Yu-Chu Wang

By using RNA-immunoprecipitation assay following next-generation sequencing, a group of cell cycle-related genes targeted by hnRNP Q1 were identified, including Aurora-A kinase. Overexpressed hnRNP Q1 can upregulate Aurora-A protein, but not alter the mRNA level, through enhancing the translational efficiency of Aurora-A mRNA, either in a cap-dependent or -independent manner, by interacting with the 5'-UTR of Aurora-A mRNA through its RNA-binding domains (RBDs) 2 and 3. By ribosomal profiling assay further confirmed the translational regulation of Aurora-A mRNA by hnRNP Q1. Overexpression of hnRNP Q1 promotes cell proliferation and tumor growth. HnRNP Q1/ΔRBD23-truncated mutant, which loses the binding ability and translational regulation of Aurora-A mRNA, has no effect on promoting tumor growth. The expression level of hnRNP Q1 is positively correlated with Aurora-A in colorectal cancer. Taken together, our data indicate that hnRNP Q1 is a novel trans-acting factor that binds to Aurora-A mRNA 5'-UTRs and regulates its translation, which increases cell proliferation and contributes to tumorigenesis in colorectal cancer.

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is a morphologically distinctive lesion. Although the clinical course of SANT is benign, its reactive or neoplastic nature remains to be clarified. Furthermore, some investigators have suggested that SANT is related to IgG4 sclerosing lesion or inflammatory pseudotumor with stromal cells positive for Epstein-Barr virus (EBV). In this study, we assessed 22 cases of SANT derived from adult women. Clinical data and follow-up information were obtained by chart review. Immunohistochemical studies for IgG4, IgG, and CD21 stains and in situ hybridization to detect EBV-encoded small RNAs were performed. We also assessed genomic DNA extracted from paraffin-embedded tissue for human androgen-receptor α gene analysis using conventional and methylation-specific polymerase chain reaction methods. The median patient age was 41.5 years (range, 25 to 82 y). Most (77%) patients presented with a single mass that was detected incidentally (59%). The mean size of the lesions was 3.8 cm (range, 1.0 to 9.0 cm). Clinical symptoms correlated with multiple lesions (P=0.043) but not lesional size (P=0.637) or location in the spleen (hilum vs. periphery, P=0.696). None of the cases had evidence of IgG4-related disease or recurred after splenectomy. The mean number of IgG4 cells was 27.7 (range, 4 to 125), and the mean IgG4/IgG ratio was 16.4% (range, 1.6% to 55.7%) with only 2 cases being >40%. Cases with higher IgG4 cells did not correlate with inflammatory pseudotumor-like morphology. No lesions were positive for EBV-encoded small RNAs, and almost all cases with informative results (n=19) showed a polyclonal pattern. We conclude that SANT is a polyclonal, reactive lesion rather than a neoplasm.

Withanolides are generally defined as C(28) steroidal lactones built on an intact or rearranged ergostane skeleton and have been shown to exhibit antiproliferative activity on various types of cancer cells. In this study, we investigated the effect of a new withanolide Tubocapsanolide A isolated from Tubocapsicum anomalum and addressed its molecular action. Tubocapsanolide A inhibited proliferation of A549, H358, and H226 human lung cancer cells via induction of G(1) growth arrest. We found that Tubocapsanolide A treatment led to up-regulation of cyclin E, p21, and p27, whereas other cyclins and cyclin-dependent kinases were not affected in A549 cells. Conversely, Skp2, the F-box protein that is implicated in the mediation of degradation of p21 and p27, was significantly down-regulated. Chromatin immunoprecipitation assay suggested that Tubocapsanolide A suppressed Skp2 expression by inhibiting the binding of Rel A to the nuclear factor-kappaB site of Skp2 gene promoter. In addition, we showed that inhibition of Skp2 is a critical step for the suppression of cell proliferation by Tubocapsanolide A because ectoexpression of Skp2 effectively reversed Tubocapsanolide A-induced p27 up-regulation and growth inhibition in human lung cancer cells. Collectively, we have identified Skp2 as a molecular target for Tubocapsanolide A and suggest that this withanolide may be useful for the prevention or treatment of cancer cells with Skp2 overexpression.