MicroRNA-150 is a potential biomarker of HIV/AIDS disease progression and therapy.

BACKGROUND: The surrogate markers of HIV/AIDS progression include CD4 T cell count and plasma viral load. But, their reliability has been questioned in patients on anti-retroviral therapy (ART). Five microRNAs (miRNAs) - miR-16, miR-146b-5p, miR-150, miR-191 and miR-223 in peripheral blood mononuclear cells (PBMCs) were earlier found to assign HIV/AIDS patients into groups with varying CD4 T cell counts and viral loads. In this pilot study, we profiled the expression of these five miRNAs in PBMCs, and two of these miRNAs (miR-146b-5p and miR-150) in the plasma of HIV/AIDS patients, including those on ART and those who developed ART resistance, to evaluate if these are biomarkers of disease progression and therapy. RESULTS: We quantified miRNA levels by quantitative reverse transcription polymerase chain reaction (qRT-PCR) using RNA isolated from PBMCs and plasma of healthy persons or HIV-infected patients who were (1) asymptomatic; (2) symptomatic and ART naïve; (3) on ART; and (4) failing ART. Our results show miR-150 (p<0.01) and to a lesser extent miR-146b-5p (p<0.05) levels in PBMCs to reliably distinguish between ART-naïve AIDS patients, those on ART, and those developing drug resistance and failing ART. The plasma levels of these two miRNAs also varied significantly between patients in these groups and between patients and healthy controls (p values <0.05). CONCLUSIONS: We report for the first time that PBMC and plasma levels of miR-150 and miR-146b-5p are predictive of HIV/AIDS disease progression and therapy

NSC666715 and Its Analogs Inhibit Strand-Displacement Activity of DNA Polymerase β and Potentiate Temozolomide-Induced DNA Damage, Senescence and Apoptosis in Colorectal Cancer Cells.

Recently approved chemotherapeutic agents to treat colorectal cancer (CRC) have made some impact; however, there is an urgent need for newer targeted agents and strategies to circumvent CRC growth and metastasis. CRC frequently exhibits natural resistance to chemotherapy and those who do respond initially later acquire drug resistance. A mechanism to potentially sensitize CRC cells is by blocking the DNA polymerase β (Pol-β) activity. Temozolomide (TMZ), an alkylating agent, and other DNA-interacting agents exert DNA damage primarily repaired by a Pol-β-directed base excision repair (BER) pathway. In previous studies, we used structure-based molecular docking of Pol-β and identified a potent small molecule inhibitor (NSC666715). In the present study, we have determined the mechanism by which NSC666715 and its analogs block Fen1-induced strand-displacement activity of Pol-β-directed LP-BER, cause apurinic/apyrimidinic (AP) site accumulation and induce S-phase cell cycle arrest. Induction of S-phase cell cycle arrest leads to senescence and apoptosis of CRC cells through the p53/p21 pathway. Our initial findings also show a 10-fold reduction of the IC50 of TMZ when combined with NSC666715. These results provide a guide for the development of a target-defined strategy for CRC chemotherapy that will be based on the mechanisms of action of NSC666715 and TMZ. This combination strategy can be used as a framework to further reduce the TMZ dosages and resistance in CRC patients

Adenomatous Polyposis Coli-Mediated Accumulation of Abasic DNA Lesions Lead to Cigarette Smoke Condensate-Induced Neoplastic Transformation of Normal Breast Epithelial Cells

Adenomatous polyposis coli (APC) is a multifunctional protein having diverse cellular functions including cell migration, cell-cell adhesion, cell cycle control, chromosomal segregation, and apoptosis. Recently, we found a new role of APC in base excision repair (BER) and showed that it interacts with DNA polymerase β and 5′-flap endonuclease 1 and interferes in BER. Previously, we have also reported that cigarette smoke condensate (CSC) increases expression of APC and enhances the growth of normal human breast epithelial (MCF10A) cells in vitro. In the present study, using APC overexpression and knockdown systems, we have examined the molecular mechanisms by which CSC and its major component, Benzo[α]pyrene, enhances APC-mediated accumulation of abasic DNA lesions, which is cytotoxic and mutagenic in nature, leading to enhanced neoplastic transformation of MCF10A cells in an orthotopic xenograft model

PBMC miRNAs as classifiers for different sets of patients.

<p>Receiver operating characteristic (ROC) curve analysis is shown for the expression ratio of (a) miR-150/RNU44 as classifier of CD4+ T-cell counts, (b) miR-146b-5p/RNU44 as classifier of CD4+ T-cell counts, and (c) miR-16/RNU44 as a classifier of viral load. Comparisons are made between Set-A (healthy, HIV+ asymptomatic and patients on ART) versus Set-B (HIV+ symptomatic and ART resistance patients), as described in the text.</p

Relative plasma levels of miRNAs.

<p>The expression levels (mean ± SEM) of plasma miR-150 (a, b) and miR-146b-5p (c, d) normalized to miR-16 (a, c) and cel-miR-39 (b, d) in different groups of HIV patients and healthy controls are shown. The asterisks denote statistically significant differences (** p<0.01, * p<0.05) for the indicated groups (Student's T test).</p

miRNAs as classifiers for patients without and with ART.

<p>Receiver operating characteristic (ROC) curve analysis of expression ratio of (a) PBMC miR-150/RNU-44, (b) plasma miR-150/miR-16, (c) PBMC miR-146b-5p/RNU-44 and (d) plasma miR-146b-5p/miR-16, as classifier of Set-C (HIV+; asymptomatic and symptomatic) versus Set-D (patients on ART) shown on left panels; and Set-D versus Set-E (ART resistance patients) shown on right panels. Insets of plots show area under curve (AUC), standard error (SE) and significance (p value).</p

Correlation of miRNA levels with CD4 counts and viral load.

<p>The correlations are shown for (a) miR-150 in PBMCs with absolute CD4+ T-cell counts and (b) miR-146b-5p in PBMCs with HIV viral loads. A positive significant correlation was noted between miR-150 and CD4 cell count (r = 0.64; p<0.01) and an inverse correlation between miR-146b-5p and HIV viral loads (r = −0.34; p<0.05).</p