV positive - HeLa cells. Flow cytometric analysis showed arrest of cell cycle at G1 phase with an increased sub G1 cell population on 12th h of exposure. The recorded reduced expression levels of cell cycle proteins - cyclin D, cdk 4 and cdk 6 confirmed the occurrence of cell cycle arrest at G1 phase. In addition, the idaein chloride significantly inhibited the expression of E6 and E7 proteins, resulting in p53 re-expression and hence triggering of p53 dependent apoptosis. This has been further supported by the recorded variations in the expression patterns of p21/WAF, pRb and E2F regulatory proteins. In case of mitochondrial apoptotic markers, the expression of Bax was restored and Bcl-2 level got decreased at 12th h. Cleaved caspases 3 & 9 and PARP were also observed after 3 h of treatment. Interestingly, the epigenetic regulatory enzymes (DNMTs) were inhibited by idaein chloride. Thus, idaein chloride could be a potent source for developing a drug against cervical carcinoma.

Isolation and characterization of an RNA aptamer for the HPV-16 E7 oncoprotein

BACKGROUND AND AIMS

Cervical cancer is a common neoplastic disease affecting women worldwide. Expression of human papillomavirus type 16 (HPV-16) E6/E7 genes is frequently associated with cervical cancer, representing ideal targets for diagnostic and therapeutic strategies. Aptamers are oligonucleotide ligands capable of binding with high affinity and specificity to relevant markers in therapeutics and disease detection. The aim of the study was to isolate an RNA aptamer specific for the HPV-16 E7 protein.

METHODS

Aptamers were selected from a randomized oligonucleotide library using a modified SELEX method and recombinant HPV-16 E7 protein. Isolated aptamers were cloned and sequenced for in silico analysis. Interaction and electromobility shift assays (EMSA) were performed to establish aptamer specificity and affinity for E7. RNase footprinting and serial deletions of the aptamer and the E7 protein were made to characterize the aptamer-protein complex. Sandwich slot-blot assays were used for K(D) determination.

RESULTS

After several rounds of SELEX, an aptamer (G5α3N.4) exhibited specificity for E7 using cell-free and protein extracts. G5α3N.4 binding yielded a K(D) comparable to aptamers directed to other small targets. Enzymatic and genetic analysis of G5α3N.4 binding showed a secondary structure with two stem-loop domains joined by single-stranded region contacting E7 in a clamp-like manner. The G5α3N.4 aptamer also produced specific complexes in HPV-positive cervical carcinoma cells.

CONCLUSIONS

The affinity and specificity of G5α3N.4 binding domains for the HPV-16 E7 protein may be used for the detection of papillomavirus infection and cervical cancer.

Human papillomavirus: gene expression, regulation and prospects for novel diagnostic methods and antiviral therapies

Human papillomaviruses (HPVs) cause diseases ranging from benign warts to invasive tumors. A subset of these viruses termed 'high risk' infect the cervix where persistent infection can lead to cervical cancer. Although many HPV genomes have been sequenced, knowledge of virus gene expression and its regulation is still incomplete. This is due in part to the lack, until recently, of suitable systems for virus propagation in the laboratory. HPV gene expression is polycistronic initiating from multiple promoters. Gene regulation occurs at transcriptional, but particularly post-transcriptional levels, including RNA processing, nuclear export, mRNA stability and translation. A close association between the virus replication cycle and epithelial differentiation adds a further layer of complexity. Understanding HPV mRNA expression and its regulation in the different diseases associated with infection may lead to development of novel diagnostic approaches and will reveal key viral and cellular targets for development of novel antiviral therapies.

DNA nanomedicine: Engineering DNA as a polymer for therapeutic and diagnostic applications

Nanomedicine, the application of nanotechnology to medicine, encompasses a broad spectrum of fields including molecular detection, diagnostics, drug delivery, gene regulation and protein production. In recent decades, DNA has received considerable attention for its functionality and versatility, allowing it to help bridge the gap between materials science and biological systems. The use of DNA as a structural nanoscale material has opened a new avenue towards the rational design of DNA nanostructures with different polymeric topologies. These topologies, in turn, possess unique characteristics that translate to specific therapeutic and diagnostic strategies within nanomedicine.

Inhibition of metastasis-associated lung adenocarcinoma transcript 1 in CaSki human cervical cancer cells suppresses cell proliferation and invasion

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is suggested to be a long (~7 kb) non-coding RNA. MALAT1 is overexpressed in many human carcinomas, but its function remains unknown. To investigate the role of MALAT1 in human cervical cancer progression, we designed and used short hairpin RNA to inhibit MALAT1 expression in CaSki cells and validated its effect on cell proliferation and invasion. Changes in gene expression were analyzed by reverse transcriptase- polymerase chain reaction. Our data demonstrated that MALAT1 was involved in cervical cancer cell growth, cell cycle progression, and invasion through the regulation of gene expression, such as caspase-3, -8, Bax, Bcl-2, and BclxL, suggesting that MALAT1 could have important implications in cervical cancer biology. Our findings illustrate the biological significance of MALAT1 in cervical cancer progression and provide novel evidence that MALAT1 may serve as a therapeutic target in the prevention of human cervical cancer.

Inhibition of ADP-ribosylation factor-like 6 interacting protein 1 suppresses proliferation and reduces tumor cell invasion in CaSki human cervical cancer cells

ADP-ribosylation factor-like 6 interacting protein 1 (ARL6IP1) is an apoptotic regulator. To investigate the role of ARL6IP1 in human cervical cancer progression, we designed and used short hairpin RNA (shRNA) to inhibit ARL6IP1 expression in CaSki cells and validated its effect on cell proliferation and invasion. Changes in gene expression were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) or western blot. Down-regulation of ARL6IP1 expression by infection with ARL6IP1-specific RNAi-expressing vector inhibited CaSki cell proliferation and colony formation. In addition, down-regulation of ARL6IP1 expression arrested CaSki cell cycling at the G0/G1 phase and mitigated CaSki cell migration, determined by wound healing assays. ARL6IP1 was involved in cervical cancer cell growth, cell cycle progression, and invasion through regulation of gene expression, such as Caspase-3, Caspase-9, p53, TAp63, NF-κB, MAPK, Bcl-2, and Bcl-xL, suggesting that ARL6IP1 could have important implications in cervical cancer biology. Our findings illustrate the biological significance of ARL6IP1 in cervical cancer progression, and provide novel evidence that ARL6IP1 may serve as a therapeutic target in the prevention of human cervical cancer.

Dendrosome-based delivery of siRNA against E6 and E7 oncogenes in cervical cancer

Although small interfering RNA (siRNA) treatment holds great promise for the treatment of cancers, the field has been held back by the availability of suitable delivery vehicles. For cervical cancer the E6 and E7 oncogenes are ideal siRNA targets for treatment. The purpose of the present study was to explore the potential of dendrosomes for the delivery of siRNA targeting E6 and E7 proteins of cervical cancer cells in vitro. Optimization of dendrimer generation and nitrogen-to-phosphate (N/P) ratio was carried out using dendrimer-fluorescein isothiocyanate oligo complexes. The optimized N/P ratios were used in formulating complexes between dendrimers and siRNA targeting green fluorescence protein (siGFP). Although formulation 4D100 (dendrimer-siRNA complex) displayed the highest GFP knockdown, it was also found to be highly toxic to cells. In the final formulation 4D100 was encapsulated into dendrosomes so as to mask these toxic effects. The optimized dendrosomal formulation (DF), DF3 was found to possess a siGFP-entrapment efficiency of 49.76% +/- 1.62%, vesicle size of 154 +/- 1.73 nm, and zeta potential of +3.21 +/- 0.07 mV. The GFP knockdown efficiency of DF3 (dendrosome) was found to be almost identical to that of 4D100, but the former was completely nontoxic to the cells. DF3 containing siRNA against E6 and E7 was found to knock down the target genes considerably, as compared with the other formulations tested. Our results imply that dendrosomes hold potential for the delivery of siRNA and that a suitable targeting strategy could be useful for applications in vivo.

FROM THE CLINICAL EDITOR

siRNA treatment holds great promise for the treatment of cancers, but overall, the availability of suitable delivery vehicles remains a major issue. The purpose of this study was to explore the potential of dendrosomes for the delivery of siRNA targeting specific proteins in cervical cancer cells in vitro. The results suggest that dendrosomes hold potential for the delivery of siRNA and a suitable targeting strategy could be useful for applications in vivo.

No relationship observed between human p53 codon-72 genotype and HPV-associated cervical cancer in a population group with a low arginine-72 allele frequency

Infection with high-risk human papillomavirus (HR-HPV) is a necessary but not a sufficient event in the development of cervical cancer, as most infections regress without intervention. Thus, genetic host factors and cellular immune responses could be potential modifiers for the risk of developing cervical cancer. In particular, p53 is considered as the most critical tumour suppressor gene and is involved in regulating cell division. The polymorphism on p53, which encodes either a proline or an arginine amino acid residue at codon 72, has been reported as a possible risk factor for cervical disease. This polymorphism has been shown to differentially affect the efficiency of degradation of p53 protein mediated by HR-HPV E6 oncoprotein. Women with histologically proven cancer of the cervix (n = 111) and hospital-based controls (n = 143) were included in this study. The patients and controls were from the Western Cape Province in South Africa. Genotyping of the p53 polymorphism was conducted using polymerase chain reaction and restriction fragment-length polymorphism method. The distributions of the allelic frequencies were stratified in both patients and controls into two South African ethnic population groups. In this study, we observed no association between the distribution of p53 polymorphism and susceptibility to cervical cancer in the Western Cape Province populations (P = 0.466). However, the frequency of the Pro/Pro residue at codon 72 was increased in the South African population when compared to Caucasians, Indians and Portuguese population groups. Notably, as the distribution of the Pro/Pro at codon 72 of p53 gene was significantly different (P < 0.05) between the control groups of South Africa and other population groups. This result suggests that ethnic disparity may influence the levels of p53 produced.

Effect of combined antisense oligodeoxynucleotides directed against the human papillomavirus type 16 on cervical carcinoma cells

BACKGROUND

Cervical cancer is highly associated with human papillomavirus (HPV) E6 and E7 gene expression. We have previously reported two antisense oligodeoxynucleotides (AS-ODNs) directed against adjacent targets within the HPV-16 E6/E7 mRNA (419 and 434), each able to downregulate HPV-16 E6/E7 mRNA in vitro and in vivo and to specifically inhibit tumor cell growth in culture and animal models.

METHODS

Towards potential clinical application and improved in vivo performance, we analyzed the effect of the combined treatment of 419-434 AS-ODNs on the anchorage independent growth (AIG) of HPV-16-positive cervical carcinoma cell lines.

RESULTS

We found similar responses between combined 419-434 and individual AS-ODNs treatments in RNaseH assays, cell uptake, and in vivo degradation of HPV-16 E6/E7 transcripts. Moreover, the combined use of 419-434 AS-ODNs resulted in additive AIG inhibition of CaSki and SiHa cells, similar to that obtained with equivalent doses of the individual AS-ODNs.

CONCLUSIONS

By using a combined treatment, it may be possible to overcome the potential mutations frequently reported within HPV-16 genome, thus improving the potential application of 419 and 434 AS-ODNs as a therapeutic alternative for cervical cancer.

Rabbits immunised with recombinant BCG expressing the cottontail rabbit papillomavirus (CRPV) L2E7E2 genes induces regression of established papillomas

We previously demonstrated in a cottontail rabbit papillomavirus (CRPV) challenge model that recombinant Bacille Calmette-Guerin (rBCG) could potentially be used as a prophylactic vaccine vehicle to deliver papillomavirus proteins. In this study we investigated whether regression of CRPV-induced papillomas could be achieved following immunisation of out-bred New Zealand White rabbits with rBCG expressing CRPVL2, CRPVE2, CRPVE7 or CRPVL2E7E2 proteins. Rabbits immunised with rBCG/CRPVL2E7E2 had papillomas that were largely suppressed and were significantly smaller compared to the rBCG negative control group (P</=0.01). In addition, four of the six rabbits immunised with rBCG/CRPVL2E7E2 had papillomas that completely regressed 1.5 weeks post third immunisation. Rabbits immunised with rBCG/CRPVL2, rBCG/CRPVE7, or rBCG/CRPVE2 had papillomas that were significantly smaller than the negative control rabbits (P</=0.05). The findings in this study suggest that BCG could probably be used as a vaccine delivery vehicle for human papillomavirus proteins as a possible therapeutic vaccine.

Antisense RNA directed to the human papillomavirus type 16 E7 mRNA from herpes simplex virus type 1 derived vectors is expressed in CaSki cells and downregulates E7 mRNA

BACKGROUND

Human papillomavirus (HPV) infection is known to be the most important etiologic factor of cervical cancer. There is no HPV specific therapy available for treatment of invasive squamous cell carcinoma of the cervix and its precursor lesions. The present study elucidates the potential to use herpes simplex virus (HSV) derived vectors for expression of antisense RNA to HPV -16 E7 oncogene.

RESULTS

We have constructed replication competent, nonneuroinvasive HSV-1 vectors, deleted of the gamma134.5 gene. The vectors express RNA antisense to the first 100 nucleotides of the HPV-16 E7 gene. We assayed the ability of the antisense E7 vectors R5225 (tk-) and R5226 (tk+), to produce antisense RNA, as well as the consequent effects on E7 mRNA and protein levels in HPV-16 positive CaSki cells. Anti-E7 RNA was expressed by both constructs in a dose-dependent manner. Expression of HPV-16 E7 mRNA was downregulated effectively in CaSki cells infected with the tk- recombinant R5225 or with R5226. The tk+ recombinant R5226 was effective in downregulating E7 protein expression.

CONCLUSION

We have shown that anti-E7 RNA expressed from an HSV vector could efficiently downregulate HPV-16 E7 mRNA and E7 protein expression in CaSki cells. We conclude that HSV vectors may become a useful tool for gene therapy of HPV infections.

Intrabody strategies for the treatment of human papillomavirus-associated disease

Human papillomaviruses (HPVs) are associated with a variety of epithelial lesions, including benign genital warts and cervical intraepithelial neoplasia. Both cause significant morbidity in the general population, with cervical intraepithelial neoplasia progressing to cervical cancer in a subset of women who cannot resolve their infection. At present, there are no antiviral agents for the treatment of genital HPV infections, with many lesions requiring surgical intervention. Although other approaches are available for the treatment of genital warts, HPV infection cannot usually be cured and lesion recurrence is often a problem. A growing understanding of the molecular biology of HPV infection has identified several viral protein functions that may serve as drug targets. Among these are the HPV E1 and E2 proteins, which are necessary for viral genome replication and partitioning, and the E6 and E7 proteins, which are necessary for cell proliferation and apoptotic inhibition. With the exception of E1, these proteins lack enzymatic activity and achieve their effects by interacting with cellular proteins. Protein-protein interactions are in general quite difficult to inhibit using conventional small molecule drugs, but are amenable to inhibition using intracellular antibodies or intrabodies, which bind the viral proteins and sterically inhibit their association with cellular partners. The lack of homology between viral and cellular proteins, and the fact that HPV infections can be treated topically, makes them particularly well suited to the intrabody approach. This review covers the various strategies that are being considered for the treatment of HPV infections and the different intrabody formats that have been used to inhibit HPV function in model systems. The clinical utility of the approach is considered alongside the general difficulties of using protein molecules as intracellular therapeutics.

Short-interfering RNA-mediated silencing of proliferating cell nuclear antigen inhibit proliferation and induce apoptosis in HeLa cells

Proliferating cell nuclear antigen (PCNA) is an important protein for DNA polymerase delta in the nucleus, and shown to have a fundamental role in cellular proliferation. It is overexpressed to support cell growth in cervical carcinoma. To study its role in stress response, we design and use short hairpin RNA (shRNA) to inhibit PCNA expression in HeLa cells and validate its effect on cell proliferation. In this study, three PCNA-shRNA expression vectors are constructed and introduced into HeLa cells, and the cell cycle is analyzed by flow cytometry. Apoptotic cell is detected by single cell gel electrophoresis assay (comet assay), and caspase cleavage is studied also. Expression of PCNA is assessed by real-time reverse transcription-polymerase chain reaction and Western blot analysis. Upon transient transfection with plasmid encoding shRNA, it is found that expression of PCNA decreased in shRNA-transfected cells, downregulation of PCNA inhibit cell growth and induce apoptosis in HeLa cells. PCNA downregulation also increase cell population in the G0-G1 phase. In conclusion, our findings demonstrate that shRNA can inhibit the DNA replication and induce apoptosis in HeLa cells effectively and, therefore, could be used as a new potential anticancer tool for therapy of human cervical carcinoma.

Role of human papillomavirus in the etiology of head and neck cancer

Head and neck cancer is the world's sixth most common cancer, but despite advances in treatment, there has been no significant decline in the mortality rate. In recent years, there has been mounting epidemiologic and experimental evidence of a role for human papillomavirus (HPV) as the etiologic agent of a subset of head and neck cancers. The association is strongest for oropharyngeal cancers, especially those of the tonsil. HPV 16 is invariably the predominant type. HPV-positive cancers have been shown to be biologically distinct, clustering among nonsmokers and light drinkers, and have been associated with a favorable prognosis. This review examines the current findings of HPV in head and neck cancers and discusses implications for developing new treatments.

A DNA vaccine constructed with human papillomavirus type 16 (HPV16) E7 and E6 genes induced specific immune responses

OBJECTIVE

Cervical cancer is found highly associated with human papillomaviruses type 16 (HPV16). HPV16 E6 and E7 oncogenes are important transforming genes which have become the main focus of anti-cervical cancer therapy. In this study, a recombinant DNA vaccine candidate, termed HPV16-DNA-E6E7, constructed with HPV16 E7 and E6 genes was generated and used to against HPV16-induced tumors.

METHODS

We inserted an E7 DNA fragment into E6 gene to produce a recombinant gene (E6E7-DNA). The E6E7-DNA gene was inserted into a mammalian expression vector, pcDNA 3.1+, to construct the DNA vaccine candidate. Animals (C57BL/6 mice) were immunized with the vaccine candidate with various concentrations (50 microg, 100 microg or 200 microg, respectively), and cytotoxicity measurement and tumor protection assay were carried out to examine the immunological effects of the vaccine candidate.

RESULTS

Immunization of with HPV16-E6E7-DNA induced HPV16-specific immune response and also conveyed protection against TC-1 induced tumor in vivo. A survival rate (90%) after 45 days of tumor challenge was observed. The animals injected with a higher dosage of the vaccine (200 microg) exhibited prolonged survival duration of more than 55 days. No transforming activity of the vaccine candidate was detected, as determined by focus formation and degradation of endogenous p53.

CONCLUSION

Our results demonstrated that the HPV16-E6E7-DNA compound might become a candidate for HPV16 precautionary and immunotherapy.

Targeting the heat shock factor 1 by RNA interference: a potent tool to enhance hyperthermochemotherapy efficacy in cervical cancer

Carcinoma of the uterine cervix is one of the highest causes of mortality in female cancer patients worldwide, and improved treatment options for this type of malignancy are highly needed. Local hyperthermia has been successfully used in combination with systemic administration of cisplatin-based chemotherapy in phase I/II clinical studies. Heat-induced expression of cytoprotective and antiapoptotic heat shock proteins (HSP) is a known complication of hyperthermia, resulting in thermotolerance and chemoresistance and hindering the efficacy of the combination therapy. Heat shock transcription factor 1 (HSF1) is the master regulator of heat-induced HSP expression. In the present report, we used small interfering RNA (siRNA) to silence HSF1 and to examine the effect of HSF1 loss of function on the response to hyperthermia and cisplatin-based chemotherapy in HeLa cervical carcinoma. We have identified the 322-nucleotide to 340-nucleotide HSF1 sequence as an ideal target for siRNA-mediated HSF1 silencing, have created a pSUPER-HSF1 vector able to potently suppress the HSF1 gene, and have generated for the first time human cancer cell lines with stable loss of HSF1 function. We report that, although it surprisingly does not affect cancer cell sensitivity to cisplatin or elevated temperatures up to 43 degrees C when administered separately, loss of HSF1 function causes a dramatic increase in sensitivity to hyperthermochemotherapy, leading to massive (>95%) apoptosis of cancer cells. These findings indicate that disruption of HSF1-induced cytoprotection during hyperthermochemotherapy may represent a powerful strategy to selectively amplify the damage in cancer cells and identify HSF1 as a promising therapeutic target in cervical carcinoma.

Papillomavirus and treatment

Human papillomaviruses (HPVs) are small DNA viruses responsible for a broad range of clinical presentations, characterized histologically by the proliferation of epithelial cells. HPVs are responsible for benign as well as malignant lesions, the most frequent of the latter being cervical carcinoma. A better knowledge of the immunobiology of these lesions allowed the development of prophylactic vaccines (for the most frequent genital types) that are presently under evaluation. The present paper describes different approaches for the treatment of HPV lesions, still mostly based on surgery, and underlines the importance of developing adjuvant therapies.

Inhibition of cervical cancer cell growth in vitro and in vivo with lentiviral-vector delivered short hairpin RNA targeting human papillomavirus E6 and E7 oncogenes

In this study, we investigated the suppressive effect of a short hairpin RNA delivered by a lentiviral vector (LV-shRNA) against human papillomavirus (HPV) type 18 E6 on the expression of the oncogenes E6 and E7 in cervical cancer HeLa cells both in vitro and in vivo. The LV-shRNA effectively delivered the shRNA to HeLa cells and lead to a dose-dependent reduction of E7 protein and the stabilization of E6 target proteins, p53 and p21. Low-dose infection of HeLa cells with LV-shRNA caused reduced cell growth and the induction of senescence, whereas a high-dose infection resulted in specific cell death via apoptosis. Transplant of HeLa cells infected with a low dose of LV-shRNA into Rag-/- mice significantly reduced the tumor weight, whereas transplant of cells infected with a high dose resulted in a complete loss of tumor growth. Systemic delivery of LV-shRNA into mice with established HeLa cell lung metastases led to a significant reduction in the number of tumor nodules. Our data collectively suggest that lentiviral delivery is an effective way to achieve stable suppression of E6/E7 oncogene expression and induce inhibition of tumor growth both in vitro and in vivo. These results encourage further investigation of this form of RNA interference as a promising treatment for cervical cancer.

Identification of inhibitors to papillomavirus type 16 E6 protein based on three-dimensional structures of interacting proteins

Human papillomaviruses (HPV) cause cutaneous and genital warts. A subset of HPV types is associated with a high-risk for progression to malignancy. The E6 protein from the high-risk HPV types represents an attractive target for intervention because of its roles in viral propagation and cellular transformation. E6 functions in part by interaction with human cellular proteins, several of which possess a helical E6-binding motif. The role for each amino acid in this motif for binding E6 has been tested through structure determination and site-directed mutagenesis. These structural and molecular biological approaches defined the spatial geometry of functional groups necessary for binding to E6. This E6-binding information (the E6-binding pharmacophore) was transferred into a three-dimensional query format suitable for computational screening of large chemical databases. Compounds were identified and tested using in vitro and cell culture-based assays. Several compounds selectively inhibited E6 interaction with the E6-binding protein E6AP and interfered with the ability of E6 to promote p53 degradation. Such compounds provide leads for the development of new pharmacologic agents to treat papillomavirus infections and their associated cancers.