Treatment of BRAF‐mutant melanomas with MAP kinase pathway inhibitors is paradigmatic of the promise of precision cancer therapy but also highlights problems with drug resistance that limit patient ...benefit. We use live‐cell imaging, single‐cell analysis, and molecular profiling to show that exposure of tumor cells to RAF/MEK inhibitors elicits a heterogeneous response in which some cells die, some arrest, and the remainder adapt to drug. Drug‐adapted cells up‐regulate markers of the neural crest (e.g., NGFR), a melanocyte precursor, and grow slowly. This phenotype is transiently stable, reverting to the drug‐naïve state within 9 days of drug withdrawal. Transcriptional profiling of cell lines and human tumors implicates a c‐Jun/ECM/FAK/Src cascade in de‐differentiation in about one‐third of cell lines studied; drug‐induced changes in c‐Jun and NGFR levels are also observed in xenograft and human tumors. Drugs targeting the c‐Jun/ECM/FAK/Src cascade as well as BET bromodomain inhibitors increase the maximum effect (Emax) of RAF/MEK kinase inhibitors by promoting cell killing. Thus, analysis of reversible drug resistance at a single‐cell level identifies signaling pathways and inhibitory drugs missed by assays that focus on cell populations.
Synopsis
Responses of BRAFV600E melanoma cells to vemurafenib were studied at the single‐cell level using live‐cell imaging and by transcriptional and biochemical profiling to uncover a slowly dividing, de‐differentiated cell state associated with drug resistance but inhibitable by drug combinations.
Cell‐to‐cell variability in BRAFV600E melanomas generates drug‐tolerant subpopulations.
The drug‐tolerant, slowly dividing NFGRHigh state is transiently heritable.
Drugs against a proposed c‐Jun/ECM/FAK/Src cascade block acquisition of this phenotype.
The NGFRHigh drug‐tolerant state is also blocked by BET inhibitors in vitro and in vivo.
Drugs that block adaptation by cell subpopulations increase cell killing by RAF/MEK inhibitors.
LINCS‐compliant data and methods are freely available to enhance reproducibility.
Responses of BRAFV600E melanoma cells to vemurafenib were studied at the single‐cell level using live‐cell imaging and by transcriptional and biochemical profiling to uncover a slowly dividing, de‐differentiated cell state associated with drug resistance but inhibitable by drug combinations.
The authors describe transmission of the novel coronavirus from a woman who had been living for several months in Wuhan, China, to her husband, after her return to their home in Taiwan in January ...2020. No secondary case from this couple has been identified.
Single-cell analysis reveals aspects of cellular physiology not evident from population-based studies, particularly in the case of highly multiplexed methods such as mass cytometry (CyTOF) able to ...correlate the levels of multiple signalling, differentiation and cell fate markers. Immunofluorescence (IF) microscopy adds information on cell morphology and the microenvironment that are not obtained using flow-based techniques, but the multiplicity of conventional IF is limited. This has motivated development of imaging methods that require specialized instrumentation, exotic reagents or proprietary protocols that are difficult to reproduce in most laboratories. Here we report a public-domain method for achieving high multiplicity single-cell IF using cyclic immunofluorescence (CycIF), a simple and versatile procedure in which four-colour staining alternates with chemical inactivation of fluorophores to progressively build a multichannel image. Because CycIF uses standard reagents and instrumentation and is no more expensive than conventional IF, it is suitable for high-throughput assays and screening applications.
Traditional chemotherapy is being considered due to hindrances caused by systemic toxicity. Currently, the administration of multiple chemotherapeutic drugs with different biochemical/molecular ...targets, known as combination chemotherapy, has attained numerous benefits like efficacy enhancement and amelioration of adverse effects that has been broadly applied to various cancer types. Additionally, seeking natural‐based alternatives with less toxicity has become more important. Experimental evidence suggests that herbal extracts such as Solanum nigrum and Claviceps purpurea and isolated herbal compounds (e.g., curcumin, resveratrol, and matairesinol) combined with antitumoral drugs have the potential to attenuate resistance against cancer therapy and to exert chemoprotective actions. Plant products are not free of risks: Herb adverse effects, including herb–drug interactions, should be carefully considered.
Linked Articles
This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc
The progression of colorectal carcinoma (CRC) to invasive and metastatic disease may involve localized occurrences of epithelial-mesenchymal transition (EMT). However, mechanisms of the EMT process ...in CRC progression are not fully understood. We previously showed that knockdown of signal transducer and activator of transcription 3 (STAT3) up-regulated E-cadherin (a key component in EMT progression) in CRC. In this study, we examined the roles of STAT3 in CRC EMT and ZEB1, an EMT inducer, in STAT3-induced down-regulation of E-cadherin. Knockdown of STAT3 significantly increased E-cadherin and decreased N-cadherin and vimentin expressions in highly invasive LoVo CRC cells. Meanwhile, overexpression of STAT3 significantly reduced E-cadherin and enhanced N-cadherin and vimentin expressions in weakly invasive SW1116 CRC cells. Activation of STAT3 significantly increased CRC cell invasiveness and resistance to apoptosis. Knockdown of STAT3 dramatically enhanced chemosensitivity of CRC cells to fluorouracil. STAT3 regulated ZEB1 expression in CRC cells, and the STAT3-induced decrease in E-cadherin and cell invasion depended on activation of ZEB1 in CRC cells. Additionally, pSTAT3Tyr-705 and ZEB1 expressions were significantly correlated with TNM (tumor, lymph node, and metastasis stages) (p < 0.01). In conclusion, STAT3 may directly mediate EMT progression and regulate ZEB1 expression in CRC. ZEB1 may participate in STAT3-induced cell invasion and E-cadherin down-regulation in CRC cells. The expressions of pSTAT3Tyr-705 and ZEB1 may be positively associated with CRC metastasis. Our data may provide potential targets to prevent and/or treat CRC invasion and metastasis.
Colorectal cancer (CRC) to metastatic disease may involve the epithelial-mesenchymal transition (EMT).
STAT3 may regulate N-cadherin, vimentin, and ZEB1 expressions. STAT3-induced cell invasion and down-regulation of E-cadherin may depend on ZEB1.
STAT3 may mediate CRC EMT progression and ZEB1 expression. Activation of STAT3 and ZEB1 proteins may contribute to worse prognosis in CRC patients.
Our data may provide potential targets to prevent and/or treat CRC invasion.
Multiplexed tissue imaging enables precise, spatially resolved enumeration and characterization of cell types and states in human resection specimens. A growing number of methods applicable to ...formalin-fixed, paraffin-embedded (FFPE) tissue sections have been described, the majority of which rely on antibodies for antigen detection and mapping. This protocol provides step-by-step procedures for confirming the selectivity and specificity of antibodies used in fluorescence-based tissue imaging and for the construction and validation of antibody panels. Although the protocol is implemented using tissue-based cyclic immunofluorescence (t-CyCIF) as an imaging platform, these antibody-testing methods are broadly applicable. We demonstrate assembly of a 16-antibody panel for enumerating and localizing T cells and B cells, macrophages, and cells expressing immune checkpoint regulators. The protocol is accessible to individuals with experience in microscopy and immunofluorescence; some experience in computation is required for data analysis. A typical 30-antibody dataset for 20 FFPE slides can be generated within 2 weeks.
E-learning becomes an alternative learning mode since the prevalence of the Internet. Especially, the advance of MOOC (Massive Open Online Course) technology enables a course to enroll tens of ...thousands of online learners. How to improve learners' online learning experiences on MOOC platforms becomes a crucial task for platform providers. In this research, based on Cognitive Load Theory, we built a system to capture and tag a user's mental states while s/he is watching online videos with a commercial EEG device, and used different normalization schemes and time window lengths to process EEG signals recorded from the EEG device. Finally, we adopted different supervised learning algorithms to train and test the classifiers, and then evaluated their classification performance. The results show that the proposed approach can effectively process EEG data to train classifiers, which achieve high accuracy, precision and recall rates compared with those of previous studies. This system can effectively facilitate users' self-awareness of mental efforts in online learning contexts to enable the automatic feedback in synchronous and asynchronous learning contexts, especially taking MOOCs as an example.
•Develop EEG data classification system to detect individual mental effort.•Encode EEG data to generate the best classification results.•Elaborate EEG data classification for online e-learning applications, such as MOOCs.
Currently, the commonly developed organic luminescent materials (OLMs) usually exhibit poor luminescent performance in aggregated solid states compared with their well‐dissolved solution states, ...making it a tough goal to achieve the highly emissive dual‐state emission. To overcome this limitation, a “self‐isolated enhanced emission” (SIEE) strategy through flexible alkyl chains to suppress the emission‐quenched π–π stacking in solids is proposed here and, based on this guideline, remarkable emission efficiency with photoluminescence quantum yields up to 99.72 % in solution and 77.46 % in the solid state are achieved for the SIEE constructed DBBT‐C8, which is then successfully used in solid‐state displays and data encryption.
A self‐isolated enhanced emission (SIEE) strategy through flexible alkyl chains is proposed to suppress and prevent the emission‐quenched π–π stacking in aggregated solid states. As observed, remarkable emission efficiency with quantum yields up to 99.72 % in solution and 77.46 % in solids are achieved for DBBT‐C8 (see figure).
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