Human mesothelioma cells exhibit tumor cell-specific differences in phosphatidylinositol 3-kinase/AKT activity that predict the efficacy of Onconase

Malignant mesothelioma is an aggressive cancer with no known cure, which has become a therapeutic challenge. Onconase is one of few chemotherapeutic agents that have been studied in patients with malignant mesothelioma that has the advantage of low toxicity and limited side effects. Here, we evaluate the effect of Onconase on killing of malignant mesothelioma cells and how the phosphatidylinositol 3-kinase/AKT (PI3-K/AKT) survival pathway influences this effect. Our results show that Onconase induces apoptosis in malignant mesothelioma cell lines and that this effect is tumor cell specific. Malignant mesothelioma cell lines with the highest AKT activation, which correlated with the presence of the SV40 large and small T antigen (SV40+), were the most resistant to the drug. Finally, a cooperative effect was observed between small molecule inhibitors of PI3-K and Onconase in the killing of malignant mesothelioma cells. Our results suggest that kinase screening of individual malignant mesotheliomas for endogenous levels of activated PI3-K/AKT may be predictive of the efficacy of Onconase and possibly other chemotherapeutic agents.     

Placental stress factors and maternal-fetal adaptive response: the corticotropin-releasing factor family

The placenta and its accessory membranes amnion and chorion undertake the role of intermediary barriers and active messengers in the maternal-fetal dialog. They synthesize, metabolize, and serve as target to numerous hormones that regulate maternal and fetal physiology during pregnancy. Among these factors, corticotropin-releasing factor (CRF) has been one of the more investigated in the last decade. Increasing evidence indicates that in the event of acute or chronic metabolic, physical, or infectious stress, maternal or fetal physiologic and pathologic conditions may influence placental secretion of CRF. The current opinion is that the placenta actually takes part in a stress syndrome by releasing CRF, which may help to influence uterine perfusion, maternal metabolism, fluid balance, and possibly uterine contractility, thereby protecting the fetus from a hostile environment.     

Simian virus-40 sequences are a negative prognostic cofactor in patients with malignant pleural mesothelioma

Several biochemical and clinical factors have been shown to correlate with survival in human malignant pleural mesothelioma (MM). Nevertheless, average survival of 4 to 10 months from diagnosis is sometimes not sufficient for full expression of these factors. Several studies have reported SV40 sequences in MM, suggesting a possible pathogenic role. We investigated whether the presence of these sequences had any effect on MM patient survival. For this study, we used polymerase chain reaction and Southern blot analysis to search for and identify SV40 DNA in biopsy samples from 83 MM patients. These cases were divided according to histology: 62/83 (74. 7%) had epithelioid morphology (EMM) and 21/83 (25.3%) had either biphasic or sarcomatous morphology (B/SMM). SV40 positivity was significantly associated with B/SMM growth pattern (chi-squared test = 5.03, P = 0.025). Kaplan-Meier univariate analysis confirmed the independent effect of histology on MM survival (log-rank test = 13.9, P < 0.001) and showed a trend for increased survival in SV40-negative patients (log-rank test = 2.83, P = 0.09). Most importantly, Cox's regression model showed that SV40-positive status affected the predictive value of histology on patient survival. In particular, when SV40 expression was added to the B/SMM histotype, Cox's regression model showed a significant increase in hazard ratio (HR) with respect to SV40-negative B/SMM (HR = 4.25, 95% CI = 2.00-9. 00, likelihood ratio test = 14.31, P < 0.001). We conclude that SV40 expression is significantly associated with B/SMM histology and represents an important prognostic cofactor when associated with the tumor subtype in MM patients.     

Expression of glycoprotein 90K in human malignant pleural mesothelioma: correlation with patient survival

The expression of the tumour-associated glycoprotein 90K in patients with malignant pleural mesothelioma (MM) has not been described. This study used enzyme-linked immunoassay (ELISA) to measure 90K in pleural effusions (PEs) and sera from patients with MM (n=28), lung cancer (LC) (n=14) and benign pleural disease (BPD) (n=15). Immunohistochemistry was used to investigate 90K expression in MM and LC tissue sections. The expression of 90K was further evaluated in vitro by ELISA and western blot analysis of conditioned media and cellular extracts of MM, LC and normal human mesothelial (NHM) cell cultures. Finally, the relationships between 90K expression in MM and patient age and survival were studied. The mean 90K level was significantly higher (p<0.05) in PEs of MM patients (11.0+/-6.6 microg/ml) than in LC (6.1+/-3.2 microg/ml) or BPD (6.2+/-5.0 microg/ml) patients. Immunohistochemistry showed a positive reaction for 90K in MM biopsy sections and positive staining limited to inflammatory infiltrates in LC sections. The level of 90K was significantly higher in cell culture media of MM than of LC or NHM (p<0.001). Bands representing proteins with molecular weight of approximately 90 kDa were detected by western blot in MM cellular extracts. An inverse correlation between PE 90K levels and MM patient age (r=-0.45; p=0.017) and a positive correlation between serum 90K levels and MM patient survival (r=0.62; p=0.006) were detected by linear regression analysis. Kaplan-Meier univariate analysis showed increased survival probability for MM patients with serum 90K level >7.3 microg/ml (log rank, p<0.05). This is the first report in MM of the expression of 90K and of its potential diagnostic and prognostic application.     

Modulation of integrin expression on mesotheliomas: the role of different histotypes in invasiveness.

The in vitro and in vivo integrin expression in human pleural malignant mesothelioma (MM) of three different histotypes was studied. Cell lines from MM of epithelioid (E1), fibrous (F1), byphasic histotype (B1) and normal mesothelial cells (NM) were analysed for the surface expression of alpha2, alpha3, alpha4, alpha5, alpha6, alphav, beta1, beta3, beta4 subunits and alphavbeta5 integrins. We found that alpha6, beta4 subunits and alphavbeta5, weakly detectable on NM cells, were expressed on MM cells. The beta3 subunit, well expressed on NM cells, was absent on MM cells. Differential expression among histotypes was observed, the MM-E1 was the least and the MM-B1 the most positive. Specimens for each MM histotype, were analysed by immunohistochemistry. The alpha6 and alphav subunits were more evident on the epithelioid histotype. Intense staining for beta3 and beta4 subunits, was found in all MM, particularly in invading cells, while the alpha5, and alphavbeta5 integrins were variously expressed. The different histotypes can affect the in vitro integrin expression and may indicate a preferential involvement of some subunits in vivo during MM tumor progression.     

Natural human polyreactive IgM induce apoptosis of lymphoid cell lines and human peripheral blood mononuclear cells

Natural polyreactive IgM autoantibodies, encoded by unmutated germline Ig V genes, represent a major fraction of the normal circulating IgM repertoire. We have previously shown that therapeutic preparation of pooled IgM exerts immunomodulatory effects as assessed by in vitro and in vivo studies. Here, we show that the IgM preparation induces cell death in lymphoblastoid cell lines and in human peripheral blood mononuclear cells. The IgM-induced cell death involved classical features of apoptosis such as nuclear fragmentation and activation of caspases. Treatment of leukemic cells with IgM resulted in the cleavage of poly-(A)DP ribose polymerase, a substrate of caspase, and in a reduction in mitochondrial transmembrane potential during the early period of apoptosis induction. Natural IgM-induced apoptosis was inhibited by soluble Fas molecules and affinity-purified Fas antibodies from pooled IgM preparation induced apoptosis in lymphoblastoid cells, suggesting the involvement of the Fas receptor. Our results suggest a role for normal IgM in controlling cell death and proliferation, and imply a possible therapeutic role for IgM in autoimmune and lymphoproliferative disorders.     

Cancer testis antigens expression in mesothelioma: role of DNA methylation and bioimmunotherapeutic implications

Recent evidences suggest that malignant mesothelioma may be sensitive to immunotherapy; however, little is known about malignant mesothelioma-associated tumour antigens. Focusing on cancer/testis antigens, the expression of well-characterised immunogenic tumour-associated antigens was investigated in malignant mesothelioma cells. At variance with MAGE-4 and NY-ESO-1, malignant mesothelioma cells frequently expressed MAGE-1, -2 and -3, GAGE 1-2, GAGE 1-6, SSX-2 and SSX 1-5, and distinct malignant mesothelioma cells concomitantly expressed at least four cancer/testis antigens. Additionally, the tumour-associated antigens RAGE-1 was expressed at high levels in both benign and malignant mesothelial cells. Lastly, treatment with the DNA hypomethylating agent 5-aza-2'-deoxycytidine induced and up-regulated the expression of the cancer/testis antigen examined in malignant mesothelioma cells. Overall, these findings strongly suggest that cancer/testis antigens-based immunotherapy may represent a suitable therapeutic approach to malignant mesothelioma, and foresee the clinical use of 5-aza-2'-deoxycytidine to design new chemo-immunotherapeutic strategies in malignant mesothelioma patients.     

Vitiligo associated with other autoimmune diseases: polyglandular autoimmune syndrome types 3B+C and 4

Vitiligo is a common skin disease characterized by depigmented maculae resulting from a reduction of the number and function of melanocytes. Many studies suggest that vitiligo might be an autoimmune disease. Vitiligo has been frequently described in association with other autoimmune diseases. Among the diseases described in association with vitiligo are the so-called autoimmune polyglandular syndromes (APS). Vitiligo can be present in all types of APS but the most frequent association appears to be in APS-3. APS-3 was defined as the association between autoimmune thyroiditis and another autoimmune disease. Here we report one patient with thyroiditis, vitiligo and autoimmune gastritis (APS-3B+C), one patient with chronic autoimmune thyroiditis, vitiligo and alopecia (APS-3C), and one case of a young patient with type 1 diabetes mellitus and vitiligo (APS-4), according to the newest classification. We stress the importance of a thorough assessment for autoimmune diseases in selected patients with vitiligo.