Evolutionary analysis of JC polyomavirus in Misiones' population yields insight into the population dynamics of the early human dispersal in the Americas.

BACKGROUND: JC polyomavirus (JCV) has an ethno-geographical distribution across human populations. OBJECTIVE: Study the origins of the population of Misiones (Argentina) by using JCV as genetic marker. METHODS: Viral detection and characterization was conducted by PCR amplification and evolutionary analysis of the intergenic region sequences. RESULTS: 22 out of 121 samples were positive for JCV, including 5 viral lineages: MY (n = 8), Eu-a (n = 7), B1-c (n = 4), B1-b (n = 2) and Af2 (n = 1). MY sequences clustered within a branch of Native American origin that diverged from its Asian counterpart about 21,914 years ago (HPD 95% interval 15,383-30,177), followed by a sustained demographic expansion around 5000 years ago. CONCLUSIONS: JCV in Misiones reflects the multiethnic origin of the current population, with an important Amerindian contribution. Analysis of the MY viral lineage shows a pattern consistent with the arrival of early human migrations to the Americas and a population expansion by the pre-Columbian native societies.

Genetic Variability in the E6/E7 Region of Human Papillomavirus 16 in Women from Ecuador.

Human Papillomavirus (HPV) infection is associated with intraepithelial neoplasia and cervical cancer (CC). Ecuador has a high prevalence of cervical cancer, with more than 1600 new cases diagnosed annually. This study aimed to analyze oncogenes E6 and E7 of HPV16 in samples collected from women with cancerous and precancerous cervical lesions from the Ecuadorian coast. Twenty-nine women, including six with ASCUS, three with LSIL, thirteen with HSIL, and seven with Cacu, were analyzed. The most common SNPs were E6 350G or L83V (82.6%) and E6 145T/286A/289G/335T/350G or Q14H/F78Y/L83V (17.4%). Both variants are reported to be associated with an increased risk of cervical cancer in worldwide studies. In contrast, all E7 genes have conserved amino-acid positions. Phylogenetic trees showed the circulation of the D (26.1%) and A (73.9) lineages. The frequency of D was higher than that reported in other comparable studies in Ecuador and Latin America, and may be related to the ethnic composition of the studied populations. This study contributes to the characterization of the potential risk factors for cervical carcinogenesis associated with Ecuadorian women infected with HPV16.

Genetic variation in the E6 and E7 genes of human papillomavirus type 16 in northeastern Argentina.

The province of Misiones is considered a region with a high mortality rate due to cervical cancer (CC). To gain insight into this problem, we explored the association between genetic variation in the E6 and E7 oncogenes of HPV16 and the risk of CC. We studied 160 women with cytological diagnoses of negative for intraepithelial lesion or malignity, low-grade squamous intraepithelial lesion, and high-grade squamous intraepithelial lesion/CC and a positive test for HPV16 infection. The genetic characterization of E6 and E7 genes was undertaken through PCR amplification and direct Sanger sequencing. Phylogenetic classification was conducted using Bayesian methods. To estimate the odds ratio (OR) for an association between genetic variants in the E6 and E7 genes and the risk of CC, we used ordinal logistic regression adjusted by age. The final data set comprised 112 samples. Diagnostic single-nucleotide polymorphisms (SNPs) and phylogenetic trees confirmed the presence of Lineage A (95.5%) and D (4.5%) in the samples. For the E6 gene, we identified eleven different sequences, with the most common ones being Lineage A E6 350G (58.9%) and E6 350T (37.5%). The E6 350G was associated with progression to HSIL/CC, with an OR of 19.41 (4.95-76.10). The E7 gene was more conserved than E6, probably due to the functional constraints of this small protein. Our results confirmed the association of the E6 350G SNP with a higher risk of developing CC. These data will contribute to understanding the biological bases of CC incidence in this region.

Genetic diversity of the JC polyomavirus (JCPyV) and mitochondrial DNA ancestry in Misiones, Argentina.

BACKGROUND: The use of human and viral genetic markers offers a novel way to study human migration in multiethnic populations of Latin America. OBJECTIVES: Our goal was to characterize the genetic diversity and geographical origins of JC Polyomavirus (JCPyV) and the genetic ancestry of mitochondrial DNA (mtDNA) in inhabitants from 25 de Mayo, Misiones-Argentina, a small village of largely German ancestry located close to the border with Brazil. We also evaluated the extent of agreement between viral and mtDNA markers for the different ancestry components of this population. STUDY DESIGN: 68 individuals were analyzed for JCPyV and mtDNA diversity. JCPyV detection and typing was conducted in urine samples by PCR amplification, sequencing and phylogenetic analysis of the VP1 gene. mtDNA ancestry was assessed through HVS1 sequencing, with the resulting haplotypes being classified into haplogroups of Amerindian, European and African origin. The distribution of JCPyV diversity and mtDNA ancestry in the population was statistically evaluated by Fisher exact test and the level of agreement of both markers at the individual level was evaluated by Cohen's kappa coefficient. RESULTS: Our analysis showed that 57.4% of the samples were positive for JCPyV. Of these, the 47.6% were Asian-American Type 2, 33.3% European Type 1 and 19.1% African Type 3 in origin. The mtDNA ancestry of the study participants was 33.3% Amerindian and 66.7% European. There was a significant difference among the distribution of JCPyV diversity and mtDNA ancestry (p = 0.009) and at the individual level there was no correlation between the distribution of the both markers (κ = 0.154, p = 0.297). CONCLUSION: The apparent incongruence between JCPyV diversity and mtDNA ancestry may reflect the original settlement process and more recent migration to 25 de Mayo, the latter involving viral spread through migrants from Brazil. Some potential limitations to our interpretations are also discussed.

Molecular epidemiology and phylogenetic analysis of human papillomavirus infection in women with cervical lesions and cancer from the coastal region of Ecuador / Epidemiología molecular y análisis filogenético de la infección por el virus del papiloma humano en mujeres con lesiones cervicales y cáncer en la región litoral del Ecuador

The aim of the present study was to gather information regarding the molecular epidemiology of Human papillomavirus (HPV) and related risk factors in a group of women with low- and high-grade cervical lesions and cancer from the coastal region of Ecuador. In addition, we studied the evolution of HPV variants from the most prevalent types and provided a temporal framework for their emergence, which may help to trace the source of dissemination within the region. We analyzed 166 samples, including 57 CIN1, 95 CIN2/3 and 14 cancer cases. HPV detection and typing was done by PCR-sequencing (MY09/MY11). HPV variants and estimation of the time to most recent common ancestor (tMRCA) was assessed through phylogeny and coalescence analysis. HPV DNA was found in 54.4% of CIN1, 74.7% of CIN2/3 and 78.6% of cancer samples. HPV16 (38.9%) and HPV58 (19.5%) were the most prevalent types. Risk factors for the development of cervical lesions/cancer were the following: three or more pregnancies (OR = 4.3), HPV infection (OR = 3.7 for high-risk types; OR = 3.5 for HPV16), among others. With regard to HPV evolution, HPV16 isolates belonged to lineages A (69%) and D (31%) whereas HPV58 isolates belonged only to lineage A. The period of emergence of HPV16 was in association with human populations (tMRCA = 91 052 years for HPV16A and 27000 years for HPV16D), whereas HPV58A preceded Homo sapiens evolution (322 257 years). This study provides novel data on HPV epidemiology and evolution in Ecuador, which will be fundamental in the vaccine era.

El objetivo del presente estudio fue aportar información sobre la epidemiología molecular del virus del papiloma humano (human papillomavirus [HPV]) y los factores de riesgo asociados al desarrollo de lesiones cervicales y cáncer en mujeres de la costa del Ecuador. Además, se estudiaron la evolución de las variantes de los HPV más prevalentes y el marco temporal de su emergencia, para ayudar a rastrear la fuente de dispersión en la región. Se analizaron 166 muestras, incluyendo 57 y 95 casos de neoplasia intraepitelial cervical tipo 1 (CIN1) y tipo 2/3 (CIN2/3), respectivamente, y 14 de casos de cáncer. La detección/tipificación de HPV se realizó por PCR-secuenciación (MY09/MY11). La caracterización de variantes y la datación del ancestro común más reciente (tMRCA) se realizaron mediante filogenia y coalescencia. Se encontró ADN de HPV en el 54,4% de las muestras de CIN1, el 74,7% de las muestras de CIN2/3 y el 78,6% de las muestras de cáncer. Los tipos HPV16 (38,9%) y HPV58 (19,5%) fueron los más frecuentes. Los factores de riesgo para el desarrollo de lesiones cervicales/cáncer fueron 3 o más embarazos (OR = 4,3) e infección por HPV (O = 3,7 para HPV de alto riesgo, OR = 3,5 para HPV16), entre otros. En cuanto a la evolución viral, los aislados del HPV16 pertenecían a los linajes A (69%) y D (31%), mientras que los aislados del HPV58 pertenecían únicamente al linaje A. El período de emergencia del HPV16 estuvo asociado a poblaciones humanas (tMRCA = 91.052 años para HPV16Ay 27.000 para HPV16D), mientras que el del HPV58A precedió a la evolución de Homo sapiens (322.257 años). Este estudio proporciona datos novedosos sobre la epidemiología y la evolución del HPV en Ecuador, los cuales serán fundamentales en la era de la vacuna.

Estudios sobre el virus del papiloma humano (VPH) en el Ecuador: parte I / Studies on human papillomavirus (HPV) in Ecuador: part I

Aprovechando la realización de las XL Jornadas Nacionales de Biología Espol en la ciudad de Guayaquil, se realizó una sesión dedicada a la epidemiología del virus de papiloma humano (VPH) y del cáncer cervical. Esta sesión tuvo la participación de varios investigadores provenientes de diferentes zonas del Ecuador. El presente artículo tiene como objeto presentar un resumen de estas charlas, junto a un análisis de la información mostrada además de una reflexión sobre las preguntas que quedan aún por responder en cuanto al perfil epidemiológico de esta patología en el país.

Taking advantage of the realization of theXL National Conference on Espol Biology in the city of Guayaquil, a session was held dedicated to the epidemiology of Human Papilloma Virus (HPV) and cervical cancer. This session was attended by several researchers from different areas of Ecuador. The object of this article is to present a summary of these talks, together with an analysis of the information shown in addition to a reflection on the questions still to be answered regarding the epidemiological profile of this pathology in the country.

Mitochondrial DNA ancestry, HPV infection and the risk of cervical cancer in a multiethnic population of northeastern Argentina.

BACKGROUND: Misiones Province in northeastern Argentina is considered to be a region with a high prevalence of HPV infection and a high mortality rate due to cervical cancer. The reasons for this epidemiological trend are not completely understood. To gain insight into this problem, we explored the relationship between mitochondrial DNA (mtDNA) ancestry, HPV infection, and development of cervical lesions/cancer in women from the city of Posadas in Misiones Province. METHODS: Two hundred and sixty-one women, including 92 cases of patients diagnosed with cervical lesions and 169 controls, were analyzed. mtDNA ancestry was assessed through HVS1 sequencing, while the detection and typing of HPV infection was conducted through nested multiplex PCR analysis. Multivariate logistic regression was conducted with the resulting data to estimate the odds ratios (ORs) adjusted by socio-demographic variables. RESULTS: The study participants showed 68.6% Amerindian, 26.1% European and 5.3% African mtDNA ancestry, respectively. Multiple regression analysis showed that women with African mtDNAs were three times more likely to develop a cervical lesion than those with Native American or European mtDNAs [OR of 3.8 (1.2-11.5) for ancestry and OR of 3.5 (1.0-12.0) for L haplogroups], although the associated p values were not significant when tested under more complex multivariate models. HPV infection and the development of cervical lesions/cancer were significant for all tested models, with the highest OR values for HPV16 [OR of 24.2 (9.3-62.7)] and HPV-58 [OR of 19.0 (2.4-147.7)]. CONCLUSION: HPV infection remains a central risk factor for cervical cancer in the Posadas population. The potential role of African mtDNA ancestry opens a new avenue for future medical association studies in multiethnic populations, and will require further confirmation in large-scale studies.

Molecular epidemiology and phylogenetic analysis of human papillomavirus infection in women with cervical lesions and cancer from the coastal region of Ecuador.

The aim of the present study was to gather information regarding the molecular epidemiology of Human papillomavirus (HPV) and related risk factors in a group of women with low- and high-grade cervical lesions and cancer from the coastal region of Ecuador. In addition, we studied the evolution of HPV variants from the most prevalent types and provided a temporal framework for their emergence, which may help to trace the source of dissemination within the region. We analyzed 166 samples, including 57 CIN1, 95 CIN2/3 and 14 cancer cases. HPV detection and typing was done by PCR-sequencing (MY09/MY11). HPV variants and estimation of the time to most recent common ancestor (tMRCA) was assessed through phylogeny and coalescence analysis. HPV DNA was found in 54.4% of CIN1, 74.7% of CIN2/3 and 78.6% of cancer samples. HPV16 (38.9%) and HPV58 (19.5%) were the most prevalent types. Risk factors for the development of cervical lesions/cancer were the following: three or more pregnancies (OR=4.3), HPV infection (OR=3.7 for high-risk types; OR=3.5 for HPV16), among others. With regard to HPV evolution, HPV16 isolates belonged to lineages A (69%) and D (31%) whereas HPV58 isolates belonged only to lineage A. The period of emergence of HPV16 was in association with human populations (tMRCA=91052 years for HPV16A and 27000 years for HPV16D), whereas HPV58A preceded Homo sapiens evolution (322257 years). This study provides novel data on HPV epidemiology and evolution in Ecuador, which will be fundamental in the vaccine era.

Molecular epidemiology of hepatitis B virus in Misiones, Argentina.

Hepatitis B virus (HBV) infection is a major public health problem worldwide. The aims of this study were to describe the molecular epidemiology of HBV in the Province of Misiones, Argentina and estimate the phylodynamic of the main groups in a Bayesian coalescent framework. To this end, partial or complete genome sequences were obtained from 52 blood donor candidates. The phylogenetic analysis based on partial sequences of S/P region showed a predominance of genotype D (65.4%), followed by genotype F (30.8%) and genotype A as a minority (3.8%). At subgenotype level, the circulation of subgenotypes D3 (42.3%), D2 (13.5%), F1b (11.5%) and F4 (9.6%) was mainly identified. The Bayesian coalescent analysis of 29 complete genome sequences for the main groups revealed that the subgenotypes D2 and D3 had several introductions to the region, with ancestors dating back from 1921 to 1969 and diversification events until the late '70s. The genotype F in Misiones has a more recent history; subgenotype F4 isolates were intermixed with sequences from Argentina and neighboring countries and only one significant cluster dated back in 1994 was observed. Subgenotype F1b isolates exhibited low genetic distance and formed a closely related monophyletic cluster, suggesting a very recent introduction. In conclusion, the phylogenetic and coalescent analyses showed that the European genotype D has a higher circulation, a longer history of diversification and may be responsible for the largest proportion of chronic HBV infections in the Province of Misiones. Genotype F, especially subgenotype F1b, had a more recent introduction and its diversification in the last 20years might be related to its involvement in new transmission events.

Genetic characterization and clinical implications of human papillomavirus type 16 (HPV16) variants from northeastern Argentina.

BACKGROUND: Human papillomavirus type 16 (HPV16) plays a central role in the development of cervical cancer. Worldwide studies indicate the existence of HPV16 variants that show different geographic distributions and oncogenic potential. OBJECTIVE: Our goal was to describe the genetic variation of HPV16 isolates identified in urban women with different grades of cervical lesions living in northeastern Argentina. STUDY DESIGN: We analyzed 116 HPV16-positive cervical samples (16 NLIM, 62 L-SIL, 16 H-SIL and 22 cervical cancer) from patients attending health centers in Misiones (Argentina) during 2006-13. HPV16 isolates were genetically characterized through PCR amplification and direct sequencing of 364 bp within the long control region, and the resulting sequences classified into variants based on phylogenetic analysis (lineages A, B, C and D). A potential association between HPV16 variants and lesion grade was evaluated through an odds ratio (OR) test. A temporal framework for the origin of HPV16 variants was assessed through coalescence analysis (BEAST v 1.7.5). RESULTS: Phylogenetic analysis of HPV16 sequences showed that 92.1% of the samples clustered with lineage A, and 6.9% to lineage D. HPV16 variants from lineage D were more frequently associated with high-grade lesions and cancer (HSIL+) than lineage A variants at an OR of 13.8 (1.6-117.0). The time to most common recent ancestor (tMCRA) of all variants was 119,103 years before present (HPD 95%=48,486-197,239), a date consistent with the time frame for modern human evolution. CONCLUSION: Our results suggest that HPV16 variants from lineage D may represent an additional risk factor for the development of cervical cancer in women living in northeastern Argentina. This study provides new information about viral isolates present in Argentina that will contribute to the monitoring of HPV16 infection in the vaccine era.

Analysis of TNFα promoter SNPs and the risk of cervical cancer in urban populations of Posadas (Misiones, Argentina).

BACKGROUND: Human papillomavirus (HPV) plays a central role in cervical cancer development. However, only a small fraction of infected women develop the disease. Additional risk factors, including SNPs in immune system and cytokine genes, are likely to be important determinants. OBJECTIVE: We investigated the potential role of cytokine TNF-α promoter SNPs (TNFα-375A, TNFα-307A, TNFα-243A, and TNFα-237A) in the development of high-grade cervical lesions and cancer in urban women from Posadas (Misiones, Argentina). STUDY DESIGN: Fifty-six cases (CINIII and invasive carcinoma) and 113 age-matched controls were included in the study. HPV genotype detection was conducted by PCR. TNFα SNP genotyping was conducted through PCR amplification and direct sequencing of genomic DNA. RESULTS: We observed differences in the allelic distribution of TNFα-307A and TNFα-375A SNPs among cases and controls (p<0.05). The TNFα-307A variant was associated with cervical cancer at an OR 2.4 (CI 95% 1.1-5.4), while the TNFα-375A SNP was identified in 8.8% of the controls and none of the cases. Moreover, the TNFα-375A always occurred in association with the TNFα-237A SNP, indicating linkage disequilibrium between them. CONCLUSION: Our study suggests that the presence of the high producer allele TNFα-307A is associated with an increased risk for the development of cervical cancer in the Posadas population. We also speculate that the "protective effect" of the TNFα-375A/-237A haplotype, which was restricted to controls, may be related to HLA genes linked on chromosome 6. These findings contribute to our understanding of immune gene variation in an Argentinean population, and its role in disease susceptibility.

Human papillomavirus (HPV) detection and Papanicolaou cytology in low-resource women in Posadas city, Misiones, Argentina / Detección del virus papiloma humano (HPV) y citología de Papanicolaou en mujeres de bajos recursos de la ciudad de Posadas, Misiones, Argentina

The objective of this study was to determine the prevalence of HPV infection and cervical lesions present in women who attended a health center in a low-resource area of the city of Posadas, Misiones, Argentina. Cervical cell samples (n = 163) were processed for Papanicolaou cytology and HPV-PCR tests. Socio-cultural risk factors were estimated using the odds ratio (OR, CI 95 %). Cervical lesions were detected in 14.7 % of women. The general prevalence of HPV infection was of 38 %. The most common types among the total population were HPV-16 (9.8 %) and HPV-33 (9.3 %). HPV-16 was detected in association with 29.2 % and 6.5 % of women with and without cervical lesions, respectively, the OR being 5.3 (1.8-15.8). Risk factors for HPV-16 infection were a smoking habit and a history of previous sexually-transmitted diseases. These data are important for the implementation of prevention programs, including an appropriate introduction of vaccination and the baseline for virological surveillance in the vaccine era.

El objetivo de este estudio fue determinar la prevalencia de la infección por HPV y de lesiones cervicales en mujeres asistidas en un centro de salud situado en un área de bajos recursos de la ciudad de Posadas, Misiones, Argentina. Las muestras (n = 163) fueron examinadas mediante las pruebas de Papanicolaou y de PCR para HPV. Los factores socio-culturales de riesgo fueron identifcados mediante el cálculo de la odds ratio (OR, IC 95 %). Se detectaron lesiones cervicales en el 14,7 % de las mujeres. La prevalencia de infección por HPV fue de 38 %. Los tipos más frecuentes en la población total fueron HPV-16 (9,8 %) y HPV-33 (9,3 %). El HPV-16 se detectó asociado al 29,2 % y al 6,5 % de las mujeres con lesiones del cuello uterino y sin ellas, respectivamente, con un OR de 5,3 (1,8-15,8). Los factores de riesgo para la infección por HPV-16 fueron el hábito de fumar y el antecedente de enfermedades de transmisión sexual. Estos datos son importantes para la ejecución de los programas de prevención, incluyendo una introducción adecuada de la vacunación y la línea de base para la vigilancia virológica en la era de la vacuna.

Human papillomavirus (HPV) detection and Papanicolaou cytology in low-resource women in Posadas city, Misiones, Argentina.

The objective of this study was to determine the prevalence of HPV infection and cervical lesions present in women who attended a health center in a low-resource area of the city of Posadas, Misiones, Argentina. Cervical cell samples (n = 163) were processed for Papanicolaou cytology and HPV-PCR tests. Socio-cultural risk factors were estimated using the odds ratio (OR, CI 95 %). Cervical lesions were detected in 14.7 % of women. The general prevalence of HPV infection was of 38 %. The most common types among the total population were HPV-16 (9.8 %) and HPV-33 (9.3 %). HPV-16 was detected in association with 29.2 % and 6.5 % of women with and without cervical lesions, respectively, the OR being 5.3 (1.8-15.8). Risk factors for HPV-16 infection were a smoking habit and a history of previous sexually-transmitted diseases. These data are important for the implementation of prevention programs, including an appropriate introduction of vaccination and the baseline for virological surveillance in the vaccine era.

Loss of retinal cadherin facilitates mammary tumor progression and metastasis.

The mammary epithelium is thought to be stabilized by cell-cell adhesion mediated mainly by E-cadherin (E-cad). Here, we show that another cadherin, retinal cadherin (R-cad), is critical for maintenance of the epithelial phenotype. R-cad is expressed in nontransformed mammary epithelium but absent from tumorigenic cell lines. In vivo, R-cad was prominently expressed in the epithelium of both ducts and lobules. In human breast cancer, R-cad was down-regulated with tumor progression, with high expression in ductal carcinoma in situ and reduced expression in invasive duct carcinomas. By comparison, E-cad expression persisted in invasive breast tumors and cell lines where R-cad was lost. Consistent with these findings, R-cad knockdown in normal mammary epithelium stimulated invasiveness and disrupted formation of acini despite continued E-cad expression. Conversely, R-cad overexpression in aggressive cell lines induced glandular morphogenesis and inhibited invasiveness, tumor formation, and lung colonization. R-cad also suppressed the matrix metalloproteinase 1 (MMP1), MMP2, and cyclooxygenase 2 gene expression associated with pulmonary metastasis. The data suggest that R-cad is an adhesion molecule of the mammary epithelium, which acts as a critical regulator of the normal phenotype. As a result, R-cad loss contributes to epithelial suppression and metastatic progression.

Human papillomavirus type 16 molecular variants in Guarani Indian women from Misiones, Argentina.

OBJECTIVE: To identify human papillomavirus type 16 (HPV16) E6 and L1 molecular variants infecting Guarani Indian women settled in Misiones, Argentina, a region with a high prevalence of cervical cancer. Some intratypic molecular variants of HPV16 have been associated with greater oncogenic risk, but their implication in the etiology of cervical cancer is still uncertain. METHODS: Seventy HPV16 positive cervical samples from Guarani Indian women settled in two different areas of Misiones, Argentina, (34 from the northern area and 36 from the central area), were analyzed. Thirty-seven had normal cytology, 18 had a low-grade squamous intraepithelial lesion (LGSIL), and 15 a high-grade squamous intraepithelial lesion (HGSIL). HPV16 E6 and L1 molecular variants were identified by PCR, followed by dot blot hybridization with 23 and 12 biotinylated oligonucleotide probes, respectively. RESULTS: The frequency of HPV16 variants over the Guarani population was 51% EP (European prototype), 32% E-350G, 9% Af1-a (African 1), 4% E-6862C, 3% Af2-a, and 1% AA-a (Asian-American). The distribution of variants was not homogeneous in the two areas under analysis, with the northern area being more diverse showing 74% of European variants, while the central area presented exclusively E variants. No statistically significant association was found between any particular variant and grade of cervical lesion. CONCLUSION: This study reports for the first time HPV16 E6 and L1 molecular variants infecting women from an aboriginal community inhabiting a rainforest region of South America. The presence of E class variants could be attributed primarily to contacts with the Spanish conquerors, and Af variants from African slaves introduced later in the South American continent.

Caveolin-1 gene disruption promotes mammary tumorigenesis and dramatically enhances lung metastasis in vivo. Role of Cav-1 in cell invasiveness and matrix metalloproteinase (MMP-2/9) secretion.

Caveolin-1 (Cav-1) is the principal structural component of caveolae membrane domains in non-muscle cells, including mammary epithelia. There is now clear evidence that caveolin-1 influences the development of human cancers. For example, a dominant-negative mutation (P132L) in the Cav-1 gene has been detected in up to 16% of human breast cancer samples. However, the exact functional role of caveolin-1 remains controversial. Mechanistically, in cultured cell models, Cav-1 is known to function as a negative regulator of the Rasp42/44 MAP kinase cascade and as a transcriptional repressor of cyclin D1 gene expression, possibly explaining its in vitro transformation suppressor activity. Genetic validation of this hypothesis at the in vivo and whole organismal level has been prevented by the lack of a Cav-1 (-/-)-null mouse model. Here, we examined the role of caveolin-1 in mammary tumorigenesis and lung metastasis using a molecular genetic approach. We interbred a well characterized transgenic mouse model of breast cancer, MMTV-PyMT (mouse mammary tumor virus-polyoma middle T antigen), with Cav-1 (-/-)-null mice. Then, we followed the onset and progression of mammary tumors and lung metastases in female mice over a 14-week period. Interestingly, PyMT/Cav-1 (-/-) mice showed an accelerated onset of mammary tumors, with increased multiplicity and tumor burden ( approximately 2-fold). No significant differences were detected between PyMT/Cav-1 (+/+) and PyMT/Cav-1 (+/-) mice, indicating that complete loss of caveolin-1 is required to accelerate both tumorigenesis and metastasis. Molecularly, mammary tumor samples derived from PyMT/Cav-1 (-/-) mice showed ERK-1/2 hyperactivation, cyclin D1 up-regulation, and Rb hyperphosphorylation, consistent with dys-regulated cell proliferation. PyMT/Cav-1 (-/-) mice also developed markedly advanced metastatic lung disease. Conversely, recombinant expression of Cav-1 in a highly metastatic PyMT mammary carcinoma-derived cell line, namely Met-1 cells, suppressed lung metastasis by approximately 4.5-fold. In vitro, these Cav-1-expressing Met-1 cells (Met-1/Cav-1) demonstrated a approximately 4.8-fold reduction in invasion through Matrigel-coated membranes. Interestingly, delivery of a cell permeable peptide encoding the caveolin-1 scaffolding domain (residues 82-101) into Met-1 cells was sufficient to inhibit invasion. Coincident with this decreased invasive index, Met-1/Cav-1 cells exhibited marked reductions in MMP-9 and MMP-2 secretion and associated gelatinolytic activity, as well as diminished ERK-1/2 signaling in response to growth factor stimulation. These results demonstrate, for the first time, that caveolin-1 is a potent suppressor of mammary tumor growth and metastasis using novel in vivo animal model approaches.

Cadherin switch in tumor progression.

The loss of E-cadherin expression or function in epithelial carcinomas has long been thought as a primary reason for disruption of tight epithelial cell-cell contacts and release of invasive tumor cells from the primary tumor. Indeed, E-cadherin serves as a widely acting suppressor of invasion and growth of epithelial cancers, and its functional elimination represents a key step in the acquisition of the invasive phenotype for many tumors. Recent evidence indicates, however, that in addition to the loss of the "invasion-suppressor" E-cadherin, another adhesion molecule, N-cadherin, becomes upregulated in invasive tumor cell lines. N-cadherin was shown to be present in the most invasive and dedifferentiated breast cancer cell lines, and its exogenous expression in tumor cells induces a scattered morphology and heightened motility, invasion, and metastasis. N-cadherin cooperates with the FGF receptor, resulting in signals that lead to the up-modulation of MMP-9 and, hence, cellular invasion. In addition to a signaling function in metastasis, N-cadherin probably also supports the systemic dissemination of tumor cells by enabling circulating tumor cells to associate with the stroma and the endothelium at distant sites. Here, we summarize the various aspects of the E- to N-cadherin switching in epithelial carcinomas and its potential impact on metastatic progression.

Human papillomavirus cervical infection in Guarani Indians from the rainforest of Misiones, Argentina.

OBJECTIVE: To evaluate the prevalence of human papillomavirus (HPV) cervical infection in women from the South American Guarani Indian tribe located in the rain forest of Misiones, north-eastern Argentina; a region with a high incidence of cervical carcinoma. METHODS: A cross-sectional cytological and HPV screening of sexually active Guarani women from nine Indian settlements was conducted. Demographic data, information about sexual behavior, and gynaecological history were recorded. Fresh cervical specimens from 239 patients were collected, of which 207 were included in this study. Cytology and microbiological detection were carried out by the Papanicolaou and Gram stain methods, respectively. HPV detection and typing were analyzed by PCR and RFLP. RESULTS: Pap smears in 96% of all patients showed an inflammatory pattern. A possible etiologic agent was found in 58% of cases: 52% Trichomonas vaginalis, 35% Gardnerella vaginalis and 13% Candida sp. Seven cases had cytological changes compatible with Low Grade Intraepithelial Lesion (LGSIL), one with High Grade Intraepithelial Lesion (HGSIL) and one in situ cervical cancer. The prevalence for generic HPV infection was 64% (133/207). Genotyping gave a 26% prevalence for HPV types 16/18, 13% for types 6/11 and 30% for other types, with nine mixed infections. CONCLUSION: This work reports for the first time the prevalence of cervical HPV infection in Guarani women. Nearly all Guarani women had some grade of cervical disease. Generic HPV infection prevalence was elevated (64%), with predominance of high risk types 16/18. A large variety of viral types was detected, including high to intermediate risk types not found previously in the region.