Risk allelic load in Th2 and Th3 cytokines genes as biomarker of susceptibility to HPV-16 positive cervical cancer: a case control study.

BACKGROUND: Alterations in the host cellular immune response allow persistent infections with High-Risk Human Papillomavirus (HR-HPV) and development of premalignant cervical lesions and cervical cancer (CC). Variations of immunosuppressive cytokine levels in cervix are associated with the natural history of CC. To assess the potential role of genetic host immunity and cytokines serum levels in the risk of developing CC, we conducted a case-control study paired by age. METHODS: Peripheral blood samples from patients with CC (n = 200) and hospital controls (n = 200), were used to evaluate nine biallelic SNPs of six cytokine genes of the adaptive immune system by allelic discrimination and cytokines serum levels by ELISA. RESULTS: After analyzing the SNP association by multivariate logistic regression adjusted by age, CC history and smoking history, three Th2 cytokines (IL-4, IL-6 and IL-10) and one Th3 (TGFB1) cytokine were significantly associated with CC. Individuals with at least one copy of the following risk alleles: T of SNP (-590C > T IL-4), C of SNP (-573G > C IL-6), A of SNP (-592C > A IL-10), T of SNP (-819C > T IL-10) and T of SNP (-509C > T TGFB1), had an adjusted odds ratio (OR) of 2.08 (95 % CI 1.475-2.934, p = 0.0001), an OR of 1.70 (95 % CI 1.208-2.404, p = 0.002), an OR of 1.87 (95 % CI 1.332-2.630, p = 0.0001), an OR of 1.67 (95 % CI 1.192-2.353, p = 0.003) and an OR of 1.91 (95 % CI 1.354-2.701, p = 0.0001), respectively, for CC. The burden of carrying two or more of these risk alleles was found to have an additive effect on the risk of CC (p trend = 0.0001). Finally, the serum levels of Th2 and Th3 cytokines were higher in CC cases than the controls; whereas IFNG levels, a Th1 cytokine, were higher in controls than CC cases. CONCLUSION: The significant associations of five SNPs with CC indicate that these polymorphisms are potential candidates for predicting the risk of development of CC, representing a risk allelic load for CC and can be used as a biomarker of susceptibility to this disease.

Molecular Mechanism and Potential Targets for Blocking HPV-Induced Lesion Development.

Persistent infection with high-risk HPV is the etiologic agent associated with the development of cervical cancer (CC) development. However, environmental, social, epidemiological, genetic, and host factors may have a joint influence on the risk of disease progression. Cervical lesions caused by HPV infection can be removed naturally by the host immune response and only a small percentage may progress to cancer; thus, the immune response is essential for the control of precursor lesions and CC. We present a review of recent research on the molecular mechanisms that allow HPV-infected cells to evade immune surveillance and potential targets of molecular therapy to inhibit tumor immune escape.

IL-10 expression is regulated by HPV E2 protein in cervical cancer cells.

It has been found that certain cytokines (IL-4, IL-10 and TGF-ß1) are highly expressed locally in biopsies from patients with premalignant lesions and cervical cancer, and may induce a local immune-suppression state. In particular, IL-10 is highly expressed in tumor cells and its expression is directly proportional to the development of HPV-positive cervical cancer, suggesting an important role of HPV proteins in the expression of IL-10. In fact, we demonstrated that E6 and E7 HPV proteins regulate TGF-ß1 gene expression in cervical cancer cells. Here, we found by band shifting analysis that the HPV E2 protein binds to the regulatory region of the human IL-10 gene (-2054 nt) and induces high promoter activity in epithelial cells. Additionally, cervical cancer cells transfected to express the HPV E2 protein induce elevated levels of IL-10 mRNA in human papillomavirus-infected cells. The elevated expression of IL-10 may allow for virus persistency, the transformation of cervical epithelial cells, and consequently cancer development.

HPV 16 E2 protein induces apoptosis in human and murine HPV 16 transformed epithelial cells and has antitumoral effects in vivo.

OBJECTIVE: Our aims were to examine the ability of the human papillomaviruse (HPV) 16 E2 protein to induce apoptosis in a murine HPV-transformed cell line, and to evaluate its antitumor properties on HPV-associated tumors in vivo in immunocompetent mice. METHODS: HPV-transformed murine BMK-16/myc cells and human SiHa cells were transfected with the HPV 16 E2 gene to examine the effects of the E2 protein on cell growth and on the E6 and E7 oncogenes as well as DNA fragmentation and activation of the extrinsic pathway of apoptosis. Finally, to test the antitumor effect of the E2 protein on an experimental mouse tumor model, we generated a recombinant adenovirus expressing the E2 protein. RESULTS: The E2 protein inhibited the growth of SiHa and BMK-16/myc cell lines, and repressed the E6 and E7 oncogenes. Moreover, the E2 protein induced DNA fragmentation and apoptosis through activation of caspases 8 and 3 in BMK-16/myc cells. On the other hand, E2 also showed antitumor effects in vivo. CONCLUSIONS: Our findings indicate that E2 exerts pro-apoptotic activity in a murine HPV-transformed cell line as well as an antitumor effect in vivo.

El paradigma inmune Th1-Th2: un vínculo entre obesidad, aterosclerosis y diabetes mellitus / The Th1-Th2 immune paradigm: a link among obesity, atherosclerosis and diabetes mellitus

Recientemente ha llamado la atención la asociación entre inflamación crónica de baja intensidad --evidenciada como elevación de la proteína C reactiva (PCR)-- y obesidad, aterosclerosis y diabetes mellitus. Hay evidencia de que esta asociación se debe a una desregulación de la respuesta inmune de linfocitos T cooperadores tipos 1 y 2, orientada hacia un perfil proinflamatorio, con aumento en la producción de interleucina (IL) 6 y de otras citocinas, como el factor de necrosis tumoral alfa, la IL-1-ß y el interferón-gamma. Esta desregulación de la respuesta inmune tiene un papel fisiopatológico crucial en la obesidad, la enfermedad aterosclerótica y la diabetes mellitus. Asimismo, podría ser el origen de las anomalías observadas en el síndrome metabólico, como la resistencia a la insulina, la hiperglucemia y la dislipidemia, debido a los efectos de las citocinas involucradas sobre el metabolismo. El conocimiento de estos mecanismos proporcionará un mejor entendimiento de la fisiopatología de las enfermedades crónicas degenerativas y puede ser la base para el planteamiento de nuevas estrategias preventivas y terapéuticas (AU)

An association between elevated C-reactive protein related to low-intensity chronic inflammation and chronic disease (obesity, atherosclerosis and diabetes mellitus) has been the focus of recent attention. A growing body of knowledge indicates that this association is due to disregulation of the Th1-Th2 immune response, with increased production of proinflammatory cytokines TNF-*, IL1-ß, IFN-* and IL-6. Such an abnormality plays a key physiopathologic role in the development of obesity, atherosclerosis and diabetes mellitus. Moreover, this proinflammatory disregulation of the immune response can lead to the insulin resistance, hyperglycemia and dyslipidemia that characterize the metabolic syndrome due to the metabolic effects of the cytokines involved. The study of these mechanisms will promote better understanding of the physiopathology of chronic diseases and could be useful for the development of new preventive and therapeutic strategies (AU)

[Transforming growth factor beta-1: structure, function, and regulation mechanisms in cancer]. / Factor de crecimiento transformante beta-1: estructura, función y mecanismos de regulación en cáncer.

Transforming growth factor beta-1 (TGF-beta 1) is produced by several cell lineages such as lymphocytes, macrophages, and dendritic cells, and its expression serves in both autocrine and paracrine modes to control the differentiation, proliferation, and state of activation of these and other cells. In general, TGF-beta 1 has pleiotropic properties on the immune response during the development of infection diseases and cancer; however, the mechanisms of action and regulation of gene expression of this cytokine are poorly understood, in this review, the biological properties and the molecular mechanisms that regulate TGF-beta 1 gene expression are described, to understand the role of this cytokine in growth and cell differentiation. The knowledge of molecular mechanisms of gene expression of TGF-beta 1 may serve to develop new cancer therapies. The English version of this paper is available at: http://www.insp.mx/salud/index.html

[Regulation of the cell cycle and the development of cancer: therapeutic prospects]. / Regulación del ciclo celular y desarrollo de cáncer: perspectivas terapéuticas.

Several genetic alterations occur during the transformation process from normal to tumor cells, that involve the loss of fidelity of processes as replication, reparation, and segregation of the genomic material. Although normal cells have defense mechanisms against cancer progression, in tumor cells different escape pathways are activated leading to tumor progression. Recent advances have permitted cancer research to focus on the identification of some of its etiological factors. The knowledge of cell cycle reveals a precise mechanism achieved by the coordinated interactions and functions of cyclin-dependent kinases, control checkpoint, and repair pathways. Furthermore, it has been demonstrated that this coordinated function can be abrogated by specific genetic changes. These findings suggest that the molecular mechanisms responsible for cellular transformation may help to identify potential targets to improve cancer therapies.

[Structure and function of the T-lymphocyte antigen receptor and its role in infectious diseases]. / Estructura y función del receptor de antígeno de linfocitos T y su papel en enfermedades infecciosas.

The T lymphocytes recognize antigens through antigen receptors (TcRs) and the major histocompatibility complex (MHC) molecules: they lysate the cells that bear the antigen, or release cytokines that are mediators of the immune response. The TcRs recognize antigens in the form of short peptides bound to MHC molecules. So far, there are two isotypes of TcR: gamma/delta and alpha/beta, which appear in the sequence during T-cell ontogeny. The process of selection of TcRs during thymic ontogeny obeys to molecular mechanisms which generate intracellular events that will participate in the gene expression of the TcR. The aim of the present paper is to review the molecular, structural, and functional aspects of the TcRs, and their role in human autoimmune infectious disease.

Regulation of gamma T-cell antigen receptor expression by intracellular calcium in acute lymphoblastic leukemia cell line DND41.

The calcium ionophore, ionomycin, promotes an increase of intracellular calcium and regulates mRNA expression of gamma/delta-TcR gene in human T lymphocytes. The mechanism of this regulation is not yet clear. Thus, the regulation by intracellular calcium requires elucidation. We studied the gamma-TcR gene expression in acute lymphoblastic leukemia cell line DND41 (CD4- CD8-) by Northern blot and flow cytometric analysis. The mRNA levels of gamma-TcR increased by ionomycin, anti-CD3, and with TPA. TPA had an antagonistic effect to both ionomycin and anti-CD3. Also, TPA inhibits the increased intracellular calcium promoted by ionomycin but not the increase promoted by anti-CD3 and ionomycin. Our results suggest that intracellular calcium induces mRNA and protein expression of gamma-TcR chain. This effect is antagonized by protein kinase C-activation. Thus, we conclude that the target cells of the differential regulation on gamma-TcR mRNA expression by intracellular calcium modulators are the CD4- CD8- cells, and this is due to cytosolic calcium mobilization.

[Molecular bases of cancer immunology]. / Bases moleculares de la inmunología del cáncer.

The immune system is a tight network of different types of cells and molecules. The coordinated action of these elements mounts a precise immune response against tumor cells. However, these cells present several escape mechanisms, leading to tumor progression. This paper shows several cellular and molecular events involved in the regulation of the immune response against tumor cells. The interaction of several molecules such as MHC, TcR, adhesins, tumor antigens and cytokines are discussed, as well as the most recent knowledge about escape mechanisms and immunotherapy.

Analysis of purine metabolic enzymes in human CD4 Leu 8- and CD4 Leu 8+ lymphocyte subpopulations.

1. Specific activities of adenosine deaminase, purine nucleoside phosphorylase, adenosine kinase, 5'-nucleotidase, S-adenosyl-L-homocysteine hydrolase, AMP deaminase, adenine phosphoribosyl transferase, and hypoxanthine phosphoribosyl transferase were analyzed in human CD4 T-lymphocyte subsets. 2. CD4 Leu 8- (helper/inducer) and CD4 Leu 8+ (suppressor/inducer) subpopulations were obtained by panning or fluorescence activated cell sorting techniques using specific monoclonal antibodies. 3. A 45% decrease of 5'-NT AMP activity in the CD4 Leu 8- cells (suppressor/inducer) compared with CD4 total cell population. 4. No statistical significant differences in enzyme activity were found between the subsets analyzed in other purine enzymes. 5. These results suggest that the distribution of purine metabolic enzymes is homogeneous in CD4 Leu 8- and CD4 Leu 8+ T-lymphocyte subpopulations.

[Infectious agents and autoimmune diseases]. / Agentes infecciosos y enfermedades autoinmunes.

In this paper the molecular aspects of the relationships between infectious agents and autoimmune diseases, the mechanisms of immune response to infectious agents, and the more recent hypotheses regarding the cause of autoimmune diseases are discussed. The antigens are processed and selected by their immunogenicity, and presented by HLA molecules to the T cell receptor. These events initiate the immune response with the activation and proliferation of T-lymphocytes. Although there are several hypotheses regarding the cause of autoimmune diseases and too many findings against and in favor of them, there is still no conclusive data. All these hypothesis and findings are discussed in the context of the more recent advances.