erbB expression changes in ethanol and 7, 12- dimethylbenz (a) anthracene-induced oral carcinogenesis

Objetive: The aim of this study was to determine erbB expression in normal mucosa, oral dysplasia, and invasive carcinomas developed in the hamster's buccal pouch chemical carcinogenesis model. Study design: Fifty Syrian golden hamsters were equally divided in five groups (A-E); two controls and three experi - mental group exposed to alcohol, DMBA, or both for 14 weeks. Number of tumors per cheek, volume, histological condition, erbB expression were determined and results were analyzed by the Mann-Whitney U and Dunn's test. Results: Control groups and those exposed to alcohol (A, B and C respectively) only presented clinical and histo - logical normal mucosa; while those exposed to DMBA or DMBA plus alcohol (D and E groups) developed dys - plasia and invasive carcinomas. erbB2, erbB3, and erbB4 increased their expression in alcohol-exposed mucosa, dysplasia, and invasive carcinomas. We observed a similar expression level for erbB2 in dysplasia and carcinomas; while, erbB3 and erbB4 were similar only in carcinomas. Conclusion: The DMBA and alcohol can be considered as carcinogen and promoter for oral carcinogenesis. The erbB expression is different according to their histological condition, suggesting differential participation of the erbB family in oral carcinogenesis induced by alcohol and DMBA

Prognostic importance of DNA from human papillomavirus in patients with oral squamous cell carcinoma

Survival of patients with oral squamous cell carcinoma (OSCC) is generally low, with the likelihood of locoregional recurrence or disease progression (LR/DP). Knowledge of prognostic factors for survival is key to achieving an understanding and increased survival. The present study aimed to identify prognostic factors for patients with OSCC, especially the presence of DNA from human papillomavirus (HPV). Retrospective cohort study including 119 patients with OSCC treated at the National Cancer Institute in Mexico City (2009-2013). Clinical information was obtained from patient records including LR/DP. Formalin-fixed, paraffin-embedded tissues were obtained and used for detecting DNA from different types of HPV. Potential prognostic factors for Overall Survival (OS) were analyzed using the Cox proportional hazards model. After model adjustment, factors associated with longer OS were a pre-treatment platelet count above 400,000/mm3 (HR=0.09, p=0.026) and response to primary treatment (HR=0.26, p=0.001). HPV DNA was present in 23 (19.3%) of the patients and importantly, type 16 found in 19 of them. Although survival of HPV-positive patients was longer, difference was not significant. However, among patients with LR/DP, HPV positivity was significantly associated with increased survival (HR=0.23, p=0.034). Importantly, survival was significantly different for HPV-positive patients with LR/DP > 6 months (HR=0.20, p=0.002), had higher absolute lymphocyte count at start of treatment (HR=0.50, p=0.028) or had local rescue treatment (HR=0.24, p=0.019). Although HPV positivity was not associated with a longer OS of OSCC patients, a better prognosis was significantly associated with HPV positivity and recurring or progressing disease, particularly with HPV type 16

Cancer-initiating cells derived from established cervical cell lines exhibit stem-cell markers and increased radioresistance

<p>Abstract</p> <p>Background</p> <p>Cancer-initiating cells (CICs) are proposed to be responsible for the generation of metastasis and resistance to therapy. Accumulating evidences indicates CICs are found among different human cancers and cell lines derived from them. Few studies address the characteristics of CICs in cervical cancer. We identify biological features of CICs from four of the best-know human cell lines from uterine cervix tumors. (HeLa, SiHa, Ca Ski, C-4 I).</p> <p>Methods</p> <p>Cells were cultured as spheres under stem-cell conditions. Flow cytometry was used to detect expression of CD34, CD49f and CD133 antigens and Hoechst 33342 staining to identify side population (SP). Magnetic and fluorescence-activated cell sorting was applied to enrich and purify populations used to evaluate tumorigenicity in nude mice. cDNA microarray analysis and <it>in vitro </it>radioresistance assay were carried out under standard conditions.</p> <p>Results</p> <p>CICs, enriched as spheroids, were capable to generate reproducible tumor phenotypes in nu-nu mice and serial propagation. Injection of 1 × 10³dissociated spheroid cells induced tumors in the majority of animals, whereas injection of 1 × 10⁵monolayer cells remained nontumorigenic. Sphere-derived CICs expressed CD49f surface marker. Gene profiling analysis of HeLa and SiHa spheroid cells showed up-regulation of CICs markers characteristic of the female reproductive system. Importantly, epithelial to mesenchymal (EMT) transition-associated markers were found highly expressed in spheroid cells. More importantly, gene expression analysis indicated that genes required for radioresistance were also up-regulated, including components of the double-strand break (DSB) DNA repair machinery and the metabolism of reactive oxygen species (ROS). Dose-dependent radiation assay indicated indeed that CICs-enriched populations exhibit an increased resistance to ionizing radiation (IR).</p> <p>Conclusions</p> <p>We characterized a self-renewing subpopulation of CICs found among four well known human cancer-derived cell lines (HeLa, SiHa, Ca Ski and C-4 I) and found that they express characteristic markers of stem cell, EMT and radioresistance. The fact that CICs demonstrated a higher degree of resistance to radiation than differentiated cells suggests that specific detection and targeting of CICs could be highly valuable for the therapy of tumors from the uterine cervix.</p

Analysis of CpG methylation sites and CGI among human papillomavirus DNA genomes

<p>Abstract</p> <p>Background</p> <p>The Human Papillomavirus (HPV) genome is divided into early and late coding sequences, including 8 open reading frames (ORFs) and a regulatory region (LCR). Viral gene expression may be regulated through epigenetic mechanisms, including cytosine methylation at CpG dinucleotides. We have analyzed the distribution of CpG sites and CpG islands/clusters (CGI) among 92 different HPV genomes grouped in function of their preferential tropism: cutaneous or mucosal. We calculated the proportion of CpG sites (PCS) for each ORF and calculated the expected CpG values for each viral type.</p> <p>Results</p> <p>CpGs are underrepresented in viral genomes. We found a positive correlation between CpG observed and expected values, with mucosal high-risk (HR) virus types showing the smallest O/E ratios. The ranges of the PCS were similar for most genomic regions except <it>E4</it>, where the majority of CpGs are found within islands/clusters. At least one CGI belongs to each <it>E2/E4 </it>region. We found positive correlations between PCS for each viral ORF when compared with the others, except for the LCR against four ORFs and <it>E6 </it>against three other ORFs. The distribution of CpG islands/clusters among HPV groups is heterogeneous and mucosal HR-HPV types exhibit both lower number and shorter island sizes compared to cutaneous and mucosal Low-risk (LR) HPVs (all of them significantly different).</p> <p>Conclusions</p> <p>There is a difference between viral and cellular CpG underrepresentation. There are significant correlations between complete genome PCS and a lack of correlations between several genomic region pairs, especially those involving LCR and <it>E6</it>. <it>L2 </it>and <it>L1 </it>ORF behavior is opposite to that of oncogenes <it>E6 </it>and <it>E7</it>. The first pair possesses relatively low numbers of CpG sites clustered in CGIs while the oncogenes possess a relatively high number of CpG sites not associated to CGIs. In all HPVs, <it>E2/E4 </it>is the only region with at least one CGI and shows a higher content of CpG sites in every HPV type with an identified <it>E4</it>. The mucosal HR-HPVs show either the shortest CGI size, followed by the mucosal LR-HPVs and lastly by the cutaneous viral subgroup, and a trend to the lowest CGI number, followed by the cutaneous viral subgroup and lastly by the mucosal LR-HPVs.</p

Vaccines against human papillomavirus and perspectives for the prevention and control of cervical cancer

Today, "persistent" infections by certain types of human papillomavirus (HPV) are considered necessary for developing cervical cancer. Producing efficient vaccines against these viruses may eventually lead to a great reduction in incidence and mortality rates of this cancer. In the case of HPV, the production of traditional vaccines usually based in dead or attenuated viruses is not possible due in part to the lack of systems where large quantities of viral particles could be obtained. Fortunately, the expression of the late L1 protein alone, or in combination with L2, leads to the generation of structures resembling true virions that have been called virus-like particles (VLPs) and constitute excellent candidates as prophylactic vaccines. VLPs have shown to be very immunogenic, and have prevented development of natural or challenged infections in both animal systems and humans. Recently, HPV16 VLPs were shown to be very efficient to prevent the development of "persistent" infections, as determined by PCR assays, in a large group of vaccinated women. Therapeutic vaccines, on the other hand, are expected to have an impact on advanced lesions and residual illness, by taking advantaje of the fact that early E6 and E7 genes are thought to be constitutively expressed in cervical tumors and precursor lesions. Finally, DNA-based vaccines could represent a useful alternative for preventing infections by genital HPV

Vaccines against human papillomavirus and perspectives for the prevention and control of cervical cancer Vacunas contra virus del papiloma humano y perspectivas para la prevención y el control del cáncer cervicouterino

Today, "persistent" infections by certain types of human papillomavirus (HPV) are considered necessary for developing cervical cancer. Producing efficient vaccines against these viruses may eventually lead to a great reduction in incidence and mortality rates of this cancer. In the case of HPV, the production of traditional vaccines usually based in dead or attenuated viruses is not possible due in part to the lack of systems where large quantities of viral particles could be obtained. Fortunately, the expression of the late L1 protein alone, or in combination with L2, leads to the generation of structures resembling true virions that have been called virus-like particles (VLPs) and constitute excellent candidates as prophylactic vaccines. VLPs have shown to be very immunogenic, and have prevented development of natural or challenged infections in both animal systems and humans. Recently, HPV16 VLPs were shown to be very efficient to prevent the development of "persistent" infections, as determined by PCR assays, in a large group of vaccinated women. Therapeutic vaccines, on the other hand, are expected to have an impact on advanced lesions and residual illness, by taking advantaje of the fact that early E6 and E7 genes are thought to be constitutively expressed in cervical tumors and precursor lesions. Finally, DNA-based vaccines could represent a useful alternative for preventing infections by genital HPV.<br>Actualmente, las infecciones "persistentes" por algunos tipos del virus del papiloma humano se consideran como necesarias para desarrollar cáncer cervicouterino. Por ello, el desarrollo de vacunas eficientes contra estos virus se ha considerado de suma importancia para poder eventualmente ayudar a controlar esta enfermedad, en países donde los programas de detección oportuna no han dado aún los resultados deseados. En el caso de estos virus no es posible el desarrollo de vacunas tradicionales, las cuales están basadas generalmente en el empleo de virus atenuados o muertos. Esto debido a la falta de sistemas eficientes para producir partículas virales en cantidades suficientes para ser usadas en programas masivos. Sin embargo, de manera afortunada, la expresión de la proteína viral tardía L1, sola o en combinación con la proteína L2, lleva a la generación de estructuras similares a los viriones infectivos y que han sido denominadas "partículas semejantes a virus" o VLP. Estas preparaciones de cápsides vacías han sido probadas ya en diferentes modelos animales, incluidos los humanos. Recientemente, se ha reportado que la las VLP del virus del papiloma humano tipo 16 son capaces de prevenir el desarrollo de las infecciones "persistentes" causadas por algunos tipos del virus del papiloma humano, consideradas precursoras del cáncer cervicouterino