Molecular Mechanism for Protection Against Liver Failure in Human Yellow Fever Infection.

Yellow fever (YF) is a viral hemorrhagic fever that typically involves the liver. Brazil recently experienced its largest recorded YF outbreak, and the disease was fatal in more than a third of affected individuals, mostly because of acute liver failure. Affected individuals are generally treated only supportively, but during the recent Brazilian outbreak, selected patients were treated with liver transplant. We took advantage of this clinical experience to better characterize the clinical and pathological features of YF-induced liver failure and to examine the mechanism of hepatocellular injury in YF, to identify targets that would be amenable to therapeutic intervention in preventing progression to liver failure and death. Patients with YF liver failure rapidly developed massive transaminase elevations, with jaundice, coagulopathy, thrombocytopenia, and usually hepatic encephalopathy, along with pathological findings that included microvesicular steatosis and lytic necrosis. Hepatocytes began to express the type 3 isoform of the inositol trisphosphate receptor (ITPR3), an intracellular calcium (Ca2+) channel that is not normally expressed in hepatocytes. Experiments in an animal model, isolated hepatocytes, and liver-derived cell lines showed that this new expression of ITPR3 was associated with increased nuclear Ca2+ signaling and hepatocyte proliferation, and reduced steatosis and cell death induced by the YF virus. Conclusion: Yellow fever often induces liver failure characterized by massive hepatocellular damage plus steatosis. New expression of ITPR3 also occurs in YF-infected hepatocytes, which may represent an endogenous protective mechanism that could suggest approaches to treat affected individuals before they progress to liver failure, thereby decreasing the mortality of this disease in a way that does not rely on the costly and limited resource of liver transplantation.

CAISMOV24, a new human low-grade serous ovarian carcinoma cell line.

BACKGROUND: The spontaneous immortalization of primary malignant cells is frequently assigned to their genetic instability during in vitro culturing. In this study, the new epithelial ovarian cancer cell line CAISMOV24 was described and compared with its original low-grade serous ovarian carcinoma. METHODS: The in vitro culture was established with cells isolated from ascites of a 60-year-old female patient with recurrent ovarian cancer. The CAISMOV24 line was assessed for cell growth, production of soluble biomarkers, expression of surface molecules and screened for typical mutations found in serous ovarian carcinoma. Additionally, comparative genomic hybridization was employed to compare genomic alterations between the CAISMOV24 cell line and its primary malignant cells. RESULTS: CAISMOV24 has been in continuous culture for more than 30 months and more than 100 in vitro passages. The cell surface molecules EpCAM, PVR and CD73 are overexpressed on CAISMOV24 cells compared to the primary malignant cells. CAISMOV24 continues to produce CA125 and HE4 in vitro. Although the cell line had developed alongside the accumulation of genomic alterations (28 CNV in primary cells and 37 CNV in CAISMOV24), most of them were related to CNVs already present in primary malignant cells. CAISMOV24 cell line harbored KRAS mutation with wild type TP53, therefore it is characterized as low-grade serous carcinoma. CONCLUSION: Our results corroborate with the idea that genomic alterations, depicted by CNVs, can be used for subtyping epithelial ovarian carcinomas. Additionally, CAISMOV24 cell line was characterized as a low-grade serous ovarian carcinoma, which still resembles its primary malignant cells.

PI3K inhibition synergizes with glucocorticoids but antagonizes with methotrexate in T-cell acute lymphoblastic leukemia.

The PI3K pathway is frequently hyperactivated in primary T-cell acute lymphoblastic leukemia (T-ALL) cells. Activation of the PI3K pathway has been suggested as one mechanism of glucocorticoid resistance in T-ALL, and patients harboring mutations in the PI3K negative regulator PTEN may be at increased risk of induction failure and relapse. By gene expression microarray analysis of T-ALL cells treated with the PI3K inhibitor AS605240, we identified Myc as a prominent downstream target of the PI3K pathway. A significant association was found between the AS605240 gene expression signature and that of glucocorticoid resistance and relapse in T-ALL. AS605240 showed anti-leukemic activity and strong synergism with glucocorticoids both in vitro and in a NOD/SCID xenograft model of T-ALL. In contrast, PI3K inhibition showed antagonism with methotrexate and daunorubicin, drugs that preferentially target dividing cells. This antagonistic interaction, however, could be circumvented by the use of correct drug scheduling schemes. Our data indicate the potential benefits and difficulties for the incorporation of PI3K inhibitors in T-ALL therapy.

Recombinant envelope protein-based enzyme immunoassay for IgG antibodies is comparable to neutralization tests for epidemiological studies of dengue infection.

Dengue virus (DENV) is the most prevalent arbovirus in the world, found mainly in tropical regions. As clinical manifestations present frequently as nonspecific febrile illness, laboratory diagnosis is essential to confirm DENV infections and for epidemiological studies. Recombinant envelope (E) antigens of four serotypes of DENV were used to develop an immunoglobulin G enzyme-linked immunosorbent assay (IgG-ELISA). To evaluate the IgG-ELISA, a panel of serum samples that had been tested previously by a plaque reduction neutralization test (PRNT) was investigated for the presence of anti-E antibodies against the four DENV serotypes. IgG-ELISA was found to have a sensitivity (91%) and specificity (98%) at a receiver-operating characteristic (ROC) optimized cutoff and demonstrated high performance as well as good indexes. A concordance of 97% was achieved between both assays, and only 21/704 (3%) samples were not concordant. The results of the present study demonstrate a moderate correlation between neutralizing antibody titers and IgG-ELISA values. These findings indicate that the recombinant protein-based IgG-ELISA is a suitable method for routine serodiagnosis, monitoring and seroepidemiological studies of DENV infections.