Cancer associated fibroblasts (CAFs) are key stroma cells that play dominant roles in tumor progression. However, the CAFs-derived molecular determinants that regulate colorectal cancer (CRC) ...metastasis and chemoresistance have not been fully characterized.
CAFs and NFs were obtained from fresh CRC and adjacent normal tissues. Exosomes were isolated from conditioned medium and serum of CRC patients using ultracentrifugation method and ExoQuick Exosome Precipitation Solution kit, and characterized by transmission electronic microscopy, nanosight and western blot. MicroRNA microarray was employed to identify differentially expressed miRNAs in exosomes secreted by CAFs or NFs. The internalization of exosomes, transfer of miR-92a-3p was observed by immunofluorescence. Boyden chamber migration and invasion, cell counting kit-8, flow cytometry, plate colony formation, sphere formation assays, tail vein injection and primary colon cancer liver metastasis assays were employed to explore the effect of NFs, CAFs and exosomes secreted by them on epithelial-mesenchymal transition, stemness, metastasis and chemotherapy resistance of CRC. Luciferase report assay, real-time qPCR, western blot, immunofluorescence, and immunohistochemistry staining were employed to explore the regulation of CRC metastasis and chemotherapy resistance by miR-92a-3p, FBXW7 and MOAP1.
CAFs promote the stemness, epithelial-mesenchymal transition (EMT), metastasis and chemotherapy resistance of CRC cells. Importantly, CAFs exert their roles by directly transferring exosomes to CRC cells, leading to a significant increase of miR-92a-3p level in CRC cells. Mechanically, increased expression of miR-92a-3p activates Wnt/β-catenin pathway and inhibits mitochondrial apoptosis by directly inhibiting FBXW7 and MOAP1, contributing to cell stemness, EMT, metastasis and 5-FU/L-OHP resistance in CRC. Clinically, miR-92a-3p expression is significantly increased in CRC tissues and negatively correlated with the levels of FBXW7 and MOAP1 in CRC specimens, and high expression of exosomal miR-92a-3p in serum was highly linked with metastasis and chemotherapy resistance in CRC patients.
CAFs secreted exosomes promote metastasis and chemotherapy resistance of CRC. Inhibiting exosomal miR-92a-3p provides an alternative modality for the prediction and treatment of metastasis and chemotherapy resistance in CRC.
Summary
Background
Acral melanoma (AM) is the most common histopathological subtype of malignant melanoma in Asians. However, differences in the mutational profiles underlying AM and nonacral ...cutaneous melanoma (NAM) in Asians are not well understood.
Objectives
To augment the understanding of the prevalence, patterns and associations of various mutations between different subtypes of melanoma.
Methods
We performed comprehensive genomic profiling of 409 cancer‐associated genes, using next‐generation sequencing, in 66 primary melanomas comprised of 45 AMs and 21 NAMs.
Results
Most of the AMs (n = 27/45; 60%), but only five of 21 (24%) NAMs, were triple wild‐type (triple‐WT) tumours. Compared with AMs, NAMs exhibited a significantly higher frequency of BRAF mutations. The frequencies of NRAS/KRAS mutations, cell‐cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and gains of receptor tyrosine kinase genes were significantly higher in AMs. Ulceration was found at significantly higher rates in the AMs and NAMs with cell‐cycle aberrations and gains of receptor tyrosine kinase genes. Notably, cell‐cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma‐specific survival in the 66 patients with melanoma and especially in the 45 patients with AM. Multivariate analysis showed that lymph node metastasis and cell‐cycle aberrations were independent prognostic factors of melanoma‐specific survival.
Conclusions
This study strengthens our understanding of the patterns and clinical associations of oncogenic mutations in AMs and NAMs in Asians.
What's already known about this topic?
Mutation frequencies of driver genes vary between melanoma subtypes.
Acral melanoma is the most common subtype of melanoma in Asians.
KIT mutations and copy number variations occur more frequently in the acral subtype of melanoma than in the nonacral subtype
What does this study add?
NRAS/KRAS mutations, cell‐cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and amplifications of receptor tyrosine kinase genes were significantly enriched in acral melanoma and could be potential targets for treatment.
Melanomas with cell‐cycle aberrations and gains in receptor tyrosine kinase genes were significantly more likely to contain ulceration.
What is the translational message?
Cell‐cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma‐specific survival.
These observations should be explored further for future drug development.
Linked Comment: Johansson. Br J Dermatol 2020; 182:1085.
Plain language summary available online
Advances in synthetic biology have led to an arsenal of proof-of-principle bacterial circuits that can be leveraged for applications ranging from therapeutics to bioproduction. A unifying challenge ...for most applications is the presence of selective pressures that lead to high mutation rates for engineered bacteria. A common strategy is to develop cloning technologies aimed at increasing the fixation time for deleterious mutations in single cells. We adopt a complementary approach that is guided by ecological interactions, whereby cyclical population control is engineered to stabilize the functionality of intracellular gene circuits. Three strains of
were designed such that each strain could kill or be killed by one of the other two strains. The resulting "rock-paper-scissors" dynamic demonstrates rapid cycling of strains in microfluidic devices and leads to an increase in the stability of gene circuit functionality in cell culture.
Oncogene MYC is highly expressed in many human cancers and functions as a global regulator of ribosome biogenesis. Previously, we reported that ribosomal protein (RP) L11 binds to c-Myc and inhibits ...its transcriptional activity in response to ribosomal stress. Here, we show that RPL5, co-operatively with RPL11, guides the RNA-induced silencing complex (RISC) to c-Myc mRNA and mediates the degradation of the mRNA, consequently leading to inhibition of c-Myc activity. Knocking down of RPL5 induced c-Myc expression at both mRNA and protein levels, whereas overexpression of RPL5 suppressed c-Myc expression and activity. Immunoprecipitation revealed that RPL5 binds to 3'UTR of c-Myc mRNA and two subunits of RISC, TRBP (HIV-1 TAR RNA-binding protein) and Ago2, mediating the targeting of c-Myc mRNA by miRNAs. Interestingly, RPL5 and RPL11 co-resided on c-Myc mRNA and suppressed c-Myc expression co-operatively. These findings uncover a mechanism by which these two RPs can co-operatively suppress c-Myc expression, allowing a tightly controlled ribosome biogenesis in cells.
The last decade has seen bacteria at the forefront of biotechnological innovation, with applications including biomolecular computing, living therapeutics, microbiome engineering and microbial ...factories. These emerging applications are all united by the need to precisely control complex microbial dynamics in spatially extended environments, requiring tools that can bridge the gap between intracellular and population-level coordination. To address this need, we engineer an inducible quorum sensing system which enables precise tunability of bacterial dynamics both at the population and community level. As a proof-of-principle, we demonstrate the advantages of this system when genetically equipped for cargo delivery. In addition, we exploit the absence of cross-talk with respect to the majority of well-characterized quorum sensing systems to demonstrate inducibility of multi-strain communities. More broadly, this work highlights the unexplored potential of remotely inducible quorum sensing systems which, coupled to any gene of interest, may facilitate the translation of circuit designs into applications.
A synthetic pathway was engineered in Escherichia coli to produce isopropanol by expressing various combinations of genes from Clostridium acetobutylicum ATCC 824, E. coli K-12 MG1655, Clostridium ...beijerinckii NRRL B593, and Thermoanaerobacter brockii HTD4. The strain with the combination of C. acetobutylicum thl (acetyl-coenzyme A CoA acetyltransferase), E. coli atoAD (acetoacetyl-CoA transferase), C. acetobutylicum adc (acetoacetate decarboxylase), and C. beijerinckii adh (secondary alcohol dehydrogenase) achieved the highest titer. This strain produced 81.6 mM isopropanol in shake flasks with a yield of 43.5% (mol/mol) in the production phase. To our knowledge, this work is the first to produce isopropanol in E. coli, and the titer exceeded that from the native producers.
The defining problem in frustrated quantum magnetism, the ground state of the nearest-neighbor S=1/2 antiferromagnetic Heisenberg model on the kagome lattice, has defied all theoretical and numerical ...methods employed to date. We apply the formalism of tensor-network states, specifically the method of projected entangled simplex states, which combines infinite system size with a correct accounting for multipartite entanglement. By studying the ground-state energy, the finite magnetic order appearing at finite tensor bond dimensions, and the effects of a next-nearest-neighbor coupling, we demonstrate that the ground state is a gapless spin liquid. We discuss the comparison with other numerical studies and the physical interpretation of this result.
Non-small cell lung cancer (NSCLC) is the leading cause of cancer death, reflecting the need for better understanding the oncogenesis, and developing new diagnostic and therapeutic targets for the ...malignancy. Emerging evidence suggests that small nucleolar RNAs (snoRNAs) have malfunctioning roles in tumorigenesis. Our recent study demonstrated that small nucleolar RNA 42 (SNORA42) was overexpressed in lung tumors. Here, we investigate the role of SNORA42 in tumorigenesis of NSCLC. We simultaneously assess genomic dosages and expression levels of SNORA42 and its host gene, KIAA0907, in 10 NSCLC cell lines and a human bronchial epithelial cell line. We then determine in vitro functional significance of SNORA42 in lung cancer cell lines through gain- and loss-of-function analyses. We also inoculate cancer cells with SNORA42-siRNA into mice through either tail vein or subcutaneous injection. We finally evaluate expression level of SNORA42 on frozen surgically resected lung tumor tissues of 64 patients with stage I NSCLC by using quantitative reverse transcriptase PCR assay. Genomic amplification and associated high expression of SNORA42 rather than KIAA0907 are frequently observed in lung cancer cells, suggesting that SNORA42 overexpression is activated by its genomic amplification. SNORA42 knockdown in NSCLC cells inhibits in vitro and in vivo tumorigenicity, whereas enforced SNORA42 expression in bronchial epitheliums increases cell growth and colony formation. Such pleiotropy of SNORA42 suppression could be achieved at least partially through increased apoptosis of NSCLC cells in a p53-dependent manner. SNORA42 expression in lung tumor tissue specimens is inversely correlated with survival of NSCLC patients. Therefore, SNORA42 activation could have an oncogenic role in lung tumorigenesis and provide potential diagnostic and therapeutic targets for the malignancy.
There is an urgent need to identify therapies that prevent SARS-CoV-2 infection and improve the outcome of COVID-19 patients. Although repurposed drugs with favorable safety profiles could have ...significant benefit, widely available prevention or treatment options for COVID-19 have yet to be identified. Efforts to identify approved drugs with in vitro activity against SARS-CoV-2 resulted in identification of antiviral sigma-1 receptor ligands, including antihistamines in the histamine-1 receptor binding class. We identified antihistamine candidates for repurposing by mining electronic health records of usage in population of more than 219,000 subjects tested for SARS-CoV-2. Usage of diphenhydramine, hydroxyzine and azelastine was associated with reduced incidence of SARS-CoV-2 positivity in subjects greater than age 61. We found diphenhydramine, hydroxyzine and azelastine to exhibit direct antiviral activity against SARS-CoV-2 in vitro. Although mechanisms by which specific antihistamines exert antiviral effects is not clear, hydroxyzine, and possibly azelastine, bind Angiotensin Converting Enzyme-2 (ACE2) and the sigma-1 receptor as off-targets. Clinical studies are needed to measure the effectiveness of diphenhydramine, hydroxyzine and azelastine for disease prevention, for early intervention, or as adjuvant therapy for severe COVID-19.
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