MicroRNA-122 (miR-122), which accounts for 70% of the liver's total miRNAs, plays a pivotal role in the liver. However, its intrinsic physiological roles remain largely undetermined. We demonstrated ...that mice lacking the gene encoding miR-122a (Mir122a) are viable but develop temporally controlled steatohepatitis, fibrosis, and hepatocellular carcinoma (HCC). These mice exhibited a striking disparity in HCC incidence based on sex, with a male-to-female ratio of 3.9:1, which recapitulates the disease incidence in humans. Impaired expression of microsomal triglyceride transfer protein (MTTP) contributed to steatosis, which was reversed by in vivo restoration of Mttp expression. We found that hepatic fibrosis onset can be partially attributed to the action of a miR-122a target, the Klf6 transcript. In addition, Mir122a(-/-) livers exhibited disruptions in a range of pathways, many of which closely resemble the disruptions found in human HCC. Importantly, the reexpression of miR-122a reduced disease manifestation and tumor incidence in Mir122a(-/-) mice. This study demonstrates that mice with a targeted deletion of the Mir122a gene possess several key phenotypes of human liver diseases, which provides a rationale for the development of a unique therapy for the treatment of chronic liver disease and HCC.
Latrophilin-2 (Lphn2) and latrophilin-3 (Lphn3) are adhesion GPCRs that serve as postsynaptic recognition molecules in CA1 pyramidal neurons of the hippocampus, where they are localized to distinct ...dendritic domains and are essential for different sets of excitatory synapses. Here, we studied Lphn2 and Lphn3 in the cerebellum. We show that latrophilins are abundantly and differentially expressed in the cerebellar cortex. Using conditional KO mice, we demonstrate that the Lphn2/3 double-deletion but not the deletion of Lphn2 or Lphn3 alone suppresses parallel-fiber synapses and reduces parallel-fiber synaptic transmission by ~50% without altering release probability. Climbing-fiber synapses, conversely, were unaffected. Even though ~50% of total cerebellar Lphn3 protein is expressed in Bergmann glia, Lphn3 deletion from Bergmann glia did not detectably impair excitatory or inhibitory synaptic transmission. Our studies demonstrate that Lphn2 and Lphn3 are selectively but redundantly required in Purkinje cells for parallel-fiber synapses.
Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide due to metastasis. Paraspeckle component 1 (PSPC1) upregulation has been identified as an HCC pro-metastatic activator ...associated with poor patient prognosis, but with a lack of targeting strategy. Here, we report that PSPC1, a nuclear substrate of PTK6, sequesters PTK6 in the nucleus and loses its metastasis driving capability. Conversely, PSPC1 upregulation or PSPC1-Y523F mutation promotes epithelial-mesenchymal transition, stemness, and metastasis via cytoplasmic translocation of active PTK6 and nuclear translocation of β-catenin, which interacts with PSPC1 to augment Wnt3a autocrine signaling. The aberrant nucleocytoplasmic shuttling of active PTK6/β-catenin is reversed by expressing the PSPC1 C-terminal interacting domain (PSPC1-CT131), thereby suppressing PSPC1/PTK6/β-catenin-activated metastasis to prolong the survival of HCC orthotopic mice. Thus, PSPC1 is the contextual determinant of the oncogenic switch of PTK6/β-catenin subcellular localizations, and PSPC1-CT131 functions as a dual inhibitor of PSPC1 and PTK6 with potential for improving cancer therapy.
Cadherins contribute to the organization of nearly all tissues, but the functions of several evolutionarily conserved cadherins, including those of calsyntenins, remain enigmatic. Puzzlingly, two ...distinct, non-overlapping functions for calsyntenins were proposed: As postsynaptic neurexin ligands in synapse formation, or as presynaptic kinesin adaptors in vesicular transport. Here, we show that, surprisingly, acute CRISPR-mediated deletion of calsyntenin-3 in mouse cerebellum in vivo causes a large decrease in inhibitory synapse, but a robust increase in excitatory parallel-fiber synapses in Purkinje cells. As a result, inhibitory synaptic transmission was suppressed, whereas parallel-fiber synaptic transmission was enhanced in Purkinje cells by the calsyntenin-3 deletion. No changes in the dendritic architecture of Purkinje cells or in climbing-fiber synapses were detected. Sparse selective deletion of calsyntenin-3 only in Purkinje cells recapitulated the synaptic phenotype, indicating that calsyntenin-3 acts by a cell-autonomous postsynaptic mechanism in cerebellum. Thus, by inhibiting formation of excitatory parallel-fiber synapses and promoting formation of inhibitory synapses in the same neuron, calsyntenin-3 functions as a postsynaptic adhesion molecule that regulates the excitatory/inhibitory balance in Purkinje cells.
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•Large-scale comparative transcriptomics analysis of hepatocellular carcinoma reveals 664 prognostic comparative HCC (pcHCC) genes.•pcHCC genes included novel targets with potential ...utility in sorafenib combination therapies.•Knockdown of the selective pcHCC genes NCAPG and CENPW downregulated the p38/STAT3 axis to enhance sorafenib combination treatments.
With the increasing incidence and mortality of human hepatocellular carcinoma (HCC) worldwide, revealing innovative targets to improve therapeutic strategies is crucial for prolonging the lives of patients. To identify innovative targets, we conducted a comprehensive comparative transcriptome analysis of 5,410 human HCCs and 974 mouse liver cancers to identify concordantly expressed genes associated with patient survival. Among the 664 identified prognostic comparative HCC (pcHCC) genes, upregulated pcHCC genes were associated with prognostic clinical features, including large tumor size, vascular invasion and late HCC stages. Interestingly, after validating HCC patient prognoses in multiple independent datasets, we matched the 664 aberrant pcHCC genes with the sorafenib-altered genes in TCGA_LIHC patients and found these 664 pcHCC genes were enriched in sorafenib-related functions, such as downregulated xenobiotic and lipid metabolism and upregulated cell proliferation. Therapeutic agents targeting aberrant pcHCC genes presented divergent molecular mechanisms, including suppression of sorafenib-unrelated oncogenic pathways, induction of sorafenib-unrelated ferroptosis, and modulation of sorafenib transportation and metabolism, to potentiate sorafenib therapeutic effects in HCC combination therapy. Moreover, the pcHCC genes NCAPG and CENPW, which have not been targeted in combination with sorafenib treatment, were knocked down and combined with sorafenib treatment, which reduced HCC cell viability based on disruption to the p38/STAT3 axis, thereby hypersensitizing HCC cells. Together, our results provide important resources and reveal that 664 pcHCC genes represent innovative targets suitable for developing therapeutic strategies in combination with sorafenib based on the divergent synergistic mechanisms for HCC tumor suppression.
Abstract
Precise noncoding RNA (ncRNA)-based network prediction is necessary to reveal ncRNA functions and pathological mechanisms. Here, we established a systemic pipeline to identify prognostic ...ncRNAs, predict their functions and explore their pathological mechanisms in lung adenocarcinoma (LUAD). After in silico and experimental validation based on evaluations of prognostic value in multiple LUAD cohorts, we selected the PTTG3P pseudogene from among other prognostic ncRNAs (MIR497HG, HSP078, TBX5-AS1, LOC100506990 and C14orf64) for mechanistic studies. PTTG3P upregulation in LUAD cells shortens the metaphase to anaphase transition in mitosis, increases cell viability after cisplatin or paclitaxel treatment, facilitates tumor growth that leads to poor survival in orthotopic lung models, and is associated with a poor survival rate in LUAD patients in the TCGA cohort who received chemotherapy. Mechanistically, PTTG3P acts as an ncRNA that interacts with the transcription factor FOXM1 to regulate the transcriptional activation of the mitotic checkpoint kinase BUB1B, which augments tumor growth and chemoresistance and leads to poor outcomes for LUAD patients. Overall, we established a systematic strategy to uncover prognostic ncRNAs with functional prediction methods suitable for pan-cancer studies. Moreover, we revealed that PTTG3P, due to its upregulation of the PTTG3P/FOXM1/BUB1B axis, could be a therapeutic target for LUAD patients.
Berberine (Brb) is an active alkaloid occurring in various common plant species, with well-recognized potential for cancer therapy. Brb not only augments the efficacy of antineoplastic chemotherapy ...and radiotherapy but also exhibits direct antimitotic and proapoptotic actions, along with distinct antiangiogenic and antimetastatic activities in a variety of tumors. Despite its low systemic toxicity, several pharmaceutical challenges limit the application of Brb in cancer therapy (ie, extremely low solubility and permeability, very poor pharmacokinetics (PKs), and oral bioavailability). Among lipid-based nanocarriers investigated recently for Brb, stealth amphiphilic micelles of polymeric phospholipid conjugates were studied here as a promising strategy to improve Brb delivery to tumors. Specifically, physicochemically stable micelles made of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy(polyethyleneglycol)-2000 (PEG-PE) mixed with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) (PEG-succinate ester of vitamin E), in a 3:1 M ratio, increased Brb solubilization by 300%. Our PEG-PE/TPGS-mixed micelles firmly retained the incorporated Brb, displaying extended-release profile in simulated media, with up to 30-fold projected improvement in simulated PKs of Brb. Owing to the markedly better uptake of Brb-containing mixed micelles in vitro, our Brb-mixed micelles nanoformulation significantly amplified apoptosis and overall cytotoxic effectiveness against monolayer and spheroid cultures of human prostate carcinomas (16- to 18-fold lower half-maximal inhibitory concentration values in PC3 and LNPaC, respectively), compared to free Brb. Mixed PEG-PE/TPGS micelles represent a promising delivery platform for the sparingly soluble anticancer agent, Brb, encouraging further pharmaceutical development of this drug for cancer therapy.
The tumor microenvironment plays an important role in tumor growth and metastasis. However, the mechanism by which tumor cells regulate the cell and non-cell constituents of surrounding stroma ...remains incompletely understood. Promyelocytic leukemia (PML) is a pleiotropic tumor suppressor, but its role in tumor microenvironment regulation is poorly characterized. PML is frequently downregulated in many cancer types, including lung cancer. Here, we identify a PML ubiquitination pathway that is mediated by WD repeat 4-containing cullin-RING ubiquitin ligase 4 (CRL4WDR4). Clinically, this PML degradation pathway is hyperactivated in lung cancer and correlates with poor prognosis. The WDR4/PML axis induces a set of cell-surface or secreted factors, including CD73, urokinase-type plasminogen activator receptor (uPAR), and serum amyloid A2 (SAA2), which elicit paracrine effects to stimulate migration, invasion, and metastasis in multiple lung cancer models. In xenograft and genetically engineered mouse models, the WDR4/PML axis elevates intratumoral Tregs and M2-like macrophages and reduces CD8+ T cells to promote lung tumor growth. These immunosuppressive effects were all reversed by CD73 blockade. Our study identifies WDR4 as an oncoprotein that negatively regulates PML via ubiquitination to promote lung cancer progression by fostering an immunosuppressive and prometastatic tumor microenvironment, suggesting the potential of immune-modulatory approaches for treating lung cancer with aberrant PML degradation.
The synapse is the fundamental unit of the brain that enables information processing within circuits of interconnected neurons. The molecular mechanisms of synapse formation and function are critical ...for brain development and function, in health and in disease. Synaptic cell-adhesion is an essential feature of synapses that has been shown to regulate synapse number, control synaptic properties and affect downstream behaviors. Careful study of the molecular participants in synaptic cell-adhesion and how they work to specify and regulate synapses is needed to reach a molecular-level understanding of the synapses underlying particular circuits and behaviors and may lead the way to novel therapeutic approaches for brain disorders.The latrophilins (Lphns) and teneurins (Tens) are two families of cell-adhesion molecules that are expressed at synapses and interact in a trans- conformation. The latrophilin isoforms Lphn2 and Lphn3 have been shown to be postsynaptic regulators of excitatory synapse number and transmission in mouse hippocampus that function in an input-specific manner, while various Ten orthologs have been shown to be important for proper axonal targeting and are capable of inducing postsynaptic structures in vitro. These data suggest that the latrophilin-teneurin interaction may be a critical mechanism underlying synapse formation and function, however much remains to be learned about how latrophilins and teneurins function at synapses. First, it is unclear if the principles of latrophilin function identified in the hippocampus hold true in other neurons and brain regions that exhibit different patterns of latrophilin expression. In addition, no rigorous studies of teneurin function at synapses in vivo have been performed to date. Finally, there is only limited evidence that latrophilins and teneurins act together to control synapse number and/or function from experiments performed at the same synapses in vivo.This dissertation will cover my progress in dissecting the functions of latrophilins and teneurins at synapses. In Chapter 1, I review in detail the importance of studying the molecular code of synaptic cell-adhesion and the literature to date on latrophilins and teneurins. In Chapter 2, I present a study of the functions of Lphn2 and Lphn3 at Purkinje cell synapses in the cerebellum, where I characterize the expression of Lphns in cerebellum and demonstrate that Lphn2/3 are redundant but essential for parallel-fiber synapse number and synaptic transmission. In Chapter 3, I detail introductory work dissecting the function of Ten3 at synapses between proximal CA1 to distal subiculum neurons, where I find that postsynaptic Ten3 in distal subiculum neurons is not important for maintenance of synaptic strength at synapses from proximal CA1. Taken together, this work expands on our understanding of latrophilins and teneurins as critical mediators of synapse number and function
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