Abstract
Background
Previous studies have revealed the key functions of N6-methyladenosine (m6A) modification in breast cancer (BC). MALAT1 as a highly m6A modified lncRNA associated with cancer ...development and metastasis, but the functional relevance of m6A methyltransferase and MALAT1 in BC is still unknown. Here, our study investigated the effects of the novel m6A methyltransferase METTL3 on epithelial-mesenchymal transition (EMT) in BC via the MALAT1/miR-26b/HMGA2 axis.
Methods
Firstly, we collected clinical BC samples and cultured BC cells, and detected mRNA and protein levels in the human samples and human cell lines by RT-qPCR and Western blot, respectively. Then, the binding of MALAT1 and miR-26b and the targeting relationship between miR-26b and HMGA2 were examined by dual-luciferase assay. Moreover, the binding of MALAT1 and miR-26b was tested by RNA pull down and RNA immunoprecipitation (RIP) assays. Methylated-RNA immunoprecipitation (Me-RIP) was used to detect the m6A modification level of MALAT1. The interaction of METTL3 and MALAT1 was detected by photoactivatable ribonucleoside-crosslinking immunoprecipitation (PAR-CLIP). Finally, effects on invasion and migration were detected by Transwell.
Results
In BC, the level of miR-26b was consistently low, while the levels of METTL3, MALAT1 and HMGA2 were high. Further experiments showed that METTL3 up-regulated MALAT1 expression by modulating the m6A modification of MALAT1, and that MALAT1 could promote the expression of HMGA2 by sponging miR-26b. In BC cells, we found that silencing METTL3 could inhibit EMT and tumor cell invasion by suppressing MALAT1. Furthermore, MALAT1 mediated miR-26b to target HMGA2 and promote EMT, migration, and invasion. In summary, METTL3 promoted tumorigenesis of BC via the MALAT1/miR-26b/HMGA2 axis.
Conclusions
Silencing METTL3 down-regulate MALAT1 and HMGA2 by sponging miR-26b, and finally inhibit EMT, migration and invasion in BC, providing a theoretical basis for clinical treatment of BC.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The programmed cell death 1 (PD-1) receptor on the surface of immune cells is an immune checkpoint molecule that mediates the immune escape of tumor cells. Consequently, antibodies targeting PD-1 ...have shown efficacy in enhancing the antitumor activity of T cells in some types of cancers. However, the potential effects of PD-1 on tumor cells remain largely unknown. Here, we show that PD-1 is expressed across a broad range of tumor cells. The silencing of PD-1 or its ligand, PD-1 ligand 1 (PD-L1), promotes cell proliferation and colony formation in vitro and tumor growth in vivo. Conversely, overexpression of PD-1 or PD-L1 inhibits tumor cell proliferation and colony formation. Moreover, blocking antibodies targeting PD-1 or PD-L1 promote tumor growth in cell cultures and xenografts. Mechanistically, the coordination of PD-1 and PD-L1 activates its major downstream signaling pathways including the AKT and ERK1/2 pathways, thus enhancing tumor cell growth. This study demonstrates that PD-1/PD-L1 is a potential tumor suppressor and potentially regulates the response to anti-PD-1/PD-L1 treatments, thus representing a potential biomarker for the optimal cancer immunotherapeutic treatment.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Cholesterol increases the risk of aggressive prostate cancer and has emerged as a potential therapeutic target for prostate cancer. The functional roles of cholesterol in prostate cancer metastasis ...are not fully understood. Here, we found that cholesterol induces the epithelial-to-mesenchymal transition (EMT) through extracellular-regulated protein kinases 1/2 pathway activation, which is mediated by EGFR and adipocyte plasma membrane-associated protein (APMAP) accumulation in cholesterol-induced lipid rafts. Mechanistically, APMAP increases the interaction with EGFR substrate 15-related protein (EPS15R) to inhibit the endocytosis of EGFR by cholesterol, thus promoting cholesterol-induced EMT. Both the mRNA and protein levels of APMAP are upregulated in clinical prostate cancer samples. Together, these findings shed light onto an APMAP/EPS15R/EGFR axis that mediates cholesterol-induced EMT of prostate cancer cells. SIGNIFICANCE: This study delineates the molecular mechanisms by which cholesterol increases prostate cancer progression and demonstrates that the binding of cholesterol-induced APMAP with EPS15R inhibits EGFR internalization and activates ERK1/2 to promote EMT. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/79/12/3063/F1.large.jpg.
A "DNA crunching" linear motor mechanism that employs a grip-and-release transient spring like compression of B- to A-form DNA has been found in our previous studies. Our FRET measurements in vitro ...show a decrease in distance from TerL to portal during packaging; furthermore, there is a decrease in distance between closely positioned dye pairs in the Y-stem of translocating Y-DNA that conforms to B- and A- structure. In normal translocation into the prohead the TerL motor expels all B-form tightly binding YOYO-1 dye that cannot bind A-form. The TerL motor cannot package A-form dsRNA. Our work reported here shows that addition of helper B form DNA:DNA (D:D) 20mers allows increased packaging of heteroduplex A-form DNA:RNA 20mers (D:R), evidence for a B- to A-form spring motor pushing duplex nucleic acid. A-form DNA:RNA 25mers, 30mers, and 35mers alone are efficiently packaged into proheads by the TerL motor showing that a proposed hypothetical dehydration motor mechanism operating on duplex substrates does not provide the packaging motor force. Taken together with our previous studies showing TerL motor protein motion toward the portal during DNA packaging, our present studies of short D:D and D:R duplex nucleic acid substrates strongly supports our previous evidence that the protein motor pushes rather than pulls or dehydrates duplex substrates to provide the translocation into prohead packaging force.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Breast cancer, a multifactorial disease, represents one of the leading causes of cancer-related morbidity and mortality in women. This study set out to elucidate the underlying mechanism by which ...lncRNA UCA1 affects the m6A modification of miR-375 by mediating the DNA methylation of METTL14 and then altering SOX12 expression in breast cancer. First, the expression patterns of lncRNA UCA1, miR-375, and apoptosis-related factors were quantitated by means of RT-qPCR and western blot analysis. In addition, the proliferation, invasion, and apoptosis of cells were detected using CCK-8, Transwell, and flow cytometry, respectively. RIP was performed to further uncover the interaction of lncRNA UCA1 and DNA methyltransferases, and MSP was employed for METTL14 promoter region methylation. The DNA methyltransferase enrichment in the METTL14 promoter region was measured by ChIP. The targeting relationship between miR-375 and SOX12 was confirmed by bioinformatics analysis and dual-luciferase report assay. Lastly, the aforementioned mechanism was also verified using tumor xenograft in vivo. It was found the elevated lncRNA UCA1 expression levels serve as a risk factor of poor prognosis in breast cancer. Meanwhile, silencing lncRNA UCA1 could inhibit the proliferation and invasion, but promote apoptosis of breast cancer cells by reducing the DNA methylation of METTL14 and augmenting its expression. Furthermore, METTL14 was observed to mediate the low miR-375 expression through m6A modification, leading to increased SOX12 expression levels in breast cancer. Altogether, findings obtained in our study indicated that silencing lncRNA UCA1 curbed the progression of breast cancer through the METTL14-miR-375-SOX12 axis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
2′,3′-cGAMP, produced by the DNA sensor cGAS, activates stimulator of interferon genes (STING) and triggers immune response during infection. Tremendous effort has been placed on unraveling the ...mechanism of STING activation. However, little is known about STING inhibition. Here, we found that apo-STING exhibits a bilayer with head-to-head as well as side-by-side packing, mediated by its ligand-binding domain (LBD). This type of assembly holds two endoplasmic reticulum (ER) membranes together not only to prevent STING ER exit but also to eliminate the recruitment of TBK1, representing the autoinhibited state of STING. Additionally, we obtained the filament structure of the STING/2′,3′-cGAMP complex, which adopts a bent monolayer assembly mediated by LBD and transmembrane domain (TMD). The active, curved STING polymer could deform ER membrane to support its ER exit and anterograde transportation. Our data together provide a panoramic vision regarding STING autoinhibition and activation, which adds substantially to current understanding of the cGAS-STING pathway.
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•Apo-STING exists as oligomer in the cell•Apo-STING oligomer adopts a bilayer with head-to-head and side-by-side packing of LBD•Apo-STING bilayer is crucial for STING ER retention and autoinhibition•Activated STING filament displays a bent conformation mediated by LBD and TMD
Liu et al. show that apo-STING forms oligomers with bilayer assembly zippering two ER membranes in the resting state whereby STING fulfills its ER retention and autoinhibition. The activated STING filament adopts a bent conformation that deforms the membrane, which is fit for its anterograde transportation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Breast cancer, a multifactorial disease, represents one of the leading causes of cancer-related morbidity and mortality in women. This study set out to elucidate the underlying mechanism by which ...lncRNA UCA1 affects the m
A modification of miR-375 by mediating the DNA methylation of METTL14 and then altering SOX12 expression in breast cancer. First, the expression patterns of lncRNA UCA1, miR-375, and apoptosis-related factors were quantitated by means of RT-qPCR and western blot analysis. In addition, the proliferation, invasion, and apoptosis of cells were detected using CCK-8, Transwell, and flow cytometry, respectively. RIP was performed to further uncover the interaction of lncRNA UCA1 and DNA methyltransferases, and MSP was employed for METTL14 promoter region methylation. The DNA methyltransferase enrichment in the METTL14 promoter region was measured by ChIP. The targeting relationship between miR-375 and SOX12 was confirmed by bioinformatics analysis and dual-luciferase report assay. Lastly, the aforementioned mechanism was also verified using tumor xenograft in vivo. It was found the elevated lncRNA UCA1 expression levels serve as a risk factor of poor prognosis in breast cancer. Meanwhile, silencing lncRNA UCA1 could inhibit the proliferation and invasion, but promote apoptosis of breast cancer cells by reducing the DNA methylation of METTL14 and augmenting its expression. Furthermore, METTL14 was observed to mediate the low miR-375 expression through m
A modification, leading to increased SOX12 expression levels in breast cancer. Altogether, findings obtained in our study indicated that silencing lncRNA UCA1 curbed the progression of breast cancer through the METTL14-miR-375-SOX12 axis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We have identified DNA polymorphisms in the gene of insulin-like growth factor 2 by PCR-SSCP in a resource population, which was generated by Silky reciprocally crossing to Broilers. A C --> G ...mutation was detected in the exon 2 (at position 71) by sequencing. This single nucleotide polymorphism (SNP) was found to be associated with production traits. Chicken with BB genotype showed more chest angle width but less 3 week body weight and glandular stomach weight than chicken with AA genotype (P < 0.05); while the heterozygote (AB genotype) chicken had more abdominal fat weight, eviscerated yield with giblet than AA homozygote chicken. Further analysis showed that there were different genetic effects on some traits between heterozygote AB (paternal allele given first) and heterozygote BA: chickens with genotype BA had more birth weight and breast weight but less abdominal fat weight than chickens with genotype AB (P < 0.05), which could be hypothetically contributed by genome imprinting. Therefore, Silky chickens were selected for production of heterozygotes to confirm whether IGF2 locus was imprinting. Progeny from heterozygote x homozygote reciprocal cross was assayed for expression after the genotype was determined. The transcription of IGF2 was detected by RT-PCR-SSCP. IGF2 gene was expressed bialleleically in 1-day-old neonatal liver and 90-day-old liver, kidney, heart, and muscle of both heterozygote AB and BA chickens. Therefore, IGF2 was not an imprinting gene in chicken. The different genetic effects between the heterozygote AB and BA remain to be elucidated.
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