The association of transcription factor Prox1 with the proliferation, migration, and invasion of lung cancer.

BACKGROUND: The current study investigates the effect of transcription factor Prox1 on the proliferation, migration, and invasion ability of lung cancer. METHODS: Lung cancer cell lines (A549 and H446 cells) were transfected with Prox1NAD and siRNA, respectively. Thus, the A549 and H446 cells overexpressed Prox1 after transfection of Prox1NAD plasmids, and A549 and H446 cells have low expression of Prox1 after transfection with siRNA. Reverse transcriptase quantitative PCR and western blot analyses were used to detect Prox1 mRNA and protein expression in cells. Plate clone formation experiments and MTT experiments were used to detect cell proliferation. Western blot was used to detect the expression of Rho family-related proteins in cells. RESULTS: Compared to untransfected wild-type A549 and H446 that served as blank controls, the expression level of Prox1mRNA and protein in A549 and H446 cells overexpressing Prox1 after plasmid transfection was high, while the expression level of Prox1mRNA and protein in A549 and H446 cells with low expression of Prox1 after siRNA transfection was low. With the increase of Prox1 expression, the expression of RhoA and RhoC increased, while the expression of RhoB decreased. CONCLUSION: The finding of this study may provide a new approach for the treatment of lung cancer using targeted gene therapy.

Adoptive cellular immunotherapy of tumors via effective CpG delivery to dendritic cells using dendrimer-entrapped gold nanoparticles as a gene vector.

The major obstacle that hinders current cancer immunotherapies is the development of an effective approach to promote a proper immune response for effective tumor killing through activated T cells. Herein, we report an effective T cell-based tumor immunotherapy approach through nonviral delivery of a cytosine-guanine (CpG) oligonucleotide using dendrimer-entrapped gold nanoparticles (Au DENPs). In our work, Au DENPs partially decorated with methoxy polyethylene glycol (mPEG) were synthesized and characterized to be used as a vector for CpG delivery to bone marrow-derived dendritic cells (BMDCs). The BMDCs matured via CpG delivery were used to activate T cells for adoptive immunotherapy of cancer cells. We show that the developed PEGylated Au DENPs are able to effectively transfect CpG leading to the maturation of BMDCs that can be used to activate T cells for subsequent adoptive immunotherapy of cancer cells in vitro and a xenografted melanoma tumor model in vivo after intravenous injection. Importantly, the developed approach to genetically engineer BMDCs enables a triggered adaptive immune response and memory of T cells, which can be beneficial for effective inhibition of tumor metastasis and recurrence. The developed nonviral gene delivery approach using Au DENPs as a vector for T cell-based immunotherapy can be applied to different cancer types.

Yeast mismatch repair components are required for stable inheritance of gene silencing.

Alterations in epigenetic silencing have been associated with ageing and tumour formation. Although substantial efforts have been made towards understanding the mechanisms of gene silencing, novel regulators in this process remain to be identified. To systematically search for components governing epigenetic silencing, we developed a genome-wide silencing screen for yeast (Saccharomyces cerevisiae) silent mating type locus HMR. Unexpectedly, the screen identified the mismatch repair (MMR) components Pms1, Mlh1, and Msh2 as being required for silencing at this locus. We further found that the identified genes were also required for proper silencing in telomeres. More intriguingly, the MMR mutants caused a redistribution of Sir2 deacetylase, from silent mating type loci and telomeres to rDNA regions. As a consequence, acetylation levels at histone positions H3K14, H3K56, and H4K16 were increased at silent mating type loci and telomeres but were decreased in rDNA regions. Moreover, knockdown of MMR components in human HEK293T cells increased subtelomeric DUX4 gene expression. Our work reveals that MMR components are required for stable inheritance of gene silencing patterns and establishes a link between the MMR machinery and the control of epigenetic silencing.

Stem cell-mediated delivery of nanogels loaded with ultrasmall iron oxide nanoparticles for enhanced tumor MR imaging.

The development of new nanoplatforms with enhanced tumor accumulation for accurate diagnosis still remains a great challenge in current precision nanomedicine. Herein, we report the design of stem cell-mediated delivery of nanogels (NGs) loaded with ultrasmall iron oxide (Fe3O4) nanoparticles (NPs) for enhanced magnetic resonance (MR) imaging of tumors. In this study, sodium citrate-stabilized ultrasmall Fe3O4 NPs with a size of 3.16 ± 1.30 nm were first synthesized using a solvothermal route, coated with polyethyleneimine (PEI), and used as crosslinkers to crosslink alginate (AG) NGs formed via a double emulsion approach, where the AG carboxyl groups were pre-activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The thus prepared Fe3O4 NP-loaded NGs (AG/PEI-Fe3O4 NGs) with a size of 47.68 ± 3.41 nm are water-dispersible, colloidally stable, cytocompatible in a given concentration range, display a relatively high r1 relaxivity (r1 = 1.5 mM-1 s-1), and are able to be taken up by bone mesenchymal stem cells without compromising cell viability and stem cell characteristics. Due to the tumor-chemotaxis or tumor tropism, the BMSCs are able to mediate the enhanced delivery of AG/PEI-Fe3O4 NGs to the tumor site after intravenous injection, thus enabling significantly strengthened MR imaging of tumors when compared to free NGs. These findings suggest that the developed AG/PEI-Fe3O4NGs, once mediated by stem cells may serve as a novel, safe, effective and targeted platform for enhanced MR imaging of tumors.

Role of the ribosomal quality control machinery in nucleocytoplasmic translocation of polyQ-expanded huntingtin exon-1.

The subcellular localization of polyQ-expanded huntingtin exon1 (Httex1) modulates polyQ toxicity in models of Huntington's disease. Using genome-wide screens in a yeast model system, we report that the ribosome quality control (RQC) machinery, recently implicated in neurodegeneration, is a key determinant for the nucleocytoplasmic distribution of Httex1-103Q. Deletion of the RQC genes, LTN1 or RQC1, caused the accumulation of Httex1-103Q in the nucleus through a process that required the CAT-tail tagging activity of Rqc2 and transport via the nuclear pore complex. We provide evidence that nuclear accumulation of Httex1-103Q enhances its cytotoxicity, suggesting that the RQC machinery plays an important role in protecting cells against the adverse effects of polyQ expansion proteins.

Differential effects of soluble and aggregating polyQ proteins on cytotoxicity and type-1 myosin-dependent endocytosis in yeast.

Huntington's disease develops when the polyglutamine (polyQ) repeat in the Huntingtin (Htt) protein is expanded to over 35 glutamines rendering it aggregation-prone. Here, using Htt exon-1 as a polyQ model protein in a genome-wide screen in yeast, we show that the normal and soluble Htt exon-1 is toxic in cells with defects in type-1 myosin-dependent endocytosis. The toxicity of Htt is linked to physical interactions with type-1 myosins, which occur via the Htt proline-rich region, leading to a reduction in actin patch polarization and clathrin-dependent endocytosis. An expansion of the polyQ stretch from 25 to 103 glutamines, which causes Htt aggregation, alleviated Htt toxicity in cells lacking Myo5 or other components involved in early endocytosis. The data suggest that the proline-rich stretch of Htt interacts with type-1 myosin/clathrin-dependent processes and demonstrate that a reduction in the activity of such processes may result in a positive selection for polyQ expansions.

Life-span extension by a metacaspase in the yeast Saccharomyces cerevisiae.

Single-cell species harbor ancestral structural homologs of caspase proteases, although the evolutionary benefit of such apoptosis-related proteins in unicellular organisms is unclear. Here, we found that the yeast metacaspase Mca1 is recruited to the insoluble protein deposit (IPOD) and juxtanuclear quality-control compartment (JUNQ) during aging and proteostatic stress. Elevating MCA1 expression counteracted accumulation of unfolded proteins and aggregates and extended life span in a heat shock protein Hsp104 disaggregase- and proteasome-dependent manner. Consistent with a role in protein quality control, genetic interaction analysis revealed that MCA1 buffers against deficiencies in the Hsp40 chaperone YDJ1 in a caspase cysteine-dependent manner. Life-span extension and aggregate management by Mca1 was only partly dependent on its conserved catalytic cysteine, which suggests that Mca1 harbors both caspase-dependent and independent functions related to life-span control.

Absence of mitochondrial translation control proteins extends life span by activating sirtuin-dependent silencing.

Altered mitochondrial functionality can extend organism life span, but the underlying mechanisms are obscure. Here we report that inactivating SOV1, a member of the yeast mitochondrial translation control (MTC) module, causes a robust Sir2-dependent extension of replicative life span in the absence of respiration and without affecting oxidative damage. We found that SOV1 interacts genetically with the cAMP-PKA pathway and the chromatin remodeling apparatus. Consistently, Sov1p-deficient cells displayed reduced cAMP-PKA signaling and an elevated, Sir2p-dependent, genomic silencing. Both increased silencing and life span extension in sov1Δ cells require the PKA/Msn2/4p target Pnc1p, which scavenges nicotinamide, a Sir2p inhibitor. Inactivating other members of the MTC module also resulted in Sir2p-dependent life span extension. The data demonstrate that the nuclear silencing apparatus senses and responds to the absence of MTC proteins and that this response converges with a pathway for life span extension elicited by reducing TOR signaling.