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Datar I.,University of Toledo | Feng J.,University of Toledo | Qiu X.,University of Toledo | Lewandowski J.,University of Toledo | And 11 more authors.
PLoS ONE | Year: 2015

Raf Kinase Inhibitory Protein or RKIP was initially identified as a Raf-1 binding protein using the yeast 2-hybrid screen. RKIP inhibits the activation phosphorylation ofMEK by Raf-1 by competitively inhibiting the binding of MEK to Raf-1 and thus exerting an inhibitory effect on the Raf-MEK-Erk pathway. RKIP has been identified as a metastasis suppressor gene. Expression of RKIP is low in cancermetastases. Although primary tumor growth remains unaffected, re- expression of RKIP inhibits cancer metastasis. Mechanistically, RKIP constrainsmetastasis by inhibiting angiogenesis, local invasion, intravasation, and colonization. Themolecular mechanism of how RKIP inhibits these individual steps remains undefined. In our present study, using an unbiased PCR based screening and by analyzing DNA microarray expression datasets we observe that the expression of multiple metaloproteases (MMPs) including MMP1, MMP3, MMP10 and MMP13 are negatively correlated with RKIP expression in breast cancer cell lines and clinical samples. Since expression of MMPs by cancer cells is important for cancer metastasis, we hypothesize that RKIP may mediate suppression of breast cancer metastasis by inhibiting multiple MMPs. We show that the expression signature of RKIP and MMPs is better at predicting highmetastatic risk than the individual gene. Using a combination of loss- and gain-of-function approaches, we find that MMP13 is the cause of RKIP-mediated inhibition of local cancer invasion. Interestingly expression ofMMP13 alone is not sufficient to reverse the inhibition of breast cancer cellmetastasis to the lung due to the expression of RKIP. We find that RKIP negatively regulatesMMP13 through the Erk2 signaling pathway and the repression of MMP13 by RKIP is transcription factor AP-1 independent. Together, our findings indicate that RKIP inhibits cancer cell invasion, in part, via MMP13 inhibition. These data also implicate RKIP in the regulation of MMP transcription, suggesting a potential mechanism by which RKIP inhibits tumor progression and metastasis. © 2015 Correia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source


Chai C.,Southwest University | Zhang Y.,Southwest University | Sun W.,Southwest University | Ding G.,Southwest University | And 5 more authors.
Gene | Year: 2014

In this report, we examined the gene expression related to carotenoid transport for a silkworm F1 hybrid with yellow cocoon generated by crossing two white-cocoon strains, Qiubai and 12-260. Our results showed that, in Qiubai, Cameo2, a transmembrane protein gene belonging to the CD36 family genes, was expressed normally in the silk gland, but no intact carotenoid-binding protein (CBP) mRNA (only the truncated CBP mRNA) was detected in the midgut. In 12-260, we detected the intact CBP mRNA expression in the midgut, but no Cameo2 expression in the silk gland. Regarding the F1 hybrid from crossing Qiubai and 12-260, both Cameo2 and intact CBP mRNA expressed normally in the silk gland and midgut. HPLC detection confirmed that in the F1 hybrid the carotenoids could be absorbed from dietary mulberry leaves through the midgut and transferred to silk gland via the hemolymph, which eventually colored cocoons into yellow. We also identified four CBP mRNA isoforms expressed in the midgut of the F1 hybrid, subsequently named as variants 5-8. Our results provide further evidences for the roles of Cameo2 and CBP in the formation of yellow cocoon of silkworm. © 2013 Elsevier B.V. Source


Li G.-N.,Southwest University | Li G.-N.,State Key Laboratory of Silkworm Genome Biology | Xia X.-J.,Southwest University | Tang W.-C.,Southwest University | And 3 more authors.
Applied Microbiology and Biotechnology | Year: 2016

The silkworm (Bombyx mori L.) is an ideal model of Lepidoptera. However, the diversity and function of the intestinal microbiota in the gut of silkworm remain largely unknown. Changes in the intestinal microecology in fluoride-resistant strain T6 and fluoride-susceptible strain 734 of the silkworm in response to fluoride exposure were investigated. T6 and 734 were treated with 200 mg/kg fluoride (designated as T6-T and 734-T groups) and deionized water (designated as T6-C and 734-C groups). Culture-dependent approach revealed that the numbers of intestinal bacteria in the 734-T group significantly decreased compared with that in the 734-C group (4.8 ± 0.6 × 107 CFU/mL vs. 7.5 ± 0.7 × 107 CFU/mL; P < 0.05). Analyses of the intestinal content pH showed that the pH decreased in the 734-T group only. Additionally, SCFA concentrations significantly decreased in both treatment groups compared with the control groups. High-throughput sequencing indicated that the intestinal microbiota in the 734-T group was significantly more diverse than those in the other groups. The bacterial community was composed of two dominant groups (Firmicutes and Proteobacteria). Principal component analyses revealed a significant difference in the composition of the intestinal microbiota in the 734-T group compared with those in the other groups. Thaumarchaeota and Euryarchaeota were more abundant in the 734-T group, but they were less abundant in the other groups. This study enhances our understanding about the diversity and function of silkworm intestinal microbiota in response to fluoride exposure among silkworm strains with diverse resistance. © 2016 Springer-Verlag Berlin Heidelberg Source


Datar I.,University of Toledo | Qiu X.,University of Toledo | Ma H.Z.,University of Toledo | Yeung M.,University of Toledo | And 8 more authors.
Oncotarget | Year: 2015

Accumulating evidence suggests that presence of macrophages in the tumor microenvironment add to the invasive and tumor-promoting hallmarks of cancer cells by secreting angiogenic and growth factors. RKIP is a known metastasis suppressor and interferes with several steps of metastasis. However, the mechanistic underpinnings of its function as a broad metastasis suppressor remain poorly understood. Here, we establish a novel pathway for RKIP regulation of metastasis inhibition through the negative regulation of RANTES/CCL5 thereby limiting tumor macrophage infiltration and inhibition of angiogenesis. Using a combination of loss- and gain-of- function approaches, we show that RKIP hinders breast cancer cell invasion by inhibiting expression of the CC chemokine CCL5 in vitro. We also show that the expression levels of RKIP and CCL5 are inversely correlated among clinical human breast cancer samples. Using a mouse allograft breast cancer transplantation model, we highlight that ectopic expression of RKIP significantly decreases tumor vasculature, macrophage infiltration and lung metastases. Mechanistically, we demonstrate that the inhibition of the CCL5 expression is the cause of the observed effects resulting from RKIP expression. Taken together, our results underscore the significance of RKIP as important negative regulator of tumor microenvironment. Source


Chen Z.,State Key Laboratory of Silkworm Genome Biology | Nohata J.,Kirin Brewery Co. | Guo H.,State Key Laboratory of Silkworm Genome Biology | Li S.,State Key Laboratory of Silkworm Genome Biology | And 17 more authors.
Scientific Data | Year: 2015

The silkmoth chorion was studied extensively by F.C. Kafatos' group for almost 40 years. However, the complete structure of the chorion locus was not obtained in the genome sequence of Bombyx mori published in 2008 due to repetitive sequences, resulting in gaps and an incomplete view of the locus. To obtain the complete sequence of the chorion locus, expressed sequence tags (ESTs) derived from follicular epithelium cells were used as probes to screen a bacterial artificial chromosome (BAC) library. Seven BACs were selected to construct a contig which covered the whole chorion locus. By Sanger sequencing, we successfully obtained complete sequences of the chorion locus spanning 871,711 base pairs on chromosome 2, where we annotated 127 chorion genes. The dataset reported here will recruit more researchers to revisit one of the oldest model systems which has been used to study developmentally regulated gene expression. It also provides insights into egg development and fertilization mechanisms and is relevant to applications related to improvements in breeding procedures and transgenesis. Source

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