Upregulation of NKG2D ligands and enhanced natural killer cell cytotoxicity by hydralazine and valproate.

Natural killer cells play a role in the immune antitumor response by recognizing and eliminating tumor cells through the engagement of NKG2D receptors with their ligands on target cells. This work aimed to investigate whether epigenetic drugs are able to increase MICA and MICB expression as well as NK cell cytotoxicity. Prostate, colon, breast and cervical cancer cell lines were analyzed for the expression of MICA and MICB at the mRNA and protein levels by RT-PCR, Western blot, flow cytometry and ELISA. The activating mark H3K4m2 at the MICA and MICB promoters was investigated by ChIP assays. Cytotoxicity of NK cells against the target epithelial cancer cells was investigated with the CD107 cytotoxicity assay. The results show that hydralazine and valproic acid not only increase the expression of MICA and MICB ligands of target cells, but also reduce their shedding to the supernatant. This upregulation occurs at the transcriptional level as revealed by increase of the H3K4 activating mark at the promoter of MICA and MICB genes. These effects are paralleled by increased cytotoxicity of NK cells, which was attenuated at different degrees by using blocking antibodies against the NKG2D receptor and ligands. In conclusion, our results demonstrate the ability of hydralazine and valproate to increase the NK activity against epithelial cancer cell lines and suggest that these drugs could reduce the levels of soluble MICA and MICB helping in avoiding tumor-induced suppression of NK cytotoxicity against the tumor.

Thrombin is present in the lungs of patients with primary extremity osteosarcoma and pulmonary metastases.

Osteosarcoma is a rare cancer, which metastasizes to the lung in up to 80% of cases. Thrombin is involved in metastasis and is present in the lungs of patients with pulmonary metastases (PM). To identify its role in PM and osteosarcoma, we measured thrombin levels in the bronchoalveolar lavage fluid (BALF) of 15 patients. BALF was collected at different stages of the disease and correlated with the diagnosis of PM. We also assessed fibrinogen overexpression in the tumors. We found that 11/15 (73%) patients with high thrombin levels in the lungs developed PM within the first 12 months from primary surgery. The median thrombin concentration in the BALF of these patients increased up to 8x10(-9) M (range, 3x10(-9)M-15x10(-9)M), which represents a more than 100-fold increase compared to patients without PM (p<0.0001). Eight of 15 (53%) primary and 11/15 (73%) metastatic samples showed fibrinogen overexpression. A significant difference between high thrombin levels, fibrinogen overexpression and PM was found compared to patients without PM (p=0.00073 and p=0.025). These results show that thrombin levels are increased in the lungs of patients with primary osteosarcoma and a high risk of developing PM. They suggest that thrombin may be involved in the development of PM.

Ki-67: a proliferative marker that may predict pulmonary metastases and mortality of primary osteosarcoma.

Alterations in Ki-67 activity have been associated with tumor progression and poor outcome in cancer patients. This study was undertaken to identify the potential of this proliferative marker as a predictor of pulmonary metastases (PM) and mortality in osteosarcoma patients. In 38 patients with tissue available for immunohistochemical analysis, overexpression of Ki-67 was assessed. Chi-square and log rank tests were used to determine differences between proportions of the marker with PM and mortality and survival distributions respectively. P values equal or less than .05 were considered statistically significant. The median follow up of this case series was 28 months. Eighteen (47.4%) of 38 patients developed PM, and 17 (44%) overexpressed Ki-67. We found a high frequency of PM (15 of 17) among those cases that overexpressed Ki-67. This relationship was significant (P = .000006) when compared to the rest of the group. We also found a statistically significant correlation between patients with positive and negative Ki-67 scores and higher and lower mortality (P = .000962). These findings suggest that Ki-67 overexpression could be used as a prognostic molecular marker for the development of PM in osteosarcoma patients.

Evidence that thrombin present in lungs of patients with pulmonary metastasis may contribute to the development of the disease.

Early cellular events in the lung which may lead to the development of pulmonary metastases (PM) are still poorly understood. Thrombin, a key component of the coagulation cascade, may be involved in the development of PM as it has been shown to be an enhancer of platelet-tumor interaction in vitro and metastasis in vivo, and because it has been found in high levels in lungs from patients with PM. In this study, we assessed the potential role of thrombin in promoting PM by inducing an enhancement of tumor cell adhesion to platelets and tumor cell chemoinvasion and proliferation. We used bronchoalveolar lavage fluid (BALF) from 20 patients with PM. Results were compared with those from healthy controls. We found an enhancement of adhesion of PM-BALF-treated tumor cells to untreated platelets. BALF from patients with PM significantly increased chemoinvasion and proliferation in three human tumor cell lines. These activities were attenuated significantly by a thrombin inhibitor: hirudin. These results indicate that the thrombin present in the lungs of patients with PM is, at least in part, responsible for their adhesive, invasive and mitogenic activity on three different tumor cell lines. They also suggest that thrombin may be involved in the development of PM.

Frecuencia y distribución de metástasis pulmonar por sarcoma óseo en el Instituto Nacional de Cancerología: periodo 1986-1996 / Frequency and distribution of pulmonary metastases induced by bone sarcoma in the Instituto Nacional de Cancerologia: period 1986-1996

Antecedentes. Los sarcomas óseos son poco frecuentes, pero inducen hasta 80 por ciento de metástasis pulmonar. En población mexicana esta información se desconoce, por lo que describimos su frecuencia en el Instituto Nacional de Cancerología. Métodos. Se revisaron los expedientes de pacientes con sarcoma, registrados entre 1986-1996. Se recabo información demográfica, la histología del tumor y el tiempo de desarrollo de la metástasis. Resultados. Se incluyeron en el estudio 173 casos. De éstos, 74 (43 por ciento) desarrollaron metástasis pulmonar; 102 (60 por ciento) fueron hombres y 71 (40 por ciento) mujeres. Se observó una mediana de edad de 21 años. Se registraron 120 (70 por ciento) casos con diagnóstico de osteosarcoma, 54 (45 por ciento) de los cuales presentaron metástasis; 35 (20 por ciento) casos de condrosarcoma, en 10 (29 por ciento) de los cuales se confirmó metástasis a pulmón y 18 (10 por ciento) casos con sarcoma de Ewing, 10 (56 por ciento) de éstos con metástasis. Considerando la fecha de ingreso, se observaron medianas de tiempo de desarrollo de metástasis pulmonar de hasta 15 meses. A 50 meses, en los pacientes con sarcoma de Ewing, se calculó una supervivencia del 60 por ciento, significativamente menor a la observada en los otros grupos (p=0.0368). Los pacientes con osteosarcoma y metástasis presentaron una supervivencia del 70 por ciento a 50 meses, significativamente menor a la registrada de los osteosarcomas sin metástasis (p=0.0319). Conclusiones. Se encontró una frecuencia del 43 por ciento de metástasis pulmonar. El osteosarcoma y el sarcoma de Ewing fueron los principales inductores de este tipo de metástasis y los grupos en los que se registraron los menores tiempos de supervivencia en presencia o no de metástasis, respectivamente