Spermatogenesis in mammals is characterized by two waves of piRNA expression: one corresponds to classic piRNAs responsible for silencing retrotransponsons and the second wave is predominantly derived from nontransposon intergenic regions in pachytene spermatocytes, but the function of these pachytene piRNAs is largely unknown. Here, we report the involvement of pachytene piRNAs in instructing massive mRNA elimination in mouse elongating spermatids (ES). We demonstrate that a piRNA-induced silencing complex (pi-RISC) containing murine PIWI (MIWI) and deadenylase CAF1 is selectively assembled in ES, which is responsible for inducing mRNA deadenylation and decay via a mechanism that resembles the action of miRNAs in somatic cells. Such a highly orchestrated program appears to take full advantage of the enormous repertoire of diversified targeting capacity of pachytene piRNAs derived from nontransposon intergenic regions. These findings suggest that pachytene piRNAs are responsible for inactivating vast cellular programs in preparation for sperm production from ES.

Authors are able to make the final publisher's version of the article free upon publication via our standard fee. Please note that ASPB retains copyright. Therefore, authors seeking to comply with institutional and other funder (e.g., RCUK) policies may deposit their peer-reviewed accepted manuscript into the appropriate repository for immediate access. Authors who are required to retain copyright and grant to their institution a nonexclusive license to exercise any and all rights under copyright, on a commercial or noncommercial basis, must file for a waiver of the institutional license. AGAMOUS-LIKE6 (AGL6) genes play essential roles in flower development, but whether and how they work with floral organ identity genes remain less understood. Here, we describe interactions of the rice (Oryza sativa) AGL6 gene MADS6 with other rice floral homeotic genes in flower development. Genetic analyses revealed that MADS6 specifies the identity of the three inner whorls and floral meristem determinacy redundantly with SUPERWOMAN1/MADS16 (B-gene) or MADS3 (C-gene). MADS6 was shown to define carpel/ovule development and floral determinacy by interacting with MADS13 (D-gene) and control the palea and floral meristem identities together with the YABBY gene DROOPING LEAF. Expression analyses revealed that the transcript levels of six B-, C-, and E-class genes were reduced in mads6-1 at the early flower developmental stage, suggesting that MADS6 is a key regulator of early flower development. Moreover, MADS6 can directly bind to a putative regulatory motif on MADS58 (C-gene), and mads6-1 mads58 displayed phenotypes similar to that of mads6-1. These results suggest that MADS6 is a key player in specifying flower development via interacting with other floral homeotic genes in rice, thus providing new insights into the mechanism by which flower development is controlled.

BackgroundGallbladder cancer (GBC) is a leading cause of cancer-related death worldwide, and its prognosis remains poor, with 5-year survival of approximately 5%. In this study, we analyzed the involvement of a novel proteoglycan, Sparc/osteonectin, cwcv, and kazal-like domains proteoglycan 1 (SPOCK1), in the tumor progression and prognosis of human GBC.MethodsSPOCK1 expression levels were measured in fresh samples and stored specimens of GBC and adjacent nontumor tissues. The effect of SPOCK1 on cell growth, DNA replication, migration and invasion were explored by Cell Counting Kit-8, colony formation, EdU retention assay, wound healing, and transwell migration assays, flow cytometric analysis, western blotting, and in vivo tumorigenesis and metastasis in nude mice.ResultsSPOCK1 mRNA and protein levels were increased in human GBC tissues compared with those in nontumor tissues. Immunohistochemical analysis indicated that SPOCK1 levels were increased in tumors that became metastatic, compared with those that did not, which was significantly associated with histological differentiation and patients with shorter overall survival periods. Knockdown of SPOCK1 expression by lentivirus-mediated shRNA transduction resulted in significant inhibition of GBC cell growth, colony formation, DNA replication, and invasion in vitro. The knockdown cells also formed smaller xenografted tumors than control GBC cells in nude mice. Overexpression of SPOCK1 had the opposite effects. In addition, SPOCK1 promoted cancer cell migration and epithelial-mesenchymal transition by regulating the expression of relevant genes. We found that activation of the PI3K/Akt pathway was involved in the oncogenic functions of SPOCK1 in GBC.ConclusionsSPOCK1 activates PI3K/Akt signaling to block apoptosis and promote proliferation and metastasis by GBC cells in vitro and in vivo. Levels of SPOCK1 increase with the progression of human GBC. SPOCK1 acts as an oncogene and may be a prognostic factor or therapeutic target for patients with GBC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-014-0276-y) contains supplementary material, which is available to authorized users.

The ability of cancer cells to evade apoptosis may permit survival of a recombinant vaccinia lacking antiapoptotic genes in cancer cells compared with normal cells. We have explored the deletion of two vaccinia virus host range/ antiapoptosis genes, SPI-1 and SPI-2, for their effects on the viral replication and their ability to induce cell death in infected normal and transformed cells in vitro. Indeed, in three paired normal and transformed cell types, the SPI-1 and SPI-2 gene-deleted virus (vSP) preferentially replicates in transformed cells or p53-null cells when compared with their normal counterparts. This selectivity may be derived from the fact that vSP-infected normal cells died faster than infected cancer cells. A fraction of infected cells died with evidence of necrosis as shown by both flow cytometry and detection of high-mobility group B1 protein released from necrotic cells into the culture supernatant. When administered to animals, vSP retains full ability to replicate in tumor tissues, whereas replication in normal tissues is greatly diminished. In a model of viral pathogenesis, mice treated with vSP survived substantially longer when compared with mice treated with the wild-type virus. The mutant virus vSP displayed significant antitumoral effects in an MC38 s.c. tumor model in both nude (P < 0.001) and immunocompetent mice (P < 0.05). We conclude that this recombinant vaccinia vSP shows promise for oncolytic virus therapy. Given its enhanced tumor selectivity, improved safety profile, and substantial oncolytic effects following systemic delivery in murine models, it should also serve as a useful vector for tumor-directed gene therapy. (Cancer Res 2005; 65(21): 9991-8)

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Long noncoding RNAs (lncRNAs) play roles in the development and progression of many cancers; however, the contributions of lncRNAs to human gallbladder cancer (GBC) remain largely unknown. In this study, we identify a group of differentially expressed lncRNAs in human GBC tissues, including prognosis-associated gallbladder cancer lncRNA (lncRNA-PAGBC), which we find to be an independent prognostic marker in GBC Functional analysis indicates that lncRNA-PAGBC promotes tumour growth and metastasis of GBC cells. More importantly, as a competitive endogenous RNA (ceRNA), lncRNA-PAGBC competitively binds to the tumour suppressive microRNAs miR-133b and miR-511. This competitive role of lncRNA-PAGBC is required for its ability to promote tumour growth and metastasis and to activate the AKT/mTOR pathway. Moreover, lncRNA-PAGBC interacts with polyadenylate binding protein cytoplasmic 1 (PABPC1) and is stabilized by this interaction. This work provides novel insight on the molecular pathogenesis of GBC.

During reproductive development, rice plants develop unique flower organs which determine the final grain yield. OsMADS1, one of SEPALLATA-like MADS-box genes, has been unraveled to play critical roles in rice floral organ identity specification and floral meristem determinacy. However, the molecular mechanisms underlying interactions of OsMADS1 with other floral homeotic genes in regulating flower development remains largely elusive. In this work, we studied the genetic interactions of OsMADS1 with B-, C-, and D-class genes along with physical interactions among their proteins. We show that the physical and genetic interactions between OsMADS1 and OsMADS3 are essential for floral meristem activity maintenance and organ identity specification; while OsMADS1 physically and genetically interacts with OsMADS58 in regulating floral meristem determinacy and suppressing spikelet meristem reversion. We provided important genetic evidence to support the neofunctionalization of two rice C-class genes (OsMADS3 and OsMADS58) during flower development. Gene expression profiling and quantitative RT-PCR analyses further revealed that OsMADS1 affects the expression of many genes involved in floral identity and hormone signaling, and chromatin immunoprecipitation (ChIP)-PCR assay further demonstrated that OsMADS17 is a direct target gene of OsMADS1. Taken together, these results reveal that OsMADS1 has diversified regulatory functions in specifying rice floral organ and meristem identity, probably through its genetic and physical interactions with different floral homeotic regulators.

KRAS activation occurring in more than 90% of pancreatic ductal adenocarcinomas (PDAC) drives progression and metastasis, but the underlying mechanisms involved in these processes are still poorly understood. Here, we show how KRAS acts through inflammatory NF-κB signaling to activate the transcription factor YY1, which represses expression of the tumor suppressor gene miR-489. In PDAC cells, repression of miR-489 by KRAS signaling inhibited migration and metastasis by targeting the extracellular matrix factors ADAM9 and MMP7. miR-489 downregulation elevated levels of ADAM9 and MMP7, thereby enhancing the migration and metastasis of PDAC cells. Together, our results establish a pivotal mechanism of PDAC metastasis and suggest miR-489 as a candidate therapeutic target for their attack. Cancer Res; 77(1); 100-11. ©2016 AACR.