Hepatocellular cancer (HCC) remains a significant therapeutic challenge due to poorly understood molecular basis. In the current study, we investigate two independent cohorts of 249 and 194 HCC cases for any combinatorial molecular aberrations. Specifically we assessed for simultaneous HMET expression or hMet activation and CTNNB1 mutations to address any concomitant Met and Wnt signaling. To investigate cooperation in tumorigenesis, we co-expressed hMet and β-catenin point-mutants (S33Y or S45Y) in hepatocytes using sleeping beauty (SB) transposon/transposase and hydrodynamic tail vein injection and characterized tumors for growth, signaling, gene signatures and similarity to human HCC. Missense mutations in exon-3 of CTNNB1 were identified in subsets of HCC patients. Irrespective of amino acid affected, all exon-3 mutations induced similar changes in gene expression. Concomitant HMET overexpression or hMet activation, and CTNNB1 mutations, were evident in 9-12.5% of HCCs. Co-expression of hMet and mutant-β-catenin led to notable HCC in mice. Tumors showed active Wnt and hMet signaling with evidence of glutamine synthetase and cyclin-D1 positivity and MAPK/ERK, AKT/Ras/mTOR activation. Introduction of dominant-negative TCF4 prevented tumorigenesis. The gene expression of mouse tumors in hMet-mutant-β-catenin showed high correlation with subsets of human HCC displaying concomitant hMet activation signature and CTNNB1 mutations. In conclusion, we have identified co-operation of hMet and β-catenin activation in a subset of HCC patients and modeled this human disease in mice with a significant transcriptomic intersection. This model will provide novel insight into the biology of this tumor and allow us to evaluate novel therapies as a step towards precision medicine.

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Highlights d Ablation of HuR in NSCs impairs adult but not embryonic neurogenesis d Nuclear translocation of HuR is required for adult neurogenesis d HuR regulates neurogenesis through modulating the FAK premRNA splicing switch d Inhibition of FAK activity rescues defective adult neurogenesis in HuR-deficient mice

Human immunodeficiency viruses (HIVs) are retroviruses that replicate effectively in human CD4+ cells and cause the development of acquired immune deficiency syndrome (AIDS). On the other hand, type 1 long interspersed elements (LINE-1s or L1s) are the only active retroelements that can replicate autonomously in human cells. They, along with other active yet nonautonomous retroelements, have been associated with autoimmune diseases. There are many similarities between HIV and LINE-1. Being derived (or evolved) from ancient retroviruses, both HIV and LINE-1 replicate through a process termed reverse transcription, activate endogenous DNA and RNA sensors, trigger innate immune activation to promote interferon (IFN) expression, and are suppressed by protein products of interferon-stimulated genes (ISGs). However, these similarities make it difficult to decipher or even speculate the relationship between HIV and LINE-1, especially regarding the involvement of the IFN signaling system. In this review, we summarize previous findings on the relationships between HIV and innate immune activation as well as between LINE-1 and IFN upregulation. We also attempt to elucidate the interplay among HIV, LINE-1, and the IFN signaling system in hopes of guiding future research directions for viral suppression and immune regulation.