Lípidos nutricionales y hematología en oncología experimental y epidemiológica

Las investigaciones en curso son continuación de trabajos que están en desarrollo, algunas de ellas, desde hace más de 15 años en el laboratorio del Director solicitante, cuyos propósitos son los siguientes: Subtema 1. Determinar en ratones alimentados con dietas con 5 o 20 por ciento de aceites de diversa composición en ácidos grasos poliinsaturados de semillas de a: Zizyphus mistol; b: maíz; c: Oenothera (primavera); d: Oleína; e: Hígado de bacalao, diversos parámetros de crecimiento tumoral de variantes de adenocarcinomas murinos de diversa capacidad metastásica. Subtema 2. Determinar si la suplementación dietaria de todo trans-retinoico per se o combinada con aceites de diversa composición en ácidos grasos, retarda o inhibe el crecimiento de carcinomas murinos de diversa capacidad metastásica. Subtema 3. Determinar si la acción promotora/antipromotora de los lípidos dietarios es debida a la composición particular de ácidos grasos o se relaciona con la población celular que ha sufrido la transformación maligna, iniciada por la irradiación. Subtema 4. 4.1.Determinar si la carencia en ácidos grasos esenciales en combinación con un agente cancerígeno (bena-pyrene) opera como una situación co-promotora del desarrollo tumorigénico en el epitelio malpighiano del esófago-preestómago. 4.2. Establecer si el arsénico per os, en combinación con los lípidos de la dieta opera como un agente co-carcinógeno en esos epitelios malpighianos. Subtema 5. 5.1. Establecer, por medio de estudios de epidemiología Oncológica Nutricional, si hay correlación entre consumo de ciertos nutrientes, especialmente los lípidos, y los hábitos alimentarios con el riesgo de desarrollar cáncer de colon, en la población cordobesa. 5.2. Determinar en áreas de la provincia de Córdoba donde hay hidroarsenicismo crónico regional endémico (HACRE) la correlación entre el riesgo de desarrollar cáncer de esófago, nutrientes, especialmente lípidos, y hábitos alimentarios. Subtema 6. 6.1. Determinar el comportamiento agregatorio de plaquetas sanguíneas isólogas y heterológas frente a células neoplásicas de diferente capacidad metastásica. 6.2. Establecer y caracterizar la capacidad procoagulante de las mencionadas células y también estudiar estos parámetros en células provenientes de cánceres humanos, correlacionándolos con la evolución clínica. Subtema 7. Obtener en forma transplantable en ratones diversos cánceres, caracterizándolos biológica, morfológica y ultraestructuralmente, a fin de constituir un banco de tumores experimentales en nuestro medio.

Expresión de las proteínas relacionadas con la proliferación celular y la apoptosis en lesiones blancas de la mucosa oral, como precursoras de la cancerización en el epitelio escamoso oral.

El cáncer de la mucosa oral es una patología muy frecuente que llega en muchos casos a conformar entre el 8 y el 10% de los tumores malignos del hombre. La baja concientización de la población general sobre el tema es un factor importante que hace que estas lesiones sean detectadas en forma tardía y cuando ya se trata de lesiones avanzadas de muy mal pronóstico. Si bien ha habido grandes avances en el diagnóstico y tratamiento de lesiones blancas de la mucosa oral como el liquen plano oral, estas lesiones siguen siendo entidades con muchos interrogantes para todos los expertos en medicina oral, sobre todo en lo referente a su proceso de aparición y a su tratamiento. Es importante la diferenciación correcta de estas lesiones, ya que el carcinoma epidermoide bucal puede aparecer también como una lesión blanca. No hay suficiente conocimiento de lo que ocurre en otras lesiones blancas de la mucosa oral no liquen plano. Para evaluar el verdadero potencial de transformación maligna de leucoplasias, liquen plano oral, reacciones liquenoides y lesiones escamosas intraepiteliales (incluídas las inducidas por acción viral) se evaluará la expresión de las proteínas relacionadas con la proliferación celular y la apoptosis en estas lesiones. Se evaluará con técnicas inmunohistoquímicas la relación de bcl-2 como marcador apoptótico en leucoplasias, liquen plano oral, lesiones escamosas intraepiteliales y carcinomas epidermoides orales, así como también en estas mismas lesiones la expresión proteica de MIB-1 (ki67), ciclina D1, p16 y p53 para valorar si las alteraciones en la expresión proteica de estos marcadores, suceden de forma secuencial a través de las distintas etapas en la cancerización del campo de cavidad oral, ya que no existe consenso en los resultados y las conclusiones obtenidas en los diferentes estudios efectuados sobre la influencia exclusiva de los marcadores apoptóticos en el desarrollo de las lesiones de algunas de las lesiones como el LPO.

Multiplicações celulares e tumores induzidos por virus: o cancer como infecção

Após terem sido apreciadas, à luz de fatos experimentais, as principais causas determinantes das multiplicações celulares normais e aquelas responsabilidades pelas multiplicações anormais, encontradas nos tumores blastomatosos, foram analisados os tumores animais que reconhecidamente são causados por virus tais como: o sarcoma e o epitelioma das galinhas; o papiloma e o mixoma dos coelhos; os carcinomas de ratos e rãs, e finalmente, o papiloma oral e o linfo-sarcoma venéreo dos cães. Em seguida, foram focalizadas as várias propriedades em comum existentes entre os vírus indutores dêsses tumores como: capacidade de determinar multiplicações anormais nos tecidos atacados; elevada especificidade para as espécies sensíveis; existência de diminuição do poder infeccioso à medida que aumenta a capacidade de estimular a formação de tumores e, as afinidades existentes entre êles e os gens, principalmente àquelas referentes à sensibilidade aos raios X. Finalmente, foi aventada a hipótese da possível existência de elementos patogênicos ainda não identificados, situados entre os virus citocinéticos conhecidos e os gens, com poder infeccioso mínimo, exigindo por isso, condições de susceptibilidade ainda não totalmente conhecidas e controladas, possuidores de elevado poder de induzir multiplicações anormais nos tecidos atacados e possìvelmente responsáveis pelos tumores neoplásicos humanos.

Recent advances in pharmacologic study of natural anticancer agents in China

In this paper a number of anticancer agents of natural origin will be presented. Hydroxycamtothecin (HCPT) was found to produce a strong inhibitory action on a variety of animal tumors. It is also effective for treatment of patients with gastric carcinoma, liver carcinoma, tumor of head and neck or leukemia. Pharmacologic studies showed that it could depress S phase of tumor cells significantly and cause formation of cellular chromatid breaks. By means of alkaline elution and nick translation methods it has been proved that HCPT induced DNA singlo strand breaks remarkably. Homoharringyonine (hhrt) was shown to be effective against acute leukemia. Recent experiments in tumor-bearing mice inidcated that (HHRT) could diminish tumor metastasis. Using molecular hybridization technique it was demonstrated that (HHRT) decreased the content of c-myc RNA in the cytoplasm but not in the nuclei. Lycobetaine (LBT) poddrddrf dytnh inhibitory effects on a number of ascites tumors. In clinical trials it was against ovarian and gastric carcinomas. It is able to intercalate into DNA. Oxalysine (OXL) is a new antibiotic and shown to be effective against tumor metastatis. When used in combination with 5-FU, its anticancer action could be enhanced. Other natural compounds such as indirubin, ß-elemene, irisquinone, oridonine, norcantharidin and PSP have been also found to possess antitumor action.

Involvement of circulating CEA in liver metastases from colorectal cancers re-examined in a new experimental model.

Both experimental and clinical data show evidence of a correlation between elevated blood levels of carcinoembryonic antigen (CEA) and the development of liver metastases from colorectal carcinomas. However, a cause-effect relationship between these two observations has not been demonstrated. For this reason, we developed a new experimental model to evaluate the possible role of circulating CEA in the facilitation of liver metastases. A CEA-negative subclone from the human colon carcinoma cell line CO115 was transfected either with CEA-cDNA truncated at its 3' end by the deletion of 78 base pairs leading to the synthesis of a secreted form of CEA or with a full-length CEA-cDNA leading to the synthesis of the entire CEA molecule linked to the cell surface by a GPI anchor. Transfectants were selected either for their high CEA secretion (clone CO115-2C2 secreting up to 13 microg CEA per 10(6) cells within 72 h) or for their high CEA membrane expression (clone CO115-5F12 expressing up to 1 x 10(6) CEA molecules per cell). When grafted subcutaneously, CO115-2C2 cells gave rise to circulating CEA levels that were directly related to the tumour volume (from 100 to 1000 ng ml(-1) for tumours ranging from 100 to 1000 mm3), whereas no circulating CEA was detectable in CO115 and CO115-5F12 tumour-bearing mice. Three series of nude mice bearing a subcutaneous xenograft from either clone CO115-2C2 or the CO115-5F12 transfectant, or an untransfected CO115 xenograft, were further challenged for induction of experimental liver metastases by intrasplenic injection of three different CEA-expressing human colorectal carcinoma cell lines (LoVo, LS174T or CO112). The number and size of the liver metastases were shown to be independent of the circulating CEA levels induced by the subcutaneous CEA secreting clone (CO115-2C2), but they were directly related to the metastatic properties of the intrasplenically injected tumour cells.

Altered expression of CD44 and DKK1 in the progression of Barrett's esophagus to esophageal adenocarcinoma.

Barrett's esophagus (BE) is an acquired condition in which the normal lining of the esophagus is replaced by intestinal metaplastic epithelium. BE can evolve to esophageal adenocarcinoma (EAC) through low-grade dysplasia (LGD) and high-grade dysplasia (HGD). The only generally accepted marker for increased risk of EAC is the presence of HGD, diagnosed on endoscopic biopsies. More specific markers for the prediction of EAC risk are needed. A tissue microarray was constructed comprising tissue samples from BE, LGD, HGD, and EAC. Marker expression was studied by immunohistochemistry using antibodies against CD44, DKK1, CDX2, COX2, SOX9, OCT1, E-cadherin, and beta-catenin. Immunostaining was evaluated semi-quantitatively. CD44 expression decreased in HGD and EAC relative to BE and LGD. DKK1 expression increased in HGD and EAC relative to BE and LDG. CDX2 expression increased in HGD but decreased in EAC. COX2 expression decreased in EAC, and SOX9 expression increased only in the upper crypt epithelial cells in HGD. E-cadherin expression decreased in EAC. Nuclear beta-catenin was not significantly different between BE, LGD, and HGD. Loss of CD44 and gain of DKK1 expression characterizes progression from BE and LGD to HGD and EAC, and their altered expression might indicate an increased risk for developing an EAC. This observation warrants inclusion of these immunohistochemically detectable markers in a study with a long patient follow-up.

Prevalence of human papillomavirus DNA in female cervical lesions from Rio de Janeiro, Brazil

A hundred-sixty paraffin-embedded specimens from female cervical lesions were examined for human papillomavirus (HPV) types 6, 11, 16 and 18 infections by non-isotopic in situ hybridization. The data were compared with histologic diagnosis. Eighty-eight (55) biopsies contained HPV DNA sequences. In low grade cervical intraepithelial neoplasias (CIN I), HPV infection was detected in 78.7 of the cases, the benign HPV 6 was the most prevalent type. HPV DNA was detected in 58 of CIN II and CIN III cases and in 41.8 of squamous cell carcinomas (SCC). Histologically normal women presented 20 of HPV infection. Oncogenic HPV was found in 10 of these cases, what may indicate a higher risk of developing CINs and cancer. Twenty-five percent of the infected tissues contained mixed infections. HPV 16 was the most common type infecting the cervix and its prevalence raised significantly with the severity of the lesions, pointing its role in cancer pathogenesis. White women presented twice the cervical lesions of mulatto and African origin women, although HPV infection rates were nearly the same for the three groups (approximately 50). Our results showed that HPV typing by in situ hybridization is a useful tool for distinguishing between low and high risk cervical lesions. Further studies are required to elucidate risk factors associated with HPV infection and progression to malignancy in Brazilian population.

TIE-2 and VEGFR Kinase Activities Drive Immunosuppressive Function of TIE-2-Expressing Monocytes in Human Breast Tumors.

PURPOSE: Tumor-associated TIE-2-expressing monocytes (TEM) are highly proangiogenic cells critical for tumor vascularization. We previously showed that, in human breast cancer, TIE-2 and VEGFR pathways control proangiogenic activity of TEMs. Here, we examine the contribution of these pathways to immunosuppressive activity of TEMs. EXPERIMENTAL DESIGN: We investigated the changes in immunosuppressive activity of TEMs and gene expression in response to specific kinase inhibitors of TIE-2 and VEGFR. The ability of tumor TEMs to suppress tumor-specific T-cell response mediated by tumor dendritic cells (DC) was measured in vitro. Characterization of TEM and DC phenotype in addition to their interaction with T cells was done using confocal microscopic images analysis of breast carcinomas. RESULTS: TEMs from breast tumors are able to suppress tumor-specific immune responses. Importantly, proangiogenic and suppressive functions of TEMs are similarly driven by TIE-2 and VEGFR kinase activity. Furthermore, we show that tumor TEMs can function as antigen-presenting cells and elicit a weak proliferation of T cells. Blocking TIE-2 and VEGFR kinase activity induced TEMs to change their phenotype into cells with features of myeloid dendritic cells. We show that immunosuppressive activity of TEMs is associated with high CD86 surface expression and extensive engagement of T regulatory cells in breast tumors. TIE-2 and VEGFR kinase activity was also necessary to maintain high CD86 surface expression levels and to convert T cells into regulatory cells. CONCLUSIONS: These results suggest that TEMs are plastic cells that can be reverted from suppressive, proangiogenic cells into cells that are able to mediate an antitumoral immune response. Clin Cancer Res; 19(13); 3439-49. ©2013 AACR.

Peroxisome proliferator-activated receptor gamma and regulations by the ubiquitin-proteasome system in pancreatic cancer.

Pancreatic cancer is one of the most lethal forms of human cancer. Although progress in oncology has improved outcomes in many forms of cancer, little progress has been made in pancreatic carcinoma and the prognosis of this malignancy remains grim. Several molecular abnormalities often present in pancreatic cancer have been defined and include mutations in K-ras, p53, p16, and DPC4 genes. Nuclear receptor Peroxisome Proliferator-Activated Receptor gamma (PPARγ) has a role in many carcinomas and has been found to be overexpressed in pancreatic cancer. It plays generally a tumor suppressor role antagonizing proteins promoting carcinogenesis such as NF-κB and TGFβ. Regulation of pathways involved in pancreatic carcinogenesis is effectuated by the Ubiquitin Proteasome System (UPS). This paper will examine PPARγ in pancreatic cancer, the regulation of this nuclear receptor by the UPS, and their relationship to other pathways important in pancreatic carcinogenesis.

Der Radioimmunoassay zur Ermittlung des carcinoembryonalen Antigens (CEA), seine Bedeutung und Limitierung während der postoperativen Kontrollperiode von Patienten mit colorectalem Carcino

Carcinoembryonic antigen (CEA) is a tumor marker defined by specific heterologous antisera. Elevated levels of circulating CEA can be detected by radioimmunoassay in most cases of colorectal carcinoma, depending on the degree of tumor spread. The fact that elevation of CEA level can also be observed in other types of carcinomas and in several nonmalignant conditions greatly limits the value of the CEA test for the early diagnosis of colorectal carcinomas. Repeated CEA measurements and their critical interpretation, however, appear to be of importance after tumor resection for the detection of tumor recurrence during the postoperative follow-up period.

Activin enhances skin tumourigenesis and malignant progression by inducing a pro-tumourigenic immune cell response.

Activin is an important orchestrator of wound repair, but its potential role in skin carcinogenesis has not been addressed. Here we show using different types of genetically modified mice that enhanced levels of activin in the skin promote skin tumour formation and their malignant progression through induction of a pro-tumourigenic microenvironment. This includes accumulation of tumour-promoting Langerhans cells and regulatory T cells in the epidermis. Furthermore, activin inhibits proliferation of tumour-suppressive epidermal γδ T cells, resulting in their progressive loss during tumour promotion. An increase in activin expression was also found in human cutaneous basal and squamous cell carcinomas when compared with control tissue. These findings highlight the parallels between wound healing and cancer, and suggest inhibition of activin action as a promising strategy for the treatment of cancers overexpressing this factor.

EGFR signalling as a negative regulator of Notch1 gene transcription and function in proliferating keratinocytes and cancer.

The Notch1 gene has an important role in mammalian cell-fate decision and tumorigenesis. Upstream control mechanisms for transcription of this gene are still poorly understood. In a chemical genetics screen for small molecule activators of Notch signalling, we identified epidermal growth factor receptor (EGFR) as a key negative regulator of Notch1 gene expression in primary human keratinocytes, intact epidermis and skin squamous cell carcinomas (SCCs). The underlying mechanism for negative control of the Notch1 gene in human cells, as well as in a mouse model of EGFR-dependent skin carcinogenesis, involves transcriptional suppression of p53 by the EGFR effector c-Jun. Suppression of Notch signalling in cancer cells counteracts the differentiation-inducing effects of EGFR inhibitors while, at the same time, synergizing with these compounds in induction of apoptosis. Thus, our data reveal a key role of EGFR signalling in the negative regulation of Notch1 gene transcription, of potential relevance for combinatory approaches for cancer therapy.

Importancia de los factores predictivos patológicos vigentes en el carcinoma de células renales cromófobo

Introducció: Els factors predictius patològics vigents per al carcinoma de cèl•lules renals cromòfob (CCRC) mantenen gran controvèrsia en la actualitat, sent la utilitat de la classificació del grau nuclear Fuhrman per a aquest subtipus histològic un dels factors més qüestionats. Objectiu: Avaluar la utilitat pronòstica dels actuals factors patològics predictius a la nostra sèrie de carcinomes de cèl•lules renals tipus cromòfob. Materials i metodologia: Realitzarem una revisió retrospectiva dels paràmetres clínico-patològics de pacients portats a nefrectomia radical per CCRC. Les característiques clínico-patològiques analitzades van ser l’estadi TNM, grau Fuhrman, invasió microvascular, necrosi tumoral, trombus tumoral, marges quirúrgics positius, invasió del greix perinefrític i compromís del sistema col•lector. Resultats: En l’anàlisi multivariant només l’estadi tumoral es va confirmar com a factor predictiu independent de recurrència. Conclusions: l’estadi tumoral prediu agressivitat en el CCR cromòfob. La classificació de grau nuclear de Fuhrman no és útil en aquest subtipus histològic.

Virus Papiloma Humano en el carcinoma escamoso de cabeza y cuello

Els carcinomes de cèl•lules escamoses de cap i coll (CCECC) estan relacionats en un 80% dels casos amb el tabac i/o l’alcohol. Per altra banda, la infecció per virus papil•loma humà (VPH), la malaltia de transmissió sexual més freqüent als Estats Units actualment, ha resultat ser oncogènica no només a nivell genital sinó també a nivell del tracte aero-digestiu superior, sobretot a oro-faringe. Els estudis realitzats a posteriori han demostrat que els pacients amb CCECC VPH+ no fumadors ni bebedors, solen ser més joves, presentar diferents marcadors tumorals, respondre més al tractament i tenir millor pronòstic.

Cutaneous cancer stem cell maintenance is dependent on beta-catenin signalling.

Continuous turnover of epithelia is ensured by the extensive self-renewal capacity of tissue-specific stem cells. Similarly, epithelial tumour maintenance relies on cancer stem cells (CSCs), which co-opt stem cell properties. For most tumours, the cellular origin of these CSCs and regulatory pathways essential for sustaining stemness have not been identified. In murine skin, follicular morphogenesis is driven by bulge stem cells that specifically express CD34. Here we identify a population of cells in early epidermal tumours characterized by phenotypic and functional similarities to normal bulge skin stem cells. This population contains CSCs, which are the only cells with tumour initiation properties. Transplants derived from these CSCs preserve the hierarchical organization of the primary tumour. We describe beta-catenin signalling as being essential in sustaining the CSC phenotype. Ablation of the beta-catenin gene results in the loss of CSCs and complete tumour regression. In addition, we provide evidence for the involvement of increased beta-catenin signalling in malignant human squamous cell carcinomas. Because Wnt/beta-catenin signalling is not essential for normal epidermal homeostasis, such a mechanistic difference may thus be targeted to eliminate CSCs and consequently eradicate squamous cell carcinomas.